1 files changed, 28 insertions, 12 deletions

diff --git a/src/corelib/kernel/qpropertyprivate.h b/src/corelib/kernel/qpropertyprivate.h
index ab69e966cf..86dc08a6bc 100644
--- a/src/corelib/kernel/qpropertyprivate.h
+++ b/src/corelib/kernel/qpropertyprivate.h
@@ -18,6 +18,7 @@
 #include <QtCore/qglobal.h>
 #include <QtCore/qtaggedpointer.h>
 #include <QtCore/qmetatype.h>
+#include <QtCore/qcontainerfwd.h>
 
 #include <functional>
 
@@ -28,13 +29,20 @@ class QBindingStorage;
 template<typename Class, typename T, auto Offset, auto Setter, auto Signal, auto Getter>
 class QObjectCompatProperty;
 
+struct QBindingObserverPtr;
+using PendingBindingObserverList = QVarLengthArray<QBindingObserverPtr>;
+
 namespace QtPrivate {
 // QPropertyBindingPrivatePtr operates on a RefCountingMixin solely so that we can inline
 // the constructor and copy constructor
 struct RefCounted {
+
+    int refCount() const { return ref; }
+    void addRef() { ++ref; }
+    bool deref() { return --ref != 0; }
+
+private:
     int ref = 0;
-    void addRef() {++ref;}
-    bool deref() {--ref; return ref;}
 };
 }
 
@@ -57,7 +65,7 @@ public:
     QPropertyBindingPrivatePtr() noexcept : d(nullptr) { }
     ~QPropertyBindingPrivatePtr()
     {
-        if (d && (--d->ref == 0))
+        if (d && !d->deref())
             destroyAndFreeMemory();
     }
     Q_CORE_EXPORT void destroyAndFreeMemory();
@@ -78,7 +86,7 @@ public:
         reset(o);
         return *this;
     }
-    QPropertyBindingPrivatePtr(QPropertyBindingPrivatePtr &&o) noexcept : d(qExchange(o.d, nullptr)) {}
+    QPropertyBindingPrivatePtr(QPropertyBindingPrivatePtr &&o) noexcept : d(std::exchange(o.d, nullptr)) {}
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QPropertyBindingPrivatePtr)
 
     operator bool () const noexcept { return d != nullptr; }
@@ -115,15 +123,18 @@ private:
 class QUntypedPropertyBinding;
 class QPropertyBindingPrivate;
 struct QPropertyBindingDataPointer;
+class QPropertyObserver;
 struct QPropertyObserverPointer;
 
 class QUntypedPropertyData
 {
-public:
-    // sentinel to check whether a class inherits QUntypedPropertyData
-    struct InheritsQUntypedPropertyData {};
 };
 
+namespace QtPrivate {
+template <typename T>
+using IsUntypedPropertyData = std::enable_if_t<std::is_base_of_v<QUntypedPropertyData, T>, bool>;
+}
+
 template <typename T>
 class QPropertyData;
 
@@ -189,8 +200,7 @@ struct BindingFunctionVTable
                     return true;
                 } else {
                     // Our code will never instantiate this
-                    Q_UNREACHABLE();
-                    return false;
+                    Q_UNREACHABLE_RETURN(false);
                 }
             },
             /*destroy*/[](void *f){ static_cast<Callable *>(f)->~Callable(); },
@@ -299,17 +309,23 @@ private:
     {
         quintptr &d = d_ptr;
         if (isNotificationDelayed())
-            return reinterpret_cast<QPropertyProxyBindingData *>(d_ptr & ~(BindingBit|DelayedNotificationBit))->d_ptr;
+            return proxyData()->d_ptr;
         return d;
     }
     quintptr d() const { return d_ref(); }
+    QPropertyProxyBindingData *proxyData() const
+    {
+        Q_ASSERT(isNotificationDelayed());
+        return reinterpret_cast<QPropertyProxyBindingData *>(d_ptr & ~(BindingBit|DelayedNotificationBit));
+    }
     void registerWithCurrentlyEvaluatingBinding_helper(BindingEvaluationState *currentBinding) const;
     void removeBinding_helper();
 
     enum NotificationResult { Delayed, Evaluated };
     NotificationResult notifyObserver_helper(
-            QUntypedPropertyData *propertyDataPtr, QPropertyObserverPointer observer,
-            QBindingStorage *storage) const;
+            QUntypedPropertyData *propertyDataPtr, QBindingStorage *storage,
+            QPropertyObserverPointer observer,
+            PendingBindingObserverList &bindingObservers) const;
 };
 
 template <typename T, typename Tag>