Add Stop() to AudioDecoder.

media/filters/opus_audio_decoder.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/opus_audio_decoder.h"
 
 #include <cmath>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 280 matching lines @@
   }
 
   statistics_cb_ = statistics_cb;
   initialize_cb.Run(PIPELINE_OK);
 }
 
 void OpusAudioDecoder::Read(const ReadCB& read_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!read_cb.is_null());
   CHECK(read_cb_.is_null()) << "Overlapping decodes are not supported.";
+  DCHECK(stop_cb_.is_null());
   read_cb_ = BindToCurrentLoop(read_cb);
 
   ReadFromDemuxerStream();
 }
 
 int OpusAudioDecoder::bits_per_channel() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   return bits_per_channel_;
 }
 
 ChannelLayout OpusAudioDecoder::channel_layout() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   return channel_layout_;
 }
 
 int OpusAudioDecoder::samples_per_second() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   return samples_per_second_;
 }
 
 void OpusAudioDecoder::Reset(const base::Closure& closure) {
   DCHECK(task_runner_->BelongsToCurrentThread());
-  base::Closure reset_cb = BindToCurrentLoop(closure);
+  reset_cb_ = BindToCurrentLoop(closure);

[DaleCurtis, 2014/01/09 23:04:21]

Do we need the BTCL here and below?  Ditto for FFmpegAudioDecoder.  ARI is also
using BTCL, so this is now taking a couple hops.  It'd be better to clarify the
contract in the header file and DCHECK() things are on the right thread.

[rileya (GONE FROM CHROMIUM), 2014/01/10 00:04:05]

I saw Reset using BTCL originally and figured there was a good reason... but I
guess it does look unnecessary. How would you suggest noting this in the header?
I don't completely understand how BTCL works, so I'm a little iffy on how to
explain things...

+
+  if (read_cb_.is_null())
+    DoReset();
+  // Otherwise we have to wait for the pending demuxer read.
+}
+
+void OpusAudioDecoder::Stop(const base::Closure& closure) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  stop_cb_ = BindToCurrentLoop(closure);
+
+  if (read_cb_.is_null())
+    DoStop();
+  // Otherwise we have to wait for the pending demuxer read.
+}
+
+OpusAudioDecoder::~OpusAudioDecoder() {}
+
+void OpusAudioDecoder::DoReset() {
+  DCHECK(!reset_cb_.is_null());
 
   opus_multistream_decoder_ctl(opus_decoder_, OPUS_RESET_STATE);
   ResetTimestampState();
-  reset_cb.Run();
+  base::ResetAndReturn(&reset_cb_).Run();
 }
 
-OpusAudioDecoder::~OpusAudioDecoder() {
-  // TODO(scherkus): should we require Stop() to be called? this might end up
-  // getting called on a random thread due to refcounting.
+void OpusAudioDecoder::DoStop() {
+  DCHECK(!stop_cb_.is_null());
+
+  opus_multistream_decoder_ctl(opus_decoder_, OPUS_RESET_STATE);
+  ResetTimestampState();
   CloseDecoder();
+  base::ResetAndReturn(&stop_cb_).Run();
 }
 
 void OpusAudioDecoder::ReadFromDemuxerStream() {
   DCHECK(!read_cb_.is_null());
   demuxer_stream_->Read(base::Bind(&OpusAudioDecoder::BufferReady, weak_this_));
 }
 
 void OpusAudioDecoder::BufferReady(
     DemuxerStream::Status status,
     const scoped_refptr<DecoderBuffer>& input) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!read_cb_.is_null());
   DCHECK_EQ(status != DemuxerStream::kOk, !input.get()) << status;
 
+  // Drop the buffer, fire |read_cb_| and complete the pending Stop().
+  if (!stop_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(kAborted, NULL);
+    DoStop();
+    return;
+  }
+
+  // Drop the buffer, fire |read_cb_| and complete the pending Reset().
+  if (!reset_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(kAborted, NULL);
+    DoReset();
+    return;
+  }
+
   if (status == DemuxerStream::kAborted) {
     DCHECK(!input.get());
     base::ResetAndReturn(&read_cb_).Run(kAborted, NULL);
     return;
   }
 
   if (status == DemuxerStream::kConfigChanged) {
     DCHECK(!input.get());
     DVLOG(1) << "Config changed.";
 
@@ skipping 261 matching lines @@
   output_timestamp_helper_->AddFrames(frames_decoded);
 
   // Discard the buffer to indicate we need more data.
   if (!frames_to_output)
     *output_buffer = NULL;
 
   return true;
 }
 
 }  // namespace media