Modified the BindingManager::getOverride method to use Python __mro__.

Using the CLASS->tp_mro, which contains the list of method resolution for
a Python class, to find an override for a wrapped C++ virtual method is
more correct than relying in the ShiboTypeObject's baseWrapperType value.
Also baseWrapperType was removed from ShiboTypeObject structure.

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

3 files changed, 21 insertions, 19 deletions

diff --git a/libshiboken/basewrapper.cpp b/libshiboken/basewrapper.cpp
index 75af9b5fd..3a2bc9964 100644
--- a/libshiboken/basewrapper.cpp
+++ b/libshiboken/basewrapper.cpp
@@ -105,7 +105,6 @@ void destroyParentInfo(PyBaseWrapper* obj, bool removeFromParent)
 }
 
 PyObject* PyBaseWrapper_New(PyTypeObject* instanceType,
-                            ShiboTypeObject* baseWrapperType,
                             const void* cptr,
                             unsigned int hasOwnership,
                             unsigned int containsCppWrapper)
@@ -116,7 +115,6 @@ PyObject* PyBaseWrapper_New(PyTypeObject* instanceType,
     ShiboTypeObject* const& instanceType_ = reinterpret_cast<ShiboTypeObject*>(instanceType);
     PyBaseWrapper* self = (PyBaseWrapper*)instanceType_->pytype.tp_alloc((PyTypeObject*) instanceType, 0);
 
-    self->baseWrapperType = baseWrapperType;
     self->cptr = const_cast<void*>(cptr);
     self->hasOwnership = hasOwnership;
     self->containsCppWrapper = containsCppWrapper;
diff --git a/libshiboken/basewrapper.h b/libshiboken/basewrapper.h
index 90c38c735..56038c4ca 100644
--- a/libshiboken/basewrapper.h
+++ b/libshiboken/basewrapper.h
@@ -75,8 +75,6 @@ struct LIBSHIBOKEN_API ShiboTypeObject
 struct LIBSHIBOKEN_API PyBaseWrapper
 {
     PyObject_HEAD
-    /// First binding provided parent type of a Python class that inherits from a wrapped class.
-    ShiboTypeObject* baseWrapperType;
     /// Pointer to the C++ class.
     void* cptr;
     /// True when Python is responsible for freeing the used memory.
@@ -174,7 +172,6 @@ typedef struct {
 
 LIBSHIBOKEN_API PyAPI_FUNC(PyObject*)
 PyBaseWrapper_New(PyTypeObject* instanceType,
-                  ShiboTypeObject* baseWrapperType,
                   const void *cptr,
                   unsigned int hasOwnership = 1,
                   unsigned int containsCppWrapper = 0);
diff --git a/libshiboken/bindingmanager.cpp b/libshiboken/bindingmanager.cpp
index 8c8be3e46..5788b1108 100644
--- a/libshiboken/bindingmanager.cpp
+++ b/libshiboken/bindingmanager.cpp
@@ -109,25 +109,32 @@ PyObject* BindingManager::retrieveWrapper(const void* cptr)
 PyObject* BindingManager::getOverride(const void* cptr, const char* methodName)
 {
     PyObject* wrapper = retrieveWrapper(cptr);
+    if (!wrapper)
+        return 0;
 
-    if (wrapper) {
-        PyTypeObject* baseWrapperType = (PyTypeObject*) ((Shiboken::PyBaseWrapper*)wrapper)->baseWrapperType;
-        PyObject* method = PyObject_GetAttrString(wrapper, const_cast<char*>(methodName));
-        if (method) {
-            PyObject* defaultMethod = 0;
-            if (PyMethod_Check(method) &&
-                ((PyMethodObject*) method)->im_self == wrapper &&
-                baseWrapperType->tp_dict != 0) {
-                defaultMethod = PyDict_GetItemString(baseWrapperType->tp_dict, const_cast<char*>(methodName));
+    PyObject* pyMethodName = PyString_FromString(methodName);
+    PyObject* method = PyObject_GetAttr(wrapper, pyMethodName);
+
+    if (method && PyMethod_Check(method) && reinterpret_cast<PyMethodObject*>(method)->im_self == wrapper) {
+        PyObject* defaultMethod;
+        PyObject* mro = wrapper->ob_type->tp_mro;
+
+        // The first class in the mro (index 0) is the class being checked and it should not be tested.
+        // The last class in the mro (size - 1) is the base Python object class which should not be tested also.
+        for (int i = 1; i < PyTuple_GET_SIZE(mro) - 1; i++) {
+            PyTypeObject* parent = reinterpret_cast<PyTypeObject*>(PyTuple_GET_ITEM(mro, i));
+            if (parent->tp_dict) {
+                defaultMethod = PyDict_GetItem(parent->tp_dict, pyMethodName);
+                if (defaultMethod && reinterpret_cast<PyMethodObject*>(method)->im_func != defaultMethod) {
+                    Py_DECREF(pyMethodName);
+                    return method;
+                }
             }
-
-            if (defaultMethod && ((PyMethodObject*)method)->im_func != defaultMethod)
-                return method;
-
-            Py_DECREF(method);
         }
     }
 
+    Py_XDECREF(method);
+    Py_DECREF(pyMethodName);
     return 0;
 }