private SyntaxNode RewriteNode(SyntaxNode node)
{
if (node.IsToken)
{
// Tokens don't have children.
return(node);
}
_startTagTracker.Clear();
var children = node.ChildNodes().ToList();
var rewrittenChildren = new List <SyntaxNode>(children.Count);
for (var i = 0; i < children.Count; i++)
{
var child = children[i];
if (!(child is MarkupTagBlockSyntax tagBlock))
{
TrackChild(child, rewrittenChildren);
continue;
}
var tagName = tagBlock.GetTagName();
if (string.IsNullOrWhiteSpace(tagName) || tagBlock.IsSelfClosing())
{
// Don't want to track incomplete, invalid (Eg. </>, < >), void or self-closing tags.
// Simply wrap it in a block with no body or start/end tag.
if (IsEndTag(tagBlock))
{
// This is an error case.
BuildMarkupElement(rewrittenChildren, startTag: null, tagChildren: new List <RazorSyntaxNode>(), endTag: tagBlock);
}
else
{
BuildMarkupElement(rewrittenChildren, startTag: tagBlock, tagChildren: new List <RazorSyntaxNode>(), endTag: null);
}
}
else if (IsEndTag(tagBlock))
{
if (string.Equals(CurrentStartTagName, tagName, StringComparison.OrdinalIgnoreCase))
{
var startTagTracker = _startTagTracker.Pop();
var startTag = startTagTracker.TagBlock;
// Get the nodes between the start and the end tag.
var tagChildren = startTagTracker.Children;
BuildMarkupElement(rewrittenChildren, startTag, tagChildren, endTag: tagBlock);
}
else
{
// Current tag scope does not match the end tag. Attempt to recover the start tag
// by looking up the previous tag scopes for a matching start tag.
if (!TryRecoverStartTag(rewrittenChildren, tagName, tagBlock))
{
// Could not recover. The end tag doesn't have a corresponding start tag. Wrap it in a block and move on.
var rewritten = SyntaxFactory.MarkupElement(startTag: null, body: new SyntaxList <RazorSyntaxNode>(), endTag: tagBlock);
TrackChild(rewritten, rewrittenChildren);
}
}
}
else
{
// This is a start tag. Keep track of it.
_startTagTracker.Push(new TagBlockTracker(tagBlock));
}
}
while (_startTagTracker.Count > 0)
{
// We reached the end of the list and still have unmatched start tags
var startTagTracker = _startTagTracker.Pop();
var startTag = startTagTracker.TagBlock;
var tagChildren = startTagTracker.Children;
BuildMarkupElement(rewrittenChildren, startTag, tagChildren, endTag: null);
}
// We now have finished building our list of rewritten Children.
// At this point, We should have a one to one replacement for every child. The replacement can be null.
Debug.Assert(children.Count == rewrittenChildren.Count);
node = node.ReplaceNodes(children, (original, rewritten) =>
{
var originalIndex = children.IndexOf(original);
if (originalIndex != -1)
{
// If this returns null, that node will be removed.
return(rewrittenChildren[originalIndex]);
}
return(original);
});
return(node);
}
