qgsvectorlayerjoinbuffer.h

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/***************************************************************************
                          qgsvectorlayerjoinbuffer.h
                          ---------------------------
    begin                : Feb 09, 2011
    copyright            : (C) 2011 by Marco Hugentobler
    email                : marco dot hugentobler at sourcepole 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 QGSVECTORLAYERJOINBUFFER_H
#define QGSVECTORLAYERJOINBUFFER_H
 
#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgsfeaturesink.h"
#include "qgsvectorlayerjoininfo.h"
 
#include <QHash>
#include <QString>
 
typedef QList< QgsVectorLayerJoinInfo > QgsVectorJoinList;
 

class CORE_EXPORT QgsVectorLayerJoinBuffer : public QObject, public QgsFeatureSink
{
    Q_OBJECT
  public:
    QgsVectorLayerJoinBuffer( QgsVectorLayer *layer = nullptr );

    bool addJoin( const QgsVectorLayerJoinInfo &joinInfo );

    bool removeJoin( const QString &joinLayerId );

    void updateFields( QgsFields &fields );

    void createJoinCaches();

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

    void readXml( const QDomNode &layer_node );

    void resolveReferences( QgsProject *project );

    bool containsJoins() const { return !mVectorJoins.isEmpty(); }
 
    const QgsVectorJoinList &vectorJoins() const { return mVectorJoins; }

    const QgsVectorLayerJoinInfo *joinForFieldIndex( int index, const QgsFields &fields, int &sourceFieldIndex SIP_OUT ) const;

    int joinedFieldsOffset( const QgsVectorLayerJoinInfo *info, const QgsFields &fields );

    static QVector<int> joinSubsetIndices( QgsVectorLayer *joinLayer, const QStringList &joinFieldsSubset );

    static QVector<int> joinSubsetIndices( const QgsFields &joinLayerFields, const QStringList &joinFieldsSubset );

    QList<const QgsVectorLayerJoinInfo *> joinsWhereFieldIsId( const QgsField &field ) const;

    QgsFeature joinedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;

    QgsFeature targetedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;

    bool isAuxiliaryJoin( const QgsVectorLayerJoinInfo &info ) const;

    QgsVectorLayerJoinBuffer *clone() const SIP_FACTORY;
 
    using QgsFeatureSink::addFeatures;
    bool addFeatures( QgsFeatureList &features, QgsFeatureSink::Flags flags = QgsFeatureSink::Flags() ) override;

    bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );

    bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );

    bool deleteFeature( QgsFeatureId fid, QgsVectorLayer::DeleteContext *context = nullptr ) const;

    bool deleteFeatures( const QgsFeatureIds &fids, QgsVectorLayer::DeleteContext *context = nullptr ) const;
 
  signals:

    void joinedFieldsChanged();
 
  private slots:
    void joinedLayerUpdatedFields();
 
    void joinedLayerModified();
 
    void joinedLayerWillBeDeleted();
 
  private:
    void connectJoinedLayer( QgsVectorLayer *vl );
 
  private:
 
    QgsVectorLayer *mLayer = nullptr;

    QgsVectorJoinList mVectorJoins;

    void cacheJoinLayer( QgsVectorLayerJoinInfo &joinInfo );

    QMutex mMutex;
};
 
#endif // QGSVECTORLAYERJOINBUFFER_H