qgsvaluerelationfieldformatter.h

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/***************************************************************************
  qgsvaluerelationfieldformatter.h - QgsValueRelationFieldFormatter

 ---------------------
 begin                : 3.12.2016
 copyright            : (C) 2016 by Matthias Kuhn
 email                : [email protected]
 ***************************************************************************
 *                                                                         *
 *   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 QGSVALUERELATIONFIELDKIT_H
#define QGSVALUERELATIONFIELDKIT_H

#include "qgis_core.h"
#include "qgsfieldformatter.h"
#include "qgsexpression.h"
#include "qgsexpressioncontext.h"

#include <QVector>
#include <QVariant>


class CORE_EXPORT QgsValueRelationFieldFormatter : public QgsFieldFormatter
{
  public:
    struct ValueRelationItem
    {
      ValueRelationItem( const QVariant &key, const QString &value )
        : key( key )
        , value( value )
      {}

      ValueRelationItem() = default;

      QVariant key;
      QString value;
    };

    typedef QVector < QgsValueRelationFieldFormatter::ValueRelationItem > ValueRelationCache;

    QgsValueRelationFieldFormatter() = default;

    QString id() const override;
    QString representValue( QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value ) const override;

    QVariant sortValue( QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config, const QVariant &cache, const QVariant &value ) const override;

    QVariant createCache( QgsVectorLayer *layer, int fieldIndex, const QVariantMap &config ) const override;

    static QStringList valueToStringList( const QVariant &value );

    static QgsValueRelationFieldFormatter::ValueRelationCache createCache( const QVariantMap &config, const QgsFeature &formFeature = QgsFeature() );

    static bool expressionRequiresFormScope( const QString &expression );

    static QSet<QString> expressionFormAttributes( const QString &expression );

    static QSet<QString> expressionFormVariables( const QString &expression );

    static bool expressionIsUsable( const QString &expression, const QgsFeature &feature );

};

Q_DECLARE_METATYPE( QgsValueRelationFieldFormatter::ValueRelationCache )

#endif // QGSVALUERELATIONFIELDKIT_H