public static SyntaxNode FindNode(
this SyntaxNode node,
int position,
Func <SyntaxNode, bool> descendIntoChildren = null)
{
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
int offset = position;
bool searchChildren = true;
while (searchChildren)
{
if (descendIntoChildren?.Invoke(node) == false)
{
break;
}
// set to false, so loop will only continue if explicitly
// specified in a later stage
searchChildren = false;
int index;
node.GetIndexAndOffset(offset, out index, out offset);
if (index > 0)
{
index--;
}
var slotCount = node.GetSlotCountIncludingTrivia();
for (int i = index; i < slotCount; i++)
{
var child = node.GetSlotIncludingTrivia(i);
if (child != null)
{
if (child.Start > position)
{
// child is after position
break;
}
else if ((child.Start + child.FullWidth) <= position)
{
// child ends before position, go to next child
continue;
}
else
{
node = child;
searchChildren = true;
break;
}
}
}
}
return(node);
}
private static int ComputeFullWidthIterative(SyntaxNode node, int start = 0)
{
if (node.fullWidth >= 0)
{
return(node.fullWidth);
}
node.Start = start;
Stack <ComputeFullWidthState> nodes = new Stack <ComputeFullWidthState>();
nodes.Push(new ComputeFullWidthState()
{
Node = node
});
while (nodes.Count != 0)
{
var state = nodes.Pop();
AfterPopState:
node = state.Node;
if (node.fullWidth == -1)
{
node.fullWidth = node.GetTextWidth();
// Node full width is now zero or the node is a token/trivial
// and the full width represents the width of the text
// for the token/trivia. Therefore, start is only incremented
// for tokens and trivia.
start += node.fullWidth;
}
var parent = state.Parent;
var slotCount = node.GetSlotCountIncludingTrivia();
for (; state.Index < slotCount; state.Index++)
{
var child = node.GetSlotIncludingTrivia(state.Index);
if (child == null)
{
continue;
}
child.Parent = node;
child.Start = start;
if (child.fullWidth == -1)
{
state.Index++;
nodes.Push(state);
state = new ComputeFullWidthState()
{
Node = child,
Parent = node
};
goto AfterPopState;
}
else
{
start += child.fullWidth;
node.fullWidth += child.fullWidth;
}
}
if (parent != null)
{
if (parent.fullWidth == -1)
{
parent.fullWidth = 0;
}
parent.fullWidth += node.fullWidth;
}
}
return(node.fullWidth);
}
