media/mojo/interfaces/audio_logging.mojom

// Copyright 2018 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.

module media.mojom;

import "media/mojo/interfaces/audio_parameters.mojom";

// This interface is implemented by the browser process to log state information
// about an active audio component.
interface AudioLog {
  // Called when an audio component is created.  |params| are the parameters of
  // the created stream.  |device_id| is the id of the audio device opened by
  // the created stream.
  OnCreated(media.mojom.AudioParameters params,
            string device_id);

  // Called when an audio component is started, generally this is synonymous
  // with "playing."
  OnStarted();

  // Called when an audio component is stopped, generally this is synonymous
  // with "paused."
  OnStopped();

  // Called when an audio component is closed, generally this is synonymous
  // with "deleted."
  OnClosed();

  // Called when an audio component encounters an error.
  OnError();

  // Called when an audio component changes volume.  |volume| is the new volume.
  OnSetVolume(double volume);

  // Called with information about audio processing set-up for an audio
  // component.
  OnProcessingStateChanged(string message);

  // Called when an audio component wants to forward a log message.
  OnLogMessage(string message);
};

enum AudioLogComponent {
  kInputController,
  kOutputController,
  kOutputStream,
};

// This interface is implemented by the browser process to allow clients to
// create AudioLog instances for tracking the behavior of an audio component.
// The only client for this interface is the audio service.
interface AudioLogFactory {
  // Creates an AudioLog object for tracking the behavior for one instance of
  // the given |component|.  Each instance of an "owning" class must create its
  // own AudioLog. The created AudioLog object is bound to |audio_log_request|.
  CreateAudioLog(AudioLogComponent component,
                 int32 component_id,
                 AudioLog& audio_log_request);
};