GeoTagWriter.h

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//
// This file is part of the Marble Virtual Globe.
//
// This program is free software licensed under the GNU LGPL. You can
// find a copy of this license in LICENSE.txt in the top directory of
// the source code.
//
// Copyright 2009      Andrew Manson <g.real.ate@gmail.com>
// Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
//

#ifndef MARBLE_GEOTAGWRITER_H
#define MARBLE_GEOTAGWRITER_H

#include <QPair>
#include <QHash>

namespace Marble
{

class GeoDataObject;
class GeoNode;
class GeoWriter;

class GeoTagWriter
{
public:
    virtual bool write( const GeoNode *node, GeoWriter& writer ) const = 0;

    typedef QPair<QString, QString> QualifiedName;

protected:
    GeoTagWriter();
    virtual ~GeoTagWriter();

    bool writeElement( const GeoNode* object, GeoWriter& writer ) const;

private:
    // Only our registrar is allowed to register tag writers.
    friend struct GeoTagWriterRegistrar;
    static void registerWriter(const QualifiedName&, const GeoTagWriter*);

private:
    //Collect the Tag Writers and provide a singleton like accessor
    typedef QHash<QualifiedName, const GeoTagWriter*> TagHash;
    static TagHash* tagWriterHash();

private:
    // Only our writer is allowed to access tag handlers.
    friend class GeoWriter;
    static const GeoTagWriter* recognizes(const QualifiedName&);
};

// Helper structure
struct GeoTagWriterRegistrar
{
public:
    GeoTagWriterRegistrar(const GeoTagWriter::QualifiedName& name, const GeoTagWriter* writer)
    {
        GeoTagWriter::registerWriter(name, writer);
    }
};

}

#endif