You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: diff.rs
    path of file: ./repos/bat/src
    
    the code of the file until where you have to start completion: #![cfg(feature = "git")]

use std::collections::HashMap;
use s
    
pub fn get_git_diff(filename: &Path) -> Option<LineChanges> {
    let repo = Repository::discover(filename).ok()?;

    let repo_path_absolute = fs::canonicalize(repo.workdir()?).ok()?;

    let filepath_absolute = fs::canonicalize(filename).ok()?;
    let filepath_relative_to_repo = filepath_absolute.strip_prefix(&repo_path_absolute).ok()?;

    let mut diff_options = DiffOptions::new();
    let pathspec = filepath_relative_to_repo.into_c_string().ok()?;
    diff_options.pathspec(pathspec);
    diff_options.context_lines(0);

    let diff = repo
        .diff_index_to_workdir(None, Some(&mut diff_options))
        .ok()?;

    let mut line_changes: LineChanges = HashMap::new();

    let mark_section =
        |line_changes: &mut LineChanges, start: u32, end: i32, change: LineChange| {
            for line in start..=end as u32 {
                line_changes.insert(line, change);
            }
        };

    let _ = diff.foreach(
        &mut |_, _| true,
        None,
        Some(&mut |delta, hunk| {
            let path = delta.new_file().path().unwrap_or_else(|| Path::new(""));

            if filepath_relative_to_repo != path {
                return false;
            }

            let old_lines = hunk.old_lines();
            let new_start = hunk.new_start();
            let new_lines = hunk.new_lines();
            let new_end = (new_start + new_lines) as i32 - 1;

            if old_lines == 0 && new_lines > 0 {
                mark_section(&mut line_changes, new_start, new_end, LineChange::Added);
            } else if new_lines == 0 && old_lines > 0 {
                if new_start == 0 {
                    mark_section(&mut line_changes, 1, 1, LineChange::RemovedAbove);
                } else {
                    mark_section(
                        &mut line_changes,
                        new_start,
                        new_start as i32,
                        LineChange::RemovedBelow,
                    );
                }
            } else {
                mark_section(&mut line_changes, new_start, new_end, LineChange::Modified);
            }

            true
        }),
        None,
    );

    Some(line_changes)
}