media/base/data_source.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_BASE_DATA_SOURCE_H_
   6 #define MEDIA_BASE_DATA_SOURCE_H_
   7
   8 #include "base/callback.h"
   9 #include "base/time/time.h"
  10 #include "media/base/media_export.h"
  11
  12 namespace media {
  13
  14 class MEDIA_EXPORT DataSourceHost {
  15  public:
  16   // Set the total size of the media file.
  17   virtual void SetTotalBytes(int64 total_bytes) = 0;
  18
  19   // Notify the host that byte range [start,end] has been buffered.
  20   // TODO(fischman): remove this method when demuxing is push-based instead of
  21   // pull-based.  http://crbug.com/131444
  22   virtual void AddBufferedByteRange(int64 start, int64 end) = 0;
  23
  24   // Notify the host that time range [start,end] has been buffered.
  25   virtual void AddBufferedTimeRange(base::TimeDelta start,
  26                                     base::TimeDelta end) = 0;
  27
  28  protected:
  29   virtual ~DataSourceHost();
  30 };
  31
  32 class MEDIA_EXPORT DataSource {
  33  public:
  34   typedef base::Callback<void(int64, int64)> StatusCallback;
  35   typedef base::Callback<void(int)> ReadCB;
  36   static const int kReadError;
  37
  38   DataSource();
  39   virtual ~DataSource();
  40
  41   virtual void set_host(DataSourceHost* host);
  42
  43   // Reads |size| bytes from |position| into |data|. And when the read is done
  44   // or failed, |read_cb| is called with the number of bytes read or
  45   // kReadError in case of error.
  46   virtual void Read(int64 position, int size, uint8* data,
  47                     const DataSource::ReadCB& read_cb) = 0;
  48
  49   // Notifies the DataSource of a change in the current playback rate.
  50   virtual void SetPlaybackRate(float playback_rate);
  51
  52   // Stops the DataSource. Once this is called all future Read() calls will
  53   // return an error.
  54   virtual void Stop(const base::Closure& callback) = 0;
  55
  56   // Returns true and the file size, false if the file size could not be
  57   // retrieved.
  58   virtual bool GetSize(int64* size_out) = 0;
  59
  60   // Returns true if we are performing streaming. In this case seeking is
  61   // not possible.
  62   virtual bool IsStreaming() = 0;
  63
  64   // Notify the DataSource of the bitrate of the media.
  65   // Values of |bitrate| <= 0 are invalid and should be ignored.
  66   virtual void SetBitrate(int bitrate) = 0;
  67
  68  protected:
  69   DataSourceHost* host();
  70
  71  private:
  72   DataSourceHost* host_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(DataSource);
  75 };
  76
  77 }  // namespace media
  78
  79 #endif  // MEDIA_BASE_DATA_SOURCE_H_