QGIS API Documentation 3.29.0-Master (19d7edcfed)
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"
26
27#include <QPointer>
28#include <QSet>
29#include <memory>
30
31typedef QMap<QgsFeatureId, QgsFeature> QgsFeatureMap SIP_SKIP;
32
34class QgsVectorLayer;
39
41
42#ifdef SIP_RUN
43% ModuleHeaderCode
44#include "qgsfeatureiterator.h"
45% End
46#endif
47
53{
54 public:
55
60 explicit QgsVectorLayerFeatureSource( const QgsVectorLayer *layer );
61
66
68
70
72
79 QgsFields fields() const;
80
86
92 QString id() const;
93
94 protected:
95
96 std::unique_ptr< QgsAbstractFeatureSource > mProviderFeatureSource;
97
98 std::unique_ptr< QgsVectorLayerJoinBuffer > mJoinBuffer;
99
100#ifndef SIP_RUN
101
109 {
110
114 std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;
115
120 };
121
123 QMap< QString, JoinLayerSource > mJoinSources;
124#endif
125
126 std::unique_ptr< QgsExpressionFieldBuffer > mExpressionFieldBuffer;
127
129
130 QString mId;
131
133
135
136 // A deep-copy is only performed, if the original maps change
137 // see here https://github.com/qgis/Quantum-GIS/pull/673
138 // for explanation
142 QList<QgsField> mAddedAttributes;
145
147
148 private:
149#ifdef SIP_RUN
151#endif
152};
153
157class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
158{
159 public:
160 QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource *source, bool ownSource, const QgsFeatureRequest &request );
161
163
165 bool rewind() override;
166
168 bool close() override;
169
170 void setInterruptionChecker( QgsFeedback *interruptionChecker ) override SIP_SKIP;
171
176 struct CORE_EXPORT FetchJoinInfo
177 {
183 QMap<int, int> attributesSourceToDestLayerMap SIP_SKIP;
186
187#ifndef SIP_RUN
188
195 std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;
196
204#endif
205
208
211
212 void addJoinedAttributesCached( QgsFeature &f, const QVariant &joinValue ) const;
213 void addJoinedAttributesDirect( QgsFeature &f, const QVariant &joinValue ) const;
214 };
215
216 bool isValid() const override;
217
218 protected:
220 bool fetchFeature( QgsFeature &feature ) override;
221
226 bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
227
229 bool prepareSimplification( const QgsSimplifyMethod &simplifyMethod ) override;
230
232 void rewindEditBuffer() SIP_SKIP;
233
235 void prepareJoin( int fieldIdx ) SIP_SKIP;
236
238 void prepareExpression( int fieldIdx ) SIP_SKIP;
239
241 void prepareFields() SIP_SKIP;
242
244 void prepareField( int fieldIdx ) SIP_SKIP;
245
247 bool fetchNextAddedFeature( QgsFeature &f ) SIP_SKIP;
249 bool fetchNextChangedGeomFeature( QgsFeature &f ) SIP_SKIP;
251 bool fetchNextChangedAttributeFeature( QgsFeature &f ) SIP_SKIP;
253 void useAddedFeature( const QgsFeature &src, QgsFeature &f ) SIP_SKIP;
255 void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry &geom, QgsFeature &f ) SIP_SKIP;
257 bool nextFeatureFid( QgsFeature &f ) SIP_SKIP;
259 void addJoinedAttributes( QgsFeature &f ) SIP_SKIP;
260
271 void addVirtualAttributes( QgsFeature &f ) SIP_SKIP;
272
280 void addExpressionAttribute( QgsFeature &f, int attrIndex ) SIP_SKIP;
281
286 void updateChangedAttributes( QgsFeature &f ) SIP_SKIP;
287
292 void updateFeatureGeometry( QgsFeature &f ) SIP_SKIP;
293
294 QgsFeatureRequest mProviderRequest;
295 QgsFeatureIterator mProviderIterator;
296 QgsFeatureRequest mChangedFeaturesRequest;
297 QgsFeatureIterator mChangedFeaturesIterator;
298
299 // filter bounding box constraint, in SOURCE CRS
300 QgsRectangle mFilterRect;
302
303 // distance within constraint reference geometry and distance IN DESTINATION CRS
304 QgsGeometry mDistanceWithinGeom;
305 std::shared_ptr< QgsGeometryEngine > mDistanceWithinEngine;
306 double mDistanceWithin = 0;
307
308 // only related to editing
309 QSet<QgsFeatureId> mFetchConsidered;
310 QgsGeometryMap::ConstIterator mFetchChangedGeomIt;
311 QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt;
312
313 bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
314
320
321 QMap<int, QgsExpression *> mExpressionFieldInfo;
322
323 bool mHasVirtualAttributes;
324
325 private:
326#ifdef SIP_RUN
328#endif
329
330 void createExpressionContext();
331 std::unique_ptr<QgsExpressionContext> mExpressionContext;
332
333 QgsFeedback *mInterruptionChecker = nullptr;
334
335 QList< int > mPreparedFields;
336 QList< int > mFieldsToPrepare;
337
339 QList< FetchJoinInfo > mOrderedJoinInfoList;
340
345 bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
346
348 bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
349
350 void createOrderedJoinList();
351
355 bool postProcessFeature( QgsFeature &feature );
356
360 bool checkGeometryValidity( const QgsFeature &feature );
361
362 bool mDelegatedOrderByToProvider = false;
363};
364
365
366
374{
375 public:
376
383
388
389 QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
390 QgsCoordinateReferenceSystem sourceCrs() const override;
391 QgsFields fields() const override;
392 QgsWkbTypes::Type wkbType() const override;
393 long long featureCount() const override;
394 QString sourceName() const override;
395 QgsExpressionContextScope *createExpressionContextScope() const override;
396 SpatialIndexPresence hasSpatialIndex() const override;
397
398 private:
399
400#ifdef SIP_RUN
402#endif
403
404 // ideally this wouldn't be mutable, but QgsVectorLayerFeatureSource has non-const getFeatures()
405 mutable QgsVectorLayerFeatureSource mSource;
406 QgsFeatureIds mSelectedFeatureIds;
408 QString mName;
409 QPointer< QgsVectorLayer > mLayer;
410
411};
412
414
415#ifndef SIP_RUN
416class QgsVectorLayerSelectedFeatureIterator : public QgsAbstractFeatureIterator
417{
418 public:
419
420 QgsVectorLayerSelectedFeatureIterator( const QgsFeatureIds &selectedFeatureIds,
421 const QgsFeatureRequest &request,
423
424 bool rewind() override;
425 bool close() override;
426
427 protected:
428 bool fetchFeature( QgsFeature &f ) override;
429
430 private:
431 QgsFeatureIds mSelectedFeatureIds;
432 QgsFeatureIterator mIterator;
433
434};
435
436#endif
437
439
440#endif // QGSVECTORLAYERFEATUREITERATOR_H
Helper template that cares of two things: 1.
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
Base class that can be used for any class that is capable of returning features.
virtual QgsFeatureIterator getFeatures(const QgsFeatureRequest &request=QgsFeatureRequest())=0
Gets an iterator for features matching the specified request.
This class represents a coordinate reference system (CRS).
Class for doing transforms between two map coordinate systems.
Abstract interface for generating an expression context scope.
Single scope for storing variables and functions for use within a QgsExpressionContext.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
Buffers information about expression fields for a vector layer.
Class for parsing and evaluation of expressions (formerly called "search strings").
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).
An interface for objects which provide features via a getFeatures method.
SpatialIndexPresence
Enumeration of spatial index presence states.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition: qgsfeedback.h:45
Container of fields for a vector layer.
Definition: qgsfields.h:45
A geometry engine is a low-level representation of a QgsAbstractGeometry object, optimised for use wi...
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:164
A rectangle specified with double values.
Definition: qgsrectangle.h:42
This class contains information about how to simplify geometries fetched from a QgsFeatureIterator.
bool nextFeatureFilterExpression(QgsFeature &f) override
Overrides default method as we only need to filter features in the edit buffer while for others filte...
Partial snapshot of vector layer's state (only the members necessary for access to features)
QgsChangedAttributesMap mChangedAttributeValues
std::unique_ptr< QgsAbstractFeatureSource > mProviderFeatureSource
~QgsVectorLayerFeatureSource() override
QgsVectorLayerFeatureSource(const QgsVectorLayerFeatureSource &other)=delete
QgsVectorLayerFeatureSource cannot be copied.
std::unique_ptr< QgsVectorLayerJoinBuffer > mJoinBuffer
std::unique_ptr< QgsExpressionFieldBuffer > mExpressionFieldBuffer
QMap< QString, JoinLayerSource > mJoinSources
Contains prepared join sources by layer ID.
QgsVectorLayerFeatureSource & operator==(const QgsVectorLayerFeatureSource &other)=delete
QgsVectorLayerFeatureSource cannot be copied.
Manages joined fields for a vector layer.
Defines left outer join from our vector layer to some other vector layer.
QgsFeatureSource subclass for the selected features from a QgsVectorLayer.
QgsVectorLayerSelectedFeatureSource(const QgsVectorLayerSelectedFeatureSource &other)=delete
QgsVectorLayerSelectedFeatureSource cannot be copied.
QgsVectorLayerSelectedFeatureSource & operator==(const QgsVectorLayerSelectedFeatureSource &other)=delete
QgsVectorLayerSelectedFeatureSource cannot be copied.
Represents a vector layer which manages a vector based data sets.
Type
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:70
#define SIP_SKIP
Definition: qgis_sip.h:126
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
Definition: qgsfeature.h:915
QMap< QgsFeatureId, QgsAttributeMap > QgsChangedAttributesMap
Definition: qgsfeature.h:906
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeatureid.h:37
qint64 QgsFeatureId
64 bit feature ids negative numbers are used for uncommitted/newly added features
Definition: qgsfeatureid.h:28
QList< int > QgsAttributeList
Definition: qgsfield.h:26
QMap< QgsFeatureId, QgsFeature > QgsFeatureMap
const QgsCoordinateReferenceSystem & crs
Join information prepared for fast attribute id mapping in QgsVectorLayerJoinBuffer::updateFeatureAtt...
std::shared_ptr< QgsVectorLayerFeatureSource > joinSource
Feature source for join.
int targetField
Index of field (of this layer) that drives the join.
const QgsVectorLayerJoinInfo * joinInfo
Canonical source of information about the join.
int indexOffset
At what position the joined fields start.
Contains join layer source information prepared in a thread-safe way, ready for vector layer feature ...
std::shared_ptr< QgsVectorLayerFeatureSource > joinSource
Feature source for join.