/*  This file is part of the KDE project.

Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

This library is free software: you can redistribute it and/or modify

it under the terms of the GNU Lesser General Public License as published by

the Free Software Foundation, either version 2.1 or 3 of the License.

This library 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 library.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef PHONON_MMF_MEDIANODE_H

#define PHONON_MMF_MEDIANODE_H

#include <QObject>

#include <phonon/effectinterface.h>

#include "audioplayer.h"

QT_BEGIN_NAMESPACE

/**

 * @file mmf_medianode.h mmf_medianode.cpp

 *

 * This file starts with mmf_ in order to avoid clash with Phonon's

 * medianode.h. The GStreamer backend has a file named medianode.h, but it

 * isn't compiled with ABLD build system, which have problems with separating

 * user and system include paths.

 */

namespace Phonon

{

namespace MMF

{

class MediaObject;

/**

 * @short Base class for all nodes in the MMF backend.

 *

 * MediaNode is the base class for all nodes created by the MMF

 * backend.

 *

 * These nodes may be one of the following types:

 *

 * - MediaObject

 *      This represents the source of media data.  It encapsulates the

 *      appropriate MMF client API for playing audio or video.

 * - AudioOutput

 *      This represents the audio output device.  Since the MMF client API

 *      does not expose the output device directly, this backend node

 *      simply forwards volume control commands to the MediaObject.

 * - VideoWidget

 *      A native widget on which video will be rendered.

 * - An audio effect, derived form AbstractAudioEffect

 *

 * Because the MMF API does not support the concept of a media filter graph,

 * this class must ensure the following:

 *

 * - Each media graph contains at most one MediaObject instance.

 * - Every non-MediaObject node holds a reference to the MediaObject.  This

 * allows commands to be sent through the graph to the encapsulated MMF client

 * API.

 */

class MediaNode : public QObject

{

    Q_OBJECT

public:

    MediaNode(QObject *parent);

    ~MediaNode();

    bool connectOutput(MediaNode *output);

    bool disconnectOutput(MediaNode *output);

    virtual void connectMediaObject(MediaObject *mediaObject) = 0;

    virtual void disconnectMediaObject(MediaObject *mediaObject) = 0;

private:

    bool isMediaObject() const;

    void updateMediaObject();

    void setMediaObject(MediaObject *mediaObject);

    typedef QList<const MediaNode *> NodeList;

    void visit(QList<MediaNode *>& visited, MediaObject*& mediaObject);

private:

    MediaObject *       m_mediaObject;

    // All nodes except MediaObject may have an input

    MediaNode *         m_input;

    // Only MediaObject can have more than one output

    QList<MediaNode *>  m_outputs;

};

}

}

QT_END_NAMESPACE

#endif