private static Matching ComputeMatching(SyntaxNode target, SyntaxNode source)
{
var groups = source.GetSubtrees().GroupBy(t => t.treeHash);
var sourceTable = new MultiValueDict <int, SyntaxNode>(groups);
var matching = new Matching();
foreach (var tree in target.GetSubtrees())
{
foreach (var t in sourceTable.GetValues(tree.treeHash)) // `tree.hash = t.hash`
{
if (matching.ContainsValue(tree, t)) // Tree `t` has been visited before.
{
continue;
}
// Let's check if `tree` and `t` are really identical.
if (tree.IdenticalTo(t)) // We find a match!
{
// Since `tree` is identical to `t`, so are their subtrees.
tree.GetSubtrees()
.Zip(t.GetSubtrees(), (t1, t2) => (tree: t1, t: t2))
.ToList()
.ForEach(pair => matching.Add(pair.tree, pair.t));
}
else
{
Log.Debug("Same hash {0} but different trees:", tree.treeHash);
var printer = new IndentPrinter();
tree.PrintTo(printer);
printer.PrintLine("<->");
t.PrintTo(printer);
}
}
}
return(matching);
}