Shared node bookkeeping

Any time a property references a QNode there is a risk that the node gets
destroyed and then the property is left pointing to a dangling pointer.

To handle such cases, setters of such properties are able to use a helper
that internally connect QObject::destroyed signal to a setter removal method.

Change-Id: I42428c851d0e3d2d88ab0cf6a5b75605334ec648
Task-number: QTBUG-53456
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/render/framegraph/qrenderstateset.cpp b/src/render/framegraph/qrenderstateset.cpp
index 5d0db339a..845fb5d91 100644
--- a/src/render/framegraph/qrenderstateset.cpp
+++ b/src/render/framegraph/qrenderstateset.cpp
@@ -99,6 +99,9 @@ void QRenderStateSet::addRenderState(QRenderState *state)
     if (!d->m_renderStates.contains(state)) {
         d->m_renderStates.append(state);
 
+        // Ensures proper bookkeeping
+        d->registerDestructionHelper(state, &QRenderStateSet::removeRenderState, d->m_renderStates);
+
         if (!state->parent())
             state->setParent(this);
 
@@ -124,6 +127,8 @@ void QRenderStateSet::removeRenderState(QRenderState *state)
         d->notifyObservers(change);
     }
     d->m_renderStates.removeOne(state);
+    // Remove bookkeeping connection
+    d->unregisterDestructionHelper(state);
 }
 
 /*!