private IEnumerable <SyntaxNodeOrToken> DescendantNodesAndTokensIntoTrivia(TextSpan span, Func <SyntaxNode, bool> descendIntoChildren, bool includeSelf)
{
if (includeSelf && IsInSpan(ref span, this.FullSpan))
{
yield return(this);
}
using (var stack = new ThreeEnumeratorListStack(this, descendIntoChildren))
{
while (stack.IsNotEmpty)
{
switch (stack.PeekNext())
{
case ThreeEnumeratorListStack.Which.Node:
SyntaxNodeOrToken value;
if (stack.TryGetNextInSpan(ref span, out value))
{
// PERF: The following code has an unusual structure (note the 'break' out of
// the case statement from inside an if body) in order to convince the compiler
// that it can save a field in the iterator machinery.
if (value.IsNode)
{
// parent nodes come before children (prefix document order)
stack.PushChildren(value.AsNode(), descendIntoChildren);
}
else if (value.IsToken)
{
var token = value.AsToken();
// only look through trivia if this node has structured trivia
if (token.HasStructuredTrivia)
{
// trailing trivia comes last
if (token.HasTrailingTrivia)
{
stack.PushTrailingTrivia(ref token);
}
// tokens come between leading and trailing trivia
stack.PushToken(ref value);
// leading trivia comes first
if (token.HasLeadingTrivia)
{
stack.PushLeadingTrivia(ref token);
}
// Exit the case block without yielding (see PERF note above)
break;
}
// no structure trivia, so just yield this token now
}
// PERF: Yield here (rather than inside the if bodies above) so that it's
// obvious to the compiler that 'value' is not used beyond this point and,
// therefore, doesn't need to be kept in a field.
yield return(value);
}
break;
case ThreeEnumeratorListStack.Which.Trivia:
// yield structure nodes and enumerate their children
SyntaxTrivia trivia;
if (stack.TryGetNext(out trivia))
{
if (trivia.HasStructure && IsInSpan(ref span, trivia.FullSpan))
{
var structureNode = trivia.GetStructure();
// parent nodes come before children (prefix document order)
// PERF: Push before yield return so that "structureNode" is 'dead' after the yield
// and therefore doesn't need to be stored in the iterator state machine. This
// saves a field.
stack.PushChildren(structureNode, descendIntoChildren);
yield return(structureNode);
}
}
break;
case ThreeEnumeratorListStack.Which.Token:
yield return(stack.PopToken());
break;
}
}
}
}
private IEnumerable<SyntaxNodeOrToken> DescendantNodesAndTokensIntoTrivia(TextSpan span, Func<SyntaxNode, bool> descendIntoChildren, bool includeSelf)
{
if (includeSelf && IsInSpan(ref span, this.FullSpan))
{
yield return this;
}
using (var stack = new ThreeEnumeratorListStack(this, descendIntoChildren))
{
while (stack.IsNotEmpty)
{
switch (stack.PeekNext())
{
case ThreeEnumeratorListStack.Which.Node:
SyntaxNodeOrToken value;
if (stack.TryGetNextInSpan(ref span, out value))
{
// PERF: The following code has an unusual structure (note the 'break' out of
// the case statement from inside an if body) in order to convince the compiler
// that it can save a field in the iterator machinery.
if (value.IsNode)
{
// parent nodes come before children (prefix document order)
stack.PushChildren(value.AsNode(), descendIntoChildren);
}
else if (value.IsToken)
{
var token = value.AsToken();
// only look through trivia if this node has structured trivia
if (token.HasStructuredTrivia)
{
// trailing trivia comes last
if (token.HasTrailingTrivia)
{
stack.PushTrailingTrivia(ref token);
}
// tokens come between leading and trailing trivia
stack.PushToken(ref value);
// leading trivia comes first
if (token.HasLeadingTrivia)
{
stack.PushLeadingTrivia(ref token);
}
// Exit the case block without yielding (see PERF note above)
break;
}
// no structure trivia, so just yield this token now
}
// PERF: Yield here (rather than inside the if bodies above) so that it's
// obvious to the compiler that 'value' is not used beyond this point and,
// therefore, doesn't need to be kept in a field.
yield return value;
}
break;
case ThreeEnumeratorListStack.Which.Trivia:
// yield structure nodes and enumerate their children
SyntaxTrivia trivia;
if (stack.TryGetNext(out trivia))
{
if (trivia.HasStructure && IsInSpan(ref span, trivia.FullSpan))
{
var structureNode = trivia.GetStructure();
// parent nodes come before children (prefix document order)
// PERF: Push before yield return so that "structureNode" is 'dead' after the yield
// and therefore doesn't need to be stored in the iterator state machine. This
// saves a field.
stack.PushChildren(structureNode, descendIntoChildren);
yield return structureNode;
}
}
break;
case ThreeEnumeratorListStack.Which.Token:
yield return stack.PopToken();
break;
}
}
}
}
