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       1                 :            : /***************************************************************************
       2                 :            :                           qgsvectorlayerjoinbuffer.h
       3                 :            :                           ---------------------------
       4                 :            :     begin                : Feb 09, 2011
       5                 :            :     copyright            : (C) 2011 by Marco Hugentobler
       6                 :            :     email                : marco dot hugentobler at sourcepole dot ch
       7                 :            :  ***************************************************************************/
       8                 :            : 
       9                 :            : /***************************************************************************
      10                 :            :  *                                                                         *
      11                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      12                 :            :  *   it under the terms of the GNU General Public License as published by  *
      13                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      14                 :            :  *   (at your option) any later version.                                   *
      15                 :            :  *                                                                         *
      16                 :            :  ***************************************************************************/
      17                 :            : 
      18                 :            : #ifndef QGSVECTORLAYERJOINBUFFER_H
      19                 :            : #define QGSVECTORLAYERJOINBUFFER_H
      20                 :            : 
      21                 :            : #include "qgis_core.h"
      22                 :            : #include "qgis_sip.h"
      23                 :            : #include "qgsvectorlayerjoininfo.h"
      24                 :            : #include "qgsfeaturesink.h"
      25                 :            : 
      26                 :            : #include <QHash>
      27                 :            : #include <QString>
      28                 :            : 
      29                 :            : 
      30                 :            : typedef QList< QgsVectorLayerJoinInfo > QgsVectorJoinList;
      31                 :            : 
      32                 :            : 
      33                 :            : /**
      34                 :            :  * \ingroup core
      35                 :            :  * \brief Manages joined fields for a vector layer.
      36                 :            : */
      37                 :            : class CORE_EXPORT QgsVectorLayerJoinBuffer : public QObject, public QgsFeatureSink
      38                 :            : {
      39                 :            :     Q_OBJECT
      40                 :            :   public:
      41                 :            :     QgsVectorLayerJoinBuffer( QgsVectorLayer *layer = nullptr );
      42                 :            : 
      43                 :            :     /**
      44                 :            :      * Joins another vector layer to this layer
      45                 :            :      * \param joinInfo join object containing join layer id, target and source field
      46                 :            :      * \returns (since 2.6) whether the join was successfully added
      47                 :            :     */
      48                 :            :     bool addJoin( const QgsVectorLayerJoinInfo &joinInfo );
      49                 :            : 
      50                 :            :     /**
      51                 :            :      * Removes a vector layer join
      52                 :            :      * \returns TRUE if join was found and successfully removed
      53                 :            :     */
      54                 :            :     bool removeJoin( const QString &joinLayerId );
      55                 :            : 
      56                 :            :     /**
      57                 :            :      * Updates field map with joined attributes
      58                 :            :      * \param fields map to append joined attributes
      59                 :            :      */
      60                 :            :     void updateFields( QgsFields &fields );
      61                 :            : 
      62                 :            :     //! Calls cacheJoinLayer() for all vector joins
      63                 :            :     void createJoinCaches();
      64                 :            : 
      65                 :            :     //! Saves mVectorJoins to xml under the layer node
      66                 :            :     void writeXml( QDomNode &layer_node, QDomDocument &document ) const;
      67                 :            : 
      68                 :            :     /**
      69                 :            :      * Reads joins from project file.
      70                 :            :      * Does not resolve layer IDs to layers - call resolveReferences() afterwards
      71                 :            :      */
      72                 :            :     void readXml( const QDomNode &layer_node );
      73                 :            : 
      74                 :            :     /**
      75                 :            :      * Resolves layer IDs of joined layers using given project's available layers
      76                 :            :      * \since QGIS 3.0
      77                 :            :      */
      78                 :            :     void resolveReferences( QgsProject *project );
      79                 :            : 
      80                 :            :     //! Quick way to test if there is any join at all
      81                 :        279 :     bool containsJoins() const { return !mVectorJoins.isEmpty(); }
      82                 :            : 
      83                 :          0 :     const QgsVectorJoinList &vectorJoins() const { return mVectorJoins; }
      84                 :            : 
      85                 :            :     /**
      86                 :            :      * Finds the vector join for a layer field index.
      87                 :            :      * \param index this layers attribute index
      88                 :            :      * \param fields fields of the vector layer (including joined fields)
      89                 :            :      * \param sourceFieldIndex Output: field's index in source layer
      90                 :            :      * \returns the vector layer join info
      91                 :            :      */
      92                 :            :     const QgsVectorLayerJoinInfo *joinForFieldIndex( int index, const QgsFields &fields, int &sourceFieldIndex SIP_OUT ) const;
      93                 :            : 
      94                 :            :     /**
      95                 :            :      * Find out what is the first index of the join within fields. Returns -1 if join is not present
      96                 :            :      * \since QGIS 2.6
      97                 :            :      */
      98                 :            :     int joinedFieldsOffset( const QgsVectorLayerJoinInfo *info, const QgsFields &fields );
      99                 :            : 
     100                 :            :     /**
     101                 :            :      * Returns a vector of indices for use in join based on field names from the layer
     102                 :            :      * \since QGIS 2.6
     103                 :            :      */
     104                 :            :     static QVector<int> joinSubsetIndices( QgsVectorLayer *joinLayer, const QStringList &joinFieldsSubset );
     105                 :            : 
     106                 :            :     /**
     107                 :            :      * Returns joins where the field of a target layer is considered as an id.
     108                 :            :      * \param field the field of a target layer
     109                 :            :      * \returns a list of vector joins
     110                 :            :      * \since QGIS 3.0
     111                 :            :      */
     112                 :            :     QList<const QgsVectorLayerJoinInfo *> joinsWhereFieldIsId( const QgsField &field ) const;
     113                 :            : 
     114                 :            :     /**
     115                 :            :      * Returns the joined feature corresponding to the feature.
     116                 :            :      * \param info the vector join information
     117                 :            :      * \param feature the feature of the target layer
     118                 :            :      * \since QGIS 3.0
     119                 :            :      */
     120                 :            :     QgsFeature joinedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;
     121                 :            : 
     122                 :            :     /**
     123                 :            :      * Returns the targeted feature corresponding to the joined feature.
     124                 :            :      * \param info the vector join information
     125                 :            :      * \param feature the feature of the joined layer
     126                 :            :      * \since QGIS 3.0
     127                 :            :      */
     128                 :            :     QgsFeature targetedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;
     129                 :            : 
     130                 :            :     /**
     131                 :            :      * Returns TRUE if the join information is about auxiliary layer, FALSE otherwise
     132                 :            :      *
     133                 :            :      * \param info The join information
     134                 :            :      *
     135                 :            :      * \returns TRUE if the join information is about auxiliary layer, FALSE otherwise
     136                 :            :      *
     137                 :            :      * \since QGIS 3.0
     138                 :            :      */
     139                 :            :     bool isAuxiliaryJoin( const QgsVectorLayerJoinInfo &info ) const;
     140                 :            : 
     141                 :            :     /**
     142                 :            :      * Create a copy of the join buffer
     143                 :            :      * \since QGIS 2.6
     144                 :            :      */
     145                 :            :     QgsVectorLayerJoinBuffer *clone() const SIP_FACTORY;
     146                 :            : 
     147                 :            :     /**
     148                 :            :      * Adds a list of features in joined layers. Features given in parameter
     149                 :            :      * are those added in target layer. If a corresponding joined feature yet
     150                 :            :      * exists in a joined layer, then this feature is just updated. Note that
     151                 :            :      * if a corresponding joined feature has only empty fields, then it's not
     152                 :            :      * created nor added.
     153                 :            :      *
     154                 :            :      * \param features The list of features added in the target layer
     155                 :            :      * \param flags Unused parameter
     156                 :            :      *
     157                 :            :      * \returns FALSE if an error happened, TRUE otherwise
     158                 :            :      *
     159                 :            :      * \since QGIS 3.0
     160                 :            :      */
     161                 :            :     bool addFeatures( QgsFeatureList &features, QgsFeatureSink::Flags flags = QgsFeatureSink::Flags() ) override;
     162                 :            : 
     163                 :            :     /**
     164                 :            :      * Changes attribute value in joined layers. The feature id given in
     165                 :            :      * parameter is the one added in target layer. If the corresponding joined
     166                 :            :      * feature does not exist in a joined layer, then it's automatically
     167                 :            :      * created if its fields are not empty.
     168                 :            :      *
     169                 :            :      * \param fid The feature id
     170                 :            :      * \param field The field to update
     171                 :            :      * \param newValue The new value of the attribute
     172                 :            :      * \param oldValue The old value of the attribute
     173                 :            :      *
     174                 :            :      * \returns FALSE if an error happened, TRUE otherwise
     175                 :            :      *
     176                 :            :      * \since QGIS 3.0
     177                 :            :      */
     178                 :            :     bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
     179                 :            : 
     180                 :            :     /**
     181                 :            :      * Changes attributes' values in joined layers. The feature id given in
     182                 :            :      * parameter is the one added in target layer. If the corresponding joined
     183                 :            :      * feature does not exist in a joined layer, then it's automatically
     184                 :            :      * created if its fields are not empty.
     185                 :            :      *
     186                 :            :      * \param fid The feature id
     187                 :            :      * \param newValues The new values for attributes
     188                 :            :      * \param oldValues The old values for attributes
     189                 :            :      *
     190                 :            :      * \returns FALSE if an error happened, TRUE otherwise
     191                 :            :      *
     192                 :            :      * \since QGIS 3.0
     193                 :            :      */
     194                 :            :     bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
     195                 :            : 
     196                 :            :     /**
     197                 :            :      * Deletes a feature from joined layers. The feature id given in
     198                 :            :      * parameter is the one coming from the target layer.
     199                 :            :      *
     200                 :            :      * \param fid The feature id from the target layer to delete
     201                 :            :      * \param context The chain of features which will be deleted for feedback and to avoid infinite recursions. Can be NULLPTR.
     202                 :            :      *
     203                 :            :      * \returns FALSE if an error happened, TRUE otherwise
     204                 :            :      *
     205                 :            :      * \since QGIS 3.0
     206                 :            :      */
     207                 :            :     bool deleteFeature( QgsFeatureId fid, QgsVectorLayer::DeleteContext *context = nullptr ) const;
     208                 :            : 
     209                 :            :     /**
     210                 :            :      * Deletes a list of features from joined layers. Feature ids given
     211                 :            :      * in a parameter are those coming from the target layer.
     212                 :            :      *
     213                 :            :      * \param fids Feature ids from the target layer to delete
     214                 :            :      * \param context The chain of features who will be deleted for feedback and to avoid infinite recursions. Can be NULLPTR.
     215                 :            :      *
     216                 :            :      * \returns FALSE if an error happened, TRUE otherwise
     217                 :            :      *
     218                 :            :      * \since QGIS 3.0
     219                 :            :      */
     220                 :            :     bool deleteFeatures( const QgsFeatureIds &fids, QgsVectorLayer::DeleteContext *context = nullptr ) const;
     221                 :            : 
     222                 :            :   signals:
     223                 :            : 
     224                 :            :     /**
     225                 :            :      * Emitted whenever the list of joined fields changes (e.g. added join or joined layer's fields change)
     226                 :            :      * \since QGIS 2.6
     227                 :            :      */
     228                 :            :     void joinedFieldsChanged();
     229                 :            : 
     230                 :            :   private slots:
     231                 :            :     void joinedLayerUpdatedFields();
     232                 :            : 
     233                 :            :     void joinedLayerModified();
     234                 :            : 
     235                 :            :     void joinedLayerWillBeDeleted();
     236                 :            : 
     237                 :            :   private:
     238                 :            :     void connectJoinedLayer( QgsVectorLayer *vl );
     239                 :            : 
     240                 :            :   private:
     241                 :            : 
     242                 :            :     QgsVectorLayer *mLayer = nullptr;
     243                 :            : 
     244                 :            :     //! Joined vector layers
     245                 :            :     QgsVectorJoinList mVectorJoins;
     246                 :            : 
     247                 :            :     //! Caches attributes of join layer in memory if QgsVectorJoinInfo.memoryCache is TRUE (and the cache is not already there)
     248                 :            :     void cacheJoinLayer( QgsVectorLayerJoinInfo &joinInfo );
     249                 :            : 
     250                 :            :     //! Main mutex to protect most data members that can be modified concurrently
     251                 :            :     QMutex mMutex;
     252                 :            : };
     253                 :            : 
     254                 :            : #endif // QGSVECTORLAYERJOINBUFFER_H