[Sumover-dev] [svn commit] r3880 - vic/trunk/video

[sumover-dev at cs.ucl.ac.uk]

Author: piers
Date: Thu Sep 21 14:07:53 2006
New Revision: 3880

Modified:
   vic/trunk/video/grabber-win32DS.cpp

Log:
Fixed crash on vic startup due to lack of proper error handling in DirectShowScanner::DirectShowScanner(). This crash only seemed to occur when there are no DS video capture devices present.

Modified: vic/trunk/video/grabber-win32DS.cpp
==============================================================================
--- vic/trunk/video/grabber-win32DS.cpp	(original)
+++ vic/trunk/video/grabber-win32DS.cpp	Thu Sep 21 14:07:53 2006
@@ -736,10 +736,19 @@
    debug_msg("new DirectShowScanner()\n");
 
    // Initialize the COM subsystem
-   CoInitialize(NULL);
+   hr=CoInitialize(NULL);
+   if (FAILED(hr)) {
+	   debug_msg("Failed COM subsystem initialisation.\n");
+	   	return;
+   }
 
-   // Create a helper object to find the capture device.
+   // Create a helper object to find the capture devices.
    hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (LPVOID*)&pDevEnum);
+   if (FAILED(hr)) {
+   		debug_msg("Failed to Create a helper object to find the DS capture devices.\n");
+		CoUninitialize();
+		return;
+   }
 
    IEnumMoniker *pEnum    = 0;
    IMoniker     *pMoniker = 0;
@@ -749,35 +758,52 @@
    // Get an enumerator over video capture filters
    hr = pDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEnum, 0);
    //showErrorMessage(hr);
+   if (FAILED(hr) || pEnum == 0) {
+   		debug_msg("Failed to Get an enumerator over DS video capture filters.\n");
+		CoUninitialize();
+		return;
+   }
 
    // Get the capture filter for each device installed, up to NUM_DEVS devices
    for( devNum=0; devNum < NUM_DEVS; ++devNum) {
       if ( pEnum->Next(1, &pMoniker, NULL) == S_OK ) {
 
          hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pPropBag);
+	     if (FAILED(hr)) {
+			debug_msg("Failed to Get propbag bound to storage on DS dev: %d\n", devNum);
+			continue;
+		 }
          //showErrorMessage(hr);
-         //debug_msg("propbag bound to storage ok= %d\n", hr);
+         debug_msg("propbag bound to storage ok= %d\n", hr);
 
          VariantInit(&varName);
          hr = pPropBag->Read(L"FriendlyName", &varName, 0);
+		 if (FAILED(hr)) {
+			debug_msg("Failed to Get friendly name read on DS dev: %d\n", devNum);
+			continue;
+		 }
          //showErrorMessage(hr);
-         //debug_msg("friendly name read ok= %d\n", hr);
+         debug_msg("friendly name read ok= %d\n", hr);
 
          // Need this macro in atlconv.h to go from bStr to char* - msp
          USES_CONVERSION;
          strcpy(nameBuf, W2A(varName.bstrVal));
 
-         //debug_msg("DirectShowScanner::DirectShowScanner():  found nameBuf/FriendlyName=%s\n", nameBuf);
+         debug_msg("DirectShowScanner::DirectShowScanner():  found nameBuf/FriendlyName=%s\n", nameBuf);
 
          // needs work, but don't add drivers that look like VFW drivers - msp
          if( (strstr(nameBuf, "VFW") == NULL) ) {
             hr = pMoniker->BindToObject(0, 0, IID_IBaseFilter, (void **)(pCaptureFilter+devNum));
             //showErrorMessage(hr);
-
-            //debug_msg("capture filter bound ok= %d\n", hr);
+			if (FAILED(hr)) {
+				debug_msg("Failed to Get friendly name read on DS dev: %d\n", devNum);
+				continue;
+			}
+			debug_msg("capture filter bound ok= %d\n", hr);
             devs_[devNum] = new DirectShowDevice(strdup(nameBuf), pCaptureFilter[devNum]);
          } else {
             debug_msg("discarding an apparent VFW device= %s\n", nameBuf);
+			devs_[devNum] = NULL;
          }
 
          VariantClear(&varName);
@@ -795,5 +821,6 @@
 
 DirectShowScanner::~DirectShowScanner() {
    // This should be printed only when the app exits - msp
+   CoUninitialize();
    debug_msg("~DirectShowScanner()\n");
 }