[processing] fix fTools Clip algorithm (fix #7281)

Author: alexbruy

python/plugins/processing/algs/ftools/Clip.py

@@ -26,14 +26,15 @@
 from PyQt4.QtCore import *
 from qgis.core import *
 from processing.core.GeoAlgorithm import GeoAlgorithm
-from processing.tools import dataobjects, vector
 from processing.core.ProcessingLog import ProcessingLog
 from processing.parameters.ParameterVector import ParameterVector
 from processing.outputs.OutputVector import OutputVector
+from processing.tools import dataobjects, vector
 from processing.tools import vector as utils
 
 class Clip(GeoAlgorithm):
 
+
     INPUT = "INPUT"
     OVERLAY = "OVERLAY"
     OUTPUT = "OUTPUT"
@@ -66,33 +67,44 @@ def processAlgorithm(self, progress):
         for inFeatA in selectionA:
             geom = QgsGeometry(inFeatA.geometry())
             attrs = inFeatA.attributes()
-            intersections = index.intersects(geom.boundingBox())
+            intersects = index.intersects(geom.boundingBox())
             first = True
             found = False
-            if len(intersections) > 0:
-                for i in intersections:
-                    request = QgsFeatureRequest().setFilterFid(i)
-                    inFeatB = layerB.getFeatures(request).next()
+            if len(intersects) > 0:
+                for i in intersects:
+                    layerB.getFeatures(QgsFeatureRequest().setFilterFid(i)).nextFeature(inFeatB)
                     tmpGeom = QgsGeometry(inFeatB.geometry())
                     if tmpGeom.intersects(geom):
                         found = True
                         if first:
                             outFeat.setGeometry(QgsGeometry(tmpGeom))
                             first = False
                         else:
-                            cur_geom = QgsGeometry(outFeat.geometry())
-                            new_geom = QgsGeometry(cur_geom.combine(tmpGeom))
-                            outFeat.setGeometry(QgsGeometry(new_geom))
-                if found:               
-                    cur_geom = QgsGeometry(outFeat.geometry())
-                    new_geom = QgsGeometry(geom.intersection(cur_geom))
-                    if new_geom.wkbType() == QGis.WKBNoGeometry :
-                        int_com = QgsGeometry(geom.combine(cur_geom))
-                        int_sym = QgsGeometry(geom.symDifference(cur_geom))
-                        new_geom = QgsGeometry(int_com.difference(int_sym))                        
-                    outFeat.setGeometry(new_geom)
-                    outFeat.setAttributes(attrs)
-                    writer.addFeature(outFeat)                                        
+                            try:
+                                cur_geom = QgsGeometry(outFeat.geometry())
+                                new_geom = QgsGeometry(cur_geom.combine(tmpGeom))
+                                outFeat.setGeometry(QgsGeometry(new_geom))
+                            except:
+                                ProcessingLog.addToLog(ProcessingLog.LOG_ERROR, "GEOS geoprocessing error: One or more input features have invalid geometry.")
+                                break
+                if found:
+                    try:
+                        cur_geom = QgsGeometry(outFeat.geometry())
+                        new_geom = QgsGeometry(geom.intersection(cur_geom))
+                        if new_geom.wkbType() == 0:
+                            int_com = QgsGeometry(geom.combine(cur_geom))
+                            int_sym = QgsGeometry(geom.symDifference(cur_geom))
+                            new_geom = QgsGeometry(int_com.difference(int_sym))
+                        try:
+                            outFeat.setGeometry(new_geom)
+                            outFeat.setAttributes(attrs)
+                            writer.addFeature(outFeat)
+                        except:
+                            ProcessingLog.addToLog(ProcessingLog.LOG_ERROR, "Feature geometry error: One or more output features ignored due to invalid geometry.")
+                            continue
+                    except:
+                        ProcessingLog.addToLog(ProcessingLog.LOG_ERROR, "GEOS geoprocessing error: One or more input features have invalid geometry.")
+                        continue
 
             current += 1
             progress.setPercentage(int(current * total))