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// Copyright 2017 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_SYSTEM_H_
#define MEDIA_AUDIO_AUDIO_SYSTEM_H_
#include <string>
#include "base/callback.h"
#include "media/audio/audio_device_description.h"
#include "media/base/audio_parameters.h"
#include "media/base/media_export.h"
namespace base {
class SingleThreadTaskRunner;
}
namespace media {
class AudioManager;
// Work in progress: Provides asynchronous interface to AudioManager. All the
// AudioManager clients will be switched to it, in preparation for moving
// to Mojo audio service.
class MEDIA_EXPORT AudioSystem {
public:
// Replies are asynchronously sent from audio system thread to the thread the
// call is issued on. Attention! Audio system thread may outlive the client
// objects; bind callbacks with care.
using OnAudioParamsCallback =
base::OnceCallback<void(const AudioParameters&)>;
using OnBoolCallback = base::OnceCallback<void(bool)>;
using OnDeviceDescriptionsCallback =
base::OnceCallback<void(AudioDeviceDescriptions)>;
using OnDeviceIdCallback = base::OnceCallback<void(const std::string&)>;
using OnInputDeviceInfoCallback = base::OnceCallback<
void(const AudioParameters&, const AudioParameters&, const std::string&)>;
// Must not be called on audio system thread if it differs from the one
// AudioSystem is destroyed on. See http://crbug.com/705455.
static AudioSystem* Get();
virtual ~AudioSystem();
// Callback may receive invalid parameters, it means the specified device is
// not found. This is best-effort: valid parameters do not guarantee existance
// of the device.
// TODO(olka,tommi): fix all AudioManager implementations to return invalid
// parameters if the device is not found.
virtual void GetInputStreamParameters(
const std::string& device_id,
OnAudioParamsCallback on_params_cb) const = 0;
// If media::AudioDeviceDescription::IsDefaultDevice(device_id) is true,
// callback will receive the parameters of the default output device.
// Callback may receive invalid parameters, it means the specified device is
// not found. This is best-effort: valid parameters do not guarantee existance
// of the device.
// TODO(olka,tommi): fix all AudioManager implementations to return invalid
// parameters if the device is not found.
virtual void GetOutputStreamParameters(
const std::string& device_id,
OnAudioParamsCallback on_params_cb) const = 0;
virtual void HasInputDevices(OnBoolCallback on_has_devices_cb) const = 0;
virtual void HasOutputDevices(OnBoolCallback on_has_devices_cb) const = 0;
// Replies with device descriptions of input audio devices if |for_input| is
// true, and of output audio devices otherwise.
virtual void GetDeviceDescriptions(
OnDeviceDescriptionsCallback on_descriptions_cb,
bool for_input) = 0;
// Replies with an empty string if there is no associated output device found.
virtual void GetAssociatedOutputDeviceID(
const std::string& input_device_id,
OnDeviceIdCallback on_device_id_cb) = 0;
// Replies with audio parameters for the specified input device and audio
// parameters and device ID of the associated output device, if any (otherwise
// it's AudioParameters() and an empty string).
virtual void GetInputDeviceInfo(
const std::string& input_device_id,
OnInputDeviceInfoCallback on_input_device_info_cb) = 0;
virtual base::SingleThreadTaskRunner* GetTaskRunner() const = 0;
protected:
// Sets the global AudioSystem pointer to the specified non-null value.
static void SetInstance(AudioSystem* audio_system);
// Sets the global AudioSystem pointer to null if it equals the specified one.
static void ClearInstance(const AudioSystem* audio_system);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_SYSTEM_H_
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