WIP

Signed-off-by: Michel Hidalgo <michel@ekumenlabs.com>

rclcpp/include/rclcpp/publisher_options.hpp

@@ -64,8 +64,12 @@ struct PublisherOptionsBase
 template<typename Allocator>
 struct PublisherOptionsWithAllocator : public PublisherOptionsBase
 {
+  static_assert(
+    std::is_void<typename std::allocator_traits<Allocator>::value_type>::value,
+    "Publisher allocator value type must be void");
+
   /// Optional custom allocator.
-  std::shared_ptr<Allocator> allocator = nullptr;
+  mutable std::shared_ptr<Allocator> allocator = nullptr;
 
   PublisherOptionsWithAllocator<Allocator>() {}
 
@@ -80,10 +84,7 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
   to_rcl_publisher_options(const rclcpp::QoS & qos) const
   {
     rcl_publisher_options_t result = rcl_publisher_get_default_options();
-    using AllocatorTraits = std::allocator_traits<Allocator>;
-    using MessageAllocatorT = typename AllocatorTraits::template rebind_alloc<MessageT>;
-    auto message_alloc = std::make_shared<MessageAllocatorT>(*this->get_allocator().get());
-    result.allocator = rclcpp::allocator::get_rcl_allocator<MessageT>(*message_alloc);
+    result.allocator = rclcpp::allocator::get_rcl_allocator<void>(*this->get_allocator());
     result.qos = qos.get_rmw_qos_profile();
     result.rmw_publisher_options.require_unique_network_flow_endpoints =
       this->require_unique_network_flow_endpoints;
@@ -102,7 +103,7 @@ struct PublisherOptionsWithAllocator : public PublisherOptionsBase
   get_allocator() const
   {
     if (!this->allocator) {
-      return std::make_shared<Allocator>();
+      this->allocator = std::make_shared<Allocator>();
     }
     return this->allocator;
   }

rclcpp/include/rclcpp/subscription_options.hpp

@@ -86,8 +86,12 @@ struct SubscriptionOptionsBase
 template<typename Allocator>
 struct SubscriptionOptionsWithAllocator : public SubscriptionOptionsBase
 {
+  static_assert(
+    std::is_void<typename std::allocator_traits<Allocator>::value_type>::value,
+    "Subscription allocator value type must be void");
+
   /// Optional custom allocator.
-  std::shared_ptr<Allocator> allocator = nullptr;
+  mutable std::shared_ptr<Allocator> allocator = nullptr;
 
   SubscriptionOptionsWithAllocator<Allocator>() {}
 
@@ -107,10 +111,7 @@ struct SubscriptionOptionsWithAllocator : public SubscriptionOptionsBase
   to_rcl_subscription_options(const rclcpp::QoS & qos) const
   {
     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>(*this->get_allocator().get());
-    result.allocator = allocator::get_rcl_allocator<MessageT>(*message_alloc);
+    result.allocator = allocator::get_rcl_allocator<void>(*this->get_allocator());
     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 =
@@ -129,7 +130,7 @@ struct SubscriptionOptionsWithAllocator : public SubscriptionOptionsBase
   get_allocator() const
   {
     if (!this->allocator) {
-      return std::make_shared<Allocator>();
+      this->allocator = std::make_shared<Allocator>();
     }
     return this->allocator;
   }