Add support for cancellation of demuxer reads.

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 <memory>
 #include <utility>
 
@@ skipping 574 matching lines @@
   // Reset bitstream for converter to do so.
   // This is related to chromium issue 140371 (http://crbug.com/140371).
   ResetBitstreamConverter();
 
   buffer_queue_.Clear();
   end_of_stream_ = false;
   last_packet_timestamp_ = kNoTimestamp;
   last_packet_duration_ = kNoTimestamp;
 }
 
+void FFmpegDemuxerStream::Abort() {
+  if (!read_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(DemuxerStream::kOk,
+                                        DecoderBuffer::CreateEOSBuffer());
+  }
+}
+
 void FFmpegDemuxerStream::Stop() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   buffer_queue_.Clear();
   if (!read_cb_.is_null()) {
     base::ResetAndReturn(&read_cb_).Run(
         DemuxerStream::kOk, DecoderBuffer::CreateEOSBuffer());
   }
   demuxer_ = NULL;
   stream_ = NULL;
   end_of_stream_ = true;
@@ skipping 269 matching lines @@
 
   // Open the AVFormatContext using our glue layer.
   CHECK(blocking_thread_.Start());
   base::PostTaskAndReplyWithResult(
       blocking_thread_.task_runner().get(), FROM_HERE,
       base::Bind(&FFmpegGlue::OpenContext, base::Unretained(glue_.get())),
       base::Bind(&FFmpegDemuxer::OnOpenContextDone, weak_factory_.GetWeakPtr(),
                  status_cb));
 }
 
+void FFmpegDemuxer::AbortPendingReads() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+
+  // This should only be called after the demuxer has been initialized.
+  DCHECK(blocking_thread_.IsRunning());
+  DCHECK_GT(streams_.size(), 0u);
+
+  // Abort all outstanding reads by returning EOS buffers (to avoid any errors
+  // being triggered in the pipeline).
+  for (auto* stream : streams_) {
+    if (stream)
+      stream->Abort();
+  }
+
+  // Ordering is important here, we want to ignore any errors that occur during
+  // the Abort() of the data source. Note: We don't abort the URLProtocol here
+  // since that is a permanent action.
+  weak_factory_.InvalidateWeakPtrs();
+  data_source_->Abort();
+}
+
 void FFmpegDemuxer::Stop() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   // The order of Stop() and Abort() is important here.  If Abort() is called
   // first, control may pass into FFmpeg where it can destruct buffers that are
   // in the process of being fulfilled by the DataSource.
   data_source_->Stop();
   url_protocol_->Abort();
 
   // This will block until all tasks complete. Note that after this returns it's
@@ skipping 803 matching lines @@
 
 void FFmpegDemuxer::SetLiveness(DemuxerStream::Liveness liveness) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   for (auto* stream : streams_) {
     if (stream)
       stream->SetLiveness(liveness);
   }
 }
 
 }  // namespace media