Ensure media's buffered ranges always have a range that includes currentTime.

media/filters/ffmpeg_demuxer.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.
 
 // Implements the Demuxer interface using FFmpeg's libavformat.  At this time
 // will support demuxing any audio/video format thrown at it.  The streams
 // output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
 // key FFmpegCodecID which contains the CodecID enumeration value.  The CodecIDs
 // can be used to create and initialize the corresponding FFmpeg decoder.
 //
@@ skipping 29 matching lines @@
 struct AVPacket;
 struct AVRational;
 struct AVStream;
 
 namespace media {
 
 class BitstreamConverter;
 class FFmpegDemuxer;
 class ScopedPtrAVFreePacket;
 
+typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> NotifyBufferedCB;
+
 class FFmpegDemuxerStream : public DemuxerStream {
  public:
   // Keeps a copy of |demuxer| and initializes itself using information
   // inside |stream|.  Both parameters must outlive |this|.
-  FFmpegDemuxerStream(FFmpegDemuxer* demuxer, AVStream* stream);
+  FFmpegDemuxerStream(const NotifyBufferedCB& notify_buffered_cb_,
+                      FFmpegDemuxer* demuxer, AVStream* stream);
 
   // Returns true is this stream has pending reads, false otherwise.
   //
   // Safe to call on any thread.
   bool HasPendingReads();
 
   // Enqueues the given AVPacket.  If |packet| is NULL an end of stream packet
   // is enqueued.
   void EnqueuePacket(scoped_ptr_malloc<AVPacket, ScopedPtrAVFreePacket> packet);
 
@@ skipping 35 matching lines @@
 
   // Attempts to fulfill a single pending read by dequeueing a buffer and read
   // callback pair and executing the callback. The calling function must
   // acquire |lock_| before calling this function.
   void FulfillPendingRead();
 
   // Converts an FFmpeg stream timestamp into a base::TimeDelta.
   static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
                                                 int64 timestamp);
 
+  NotifyBufferedCB notify_buffered_cb_;
   FFmpegDemuxer* demuxer_;
   AVStream* stream_;
   AudioDecoderConfig audio_config_;
   VideoDecoderConfig video_config_;
   Type type_;
   base::TimeDelta duration_;
   bool discontinuous_;
   bool stopped_;
+  base::TimeDelta last_packet_timestamp_;
 
   typedef std::deque<scoped_refptr<DecoderBuffer> > BufferQueue;
   BufferQueue buffer_queue_;
 
   typedef std::deque<ReadCB> ReadQueue;
   ReadQueue read_queue_;
 
   // Used to translate bitstream formats.
   scoped_ptr<BitstreamConverter> bitstream_converter_;
 
@@ skipping 70 matching lines @@
   // Must be called on the demuxer thread.
   void StreamHasEnded();
 
   // Wait for asynchronous read to complete and return number of bytes read.
   virtual int WaitForRead();
 
   // Signal the blocked thread that the read has completed, with |size| bytes
   // read or kReadError in case of error.
   virtual void SignalReadCompleted(int size);
 
+  // Callback for DemuxerStreams to notify us they've buffered a time range,
+  // which we then percolate upwards.
+  void NotifyBufferedRange(
+      int stream_id, base::TimeDelta start, base::TimeDelta end);
+
   DemuxerHost* host_;
 
   MessageLoop* message_loop_;
 
   // FFmpeg context handle.
   AVFormatContext* format_context_;
 
   // |streams_| mirrors the AVStream array in |format_context_|. It contains
   // FFmpegDemuxerStreams encapsluating AVStream objects at the same index.
   //
   // Since we only support a single audio and video stream, |streams_| will
   // contain NULL entries for additional audio/video streams as well as for
   // stream types that we do not currently support.
   //
   // Once initialized, operations on FFmpegDemuxerStreams should be carried out
   // on the demuxer thread.
   typedef std::vector<scoped_refptr<FFmpegDemuxerStream> > StreamVector;
   StreamVector streams_;
 
+  // The times buffered by each stream.
+  std::vector<Ranges<base::TimeDelta> > buffered_times_;
+
   // Reference to the data source. Asynchronous read requests are submitted to
   // this object.
   scoped_refptr<DataSource> data_source_;
 
   // This member is used to block on read method calls from FFmpeg and wait
   // until the asynchronous reads in the data source to complete. It is also
   // signaled when the demuxer is being stopped.
   base::WaitableEvent read_event_;
 
   // Flag to indicate if read has ever failed. Once set to true, it will
@@ skipping 18 matching lines @@
   // Set if we know duration of the audio stream. Used when processing end of
   // stream -- at this moment we definitely know duration.
   bool duration_known_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_