Enum tonic::metadata::Entry [−][src]
pub enum Entry<'a, VE: ValueEncoding> {
Occupied(OccupiedEntry<'a, VE>),
Vacant(VacantEntry<'a, VE>),
}
Expand description
A view into a single location in a MetadataMap
, which may be vacant or
occupied.
Variants
Occupied(OccupiedEntry<'a, VE>)
Tuple Fields
0: OccupiedEntry<'a, VE>
An occupied entry
Vacant(VacantEntry<'a, VE>)
Tuple Fields
0: VacantEntry<'a, VE>
A vacant entry
Implementations
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: MetadataMap = MetadataMap::default();
let keys = &[
"content-length",
"x-hello",
"Content-Length",
"x-world",
];
for &key in keys {
let counter = map.entry(key)
.expect("valid key names")
.or_insert("".parse().unwrap());
*counter = format!("{}{}", counter.to_str().unwrap(), "1").parse().unwrap();
}
assert_eq!(map.get("content-length").unwrap(), "11");
assert_eq!(map.get("x-hello").unwrap(), "1");
pub fn or_insert_with<F: FnOnce() -> MetadataValue<VE>>(
self,
default: F
) -> &'a mut MetadataValue<VE>
pub fn or_insert_with<F: FnOnce() -> MetadataValue<VE>>(
self,
default: F
) -> &'a mut MetadataValue<VE>
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 = MetadataMap::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 = MetadataMap::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
Examples
let mut map = MetadataMap::new();
assert_eq!(map.entry("x-hello").unwrap().key(), "x-hello");
Trait Implementations
Auto Trait Implementations
impl<'a, VE> RefUnwindSafe for Entry<'a, VE> where
VE: RefUnwindSafe,
impl<'a, VE> !UnwindSafe for Entry<'a, VE>
Blanket Implementations
Mutably borrows from an owned value. Read more
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
pub fn vzip(self) -> V
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more