Introduce rclcpp_components to implement composition

rclcpp/CMakeLists.txt

@@ -432,14 +432,7 @@ if(BUILD_TESTING)
   endif()
 endif()
 
-ament_package(
-  CONFIG_EXTRAS rclcpp-extras.cmake
-)
-
-install(
-  DIRECTORY cmake
-  DESTINATION share/${PROJECT_NAME}
-)
+ament_package()
 
 install(
   DIRECTORY include/ ${CMAKE_CURRENT_BINARY_DIR}/include/

rclcpp_components/CMakeLists.txt

@@ -0,0 +1,82 @@
+cmake_minimum_required(VERSION 3.5)
+
+project(rclcpp_components)
+
+# Default to C++14
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 14)
+endif()
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+find_package(ament_cmake_ros REQUIRED)
+find_package(ament_index_cpp REQUIRED)
+find_package(class_loader REQUIRED)
+find_package(composition_interfaces REQUIRED)
+find_package(rclcpp REQUIRED)
+find_package(rcpputils REQUIRED)
+
+include_directories(include)
+
+add_executable(
+  component_container
+  src/component_container.cpp
+  src/component_manager.cpp
+)
+
+ament_target_dependencies(component_container
+  "ament_index_cpp"
+  "class_loader"
+  "composition_interfaces"
+  "rclcpp"
+  "rcpputils"
+)
+
+add_executable(
+  component_container_mt
+  src/component_container_mt.cpp
+  src/component_manager.cpp
+)
+
+ament_target_dependencies(component_container_mt
+  "ament_index_cpp"
+  "class_loader"
+  "composition_interfaces"
+  "rclcpp"
+  "rcpputils"
+)
+
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+  target_link_libraries(component_container "stdc++fs")
+  target_link_libraries(component_container_mt "stdc++fs")
+endif()
+
+if(BUILD_TESTING)
+  find_package(ament_lint_auto REQUIRED)
+  ament_lint_auto_find_test_dependencies()
+endif()
+
+# Install executables
+install(
+  TARGETS component_container component_container_mt
+  RUNTIME DESTINATION lib/${PROJECT_NAME}
+)
+
+# Install include directories
+install(
+  DIRECTORY include/
+  DESTINATION include
+)
+
+# Install cmake
+install(
+  DIRECTORY cmake
+  DESTINATION share/${PROJECT_NAME}
+)
+
+# specific order: dependents before dependencies
+ament_export_include_directories(include)
+ament_export_dependencies(class_loader)
+ament_export_dependencies(rclcpp)
+ament_package(CONFIG_EXTRAS rclcpp_components-extras.cmake)

rclcpp/cmake/rclcpp_package_hook.cmake → rclcpp_components/cmake/rclcpp_components_package_hook.cmake

@@ -1,4 +1,4 @@
-# Copyright 2016 Open Source Robotics Foundation, Inc.
+# Copyright 2019 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.
@@ -14,4 +14,5 @@
 
 # register node plugins
 ament_index_register_resource(
-  "node_plugin" CONTENT "${_RCLCPP__NODE_PLUGINS}")
+  "rclcpp_components" CONTENT "${_RCLCPP_COMPONENTS__NODES}")
+

rclcpp/cmake/rclcpp_register_node_plugins.cmake → rclcpp_components/cmake/rclcpp_components_register_nodes.cmake

@@ -1,4 +1,4 @@
-# Copyright 2016 Open Source Robotics Foundation, Inc.
+# Copyright 2019 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.
@@ -13,38 +13,38 @@
 # limitations under the License.
 
 #
-# Register a node plugin with the ament resource index.
+# Register an rclcpp component with the ament resource index.
 #
-# The passed library can contain multiple plugins extending the node interface.
+# The passed library can contain multiple nodes each registered via macro.
 #
 # :param target: the shared library target
 # :type target: string
 # :param ARGN: the unique plugin names being exported using class_loader
 # :type ARGN: list of strings
 #
-macro(rclcpp_register_node_plugins target)
+macro(rclcpp_components_register_nodes target)
   if(NOT TARGET ${target})
     message(
       FATAL_ERROR
-      "rclcpp_register_node_plugins() first argument "
+      "rclcpp_components_register_nodes() first argument "
       "'${target}' is not a target")
   endif()
   get_target_property(_target_type ${target} TYPE)
   if(NOT _target_type STREQUAL "SHARED_LIBRARY")
     message(
       FATAL_ERROR
-      "rclcpp_register_node_plugins() first argument "
+      "rclcpp_components_register_nodes() first argument "
       "'${target}' is not a shared library target")
   endif()
 
   if(${ARGC} GREATER 0)
-    _rclcpp_register_package_hook()
+    _rclcpp_components_register_package_hook()
     set(_unique_names)
     foreach(_arg ${ARGN})
       if(_arg IN_LIST _unique_names)
         message(
           FATAL_ERROR
-          "rclcpp_register_node_plugins() the plugin names "
+          "rclcpp_components_register_nodes() the plugin names "
           "must be unique (multiple '${_arg}')")
       endif()
       list(APPEND _unique_names "${_arg}")
@@ -54,8 +54,9 @@ macro(rclcpp_register_node_plugins target)
       else()
         set(_path "lib")
       endif()
-      set(_RCLCPP__NODE_PLUGINS
-        "${_RCLCPP__NODE_PLUGINS}${_arg};${_path}/$<TARGET_FILE_NAME:${target}>\n")
+      set(_RCLCPP_COMPONENTS__NODES
+        "${_RCLCPP_COMPONENTS__NODES}${_arg};${_path}/$<TARGET_FILE_NAME:${target}>\n")
     endforeach()
   endif()
 endmacro()
+

rclcpp_components/include/rclcpp_components/node_factory.hpp

@@ -0,0 +1,46 @@
+// Copyright 2019 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_COMPONENTS__NODE_FACTORY_HPP__
+#define RCLCPP_COMPONENTS__NODE_FACTORY_HPP__
+
+#include "rclcpp_components/node_instance_wrapper.hpp"
+
+namespace rclcpp_components
+{
+
+/// The NodeFactory interface is used by the class loader to instantiate components.
+/**
+ * The NodeFactory interface serves two purposes:
+ *  * It allows for classes not derived from `rclcpp::Node` to be used as components.
+ *  * It derived constructors to be called when components are loaded.
+ */
+class NodeFactory
+{
+public:
+  NodeFactory() = default;
+
+  virtual ~NodeFactory() = default;
+
+  /// Create an instance of a component
+  /**
+   * \param[in] options Additional options used in the construction of the component.
+   */
+  virtual
+  NodeInstanceWrapper
+  create_node_instance(const rclcpp::NodeOptions & options) = 0;
+};
+}  // namespace rclcpp_components
+
+#endif  // RCLCPP_COMPONENTS__NODE_FACTORY_HPP__

rclcpp_components/include/rclcpp_components/node_factory_template.hpp

@@ -0,0 +1,54 @@
+// Copyright 2019 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_COMPONENTS__NODE_FACTORY_TEMPLATE_HPP__
+#define RCLCPP_COMPONENTS__NODE_FACTORY_TEMPLATE_HPP__
+
+#include <functional>
+#include <memory>
+
+#include "rclcpp_components/node_factory.hpp"
+
+namespace rclcpp_components
+{
+
+/// NodeFactoryTemplate is a convenience class for instantiating components.
+/**
+ * The NodeFactoryTemplate class can be used to easily proved the NodeFactory interface for
+ * components that implement a single-argument constructor and `get_node_base_interface`.
+ */
+template<typename NodeT>
+class NodeFactoryTemplate : public NodeFactory
+{
+public:
+  NodeFactoryTemplate() = default;
+  virtual ~NodeFactoryTemplate() = default;
+
+  /// Create an instance of a component
+  /**
+   * \param[in] options Additional options used in the construction of the component.
+   */
+  virtual
+  NodeInstanceWrapper
+  create_node_instance(const rclcpp::NodeOptions & options)
+  {
+    auto node = std::make_shared<NodeT>(options);
+
+    return NodeInstanceWrapper(
+      node, std::bind(&NodeT::get_node_base_interface, node));
+  }
+};
+}  // namespace rclcpp_components
+
+#endif  // RCLCPP_COMPONENTS__NODE_FACTORY_TEMPLATE_HPP__

rclcpp_components/include/rclcpp_components/node_instance_wrapper.hpp

@@ -0,0 +1,70 @@
+// Copyright 2019 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_COMPONENTS__NODE_INSTANCE_WRAPPER_HPP__
+#define RCLCPP_COMPONENTS__NODE_INSTANCE_WRAPPER_HPP__
+
+#include <functional>
+#include <memory>
+
+#include "rclcpp/node_interfaces/node_base_interface.hpp"
+
+namespace rclcpp_components
+{
+/// The NodeInstanceWrapper encapsulates the node instance.
+class NodeInstanceWrapper
+{
+public:
+  using NodeBaseInterfaceGetter = std::function<
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr(const std::shared_ptr<void> &)>;
+
+  NodeInstanceWrapper()
+  : node_instance_(nullptr)
+  {}
+
+  NodeInstanceWrapper(
+    std::shared_ptr<void> node_instance,
+    NodeBaseInterfaceGetter node_base_interface_getter)
+  : node_instance_(node_instance), node_base_interface_getter_(node_base_interface_getter)
+  {}
+
+  /// Get a type-erased pointer to the original Node instance
+  /**
+   * This is only for debugging and special cases.
+   * For most cases `get_node_base_interface` will be sufficient
+   * \return Shared pointer to the encapsulated Node instance.
+   */
+  const std::shared_ptr<void>
+  get_node_instance() const
+  {
+    return node_instance_;
+  }
+
+  /// Get NodeBaseInterface pointer for the encapsulated Node Instance.
+  /**
+   * \return Shared NodeBaseInterface pointer of the encapsulated Node instance.
+   */
+  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr
+  get_node_base_interface()
+  {
+    return node_base_interface_getter_(node_instance_);
+  }
+
+private:
+  std::shared_ptr<void> node_instance_;
+  NodeBaseInterfaceGetter node_base_interface_getter_;
+};
+}  // namespace rclcpp_components
+
+#endif  // RCLCPP_COMPONENTS__NODE_INSTANCE_WRAPPER_HPP__