modernize to cpp20 (#358)

Signed-off-by: Alejandro Hernandez Cordero <ahcorde@gmail.com>

Author: ahcorde

rqt_gui_cpp/CMakeLists.txt

@@ -2,18 +2,16 @@ cmake_minimum_required(VERSION 3.20)
 project(rqt_gui_cpp)
 
 find_package(ament_cmake REQUIRED)
+find_package(ament_cmake_ros_core REQUIRED)
 
 if(WIN32)
   message(STATUS "rqt_gui_cpp is not yet supported on Windows. Package will not be built.")
   ament_package()
   return()
 endif()
 
-# Default to C++17
-if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 17)
-  set(CMAKE_CXX_STANDARD_REQUIRED ON)
-endif()
+# The C++ standard (C++20) is provided by the
+# ament_cmake_ros_core::ament_ros_defaults interface target linked below.
 
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic -fPIC)
@@ -59,6 +57,7 @@ target_link_libraries(${PROJECT_NAME} PUBLIC
 )
 
 target_link_libraries(${PROJECT_NAME} PRIVATE
+  ament_cmake_ros_core::ament_ros_defaults
   pluginlib::pluginlib
   Qt${QT_VERSION_MAJOR}::Widgets
 )

rqt_gui_cpp/include/rqt_gui_cpp/plugin.hpp

@@ -52,15 +52,13 @@ class Plugin
   : public qt_gui_cpp::Plugin
 {
 public:
-  Plugin()
-  : qt_gui_cpp::Plugin()
-  {}
+  Plugin() = default;
 
   /**
    * Shutdown and clean up the plugin before unloading.
    * I.e. unregister subscribers and stop timers.
    */
-  virtual void shutdownPlugin()
+  void shutdownPlugin() override
   {}
 
   virtual void passInNode(std::shared_ptr<rclcpp::Node> node)

rqt_gui_cpp/package.xml

@@ -14,6 +14,7 @@
   <author email="michael.jeronimo@openrobotics.org">Michael Jeronimo</author>
 
   <buildtool_depend>ament_cmake</buildtool_depend>
+  <buildtool_depend>ament_cmake_ros_core</buildtool_depend>
 
   <depend>pluginlib</depend>
   <depend>rclcpp</depend>

rqt_gui_cpp/src/rqt_gui_cpp/nodelet_plugin_provider.cpp

@@ -33,6 +33,7 @@
 #include "nodelet_plugin_provider.hpp"
 
 #include <unistd.h>
+#include <format>
 #include <memory>
 #include <stdexcept>
 #include <string>
@@ -46,17 +47,17 @@ NodeletPluginProvider::NodeletPluginProvider(
   const QString & base_class_type)
 : qt_gui_cpp::RosPluginlibPluginProvider<rqt_gui_cpp::Plugin>(export_tag, base_class_type)
   , loader_initialized_(false)
-  , ros_spin_thread_(0)
+  , ros_spin_thread_(nullptr)
 {}
 
 NodeletPluginProvider::~NodeletPluginProvider()
 {
-  if (ros_spin_thread_ != 0) {
+  if (ros_spin_thread_ != nullptr) {
     ros_spin_thread_->abort = true;
     ros_spin_thread_->exec_.remove_node(node_);
     ros_spin_thread_->wait();
     ros_spin_thread_->deleteLater();
-    ros_spin_thread_ = 0;
+    ros_spin_thread_ = nullptr;
   }
 }
 
@@ -76,16 +77,13 @@ void NodeletPluginProvider::init_loader()
     loader_initialized_ = true;
 
     // spawn ros spin thread
-    if (ros_spin_thread_ == 0) {
+    if (ros_spin_thread_ == nullptr) {
       ros_spin_thread_ = new RosSpinThread(this);
       ros_spin_thread_->start();
     }
 
-    std::stringstream name;
-    name << "rqt_gui_cpp_node_";
-    name << getpid();
     // Initialize a node for execution to be shared by cpp plugins
-    node_ = rclcpp::Node::make_shared(name.str().c_str());
+    node_ = rclcpp::Node::make_shared(std::format("rqt_gui_cpp_node_{}", getpid()));
     // Add our node to the executor for execution
     if (ros_spin_thread_) {
       ros_spin_thread_->exec_.add_node(node_);
@@ -101,8 +99,7 @@ std::shared_ptr<Plugin> NodeletPluginProvider::create_plugin(
 {
   init_loader();
 
-  std::string nodelet_name = lookup_name + "_" +
-    QString::number(plugin_context->serialNumber()).toStdString();
+  std::string nodelet_name = std::format("{}_{}", lookup_name, plugin_context->serialNumber());
   instance_.reset();
 
   instance_ =
@@ -137,8 +134,7 @@ NodeletPluginProvider::RosSpinThread::RosSpinThread(QObject * parent)
   , abort(false)
 {}
 
-NodeletPluginProvider::RosSpinThread::~RosSpinThread()
-{}
+NodeletPluginProvider::RosSpinThread::~RosSpinThread() = default;
 
 void NodeletPluginProvider::RosSpinThread::run()
 {

rqt_gui_cpp/src/rqt_gui_cpp/nodelet_plugin_provider.hpp

@@ -53,20 +53,20 @@ class NodeletPluginProvider
 public:
   NodeletPluginProvider(const QString & export_tag, const QString & base_class_type);
 
-  virtual ~NodeletPluginProvider();
+  ~NodeletPluginProvider() override;
 
-  virtual void unload(void * instance);
+  void unload(void * instance) override;
 
 protected:
   void init_loader();
 
-  virtual std::shared_ptr<Plugin> create_plugin(
+  std::shared_ptr<Plugin> create_plugin(
     const std::string & lookup_name,
-    qt_gui_cpp::PluginContext * plugin_context);
+    qt_gui_cpp::PluginContext * plugin_context) override;
 
-  virtual void init_plugin(
+  void init_plugin(
     const QString & plugin_id, qt_gui_cpp::PluginContext * plugin_context,
-    qt_gui_cpp::Plugin * plugin);
+    qt_gui_cpp::Plugin * plugin) override;
 
   std::shared_ptr<rqt_gui_cpp::Plugin> instance_;
 
@@ -82,9 +82,9 @@ class NodeletPluginProvider
     : public QThread
   {
 public:
-    explicit RosSpinThread(QObject * parent = 0);
-    virtual ~RosSpinThread();
-    void run();
+    explicit RosSpinThread(QObject * parent = nullptr);
+    ~RosSpinThread() override;
+    void run() override;
     bool abort;
     // Create an executor that will be responsible for execution of callbacks for a set of nodes.
     // With this version, all callbacks will be called from within this thread (the main one).

rqt_gui_cpp/src/rqt_gui_cpp/roscpp_plugin_provider.cpp

@@ -86,7 +86,7 @@ void RosCppPluginProvider::init_rclcpp()
   // initialize ROS node once
   if (!rclcpp_initialized_) {
     int argc = 0;
-    char ** argv = 0;
+    char ** argv = nullptr;
 
     // Initialize any global resources needed by the middleware and the client library.
     // This will also parse command line arguments one day (as of Beta 1 they are not used).

rqt_gui_cpp/src/rqt_gui_cpp/roscpp_plugin_provider.hpp

@@ -46,13 +46,13 @@ class RosCppPluginProvider
 public:
   RosCppPluginProvider();
 
-  virtual ~RosCppPluginProvider();
+  ~RosCppPluginProvider() override;
 
-  virtual void * load(const QString & plugin_id, qt_gui_cpp::PluginContext * plugin_context);
+  void * load(const QString & plugin_id, qt_gui_cpp::PluginContext * plugin_context) override;
 
-  virtual qt_gui_cpp::Plugin * load_plugin(
+  qt_gui_cpp::Plugin * load_plugin(
     const QString & plugin_id,
-    qt_gui_cpp::PluginContext * plugin_context);
+    qt_gui_cpp::PluginContext * plugin_context) override;
 
 protected:
   void init_rclcpp();