From 1783abec1351ccd7b101307eb536b0e74e91b014 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Tue, 12 Apr 2016 00:50:59 -0400
Subject: [PATCH] Lock around LiStartConnection() and LiStopConnection() to fix
 thread-safety issues. This will hopefully address the crashes seen in 1.0.3
 and 1.0.4.

---
 Limelight/Stream/Connection.h                 |  1 -
 Limelight/Stream/Connection.m                 | 31 +++++++++++--------
 Limelight/Stream/StreamManager.h              |  1 -
 Limelight/Stream/StreamManager.m              |  9 ------
 .../StreamFrameViewController.m               |  4 +--
 5 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/Limelight/Stream/Connection.h b/Limelight/Stream/Connection.h
index a151569..d1eaae1 100644
--- a/Limelight/Stream/Connection.h
+++ b/Limelight/Stream/Connection.h
@@ -27,7 +27,6 @@
 
 -(id) initWithConfig:(StreamConfiguration*)config renderer:(VideoDecoderRenderer*)myRenderer connectionCallbacks:(id<ConnectionCallbacks>)callbacks serverMajorVersion:(int)serverMajorVersion;
 -(void) terminate;
--(void) terminateInternal;
 -(void) main;
 
 @end
diff --git a/Limelight/Stream/Connection.m b/Limelight/Stream/Connection.m
index 3eff486..aeedba9 100644
--- a/Limelight/Stream/Connection.m
+++ b/Limelight/Stream/Connection.m
@@ -23,6 +23,7 @@
     int _serverMajorVersion;
 }
 
+static NSLock* initLock;
 static OpusDecoder *opusDecoder;
 static id<ConnectionCallbacks> _callbacks;
 
@@ -261,26 +262,28 @@ void ClDisplayTransientMessage(char* message)
     [_callbacks displayTransientMessage: message];
 }
 
--(void) terminateInternal
-{
-    // We dispatch this async to get out because this can be invoked
-    // on a thread inside common and we don't want to deadlock
-    dispatch_async(dispatch_get_main_queue(), ^{
-        // This is safe to call even before LiStartConnection
-        LiStopConnection();
-    });
-}
-
 -(void) terminate
 {
-    // We're guaranteed to not be on a moonlight-common thread
-    // here so it's safe to call stop directly
-    LiStopConnection();
+    // We dispatch this async to get out because this can be invoked
+    // on a thread inside common and we don't want to deadlock. It also avoids
+    // blocking on the caller's thread waiting to acquire initLock.
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
+        [initLock lock];
+        LiStopConnection();
+        [initLock unlock];
+    });
 }
 
 -(id) initWithConfig:(StreamConfiguration*)config renderer:(VideoDecoderRenderer*)myRenderer connectionCallbacks:(id<ConnectionCallbacks>)callbacks serverMajorVersion:(int)serverMajorVersion
 {
     self = [super init];
+    
+    // Use a lock to ensure that only one thread is initializing
+    // or deinitializing a connection at a time.
+    if (initLock == nil) {
+        initLock = [[NSLock alloc] init];
+    }
+    
     _host = [config.host cStringUsingEncoding:NSUTF8StringEncoding];
     renderer = myRenderer;
     _callbacks = callbacks;
@@ -403,12 +406,14 @@ static OSStatus playbackCallback(void *inRefCon,
 
 -(void) main
 {
+    [initLock lock];
     LiStartConnection(_host,
                       &_streamConfig,
                       &_clCallbacks,
                       &_drCallbacks,
                       &_arCallbacks,
                       NULL, 0, _serverMajorVersion);
+    [initLock unlock];
 }
 
 @end
diff --git a/Limelight/Stream/StreamManager.h b/Limelight/Stream/StreamManager.h
index 44c45ad..b2285e1 100644
--- a/Limelight/Stream/StreamManager.h
+++ b/Limelight/Stream/StreamManager.h
@@ -14,6 +14,5 @@
 
 - (id) initWithConfig:(StreamConfiguration*)config renderView:(UIView*)view connectionCallbacks:(id<ConnectionCallbacks>)callback;
 - (void) stopStream;
-- (void) stopStreamInternal;
 
 @end
diff --git a/Limelight/Stream/StreamManager.m b/Limelight/Stream/StreamManager.m
index 335b433..841015c 100644
--- a/Limelight/Stream/StreamManager.m
+++ b/Limelight/Stream/StreamManager.m
@@ -91,20 +91,11 @@
     [opQueue addOperation:_connection];
 }
 
-// This should NEVER be called from within a thread
-// owned by moonlight-common
 - (void) stopStream
 {
     [_connection terminate];
 }
 
-// This should only be called from within a thread
-// owned by moonlight-common
-- (void) stopStreamInternal
-{
-    [_connection terminateInternal];
-}
-
 - (BOOL) launchApp:(HttpManager*)hMan {
     HttpResponse* launchResp = [[HttpResponse alloc] init];
     [hMan executeRequestSynchronously:[HttpRequest requestForResponse:launchResp withUrlRequest:
diff --git a/Limelight/ViewControllers/StreamFrameViewController.m b/Limelight/ViewControllers/StreamFrameViewController.m
index 5b5b796..c871a89 100644
--- a/Limelight/ViewControllers/StreamFrameViewController.m
+++ b/Limelight/ViewControllers/StreamFrameViewController.m
@@ -84,7 +84,7 @@
         [self presentViewController:conTermAlert animated:YES completion:nil];
     });
 
-    [_streamMan stopStreamInternal];
+    [_streamMan stopStream];
 }
 
 - (void) stageStarting:(char*)stageName {
@@ -115,7 +115,7 @@
         [self presentViewController:alert animated:YES completion:nil];
     });
     
-    [_streamMan stopStreamInternal];
+    [_streamMan stopStream];
 }
 
 - (void) launchFailed:(NSString*)message {