Support action typesupport helper

rclcpp/include/rclcpp/typesupport_helpers.hpp

@@ -21,6 +21,7 @@
 #include <tuple>
 
 #include "rcpputils/shared_library.hpp"
+#include "rosidl_runtime_cpp/action_type_support_decl.hpp"
 #include "rosidl_runtime_cpp/message_type_support_decl.hpp"
 #include "rosidl_runtime_cpp/service_type_support_decl.hpp"
 
@@ -72,6 +73,24 @@ 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. "example_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

rclcpp/test/rclcpp/test_typesupport_helpers.cpp

@@ -106,21 +106,55 @@ TEST(TypesupportHelpersTest, returns_service_type_info_for_valid_library) {
   }
 }
 
+TEST(TypesupportHelpersTest, returns_action_type_info_for_valid_legacy_library) {
+  try {
+    auto library = rclcpp::get_typesupport_library(
+      "test_msgs/NestedMessage", "rosidl_typesupport_cpp");
+    auto nestedmessage_typesupport = rclcpp::get_action_typesupport_handle(
+      "test_msgs/NestedMessage", "rosidl_typesupport_cpp", *library);
+
+    EXPECT_THAT(
+      std::string(nestedmessage_typesupport->goal_service_type_support->typesupport_identifier),
+      ContainsRegex("rosidl_typesupport"));
+  } catch (const std::runtime_error & e) {
+    FAIL() << e.what();
+  }
+}
+
+TEST(TypesupportHelpersTest, returns_action_type_info_for_valid_library) {
+  try {
+    auto library = rclcpp::get_typesupport_library(
+      "test_msgs/action/NestedMessage", "rosidl_typesupport_cpp");
+    auto nestedmessage_typesupport = rclcpp::get_action_typesupport_handle(
+      "test_msgs/action/NestedMessage", "rosidl_typesupport_cpp", *library);
+
+    EXPECT_THAT(
+      std::string(nestedmessage_typesupport->goal_service_type_support->typesupport_identifier),
+      ContainsRegex("rosidl_typesupport"));
+  } catch (const std::runtime_error & e) {
+    FAIL() << e.what();
+  }
+}
+
 TEST(TypesupportHelpersTest, test_throw_exception_with_invalid_type) {
   // message
   std::string invalid_type = "test_msgs/msg/InvalidType";
   auto library = rclcpp::get_typesupport_library(invalid_type, "rosidl_typesupport_cpp");
   EXPECT_THROW(
     rclcpp::get_message_typesupport_handle(invalid_type, "rosidl_typesupport_cpp", *library),
     std::runtime_error);
-  EXPECT_THROW(
-    rclcpp::get_service_typesupport_handle(invalid_type, "rosidl_typesupport_cpp", *library),
-    std::runtime_error);
 
   // service
   invalid_type = "test_msgs/srv/InvalidType";
   library = rclcpp::get_typesupport_library(invalid_type, "rosidl_typesupport_cpp");
   EXPECT_THROW(
     rclcpp::get_service_typesupport_handle(invalid_type, "rosidl_typesupport_cpp", *library),
     std::runtime_error);
+
+  // action
+  invalid_type = "test_msgs/action/InvalidType";
+  library = rclcpp::get_typesupport_library(invalid_type, "rosidl_typesupport_cpp");
+  EXPECT_THROW(
+    rclcpp::get_action_typesupport_handle(invalid_type, "rosidl_typesupport_cpp", *library),
+    std::runtime_error);
 }