Sketcher: Add Sketcher Geometry Extension

src/Mod/Sketcher/App/AppSketcher.cpp

@@ -65,12 +65,13 @@ PyMOD_INIT_FUNC(Sketcher)
     // call PyType_Ready, otherwise we run into a segmentation fault, later on.
     // This function is responsible for adding inherited slots from a type's base class.
 
-    Sketcher::SketchObjectSF        ::init();
-    Sketcher::SketchObject          ::init();
-    Sketcher::SketchObjectPython    ::init();
-    Sketcher::Sketch                ::init();
-    Sketcher::Constraint            ::init();
-    Sketcher::PropertyConstraintList::init();
+    Sketcher::SketchGeometryExtension	::init();
+    Sketcher::SketchObjectSF        	::init();
+    Sketcher::SketchObject          	::init();
+    Sketcher::SketchObjectPython    	::init();
+    Sketcher::Sketch                	::init();
+    Sketcher::Constraint            	::init();
+    Sketcher::PropertyConstraintList	::init();
 
     Base::Console().Log("Loading Sketcher module... done\n");
 

src/Mod/Sketcher/App/SketchObject.cpp

@@ -88,6 +88,41 @@
 using namespace Sketcher;
 using namespace Base;
 
+//---------- Geometry Extension
+
+TYPESYSTEM_SOURCE(Sketcher::SketchGeometryExtension,Part::GeometryExtension)
+
+SketchGeometryExtension::~SketchGeometryExtension()
+{
+}
+
+// Persistence implementer
+unsigned int SketchGeometryExtension::getMemSize (void) const
+{
+    return sizeof(long int);
+}
+
+void SketchGeometryExtension::Save(Base::Writer &writer) const
+{
+
+    writer.Stream() << writer.ind() << "<GeoExtension type=\"" << this->getTypeId().getName()
+                    << "\" id=\"" << id << "\"/>" << endl;
+}
+
+void SketchGeometryExtension::Restore(Base::XMLReader &reader)
+{
+    id = reader.getAttributeAsInteger("id");
+}
+
+PyObject * SketchGeometryExtension::getPyObject(void)
+{
+    return 0;
+}
+
+
+//-------------- End Geometry Extension
+
+
 const int GeoEnum::RtPnt  = -1;
 const int GeoEnum::HAxis  = -1;
 const int GeoEnum::VAxis  = -2;

src/Mod/Sketcher/App/SketchObject.h

@@ -41,6 +41,23 @@
 namespace Sketcher
 {
 
+class SketcherExport SketchGeometryExtension : public Part::GeometryExtension
+{
+    TYPESYSTEM_HEADER();
+public:
+    virtual ~SketchGeometryExtension();
+
+    // Persistence implementer ---------------------
+    virtual unsigned int getMemSize(void) const;
+    virtual void Save(Base::Writer &/*writer*/) const;
+    virtual void Restore(Base::XMLReader &/*reader*/);
+
+    virtual PyObject *getPyObject(void);
+
+public:
+    long int id;
+};
+
 struct SketcherExport GeoEnum
 {
     static const int RtPnt;