fn diffs_to_print>()

in src/main.rs [457:503]

• 39 lines of code
• 2 McCabe index (conditional complexity)

    fn diffs_to_print<'a>(&self, orig: &'a str, edit: &'a str) -> Vec<DiffResult<&'a str>> {
        let mut diffs = diff::lines(orig, edit);
        fn is_same(x: &DiffResult<&str>) -> bool {
            match x {
                DiffResult::Both(..) => true,
                _ => false,
            }
        }
        let lines_to_print = match terminal::size() {
            Some((_w, h)) => h,
            None => 25,
        } - 20;

        let num_prefix_lines = diffs.iter().take_while(|diff| is_same(diff)).count();
        let num_suffix_lines = diffs.iter().rev().take_while(|diff| is_same(diff)).count();

        // If the prefix is the length of the diff then the file matched <regex>
        // but applying <subst> didn't result in any changes, there are no diffs
        // to print so we return an empty Vec.
        if diffs.len() == num_prefix_lines {
            return vec![];
        }

        let size_of_diff = diffs.len() - num_prefix_lines - num_suffix_lines;
        let size_of_context = lines_to_print.saturating_sub(size_of_diff);
        let size_of_up_context = size_of_context / 2;
        let size_of_down_context = size_of_context / 2 + size_of_context % 2;

        let start_offset = num_prefix_lines.saturating_sub(size_of_up_context);
        let end_offset = min(
            diffs.len(),
            num_prefix_lines + size_of_diff + size_of_down_context,
        );

        diffs.truncate(end_offset);
        diffs.splice(..start_offset, iter::empty());

        assert!(
            diffs.len() <= max(lines_to_print, size_of_diff),
            "changeset too long: {} > max({}, {})",
            diffs.len(),
            lines_to_print,
            size_of_diff
        );

        diffs
    }