[libvidcap-commit] SF.net SVN: libvidcap: [18] trunk/src/directshow

[libvidcap c. m. <lib...@li...>]

Revision: 18
          http://libvidcap.svn.sourceforge.net/libvidcap/?rev=18&view=rev
Author:   bcholew
Date:     2007-09-13 06:05:21 -0700 (Thu, 13 Sep 2007)

Log Message:
-----------
When cancelling capture callbacks, stop() capture before calling final callback. This removes the need for a mutex to protect capture_callback from simultaneous access by cancelCallbacks() and an actual capture callback ( BufferCB() ).

Modified Paths:
--------------
    trunk/src/directshow/DirectShowSource.cpp
    trunk/src/directshow/DirectShowSource.h

Modified: trunk/src/directshow/DirectShowSource.cpp
===================================================================
--- trunk/src/directshow/DirectShowSource.cpp	2007-09-12 18:05:45 UTC (rev 17)
+++ trunk/src/directshow/DirectShowSource.cpp	2007-09-13 13:05:21 UTC (rev 18)
@@ -50,8 +50,7 @@
 	  pSampleGrabberIF_(0),
 	  pNullRenderer_(0),
 	  pMediaControlIF_(0),
-	  nativeMediaType_(0),
-	  stoppingCapture_(false)
+	  nativeMediaType_(0)
 {
 	if ( !dshowMgr_ )
 	{
@@ -146,8 +145,6 @@
 	// FIXME: Is this too early? Should we only do it during captures?
 	dshowMgr_->registerSrcGraph(this, pMediaEventIF_);
 
-	InitializeCriticalSection(&captureMutex_);
-
 	return;
 
 constructionFailure:
@@ -189,8 +186,6 @@
 	pCapGraphBuilder_->Release();
 
 	dshowMgr_->sourceReleased( getID() );
-
-	DeleteCriticalSection(&captureMutex_);
 }
 
 void
@@ -336,10 +331,8 @@
 	pSampleGrabber_->Release();
 	pSampleGrabber_ = 0;
 bail_1:
-	EnterCriticalSection(&captureMutex_);
 	pMediaControlIF_->Release();
 	pMediaControlIF_ = 0;
-	LeaveCriticalSection(&captureMutex_);
 
 	return -1;
 }
@@ -367,10 +360,7 @@
 DirectShowSource::stop()
 {
 	int ret = 0;
-	stoppingCapture_ = true;
 
-	EnterCriticalSection(&captureMutex_);
-
 	if ( pMediaControlIF_ )
 	{
 		HRESULT hr = pMediaControlIF_->Stop();
@@ -382,10 +372,6 @@
 		}
 	}
 
-	LeaveCriticalSection(&captureMutex_);
-
-	stoppingCapture_ = false;
-
 	return ret;
 }
 
@@ -732,23 +718,18 @@
 void
 DirectShowSource::cancelCallbacks()
 {
-	// serialize with normal capture callbacks
-	EnterCriticalSection(&captureMutex_);
-
-	// only cancel callbacks once (unless re-registered)
+	// have capture callbacks already been cancelled?
 	if ( !sourceContext_->capture_callback )
-	{
-		LeaveCriticalSection(&captureMutex_);
 		return;
-	}
 
-	// call capture callback - but let the
+	// stop callbacks BEFORE thinking of
+	// touching sourceContext_->capture_callback
+	stop();
+
+	// call capture callback - but let vidcap and the
 	// app know that this is the last time
+	// (vidcap will reset capture_callback)
 	sapi_src_capture_notify(sourceContext_, 0, 0, -1);
-
-	LeaveCriticalSection(&captureMutex_);
-
-	stop();
 }
 
 STDMETHODIMP
@@ -770,22 +751,12 @@
 STDMETHODIMP
 DirectShowSource::BufferCB( double dblSampleTime, BYTE * pBuff, long buffSize )
 {
-	// prevent deadlock while stopping
-	if ( stoppingCapture_ )
-		return 0;
-
-	EnterCriticalSection(&captureMutex_);
-
 	if ( !sourceContext_->capture_callback )
 		return 0;
 
-	int ret = sapi_src_capture_notify(sourceContext_,
+	return sapi_src_capture_notify(sourceContext_,
 			reinterpret_cast<const char *>(pBuff),
 			static_cast<int>(buffSize), 0);
-
-	LeaveCriticalSection(&captureMutex_);
-
-	return ret;
 }
 
 int

Modified: trunk/src/directshow/DirectShowSource.h
===================================================================
--- trunk/src/directshow/DirectShowSource.h	2007-09-12 18:05:45 UTC (rev 17)
+++ trunk/src/directshow/DirectShowSource.h	2007-09-13 13:05:21 UTC (rev 18)
@@ -96,8 +96,6 @@
 	IBaseFilter * pNullRenderer_;
 	IMediaControl * pMediaControlIF_;
 	AM_MEDIA_TYPE *nativeMediaType_;
-	CRITICAL_SECTION  captureMutex_;
-	bool stoppingCapture_;
 };
 
 #endif


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