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 104 matching lines @@
     ScopedComPtr<IEnumMoniker> enum_moniker;
     hr = dev_enum->CreateClassEnumerator(
         kDirectShowFilterClasses[class_index].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)
       continue;
 
-    // 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();
         continue;
       }
 
       // 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) {

[mcasas, 2014/09/04 13:31:17]

Since you are cleaning up around here, suggest changing l.143 and l.151-154 to
invert the comparison and call continue instead:

l.143:

if (FAILED(hr) || name.type() != VT_BSTR)
  continue;

etc.

WDYT?

[magjed_chromium, 2014/09/04 15:31:28]

I agree.

         // 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 ((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 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)) {
+          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,
               kDirectShowFilterClasses[class_index].capture_api_type));
         }
       }
@@ skipping 246 matching lines @@
     const Name& device,
     VideoCaptureFormats* formats) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (use_media_foundation_)
     GetDeviceSupportedFormatsMediaFoundation(device, formats);
   else
     GetDeviceSupportedFormatsDirectShow(device, formats);
 }
 
 }  // namespace media