media/filters/decrypting_demuxer_stream.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_FILTERS_DECRYPTING_DEMUXER_STREAM_H_
   6 #define MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "media/base/audio_decoder_config.h"
  12 #include "media/base/decryptor.h"
  13 #include "media/base/demuxer_stream.h"
  14 #include "media/base/pipeline_status.h"
  15 #include "media/base/video_decoder_config.h"
  16
  17 namespace base {
  18 class MessageLoopProxy;
  19 }
  20
  21 namespace media {
  22
  23 class DecoderBuffer;
  24
  25 // Decryptor-based DemuxerStream implementation that converts a potentially
  26 // encrypted demuxer stream to a clear demuxer stream.
  27 // All public APIs and callbacks are trampolined to the |message_loop_| so
  28 // that no locks are required for thread safety.
  29 class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
  30  public:
  31   DecryptingDemuxerStream(
  32       const scoped_refptr<base::MessageLoopProxy>& message_loop,
  33       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  34   virtual ~DecryptingDemuxerStream();
  35
  36   void Initialize(DemuxerStream* stream,
  37                   const PipelineStatusCB& status_cb);
  38   void Reset(const base::Closure& closure);
  39
  40   // DemuxerStream implementation.
  41   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  42   virtual AudioDecoderConfig audio_decoder_config() OVERRIDE;
  43   virtual VideoDecoderConfig video_decoder_config() OVERRIDE;
  44   virtual Type type() OVERRIDE;
  45   virtual void EnableBitstreamConverter() OVERRIDE;
  46
  47  private:
  48   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  49   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  50   // stabilizes.
  51   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  52   enum State {
  53     kUninitialized = 0,
  54     kDecryptorRequested,
  55     kIdle,
  56     kPendingDemuxerRead,
  57     kPendingDecrypt,
  58     kWaitingForKey,
  59   };
  60
  61   // Callback for DecryptorHost::RequestDecryptor().
  62   void SetDecryptor(Decryptor* decryptor);
  63
  64   // Callback for DemuxerStream::Read().
  65   void DecryptBuffer(DemuxerStream::Status status,
  66                      const scoped_refptr<DecoderBuffer>& buffer);
  67
  68   void DecryptPendingBuffer();
  69
  70   // Callback for Decryptor::Decrypt().
  71   void DeliverBuffer(Decryptor::Status status,
  72                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  73
  74   // Callback for the |decryptor_| to notify this object that a new key has been
  75   // added.
  76   void OnKeyAdded();
  77
  78   // Resets decoder and calls |reset_cb_|.
  79   void DoReset();
  80
  81   // Returns Decryptor::StreamType converted from |stream_type_|.
  82   Decryptor::StreamType GetDecryptorStreamType() const;
  83
  84   // Creates and initializes either |audio_config_| or |video_config_| based on
  85   // |demuxer_stream_|.
  86   void InitializeDecoderConfig();
  87
  88   scoped_refptr<base::MessageLoopProxy> message_loop_;
  89   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
  90   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
  91
  92   State state_;
  93
  94   PipelineStatusCB init_cb_;
  95   ReadCB read_cb_;
  96   base::Closure reset_cb_;
  97
  98   // Pointer to the input demuxer stream that will feed us encrypted buffers.
  99   DemuxerStream* demuxer_stream_;
 100
 101   AudioDecoderConfig audio_config_;
 102   VideoDecoderConfig video_config_;
 103
 104   // Callback to request/cancel decryptor creation notification.
 105   SetDecryptorReadyCB set_decryptor_ready_cb_;
 106
 107   Decryptor* decryptor_;
 108
 109   // The buffer returned by the demuxer that needs to be decrypted.
 110   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 111
 112   // Indicates the situation where new key is added during pending decryption
 113   // (in other words, this variable can only be set in state kPendingDecrypt).
 114   // If this variable is true and kNoKey is returned then we need to try
 115   // decrypting again in case the newly added key is the correct decryption key.
 116   bool key_added_while_decrypt_pending_;
 117
 118   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 119 };
 120
 121 }  // namespace media
 122
 123 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_