use crate::header::{Entry, HeaderMap, OccupiedEntry};
pub(crate) fn replace_headers(dst: &mut HeaderMap, src: HeaderMap) {
let mut prev_entry: Option<OccupiedEntry<_>> = None;
for (key, value) in src {
match key {
Some(key) => match dst.entry(key) {
Entry::Occupied(mut e) => {
e.insert(value);
prev_entry = Some(e);
}
Entry::Vacant(e) => {
let e = e.insert_entry(value);
prev_entry = Some(e);
}
},
None => match prev_entry {
Some(ref mut entry) => {
entry.append(value);
}
None => unreachable!("HeaderMap::into_iter yielded None first"),
},
}
}
}