QGIS API Documentation  2.99.0-Master (7d4f81d)
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 
49 {
50  public:
51 
55  explicit QgsVectorLayerFeatureSource( const QgsVectorLayer *layer );
56 
58 
59  virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) override;
60 
62 
69  QgsFields fields() const;
70 
75  QgsCoordinateReferenceSystem crs() const;
76 
77  protected:
78 
79  QgsAbstractFeatureSource *mProviderFeatureSource = nullptr;
80 
81  QgsVectorLayerJoinBuffer *mJoinBuffer = nullptr;
82 
83  QgsExpressionFieldBuffer *mExpressionFieldBuffer = nullptr;
84 
86 
88 
90 
91  // A deep-copy is only performed, if the original maps change
92  // see here https://github.com/qgis/Quantum-GIS/pull/673
93  // for explanation
97  QList<QgsField> mAddedAttributes;
100 
102 };
103 
106 class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
107 {
108  public:
109  QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource *source, bool ownSource, const QgsFeatureRequest &request );
110 
112 
114  virtual bool rewind() override;
115 
117  virtual bool close() override;
118 
119  virtual void setInterruptionChecker( QgsInterruptionChecker *interruptionChecker ) override SIP_SKIP;
120 
124  struct CORE_EXPORT FetchJoinInfo
125  {
131  int joinField;
132 
133  void addJoinedAttributesCached( QgsFeature &f, const QVariant &joinValue ) const;
134  void addJoinedAttributesDirect( QgsFeature &f, const QVariant &joinValue ) const;
135  };
136 
137 
138  protected:
140  virtual bool fetchFeature( QgsFeature &feature ) override;
141 
144  virtual bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
145 
147  virtual bool prepareSimplification( const QgsSimplifyMethod &simplifyMethod ) override;
148 
150  void rewindEditBuffer() SIP_SKIP;
151 
153  void prepareJoin( int fieldIdx ) SIP_SKIP;
154 
156  void prepareExpression( int fieldIdx ) SIP_SKIP;
157 
159  void prepareFields() SIP_SKIP;
160 
162  void prepareField( int fieldIdx ) SIP_SKIP;
163 
165  bool fetchNextAddedFeature( QgsFeature &f ) SIP_SKIP;
167  bool fetchNextChangedGeomFeature( QgsFeature &f ) SIP_SKIP;
169  bool fetchNextChangedAttributeFeature( QgsFeature &f ) SIP_SKIP;
171  void useAddedFeature( const QgsFeature &src, QgsFeature &f ) SIP_SKIP;
173  void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry &geom, QgsFeature &f ) SIP_SKIP;
175  bool nextFeatureFid( QgsFeature &f ) SIP_SKIP;
177  void addJoinedAttributes( QgsFeature &f ) SIP_SKIP;
178 
188  void addVirtualAttributes( QgsFeature &f ) SIP_SKIP;
189 
196  void addExpressionAttribute( QgsFeature &f, int attrIndex ) SIP_SKIP;
197 
201  void updateChangedAttributes( QgsFeature &f ) SIP_SKIP;
202 
206  void updateFeatureGeometry( QgsFeature &f ) SIP_SKIP;
207 
212 
215 
216  // only related to editing
217  QSet<QgsFeatureId> mFetchConsidered;
218  QgsGeometryMap::ConstIterator mFetchChangedGeomIt;
219  QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt;
220 
221  bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
222 
225  QMap<const QgsVectorLayerJoinInfo *, QgsVectorLayerFeatureIterator::FetchJoinInfo> mFetchJoinInfo;
226 
227  QMap<int, QgsExpression *> mExpressionFieldInfo;
228 
230 
231  private:
232 #ifdef SIP_RUN
234 #endif
235 
236  std::unique_ptr<QgsExpressionContext> mExpressionContext;
237 
238  QgsInterruptionChecker *mInterruptionChecker = nullptr;
239 
240  QList< int > mPreparedFields;
241  QList< int > mFieldsToPrepare;
242 
244  QList< FetchJoinInfo > mOrderedJoinInfoList;
245 
250  bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
251 
253  virtual bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
254 
255  void createOrderedJoinList();
256 
260  bool postProcessFeature( QgsFeature &feature );
261 
265  bool checkGeometryValidity( const QgsFeature &feature );
266 };
267 
268 
269 
277 {
278  public:
279 
286 
287  QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
288  QgsCoordinateReferenceSystem sourceCrs() const override;
289  QgsFields fields() const override;
290  QgsWkbTypes::Type wkbType() const override;
291  long featureCount() const override;
292  QString sourceName() const override;
293 
294 
295  private:
296 
297  // ideally this wouldn't be mutable, but QgsVectorLayerFeatureSource has non-const getFeatures()
298  mutable QgsVectorLayerFeatureSource mSource;
299  QgsFeatureIds mSelectedFeatureIds;
301  QString mName;
302 
303 };
304 
305 #endif // QGSVECTORLAYERFEATUREITERATOR_H
Wrapper for iterator of features from vector data provider or vector layer.
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
Definition: qgsfeature.h:512
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:38
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:519
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:41
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:96
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:61
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:66
#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:503
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...