Allow setting the invalid geometry callback in processing context

Author: nyalldawson

python/core/processing/qgsprocessingcontext.sip

@@ -85,6 +85,29 @@ class QgsProcessingContext
  \see invalidGeometryCheck()
 %End
 
+
+    void setInvalidGeometryCallback( SIP_PYCALLABLE / AllowNone / );
+%Docstring
+ 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.
+.. versionadded:: 3.0
+ \see invalidGeometryCallback()
+%End
+%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
+    } );
+
+    Py_END_ALLOW_THREADS
+%End
+
+
 };
 QFlags<QgsProcessingContext::Flag> operator|(QgsProcessingContext::Flag f1, QFlags<QgsProcessingContext::Flag> f2);
 

src/core/processing/qgsprocessingcontext.h

@@ -93,12 +93,48 @@ class CORE_EXPORT QgsProcessingContext
      */
     void setInvalidGeometryCheck( const QgsFeatureRequest::InvalidGeometryCheck &check ) { mInvalidGeometryCheck = check; }
 
+
+    /**
+     * 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.
+     * \since QGIS 3.0
+     * \see invalidGeometryCallback()
+     */
+#ifndef SIP_RUN
+    void setInvalidGeometryCallback( std::function< void( const QgsFeature & ) > callback ) { mInvalidGeometryCallback = callback; }
+#else
+    void 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
+    } );
+
+    Py_END_ALLOW_THREADS
+    % End
+#endif
+
+    /**
+     * Returns the callback function to use when encountering an invalid geometry and
+     * invalidGeometryCheck() is set to GeometryAbortOnInvalid.
+     * \since QGIS 3.0
+     * \note not available in Python bindings
+     * \see setInvalidGeometryCallback()
+     */
+    SIP_SKIP std::function< void( const QgsFeature & ) > invalidGeometryCallback() const { return mInvalidGeometryCallback; }
+
   private:
 
     QgsProcessingContext::Flags mFlags = 0;
     QPointer< QgsProject > mProject;
     QgsExpressionContext mExpressionContext;
     QgsFeatureRequest::InvalidGeometryCheck mInvalidGeometryCheck = QgsFeatureRequest::GeometryNoCheck;
+    std::function< void( const QgsFeature & ) > mInvalidGeometryCallback;
 
 };
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsProcessingContext::Flags )

src/core/processing/qgsprocessingutils.cpp

@@ -179,6 +179,7 @@ QgsFeatureIterator QgsProcessingUtils::getFeatures( QgsVectorLayer *layer, const
 
   QgsFeatureRequest req( request );
   req.setInvalidGeometryCheck( context.invalidGeometryCheck() );
+  req.setInvalidGeometryCallback( context.invalidGeometryCallback() );
   if ( useSelection )
   {
     return layer->selectedFeaturesIterator( req );

tests/src/core/testqgsprocessing.cpp

@@ -501,12 +501,31 @@ void TestQgsProcessing::features()
   ids = getIds( QgsProcessingUtils::getFeatures( layer, context, QgsFeatureRequest().setFlags( QgsFeatureRequest::NoGeometry ) ) );
   QCOMPARE( ids, QgsFeatureIds() << 2 << 4 );
 
-#if 0
-  // test exception is raised when filtering invalid geoms
-  context.setInvalidGeometryCheck( QgsFeatureRequest.GeometryAbortOnInvalid )
-#endif
+  // test callback is hit when filtering invalid geoms
+  bool encountered = false;
+  std::function< void( const QgsFeature & ) > callback = [ &encountered ]( const QgsFeature & )
+  {
+    encountered = true;
+  };
+
+  context.setFlags( QgsProcessingContext::Flags( 0 ) );
+  context.setInvalidGeometryCheck( QgsFeatureRequest::GeometryAbortOnInvalid );
+  context.setInvalidGeometryCallback( callback );
+  QgsVectorLayer *polyLayer = new QgsVectorLayer( "Polygon", "v2", "memory" );
+  QgsFeature f;
+  f.setGeometry( QgsGeometry::fromWkt( QStringLiteral( "Polygon((0 0, 1 0, 0 1, 1 1, 0 0))" ) ) );
+  polyLayer->dataProvider()->addFeatures( QgsFeatureList() << f );
+
+  ids = getIds( QgsProcessingUtils::getFeatures( polyLayer, context ) );
+  QVERIFY( encountered );
+
+  encountered = false;
+  context.setInvalidGeometryCheck( QgsFeatureRequest::GeometryNoCheck );
+  ids = getIds( QgsProcessingUtils::getFeatures( polyLayer, context ) );
+  QVERIFY( !encountered );
 
   delete layer;
+  delete polyLayer;
 }
 
 QGSTEST_MAIN( TestQgsProcessing )