Remove reference counting from media::Demuxer and friends.

media/filters/ffmpeg_demuxer.cc

 // Copyright (c) 2012 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/filters/ffmpeg_demuxer.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/base64.h"
@@ skipping 254 matching lines @@
 
 //
 // FFmpegDemuxer
 //
 FFmpegDemuxer::FFmpegDemuxer(
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     const scoped_refptr<DataSource>& data_source,
     const FFmpegNeedKeyCB& need_key_cb)
     : host_(NULL),
       message_loop_(message_loop),
+      weak_factory_(this),
       blocking_thread_("FFmpegDemuxer"),
       pending_read_(false),
       pending_seek_(false),
       data_source_(data_source),
       bitrate_(0),
       start_time_(kNoTimestamp()),
       audio_disabled_(false),
       duration_known_(false),
       url_protocol_(data_source, BindToLoop(message_loop_, base::Bind(
           &FFmpegDemuxer::OnDataSourceError, base::Unretained(this)))),
       need_key_cb_(need_key_cb) {
   DCHECK(message_loop_);
   DCHECK(data_source_);
 }
 
 FFmpegDemuxer::~FFmpegDemuxer() {}
 
 void FFmpegDemuxer::Stop(const base::Closure& callback) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   url_protocol_.Abort();
   data_source_->Stop(BindToCurrentLoop(base::Bind(
-      &FFmpegDemuxer::OnDataSourceStopped, this, BindToCurrentLoop(callback))));
+      &FFmpegDemuxer::OnDataSourceStopped, weak_this_,
+      BindToCurrentLoop(callback))));
 }
 
 void FFmpegDemuxer::Seek(base::TimeDelta time, const PipelineStatusCB& cb) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   CHECK(!pending_seek_);
 
   // TODO(scherkus): Inspect |pending_read_| and cancel IO via |blocking_url_|,
   // otherwise we can end up waiting for a pre-seek read to complete even though
   // we know we're going to drop it on the floor.
 
   // Always seek to a timestamp less than or equal to the desired timestamp.
   int flags = AVSEEK_FLAG_BACKWARD;
 
   // Passing -1 as our stream index lets FFmpeg pick a default stream.  FFmpeg
   // will attempt to use the lowest-index video stream, if present, followed by
   // the lowest-index audio stream.
   pending_seek_ = true;
   base::PostTaskAndReplyWithResult(
       blocking_thread_.message_loop_proxy(), FROM_HERE,
       base::Bind(&av_seek_frame, glue_->format_context(), -1,
                  time.InMicroseconds(), flags),
-      base::Bind(&FFmpegDemuxer::OnSeekFrameDone, this, cb));
+      base::Bind(&FFmpegDemuxer::OnSeekFrameDone, weak_this_, cb));
 }
 
 void FFmpegDemuxer::SetPlaybackRate(float playback_rate) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   data_source_->SetPlaybackRate(playback_rate);
 }
 
 void FFmpegDemuxer::OnAudioRendererDisabled() {
   DCHECK(message_loop_->BelongsToCurrentThread());
   audio_disabled_ = true;
   StreamVector::iterator iter;
   for (iter = streams_.begin(); iter != streams_.end(); ++iter) {
     if (*iter && (*iter)->type() == DemuxerStream::AUDIO) {
       (*iter)->Stop();
     }
   }
 }
 
 void FFmpegDemuxer::Initialize(DemuxerHost* host,
                                const PipelineStatusCB& status_cb) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   host_ = host;
+  weak_this_ = weak_factory_.GetWeakPtr();

[acolwell GONE FROM CHROMIUM, 2013/04/17 20:24:53]

nit: Why is this deferred until here? Why not do this in the constructor?

Can Stop() get called before Initialize()?

[scherkus (not reviewing), 2013/04/19 01:07:22]

WeakPtr binds to thread it's created on.

Since we create objects on the render thread but want them bound to the media
thread we defer assigning weak_this_ until Initialize().

 
   // TODO(scherkus): DataSource should have a host by this point,
   // see http://crbug.com/122071
   data_source_->set_host(host);
 
   glue_.reset(new FFmpegGlue(&url_protocol_));
   AVFormatContext* format_context = glue_->format_context();
 
   // Disable ID3v1 tag reading to avoid costly seeks to end of file for data we
   // don't use.  FFmpeg will only read ID3v1 tags if no other metadata is
   // available, so add a metadata entry to ensure some is always present.
   av_dict_set(&format_context->metadata, "skip_id3v1_tags", "", 0);
 
   // Open the AVFormatContext using our glue layer.
   CHECK(blocking_thread_.Start());
   base::PostTaskAndReplyWithResult(
       blocking_thread_.message_loop_proxy(), FROM_HERE,
       base::Bind(&FFmpegGlue::OpenContext, base::Unretained(glue_.get())),
-      base::Bind(&FFmpegDemuxer::OnOpenContextDone, this, status_cb));
+      base::Bind(&FFmpegDemuxer::OnOpenContextDone, weak_this_, status_cb));
 }
 
-scoped_refptr<DemuxerStream> FFmpegDemuxer::GetStream(
-    DemuxerStream::Type type) {
+DemuxerStream* FFmpegDemuxer::GetStream(DemuxerStream::Type type) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   return GetFFmpegStream(type);
 }
 
-scoped_refptr<FFmpegDemuxerStream> FFmpegDemuxer::GetFFmpegStream(
+FFmpegDemuxerStream* FFmpegDemuxer::GetFFmpegStream(
     DemuxerStream::Type type) const {
   StreamVector::const_iterator iter;
   for (iter = streams_.begin(); iter != streams_.end(); ++iter) {
     if (*iter && (*iter)->type() == type) {
       return *iter;
     }
   }
   return NULL;
 }
 
@@ skipping 49 matching lines @@
   if (!result) {
     status_cb.Run(DEMUXER_ERROR_COULD_NOT_OPEN);
     return;
   }
 
   // Fully initialize AVFormatContext by parsing the stream a little.
   base::PostTaskAndReplyWithResult(
       blocking_thread_.message_loop_proxy(), FROM_HERE,
       base::Bind(&avformat_find_stream_info, glue_->format_context(),
                  static_cast<AVDictionary**>(NULL)),
-      base::Bind(&FFmpegDemuxer::OnFindStreamInfoDone, this, status_cb));
+      base::Bind(&FFmpegDemuxer::OnFindStreamInfoDone, weak_this_, status_cb));
 }
 
 void FFmpegDemuxer::OnFindStreamInfoDone(const PipelineStatusCB& status_cb,
                                          int result) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   if (!blocking_thread_.IsRunning()) {
     status_cb.Run(PIPELINE_ERROR_ABORT);
     return;
   }
 
@@ skipping 25 matching lines @@
         continue;
       // Ensure the codec is supported.
       if (CodecIDToVideoCodec(codec_context->codec_id) == kUnknownVideoCodec)
         continue;
       found_video_stream = true;
     } else {
       continue;
     }
 
     AVStream* stream = format_context->streams[i];
-    scoped_refptr<FFmpegDemuxerStream> demuxer_stream(
-        new FFmpegDemuxerStream(this, stream));
-
-    streams_[i] = demuxer_stream;
-    max_duration = std::max(max_duration, demuxer_stream->duration());
+    streams_[i] = new FFmpegDemuxerStream(this, stream);
+    max_duration = std::max(max_duration, streams_[i]->duration());
 
     if (stream->first_dts != static_cast<int64_t>(AV_NOPTS_VALUE)) {
       const base::TimeDelta first_dts = ConvertFromTimeBase(
           stream->time_base, stream->first_dts);
       if (start_time_ == kNoTimestamp() || first_dts < start_time_)
         start_time_ = first_dts;
     }
   }
 
   if (!found_audio_stream && !found_video_stream) {
@@ skipping 80 matching lines @@
   // Allocate and read an AVPacket from the media. Save |packet_ptr| since
   // evaluation order of packet.get() and base::Passed(&packet) is
   // undefined.
   ScopedAVPacket packet(new AVPacket());
   AVPacket* packet_ptr = packet.get();
 
   pending_read_ = true;
   base::PostTaskAndReplyWithResult(
       blocking_thread_.message_loop_proxy(), FROM_HERE,
       base::Bind(&av_read_frame, glue_->format_context(), packet_ptr),
-      base::Bind(&FFmpegDemuxer::OnReadFrameDone, this, base::Passed(&packet)));
+      base::Bind(&FFmpegDemuxer::OnReadFrameDone, weak_this_,
+                 base::Passed(&packet)));
 }
 
 void FFmpegDemuxer::OnReadFrameDone(ScopedAVPacket packet, int result) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK(pending_read_);
   pending_read_ = false;
 
   if (!blocking_thread_.IsRunning() || pending_seek_) {
     return;
   }
@@ skipping 109 matching lines @@
 }
 
 void FFmpegDemuxer::NotifyCapacityAvailable() {
   DCHECK(message_loop_->BelongsToCurrentThread());
   ReadFrameIfNeeded();
 }
 
 void FFmpegDemuxer::NotifyBufferingChanged() {
   DCHECK(message_loop_->BelongsToCurrentThread());
   Ranges<base::TimeDelta> buffered;
-  scoped_refptr<FFmpegDemuxerStream> audio =
+  FFmpegDemuxerStream* audio =
       audio_disabled_ ? NULL : GetFFmpegStream(DemuxerStream::AUDIO);
-  scoped_refptr<FFmpegDemuxerStream> video =
-      GetFFmpegStream(DemuxerStream::VIDEO);
+  FFmpegDemuxerStream* video = GetFFmpegStream(DemuxerStream::VIDEO);
   if (audio && video) {
     buffered = audio->GetBufferedRanges().IntersectionWith(
         video->GetBufferedRanges());
   } else if (audio) {
     buffered = audio->GetBufferedRanges();
   } else if (video) {
     buffered = video->GetBufferedRanges();
   }
   for (size_t i = 0; i < buffered.size(); ++i)
     host_->AddBufferedTimeRange(buffered.start(i), buffered.end(i));
 }
 
 void FFmpegDemuxer::OnDataSourceError() {
   host_->OnDemuxerError(PIPELINE_ERROR_READ);
 }
 
 }  // namespace media