Audio: Improve buffer signaling

This should stop the deadlocks which were occurring.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Audio/Chain/BufferChain.m

@@ -201,7 +201,7 @@
 - (void)dealloc {
 	[inputNode setShouldContinue:NO];
 	[[inputNode exitAtTheEndOfTheStream] signal];
-	[[inputNode semaphore] signal];
+	[[inputNode writeSemaphore] signal];
 	if(![inputNode threadExited])
 		[[inputNode exitAtTheEndOfTheStream] wait]; // wait for decoder to be closed (see InputNode's -(void)process )
 

Audio/Chain/ChunkList.m

@@ -459,7 +459,7 @@ static void convert_be_to_le(uint8_t *buffer, size_t bitsPerSample, size_t bytes
 
 - (BOOL)isFull {
 	@synchronized (chunkList) {
-		return (maxDuration - listDuration) < 0.05;
+		return (maxDuration - listDuration) < 0.001;
 	}
 }
 
@@ -588,7 +588,6 @@ static void convert_be_to_le(uint8_t *buffer, size_t bitsPerSample, size_t bytes
 			if(block()) {
 				break;
 			}
-			usleep(500);
 			continue;
 		}
 		if(formatSet &&
@@ -608,7 +607,6 @@ static void convert_be_to_le(uint8_t *buffer, size_t bitsPerSample, size_t bytes
 			if(block()) {
 				break;
 			}
-			usleep(500);
 			continue;
 		}
 

Audio/Chain/ConverterNode.m

@@ -482,6 +482,7 @@ static float db_to_scale(float db) {
 
 	paused = NO;
 	[self cleanUp];
+	[super cleanUp];
 }
 
 - (void)setOutputFormat:(AudioStreamBasicDescription)format {

Audio/Chain/DSP/DSPDownmixNode.m

@@ -38,6 +38,7 @@
 - (void)dealloc {
 	DLog(@"Downmix dealloc");
 	[self cleanUp];
+	[super cleanUp];
 }
 
 - (BOOL)fullInit {

Audio/Chain/DSP/DSPEqualizerNode.m

@@ -157,6 +157,7 @@ static OSStatus eqRenderCallback(void *inRefCon, AudioUnitRenderActionFlags *ioA
 	DLog(@"Equalizer dealloc");
 	[self cleanUp];
 	[self removeObservers];
+	[super cleanUp];
 }
 
 - (void)addObservers {

Audio/Chain/DSP/DSPFSurroundNode.m

@@ -55,6 +55,7 @@ static void * kDSPFSurroundNodeContext = &kDSPFSurroundNodeContext;
 	DLog(@"FreeSurround dealloc");
 	[self cleanUp];
 	[self removeObservers];
+	[super cleanUp];
 }
 
 - (void)addObservers {

Audio/Chain/DSP/DSPHRTFNode.m

@@ -130,6 +130,7 @@ static void unregisterMotionListener(void) {
 	DLog(@"HRTF dealloc");
 	[self cleanUp];
 	[self removeObservers];
+	[super cleanUp];
 }
 
 - (void)addObservers {

Audio/Chain/DSP/DSPRubberbandNode.m

@@ -65,6 +65,7 @@ static void * kDSPRubberbandNodeContext = &kDSPRubberbandNodeContext;
 	DLog(@"Rubber Band dealloc");
 	[self cleanUp];
 	[self removeObservers];
+	[super cleanUp];
 }
 
 - (void)addObservers {

Audio/Chain/DSPNode.m

@@ -16,7 +16,8 @@
 	if(self) {
 		buffer = [[ChunkList alloc] initWithMaximumDuration:latency];
 
-		semaphore = [[Semaphore alloc] init];
+		writeSemaphore = [[Semaphore alloc] init];
+		readSemaphore = [[Semaphore alloc] init];
 
 		accessLock = [[NSLock alloc] init];
 
@@ -31,6 +32,11 @@
 
 		durationPrebuffer = latency * 0.25;
 
+		inWrite = NO;
+		inPeek = NO;
+		inRead = NO;
+		inMerge = NO;
+
 		[self setPreviousNode:p];
 	}
 

Audio/Chain/InputNode.m

@@ -246,7 +246,7 @@ static void *kInputNodeContext = &kInputNodeContext;
 	seekFrame = frame;
 	shouldSeek = YES;
 	DLog(@"Should seek!");
-	[semaphore signal];
+	[writeSemaphore signal];
 
 	if(endOfStream) {
 		[exitAtTheEndOfTheStream signal];
@@ -280,6 +280,7 @@ static void *kInputNodeContext = &kInputNodeContext;
 - (void)dealloc {
 	DLog(@"Input Node dealloc");
 	[self removeObservers];
+	[super cleanUp];
 }
 
 - (NSDictionary *)properties {

Audio/Chain/Node.h

@@ -17,7 +17,8 @@
 
 @interface Node : NSObject {
 	ChunkList *buffer;
-	Semaphore *semaphore;
+	Semaphore *writeSemaphore;
+	Semaphore *readSemaphore;
 
 	NSLock *accessLock;
 
@@ -26,6 +27,11 @@
 
 	BOOL shouldReset;
 
+	BOOL inWrite;
+	BOOL inPeek;
+	BOOL inRead;
+	BOOL inMerge;
+
 	BOOL shouldContinue;
 	BOOL endOfStream; // All data is now in buffer
 	BOOL initialBufferFilled;
@@ -38,6 +44,8 @@
 }
 - (id _Nullable)initWithController:(id _Nonnull)c previous:(id _Nullable)p;
 
+- (void)cleanUp;
+
 - (void)writeData:(const void *_Nonnull)ptr amount:(size_t)a;
 - (void)writeChunk:(AudioChunk *_Nonnull)chunk;
 - (AudioChunk *_Nonnull)readChunk:(size_t)maxFrames;
@@ -70,7 +78,8 @@
 - (uint32_t)nodeChannelConfig;
 - (BOOL)nodeLossless;
 
-- (Semaphore *_Nonnull)semaphore;
+- (Semaphore *_Nonnull)writeSemaphore;
+- (Semaphore *_Nonnull)readSemaphore;
 
 //-(void)resetBuffer;
 

Audio/Chain/Node.m

@@ -23,7 +23,8 @@
 	self = [super init];
 	if(self) {
 		buffer = [[ChunkList alloc] initWithMaximumDuration:10.0];
-		semaphore = [[Semaphore alloc] init];
+		writeSemaphore = [[Semaphore alloc] init];
+		readSemaphore = [[Semaphore alloc] init];
 
 		accessLock = [[NSLock alloc] init];
 
@@ -38,12 +39,32 @@
 
 		durationPrebuffer = 2.0;
 
+		inWrite = NO;
+		inPeek = NO;
+		inRead = NO;
+		inMerge = NO;
+
 		[self setPreviousNode:p];
 	}
 
 	return self;
 }
 
+- (void)dealloc {
+	[self cleanUp];
+}
+
+- (void)cleanUp {
+	[self setShouldContinue:NO];
+	while(inWrite || inPeek || inRead || inMerge) {
+		[writeSemaphore signal];
+		if(previousNode) {
+			[[previousNode readSemaphore] signal];
+		}
+		usleep(500);
+	}
+}
+
 - (AudioStreamBasicDescription)nodeFormat {
 	return nodeFormat;
 }
@@ -57,6 +78,12 @@
 }
 
 - (void)writeData:(const void *)ptr amount:(size_t)amount {
+	inWrite = YES;
+	if(!shouldContinue) {
+		inWrite = NO;
+		return;
+	}
+
 	[accessLock lock];
 
 	AudioChunk *chunk = [[AudioChunk alloc] init];
@@ -78,22 +105,38 @@
 		}
 	}
 
-	while(shouldContinue == YES && durationLeft <= 0.0) {
-		if(durationLeft <= 0.0 || shouldReset) {
+	while(shouldContinue == YES && durationLeft < 0.0) {
+		if(durationLeft < 0.0 || shouldReset) {
 			[accessLock unlock];
-			[semaphore wait];
+			[writeSemaphore timedWait:2000];
 			[accessLock lock];
 		}
 
 		durationLeft = [buffer maxDuration] - [buffer listDuration];
 	}
 
-	[buffer addChunk:chunk];
+	BOOL doSignal = NO;
+	if([chunk frameCount]) {
+		[buffer addChunk:chunk];
+		doSignal = YES;
+	}
 
 	[accessLock unlock];
+
+	if(doSignal) {
+		[readSemaphore signal];
+	}
+
+	inWrite = NO;
 }
 
 - (void)writeChunk:(AudioChunk *)chunk {
+	inWrite = YES;
+	if(!shouldContinue) {
+		inWrite = NO;
+		return;
+	}
+
 	[accessLock lock];
 
 	double durationList = [buffer listDuration];
@@ -107,24 +150,34 @@
 		}
 	}
 
-	while(shouldContinue == YES && durationLeft <= 0.0) {
+	while(shouldContinue == YES && durationLeft < 0.0) {
 		if(previousNode && [previousNode shouldContinue] == NO) {
 			shouldContinue = NO;
 			break;
 		}
 
-		if(durationLeft <= 0.0 || shouldReset) {
+		if(durationLeft < 0.0 || shouldReset) {
 			[accessLock unlock];
-			[semaphore wait];
+			[writeSemaphore timedWait:2000];
 			[accessLock lock];
 		}
 
 		durationLeft = [buffer maxDuration] - [buffer listDuration];
 	}
 
-	[buffer addChunk:chunk];
+	BOOL doSignal = NO;
+	if([chunk frameCount]) {
+		[buffer addChunk:chunk];
+		doSignal = YES;
+	}
 
 	[accessLock unlock];
+
+	if(doSignal) {
+		[readSemaphore signal];
+	}
+
+	inWrite = NO;
 }
 
 // Should be overwriten by subclass.
@@ -138,11 +191,30 @@
 }
 
 - (BOOL)peekFormat:(nonnull AudioStreamBasicDescription *)format channelConfig:(nonnull uint32_t *)config {
+	inPeek = YES;
+	if(!shouldContinue) {
+		inPeek = NO;
+		return NO;
+	}
+
 	[accessLock lock];
 
+	while(shouldContinue && [[previousNode buffer] isEmpty] && [previousNode endOfStream] == NO) {
+		[accessLock unlock];
+		[[previousNode readSemaphore] timedWait:2000];
+		[accessLock lock];
+	}
+
+	if(!shouldContinue) {
+		[accessLock unlock];
+		inPeek = NO;
+		return NO;
+	}
+
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inPeek = NO;
 		return NO;
 	}
 
@@ -150,15 +222,36 @@
 
 	[accessLock unlock];
 
+	inPeek = NO;
+
 	return ret;
 }
 
 - (BOOL)peekTimestamp:(double *_Nonnull)timestamp timeRatio:(double *_Nonnull)timeRatio {
+	inPeek = YES;
+	if(!shouldContinue) {
+		inPeek = NO;
+		return NO;
+	}
+
 	[accessLock lock];
 
+	while(shouldContinue && [[previousNode buffer] isEmpty] && [previousNode endOfStream] == NO) {
+		[accessLock unlock];
+		[[previousNode readSemaphore] timedWait:2000];
+		[accessLock lock];
+	}
+
+	if(!shouldContinue) {
+		[accessLock unlock];
+		inPeek = NO;
+		return NO;
+	}
+
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inPeek = NO;
 		return NO;
 	}
 
@@ -166,15 +259,39 @@
 
 	[accessLock unlock];
 
+	inPeek = NO;
+
 	return ret;
 }
 
 - (AudioChunk *)readChunk:(size_t)maxFrames {
+	inRead = YES;
+	if(!shouldContinue) {
+		inRead = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	[accessLock lock];
 
+	while(shouldContinue && [[previousNode buffer] isEmpty] && [previousNode endOfStream] == NO) {
+		[accessLock unlock];
+		[[previousNode readSemaphore] timedWait:2000];
+		[accessLock lock];
+		if([previousNode shouldReset] == YES) {
+			break;
+		}
+	}
+
+	if(!shouldContinue) {
+		[accessLock unlock];
+		inRead = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inRead = NO;
 		return [[AudioChunk alloc] init];
 	}
 
@@ -186,7 +303,7 @@
 		shouldReset = YES;
 		[previousNode setShouldReset:NO];
 
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
 	AudioChunk *ret;
@@ -198,18 +315,42 @@
 	[accessLock unlock];
 
 	if([ret frameCount]) {
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
+	inRead = NO;
+
 	return ret;
 }
 
 - (AudioChunk *)readChunkAsFloat32:(size_t)maxFrames {
+	inRead = YES;
+	if(!shouldContinue) {
+		inRead = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	[accessLock lock];
 
+	while(shouldContinue && [[previousNode buffer] isEmpty] && [previousNode endOfStream] == NO) {
+		[accessLock unlock];
+		[[previousNode readSemaphore] timedWait:2000];
+		[accessLock lock];
+		if([previousNode shouldReset] == YES) {
+			break;
+		}
+	}
+
+	if(!shouldContinue) {
+		[accessLock unlock];
+		inRead = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inRead = NO;
 		return [[AudioChunk alloc] init];
 	}
 
@@ -221,7 +362,7 @@
 		shouldReset = YES;
 		[previousNode setShouldReset:NO];
 
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
 	AudioChunk *ret;
@@ -233,83 +374,109 @@
 	[accessLock unlock];
 
 	if([ret frameCount]) {
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
+	inRead = NO;
+
 	return ret;
 }
 
 - (AudioChunk *)readAndMergeChunks:(size_t)maxFrames {
+	inMerge = YES;
+	if(!shouldContinue) {
+		inMerge = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	[accessLock lock];
 
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inMerge = NO;
 		return [[AudioChunk alloc] init];
 	}
 
-	if([previousNode shouldReset] == YES) {
-		@autoreleasepool {
-			[buffer reset];
-		}
-
-		shouldReset = YES;
-		[previousNode setShouldReset:NO];
-
-		[[previousNode semaphore] signal];
-	}
-
-	[accessLock unlock];
-
 	AudioChunk *ret;
 
 	@autoreleasepool {
 		ret = [[previousNode buffer] removeAndMergeSamples:maxFrames callBlock:^BOOL{
-			return [[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES;
+			if([previousNode shouldReset] == YES) {
+				@autoreleasepool {
+					[buffer reset];
+				}
+
+				shouldReset = YES;
+				[previousNode setShouldReset:NO];
+			}
+
+			[accessLock unlock];
+			[[previousNode writeSemaphore] signal];
+			[[previousNode readSemaphore] timedWait:2000];
+			[accessLock lock];
+
+			return !shouldContinue || ([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES);
 		}];
 	}
 
+	[accessLock unlock];
+
 	if([ret frameCount]) {
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
+	inMerge = NO;
+
 	return ret;
 }
 
 - (AudioChunk *)readAndMergeChunksAsFloat32:(size_t)maxFrames {
+	inMerge = YES;
+	if(!shouldContinue) {
+		inMerge = NO;
+		return [[AudioChunk alloc] init];
+	}
+
 	[accessLock lock];
 
 	if([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES) {
 		endOfStream = YES;
 		[accessLock unlock];
+		inMerge = NO;
 		return [[AudioChunk alloc] init];
 	}
 
-	if([previousNode shouldReset] == YES) {
-		@autoreleasepool {
-			[buffer reset];
-		}
-
-		shouldReset = YES;
-		[previousNode setShouldReset:NO];
-
-		[[previousNode semaphore] signal];
-	}
-
-	[accessLock unlock];
-
 	AudioChunk *ret;
 
 	@autoreleasepool {
 		ret = [[previousNode buffer] removeAndMergeSamplesAsFloat32:maxFrames callBlock:^BOOL{
-			return [[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES;
+			if([previousNode shouldReset] == YES) {
+				@autoreleasepool {
+					[buffer reset];
+				}
+
+				shouldReset = YES;
+				[previousNode setShouldReset:NO];
+			}
+
+			[accessLock unlock];
+			[[previousNode writeSemaphore] signal];
+			[[previousNode readSemaphore] timedWait:2000];
+			[accessLock lock];
+
+			return !shouldContinue || ([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES);
 		}];
 	}
 
+	[accessLock unlock];
+
 	if([ret frameCount]) {
-		[[previousNode semaphore] signal];
+		[[previousNode writeSemaphore] signal];
 	}
 
+	inMerge = NO;
+
 	return ret;
 }
 
@@ -348,8 +515,12 @@
 	}
 }
 
-- (Semaphore *)semaphore {
-	return semaphore;
+- (Semaphore *)writeSemaphore {
+	return writeSemaphore;
+}
+
+- (Semaphore *)readSemaphore {
+	return readSemaphore;
 }
 
 - (BOOL)endOfStream {

Audio/Chain/VisualizationNode.m

@@ -111,7 +111,8 @@ static VisualizationCollection *theCollection = nil;
 	if(self) {
 		buffer = [[ChunkList alloc] initWithMaximumDuration:latency];
 
-		semaphore = [[Semaphore alloc] init];
+		writeSemaphore = [[Semaphore alloc] init];
+		readSemaphore = [[Semaphore alloc] init];
 
 		accessLock = [[NSLock alloc] init];
 
@@ -133,6 +134,11 @@ static VisualizationCollection *theCollection = nil;
 		replay = NO;
 		prerollBuffer = [[NSMutableData alloc] init];
 
+		inWrite = NO;
+		inPeek = NO;
+		inRead = NO;
+		inMerge = NO;
+
 		[self setPreviousNode:p];
 	}
 
@@ -143,6 +149,7 @@ static VisualizationCollection *theCollection = nil;
 	DLog(@"Visualization node dealloc");
 	[self cleanUp];
 	[self pop];
+	[super cleanUp];
 }
 
 - (void)pop {