void YGNode::cloneChildrenIfNeeded() {
// YGNodeRemoveChild in yoga.cpp has a forked variant of this algorithm
// optimized for deletions.
const uint32_t childCount = static_cast<uint32_t>(children_.size());
if (childCount == 0) {
// This is an empty set. Nothing to clone.
return;
}
const YGNodeRef firstChild = children_.front();
if (firstChild->getParent() == this) {
// If the first child has this node as its parent, we assume that it is
// already unique. We can do this because if we have it has a child, that
// means that its parent was at some point cloned which made that subtree
// immutable. We also assume that all its sibling are cloned as well.
return;
}
const YGNodeClonedFunc cloneNodeCallback = config_->cloneNodeCallback;
for (uint32_t i = 0; i < childCount; ++i) {
const YGNodeRef oldChild = children_[i];
const YGNodeRef newChild = YGNodeClone(oldChild);
replaceChild(newChild, i);
newChild->setParent(this);
if (cloneNodeCallback) {
cloneNodeCallback(oldChild, newChild, this, i);
}
}
}
YGNodeRef YGConfig::cloneNode(
YGNodeRef node,
YGNodeRef owner,
int childIndex,
void* cloneContext) {
YGNodeRef clone = nullptr;
if (cloneNodeCallback_.noContext != nullptr) {
clone = cloneNodeUsesContext_
? cloneNodeCallback_.withContext(node, owner, childIndex, cloneContext)
: cloneNodeCallback_.noContext(node, owner, childIndex);
}
if (clone == nullptr) {
clone = YGNodeClone(node);
}
return clone;
}
