// Inc/decs the position ref counts on TextTreeTextNodes as the navigator
// is repositioned.
// If the new ref is to a TextTreeTextNode, the node may be split.
// Returns the actual node referenced, which will always be newNode,
// unless newNode is a TextTreeTextNode that gets split. The caller
// should use the returned node to position navigators.
private TextTreeNode AdjustRefCounts(TextTreeNode newNode, ElementEdge newNodeEdge, TextTreeNode oldNode, ElementEdge oldNodeEdge)
{
TextTreeNode node;
// This test should walk the tree upwards to catch all errors...probably not worth the slowdown though.
Invariant.Assert(oldNode.ParentNode == null || oldNode.IsChildOfNode(oldNode.ParentNode), "Trying to add ref a dead node!");
Invariant.Assert(newNode.ParentNode == null || newNode.IsChildOfNode(newNode.ParentNode), "Trying to add ref a dead node!");
node = newNode;
if (newNode != oldNode || newNodeEdge != oldNodeEdge)
{
node = newNode.IncrementReferenceCount(newNodeEdge);
oldNode.DecrementReferenceCount(oldNodeEdge);
}
return node;
}