9.2.0

Signed-off-by: William Woodall <william@osrfoundation.org>

README.md

@@ -12,6 +12,6 @@ Visit the [rclcpp API documentation](http://docs.ros2.org/latest/api/rclcpp/) fo
 
 ### 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 +2,131 @@
 Changelog for package rclcpp
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+9.2.0 (2021-09-17)
+------------------
+* Added thread safe for_each_callback_group method (`#1741 <https://github.com/ros2/rclcpp/issues/1741>`_)
+* Added a function rclcpp::wait_for_message() convenience function (`#1705 <https://github.com/ros2/rclcpp/issues/1705>`_) (`#1740 <https://github.com/ros2/rclcpp/issues/1740>`_)
+* Fixed a documentation bug (`#1719 <https://github.com/ros2/rclcpp/issues/1719>`_) (`#1720 <https://github.com/ros2/rclcpp/issues/1720>`_)
+* Contributors: Aditya Pande, Karsten Knese, mergify[bot]
+
+9.1.0 (2021-05-20)
+------------------
+* Allow declaring uninitialized statically typed parameters. (`#1673 <https://github.com/ros2/rclcpp/issues/1673>`_) (`#1681 <https://github.com/ros2/rclcpp/issues/1681>`_)
+* [service] Don't use a weak_ptr to avoid leaking. (`#1668 <https://github.com/ros2/rclcpp/issues/1668>`_) (`#1670 <https://github.com/ros2/rclcpp/issues/1670>`_)
+* Contributors: Jacob Perron, Ivan Santiago Paunovic
+
+9.0.3 (2021-05-10)
+------------------
+* Use OnShutdown callback handle instead of OnShutdown callback (`#1639 <https://github.com/ros2/rclcpp/issues/1639>`_) (`#1650 <https://github.com/ros2/rclcpp/issues/1650>`_)
+* use dynamic_pointer_cast to detect allocator mismatch in intra process manager (`#1643 <https://github.com/ros2/rclcpp/issues/1643>`_) (`#1644 <https://github.com/ros2/rclcpp/issues/1644>`_)
+* 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: 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>`_)

rclcpp/CMakeLists.txt

@@ -5,6 +5,7 @@ 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)
@@ -20,9 +21,10 @@ 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")
   # About -Wno-sign-conversion: With Clang, -Wconversion implies -Wsign-conversion. There are a number of
@@ -39,6 +41,8 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/clock.cpp
   src/rclcpp/context.cpp
   src/rclcpp/contexts/default_context.cpp
+  src/rclcpp/detail/mutex_two_priorities.cpp
+  src/rclcpp/detail/resolve_parameter_overrides.cpp
   src/rclcpp/detail/rmw_implementation_specific_payload.cpp
   src/rclcpp/detail/rmw_implementation_specific_publisher_payload.cpp
   src/rclcpp/detail/rmw_implementation_specific_subscription_payload.cpp
@@ -49,12 +53,14 @@ set(${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
@@ -64,8 +70,8 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/memory_strategies.cpp
   src/rclcpp/memory_strategy.cpp
   src/rclcpp/message_info.cpp
+  src/rclcpp/network_flow_endpoint.cpp
   src/rclcpp/node.cpp
-  src/rclcpp/node_options.cpp
   src/rclcpp/node_interfaces/node_base.cpp
   src/rclcpp/node_interfaces/node_clock.cpp
   src/rclcpp/node_interfaces/node_graph.cpp
@@ -76,12 +82,14 @@ set(${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
@@ -96,6 +104,7 @@ 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
@@ -167,8 +176,12 @@ foreach(interface_file ${interface_files})
     include/rclcpp/node_interfaces/get_${interface_name}.hpp)
 endforeach()
 
-add_library(${PROJECT_NAME}
-  ${${PROJECT_NAME}_SRCS})
+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:${CMAKE_CURRENT_BINARY_DIR}/include>"
@@ -176,6 +189,7 @@ target_include_directories(${PROJECT_NAME} PUBLIC
 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_yaml_param_parser"
@@ -206,6 +220,7 @@ ament_export_include_directories(include)
 ament_export_libraries(${PROJECT_NAME})
 ament_export_targets(${PROJECT_NAME})
 
+ament_export_dependencies(ament_index_cpp)
 ament_export_dependencies(libstatistics_collector)
 ament_export_dependencies(rcl)
 ament_export_dependencies(rcpputils)
@@ -232,3 +247,8 @@ install(
   DIRECTORY include/ ${CMAKE_CURRENT_BINARY_DIR}/include/
   DESTINATION include
 )
+
+if(TEST cppcheck)
+  # must set the property after ament_package()
+  set_tests_properties(cppcheck PROPERTIES TIMEOUT 500)
+endif()

rclcpp/QUALITY_DECLARATION.md

@@ -4,13 +4,13 @@ This document is a declaration of software quality for the `rclcpp` package, bas
 
 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://index.ros.org/doc/ros2/Contributing/Developer-Guide/#package-quality-categories) of the ROS2 developer guide.
+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://index.ros.org/doc/ros2/Contributing/Developer-Guide/#versioning).
+`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]
 
@@ -39,11 +39,11 @@ Headers under the folder `detail` are not considered part of the public API and
 
 ## Change Control Process [2]
 
-`rclcpp` follows the recommended guidelines for ROS Core packages in the [ROS 2 Developer Guide](https://index.ros.org/doc/ros2/Contributing/Developer-Guide/#change-control-process).
+`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://index.ros.org/doc/ros2/Contributing/Developer-Guide/#change-control-process) for additional information.
+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]
 
@@ -51,7 +51,7 @@ This package uses DCO as its confirmation of contributor origin policy. More inf
 
 ### Peer Review Policy [2.iii]
 
-All pull requests will be peer-reviewed, check [ROS 2 Developer Guide](https://index.ros.org/doc/ros2/Contributing/Developer-Guide/#change-control-process) for additional information.
+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]
 
@@ -111,7 +111,7 @@ The tests aim to cover both typical usage and corner cases, but are quantified b
 
 ### Coverage [4.iii]
 
-`rclcpp` follows the recommendations for ROS Core packages in the [ROS 2 Developer Guide](https://index.ros.org/doc/ros2/Contributing/Developer-Guide/#code-coverage), and opts to use line coverage instead of branch coverage.
+`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:
 
@@ -121,13 +121,13 @@ This includes:
 
 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://index.ros.org/doc/ros2/Contributing/ROS-2-On-boarding-Guide/#note-on-coverage-runs).
+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://index.ros.org/doc/ros2/Contributing/Developer-Guide/#performance), and opts to do performance analysis on each release rather than each change.
+`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).
 
@@ -139,7 +139,7 @@ Changes that introduce regressions in performance must be adequately justified i
 
 ### 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://index.ros.org/doc/ros2/Contributing/Developer-Guide/#linters-and-static-analysis). Passing implies there are no linter/static errors when testing against CI of supported platforms.
+`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/)

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/any_executable.hpp

@@ -50,12 +50,6 @@ struct AnyExecutable
   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

@@ -107,12 +107,12 @@ public:
       TRACEPOINT(
         rclcpp_callback_register,
         static_cast<const void *>(this),
-        get_symbol(shared_ptr_callback_));
+        tracetools::get_symbol(shared_ptr_callback_));
     } else if (shared_ptr_with_request_header_callback_) {
       TRACEPOINT(
         rclcpp_callback_register,
         static_cast<const void *>(this),
-        get_symbol(shared_ptr_with_request_header_callback_));
+        tracetools::get_symbol(shared_ptr_with_request_header_callback_));
     }
 #endif  // TRACETOOLS_DISABLED
   }

rclcpp/include/rclcpp/any_subscription_callback.hpp

@@ -15,253 +15,394 @@
 #ifndef RCLCPP__ANY_SUBSCRIPTION_CALLBACK_HPP_
 #define RCLCPP__ANY_SUBSCRIPTION_CALLBACK_HPP_
 
-#include <rmw/types.h>
-
 #include <functional>
 #include <memory>
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
+#include <variant>  // NOLINT[build/include_order]
 
-#include "rclcpp/allocator/allocator_common.hpp"
-#include "rclcpp/function_traits.hpp"
-#include "rclcpp/message_info.hpp"
-#include "rclcpp/visibility_control.hpp"
 #include "tracetools/tracetools.h"
 #include "tracetools/utils.hpp"
 
+#include "rclcpp/allocator/allocator_common.hpp"
+#include "rclcpp/detail/subscription_callback_type_helper.hpp"
+#include "rclcpp/function_traits.hpp"
+#include "rclcpp/message_info.hpp"
+
+template<class>
+inline constexpr bool always_false_v = false;
+
 namespace rclcpp
 {
 
-template<typename MessageT, typename Alloc>
-class AnySubscriptionCallback
+namespace detail
 {
-  using MessageAllocTraits = allocator::AllocRebind<MessageT, Alloc>;
+
+template<typename MessageT, typename AllocatorT>
+struct MessageDeleterHelper
+{
+  using MessageAllocTraits = allocator::AllocRebind<MessageT, AllocatorT>;
   using MessageAlloc = typename MessageAllocTraits::allocator_type;
   using MessageDeleter = allocator::Deleter<MessageAlloc, MessageT>;
-  using ConstMessageSharedPtr = std::shared_ptr<const MessageT>;
-  using MessageUniquePtr = std::unique_ptr<MessageT, MessageDeleter>;
+};
 
-  using SharedPtrCallback = std::function<void (const std::shared_ptr<MessageT>)>;
-  using SharedPtrWithInfoCallback =
-    std::function<void (const std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)>;
-  using ConstSharedPtrCallback = std::function<void (const std::shared_ptr<const MessageT>)>;
-  using ConstSharedPtrWithInfoCallback =
-    std::function<void (const std::shared_ptr<const MessageT>, const rclcpp::MessageInfo &)>;
-  using UniquePtrCallback = std::function<void (MessageUniquePtr)>;
+template<typename MessageT, typename AllocatorT>
+struct AnySubscriptionCallbackHelper
+{
+  using MessageDeleter = typename MessageDeleterHelper<MessageT, AllocatorT>::MessageDeleter;
+
+  using ConstRefCallback =
+    std::function<void (const MessageT &)>;
+  using ConstRefWithInfoCallback =
+    std::function<void (const MessageT &, const rclcpp::MessageInfo &)>;
+
+  using UniquePtrCallback =
+    std::function<void (std::unique_ptr<MessageT, MessageDeleter>)>;
   using UniquePtrWithInfoCallback =
-    std::function<void (MessageUniquePtr, const rclcpp::MessageInfo &)>;
+    std::function<void (std::unique_ptr<MessageT, MessageDeleter>, const rclcpp::MessageInfo &)>;
 
-  SharedPtrCallback shared_ptr_callback_;
-  SharedPtrWithInfoCallback shared_ptr_with_info_callback_;
-  ConstSharedPtrCallback const_shared_ptr_callback_;
-  ConstSharedPtrWithInfoCallback const_shared_ptr_with_info_callback_;
-  UniquePtrCallback unique_ptr_callback_;
-  UniquePtrWithInfoCallback unique_ptr_with_info_callback_;
+  using SharedConstPtrCallback =
+    std::function<void (std::shared_ptr<const MessageT>)>;
+  using SharedConstPtrWithInfoCallback =
+    std::function<void (std::shared_ptr<const MessageT>, const rclcpp::MessageInfo &)>;
+
+  using ConstRefSharedConstPtrCallback =
+    std::function<void (const std::shared_ptr<const MessageT> &)>;
+  using ConstRefSharedConstPtrWithInfoCallback =
+    std::function<void (const std::shared_ptr<const MessageT> &, const rclcpp::MessageInfo &)>;
+
+  // Deprecated signatures:
+  using SharedPtrCallback =
+    std::function<void (std::shared_ptr<MessageT>)>;
+  using SharedPtrWithInfoCallback =
+    std::function<void (std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)>;
+
+  using variant_type = std::variant<
+    ConstRefCallback,
+    ConstRefWithInfoCallback,
+    UniquePtrCallback,
+    UniquePtrWithInfoCallback,
+    SharedConstPtrCallback,
+    SharedConstPtrWithInfoCallback,
+    ConstRefSharedConstPtrCallback,
+    ConstRefSharedConstPtrWithInfoCallback,
+    SharedPtrCallback,
+    SharedPtrWithInfoCallback
+  >;
+};
+
+}  // namespace detail
+
+template<
+  typename MessageT,
+  typename AllocatorT = std::allocator<void>
+>
+class AnySubscriptionCallback
+{
+private:
+  using HelperT = typename rclcpp::detail::AnySubscriptionCallbackHelper<MessageT, AllocatorT>;
+  using MessageDeleterHelper = rclcpp::detail::MessageDeleterHelper<MessageT, AllocatorT>;
+
+  using MessageAllocTraits = typename MessageDeleterHelper::MessageAllocTraits;
+  using MessageAlloc = typename MessageDeleterHelper::MessageAlloc;
+  using MessageDeleter = typename MessageDeleterHelper::MessageDeleter;
+
+  // See AnySubscriptionCallbackHelper for the types of these.
+  using ConstRefCallback = typename HelperT::ConstRefCallback;
+  using ConstRefWithInfoCallback = typename HelperT::ConstRefWithInfoCallback;
+
+  using UniquePtrCallback = typename HelperT::UniquePtrCallback;
+  using UniquePtrWithInfoCallback = typename HelperT::UniquePtrWithInfoCallback;
+
+  using SharedConstPtrCallback = typename HelperT::SharedConstPtrCallback;
+  using SharedConstPtrWithInfoCallback = typename HelperT::SharedConstPtrWithInfoCallback;
+
+  using ConstRefSharedConstPtrCallback =
+    typename HelperT::ConstRefSharedConstPtrCallback;
+  using ConstRefSharedConstPtrWithInfoCallback =
+    typename HelperT::ConstRefSharedConstPtrWithInfoCallback;
+
+  using SharedPtrCallback = typename HelperT::SharedPtrCallback;
+  using SharedPtrWithInfoCallback = typename HelperT::SharedPtrWithInfoCallback;
 
 public:
-  explicit AnySubscriptionCallback(std::shared_ptr<Alloc> allocator)
-  : shared_ptr_callback_(nullptr), shared_ptr_with_info_callback_(nullptr),
-    const_shared_ptr_callback_(nullptr), const_shared_ptr_with_info_callback_(nullptr),
-    unique_ptr_callback_(nullptr), unique_ptr_with_info_callback_(nullptr)
+  explicit
+  AnySubscriptionCallback(const AllocatorT & allocator = AllocatorT())  // NOLINT[runtime/explicit]
   {
-    message_allocator_ = std::make_shared<MessageAlloc>(*allocator.get());
-    allocator::set_allocator_for_deleter(&message_deleter_, message_allocator_.get());
+    message_allocator_ = allocator;
+    allocator::set_allocator_for_deleter(&message_deleter_, &message_allocator_);
+  }
+
+  [[deprecated("use AnySubscriptionCallback(const AllocatorT & allocator) instead")]]
+  explicit
+  AnySubscriptionCallback(std::shared_ptr<AllocatorT> allocator)  // NOLINT[runtime/explicit]
+  {
+    if (allocator == nullptr) {
+      throw std::runtime_error("invalid allocator");
+    }
+    message_allocator_ = *allocator;
+    allocator::set_allocator_for_deleter(&message_deleter_, &message_allocator_);
   }
 
   AnySubscriptionCallback(const AnySubscriptionCallback &) = default;
 
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        SharedPtrCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
+  /// Generic function for setting the callback.
+  /**
+   * There are specializations that overload this in order to deprecate some
+   * callback signatures, and also to fix ambiguity between shared_ptr and
+   * unique_ptr callback signatures when using them with lambda functions.
+   */
+  template<typename CallbackT>
+  AnySubscriptionCallback<MessageT, AllocatorT>
+  set(CallbackT callback)
   {
-    shared_ptr_callback_ = callback;
+    // Use the SubscriptionCallbackTypeHelper to determine the actual type of
+    // the CallbackT, in terms of std::function<...>, which does not happen
+    // automatically with lambda functions in cases where the arguments can be
+    // converted to one another, e.g. shared_ptr and unique_ptr.
+    using scbth = detail::SubscriptionCallbackTypeHelper<MessageT, CallbackT>;
+
+    // Determine if the given CallbackT is a deprecated signature or not.
+    constexpr auto is_deprecated =
+      rclcpp::function_traits::same_arguments<
+      typename scbth::callback_type,
+      std::function<void(std::shared_ptr<MessageT>)>
+      >::value
+      ||
+      rclcpp::function_traits::same_arguments<
+      typename scbth::callback_type,
+      std::function<void(std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)>
+      >::value;
+
+    // Use the discovered type to force the type of callback when assigning
+    // into the variant.
+    if constexpr (is_deprecated) {
+      // If deprecated, call sub-routine that is deprecated.
+      set_deprecated(static_cast<typename scbth::callback_type>(callback));
+    } else {
+      // Otherwise just assign it.
+      callback_variant_ = static_cast<typename scbth::callback_type>(callback);
+    }
+
+    // Return copy of self for easier testing, normally will be compiled out.
+    return *this;
   }
 
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        SharedPtrWithInfoCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
+  /// Function for shared_ptr to non-const MessageT, which is deprecated.
+  // TODO(wjwwood): enable this deprecation after Galactic
+  // [[deprecated(
+  //   "use 'void (std::shared_ptr<const MessageT>)' instead"
+  // )]]
+  void
+  set_deprecated(std::function<void(std::shared_ptr<MessageT>)> callback)
+  // set(CallbackT callback)
   {
-    shared_ptr_with_info_callback_ = callback;
+    callback_variant_ = callback;
   }
 
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        ConstSharedPtrCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
+  /// Function for shared_ptr to non-const MessageT with MessageInfo, which is deprecated.
+  // TODO(wjwwood): enable this deprecation after Galactic
+  // [[deprecated(
+  //   "use 'void (std::shared_ptr<const MessageT>, const rclcpp::MessageInfo &)' instead"
+  // )]]
+  void
+  set_deprecated(
+    std::function<void(std::shared_ptr<MessageT>, const rclcpp::MessageInfo &)> callback)
   {
-    const_shared_ptr_callback_ = callback;
+    callback_variant_ = callback;
   }
 
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        ConstSharedPtrWithInfoCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
+  std::unique_ptr<MessageT, MessageDeleter>
+  create_unique_ptr_from_shared_ptr_message(const std::shared_ptr<const MessageT> & message)
   {
-    const_shared_ptr_with_info_callback_ = callback;
+    auto ptr = MessageAllocTraits::allocate(message_allocator_, 1);
+    MessageAllocTraits::construct(message_allocator_, ptr, *message);
+    return std::unique_ptr<MessageT, MessageDeleter>(ptr, message_deleter_);
   }
 
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        UniquePtrCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
-  {
-    unique_ptr_callback_ = callback;
-  }
-
-  template<
-    typename CallbackT,
-    typename std::enable_if<
-      rclcpp::function_traits::same_arguments<
-        CallbackT,
-        UniquePtrWithInfoCallback
-      >::value
-    >::type * = nullptr
-  >
-  void set(CallbackT callback)
-  {
-    unique_ptr_with_info_callback_ = callback;
-  }
-
-  void dispatch(
-    std::shared_ptr<MessageT> message, const rclcpp::MessageInfo & message_info)
+  void
+  dispatch(
+    std::shared_ptr<MessageT> message,
+    const rclcpp::MessageInfo & message_info)
   {
     TRACEPOINT(callback_start, static_cast<const void *>(this), false);
-    if (shared_ptr_callback_) {
-      shared_ptr_callback_(message);
-    } else if (shared_ptr_with_info_callback_) {
-      shared_ptr_with_info_callback_(message, message_info);
-    } else if (const_shared_ptr_callback_) {
-      const_shared_ptr_callback_(message);
-    } else if (const_shared_ptr_with_info_callback_) {
-      const_shared_ptr_with_info_callback_(message, message_info);
-    } else if (unique_ptr_callback_) {
-      auto ptr = MessageAllocTraits::allocate(*message_allocator_.get(), 1);
-      MessageAllocTraits::construct(*message_allocator_.get(), ptr, *message);
-      unique_ptr_callback_(MessageUniquePtr(ptr, message_deleter_));
-    } else if (unique_ptr_with_info_callback_) {
-      auto ptr = MessageAllocTraits::allocate(*message_allocator_.get(), 1);
-      MessageAllocTraits::construct(*message_allocator_.get(), ptr, *message);
-      unique_ptr_with_info_callback_(MessageUniquePtr(ptr, message_deleter_), message_info);
-    } else {
-      throw std::runtime_error("unexpected message without any callback set");
-    }
-    TRACEPOINT(callback_end, static_cast<const void *>(this));
-  }
-
-  void dispatch_intra_process(
-    ConstMessageSharedPtr message, const rclcpp::MessageInfo & message_info)
-  {
-    TRACEPOINT(callback_start, static_cast<const void *>(this), true);
-    if (const_shared_ptr_callback_) {
-      const_shared_ptr_callback_(message);
-    } else if (const_shared_ptr_with_info_callback_) {
-      const_shared_ptr_with_info_callback_(message, message_info);
-    } else {
-      if (
-        unique_ptr_callback_ || unique_ptr_with_info_callback_ ||
-        shared_ptr_callback_ || shared_ptr_with_info_callback_)
-      {
-        throw std::runtime_error(
-                "unexpected dispatch_intra_process const shared "
-                "message call with no const shared_ptr callback");
-      } else {
-        throw std::runtime_error("unexpected message without any callback set");
+    // Check if the variant is "unset", throw if it is.
+    if (callback_variant_.index() == 0) {
+      if (std::get<0>(callback_variant_) == nullptr) {
+        // This can happen if it is default initialized, or if it is assigned nullptr.
+        throw std::runtime_error("dispatch called on an unset AnySubscriptionCallback");
       }
     }
+    // Dispatch.
+    std::visit(
+      [&message, &message_info, this](auto && callback) {
+        using T = std::decay_t<decltype(callback)>;
+
+        if constexpr (std::is_same_v<T, ConstRefCallback>) {
+          callback(*message);
+        } else if constexpr (std::is_same_v<T, ConstRefWithInfoCallback>) {
+          callback(*message, message_info);
+        } else if constexpr (std::is_same_v<T, UniquePtrCallback>) {
+          callback(create_unique_ptr_from_shared_ptr_message(message));
+        } else if constexpr (std::is_same_v<T, UniquePtrWithInfoCallback>) {
+          callback(create_unique_ptr_from_shared_ptr_message(message), message_info);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, SharedConstPtrCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrCallback>||
+          std::is_same_v<T, SharedPtrCallback>)
+        {
+          callback(message);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, SharedConstPtrWithInfoCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrWithInfoCallback>||
+          std::is_same_v<T, SharedPtrWithInfoCallback>)
+        {
+          callback(message, message_info);
+        } else {
+          static_assert(always_false_v<T>, "unhandled callback type");
+        }
+      }, callback_variant_);
     TRACEPOINT(callback_end, static_cast<const void *>(this));
   }
 
-  void dispatch_intra_process(
-    MessageUniquePtr message, const rclcpp::MessageInfo & message_info)
+  void
+  dispatch_intra_process(
+    std::shared_ptr<const MessageT> message,
+    const rclcpp::MessageInfo & message_info)
   {
     TRACEPOINT(callback_start, static_cast<const void *>(this), true);
-    if (shared_ptr_callback_) {
-      typename std::shared_ptr<MessageT> shared_message = std::move(message);
-      shared_ptr_callback_(shared_message);
-    } else if (shared_ptr_with_info_callback_) {
-      typename std::shared_ptr<MessageT> shared_message = std::move(message);
-      shared_ptr_with_info_callback_(shared_message, message_info);
-    } else if (unique_ptr_callback_) {
-      unique_ptr_callback_(std::move(message));
-    } else if (unique_ptr_with_info_callback_) {
-      unique_ptr_with_info_callback_(std::move(message), message_info);
-    } else if (const_shared_ptr_callback_ || const_shared_ptr_with_info_callback_) {
-      throw std::runtime_error(
-              "unexpected dispatch_intra_process unique message call"
-              " with const shared_ptr callback");
-    } else {
-      throw std::runtime_error("unexpected message without any callback set");
+    // Check if the variant is "unset", throw if it is.
+    if (callback_variant_.index() == 0) {
+      if (std::get<0>(callback_variant_) == nullptr) {
+        // This can happen if it is default initialized, or if it is assigned nullptr.
+        throw std::runtime_error("dispatch called on an unset AnySubscriptionCallback");
+      }
     }
+    // Dispatch.
+    std::visit(
+      [&message, &message_info, this](auto && callback) {
+        using T = std::decay_t<decltype(callback)>;
+
+        if constexpr (std::is_same_v<T, ConstRefCallback>) {
+          callback(*message);
+        } else if constexpr (std::is_same_v<T, ConstRefWithInfoCallback>) {
+          callback(*message, message_info);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, UniquePtrCallback>||
+          std::is_same_v<T, SharedPtrCallback>)
+        {
+          callback(create_unique_ptr_from_shared_ptr_message(message));
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, UniquePtrWithInfoCallback>||
+          std::is_same_v<T, SharedPtrWithInfoCallback>)
+        {
+          callback(create_unique_ptr_from_shared_ptr_message(message), message_info);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, SharedConstPtrCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrCallback>)
+        {
+          callback(message);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, SharedConstPtrWithInfoCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrWithInfoCallback>)
+        {
+          callback(message, message_info);
+        } else {
+          static_assert(always_false_v<T>, "unhandled callback type");
+        }
+      }, callback_variant_);
     TRACEPOINT(callback_end, static_cast<const void *>(this));
   }
 
-  bool use_take_shared_method() const
+  void
+  dispatch_intra_process(
+    std::unique_ptr<MessageT, MessageDeleter> message,
+    const rclcpp::MessageInfo & message_info)
   {
-    return const_shared_ptr_callback_ || const_shared_ptr_with_info_callback_;
+    TRACEPOINT(callback_start, static_cast<const void *>(this), true);
+    // Check if the variant is "unset", throw if it is.
+    if (callback_variant_.index() == 0) {
+      if (std::get<0>(callback_variant_) == nullptr) {
+        // This can happen if it is default initialized, or if it is assigned nullptr.
+        throw std::runtime_error("dispatch called on an unset AnySubscriptionCallback");
+      }
+    }
+    // Dispatch.
+    std::visit(
+      [&message, &message_info](auto && callback) {
+        using T = std::decay_t<decltype(callback)>;
+
+        if constexpr (std::is_same_v<T, ConstRefCallback>) {
+          callback(*message);
+        } else if constexpr (std::is_same_v<T, ConstRefWithInfoCallback>) {
+          callback(*message, message_info);
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, UniquePtrCallback>||
+          std::is_same_v<T, SharedConstPtrCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrCallback>||
+          std::is_same_v<T, SharedPtrCallback>)
+        {
+          callback(std::move(message));
+        } else if constexpr (  // NOLINT[readability/braces]
+          std::is_same_v<T, UniquePtrWithInfoCallback>||
+          std::is_same_v<T, SharedConstPtrWithInfoCallback>||
+          std::is_same_v<T, ConstRefSharedConstPtrWithInfoCallback>||
+          std::is_same_v<T, SharedPtrWithInfoCallback>)
+        {
+          callback(std::move(message), message_info);
+        } else {
+          static_assert(always_false_v<T>, "unhandled callback type");
+        }
+      }, callback_variant_);
+    TRACEPOINT(callback_end, static_cast<const void *>(this));
   }
 
-  void register_callback_for_tracing()
+  constexpr
+  bool
+  use_take_shared_method() const
+  {
+    return
+      std::holds_alternative<SharedConstPtrCallback>(callback_variant_) ||
+      std::holds_alternative<SharedConstPtrWithInfoCallback>(callback_variant_) ||
+      std::holds_alternative<ConstRefSharedConstPtrCallback>(callback_variant_) ||
+      std::holds_alternative<ConstRefSharedConstPtrWithInfoCallback>(callback_variant_);
+  }
+
+  void
+  register_callback_for_tracing()
   {
 #ifndef TRACETOOLS_DISABLED
-    if (shared_ptr_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        static_cast<const void *>(this),
-        get_symbol(shared_ptr_callback_));
-    } else if (shared_ptr_with_info_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        static_cast<const void *>(this),
-        get_symbol(shared_ptr_with_info_callback_));
-    } else if (unique_ptr_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        static_cast<const void *>(this),
-        get_symbol(unique_ptr_callback_));
-    } else if (unique_ptr_with_info_callback_) {
-      TRACEPOINT(
-        rclcpp_callback_register,
-        static_cast<const void *>(this),
-        get_symbol(unique_ptr_with_info_callback_));
-    }
+    std::visit(
+      [this](auto && callback) {
+        TRACEPOINT(
+          rclcpp_callback_register,
+          static_cast<const void *>(this),
+          tracetools::get_symbol(callback));
+      }, callback_variant_);
 #endif  // TRACETOOLS_DISABLED
   }
 
+  typename HelperT::variant_type &
+  get_variant()
+  {
+    return callback_variant_;
+  }
+
+  const typename HelperT::variant_type &
+  get_variant() const
+  {
+    return callback_variant_;
+  }
+
 private:
-  std::shared_ptr<MessageAlloc> message_allocator_;
+  // TODO(wjwwood): switch to inheriting from std::variant (i.e. HelperT::variant_type) once
+  // inheriting from std::variant is realistic (maybe C++23?), see:
+  //   http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2162r0.html
+  // For now, compose the variant into this class as a private attribute.
+  typename HelperT::variant_type callback_variant_;
+
+  MessageAlloc message_allocator_;
   MessageDeleter message_deleter_;
 };
 

rclcpp/include/rclcpp/callback_group.hpp

@@ -85,8 +85,8 @@ public:
    * group, or after, is irrelevant; the callback group will be automatically
    * added to the executor in either case.
    *
-   * \param[in] group_type They type of the callback group.
-   * \param[in] automatically_add_to_executor_with_node a boolean which
+   * \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.
    */
@@ -222,13 +222,6 @@ 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/clock.hpp

@@ -136,7 +136,7 @@ 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

@@ -23,6 +23,7 @@
 #include <typeindex>
 #include <typeinfo>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -47,6 +48,17 @@ public:
 /// Forward declare WeakContextsWrapper
 class WeakContextsWrapper;
 
+class OnShutdownCallbackHandle
+{
+  friend class Context;
+
+public:
+  using OnShutdownCallbackType = std::function<void ()>;
+
+private:
+  std::weak_ptr<OnShutdownCallbackType> callback;
+};
+
 /// Context which encapsulates shared state between nodes and other similar entities.
 /**
  * A context also represents the lifecycle between init and shutdown of rclcpp.
@@ -150,7 +162,7 @@ public:
    */
   RCLCPP_PUBLIC
   std::string
-  shutdown_reason();
+  shutdown_reason() const;
 
   /// Shutdown the context, making it uninitialized and therefore invalid for derived entities.
   /**
@@ -177,7 +189,7 @@ public:
   bool
   shutdown(const std::string & reason);
 
-  using OnShutdownCallback = std::function<void ()>;
+  using OnShutdownCallback = OnShutdownCallbackHandle::OnShutdownCallbackType;
 
   /// Add a on_shutdown callback to be called when shutdown is called for this context.
   /**
@@ -203,23 +215,47 @@ 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 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.
+   * 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);
 
   /// 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 internal rcl context.
   RCLCPP_PUBLIC
@@ -286,7 +322,7 @@ 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_;
@@ -299,8 +335,8 @@ private:
   // 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_;
 
   /// Condition variable for timed sleep (see sleep_for).
   std::condition_variable interrupt_condition_variable_;

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_subscription.hpp

@@ -101,7 +101,7 @@ create_subscription(
     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();
+          subscription_topic_stats->publish_message_and_reset_measurements();
         }
       };
 

rclcpp/include/rclcpp/detail/mutex_two_priorities.hpp

@@ -0,0 +1,76 @@
+// 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__MUTEX_TWO_PRIORITIES_HPP_
+#define RCLCPP__DETAIL__MUTEX_TWO_PRIORITIES_HPP_
+
+#include <condition_variable>
+#include <mutex>
+
+namespace rclcpp
+{
+namespace detail
+{
+/// \internal A mutex that has two locking mechanism, one with higher priority than the other.
+/**
+ * After the current mutex owner release the lock, a thread that used the high
+ * priority mechanism will have priority over threads that used the low priority mechanism.
+ */
+class MutexTwoPriorities
+{
+public:
+  class HighPriorityLockable
+  {
+public:
+    explicit HighPriorityLockable(MutexTwoPriorities & parent);
+
+    void lock();
+
+    void unlock();
+
+private:
+    MutexTwoPriorities & parent_;
+  };
+
+  class LowPriorityLockable
+  {
+public:
+    explicit LowPriorityLockable(MutexTwoPriorities & parent);
+
+    void lock();
+
+    void unlock();
+
+private:
+    MutexTwoPriorities & parent_;
+  };
+
+  HighPriorityLockable
+  get_high_priority_lockable();
+
+  LowPriorityLockable
+  get_low_priority_lockable();
+
+private:
+  std::condition_variable hp_cv_;
+  std::condition_variable lp_cv_;
+  std::mutex cv_mutex_;
+  size_t hp_waiting_count_{0u};
+  bool data_taken_{false};
+};
+
+}  // namespace detail
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__MUTEX_TWO_PRIORITIES_HPP_

rclcpp/include/rclcpp/detail/subscription_callback_type_helper.hpp

@@ -0,0 +1,164 @@
+// 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:
+ *
+ *   #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);
+ *   }
+ *
+ * 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/exceptions/exceptions.hpp

@@ -282,6 +282,20 @@ 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.
+   * \param[in] message custom exception message.
+   */
+  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
 {
@@ -289,6 +303,13 @@ class InvalidQosOverridesException : public std::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

@@ -30,6 +30,7 @@
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
 
+#include "rclcpp/context.hpp"
 #include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/guard_condition.hpp"
 #include "rclcpp/executor_options.hpp"
@@ -448,7 +449,7 @@ protected:
   RCLCPP_PUBLIC
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr
   get_node_by_group(
-    WeakCallbackGroupsToNodesMap weak_groups_to_nodes,
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
     rclcpp::CallbackGroup::SharedPtr group);
 
   /// Return true if the node has been added to this executor.
@@ -460,7 +461,7 @@ protected:
   bool
   has_node(
     const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
-    WeakCallbackGroupsToNodesMap weak_groups_to_nodes) const;
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes) const;
 
   RCLCPP_PUBLIC
   rclcpp::CallbackGroup::SharedPtr
@@ -476,7 +477,7 @@ protected:
     rclcpp::CallbackGroup::SharedPtr group_ptr,
     rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
     WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
-    bool notify = true);
+    bool notify = true) RCPPUTILS_TSA_REQUIRES(mutex_);
 
   /// Remove a callback group from the executor.
   /**
@@ -487,7 +488,7 @@ protected:
   remove_callback_group_from_map(
     rclcpp::CallbackGroup::SharedPtr group_ptr,
     WeakCallbackGroupsToNodesMap & weak_groups_to_nodes,
-    bool notify = true);
+    bool notify = true) RCPPUTILS_TSA_REQUIRES(mutex_);
 
   RCLCPP_PUBLIC
   bool
@@ -497,7 +498,7 @@ protected:
   bool
   get_next_ready_executable_from_map(
     AnyExecutable & any_executable,
-    WeakCallbackGroupsToNodesMap weak_groups_to_nodes);
+    const WeakCallbackGroupsToNodesMap & weak_groups_to_nodes);
 
   RCLCPP_PUBLIC
   bool
@@ -518,7 +519,7 @@ protected:
    */
   RCLCPP_PUBLIC
   virtual void
-  add_callback_groups_from_nodes_associated_to_executor();
+  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;
@@ -532,10 +533,11 @@ protected:
   rcl_wait_set_t wait_set_ = rcl_get_zero_initialized_wait_set();
 
   // Mutex to protect the subsequent memory_strategy_.
-  std::mutex memory_strategy_mutex_;
+  mutable std::mutex mutex_;
 
   /// The memory strategy: an interface for handling user-defined memory allocation strategies.
-  memory_strategy::MemoryStrategy::SharedPtr memory_strategy_;
+  memory_strategy::MemoryStrategy::SharedPtr
+  memory_strategy_ RCPPUTILS_TSA_PT_GUARDED_BY(mutex_);
 
   /// The context associated with this executor.
   std::shared_ptr<rclcpp::Context> context_;
@@ -543,7 +545,7 @@ protected:
   RCLCPP_DISABLE_COPY(Executor)
 
   RCLCPP_PUBLIC
-  void
+  virtual void
   spin_once_impl(std::chrono::nanoseconds timeout);
 
   typedef std::map<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
@@ -552,27 +554,29 @@ protected:
     WeakNodesToGuardConditionsMap;
 
   /// maps nodes to guard conditions
-  WeakNodesToGuardConditionsMap weak_nodes_to_guard_conditions_;
+  WeakNodesToGuardConditionsMap
+  weak_nodes_to_guard_conditions_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
 
   /// maps callback groups associated to nodes
-  WeakCallbackGroupsToNodesMap weak_groups_associated_with_executor_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_;
+  WeakCallbackGroupsToNodesMap
+  weak_groups_to_nodes_associated_with_executor_ RCPPUTILS_TSA_GUARDED_BY(mutex_);
 
   /// maps all callback groups to nodes
-  WeakCallbackGroupsToNodesMap weak_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_;
+  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_;
 };
 
-namespace executor
-{
-
-using Executor [[deprecated("use rclcpp::Executor instead")]] = rclcpp::Executor;
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__EXECUTOR_HPP_

rclcpp/include/rclcpp/executor_options.hpp

@@ -38,20 +38,6 @@ struct ExecutorOptions
   size_t max_conditions;
 };
 
-namespace executor
-{
-
-using ExecutorArgs [[deprecated("use rclcpp::ExecutorOptions instead")]] = ExecutorOptions;
-
-[[deprecated("use rclcpp::ExecutorOptions() instead")]]
-inline
-rclcpp::ExecutorOptions
-create_default_executor_arguments()
-{
-  return rclcpp::ExecutorOptions();
-}
-
-}  // namespace executor
 }  // namespace rclcpp
 
 #endif  // RCLCPP__EXECUTOR_OPTIONS_HPP_

rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp

@@ -22,6 +22,7 @@
 #include <thread>
 #include <unordered_map>
 
+#include "rclcpp/detail/mutex_two_priorities.hpp"
 #include "rclcpp/executor.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/memory_strategies.hpp"
@@ -81,7 +82,7 @@ protected:
 private:
   RCLCPP_DISABLE_COPY(MultiThreadedExecutor)
 
-  std::mutex wait_mutex_;
+  detail::MutexTwoPriorities wait_mutex_;
   size_t number_of_threads_;
   bool yield_before_execute_;
   std::chrono::nanoseconds next_exec_timeout_;

rclcpp/include/rclcpp/executors/static_executor_entities_collector.hpp

@@ -68,6 +68,10 @@ public:
     rcl_guard_condition_t * executor_guard_condition);
 
   /// Finalize StaticExecutorEntitiesCollector to clear resources
+  RCLCPP_PUBLIC
+  bool
+  is_init() {return initialized_;}
+
   RCLCPP_PUBLIC
   void
   fini();
@@ -339,6 +343,9 @@ private:
 
   /// 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>
@@ -78,6 +79,42 @@ 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 or no more work 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
@@ -155,113 +192,23 @@ public:
   std::vector<rclcpp::CallbackGroup::WeakPtr>
   get_automatically_added_callback_groups_from_nodes() override;
 
-  /// Spin (blocking) until the future is complete, it times out waiting, or rclcpp is interrupted.
-  /**
-   * \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 FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
-  rclcpp::FutureReturnCode
-  spin_until_future_complete(
-    FutureT & 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_->init(&wait_set_, memory_strategy_, &interrupt_guard_condition_);
-    RCLCPP_SCOPE_EXIT(entities_collector_->fini());
-
-    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;
-  }
-
-  /// Not yet implemented, see https://github.com/ros2/rclcpp/issues/1219 for tracking
-  RCLCPP_PUBLIC
-  void
-  spin_some(std::chrono::nanoseconds max_duration = std::chrono::nanoseconds(0)) override
-  {
-    (void)max_duration;
-    throw rclcpp::exceptions::UnimplementedError(
-            "spin_some is not implemented for StaticSingleThreadedExecutor, use spin or "
-            "spin_until_future_complete");
-  }
-
-  /// Not yet implemented, see https://github.com/ros2/rclcpp/issues/1219 for tracking
-  RCLCPP_PUBLIC
-  void
-  spin_all(std::chrono::nanoseconds) override
-  {
-    throw rclcpp::exceptions::UnimplementedError(
-            "spin_all is not implemented for StaticSingleThreadedExecutor, use spin or "
-            "spin_until_future_complete");
-  }
-
-  /// Not yet implemented, see https://github.com/ros2/rclcpp/issues/1219 for tracking
-  RCLCPP_PUBLIC
-  void
-  spin_once(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1)) override
-  {
-    (void)timeout;
-    throw rclcpp::exceptions::UnimplementedError(
-            "spin_once is not implemented for StaticSingleThreadedExecutor, use spin or "
-            "spin_until_future_complete");
-  }
-
 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.
+   * @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/experimental/intra_process_manager.hpp

@@ -202,7 +202,8 @@ 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>(
+        msg, sub_ids.take_shared_subscriptions);
     } else if (!sub_ids.take_ownership_subscriptions.empty() && // NOLINT
       sub_ids.take_shared_subscriptions.size() <= 1)
     {
@@ -227,7 +228,7 @@ public:
       // for the buffers that do not require ownership
       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>(
         shared_msg, sub_ids.take_shared_subscriptions);
       this->template add_owned_msg_to_buffers<MessageT, Alloc, Deleter>(
         std::move(message), sub_ids.take_ownership_subscriptions, allocator);
@@ -263,7 +264,7 @@ 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>(
           shared_msg, sub_ids.take_shared_subscriptions);
       }
       return shared_msg;
@@ -273,7 +274,7 @@ public:
       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>(
           shared_msg,
           sub_ids.take_shared_subscriptions);
       }
@@ -307,7 +308,7 @@ private:
   {
     SubscriptionInfo() = default;
 
-    rclcpp::experimental::SubscriptionIntraProcessBase::SharedPtr subscription;
+    rclcpp::experimental::SubscriptionIntraProcessBase::WeakPtr subscription;
     rmw_qos_profile_t qos;
     const char * topic_name;
     bool use_take_shared_method;
@@ -350,7 +351,10 @@ private:
   bool
   can_communicate(PublisherInfo pub_info, SubscriptionInfo sub_info) const;
 
-  template<typename MessageT>
+  template<
+    typename MessageT,
+    typename Alloc,
+    typename Deleter>
   void
   add_shared_msg_to_buffers(
     std::shared_ptr<const MessageT> message,
@@ -361,13 +365,23 @@ private:
       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.subscription.lock();
+      if (subscription_base) {
+        auto subscription = std::dynamic_pointer_cast<
+          rclcpp::experimental::SubscriptionIntraProcess<MessageT, Alloc, Deleter>
+          >(subscription_base);
+        if (nullptr == subscription) {
+          throw std::runtime_error(
+                  "failed to dynamic cast SubscriptionIntraProcessBase to "
+                  "SubscriptionIntraProcess<MessageT, Alloc, Deleter>, which "
+                  "can happen when the publisher and subscription use different "
+                  "allocator types, which is not supported");
+        }
 
-      auto subscription = std::static_pointer_cast<
-        rclcpp::experimental::SubscriptionIntraProcess<MessageT>
-        >(subscription_base);
-
-      subscription->provide_intra_process_message(message);
+        subscription->provide_intra_process_message(message);
+      } else {
+        subscriptions_.erase(id);
+      }
     }
   }
 
@@ -389,24 +403,34 @@ private:
       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.subscription.lock();
+      if (subscription_base) {
+        auto subscription = std::dynamic_pointer_cast<
+          rclcpp::experimental::SubscriptionIntraProcess<MessageT, Alloc, Deleter>
+          >(subscription_base);
+        if (nullptr == subscription) {
+          throw std::runtime_error(
+                  "failed to dynamic cast SubscriptionIntraProcessBase to "
+                  "SubscriptionIntraProcess<MessageT, Alloc, Deleter>, which "
+                  "can happen when the publisher and subscription use different "
+                  "allocator types, which is not supported");
+        }
 
-      auto subscription = std::static_pointer_cast<
-        rclcpp::experimental::SubscriptionIntraProcess<MessageT>
-        >(subscription_base);
+        if (std::next(it) == subscription_ids.end()) {
+          // If this is the last subscription, give up ownership
+          subscription->provide_intra_process_message(std::move(message));
+        } 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 (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_message(std::move(copy_message));
+        }
       } 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);
-
-        subscription->provide_intra_process_message(std::move(copy_message));
+        subscriptions_.erase(subscription_it);
       }
     }
   }

rclcpp/include/rclcpp/function_traits.hpp

@@ -162,6 +162,32 @@ 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/generic_publisher.hpp

@@ -0,0 +1,127 @@
+// 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"
+
+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 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>>
+  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);
+
+private:
+  // The type support library should stay loaded, so it is stored in the GenericPublisher
+  std::shared_ptr<rcpputils::SharedLibrary> ts_lib_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__GENERIC_PUBLISHER_HPP_

rclcpp/include/rclcpp/generic_subscription.hpp

@@ -0,0 +1,161 @@
+// 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;
+
+  /// 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/loaned_message.hpp

@@ -183,14 +183,30 @@ 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

@@ -22,6 +22,7 @@
 
 #include "rcl/node.h"
 #include "rcutils/logging.h"
+#include "rcpputils/filesystem_helper.hpp"
 
 /**
  * \def RCLCPP_LOGGING_ENABLED
@@ -75,6 +76,18 @@ 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 \ref 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:

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>
@@ -41,6 +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"
@@ -150,6 +153,17 @@ public:
   const std::vector<rclcpp::CallbackGroup::WeakPtr> &
   get_callback_groups() const;
 
+  /// 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
+  void
+  for_each_callback_group(const node_interfaces::NodeBaseInterface::CallbackGroupFunction & func);
+
   /// Create and return a Publisher.
   /**
    * The rclcpp::QoS has several convenient constructors, including a
@@ -163,7 +177,7 @@ 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);
@@ -266,6 +280,55 @@ 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.
@@ -305,16 +368,59 @@ 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 a parameter
+  [[deprecated(
+    "declare_parameter() with only a name is deprecated and will be deleted in the future.\n" \
+    "If you want to declare a parameter that won't change type without a default value use:\n" \
+    "`node->declare_parameter<ParameterT>(name)`, where e.g. ParameterT=int64_t.\n\n" \
+    "If you want to declare a parameter that can dynamically change type use:\n" \
+    "```\n" \
+    "rcl_interfaces::msg::ParameterDescriptor descriptor;\n" \
+    "descriptor.dynamic_typing = true;\n" \
+    "node->declare_parameter(name, rclcpp::ParameterValue{}, descriptor);\n" \
+    "```"
+  )]]
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(const std::string & name);
+
   /// Declare and initialize a parameter with a type.
   /**
    * See the non-templated declare_parameter() on this class for details.
@@ -345,6 +451,18 @@ 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"
@@ -785,6 +903,9 @@ 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
@@ -874,12 +995,15 @@ public:
   std::map<std::string, std::vector<std::string>>
   get_service_names_and_types() const;
 
-  /// Return the number of publishers that are advertised on a given topic.
+  /// Return a map of existing service names to list of service types for a specific node.
   /**
-   * \param[in] node_name the node_name on which to count the publishers.
-   * \param[in] namespace_ the namespace of the node associated with the name
-   * \return number of publishers that are advertised on a given topic.
-   * \throws std::runtime_error if publishers could not be counted
+   * 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>>

rclcpp/include/rclcpp/node_impl.hpp

@@ -36,10 +36,12 @@
 
 #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_timer.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"
@@ -152,6 +154,43 @@ 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(
@@ -172,6 +211,24 @@ 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{}};
+  return this->declare_parameter(
+    name,
+    value.get_type(),
+    parameter_descriptor,
+    ignore_override
+  ).get<ParameterT>();
+}
+
 template<typename ParameterT>
 std::vector<ParameterT>
 Node::declare_parameters(

rclcpp/include/rclcpp/node_interfaces/node_base.hpp

@@ -16,10 +16,13 @@
 #define RCLCPP__NODE_INTERFACES__NODE_BASE_HPP_
 
 #include <memory>
+#include <mutex>
 #include <string>
+#include <unordered_map>
 #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"
@@ -30,12 +33,34 @@ namespace rclcpp
 namespace node_interfaces
 {
 
+RCLCPP_PUBLIC
+void global_for_each_callback_group(
+  NodeBaseInterface * node_base_interface,
+  const NodeBaseInterface::CallbackGroupFunction & func);
+
+// Class to hold the global map of mutexes
+class map_of_mutexes final
+{
+public:
+  // Methods need to be protected by internal mutex
+  void create_mutex_of_nodebase(const NodeBaseInterface * nodebase);
+  std::shared_ptr<std::mutex>
+  get_mutex_of_nodebase(const NodeBaseInterface * nodebase);
+  void delete_mutex_of_nodebase(const NodeBaseInterface * nodebase);
+
+private:
+  std::unordered_map<const NodeBaseInterface *, std::shared_ptr<std::mutex>> data_;
+  std::mutex internal_mutex_;
+};
+
 /// Implementation of the NodeBase part of the Node API.
 class NodeBase : public NodeBaseInterface
 {
 public:
   RCLCPP_SMART_PTR_ALIASES_ONLY(NodeBase)
 
+  static map_of_mutexes map_object;
+
   RCLCPP_PUBLIC
   NodeBase(
     const std::string & node_name,

rclcpp/include/rclcpp/node_interfaces/node_base_interface.hpp

@@ -38,6 +38,8 @@ class NodeBaseInterface
 public:
   RCLCPP_SMART_PTR_ALIASES_ONLY(NodeBaseInterface)
 
+  using CallbackGroupFunction = std::function<void (rclcpp::CallbackGroup::SharedPtr)>;
+
   RCLCPP_PUBLIC
   virtual
   ~NodeBaseInterface() = default;

rclcpp/include/rclcpp/node_interfaces/node_parameters.hpp

@@ -103,13 +103,42 @@ public:
   virtual
   ~NodeParameters();
 
+// This is overriding a deprecated method, so we need to ignore the deprecation warning here.
+// Users of the method will still get a warning!
+#ifndef _WIN32
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#else
+# pragma warning(push)
+# pragma warning(disable: 4996)
+#endif
+  [[deprecated(RCLCPP_INTERNAL_NODE_PARAMETERS_INTERFACE_DEPRECATE_DECLARE)]]
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(const std::string & name) override;
+#ifndef _WIN32
+# pragma GCC diagnostic pop
+#else
+# pragma warning(pop)
+#endif
+
   RCLCPP_PUBLIC
   const rclcpp::ParameterValue &
   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

rclcpp/include/rclcpp/node_interfaces/node_parameters_interface.hpp

@@ -45,6 +45,17 @@ struct OnSetParametersCallbackHandle
   OnParametersSetCallbackType callback;
 };
 
+#define RCLCPP_INTERNAL_NODE_PARAMETERS_INTERFACE_DEPRECATE_DECLARE \
+  "declare_parameter() with only a name is deprecated and will be deleted in the future.\n" \
+  "If you want to declare a parameter that won't change type without a default value use:\n" \
+  "`node_params->declare_parameter(name, type)`, with e.g. type=rclcpp::PARAMETER_INTEGER.\n\n" \
+  "If you want to declare a parameter that can dynamically change type use:\n" \
+  "```\n" \
+  "rcl_interfaces::msg::ParameterDescriptor descriptor;\n" \
+  "descriptor.dynamic_typing = true;\n" \
+  "node_params->declare_parameter(name, rclcpp::ParameterValue{}, descriptor);\n" \
+  "```"
+
 /// Pure virtual interface class for the NodeParameters part of the Node API.
 class NodeParametersInterface
 {
@@ -55,6 +66,15 @@ public:
   virtual
   ~NodeParametersInterface() = default;
 
+  /// Declare a parameter.
+  /**
+   * \sa rclcpp::Node::declare_parameter
+   */
+  [[deprecated(RCLCPP_INTERNAL_NODE_PARAMETERS_INTERFACE_DEPRECATE_DECLARE)]]
+  virtual
+  const rclcpp::ParameterValue &
+  declare_parameter(const std::string & name) = 0;
+
   /// Declare and initialize a parameter.
   /**
    * \sa rclcpp::Node::declare_parameter
@@ -64,7 +84,21 @@ 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 +130,7 @@ 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
    */

rclcpp/include/rclcpp/node_interfaces/node_time_source.hpp

@@ -48,7 +48,8 @@ public:
     rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging,
     rclcpp::node_interfaces::NodeClockInterface::SharedPtr node_clock,
     rclcpp::node_interfaces::NodeParametersInterface::SharedPtr node_parameters,
-    const rclcpp::QoS & qos = rclcpp::RosoutQoS()
+    const rclcpp::QoS & qos = rclcpp::RosoutQoS(),
+    bool use_clock_thread = true
   );
 
   RCLCPP_PUBLIC

rclcpp/include/rclcpp/node_options.hpp

@@ -47,6 +47,7 @@ public:
    *   - 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
@@ -258,6 +259,20 @@ 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 &
@@ -384,6 +399,8 @@ private:
 
   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/include/rclcpp/parameter_client.hpp

@@ -31,11 +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"
@@ -154,6 +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 yaml_filename the full name of the yaml file
+   * \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(
@@ -444,6 +483,46 @@ 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(
@@ -524,6 +603,18 @@ protected:
     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(

rclcpp/include/rclcpp/parameter_event_handler.hpp

@@ -0,0 +1,338 @@
+// 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>
+  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);
+
+    event_subscription_ = rclcpp::create_subscription<rcl_interfaces::msg::ParameterEvent>(
+      node_topics, "/parameter_events", qos,
+      std::bind(&ParameterEventHandler::event_callback, this, std::placeholders::_1));
+  }
+
+  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:
+  /// Callback for parameter events subscriptions.
+  RCLCPP_PUBLIC
+  void
+  event_callback(const rcl_interfaces::msg::ParameterEvent & event);
+
+  // 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_;
+
+  // *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*
+
+  // Map container for registered parameters
+  std::unordered_map<
+    std::pair<std::string, std::string>,
+    CallbacksContainerType,
+    StringPairHash
+  > parameter_callbacks_;
+
+  rclcpp::Subscription<rcl_interfaces::msg::ParameterEvent>::SharedPtr event_subscription_;
+
+  std::list<ParameterEventCallbackHandle::WeakPtr> event_callbacks_;
+
+  std::recursive_mutex mutex_;
+};
+
+}  // 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>
@@ -48,6 +49,14 @@ 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/publisher.hpp

@@ -40,6 +40,8 @@
 #include "rclcpp/type_support_decl.hpp"
 #include "rclcpp/visibility_control.hpp"
 
+#include "tracetools/tracetools.h"
+
 namespace rclcpp
 {
 
@@ -261,7 +263,7 @@ 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.
@@ -279,6 +281,10 @@ protected:
   void
   do_inter_process_publish(const MessageT & msg)
   {
+    TRACEPOINT(
+      rclcpp_publish,
+      static_cast<const void *>(publisher_handle_.get()),
+      static_cast<const void *>(&msg));
     auto status = rcl_publish(publisher_handle_.get(), &msg, nullptr);
 
     if (RCL_RET_PUBLISHER_INVALID == status) {
@@ -310,9 +316,9 @@ protected:
   }
 
   void
-  do_loaned_message_publish(MessageT * msg)
+  do_loaned_message_publish(std::unique_ptr<MessageT, std::function<void(MessageT *)>> msg)
   {
-    auto status = rcl_publish_loaned_message(publisher_handle_.get(), 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

rclcpp/include/rclcpp/publisher_base.hpp

@@ -28,6 +28,7 @@
 #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"
@@ -193,6 +194,15 @@ 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;
+
 protected:
   template<typename EventCallbackT>
   void

rclcpp/include/rclcpp/publisher_options.hpp

@@ -45,6 +45,11 @@ 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;
 
@@ -80,6 +85,8 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
     auto message_alloc = std::make_shared<MessageAllocatorT>(*this->get_allocator().get());
     result.allocator = rclcpp::allocator::get_rcl_allocator<MessageT>(*message_alloc);
     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()) {
@@ -95,12 +102,7 @@ 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;
+      return std::make_shared<Allocator>();
     }
     return this->allocator;
   }

rclcpp/include/rclcpp/qos.hpp

@@ -18,6 +18,7 @@
 #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"
@@ -62,6 +63,13 @@ enum class LivelinessPolicy
   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
 {
@@ -95,8 +103,8 @@ struct RCLCPP_PUBLIC KeepLast : public rclcpp::QoSInitialization
  * 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://index.ros.org/doc/ros2/Concepts/About-Quality-of-Service-Settings">
- *     https://index.ros.org/doc/ros2/Concepts/About-Quality-of-Service-Settings
+ *   <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
@@ -273,6 +281,61 @@ 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,

rclcpp/include/rclcpp/rclcpp.hpp

@@ -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
@@ -134,6 +143,7 @@
  *   - rclcpp/scope_exit.hpp
  *   - rclcpp/time.hpp
  *   - rclcpp/utilities.hpp
+ *   - rclcpp/typesupport_helpers.hpp
  *   - rclcpp/visibility_control.hpp
  */
 
@@ -147,14 +157,15 @@
 #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_

rclcpp/include/rclcpp/service.hpp

@@ -177,25 +177,16 @@ public:
     using rosidl_typesupport_cpp::get_service_type_support_handle;
     auto service_type_support_handle = get_service_type_support_handle<ServiceT>();
 
-    std::weak_ptr<rcl_node_t> weak_node_handle(node_handle_);
     // rcl does the static memory allocation here
     service_handle_ = std::shared_ptr<rcl_service_t>(
-      new rcl_service_t, [weak_node_handle](rcl_service_t * service)
+      new rcl_service_t, [handle = node_handle_, service_name](rcl_service_t * service)
       {
-        auto handle = weak_node_handle.lock();
-        if (handle) {
-          if (rcl_service_fini(service, handle.get()) != RCL_RET_OK) {
-            RCLCPP_ERROR(
-              rclcpp::get_node_logger(handle.get()).get_child("rclcpp"),
-              "Error in destruction of rcl service handle: %s",
-              rcl_get_error_string().str);
-            rcl_reset_error();
-          }
-        } else {
+        if (rcl_service_fini(service, handle.get()) != RCL_RET_OK) {
           RCLCPP_ERROR(
-            rclcpp::get_logger("rclcpp"),
-            "Error in destruction of rcl service handle: "
-            "the Node Handle was destructed too early. You will leak memory");
+            rclcpp::get_node_logger(handle.get()).get_child("rclcpp"),
+            "Error in destruction of rcl service handle: %s",
+            rcl_get_error_string().str);
+          rcl_reset_error();
         }
         delete service;
       });
@@ -349,15 +340,6 @@ public:
     send_response(*request_header, *response);
   }
 
-  [[deprecated("use the send_response() which takes references instead of shared pointers")]]
-  void
-  send_response(
-    std::shared_ptr<rmw_request_id_t> req_id,
-    std::shared_ptr<typename ServiceT::Response> response)
-  {
-    send_response(*req_id, *response);
-  }
-
   void
   send_response(rmw_request_id_t & req_id, typename ServiceT::Response & response)
   {

rclcpp/include/rclcpp/subscription.hpp

@@ -171,11 +171,7 @@ public:
 
       // First create a SubscriptionIntraProcess which will be given to the intra-process manager.
       auto context = node_base->get_context();
-      using SubscriptionIntraProcessT = rclcpp::experimental::SubscriptionIntraProcess<
-        CallbackMessageT,
-        AllocatorT,
-        typename MessageUniquePtr::deleter_type>;
-      auto subscription_intra_process = std::make_shared<SubscriptionIntraProcessT>(
+      subscription_intra_process_ = std::make_shared<SubscriptionIntraProcessT>(
         callback,
         options.get_allocator(),
         context,
@@ -185,12 +181,12 @@ public:
       TRACEPOINT(
         rclcpp_subscription_init,
         static_cast<const void *>(get_subscription_handle().get()),
-        static_cast<const void *>(subscription_intra_process.get()));
+        static_cast<const void *>(subscription_intra_process_.get()));
 
       // Add it to the intra process manager.
       using rclcpp::experimental::IntraProcessManager;
       auto ipm = context->get_sub_context<IntraProcessManager>();
-      uint64_t intra_process_subscription_id = ipm->add_subscription(subscription_intra_process);
+      uint64_t intra_process_subscription_id = ipm->add_subscription(subscription_intra_process_);
       this->setup_intra_process(intra_process_subscription_id, ipm);
     }
 
@@ -347,6 +343,11 @@ private:
     message_memory_strategy_;
   /// Component which computes and publishes topic statistics for this subscriber
   SubscriptionTopicStatisticsSharedPtr subscription_topic_statistics_{nullptr};
+  using SubscriptionIntraProcessT = rclcpp::experimental::SubscriptionIntraProcess<
+    CallbackMessageT,
+    AllocatorT,
+    typename MessageUniquePtr::deleter_type>;
+  std::shared_ptr<SubscriptionIntraProcessT> subscription_intra_process_;
 };
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/subscription_base.hpp

@@ -31,6 +31,7 @@
 #include "rclcpp/experimental/subscription_intra_process_base.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/message_info.hpp"
+#include "rclcpp/network_flow_endpoint.hpp"
 #include "rclcpp/qos.hpp"
 #include "rclcpp/qos_event.hpp"
 #include "rclcpp/serialized_message.hpp"
@@ -61,8 +62,11 @@ class SubscriptionBase : public std::enable_shared_from_this<SubscriptionBase>
 public:
   RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(SubscriptionBase)
 
-  /// Default constructor.
+  /// Constructor.
   /**
+   * This accepts rcl_subscription_options_t instead of rclcpp::SubscriptionOptions because
+   * rclcpp::SubscriptionOptions::to_rcl_subscription_options depends on the message type.
+   *
    * \param[in] node_base NodeBaseInterface pointer used in parts of the setup.
    * \param[in] type_support_handle rosidl type support struct, for the Message type of the topic.
    * \param[in] topic_name Name of the topic to subscribe to.
@@ -77,7 +81,7 @@ public:
     const rcl_subscription_options_t & subscription_options,
     bool is_serialized = false);
 
-  /// Default destructor.
+  /// Destructor.
   RCLCPP_PUBLIC
   virtual ~SubscriptionBase();
 
@@ -263,6 +267,15 @@ public:
   bool
   exchange_in_use_by_wait_set_state(void * pointer_to_subscription_part, bool in_use_state);
 
+  /// Get network flow endpoints
+  /**
+   * Describes network flow endpoints that this subscription is receiving messages on
+   * \return vector of NetworkFlowEndpoint
+   */
+  RCLCPP_PUBLIC
+  std::vector<rclcpp::NetworkFlowEndpoint>
+  get_network_flow_endpoints() const;
+
 protected:
   template<typename EventCallbackT>
   void

rclcpp/include/rclcpp/subscription_factory.hpp

@@ -93,7 +93,7 @@ create_subscription_factory(
   auto allocator = options.get_allocator();
 
   using rclcpp::AnySubscriptionCallback;
-  AnySubscriptionCallback<CallbackMessageT, AllocatorT> any_subscription_callback(allocator);
+  AnySubscriptionCallback<CallbackMessageT, AllocatorT> any_subscription_callback(*allocator);
   any_subscription_callback.set(std::forward<CallbackT>(callback));
 
   SubscriptionFactory factory {

rclcpp/include/rclcpp/subscription_options.hpp

@@ -45,6 +45,11 @@ struct SubscriptionOptionsBase
   /// True to ignore local publications.
   bool ignore_local_publications = false;
 
+  /// 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;
+
   /// The callback group for this subscription. NULL to use the default callback group.
   rclcpp::CallbackGroup::SharedPtr callback_group = nullptr;
 
@@ -104,10 +109,12 @@ struct SubscriptionOptionsWithAllocator : public SubscriptionOptionsBase
     rcl_subscription_options_t result = rcl_subscription_get_default_options();
     using AllocatorTraits = std::allocator_traits<Allocator>;
     using MessageAllocatorT = typename AllocatorTraits::template rebind_alloc<MessageT>;
-    auto message_alloc = std::make_shared<MessageAllocatorT>(*allocator.get());
+    auto message_alloc = std::make_shared<MessageAllocatorT>(*this->get_allocator().get());
     result.allocator = allocator::get_rcl_allocator<MessageT>(*message_alloc);
     result.qos = qos.get_rmw_qos_profile();
     result.rmw_subscription_options.ignore_local_publications = this->ignore_local_publications;
+    result.rmw_subscription_options.require_unique_network_flow_endpoints =
+      this->require_unique_network_flow_endpoints;
 
     // Apply payload to rcl_subscription_options if necessary.
     if (rmw_implementation_payload && rmw_implementation_payload->has_been_customized()) {

rclcpp/include/rclcpp/subscription_traits.hpp

@@ -64,7 +64,7 @@ struct is_serialized_callback
 template<typename MessageT>
 struct extract_message_type
 {
-  using type = typename std::remove_cv<MessageT>::type;
+  using type = typename std::remove_cv_t<std::remove_reference_t<MessageT>>;
 };
 
 template<typename MessageT>

rclcpp/include/rclcpp/time_source.hpp

@@ -25,6 +25,7 @@
 #include "rcl_interfaces/msg/parameter_event.hpp"
 
 #include "rclcpp/node.hpp"
+#include "rclcpp/executors.hpp"
 #include "rclcpp/node_interfaces/node_parameters_interface.hpp"
 
 
@@ -32,6 +33,20 @@ namespace rclcpp
 {
 class Clock;
 
+/**
+ * Time source that will drive the attached clocks.
+ *
+ * If the attached node `use_sim_time` parameter is `true`, the attached clocks will
+ * be updated based on messages received.
+ *
+ * The subscription to the clock topic created by the time source can have it's qos reconfigured
+ * using parameter overrides, particularly the following ones are accepted:
+ *
+ * - qos_overrides./clock.depth
+ * - qos_overrides./clock.durability
+ * - qos_overrides./clock.history
+ * - qos_overrides./clock.reliability
+ */
 class TimeSource
 {
 public:
@@ -43,7 +58,10 @@ public:
    * \param qos QoS that will be used when creating a `/clock` subscription.
    */
   RCLCPP_PUBLIC
-  explicit TimeSource(rclcpp::Node::SharedPtr node, const rclcpp::QoS & qos = rclcpp::ClockQoS());
+  explicit TimeSource(
+    rclcpp::Node::SharedPtr node,
+    const rclcpp::QoS & qos = rclcpp::ClockQoS(),
+    bool use_clock_thread = true);
 
   /// Empty constructor
   /**
@@ -52,7 +70,9 @@ public:
    * \param qos QoS that will be used when creating a `/clock` subscription.
    */
   RCLCPP_PUBLIC
-  explicit TimeSource(const rclcpp::QoS & qos = rclcpp::ClockQoS());
+  explicit TimeSource(
+    const rclcpp::QoS & qos = rclcpp::ClockQoS(),
+    bool use_clock_thread = true);
 
   /// Attack node to the time source.
   /**
@@ -104,6 +124,11 @@ public:
   RCLCPP_PUBLIC
   ~TimeSource();
 
+protected:
+  // Dedicated thread for clock subscription.
+  bool use_clock_thread_;
+  std::thread clock_executor_thread_;
+
 private:
   // Preserve the node reference
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_;
@@ -126,9 +151,12 @@ private:
   using SubscriptionT = rclcpp::Subscription<MessageT, Alloc>;
   std::shared_ptr<SubscriptionT> clock_subscription_{nullptr};
   std::mutex clock_sub_lock_;
+  rclcpp::CallbackGroup::SharedPtr clock_callback_group_;
+  rclcpp::executors::SingleThreadedExecutor::SharedPtr clock_executor_;
+  std::promise<void> cancel_clock_executor_promise_;
 
   // The clock callback itself
-  void clock_cb(const rosgraph_msgs::msg::Clock::SharedPtr msg);
+  void clock_cb(std::shared_ptr<const rosgraph_msgs::msg::Clock> msg);
 
   // Create the subscription for the clock topic
   void create_clock_sub();
@@ -142,7 +170,7 @@ private:
   std::shared_ptr<ParamSubscriptionT> parameter_subscription_;
 
   // Callback for parameter updates
-  void on_parameter_event(const rcl_interfaces::msg::ParameterEvent::SharedPtr event);
+  void on_parameter_event(std::shared_ptr<const rcl_interfaces::msg::ParameterEvent> event);
 
   // An enum to hold the parameter state
   enum UseSimTimeParameterState {UNSET, SET_TRUE, SET_FALSE};
@@ -163,7 +191,7 @@ private:
   // This is needed when new clocks are added.
   bool ros_time_active_{false};
   // Last set message to be passed to newly registered clocks
-  rosgraph_msgs::msg::Clock::SharedPtr last_msg_set_;
+  std::shared_ptr<const rosgraph_msgs::msg::Clock> last_msg_set_;
 
   // A lock to protect iterating the associated_clocks_ field.
   std::mutex clock_list_lock_;

rclcpp/include/rclcpp/timer.hpp

@@ -181,7 +181,7 @@ public:
     TRACEPOINT(
       rclcpp_callback_register,
       static_cast<const void *>(&callback_),
-      get_symbol(callback_));
+      tracetools::get_symbol(callback_));
   }
 
   /// Default destructor.

rclcpp/include/rclcpp/topic_statistics/subscription_topic_statistics.hpp

@@ -127,7 +127,7 @@ public:
   /**
    * This method acquires a lock to prevent race conditions to collectors list.
    */
-  virtual void publish_message()
+  virtual void publish_message_and_reset_measurements()
   {
     std::vector<MetricsMessage> msgs;
     rclcpp::Time window_end{get_current_nanoseconds_since_epoch()};
@@ -136,6 +136,7 @@ public:
       std::lock_guard<std::mutex> lock(mutex_);
       for (auto & collector : subscriber_statistics_collectors_) {
         const auto collected_stats = collector->GetStatisticsResults();
+        collector->ClearCurrentMeasurements();
 
         auto message = libstatistics_collector::collector::GenerateStatisticMessage(
           node_name_,

rclcpp/include/rclcpp/typesupport_helpers.hpp

@@ -0,0 +1,57 @@
+// 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__TYPESUPPORT_HELPERS_HPP_
+#define RCLCPP__TYPESUPPORT_HELPERS_HPP_
+
+#include <memory>
+#include <string>
+#include <tuple>
+
+#include "rcpputils/shared_library.hpp"
+#include "rosidl_runtime_cpp/message_type_support_decl.hpp"
+
+#include "rclcpp/visibility_control.hpp"
+
+namespace rclcpp
+{
+/// Load the type support library for the given type.
+/**
+ * \param[in] type The topic type, e.g. "std_msgs/msg/String"
+ * \param[in] typesupport_identifier Type support identifier, typically "rosidl_typesupport_cpp"
+ * \return A shared library
+ */
+RCLCPP_PUBLIC
+std::shared_ptr<rcpputils::SharedLibrary>
+get_typesupport_library(const std::string & type, const std::string & typesupport_identifier);
+
+/// Extract the type support handle from the library.
+/**
+ * The library needs to match the topic type. The shared library must stay loaded for the lifetime of the result.
+ * \param[in] type The topic type, e.g. "std_msgs/msg/String"
+ * \param[in] typesupport_identifier Type support identifier, typically "rosidl_typesupport_cpp"
+ * \param[in] library The shared type support library
+ * \return A type support handle
+ */
+RCLCPP_PUBLIC
+const rosidl_message_type_support_t *
+get_typesupport_handle(
+  const std::string & type,
+  const std::string & typesupport_identifier,
+  rcpputils::SharedLibrary & library);
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__TYPESUPPORT_HELPERS_HPP_

rclcpp/include/rclcpp/utilities.hpp

@@ -143,21 +143,6 @@ RCLCPP_PUBLIC
 bool
 ok(rclcpp::Context::SharedPtr context = nullptr);
 
-/// Return true if init() has already been called for the given context.
-/**
- * If nullptr is given for the context, then the global context is used, i.e.
- * the context initialized by rclcpp::init().
- *
- * Deprecated, as it is no longer different from rcl_ok().
- *
- * \param[in] context Optional check for initialization of this Context.
- * \return true if the context is initialized, and false otherwise
- */
-[[deprecated("use the function ok() instead, which has the same usage.")]]
-RCLCPP_PUBLIC
-bool
-is_initialized(rclcpp::Context::SharedPtr context = nullptr);
-
 /// Shutdown rclcpp context, invalidating it for derived entities.
 /**
  * If nullptr is given for the context, then the global context is used, i.e.

rclcpp/include/rclcpp/wait_for_message.hpp

@@ -0,0 +1,100 @@
+// 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__WAIT_FOR_MESSAGE_HPP_
+#define RCLCPP__WAIT_FOR_MESSAGE_HPP_
+
+#include <memory>
+#include <string>
+
+#include "rclcpp/node.hpp"
+#include "rclcpp/visibility_control.hpp"
+#include "rclcpp/wait_set.hpp"
+
+namespace rclcpp
+{
+/// Wait for the next incoming message.
+/**
+ * Given an already initialized subscription,
+ * wait for the next incoming message to arrive before the specified timeout.
+ *
+ * \param[out] out is the message to be filled when a new message is arriving.
+ * \param[in] subscription shared pointer to a previously initialized subscription.
+ * \param[in] context shared pointer to a context to watch for SIGINT requests.
+ * \param[in] time_to_wait parameter specifying the timeout before returning.
+ * \return true if a message was successfully received, false if message could not
+ * be obtained or shutdown was triggered asynchronously on the context.
+ */
+template<class MsgT, class Rep = int64_t, class Period = std::milli>
+bool wait_for_message(
+  MsgT & out,
+  std::shared_ptr<rclcpp::Subscription<MsgT>> subscription,
+  std::shared_ptr<rclcpp::Context> context,
+  std::chrono::duration<Rep, Period> time_to_wait = std::chrono::duration<Rep, Period>(-1))
+{
+  auto gc = std::make_shared<rclcpp::GuardCondition>(context);
+  auto shutdown_callback_handle = context->add_on_shutdown_callback(
+    [weak_gc = std::weak_ptr<rclcpp::GuardCondition>{gc}]() {
+      auto strong_gc = weak_gc.lock();
+      if (strong_gc) {
+        strong_gc->trigger();
+      }
+    });
+
+  rclcpp::WaitSet wait_set;
+  wait_set.add_subscription(subscription);
+  wait_set.add_guard_condition(gc);
+  auto ret = wait_set.wait(time_to_wait);
+  if (ret.kind() != rclcpp::WaitResultKind::Ready) {
+    return false;
+  }
+
+  if (wait_set.get_rcl_wait_set().guard_conditions[0]) {
+    return false;
+  }
+
+  rclcpp::MessageInfo info;
+  if (!subscription->take(out, info)) {
+    return false;
+  }
+
+  return true;
+}
+
+/// Wait for the next incoming message.
+/**
+ * Wait for the next incoming message to arrive on a specified topic before the specified timeout.
+ *
+ * \param[out] out is the message to be filled when a new message is arriving.
+ * \param[in] node the node pointer to initialize the subscription on.
+ * \param[in] topic the topic to wait for messages.
+ * \param[in] time_to_wait parameter specifying the timeout before returning.
+ * \return true if a message was successfully received, false if message could not
+ * be obtained or shutdown was triggered asynchronously on the context.
+ */
+template<class MsgT, class Rep = int64_t, class Period = std::milli>
+bool wait_for_message(
+  MsgT & out,
+  rclcpp::Node::SharedPtr node,
+  const std::string & topic,
+  std::chrono::duration<Rep, Period> time_to_wait = std::chrono::duration<Rep, Period>(-1))
+{
+  auto sub = node->create_subscription<MsgT>(topic, 1, [](const std::shared_ptr<MsgT>) {});
+  return wait_for_message<MsgT, Rep, Period>(
+    out, sub, node->get_node_options().context(), time_to_wait);
+}
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__WAIT_FOR_MESSAGE_HPP_

rclcpp/package.xml

@@ -2,7 +2,7 @@
 <?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
 <package format="2">
   <name>rclcpp</name>
-  <version>6.2.0</version>
+  <version>9.2.0</version>
   <description>The ROS client library in C++.</description>
   <maintainer email="ivanpauno@ekumenlabs.com">Ivan Paunovic</maintainer>
   <maintainer email="mabel@openrobotics.org">Mabel Zhang</maintainer>
@@ -12,12 +12,14 @@
 
   <buildtool_depend>ament_cmake_ros</buildtool_depend>
 
+  <build_depend>ament_index_cpp</build_depend>
   <build_depend>builtin_interfaces</build_depend>
   <build_depend>rcl_interfaces</build_depend>
   <build_depend>rosgraph_msgs</build_depend>
   <build_depend>rosidl_runtime_cpp</build_depend>
   <build_depend>rosidl_typesupport_c</build_depend>
   <build_depend>rosidl_typesupport_cpp</build_depend>
+  <build_export_depend>ament_index_cpp</build_export_depend>
   <build_export_depend>builtin_interfaces</build_export_depend>
   <build_export_depend>rcl_interfaces</build_export_depend>
   <build_export_depend>rosgraph_msgs</build_export_depend>

rclcpp/src/rclcpp/clock.cpp

@@ -113,7 +113,7 @@ Clock::get_clock_mutex() noexcept
 
 void
 Clock::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/src/rclcpp/context.cpp

@@ -291,7 +291,7 @@ Context::get_domain_id() const
 }
 
 std::string
-Context::shutdown_reason()
+Context::shutdown_reason() const
 {
   std::lock_guard<std::recursive_mutex> lock(init_mutex_);
   return shutdown_reason_;
@@ -315,9 +315,13 @@ Context::shutdown(const std::string & reason)
   // set shutdown reason
   shutdown_reason_ = reason;
   // call each shutdown callback
-  for (const auto & callback : on_shutdown_callbacks_) {
-    callback();
+  {
+    std::lock_guard<std::mutex> lock(on_shutdown_callbacks_mutex_);
+    for (const auto & callback : on_shutdown_callbacks_) {
+      (*callback)();
+    }
   }
+
   // interrupt all blocking sleep_for() and all blocking executors or wait sets
   this->interrupt_all_sleep_for();
   // remove self from the global contexts
@@ -344,20 +348,48 @@ Context::shutdown(const std::string & reason)
 rclcpp::Context::OnShutdownCallback
 Context::on_shutdown(OnShutdownCallback callback)
 {
-  on_shutdown_callbacks_.push_back(callback);
+  add_on_shutdown_callback(callback);
   return callback;
 }
 
-const std::vector<rclcpp::Context::OnShutdownCallback> &
-Context::get_on_shutdown_callbacks() const
+rclcpp::OnShutdownCallbackHandle
+Context::add_on_shutdown_callback(OnShutdownCallback callback)
 {
-  return on_shutdown_callbacks_;
+  auto callback_shared_ptr = std::make_shared<OnShutdownCallback>(callback);
+  {
+    std::lock_guard<std::mutex> lock(on_shutdown_callbacks_mutex_);
+    on_shutdown_callbacks_.emplace(callback_shared_ptr);
+  }
+
+  OnShutdownCallbackHandle callback_handle;
+  callback_handle.callback = callback_shared_ptr;
+  return callback_handle;
 }
 
-std::vector<rclcpp::Context::OnShutdownCallback> &
-Context::get_on_shutdown_callbacks()
+bool
+Context::remove_on_shutdown_callback(const OnShutdownCallbackHandle & callback_handle)
 {
-  return on_shutdown_callbacks_;
+  std::lock_guard<std::mutex> lock(on_shutdown_callbacks_mutex_);
+  auto callback_shared_ptr = callback_handle.callback.lock();
+  if (callback_shared_ptr == nullptr) {
+    return false;
+  }
+  return on_shutdown_callbacks_.erase(callback_shared_ptr) == 1;
+}
+
+std::vector<rclcpp::Context::OnShutdownCallback>
+Context::get_on_shutdown_callbacks() const
+{
+  std::vector<OnShutdownCallback> callbacks;
+
+  {
+    std::lock_guard<std::mutex> lock(on_shutdown_callbacks_mutex_);
+    for (auto & iter : on_shutdown_callbacks_) {
+      callbacks.emplace_back(*iter);
+    }
+  }
+
+  return callbacks;
 }
 
 std::shared_ptr<rcl_context_t>

rclcpp/src/rclcpp/detail/mutex_two_priorities.cpp

@@ -0,0 +1,104 @@
+// 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.
+
+#include "rclcpp/detail/mutex_two_priorities.hpp"
+
+#include <mutex>
+
+namespace rclcpp
+{
+namespace detail
+{
+
+using LowPriorityLockable = MutexTwoPriorities::LowPriorityLockable;
+using HighPriorityLockable = MutexTwoPriorities::HighPriorityLockable;
+
+HighPriorityLockable::HighPriorityLockable(MutexTwoPriorities & parent)
+: parent_(parent)
+{}
+
+void
+HighPriorityLockable::lock()
+{
+  std::unique_lock<std::mutex> guard{parent_.cv_mutex_};
+  if (parent_.data_taken_) {
+    ++parent_.hp_waiting_count_;
+    while (parent_.data_taken_) {
+      parent_.hp_cv_.wait(guard);
+    }
+    --parent_.hp_waiting_count_;
+  }
+  parent_.data_taken_ = true;
+}
+
+void
+HighPriorityLockable::unlock()
+{
+  bool notify_lp{false};
+  {
+    std::lock_guard<std::mutex> guard{parent_.cv_mutex_};
+    parent_.data_taken_ = false;
+    notify_lp = 0u == parent_.hp_waiting_count_;
+  }
+  if (notify_lp) {
+    parent_.lp_cv_.notify_one();
+  } else {
+    parent_.hp_cv_.notify_one();
+  }
+}
+
+LowPriorityLockable::LowPriorityLockable(MutexTwoPriorities & parent)
+: parent_(parent)
+{}
+
+void
+LowPriorityLockable::lock()
+{
+  std::unique_lock<std::mutex> guard{parent_.cv_mutex_};
+  while (parent_.data_taken_ || parent_.hp_waiting_count_) {
+    parent_.lp_cv_.wait(guard);
+  }
+  parent_.data_taken_ = true;
+}
+
+void
+LowPriorityLockable::unlock()
+{
+  bool notify_lp{false};
+  {
+    std::lock_guard<std::mutex> guard{parent_.cv_mutex_};
+    parent_.data_taken_ = false;
+    notify_lp = 0u == parent_.hp_waiting_count_;
+  }
+  if (notify_lp) {
+    parent_.lp_cv_.notify_one();
+  } else {
+    parent_.hp_cv_.notify_one();
+  }
+}
+
+HighPriorityLockable
+MutexTwoPriorities::get_high_priority_lockable()
+{
+  return HighPriorityLockable{*this};
+}
+
+LowPriorityLockable
+MutexTwoPriorities::get_low_priority_lockable()
+{
+  return LowPriorityLockable{*this};
+}
+
+}  // namespace detail
+}  // namespace rclcpp

rclcpp/src/rclcpp/detail/resolve_parameter_overrides.cpp

@@ -0,0 +1,77 @@
+// 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.
+
+#include "./resolve_parameter_overrides.hpp"
+
+#include <string>
+#include <map>
+#include <vector>
+
+#include "rcl_yaml_param_parser/parser.h"
+
+#include "rclcpp/scope_exit.hpp"
+#include "rclcpp/parameter_map.hpp"
+
+std::map<std::string, rclcpp::ParameterValue>
+rclcpp::detail::resolve_parameter_overrides(
+  const std::string & node_fqn,
+  const std::vector<rclcpp::Parameter> & parameter_overrides,
+  const rcl_arguments_t * local_args,
+  const rcl_arguments_t * global_args)
+{
+  std::map<std::string, rclcpp::ParameterValue> result;
+
+  // global before local so that local overwrites global
+  std::array<const rcl_arguments_t *, 2> argument_sources = {global_args, local_args};
+
+  // Get fully qualified node name post-remapping to use to find node's params in yaml files
+
+  for (const rcl_arguments_t * source : argument_sources) {
+    if (!source) {
+      continue;
+    }
+    rcl_params_t * params = NULL;
+    rcl_ret_t ret = rcl_arguments_get_param_overrides(source, &params);
+    if (RCL_RET_OK != ret) {
+      rclcpp::exceptions::throw_from_rcl_error(ret);
+    }
+    if (params) {
+      auto cleanup_params = make_scope_exit(
+        [params]() {
+          rcl_yaml_node_struct_fini(params);
+        });
+      rclcpp::ParameterMap initial_map = rclcpp::parameter_map_from(params);
+
+      // Enforce wildcard matching precedence
+      // TODO(cottsay) implement further wildcard matching
+      const std::array<std::string, 2> node_matching_names{"/**", node_fqn};
+      for (const auto & node_name : node_matching_names) {
+        if (initial_map.count(node_name) > 0) {
+          // Combine parameter yaml files, overwriting values in older ones
+          for (const rclcpp::Parameter & param : initial_map.at(node_name)) {
+            result[param.get_name()] =
+              rclcpp::ParameterValue(param.get_value_message());
+          }
+        }
+      }
+    }
+  }
+
+  // parameter overrides passed to constructor will overwrite overrides from yaml file sources
+  for (auto & param : parameter_overrides) {
+    result[param.get_name()] =
+      rclcpp::ParameterValue(param.get_value_message());
+  }
+  return result;
+}

rclcpp/src/rclcpp/detail/resolve_parameter_overrides.hpp

@@ -0,0 +1,44 @@
+// 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__RESOLVE_PARAMETER_OVERRIDES_HPP_
+#define RCLCPP__DETAIL__RESOLVE_PARAMETER_OVERRIDES_HPP_
+
+#include <string>
+#include <map>
+#include <vector>
+
+#include "rcl/arguments.h"
+
+#include "rclcpp/parameter.hpp"
+#include "rclcpp/parameter_value.hpp"
+#include "rclcpp/visibility_control.hpp"
+
+namespace rclcpp
+{
+namespace detail
+{
+/// \internal Get the parameter overrides from the arguments.
+RCLCPP_LOCAL
+std::map<std::string, rclcpp::ParameterValue>
+resolve_parameter_overrides(
+  const std::string & node_name,
+  const std::vector<rclcpp::Parameter> & parameter_overrides,
+  const rcl_arguments_t * local_args,
+  const rcl_arguments_t * global_args);
+
+}  // namespace detail
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DETAIL__RESOLVE_PARAMETER_OVERRIDES_HPP_

rclcpp/src/rclcpp/duration.cpp

@@ -67,13 +67,27 @@ Duration::operator builtin_interfaces::msg::Duration() const
 {
   builtin_interfaces::msg::Duration msg_duration;
   constexpr rcl_duration_value_t kDivisor = RCL_S_TO_NS(1);
+  constexpr int32_t max_s = std::numeric_limits<int32_t>::max();
+  constexpr int32_t min_s = std::numeric_limits<int32_t>::min();
+  constexpr uint32_t max_ns = std::numeric_limits<uint32_t>::max();
   const auto result = std::div(rcl_duration_.nanoseconds, kDivisor);
   if (result.rem >= 0) {
-    msg_duration.sec = static_cast<std::int32_t>(result.quot);
-    msg_duration.nanosec = static_cast<std::uint32_t>(result.rem);
+    // saturate if we will overflow
+    if (result.quot > max_s) {
+      msg_duration.sec = max_s;
+      msg_duration.nanosec = max_ns;
+    } else {
+      msg_duration.sec = static_cast<int32_t>(result.quot);
+      msg_duration.nanosec = static_cast<uint32_t>(result.rem);
+    }
   } else {
-    msg_duration.sec = static_cast<std::int32_t>(result.quot - 1);
-    msg_duration.nanosec = static_cast<std::uint32_t>(kDivisor + result.rem);
+    if (result.quot <= min_s) {
+      msg_duration.sec = min_s;
+      msg_duration.nanosec = 0u;
+    } else {
+      msg_duration.sec = static_cast<int32_t>(result.quot - 1);
+      msg_duration.nanosec = static_cast<uint32_t>(kDivisor + result.rem);
+    }
   }
   return msg_duration;
 }
@@ -238,11 +252,14 @@ Duration::to_rmw_time() const
     throw std::runtime_error("rmw_time_t cannot be negative");
   }
 
-  // reuse conversion logic from msg creation
-  builtin_interfaces::msg::Duration msg = *this;
+  // Purposefully avoid creating from builtin_interfaces::msg::Duration
+  // to avoid possible overflow converting from int64_t to int32_t, then back to uint64_t
   rmw_time_t result;
-  result.sec = static_cast<uint64_t>(msg.sec);
-  result.nsec = static_cast<uint64_t>(msg.nanosec);
+  constexpr rcl_duration_value_t kDivisor = RCL_S_TO_NS(1);
+  const auto div_result = std::div(rcl_duration_.nanoseconds, kDivisor);
+  result.sec = static_cast<uint64_t>(div_result.quot);
+  result.nsec = static_cast<uint64_t>(div_result.rem);
+
   return result;
 }
 

rclcpp/src/rclcpp/executor.cpp

@@ -30,6 +30,7 @@
 #include "rclcpp/node.hpp"
 #include "rclcpp/scope_exit.hpp"
 #include "rclcpp/utilities.hpp"
+#include "rclcpp/node_interfaces/node_base.hpp"
 
 #include "rcutils/logging_macros.h"
 
@@ -56,7 +57,7 @@ Executor::Executor(const rclcpp::ExecutorOptions & options)
     throw_from_rcl_error(ret, "Failed to create interrupt guard condition in Executor constructor");
   }
 
-  context_->on_shutdown(
+  shutdown_callback_handle_ = context_->add_on_shutdown_callback(
     [weak_gc = std::weak_ptr<rclcpp::GuardCondition>{shutdown_guard_condition_}]() {
       auto strong_gc = weak_gc.lock();
       if (strong_gc) {
@@ -138,12 +139,21 @@ Executor::~Executor()
   }
   // Remove and release the sigint guard condition
   memory_strategy_->remove_guard_condition(&shutdown_guard_condition_->get_rcl_guard_condition());
+
+  // Remove shutdown callback handle registered to Context
+  if (!context_->remove_on_shutdown_callback(shutdown_callback_handle_)) {
+    RCUTILS_LOG_ERROR_NAMED(
+      "rclcpp",
+      "failed to remove registered on_shutdown callback");
+    rcl_reset_error();
+  }
 }
 
 std::vector<rclcpp::CallbackGroup::WeakPtr>
 Executor::get_all_callback_groups()
 {
   std::vector<rclcpp::CallbackGroup::WeakPtr> groups;
+  std::lock_guard<std::mutex> guard{mutex_};
   for (const auto & group_node_ptr : weak_groups_associated_with_executor_to_nodes_) {
     groups.push_back(group_node_ptr.first);
   }
@@ -157,6 +167,7 @@ std::vector<rclcpp::CallbackGroup::WeakPtr>
 Executor::get_manually_added_callback_groups()
 {
   std::vector<rclcpp::CallbackGroup::WeakPtr> groups;
+  std::lock_guard<std::mutex> guard{mutex_};
   for (auto const & group_node_ptr : weak_groups_associated_with_executor_to_nodes_) {
     groups.push_back(group_node_ptr.first);
   }
@@ -167,6 +178,7 @@ std::vector<rclcpp::CallbackGroup::WeakPtr>
 Executor::get_automatically_added_callback_groups_from_nodes()
 {
   std::vector<rclcpp::CallbackGroup::WeakPtr> groups;
+  std::lock_guard<std::mutex> guard{mutex_};
   for (auto const & group_node_ptr : weak_groups_to_nodes_associated_with_executor_) {
     groups.push_back(group_node_ptr.first);
   }
@@ -179,14 +191,13 @@ Executor::add_callback_groups_from_nodes_associated_to_executor()
   for (auto & weak_node : weak_nodes_) {
     auto node = weak_node.lock();
     if (node) {
-      auto group_ptrs = node->get_callback_groups();
-      std::for_each(
-        group_ptrs.begin(), group_ptrs.end(),
-        [this, node](rclcpp::CallbackGroup::WeakPtr group_ptr)
+      rclcpp::node_interfaces::global_for_each_callback_group(
+        node.get(),
+        [this, node](rclcpp::CallbackGroup::SharedPtr shared_group_ptr)
         {
-          auto shared_group_ptr = group_ptr.lock();
-          if (shared_group_ptr && shared_group_ptr->automatically_add_to_executor_with_node() &&
-          !shared_group_ptr->get_associated_with_executor_atomic().load())
+          if (
+            shared_group_ptr->automatically_add_to_executor_with_node() &&
+            !shared_group_ptr->get_associated_with_executor_atomic().load())
           {
             this->add_callback_group_to_map(
               shared_group_ptr,
@@ -233,7 +244,6 @@ Executor::add_callback_group_to_map(
       }
     }
     // Add the node's notify condition to the guard condition handles
-    std::unique_lock<std::mutex> lock(memory_strategy_mutex_);
     memory_strategy_->add_guard_condition(node_ptr->get_notify_guard_condition());
   }
 }
@@ -244,6 +254,7 @@ Executor::add_callback_group(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
   bool notify)
 {
+  std::lock_guard<std::mutex> guard{mutex_};
   this->add_callback_group_to_map(
     group_ptr,
     node_ptr,
@@ -259,18 +270,22 @@ Executor::add_node(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_pt
   if (has_executor.exchange(true)) {
     throw std::runtime_error("Node has already been added to an executor.");
   }
-  for (auto & weak_group : node_ptr->get_callback_groups()) {
-    auto group_ptr = weak_group.lock();
-    if (group_ptr != nullptr && !group_ptr->get_associated_with_executor_atomic().load() &&
-      group_ptr->automatically_add_to_executor_with_node())
+  std::lock_guard<std::mutex> guard{mutex_};
+  rclcpp::node_interfaces::global_for_each_callback_group(
+    node_ptr.get(),
+    [this, node_ptr, notify](rclcpp::CallbackGroup::SharedPtr group_ptr)
     {
-      this->add_callback_group_to_map(
-        group_ptr,
-        node_ptr,
-        weak_groups_to_nodes_associated_with_executor_,
-        notify);
-    }
-  }
+      if (!group_ptr->get_associated_with_executor_atomic().load() &&
+      group_ptr->automatically_add_to_executor_with_node())
+      {
+        this->add_callback_group_to_map(
+          group_ptr,
+          node_ptr,
+          weak_groups_to_nodes_associated_with_executor_,
+          notify);
+      }
+    });
+
   weak_nodes_.push_back(node_ptr);
 }
 
@@ -307,7 +322,6 @@ Executor::remove_callback_group_from_map(
         throw_from_rcl_error(ret, "Failed to trigger guard condition on callback group remove");
       }
     }
-    std::unique_lock<std::mutex> lock(memory_strategy_mutex_);
     memory_strategy_->remove_guard_condition(node_ptr->get_notify_guard_condition());
   }
 }
@@ -317,6 +331,7 @@ Executor::remove_callback_group(
   rclcpp::CallbackGroup::SharedPtr group_ptr,
   bool notify)
 {
+  std::lock_guard<std::mutex> guard{mutex_};
   this->remove_callback_group_from_map(
     group_ptr,
     weak_groups_associated_with_executor_to_nodes_,
@@ -336,6 +351,7 @@ Executor::remove_node(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node
     throw std::runtime_error("Node needs to be associated with an executor.");
   }
 
+  std::lock_guard<std::mutex> guard{mutex_};
   bool found_node = false;
   auto node_it = weak_nodes_.begin();
   while (node_it != weak_nodes_.end()) {
@@ -489,6 +505,7 @@ Executor::set_memory_strategy(rclcpp::memory_strategy::MemoryStrategy::SharedPtr
   if (memory_strategy == nullptr) {
     throw std::runtime_error("Received NULL memory strategy in executor.");
   }
+  std::lock_guard<std::mutex> guard{mutex_};
   memory_strategy_ = memory_strategy;
 }
 
@@ -604,16 +621,18 @@ Executor::execute_subscription(rclcpp::SubscriptionBase::SharedPtr subscription)
         return true;
       },
       [&]() {subscription->handle_loaned_message(loaned_msg, message_info);});
-    rcl_ret_t ret = rcl_return_loaned_message_from_subscription(
-      subscription->get_subscription_handle().get(),
-      loaned_msg);
-    if (RCL_RET_OK != ret) {
-      RCLCPP_ERROR(
-        rclcpp::get_logger("rclcpp"),
-        "rcl_return_loaned_message_from_subscription() failed for subscription on topic '%s': %s",
-        subscription->get_topic_name(), rcl_get_error_string().str);
+    if (nullptr != loaned_msg) {
+      rcl_ret_t ret = rcl_return_loaned_message_from_subscription(
+        subscription->get_subscription_handle().get(),
+        loaned_msg);
+      if (RCL_RET_OK != ret) {
+        RCLCPP_ERROR(
+          rclcpp::get_logger("rclcpp"),
+          "rcl_return_loaned_message_from_subscription() failed for subscription on topic '%s': %s",
+          subscription->get_topic_name(), rcl_get_error_string().str);
+      }
+      loaned_msg = nullptr;
     }
-    loaned_msg = nullptr;
   } else {
     // This case is taking a copy of the message data from the middleware via
     // inter-process communication.
@@ -662,7 +681,7 @@ void
 Executor::wait_for_work(std::chrono::nanoseconds timeout)
 {
   {
-    std::unique_lock<std::mutex> lock(memory_strategy_mutex_);
+    std::lock_guard<std::mutex> guard(mutex_);
 
     // Check weak_nodes_ to find any callback group that is not owned
     // by an executor and add it to the list of callbackgroups for
@@ -741,12 +760,14 @@ Executor::wait_for_work(std::chrono::nanoseconds timeout)
 
   // check the null handles in the wait set and remove them from the handles in memory strategy
   // for callback-based entities
+  std::lock_guard<std::mutex> guard(mutex_);
   memory_strategy_->remove_null_handles(&wait_set_);
 }
 
 rclcpp::node_interfaces::NodeBaseInterface::SharedPtr
 Executor::get_node_by_group(
-  rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap weak_groups_to_nodes,
+  const rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap &
+  weak_groups_to_nodes,
   rclcpp::CallbackGroup::SharedPtr group)
 {
   if (!group) {
@@ -764,6 +785,7 @@ Executor::get_node_by_group(
 rclcpp::CallbackGroup::SharedPtr
 Executor::get_group_by_timer(rclcpp::TimerBase::SharedPtr timer)
 {
+  std::lock_guard<std::mutex> guard{mutex_};
   for (const auto & pair : weak_groups_associated_with_executor_to_nodes_) {
     auto group = pair.first.lock();
     if (!group) {
@@ -804,9 +826,11 @@ Executor::get_next_ready_executable(AnyExecutable & any_executable)
 bool
 Executor::get_next_ready_executable_from_map(
   AnyExecutable & any_executable,
-  rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap weak_groups_to_nodes)
+  const rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap &
+  weak_groups_to_nodes)
 {
   bool success = false;
+  std::lock_guard<std::mutex> guard{mutex_};
   // Check the timers to see if there are any that are ready
   memory_strategy_->get_next_timer(any_executable, weak_groups_to_nodes);
   if (any_executable.timer) {
@@ -893,7 +917,8 @@ Executor::get_next_executable(AnyExecutable & any_executable, std::chrono::nanos
 bool
 Executor::has_node(
   const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
-  rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap weak_groups_to_nodes) const
+  const rclcpp::memory_strategy::MemoryStrategy::WeakCallbackGroupsToNodesMap &
+  weak_groups_to_nodes) const
 {
   return std::find_if(
     weak_groups_to_nodes.begin(),

rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp

@@ -22,6 +22,7 @@
 #include "rclcpp/utilities.hpp"
 #include "rclcpp/scope_exit.hpp"
 
+using rclcpp::detail::MutexTwoPriorities;
 using rclcpp::executors::MultiThreadedExecutor;
 
 MultiThreadedExecutor::MultiThreadedExecutor(
@@ -51,7 +52,8 @@ MultiThreadedExecutor::spin()
   std::vector<std::thread> threads;
   size_t thread_id = 0;
   {
-    std::lock_guard<std::mutex> wait_lock(wait_mutex_);
+    auto low_priority_wait_mutex = wait_mutex_.get_low_priority_lockable();
+    std::lock_guard<MutexTwoPriorities::LowPriorityLockable> wait_lock(low_priority_wait_mutex);
     for (; thread_id < number_of_threads_ - 1; ++thread_id) {
       auto func = std::bind(&MultiThreadedExecutor::run, this, thread_id);
       threads.emplace_back(func);
@@ -76,7 +78,8 @@ MultiThreadedExecutor::run(size_t)
   while (rclcpp::ok(this->context_) && spinning.load()) {
     rclcpp::AnyExecutable any_exec;
     {
-      std::lock_guard<std::mutex> wait_lock(wait_mutex_);
+      auto low_priority_wait_mutex = wait_mutex_.get_low_priority_lockable();
+      std::lock_guard<MutexTwoPriorities::LowPriorityLockable> wait_lock(low_priority_wait_mutex);
       if (!rclcpp::ok(this->context_) || !spinning.load()) {
         return;
       }
@@ -103,7 +106,8 @@ MultiThreadedExecutor::run(size_t)
     execute_any_executable(any_exec);
 
     if (any_exec.timer) {
-      std::lock_guard<std::mutex> wait_lock(wait_mutex_);
+      auto high_priority_wait_mutex = wait_mutex_.get_high_priority_lockable();
+      std::lock_guard<MutexTwoPriorities::HighPriorityLockable> wait_lock(high_priority_wait_mutex);
       auto it = scheduled_timers_.find(any_exec.timer);
       if (it != scheduled_timers_.end()) {
         scheduled_timers_.erase(it);

rclcpp/src/rclcpp/executors/static_executor_entities_collector.cpp

@@ -23,6 +23,7 @@
 
 #include "rclcpp/memory_strategy.hpp"
 #include "rclcpp/executors/static_single_threaded_executor.hpp"
+#include "rclcpp/node_interfaces/node_base.hpp"
 
 using rclcpp::executors::StaticExecutorEntitiesCollector;
 
@@ -76,9 +77,13 @@ StaticExecutorEntitiesCollector::init(
 
   // Add executor's guard condition
   memory_strategy_->add_guard_condition(executor_guard_condition);
+
   // Get memory strategy and executable list. Prepare wait_set_
   std::shared_ptr<void> shared_ptr;
   execute(shared_ptr);
+
+  // The entities collector is now initialized
+  initialized_ = true;
 }
 
 void
@@ -286,18 +291,21 @@ StaticExecutorEntitiesCollector::add_node(
   if (has_executor.exchange(true)) {
     throw std::runtime_error("Node has already been added to an executor.");
   }
-  for (const auto & weak_group : node_ptr->get_callback_groups()) {
-    auto group_ptr = weak_group.lock();
-    if (group_ptr != nullptr && !group_ptr->get_associated_with_executor_atomic().load() &&
-      group_ptr->automatically_add_to_executor_with_node())
+  rclcpp::node_interfaces::global_for_each_callback_group(
+    node_ptr.get(),
+    [this, node_ptr, &is_new_node](rclcpp::CallbackGroup::SharedPtr group_ptr)
     {
-      is_new_node = (add_callback_group(
+      if (
+        !group_ptr->get_associated_with_executor_atomic().load() &&
+        group_ptr->automatically_add_to_executor_with_node())
+      {
+        is_new_node = (add_callback_group(
           group_ptr,
           node_ptr,
           weak_groups_to_nodes_associated_with_executor_) ||
         is_new_node);
-    }
-  }
+      }
+    });
   weak_nodes_.push_back(node_ptr);
   return is_new_node;
 }
@@ -323,8 +331,7 @@ StaticExecutorEntitiesCollector::add_callback_group(
     throw std::runtime_error("Callback group was already added to executor.");
   }
   if (is_new_node) {
-    rclcpp::node_interfaces::NodeBaseInterface::WeakPtr node_weak_ptr(node_ptr);
-    weak_nodes_to_guard_conditions_[node_weak_ptr] = node_ptr->get_notify_guard_condition();
+    weak_nodes_to_guard_conditions_[node_ptr] = node_ptr->get_notify_guard_condition();
     return true;
   }
   return false;
@@ -464,13 +471,11 @@ StaticExecutorEntitiesCollector::add_callback_groups_from_nodes_associated_to_ex
   for (const auto & weak_node : weak_nodes_) {
     auto node = weak_node.lock();
     if (node) {
-      auto group_ptrs = node->get_callback_groups();
-      std::for_each(
-        group_ptrs.begin(), group_ptrs.end(),
-        [this, node](rclcpp::CallbackGroup::WeakPtr group_ptr)
+      rclcpp::node_interfaces::global_for_each_callback_group(
+        node.get(),
+        [this, node](rclcpp::CallbackGroup::SharedPtr shared_group_ptr)
         {
-          auto shared_group_ptr = group_ptr.lock();
-          if (shared_group_ptr && shared_group_ptr->automatically_add_to_executor_with_node() &&
+          if (shared_group_ptr->automatically_add_to_executor_with_node() &&
           !shared_group_ptr->get_associated_with_executor_atomic().load())
           {
             add_callback_group(

rclcpp/src/rclcpp/executors/static_single_threaded_executor.cpp

@@ -14,6 +14,7 @@
 
 #include "rclcpp/executors/static_single_threaded_executor.hpp"
 
+#include <chrono>
 #include <memory>
 #include <vector>
 
@@ -29,7 +30,12 @@ StaticSingleThreadedExecutor::StaticSingleThreadedExecutor(
   entities_collector_ = std::make_shared<StaticExecutorEntitiesCollector>();
 }
 
-StaticSingleThreadedExecutor::~StaticSingleThreadedExecutor() {}
+StaticSingleThreadedExecutor::~StaticSingleThreadedExecutor()
+{
+  if (entities_collector_->is_init()) {
+    entities_collector_->fini();
+  }
+}
 
 void
 StaticSingleThreadedExecutor::spin()
@@ -42,7 +48,6 @@ StaticSingleThreadedExecutor::spin()
   // Set memory_strategy_ and exec_list_ based on weak_nodes_
   // Prepare wait_set_ based on memory_strategy_
   entities_collector_->init(&wait_set_, memory_strategy_, &interrupt_guard_condition_);
-  RCLCPP_SCOPE_EXIT(entities_collector_->fini());
 
   while (rclcpp::ok(this->context_) && spinning.load()) {
     // Refresh wait set and wait for work
@@ -51,6 +56,79 @@ StaticSingleThreadedExecutor::spin()
   }
 }
 
+void
+StaticSingleThreadedExecutor::spin_some(std::chrono::nanoseconds max_duration)
+{
+  // In this context a 0 input max_duration means no duration limit
+  if (std::chrono::nanoseconds(0) == max_duration) {
+    max_duration = std::chrono::nanoseconds::max();
+  }
+
+  return this->spin_some_impl(max_duration, false);
+}
+
+void
+StaticSingleThreadedExecutor::spin_all(std::chrono::nanoseconds max_duration)
+{
+  if (max_duration <= std::chrono::nanoseconds(0)) {
+    throw std::invalid_argument("max_duration must be positive");
+  }
+  return this->spin_some_impl(max_duration, true);
+}
+
+void
+StaticSingleThreadedExecutor::spin_some_impl(std::chrono::nanoseconds max_duration, bool exhaustive)
+{
+  // Make sure the entities collector has been initialized
+  if (!entities_collector_->is_init()) {
+    entities_collector_->init(&wait_set_, memory_strategy_, &interrupt_guard_condition_);
+  }
+
+  auto start = std::chrono::steady_clock::now();
+  auto max_duration_not_elapsed = [max_duration, start]() {
+      if (std::chrono::nanoseconds(0) == max_duration) {
+        // told to spin forever if need be
+        return true;
+      } else if (std::chrono::steady_clock::now() - start < max_duration) {
+        // told to spin only for some maximum amount of time
+        return true;
+      }
+      // spun too long
+      return false;
+    };
+
+  if (spinning.exchange(true)) {
+    throw std::runtime_error("spin_some() called while already spinning");
+  }
+  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
+
+  while (rclcpp::ok(context_) && spinning.load() && max_duration_not_elapsed()) {
+    // Get executables that are ready now
+    entities_collector_->refresh_wait_set(std::chrono::milliseconds::zero());
+    // Execute ready executables
+    bool work_available = execute_ready_executables();
+    if (!work_available || !exhaustive) {
+      break;
+    }
+  }
+}
+
+void
+StaticSingleThreadedExecutor::spin_once_impl(std::chrono::nanoseconds timeout)
+{
+  // Make sure the entities collector has been initialized
+  if (!entities_collector_->is_init()) {
+    entities_collector_->init(&wait_set_, memory_strategy_, &interrupt_guard_condition_);
+  }
+
+  if (rclcpp::ok(context_) && spinning.load()) {
+    // Wait until we have a ready entity or timeout expired
+    entities_collector_->refresh_wait_set(timeout);
+    // Execute ready executables
+    execute_ready_executables(true);
+  }
+}
+
 void
 StaticSingleThreadedExecutor::add_callback_group(
   rclcpp::CallbackGroup::SharedPtr group_ptr,
@@ -138,14 +216,20 @@ StaticSingleThreadedExecutor::remove_node(std::shared_ptr<rclcpp::Node> node_ptr
   this->remove_node(node_ptr->get_node_base_interface(), notify);
 }
 
-void
-StaticSingleThreadedExecutor::execute_ready_executables()
+bool
+StaticSingleThreadedExecutor::execute_ready_executables(bool spin_once)
 {
+  bool any_ready_executable = false;
+
   // Execute all the ready subscriptions
   for (size_t i = 0; i < wait_set_.size_of_subscriptions; ++i) {
     if (i < entities_collector_->get_number_of_subscriptions()) {
       if (wait_set_.subscriptions[i]) {
         execute_subscription(entities_collector_->get_subscription(i));
+        if (spin_once) {
+          return true;
+        }
+        any_ready_executable = true;
       }
     }
   }
@@ -154,6 +238,10 @@ StaticSingleThreadedExecutor::execute_ready_executables()
     if (i < entities_collector_->get_number_of_timers()) {
       if (wait_set_.timers[i] && entities_collector_->get_timer(i)->is_ready()) {
         execute_timer(entities_collector_->get_timer(i));
+        if (spin_once) {
+          return true;
+        }
+        any_ready_executable = true;
       }
     }
   }
@@ -162,6 +250,10 @@ StaticSingleThreadedExecutor::execute_ready_executables()
     if (i < entities_collector_->get_number_of_services()) {
       if (wait_set_.services[i]) {
         execute_service(entities_collector_->get_service(i));
+        if (spin_once) {
+          return true;
+        }
+        any_ready_executable = true;
       }
     }
   }
@@ -170,14 +262,24 @@ StaticSingleThreadedExecutor::execute_ready_executables()
     if (i < entities_collector_->get_number_of_clients()) {
       if (wait_set_.clients[i]) {
         execute_client(entities_collector_->get_client(i));
+        if (spin_once) {
+          return true;
+        }
+        any_ready_executable = true;
       }
     }
   }
   // Execute all the ready waitables
   for (size_t i = 0; i < entities_collector_->get_number_of_waitables(); ++i) {
-    if (entities_collector_->get_waitable(i)->is_ready(&wait_set_)) {
-      std::shared_ptr<void> shared_ptr;
-      entities_collector_->get_waitable(i)->execute(shared_ptr);
+    auto waitable = entities_collector_->get_waitable(i);
+    if (waitable->is_ready(&wait_set_)) {
+      auto data = waitable->take_data();
+      waitable->execute(data);
+      if (spin_once) {
+        return true;
+      }
+      any_ready_executable = true;
     }
   }
+  return any_ready_executable;
 }

rclcpp/src/rclcpp/generic_publisher.cpp

@@ -0,0 +1,34 @@
+// 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.
+
+#include "rclcpp/generic_publisher.hpp"
+
+#include <memory>
+#include <string>
+
+namespace rclcpp
+{
+
+void GenericPublisher::publish(const rclcpp::SerializedMessage & message)
+{
+  auto return_code = rcl_publish_serialized_message(
+    get_publisher_handle().get(), &message.get_rcl_serialized_message(), NULL);
+
+  if (return_code != RCL_RET_OK) {
+    rclcpp::exceptions::throw_from_rcl_error(return_code, "failed to publish serialized message");
+  }
+}
+
+}  // namespace rclcpp

rclcpp/src/rclcpp/generic_subscription.cpp

@@ -0,0 +1,67 @@
+// 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.
+
+#include "rclcpp/generic_subscription.hpp"
+
+#include <memory>
+#include <string>
+
+#include "rcl/subscription.h"
+
+#include "rclcpp/exceptions.hpp"
+
+namespace rclcpp
+{
+
+std::shared_ptr<void> GenericSubscription::create_message()
+{
+  return create_serialized_message();
+}
+
+std::shared_ptr<rclcpp::SerializedMessage> GenericSubscription::create_serialized_message()
+{
+  return std::make_shared<rclcpp::SerializedMessage>(0);
+}
+
+void GenericSubscription::handle_message(
+  std::shared_ptr<void> & message, const rclcpp::MessageInfo & message_info)
+{
+  (void) message_info;
+  auto typed_message = std::static_pointer_cast<rclcpp::SerializedMessage>(message);
+  callback_(typed_message);
+}
+
+void GenericSubscription::handle_loaned_message(
+  void * message, const rclcpp::MessageInfo & message_info)
+{
+  (void) message;
+  (void) message_info;
+  throw rclcpp::exceptions::UnimplementedError(
+          "handle_loaned_message is not implemented for GenericSubscription");
+}
+
+void GenericSubscription::return_message(std::shared_ptr<void> & message)
+{
+  auto typed_message = std::static_pointer_cast<rclcpp::SerializedMessage>(message);
+  return_serialized_message(typed_message);
+}
+
+void GenericSubscription::return_serialized_message(
+  std::shared_ptr<rclcpp::SerializedMessage> & message)
+{
+  message.reset();
+}
+
+}  // namespace rclcpp

rclcpp/src/rclcpp/intra_process_manager.cpp

@@ -157,7 +157,13 @@ IntraProcessManager::get_subscription_intra_process(uint64_t intra_process_subsc
   if (subscription_it == subscriptions_.end()) {
     return nullptr;
   } else {
-    return subscription_it->second.subscription;
+    auto subscription = subscription_it->second.subscription.lock();
+    if (subscription) {
+      return subscription;
+    } else {
+      subscriptions_.erase(subscription_it);
+      return nullptr;
+    }
   }
 }
 

rclcpp/src/rclcpp/logger.cpp

@@ -14,6 +14,8 @@
 
 #include <string>
 
+#include "rcl_logging_interface/rcl_logging_interface.h"
+
 #include "rclcpp/exceptions.hpp"
 #include "rclcpp/logger.hpp"
 #include "rclcpp/logging.hpp"
@@ -46,6 +48,20 @@ get_node_logger(const rcl_node_t * node)
   return rclcpp::get_logger(logger_name);
 }
 
+rcpputils::fs::path
+get_logging_directory()
+{
+  char * log_dir = NULL;
+  auto allocator = rcutils_get_default_allocator();
+  rcl_logging_ret_t ret = rcl_logging_get_logging_directory(allocator, &log_dir);
+  if (RCL_LOGGING_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret);
+  }
+  std::string path{log_dir};
+  allocator.deallocate(log_dir, allocator.state);
+  return path;
+}
+
 void
 Logger::set_level(Level level)
 {

rclcpp/src/rclcpp/network_flow_endpoint.cpp

@@ -0,0 +1,84 @@
+// 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.
+
+#include <string>
+
+#include "rclcpp/network_flow_endpoint.hpp"
+
+namespace rclcpp
+{
+
+const std::string &
+NetworkFlowEndpoint::transport_protocol() const
+{
+  return transport_protocol_;
+}
+
+const std::string &
+NetworkFlowEndpoint::internet_protocol() const
+{
+  return internet_protocol_;
+}
+
+uint16_t NetworkFlowEndpoint::transport_port() const
+{
+  return transport_port_;
+}
+
+uint32_t NetworkFlowEndpoint::flow_label() const
+{
+  return flow_label_;
+}
+
+uint8_t NetworkFlowEndpoint::dscp() const
+{
+  return dscp_;
+}
+
+const std::string &
+NetworkFlowEndpoint::internet_address() const
+{
+  return internet_address_;
+}
+
+bool operator==(const NetworkFlowEndpoint & left, const NetworkFlowEndpoint & right)
+{
+  return left.transport_protocol_ == right.transport_protocol_ &&
+         left.internet_protocol_ == right.internet_protocol_ &&
+         left.transport_port_ == right.transport_port_ &&
+         left.flow_label_ == right.flow_label_ &&
+         left.dscp_ == right.dscp_ &&
+         left.internet_address_ == right.internet_address_;
+}
+
+bool operator!=(const NetworkFlowEndpoint & left, const NetworkFlowEndpoint & right)
+{
+  return !(left == right);
+}
+
+std::ostream & operator<<(std::ostream & os, const NetworkFlowEndpoint & network_flow_endpoint)
+{
+  // Stream out in JSON-like format
+  os << "{" <<
+    "\"transportProtocol\": \"" << network_flow_endpoint.transport_protocol_ << "\", " <<
+    "\"internetProtocol\": \"" << network_flow_endpoint.internet_protocol_ << "\", " <<
+    "\"transportPort\": \"" << network_flow_endpoint.transport_port_ << "\", " <<
+    "\"flowLabel\": \"" << std::to_string(network_flow_endpoint.flow_label_) << "\", " <<
+    "\"dscp\": \"" << std::to_string(network_flow_endpoint.dscp_) << "\", " <<
+    "\"internetAddress\": \"" << network_flow_endpoint.internet_address_ << "\"" <<
+    "}";
+  return os;
+}
+
+}  // namespace rclcpp

rclcpp/src/rclcpp/node.cpp

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <algorithm>
+#include <array>
 #include <limits>
 #include <map>
 #include <memory>
@@ -20,6 +21,9 @@
 #include <utility>
 #include <vector>
 
+#include "rcl/arguments.h"
+
+#include "rclcpp/detail/qos_parameters.hpp"
 #include "rclcpp/exceptions.hpp"
 #include "rclcpp/graph_listener.hpp"
 #include "rclcpp/node.hpp"
@@ -33,9 +37,12 @@
 #include "rclcpp/node_interfaces/node_timers.hpp"
 #include "rclcpp/node_interfaces/node_topics.hpp"
 #include "rclcpp/node_interfaces/node_waitables.hpp"
+#include "rclcpp/qos_overriding_options.hpp"
 
 #include "rmw/validate_namespace.h"
 
+#include "./detail/resolve_parameter_overrides.hpp"
+
 using rclcpp::Node;
 using rclcpp::NodeOptions;
 using rclcpp::exceptions::throw_from_rcl_error;
@@ -94,6 +101,45 @@ Node::Node(
 {
 }
 
+static
+rclcpp::QoS
+get_parameter_events_qos(
+  rclcpp::node_interfaces::NodeBaseInterface & node_base,
+  const rclcpp::NodeOptions & options)
+{
+  auto final_qos = options.parameter_event_qos();
+  const rcl_arguments_t * global_args = nullptr;
+  auto * rcl_options = options.get_rcl_node_options();
+  if (rcl_options->use_global_arguments) {
+    auto context_ptr = node_base.get_context()->get_rcl_context();
+    global_args = &(context_ptr->global_arguments);
+  }
+
+  auto parameter_overrides = rclcpp::detail::resolve_parameter_overrides(
+    node_base.get_fully_qualified_name(),
+    options.parameter_overrides(),
+    &rcl_options->arguments,
+    global_args);
+
+  auto final_topic_name = node_base.resolve_topic_or_service_name("/parameter_events", false);
+  auto prefix = "qos_overrides." + final_topic_name + ".";
+  std::array<rclcpp::QosPolicyKind, 4> policies = {
+    rclcpp::QosPolicyKind::Depth,
+    rclcpp::QosPolicyKind::Durability,
+    rclcpp::QosPolicyKind::History,
+    rclcpp::QosPolicyKind::Reliability,
+  };
+  for (const auto & policy : policies) {
+    auto param_name = prefix + rclcpp::qos_policy_kind_to_cstr(policy);
+    auto it = parameter_overrides.find(param_name);
+    auto value = it != parameter_overrides.end() ?
+      it->second :
+      rclcpp::detail::get_default_qos_param_value(policy, options.parameter_event_qos());
+    rclcpp::detail::apply_qos_override(policy, value, final_qos);
+  }
+  return final_qos;
+}
+
 Node::Node(
   const std::string & node_name,
   const std::string & namespace_,
@@ -126,7 +172,9 @@ Node::Node(
       options.parameter_overrides(),
       options.start_parameter_services(),
       options.start_parameter_event_publisher(),
-      options.parameter_event_qos(),
+      // This is needed in order to apply parameter overrides to the qos profile provided in
+      // options.
+      get_parameter_events_qos(*node_base_, options),
       options.parameter_event_publisher_options(),
       options.allow_undeclared_parameters(),
       options.automatically_declare_parameters_from_overrides()
@@ -139,13 +187,28 @@ Node::Node(
       node_logging_,
       node_clock_,
       node_parameters_,
-      options.clock_qos()
+      options.clock_qos(),
+      options.use_clock_thread()
     )),
   node_waitables_(new rclcpp::node_interfaces::NodeWaitables(node_base_.get())),
   node_options_(options),
   sub_namespace_(""),
   effective_namespace_(create_effective_namespace(this->get_namespace(), sub_namespace_))
 {
+  // we have got what we wanted directly from the overrides,
+  // but declare the parameters anyway so they are visible.
+  rclcpp::detail::declare_qos_parameters(
+    rclcpp::QosOverridingOptions
+  {
+    QosPolicyKind::Depth,
+    QosPolicyKind::Durability,
+    QosPolicyKind::History,
+    QosPolicyKind::Reliability,
+  },
+    node_parameters_,
+    node_topics_->resolve_topic_name("/parameter_events"),
+    options.parameter_event_qos(),
+    rclcpp::detail::PublisherQosParametersTraits{});
 }
 
 Node::Node(
@@ -185,7 +248,18 @@ Node::Node(
 }
 
 Node::~Node()
-{}
+{
+  // release sub-interfaces in an order that allows them to consult with node_base during tear-down
+  node_waitables_.reset();
+  node_time_source_.reset();
+  node_parameters_.reset();
+  node_clock_.reset();
+  node_services_.reset();
+  node_topics_.reset();
+  node_timers_.reset();
+  node_logging_.reset();
+  node_graph_.reset();
+}
 
 const char *
 Node::get_name() const
@@ -219,6 +293,24 @@ Node::create_callback_group(
   return node_base_->create_callback_group(group_type, automatically_add_to_executor_with_node);
 }
 
+const rclcpp::ParameterValue &
+Node::declare_parameter(const std::string & name)
+{
+#ifndef _WIN32
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#else
+# pragma warning(push)
+# pragma warning(disable: 4996)
+#endif
+  return this->node_parameters_->declare_parameter(name);
+#ifndef _WIN32
+# pragma GCC diagnostic pop
+#else
+# pragma warning(pop)
+#endif
+}
+
 const rclcpp::ParameterValue &
 Node::declare_parameter(
   const std::string & name,
@@ -233,6 +325,20 @@ Node::declare_parameter(
     ignore_override);
 }
 
+const rclcpp::ParameterValue &
+Node::declare_parameter(
+  const std::string & name,
+  rclcpp::ParameterType type,
+  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  bool ignore_override)
+{
+  return this->node_parameters_->declare_parameter(
+    name,
+    type,
+    parameter_descriptor,
+    ignore_override);
+}
+
 void
 Node::undeclare_parameter(const std::string & name)
 {
@@ -499,3 +605,9 @@ Node::get_node_options() const
 {
   return this->node_options_;
 }
+
+void Node::for_each_callback_group(
+  const node_interfaces::NodeBaseInterface::CallbackGroupFunction & func)
+{
+  rclcpp::node_interfaces::global_for_each_callback_group(node_base_.get(), func);
+}

rclcpp/src/rclcpp/node_interfaces/node_base.cpp

@@ -31,6 +31,8 @@ using rclcpp::exceptions::throw_from_rcl_error;
 
 using rclcpp::node_interfaces::NodeBase;
 
+using rclcpp::node_interfaces::map_of_mutexes;
+
 NodeBase::NodeBase(
   const std::string & node_name,
   const std::string & namespace_,
@@ -46,6 +48,9 @@ NodeBase::NodeBase(
   associated_with_executor_(false),
   notify_guard_condition_is_valid_(false)
 {
+  // Generate a mutex for this instance of NodeBase
+  NodeBase::map_object.create_mutex_of_nodebase(this);
+
   // Setup the guard condition that is notified when changes occur in the graph.
   rcl_guard_condition_options_t guard_condition_options = rcl_guard_condition_get_default_options();
   rcl_ret_t ret = rcl_guard_condition_init(
@@ -166,6 +171,8 @@ NodeBase::~NodeBase()
         "failed to destroy guard condition: %s", rcl_get_error_string().str);
     }
   }
+
+  NodeBase::map_object.delete_mutex_of_nodebase(this);
 }
 
 const char *
@@ -221,12 +228,11 @@ NodeBase::create_callback_group(
   rclcpp::CallbackGroupType group_type,
   bool automatically_add_to_executor_with_node)
 {
-  using rclcpp::CallbackGroup;
-  using rclcpp::CallbackGroupType;
-  auto group = CallbackGroup::SharedPtr(
-    new CallbackGroup(
-      group_type,
-      automatically_add_to_executor_with_node));
+  auto group = std::make_shared<rclcpp::CallbackGroup>(
+    group_type,
+    automatically_add_to_executor_with_node);
+  auto mutex_ptr = NodeBase::map_object.get_mutex_of_nodebase(this);
+  std::lock_guard<std::mutex> lock(*mutex_ptr);
   callback_groups_.push_back(group);
   return group;
 }
@@ -240,14 +246,16 @@ NodeBase::get_default_callback_group()
 bool
 NodeBase::callback_group_in_node(rclcpp::CallbackGroup::SharedPtr group)
 {
-  bool group_belongs_to_this_node = false;
+  auto mutex_ptr = NodeBase::map_object.get_mutex_of_nodebase(this);
+  std::lock_guard<std::mutex> lock(*mutex_ptr);
+
   for (auto & weak_group : this->callback_groups_) {
     auto cur_group = weak_group.lock();
     if (cur_group && (cur_group == group)) {
-      group_belongs_to_this_node = true;
+      return true;
     }
   }
-  return group_belongs_to_this_node;
+  return false;
 }
 
 const std::vector<rclcpp::CallbackGroup::WeakPtr> &
@@ -310,3 +318,41 @@ NodeBase::resolve_topic_or_service_name(
   allocator.deallocate(output_cstr, allocator.state);
   return output;
 }
+
+map_of_mutexes NodeBase::map_object = map_of_mutexes();
+
+void map_of_mutexes::create_mutex_of_nodebase(
+  const rclcpp::node_interfaces::NodeBaseInterface * nodebase)
+{
+  std::lock_guard<std::mutex> guard(this->internal_mutex_);
+  this->data_.emplace(nodebase, std::make_shared<std::mutex>() );
+}
+
+std::shared_ptr<std::mutex> map_of_mutexes::get_mutex_of_nodebase(
+  const rclcpp::node_interfaces::NodeBaseInterface * nodebase)
+{
+  std::lock_guard<std::mutex> guard(this->internal_mutex_);
+  return this->data_[nodebase];
+}
+
+void map_of_mutexes::delete_mutex_of_nodebase(
+  const rclcpp::node_interfaces::NodeBaseInterface * nodebase)
+{
+  std::lock_guard<std::mutex> guard(this->internal_mutex_);
+  this->data_.erase(nodebase);
+}
+
+// For each callback group free function implementation
+void rclcpp::node_interfaces::global_for_each_callback_group(
+  NodeBaseInterface * node_base_interface, const NodeBaseInterface::CallbackGroupFunction & func)
+{
+  auto mutex_ptr = NodeBase::map_object.get_mutex_of_nodebase(node_base_interface);
+  std::lock_guard<std::mutex> lock(*mutex_ptr);
+
+  for (const auto & weak_group : node_base_interface->get_callback_groups()) {
+    auto group = weak_group.lock();
+    if (group) {
+      func(group);
+    }
+  }
+}

rclcpp/src/rclcpp/node_interfaces/node_parameters.cpp

@@ -16,8 +16,10 @@
 
 #include <rcl_yaml_param_parser/parser.h>
 
+#include <array>
 #include <cmath>
 #include <cstdlib>
+#include <cstring>
 #include <functional>
 #include <limits>
 #include <map>
@@ -34,6 +36,8 @@
 #include "rcutils/logging_macros.h"
 #include "rmw/qos_profiles.h"
 
+#include "../detail/resolve_parameter_overrides.hpp"
+
 using rclcpp::node_interfaces::NodeParameters;
 
 NodeParameters::NodeParameters(
@@ -85,60 +89,27 @@ NodeParameters::NodeParameters(
     throw std::runtime_error("Need valid node options in NodeParameters");
   }
 
-  std::vector<const rcl_arguments_t *> argument_sources;
-  // global before local so that local overwrites global
+  const rcl_arguments_t * global_args = nullptr;
   if (options->use_global_arguments) {
     auto context_ptr = node_base->get_context()->get_rcl_context();
-    argument_sources.push_back(&(context_ptr->global_arguments));
+    global_args = &(context_ptr->global_arguments);
   }
-  argument_sources.push_back(&options->arguments);
-
-  // Get fully qualified node name post-remapping to use to find node's params in yaml files
   combined_name_ = node_base->get_fully_qualified_name();
 
-  for (const rcl_arguments_t * source : argument_sources) {
-    rcl_params_t * params = NULL;
-    rcl_ret_t ret = rcl_arguments_get_param_overrides(source, &params);
-    if (RCL_RET_OK != ret) {
-      rclcpp::exceptions::throw_from_rcl_error(ret);
-    }
-    if (params) {
-      auto cleanup_params = make_scope_exit(
-        [params]() {
-          rcl_yaml_node_struct_fini(params);
-        });
-      rclcpp::ParameterMap initial_map = rclcpp::parameter_map_from(params);
-
-      // Enforce wildcard matching precedence
-      // TODO(cottsay) implement further wildcard matching
-      const std::vector<std::string> node_matching_names{"/**", combined_name_};
-      for (const auto & node_name : node_matching_names) {
-        if (initial_map.count(node_name) > 0) {
-          // Combine parameter yaml files, overwriting values in older ones
-          for (const rclcpp::Parameter & param : initial_map.at(node_name)) {
-            parameter_overrides_[param.get_name()] =
-              rclcpp::ParameterValue(param.get_value_message());
-          }
-        }
-      }
-    }
-  }
-
-  // parameter overrides passed to constructor will overwrite overrides from yaml file sources
-  for (auto & param : parameter_overrides) {
-    parameter_overrides_[param.get_name()] =
-      rclcpp::ParameterValue(param.get_value_message());
-  }
+  parameter_overrides_ = rclcpp::detail::resolve_parameter_overrides(
+    combined_name_, parameter_overrides, &options->arguments, global_args);
 
   // If asked, initialize any parameters that ended up in the initial parameter values,
   // but did not get declared explcitily by this point.
   if (automatically_declare_parameters_from_overrides) {
+    rcl_interfaces::msg::ParameterDescriptor descriptor;
+    descriptor.dynamic_typing = true;
     for (const auto & pair : this->get_parameter_overrides()) {
       if (!this->has_parameter(pair.first)) {
         this->declare_parameter(
           pair.first,
           pair.second,
-          rcl_interfaces::msg::ParameterDescriptor(),
+          descriptor,
           true);
       }
     }
@@ -165,14 +136,13 @@ __are_doubles_equal(double x, double y, double ulp = 100.0)
   return std::abs(x - y) <= std::numeric_limits<double>::epsilon() * std::abs(x + y) * ulp;
 }
 
-RCLCPP_LOCAL
-inline
-void
-format_reason(std::string & reason, const std::string & name, const char * range_type)
+static
+std::string
+format_range_reason(const std::string & name, const char * range_type)
 {
   std::ostringstream ss;
   ss << "Parameter {" << name << "} doesn't comply with " << range_type << " range.";
-  reason = ss.str();
+  return ss.str();
 }
 
 RCLCPP_LOCAL
@@ -191,7 +161,7 @@ __check_parameter_value_in_range(
     }
     if ((v < integer_range.from_value) || (v > integer_range.to_value)) {
       result.successful = false;
-      format_reason(result.reason, descriptor.name, "integer");
+      result.reason = format_range_reason(descriptor.name, "integer");
       return result;
     }
     if (integer_range.step == 0) {
@@ -201,7 +171,7 @@ __check_parameter_value_in_range(
       return result;
     }
     result.successful = false;
-    format_reason(result.reason, descriptor.name, "integer");
+    result.reason = format_range_reason(descriptor.name, "integer");
     return result;
   }
 
@@ -213,7 +183,7 @@ __check_parameter_value_in_range(
     }
     if ((v < fp_range.from_value) || (v > fp_range.to_value)) {
       result.successful = false;
-      format_reason(result.reason, descriptor.name, "floating point");
+      result.reason = format_range_reason(descriptor.name, "floating point");
       return result;
     }
     if (fp_range.step == 0.0) {
@@ -224,29 +194,62 @@ __check_parameter_value_in_range(
       return result;
     }
     result.successful = false;
-    format_reason(result.reason, descriptor.name, "floating point");
+    result.reason = format_range_reason(descriptor.name, "floating point");
     return result;
   }
   return result;
 }
 
+static
+std::string
+format_type_reason(
+  const std::string & name, const std::string & old_type, const std::string & new_type)
+{
+  std::ostringstream ss;
+  // WARN: A condition later depends on this message starting with "Wrong parameter type",
+  // check `declare_parameter` if you modify this!
+  ss << "Wrong parameter type, parameter {" << name << "} is of type {" << old_type <<
+    "}, setting it to {" << new_type << "} is not allowed.";
+  return ss.str();
+}
+
 // Return true if parameter values comply with the descriptors in parameter_infos.
 RCLCPP_LOCAL
 rcl_interfaces::msg::SetParametersResult
 __check_parameters(
   std::map<std::string, rclcpp::node_interfaces::ParameterInfo> & parameter_infos,
-  const std::vector<rclcpp::Parameter> & parameters)
+  const std::vector<rclcpp::Parameter> & parameters,
+  bool allow_undeclared)
 {
   rcl_interfaces::msg::SetParametersResult result;
   result.successful = true;
   for (const rclcpp::Parameter & parameter : parameters) {
-    const rcl_interfaces::msg::ParameterDescriptor & descriptor =
-      parameter_infos[parameter.get_name()].descriptor;
+    std::string name = parameter.get_name();
+    rcl_interfaces::msg::ParameterDescriptor descriptor;
+    if (allow_undeclared) {
+      auto it = parameter_infos.find(name);
+      if (it != parameter_infos.cend()) {
+        descriptor = it->second.descriptor;
+      } else {
+        // implicitly declared parameters are dinamically typed!
+        descriptor.dynamic_typing = true;
+      }
+    } else {
+      descriptor = parameter_infos[name].descriptor;
+    }
+    const auto new_type = parameter.get_type();
+    const auto specified_type = static_cast<rclcpp::ParameterType>(descriptor.type);
+    result.successful = descriptor.dynamic_typing || specified_type == new_type;
+    if (!result.successful) {
+      result.reason = format_type_reason(
+        name, rclcpp::to_string(specified_type), rclcpp::to_string(new_type));
+      return result;
+    }
     result = __check_parameter_value_in_range(
       descriptor,
       parameter.get_parameter_value());
     if (!result.successful) {
-      break;
+      return result;
     }
   }
   return result;
@@ -293,16 +296,18 @@ __set_parameters_atomically_common(
   const std::vector<rclcpp::Parameter> & parameters,
   std::map<std::string, rclcpp::node_interfaces::ParameterInfo> & parameter_infos,
   CallbacksContainerType & callback_container,
-  const OnParametersSetCallbackType & callback)
+  const OnParametersSetCallbackType & callback,
+  bool allow_undeclared = false)
 {
-  // Call the user callback to see if the new value(s) are allowed.
-  rcl_interfaces::msg::SetParametersResult result =
-    __call_on_parameters_set_callbacks(parameters, callback_container, callback);
+  // Check if the value being set complies with the descriptor.
+  rcl_interfaces::msg::SetParametersResult result = __check_parameters(
+    parameter_infos, parameters, allow_undeclared);
   if (!result.successful) {
     return result;
   }
-  // Check if the value being set complies with the descriptor.
-  result = __check_parameters(parameter_infos, parameters);
+  // Call the user callback to see if the new value(s) are allowed.
+  result =
+    __call_on_parameters_set_callbacks(parameters, callback_container, callback);
   if (!result.successful) {
     return result;
   }
@@ -344,6 +349,21 @@ __declare_parameter_common(
     initial_value = &overrides_it->second;
   }
 
+  // If there is no initial value, then skip initialization
+  if (initial_value->get_type() == rclcpp::PARAMETER_NOT_SET) {
+    // Add declared parameters to storage (without a value)
+    parameter_infos[name].descriptor.name = name;
+    if (parameter_descriptor.dynamic_typing) {
+      parameter_infos[name].descriptor.type = rclcpp::PARAMETER_NOT_SET;
+    } else {
+      parameter_infos[name].descriptor.type = parameter_descriptor.type;
+    }
+    parameters_out[name] = parameter_infos.at(name);
+    rcl_interfaces::msg::SetParametersResult result;
+    result.successful = true;
+    return result;
+  }
+
   // Check with the user's callback to see if the initial value can be set.
   std::vector<rclcpp::Parameter> parameter_wrappers {rclcpp::Parameter(name, *initial_value)};
   // This function also takes care of default vs initial value.
@@ -353,6 +373,10 @@ __declare_parameter_common(
     callback_container,
     callback);
 
+  if (!result.successful) {
+    return result;
+  }
+
   // Add declared parameters to storage.
   parameters_out[name] = parameter_infos.at(name);
 
@@ -364,6 +388,91 @@ __declare_parameter_common(
   return result;
 }
 
+static
+const rclcpp::ParameterValue &
+declare_parameter_helper(
+  const std::string & name,
+  rclcpp::ParameterType type,
+  const rclcpp::ParameterValue & default_value,
+  rcl_interfaces::msg::ParameterDescriptor parameter_descriptor,
+  bool ignore_override,
+  std::map<std::string, rclcpp::node_interfaces::ParameterInfo> & parameters,
+  const std::map<std::string, rclcpp::ParameterValue> & overrides,
+  CallbacksContainerType & callback_container,
+  const OnParametersSetCallbackType & callback,
+  rclcpp::Publisher<rcl_interfaces::msg::ParameterEvent> * events_publisher,
+  const std::string & combined_name,
+  rclcpp::node_interfaces::NodeClockInterface & node_clock)
+{
+  // TODO(sloretz) parameter name validation
+  if (name.empty()) {
+    throw rclcpp::exceptions::InvalidParametersException("parameter name must not be empty");
+  }
+
+  // Error if this parameter has already been declared and is different
+  if (__lockless_has_parameter(parameters, name)) {
+    throw rclcpp::exceptions::ParameterAlreadyDeclaredException(
+            "parameter '" + name + "' has already been declared");
+  }
+
+  if (!parameter_descriptor.dynamic_typing) {
+    if (rclcpp::PARAMETER_NOT_SET == type) {
+      type = default_value.get_type();
+    }
+    if (rclcpp::PARAMETER_NOT_SET == type) {
+      throw rclcpp::exceptions::InvalidParameterTypeException{
+              name,
+              "cannot declare a statically typed parameter with an uninitialized value"
+      };
+    }
+    parameter_descriptor.type = static_cast<uint8_t>(type);
+  }
+
+  rcl_interfaces::msg::ParameterEvent parameter_event;
+  auto result = __declare_parameter_common(
+    name,
+    default_value,
+    parameter_descriptor,
+    parameters,
+    overrides,
+    callback_container,
+    callback,
+    &parameter_event,
+    ignore_override);
+
+  // If it failed to be set, then throw an exception.
+  if (!result.successful) {
+    constexpr const char type_error_msg_start[] = "Wrong parameter type";
+    if (
+      0u == std::strncmp(
+        result.reason.c_str(), type_error_msg_start, sizeof(type_error_msg_start) - 1))
+    {
+      // TODO(ivanpauno): Refactor the logic so we don't need the above `strncmp` and we can
+      // detect between both exceptions more elegantly.
+      throw rclcpp::exceptions::InvalidParameterTypeException(name, result.reason);
+    }
+    throw rclcpp::exceptions::InvalidParameterValueException(
+            "parameter '" + name + "' could not be set: " + result.reason);
+  }
+
+  // Publish if events_publisher_ is not nullptr, which may be if disabled in the constructor.
+  if (nullptr != events_publisher) {
+    parameter_event.node = combined_name;
+    parameter_event.stamp = node_clock.get_clock()->now();
+    events_publisher->publish(parameter_event);
+  }
+
+  return parameters.at(name).value;
+}
+
+const rclcpp::ParameterValue &
+NodeParameters::declare_parameter(const std::string & name)
+{
+  rcl_interfaces::msg::ParameterDescriptor descriptor;
+  descriptor.dynamic_typing = true;
+  return this->declare_parameter(name, rclcpp::ParameterValue{}, descriptor, false);
+}
+
 const rclcpp::ParameterValue &
 NodeParameters::declare_parameter(
   const std::string & name,
@@ -372,46 +481,57 @@ NodeParameters::declare_parameter(
   bool ignore_override)
 {
   std::lock_guard<std::recursive_mutex> lock(mutex_);
-
   ParameterMutationRecursionGuard guard(parameter_modification_enabled_);
 
-  // TODO(sloretz) parameter name validation
-  if (name.empty()) {
-    throw rclcpp::exceptions::InvalidParametersException("parameter name must not be empty");
-  }
-
-  // Error if this parameter has already been declared and is different
-  if (__lockless_has_parameter(parameters_, name)) {
-    throw rclcpp::exceptions::ParameterAlreadyDeclaredException(
-            "parameter '" + name + "' has already been declared");
-  }
-
-  rcl_interfaces::msg::ParameterEvent parameter_event;
-  auto result = __declare_parameter_common(
+  return declare_parameter_helper(
     name,
+    rclcpp::PARAMETER_NOT_SET,
     default_value,
     parameter_descriptor,
+    ignore_override,
     parameters_,
     parameter_overrides_,
     on_parameters_set_callback_container_,
     on_parameters_set_callback_,
-    &parameter_event,
-    ignore_override);
+    events_publisher_.get(),
+    combined_name_,
+    *node_clock_);
+}
 
-  // If it failed to be set, then throw an exception.
-  if (!result.successful) {
-    throw rclcpp::exceptions::InvalidParameterValueException(
-            "parameter '" + name + "' could not be set: " + result.reason);
+const rclcpp::ParameterValue &
+NodeParameters::declare_parameter(
+  const std::string & name,
+  rclcpp::ParameterType type,
+  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  bool ignore_override)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  ParameterMutationRecursionGuard guard(parameter_modification_enabled_);
+
+  if (rclcpp::PARAMETER_NOT_SET == type) {
+    throw std::invalid_argument{
+            "declare_parameter(): the provided parameter type cannot be rclcpp::PARAMETER_NOT_SET"};
   }
 
-  // Publish if events_publisher_ is not nullptr, which may be if disabled in the constructor.
-  if (nullptr != events_publisher_) {
-    parameter_event.node = combined_name_;
-    parameter_event.stamp = node_clock_->get_clock()->now();
-    events_publisher_->publish(parameter_event);
+  if (parameter_descriptor.dynamic_typing == true) {
+    throw std::invalid_argument{
+            "declare_parameter(): cannot declare parameter of specific type and pass descriptor"
+            "with `dynamic_typing=true`"};
   }
 
-  return parameters_.at(name).value;
+  return declare_parameter_helper(
+    name,
+    type,
+    rclcpp::ParameterValue{},
+    parameter_descriptor,
+    ignore_override,
+    parameters_,
+    parameter_overrides_,
+    on_parameters_set_callback_container_,
+    on_parameters_set_callback_,
+    events_publisher_.get(),
+    combined_name_,
+    *node_clock_);
 }
 
 void
@@ -431,6 +551,10 @@ NodeParameters::undeclare_parameter(const std::string & name)
     throw rclcpp::exceptions::ParameterImmutableException(
             "cannot undeclare parameter '" + name + "' because it is read-only");
   }
+  if (!parameter_info->second.descriptor.dynamic_typing) {
+    throw rclcpp::exceptions::InvalidParameterTypeException{
+            name, "cannot undeclare an statically typed parameter"};
+  }
 
   parameters_.erase(parameter_info);
 }
@@ -524,13 +648,17 @@ NodeParameters::set_parameters_atomically(const std::vector<rclcpp::Parameter> &
   rcl_interfaces::msg::ParameterEvent parameter_event_msg;
   parameter_event_msg.node = combined_name_;
   CallbacksContainerType empty_callback_container;
+
+  // Implicit declare uses dynamic type descriptor.
+  rcl_interfaces::msg::ParameterDescriptor descriptor;
+  descriptor.dynamic_typing = true;
   for (auto parameter_to_be_declared : parameters_to_be_declared) {
     // This should not throw, because we validated the name and checked that
     // the parameter was not already declared.
     result = __declare_parameter_common(
       parameter_to_be_declared->get_name(),
       parameter_to_be_declared->get_parameter_value(),
-      rcl_interfaces::msg::ParameterDescriptor(),  // Implicit declare uses default descriptor.
+      descriptor,
       staged_parameter_changes,
       parameter_overrides_,
       // Only call callbacks once below
@@ -579,6 +707,11 @@ NodeParameters::set_parameters_atomically(const std::vector<rclcpp::Parameter> &
     if (rclcpp::PARAMETER_NOT_SET == parameter.get_type()) {
       auto it = parameters_.find(parameter.get_name());
       if (it != parameters_.end() && rclcpp::PARAMETER_NOT_SET != it->second.value.get_type()) {
+        if (!it->second.descriptor.dynamic_typing) {
+          result.reason = "cannot undeclare an statically typed parameter";
+          result.successful = false;
+          return result;
+        }
         parameters_to_be_undeclared.push_back(&parameter);
       }
     }
@@ -594,7 +727,8 @@ NodeParameters::set_parameters_atomically(const std::vector<rclcpp::Parameter> &
     on_parameters_set_callback_container_,
     // These callbacks are called once. When a callback returns an unsuccessful result,
     // the remaining aren't called.
-    on_parameters_set_callback_);
+    on_parameters_set_callback_,
+    allow_undeclared_);  // allow undeclared
 
   // If not successful, then stop here.
   if (!result.successful) {
@@ -679,14 +813,21 @@ NodeParameters::get_parameters(const std::vector<std::string> & names) const
 rclcpp::Parameter
 NodeParameters::get_parameter(const std::string & name) const
 {
-  rclcpp::Parameter parameter;
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
 
-  if (get_parameter(name, parameter)) {
-    return parameter;
+  auto param_iter = parameters_.find(name);
+  if (
+    parameters_.end() != param_iter &&
+    (param_iter->second.value.get_type() != rclcpp::ParameterType::PARAMETER_NOT_SET ||
+    param_iter->second.descriptor.dynamic_typing))
+  {
+    return rclcpp::Parameter{name, param_iter->second.value};
   } else if (this->allow_undeclared_) {
-    return parameter;
-  } else {
+    return rclcpp::Parameter{};
+  } else if (parameters_.end() == param_iter) {
     throw rclcpp::exceptions::ParameterNotDeclaredException(name);
+  } else {
+    throw rclcpp::exceptions::ParameterUninitializedException(name);
   }
 }
 
@@ -828,22 +969,6 @@ NodeParameters::list_parameters(const std::vector<std::string> & prefixes, uint6
   return result;
 }
 
-struct HandleCompare
-  : public std::unary_function<OnSetParametersCallbackHandle::WeakPtr, bool>
-{
-  explicit HandleCompare(const OnSetParametersCallbackHandle * const base)
-  : base_(base) {}
-  bool operator()(const OnSetParametersCallbackHandle::WeakPtr & handle)
-  {
-    auto shared_handle = handle.lock();
-    if (base_ == shared_handle.get()) {
-      return true;
-    }
-    return false;
-  }
-  const OnSetParametersCallbackHandle * const base_;
-};
-
 void
 NodeParameters::remove_on_set_parameters_callback(
   const OnSetParametersCallbackHandle * const handle)
@@ -854,7 +979,9 @@ NodeParameters::remove_on_set_parameters_callback(
   auto it = std::find_if(
     on_parameters_set_callback_container_.begin(),
     on_parameters_set_callback_container_.end(),
-    HandleCompare(handle));
+    [handle](const auto & weak_handle) {
+      return handle == weak_handle.lock().get();
+    });
   if (it != on_parameters_set_callback_container_.end()) {
     on_parameters_set_callback_container_.erase(it);
   } else {

rclcpp/src/rclcpp/node_interfaces/node_time_source.cpp

@@ -27,7 +27,8 @@ NodeTimeSource::NodeTimeSource(
   rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging,
   rclcpp::node_interfaces::NodeClockInterface::SharedPtr node_clock,
   rclcpp::node_interfaces::NodeParametersInterface::SharedPtr node_parameters,
-  const rclcpp::QoS & qos)
+  const rclcpp::QoS & qos,
+  bool use_clock_thread)
 : node_base_(node_base),
   node_topics_(node_topics),
   node_graph_(node_graph),
@@ -35,7 +36,7 @@ NodeTimeSource::NodeTimeSource(
   node_logging_(node_logging),
   node_clock_(node_clock),
   node_parameters_(node_parameters),
-  time_source_(qos)
+  time_source_(qos, use_clock_thread)
 {
   time_source_.attachNode(
     node_base_,

rclcpp/src/rclcpp/node_interfaces/node_timers.cpp

@@ -16,6 +16,8 @@
 
 #include <string>
 
+#include "tracetools/tracetools.h"
+
 using rclcpp::node_interfaces::NodeTimers;
 
 NodeTimers::NodeTimers(rclcpp::node_interfaces::NodeBaseInterface * node_base)
@@ -44,4 +46,8 @@ NodeTimers::add_timer(
             std::string("Failed to notify wait set on timer creation: ") +
             rmw_get_error_string().str);
   }
+  TRACEPOINT(
+    rclcpp_timer_link_node,
+    static_cast<const void *>(timer->get_timer_handle().get()),
+    static_cast<const void *>(node_base_->get_rcl_node_handle()));
 }

rclcpp/src/rclcpp/node_options.cpp

@@ -78,6 +78,7 @@ NodeOptions::operator=(const NodeOptions & other)
     this->start_parameter_services_ = other.start_parameter_services_;
     this->start_parameter_event_publisher_ = other.start_parameter_event_publisher_;
     this->clock_qos_ = other.clock_qos_;
+    this->use_clock_thread_ = other.use_clock_thread_;
     this->parameter_event_qos_ = other.parameter_event_qos_;
     this->rosout_qos_ = other.rosout_qos_;
     this->parameter_event_publisher_options_ = other.parameter_event_publisher_options_;
@@ -272,6 +273,19 @@ NodeOptions::clock_qos(const rclcpp::QoS & clock_qos)
   return *this;
 }
 
+bool
+NodeOptions::use_clock_thread() const
+{
+  return this->use_clock_thread_;
+}
+
+NodeOptions &
+NodeOptions::use_clock_thread(bool use_clock_thread)
+{
+  this->use_clock_thread_ = use_clock_thread;
+  return *this;
+}
+
 const rclcpp::QoS &
 NodeOptions::parameter_event_qos() const
 {

rclcpp/src/rclcpp/parameter_client.cpp

@@ -42,7 +42,7 @@ AsyncParametersClient::AsyncParametersClient(
   if (remote_node_name != "") {
     remote_node_name_ = remote_node_name;
   } else {
-    remote_node_name_ = node_base_interface->get_name();
+    remote_node_name_ = node_base_interface->get_fully_qualified_name();
   }
 
   rcl_client_options_t options = rcl_client_get_default_options();
@@ -273,6 +273,55 @@ AsyncParametersClient::set_parameters_atomically(
   return future_result;
 }
 
+std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+AsyncParametersClient::delete_parameters(
+  const std::vector<std::string> & parameters_names)
+{
+  std::vector<rclcpp::Parameter> parameters;
+  for (const std::string & name : parameters_names) {
+    parameters.push_back(rclcpp::Parameter(name));
+  }
+  auto future_result = set_parameters(parameters);
+
+  return future_result;
+}
+
+std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+AsyncParametersClient::load_parameters(
+  const std::string & yaml_filename)
+{
+  rclcpp::ParameterMap parameter_map = rclcpp::parameter_map_from_yaml_file(yaml_filename);
+  return this->load_parameters(parameter_map);
+}
+
+std::shared_future<std::vector<rcl_interfaces::msg::SetParametersResult>>
+AsyncParametersClient::load_parameters(
+  const rclcpp::ParameterMap & parameter_map)
+{
+  std::vector<rclcpp::Parameter> parameters;
+  std::string remote_name = remote_node_name_.substr(remote_node_name_.substr(1).find("/") + 2);
+  for (const auto & params : parameter_map) {
+    std::string node_full_name = params.first;
+    std::string node_name = node_full_name.substr(node_full_name.find("/*/") + 3);
+    if (node_full_name == remote_node_name_ ||
+      node_full_name == "/**" ||
+      (node_name == remote_name))
+    {
+      for (const auto & param : params.second) {
+        parameters.push_back(param);
+      }
+    }
+  }
+
+  if (parameters.size() == 0) {
+    throw rclcpp::exceptions::InvalidParametersException("No valid parameter");
+  }
+  auto future_result = set_parameters(parameters);
+
+  return future_result;
+}
+
+
 std::shared_future<rcl_interfaces::msg::ListParametersResult>
 AsyncParametersClient::list_parameters(
   const std::vector<std::string> & prefixes,
@@ -420,6 +469,42 @@ SyncParametersClient::set_parameters(
   return std::vector<rcl_interfaces::msg::SetParametersResult>();
 }
 
+std::vector<rcl_interfaces::msg::SetParametersResult>
+SyncParametersClient::delete_parameters(
+  const std::vector<std::string> & parameters_names,
+  std::chrono::nanoseconds timeout)
+{
+  auto f = async_parameters_client_->delete_parameters(parameters_names);
+
+  using rclcpp::executors::spin_node_until_future_complete;
+  if (
+    spin_node_until_future_complete(
+      *executor_, node_base_interface_, f,
+      timeout) == rclcpp::FutureReturnCode::SUCCESS)
+  {
+    return f.get();
+  }
+  return std::vector<rcl_interfaces::msg::SetParametersResult>();
+}
+
+std::vector<rcl_interfaces::msg::SetParametersResult>
+SyncParametersClient::load_parameters(
+  const std::string & yaml_filename,
+  std::chrono::nanoseconds timeout)
+{
+  auto f = async_parameters_client_->load_parameters(yaml_filename);
+
+  using rclcpp::executors::spin_node_until_future_complete;
+  if (
+    spin_node_until_future_complete(
+      *executor_, node_base_interface_, f,
+      timeout) == rclcpp::FutureReturnCode::SUCCESS)
+  {
+    return f.get();
+  }
+  return std::vector<rcl_interfaces::msg::SetParametersResult>();
+}
+
 rcl_interfaces::msg::SetParametersResult
 SyncParametersClient::set_parameters_atomically(
   const std::vector<rclcpp::Parameter> & parameters,

rclcpp/src/rclcpp/parameter_event_handler.cpp

@@ -0,0 +1,208 @@
+// 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.
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+#include "rclcpp/parameter_event_handler.hpp"
+#include "rcpputils/join.hpp"
+
+namespace rclcpp
+{
+
+ParameterEventCallbackHandle::SharedPtr
+ParameterEventHandler::add_parameter_event_callback(
+  ParameterEventCallbackType callback)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  auto handle = std::make_shared<ParameterEventCallbackHandle>();
+  handle->callback = callback;
+  event_callbacks_.emplace_front(handle);
+
+  return handle;
+}
+
+void
+ParameterEventHandler::remove_parameter_event_callback(
+  ParameterEventCallbackHandle::SharedPtr callback_handle)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  auto it = std::find_if(
+    event_callbacks_.begin(),
+    event_callbacks_.end(),
+    [callback_handle](const auto & weak_handle) {
+      return callback_handle.get() == weak_handle.lock().get();
+    });
+  if (it != event_callbacks_.end()) {
+    event_callbacks_.erase(it);
+  } else {
+    throw std::runtime_error("Callback doesn't exist");
+  }
+}
+
+ParameterCallbackHandle::SharedPtr
+ParameterEventHandler::add_parameter_callback(
+  const std::string & parameter_name,
+  ParameterCallbackType callback,
+  const std::string & node_name)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  auto full_node_name = resolve_path(node_name);
+
+  auto handle = std::make_shared<ParameterCallbackHandle>();
+  handle->callback = callback;
+  handle->parameter_name = parameter_name;
+  handle->node_name = full_node_name;
+  // the last callback registered is executed first.
+  parameter_callbacks_[{parameter_name, full_node_name}].emplace_front(handle);
+
+  return handle;
+}
+
+void
+ParameterEventHandler::remove_parameter_callback(
+  ParameterCallbackHandle::SharedPtr callback_handle)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  auto handle = callback_handle.get();
+  auto & container = parameter_callbacks_[{handle->parameter_name, handle->node_name}];
+  auto it = std::find_if(
+    container.begin(),
+    container.end(),
+    [handle](const auto & weak_handle) {
+      return handle == weak_handle.lock().get();
+    });
+  if (it != container.end()) {
+    container.erase(it);
+    if (container.empty()) {
+      parameter_callbacks_.erase({handle->parameter_name, handle->node_name});
+    }
+  } else {
+    throw std::runtime_error("Callback doesn't exist");
+  }
+}
+
+bool
+ParameterEventHandler::get_parameter_from_event(
+  const rcl_interfaces::msg::ParameterEvent & event,
+  rclcpp::Parameter & parameter,
+  const std::string parameter_name,
+  const std::string node_name)
+{
+  if (event.node != node_name) {
+    return false;
+  }
+
+  for (auto & new_parameter : event.new_parameters) {
+    if (new_parameter.name == parameter_name) {
+      parameter = rclcpp::Parameter::from_parameter_msg(new_parameter);
+      return true;
+    }
+  }
+
+  for (auto & changed_parameter : event.changed_parameters) {
+    if (changed_parameter.name == parameter_name) {
+      parameter = rclcpp::Parameter::from_parameter_msg(changed_parameter);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+rclcpp::Parameter
+ParameterEventHandler::get_parameter_from_event(
+  const rcl_interfaces::msg::ParameterEvent & event,
+  const std::string parameter_name,
+  const std::string node_name)
+{
+  rclcpp::Parameter p;
+  if (!get_parameter_from_event(event, p, parameter_name, node_name)) {
+    throw std::runtime_error(
+            "Parameter '" + parameter_name + "' of node '" + node_name +
+            "' is not part of parameter event");
+  }
+  return p;
+}
+
+std::vector<rclcpp::Parameter>
+ParameterEventHandler::get_parameters_from_event(
+  const rcl_interfaces::msg::ParameterEvent & event)
+{
+  std::vector<rclcpp::Parameter> params;
+
+  for (auto & new_parameter : event.new_parameters) {
+    params.push_back(rclcpp::Parameter::from_parameter_msg(new_parameter));
+  }
+
+  for (auto & changed_parameter : event.changed_parameters) {
+    params.push_back(rclcpp::Parameter::from_parameter_msg(changed_parameter));
+  }
+
+  return params;
+}
+
+void
+ParameterEventHandler::event_callback(const rcl_interfaces::msg::ParameterEvent & event)
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+
+  for (auto it = parameter_callbacks_.begin(); it != parameter_callbacks_.end(); ++it) {
+    rclcpp::Parameter p;
+    if (get_parameter_from_event(event, p, it->first.first, it->first.second)) {
+      for (auto cb = it->second.begin(); cb != it->second.end(); ++cb) {
+        auto shared_handle = cb->lock();
+        if (nullptr != shared_handle) {
+          shared_handle->callback(p);
+        } else {
+          cb = it->second.erase(cb);
+        }
+      }
+    }
+  }
+
+  for (auto event_cb = event_callbacks_.begin(); event_cb != event_callbacks_.end(); ++event_cb) {
+    auto shared_event_handle = event_cb->lock();
+    if (nullptr != shared_event_handle) {
+      shared_event_handle->callback(event);
+    } else {
+      event_cb = event_callbacks_.erase(event_cb);
+    }
+  }
+}
+
+std::string
+ParameterEventHandler::resolve_path(const std::string & path)
+{
+  std::string full_path;
+
+  if (path == "") {
+    full_path = node_base_->get_fully_qualified_name();
+  } else {
+    full_path = path;
+    if (*path.begin() != '/') {
+      auto ns = node_base_->get_namespace();
+      const std::vector<std::string> paths{ns, path};
+      full_path = (ns == std::string("/")) ? ns + path : rcpputils::join(paths, "/");
+    }
+  }
+
+  return full_path;
+}
+
+}  // namespace rclcpp

rclcpp/src/rclcpp/parameter_events_filter.cpp

@@ -14,6 +14,7 @@
 
 #include "rclcpp/parameter_events_filter.hpp"
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -22,7 +23,7 @@ using EventType = rclcpp::ParameterEventsFilter::EventType;
 using EventPair = rclcpp::ParameterEventsFilter::EventPair;
 
 ParameterEventsFilter::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)
 : event_(event)

rclcpp/src/rclcpp/parameter_map.cpp

@@ -126,3 +126,15 @@ rclcpp::parameter_value_from(const rcl_variant_t * const c_param_value)
 
   throw InvalidParameterValueException("No parameter value set");
 }
+
+ParameterMap
+rclcpp::parameter_map_from_yaml_file(const std::string & yaml_filename)
+{
+  rcutils_allocator_t allocator = rcutils_get_default_allocator();
+  rcl_params_t * rcl_parameters = rcl_yaml_node_struct_init(allocator);
+  const char * path = yaml_filename.c_str();
+  if (!rcl_parse_yaml_file(path, rcl_parameters)) {
+    rclcpp::exceptions::throw_from_rcl_error(RCL_RET_ERROR);
+  }
+  return rclcpp::parameter_map_from(rcl_parameters);
+}

rclcpp/src/rclcpp/parameter_service.cpp

@@ -41,12 +41,13 @@ ParameterService::ParameterService(
       const std::shared_ptr<rcl_interfaces::srv::GetParameters::Request> request,
       std::shared_ptr<rcl_interfaces::srv::GetParameters::Response> response)
     {
-      for (const auto & name : request->names) {
-        // Default construct param to NOT_SET
-        rclcpp::Parameter param;
-        node_params->get_parameter(name, param);
-        // push back NOT_SET when get_parameter() call fails
-        response->values.push_back(param.get_value_message());
+      try {
+        auto parameters = node_params->get_parameters(request->names);
+        for (const auto & param : parameters) {
+          response->values.push_back(param.get_value_message());
+        }
+      } catch (const rclcpp::exceptions::ParameterNotDeclaredException & ex) {
+        RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "Failed to get parameters: %s", ex.what());
       }
     },
     qos_profile, nullptr);
@@ -67,7 +68,7 @@ ParameterService::ParameterService(
             return static_cast<rclcpp::ParameterType>(type);
           });
       } catch (const rclcpp::exceptions::ParameterNotDeclaredException & ex) {
-        RCLCPP_WARN(rclcpp::get_logger("rclcpp"), "Failed to get parameter types: %s", ex.what());
+        RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "Failed to get parameter types: %s", ex.what());
       }
     },
     qos_profile, nullptr);
@@ -88,7 +89,7 @@ ParameterService::ParameterService(
           result = node_params->set_parameters_atomically(
             {rclcpp::Parameter::from_parameter_msg(p)});
         } catch (const rclcpp::exceptions::ParameterNotDeclaredException & ex) {
-          RCLCPP_WARN(rclcpp::get_logger("rclcpp"), "Failed to set parameter: %s", ex.what());
+          RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "Failed to set parameter: %s", ex.what());
           result.successful = false;
           result.reason = ex.what();
         }
@@ -116,7 +117,7 @@ ParameterService::ParameterService(
         auto result = node_params->set_parameters_atomically(pvariants);
         response->result = result;
       } catch (const rclcpp::exceptions::ParameterNotDeclaredException & ex) {
-        RCLCPP_WARN(
+        RCLCPP_DEBUG(
           rclcpp::get_logger("rclcpp"), "Failed to set parameters atomically: %s", ex.what());
         response->result.successful = false;
         response->result.reason = "One or more parameters were not declared before setting";
@@ -136,7 +137,7 @@ ParameterService::ParameterService(
         auto descriptors = node_params->describe_parameters(request->names);
         response->descriptors = descriptors;
       } catch (const rclcpp::exceptions::ParameterNotDeclaredException & ex) {
-        RCLCPP_WARN(rclcpp::get_logger("rclcpp"), "Failed to describe parameters: %s", ex.what());
+        RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "Failed to describe parameters: %s", ex.what());
       }
     },
     qos_profile, nullptr);

rclcpp/src/rclcpp/parameter_value.cpp

@@ -67,7 +67,7 @@ array_to_string(
   type_array << "[";
   type_array.setf(format_flags, std::ios_base::basefield | std::ios::boolalpha);
   type_array << std::showbase;
-  for (const ValType value : array) {
+  for (const ValType & value : array) {
     if (!first_item) {
       type_array << ", ";
     } else {

rclcpp/src/rclcpp/publisher_base.cpp

@@ -34,6 +34,7 @@
 #include "rclcpp/experimental/intra_process_manager.hpp"
 #include "rclcpp/logging.hpp"
 #include "rclcpp/macros.hpp"
+#include "rclcpp/network_flow_endpoint.hpp"
 #include "rclcpp/node.hpp"
 #include "rclcpp/qos_event.hpp"
 
@@ -268,3 +269,39 @@ PublisherBase::default_incompatible_qos_callback(
     get_topic_name(),
     policy_name.c_str());
 }
+
+std::vector<rclcpp::NetworkFlowEndpoint> PublisherBase::get_network_flow_endpoints() const
+{
+  rcutils_allocator_t allocator = rcutils_get_default_allocator();
+  rcl_network_flow_endpoint_array_t network_flow_endpoint_array =
+    rcl_get_zero_initialized_network_flow_endpoint_array();
+  rcl_ret_t ret = rcl_publisher_get_network_flow_endpoints(
+    publisher_handle_.get(), &allocator, &network_flow_endpoint_array);
+  if (RCL_RET_OK != ret) {
+    auto error_msg = std::string("error obtaining network flows of publisher: ") +
+      rcl_get_error_string().str;
+    rcl_reset_error();
+    if (RCL_RET_OK !=
+      rcl_network_flow_endpoint_array_fini(&network_flow_endpoint_array))
+    {
+      error_msg += std::string(", also error cleaning up network flow array: ") +
+        rcl_get_error_string().str;
+      rcl_reset_error();
+    }
+    rclcpp::exceptions::throw_from_rcl_error(ret, error_msg);
+  }
+
+  std::vector<rclcpp::NetworkFlowEndpoint> network_flow_endpoint_vector;
+  for (size_t i = 0; i < network_flow_endpoint_array.size; ++i) {
+    network_flow_endpoint_vector.push_back(
+      rclcpp::NetworkFlowEndpoint(
+        network_flow_endpoint_array.network_flow_endpoint[i]));
+  }
+
+  ret = rcl_network_flow_endpoint_array_fini(&network_flow_endpoint_array);
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret, "error cleaning up network flow array");
+  }
+
+  return network_flow_endpoint_vector;
+}

rclcpp/src/rclcpp/qos.cpp

@@ -16,7 +16,9 @@
 
 #include <string>
 
+#include "rmw/error_handling.h"
 #include "rmw/types.h"
+#include "rmw/qos_profiles.h"
 
 namespace rclcpp
 {
@@ -309,6 +311,45 @@ bool operator!=(const QoS & left, const QoS & right)
   return !(left == right);
 }
 
+QoSCheckCompatibleResult
+qos_check_compatible(const QoS & publisher_qos, const QoS & subscription_qos)
+{
+  rmw_qos_compatibility_type_t compatible;
+  const size_t reason_size = 2048u;
+  char reason_c_str[reason_size] = "";
+  rmw_ret_t ret = rmw_qos_profile_check_compatible(
+    publisher_qos.get_rmw_qos_profile(),
+    subscription_qos.get_rmw_qos_profile(),
+    &compatible,
+    reason_c_str,
+    reason_size);
+  if (RMW_RET_OK != ret) {
+    std::string error_str(rmw_get_error_string().str);
+    rmw_reset_error();
+    throw rclcpp::exceptions::QoSCheckCompatibleException{error_str};
+  }
+
+  QoSCheckCompatibleResult result;
+  result.reason = std::string(reason_c_str);
+
+  switch (compatible) {
+    case RMW_QOS_COMPATIBILITY_OK:
+      result.compatibility = QoSCompatibility::Ok;
+      break;
+    case RMW_QOS_COMPATIBILITY_WARNING:
+      result.compatibility = QoSCompatibility::Warning;
+      break;
+    case RMW_QOS_COMPATIBILITY_ERROR:
+      result.compatibility = QoSCompatibility::Error;
+      break;
+    default:
+      throw rclcpp::exceptions::QoSCheckCompatibleException{
+              "Unexpected compatibility value returned by rmw '" + std::to_string(compatible) +
+              "'"};
+  }
+  return result;
+}
+
 ClockQoS::ClockQoS(const QoSInitialization & qos_initialization)
 // Using `rmw_qos_profile_sensor_data` intentionally.
 // It's best effort and `qos_initialization` is overriding the depth to 1.

rclcpp/src/rclcpp/subscription_base.cpp

@@ -288,3 +288,40 @@ SubscriptionBase::exchange_in_use_by_wait_set_state(
   }
   throw std::runtime_error("given pointer_to_subscription_part does not match any part");
 }
+
+std::vector<rclcpp::NetworkFlowEndpoint> SubscriptionBase::get_network_flow_endpoints() const
+{
+  rcutils_allocator_t allocator = rcutils_get_default_allocator();
+  rcl_network_flow_endpoint_array_t network_flow_endpoint_array =
+    rcl_get_zero_initialized_network_flow_endpoint_array();
+  rcl_ret_t ret = rcl_subscription_get_network_flow_endpoints(
+    subscription_handle_.get(), &allocator, &network_flow_endpoint_array);
+  if (RCL_RET_OK != ret) {
+    auto error_msg = std::string("Error obtaining network flows of subscription: ") +
+      rcl_get_error_string().str;
+    rcl_reset_error();
+    if (RCL_RET_OK !=
+      rcl_network_flow_endpoint_array_fini(&network_flow_endpoint_array))
+    {
+      error_msg += std::string(". Also error cleaning up network flow array: ") +
+        rcl_get_error_string().str;
+      rcl_reset_error();
+    }
+    rclcpp::exceptions::throw_from_rcl_error(ret, error_msg);
+  }
+
+  std::vector<rclcpp::NetworkFlowEndpoint> network_flow_endpoint_vector;
+  for (size_t i = 0; i < network_flow_endpoint_array.size; ++i) {
+    network_flow_endpoint_vector.push_back(
+      rclcpp::NetworkFlowEndpoint(
+        network_flow_endpoint_array.
+        network_flow_endpoint[i]));
+  }
+
+  ret = rcl_network_flow_endpoint_array_fini(&network_flow_endpoint_array);
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret, "error cleaning up network flow array");
+  }
+
+  return network_flow_endpoint_vector;
+}

rclcpp/src/rclcpp/time_source.cpp

@@ -33,21 +33,29 @@
 namespace rclcpp
 {
 
-TimeSource::TimeSource(std::shared_ptr<rclcpp::Node> node, const rclcpp::QoS & qos)
-: logger_(rclcpp::get_logger("rclcpp")),
+TimeSource::TimeSource(
+  std::shared_ptr<rclcpp::Node> node,
+  const rclcpp::QoS & qos,
+  bool use_clock_thread)
+: use_clock_thread_(use_clock_thread),
+  logger_(rclcpp::get_logger("rclcpp")),
   qos_(qos)
 {
   this->attachNode(node);
 }
 
-TimeSource::TimeSource(const rclcpp::QoS & qos)
-: logger_(rclcpp::get_logger("rclcpp")),
+TimeSource::TimeSource(
+  const rclcpp::QoS & qos,
+  bool use_clock_thread)
+: use_clock_thread_(use_clock_thread),
+  logger_(rclcpp::get_logger("rclcpp")),
   qos_(qos)
 {
 }
 
 void TimeSource::attachNode(rclcpp::Node::SharedPtr node)
 {
+  use_clock_thread_ = node->get_node_options().use_clock_thread();
   attachNode(
     node->get_node_base_interface(),
     node->get_node_topics_interface(),
@@ -127,7 +135,7 @@ void TimeSource::attachNode(
 void TimeSource::detachNode()
 {
   this->ros_time_active_ = false;
-  clock_subscription_.reset();
+  destroy_clock_sub();
   parameter_subscription_.reset();
   node_base_.reset();
   node_topics_.reset();
@@ -208,7 +216,7 @@ void TimeSource::set_clock(
   }
 }
 
-void TimeSource::clock_cb(const rosgraph_msgs::msg::Clock::SharedPtr msg)
+void TimeSource::clock_cb(std::shared_ptr<const rosgraph_msgs::msg::Clock> msg)
 {
   if (!this->ros_time_active_ && SET_TRUE == this->parameter_state_) {
     enable_ros_time();
@@ -233,21 +241,61 @@ void TimeSource::create_clock_sub()
     return;
   }
 
+  rclcpp::SubscriptionOptions options;
+  options.qos_overriding_options = rclcpp::QosOverridingOptions(
+    {
+      rclcpp::QosPolicyKind::Depth,
+      rclcpp::QosPolicyKind::Durability,
+      rclcpp::QosPolicyKind::History,
+      rclcpp::QosPolicyKind::Reliability,
+    });
+
+  if (use_clock_thread_) {
+    clock_callback_group_ = node_base_->create_callback_group(
+      rclcpp::CallbackGroupType::MutuallyExclusive,
+      false
+    );
+    options.callback_group = clock_callback_group_;
+    rclcpp::ExecutorOptions exec_options;
+    exec_options.context = node_base_->get_context();
+    clock_executor_ =
+      std::make_shared<rclcpp::executors::SingleThreadedExecutor>(exec_options);
+    if (!clock_executor_thread_.joinable()) {
+      cancel_clock_executor_promise_ = std::promise<void>{};
+      clock_executor_thread_ = std::thread(
+        [this]() {
+          auto future = cancel_clock_executor_promise_.get_future();
+          clock_executor_->add_callback_group(clock_callback_group_, node_base_);
+          clock_executor_->spin_until_future_complete(future);
+        }
+      );
+    }
+  }
+
   clock_subscription_ = rclcpp::create_subscription<rosgraph_msgs::msg::Clock>(
+    node_parameters_,
     node_topics_,
     "/clock",
     rclcpp::QoS(KeepLast(1)).best_effort(),
-    std::bind(&TimeSource::clock_cb, this, std::placeholders::_1)
+    std::bind(&TimeSource::clock_cb, this, std::placeholders::_1),
+    options
   );
 }
 
 void TimeSource::destroy_clock_sub()
 {
   std::lock_guard<std::mutex> guard(clock_sub_lock_);
+  if (clock_executor_thread_.joinable()) {
+    cancel_clock_executor_promise_.set_value();
+    clock_executor_->cancel();
+    clock_executor_thread_.join();
+    clock_executor_->remove_callback_group(clock_callback_group_);
+  }
   clock_subscription_.reset();
 }
 
-void TimeSource::on_parameter_event(const rcl_interfaces::msg::ParameterEvent::SharedPtr event)
+void TimeSource::on_parameter_event(
+  std::shared_ptr<const rcl_interfaces::msg::ParameterEvent> event)
 {
   // Filter out events on 'use_sim_time' parameter instances in other nodes.
   if (event->node != node_base_->get_fully_qualified_name()) {

rclcpp/src/rclcpp/typesupport_helpers.cpp

@@ -0,0 +1,136 @@
+// 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.
+
+#include "rclcpp/typesupport_helpers.hpp"
+
+#include <functional>
+#include <memory>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <tuple>
+#include <utility>
+
+#include "ament_index_cpp/get_package_prefix.hpp"
+#include "ament_index_cpp/get_resources.hpp"
+#include "rcpputils/shared_library.hpp"
+#include "rcpputils/find_library.hpp"
+#include "rosidl_runtime_cpp/message_type_support_decl.hpp"
+
+namespace rclcpp
+{
+
+namespace
+{
+
+// Look for the library in the ament prefix paths.
+std::string get_typesupport_library_path(
+  const std::string & package_name, const std::string & typesupport_identifier)
+{
+  const char * dynamic_library_folder;
+#ifdef _WIN32
+  dynamic_library_folder = "/bin/";
+#elif __APPLE__
+  dynamic_library_folder = "/lib/";
+#else
+  dynamic_library_folder = "/lib/";
+#endif
+
+  std::string package_prefix;
+  try {
+    package_prefix = ament_index_cpp::get_package_prefix(package_name);
+  } catch (ament_index_cpp::PackageNotFoundError & e) {
+    throw std::runtime_error(e.what());
+  }
+
+  const std::string library_path = rcpputils::path_for_library(
+    package_prefix + dynamic_library_folder,
+    package_name + "__" + typesupport_identifier);
+  if (library_path.empty()) {
+    throw std::runtime_error(
+            "Typesupport library for " + package_name + " does not exist in '" + package_prefix +
+            "'.");
+  }
+  return library_path;
+}
+
+std::tuple<std::string, std::string, std::string>
+extract_type_identifier(const std::string & full_type)
+{
+  char type_separator = '/';
+  auto sep_position_back = full_type.find_last_of(type_separator);
+  auto sep_position_front = full_type.find_first_of(type_separator);
+  if (sep_position_back == std::string::npos ||
+    sep_position_back == 0 ||
+    sep_position_back == full_type.length() - 1)
+  {
+    throw std::runtime_error(
+            "Message type is not of the form package/type and cannot be processed");
+  }
+
+  std::string package_name = full_type.substr(0, sep_position_front);
+  std::string middle_module = "";
+  if (sep_position_back - sep_position_front > 0) {
+    middle_module =
+      full_type.substr(sep_position_front + 1, sep_position_back - sep_position_front - 1);
+  }
+  std::string type_name = full_type.substr(sep_position_back + 1);
+
+  return std::make_tuple(package_name, middle_module, type_name);
+}
+
+}  // anonymous namespace
+
+std::shared_ptr<rcpputils::SharedLibrary>
+get_typesupport_library(const std::string & type, const std::string & typesupport_identifier)
+{
+  auto package_name = std::get<0>(extract_type_identifier(type));
+  auto library_path = get_typesupport_library_path(package_name, typesupport_identifier);
+  return std::make_shared<rcpputils::SharedLibrary>(library_path);
+}
+
+const rosidl_message_type_support_t *
+get_typesupport_handle(
+  const std::string & type,
+  const std::string & typesupport_identifier,
+  rcpputils::SharedLibrary & library)
+{
+  std::string package_name;
+  std::string middle_module;
+  std::string type_name;
+  std::tie(package_name, middle_module, type_name) = extract_type_identifier(type);
+
+  auto mk_error = [&package_name, &type_name](auto reason) {
+      std::stringstream rcutils_dynamic_loading_error;
+      rcutils_dynamic_loading_error <<
+        "Something went wrong loading the typesupport library for message type " << package_name <<
+        "/" << type_name << ". " << reason;
+      return rcutils_dynamic_loading_error.str();
+    };
+
+  try {
+    std::string symbol_name = typesupport_identifier + "__get_message_type_support_handle__" +
+      package_name + "__" + (middle_module.empty() ? "msg" : middle_module) + "__" + type_name;
+
+    const rosidl_message_type_support_t * (* get_ts)() = nullptr;
+    // This will throw runtime_error if the symbol was not found.
+    get_ts = reinterpret_cast<decltype(get_ts)>(library.get_symbol(symbol_name));
+    return get_ts();
+  } catch (std::runtime_error &) {
+    throw std::runtime_error{mk_error("Library could not be found.")};
+  }
+}
+
+}  // namespace rclcpp

rclcpp/test/CMakeLists.txt

@@ -4,6 +4,8 @@ find_package(test_msgs REQUIRED)
 
 include(cmake/rclcpp_add_build_failure_test.cmake)
 
+set(TEST_RESOURCES_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/resources")
+
 add_subdirectory(benchmark)
 add_subdirectory(rclcpp)
 
@@ -11,8 +13,3 @@ ament_add_gtest(test_rclcpp_gtest_macros utils/test_rclcpp_gtest_macros.cpp)
 if(TARGET test_rclcpp_gtest_macros)
   target_link_libraries(test_rclcpp_gtest_macros ${PROJECT_NAME})
 endif()
-
-# Install test resources
-install(
-  DIRECTORY resources
-  DESTINATION ${CMAKE_CURRENT_BINARY_DIR})

rclcpp/test/benchmark/benchmark_executor.cpp

@@ -42,7 +42,7 @@ public:
         nodes[i]->create_publisher<test_msgs::msg::Empty>(
           "/empty_msgs_" + std::to_string(i), rclcpp::QoS(10)));
 
-      auto callback = [this](test_msgs::msg::Empty::SharedPtr) {this->callback_count++;};
+      auto callback = [this](test_msgs::msg::Empty::ConstSharedPtr) {this->callback_count++;};
       subscriptions.push_back(
         nodes[i]->create_subscription<test_msgs::msg::Empty>(
           "/empty_msgs_" + std::to_string(i), rclcpp::QoS(10), std::move(callback)));

rclcpp/test/benchmark/benchmark_node.cpp

@@ -46,7 +46,9 @@ BENCHMARK_F(NodePerformanceTest, create_node)(benchmark::State & state)
   for (auto _ : state) {
     // Using pointer to separate construction and destruction in timing
     auto node = std::make_shared<rclcpp::Node>("node");
+#ifndef __clang_analyzer__
     benchmark::DoNotOptimize(node);
+#endif
     benchmark::ClobberMemory();
 
     // Ensure destruction of node is not counted toward timing
@@ -69,7 +71,9 @@ BENCHMARK_F(NodePerformanceTest, destroy_node)(benchmark::State & state)
     auto node = std::make_shared<rclcpp::Node>("node");
     state.ResumeTiming();
 
+#ifndef __clang_analyzer__
     benchmark::DoNotOptimize(node);
+#endif
     benchmark::ClobberMemory();
 
     node.reset();

rclcpp/test/benchmark/benchmark_node_parameters_interface.cpp

@@ -30,6 +30,7 @@ public:
     param2_name(param_prefix + ".my_param_2"),
     param3_name(param_prefix + ".my_param_3")
   {
+    dynamically_typed_descriptor.dynamic_typing = true;
   }
 
   void SetUp(benchmark::State & state)
@@ -37,9 +38,12 @@ public:
     rclcpp::init(0, nullptr);
     node = std::make_shared<rclcpp::Node>(node_name);
 
-    node->declare_parameter(param1_name);
-    node->declare_parameter(param2_name);
-    node->declare_parameter(param3_name);
+    node->declare_parameter(
+      param1_name, rclcpp::ParameterValue{}, dynamically_typed_descriptor);
+    node->declare_parameter(
+      param2_name, rclcpp::ParameterValue{}, dynamically_typed_descriptor);
+    node->declare_parameter(
+      param3_name, rclcpp::ParameterValue{}, dynamically_typed_descriptor);
     node->undeclare_parameter(param3_name);
 
     performance_test_fixture::PerformanceTest::SetUp(state);
@@ -58,6 +62,7 @@ public:
   const std::string param1_name;
   const std::string param2_name;
   const std::string param3_name;
+  rcl_interfaces::msg::ParameterDescriptor dynamically_typed_descriptor;
 
 protected:
   rclcpp::Node::SharedPtr node;
@@ -66,7 +71,7 @@ protected:
 BENCHMARK_F(NodeParametersInterfaceTest, declare_undeclare)(benchmark::State & state)
 {
   for (auto _ : state) {
-    node->declare_parameter(param3_name);
+    node->declare_parameter(param3_name, rclcpp::ParameterValue{}, dynamically_typed_descriptor);
     node->undeclare_parameter(param3_name);
   }
 }

rclcpp/test/benchmark/benchmark_parameter_client.cpp

@@ -91,11 +91,14 @@ public:
     rclcpp::init(0, nullptr);
     node = std::make_shared<rclcpp::Node>(node_name);
 
+    rcl_interfaces::msg::ParameterDescriptor descriptor;
+    descriptor.dynamic_typing = true;
+
     remote_node->declare_parameter(
-      param1_name, rclcpp::ParameterValue("param1_value"));
+      param1_name, rclcpp::ParameterValue("param1_value"), descriptor);
     remote_node->declare_parameter(
-      param2_name, rclcpp::ParameterValue(std::vector<int> {1, 2, 3}));
-    remote_node->declare_parameter(param3_name);
+      param2_name, rclcpp::ParameterValue(std::vector<int> {1, 2, 3}), descriptor);
+    remote_node->declare_parameter(param3_name, rclcpp::ParameterValue{}, descriptor);
     remote_node->undeclare_parameter(param3_name);
 
     params_client = std::make_shared<rclcpp::SyncParametersClient>(node, remote_node_name);

rclcpp/test/rclcpp/CMakeLists.txt

@@ -2,7 +2,7 @@ find_package(ament_cmake_gtest REQUIRED)
 
 find_package(rmw_implementation_cmake REQUIRED)
 
-add_definitions(-DTEST_RESOURCES_DIRECTORY="${CMAKE_CURRENT_BINARY_DIR}/../resources")
+add_definitions(-DTEST_RESOURCES_DIRECTORY="${TEST_RESOURCES_DIRECTORY}")
 
 rosidl_generate_interfaces(${PROJECT_NAME}_test_msgs
   ../msg/Header.msg
@@ -143,6 +143,13 @@ if(TARGET test_intra_process_manager)
   )
   target_link_libraries(test_intra_process_manager ${PROJECT_NAME})
 endif()
+ament_add_gmock(test_intra_process_manager_with_allocators test_intra_process_manager_with_allocators.cpp)
+if(TARGET test_intra_process_manager_with_allocators)
+  ament_target_dependencies(test_intra_process_manager_with_allocators
+    "test_msgs"
+  )
+  target_link_libraries(test_intra_process_manager_with_allocators ${PROJECT_NAME})
+endif()
 ament_add_gtest(test_ring_buffer_implementation test_ring_buffer_implementation.cpp)
 if(TARGET test_ring_buffer_implementation)
   ament_target_dependencies(test_ring_buffer_implementation
@@ -323,6 +330,16 @@ if(TARGET test_parameter)
   )
   target_link_libraries(test_parameter ${PROJECT_NAME})
 endif()
+ament_add_gtest(test_parameter_event_handler test_parameter_event_handler.cpp)
+if(TARGET test_parameter_event_handler)
+  ament_target_dependencies(test_parameter_event_handler
+    "rcl_interfaces"
+    "rmw"
+    "rosidl_generator_cpp"
+    "rosidl_typesupport_cpp"
+  )
+  target_link_libraries(test_parameter_event_handler ${PROJECT_NAME})
+endif()
 ament_add_gtest(test_parameter_map test_parameter_map.cpp)
 if(TARGET test_parameter_map)
   target_link_libraries(test_parameter_map ${PROJECT_NAME})
@@ -358,6 +375,21 @@ if(TARGET test_qos)
     ${PROJECT_NAME}
   )
 endif()
+function(test_generic_pubsub_for_rmw_implementation)
+  set(rmw_implementation_env_var RMW_IMPLEMENTATION=${rmw_implementation})
+  ament_add_gmock(test_generic_pubsub${target_suffix} test_generic_pubsub.cpp
+    ENV ${rmw_implementation_env_var}
+  )
+  if(TARGET test_generic_pubsub${target_suffix})
+    target_link_libraries(test_generic_pubsub${target_suffix} ${PROJECT_NAME})
+    ament_target_dependencies(test_generic_pubsub${target_suffix}
+      "rcpputils"
+      "rosidl_typesupport_cpp"
+      "test_msgs"
+    )
+  endif()
+endfunction()
+call_for_each_rmw_implementation(test_generic_pubsub_for_rmw_implementation)
 ament_add_gtest(test_qos_event test_qos_event.cpp)
 if(TARGET test_qos_event)
   ament_target_dependencies(test_qos_event
@@ -463,6 +495,10 @@ if(TARGET test_type_support)
   )
   target_link_libraries(test_type_support ${PROJECT_NAME})
 endif()
+ament_add_gmock(test_typesupport_helpers test_typesupport_helpers.cpp)
+if(TARGET test_typesupport_helpers)
+  target_link_libraries(test_typesupport_helpers ${PROJECT_NAME})
+endif()
 ament_add_gtest(test_find_weak_nodes test_find_weak_nodes.cpp)
 if(TARGET test_find_weak_nodes)
   ament_target_dependencies(test_find_weak_nodes
@@ -529,12 +565,11 @@ if(TARGET test_utilities)
   target_link_libraries(test_utilities ${PROJECT_NAME} mimick)
 endif()
 
-ament_add_gtest(test_init 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})
+ament_add_gtest(test_wait_for_message test_wait_for_message.cpp)
+if(TARGET test_wait_for_message)
+  ament_target_dependencies(test_wait_for_message
+    "test_msgs")
+  target_link_libraries(test_wait_for_message ${PROJECT_NAME})
 endif()
 
 ament_add_gtest(test_interface_traits test_interface_traits.cpp

rclcpp/test/rclcpp/executors/test_executors.cpp

@@ -62,7 +62,7 @@ public:
 
     const std::string topic_name = std::string("topic_") + test_name.str();
     publisher = node->create_publisher<test_msgs::msg::Empty>(topic_name, rclcpp::QoS(10));
-    auto callback = [this](test_msgs::msg::Empty::SharedPtr) {this->callback_count++;};
+    auto callback = [this](test_msgs::msg::Empty::ConstSharedPtr) {this->callback_count++;};
     subscription =
       node->create_subscription<test_msgs::msg::Empty>(
       topic_name, rclcpp::QoS(10), std::move(callback));
@@ -349,6 +349,190 @@ TYPED_TEST(TestExecutors, testSpinUntilFutureCompleteWithTimeout) {
   spinner.join();
 }
 
+class TestWaitable : public rclcpp::Waitable
+{
+public:
+  TestWaitable()
+  {
+    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_,
+      rclcpp::contexts::get_global_default_context()->get_rcl_context().get(),
+      guard_condition_options);
+    if (RCL_RET_OK != ret) {
+      rclcpp::exceptions::throw_from_rcl_error(ret);
+    }
+  }
+
+  ~TestWaitable()
+  {
+    rcl_ret_t ret = rcl_guard_condition_fini(&gc_);
+    if (RCL_RET_OK != ret) {
+      fprintf(stderr, "failed to call rcl_guard_condition_fini\n");
+    }
+  }
+
+  bool
+  add_to_wait_set(rcl_wait_set_t * wait_set) override
+  {
+    rcl_ret_t ret = rcl_wait_set_add_guard_condition(wait_set, &gc_, NULL);
+    return RCL_RET_OK == ret;
+  }
+
+  bool trigger()
+  {
+    rcl_ret_t ret = rcl_trigger_guard_condition(&gc_);
+    return RCL_RET_OK == ret;
+  }
+
+  bool
+  is_ready(rcl_wait_set_t * wait_set) override
+  {
+    (void)wait_set;
+    return true;
+  }
+
+  std::shared_ptr<void>
+  take_data() override
+  {
+    return nullptr;
+  }
+
+  void
+  execute(std::shared_ptr<void> & data) override
+  {
+    (void) data;
+    count_++;
+    std::this_thread::sleep_for(3ms);
+  }
+
+  size_t
+  get_number_of_ready_guard_conditions() override {return 1;}
+
+  size_t
+  get_count()
+  {
+    return count_;
+  }
+
+private:
+  size_t count_ = 0;
+  rcl_guard_condition_t gc_;
+};
+
+TYPED_TEST(TestExecutors, spinAll) {
+  using ExecutorType = TypeParam;
+  ExecutorType executor;
+  auto waitable_interfaces = this->node->get_node_waitables_interface();
+  auto my_waitable = std::make_shared<TestWaitable>();
+  waitable_interfaces->add_waitable(my_waitable, nullptr);
+  executor.add_node(this->node);
+
+  // Long timeout, but should not block test if spin_all works as expected as we cancel the
+  // executor.
+  bool spin_exited = false;
+  std::thread spinner([&spin_exited, &executor, this]() {
+      executor.spin_all(1s);
+      executor.remove_node(this->node, true);
+      spin_exited = true;
+    });
+
+  // Do some work until sufficient calls to the waitable occur
+  auto start = std::chrono::steady_clock::now();
+  while (
+    my_waitable->get_count() <= 1 &&
+    !spin_exited &&
+    (std::chrono::steady_clock::now() - start < 1s))
+  {
+    my_waitable->trigger();
+    this->publisher->publish(test_msgs::msg::Empty());
+    std::this_thread::sleep_for(1ms);
+  }
+
+  executor.cancel();
+  start = std::chrono::steady_clock::now();
+  while (!spin_exited && (std::chrono::steady_clock::now() - start) < 1s) {
+    std::this_thread::sleep_for(1ms);
+  }
+
+  EXPECT_LT(1u, my_waitable->get_count());
+  waitable_interfaces->remove_waitable(my_waitable, nullptr);
+  ASSERT_TRUE(spin_exited);
+  spinner.join();
+}
+
+TYPED_TEST(TestExecutors, spinSome) {
+  using ExecutorType = TypeParam;
+  ExecutorType executor;
+  auto waitable_interfaces = this->node->get_node_waitables_interface();
+  auto my_waitable = std::make_shared<TestWaitable>();
+  waitable_interfaces->add_waitable(my_waitable, nullptr);
+  executor.add_node(this->node);
+
+  // Long timeout, doesn't block test from finishing because spin_some should exit after the
+  // first one completes.
+  bool spin_exited = false;
+  std::thread spinner([&spin_exited, &executor, this]() {
+      executor.spin_some(1s);
+      executor.remove_node(this->node, true);
+      spin_exited = true;
+    });
+
+  // Do some work until sufficient calls to the waitable occur, but keep going until either
+  // count becomes too large, spin exits, or the 1 second timeout completes.
+  auto start = std::chrono::steady_clock::now();
+  while (
+    my_waitable->get_count() <= 1 &&
+    !spin_exited &&
+    (std::chrono::steady_clock::now() - start < 1s))
+  {
+    my_waitable->trigger();
+    this->publisher->publish(test_msgs::msg::Empty());
+    std::this_thread::sleep_for(1ms);
+  }
+
+  EXPECT_EQ(1u, my_waitable->get_count());
+  waitable_interfaces->remove_waitable(my_waitable, nullptr);
+  EXPECT_TRUE(spin_exited);
+  // Cancel if it hasn't exited already.
+  executor.cancel();
+
+  spinner.join();
+}
+
+// Check spin_node_until_future_complete with node base pointer
+TYPED_TEST(TestExecutors, testSpinNodeUntilFutureCompleteNodeBasePtr) {
+  using ExecutorType = TypeParam;
+  ExecutorType executor;
+
+  std::promise<bool> promise;
+  std::future<bool> future = promise.get_future();
+  promise.set_value(true);
+
+  auto shared_future = future.share();
+  auto ret = rclcpp::executors::spin_node_until_future_complete(
+    executor, this->node->get_node_base_interface(), shared_future, 1s);
+  EXPECT_EQ(rclcpp::FutureReturnCode::SUCCESS, ret);
+}
+
+// Check spin_node_until_future_complete with node pointer
+TYPED_TEST(TestExecutors, testSpinNodeUntilFutureCompleteNodePtr) {
+  using ExecutorType = TypeParam;
+  ExecutorType executor;
+
+  std::promise<bool> promise;
+  std::future<bool> future = promise.get_future();
+  promise.set_value(true);
+
+  auto shared_future = future.share();
+  auto ret = rclcpp::executors::spin_node_until_future_complete(
+    executor, this->node, shared_future, 1s);
+  EXPECT_EQ(rclcpp::FutureReturnCode::SUCCESS, ret);
+}
+
 // Check spin_until_future_complete can be properly interrupted.
 TYPED_TEST(TestExecutors, testSpinUntilFutureCompleteInterrupted) {
   using ExecutorType = TypeParam;
@@ -392,186 +576,6 @@ TYPED_TEST(TestExecutors, testSpinUntilFutureCompleteInterrupted) {
   spinner.join();
 }
 
-class TestWaitable : public rclcpp::Waitable
-{
-public:
-  TestWaitable()
-  {
-    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_,
-      rclcpp::contexts::get_global_default_context()->get_rcl_context().get(),
-      guard_condition_options);
-    if (RCL_RET_OK != ret) {
-      rclcpp::exceptions::throw_from_rcl_error(ret);
-    }
-  }
-
-  ~TestWaitable()
-  {
-    rcl_ret_t ret = rcl_guard_condition_fini(&gc_);
-    if (RCL_RET_OK != ret) {
-      fprintf(stderr, "failed to call rcl_guard_condition_fini\n");
-    }
-  }
-
-  bool
-  add_to_wait_set(rcl_wait_set_t * wait_set) override
-  {
-    rcl_ret_t ret = rcl_wait_set_add_guard_condition(wait_set, &gc_, NULL);
-    if (RCL_RET_OK != ret) {
-      return false;
-    }
-    ret = rcl_trigger_guard_condition(&gc_);
-    return RCL_RET_OK == ret;
-  }
-
-  bool
-  is_ready(rcl_wait_set_t * wait_set) override
-  {
-    (void)wait_set;
-    return true;
-  }
-
-  std::shared_ptr<void>
-  take_data() override
-  {
-    return nullptr;
-  }
-
-  void
-  execute(std::shared_ptr<void> & data) override
-  {
-    (void) data;
-    count_++;
-    std::this_thread::sleep_for(1ms);
-  }
-
-  size_t
-  get_number_of_ready_guard_conditions() override {return 1;}
-
-  size_t
-  get_count()
-  {
-    return count_;
-  }
-
-private:
-  size_t count_ = 0;
-  rcl_guard_condition_t gc_;
-};
-
-TYPED_TEST(TestExecutorsStable, spinAll) {
-  using ExecutorType = TypeParam;
-  ExecutorType executor;
-  auto waitable_interfaces = this->node->get_node_waitables_interface();
-  auto my_waitable = std::make_shared<TestWaitable>();
-  waitable_interfaces->add_waitable(my_waitable, nullptr);
-  executor.add_node(this->node);
-
-  // Long timeout, but should not block test if spin_all works as expected as we cancel the
-  // executor.
-  bool spin_exited = false;
-  std::thread spinner([&spin_exited, &executor, this]() {
-      executor.spin_all(1s);
-      executor.remove_node(this->node, true);
-      spin_exited = true;
-    });
-
-  // Do some work until sufficient calls to the waitable occur
-  auto start = std::chrono::steady_clock::now();
-  while (
-    my_waitable->get_count() <= 1 &&
-    !spin_exited &&
-    (std::chrono::steady_clock::now() - start < 1s))
-  {
-    this->publisher->publish(test_msgs::msg::Empty());
-    std::this_thread::sleep_for(1ms);
-  }
-
-  executor.cancel();
-  start = std::chrono::steady_clock::now();
-  while (!spin_exited && (std::chrono::steady_clock::now() - start) < 1s) {
-    std::this_thread::sleep_for(1ms);
-  }
-
-  EXPECT_LT(1u, my_waitable->get_count());
-  waitable_interfaces->remove_waitable(my_waitable, nullptr);
-  ASSERT_TRUE(spin_exited);
-  spinner.join();
-}
-
-TYPED_TEST(TestExecutorsStable, spinSome) {
-  using ExecutorType = TypeParam;
-  ExecutorType executor;
-  auto waitable_interfaces = this->node->get_node_waitables_interface();
-  auto my_waitable = std::make_shared<TestWaitable>();
-  waitable_interfaces->add_waitable(my_waitable, nullptr);
-  executor.add_node(this->node);
-
-  // Long timeout, doesn't block test from finishing because spin_some should exit after the
-  // first one completes.
-  bool spin_exited = false;
-  std::thread spinner([&spin_exited, &executor, this]() {
-      executor.spin_some(1s);
-      executor.remove_node(this->node, true);
-      spin_exited = true;
-    });
-
-  // Do some work until sufficient calls to the waitable occur, but keep going until either
-  // count becomes too large, spin exits, or the 1 second timeout completes.
-  auto start = std::chrono::steady_clock::now();
-  while (
-    my_waitable->get_count() <= 1 &&
-    !spin_exited &&
-    (std::chrono::steady_clock::now() - start < 1s))
-  {
-    this->publisher->publish(test_msgs::msg::Empty());
-    std::this_thread::sleep_for(1ms);
-  }
-
-  EXPECT_EQ(1u, my_waitable->get_count());
-  waitable_interfaces->remove_waitable(my_waitable, nullptr);
-  EXPECT_TRUE(spin_exited);
-  // Cancel if it hasn't exited already.
-  executor.cancel();
-
-  spinner.join();
-}
-
-// Check spin_node_until_future_complete with node base pointer
-TYPED_TEST(TestExecutorsStable, testSpinNodeUntilFutureCompleteNodeBasePtr) {
-  using ExecutorType = TypeParam;
-  ExecutorType executor;
-
-  std::promise<bool> promise;
-  std::future<bool> future = promise.get_future();
-  promise.set_value(true);
-
-  auto shared_future = future.share();
-  auto ret = rclcpp::executors::spin_node_until_future_complete(
-    executor, this->node->get_node_base_interface(), shared_future, 1s);
-  EXPECT_EQ(rclcpp::FutureReturnCode::SUCCESS, ret);
-}
-
-// Check spin_node_until_future_complete with node pointer
-TYPED_TEST(TestExecutorsStable, testSpinNodeUntilFutureCompleteNodePtr) {
-  using ExecutorType = TypeParam;
-  ExecutorType executor;
-
-  std::promise<bool> promise;
-  std::future<bool> future = promise.get_future();
-  promise.set_value(true);
-
-  auto shared_future = future.share();
-  auto ret = rclcpp::executors::spin_node_until_future_complete(
-    executor, this->node, shared_future, 1s);
-  EXPECT_EQ(rclcpp::FutureReturnCode::SUCCESS, ret);
-}
-
 // Check spin_until_future_complete with node base pointer (instantiates its own executor)
 TEST(TestExecutors, testSpinUntilFutureCompleteNodeBasePtr) {
   rclcpp::init(0, nullptr);

rclcpp/test/rclcpp/executors/test_static_executor_entities_collector.cpp

@@ -41,38 +41,38 @@ struct NumberOfEntities
 std::unique_ptr<NumberOfEntities> get_number_of_default_entities(rclcpp::Node::SharedPtr node)
 {
   auto number_of_entities = std::make_unique<NumberOfEntities>();
-  for (auto & weak_group : node->get_callback_groups()) {
-    auto group = weak_group.lock();
-    EXPECT_NE(nullptr, group);
-    if (!group || !group->can_be_taken_from().load()) {
-      return nullptr;
-    }
-    group->find_subscription_ptrs_if(
-      [&number_of_entities](rclcpp::SubscriptionBase::SharedPtr &)
-      {
-        number_of_entities->subscriptions++; return false;
-      });
-    group->find_timer_ptrs_if(
-      [&number_of_entities](rclcpp::TimerBase::SharedPtr &)
-      {
-        number_of_entities->timers++; return false;
-      });
-    group->find_service_ptrs_if(
-      [&number_of_entities](rclcpp::ServiceBase::SharedPtr &)
-      {
-        number_of_entities->services++; return false;
-      });
-    group->find_client_ptrs_if(
-      [&number_of_entities](rclcpp::ClientBase::SharedPtr &)
-      {
-        number_of_entities->clients++; return false;
-      });
-    group->find_waitable_ptrs_if(
-      [&number_of_entities](rclcpp::Waitable::SharedPtr &)
-      {
-        number_of_entities->waitables++; return false;
-      });
-  }
+  node->for_each_callback_group(
+    [&number_of_entities](rclcpp::CallbackGroup::SharedPtr group)
+    {
+      if (!group->can_be_taken_from().load()) {
+        return;
+      }
+      group->find_subscription_ptrs_if(
+        [&number_of_entities](rclcpp::SubscriptionBase::SharedPtr &)
+        {
+          number_of_entities->subscriptions++; return false;
+        });
+      group->find_timer_ptrs_if(
+        [&number_of_entities](rclcpp::TimerBase::SharedPtr &)
+        {
+          number_of_entities->timers++; return false;
+        });
+      group->find_service_ptrs_if(
+        [&number_of_entities](rclcpp::ServiceBase::SharedPtr &)
+        {
+          number_of_entities->services++; return false;
+        });
+      group->find_client_ptrs_if(
+        [&number_of_entities](rclcpp::ClientBase::SharedPtr &)
+        {
+          number_of_entities->clients++; return false;
+        });
+      group->find_waitable_ptrs_if(
+        [&number_of_entities](rclcpp::Waitable::SharedPtr &)
+        {
+          number_of_entities->waitables++; return false;
+        });
+    });
 
   return number_of_entities;
 }
@@ -255,7 +255,7 @@ TEST_F(TestStaticExecutorEntitiesCollector, add_remove_node_with_entities) {
   // Create 1 of each entity type
   auto subscription =
     node->create_subscription<test_msgs::msg::Empty>(
-    "topic", rclcpp::QoS(10), [](test_msgs::msg::Empty::SharedPtr) {});
+    "topic", rclcpp::QoS(10), [](test_msgs::msg::Empty::ConstSharedPtr) {});
   auto timer =
     node->create_wall_timer(std::chrono::seconds(60), []() {});
   auto service =
@@ -267,7 +267,7 @@ TEST_F(TestStaticExecutorEntitiesCollector, add_remove_node_with_entities) {
   auto client = node->create_client<test_msgs::srv::Empty>("service");
   auto waitable = std::make_shared<TestWaitable>();
 
-  // Adding a subscription with rmw_connext_cpp adds another waitable, so we need to get the
+  // Adding a subscription could add another waitable, so we need to get the
   // current number of waitables just before adding the new waitable.
   expected_number_of_entities->waitables = get_number_of_default_entities(node)->waitables;
   node->get_node_waitables_interface()->add_waitable(waitable, nullptr);
@@ -455,7 +455,7 @@ TEST_F(TestStaticExecutorEntitiesCollector, refresh_wait_set_add_handles_to_wait
   // Create 1 of each entity type
   auto subscription =
     node->create_subscription<test_msgs::msg::Empty>(
-    "topic", rclcpp::QoS(10), [](test_msgs::msg::Empty::SharedPtr) {});
+    "topic", rclcpp::QoS(10), [](test_msgs::msg::Empty::ConstSharedPtr) {});
   auto timer =
     node->create_wall_timer(std::chrono::seconds(60), []() {});
   auto service =