qgsrelationmanager.h

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/***************************************************************************
    qgsrelationmanager.h
     --------------------------------------
    Date                 : 1.3.2013
    Copyright            : (C) 2013 Matthias Kuhn
    Email                : matthias at opengis 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 QGSRELATIONMANAGER_H
#define QGSRELATIONMANAGER_H

#include "qgis_core.h"
#include <QObject>
#include <QPair>
#include <QDomNode>
#include <QDomDocument>

#include "qgsrelation.h"

class QgsProject;
class QgsVectorLayer;

class CORE_EXPORT QgsRelationManager : public QObject
{
    Q_OBJECT

  public:

    explicit QgsRelationManager( QgsProject *project = nullptr );

    void setRelations( const QList<QgsRelation> &relations );

    QMap<QString, QgsRelation> relations() const;

    void addRelation( const QgsRelation &relation );

    void removeRelation( const QString &id );

    void removeRelation( const QgsRelation &relation );

    Q_INVOKABLE QgsRelation relation( const QString &id ) const;

    QList<QgsRelation> relationsByName( const QString &name ) const;

    void clear();

    QList<QgsRelation> referencingRelations( const QgsVectorLayer *layer = nullptr, int fieldIdx = -2 ) const;

    QList<QgsRelation> referencedRelations( QgsVectorLayer *layer = nullptr ) const;

    static QList<QgsRelation> discoverRelations( const QList<QgsRelation> &existingRelations, const QList<QgsVectorLayer *> &layers );

  signals:
    void relationsLoaded();

    void changed();

  private slots:
    void readProject( const QDomDocument &doc, QgsReadWriteContext &context );
    void writeProject( QDomDocument &doc );
    void layersRemoved( const QStringList &layers );

  private:
    QMap<QString, QgsRelation> mRelations;

    QgsProject *mProject = nullptr;
};

#endif // QGSRELATIONMANAGER_H