Make removal of bindings explicit

This simplifies the code for further refactoring.

Change-Id: I6bcb5ce397f642242af80ce37dc8bba1fa9bf3f5
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

10 files changed, 67 insertions, 57 deletions

diff --git a/src/qml/debugger/qqmlenginedebugservice.cpp b/src/qml/debugger/qqmlenginedebugservice.cpp
index da01d00f17..6f8a67573c 100644
--- a/src/qml/debugger/qqmlenginedebugservice.cpp
+++ b/src/qml/debugger/qqmlenginedebugservice.cpp
@@ -681,7 +681,7 @@ bool QQmlEngineDebugService::resetBinding(int objectId, const QString &propertyN
             QQmlProperty property(object, propertyName);
             QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(property);
             if (oldBinding) {
-                QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::setBinding(property, 0);
+                QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::removeBinding(property);
                 if (oldBinding)
                     oldBinding->destroy();
             }
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index ba18967150..a1787f67fd 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -66,7 +66,7 @@ static void removeBindingOnProperty(QObject *o, int index)
 {
     int coreIndex;
     int valueTypeIndex = QQmlPropertyData::decodeValueTypePropertyIndex(index, &coreIndex);
-    QQmlAbstractBinding *binding = QQmlPropertyPrivate::setBinding(o, coreIndex, valueTypeIndex, 0);
+    QQmlAbstractBinding *binding = QQmlPropertyPrivate::removeBinding(o, coreIndex, valueTypeIndex);
     if (binding) binding->destroy();
 }
 
@@ -664,7 +664,7 @@ void QQmlObjectCreator::setupBindings(const QBitArray &bindingsToSkip)
             QQmlPropertyPrivate::binding(_bindingTarget, _valueTypeProperty->coreIndex, -1);
 
         if (binding && binding->bindingType() != QQmlAbstractBinding::ValueTypeProxy) {
-            QQmlPropertyPrivate::setBinding(_bindingTarget, _valueTypeProperty->coreIndex, -1, 0);
+            QQmlPropertyPrivate::removeBinding(_bindingTarget, _valueTypeProperty->coreIndex, -1);
             binding->destroy();
         } else if (binding) {
             QQmlValueTypeProxyBinding *proxy =
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index 55f4def6a8..3ab312036b 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -719,30 +719,35 @@ QQmlPropertyPrivate::binding(const QQmlProperty &that)
 */
 QQmlAbstractBinding *
 QQmlPropertyPrivate::setBinding(const QQmlProperty &that,
-                                        QQmlAbstractBinding *newBinding,
-                                        WriteFlags flags)
+                                QQmlAbstractBinding *newBinding,
+                                WriteFlags flags)
 {
+    if (!newBinding)
+        removeBinding(that);
+
     if (!that.d || !that.isProperty() || !that.d->object) {
-        if (newBinding)
-            newBinding->destroy();
+        newBinding->destroy();
         return 0;
     }
 
-    if (newBinding) {
-        // In the case that the new binding is provided, we must target the property it
-        // is associated with.  If we don't do this, retargetBinding() can fail.
-        QObject *object = newBinding->object();
-        int pi = newBinding->propertyIndex();
+    // In the case that the new binding is provided, we must target the property it
+    // is associated with.  If we don't do this, retargetBinding() can fail.
+    QObject *object = newBinding->object();
+    int pi = newBinding->propertyIndex();
 
-        int core;
-        int vt = QQmlPropertyData::decodeValueTypePropertyIndex(pi, &core);
+    int core;
+    int vt = QQmlPropertyData::decodeValueTypePropertyIndex(pi, &core);
 
-        return setBinding(object, core, vt, newBinding, flags);
-    } else {
-        return setBinding(that.d->object, that.d->core.coreIndex,
-                          that.d->core.getValueTypeCoreIndex(),
-                          newBinding, flags);
-    }
+    return setBinding(object, core, vt, newBinding, flags);
+}
+
+QQmlAbstractBinding *QQmlPropertyPrivate::removeBinding(const QQmlProperty &that)
+{
+    if (!that.d || !that.isProperty() || !that.d->object)
+        return 0;
+
+    return removeBinding(that.d->object, that.d->core.coreIndex,
+                         that.d->core.getValueTypeCoreIndex());
 }
 
 QQmlAbstractBinding *
@@ -877,6 +882,11 @@ QQmlPropertyPrivate::setBinding(QObject *object, int coreIndex, int valueTypeInd
     return binding;
 }
 
+QQmlAbstractBinding *QQmlPropertyPrivate::removeBinding(QObject *object, int coreIndex, int valueTypeIndex)
+{
+    return setBinding(object, coreIndex, valueTypeIndex, 0);
+}
+
 QQmlAbstractBinding *
 QQmlPropertyPrivate::setBindingNoEnable(QObject *object, int coreIndex, int valueTypeIndex,
                                                 QQmlAbstractBinding *newBinding)
@@ -1212,9 +1222,8 @@ QQmlPropertyPrivate::writeValueProperty(QObject *object,
 {
     // Remove any existing bindings on this property
     if (!(flags & DontRemoveBinding) && object) {
-        QQmlAbstractBinding *binding = setBinding(object, core.coreIndex,
-                                                          core.getValueTypeCoreIndex(),
-                                                          0, flags);
+        QQmlAbstractBinding *binding = removeBinding(object, core.coreIndex,
+                                                          core.getValueTypeCoreIndex());
         if (binding) binding->destroy();
     }
 
diff --git a/src/qml/qml/qqmlproperty_p.h b/src/qml/qml/qqmlproperty_p.h
index ece168925b..4b51128fef 100644
--- a/src/qml/qml/qqmlproperty_p.h
+++ b/src/qml/qml/qqmlproperty_p.h
@@ -108,6 +108,7 @@ public:
                                                    int valueTypeIndex /* -1 */,
                                                    QQmlAbstractBinding *,
                                                    WriteFlags flags = DontRemoveBinding);
+    static QQmlAbstractBinding *removeBinding(QObject *object, int coreIndex, int valueTypeIndex /* -1 */);
     static QQmlAbstractBinding *setBindingNoEnable(QObject *, int coreIndex,
                                                            int valueTypeIndex /* -1 */,
                                                            QQmlAbstractBinding *);
@@ -132,6 +133,7 @@ public:
     static QQmlAbstractBinding *setBinding(const QQmlProperty &that,
                                                    QQmlAbstractBinding *,
                                                    WriteFlags flags = DontRemoveBinding);
+    static QQmlAbstractBinding *removeBinding(const QQmlProperty &that);
     static QQmlBoundSignalExpression *signalExpression(const QQmlProperty &that);
     static QQmlBoundSignalExpressionPointer setSignalExpression(const QQmlProperty &that,
                                                                 QQmlBoundSignalExpression *);
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index 01b37798f8..12600229a9 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -875,7 +875,7 @@ int QQmlVMEMetaObject::metaCall(QMetaObject::Call c, int _id, void **a)
                     if (flags & QQmlPropertyPrivate::RemoveBindingOnAliasWrite) {
                         QQmlData *targetData = QQmlData::get(target);
                         if (targetData && targetData->hasBindingBit(d->propertyIndex())) {
-                            QQmlAbstractBinding *binding = QQmlPropertyPrivate::setBinding(target, d->propertyIndex(), d->isValueTypeAlias()?d->valueTypeIndex():-1, 0);
+                            QQmlAbstractBinding *binding = QQmlPropertyPrivate::removeBinding(target, d->propertyIndex(), d->isValueTypeAlias() ? d->valueTypeIndex() : -1);
                             if (binding) binding->destroy();
                         }
                     }
diff --git a/src/qml/types/qqmlbind.cpp b/src/qml/types/qqmlbind.cpp
index 7814fa6d56..efa182bf87 100644
--- a/src/qml/types/qqmlbind.cpp
+++ b/src/qml/types/qqmlbind.cpp
@@ -287,8 +287,7 @@ void QQmlBind::eval()
         }
 
         //save any set binding for restoration
-        QQmlAbstractBinding *tmp;
-        tmp = QQmlPropertyPrivate::setBinding(d->prop, 0);
+        QQmlAbstractBinding *tmp = QQmlPropertyPrivate::removeBinding(d->prop);
         if (tmp && d->prevBind)
             tmp->destroy();
         else if (!d->prevBind)
diff --git a/src/quick/items/qquickstateoperations.cpp b/src/quick/items/qquickstateoperations.cpp
index 579919db27..b2b9c75c25 100644
--- a/src/quick/items/qquickstateoperations.cpp
+++ b/src/quick/items/qquickstateoperations.cpp
@@ -1024,31 +1024,31 @@ void QQuickAnchorChanges::execute(Reason reason)
     //reset any anchors that have been specified as "undefined"
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::LeftAnchor) {
         targetPrivate->anchors()->resetLeft();
-        QQmlPropertyPrivate::setBinding(d->leftProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->leftProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::RightAnchor) {
         targetPrivate->anchors()->resetRight();
-        QQmlPropertyPrivate::setBinding(d->rightProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->rightProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::HCenterAnchor) {
         targetPrivate->anchors()->resetHorizontalCenter();
-        QQmlPropertyPrivate::setBinding(d->hCenterProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->hCenterProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::TopAnchor) {
         targetPrivate->anchors()->resetTop();
-        QQmlPropertyPrivate::setBinding(d->topProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->topProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::BottomAnchor) {
         targetPrivate->anchors()->resetBottom();
-        QQmlPropertyPrivate::setBinding(d->bottomProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->bottomProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::VCenterAnchor) {
         targetPrivate->anchors()->resetVerticalCenter();
-        QQmlPropertyPrivate::setBinding(d->vCenterProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->vCenterProp);
     }
     if (d->anchorSet->d_func()->resetAnchors & QQuickAnchors::BaselineAnchor) {
         targetPrivate->anchors()->resetBaseline();
-        QQmlPropertyPrivate::setBinding(d->baselineProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->baselineProp);
     }
 
     //set any anchors that have been specified
@@ -1083,49 +1083,49 @@ void QQuickAnchorChanges::reverse(Reason reason)
     //reset any anchors set by the state
     if (d->leftBinding) {
         targetPrivate->anchors()->resetLeft();
-        QQmlPropertyPrivate::setBinding(d->leftBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->leftBinding->property());
         if (reason == ActualChange) {
             d->leftBinding->destroy(); d->leftBinding = 0;
         }
     }
     if (d->rightBinding) {
         targetPrivate->anchors()->resetRight();
-        QQmlPropertyPrivate::setBinding(d->rightBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->rightBinding->property());
         if (reason == ActualChange) {
             d->rightBinding->destroy(); d->rightBinding = 0;
         }
     }
     if (d->hCenterBinding) {
         targetPrivate->anchors()->resetHorizontalCenter();
-        QQmlPropertyPrivate::setBinding(d->hCenterBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->hCenterBinding->property());
         if (reason == ActualChange) {
             d->hCenterBinding->destroy(); d->hCenterBinding = 0;
         }
     }
     if (d->topBinding) {
         targetPrivate->anchors()->resetTop();
-        QQmlPropertyPrivate::setBinding(d->topBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->topBinding->property());
         if (reason == ActualChange) {
             d->topBinding->destroy(); d->topBinding = 0;
         }
     }
     if (d->bottomBinding) {
         targetPrivate->anchors()->resetBottom();
-        QQmlPropertyPrivate::setBinding(d->bottomBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->bottomBinding->property());
         if (reason == ActualChange) {
             d->bottomBinding->destroy(); d->bottomBinding = 0;
         }
     }
     if (d->vCenterBinding) {
         targetPrivate->anchors()->resetVerticalCenter();
-        QQmlPropertyPrivate::setBinding(d->vCenterBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->vCenterBinding->property());
         if (reason == ActualChange) {
             d->vCenterBinding->destroy(); d->vCenterBinding = 0;
         }
     }
     if (d->baselineBinding) {
         targetPrivate->anchors()->resetBaseline();
-        QQmlPropertyPrivate::setBinding(d->baselineBinding->property(), 0);
+        QQmlPropertyPrivate::removeBinding(d->baselineBinding->property());
         if (reason == ActualChange) {
             d->baselineBinding->destroy(); d->baselineBinding = 0;
         }
@@ -1333,31 +1333,31 @@ void QQuickAnchorChanges::clearBindings()
                                             d->anchorSet->d_func()->usedAnchors;
     if (d->applyOrigLeft || (combined & QQuickAnchors::LeftAnchor)) {
         targetPrivate->anchors()->resetLeft();
-        QQmlPropertyPrivate::setBinding(d->leftProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->leftProp);
     }
     if (d->applyOrigRight || (combined & QQuickAnchors::RightAnchor)) {
         targetPrivate->anchors()->resetRight();
-        QQmlPropertyPrivate::setBinding(d->rightProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->rightProp);
     }
     if (d->applyOrigHCenter || (combined & QQuickAnchors::HCenterAnchor)) {
         targetPrivate->anchors()->resetHorizontalCenter();
-        QQmlPropertyPrivate::setBinding(d->hCenterProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->hCenterProp);
     }
     if (d->applyOrigTop || (combined & QQuickAnchors::TopAnchor)) {
         targetPrivate->anchors()->resetTop();
-        QQmlPropertyPrivate::setBinding(d->topProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->topProp);
     }
     if (d->applyOrigBottom || (combined & QQuickAnchors::BottomAnchor)) {
         targetPrivate->anchors()->resetBottom();
-        QQmlPropertyPrivate::setBinding(d->bottomProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->bottomProp);
     }
     if (d->applyOrigVCenter || (combined & QQuickAnchors::VCenterAnchor)) {
         targetPrivate->anchors()->resetVerticalCenter();
-        QQmlPropertyPrivate::setBinding(d->vCenterProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->vCenterProp);
     }
     if (d->applyOrigBaseline || (combined & QQuickAnchors::BaselineAnchor)) {
         targetPrivate->anchors()->resetBaseline();
-        QQmlPropertyPrivate::setBinding(d->baselineProp, 0);
+        QQmlPropertyPrivate::removeBinding(d->baselineProp);
     }
 }
 
diff --git a/src/quick/util/qquickpropertychanges.cpp b/src/quick/util/qquickpropertychanges.cpp
index 6c333c6b13..b190557c96 100644
--- a/src/quick/util/qquickpropertychanges.cpp
+++ b/src/quick/util/qquickpropertychanges.cpp
@@ -560,7 +560,7 @@ void QQuickPropertyChanges::changeValue(const QString &name, const QVariant &val
             if (state() && state()->isStateActive()) {
                 QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(d->property(name));
                 if (oldBinding) {
-                    QQmlPropertyPrivate::setBinding(d->property(name), 0);
+                    QQmlPropertyPrivate::removeBinding(d->property(name));
                     oldBinding->destroy();
                 }
                 d->property(name).write(value);
@@ -626,7 +626,7 @@ void QQuickPropertyChanges::changeExpression(const QString &name, const QString
             if (state() && state()->isStateActive()) {
                 QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(d->property(name));
                 if (oldBinding) {
-                   QQmlPropertyPrivate::setBinding(d->property(name), 0);
+                   QQmlPropertyPrivate::removeBinding(d->property(name));
                    oldBinding->destroy();
                 }
 
diff --git a/src/quick/util/qquickstate.cpp b/src/quick/util/qquickstate.cpp
index 98d7a76c7e..684b0687c1 100644
--- a/src/quick/util/qquickstate.cpp
+++ b/src/quick/util/qquickstate.cpp
@@ -361,7 +361,7 @@ void QQuickState::cancel()
 void QQuickStateAction::deleteFromBinding()
 {
     if (fromBinding) {
-        QQmlPropertyPrivate::setBinding(property, 0);
+        QQmlPropertyPrivate::removeBinding(property);
         fromBinding->destroy();
         fromBinding = 0;
     }
@@ -437,7 +437,7 @@ bool QQuickState::removeEntryFromRevertList(QObject *target, const QString &name
             if (simpleAction.property().object() == target && simpleAction.property().name() == name) {
                 QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(simpleAction.property());
                 if (oldBinding) {
-                    QQmlPropertyPrivate::setBinding(simpleAction.property(), 0);
+                    QQmlPropertyPrivate::removeBinding(simpleAction.property());
                     oldBinding->destroy();
                 }
 
@@ -475,7 +475,7 @@ void QQuickState::removeAllEntriesFromRevertList(QObject *target)
              if (simpleAction.property().object() == target) {
                  QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(simpleAction.property());
                  if (oldBinding) {
-                     QQmlPropertyPrivate::setBinding(simpleAction.property(), 0);
+                     QQmlPropertyPrivate::removeBinding(simpleAction.property());
                      oldBinding->destroy();
                  }
 
@@ -503,7 +503,7 @@ void QQuickState::addEntriesToRevertList(const QList<QQuickStateAction> &actionL
             if (!action.toBinding.isNull()) {
                 QQmlAbstractBinding *oldBinding = QQmlPropertyPrivate::binding(simpleAction.property());
                 if (oldBinding)
-                    QQmlPropertyPrivate::setBinding(simpleAction.property(), 0);
+                    QQmlPropertyPrivate::removeBinding(simpleAction.property());
                 QQmlPropertyPrivate::setBinding(simpleAction.property(), action.toBinding.data(), QQmlPropertyPrivate::DontRemoveBinding);
             }
 
@@ -664,7 +664,7 @@ void QQuickState::apply(QQuickTransition *trans, QQuickState *revert)
         if (!found) {
             QVariant cur = d->revertList.at(ii).property().read();
             QQmlAbstractBinding *delBinding =
-                QQmlPropertyPrivate::setBinding(d->revertList.at(ii).property(), 0);
+                QQmlPropertyPrivate::removeBinding(d->revertList.at(ii).property());
             if (delBinding)
                 delBinding->destroy();
 
diff --git a/src/quick/util/qquicktransitionmanager.cpp b/src/quick/util/qquicktransitionmanager.cpp
index 832596d9a2..81a3c34dc0 100644
--- a/src/quick/util/qquicktransitionmanager.cpp
+++ b/src/quick/util/qquicktransitionmanager.cpp
@@ -131,7 +131,7 @@ void QQuickTransitionManager::transition(const QList<QQuickStateAction> &list,
         if (action.toBinding)
             d->bindingsList << action;
         if (action.fromBinding)
-            QQmlPropertyPrivate::setBinding(action.property, 0); // Disable current binding
+            QQmlPropertyPrivate::removeBinding(action.property); // Disable current binding
         if (action.event && action.event->changesBindings()) {  //### assume isReversable()?
             d->bindingsList << action;
             action.event->clearBindings();
@@ -192,7 +192,7 @@ void QQuickTransitionManager::transition(const QList<QQuickStateAction> &list,
             }
 
             if (action.toBinding)
-                QQmlPropertyPrivate::setBinding(action.property, 0); // Make sure this is disabled during the transition
+                QQmlPropertyPrivate::removeBinding(action.property); // Make sure this is disabled during the transition
 
             QQmlPropertyPrivate::write(action.property, action.fromValue, QQmlPropertyPrivate::BypassInterceptor | QQmlPropertyPrivate::DontRemoveBinding);
         }
@@ -270,7 +270,7 @@ void QQuickTransitionManager::cancel()
     for(int i = 0; i < d->bindingsList.count(); ++i) {
         QQuickStateAction action = d->bindingsList[i];
         if (!action.toBinding.isNull() && action.deletableToBinding) {
-            QQmlPropertyPrivate::setBinding(action.property, 0);
+            QQmlPropertyPrivate::removeBinding(action.property);
             action.toBinding.data()->destroy();
             action.toBinding.clear();
             action.deletableToBinding = false;