Port Attacher codde to the extension framework

AttachableObjects are desired in multiple occasions, and the current AttachableObject is not flexible enough to handle all cases. Hence the code is portet to an extension, which gives the needed flexibility.

src/Mod/Part/App/AttachExtensionPyImp.cpp

@@ -0,0 +1,87 @@
+
+#include "PreCompiled.h"
+
+#include "Mod/Part/App/AttachExtension.h"
+#include "OCCError.h"
+
+#include "AttachEnginePy.h"
+
+// inclusion of the generated files (generated out of AttachExtensionPy.xml)
+#include "AttachExtensionPy.h"
+#include "AttachExtensionPy.cpp"
+
+using namespace Part;
+
+// returns a string which represents the object e.g. when printed in python
+std::string AttachExtensionPy::representation(void) const
+{
+    return std::string("<Part::AttachableObject>");
+}
+
+PyObject* AttachExtensionPy::positionBySupport(PyObject *args)
+{
+    if (!PyArg_ParseTuple(args, ""))
+        return 0;
+    bool bAttached = false;
+    try{
+        bAttached = this->getAttachExtensionPtr()->positionBySupport();
+    } catch (Standard_Failure) {
+        Handle_Standard_Failure e = Standard_Failure::Caught();
+        PyErr_SetString(PartExceptionOCCError, e->GetMessageString());
+        return NULL;
+    } catch (Base::Exception &e) {
+        PyErr_SetString(Base::BaseExceptionFreeCADError, e.what());
+        return NULL;
+    }
+    return Py::new_reference_to(Py::Boolean(bAttached));
+}
+
+PyObject* AttachExtensionPy::changeAttacherType(PyObject *args)
+{
+    const char* typeName;
+    if (!PyArg_ParseTuple(args, "s", &typeName))
+        return 0;
+    bool ret;
+    try{
+        ret = this->getAttachExtensionPtr()->changeAttacherType(typeName);
+    } catch (Standard_Failure) {
+        Handle_Standard_Failure e = Standard_Failure::Caught();
+        PyErr_SetString(PartExceptionOCCError, e->GetMessageString());
+        return NULL;
+    } catch (Base::Exception &e) {
+        PyErr_SetString(Base::BaseExceptionFreeCADError, e.what());
+        return NULL;
+    }
+    return Py::new_reference_to(Py::Boolean(ret));
+}
+
+Py::Object AttachExtensionPy::getAttacher(void) const
+{
+    try {
+        this->getAttachExtensionPtr()->attacher(); //throws if attacher is not set
+    } catch (Base::Exception) {
+        return Py::None();
+    }
+
+    try {
+        return Py::Object( new Attacher::AttachEnginePy(this->getAttachExtensionPtr()->attacher().copy()), true);
+    } catch (Standard_Failure) {
+        Handle_Standard_Failure e = Standard_Failure::Caught();
+        throw Py::Exception(Part::PartExceptionOCCError, e->GetMessageString());
+    } catch (Base::Exception &e) {
+        throw Py::Exception(Base::BaseExceptionFreeCADError, e.what());
+    }
+
+}
+
+PyObject *AttachExtensionPy::getCustomAttributes(const char* /*attr*/) const
+{
+    return 0;
+}
+
+int AttachExtensionPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
+{
+    return 0;
+}
+
+