1 files changed, 26 insertions, 4 deletions
diff --git a/src/qml/qml/qqmlabstractbinding_p.h b/src/qml/qml/qqmlabstractbinding_p.h
index ae92077add..1ce0a23149 100644
--- a/src/qml/qml/qqmlabstractbinding_p.h
+++ b/src/qml/qml/qqmlabstractbinding_p.h
@@ -63,8 +63,24 @@ QT_BEGIN_NAMESPACE
 class Q_QML_PRIVATE_EXPORT QQmlAbstractBinding
 {
 public:
+    enum DestroyMode {
+
+        // The binding should disconnect itself upon destroy
+        DisconnectBinding,
+
+        // The binding doesn't need to disconnect itself, but it can if it wants to.
+        //
+        // This is used in QQmlData::destroyed() - at the point at which the bindings are
+        // destroyed, the notifiers are already disconnected, so no need to disconnect each
+        // binding again.
+        //
+        // Bindings can use this flag to speed up destruction, especially for v4 bindings
+        // disconnecting a single binding might be slow.
+        KeepBindingConnected
+    };
+
     struct VTable {
-        void (*destroy)(QQmlAbstractBinding *);
+        void (*destroy)(QQmlAbstractBinding *, DestroyMode destroyMode);
         QString (*expression)(const QQmlAbstractBinding *);
         int (*propertyIndex)(const QQmlAbstractBinding *);
         QObject *(*object)(const QQmlAbstractBinding *);
@@ -82,7 +98,9 @@ public:
     // Bindings are free to implement their own memory management, so the delete operator is
     // not necessarily safe.  The default implementation clears the binding, removes it from
     // the object and calls delete.
-    void destroy() { vtable()->destroy(this); }
+    void destroy(DestroyMode destroyMode = DisconnectBinding)
+    { vtable()->destroy(this, destroyMode); }
+
     QString expression() const { return vtable()->expression(this); }
 
     // Should return the encoded property index for the binding.  Should return this value
@@ -108,7 +126,7 @@ public:
 
     // Default implementation for some VTable functions
     template<typename T>
-    static void default_destroy(QQmlAbstractBinding *);
+    static void default_destroy(QQmlAbstractBinding *, DestroyMode);
     static QString default_expression(const QQmlAbstractBinding *);
     static void default_retargetBinding(QQmlAbstractBinding *, QObject *, int);
 
@@ -182,8 +200,12 @@ QQmlAbstractBinding::BindingType QQmlAbstractBinding::bindingType() const
 }
 
 template<typename T>
-void QQmlAbstractBinding::default_destroy(QQmlAbstractBinding *This)
+void QQmlAbstractBinding::default_destroy(QQmlAbstractBinding *This, DestroyMode mode)
 {
+    // Assume the binding disconnects itself in the destructor, which for example QQmlBinding
+    // does in the destructor of its base class, QQmlJavaScriptExpression
+    Q_UNUSED(mode);
+
     This->removeFromObject();
     This->clear();
     delete static_cast<T *>(This);