QGIS API Documentation  2.17.0-Master (06698cd)
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 
38 {
39  public:
42 
43  virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest& request ) override;
44 
46 
47  protected:
48 
50 
52 
54 
56 
58 
59  // A deep-copy is only performed, if the original maps change
60  // see here https://github.com/qgis/Quantum-GIS/pull/673
61  // for explanation
68 
69  long mCrsId;
70 };
71 
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  virtual bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
96 
98  virtual bool prepareSimplification( const QgsSimplifyMethod& simplifyMethod ) override;
99 
101  void rewindEditBuffer();
102 
104  void prepareJoin( int fieldIdx );
105 
107  void prepareExpression( int fieldIdx );
108 
110  void prepareFields();
111 
113  void prepareField( int fieldIdx );
114 
116  bool fetchNextAddedFeature( QgsFeature& f );
118  bool fetchNextChangedGeomFeature( QgsFeature& f );
120  bool fetchNextChangedAttributeFeature( QgsFeature& f );
122  void useAddedFeature( const QgsFeature& src, QgsFeature& f );
124  void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry& geom, QgsFeature& f );
126  bool nextFeatureFid( QgsFeature& f );
128  void addJoinedAttributes( QgsFeature &f );
129 
139  void addVirtualAttributes( QgsFeature &f );
140 
147  void addExpressionAttribute( QgsFeature& f, int attrIndex );
148 
152  void updateChangedAttributes( QgsFeature& f );
153 
157  void updateFeatureGeometry( QgsFeature& f );
158 
163  {
169  int joinField;
170 
171  void addJoinedAttributesCached( QgsFeature& f, const QVariant& joinValue ) const;
172  void addJoinedAttributesDirect( QgsFeature& f, const QVariant& joinValue ) const;
173  };
174 
179 
180  // only related to editing
184 
185  bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
186 
190 
192 
194 
195  private:
196  QScopedPointer<QgsExpressionContext> mExpressionContext;
197 
198  QgsInterruptionChecker* mInterruptionChecker;
199 
200  QList< int > mPreparedFields;
201  QList< int > mFieldsToPrepare;
202 
207  bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
208 
210  virtual bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
211 };
212 
213 #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:209
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.
Helper template that cares of two things: 1.