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      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_AUDIO_AUDIO_INPUT_IPC_H_
      6 #define MEDIA_AUDIO_AUDIO_INPUT_IPC_H_
      7 
      8 #include "base/memory/shared_memory.h"
      9 #include "base/sync_socket.h"
     10 #include "media/audio/audio_parameters.h"
     11 #include "media/base/media_export.h"
     12 
     13 namespace media {
     14 
     15 // Contains IPC notifications for the state of the server side
     16 // (AudioInputController) audio state changes and when an AudioInputController
     17 // has been created.  Implemented by AudioInputDevice.
     18 class MEDIA_EXPORT AudioInputIPCDelegate {
     19  public:
     20   // Valid states for the input stream.
     21   enum State {
     22     kRecording,
     23     kStopped,
     24     kError
     25   };
     26 
     27   // Called when an AudioInputController has been created.
     28   // The shared memory |handle| points to a memory section that's used to
     29   // transfer data between the AudioInputDevice and AudioInputController
     30   // objects.  The implementation of OnStreamCreated takes ownership.
     31   // The |socket_handle| is used by the AudioInputController to signal
     32   // notifications that more data is available and can optionally provide
     33   // parameter changes back.  The AudioInputDevice must read from this socket
     34   // and process the shared memory whenever data is read from the socket.
     35   virtual void OnStreamCreated(base::SharedMemoryHandle handle,
     36                                base::SyncSocket::Handle socket_handle,
     37                                int length,
     38                                int total_segments) = 0;
     39 
     40   // Called when state of an audio stream has changed.
     41   virtual void OnStateChanged(State state) = 0;
     42 
     43   // Called when the input stream volume has changed.
     44   virtual void OnVolume(double volume) = 0;
     45 
     46   // Called when the AudioInputIPC object is going away and/or when the
     47   // IPC channel has been closed and no more IPC requests can be made.
     48   // Implementations should delete their owned AudioInputIPC instance
     49   // immediately.
     50   virtual void OnIPCClosed() = 0;
     51 
     52  protected:
     53   virtual ~AudioInputIPCDelegate();
     54 };
     55 
     56 // Provides IPC functionality for an AudioInputIPCDelegate (e.g., an
     57 // AudioInputDevice).  The implementation should asynchronously deliver the
     58 // messages to an AudioInputController object (or create one in the case of
     59 // CreateStream()), that may live in a separate process.
     60 class MEDIA_EXPORT AudioInputIPC {
     61  public:
     62   virtual ~AudioInputIPC();
     63 
     64   // Sends a request to create an AudioInputController object in the peer
     65   // process, and configures it to use the specified audio |params|.  The
     66   // |total_segments| indidates number of equal-lengthed segments in the shared
     67   // memory buffer.  Once the stream has been created, the implementation will
     68   // notify |delegate| by calling OnStreamCreated().
     69   virtual void CreateStream(AudioInputIPCDelegate* delegate,
     70                             int session_id,
     71                             const AudioParameters& params,
     72                             bool automatic_gain_control,
     73                             uint32 total_segments) = 0;
     74 
     75   // Corresponds to a call to AudioInputController::Record() on the server side.
     76   virtual void RecordStream() = 0;
     77 
     78   // Sets the volume of the audio stream.
     79   virtual void SetVolume(double volume) = 0;
     80 
     81   // Closes the audio stream, which should shut down the corresponding
     82   // AudioInputController in the peer process.
     83   virtual void CloseStream() = 0;
     84 };
     85 
     86 }  // namespace media
     87 
     88 #endif  // MEDIA_AUDIO_AUDIO_INPUT_IPC_H_
     89