output_observer.h

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/*
 * Copyright © 2014 Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authored by: Thomas Voß <thomas.voss@canonical.com>
 */
#ifndef CORE_UBUNTU_MEDIA_AUDIO_OUTPUT_OBSERVER_H_
#define CORE_UBUNTU_MEDIA_AUDIO_OUTPUT_OBSERVER_H_
 
#include <core/property.h>
 
#include <iosfwd>
#include <memory>
 
namespace core
{
namespace ubuntu
{
namespace media
{
namespace audio
{
// All known states of an audio output.
enum class OutputState
{
    // The output is via a private earpiece (i.e. headphones, headset)
    Earpiece,
    // The output is via the internal speaker.
    Speaker,
    // The output is via an external device (a2dp, etc)
    External,
};
 
// Models observation of audio outputs of a device.
// Right now, we are only interested in monitoring the
// state of external outputs to react accordingly if
// wired or bluetooth outputs are connected/disconnected.
class OutputObserver
{
public:
    // Save us some typing.
    typedef std::shared_ptr<OutputObserver> Ptr;
 
    virtual ~OutputObserver() = default;
 
    // Getable/observable property holding the state of external outputs.
    virtual const core::Property<OutputState>& external_output_state() const = 0;
 
protected:
    OutputObserver() = default;
    OutputObserver(const OutputObserver&) = delete;
    OutputObserver& operator=(const OutputObserver&) = delete;
};
 
// Pretty prints the given state to the given output stream.
std::ostream& operator<<(std::ostream&, OutputState);
 
// Creats a platform default instance for observing audio outputs.
OutputObserver::Ptr make_platform_default_output_observer();
}
}
}
}
 
#endif // CORE_UBUNTU_MEDIA_AUDIO_OUTPUT_OBSERVER_H_