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// This file is part of Kig, a KDE program for Interactive Geometry...
// Copyright (C) 2002 Dominique Devriese <devriese@kde.org>
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 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 General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301, USA.
#ifndef FILTER_H
#define FILTER_H
#include <qstring.h>
#include <vector>
class KigFilter;
class ScreenInfo;
class KigDocument;
/**
* This singleton class handles all the input filters.
*/
class KigFilters
{
public:
static KigFilters* instance();
KigFilter* find (const QString& mime);
// bool save ( const KigDocument& data, QTextStream& stream );
/**
* saving is always done with the native filter. We don't support
* output filters..
*/
bool save ( const KigDocument& data, const QString& outfile );
protected:
KigFilters();
static KigFilters* sThis;
typedef std::vector<KigFilter*> vect;
vect mFilters;
};
// KigFilter::load functions should use this macro to conveniently
// return a very useful parse error in a filter's load function..
#define KIG_FILTER_PARSE_ERROR \
{ \
QString locs = i18n( "An error was encountered at " \
"line %1 in file %2." ) \
.arg( __LINE__ ).arg( __FILE__ ); \
parseError( file, locs ); \
return 0; \
}
/**
* This is the base class for an input filter.
*
* All the needed work to add a new input filter to Kig is
* subclassing this class and implement supportMime() and load().
*/
class KigFilter
{
protected:
// shows errors to the user..
void fileNotFound( const QString& file ) const;
void parseError( const QString& file, const QString& explanation = QString::null ) const;
void notSupported( const QString& file, const QString& explanation ) const;
void warning( const QString& explanation ) const;
public:
KigFilter();
virtual ~KigFilter();
/**
* can the filter handle the mimetype \p mime ?
*/
virtual bool supportMime ( const QString& mime );
/**
* load file \p fromfile and build a KigDocument from it.. If this
* function returns 0, that means that an error occurred while
* loading ( implementations of this function are responsible for
* showing an error message themselves, using the above error
* functions ). If this functions returns non-0, the caller owns
* the returned KigDocument ( that was allocated with "new" ).
*/
virtual KigDocument* load ( const QString& fromfile ) = 0;
};
#endif
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