qgsfeaturepickermodelbase.h

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/***************************************************************************
  qgsfeaturefiltermodel.h - QgsFeatureFilterModel
 ---------------------
 begin                : 10.3.2017
 copyright            : (C) 2017 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 QGSFEATUREFILTERMODELBASE_H
#define QGSFEATUREFILTERMODELBASE_H
 
#include "qgsconditionalstyle.h"
#include "qgsfeatureexpressionvaluesgatherer.h"
 
#include <QAbstractItemModel>
#include <QTimer>
 
class CORE_EXPORT QgsFeaturePickerModelBase : public QAbstractItemModel SIP_ABSTRACT
{
    Q_OBJECT
 
    Q_PROPERTY( QgsVectorLayer *sourceLayer READ sourceLayer WRITE setSourceLayer NOTIFY sourceLayerChanged )
    Q_PROPERTY( QString displayExpression READ displayExpression WRITE setDisplayExpression NOTIFY displayExpressionChanged )
    Q_PROPERTY( QString filterValue READ filterValue WRITE setFilterValue NOTIFY filterValueChanged )
    Q_PROPERTY( QString filterExpression READ filterExpression WRITE setFilterExpression NOTIFY filterExpressionChanged )
    Q_PROPERTY( bool allowNull READ allowNull WRITE setAllowNull NOTIFY allowNullChanged )
    Q_PROPERTY( bool fetchGeometry READ fetchGeometry WRITE setFetchGeometry NOTIFY fetchGeometryChanged )
    Q_PROPERTY( int fetchLimit READ fetchLimit WRITE setFetchLimit NOTIFY fetchLimitChanged )
    Q_PROPERTY( int extraIdentifierValueIndex READ extraIdentifierValueIndex NOTIFY extraIdentifierValueIndexChanged )
 
  public:
 
    enum Role
    {
      IdentifierValueRole = Qt::UserRole, 
      IdentifierValuesRole, 
      ValueRole, 
      FeatureRole, 
      FeatureIdRole 
    };
 
    explicit QgsFeaturePickerModelBase( QObject *parent = nullptr );
    ~QgsFeaturePickerModelBase() override;
 
    QgsVectorLayer *sourceLayer() const;
 
    void setSourceLayer( QgsVectorLayer *sourceLayer );
 
    QString displayExpression() const;
 
    void setDisplayExpression( const QString &displayExpression );
 
    QString filterValue() const;
 
    void setFilterValue( const QString &filterValue );
 
    QModelIndex index( int row, int column, const QModelIndex &parent ) const override;
    QModelIndex parent( const QModelIndex &child ) const override;
    int rowCount( const QModelIndex &parent ) const override;
    int columnCount( const QModelIndex &parent ) const override
    {
      Q_UNUSED( parent )
      return 1;
    }
    QVariant data( const QModelIndex &index, int role ) const override;
 
    QString filterExpression() const;
 
    void setFilterExpression( const QString &filterExpression );
 
    bool isLoading() const;
 
    virtual void setExtraIdentifierValueToNull() = 0;
 
    int extraIdentifierValueIndex() const;
 
    bool extraValueDoesNotExist() const;
 
    bool allowNull() const;
 
    void setAllowNull( bool allowNull );
 
    bool fetchGeometry() const;
 
    void setFetchGeometry( bool fetchGeometry );
 
    int fetchLimit() const;
 
    void setFetchLimit( int fetchLimit );
 
  signals:
 
    void sourceLayerChanged();
 
    void displayExpressionChanged();
 
    void filterValueChanged();
 
    void filterExpressionChanged();
 
    void isLoadingChanged();
 
    void filterJobCompleted();
 
    void extraIdentifierValueChanged();
 
    void extraIdentifierValueIndexChanged( int index );
 
    void extraValueDoesNotExistChanged();
 
    void beginUpdate();
 
    void endUpdate();
 
    void allowNullChanged();
 
    void fetchGeometryChanged();
 
    void fetchLimitChanged();
 
 
  private slots:
    void updateCompleter();
    void scheduledReload();
 
  protected:
 
    QVariant extraIdentifierValue() const;
 
    void setExtraIdentifierValue( const QVariant &extraIdentifierValue );
 
    virtual void requestToReloadCurrentFeature( QgsFeatureRequest &request ) = 0;
 
    void setExtraIdentifierValueUnguarded( const QVariant &identifierValue );
 
#ifndef SIP_RUN
 
    virtual QSet<QString> requestedAttributes() const {return {};}
 
    virtual QgsFeatureExpressionValuesGatherer *createValuesGatherer( const QgsFeatureRequest &request ) const = 0;
 
    virtual QgsFeatureExpressionValuesGatherer::Entry createEntry( const QVariant &identifier ) const = 0;
 
    virtual QVariant entryIdentifier( const QgsFeatureExpressionValuesGatherer::Entry &entry ) const = 0;
 
    virtual bool compareEntries( const QgsFeatureExpressionValuesGatherer::Entry &a, const QgsFeatureExpressionValuesGatherer::Entry &b ) const = 0;
 
    virtual QVariant nullIdentifier() const = 0;
 
    virtual bool identifierIsNull( const QVariant &identifier ) const = 0;
 
    QVector<QgsFeatureExpressionValuesGatherer::Entry> mEntries;
#endif
 
    QVariant mExtraIdentifierValue;
 
    int mExtraValueIndex = -1;
 
  private:
    void setExtraIdentifierValueIndex( int index, bool force = false );
    void setExtraValueDoesNotExist( bool extraValueDoesNotExist );
    void reload();
    void reloadCurrentFeature();
    QSet<QString> requestedAttributesForStyle() const;
 
    QgsConditionalStyle featureStyle( const QgsFeature &feature ) const;
 
    QgsVectorLayer *mSourceLayer = nullptr;
    QgsExpression mDisplayExpression;
    QString mFilterValue;
    QString mFilterExpression;
 
    mutable QgsExpressionContext mExpressionContext;
    mutable QMap< QgsFeatureId, QgsConditionalStyle > mEntryStylesMap;
 
    QgsFeatureExpressionValuesGatherer *mGatherer = nullptr;
    bool mFetchGeometry = true;
    int mFetchLimit = 100;
 
    QTimer mReloadTimer;
    bool mShouldReloadCurrentFeature = false;
    bool mKeepCurrentEntry = false; // need to keep the current value after a reload or if the value does not exist
    bool mExtraValueDoesNotExist = false;
    bool mAllowNull = false;
    bool mIsSettingExtraIdentifierValue = false;
 
    friend class TestQgsFeatureListComboBox;
};
 
#endif // QGSFEATUREFILTERMODELBASE_H