16.0.12

Signed-off-by: Audrow Nash <audrow@intrinsic.ai>

README.md

@@ -8,10 +8,10 @@ rclcpp provides the standard C++ API for interacting with ROS 2.
 
 `#include "rclcpp/rclcpp.hpp"` allows use of the most common elements of the ROS 2 system.
 
-Visit the [rclcpp API documentation](http://docs.ros2.org/eloquent/api/rclcpp/) for a complete list of its main components.
+Visit the [rclcpp API documentation](http://docs.ros2.org/latest/api/rclcpp/) for a complete list of its main components.
 
 ### Examples
 
-The ROS 2 tutorials [Writing a simple publisher and subscriber](https://index.ros.org/doc/ros2/Tutorials/Writing-A-Simple-Cpp-Publisher-And-Subscriber/)
-and [Writing a simple service and client](https://index.ros.org/doc/ros2/Tutorials/Writing-A-Simple-Cpp-Service-And-Client/)
+The ROS 2 tutorials [Writing a simple publisher and subscriber](https://docs.ros.org/en/rolling/Tutorials/Writing-A-Simple-Cpp-Publisher-And-Subscriber.html).
+and [Writing a simple service and client](https://docs.ros.org/en/rolling/Tutorials/Writing-A-Simple-Cpp-Service-And-Client.html)
 contain some examples of rclcpp APIs in use.

rclcpp/CHANGELOG.rst

@@ -2,6 +2,666 @@
 Changelog for package rclcpp
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+16.0.12 (2025-03-25)
+--------------------
+* doc: Added warning to not instantiate Clock directly with RCL_ROS_TIME (`#2768 <https://github.com/ros2/rclcpp/issues/2768>`_) (`#2770 <https://github.com/ros2/rclcpp/issues/2770>`_)
+* apply actual QoS from rmw to the IPC publisher. (backport `#2707 <https://github.com/ros2/rclcpp/issues/2707>`_) (`#2711 <https://github.com/ros2/rclcpp/issues/2711>`_)
+* Adding in topic name to logging on IPC issues (`#2706 <https://github.com/ros2/rclcpp/issues/2706>`_) (`#2709 <https://github.com/ros2/rclcpp/issues/2709>`_)
+* Contributors: mergify[bot]
+
+16.0.11 (2024-11-25)
+--------------------
+* Fix subscription.is_serialized() for callbacks with message info (`#1950 <https://github.com/ros2/rclcpp/issues/1950>`_) (`#2622 <https://github.com/ros2/rclcpp/issues/2622>`_)
+* Use the same context for the specified node in rclcpp::spin functions… (`#2618 <https://github.com/ros2/rclcpp/issues/2618>`_) (`#2620 <https://github.com/ros2/rclcpp/issues/2620>`_)
+* Contributors: mergify[bot], roscan-tech
+
+16.0.10 (2024-07-26)
+--------------------
+* Add test creating two content filter topics with the same topic name (`#2546 <https://github.com/ros2/rclcpp/issues/2546>`_) (`#2549 <https://github.com/ros2/rclcpp/issues/2549>`_) (`#2551 <https://github.com/ros2/rclcpp/issues/2551>`_)
+* Contributors: mergify[bot]
+
+16.0.9 (2024-05-15)
+-------------------
+* Fix logging macros to build with msvc and cpp20 (`#2063 <https://github.com/ros2/rclcpp/issues/2063>`_) (`#2529 <https://github.com/ros2/rclcpp/issues/2529>`_)
+* address ambiguous auto variable. (`#2481 <https://github.com/ros2/rclcpp/issues/2481>`_) (`#2485 <https://github.com/ros2/rclcpp/issues/2485>`_)
+* Fix clang warning: bugprone-use-after-move (`#2116 <https://github.com/ros2/rclcpp/issues/2116>`_) (`#2459 <https://github.com/ros2/rclcpp/issues/2459>`_)
+* Contributors: Tamaki Nishino, mergify[bot]
+
+16.0.8 (2024-01-24)
+-------------------
+* Add missing stdexcept include (`#2186 <https://github.com/ros2/rclcpp/issues/2186>`_) (`#2394 <https://github.com/ros2/rclcpp/issues/2394>`_)
+* Contributors: gentoo90
+
+16.0.7 (2023-11-13)
+-------------------
+* Disable the loaned messages inside the executor. (backport `#2335 <https://github.com/ros2/rclcpp/issues/2335>`_) (`#2364 <https://github.com/ros2/rclcpp/issues/2364>`_)
+* Add missing 'enable_rosout' comments (`#2345 <https://github.com/ros2/rclcpp/issues/2345>`_) (`#2347 <https://github.com/ros2/rclcpp/issues/2347>`_)
+* address rate related flaky tests. (`#2329 <https://github.com/ros2/rclcpp/issues/2329>`_) (`#2342 <https://github.com/ros2/rclcpp/issues/2342>`_)
+* Update SignalHandler get_global_signal_handler to avoid complex types in static memory (`#2316 <https://github.com/ros2/rclcpp/issues/2316>`_) (`#2321 <https://github.com/ros2/rclcpp/issues/2321>`_)
+* Fix C++20 allocator construct deprecation (`#2292 <https://github.com/ros2/rclcpp/issues/2292>`_) (`#2319 <https://github.com/ros2/rclcpp/issues/2319>`_)
+* Contributors: mergify[bot]
+
+16.0.6 (2023-09-19)
+-------------------
+* Topic correct typeadapter deduction (`#2294 <https://github.com/ros2/rclcpp/issues/2294>`_) (`#2297 <https://github.com/ros2/rclcpp/issues/2297>`_)
+* check thread whether joinable before join (`#2019 <https://github.com/ros2/rclcpp/issues/2019>`_) (`#2275 <https://github.com/ros2/rclcpp/issues/2275>`_)
+* Do not crash Executor when send_response fails due to client failure. (`#2276 <https://github.com/ros2/rclcpp/issues/2276>`_) (`#2280 <https://github.com/ros2/rclcpp/issues/2280>`_)
+* Contributors: mergify[bot]
+
+16.0.5 (2023-07-17)
+-------------------
+* warning: comparison of integer expressions of different signedness (`#2219 <https://github.com/ros2/rclcpp/issues/2219>`_) (`#2223 <https://github.com/ros2/rclcpp/issues/2223>`_)
+* Trigger the intraprocess guard condition with data (`#2164 <https://github.com/ros2/rclcpp/issues/2164>`_) (`#2167 <https://github.com/ros2/rclcpp/issues/2167>`_)
+* Implement validity checks for rclcpp::Clock (`#2040 <https://github.com/ros2/rclcpp/issues/2040>`_) (`#2210 <https://github.com/ros2/rclcpp/issues/2210>`_)
+* Contributors: Tomoya Fujita, mergify[bot]
+
+16.0.4 (2023-04-25)
+-------------------
+* use allocator via init_options argument. (`#2129 <https://github.com/ros2/rclcpp/issues/2129>`_) (`#2131 <https://github.com/ros2/rclcpp/issues/2131>`_)
+* Contributors: mergify[bot]
+
+16.0.3 (2023-01-10)
+-------------------
+* Fix SharedFuture from async_send_request never becomes valid (`#2044 <https://github.com/ros2/rclcpp/issues/2044>`_) (`#2076 <https://github.com/ros2/rclcpp/issues/2076>`_)
+* do not throw exception if trying to dequeue an empty intra-process buffer (`#2061 <https://github.com/ros2/rclcpp/issues/2061>`_) (`#2070 <https://github.com/ros2/rclcpp/issues/2070>`_)
+* fix nullptr dereference in prune_requests_older_than (`#2008 <https://github.com/ros2/rclcpp/issues/2008>`_) (`#2065 <https://github.com/ros2/rclcpp/issues/2065>`_)
+* Fix bug that a callback not reached (`#1640 <https://github.com/ros2/rclcpp/issues/1640>`_) (`#2033 <https://github.com/ros2/rclcpp/issues/2033>`_)
+* Contributors: mergify[bot]
+
+16.0.2 (2022-11-07)
+-------------------
+* fix mismatched issue if using zero_allocate (`#1995 <https://github.com/ros2/rclcpp/issues/1995>`_) (`#2026 <https://github.com/ros2/rclcpp/issues/2026>`_)
+* use regex for wildcard matching (backport `#1839 <https://github.com/ros2/rclcpp/issues/1839>`_) (`#1986 <https://github.com/ros2/rclcpp/issues/1986>`_)
+* Drop wrong template specialization (`#1926 <https://github.com/ros2/rclcpp/issues/1926>`_) (`#1937 <https://github.com/ros2/rclcpp/issues/1937>`_)
+* Add statistics for handle_loaned_message (`#1927 <https://github.com/ros2/rclcpp/issues/1927>`_) (`#1932 <https://github.com/ros2/rclcpp/issues/1932>`_)
+* Contributors: mergify[bot]
+
+16.0.1 (2022-04-13)
+-------------------
+* remove DEFINE_CONTENT_FILTER cmake option (`#1914 <https://github.com/ros2/rclcpp/issues/1914>`_)
+* Contributors: Chen Lihui
+
+16.0.0 (2022-04-08)
+-------------------
+* remove things that were deprecated during galactic (`#1913 <https://github.com/ros2/rclcpp/issues/1913>`_)
+* Contributors: William Woodall
+
+15.4.0 (2022-04-05)
+-------------------
+* add take_data_by_entity_id API to waitable (`#1892 <https://github.com/ros2/rclcpp/issues/1892>`_)
+* add content-filtered-topic interfaces (`#1561 <https://github.com/ros2/rclcpp/issues/1561>`_)
+* Contributors: Alberto Soragna, Chen Lihui
+
+15.3.0 (2022-03-30)
+-------------------
+* [NodeParameters] Set name in param info pre-check (`#1908 <https://github.com/ros2/rclcpp/issues/1908>`_)
+* Add test-dep ament_cmake_google_benchmark (`#1904 <https://github.com/ros2/rclcpp/issues/1904>`_)
+* Add publish by loaned message in GenericPublisher (`#1856 <https://github.com/ros2/rclcpp/issues/1856>`_)
+* Contributors: Abrar Rahman Protyasha, Barry Xu, Gaël Écorchard
+
+15.2.0 (2022-03-24)
+-------------------
+* Add missing ament dependency on rcl_interfaces (`#1903 <https://github.com/ros2/rclcpp/issues/1903>`_)
+* Update data callback tests to account for all published samples (`#1900 <https://github.com/ros2/rclcpp/issues/1900>`_)
+* Increase timeout for acknowledgments to account for slower Connext settings (`#1901 <https://github.com/ros2/rclcpp/issues/1901>`_)
+* clang-tidy: explicit constructors (`#1782 <https://github.com/ros2/rclcpp/issues/1782>`_)
+* Add client/service QoS getters (`#1784 <https://github.com/ros2/rclcpp/issues/1784>`_)
+* Fix a bunch more rosdoc2 issues in rclcpp. (`#1897 <https://github.com/ros2/rclcpp/issues/1897>`_)
+* time_until_trigger returns max time if timer is cancelled (`#1893 <https://github.com/ros2/rclcpp/issues/1893>`_)
+* Micro-optimizations in rclcpp (`#1896 <https://github.com/ros2/rclcpp/issues/1896>`_)
+* Contributors: Andrea Sorbini, Chris Lalancette, Mauro Passerino, Scott K Logan, William Woodall
+
+15.1.0 (2022-03-01)
+-------------------
+* spin_all with a zero timeout. (`#1878 <https://github.com/ros2/rclcpp/issues/1878>`_)
+* Add RMW listener APIs (`#1579 <https://github.com/ros2/rclcpp/issues/1579>`_)
+* Remove fastrtps customization on tests (`#1887 <https://github.com/ros2/rclcpp/issues/1887>`_)
+* Install headers to include/${PROJECT_NAME} (`#1888 <https://github.com/ros2/rclcpp/issues/1888>`_)
+* Use ament_generate_version_header (`#1886 <https://github.com/ros2/rclcpp/issues/1886>`_)
+* use universal reference to support rvalue. (`#1883 <https://github.com/ros2/rclcpp/issues/1883>`_)
+* fix one subscription can wait_for_message twice (`#1870 <https://github.com/ros2/rclcpp/issues/1870>`_)
+* Add return value version of get_parameter_or (`#1813 <https://github.com/ros2/rclcpp/issues/1813>`_)
+* Cleanup time source object lifetimes (`#1867 <https://github.com/ros2/rclcpp/issues/1867>`_)
+* add is_spinning() method to executor base class
+* Contributors: Alberto Soragna, Chen Lihui, Chris Lalancette, Kenji Miyake, Miguel Company, Shane Loretz, Tomoya Fujita, iRobot ROS
+
+15.0.0 (2022-01-14)
+-------------------
+* Cleanup the TypeAdapt tests (`#1858 <https://github.com/ros2/rclcpp/issues/1858>`_)
+* Cleanup includes (`#1857 <https://github.com/ros2/rclcpp/issues/1857>`_)
+* Fix include order and relative paths for cpplint (`#1859 <https://github.com/ros2/rclcpp/issues/1859>`_)
+* Rename stringstream in macros to a more unique name (`#1862 <https://github.com/ros2/rclcpp/issues/1862>`_)
+* Add non transform capabilities for intra-process (`#1849 <https://github.com/ros2/rclcpp/issues/1849>`_)
+* Fix rclcpp documentation build (`#1779 <https://github.com/ros2/rclcpp/issues/1779>`_)
+* Contributors: Chris Lalancette, Doug Smith, Gonzo, Jacob Perron, Michel Hidalgo
+
+14.1.0 (2022-01-05)
+-------------------
+* Use UninitializedStaticallyTypedParameterException (`#1689 <https://github.com/ros2/rclcpp/issues/1689>`_)
+* Add wait_for_all_acked support (`#1662 <https://github.com/ros2/rclcpp/issues/1662>`_)
+* Add tests for function templates of declare_parameter (`#1747 <https://github.com/ros2/rclcpp/issues/1747>`_)
+* Contributors: Barry Xu, Bi0T1N, M. Mostafa Farzan
+
+14.0.0 (2021-12-17)
+-------------------
+* Fixes for uncrustify 0.72 (`#1844 <https://github.com/ros2/rclcpp/issues/1844>`_)
+* use private member to keep the all reference underneath. (`#1845 <https://github.com/ros2/rclcpp/issues/1845>`_)
+* Make node base sharable (`#1832 <https://github.com/ros2/rclcpp/issues/1832>`_)
+* Add Clock::sleep_for() (`#1828 <https://github.com/ros2/rclcpp/issues/1828>`_)
+* Synchronize rcl and std::chrono steady clocks in Clock::sleep_until (`#1830 <https://github.com/ros2/rclcpp/issues/1830>`_)
+* Use rclcpp::guard_condition (`#1612 <https://github.com/ros2/rclcpp/issues/1612>`_)
+* Call CMake function to generate version header (`#1805 <https://github.com/ros2/rclcpp/issues/1805>`_)
+* Use parantheses around logging macro parameter (`#1820 <https://github.com/ros2/rclcpp/issues/1820>`_)
+* Remove author by request (`#1818 <https://github.com/ros2/rclcpp/issues/1818>`_)
+* Update maintainers (`#1817 <https://github.com/ros2/rclcpp/issues/1817>`_)
+* min_forward & min_backward thresholds must not be disabled (`#1815 <https://github.com/ros2/rclcpp/issues/1815>`_)
+* Re-add Clock::sleep_until (`#1814 <https://github.com/ros2/rclcpp/issues/1814>`_)
+* Fix lifetime of context so it remains alive while its dependent node handles are still in use (`#1754 <https://github.com/ros2/rclcpp/issues/1754>`_)
+* Add the interface for pre-shutdown callback (`#1714 <https://github.com/ros2/rclcpp/issues/1714>`_)
+* Take message ownership from moved LoanedMessage (`#1808 <https://github.com/ros2/rclcpp/issues/1808>`_)
+* Suppress clang dead-store warnings in the benchmarks. (`#1802 <https://github.com/ros2/rclcpp/issues/1802>`_)
+* Wait for publisher and subscription to match (`#1777 <https://github.com/ros2/rclcpp/issues/1777>`_)
+* Fix unused QoS profile for clock subscription and make ClockQoS the default (`#1801 <https://github.com/ros2/rclcpp/issues/1801>`_)
+* Contributors: Abrar Rahman Protyasha, Barry Xu, Chen Lihui, Chris Lalancette, Grey, Jacob Perron, Nikolai Morin, Shane Loretz, Tomoya Fujita, mauropasse
+
+13.1.0 (2021-10-18)
+-------------------
+* Fix dangerous std::bind capture in TimeSource implementation. (`#1768 <https://github.com/ros2/rclcpp/issues/1768>`_)
+* Fix dangerous std::bind capture in ParameterEventHandler implementation. (`#1770 <https://github.com/ros2/rclcpp/issues/1770>`_)
+* Handle sigterm, in the same way sigint is being handled. (`#1771 <https://github.com/ros2/rclcpp/issues/1771>`_)
+* rclcpp::Node copy constructor: make copy of node_waitables\_ member. (`#1799 <https://github.com/ros2/rclcpp/issues/1799>`_)
+* Extend NodeGraph to match what rcl provides. (`#1484 <https://github.com/ros2/rclcpp/issues/1484>`_)
+* Context::sleep_for(): replace recursion with do-while to avoid potential stack-overflow. (`#1765 <https://github.com/ros2/rclcpp/issues/1765>`_)
+* extend_sub_namespace(): Verify string::empty() before calling string::front(). (`#1764 <https://github.com/ros2/rclcpp/issues/1764>`_)
+* Deprecate the `void shared_ptr<MessageT>` subscription callback signatures. (`#1713 <https://github.com/ros2/rclcpp/issues/1713>`_)
+* Contributors: Abrar Rahman Protyasha, Chris Lalancette, Emerson Knapp, Geoffrey Biggs, Ivan Santiago Paunovic, Jorge Perez, Tomoya Fujita, William Woodall, Yong-Hao Zou, livanov93
+
+13.0.0 (2021-08-23)
+-------------------
+* Remove can_be_nullptr assignment check for QNX case. (`#1752 <https://github.com/ros2/rclcpp/issues/1752>`_)
+* Update client API to be able to remove pending requests. (`#1734 <https://github.com/ros2/rclcpp/issues/1734>`_)
+* Fix: Allow to add a node while spinning in the StaticSingleThreadedExecutor. (`#1690 <https://github.com/ros2/rclcpp/issues/1690>`_)
+* Add tracing instrumentation for executor and message taking. (`#1738 <https://github.com/ros2/rclcpp/issues/1738>`_)
+* Fix: Reset timer trigger time before execute in StaticSingleThreadedExecutor. (`#1739 <https://github.com/ros2/rclcpp/issues/1739>`_)
+* Use FindPython3 and make python3 dependency explicit. (`#1745 <https://github.com/ros2/rclcpp/issues/1745>`_)
+* Use rosidl_get_typesupport_target(). (`#1729 <https://github.com/ros2/rclcpp/issues/1729>`_)
+* Fix returning invalid namespace if sub_namespace is empty. (`#1658 <https://github.com/ros2/rclcpp/issues/1658>`_)
+* Add free function to wait for a subscription message. (`#1705 <https://github.com/ros2/rclcpp/issues/1705>`_)
+* Use rcpputils/scope_exit.hpp and remove rclcpp/scope_exit.hpp. (`#1727 <https://github.com/ros2/rclcpp/issues/1727>`_)
+* Contributors: Ahmed Sobhy, Christophe Bedard, Ivan Santiago Paunovic, Karsten Knese, M. Hofstätter, Mauro Passerino, Shane Loretz, mauropasse
+
+12.0.0 (2021-07-26)
+-------------------
+* Remove unsafe get_callback_groups API.
+  Callers should change to using for_each_callback_group(), or
+  store the callback groups they need internally.
+* Add in callback_groups_for_each.
+  The main reason to add this method in is to make accesses to the
+  callback_groups\_ vector thread-safe.  By having a
+  callback_groups_for_each that accepts a std::function, we can
+  just have the callers give us the callback they are interested
+  in, and we can take care of the locking.
+  The rest of this fairly large PR is cleaning up all of the places
+  that use get_callback_groups() to instead use
+  callback_groups_for_each().
+* Use a different mechanism to avoid timers being scheduled multiple times by the MultiThreadedExecutor (`#1692 <https://github.com/ros2/rclcpp/issues/1692>`_)
+* Fix windows CI (`#1726 <https://github.com/ros2/rclcpp/issues/1726>`_)
+  Fix bug in AnyServiceCallback introduced in `#1709 <https://github.com/ros2/rclcpp/issues/1709>`_.
+* Contributors: Chris Lalancette, Ivan Santiago Paunovic
+
+11.2.0 (2021-07-21)
+-------------------
+* Support to defer to send a response in services. (`#1709 <https://github.com/ros2/rclcpp/issues/1709>`_)
+  Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>
+* Fix documentation bug. (`#1719 <https://github.com/ros2/rclcpp/issues/1719>`_)
+  Signed-off-by: William Woodall <william@osrfoundation.org>
+* Contributors: Ivan Santiago Paunovic, William Woodall
+
+11.1.0 (2021-07-13)
+-------------------
+* Removed left over ``is_initialized()`` implementation (`#1711 <https://github.com/ros2/rclcpp/issues/1711>`_)
+  Leftover from https://github.com/ros2/rclcpp/pull/1622
+* Fixed declare parameter methods for int and float vectors (`#1696 <https://github.com/ros2/rclcpp/issues/1696>`_)
+* Cleaned up implementation of the intra-process manager (`#1695 <https://github.com/ros2/rclcpp/issues/1695>`_)
+* Added the node name to an executor ``runtime_error`` (`#1686 <https://github.com/ros2/rclcpp/issues/1686>`_)
+* Fixed a typo "Attack" -> "Attach" (`#1687 <https://github.com/ros2/rclcpp/issues/1687>`_)
+* Removed use of std::allocator<>::rebind (`#1678 <https://github.com/ros2/rclcpp/issues/1678>`_)
+  rebind is deprecated in c++17 and removed in c++20
+* Contributors: Alberto Soragna, Chen Lihui, Chris Lalancette, Petter Nilsson, Steve Macenski, William Woodall
+
+11.0.0 (2021-05-18)
+-------------------
+* Allow declare uninitialized parameters (`#1673 <https://github.com/ros2/rclcpp/issues/1673>`_)
+* Fix syntax issue with gcc (`#1674 <https://github.com/ros2/rclcpp/issues/1674>`_)
+* [service] Don't use a weak_ptr to avoid leaking (`#1668 <https://github.com/ros2/rclcpp/issues/1668>`_)
+* Contributors: Ivan Santiago Paunovic, Jacob Perron, William Woodall
+
+10.0.0 (2021-05-11)
+-------------------
+* Fix doc typo (`#1663 <https://github.com/ros2/rclcpp/issues/1663>`_)
+* [rclcpp] Type Adaptation feature (`#1557 <https://github.com/ros2/rclcpp/issues/1557>`_)
+* Do not attempt to use void allocators for memory allocation. (`#1657 <https://github.com/ros2/rclcpp/issues/1657>`_)
+* Keep custom allocator in publisher and subscription options alive. (`#1647 <https://github.com/ros2/rclcpp/issues/1647>`_)
+* Fix get_publishers_subscriptions_info_by_topic test in test_node.cpp (`#1648 <https://github.com/ros2/rclcpp/issues/1648>`_)
+* Use OnShutdown callback handle instead of OnShutdown callback (`#1639 <https://github.com/ros2/rclcpp/issues/1639>`_)
+* use dynamic_pointer_cast to detect allocator mismatch in intra process manager (`#1643 <https://github.com/ros2/rclcpp/issues/1643>`_)
+* Increase cppcheck timeout to 500s (`#1634 <https://github.com/ros2/rclcpp/issues/1634>`_)
+* Clarify node parameters docs (`#1631 <https://github.com/ros2/rclcpp/issues/1631>`_)
+* Contributors: Audrow Nash, Barry Xu, Jacob Perron, Michel Hidalgo, Shane Loretz, William Woodall
+
+9.0.2 (2021-04-14)
+------------------
+* Avoid returning loan when none was obtained. (`#1629 <https://github.com/ros2/rclcpp/issues/1629>`_)
+* Use a different implementation of mutex two priorities (`#1628 <https://github.com/ros2/rclcpp/issues/1628>`_)
+* Do not test the value of the history policy when testing the get_publishers/subscriptions_info_by_topic() methods (`#1626 <https://github.com/ros2/rclcpp/issues/1626>`_)
+* Check first parameter type and range before calling the user validation callbacks (`#1627 <https://github.com/ros2/rclcpp/issues/1627>`_)
+* Contributors: Ivan Santiago Paunovic, Miguel Company
+
+9.0.1 (2021-04-12)
+------------------
+* Restore test exception for Connext (`#1625 <https://github.com/ros2/rclcpp/issues/1625>`_)
+* Fix race condition in TimeSource clock thread setup (`#1623 <https://github.com/ros2/rclcpp/issues/1623>`_)
+* Contributors: Andrea Sorbini, Michel Hidalgo
+
+9.0.0 (2021-04-06)
+------------------
+* remove deprecated code which was deprecated in foxy and should be removed in galactic (`#1622 <https://github.com/ros2/rclcpp/issues/1622>`_)
+* Change index.ros.org -> docs.ros.org. (`#1620 <https://github.com/ros2/rclcpp/issues/1620>`_)
+* Unique network flows (`#1496 <https://github.com/ros2/rclcpp/issues/1496>`_)
+* Add spin_some support to the StaticSingleThreadedExecutor (`#1338 <https://github.com/ros2/rclcpp/issues/1338>`_)
+* Add publishing instrumentation (`#1600 <https://github.com/ros2/rclcpp/issues/1600>`_)
+* Create load_parameters and delete_parameters methods (`#1596 <https://github.com/ros2/rclcpp/issues/1596>`_)
+* refactor AnySubscriptionCallback and add/deprecate callback signatures (`#1598 <https://github.com/ros2/rclcpp/issues/1598>`_)
+* Add generic publisher and generic subscription for serialized messages (`#1452 <https://github.com/ros2/rclcpp/issues/1452>`_)
+* use context from `node_base\_` for clock executor. (`#1617 <https://github.com/ros2/rclcpp/issues/1617>`_)
+* updating quality declaration links (re: `ros2/docs.ros2.org#52 <https://github.com/ros2/docs.ros2.org/issues/52>`_) (`#1615 <https://github.com/ros2/rclcpp/issues/1615>`_)
+* Contributors: Ananya Muddukrishna, BriceRenaudeau, Chris Lalancette, Christophe Bedard, Nikolai Morin, Tomoya Fujita, William Woodall, mauropasse, shonigmann
+
+8.2.0 (2021-03-31)
+------------------
+* Initialize integers in test_parameter_event_handler.cpp to avoid undefined behavior (`#1609 <https://github.com/ros2/rclcpp/issues/1609>`_)
+* Namespace tracetools C++ functions (`#1608 <https://github.com/ros2/rclcpp/issues/1608>`_)
+* Revert "Namespace tracetools C++ functions (`#1603 <https://github.com/ros2/rclcpp/issues/1603>`_)" (`#1607 <https://github.com/ros2/rclcpp/issues/1607>`_)
+* Namespace tracetools C++ functions (`#1603 <https://github.com/ros2/rclcpp/issues/1603>`_)
+* Clock subscription callback group spins in its own thread (`#1556 <https://github.com/ros2/rclcpp/issues/1556>`_)
+* Contributors: Chris Lalancette, Christophe Bedard, Ivan Santiago Paunovic, anaelle-sw
+
+8.1.0 (2021-03-25)
+------------------
+* Remove rmw_connext_cpp references. (`#1595 <https://github.com/ros2/rclcpp/issues/1595>`_)
+* Add API for checking QoS profile compatibility (`#1554 <https://github.com/ros2/rclcpp/issues/1554>`_)
+* Document misuse of parameters callback (`#1590 <https://github.com/ros2/rclcpp/issues/1590>`_)
+* use const auto & to iterate over parameters (`#1593 <https://github.com/ros2/rclcpp/issues/1593>`_)
+* Contributors: Chris Lalancette, Jacob Perron, Karsten Knese
+
+8.0.0 (2021-03-23)
+------------------
+* Guard against integer overflow in duration conversion (`#1584 <https://github.com/ros2/rclcpp/issues/1584>`_)
+* Contributors: Jacob Perron
+
+7.0.1 (2021-03-22)
+------------------
+* get_parameters service should return empty if undeclared parameters are allowed (`#1514 <https://github.com/ros2/rclcpp/issues/1514>`_)
+* Made 'Context::shutdown_reason' function a const function (`#1578 <https://github.com/ros2/rclcpp/issues/1578>`_)
+* Contributors: Tomoya Fujita, suab321321
+
+7.0.0 (2021-03-18)
+------------------
+* Document design decisions that were made for statically typed parameters (`#1568 <https://github.com/ros2/rclcpp/issues/1568>`_)
+* Fix doc typo in CallbackGroup constructor (`#1582 <https://github.com/ros2/rclcpp/issues/1582>`_)
+* Enable qos parameter overrides for the /parameter_events topic  (`#1532 <https://github.com/ros2/rclcpp/issues/1532>`_)
+* Add support for rmw_connextdds (`#1574 <https://github.com/ros2/rclcpp/issues/1574>`_)
+* Remove 'struct' from the rcl_time_jump_t. (`#1577 <https://github.com/ros2/rclcpp/issues/1577>`_)
+* Add tests for declaring statically typed parameters when undeclared parameters are allowed (`#1575 <https://github.com/ros2/rclcpp/issues/1575>`_)
+* Quiet clang memory leak warning on "DoNotOptimize". (`#1571 <https://github.com/ros2/rclcpp/issues/1571>`_)
+* Add ParameterEventsSubscriber class (`#829 <https://github.com/ros2/rclcpp/issues/829>`_)
+* When a parameter change is rejected, the parameters map shouldn't be updated. (`#1567 <https://github.com/ros2/rclcpp/pull/1567>`_)
+* Fix when to throw the NoParameterOverrideProvided exception. (`#1567 <https://github.com/ros2/rclcpp/pull/1567>`_)
+* Fix SEGV caused by order of destruction of Node sub-interfaces (`#1469 <https://github.com/ros2/rclcpp/issues/1469>`_)
+* Fix benchmark test failure introduced in `#1522 <https://github.com/ros2/rclcpp/issues/1522>`_ (`#1564 <https://github.com/ros2/rclcpp/issues/1564>`_)
+* Fix documented example in create_publisher (`#1558 <https://github.com/ros2/rclcpp/issues/1558>`_)
+* Enforce static parameter types (`#1522 <https://github.com/ros2/rclcpp/issues/1522>`_)
+* Allow timers to keep up the intended rate in MultiThreadedExecutor (`#1516 <https://github.com/ros2/rclcpp/issues/1516>`_)
+* Fix UBSAN warnings in any_subscription_callback. (`#1551 <https://github.com/ros2/rclcpp/issues/1551>`_)
+* Fix runtime error: reference binding to null pointer of type (`#1547 <https://github.com/ros2/rclcpp/issues/1547>`_)
+* Contributors: Andrea Sorbini, Chris Lalancette, Colin MacKenzie, Ivan Santiago Paunovic, Jacob Perron, Steven! Ragnarök, bpwilcox, tomoya
+
+6.3.1 (2021-02-08)
+------------------
+* Reference test resources directly from source tree (`#1543 <https://github.com/ros2/rclcpp/issues/1543>`_)
+* clear statistics after window reset (`#1531 <https://github.com/ros2/rclcpp/issues/1531>`_) (`#1535 <https://github.com/ros2/rclcpp/issues/1535>`_)
+* Fix a minor string error in the topic_statistics test. (`#1541 <https://github.com/ros2/rclcpp/issues/1541>`_)
+* Avoid `Resource deadlock avoided` if use intra_process_comms (`#1530 <https://github.com/ros2/rclcpp/issues/1530>`_)
+* Avoid an object copy in parameter_value.cpp. (`#1538 <https://github.com/ros2/rclcpp/issues/1538>`_)
+* Assert that the publisher_list size is 1. (`#1537 <https://github.com/ros2/rclcpp/issues/1537>`_)
+* Don't access objects after they have been std::move (`#1536 <https://github.com/ros2/rclcpp/issues/1536>`_)
+* Update for checking correct variable (`#1534 <https://github.com/ros2/rclcpp/issues/1534>`_)
+* Destroy msg extracted from LoanedMessage. (`#1305 <https://github.com/ros2/rclcpp/issues/1305>`_)
+* Contributors: Chen Lihui, Chris Lalancette, Ivan Santiago Paunovic, Miaofei Mei, Scott K Logan, William Woodall, hsgwa
+
+6.3.0 (2021-01-25)
+------------------
+* Add instrumentation for linking a timer to a node (`#1500 <https://github.com/ros2/rclcpp/issues/1500>`_)
+* Fix error when using IPC with StaticSingleThreadExecutor (`#1520 <https://github.com/ros2/rclcpp/issues/1520>`_)
+* Change to using unique_ptrs for DummyExecutor. (`#1517 <https://github.com/ros2/rclcpp/issues/1517>`_)
+* Allow reconfiguring 'clock' topic qos (`#1512 <https://github.com/ros2/rclcpp/issues/1512>`_)
+* Allow to add/remove nodes thread safely in rclcpp::Executor  (`#1505 <https://github.com/ros2/rclcpp/issues/1505>`_)
+* Call rclcpp::shutdown in test_node for clean shutdown on Windows (`#1515 <https://github.com/ros2/rclcpp/issues/1515>`_)
+* Reapply "Add get_logging_directory method to rclcpp::Logger (`#1509 <https://github.com/ros2/rclcpp/issues/1509>`_)" (`#1513 <https://github.com/ros2/rclcpp/issues/1513>`_)
+* use describe_parameters of parameter client for test (`#1499 <https://github.com/ros2/rclcpp/issues/1499>`_)
+* Revert "Add get_logging_directory method to rclcpp::Logger (`#1509 <https://github.com/ros2/rclcpp/issues/1509>`_)" (`#1511 <https://github.com/ros2/rclcpp/issues/1511>`_)
+* Add get_logging_directory method to rclcpp::Logger (`#1509 <https://github.com/ros2/rclcpp/issues/1509>`_)
+* Contributors: Chris Lalancette, Christophe Bedard, Ivan Santiago Paunovic, eboasson, mauropasse, tomoya
+
+6.2.0 (2021-01-08)
+------------------
+* Better documentation for the QoS class (`#1508 <https://github.com/ros2/rclcpp/issues/1508>`_)
+* Modify excluding callback duration from topic statistics (`#1492 <https://github.com/ros2/rclcpp/issues/1492>`_)
+* Make the test of graph users more robust. (`#1504 <https://github.com/ros2/rclcpp/issues/1504>`_)
+* Make sure to wait for graph change events in test_node_graph. (`#1503 <https://github.com/ros2/rclcpp/issues/1503>`_)
+* add timeout to SyncParametersClient methods (`#1493 <https://github.com/ros2/rclcpp/issues/1493>`_)
+* Fix wrong test expectations (`#1497 <https://github.com/ros2/rclcpp/issues/1497>`_)
+* Update create_publisher/subscription documentation, clarifying when a parameters interface is required (`#1494 <https://github.com/ros2/rclcpp/issues/1494>`_)
+* Fix string literal warnings (`#1442 <https://github.com/ros2/rclcpp/issues/1442>`_)
+* support describe_parameters methods to parameter client. (`#1453 <https://github.com/ros2/rclcpp/issues/1453>`_)
+* Contributors: Audrow Nash, Chris Lalancette, Ivan Santiago Paunovic, Nikolai Morin, hsgwa, tomoya
+
+6.1.0 (2020-12-10)
+------------------
+* Add getters to rclcpp::qos and rclcpp::Policy enum classes (`#1467 <https://github.com/ros2/rclcpp/issues/1467>`_)
+* Change nullptr checks to use ASSERT_TRUE. (`#1486 <https://github.com/ros2/rclcpp/issues/1486>`_)
+* Adjust logic around finding and erasing guard_condition (`#1474 <https://github.com/ros2/rclcpp/issues/1474>`_)
+* Update QDs to QL 1 (`#1477 <https://github.com/ros2/rclcpp/issues/1477>`_)
+* Add performance tests for parameter transport (`#1463 <https://github.com/ros2/rclcpp/issues/1463>`_)
+* Contributors: Chris Lalancette, Ivan Santiago Paunovic, Scott K Logan, Stephen Brawner
+
+6.0.0 (2020-11-18)
+------------------
+* Move ownership of shutdown_guard_condition to executors/graph_listener (`#1404 <https://github.com/ros2/rclcpp/issues/1404>`_)
+* Add options to automatically declare qos parameters when creating a publisher/subscription (`#1465 <https://github.com/ros2/rclcpp/issues/1465>`_)
+* Add `take_data` to `Waitable` and `data` to `AnyExecutable` (`#1241 <https://github.com/ros2/rclcpp/issues/1241>`_)
+* Add benchmarks for node parameters interface (`#1444 <https://github.com/ros2/rclcpp/issues/1444>`_)
+* Remove allocation from executor::remove_node() (`#1448 <https://github.com/ros2/rclcpp/issues/1448>`_)
+* Fix test crashes on CentOS 7 (`#1449 <https://github.com/ros2/rclcpp/issues/1449>`_)
+* Bump rclcpp packages to Quality Level 2 (`#1445 <https://github.com/ros2/rclcpp/issues/1445>`_)
+* Added executor benchmark tests (`#1413 <https://github.com/ros2/rclcpp/issues/1413>`_)
+* Add fully-qualified namespace to WeakCallbackGroupsToNodesMap (`#1435 <https://github.com/ros2/rclcpp/issues/1435>`_)
+* Contributors: Alejandro Hernández Cordero, Audrow Nash, Chris Lalancette, Ivan Santiago Paunovic, Louise Poubel, Scott K Logan, brawner
+
+5.1.0 (2020-11-02)
+------------------
+* Deprecate Duration(rcl_duration_value_t) in favor of static Duration::from_nanoseconds(rcl_duration_value_t) (`#1432 <https://github.com/ros2/rclcpp/issues/1432>`_)
+* Avoid parsing arguments twice in `rclcpp::init_and_remove_ros_arguments` (`#1415 <https://github.com/ros2/rclcpp/issues/1415>`_)
+* Add service and client benchmarks (`#1425 <https://github.com/ros2/rclcpp/issues/1425>`_)
+* Set CMakeLists to only use default rmw for benchmarks (`#1427 <https://github.com/ros2/rclcpp/issues/1427>`_)
+* Update tracetools' QL in rclcpp's QD (`#1428 <https://github.com/ros2/rclcpp/issues/1428>`_)
+* Add missing locking to the rclcpp_action::ServerBase. (`#1421 <https://github.com/ros2/rclcpp/issues/1421>`_)
+* Initial benchmark tests for rclcpp::init/shutdown create/destroy node (`#1411 <https://github.com/ros2/rclcpp/issues/1411>`_)
+* Refactor test CMakeLists in prep for benchmarks (`#1422 <https://github.com/ros2/rclcpp/issues/1422>`_)
+* Add methods in topic and service interface to resolve a name (`#1410 <https://github.com/ros2/rclcpp/issues/1410>`_)
+* Update deprecated gtest macros (`#1370 <https://github.com/ros2/rclcpp/issues/1370>`_)
+* Clear members for StaticExecutorEntitiesCollector to avoid shared_ptr dependency (`#1303 <https://github.com/ros2/rclcpp/issues/1303>`_)
+* Increase test timeouts of slow running tests with rmw_connext_cpp (`#1400 <https://github.com/ros2/rclcpp/issues/1400>`_)
+* Avoid self dependency that not destoryed (`#1301 <https://github.com/ros2/rclcpp/issues/1301>`_)
+* Update maintainers (`#1384 <https://github.com/ros2/rclcpp/issues/1384>`_)
+* Add clock qos to node options (`#1375 <https://github.com/ros2/rclcpp/issues/1375>`_)
+* Fix NodeOptions copy constructor (`#1376 <https://github.com/ros2/rclcpp/issues/1376>`_)
+* Make sure to clean the external client/service handle. (`#1296 <https://github.com/ros2/rclcpp/issues/1296>`_)
+* Increase coverage of WaitSetTemplate (`#1368 <https://github.com/ros2/rclcpp/issues/1368>`_)
+* Increase coverage of guard_condition.cpp to 100% (`#1369 <https://github.com/ros2/rclcpp/issues/1369>`_)
+* Add coverage statement (`#1367 <https://github.com/ros2/rclcpp/issues/1367>`_)
+* Tests for LoanedMessage with mocked loaned message publisher (`#1366 <https://github.com/ros2/rclcpp/issues/1366>`_)
+* Add unit tests for qos and qos_event files (`#1352 <https://github.com/ros2/rclcpp/issues/1352>`_)
+* Finish coverage of publisher API (`#1365 <https://github.com/ros2/rclcpp/issues/1365>`_)
+* Finish API coverage on executors. (`#1364 <https://github.com/ros2/rclcpp/issues/1364>`_)
+* Add test for ParameterService (`#1355 <https://github.com/ros2/rclcpp/issues/1355>`_)
+* Add time API coverage tests (`#1347 <https://github.com/ros2/rclcpp/issues/1347>`_)
+* Add timer coverage tests (`#1363 <https://github.com/ros2/rclcpp/issues/1363>`_)
+* Add in additional tests for parameter_client.cpp coverage.
+* Minor fixes to the parameter_service.cpp file.
+* reset rcl_context shared_ptr after calling rcl_init sucessfully (`#1357 <https://github.com/ros2/rclcpp/issues/1357>`_)
+* Improved test publisher - zero qos history depth value exception (`#1360 <https://github.com/ros2/rclcpp/issues/1360>`_)
+* Covered resolve_use_intra_process (`#1359 <https://github.com/ros2/rclcpp/issues/1359>`_)
+* Improve test_subscription_options (`#1358 <https://github.com/ros2/rclcpp/issues/1358>`_)
+* Add in more tests for init_options coverage. (`#1353 <https://github.com/ros2/rclcpp/issues/1353>`_)
+* Test the remaining node public API (`#1342 <https://github.com/ros2/rclcpp/issues/1342>`_)
+* Complete coverage of Parameter and ParameterValue API (`#1344 <https://github.com/ros2/rclcpp/issues/1344>`_)
+* Add in more tests for the utilities. (`#1349 <https://github.com/ros2/rclcpp/issues/1349>`_)
+* Add in two more tests for expand_topic_or_service_name. (`#1350 <https://github.com/ros2/rclcpp/issues/1350>`_)
+* Add tests for node_options API (`#1343 <https://github.com/ros2/rclcpp/issues/1343>`_)
+* Add in more coverage for expand_topic_or_service_name. (`#1346 <https://github.com/ros2/rclcpp/issues/1346>`_)
+* Test exception in spin_until_future_complete. (`#1345 <https://github.com/ros2/rclcpp/issues/1345>`_)
+* Add coverage tests graph_listener (`#1330 <https://github.com/ros2/rclcpp/issues/1330>`_)
+* Add in unit tests for the Executor class.
+* Allow mimick patching of methods with up to 9 arguments.
+* Improve the error messages in the Executor class.
+* Add coverage for client API (`#1329 <https://github.com/ros2/rclcpp/issues/1329>`_)
+* Increase service coverage (`#1332 <https://github.com/ros2/rclcpp/issues/1332>`_)
+* Make more of the static entity collector API private.
+* Const-ify more of the static executor.
+* Add more tests for the static single threaded executor.
+* Many more tests for the static_executor_entities_collector.
+* Get one more line of code coverage in memory_strategy.cpp
+* Bugfix when adding callback group.
+* Fix typos in comments.
+* Remove deprecated executor::FutureReturnCode APIs. (`#1327 <https://github.com/ros2/rclcpp/issues/1327>`_)
+* Increase coverage of publisher/subscription API (`#1325 <https://github.com/ros2/rclcpp/issues/1325>`_)
+* Not finalize guard condition while destructing SubscriptionIntraProcess (`#1307 <https://github.com/ros2/rclcpp/issues/1307>`_)
+* Expose qos setting for /rosout (`#1247 <https://github.com/ros2/rclcpp/issues/1247>`_)
+* Add coverage for missing API (except executors) (`#1326 <https://github.com/ros2/rclcpp/issues/1326>`_)
+* Include topic name in QoS mismatch warning messages (`#1286 <https://github.com/ros2/rclcpp/issues/1286>`_)
+* Add coverage tests context functions (`#1321 <https://github.com/ros2/rclcpp/issues/1321>`_)
+* Increase coverage of node_interfaces, including with mocking rcl errors (`#1322 <https://github.com/ros2/rclcpp/issues/1322>`_)
+* Contributors: Ada-King, Alejandro Hernández Cordero, Audrow Nash, Barry Xu, Chen Lihui, Chris Lalancette, Christophe Bedard, Ivan Santiago Paunovic, Jorge Perez, Morgan Quigley, brawner
+
+5.0.0 (2020-09-18)
+------------------
+* Make node_graph::count_graph_users() const (`#1320 <https://github.com/ros2/rclcpp/issues/1320>`_)
+* Add coverage for wait_set_policies (`#1316 <https://github.com/ros2/rclcpp/issues/1316>`_)
+* Only exchange intra_process waitable if nonnull (`#1317 <https://github.com/ros2/rclcpp/issues/1317>`_)
+* Check waitable for nullptr during constructor (`#1315 <https://github.com/ros2/rclcpp/issues/1315>`_)
+* Call vector.erase with end iterator overload (`#1314 <https://github.com/ros2/rclcpp/issues/1314>`_)
+* Use best effort, keep last, history depth 1 QoS Profile for '/clock' subscriptions (`#1312 <https://github.com/ros2/rclcpp/issues/1312>`_)
+* Add tests type_support module (`#1308 <https://github.com/ros2/rclcpp/issues/1308>`_)
+* Replace std_msgs with test_msgs in executors test (`#1310 <https://github.com/ros2/rclcpp/issues/1310>`_)
+* Add set_level for rclcpp::Logger (`#1284 <https://github.com/ros2/rclcpp/issues/1284>`_)
+* Remove unused private function (rclcpp::Node and rclcpp_lifecycle::Node) (`#1294 <https://github.com/ros2/rclcpp/issues/1294>`_)
+* Adding tests basic getters (`#1291 <https://github.com/ros2/rclcpp/issues/1291>`_)
+* Adding callback groups in executor (`#1218 <https://github.com/ros2/rclcpp/issues/1218>`_)
+* Refactor Subscription Topic Statistics Tests (`#1281 <https://github.com/ros2/rclcpp/issues/1281>`_)
+* Add operator!= for duration (`#1236 <https://github.com/ros2/rclcpp/issues/1236>`_)
+* Fix clock thread issue (`#1266 <https://github.com/ros2/rclcpp/issues/1266>`_) (`#1267 <https://github.com/ros2/rclcpp/issues/1267>`_)
+* Fix topic stats test, wait for more messages, only check the ones with samples (`#1274 <https://github.com/ros2/rclcpp/issues/1274>`_)
+* Add get_domain_id method to rclcpp::Context (`#1271 <https://github.com/ros2/rclcpp/issues/1271>`_)
+* Fixes for unit tests that fail under cyclonedds (`#1270 <https://github.com/ros2/rclcpp/issues/1270>`_)
+* initialize_logging\_ should be copied (`#1272 <https://github.com/ros2/rclcpp/issues/1272>`_)
+* Use static_cast instead of C-style cast for instrumentation (`#1263 <https://github.com/ros2/rclcpp/issues/1263>`_)
+* Make parameter clients use template constructors (`#1249 <https://github.com/ros2/rclcpp/issues/1249>`_)
+* Ability to configure domain_id via InitOptions. (`#1165 <https://github.com/ros2/rclcpp/issues/1165>`_)
+* Simplify and fix allocator memory strategy unit test for connext (`#1252 <https://github.com/ros2/rclcpp/issues/1252>`_)
+* Use global namespace for parameter events subscription topic (`#1257 <https://github.com/ros2/rclcpp/issues/1257>`_)
+* Increase timeouts for connext for long tests (`#1253 <https://github.com/ros2/rclcpp/issues/1253>`_)
+* Adjust test_static_executor_entities_collector for rmw_connext_cpp (`#1251 <https://github.com/ros2/rclcpp/issues/1251>`_)
+* Fix failing test with Connext since it doesn't wait for discovery (`#1246 <https://github.com/ros2/rclcpp/issues/1246>`_)
+* Fix node graph test with Connext and CycloneDDS returning actual data (`#1245 <https://github.com/ros2/rclcpp/issues/1245>`_)
+* Warn about unused result of add_on_set_parameters_callback (`#1238 <https://github.com/ros2/rclcpp/issues/1238>`_)
+* Unittests for memory strategy files, except allocator_memory_strategy (`#1189 <https://github.com/ros2/rclcpp/issues/1189>`_)
+* EXPECT_THROW_EQ and ASSERT_THROW_EQ macros for unittests (`#1232 <https://github.com/ros2/rclcpp/issues/1232>`_)
+* Add unit test for static_executor_entities_collector (`#1221 <https://github.com/ros2/rclcpp/issues/1221>`_)
+* Parameterize test executors for all executor types (`#1222 <https://github.com/ros2/rclcpp/issues/1222>`_)
+* Unit tests for allocator_memory_strategy.cpp part 2 (`#1198 <https://github.com/ros2/rclcpp/issues/1198>`_)
+* Unit tests for allocator_memory_strategy.hpp (`#1197 <https://github.com/ros2/rclcpp/issues/1197>`_)
+* Derive and throw exception in spin_some spin_all for StaticSingleThreadedExecutor (`#1220 <https://github.com/ros2/rclcpp/issues/1220>`_)
+* Make ring buffer thread-safe (`#1213 <https://github.com/ros2/rclcpp/issues/1213>`_)
+* Add missing RCLCPP_PUBLIC to ~StaticExecutorEntitiesCollector (`#1227 <https://github.com/ros2/rclcpp/issues/1227>`_)
+* Document graph functions don't apply remap rules (`#1225 <https://github.com/ros2/rclcpp/issues/1225>`_)
+* Remove recreation of entities_collector (`#1217 <https://github.com/ros2/rclcpp/issues/1217>`_)
+* Contributors: Audrow Nash, Chen Lihui, Christophe Bedard, Daisuke Sato, Devin Bonnie, Dirk Thomas, Ivan Santiago Paunovic, Jacob Perron, Jannik Abbenseth, Jorge Perez, Pedro Pena, Shane Loretz, Stephen Brawner, Tomoya Fujita
+
+4.0.0 (2020-07-09)
+------------------
+* Fix rclcpp::NodeOptions::operator= (`#1211 <https://github.com/ros2/rclcpp/issues/1211>`_)
+* Link against thread library where necessary (`#1210 <https://github.com/ros2/rclcpp/issues/1210>`_)
+* Unit tests for node interfaces (`#1202 <https://github.com/ros2/rclcpp/issues/1202>`_)
+* Remove usage of domain id in node options (`#1205 <https://github.com/ros2/rclcpp/issues/1205>`_)
+* Remove deprecated set_on_parameters_set_callback function (`#1199 <https://github.com/ros2/rclcpp/issues/1199>`_)
+* Fix conversion of negative durations to messages (`#1188 <https://github.com/ros2/rclcpp/issues/1188>`_)
+* Fix implementation of NodeOptions::use_global_arguments() (`#1176 <https://github.com/ros2/rclcpp/issues/1176>`_)
+* Bump to QD to level 3 and fixed links (`#1158 <https://github.com/ros2/rclcpp/issues/1158>`_)
+* Fix pub/sub count API tests (`#1203 <https://github.com/ros2/rclcpp/issues/1203>`_)
+* Update tracetools' QL to 2 in rclcpp's QD (`#1187 <https://github.com/ros2/rclcpp/issues/1187>`_)
+* Fix exception message on rcl_clock_init (`#1182 <https://github.com/ros2/rclcpp/issues/1182>`_)
+* Throw exception if rcl_timer_init fails (`#1179 <https://github.com/ros2/rclcpp/issues/1179>`_)
+* Unit tests for some header-only functions/classes (`#1181 <https://github.com/ros2/rclcpp/issues/1181>`_)
+* Callback should be perfectly-forwarded (`#1183 <https://github.com/ros2/rclcpp/issues/1183>`_)
+* Add unit tests for logging functionality (`#1184 <https://github.com/ros2/rclcpp/issues/1184>`_)
+* Add create_publisher include to create_subscription (`#1180 <https://github.com/ros2/rclcpp/issues/1180>`_)
+* Contributors: Alejandro Hernández Cordero, Christophe Bedard, Claire Wang, Dirk Thomas, Ivan Santiago Paunovic, Johannes Meyer, Michel Hidalgo, Stephen Brawner, tomoya
+
+3.0.0 (2020-06-18)
+------------------
+* Check period duration in create_wall_timer (`#1178 <https://github.com/ros2/rclcpp/issues/1178>`_)
+* Fix get_node_time_source_interface() docstring (`#988 <https://github.com/ros2/rclcpp/issues/988>`_)
+* Add message lost subscription event (`#1164 <https://github.com/ros2/rclcpp/issues/1164>`_)
+* Add spin_all method to Executor (`#1156 <https://github.com/ros2/rclcpp/issues/1156>`_)
+* Reorganize test directory and split CMakeLists.txt (`#1173 <https://github.com/ros2/rclcpp/issues/1173>`_)
+* Check if context is valid when looping in spin_some (`#1167 <https://github.com/ros2/rclcpp/issues/1167>`_)
+* Add check for invalid topic statistics publish period (`#1151 <https://github.com/ros2/rclcpp/issues/1151>`_)
+* Fix spin_until_future_complete: check spinning value (`#1023 <https://github.com/ros2/rclcpp/issues/1023>`_)
+* Fix doxygen warnings (`#1163 <https://github.com/ros2/rclcpp/issues/1163>`_)
+* Fix reference to rclcpp in its Quality declaration (`#1161 <https://github.com/ros2/rclcpp/issues/1161>`_)
+* Allow spin_until_future_complete to accept any future like object (`#1113 <https://github.com/ros2/rclcpp/issues/1113>`_)
+* Contributors: Alejandro Hernández Cordero, Christophe Bedard, Devin Bonnie, Dirk Thomas, DongheeYe, Ivan Santiago Paunovic, Jacob Perron, Sarthak Mittal, brawner, tomoya
+
+2.0.0 (2020-06-01)
+------------------
+* Added missing virtual destructors. (`#1149 <https://github.com/ros2/rclcpp/issues/1149>`_)
+* Fixed a test which was using different types on the same topic. (`#1150 <https://github.com/ros2/rclcpp/issues/1150>`_)
+* Made ``test_rate`` more reliable on Windows and improve error output when it fails (`#1146 <https://github.com/ros2/rclcpp/issues/1146>`_)
+* Added Security Vulnerability Policy pointing to REP-2006. (`#1130 <https://github.com/ros2/rclcpp/issues/1130>`_)
+* Added missing header in ``logging_mutex.cpp``. (`#1145 <https://github.com/ros2/rclcpp/issues/1145>`_)
+* Changed the WaitSet API to pass a shared pointer by value instead than by const reference when possible. (`#1141 <https://github.com/ros2/rclcpp/issues/1141>`_)
+* Changed ``SubscriptionBase::get_subscription_handle() const`` to return a shared pointer to const value. (`#1140 <https://github.com/ros2/rclcpp/issues/1140>`_)
+* Extended the lifetime of ``rcl_publisher_t`` by holding onto the shared pointer in order to avoid a use after free situation. (`#1119 <https://github.com/ros2/rclcpp/issues/1119>`_)
+* Improved some docblocks (`#1127 <https://github.com/ros2/rclcpp/issues/1127>`_)
+* Fixed a lock-order-inversion (potential deadlock) (`#1135 <https://github.com/ros2/rclcpp/issues/1135>`_)
+* Fixed a potential Construction/Destruction order problem between global contexts vector and Context of static lifetime (`#1132 <https://github.com/ros2/rclcpp/issues/1132>`_)
+* Contributors: Alejandro Hernández Cordero, Chris Lalancette, Ivan Santiago Paunovic, Michel Hidalgo, tomoya
+
+1.1.0 (2020-05-26)
+------------------
+* Deprecate set_on_parameters_set_callback (`#1123 <https://github.com/ros2/rclcpp/issues/1123>`_)
+* Expose get_service_names_and_types_by_node from rcl in rclcpp (`#1131 <https://github.com/ros2/rclcpp/issues/1131>`_)
+* Fix thread safety issues related to logging (`#1125 <https://github.com/ros2/rclcpp/issues/1125>`_)
+* Make sure rmw_publisher_options is initialized in to_rcl_publisher_options (`#1099 <https://github.com/ros2/rclcpp/issues/1099>`_)
+* Remove empty lines within method signatures (`#1128 <https://github.com/ros2/rclcpp/issues/1128>`_)
+* Add API review March 2020 document (`#1031 <https://github.com/ros2/rclcpp/issues/1031>`_)
+* Improve documentation (`#1106 <https://github.com/ros2/rclcpp/issues/1106>`_)
+* Make test multi threaded executor more reliable (`#1105 <https://github.com/ros2/rclcpp/issues/1105>`_)
+* Fixed rep links and added more details to dependencies in quality declaration (`#1116 <https://github.com/ros2/rclcpp/issues/1116>`_)
+* Update quality declarations to reflect version 1.0 (`#1115 <https://github.com/ros2/rclcpp/issues/1115>`_)
+* Contributors: Alejandro Hernández Cordero, ChenYing Kuo, Claire Wang, Dirk Thomas, Ivan Santiago Paunovic, William Woodall, Stephen Brawner
+
+1.0.0 (2020-05-12)
+------------------
+* Remove MANUAL_BY_NODE liveliness API (`#1107 <https://github.com/ros2/rclcpp/issues/1107>`_)
+* Use rosidl_default_generators dependency in test (`#1114 <https://github.com/ros2/rclcpp/issues/1114>`_)
+* Make sure to include what you use (`#1112 <https://github.com/ros2/rclcpp/issues/1112>`_)
+* Mark flaky test with xfail: TestMultiThreadedExecutor (`#1109 <https://github.com/ros2/rclcpp/issues/1109>`_)
+* Contributors: Chris Lalancette, Ivan Santiago Paunovic, Karsten Knese, Louise Poubel
+
+0.9.1 (2020-05-08)
+------------------
+* Fix tests that were not properly torn down (`#1073 <https://github.com/ros2/rclcpp/issues/1073>`_)
+* Added docblock in rclcpp (`#1103 <https://github.com/ros2/rclcpp/issues/1103>`_)
+* Added Quality declaration: rclcpp, rclpp_action, rclcpp_components andrclcpp_lifecycle (`#1100 <https://github.com/ros2/rclcpp/issues/1100>`_)
+* Use RCL_RET_SERVICE_TAKE_FAILED and not RCL_RET_CLIENT_TAKE_FAILED when checking a request take (`#1101 <https://github.com/ros2/rclcpp/issues/1101>`_)
+* Update comment about return value in Executor::get_next_ready_executable (`#1085 <https://github.com/ros2/rclcpp/issues/1085>`_)
+* Contributors: Alejandro Hernández Cordero, Christophe Bedard, Devin Bonnie, Ivan Santiago Paunovic
+
+0.9.0 (2020-04-29)
+------------------
+* Serialized message move constructor (`#1097 <https://github.com/ros2/rclcpp/issues/1097>`_)
+* Enforce a precedence for wildcard matching in parameter overrides. (`#1094 <https://github.com/ros2/rclcpp/issues/1094>`_)
+* Add serialized_message.hpp header (`#1095 <https://github.com/ros2/rclcpp/issues/1095>`_)
+* Add received message age metric to topic statistics (`#1080 <https://github.com/ros2/rclcpp/issues/1080>`_)
+* Deprecate redundant namespaces (`#1083 <https://github.com/ros2/rclcpp/issues/1083>`_)
+* Export targets in addition to include directories / libraries (`#1088 <https://github.com/ros2/rclcpp/issues/1088>`_)
+* Ensure logging is initialized just once (`#998 <https://github.com/ros2/rclcpp/issues/998>`_)
+* Adapt subscription traits to rclcpp::SerializedMessage (`#1092 <https://github.com/ros2/rclcpp/issues/1092>`_)
+* Protect subscriber_statistics_collectors\_ with a mutex (`#1084 <https://github.com/ros2/rclcpp/issues/1084>`_)
+* Remove unused test variable (`#1087 <https://github.com/ros2/rclcpp/issues/1087>`_)
+* Use serialized message (`#1081 <https://github.com/ros2/rclcpp/issues/1081>`_)
+* Integrate topic statistics (`#1072 <https://github.com/ros2/rclcpp/issues/1072>`_)
+* Fix rclcpp interface traits test (`#1086 <https://github.com/ros2/rclcpp/issues/1086>`_)
+* Generate node interfaces' getters and traits (`#1069 <https://github.com/ros2/rclcpp/issues/1069>`_)
+* Use composition for serialized message (`#1082 <https://github.com/ros2/rclcpp/issues/1082>`_)
+* Dnae adas/serialized message (`#1075 <https://github.com/ros2/rclcpp/issues/1075>`_)
+* Reflect changes in rclcpp API (`#1079 <https://github.com/ros2/rclcpp/issues/1079>`_)
+* Fix build regression (`#1078 <https://github.com/ros2/rclcpp/issues/1078>`_)
+* Add NodeDefault option for enabling topic statistics (`#1074 <https://github.com/ros2/rclcpp/issues/1074>`_)
+* Topic Statistics: Add SubscriptionTopicStatistics class (`#1050 <https://github.com/ros2/rclcpp/issues/1050>`_)
+* Add SubscriptionOptions for topic statistics (`#1057 <https://github.com/ros2/rclcpp/issues/1057>`_)
+* Remove warning message from failing to register default callback (`#1067 <https://github.com/ros2/rclcpp/issues/1067>`_)
+* Create a default warning for qos incompatibility (`#1051 <https://github.com/ros2/rclcpp/issues/1051>`_)
+* Add WaitSet class and modify entities to work without executor (`#1047 <https://github.com/ros2/rclcpp/issues/1047>`_)
+* Include what you use (`#1059 <https://github.com/ros2/rclcpp/issues/1059>`_)
+* Rename rosidl_generator_cpp namespace to rosidl_runtime_cpp (`#1060 <https://github.com/ros2/rclcpp/issues/1060>`_)
+* Changed rosidl_generator_c/cpp to rosidl_runtime_c/cpp (`#1014 <https://github.com/ros2/rclcpp/issues/1014>`_)
+* Use constexpr for endpoint type name (`#1055 <https://github.com/ros2/rclcpp/issues/1055>`_)
+* Add InvalidParameterTypeException (`#1027 <https://github.com/ros2/rclcpp/issues/1027>`_)
+* Support for ON_REQUESTED_INCOMPATIBLE_QOS and ON_OFFERED_INCOMPATIBLE_QOS events (`#924 <https://github.com/ros2/rclcpp/issues/924>`_)
+* Fixup clang warning (`#1040 <https://github.com/ros2/rclcpp/issues/1040>`_)
+* Adding a "static" single threaded executor (`#1034 <https://github.com/ros2/rclcpp/issues/1034>`_)
+* Add equality operators for QoS profile (`#1032 <https://github.com/ros2/rclcpp/issues/1032>`_)
+* Remove extra vertical whitespace (`#1030 <https://github.com/ros2/rclcpp/issues/1030>`_)
+* Switch IntraProcessMessage to test_msgs/Empty (`#1017 <https://github.com/ros2/rclcpp/issues/1017>`_)
+* Add new type of exception that may be thrown during creation of publisher/subscription (`#1026 <https://github.com/ros2/rclcpp/issues/1026>`_)
+* Don't check lifespan on publisher QoS (`#1002 <https://github.com/ros2/rclcpp/issues/1002>`_)
+* Fix get_parameter_tyeps of AsyncPrameterClient results are always empty (`#1019 <https://github.com/ros2/rclcpp/issues/1019>`_)
+* Cleanup node interfaces includes (`#1016 <https://github.com/ros2/rclcpp/issues/1016>`_)
+* Add ifdefs to remove tracing-related calls if tracing is disabled (`#1001 <https://github.com/ros2/rclcpp/issues/1001>`_)
+* Include missing header in node_graph.cpp (`#994 <https://github.com/ros2/rclcpp/issues/994>`_)
+* Add missing includes of logging.hpp (`#995 <https://github.com/ros2/rclcpp/issues/995>`_)
+* Zero initialize publisher GID in subscription intra process callback (`#1011 <https://github.com/ros2/rclcpp/issues/1011>`_)
+* Removed ament_cmake dependency (`#989 <https://github.com/ros2/rclcpp/issues/989>`_)
+* Switch to using new rcutils_strerror (`#993 <https://github.com/ros2/rclcpp/issues/993>`_)
+* Ensure all rclcpp::Clock accesses are thread-safe
+* Use a PIMPL for rclcpp::Clock implementation
+* Replace rmw_implementation for rmw dependency in package.xml (`#990 <https://github.com/ros2/rclcpp/issues/990>`_)
+* Add missing service callback registration tracepoint (`#986 <https://github.com/ros2/rclcpp/issues/986>`_)
+* Rename rmw_topic_endpoint_info_array count to size (`#996 <https://github.com/ros2/rclcpp/issues/996>`_)
+* Implement functions to get publisher and subcription informations like QoS policies from topic name (`#960 <https://github.com/ros2/rclcpp/issues/960>`_)
+* Code style only: wrap after open parenthesis if not in one line (`#977 <https://github.com/ros2/rclcpp/issues/977>`_)
+* Accept taking an rvalue ref future in spin_until_future_complete (`#971 <https://github.com/ros2/rclcpp/issues/971>`_)
+* Allow node clock use in logging macros (`#969 <https://github.com/ros2/rclcpp/issues/969>`_) (`#970 <https://github.com/ros2/rclcpp/issues/970>`_)
+* Change order of deprecated and visibility attributes (`#968 <https://github.com/ros2/rclcpp/issues/968>`_)
+* Deprecated is_initialized() (`#967 <https://github.com/ros2/rclcpp/issues/967>`_)
+* Don't specify calling convention in std::_Binder template (`#952 <https://github.com/ros2/rclcpp/issues/952>`_)
+* Added missing include to logging.hpp (`#964 <https://github.com/ros2/rclcpp/issues/964>`_)
+* Assigning make_shared result to variables in test (`#963 <https://github.com/ros2/rclcpp/issues/963>`_)
+* Fix unused parameter warning (`#962 <https://github.com/ros2/rclcpp/issues/962>`_)
+* Stop retaining ownership of the rcl context in GraphListener (`#946 <https://github.com/ros2/rclcpp/issues/946>`_)
+* Clear sub contexts when starting another init-shutdown cycle (`#947 <https://github.com/ros2/rclcpp/issues/947>`_)
+* Avoid possible UB in Clock jump callbacks (`#954 <https://github.com/ros2/rclcpp/issues/954>`_)
+* Handle unknown global ROS arguments (`#951 <https://github.com/ros2/rclcpp/issues/951>`_)
+* Mark get_clock() as override to fix clang warnings (`#939 <https://github.com/ros2/rclcpp/issues/939>`_)
+* Create node clock calls const (try 2) (`#922 <https://github.com/ros2/rclcpp/issues/922>`_)
+* Fix asserts on shared_ptr::use_count; expects long, got uint32 (`#936 <https://github.com/ros2/rclcpp/issues/936>`_)
+* Use absolute topic name for parameter events (`#929 <https://github.com/ros2/rclcpp/issues/929>`_)
+* Add enable_rosout into NodeOptions. (`#900 <https://github.com/ros2/rclcpp/issues/900>`_)
+* Removing "virtual", adding "override" keywords (`#897 <https://github.com/ros2/rclcpp/issues/897>`_)
+* Use weak_ptr to store context in GraphListener (`#906 <https://github.com/ros2/rclcpp/issues/906>`_)
+* Complete published event message when declaring a parameter (`#928 <https://github.com/ros2/rclcpp/issues/928>`_)
+* Fix duration.cpp lint error (`#930 <https://github.com/ros2/rclcpp/issues/930>`_)
+* Intra-process subscriber should use RMW actual qos. (ros2`#913 <https://github.com/ros2/rclcpp/issues/913>`_) (`#914 <https://github.com/ros2/rclcpp/issues/914>`_)
+* Type conversions fixes (`#901 <https://github.com/ros2/rclcpp/issues/901>`_)
+* Add override keyword to functions
+* Remove unnecessary virtual keywords
+* Only check for new work once in spin_some (`#471 <https://github.com/ros2/rclcpp/issues/471>`_) (`#844 <https://github.com/ros2/rclcpp/issues/844>`_)
+* Add addition/subtraction assignment operators to Time (`#748 <https://github.com/ros2/rclcpp/issues/748>`_)
+* Contributors: Alberto Soragna, Alejandro Hernández Cordero, Barry Xu, Chris Lalancette, Christophe Bedard, Claire Wang, Dan Rose, DensoADAS, Devin Bonnie, Dino Hüllmann, Dirk Thomas, DongheeYe, Emerson Knapp, Ivan Santiago Paunovic, Jacob Perron, Jaison Titus, Karsten Knese, Matt Schickler, Miaofei Mei, Michel Hidalgo, Mikael Arguedas, Monika Idzik, Prajakta Gokhale, Roger Strain, Scott K Logan, Sean Kelly, Stephen Brawner, Steven Macenski, Steven! Ragnarök, Todd Malsbary, Tomoya Fujita, William Woodall, Zachary Michaels
+
 0.8.3 (2019-11-19)
 ------------------
 

rclcpp/CMakeLists.txt

@@ -1,8 +1,11 @@
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.12)
 
 project(rclcpp)
 
+find_package(Threads REQUIRED)
+
 find_package(ament_cmake_ros REQUIRED)
+find_package(ament_index_cpp REQUIRED)
 find_package(builtin_interfaces REQUIRED)
 find_package(libstatistics_collector REQUIRED)
 find_package(rcl REQUIRED)
@@ -18,16 +21,19 @@ find_package(rosidl_typesupport_cpp REQUIRED)
 find_package(statistics_msgs REQUIRED)
 find_package(tracetools REQUIRED)
 
-# Default to C++14
+# TODO(wjwwood): remove this when gtest can build on its own, when using target_compile_features()
+# Default to C++17
 if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 14)
+  set(CMAKE_CXX_STANDARD 17)
 endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-  add_compile_options(-Wall -Wextra -Wpedantic)
+  # About -Wno-sign-conversion: With Clang, -Wconversion implies -Wsign-conversion. There are a number of
+  # implicit sign conversions in rclcpp and gtest.cc, see https://ci.ros2.org/job/ci_osx/9265/.
+  # Hence disabling -Wsign-conversion for now until all those have eventually been fixed.
+  # (from https://github.com/ros2/rclcpp/pull/1188#issuecomment-650229140)
+  add_compile_options(-Wall -Wextra -Wconversion -Wno-sign-conversion -Wpedantic -Wnon-virtual-dtor -Woverloaded-virtual)
 endif()
 
-include_directories(include)
-
 set(${PROJECT_NAME}_SRCS
   src/rclcpp/any_executable.cpp
   src/rclcpp/callback_group.cpp
@@ -35,6 +41,8 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/clock.cpp
   src/rclcpp/context.cpp
   src/rclcpp/contexts/default_context.cpp
+  src/rclcpp/detail/add_guard_condition_to_rcl_wait_set.cpp
+  src/rclcpp/detail/resolve_parameter_overrides.cpp
   src/rclcpp/detail/rmw_implementation_specific_payload.cpp
   src/rclcpp/detail/rmw_implementation_specific_publisher_payload.cpp
   src/rclcpp/detail/rmw_implementation_specific_subscription_payload.cpp
@@ -45,22 +53,25 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/executable_list.cpp
   src/rclcpp/executor.cpp
   src/rclcpp/executors.cpp
-  src/rclcpp/expand_topic_or_service_name.cpp
   src/rclcpp/executors/multi_threaded_executor.cpp
   src/rclcpp/executors/single_threaded_executor.cpp
   src/rclcpp/executors/static_executor_entities_collector.cpp
   src/rclcpp/executors/static_single_threaded_executor.cpp
+  src/rclcpp/expand_topic_or_service_name.cpp
   src/rclcpp/future_return_code.cpp
+  src/rclcpp/generic_publisher.cpp
+  src/rclcpp/generic_subscription.cpp
   src/rclcpp/graph_listener.cpp
   src/rclcpp/guard_condition.cpp
   src/rclcpp/init_options.cpp
   src/rclcpp/intra_process_manager.cpp
   src/rclcpp/logger.cpp
+  src/rclcpp/logging_mutex.cpp
   src/rclcpp/memory_strategies.cpp
   src/rclcpp/memory_strategy.cpp
   src/rclcpp/message_info.cpp
+  src/rclcpp/network_flow_endpoint.cpp
   src/rclcpp/node.cpp
-  src/rclcpp/node_options.cpp
   src/rclcpp/node_interfaces/node_base.cpp
   src/rclcpp/node_interfaces/node_clock.cpp
   src/rclcpp/node_interfaces/node_graph.cpp
@@ -71,15 +82,18 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/node_interfaces/node_timers.cpp
   src/rclcpp/node_interfaces/node_topics.cpp
   src/rclcpp/node_interfaces/node_waitables.cpp
+  src/rclcpp/node_options.cpp
   src/rclcpp/parameter.cpp
-  src/rclcpp/parameter_value.cpp
   src/rclcpp/parameter_client.cpp
+  src/rclcpp/parameter_event_handler.cpp
   src/rclcpp/parameter_events_filter.cpp
   src/rclcpp/parameter_map.cpp
   src/rclcpp/parameter_service.cpp
+  src/rclcpp/parameter_value.cpp
   src/rclcpp/publisher_base.cpp
   src/rclcpp/qos.cpp
   src/rclcpp/qos_event.cpp
+  src/rclcpp/qos_overriding_options.cpp
   src/rclcpp/serialization.cpp
   src/rclcpp/serialized_message.cpp
   src/rclcpp/service.cpp
@@ -90,11 +104,14 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/time_source.cpp
   src/rclcpp/timer.cpp
   src/rclcpp/type_support.cpp
+  src/rclcpp/typesupport_helpers.cpp
   src/rclcpp/utilities.cpp
   src/rclcpp/wait_set_policies/detail/write_preferring_read_write_lock.cpp
   src/rclcpp/waitable.cpp
 )
 
+find_package(Python3 REQUIRED COMPONENTS Interpreter)
+
 # "watch" template for changes
 configure_file(
   "resource/logging.hpp.em"
@@ -102,27 +119,82 @@ configure_file(
   COPYONLY
 )
 # generate header with logging macros
-set(python_code
+set(python_code_logging
   "import em"
   "em.invoke(['-o', 'include/rclcpp/logging.hpp', '${CMAKE_CURRENT_SOURCE_DIR}/resource/logging.hpp.em'])")
-string(REPLACE ";" "$<SEMICOLON>" python_code "${python_code}")
+string(REPLACE ";" "$<SEMICOLON>" python_code_logging "${python_code_logging}")
 add_custom_command(OUTPUT include/rclcpp/logging.hpp
   COMMAND ${CMAKE_COMMAND} -E make_directory "include/rclcpp"
-  COMMAND ${PYTHON_EXECUTABLE} ARGS -c "${python_code}"
+  COMMAND Python3::Interpreter ARGS -c "${python_code_logging}"
   DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/logging.hpp.em.watch"
   COMMENT "Expanding logging.hpp.em"
   VERBATIM
 )
 list(APPEND ${PROJECT_NAME}_SRCS
   include/rclcpp/logging.hpp)
-include_directories("${CMAKE_CURRENT_BINARY_DIR}/include")
 
-add_library(${PROJECT_NAME}
-  ${${PROJECT_NAME}_SRCS})
+file(GLOB interface_files "include/rclcpp/node_interfaces/node_*_interface.hpp")
+foreach(interface_file ${interface_files})
+  get_filename_component(interface_name ${interface_file} NAME_WE)
+
+  # "watch" template for changes
+  configure_file(
+    "resource/interface_traits.hpp.em"
+    "${CMAKE_CURRENT_BINARY_DIR}/${interface_name}_traits.hpp.em.watch"
+    COPYONLY
+  )
+  set(python_${interface_name}_traits
+    "import em"
+    "em.invoke(['-D', 'interface_name = \\'${interface_name}\\'', '-o', 'include/rclcpp/node_interfaces/${interface_name}_traits.hpp', '${CMAKE_CURRENT_SOURCE_DIR}/resource/interface_traits.hpp.em'])")
+  string(REPLACE ";" "$<SEMICOLON>" python_${interface_name}_traits "${python_${interface_name}_traits}")
+  add_custom_command(OUTPUT include/rclcpp/node_interfaces/${interface_name}_traits.hpp
+    COMMAND ${CMAKE_COMMAND} -E make_directory "include/rclcpp/node_interfaces"
+    COMMAND Python3::Interpreter ARGS -c "${python_${interface_name}_traits}"
+    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/${interface_name}_traits.hpp.em.watch"
+    COMMENT "Expanding interface_traits.hpp.em into ${interface_name}_traits.hpp"
+    VERBATIM
+  )
+  list(APPEND ${PROJECT_NAME}_SRCS
+    include/rclcpp/node_interfaces/${interface_name}_traits.hpp)
+
+  # "watch" template for changes
+  configure_file(
+    "resource/get_interface.hpp.em"
+    "get_${interface_name}.hpp.em.watch"
+    COPYONLY
+  )
+  set(python_get_${interface_name}
+    "import em"
+    "em.invoke(['-D', 'interface_name = \\'${interface_name}\\'', '-o', 'include/rclcpp/node_interfaces/get_${interface_name}.hpp', '${CMAKE_CURRENT_SOURCE_DIR}/resource/get_interface.hpp.em'])")
+  string(REPLACE ";" "$<SEMICOLON>" python_get_${interface_name} "${python_get_${interface_name}}")
+  add_custom_command(OUTPUT include/rclcpp/node_interfaces/get_${interface_name}.hpp
+    COMMAND ${CMAKE_COMMAND} -E make_directory "include/rclcpp/node_interfaces"
+    COMMAND Python3::Interpreter ARGS -c "${python_get_${interface_name}}"
+    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/get_${interface_name}.hpp.em.watch"
+    COMMENT "Expanding get_interface.hpp.em into get_${interface_file}.hpp"
+    VERBATIM
+  )
+  list(APPEND ${PROJECT_NAME}_SRCS
+    include/rclcpp/node_interfaces/get_${interface_name}.hpp)
+endforeach()
+
+add_library(${PROJECT_NAME} ${${PROJECT_NAME}_SRCS})
+target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_17)
+# TODO(wjwwood): address all deprecation warnings and then remove this
+if(WIN32)
+  target_compile_definitions(${PROJECT_NAME} PUBLIC "_SILENCE_ALL_CXX17_DEPRECATION_WARNINGS")
+endif()
+target_include_directories(${PROJECT_NAME} PUBLIC
+  "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>"
+  "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>"
+  "$<INSTALL_INTERFACE:include/${PROJECT_NAME}>")
+target_link_libraries(${PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})
 # specific order: dependents before dependencies
 ament_target_dependencies(${PROJECT_NAME}
+  "ament_index_cpp"
   "libstatistics_collector"
   "rcl"
+  "rcl_interfaces"
   "rcl_yaml_param_parser"
   "rcpputils"
   "rcutils"
@@ -140,16 +212,21 @@ target_compile_definitions(${PROJECT_NAME}
   PRIVATE "RCLCPP_BUILDING_LIBRARY")
 
 install(
-  TARGETS ${PROJECT_NAME}
+  TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}
   ARCHIVE DESTINATION lib
   LIBRARY DESTINATION lib
   RUNTIME DESTINATION bin
 )
 
-# specific order: dependents before dependencies
-ament_export_include_directories(include)
+# Export old-style CMake variables
+ament_export_include_directories("include/${PROJECT_NAME}")
 ament_export_libraries(${PROJECT_NAME})
 
+# Export modern CMake targets
+ament_export_targets(${PROJECT_NAME})
+
+# specific order: dependents before dependencies
+ament_export_dependencies(ament_index_cpp)
 ament_export_dependencies(libstatistics_collector)
 ament_export_dependencies(rcl)
 ament_export_dependencies(rcpputils)
@@ -164,425 +241,22 @@ ament_export_dependencies(statistics_msgs)
 ament_export_dependencies(tracetools)
 
 if(BUILD_TESTING)
-  find_package(ament_cmake_gtest REQUIRED)
   find_package(ament_lint_auto REQUIRED)
   ament_lint_auto_find_test_dependencies()
 
-  find_package(rmw_implementation_cmake REQUIRED)
-
-  find_package(test_msgs REQUIRED)
-
-  include(cmake/rclcpp_add_build_failure_test.cmake)
-
-  add_definitions(-DTEST_RESOURCES_DIRECTORY="${CMAKE_CURRENT_BINARY_DIR}/test/resources")
-
-  ament_add_gtest(test_client test/test_client.cpp)
-  if(TARGET test_client)
-    ament_target_dependencies(test_client
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_client ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_create_timer test/test_create_timer.cpp)
-  if(TARGET test_create_timer)
-    ament_target_dependencies(test_create_timer
-      "rcl_interfaces"
-      "rmw"
-      "rcl"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_create_timer ${PROJECT_NAME})
-    target_include_directories(test_create_timer PRIVATE test/)
-  endif()
-  ament_add_gtest(test_expand_topic_or_service_name test/test_expand_topic_or_service_name.cpp)
-  if(TARGET test_expand_topic_or_service_name)
-    ament_target_dependencies(test_expand_topic_or_service_name
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_expand_topic_or_service_name ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_function_traits test/test_function_traits.cpp)
-  if(TARGET test_function_traits)
-    ament_target_dependencies(test_function_traits
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-  endif()
-  ament_add_gmock(test_intra_process_manager test/test_intra_process_manager.cpp)
-  if(TARGET test_intra_process_manager)
-    ament_target_dependencies(test_intra_process_manager
-      "rcl"
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_intra_process_manager ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_ring_buffer_implementation test/test_ring_buffer_implementation.cpp)
-  if(TARGET test_ring_buffer_implementation)
-    ament_target_dependencies(test_ring_buffer_implementation
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_ring_buffer_implementation ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_intra_process_buffer test/test_intra_process_buffer.cpp)
-  if(TARGET test_intra_process_buffer)
-    ament_target_dependencies(test_intra_process_buffer
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_intra_process_buffer ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_loaned_message test/test_loaned_message.cpp)
-  ament_target_dependencies(test_loaned_message
-    "test_msgs"
-  )
-  target_link_libraries(test_loaned_message ${PROJECT_NAME})
-
-  ament_add_gtest(test_node test/test_node.cpp TIMEOUT 240)
-  if(TARGET test_node)
-    ament_target_dependencies(test_node
-      "rcl_interfaces"
-      "rcpputils"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "test_msgs"
-    )
-    target_link_libraries(test_node ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_node_interfaces__get_node_interfaces
-    test/node_interfaces/test_get_node_interfaces.cpp)
-  if(TARGET test_node_interfaces__get_node_interfaces)
-    target_link_libraries(test_node_interfaces__get_node_interfaces ${PROJECT_NAME})
-  endif()
-
-  # TODO(wjwwood): reenable these build failure tests when I can get Jenkins to ignore their output
-  # rclcpp_add_build_failure_test(build_failure__get_node_topics_interface_const_ref_rclcpp_node
-  #   test/node_interfaces/test_does_not_compile/get_node_topics_interface_const_ref_rclcpp_node.cpp)
-  # target_link_libraries(build_failure__get_node_topics_interface_const_ref_rclcpp_node
-  #   ${PROJECT_NAME})
-
-  # rclcpp_add_build_failure_test(build_failure__get_node_topics_interface_const_ptr_rclcpp_node
-  #   test/node_interfaces/test_does_not_compile/get_node_topics_interface_const_ptr_rclcpp_node.cpp)
-  # target_link_libraries(build_failure__get_node_topics_interface_const_ptr_rclcpp_node
-  #   ${PROJECT_NAME})
-
-  # rclcpp_add_build_failure_test(build_failure__get_node_topics_interface_const_ref_wrapped_node
-  #   test/node_interfaces/test_does_not_compile/get_node_topics_interface_const_ref_wrapped_node.cpp)
-  # target_link_libraries(build_failure__get_node_topics_interface_const_ref_rclcpp_node
-  #   ${PROJECT_NAME})
-
-  # rclcpp_add_build_failure_test(build_failure__get_node_topics_interface_const_ptr_wrapped_node
-  #   test/node_interfaces/test_does_not_compile/get_node_topics_interface_const_ptr_wrapped_node.cpp)
-  # target_link_libraries(build_failure__get_node_topics_interface_const_ptr_rclcpp_node
-  #   ${PROJECT_NAME})
-
-  ament_add_gtest(test_node_global_args test/test_node_global_args.cpp)
-  if(TARGET test_node_global_args)
-    ament_target_dependencies(test_node_global_args
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_node_global_args ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_node_options test/test_node_options.cpp)
-  if(TARGET test_node_options)
-    ament_target_dependencies(test_node_options "rcl")
-    target_link_libraries(test_node_options ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_parameter_client test/test_parameter_client.cpp)
-  if(TARGET test_parameter_client)
-    ament_target_dependencies(test_parameter_client
-      "rcl_interfaces"
-    )
-    target_link_libraries(test_parameter_client ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_parameter_events_filter test/test_parameter_events_filter.cpp)
-  if(TARGET test_parameter_events_filter)
-    ament_target_dependencies(test_parameter_events_filter
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_parameter_events_filter ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_parameter test/test_parameter.cpp)
-  if(TARGET test_parameter)
-    ament_target_dependencies(test_parameter
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_parameter ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_parameter_map test/test_parameter_map.cpp)
-  if(TARGET test_parameter_map)
-    target_link_libraries(test_parameter_map ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_publisher test/test_publisher.cpp)
-  if(TARGET test_publisher)
-    ament_target_dependencies(test_publisher
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "test_msgs"
-    )
-    target_link_libraries(test_publisher ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_publisher_subscription_count_api test/test_publisher_subscription_count_api.cpp)
-  if(TARGET test_publisher_subscription_count_api)
-    ament_target_dependencies(test_publisher_subscription_count_api
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "test_msgs"
-    )
-    target_link_libraries(test_publisher_subscription_count_api ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_qos test/test_qos.cpp)
-  if(TARGET test_qos)
-    ament_target_dependencies(test_qos
-      "rmw"
-    )
-    target_link_libraries(test_qos
-      ${PROJECT_NAME}
-    )
-  endif()
-  ament_add_gtest(test_qos_event test/test_qos_event.cpp)
-  if(TARGET test_qos_event)
-    ament_target_dependencies(test_qos_event
-      "rmw"
-      "test_msgs"
-    )
-    target_link_libraries(test_qos_event
-      ${PROJECT_NAME}
-    )
-  endif()
-  ament_add_gtest(test_rate test/test_rate.cpp)
-  if(TARGET test_rate)
-    ament_target_dependencies(test_rate
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_rate
-      ${PROJECT_NAME}
-    )
-  endif()
-  ament_add_gtest(test_serialized_message_allocator test/test_serialized_message_allocator.cpp)
-  if(TARGET test_serialized_message_allocator)
-    ament_target_dependencies(test_serialized_message_allocator
-      test_msgs
-    )
-    target_link_libraries(test_serialized_message_allocator
-      ${PROJECT_NAME}
-    )
-  endif()
-  ament_add_gtest(test_serialized_message test/test_serialized_message.cpp)
-  if(TARGET test_serialized_message)
-    ament_target_dependencies(test_serialized_message
-      test_msgs
-    )
-    target_link_libraries(test_serialized_message
-      ${PROJECT_NAME}
-    )
-  endif()
-  ament_add_gtest(test_service test/test_service.cpp)
-  if(TARGET test_service)
-    ament_target_dependencies(test_service
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-    )
-    target_link_libraries(test_service ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_subscription test/test_subscription.cpp)
-  if(TARGET test_subscription)
-    ament_target_dependencies(test_subscription
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "test_msgs"
-    )
-    target_link_libraries(test_subscription ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_subscription_publisher_count_api test/test_subscription_publisher_count_api.cpp)
-  if(TARGET test_subscription_publisher_count_api)
-    ament_target_dependencies(test_subscription_publisher_count_api
-      "rcl_interfaces"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "test_msgs"
-    )
-    target_link_libraries(test_subscription_publisher_count_api ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_subscription_traits test/test_subscription_traits.cpp)
-  if(TARGET test_subscription_traits)
-    ament_target_dependencies(test_subscription_traits
-      "rcl"
-      "test_msgs"
-    )
-    target_link_libraries(test_subscription_traits ${PROJECT_NAME})
-  endif()
-  ament_add_gtest(test_find_weak_nodes test/test_find_weak_nodes.cpp)
-  if(TARGET test_find_weak_nodes)
-    ament_target_dependencies(test_find_weak_nodes
-      "rcl"
-    )
-    target_link_libraries(test_find_weak_nodes ${PROJECT_NAME})
-  endif()
-
-  set(append_library_dirs "${CMAKE_CURRENT_BINARY_DIR}")
-  if(WIN32)
-    set(append_library_dirs "${append_library_dirs}/$<CONFIG>")
-  endif()
-
-  ament_add_gtest(test_externally_defined_services test/test_externally_defined_services.cpp)
-  ament_target_dependencies(test_externally_defined_services
-    "rcl"
-    "test_msgs"
-  )
-  target_link_libraries(test_externally_defined_services ${PROJECT_NAME})
-
-  ament_add_gtest(test_duration test/test_duration.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_duration)
-    ament_target_dependencies(test_duration
-      "rcl")
-    target_link_libraries(test_duration ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_executor test/test_executor.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_executor)
-    ament_target_dependencies(test_executor
-      "rcl")
-    target_link_libraries(test_executor ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_logger test/test_logger.cpp)
-  target_link_libraries(test_logger ${PROJECT_NAME})
-
-  ament_add_gmock(test_logging test/test_logging.cpp)
-  target_link_libraries(test_logging ${PROJECT_NAME})
-
-  ament_add_gtest(test_time test/test_time.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_time)
-    ament_target_dependencies(test_time
-      "rcl")
-    target_link_libraries(test_time ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_timer test/test_timer.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_timer)
-    ament_target_dependencies(test_timer
-      "rcl")
-    target_link_libraries(test_timer ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_time_source test/test_time_source.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_time_source)
-    ament_target_dependencies(test_time_source
-      "rcl")
-    target_link_libraries(test_time_source ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_utilities test/test_utilities.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_utilities)
-    ament_target_dependencies(test_utilities
-      "rcl")
-    target_link_libraries(test_utilities ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_init test/test_init.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_init)
-    ament_target_dependencies(test_init
-      "rcl")
-    target_link_libraries(test_init ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_multi_threaded_executor test/executors/test_multi_threaded_executor.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_multi_threaded_executor)
-    ament_target_dependencies(test_multi_threaded_executor
-      "rcl")
-    target_link_libraries(test_multi_threaded_executor ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_guard_condition test/test_guard_condition.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_guard_condition)
-    target_link_libraries(test_guard_condition ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_wait_set test/test_wait_set.cpp
-    APPEND_LIBRARY_DIRS "${append_library_dirs}")
-  if(TARGET test_wait_set)
-    ament_target_dependencies(test_wait_set "test_msgs")
-    target_link_libraries(test_wait_set ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_subscription_topic_statistics test/topic_statistics/test_subscription_topic_statistics.cpp)
-  if(TARGET test_subscription_topic_statistics)
-    ament_target_dependencies(test_subscription_topic_statistics
-      "libstatistics_collector"
-      "rcl_interfaces"
-      "rcutils"
-      "rmw"
-      "rosidl_runtime_cpp"
-      "rosidl_typesupport_cpp"
-      "statistics_msgs"
-      "test_msgs")
-    target_link_libraries(test_subscription_topic_statistics ${PROJECT_NAME})
-  endif()
-
-  ament_add_gtest(test_subscription_options test/test_subscription_options.cpp)
-  if(TARGET test_subscription_options)
-    ament_target_dependencies(test_subscription_options "rcl")
-    target_link_libraries(test_subscription_options ${PROJECT_NAME})
-  endif()
-
-  # Install test resources
-  install(
-    DIRECTORY test/resources
-    DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/test)
+  add_subdirectory(test)
 endif()
 
 ament_package()
 
 install(
   DIRECTORY include/ ${CMAKE_CURRENT_BINARY_DIR}/include/
-  DESTINATION include
+  DESTINATION include/${PROJECT_NAME}
 )
+
+if(TEST cppcheck)
+  # must set the property after ament_package()
+  set_tests_properties(cppcheck PROPERTIES TIMEOUT 500)
+endif()
+
+ament_generate_version_header(${PROJECT_NAME})

rclcpp/Doxyfile

@@ -21,13 +21,22 @@ GENERATE_LATEX         = NO
 ENABLE_PREPROCESSING   = YES
 MACRO_EXPANSION        = YES
 EXPAND_ONLY_PREDEF     = YES
-PREDEFINED             = RCLCPP_PUBLIC=
+PREDEFINED             += DOXYGEN_ONLY
+PREDEFINED             += RCLCPP_LOCAL=
+PREDEFINED             += RCLCPP_PUBLIC=
+PREDEFINED             += RCLCPP_PUBLIC_TYPE=
+PREDEFINED             += RCUTILS_WARN_UNUSED=
+PREDEFINED             += RCPPUTILS_TSA_GUARDED_BY(x)=
+PREDEFINED             += RCPPUTILS_TSA_PT_GUARDED_BY(x)=
+PREDEFINED             += RCPPUTILS_TSA_REQUIRES(x)=
+
+DOT_GRAPH_MAX_NODES    = 101
 
 # Tag files that do not exist will produce a warning and cross-project linking will not work.
-TAGFILES += "../../../../doxygen_tag_files/cppreference-doxygen-web.tag.xml=http://en.cppreference.com/w/"
+#TAGFILES += "../../../../doxygen_tag_files/cppreference-doxygen-web.tag.xml=http://en.cppreference.com/w/"
 # Consider changing "latest" to the version you want to reference (e.g. beta1 or 1.0.0)
-TAGFILES += "../../../../doxygen_tag_files/rcl.tag=http://docs.ros2.org/latest/api/rcl/"
-TAGFILES += "../../../../doxygen_tag_files/rmw.tag=http://docs.ros2.org/latest/api/rmw/"
-TAGFILES += "../../../../doxygen_tag_files/rcutils.tag=http://docs.ros2.org/latest/api/rcutils/"
+#TAGFILES += "../../../../doxygen_tag_files/rcl.tag=http://docs.ros2.org/latest/api/rcl/"
+#TAGFILES += "../../../../doxygen_tag_files/rmw.tag=http://docs.ros2.org/latest/api/rmw/"
+#TAGFILES += "../../../../doxygen_tag_files/rcutils.tag=http://docs.ros2.org/latest/api/rcutils/"
 # Uncomment to generate tag files for cross-project linking.
 #GENERATE_TAGFILE = "../../../../doxygen_tag_files/rclcpp.tag"

rclcpp/QUALITY_DECLARATION.md

@@ -0,0 +1,228 @@
+This document is a declaration of software quality for the `rclcpp` package, based on the guidelines in [REP-2004](https://www.ros.org/reps/rep-2004.html).
+
+# rclcpp Quality Declaration
+
+The package `rclcpp` claims to be in the **Quality Level 1** category when it is used with a **Quality Level 1** middleware.
+
+Below are the rationales, notes, and caveats for this claim, organized by each requirement listed in the [Package Quality Categories in REP-2004](https://www.ros.org/reps/rep-2004.html) of the ROS2 developer guide.
+
+## Version Policy [1]
+
+### Version Scheme [1.i]
+
+`rclcpp` uses `semver` according to the recommendation for ROS Core packages in the [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#versioning).
+
+### Version Stability [1.ii]
+
+`rclcpp` is at a stable version, i.e. `>= 1.0.0`.
+The current version can be found in its [package.xml](package.xml), and its change history can be found in its [CHANGELOG](CHANGELOG.rst).
+
+### Public API Declaration [1.iii]
+
+All symbols in the installed headers are considered part of the public API.
+
+Except for the exclusions listed below, all installed headers are in the `include` directory of the package, headers in any other folders are not installed and considered private.
+Headers under the folder `experimental` are not considered part of the public API as they have not yet been stabilized. These symbols are namespaced `rclcpp::experimental`.
+Headers under the folder `detail` are not considered part of the public API and are subject to change without notice. These symbols are namespaced `rclcpp::detail`.
+
+### API Stability Policy [1.iv]
+
+`rclcpp` will not break public API within a released ROS distribution, i.e. no major releases once the ROS distribution is released.
+
+### ABI Stability Policy [1.v]
+
+`rclcpp` contains C++ code and therefore must be concerned with ABI stability, and will maintain ABI stability within a ROS distribution.
+
+### ABI and ABI Stability Within a Released ROS Distribution [1.vi]
+
+`rclcpp` will not break API nor ABI within a released ROS distribution, i.e. no major releases once the ROS distribution is released.
+
+## Change Control Process [2]
+
+`rclcpp` follows the recommended guidelines for ROS Core packages in the [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#change-control-process).
+
+### Change Requests [2.i]
+
+All changes will occur through a pull request, check [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#change-control-process) for additional information.
+
+### Contributor Origin [2.ii]
+
+This package uses DCO as its confirmation of contributor origin policy. More information can be found in [CONTRIBUTING](../CONTRIBUTING.md).
+
+### Peer Review Policy [2.iii]
+
+All pull requests will be peer-reviewed, check [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#change-control-process) for additional information.
+
+### Continuous Integration [2.iv]
+
+All pull requests must pass CI on all [tier 1 platforms](https://www.ros.org/reps/rep-2000.html#support-tiers)
+
+Currently nightly results can be seen here:
+
+* [linux-aarch64_release](https://ci.ros2.org/view/nightly/job/nightly_linux-aarch64_release/lastBuild/testReport/rclcpp/)
+* [linux_release](https://ci.ros2.org/view/nightly/job/nightly_linux_release/lastBuild/testReport/rclcpp/)
+* [mac_osx_release](https://ci.ros2.org/view/nightly/job/nightly_osx_release/lastBuild/testReport/rclcpp/)
+* [windows_release](https://ci.ros2.org/view/nightly/job/nightly_win_rel/lastBuild/testReport/rclcpp/)
+
+###  Documentation Policy [2.v]
+
+All pull requests must resolve related documentation changes before merging.
+
+## Documentation [3]
+
+### Feature Documentation [3.i]
+
+`rclcpp` has a [feature list](http://docs.ros2.org/latest/api/rclcpp/) and each item in the list links to the corresponding feature documentation. There is documentation for all of the features, and new features require documentation before being added.
+
+### Public API Documentation [3.ii]
+
+The API is publicly available in its [ROS 2 API documentation](http://docs.ros2.org/latest/api/rclcpp/).
+
+### License [3.iii]
+
+The license for `rclcpp` is Apache 2.0, and a summary is in each source file, the type is declared in the [`package.xml`](./package.xml) manifest file, and a full copy of the license is in the [`LICENSE`](../LICENSE) file.
+
+There is an automated test which runs a linter that ensures each file has a license statement. [Here](http://build.ros2.org/view/Rpr/job/Rpr__rclcpp__ubuntu_focal_amd64/lastCompletedBuild/testReport/rclcpp/) can be found a list with the latest results of the various linters being run on the package.
+
+### Copyright Statements [3.iv]
+
+The copyright holders each provide a statement of copyright in each source code file in `rclcpp`.
+
+There is an automated test which runs a linter that ensures each file has at least one copyright statement. Latest linter result report can be seen [here](http://build.ros2.org/view/Rpr/job/Rpr__rclcpp__ubuntu_focal_amd64/lastCompletedBuild/testReport/rclcpp/copyright/).
+
+## Testing [4]
+
+### Feature Testing [4.i]
+
+Each feature in `rclcpp` has corresponding tests which simulate typical usage, and they are located in the [`test`](https://github.com/ros2/rclcpp/tree/master/test) directory.
+New features are required to have tests before being added.
+
+Currently nightly test results can be seen here:
+
+* [linux-aarch64_release](https://ci.ros2.org/view/nightly/job/nightly_linux-aarch64_release/lastBuild/testReport/rclcpp/)
+* [linux_release](https://ci.ros2.org/view/nightly/job/nightly_linux_release/lastBuild/testReport/rclcpp/)
+* [mac_osx_release](https://ci.ros2.org/view/nightly/job/nightly_osx_release/lastBuild/testReport/rclcpp/)
+* [windows_release](https://ci.ros2.org/view/nightly/job/nightly_win_rel/lastBuild/testReport/rclcpp/)
+
+### Public API Testing [4.ii]
+
+Each part of the public API has tests, and new additions or changes to the public API require tests before being added.
+The tests aim to cover both typical usage and corner cases, but are quantified by contributing to code coverage.
+
+### Coverage [4.iii]
+
+`rclcpp` follows the recommendations for ROS Core packages in the [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#code-coverage), and opts to use line coverage instead of branch coverage.
+
+This includes:
+
+- tracking and reporting line coverage statistics
+- achieving and maintaining a reasonable branch line coverage (90-100%)
+- no lines are manually skipped in coverage calculations
+
+Changes are required to make a best effort to keep or increase coverage before being accepted, but decreases are allowed if properly justified and accepted by reviewers.
+
+Current coverage statistics can be viewed [here](https://ci.ros2.org/job/nightly_linux_coverage/lastCompletedBuild/cobertura/src_ros2_rclcpp_rclcpp_src_rclcpp/). A description of how coverage statistics are calculated is summarized in this page ["ROS 2 Onboarding Guide"](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#note-on-coverage-runs).
+
+`rclcpp` has a line coverage `>= 95%`, which is calculated over all directories within `rclcpp` with the exception of the `experimental` directory.
+
+### Performance [4.iv]
+
+`rclcpp` follows the recommendations for performance testing of C/C++ code in the [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#performance), and opts to do performance analysis on each release rather than each change.
+
+The performance tests of `rclcpp` are located in the [test/benchmark directory](https://github.com/ros2/rclcpp/tree/master/rclcpp/test/benchmark).
+
+System level performance benchmarks that cover features of `rclcpp` can be found at:
+* [Benchmarks](http://build.ros2.org/view/Rci/job/Rci__benchmark_ubuntu_focal_amd64/BenchmarkTable/)
+* [Performance](http://build.ros2.org/view/Rci/job/Rci__nightly-performance_ubuntu_focal_amd64/lastCompletedBuild/)
+
+Changes that introduce regressions in performance must be adequately justified in order to be accepted and merged.
+
+### Linters and Static Analysis [4.v]
+
+`rclcpp` uses and passes all the ROS2 standard linters and static analysis tools for a C++ package as described in the [ROS 2 Developer Guide](https://docs.ros.org/en/rolling/Contributing/Developer-Guide.html#linters-and-static-analysis). Passing implies there are no linter/static errors when testing against CI of supported platforms.
+
+Currently nightly test results can be seen here:
+* [linux-aarch64_release](https://ci.ros2.org/view/nightly/job/nightly_linux-aarch64_release/lastBuild/testReport/rclcpp/)
+* [linux_release](https://ci.ros2.org/view/nightly/job/nightly_linux_release/lastBuild/testReport/rclcpp/)
+* [mac_osx_release](https://ci.ros2.org/view/nightly/job/nightly_osx_release/lastBuild/testReport/rclcpp/)
+* [windows_release](https://ci.ros2.org/view/nightly/job/nightly_win_rel/lastBuild/testReport/rclcpp/)
+
+## Dependencies [5]
+
+Below are evaluations of each of `rclcpp`'s run-time and build-time dependencies that have been determined to influence the quality.
+
+It has several "buildtool" dependencies, which do not affect the resulting quality of the package, because they do not contribute to the public library API.
+
+It also has several test dependencies, which do not affect the resulting quality of the package, because they are only used to build and run the test code.
+
+### Direct and Optional Runtime ROS Dependencies [5.i]/[5.ii]
+
+`rclcpp` has the following runtime ROS dependencies:
+
+#### `libstatistics_collector`
+
+The `libstatistics_collector` package provides lightweight aggregation utilities to collect statistics and measure message metrics.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros-tooling/libstatistics_collector/tree/master/QUALITY_DECLARATION.md).
+
+#### `rcl`
+
+`rcl` a library to support implementation of language specific ROS 2 Client Libraries.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rcl/blob/master/rcl/QUALITY_DECLARATION.md).
+
+#### `rcl_yaml_param_parser`
+
+The `rcl_yaml_param_parser` package provides an API that is used to parse YAML configuration files which may be used to configure ROS and specific nodes.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rcl/tree/master/rcl_yaml_param_parser/QUALITY_DECLARATION.md).
+
+#### `rcpputils`
+
+The `rcpputils` package provides an API which contains common utilities and data structures useful when programming in C++.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rcpputils/blob/master/QUALITY_DECLARATION.md).
+
+#### `rcutils`
+
+The `rcutils` package provides an API which contains common utilities and data structures useful when programming in C.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rcutils/blob/master/QUALITY_DECLARATION.md).
+
+#### `rmw`
+
+`rmw` is the ROS 2 middleware library.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rmw/blob/master/rmw/QUALITY_DECLARATION.md).
+
+#### `statistics_msgs`
+
+The `statistics_msgs` package contains ROS 2 message definitions for reporting statistics for topics and system resources.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://github.com/ros2/rcl_interfaces/blob/master/statistics_msgs/QUALITY_DECLARATION.md).
+
+#### `tracetools`
+
+The `tracetools` package provides utilities for instrumenting the code in `rclcpp` so that it may be traced for debugging and performance analysis.
+
+It is **Quality Level 1**, see its [Quality Declaration document](https://gitlab.com/ros-tracing/ros2_tracing/-/blob/master/tracetools/QUALITY_DECLARATION.md).
+
+### Direct Runtime non-ROS Dependency [5.iii]
+
+`rclcpp` has no run-time or build-time dependencies that need to be considered for this declaration.
+
+## Platform Support [6]
+
+`rclcpp` supports all of the tier 1 platforms as described in [REP-2000](https://www.ros.org/reps/rep-2000.html#support-tiers), and tests each change against all of them.
+
+Currently nightly build status can be seen here:
+* [linux-aarch64_release](https://ci.ros2.org/view/nightly/job/nightly_linux-aarch64_release/lastBuild/rclcpp/)
+* [linux_release](https://ci.ros2.org/view/nightly/job/nightly_linux_release/lastBuild/rclcpp/)
+* [mac_osx_release](https://ci.ros2.org/view/nightly/job/nightly_osx_release/lastBuild/rclcpp/)
+* [windows_release](https://ci.ros2.org/view/nightly/job/nightly_win_rel/lastBuild/rclcpp/)
+
+## Security
+
+### Vulnerability Disclosure Policy [7.i]
+
+This package conforms to the Vulnerability Disclosure Policy in [REP-2006](https://www.ros.org/reps/rep-2006.html).

rclcpp/README.md

@@ -0,0 +1,9 @@
+# `rclcpp`
+
+The ROS client library in C++.
+
+Visit the [rclcpp API documentation](http://docs.ros2.org/latest/api/rclcpp/) for a complete list of its main components and features.
+
+## Quality Declaration
+
+This package claims to be in the **Quality Level 1** category, see the [Quality Declaration](QUALITY_DECLARATION.md) for more details.

rclcpp/doc/api_review_march_2020.md

@@ -0,0 +1,437 @@
+# API Review for `rclcpp` from March 2020
+
+## Notes
+
+### Off-Topic Questions
+
+> [rclcpp_action] There exists a thread-safe and non-thread-safe way to get the goal result from an action client. We probably want to remove the public interface to the non-thread safe call (or consolidate somehow): https://github.com/ros2/rclcpp/issues/955
+
+`rclcpp_action` is out of scope atm.
+
+**Notes from 2020-03-19**: To be handled in separate API review.
+
+## Architecture
+
+### Calling Syntax and Keeping Node-like Class APIs in Sync
+
+> Currently, much of the API is exposed via the `rclcpp::Node` class, and due to the nature of the current architecture there is a lot of repeated code to expose these methods and then call the implementations which are in other classes like `rclcpp::node_interfaces::NodeTopics`, for example.
+>
+> Also, we have other versions of the class `rclcpp::Node` with different semantics and interfaces, like `rclcpp_lifecycle::LifecycleNode`, and we have been having trouble keeping the interface provided there up to date with how things are done in `rclcpp::Node`. Since `LifecycleNode` has a different API from `Node` in some important cases, it does not just inherit from `Node`.
+>
+> There are two main proposals (as I see it) to try and address this issue, either (a) break up the functionality in `Node` so that it is in separate classes and make `Node` multiple inherit from those classes, and then `LifecycleNode` could selectively inherit from those as well, or (b) change our calling convention from `node->do_thing(...)` to be `do_thing(node, ...)`.
+>
+> For (a) which commonly referred to as the [Policy Based Design Pattern](https://en.wikipedia.org/wiki/Modern_C%2B%2B_Design#Policy-based_design), we'd be reversing previous design decisions which we discussed at length where we decided to use composition over inheritance for various reasons.
+> One of the reasons was testing, with the theory that having simpler separate interfaces we could more easily mock them as needed for testing.
+> The testing goal would still be met, either by keeping the "node_interface" classes as-is or by mocking the classes that node would multiple inherit from, however it's harder to indicate that a function needs a class that multiple inherits from several classes but not others.
+> Also having interdependency between the classes which are inherited from is a bit complicated in this design pattern.
+>
+> For (b), we would be changing how we recommend all code be written (not a trivial thing to do at all), because example code like `auto pub = node->create_publsiher(...);` would be come `auto pub = create_publisher(node, ...);`.
+> This has some distinct advantages, however, in that it allows us to write these functions, like `create_publisher(node, ...)`, so that the node argument can be any class that meets the criteria of the function.
+> That not only means that when we add a feature it automatically works with `Node` and `LifecycleNode` without adding anything to them, it also means that user defined `Node`-like classes will also work, even if they do not inherit from or provide the complete interface for `rclcpp::Node`.
+> Another major downside of this approach is discoverability of the API when using auto-completion in text editors, as `node-><tab>` will often give you a list of methods to explore, but with the new calling convention, there's not way to get an auto complete for code who's first argument is a `Node`-like class.
+>
+> Both of the above approaches address some of the main concerns, which are: keeping `Node` and `LifecycleNode` in sync, reducing the size of the `Node` class so it is more easily maintained, documented, and so that related functions are grouped more clearly.
+
+- https://github.com/ros2/rclcpp/issues/898
+- https://github.com/ros2/rclcpp/issues/509
+- https://github.com/ros2/rclcpp/issues/855
+- https://github.com/ros2/rclcpp/issues/985
+  - subnode feature is in rclcpp::Node only, complicating "node using" API designs
+- http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4174.pdf
+- https://en.wikipedia.org/wiki/Uniform_Function_Call_Syntax#C++_proposal
+  - "Many programmers are tempted to write member functions to get the benefits of the member function syntax (e.g. "dot-autocomplete" to list member functions);[6] however, this leads to excessive coupling between classes.[7]"
+
+**Suggested Action**: Document the discussion and defer until Foxy.
+
+**Notes from 2020-03-19**:
+
+- Another version of (b) could be to have classes that are constructed with node, e.g. `Publisher(node, ...)` rather than `node->create_publisher(...)`
+- (tfoote) interface class? `NodeInterface<NodeLike>::something(node_like)`
+  - DRY?
+  - `NodeInterface<LifecycleNode>::<tab>` -> only life cycle node methods
+- (karsten) use interface classes directly, e.g. node->get_X_interface()->do_thing()
+- (dirk) use macros to add methods to class
+  - Question: Do we want tab-completable API (specifically list of member functions)?
+- Question: Is consistency in calling between core and non-core features more important than tab-completion?
+- Add better example of adding new feature and not needing to touch `rclcpp::Node`.
+- (dirk) methods and free functions not mutually exclusive.
+
+### Scoped Versus Non-Scoped Entities (e.g. Publishers/Subscriptions)
+
+> Currently, Publisher and Subscription (and similar entities) are scoped, meaning that when they are created they are added to the ROS graph as a side effect, and when they are let out of scope they remove themselves from the graph too.
+> Additionally, they necessarily have shared state with the system, for instance when you are spinning on a node, the executor shares ownership of the Subscriptions with the user.
+> Therefore, the Subscription only gets removed when both the user and executor are done with it.
+>
+> This shared ownership is accomplished with the use of shared pointers and weak pointers.
+>
+> There are a few concerns here, (a) use of shared pointers confuses users, (b) overhead of shared pointers and lack of an ability to use these classes on the stack rather than the heap, and (c) complexity of shutdown of an entity from the users perspective.
+>
+> For (a), some users are overwhelmed by the need to use a shared pointer.
+> In ROS 1 this was avoided by having a class which itself just thinly wraps a shared pointer (see: https://github.com/ros/ros_comm/blob/ac9f88c59a676ca6895e13445fc7d71f398ebe1f/clients/roscpp/include/ros/subscriber.h#L108-L111).
+> This could be achieved in ROS 2 either by doing the same with a wrapper class (at the expense of lots of repeated code), or by eliminating the need for using shared ownership.
+>
+> For (b), for some use cases, especially resource constrained / real-time / safety-critical environments, requiring these classes to be on the heap rather than the stack is at least inconvenient.
+> Additionally, there is a cost associated with using shared pointers, in the storage of shared state and in some implementation the use of locks or at least atomics for thread-safety.
+>
+> For (c), this is the most concerning drawback, because right now when a user lets their shared pointer to a, for example, Subscription go out of scope, a post condition is not that the Subscription is destroyed, nor that it has been removed from the graph.
+> In stead, the behavior is more like "at some point in the future the Subscription will be destroyed and removed from the graph, when the system is done with it".
+> This isn't a very satisfactory contract, as some users may wish to know when the Subscription has been deleted, but cannot easily know that.
+>
+> The benefit to the shared state is a safety net for users.
+> The alternative would be to document that a Subscription, again for example, cannot be deleted until the system is done with it.
+> We'd basically be pushing the responsibility onto the user to ensure the shared ownership is handled properly by the execution of their application, i.e. they create the Subscription, share a reference with the system (adding it by reference to an executor, for example), and they have to make sure the system is done with it before deleting the Subscription.
+>
+>Separately, from the above points, there is the related concern of forcing the user to keep a copy of their entities in scope, whether it be with a shared pointer or a class wrapping one.
+> There is the desire to create it and forget it in some cases.
+> The downside to this is that if/when the user wants to destroy the entity, they have no way of doing that as they have no handle or unique way to address the entity.
+>
+> One proposed solution would be to have a set of "named X" APIs, e.g. `create_named_subscription` rather than just `create_subscription`.
+> This would allow the user to address the Subscription in the future in order to obtain a new reference to it or delete it.
+
+- https://github.com/ros2/rclcpp/issues/506
+- https://github.com/ros2/rclcpp/issues/726
+
+**Suggested Action**: Consolidate to a single issue, and defer.
+
+**Notes from 2020-03-23**:
+
+- (chris) Putting ownership mechanics on user is hard.
+- (dirk) add documentation clearly outlining ownership
+- (shane) warn on unused to catch issues with immediately deleted items
+- (tfoote) debugging output for destruction so it easy to see when reviewing logs
+- (chris) possible to create API that checks for destruction
+  - (william) might lead to complex synchronization issues
+- (tfoote) could add helper classes to make scoped things non-scoped
+  - (shane) concerned that there is no longer "one good way" to do it
+
+### Allow QoS to be configured externally, like we allow remapping of topic names
+
+> Suggestion from @stonier: allow the qos setting on a topic to be changed externally at startup, similar to how we do topic remapping (e.g., do it on the command-line using appropriate syntax).
+>
+> To keep the syntax manageable, we might just allow profiles to be picked.
+
+- https://github.com/ros2/rclcpp/issues/239
+
+**Suggested Action**: Update issue, defer for now.
+
+**Notes from 2020-03-19**:
+
+- (wjwwood) it depends on the QoS setting, but many don't make sense, mostly because they can change some of the behaviors of underlying API
+- (dirk) Should developers expose a parameter instead?
+- (multiple) should be a feature that makes configuring them (after opt-in) consistent
+- (jacob) customers feedback was that this was expected, surprised it was not allowed
+- (karsten) could limit to profiles
+
+## Init/shutdown and Context
+
+### Consider renaming `rclcpp::ok()`
+
+> Old discussion to rename `rclcpp::ok()` to something more specific, like `rclcpp::is_not_shutdown()` or the corollary `rclcpp::is_shutdown()`.
+
+- https://github.com/ros2/rclcpp/issues/3
+
+**Suggested Action**: Defer.
+
+**Notes from 2020-03-19**:
+
+- (shane) preference to not have a negative in the function name
+
+## Executor
+
+### Exposing Scheduling of Tasks in Executor and a Better Default
+
+> Currently there is a hard coded procedure for handling ready tasks in the executor, first timers, then subscriptions, and so on.
+> This scheduling is not fair and results in non-deterministic behavior and starvation issues.
+>
+> We should provide a better default scheduling which is fairer and ideally deterministic, something like round-robin or FIFO.
+>
+> Additionally, we should make it easier to let the user override the scheduling logic in the executor.
+
+- https://github.com/ros2/rclcpp/pull/614
+- https://github.com/ros2/rclcpp/issues/633
+- https://github.com/ros2/rclcpp/issues/392
+
+**Suggested Action**: Follow up on proposals to implement FIFO scheduling and refactor the Executor design to more easily expose the scheduling logic.
+
+**Notes from 2020-03-19**:
+
+- No comments.
+
+### Make it possible to wait on entities (e.g. Subscriptions) without an Executor
+
+> Currently, it is only possible to use things like Timers and Subscriptions and Services with an executor.
+> It should be possible, however, to either poll these entities or wait on them and then decide which to process as a user.
+>
+> This is most easily accomplished with a WaitSet-like class.
+
+- https://github.com/ros2/rclcpp/issues/520
+
+**Suggested Action**: implement WaitSet class in rclcpp so that this is possible, and make "waitable" entities such that they can be polled, e.g. `Subscription`s should have a user facing `take()` method, which can fail if no data is available.
+
+**Notes from 2020-03-19**:
+
+- No comments.
+
+### Make it possible to use multiple executors per node
+
+> Currently, you cannot use more than one executor per node, this limits your options when it comes to distributing work within a node across threads.
+> You can use a multi-threaded executor, or make your own executor which does this, but it is often convenient to be able to spin part of the node separately from the the rest of the node.
+
+- https://github.com/ros2/rclcpp/issues/519
+
+**Suggested Action**: Make this possible, moving the exclusivity to be between an executor and callback groups rather than nodes.
+
+**Notes from 2020-03-19**:
+
+- No comments.
+
+### Implement a Lock-free Executor
+
+> This would presumably be useful for real-time and safety critical systems where locks and any kind of blocking code is considered undesirable.
+
+- https://github.com/ros2/rclcpp/issues/77
+
+**Suggested Action**: Keep in backlog until someone needs it specifically.
+
+**Notes from 2020-03-19**:
+
+- No comments.
+
+### Add implementation of `spin_some()` to the `MultiThreadedExecutor`
+
+> Currently `spin_some()` is only available in the `SingleThreadedExecutor`.
+
+- https://github.com/ros2/rclcpp/issues/85
+
+**Suggested Action**: Defer.
+
+**Notes from 2020-03-19**:
+
+- No comments.
+
+## Node
+
+### Do argument parsing outside of node constructor
+
+> Things that come from command line arguments should be separately passed into the node's constructor rather than passing in arguments and asking the node to do the parsing.
+
+- https://github.com/ros2/rclcpp/issues/492
+
+**Suggested Action**: Defer until after foxy.
+
+**Notes from 2020-03-23**:
+
+- (dirk) may be related to ROS 1 heritage of argc/argv being passed to node directly
+- (shane) impacts rcl API as well, two parts "global options" as well node specific options
+- (dirk) what is the recommendation to users that want to add arguments programmatically
+  - user should be able to get non-ros argc/argv somehow (seems like you can now)
+- (jacob) the argument in NodeOptions are used for application specific argument via component loading as well
+
+## Timer
+
+### Timer based on ROS Time
+
+> `node->create_wall_timer` does exactly what it says; creates a timer that will call the callback when the wall time expires.  But this is almost never what the user wants, since this won’t work properly in simulation.  Suggestion: deprecate `create_wall_timer`, add a new method called `create_timer` that takes the timer to use as one of the arguments, which defaults to ROS_TIME.
+
+- https://github.com/ros2/rclcpp/blob/96ebf59a6045a535730d98fff25e522807c7aa75/rclcpp/include/rclcpp/node.hpp#L219-L230
+- https://github.com/ros2/rclcpp/issues/465
+
+**Suggested Action**: Promote `rclcpp::create_timer()` which is templated on a clock type, as suggested, but leave `create_wall_timer` as a convenience.
+
+**Notes from 2020-03-19**:
+
+- (shane) may be a `rclcpp::create_timer()` that can be used to create a non-wall timer already
+
+## Publisher
+
+## Subscription
+
+### Callback Signature
+
+> Is there a reason the subscription callback must have a smart pointer argument instead of accepting a const-reference argument?
+
+- https://github.com/ros2/rclcpp/blob/96ebf59a6045a535730d98fff25e522807c7aa75/rclcpp/include/rclcpp/any_subscription_callback.hpp#L44-L52
+- https://github.com/ros2/rclcpp/issues/281
+
+**Suggested Action**: Provide const reference as an option, add documentation as to the implications of one callback signature versus others.
+
+**Notes from 2020-03-19**:
+
+- (dirk) have const reference and document it
+
+## Service Server
+
+### Allow for asynchronous Service Server callbacks
+
+> Currently, the only callback signature for Service Servers takes a request and must return a response.
+> This means that all of the activity of the service server has to happen within that function.
+> This can cause issues, specifically if you want to call another service within the current service server's callback, as it causes deadlock issues trying to synchronously call the second service within a spin callback.
+> More generally, it seems likely that long running service server callbacks may be necessary in the future and requiring them to be synchronous would tie up at least on thread in the spinning executor unnecessarily.
+
+- https://github.com/ros2/rclcpp/issues/491
+
+**Suggested Action**: Defer.
+
+**Notes from 2020-03-23**:
+
+- (dirk) likely new API, so possible to backport
+
+## Service Client
+
+### Callback has SharedFuture rather than const reference to response
+
+> Why does the Client::send_async_request take in a callback that has a SharedFuture argument instead of an argument that is simply a const-reference (or smart pointer) to the service response type? The current API seems to imply that the callback ought to check whether the promise is broken or fulfilled before trying to access it. Is that the case? If so, it should be documented in the header.
+
+- https://github.com/ros2/rclcpp/blob/7c1721a0b390be8242a6b824489d0bc861f6a0ad/rclcpp/include/rclcpp/client.hpp#L134
+
+**Suggested Action**: Update ticket and defer.
+
+**Notes from 2020-03-19**:
+
+- (wjwwood) we wanted the user to handle error cases with the future?
+- (dirk) future allows for single callback (rather than one for response and one for error)
+- (jacob) actions uses a "wrapped result" object
+
+### rclcpp missing synchronous `send_request` and issues with deadlocks
+
+> This has been reported by several users, but there is only an `async_send_request` currently. `rclpy` has a synchronous `send_request` but  it has issues with deadlock, specifically if you call it without spinning in another thread then it will deadlock. Or if you call it from within a spin callback when using a single threaded executor, it will deadlock.
+
+- https://discourse.ros.org/t/synchronous-request-to-service-in-callback-results-in-deadlock/12767
+- https://github.com/ros2/rclcpp/issues/975
+- https://github.com/ros2/demos/blob/948b4f4869298f39cfe99d3ae517ad60a72a8909/demo_nodes_cpp/src/services/add_two_ints_client.cpp#L24-L39
+
+**Suggested Action**: Update issue and defer. Also defer decision on reconciling rclpy's send_request.
+
+**Notes from 2020-03-23**:
+
+- (karsten/shane) async spinner helps in rclpy version, rclcpp could emulate
+- (chris) sees three options:
+  - only async (current case in rclcpp)
+  - have sync version, add lots of docs that spinning needs to happen elsewhere (current case for rclpy)
+  - reentrant spinning
+- (william) you either need async/await from language or ".then" syntax (we have this in async_send_request())
+- (chris) more error checking for recursive spinning
+- (chris) weird that rclcpp and rclpy have different API
+- (shane) thinks it is ok to have different API, but rclpy is not ideal
+
+## Parameters
+
+### Expected vs Unexpected parameters
+
+> Allow node author to define expected parameters and what happens when an unexpected parameter is set.
+
+- https://github.com/ros2/rclcpp/issues/475
+- https://github.com/ros2/rclcpp/tree/check_parameters
+
+**Suggested Action**: Defer as nice to have.
+
+**Notes from 2020-03-23**:
+
+- None.
+
+### Implicitly cast integer values for double parameters
+
+> If we try to pass an integer value to a double parameter from the command line or from a parameters YAML file we get a `rclcpp::ParameterTypeException`.
+> For example, passing a parameter from the command line:
+>
+>     ros2 run foo_package foo_node --ros-args -p foo_arg:=1
+>
+> results in the following error:
+>
+>     terminate called after throwing an instance of 'rclcpp::ParameterTypeException'
+>       what():  expected [double] got [integer]
+>
+> and we can fix it by explicitly making our value a floating point number:
+>
+>     ros2 run foo_package foo_node --ros-args -p foo_arg:=1.0
+>
+> But, it seems reasonable to me that if a user forgets to explicitly provide a floating point value that we should implicitly cast an integer to a float (as is done in many programming languages).
+
+- https://github.com/ros2/rclcpp/issues/979
+
+**Suggested Action**: Continue with issue.
+
+**Notes from 2020-03-23**:
+
+- (shane) says "yes please" :)
+
+### Use `std::variant` instead of custom `ParameterValue` class
+
+> This is only possible if C++17 is available, but it would simplify our code, make our interface more standard, and allow us to use constexpr-if to simply our templated code.
+
+**Suggested Action**: Create an issue for future work.
+
+**Notes from 2020-03-23**:
+
+- (chris) not sure churn is worth
+- (ivan) other places for std::variant, like AnySubscriptionCallback
+
+### Cannot set name or value on `Parameter`/`ParameterValue`
+
+> Both `Parameter` and `ParameterValue` are read-only after construction.
+
+- https://github.com/ros2/rclcpp/issues/238
+
+**Suggested Action**: Update issue, possibly close.
+
+**Notes from 2020-03-23**:
+
+- (chris/william) setting values on temporary (local) objects is not reflected in the node, so misleading
+
+## Parameter Clients
+
+### No timeout option with synchronous parameter client calls
+
+> As an example, SyncParametersClient::set_parameters doesn't take a timeout option. So, if anything goes wrong in the service call (e.g. the server goes down), we will get stuck waiting indefinitely.
+
+- https://github.com/ros2/rclcpp/issues/360
+- https://github.com/ros2/rclcpp/blob/96ebf59a6045a535730d98fff25e522807c7aa75/rclcpp/src/rclcpp/parameter_client.cpp#L453-L468
+
+**Suggested Action**: Update issue, decide if it can be taken for Foxy or not.
+
+**Notes from 2020-03-23**:
+
+- (tfoote) Seems like adding a timeout is a good idea.
+
+### Name of AsyncParametersClient inconsistent
+
+> AsyncParameter**s**Client uses plural, when filename is singular (and ParameterService is singular):
+
+- https://github.com/ros2/rclcpp/blob/7c1721a0b390be8242a6b824489d0bc861f6a0ad/rclcpp/include/rclcpp/parameter_client.hpp#L44
+
+**Suggested Action**: Reconcile class and file name, switch to singular name?
+
+**Notes from on-line, post 2020-03-23 meeting**:
+
+- (tfoote) +1 for homogenizing to singular
+
+### `SyncParametersClient::get_parameters` doesn't allow you to detect error cases
+
+> E.g. https://github.com/ros2/rclcpp/blob/249b7d80d8f677edcda05052f598de84f4c2181c/rclcpp/src/rclcpp/parameter_client.cpp#L246-L257 returns an empty vector if something goes wrong which is also a valid response.
+
+- https://github.com/ros2/rclcpp/issues/200
+- https://github.com/ros2/rclcpp/blob/96ebf59a6045a535730d98fff25e522807c7aa75/rclcpp/src/rclcpp/parameter_client.cpp#L412-L426
+
+**Suggested Action**: Throw an exception to indicate if something went wrong and document other expected conditions of the API.
+
+**Notes from on-line, post 2020-03-23 meeting**:
+
+- (tfoote) An empty list is not a valid response unless you passed in an empty list. The return should have the same length as the request in the same order. Any parameters that are not set should return a ParameterVariant with type PARAMETER_NOT_SET. to indicate that it was polled and determined to not be set. Suggested action improve documentation of the API to clarify a short or incomplete.
+- (jacobperron) I think throwing an exception is also a valid action, making it clear that an error occurred.
+- (wjwwood) Using exceptions to indicate an exceptional case (something went wrong) seems reasonable to me too.
+
+## Clock
+
+### Clock Jump callbacks on System or Steady time?
+
+> Currently time jump callbacks are registered via Clock::create_jump_handler(). Jump handlers are only invoked by TimeSource::set_clock(). This is only called if the clock type is RCL_ROS_TIME and ROS time is active.
+
+- https://github.com/ros2/rclcpp/issues/528
+
+**Suggested Action**: Document that time jumping is only detected with ROS time, consider a warning.
+
+**Notes from on-line, post 2020-03-23 meeting**:
+
+- (tfoote) There should be no jumps in steady time. If there's a big change in system time, it doesn't necessarily mean that time jumped, just that you might have been sleeping for a long time. Most ntp systems adjust the slew rate these days instead of jumping but still that's an external process and I don't know of any APIs to introspect the state of the clock. I'm not sure that we have a way to detect jumps in time for system or steady time. To that end I think that we should be clear that we only provide callbacks when simulation time starts or stops, or simulation time jumps. We should also strongly recommend that operators not actively adjust their system clocks while running ROS nodes.
+- (jacobperron) I agree with Tully, if we don't have a way to detect system time jumps then I think we should just document that this only works with ROS time. In addition to documentation, we could log an info or warning message if the user registers jump callback with steady or system time, but it may be unnecessarily noisy.
+

rclcpp/doc/notes_on_statically_typed_parameters.md

@@ -0,0 +1,141 @@
+# Notes on statically typed parameters
+
+## Introduction
+
+Until ROS 2 Foxy, all parameters could change type anytime, except if the user installed a parameter callback to reject a change.
+This could generate confusing errors, for example:
+
+```
+$ ros2 run demo_nodes_py listener &
+$ ros2 param set /listener use_sim_time not_a_boolean
+[ERROR] [1614712713.233733147] [listener]: use_sim_time parameter set to something besides a bool
+Set parameter successful
+$ ros2 param get /listener use_sim_time
+String value is: not_a_boolean
+```
+
+For most use cases, having static parameter types is enough.
+This article documents some of the decisions that were made when implementing static parameter types enforcement in:
+
+* https://github.com/ros2/rclcpp/pull/1522
+* https://github.com/ros2/rclpy/pull/683
+
+## Allowing dynamically typed parameters
+
+There might be some scenarios where dynamic typing is desired, so a `dynamic_typing` field was added to the [parameter descriptor](https://github.com/ros2/rcl_interfaces/blob/09b5ed93a733adb9deddc47f9a4a8c6e9f584667/rcl_interfaces/msg/ParameterDescriptor.msg#L25).
+It defaults to `false`.
+
+For example:
+
+```cpp
+rcl_interfaces::msg::ParameterDescriptor descriptor;
+descriptor.dynamic_typing = true;
+
+node->declare_parameter("dynamically_typed_parameter", rclcpp::ParameterValue{}, descriptor);
+```
+
+```py
+rcl_interfaces.msg.ParameterDescriptor descriptor;
+descriptor.dynamic_typing = True;
+
+node.declare_parameter("dynamically_typed_parameter", None, descriptor);
+```
+
+## How is the parameter type specified?
+
+The parameter type will be inferred from the default value provided when declaring it.
+
+## Statically typed parameters when allowing undeclared parameters
+
+When undeclared parameters are allowed and a parameter is set without a previous declaration, the parameter will be dynamically typed.
+This is consistent with other allowed behaviors when undeclared parameters are allowed, e.g. trying to get an undeclared parameter returns "NOT_SET".
+Parameter declarations will remain special and dynamic or static typing will be used based on the parameter descriptor (default to static).
+
+## Declaring a parameter without a default value
+
+There might be cases were a default value does not make sense and the user must always provide an override.
+In those cases, the parameter type can be specified explicitly:
+
+```cpp
+// method signature
+template<typename T>
+Node::declare_parameter<T>(std::string name, rcl_interfaces::msg::ParameterDescriptor = rcl_interfaces::msg::ParameterDescriptor{});
+// or alternatively
+Node::declare_parameter(std::string name, rclcpp::ParameterType type, rcl_interfaces::msg::ParameterDescriptor = rcl_interfaces::msg::ParameterDescriptor{});
+
+// examples
+node->declare_parameter<int64_t>("my_integer_parameter");  // declare an integer parameter
+node->declare_parameter("another_integer_parameter", rclcpp::ParameterType::PARAMETER_INTEGER);  // another way to do the same
+```
+
+```py
+# method signature
+Node.declare_parameter(name: str, param_type: rclpy.Parameter.Type, descriptor: rcl_interfaces.msg.ParameterDescriptor = rcl_interfaces.msg.ParameterDescriptor())
+
+# example
+node.declare_parameter('my_integer_parameter', rclpy.Parameter.Type.INTEGER);  # declare an integer parameter
+```
+
+If the parameter may be unused, but when used requires a parameter override, then you could conditionally declare it:
+
+```cpp
+auto mode = node->declare_parameter("mode", "modeA");  // "mode" parameter is an string
+if (mode == "modeB") {
+    node->declare_parameter<int64_t>("param_needed_when_mode_b");  // when "modeB", the user must provide "param_needed_when_mode_b"
+}
+```
+
+## Other migration notes
+
+Declaring a parameter with only a name is deprecated:
+
+```cpp
+node->declare_parameter("my_param");  // this generates a build warning
+```
+
+```py
+node.declare_parameter("my_param");  # this generates a python user warning
+```
+
+Before, you could initialize a parameter with the "NOT SET" value (in cpp `rclcpp::ParameterValue{}`, in python `None`).
+Now this will throw an exception in both cases:
+
+```cpp
+node->declare_parameter("my_param", rclcpp::ParameterValue{});  // not valid, will throw exception
+```
+
+```py
+node.declare_parameter("my_param", None);  # not valid, will raise error
+```
+
+## Possible improvements
+
+### Easier way to declare dynamically typed parameters
+
+Declaring a dynamically typed parameter in `rclcpp` could be considered to be a bit verbose:
+
+```cpp
+rcl_interfaces::msg::ParameterDescriptor descriptor;
+descriptor.dynamic_typing = true;
+
+node->declare_parameter(name, rclcpp::ParameterValue{}, descriptor);
+```
+
+the following ways could be supported to make it simpler:
+
+```cpp
+node->declare_parameter(name, rclcpp::PARAMETER_DYNAMIC);
+node->declare_parameter(name, default_value, rclcpp::PARAMETER_DYNAMIC);
+```
+
+or alternatively:
+
+```cpp
+node->declare_parameter(name, default_value, rclcpp::ParameterDescriptor{}.dynamic_typing());
+```
+
+For `rclpy`, there's already a short way to do it:
+
+```py
+node.declare_parameter(name, default_value, rclpy.ParameterDescriptor(dynamic_typing=true));
+```

rclcpp/include/rclcpp/allocator/allocator_common.hpp

@@ -15,6 +15,7 @@
 #ifndef RCLCPP__ALLOCATOR__ALLOCATOR_COMMON_HPP_
 #define RCLCPP__ALLOCATOR__ALLOCATOR_COMMON_HPP_
 
+#include <cstring>
 #include <memory>
 
 #include "rcl/allocator.h"
@@ -39,6 +40,22 @@ void * retyped_allocate(size_t size, void * untyped_allocator)
   return std::allocator_traits<Alloc>::allocate(*typed_allocator, size);
 }
 
+template<typename Alloc>
+void * retyped_zero_allocate(size_t number_of_elem, size_t size_of_elem, void * untyped_allocator)
+{
+  auto typed_allocator = static_cast<Alloc *>(untyped_allocator);
+  if (!typed_allocator) {
+    throw std::runtime_error("Received incorrect allocator type");
+  }
+  size_t size = number_of_elem * size_of_elem;
+  void * allocated_memory =
+    std::allocator_traits<Alloc>::allocate(*typed_allocator, size);
+  if (allocated_memory) {
+    std::memset(allocated_memory, 0, size);
+  }
+  return allocated_memory;
+}
+
 template<typename T, typename Alloc>
 void retyped_deallocate(void * untyped_pointer, void * untyped_allocator)
 {
@@ -73,6 +90,7 @@ rcl_allocator_t get_rcl_allocator(Alloc & allocator)
   rcl_allocator_t rcl_allocator = rcl_get_default_allocator();
 #ifndef _WIN32
   rcl_allocator.allocate = &retyped_allocate<Alloc>;
+  rcl_allocator.zero_allocate = &retyped_zero_allocate<Alloc>;
   rcl_allocator.deallocate = &retyped_deallocate<T, Alloc>;
   rcl_allocator.reallocate = &retyped_reallocate<T, Alloc>;
   rcl_allocator.state = &allocator;

rclcpp/include/rclcpp/allocator/allocator_deleter.hpp

@@ -41,7 +41,7 @@ public:
   }
 
   template<typename T>
-  AllocatorDeleter(const AllocatorDeleter<T> & a)
+  explicit AllocatorDeleter(const AllocatorDeleter<T> & a)
   {
     allocator_ = a.get_allocator();
   }
@@ -95,7 +95,7 @@ void set_allocator_for_deleter(AllocatorDeleter<T> * deleter, Alloc * alloc)
 template<typename Alloc, typename T>
 using Deleter = typename std::conditional<
   std::is_same<typename std::allocator_traits<Alloc>::template rebind_alloc<T>,
-  typename std::allocator<void>::template rebind<T>::other>::value,
+  std::allocator<T>>::value,
   std::default_delete<T>,
   AllocatorDeleter<Alloc>
   >::type;

rclcpp/include/rclcpp/any_executable.hpp

@@ -47,14 +47,9 @@ struct AnyExecutable
   // These are used to keep the scope on the containing items
   rclcpp::CallbackGroup::SharedPtr callback_group;
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base;
+  std::shared_ptr<void> data;
 };
 
-namespace executor
-{
-
-using AnyExecutable [[deprecated("use rclcpp::AnyExecutable instead")]] = AnyExecutable;
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__ANY_EXECUTABLE_HPP_

rclcpp/include/rclcpp/any_service_callback.hpp

@@ -15,10 +15,12 @@
 #ifndef RCLCPP__ANY_SERVICE_CALLBACK_HPP_
 #define RCLCPP__ANY_SERVICE_CALLBACK_HPP_
 
+#include <variant>
 #include <functional>
 #include <memory>
 #include <stdexcept>
 #include <type_traits>
+#include <utility>
 
 #include "rclcpp/function_traits.hpp"
 #include "rclcpp/visibility_control.hpp"
@@ -29,93 +31,204 @@
 namespace rclcpp
 {
 
+namespace detail
+{
+template<typename T, typename = void>
+struct can_be_nullptr : std::false_type {};
+
+// Some lambdas define a comparison with nullptr,
+// but we see a warning that they can never be null when using it.
+// We also test if `T &` can be assigned to `nullptr` to avoid the issue.
+template<typename T>
+#ifdef __QNXNTO__
+struct can_be_nullptr<T, std::void_t<
+    decltype(std::declval<T>() == nullptr)>>: std::true_type {};
+#else
+struct can_be_nullptr<T, std::void_t<
+    decltype(std::declval<T>() == nullptr), decltype(std::declval<T &>() = nullptr)>>
+  : std::true_type {};
+#endif
+}  // namespace detail
+
+// Forward declare
+template<typename ServiceT>
+class Service;
+
 template<typename ServiceT>
 class AnyServiceCallback
 {
-private:
-  using SharedPtrCallback = std::function<
-    void (
-      const std::shared_ptr<typename ServiceT::Request>,
-      std::shared_ptr<typename ServiceT::Response>
-    )>;
-  using SharedPtrWithRequestHeaderCallback = std::function<
-    void (
-      const std::shared_ptr<rmw_request_id_t>,
-      const std::shared_ptr<typename ServiceT::Request>,
-      std::shared_ptr<typename ServiceT::Response>
-    )>;
-
-  SharedPtrCallback shared_ptr_callback_;
-  SharedPtrWithRequestHeaderCallback shared_ptr_with_request_header_callback_;
-
 public:
   AnyServiceCallback()
-  : shared_ptr_callback_(nullptr), shared_ptr_with_request_header_callback_(nullptr)
+  : callback_(std::monostate{})
   {}
 
-  AnyServiceCallback(const AnyServiceCallback &) = default;
-
   template<
     typename CallbackT,
-    typename std::enable_if<
+    typename std::enable_if_t<!detail::can_be_nullptr<CallbackT>::value, int> = 0>
+  void
+  set(CallbackT && callback)
+  {
+    // Workaround Windows issue with std::bind
+    if constexpr (
       rclcpp::function_traits::same_arguments<
         CallbackT,
         SharedPtrCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
-  {
-    shared_ptr_callback_ = callback;
+      >::value)
+    {
+      callback_.template emplace<SharedPtrCallback>(callback);
+    } else if constexpr (  // NOLINT, can't satisfy both cpplint and uncrustify
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrWithRequestHeaderCallback
+      >::value)
+    {
+      callback_.template emplace<SharedPtrWithRequestHeaderCallback>(callback);
+    } else if constexpr (  // NOLINT
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrDeferResponseCallback
+      >::value)
+    {
+      callback_.template emplace<SharedPtrDeferResponseCallback>(callback);
+    } else if constexpr (  // NOLINT
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrDeferResponseCallbackWithServiceHandle
+      >::value)
+    {
+      callback_.template emplace<SharedPtrDeferResponseCallbackWithServiceHandle>(callback);
+    } else {
+      // the else clause is not needed, but anyways we should only be doing this instead
+      // of all the above workaround ...
+      callback_ = std::forward<CallbackT>(callback);
+    }
   }
 
   template<
     typename CallbackT,
-    typename std::enable_if<
+    typename std::enable_if_t<detail::can_be_nullptr<CallbackT>::value, int> = 0>
+  void
+  set(CallbackT && callback)
+  {
+    if (!callback) {
+      throw std::invalid_argument("AnyServiceCallback::set(): callback cannot be nullptr");
+    }
+    // Workaround Windows issue with std::bind
+    if constexpr (
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrCallback
+      >::value)
+    {
+      callback_.template emplace<SharedPtrCallback>(callback);
+    } else if constexpr (  // NOLINT
       rclcpp::function_traits::same_arguments<
         CallbackT,
         SharedPtrWithRequestHeaderCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
-  {
-    shared_ptr_with_request_header_callback_ = callback;
+      >::value)
+    {
+      callback_.template emplace<SharedPtrWithRequestHeaderCallback>(callback);
+    } else if constexpr (  // NOLINT
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrDeferResponseCallback
+      >::value)
+    {
+      callback_.template emplace<SharedPtrDeferResponseCallback>(callback);
+    } else if constexpr (  // NOLINT
+      rclcpp::function_traits::same_arguments<
+        CallbackT,
+        SharedPtrDeferResponseCallbackWithServiceHandle
+      >::value)
+    {
+      callback_.template emplace<SharedPtrDeferResponseCallbackWithServiceHandle>(callback);
+    } else {
+      // the else clause is not needed, but anyways we should only be doing this instead
+      // of all the above workaround ...
+      callback_ = std::forward<CallbackT>(callback);
+    }
   }
 
-  void dispatch(
-    std::shared_ptr<rmw_request_id_t> request_header,
-    std::shared_ptr<typename ServiceT::Request> request,
-    std::shared_ptr<typename ServiceT::Response> response)
+  // template<typename Allocator = std::allocator<typename ServiceT::Response>>
+  std::shared_ptr<typename ServiceT::Response>
+  dispatch(
+    const std::shared_ptr<rclcpp::Service<ServiceT>> & service_handle,
+    const std::shared_ptr<rmw_request_id_t> & request_header,
+    std::shared_ptr<typename ServiceT::Request> request)
   {
-    TRACEPOINT(callback_start, (const void *)this, false);
-    if (shared_ptr_callback_ != nullptr) {
-      (void)request_header;
-      shared_ptr_callback_(request, response);
-    } else if (shared_ptr_with_request_header_callback_ != nullptr) {
-      shared_ptr_with_request_header_callback_(request_header, request, response);
-    } else {
-      throw std::runtime_error("unexpected request without any callback set");
+    TRACEPOINT(callback_start, static_cast<const void *>(this), false);
+    if (std::holds_alternative<std::monostate>(callback_)) {
+      // TODO(ivanpauno): Remove the set method, and force the users of this class
+      // to pass a callback at construnciton.
+      throw std::runtime_error{"unexpected request without any callback set"};
     }
-    TRACEPOINT(callback_end, (const void *)this);
+    if (std::holds_alternative<SharedPtrDeferResponseCallback>(callback_)) {
+      const auto & cb = std::get<SharedPtrDeferResponseCallback>(callback_);
+      cb(request_header, std::move(request));
+      return nullptr;
+    }
+    if (std::holds_alternative<SharedPtrDeferResponseCallbackWithServiceHandle>(callback_)) {
+      const auto & cb = std::get<SharedPtrDeferResponseCallbackWithServiceHandle>(callback_);
+      cb(service_handle, request_header, std::move(request));
+      return nullptr;
+    }
+    // auto response = allocate_shared<typename ServiceT::Response, Allocator>();
+    auto response = std::make_shared<typename ServiceT::Response>();
+    if (std::holds_alternative<SharedPtrCallback>(callback_)) {
+      (void)request_header;
+      const auto & cb = std::get<SharedPtrCallback>(callback_);
+      cb(std::move(request), response);
+    } else if (std::holds_alternative<SharedPtrWithRequestHeaderCallback>(callback_)) {
+      const auto & cb = std::get<SharedPtrWithRequestHeaderCallback>(callback_);
+      cb(request_header, std::move(request), response);
+    }
+    TRACEPOINT(callback_end, static_cast<const void *>(this));
+    return response;
   }
 
   void register_callback_for_tracing()
   {
 #ifndef TRACETOOLS_DISABLED
-    if (shared_ptr_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        (const void *)this,
-        get_symbol(shared_ptr_callback_));
-    } else if (shared_ptr_with_request_header_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        (const void *)this,
-        get_symbol(shared_ptr_with_request_header_callback_));
-    }
+    std::visit(
+      [this](auto && arg) {
+        TRACEPOINT(
+          rclcpp_callback_register,
+          static_cast<const void *>(this),
+          tracetools::get_symbol(arg));
+      }, callback_);
 #endif  // TRACETOOLS_DISABLED
   }
+
+private:
+  using SharedPtrCallback = std::function<
+    void (
+      std::shared_ptr<typename ServiceT::Request>,
+      std::shared_ptr<typename ServiceT::Response>
+    )>;
+  using SharedPtrWithRequestHeaderCallback = std::function<
+    void (
+      std::shared_ptr<rmw_request_id_t>,
+      std::shared_ptr<typename ServiceT::Request>,
+      std::shared_ptr<typename ServiceT::Response>
+    )>;
+  using SharedPtrDeferResponseCallback = std::function<
+    void (
+      std::shared_ptr<rmw_request_id_t>,
+      std::shared_ptr<typename ServiceT::Request>
+    )>;
+  using SharedPtrDeferResponseCallbackWithServiceHandle = std::function<
+    void (
+      std::shared_ptr<rclcpp::Service<ServiceT>>,
+      std::shared_ptr<rmw_request_id_t>,
+      std::shared_ptr<typename ServiceT::Request>
+    )>;
+
+  std::variant<
+    std::monostate,
+    SharedPtrCallback,
+    SharedPtrWithRequestHeaderCallback,
+    SharedPtrDeferResponseCallback,
+    SharedPtrDeferResponseCallbackWithServiceHandle> callback_;
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/callback_group.hpp

@@ -16,11 +16,14 @@
 #define RCLCPP__CALLBACK_GROUP_HPP_
 
 #include <atomic>
+#include <functional>
+#include <memory>
 #include <mutex>
-#include <string>
 #include <vector>
 
 #include "rclcpp/client.hpp"
+#include "rclcpp/context.hpp"
+#include "rclcpp/guard_condition.hpp"
 #include "rclcpp/publisher_base.hpp"
 #include "rclcpp/service.hpp"
 #include "rclcpp/subscription_base.hpp"
@@ -56,8 +59,48 @@ class CallbackGroup
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(CallbackGroup)
 
+  /// Constructor for CallbackGroup.
+  /**
+   * Callback Groups have a type, either 'Mutually Exclusive' or 'Reentrant'
+   * and when creating one the type must be specified.
+   *
+   * Callbacks in Reentrant Callback Groups must be able to:
+   *   - run at the same time as themselves (reentrant)
+   *   - run at the same time as other callbacks in their group
+   *   - run at the same time as other callbacks in other groups
+   *
+   * Callbacks in Mutually Exclusive Callback Groups:
+   *   - will not be run multiple times simultaneously (non-reentrant)
+   *   - will not be run at the same time as other callbacks in their group
+   *   - but must run at the same time as callbacks in other groups
+   *
+   * Additionally, callback groups have a property which determines whether or
+   * not they are added to an executor with their associated node automatically.
+   * When creating a callback group the automatically_add_to_executor_with_node
+   * argument determines this behavior, and if true it will cause the newly
+   * created callback group to be added to an executor with the node when the
+   * Executor::add_node method is used.
+   * If false, this callback group will not be added automatically and would
+   * have to be added to an executor manually using the
+   * Executor::add_callback_group method.
+   *
+   * Whether the node was added to the executor before creating the callback
+   * group, or after, is irrelevant; the callback group will be automatically
+   * added to the executor in either case.
+   *
+   * \param[in] group_type The type of the callback group.
+   * \param[in] automatically_add_to_executor_with_node A boolean that
+   *   determines whether a callback group is automatically added to an executor
+   *   with the node with which it is associated.
+   */
   RCLCPP_PUBLIC
-  explicit CallbackGroup(CallbackGroupType group_type);
+  explicit CallbackGroup(
+    CallbackGroupType group_type,
+    bool automatically_add_to_executor_with_node = true);
+
+  /// Default destructor.
+  RCLCPP_PUBLIC
+  ~CallbackGroup();
 
   template<typename Function>
   rclcpp::SubscriptionBase::SharedPtr
@@ -102,6 +145,49 @@ public:
   const CallbackGroupType &
   type() const;
 
+  RCLCPP_PUBLIC
+  void collect_all_ptrs(
+    std::function<void(const rclcpp::SubscriptionBase::SharedPtr &)> sub_func,
+    std::function<void(const rclcpp::ServiceBase::SharedPtr &)> service_func,
+    std::function<void(const rclcpp::ClientBase::SharedPtr &)> client_func,
+    std::function<void(const rclcpp::TimerBase::SharedPtr &)> timer_func,
+    std::function<void(const rclcpp::Waitable::SharedPtr &)> waitable_func) const;
+
+  /// Return a reference to the 'associated with executor' atomic boolean.
+  /**
+   * When a callback group is added to an executor this boolean is checked
+   * to ensure it has not already been added to another executor.
+   * If it has not been, then this boolean is set to true to indicate it is
+   * now associated with an executor.
+   *
+   * When the callback group is removed from the executor, this atomic boolean
+   * is set back to false.
+   *
+   * \return the 'associated with executor' atomic boolean
+   */
+  RCLCPP_PUBLIC
+  std::atomic_bool &
+  get_associated_with_executor_atomic();
+
+  /// Return true if this callback group should be automatically added to an executor by the node.
+  /**
+   * \return boolean true if this callback group should be automatically added
+   *   to an executor when the associated node is added, otherwise false.
+   */
+  RCLCPP_PUBLIC
+  bool
+  automatically_add_to_executor_with_node() const;
+
+  /// Defer creating the notify guard condition and return it.
+  RCLCPP_PUBLIC
+  rclcpp::GuardCondition::SharedPtr
+  get_notify_guard_condition(const rclcpp::Context::SharedPtr context_ptr);
+
+  /// Trigger the notify guard condition.
+  RCLCPP_PUBLIC
+  void
+  trigger_notify_guard_condition();
+
 protected:
   RCLCPP_DISABLE_COPY(CallbackGroup)
 
@@ -136,12 +222,17 @@ protected:
   CallbackGroupType type_;
   // Mutex to protect the subsequent vectors of pointers.
   mutable std::mutex mutex_;
+  std::atomic_bool associated_with_executor_;
   std::vector<rclcpp::SubscriptionBase::WeakPtr> subscription_ptrs_;
   std::vector<rclcpp::TimerBase::WeakPtr> timer_ptrs_;
   std::vector<rclcpp::ServiceBase::WeakPtr> service_ptrs_;
   std::vector<rclcpp::ClientBase::WeakPtr> client_ptrs_;
   std::vector<rclcpp::Waitable::WeakPtr> waitable_ptrs_;
   std::atomic_bool can_be_taken_from_;
+  const bool automatically_add_to_executor_with_node_;
+  // defer the creation of the guard condition
+  std::shared_ptr<rclcpp::GuardCondition> notify_guard_condition_ = nullptr;
+  std::recursive_mutex notify_guard_condition_mutex_;
 
 private:
   template<typename TypeT, typename Function>
@@ -159,13 +250,6 @@ private:
   }
 };
 
-namespace callback_group
-{
-
-using CallbackGroupType [[deprecated("use rclcpp::CallbackGroupType instead")]] = CallbackGroupType;
-using CallbackGroup [[deprecated("use rclcpp::CallbackGroup instead")]] = CallbackGroup;
-
-}  // namespace callback_group
 }  // namespace rclcpp
 
 #endif  // RCLCPP__CALLBACK_GROUP_HPP_

rclcpp/include/rclcpp/client.hpp

@@ -17,34 +17,103 @@
 
 #include <atomic>
 #include <future>
-#include <map>
+#include <unordered_map>
 #include <memory>
+#include <mutex>
+#include <optional>  // NOLINT, cpplint doesn't think this is a cpp std header
 #include <sstream>
 #include <string>
 #include <tuple>
 #include <utility>
+#include <variant>  // NOLINT
+#include <vector>
 
 #include "rcl/client.h"
 #include "rcl/error_handling.h"
+#include "rcl/event_callback.h"
 #include "rcl/wait.h"
 
+#include "rclcpp/detail/cpp_callback_trampoline.hpp"
 #include "rclcpp/exceptions.hpp"
+#include "rclcpp/expand_topic_or_service_name.hpp"
 #include "rclcpp/function_traits.hpp"
+#include "rclcpp/logging.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_graph_interface.hpp"
+#include "rclcpp/qos.hpp"
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/utilities.hpp"
-#include "rclcpp/expand_topic_or_service_name.hpp"
 #include "rclcpp/visibility_control.hpp"
 
-#include "rcutils/logging_macros.h"
-
 #include "rmw/error_handling.h"
+#include "rmw/impl/cpp/demangle.hpp"
 #include "rmw/rmw.h"
 
 namespace rclcpp
 {
 
+namespace detail
+{
+template<typename FutureT>
+struct FutureAndRequestId
+{
+  FutureT future;
+  int64_t request_id;
+
+  FutureAndRequestId(FutureT impl, int64_t req_id)
+  : future(std::move(impl)), request_id(req_id)
+  {}
+
+  /// Allow implicit conversions to `std::future` by reference.
+  operator FutureT &() {return this->future;}
+
+  /// Deprecated, use the `future` member variable instead.
+  /**
+   * Allow implicit conversions to `std::future` by value.
+   * \deprecated
+   */
+  [[deprecated("FutureAndRequestId: use .future instead of an implicit conversion")]]
+  operator FutureT() {return this->future;}
+
+  // delegate future like methods in the std::future impl_
+
+  /// See std::future::get().
+  auto get() {return this->future.get();}
+  /// See std::future::valid().
+  bool valid() const noexcept {return this->future.valid();}
+  /// See std::future::wait().
+  void wait() const {return this->future.wait();}
+  /// See std::future::wait_for().
+  template<class Rep, class Period>
+  std::future_status wait_for(
+    const std::chrono::duration<Rep, Period> & timeout_duration) const
+  {
+    return this->future.wait_for(timeout_duration);
+  }
+  /// See std::future::wait_until().
+  template<class Clock, class Duration>
+  std::future_status wait_until(
+    const std::chrono::time_point<Clock, Duration> & timeout_time) const
+  {
+    return this->future.wait_until(timeout_time);
+  }
+
+  // Rule of five, we could use the rule of zero here, but better be explicit as some of the
+  // methods are deleted.
+
+  /// Move constructor.
+  FutureAndRequestId(FutureAndRequestId && other) noexcept = default;
+  /// Deleted copy constructor, each instance is a unique owner of the future.
+  FutureAndRequestId(const FutureAndRequestId & other) = delete;
+  /// Move assignment.
+  FutureAndRequestId & operator=(FutureAndRequestId && other) noexcept = default;
+  /// Deleted copy assignment, each instance is a unique owner of the future.
+  FutureAndRequestId & operator=(const FutureAndRequestId & other) = delete;
+  /// Destructor.
+  ~FutureAndRequestId() = default;
+};
+}  // namespace detail
+
 namespace node_interfaces
 {
 class NodeBaseInterface;
@@ -84,22 +153,43 @@ public:
   bool
   take_type_erased_response(void * response_out, rmw_request_id_t & request_header_out);
 
+  /// Return the name of the service.
+  /** \return The name of the service. */
   RCLCPP_PUBLIC
   const char *
   get_service_name() const;
 
+  /// Return the rcl_client_t client handle in a std::shared_ptr.
+  /**
+   * This handle remains valid after the Client is destroyed.
+   * The actual rcl client is not finalized until it is out of scope everywhere.
+   */
   RCLCPP_PUBLIC
   std::shared_ptr<rcl_client_t>
   get_client_handle();
 
+  /// Return the rcl_client_t client handle in a std::shared_ptr.
+  /**
+   * This handle remains valid after the Client is destroyed.
+   * The actual rcl client is not finalized until it is out of scope everywhere.
+   */
   RCLCPP_PUBLIC
   std::shared_ptr<const rcl_client_t>
   get_client_handle() const;
 
+  /// Return if the service is ready.
+  /**
+   * \return `true` if the service is ready, `false` otherwise
+   */
   RCLCPP_PUBLIC
   bool
   service_is_ready() const;
 
+  /// Wait for a service to be ready.
+  /**
+   * \param timeout maximum time to wait
+   * \return `true` if the service is ready and the timeout is not over, `false` otherwise
+   */
   template<typename RepT = int64_t, typename RatioT = std::milli>
   bool
   wait_for_service(
@@ -129,6 +219,122 @@ public:
   bool
   exchange_in_use_by_wait_set_state(bool in_use_state);
 
+  /// Get the actual request publsher QoS settings, after the defaults have been determined.
+  /**
+   * The actual configuration applied when using RMW_QOS_POLICY_*_SYSTEM_DEFAULT
+   * can only be resolved after the creation of the client, and it
+   * depends on the underlying rmw implementation.
+   * If the underlying setting in use can't be represented in ROS terms,
+   * it will be set to RMW_QOS_POLICY_*_UNKNOWN.
+   * May throw runtime_error when an unexpected error occurs.
+   *
+   * \return The actual request publsher qos settings.
+   * \throws std::runtime_error if failed to get qos settings
+   */
+  RCLCPP_PUBLIC
+  rclcpp::QoS
+  get_request_publisher_actual_qos() const;
+
+  /// Get the actual response subscription QoS settings, after the defaults have been determined.
+  /**
+   * The actual configuration applied when using RMW_QOS_POLICY_*_SYSTEM_DEFAULT
+   * can only be resolved after the creation of the client, and it
+   * depends on the underlying rmw implementation.
+   * If the underlying setting in use can't be represented in ROS terms,
+   * it will be set to RMW_QOS_POLICY_*_UNKNOWN.
+   * May throw runtime_error when an unexpected error occurs.
+   *
+   * \return The actual response subscription qos settings.
+   * \throws std::runtime_error if failed to get qos settings
+   */
+  RCLCPP_PUBLIC
+  rclcpp::QoS
+  get_response_subscription_actual_qos() const;
+
+  /// Set a callback to be called when each new response is received.
+  /**
+   * The callback receives a size_t which is the number of responses received
+   * since the last time this callback was called.
+   * Normally this is 1, but can be > 1 if responses were received before any
+   * callback was set.
+   *
+   * Since this callback is called from the middleware, you should aim to make
+   * it fast and not blocking.
+   * If you need to do a lot of work or wait for some other event, you should
+   * spin it off to another thread, otherwise you risk blocking the middleware.
+   *
+   * Calling it again will clear any previously set callback.
+   *
+   * An exception will be thrown if the callback is not callable.
+   *
+   * This function is thread-safe.
+   *
+   * If you want more information available in the callback, like the client
+   * or other information, you may use a lambda with captures or std::bind.
+   *
+   * \sa rmw_client_set_on_new_response_callback
+   * \sa rcl_client_set_on_new_response_callback
+   *
+   * \param[in] callback functor to be called when a new response is received
+   */
+  void
+  set_on_new_response_callback(std::function<void(size_t)> callback)
+  {
+    if (!callback) {
+      throw std::invalid_argument(
+              "The callback passed to set_on_new_response_callback "
+              "is not callable.");
+    }
+
+    auto new_callback =
+      [callback, this](size_t number_of_responses) {
+        try {
+          callback(number_of_responses);
+        } catch (const std::exception & exception) {
+          RCLCPP_ERROR_STREAM(
+            node_logger_,
+            "rclcpp::ClientBase@" << this <<
+              " caught " << rmw::impl::cpp::demangle(exception) <<
+              " exception in user-provided callback for the 'on new response' callback: " <<
+              exception.what());
+        } catch (...) {
+          RCLCPP_ERROR_STREAM(
+            node_logger_,
+            "rclcpp::ClientBase@" << this <<
+              " caught unhandled exception in user-provided callback " <<
+              "for the 'on new response' callback");
+        }
+      };
+
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+
+    // Set it temporarily to the new callback, while we replace the old one.
+    // This two-step setting, prevents a gap where the old std::function has
+    // been replaced but the middleware hasn't been told about the new one yet.
+    set_on_new_response_callback(
+      rclcpp::detail::cpp_callback_trampoline<const void *, size_t>,
+      static_cast<const void *>(&new_callback));
+
+    // Store the std::function to keep it in scope, also overwrites the existing one.
+    on_new_response_callback_ = new_callback;
+
+    // Set it again, now using the permanent storage.
+    set_on_new_response_callback(
+      rclcpp::detail::cpp_callback_trampoline<const void *, size_t>,
+      static_cast<const void *>(&on_new_response_callback_));
+  }
+
+  /// Unset the callback registered for new responses, if any.
+  void
+  clear_on_new_response_callback()
+  {
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+    if (on_new_response_callback_) {
+      set_on_new_response_callback(nullptr, nullptr);
+      on_new_response_callback_ = nullptr;
+    }
+  }
+
 protected:
   RCLCPP_DISABLE_COPY(ClientBase)
 
@@ -144,19 +350,30 @@ protected:
   const rcl_node_t *
   get_rcl_node_handle() const;
 
+  RCLCPP_PUBLIC
+  void
+  set_on_new_response_callback(rcl_event_callback_t callback, const void * user_data);
+
   rclcpp::node_interfaces::NodeGraphInterface::WeakPtr node_graph_;
   std::shared_ptr<rcl_node_t> node_handle_;
   std::shared_ptr<rclcpp::Context> context_;
+  rclcpp::Logger node_logger_;
 
   std::shared_ptr<rcl_client_t> client_handle_;
 
   std::atomic<bool> in_use_by_wait_set_{false};
+
+  std::recursive_mutex callback_mutex_;
+  std::function<void(size_t)> on_new_response_callback_{nullptr};
 };
 
 template<typename ServiceT>
 class Client : public ClientBase
 {
 public:
+  using Request = typename ServiceT::Request;
+  using Response = typename ServiceT::Response;
+
   using SharedRequest = typename ServiceT::Request::SharedPtr;
   using SharedResponse = typename ServiceT::Response::SharedPtr;
 
@@ -166,6 +383,7 @@ public:
   using SharedPromise = std::shared_ptr<Promise>;
   using SharedPromiseWithRequest = std::shared_ptr<PromiseWithRequest>;
 
+  using Future = std::future<SharedResponse>;
   using SharedFuture = std::shared_future<SharedResponse>;
   using SharedFutureWithRequest = std::shared_future<std::pair<SharedRequest, SharedResponse>>;
 
@@ -174,6 +392,75 @@ public:
 
   RCLCPP_SMART_PTR_DEFINITIONS(Client)
 
+  /// A convenient Client::Future and request id pair.
+  /**
+   * Public members:
+   * - future: a std::future<SharedResponse>.
+   * - request_id: the request id associated with the future.
+   *
+   * All the other methods are equivalent to the ones std::future provides.
+   */
+  struct FutureAndRequestId
+    : detail::FutureAndRequestId<std::future<SharedResponse>>
+  {
+    using detail::FutureAndRequestId<std::future<SharedResponse>>::FutureAndRequestId;
+
+    /// Deprecated, use `.future.share()` instead.
+    /**
+     * Allow implicit conversions to `std::shared_future` by value.
+     * \deprecated
+     */
+    [[deprecated(
+      "FutureAndRequestId: use .future.share() instead of an implicit conversion")]]
+    operator SharedFuture() {return this->future.share();}
+
+    // delegate future like methods in the std::future impl_
+
+    /// See std::future::share().
+    SharedFuture share() noexcept {return this->future.share();}
+  };
+
+  /// A convenient Client::SharedFuture and request id pair.
+  /**
+   * Public members:
+   * - future: a std::shared_future<SharedResponse>.
+   * - request_id: the request id associated with the future.
+   *
+   * All the other methods are equivalent to the ones std::shared_future provides.
+   */
+  struct SharedFutureAndRequestId
+    : detail::FutureAndRequestId<std::shared_future<SharedResponse>>
+  {
+    using detail::FutureAndRequestId<std::shared_future<SharedResponse>>::FutureAndRequestId;
+  };
+
+  /// A convenient Client::SharedFutureWithRequest and request id pair.
+  /**
+   * Public members:
+   * - future: a std::shared_future<SharedResponse>.
+   * - request_id: the request id associated with the future.
+   *
+   * All the other methods are equivalent to the ones std::shared_future provides.
+   */
+  struct SharedFutureWithRequestAndRequestId
+    : detail::FutureAndRequestId<std::shared_future<std::pair<SharedRequest, SharedResponse>>>
+  {
+    using detail::FutureAndRequestId<
+      std::shared_future<std::pair<SharedRequest, SharedResponse>>
+    >::FutureAndRequestId;
+  };
+
+  /// Default constructor.
+  /**
+   * The constructor for a Client is almost never called directly.
+   * Instead, clients should be instantiated through the function
+   * rclcpp::create_client().
+   *
+   * \param[in] node_base NodeBaseInterface pointer that is used in part of the setup.
+   * \param[in] node_graph The node graph interface of the corresponding node.
+   * \param[in] service_name Name of the topic to publish to.
+   * \param[in] client_options options for the subscription.
+   */
   Client(
     rclcpp::node_interfaces::NodeBaseInterface * node_base,
     rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph,
@@ -228,12 +515,20 @@ public:
     return this->take_type_erased_response(&response_out, request_header_out);
   }
 
+  /// Create a shared pointer with the response type
+  /**
+   * \return shared pointer with the response type
+   */
   std::shared_ptr<void>
   create_response() override
   {
     return std::shared_ptr<void>(new typename ServiceT::Response());
   }
 
+  /// Create a shared pointer with a rmw_request_id_t
+  /**
+   * \return shared pointer with a rmw_request_id_t
+   */
   std::shared_ptr<rmw_request_id_t>
   create_request_header() override
   {
@@ -242,39 +537,99 @@ public:
     return std::shared_ptr<rmw_request_id_t>(new rmw_request_id_t);
   }
 
+  /// Handle a server response
+  /**
+    * \param[in] request_header used to check if the secuence number is valid
+    * \param[in] response message with the server response
+   */
   void
   handle_response(
     std::shared_ptr<rmw_request_id_t> request_header,
     std::shared_ptr<void> response) override
   {
-    std::unique_lock<std::mutex> lock(pending_requests_mutex_);
-    auto typed_response = std::static_pointer_cast<typename ServiceT::Response>(response);
-    int64_t sequence_number = request_header->sequence_number;
-    // TODO(esteve) this should throw instead since it is not expected to happen in the first place
-    if (this->pending_requests_.count(sequence_number) == 0) {
-      RCUTILS_LOG_ERROR_NAMED(
-        "rclcpp",
-        "Received invalid sequence number. Ignoring...");
+    std::optional<CallbackInfoVariant>
+    optional_pending_request = this->get_and_erase_pending_request(request_header->sequence_number);
+    if (!optional_pending_request) {
       return;
     }
-    auto tuple = this->pending_requests_[sequence_number];
-    auto call_promise = std::get<0>(tuple);
-    auto callback = std::get<1>(tuple);
-    auto future = std::get<2>(tuple);
-    this->pending_requests_.erase(sequence_number);
-    // Unlock here to allow the service to be called recursively from one of its callbacks.
-    lock.unlock();
-
-    call_promise->set_value(typed_response);
-    callback(future);
+    auto & value = *optional_pending_request;
+    auto typed_response = std::static_pointer_cast<typename ServiceT::Response>(
+      std::move(response));
+    if (std::holds_alternative<Promise>(value)) {
+      auto & promise = std::get<Promise>(value);
+      promise.set_value(std::move(typed_response));
+    } else if (std::holds_alternative<CallbackTypeValueVariant>(value)) {
+      auto & inner = std::get<CallbackTypeValueVariant>(value);
+      const auto & callback = std::get<CallbackType>(inner);
+      auto & promise = std::get<Promise>(inner);
+      auto & future = std::get<SharedFuture>(inner);
+      promise.set_value(std::move(typed_response));
+      callback(std::move(future));
+    } else if (std::holds_alternative<CallbackWithRequestTypeValueVariant>(value)) {
+      auto & inner = std::get<CallbackWithRequestTypeValueVariant>(value);
+      const auto & callback = std::get<CallbackWithRequestType>(inner);
+      auto & promise = std::get<PromiseWithRequest>(inner);
+      auto & future = std::get<SharedFutureWithRequest>(inner);
+      auto & request = std::get<SharedRequest>(inner);
+      promise.set_value(std::make_pair(std::move(request), std::move(typed_response)));
+      callback(std::move(future));
+    }
   }
 
-  SharedFuture
+  /// Send a request to the service server.
+  /**
+   * This method returns a `FutureAndRequestId` instance
+   * that can be passed to Executor::spin_until_future_complete() to
+   * wait until it has been completed.
+   *
+   * If the future never completes,
+   * e.g. the call to Executor::spin_until_future_complete() times out,
+   * Client::remove_pending_request() must be called to clean the client internal state.
+   * Not doing so will make the `Client` instance to use more memory each time a response is not
+   * received from the service server.
+   *
+   * ```cpp
+   * auto future = client->async_send_request(my_request);
+   * if (
+   *   rclcpp::FutureReturnCode::TIMEOUT ==
+   *   executor->spin_until_future_complete(future, timeout))
+   * {
+   *   client->remove_pending_request(future);
+   *   // handle timeout
+   * } else {
+   *   handle_response(future.get());
+   * }
+   * ```
+   *
+   * \param[in] request request to be send.
+   * \return a FutureAndRequestId instance.
+   */
+  FutureAndRequestId
   async_send_request(SharedRequest request)
   {
-    return async_send_request(request, [](SharedFuture) {});
+    Promise promise;
+    auto future = promise.get_future();
+    auto req_id = async_send_request_impl(
+      *request,
+      std::move(promise));
+    return FutureAndRequestId(std::move(future), req_id);
   }
 
+  /// Send a request to the service server and schedule a callback in the executor.
+  /**
+   * Similar to the previous overload, but a callback will automatically be called when a response is received.
+   *
+   * If the callback is never called, because we never got a reply for the service server, remove_pending_request()
+   * has to be called with the returned request id or prune_pending_requests().
+   * Not doing so will make the `Client` instance use more memory each time a response is not
+   * received from the service server.
+   * In this case, it's convenient to setup a timer to cleanup the pending requests.
+   * See for example the `examples_rclcpp_async_client` package in https://github.com/ros2/examples.
+   *
+   * \param[in] request request to be send.
+   * \param[in] cb callback that will be called when we get a response for this request.
+   * \return the request id representing the request just sent.
+   */
   template<
     typename CallbackT,
     typename std::enable_if<
@@ -284,23 +639,28 @@ public:
       >::value
     >::type * = nullptr
   >
-  SharedFuture
+  SharedFutureAndRequestId
   async_send_request(SharedRequest request, CallbackT && cb)
   {
-    std::lock_guard<std::mutex> lock(pending_requests_mutex_);
-    int64_t sequence_number;
-    rcl_ret_t ret = rcl_send_request(get_client_handle().get(), request.get(), &sequence_number);
-    if (RCL_RET_OK != ret) {
-      rclcpp::exceptions::throw_from_rcl_error(ret, "failed to send request");
-    }
-
-    SharedPromise call_promise = std::make_shared<Promise>();
-    SharedFuture f(call_promise->get_future());
-    pending_requests_[sequence_number] =
-      std::make_tuple(call_promise, std::forward<CallbackType>(cb), f);
-    return f;
+    Promise promise;
+    auto shared_future = promise.get_future().share();
+    auto req_id = async_send_request_impl(
+      *request,
+      std::make_tuple(
+        CallbackType{std::forward<CallbackT>(cb)},
+        shared_future,
+        std::move(promise)));
+    return SharedFutureAndRequestId{std::move(shared_future), req_id};
   }
 
+  /// Send a request to the service server and schedule a callback in the executor.
+  /**
+   * Similar to the previous method, but you can get both the request and response in the callback.
+   *
+   * \param[in] request request to be send.
+   * \param[in] cb callback that will be called when we get a response for this request.
+   * \return the request id representing the request just sent.
+   */
   template<
     typename CallbackT,
     typename std::enable_if<
@@ -310,27 +670,165 @@ public:
       >::value
     >::type * = nullptr
   >
-  SharedFutureWithRequest
+  SharedFutureWithRequestAndRequestId
   async_send_request(SharedRequest request, CallbackT && cb)
   {
-    SharedPromiseWithRequest promise = std::make_shared<PromiseWithRequest>();
-    SharedFutureWithRequest future_with_request(promise->get_future());
-
-    auto wrapping_cb = [future_with_request, promise, request, &cb](SharedFuture future) {
-        auto response = future.get();
-        promise->set_value(std::make_pair(request, response));
-        cb(future_with_request);
-      };
-
-    async_send_request(request, wrapping_cb);
-
-    return future_with_request;
+    PromiseWithRequest promise;
+    auto shared_future = promise.get_future().share();
+    auto req_id = async_send_request_impl(
+      *request,
+      std::make_tuple(
+        CallbackWithRequestType{std::forward<CallbackT>(cb)},
+        request,
+        shared_future,
+        std::move(promise)));
+    return SharedFutureWithRequestAndRequestId{std::move(shared_future), req_id};
+  }
+
+  /// Cleanup a pending request.
+  /**
+   * This notifies the client that we have waited long enough for a response from the server
+   * to come, we have given up and we are not waiting for a response anymore.
+   *
+   * Not calling this will make the client start using more memory for each request
+   * that never got a reply from the server.
+   *
+   * \param[in] request_id request id returned by async_send_request().
+   * \return true when a pending request was removed, false if not (e.g. a response was received).
+   */
+  bool
+  remove_pending_request(int64_t request_id)
+  {
+    std::lock_guard guard(pending_requests_mutex_);
+    return pending_requests_.erase(request_id) != 0u;
+  }
+
+  /// Cleanup a pending request.
+  /**
+   * Convenient overload, same as:
+   *
+   * `Client::remove_pending_request(this, future.request_id)`.
+   */
+  bool
+  remove_pending_request(const FutureAndRequestId & future)
+  {
+    return this->remove_pending_request(future.request_id);
+  }
+
+  /// Cleanup a pending request.
+  /**
+   * Convenient overload, same as:
+   *
+   * `Client::remove_pending_request(this, future.request_id)`.
+   */
+  bool
+  remove_pending_request(const SharedFutureAndRequestId & future)
+  {
+    return this->remove_pending_request(future.request_id);
+  }
+
+  /// Cleanup a pending request.
+  /**
+   * Convenient overload, same as:
+   *
+   * `Client::remove_pending_request(this, future.request_id)`.
+   */
+  bool
+  remove_pending_request(const SharedFutureWithRequestAndRequestId & future)
+  {
+    return this->remove_pending_request(future.request_id);
+  }
+
+  /// Clean all pending requests.
+  /**
+   * \return number of pending requests that were removed.
+   */
+  size_t
+  prune_pending_requests()
+  {
+    std::lock_guard guard(pending_requests_mutex_);
+    auto ret = pending_requests_.size();
+    pending_requests_.clear();
+    return ret;
+  }
+
+  /// Clean all pending requests older than a time_point.
+  /**
+   * \param[in] time_point Requests that were sent before this point are going to be removed.
+   * \param[inout] pruned_requests Removed requests id will be pushed to the vector
+   *  if a pointer is provided.
+   * \return number of pending requests that were removed.
+   */
+  template<typename AllocatorT = std::allocator<int64_t>>
+  size_t
+  prune_requests_older_than(
+    std::chrono::time_point<std::chrono::system_clock> time_point,
+    std::vector<int64_t, AllocatorT> * pruned_requests = nullptr)
+  {
+    std::lock_guard guard(pending_requests_mutex_);
+    auto old_size = pending_requests_.size();
+    for (auto it = pending_requests_.begin(), last = pending_requests_.end(); it != last; ) {
+      if (it->second.first < time_point) {
+        if (pruned_requests) {
+          pruned_requests->push_back(it->first);
+        }
+        it = pending_requests_.erase(it);
+      } else {
+        ++it;
+      }
+    }
+    return old_size - pending_requests_.size();
+  }
+
+protected:
+  using CallbackTypeValueVariant = std::tuple<CallbackType, SharedFuture, Promise>;
+  using CallbackWithRequestTypeValueVariant = std::tuple<
+    CallbackWithRequestType, SharedRequest, SharedFutureWithRequest, PromiseWithRequest>;
+
+  using CallbackInfoVariant = std::variant<
+    std::promise<SharedResponse>,
+    CallbackTypeValueVariant,
+    CallbackWithRequestTypeValueVariant>;
+
+  int64_t
+  async_send_request_impl(const Request & request, CallbackInfoVariant value)
+  {
+    int64_t sequence_number;
+    std::lock_guard<std::mutex> lock(pending_requests_mutex_);
+    rcl_ret_t ret = rcl_send_request(get_client_handle().get(), &request, &sequence_number);
+    if (RCL_RET_OK != ret) {
+      rclcpp::exceptions::throw_from_rcl_error(ret, "failed to send request");
+    }
+    pending_requests_.try_emplace(
+      sequence_number,
+      std::make_pair(std::chrono::system_clock::now(), std::move(value)));
+    return sequence_number;
+  }
+
+  std::optional<CallbackInfoVariant>
+  get_and_erase_pending_request(int64_t request_number)
+  {
+    std::unique_lock<std::mutex> lock(pending_requests_mutex_);
+    auto it = this->pending_requests_.find(request_number);
+    if (it == this->pending_requests_.end()) {
+      RCUTILS_LOG_DEBUG_NAMED(
+        "rclcpp",
+        "Received invalid sequence number. Ignoring...");
+      return std::nullopt;
+    }
+    std::optional<CallbackInfoVariant> value = std::move(it->second.second);
+    this->pending_requests_.erase(request_number);
+    return value;
   }
 
-private:
   RCLCPP_DISABLE_COPY(Client)
 
-  std::map<int64_t, std::tuple<SharedPromise, CallbackType, SharedFuture>> pending_requests_;
+  std::unordered_map<
+    int64_t,
+    std::pair<
+      std::chrono::time_point<std::chrono::system_clock>,
+      CallbackInfoVariant>>
+  pending_requests_;
   std::mutex pending_requests_mutex_;
 };
 

rclcpp/include/rclcpp/clock.hpp

@@ -19,6 +19,7 @@
 #include <memory>
 #include <mutex>
 
+#include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/time.hpp"
 #include "rclcpp/visibility_control.hpp"
@@ -59,6 +60,13 @@ public:
   /**
    * Initializes the clock instance with the given clock_type.
    *
+   * WARNING Don't instantiate a clock using RCL_ROS_TIME directly,
+   * unless you really know what you are doing. By default no TimeSource
+   * is attached to a new clock. This will lead to the unexpected behavior,
+   * that your RCL_ROS_TIME will run always on system time. If you want
+   * a RCL_ROS_TIME use Node::get_clock(), or make sure to attach a
+   * TimeSource yourself.
+   *
    * \param clock_type type of the clock.
    * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
    */
@@ -78,6 +86,109 @@ public:
   Time
   now();
 
+  /**
+   * Sleep until a specified Time, according to clock type.
+   *
+   * Notes for RCL_ROS_TIME clock type:
+   *   - Can sleep forever if ros time is active and received clock never reaches `until`
+   *   - If ROS time enabled state changes during the sleep, this method will immediately return
+   *     false. There is not a consistent choice of sleeping time when the time source changes,
+   *     so this is up to the caller to call again if needed.
+   *
+   * \warning When using gcc < 10 or when using gcc >= 10 and pthreads lacks the function
+   *    `pthread_cond_clockwait`, steady clocks may sleep using the system clock.
+   *    If so, steady clock sleep times can be affected by system clock time jumps.
+   *    Depending on the steady clock's epoch and resolution in comparison to the system clock's,
+   *    an overflow when converting steady clock durations to system clock times may cause
+   *    undefined behavior.
+   *    For more info see these issues:
+   *    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41861
+   *    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58931
+   *
+   * \param until absolute time according to current clock type to sleep until.
+   * \param context the rclcpp context the clock should use to check that ROS is still initialized.
+   * \return true immediately if `until` is in the past
+   * \return true when the time `until` is reached
+   * \return false if time cannot be reached reliably, for example from shutdown or a change
+   *    of time source.
+   * \throws std::runtime_error if the context is invalid
+   * \throws std::runtime_error if `until` has a different clock type from this clock
+   */
+  RCLCPP_PUBLIC
+  bool
+  sleep_until(
+    Time until,
+    Context::SharedPtr context = contexts::get_global_default_context());
+
+  /**
+   * Sleep for a specified Duration.
+   *
+   * Equivalent to
+   *
+   * ```cpp
+   * clock->sleep_until(clock->now() + rel_time, context)
+   * ```
+   *
+   * The function will return immediately if `rel_time` is zero or negative.
+   *
+   * \param rel_time the length of time to sleep for.
+   * \param context the rclcpp context the clock should use to check that ROS is still initialized.
+   * \return true when the end time is reached
+   * \return false if time cannot be reached reliably, for example from shutdown or a change
+   *    of time source.
+   * \throws std::runtime_error if the context is invalid
+   */
+  RCLCPP_PUBLIC
+  bool
+  sleep_for(
+    Duration rel_time,
+    Context::SharedPtr context = contexts::get_global_default_context());
+
+  /**
+   * Check if the clock is started.
+   *
+   * A started clock is a clock that reflects non-zero time.
+   * Typically a clock will be unstarted if it is using RCL_ROS_TIME with ROS time and
+   * nothing has been published on the clock topic yet.
+   *
+   * \return true if clock is started
+   * \throws std::runtime_error if the clock is not rcl_clock_valid
+   */
+  RCLCPP_PUBLIC
+  bool
+  started();
+
+  /**
+   * Wait until clock to start.
+   *
+   * \rclcpp::Clock::started
+   * \param context the context to wait in
+   * \return true if clock was already started or became started
+   * \throws std::runtime_error if the context is invalid or clock is not rcl_clock_valid
+   */
+  RCLCPP_PUBLIC
+  bool
+  wait_until_started(Context::SharedPtr context = contexts::get_global_default_context());
+
+  /**
+   * Wait for clock to start, with timeout.
+   *
+   * The timeout is waited in steady time.
+   *
+   * \rclcpp::Clock::started
+   * \param timeout the maximum time to wait for.
+   * \param context the context to wait in.
+   * \param wait_tick_ns the time to wait between each iteration of the wait loop (in nanoseconds).
+   * \return true if clock was or became valid
+   * \throws std::runtime_error if the context is invalid or clock is not rcl_clock_valid
+   */
+  RCLCPP_PUBLIC
+  bool
+  wait_until_started(
+    const rclcpp::Duration & timeout,
+    Context::SharedPtr context = contexts::get_global_default_context(),
+    const rclcpp::Duration & wait_tick_ns = rclcpp::Duration(0, static_cast<uint32_t>(1e7)));
+
   /**
    * Returns the clock of the type `RCL_ROS_TIME` is active.
    *
@@ -89,6 +200,7 @@ public:
   bool
   ros_time_is_active();
 
+  /// Return the rcl_clock_t clock handle
   RCLCPP_PUBLIC
   rcl_clock_t *
   get_clock_handle() noexcept;
@@ -97,6 +209,7 @@ public:
   rcl_clock_type_t
   get_clock_type() const noexcept;
 
+  /// Get the clock's mutex
   RCLCPP_PUBLIC
   std::mutex &
   get_clock_mutex() noexcept;
@@ -113,9 +226,9 @@ public:
    *
    * Function is only applicable if the clock_type is `RCL_ROS_TIME`
    *
-   * \param pre_callback. Must be non-throwing
-   * \param post_callback. Must be non-throwing.
-   * \param threshold. Callbacks will be triggered if the time jump is greater
+   * \param pre_callback Must be non-throwing
+   * \param post_callback Must be non-throwing.
+   * \param threshold Callbacks will be triggered if the time jump is greater
    * then the threshold.
    * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
    * \throws std::bad_alloc if the allocation of the JumpHandler fails.
@@ -134,7 +247,7 @@ private:
   RCLCPP_PUBLIC
   static void
   on_time_jump(
-    const struct rcl_time_jump_t * time_jump,
+    const rcl_time_jump_t * time_jump,
     bool before_jump,
     void * user_data);
 

rclcpp/include/rclcpp/context.hpp

@@ -23,8 +23,10 @@
 #include <typeindex>
 #include <typeinfo>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
+#include <stdexcept>
 
 #include "rcl/context.h"
 #include "rcl/guard_condition.h"
@@ -44,6 +46,23 @@ public:
   : std::runtime_error("context is already initialized") {}
 };
 
+/// Forward declare WeakContextsWrapper
+class WeakContextsWrapper;
+
+class ShutdownCallbackHandle
+{
+  friend class Context;
+
+public:
+  using ShutdownCallbackType = std::function<void ()>;
+
+private:
+  std::weak_ptr<ShutdownCallbackType> callback;
+};
+
+using OnShutdownCallbackHandle = ShutdownCallbackHandle;
+using PreShutdownCallbackHandle = ShutdownCallbackHandle;
+
 /// Context which encapsulates shared state between nodes and other similar entities.
 /**
  * A context also represents the lifecycle between init and shutdown of rclcpp.
@@ -60,7 +79,7 @@ public:
    * Every context which is constructed is added to a global vector of contexts,
    * which is used by the signal handler to conditionally shutdown each context
    * on SIGINT.
-   * See the shutdown_on_sigint option in the InitOptions class.
+   * See the shutdown_on_signal option in the InitOptions class.
    */
   RCLCPP_PUBLIC
   Context();
@@ -77,8 +96,8 @@ public:
    *
    * Note that this function does not setup any signal handlers, so if you want
    * it to be shutdown by the signal handler, then you need to either install
-   * them manually with rclcpp::install_signal_handers() or use rclcpp::init().
-   * In addition to installing the signal handlers, the shutdown_on_sigint
+   * them manually with rclcpp::install_signal_handlers() or use rclcpp::init().
+   * In addition to installing the signal handlers, the shutdown_on_signal
    * of the InitOptions needs to be `true` for this context to be shutdown by
    * the signal handler, otherwise it will be passed over.
    *
@@ -100,13 +119,16 @@ public:
    * \param[in] argv argument array which may contain arguments intended for ROS
    * \param[in] init_options initialization options for rclcpp and underlying layers
    * \throw ContextAlreadyInitialized if called if init is called more than once
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
+   * \throws std::runtime_error if the global logging configure mutex is NULL
+   * \throws exceptions::UnknownROSArgsError if there are unknown ROS arguments
    */
   RCLCPP_PUBLIC
   virtual
   void
   init(
     int argc,
-    char const * const argv[],
+    char const * const * argv,
     const rclcpp::InitOptions & init_options = rclcpp::InitOptions());
 
   /// Return true if the context is valid, otherwise false.
@@ -133,13 +155,18 @@ public:
   rclcpp::InitOptions
   get_init_options();
 
+  /// Return actual domain id.
+  RCLCPP_PUBLIC
+  size_t
+  get_domain_id() const;
+
   /// Return the shutdown reason, or empty string if not shutdown.
   /**
    * This function is thread-safe.
    */
   RCLCPP_PUBLIC
   std::string
-  shutdown_reason();
+  shutdown_reason() const;
 
   /// Shutdown the context, making it uninitialized and therefore invalid for derived entities.
   /**
@@ -166,7 +193,7 @@ public:
   bool
   shutdown(const std::string & reason);
 
-  using OnShutdownCallback = std::function<void ()>;
+  using OnShutdownCallback = OnShutdownCallbackHandle::ShutdownCallbackType;
 
   /// Add a on_shutdown callback to be called when shutdown is called for this context.
   /**
@@ -174,7 +201,7 @@ public:
    * to last step in shutdown().
    *
    * When shutdown occurs due to the signal handler, these callbacks are run
-   * asynchronoulsy in the dedicated singal handling thread.
+   * asynchronously in the dedicated singal handling thread.
    *
    * Also, shutdown() may be called from the destructor of this function.
    * Therefore, it is not safe to throw exceptions from these callbacks.
@@ -192,23 +219,82 @@ public:
   OnShutdownCallback
   on_shutdown(OnShutdownCallback callback);
 
-  /// Return the shutdown callbacks as const.
+  /// Add a on_shutdown callback to be called when shutdown is called for this context.
   /**
-   * Using the returned reference is not thread-safe with calls that modify
-   * the list of "on shutdown" callbacks, i.e. on_shutdown().
+   * These callbacks will be called in the order they are added as the second
+   * to last step in shutdown().
+   *
+   * When shutdown occurs due to the signal handler, these callbacks are run
+   * asynchronously in the dedicated signal handling thread.
+   *
+   * Also, shutdown() may be called from the destructor of this function.
+   * Therefore, it is not safe to throw exceptions from these callbacks.
+   * Instead, log errors or use some other mechanism to indicate an error has
+   * occurred.
+   *
+   * On shutdown callbacks may be registered before init and after shutdown,
+   * and persist on repeated init's.
+   *
+   * \param[in] callback the on_shutdown callback to be registered
+   * \return the created callback handle
    */
   RCLCPP_PUBLIC
-  const std::vector<OnShutdownCallback> &
-  get_on_shutdown_callbacks() const;
+  virtual
+  OnShutdownCallbackHandle
+  add_on_shutdown_callback(OnShutdownCallback callback);
+
+  /// Remove an registered on_shutdown callbacks.
+  /**
+   * \param[in] callback_handle the on_shutdown callback handle to be removed.
+   * \return true if the callback is found and removed, otherwise false.
+   */
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  remove_on_shutdown_callback(const OnShutdownCallbackHandle & callback_handle);
+
+  using PreShutdownCallback = PreShutdownCallbackHandle::ShutdownCallbackType;
+
+  /// Add a pre_shutdown callback to be called before shutdown is called for this context.
+  /**
+   * These callbacks will be called in the order they are added.
+   *
+   * When shutdown occurs due to the signal handler, these callbacks are run
+   * asynchronously in the dedicated signal handling thread.
+   *
+   * \param[in] callback the pre_shutdown callback to be registered
+   * \return the created callback handle
+   */
+  RCLCPP_PUBLIC
+  virtual
+  PreShutdownCallbackHandle
+  add_pre_shutdown_callback(PreShutdownCallback callback);
+
+  /// Remove an registered pre_shutdown callback.
+  /**
+   * \param[in] callback_handle the pre_shutdown callback handle to be removed.
+   * \return true if the callback is found and removed, otherwise false.
+   */
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  remove_pre_shutdown_callback(const PreShutdownCallbackHandle & callback_handle);
 
   /// Return the shutdown callbacks.
   /**
-   * Using the returned reference is not thread-safe with calls that modify
-   * the list of "on shutdown" callbacks, i.e. on_shutdown().
+   * Returned callbacks are a copy of the registered callbacks.
    */
   RCLCPP_PUBLIC
-  std::vector<OnShutdownCallback> &
-  get_on_shutdown_callbacks();
+  std::vector<OnShutdownCallback>
+  get_on_shutdown_callbacks() const;
+
+  /// Return the pre-shutdown callbacks.
+  /**
+   * Returned callbacks are a copy of the registered callbacks.
+   */
+  RCLCPP_PUBLIC
+  std::vector<PreShutdownCallback>
+  get_pre_shutdown_callbacks() const;
 
   /// Return the internal rcl context.
   RCLCPP_PUBLIC
@@ -221,7 +307,7 @@ public:
    *
    *   - this context is shutdown()
    *   - this context is destructed (resulting in shutdown)
-   *   - this context has shutdown_on_sigint=true and SIGINT occurs (resulting in shutdown)
+   *   - this context has shutdown_on_signal=true and SIGINT/SIGTERM occurs (resulting in shutdown)
    *   - interrupt_all_sleep_for() is called
    *
    * \param[in] nanoseconds A std::chrono::duration representing how long to sleep for.
@@ -237,64 +323,6 @@ public:
   void
   interrupt_all_sleep_for();
 
-  /// Get a handle to the guard condition which is triggered when interrupted.
-  /**
-   * This guard condition is triggered any time interrupt_all_wait_sets() is
-   * called, which may be called by the user, or shutdown().
-   * And in turn, shutdown() may be called by the user, the destructor of this
-   * context, or the signal handler if installed and shutdown_on_sigint is true
-   * for this context.
-   *
-   * The first time that this function is called for a given wait set a new guard
-   * condition will be created and returned; thereafter the same guard condition
-   * will be returned for the same wait set.
-   * This mechanism is designed to ensure that the same guard condition is not
-   * reused across wait sets (e.g., when using multiple executors in the same
-   * process).
-   * This method will throw an exception if initialization of the guard
-   * condition fails.
-   *
-   * The returned guard condition needs to be released with the
-   * release_interrupt_guard_condition() method in order to reclaim resources.
-   *
-   * \param[in] wait_set Pointer to the rcl_wait_set_t that will be using the
-   *   resulting guard condition.
-   * \return Pointer to the guard condition.
-   */
-  RCLCPP_PUBLIC
-  rcl_guard_condition_t *
-  get_interrupt_guard_condition(rcl_wait_set_t * wait_set);
-
-  /// Release the previously allocated guard condition which is triggered when interrupted.
-  /**
-   * If you previously called get_interrupt_guard_condition() for a given wait
-   * set to get a interrupt guard condition, then you should call
-   * release_interrupt_guard_condition() when you're done, to free that
-   * condition.
-   * Will throw an exception if get_interrupt_guard_condition() wasn't
-   * previously called for the given wait set.
-   *
-   * After calling this, the pointer returned by get_interrupt_guard_condition()
-   * for the given wait_set is invalid.
-   *
-   * \param[in] wait_set Pointer to the rcl_wait_set_t that was using the
-   *   resulting guard condition.
-   */
-  RCLCPP_PUBLIC
-  void
-  release_interrupt_guard_condition(rcl_wait_set_t * wait_set);
-
-  /// Nothrow version of release_interrupt_guard_condition(), logs to RCLCPP_ERROR instead.
-  RCLCPP_PUBLIC
-  void
-  release_interrupt_guard_condition(rcl_wait_set_t * wait_set, const std::nothrow_t &) noexcept;
-
-  /// Interrupt any blocking executors, or wait sets associated with this context.
-  RCLCPP_PUBLIC
-  virtual
-  void
-  interrupt_all_wait_sets();
-
   /// Return a singleton instance for the SubContext type, constructing one if necessary.
   template<typename SubContext, typename ... Args>
   std::shared_ptr<SubContext>
@@ -333,28 +361,55 @@ private:
 
   // This mutex is recursive so that the destructor can ensure atomicity
   // between is_initialized and shutdown.
-  std::recursive_mutex init_mutex_;
+  mutable std::recursive_mutex init_mutex_;
   std::shared_ptr<rcl_context_t> rcl_context_;
   rclcpp::InitOptions init_options_;
   std::string shutdown_reason_;
 
+  // Keep shared ownership of the global logging mutex.
+  std::shared_ptr<std::recursive_mutex> logging_mutex_;
+
   std::unordered_map<std::type_index, std::shared_ptr<void>> sub_contexts_;
   // This mutex is recursive so that the constructor of a sub context may
   // attempt to acquire another sub context.
   std::recursive_mutex sub_contexts_mutex_;
 
-  std::vector<OnShutdownCallback> on_shutdown_callbacks_;
-  std::mutex on_shutdown_callbacks_mutex_;
+  std::unordered_set<std::shared_ptr<OnShutdownCallback>> on_shutdown_callbacks_;
+  mutable std::mutex on_shutdown_callbacks_mutex_;
+
+  std::unordered_set<std::shared_ptr<PreShutdownCallback>> pre_shutdown_callbacks_;
+  mutable std::mutex pre_shutdown_callbacks_mutex_;
 
   /// Condition variable for timed sleep (see sleep_for).
   std::condition_variable interrupt_condition_variable_;
   /// Mutex for protecting the global condition variable.
   std::mutex interrupt_mutex_;
 
-  /// Mutex to protect sigint_guard_cond_handles_.
-  std::mutex interrupt_guard_cond_handles_mutex_;
-  /// Guard conditions for interrupting of associated wait sets on interrupt_all_wait_sets().
-  std::unordered_map<rcl_wait_set_t *, rcl_guard_condition_t> interrupt_guard_cond_handles_;
+  /// Keep shared ownership of global vector of weak contexts
+  std::shared_ptr<WeakContextsWrapper> weak_contexts_;
+
+  enum class ShutdownType
+  {
+    pre_shutdown,
+    on_shutdown
+  };
+
+  using ShutdownCallback = ShutdownCallbackHandle::ShutdownCallbackType;
+
+  RCLCPP_LOCAL
+  ShutdownCallbackHandle
+  add_shutdown_callback(
+    ShutdownType shutdown_type,
+    ShutdownCallback callback);
+
+  RCLCPP_LOCAL
+  bool
+  remove_shutdown_callback(
+    ShutdownType shutdown_type,
+    const ShutdownCallbackHandle & callback_handle);
+
+  std::vector<rclcpp::Context::ShutdownCallback>
+  get_shutdown_callback(ShutdownType shutdown_type) const;
 };
 
 /// Return a copy of the list of context shared pointers.

rclcpp/include/rclcpp/contexts/default_context.hpp

@@ -36,22 +36,6 @@ RCLCPP_PUBLIC
 DefaultContext::SharedPtr
 get_global_default_context();
 
-namespace default_context
-{
-
-using DefaultContext
-[[deprecated("use rclcpp::contexts::DefaultContext instead")]] = DefaultContext;
-
-[[deprecated("use rclcpp::contexts::get_global_default_context() instead")]]
-RCLCPP_PUBLIC
-inline
-DefaultContext::SharedPtr
-get_global_default_context()
-{
-  return rclcpp::contexts::get_global_default_context();
-}
-
-}  // namespace default_context
 }  // namespace contexts
 }  // namespace rclcpp
 

rclcpp/include/rclcpp/create_generic_publisher.hpp

@@ -0,0 +1,69 @@
+// Copyright 2020, Apex.AI Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__CREATE_GENERIC_PUBLISHER_HPP_
+#define RCLCPP__CREATE_GENERIC_PUBLISHER_HPP_
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "rclcpp/generic_publisher.hpp"
+#include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/publisher_options.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/typesupport_helpers.hpp"
+
+namespace rclcpp
+{
+
+/// Create and return a GenericPublisher.
+/**
+ * The returned pointer will never be empty, but this function can throw various exceptions, for
+ * instance when the message's package can not be found on the AMENT_PREFIX_PATH.
+ *
+ * \param topics_interface NodeTopicsInterface pointer used in parts of the setup
+ * \param topic_name Topic name
+ * \param topic_type Topic type
+ * \param qos %QoS settings
+ * \param options %Publisher options.
+ * Not all publisher options are currently respected, the only relevant options for this
+ * publisher are `event_callbacks`, `use_default_callbacks`, and `%callback_group`.
+ */
+template<typename AllocatorT = std::allocator<void>>
+std::shared_ptr<GenericPublisher> create_generic_publisher(
+  rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr topics_interface,
+  const std::string & topic_name,
+  const std::string & topic_type,
+  const rclcpp::QoS & qos,
+  const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::PublisherOptionsWithAllocator<AllocatorT>()
+  )
+)
+{
+  auto ts_lib = rclcpp::get_typesupport_library(topic_type, "rosidl_typesupport_cpp");
+  auto pub = std::make_shared<GenericPublisher>(
+    topics_interface->get_node_base_interface(),
+    std::move(ts_lib),
+    topic_name,
+    topic_type,
+    qos,
+    options);
+  topics_interface->add_publisher(pub, options.callback_group);
+  return pub;
+}
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__CREATE_GENERIC_PUBLISHER_HPP_

rclcpp/include/rclcpp/create_generic_subscription.hpp

@@ -0,0 +1,79 @@
+// Copyright 2020, Apex.AI Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__CREATE_GENERIC_SUBSCRIPTION_HPP_
+#define RCLCPP__CREATE_GENERIC_SUBSCRIPTION_HPP_
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "rcl/subscription.h"
+#include "rclcpp/generic_subscription.hpp"
+#include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/serialized_message.hpp"
+#include "rclcpp/subscription_options.hpp"
+#include "rclcpp/typesupport_helpers.hpp"
+
+namespace rclcpp
+{
+
+/// Create and return a GenericSubscription.
+/**
+ * The returned pointer will never be empty, but this function can throw various exceptions, for
+ * instance when the message's package can not be found on the AMENT_PREFIX_PATH.
+ *
+ * \param topics_interface NodeTopicsInterface pointer used in parts of the setup.
+ * \param topic_name Topic name
+ * \param topic_type Topic type
+ * \param qos %QoS settings
+ * \param callback Callback for new messages of serialized form
+ * \param options %Publisher options.
+ * Not all publisher options are currently respected, the only relevant options for this
+ * publisher are `event_callbacks`, `use_default_callbacks`, and `%callback_group`.
+ */
+template<typename AllocatorT = std::allocator<void>>
+std::shared_ptr<GenericSubscription> create_generic_subscription(
+  rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr topics_interface,
+  const std::string & topic_name,
+  const std::string & topic_type,
+  const rclcpp::QoS & qos,
+  std::function<void(std::shared_ptr<rclcpp::SerializedMessage>)> callback,
+  const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::SubscriptionOptionsWithAllocator<AllocatorT>()
+  )
+)
+{
+  auto ts_lib = rclcpp::get_typesupport_library(
+    topic_type, "rosidl_typesupport_cpp");
+
+  auto subscription = std::make_shared<GenericSubscription>(
+    topics_interface->get_node_base_interface(),
+    std::move(ts_lib),
+    topic_name,
+    topic_type,
+    qos,
+    callback,
+    options);
+
+  topics_interface->add_subscription(subscription, options.callback_group);
+
+  return subscription;
+}
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__CREATE_GENERIC_SUBSCRIPTION_HPP_

rclcpp/include/rclcpp/create_publisher.hpp

@@ -17,6 +17,7 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 
 #include "rclcpp/node_interfaces/get_node_topics_interface.hpp"
 #include "rclcpp/node_interfaces/node_topics_interface.hpp"
@@ -24,15 +25,65 @@
 #include "rclcpp/publisher_factory.hpp"
 #include "rclcpp/publisher_options.hpp"
 #include "rclcpp/qos.hpp"
+#include "rclcpp/qos_overriding_options.hpp"
+#include "rclcpp/detail/qos_parameters.hpp"
+
 #include "rmw/qos_profiles.h"
 
 namespace rclcpp
 {
 
+namespace detail
+{
+/// Create and return a publisher of the given MessageT type.
+template<
+  typename MessageT,
+  typename AllocatorT = std::allocator<void>,
+  typename PublisherT = rclcpp::Publisher<MessageT, AllocatorT>,
+  typename NodeParametersT,
+  typename NodeTopicsT>
+std::shared_ptr<PublisherT>
+create_publisher(
+  NodeParametersT & node_parameters,
+  NodeTopicsT & node_topics,
+  const std::string & topic_name,
+  const rclcpp::QoS & qos,
+  const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::PublisherOptionsWithAllocator<AllocatorT>()
+  )
+)
+{
+  auto node_topics_interface = rclcpp::node_interfaces::get_node_topics_interface(node_topics);
+  const rclcpp::QoS & actual_qos = options.qos_overriding_options.get_policy_kinds().size() ?
+    rclcpp::detail::declare_qos_parameters(
+    options.qos_overriding_options, node_parameters,
+    node_topics_interface->resolve_topic_name(topic_name),
+    qos, rclcpp::detail::PublisherQosParametersTraits{}) :
+    qos;
+
+  // Create the publisher.
+  auto pub = node_topics_interface->create_publisher(
+    topic_name,
+    rclcpp::create_publisher_factory<MessageT, AllocatorT, PublisherT>(options),
+    actual_qos
+  );
+
+  // Add the publisher to the node topics interface.
+  node_topics_interface->add_publisher(pub, options.callback_group);
+
+  return std::dynamic_pointer_cast<PublisherT>(pub);
+}
+}  // namespace detail
+
+
 /// Create and return a publisher of the given MessageT type.
 /**
  * The NodeT type only needs to have a method called get_node_topics_interface()
  * which returns a shared_ptr to a NodeTopicsInterface.
+ *
+ * In case `options.qos_overriding_options` is enabling qos parameter overrides,
+ * NodeT must also have a method called get_node_parameters_interface()
+ * which returns a shared_ptr to a NodeParametersInterface.
  */
 template<
   typename MessageT,
@@ -41,7 +92,7 @@ template<
   typename NodeT>
 std::shared_ptr<PublisherT>
 create_publisher(
-  NodeT & node,
+  NodeT && node,
   const std::string & topic_name,
   const rclcpp::QoS & qos,
   const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options = (
@@ -49,21 +100,28 @@ create_publisher(
   )
 )
 {
-  // Extract the NodeTopicsInterface from the NodeT.
-  using rclcpp::node_interfaces::get_node_topics_interface;
-  auto node_topics = get_node_topics_interface(node);
+  return detail::create_publisher<MessageT, AllocatorT, PublisherT>(
+    node, node, topic_name, qos, options);
+}
 
-  // Create the publisher.
-  auto pub = node_topics->create_publisher(
-    topic_name,
-    rclcpp::create_publisher_factory<MessageT, AllocatorT, PublisherT>(options),
-    qos
-  );
-
-  // Add the publisher to the node topics interface.
-  node_topics->add_publisher(pub, options.callback_group);
-
-  return std::dynamic_pointer_cast<PublisherT>(pub);
+/// Create and return a publisher of the given MessageT type.
+template<
+  typename MessageT,
+  typename AllocatorT = std::allocator<void>,
+  typename PublisherT = rclcpp::Publisher<MessageT, AllocatorT>>
+std::shared_ptr<PublisherT>
+create_publisher(
+  rclcpp::node_interfaces::NodeParametersInterface::SharedPtr & node_parameters,
+  rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr & node_topics,
+  const std::string & topic_name,
+  const rclcpp::QoS & qos,
+  const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::PublisherOptionsWithAllocator<AllocatorT>()
+  )
+)
+{
+  return detail::create_publisher<MessageT, AllocatorT, PublisherT>(
+    node_parameters, node_topics, topic_name, qos, options);
 }
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/create_subscription.hpp

@@ -15,41 +15,47 @@
 #ifndef RCLCPP__CREATE_SUBSCRIPTION_HPP_
 #define RCLCPP__CREATE_SUBSCRIPTION_HPP_
 
+#include <chrono>
+#include <functional>
 #include <memory>
+#include <stdexcept>
 #include <string>
 #include <utility>
 
+#include "rclcpp/detail/resolve_enable_topic_statistics.hpp"
+
+#include "rclcpp/node_interfaces/get_node_timers_interface.hpp"
 #include "rclcpp/node_interfaces/get_node_topics_interface.hpp"
+#include "rclcpp/node_interfaces/node_timers_interface.hpp"
 #include "rclcpp/node_interfaces/node_topics_interface.hpp"
+
+#include "rclcpp/create_publisher.hpp"
+#include "rclcpp/create_timer.hpp"
+#include "rclcpp/qos.hpp"
 #include "rclcpp/subscription_factory.hpp"
 #include "rclcpp/subscription_options.hpp"
-#include "rclcpp/qos.hpp"
+#include "rclcpp/timer.hpp"
+#include "rclcpp/topic_statistics/subscription_topic_statistics.hpp"
 #include "rmw/qos_profiles.h"
 
 namespace rclcpp
 {
 
-/// Create and return a subscription of the given MessageT type.
-/**
- * The NodeT type only needs to have a method called get_node_topics_interface()
- * which returns a shared_ptr to a NodeTopicsInterface, or be a
- * NodeTopicsInterface pointer itself.
- */
+namespace detail
+{
 template<
   typename MessageT,
   typename CallbackT,
-  typename AllocatorT = std::allocator<void>,
-  typename CallbackMessageT =
-  typename rclcpp::subscription_traits::has_message_type<CallbackT>::type,
-  typename SubscriptionT = rclcpp::Subscription<CallbackMessageT, AllocatorT>,
-  typename MessageMemoryStrategyT = rclcpp::message_memory_strategy::MessageMemoryStrategy<
-    CallbackMessageT,
-    AllocatorT
-  >,
-  typename NodeT>
+  typename AllocatorT,
+  typename SubscriptionT,
+  typename MessageMemoryStrategyT,
+  typename NodeParametersT,
+  typename NodeTopicsT,
+  typename ROSMessageType = typename SubscriptionT::ROSMessageType>
 typename std::shared_ptr<SubscriptionT>
 create_subscription(
-  NodeT && node,
+  NodeParametersT & node_parameters,
+  NodeTopicsT & node_topics,
   const std::string & topic_name,
   const rclcpp::QoS & qos,
   CallbackT && callback,
@@ -62,19 +68,160 @@ create_subscription(
 )
 {
   using rclcpp::node_interfaces::get_node_topics_interface;
-  auto node_topics = get_node_topics_interface(std::forward<NodeT>(node));
+  auto node_topics_interface = get_node_topics_interface(node_topics);
+
+  std::shared_ptr<rclcpp::topic_statistics::SubscriptionTopicStatistics<ROSMessageType>>
+  subscription_topic_stats = nullptr;
+
+  if (rclcpp::detail::resolve_enable_topic_statistics(
+      options,
+      *node_topics_interface->get_node_base_interface()))
+  {
+    if (options.topic_stats_options.publish_period <= std::chrono::milliseconds(0)) {
+      throw std::invalid_argument(
+              "topic_stats_options.publish_period must be greater than 0, specified value of " +
+              std::to_string(options.topic_stats_options.publish_period.count()) +
+              " ms");
+    }
+
+    std::shared_ptr<Publisher<statistics_msgs::msg::MetricsMessage>>
+    publisher = rclcpp::detail::create_publisher<statistics_msgs::msg::MetricsMessage>(
+      node_parameters,
+      node_topics_interface,
+      options.topic_stats_options.publish_topic,
+      qos);
+
+    subscription_topic_stats = std::make_shared<
+      rclcpp::topic_statistics::SubscriptionTopicStatistics<ROSMessageType>
+      >(node_topics_interface->get_node_base_interface()->get_name(), publisher);
+
+    std::weak_ptr<
+      rclcpp::topic_statistics::SubscriptionTopicStatistics<ROSMessageType>
+    > weak_subscription_topic_stats(subscription_topic_stats);
+    auto sub_call_back = [weak_subscription_topic_stats]() {
+        auto subscription_topic_stats = weak_subscription_topic_stats.lock();
+        if (subscription_topic_stats) {
+          subscription_topic_stats->publish_message_and_reset_measurements();
+        }
+      };
+
+    auto node_timer_interface = node_topics_interface->get_node_timers_interface();
+
+    auto timer = create_wall_timer(
+      std::chrono::duration_cast<std::chrono::nanoseconds>(
+        options.topic_stats_options.publish_period),
+      sub_call_back,
+      options.callback_group,
+      node_topics_interface->get_node_base_interface(),
+      node_timer_interface
+    );
+
+    subscription_topic_stats->set_publisher_timer(timer);
+  }
 
   auto factory = rclcpp::create_subscription_factory<MessageT>(
     std::forward<CallbackT>(callback),
     options,
-    msg_mem_strat
+    msg_mem_strat,
+    subscription_topic_stats
   );
 
-  auto sub = node_topics->create_subscription(topic_name, factory, qos);
-  node_topics->add_subscription(sub, options.callback_group);
+  const rclcpp::QoS & actual_qos = options.qos_overriding_options.get_policy_kinds().size() ?
+    rclcpp::detail::declare_qos_parameters(
+    options.qos_overriding_options, node_parameters,
+    node_topics_interface->resolve_topic_name(topic_name),
+    qos, rclcpp::detail::SubscriptionQosParametersTraits{}) :
+    qos;
+
+  auto sub = node_topics_interface->create_subscription(topic_name, factory, actual_qos);
+  node_topics_interface->add_subscription(sub, options.callback_group);
 
   return std::dynamic_pointer_cast<SubscriptionT>(sub);
 }
+}  // namespace detail
+
+/// Create and return a subscription of the given MessageT type.
+/**
+ * The NodeT type only needs to have a method called get_node_topics_interface()
+ * which returns a shared_ptr to a NodeTopicsInterface, or be a
+ * NodeTopicsInterface pointer itself.
+ *
+ * In case `options.qos_overriding_options` is enabling qos parameter overrides,
+ * NodeT must also have a method called get_node_parameters_interface()
+ * which returns a shared_ptr to a NodeParametersInterface.
+ *
+ * \tparam MessageT
+ * \tparam CallbackT
+ * \tparam AllocatorT
+ * \tparam SubscriptionT
+ * \tparam MessageMemoryStrategyT
+ * \tparam NodeT
+ * \param node
+ * \param topic_name
+ * \param qos
+ * \param callback
+ * \param options
+ * \param msg_mem_strat
+ * \return the created subscription
+ * \throws std::invalid_argument if topic statistics is enabled and the publish period is
+ * less than or equal to zero.
+ */
+template<
+  typename MessageT,
+  typename CallbackT,
+  typename AllocatorT = std::allocator<void>,
+  typename SubscriptionT = rclcpp::Subscription<MessageT, AllocatorT>,
+  typename MessageMemoryStrategyT = typename SubscriptionT::MessageMemoryStrategyType,
+  typename NodeT>
+typename std::shared_ptr<SubscriptionT>
+create_subscription(
+  NodeT & node,
+  const std::string & topic_name,
+  const rclcpp::QoS & qos,
+  CallbackT && callback,
+  const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::SubscriptionOptionsWithAllocator<AllocatorT>()
+  ),
+  typename MessageMemoryStrategyT::SharedPtr msg_mem_strat = (
+    MessageMemoryStrategyT::create_default()
+  )
+)
+{
+  return rclcpp::detail::create_subscription<
+    MessageT, CallbackT, AllocatorT, SubscriptionT, MessageMemoryStrategyT>(
+    node, node, topic_name, qos, std::forward<CallbackT>(callback), options, msg_mem_strat);
+}
+
+/// Create and return a subscription of the given MessageT type.
+/**
+ * See \ref create_subscription().
+ */
+template<
+  typename MessageT,
+  typename CallbackT,
+  typename AllocatorT = std::allocator<void>,
+  typename SubscriptionT = rclcpp::Subscription<MessageT, AllocatorT>,
+  typename MessageMemoryStrategyT = typename SubscriptionT::MessageMemoryStrategyType>
+typename std::shared_ptr<SubscriptionT>
+create_subscription(
+  rclcpp::node_interfaces::NodeParametersInterface::SharedPtr & node_parameters,
+  rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr & node_topics,
+  const std::string & topic_name,
+  const rclcpp::QoS & qos,
+  CallbackT && callback,
+  const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options = (
+    rclcpp::SubscriptionOptionsWithAllocator<AllocatorT>()
+  ),
+  typename MessageMemoryStrategyT::SharedPtr msg_mem_strat = (
+    MessageMemoryStrategyT::create_default()
+  )
+)
+{
+  return rclcpp::detail::create_subscription<
+    MessageT, CallbackT, AllocatorT, SubscriptionT, MessageMemoryStrategyT>(
+    node_parameters, node_topics, topic_name, qos,
+    std::forward<CallbackT>(callback), options, msg_mem_strat);
+}
 
 }  // namespace rclcpp
 

rclcpp/include/rclcpp/create_timer.hpp

@@ -15,6 +15,8 @@
 #ifndef RCLCPP__CREATE_TIMER_HPP_
 #define RCLCPP__CREATE_TIMER_HPP_
 
+#include <chrono>
+#include <exception>
 #include <memory>
 #include <string>
 #include <utility>
@@ -32,8 +34,8 @@ namespace rclcpp
 template<typename CallbackT>
 typename rclcpp::TimerBase::SharedPtr
 create_timer(
-  node_interfaces::NodeBaseInterface * node_base,
-  node_interfaces::NodeTimersInterface * node_timers,
+  std::shared_ptr<node_interfaces::NodeBaseInterface> node_base,
+  std::shared_ptr<node_interfaces::NodeTimersInterface> node_timers,
   rclcpp::Clock::SharedPtr clock,
   rclcpp::Duration period,
   CallbackT && callback,
@@ -68,6 +70,74 @@ create_timer(
     group);
 }
 
+/// Convenience method to create a timer with node resources.
+/**
+ *
+ * \tparam DurationRepT
+ * \tparam DurationT
+ * \tparam CallbackT
+ * \param period period to execute callback. This duration must be 0 <= period < nanoseconds::max()
+ * \param callback callback to execute via the timer period
+ * \param group
+ * \param node_base
+ * \param node_timers
+ * \return
+ * \throws std::invalid argument if either node_base or node_timers
+ * are null, or period is negative or too large
+ */
+template<typename DurationRepT, typename DurationT, typename CallbackT>
+typename rclcpp::WallTimer<CallbackT>::SharedPtr
+create_wall_timer(
+  std::chrono::duration<DurationRepT, DurationT> period,
+  CallbackT callback,
+  rclcpp::CallbackGroup::SharedPtr group,
+  node_interfaces::NodeBaseInterface * node_base,
+  node_interfaces::NodeTimersInterface * node_timers)
+{
+  if (node_base == nullptr) {
+    throw std::invalid_argument{"input node_base cannot be null"};
+  }
+
+  if (node_timers == nullptr) {
+    throw std::invalid_argument{"input node_timers cannot be null"};
+  }
+
+  if (period < std::chrono::duration<DurationRepT, DurationT>::zero()) {
+    throw std::invalid_argument{"timer period cannot be negative"};
+  }
+
+  // Casting to a double representation might lose precision and allow the check below to succeed
+  // but the actual cast to nanoseconds fail. Using 1 DurationT worth of nanoseconds less than max.
+  constexpr auto maximum_safe_cast_ns =
+    std::chrono::nanoseconds::max() - std::chrono::duration<DurationRepT, DurationT>(1);
+
+  // If period is greater than nanoseconds::max(), the duration_cast to nanoseconds will overflow
+  // a signed integer, which is undefined behavior. Checking whether any std::chrono::duration is
+  // greater than nanoseconds::max() is a difficult general problem. This is a more conservative
+  // version of Howard Hinnant's (the <chrono> guy>) response here:
+  // https://stackoverflow.com/a/44637334/2089061
+  // However, this doesn't solve the issue for all possible duration types of period.
+  // Follow-up issue: https://github.com/ros2/rclcpp/issues/1177
+  constexpr auto ns_max_as_double =
+    std::chrono::duration_cast<std::chrono::duration<double, std::chrono::nanoseconds::period>>(
+    maximum_safe_cast_ns);
+  if (period > ns_max_as_double) {
+    throw std::invalid_argument{
+            "timer period must be less than std::chrono::nanoseconds::max()"};
+  }
+
+  const auto period_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(period);
+  if (period_ns < std::chrono::nanoseconds::zero()) {
+    throw std::runtime_error{
+            "Casting timer period to nanoseconds resulted in integer overflow."};
+  }
+
+  auto timer = rclcpp::WallTimer<CallbackT>::make_shared(
+    period_ns, std::move(callback), node_base->get_context());
+  node_timers->add_timer(timer, group);
+  return timer;
+}
+
 }  // namespace rclcpp
 
 #endif  // RCLCPP__CREATE_TIMER_HPP_

rclcpp/include/rclcpp/detail/add_guard_condition_to_rcl_wait_set.hpp

@@ -0,0 +1,39 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__DETAIL__ADD_GUARD_CONDITION_TO_RCL_WAIT_SET_HPP_
+#define RCLCPP__DETAIL__ADD_GUARD_CONDITION_TO_RCL_WAIT_SET_HPP_
+
+#include "rclcpp/guard_condition.hpp"
+
+namespace rclcpp
+{
+namespace detail
+{
+
+/// Adds the guard condition to a waitset
+/**
+ * \param[in] wait_set reference to a wait set where to add the guard condition
+ * \param[in] guard_condition reference to the guard_condition to be added
+ */
+RCLCPP_PUBLIC
+void
+add_guard_condition_to_rcl_wait_set(
+  rcl_wait_set_t & wait_set,
+  const rclcpp::GuardCondition & guard_condition);
+
+}  // namespace detail
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__ADD_GUARD_CONDITION_TO_RCL_WAIT_SET_HPP_

rclcpp/include/rclcpp/detail/cpp_callback_trampoline.hpp

@@ -0,0 +1,68 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__DETAIL__CPP_CALLBACK_TRAMPOLINE_HPP_
+#define RCLCPP__DETAIL__CPP_CALLBACK_TRAMPOLINE_HPP_
+
+#include <functional>
+
+namespace rclcpp
+{
+
+namespace detail
+{
+
+/// Trampoline pattern for wrapping std::function into C-style callbacks.
+/**
+ * A common pattern in C is for a function to take a function pointer and a
+ * void pointer for "user data" which is passed to the function pointer when it
+ * is called from within C.
+ *
+ * It works by using the user data pointer to store a pointer to a
+ * std::function instance.
+ * So when called from C, this function will cast the user data to the right
+ * std::function type and call it.
+ *
+ * This should allow you to use free functions, lambdas with and without
+ * captures, and various kinds of std::bind instances.
+ *
+ * The interior of this function is likely to be executed within a C runtime,
+ * so no exceptions should be thrown at this point, and doing so results in
+ * undefined behavior.
+ *
+ * \tparam UserDataT Deduced type based on what is passed for user data,
+ *   usually this type is either `void *` or `const void *`.
+ * \tparam Args the arguments being passed to the callback
+ * \tparam ReturnT the return type of this function and the callback, default void
+ * \param user_data the function pointer, possibly type erased
+ * \param args the arguments to be forwarded to the callback
+ * \returns whatever the callback returns, if anything
+ */
+template<
+  typename UserDataT,
+  typename ... Args,
+  typename ReturnT = void
+>
+ReturnT
+cpp_callback_trampoline(UserDataT user_data, Args ... args) noexcept
+{
+  auto & actual_callback = *reinterpret_cast<const std::function<ReturnT(Args...)> *>(user_data);
+  return actual_callback(args ...);
+}
+
+}  // namespace detail
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__CPP_CALLBACK_TRAMPOLINE_HPP_

rclcpp/include/rclcpp/detail/qos_parameters.hpp

@@ -0,0 +1,340 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__DETAIL__QOS_PARAMETERS_HPP_
+#define RCLCPP__DETAIL__QOS_PARAMETERS_HPP_
+
+#include <algorithm>
+#include <array>
+#include <functional>
+#include <initializer_list>
+#include <map>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#include "rcl_interfaces/msg/parameter_descriptor.hpp"
+#include "rcpputils/pointer_traits.hpp"
+#include "rmw/qos_string_conversions.h"
+
+#include "rclcpp/duration.hpp"
+#include "rclcpp/node_interfaces/get_node_parameters_interface.hpp"
+#include "rclcpp/node_interfaces/node_parameters_interface.hpp"
+#include "rclcpp/qos_overriding_options.hpp"
+
+namespace rclcpp
+{
+namespace detail
+{
+
+/// \internal Trait used to specialize `declare_qos_parameters()` for publishers.
+struct PublisherQosParametersTraits
+{
+  static constexpr const char * entity_type() {return "publisher";}
+  static constexpr auto allowed_policies()
+  {
+    return std::array<::rclcpp::QosPolicyKind, 9> {
+      QosPolicyKind::AvoidRosNamespaceConventions,
+      QosPolicyKind::Deadline,
+      QosPolicyKind::Durability,
+      QosPolicyKind::History,
+      QosPolicyKind::Depth,
+      QosPolicyKind::Lifespan,
+      QosPolicyKind::Liveliness,
+      QosPolicyKind::LivelinessLeaseDuration,
+      QosPolicyKind::Reliability,
+    };
+  }
+};
+
+/// \internal Trait used to specialize `declare_qos_parameters()` for subscriptions.
+struct SubscriptionQosParametersTraits
+{
+  static constexpr const char * entity_type() {return "subscription";}
+  static constexpr auto allowed_policies()
+  {
+    return std::array<::rclcpp::QosPolicyKind, 8> {
+      QosPolicyKind::AvoidRosNamespaceConventions,
+      QosPolicyKind::Deadline,
+      QosPolicyKind::Durability,
+      QosPolicyKind::History,
+      QosPolicyKind::Depth,
+      QosPolicyKind::Liveliness,
+      QosPolicyKind::LivelinessLeaseDuration,
+      QosPolicyKind::Reliability,
+    };
+  }
+};
+
+/// \internal Returns the given `policy` of the profile `qos` converted to a parameter value.
+inline
+::rclcpp::ParameterValue
+get_default_qos_param_value(rclcpp::QosPolicyKind policy, const rclcpp::QoS & qos);
+
+/// \internal Modify the given `policy` in `qos` to be `value`.
+inline
+void
+apply_qos_override(
+  rclcpp::QosPolicyKind policy, rclcpp::ParameterValue value, rclcpp::QoS & qos);
+
+inline
+rclcpp::ParameterValue
+declare_parameter_or_get(
+  rclcpp::node_interfaces::NodeParametersInterface & parameters_interface,
+  const std::string & param_name,
+  rclcpp::ParameterValue param_value,
+  rcl_interfaces::msg::ParameterDescriptor descriptor)
+{
+  try {
+    return parameters_interface.declare_parameter(
+      param_name, param_value, descriptor);
+  } catch (const rclcpp::exceptions::ParameterAlreadyDeclaredException &) {
+    return parameters_interface.get_parameter(param_name).get_parameter_value();
+  }
+}
+
+#ifdef DOXYGEN_ONLY
+/// \internal Declare QoS parameters for the given entity.
+/**
+ * \tparam NodeT Node pointer or reference type.
+ * \tparam EntityQosParametersTraits A class with two static methods: `entity_type()` and
+ *  `allowed_policies()`. See `PublisherQosParametersTraits` and `SubscriptionQosParametersTraits`.
+ * \param options User provided options that indicate if QoS parameter overrides should be
+ *  declared or not, which policy can have overrides, and optionally a callback to validate the profile.
+ * \param node Parameters will be declared using this node.
+ * \param topic_name Name of the topic of the entity.
+ * \param default_qos User provided qos. It will be used as a default for the parameters declared.
+ * \return qos profile based on the user provided parameter overrides.
+ */
+template<typename NodeT, typename EntityQosParametersTraits>
+rclcpp::QoS
+  declare_qos_parameters(
+  const ::rclcpp::QosOverridingOptions & options,
+  NodeT & node,
+  const std::string & topic_name,
+  const ::rclcpp::QoS & default_qos,
+  EntityQosParametersTraits);
+
+#else
+
+template<typename NodeT, typename EntityQosParametersTraits>
+std::enable_if_t<
+  (rclcpp::node_interfaces::has_node_parameters_interface<
+    decltype(std::declval<typename rcpputils::remove_pointer<NodeT>::type>())>::value ||
+  std::is_same<typename std::decay_t<NodeT>,
+  rclcpp::node_interfaces::NodeParametersInterface::SharedPtr>::value),
+  rclcpp::QoS>
+declare_qos_parameters(
+  const ::rclcpp::QosOverridingOptions & options,
+  NodeT & node,
+  const std::string & topic_name,
+  const ::rclcpp::QoS & default_qos,
+  EntityQosParametersTraits)
+{
+  auto & parameters_interface = *rclcpp::node_interfaces::get_node_parameters_interface(node);
+  std::string param_prefix;
+  const auto & id = options.get_id();
+  {
+    std::ostringstream oss{"qos_overrides.", std::ios::ate};
+    oss << topic_name << "." << EntityQosParametersTraits::entity_type();
+    if (!id.empty()) {
+      oss << "_" << id;
+    }
+    oss << ".";
+    param_prefix = oss.str();
+  }
+  std::string param_description_suffix;
+  {
+    std::ostringstream oss{"} for ", std::ios::ate};
+    oss << EntityQosParametersTraits::entity_type() << " {" << topic_name << "}";
+    if (!id.empty()) {
+      oss << " with id {" << id << "}";
+    }
+    param_description_suffix = oss.str();
+  }
+  rclcpp::QoS qos = default_qos;
+  for (auto policy : EntityQosParametersTraits::allowed_policies()) {
+    if (
+      std::count(options.get_policy_kinds().begin(), options.get_policy_kinds().end(), policy))
+    {
+      std::ostringstream param_name{param_prefix, std::ios::ate};
+      param_name << qos_policy_kind_to_cstr(policy);
+      std::ostringstream param_desciption{"qos policy {", std::ios::ate};
+      param_desciption << qos_policy_kind_to_cstr(policy) << param_description_suffix;
+      rcl_interfaces::msg::ParameterDescriptor descriptor{};
+      descriptor.description = param_desciption.str();
+      descriptor.read_only = true;
+      auto value = declare_parameter_or_get(
+        parameters_interface, param_name.str(),
+        get_default_qos_param_value(policy, qos), descriptor);
+      ::rclcpp::detail::apply_qos_override(policy, value, qos);
+    }
+  }
+  const auto & validation_callback = options.get_validation_callback();
+  if (validation_callback) {
+    auto result = validation_callback(qos);
+    if (!result.successful) {
+      throw rclcpp::exceptions::InvalidQosOverridesException{
+              "validation callback failed: " + result.reason};
+    }
+  }
+  return qos;
+}
+
+// TODO(ivanpauno): This overload cannot declare the QoS parameters, as a node parameters interface
+// was not provided.
+template<typename NodeT, typename EntityQosParametersTraits>
+std::enable_if_t<
+  !(rclcpp::node_interfaces::has_node_parameters_interface<
+    decltype(std::declval<typename rcpputils::remove_pointer<NodeT>::type>())>::value ||
+  std::is_same<typename std::decay_t<NodeT>,
+  rclcpp::node_interfaces::NodeParametersInterface::SharedPtr>::value),
+  rclcpp::QoS>
+declare_qos_parameters(
+  const ::rclcpp::QosOverridingOptions & options,
+  NodeT &,
+  const std::string &,
+  const ::rclcpp::QoS & default_qos,
+  EntityQosParametersTraits)
+{
+  if (options.get_policy_kinds().size()) {
+    std::runtime_error exc{
+      "passed non-default qos overriding options without providing a parameters interface"};
+    throw exc;
+  }
+  return default_qos;
+}
+
+#endif
+
+/// \internal Helper function to get a rmw qos policy value from a string.
+#define RCLCPP_DETAIL_APPLY_QOS_OVERRIDE_FROM_PARAMETER_STRING( \
+    kind_lower, kind_upper, parameter_value, rclcpp_qos) \
+  do { \
+    auto policy_string = (parameter_value).get<std::string>(); \
+    auto policy_value = rmw_qos_ ## kind_lower ## _policy_from_str(policy_string.c_str()); \
+    if (RMW_QOS_POLICY_ ## kind_upper ## _UNKNOWN == policy_value) { \
+      throw std::invalid_argument{"unknown QoS policy " #kind_lower " value: " + policy_string}; \
+    } \
+    ((rclcpp_qos).kind_lower)(policy_value); \
+  } while (0)
+
+inline
+void
+apply_qos_override(
+  rclcpp::QosPolicyKind policy, rclcpp::ParameterValue value, rclcpp::QoS & qos)
+{
+  switch (policy) {
+    case QosPolicyKind::AvoidRosNamespaceConventions:
+      qos.avoid_ros_namespace_conventions(value.get<bool>());
+      break;
+    case QosPolicyKind::Deadline:
+      qos.deadline(::rclcpp::Duration::from_nanoseconds(value.get<int64_t>()));
+      break;
+    case QosPolicyKind::Durability:
+      RCLCPP_DETAIL_APPLY_QOS_OVERRIDE_FROM_PARAMETER_STRING(
+        durability, DURABILITY, value, qos);
+      break;
+    case QosPolicyKind::History:
+      RCLCPP_DETAIL_APPLY_QOS_OVERRIDE_FROM_PARAMETER_STRING(
+        history, HISTORY, value, qos);
+      break;
+    case QosPolicyKind::Depth:
+      qos.get_rmw_qos_profile().depth = static_cast<size_t>(value.get<int64_t>());
+      break;
+    case QosPolicyKind::Lifespan:
+      qos.lifespan(::rclcpp::Duration::from_nanoseconds(value.get<int64_t>()));
+      break;
+    case QosPolicyKind::Liveliness:
+      RCLCPP_DETAIL_APPLY_QOS_OVERRIDE_FROM_PARAMETER_STRING(
+        liveliness, LIVELINESS, value, qos);
+      break;
+    case QosPolicyKind::LivelinessLeaseDuration:
+      qos.liveliness_lease_duration(::rclcpp::Duration::from_nanoseconds(value.get<int64_t>()));
+      break;
+    case QosPolicyKind::Reliability:
+      RCLCPP_DETAIL_APPLY_QOS_OVERRIDE_FROM_PARAMETER_STRING(
+        reliability, RELIABILITY, value, qos);
+      break;
+    default:
+      throw std::invalid_argument{"unknown QosPolicyKind"};
+  }
+}
+
+/// Convert `rmw_time_t` to `int64_t` that can be used as a parameter value.
+inline
+int64_t
+rmw_duration_to_int64_t(rmw_time_t rmw_duration)
+{
+  return ::rclcpp::Duration(
+    static_cast<int32_t>(rmw_duration.sec),
+    static_cast<uint32_t>(rmw_duration.nsec)
+  ).nanoseconds();
+}
+
+/// \internal Throw an exception if `policy_value_stringified` is NULL.
+inline
+const char *
+check_if_stringified_policy_is_null(const char * policy_value_stringified, QosPolicyKind kind)
+{
+  if (!policy_value_stringified) {
+    std::ostringstream oss{"unknown value for policy kind {", std::ios::ate};
+    oss << kind << "}";
+    throw std::invalid_argument{oss.str()};
+  }
+  return policy_value_stringified;
+}
+
+inline
+::rclcpp::ParameterValue
+get_default_qos_param_value(rclcpp::QosPolicyKind kind, const rclcpp::QoS & qos)
+{
+  using ParameterValue = ::rclcpp::ParameterValue;
+  const auto & rmw_qos = qos.get_rmw_qos_profile();
+  switch (kind) {
+    case QosPolicyKind::AvoidRosNamespaceConventions:
+      return ParameterValue(rmw_qos.avoid_ros_namespace_conventions);
+    case QosPolicyKind::Deadline:
+      return ParameterValue(rmw_duration_to_int64_t(rmw_qos.deadline));
+    case QosPolicyKind::Durability:
+      return ParameterValue(
+        check_if_stringified_policy_is_null(
+          rmw_qos_durability_policy_to_str(rmw_qos.durability), kind));
+    case QosPolicyKind::History:
+      return ParameterValue(
+        check_if_stringified_policy_is_null(
+          rmw_qos_history_policy_to_str(rmw_qos.history), kind));
+    case QosPolicyKind::Depth:
+      return ParameterValue(static_cast<int64_t>(rmw_qos.depth));
+    case QosPolicyKind::Lifespan:
+      return ParameterValue(rmw_duration_to_int64_t(rmw_qos.lifespan));
+    case QosPolicyKind::Liveliness:
+      return ParameterValue(
+        check_if_stringified_policy_is_null(
+          rmw_qos_liveliness_policy_to_str(rmw_qos.liveliness), kind));
+    case QosPolicyKind::LivelinessLeaseDuration:
+      return ParameterValue(rmw_duration_to_int64_t(rmw_qos.liveliness_lease_duration));
+    case QosPolicyKind::Reliability:
+      return ParameterValue(
+        check_if_stringified_policy_is_null(
+          rmw_qos_reliability_policy_to_str(rmw_qos.reliability), kind));
+    default:
+      throw std::invalid_argument{"unknown QoS policy kind"};
+  }
+}
+
+}  // namespace detail
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__QOS_PARAMETERS_HPP_

rclcpp/include/rclcpp/detail/resolve_enable_topic_statistics.hpp

@@ -42,7 +42,6 @@ resolve_enable_topic_statistics(const OptionsT & options, const NodeBaseT & node
       break;
     default:
       throw std::runtime_error("Unrecognized EnableTopicStatistics value");
-      break;
   }
 
   return topic_stats_enabled;

rclcpp/include/rclcpp/detail/subscription_callback_type_helper.hpp

@@ -0,0 +1,166 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__DETAIL__SUBSCRIPTION_CALLBACK_TYPE_HELPER_HPP_
+#define RCLCPP__DETAIL__SUBSCRIPTION_CALLBACK_TYPE_HELPER_HPP_
+
+#include <memory>
+#include <type_traits>
+
+#include "rclcpp/function_traits.hpp"
+#include "rclcpp/message_info.hpp"
+
+namespace rclcpp
+{
+namespace detail
+{
+
+/// Template metaprogramming helper used to resolve the callback argument into a std::function.
+/**
+ * Sometimes the CallbackT is a std::function already, but it could also be a
+ * function pointer, lambda, bind, or some variant of those.
+ * In some cases, like a lambda where the arguments can be converted between one
+ * another, e.g. std::function<void (shared_ptr<...>)> and
+ * std::function<void (unique_ptr<...>)>, you need to make that not ambiguous
+ * by checking the arguments independently using function traits rather than
+ * rely on overloading the two std::function types.
+ *
+ * This issue, with the lambda's, can be demonstrated with this minimal program:
+ *
+ * \code{.cpp}
+ *   #include <functional>
+ *   #include <memory>
+ *
+ *   void f(std::function<void (std::shared_ptr<int>)>) {}
+ *   void f(std::function<void (std::unique_ptr<int>)>) {}
+ *
+ *   int main() {
+ *     // Fails to compile with an "ambiguous call" error.
+ *     f([](std::shared_ptr<int>){});
+ *
+ *     // Works.
+ *     std::function<void (std::shared_ptr<int>)> cb = [](std::shared_ptr<int>){};
+ *     f(cb);
+ *   }
+ * \endcode
+ *
+ * If this program ever starts working in a future version of C++, this class
+ * may become redundant.
+ *
+ * This helper works by using SFINAE with rclcpp::function_traits::same_arguments<>
+ * to narrow down the exact std::function<> type for the given CallbackT.
+ */
+template<typename MessageT, typename CallbackT, typename Enable = void>
+struct SubscriptionCallbackTypeHelper
+{
+  using callback_type = typename rclcpp::function_traits::as_std_function<CallbackT>::type;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(std::shared_ptr<const MessageT>)>
+    >::value
+  >
+>
+{
+  using callback_type = std::function<void (std::shared_ptr<const MessageT>)>;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(std::shared_ptr<const MessageT>, const rclcpp::MessageInfo &)>
+    >::value
+  >
+>
+{
+  using callback_type =
+    std::function<void (std::shared_ptr<const MessageT>, const rclcpp::MessageInfo &)>;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(const std::shared_ptr<const MessageT> &)>
+    >::value
+  >
+>
+{
+  using callback_type = std::function<void (const std::shared_ptr<const MessageT> &)>;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(const std::shared_ptr<const MessageT> &, const rclcpp::MessageInfo &)>
+    >::value
+  >
+>
+{
+  using callback_type =
+    std::function<void (const std::shared_ptr<const MessageT> &, const rclcpp::MessageInfo &)>;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(std::shared_ptr<MessageT>)>
+    >::value
+  >
+>
+{
+  using callback_type = std::function<void (std::shared_ptr<MessageT>)>;
+};
+
+template<typename MessageT, typename CallbackT>
+struct SubscriptionCallbackTypeHelper<
+  MessageT,
+  CallbackT,
+  typename std::enable_if_t<
+    rclcpp::function_traits::same_arguments<
+      CallbackT,
+      std::function<void(std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)>
+    >::value
+  >
+>
+{
+  using callback_type =
+    std::function<void (std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)>;
+};
+
+}  // namespace detail
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__SUBSCRIPTION_CALLBACK_TYPE_HELPER_HPP_

rclcpp/include/rclcpp/detail/utilities.hpp

@@ -30,7 +30,7 @@ namespace detail
 
 std::vector<std::string>
 get_unparsed_ros_arguments(
-  int argc, char const * const argv[],
+  int argc, char const * const * argv,
   rcl_arguments_t * arguments,
   rcl_allocator_t allocator);
 

rclcpp/include/rclcpp/duration.hpp

@@ -26,11 +26,19 @@ namespace rclcpp
 class RCLCPP_PUBLIC Duration
 {
 public:
+  /// Duration constructor.
+  /**
+   * Initializes the time values for seconds and nanoseconds individually.
+   * Large values for nsecs are wrapped automatically with the remainder added to secs.
+   * Both inputs must be integers.
+   * Seconds can be negative.
+   *
+   * \param seconds time in seconds
+   * \param nanoseconds time in nanoseconds
+   */
   Duration(int32_t seconds, uint32_t nanoseconds);
 
-  // This constructor matches any numeric value - ints or floats
-  explicit Duration(rcl_duration_value_t nanoseconds);
-
+  /// Construct duration from the specified std::chrono::nanoseconds.
   explicit Duration(std::chrono::nanoseconds nanoseconds);
 
   // This constructor matches any std::chrono value other than nanoseconds
@@ -44,6 +52,10 @@ public:
   // cppcheck-suppress noExplicitConstructor
   Duration(const builtin_interfaces::msg::Duration & duration_msg);  // NOLINT(runtime/explicit)
 
+  /// Time constructor
+  /**
+   * \param duration rcl_duration_t structure to copy.
+   */
   explicit Duration(const rcl_duration_t & duration);
 
   Duration(const Duration & rhs);
@@ -57,11 +69,14 @@ public:
   operator=(const Duration & rhs);
 
   Duration &
-  operator=(const builtin_interfaces::msg::Duration & Duration_msg);
+  operator=(const builtin_interfaces::msg::Duration & duration_msg);
 
   bool
   operator==(const rclcpp::Duration & rhs) const;
 
+  bool
+  operator!=(const rclcpp::Duration & rhs) const;
+
   bool
   operator<(const rclcpp::Duration & rhs) const;
 
@@ -80,6 +95,10 @@ public:
   Duration
   operator-(const rclcpp::Duration & rhs) const;
 
+  /// Get the maximum representable value.
+  /**
+   * \return the maximum representable value
+   */
   static
   Duration
   max();
@@ -87,19 +106,34 @@ public:
   Duration
   operator*(double scale) const;
 
+  /// Get duration in nanosecods
+  /**
+   * \return the duration in nanoseconds as a rcl_duration_value_t.
+   */
   rcl_duration_value_t
   nanoseconds() const;
 
-  /// \return the duration in seconds as a floating point number.
-  /// \warning Depending on sizeof(double) there could be significant precision loss.
-  /// When an exact time is required use nanoseconds() instead.
+  /// Get duration in seconds
+  /**
+   * \warning Depending on sizeof(double) there could be significant precision loss.
+   *   When an exact time is required use nanoseconds() instead.
+   * \return the duration in seconds as a floating point number.
+   */
   double
   seconds() const;
 
-  // Create a duration object from a floating point number representing seconds
+  /// Create a duration object from a floating point number representing seconds
   static Duration
   from_seconds(double seconds);
 
+  /// Create a duration object from an integer number representing nanoseconds
+  static Duration
+  from_nanoseconds(rcl_duration_value_t nanoseconds);
+
+  static Duration
+  from_rmw_time(rmw_time_t duration);
+
+  /// Convert Duration into a std::chrono::Duration.
   template<class DurationT>
   DurationT
   to_chrono() const
@@ -107,11 +141,14 @@ public:
     return std::chrono::duration_cast<DurationT>(std::chrono::nanoseconds(this->nanoseconds()));
   }
 
+  /// Convert Duration into rmw_time_t.
   rmw_time_t
   to_rmw_time() const;
 
 private:
   rcl_duration_t rcl_duration_;
+
+  Duration() = default;
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/event.hpp

@@ -29,17 +29,33 @@ class Event
 public:
   RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(Event)
 
+  /// Default construct
+  /**
+   * Set the default value to false
+   */
   RCLCPP_PUBLIC
   Event();
 
+  /// Set the Event state value to true
+  /**
+   * \return The state value before the call.
+   */
   RCLCPP_PUBLIC
   bool
   set();
 
+  /// Get the state value of the Event
+  /**
+   * \return the Event state value
+   */
   RCLCPP_PUBLIC
   bool
   check();
 
+  /// Get the state value of the Event and set to false
+  /**
+   * \return the Event state value
+   */
   RCLCPP_PUBLIC
   bool
   check_and_clear();

rclcpp/include/rclcpp/exceptions/exceptions.hpp

@@ -100,6 +100,17 @@ public:
   {}
 };
 
+class UnimplementedError : public std::runtime_error
+{
+public:
+  UnimplementedError()
+  : std::runtime_error("This code is unimplemented.") {}
+  explicit UnimplementedError(const std::string & msg)
+  : std::runtime_error(msg) {}
+};
+
+typedef void (* reset_error_function_t)();
+
 /// Throw a C++ std::exception which was created based on an rcl error.
 /**
  * Passing nullptr for reset_error is safe and will avoid calling any function
@@ -120,7 +131,7 @@ throw_from_rcl_error [[noreturn]] (
   rcl_ret_t ret,
   const std::string & prefix = "",
   const rcl_error_state_t * error_state = nullptr,
-  void (* reset_error)() = rcl_reset_error);
+  reset_error_function_t reset_error = rcl_reset_error);
 /* *INDENT-ON* */
 
 class RCLErrorBase
@@ -245,6 +256,23 @@ public:
   {}
 };
 
+/// Thrown if user attempts to create an uninitialized statically typed parameter
+/**
+ * (see https://github.com/ros2/rclcpp/issues/1691)
+ */
+class UninitializedStaticallyTypedParameterException : public std::runtime_error
+{
+public:
+  /// Construct an instance.
+  /**
+   * \param[in] name the name of the parameter.
+   */
+  RCLCPP_PUBLIC
+  explicit UninitializedStaticallyTypedParameterException(const std::string & name)
+  : std::runtime_error("Statically typed parameter '" + name + "' must be initialized.")
+  {}
+};
+
 /// Thrown if parameter is already declared.
 class ParameterAlreadyDeclaredException : public std::runtime_error
 {
@@ -273,6 +301,33 @@ class ParameterModifiedInCallbackException : public std::runtime_error
   using std::runtime_error::runtime_error;
 };
 
+/// Thrown when an uninitialized parameter is accessed.
+class ParameterUninitializedException : public std::runtime_error
+{
+public:
+  /// Construct an instance.
+  /**
+   * \param[in] name the name of the parameter.
+   */
+  explicit ParameterUninitializedException(const std::string & name)
+  : std::runtime_error("parameter '" + name + "' is not initialized")
+  {}
+};
+
+/// Thrown if the QoS overrides provided aren't valid.
+class InvalidQosOverridesException : public std::runtime_error
+{
+  // Inherit constructors from runtime_error.
+  using std::runtime_error::runtime_error;
+};
+
+/// Thrown if a QoS compatibility check fails.
+class QoSCheckCompatibleException : public std::runtime_error
+{
+  // Inherit constructors from runtime_error.
+  using std::runtime_error::runtime_error;
+};
+
 }  // namespace exceptions
 }  // namespace rclcpp
 

rclcpp/include/rclcpp/executor.hpp

@@ -21,6 +21,7 @@
 #include <cstdlib>
 #include <iostream>
 #include <list>
+#include <map>
 #include <memory>
 #include <mutex>
 #include <string>
@@ -28,242 +29,219 @@
 
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
+#include "rcpputils/scope_exit.hpp"
 
-#include "rclcpp/callback_group.hpp"
-#include "rclcpp/executor_options.hpp"
-#include "rclcpp/executor_policies/timer_favoring_priority_queue.hpp"
-#include "rclcpp/future_return_code.hpp"
+#include "rclcpp/context.hpp"
+#include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/guard_condition.hpp"
+#include "rclcpp/executor_options.hpp"
+#include "rclcpp/future_return_code.hpp"
 #include "rclcpp/memory_strategies.hpp"
 #include "rclcpp/memory_strategy.hpp"
 #include "rclcpp/node_interfaces/node_base_interface.hpp"
 #include "rclcpp/utilities.hpp"
 #include "rclcpp/visibility_control.hpp"
-#include "rclcpp/wait_set.hpp"
 
 namespace rclcpp
 {
 
-/// Base class for Executor providing the common interface for adding items, spinning, etc.
-class ExecutorBase
+typedef std::map<rclcpp::CallbackGroup::WeakPtr,
+    rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
+    std::owner_less<rclcpp::CallbackGroup::WeakPtr>> WeakCallbackGroupsToNodesMap;
+
+// Forward declaration is used in convenience method signature.
+class Node;
+
+/// Coordinate the order and timing of available communication tasks.
+/**
+ * Executor provides spin functions (including spin_node_once and spin_some).
+ * It coordinates the nodes and callback groups by looking for available work and completing it,
+ * based on the threading or concurrency scheme provided by the subclass implementation.
+ * An example of available work is executing a subscription callback, or a timer callback.
+ * The executor structure allows for a decoupling of the communication graph and the execution
+ * model.
+ * See SingleThreadedExecutor and MultiThreadedExecutor for examples of execution paradigms.
+ */
+class Executor
 {
 public:
-  RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(ExecutorBase)
+  RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(Executor)
 
   /// Default constructor.
   /**
-   * \param[in] options Options for the executor.
+   * \param[in] options Options used to configure the executor.
    */
   RCLCPP_PUBLIC
-  explicit ExecutorBase(const ExecutorOptions & options = ExecutorOptions());
+  explicit Executor(const rclcpp::ExecutorOptions & options = rclcpp::ExecutorOptions());
 
   /// Default destructor.
   RCLCPP_PUBLIC
-  virtual ~ExecutorBase();
+  virtual ~Executor();
 
-  /// Execution loop which waits for work, executes work, and repeats until canceled.
-  /**
-   * This will block, continuing to wait for work and then execute it, until
-   * canceled, either by the cancel() method or by the associated context being
-   * shutdown, either explicitly or due to a SIGINT (perhaps due to ctrl-c).
-   */
-  virtual
-  void
+  /// Do work periodically as it becomes available to us. Blocking call, may block indefinitely.
+  // It is up to the implementation of Executor to implement spin.
+  virtual void
   spin() = 0;
 
-  /// Add all of a node's callback groups to the executor.
+  /// Add a callback group to an executor.
   /**
-   * Add all of the callback groups of a node to this executor.
+   * An executor can have zero or more callback groups which provide work during `spin` functions.
+   * When an executor attempts to add a callback group, the executor checks to see if it is already
+   * associated with another executor, and if it has been, then an exception is thrown.
+   * Otherwise, the callback group is added to the executor.
    *
-   * If any callback groups are associated with another executor, this method
-   * will throw a std::runtime_error.
+   * Adding a callback group with this method does not associate its node with this executor
+   * in any way
    *
-   * It will also trigger the interrupt guard condition which will cause the
-   * executor to wake up and consider the changes, then go back to waiting.
-   * Unless the notify parameter is passed false, in which case it will not
-   * interrupt the executor, and the changes may not be considered immediately.
-   *
-   * \param[in] node_ptr Shared pointer to the node which will have callback groups added.
-   * \param[in] notify If true, notfiy the executor of changes, otherwise do not.
-   * \throws std::runtime_error if any callback groups are associated with another executor.
-   */
-  template<class NodeT>
-  void
-  add_node(const std::shared_ptr<NodeT> & node_ptr, bool notify = true)
-  {
-    this->add_node(
-      node_ptr->get_node_base_interface(),
-      notify,
-      false  // raise on encountering already associated callback groups
-    );
-  }
-
-  /// Overload that takes the NodeBaseInterface directly.
-  template<class NodeT>
-  void
-  add_node(
-    const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr & node_ptr,
-    bool notify = true)
-  {
-    this->add_node(
-      node_ptr,
-      notify,
-      false  // raise on encountering already associated callback groups
-    );
-  }
-
-  /// Add all unassociated callback groups of the given node to this executor.
-  /**
-   * Same as add_node(), but instead of throwing if a callback group is already
-   * associated with another exector (already added to it) it will just ignore
-   * it rather than throwing.
-   *
-   * \param[in] node_ptr Shared pointer to the node which will have callback groups added.
-   * \param[in] notify If true, notfiy the executor of changes, otherwise do not.
-   */
-  template<class NodeT>
-  void
-  add_unassociated_callback_groups_from_node(
-    const std::shared_ptr<NodeT> & node_ptr,
-    bool notify = true)
-  {
-    this->add_node(
-      node_ptr->get_node_base_interface(),
-      notify,
-      true  // ignore already associated callback groups
-    );
-  }
-
-  /// Overload that takes the NodeBaseInterface directly.
-  template<class NodeT>
-  void
-  add_unassociated_callback_groups_from_node(
-    const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr & node_ptr,
-    bool notify = true)
-  {
-    this->add_node(
-      node_ptr,
-      notify,
-      true  // ignore already associated callback groups
-    );
-  }
-
-  /// Remove all of a node's callback groups from the executor.
-  /**
-   * Remove all of the callback groups of a node from this executor.
-   *
-   * It will also trigger the interrupt guard condition which will cause the
-   * executor to wake up and consider the changes, then go back to waiting.
-   * Unless the notify parameter is passed false, in which case it will not
-   * interrupt the executor, and the changes may not be considered immediately.
-   *
-   * \param[in] node Node which will have callback groups removed.
-   * \param[in] notify If true, notfiy the executor of changes, otherwise do not.
-   */
-  template<class NodeT>
-  void
-  remove_node(const NodeT & node, bool notify = true)
-  {
-    this->remove_node(*node.get_node_base_interface(), notify);
-  }
-
-  /// Overload that takes a shared pointer to the node.
-  /**
-   * This is kept for backwards compatibility from when executors shared
-   * ownership of Nodes.
-   */
-  template<class NodeT>
-  void
-  remove_node(const std::shared_ptr<NodeT> & node_ptr, bool notify = true)
-  {
-    this->remove_node(*node_ptr->get_node_base_interface(), notify);
-  }
-
-  /// Placeholder used to indicate that a method overload should not notify the executor.
-  struct DoNotNotify {};
-
-  /// Add a callback group to this executor.
-  /**
-   * If the given callback group is already associated with another executor,
-   * this method will throw a std::runtime_error.
-   *
-   * This overload of add_callback_group() will notify the executor so it will
-   * wake up if waiting and consider the changes.
-   *
-   * Weak ownership of the callback group is kept by the executor all of the
-   * time, but while waiting the weak ownership is periodically elevated to
-   * shared ownership.
-   * Therefore, if you let the callback group shared pointer go out of scope
-   * then it will stay in scope until this executor is done using it, at which
-   * point the callback group will be destructed and automatically removed from
-   * this executor in the next pass.
-   *
-   * \param[in] callback_group_ptr The callback group to be added.
-   * \throws std::runtime_error if the callback group is associated with another
-   *   executor already.
-   * \throws std::invalid_argument if the callback group pointer is nullptr.
+   * \param[in] group_ptr a shared ptr that points to a callback group
+   * \param[in] node_ptr a shared pointer that points to a node base interface
+   * \param[in] notify True to trigger the interrupt guard condition during this function. If
+   * the executor is blocked at the rmw layer while waiting for work and it is notified that a new
+   * callback group was added, it will wake up.
+   * \throw std::runtime_error if the callback group is associated to an executor
    */
   RCLCPP_PUBLIC
-  virtual
-  void
-  add_callback_group(rclcpp::CallbackGroup::SharedPtr callback_group_ptr) = 0;
+  virtual void
+  add_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    bool notify = true);
 
-  /// Add a callback group to this executor without notifying the executor.
+  /// Get callback groups that belong to executor.
   /**
-   * The same as the other overload of add_callback_group(), except it does not
-   * notify the executor, so it will not wake up and these changes may not be
-   * considered immediately.
+   * This function returns a vector of weak pointers that point to callback groups that were
+   * associated with the executor.
+   * The callback groups associated with this executor may have been added with
+   * `add_callback_group`, or added when a node was added to the executor with `add_node`, or
+   * automatically added when it created by a node already associated with this executor and the
+   * automatically_add_to_executor_with_node parameter was true.
    *
-   * Note, a bool with a default value would be preferable for controlling the
-   * notify behavior, and we're using it in the add/remove node above, but
-   * in order to keep this function virtual, and to avoid using default values
-   * in conjunction with virtual methods, we use an overload instead, in the
-   * spirit of std::nothrow_t, e.g.:
-   *   https://en.cppreference.com/w/cpp/memory/new/nothrow
+   * \return a vector of weak pointers that point to callback groups that are associated with
+   * the executor
    */
   RCLCPP_PUBLIC
-  virtual
-  void
-  add_callback_group(rclcpp::CallbackGroup::SharedPtr callback_group_ptr, DoNotNotify) = 0;
+  virtual std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_all_callback_groups();
 
-  /// Remove a callback group from this executor.
+  /// Get callback groups that belong to executor.
   /**
-   * If the given callback group is not associated with this executor, this
-   * method will throw a std::runtime_error.
+   * This function returns a vector of weak pointers that point to callback groups that were
+   * associated with the executor.
+   * The callback groups associated with this executor have been added with
+   * `add_callback_group`.
    *
-   * This overload of add_callback_group() will notify the executor so it will
-   * wake up if waiting and consider the changes.
-   *
-   * \param[in] callback_group The callback group to be removed.
-   * \throws std::runtime_error if the callback group is not associated with
-   *   this executor.
-   * \throws std::invalid_argument if the callback group pointer is nullptr.
+   * \return a vector of weak pointers that point to callback groups that are associated with
+   * the executor
    */
   RCLCPP_PUBLIC
-  virtual
-  void
-  remove_callback_group(const rclcpp::CallbackGroup & callback_group) = 0;
+  virtual std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_manually_added_callback_groups();
 
-  /// Remove a callback group from this executor without notifying the executor.
+  /// Get callback groups that belong to executor.
   /**
-   * The same as the other overload of remove_callback_group(), except it does not
-   * notify the executor, so it will not wake up and these changes may not be
-   * considered immediately.
+   * This function returns a vector of weak pointers that point to callback groups that were
+   * added from a node that is associated with the executor.
+   * The callback groups are added when a node is added to the executor with `add_node`, or
+   * automatically if they are created in the future by that node and have the
+   * automatically_add_to_executor_with_node argument set to true.
    *
-   * See add_callback_group() for a note about the use of DoNotNotify.
+   * \return a vector of weak pointers that point to callback groups from a node associated with
+   * the executor
    */
   RCLCPP_PUBLIC
-  virtual
-  void
-  remove_callback_group(const rclcpp::CallbackGroup & callback_group, DoNotNotify) = 0;
+  virtual std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_automatically_added_callback_groups_from_nodes();
+
+  /// Remove a callback group from the executor.
+  /**
+   * The callback group is removed from and disassociated with the executor.
+   * If the callback group removed was the last callback group from the node
+   * that is associated with the executor, the interrupt guard condition
+   * is triggered and node's guard condition is removed from the executor.
+   *
+   * This function only removes a callback group that was manually added with
+   * rclcpp::Executor::add_callback_group.
+   * To remove callback groups that were added from a node using
+   * rclcpp::Executor::add_node, use rclcpp::Executor::remove_node instead.
+   *
+   * \param[in] group_ptr Shared pointer to the callback group to be added.
+   * \param[in] notify True to trigger the interrupt guard condition during this function. If
+   * the executor is blocked at the rmw layer while waiting for work and it is notified that a
+   * callback group was removed, it will wake up.
+   * \throw std::runtime_error if node is deleted before callback group
+   * \throw std::runtime_error if the callback group is not associated with the executor
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  remove_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    bool notify = true);
+
+  /// Add a node to the executor.
+  /**
+   * Nodes have associated callback groups, and this method adds any of those callback groups
+   * to this executor which have their automatically_add_to_executor_with_node parameter true.
+   * The node is also associated with the executor so that future callback groups which are
+   * created on the node with the automatically_add_to_executor_with_node parameter set to true
+   * are also automatically associated with this executor.
+   *
+   * Callback groups with the automatically_add_to_executor_with_node parameter set to false must
+   * be manually added to an executor using the rclcpp::Executor::add_callback_group method.
+   *
+   * If a node is already associated with an executor, this method throws an exception.
+   *
+   * \param[in] node_ptr Shared pointer to the node to be added.
+   * \param[in] notify True to trigger the interrupt guard condition during this function. If
+   * the executor is blocked at the rmw layer while waiting for work and it is notified that a new
+   * node was added, it will wake up.
+   * \throw std::runtime_error if a node is already associated to an executor
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  add_node(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr, bool notify = true);
+
+  /// Convenience function which takes Node and forwards NodeBaseInterface.
+  /**
+   * \see rclcpp::Executor::add_node
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  add_node(std::shared_ptr<rclcpp::Node> node_ptr, bool notify = true);
+
+  /// Remove a node from the executor.
+  /**
+   * Any callback groups automatically added when this node was added with
+   * rclcpp::Executor::add_node are automatically removed, and the node is no longer associated
+   * with this executor.
+   *
+   * This also means that future callback groups created by the given node are no longer
+   * automatically added to this executor.
+   *
+   * \param[in] node_ptr Shared pointer to the node to remove.
+   * \param[in] notify True to trigger the interrupt guard condition and wake up the executor.
+   * This is useful if the last node was removed from the executor while the executor was blocked
+   * waiting for work in another thread, because otherwise the executor would never be notified.
+   * \throw std::runtime_error if the node is not associated with an executor.
+   * \throw std::runtime_error if the node is not associated with this executor.
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  remove_node(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr, bool notify = true);
+
+  /// Convenience function which takes Node and forwards NodeBaseInterface.
+  /**
+   * \see rclcpp::Executor::remove_node
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  remove_node(std::shared_ptr<rclcpp::Node> node_ptr, bool notify = true);
 
   /// Add a node to executor, execute the next available unit of work, and remove the node.
   /**
    * \param[in] node Shared pointer to the node to add.
-   * \param[in] timeout How long to wait for work to become available.
-   *   Negative values cause spin_node_once to block indefinitely (the default
-   *   behavior).
-   *   A timeout of 0 causes this function to be non-blocking.
+   * \param[in] timeout How long to wait for work to become available. Negative values cause
+   * spin_node_once to block indefinitely (the default behavior). A timeout of 0 causes this
+   * function to be non-blocking.
    */
   template<typename RepT = int64_t, typename T = std::milli>
   void
@@ -278,7 +256,7 @@ public:
   }
 
   /// Convenience function which takes Node and forwards NodeBaseInterface.
-  template<typename NodeT, typename RepT = int64_t, typename T = std::milli>
+  template<typename NodeT = rclcpp::Node, typename RepT = int64_t, typename T = std::milli>
   void
   spin_node_once(
     std::shared_ptr<NodeT> node,
@@ -292,16 +270,18 @@ public:
 
   /// Add a node, complete all immediately available work, and remove the node.
   /**
-   * \param[in] node Shared pointer to the node to spin some.
+   * \param[in] node Shared pointer to the node to add.
    */
-  template<class NodeT>
+  RCLCPP_PUBLIC
   void
-  spin_node_some(const std::shared_ptr<NodeT> & node)
-  {
-    this->spin_node_some(node->get_node_base_interface());
-  }
+  spin_node_some(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node);
 
-  /// Complete all available queued work without blocking.
+  /// Convenience function which takes Node and forwards NodeBaseInterface.
+  RCLCPP_PUBLIC
+  void
+  spin_node_some(std::shared_ptr<rclcpp::Node> node);
+
+  /// Collect work once and execute all available work, optionally within a duration.
   /**
    * This function can be overridden. The default implementation is suitable for a
    * single-threaded model of execution.
@@ -313,14 +293,31 @@ public:
    * been exceeded.
    */
   RCLCPP_PUBLIC
-  virtual
-  void
-  spin_some(std::chrono::nanoseconds max_duration = std::chrono::nanoseconds(0)) = 0;
+  virtual void
+  spin_some(std::chrono::nanoseconds max_duration = std::chrono::nanoseconds(0));
+
+  /// Collect and execute work repeatedly within a duration or until no more work is available.
+  /**
+   * This function can be overridden. The default implementation is suitable for a
+   * single-threaded model of execution.
+   * Adding subscriptions, timers, services, etc. with blocking callbacks will cause this function
+   * to block (which may have unintended consequences).
+   * If the time that waitables take to be executed is longer than the period on which new waitables
+   * become ready, this method will execute work repeatedly until `max_duration` has elapsed.
+   *
+   * \param[in] max_duration The maximum amount of time to spend executing work, must be >= 0.
+   *   `0` is potentially block forever until no more work is available.
+   * \throw std::invalid_argument if max_duration is less than 0.
+   * Note that spin_all() may take longer than this time as it only returns once max_duration has
+   * been exceeded.
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  spin_all(std::chrono::nanoseconds max_duration);
 
   RCLCPP_PUBLIC
-  virtual
-  void
-  spin_once(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1)) = 0;
+  virtual void
+  spin_once(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1));
 
   /// Spin (blocking) until the future is complete, it times out waiting, or rclcpp is interrupted.
   /**
@@ -332,10 +329,10 @@ public:
    *   code.
    * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
    */
-  template<typename ResponseT, typename TimeRepT = int64_t, typename TimeT = std::milli>
+  template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
   FutureReturnCode
   spin_until_future_complete(
-    const std::shared_future<ResponseT> & future,
+    const FutureT & future,
     std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
   {
     // TODO(wjwwood): does not work recursively; can't call spin_node_until_future_complete
@@ -356,9 +353,14 @@ public:
     }
     std::chrono::nanoseconds timeout_left = timeout_ns;
 
-    while (rclcpp::ok(this->context_)) {
+    if (spinning.exchange(true)) {
+      throw std::runtime_error("spin_until_future_complete() called while already spinning");
+    }
+    RCPPUTILS_SCOPE_EXIT(this->spinning.store(false); );
+    while (rclcpp::ok(this->context_) && spinning.load()) {
       // Do one item of work.
-      spin_once(timeout_left);
+      spin_once_impl(timeout_left);
+
       // Check if the future is set, return SUCCESS if it is.
       status = future.wait_for(std::chrono::seconds(0));
       if (status == std::future_status::ready) {
@@ -383,40 +385,34 @@ public:
 
   /// Cancel any running spin* function, causing it to return.
   /**
-   * This function can be called asynchronously from any thread.
+   * This function can be called asynchonously from any thread.
+   * \throws std::runtime_error if there is an issue triggering the guard condition
    */
   RCLCPP_PUBLIC
-  virtual
   void
-  cancel() = 0;
+  cancel();
+
+  /// Support dynamic switching of the memory strategy.
+  /**
+   * Switching the memory strategy while the executor is spinning in another threading could have
+   * unintended consequences.
+   * \param[in] memory_strategy Shared pointer to the memory strategy to set.
+   * \throws std::runtime_error if memory_strategy is null
+   */
+  RCLCPP_PUBLIC
+  void
+  set_memory_strategy(memory_strategy::MemoryStrategy::SharedPtr memory_strategy);
+
+  /// Returns true if the executor is currently spinning.
+  /**
+   * This function can be called asynchronously from any thread.
+   * \return True if the executor is currently spinning.
+   */
+  RCLCPP_PUBLIC
+  bool
+  is_spinning();
 
 protected:
-  /// Implementation of add_node().
-  /**
-   * \param[in] node_ptr The node which will have its callback groups added.
-   * \param[in] notify If true, the executor is interrupted to consider the
-   *   changes, otherwise it is not interrupted.
-   * \param[in] ignore_associated_callback_groups If true, then when a callback
-   *   group which is already been added to another executor is encountered
-   *   it will be ignored, if false then std::runtime_error is thrown instead.
-   * \throws std::runtime_error if ignore_associated_callback_groups is false
-   *   and a callback group which is already associated with another executor
-   *   is encountered.
-   * \throws std::invalid_argument if node_ptr is nullptr.
-   */
-  RCLCPP_PUBLIC
-  virtual
-  void
-  add_node(
-    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
-    bool notify,
-    bool ignore_associated_callback_groups) = 0;
-
-  RCLCPP_PUBLIC
-  virtual
-  void
-  remove_node(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr, bool notify) = 0;
-
   RCLCPP_PUBLIC
   void
   spin_node_once_nanoseconds(
@@ -424,142 +420,175 @@ protected:
     std::chrono::nanoseconds timeout);
 
   RCLCPP_PUBLIC
-  virtual
   void
-  spin_node_some(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node);
+  spin_some_impl(std::chrono::nanoseconds max_duration, bool exhaustive);
 
   /// Find the next available executable and do the work associated with it.
-  /** \param[in] any_exec Union structure that can hold any executable type (timer, subscription,
+  /**
+   * \param[in] any_exec Union structure that can hold any executable type (timer, subscription,
    * service, client).
+   * \throws std::runtime_error if there is an issue triggering the guard condition
    */
   RCLCPP_PUBLIC
   void
-  execute_any_executable(rclcpp::AnyExecutable & any_exec);
+  execute_any_executable(AnyExecutable & any_exec);
 
   RCLCPP_PUBLIC
-  static
-  void
+  static void
   execute_subscription(
     rclcpp::SubscriptionBase::SharedPtr subscription);
 
   RCLCPP_PUBLIC
-  static
-  void
+  static void
   execute_timer(rclcpp::TimerBase::SharedPtr timer);
 
   RCLCPP_PUBLIC
-  static
-  void
+  static void
   execute_service(rclcpp::ServiceBase::SharedPtr service);
 
   RCLCPP_PUBLIC
-  static
-  void
+  static void
   execute_client(rclcpp::ClientBase::SharedPtr client);
 
+  /**
+   * \throws std::runtime_error if the wait set can be cleared
+   */
   RCLCPP_PUBLIC
   void
   wait_for_work(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1));
 
+  RCLCPP_PUBLIC
+  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr
+  get_node_by_group(
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
+    rclcpp::CallbackGroup::SharedPtr group);
+
+  /// Return true if the node has been added to this executor.
+  /**
+   * \param[in] node_ptr a shared pointer that points to a node base interface
+   * \param[in] weak_groups_to_nodes map to nodes to lookup
+   * \return true if the node is associated with the executor, otherwise false
+   */
+  RCLCPP_PUBLIC
+  bool
+  has_node(
+    const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) const;
+
   RCLCPP_PUBLIC
   rclcpp::CallbackGroup::SharedPtr
   get_group_by_timer(rclcpp::TimerBase::SharedPtr timer);
 
+  /// Add a callback group to an executor
+  /**
+   * \see rclcpp::Executor::add_callback_group
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  add_callback_group_to_map(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
+    bool notify = true) RCPPUTILS_TSA_REQUIRES(mutex_);
+
+  /// Remove a callback group from the executor.
+  /**
+   * \see rclcpp::Executor::remove_callback_group
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  remove_callback_group_from_map(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
+    bool notify = true) RCPPUTILS_TSA_REQUIRES(mutex_);
+
   RCLCPP_PUBLIC
   bool
-  get_next_ready_executable(rclcpp::AnyExecutable & any_executable);
+  get_next_ready_executable(AnyExecutable & any_executable);
+
+  RCLCPP_PUBLIC
+  bool
+  get_next_ready_executable_from_map(
+    AnyExecutable & any_executable,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   RCLCPP_PUBLIC
   bool
   get_next_executable(
-    rclcpp::AnyExecutable & any_executable,
+    AnyExecutable & any_executable,
     std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1));
 
-  RCLCPP_DISABLE_COPY(ExecutorBase)
+  /// Add all callback groups that can be automatically added from associated nodes.
+  /**
+   * The executor, before collecting entities, verifies if any callback group from
+   * nodes associated with the executor, which is not already associated to an executor,
+   * can be automatically added to this executor.
+   * This takes care of any callback group that has been added to a node but not explicitly added
+   * to the executor.
+   * It is important to note that in order for the callback groups to be automatically added to an
+   * executor through this function, the node of the callback groups needs to have been added
+   * through the `add_node` method.
+   */
+  RCLCPP_PUBLIC
+  virtual void
+  add_callback_groups_from_nodes_associated_to_executor() RCPPUTILS_TSA_REQUIRES(mutex_);
 
   /// Spinning state, used to prevent multi threaded calls to spin and to cancel blocking spins.
   std::atomic_bool spinning;
 
   /// Guard condition for signaling the rmw layer to wake up for special events.
   rclcpp::GuardCondition interrupt_guard_condition_;
-  // rcl_guard_condition_t interrupt_guard_condition_ = rcl_get_zero_initialized_guard_condition();
 
-  // /// Wait set for managing entities that the rmw layer waits on.
-  // rcl_wait_set_t wait_set_ = rcl_get_zero_initialized_wait_set();
+  std::shared_ptr<rclcpp::GuardCondition> shutdown_guard_condition_;
 
-  // // Mutex to protect the subsequent memory_strategy_.
-  // std::mutex memory_strategy_mutex_;
+  /// Wait set for managing entities that the rmw layer waits on.
+  rcl_wait_set_t wait_set_ = rcl_get_zero_initialized_wait_set();
 
-  // /// The memory strategy: an interface for handling user-defined memory allocation strategies.
-  // memory_strategy::MemoryStrategy::SharedPtr memory_strategy_;
+  // Mutex to protect the subsequent memory_strategy_.
+  mutable std::mutex mutex_;
+
+  /// The memory strategy: an interface for handling user-defined memory allocation strategies.
+  memory_strategy::MemoryStrategy::SharedPtr
+  memory_strategy_ RCPPUTILS_TSA_PT_GUARDED_BY(mutex_);
 
   /// The context associated with this executor.
-  rclcpp::Context::SharedPtr context_;
+  std::shared_ptr<rclcpp::Context> context_;
 
-  // std::list<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr> weak_nodes_;
-  // std::list<const rcl_guard_condition_t *> guard_conditions_;
-  std::vector<rclcpp::CallbackGroup::WeakPtr> weak_guard_conditions_;
+  RCLCPP_DISABLE_COPY(Executor)
 
-};
-
-/// Template class which serves as the foundation of actual executors.
-/**
- * This class combines the wait set, scheduling policy, and the ExecutorBase
- * class, and implements all of the pure virtual functions of ExecutorBase
- * making it a concrete class.
- */
-template<class WaitSetT, class SchedulingPolicy>
-class ExecutorTemplate : public ExecutorBase, public SchedulingPolicy
-{
-public:
-  RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(ExecutorTemplate)
-
-  /// Default constructor.
-  /**
-   * \param[in] options Options for the executor.
-   */
-  explicit ExecutorTemplate(const ExecutorOptions & options = ExecutorOptions())
-  : ExecutorBase(options), SchedulingPolicy(options), WaitSetT(options.context)
-  {}
-
-  /// Default virtual destructor.
   RCLCPP_PUBLIC
-  virtual
-  ~ExecutorTemplate() = default;
+  virtual void
+  spin_once_impl(std::chrono::nanoseconds timeout);
 
-protected:
-  WaitSetT wait_set_;
+  typedef std::map<rclcpp::CallbackGroup::WeakPtr,
+      const rclcpp::GuardCondition *,
+      std::owner_less<rclcpp::CallbackGroup::WeakPtr>>
+    WeakCallbackGroupsToGuardConditionsMap;
+
+  /// maps callback groups to guard conditions
+  WeakCallbackGroupsToGuardConditionsMap
+  weak_groups_to_guard_conditions_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
+
+  /// maps callback groups associated to nodes
+  WeakCallbackGroupsToNodesMap
+  weak_groups_associated_with_executor_to_nodes_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
+
+  /// maps callback groups to nodes associated with executor
+  WeakCallbackGroupsToNodesMap
+  weak_groups_to_nodes_associated_with_executor_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
+
+  /// maps all callback groups to nodes
+  WeakCallbackGroupsToNodesMap
+  weak_groups_to_nodes_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
+
+  /// nodes that are associated with the executor
+  std::list<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr>
+  weak_nodes_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
+
+  /// shutdown callback handle registered to Context
+  rclcpp::OnShutdownCallbackHandle shutdown_callback_handle_;
 };
 
-/// Executor concept which waits for work and coordinates execution of user callbacks.
-/**
- * Executor provides spin functions (including spin_node_once and spin_some).
- * It coordinates the nodes and callback groups by looking for available work
- * and completing it, based on the threading or concurrency scheme provided by
- * the subclass implementation.
- * An example of available work is executing a subscription callback, or a
- * timer callback.
- * The executor structure allows for a decoupling of the communication graph
- * and the execution model.
- * See SingleThreadedExecutor and MultiThreadedExecutor for examples of
- * different execution paradigms.
- *
- * By default this alias provides a foundation based on specific wait set type
- * and a scheduling policy.
- * The wait set is expected to be dynamic, i.e. items can be added or removed
- * after creation, and thread-safe, i.e. items can be added or removed while
- * also waiting concurrently.
- */
-using Executor = ExecutorTemplate<
-  rclcpp::ThreadSafeWaitSet,
-  rclcpp::executor_policies::TimerFavoringPriorityQueue>;
-
-namespace executor
-{
-
-using Executor [[deprecated("use rclcpp::Executor instead")]] = Executor;
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__EXECUTOR_HPP_

rclcpp/include/rclcpp/executor_options.hpp

@@ -1,4 +1,4 @@
-// Copyright 2014 Open Source Robotics Foundation, Inc.
+// Copyright 2014-2020 Open Source Robotics Foundation, Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -38,12 +38,6 @@ struct ExecutorOptions
   size_t max_conditions;
 };
 
-namespace executor
-{
-
-using ExecutorArgs [[deprecated("use rclcpp::ExecutorOptions instead")]] = ExecutorOptions;
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__EXECUTOR_OPTIONS_HPP_

rclcpp/include/rclcpp/executor_policies/timer_favoring_priority_queue.hpp

@@ -1,77 +0,0 @@
-// Copyright 2020 Open Source Robotics Foundation, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef RCLCPP__EXECUTOR_POLICIES__TIMER_FAVORING_PRIORITY_QUEUE_HPP_
-#define RCLCPP__EXECUTOR_POLICIES__TIMER_FAVORING_PRIORITY_QUEUE_HPP_
-
-#include "rclcpp/any_executable.hpp"
-#include "rclcpp/executor_options.hpp"
-#include "rclcpp/executor_policies/scheduling_result.hpp"
-#include "rclcpp/visibility_control.hpp"
-#include "rclcpp/wait_result.hpp"
-
-namespace rclcpp
-{
-namespace executor_policies
-{
-
-/// A naive scheduling policy which selects Timers first, then Subscriptions and other items.
-/**
- * Items are executed in the order they were added, favoring Timers, then
- * Subscriptions, Service Servers, Service Clients, and finally Waitables.
- * All Timers are executed before any Subscriptions, and all Subscriptions
- * before any Service Servers, and so on.
- *
- * User guard conditions are not yet supported by the Executor and so all guard
- * condition are used by the executor itself and are handled before this policy
- * is consulted.
- * Therefore, guard conditions are ignored for the purposes of scheduling.
- *
- * This is a naive policy, but is the default until a better one is implemented.
- */
-class TimerFavoringPriorityQueue
-{
-public:
-  explicit TimerFavoringPriorityQueue(const rclcpp::ExecutorOptions &) {}
-
-  /// Select which item should next be executed, and indicate if waiting should resume.
-  /**
-   * Selects which item to be executed next, assign it to the any_executable, or
-   * assigning nullptr if no work should be done right now.
-   *
-   * This method is called by the executor after waiting on a wait set, in
-   * order to determine what to execute next based on the result.
-   *
-   * Additionally, if returning SchedulingResult::ContinueExecuting then the
-   * executor will call this function again without waiting on the wait set, or
-   * if returning SchedulingResult::WaitForWork then the executor will wait on
-   * the wait set again after executing the selected any_executable, or
-   * immediately if any_executable was assigned nullptr.
-   */
-  template<class WaitSetT>
-  rclcpp::executor_policies::SchedulingResult
-  schedule_next_any_executable(
-    const WaitResult<WaitSetT> & wait_result,
-    rclcpp::AnyExecutable & any_executable)
-  {
-    // Explicitly ignore guard conditions.
-    // Check Timers for being ready.
-
-  }
-};
-
-}  // namespace executor_policies
-}  // namespace rclcpp
-
-#endif  // RCLCPP__EXECUTOR_POLICIES__TIMER_FAVORING_PRIORITY_QUEUE_HPP_

rclcpp/include/rclcpp/executors.hpp

@@ -66,12 +66,12 @@ using rclcpp::executors::SingleThreadedExecutor;
  *   If the time spent inside the blocking loop exceeds this timeout, return a `TIMEOUT` return code.
  * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
  */
-template<typename ResponseT, typename TimeRepT = int64_t, typename TimeT = std::milli>
+template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
 rclcpp::FutureReturnCode
 spin_node_until_future_complete(
   rclcpp::Executor & executor,
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
-  const std::shared_future<ResponseT> & future,
+  const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
   // TODO(wjwwood): does not work recursively; can't call spin_node_until_future_complete
@@ -82,13 +82,13 @@ spin_node_until_future_complete(
   return retcode;
 }
 
-template<typename NodeT = rclcpp::Node, typename ResponseT, typename TimeRepT = int64_t,
+template<typename NodeT = rclcpp::Node, typename FutureT, typename TimeRepT = int64_t,
   typename TimeT = std::milli>
 rclcpp::FutureReturnCode
 spin_node_until_future_complete(
   rclcpp::Executor & executor,
   std::shared_ptr<NodeT> node_ptr,
-  const std::shared_future<ResponseT> & future,
+  const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
   return rclcpp::executors::spin_node_until_future_complete(
@@ -104,10 +104,12 @@ template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::mi
 rclcpp::FutureReturnCode
 spin_until_future_complete(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
-  const std::shared_future<FutureT> & future,
+  const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
-  rclcpp::executors::SingleThreadedExecutor executor;
+  rclcpp::ExecutorOptions options;
+  options.context = node_ptr->get_context();
+  rclcpp::executors::SingleThreadedExecutor executor(options);
   return executors::spin_node_until_future_complete<FutureT>(executor, node_ptr, future, timeout);
 }
 
@@ -116,7 +118,7 @@ template<typename NodeT = rclcpp::Node, typename FutureT, typename TimeRepT = in
 rclcpp::FutureReturnCode
 spin_until_future_complete(
   std::shared_ptr<NodeT> node_ptr,
-  const std::shared_future<FutureT> & future,
+  const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
   return rclcpp::spin_until_future_complete(node_ptr->get_node_base_interface(), future, timeout);

rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp

@@ -49,9 +49,10 @@ public:
    * \param number_of_threads number of threads to have in the thread pool,
    *   the default 0 will use the number of cpu cores found instead
    * \param yield_before_execute if true std::this_thread::yield() is called
+   * \param timeout maximum time to wait
    */
   RCLCPP_PUBLIC
-  MultiThreadedExecutor(
+  explicit MultiThreadedExecutor(
     const rclcpp::ExecutorOptions & options = rclcpp::ExecutorOptions(),
     size_t number_of_threads = 0,
     bool yield_before_execute = false,
@@ -60,6 +61,10 @@ public:
   RCLCPP_PUBLIC
   virtual ~MultiThreadedExecutor();
 
+  /**
+   * \sa rclcpp::Executor:spin() for more details
+   * \throws std::runtime_error when spin() called while already spinning
+   */
   RCLCPP_PUBLIC
   void
   spin() override;
@@ -80,8 +85,6 @@ private:
   size_t number_of_threads_;
   bool yield_before_execute_;
   std::chrono::nanoseconds next_exec_timeout_;
-
-  std::set<TimerBase::SharedPtr> scheduled_timers_;
 };
 
 }  // namespace executors

rclcpp/include/rclcpp/executors/single_threaded_executor.hpp

@@ -59,6 +59,7 @@ public:
    * the process until canceled.
    * It may be interrupt by a call to rclcpp::Executor::cancel() or by ctrl-c
    * if the associated context is configured to shutdown on SIGINT.
+   * \throws std::runtime_error when spin() called while already spinning
    */
   RCLCPP_PUBLIC
   void

rclcpp/include/rclcpp/executors/static_executor_entities_collector.hpp

@@ -17,7 +17,9 @@
 
 #include <chrono>
 #include <list>
+#include <map>
 #include <memory>
+#include <vector>
 
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
@@ -32,6 +34,9 @@ namespace rclcpp
 {
 namespace executors
 {
+typedef std::map<rclcpp::CallbackGroup::WeakPtr,
+    rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
+    std::owner_less<rclcpp::CallbackGroup::WeakPtr>> WeakCallbackGroupsToNodesMap;
 
 class StaticExecutorEntitiesCollector final
   : public rclcpp::Waitable,
@@ -45,56 +50,144 @@ public:
   StaticExecutorEntitiesCollector() = default;
 
   // Destructor
+  RCLCPP_PUBLIC
   ~StaticExecutorEntitiesCollector();
 
+  /// Initialize StaticExecutorEntitiesCollector
+  /**
+   * \param p_wait_set A reference to the wait set to be used in the executor
+   * \param memory_strategy Shared pointer to the memory strategy to set.
+   * \throws std::runtime_error if memory strategy is null
+   */
   RCLCPP_PUBLIC
   void
   init(
     rcl_wait_set_t * p_wait_set,
-    rclcpp::memory_strategy::MemoryStrategy::SharedPtr & memory_strategy,
-    rcl_guard_condition_t * executor_guard_condition);
+    rclcpp::memory_strategy::MemoryStrategy::SharedPtr memory_strategy);
+
+  /// Finalize StaticExecutorEntitiesCollector to clear resources
+  RCLCPP_PUBLIC
+  bool
+  is_init() {return initialized_;}
 
   RCLCPP_PUBLIC
   void
-  execute() override;
+  fini();
 
+  /// Execute the waitable.
   RCLCPP_PUBLIC
   void
-  fill_memory_strategy();
+  execute(std::shared_ptr<void> & data) override;
 
+  /// Take the data so that it can be consumed with `execute`.
+  /**
+   * For `StaticExecutorEntitiesCollector`, this always return `nullptr`.
+   * \sa rclcpp::Waitable::take_data()
+   */
   RCLCPP_PUBLIC
-  void
-  fill_executable_list();
-
-  /// Function to reallocate space for entities in the wait set.
-  RCLCPP_PUBLIC
-  void
-  prepare_wait_set();
+  std::shared_ptr<void>
+  take_data() override;
 
   /// Function to add_handles_to_wait_set and wait for work and
-  // block until the wait set is ready or until the timeout has been exceeded.
+  /**
+   * block until the wait set is ready or until the timeout has been exceeded.
+   * \throws std::runtime_error if wait set couldn't be cleared or filled.
+   * \throws any rcl errors from rcl_wait, \see rclcpp::exceptions::throw_from_rcl_error()
+   */
   RCLCPP_PUBLIC
   void
   refresh_wait_set(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1));
 
+  /**
+   * \throws std::runtime_error if it couldn't add guard condition to wait set
+   */
   RCLCPP_PUBLIC
-  bool
+  void
   add_to_wait_set(rcl_wait_set_t * wait_set) override;
 
   RCLCPP_PUBLIC
   size_t
   get_number_of_ready_guard_conditions() override;
 
+  /// Add a callback group to an executor.
+  /**
+   * \see rclcpp::Executor::add_callback_group
+   */
   RCLCPP_PUBLIC
-  void
+  bool
+  add_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr);
+
+  /// Add a callback group to an executor.
+  /**
+   * \see rclcpp::Executor::add_callback_group
+   * \return boolean whether the node from the callback group is new
+   */
+  RCLCPP_PUBLIC
+  bool
+  add_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
+
+  /// Remove a callback group from the executor.
+  /**
+   * \see rclcpp::Executor::remove_callback_group
+   */
+  RCLCPP_PUBLIC
+  bool
+  remove_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr);
+
+  /// Remove a callback group from the executor.
+  /**
+   * \see rclcpp::Executor::remove_callback_group_from_map
+   */
+  RCLCPP_PUBLIC
+  bool
+  remove_callback_group_from_map(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
+
+  /**
+   * \see rclcpp::Executor::add_node()
+   * \throw std::runtime_error if node was already added
+   */
+  RCLCPP_PUBLIC
+  bool
   add_node(
     rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr);
 
+  /**
+   * \see rclcpp::Executor::remove_node()
+   * \throw std::runtime_error if no guard condition is associated with node.
+   */
   RCLCPP_PUBLIC
   bool
   remove_node(
     rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr);
 
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_all_callback_groups();
+
+  /// Get callback groups that belong to executor.
+  /**
+   * \see rclcpp::Executor::get_manually_added_callback_groups()
+   */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_manually_added_callback_groups();
+
+  /// Get callback groups that belong to executor.
+  /**
+   * \see rclcpp::Executor::get_automatically_added_callback_groups_from_nodes()
+   */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_automatically_added_callback_groups_from_nodes();
+
   /// Complete all available queued work without blocking.
   /**
    * This function checks if after the guard condition was triggered
@@ -105,61 +198,157 @@ public:
   bool
   is_ready(rcl_wait_set_t * wait_set) override;
 
+  /// Return number of timers
+  /**
+   * \return number of timers
+   */
   RCLCPP_PUBLIC
   size_t
   get_number_of_timers() {return exec_list_.number_of_timers;}
 
+  /// Return number of subscriptions
+  /**
+   * \return number of subscriptions
+   */
   RCLCPP_PUBLIC
   size_t
   get_number_of_subscriptions() {return exec_list_.number_of_subscriptions;}
 
+  /// Return number of services
+  /**
+   * \return number of services
+   */
   RCLCPP_PUBLIC
   size_t
   get_number_of_services() {return exec_list_.number_of_services;}
 
+  /// Return number of clients
+  /**
+   * \return number of clients
+   */
   RCLCPP_PUBLIC
   size_t
   get_number_of_clients() {return exec_list_.number_of_clients;}
 
+  /// Return number of waitables
+  /**
+   * \return number of waitables
+   */
   RCLCPP_PUBLIC
   size_t
   get_number_of_waitables() {return exec_list_.number_of_waitables;}
 
+  /** Return a SubscritionBase Sharedptr by index.
+   * \param[in] i The index of the SubscritionBase
+   * \return a SubscritionBase shared pointer
+   * \throws std::out_of_range if the argument is higher than the size of the structrue.
+   */
   RCLCPP_PUBLIC
   rclcpp::SubscriptionBase::SharedPtr
   get_subscription(size_t i) {return exec_list_.subscription[i];}
 
+  /** Return a TimerBase Sharedptr by index.
+   * \param[in] i The index of the TimerBase
+   * \return a TimerBase shared pointer
+   * \throws std::out_of_range if the argument is higher than the size.
+   */
   RCLCPP_PUBLIC
   rclcpp::TimerBase::SharedPtr
   get_timer(size_t i) {return exec_list_.timer[i];}
 
+  /** Return a ServiceBase Sharedptr by index.
+   * \param[in] i The index of the ServiceBase
+   * \return a ServiceBase shared pointer
+   * \throws std::out_of_range if the argument is higher than the size.
+   */
   RCLCPP_PUBLIC
   rclcpp::ServiceBase::SharedPtr
   get_service(size_t i) {return exec_list_.service[i];}
 
+  /** Return a ClientBase Sharedptr by index
+   * \param[in] i The index of the ClientBase
+   * \return a ClientBase shared pointer
+   * \throws std::out_of_range if the argument is higher than the size.
+   */
   RCLCPP_PUBLIC
   rclcpp::ClientBase::SharedPtr
   get_client(size_t i) {return exec_list_.client[i];}
 
+  /** Return a Waitable Sharedptr by index
+   * \param[in] i The index of the Waitable
+   * \return a Waitable shared pointer
+   * \throws std::out_of_range if the argument is higher than the size.
+   */
   RCLCPP_PUBLIC
   rclcpp::Waitable::SharedPtr
   get_waitable(size_t i) {return exec_list_.waitable[i];}
 
 private:
-  /// Nodes guard conditions which trigger this waitable
-  std::list<const rcl_guard_condition_t *> guard_conditions_;
+  /// Function to reallocate space for entities in the wait set.
+  /**
+   * \throws std::runtime_error if wait set couldn't be cleared or resized.
+   */
+  void
+  prepare_wait_set();
+
+  void
+  fill_executable_list();
+
+  void
+  fill_memory_strategy();
+
+  /// Return true if the node belongs to the collector
+  /**
+   * \param[in] node_ptr a node base interface shared pointer
+   * \param[in] weak_groups_to_nodes map to nodes to lookup
+   * \return boolean whether a node belongs the collector
+   */
+  bool
+  has_node(
+    const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) const;
+
+  /// Add all callback groups that can be automatically added by any executor
+  /// and is not already associated with an executor from nodes
+  /// that are associated with executor
+  /**
+   * \see rclcpp::Executor::add_callback_groups_from_nodes_associated_to_executor()
+   */
+  void
+  add_callback_groups_from_nodes_associated_to_executor();
+
+  void
+  fill_executable_list_from_map(const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   /// Memory strategy: an interface for handling user-defined memory allocation strategies.
   rclcpp::memory_strategy::MemoryStrategy::SharedPtr memory_strategy_;
 
+  // maps callback groups to nodes.
+  WeakCallbackGroupsToNodesMap weak_groups_associated_with_executor_to_nodes_;
+  // maps callback groups to nodes.
+  WeakCallbackGroupsToNodesMap weak_groups_to_nodes_associated_with_executor_;
+
+  typedef std::map<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
+      const rclcpp::GuardCondition *,
+      std::owner_less<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr>>
+    WeakNodesToGuardConditionsMap;
+  WeakNodesToGuardConditionsMap weak_nodes_to_guard_conditions_;
+
   /// List of weak nodes registered in the static executor
   std::list<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr> weak_nodes_;
 
+  // Mutex to protect vector of new nodes.
+  std::mutex new_nodes_mutex_;
+  std::vector<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr> new_nodes_;
+
   /// Wait set for managing entities that the rmw layer waits on.
   rcl_wait_set_t * p_wait_set_ = nullptr;
 
   /// Executable list: timers, subscribers, clients, services and waitables
   rclcpp::experimental::ExecutableList exec_list_;
+
+  /// Bool to check if the entities collector has been initialized
+  bool initialized_ = false;
 };
 
 }  // namespace executors

rclcpp/include/rclcpp/executors/static_single_threaded_executor.hpp

@@ -15,6 +15,7 @@
 #ifndef RCLCPP__EXECUTORS__STATIC_SINGLE_THREADED_EXECUTOR_HPP_
 #define RCLCPP__EXECUTORS__STATIC_SINGLE_THREADED_EXECUTOR_HPP_
 
+#include <chrono>
 #include <cassert>
 #include <cstdlib>
 #include <memory>
@@ -69,19 +70,76 @@ public:
   virtual ~StaticSingleThreadedExecutor();
 
   /// Static executor implementation of spin.
-  // This function will block until work comes in, execute it, and keep blocking.
-  // It will only be interrupt by a CTRL-C (managed by the global signal handler).
+  /**
+   * This function will block until work comes in, execute it, and keep blocking.
+   * It will only be interrupted by a CTRL-C (managed by the global signal handler).
+   * \throws std::runtime_error when spin() called while already spinning
+   */
   RCLCPP_PUBLIC
   void
   spin() override;
 
+  /// Static executor implementation of spin some
+  /**
+   * This non-blocking function will execute entities that
+   * were ready when this API was called, until timeout or no
+   * more work available. Entities that got ready while
+   * executing work, won't be taken into account here.
+   *
+   * Example:
+   *   while(condition) {
+   *     spin_some();
+   *     sleep(); // User should have some sync work or
+   *              // sleep to avoid a 100% CPU usage
+   *   }
+   */
+  RCLCPP_PUBLIC
+  void
+  spin_some(std::chrono::nanoseconds max_duration = std::chrono::nanoseconds(0)) override;
+
+  /// Static executor implementation of spin all
+  /**
+   * This non-blocking function will execute entities until timeout (must be >= 0)
+   * or no more work available.
+   * If timeout is `0`, potentially it blocks forever until no more work is available.
+   * If new entities get ready while executing work available, they will be executed
+   * as long as the timeout hasn't expired.
+   *
+   * Example:
+   *   while(condition) {
+   *     spin_all();
+   *     sleep(); // User should have some sync work or
+   *              // sleep to avoid a 100% CPU usage
+   *   }
+   */
+  RCLCPP_PUBLIC
+  void
+  spin_all(std::chrono::nanoseconds max_duration) override;
+
+  /// Add a callback group to an executor.
+  /**
+   * \sa rclcpp::Executor::add_callback_group
+   */
+  RCLCPP_PUBLIC
+  void
+  add_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+    bool notify = true) override;
+
+  /// Remove callback group from the executor
+  /**
+   * \sa rclcpp::Executor::remove_callback_group
+   */
+  RCLCPP_PUBLIC
+  void
+  remove_callback_group(
+    rclcpp::CallbackGroup::SharedPtr group_ptr,
+    bool notify = true) override;
+
   /// Add a node to the executor.
   /**
-   * An executor can have zero or more nodes which provide work during `spin` functions.
-   * \param[in] node_ptr Shared pointer to the node to be added.
-   * \param[in] notify True to trigger the interrupt guard condition during this function. If
-   * the executor is blocked at the rmw layer while waiting for work and it is notified that a new
-   * node was added, it will wake up.
+   * \sa rclcpp::Executor::add_node
    */
   RCLCPP_PUBLIC
   void
@@ -90,16 +148,16 @@ public:
     bool notify = true) override;
 
   /// Convenience function which takes Node and forwards NodeBaseInterface.
+  /**
+   * \sa rclcpp::StaticSingleThreadedExecutor::add_node
+   */
   RCLCPP_PUBLIC
   void
   add_node(std::shared_ptr<rclcpp::Node> node_ptr, bool notify = true) override;
 
   /// Remove a node from the executor.
   /**
-   * \param[in] node_ptr Shared pointer to the node to remove.
-   * \param[in] notify True to trigger the interrupt guard condition and wake up the executor.
-   * This is useful if the last node was removed from the executor while the executor was blocked
-   * waiting for work in another thread, because otherwise the executor would never be notified.
+   * \sa rclcpp::Executor::remove_node
    */
   RCLCPP_PUBLIC
   void
@@ -108,85 +166,50 @@ public:
     bool notify = true) override;
 
   /// Convenience function which takes Node and forwards NodeBaseInterface.
+  /**
+   * \sa rclcpp::Executor::remove_node
+   */
   RCLCPP_PUBLIC
   void
   remove_node(std::shared_ptr<rclcpp::Node> node_ptr, bool notify = true) override;
 
-  /// Spin (blocking) until the future is complete, it times out waiting, or rclcpp is interrupted.
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_all_callback_groups() override;
+
+  /// Get callback groups that belong to executor.
   /**
-   * \param[in] future The future to wait on. If this function returns SUCCESS, the future can be
-   *   accessed without blocking (though it may still throw an exception).
-   * \param[in] timeout Optional timeout parameter, which gets passed to
-   *    Executor::execute_ready_executables.
-   *   `-1` is block forever, `0` is non-blocking.
-   *   If the time spent inside the blocking loop exceeds this timeout, return a TIMEOUT return
-   *   code.
-   * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
-   *
-   *  Example usage:
-   *  rclcpp::executors::StaticSingleThreadedExecutor exec;
-   *  // ... other part of code like creating node
-   *  // define future
-   *  exec.add_node(node);
-   *  exec.spin_until_future_complete(future);
-   */
-  template<typename ResponseT, typename TimeRepT = int64_t, typename TimeT = std::milli>
-  rclcpp::FutureReturnCode
-  spin_until_future_complete(
-    std::shared_future<ResponseT> & future,
-    std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
-  {
-    std::future_status status = future.wait_for(std::chrono::seconds(0));
-    if (status == std::future_status::ready) {
-      return rclcpp::FutureReturnCode::SUCCESS;
-    }
-
-    auto end_time = std::chrono::steady_clock::now();
-    std::chrono::nanoseconds timeout_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(
-      timeout);
-    if (timeout_ns > std::chrono::nanoseconds::zero()) {
-      end_time += timeout_ns;
-    }
-    std::chrono::nanoseconds timeout_left = timeout_ns;
-
-    entities_collector_ = std::make_shared<StaticExecutorEntitiesCollector>();
-    entities_collector_->init(&wait_set_, memory_strategy_, &interrupt_guard_condition_);
-
-    while (rclcpp::ok(this->context_)) {
-      // Do one set of work.
-      entities_collector_->refresh_wait_set(timeout_left);
-      execute_ready_executables();
-      // Check if the future is set, return SUCCESS if it is.
-      status = future.wait_for(std::chrono::seconds(0));
-      if (status == std::future_status::ready) {
-        return rclcpp::FutureReturnCode::SUCCESS;
-      }
-      // If the original timeout is < 0, then this is blocking, never TIMEOUT.
-      if (timeout_ns < std::chrono::nanoseconds::zero()) {
-        continue;
-      }
-      // Otherwise check if we still have time to wait, return TIMEOUT if not.
-      auto now = std::chrono::steady_clock::now();
-      if (now >= end_time) {
-        return rclcpp::FutureReturnCode::TIMEOUT;
-      }
-      // Subtract the elapsed time from the original timeout.
-      timeout_left = std::chrono::duration_cast<std::chrono::nanoseconds>(end_time - now);
-    }
-
-    // The future did not complete before ok() returned false, return INTERRUPTED.
-    return rclcpp::FutureReturnCode::INTERRUPTED;
-  }
-
-protected:
-  /// Check which executables in ExecutableList struct are ready from wait_set and execute them.
-  /**
-   * \param[in] exec_list Structure that can hold subscriptionbases, timerbases, etc
-   * \param[in] timeout Optional timeout parameter.
+   * \sa rclcpp::Executor::get_manually_added_callback_groups()
    */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_manually_added_callback_groups() override;
+
+  /// Get callback groups that belong to executor.
+  /**
+   * \sa rclcpp::Executor::get_automatically_added_callback_groups_from_nodes()
+   */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::CallbackGroup::WeakPtr>
+  get_automatically_added_callback_groups_from_nodes() override;
+
+protected:
+  /**
+   * @brief Executes ready executables from wait set.
+   * @param spin_once if true executes only the first ready executable.
+   * @return true if any executable was ready.
+   */
+  RCLCPP_PUBLIC
+  bool
+  execute_ready_executables(bool spin_once = false);
+
   RCLCPP_PUBLIC
   void
-  execute_ready_executables();
+  spin_some_impl(std::chrono::nanoseconds max_duration, bool exhaustive);
+
+  RCLCPP_PUBLIC
+  void
+  spin_once_impl(std::chrono::nanoseconds timeout) override;
 
 private:
   RCLCPP_DISABLE_COPY(StaticSingleThreadedExecutor)

rclcpp/include/rclcpp/expand_topic_or_service_name.hpp

@@ -49,6 +49,8 @@ namespace rclcpp
  * \throws InvalidServiceNameError if name is invalid and is_service is true
  * \throws std::bad_alloc if memory cannot be allocated
  * \throws RCLError if an unexpect error occurs
+ * \throws std::runtime_error if the topic name is unexpectedly valid or,
+ *    if the rcl name is invalid or if the rcl namespace is invalid
  */
 RCLCPP_PUBLIC
 std::string

rclcpp/include/rclcpp/experimental/buffers/intra_process_buffer.hpp

@@ -16,6 +16,7 @@
 #define RCLCPP__EXPERIMENTAL__BUFFERS__INTRA_PROCESS_BUFFER_HPP_
 
 #include <memory>
+#include <stdexcept>
 #include <type_traits>
 #include <utility>
 

rclcpp/include/rclcpp/experimental/buffers/ring_buffer_implementation.hpp

@@ -15,10 +15,6 @@
 #ifndef RCLCPP__EXPERIMENTAL__BUFFERS__RING_BUFFER_IMPLEMENTATION_HPP_
 #define RCLCPP__EXPERIMENTAL__BUFFERS__RING_BUFFER_IMPLEMENTATION_HPP_
 
-#include <algorithm>
-#include <cstddef>
-#include <cstdint>
-#include <memory>
 #include <mutex>
 #include <stdexcept>
 #include <utility>
@@ -37,6 +33,10 @@ namespace experimental
 namespace buffers
 {
 
+/// Store elements in a fixed-size, FIFO buffer
+/**
+ * All public member functions are thread-safe.
+ */
 template<typename BufferT>
 class RingBufferImplementation : public BufferImplementationBase<BufferT>
 {
@@ -55,55 +55,124 @@ public:
 
   virtual ~RingBufferImplementation() {}
 
+  /// Add a new element to store in the ring buffer
+  /**
+   * This member function is thread-safe.
+   *
+   * \param request the element to be stored in the ring buffer
+   */
   void enqueue(BufferT request)
   {
     std::lock_guard<std::mutex> lock(mutex_);
 
-    write_index_ = next(write_index_);
+    write_index_ = next_(write_index_);
     ring_buffer_[write_index_] = std::move(request);
 
-    if (is_full()) {
-      read_index_ = next(read_index_);
+    if (is_full_()) {
+      read_index_ = next_(read_index_);
     } else {
       size_++;
     }
   }
 
+  /// Remove the oldest element from ring buffer
+  /**
+   * This member function is thread-safe.
+   *
+   * \return the element that is being removed from the ring buffer
+   */
   BufferT dequeue()
   {
     std::lock_guard<std::mutex> lock(mutex_);
 
-    if (!has_data()) {
-      RCLCPP_ERROR(rclcpp::get_logger("rclcpp"), "Calling dequeue on empty intra-process buffer");
-      throw std::runtime_error("Calling dequeue on empty intra-process buffer");
+    if (!has_data_()) {
+      return BufferT();
     }
 
     auto request = std::move(ring_buffer_[read_index_]);
-    read_index_ = next(read_index_);
+    read_index_ = next_(read_index_);
 
     size_--;
 
     return request;
   }
 
+  /// Get the next index value for the ring buffer
+  /**
+   * This member function is thread-safe.
+   *
+   * \param val the current index value
+   * \return the next index value
+   */
   inline size_t next(size_t val)
   {
-    return (val + 1) % capacity_;
+    std::lock_guard<std::mutex> lock(mutex_);
+    return next_(val);
   }
 
+  /// Get if the ring buffer has at least one element stored
+  /**
+   * This member function is thread-safe.
+   *
+   * \return `true` if there is data and `false` otherwise
+   */
   inline bool has_data() const
   {
-    return size_ != 0;
+    std::lock_guard<std::mutex> lock(mutex_);
+    return has_data_();
   }
 
-  inline bool is_full()
+  /// Get if the size of the buffer is equal to its capacity
+  /**
+   * This member function is thread-safe.
+   *
+   * \return `true` if the size of the buffer is equal is capacity
+   * and `false` otherwise
+   */
+  inline bool is_full() const
   {
-    return size_ == capacity_;
+    std::lock_guard<std::mutex> lock(mutex_);
+    return is_full_();
   }
 
   void clear() {}
 
 private:
+  /// Get the next index value for the ring buffer
+  /**
+   * This member function is not thread-safe.
+   *
+   * \param val the current index value
+   * \return the next index value
+   */
+  inline size_t next_(size_t val)
+  {
+    return (val + 1) % capacity_;
+  }
+
+  /// Get if the ring buffer has at least one element stored
+  /**
+   * This member function is not thread-safe.
+   *
+   * \return `true` if there is data and `false` otherwise
+   */
+  inline bool has_data_() const
+  {
+    return size_ != 0;
+  }
+
+  /// Get if the size of the buffer is equal to its capacity
+  /**
+   * This member function is not thread-safe.
+   *
+   * \return `true` if the size of the buffer is equal is capacity
+   * and `false` otherwise
+   */
+  inline bool is_full_() const
+  {
+    return size_ == capacity_;
+  }
+
   size_t capacity_;
 
   std::vector<BufferT> ring_buffer_;
@@ -112,7 +181,7 @@ private:
   size_t read_index_;
   size_t size_;
 
-  std::mutex mutex_;
+  mutable std::mutex mutex_;
 };
 
 }  // namespace buffers

rclcpp/include/rclcpp/experimental/create_intra_process_buffer.hpp

@@ -16,14 +16,13 @@
 #define RCLCPP__EXPERIMENTAL__CREATE_INTRA_PROCESS_BUFFER_HPP_
 
 #include <memory>
-#include <type_traits>
+#include <stdexcept>
 #include <utility>
 
-#include "rcl/subscription.h"
-
 #include "rclcpp/experimental/buffers/intra_process_buffer.hpp"
 #include "rclcpp/experimental/buffers/ring_buffer_implementation.hpp"
 #include "rclcpp/intra_process_buffer_type.hpp"
+#include "rclcpp/qos.hpp"
 
 namespace rclcpp
 {
@@ -37,13 +36,13 @@ template<
 typename rclcpp::experimental::buffers::IntraProcessBuffer<MessageT, Alloc, Deleter>::UniquePtr
 create_intra_process_buffer(
   IntraProcessBufferType buffer_type,
-  rmw_qos_profile_t qos,
+  const rclcpp::QoS & qos,
   std::shared_ptr<Alloc> allocator)
 {
   using MessageSharedPtr = std::shared_ptr<const MessageT>;
   using MessageUniquePtr = std::unique_ptr<MessageT, Deleter>;
 
-  size_t buffer_size = qos.depth;
+  size_t buffer_size = qos.depth();
 
   using rclcpp::experimental::buffers::IntraProcessBuffer;
   typename IntraProcessBuffer<MessageT, Alloc, Deleter>::UniquePtr buffer;

rclcpp/include/rclcpp/experimental/executable_list.hpp

@@ -15,7 +15,6 @@
 #ifndef RCLCPP__EXPERIMENTAL__EXECUTABLE_LIST_HPP_
 #define RCLCPP__EXPERIMENTAL__EXECUTABLE_LIST_HPP_
 
-#include <memory>
 #include <vector>
 
 #include "rclcpp/client.hpp"

rclcpp/include/rclcpp/experimental/intra_process_manager.hpp

@@ -19,24 +19,24 @@
 
 #include <shared_mutex>
 
-#include <algorithm>
-#include <atomic>
-#include <cstdint>
-#include <exception>
-#include <map>
+#include <iterator>
 #include <memory>
-#include <string>
+#include <stdexcept>
 #include <unordered_map>
 #include <utility>
 #include <vector>
+#include <typeinfo>
 
 #include "rclcpp/allocator/allocator_deleter.hpp"
+#include "rclcpp/experimental/ros_message_intra_process_buffer.hpp"
 #include "rclcpp/experimental/subscription_intra_process.hpp"
 #include "rclcpp/experimental/subscription_intra_process_base.hpp"
+#include "rclcpp/experimental/subscription_intra_process_buffer.hpp"
 #include "rclcpp/logger.hpp"
 #include "rclcpp/logging.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/publisher_base.hpp"
+#include "rclcpp/type_adapter.hpp"
 #include "rclcpp/visibility_control.hpp"
 
 namespace rclcpp
@@ -172,16 +172,19 @@ public:
    *
    * \param intra_process_publisher_id the id of the publisher of this message.
    * \param message the message that is being stored.
+   * \param allocator for allocations when buffering messages.
    */
   template<
     typename MessageT,
-    typename Alloc = std::allocator<void>,
-    typename Deleter = std::default_delete<MessageT>>
+    typename ROSMessageType,
+    typename Alloc,
+    typename Deleter = std::default_delete<MessageT>
+  >
   void
   do_intra_process_publish(
     uint64_t intra_process_publisher_id,
     std::unique_ptr<MessageT, Deleter> message,
-    std::shared_ptr<typename allocator::AllocRebind<MessageT, Alloc>::allocator_type> allocator)
+    typename allocator::AllocRebind<MessageT, Alloc>::allocator_type & allocator)
   {
     using MessageAllocTraits = allocator::AllocRebind<MessageT, Alloc>;
     using MessageAllocatorT = typename MessageAllocTraits::allocator_type;
@@ -202,12 +205,13 @@ public:
       // None of the buffers require ownership, so we promote the pointer
       std::shared_ptr<MessageT> msg = std::move(message);
 
-      this->template add_shared_msg_to_buffers<MessageT>(msg, sub_ids.take_shared_subscriptions);
+      this->template add_shared_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
+        msg, sub_ids.take_shared_subscriptions);
     } else if (!sub_ids.take_ownership_subscriptions.empty() && // NOLINT
       sub_ids.take_shared_subscriptions.size() <= 1)
     {
       // There is at maximum 1 buffer that does not require ownership.
-      // So we this case is equivalent to all the buffers requiring ownership
+      // So this case is equivalent to all the buffers requiring ownership
 
       // Merge the two vector of ids into a unique one
       std::vector<uint64_t> concatenated_vector(sub_ids.take_shared_subscriptions);
@@ -215,8 +219,7 @@ public:
         concatenated_vector.end(),
         sub_ids.take_ownership_subscriptions.begin(),
         sub_ids.take_ownership_subscriptions.end());
-
-      this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter>(
+      this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
         std::move(message),
         concatenated_vector,
         allocator);
@@ -225,24 +228,26 @@ public:
     {
       // Construct a new shared pointer from the message
       // for the buffers that do not require ownership
-      auto shared_msg = std::allocate_shared<MessageT, MessageAllocatorT>(*allocator, *message);
+      auto shared_msg = std::allocate_shared<MessageT, MessageAllocatorT>(allocator, *message);
 
-      this->template add_shared_msg_to_buffers<MessageT>(
+      this->template add_shared_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
         shared_msg, sub_ids.take_shared_subscriptions);
-      this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter>(
+      this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
         std::move(message), sub_ids.take_ownership_subscriptions, allocator);
     }
   }
 
   template<
     typename MessageT,
-    typename Alloc = std::allocator<void>,
-    typename Deleter = std::default_delete<MessageT>>
+    typename ROSMessageType,
+    typename Alloc,
+    typename Deleter = std::default_delete<MessageT>
+  >
   std::shared_ptr<const MessageT>
   do_intra_process_publish_and_return_shared(
     uint64_t intra_process_publisher_id,
     std::unique_ptr<MessageT, Deleter> message,
-    std::shared_ptr<typename allocator::AllocRebind<MessageT, Alloc>::allocator_type> allocator)
+    typename allocator::AllocRebind<MessageT, Alloc>::allocator_type & allocator)
   {
     using MessageAllocTraits = allocator::AllocRebind<MessageT, Alloc>;
     using MessageAllocatorT = typename MessageAllocTraits::allocator_type;
@@ -263,27 +268,26 @@ public:
       // If there are no owning, just convert to shared.
       std::shared_ptr<MessageT> shared_msg = std::move(message);
       if (!sub_ids.take_shared_subscriptions.empty()) {
-        this->template add_shared_msg_to_buffers<MessageT>(
+        this->template add_shared_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
           shared_msg, sub_ids.take_shared_subscriptions);
       }
       return shared_msg;
     } else {
       // Construct a new shared pointer from the message for the buffers that
       // do not require ownership and to return.
-      auto shared_msg = std::allocate_shared<MessageT, MessageAllocatorT>(*allocator, *message);
+      auto shared_msg = std::allocate_shared<MessageT, MessageAllocatorT>(allocator, *message);
 
       if (!sub_ids.take_shared_subscriptions.empty()) {
-        this->template add_shared_msg_to_buffers<MessageT>(
+        this->template add_shared_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
           shared_msg,
           sub_ids.take_shared_subscriptions);
       }
       if (!sub_ids.take_ownership_subscriptions.empty()) {
-        this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter>(
+        this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter, ROSMessageType>(
           std::move(message),
           sub_ids.take_ownership_subscriptions,
           allocator);
       }
-
       return shared_msg;
     }
   }
@@ -303,25 +307,6 @@ public:
   get_subscription_intra_process(uint64_t intra_process_subscription_id);
 
 private:
-  struct SubscriptionInfo
-  {
-    SubscriptionInfo() = default;
-
-    rclcpp::experimental::SubscriptionIntraProcessBase::SharedPtr subscription;
-    rmw_qos_profile_t qos;
-    const char * topic_name;
-    bool use_take_shared_method;
-  };
-
-  struct PublisherInfo
-  {
-    PublisherInfo() = default;
-
-    rclcpp::PublisherBase::WeakPtr publisher;
-    rmw_qos_profile_t qos;
-    const char * topic_name;
-  };
-
   struct SplittedSubscriptions
   {
     std::vector<uint64_t> take_shared_subscriptions;
@@ -329,10 +314,10 @@ private:
   };
 
   using SubscriptionMap =
-    std::unordered_map<uint64_t, SubscriptionInfo>;
+    std::unordered_map<uint64_t, rclcpp::experimental::SubscriptionIntraProcessBase::WeakPtr>;
 
   using PublisherMap =
-    std::unordered_map<uint64_t, PublisherInfo>;
+    std::unordered_map<uint64_t, rclcpp::PublisherBase::WeakPtr>;
 
   using PublisherToSubscriptionIdsMap =
     std::unordered_map<uint64_t, SplittedSubscriptions>;
@@ -348,65 +333,181 @@ private:
 
   RCLCPP_PUBLIC
   bool
-  can_communicate(PublisherInfo pub_info, SubscriptionInfo sub_info) const;
+  can_communicate(
+    rclcpp::PublisherBase::SharedPtr pub,
+    rclcpp::experimental::SubscriptionIntraProcessBase::SharedPtr sub) const;
 
-  template<typename MessageT>
+  template<
+    typename MessageT,
+    typename Alloc,
+    typename Deleter,
+    typename ROSMessageType>
   void
   add_shared_msg_to_buffers(
     std::shared_ptr<const MessageT> message,
     std::vector<uint64_t> subscription_ids)
   {
+    using ROSMessageTypeAllocatorTraits = allocator::AllocRebind<ROSMessageType, Alloc>;
+    using ROSMessageTypeAllocator = typename ROSMessageTypeAllocatorTraits::allocator_type;
+    using ROSMessageTypeDeleter = allocator::Deleter<ROSMessageTypeAllocator, ROSMessageType>;
+
+    using PublishedType = typename rclcpp::TypeAdapter<MessageT>::custom_type;
+    using PublishedTypeAllocatorTraits = allocator::AllocRebind<PublishedType, Alloc>;
+    using PublishedTypeAllocator = typename PublishedTypeAllocatorTraits::allocator_type;
+    using PublishedTypeDeleter = allocator::Deleter<PublishedTypeAllocator, PublishedType>;
+
     for (auto id : subscription_ids) {
       auto subscription_it = subscriptions_.find(id);
       if (subscription_it == subscriptions_.end()) {
         throw std::runtime_error("subscription has unexpectedly gone out of scope");
       }
-      auto subscription_base = subscription_it->second.subscription;
+      auto subscription_base = subscription_it->second.lock();
+      if (subscription_base == nullptr) {
+        subscriptions_.erase(id);
+        continue;
+      }
 
-      auto subscription = std::static_pointer_cast<
-        rclcpp::experimental::SubscriptionIntraProcess<MessageT>
+      auto subscription = std::dynamic_pointer_cast<
+        rclcpp::experimental::SubscriptionIntraProcessBuffer<PublishedType,
+        PublishedTypeAllocator, PublishedTypeDeleter, ROSMessageType>
         >(subscription_base);
+      if (subscription != nullptr) {
+        subscription->provide_intra_process_data(message);
+        continue;
+      }
 
-      subscription->provide_intra_process_message(message);
+      auto ros_message_subscription = std::dynamic_pointer_cast<
+        rclcpp::experimental::SubscriptionROSMsgIntraProcessBuffer<ROSMessageType,
+        ROSMessageTypeAllocator, ROSMessageTypeDeleter>
+        >(subscription_base);
+      if (nullptr == ros_message_subscription) {
+        throw std::runtime_error(
+                "failed to dynamic cast SubscriptionIntraProcessBase to "
+                "SubscriptionIntraProcessBuffer<MessageT, Alloc, Deleter>, or to "
+                "SubscriptionROSMsgIntraProcessBuffer<ROSMessageType,ROSMessageTypeAllocator,"
+                "ROSMessageTypeDeleter> which can happen when the publisher and "
+                "subscription use different allocator types, which is not supported");
+      }
+
+      if constexpr (rclcpp::TypeAdapter<MessageT>::is_specialized::value) {
+        ROSMessageType ros_msg;
+        rclcpp::TypeAdapter<MessageT>::convert_to_ros_message(*message, ros_msg);
+        ros_message_subscription->provide_intra_process_message(
+          std::make_shared<ROSMessageType>(ros_msg));
+      } else {
+        if constexpr (std::is_same<MessageT, ROSMessageType>::value) {
+          ros_message_subscription->provide_intra_process_message(message);
+        } else {
+          if constexpr (std::is_same<typename rclcpp::TypeAdapter<MessageT,
+            ROSMessageType>::ros_message_type, ROSMessageType>::value)
+          {
+            ROSMessageType ros_msg;
+            rclcpp::TypeAdapter<MessageT, ROSMessageType>::convert_to_ros_message(
+              *message, ros_msg);
+            ros_message_subscription->provide_intra_process_message(
+              std::make_shared<ROSMessageType>(ros_msg));
+          }
+        }
+      }
     }
   }
 
   template<
     typename MessageT,
-    typename Alloc = std::allocator<void>,
-    typename Deleter = std::default_delete<MessageT>>
+    typename Alloc,
+    typename Deleter,
+    typename ROSMessageType>
   void
   add_owned_msg_to_buffers(
     std::unique_ptr<MessageT, Deleter> message,
     std::vector<uint64_t> subscription_ids,
-    std::shared_ptr<typename allocator::AllocRebind<MessageT, Alloc>::allocator_type> allocator)
+    typename allocator::AllocRebind<MessageT, Alloc>::allocator_type & allocator)
   {
     using MessageAllocTraits = allocator::AllocRebind<MessageT, Alloc>;
     using MessageUniquePtr = std::unique_ptr<MessageT, Deleter>;
 
+    using ROSMessageTypeAllocatorTraits = allocator::AllocRebind<ROSMessageType, Alloc>;
+    using ROSMessageTypeAllocator = typename ROSMessageTypeAllocatorTraits::allocator_type;
+    using ROSMessageTypeDeleter = allocator::Deleter<ROSMessageTypeAllocator, ROSMessageType>;
+
+    using PublishedType = typename rclcpp::TypeAdapter<MessageT>::custom_type;
+    using PublishedTypeAllocatorTraits = allocator::AllocRebind<PublishedType, Alloc>;
+    using PublishedTypeAllocator = typename PublishedTypeAllocatorTraits::allocator_type;
+    using PublishedTypeDeleter = allocator::Deleter<PublishedTypeAllocator, PublishedType>;
+
     for (auto it = subscription_ids.begin(); it != subscription_ids.end(); it++) {
       auto subscription_it = subscriptions_.find(*it);
       if (subscription_it == subscriptions_.end()) {
         throw std::runtime_error("subscription has unexpectedly gone out of scope");
       }
-      auto subscription_base = subscription_it->second.subscription;
+      auto subscription_base = subscription_it->second.lock();
+      if (subscription_base == nullptr) {
+        subscriptions_.erase(subscription_it);
+        continue;
+      }
 
-      auto subscription = std::static_pointer_cast<
-        rclcpp::experimental::SubscriptionIntraProcess<MessageT>
+      auto subscription = std::dynamic_pointer_cast<
+        rclcpp::experimental::SubscriptionIntraProcessBuffer<PublishedType,
+        PublishedTypeAllocator, PublishedTypeDeleter, ROSMessageType>
         >(subscription_base);
+      if (subscription != nullptr) {
+        if (std::next(it) == subscription_ids.end()) {
+          // If this is the last subscription, give up ownership
+          subscription->provide_intra_process_data(std::move(message));
+          // Last message delivered, break from for loop
+          break;
+        } else {
+          // Copy the message since we have additional subscriptions to serve
+          Deleter deleter = message.get_deleter();
+          auto ptr = MessageAllocTraits::allocate(allocator, 1);
+          MessageAllocTraits::construct(allocator, ptr, *message);
 
-      if (std::next(it) == subscription_ids.end()) {
-        // If this is the last subscription, give up ownership
-        subscription->provide_intra_process_message(std::move(message));
+          subscription->provide_intra_process_data(std::move(MessageUniquePtr(ptr, deleter)));
+        }
+
+        continue;
+      }
+
+      auto ros_message_subscription = std::dynamic_pointer_cast<
+        rclcpp::experimental::SubscriptionROSMsgIntraProcessBuffer<ROSMessageType,
+        ROSMessageTypeAllocator, ROSMessageTypeDeleter>
+        >(subscription_base);
+      if (nullptr == ros_message_subscription) {
+        throw std::runtime_error(
+                "failed to dynamic cast SubscriptionIntraProcessBase to "
+                "SubscriptionIntraProcessBuffer<MessageT, Alloc, Deleter>, or to "
+                "SubscriptionROSMsgIntraProcessBuffer<ROSMessageType,ROSMessageTypeAllocator,"
+                "ROSMessageTypeDeleter> which can happen when the publisher and "
+                "subscription use different allocator types, which is not supported");
+      }
+
+      if constexpr (rclcpp::TypeAdapter<MessageT, ROSMessageType>::is_specialized::value) {
+        ROSMessageTypeAllocator ros_message_alloc(allocator);
+        auto ptr = ROSMessageTypeAllocatorTraits::allocate(ros_message_alloc, 1);
+        ROSMessageTypeAllocatorTraits::construct(ros_message_alloc, ptr);
+        ROSMessageTypeDeleter deleter;
+        allocator::set_allocator_for_deleter(&deleter, &allocator);
+        rclcpp::TypeAdapter<MessageT, ROSMessageType>::convert_to_ros_message(*message, *ptr);
+        auto ros_msg = std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>(ptr, deleter);
+        ros_message_subscription->provide_intra_process_message(std::move(ros_msg));
       } else {
-        // Copy the message since we have additional subscriptions to serve
-        MessageUniquePtr copy_message;
-        Deleter deleter = message.get_deleter();
-        auto ptr = MessageAllocTraits::allocate(*allocator.get(), 1);
-        MessageAllocTraits::construct(*allocator.get(), ptr, *message);
-        copy_message = MessageUniquePtr(ptr, deleter);
+        if constexpr (std::is_same<MessageT, ROSMessageType>::value) {
+          if (std::next(it) == subscription_ids.end()) {
+            // If this is the last subscription, give up ownership
+            ros_message_subscription->provide_intra_process_message(std::move(message));
+            // Last message delivered, break from for loop
+            break;
+          } else {
+            // Copy the message since we have additional subscriptions to serve
+            Deleter deleter = message.get_deleter();
+            allocator::set_allocator_for_deleter(&deleter, &allocator);
+            auto ptr = MessageAllocTraits::allocate(allocator, 1);
+            MessageAllocTraits::construct(allocator, ptr, *message);
 
-        subscription->provide_intra_process_message(std::move(copy_message));
+            ros_message_subscription->provide_intra_process_message(
+              std::move(MessageUniquePtr(ptr, deleter)));
+          }
+        }
       }
     }
   }

rclcpp/include/rclcpp/experimental/ros_message_intra_process_buffer.hpp

@@ -0,0 +1,68 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__EXPERIMENTAL__ROS_MESSAGE_INTRA_PROCESS_BUFFER_HPP_
+#define RCLCPP__EXPERIMENTAL__ROS_MESSAGE_INTRA_PROCESS_BUFFER_HPP_
+
+#include <memory>
+#include <string>
+
+#include "rcl/error_handling.h"
+
+#include "rclcpp/any_subscription_callback.hpp"
+#include "rclcpp/context.hpp"
+#include "rclcpp/experimental/subscription_intra_process_base.hpp"
+#include "tracetools/tracetools.h"
+
+namespace rclcpp
+{
+namespace experimental
+{
+
+template<
+  typename RosMessageT,
+  typename Alloc = std::allocator<void>,
+  typename Deleter = std::default_delete<void>
+>
+class SubscriptionROSMsgIntraProcessBuffer : public SubscriptionIntraProcessBase
+{
+public:
+  using ROSMessageTypeAllocatorTraits = allocator::AllocRebind<RosMessageT, Alloc>;
+  using ROSMessageTypeAllocator = typename ROSMessageTypeAllocatorTraits::allocator_type;
+  using ROSMessageTypeDeleter = allocator::Deleter<ROSMessageTypeAllocator, RosMessageT>;
+
+  using ConstMessageSharedPtr = std::shared_ptr<const RosMessageT>;
+  using MessageUniquePtr = std::unique_ptr<RosMessageT, ROSMessageTypeDeleter>;
+
+  SubscriptionROSMsgIntraProcessBuffer(
+    rclcpp::Context::SharedPtr context,
+    const std::string & topic_name,
+    const rclcpp::QoS & qos_profile)
+  : SubscriptionIntraProcessBase(context, topic_name, qos_profile)
+  {}
+
+  virtual ~SubscriptionROSMsgIntraProcessBuffer()
+  {}
+
+  virtual void
+  provide_intra_process_message(ConstMessageSharedPtr message) = 0;
+
+  virtual void
+  provide_intra_process_message(MessageUniquePtr message) = 0;
+};
+
+}  // namespace experimental
+}  // namespace rclcpp
+
+#endif  // RCLCPP__EXPERIMENTAL__ROS_MESSAGE_INTRA_PROCESS_BUFFER_HPP_

rclcpp/include/rclcpp/experimental/subscription_intra_process.hpp

@@ -15,21 +15,22 @@
 #ifndef RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_HPP_
 #define RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_HPP_
 
-#include <rmw/rmw.h>
+#include <rmw/types.h>
 
-#include <functional>
 #include <memory>
+#include <stdexcept>
 #include <string>
+#include <type_traits>
 #include <utility>
 
-#include "rcl/error_handling.h"
+#include "rcl/types.h"
 
 #include "rclcpp/any_subscription_callback.hpp"
+#include "rclcpp/context.hpp"
 #include "rclcpp/experimental/buffers/intra_process_buffer.hpp"
-#include "rclcpp/experimental/create_intra_process_buffer.hpp"
-#include "rclcpp/experimental/subscription_intra_process_base.hpp"
+#include "rclcpp/experimental/subscription_intra_process_buffer.hpp"
+#include "rclcpp/qos.hpp"
 #include "rclcpp/type_support_decl.hpp"
-#include "rclcpp/waitable.hpp"
 #include "tracetools/tracetools.h"
 
 namespace rclcpp
@@ -39,61 +40,57 @@ namespace experimental
 
 template<
   typename MessageT,
-  typename Alloc = std::allocator<void>,
-  typename Deleter = std::default_delete<MessageT>,
-  typename CallbackMessageT = MessageT>
-class SubscriptionIntraProcess : public SubscriptionIntraProcessBase
+  typename SubscribedType,
+  typename SubscribedTypeAlloc = std::allocator<SubscribedType>,
+  typename SubscribedTypeDeleter = std::default_delete<SubscribedType>,
+  typename ROSMessageType = SubscribedType,
+  typename Alloc = std::allocator<void>
+>
+class SubscriptionIntraProcess
+  : public SubscriptionIntraProcessBuffer<
+    SubscribedType,
+    SubscribedTypeAlloc,
+    SubscribedTypeDeleter,
+    ROSMessageType
+  >
 {
+  using SubscriptionIntraProcessBufferT = SubscriptionIntraProcessBuffer<
+    SubscribedType,
+    SubscribedTypeAlloc,
+    SubscribedTypeDeleter,
+    ROSMessageType
+  >;
+
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(SubscriptionIntraProcess)
 
-  using MessageAllocTraits = allocator::AllocRebind<MessageT, Alloc>;
-  using MessageAlloc = typename MessageAllocTraits::allocator_type;
-  using ConstMessageSharedPtr = std::shared_ptr<const MessageT>;
-  using MessageUniquePtr = std::unique_ptr<MessageT, Deleter>;
-
-  using BufferUniquePtr = typename rclcpp::experimental::buffers::IntraProcessBuffer<
-    MessageT,
-    Alloc,
-    Deleter
-    >::UniquePtr;
+  using MessageAllocTraits =
+    typename SubscriptionIntraProcessBufferT::SubscribedTypeAllocatorTraits;
+  using MessageAlloc = typename SubscriptionIntraProcessBufferT::SubscribedTypeAllocator;
+  using ConstMessageSharedPtr = typename SubscriptionIntraProcessBufferT::ConstDataSharedPtr;
+  using MessageUniquePtr = typename SubscriptionIntraProcessBufferT::SubscribedTypeUniquePtr;
+  using BufferUniquePtr = typename SubscriptionIntraProcessBufferT::BufferUniquePtr;
 
   SubscriptionIntraProcess(
-    AnySubscriptionCallback<CallbackMessageT, Alloc> callback,
+    AnySubscriptionCallback<MessageT, Alloc> callback,
     std::shared_ptr<Alloc> allocator,
     rclcpp::Context::SharedPtr context,
     const std::string & topic_name,
-    rmw_qos_profile_t qos_profile,
+    const rclcpp::QoS & qos_profile,
     rclcpp::IntraProcessBufferType buffer_type)
-  : SubscriptionIntraProcessBase(topic_name, qos_profile),
+  : SubscriptionIntraProcessBuffer<SubscribedType, SubscribedTypeAlloc,
+      SubscribedTypeDeleter, ROSMessageType>(
+      std::make_shared<SubscribedTypeAlloc>(*allocator),
+      context,
+      topic_name,
+      qos_profile,
+      buffer_type),
     any_callback_(callback)
   {
-    if (!std::is_same<MessageT, CallbackMessageT>::value) {
-      throw std::runtime_error("SubscriptionIntraProcess wrong callback type");
-    }
-
-    // Create the intra-process buffer.
-    buffer_ = rclcpp::experimental::create_intra_process_buffer<MessageT, Alloc, Deleter>(
-      buffer_type,
-      qos_profile,
-      allocator);
-
-    // Create the guard condition.
-    rcl_guard_condition_options_t guard_condition_options =
-      rcl_guard_condition_get_default_options();
-
-    gc_ = rcl_get_zero_initialized_guard_condition();
-    rcl_ret_t ret = rcl_guard_condition_init(
-      &gc_, context->get_rcl_context().get(), guard_condition_options);
-
-    if (RCL_RET_OK != ret) {
-      throw std::runtime_error("SubscriptionIntraProcess init error initializing guard condition");
-    }
-
     TRACEPOINT(
       rclcpp_subscription_callback_added,
-      (const void *)this,
-      (const void *)&any_callback_);
+      static_cast<const void *>(this),
+      static_cast<const void *>(&any_callback_));
     // The callback object gets copied, so if registration is done too early/before this point
     // (e.g. in `AnySubscriptionCallback::set()`), its address won't match any address used later
     // in subsequent tracepoints.
@@ -102,72 +99,79 @@ public:
 #endif
   }
 
-  bool
-  is_ready(rcl_wait_set_t * wait_set)
+  virtual ~SubscriptionIntraProcess() = default;
+
+  std::shared_ptr<void>
+  take_data() override
   {
-    (void)wait_set;
-    return buffer_->has_data();
+    ConstMessageSharedPtr shared_msg;
+    MessageUniquePtr unique_msg;
+
+    if (any_callback_.use_take_shared_method()) {
+      shared_msg = this->buffer_->consume_shared();
+      if (!shared_msg) {
+        return nullptr;
+      }
+    } else {
+      unique_msg = this->buffer_->consume_unique();
+      if (!unique_msg) {
+        return nullptr;
+      }
+    }
+
+    if (this->buffer_->has_data()) {
+      // If there is data still to be processed, indicate to the
+      // executor or waitset by triggering the guard condition.
+      this->trigger_guard_condition();
+    }
+
+    return std::static_pointer_cast<void>(
+      std::make_shared<std::pair<ConstMessageSharedPtr, MessageUniquePtr>>(
+        std::pair<ConstMessageSharedPtr, MessageUniquePtr>(
+          shared_msg, std::move(unique_msg)))
+    );
   }
 
-  void execute()
+  void execute(std::shared_ptr<void> & data) override
   {
-    execute_impl<CallbackMessageT>();
-  }
-
-  void
-  provide_intra_process_message(ConstMessageSharedPtr message)
-  {
-    buffer_->add_shared(std::move(message));
-    trigger_guard_condition();
-  }
-
-  void
-  provide_intra_process_message(MessageUniquePtr message)
-  {
-    buffer_->add_unique(std::move(message));
-    trigger_guard_condition();
-  }
-
-  bool
-  use_take_shared_method() const
-  {
-    return buffer_->use_take_shared_method();
-  }
-
-private:
-  void
-  trigger_guard_condition()
-  {
-    rcl_ret_t ret = rcl_trigger_guard_condition(&gc_);
-    (void)ret;
+    execute_impl<SubscribedType>(data);
   }
 
+protected:
   template<typename T>
   typename std::enable_if<std::is_same<T, rcl_serialized_message_t>::value, void>::type
-  execute_impl()
+  execute_impl(std::shared_ptr<void> & data)
   {
+    (void)data;
     throw std::runtime_error("Subscription intra-process can't handle serialized messages");
   }
 
   template<class T>
   typename std::enable_if<!std::is_same<T, rcl_serialized_message_t>::value, void>::type
-  execute_impl()
+  execute_impl(std::shared_ptr<void> & data)
   {
+    if (!data) {
+      return;
+    }
+
     rmw_message_info_t msg_info;
     msg_info.publisher_gid = {0, {0}};
     msg_info.from_intra_process = true;
 
+    auto shared_ptr = std::static_pointer_cast<std::pair<ConstMessageSharedPtr, MessageUniquePtr>>(
+      data);
+
     if (any_callback_.use_take_shared_method()) {
-      ConstMessageSharedPtr msg = buffer_->consume_shared();
-      any_callback_.dispatch_intra_process(msg, msg_info);
+      ConstMessageSharedPtr shared_msg = shared_ptr->first;
+      any_callback_.dispatch_intra_process(shared_msg, msg_info);
     } else {
-      MessageUniquePtr msg = buffer_->consume_unique();
-      any_callback_.dispatch_intra_process(std::move(msg), msg_info);
+      MessageUniquePtr unique_msg = std::move(shared_ptr->second);
+      any_callback_.dispatch_intra_process(std::move(unique_msg), msg_info);
     }
+    shared_ptr.reset();
   }
 
-  AnySubscriptionCallback<CallbackMessageT, Alloc> any_callback_;
-  BufferUniquePtr buffer_;
+  AnySubscriptionCallback<MessageT, Alloc> any_callback_;
 };
 
 }  // namespace experimental

rclcpp/include/rclcpp/experimental/subscription_intra_process_base.hpp

@@ -15,17 +15,17 @@
 #ifndef RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_BASE_HPP_
 #define RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_BASE_HPP_
 
-#include <rmw/rmw.h>
-
-#include <functional>
+#include <algorithm>
 #include <memory>
 #include <mutex>
 #include <string>
-#include <utility>
 
-#include "rcl/error_handling.h"
+#include "rcl/wait.h"
+#include "rmw/impl/cpp/demangle.hpp"
 
-#include "rclcpp/type_support_decl.hpp"
+#include "rclcpp/guard_condition.hpp"
+#include "rclcpp/logging.hpp"
+#include "rclcpp/qos.hpp"
 #include "rclcpp/waitable.hpp"
 
 namespace rclcpp
@@ -38,28 +38,48 @@ class SubscriptionIntraProcessBase : public rclcpp::Waitable
 public:
   RCLCPP_SMART_PTR_ALIASES_ONLY(SubscriptionIntraProcessBase)
 
+  enum class EntityType : std::size_t
+  {
+    Subscription,
+  };
+
   RCLCPP_PUBLIC
-  SubscriptionIntraProcessBase(const std::string & topic_name, rmw_qos_profile_t qos_profile)
-  : topic_name_(topic_name), qos_profile_(qos_profile)
+  SubscriptionIntraProcessBase(
+    rclcpp::Context::SharedPtr context,
+    const std::string & topic_name,
+    const rclcpp::QoS & qos_profile)
+  : gc_(context), topic_name_(topic_name), qos_profile_(qos_profile)
   {}
 
-  virtual ~SubscriptionIntraProcessBase() = default;
+  RCLCPP_PUBLIC
+  virtual ~SubscriptionIntraProcessBase();
 
   RCLCPP_PUBLIC
   size_t
-  get_number_of_ready_guard_conditions() {return 1;}
+  get_number_of_ready_guard_conditions() override {return 1;}
 
   RCLCPP_PUBLIC
+  void
+  add_to_wait_set(rcl_wait_set_t * wait_set) override;
+
   bool
-  add_to_wait_set(rcl_wait_set_t * wait_set);
+  is_ready(rcl_wait_set_t * wait_set) override = 0;
 
-  virtual bool
-  is_ready(rcl_wait_set_t * wait_set) = 0;
+  std::shared_ptr<void>
+  take_data() override = 0;
 
-  virtual void
-  execute() = 0;
+  std::shared_ptr<void>
+  take_data_by_entity_id(size_t id) override
+  {
+    (void)id;
+    return take_data();
+  }
 
-  virtual bool
+  void
+  execute(std::shared_ptr<void> & data) override = 0;
+
+  virtual
+  bool
   use_take_shared_method() const = 0;
 
   RCLCPP_PUBLIC
@@ -67,19 +87,113 @@ public:
   get_topic_name() const;
 
   RCLCPP_PUBLIC
-  rmw_qos_profile_t
+  QoS
   get_actual_qos() const;
 
-protected:
-  std::recursive_mutex reentrant_mutex_;
-  rcl_guard_condition_t gc_;
+  /// Set a callback to be called when each new message arrives.
+  /**
+   * The callback receives a size_t which is the number of messages received
+   * since the last time this callback was called.
+   * Normally this is 1, but can be > 1 if messages were received before any
+   * callback was set.
+   *
+   * The callback also receives an int identifier argument.
+   * This is needed because a Waitable may be composed of several distinct entities,
+   * such as subscriptions, services, etc.
+   * The application should provide a generic callback function that will be then
+   * forwarded by the waitable to all of its entities.
+   * Before forwarding, a different value for the identifier argument will be
+   * bound to the function.
+   * This implies that the provided callback can use the identifier to behave
+   * differently depending on which entity triggered the waitable to become ready.
+   *
+   * Calling it again will clear any previously set callback.
+   *
+   * An exception will be thrown if the callback is not callable.
+   *
+   * This function is thread-safe.
+   *
+   * If you want more information available in the callback, like the subscription
+   * or other information, you may use a lambda with captures or std::bind.
+   *
+   * \param[in] callback functor to be called when a new message is received.
+   */
+  void
+  set_on_ready_callback(std::function<void(size_t, int)> callback) override
+  {
+    if (!callback) {
+      throw std::invalid_argument(
+              "The callback passed to set_on_ready_callback "
+              "is not callable.");
+    }
+
+    // Note: we bind the int identifier argument to this waitable's entity types
+    auto new_callback =
+      [callback, this](size_t number_of_events) {
+        try {
+          callback(number_of_events, static_cast<int>(EntityType::Subscription));
+        } catch (const std::exception & exception) {
+          RCLCPP_ERROR_STREAM(
+            // TODO(wjwwood): get this class access to the node logger it is associated with
+            rclcpp::get_logger("rclcpp"),
+            "rclcpp::SubscriptionIntraProcessBase@" << this <<
+              " caught " << rmw::impl::cpp::demangle(exception) <<
+              " exception in user-provided callback for the 'on ready' callback: " <<
+              exception.what());
+        } catch (...) {
+          RCLCPP_ERROR_STREAM(
+            rclcpp::get_logger("rclcpp"),
+            "rclcpp::SubscriptionIntraProcessBase@" << this <<
+              " caught unhandled exception in user-provided callback " <<
+              "for the 'on ready' callback");
+        }
+      };
+
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+    on_new_message_callback_ = new_callback;
+
+    if (unread_count_ > 0) {
+      if (qos_profile_.history() == HistoryPolicy::KeepAll) {
+        on_new_message_callback_(unread_count_);
+      } else {
+        // Use qos profile depth as upper bound for unread_count_
+        on_new_message_callback_(std::min(unread_count_, qos_profile_.depth()));
+      }
+      unread_count_ = 0;
+    }
+  }
+
+  /// Unset the callback registered for new messages, if any.
+  void
+  clear_on_ready_callback() override
+  {
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+    on_new_message_callback_ = nullptr;
+  }
+
+protected:
+  std::recursive_mutex callback_mutex_;
+  std::function<void(size_t)> on_new_message_callback_ {nullptr};
+  size_t unread_count_{0};
+  rclcpp::GuardCondition gc_;
 
-private:
   virtual void
   trigger_guard_condition() = 0;
 
+  void
+  invoke_on_new_message()
+  {
+    std::lock_guard<std::recursive_mutex> lock(this->callback_mutex_);
+    if (this->on_new_message_callback_) {
+      this->on_new_message_callback_(1);
+    } else {
+      this->unread_count_++;
+    }
+  }
+
+private:
   std::string topic_name_;
-  rmw_qos_profile_t qos_profile_;
+  QoS qos_profile_;
 };
 
 }  // namespace experimental

rclcpp/include/rclcpp/experimental/subscription_intra_process_buffer.hpp

@@ -0,0 +1,181 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_BUFFER_HPP_
+#define RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_BUFFER_HPP_
+
+#include <memory>
+#include <string>
+#include <stdexcept>
+#include <utility>
+
+#include "rcl/error_handling.h"
+#include "rcl/guard_condition.h"
+#include "rcl/wait.h"
+
+#include "rclcpp/experimental/buffers/intra_process_buffer.hpp"
+#include "rclcpp/experimental/create_intra_process_buffer.hpp"
+#include "rclcpp/experimental/subscription_intra_process_base.hpp"
+#include "rclcpp/experimental/ros_message_intra_process_buffer.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/type_support_decl.hpp"
+
+namespace rclcpp
+{
+namespace experimental
+{
+
+template<
+  typename SubscribedType,
+  typename Alloc = std::allocator<SubscribedType>,
+  typename Deleter = std::default_delete<SubscribedType>,
+  /// MessageT::ros_message_type if MessageT is a TypeAdapter,
+  /// otherwise just MessageT.
+  typename ROSMessageType = SubscribedType
+>
+class SubscriptionIntraProcessBuffer : public SubscriptionROSMsgIntraProcessBuffer<ROSMessageType,
+    typename allocator::AllocRebind<ROSMessageType, Alloc>::allocator_type,
+    allocator::Deleter<typename allocator::AllocRebind<ROSMessageType, Alloc>::allocator_type,
+    ROSMessageType>>
+{
+public:
+  RCLCPP_SMART_PTR_DEFINITIONS(SubscriptionIntraProcessBuffer)
+
+  using SubscribedTypeAllocatorTraits = allocator::AllocRebind<SubscribedType, Alloc>;
+  using SubscribedTypeAllocator = typename SubscribedTypeAllocatorTraits::allocator_type;
+  using SubscribedTypeDeleter = allocator::Deleter<SubscribedTypeAllocator, SubscribedType>;
+
+  using ROSMessageTypeAllocatorTraits = allocator::AllocRebind<ROSMessageType, Alloc>;
+  using ROSMessageTypeAllocator = typename ROSMessageTypeAllocatorTraits::allocator_type;
+  using ROSMessageTypeDeleter = allocator::Deleter<ROSMessageTypeAllocator, ROSMessageType>;
+
+  using ConstMessageSharedPtr = std::shared_ptr<const ROSMessageType>;
+  using MessageUniquePtr = std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>;
+
+  using ConstDataSharedPtr = std::shared_ptr<const SubscribedType>;
+  using SubscribedTypeUniquePtr = std::unique_ptr<SubscribedType, SubscribedTypeDeleter>;
+
+  using BufferUniquePtr = typename rclcpp::experimental::buffers::IntraProcessBuffer<
+    SubscribedType,
+    Alloc,
+    SubscribedTypeDeleter
+    >::UniquePtr;
+
+  SubscriptionIntraProcessBuffer(
+    std::shared_ptr<Alloc> allocator,
+    rclcpp::Context::SharedPtr context,
+    const std::string & topic_name,
+    const rclcpp::QoS & qos_profile,
+    rclcpp::IntraProcessBufferType buffer_type)
+  : SubscriptionROSMsgIntraProcessBuffer<ROSMessageType, ROSMessageTypeAllocator,
+      ROSMessageTypeDeleter>(
+      context, topic_name, qos_profile),
+    subscribed_type_allocator_(*allocator)
+  {
+    allocator::set_allocator_for_deleter(&subscribed_type_deleter_, &subscribed_type_allocator_);
+
+    // Create the intra-process buffer.
+    buffer_ = rclcpp::experimental::create_intra_process_buffer<SubscribedType, Alloc,
+        SubscribedTypeDeleter>(
+      buffer_type,
+      qos_profile,
+      std::make_shared<Alloc>(subscribed_type_allocator_));
+  }
+
+  bool
+  is_ready(rcl_wait_set_t * wait_set) override
+  {
+    (void) wait_set;
+    return buffer_->has_data();
+  }
+
+  SubscribedTypeUniquePtr
+  convert_ros_message_to_subscribed_type_unique_ptr(const ROSMessageType & msg)
+  {
+    if constexpr (!std::is_same<SubscribedType, ROSMessageType>::value) {
+      auto ptr = SubscribedTypeAllocatorTraits::allocate(subscribed_type_allocator_, 1);
+      SubscribedTypeAllocatorTraits::construct(subscribed_type_allocator_, ptr);
+      rclcpp::TypeAdapter<SubscribedType, ROSMessageType>::convert_to_custom(msg, *ptr);
+      return SubscribedTypeUniquePtr(ptr, subscribed_type_deleter_);
+    } else {
+      throw std::runtime_error(
+              "convert_ros_message_to_subscribed_type_unique_ptr "
+              "unexpectedly called without TypeAdapter");
+    }
+  }
+
+  void
+  provide_intra_process_message(ConstMessageSharedPtr message) override
+  {
+    if constexpr (std::is_same<SubscribedType, ROSMessageType>::value) {
+      buffer_->add_shared(std::move(message));
+      trigger_guard_condition();
+    } else {
+      buffer_->add_shared(convert_ros_message_to_subscribed_type_unique_ptr(*message));
+      trigger_guard_condition();
+    }
+    this->invoke_on_new_message();
+  }
+
+  void
+  provide_intra_process_message(MessageUniquePtr message) override
+  {
+    if constexpr (std::is_same<SubscribedType, ROSMessageType>::value) {
+      buffer_->add_unique(std::move(message));
+      trigger_guard_condition();
+    } else {
+      buffer_->add_unique(convert_ros_message_to_subscribed_type_unique_ptr(*message));
+      trigger_guard_condition();
+    }
+    this->invoke_on_new_message();
+  }
+
+  void
+  provide_intra_process_data(ConstDataSharedPtr message)
+  {
+    buffer_->add_shared(std::move(message));
+    trigger_guard_condition();
+    this->invoke_on_new_message();
+  }
+
+  void
+  provide_intra_process_data(SubscribedTypeUniquePtr message)
+  {
+    buffer_->add_unique(std::move(message));
+    trigger_guard_condition();
+    this->invoke_on_new_message();
+  }
+
+  bool
+  use_take_shared_method() const override
+  {
+    return buffer_->use_take_shared_method();
+  }
+
+protected:
+  void
+  trigger_guard_condition() override
+  {
+    this->gc_.trigger();
+  }
+
+  BufferUniquePtr buffer_;
+  SubscribedTypeAllocator subscribed_type_allocator_;
+  SubscribedTypeDeleter subscribed_type_deleter_;
+};
+
+}  // namespace experimental
+}  // namespace rclcpp
+
+#endif  // RCLCPP__EXPERIMENTAL__SUBSCRIPTION_INTRA_PROCESS_BUFFER_HPP_

rclcpp/include/rclcpp/function_traits.hpp

@@ -80,10 +80,12 @@ struct function_traits<ReturnTypeT (*)(Args ...)>: function_traits<ReturnTypeT(A
 
 // std::bind for object methods
 template<typename ClassT, typename ReturnTypeT, typename ... Args, typename ... FArgs>
-#if defined _LIBCPP_VERSION  // libc++ (Clang)
+#if defined DOXYGEN_ONLY
+struct function_traits<std::bind<ReturnTypeT (ClassT::*)(Args ...), FArgs ...>>
+#elif defined _LIBCPP_VERSION  // libc++ (Clang)
 struct function_traits<std::__bind<ReturnTypeT (ClassT::*)(Args ...), FArgs ...>>
 #elif defined _GLIBCXX_RELEASE  // glibc++ (GNU C++ >= 7.1)
-struct function_traits<std::_Bind<ReturnTypeT(ClassT::*(FArgs ...))(Args ...)>>
+struct function_traits<std::_Bind<ReturnTypeT(ClassT::* (FArgs ...))(Args ...)>>
 #elif defined __GLIBCXX__  // glibc++ (GNU C++)
 struct function_traits<std::_Bind<std::_Mem_fn<ReturnTypeT (ClassT::*)(Args ...)>(FArgs ...)>>
 #elif defined _MSC_VER  // MS Visual Studio
@@ -97,10 +99,12 @@ struct function_traits<
 
 // std::bind for object const methods
 template<typename ClassT, typename ReturnTypeT, typename ... Args, typename ... FArgs>
-#if defined _LIBCPP_VERSION  // libc++ (Clang)
+#if defined DOXYGEN_ONLY
+struct function_traits<std::bind<ReturnTypeT (ClassT::*)(Args ...) const, FArgs ...>>
+#elif defined _LIBCPP_VERSION  // libc++ (Clang)
 struct function_traits<std::__bind<ReturnTypeT (ClassT::*)(Args ...) const, FArgs ...>>
 #elif defined _GLIBCXX_RELEASE  // glibc++ (GNU C++ >= 7.1)
-struct function_traits<std::_Bind<ReturnTypeT(ClassT::*(FArgs ...))(Args ...) const>>
+struct function_traits<std::_Bind<ReturnTypeT(ClassT::* (FArgs ...))(Args ...) const>>
 #elif defined __GLIBCXX__  // glibc++ (GNU C++)
 struct function_traits<std::_Bind<std::_Mem_fn<ReturnTypeT (ClassT::*)(Args ...) const>(FArgs ...)>>
 #elif defined _MSC_VER  // MS Visual Studio
@@ -114,7 +118,9 @@ struct function_traits<
 
 // std::bind for free functions
 template<typename ReturnTypeT, typename ... Args, typename ... FArgs>
-#if defined _LIBCPP_VERSION  // libc++ (Clang)
+#if defined DOXYGEN_ONLY
+struct function_traits<std::bind<ReturnTypeT( &)(Args ...), FArgs ...>>
+#elif defined _LIBCPP_VERSION  // libc++ (Clang)
 struct function_traits<std::__bind<ReturnTypeT( &)(Args ...), FArgs ...>>
 #elif defined __GLIBCXX__  // glibc++ (GNU C++)
 struct function_traits<std::_Bind<ReturnTypeT(*(FArgs ...))(Args ...)>>
@@ -162,6 +168,32 @@ struct same_arguments : std::is_same<
 >
 {};
 
+namespace detail
+{
+
+template<typename ReturnTypeT, typename ... Args>
+struct as_std_function_helper;
+
+template<typename ReturnTypeT, typename ... Args>
+struct as_std_function_helper<ReturnTypeT, std::tuple<Args ...>>
+{
+  using type = std::function<ReturnTypeT(Args ...)>;
+};
+
+}  // namespace detail
+
+template<
+  typename FunctorT,
+  typename FunctionTraits = function_traits<FunctorT>
+>
+struct as_std_function
+{
+  using type = typename detail::as_std_function_helper<
+    typename FunctionTraits::return_type,
+    typename FunctionTraits::arguments
+    >::type;
+};
+
 }  // namespace function_traits
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/future_return_code.hpp

@@ -42,12 +42,6 @@ RCLCPP_PUBLIC
 std::string
 to_string(const FutureReturnCode & future_return_code);
 
-namespace executor
-{
-
-using FutureReturnCode [[deprecated("use rclcpp::FutureReturnCode instead")]] = FutureReturnCode;
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__FUTURE_RETURN_CODE_HPP_

rclcpp/include/rclcpp/generic_publisher.hpp

@@ -0,0 +1,143 @@
+// Copyright 2018, Bosch Software Innovations GmbH.
+// Copyright 2021, Apex.AI Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__GENERIC_PUBLISHER_HPP_
+#define RCLCPP__GENERIC_PUBLISHER_HPP_
+
+#include <memory>
+#include <string>
+
+#include "rcpputils/shared_library.hpp"
+
+#include "rclcpp/callback_group.hpp"
+#include "rclcpp/macros.hpp"
+#include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/publisher_base.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/serialized_message.hpp"
+#include "rclcpp/typesupport_helpers.hpp"
+#include "rclcpp/visibility_control.hpp"
+
+#include "rmw/rmw.h"
+
+namespace rclcpp
+{
+
+/// %Publisher for serialized messages whose type is not known at compile time.
+/**
+ * Since the type is not known at compile time, this is not a template, and the dynamic library
+ * containing type support information has to be identified and loaded based on the type name.
+ *
+ * It does not support intra-process handling.
+ */
+class GenericPublisher : public rclcpp::PublisherBase
+{
+public:
+  // cppcheck-suppress unknownMacro
+  RCLCPP_SMART_PTR_DEFINITIONS(GenericPublisher)
+
+  /// Constructor.
+  /**
+   * In order to properly publish to a topic, this publisher needs to be added to
+   * the node_topic_interface of the node passed into this constructor.
+   *
+   * \sa rclcpp::Node::create_generic_publisher() or rclcpp::create_generic_publisher() for
+   * creating an instance of this class and adding it to the node_topic_interface.
+   *
+   * \param node_base Pointer to parent node's NodeBaseInterface
+   * \param ts_lib Type support library, needs to correspond to topic_type
+   * \param topic_name Topic name
+   * \param topic_type Topic type
+   * \param qos %QoS settings
+   * \param options %Publisher options.
+   * Not all publisher options are currently respected, the only relevant options for this
+   * publisher are `event_callbacks`, `use_default_callbacks`, and `%callback_group`.
+   */
+  template<typename AllocatorT = std::allocator<void>>
+  GenericPublisher(
+    rclcpp::node_interfaces::NodeBaseInterface * node_base,
+    std::shared_ptr<rcpputils::SharedLibrary> ts_lib,
+    const std::string & topic_name,
+    const std::string & topic_type,
+    const rclcpp::QoS & qos,
+    const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options)
+  : rclcpp::PublisherBase(
+      node_base,
+      topic_name,
+      *rclcpp::get_typesupport_handle(topic_type, "rosidl_typesupport_cpp", *ts_lib),
+      options.template to_rcl_publisher_options<rclcpp::SerializedMessage>(qos)),
+    ts_lib_(ts_lib)
+  {
+    // This is unfortunately duplicated with the code in publisher.hpp.
+    // TODO(nnmm): Deduplicate by moving this into PublisherBase.
+    if (options.event_callbacks.deadline_callback) {
+      this->add_event_handler(
+        options.event_callbacks.deadline_callback,
+        RCL_PUBLISHER_OFFERED_DEADLINE_MISSED);
+    }
+    if (options.event_callbacks.liveliness_callback) {
+      this->add_event_handler(
+        options.event_callbacks.liveliness_callback,
+        RCL_PUBLISHER_LIVELINESS_LOST);
+    }
+    if (options.event_callbacks.incompatible_qos_callback) {
+      this->add_event_handler(
+        options.event_callbacks.incompatible_qos_callback,
+        RCL_PUBLISHER_OFFERED_INCOMPATIBLE_QOS);
+    } else if (options.use_default_callbacks) {
+      // Register default callback when not specified
+      try {
+        this->add_event_handler(
+          [this](QOSOfferedIncompatibleQoSInfo & info) {
+            this->default_incompatible_qos_callback(info);
+          },
+          RCL_PUBLISHER_OFFERED_INCOMPATIBLE_QOS);
+      } catch (UnsupportedEventTypeException & /*exc*/) {
+        // pass
+      }
+    }
+  }
+
+  RCLCPP_PUBLIC
+  virtual ~GenericPublisher() = default;
+
+  /// Publish a rclcpp::SerializedMessage.
+  RCLCPP_PUBLIC
+  void publish(const rclcpp::SerializedMessage & message);
+
+  /**
+   * Publish a rclcpp::SerializedMessage via loaned message after de-serialization.
+   *
+   * \param message a serialized message
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can show
+   */
+  RCLCPP_PUBLIC
+  void publish_as_loaned_msg(const rclcpp::SerializedMessage & message);
+
+private:
+  // The type support library should stay loaded, so it is stored in the GenericPublisher
+  std::shared_ptr<rcpputils::SharedLibrary> ts_lib_;
+
+  void * borrow_loaned_message();
+  void deserialize_message(
+    const rmw_serialized_message_t & serialized_message,
+    void * deserialized_msg);
+  void publish_loaned_message(void * loaned_message);
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__GENERIC_PUBLISHER_HPP_

rclcpp/include/rclcpp/generic_subscription.hpp

@@ -0,0 +1,168 @@
+// Copyright 2018, Bosch Software Innovations GmbH.
+// Copyright 2021, Apex.AI Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__GENERIC_SUBSCRIPTION_HPP_
+#define RCLCPP__GENERIC_SUBSCRIPTION_HPP_
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "rcpputils/shared_library.hpp"
+
+#include "rclcpp/callback_group.hpp"
+#include "rclcpp/macros.hpp"
+#include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/serialized_message.hpp"
+#include "rclcpp/subscription_base.hpp"
+#include "rclcpp/typesupport_helpers.hpp"
+#include "rclcpp/visibility_control.hpp"
+
+namespace rclcpp
+{
+
+/// %Subscription for serialized messages whose type is not known at compile time.
+/**
+ * Since the type is not known at compile time, this is not a template, and the dynamic library
+ * containing type support information has to be identified and loaded based on the type name.
+ *
+ * It does not support intra-process handling.
+ */
+class GenericSubscription : public rclcpp::SubscriptionBase
+{
+public:
+  // cppcheck-suppress unknownMacro
+  RCLCPP_SMART_PTR_DEFINITIONS(GenericSubscription)
+
+  /// Constructor.
+  /**
+   * In order to properly subscribe to a topic, this subscription needs to be added to
+   * the node_topic_interface of the node passed into this constructor.
+   *
+   * \sa rclcpp::Node::create_generic_subscription() or rclcpp::create_generic_subscription() for
+   * creating an instance of this class and adding it to the node_topic_interface.
+   *
+   * \param node_base Pointer to parent node's NodeBaseInterface
+   * \param ts_lib Type support library, needs to correspond to topic_type
+   * \param topic_name Topic name
+   * \param topic_type Topic type
+   * \param qos %QoS settings
+   * \param callback Callback for new messages of serialized form
+   * \param options %Subscription options.
+   * Not all subscription options are currently respected, the only relevant options for this
+   * subscription are `event_callbacks`, `use_default_callbacks`, `ignore_local_publications`, and
+   * `%callback_group`.
+   */
+  template<typename AllocatorT = std::allocator<void>>
+  GenericSubscription(
+    rclcpp::node_interfaces::NodeBaseInterface * node_base,
+    const std::shared_ptr<rcpputils::SharedLibrary> ts_lib,
+    const std::string & topic_name,
+    const std::string & topic_type,
+    const rclcpp::QoS & qos,
+    // TODO(nnmm): Add variant for callback with message info. See issue #1604.
+    std::function<void(std::shared_ptr<rclcpp::SerializedMessage>)> callback,
+    const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options)
+  : SubscriptionBase(
+      node_base,
+      *rclcpp::get_typesupport_handle(topic_type, "rosidl_typesupport_cpp", *ts_lib),
+      topic_name,
+      options.template to_rcl_subscription_options<rclcpp::SerializedMessage>(qos),
+      true),
+    callback_(callback),
+    ts_lib_(ts_lib)
+  {
+    // This is unfortunately duplicated with the code in subscription.hpp.
+    // TODO(nnmm): Deduplicate by moving this into SubscriptionBase.
+    if (options.event_callbacks.deadline_callback) {
+      this->add_event_handler(
+        options.event_callbacks.deadline_callback,
+        RCL_SUBSCRIPTION_REQUESTED_DEADLINE_MISSED);
+    }
+    if (options.event_callbacks.liveliness_callback) {
+      this->add_event_handler(
+        options.event_callbacks.liveliness_callback,
+        RCL_SUBSCRIPTION_LIVELINESS_CHANGED);
+    }
+    if (options.event_callbacks.incompatible_qos_callback) {
+      this->add_event_handler(
+        options.event_callbacks.incompatible_qos_callback,
+        RCL_SUBSCRIPTION_REQUESTED_INCOMPATIBLE_QOS);
+    } else if (options.use_default_callbacks) {
+      // Register default callback when not specified
+      try {
+        this->add_event_handler(
+          [this](QOSRequestedIncompatibleQoSInfo & info) {
+            this->default_incompatible_qos_callback(info);
+          },
+          RCL_SUBSCRIPTION_REQUESTED_INCOMPATIBLE_QOS);
+      } catch (UnsupportedEventTypeException & /*exc*/) {
+        // pass
+      }
+    }
+    if (options.event_callbacks.message_lost_callback) {
+      this->add_event_handler(
+        options.event_callbacks.message_lost_callback,
+        RCL_SUBSCRIPTION_MESSAGE_LOST);
+    }
+  }
+
+  RCLCPP_PUBLIC
+  virtual ~GenericSubscription() = default;
+
+  // Same as create_serialized_message() as the subscription is to serialized_messages only
+  RCLCPP_PUBLIC
+  std::shared_ptr<void> create_message() override;
+
+  RCLCPP_PUBLIC
+  std::shared_ptr<rclcpp::SerializedMessage> create_serialized_message() override;
+
+  /// Cast the message to a rclcpp::SerializedMessage and call the callback.
+  RCLCPP_PUBLIC
+  void handle_message(
+    std::shared_ptr<void> & message, const rclcpp::MessageInfo & message_info) override;
+
+  /// Handle dispatching rclcpp::SerializedMessage to user callback.
+  RCLCPP_PUBLIC
+  void
+  handle_serialized_message(
+    const std::shared_ptr<rclcpp::SerializedMessage> & serialized_message,
+    const rclcpp::MessageInfo & message_info) override;
+
+  /// This function is currently not implemented.
+  RCLCPP_PUBLIC
+  void handle_loaned_message(
+    void * loaned_message, const rclcpp::MessageInfo & message_info) override;
+
+  // Same as return_serialized_message() as the subscription is to serialized_messages only
+  RCLCPP_PUBLIC
+  void return_message(std::shared_ptr<void> & message) override;
+
+  RCLCPP_PUBLIC
+  void return_serialized_message(std::shared_ptr<rclcpp::SerializedMessage> & message) override;
+
+private:
+  RCLCPP_DISABLE_COPY(GenericSubscription)
+
+  std::function<void(std::shared_ptr<rclcpp::SerializedMessage>)> callback_;
+  // The type support library should stay loaded, so it is stored in the GenericSubscription
+  std::shared_ptr<rcpputils::SharedLibrary> ts_lib_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__GENERIC_SUBSCRIPTION_HPP_

rclcpp/include/rclcpp/get_message_type_support_handle.hpp

@@ -0,0 +1,98 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__GET_MESSAGE_TYPE_SUPPORT_HANDLE_HPP_
+#define RCLCPP__GET_MESSAGE_TYPE_SUPPORT_HANDLE_HPP_
+
+#include <type_traits>
+
+#include "rosidl_runtime_cpp/traits.hpp"
+#include "rosidl_runtime_cpp/message_type_support_decl.hpp"
+#include "rosidl_typesupport_cpp/message_type_support.hpp"
+
+#include "rclcpp/type_adapter.hpp"
+
+/// Versions of rosidl_typesupport_cpp::get_message_type_support_handle that handle adapted types.
+
+namespace rclcpp
+{
+
+#ifdef DOXYGEN_ONLY
+
+/// Returns the message type support for the given `MessageT` type.
+/**
+ * \tparam MessageT an actual ROS message type or an adapted type using `rclcpp::TypeAdapter`
+ */
+template<typename MessageT>
+constexpr const rosidl_message_type_support_t & get_message_type_support_handle();
+
+#else
+
+template<typename MessageT>
+constexpr
+typename std::enable_if_t<
+  rosidl_generator_traits::is_message<MessageT>::value,
+  const rosidl_message_type_support_t &
+>
+get_message_type_support_handle()
+{
+  auto handle = rosidl_typesupport_cpp::get_message_type_support_handle<MessageT>();
+  if (!handle) {
+    throw std::runtime_error("Type support handle unexpectedly nullptr");
+  }
+  return *handle;
+}
+
+template<typename AdaptedType>
+constexpr
+typename std::enable_if_t<
+  !rosidl_generator_traits::is_message<AdaptedType>::value &&
+  rclcpp::TypeAdapter<AdaptedType>::is_specialized::value,
+  const rosidl_message_type_support_t &
+>
+get_message_type_support_handle()
+{
+  auto handle = rosidl_typesupport_cpp::get_message_type_support_handle<
+    typename TypeAdapter<AdaptedType>::ros_message_type
+    >();
+  if (!handle) {
+    throw std::runtime_error("Type support handle unexpectedly nullptr");
+  }
+  return *handle;
+}
+
+// This specialization is a pass through runtime check, which allows a better
+// static_assert to catch this issue further down the line.
+// This should never get to be called in practice, and is purely defensive.
+template<
+  typename AdaptedType
+>
+constexpr
+typename std::enable_if_t<
+  !rosidl_generator_traits::is_message<AdaptedType>::value &&
+  !TypeAdapter<AdaptedType>::is_specialized::value,
+  const rosidl_message_type_support_t &
+>
+get_message_type_support_handle()
+{
+  throw std::runtime_error(
+          "this specialization of rclcpp::get_message_type_support_handle() "
+          "should never be called");
+}
+
+#endif
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__GET_MESSAGE_TYPE_SUPPORT_HANDLE_HPP_

rclcpp/include/rclcpp/graph_listener.hpp

@@ -24,6 +24,7 @@
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
 #include "rclcpp/context.hpp"
+#include "rclcpp/guard_condition.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_graph_interface.hpp"
 #include "rclcpp/visibility_control.hpp"
@@ -63,7 +64,7 @@ class GraphListener : public std::enable_shared_from_this<GraphListener>
 {
 public:
   RCLCPP_PUBLIC
-  explicit GraphListener(std::shared_ptr<rclcpp::Context> parent_context);
+  explicit GraphListener(const rclcpp::Context::SharedPtr & parent_context);
 
   RCLCPP_PUBLIC
   virtual ~GraphListener();
@@ -73,6 +74,8 @@ public:
    * This function is thread-safe.
    *
    * \throws GraphListenerShutdownError if the GraphListener is shutdown
+   * \throws std::runtime if the parent context was destroyed
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
    */
   RCLCPP_PUBLIC
   virtual
@@ -158,14 +161,23 @@ protected:
   void
   run_loop();
 
+  RCLCPP_PUBLIC
+  void
+  init_wait_set();
+
+  RCLCPP_PUBLIC
+  void
+  cleanup_wait_set();
+
 private:
   RCLCPP_DISABLE_COPY(GraphListener)
 
   /** \internal */
   void
-  __shutdown(bool);
+  __shutdown();
 
-  rclcpp::Context::WeakPtr parent_context_;
+  std::weak_ptr<rclcpp::Context> weak_parent_context_;
+  std::shared_ptr<rcl_context_t> rcl_parent_context_;
 
   std::thread listener_thread_;
   bool is_started_;
@@ -176,8 +188,7 @@ private:
   mutable std::mutex node_graph_interfaces_mutex_;
   std::vector<rclcpp::node_interfaces::NodeGraphInterface *> node_graph_interfaces_;
 
-  rcl_guard_condition_t interrupt_guard_condition_ = rcl_get_zero_initialized_guard_condition();
-  rcl_guard_condition_t * shutdown_guard_condition_;
+  rclcpp::GuardCondition interrupt_guard_condition_;
   rcl_wait_set_t wait_set_ = rcl_get_zero_initialized_wait_set();
 };
 

rclcpp/include/rclcpp/guard_condition.hpp

@@ -40,6 +40,8 @@ public:
    *   Defaults to using the global default context singleton.
    *   Shared ownership of the context is held with the guard condition until
    *   destruction.
+   * \param[in] guard_condition_options Optional guard condition options to be used.
+   *   Defaults to using the default guard condition options.
    * \throws std::invalid_argument if the context is nullptr.
    * \throws rclcpp::exceptions::RCLError based exceptions when underlying
    *   rcl functions fail.
@@ -47,7 +49,9 @@ public:
   RCLCPP_PUBLIC
   explicit GuardCondition(
     rclcpp::Context::SharedPtr context =
-    rclcpp::contexts::get_global_default_context());
+    rclcpp::contexts::get_global_default_context(),
+    rcl_guard_condition_options_t guard_condition_options =
+    rcl_guard_condition_get_default_options());
 
   RCLCPP_PUBLIC
   virtual
@@ -58,6 +62,11 @@ public:
   rclcpp::Context::SharedPtr
   get_context() const;
 
+  /// Return the underlying rcl guard condition structure.
+  RCLCPP_PUBLIC
+  rcl_guard_condition_t &
+  get_rcl_guard_condition();
+
   /// Return the underlying rcl guard condition structure.
   RCLCPP_PUBLIC
   const rcl_guard_condition_t &
@@ -89,10 +98,27 @@ public:
   bool
   exchange_in_use_by_wait_set_state(bool in_use_state);
 
+  /// Adds the guard condition to a waitset
+  /**
+   * This function is thread-safe.
+   * \param[in] wait_set pointer to a wait set where to add the guard condition
+   */
+  RCLCPP_PUBLIC
+  void
+  add_to_wait_set(rcl_wait_set_t * wait_set);
+
+  RCLCPP_PUBLIC
+  void
+  set_on_trigger_callback(std::function<void(size_t)> callback);
+
 protected:
   rclcpp::Context::SharedPtr context_;
   rcl_guard_condition_t rcl_guard_condition_;
   std::atomic<bool> in_use_by_wait_set_{false};
+  std::recursive_mutex reentrant_mutex_;
+  std::function<void(size_t)> on_trigger_callback_{nullptr};
+  size_t unread_count_{0};
+  rcl_wait_set_t * wait_set_{nullptr};
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/init_options.hpp

@@ -16,6 +16,7 @@
 #define RCLCPP__INIT_OPTIONS_HPP_
 
 #include <memory>
+#include <mutex>
 
 #include "rcl/init_options.h"
 #include "rclcpp/visibility_control.hpp"
@@ -28,13 +29,23 @@ class InitOptions
 {
 public:
   /// If true, the context will be shutdown on SIGINT by the signal handler (if it was installed).
-  bool shutdown_on_sigint = true;
+  bool shutdown_on_signal = true;
 
-  /// Constructor which allows you to specify the allocator used within the init options.
+  /// Constructor
+  /**
+   * It allows you to specify the allocator used within the init options.
+   * \param[in] allocator used allocate memory within the init options
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
+   */
   RCLCPP_PUBLIC
   explicit InitOptions(rcl_allocator_t allocator = rcl_get_default_allocator());
 
   /// Constructor which is initialized by an existing init_options.
+  /**
+   * Initialized by an existing init_options.
+   * \param[in] init_options rcl_init_options_t to initialized
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
+   */
   RCLCPP_PUBLIC
   explicit InitOptions(const rcl_init_options_t & init_options);
 
@@ -42,6 +53,16 @@ public:
   RCLCPP_PUBLIC
   InitOptions(const InitOptions & other);
 
+  /// Return `true` if logging should be initialized when `rclcpp::Context::init` is called.
+  RCLCPP_PUBLIC
+  bool
+  auto_initialize_logging() const;
+
+  /// Set flag indicating if logging should be initialized or not.
+  RCLCPP_PUBLIC
+  InitOptions &
+  auto_initialize_logging(bool initialize_logging);
+
   /// Assignment operator.
   RCLCPP_PUBLIC
   InitOptions &
@@ -52,16 +73,40 @@ public:
   ~InitOptions();
 
   /// Return the rcl init options.
+  /**
+   * \return the rcl init options.
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
+   */
   RCLCPP_PUBLIC
   const rcl_init_options_t *
   get_rcl_init_options() const;
 
+  /// Retrieve default domain id and set.
+  RCLCPP_PUBLIC
+  void
+  use_default_domain_id();
+
+  /// Set the domain id.
+  RCLCPP_PUBLIC
+  void
+  set_domain_id(size_t domain_id);
+
+  /// Return domain id.
+  RCLCPP_PUBLIC
+  size_t
+  get_domain_id() const;
+
 protected:
   void
   finalize_init_options();
 
 private:
+  void
+  finalize_init_options_impl();
+
+  mutable std::mutex init_options_mutex_;
   std::unique_ptr<rcl_init_options_t> init_options_;
+  bool initialize_logging_{true};
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/is_ros_compatible_type.hpp

@@ -0,0 +1,35 @@
+// Copyright 2021 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__IS_ROS_COMPATIBLE_TYPE_HPP_
+#define RCLCPP__IS_ROS_COMPATIBLE_TYPE_HPP_
+
+#include "rosidl_runtime_cpp/traits.hpp"
+
+#include "rclcpp/type_adapter.hpp"
+
+namespace rclcpp
+{
+
+template<typename T>
+struct is_ros_compatible_type
+{
+  static constexpr bool value =
+    rosidl_generator_traits::is_message<T>::value ||
+    rclcpp::TypeAdapter<T>::is_specialized::value;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__IS_ROS_COMPATIBLE_TYPE_HPP_

rclcpp/include/rclcpp/loaned_message.hpp

@@ -52,8 +52,9 @@ public:
    * However, this user code is ought to be usable even when dynamically linked against
    * a middleware which doesn't support message loaning in which case the allocator will be used.
    *
-   * \param pub rclcpp::Publisher instance to which the memory belongs
-   * \param allocator Allocator instance in case middleware can not allocate messages
+   * \param[in] pub rclcpp::Publisher instance to which the memory belongs
+   * \param[in] allocator Allocator instance in case middleware can not allocate messages
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
    */
   LoanedMessage(
     const rclcpp::PublisherBase & pub,
@@ -65,7 +66,7 @@ public:
     if (pub_.can_loan_messages()) {
       void * message_ptr = nullptr;
       auto ret = rcl_borrow_loaned_message(
-        pub_.get_publisher_handle(),
+        pub_.get_publisher_handle().get(),
         rosidl_typesupport_cpp::get_message_type_support_handle<MessageT>(),
         &message_ptr);
       if (RCL_RET_OK != ret) {
@@ -98,9 +99,13 @@ public:
    * However, this user code is ought to be usable even when dynamically linked against
    * a middleware which doesn't support message loaning in which case the allocator will be used.
    *
-   * \param pub rclcpp::Publisher instance to which the memory belongs
-   * \param allocator Allocator instance in case middleware can not allocate messages
+   * \param[in] pub rclcpp::Publisher instance to which the memory belongs
+   * \param[in] allocator Allocator instance in case middleware can not allocate messages
+   * \throws anything rclcpp::exceptions::throw_from_rcl_error can throw.
    */
+  [[
+    deprecated("used the LoanedMessage constructor that does not use a shared_ptr to the allocator")
+  ]]
   LoanedMessage(
     const rclcpp::PublisherBase * pub,
     std::shared_ptr<std::allocator<MessageT>> allocator)
@@ -112,7 +117,9 @@ public:
   : pub_(std::move(other.pub_)),
     message_(std::move(other.message_)),
     message_allocator_(std::move(other.message_allocator_))
-  {}
+  {
+    other.message_ = nullptr;
+  }
 
   /// Destructor of the LoanedMessage class.
   /**
@@ -137,7 +144,7 @@ public:
     if (pub_.can_loan_messages()) {
       // return allocated memory to the middleware
       auto ret =
-        rcl_return_loaned_message_from_publisher(pub_.get_publisher_handle(), message_);
+        rcl_return_loaned_message_from_publisher(pub_.get_publisher_handle().get(), message_);
       if (ret != RCL_RET_OK) {
         RCLCPP_ERROR(
           error_logger, "rcl_deallocate_loaned_message failed: %s", rcl_get_error_string().str);
@@ -181,14 +188,30 @@ public:
   /**
    * A call to `release()` will unmanage the memory for the ROS message.
    * That means that the destructor of this class will not free the memory on scope exit.
+   * If the message is loaned from the middleware but not be published, the user needs to call
+   * `rcl_return_loaned_message_from_publisher` manually.
+   * If the memory is from the local allocator, the memory is freed when the unique pointer
+   * goes out instead.
    *
-   * \return Raw pointer to the message instance.
+   * \return std::unique_ptr to the message instance.
    */
-  MessageT * release()
+  std::unique_ptr<MessageT, std::function<void(MessageT *)>>
+  release()
   {
     auto msg = message_;
     message_ = nullptr;
-    return msg;
+
+    if (pub_.can_loan_messages()) {
+      return std::unique_ptr<MessageT, std::function<void(MessageT *)>>(msg, [](MessageT *) {});
+    }
+
+    return std::unique_ptr<MessageT, std::function<void(MessageT *)>>(
+      msg,
+      [allocator = message_allocator_](MessageT * msg_ptr) mutable {
+        // call destructor before deallocating
+        msg_ptr->~MessageT();
+        allocator.deallocate(msg_ptr, 1);
+      });
   }
 
 protected:

rclcpp/include/rclcpp/logger.hpp

@@ -21,6 +21,8 @@
 #include "rclcpp/visibility_control.hpp"
 
 #include "rcl/node.h"
+#include "rcutils/logging.h"
+#include "rcpputils/filesystem_helper.hpp"
 
 /**
  * \def RCLCPP_LOGGING_ENABLED
@@ -74,8 +76,32 @@ RCLCPP_PUBLIC
 Logger
 get_node_logger(const rcl_node_t * node);
 
+/// Get the current logging directory.
+/**
+ * For more details of how the logging directory is determined,
+ * see rcl_logging_get_logging_directory().
+ *
+ * \returns the logging directory being used.
+ * \throws rclcpp::exceptions::RCLError if an unexpected error occurs.
+ */
+RCLCPP_PUBLIC
+rcpputils::fs::path
+get_logging_directory();
+
 class Logger
 {
+public:
+  /// An enum for the type of logger level.
+  enum class Level
+  {
+    Unset = RCUTILS_LOG_SEVERITY_UNSET,  ///< The unset log level
+    Debug = RCUTILS_LOG_SEVERITY_DEBUG,  ///< The debug log level
+    Info = RCUTILS_LOG_SEVERITY_INFO,    ///< The info log level
+    Warn = RCUTILS_LOG_SEVERITY_WARN,    ///< The warn log level
+    Error = RCUTILS_LOG_SEVERITY_ERROR,  ///< The error log level
+    Fatal = RCUTILS_LOG_SEVERITY_FATAL,  ///< The fatal log level
+  };
+
 private:
   friend Logger rclcpp::get_logger(const std::string & name);
   friend ::rclcpp::node_interfaces::NodeLogging;
@@ -138,6 +164,16 @@ public:
     }
     return Logger(*name_ + "." + suffix);
   }
+
+  /// Set level for current logger.
+  /**
+   * \param[in] level the logger's level
+   * \throws rclcpp::exceptions::RCLInvalidArgument if level is invalid.
+   * \throws rclcpp::exceptions::RCLError if other error happens.
+   */
+  RCLCPP_PUBLIC
+  void
+  set_level(Level level);
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/memory_strategies.hpp

@@ -23,6 +23,10 @@ namespace rclcpp
 namespace memory_strategies
 {
 
+/// Create a MemoryStrategy sharedPtr
+/**
+ * \return a MemoryStrategy sharedPtr
+ */
 RCLCPP_PUBLIC
 memory_strategy::MemoryStrategy::SharedPtr
 create_default_strategy();

rclcpp/include/rclcpp/memory_strategy.hpp

@@ -16,6 +16,7 @@
 #define RCLCPP__MEMORY_STRATEGY_HPP_
 
 #include <list>
+#include <map>
 #include <memory>
 
 #include "rcl/allocator.h"
@@ -42,11 +43,13 @@ class RCLCPP_PUBLIC MemoryStrategy
 {
 public:
   RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(MemoryStrategy)
-  using WeakNodeList = std::list<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr>;
+  using WeakCallbackGroupsToNodesMap = std::map<rclcpp::CallbackGroup::WeakPtr,
+      rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
+      std::owner_less<rclcpp::CallbackGroup::WeakPtr>>;
 
   virtual ~MemoryStrategy() = default;
 
-  virtual bool collect_entities(const WeakNodeList & weak_nodes) = 0;
+  virtual bool collect_entities(const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual size_t number_of_ready_subscriptions() const = 0;
   virtual size_t number_of_ready_services() const = 0;
@@ -61,87 +64,89 @@ public:
   virtual void clear_handles() = 0;
   virtual void remove_null_handles(rcl_wait_set_t * wait_set) = 0;
 
-  virtual void add_guard_condition(const rcl_guard_condition_t * guard_condition) = 0;
+  virtual void
+  add_guard_condition(const rclcpp::GuardCondition & guard_condition) = 0;
 
-  virtual void remove_guard_condition(const rcl_guard_condition_t * guard_condition) = 0;
+  virtual void
+  remove_guard_condition(const rclcpp::GuardCondition * guard_condition) = 0;
 
   virtual void
   get_next_subscription(
     rclcpp::AnyExecutable & any_exec,
-    const WeakNodeList & weak_nodes) = 0;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual void
   get_next_service(
     rclcpp::AnyExecutable & any_exec,
-    const WeakNodeList & weak_nodes) = 0;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual void
   get_next_client(
     rclcpp::AnyExecutable & any_exec,
-    const WeakNodeList & weak_nodes) = 0;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual void
   get_next_timer(
     rclcpp::AnyExecutable & any_exec,
-    const WeakNodeList & weak_nodes) = 0;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual void
   get_next_waitable(
     rclcpp::AnyExecutable & any_exec,
-    const WeakNodeList & weak_nodes) = 0;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) = 0;
 
   virtual rcl_allocator_t
   get_allocator() = 0;
 
   static rclcpp::SubscriptionBase::SharedPtr
   get_subscription_by_handle(
-    std::shared_ptr<const rcl_subscription_t> subscriber_handle,
-    const WeakNodeList & weak_nodes);
+    const std::shared_ptr<const rcl_subscription_t> & subscriber_handle,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::ServiceBase::SharedPtr
   get_service_by_handle(
-    std::shared_ptr<const rcl_service_t> service_handle,
-    const WeakNodeList & weak_nodes);
+    const std::shared_ptr<const rcl_service_t> & service_handle,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::ClientBase::SharedPtr
   get_client_by_handle(
-    std::shared_ptr<const rcl_client_t> client_handle,
-    const WeakNodeList & weak_nodes);
+    const std::shared_ptr<const rcl_client_t> & client_handle,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::TimerBase::SharedPtr
   get_timer_by_handle(
-    std::shared_ptr<const rcl_timer_t> timer_handle,
-    const WeakNodeList & weak_nodes);
+    const std::shared_ptr<const rcl_timer_t> & timer_handle,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::node_interfaces::NodeBaseInterface::SharedPtr
   get_node_by_group(
-    rclcpp::CallbackGroup::SharedPtr group,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::CallbackGroup::SharedPtr & group,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::CallbackGroup::SharedPtr
   get_group_by_subscription(
-    rclcpp::SubscriptionBase::SharedPtr subscription,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::SubscriptionBase::SharedPtr & subscription,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::CallbackGroup::SharedPtr
   get_group_by_service(
-    rclcpp::ServiceBase::SharedPtr service,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::ServiceBase::SharedPtr & service,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::CallbackGroup::SharedPtr
   get_group_by_client(
-    rclcpp::ClientBase::SharedPtr client,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::ClientBase::SharedPtr & client,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::CallbackGroup::SharedPtr
   get_group_by_timer(
-    rclcpp::TimerBase::SharedPtr timer,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::TimerBase::SharedPtr & timer,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   static rclcpp::CallbackGroup::SharedPtr
   get_group_by_waitable(
-    rclcpp::Waitable::SharedPtr waitable,
-    const WeakNodeList & weak_nodes);
+    const rclcpp::Waitable::SharedPtr & waitable,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 };
 
 }  // namespace memory_strategy

rclcpp/include/rclcpp/message_info.hpp

@@ -30,6 +30,9 @@ public:
   MessageInfo() = default;
 
   /// Conversion constructor, which is intentionally not marked as explicit.
+  /**
+   * \param[in] rmw_message_info message info to initialize the class
+   */
   // cppcheck-suppress noExplicitConstructor
   MessageInfo(const rmw_message_info_t & rmw_message_info);  // NOLINT(runtime/explicit)
 

rclcpp/include/rclcpp/message_memory_strategy.hpp

@@ -23,6 +23,7 @@
 #include "rclcpp/allocator/allocator_common.hpp"
 #include "rclcpp/exceptions.hpp"
 #include "rclcpp/macros.hpp"
+#include "rclcpp/serialized_message.hpp"
 #include "rclcpp/visibility_control.hpp"
 
 #include "rcutils/logging_macros.h"
@@ -46,10 +47,10 @@ public:
   using MessageAlloc = typename MessageAllocTraits::allocator_type;
   using MessageDeleter = allocator::Deleter<MessageAlloc, MessageT>;
 
-  using SerializedMessageAllocTraits = allocator::AllocRebind<rcl_serialized_message_t, Alloc>;
+  using SerializedMessageAllocTraits = allocator::AllocRebind<rclcpp::SerializedMessage, Alloc>;
   using SerializedMessageAlloc = typename SerializedMessageAllocTraits::allocator_type;
   using SerializedMessageDeleter =
-    allocator::Deleter<SerializedMessageAlloc, rcl_serialized_message_t>;
+    allocator::Deleter<SerializedMessageAlloc, rclcpp::SerializedMessage>;
 
   using BufferAllocTraits = allocator::AllocRebind<char, Alloc>;
   using BufferAlloc = typename BufferAllocTraits::allocator_type;
@@ -86,31 +87,12 @@ public:
     return std::allocate_shared<MessageT, MessageAlloc>(*message_allocator_.get());
   }
 
-  virtual std::shared_ptr<rcl_serialized_message_t> borrow_serialized_message(size_t capacity)
+  virtual std::shared_ptr<rclcpp::SerializedMessage> borrow_serialized_message(size_t capacity)
   {
-    auto msg = new rcl_serialized_message_t;
-    *msg = rmw_get_zero_initialized_serialized_message();
-    auto ret = rmw_serialized_message_init(msg, capacity, &rcutils_allocator_);
-    if (ret != RCL_RET_OK) {
-      rclcpp::exceptions::throw_from_rcl_error(ret);
-    }
-
-    auto serialized_msg = std::shared_ptr<rcl_serialized_message_t>(
-      msg,
-      [](rmw_serialized_message_t * msg) {
-        auto fini_ret = rmw_serialized_message_fini(msg);
-        delete msg;
-        if (fini_ret != RCL_RET_OK) {
-          RCUTILS_LOG_ERROR_NAMED(
-            "rclcpp",
-            "failed to destroy serialized message: %s", rcl_get_error_string().str);
-        }
-      });
-
-    return serialized_msg;
+    return std::make_shared<rclcpp::SerializedMessage>(capacity);
   }
 
-  virtual std::shared_ptr<rcl_serialized_message_t> borrow_serialized_message()
+  virtual std::shared_ptr<rclcpp::SerializedMessage> borrow_serialized_message()
   {
     return borrow_serialized_message(default_buffer_capacity_);
   }
@@ -127,7 +109,8 @@ public:
     msg.reset();
   }
 
-  virtual void return_serialized_message(std::shared_ptr<rcl_serialized_message_t> & serialized_msg)
+  virtual void return_serialized_message(
+    std::shared_ptr<rclcpp::SerializedMessage> & serialized_msg)
   {
     serialized_msg.reset();
   }

rclcpp/include/rclcpp/network_flow_endpoint.hpp

@@ -0,0 +1,115 @@
+// Copyright 2020 Ericsson AB
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__NETWORK_FLOW_ENDPOINT_HPP_
+#define RCLCPP__NETWORK_FLOW_ENDPOINT_HPP_
+
+#include <cstdint>
+#include <string>
+#include <iostream>
+
+#include "rcl/network_flow_endpoints.h"
+
+#include "rclcpp/visibility_control.hpp"
+
+namespace rclcpp
+{
+
+/// Forward declaration
+class NetworkFlowEndpoint;
+
+/// Check if two NetworkFlowEndpoint instances are equal
+RCLCPP_PUBLIC
+bool operator==(const NetworkFlowEndpoint & left, const NetworkFlowEndpoint & right);
+
+/// Check if two NetworkFlowEndpoint instances are not equal
+RCLCPP_PUBLIC
+bool operator!=(const NetworkFlowEndpoint & left, const NetworkFlowEndpoint & right);
+
+/// Streaming helper for NetworkFlowEndpoint
+RCLCPP_PUBLIC
+std::ostream & operator<<(std::ostream & os, const NetworkFlowEndpoint & network_flow_endpoint);
+
+/**
+ * Class describes a network flow endpoint based on the counterpart definition
+ * in the RMW layer.
+ */
+class NetworkFlowEndpoint
+{
+public:
+  /// Construct from rcl_network_flow_endpoint_t
+  RCLCPP_PUBLIC
+  explicit NetworkFlowEndpoint(const rcl_network_flow_endpoint_t & network_flow_endpoint)
+  : transport_protocol_(
+      rcl_network_flow_endpoint_get_transport_protocol_string(network_flow_endpoint.
+      transport_protocol)),
+    internet_protocol_(
+      rcl_network_flow_endpoint_get_internet_protocol_string(
+        network_flow_endpoint.internet_protocol)),
+    transport_port_(network_flow_endpoint.transport_port),
+    flow_label_(network_flow_endpoint.flow_label),
+    dscp_(network_flow_endpoint.dscp),
+    internet_address_(network_flow_endpoint.internet_address)
+  {
+  }
+
+  /// Get transport protocol
+  RCLCPP_PUBLIC
+  const std::string & transport_protocol() const;
+
+  /// Get internet protocol
+  RCLCPP_PUBLIC
+  const std::string & internet_protocol() const;
+
+  /// Get transport port
+  RCLCPP_PUBLIC
+  uint16_t transport_port() const;
+
+  /// Get flow label
+  RCLCPP_PUBLIC
+  uint32_t flow_label() const;
+
+  /// Get DSCP
+  RCLCPP_PUBLIC
+  uint8_t dscp() const;
+
+  /// Get internet address
+  RCLCPP_PUBLIC
+  const std::string & internet_address() const;
+
+  /// Compare two NetworkFlowEndpoint instances
+  friend bool rclcpp::operator==(
+    const NetworkFlowEndpoint & left,
+    const NetworkFlowEndpoint & right);
+  friend bool rclcpp::operator!=(
+    const NetworkFlowEndpoint & left,
+    const NetworkFlowEndpoint & right);
+
+  /// Streaming helper
+  friend std::ostream & rclcpp::operator<<(
+    std::ostream & os,
+    const NetworkFlowEndpoint & network_flow_endpoint);
+
+private:
+  std::string transport_protocol_;
+  std::string internet_protocol_;
+  uint16_t transport_port_;
+  uint32_t flow_label_;
+  uint8_t dscp_;
+  std::string internet_address_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__NETWORK_FLOW_ENDPOINT_HPP_

rclcpp/include/rclcpp/node.hpp

@@ -17,6 +17,7 @@
 
 #include <atomic>
 #include <condition_variable>
+#include <functional>
 #include <list>
 #include <map>
 #include <memory>
@@ -26,6 +27,8 @@
 #include <utility>
 #include <vector>
 
+#include "rcutils/macros.h"
+
 #include "rcl/error_handling.h"
 #include "rcl/node.h"
 
@@ -39,6 +42,8 @@
 #include "rclcpp/clock.hpp"
 #include "rclcpp/context.hpp"
 #include "rclcpp/event.hpp"
+#include "rclcpp/generic_publisher.hpp"
+#include "rclcpp/generic_subscription.hpp"
 #include "rclcpp/logger.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/message_memory_strategy.hpp"
@@ -78,6 +83,7 @@ public:
   /**
    * \param[in] node_name Name of the node.
    * \param[in] options Additional options to control creation of the node.
+   * \throws InvalidNamespaceError if the namespace is invalid
    */
   RCLCPP_PUBLIC
   explicit Node(
@@ -89,6 +95,7 @@ public:
    * \param[in] node_name Name of the node.
    * \param[in] namespace_ Namespace of the node.
    * \param[in] options Additional options to control creation of the node.
+   * \throws InvalidNamespaceError if the namespace is invalid
    */
   RCLCPP_PUBLIC
   explicit Node(
@@ -122,6 +129,7 @@ public:
   /// Get the fully-qualified name of the node.
   /**
    * The fully-qualified name includes the local namespace and name of the node.
+   * \return fully-qualified name of the node.
    */
   RCLCPP_PUBLIC
   const char *
@@ -136,12 +144,20 @@ public:
   /// Create and return a callback group.
   RCLCPP_PUBLIC
   rclcpp::CallbackGroup::SharedPtr
-  create_callback_group(rclcpp::CallbackGroupType group_type);
+  create_callback_group(
+    rclcpp::CallbackGroupType group_type,
+    bool automatically_add_to_executor_with_node = true);
 
-  /// Return the list of callback groups in the node.
+  /// Iterate over the callback groups in the node, calling the given function on each valid one.
+  /**
+   * This method is called in a thread-safe way, and also makes sure to only call the given
+   * function on those items that are still valid.
+   *
+   * \param[in] func The callback function to call on each valid callback group.
+   */
   RCLCPP_PUBLIC
-  const std::vector<rclcpp::CallbackGroup::WeakPtr> &
-  get_callback_groups() const;
+  void
+  for_each_callback_group(const node_interfaces::NodeBaseInterface::CallbackGroupFunction & func);
 
   /// Create and return a Publisher.
   /**
@@ -156,7 +172,7 @@ public:
    * pub = node->create_publisher<MsgT>("chatter", QoS(10));  // implicitly KeepLast
    * pub = node->create_publisher<MsgT>("chatter", QoS(KeepLast(10)));
    * pub = node->create_publisher<MsgT>("chatter", QoS(KeepAll()));
-   * pub = node->create_publisher<MsgT>("chatter", QoS(1).best_effort().volatile());
+   * pub = node->create_publisher<MsgT>("chatter", QoS(1).best_effort().durability_volatile());
    * {
    *   rclcpp::QoS custom_qos(KeepLast(10), rmw_qos_profile_sensor_data);
    *   pub = node->create_publisher<MsgT>("chatter", custom_qos);
@@ -186,8 +202,8 @@ public:
   /// Create and return a Subscription.
   /**
    * \param[in] topic_name The topic to subscribe on.
+   * \param[in] qos QoS profile for Subcription.
    * \param[in] callback The user-defined callback function to receive a message
-   * \param[in] qos_history_depth The depth of the subscription's incoming message queue.
    * \param[in] options Additional options for the creation of the Subscription.
    * \param[in] msg_mem_strat The message memory strategy to use for allocating messages.
    * \return Shared pointer to the created subscription.
@@ -196,13 +212,8 @@ public:
     typename MessageT,
     typename CallbackT,
     typename AllocatorT = std::allocator<void>,
-    typename CallbackMessageT =
-    typename rclcpp::subscription_traits::has_message_type<CallbackT>::type,
-    typename SubscriptionT = rclcpp::Subscription<CallbackMessageT, AllocatorT>,
-    typename MessageMemoryStrategyT = rclcpp::message_memory_strategy::MessageMemoryStrategy<
-      CallbackMessageT,
-      AllocatorT
-    >
+    typename SubscriptionT = rclcpp::Subscription<MessageT, AllocatorT>,
+    typename MessageMemoryStrategyT = typename SubscriptionT::MessageMemoryStrategyType
   >
   std::shared_ptr<SubscriptionT>
   create_subscription(
@@ -229,7 +240,13 @@ public:
     CallbackT callback,
     rclcpp::CallbackGroup::SharedPtr group = nullptr);
 
-  /* Create and return a Client. */
+  /// Create and return a Client.
+  /**
+   * \param[in] service_name The topic to service on.
+   * \param[in] qos_profile rmw_qos_profile_t Quality of service profile for client.
+   * \param[in] group Callback group to call the service.
+   * \return Shared pointer to the created client.
+   */
   template<typename ServiceT>
   typename rclcpp::Client<ServiceT>::SharedPtr
   create_client(
@@ -237,7 +254,14 @@ public:
     const rmw_qos_profile_t & qos_profile = rmw_qos_profile_services_default,
     rclcpp::CallbackGroup::SharedPtr group = nullptr);
 
-  /* Create and return a Service. */
+  /// Create and return a Service.
+  /**
+   * \param[in] service_name The topic to service on.
+   * \param[in] callback User-defined callback function.
+   * \param[in] qos_profile rmw_qos_profile_t Quality of service profile for client.
+   * \param[in] group Callback group to call the service.
+   * \return Shared pointer to the created service.
+   */
   template<typename ServiceT, typename CallbackT>
   typename rclcpp::Service<ServiceT>::SharedPtr
   create_service(
@@ -246,6 +270,55 @@ public:
     const rmw_qos_profile_t & qos_profile = rmw_qos_profile_services_default,
     rclcpp::CallbackGroup::SharedPtr group = nullptr);
 
+  /// Create and return a GenericPublisher.
+  /**
+   * The returned pointer will never be empty, but this function can throw various exceptions, for
+   * instance when the message's package can not be found on the AMENT_PREFIX_PATH.
+   *
+   * \param[in] topic_name Topic name
+   * \param[in] topic_type Topic type
+   * \param[in] qos %QoS settings
+   * \param options %Publisher options.
+   * Not all publisher options are currently respected, the only relevant options for this
+   * publisher are `event_callbacks`, `use_default_callbacks`, and `%callback_group`.
+   * \return Shared pointer to the created generic publisher.
+   */
+  template<typename AllocatorT = std::allocator<void>>
+  std::shared_ptr<rclcpp::GenericPublisher> create_generic_publisher(
+    const std::string & topic_name,
+    const std::string & topic_type,
+    const rclcpp::QoS & qos,
+    const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options = (
+      rclcpp::PublisherOptionsWithAllocator<AllocatorT>()
+    )
+  );
+
+  /// Create and return a GenericSubscription.
+  /**
+   * The returned pointer will never be empty, but this function can throw various exceptions, for
+   * instance when the message's package can not be found on the AMENT_PREFIX_PATH.
+   *
+   * \param[in] topic_name Topic name
+   * \param[in] topic_type Topic type
+   * \param[in] qos %QoS settings
+   * \param[in] callback Callback for new messages of serialized form
+   * \param[in] options %Subscription options.
+   * Not all subscription options are currently respected, the only relevant options for this
+ * subscription are `event_callbacks`, `use_default_callbacks`, `ignore_local_publications`, and
+ * `%callback_group`.
+   * \return Shared pointer to the created generic subscription.
+   */
+  template<typename AllocatorT = std::allocator<void>>
+  std::shared_ptr<rclcpp::GenericSubscription> create_generic_subscription(
+    const std::string & topic_name,
+    const std::string & topic_type,
+    const rclcpp::QoS & qos,
+    std::function<void(std::shared_ptr<rclcpp::SerializedMessage>)> callback,
+    const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options = (
+      rclcpp::SubscriptionOptionsWithAllocator<AllocatorT>()
+    )
+  );
+
   /// Declare and initialize a parameter, return the effective value.
   /**
    * This method is used to declare that a parameter exists on this node.
@@ -264,7 +337,7 @@ public:
    * If `ignore_override` is `true`, the parameter override will be ignored.
    *
    * This method, if successful, will result in any callback registered with
-   * set_on_parameters_set_callback to be called.
+   * add_on_set_parameters_callback to be called.
    * If that callback prevents the initial value for the parameter from being
    * set then rclcpp::exceptions::InvalidParameterValueException is thrown.
    *
@@ -285,16 +358,43 @@ public:
    *   name is invalid.
    * \throws rclcpp::exceptions::InvalidParameterValueException if initial
    *   value fails to be set.
+   * \throws rclcpp::exceptions::InvalidParameterTypeException
+   *   if the type of the default value or override is wrong.
    */
   RCLCPP_PUBLIC
   const rclcpp::ParameterValue &
   declare_parameter(
     const std::string & name,
-    const rclcpp::ParameterValue & default_value = rclcpp::ParameterValue(),
+    const rclcpp::ParameterValue & default_value,
     const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
     rcl_interfaces::msg::ParameterDescriptor(),
     bool ignore_override = false);
 
+  /// Declare and initialize a parameter, return the effective value.
+  /**
+   * Same as the previous one, but a default value is not provided and the user
+   * must provide a parameter override of the correct type.
+   *
+   * \param[in] name The name of the parameter.
+   * \param[in] type Desired type of the parameter, which will enforced at runtime.
+   * \param[in] parameter_descriptor An optional, custom description for
+   *   the parameter.
+   * \param[in] ignore_override When `true`, the parameter override is ignored.
+   *    Default to `false`.
+   * \return A const reference to the value of the parameter.
+   * \throws Same as the previous overload taking a default value.
+   * \throws rclcpp::exceptions::InvalidParameterTypeException
+   *   if an override is not provided or the provided override is of the wrong type.
+   */
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
+    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor{},
+    bool ignore_override = false);
+
   /// Declare and initialize a parameter with a type.
   /**
    * See the non-templated declare_parameter() on this class for details.
@@ -325,6 +425,18 @@ public:
     rcl_interfaces::msg::ParameterDescriptor(),
     bool ignore_override = false);
 
+  /// Declare and initialize a parameter with a type.
+  /**
+   * See the non-templated declare_parameter() on this class for details.
+   */
+  template<typename ParameterT>
+  auto
+  declare_parameter(
+    const std::string & name,
+    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor(),
+    bool ignore_override = false);
+
   /// Declare and initialize several parameters with the same namespace and type.
   /**
    * For each key in the map, a parameter with a name of "namespace.key"
@@ -346,7 +458,7 @@ public:
    * by the function call will be ignored.
    *
    * This method, if successful, will result in any callback registered with
-   * set_on_parameters_set_callback to be called, once for each parameter.
+   * add_on_set_parameters_callback to be called, once for each parameter.
    * If that callback prevents the initial value for any parameter from being
    * set then rclcpp::exceptions::InvalidParameterValueException is thrown.
    *
@@ -388,7 +500,7 @@ public:
   /// Undeclare a previously declared parameter.
   /**
    * This method will not cause a callback registered with
-   * set_on_parameters_set_callback to be called.
+   * add_on_set_parameters_callback to be called.
    *
    * \param[in] name The name of the parameter to be undeclared.
    * \throws rclcpp::exceptions::ParameterNotDeclaredException if the parameter
@@ -422,7 +534,7 @@ public:
    * Parameter overrides are ignored by set_parameter.
    *
    * This method will result in any callback registered with
-   * set_on_parameters_set_callback to be called.
+   * add_on_set_parameters_callback to be called.
    * If the callback prevents the parameter from being set, then it will be
    * reflected in the SetParametersResult that is returned, but no exception
    * will be thrown.
@@ -463,7 +575,7 @@ public:
    * corresponding SetParametersResult in the vector returned by this function.
    *
    * This method will result in any callback registered with
-   * set_on_parameters_set_callback to be called, once for each parameter.
+   * add_on_set_parameters_callback to be called, once for each parameter.
    * If the callback prevents the parameter from being set, then, as mentioned
    * before, it will be reflected in the corresponding SetParametersResult
    * that is returned, but no exception will be thrown.
@@ -494,7 +606,7 @@ public:
    * If the exception is thrown then none of the parameters will have been set.
    *
    * This method will result in any callback registered with
-   * set_on_parameters_set_callback to be called, just one time.
+   * add_on_set_parameters_callback to be called, just one time.
    * If the callback prevents the parameters from being set, then it will be
    * reflected in the SetParametersResult which is returned, but no exception
    * will be thrown.
@@ -592,6 +704,24 @@ public:
     ParameterT & parameter,
     const ParameterT & alternative_value) const;
 
+  /// Return the parameter value, or the "alternative_value" if not set.
+  /**
+   * If the parameter was not set, then the "alternative_value" argument is returned.
+   *
+   * This method will not throw the rclcpp::exceptions::ParameterNotDeclaredException exception.
+   *
+   * In all cases, the parameter is never set or declared within the node.
+   *
+   * \param[in] name The name of the parameter to get.
+   * \param[in] alternative_value Value to be stored in output if the parameter was not set.
+   * \returns The value of the parameter.
+   */
+  template<typename ParameterT>
+  ParameterT
+  get_parameter_or(
+    const std::string & name,
+    const ParameterT & alternative_value) const;
+
   /// Return the parameters by the given parameter names.
   /**
    * Like get_parameters(), this method may throw the
@@ -672,6 +802,7 @@ public:
    * \throws rclcpp::exceptions::ParameterNotDeclaredException if the
    *   parameter has not been declared and undeclared parameters are not
    *   allowed.
+   * \throws std::runtime_error if the number of described parameters is more than one
    */
   RCLCPP_PUBLIC
   rcl_interfaces::msg::ParameterDescriptor
@@ -694,6 +825,7 @@ public:
    * \throws rclcpp::exceptions::ParameterNotDeclaredException if any of the
    *   parameters have not been declared and undeclared parameters are not
    *   allowed.
+   * \throws std::runtime_error if the number of described parameters is more than one
    */
   RCLCPP_PUBLIC
   std::vector<rcl_interfaces::msg::ParameterDescriptor>
@@ -763,6 +895,9 @@ public:
    *
    * This allows the node developer to control which parameters may be changed.
    *
+   * It is considered bad practice to reject changes for "unknown" parameters as this prevents
+   * other parts of the node (that may be aware of these parameters) from handling them.
+   *
    * Note that the callback is called when declare_parameter() and its variants
    * are called, and so you cannot assume the parameter has been set before
    * this callback, so when checking a new value against the existing one, you
@@ -774,7 +909,7 @@ public:
    * of the {get,list,describe}_parameter() methods), but may *not* modify
    * other parameters (by calling any of the {set,declare}_parameter() methods)
    * or modify the registered callback itself (by calling the
-   * set_on_parameters_set_callback() method).  If a callback tries to do any
+   * add_on_set_parameters_callback() method).  If a callback tries to do any
    * of the latter things,
    * rclcpp::exceptions::ParameterModifiedInCallbackException will be thrown.
    *
@@ -794,6 +929,7 @@ public:
    * \throws std::bad_alloc if the allocation of the OnSetParametersCallbackHandle fails.
    */
   RCLCPP_PUBLIC
+  RCUTILS_WARN_UNUSED
   OnSetParametersCallbackHandle::SharedPtr
   add_on_set_parameters_callback(OnParametersSetCallbackType callback);
 
@@ -824,24 +960,6 @@ public:
   void
   remove_on_set_parameters_callback(const OnSetParametersCallbackHandle * const handler);
 
-  /// Register a callback to be called anytime a parameter is about to be changed.
-  /**
-   * With this method, only one callback can be set at a time. The callback that was previously
-   * set by this method is returned or `nullptr` if no callback was previously set.
-   *
-   * The callbacks added with `add_on_set_parameters_callback` are stored in a different place.
-   * `remove_on_set_parameters_callback` can't be used with the callbacks registered with this
-   * method. For removing it, use `set_on_parameters_set_callback(nullptr)`.
-   *
-   * \param[in] callback The callback to be called when the value for a
-   *   parameter is about to be set.
-   * \return The previous callback that was registered, if there was one,
-   *   otherwise nullptr.
-   */
-  RCLCPP_PUBLIC
-  OnParametersSetCallbackType
-  set_on_parameters_set_callback(rclcpp::Node::OnParametersSetCallbackType callback);
-
   /// Get the fully-qualified names of all available nodes.
   /**
    * The fully-qualified name includes the local namespace and name of the node.
@@ -851,18 +969,56 @@ public:
   std::vector<std::string>
   get_node_names() const;
 
+  /// Return a map of existing topic names to list of topic types.
+  /**
+   * \return a map of existing topic names to list of topic types.
+   * \throws std::runtime_error anything that rcl_error can throw
+   */
   RCLCPP_PUBLIC
   std::map<std::string, std::vector<std::string>>
   get_topic_names_and_types() const;
 
+  /// Return a map of existing service names to list of service types.
+  /**
+   * \return a map of existing service names to list of service types.
+   * \throws std::runtime_error anything that rcl_error can throw
+   */
   RCLCPP_PUBLIC
   std::map<std::string, std::vector<std::string>>
   get_service_names_and_types() const;
 
+  /// Return a map of existing service names to list of service types for a specific node.
+  /**
+   * This function only considers services - not clients.
+   * The returned names are the actual names used and do not have remap rules applied.
+   *
+   * \param[in] node_name name of the node.
+   * \param[in] namespace_ namespace of the node.
+   * \return a map of existing service names to list of service types.
+   * \throws std::runtime_error anything that rcl_error can throw.
+   */
+  RCLCPP_PUBLIC
+  std::map<std::string, std::vector<std::string>>
+  get_service_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_) const;
+
+  /// Return the number of publishers created for a given topic.
+  /**
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   * \return number of publishers that have been created for the given topic.
+   * \throws std::runtime_error if publishers could not be counted
+   */
   RCLCPP_PUBLIC
   size_t
   count_publishers(const std::string & topic_name) const;
 
+  /// Return the number of subscribers created for a given topic.
+  /**
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   * \return number of subscribers that have been created for the given topic.
+   * \throws std::runtime_error if subscribers could not be counted
+   */
   RCLCPP_PUBLIC
   size_t
   count_subscribers(const std::string & topic_name) const;
@@ -882,7 +1038,7 @@ public:
    * A relative or private topic will be expanded using this node's namespace and name.
    * The queried `topic_name` is not remapped.
    *
-   * \param[in] topic_name the topic_name on which to find the publishers.
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
    * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
    *   otherwise it should be a valid ROS topic name. Defaults to `false`.
    * \return a list of TopicEndpointInfo representing all the publishers on this topic.
@@ -908,7 +1064,7 @@ public:
    * A relative or private topic will be expanded using this node's namespace and name.
    * The queried `topic_name` is not remapped.
    *
-   * \param[in] topic_name the topic_name on which to find the subscriptions.
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
    * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
    *   otherwise it should be a valid ROS topic name. Defaults to `false`.
    * \return a list of TopicEndpointInfo representing all the subscriptions on this topic.
@@ -932,6 +1088,9 @@ public:
   /**
    * The given Event must be acquire through the get_graph_event() method.
    *
+   * \param[in] event pointer to an Event to wait for
+   * \param[in] timeout nanoseconds to wait for the Event to change the state
+   *
    * \throws InvalidEventError if the given event is nullptr
    * \throws EventNotRegisteredError if the given event was not acquired with
    *   get_graph_event().
@@ -942,14 +1101,26 @@ public:
     rclcpp::Event::SharedPtr event,
     std::chrono::nanoseconds timeout);
 
+  /// Get a clock as a non-const shared pointer which is managed by the node.
+  /**
+   * \sa rclcpp::node_interfaces::NodeClock::get_clock
+   */
   RCLCPP_PUBLIC
   rclcpp::Clock::SharedPtr
   get_clock();
 
+  /// Get a clock as a const shared pointer which is managed by the node.
+  /**
+   * \sa rclcpp::node_interfaces::NodeClock::get_clock
+   */
   RCLCPP_PUBLIC
   rclcpp::Clock::ConstSharedPtr
   get_clock() const;
 
+  /// Returns current time from the time source specified by clock_type.
+  /**
+   * \sa rclcpp::Clock::now
+   */
   RCLCPP_PUBLIC
   Time
   now() const;
@@ -999,7 +1170,7 @@ public:
   rclcpp::node_interfaces::NodeParametersInterface::SharedPtr
   get_node_parameters_interface();
 
-  /// Return the Node's internal NodeParametersInterface implementation.
+  /// Return the Node's internal NodeTimeSourceInterface implementation.
   RCLCPP_PUBLIC
   rclcpp::node_interfaces::NodeTimeSourceInterface::SharedPtr
   get_node_time_source_interface();
@@ -1111,19 +1282,6 @@ public:
   const rclcpp::NodeOptions &
   get_node_options() const;
 
-  /// Manually assert that this Node is alive (for RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_NODE).
-  /**
-   * If the rmw Liveliness policy is set to RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_NODE, the creator
-   * of this node may manually call `assert_liveliness` at some point in time to signal to the rest
-   * of the system that this Node is still alive.
-   *
-   * \return `true` if the liveliness was asserted successfully, otherwise `false`
-   */
-  RCLCPP_PUBLIC
-  RCUTILS_WARN_UNUSED
-  bool
-  assert_liveliness() const;
-
 protected:
   /// Construct a sub-node, which will extend the namespace of all entities created with it.
   /**
@@ -1140,10 +1298,6 @@ protected:
 private:
   RCLCPP_DISABLE_COPY(Node)
 
-  RCLCPP_PUBLIC
-  bool
-  group_in_node(CallbackGroup::SharedPtr group);
-
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_;
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_;
   rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_;

rclcpp/include/rclcpp/node_impl.hpp

@@ -19,6 +19,7 @@
 #include <rmw/rmw.h>
 
 #include <algorithm>
+#include <chrono>
 #include <cstdlib>
 #include <iostream>
 #include <limits>
@@ -35,12 +36,16 @@
 
 #include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/create_client.hpp"
+#include "rclcpp/create_generic_publisher.hpp"
+#include "rclcpp/create_generic_subscription.hpp"
 #include "rclcpp/create_publisher.hpp"
 #include "rclcpp/create_service.hpp"
 #include "rclcpp/create_subscription.hpp"
+#include "rclcpp/create_timer.hpp"
 #include "rclcpp/detail/resolve_enable_topic_statistics.hpp"
 #include "rclcpp/parameter.hpp"
 #include "rclcpp/qos.hpp"
+#include "rclcpp/timer.hpp"
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/visibility_control.hpp"
 
@@ -81,7 +86,6 @@ template<
   typename MessageT,
   typename CallbackT,
   typename AllocatorT,
-  typename CallbackMessageT,
   typename SubscriptionT,
   typename MessageMemoryStrategyT>
 std::shared_ptr<SubscriptionT>
@@ -108,12 +112,12 @@ Node::create_wall_timer(
   CallbackT callback,
   rclcpp::CallbackGroup::SharedPtr group)
 {
-  auto timer = rclcpp::WallTimer<CallbackT>::make_shared(
-    std::chrono::duration_cast<std::chrono::nanoseconds>(period),
+  return rclcpp::create_wall_timer(
+    period,
     std::move(callback),
-    this->node_base_->get_context());
-  node_timers_->add_timer(timer, group);
-  return timer;
+    group,
+    this->node_base_.get(),
+    this->node_timers_.get());
 }
 
 template<typename ServiceT>
@@ -149,6 +153,43 @@ Node::create_service(
     group);
 }
 
+template<typename AllocatorT>
+std::shared_ptr<rclcpp::GenericPublisher>
+Node::create_generic_publisher(
+  const std::string & topic_name,
+  const std::string & topic_type,
+  const rclcpp::QoS & qos,
+  const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options)
+{
+  return rclcpp::create_generic_publisher(
+    node_topics_,
+    extend_name_with_sub_namespace(topic_name, this->get_sub_namespace()),
+    topic_type,
+    qos,
+    options
+  );
+}
+
+template<typename AllocatorT>
+std::shared_ptr<rclcpp::GenericSubscription>
+Node::create_generic_subscription(
+  const std::string & topic_name,
+  const std::string & topic_type,
+  const rclcpp::QoS & qos,
+  std::function<void(std::shared_ptr<rclcpp::SerializedMessage>)> callback,
+  const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options)
+{
+  return rclcpp::create_generic_subscription(
+    node_topics_,
+    extend_name_with_sub_namespace(topic_name, this->get_sub_namespace()),
+    topic_type,
+    qos,
+    std::move(callback),
+    options
+  );
+}
+
+
 template<typename ParameterT>
 auto
 Node::declare_parameter(
@@ -169,6 +210,28 @@ Node::declare_parameter(
   }
 }
 
+template<typename ParameterT>
+auto
+Node::declare_parameter(
+  const std::string & name,
+  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  bool ignore_override)
+{
+  // get advantage of parameter value template magic to get
+  // the correct rclcpp::ParameterType from ParameterT
+  rclcpp::ParameterValue value{ParameterT{}};
+  try {
+    return this->declare_parameter(
+      name,
+      value.get_type(),
+      parameter_descriptor,
+      ignore_override
+    ).get<ParameterT>();
+  } catch (const ParameterTypeException &) {
+    throw exceptions::UninitializedStaticallyTypedParameterException(name);
+  }
+}
+
 template<typename ParameterT>
 std::vector<ParameterT>
 Node::declare_parameters(
@@ -250,6 +313,17 @@ Node::get_parameter_or(
   return got_parameter;
 }
 
+template<typename ParameterT>
+ParameterT
+Node::get_parameter_or(
+  const std::string & name,
+  const ParameterT & alternative_value) const
+{
+  ParameterT parameter;
+  get_parameter_or(name, parameter, alternative_value);
+  return parameter;
+}
+
 // this is a partially-specialized version of get_parameter above,
 // where our concrete type for ParameterT is std::map, but the to-be-determined
 // type is the value in the map.

rclcpp/include/rclcpp/node_interfaces/get_node_base_interface.hpp

@@ -1,149 +0,0 @@
-// Copyright 2019 Open Source Robotics Foundation, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef RCLCPP__NODE_INTERFACES__GET_NODE_BASE_INTERFACE_HPP_
-#define RCLCPP__NODE_INTERFACES__GET_NODE_BASE_INTERFACE_HPP_
-
-#include <memory>
-#include <utility>
-#include <type_traits>
-
-#include "rclcpp/node_interfaces/node_base_interface.hpp"
-
-/// This header provides the get_node_base_interface() template function.
-/**
- * This function is useful for getting the NodeBaseInterface pointer from
- * various kinds of Node-like classes.
- *
- * It's able to get the NodeBaseInterface pointer so long as the class
- * has a method called ``get_node_base_interface()`` which returns
- * either a pointer (const or not) to a NodeBaseInterface or a
- * std::shared_ptr to a NodeBaseInterface.
- */
-
-namespace rclcpp
-{
-namespace node_interfaces
-{
-
-namespace detail
-{
-
-// This is a meta-programming checker for if a given Node-like object has a
-// getter called get_node_base_interface() which returns various types,
-// e.g. const pointer or a shared pointer.
-template<typename NodeType, typename ReturnType>
-struct has_get_node_base_interface
-{
-private:
-  template<typename T>
-  static constexpr
-  auto
-  check(T *)->typename std::is_same<
-    decltype(std::declval<T>().get_node_base_interface()),
-    ReturnType
-  >::type;
-
-  template<typename>
-  static constexpr
-  std::false_type
-  check(...);
-
-public:
-  using type = decltype(check<NodeType>(nullptr));
-  static constexpr bool value = type::value;
-};
-
-// If NodeType is a pointer to NodeBaseInterface already (just normal function overload).
-inline
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface_from_pointer(rclcpp::node_interfaces::NodeBaseInterface * pointer)
-{
-  return pointer;
-}
-
-// If NodeType has a method called get_node_base_interface() which returns a shared pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_base_interface<
-    typename std::remove_pointer<NodeType>::type,
-    std::shared_ptr<rclcpp::node_interfaces::NodeBaseInterface>
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_base_interface().get();
-}
-
-// If NodeType has a method called get_node_base_interface() which returns a pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_base_interface<
-    typename std::remove_pointer<NodeType>::type,
-    rclcpp::node_interfaces::NodeBaseInterface *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_base_interface();
-}
-
-// Forward shared_ptr's to const node pointer signatures.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_same<
-    NodeType,
-    typename std::shared_ptr<typename std::remove_pointer<NodeType>::type::element_type> *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface_from_pointer(NodeType node_shared_pointer)
-{
-  return get_node_base_interface_from_pointer(node_shared_pointer->get());
-}
-
-}  // namespace detail
-
-/// Get the NodeBaseInterface as a pointer from a pointer to a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_pointer<NodeType>::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface(NodeType node_pointer)
-{
-  // Forward pointers to detail implmentation directly.
-  return detail::get_node_base_interface_from_pointer(node_pointer);
-}
-
-/// Get the NodeBaseInterface as a pointer from a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<
-    !std::is_pointer<typename std::remove_reference<NodeType>::type>::value, int
-  >::type = 0
->
-rclcpp::node_interfaces::NodeBaseInterface *
-get_node_base_interface(NodeType && node_reference)
-{
-  // Forward references to detail implmentation as a pointer.
-  return detail::get_node_base_interface_from_pointer(&node_reference);
-}
-
-}  // namespace node_interfaces
-}  // namespace rclcpp
-
-#endif  // RCLCPP__NODE_INTERFACES__GET_NODE_BASE_INTERFACE_HPP_

rclcpp/include/rclcpp/node_interfaces/get_node_timers_interface.hpp

@@ -1,149 +0,0 @@
-// Copyright 2019 Open Source Robotics Foundation, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef RCLCPP__NODE_INTERFACES__GET_NODE_TIMERS_INTERFACE_HPP_
-#define RCLCPP__NODE_INTERFACES__GET_NODE_TIMERS_INTERFACE_HPP_
-
-#include <memory>
-#include <utility>
-#include <type_traits>
-
-#include "rclcpp/node_interfaces/node_timers_interface.hpp"
-
-/// This header provides the get_node_timers_interface() template function.
-/**
- * This function is useful for getting the NodeTimersInterface pointer from
- * various kinds of Node-like classes.
- *
- * It's able to get the NodeTimersInterface pointer so long as the class
- * has a method called ``get_node_timers_interface()`` which returns
- * either a pointer (const or not) to a NodeTimersInterface or a
- * std::shared_ptr to a NodeTimersInterface.
- */
-
-namespace rclcpp
-{
-namespace node_interfaces
-{
-
-namespace detail
-{
-
-// This is a meta-programming checker for if a given Node-like object has a
-// getter called get_node_timers_interface() which returns various types,
-// e.g. const pointer or a shared pointer.
-template<typename NodeType, typename ReturnType>
-struct has_get_node_timers_interface
-{
-private:
-  template<typename T>
-  static constexpr
-  auto
-  check(T *)->typename std::is_same<
-    decltype(std::declval<T>().get_node_timers_interface()),
-    ReturnType
-  >::type;
-
-  template<typename>
-  static constexpr
-  std::false_type
-  check(...);
-
-public:
-  using type = decltype(check<NodeType>(nullptr));
-  static constexpr bool value = type::value;
-};
-
-// If NodeType is a pointer to NodeTimersInterface already (just normal function overload).
-inline
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface_from_pointer(rclcpp::node_interfaces::NodeTimersInterface * pointer)
-{
-  return pointer;
-}
-
-// If NodeType has a method called get_node_timers_interface() which returns a shared pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_timers_interface<
-    typename std::remove_pointer<NodeType>::type,
-    std::shared_ptr<rclcpp::node_interfaces::NodeTimersInterface>
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_timers_interface().get();
-}
-
-// If NodeType has a method called get_node_timers_interface() which returns a pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_timers_interface<
-    typename std::remove_pointer<NodeType>::type,
-    rclcpp::node_interfaces::NodeTimersInterface *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_timers_interface();
-}
-
-// Forward shared_ptr's to const node pointer signatures.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_same<
-    NodeType,
-    typename std::shared_ptr<typename std::remove_pointer<NodeType>::type::element_type> *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface_from_pointer(NodeType node_shared_pointer)
-{
-  return get_node_timers_interface_from_pointer(node_shared_pointer->get());
-}
-
-}  // namespace detail
-
-/// Get the NodeTimersInterface as a pointer from a pointer to a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_pointer<NodeType>::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface(NodeType node_pointer)
-{
-  // Forward pointers to detail implmentation directly.
-  return detail::get_node_timers_interface_from_pointer(node_pointer);
-}
-
-/// Get the NodeTimersInterface as a pointer from a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<
-    !std::is_pointer<typename std::remove_reference<NodeType>::type>::value, int
-  >::type = 0
->
-rclcpp::node_interfaces::NodeTimersInterface *
-get_node_timers_interface(NodeType && node_reference)
-{
-  // Forward references to detail implmentation as a pointer.
-  return detail::get_node_timers_interface_from_pointer(&node_reference);
-}
-
-}  // namespace node_interfaces
-}  // namespace rclcpp
-
-#endif  // RCLCPP__NODE_INTERFACES__GET_NODE_TIMERS_INTERFACE_HPP_

rclcpp/include/rclcpp/node_interfaces/get_node_topics_interface.hpp

@@ -1,149 +0,0 @@
-// Copyright 2019 Open Source Robotics Foundation, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef RCLCPP__NODE_INTERFACES__GET_NODE_TOPICS_INTERFACE_HPP_
-#define RCLCPP__NODE_INTERFACES__GET_NODE_TOPICS_INTERFACE_HPP_
-
-#include <memory>
-#include <utility>
-#include <type_traits>
-
-#include "rclcpp/node_interfaces/node_topics_interface.hpp"
-
-/// This header provides the get_node_topics_interface() template function.
-/**
- * This function is useful for getting the NodeTopicsInterface pointer from
- * various kinds of Node-like classes.
- *
- * It's able to get the NodeTopicsInterface pointer so long as the class
- * has a method called ``get_node_topics_interface()`` which returns
- * either a pointer (const or not) to a NodeTopicsInterface or a
- * std::shared_ptr to a NodeTopicsInterface.
- */
-
-namespace rclcpp
-{
-namespace node_interfaces
-{
-
-namespace detail
-{
-
-// This is a meta-programming checker for if a given Node-like object has a
-// getter called get_node_topics_interface() which returns various types,
-// e.g. const pointer or a shared pointer.
-template<typename NodeType, typename ReturnType>
-struct has_get_node_topics_interface
-{
-private:
-  template<typename T>
-  static constexpr
-  auto
-  check(T *)->typename std::is_same<
-    decltype(std::declval<T>().get_node_topics_interface()),
-    ReturnType
-  >::type;
-
-  template<typename>
-  static constexpr
-  std::false_type
-  check(...);
-
-public:
-  using type = decltype(check<NodeType>(nullptr));
-  static constexpr bool value = type::value;
-};
-
-// If NodeType is a pointer to NodeTopicsInterface already (just normal function overload).
-inline
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface_from_pointer(rclcpp::node_interfaces::NodeTopicsInterface * pointer)
-{
-  return pointer;
-}
-
-// If NodeType has a method called get_node_topics_interface() which returns a shared pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_topics_interface<
-    typename std::remove_pointer<NodeType>::type,
-    std::shared_ptr<rclcpp::node_interfaces::NodeTopicsInterface>
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_topics_interface().get();
-}
-
-// If NodeType has a method called get_node_topics_interface() which returns a pointer.
-template<
-  typename NodeType,
-  typename std::enable_if<has_get_node_topics_interface<
-    typename std::remove_pointer<NodeType>::type,
-    rclcpp::node_interfaces::NodeTopicsInterface *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface_from_pointer(NodeType node_pointer)
-{
-  return node_pointer->get_node_topics_interface();
-}
-
-// Forward shared_ptr's to const node pointer signatures.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_same<
-    NodeType,
-    typename std::shared_ptr<typename std::remove_pointer<NodeType>::type::element_type> *
-  >::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface_from_pointer(NodeType node_shared_pointer)
-{
-  return get_node_topics_interface_from_pointer(node_shared_pointer->get());
-}
-
-}  // namespace detail
-
-/// Get the NodeTopicsInterface as a pointer from a pointer to a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<std::is_pointer<NodeType>::value, int>::type = 0
->
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface(NodeType node_pointer)
-{
-  // Forward pointers to detail implmentation directly.
-  return detail::get_node_topics_interface_from_pointer(node_pointer);
-}
-
-/// Get the NodeTopicsInterface as a pointer from a "Node like" object.
-template<
-  typename NodeType,
-  typename std::enable_if<
-    !std::is_pointer<typename std::remove_reference<NodeType>::type>::value, int
-  >::type = 0
->
-rclcpp::node_interfaces::NodeTopicsInterface *
-get_node_topics_interface(NodeType && node_reference)
-{
-  // Forward references to detail implmentation as a pointer.
-  return detail::get_node_topics_interface_from_pointer(&node_reference);
-}
-
-}  // namespace node_interfaces
-}  // namespace rclcpp
-
-#endif  // RCLCPP__NODE_INTERFACES__GET_NODE_TOPICS_INTERFACE_HPP_

rclcpp/include/rclcpp/node_interfaces/node_base.hpp

@@ -15,11 +15,14 @@
 #ifndef RCLCPP__NODE_INTERFACES__NODE_BASE_HPP_
 #define RCLCPP__NODE_INTERFACES__NODE_BASE_HPP_
 
+#include <functional>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <vector>
 
 #include "rcl/node.h"
+#include "rclcpp/callback_group.hpp"
 #include "rclcpp/context.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_base_interface.hpp"
@@ -31,7 +34,7 @@ namespace node_interfaces
 {
 
 /// Implementation of the NodeBase part of the Node API.
-class NodeBase : public NodeBaseInterface
+class NodeBase : public NodeBaseInterface, public std::enable_shared_from_this<NodeBase>
 {
 public:
   RCLCPP_SMART_PTR_ALIASES_ONLY(NodeBase)
@@ -50,93 +53,81 @@ public:
   ~NodeBase();
 
   RCLCPP_PUBLIC
-
   const char *
   get_name() const override;
 
   RCLCPP_PUBLIC
-
   const char *
   get_namespace() const override;
 
   RCLCPP_PUBLIC
-
   const char *
   get_fully_qualified_name() const override;
 
   RCLCPP_PUBLIC
-
   rclcpp::Context::SharedPtr
   get_context() override;
 
   RCLCPP_PUBLIC
-
   rcl_node_t *
   get_rcl_node_handle() override;
 
   RCLCPP_PUBLIC
-
   const rcl_node_t *
   get_rcl_node_handle() const override;
 
   RCLCPP_PUBLIC
-
   std::shared_ptr<rcl_node_t>
   get_shared_rcl_node_handle() override;
 
   RCLCPP_PUBLIC
-
   std::shared_ptr<const rcl_node_t>
   get_shared_rcl_node_handle() const override;
 
   RCLCPP_PUBLIC
-
-  bool
-  assert_liveliness() const override;
-
-  RCLCPP_PUBLIC
-
   rclcpp::CallbackGroup::SharedPtr
-  create_callback_group(rclcpp::CallbackGroupType group_type) override;
+  create_callback_group(
+    rclcpp::CallbackGroupType group_type,
+    bool automatically_add_to_executor_with_node = true) override;
 
   RCLCPP_PUBLIC
-
   rclcpp::CallbackGroup::SharedPtr
   get_default_callback_group() override;
 
   RCLCPP_PUBLIC
-
   bool
   callback_group_in_node(rclcpp::CallbackGroup::SharedPtr group) override;
 
+  /// Iterate over the stored callback groups, calling the given function on each valid one.
+  /**
+   * This method is called in a thread-safe way, and also makes sure to only call the given
+   * function on those items that are still valid.
+   *
+   * \param[in] func The callback function to call on each valid callback group.
+   */
   RCLCPP_PUBLIC
-
-  const std::vector<rclcpp::CallbackGroup::WeakPtr> &
-  get_callback_groups() const override;
+  void
+  for_each_callback_group(const CallbackGroupFunction & func) override;
 
   RCLCPP_PUBLIC
-
   std::atomic_bool &
   get_associated_with_executor_atomic() override;
 
   RCLCPP_PUBLIC
-
-  rcl_guard_condition_t *
+  rclcpp::GuardCondition &
   get_notify_guard_condition() override;
 
   RCLCPP_PUBLIC
-
-  std::unique_lock<std::recursive_mutex>
-  acquire_notify_guard_condition_lock() const override;
-
-  RCLCPP_PUBLIC
-
   bool
   get_use_intra_process_default() const override;
 
   bool
   get_enable_topic_statistics_default() const override;
 
+  std::string
+  resolve_topic_or_service_name(
+    const std::string & name, bool is_service, bool only_expand = false) const override;
+
 private:
   RCLCPP_DISABLE_COPY(NodeBase)
 
@@ -147,13 +138,14 @@ private:
   std::shared_ptr<rcl_node_t> node_handle_;
 
   rclcpp::CallbackGroup::SharedPtr default_callback_group_;
+  std::mutex callback_groups_mutex_;
   std::vector<rclcpp::CallbackGroup::WeakPtr> callback_groups_;
 
   std::atomic_bool associated_with_executor_;
 
   /// Guard condition for notifying the Executor of changes to this node.
   mutable std::recursive_mutex notify_guard_condition_mutex_;
-  rcl_guard_condition_t notify_guard_condition_ = rcl_get_zero_initialized_guard_condition();
+  rclcpp::GuardCondition notify_guard_condition_;
   bool notify_guard_condition_is_valid_;
 };
 

rclcpp/include/rclcpp/node_interfaces/node_base_interface.hpp

@@ -24,6 +24,7 @@
 
 #include "rclcpp/callback_group.hpp"
 #include "rclcpp/context.hpp"
+#include "rclcpp/guard_condition.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/visibility_control.hpp"
 
@@ -102,17 +103,13 @@ public:
   std::shared_ptr<const rcl_node_t>
   get_shared_rcl_node_handle() const = 0;
 
-  /// Manually assert that this Node is alive (for RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_NODE).
-  RCLCPP_PUBLIC
-  virtual
-  bool
-  assert_liveliness() const = 0;
-
   /// Create and return a callback group.
   RCLCPP_PUBLIC
   virtual
   rclcpp::CallbackGroup::SharedPtr
-  create_callback_group(rclcpp::CallbackGroupType group_type) = 0;
+  create_callback_group(
+    rclcpp::CallbackGroupType group_type,
+    bool automatically_add_to_executor_with_node = true) = 0;
 
   /// Return the default callback group.
   RCLCPP_PUBLIC
@@ -126,11 +123,19 @@ public:
   bool
   callback_group_in_node(rclcpp::CallbackGroup::SharedPtr group) = 0;
 
-  /// Return list of callback groups associated with this node.
+  using CallbackGroupFunction = std::function<void (rclcpp::CallbackGroup::SharedPtr)>;
+
+  /// Iterate over the stored callback groups, calling the given function on each valid one.
+  /**
+   * This method is called in a thread-safe way, and also makes sure to only call the given
+   * function on those items that are still valid.
+   *
+   * \param[in] func The callback function to call on each valid callback group.
+   */
   RCLCPP_PUBLIC
   virtual
-  const std::vector<rclcpp::CallbackGroup::WeakPtr> &
-  get_callback_groups() const = 0;
+  void
+  for_each_callback_group(const CallbackGroupFunction & func) = 0;
 
   /// Return the atomic bool which is used to ensure only one executor is used.
   RCLCPP_PUBLIC
@@ -138,24 +143,17 @@ public:
   std::atomic_bool &
   get_associated_with_executor_atomic() = 0;
 
-  /// Return guard condition that should be notified when the internal node state changes.
+  /// Return a guard condition that should be notified when the internal node state changes.
   /**
    * For example, this should be notified when a publisher is added or removed.
    *
-   * \return the rcl_guard_condition_t if it is valid, else nullptr
+   * \return the GuardCondition if it is valid, else thow runtime error
    */
   RCLCPP_PUBLIC
   virtual
-  rcl_guard_condition_t *
+  rclcpp::GuardCondition &
   get_notify_guard_condition() = 0;
 
-  /// Acquire and return a scoped lock that protects the notify guard condition.
-  /** This should be used when triggering the notify guard condition. */
-  RCLCPP_PUBLIC
-  virtual
-  std::unique_lock<std::recursive_mutex>
-  acquire_notify_guard_condition_lock() const = 0;
-
   /// Return the default preference for using intra process communication.
   RCLCPP_PUBLIC
   virtual
@@ -167,6 +165,13 @@ public:
   virtual
   bool
   get_enable_topic_statistics_default() const = 0;
+
+  /// Expand and remap a given topic or service name.
+  RCLCPP_PUBLIC
+  virtual
+  std::string
+  resolve_topic_or_service_name(
+    const std::string & name, bool is_service, bool only_expand = false) const = 0;
 };
 
 }  // namespace node_interfaces

rclcpp/include/rclcpp/node_interfaces/node_graph.hpp

@@ -20,6 +20,7 @@
 #include <memory>
 #include <mutex>
 #include <string>
+#include <tuple>
 #include <utility>
 #include <vector>
 
@@ -57,66 +58,84 @@ public:
   ~NodeGraph();
 
   RCLCPP_PUBLIC
-
   std::map<std::string, std::vector<std::string>>
   get_topic_names_and_types(bool no_demangle = false) const override;
 
   RCLCPP_PUBLIC
-
   std::map<std::string, std::vector<std::string>>
   get_service_names_and_types() const override;
 
   RCLCPP_PUBLIC
+  std::map<std::string, std::vector<std::string>>
+  get_service_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_) const override;
 
+  RCLCPP_PUBLIC
+  std::map<std::string, std::vector<std::string>>
+  get_client_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_) const override;
+
+  RCLCPP_PUBLIC
+  std::map<std::string, std::vector<std::string>>
+  get_publisher_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_,
+    bool no_demangle = false) const override;
+
+  RCLCPP_PUBLIC
+  std::map<std::string, std::vector<std::string>>
+  get_subscriber_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_,
+    bool no_demangle = false) const override;
+
+  RCLCPP_PUBLIC
   std::vector<std::string>
   get_node_names() const override;
 
   RCLCPP_PUBLIC
+  std::vector<std::tuple<std::string, std::string, std::string>>
+  get_node_names_with_enclaves() const override;
 
+  RCLCPP_PUBLIC
   std::vector<std::pair<std::string, std::string>>
   get_node_names_and_namespaces() const override;
 
   RCLCPP_PUBLIC
-
   size_t
   count_publishers(const std::string & topic_name) const override;
 
   RCLCPP_PUBLIC
-
   size_t
   count_subscribers(const std::string & topic_name) const override;
 
   RCLCPP_PUBLIC
-
   const rcl_guard_condition_t *
   get_graph_guard_condition() const override;
 
   RCLCPP_PUBLIC
-
   void
   notify_graph_change() override;
 
   RCLCPP_PUBLIC
-
   void
   notify_shutdown() override;
 
   RCLCPP_PUBLIC
-
   rclcpp::Event::SharedPtr
   get_graph_event() override;
 
   RCLCPP_PUBLIC
-
   void
   wait_for_graph_change(
     rclcpp::Event::SharedPtr event,
     std::chrono::nanoseconds timeout) override;
 
   RCLCPP_PUBLIC
-
   size_t
-  count_graph_users() override;
+  count_graph_users() const override;
 
   RCLCPP_PUBLIC
   std::vector<rclcpp::TopicEndpointInfo>

rclcpp/include/rclcpp/node_interfaces/node_graph_interface.hpp

@@ -20,6 +20,7 @@
 #include <chrono>
 #include <map>
 #include <string>
+#include <tuple>
 #include <utility>
 #include <vector>
 
@@ -146,6 +147,9 @@ public:
   /**
    * A topic is considered to exist when at least one publisher or subscriber
    * exists for it, whether they be local or remote to this process.
+   * The returned names are the actual names of the topics, either announced by another nodes or by this one.
+   * Attempting to create publishers or subscribers using names returned by this function may not
+   * result in the desired topic name being used depending on the remap rules in use.
    *
    * \param[in] no_demangle if true, topic names and types are not demangled
    */
@@ -159,31 +163,130 @@ public:
    * A service is considered to exist when at least one service server or
    * service client exists for it, whether they be local or remote to this
    * process.
+   * The returned names are the actual names of the services, either announced by another nodes or by this one.
+   * Attempting to create clients or services using names returned by this function may not result in
+   * the desired service name being used depending on the remap rules in use.
    */
   RCLCPP_PUBLIC
   virtual
   std::map<std::string, std::vector<std::string>>
   get_service_names_and_types() const = 0;
 
+  /// Return a map of existing service names to list of service types for a specific node.
+  /**
+   * This function only considers services - not clients.
+   * The returned names are the actual names after remap rules applied.
+   * Attempting to create service clients using names returned by this function may not
+   * result in the desired service name being used depending on the remap rules in use.
+   *
+   * \param[in] node_name name of the node
+   * \param[in] namespace_ namespace of the node
+   */
+  RCLCPP_PUBLIC
+  virtual
+  std::map<std::string, std::vector<std::string>>
+  get_service_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_) const = 0;
+
+  /// Return a map of existing service names and types with a specific node.
+  /**
+   * This function only considers clients - not service servers.
+   * The returned names are the actual names after remap rules applied.
+   * Attempting to create service servers using names returned by this function may not
+   * result in the desired service name being used depending on the remap rules in use.
+   *
+   * \param[in] node_name name of the node
+   * \param[in] namespace_ namespace of the node
+   */
+  RCLCPP_PUBLIC
+  virtual
+  std::map<std::string, std::vector<std::string>>
+  get_client_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_) const = 0;
+
+  /// Return a map of existing topic names to list of topic types for a specific node.
+  /**
+   * This function only considers publishers - not subscribers.
+   * The returned names are the actual names after remap rules applied.
+   * Attempting to create publishers or subscribers using names returned by this function may not
+   * result in the desired topic name being used depending on the remap rules in use.
+   *
+   * \param[in] node_name name of the node
+   * \param[in] namespace_ namespace of the node
+   * \param[in] no_demangle if true, topic names and types are not demangled
+   */
+  RCLCPP_PUBLIC
+  virtual
+  std::map<std::string, std::vector<std::string>>
+  get_publisher_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_,
+    bool no_demangle = false) const = 0;
+
+  /// Return a map of existing topic names to list of topic types for a specific node.
+  /**
+   * This function only considers subscribers - not publishers.
+   * The returned names are the actual names after remap rules applied.
+   * Attempting to create publishers or subscribers using names returned by this function may not
+   * result in the desired topic name being used depending on the remap rules in use.
+   *
+   * \param[in] node_name name of the node
+   * \param[in] namespace_ namespace of the node
+   * \param[in] no_demangle if true, topic names and types are not demangled
+   */
+  RCLCPP_PUBLIC
+  virtual
+  std::map<std::string, std::vector<std::string>>
+  get_subscriber_names_and_types_by_node(
+    const std::string & node_name,
+    const std::string & namespace_,
+    bool no_demangle = false) const = 0;
+
   /// Return a vector of existing node names (string).
+  /*
+   * The returned names are the actual names after remap rules applied.
+   */
   RCLCPP_PUBLIC
   virtual
   std::vector<std::string>
   get_node_names() const = 0;
 
+  /// Return a vector of existing node names, namespaces and enclaves (tuple of string).
+  /*
+   * The returned names are the actual names after remap rules applied.
+   * The enclaves contain the runtime security artifacts, those can be
+   * used to establish secured network.
+   * See https://design.ros2.org/articles/ros2_security_enclaves.html
+   */
+  RCLCPP_PUBLIC
+  virtual
+  std::vector<std::tuple<std::string, std::string, std::string>>
+  get_node_names_with_enclaves() const = 0;
+
   /// Return a vector of existing node names and namespaces (pair of string).
+  /*
+   * The returned names are the actual names after remap rules applied.
+   */
   RCLCPP_PUBLIC
   virtual
   std::vector<std::pair<std::string, std::string>>
   get_node_names_and_namespaces() const = 0;
 
   /// Return the number of publishers that are advertised on a given topic.
+  /*
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   */
   RCLCPP_PUBLIC
   virtual
   size_t
   count_publishers(const std::string & topic_name) const = 0;
 
   /// Return the number of subscribers who have created a subscription for a given topic.
+  /*
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   */
   RCLCPP_PUBLIC
   virtual
   size_t
@@ -249,10 +352,13 @@ public:
   RCLCPP_PUBLIC
   virtual
   size_t
-  count_graph_users() = 0;
+  count_graph_users() const = 0;
 
   /// Return the topic endpoint information about publishers on a given topic.
   /**
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
+   *   otherwise it should be a valid ROS topic name.
    * \sa rclcpp::Node::get_publishers_info_by_topic
    */
   RCLCPP_PUBLIC
@@ -262,6 +368,9 @@ public:
 
   /// Return the topic endpoint information about subscriptions on a given topic.
   /**
+   * \param[in] topic_name the actual topic name used; it will not be automatically remapped.
+   * \param[in] no_mangle if `true`, `topic_name` needs to be a valid middleware topic name,
+   *   otherwise it should be a valid ROS topic name.
    * \sa rclcpp::Node::get_subscriptions_info_by_topic
    */
   RCLCPP_PUBLIC

rclcpp/include/rclcpp/node_interfaces/node_logging.hpp

@@ -42,12 +42,10 @@ public:
   ~NodeLogging();
 
   RCLCPP_PUBLIC
-
   rclcpp::Logger
   get_logger() const override;
 
   RCLCPP_PUBLIC
-
   const char *
   get_logger_name() const override;
 

rclcpp/include/rclcpp/node_interfaces/node_parameters.hpp

@@ -21,6 +21,8 @@
 #include <string>
 #include <vector>
 
+#include "rcutils/macros.h"
+
 #include "rcl_interfaces/msg/list_parameters_result.hpp"
 #include "rcl_interfaces/msg/parameter_descriptor.hpp"
 #include "rcl_interfaces/msg/parameter_event.hpp"
@@ -106,8 +108,18 @@ public:
   declare_parameter(
     const std::string & name,
     const rclcpp::ParameterValue & default_value,
-    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
-    bool ignore_override) override;
+    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor{},
+    bool ignore_override = false) override;
+
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
+    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor(),
+    bool ignore_override = false) override;
 
   RCLCPP_PUBLIC
   void
@@ -160,6 +172,7 @@ public:
   list_parameters(const std::vector<std::string> & prefixes, uint64_t depth) const override;
 
   RCLCPP_PUBLIC
+  RCUTILS_WARN_UNUSED
   OnSetParametersCallbackHandle::SharedPtr
   add_on_set_parameters_callback(OnParametersSetCallbackType callback) override;
 
@@ -167,10 +180,6 @@ public:
   void
   remove_on_set_parameters_callback(const OnSetParametersCallbackHandle * const handler) override;
 
-  RCLCPP_PUBLIC
-  OnParametersSetCallbackType
-  set_on_parameters_set_callback(OnParametersSetCallbackType callback) override;
-
   RCLCPP_PUBLIC
   const std::map<std::string, rclcpp::ParameterValue> &
   get_parameter_overrides() const override;

rclcpp/include/rclcpp/node_interfaces/node_parameters_interface.hpp

@@ -64,7 +64,21 @@ public:
   const rclcpp::ParameterValue &
   declare_parameter(
     const std::string & name,
-    const rclcpp::ParameterValue & default_value = rclcpp::ParameterValue(),
+    const rclcpp::ParameterValue & default_value,
+    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor(),
+    bool ignore_override = false) = 0;
+
+  /// Declare a parameter.
+  /**
+   * \sa rclcpp::Node::declare_parameter
+   */
+  RCLCPP_PUBLIC
+  virtual
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
     const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
     rcl_interfaces::msg::ParameterDescriptor(),
     bool ignore_override = false) = 0;
@@ -96,7 +110,7 @@ public:
   std::vector<rcl_interfaces::msg::SetParametersResult>
   set_parameters(const std::vector<rclcpp::Parameter> & parameters) = 0;
 
-  /// Set and initialize a parameter, all at once.
+  /// Set one or more parameters, all at once.
   /**
    * \sa rclcpp::Node::set_parameters_atomically
    */
@@ -191,15 +205,6 @@ public:
   void
   remove_on_set_parameters_callback(const OnSetParametersCallbackHandle * const handler) = 0;
 
-  /// Register a callback for when parameters are being set, return an existing one.
-  /**
-   * \sa rclcpp::Node::set_on_parameters_set_callback
-   */
-  RCLCPP_PUBLIC
-  virtual
-  OnParametersSetCallbackType
-  set_on_parameters_set_callback(OnParametersSetCallbackType callback) = 0;
-
   /// Return the initial parameter values used by the NodeParameters to override default values.
   RCLCPP_PUBLIC
   virtual

rclcpp/include/rclcpp/node_interfaces/node_services.hpp

@@ -15,6 +15,8 @@
 #ifndef RCLCPP__NODE_INTERFACES__NODE_SERVICES_HPP_
 #define RCLCPP__NODE_INTERFACES__NODE_SERVICES_HPP_
 
+#include <string>
+
 #include "rclcpp/callback_group.hpp"
 #include "rclcpp/client.hpp"
 #include "rclcpp/macros.hpp"
@@ -42,19 +44,21 @@ public:
   ~NodeServices();
 
   RCLCPP_PUBLIC
-
   void
   add_client(
     rclcpp::ClientBase::SharedPtr client_base_ptr,
     rclcpp::CallbackGroup::SharedPtr group) override;
 
   RCLCPP_PUBLIC
-
   void
   add_service(
     rclcpp::ServiceBase::SharedPtr service_base_ptr,
     rclcpp::CallbackGroup::SharedPtr group) override;
 
+  RCLCPP_PUBLIC
+  std::string
+  resolve_service_name(const std::string & name, bool only_expand = false) const override;
+
 private:
   RCLCPP_DISABLE_COPY(NodeServices)
 

rclcpp/include/rclcpp/node_interfaces/node_services_interface.hpp

@@ -15,6 +15,8 @@
 #ifndef RCLCPP__NODE_INTERFACES__NODE_SERVICES_INTERFACE_HPP_
 #define RCLCPP__NODE_INTERFACES__NODE_SERVICES_INTERFACE_HPP_
 
+#include <string>
+
 #include "rclcpp/callback_group.hpp"
 #include "rclcpp/client.hpp"
 #include "rclcpp/macros.hpp"
@@ -49,6 +51,12 @@ public:
   add_service(
     rclcpp::ServiceBase::SharedPtr service_base_ptr,
     rclcpp::CallbackGroup::SharedPtr group) = 0;
+
+  /// Get the remapped and expanded service name given a input name.
+  RCLCPP_PUBLIC
+  virtual
+  std::string
+  resolve_service_name(const std::string & name, bool only_expand = false) const = 0;
 };
 
 }  // namespace node_interfaces

rclcpp/include/rclcpp/node_interfaces/node_time_source.hpp

@@ -24,6 +24,7 @@
 #include "rclcpp/node_interfaces/node_services_interface.hpp"
 #include "rclcpp/node_interfaces/node_time_source_interface.hpp"
 #include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/qos.hpp"
 #include "rclcpp/time_source.hpp"
 #include "rclcpp/visibility_control.hpp"
 
@@ -46,7 +47,9 @@ public:
     rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services,
     rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging,
     rclcpp::node_interfaces::NodeClockInterface::SharedPtr node_clock,
-    rclcpp::node_interfaces::NodeParametersInterface::SharedPtr node_parameters
+    rclcpp::node_interfaces::NodeParametersInterface::SharedPtr node_parameters,
+    const rclcpp::QoS & qos = rclcpp::ClockQoS(),
+    bool use_clock_thread = true
   );
 
   RCLCPP_PUBLIC

rclcpp/include/rclcpp/node_interfaces/node_timers.hpp

@@ -42,7 +42,6 @@ public:
 
   /// Add a timer to the node.
   RCLCPP_PUBLIC
-
   void
   add_timer(
     rclcpp::TimerBase::SharedPtr timer,

rclcpp/include/rclcpp/node_interfaces/node_topics.hpp

@@ -20,11 +20,16 @@
 #include "rcl/publisher.h"
 #include "rcl/subscription.h"
 
+#include "rclcpp/callback_group.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/node_interfaces/node_timers_interface.hpp"
 #include "rclcpp/node_interfaces/node_topics_interface.hpp"
-#include "rclcpp/publisher.hpp"
+#include "rclcpp/publisher_base.hpp"
 #include "rclcpp/publisher_factory.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/subscription_base.hpp"
+#include "rclcpp/subscription_factory.hpp"
 #include "rclcpp/visibility_control.hpp"
 
 namespace rclcpp
@@ -39,7 +44,9 @@ public:
   RCLCPP_SMART_PTR_ALIASES_ONLY(NodeTopicsInterface)
 
   RCLCPP_PUBLIC
-  explicit NodeTopics(rclcpp::node_interfaces::NodeBaseInterface * node_base);
+  NodeTopics(
+    rclcpp::node_interfaces::NodeBaseInterface * node_base,
+    rclcpp::node_interfaces::NodeTimersInterface * node_timers);
 
   RCLCPP_PUBLIC
   ~NodeTopics() override;
@@ -74,10 +81,19 @@ public:
   rclcpp::node_interfaces::NodeBaseInterface *
   get_node_base_interface() const override;
 
+  RCLCPP_PUBLIC
+  rclcpp::node_interfaces::NodeTimersInterface *
+  get_node_timers_interface() const override;
+
+  RCLCPP_PUBLIC
+  std::string
+  resolve_topic_name(const std::string & name, bool only_expand = false) const override;
+
 private:
   RCLCPP_DISABLE_COPY(NodeTopics)
 
   rclcpp::node_interfaces::NodeBaseInterface * node_base_;
+  rclcpp::node_interfaces::NodeTimersInterface * node_timers_;
 };
 
 }  // namespace node_interfaces

rclcpp/include/rclcpp/node_interfaces/node_topics_interface.hpp

@@ -25,6 +25,7 @@
 #include "rclcpp/callback_group.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/node_interfaces/node_timers_interface.hpp"
 #include "rclcpp/publisher.hpp"
 #include "rclcpp/publisher_factory.hpp"
 #include "rclcpp/subscription.hpp"
@@ -80,6 +81,17 @@ public:
   virtual
   rclcpp::node_interfaces::NodeBaseInterface *
   get_node_base_interface() const = 0;
+
+  RCLCPP_PUBLIC
+  virtual
+  rclcpp::node_interfaces::NodeTimersInterface *
+  get_node_timers_interface() const = 0;
+
+  /// Get a remapped and expanded topic name given an input name.
+  RCLCPP_PUBLIC
+  virtual
+  std::string
+  resolve_topic_name(const std::string & name, bool only_expand = false) const = 0;
 };
 
 }  // namespace node_interfaces

rclcpp/include/rclcpp/node_interfaces/node_waitables.hpp

@@ -41,14 +41,12 @@ public:
   ~NodeWaitables();
 
   RCLCPP_PUBLIC
-
   void
   add_waitable(
     rclcpp::Waitable::SharedPtr waitable_base_ptr,
     rclcpp::CallbackGroup::SharedPtr group) override;
 
   RCLCPP_PUBLIC
-
   void
   remove_waitable(
     rclcpp::Waitable::SharedPtr waitable_ptr,

rclcpp/include/rclcpp/node_options.hpp

@@ -42,10 +42,14 @@ public:
    *   - arguments = {}
    *   - parameter_overrides = {}
    *   - use_global_arguments = true
+   *   - enable_rosout = true
    *   - use_intra_process_comms = false
    *   - enable_topic_statistics = false
    *   - start_parameter_services = true
    *   - start_parameter_event_publisher = true
+   *   - clock_qos = rclcpp::ClockQoS()
+   *   - use_clock_thread = true
+   *   - rosout_qos = rclcpp::RosoutQoS()
    *   - parameter_event_qos = rclcpp::ParameterEventQoS
    *     - with history setting and depth from rmw_qos_profile_parameter_events
    *   - parameter_event_publisher_options = rclcpp::PublisherOptionsBase
@@ -77,6 +81,9 @@ public:
    * This data structure is created lazily, on the first call to this function.
    * Repeated calls will not regenerate it unless one of the input settings
    * changed, like arguments, use_global_arguments, or the rcl allocator.
+   *
+   * \return a const rcl_node_options_t structure used by the node
+   * \throws exceptions::UnknownROSArgsError if there are unknown ROS arguments
    */
   RCLCPP_PUBLIC
   const rcl_node_options_t *
@@ -240,6 +247,33 @@ public:
   NodeOptions &
   start_parameter_event_publisher(bool start_parameter_event_publisher);
 
+  /// Return a reference to the clock QoS.
+  RCLCPP_PUBLIC
+  const rclcpp::QoS &
+  clock_qos() const;
+
+  /// Set the clock QoS.
+  /**
+   * The QoS settings to be used for the publisher on /clock topic, if enabled.
+   */
+  RCLCPP_PUBLIC
+  NodeOptions &
+  clock_qos(const rclcpp::QoS & clock_qos);
+
+
+  /// Return the use_clock_thread flag.
+  RCLCPP_PUBLIC
+  bool
+  use_clock_thread() const;
+
+  /// Set the use_clock_thread flag, return this for parameter idiom.
+  /**
+   * If true, a dedicated thread will be used to subscribe to "/clock" topic.
+   */
+  RCLCPP_PUBLIC
+  NodeOptions &
+  use_clock_thread(bool use_clock_thread);
+
   /// Return a reference to the parameter_event_qos QoS.
   RCLCPP_PUBLIC
   const rclcpp::QoS &
@@ -253,6 +287,19 @@ public:
   NodeOptions &
   parameter_event_qos(const rclcpp::QoS & parameter_event_qos);
 
+  /// Return a reference to the rosout QoS.
+  RCLCPP_PUBLIC
+  const rclcpp::QoS &
+  rosout_qos() const;
+
+  /// Set the rosout QoS.
+  /**
+   * The QoS settings to be used for the publisher on /rosout topic, if enabled.
+   */
+  RCLCPP_PUBLIC
+  NodeOptions &
+  rosout_qos(const rclcpp::QoS & rosout_qos);
+
   /// Return a reference to the parameter_event_publisher_options.
   RCLCPP_PUBLIC
   const rclcpp::PublisherOptionsBase &
@@ -303,6 +350,9 @@ public:
    * global arguments (e.g. parameter overrides from a YAML file), which are
    * not explicitly declared will not appear on the node at all, even if
    * `allow_undeclared_parameters` is true.
+   * Parameter declaration from overrides is done in the node's base constructor,
+   * so the user must take care to check if the parameter is already (e.g.
+   * automatically) declared before declaring it themselves.
    * Already declared parameters will not be re-declared, and parameters
    * declared in this way will use the default constructed ParameterDescriptor.
    */
@@ -324,11 +374,6 @@ public:
   NodeOptions &
   allocator(rcl_allocator_t allocator);
 
-protected:
-  /// Retrieve the ROS_DOMAIN_ID environment variable and populate options.
-  size_t
-  get_domain_id_from_env() const;
-
 private:
   // This is mutable to allow for a const accessor which lazily creates the node options instance.
   /// Underlying rcl_node_options structure.
@@ -356,10 +401,16 @@ private:
 
   bool start_parameter_event_publisher_ {true};
 
+  rclcpp::QoS clock_qos_ = rclcpp::ClockQoS();
+
+  bool use_clock_thread_ {true};
+
   rclcpp::QoS parameter_event_qos_ = rclcpp::ParameterEventsQoS(
     rclcpp::QoSInitialization::from_rmw(rmw_qos_profile_parameter_events)
   );
 
+  rclcpp::QoS rosout_qos_ = rclcpp::RosoutQoS();
+
   rclcpp::PublisherOptionsBase parameter_event_publisher_options_ = rclcpp::PublisherOptionsBase();
 
   bool allow_undeclared_parameters_ {false};

rclcpp/include/rclcpp/parameter.hpp

@@ -83,18 +83,22 @@ public:
   bool
   operator!=(const Parameter & rhs) const;
 
+  /// Get the type of the parameter
   RCLCPP_PUBLIC
   ParameterType
   get_type() const;
 
+  /// Get the type name of the parameter
   RCLCPP_PUBLIC
   std::string
   get_type_name() const;
 
+  /// Get the name of the parameter
   RCLCPP_PUBLIC
   const std::string &
   get_name() const;
 
+  /// Get value of parameter as a parameter message.
   RCLCPP_PUBLIC
   rcl_interfaces::msg::ParameterValue
   get_value_message() const;
@@ -105,6 +109,9 @@ public:
   get_parameter_value() const;
 
   /// Get value of parameter using rclcpp::ParameterType as template argument.
+  /**
+   * \throws rclcpp::exceptions::InvalidParameterTypeException if the type doesn't match
+   */
   template<ParameterType ParamT>
   decltype(auto)
   get_value() const
@@ -117,50 +124,89 @@ public:
   decltype(auto)
   get_value() const;
 
+  /// Get value of parameter as boolean.
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   bool
   as_bool() const;
 
+  /// Get value of parameter as integer.
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   int64_t
   as_int() const;
 
+  /// Get value of parameter as double.
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   double
   as_double() const;
 
+  /// Get value of parameter as string.
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::string &
   as_string() const;
 
+  /// Get value of parameter as byte array (vector<uint8_t>).
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::vector<uint8_t> &
   as_byte_array() const;
 
+  /// Get value of parameter as bool array (vector<bool>).
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::vector<bool> &
   as_bool_array() const;
 
+  /// Get value of parameter as integer array (vector<int64_t>).
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::vector<int64_t> &
   as_integer_array() const;
 
+  /// Get value of parameter as double array (vector<double>).
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::vector<double> &
   as_double_array() const;
 
+  /// Get value of parameter as string array (vector<std::string>).
+  /**
+   * \throws rclcpp::ParameterTypeException if the type doesn't match
+   */
   RCLCPP_PUBLIC
   const std::vector<std::string> &
   as_string_array() const;
 
+  /// Convert a parameter message in a Parameter class object.
   RCLCPP_PUBLIC
   static Parameter
   from_parameter_msg(const rcl_interfaces::msg::Parameter & parameter);
 
+  /// Convert the class in a parameter message.
   RCLCPP_PUBLIC
   rcl_interfaces::msg::Parameter
   to_parameter_msg() const;
 
+  /// Get value of parameter as a string.
   RCLCPP_PUBLIC
   std::string
   value_to_string() const;
@@ -218,6 +264,7 @@ get_value_helper<rclcpp::Parameter>(const rclcpp::Parameter * parameter)
 
 }  // namespace detail
 
+/// \cond
 template<typename T>
 decltype(auto)
 Parameter::get_value() const
@@ -229,6 +276,7 @@ Parameter::get_value() const
     throw exceptions::InvalidParameterTypeException(this->name_, ex.what());
   }
 }
+/// \endcond
 
 }  // namespace rclcpp
 

rclcpp/include/rclcpp/parameter_client.hpp

@@ -15,6 +15,8 @@
 #ifndef RCLCPP__PARAMETER_CLIENT_HPP_
 #define RCLCPP__PARAMETER_CLIENT_HPP_
 
+#include <functional>
+#include <future>
 #include <memory>
 #include <string>
 #include <utility>
@@ -29,11 +31,14 @@
 #include "rcl_interfaces/srv/list_parameters.hpp"
 #include "rcl_interfaces/srv/set_parameters.hpp"
 #include "rcl_interfaces/srv/set_parameters_atomically.hpp"
+#include "rcl_yaml_param_parser/parser.h"
+#include "rclcpp/exceptions.hpp"
 #include "rclcpp/executors.hpp"
 #include "rclcpp/create_subscription.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node.hpp"
 #include "rclcpp/parameter.hpp"
+#include "rclcpp/parameter_map.hpp"
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/visibility_control.hpp"
 #include "rmw/rmw.h"
@@ -46,6 +51,16 @@ class AsyncParametersClient
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(AsyncParametersClient)
 
+  /// Create an async parameters client.
+  /**
+   * \param[in] node_base_interface The node base interface of the corresponding node.
+   * \param[in] node_topics_interface Node topic base interface.
+   * \param[in] node_graph_interface The node graph interface of the corresponding node.
+   * \param[in] node_services_interface Node service interface.
+   * \param[in] remote_node_name (optional) name of the remote node
+   * \param[in] qos_profile (optional) The rmw qos profile to use to subscribe
+   * \param[in] group (optional) The async parameter client will be added to this callback group.
+   */
   RCLCPP_PUBLIC
   AsyncParametersClient(
     const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
@@ -56,19 +71,51 @@ public:
     const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters,
     rclcpp::CallbackGroup::SharedPtr group = nullptr);
 
-  RCLCPP_PUBLIC
-  AsyncParametersClient(
-    const rclcpp::Node::SharedPtr node,
+  /// Constructor
+  /**
+   * \param[in] node The async paramters client will be added to this node.
+   * \param[in] remote_node_name (optional) name of the remote node
+   * \param[in] qos_profile (optional) The rmw qos profile to use to subscribe
+   * \param[in] group (optional) The async parameter client will be added to this callback group.
+   */
+  template<typename NodeT>
+  explicit AsyncParametersClient(
+    const std::shared_ptr<NodeT> node,
     const std::string & remote_node_name = "",
     const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters,
-    rclcpp::CallbackGroup::SharedPtr group = nullptr);
+    rclcpp::CallbackGroup::SharedPtr group = nullptr)
+  : AsyncParametersClient(
+      node->get_node_base_interface(),
+      node->get_node_topics_interface(),
+      node->get_node_graph_interface(),
+      node->get_node_services_interface(),
+      remote_node_name,
+      qos_profile,
+      group)
+  {}
 
-  RCLCPP_PUBLIC
-  AsyncParametersClient(
-    rclcpp::Node * node,
+  /// Constructor
+  /**
+   * \param[in] node The  async paramters client will be added to this node.
+   * \param[in] remote_node_name (optional) name of the remote node
+   * \param[in] qos_profile (optional) The rmw qos profile to use to subscribe
+   * \param[in] group (optional) The async parameter client will be added to this callback group.
+   */
+  template<typename NodeT>
+  explicit AsyncParametersClient(
+    NodeT * node,
     const std::string & remote_node_name = "",
     const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters,
-    rclcpp::CallbackGroup::SharedPtr group = nullptr);
+    rclcpp::CallbackGroup::SharedPtr group = nullptr)
+  : AsyncParametersClient(
+      node->get_node_base_interface(),
+      node->get_node_topics_interface(),
+      node->get_node_graph_interface(),
+      node->get_node_services_interface(),
+      remote_node_name,
+      qos_profile,
+      group)
+  {}
 
   RCLCPP_PUBLIC
   std::shared_future<std::vector<rclcpp::Parameter>>
@@ -78,6 +125,14 @@ public:
       void(std::shared_future<std::vector<rclcpp::Parameter>>)
     > callback = nullptr);
 
+  RCLCPP_PUBLIC
+  std::shared_future<std::vector<rcl_interfaces::msg::ParameterDescriptor>>
+  describe_parameters(
+    const std::vector<std::string> & names,
+    std::function<
+      void(std::shared_future<std::vector<rcl_interfaces::msg::ParameterDescriptor>>)
+    > callback = nullptr);
+
   RCLCPP_PUBLIC
   std::shared_future<std::vector<rclcpp::ParameterType>>
   get_parameter_types(
@@ -102,6 +157,42 @@ public:
       void(std::shared_future<rcl_interfaces::msg::SetParametersResult>)
     > callback = nullptr);
 
+  /// Delete several parameters at once.
+  /**
+   * This function behaves like command-line tool `ros2 param delete` would.
+   *
+   * \param parameters_names vector of parameters names
+   * \return the future of the set_parameter service used to delete the parameters
+   */
+  RCLCPP_PUBLIC
+  std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+  delete_parameters(
+    const std::vector<std::string> & parameters_names);
+
+  /// Load parameters from yaml file.
+  /**
+   * This function behaves like command-line tool `ros2 param load` would.
+   *
+   * \param yaml_filename the full name of the yaml file
+   * \return the future of the set_parameter service used to load the parameters
+   */
+  RCLCPP_PUBLIC
+  std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+  load_parameters(
+    const std::string & yaml_filename);
+
+  /// Load parameters from parameter map.
+  /**
+   * This function filters the parameters to be set based on the node name.
+   *
+   * \param parameter_map named parameters to be loaded
+   * \return the future of the set_parameter service used to load the parameters
+   * \throw InvalidParametersException if there is no parameter to set
+   */
+  RCLCPP_PUBLIC
+  std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+  load_parameters(const rclcpp::ParameterMap & parameter_map);
+
   RCLCPP_PUBLIC
   std::shared_future<rcl_interfaces::msg::ListParametersResult>
   list_parameters(
@@ -153,16 +244,32 @@ public:
   {
     return rclcpp::create_subscription<rcl_interfaces::msg::ParameterEvent>(
       node,
-      "parameter_events",
+      "/parameter_events",
       qos,
       std::forward<CallbackT>(callback),
       options);
   }
 
+  /// Return if the parameter services are ready.
+  /**
+   * This method checks the following services:
+   *  - get parameter
+   *  - get parameter
+   *  - set parameters
+   *  - list parameters
+   *  - describe parameters
+   *
+   * \return `true` if the service is ready, `false` otherwise
+   */
   RCLCPP_PUBLIC
   bool
   service_is_ready() const;
 
+  /// Wait for the services to be ready.
+  /**
+   * \param timeout maximum time to wait
+   * \return `true` if the services are ready and the timeout is not over, `false` otherwise
+   */
   template<typename RepT = int64_t, typename RatioT = std::milli>
   bool
   wait_for_service(
@@ -197,31 +304,61 @@ class SyncParametersClient
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(SyncParametersClient)
 
-  RCLCPP_PUBLIC
+  template<typename NodeT>
   explicit SyncParametersClient(
-    rclcpp::Node::SharedPtr node,
+    std::shared_ptr<NodeT> node,
     const std::string & remote_node_name = "",
-    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters);
+    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters)
+  : SyncParametersClient(
+      std::make_shared<rclcpp::executors::SingleThreadedExecutor>(),
+      node,
+      remote_node_name,
+      qos_profile)
+  {}
 
-  RCLCPP_PUBLIC
+  template<typename NodeT>
   SyncParametersClient(
     rclcpp::Executor::SharedPtr executor,
-    rclcpp::Node::SharedPtr node,
+    std::shared_ptr<NodeT> node,
     const std::string & remote_node_name = "",
-    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters);
+    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters)
+  : SyncParametersClient(
+      executor,
+      node->get_node_base_interface(),
+      node->get_node_topics_interface(),
+      node->get_node_graph_interface(),
+      node->get_node_services_interface(),
+      remote_node_name,
+      qos_profile)
+  {}
 
-  RCLCPP_PUBLIC
+  template<typename NodeT>
   explicit SyncParametersClient(
-    rclcpp::Node * node,
+    NodeT * node,
     const std::string & remote_node_name = "",
-    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters);
+    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters)
+  : SyncParametersClient(
+      std::make_shared<rclcpp::executors::SingleThreadedExecutor>(),
+      node,
+      remote_node_name,
+      qos_profile)
+  {}
 
-  RCLCPP_PUBLIC
+  template<typename NodeT>
   SyncParametersClient(
     rclcpp::Executor::SharedPtr executor,
-    rclcpp::Node * node,
+    NodeT * node,
     const std::string & remote_node_name = "",
-    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters);
+    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters)
+  : SyncParametersClient(
+      executor,
+      node->get_node_base_interface(),
+      node->get_node_topics_interface(),
+      node->get_node_graph_interface(),
+      node->get_node_services_interface(),
+      remote_node_name,
+      qos_profile)
+  {}
 
   RCLCPP_PUBLIC
   SyncParametersClient(
@@ -231,11 +368,30 @@ public:
     const rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_interface,
     const rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_interface,
     const std::string & remote_node_name = "",
-    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters);
+    const rmw_qos_profile_t & qos_profile = rmw_qos_profile_parameters)
+  : executor_(executor), node_base_interface_(node_base_interface)
+  {
+    async_parameters_client_ =
+      std::make_shared<AsyncParametersClient>(
+      node_base_interface,
+      node_topics_interface,
+      node_graph_interface,
+      node_services_interface,
+      remote_node_name,
+      qos_profile);
+  }
 
-  RCLCPP_PUBLIC
+  template<typename RepT = int64_t, typename RatioT = std::milli>
   std::vector<rclcpp::Parameter>
-  get_parameters(const std::vector<std::string> & parameter_names);
+  get_parameters(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return get_parameters(
+      parameter_names,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
 
   RCLCPP_PUBLIC
   bool
@@ -279,23 +435,107 @@ public:
     );
   }
 
-  RCLCPP_PUBLIC
+  template<typename RepT = int64_t, typename RatioT = std::milli>
+  std::vector<rcl_interfaces::msg::ParameterDescriptor>
+  describe_parameters(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return describe_parameters(
+      parameter_names,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
+
+  template<typename RepT = int64_t, typename RatioT = std::milli>
   std::vector<rclcpp::ParameterType>
-  get_parameter_types(const std::vector<std::string> & parameter_names);
+  get_parameter_types(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return get_parameter_types(
+      parameter_names,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
 
-  RCLCPP_PUBLIC
+  template<typename RepT = int64_t, typename RatioT = std::milli>
   std::vector<rcl_interfaces::msg::SetParametersResult>
-  set_parameters(const std::vector<rclcpp::Parameter> & parameters);
+  set_parameters(
+    const std::vector<rclcpp::Parameter> & parameters,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return set_parameters(
+      parameters,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
 
-  RCLCPP_PUBLIC
+  template<typename RepT = int64_t, typename RatioT = std::milli>
   rcl_interfaces::msg::SetParametersResult
-  set_parameters_atomically(const std::vector<rclcpp::Parameter> & parameters);
+  set_parameters_atomically(
+    const std::vector<rclcpp::Parameter> & parameters,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return set_parameters_atomically(
+      parameters,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
 
-  RCLCPP_PUBLIC
+  /// Delete several parameters at once.
+  /**
+   * This function behaves like command-line tool `ros2 param delete` would.
+   *
+   * \param parameters_names vector of parameters names
+   * \param timeout for the spin used to make it synchronous
+   * \return the future of the set_parameter service used to delete the parameters
+   */
+  template<typename RepT = int64_t, typename RatioT = std::milli>
+  std::vector<rcl_interfaces::msg::SetParametersResult>
+  delete_parameters(
+    const std::vector<std::string> & parameters_names,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return delete_parameters(
+      parameters_names,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
+
+  /// Load parameters from yaml file.
+  /**
+   * This function behaves like command-line tool `ros2 param load` would.
+   *
+   * \param yaml_filename the full name of the yaml file
+   * \param timeout for the spin used to make it synchronous
+   * \return the future of the set_parameter service used to load the parameters
+   */
+  template<typename RepT = int64_t, typename RatioT = std::milli>
+  std::vector<rcl_interfaces::msg::SetParametersResult>
+  load_parameters(
+    const std::string & yaml_filename,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return load_parameters(
+      yaml_filename,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
+
+  template<typename RepT = int64_t, typename RatioT = std::milli>
   rcl_interfaces::msg::ListParametersResult
   list_parameters(
     const std::vector<std::string> & parameter_prefixes,
-    uint64_t depth);
+    uint64_t depth,
+    std::chrono::duration<RepT, RatioT> timeout = std::chrono::duration<RepT, RatioT>(-1))
+  {
+    return list_parameters(
+      parameter_prefixes,
+      depth,
+      std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+    );
+  }
 
   template<typename CallbackT>
   typename rclcpp::Subscription<rcl_interfaces::msg::ParameterEvent>::SharedPtr
@@ -338,6 +578,56 @@ public:
     return async_parameters_client_->wait_for_service(timeout);
   }
 
+protected:
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::Parameter>
+  get_parameters(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  std::vector<rcl_interfaces::msg::ParameterDescriptor>
+  describe_parameters(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::ParameterType>
+  get_parameter_types(
+    const std::vector<std::string> & parameter_names,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  std::vector<rcl_interfaces::msg::SetParametersResult>
+  set_parameters(
+    const std::vector<rclcpp::Parameter> & parameters,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  std::vector<rcl_interfaces::msg::SetParametersResult>
+  delete_parameters(
+    const std::vector<std::string> & parameters_names,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  std::vector<rcl_interfaces::msg::SetParametersResult>
+  load_parameters(
+    const std::string & yaml_filename,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  rcl_interfaces::msg::SetParametersResult
+  set_parameters_atomically(
+    const std::vector<rclcpp::Parameter> & parameters,
+    std::chrono::nanoseconds timeout);
+
+  RCLCPP_PUBLIC
+  rcl_interfaces::msg::ListParametersResult
+  list_parameters(
+    const std::vector<std::string> & parameter_prefixes,
+    uint64_t depth,
+    std::chrono::nanoseconds timeout);
+
 private:
   rclcpp::Executor::SharedPtr executor_;
   const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface_;

rclcpp/include/rclcpp/parameter_event_handler.hpp

@@ -0,0 +1,347 @@
+// Copyright 2019 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__PARAMETER_EVENT_HANDLER_HPP_
+#define RCLCPP__PARAMETER_EVENT_HANDLER_HPP_
+
+#include <list>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+#include "rclcpp/create_subscription.hpp"
+#include "rclcpp/node_interfaces/get_node_base_interface.hpp"
+#include "rclcpp/node_interfaces/get_node_topics_interface.hpp"
+#include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/node_interfaces/node_topics_interface.hpp"
+#include "rclcpp/parameter.hpp"
+#include "rclcpp/qos.hpp"
+#include "rclcpp/subscription.hpp"
+#include "rclcpp/visibility_control.hpp"
+#include "rcl_interfaces/msg/parameter_event.hpp"
+
+namespace rclcpp
+{
+
+struct ParameterCallbackHandle
+{
+  RCLCPP_SMART_PTR_DEFINITIONS(ParameterCallbackHandle)
+
+  using ParameterCallbackType = std::function<void (const rclcpp::Parameter &)>;
+
+  std::string parameter_name;
+  std::string node_name;
+  ParameterCallbackType callback;
+};
+
+struct ParameterEventCallbackHandle
+{
+  RCLCPP_SMART_PTR_DEFINITIONS(ParameterEventCallbackHandle)
+
+  using ParameterEventCallbackType =
+    std::function<void (const rcl_interfaces::msg::ParameterEvent &)>;
+
+  ParameterEventCallbackType callback;
+};
+
+/// A class used to "handle" (monitor and respond to) changes to parameters.
+/**
+ * The ParameterEventHandler class allows for the monitoring of changes to node parameters,
+ * either a node's own parameters or parameters owned by other nodes in the system.
+ * Multiple parameter callbacks can be set and will be invoked when the specified parameter
+ * changes.
+ *
+ * The first step is to instantiate a ParameterEventHandler, providing a ROS node to use
+ * to create any required subscriptions:
+ *
+ *   auto param_handler = std::make_shared<rclcpp::ParameterEventHandler>(node);
+ *
+ * Next, you can supply a callback to the add_parameter_callback method, as follows:
+ *
+ *   auto cb1 = [&node](const rclcpp::Parameter & p) {
+ *      RCLCPP_INFO(
+ *        node->get_logger(),
+ *        "cb1: Received an update to parameter \"%s\" of type %s: \"%ld\"",
+ *        p.get_name().c_str(),
+ *        p.get_type_name().c_str(),
+ *        p.as_int());
+ *   };
+ *   auto handle1 = param_handler->add_parameter_callback("an_int_param", cb1);
+ *
+ * In this case, we didn't supply a node name (the third, optional, parameter) so the
+ * default will be to monitor for changes to the "an_int_param" parameter associated with
+ * the ROS node supplied in the ParameterEventHandler constructor.
+ * The callback, a lambda function in this case, simply prints out the value of the parameter.
+ *
+ * You may also monitor for changes to parameters in other nodes by supplying the node
+ * name to add_parameter_callback:
+ *
+ *   auto cb2 = [&node](const rclcpp::Parameter & p) {
+ *       RCLCPP_INFO(
+ *         node->get_logger(),
+ *         "cb2: Received an update to parameter \"%s\" of type: %s: \"%s\"",
+ *         p.get_name().c_str(),
+ *         p.get_type_name().c_str(),
+ *         p.as_string().c_str());
+ *     };
+ *   auto handle2 = param_handler->add_parameter_callback(
+ *     "some_remote_param_name", cb2, "some_remote_node_name");
+ *
+ * In this case, the callback will be invoked whenever "some_remote_param_name" changes
+ * on remote node "some_remote_node_name".
+ *
+ * To remove a parameter callback, call remove_parameter_callback, passing the handle returned
+ * from add_parameter_callback:
+ *
+ *   param_handler->remove_parameter_callback(handle2);
+ *
+ * You can also monitor for *all* parameter changes, using add_parameter_event_callback.
+ * In this case, the callback will be invoked whenever any parameter changes in the system.
+ * You are likely interested in a subset of these parameter changes, so in the callback it
+ * is convenient to use a regular expression on the node names or namespaces of interest.
+ * For example:
+ *
+ *   auto cb3 =
+ *     [fqn, remote_param_name, &node](const rcl_interfaces::msg::ParameterEvent & event) {
+ *       // Look for any updates to parameters in "/a_namespace" as well as any parameter changes
+ *       // to our own node ("this_node")
+ *       std::regex re("(/a_namespace/.*)|(/this_node)");
+ *       if (regex_match(event.node, re)) {
+ *         // Now that we know the event matches the regular expression we scanned for, we can
+ *         // use 'get_parameter_from_event' to get a specific parameter name that we're looking for
+ *         rclcpp::Parameter p;
+ *         if (rclcpp::ParameterEventsSubscriber::get_parameter_from_event(
+ *             event, p, remote_param_name, fqn))
+ *         {
+ *           RCLCPP_INFO(
+ *             node->get_logger(),
+ *             "cb3: Received an update to parameter \"%s\" of type: %s: \"%s\"",
+ *             p.get_name().c_str(),
+ *             p.get_type_name().c_str(),
+ *             p.as_string().c_str());
+ *         }
+ *
+ *         // You can also use 'get_parameter*s*_from_event' to enumerate all changes that came
+ *         // in on this event
+ *         auto params = rclcpp::ParameterEventsSubscriber::get_parameters_from_event(event);
+ *         for (auto & p : params) {
+ *           RCLCPP_INFO(
+ *             node->get_logger(),
+ *             "cb3: Received an update to parameter \"%s\" of type: %s: \"%s\"",
+ *             p.get_name().c_str(),
+ *             p.get_type_name().c_str(),
+ *             p.value_to_string().c_str());
+ *         }
+ *       }
+ *     };
+ *   auto handle3 = param_handler->add_parameter_event_callback(cb3);
+ *
+ * For both parameter callbacks and parameter event callbacks, when multiple callbacks are added,
+ * the callbacks are invoked last-in, first-called order (LIFO).
+ *
+ * To remove a parameter event callback, use:
+ *
+ *   param_handler->remove_event_parameter_callback(handle);
+ */
+class ParameterEventHandler
+{
+public:
+  /// Construct a parameter events monitor.
+  /**
+   * \param[in] node The node to use to create any required subscribers.
+   * \param[in] qos The QoS settings to use for any subscriptions.
+   */
+  template<typename NodeT>
+  explicit ParameterEventHandler(
+    NodeT node,
+    const rclcpp::QoS & qos =
+    rclcpp::QoS(rclcpp::QoSInitialization::from_rmw(rmw_qos_profile_parameter_events)))
+  : node_base_(rclcpp::node_interfaces::get_node_base_interface(node))
+  {
+    auto node_topics = rclcpp::node_interfaces::get_node_topics_interface(node);
+
+    callbacks_ = std::make_shared<Callbacks>();
+
+    event_subscription_ = rclcpp::create_subscription<rcl_interfaces::msg::ParameterEvent>(
+      node_topics, "/parameter_events", qos,
+      [callbacks = callbacks_](const rcl_interfaces::msg::ParameterEvent & event) {
+        callbacks->event_callback(event);
+      });
+  }
+
+  using ParameterEventCallbackType =
+    ParameterEventCallbackHandle::ParameterEventCallbackType;
+
+  /// Set a callback for all parameter events.
+  /**
+   * This function may be called multiple times to set multiple parameter event callbacks.
+   *
+   * \param[in] callback Function callback to be invoked on parameter updates.
+   * \returns A handle used to refer to the callback.
+   */
+  RCLCPP_PUBLIC
+  ParameterEventCallbackHandle::SharedPtr
+  add_parameter_event_callback(
+    ParameterEventCallbackType callback);
+
+  /// Remove parameter event callback registered with add_parameter_event_callback.
+  /**
+   * \param[in] callback_handle Handle of the callback to remove.
+   */
+  RCLCPP_PUBLIC
+  void
+  remove_parameter_event_callback(
+    ParameterEventCallbackHandle::SharedPtr callback_handle);
+
+  using ParameterCallbackType = ParameterCallbackHandle::ParameterCallbackType;
+
+  /// Add a callback for a specified parameter.
+  /**
+   * If a node_name is not provided, defaults to the current node.
+   *
+   * \param[in] parameter_name Name of parameter to monitor.
+   * \param[in] callback Function callback to be invoked upon parameter update.
+   * \param[in] node_name Name of node which hosts the parameter.
+   * \returns A handle used to refer to the callback.
+   */
+  RCLCPP_PUBLIC
+  ParameterCallbackHandle::SharedPtr
+  add_parameter_callback(
+    const std::string & parameter_name,
+    ParameterCallbackType callback,
+    const std::string & node_name = "");
+
+  /// Remove a parameter callback registered with add_parameter_callback.
+  /**
+   * The parameter name and node name are inspected from the callback handle. The callback handle
+   * is erased from the list of callback handles on the {parameter_name, node_name} in the map.
+   * An error is thrown if the handle does not exist and/or was already removed.
+   *
+   * \param[in] callback_handle Handle of the callback to remove.
+   */
+  RCLCPP_PUBLIC
+  void
+  remove_parameter_callback(
+    ParameterCallbackHandle::SharedPtr callback_handle);
+
+  /// Get an rclcpp::Parameter from a parameter event.
+  /**
+   * If a node_name is not provided, defaults to the current node.
+   *
+   * \param[in] event Event msg to be inspected.
+   * \param[out] parameter Reference to rclcpp::Parameter to be assigned.
+   * \param[in] parameter_name Name of parameter.
+   * \param[in] node_name Name of node which hosts the parameter.
+   * \returns Output parameter is set with requested parameter info and returns true if
+   * requested parameter name and node is in event. Otherwise, returns false.
+   */
+  RCLCPP_PUBLIC
+  static bool
+  get_parameter_from_event(
+    const rcl_interfaces::msg::ParameterEvent & event,
+    rclcpp::Parameter & parameter,
+    const std::string & parameter_name,
+    const std::string & node_name = "");
+
+  /// Get an rclcpp::Parameter from parameter event
+  /**
+   * If a node_name is not provided, defaults to the current node.
+   *
+   * The user is responsible to check if the returned parameter has been properly assigned.
+   * By default, if the requested parameter is not found in the event, the returned parameter
+   * has parameter value of type rclcpp::PARAMETER_NOT_SET.
+   *
+   * \param[in] event Event msg to be inspected.
+   * \param[in] parameter_name Name of parameter.
+   * \param[in] node_name Name of node which hosts the parameter.
+   * \returns The resultant rclcpp::Parameter from the event.
+   */
+  RCLCPP_PUBLIC
+  static rclcpp::Parameter
+  get_parameter_from_event(
+    const rcl_interfaces::msg::ParameterEvent & event,
+    const std::string & parameter_name,
+    const std::string & node_name = "");
+
+  /// Get all rclcpp::Parameter values from a parameter event
+  /**
+   * \param[in] event Event msg to be inspected.
+   * \returns A vector rclcpp::Parameter values from the event.
+   */
+  RCLCPP_PUBLIC
+  static std::vector<rclcpp::Parameter>
+  get_parameters_from_event(
+    const rcl_interfaces::msg::ParameterEvent & event);
+
+  using CallbacksContainerType = std::list<ParameterCallbackHandle::WeakPtr>;
+
+protected:
+  // *INDENT-OFF* Uncrustify doesn't handle indented public/private labels
+  // Hash function for string pair required in std::unordered_map
+  // See: https://stackoverflow.com/questions/35985960/c-why-is-boosthash-combine-the-best-way-to-combine-hash-values
+  class StringPairHash
+  {
+  public:
+    template<typename T>
+    inline void hash_combine(std::size_t & seed, const T & v) const
+    {
+      std::hash<T> hasher;
+      seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+    }
+
+    inline size_t operator()(const std::pair<std::string, std::string> & s) const
+    {
+      size_t seed = 0;
+      hash_combine(seed, s.first);
+      hash_combine(seed, s.second);
+      return seed;
+    }
+  };
+  // *INDENT-ON*
+
+  struct Callbacks
+  {
+    std::recursive_mutex mutex_;
+
+    // Map container for registered parameters
+    std::unordered_map<
+      std::pair<std::string, std::string>,
+      CallbacksContainerType,
+      StringPairHash
+    > parameter_callbacks_;
+
+    std::list<ParameterEventCallbackHandle::WeakPtr> event_callbacks_;
+
+    /// Callback for parameter events subscriptions.
+    RCLCPP_PUBLIC
+    void
+    event_callback(const rcl_interfaces::msg::ParameterEvent & event);
+  };
+
+  std::shared_ptr<Callbacks> callbacks_;
+
+  // Utility function for resolving node path.
+  std::string resolve_path(const std::string & path);
+
+  // Node interface used for base functionality
+  std::shared_ptr<rclcpp::node_interfaces::NodeBaseInterface> node_base_;
+
+  rclcpp::Subscription<rcl_interfaces::msg::ParameterEvent>::SharedPtr event_subscription_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__PARAMETER_EVENT_HANDLER_HPP_

rclcpp/include/rclcpp/parameter_events_filter.hpp

@@ -37,7 +37,7 @@ public:
   RCLCPP_SMART_PTR_DEFINITIONS(ParameterEventsFilter)
   enum class EventType {NEW, DELETED, CHANGED};  ///< An enum for the type of event.
   /// Used for the listed results
-  using EventPair = std::pair<EventType, rcl_interfaces::msg::Parameter *>;
+  using EventPair = std::pair<EventType, const rcl_interfaces::msg::Parameter *>;
 
   /// Construct a filtered view of a parameter event.
   /**
@@ -60,7 +60,7 @@ public:
    */
   RCLCPP_PUBLIC
   ParameterEventsFilter(
-    rcl_interfaces::msg::ParameterEvent::SharedPtr event,
+    std::shared_ptr<const rcl_interfaces::msg::ParameterEvent> event,
     const std::vector<std::string> & names,
     const std::vector<EventType> & types);
 
@@ -74,7 +74,7 @@ public:
 private:
   // access only allowed via const accessor.
   std::vector<EventPair> result_;  ///< Storage of the resultant vector
-  rcl_interfaces::msg::ParameterEvent::SharedPtr event_;  ///< Keep event in scope
+  std::shared_ptr<const rcl_interfaces::msg::ParameterEvent> event_;  ///< Keep event in scope
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/parameter_map.hpp

@@ -15,6 +15,7 @@
 #ifndef RCLCPP__PARAMETER_MAP_HPP_
 #define RCLCPP__PARAMETER_MAP_HPP_
 
+#include <rcl_yaml_param_parser/parser.h>
 #include <rcl_yaml_param_parser/types.h>
 
 #include <string>
@@ -40,6 +41,16 @@ RCLCPP_PUBLIC
 ParameterMap
 parameter_map_from(const rcl_params_t * const c_params);
 
+/// Convert parameters from rcl_yaml_param_parser into C++ class instances.
+/// \param[in] c_params C structures containing parameters for multiple nodes.
+/// \param[in] node_fqn a Fully Qualified Name of node, default value is nullptr.
+///   If it's not nullptr, return the relative node parameters belonging to this node_fqn.
+/// \returns a map where the keys are fully qualified node names and values a list of parameters.
+/// \throws InvalidParametersException if the `rcl_params_t` is inconsistent or invalid.
+RCLCPP_PUBLIC
+ParameterMap
+parameter_map_from(const rcl_params_t * const c_params, const char * node_fqn);
+
 /// Convert parameter value from rcl_yaml_param_parser into a C++ class instance.
 /// \param[in] c_value C structure containing a value of a parameter.
 /// \returns an instance of a parameter value
@@ -48,6 +59,14 @@ RCLCPP_PUBLIC
 ParameterValue
 parameter_value_from(const rcl_variant_t * const c_value);
 
+/// Get the ParameterMap from a yaml file.
+/// \param[in] yaml_filename full name of the yaml file.
+/// \returns an instance of a parameter map
+/// \throws from rcl error of rcl_parse_yaml_file()
+RCLCPP_PUBLIC
+ParameterMap
+parameter_map_from_yaml_file(const std::string & yaml_filename);
+
 }  // namespace rclcpp
 
 #endif  // RCLCPP__PARAMETER_MAP_HPP_

rclcpp/include/rclcpp/parameter_value.hpp

@@ -301,6 +301,16 @@ public:
     return get<ParameterType::PARAMETER_BOOL_ARRAY>();
   }
 
+  template<typename type>
+  constexpr
+  typename std::enable_if<
+    std::is_convertible<
+      type, const std::vector<int> &>::value, const std::vector<int64_t> &>::type
+  get() const
+  {
+    return get<ParameterType::PARAMETER_INTEGER_ARRAY>();
+  }
+
   template<typename type>
   constexpr
   typename std::enable_if<
@@ -311,6 +321,16 @@ public:
     return get<ParameterType::PARAMETER_INTEGER_ARRAY>();
   }
 
+  template<typename type>
+  constexpr
+  typename std::enable_if<
+    std::is_convertible<
+      type, const std::vector<float> &>::value, const std::vector<double> &>::type
+  get() const
+  {
+    return get<ParameterType::PARAMETER_DOUBLE_ARRAY>();
+  }
+
   template<typename type>
   constexpr
   typename std::enable_if<

rclcpp/include/rclcpp/publisher.hpp

@@ -15,31 +15,37 @@
 #ifndef RCLCPP__PUBLISHER_HPP_
 #define RCLCPP__PUBLISHER_HPP_
 
-#include <rmw/error_handling.h>
-#include <rmw/rmw.h>
-
 #include <functional>
 #include <iostream>
 #include <memory>
 #include <sstream>
 #include <string>
+#include <type_traits>
 #include <utility>
 
 #include "rcl/error_handling.h"
 #include "rcl/publisher.h"
+#include "rmw/error_handling.h"
+#include "rmw/rmw.h"
+#include "rosidl_runtime_cpp/traits.hpp"
 
 #include "rclcpp/allocator/allocator_common.hpp"
 #include "rclcpp/allocator/allocator_deleter.hpp"
 #include "rclcpp/detail/resolve_use_intra_process.hpp"
 #include "rclcpp/experimental/intra_process_manager.hpp"
+#include "rclcpp/get_message_type_support_handle.hpp"
+#include "rclcpp/is_ros_compatible_type.hpp"
 #include "rclcpp/loaned_message.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_base_interface.hpp"
 #include "rclcpp/publisher_base.hpp"
 #include "rclcpp/publisher_options.hpp"
+#include "rclcpp/type_adapter.hpp"
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/visibility_control.hpp"
 
+#include "tracetools/tracetools.h"
+
 namespace rclcpp
 {
 
@@ -47,18 +53,75 @@ template<typename MessageT, typename AllocatorT>
 class LoanedMessage;
 
 /// A publisher publishes messages of any type to a topic.
+/**
+ * MessageT must be a:
+ *
+ * - ROS message type with its own type support (e.g. std_msgs::msgs::String), or a
+ * - rclcpp::TypeAdapter<CustomType, ROSMessageType>
+ *   (e.g. rclcpp::TypeAdapter<std::string, std_msgs::msg::String), or a
+ * - custom type that has been setup as the implicit type for a ROS type using
+ *   RCLCPP_USING_CUSTOM_TYPE_AS_ROS_MESSAGE_TYPE(custom_type, ros_message_type)
+ *
+ * In the case that MessageT is ROS message type (e.g. std_msgs::msg::String),
+ * both PublishedType and ROSMessageType will be that type.
+ * In the case that MessageT is a TypeAdapter<CustomType, ROSMessageType> type
+ * (e.g. TypeAdapter<std::string, std_msgs::msg::String>), PublishedType will
+ * be the custom type, and ROSMessageType will be the ros message type.
+ *
+ * This is achieved because of the "identity specialization" for TypeAdapter,
+ * which returns itself if it is already a TypeAdapter, and the default
+ * specialization which allows ROSMessageType to be void.
+ * \sa rclcpp::TypeAdapter for more details.
+ */
 template<typename MessageT, typename AllocatorT = std::allocator<void>>
 class Publisher : public PublisherBase
 {
 public:
-  using MessageAllocatorTraits = allocator::AllocRebind<MessageT, AllocatorT>;
-  using MessageAllocator = typename MessageAllocatorTraits::allocator_type;
-  using MessageDeleter = allocator::Deleter<MessageAllocator, MessageT>;
-  using MessageUniquePtr = std::unique_ptr<MessageT, MessageDeleter>;
-  using MessageSharedPtr = std::shared_ptr<const MessageT>;
+  static_assert(
+    rclcpp::is_ros_compatible_type<MessageT>::value,
+    "given message type is not compatible with ROS and cannot be used with a Publisher");
+
+  /// MessageT::custom_type if MessageT is a TypeAdapter, otherwise just MessageT.
+  using PublishedType = typename rclcpp::TypeAdapter<MessageT>::custom_type;
+  using ROSMessageType = typename rclcpp::TypeAdapter<MessageT>::ros_message_type;
+
+  using PublishedTypeAllocatorTraits = allocator::AllocRebind<PublishedType, AllocatorT>;
+  using PublishedTypeAllocator = typename PublishedTypeAllocatorTraits::allocator_type;
+  using PublishedTypeDeleter = allocator::Deleter<PublishedTypeAllocator, PublishedType>;
+
+  using ROSMessageTypeAllocatorTraits = allocator::AllocRebind<ROSMessageType, AllocatorT>;
+  using ROSMessageTypeAllocator = typename ROSMessageTypeAllocatorTraits::allocator_type;
+  using ROSMessageTypeDeleter = allocator::Deleter<ROSMessageTypeAllocator, ROSMessageType>;
+
+  using MessageAllocatorTraits
+  [[deprecated("use PublishedTypeAllocatorTraits")]] =
+    PublishedTypeAllocatorTraits;
+  using MessageAllocator
+  [[deprecated("use PublishedTypeAllocator")]] =
+    PublishedTypeAllocator;
+  using MessageDeleter
+  [[deprecated("use PublishedTypeDeleter")]] =
+    PublishedTypeDeleter;
+  using MessageUniquePtr
+  [[deprecated("use std::unique_ptr<PublishedType, PublishedTypeDeleter>")]] =
+    std::unique_ptr<PublishedType, PublishedTypeDeleter>;
+  using MessageSharedPtr
+  [[deprecated("use std::shared_ptr<const PublishedType>")]] =
+    std::shared_ptr<const PublishedType>;
 
   RCLCPP_SMART_PTR_DEFINITIONS(Publisher<MessageT, AllocatorT>)
 
+  /// Default constructor.
+  /**
+   * The constructor for a Publisher is almost never called directly.
+   * Instead, subscriptions should be instantiated through the function
+   * rclcpp::create_publisher().
+   *
+   * \param[in] node_base NodeBaseInterface pointer that is used in part of the setup.
+   * \param[in] topic Name of the topic to publish to.
+   * \param[in] qos QoS profile for Subcription.
+   * \param[in] options Options for the subscription.
+   */
   Publisher(
     rclcpp::node_interfaces::NodeBaseInterface * node_base,
     const std::string & topic,
@@ -67,12 +130,14 @@ public:
   : PublisherBase(
       node_base,
       topic,
-      *rosidl_typesupport_cpp::get_message_type_support_handle<MessageT>(),
+      rclcpp::get_message_type_support_handle<MessageT>(),
       options.template to_rcl_publisher_options<MessageT>(qos)),
     options_(options),
-    message_allocator_(new MessageAllocator(*options.get_allocator().get()))
+    published_type_allocator_(*options.get_allocator()),
+    ros_message_type_allocator_(*options.get_allocator())
   {
-    allocator::set_allocator_for_deleter(&message_deleter_, message_allocator_.get());
+    allocator::set_allocator_for_deleter(&published_type_deleter_, &published_type_allocator_);
+    allocator::set_allocator_for_deleter(&ros_message_type_deleter_, &ros_message_type_allocator_);
 
     if (options_.event_callbacks.deadline_callback) {
       this->add_event_handler(
@@ -112,8 +177,7 @@ public:
     const rclcpp::QoS & qos,
     const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options)
   {
-    // Topic is unused for now.
-    (void)topic;
+    (void)qos;
     (void)options;
 
     // If needed, setup intra process communication.
@@ -121,19 +185,23 @@ public:
       auto context = node_base->get_context();
       // Get the intra process manager instance for this context.
       auto ipm = context->get_sub_context<rclcpp::experimental::IntraProcessManager>();
-      // Register the publisher with the intra process manager.
-      if (qos.get_rmw_qos_profile().history == RMW_QOS_POLICY_HISTORY_KEEP_ALL) {
+      // Check if the QoS is compatible with intra-process.
+      auto qos_profile = get_actual_qos();
+      if (qos_profile.history() != rclcpp::HistoryPolicy::KeepLast) {
         throw std::invalid_argument(
-                "intraprocess communication is not allowed with keep all history qos policy");
+                "intraprocess communication on topic '" + topic +
+                "' allowed only with keep last history qos policy");
       }
-      if (qos.get_rmw_qos_profile().depth == 0) {
+      if (qos_profile.depth() == 0) {
         throw std::invalid_argument(
-                "intraprocess communication is not allowed with a zero qos history depth value");
+                "intraprocess communication on topic '" + topic +
+                "' is not allowed with a zero qos history depth value");
       }
-      if (qos.get_rmw_qos_profile().durability != RMW_QOS_POLICY_DURABILITY_VOLATILE) {
+      if (qos_profile.durability() != rclcpp::DurabilityPolicy::Volatile) {
         throw std::invalid_argument(
                 "intraprocess communication allowed only with volatile durability");
       }
+      // Register the publisher with the intra process manager.
       uint64_t intra_process_publisher_id = ipm->add_publisher(this->shared_from_this());
       this->setup_intra_process(
         intra_process_publisher_id,
@@ -157,21 +225,33 @@ public:
    * allocator.
    * \sa rclcpp::LoanedMessage for details of the LoanedMessage class.
    *
-   * \return LoanedMessage containing memory for a ROS message of type MessageT
+   * \return LoanedMessage containing memory for a ROS message of type ROSMessageType
    */
-  rclcpp::LoanedMessage<MessageT, AllocatorT>
+  rclcpp::LoanedMessage<ROSMessageType, AllocatorT>
   borrow_loaned_message()
   {
-    return rclcpp::LoanedMessage<MessageT, AllocatorT>(this, this->get_allocator());
+    return rclcpp::LoanedMessage<ROSMessageType, AllocatorT>(
+      *this,
+      this->get_ros_message_type_allocator());
   }
 
-  /// Send a message to the topic for this publisher.
+  /// Publish a message on the topic.
   /**
-   * This function is templated on the input message type, MessageT.
-   * \param[in] msg A shared pointer to the message to send.
+   * This signature is enabled if the element_type of the std::unique_ptr is
+   * a ROS message type, as opposed to the custom_type of a TypeAdapter, and
+   * that type matches the type given when creating the publisher.
+   *
+   * This signature allows the user to give ownership of the message to rclcpp,
+   * allowing for more efficient intra-process communication optimizations.
+   *
+   * \param[in] msg A unique pointer to the message to send.
    */
-  virtual void
-  publish(std::unique_ptr<MessageT, MessageDeleter> msg)
+  template<typename T>
+  typename std::enable_if_t<
+    rosidl_generator_traits::is_message<T>::value &&
+    std::is_same<T, ROSMessageType>::value
+  >
+  publish(std::unique_ptr<T, ROSMessageTypeDeleter> msg)
   {
     if (!intra_process_is_enabled_) {
       this->do_inter_process_publish(*msg);
@@ -187,15 +267,32 @@ public:
       get_subscription_count() > get_intra_process_subscription_count();
 
     if (inter_process_publish_needed) {
-      auto shared_msg = this->do_intra_process_publish_and_return_shared(std::move(msg));
+      auto shared_msg =
+        this->do_intra_process_ros_message_publish_and_return_shared(std::move(msg));
       this->do_inter_process_publish(*shared_msg);
     } else {
-      this->do_intra_process_publish(std::move(msg));
+      this->do_intra_process_ros_message_publish(std::move(msg));
     }
   }
 
-  virtual void
-  publish(const MessageT & msg)
+  /// Publish a message on the topic.
+  /**
+   * This signature is enabled if the object being published is
+   * a ROS message type, as opposed to the custom_type of a TypeAdapter, and
+   * that type matches the type given when creating the publisher.
+   *
+   * This signature allows the user to give a reference to a message, which is
+   * copied onto the heap without modification so that a copy can be owned by
+   * rclcpp and ownership of the copy can be moved later if needed.
+   *
+   * \param[in] msg A const reference to the message to send.
+   */
+  template<typename T>
+  typename std::enable_if_t<
+    rosidl_generator_traits::is_message<T>::value &&
+    std::is_same<T, ROSMessageType>::value
+  >
+  publish(const T & msg)
   {
     // Avoid allocating when not using intra process.
     if (!intra_process_is_enabled_) {
@@ -205,9 +302,83 @@ public:
     // Otherwise we have to allocate memory in a unique_ptr and pass it along.
     // As the message is not const, a copy should be made.
     // A shared_ptr<const MessageT> could also be constructed here.
-    auto ptr = MessageAllocatorTraits::allocate(*message_allocator_.get(), 1);
-    MessageAllocatorTraits::construct(*message_allocator_.get(), ptr, msg);
-    MessageUniquePtr unique_msg(ptr, message_deleter_);
+    auto unique_msg = this->duplicate_ros_message_as_unique_ptr(msg);
+    this->publish(std::move(unique_msg));
+  }
+
+  /// Publish a message on the topic.
+  /**
+   * This signature is enabled if this class was created with a TypeAdapter and
+   * the element_type of the std::unique_ptr matches the custom_type for the
+   * TypeAdapter used with this class.
+   *
+   * This signature allows the user to give ownership of the message to rclcpp,
+   * allowing for more efficient intra-process communication optimizations.
+   *
+   * \param[in] msg A unique pointer to the message to send.
+   */
+  template<typename T>
+  typename std::enable_if_t<
+    rclcpp::TypeAdapter<MessageT>::is_specialized::value &&
+    std::is_same<T, PublishedType>::value
+  >
+  publish(std::unique_ptr<T, PublishedTypeDeleter> msg)
+  {
+    // Avoid allocating when not using intra process.
+    if (!intra_process_is_enabled_) {
+      // In this case we're not using intra process.
+      ROSMessageType ros_msg;
+      rclcpp::TypeAdapter<MessageT>::convert_to_ros_message(*msg, ros_msg);
+      return this->do_inter_process_publish(ros_msg);
+    }
+
+    bool inter_process_publish_needed =
+      get_subscription_count() > get_intra_process_subscription_count();
+
+    if (inter_process_publish_needed) {
+      ROSMessageType ros_msg;
+      // TODO(clalancette): This is unnecessarily doing an additional conversion
+      // that may have already been done in do_intra_process_publish_and_return_shared().
+      // We should just reuse that effort.
+      rclcpp::TypeAdapter<MessageT>::convert_to_ros_message(*msg, ros_msg);
+      this->do_intra_process_publish(std::move(msg));
+      this->do_inter_process_publish(ros_msg);
+    } else {
+      this->do_intra_process_publish(std::move(msg));
+    }
+  }
+
+  /// Publish a message on the topic.
+  /**
+   * This signature is enabled if this class was created with a TypeAdapter and
+   * the given type matches the custom_type of the TypeAdapter.
+   *
+   * This signature allows the user to give a reference to a message, which is
+   * copied onto the heap without modification so that a copy can be owned by
+   * rclcpp and ownership of the copy can be moved later if needed.
+   *
+   * \param[in] msg A const reference to the message to send.
+   */
+  template<typename T>
+  typename std::enable_if_t<
+    rclcpp::TypeAdapter<MessageT>::is_specialized::value &&
+    std::is_same<T, PublishedType>::value
+  >
+  publish(const T & msg)
+  {
+    // Avoid double allocating when not using intra process.
+    if (!intra_process_is_enabled_) {
+      // Convert to the ROS message equivalent and publish it.
+      ROSMessageType ros_msg;
+      rclcpp::TypeAdapter<MessageT>::convert_to_ros_message(msg, ros_msg);
+      // In this case we're not using intra process.
+      return this->do_inter_process_publish(ros_msg);
+    }
+
+    // Otherwise we have to allocate memory in a unique_ptr and pass it along.
+    // As the message is not const, a copy should be made.
+    // A shared_ptr<const MessageT> could also be constructed here.
+    auto unique_msg = this->duplicate_type_adapt_message_as_unique_ptr(msg);
     this->publish(std::move(unique_msg));
   }
 
@@ -217,6 +388,12 @@ public:
     return this->do_serialized_publish(&serialized_msg);
   }
 
+  void
+  publish(const SerializedMessage & serialized_msg)
+  {
+    return this->do_serialized_publish(&serialized_msg.get_rcl_serialized_message());
+  }
+
   /// Publish an instance of a LoanedMessage.
   /**
    * When publishing a loaned message, the memory for this ROS message will be deallocated
@@ -226,7 +403,7 @@ public:
    * \param loaned_msg The LoanedMessage instance to be published.
    */
   void
-  publish(rclcpp::LoanedMessage<MessageT, AllocatorT> && loaned_msg)
+  publish(rclcpp::LoanedMessage<ROSMessageType, AllocatorT> && loaned_msg)
   {
     if (!loaned_msg.is_valid()) {
       throw std::runtime_error("loaned message is not valid");
@@ -244,7 +421,7 @@ public:
     if (this->can_loan_messages()) {
       // we release the ownership from the rclpp::LoanedMessage instance
       // and let the middleware clean up the memory.
-      this->do_loaned_message_publish(loaned_msg.release());
+      this->do_loaned_message_publish(std::move(loaned_msg.release()));
     } else {
       // we don't release the ownership, let the middleware copy the ros message
       // and thus the destructor of rclcpp::LoanedMessage cleans up the memory.
@@ -252,22 +429,36 @@ public:
     }
   }
 
-  std::shared_ptr<MessageAllocator>
+  [[deprecated("use get_published_type_allocator() or get_ros_message_type_allocator() instead")]]
+  std::shared_ptr<PublishedTypeAllocator>
   get_allocator() const
   {
-    return message_allocator_;
+    return std::make_shared<PublishedTypeAllocator>(published_type_allocator_);
+  }
+
+  PublishedTypeAllocator
+  get_published_type_allocator() const
+  {
+    return published_type_allocator_;
+  }
+
+  ROSMessageTypeAllocator
+  get_ros_message_type_allocator() const
+  {
+    return ros_message_type_allocator_;
   }
 
 protected:
   void
-  do_inter_process_publish(const MessageT & msg)
+  do_inter_process_publish(const ROSMessageType & msg)
   {
-    auto status = rcl_publish(&publisher_handle_, &msg, nullptr);
+    TRACEPOINT(rclcpp_publish, nullptr, static_cast<const void *>(&msg));
+    auto status = rcl_publish(publisher_handle_.get(), &msg, nullptr);
 
     if (RCL_RET_PUBLISHER_INVALID == status) {
       rcl_reset_error();  // next call will reset error message if not context
-      if (rcl_publisher_is_valid_except_context(&publisher_handle_)) {
-        rcl_context_t * context = rcl_publisher_get_context(&publisher_handle_);
+      if (rcl_publisher_is_valid_except_context(publisher_handle_.get())) {
+        rcl_context_t * context = rcl_publisher_get_context(publisher_handle_.get());
         if (nullptr != context && !rcl_context_is_valid(context)) {
           // publisher is invalid due to context being shutdown
           return;
@@ -286,21 +477,22 @@ protected:
       // TODO(Karsten1987): support serialized message passed by intraprocess
       throw std::runtime_error("storing serialized messages in intra process is not supported yet");
     }
-    auto status = rcl_publish_serialized_message(&publisher_handle_, serialized_msg, nullptr);
+    auto status = rcl_publish_serialized_message(publisher_handle_.get(), serialized_msg, nullptr);
     if (RCL_RET_OK != status) {
       rclcpp::exceptions::throw_from_rcl_error(status, "failed to publish serialized message");
     }
   }
 
   void
-  do_loaned_message_publish(MessageT * msg)
+  do_loaned_message_publish(
+    std::unique_ptr<ROSMessageType, std::function<void(ROSMessageType *)>> msg)
   {
-    auto status = rcl_publish_loaned_message(&publisher_handle_, msg, nullptr);
+    auto status = rcl_publish_loaned_message(publisher_handle_.get(), msg.get(), nullptr);
 
     if (RCL_RET_PUBLISHER_INVALID == status) {
       rcl_reset_error();  // next call will reset error message if not context
-      if (rcl_publisher_is_valid_except_context(&publisher_handle_)) {
-        rcl_context_t * context = rcl_publisher_get_context(&publisher_handle_);
+      if (rcl_publisher_is_valid_except_context(publisher_handle_.get())) {
+        rcl_context_t * context = rcl_publisher_get_context(publisher_handle_.get());
         if (nullptr != context && !rcl_context_is_valid(context)) {
           // publisher is invalid due to context being shutdown
           return;
@@ -313,7 +505,7 @@ protected:
   }
 
   void
-  do_intra_process_publish(std::unique_ptr<MessageT, MessageDeleter> msg)
+  do_intra_process_publish(std::unique_ptr<PublishedType, PublishedTypeDeleter> msg)
   {
     auto ipm = weak_ipm_.lock();
     if (!ipm) {
@@ -324,14 +516,14 @@ protected:
       throw std::runtime_error("cannot publish msg which is a null pointer");
     }
 
-    ipm->template do_intra_process_publish<MessageT, AllocatorT>(
+    ipm->template do_intra_process_publish<PublishedType, ROSMessageType, AllocatorT>(
       intra_process_publisher_id_,
       std::move(msg),
-      message_allocator_);
+      published_type_allocator_);
   }
 
-  std::shared_ptr<const MessageT>
-  do_intra_process_publish_and_return_shared(std::unique_ptr<MessageT, MessageDeleter> msg)
+  void
+  do_intra_process_ros_message_publish(std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter> msg)
   {
     auto ipm = weak_ipm_.lock();
     if (!ipm) {
@@ -342,10 +534,58 @@ protected:
       throw std::runtime_error("cannot publish msg which is a null pointer");
     }
 
-    return ipm->template do_intra_process_publish_and_return_shared<MessageT, AllocatorT>(
+    ipm->template do_intra_process_publish<ROSMessageType, ROSMessageType, AllocatorT>(
       intra_process_publisher_id_,
       std::move(msg),
-      message_allocator_);
+      ros_message_type_allocator_);
+  }
+
+  std::shared_ptr<const ROSMessageType>
+  do_intra_process_ros_message_publish_and_return_shared(
+    std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter> msg)
+  {
+    auto ipm = weak_ipm_.lock();
+    if (!ipm) {
+      throw std::runtime_error(
+              "intra process publish called after destruction of intra process manager");
+    }
+    if (!msg) {
+      throw std::runtime_error("cannot publish msg which is a null pointer");
+    }
+
+    return ipm->template do_intra_process_publish_and_return_shared<ROSMessageType, ROSMessageType,
+             AllocatorT>(
+      intra_process_publisher_id_,
+      std::move(msg),
+      ros_message_type_allocator_);
+  }
+
+
+  /// Return a new unique_ptr using the ROSMessageType of the publisher.
+  std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>
+  create_ros_message_unique_ptr()
+  {
+    auto ptr = ROSMessageTypeAllocatorTraits::allocate(ros_message_type_allocator_, 1);
+    ROSMessageTypeAllocatorTraits::construct(ros_message_type_allocator_, ptr);
+    return std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>(ptr, ros_message_type_deleter_);
+  }
+
+  /// Duplicate a given ros message as a unique_ptr.
+  std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>
+  duplicate_ros_message_as_unique_ptr(const ROSMessageType & msg)
+  {
+    auto ptr = ROSMessageTypeAllocatorTraits::allocate(ros_message_type_allocator_, 1);
+    ROSMessageTypeAllocatorTraits::construct(ros_message_type_allocator_, ptr, msg);
+    return std::unique_ptr<ROSMessageType, ROSMessageTypeDeleter>(ptr, ros_message_type_deleter_);
+  }
+
+  /// Duplicate a given type adapted message as a unique_ptr.
+  std::unique_ptr<PublishedType, PublishedTypeDeleter>
+  duplicate_type_adapt_message_as_unique_ptr(const PublishedType & msg)
+  {
+    auto ptr = PublishedTypeAllocatorTraits::allocate(published_type_allocator_, 1);
+    PublishedTypeAllocatorTraits::construct(published_type_allocator_, ptr, msg);
+    return std::unique_ptr<PublishedType, PublishedTypeDeleter>(ptr, published_type_deleter_);
   }
 
   /// Copy of original options passed during construction.
@@ -355,9 +595,10 @@ protected:
    */
   const rclcpp::PublisherOptionsWithAllocator<AllocatorT> options_;
 
-  std::shared_ptr<MessageAllocator> message_allocator_;
-
-  MessageDeleter message_deleter_;
+  PublishedTypeAllocator published_type_allocator_;
+  PublishedTypeDeleter published_type_deleter_;
+  ROSMessageTypeAllocator ros_message_type_allocator_;
+  ROSMessageTypeDeleter ros_message_type_deleter_;
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/publisher_base.hpp

@@ -18,20 +18,25 @@
 #include <rmw/error_handling.h>
 #include <rmw/rmw.h>
 
+#include <chrono>
 #include <functional>
 #include <iostream>
 #include <memory>
 #include <sstream>
 #include <string>
+#include <unordered_map>
+#include <utility>
 #include <vector>
 
 #include "rcl/publisher.h"
 
 #include "rclcpp/macros.hpp"
+#include "rclcpp/network_flow_endpoint.hpp"
 #include "rclcpp/qos.hpp"
 #include "rclcpp/qos_event.hpp"
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/visibility_control.hpp"
+#include "rcpputils/time.hpp"
 
 namespace rclcpp
 {
@@ -99,19 +104,20 @@ public:
   /// Get the rcl publisher handle.
   /** \return The rcl publisher handle. */
   RCLCPP_PUBLIC
-  rcl_publisher_t *
+  std::shared_ptr<rcl_publisher_t>
   get_publisher_handle();
 
   /// Get the rcl publisher handle.
   /** \return The rcl publisher handle. */
   RCLCPP_PUBLIC
-  const rcl_publisher_t *
+  std::shared_ptr<const rcl_publisher_t>
   get_publisher_handle() const;
 
   /// Get all the QoS event handlers associated with this publisher.
-  /** \return The vector of QoS event handlers. */
+  /** \return The map of QoS event handlers. */
   RCLCPP_PUBLIC
-  const std::vector<std::shared_ptr<rclcpp::QOSEventHandlerBase>> &
+  const
+  std::unordered_map<rcl_publisher_event_type_t, std::shared_ptr<rclcpp::QOSEventHandlerBase>> &
   get_event_handlers() const;
 
   /// Get subscription count
@@ -193,6 +199,120 @@ public:
     uint64_t intra_process_publisher_id,
     IntraProcessManagerSharedPtr ipm);
 
+  /// Get network flow endpoints
+  /**
+   * Describes network flow endpoints that this publisher is sending messages out on
+   * \return vector of NetworkFlowEndpoint
+   */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::NetworkFlowEndpoint>
+  get_network_flow_endpoints() const;
+
+  /// Wait until all published messages are acknowledged or until the specified timeout elapses.
+  /**
+   * This method waits until all published messages are acknowledged by all matching
+   * subscriptions or the given timeout elapses.
+   *
+   * If the timeout is negative then this method will block indefinitely until all published
+   * messages are acknowledged.
+   * If the timeout is zero then this method will not block, it will check if all published
+   * messages are acknowledged and return immediately.
+   * If the timeout is greater than zero, this method will wait until all published messages are
+   * acknowledged or the timeout elapses.
+   *
+   * This method only waits for acknowledgments if the publisher's QoS profile is RELIABLE.
+   * Otherwise this method will immediately return `true`.
+   *
+   * \param[in] timeout the duration to wait for all published messages to be acknowledged.
+   * \return `true` if all published messages were acknowledged before the given timeout
+   *   elapsed, otherwise `false`.
+   * \throws rclcpp::exceptions::RCLError if middleware doesn't support or internal error occurs
+   * \throws std::invalid_argument if timeout is greater than std::chrono::nanoseconds::max() or
+   *   less than std::chrono::nanoseconds::min()
+   */
+  template<typename DurationRepT = int64_t, typename DurationT = std::milli>
+  bool
+  wait_for_all_acked(
+    std::chrono::duration<DurationRepT, DurationT> timeout =
+    std::chrono::duration<DurationRepT, DurationT>(-1)) const
+  {
+    rcl_duration_value_t rcl_timeout = rcpputils::convert_to_nanoseconds(timeout).count();
+
+    rcl_ret_t ret = rcl_publisher_wait_for_all_acked(publisher_handle_.get(), rcl_timeout);
+    if (ret == RCL_RET_OK) {
+      return true;
+    } else if (ret == RCL_RET_TIMEOUT) {
+      return false;
+    } else {
+      rclcpp::exceptions::throw_from_rcl_error(ret);
+    }
+  }
+
+  /// Set a callback to be called when each new qos event instance occurs.
+  /**
+   * The callback receives a size_t which is the number of events that occurred
+   * since the last time this callback was called.
+   * Normally this is 1, but can be > 1 if events occurred before any
+   * callback was set.
+   *
+   * Since this callback is called from the middleware, you should aim to make
+   * it fast and not blocking.
+   * If you need to do a lot of work or wait for some other event, you should
+   * spin it off to another thread, otherwise you risk blocking the middleware.
+   *
+   * Calling it again will clear any previously set callback.
+   *
+   * An exception will be thrown if the callback is not callable.
+   *
+   * This function is thread-safe.
+   *
+   * If you want more information available in the callback, like the qos event
+   * or other information, you may use a lambda with captures or std::bind.
+   *
+   * \sa rclcpp::QOSEventHandlerBase::set_on_ready_callback
+   *
+   * \param[in] callback functor to be called when a new event occurs
+   * \param[in] event_type identifier for the qos event we want to attach the callback to
+   */
+  void
+  set_on_new_qos_event_callback(
+    std::function<void(size_t)> callback,
+    rcl_publisher_event_type_t event_type)
+  {
+    if (event_handlers_.count(event_type) == 0) {
+      RCLCPP_WARN(
+        rclcpp::get_logger("rclcpp"),
+        "Calling set_on_new_qos_event_callback for non registered publisher event_type");
+      return;
+    }
+
+    if (!callback) {
+      throw std::invalid_argument(
+              "The callback passed to set_on_new_qos_event_callback "
+              "is not callable.");
+    }
+
+    // The on_ready_callback signature has an extra `int` argument used to disambiguate between
+    // possible different entities within a generic waitable.
+    // We hide that detail to users of this method.
+    std::function<void(size_t, int)> new_callback = std::bind(callback, std::placeholders::_1);
+    event_handlers_[event_type]->set_on_ready_callback(new_callback);
+  }
+
+  /// Unset the callback registered for new qos events, if any.
+  void
+  clear_on_new_qos_event_callback(rcl_publisher_event_type_t event_type)
+  {
+    if (event_handlers_.count(event_type) == 0) {
+      RCLCPP_WARN(
+        rclcpp::get_logger("rclcpp"),
+        "Calling clear_on_new_qos_event_callback for non registered event_type");
+      return;
+    }
+
+    event_handlers_[event_type]->clear_on_ready_callback();
+  }
+
 protected:
   template<typename EventCallbackT>
   void
@@ -200,12 +320,13 @@ protected:
     const EventCallbackT & callback,
     const rcl_publisher_event_type_t event_type)
   {
-    auto handler = std::make_shared<QOSEventHandler<EventCallbackT>>(
+    auto handler = std::make_shared<QOSEventHandler<EventCallbackT,
+        std::shared_ptr<rcl_publisher_t>>>(
       callback,
       rcl_publisher_event_init,
-      &publisher_handle_,
+      publisher_handle_,
       event_type);
-    event_handlers_.emplace_back(handler);
+    event_handlers_.insert(std::make_pair(event_type, handler));
   }
 
   RCLCPP_PUBLIC
@@ -213,9 +334,10 @@ protected:
 
   std::shared_ptr<rcl_node_t> rcl_node_handle_;
 
-  rcl_publisher_t publisher_handle_ = rcl_get_zero_initialized_publisher();
+  std::shared_ptr<rcl_publisher_t> publisher_handle_;
 
-  std::vector<std::shared_ptr<rclcpp::QOSEventHandlerBase>> event_handlers_;
+  std::unordered_map<rcl_publisher_event_type_t,
+    std::shared_ptr<rclcpp::QOSEventHandlerBase>> event_handlers_;
 
   using IntraProcessManagerWeakPtr =
     std::weak_ptr<rclcpp::experimental::IntraProcessManager>;
@@ -224,6 +346,8 @@ protected:
   uint64_t intra_process_publisher_id_;
 
   rmw_gid_t rmw_gid_;
+
+  const rosidl_message_type_support_t type_support_;
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/publisher_options.hpp

@@ -17,6 +17,7 @@
 
 #include <memory>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 #include "rcl/publisher.h"
@@ -26,6 +27,7 @@
 #include "rclcpp/intra_process_setting.hpp"
 #include "rclcpp/qos.hpp"
 #include "rclcpp/qos_event.hpp"
+#include "rclcpp/qos_overriding_options.hpp"
 
 namespace rclcpp
 {
@@ -44,22 +46,33 @@ struct PublisherOptionsBase
   /// Whether or not to use default callbacks when user doesn't supply any in event_callbacks
   bool use_default_callbacks = true;
 
+  /// Require middleware to generate unique network flow endpoints
+  /// Disabled by default
+  rmw_unique_network_flow_endpoints_requirement_t require_unique_network_flow_endpoints =
+    RMW_UNIQUE_NETWORK_FLOW_ENDPOINTS_NOT_REQUIRED;
+
   /// Callback group in which the waitable items from the publisher should be placed.
   std::shared_ptr<rclcpp::CallbackGroup> callback_group;
 
   /// Optional RMW implementation specific payload to be used during creation of the publisher.
   std::shared_ptr<rclcpp::detail::RMWImplementationSpecificPublisherPayload>
   rmw_implementation_payload = nullptr;
+
+  QosOverridingOptions qos_overriding_options;
 };
 
 /// Structure containing optional configuration for Publishers.
 template<typename Allocator>
 struct PublisherOptionsWithAllocator : public PublisherOptionsBase
 {
+  static_assert(
+    std::is_void_v<typename std::allocator_traits<Allocator>::value_type>,
+    "Publisher allocator value type must be void");
+
   /// Optional custom allocator.
   std::shared_ptr<Allocator> allocator = nullptr;
 
-  PublisherOptionsWithAllocator<Allocator>() {}
+  PublisherOptionsWithAllocator() {}
 
   /// Constructor using base class as input.
   explicit PublisherOptionsWithAllocator(const PublisherOptionsBase & publisher_options_base)
@@ -71,12 +84,11 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
   rcl_publisher_options_t
   to_rcl_publisher_options(const rclcpp::QoS & qos) const
   {
-    rcl_publisher_options_t result;
-    using AllocatorTraits = std::allocator_traits<Allocator>;
-    using MessageAllocatorT = typename AllocatorTraits::template rebind_alloc<MessageT>;
-    auto message_alloc = std::make_shared<MessageAllocatorT>(*this->get_allocator().get());
-    result.allocator = rclcpp::allocator::get_rcl_allocator<MessageT>(*message_alloc);
+    rcl_publisher_options_t result = rcl_publisher_get_default_options();
+    result.allocator = this->get_rcl_allocator();
     result.qos = qos.get_rmw_qos_profile();
+    result.rmw_publisher_options.require_unique_network_flow_endpoints =
+      this->require_unique_network_flow_endpoints;
 
     // Apply payload to rcl_publisher_options if necessary.
     if (rmw_implementation_payload && rmw_implementation_payload->has_been_customized()) {
@@ -92,15 +104,35 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
   get_allocator() const
   {
     if (!this->allocator) {
-      // TODO(wjwwood): I would like to use the commented line instead, but
-      //   cppcheck 1.89 fails with:
-      //     Syntax Error: AST broken, binary operator '>' doesn't have two operands.
-      // return std::make_shared<Allocator>();
-      std::shared_ptr<Allocator> tmp(new Allocator());
-      return tmp;
+      if (!allocator_storage_) {
+        allocator_storage_ = std::make_shared<Allocator>();
+      }
+      return allocator_storage_;
     }
     return this->allocator;
   }
+
+private:
+  using PlainAllocator =
+    typename std::allocator_traits<Allocator>::template rebind_alloc<char>;
+
+  rcl_allocator_t
+  get_rcl_allocator() const
+  {
+    if (!plain_allocator_storage_) {
+      plain_allocator_storage_ =
+        std::make_shared<PlainAllocator>(*this->get_allocator());
+    }
+    return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);
+  }
+
+  // This is a temporal workaround, to make sure that get_allocator()
+  // always returns a copy of the same allocator.
+  mutable std::shared_ptr<Allocator> allocator_storage_;
+
+  // This is a temporal workaround, to keep the plain allocator that backs
+  // up the rcl allocator returned in rcl_publisher_options_t alive.
+  mutable std::shared_ptr<PlainAllocator> plain_allocator_storage_;
 };
 
 using PublisherOptions = PublisherOptionsWithAllocator<std::allocator<void>>;

rclcpp/include/rclcpp/qos.hpp

@@ -18,7 +18,9 @@
 #include <string>
 
 #include "rclcpp/duration.hpp"
+#include "rclcpp/exceptions.hpp"
 #include "rclcpp/visibility_control.hpp"
+#include "rcl/logging_rosout.h"
 #include "rmw/incompatible_qos_events_statuses.h"
 #include "rmw/qos_profiles.h"
 #include "rmw/types.h"
@@ -26,8 +28,48 @@
 namespace rclcpp
 {
 
+RCLCPP_PUBLIC
 std::string qos_policy_name_from_kind(rmw_qos_policy_kind_t policy_kind);
 
+enum class HistoryPolicy
+{
+  KeepLast = RMW_QOS_POLICY_HISTORY_KEEP_LAST,
+  KeepAll = RMW_QOS_POLICY_HISTORY_KEEP_ALL,
+  SystemDefault = RMW_QOS_POLICY_HISTORY_SYSTEM_DEFAULT,
+  Unknown = RMW_QOS_POLICY_HISTORY_UNKNOWN,
+};
+
+enum class ReliabilityPolicy
+{
+  BestEffort = RMW_QOS_POLICY_RELIABILITY_BEST_EFFORT,
+  Reliable = RMW_QOS_POLICY_RELIABILITY_RELIABLE,
+  SystemDefault = RMW_QOS_POLICY_RELIABILITY_SYSTEM_DEFAULT,
+  Unknown = RMW_QOS_POLICY_RELIABILITY_UNKNOWN,
+};
+
+enum class DurabilityPolicy
+{
+  Volatile = RMW_QOS_POLICY_DURABILITY_VOLATILE,
+  TransientLocal = RMW_QOS_POLICY_DURABILITY_TRANSIENT_LOCAL,
+  SystemDefault = RMW_QOS_POLICY_DURABILITY_SYSTEM_DEFAULT,
+  Unknown = RMW_QOS_POLICY_DURABILITY_UNKNOWN,
+};
+
+enum class LivelinessPolicy
+{
+  Automatic = RMW_QOS_POLICY_LIVELINESS_AUTOMATIC,
+  ManualByTopic = RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC,
+  SystemDefault = RMW_QOS_POLICY_LIVELINESS_SYSTEM_DEFAULT,
+  Unknown = RMW_QOS_POLICY_LIVELINESS_UNKNOWN,
+};
+
+enum class QoSCompatibility
+{
+  Ok = RMW_QOS_COMPATIBILITY_OK,
+  Warning = RMW_QOS_COMPATIBILITY_WARNING,
+  Error = RMW_QOS_COMPATIBILITY_ERROR,
+};
+
 /// QoS initialization values, cannot be created directly, use KeepAll or KeepLast instead.
 struct RCLCPP_PUBLIC QoSInitialization
 {
@@ -56,10 +98,32 @@ struct RCLCPP_PUBLIC KeepLast : public rclcpp::QoSInitialization
 };
 
 /// Encapsulation of Quality of Service settings.
+/**
+ * Quality of Service settings control the behavior of publishers, subscriptions,
+ * and other entities, and includes things like how data is sent or resent,
+ * how data is buffered on the publishing and subscribing side, and other things.
+ * See:
+ *   <a href="https://docs.ros.org/en/rolling/Concepts/About-Quality-of-Service-Settings.html">
+ *     https://docs.ros.org/en/rolling/Concepts/About-Quality-of-Service-Settings.html
+ *   </a>
+ */
 class RCLCPP_PUBLIC QoS
 {
 public:
-  /// Constructor which allows you to construct a QoS by giving the only required settings.
+  /// Create a QoS by specifying only the history policy and history depth.
+  /**
+   * When using the default initial profile, the defaults will include:
+   *
+   *   - \link rclcpp::ReliabilityPolicy::Reliable ReliabilityPolicy::Reliable\endlink
+   *   - \link rclcpp::DurabilityPolicy::Volatile DurabilityPolicy::Volatile\endlink
+   *
+   * See rmw_qos_profile_default for a full list of default settings.
+   * If some other rmw_qos_profile_t is passed to initial_profile, then the defaults will derive from
+   * that profile instead.
+   *
+   * \param[in] qos_initialization Specifies history policy and history depth.
+   * \param[in] initial_profile The rmw_qos_profile_t instance on which to base the default settings.
+   */
   explicit
   QoS(
     const QoSInitialization & qos_initialization,
@@ -67,7 +131,11 @@ public:
 
   /// Conversion constructor to ease construction in the common case of just specifying depth.
   /**
-   * Convenience constructor, equivalent to QoS(KeepLast(history_depth)).
+   * This is a convenience constructor that calls QoS(KeepLast(history_depth)).
+   *
+   * \param[in] history_depth How many messages can be queued when publishing
+   *   with a Publisher, or how many messages can be queued before being replaced
+   *   by a Subscription.
    */
   // cppcheck-suppress noExplicitConstructor
   QoS(size_t history_depth);  // NOLINT(runtime/explicit): conversion constructor
@@ -80,6 +148,10 @@ public:
   const rmw_qos_profile_t &
   get_rmw_qos_profile() const;
 
+  /// Set the history policy.
+  QoS &
+  history(HistoryPolicy history);
+
   /// Set the history policy.
   QoS &
   history(rmw_qos_history_policy_t history);
@@ -96,6 +168,10 @@ public:
   QoS &
   reliability(rmw_qos_reliability_policy_t reliability);
 
+  /// Set the reliability setting.
+  QoS &
+  reliability(ReliabilityPolicy reliability);
+
   /// Set the reliability setting to reliable.
   QoS &
   reliable();
@@ -108,6 +184,10 @@ public:
   QoS &
   durability(rmw_qos_durability_policy_t durability);
 
+  /// Set the durability setting.
+  QoS &
+  durability(DurabilityPolicy durability);
+
   /// Set the durability setting to volatile.
   /**
     * Note that this cannot be named `volatile` because it is a C++ keyword.
@@ -139,6 +219,10 @@ public:
   QoS &
   liveliness(rmw_qos_liveliness_policy_t liveliness);
 
+  /// Set the liveliness setting.
+  QoS &
+  liveliness(LivelinessPolicy liveliness);
+
   /// Set the liveliness_lease_duration setting.
   QoS &
   liveliness_lease_duration(rmw_time_t liveliness_lease_duration);
@@ -151,6 +235,42 @@ public:
   QoS &
   avoid_ros_namespace_conventions(bool avoid_ros_namespace_conventions);
 
+  /// Get the history qos policy.
+  HistoryPolicy
+  history() const;
+
+  /// Get the history depth.
+  size_t
+  depth() const;
+
+  /// Get the reliability policy.
+  ReliabilityPolicy
+  reliability() const;
+
+  /// Get the durability policy.
+  DurabilityPolicy
+  durability() const;
+
+  /// Get the deadline duration setting.
+  rclcpp::Duration
+  deadline() const;
+
+  /// Get the lifespan duration setting.
+  rclcpp::Duration
+  lifespan() const;
+
+  /// Get the liveliness policy.
+  LivelinessPolicy
+  liveliness() const;
+
+  /// Get the liveliness lease duration setting.
+  rclcpp::Duration
+  liveliness_lease_duration() const;
+
+  /// Get the `avoid ros namespace convention` setting.
+  bool
+  avoid_ros_namespace_conventions() const;
+
 private:
   rmw_qos_profile_t rmw_qos_profile_;
 };
@@ -161,6 +281,93 @@ bool operator==(const QoS & left, const QoS & right);
 RCLCPP_PUBLIC
 bool operator!=(const QoS & left, const QoS & right);
 
+/// Result type for checking QoS compatibility
+/**
+ * \see rclcpp::qos_check_compatible()
+ */
+struct QoSCheckCompatibleResult
+{
+  /// Compatibility result.
+  QoSCompatibility compatibility;
+
+  /// Reason for a (possible) incompatibility.
+  /**
+   * Set if compatiblity is QoSCompatibility::Warning or QoSCompatiblity::Error.
+   * Not set if the QoS profiles are compatible.
+   */
+  std::string reason;
+};
+
+/// Check if two QoS profiles are compatible.
+/**
+ * Two QoS profiles are compatible if a publisher and subcription
+ * using the QoS policies can communicate with each other.
+ *
+ * If any policies have value "system default" or "unknown" then it is possible that
+ * compatiblity cannot be determined.
+ * In this case, the value QoSCompatility::Warning is set as part of
+ * the returned structure.
+ *
+ * Example usage:
+ *
+ * ```cpp
+ * rclcpp::QoSCheckCompatibleResult result = rclcpp::qos_check_compatible(
+ *   publisher_qos, subscription_qos);
+ * if (rclcpp::QoSCompatibility::Error != result.compatibility) {
+ *   // QoS not compatible ...
+ *   // result.reason contains info about the incompatibility
+ * } else if (rclcpp::QoSCompatibility::Warning != result.compatibility) {
+ *   // QoS may not be compatible ...
+ *   // result.reason contains info about the possible incompatibility
+ * }
+ * ```
+ *
+ * \param[in] publisher_qos: The QoS profile for a publisher.
+ * \param[in] subscription_qos: The QoS profile for a subscription.
+ * \return Struct with compatiblity set to QoSCompatibility::Ok if the QoS profiles are
+ *   compatible, or
+ * \return Struct with compatibility set to QoSCompatibility::Warning if there is a chance
+ *   the QoS profiles are not compatible, or
+ * \return Struct with compatibility set to QoSCompatibility::Error if the QoS profiles are
+ *   not compatible.
+ * \throws rclcpp::exceptions::QoSCheckCompatibilityException if an unexpected error occurs.
+ */
+RCLCPP_PUBLIC
+QoSCheckCompatibleResult
+qos_check_compatible(const QoS & publisher_qos, const QoS & subscription_qos);
+
+/**
+ * Clock QoS class
+ *    - History: Keep last,
+ *    - Depth: 1,
+ *    - Reliability: Best effort,
+ *    - Durability: Volatile,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - avoid ros namespace conventions: false
+ */
+class RCLCPP_PUBLIC ClockQoS : public QoS
+{
+public:
+  explicit
+  ClockQoS(
+    const QoSInitialization & qos_initialization = KeepLast(1));
+};
+
+/**
+ * Sensor Data QoS class
+ *    - History: Keep last,
+ *    - Depth: 5,
+ *    - Reliability: Best effort,
+ *    - Durability: Volatile,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - avoid ros namespace conventions: false
+ */
 class RCLCPP_PUBLIC SensorDataQoS : public QoS
 {
 public:
@@ -171,6 +378,18 @@ public:
   ));
 };
 
+/**
+ * Parameters QoS class
+ *    - History: Keep last,
+ *    - Depth: 1000,
+ *    - Reliability: Reliable,
+ *    - Durability: Volatile,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - Avoid ros namespace conventions: false
+ */
 class RCLCPP_PUBLIC ParametersQoS : public QoS
 {
 public:
@@ -181,6 +400,18 @@ public:
   ));
 };
 
+/**
+ * Services QoS class
+ *    - History: Keep last,
+ *    - Depth: 10,
+ *    - Reliability: Reliable,
+ *    - Durability: Volatile,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - Avoid ros namespace conventions: false
+ */
 class RCLCPP_PUBLIC ServicesQoS : public QoS
 {
 public:
@@ -191,6 +422,18 @@ public:
   ));
 };
 
+/**
+ * Parameter events QoS class
+ *    - History: Keep last,
+ *    - Depth: 1000,
+ *    - Reliability: Reliable,
+ *    - Durability: Volatile,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - Avoid ros namespace conventions: false
+ */
 class RCLCPP_PUBLIC ParameterEventsQoS : public QoS
 {
 public:
@@ -201,6 +444,40 @@ public:
   ));
 };
 
+/**
+ * Rosout QoS class
+ *    - History: Keep last,
+ *    - Depth: 1000,
+ *    - Reliability: Reliable,
+ *    - Durability: TRANSIENT_LOCAL,
+ *    - Deadline: Default,
+ *    - Lifespan: {10, 0},
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: default,
+ *    - Avoid ros namespace conventions: false
+ */
+class RCLCPP_PUBLIC RosoutQoS : public QoS
+{
+public:
+  explicit
+  RosoutQoS(
+    const QoSInitialization & rosout_qos_initialization = (
+      QoSInitialization::from_rmw(rcl_qos_profile_rosout_default)
+  ));
+};
+
+/**
+ * System defaults QoS class
+ *    - History: System default,
+ *    - Depth: System default,
+ *    - Reliability: System default,
+ *    - Durability: System default,
+ *    - Deadline: Default,
+ *    - Lifespan: Default,
+ *    - Liveliness: System default,
+ *    - Liveliness lease duration: System default,
+ *    - Avoid ros namespace conventions: false
+ */
 class RCLCPP_PUBLIC SystemDefaultsQoS : public QoS
 {
 public:

rclcpp/include/rclcpp/qos_event.hpp

@@ -16,15 +16,22 @@
 #define RCLCPP__QOS_EVENT_HPP_
 
 #include <functional>
+#include <memory>
+#include <mutex>
+#include <stdexcept>
 #include <string>
 
 #include "rcl/error_handling.h"
+#include "rcl/event_callback.h"
+#include "rmw/impl/cpp/demangle.hpp"
 #include "rmw/incompatible_qos_events_statuses.h"
 
 #include "rcutils/logging_macros.h"
 
+#include "rclcpp/detail/cpp_callback_trampoline.hpp"
 #include "rclcpp/exceptions.hpp"
 #include "rclcpp/function_traits.hpp"
+#include "rclcpp/logging.hpp"
 #include "rclcpp/waitable.hpp"
 
 namespace rclcpp
@@ -34,6 +41,7 @@ using QOSDeadlineRequestedInfo = rmw_requested_deadline_missed_status_t;
 using QOSDeadlineOfferedInfo = rmw_offered_deadline_missed_status_t;
 using QOSLivelinessChangedInfo = rmw_liveliness_changed_status_t;
 using QOSLivelinessLostInfo = rmw_liveliness_lost_status_t;
+using QOSMessageLostInfo = rmw_message_lost_status_t;
 using QOSOfferedIncompatibleQoSInfo = rmw_offered_qos_incompatible_event_status_t;
 using QOSRequestedIncompatibleQoSInfo = rmw_requested_qos_incompatible_event_status_t;
 
@@ -41,6 +49,7 @@ using QOSDeadlineRequestedCallbackType = std::function<void (QOSDeadlineRequeste
 using QOSDeadlineOfferedCallbackType = std::function<void (QOSDeadlineOfferedInfo &)>;
 using QOSLivelinessChangedCallbackType = std::function<void (QOSLivelinessChangedInfo &)>;
 using QOSLivelinessLostCallbackType = std::function<void (QOSLivelinessLostInfo &)>;
+using QOSMessageLostCallbackType = std::function<void (QOSMessageLostInfo &)>;
 using QOSOfferedIncompatibleQoSCallbackType = std::function<void (QOSOfferedIncompatibleQoSInfo &)>;
 using QOSRequestedIncompatibleQoSCallbackType =
   std::function<void (QOSRequestedIncompatibleQoSInfo &)>;
@@ -59,6 +68,7 @@ struct SubscriptionEventCallbacks
   QOSDeadlineRequestedCallbackType deadline_callback;
   QOSLivelinessChangedCallbackType liveliness_callback;
   QOSRequestedIncompatibleQoSCallbackType incompatible_qos_callback;
+  QOSMessageLostCallbackType message_lost_callback;
 };
 
 class UnsupportedEventTypeException : public exceptions::RCLErrorBase, public std::runtime_error
@@ -79,6 +89,11 @@ public:
 class QOSEventHandlerBase : public Waitable
 {
 public:
+  enum class EntityType : std::size_t
+  {
+    Event,
+  };
+
   RCLCPP_PUBLIC
   virtual ~QOSEventHandlerBase();
 
@@ -89,7 +104,7 @@ public:
 
   /// Add the Waitable to a wait set.
   RCLCPP_PUBLIC
-  bool
+  void
   add_to_wait_set(rcl_wait_set_t * wait_set) override;
 
   /// Check if the Waitable is ready.
@@ -97,25 +112,127 @@ public:
   bool
   is_ready(rcl_wait_set_t * wait_set) override;
 
+  /// Set a callback to be called when each new event instance occurs.
+  /**
+   * The callback receives a size_t which is the number of events that occurred
+   * since the last time this callback was called.
+   * Normally this is 1, but can be > 1 if events occurred before any
+   * callback was set.
+   *
+   * The callback also receives an int identifier argument.
+   * This is needed because a Waitable may be composed of several distinct entities,
+   * such as subscriptions, services, etc.
+   * The application should provide a generic callback function that will be then
+   * forwarded by the waitable to all of its entities.
+   * Before forwarding, a different value for the identifier argument will be
+   * bond to the function.
+   * This implies that the provided callback can use the identifier to behave
+   * differently depending on which entity triggered the waitable to become ready.
+   *
+   * Since this callback is called from the middleware, you should aim to make
+   * it fast and not blocking.
+   * If you need to do a lot of work or wait for some other event, you should
+   * spin it off to another thread, otherwise you risk blocking the middleware.
+   *
+   * Calling it again will clear any previously set callback.
+   *
+   * An exception will be thrown if the callback is not callable.
+   *
+   * This function is thread-safe.
+   *
+   * If you want more information available in the callback, like the qos event
+   * or other information, you may use a lambda with captures or std::bind.
+   *
+   * \sa rmw_event_set_callback
+   * \sa rcl_event_set_callback
+   *
+   * \param[in] callback functor to be called when a new event occurs
+   */
+  void
+  set_on_ready_callback(std::function<void(size_t, int)> callback) override
+  {
+    if (!callback) {
+      throw std::invalid_argument(
+              "The callback passed to set_on_ready_callback "
+              "is not callable.");
+    }
+
+    // Note: we bind the int identifier argument to this waitable's entity types
+    auto new_callback =
+      [callback, this](size_t number_of_events) {
+        try {
+          callback(number_of_events, static_cast<int>(EntityType::Event));
+        } catch (const std::exception & exception) {
+          RCLCPP_ERROR_STREAM(
+            // TODO(wjwwood): get this class access to the node logger it is associated with
+            rclcpp::get_logger("rclcpp"),
+            "rclcpp::QOSEventHandlerBase@" << this <<
+              " caught " << rmw::impl::cpp::demangle(exception) <<
+              " exception in user-provided callback for the 'on ready' callback: " <<
+              exception.what());
+        } catch (...) {
+          RCLCPP_ERROR_STREAM(
+            rclcpp::get_logger("rclcpp"),
+            "rclcpp::QOSEventHandlerBase@" << this <<
+              " caught unhandled exception in user-provided callback " <<
+              "for the 'on ready' callback");
+        }
+      };
+
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+
+    // Set it temporarily to the new callback, while we replace the old one.
+    // This two-step setting, prevents a gap where the old std::function has
+    // been replaced but the middleware hasn't been told about the new one yet.
+    set_on_new_event_callback(
+      rclcpp::detail::cpp_callback_trampoline<const void *, size_t>,
+      static_cast<const void *>(&new_callback));
+
+    // Store the std::function to keep it in scope, also overwrites the existing one.
+    on_new_event_callback_ = new_callback;
+
+    // Set it again, now using the permanent storage.
+    set_on_new_event_callback(
+      rclcpp::detail::cpp_callback_trampoline<const void *, size_t>,
+      static_cast<const void *>(&on_new_event_callback_));
+  }
+
+  /// Unset the callback registered for new events, if any.
+  void
+  clear_on_ready_callback() override
+  {
+    std::lock_guard<std::recursive_mutex> lock(callback_mutex_);
+    if (on_new_event_callback_) {
+      set_on_new_event_callback(nullptr, nullptr);
+      on_new_event_callback_ = nullptr;
+    }
+  }
+
 protected:
+  RCLCPP_PUBLIC
+  void
+  set_on_new_event_callback(rcl_event_callback_t callback, const void * user_data);
+
   rcl_event_t event_handle_;
   size_t wait_set_event_index_;
+  std::recursive_mutex callback_mutex_;
+  std::function<void(size_t)> on_new_event_callback_{nullptr};
 };
 
-template<typename EventCallbackT>
+template<typename EventCallbackT, typename ParentHandleT>
 class QOSEventHandler : public QOSEventHandlerBase
 {
 public:
-  template<typename InitFuncT, typename ParentHandleT, typename EventTypeEnum>
+  template<typename InitFuncT, typename EventTypeEnum>
   QOSEventHandler(
     const EventCallbackT & callback,
     InitFuncT init_func,
     ParentHandleT parent_handle,
     EventTypeEnum event_type)
-  : event_callback_(callback)
+  : parent_handle_(parent_handle), event_callback_(callback)
   {
     event_handle_ = rcl_get_zero_initialized_event();
-    rcl_ret_t ret = init_func(&event_handle_, parent_handle, event_type);
+    rcl_ret_t ret = init_func(&event_handle_, parent_handle.get(), event_type);
     if (ret != RCL_RET_OK) {
       if (ret == RCL_RET_UNSUPPORTED) {
         UnsupportedEventTypeException exc(ret, rcl_get_error_state(), "Failed to initialize event");
@@ -127,27 +244,45 @@ public:
     }
   }
 
-  /// Execute any entities of the Waitable that are ready.
-  void
-  execute() override
+  /// Take data so that the callback cannot be scheduled again
+  std::shared_ptr<void>
+  take_data() override
   {
     EventCallbackInfoT callback_info;
-
     rcl_ret_t ret = rcl_take_event(&event_handle_, &callback_info);
     if (ret != RCL_RET_OK) {
       RCUTILS_LOG_ERROR_NAMED(
         "rclcpp",
         "Couldn't take event info: %s", rcl_get_error_string().str);
-      return;
+      return nullptr;
     }
+    return std::static_pointer_cast<void>(std::make_shared<EventCallbackInfoT>(callback_info));
+  }
 
-    event_callback_(callback_info);
+  std::shared_ptr<void>
+  take_data_by_entity_id(size_t id) override
+  {
+    (void)id;
+    return take_data();
+  }
+
+  /// Execute any entities of the Waitable that are ready.
+  void
+  execute(std::shared_ptr<void> & data) override
+  {
+    if (!data) {
+      throw std::runtime_error("'data' is empty");
+    }
+    auto callback_ptr = std::static_pointer_cast<EventCallbackInfoT>(data);
+    event_callback_(*callback_ptr);
+    callback_ptr.reset();
   }
 
 private:
   using EventCallbackInfoT = typename std::remove_reference<typename
       rclcpp::function_traits::function_traits<EventCallbackT>::template argument_type<0>>::type;
 
+  ParentHandleT parent_handle_;
   EventCallbackT event_callback_;
 };
 

rclcpp/include/rclcpp/qos_overriding_options.hpp

@@ -0,0 +1,154 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__QOS_OVERRIDING_OPTIONS_HPP_
+#define RCLCPP__QOS_OVERRIDING_OPTIONS_HPP_
+
+#include <functional>
+#include <initializer_list>
+#include <ostream>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "rclcpp/qos.hpp"
+#include "rclcpp/visibility_control.hpp"
+
+#include "rcl_interfaces/msg/set_parameters_result.hpp"
+#include "rmw/qos_policy_kind.h"
+
+namespace rclcpp
+{
+
+enum class RCLCPP_PUBLIC_TYPE QosPolicyKind
+{
+  AvoidRosNamespaceConventions = RMW_QOS_POLICY_AVOID_ROS_NAMESPACE_CONVENTIONS,
+  Deadline = RMW_QOS_POLICY_DEADLINE,
+  Depth = RMW_QOS_POLICY_DEPTH,
+  Durability = RMW_QOS_POLICY_DURABILITY,
+  History = RMW_QOS_POLICY_HISTORY,
+  Lifespan = RMW_QOS_POLICY_LIFESPAN,
+  Liveliness = RMW_QOS_POLICY_LIVELINESS,
+  LivelinessLeaseDuration = RMW_QOS_POLICY_LIVELINESS_LEASE_DURATION,
+  Reliability = RMW_QOS_POLICY_RELIABILITY,
+  Invalid = RMW_QOS_POLICY_INVALID,
+};
+
+RCLCPP_PUBLIC
+const char *
+qos_policy_kind_to_cstr(const QosPolicyKind & qpk);
+
+RCLCPP_PUBLIC
+std::ostream &
+operator<<(std::ostream & os, const QosPolicyKind & qpk);
+
+using QosCallbackResult = rcl_interfaces::msg::SetParametersResult;
+using QosCallback = std::function<QosCallbackResult(const rclcpp::QoS &)>;
+
+namespace detail
+{
+// forward declare
+template<typename T>
+class QosParameters;
+}
+
+/// Options that are passed in subscription/publisher constructor to specify QoSConfigurability.
+/**
+ * This options struct allows configuring:
+ * - Which policy kinds will have declared parameters.
+ * - An optional callback, that will be called to validate the final qos profile.
+ * - An optional id. In the case that different qos are desired for two publishers/subscriptions in
+ *   the same topic, this id will allow disambiguating them.
+ *
+ * Example parameter file:
+ *
+ * ```yaml
+ * my_node_name:
+ *  ros__parameters:
+ *    qos_overrides:
+ *      /my/topic/name:
+ *        publisher:  # publisher without provided id
+ *          reliability: reliable
+ *          depth: 100
+ *        publisher_my_id:  # publisher with `id="my_id"
+ *          reliability: reliable
+ *          depth: 10
+ * ```
+ */
+class QosOverridingOptions
+{
+public:
+  /// Default constructor, no overrides allowed.
+  RCLCPP_PUBLIC
+  QosOverridingOptions() = default;
+
+  /// Construct passing a list of QoS policies and a verification callback.
+  /**
+   * This constructor is implicit, e.g.:
+   * ```cpp
+   * node->create_publisher(
+   *   "topic_name",
+   *   default_qos_profile,
+   *   {
+   *     {QosPolicyKind::Reliability},
+   *     [] (auto && qos) {return check_qos_validity(qos)},
+   *     "my_id"
+   *   });
+   * ```
+   * \param policy_kinds list of policy kinds that will be reconfigurable.
+   * \param validation_callback callbak that will be called to validate the validity of
+   *   the qos profile set by the user.
+   * \param id id of the entity.
+   */
+  RCLCPP_PUBLIC
+  QosOverridingOptions(
+    std::initializer_list<QosPolicyKind> policy_kinds,
+    QosCallback validation_callback = nullptr,
+    std::string id = {});
+
+  RCLCPP_PUBLIC
+  const std::string &
+  get_id() const;
+
+  RCLCPP_PUBLIC
+  const std::vector<QosPolicyKind> &
+  get_policy_kinds() const;
+
+  RCLCPP_PUBLIC
+  const QosCallback &
+  get_validation_callback() const;
+
+  /// Construct passing a list of QoS policies and a verification callback.
+  /**
+   * Same as `QosOverridingOptions` constructor, but only declares the default policies:
+   *
+   * History, Depth, Reliability.
+   */
+  RCLCPP_PUBLIC
+  static
+  QosOverridingOptions
+  with_default_policies(QosCallback validation_callback = nullptr, std::string id = {});
+
+private:
+  /// \internal Id of the entity requesting to create parameters.
+  std::string id_;
+  /// \internal Policy kinds that are allowed to be reconfigured.
+  std::vector<QosPolicyKind> policy_kinds_;
+  /// \internal Validation callback that will be called to verify the profile.
+  QosCallback validation_callback_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__QOS_OVERRIDING_OPTIONS_HPP_

rclcpp/include/rclcpp/rate.hpp

@@ -31,6 +31,7 @@ class RateBase
 public:
   RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(RateBase)
 
+  virtual ~RateBase() {}
   virtual bool sleep() = 0;
   virtual bool is_steady() const = 0;
   virtual void reset() = 0;

rclcpp/include/rclcpp/rclcpp.hpp

@@ -81,7 +81,7 @@
  *   - rclcpp/executors/multi_threaded_executor.hpp
  * - CallbackGroups (mechanism for enforcing concurrency rules for callbacks):
  *   - rclcpp::Node::create_callback_group()
- *   - rclcpp::callback_group::CallbackGroup
+ *   - rclcpp::CallbackGroup
  *   - rclcpp/callback_group.hpp
  *
  * Additionally, there are some methods for introspecting the ROS graph:
@@ -117,6 +117,15 @@
  * - Allocator related items:
  *   - rclcpp/allocator/allocator_common.hpp
  *   - rclcpp/allocator/allocator_deleter.hpp
+ * - Generic publisher
+ *   - rclcpp::Node::create_generic_publisher()
+ *   - rclcpp::GenericPublisher
+ *   - rclcpp::GenericPublisher::publish()
+ *   - rclcpp/generic_publisher.hpp
+ * - Generic subscription
+ *   - rclcpp::Node::create_generic_subscription()
+ *   - rclcpp::GenericSubscription
+ *   - rclcpp/generic_subscription.hpp
  * - Memory management tools:
  *   - rclcpp/memory_strategies.hpp
  *   - rclcpp/memory_strategy.hpp
@@ -128,11 +137,12 @@
  *   - rclcpp/context.hpp
  *   - rclcpp/contexts/default_context.hpp
  * - Various utilities:
+ *   - rclcpp/duration.hpp
  *   - rclcpp/function_traits.hpp
  *   - rclcpp/macros.hpp
- *   - rclcpp/scope_exit.hpp
  *   - rclcpp/time.hpp
  *   - rclcpp/utilities.hpp
+ *   - rclcpp/typesupport_helpers.hpp
  *   - rclcpp/visibility_control.hpp
  */
 
@@ -146,14 +156,15 @@
 #include "rclcpp/guard_condition.hpp"
 #include "rclcpp/logging.hpp"
 #include "rclcpp/node.hpp"
-#include "rclcpp/parameter.hpp"
 #include "rclcpp/parameter_client.hpp"
+#include "rclcpp/parameter_event_handler.hpp"
+#include "rclcpp/parameter.hpp"
 #include "rclcpp/parameter_service.hpp"
 #include "rclcpp/rate.hpp"
 #include "rclcpp/time.hpp"
 #include "rclcpp/utilities.hpp"
 #include "rclcpp/visibility_control.hpp"
-#include "rclcpp/wait_set.hpp"
 #include "rclcpp/waitable.hpp"
+#include "rclcpp/wait_set.hpp"
 
 #endif  // RCLCPP__RCLCPP_HPP_