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4c8b801791
bool(obj) in Python has the following semantics: 1. if the object has __bool__() method, return its value 2. if the object has __len__() method, return its value 3. return True So for objects in QGIS API that implement __len__() method, we were getting unexpected behavior - for example, "if layer: ..." would evaluate as False in case the layer was empty, while the usual expectation is that any reference to an object that is not None should evaluate to True.
312 lines
9.7 KiB
Plaintext
312 lines
9.7 KiB
Plaintext
/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/core/qgsvectorlayercache.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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************************************************************************/
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class QgsVectorLayerCache : QObject
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{
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%Docstring
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This class caches features of a given QgsVectorLayer.
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The cached features can be indexed by QgsAbstractCacheIndex.
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Proper indexing for a given use-case may speed up performance substantially.
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%End
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%TypeHeaderCode
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#include "qgsvectorlayercache.h"
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%End
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public:
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public:
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QgsVectorLayerCache( QgsVectorLayer *layer, int cacheSize, QObject *parent /TransferThis/ = 0 );
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~QgsVectorLayerCache();
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void setCacheSize( int cacheSize );
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%Docstring
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Sets the maximum number of features to keep in the cache. Some features will be removed from
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the cache if the number is smaller than the previous size of the cache.
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:param cacheSize: indicates the maximum number of features to keep in the cache
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%End
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int cacheSize();
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%Docstring
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Returns the maximum number of features this cache will hold.
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In case full caching is enabled, this number can change, as new features get added.
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:return: int
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%End
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void setCacheGeometry( bool cacheGeometry );
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%Docstring
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Enable or disable the caching of geometries
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:param cacheGeometry: Enable or disable the caching of geometries
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.. seealso:: :py:func:`cacheGeometry`
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%End
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bool cacheGeometry() const;
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%Docstring
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Returns true if the cache will fetch and cache feature geometries.
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.. seealso:: :py:func:`setCacheGeometry`
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.. versionadded:: 3.0
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%End
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void setCacheSubsetOfAttributes( const QgsAttributeList &attributes );
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%Docstring
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Set the subset of attributes to be cached
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:param attributes: The attributes to be cached
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%End
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void setCacheAddedAttributes( bool cacheAddedAttributes );
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%Docstring
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If this is enabled, the subset of cached attributes will automatically be extended
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to also include newly added attributes.
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:param cacheAddedAttributes: Automatically cache new attributes
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%End
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void setFullCache( bool fullCache );
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%Docstring
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This enables or disables full caching.
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If enabled, all features will be held in the cache. The cache size will incrementally
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be increased to offer space for all features.
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When enabled, all features will be read into cache. As this feature will most likely
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be used for slow data sources, be aware, that the call to this method might take a long time.
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:param fullCache: True: enable full caching, False: disable full caching
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.. note::
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when a cache is invalidated() (e.g. by adding an attribute to a layer) this setting
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is reset. A full cache rebuild must be performed by calling setFullCache( true ) again.
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.. seealso:: :py:func:`hasFullCache`
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%End
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bool hasFullCache() const;
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%Docstring
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Returns true if the cache is complete, ie it contains all features. This may happen as
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a result of a call to setFullCache() or by through a feature request which resulted in
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all available features being cached.
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.. seealso:: :py:func:`setFullCache`
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.. versionadded:: 3.0
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%End
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void addCacheIndex( QgsAbstractCacheIndex *cacheIndex /Transfer/ );
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%Docstring
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Adds a QgsAbstractCacheIndex to this cache. Cache indices know about features present
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in this cache and decide, if enough information is present in the cache to respond to a :py:class:`QgsFeatureRequest`.
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The layer cache will take ownership of the index.
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:param cacheIndex: The cache index to add.
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%End
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QgsFeatureIterator getFeatures( const QgsFeatureRequest &featureRequest = QgsFeatureRequest() );
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%Docstring
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Query this VectorLayerCache for features.
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If the VectorLayerCache (and moreover any of its indices) is able to satisfy
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the request, the returned QgsFeatureIterator will iterate over cached features.
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If it's not possible to fully satisfy the request from the cache, part or all of the features
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will be requested from the data provider.
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:param featureRequest: The request specifying filter and required data.
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:return: An iterator over the requested data.
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%End
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QgsFeatureIterator getFeatures( const QString &expression );
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%Docstring
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Query the layer for features matching a given expression.
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%End
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QgsFeature getFeature( QgsFeatureId fid );
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%Docstring
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Query the layer for the feature with the given id.
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If there is no such feature, the returned feature will be invalid.
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%End
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QgsFeatureIterator getFeatures( const QgsFeatureIds &fids );
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%Docstring
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Query the layer for the features with the given ids.
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%End
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QgsFeatureIterator getFeatures( const QgsRectangle &rectangle );
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%Docstring
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Query the layer for the features which intersect the specified rectangle.
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%End
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bool isFidCached( QgsFeatureId fid ) const;
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%Docstring
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Check if a certain feature id is cached.
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:param fid: The feature id to look for
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:return: True if this id is in the cache
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.. seealso:: :py:func:`cachedFeatureIds`
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%End
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QgsFeatureIds cachedFeatureIds() const;
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%Docstring
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Returns the set of feature IDs for features which are cached.
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.. seealso:: :py:func:`isFidCached`
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.. versionadded:: 3.0
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%End
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bool featureAtId( QgsFeatureId featureId, QgsFeature &feature, bool skipCache = false );
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%Docstring
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Gets the feature at the given feature id. Considers the changed, added, deleted and permanent features
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:param featureId: The id of the feature to query
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:param feature: The result of the operation will be written to this feature
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:param skipCache: Will query the layer regardless if the feature is in the cache already
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:return: true in case of success
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%End
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bool removeCachedFeature( QgsFeatureId fid );
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%Docstring
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Removes the feature identified by fid from the cache if present.
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:param fid: The id of the feature to delete
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:return: true if the feature was removed, false if the feature id was not found in the cache
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%End
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QgsVectorLayer *layer();
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%Docstring
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Returns the layer to which this cache belongs
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%End
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QgsCoordinateReferenceSystem sourceCrs() const;
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%Docstring
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Returns the coordinate reference system for features in the cache.
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%End
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QgsFields fields() const;
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%Docstring
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Returns the fields associated with features in the cache.
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%End
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QgsWkbTypes::Type wkbType() const;
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%Docstring
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Returns the geometry type for features in the cache.
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%End
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int __len__() const;
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%Docstring
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Returns the number of features contained in the source, or -1
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if the feature count is unknown.
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%End
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%MethodCode
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sipRes = sipCpp->featureCount();
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%End
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//! Ensures that bool(obj) returns true (otherwise __len__() would be used)
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int __bool__() const;
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%MethodCode
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sipRes = true;
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%End
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long featureCount() const;
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%Docstring
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Returns the number of features contained in the source, or -1
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if the feature count is unknown.
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%End
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protected:
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void requestCompleted( const QgsFeatureRequest &featureRequest, const QgsFeatureIds &fids );
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%Docstring
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Gets called, whenever the full list of feature ids for a certain request is known.
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Broadcasts this information to indices, so they can update their tables.
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:param featureRequest: The feature request that was answered
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:param fids: The feature ids that have been returned
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%End
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void featureRemoved( QgsFeatureId fid );
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%Docstring
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Gets called, whenever a feature has been removed.
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Broadcasts this information to indices, so they can invalidate their cache if required.
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:param fid: The feature id of the removed feature.
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%End
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bool checkInformationCovered( const QgsFeatureRequest &featureRequest );
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%Docstring
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Checks if the information required to complete the request is cached.
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i.e. If all attributes required and the geometry is held in the cache.
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Please note, that this does not check, if the requested features are cached.
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:param featureRequest: The QgsFeatureRequest to be answered
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:return: True if the information is being cached, false if not
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%End
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signals:
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void finished();
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%Docstring
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When filling the cache, this signal gets emitted once the cache is fully initialized.
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%End
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void cachedLayerDeleted();
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%Docstring
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Is emitted when the cached layer is deleted. Is emitted when the cached layers layerDelete()
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signal is being emitted, but before the local reference to it has been set to NULL. So call to
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layer() will still return a valid pointer for cleanup purpose.
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%End
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void attributeValueChanged( QgsFeatureId fid, int field, const QVariant &value );
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%Docstring
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Is emitted when an attribute is changed. Is re-emitted after the layer itself emits this signal.
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You should connect to this signal, to be sure, to not get a cached value if querying the cache.
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%End
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void featureAdded( QgsFeatureId fid );
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%Docstring
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Is emitted, when a new feature has been added to the layer and this cache.
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You should connect to this signal instead of the layers', if you want to be sure
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that this cache has updated information for the new feature
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:param fid: The featureid of the changed feature
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%End
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void invalidated();
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%Docstring
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The cache has been invalidated and cleared. Note that when a cache is invalidated
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the fullCache() setting will be cleared, and a full cache rebuild via setFullCache( true )
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will need to be performed.
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%End
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};
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/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/core/qgsvectorlayercache.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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|
************************************************************************/
|