pub enum Entry<'a, T>where
T: 'a,{
Occupied(OccupiedEntry<'a, T>),
Vacant(VacantEntry<'a, T>),
}
Expand description
A view into a single location in a HeaderMap
, which may be vacant or occupied.
Variants§
Implementations§
source§impl<'a, T> Entry<'a, T>
impl<'a, T> Entry<'a, T>
sourcepub fn or_insert(self, default: T) -> &'a mut T
pub fn or_insert(self, default: T) -> &'a mut T
Ensures a value is in the entry by inserting the default if empty.
Returns a mutable reference to the first value in the entry.
Examples
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);
sourcepub fn or_insert_with<F>(self, default: F) -> &'a mut Twhere
F: FnOnce() -> T,
pub fn or_insert_with<F>(self, default: F) -> &'a mut Twhere
F: FnOnce() -> T,
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.
Examples
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");
sourcepub fn key(&self) -> &HeaderName
pub fn key(&self) -> &HeaderName
Returns a reference to the entry’s key
Examples
let mut map = HeaderMap::new();
assert_eq!(map.entry("x-hello").unwrap().key(), "x-hello");
Trait Implementations§
Auto Trait Implementations§
impl<'a, T> RefUnwindSafe for Entry<'a, T>where
T: RefUnwindSafe,
impl<'a, T> Send for Entry<'a, T>where
T: Send,
impl<'a, T> Sync for Entry<'a, T>where
T: Sync,
impl<'a, T> Unpin for Entry<'a, T>
impl<'a, T> !UnwindSafe for Entry<'a, T>
Blanket Implementations§
source§impl<T> IntoSql for T
impl<T> IntoSql for T
source§fn into_sql<T>(self) -> Self::Expressionwhere
Self: AsExpression<T> + Sized,
fn into_sql<T>(self) -> Self::Expressionwhere
Self: AsExpression<T> + Sized,
Convert
self
to an expression for Diesel’s query builder. Read moresource§fn as_sql<'a, T>(&'a self) -> <&'a Self as AsExpression<T>>::Expressionwhere
&'a Self: AsExpression<T>,
fn as_sql<'a, T>(&'a self) -> <&'a Self as AsExpression<T>>::Expressionwhere
&'a Self: AsExpression<T>,
Convert
&self
to an expression for Diesel’s query builder. Read more