Adjust to QPropertyBindingPrivate not using std::function anymore

Change-Id: Id197f3d4bf8ab60256040e0a177d5596ce78a0a8
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 44 insertions, 9 deletions

diff --git a/src/qml/qml/qqmlpropertybinding.cpp b/src/qml/qml/qqmlpropertybinding.cpp
index b691bf39a9..d56d41f834 100644
--- a/src/qml/qml/qqmlpropertybinding.cpp
+++ b/src/qml/qml/qqmlpropertybinding.cpp
@@ -63,12 +63,13 @@ QUntypedPropertyBinding QQmlPropertyBinding::create(const QQmlPropertyData *pd,
             QPropertyBindingSourceLocation());
     }
 
-    auto binding = new QQmlPropertyBinding(QMetaType(pd->propType()));
+    auto buffer = new std::byte[sizeof(QQmlPropertyBinding)]; // QQmlPropertyBinding uses delete[]
+    auto binding = new (buffer) QQmlPropertyBinding(QMetaType(pd->propType()));
     binding->setNotifyOnValueChanged(true);
     binding->setContext(ctxt);
     binding->setScopeObject(obj);
     binding->setupFunction(scope, function);
-    return QUntypedPropertyBinding(QPropertyBindingPrivatePtr(binding).data());
+    return QUntypedPropertyBinding(static_cast<QPropertyBindingPrivate *>(QPropertyBindingPrivatePtr(binding).data()));
 }
 
 void QQmlPropertyBinding::expressionChanged()
@@ -89,15 +90,14 @@ void QQmlPropertyBinding::expressionChanged()
     m_error.setTag(currentTag);
 }
 
-QQmlPropertyBinding::QQmlPropertyBinding(const QMetaType &mt)
+QQmlPropertyBinding::QQmlPropertyBinding(QMetaType mt)
     : QPropertyBindingPrivate(mt,
-                              [this](const QMetaType &metaType, void *dataPtr) -> bool {
-                                  return evaluate(metaType, dataPtr);
-                              }, QPropertyBindingSourceLocation())
+                              &QtPrivate::bindingFunctionVTable<QQmlPropertyBinding>,
+                              QPropertyBindingSourceLocation())
 {
 }
 
-bool QQmlPropertyBinding::evaluate(const QMetaType &metaType, void *dataPtr)
+bool QQmlPropertyBinding::evaluate(QMetaType metaType, void *dataPtr)
 {
     const auto ctxt = context();
     QQmlEngine *engine = ctxt ? ctxt->engine() : nullptr;
diff --git a/src/qml/qml/qqmlpropertybinding_p.h b/src/qml/qml/qqmlpropertybinding_p.h
index c3c684a753..1ea82b26be 100644
--- a/src/qml/qml/qqmlpropertybinding_p.h
+++ b/src/qml/qml/qqmlpropertybinding_p.h
@@ -63,19 +63,54 @@ QT_BEGIN_NAMESPACE
 
 class QQmlPropertyBinding : public QQmlJavaScriptExpression,
                             public QPropertyBindingPrivate
+
 {
 public:
+    static constexpr auto propertyBindingOffset() {
+        QT_WARNING_PUSH QT_WARNING_DISABLE_INVALID_OFFSETOF
+        return offsetof(QQmlPropertyBinding, ref);
+        QT_WARNING_POP
+    }
+
     static QUntypedPropertyBinding create(const QQmlPropertyData *pd, QV4::Function *function,
                                           QObject *obj, const QQmlRefPointer<QQmlContextData> &ctxt,
                                           QV4::ExecutionContext *scope);
 
     void expressionChanged() override;
 
+
+    static bool doEvaluate(QMetaType metaType, QUntypedPropertyData *dataPtr, void *f) {
+        auto address = static_cast<std::byte*>(f);
+        address -= sizeof (QPropertyBindingPrivate); // f now points to QPropertyBindingPrivate suboject
+        address -= QQmlPropertyBinding::propertyBindingOffset(); //  f now points to QQmlPropertyBinding
+        return reinterpret_cast<QQmlPropertyBinding *>(address)->evaluate(metaType, dataPtr);
+    }
+
 private:
-    QQmlPropertyBinding(const QMetaType &metaType);
+    QQmlPropertyBinding(QMetaType metaType);
+
+    bool evaluate(QMetaType metaType, void *dataPtr);
+
+
+};
+
+template <auto I>
+struct Print {};
 
-    bool evaluate(const QMetaType &metaType, void *dataPtr);
+namespace QtPrivate {
+template<>
+inline constexpr BindingFunctionVTable bindingFunctionVTable<QQmlPropertyBinding> = {
+    &QQmlPropertyBinding::doEvaluate,
+    [](void *qpropertyBinding){
+        auto address = static_cast<std::byte*>(qpropertyBinding);
+        address -= QQmlPropertyBinding::propertyBindingOffset(); //  f now points to QQmlPropertyBinding
+        reinterpret_cast<QQmlPropertyBinding *>(address)->~QQmlPropertyBinding();
+        delete[] address;
+    },
+    [](void *, void *){},
+    0
 };
+}
 
 class QQmlTranslationPropertyBinding
 {