Implement new AudioBackend API in PA backend to choose between callback and blocking API

2 files changed, 65 insertions, 49 deletions

diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index 0f816c991f..616ee1d145 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -66,6 +66,7 @@ PortAudioBackend::PortAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _pcmio (0)
 	, _run (false)
 	, _active (false)
+	, _use_blocking_api(false)
 	, _freewheel (false)
 	, _freewheeling (false)
 	, _freewheel_ack (false)
@@ -160,6 +161,18 @@ PortAudioBackend::update_devices ()
 	return _pcmio->update_devices();
 }
 
+void
+PortAudioBackend::set_use_buffered_io (bool use_buffered_io)
+{
+	DEBUG_AUDIO (string_compose ("Portaudio: use_buffered_io %1 \n", use_buffered_io));
+
+	if (running()) {
+		return;
+	}
+
+	_use_blocking_api = use_buffered_io;
+}
+
 std::string
 PortAudioBackend::driver_name () const
 {
@@ -572,21 +585,21 @@ PortAudioBackend::_start (bool for_latency_measurement)
 
 	PaErrorCode err = paNoError;
 
-#ifdef USE_BLOCKING_API
-	err = _pcmio->open_blocking_stream(name_to_id(_input_audio_device),
-	                                   name_to_id(_output_audio_device),
-	                                   _samplerate,
-	                                   _samples_per_period);
-
-#else
-	err = _pcmio->open_callback_stream(name_to_id(_input_audio_device),
-	                                   name_to_id(_output_audio_device),
-	                                   _samplerate,
-	                                   _samples_per_period,
-	                                   portaudio_callback,
-	                                   this);
-
-#endif
+	if (_use_blocking_api) {
+		DEBUG_AUDIO("Opening blocking audio stream\n");
+		err = _pcmio->open_blocking_stream(name_to_id(_input_audio_device),
+		                                   name_to_id(_output_audio_device),
+		                                   _samplerate,
+		                                   _samples_per_period);
+	} else {
+		DEBUG_AUDIO("Opening callback audio stream\n");
+		err = _pcmio->open_callback_stream(name_to_id(_input_audio_device),
+		                                   name_to_id(_output_audio_device),
+		                                   _samplerate,
+		                                   _samples_per_period,
+		                                   portaudio_callback,
+		                                   this);
+	}
 
 	// reintepret Portaudio error messages
 	switch (err) {
@@ -669,22 +682,22 @@ PortAudioBackend::_start (bool for_latency_measurement)
 	_run = true;
 	_port_change_flag = false;
 
-#ifdef USE_BLOCKING_API
-	if (!start_blocking_process_thread()) {
-		return ProcessThreadStartError;
-	}
-#else
-	if (_pcmio->start_stream() != paNoError) {
-		DEBUG_AUDIO("Unable to start stream\n");
-		return AudioDeviceOpenError;
-	}
+	if (_use_blocking_api) {
+		if (!start_blocking_process_thread()) {
+			return ProcessThreadStartError;
+		}
+	} else {
+		if (_pcmio->start_stream() != paNoError) {
+			DEBUG_AUDIO("Unable to start stream\n");
+			return AudioDeviceOpenError;
+		}
 
-	if (!start_freewheel_process_thread()) {
-		DEBUG_AUDIO("Unable to start freewheel thread\n");
-		stop();
-		return ProcessThreadStartError;
+		if (!start_freewheel_process_thread()) {
+			DEBUG_AUDIO("Unable to start freewheel thread\n");
+			stop();
+			return ProcessThreadStartError;
+		}
 	}
-#endif
 
 	return NoError;
 }
@@ -814,20 +827,19 @@ PortAudioBackend::stop ()
 
 	_run = false;
 
-#ifdef USE_BLOCKING_API
-	if (!stop_blocking_process_thread ()) {
-		return -1;
-	}
-#else
-	_pcmio->close_stream ();
-	_active = false;
+	if (_use_blocking_api) {
+		if (!stop_blocking_process_thread()) {
+			return -1;
+		}
+	} else {
+		_pcmio->close_stream();
+		_active = false;
 
-	if (!stop_freewheel_process_thread ()) {
-		return -1;
+		if (!stop_freewheel_process_thread()) {
+			return -1;
+		}
 	}
 
-#endif
-
 	unregister_ports();
 
 	return (_active == false) ? 0 : -1;
@@ -1127,16 +1139,15 @@ PortAudioBackend::join_process_threads ()
 bool
 PortAudioBackend::in_process_thread ()
 {
-#ifdef USE_BLOCKING_API
-	if (pthread_equal (_main_blocking_thread, pthread_self()) != 0) {
-		return true;
-	}
-#else
-	if (pthread_equal (_main_thread, pthread_self()) != 0) {
-		return true;
+	if (_use_blocking_api) {
+		if (pthread_equal(_main_blocking_thread, pthread_self()) != 0) {
+			return true;
+		}
+	} else {
+		if (pthread_equal(_main_thread, pthread_self()) != 0) {
+			return true;
+		}
 	}
-#endif
-
 	for (std::vector<pthread_t>::const_iterator i = _threads.begin (); i != _threads.end (); ++i)
 	{
 		if (pthread_equal (*i, pthread_self ()) != 0) {
diff --git a/libs/backends/portaudio/portaudio_backend.h b/libs/backends/portaudio/portaudio_backend.h
index b028dc212b..3e329a42e0 100644
--- a/libs/backends/portaudio/portaudio_backend.h
+++ b/libs/backends/portaudio/portaudio_backend.h
@@ -174,6 +174,10 @@ class PortAudioBackend : public AudioBackend {
 		bool can_request_update_devices () { return true; }
 		bool update_devices ();
 
+		bool can_use_buffered_io () { return true; }
+		void set_use_buffered_io (bool);
+		bool get_use_buffered_io () { return _use_blocking_api; }
+
 		bool use_separate_input_and_output_devices () const;
 		std::vector<DeviceStatus> enumerate_devices () const;
 		std::vector<DeviceStatus> enumerate_input_devices () const;
@@ -356,6 +360,7 @@ class PortAudioBackend : public AudioBackend {
 
 		bool  _run; /* keep going or stop, ardour thread */
 		bool  _active; /* is running, process thread */
+		bool  _use_blocking_api;
 		bool  _freewheel;
 		bool  _freewheeling;
 		bool  _freewheel_ack;