Fix/cue playback failure handling

Audio/AudioPlayer.h

@@ -122,6 +122,7 @@
 - (void)endOfInputPlayed;
 - (void)reportPlayCount;
 - (void)reportScrobble;
+- (void)setError:(BOOL)status forTrack:(id)userInfo;
 - (void)sendDelegateMethod:(SEL)selector withVoid:(void *)obj waitUntilDone:(BOOL)wait;
 - (void)sendDelegateMethod:(SEL)selector withObject:(id)obj waitUntilDone:(BOOL)wait;
 - (void)sendDelegateMethod:(SEL)selector withObject:(id)obj withObject:(id)obj2 waitUntilDone:(BOOL)wait;

Audio/AudioPlayer.m

@@ -15,6 +15,25 @@
 
 #import "Logging.h"
 
+static NSURL *streamURLWithoutFragment(NSURL *url) {
+	if(!url || ![[url fragment] length]) {
+		return url;
+	}
+
+	NSURLComponents *components = [NSURLComponents componentsWithURL:url resolvingAgainstBaseURL:NO];
+	components.fragment = nil;
+	return components.URL;
+}
+
+static BOOL streamURLsShareUnderlyingResource(NSURL *firstURL, NSURL *secondURL) {
+	NSURL *firstResource = streamURLWithoutFragment(firstURL);
+	NSURL *secondResource = streamURLWithoutFragment(secondURL);
+	if(!firstResource || !secondResource) {
+		return NO;
+	}
+	return [firstResource isEqualTo:secondResource];
+}
+
 @implementation AudioPlayer {
 	BOOL stoppedRecently;
 }
@@ -106,7 +125,23 @@ - (void)play:(NSURL *)url withUserInfo:(id)userInfo withRGInfo:(NSDictionary *)r
 		[self notifyStreamChanged:userInfo];
 	}
 
-	while(![bufferChain open:url withOutputFormat:[output format] withUserInfo:userInfo withRGInfo:rgi resetBuffers:YES]) {
+	NSURL *failedFragmentResource = nil;
+	BOOL advancedPastFailedStream = NO;
+	while(YES) {
+		BOOL skipRepeatedProbe = failedFragmentResource && streamURLsShareUnderlyingResource(failedFragmentResource, url);
+		if(!skipRepeatedProbe && [bufferChain open:url withOutputFormat:[output format] withUserInfo:userInfo withRGInfo:rgi resetBuffers:YES]) {
+			break;
+		}
+
+		if(skipRepeatedProbe) {
+			DLog(@"Skipping another logical track from failed source: %@", url);
+		} else {
+			// Logical tracks with different fragments share one decoder source. If
+			// that source cannot be opened, probing every remaining fragment repeats
+			// the same expensive failure while this method blocks the main thread.
+			failedFragmentResource = [[url fragment] length] ? streamURLWithoutFragment(url) : nil;
+		}
+		[self setError:YES forTrack:userInfo];
 		bufferChain = nil;
 
 		[self requestNextStream:userInfo];
@@ -122,11 +157,15 @@ - (void)play:(NSURL *)url withUserInfo:(id)userInfo withRGInfo:(NSDictionary *)r
 
 		userInfo = nextStreamUserInfo;
 		rgi = nextStreamRGInfo;
-
-		[self notifyStreamChanged:userInfo];
+		advancedPastFailedStream = YES;
 
 		bufferChain = [[BufferChain alloc] initWithController:self];
 	}
+	if(advancedPastFailedStream) {
+		// Do not present every failed fallback as the current track. Publish only
+		// the first stream that actually opened.
+		[self notifyStreamChanged:userInfo];
+	}
 
 	if(resumeInterval || time > 0.0) {
 		[output seek:time];
@@ -686,8 +725,11 @@ - (void)sustainHDCD {
 //	[self sendDelegateMethod:@selector(audioPlayer:sustainHDCD:) withObject:[bufferChain userInfo] waitUntilDone:NO];
 }
 
-- (void)setError:(BOOL)status {
-	[self sendDelegateMethod:@selector(audioPlayer:setError:toTrack:) withObject:@(status) withObject:[bufferChain userInfo] waitUntilDone:NO];
+- (void)setError:(BOOL)status forTrack:(id)userInfo {
+	// Buffer chains overlap while tracks are preloaded and switched. Preserve
+	// the chain's own track here; consulting the current global bufferChain when
+	// this asynchronous callback runs can apply a late error to the next track.
+	[self sendDelegateMethod:@selector(audioPlayer:setError:toTrack:) withObject:@(status) withObject:userInfo waitUntilDone:NO];
 }
 
 - (void)setPlaybackStatus:(int)status {

Audio/Chain/BufferChain.m

@@ -314,7 +314,8 @@ - (void)pushInfo:(NSDictionary *)info {
 }
 
 - (void)setError:(BOOL)status {
-	[controller setError:status];
+	AudioPlayer *audioPlayer = controller;
+	[audioPlayer setError:status forTrack:userInfo];
 }
 
 @end

Audio/Chain/InputNode.m

@@ -204,13 +204,10 @@ - (void)process {
 			DLog(@"Seeked! Resetting Buffer");
 			initialBufferFilled = NO;
 
-			if(seekError) {
-				[controller setError:YES];
-			}
-
 			signalReset = YES;
 
 			if([self hasSeekRequestAfterID:activeSeekRequestID]) {
+				seekError = NO;
 				continue;
 			}
 		}
@@ -229,6 +226,11 @@ - (void)process {
 		}
 
 		if(chunk && [chunk frameCount]) {
+			// Some decoders can recover from an inexact or rejected seek and
+			// immediately return valid audio (cue-sheet fragments do this by
+			// seeking to their own start). Do not persist a track error when the
+			// requested playback is still producing audio.
+			seekError = NO;
 			@autoreleasepool {
 				if(signalReset) {
 					chunk.resetForward = YES;
@@ -241,6 +243,11 @@ - (void)process {
 			if([self shouldContinue] == NO) {
 				break;
 			}
+			if(seekError) {
+				ALog(@"Decoder seek failed and produced no audio");
+				[controller setError:YES];
+				seekError = NO;
+			}
 			if(chunk) {
 				@autoreleasepool {
 					chunk = nil;