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// Copyright 2014 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 DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_
#define DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_
#include <stdint.h>
#include <string>
#include <vector>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "device/bluetooth/bluetooth_export.h"
namespace device {
// TODO(mcchou): Define a BluetoothAudioSink specific IOBuffer abstraction.
// BluetoothAudioSink represents a local A2DP audio sink where a remote device
// can stream audio data. Once a BluetoothAudioSink is successfully registered,
// user applications can obtain a pointer to a BluetoothAudioSink object via
// the interface provided by BluetoothAdapter. The validity of a
// BluetoothAudioSink depends on whether BluetoothAdapter is present and whether
// it is powered.
class DEVICE_BLUETOOTH_EXPORT BluetoothAudioSink
: public base::RefCounted<BluetoothAudioSink> {
public:
// Possible values indicating the connection states between the
// BluetoothAudioSink and the remote device.
enum State {
STATE_INVALID, // BluetoothAdapter not presented or not powered.
STATE_DISCONNECTED, // Not connected.
STATE_IDLE, // Connected but not streaming.
STATE_PENDING, // Connected, streaming but not acquired.
STATE_ACTIVE, // Connected, streaming and acquired.
};
// Possible types of error raised by Audio Sink object.
enum ErrorCode {
ERROR_UNSUPPORTED_PLATFORM, // A2DP sink not supported on current platform.
ERROR_INVALID_ADAPTER, // BluetoothAdapter not present/powered.
ERROR_NOT_REGISTERED, // BluetoothAudioSink not registered.
ERROR_NOT_UNREGISTERED, // BluetoothAudioSink not unregistered.
};
// Options to configure an A2DP audio sink.
struct Options {
Options();
~Options();
uint8_t codec;
std::vector<uint8_t> capabilities;
};
// Interface for observing changes from a BluetoothAudioSink.
class Observer {
public:
virtual ~Observer() {}
// Called when the state of the BluetoothAudioSink object is changed.
// |audio_sink| indicates the object being changed, and |state| indicates
// the new state of that object.
virtual void BluetoothAudioSinkStateChanged(
BluetoothAudioSink* audio_sink,
BluetoothAudioSink::State state) = 0;
// Called when the volume of the BluetoothAudioSink object is changed.
// |audio_sink| indicates the object being changed, and |volume| indicates
// the new volume level of that object.
virtual void BluetoothAudioSinkVolumeChanged(
BluetoothAudioSink* audio_sink,
uint16_t volume) = 0;
// Called when there is audio data available. |audio_sink| indicates the
// object being changed. |data| is the pointer to the audio data and |size|
// is the number of bytes in |data|. |read_mtu| is the max size of the RTP
// packet. This method provides the raw audio data which hasn't been
// processed, so RTP assembling and SBC decoding need to be handled in order
// to get PCM data.
virtual void BluetoothAudioSinkDataAvailable(BluetoothAudioSink* audio_sink,
char* data,
size_t size,
uint16_t read_mtu) = 0;
};
// The ErrorCallback is used for the methods that can fail in which case it
// is called.
typedef base::Callback<void(ErrorCode)> ErrorCallback;
// Possible volumes for media transport are 0-127, and 128 is used to
// represent invalid volume.
static const uint16_t kInvalidVolume;
// Unregisters the audio sink. An audio sink will unregister itself
// automatically in its destructor, but calling Unregister is recommended,
// since user applications can be notified of an error returned by the call.
virtual void Unregister(const base::Closure& callback,
const ErrorCallback& error_callback) = 0;
// Adds and removes an observer for events on the BluetoothAudioSink object.
// If monitoring multiple audio sinks, check the |audio_sink| parameter of
// observer methods to determine which audio sink is issuing the event.
virtual void AddObserver(Observer* observer) = 0;
virtual void RemoveObserver(Observer* observer) = 0;
// Getters for state and volume.
virtual State GetState() const = 0;
// Returns the current volume level of the audio sink. The valid volumes are
// 0-127, and |kInvalidVolume| is returned instead if the volume is unknown.
virtual uint16_t GetVolume() const = 0;
protected:
friend class base::RefCounted<BluetoothAudioSink>;
BluetoothAudioSink();
// The destructor invokes Unregister() to ensure the audio sink will be
// unregistered even if the user applications fail to do so.
virtual ~BluetoothAudioSink();
private:
DISALLOW_COPY_AND_ASSIGN(BluetoothAudioSink);
};
} // namespace device
#endif // DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_
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