passing a rust function as a C callback

gistfile1.txt

extern fn status_foreach_callback(path: *c_char, stat: c_uint, payload: *c_void) -> c_int unsafe {
    let path_str = str::raw::from_c_str(path);
    let f: *fn(&str, uint) = cast::reinterpret_cast(&payload);

    (*f)(path_str, stat as uint);

    return 0;
}

// ...

impl Repository {
    fn for_status(f: fn(&str, uint)) unsafe {
        c::git_status_foreach(self.c_repository, status_foreach_callback, cast::reinterpret_cast(&ptr::addr_of(&f)));
    }
}