qgsvaluerelationfieldformatter.h

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/***************************************************************************
  qgsvaluerelationfieldformatter.h - QgsValueRelationFieldFormatter
 
 ---------------------
 begin                : 3.12.2016
 copyright            : (C) 2016 by Matthias Kuhn
 email                : matthias@opengis.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 QGSVALUERELATIONFIELDKIT_H
#define QGSVALUERELATIONFIELDKIT_H
 
#include "qgis_core.h"
#include "qgsexpression.h"
#include "qgsexpressioncontext.h"
#include "qgsfieldformatter.h"
 
#include <QVariant>
#include <QVector>
 
class QgsProject;

class CORE_EXPORT QgsValueRelationFieldFormatter : public QgsFieldFormatter
{
  public:
    struct ValueRelationItem
    {
        ValueRelationItem( const QVariant &key, const QString &value, const QString &description = QString(), const QVariant group = QVariant() )
          : key( key )
          , value( value )
          , description( description )
          , group( group )
        {}
 
        ValueRelationItem() = default;
 
        QVariant key;
        QString value;
        QString description;
        QVariant group;
    };
 
    typedef QVector< QgsValueRelationFieldFormatter::ValueRelationItem > ValueRelationCache;

    QgsValueRelationFieldFormatter();
 
    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 );
 
    // TODO QGIS 5.0 -- remove this version of function in favor of the one with explicit project parameter
    Q_DECL_DEPRECATED static QgsValueRelationFieldFormatter::ValueRelationCache createCache(
      const QVariantMap &config, const QgsFeature &formFeature = QgsFeature(), const QgsFeature &parentFormFeature = QgsFeature()
    ) SIP_DEPRECATED;

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

    static bool expressionRequiresFormScope( const QString &expression );

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

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

    static bool expressionRequiresParentFormScope( const QString &expression );

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

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

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

    static QgsVectorLayer *resolveLayer( const QVariantMap &config, const QgsProject *project );
 
    QList<QgsVectorLayerRef> layerDependencies( const QVariantMap &config ) const override SIP_SKIP;
 
    QVariantList availableValues( const QVariantMap &config, int countLimit, const QgsFieldFormatterContext &context ) const override;
};
 
Q_DECLARE_METATYPE( QgsValueRelationFieldFormatter::ValueRelationCache )
 
#endif // QGSVALUERELATIONFIELDKIT_H