Allow canceling incubation

Qt Quick Controls must avoid destroying any object that belongs to
a tree of objects being incubated. The problem is that QQC have no
control over the incubation process. This patch adds private API
that allows QQC to cancel incubation of a specific item that QQC
would like to destroy.

Change-Id: Id9f9004736e2b53fe46cdb6bb3055b7457def94d
Task-number: QTBUG-50992
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 09936f6e7a..38a16b8cde 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -1270,6 +1270,21 @@ QQmlContextData *QQmlObjectCreator::finalize(QQmlInstantiationInterrupt &interru
     return sharedState->rootContext;
 }
 
+void QQmlObjectCreator::cancel(QObject *object)
+{
+    int last = sharedState->allCreatedObjects.count() - 1;
+    int i = last;
+    while (i >= 0) {
+        if (sharedState->allCreatedObjects.at(i) == object) {
+            if (i < last)
+                qSwap(sharedState->allCreatedObjects[i], sharedState->allCreatedObjects[last]);
+            sharedState->allCreatedObjects.pop();
+            break;
+        }
+        --i;
+    }
+}
+
 void QQmlObjectCreator::clear()
 {
     if (phase == Done || phase == Finalizing || phase == Startup)