root/content/renderer/media/video_source_handler.cc

DEFINITIONS

1. SetSize
2. RenderFrame
3. SetReader
4. Open
5. Close
6. GetFirstVideoSource
7. GetReceiver
8. source_

// 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.

#include "content/renderer/media/video_source_handler.h"

#include <string>

#include "base/logging.h"
#include "content/renderer/media/media_stream.h"
#include "content/renderer/media/media_stream_dependency_factory.h"
#include "content/renderer/media/media_stream_registry_interface.h"
#include "content/renderer/render_thread_impl.h"
#include "third_party/WebKit/public/platform/WebMediaStream.h"
#include "third_party/WebKit/public/platform/WebURL.h"
#include "third_party/WebKit/public/web/WebMediaStreamRegistry.h"
#include "third_party/libjingle/source/talk/media/base/videoframe.h"
#include "third_party/libjingle/source/talk/media/base/videorenderer.h"
#include "url/gurl.h"

using cricket::VideoFrame;
using cricket::VideoRenderer;
using webrtc::VideoSourceInterface;

namespace content {

// PpFrameReceiver implements cricket::VideoRenderer so that it can be attached
// to native video track's video source to receive the captured frame.
// It can be attached to a FrameReaderInterface to output the received frame.
class PpFrameReceiver : public cricket::VideoRenderer {
 public:
  PpFrameReceiver() : reader_(NULL) {}
  virtual ~PpFrameReceiver() {}

  // Implements VideoRenderer.
  virtual bool SetSize(int width, int height, int reserved) OVERRIDE {
    return true;
  }
  virtual bool RenderFrame(const cricket::VideoFrame* frame) OVERRIDE {
    base::AutoLock auto_lock(lock_);
    if (reader_) {
      // |frame| will be invalid after this function is returned. So keep a copy
      // before return.
      cricket::VideoFrame* copied_frame = frame->Copy();
      copied_frame->MakeExclusive();
      reader_->GotFrame(copied_frame);
    }
    return true;
  }

  void SetReader(FrameReaderInterface* reader) {
    base::AutoLock auto_lock(lock_);
    reader_ = reader;
  }

 private:
  FrameReaderInterface* reader_;
  base::Lock lock_;

  DISALLOW_COPY_AND_ASSIGN(PpFrameReceiver);
};

VideoSourceHandler::VideoSourceHandler(
    MediaStreamRegistryInterface* registry)
    : registry_(registry) {
}

VideoSourceHandler::~VideoSourceHandler() {
  for (SourceInfoMap::iterator it = reader_to_receiver_.begin();
       it != reader_to_receiver_.end();
       ++it) {
    delete it->second;
  }
}

bool VideoSourceHandler::Open(const std::string& url,
                              FrameReaderInterface* reader) {
  scoped_refptr<webrtc::VideoSourceInterface> source = GetFirstVideoSource(url);
  if (!source.get()) {
    return false;
  }
  reader_to_receiver_[reader] = new SourceInfo(source, reader);
  return true;
}

bool VideoSourceHandler::Close(FrameReaderInterface* reader) {
  SourceInfoMap::iterator it = reader_to_receiver_.find(reader);
  if (it == reader_to_receiver_.end()) {
    return false;
  }
  delete it->second;
  reader_to_receiver_.erase(it);
  return true;
}

scoped_refptr<VideoSourceInterface> VideoSourceHandler::GetFirstVideoSource(
    const std::string& url) {
  scoped_refptr<webrtc::VideoSourceInterface> source;
  blink::WebMediaStream stream;
  if (registry_) {
    stream = registry_->GetMediaStream(url);
  } else {
    stream =
        blink::WebMediaStreamRegistry::lookupMediaStreamDescriptor(GURL(url));
  }
  if (stream.isNull() || !stream.extraData()) {
    LOG(ERROR) << "GetFirstVideoSource - invalid url: " << url;
    return source;
  }

  // Get the first video track from the stream.
  webrtc::MediaStreamInterface* native_stream = MediaStream::GetAdapter(stream);
  webrtc::VideoTrackVector native_video_tracks =
      native_stream->GetVideoTracks();
  if (native_video_tracks.empty()) {
    LOG(ERROR) << "GetFirstVideoSource - stream has no video track.";
    return source;
  }
  source = native_video_tracks[0]->GetSource();
  return source;
}

VideoRenderer* VideoSourceHandler::GetReceiver(
    FrameReaderInterface* reader) {
  SourceInfoMap::iterator it = reader_to_receiver_.find(reader);
  if (it == reader_to_receiver_.end()) {
    return NULL;
  }
  return it->second->receiver_.get();
}

VideoSourceHandler::SourceInfo::SourceInfo(
    scoped_refptr<webrtc::VideoSourceInterface> source,
    FrameReaderInterface* reader)
    : receiver_(new PpFrameReceiver()),
      source_(source) {
  source_->AddSink(receiver_.get());
  receiver_->SetReader(reader);
}

VideoSourceHandler::SourceInfo::~SourceInfo() {
  source_->RemoveSink(receiver_.get());
  receiver_->SetReader(NULL);
}

}  // namespace content