/*  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>

#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 in the chain for MMF. Currently

 * they are:

 *

 * - MediaObject: a source of media

 * - AbstractEffect: supplying audio effects

 * - AudioOutput: pretty much a dummy interface, but is also MediaNode in order

 *   to simplify connection/disconnection.

 *

 * MediaNode provides spectatability into the chain, and also allows the

 * connection code to be written in a polymorphic manner, instead of putting it

 * all in the Backend class. Due to that MMF has no concept of chaining, the

 * order of the nodes in the graph has no meaning.

 */

class MediaNode : public QObject

{

    Q_OBJECT

public:

    MediaNode(QObject *parent);

    virtual bool connectMediaNode(MediaNode *target);

    virtual bool disconnectMediaNode(MediaNode *target);

    void setSource(MediaNode *source);

    MediaNode *source() const;

    MediaNode *target() const;

protected:

    /**

     * When connectMediaNode() is called and a MediaObject is part of

     * the its graph, this function will be called for each MediaNode in the

     * graph for which it hasn't been called yet.

     *

     * The caller guarantees that @p mo is always non-null.

     */

    virtual bool activateOnMediaObject(MediaObject *mo) = 0;

private:

    /**

     * Finds a MediaObject anywhere in the graph @p target is apart of, and

     * calls activateOnMediaObject() for all MediaNodes in the graph for which

     * it hasn't been applied to already.

     */

    bool applyNodesOnMediaObject(MediaNode *target);

    MediaNode * m_source;

    MediaNode * m_target;

    bool        m_isApplied;

};

}

}

QT_END_NAMESPACE

#endif