[PPAPI] Implement media stream video track API

ppapi/proxy/video_frame_resource.h

+// 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.
+
+#ifndef PPAPI_PROXY_VIDEO_FRAME_RESOURCE_H_
+#define PPAPI_PROXY_VIDEO_FRAME_RESOURCE_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "ppapi/proxy/ppapi_proxy_export.h"
+#include "ppapi/shared_impl/media_stream_frame.h"
+#include "ppapi/shared_impl/resource.h"
+#include "ppapi/thunk/ppb_video_frame_api.h"
+
+namespace ppapi {
+namespace proxy {
+
+class PPAPI_PROXY_EXPORT VideoFrameResource : public Resource,
+                                              public thunk::PPB_VideoFrame_API {
+ public:
+  VideoFrameResource(PP_Instance instance,
+                     int32_t index,
+                     MediaStreamFrame::Video* frame);
+  virtual ~VideoFrameResource();
+
+  int32_t index() const { return index_; }
+
+  MediaStreamFrame::Video* video_frame() const { return frame_; }
+
+  void invalidate() {
+    frame_ = NULL;
+    index_ = -1;
+  }

[bbudge, 2014/01/13 20:03:52]

Sorry if I wasn't very clear before. I was thinking that you could make these
methods part of the PPB_VideoFrame_API. Thunk APIs can contain stuff that is
only needed by internal proxy code - they don't have to be in 1:1 correspondence
with the Pepper interface.

If you don't want to do that, then I would prefer that these be private, with
the video track class being a friend. Like you had before.

[Peng, 2014/01/13 20:26:55]

Oops! I misunderstood your comment.

I would like the constructor can only be accessed by
MediaStreamVideoTrackResource as well. I think it can not be added into
PPB_VideoFrame_API, so probably using friend class is better. Change it back.
Done.


On 2014/01/13 20:03:52, bbudge wrote:

[bbudge, 2014/01/13 20:52:44]

Is it that important that the constructor be private? I realize that you only
want these to be created by the MediaStreamVideoTrackResource class, but I don't
think it would be a hazard for anyone working on proxy code if the constructor
was public. Maybe I'm missing something though.

The reason I'm pushing on this is that we already have a way to express what the
internal API for a resource class is - by defining one of these APIs. This would
be the first case in ppapi/proxy where 'friend' is used to give a resource
access into another resource. All other usages of 'friend' in resources are
either for ref counting or test code. There are several cases of classes
interacting through the API interface classes, e.g. FileIOResource and
FileSystemResource.

It does add another file to your patch but I think adding these methods to
PPB_VideoFrame_API will make the code more like the rest of the proxy and so a
little easier to understand.

[Peng, 2014/01/14 15:55:55]

Done. 

+
+
+  // PluginResource overrides:
+  virtual thunk::PPB_VideoFrame_API* AsPPB_VideoFrame_API() OVERRIDE;
+
+  // PPB_VideoFrame_API overrides:
+  virtual PP_TimeDelta GetTimestamp() OVERRIDE;
+  virtual void SetTimestamp(PP_TimeDelta timestamp) OVERRIDE;
+  virtual PP_VideoFrame_Format GetFormat() OVERRIDE;
+  virtual PP_Bool GetSize(PP_Size* size) OVERRIDE;
+  virtual void* GetDataBuffer() OVERRIDE;
+  virtual uint32_t GetDataBufferSize() OVERRIDE;
+
+ private:
+  // Frame index
+  int32_t index_;
+
+  MediaStreamFrame::Video* frame_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoFrameResource);
+};
+
+}  // namespace proxy
+}  // namespace ppapi
+
+#endif  // PPAPI_PROXY_VIDEO_FRAME_RESOURCE_H_