From d563617998fac780e4804fa091251ca55c857d4f Mon Sep 17 00:00:00 2001
From: Christopher Snowhill <kode54@gmail.com>
Date: Fri, 24 Jun 2022 19:14:48 -0700
Subject: [PATCH] [Audio Output] Stop immediately, and fix deadlocks

Stop output when requested, except on natural completion of the last
track in the play queue. Also fix deadlocks with stopping and
restarting.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>
---
 Audio/AudioPlayer.m               | 10 +++++---
 Audio/Chain/OutputNode.m          |  4 +++
 Audio/Output/OutputAVFoundation.h |  2 ++
 Audio/Output/OutputAVFoundation.m | 41 +++++++++++++++++++------------
 4 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/Audio/AudioPlayer.m b/Audio/AudioPlayer.m
index c6ea5d61d..c720bf783 100644
--- a/Audio/AudioPlayer.m
+++ b/Audio/AudioPlayer.m
@@ -62,9 +62,10 @@
 	[self waitUntilCallbacksExit];
 	if(output) {
 		[output setShouldContinue:NO];
-		output = nil;
 	}
-	output = [[OutputNode alloc] initWithController:self previous:nil];
+	if(!output) {
+		output = [[OutputNode alloc] initWithController:self previous:nil];
+	}
 	[output setup];
 	[output setVolume:volume];
 	@synchronized(chainQueue) {
@@ -133,6 +134,9 @@
 			bufferChain = nil;
 		}
 	}
+	if(output) {
+		[output setShouldContinue:NO];
+	}
 	output = nil;
 }
 
@@ -278,7 +282,7 @@
 }
 
 - (void)endEqualizer:(AudioUnit)eq {
-	[self sendDelegateMethod:@selector(audioPlayer:removeEqualizer:) withVoid:eq waitUntilDone:YES];
+	[self sendDelegateMethod:@selector(audioPlayer:removeEqualizer:) withVoid:eq waitUntilDone:NO];
 }
 
 - (void)addChainToQueue:(BufferChain *)newChain {
diff --git a/Audio/Chain/OutputNode.m b/Audio/Chain/OutputNode.m
index dc128bb8f..c03d82d32 100644
--- a/Audio/Chain/OutputNode.m
+++ b/Audio/Chain/OutputNode.m
@@ -156,6 +156,10 @@
 }
 
 - (void)setShouldContinue:(BOOL)s {
+	if(output && !s) {
+		[output stop];
+	}
+
 	[super setShouldContinue:s];
 
 	//	if (s == NO)
diff --git a/Audio/Output/OutputAVFoundation.h b/Audio/Output/OutputAVFoundation.h
index fc042da4c..8f1552213 100644
--- a/Audio/Output/OutputAVFoundation.h
+++ b/Audio/Output/OutputAVFoundation.h
@@ -43,6 +43,7 @@ using std::atomic_long;
 	double lastVisRate;
 
 	BOOL stopInvoked;
+	BOOL stopCompleted;
 	BOOL running;
 	BOOL stopping;
 	BOOL stopped;
@@ -50,6 +51,7 @@ using std::atomic_long;
 	BOOL paused;
 	BOOL restarted;
 	BOOL stopFlush;
+	BOOL commandStop;
 
 	BOOL eqEnabled;
 	BOOL eqInitialized;
diff --git a/Audio/Output/OutputAVFoundation.m b/Audio/Output/OutputAVFoundation.m
index d3c7c67e8..2790aaf10 100644
--- a/Audio/Output/OutputAVFoundation.m
+++ b/Audio/Output/OutputAVFoundation.m
@@ -212,20 +212,16 @@ static OSStatus eqRenderCallback(void *inRefCon, AudioUnitRenderActionFlags *ioA
 		return 0;
 	}
 
+	if(stopping) return 0;
+
 	float volumeScale = 1.0;
 	double sustained;
-	@synchronized(self) {
-		sustained = secondsHdcdSustained;
-	}
+	sustained = secondsHdcdSustained;
 	if(sustained > 0) {
 		if(sustained < amountRead) {
-			@synchronized(self) {
-				secondsHdcdSustained = 0;
-			}
+			secondsHdcdSustained = 0;
 		} else {
-			@synchronized(self) {
-				secondsHdcdSustained -= chunkDuration;
-			}
+			secondsHdcdSustained -= chunkDuration;
 			volumeScale = 0.5;
 		}
 	}
@@ -315,9 +311,8 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 }
 
 - (BOOL)processEndOfStream {
-	if([outputController endOfStream] == YES && [self signalEndOfStream:secondsLatency]) {
+	if(stopping || ([outputController endOfStream] == YES && [self signalEndOfStream:secondsLatency])) {
 		stopping = YES;
-		stopFlush = YES;
 		return YES;
 	}
 	return NO;
@@ -378,7 +373,7 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 
 	stopped = YES;
 	if(!stopInvoked) {
-		[self stop];
+		[self doStop];
 	}
 }
 
@@ -803,6 +798,8 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 
 	@synchronized(self) {
 		stopInvoked = NO;
+		stopCompleted = NO;
+		commandStop = NO;
 
 		running = NO;
 		stopping = NO;
@@ -1000,8 +997,21 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 }
 
 - (void)stop {
+	commandStop = YES;
+	[self doStop];
+}
+
+- (void)doStop {
+	if(stopInvoked) {
+		while(!stopCompleted) {
+			usleep(5000);
+		}
+		return;
+	}
 	@synchronized(self) {
-		if(stopInvoked) return;
+		if(commandStop) {
+			stopFlush = NO;
+		}
 		stopInvoked = YES;
 		if(observersapplied) {
 			[[NSUserDefaultsController sharedUserDefaultsController] removeObserver:self forKeyPath:@"values.outputDevice" context:kOutputAVFoundationContext];
@@ -1094,6 +1104,7 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 			r8bstate_delete(r8bvis);
 			r8bvis = NULL;
 		}
+		stopCompleted = YES;
 	}
 }
 
@@ -1114,9 +1125,7 @@ current_device_listener(AudioObjectID inObjectID, UInt32 inNumberAddresses, cons
 }
 
 - (void)sustainHDCD {
-	@synchronized(self) {
-		secondsHdcdSustained = 10.0;
-	}
+	secondsHdcdSustained = 10.0;
 }
 
 @end