QgsFeatureSource subclass which proxies methods to an underlying QgsFeatureSource, modifying results according to the settings in a QgsProcessingContext. More...

#include <qgsprocessingutils.h>

Inheritance diagram for QgsProcessingFeatureSource:

[legend]

Public Types
enum	Flag { FlagSkipGeometryValidityChecks = 1 << 1 }
	Flags controlling how QgsProcessingFeatureSource fetches features. More...

Public Types inherited from QgsFeatureSource
enum	FeatureAvailability { NoFeaturesAvailable , FeaturesAvailable , FeaturesMaybeAvailable }
	Possible return value for hasFeatures() to determine if a source is empty. More...

enum	SpatialIndexPresence { SpatialIndexUnknown = 0 , SpatialIndexNotPresent = 1 , SpatialIndexPresent = 2 }
	Enumeration of spatial index presence states. More...

Public Member Functions
	QgsProcessingFeatureSource (QgsFeatureSource *originalSource, const QgsProcessingContext &context, bool ownsOriginalSource=false, long long featureLimit=-1, const QString &filterExpression=QString())
	Constructor for QgsProcessingFeatureSource, accepting an original feature source originalSource and processing context.

	~QgsProcessingFeatureSource () override

QgsFeatureIds	allFeatureIds () const override
	Returns a list of all feature IDs for features present in the source.

QgsExpressionContextScope *	createExpressionContextScope () const
	Returns an expression context scope suitable for this source.

long long	featureCount () const override
	Returns the number of features contained in the source, or -1 if the feature count is unknown.

QgsFields	fields () const override
	Returns the fields associated with features in the source.

QgsFeatureIterator	getFeatures (const QgsFeatureRequest &request, Flags flags) const
	Returns an iterator for the features in the source, respecting the supplied feature flags.

QgsFeatureIterator	getFeatures (const QgsFeatureRequest &request=QgsFeatureRequest()) const override
	Returns an iterator for the features in the source.

QgsFeatureSource::FeatureAvailability	hasFeatures () const override
	Determines if there are any features available in the source.

SpatialIndexPresence	hasSpatialIndex () const override
	Returns an enum value representing the presence of a valid spatial index on the source, if it can be determined.

QVariant	maximumValue (int fieldIndex) const override
	Returns the maximum value for an attribute column or an invalid variant in case of error.

QVariant	minimumValue (int fieldIndex) const override
	Returns the minimum value for an attribute column or an invalid variant in case of error.

void	setInvalidGeometryCheck (QgsFeatureRequest::InvalidGeometryCheck method)
	Overrides the default geometry check method for the source.

QgsCoordinateReferenceSystem	sourceCrs () const override
	Returns the coordinate reference system for features in the source.

QgsRectangle	sourceExtent () const override
	Returns the extent of all geometries from the source.

QString	sourceName () const override
	Returns a friendly display name for the source.

QSet< QVariant >	uniqueValues (int fieldIndex, int limit=-1) const override
	Returns the set of unique values contained within the specified fieldIndex from this source.

Qgis::WkbType	wkbType () const override
	Returns the geometry type for features returned by this source.

Public Member Functions inherited from QgsFeatureSource
virtual	~QgsFeatureSource ()=default

QgsVectorLayer *	materialize (const QgsFeatureRequest &request, QgsFeedback *feedback=nullptr)
	Materializes a request (query) made against this feature source, by running it over the source and returning a new memory based vector layer containing the result.

Detailed Description

QgsFeatureSource subclass which proxies methods to an underlying QgsFeatureSource, modifying results according to the settings in a QgsProcessingContext.

Since: QGIS 3.0

Definition at line 675 of file qgsprocessingutils.h.

Member Enumeration Documentation

◆ Flag

enum QgsProcessingFeatureSource::Flag

Flags controlling how QgsProcessingFeatureSource fetches features.

Enumerator
FlagSkipGeometryValidityChecks	Invalid geometry checks should always be skipped. This flag can be useful for algorithms which always require invalid geometries, regardless of any user settings (e.g. "repair geometry" type algorithms).

Definition at line 680 of file qgsprocessingutils.h.

Constructor & Destructor Documentation

◆ QgsProcessingFeatureSource()

QgsProcessingFeatureSource::QgsProcessingFeatureSource	(	QgsFeatureSource *	originalSource,
		const QgsProcessingContext &	context,
		bool	ownsOriginalSource = `false`,
		long long	featureLimit = `-1`,
		const QString &	filterExpression = `QString()`
	)

Constructor for QgsProcessingFeatureSource, accepting an original feature source originalSource and processing context.

Ownership of originalSource is dictated by ownsOriginalSource. If ownsOriginalSource is false, ownership is not transferred, and callers must ensure that originalSource exists for the lifetime of this object. If ownsOriginalSource is true, then this object will take ownership of originalSource.

If featureLimit is set to a value > 0, then a limit is placed on the maximum number of features which will be read from the source.

Since QGIS 3.32, the optional filterExpression can be used to specify an expression based filter for the source.

Definition at line 1596 of file qgsprocessingutils.cpp.

◆ ~QgsProcessingFeatureSource()

QgsProcessingFeatureSource::~QgsProcessingFeatureSource ( )

override

Definition at line 1616 of file qgsprocessingutils.cpp.

Member Function Documentation

◆ allFeatureIds()

QgsFeatureIds QgsProcessingFeatureSource::allFeatureIds ( ) const

overridevirtual

Returns a list of all feature IDs for features present in the source.

Reimplemented from QgsFeatureSource.

Definition at line 1795 of file qgsprocessingutils.cpp.

◆ createExpressionContextScope()

QgsExpressionContextScope * QgsProcessingFeatureSource::createExpressionContextScope ( ) const

Returns an expression context scope suitable for this source.

Definition at line 1821 of file qgsprocessingutils.cpp.

◆ featureCount()

long long QgsProcessingFeatureSource::featureCount ( ) const

overridevirtual

Returns the number of features contained in the source, or -1 if the feature count is unknown.

Implements QgsFeatureSource.

Definition at line 1691 of file qgsprocessingutils.cpp.

◆ fields()

QgsFields QgsProcessingFeatureSource::fields ( ) const

overridevirtual

Returns the fields associated with features in the source.

Implements QgsFeatureSource.

Definition at line 1681 of file qgsprocessingutils.cpp.

◆ getFeatures() [1/2]

QgsFeatureIterator QgsProcessingFeatureSource::getFeatures	(	const QgsFeatureRequest &	request,
		Flags	flags
	)		const

Returns an iterator for the features in the source, respecting the supplied feature flags.

An optional request can be used to optimise the returned iterator, eg by restricting the returned attributes or geometry.

Definition at line 1622 of file qgsprocessingutils.cpp.

◆ getFeatures() [2/2]

QgsFeatureIterator QgsProcessingFeatureSource::getFeatures ( const QgsFeatureRequest & request = QgsFeatureRequest() ) const

overridevirtual

Returns an iterator for the features in the source.

An optional request can be used to optimise the returned iterator, eg by restricting the returned attributes or geometry.

Implements QgsFeatureSource.

Definition at line 1658 of file qgsprocessingutils.cpp.

◆ hasFeatures()

QgsFeatureSource::FeatureAvailability QgsProcessingFeatureSource::hasFeatures ( ) const

overridevirtual

Determines if there are any features available in the source.

Since: QGIS 3.2

Reimplemented from QgsFeatureSource.

Definition at line 1646 of file qgsprocessingutils.cpp.

◆ hasSpatialIndex()

QgsFeatureSource::SpatialIndexPresence QgsProcessingFeatureSource::hasSpatialIndex ( ) const

overridevirtual

Returns an enum value representing the presence of a valid spatial index on the source, if it can be determined.

If QgsFeatureSource::SpatialIndexUnknown is returned then the presence of an index cannot be determined.

Since: QGIS 3.10.1

Reimplemented from QgsFeatureSource.

Definition at line 1816 of file qgsprocessingutils.cpp.

◆ maximumValue()

QVariant QgsProcessingFeatureSource::maximumValue ( int fieldIndex ) const

overridevirtual

Returns the maximum value for an attribute column or an invalid variant in case of error.

The base class implementation uses a non-optimised approach of looping through all features in the source.

See also: minimumValue(); uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 1762 of file qgsprocessingutils.cpp.

◆ minimumValue()

QVariant QgsProcessingFeatureSource::minimumValue ( int fieldIndex ) const

overridevirtual

Returns the minimum value for an attribute column or an invalid variant in case of error.

The base class implementation uses a non-optimised approach of looping through all features in the source.

See also: maximumValue(); uniqueValues()

Reimplemented from QgsFeatureSource.

Definition at line 1734 of file qgsprocessingutils.cpp.

◆ setInvalidGeometryCheck()

void QgsProcessingFeatureSource::setInvalidGeometryCheck ( QgsFeatureRequest::InvalidGeometryCheck method )

Overrides the default geometry check method for the source.

Since: QGIS 3.14

Definition at line 1832 of file qgsprocessingutils.cpp.

◆ sourceCrs()

QgsCoordinateReferenceSystem QgsProcessingFeatureSource::sourceCrs ( ) const

overridevirtual

Returns the coordinate reference system for features in the source.

Implements QgsFeatureSource.

Definition at line 1676 of file qgsprocessingutils.cpp.

◆ sourceExtent()

QgsRectangle QgsProcessingFeatureSource::sourceExtent ( ) const

overridevirtual

Returns the extent of all geometries from the source.

The base class implementation uses a non-optimised approach of looping through all features in the source.

Reimplemented from QgsFeatureSource.

Definition at line 1790 of file qgsprocessingutils.cpp.

◆ sourceName()

QString QgsProcessingFeatureSource::sourceName ( ) const

overridevirtual

Returns a friendly display name for the source.

The returned value can be an empty string.

Implements QgsFeatureSource.

Definition at line 1702 of file qgsprocessingutils.cpp.

◆ uniqueValues()

QSet< QVariant > QgsProcessingFeatureSource::uniqueValues	(	int	fieldIndex,
		int	limit = `-1`
	)		const

overridevirtual

Returns the set of unique values contained within the specified fieldIndex from this source.

If specified, the limit option can be used to limit the number of returned values. The base class implementation uses a non-optimised approach of looping through all features in the source.

See also: minimumValue(); maximumValue()

Reimplemented from QgsFeatureSource.

Definition at line 1707 of file qgsprocessingutils.cpp.

◆ wkbType()

Qgis::WkbType QgsProcessingFeatureSource::wkbType ( ) const

overridevirtual

Returns the geometry type for features returned by this source.

Implements QgsFeatureSource.

Definition at line 1686 of file qgsprocessingutils.cpp.

The documentation for this class was generated from the following files:

/build/qgis-3.34.0+99sid/src/core/processing/qgsprocessingutils.h
/build/qgis-3.34.0+99sid/src/core/processing/qgsprocessingutils.cpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ Flag

Constructor & Destructor Documentation

◆ QgsProcessingFeatureSource()

◆ ~QgsProcessingFeatureSource()

Member Function Documentation

◆ allFeatureIds()

◆ createExpressionContextScope()

◆ featureCount()

◆ fields()

◆ getFeatures() [1/2]

◆ getFeatures() [2/2]

◆ hasFeatures()

◆ hasSpatialIndex()

◆ maximumValue()

◆ minimumValue()

◆ setInvalidGeometryCheck()

◆ sourceCrs()

◆ sourceExtent()

◆ sourceName()

◆ uniqueValues()

◆ wkbType()