Implement dynamic subscription and C++ wrapper classes

Signed-off-by: methylDragon <[email protected]>

rclcpp/CMakeLists.txt

@@ -105,6 +105,7 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/qos.cpp
   src/rclcpp/event_handler.cpp
   src/rclcpp/qos_overriding_options.cpp
+  src/rclcpp/dynamic_subscription.cpp
   src/rclcpp/serialization.cpp
   src/rclcpp/serialized_message.cpp
   src/rclcpp/service.cpp

rclcpp/include/rclcpp/dynamic_subscription.hpp

@@ -0,0 +1,175 @@
+// Copyright 2022 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__DYNAMIC_SUBSCRIPTION_HPP_
+#define RCLCPP__DYNAMIC_SUBSCRIPTION_HPP_
+
+#include <rosidl_dynamic_typesupport/identifier.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "rcpputils/shared_library.hpp"
+
+#include "rclcpp/callback_group.hpp"
+#include "rclcpp/dynamic_typesupport/dynamic_message_type_support.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 messages whose type descriptions are obtained at runtime.
+/**
+ * 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.
+ *
+ * NOTE(methylDragon): No considerations for intra-process handling are made.
+ */
+class DynamicSubscription : public rclcpp::SubscriptionBase
+{
+public:
+  // cppcheck-suppress unknownMacro
+  RCLCPP_SMART_PTR_DEFINITIONS(DynamicSubscription)
+
+  template<typename AllocatorT = std::allocator<void>>
+  DynamicSubscription(
+    rclcpp::node_interfaces::NodeBaseInterface * node_base,
+    rclcpp::dynamic_typesupport::DynamicMessageTypeSupport::SharedPtr type_support,
+    const std::string & topic_name,
+    const rclcpp::QoS & qos,
+    std::function<void(
+      rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr,
+      const rosidl_runtime_c__type_description__TypeDescription &
+    )> callback,
+    const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options)
+  : SubscriptionBase(
+      node_base,
+      type_support->get_const_rosidl_message_type_support(),
+      topic_name,
+      options.to_rcl_subscription_options(
+        qos),
+      options.event_callbacks,
+      options.use_default_callbacks,
+      DeliveredMessageKind::DYNAMIC_MESSAGE),
+    ts_(type_support),
+    callback_(callback),
+    serialization_support_(nullptr),
+    dynamic_message_(nullptr),
+    dynamic_message_type_(nullptr)
+  {
+    if (!type_support) {
+      throw std::runtime_error("DynamicMessageTypeSupport cannot be nullptr!");
+    }
+
+    if (type_support->get_const_rosidl_message_type_support().typesupport_identifier !=
+      rosidl_get_dynamic_typesupport_identifier())
+    {
+      throw std::runtime_error(
+              "DynamicSubscription must use dynamic type introspection type support!");
+    }
+
+    serialization_support_ = type_support->get_shared_dynamic_serialization_support();
+    dynamic_message_type_ = type_support->get_shared_dynamic_message_type()->clone_shared();
+    dynamic_message_ = type_support->get_shared_dynamic_message()->clone_shared();
+  }
+
+  // TODO(methylDragon):
+  /// Deferred type description constructor, only usable if the middleware implementation supports
+  /// type discovery
+
+  RCLCPP_PUBLIC
+  virtual ~DynamicSubscription() = default;
+
+  // Same as create_serialized_message() as the subscription is to serialized_messages only
+  RCLCPP_PUBLIC
+  std::shared_ptr<void> create_message() override;
+
+  RCLCPP_PUBLIC
+  std::shared_ptr<rclcpp::SerializedMessage> create_serialized_message() override;
+
+  /// Cast the message to a rclcpp::SerializedMessage and call the callback.
+  RCLCPP_PUBLIC
+  void handle_message(
+    std::shared_ptr<void> & message, const rclcpp::MessageInfo & message_info) override;
+
+  /// Handle dispatching rclcpp::SerializedMessage to user callback.
+  RCLCPP_PUBLIC
+  void
+  handle_serialized_message(
+    const std::shared_ptr<rclcpp::SerializedMessage> & serialized_message,
+    const rclcpp::MessageInfo & message_info) override;
+
+  /// This function is currently not implemented.
+  RCLCPP_PUBLIC
+  void handle_loaned_message(
+    void * loaned_message, const rclcpp::MessageInfo & message_info) override;
+
+  // Same as return_serialized_message() as the subscription is to serialized_messages only
+  RCLCPP_PUBLIC
+  void return_message(std::shared_ptr<void> & message) override;
+
+  RCLCPP_PUBLIC
+  void return_serialized_message(std::shared_ptr<rclcpp::SerializedMessage> & message) override;
+
+
+  // DYNAMIC TYPE ==================================================================================
+  // TODO(methylDragon): Reorder later
+  RCLCPP_PUBLIC
+  rclcpp::dynamic_typesupport::DynamicMessageType::SharedPtr
+  get_shared_dynamic_message_type() override;
+
+  RCLCPP_PUBLIC
+  rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr get_shared_dynamic_message() override;
+
+  RCLCPP_PUBLIC
+  rclcpp::dynamic_typesupport::DynamicSerializationSupport::SharedPtr
+  get_shared_dynamic_serialization_support() override;
+
+  RCLCPP_PUBLIC
+  rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr create_dynamic_message() override;
+
+  RCLCPP_PUBLIC
+  void return_dynamic_message(
+    rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message) override;
+
+  RCLCPP_PUBLIC
+  void handle_dynamic_message(
+    const rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message,
+    const rclcpp::MessageInfo & message_info) override;
+
+private:
+  RCLCPP_DISABLE_COPY(DynamicSubscription)
+
+  rclcpp::dynamic_typesupport::DynamicMessageTypeSupport::SharedPtr ts_;
+  std::function<void(
+      rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr,
+      const rosidl_runtime_c__type_description__TypeDescription &
+    )> callback_;
+
+  rclcpp::dynamic_typesupport::DynamicSerializationSupport::SharedPtr serialization_support_;
+  rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr dynamic_message_;
+  rclcpp::dynamic_typesupport::DynamicMessageType::SharedPtr dynamic_message_type_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__DYNAMIC_SUBSCRIPTION_HPP_