Cog Audio: Dealt with a major retain cycle leak

This seals up a major memory leak of the playback state whenever a chain
is released on stop or on manual track change. CogAudioMulti was
retaining the input node due to its listeners, and InputNode was not
releasing the listeners when asked to stop running. This is fixed now.

Fixes #221

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

Audio/AudioPlayer.m

@@ -68,7 +68,10 @@
     ALog(@"Opening file for playback: %@ at seek offset %f%@", url, time, (paused) ? @", starting paused" : @"");
     
     [self waitUntilCallbacksExit];
-    output = nil;
+    if (output) {
+        [output setShouldContinue:NO];
+        output = nil;
+    }
     output = [[OutputNode alloc] initWithController:self previous:nil];
     [output setup];
     [output setVolume: volume];
@@ -135,6 +138,20 @@
 	//Set shouldoContinue to NO on all things
 	[self setShouldContinue:NO];
 	[self setPlaybackStatus:CogStatusStopped waitUntilDone:YES];
+
+    @synchronized(chainQueue) {
+        for (id anObject in chainQueue)
+        {
+            [anObject setShouldContinue:NO];
+        }
+        [chainQueue removeAllObjects];
+        endOfInputReached = NO;
+        if (bufferChain)
+        {
+            bufferChain = nil;
+        }
+    }
+    output = nil;
 }
 
 - (void)pause

Audio/Chain/InputNode.h

@@ -28,6 +28,8 @@
 	
 	BOOL shouldSeek;
 	long seekFrame;
+    
+    BOOL observersAdded;
 
     Semaphore *exitAtTheEndOfTheStream;
 }

Audio/Chain/InputNode.m

@@ -90,6 +90,8 @@
 			  forKeyPath:@"metadata" 
 				 options:(NSKeyValueObservingOptionNew)
 				 context:NULL];
+    
+    observersAdded = YES;
 }
 
 - (void)observeValueForKeyPath:(NSString *)keyPath
@@ -219,8 +221,19 @@
 
 - (void)removeObservers
 {
-    [decoder removeObserver:self forKeyPath:@"properties"];
-    [decoder removeObserver:self forKeyPath:@"metadata"];
+    if (observersAdded)
+    {
+        [decoder removeObserver:self forKeyPath:@"properties"];
+        [decoder removeObserver:self forKeyPath:@"metadata"];
+        observersAdded = NO;
+    }
+}
+
+- (void)setShouldContinue:(BOOL)s
+{
+    [super setShouldContinue:s];
+    if (!s)
+        [self removeObservers];
 }
 
 - (void)dealloc

Audio/Chain/OutputNode.m

@@ -137,6 +137,7 @@
 - (void)close
 {
 	[output stop];
+    output = nil;
 }
 
 - (void)setVolume:(double) v

Audio/CogPluginMulti.m

@@ -108,10 +108,11 @@ NSArray * sortClassesByPriority(NSArray * theClasses)
 - (void)close
 {
     if ( theDecoder != nil ) {
-        [theDecoder close];
         for (NSDictionary *obsItem in cachedObservers) {
             [theDecoder removeObserver:[obsItem objectForKey:@"observer"] forKeyPath:[obsItem objectForKey:@"keyPath"]];
         }
+        [cachedObservers removeAllObjects];
+        [theDecoder close];
         theDecoder = nil;
     }
 }

Audio/Output/OutputCoreAudio.h

@@ -46,6 +46,7 @@
     atomic_long bytesHdcdSustained;
     
     BOOL listenerapplied;
+    BOOL observersapplied;
     
     float volume;
     

Audio/Output/OutputCoreAudio.m

@@ -174,10 +174,7 @@ static OSStatus renderCallback( void *inRefCon, AudioUnitRenderActionFlags *ioAc
 #ifdef OUTPUT_LOG
         _logFile = fopen("/tmp/CogAudioLog.raw", "wb");
 #endif
-        
-		[[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.outputDevice" options:0 context:NULL];
-        [[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.GraphicEQenable" options:0 context:NULL];
-	}
+    }
 	
 	return self;
 }
@@ -704,6 +701,10 @@ default_device_changed(AudioObjectID inObjectID, UInt32 inNumberAddresses, const
     
     [_au allocateRenderResourcesAndReturnError:&err];
     
+    [[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.outputDevice" options:0 context:NULL];
+    [[NSUserDefaultsController sharedUserDefaultsController] addObserver:self forKeyPath:@"values.GraphicEQenable" options:0 context:NULL];
+    observersapplied = YES;
+    
 	return (err == nil);
 }
 
@@ -732,6 +733,12 @@ default_device_changed(AudioObjectID inObjectID, UInt32 inNumberAddresses, const
 
 - (void)stop
 {
+    stopInvoked = YES;
+    if (observersapplied) {
+        observersapplied = NO;
+        [[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.outputDevice"];
+        [[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.GraphicEQenable"];
+    }
     if (stopNext && started && !paused) {
         while (![[outputController buffer] isEmpty]) {
             [writeSemaphore signal];
@@ -743,7 +750,6 @@ default_device_changed(AudioObjectID inObjectID, UInt32 inNumberAddresses, const
         stopNext = NO;
         [self signalEndOfStream];
     }
-    stopInvoked = YES;
     stopping = YES;
     paused = NO;
     [writeSemaphore signal];
@@ -782,14 +788,13 @@ default_device_changed(AudioObjectID inObjectID, UInt32 inNumberAddresses, const
         _logFile = NULL;
     }
 #endif
+    outputController = nil;
 }
 
 - (void)dealloc
 {
-    [self stop];
-    
-	[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.outputDevice"];
-    [[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.GraphicEQenable"];
+    if (!stopInvoked)
+        [self stop];
 }
 
 - (void)pause