void ScrollingTree::updateTreeFromStateNode(const ScrollingStateNode* stateNode)
{
if (!stateNode) {
m_nodeMap.clear();
m_rootNode = nullptr;
return;
}
// This fuction recurses through the ScrollingStateTree and updates the corresponding ScrollingTreeNodes.
// Find the ScrollingTreeNode associated with the current stateNode using the shared ID and our HashMap.
ScrollingTreeNodeMap::const_iterator it = m_nodeMap.find(stateNode->scrollingNodeID());
ScrollingTreeNode* node;
if (it != m_nodeMap.end()) {
node = it->value;
node->updateBeforeChildren(*stateNode);
} else {
// If the node isn't found, it's either new and needs to be added to the tree, or there is a new ID for our
// root node.
ScrollingNodeID nodeID = stateNode->scrollingNodeID();
if (!stateNode->parent()) {
// This is the root node. Nuke the node map.
m_nodeMap.clear();
m_rootNode = static_pointer_cast<ScrollingTreeScrollingNode>(createNode(FrameScrollingNode, nodeID));
m_nodeMap.set(nodeID, m_rootNode.get());
m_rootNode->updateBeforeChildren(*stateNode);
node = m_rootNode.get();
} else {
OwnPtr<ScrollingTreeNode> newNode = createNode(stateNode->nodeType(), nodeID);
node = newNode.get();
m_nodeMap.set(nodeID, node);
ScrollingTreeNodeMap::const_iterator it = m_nodeMap.find(stateNode->parent()->scrollingNodeID());
ASSERT(it != m_nodeMap.end());
if (it != m_nodeMap.end()) {
ScrollingTreeNode* parent = it->value;
newNode->setParent(parent);
parent->appendChild(newNode.release());
}
node->updateBeforeChildren(*stateNode);
}
}
// Now update the children if we have any.
Vector<OwnPtr<ScrollingStateNode>>* stateNodeChildren = stateNode->children();
if (stateNodeChildren) {
size_t size = stateNodeChildren->size();
for (size_t i = 0; i < size; ++i)
updateTreeFromStateNode(stateNodeChildren->at(i).get());
}
node->updateAfterChildren(*stateNode);
}
