Add action typesupport helper

Signed-off-by: Barry Xu <[email protected]>

rclcpp/include/rclcpp/typesupport_helpers.hpp

@@ -23,6 +23,7 @@
 #include "rcpputils/shared_library.hpp"
 #include "rosidl_runtime_cpp/message_type_support_decl.hpp"
 #include "rosidl_runtime_cpp/service_type_support_decl.hpp"
+#include "rosidl_runtime_cpp/action_type_support_decl.hpp"
 
 #include "rclcpp/visibility_control.hpp"
 
@@ -76,7 +77,7 @@ get_message_typesupport_handle(
 
 /// Extract the service 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.
+ * The library needs to match the service type. The shared library must stay loaded for the lifetime of the result.
  *
  * \param[in] type The service type, e.g. "std_srvs/srv/Empty"
  * \param[in] typesupport_identifier Type support identifier, typically "rosidl_typesupport_cpp"
@@ -91,6 +92,23 @@ get_service_typesupport_handle(
   const std::string & typesupport_identifier,
   rcpputils::SharedLibrary & library);
 
+/// Extract the action type support handle from the library.
+/**
+ * The library needs to match the action type. The shared library must stay loaded for the lifetime of the result.
+ *
+ * \param[in] type The action type, e.g. "action_tutorials_interfaces/action/Fibonacci"
+ * \param[in] typesupport_identifier Type support identifier, typically "rosidl_typesupport_cpp"
+ * \param[in] library The shared type support library
+ * \throws std::runtime_error if the symbol of type not found in the library.
+ * \return A action type support handle
+ */
+RCLCPP_PUBLIC
+const rosidl_action_type_support_t *
+get_action_typesupport_handle(
+  const std::string & type,
+  const std::string & typesupport_identifier,
+  rcpputils::SharedLibrary & library);
+
 }  // namespace rclcpp
 
 #endif  // RCLCPP__TYPESUPPORT_HELPERS_HPP_

rclcpp/src/rclcpp/typesupport_helpers.cpp

@@ -177,4 +177,19 @@ const rosidl_service_type_support_t * get_service_typesupport_handle(
   ));
 }
 
+const rosidl_action_type_support_t * get_action_typesupport_handle(
+  const std::string & type,
+  const std::string & typesupport_identifier,
+  rcpputils::SharedLibrary & library)
+{
+  static const std::string typesupport_name = "action";
+  static const std::string symbol_part_name = "__get_action_type_support_handle__";
+  static const std::string middle_module_additional = "action";
+
+  return static_cast<const rosidl_action_type_support_t *>(get_typesupport_handle_impl(
+           type, typesupport_identifier, typesupport_name, symbol_part_name,
+           middle_module_additional, library
+  ));
+}
+
 }  // namespace rclcpp