YGNode *YogaLayoutableShadowNode::yogaNodeCloneCallbackConnector(YGNode *oldYogaNode, YGNode *parentYogaNode, int childIndex) {
// We have only raw pointer to the parent shadow node, but that's enough for now.
YogaLayoutableShadowNode *parentShadowNodeRawPtr = (YogaLayoutableShadowNode *)parentYogaNode->getContext();
assert(parentShadowNodeRawPtr);
// Old child shadow node already exists but we have only raw pointer to it...
YogaLayoutableShadowNode *oldShadowNodeRawPtr = (YogaLayoutableShadowNode *)oldYogaNode->getContext();
assert(oldShadowNodeRawPtr);
// ... but we have to address this by `shared_ptr`. We cannot create a new `shared_ptr` for it because we will end up with two shared pointers to
// single object which will cause preluminary destroyng the object.
auto &&layoutableChildNodes = parentShadowNodeRawPtr->getLayoutableChildNodes();
SharedLayoutableShadowNode oldShadowNode = nullptr;
// We cannot rely on `childIndex` all the time because `childNodes` can
// contain non-layoutable shadow nodes, however chances are good that
// `childIndex` points to the right shadow node.
// Optimistic attempt (in case if `childIndex` is valid):
if (childIndex < layoutableChildNodes.size()) {
oldShadowNode = layoutableChildNodes[childIndex];
if (oldShadowNode.get() == oldShadowNodeRawPtr) {
goto found;
} else {
oldShadowNode = nullptr;
}
}
// General solution:
for (auto child : layoutableChildNodes) {
if (child.get() == oldShadowNodeRawPtr) {
oldShadowNode = child;
break;
}
}
assert(oldShadowNode);
found:
// The new one does not exist yet. So, we have to clone and replace this using `cloneAndReplaceChild`.
SharedYogaLayoutableShadowNode newShadowNode =
std::dynamic_pointer_cast<const YogaLayoutableShadowNode>(parentShadowNodeRawPtr->cloneAndReplaceChild(oldShadowNode));
assert(newShadowNode);
return &newShadowNode->yogaNode_;
}
