A view into a single location in a HeaderMap
, which may be vacant or occupied.
Ensures a value is in the entry by inserting the default if empty.
Returns a mutable reference to the first value in the entry.
let mut map: HeaderMap<u32> = HeaderMap::default();
let headers = &[
"content-length",
"x-hello",
"Content-Length",
"x-world",
];
for &header in headers {
let counter = map.entry(header)
.expect("valid header names")
.or_insert(0);
*counter += 1;
}
assert_eq!(map["content-length"], 2);
assert_eq!(map["x-hello"], 1);
Ensures a value is in the entry by inserting the result of the default
function if empty.
The default function is not called if the entry exists in the map.
Returns a mutable reference to the first value in the entry.
Basic usage.
let mut map = HeaderMap::new();
let res = map.entry("x-hello").unwrap()
.or_insert_with(|| "world".parse().unwrap());
assert_eq!(res, "world");
The default function is not called if the entry exists in the map.
let mut map = HeaderMap::new();
map.insert(HOST, "world".parse().unwrap());
let res = map.entry("host")
.expect("host is a valid string")
.or_insert_with(|| unreachable!());
assert_eq!(res, "world");
Returns a reference to the entry's key
let mut map = HeaderMap::new();
assert_eq!(map.entry("x-hello").unwrap().key(), "x-hello");
Formats the value using the given formatter. Read more
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
Immutably borrows from an owned value. Read more
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static
Mutably borrows from an owned value. Read more
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)