Adds a 'new' function to the SbkBaseWrapperType meta type.

When a Python programmer extends a wrapped C++ class the newly created
type must inherit its parent class' special information (e.g. multiple
inheritance casting). The 'new' function for the wrapper meta type
copies the parent information for the extended type.

As it is now the meta type new works properly only with a Python class
inheriting from a single wrapped C++ type.

Reviewed by Hugo Parente <hugo.lima@openbossa.org>

1 files changed, 21 insertions, 1 deletions

diff --git a/libshiboken/basewrapper.cpp b/libshiboken/basewrapper.cpp
index 05276b7fa..6ec023465 100644
--- a/libshiboken/basewrapper.cpp
+++ b/libshiboken/basewrapper.cpp
@@ -215,6 +215,26 @@ bool importModule(const char* moduleName, PyTypeObject*** cppApiPtr)
 
 // Wrapper metatype and base type ----------------------------------------------------------
 
+static PyObject*
+SbkBaseWrapperType_TpNew(PyTypeObject* metatype, PyObject* args, PyObject* kwds)
+{
+    // The meta type creates a new type when the Python programmer extends a wrapped C++ class.
+    SbkBaseWrapperType* newType = reinterpret_cast<SbkBaseWrapperType*>(PyType_Type.tp_new(metatype, args, kwds));
+
+    if (!newType)
+        return 0;
+
+    // This expects that Python classes will inherit from only one C++ wrapped class.
+    SbkBaseWrapperType* parentType = reinterpret_cast<SbkBaseWrapperType*>(PyTuple_GET_ITEM(PyTuple_GET_ITEM(args, 1), 0));
+
+    newType->mi_offsets = parentType->mi_offsets;
+    newType->mi_init = parentType->mi_init;
+    newType->mi_specialcast = parentType->mi_specialcast;
+    newType->type_name_func = parentType->type_name_func;
+
+    return reinterpret_cast<PyObject*>(newType);
+}
+
 extern "C"
 {
 
@@ -259,7 +279,7 @@ PyTypeObject SbkBaseWrapperType_Type = {
     /*tp_dictoffset*/       0,
     /*tp_init*/             0,
     /*tp_alloc*/            0,
-    /*tp_new*/              0,
+    /*tp_new*/              SbkBaseWrapperType_TpNew,
     /*tp_free*/             0,
     /*tp_is_gc*/            0,
     /*tp_bases*/            0,