Fix if-statement in win video capture that ignores fake DirectShow filters

media/video/capture/win/video_capture_device_factory_win.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/video/capture/win/video_capture_device_factory_win.h"
 
 #include <mfapi.h>
 #include <mferror.h>
 
 #include "base/command_line.h"
@@ skipping 92 matching lines @@
   if (FAILED(hr))
     return;
 
   ScopedComPtr<IEnumMoniker> enum_moniker;
   hr = dev_enum->CreateClassEnumerator(class_id, enum_moniker.Receive(), 0);
   // CreateClassEnumerator returns S_FALSE on some Windows OS
   // when no camera exist. Therefore the FAILED macro can't be used.
   if (hr != S_OK)
     return;
 
-  // Name of a fake DirectShow filter that exist on computers with
-  // GTalk installed.
-  static const char kGoogleCameraAdapter[] = "google camera adapter";
-
   // Enumerate all video capture devices.
   ScopedComPtr<IMoniker> moniker;
   int index = 0;
   while (enum_moniker->Next(1, moniker.Receive(), NULL) == S_OK) {
     ScopedComPtr<IPropertyBag> prop_bag;
     hr = moniker->BindToStorage(0, 0, IID_IPropertyBag, prop_bag.ReceiveVoid());
     if (FAILED(hr)) {
       moniker.Release();
       return;
     }
 
     // Find the description or friendly name.
     ScopedVariant name;
     hr = prop_bag->Read(L"Description", name.Receive(), 0);
     if (FAILED(hr))
       hr = prop_bag->Read(L"FriendlyName", name.Receive(), 0);
 
-    if (SUCCEEDED(hr) && name.type() == VT_BSTR) {
-      // Ignore all VFW drivers and the special Google Camera Adapter.
-      // Google Camera Adapter is not a real DirectShow camera device.
-      // VFW are very old Video for Windows drivers that can not be used.
-      const wchar_t* str_ptr = V_BSTR(&name);
-      const int name_length = arraysize(kGoogleCameraAdapter) - 1;
+    if (FAILED(hr) || name.type() != VT_BSTR)
+      continue;

[mcasas, 2014/09/04 16:31:12]

Missing moniker.Release();

 
-      if ((wcsstr(str_ptr, L"(VFW)") == NULL) &&
-          lstrlenW(str_ptr) < name_length ||
-          (!(LowerCaseEqualsASCII(str_ptr, str_ptr + name_length,
-                                  kGoogleCameraAdapter)))) {
-        std::string id;
-        std::string device_name(base::SysWideToUTF8(str_ptr));
-        name.Reset();
-        hr = prop_bag->Read(L"DevicePath", name.Receive(), 0);
-        if (FAILED(hr) || name.type() != VT_BSTR) {
-          id = device_name;
-        } else {
-          DCHECK_EQ(name.type(), VT_BSTR);
-          id = base::SysWideToUTF8(V_BSTR(&name));
-        }
-        device_names->push_back(Name(device_name, id, capture_api_type));
-      }
+    // Ignore all VFW drivers and the special Google Camera Adapter.
+    // Google Camera Adapter is not a real DirectShow camera device.
+    // VFW are very old Video for Windows drivers that can not be used.
+    const wchar_t* str_ptr = V_BSTR(&name);
+    // Name of a fake DirectShow filter that exist on computers with
+    // GTalk installed.
+    static const char kGoogleCameraAdapter[] = "google camera adapter";
+    if (wcsstr(str_ptr, L"(VFW)") != NULL ||
+        LowerCaseEqualsASCII(str_ptr,
+                             str_ptr + arraysize(kGoogleCameraAdapter) - 1,
+                             kGoogleCameraAdapter)) {
+      continue;

[mcasas, 2014/09/04 16:31:12]

missing moniker.Release();

     }
-    moniker.Release();
+
+    const std::string device_name(base::SysWideToUTF8(str_ptr));
+    name.Reset();
+    hr = prop_bag->Read(L"DevicePath", name.Receive(), 0);
+    std::string id;
+    if (FAILED(hr) || name.type() != VT_BSTR) {
+      id = device_name;
+    } else {
+      DCHECK_EQ(name.type(), VT_BSTR);
+      id = base::SysWideToUTF8(V_BSTR(&name));
+    }
+    device_names->push_back(Name(device_name, id, capture_api_type));
   }
+
+  moniker.Release();

[mcasas, 2014/09/04 16:31:12]

With so many moniker.Release();, is getting too verbose. 
I propose substituting the use of |moniker| with a local
version, so the while loop would look like:

while (enum_moniker->Next(1, moniker.Receive(), NULL) == S_OK) {
  ScopedComPtr<IMoniker> moniker_local;
  moniker_local.swap(moniker);
  // ... etc

and then use |moniker_local| in the loop and remove all
the Release() calls which would happen automatically.

 }
 
 static void GetDeviceNamesMediaFoundation(Names* device_names) {
   DVLOG(1) << " GetDeviceNamesMediaFoundation";
   ScopedCoMem<IMFActivate*> devices;
   UINT32 count;
   if (!EnumerateVideoDevicesMediaFoundation(&devices, &count))
     return;
 
   for (UINT32 i = 0; i < count; ++i) {
@@ skipping 263 matching lines @@
     const Name& device,
     VideoCaptureFormats* formats) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (use_media_foundation_)
     GetDeviceSupportedFormatsMediaFoundation(device, formats);
   else
     GetDeviceSupportedFormatsDirectShow(device, formats);
 }
 
 }  // namespace media