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
Occupied(OccupiedEntry<'a, T>)
An occupied entry
Vacant(VacantEntry<'a, T>)
A vacant entry
Implementations
sourceimpl<'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)
.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 T where
F: FnOnce() -> T,
pub fn or_insert_with<F>(self, default: F) -> &'a mut T where
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")
.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")
.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").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
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
sourcefn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more
sourcefn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
sourceimpl<T> WithSubscriber for T
impl<T> WithSubscriber for T
sourcefn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> where
S: Into<Dispatch>,
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
sourcefn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more