fix(tray): use the blocking event loop to avoid wasting power (#4457)

Author: cgutman

src/main.cpp

@@ -99,32 +99,20 @@ void mainThreadLoop(const std::shared_ptr<safe::event_t<bool>> &shutdown_event)
 
   // Conditions that would require the main thread event loop
 #ifndef _WIN32
-  run_loop = tray_is_enabled;  // On Windows, tray runs in separate thread, so no main loop needed for tray
+  run_loop = tray_is_enabled && config::sunshine.system_tray;  // On Windows, tray runs in separate thread, so no main loop needed for tray
 #endif
 
   if (!run_loop) {
     BOOST_LOG(info) << "No main thread features enabled, skipping event loop"sv;
+    // Wait for shutdown
+    shutdown_event->view();
     return;
   }
 
   // Main thread event loop
   BOOST_LOG(info) << "Starting main loop"sv;
-  while (true) {
-    if (shutdown_event->peek()) {
-      BOOST_LOG(info) << "Shutdown event detected, breaking main loop"sv;
-      if (tray_is_enabled && config::sunshine.system_tray) {
-        system_tray::end_tray();
-      }
-      break;
-    }
-
-    if (tray_is_enabled) {
-      system_tray::process_tray_events();
-    }
-
-    // Sleep to avoid busy waiting
-    std::this_thread::sleep_for(std::chrono::milliseconds(50));
-  }
+  while (system_tray::process_tray_events() == 0);
+  BOOST_LOG(info) << "Main loop has exited"sv;
 }
 
 int main(int argc, char *argv[]) {
@@ -297,7 +285,10 @@ int main(int argc, char *argv[]) {
     };
     force_shutdown = task_pool.pushDelayed(task, 10s).task_id;
 
+    // Break out of the main loop
     shutdown_event->raise(true);
+    system_tray::end_tray();
+
     display_device_deinit_guard = nullptr;
   });
 
@@ -311,7 +302,10 @@ int main(int argc, char *argv[]) {
     };
     force_shutdown = task_pool.pushDelayed(task, 10s).task_id;
 
+    // Break out of the main loop
     shutdown_event->raise(true);
+    system_tray::end_tray();
+
     display_device_deinit_guard = nullptr;
   });
 
@@ -400,9 +394,6 @@ int main(int argc, char *argv[]) {
 
   mainThreadLoop(shutdown_event);
 
-  // Wait for shutdown, this is not necessary when we're using the main event loop
-  shutdown_event->view();
-
   httpThread.join();
   configThread.join();
   rtspThread.join();
@@ -416,11 +407,6 @@ int main(int argc, char *argv[]) {
     nvprefs_instance.restore_global_profile();
     nvprefs_instance.unload();
   }
-
-  // Stop the threaded tray if it was started
-  if (tray_is_enabled && config::sunshine.system_tray) {
-    system_tray::end_tray_threaded();
-  }
 #endif
 
   return lifetime::desired_exit_code;

src/system_tray.cpp

@@ -53,11 +53,6 @@ using namespace std::literals;
 namespace system_tray {
   static std::atomic tray_initialized = false;
 
-  // Threading variables for all platforms
-  static std::thread tray_thread;
-  static std::atomic tray_thread_running = false;
-  static std::atomic tray_thread_should_exit = false;
-
   void tray_open_ui_cb([[maybe_unused]] struct tray_menu *item) {
     BOOST_LOG(info) << "Opening UI from system tray"sv;
     launch_ui();
@@ -207,16 +202,12 @@ namespace system_tray {
 
   int process_tray_events() {
     if (!tray_initialized) {
+      BOOST_LOG(error) << "System tray is not initialized"sv;
       return 1;
     }
 
-    // Process one iteration of the tray loop with non-blocking mode (0)
-    if (const int result = tray_loop(0); result != 0) {
-      BOOST_LOG(warning) << "System tray loop failed"sv;
-      return result;
-    }
-
-    return 0;
+    // Block until an event is processed or tray_quit() is called
+    return tray_loop(1);
   }
 
   int end_tray() {
@@ -319,63 +310,22 @@ namespace system_tray {
     // Initialize the tray in this thread
     if (init_tray() != 0) {
       BOOST_LOG(error) << "Failed to initialize tray in thread"sv;
-      tray_thread_running = false;
       return;
     }
 
-    tray_thread_running = true;
-
     // Main tray event loop
-    while (!tray_thread_should_exit) {
-      if (process_tray_events() != 0) {
-        BOOST_LOG(warning) << "Tray event processing failed in thread"sv;
-        break;
-      }
+    while (process_tray_events() == 0);
 
-      // Sleep to avoid busy waiting
-      std::this_thread::sleep_for(std::chrono::milliseconds(50));
-    }
-
-    // Clean up the tray
-    end_tray();
-    tray_thread_running = false;
     BOOST_LOG(info) << "System tray thread ended"sv;
   }
 
   int init_tray_threaded() {
-    if (tray_thread_running) {
-      BOOST_LOG(warning) << "Tray thread is already running"sv;
-      return 1;
-    }
-
-    tray_thread_should_exit = false;
-
     try {
-      tray_thread = std::thread(tray_thread_worker);
-
-      // Wait for the thread to start and initialize
-      const auto start_time = std::chrono::steady_clock::now();
-      while (!tray_thread_running && !tray_thread_should_exit) {
-        std::this_thread::sleep_for(std::chrono::milliseconds(10));
-
-        // Timeout after 10 seconds
-        if (std::chrono::steady_clock::now() - start_time > std::chrono::seconds(10)) {
-          BOOST_LOG(error) << "Tray thread initialization timeout"sv;
-          tray_thread_should_exit = true;
-          if (tray_thread.joinable()) {
-            tray_thread.join();
-          }
-          return 1;
-        }
-      }
+      auto tray_thread = std::thread(tray_thread_worker);
 
-      if (!tray_thread_running) {
-        BOOST_LOG(error) << "Tray thread failed to start"sv;
-        if (tray_thread.joinable()) {
-          tray_thread.join();
-        }
-        return 1;
-      }
+      // The tray thread doesn't require strong lifetime management.
+      // It will exit asynchronously when tray_exit() is called.
+      tray_thread.detach();
 
       BOOST_LOG(info) << "System tray thread initialized successfully"sv;
       return 0;
@@ -385,21 +335,5 @@ namespace system_tray {
     }
   }
 
-  int end_tray_threaded() {
-    if (!tray_thread_running) {
-      return 0;
-    }
-
-    BOOST_LOG(info) << "Stopping system tray thread"sv;
-    tray_thread_should_exit = true;
-
-    if (tray_thread.joinable()) {
-      tray_thread.join();
-    }
-
-    BOOST_LOG(info) << "System tray thread stopped"sv;
-    return 0;
-  }
-
 }  // namespace system_tray
 #endif

src/system_tray.h

@@ -96,10 +96,4 @@ namespace system_tray {
    * @return 0 if initialization was successful, non-zero otherwise.
    */
   int init_tray_threaded();
-
-  /**
-   * @brief Stops the threaded system tray and waits for the thread to finish.
-   * @return 0 after stopping the threaded tray.
-   */
-  int end_tray_threaded();
 }  // namespace system_tray