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:

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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...

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

	~QgsProcessingFeatureSource () override

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

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

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

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

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

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

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

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

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

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

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

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

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

QgsWkbTypes::Type	wkbType () const override
	Returns the geometry type for features returned by this source. More...

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. More...

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 305 of file qgsprocessingutils.h.

Member Enumeration Documentation

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 310 of file qgsprocessingutils.h.

Constructor & Destructor Documentation

QgsProcessingFeatureSource::QgsProcessingFeatureSource	(	QgsFeatureSource *	originalSource,
		const QgsProcessingContext &	context,
		bool	ownsOriginalSource = `false`
	)

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.

Definition at line 779 of file qgsprocessingutils.cpp.

QgsProcessingFeatureSource::~QgsProcessingFeatureSource ( )

override

Definition at line 789 of file qgsprocessingutils.cpp.

Member Function Documentation

QgsFeatureIds QgsProcessingFeatureSource::allFeatureIds ( ) const

overridevirtual

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

Reimplemented from QgsFeatureSource.

Definition at line 878 of file qgsprocessingutils.cpp.

QgsExpressionContextScope * QgsProcessingFeatureSource::createExpressionContextScope ( ) const

Returns an expression context scope suitable for this source.

Definition at line 883 of file qgsprocessingutils.cpp.

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 847 of file qgsprocessingutils.cpp.

QgsFields QgsProcessingFeatureSource::fields ( ) const

overridevirtual

Returns the fields associated with features in the source.

Implements QgsFeatureSource.

Definition at line 837 of file qgsprocessingutils.cpp.

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 795 of file qgsprocessingutils.cpp.

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 823 of file qgsprocessingutils.cpp.

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 811 of file qgsprocessingutils.cpp.

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 868 of file qgsprocessingutils.cpp.

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 863 of file qgsprocessingutils.cpp.

QgsCoordinateReferenceSystem QgsProcessingFeatureSource::sourceCrs ( ) const

overridevirtual

Returns the coordinate reference system for features in the source.

Implements QgsFeatureSource.

Definition at line 832 of file qgsprocessingutils.cpp.

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 873 of file qgsprocessingutils.cpp.

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 852 of file qgsprocessingutils.cpp.

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 858 of file qgsprocessingutils.cpp.

QgsWkbTypes::Type QgsProcessingFeatureSource::wkbType ( ) const

overridevirtual

Returns the geometry type for features returned by this source.

Implements QgsFeatureSource.

Definition at line 842 of file qgsprocessingutils.cpp.

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

/build/qgis-3.4.15+24xenial/src/core/processing/qgsprocessingutils.h
/build/qgis-3.4.15+24xenial/src/core/processing/qgsprocessingutils.cpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation