Cmake infrastructure for creating components

rclcpp_components/CMakeLists.txt

@@ -41,6 +41,11 @@ ament_target_dependencies(component_container
   "rclcpp"
 )
 
+install(FILES 
+  src/node_main.cpp.in
+  DESTINATION ${PROJECT_BINARY_DIR}
+)
+
 add_executable(
   component_container_mt
   src/component_container_mt.cpp

rclcpp_components/cmake/rclcpp_components_register_node.cmake

@@ -0,0 +1,69 @@
+# 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.
+#
+# usage: rclcpp_components_register_node(
+#              <target> PLUGIN <component> EXECUTABLE <node>)
+#
+# Register an rclcpp component with the ament
+# resource index and create an executable.
+#
+# :param target: the shared library target
+# :type target: string
+# :param ARGS: the plugin name and node name for executable
+# :type ARGS: list of strings
+# :param component: the component plugin name
+# :type component: string
+# :param node: the node's executable name
+# :type node: string
+#
+macro(rclcpp_components_register_node target)
+  cmake_parse_arguments(
+    ARGS
+    ""
+    "PLUGIN;EXECUTABLE"
+    ""
+    ${ARGN})
+  set(component ${ARGS_PLUGIN})
+  set(node ${ARGS_EXECUTABLE})
+  _rclcpp_components_register_package_hook()
+  if(WIN32)
+    set(_path "bin")
+  else()
+    set(_path "lib")
+  endif()
+  set(_RCLCPP_COMPONENTS__NODES
+    "${_RCLCPP_COMPONENTS__NODES}${component};${_path}/$<TARGET_FILE_NAME:${target}>\n")
+  set(CLASS_NAME ${component})
+  set(build_dir ${PROJECT_BINARY_DIR}/../rclcpp_components) 
+  configure_file(${build_dir}/node_main.cpp.in
+    ${build_dir}/node_main_${node}.cpp @ONLY)
+  add_executable(${node} ${build_dir}/node_main_${node}.cpp)
+  set(lib ${target})
+  # Needed so symbols aren't dropped if not usesd
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    set(lib
+      "-Wl,--no-as-needed"
+      ${target}
+      "-Wl,--as-needed")
+  endif()
+  target_link_libraries(${node}
+    ${lib})
+  ament_target_dependencies(${node}
+    "rclcpp"
+    "class_loader"
+    "rclcpp_components")
+  install(TARGETS
+    ${node}
+    DESTINATION lib/${PROJECT_NAME})
+endmacro()

rclcpp_components/rclcpp_components-extras.cmake

@@ -26,4 +26,4 @@ macro(_rclcpp_components_register_package_hook)
 endmacro()
 
 include("${rclcpp_components_DIR}/rclcpp_components_register_nodes.cmake")
-
+include("${rclcpp_components_DIR}/rclcpp_components_register_node.cmake")

rclcpp_components/src/node_main.cpp.in

@@ -0,0 +1,70 @@
+// Copyright 2016 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.
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "class_loader/class_loader.hpp"
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp_components/node_factory.hpp"
+#include "rclcpp_components/node_factory_template.hpp"
+
+#define NODE_MAIN_LOGGER_NAME "node_main"
+
+int main(int argc, char * argv[])
+{
+  // Force flush of the stdout buffer.
+  setvbuf(stdout, NULL, _IONBF, BUFSIZ);
+
+  auto args = rclcpp::init_and_remove_ros_arguments(argc, argv);
+  rclcpp::Logger logger = rclcpp::get_logger(NODE_MAIN_LOGGER_NAME);
+  rclcpp::executors::SingleThreadedExecutor exec;
+  rclcpp::NodeOptions options;
+  options.arguments(args);
+  std::vector<class_loader::ClassLoader *> loaders;
+  std::vector<rclcpp_components::NodeInstanceWrapper> node_wrappers;
+  std::vector<std::string> libraries = {
+    // all classes from libraries linked by the linker (rather then dlopen)
+    // are registered under the library_path ""
+    "",
+  };
+  std::string className = "rclcpp_components::NodeFactoryTemplate<@CLASS_NAME@>";
+  for (const auto & library : libraries) {
+    RCLCPP_DEBUG(logger, "Loading library %s", library.c_str());
+    auto loader = new class_loader::ClassLoader(library);
+    auto classes = loader->getAvailableClasses<rclcpp_components::NodeFactory>();
+    for (auto clazz : classes) {
+      std::string name = clazz.c_str();
+      if (!(name.compare(className))) {
+        RCLCPP_DEBUG(logger, "Instantiate class %s", clazz.c_str());
+        auto node_factory = loader->createInstance<rclcpp_components::NodeFactory>(clazz);
+        auto wrapper = node_factory->create_node_instance(options);
+        auto node = wrapper.get_node_base_interface();
+        node_wrappers.push_back(wrapper);
+        exec.add_node(node);
+      }
+    }
+    loaders.push_back(loader);
+  }
+
+  exec.spin();
+
+  for (auto wrapper : node_wrappers) {
+    exec.remove_node(wrapper.get_node_base_interface());
+  }
+  node_wrappers.clear();
+  rclcpp::shutdown();
+  return 0;
+}