/***************************************************************************
*   Copyright (C) 2009 by Rajko Albrecht  ral@alwins-world.de             *
*   http://kdesvn.alwins-world.de/                                        *
*                                                                         *
* 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 of the License, or (at your option) any later version.      *
*                                                                         *
* 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 (in the file LGPL.txt); if not,         *
* write to the Free Software Foundation, Inc., 51 Franklin St,            *
* Fifth Floor, Boston, MA  02110-1301  USA                                *
***************************************************************************/
/*
 *  Ideas, algorithm and code taken from KDE libraries
 */

#ifndef CONVERSION_CHECK_H
#define CONVERSION_CHECK_H

#include <QtCore/QString>
#include <QtGui/QColor>
#include <QtGui/QFont>
#include <QtCore/QDate>
#include <QtCore/QPoint>
#include <QtCore/QSize>
#include <QtCore/QRect>
#include <QtCore/QVariant>

namespace svn
{
namespace ConversionCheck
{

// used to distinguish between supported/unsupported types
struct supported { };
struct unsupported { };

// traits type class to define support for constraints
template <typename T>
struct QVconvertible {
    typedef unsupported toQString;
    typedef unsupported toQVariant;
};

// constraint classes
template <typename T>
struct type_toQString {
    void constraint()
    {
        supported x = y;
    }
    typename QVconvertible<T>::toQString y;
};

template <typename T>
struct type_toQVariant {
    void constraint()
    {
        supported x = y;
    }
    typename QVconvertible<T>::toQVariant y;
};

// check if T is convertible to QString thru QVariant
// if not supported can't be used in QList<T> functions
template <typename T>
inline void to_QString()
{
    void (type_toQString<T>::*x)() = &type_toQString<T>::constraint;
    Q_UNUSED(x);
}

// check if T is convertible to QVariant & supported in readEntry/writeEntry
template <typename T>
inline void to_QVariant()
{
    void (type_toQVariant<T>::*x)() = &type_toQVariant<T>::constraint;
    Q_UNUSED(x);
}

// define for all types handled in readEntry/writeEntry
// string_support - is supported by QVariant(type).toString(),
//                  can be used in QList<T> functions
// variant_support - has a QVariant constructor
#define QVConversions(type, string_support, variant_support) \
    template <> struct QVconvertible<type> {\
        typedef string_support toQString;\
        typedef variant_support toQVariant;\
    }

// The only types needed here are the types handled in readEntry/writeEntry
// the default QVconvertible will take care of the rest.
QVConversions(bool, supported, supported);
QVConversions(int, supported, supported);
QVConversions(unsigned int, supported, supported);
QVConversions(long long, supported, supported);
QVConversions(unsigned long long, supported, supported);
QVConversions(float, supported, supported);
QVConversions(double, supported, supported);
QVConversions(QString, supported, supported);
QVConversions(QColor, unsupported, supported);
QVConversions(QFont, supported, supported);
QVConversions(QDateTime, unsupported, supported);
QVConversions(QDate, unsupported, supported);
QVConversions(QSize, unsupported, supported);
QVConversions(QRect, unsupported, supported);
QVConversions(QPoint, unsupported, supported);
QVConversions(QSizeF, unsupported, supported);
QVConversions(QRectF, unsupported, supported);
QVConversions(QPointF, unsupported, supported);
QVConversions(QByteArray, supported, supported);
QVConversions(QStringList, unsupported, supported);
QVConversions(QVariantList, unsupported, supported);
}
}

#endif

