Prevent a voice channel from sending data before a renderer is set.

webrtc/media/base/audiosource.h

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_MEDIA_BASE_AUDIORENDERER_H_
-#define WEBRTC_MEDIA_BASE_AUDIORENDERER_H_
+#ifndef WEBRTC_MEDIA_BASE_AUDIOSOURCE_H_

[the sun, 2016/03/03 15:15:24]

I like this change because I've always found this name confusing.

However, the change means we now have webrtc::AudioSourceInterface and
cricket::AudioSource, which is a bit confusing. Especially given that this class
should likely be a pure interface and following naming conventions it should
then be called cricket::AudioSourceInterface.

See:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/webrtc...

One way to mitigate any confusion would be to call the MediaSourceInterface
descendant AudioMediaSourceInterface (or AudioMediaSource, since it is not
purely abstract); video would have to follow. Another way would be to be more
explicit about the use of namespaces; the border between cricket and webrtc is a
bit blurry.

[Taylor Brandstetter, 2016/03/04 16:06:56]

I wish we could just get rid of this class and use AudioSourceInterface
everywhere. But what this class provides is a separate "OnClose" method which is
protected by a critical section in the implementation, and we probably can't get
rid of that. Maybe the solution is to add OnClose to AudioSinkInterface, and
when it's implemented everywhere, switch over to that. But for now, I'll try to
think of a better name.

+#define WEBRTC_MEDIA_BASE_AUDIOSOURCE_H_
 
 #include <cstddef>
 
 namespace cricket {
 
-// Abstract interface for rendering the audio data.
-class AudioRenderer {
+// Abstract interface for providing the audio data.
+class AudioSource {
  public:
   class Sink {
    public:
-    // Callback to receive data from the AudioRenderer.
+    // Callback to receive data from the AudioSource.
     virtual void OnData(const void* audio_data,
                         int bits_per_sample,
                         int sample_rate,
                         size_t number_of_channels,
                         size_t number_of_frames) = 0;
 
-    // Called when the AudioRenderer is going away.
+    // Called when the AudioSource is going away.
     virtual void OnClose() = 0;
 
    protected:
     virtual ~Sink() {}
   };
 
-  // Sets a sink to the AudioRenderer. There can be only one sink connected
-  // to the renderer at a time.
+  // Sets a sink to the AudioSource. There can be only one sink connected
+  // to the source at a time.
   virtual void SetSink(Sink* sink) {}

[the sun, 2016/03/03 15:15:24]

= 0

[Taylor Brandstetter, 2016/03/04 16:06:56]

Done.

 
  protected:
-  virtual ~AudioRenderer() {}
+  virtual ~AudioSource() {}
 };
 
 }  // namespace cricket
 
-#endif  // WEBRTC_MEDIA_BASE_AUDIORENDERER_H_
+#endif  // WEBRTC_MEDIA_BASE_AUDIOSOURCE_H_