qgsexpressionfieldbuffer.h

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/***************************************************************************
                          qgsexpressionfieldbuffer.h
                          ---------------------------
    begin                : May 27, 2014
    copyright            : (C) 2014 by Matthias Kuhn
    email                : matthias at opengis dot ch
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSEXPRESSIONFIELDBUFFER_H
#define QGSEXPRESSIONFIELDBUFFER_H
 
#include "qgis_core.h"
#include "qgsexpression.h"
#include "qgsfields.h"
 
#include <QDomNode>
#include <QList>
#include <QString>

class CORE_EXPORT QgsExpressionFieldBuffer
{
  public:
    struct ExpressionField
    {
        ExpressionField( const QString &exp, const QgsField &fld )
          : cachedExpression( exp )
          , field( fld )
        {}
 
        QgsExpression cachedExpression;
        QgsField field;
    };
 
    QgsExpressionFieldBuffer() = default;

    void addExpression( const QString &exp, const QgsField &fld );

    void removeExpression( int index );

    void renameExpression( int index, const QString &name );

    void updateExpression( int index, const QString &exp );

    void writeXml( QDomNode &layer_node, QDomDocument &document ) const;

    void readXml( const QDomNode &layer_node );

    void updateFields( QgsFields &flds ) const;
 
    QList<QgsExpressionFieldBuffer::ExpressionField> expressions() const { return mExpressions; }
 
  private:
    QList<ExpressionField> mExpressions;
};
 
#endif // QGSEXPRESSIONFIELDBUFFER_H