Effects Pepper Plugin and MediaStream Glue.

content/renderer/media/video_source_handler.h

+// Copyright (c) 2013 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 CONTENT_RENDERER_MEDIA_VIDEO_SOURCE_HANDLER_H_
+#define CONTENT_RENDERER_MEDIA_VIDEO_SOURCE_HANDLER_H_
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
+#include "content/common/content_export.h"
+#include "content/renderer/media/media_stream_registry_interface.h"
+#include "third_party/libjingle/source/talk/app/webrtc/videosourceinterface.h"
+#include "third_party/libjingle/source/talk/media/base/videoframe.h"
+#include "third_party/libjingle/source/talk/media/base/videorenderer.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebMediaStream.h"
+
+namespace content {
+
+class MediaStreamDependencyFactory;
+class MediaStreamRegistryInterface;
+
+// Interface used by the effects pepper plugin to get captured frame
+// from the video track.
+class CONTENT_EXPORT FrameReaderInterface {
+ public:
+  // Gets the last captured frame.
+  // The ownership of the |frame| transfers to the caller. So the caller must
+  // release |frame| when done with it.
+  virtual bool GetFrame(cricket::VideoFrame** frame) = 0;
+
+ protected:
+  virtual ~FrameReaderInterface() {}
+};
+
+// PpFrameReader implements cricket::VideoRenderer so that it can be attached
+// to native video track's video source. It also implements
+// FrameReaderInterface, which will be used by the effects pepper plugin to
+// get the captured frame.
+class CONTENT_EXPORT PpFrameReader
+    : public NON_EXPORTED_BASE(cricket::VideoRenderer),
+      public FrameReaderInterface {
+ public:
+  PpFrameReader();
+  virtual ~PpFrameReader();
+
+  // Implements VideoRenderer.
+  virtual bool SetSize(int width, int height, int reserved) OVERRIDE;
+  virtual bool RenderFrame(const cricket::VideoFrame* frame) OVERRIDE;
+
+  // Implements FrameReaderInterface.
+  virtual bool GetFrame(cricket::VideoFrame** frame) OVERRIDE;
+
+ private:
+  scoped_ptr<cricket::VideoFrame> last_frame_;
+  base::Lock lock_;
+};
+
+// VideoSourceHandler is a glue class between the webrtc MediaStream and
+// the effects pepper plugin host.
+class CONTENT_EXPORT VideoSourceHandler {
+ public:
+  VideoSourceHandler(MediaStreamDependencyFactory* factory,
+                     MediaStreamRegistryInterface* registry);
+  // Connects to the first video track in the MediaStream specified by |url| and
+  // outputs a handler as |frame_reader| for receiving captured frames.
+  // Returns true on success and false on failure.
+  bool Open(const std::string& url, FrameReaderInterface** frame_reader);
+  // Closes |frame_reader|'s connection with the first video track in
+  // the MediaStream specified by |url|, i.e. stops receiving frames from the
+  // video track.
+  // Returns true on success and false on failure.
+  bool Close(const std::string& url, FrameReaderInterface* frame_reader);
+
+ private:
+  scoped_refptr<webrtc::VideoSourceInterface> GetFirstVideoSource(
+      const std::string& url);
+
+  MediaStreamDependencyFactory* factory_;
+  MediaStreamRegistryInterface* registry_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_VIDEO_SOURCE_HANDLER_H_
+