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 SingleThreadTaskRunner;
  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 |task_runner_| 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::SingleThreadTaskRunner>& task_runner,
  33       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  34   virtual ~DecryptingDemuxerStream();
  35
  36   void Initialize(DemuxerStream* stream,
  37                   const PipelineStatusCB& status_cb);
  38
  39   // Cancels all pending operations and fires all pending callbacks.  Sets
  40   // |this| to kUninitialized state if |this| hasn't been initialized, or to
  41   // kIdle state otherwise.
  42   void Reset(const base::Closure& closure);
  43
  44   // DemuxerStream implementation.
  45   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  46   virtual AudioDecoderConfig audio_decoder_config() OVERRIDE;
  47   virtual VideoDecoderConfig video_decoder_config() OVERRIDE;
  48   virtual Type type() OVERRIDE;
  49   virtual void EnableBitstreamConverter() OVERRIDE;
  50
  51  private:
  52   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  53   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  54   // stabilizes.
  55   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  56   enum State {
  57     kUninitialized = 0,
  58     kDecryptorRequested,
  59     kIdle,
  60     kPendingDemuxerRead,
  61     kPendingDecrypt,
  62     kWaitingForKey,
  63   };
  64
  65   // Callback for DecryptorHost::RequestDecryptor().
  66   void SetDecryptor(Decryptor* decryptor);
  67
  68   // Callback for DemuxerStream::Read().
  69   void DecryptBuffer(DemuxerStream::Status status,
  70                      const scoped_refptr<DecoderBuffer>& buffer);
  71
  72   void DecryptPendingBuffer();
  73
  74   // Callback for Decryptor::Decrypt().
  75   void DeliverBuffer(Decryptor::Status status,
  76                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  77
  78   // Callback for the |decryptor_| to notify this object that a new key has been
  79   // added.
  80   void OnKeyAdded();
  81
  82   // Resets decoder and calls |reset_cb_|.
  83   void DoReset();
  84
  85   // Returns Decryptor::StreamType converted from |stream_type_|.
  86   Decryptor::StreamType GetDecryptorStreamType() const;
  87
  88   // Creates and initializes either |audio_config_| or |video_config_| based on
  89   // |demuxer_stream_|.
  90   void InitializeDecoderConfig();
  91
  92   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  93   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
  94   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
  95
  96   State state_;
  97
  98   PipelineStatusCB init_cb_;
  99   ReadCB read_cb_;
 100   base::Closure reset_cb_;
 101
 102   // Pointer to the input demuxer stream that will feed us encrypted buffers.
 103   DemuxerStream* demuxer_stream_;
 104
 105   AudioDecoderConfig audio_config_;
 106   VideoDecoderConfig video_config_;
 107
 108   // Callback to request/cancel decryptor creation notification.
 109   SetDecryptorReadyCB set_decryptor_ready_cb_;
 110
 111   Decryptor* decryptor_;
 112
 113   // The buffer returned by the demuxer that needs to be decrypted.
 114   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 115
 116   // Indicates the situation where new key is added during pending decryption
 117   // (in other words, this variable can only be set in state kPendingDecrypt).
 118   // If this variable is true and kNoKey is returned then we need to try
 119   // decrypting again in case the newly added key is the correct decryption key.
 120   bool key_added_while_decrypt_pending_;
 121
 122   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 123 };
 124
 125 }  // namespace media
 126
 127 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_