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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 AudioHandler* GetInstance();
// Get volume level in our internal 0-100% range, 0 being pure silence.
// Returns default of 0 on error. This function will block until the volume
// is retrieved or fails. Blocking call.
double GetVolumePercent();
// Set volume level from 0-100%. Volumes above 100% are OK and boost volume,
// although clipping will occur more at higher volumes. Volume gets quieter
// as the percentage gets lower, and then switches to silence at 0%.
void SetVolumePercent(double volume_percent);
// Adjust volume up (positive percentage) or down (negative percentage),
// capping at 100%. GetVolumePercent() will be accurate after this
// blocking call.
void AdjustVolumeByPercent(double adjust_by_percent);
// Just returns true if mute, false if not or an error occurred.
// Blocking call.
bool IsMute();
// Mutes all audio. Non-blocking call.
void SetMute(bool do_mute);
// Disconnects from mixer. Called during shutdown.
void Disconnect();
private:
enum MixerType {
MIXER_TYPE_ALSA = 0,
MIXER_TYPE_NONE,
};
// 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>;
// Connect to the current mixer_type_.
bool TryToConnect(bool async);
void OnMixerInitialized(bool success);
AudioHandler();
virtual ~AudioHandler();
bool VerifyMixerConnection();
// 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_;
bool connected_;
int reconnect_tries_;
// The min and max volume in decibels, limited to the maximum range of the
// audio system being used.
double max_volume_db_;
double min_volume_db_;
// Which mixer is being used, ALSA or none.
MixerType mixer_type_;
DISALLOW_COPY_AND_ASSIGN(AudioHandler);
};
} // namespace chromeos
DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::AudioHandler);
#endif // CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
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