Fix ChunkDemuxer seek deadlock

media/filters/audio_renderer_base.h

 // 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.
 
 // AudioRendererBase takes care of the tricky queuing work and provides simple
 // methods for subclasses to peek and poke at audio data.  In addition to
 // AudioRenderer interface methods this classes doesn't implement, subclasses
 // must also implement the following methods:
 //   OnInitialized
 //   OnStop
@@ skipping 44 matching lines @@
   // otherwise.
   virtual bool OnInitialize(int bits_per_channel,
                             ChannelLayout channel_layout,
                             int sample_rate) = 0;
 
   // Called by Stop().  Subclasses should perform any necessary cleanup during
   // this time, such as stopping any running threads.
   virtual void OnStop() = 0;
 
   // Method called by FillBuffer() when it finds that it reached end of stream.
   // FillBuffer() cannot immediately signal end of stream event because browser

[Ami GONE FROM CHROMIUM, 2012/01/30 17:37:42]

The second sentence of this para should be an explanation of what subclasses
might/should do in this case (I believe that is: drain output buffers and call
SignalEOS() back on this class).

[acolwell GONE FROM CHROMIUM, 2012/01/30 22:01:17]

This is from a rebase. I'll fix it in a separate CL.

   // may have buffered data.
   virtual void OnRenderEndOfStream() = 0;
 
   // Callback from the audio decoder delivering decoded audio samples.
   void DecodedAudioReady(scoped_refptr<Buffer> buffer);
 
   // Fills the given buffer with audio data by delegating to its |algorithm_|.
   // FillBuffer() also takes care of updating the clock. Returns the number of
   // bytes copied into |dest|, which may be less than or equal to |len|.
   //
@@ skipping 15 matching lines @@
   // buffers become empty (i.e. when all the data written to the device has
   // been played).
   //
   // Safe to call on any thread.
   uint32 FillBuffer(uint8* dest,
                     uint32 len,
                     const base::TimeDelta& playback_delay);
 
   // Called by OnRenderEndOfStream() or some callback scheduled by derived class
   // to signal end of stream.
   void SignalEndOfStream();

[Ami GONE FROM CHROMIUM, 2012/01/30 17:37:42]

I am unhappy about the names OnRenderEOS / SignalEOS.

IIUC, rendered_end_of_stream_ is really not about EOS at all, but rather about
the Pipeline concept of "ended".

WDYT of:
s/SignalEndOfStream/NotifyEndedDone/  ("Done" to include buffers flushing; open
to better names)
s/OnRenderEndOfStream/OnEndOfStream/
s/rendered_end_of_stream_/ended_/
?

[acolwell GONE FROM CHROMIUM, 2012/01/30 22:01:17]

This is from a rebase. I'll fix it in a separate CL.

 
   // Get/Set the playback rate of |algorithm_|.
   virtual void SetPlaybackRate(float playback_rate) OVERRIDE;
   virtual float GetPlaybackRate();
 
  private:
   friend class AudioRendererBaseTest;
 
   // Helper method that schedules an asynchronous read from the decoder and
   // increments |pending_reads_|.
   //
   // Safe to call from any thread.
   void ScheduleRead_Locked();
 
+  // Returns true if the data in the buffer is all before
+  // |seek_timestamp_|. This can only return true while
+  // in the kSeeking state.
+  bool IsBeforeSeekTime(const scoped_refptr<Buffer>& buffer);
+
   // Audio decoder.
   scoped_refptr<AudioDecoder> decoder_;
 
   // Algorithm for scaling audio.
   scoped_ptr<AudioRendererAlgorithmBase> algorithm_;
 
   base::Lock lock_;
 
   // Simple state tracking variable.
   enum State {
     kUninitialized,
     kPaused,
     kSeeking,
     kPlaying,
     kStopped,
-    kError,
     kUnderflow,
     kRebuffering,
   };
   State state_;
 
   // Keep track of our outstanding read to |decoder_|.
   bool pending_read_;
 
   // Keeps track of whether we received and rendered the end of stream buffer.
   bool recieved_end_of_stream_;
@@ skipping 12 matching lines @@
   base::TimeDelta seek_timestamp_;
 
   AudioDecoder::ReadCB read_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_AUDIO_RENDERER_BASE_H_