fn compare_components()

in sgx_tstd/src/path.rs [996:1026]

• 27 lines of code
• 9 McCabe index (conditional complexity)

fn compare_components(mut left: Components<'_>, mut right: Components<'_>) -> cmp::Ordering {
    // Fast path for long shared prefixes
    //
    // - compare raw bytes to find first mismatch
    // - backtrack to find separator before mismatch to avoid ambiguous parsings of '.' or '..' characters
    // - if found update state to only do a component-wise comparison on the remainder,
    //   otherwise do it on the full path
    //
    // The fast path isn't taken for paths with a PrefixComponent to avoid backtracking into
    // the middle of one
    if left.prefix.is_none() && right.prefix.is_none() && left.front == right.front {
        // possible future improvement: a [u8]::first_mismatch simd implementation
        let first_difference = match left.path.iter().zip(right.path).position(|(&a, &b)| a != b) {
            None if left.path.len() == right.path.len() => return cmp::Ordering::Equal,
            None => left.path.len().min(right.path.len()),
            Some(diff) => diff,
        };

        if let Some(previous_sep) =
            left.path[..first_difference].iter().rposition(|&b| left.is_sep_byte(b))
        {
            let mismatched_component_start = previous_sep + 1;
            left.path = &left.path[mismatched_component_start..];
            left.front = State::Body;
            right.path = &right.path[mismatched_component_start..];
            right.front = State::Body;
        }
    }

    Iterator::cmp(left, right)
}