private void ContinueIndexingAtChild(
int itemId,
byte fieldId,
IReadOnlyList <TokenLocation> locations,
ReadOnlyMemory <char> remainingTokenText,
int remainingTextSplitPosition)
{
var indexChar = remainingTokenText.Span[remainingTextSplitPosition];
this.EnsureMutatedChildNodesCreated();
if (!this.MutatedChildNodes !.TryGetValue(indexChar, out var childNode))
{
if (this.original != null && this.original.ChildNodes.TryGetValue(indexChar, out var originalChildNode))
{
// the original had an unmutated child node that matched the index character - mutate it now
childNode = new IndexNodeMutation(this.depth + 1, originalChildNode, this.indexNodeFactory);
}
else
{
// This is a novel branch in the index
childNode = new IndexNodeMutation(this);
}
// Track the mutated node
this.MutatedChildNodes.Add(indexChar, childNode);
}
childNode.Index(itemId, fieldId, locations, remainingTokenText.Slice(remainingTextSplitPosition + 1));
}
private bool TryRemove(IndexNode node, int itemId, int nodeDepth, [NotNullWhen(true)] out IndexNodeMutation?mutatedNode)
{
mutatedNode = null;
if (node.HasChildNodes)
{
// Work through the child nodes and recursively determine whether removals are needed from
// them. If they are, then this instance will also become mutated.
foreach (var child in node.ChildNodes)
{
if (this.TryRemove(child.Value, itemId, nodeDepth + 1, out var mutatedChild))
{
if (mutatedNode == null)
{
mutatedNode = new IndexNodeMutation(nodeDepth, node, this.indexNodeFactory);
mutatedNode.EnsureMutatedChildNodesCreated();
}
mutatedNode.MutatedChildNodes !.Add(child.Key, mutatedChild);
}
}
}
if (node.HasMatches)
{
// Removing an item from the nodes current matches will return the same dictionary
// if the item didn't exist - this removes the need for an extra Exists check
var mutatedMatches = node.Matches.Remove(itemId);
if (mutatedMatches != node.Matches)
{
if (mutatedNode == null)
{
mutatedNode = new IndexNodeMutation(nodeDepth, node, this.indexNodeFactory);
}
mutatedNode.EnsureMutatedMatchesCreated();
mutatedNode.MutatedMatches !.Remove(itemId);
}
}
return(mutatedNode != null);
}
private IndexNodeMutation(IndexNodeMutation parent)
: this(parent.depth + 1, parent.indexNodeFactory)
{
}
public IndexMutation(IndexNode root, IIndexNodeFactory indexNodeFactory)
{
this.root = new IndexNodeMutation(0, root, indexNodeFactory);
}
