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       const base::Closure& waiting_for_decryption_key_cb);
  35
  36   // Cancels all pending operations immediately and fires all pending callbacks.
  37   ~DecryptingDemuxerStream() override;
  38
  39   void Initialize(DemuxerStream* stream,
  40                   const PipelineStatusCB& status_cb);
  41
  42   // Cancels all pending operations and fires all pending callbacks. If in
  43   // kPendingDemuxerRead or kPendingDecrypt state, waits for the pending
  44   // operation to finish before satisfying |closure|. Sets the state to
  45   // kUninitialized if |this| hasn't been initialized, or to kIdle otherwise.
  46   void Reset(const base::Closure& closure);
  47
  48   // DemuxerStream implementation.
  49   void Read(const ReadCB& read_cb) override;
  50   AudioDecoderConfig audio_decoder_config() override;
  51   VideoDecoderConfig video_decoder_config() override;
  52   Type type() const override;
  53   Liveness liveness() const override;
  54   void EnableBitstreamConverter() override;
  55   bool SupportsConfigChanges() override;
  56   VideoRotation video_rotation() override;
  57
  58  private:
  59   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  60   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  61   // stabilizes.
  62   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  63   enum State {
  64     kUninitialized = 0,
  65     kDecryptorRequested,
  66     kIdle,
  67     kPendingDemuxerRead,
  68     kPendingDecrypt,
  69     kWaitingForKey
  70   };
  71
  72   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  73   // called when the decryptor has been completely attached to the pipeline.
  74   void SetDecryptor(Decryptor* decryptor,
  75                     const DecryptorAttachedCB& decryptor_attached_cb);
  76
  77   // Callback for DemuxerStream::Read().
  78   void DecryptBuffer(DemuxerStream::Status status,
  79                      const scoped_refptr<DecoderBuffer>& buffer);
  80
  81   void DecryptPendingBuffer();
  82
  83   // Callback for Decryptor::Decrypt().
  84   void DeliverBuffer(Decryptor::Status status,
  85                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  86
  87   // Callback for the |decryptor_| to notify this object that a new key has been
  88   // added.
  89   void OnKeyAdded();
  90
  91   // Resets decoder and calls |reset_cb_|.
  92   void DoReset();
  93
  94   // Returns Decryptor::StreamType converted from |stream_type_|.
  95   Decryptor::StreamType GetDecryptorStreamType() const;
  96
  97   // Creates and initializes either |audio_config_| or |video_config_| based on
  98   // |demuxer_stream_|.
  99   void InitializeDecoderConfig();
 100
 101   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 102
 103   State state_;
 104
 105   PipelineStatusCB init_cb_;
 106   ReadCB read_cb_;
 107   base::Closure reset_cb_;
 108   base::Closure waiting_for_decryption_key_cb_;
 109
 110   // Pointer to the input demuxer stream that will feed us encrypted buffers.
 111   DemuxerStream* demuxer_stream_;
 112
 113   AudioDecoderConfig audio_config_;
 114   VideoDecoderConfig video_config_;
 115
 116   // Callback to request/cancel decryptor creation notification.
 117   SetDecryptorReadyCB set_decryptor_ready_cb_;
 118
 119   Decryptor* decryptor_;
 120
 121   // The buffer returned by the demuxer that needs to be decrypted.
 122   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 123
 124   // Indicates the situation where new key is added during pending decryption
 125   // (in other words, this variable can only be set in state kPendingDecrypt).
 126   // If this variable is true and kNoKey is returned then we need to try
 127   // decrypting again in case the newly added key is the correct decryption key.
 128   bool key_added_while_decrypt_pending_;
 129
 130   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
 131   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
 132
 133   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 134 };
 135
 136 }  // namespace media
 137
 138 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_