tst_qsharedpointer: don't inherit from QSharedPointer

QSharedPointer is about to be made final. Instead
of inheriting from it to gain access to the
d-pointer, cast it to a layout-compatible struct
and access the pointer from there.

Assert liberally to ensure layout compatibility.

Change-Id: Ifc0fa6a6608e861469286673844325663f4f7fcc
Reviewed-by: Thiago Macieira <[email protected]>

1 files changed, 12 insertions, 8 deletions

diff --git a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
index 5b697a35098..f8b9abb359e 100644
--- a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
+++ b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
@@ -114,15 +114,19 @@ public:
     }
 };
 
-template <typename Base>
-class RefCountHack: public Base
+template<typename T> static inline
+QtSharedPointer::ExternalRefCountData *refCountData(const QtSharedPointer::ExternalRefCount<T> &b)
 {
-public:
-    using Base::d;
-};
-template<typename Base> static inline
-QtSharedPointer::ExternalRefCountData *refCountData(const Base &b)
-{ return static_cast<const RefCountHack<Base> *>(&b)->d; }
+    // access d-pointer:
+    struct Dummy {
+        void* value;
+        QtSharedPointer::ExternalRefCountData* data;
+    };
+    // sanity checks:
+    Q_STATIC_ASSERT(sizeof(QtSharedPointer::ExternalRefCount<T>) == sizeof(Dummy));
+    Q_ASSERT(static_cast<const Dummy*>(static_cast<const void*>(&b))->value == b.data());
+    return static_cast<const Dummy*>(static_cast<const void*>(&b))->data;
+}
 
 class Data
 {