use std::path::{Path, PathBuf};
pub fn relative(path: &Path, base: &Path) -> Option<PathBuf> {
use std::path::Component;
if path.is_absolute() != base.is_absolute() {
if path.is_absolute() {
Some(PathBuf::from(path))
} else {
None
}
} else {
let mut ita = path.components();
let mut itb = base.components();
let mut comps: Vec<Component> = vec![];
loop {
match (ita.next(), itb.next()) {
(None, None) => break,
(Some(a), None) => {
comps.push(a);
comps.extend(ita.by_ref());
break;
}
(None, _) => comps.push(Component::ParentDir),
(Some(a), Some(b)) if comps.is_empty() && a == b => (),
(Some(a), Some(b)) if b == Component::CurDir => comps.push(a),
(Some(_), Some(b)) if b == Component::ParentDir => return None,
(Some(a), Some(_)) => {
comps.push(Component::ParentDir);
for _ in itb {
comps.push(Component::ParentDir);
}
comps.push(a);
comps.extend(ita.by_ref());
break;
}
}
}
Some(comps.iter().map(|c| c.as_os_str()).collect())
}
}