Fix bug 995 - "QDeclarativeView.itemAt returns faulty reference. (leading to SEGFAULT)"

5 files changed, 46 insertions, 9 deletions

diff --git a/libshiboken/basewrapper.cpp b/libshiboken/basewrapper.cpp
index 006b9c62a..8ccf89a6b 100644
--- a/libshiboken/basewrapper.cpp
+++ b/libshiboken/basewrapper.cpp
@@ -646,14 +646,21 @@ const char* getOriginalName(SbkObjectType* self)
     return self->d->original_name;
 }
 
-void setTypeDiscoveryFunction(SbkObjectType* self, TypeDiscoveryFunc func)
+void setTypeDiscoveryFunctionV2(SbkObjectType* self, TypeDiscoveryFuncV2 func)
 {
     self->d->type_discovery = func;
 }
 
+void setTypeDiscoveryFunction(SbkObjectType* self, TypeDiscoveryFunc func)
+{
+    self->d->type_discovery = (TypeDiscoveryFuncV2)func;
+}
+
 TypeDiscoveryFunc getTypeDiscoveryFunction(SbkObjectType* self)
 {
-    return self->d->type_discovery;
+    // This is an illegal cast because the return value is different,
+    // but nobody ever used this function, so... =]
+    return (TypeDiscoveryFunc)self->d->type_discovery;
 }
 
 void copyMultimpleheritance(SbkObjectType* self, SbkObjectType* other)
@@ -1017,7 +1024,7 @@ PyObject* newObject(SbkObjectType* instanceType,
                 instanceType = reinterpret_cast<SbkObjectType*>(tr->pythonType());
         }
         if (!tr)
-            instanceType = BindingManager::instance().resolveType(cptr, instanceType);
+            instanceType = BindingManager::instance().resolveType(&cptr, instanceType);
     }
 
     SbkObject* self = reinterpret_cast<SbkObject*>(SbkObjectTpNew(reinterpret_cast<PyTypeObject*>(instanceType), 0, 0));
diff --git a/libshiboken/basewrapper.h b/libshiboken/basewrapper.h
index 334ac6caf..4ce27ee13 100644
--- a/libshiboken/basewrapper.h
+++ b/libshiboken/basewrapper.h
@@ -64,6 +64,7 @@ typedef int* (*MultipleInheritanceInitFunction)(const void*);
  */
 typedef void* (*SpecialCastFunction)(void*, SbkObjectType*);
 typedef SbkObjectType* (*TypeDiscoveryFunc)(void*, SbkObjectType*);
+typedef void* (*TypeDiscoveryFuncV2)(void*, SbkObjectType*);
 
 typedef void* (*ExtendedToCppFunc)(PyObject*);
 typedef bool (*ExtendedIsConvertibleFunc)(PyObject*);
@@ -157,8 +158,9 @@ LIBSHIBOKEN_API void        setCastFunction(SbkObjectType* type, SpecialCastFunc
 LIBSHIBOKEN_API void        setOriginalName(SbkObjectType* self, const char* name);
 LIBSHIBOKEN_API const char* getOriginalName(SbkObjectType* self);
 
-LIBSHIBOKEN_API void        setTypeDiscoveryFunction(SbkObjectType* self, TypeDiscoveryFunc func);
-LIBSHIBOKEN_API TypeDiscoveryFunc getTypeDiscoveryFunction(SbkObjectType* self);
+LIBSHIBOKEN_API void setTypeDiscoveryFunctionV2(SbkObjectType* self, TypeDiscoveryFuncV2 func);
+LIBSHIBOKEN_API SBK_DEPRECATED(void setTypeDiscoveryFunction(SbkObjectType* self, TypeDiscoveryFunc func));
+LIBSHIBOKEN_API SBK_DEPRECATED(TypeDiscoveryFunc getTypeDiscoveryFunction(SbkObjectType* self));
 
 LIBSHIBOKEN_API void        copyMultimpleheritance(SbkObjectType* self, SbkObjectType* other);
 LIBSHIBOKEN_API void        setMultipleIheritanceFunction(SbkObjectType* self, MultipleInheritanceInitFunction func);
diff --git a/libshiboken/basewrapper_p.h b/libshiboken/basewrapper_p.h
index 35c9c83df..a00e1ad69 100644
--- a/libshiboken/basewrapper_p.h
+++ b/libshiboken/basewrapper_p.h
@@ -98,7 +98,7 @@ struct SbkObjectTypePrivate
 
     /// Special cast function, null if this class doesn't have multiple inheritance.
     SpecialCastFunction mi_specialcast;
-    TypeDiscoveryFunc type_discovery;
+    TypeDiscoveryFuncV2 type_discovery;
     /// Extended "isConvertible" function to be used when a conversion operator is defined in another module.
     ExtendedIsConvertibleFunc ext_isconvertible;
     /// Extended "toCpp" function to be used when a conversion operator is defined in another module.
diff --git a/libshiboken/bindingmanager.cpp b/libshiboken/bindingmanager.cpp
index efca2532a..a8d4b0a06 100644
--- a/libshiboken/bindingmanager.cpp
+++ b/libshiboken/bindingmanager.cpp
@@ -71,7 +71,7 @@ public:
     }
 #endif
 
-    SbkObjectType* identifyType(void* cptr, SbkObjectType* type, SbkObjectType* baseType) const
+    SbkObjectType* identifyType(void** cptr, SbkObjectType* type, SbkObjectType* baseType) const
     {
         Edges::const_iterator edgesIt = m_edges.find(type);
         if (edgesIt != m_edges.end()) {
@@ -83,7 +83,17 @@ public:
                     return newType;
             }
         }
-        return ((type->d && type->d->type_discovery) ? type->d->type_discovery(cptr, baseType) : 0);
+        void* typeFound = ((type->d && type->d->type_discovery) ? type->d->type_discovery(*cptr, baseType) : 0);
+        if (typeFound) {
+            // This "typeFound != type" is needed for backwards compatibility with old modules using a newer version of
+            // libshiboken because old versions of type_discovery function used to return a SbkObjectType* instead of
+            // a possible variation of the C++ instance pointer (*cptr).
+            if (typeFound != type)
+                *cptr = typeFound;
+            return type;
+        } else {
+            return 0;
+        }
     }
 };
 
@@ -265,6 +275,11 @@ void BindingManager::addClassInheritance(SbkObjectType* parent, SbkObjectType* c
 
 SbkObjectType* BindingManager::resolveType(void* cptr, SbkObjectType* type)
 {
+    return resolveType(&cptr, type);
+}
+
+SbkObjectType* BindingManager::resolveType(void** cptr, SbkObjectType* type)
+{
     SbkObjectType* identifiedType = m_d->classHierarchy.identifyType(cptr, type, type);
     return identifiedType ? identifiedType : type;
 }
diff --git a/libshiboken/bindingmanager.h b/libshiboken/bindingmanager.h
index e12558b4f..b43bd77b2 100644
--- a/libshiboken/bindingmanager.h
+++ b/libshiboken/bindingmanager.h
@@ -49,7 +49,20 @@ public:
     PyObject* getOverride(const void* cptr, const char* methodName);
 
     void addClassInheritance(SbkObjectType* parent, SbkObjectType* child);
-    SbkObjectType* resolveType(void* cptr, SbkObjectType* type);
+    /**
+     * \deprecated Use \fn resolveType(void**, SbkObjectType*), this version is broken when used with multiple inheritance
+     *             because the \p cptr pointer of the discovered type may be different of the given \p cptr in case
+     *             of multiple inheritance
+     */
+    SBK_DEPRECATED(SbkObjectType* resolveType(void* cptr, SbkObjectType* type));
+    /**
+     * Try to find the correct type of *cptr knowing that it's at least of type \p type.
+     * In case of multiple inheritance this function may change the contents of cptr.
+     * \param cptr a pointer to a pointer to the instance of type \p type
+     * \param type type of *cptr
+     * \warning This function is slow, use it only as last resort.
+     */
+    SbkObjectType* resolveType(void** cptr, SbkObjectType* type);
 
     std::set<SbkObject*> getAllPyObjects();