QgsFeaturePool documentation and thread safety cleanups

python/PyQt6/analysis/auto_generated/vector/geometry_checker/qgsfeaturepool.sip.in

@@ -30,6 +30,8 @@ A feature pool is based on a vector layer and caches features.
     QgsFeaturePool( QgsVectorLayer *layer );
 %Docstring
 Creates a new feature pool for ``layer``.
+
+Must be created on the same thread as ``layer``.
 %End
     virtual ~QgsFeaturePool();
 
@@ -38,19 +40,36 @@ Creates a new feature pool for ``layer``.
 Retrieves the feature with the specified ``id`` into ``feature``.
 It will be retrieved from the cache or from the underlying feature source if unavailable.
 If the feature is neither available from the cache nor from the source it will return ``False``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
 
     virtual void updateFeature( QgsFeature &feature ) = 0;
 %Docstring
 Updates a feature in this pool.
 Implementations will update the feature on the layer or on the data provider.
+
+.. warning::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread. The update will be delegated to run in the main thread, and care must
+   be taken to avoid deadlocks if the main thread is busy.
 %End
 
     virtual void deleteFeature( QgsFeatureId fid ) = 0;
 %Docstring
 Removes a feature from this pool.
 Implementations will remove the feature from the layer or from the data provider.
+
+.. warning::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread. The update will be delegated to run in the main thread, and care must
+   be taken to avoid deadlocks if the main thread is busy.
 %End
 
 
@@ -59,7 +78,10 @@ Implementations will remove the feature from the layer or from the data provider
 %Docstring
 Gets a pointer to the underlying layer.
 May return a ````None```` if the layer has been deleted.
-This must only be called from the main thread.
+
+.. warning::
+
+   This must be called from the same thread as the vector layer belongs to.
 %End
 
 
@@ -92,18 +114,33 @@ the background thread.
 %Docstring
 Inserts a feature into the cache and the spatial index.
 To be used by implementations of ``addFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
     void refreshCache( const QgsFeature &feature );
 %Docstring
 Changes a feature in the cache and the spatial index.
 To be used by implementations of ``updateFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
     void removeFeature( const QgsFeatureId featureId );
 %Docstring
 Removes a feature from the cache and the spatial index.
 To be used by implementations of ``deleteFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
 

python/analysis/auto_generated/vector/geometry_checker/qgsfeaturepool.sip.in

@@ -30,6 +30,8 @@ A feature pool is based on a vector layer and caches features.
     QgsFeaturePool( QgsVectorLayer *layer );
 %Docstring
 Creates a new feature pool for ``layer``.
+
+Must be created on the same thread as ``layer``.
 %End
     virtual ~QgsFeaturePool();
 
@@ -38,19 +40,36 @@ Creates a new feature pool for ``layer``.
 Retrieves the feature with the specified ``id`` into ``feature``.
 It will be retrieved from the cache or from the underlying feature source if unavailable.
 If the feature is neither available from the cache nor from the source it will return ``False``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
 
     virtual void updateFeature( QgsFeature &feature ) = 0;
 %Docstring
 Updates a feature in this pool.
 Implementations will update the feature on the layer or on the data provider.
+
+.. warning::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread. The update will be delegated to run in the main thread, and care must
+   be taken to avoid deadlocks if the main thread is busy.
 %End
 
     virtual void deleteFeature( QgsFeatureId fid ) = 0;
 %Docstring
 Removes a feature from this pool.
 Implementations will remove the feature from the layer or from the data provider.
+
+.. warning::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread. The update will be delegated to run in the main thread, and care must
+   be taken to avoid deadlocks if the main thread is busy.
 %End
 
 
@@ -59,7 +78,10 @@ Implementations will remove the feature from the layer or from the data provider
 %Docstring
 Gets a pointer to the underlying layer.
 May return a ````None```` if the layer has been deleted.
-This must only be called from the main thread.
+
+.. warning::
+
+   This must be called from the same thread as the vector layer belongs to.
 %End
 
 
@@ -92,18 +114,33 @@ the background thread.
 %Docstring
 Inserts a feature into the cache and the spatial index.
 To be used by implementations of ``addFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
     void refreshCache( const QgsFeature &feature );
 %Docstring
 Changes a feature in the cache and the spatial index.
 To be used by implementations of ``updateFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
     void removeFeature( const QgsFeatureId featureId );
 %Docstring
 Removes a feature from the cache and the spatial index.
 To be used by implementations of ``deleteFeature``.
+
+.. note::
+
+   This method can safely be called from a different thread vs the object's creation thread or
+   the original layer's thread.
 %End
 
 

src/analysis/vector/geometry_checker/qgsfeaturepool.cpp

@@ -32,9 +32,11 @@ QgsFeaturePool::QgsFeaturePool( QgsVectorLayer *layer )
   , mLayer( layer )
   , mGeometryType( layer->geometryType() )
   , mFeatureSource( std::make_unique<QgsVectorLayerFeatureSource>( layer ) )
+  , mLayerId( layer->id() )
   , mLayerName( layer->name() )
+  , mCrs( layer->crs() )
 {
-
+  Q_ASSERT( QThread::currentThread() == mLayer->thread() );
 }
 
 bool QgsFeaturePool::getFeature( QgsFeatureId id, QgsFeature &feature )
@@ -71,9 +73,10 @@ bool QgsFeaturePool::getFeature( QgsFeatureId id, QgsFeature &feature )
 
 QgsFeatureIds QgsFeaturePool::getFeatures( const QgsFeatureRequest &request, QgsFeedback *feedback )
 {
-  QgsReadWriteLocker( mCacheLock, QgsReadWriteLocker::Write );
+  QgsReadWriteLocker locker( mCacheLock, QgsReadWriteLocker::Write );
   Q_UNUSED( feedback )
-  Q_ASSERT( QThread::currentThread() == qApp->thread() );
+  Q_ASSERT( mLayer );
+  Q_ASSERT( QThread::currentThread() == mLayer->thread() );
 
   mFeatureCache.clear();
   mIndex = QgsSpatialIndex();
@@ -107,7 +110,8 @@ QgsFeatureIds QgsFeaturePool::getIntersects( const QgsRectangle &rect ) const
 
 QgsVectorLayer *QgsFeaturePool::layer() const
 {
-  Q_ASSERT( QThread::currentThread() == qApp->thread() );
+  if ( mLayer )
+    Q_ASSERT( QThread::currentThread() == mLayer->thread() );
 
   return mLayer.data();
 }
@@ -169,8 +173,7 @@ QString QgsFeaturePool::layerName() const
 
 QgsCoordinateReferenceSystem QgsFeaturePool::crs() const
 {
-  QgsReadWriteLocker( mCacheLock, QgsReadWriteLocker::Read );
-  return mFeatureSource->crs();
+  return mCrs;
 }
 
 Qgis::GeometryType QgsFeaturePool::geometryType() const
@@ -180,6 +183,5 @@ Qgis::GeometryType QgsFeaturePool::geometryType() const
 
 QString QgsFeaturePool::layerId() const
 {
-  QgsReadWriteLocker( mCacheLock, QgsReadWriteLocker::Read );
-  return mFeatureSource->id();
+  return mLayerId;
 }

src/analysis/vector/geometry_checker/qgsfeaturepool.h

@@ -41,6 +41,8 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
 
     /**
      * Creates a new feature pool for \a layer.
+     *
+     * Must be created on the same thread as \a layer.
      */
     QgsFeaturePool( QgsVectorLayer *layer );
     virtual ~QgsFeaturePool() = default;
@@ -49,6 +51,9 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
      * Retrieves the feature with the specified \a id into \a feature.
      * It will be retrieved from the cache or from the underlying feature source if unavailable.
      * If the feature is neither available from the cache nor from the source it will return FALSE.
+     *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
      */
     bool getFeature( QgsFeatureId id, QgsFeature &feature );
 
@@ -59,27 +64,40 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
      * are returned. This is used to warm the cache for a particular area of interest
      * (bounding box) or other set of features.
      * This will get a new feature source from the source vector layer.
-     * This needs to be called from the main thread.
+     *
      * If \a feedback is specified, the call may return if the feedback is canceled.
+     *
+     * \warning This must be called from the same thread as the vector layer belongs to.
      */
     QgsFeatureIds getFeatures( const QgsFeatureRequest &request, QgsFeedback *feedback = nullptr ) SIP_SKIP;
 
     /**
      * Updates a feature in this pool.
      * Implementations will update the feature on the layer or on the data provider.
+     *
+     * \warning This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread. The update will be delegated to run in the main thread, and care must
+     * be taken to avoid deadlocks if the main thread is busy.
      */
     virtual void updateFeature( QgsFeature &feature ) = 0;
 
     /**
      * Removes a feature from this pool.
      * Implementations will remove the feature from the layer or from the data provider.
+     *
+     * \warning This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread. The update will be delegated to run in the main thread, and care must
+     * be taken to avoid deadlocks if the main thread is busy.
      */
     virtual void deleteFeature( QgsFeatureId fid ) = 0;
 
     /**
      * Returns the complete set of feature ids in this pool.
      * Note that this concerns the features governed by this pool, which are not necessarily all cached.
      *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
+     *
      * \note not available in Python bindings
      */
     QgsFeatureIds allFeatureIds() const SIP_SKIP;
@@ -88,20 +106,25 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
      * Gets all feature ids in the bounding box \a rect. It will use a spatial index to
      * determine the ids.
      *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
+     *
      * \note not available in Python bindings
      */
     QgsFeatureIds getIntersects( const QgsRectangle &rect ) const SIP_SKIP;
 
     /**
      * Gets a pointer to the underlying layer.
      * May return a ``NULLPTR`` if the layer has been deleted.
-     * This must only be called from the main thread.
+     *
+     * \warning This must be called from the same thread as the vector layer belongs to.
      */
     QgsVectorLayer *layer() const;
 
     /**
      * Gets a QPointer to the underlying layer.
-     * Note that access to any methods of the object
+     *
+     * \warning Access to any methods of the object
      * will need to be done on the main thread and
      * the pointer will need to be checked for validity
      * before usage.
@@ -138,18 +161,27 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
     /**
      * Inserts a feature into the cache and the spatial index.
      * To be used by implementations of ``addFeature``.
+     *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
      */
     void insertFeature( const QgsFeature &feature, bool skipLock = false );
 
     /**
      * Changes a feature in the cache and the spatial index.
      * To be used by implementations of ``updateFeature``.
+     *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
      */
     void refreshCache( const QgsFeature &feature );
 
     /**
      * Removes a feature from the cache and the spatial index.
      * To be used by implementations of ``deleteFeature``.
+     *
+     * \note This method can safely be called from a different thread vs the object's creation thread or
+     * the original layer's thread.
      */
     void removeFeature( const QgsFeatureId featureId );
 
@@ -184,7 +216,9 @@ class ANALYSIS_EXPORT QgsFeaturePool : public QgsFeatureSink SIP_ABSTRACT
     QgsSpatialIndex mIndex;
     Qgis::GeometryType mGeometryType;
     std::unique_ptr<QgsVectorLayerFeatureSource> mFeatureSource;
+    QString mLayerId;
     QString mLayerName;
+    QgsCoordinateReferenceSystem mCrs;
 };
 
 #endif // QGS_FEATUREPOOL_H