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qgsfeaturerequest.h
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qgsfeaturerequest.h
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/***************************************************************************
qgsfeaturerequest.h
---------------------
begin : Mai 2012
copyright : (C) 2012 by Martin Dobias
email : wonder dot sk at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef QGSFEATUREREQUEST_H
#define QGSFEATUREREQUEST_H
#include "qgis_core.h"
#include "qgis_sip.h"
#include <QFlags>
#include <QList>
#include <memory>
#include "qgis.h"
#include "qgsfeature.h"
#include "qgsrectangle.h"
#include "qgsexpression.h"
#include "qgsexpressioncontext.h"
#include "qgssimplifymethod.h"
#include "qgscoordinatetransformcontext.h"
#include "qgscoordinatereferencesystem.h"
/**
* \ingroup core
* \brief This class wraps a request for features to a vector layer (or directly its vector data provider).
*
* The request may apply an attribute/ID filter to fetch only a particular subset of features. Currently supported filters:
*
* - no filter - all features are returned
* - feature id - only feature that matches given feature id is returned
* - feature ids - only features that match any of the given feature ids are returned
* - filter expression - only features that match the given filter expression are returned
*
* Additionally a spatial filter can be set in combination with the attribute/ID filter. Supported
* spatial filters are:
*
* - Qgis::SpatialFilterType::BoundingBox: Only features that intersect a given rectangle will be fetched. For the sake of speed, the intersection is often done only using feature's bounding box. There is a flag ExactIntersect that makes sure that only intersecting features will be returned.
* - Qgis::SpatialFilterType::DistanceWithin: Only features within a specified distance of a reference geometry will be fetched.
*
* For efficiency, it is also possible to tell provider that some data is not required:
*
* - NoGeometry flag
* - SubsetOfAttributes flag
* - SimplifyMethod for geometries to fetch
*
* The options may be chained, e.g.:
*
* \code{.py}
* QgsFeatureRequest().setFilterRect(QgsRectangle(0,0,1,1)).setFlags(QgsFeatureRequest.ExactIntersect)
* \endcode
*
* Examples:
*
* \code{.py}
* # fetch all features:
* QgsFeatureRequest()
* # fetch all features, only one attribute
* QgsFeatureRequest().setSubsetOfAttributes(['myfield'], layer.fields())
* # fetch all features, without geometries
* QgsFeatureRequest().setFlags(QgsFeatureRequest.NoGeometry)
* # fetch only features from particular extent
* QgsFeatureRequest().setFilterRect(QgsRectangle(0,0,1,1))
* # fetch only features from particular extent, where the 'type' attribute is equal to 'road':
* QgsFeatureRequest().setFilterRect(QgsRectangle(0,0,1,1)).setFilterExpression('"type"=\'road\'')
* # fetch only one feature
* QgsFeatureRequest().setFilterFid(45)
* # fetch features within 50 map units of a linestring geometry
* QgsFeatureRequest().setDistanceWithin(QgsGeometry.fromWkt('LineString(0 0, 10 0, 12 1)'), 50)
* \endcode
*
*/
class CORE_EXPORT QgsFeatureRequest
{
public:
/**
* \ingroup core
* \brief The OrderByClause class represents an order by clause for a QgsFeatureRequest.
*
* It can be a simple field or an expression. Multiple order by clauses can be added to
* a QgsFeatureRequest to fine tune the behavior if a single field or expression is not
* enough to completely specify the required behavior.
*
* If expression compilation is activated in the settings and the expression can be
* translated for the provider in question, it will be evaluated on provider side.
* If one of these two premises does not apply, the ordering will take place locally
* which results in increased memory and CPU usage.
*
* If the ordering is done on strings, the order depends on the system's locale if the
* local fallback implementation is used. The order depends on the server system's locale
* and implementation if ordering is done on the server.
*
* In case the fallback code needs to be used, a limit set on the request will be respected
* for the features returned by the iterator but internally all features will be requested
* from the provider.
*
*/
class CORE_EXPORT OrderByClause
{
public:
/**
* Creates a new OrderByClause for a QgsFeatureRequest
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* If the order is ascending, by default nulls are last
* If the order is descending, by default nulls are first
*/
OrderByClause( const QString &expression, bool ascending = true );
/**
* Creates a new OrderByClause for a QgsFeatureRequest
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* \param nullsfirst If TRUE, NULLS are at the beginning, if FALSE, NULLS are at the end
*/
OrderByClause( const QString &expression, bool ascending, bool nullsfirst );
/**
* Creates a new OrderByClause for a QgsFeatureRequest
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* If the order is ascending, by default nulls are last
* If the order is descending, by default nulls are first
*/
OrderByClause( const QgsExpression &expression, bool ascending = true );
/**
* Creates a new OrderByClause for a QgsFeatureRequest
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* \param nullsfirst If TRUE, NULLS are at the beginning, if FALSE, NULLS are at the end
*/
OrderByClause( const QgsExpression &expression, bool ascending, bool nullsfirst );
/**
* The expression
* \returns the expression
*/
QgsExpression expression() const;
/**
* Prepare the expression with the given context.
*
* \see QgsExpression::prepare
*
*/
bool prepare( QgsExpressionContext *context );
/**
* Order ascending
* \returns If ascending order is requested
*/
bool ascending() const;
/**
* Set if ascending order is requested
*/
void setAscending( bool ascending );
/**
* Set if NULLS should be returned first
* \returns if NULLS should be returned first
*/
bool nullsFirst() const;
/**
* Set if NULLS should be returned first
*/
void setNullsFirst( bool nullsFirst );
/**
* Dumps the content to an SQL equivalent
*/
QString dump() const;
// friend inline int qHash(const OrderByClause &a) { return qHash(a.mExpression.expression()) ^ qHash(a.mAscending) ^ qHash( a.mNullsFirst); }
bool operator==( const OrderByClause &v ) const
{
return mExpression == v.mExpression &&
mAscending == v.mAscending &&
mNullsFirst == v.mNullsFirst;
}
bool operator!=( const OrderByClause &v ) const
{
return !( v == *this );
}
private:
QgsExpression mExpression;
bool mAscending;
bool mNullsFirst;
};
/**
* \ingroup core
* \brief Represents a list of OrderByClauses, with the most important first and the least
* important last.
*
*/
class OrderBy : public QList<QgsFeatureRequest::OrderByClause>
{
public:
/**
* Create a new empty order by
*/
CORE_EXPORT OrderBy();
/**
* Create a new order by from a list of clauses
*/
CORE_EXPORT OrderBy( const QList<QgsFeatureRequest::OrderByClause> &other );
/**
* Equality operator
* \since QGIS 3.38
*/
CORE_EXPORT bool operator==( const OrderBy &v ) const;
/**
* Inequality operator
* \since QGIS 3.38
*/
CORE_EXPORT bool operator!=( const OrderBy &v ) const;
/**
* Gets a copy as a list of OrderByClauses
*
* This is only required in Python where the inheritance
* is not properly propagated and this makes it usable.
*/
QList<QgsFeatureRequest::OrderByClause> CORE_EXPORT list() const;
/**
* Serialize to XML
*/
void CORE_EXPORT save( QDomElement &elem ) const;
/**
* Deserialize from XML
*/
void CORE_EXPORT load( const QDomElement &elem );
/**
* Returns a set of used attributes
* \note The returned attributes names are NOT guaranteed to be valid.
*/
QSet<QString> CORE_EXPORT usedAttributes() const;
/**
* Returns a set of used, validated attribute indices
* \since QGIS 3.8
*/
QSet<int> CORE_EXPORT usedAttributeIndices( const QgsFields &fields ) const;
/**
* Dumps the content to an SQL equivalent syntax
*/
QString CORE_EXPORT dump() const;
};
/**
* A special attribute that if set matches all attributes
*/
static const QString ALL_ATTRIBUTES;
//! construct a default request: for all features get attributes and geometries
QgsFeatureRequest();
//! construct a request with feature ID filter
explicit QgsFeatureRequest( QgsFeatureId fid );
//! construct a request with feature ID filter
explicit QgsFeatureRequest( const QgsFeatureIds &fids );
/**
* Construct a request with \a rectangle bounding box filter.
*
* When a destination CRS is set using setDestinationCrs(), \a rectangle
* is expected to be in the same CRS as the destinationCrs(). Otherwise, \a rectangle
* should use the same CRS as the source layer/provider.
*/
explicit QgsFeatureRequest( const QgsRectangle &rectangle );
//! construct a request with a filter expression
explicit QgsFeatureRequest( const QgsExpression &expr, const QgsExpressionContext &context = QgsExpressionContext() );
//! copy constructor
QgsFeatureRequest( const QgsFeatureRequest &rh );
//! Assignment operator
QgsFeatureRequest &operator=( const QgsFeatureRequest &rh );
/**
* Compare two requests for equality, ignoring Expression Context, Transform Error Callback, Feedback and Invalid Geometry Callback
* \param other the other request
* \return TRUE if the requests are equal in all respects but without checking for Expression Context, Transform Error, Feedback and Invalid Geometry Callback
* \since QGIS 3.38
*/
bool compare( const QgsFeatureRequest &other ) const;
~QgsFeatureRequest();
/**
* Returns the attribute/ID filter type which is currently set on this request.
*
* This type will automatically be set to the appropriate value whenever setFilterFid(),
* setFilterFids(), setFilterExpression() or disableFilter() are called.
*
* \note A feature request may have both an attribute/ID filter AND a spatial filter
* set. See spatialFilterType() to retrieve the spatial filter.
*
* \see spatialFilterType()
*/
Qgis::FeatureRequestFilterType filterType() const { return mFilter; }
/**
* Returns the spatial filter type which is currently set on this request.
*
* This type will automatically be set to the appropriate value whenever setFilterRect(),
* or setDistanceWithin() are called.
*
* \note A feature request may have both an attribute/ID filter AND a spatial filter
* set. See filterType() to retrieve the attribute/ID filter.
*
* \see filterType()
* \since QGIS 3.22
*/
Qgis::SpatialFilterType spatialFilterType() const { return mSpatialFilter; }
/**
* Sets the \a rectangle from which features will be taken. An empty rectangle removes the filter.
*
* When a destination CRS is set using setDestinationCrs(), \a rectangle
* is expected to be in the same CRS as the destinationCrs(). Otherwise, \a rectangle
* should use the same CRS as the source layer/provider.
*
* Calling this method will automatically set spatialFilterType() to Qgis::SpatialFilterType::BoundingBox.
* If \a rectangle is a null rectangle then spatialFilterType() will be reset to Qgis::SpatialFilterType::NoFilter.
*
* \see filterRect()
*/
QgsFeatureRequest &setFilterRect( const QgsRectangle &rectangle );
/**
* Returns the rectangle from which features will be taken. If the returned
* rectangle is null, then no filter rectangle is set.
*
* If spatialFilterType() is Qgis::SpatialFilterType::BoundingBox then only
* features from within this bounding box will be fetched. If spatialFilterType()
* is Qgis::SpatialFilterType::DistanceWithin then the returned rectangle
* represents the bounding box of the referenceGeometry() extended by distanceWithin().
*
* When a destination CRS is set using setDestinationCrs(), the rectangle
* will be in the same CRS as the destinationCrs(). Otherwise, the rectangle
* will use the same CRS as the source layer/provider.
*
* \see setFilterRect()
*/
QgsRectangle filterRect() const;
/**
* Sets a reference \a geometry and a maximum \a distance from this geometry to retrieve
* features within.
*
* When a destination CRS is set using setDestinationCrs(), \a geometry
* is expected to be in the same CRS as the destinationCrs() and \a distance is in
* the spatial units of the destinationCrs(). Otherwise, \a geometry
* should use the same CRS as the source layer/provider and \a distance
* should use the spatial units as this same CRS.
*
* Calling this method will automatically set spatialFilterType() to Qgis::SpatialFilterType::DistanceWithin.
*
* \see filterRect()
* \since QGIS 3.22
*/
QgsFeatureRequest &setDistanceWithin( const QgsGeometry &geometry, double distance );
/**
* Returns the reference geometry used for spatial filtering of features.
*
* When spatialFilterType() is Qgis::SpatialFilterType::DistanceWithin then only
* features within distanceWithin() units of the reference geometry will be
* fetched.
*
* When a destination CRS is set using setDestinationCrs(), the geometry
* will be in the same CRS as the destinationCrs(). Otherwise, the geometry
* will use the same CRS as the source layer/provider.
*
* \see setDistanceWithin()
* \since QGIS 3.22
*/
QgsGeometry referenceGeometry() const { return mReferenceGeometry; }
/**
* Returns the reference geometry engine used for spatial filtering of features.
*
* This is to avoid re-creating the engine.
*
* \see referenceGeometry()
* \since QGIS 3.22
*/
std::shared_ptr< QgsGeometryEngine > referenceGeometryEngine() const SIP_SKIP { return mReferenceGeometryEngine; }
/**
* Returns the maximum distance from the referenceGeometry() of fetched
* features, if spatialFilterType() is Qgis::SpatialFilterType::DistanceWithin.
*
* When a destination CRS is set using setDestinationCrs(), the distance
* will be in the spatial units of destinationCrs(). Otherwise, the distance
* will use the same units as the CRS of the source layer/provider.
*
* \see setDistanceWithin()
* \since QGIS 3.22
*/
double distanceWithin() const { return mDistanceWithin; }
/**
* Sets the feature ID that should be fetched.
*
* Calling this method will automatically set filterType() to QgsFeatureRequest::FilterFid.
*
* \see filterFid()
* \see setFilterFids()
*/
QgsFeatureRequest &setFilterFid( QgsFeatureId fid );
/**
* Returns the feature ID that should be fetched.
*
* \see setFilterFid()
* \see filterFids()
*/
QgsFeatureId filterFid() const { return mFilterFid; }
/**
* Sets the feature IDs that should be fetched.
*
* Calling this method will automatically set filterType() to QgsFeatureRequest::FilterFids.
*
* \see filterFids()
* \see setFilterFid()
*/
QgsFeatureRequest &setFilterFids( const QgsFeatureIds &fids );
/**
* Returns the feature IDs that should be fetched.
*
* \see setFilterFids()
* \see filterFid()
*/
const QgsFeatureIds &filterFids() const { return mFilterFids; }
/**
* Sets invalid geometry checking behavior.
* \note Invalid geometry checking is not performed when retrieving features
* directly from a QgsVectorDataProvider.
* \see invalidGeometryCheck()
*/
QgsFeatureRequest &setInvalidGeometryCheck( Qgis::InvalidGeometryCheck check );
/**
* Returns the invalid geometry checking behavior.
* \see setInvalidGeometryCheck()
*/
Qgis::InvalidGeometryCheck invalidGeometryCheck() const { return mInvalidGeometryFilter; }
/**
* Sets a callback function to use when encountering an invalid geometry and
* invalidGeometryCheck() is set to GeometryAbortOnInvalid or GeometrySkipInvalid. This function will be
* called using the feature with invalid geometry as a parameter.
* \see invalidGeometryCallback()
*/
#ifndef SIP_RUN
QgsFeatureRequest &setInvalidGeometryCallback( const std::function< void( const QgsFeature & )> &callback );
#else
QgsFeatureRequest &setInvalidGeometryCallback( SIP_PYCALLABLE / AllowNone / );
% MethodCode
Py_BEGIN_ALLOW_THREADS
sipCpp->setInvalidGeometryCallback( [a0]( const QgsFeature &arg )
{
SIP_BLOCK_THREADS
Py_XDECREF( sipCallMethod( NULL, a0, "D", &arg, sipType_QgsFeature, NULL ) );
SIP_UNBLOCK_THREADS
} );
sipRes = sipCpp;
Py_END_ALLOW_THREADS
% End
#endif
/**
* Returns the callback function to use when encountering an invalid geometry and
* invalidGeometryCheck() is set to GeometryAbortOnInvalid or GeometrySkipInvalid.
* \note not available in Python bindings
* \see setInvalidGeometryCallback()
*/
std::function< void( const QgsFeature & ) > invalidGeometryCallback() const { return mInvalidGeometryCallback; } SIP_SKIP
/**
* Set the filter \a expression. {\see QgsExpression}
* \param expression expression string
*
* Calling this method will automatically set filterType() to QgsFeatureRequest::FilterExpression.
*
* \see filterExpression()
* \see setExpressionContext()
*/
QgsFeatureRequest &setFilterExpression( const QString &expression );
/**
* Returns the filter expression (if set).
* \see setFilterExpression()
* \see expressionContext()
*/
QgsExpression *filterExpression() const { return mFilterExpression.get(); }
/**
* Modifies the existing filter expression to add an additional expression filter. The
* filter expressions are combined using AND, so only features matching both
* the existing expression and the additional expression will be returned.
*
* Calling this method will automatically set filterType() to QgsFeatureRequest::FilterExpression.
*
*/
QgsFeatureRequest &combineFilterExpression( const QString &expression );
/**
* Returns the expression context used to evaluate filter expressions.
* \see setExpressionContext
* \see filterExpression
*/
QgsExpressionContext *expressionContext() { return &mExpressionContext; }
/**
* Sets the expression context used to evaluate filter expressions.
* \see expressionContext
* \see setFilterExpression
*/
QgsFeatureRequest &setExpressionContext( const QgsExpressionContext &context );
/**
* Disables any attribute/ID filtering.
*
* Calling this method will automatically set filterType() to QgsFeatureRequest::FilterNone.
*
* \note Spatial filters will be left in place.
*
* \returns The object the method is called on for chaining
*
*/
QgsFeatureRequest &disableFilter() { mFilter = Qgis::FeatureRequestFilterType::NoFilter; mFilterExpression.reset(); return *this; }
/**
* Adds a new OrderByClause, appending it as the least important one.
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* If the order is ascending, by default nulls are last
* If the order is descending, by default nulls are first
*
*/
QgsFeatureRequest &addOrderBy( const QString &expression, bool ascending = true );
/**
* Adds a new OrderByClause, appending it as the least important one.
*
* \param expression The expression to use for ordering
* \param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
* \param nullsfirst If TRUE, NULLS are at the beginning, if FALSE, NULLS are at the end
*
*/
QgsFeatureRequest &addOrderBy( const QString &expression, bool ascending, bool nullsfirst );
/**
* Returns a list of order by clauses specified for this feature request.
*
*/
OrderBy orderBy() const;
/**
* Set a list of order by clauses.
*
*/
QgsFeatureRequest &setOrderBy( const OrderBy &orderBy );
/**
* Set the maximum number of features to request.
* \param limit maximum number of features, or -1 to request all features.
* \see limit()
*/
QgsFeatureRequest &setLimit( long long limit );
/**
* Returns the maximum number of features to request, or -1 if no limit set.
* \see setLimit
*/
#ifndef SIP_RUN
long long limit() const { return mLimit; }
#else
long long limit() const;
#endif
/**
* Sets \a flags that affect how features will be fetched.
*
* \see flags()
*/
QgsFeatureRequest &setFlags( Qgis::FeatureRequestFlags flags );
/**
* Returns the flags which affect how features are fetched.
*
* \see setFlags()
*/
Qgis::FeatureRequestFlags flags() const { return mFlags; }
/**
* Set a subset of attributes that will be fetched.
*
* An empty attributes list indicates that no attributes will be fetched.
* To revert a call to setSubsetOfAttributes and fetch all available attributes,
* the SubsetOfAttributes flag should be removed from the request.
*
* \note This is intended as hint to data providers for optimising feature retrieval. Depending
* on the provider, it may be trivial for the provider to always return all attributes instead of
* the requested subset, or actually result in slower retrieval when the attributes are filtered out.
* In these cases the provider may ignore this hint and return all attributes regardless of the
* requested attributes.
*
* \see subsetOfAttributes()
* \see setNoAttributes()
*/
QgsFeatureRequest &setSubsetOfAttributes( const QgsAttributeList &attrs );
/**
* Set that no attributes will be fetched.
*
* To revert a call to setNoAttributes and fetch all or some available attributes,
* the SubsetOfAttributes flag should be removed from the request.
*
* \note This is intended as hint to data providers for optimising feature retrieval. Depending
* on the provider, it may be trivial for the provider to always return all attributes instead of
* removing them. In these cases the provider may ignore this hint and return all attributes
* regardless of whether this method has been called.
*
* \see setSubsetOfAttributes()
*
* \since QGIS 3.4
*/
QgsFeatureRequest &setNoAttributes();
/**
* Returns the subset of attributes which at least need to be fetched.
* \returns A list of attributes to be fetched
*
* \note This is intended as hint to data providers for optimising feature retrieval. Depending
* on the provider, it may be trivial for the provider to always return all attributes instead of
* the requested subset, or actually result in slower retrieval when the attributes are filtered out.
* In these cases the provider may ignore this hint and return all attributes regardless of the
* requested attributes.
*
* \see setSubsetOfAttributes()
* \see setNoAttributes()
*/
QgsAttributeList subsetOfAttributes() const { return mAttrs; }
/**
* Sets a subset of attributes by names that will be fetched.
*
* \note This is intended as hint to data providers for optimising feature retrieval. Depending
* on the provider, it may be trivial for the provider to always return all attributes instead of
* the requested subset, or actually result in slower retrieval when the attributes are filtered out.
* In these cases the provider may ignore this hint and return all attributes regardless of the
* requested attributes.
*
* \see subsetOfAttributes()
*/
QgsFeatureRequest &setSubsetOfAttributes( const QStringList &attrNames, const QgsFields &fields );
/**
* Sets a subset of attributes by names that will be fetched.
*
* \note This is intended as hint to data providers for optimising feature retrieval. Depending
* on the provider, it may be trivial for the provider to always return all attributes instead of
* the requested subset, or actually result in slower retrieval when the attributes are filtered out.
* In these cases the provider may ignore this hint and return all attributes regardless of the
* requested attributes.
*
* \see subsetOfAttributes()
*/
QgsFeatureRequest &setSubsetOfAttributes( const QSet<QString> &attrNames, const QgsFields &fields );
/**
* Set a simplification method for geometries that will be fetched.
*
* \see simplifyMethod()
*/
QgsFeatureRequest &setSimplifyMethod( const QgsSimplifyMethod &simplifyMethod );
/**
* Returns the simplification method for geometries that will be fetched.
*
* \see setSimplifyMethod()
*/
const QgsSimplifyMethod &simplifyMethod() const { return mSimplifyMethod; }
/**
* Returns the destination coordinate reference system for feature's geometries,
* or an invalid QgsCoordinateReferenceSystem if no reprojection will be done
* and all features will be left with their original geometry.
* \see setDestinationCrs()
* \see transformContext()
*/
QgsCoordinateReferenceSystem destinationCrs() const;
/**
* Returns the transform context, for use when a destinationCrs() has been set
* and reprojection is required
* \see setDestinationCrs()
* \see destinationCrs()
*/
QgsCoordinateTransformContext transformContext() const;
/**
* Sets the destination \a crs for feature's geometries. If set, all
* geometries will be reprojected from their original coordinate reference
* system to this desired reference system. If \a crs is an invalid
* QgsCoordinateReferenceSystem then no reprojection will be done
* and all features will be left with their original geometry.
*
* When a \a crs is set using setDestinationCrs(), then any filterRect()
* or referenceGeometry() set on the request is expected to be in the
* same CRS as the destination CRS.
*
* The feature geometry transformation to the destination CRS is performed
* after all filter expressions are tested and any virtual fields are
* calculated. Accordingly, any geometric expressions used in
* filterExpression() will be performed in the original
* source CRS. This ensures consistent results are returned regardless of the
* destination CRS. Similarly, virtual field values will be calculated using the
* original geometry in the source CRS, so these values are not affected by
* any destination CRS transform present in the feature request.
*
* \see destinationCrs()
*/
QgsFeatureRequest &setDestinationCrs( const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context );
/**
* Sets a callback function to use when encountering a transform error when iterating
* features and a destinationCrs() is set. This function will be
* called using the feature which encountered the transform error as a parameter.
* \see transformErrorCallback()
* \see setDestinationCrs()
*/
#ifndef SIP_RUN
QgsFeatureRequest &setTransformErrorCallback( const std::function< void( const QgsFeature & )> &callback );
#else
QgsFeatureRequest &setTransformErrorCallback( SIP_PYCALLABLE / AllowNone / );
% MethodCode
Py_BEGIN_ALLOW_THREADS
sipCpp->setTransformErrorCallback( [a0]( const QgsFeature &arg )
{
SIP_BLOCK_THREADS
Py_XDECREF( sipCallMethod( NULL, a0, "D", &arg, sipType_QgsFeature, NULL ) );
SIP_UNBLOCK_THREADS
} );
sipRes = sipCpp;
Py_END_ALLOW_THREADS
% End
#endif
/**
* Returns the callback function to use when encountering a transform error when iterating
* features and a destinationCrs() is set.
* \note not available in Python bindings
* \see setTransformErrorCallback()
* \see destinationCrs()
*/
std::function< void( const QgsFeature & ) > transformErrorCallback() const { return mTransformErrorCallback; } SIP_SKIP
/**
* Check if a feature is accepted by this requests filter
*
* \param feature The feature which will be tested
*
* \returns TRUE, if the filter accepts the feature
*
*/
bool acceptFeature( const QgsFeature &feature );
/**
* Returns the timeout (in milliseconds) for how long we should wait for a connection if none is available from the pool
* at this moment. A negative value (which is set by default) will wait forever.
*
* \note Only works if the provider supports this option.
*
* \deprecated Use timeout() instead.
*/
Q_DECL_DEPRECATED int connectionTimeout() const SIP_DEPRECATED;
/**
* Sets the timeout (in milliseconds) for how long we should wait for a connection if none is available from the pool
* at this moment. A negative value (which is set by default) will wait forever.
*
* \note Only works if the provider supports this option.
*
* \deprecated Use setTimeout() instead.
*/
Q_DECL_DEPRECATED QgsFeatureRequest &setConnectionTimeout( int connectionTimeout ) SIP_DEPRECATED;
/**
* Returns the timeout (in milliseconds) for the maximum time we should wait during feature requests before a
* feature is returned. A negative value (which is set by default) will wait forever.
*
* \note Only works if the provider supports this option.
*
* \see setTimeout()
* \since QGIS 3.4
*/
int timeout() const;
/**
* Sets the \a timeout (in milliseconds) for the maximum time we should wait during feature requests before a
* feature is returned. A negative value (which is set by default) will wait forever.
*
* \note Only works if the provider supports this option.
*
* \see timeout()
* \since QGIS 3.4
*/
QgsFeatureRequest &setTimeout( int timeout );
/**
* In case this request may be run nested within another already running
* iteration on the same connection, set this to TRUE.
*
* If this flag is TRUE, this request will be able to make use of "spare"
* connections to avoid deadlocks.
*
* For example, this should be set on requests that are issued from an
* expression function.
*
* \see setRequestMayBeNested()
* \since QGIS 3.4
*/
bool requestMayBeNested() const;
/**
* In case this request may be run nested within another already running
* iteration on the same connection, set this to TRUE.
*
* If this flag is TRUE, this request will be able to make use of "spare"
* connections to avoid deadlocks.
*
* For example, this should be set on requests that are issued from an
* expression function.
*
* \see requestMayBeNested()
* \since QGIS 3.4
*/
QgsFeatureRequest &setRequestMayBeNested( bool requestMayBeNested );
/**
* Attach a \a feedback object that can be queried regularly by the iterator to check
* if it should be canceled.
*
* Ownership of \a feedback is NOT transferred, and the caller must take care that it exists
* for the lifetime of the feature request and feature iterators.
*
* \see feedback()
*
* \since QGIS 3.20
*/
void setFeedback( QgsFeedback *feedback );
/**
* Returns the feedback object that can be queried regularly by the iterator to check
* if it should be canceled, if set.
*
* \see setFeedback()
*
* \since QGIS 3.20
*/
QgsFeedback *feedback() const;
protected:
/**
* Attribute/ID filter type.
*/
Qgis::FeatureRequestFilterType mFilter = Qgis::FeatureRequestFilterType::NoFilter;
/**
* Spatial filter type.
*
* \since QGIS 3.22
*/
Qgis::SpatialFilterType mSpatialFilter = Qgis::SpatialFilterType::NoFilter;
/**
* Bounding box for spatial filtering.
*/
QgsRectangle mFilterRect;
/**
* Reference geometry for Qgis::RequestSpatialFilter::DistanceWithin filtering.
*/
QgsGeometry mReferenceGeometry;
/**
* Prepared geometry engine for mReferenceGeometry.
*/
std::shared_ptr< QgsGeometryEngine > mReferenceGeometryEngine;
/**
* Maximum distance from reference geometry.
*/
double mDistanceWithin = 0;
QgsFeatureId mFilterFid = -1;
QgsFeatureIds mFilterFids;
std::unique_ptr< QgsExpression > mFilterExpression;
QgsExpressionContext mExpressionContext;
Qgis::FeatureRequestFlags mFlags;
QgsAttributeList mAttrs;
QgsSimplifyMethod mSimplifyMethod;
long long mLimit = -1;
OrderBy mOrderBy;
Qgis::InvalidGeometryCheck mInvalidGeometryFilter = Qgis::InvalidGeometryCheck::NoCheck;
std::function< void( const QgsFeature & ) > mInvalidGeometryCallback;
std::function< void( const QgsFeature & ) > mTransformErrorCallback;
QgsCoordinateReferenceSystem mCrs;
QgsCoordinateTransformContext mTransformContext;
int mTimeout = -1;
int mRequestMayBeNested = false;
QgsFeedback *mFeedback = nullptr;
};
class QgsFeatureIterator;
class QgsAbstractFeatureIterator;
/**
* \ingroup core
* \brief Base class that can be used for any class that is capable of returning features
*/
class CORE_EXPORT QgsAbstractFeatureSource
{
public:
virtual ~QgsAbstractFeatureSource();
// IMPORTANT -- do NOT remove the /TransferBack/ annotation here -- while it looks completely wrong, it's
// required for Python data providers to work correctly! Argh!
/**
* Gets an iterator for features matching the specified request
* \param request The request
* \returns A feature iterator
*/
virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) = 0 SIP_TRANSFERBACK;
// IMPORTANT -- do NOT remove the /TransferBack/ annotation here -- while it looks completely wrong, it's
// required for Python data providers to work correctly! Argh!
protected:
void iteratorOpened( QgsAbstractFeatureIterator *it );
void iteratorClosed( QgsAbstractFeatureIterator *it );
QSet< QgsAbstractFeatureIterator * > mActiveIterators;
template<typename> friend class QgsAbstractFeatureIteratorFromSource;
};
#endif // QGSFEATUREREQUEST_H