From 595f104830877c494c8ff28e2f1b9fe500ef7123 Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Mon, 24 Apr 2017 16:33:57 +1000
Subject: [PATCH] Allow specifying a callback for encountering invalid
 geometries while iterating

---
 src/core/qgsfeaturerequest.cpp             |  6 ++++++
 src/core/qgsfeaturerequest.h               | 20 ++++++++++++++++++++
 src/core/qgsvectorlayerfeatureiterator.cpp |  6 +++++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/core/qgsfeaturerequest.cpp b/src/core/qgsfeaturerequest.cpp
index e8aec6e09ac6..c2efa9837dc3 100644
--- a/src/core/qgsfeaturerequest.cpp
+++ b/src/core/qgsfeaturerequest.cpp
@@ -111,6 +111,12 @@ QgsFeatureRequest &QgsFeatureRequest::setInvalidGeometryCheck( QgsFeatureRequest
   return *this;
 }
 
+QgsFeatureRequest &QgsFeatureRequest::setInvalidGeometryCallback( std::function<void ( const QgsFeature & )> callback )
+{
+  mInvalidGeometryCallback = callback;
+  return *this;
+}
+
 QgsFeatureRequest &QgsFeatureRequest::setFilterExpression( const QString &expression )
 {
   mFilter = FilterExpression;
diff --git a/src/core/qgsfeaturerequest.h b/src/core/qgsfeaturerequest.h
index 6e730764301a..50dcd31165bc 100644
--- a/src/core/qgsfeaturerequest.h
+++ b/src/core/qgsfeaturerequest.h
@@ -294,6 +294,25 @@ class CORE_EXPORT QgsFeatureRequest
      */
     InvalidGeometryCheck invalidGeometryCheck() const { return mInvalidGeometryFilter; }
 
+    /**
+     * 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
+     * \note not available in Python bindings
+     * \see invalidGeometryCallback()
+     */
+    QgsFeatureRequest &setInvalidGeometryCallback( std::function< void( const QgsFeature & ) > callback );
+
+    /**
+     * 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()
+     */
+    std::function< void( const QgsFeature & ) > invalidGeometryCallback() const { return mInvalidGeometryCallback; }
+
     /** Set the filter expression. {\see QgsExpression}
      * \param expression expression string
      * \see filterExpression
@@ -440,6 +459,7 @@ class CORE_EXPORT QgsFeatureRequest
     long mLimit = -1;
     OrderBy mOrderBy;
     InvalidGeometryCheck mInvalidGeometryFilter = GeometryNoCheck;
+    std::function< void( const QgsFeature & ) > mInvalidGeometryCallback;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsFeatureRequest::Flags )
diff --git a/src/core/qgsvectorlayerfeatureiterator.cpp b/src/core/qgsvectorlayerfeatureiterator.cpp
index c3ec663b4e09..4a181fa0b531 100644
--- a/src/core/qgsvectorlayerfeatureiterator.cpp
+++ b/src/core/qgsvectorlayerfeatureiterator.cpp
@@ -698,8 +698,12 @@ bool QgsVectorLayerFeatureIterator::checkGeometry( const QgsFeature &feature )
     case QgsFeatureRequest::GeometryAbortOnInvalid:
       if ( !feature.geometry().isGeosValid() )
       {
-        QgsMessageLog::logMessage( QObject::tr( "Geometry error: One or more input features have invalid geometry." ), QString(), QgsMessageLog::CRITICAL);
+        QgsMessageLog::logMessage( QObject::tr( "Geometry error: One or more input features have invalid geometry." ), QString(), QgsMessageLog::CRITICAL );
         close();
+        if ( mRequest.invalidGeometryCallback() )
+        {
+          mRequest.invalidGeometryCallback()( feature );
+        }
         return false;
       }
       break;