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// Copyright (c) 2011 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 CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
#define CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
#pragma once
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/threading/thread.h"
template <typename T> struct DefaultSingletonTraits;
namespace chromeos {
class AudioMixer;
class AudioHandler {
public:
static void Initialize();
static void Shutdown();
// GetInstance returns NULL if not initialized or if already shutdown.
static AudioHandler* GetInstance();
// Is the mixer initialized?
// TODO(derat): All of the volume-percent methods will produce "interesting"
// results before the mixer is initialized, since the driver's volume range
// isn't known at that point. This could be avoided if AudioMixer objects
// instead took percentages and did their own conversions to decibels.
bool IsInitialized();
// Gets volume level in our internal 0-100% range, 0 being pure silence.
double GetVolumePercent();
// Sets volume level from 0-100%.
void SetVolumePercent(double volume_percent);
// Adjusts volume up (positive percentage) or down (negative percentage).
void AdjustVolumeByPercent(double adjust_by_percent);
// Is the volume currently muted?
bool IsMuted();
// Mutes or unmutes all audio.
void SetMuted(bool do_mute);
private:
// Defines the delete on exit Singleton traits we like. Best to have this
// and constructor/destructor private as recommended for Singletons.
friend struct DefaultSingletonTraits<AudioHandler>;
AudioHandler();
virtual ~AudioHandler();
// Conversion between our internal scaling (0-100%) and decibels.
double VolumeDbToPercent(double volume_db) const;
double PercentToVolumeDb(double volume_percent) const;
scoped_ptr<AudioMixer> mixer_;
DISALLOW_COPY_AND_ASSIGN(AudioHandler);
};
} // namespace chromeos
DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::AudioHandler);
#endif // CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
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