Make std::jthread support conditional based on C++ 201911L

Sources/CSFBAudioEngine/Player/AudioPlayer.h

@@ -10,7 +10,9 @@
 #import <deque>
 #import <memory>
 #import <mutex>
+#if defined(__has_include) && __has_include(<stop_token>)
 #import <stop_token>
+#endif /* defined(__has_include) && __has_include(<stop_token>) */
 #import <thread>
 #import <vector>
 
@@ -67,12 +69,20 @@ class AudioPlayer final {
 	mutable CXXUnfairLock::UnfairLock 		queuedDecodersLock_;
 
 	/// Thread used for decoding
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 	std::jthread 							decodingThread_;
+#else
+	std::thread 							decodingThread_;
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
 	/// Dispatch semaphore used for communication with the decoding thread
 	dispatch_semaphore_t					decodingSemaphore_ 	{};
 
 	/// Thread used for event processing
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 	std::jthread 							eventThread_;
+#else
+	std::thread 							eventThread_;
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
 	/// Dispatch semaphore used for communication with the event processing thread
 	dispatch_semaphore_t					eventSemaphore_ 	{};
 
@@ -256,6 +266,12 @@ class AudioPlayer final {
 		unmuteAfterDequeue 			= 1u << 4,
 		/// Mismatch between rendering format and decoder processing format
 		formatMismatch 				= 1u << 5,
+#if !(defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L)
+		/// The decoding thread should exit
+		stopDecodingThread			= 1u << 6,
+		/// The event thread should exit
+		stopEventThread				= 1u << 7,
+#endif /* !(defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L) */
 	};
 
 	// MARK: - Decoding

Sources/CSFBAudioEngine/Player/AudioPlayer.mm

@@ -407,8 +407,13 @@ bool PerformSeekIfRequired() noexcept
 
 	// Launch the decoding and event processing threads
 	try {
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 		decodingThread_ = std::jthread(std::bind_front(&SFB::AudioPlayer::ProcessDecoders, this));
 		eventThread_ = std::jthread(std::bind_front(&SFB::AudioPlayer::SequenceAndProcessEvents, this));
+#else
+		decodingThread_ = std::thread(&SFB::AudioPlayer::ProcessDecoders, this);
+		eventThread_ = std::thread(&SFB::AudioPlayer::SequenceAndProcessEvents, this);
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
 	} catch(const std::exception& e) {
 		os_log_error(log_, "Unable to create thread: %{public}s", e.what());
 		throw;
@@ -454,26 +459,41 @@ bool PerformSeekIfRequired() noexcept
 
 	Stop();
 
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 	// Register a stop callback for the decoding thread
 	std::stop_callback decodingThreadStopCallback(decodingThread_.get_stop_token(), [this] {
 		dispatch_semaphore_signal(decodingSemaphore_);
 	});
 
 	// Issue a stop request to the decoding thread and wait for it to exit
 	decodingThread_.request_stop();
+#else
+	// Stop the decoding thread
+	flags_.fetch_or(static_cast<unsigned int>(Flags::stopDecodingThread), std::memory_order_acq_rel);
+	dispatch_semaphore_signal(decodingSemaphore_);
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
+
 	try {
 		decodingThread_.join();
 	} catch(const std::exception& e) {
 		os_log_error(log_, "Unable to join decoding thread: %{public}s", e.what());
 	}
 
+
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 	// Register a stop callback for the event processing thread
 	std::stop_callback eventThreadStopCallback(eventThread_.get_stop_token(), [this] {
 		dispatch_semaphore_signal(eventSemaphore_);
 	});
 
 	// Issue a stop request to the event processing thread and wait for it to exit
 	eventThread_.request_stop();
+#else
+	// Stop the event processing thread
+	flags_.fetch_or(static_cast<unsigned int>(Flags::stopEventThread), std::memory_order_acq_rel);
+	dispatch_semaphore_signal(eventSemaphore_);
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
+
 	try {
 		eventThread_.join();
 	} catch(const std::exception& e) {
@@ -978,7 +998,11 @@ bool PerformSeekIfRequired() noexcept
 
 // MARK: - Decoding
 
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 void SFB::AudioPlayer::ProcessDecoders(std::stop_token stoken) noexcept
+#else
+void SFB::AudioPlayer::ProcessDecoders() noexcept
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
 {
 	pthread_setname_np("AudioPlayer.Decoding");
 	pthread_set_qos_class_self_np(QOS_CLASS_USER_INITIATED, 0);
@@ -1017,7 +1041,13 @@ bool PerformSeekIfRequired() noexcept
 		}
 
 		// Terminate the thread if requested after processing cancelations
-		if(stoken.stop_requested())
+		if(
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
+		   stoken.stop_requested()
+#else
+		   flags_.load(std::memory_order_acquire) & static_cast<unsigned int>(Flags::stopDecodingThread)
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
+		   )
 			break;
 
 		// Process pending seeks
@@ -1344,14 +1374,24 @@ bool PerformSeekIfRequired() noexcept
 
 // MARK: - Event Processing
 
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
 void SFB::AudioPlayer::SequenceAndProcessEvents(std::stop_token stoken) noexcept
+#else
+void SFB::AudioPlayer::SequenceAndProcessEvents() noexcept
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
 {
 	pthread_setname_np("AudioPlayer.Events");
 	pthread_set_qos_class_self_np(QOS_CLASS_USER_INITIATED, 0);
 
 	os_log_debug(log_, "<AudioPlayer: %p> event processing thread starting", this);
 
-	while(!stoken.stop_requested()) {
+	while(
+#if defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L
+		  !stoken.stop_requested()
+#else
+		  !(flags_.load(std::memory_order_acquire) & static_cast<unsigned int>(Flags::stopEventThread))
+#endif /* defined(__cpp_lib_jthread) && __cpp_lib_jthread >= 201911L */
+		  ) {
 		auto decodeEventHeader = decodeEventRingBuffer_.ReadValue<DecodingEventHeader>();
 		auto renderEventHeader = renderEventRingBuffer_.ReadValue<RenderingEventHeader>();