Fix potential deadlock in SyphonClient

Problem since eafbc08
Syphon · Sep 28, 2016 · e315503 · e315503
1 parent 206242f
commit e315503
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Showing 2 changed files with 5 additions and 6 deletions.
diff --git a/SyphonClient.h b/SyphonClient.h
@@ -54,7 +54,7 @@
 	int32_t			_lock;
     CGLContextObj   _context;
     SYPHON_IMAGE_UNIQUE_CLASS_NAME *_frame;
-    BOOL            _frameValid;
+    int32_t         _frameValid;
 }
 /*! 
  Returns a new client instance for the described server. You should check the isValid property after initialization to ensure a connection was made to the server.

diff --git a/SyphonClient.m b/SyphonClient.m
@@ -132,12 +132,11 @@ - (void)receiveNewFrame
 
 - (void)invalidateFrame
 {
-    OSSpinLockLock(&_lock);
     /*
      Because releasing a SyphonImage causes a glDelete we postpone deletion until we can do work in the context
+     DO NOT take the lock here, it may already be locked and waiting for the SyphonClientConnectionManager lock
      */
-    _frameValid = NO;
-    OSSpinLockUnlock(&_lock);
+    OSAtomicTestAndClearBarrier(0, &_frameValid);
 }
 
 #pragma mark Rendering frames
@@ -154,11 +153,11 @@ - (SyphonImage *)newFrameImage
 {
 	OSSpinLockLock(&_lock);
 	_lastFrameID = [(SyphonClientConnectionManager *)_connectionManager frameID];
-    if (_frameValid == NO)
+    if (_frameValid == 0)
     {
         [_frame release];
         _frame = [(SyphonClientConnectionManager *)_connectionManager newFrameForContext:_context];
-        _frameValid = YES;
+        OSAtomicTestAndSetBarrier(0, &_frameValid);
     }
 	OSSpinLockUnlock(&_lock);
 	return [_frame retain];