QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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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
64
66
68
70
76 QgsFields fields() const;
77
82
88 QString id() const;
89
90 protected:
91
92 std::unique_ptr< QgsAbstractFeatureSource > mProviderFeatureSource;
93
94 std::unique_ptr< QgsVectorLayerJoinBuffer > mJoinBuffer;
95
96#ifndef SIP_RUN
97
105 {
106
110 std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;
111
116 };
117
119 QMap< QString, JoinLayerSource > mJoinSources;
120#endif
121
122 std::unique_ptr< QgsExpressionFieldBuffer > mExpressionFieldBuffer;
123
125
126 QString mId;
127
129
131
132 // A deep-copy is only performed, if the original maps change
133 // see here https://github.com/qgis/Quantum-GIS/pull/673
134 // for explanation
138 QList<QgsField> mAddedAttributes;
141
143
144 private:
145#ifdef SIP_RUN
147#endif
148};
149
154class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsVectorLayerFeatureSource>
155{
156 public:
157 QgsVectorLayerFeatureIterator( QgsVectorLayerFeatureSource *source, bool ownSource, const QgsFeatureRequest &request );
158
160
162 bool rewind() override;
163
165 bool close() override;
166
167 void setInterruptionChecker( QgsFeedback *interruptionChecker ) override SIP_SKIP;
168
173 struct CORE_EXPORT FetchJoinInfo
174 {
180 QMap<int, int> attributesSourceToDestLayerMap SIP_SKIP;
183
184#ifndef SIP_RUN
185
192 std::shared_ptr< QgsVectorLayerFeatureSource > joinSource;
193
201#endif
202
205
208
209 void addJoinedAttributesCached( QgsFeature &f, const QVariant &joinValue ) const;
210 void addJoinedAttributesDirect( QgsFeature &f, const QVariant &joinValue ) const;
211 };
212
213 bool isValid() const override;
214
215 protected:
217 bool fetchFeature( QgsFeature &feature ) override;
218
223 bool nextFeatureFilterExpression( QgsFeature &f ) override { return fetchFeature( f ); }
224
226 bool prepareSimplification( const QgsSimplifyMethod &simplifyMethod ) override;
227
229 void rewindEditBuffer() SIP_SKIP;
230
232 void prepareJoin( int fieldIdx ) SIP_SKIP;
233
235 void prepareExpression( int fieldIdx ) SIP_SKIP;
236
238 void prepareFields() SIP_SKIP;
239
241 void prepareField( int fieldIdx ) SIP_SKIP;
242
244 bool fetchNextAddedFeature( QgsFeature &f ) SIP_SKIP;
246 bool fetchNextChangedGeomFeature( QgsFeature &f ) SIP_SKIP;
248 bool fetchNextChangedAttributeFeature( QgsFeature &f ) SIP_SKIP;
250 void useAddedFeature( const QgsFeature &src, QgsFeature &f ) SIP_SKIP;
252 void useChangedAttributeFeature( QgsFeatureId fid, const QgsGeometry &geom, QgsFeature &f ) SIP_SKIP;
254 bool nextFeatureFid( QgsFeature &f ) SIP_SKIP;
256 void addJoinedAttributes( QgsFeature &f ) SIP_SKIP;
257
268 void addVirtualAttributes( QgsFeature &f ) SIP_SKIP;
269
276 void addExpressionAttribute( QgsFeature &f, int attrIndex ) SIP_SKIP;
277
282 void updateChangedAttributes( QgsFeature &f ) SIP_SKIP;
283
288 void updateFeatureGeometry( QgsFeature &f ) SIP_SKIP;
289
290 QgsFeatureRequest mProviderRequest;
291 QgsFeatureIterator mProviderIterator;
292 QgsFeatureRequest mChangedFeaturesRequest;
293 QgsFeatureIterator mChangedFeaturesIterator;
294
295 // filter bounding box constraint, in SOURCE CRS
296 QgsRectangle mFilterRect;
297 bool mHasValidTransform = false;
299
300 // distance within constraint reference geometry and distance IN DESTINATION CRS
301 QgsGeometry mDistanceWithinGeom;
302 std::shared_ptr< QgsGeometryEngine > mDistanceWithinEngine;
303 double mDistanceWithin = 0;
304
305 // only related to editing
306 QSet<QgsFeatureId> mFetchConsidered;
307 QgsGeometryMap::ConstIterator mFetchChangedGeomIt;
308 QgsFeatureMap::ConstIterator mFetchAddedFeaturesIt;
309
310 bool mFetchedFid; // when iterating by FID: indicator whether it has been fetched yet or not
311
317
318 QMap<int, QgsExpression *> mExpressionFieldInfo;
319
320 bool mHasVirtualAttributes;
321
322 private:
323#ifdef SIP_RUN
325#endif
326
327 void createExpressionContext();
328 std::unique_ptr<QgsExpressionContext> mExpressionContext;
329
330 QgsFeedback *mInterruptionChecker = nullptr;
331
332 QList< int > mPreparedFields;
333 QList< int > mFieldsToPrepare;
334
336 QList< FetchJoinInfo > mOrderedJoinInfoList;
337
342 bool prepareOrderBy( const QList<QgsFeatureRequest::OrderByClause> &orderBys ) override;
343
345 bool providerCanSimplify( QgsSimplifyMethod::MethodType methodType ) const override;
346
347 void createOrderedJoinList();
348
352 bool postProcessFeature( QgsFeature &feature );
353
357 bool checkGeometryValidity( const QgsFeature &feature );
358
359 bool mDelegatedOrderByToProvider = false;
360};
361
362
363
370{
371 public:
372
379
382
383 QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
384 QgsCoordinateReferenceSystem sourceCrs() const override;
385 QgsFields fields() const override;
386 Qgis::WkbType wkbType() const override;
387 long long featureCount() const override;
388 QString sourceName() const override;
389 QgsExpressionContextScope *createExpressionContextScope() const override;
390 Qgis::SpatialIndexPresence hasSpatialIndex() const override;
391
392 private:
393
394#ifdef SIP_RUN
396#endif
397
398 // ideally this wouldn't be mutable, but QgsVectorLayerFeatureSource has non-const getFeatures()
399 mutable QgsVectorLayerFeatureSource mSource;
400 QgsFeatureIds mSelectedFeatureIds;
402 QString mName;
403 QPointer< QgsVectorLayer > mLayer;
404
405};
406
408
409#ifndef SIP_RUN
410class QgsVectorLayerSelectedFeatureIterator : public QgsAbstractFeatureIterator
411{
412 public:
413
414 QgsVectorLayerSelectedFeatureIterator( const QgsFeatureIds &selectedFeatureIds,
415 const QgsFeatureRequest &request,
417
418 bool rewind() override;
419 bool close() override;
420
421 protected:
422 bool fetchFeature( QgsFeature &f ) override;
423
424 private:
425 QgsFeatureIds mSelectedFeatureIds;
426 QgsFeatureIterator mIterator;
427
428};
429
430#endif
431
433
434#endif // QGSVECTORLAYERFEATUREITERATOR_H
SpatialIndexPresence
Enumeration of spatial index presence states.
Definition qgis.h:522
WkbType
The WKB type describes the number of dimensions a geometry has.
Definition qgis.h:256
@ Unknown
Unknown.
Helper template that cares of two things: 1.
Internal feature iterator to be implemented within data providers.
virtual bool rewind()=0
Resets 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
Call to end the iteration.
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.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:58
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition qgsfeedback.h:44
Container of fields for a vector layer.
Definition qgsfields.h:46
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.
A rectangle specified with double values.
This class contains information about how to simplify geometries fetched from a QgsFeatureIterator.
Stores queued vector layer edit operations prior to committing changes to the layer's data provider.
A feature iterator which iterates over features from a QgsVectorLayer.
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
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
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 & operator==(const QgsVectorLayerSelectedFeatureSource &other)=delete
Represents a vector layer which manages a vector based data sets.
#define SIP_SKIP
Definition qgis_sip.h:126
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
QMap< QgsFeatureId, QgsAttributeMap > QgsChangedAttributesMap
QSet< QgsFeatureId > QgsFeatureIds
qint64 QgsFeatureId
64 bit feature ids negative numbers are used for uncommitted/newly added features
QList< int > QgsAttributeList
Definition qgsfield.h:27
QMap< QgsFeatureId, QgsFeature > QgsFeatureMap
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.