QGIS API Documentation  2.99.0-Master (ae4d26a)
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 "qgis_core.h"
19 #include "qgis_sip.h"
20 #include "qgsfeatureiterator.h"
21 #include "qgsfields.h"
23 #include "qgsfeaturesource.h"
24 
25 #include <QSet>
26 #include <memory>
27 
28 typedef QMap<QgsFeatureId, QgsFeature> QgsFeatureMap SIP_SKIP;
29 
31 class QgsVectorLayer;
36 
38 
39 #ifdef SIP_RUN
40 % ModuleHeaderCode
41 #include "qgsfeatureiterator.h"
42 % End
43 #endif
44 
50 {
51  public:
52 
57  explicit QgsVectorLayerFeatureSource( const QgsVectorLayer *layer );
58 
60 
61  virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) override;
62 
64 
71  QgsFields fields() const;
72 
77  QgsCoordinateReferenceSystem crs() const;
78 
79  protected:
80 
81  QgsAbstractFeatureSource *mProviderFeatureSource = nullptr;
82 
83  QgsVectorLayerJoinBuffer *mJoinBuffer = nullptr;
84 
85  QgsExpressionFieldBuffer *mExpressionFieldBuffer = nullptr;
86 
88 
90 
92 
93  // A deep-copy is only performed, if the original maps change
94  // see here https://github.com/qgis/Quantum-GIS/pull/673
95  // for explanation
99  QList<QgsField> mAddedAttributes;
102 
104 };
105 
109 class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
110 {
111  public:
112  QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource *source, bool ownSource, const QgsFeatureRequest &request );
113 
115 
117  virtual bool rewind() override;
118 
120  virtual bool close() override;
121 
122  virtual void setInterruptionChecker( QgsInterruptionChecker *interruptionChecker ) override SIP_SKIP;
123 
128  struct CORE_EXPORT FetchJoinInfo
129  {
135  int joinField;
136 
137  void addJoinedAttributesCached( QgsFeature &f, const QVariant &joinValue ) const;
138  void addJoinedAttributesDirect( QgsFeature &f, const QVariant &joinValue ) const;
139  };
140 
141 
142  protected:
144  virtual bool fetchFeature( QgsFeature &feature ) override;
145 
150  virtual bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
151 
153  virtual bool prepareSimplification( const QgsSimplifyMethod &simplifyMethod ) override;
154 
156  void rewindEditBuffer() SIP_SKIP;
157 
159  void prepareJoin( int fieldIdx ) SIP_SKIP;
160 
162  void prepareExpression( int fieldIdx ) SIP_SKIP;
163 
165  void prepareFields() SIP_SKIP;
166 
168  void prepareField( int fieldIdx ) SIP_SKIP;
169 
171  bool fetchNextAddedFeature( QgsFeature &f ) SIP_SKIP;
173  bool fetchNextChangedGeomFeature( QgsFeature &f ) SIP_SKIP;
175  bool fetchNextChangedAttributeFeature( QgsFeature &f ) SIP_SKIP;
177  void useAddedFeature( const QgsFeature &src, QgsFeature &f ) SIP_SKIP;
179  void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry &geom, QgsFeature &f ) SIP_SKIP;
181  bool nextFeatureFid( QgsFeature &f ) SIP_SKIP;
183  void addJoinedAttributes( QgsFeature &f ) SIP_SKIP;
184 
194  void addVirtualAttributes( QgsFeature &f ) SIP_SKIP;
195 
203  void addExpressionAttribute( QgsFeature &f, int attrIndex ) SIP_SKIP;
204 
209  void updateChangedAttributes( QgsFeature &f ) SIP_SKIP;
210 
215  void updateFeatureGeometry( QgsFeature &f ) SIP_SKIP;
216 
221 
224 
225  // only related to editing
226  QSet<QgsFeatureId> mFetchConsidered;
227  QgsGeometryMap::ConstIterator mFetchChangedGeomIt;
228  QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt;
229 
230  bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
231 
235  QMap<const QgsVectorLayerJoinInfo *, QgsVectorLayerFeatureIterator::FetchJoinInfo> mFetchJoinInfo;
236 
237  QMap<int, QgsExpression *> mExpressionFieldInfo;
238 
240 
241  private:
242 #ifdef SIP_RUN
244 #endif
245 
246  std::unique_ptr<QgsExpressionContext> mExpressionContext;
247 
248  QgsInterruptionChecker *mInterruptionChecker = nullptr;
249 
250  QList< int > mPreparedFields;
251  QList< int > mFieldsToPrepare;
252 
254  QList< FetchJoinInfo > mOrderedJoinInfoList;
255 
260  bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
261 
263  virtual bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
264 
265  void createOrderedJoinList();
266 
270  bool postProcessFeature( QgsFeature &feature );
271 
275  bool checkGeometryValidity( const QgsFeature &feature );
276 };
277 
278 
279 
287 {
288  public:
289 
296 
297  QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
298  QgsCoordinateReferenceSystem sourceCrs() const override;
299  QgsFields fields() const override;
300  QgsWkbTypes::Type wkbType() const override;
301  long featureCount() const override;
302  QString sourceName() const override;
303 
304 
305  private:
306 
307  // ideally this wouldn't be mutable, but QgsVectorLayerFeatureSource has non-const getFeatures()
308  mutable QgsVectorLayerFeatureSource mSource;
309  QgsFeatureIds mSelectedFeatureIds;
311  QString mName;
312 
313 };
314 
315 #endif // QGSVECTORLAYERFEATUREITERATOR_H
Wrapper for iterator of features from vector data provider or vector layer.
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
Definition: qgsfeature.h:537
const QgsVectorLayerJoinInfo * joinInfo
Canonical source of information about the join.
virtual bool close()=0
end of iterating: free the resources / lock
A rectangle specified with double values.
Definition: qgsrectangle.h:39
virtual QgsFields fields() const =0
Returns the fields associated with features in the source.
QMap< int, QgsExpression * > mExpressionFieldInfo
QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt
QgsGeometryMap::ConstIterator mFetchChangedGeomIt
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeature.h:544
virtual bool rewind()=0
reset the iterator to the starting position
virtual QgsWkbTypes::Type wkbType() const =0
Returns the geometry type for features returned by this source.
virtual QgsFeatureIterator getFeatures(const QgsFeatureRequest &request=QgsFeatureRequest())=0
Get an iterator for features matching the specified request.
Container of fields for a vector layer.
Definition: qgsfields.h:42
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:94
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:62
QgsVectorLayer * joinLayer
Resolved pointer to the joined layer.
Manages joined fields for a vector layer.
int joinField
Index of field (of the joined layer) must have equal value.
Interface that can be optionally attached to an iterator so its nextFeature() implementaton can check...
Type
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:67
#define SIP_SKIP
Definition: qgis_sip.h:119
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
Defines left outer join from our vector layer to some other vector layer.
This class wraps a request for features to a vector layer (or directly its vector data provider)...
Single scope for storing variables and functions for use within a QgsExpressionContext.
Base class that can be used for any class that is capable of returning features.
virtual QgsCoordinateReferenceSystem sourceCrs() const =0
Returns the coordinate reference system for features in the source.
Partial snapshot of vector layer&#39;s state (only the members necessary for access to features) ...
int indexOffset
At what position the joined fields start.
QMap< QgsFeatureId, QgsFeature > QgsFeatureMap
int targetField
Index of field (of this layer) that drives the join.
Buffers information about expression fields for a vector layer.
virtual void setInterruptionChecker(QgsInterruptionChecker *interruptionChecker)
Attach an object that can be queried regularly by the iterator to check if it must stopped...
QgsFeatureSource subclass for the selected features from a QgsVectorLayer.
QMap< QgsFeatureId, QgsAttributeMap > QgsChangedAttributesMap
Definition: qgsfeature.h:528
An interface for objects which provide features via a getFeatures method.
QMap< const QgsVectorLayerJoinInfo *, QgsVectorLayerFeatureIterator::FetchJoinInfo > mFetchJoinInfo
Information about joins used in the current select() statement.
This class represents a coordinate reference system (CRS).
Class for doing transforms between two map coordinate systems.
Join information prepared for fast attribute id mapping in QgsVectorLayerJoinBuffer::updateFeatureAtt...
qint64 QgsFeatureId
Definition: qgsfeature.h:37
This class contains information about how to simplify geometries fetched from a QgsFeatureIterator.
QList< int > QgsAttributeList
Definition: qgsfield.h:27
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
virtual QString sourceName() const =0
Returns a friendly display name for the source.
Represents a vector layer which manages a vector based data sets.
virtual QgsFeatureIterator getFeatures(const QgsFeatureRequest &request=QgsFeatureRequest()) const =0
Returns an iterator for the features in the source.
Helper template that cares of two things: 1.
virtual long featureCount() const =0
Returns the number of features contained in the source, or -1 if the feature count is unknown...