Function hash_call_sequence

src/redundancy.rs:249–280

Pre-order walk, collecting the leftmost identifier of every call/invocation/macro node, in source order, then hashing them.

(root: Node<'_>, source: &[u8])

/// Pre-order walk, collecting the leftmost identifier of every
/// call/invocation/macro node, in source order, then hashing them.
fn hash_call_sequence(root: Node<'_>, source: &[u8]) -> String {
    let mut calls: Vec<String> = Vec::new();
    let mut stack: Vec<Node<'_>> = vec![root];
    while let Some(node) = stack.pop() {
        let kind = node.kind();
        if is_call_kind(kind) {
            if let Some(name) = leftmost_callable_name(node, source) {
                calls.push(name);
            }
        }
        let mut cursor = node.walk();
        if cursor.goto_first_child() {
            let mut children: Vec<Node<'_>> = Vec::new();
            loop {
                children.push(cursor.node());
                if !cursor.goto_next_sibling() {
                    break;
                }
            }
            for child in children.into_iter().rev() {
                stack.push(child);
            }
        }
    }

    let mut hasher = Sha256::new();
    for name in &calls {
        hasher.update(name.as_bytes());
        hasher.update([0x1f]);
    }
    short_hex(hasher.finalize().as_slice())
}

fn is_call_kind(kind: &str) -> bool {
    const MARKERS: [&str; 4] = ["call", "invocation", "macro", "apply"];