Fix component lifecycle (#1098)

* Correctly reset async_thread_shutdown when starting the async thread

* Do not use a global log handler object

---------

Author: Felix Exner (fexner)

ur_robot_driver/include/ur_robot_driver/hardware_interface.hpp

@@ -191,7 +191,7 @@ class URPositionHardwareInterface : public hardware_interface::SystemInterface
   bool first_pass_;
   bool initialized_;
   double system_interface_initialized_;
-  bool async_thread_shutdown_;
+  std::atomic_bool async_thread_shutdown_;
   double get_robot_software_version_major_;
   double get_robot_software_version_minor_;
   double get_robot_software_version_bugfix_;

ur_robot_driver/src/hardware_interface.cpp

@@ -534,6 +534,7 @@ void URPositionHardwareInterface::readBitsetData(const std::unique_ptr<rtde::Dat
 
 void URPositionHardwareInterface::asyncThread()
 {
+  async_thread_shutdown_ = false;
   while (!async_thread_shutdown_) {
     if (initialized_) {
       //        RCLCPP_INFO(rclcpp::get_logger("URPositionHardwareInterface"), "Initialized in async thread");

ur_robot_driver/src/urcl_log_handler.cpp

@@ -49,7 +49,6 @@
 namespace ur_robot_driver
 {
 bool g_registered = false;
-std::unique_ptr<UrclLogHandler> g_log_handler(new UrclLogHandler);
 
 UrclLogHandler::UrclLogHandler() = default;
 
@@ -82,10 +81,11 @@ void UrclLogHandler::log(const char* file, int line, urcl::LogLevel loglevel, co
 void registerUrclLogHandler(const std::string& tf_prefix)
 {
   if (g_registered == false) {
-    g_log_handler->setTFPrefix(tf_prefix);
+    std::unique_ptr<UrclLogHandler> log_handler(new UrclLogHandler);
+    log_handler->setTFPrefix(tf_prefix);
     // Log level is decided by ROS2 log level
     urcl::setLogLevel(urcl::LogLevel::DEBUG);
-    urcl::registerLogHandler(std::move(g_log_handler));
+    urcl::registerLogHandler(std::move(log_handler));
     g_registered = true;
   }
 }