QGIS API Documentation  3.21.0-Master (5b68dc587e)
qgscachedfeatureiterator.h
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1 /***************************************************************************
2  qgscachedfeatureiterator.h
3  --------------------------------------
4  Date : 12.2.2013
5  Copyright : (C) 2013 Matthias Kuhn
6  Email : matthias at opengis dot ch
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 
16 #ifndef QGSCACHEDFEATUREITERATOR_H
17 #define QGSCACHEDFEATUREITERATOR_H
18 
19 #include "qgis_core.h"
20 #include "qgsfeature.h"
21 #include "qgsfeatureiterator.h"
22 #include "qgscoordinatetransform.h"
23 
25 
33 {
34  public:
35 
42  QgsCachedFeatureIterator( QgsVectorLayerCache *vlCache, const QgsFeatureRequest &featureRequest );
43 
45 
51  bool rewind() override;
52 
58  bool close() override;
59 
60  // QgsAbstractFeatureIterator interface
61  protected:
62 
71  bool fetchFeature( QgsFeature &f ) override;
72 
79  bool nextFeatureFilterFids( QgsFeature &f ) override { return fetchFeature( f ); }
80 
81  private:
82 #ifdef SIP_RUN
84 #endif
85 
86  QList< QgsFeatureId > mFeatureIds;
87  QgsVectorLayerCache *mVectorLayerCache = nullptr;
88  QList< QgsFeatureId >::ConstIterator mFeatureIdIterator;
89  QgsCoordinateTransform mTransform;
90  QgsRectangle mFilterRect;
91 
92  QgsGeometry mDistanceWithinGeom;
93  std::unique_ptr< QgsGeometryEngine > mDistanceWithinEngine;
94  double mDistanceWithin = 0;
95 };
96 
104 {
105  public:
106 
113  QgsCachedFeatureWriterIterator( QgsVectorLayerCache *vlCache, const QgsFeatureRequest &featureRequest );
114 
120  bool rewind() override;
121 
127  bool close() override;
128 
129  protected:
130 
139  bool fetchFeature( QgsFeature &f ) override;
140 
141  private:
142  QgsFeatureIterator mFeatIt;
143  QgsVectorLayerCache *mVectorLayerCache = nullptr;
144  QgsFeatureIds mFids;
145  QgsCoordinateTransform mTransform;
146  QgsRectangle mFilterRect;
147 
148 };
149 #endif // QGSCACHEDFEATUREITERATOR_H
Internal feature iterator to be implemented within data providers.
virtual bool rewind()=0
reset the iterator to the starting position
virtual bool fetchFeature(QgsFeature &f)=0
If you write a feature iterator for your provider, this is the method you need to implement!...
virtual bool close()=0
end of iterating: free the resources / lock
Delivers features from the cache.
~QgsCachedFeatureIterator() override
bool nextFeatureFilterFids(QgsFeature &f) override
We have a local special iterator for FilterFids, no need to run the generic.
Uses another iterator as backend and writes features to the cache.
Class for doing transforms between two map coordinate systems.
Wrapper for iterator of features from vector data provider or vector layer.
This class wraps a request for features to a vector layer (or directly its vector data provider).
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:124
A rectangle specified with double values.
Definition: qgsrectangle.h:42
This class caches features of a given QgsVectorLayer.
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeatureid.h:37