qgsvectorlayerfeatureiterator.h

Go to the documentation of this file.

/***************************************************************************
    qgsvectorlayerfeatureiterator.h
    ---------------------
    begin                : Dezember 2012
    copyright            : (C) 2012 by Martin Dobias
    email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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 QGSVECTORLAYERFEATUREITERATOR_H
#define QGSVECTORLAYERFEATUREITERATOR_H
 
#include <memory>
 
#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgscoordinatereferencesystem.h"
#include "qgscoordinatetransform.h"
#include "qgsexpressioncontextscopegenerator.h"
#include "qgsfeatureiterator.h"
#include "qgsfeaturesource.h"
#include "qgsfields.h"
 
#include <QPointer>
#include <QSet>
 
typedef QMap<QgsFeatureId, QgsFeature> QgsFeatureMap SIP_SKIP;
 
class QgsExpressionFieldBuffer;
class QgsVectorLayer;
class QgsVectorLayerEditBuffer;
class QgsVectorLayerJoinBuffer;
class QgsVectorLayerJoinInfo;
class QgsExpressionContext;
 
class QgsVectorLayerFeatureIterator;
 
#ifdef SIP_RUN
% ModuleHeaderCode
#include "qgsfeatureiterator.h"
% End
#endif

class CORE_EXPORT QgsVectorLayerFeatureSource : public QgsAbstractFeatureSource
{
  public:

    explicit QgsVectorLayerFeatureSource( const QgsVectorLayer *layer );
 
    QgsVectorLayerFeatureSource( const QgsVectorLayerFeatureSource &other ) = delete;
    QgsVectorLayerFeatureSource &operator==( const QgsVectorLayerFeatureSource &other ) = delete;
 
    ~QgsVectorLayerFeatureSource() override;
 
    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) override;
 
    friend class QgsVectorLayerFeatureIterator SIP_SKIP;

    QgsFields fields() const;

    QgsCoordinateReferenceSystem crs() const;

    QString id() const;
 
  protected:
 
    std::unique_ptr< QgsAbstractFeatureSource > mProviderFeatureSource;
 
    std::unique_ptr< QgsVectorLayerJoinBuffer > mJoinBuffer;
 
#ifndef SIP_RUN

    struct JoinLayerSource
    {

      std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;

      QgsFields joinLayerFields;
    };

    QMap< QString, JoinLayerSource > mJoinSources;
#endif
 
    std::unique_ptr< QgsExpressionFieldBuffer > mExpressionFieldBuffer;
 
    QgsFields mFields;
 
    QString mId;
 
    QgsExpressionContextScope mLayerScope;
 
    bool mHasEditBuffer;
 
    // A deep-copy is only performed, if the original maps change
    // see here https://github.com/qgis/Quantum-GIS/pull/673
    // for explanation
    QgsFeatureMap mAddedFeatures;
    QgsGeometryMap mChangedGeometries;
    QgsFeatureIds mDeletedFeatureIds;
    QList<QgsField> mAddedAttributes;
    QgsChangedAttributesMap mChangedAttributeValues;
    QgsAttributeList mDeletedAttributeIds;
 
    QgsCoordinateReferenceSystem mCrs;
 
  private:
#ifdef SIP_RUN
    QgsVectorLayerFeatureSource( const QgsVectorLayerFeatureSource &other );
#endif
};

class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
{
  public:
    QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource *source, bool ownSource, const QgsFeatureRequest &request );
 
    ~QgsVectorLayerFeatureIterator() override;

    bool rewind() override;

    bool close() override;
 
    void setInterruptionChecker( QgsFeedback *interruptionChecker ) override SIP_SKIP;

    struct CORE_EXPORT FetchJoinInfo
    {
      const QgsVectorLayerJoinInfo *joinInfo;
      QgsAttributeList attributes;
      QMap<int, int> attributesSourceToDestLayerMap SIP_SKIP;
      int indexOffset;
 
#ifndef SIP_RUN

      std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;

      QgsFields joinLayerFields;
#endif

      int targetField;

      int joinField;
 
      void addJoinedAttributesCached( QgsFeature &f, const QVariant &joinValue ) const;
      void addJoinedAttributesDirect( QgsFeature &f, const QVariant &joinValue ) const;
    };
 
    bool isValid() const override;
 
  protected:
    bool fetchFeature( QgsFeature &feature ) override;

    bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }

    bool prepareSimplification( const QgsSimplifyMethod &simplifyMethod ) override;

    void rewindEditBuffer() SIP_SKIP;

    void prepareJoin( int fieldIdx ) SIP_SKIP;

    void prepareExpression( int fieldIdx ) SIP_SKIP;

    void prepareFields() SIP_SKIP;

    void prepareField( int fieldIdx ) SIP_SKIP;

    bool fetchNextAddedFeature( QgsFeature &f ) SIP_SKIP;
    bool fetchNextChangedGeomFeature( QgsFeature &f ) SIP_SKIP;
    bool fetchNextChangedAttributeFeature( QgsFeature &f ) SIP_SKIP;
    void useAddedFeature( const QgsFeature &src, QgsFeature &f ) SIP_SKIP;
    void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry &geom, QgsFeature &f ) SIP_SKIP;
    bool nextFeatureFid( QgsFeature &f ) SIP_SKIP;
    void addJoinedAttributes( QgsFeature &f ) SIP_SKIP;

    void addVirtualAttributes( QgsFeature &f ) SIP_SKIP;

    void addExpressionAttribute( QgsFeature &f, int attrIndex ) SIP_SKIP;

    void updateChangedAttributes( QgsFeature &f ) SIP_SKIP;

    void updateFeatureGeometry( QgsFeature &f ) SIP_SKIP;
 
    QgsFeatureRequest mProviderRequest;
    QgsFeatureIterator mProviderIterator;
    QgsFeatureRequest mChangedFeaturesRequest;
    QgsFeatureIterator mChangedFeaturesIterator;
 
    // filter bounding box constraint, in SOURCE CRS
    QgsRectangle mFilterRect;
    bool mHasValidTransform = false;
    QgsCoordinateTransform mTransform;
 
    // distance within constraint reference geometry and distance IN DESTINATION CRS
    QgsGeometry mDistanceWithinGeom;
    std::shared_ptr< QgsGeometryEngine > mDistanceWithinEngine;
    double mDistanceWithin = 0;
 
    // only related to editing
    QSet<QgsFeatureId> mFetchConsidered;
    QgsGeometryMap::ConstIterator mFetchChangedGeomIt;
    QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt;
 
    bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not

    QMap<const QgsVectorLayerJoinInfo *, QgsVectorLayerFeatureIterator::FetchJoinInfo> mFetchJoinInfo;
 
    QMap<int, QgsExpression *> mExpressionFieldInfo;
 
    bool mHasVirtualAttributes;
 
  private:
#ifdef SIP_RUN
    QgsVectorLayerFeatureIterator( const QgsVectorLayerFeatureIterator &rhs );
#endif
 
    void createExpressionContext();
    std::unique_ptr<QgsExpressionContext> mExpressionContext;
 
    QgsFeedback *mInterruptionChecker = nullptr;
 
    QList< int > mPreparedFields;
    QList< int > mFieldsToPrepare;

    QList< FetchJoinInfo > mOrderedJoinInfoList;

    bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;

    bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
 
    void createOrderedJoinList();

    bool postProcessFeature( QgsFeature &feature );

    bool checkGeometryValidity( const QgsFeature &feature );
 
    bool mDelegatedOrderByToProvider = false;
};
 
 

class CORE_EXPORT QgsVectorLayerSelectedFeatureSource : public QgsFeatureSource, public QgsExpressionContextScopeGenerator
{
  public:

    QgsVectorLayerSelectedFeatureSource( QgsVectorLayer *layer );
 
    QgsVectorLayerSelectedFeatureSource( const QgsVectorLayerSelectedFeatureSource &other ) = delete;
    QgsVectorLayerSelectedFeatureSource &operator==( const QgsVectorLayerSelectedFeatureSource &other ) = delete;
 
    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
    QgsCoordinateReferenceSystem sourceCrs() const override;
    QgsFields fields() const override;
    Qgis::WkbType wkbType() const override;
    long long featureCount() const override;
    QString sourceName() const override;
    QgsExpressionContextScope *createExpressionContextScope() const override;
    Qgis::SpatialIndexPresence hasSpatialIndex() const override;
 
  private:
 
#ifdef SIP_RUN
    QgsVectorLayerSelectedFeatureSource( const QgsVectorLayerSelectedFeatureSource &other );
#endif
 
    // ideally this wouldn't be mutable, but QgsVectorLayerFeatureSource has non-const getFeatures()
    mutable QgsVectorLayerFeatureSource mSource;
    QgsFeatureIds mSelectedFeatureIds;
    Qgis::WkbType mWkbType = Qgis::WkbType::Unknown;
    QString mName;
    QPointer< QgsVectorLayer > mLayer;
 
};

 
#ifndef SIP_RUN
class QgsVectorLayerSelectedFeatureIterator : public QgsAbstractFeatureIterator
{
  public:
 
    QgsVectorLayerSelectedFeatureIterator( const QgsFeatureIds &selectedFeatureIds,
                                           const QgsFeatureRequest &request,
                                           QgsVectorLayerFeatureSource &source );
 
    bool rewind() override;
    bool close() override;
 
  protected:
    bool fetchFeature( QgsFeature &f ) override;
 
  private:
    QgsFeatureIds mSelectedFeatureIds;
    QgsFeatureIterator mIterator;
 
};
 
#endif

 
#endif // QGSVECTORLAYERFEATUREITERATOR_H