From 2f0c923c29a3885733d170f67d08fcd0f9ba1ebe Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 22 Feb 2017 21:42:10 -0500
Subject: [PATCH] Switched away from @synchronized as it appears possibly to be
 the lock used during -dealloc, creating deadlock with the
 CSAudioQueueDeallocLock.

---
 .../Mac/Clock Signal/Audio/CSAudioQueue.m     | 53 ++++++++++---------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m b/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m
index 1c6bd4990..83280ad8b 100644
--- a/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m	
+++ b/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m	
@@ -17,8 +17,8 @@ static NSLock *CSAudioQueueDeallocLock;
 @implementation CSAudioQueue
 {
 	AudioQueueRef _audioQueue;
-
 	AudioQueueBufferRef _storedBuffers[NumberOfStoredAudioQueueBuffer];
+	NSLock *_storedBuffersLock;
 }
 
 #pragma mark - AudioQueue callbacks
@@ -27,18 +27,18 @@ static NSLock *CSAudioQueueDeallocLock;
 {
 	[self.delegate audioQueueIsRunningDry:self];
 
-	@synchronized(self)
+	[_storedBuffersLock lock];
+	for(int c = 0; c < NumberOfStoredAudioQueueBuffer; c++)
 	{
-		for(int c = 0; c < NumberOfStoredAudioQueueBuffer; c++)
+		if(!_storedBuffers[c] || buffer->mAudioDataBytesCapacity > _storedBuffers[c]->mAudioDataBytesCapacity)
 		{
-			if(!_storedBuffers[c] || buffer->mAudioDataBytesCapacity > _storedBuffers[c]->mAudioDataBytesCapacity)
-			{
-				if(_storedBuffers[c]) AudioQueueFreeBuffer(_audioQueue, _storedBuffers[c]);
-				_storedBuffers[c] = buffer;
-				return;
-			}
+			if(_storedBuffers[c]) AudioQueueFreeBuffer(_audioQueue, _storedBuffers[c]);
+			_storedBuffers[c] = buffer;
+			[_storedBuffersLock unlock];
+			return;
 		}
 	}
+	[_storedBuffersLock unlock];
 	AudioQueueFreeBuffer(_audioQueue, buffer);
 }
 
@@ -66,6 +66,7 @@ static void audioOutputCallback(
 		{
 			CSAudioQueueDeallocLock = [[NSLock alloc] init];
 		}
+		_storedBuffersLock = [[NSLock alloc] init];
 
 		_samplingRate = samplingRate;
 
@@ -126,28 +127,28 @@ static void audioOutputCallback(
 {
 	size_t bufferBytes = lengthInSamples * sizeof(int16_t);
 
-	@synchronized(self)
+	[_storedBuffersLock lock];
+	for(int c = 0; c < NumberOfStoredAudioQueueBuffer; c++)
 	{
-		for(int c = 0; c < NumberOfStoredAudioQueueBuffer; c++)
+		if(_storedBuffers[c] && _storedBuffers[c]->mAudioDataBytesCapacity >= bufferBytes)
 		{
-			if(_storedBuffers[c] && _storedBuffers[c]->mAudioDataBytesCapacity >= bufferBytes)
-			{
-				memcpy(_storedBuffers[c]->mAudioData, buffer, bufferBytes);
-				_storedBuffers[c]->mAudioDataByteSize = (UInt32)bufferBytes;
+			memcpy(_storedBuffers[c]->mAudioData, buffer, bufferBytes);
+			_storedBuffers[c]->mAudioDataByteSize = (UInt32)bufferBytes;
 
-				AudioQueueEnqueueBuffer(_audioQueue, _storedBuffers[c], 0, NULL);
-				_storedBuffers[c] = NULL;
-				return;
-			}
+			AudioQueueEnqueueBuffer(_audioQueue, _storedBuffers[c], 0, NULL);
+			_storedBuffers[c] = NULL;
+			[_storedBuffersLock unlock];
+			return;
 		}
-
-		AudioQueueBufferRef newBuffer;
-		AudioQueueAllocateBuffer(_audioQueue, (UInt32)bufferBytes * 2, &newBuffer);
-		memcpy(newBuffer->mAudioData, buffer, bufferBytes);
-		newBuffer->mAudioDataByteSize = (UInt32)bufferBytes;
-
-		AudioQueueEnqueueBuffer(_audioQueue, newBuffer, 0, NULL);
 	}
+	[_storedBuffersLock unlock];
+
+	AudioQueueBufferRef newBuffer;
+	AudioQueueAllocateBuffer(_audioQueue, (UInt32)bufferBytes * 2, &newBuffer);
+	memcpy(newBuffer->mAudioData, buffer, bufferBytes);
+	newBuffer->mAudioDataByteSize = (UInt32)bufferBytes;
+
+	AudioQueueEnqueueBuffer(_audioQueue, newBuffer, 0, NULL);
 }
 
 #pragma mark - Sampling Rate getters