Chromecast: Add stream id interface in DecoderBufferBase class

chromecast/media/cma/base/decoder_buffer_adapter.h

 // Copyright 2014 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.
 
 #ifndef CHROMECAST_MEDIA_CMA_BASE_DECODER_BUFFER_ADAPTER_H_
 #define CHROMECAST_MEDIA_CMA_BASE_DECODER_BUFFER_ADAPTER_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chromecast/media/cma/base/decoder_buffer_base.h"
 
 namespace media {
 class DecoderBuffer;
 }
 
 namespace chromecast {
 namespace media {
 
 // DecoderBufferAdapter wraps a ::media::DecoderBuffer
 // into a DecoderBufferBase.
 class DecoderBufferAdapter : public DecoderBufferBase {
  public:
   explicit DecoderBufferAdapter(

[gunsch, 2015/05/21 21:06:34]

why not just change the primary ctor instead of having two ctors?

[erickung1, 2015/05/21 21:38:34]

I found out some test code and component which doesn't really require stream_id
in the decoder buffer. It makes thing odd to force all of them adding something
like new DecoderBufferAdapter(-1, buffer) in the code

But Please let me know. I don't have strong opinion on both solutions.

       const scoped_refptr< ::media::DecoderBuffer>& buffer);
+  DecoderBufferAdapter(
+      int type, const scoped_refptr< ::media::DecoderBuffer>& buffer);

[gunsch, 2015/05/21 21:06:34]

type --> stream_id

[erickung1, 2015/05/21 21:38:34]

Done.

 
   // DecoderBufferBase implementation.
+  int stream_id() const override;

[gunsch, 2015/05/21 21:06:34]

what values can a stream_id have?

if only 2-3 possible values, could this be an enum?

[erickung1, 2015/05/21 21:38:34]

we'll use two possible value.
However, I think about leaving it more flexible which can be scale later on. 

[gunsch, 2015/05/21 21:45:29]

what is inflexible about enum? you can always add more enum values...

"-1" has no inherently semantic indication as far as "stream ids" go, so it's
completely unclear to the reader what it means when seeing it in the code.
Having "-1" littered around the code seems like a pretty clear anti-pattern.

[erickung1, 2015/05/21 23:32:21]

Make sense. I change the type to enum

   base::TimeDelta timestamp() const override;
   const uint8* data() const override;
   uint8* writable_data() const override;
   size_t data_size() const override;
   const ::media::DecryptConfig* decrypt_config() const override;
   bool end_of_stream() const override;
 
  private:
   ~DecoderBufferAdapter() override;
 
+  int stream_id_;
   scoped_refptr< ::media::DecoderBuffer> const buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(DecoderBufferAdapter);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_BASE_DECODER_BUFFER_ADAPTER_H_