QGIS API Documentation 3.28.0-Firenze (ed3ad0430f)
Go to the documentation of this file.
2 memoryprovider.h - provider with storage in memory
3 ------------------
4 begin : June 2008
5 copyright : (C) 2008 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 ***************************************************************************/
16#define SIP_NO_FILE
20#include "qgsfields.h"
21#include "qgsprovidermetadata.h"
24typedef QMap<QgsFeatureId, QgsFeature> QgsFeatureMap;
26class QgsSpatialIndex;
28class QgsMemoryFeatureIterator;
30class QgsMemoryProvider final: public QgsVectorDataProvider
34 public:
35 explicit QgsMemoryProvider( const QString &uri, const QgsVectorDataProvider::ProviderOptions &coordinateTransformContext,
36 QgsDataProvider::ReadFlags flags = QgsDataProvider::ReadFlags() );
38 ~QgsMemoryProvider() override;
41 static QString providerKey();
43 static QString providerDescription();
45 /* Implementation of functions from QgsVectorDataProvider */
49 QString dataSourceUri( bool expandAuthConfig = true ) const override;
50 QString storageType() const override;
51 QgsFeatureIterator getFeatures( const QgsFeatureRequest &request ) const override;
52 QgsWkbTypes::Type wkbType() const override;
53 long long featureCount() const override;
54 QgsFields fields() const override;
55 bool addFeatures( QgsFeatureList &flist, QgsFeatureSink::Flags flags = QgsFeatureSink::Flags() ) override;
56 bool deleteFeatures( const QgsFeatureIds &id ) override;
57 bool addAttributes( const QList<QgsField> &attributes ) override;
58 bool renameAttributes( const QgsFieldNameMap &renamedAttributes ) override;
59 bool deleteAttributes( const QgsAttributeIds &attributes ) override;
60 bool changeAttributeValues( const QgsChangedAttributesMap &attr_map ) override;
61 bool changeGeometryValues( const QgsGeometryMap &geometry_map ) override;
62 QString subsetString() const override;
63 bool setSubsetString( const QString &theSQL, bool updateFeatureCount = true ) override;
64 bool supportsSubsetString() const override { return true; }
65 bool createSpatialIndex() override;
67 QgsVectorDataProvider::Capabilities capabilities() const override;
68 bool truncate() override;
70 /* Implementation of functions from QgsDataProvider */
72 QString name() const override;
73 QString description() const override;
74 QgsRectangle extent() const override;
75 void updateExtents() override;
76 bool isValid() const override;
77 QgsCoordinateReferenceSystem crs() const override;
78 void handlePostCloneOperations( QgsVectorDataProvider *source ) override;
80 private:
81 // Coordinate reference system
84 // fields
85 QgsFields mFields;
86 QgsWkbTypes::Type mWkbType;
87 mutable QgsRectangle mExtent;
89 // features
90 QgsFeatureMap mFeatures;
91 QgsFeatureId mNextFeatureId;
93 // indexing
94 QgsSpatialIndex *mSpatialIndex = nullptr;
96 QString mSubsetString;
98 friend class QgsMemoryFeatureSource;
102class QgsMemoryProviderMetadata final: public QgsProviderMetadata
106 public:
107 QgsMemoryProviderMetadata();
108 QIcon icon() const override;
109 QgsDataProvider *createProvider( const QString &uri, const QgsDataProvider::ProviderOptions &options, QgsDataProvider::ReadFlags flags = QgsDataProvider::ReadFlags() ) override;
110 QList< QgsMapLayerType > supportedLayerTypes() const override;
Base class that can be used for any class that is capable of returning features.
This class represents a coordinate reference system (CRS).
Abstract base class for spatial data provider implementations.
virtual QString name() const =0
Returns a provider name.
virtual QgsCoordinateReferenceSystem crs() const =0
Returns the coordinate system for the data source.
virtual QString subsetString() const
Returns the subset definition string (typically sql) currently in use by the layer and used by the pr...
virtual bool isValid() const =0
Returns true if this is a valid layer.
virtual bool supportsSubsetString() const
Returns true if the provider supports setting of subset strings.
virtual QString dataSourceUri(bool expandAuthConfig=false) const
Gets the data source specification.
virtual QString description() const =0
Returns description.
virtual void updateExtents()
Update the extents of the layer.
virtual bool setSubsetString(const QString &subset, bool updateFeatureCount=true)
Set the subset string used to create a subset of features in the layer.
virtual QgsRectangle extent() const =0
Returns the extent of the layer.
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).
Enumeration of spatial index presence states.
virtual SpatialIndexPresence hasSpatialIndex() const
Returns an enum value representing the presence of a valid spatial index on the source,...
Container of fields for a vector layer.
Definition: qgsfields.h:45
Holds data provider key, description, and associated shared library file or function pointer informat...
virtual QIcon icon() const
Returns an icon representing the provider.
virtual QgsDataProvider * createProvider(const QString &uri, const QgsDataProvider::ProviderOptions &options, QgsDataProvider::ReadFlags flags=QgsDataProvider::ReadFlags())
Class factory to return a pointer to a newly created QgsDataProvider object.
virtual QList< QgsMapLayerType > supportedLayerTypes() const
Returns a list of the map layer types supported by the provider.
A rectangle specified with double values.
Definition: qgsrectangle.h:42
A spatial index for QgsFeature objects.
This is the base class for vector data providers.
QgsWkbTypes::Type wkbType() const override=0
Returns the geometry type which is returned by this layer.
virtual bool changeGeometryValues(const QgsGeometryMap &geometry_map)
Changes geometries of existing features.
virtual bool createSpatialIndex()
Creates a spatial index on the datasource (if supported by the provider type).
long long featureCount() const override=0
Number of features in the layer.
virtual QString storageType() const
Returns the permanent storage type for this layer as a friendly name.
virtual bool truncate()
Removes all features from the layer.
virtual void handlePostCloneOperations(QgsVectorDataProvider *source)
Handles any post-clone operations required after this vector data provider was cloned from the source...
virtual QgsAbstractFeatureSource * featureSource() const =0
Returns feature source object that can be used for querying provider's data.
virtual bool changeAttributeValues(const QgsChangedAttributesMap &attr_map)
Changes attribute values of existing features.
virtual bool deleteFeatures(const QgsFeatureIds &id)
Deletes one or more features from the provider.
bool addFeatures(QgsFeatureList &flist, QgsFeatureSink::Flags flags=QgsFeatureSink::Flags()) override
Adds a list of features to the sink.
QgsFields fields() const override=0
Returns the fields associated with this data provider.
QgsFeatureIterator getFeatures(const QgsFeatureRequest &request=QgsFeatureRequest()) const override=0
Query the provider for features specified in request.
virtual bool addAttributes(const QList< QgsField > &attributes)
Adds new attributes to the provider.
virtual Q_INVOKABLE QgsVectorDataProvider::Capabilities capabilities() const
Returns flags containing the supported capabilities.
virtual bool renameAttributes(const QgsFieldNameMap &renamedAttributes)
Renames existing attributes.
virtual bool deleteAttributes(const QgsAttributeIds &attributes)
Deletes existing attributes from the provider.
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:70
QMap< int, QString > QgsFieldNameMap
Definition: qgsattributes.h:45
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
Definition: qgsfeature.h:917
QMap< QgsFeatureId, QgsAttributeMap > QgsChangedAttributesMap
Definition: qgsfeature.h:908
QList< QgsFeature > QgsFeatureList
Definition: qgsfeature.h:922
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
QSet< int > QgsAttributeIds
QMap< QgsFeatureId, QgsFeature > QgsFeatureMap
Setting options for creating vector data providers.