QPropertyBindingPrivate: Support QQmlProperyBinding

QQmlProperyBinding needs the ability to suspend binding evaluation, and
needs access to the propertyDataPtr.

Change-Id: If82079ffdf28fb277c6e5083714c28478f6e1729
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

src/corelib/kernel/qproperty.cpp

@@ -1697,6 +1697,7 @@ QPropertyBindingData *QBindingStorage::bindingData_helper(QUntypedPropertyData *
 }
 
 
+namespace QtPrivate {
 BindingEvaluationState *suspendCurrentBindingStatus()
 {
     auto ret = bindingStatus.currentlyEvaluatingBinding;
@@ -1709,7 +1710,6 @@ void restoreBindingStatus(BindingEvaluationState *status)
     bindingStatus.currentlyEvaluatingBinding = status;
 }
 
-namespace QtPrivate {
 /*!
     \internal
     This function can be used to detect whether we are currently

src/corelib/kernel/qproperty_p.h

@@ -193,6 +193,7 @@ private:
     QPropertyObserverPointer firstObserver; // list of observers observing us
     QScopedPointer<std::vector<QPropertyObserver>> heapObservers; // for things we are observing
 
+protected:
     QUntypedPropertyData *propertyDataPtr = nullptr;
 
     /* For bindings set up from C++, location stores where the binding was created in the C++ source
@@ -203,7 +204,6 @@ private:
     */
     static_assert(std::is_trivially_destructible_v<QPropertyBindingSourceLocation>);
     static_assert(std::is_trivially_destructible_v<std::byte[sizeof(QPropertyBindingSourceLocation)]>);
-protected:
     using DeclarativeErrorCallback = void(*)(QPropertyBindingPrivate *);
     union {
         QPropertyBindingSourceLocation location;
@@ -353,6 +353,7 @@ public:
             delete[] reinterpret_cast<std::byte *>(priv);
         }
     }
+
 private:
     bool evaluateIfDirtyAndReturnTrueIfValueChanged_helper(const QUntypedPropertyData *data, QBindingStatus *status = nullptr);
 };
@@ -584,6 +585,11 @@ private:
             QObjectCompatProperty<Class, Type, Class::_qt_property_##name##_offset, setter>(       \
                     value);
 
+namespace QtPrivate {
+Q_CORE_EXPORT BindingEvaluationState *suspendCurrentBindingStatus();
+Q_CORE_EXPORT void restoreBindingStatus(BindingEvaluationState *status);
+}
+
 QT_END_NAMESPACE
 
 #endif // QPROPERTY_P_H

src/corelib/kernel/qpropertyprivate.h

@@ -69,6 +69,7 @@ struct RefCounted {
 };
 }
 
+class QQmlPropertyBinding;
 class QPropertyBindingPrivate;
 class QPropertyBindingPrivatePtr
 {
@@ -223,6 +224,7 @@ class Q_CORE_EXPORT QPropertyBindingData
     // notification later when the value changes.
     mutable quintptr d_ptr = 0;
     friend struct QT_PREPEND_NAMESPACE(QPropertyBindingDataPointer);
+    friend class QT_PREPEND_NAMESPACE(QQmlPropertyBinding);
     Q_DISABLE_COPY(QPropertyBindingData)
 public:
     QPropertyBindingData() = default;