RefCounted types should not have public destructors, delegate cleanup

media/audio/audio_io.h

 // 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_IO_H_
 #define MEDIA_AUDIO_AUDIO_IO_H_
 
 #include "base/basictypes.h"
 #include "media/audio/audio_buffers_state.h"
 
@@ skipping 38 matching lines @@
 namespace media {
 
 class MEDIA_EXPORT AudioOutputStream {
  public:
   // Audio sources must implement AudioSourceCallback. This interface will be
   // called in a random thread which very likely is a high priority thread. Do
   // not rely on using this thread TLS or make calls that alter the thread
   // itself such as creating Windows or initializing COM.
   class MEDIA_EXPORT AudioSourceCallback {
    public:
-    virtual ~AudioSourceCallback() {}
-
     // Provide more data by filling |dest| up to |max_size| bytes. The provided
     // buffer size is determined by the |samples_per_packet| specified in
     // AudioParameters when the stream is created. The source will return
     // the number of bytes it filled. The expected structure of |dest| is
     // platform and format specific.
     // |buffers_state| contains current state of the buffers, and can be used
     // by the source to calculate delay.
     virtual uint32 OnMoreData(uint8* dest,
                               uint32 max_size,
                               AudioBuffersState buffers_state) = 0;
 
     // There was an error while playing a buffer. Audio source cannot be
     // destroyed yet. No direct action needed by the AudioStream, but it is
     // a good place to stop accumulating sound data since is is likely that
     // playback will not continue. |code| is an error code that is platform
     // specific.
     virtual void OnError(AudioOutputStream* stream, int code) = 0;
 
     // Waits till data becomes available. Used when buffering data starting
     // new audio stream.
     // Polling is not the best approach, but incorporating messaging loop
     // with delayed tasks into guts of complex code is even worse, as it is
     // very error-prone. We cannot easily add synchronization, interface is
     // already cut in stone because of need of backward compatibility with
     // plugins. In any case, data is usually immediately available,
     // so there would be no delay.
     virtual void WaitTillDataReady() {}
+
+   protected:
+    virtual ~AudioSourceCallback() {}
   };
 
   virtual ~AudioOutputStream() {}
 
   // Open the stream. false is returned if the stream cannot be opened.
   virtual bool Open() = 0;
 
   // Starts playing audio and generating AudioSourceCallback::OnMoreData().
   // Since implementor of AudioOutputStream may have internal buffers, right
   // after calling this method initial buffers are fetched.
@@ skipping 14 matching lines @@
   // Close the stream. This also generates AudioSourceCallback::OnClose().
   // After calling this method, the object should not be used anymore.
   virtual void Close() = 0;
 };
 
 // Models an audio sink receiving recorded audio from the audio driver.
 class MEDIA_EXPORT AudioInputStream {
  public:
   class MEDIA_EXPORT AudioInputCallback {
    public:
-    virtual ~AudioInputCallback() {}
-
     // Called by the audio recorder when a full packet of audio data is
     // available. This is called from a special audio thread and the
     // implementation should return as soon as possible.
     virtual void OnData(AudioInputStream* stream, const uint8* src,
                         uint32 size, uint32 hardware_delay_bytes,
                         double volume) = 0;
 
     // The stream is done with this callback, the last call received by this
     // audio sink.
     virtual void OnClose(AudioInputStream* stream) = 0;
 
     // There was an error while recording audio. The audio sink cannot be
     // destroyed yet. No direct action needed by the AudioInputStream, but it
     // is a good place to stop accumulating sound data since is is likely that
     // recording will not continue. |code| is an error code that is platform
     // specific.
     virtual void OnError(AudioInputStream* stream, int code) = 0;
+
+   protected:
+    virtual ~AudioInputCallback() {}
   };
 
   virtual ~AudioInputStream() {}
 
   // Open the stream and prepares it for recording. Call Start() to actually
   // begin recording.
   virtual bool Open() = 0;
 
   // Starts recording audio and generating AudioInputCallback::OnData().
   // The input stream does not take ownership of this callback.
@@ skipping 21 matching lines @@
   // Sets the Automatic Gain Control (AGC) state.
   virtual void SetAutomaticGainControl(bool enabled) = 0;
 
   // Returns the Automatic Gain Control (AGC) state.
   virtual bool GetAutomaticGainControl() = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_IO_H_