Cancel pending seek in ChunkDemuxer when a new seek occurs

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 581b245dbc2bb77782ce893c5a05ad7f26dcdbe4..6e5ded89bf7e1b36ff47049651792d2e7189399f 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -173,6 +173,7 @@ class ChunkDemuxerStream : public DemuxerStream {
 
   void StartWaitingForSeek();
   void Seek(TimeDelta time);
+  void BeginReturningNullBuffers();
   bool IsSeekPending() const;
 
   // Add buffers to this stream.  Buffers are stored in SourceBufferStreams,
@@ -214,6 +215,7 @@ class ChunkDemuxerStream : public DemuxerStream {
   enum State {
     RETURNING_DATA_FOR_READS,
     WAITING_FOR_SEEK,
+    CANCELED,
     SHUTDOWN,
   };
 
@@ -280,12 +282,21 @@ void ChunkDemuxerStream::Seek(TimeDelta time) {
 
   DCHECK(read_cbs_.empty());
 
+  // Ignore seek requests when cancelled.
+  if (state_ == CANCELED)
+    return;
+
   stream_->Seek(time);
 
   if (state_ == WAITING_FOR_SEEK)
     ChangeState_Locked(RETURNING_DATA_FOR_READS);
 }
 
+void ChunkDemuxerStream::BeginReturningNullBuffers() {
+  base::AutoLock auto_lock(lock_);
+  ChangeState_Locked(CANCELED);

[acolwell GONE FROM CHROMIUM, 2012/08/07 20:26:51]

I think you may need to copy the read_cbs code from StartWaitingForSeek() to
here as well since any pending reads will need to be aborted.

[vrk (LEFT CHROMIUM), 2012/08/07 22:44:51]

Done.

+}
+
 bool ChunkDemuxerStream::IsSeekPending() const {
   base::AutoLock auto_lock(lock_);
   return stream_->IsSeekPending();
@@ -490,6 +501,7 @@ bool ChunkDemuxerStream::GetNextBuffer_Locked(
           return true;
       }
       break;
+    case CANCELED:
     case WAITING_FOR_SEEK:
       // Null buffers should be returned in this state since we are waiting
       // for a seek. Any buffers in the SourceBuffer should NOT be returned
@@ -605,6 +617,25 @@ void ChunkDemuxer::StartWaitingForSeek() {
   ChangeState_Locked(INITIALIZED);
 }
 
+void ChunkDemuxer::CancelPendingSeek() {
+  PipelineStatusCB cb;
+  {
+    base::AutoLock auto_lock(lock_);
+    if (IsSeekPending_Locked() && !seek_cb_.is_null()) {
+      std::swap(cb, seek_cb_);
+    }
+  }
+
+  if (audio_)
+    audio_->BeginReturningNullBuffers();

[acolwell GONE FROM CHROMIUM, 2012/08/07 20:26:51]

nit:s/BeginReturningNullBuffers/CancelPendingSeek/ ?

[vrk (LEFT CHROMIUM), 2012/08/07 22:44:51]

...yeah that would make more sense :P Done!

+
+  if (video_)
+    video_->BeginReturningNullBuffers();
+
+  if (!cb.is_null())
+    cb.Run(PIPELINE_OK);
+}
+
 ChunkDemuxer::Status ChunkDemuxer::AddId(const std::string& id,
                                          const std::string& type,
                                          std::vector<std::string>& codecs) {