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 class MediaLog;
  25
  26 // Decryptor-based DemuxerStream implementation that converts a potentially
  27 // encrypted demuxer stream to a clear demuxer stream.
  28 // All public APIs and callbacks are trampolined to the |task_runner_| so
  29 // that no locks are required for thread safety.
  30 class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
  31  public:
  32   DecryptingDemuxerStream(
  33       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  34       const scoped_refptr<MediaLog>& media_log,
  35       const SetDecryptorReadyCB& set_decryptor_ready_cb,
  36       const base::Closure& waiting_for_decryption_key_cb);
  37
  38   // Cancels all pending operations immediately and fires all pending callbacks.
  39   ~DecryptingDemuxerStream() override;
  40
  41   void Initialize(DemuxerStream* stream,
  42                   const PipelineStatusCB& status_cb);
  43
  44   // Cancels all pending operations and fires all pending callbacks. If in
  45   // kPendingDemuxerRead or kPendingDecrypt state, waits for the pending
  46   // operation to finish before satisfying |closure|. Sets the state to
  47   // kUninitialized if |this| hasn't been initialized, or to kIdle otherwise.
  48   void Reset(const base::Closure& closure);
  49
  50   // Returns the name of this class for logging purpose.
  51   std::string GetDisplayName() const;
  52
  53   // DemuxerStream implementation.
  54   void Read(const ReadCB& read_cb) override;
  55   AudioDecoderConfig audio_decoder_config() override;
  56   VideoDecoderConfig video_decoder_config() override;
  57   Type type() const override;
  58   Liveness liveness() const override;
  59   void EnableBitstreamConverter() override;
  60   bool SupportsConfigChanges() override;
  61   VideoRotation video_rotation() override;
  62
  63  private:
  64   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  65   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  66   // stabilizes.
  67   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  68   enum State {
  69     kUninitialized = 0,
  70     kDecryptorRequested,
  71     kIdle,
  72     kPendingDemuxerRead,
  73     kPendingDecrypt,
  74     kWaitingForKey
  75   };
  76
  77   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  78   // called when the decryptor has been completely attached to the pipeline.
  79   void SetDecryptor(Decryptor* decryptor,
  80                     const DecryptorAttachedCB& decryptor_attached_cb);
  81
  82   // Callback for DemuxerStream::Read().
  83   void DecryptBuffer(DemuxerStream::Status status,
  84                      const scoped_refptr<DecoderBuffer>& buffer);
  85
  86   void DecryptPendingBuffer();
  87
  88   // Callback for Decryptor::Decrypt().
  89   void DeliverBuffer(Decryptor::Status status,
  90                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  91
  92   // Callback for the |decryptor_| to notify this object that a new key has been
  93   // added.
  94   void OnKeyAdded();
  95
  96   // Resets decoder and calls |reset_cb_|.
  97   void DoReset();
  98
  99   // Returns Decryptor::StreamType converted from |stream_type_|.
 100   Decryptor::StreamType GetDecryptorStreamType() const;
 101
 102   // Creates and initializes either |audio_config_| or |video_config_| based on
 103   // |demuxer_stream_|.
 104   void InitializeDecoderConfig();
 105
 106   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 107
 108   scoped_refptr<MediaLog> media_log_;
 109
 110   State state_;
 111
 112   PipelineStatusCB init_cb_;
 113   ReadCB read_cb_;
 114   base::Closure reset_cb_;
 115   base::Closure waiting_for_decryption_key_cb_;
 116
 117   // Pointer to the input demuxer stream that will feed us encrypted buffers.
 118   DemuxerStream* demuxer_stream_;
 119
 120   AudioDecoderConfig audio_config_;
 121   VideoDecoderConfig video_config_;
 122
 123   // Callback to request/cancel decryptor creation notification.
 124   SetDecryptorReadyCB set_decryptor_ready_cb_;
 125
 126   Decryptor* decryptor_;
 127
 128   // The buffer returned by the demuxer that needs to be decrypted.
 129   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 130
 131   // Indicates the situation where new key is added during pending decryption
 132   // (in other words, this variable can only be set in state kPendingDecrypt).
 133   // If this variable is true and kNoKey is returned then we need to try
 134   // decrypting again in case the newly added key is the correct decryption key.
 135   bool key_added_while_decrypt_pending_;
 136
 137   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
 138   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
 139
 140   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 141 };
 142
 143 }  // namespace media
 144
 145 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_