Sketcher: GeometryFacade and ExternalGeometryFacade nullptr creation

====================================================================

If the Part::Geometry * is nullptr, then it is convenient to have a
std::unique<GeometryFacade> that contains a nullptr too, because many
functions check for a Part::Geometry being a nullptr.

src/Mod/Sketcher/App/ExternalGeometryFacade.cpp

@@ -54,14 +54,18 @@ ExternalGeometryFacade::ExternalGeometryFacade(const Part::Geometry * geometry)
 
 std::unique_ptr<ExternalGeometryFacade> ExternalGeometryFacade::getFacade(Part::Geometry * geometry)
 {
-    return std::unique_ptr<ExternalGeometryFacade>(new ExternalGeometryFacade(geometry));
-    //return std::make_unique<ExternalGeometryFacade>(geometry); // make_unique has no access to private constructor
+     if(geometry != nullptr)
+        return std::unique_ptr<ExternalGeometryFacade>(new ExternalGeometryFacade(geometry));
+     else
+        return std::unique_ptr<ExternalGeometryFacade>(nullptr);
 }
 
 std::unique_ptr<const ExternalGeometryFacade> ExternalGeometryFacade::getFacade(const Part::Geometry * geometry)
 {
-    return std::unique_ptr<const ExternalGeometryFacade>(new ExternalGeometryFacade(geometry));
-    //return std::make_unique<const ExternalGeometryFacade>(geometry); // make_unique has no access to private constructor
+     if(geometry != nullptr)
+        return std::unique_ptr<const ExternalGeometryFacade>(new ExternalGeometryFacade(geometry));
+     else
+        return std::unique_ptr<const ExternalGeometryFacade>(nullptr);
 }
 
 void ExternalGeometryFacade::setGeometry(Part::Geometry *geometry)

src/Mod/Sketcher/App/GeometryFacade.cpp

@@ -50,17 +50,24 @@ GeometryFacade::GeometryFacade(const Part::Geometry * geometry)
         initExtension();
     else
         THROWM(Base::ValueError, "GeometryFacade initialized with Geometry null pointer");
+
 }
 
 std::unique_ptr<GeometryFacade> GeometryFacade::getFacade(Part::Geometry * geometry)
 {
-    return std::unique_ptr<GeometryFacade>(new GeometryFacade(geometry));
+    if(geometry != nullptr)
+        return std::unique_ptr<GeometryFacade>(new GeometryFacade(geometry));
+    else
+        return std::unique_ptr<GeometryFacade>(nullptr);
     //return std::make_unique<GeometryFacade>(geometry); // make_unique has no access to private constructor
 }
 
 std::unique_ptr<const GeometryFacade> GeometryFacade::getFacade(const Part::Geometry * geometry)
 {
-    return std::unique_ptr<const GeometryFacade>(new GeometryFacade(geometry));
+    if(geometry != nullptr)
+        return std::unique_ptr<const GeometryFacade>(new GeometryFacade(geometry));
+     else
+        return std::unique_ptr<const GeometryFacade>(nullptr);
     //return std::make_unique<const GeometryFacade>(geometry); // make_unique has no access to private constructor
 }
 

src/Mod/Sketcher/App/GeometryFacade.h

@@ -222,10 +222,16 @@ class SketcherExport GeometryTypedFacade : public GeometryFacade
 
 public: // Factory methods
     static std::unique_ptr<GeometryTypedFacade<GeometryT>> getTypedFacade(GeometryT * geometry) {
-        return std::unique_ptr<GeometryTypedFacade<GeometryT>>(new GeometryTypedFacade(geometry));
+        if(geometry != nullptr)
+            return std::unique_ptr<GeometryTypedFacade<GeometryT>>(new GeometryTypedFacade(geometry));
+        else
+            return std::unique_ptr<GeometryTypedFacade<GeometryT>>(nullptr);
     }
     static std::unique_ptr<const GeometryTypedFacade<GeometryT>> getTypedFacade(const GeometryT * geometry) {
-        return std::unique_ptr<const GeometryTypedFacade<GeometryT>>(new GeometryTypedFacade(geometry));
+        if(geometry != nullptr)
+            return std::unique_ptr<const GeometryTypedFacade<GeometryT>>(new GeometryTypedFacade(geometry));
+        else
+            return std::unique_ptr<const GeometryTypedFacade<GeometryT>>(nullptr);
     }
 
     template < typename... Args >