Contains information about the context in which a processing algorithm is executed. More...

#include <qgsprocessingcontext.h>

Classes
class	LayerDetails
	Details for layers to load into projects. More...

Public Types
enum	Flag
	Flags that affect how processing algorithms are run. More...

Public Member Functions
	QgsProcessingContext ()
	Constructor for QgsProcessingContext. More...

	QgsProcessingContext (const QgsProcessingContext &other)=delete
	QgsProcessingContext cannot be copied. More...

	~QgsProcessingContext ()

void	addLayerToLoadOnCompletion (const QString &layer, const QgsProcessingContext::LayerDetails &details)
	Adds a layer to load (by ID or datasource) into the canvas upon completion of the algorithm or model. More...

void	copyThreadSafeSettings (const QgsProcessingContext &other)
	Copies all settings which are safe for use across different threads from other to this context. More...

QString	defaultEncoding () const
	Returns the default encoding to use for newly created files. More...

QgsExpressionContext &	expressionContext ()
	Returns the expression context. More...

const QgsExpressionContext &	expressionContext () const
	Returns the expression context. More...

QgsProcessingFeedback *	feedback ()
	Returns the associated feedback object. More...

QgsProcessingContext::Flags	flags () const
	Returns any flags set in the context. More...

QgsMapLayer *	getMapLayer (const QString &identifier)
	Returns a map layer from the context with a matching identifier. More...

std::function< void(const QgsFeature &) >	invalidGeometryCallback () const
	Returns the callback function to use when encountering an invalid geometry and invalidGeometryCheck() is set to GeometryAbortOnInvalid. More...

QgsFeatureRequest::InvalidGeometryCheck	invalidGeometryCheck () const
	Returns the behavior used for checking invalid geometries in input layers. More...

QMap< QString, QgsProcessingContext::LayerDetails >	layersToLoadOnCompletion () const
	Returns a map of layers (by ID or datasource) to LayerDetails, to load into the canvas upon completion of the algorithm or model. More...

QgsProcessingContext::LayerDetails &	layerToLoadOnCompletionDetails (const QString &layer)
	Returns a reference to the details for a given layer which is loaded on completion of the algorithm or model. More...

QgsProcessingContext &	operator= (const QgsProcessingContext &other)=delete
	QgsProcessingContext cannot be copied. More...

QString	preferredRasterFormat () const
	Returns the preferred raster format to use for vector outputs. More...

QString	preferredVectorFormat () const
	Returns the preferred vector format to use for vector outputs. More...

QgsProject *	project () const
	Returns the project in which the algorithm is being executed. More...

void	pushToThread (QThread *thread)
	Pushes the thread affinity for the context (including all layers contained in the temporaryLayerStore()) into another thread. More...

void	setDefaultEncoding (const QString &encoding)
	Sets the default encoding to use for newly created files. More...

void	setExpressionContext (const QgsExpressionContext &context)
	Sets the expression context. More...

void	setFeedback (QgsProcessingFeedback *feedback)
	Sets an associated feedback object. More...

void	setFlags (QgsProcessingContext::Flags flags)
	Sets flags for the context. More...

void	setInvalidGeometryCallback (const std::function< void(const QgsFeature &) > &callback)
	Sets a callback function to use when encountering an invalid geometry and invalidGeometryCheck() is set to GeometryAbortOnInvalid. More...

void	setInvalidGeometryCheck (QgsFeatureRequest::InvalidGeometryCheck check)
	Sets the behavior used for checking invalid geometries in input layers. More...

void	setLayersToLoadOnCompletion (const QMap< QString, QgsProcessingContext::LayerDetails > &layers)
	Sets the map of layers (by ID or datasource) to LayerDetails, to load into the canvas upon completion of the algorithm or model. More...

void	setPreferredRasterFormat (const QString &format)
	Sets the preferred raster format to use for vector outputs. More...

void	setPreferredVectorFormat (const QString &format)
	Sets the preferred vector format to use for vector outputs. More...

void	setProject (QgsProject *project)
	Sets the project in which the algorithm will be executed. More...

void	setTransformContext (const QgsCoordinateTransformContext &context)
	Sets the coordinate transform context. More...

void	setTransformErrorCallback (const std::function< void(const QgsFeature &) > &callback)
	Sets a callback function to use when encountering a transform error when iterating features. More...

QgsMapLayer *	takeResultLayer (const QString &id)
	Takes the result map layer with matching id from the context and transfers ownership of it back to the caller. More...

void	takeResultsFrom (QgsProcessingContext &context)
	Takes the results from another context and merges them with the results currently stored in this context. More...

QgsMapLayerStore *	temporaryLayerStore ()
	Returns a reference to the layer store used for storing temporary layers during algorithm execution. More...

QThread *	thread ()
	Returns the thread in which the context lives. More...

QgsCoordinateTransformContext	transformContext () const
	Returns the coordinate transform context. More...

std::function< void(const QgsFeature &) >	transformErrorCallback () const
	Returns the callback function to use when encountering a transform error when iterating features. More...

bool	willLoadLayerOnCompletion (const QString &layer) const
	Returns `true` if the given layer (by ID or datasource) will be loaded into the current project upon completion of the algorithm or model. More...

Detailed Description

Contains information about the context in which a processing algorithm is executed.

Contextual information includes settings such as the associated project, and expression context.

Since: QGIS 3.0

Definition at line 43 of file qgsprocessingcontext.h.

Member Enumeration Documentation

◆ Flag

enum QgsProcessingContext::Flag

Flags that affect how processing algorithms are run.

Definition at line 48 of file qgsprocessingcontext.h.

Constructor & Destructor Documentation

◆ QgsProcessingContext() [1/2]

QgsProcessingContext::QgsProcessingContext ( )

Constructor for QgsProcessingContext.

Definition at line 21 of file qgsprocessingcontext.cpp.

◆ QgsProcessingContext() [2/2]

QgsProcessingContext::QgsProcessingContext ( const QgsProcessingContext & other )

delete

QgsProcessingContext cannot be copied.

◆ ~QgsProcessingContext()

QgsProcessingContext::~QgsProcessingContext ( )

Definition at line 33 of file qgsprocessingcontext.cpp.

Member Function Documentation

◆ addLayerToLoadOnCompletion()

void QgsProcessingContext::addLayerToLoadOnCompletion	(	const QString &	layer,
		const QgsProcessingContext::LayerDetails &	details
	)

Adds a layer to load (by ID or datasource) into the canvas upon completion of the algorithm or model.

The details parameter dictates the LayerDetails.

See also: setLayersToLoadOnCompletion(); layersToLoadOnCompletion(); willLoadLayerOnCompletion(); layerToLoadOnCompletionDetails()

Definition at line 51 of file qgsprocessingcontext.cpp.

◆ copyThreadSafeSettings()

void QgsProcessingContext::copyThreadSafeSettings ( const QgsProcessingContext & other )

inline

Copies all settings which are safe for use across different threads from other to this context.

Definition at line 70 of file qgsprocessingcontext.h.

◆ defaultEncoding()

QString QgsProcessingContext::defaultEncoding ( ) const

inline

Returns the default encoding to use for newly created files.

See also: setDefaultEncoding()

Definition at line 364 of file qgsprocessingcontext.h.

◆ expressionContext() [1/2]

QgsExpressionContext& QgsProcessingContext::expressionContext ( )

inline

Returns the expression context.

Definition at line 119 of file qgsprocessingcontext.h.

◆ expressionContext() [2/2]

const QgsExpressionContext& QgsProcessingContext::expressionContext ( ) const

inline

Returns the expression context.

Definition at line 124 of file qgsprocessingcontext.h.

◆ feedback()

QgsProcessingFeedback* QgsProcessingContext::feedback ( )

inline

Returns the associated feedback object.

See also: setFeedback()

Definition at line 376 of file qgsprocessingcontext.h.

◆ flags()

QgsProcessingContext::Flags QgsProcessingContext::flags ( ) const

inline

Returns any flags set in the context.

See also: setFlags()

Definition at line 87 of file qgsprocessingcontext.h.

◆ getMapLayer()

QgsMapLayer * QgsProcessingContext::getMapLayer ( const QString & identifier )

Returns a map layer from the context with a matching identifier.

This method considers layer IDs, names and sources when matching the identifier (see QgsProcessingUtils::mapLayerFromString() for details).

Ownership is not transferred and remains with the context.

See also: takeResultLayer()

Definition at line 98 of file qgsprocessingcontext.cpp.

◆ invalidGeometryCallback()

std::function< void( const QgsFeature & ) > QgsProcessingContext::invalidGeometryCallback ( ) const

inline

Returns the callback function to use when encountering an invalid geometry and invalidGeometryCheck() is set to GeometryAbortOnInvalid.

Note: not available in Python bindings

See also: setInvalidGeometryCallback()

Since: QGIS 3.0

Definition at line 324 of file qgsprocessingcontext.h.

◆ invalidGeometryCheck()

QgsFeatureRequest::InvalidGeometryCheck QgsProcessingContext::invalidGeometryCheck ( ) const

inline

Returns the behavior used for checking invalid geometries in input layers.

See also: setInvalidGeometryCheck()

Definition at line 282 of file qgsprocessingcontext.h.

◆ layersToLoadOnCompletion()

QMap< QString, QgsProcessingContext::LayerDetails > QgsProcessingContext::layersToLoadOnCompletion ( ) const

inline

Returns a map of layers (by ID or datasource) to LayerDetails, to load into the canvas upon completion of the algorithm or model.

See also: setLayersToLoadOnCompletion(); addLayerToLoadOnCompletion(); willLoadLayerOnCompletion(); layerToLoadOnCompletionDetails()

Definition at line 222 of file qgsprocessingcontext.h.

◆ layerToLoadOnCompletionDetails()

QgsProcessingContext::LayerDetails& QgsProcessingContext::layerToLoadOnCompletionDetails ( const QString & layer )

inline

Returns a reference to the details for a given layer which is loaded on completion of the algorithm or model.

Warning: First check willLoadLayerOnCompletion(), or calling this method will incorrectly add layer as a layer to load on completion.

See also: willLoadLayerOnCompletion(); addLayerToLoadOnCompletion(); setLayersToLoadOnCompletion(); layersToLoadOnCompletion()

Since: QGIS 3.2

Definition at line 273 of file qgsprocessingcontext.h.

◆ operator=()

QgsProcessingContext& QgsProcessingContext::operator= ( const QgsProcessingContext & other )

delete

QgsProcessingContext cannot be copied.

◆ preferredRasterFormat()

QString QgsProcessingContext::preferredRasterFormat ( ) const

inline

Returns the preferred raster format to use for vector outputs.

This method returns a file extension to use when creating raster outputs (e.g. "tif"). Generally, it is preferable to use the extension associated with a particular parameter, which can be retrieved through QgsProcessingDestinationParameter::defaultFileExtension(). However, in some cases, a specific parameter may not be available to call this method on (e.g. for an algorithm which has only an output folder parameter and which creates multiple output layers in that folder). In this case, the format returned by this function should be used when creating these outputs.

It is the algorithm's responsibility to check whether the returned format is acceptable for the algorithm, and to provide an appropriate fallback when the returned format is not usable.

See also: setPreferredRasterFormat(); preferredVectorFormat()

Since: QGIS 3.10

Definition at line 492 of file qgsprocessingcontext.h.

◆ preferredVectorFormat()

QString QgsProcessingContext::preferredVectorFormat ( ) const

inline

Returns the preferred vector format to use for vector outputs.

This method returns a file extension to use when creating vector outputs (e.g. "shp"). Generally, it is preferable to use the extension associated with a particular parameter, which can be retrieved through QgsProcessingDestinationParameter::defaultFileExtension(). However, in some cases, a specific parameter may not be available to call this method on (e.g. for an algorithm which has only an output folder parameter and which creates multiple output layers in that folder). In this case, the format returned by this function should be used when creating these outputs.

It is the algorithm's responsibility to check whether the returned format is acceptable for the algorithm, and to provide an appropriate fallback when the returned format is not usable.

See also: setPreferredVectorFormat(); preferredRasterFormat()

Since: QGIS 3.10

Definition at line 455 of file qgsprocessingcontext.h.

◆ project()

QgsProject* QgsProcessingContext::project ( ) const

inline

Returns the project in which the algorithm is being executed.

See also: setProject()

Definition at line 99 of file qgsprocessingcontext.h.

◆ pushToThread()

void QgsProcessingContext::pushToThread ( QThread * thread )

inline

Pushes the thread affinity for the context (including all layers contained in the temporaryLayerStore()) into another thread.

This method is only safe to call when the current thread matches the existing thread affinity for the context (see thread()).

See also: thread()

Definition at line 400 of file qgsprocessingcontext.h.

◆ setDefaultEncoding()

void QgsProcessingContext::setDefaultEncoding ( const QString & encoding )

inline

Sets the default encoding to use for newly created files.

See also: defaultEncoding()

Definition at line 370 of file qgsprocessingcontext.h.

◆ setExpressionContext()

void QgsProcessingContext::setExpressionContext ( const QgsExpressionContext & context )

inline

Sets the expression context.

Definition at line 129 of file qgsprocessingcontext.h.

◆ setFeedback()

void QgsProcessingContext::setFeedback ( QgsProcessingFeedback * feedback )

inline

Sets an associated feedback object.

This allows context related functions to report feedback and errors to users and processing logs. While ideally this feedback object should outlive the context, only a weak pointer to feedback is stored and no errors will occur if feedback is deleted before the context. Ownership of feedback is not transferred.

See also: setFeedback()

Definition at line 386 of file qgsprocessingcontext.h.

◆ setFlags()

void QgsProcessingContext::setFlags ( QgsProcessingContext::Flags flags )

inline

Sets flags for the context.

See also: flags()

Definition at line 93 of file qgsprocessingcontext.h.

◆ setInvalidGeometryCallback()

void QgsProcessingContext::setInvalidGeometryCallback ( const std::function< void(const QgsFeature &) > & callback )

inline

Sets a callback function to use when encountering an invalid geometry and invalidGeometryCheck() is set to GeometryAbortOnInvalid.

This function will be called using the feature with invalid geometry as a parameter.

See also: invalidGeometryCallback()

Since: QGIS 3.0

Definition at line 300 of file qgsprocessingcontext.h.

◆ setInvalidGeometryCheck()

void QgsProcessingContext::setInvalidGeometryCheck ( QgsFeatureRequest::InvalidGeometryCheck check )

Sets the behavior used for checking invalid geometries in input layers.

Settings this to anything but QgsFeatureRequest::GeometryNoCheck will also reset the invalidGeometryCallback() to a default implementation.

See also: invalidGeometryCheck()

Definition at line 59 of file qgsprocessingcontext.cpp.

◆ setLayersToLoadOnCompletion()

void QgsProcessingContext::setLayersToLoadOnCompletion ( const QMap< QString, QgsProcessingContext::LayerDetails > & layers )

Sets the map of layers (by ID or datasource) to LayerDetails, to load into the canvas upon completion of the algorithm or model.

See also: addLayerToLoadOnCompletion(); layersToLoadOnCompletion(); willLoadLayerOnCompletion(); layerToLoadOnCompletionDetails()

Definition at line 41 of file qgsprocessingcontext.cpp.

◆ setPreferredRasterFormat()

void QgsProcessingContext::setPreferredRasterFormat ( const QString & format )

inline

Sets the preferred raster format to use for vector outputs.

This method sets a file extension to use when creating raster outputs (e.g. "tif"). Generally, it is preferable to use the extension associated with a particular parameter, which can be retrieved through QgsProcessingDestinationParameter::defaultFileExtension(). However, in some cases, a specific parameter may not be available to call this method on (e.g. for an algorithm which has only an output folder parameter and which creates multiple output layers in that folder). In this case, the format set by this function will be used when creating these outputs.

See also: preferredRasterFormat(); setPreferredVectorFormat()

Since: QGIS 3.10

Definition at line 509 of file qgsprocessingcontext.h.

◆ setPreferredVectorFormat()

void QgsProcessingContext::setPreferredVectorFormat ( const QString & format )

inline

Sets the preferred vector format to use for vector outputs.

This method sets a file extension to use when creating vector outputs (e.g. "shp"). Generally, it is preferable to use the extension associated with a particular parameter, which can be retrieved through QgsProcessingDestinationParameter::defaultFileExtension(). However, in some cases, a specific parameter may not be available to call this method on (e.g. for an algorithm which has only an output folder parameter and which creates multiple output layers in that folder). In this case, the format set by this function will be used when creating these outputs.

See also: preferredVectorFormat(); setPreferredRasterFormat()

Since: QGIS 3.10

Definition at line 472 of file qgsprocessingcontext.h.

◆ setProject()

void QgsProcessingContext::setProject ( QgsProject * project )

inline

Sets the project in which the algorithm will be executed.

This also automatically sets the transformContext() to match the project's transform context.

See also: project()

Definition at line 109 of file qgsprocessingcontext.h.

◆ setTransformContext()

void QgsProcessingContext::setTransformContext ( const QgsCoordinateTransformContext & context )

inline

Sets the coordinate transform context.

Note that setting a project for the context will automatically set the coordinate transform context.

See also: transformContext()

Definition at line 145 of file qgsprocessingcontext.h.

◆ setTransformErrorCallback()

void QgsProcessingContext::setTransformErrorCallback ( const std::function< void(const QgsFeature &) > & callback )

inline

Sets a callback function to use when encountering a transform error when iterating features.

This function will be called using the feature which encountered the transform error as a parameter.

See also: transformErrorCallback()

Since: QGIS 3.0

Definition at line 334 of file qgsprocessingcontext.h.

◆ takeResultLayer()

QgsMapLayer * QgsProcessingContext::takeResultLayer ( const QString & id )

Takes the result map layer with matching id from the context and transfers ownership of it back to the caller.

This method can be used to remove temporary layers which are not required for further processing from a context.

See also: getMapLayer()

Definition at line 103 of file qgsprocessingcontext.cpp.

◆ takeResultsFrom()

void QgsProcessingContext::takeResultsFrom ( QgsProcessingContext & context )

Takes the results from another context and merges them with the results currently stored in this context.

This includes settings like any layers loaded in the temporaryLayerStore() and layersToLoadOnCompletion(). This is only safe to call when both this context and the other context share the same thread() affinity, and that thread is the current thread.

Definition at line 91 of file qgsprocessingcontext.cpp.

◆ temporaryLayerStore()

QgsMapLayerStore* QgsProcessingContext::temporaryLayerStore ( )

inline

Returns a reference to the layer store used for storing temporary layers during algorithm execution.

Definition at line 151 of file qgsprocessingcontext.h.

◆ thread()

QThread* QgsProcessingContext::thread ( )

inline

Returns the thread in which the context lives.

See also: pushToThread()

Definition at line 392 of file qgsprocessingcontext.h.

◆ transformContext()

QgsCoordinateTransformContext QgsProcessingContext::transformContext ( ) const

inline

Returns the coordinate transform context.

See also: setTransformContext()

Definition at line 135 of file qgsprocessingcontext.h.

◆ transformErrorCallback()

std::function< void( const QgsFeature & ) > QgsProcessingContext::transformErrorCallback ( ) const

inline

Returns the callback function to use when encountering a transform error when iterating features.

Note: not available in Python bindings

See also: setTransformErrorCallback()

Since: QGIS 3.0

Definition at line 358 of file qgsprocessingcontext.h.

◆ willLoadLayerOnCompletion()

bool QgsProcessingContext::willLoadLayerOnCompletion ( const QString & layer ) const

inline

Returns true if the given layer (by ID or datasource) will be loaded into the current project upon completion of the algorithm or model.

See also: layersToLoadOnCompletion(); setLayersToLoadOnCompletion(); addLayerToLoadOnCompletion(); layerToLoadOnCompletionDetails()

Since: QGIS 3.2

Definition at line 236 of file qgsprocessingcontext.h.

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

/build/qgis-3.10.0+15buster/src/core/processing/qgsprocessingcontext.h
/build/qgis-3.10.0+15buster/src/core/processing/qgsprocessingcontext.cpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ Flag

Constructor & Destructor Documentation

◆ QgsProcessingContext() [1/2]

◆ QgsProcessingContext() [2/2]

◆ ~QgsProcessingContext()

Member Function Documentation

◆ addLayerToLoadOnCompletion()

◆ copyThreadSafeSettings()

◆ defaultEncoding()

◆ expressionContext() [1/2]

◆ expressionContext() [2/2]

◆ feedback()

◆ flags()

◆ getMapLayer()

◆ invalidGeometryCallback()

◆ invalidGeometryCheck()

◆ layersToLoadOnCompletion()

◆ layerToLoadOnCompletionDetails()

◆ operator=()

◆ preferredRasterFormat()

◆ preferredVectorFormat()

◆ project()

◆ pushToThread()

◆ setDefaultEncoding()

◆ setExpressionContext()

◆ setFeedback()

◆ setFlags()

◆ setInvalidGeometryCallback()

◆ setInvalidGeometryCheck()

◆ setLayersToLoadOnCompletion()

◆ setPreferredRasterFormat()

◆ setPreferredVectorFormat()

◆ setProject()

◆ setTransformContext()

◆ setTransformErrorCallback()

◆ takeResultLayer()

◆ takeResultsFrom()

◆ temporaryLayerStore()

◆ thread()

◆ transformContext()

◆ transformErrorCallback()

◆ willLoadLayerOnCompletion()