[processing] fixes extract by location alg (fixes #10241)

Author: slarosa

python/plugins/processing/algs/qgis/ftools/ExtractByLocation.py

@@ -55,6 +55,10 @@ def processAlgorithm(self, progress):
         filename = self.getParameterValue(self.INTERSECT)
         selectLayer = dataobjects.getObjectFromUri(filename)
         index = vector.spatialindex(layer)
+        
+        output = self.getOutputFromName(self.OUTPUT)
+        writer = output.getVectorWriter(layer.pendingFields(),
+                layer.dataProvider().geometryType(), layer.crs())
 
         geom = QgsGeometry()
         selectedSet = []
@@ -73,12 +77,8 @@ def processAlgorithm(self, progress):
                     selectedSet.append(feat.id())
             progress.setPercentage(int(current * total))
 
-        output = self.getOutputFromName(self.OUTPUT)
-        writer = output.getVectorWriter(layer.layer.pendingFields().toList(),
-                layer.geometryType(), layer.crs())
-
-        for (i, feat) in enumerate(features):
-            if feat.id() in selectedSet:
-                writer.addFeature(feat)
+        for i, f in enumerate(vector.features(layer)):
+            if f.id() in selectedSet:
+                writer.addFeature(f)
             progress.setPercentage(100 * i / float(featureCount))
         del writer