qgsfeaturefiltermodel.h

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/***************************************************************************
  qgsfeaturefiltermodel.h - QgsFeatureFilterModel

 ---------------------
 begin                : 10.3.2017
 copyright            : (C) 2017 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 QGSFEATUREFILTERMODEL_H
#define QGSFEATUREFILTERMODEL_H

#include <QAbstractItemModel>

#include "qgsvectorlayer.h"
#include "qgsconditionalstyle.h"

class QgsFieldExpressionValuesGatherer;

class CORE_EXPORT QgsFeatureFilterModel : public QAbstractItemModel
{
    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 isLoading READ isLoading NOTIFY isLoadingChanged )

    Q_PROPERTY( QString identifierField READ identifierField WRITE setIdentifierField NOTIFY identifierFieldChanged )

    Q_PROPERTY( QVariant extraIdentifierValue READ extraIdentifierValue WRITE setExtraIdentifierValue NOTIFY extraIdentifierValueChanged )

    Q_PROPERTY( int extraIdentifierValueIndex READ extraIdentifierValueIndex NOTIFY extraIdentifierValueIndexChanged )

  public:

    enum Role
    {
      IdentifierValueRole = Qt::UserRole, 
      ValueRole 
    };

    explicit QgsFeatureFilterModel( QObject *parent = nullptr );
    ~QgsFeatureFilterModel() 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;
    QVariant data( const QModelIndex &index, int role ) const override;

    QString filterExpression() const;

    void setFilterExpression( const QString &filterExpression );

    bool isLoading() const;

    QString identifierField() const;

    void setIdentifierField( const QString &identifierField );

    QVariant extraIdentifierValue() const;

    void setExtraIdentifierValue( const QVariant &extraIdentifierValue );

    int extraIdentifierValueIndex() const;

    bool extraValueDoesNotExist() const;

    bool allowNull() const;

    void setAllowNull( bool allowNull );

  signals:

    void sourceLayerChanged();

    void displayExpressionChanged();

    void filterValueChanged();

    void filterExpressionChanged();

    void isLoadingChanged();

    void identifierFieldChanged();

    void filterJobCompleted();

    void extraIdentifierValueChanged();

    void extraIdentifierValueIndexChanged( int index );

    void extraValueDoesNotExistChanged();

    void beginUpdate();

    void endUpdate();

    void allowNullChanged();

  private slots:
    void updateCompleter();
    void gathererThreadFinished();
    void scheduledReload();

  private:
    QSet<QString> requestedAttributes() const;
    void setExtraIdentifierValueIndex( int index );
    void setExtraValueDoesNotExist( bool extraValueDoesNotExist );
    void reload();
    void reloadCurrentFeature();
    void setExtraIdentifierValueUnguarded( const QVariant &extraIdentifierValue );
    struct Entry
    {
      Entry() = default;

      Entry( const QVariant &_identifierValue, const QString &_value, const QgsFeature &_feature )
        : identifierValue( _identifierValue )
        , value( _value )
        , feature( _feature )
      {}

      QVariant identifierValue;
      QString value;
      QgsFeature feature;

      bool operator()( const Entry &lhs, const Entry &rhs ) const;
    };

    QgsConditionalStyle featureStyle( const QgsFeature &feature ) const;

    QgsVectorLayer *mSourceLayer = nullptr;
    QgsExpression mDisplayExpression;
    QString mFilterValue;
    QString mFilterExpression;

    mutable QgsExpressionContext mExpressionContext;
    mutable QMap< QgsFeatureId, QgsConditionalStyle > mEntryStylesMap;
    QVector<Entry> mEntries;
    QgsFieldExpressionValuesGatherer *mGatherer = nullptr;
    QTimer mReloadTimer;
    bool mShouldReloadCurrentFeature = false;
    bool mExtraValueDoesNotExist = false;
    bool mAllowNull = false;

    QString mIdentifierField;

    QVariant mExtraIdentifierValue;

    int mExtraIdentifierValueIndex = -1;

    friend class QgsFieldExpressionValuesGatherer;
};

#endif // QGSFEATUREFILTERMODEL_H