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 DataSource {
  15  public:
  16   typedef base::Callback<void(int64, int64)> StatusCallback;
  17   typedef base::Callback<void(int)> ReadCB;
  18
  19   enum { kReadError = -1 };
  20
  21   DataSource();
  22   virtual ~DataSource();
  23
  24   // Reads |size| bytes from |position| into |data|. And when the read is done
  25   // or failed, |read_cb| is called with the number of bytes read or
  26   // kReadError in case of error.
  27   virtual void Read(int64 position, int size, uint8* data,
  28                     const DataSource::ReadCB& read_cb) = 0;
  29
  30   // Stops the DataSource. Once this is called all future Read() calls will
  31   // return an error.
  32   virtual void Stop() = 0;
  33
  34   // Returns true and the file size, false if the file size could not be
  35   // retrieved.
  36   virtual bool GetSize(int64* size_out) = 0;
  37
  38   // Returns true if we are performing streaming. In this case seeking is
  39   // not possible.
  40   virtual bool IsStreaming() = 0;
  41
  42   // Notify the DataSource of the bitrate of the media.
  43   // Values of |bitrate| <= 0 are invalid and should be ignored.
  44   virtual void SetBitrate(int bitrate) = 0;
  45
  46  private:
  47   DISALLOW_COPY_AND_ASSIGN(DataSource);
  48 };
  49
  50 }  // namespace media
  51
  52 #endif  // MEDIA_BASE_DATA_SOURCE_H_