Find tree sitter node enclosing range, could be used in zed-industries/refactor

gist.rs

// Look up a TreeSitter node based on a range from SCIP.
pub fn find_node<'a>(
    start_node: tree_sitter::Node<'a>,
    range: &Range<tree_sitter::Point>,
) -> Result<tree_sitter::Node<'a>> {
    let mut cursor = start_node.walk();
    // Descend to the first leaf that touches the start of the range, and if the range is
    // non-empty, extends beyond the start.
    while cursor.goto_first_child_for_point(range.start).is_some() {
        if !range.is_empty() && cursor.node().end_position() == range.start {
            cursor.goto_next_sibling();
        }
    }

    // Ascend to the smallest ancestor that strictly contains the range.
    loop {
        let node = cursor.node();
        let node_range = node.range();
        if node_range.start_point <= range.start && node_range.end_point >= range.end {
            if node_range.start_point == range.start && node_range.end_point == range.end {
                return Ok(node);
            } else {
                return Err(anyhow::anyhow!(
                    "Mismatch between SCIP index and TreeSitter parse. \
                    Expected to find node at {}-{}, but containing ancestor is {}-{}.",
                    range.start,
                    range.end,
                    node_range.start_point,
                    node_range.end_point,
                ));
            }
        }
        if !cursor.goto_parent() {
            return Err(anyhow::anyhow!(
                "Mismatch between SCIP index and TreeSitter parse. \
                Expected to find node at {}-{}, but ran out of ancestor nodes.",
                range.start,
                range.end,
            ));
        }
    }
}