public static DirectiveSpan BuildConditionalDirectiveTree(CompilationUnitSyntax compilationUnit)
{
var root = new DirectiveSpan(0) { End = compilationUnit.Span.End };
var directiveStack = new Stack<DirectiveSpan>();
directiveStack.Push(root);
for (var directiveTrivia = compilationUnit.GetFirstDirective(); directiveTrivia != null; directiveTrivia = directiveTrivia.GetNextDirective())
{
DirectiveSpan previousDirectiveSpan;
DirectiveSpan newDirectiveSpan;
switch (directiveTrivia.Kind())
{
case SyntaxKind.IfDirectiveTrivia:
newDirectiveSpan = directiveStack.Peek().AddChild(directiveTrivia.SpanStart);
directiveStack.Push(newDirectiveSpan);
break;
case SyntaxKind.ElifDirectiveTrivia:
case SyntaxKind.ElseDirectiveTrivia:
previousDirectiveSpan = directiveStack.Pop();
previousDirectiveSpan.End = directiveTrivia.SpanStart;
newDirectiveSpan = directiveStack.Peek().AddChild(directiveTrivia.SpanStart);
directiveStack.Push(newDirectiveSpan);
break;
case SyntaxKind.EndIfDirectiveTrivia:
previousDirectiveSpan = directiveStack.Pop();
previousDirectiveSpan.End = directiveTrivia.SpanStart;
break;
default:
// ignore all other directive trivia
break;
}
}
// cleanup the stack if for some reason the tree of directives has not reached closure.
while (directiveStack.Count > 1)
{
var directiveSpan = directiveStack.Pop();
directiveSpan.End = compilationUnit.Span.End;
}
return root;
}
