src/core/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 "qgsfeature.h"
#include "qgsvectorlayer.h"

#include <QHash>
#include <QString>

class CORE_EXPORT QgsVectorLayerJoinBuffer
{
  public:
    QgsVectorLayerJoinBuffer();
    ~QgsVectorLayerJoinBuffer();

    void addJoin( QgsVectorJoinInfo joinInfo );

    void removeJoin( const QString& joinLayerId );

    void select( const QgsAttributeList& fetchAttributes,
                 QgsAttributeList& sourceJoinFields, int maxProviderIndex );

    void updateFieldMap( QgsFieldMap& fields, int& maxIndex );

    void updateFeatureAttributes( QgsFeature &f, int maxProviderIndex, bool all = false );

    void createJoinCaches();

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

    void readXml( const QDomNode& layer_node );

    bool containsJoins() const { return ( mVectorJoins.size() > 0 ); }
    bool containsFetchJoins() const { return ( mFetchJoinInfos.size() > 0 ); }

    const QList< QgsVectorJoinInfo >& vectorJoins() const { return mVectorJoins; }

    const QgsVectorJoinInfo* joinForFieldIndex( int index, int maxProviderIndex, int& indexOffset ) const;

    static bool maximumIndex( const QgsFieldMap& fMap, int& index );

  private:

    QList< QgsVectorJoinInfo > mVectorJoins;

    QMap<QgsVectorLayer*, QgsFetchJoinInfo> mFetchJoinInfos;

    void cacheJoinLayer( QgsVectorJoinInfo& joinInfo );

    void addJoinedFeatureAttributes( QgsFeature& f, const QgsVectorJoinInfo& joinInfo, const QString& joinFieldName, const QVariant& joinValue,
                                     const QgsAttributeList& attributes, int attributeIndexOffset );
};

#endif // QGSVECTORLAYERJOINBUFFER_H

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