QGIS API Documentation
qgsvectorlayerfeatureiterator.h
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1 /***************************************************************************
2  qgsvectorlayerfeatureiterator.h
3  ---------------------
4  begin : Dezember 2012
5  copyright : (C) 2012 by Martin Dobias
6  email : wonder dot sk at gmail dot com
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 #ifndef QGSVECTORLAYERFEATUREITERATOR_H
16 #define QGSVECTORLAYERFEATUREITERATOR_H
17 
18 #include "qgsfeatureiterator.h"
19 
20 #include <QSet>
21 
23 
25 class QgsVectorLayer;
28 struct QgsVectorJoinInfo;
30 
32 
37 {
38  public:
41 
42  virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest& request ) override;
43 
45 
46  protected:
47 
49 
51 
53 
55 
57 
59 
60  // A deep-copy is only performed, if the original maps change
61  // see here https://github.com/qgis/Quantum-GIS/pull/673
62  // for explanation
69 
70  long mCrsId;
71 };
72 
73 
74 class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
75 {
76  public:
77  QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource* source, bool ownSource, const QgsFeatureRequest& request );
78 
80 
82  virtual bool rewind() override;
83 
85  virtual bool close() override;
86 
87  virtual void setInterruptionChecker( QgsInterruptionChecker* interruptionChecker ) override;
88 
89  protected:
91  virtual bool fetchFeature( QgsFeature& feature ) override;
92 
95  inline virtual bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
96 
98  virtual bool prepareSimplification( const QgsSimplifyMethod& simplifyMethod ) override;
99 
101  void rewindEditBuffer();
103  void prepareJoins();
105  void prepareExpressions();
107  bool fetchNextAddedFeature( QgsFeature& f );
109  bool fetchNextChangedGeomFeature( QgsFeature& f );
111  bool fetchNextChangedAttributeFeature( QgsFeature& f );
113  void useAddedFeature( const QgsFeature& src, QgsFeature& f );
115  void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry& geom, QgsFeature& f );
117  bool nextFeatureFid( QgsFeature& f );
119  void addJoinedAttributes( QgsFeature &f );
120 
130  void addVirtualAttributes( QgsFeature &f );
131 
135  void updateChangedAttributes( QgsFeature& f );
136 
140  void updateFeatureGeometry( QgsFeature& f );
141 
146  {
152  int joinField;
153 
154  void addJoinedAttributesCached( QgsFeature& f, const QVariant& joinValue ) const;
155  void addJoinedAttributesDirect( QgsFeature& f, const QVariant& joinValue ) const;
156  };
157 
162 
163  // only related to editing
167 
168  bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
169 
173 
175 
177 
178  private:
180  QgsAbstractGeometrySimplifier* mEditGeometrySimplifier;
181 
182  QScopedPointer<QgsExpressionContext> mExpressionContext;
183 
184  QgsInterruptionChecker* mInterruptionChecker;
185 
190  bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
191 
193  virtual bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
194 };
195 
196 #endif // QGSVECTORLAYERFEATUREITERATOR_H
QgsAbstractFeatureSource * mProviderFeatureSource
Wrapper for iterator of features from vector data provider or vector layer.
QgsVectorLayerJoinBuffer * mJoinBuffer
QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt
QgsGeometryMap::ConstIterator mFetchChangedGeomIt
QMap< QgsFeatureId, QgsFeature > QgsFeatureMap
Container of fields for a vector layer.
Definition: qgsfield.h:187
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:76
QMap< int, QgsExpression * > mExpressionFieldInfo
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:187
QgsVectorLayer * joinLayer
resolved pointer to the joined layer
QMap< const QgsVectorJoinInfo *, FetchJoinInfo > mFetchJoinInfo
Information about joins used in the current select() statement.
Manages joined fields for a vector layer.
int joinField
index of field (of the joined layer) must have equal value
Interface that can be optionaly attached to an iterator so its nextFeature() implementaton can check ...
const QgsVectorJoinInfo * joinInfo
cannonical source of information about the join
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
This class wraps a request for features to a vector layer (or directly its vector data provider)...
QgsExpressionFieldBuffer * mExpressionFieldBuffer
Base class that can be used for any class that is capable of returning features.
Partial snapshot of vector layer&#39;s state (only the members necessary for access to features) ...
QgsVectorLayerFeatureSource(QgsVectorLayer *layer)
int indexOffset
at what position the joined fields start
int targetField
index of field (of this layer) that drives the join
Buffers information about expression fields for a vector layer.
virtual QgsFeatureIterator getFeatures(const QgsFeatureRequest &request) override
Get an iterator for features matching the specified request.
Join information prepared for fast attribute id mapping in QgsVectorLayerJoinBuffer::updateFeatureAtt...
qint64 QgsFeatureId
Definition: qgsfeature.h:31
This class contains information about how to simplify geometries fetched from a QgsFeatureIterator.
virtual bool nextFeatureFilterExpression(QgsFeature &f) override
Overrides default method as we only need to filter features in the edit buffer while for others filte...
QgsChangedAttributesMap mChangedAttributeValues
Represents a vector layer which manages a vector based data sets.
Abstract base class for simplify geometries using a specific algorithm.
Helper template that cares of two things: 1.