media/filters/decrypting_audio_decoder.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_AUDIO_DECODER_H_
   6 #define MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/time/time.h"
  13 #include "media/base/audio_decoder.h"
  14 #include "media/base/decryptor.h"
  15 #include "media/base/demuxer_stream.h"
  16
  17 namespace base {
  18 class SingleThreadTaskRunner;
  19 }
  20
  21 namespace media {
  22
  23 class AudioTimestampHelper;
  24 class DecoderBuffer;
  25 class Decryptor;
  26 class MediaLog;
  27
  28 // Decryptor-based AudioDecoder implementation that can decrypt and decode
  29 // encrypted audio buffers and return decrypted and decompressed audio frames.
  30 // All public APIs and callbacks are trampolined to the |task_runner_| so
  31 // that no locks are required for thread safety.
  32 class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
  33  public:
  34   DecryptingAudioDecoder(
  35       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  36       const scoped_refptr<MediaLog>& media_log,
  37       const SetDecryptorReadyCB& set_decryptor_ready_cb,
  38       const base::Closure& waiting_for_decryption_key_cb);
  39   ~DecryptingAudioDecoder() override;
  40
  41   // AudioDecoder implementation.
  42   std::string GetDisplayName() const override;
  43   void Initialize(const AudioDecoderConfig& config,
  44                   const InitCB& init_cb,
  45                   const OutputCB& output_cb) override;
  46   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  47               const DecodeCB& decode_cb) override;
  48   void Reset(const base::Closure& closure) override;
  49
  50  private:
  51   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  52   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  53   // stabilizes.
  54   // TODO(xhwang): Update this diagram for DecryptingAudioDecoder.
  55   enum State {
  56     kUninitialized = 0,
  57     kDecryptorRequested,
  58     kPendingDecoderInit,
  59     kIdle,
  60     kPendingDecode,
  61     kWaitingForKey,
  62     kDecodeFinished,
  63     kError
  64   };
  65
  66   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  67   // called when the decryptor has been completely attached to the pipeline.
  68   void SetDecryptor(Decryptor* decryptor,
  69                     const DecryptorAttachedCB& decryptor_attached_cb);
  70
  71   // Initializes the audio decoder on the |decryptor_| with |config_|.
  72   void InitializeDecoder();
  73
  74   // Callback for Decryptor::InitializeAudioDecoder() during initialization.
  75   void FinishInitialization(bool success);
  76
  77   void DecodePendingBuffer();
  78
  79   // Callback for Decryptor::DecryptAndDecodeAudio().
  80   void DeliverFrame(int buffer_size,
  81                     Decryptor::Status status,
  82                     const Decryptor::AudioFrames& frames);
  83
  84   // Callback for the |decryptor_| to notify this object that a new key has been
  85   // added.
  86   void OnKeyAdded();
  87
  88   // Resets decoder and calls |reset_cb_|.
  89   void DoReset();
  90
  91   // Sets timestamps for |frames| and then passes them to |output_cb_|.
  92   void ProcessDecodedFrames(const Decryptor::AudioFrames& frames);
  93
  94   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  95
  96   scoped_refptr<MediaLog> media_log_;
  97
  98   State state_;
  99
 100   InitCB init_cb_;
 101   OutputCB output_cb_;
 102   DecodeCB decode_cb_;
 103   base::Closure reset_cb_;
 104   base::Closure waiting_for_decryption_key_cb_;
 105
 106   // The current decoder configuration.
 107   AudioDecoderConfig config_;
 108
 109   // Callback to request/cancel decryptor creation notification.
 110   SetDecryptorReadyCB set_decryptor_ready_cb_;
 111
 112   Decryptor* decryptor_;
 113
 114   // The buffer that needs decrypting/decoding.
 115   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
 116
 117   // Indicates the situation where new key is added during pending decode
 118   // (in other words, this variable can only be set in state kPendingDecode).
 119   // If this variable is true and kNoKey is returned then we need to try
 120   // decrypting/decoding again in case the newly added key is the correct
 121   // decryption key.
 122   bool key_added_while_decode_pending_;
 123
 124   scoped_ptr<AudioTimestampHelper> timestamp_helper_;
 125
 126   base::WeakPtr<DecryptingAudioDecoder> weak_this_;
 127   base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_;
 128
 129   DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
 130 };
 131
 132 }  // namespace media
 133
 134 #endif  // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_