Encrypted Media: DecryptingXxx::SetDecryptor() accepts NULL decryptor.

media/filters/decrypting_audio_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/filters/decrypting_audio_decoder.h"
 
 #include <cstdlib>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 155 matching lines @@
 }
 
 void DecryptingAudioDecoder::SetDecryptor(Decryptor* decryptor) {
   DVLOG(2) << "SetDecryptor()";
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kDecryptorRequested) << state_;
   DCHECK(!init_cb_.is_null());
   DCHECK(!set_decryptor_ready_cb_.is_null());
 
   set_decryptor_ready_cb_.Reset();
+
+  if (!decryptor) {
+    base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
+    state_ = kDecodeFinished;

[qinmin, 2013/06/18 22:09:20]

why the state_ value is different between DecryptingAudioDecoder and
DecryptingVideoDecoder

[xhwang, 2013/06/18 22:34:23]

The classic answer is "for historical reasons".

Long story: It used to be kDecodeFinished in both which inherited it from
FFmpegVideoDecodre. Then when I was refactoring the video path in media
pipeline, I added kError in VideoDecoders because that makes more sense. Audio
path, however, is not updated yet. I don't intent to refactor the audio path
right now and would like to just follow what the current code is doing.

[ddorwin, 2013/06/19 00:06:50]

Do we have a bug tracking this?

[xhwang, 2013/06/19 00:37:45]

Done.

+    return;
+  }
+
   decryptor_ = decryptor;
 
   const AudioDecoderConfig& input_config =
       demuxer_stream_->audio_decoder_config();
   AudioDecoderConfig config;
   config.Initialize(input_config.codec(),
                     kSampleFormatS16,
                     input_config.channel_layout(),
                     input_config.samples_per_second(),
                     input_config.extra_data(),
@@ skipping 292 matching lines @@
 
 base::TimeDelta DecryptingAudioDecoder::NumberOfSamplesToDuration(
     int number_of_samples) const {
   DCHECK(samples_per_second_);
   return base::TimeDelta::FromMicroseconds(base::Time::kMicrosecondsPerSecond *
                                            number_of_samples /
                                            samples_per_second_);
 }
 
 }  // namespace media