Update AudioRenderer API to fire changes in BufferingState.

media/base/pipeline.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/base/pipeline.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 396 matching lines @@
           metadata.natural_size = stream->video_decoder_config().natural_size();
         metadata_cb_.Run(metadata);
       }
 
       return DoInitialPreroll(done_cb);
 
     case kPlaying:
       PlaybackRateChangedTask(GetPlaybackRate());
       VolumeChangedTask(GetVolume());
 
+      // Handle renderers that immediately signal they have enough data.
+      if (!WaitingForEnoughData())
+        StartPlayback();
+
       // We enter this state from either kInitPrerolling or kSeeking. As of now
       // both those states call Preroll(), which means by time we enter this
       // state we've already buffered enough data. Forcefully update the
       // buffering state, which start the clock and renderers and transition
       // into kPlaying state.
       //
       // TODO(scherkus): Remove after renderers are taught to fire buffering
       // state callbacks http://crbug.com/144683
-      DCHECK(WaitingForEnoughData());
-      if (audio_renderer_)
-        BufferingStateChanged(&audio_buffering_state_, BUFFERING_HAVE_ENOUGH);
-      if (video_renderer_)
+      if (video_renderer_) {
+        DCHECK(WaitingForEnoughData());
         BufferingStateChanged(&video_buffering_state_, BUFFERING_HAVE_ENOUGH);
+      }
       return;
 
     case kStopping:
     case kStopped:
     case kCreated:
     case kSeeking:
       NOTREACHED() << "State has no transition: " << state_;
       return;
   }
 }
 
 // Note that the usage of base::Unretained() with the audio/video renderers
 // in the following DoXXX() functions is considered safe as they are owned by
 // |pending_callbacks_| and share the same lifetime.
 //
 // That being said, deleting the renderers while keeping |pending_callbacks_|
 // running on the media thread would result in crashes.
 void Pipeline::DoInitialPreroll(const PipelineStatusCB& done_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!pending_callbacks_.get());
   SerialRunner::Queue bound_fns;
 
   base::TimeDelta seek_timestamp = demuxer_->GetStartTime();
 
   // Preroll renderers.
   if (audio_renderer_) {
-    bound_fns.Push(base::Bind(
-        &AudioRenderer::Preroll, base::Unretained(audio_renderer_.get()),
-        seek_timestamp));
+    bound_fns.Push(base::Bind(&AudioRenderer::StartPlayingFrom,
+                              base::Unretained(audio_renderer_.get()),
+                              seek_timestamp));
   }
 
   if (video_renderer_) {
     bound_fns.Push(base::Bind(
         &VideoRenderer::Preroll, base::Unretained(video_renderer_.get()),
         seek_timestamp));
 
     // TODO(scherkus): Remove after VideoRenderer is taught to fire buffering
     // state callbacks http://crbug.com/144683
     bound_fns.Push(base::Bind(&VideoRenderer::Play,
                               base::Unretained(video_renderer_.get())));
   }
 
   if (text_renderer_) {
     bound_fns.Push(base::Bind(
         &TextRenderer::Play, base::Unretained(text_renderer_.get())));
   }
 
   pending_callbacks_ = SerialRunner::Run(bound_fns, done_cb);
 }
 
+#if DCHECK_IS_ON
+static void VerifyBufferingStates(BufferingState* audio_buffering_state,
+                                  BufferingState* video_buffering_state) {
+  DCHECK_EQ(*audio_buffering_state, BUFFERING_HAVE_NOTHING);
+  DCHECK_EQ(*video_buffering_state, BUFFERING_HAVE_NOTHING);
+}
+#endif
+
 void Pipeline::DoSeek(
     base::TimeDelta seek_timestamp,
     const PipelineStatusCB& done_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!pending_callbacks_.get());
   SerialRunner::Queue bound_fns;
 
   // Pause.
   if (text_renderer_) {
     bound_fns.Push(base::Bind(
         &TextRenderer::Pause, base::Unretained(text_renderer_.get())));
   }
 
   // Flush.
   if (audio_renderer_) {
     bound_fns.Push(base::Bind(
         &AudioRenderer::Flush, base::Unretained(audio_renderer_.get())));
+  }
 
-    // TODO(scherkus): Remove after AudioRenderer is taught to fire buffering
-    // state callbacks http://crbug.com/144683
-    bound_fns.Push(base::Bind(&Pipeline::BufferingStateChanged,
-                              base::Unretained(this),
-                              &audio_buffering_state_,
-                              BUFFERING_HAVE_NOTHING));
-  }
   if (video_renderer_) {
     bound_fns.Push(base::Bind(
         &VideoRenderer::Flush, base::Unretained(video_renderer_.get())));
 
     // TODO(scherkus): Remove after VideoRenderer is taught to fire buffering
     // state callbacks http://crbug.com/144683
     bound_fns.Push(base::Bind(&Pipeline::BufferingStateChanged,
                               base::Unretained(this),
                               &video_buffering_state_,
                               BUFFERING_HAVE_NOTHING));
   }
+
+#if DCHECK_IS_ON
+  // Verify renderers reset their buffering states.
+  bound_fns.Push(base::Bind(&VerifyBufferingStates,
+                            &audio_buffering_state_,
+                            &video_buffering_state_));
+#endif
+
   if (text_renderer_) {
     bound_fns.Push(base::Bind(
         &TextRenderer::Flush, base::Unretained(text_renderer_.get())));
   }
 
   // Seek demuxer.
   bound_fns.Push(base::Bind(
       &Demuxer::Seek, base::Unretained(demuxer_), seek_timestamp));
 
   // Preroll renderers.
   if (audio_renderer_) {
-    bound_fns.Push(base::Bind(
-        &AudioRenderer::Preroll, base::Unretained(audio_renderer_.get()),
-        seek_timestamp));
+    bound_fns.Push(base::Bind(&AudioRenderer::StartPlayingFrom,
+                              base::Unretained(audio_renderer_.get()),
+                              seek_timestamp));
   }
 
   if (video_renderer_) {
     bound_fns.Push(base::Bind(
         &VideoRenderer::Preroll, base::Unretained(video_renderer_.get()),
         seek_timestamp));
 
     // TODO(scherkus): Remove after renderers are taught to fire buffering
     // state callbacks http://crbug.com/144683
     bound_fns.Push(base::Bind(&VideoRenderer::Play,
@@ skipping 309 matching lines @@
 }
 
 void Pipeline::InitializeAudioRenderer(const PipelineStatusCB& done_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   audio_renderer_ = filter_collection_->GetAudioRenderer();
   audio_renderer_->Initialize(
       demuxer_->GetStream(DemuxerStream::AUDIO),
       done_cb,
       base::Bind(&Pipeline::OnUpdateStatistics, base::Unretained(this)),
-      base::Bind(&Pipeline::OnAudioUnderflow, base::Unretained(this)),
       base::Bind(&Pipeline::OnAudioTimeUpdate, base::Unretained(this)),
+      base::Bind(&Pipeline::BufferingStateChanged, base::Unretained(this),
+                 &audio_buffering_state_),
       base::Bind(&Pipeline::OnAudioRendererEnded, base::Unretained(this)),
       base::Bind(&Pipeline::SetError, base::Unretained(this)));
 }
 
 void Pipeline::InitializeVideoRenderer(const PipelineStatusCB& done_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   video_renderer_ = filter_collection_->GetVideoRenderer();
   video_renderer_->Initialize(
       demuxer_->GetStream(DemuxerStream::VIDEO),
       demuxer_->GetLiveness() == Demuxer::LIVENESS_LIVE,
       done_cb,
       base::Bind(&Pipeline::OnUpdateStatistics, base::Unretained(this)),
       base::Bind(&Pipeline::OnVideoTimeUpdate, base::Unretained(this)),
       base::Bind(&Pipeline::OnVideoRendererEnded, base::Unretained(this)),
       base::Bind(&Pipeline::SetError, base::Unretained(this)),
       base::Bind(&Pipeline::GetMediaTime, base::Unretained(this)),
       base::Bind(&Pipeline::GetMediaDuration, base::Unretained(this)));
 }
 
-void Pipeline::OnAudioUnderflow() {
-  if (!task_runner_->BelongsToCurrentThread()) {
-    task_runner_->PostTask(FROM_HERE, base::Bind(
-        &Pipeline::OnAudioUnderflow, base::Unretained(this)));
-    return;
-  }
-
-  if (state_ != kPlaying)
-    return;
-
-  if (audio_renderer_)
-    audio_renderer_->ResumeAfterUnderflow();
-}
-
 void Pipeline::BufferingStateChanged(BufferingState* buffering_state,
                                      BufferingState new_buffering_state) {
   DVLOG(1) << __FUNCTION__ << "(" << *buffering_state << ", "
            << " " << new_buffering_state << ") "
            << (buffering_state == &audio_buffering_state_ ? "audio" : "video");
   DCHECK(task_runner_->BelongsToCurrentThread());
   bool was_waiting_for_enough_data = WaitingForEnoughData();
   *buffering_state = new_buffering_state;
 
   // Renderer underflowed.
   if (!was_waiting_for_enough_data && WaitingForEnoughData()) {
-    StartWaitingForEnoughData();
+    PausePlayback();
     return;
   }
 
   // Renderer prerolled.
   if (was_waiting_for_enough_data && !WaitingForEnoughData()) {
     StartPlayback();
     return;
   }
 }
 
 bool Pipeline::WaitingForEnoughData() const {
   DCHECK(task_runner_->BelongsToCurrentThread());
   if (state_ != kPlaying)
     return false;
   if (audio_renderer_ && audio_buffering_state_ != BUFFERING_HAVE_ENOUGH)
     return true;
   if (video_renderer_ && video_buffering_state_ != BUFFERING_HAVE_ENOUGH)
     return true;
   return false;
 }
 
-void Pipeline::StartWaitingForEnoughData() {
+void Pipeline::PausePlayback() {
   DVLOG(1) << __FUNCTION__;
   DCHECK_EQ(state_, kPlaying);
   DCHECK(WaitingForEnoughData());
+  DCHECK(task_runner_->BelongsToCurrentThread());
 
   base::AutoLock auto_lock(lock_);
   PauseClockAndStopRendering_Locked();
 }
 
 void Pipeline::StartPlayback() {
   DVLOG(1) << __FUNCTION__;
   DCHECK_EQ(state_, kPlaying);
   DCHECK_EQ(clock_state_, CLOCK_PAUSED);
   DCHECK(!WaitingForEnoughData());
+  DCHECK(task_runner_->BelongsToCurrentThread());
 
   if (audio_renderer_) {
     // We use audio stream to update the clock. So if there is such a
     // stream, we pause the clock until we receive a valid timestamp.
     base::AutoLock auto_lock(lock_);
     clock_state_ = CLOCK_WAITING_FOR_AUDIO_TIME_UPDATE;
     audio_renderer_->StartRendering();
   } else {
     base::AutoLock auto_lock(lock_);
     clock_state_ = CLOCK_PLAYING;
@@ skipping 29 matching lines @@
 void Pipeline::StartClockIfWaitingForTimeUpdate_Locked() {
   lock_.AssertAcquired();
   if (clock_state_ != CLOCK_WAITING_FOR_AUDIO_TIME_UPDATE)
     return;
 
   clock_state_ = CLOCK_PLAYING;
   clock_->Play();
 }
 
 }  // namespace media