QGIS/src/core/qgsvectorlayerjoinbuffer.h
2018-01-29 07:17:32 +00:00

247 lines
8.5 KiB
C++

/***************************************************************************
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.h"
#include "qgsvectorlayerjoininfo.h"
#include <QHash>
#include <QString>
typedef QList< QgsVectorLayerJoinInfo > QgsVectorJoinList;
/**
* \ingroup core
* Manages joined fields for a vector layer*/
class CORE_EXPORT QgsVectorLayerJoinBuffer : public QObject, public QgsFeatureSink
{
Q_OBJECT
public:
QgsVectorLayerJoinBuffer( QgsVectorLayer *layer = nullptr );
/**
* Joins another vector layer to this layer
\param joinInfo join object containing join layer id, target and source field
\returns (since 2.6) whether the join was successfully added */
bool addJoin( const QgsVectorLayerJoinInfo &joinInfo );
/**
* Removes a vector layer join
\returns true if join was found and successfully removed */
bool removeJoin( const QString &joinLayerId );
/**
* Updates field map with joined attributes
\param fields map to append joined attributes
*/
void updateFields( QgsFields &fields );
//! Calls cacheJoinLayer() for all vector joins
void createJoinCaches();
//! Saves mVectorJoins to xml under the layer node
void writeXml( QDomNode &layer_node, QDomDocument &document ) const;
/**
* Reads joins from project file.
* Does not resolve layer IDs to layers - call resolveReferences() afterwards
*/
void readXml( const QDomNode &layer_node );
/**
* Resolves layer IDs of joined layers using given project's available layers
* \since QGIS 3.0
*/
void resolveReferences( QgsProject *project );
//! Quick way to test if there is any join at all
bool containsJoins() const { return !mVectorJoins.isEmpty(); }
const QgsVectorJoinList &vectorJoins() const { return mVectorJoins; }
/**
* Finds the vector join for a layer field index.
\param index this layers attribute index
\param fields fields of the vector layer (including joined fields)
\param sourceFieldIndex Output: field's index in source layer */
const QgsVectorLayerJoinInfo *joinForFieldIndex( int index, const QgsFields &fields, int &sourceFieldIndex SIP_OUT ) const;
/**
* Find out what is the first index of the join within fields. Returns -1 if join is not present
* \since QGIS 2.6
*/
int joinedFieldsOffset( const QgsVectorLayerJoinInfo *info, const QgsFields &fields );
/**
* Return a vector of indices for use in join based on field names from the layer
* \since QGIS 2.6
*/
static QVector<int> joinSubsetIndices( QgsVectorLayer *joinLayer, const QStringList &joinFieldsSubset );
/**
* Returns joins where the field of a target layer is considered as an id.
* \param field the field of a target layer
* \returns a list of vector joins
* \since QGIS 3.0
*/
QList<const QgsVectorLayerJoinInfo *> joinsWhereFieldIsId( const QgsField &field ) const;
/**
* Returns the joined feature corresponding to the feature.
* \param info the vector join information
* \param feature the feature of the target layer
* \since QGIS 3.0
*/
QgsFeature joinedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;
/**
* Returns the targeted feature corresponding to the joined feature.
* \param info the vector join information
* \param feature the feature of the joined layer
* \since QGIS 3.0
*/
QgsFeature targetedFeatureOf( const QgsVectorLayerJoinInfo *info, const QgsFeature &feature ) const;
/**
* Returns true if the join information is about auxiliary layer, false otherwise
*
* \param info The join information
*
* \returns true if the join information is about auxiliary layer, false otherwise
*
* \since QGIS 3.0
*/
bool isAuxiliaryJoin( const QgsVectorLayerJoinInfo &info ) const;
/**
* Create a copy of the join buffer
* \since QGIS 2.6
*/
QgsVectorLayerJoinBuffer *clone() const SIP_FACTORY;
/**
* Adds a list of features in joined layers. Features given in parameter
* are those added in target layer. If a corresponding joined feature yet
* exists in a joined layer, then this feature is just updated. Note that
* if a corresponding joined feature has only empty fields, then it's not
* created nor added.
*
* \param features The list of features added in the target layer
* \param flags Unused parameter
*
* \returns false if an error happened, true otherwise
*
* \since QGIS 3.0
*/
bool addFeatures( QgsFeatureList &features, QgsFeatureSink::Flags flags = nullptr ) override;
/**
* Changes attribute value in joined layers. The feature id given in
* parameter is the one added in target layer. If the corresponding joined
* feature does not exist in a joined layer, then it's automatically
* created if its fields are not empty.
*
* \param fid The feature id
* \param field The field to update
* \param newValue The new value of the attribute
* \param oldValue The old value of the attribute
*
* \returns false if an error happened, true otherwise
*
* \since QGIS 3.0
*/
bool changeAttributeValue( QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue = QVariant() );
/**
* Changes attributes' values in joined layers. The feature id given in
* parameter is the one added in target layer. If the corresponding joined
* feature does not exist in a joined layer, then it's automatically
* created if its fields are not empty.
*
* \param fid The feature id
* \param newValues The new values for attributes
* \param oldValues The old values for attributes
*
* \returns false if an error happened, true otherwise
*
* \since QGIS 3.0
*/
bool changeAttributeValues( QgsFeatureId fid, const QgsAttributeMap &newValues, const QgsAttributeMap &oldValues = QgsAttributeMap() );
/**
* Deletes a feature from joined layers. The feature id given in
* parameter is the one coming from the target layer.
*
* \param fid The feature id from the target layer to delete
*
* \returns false if an error happened, true otherwise
*
* \since QGIS 3.0
*/
bool deleteFeature( QgsFeatureId fid ) const;
/**
* Deletes a list of features from joined layers. Feature ids given
* in aprameter are those coming from the target layer.
*
* \param fids Feature ids from the target layer to delete
*
* \returns false if an error happened, true otherwise
*
* \since QGIS 3.0
*/
bool deleteFeatures( const QgsFeatureIds &fids ) const;
signals:
/**
* Emitted whenever the list of joined fields changes (e.g. added join or joined layer's fields change)
* \since QGIS 2.6
*/
void joinedFieldsChanged();
private slots:
void joinedLayerUpdatedFields();
void joinedLayerModified();
void joinedLayerWillBeDeleted();
private:
void connectJoinedLayer( QgsVectorLayer *vl );
private:
QgsVectorLayer *mLayer = nullptr;
//! Joined vector layers
QgsVectorJoinList mVectorJoins;
//! Caches attributes of join layer in memory if QgsVectorJoinInfo.memoryCache is true (and the cache is not already there)
void cacheJoinLayer( QgsVectorLayerJoinInfo &joinInfo );
//! Main mutex to protect most data members that can be modified concurrently
QMutex mMutex;
};
#endif // QGSVECTORLAYERJOINBUFFER_H