Enum tonic::metadata::Entry

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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§

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Occupied(OccupiedEntry<'a, VE>)

An occupied entry

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Vacant(VacantEntry<'a, VE>)

A vacant entry

Implementations§

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impl<'a, VE: ValueEncoding> Entry<'a, VE>

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pub fn or_insert(self, default: MetadataValue<VE>) -> &'a mut MetadataValue<VE>

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");
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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");
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pub fn key(&self) -> &MetadataKey<VE>

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§

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impl<'a, VE: Debug + ValueEncoding> Debug for Entry<'a, VE>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, VE> RefUnwindSafe for Entry<'a, VE>
where VE: RefUnwindSafe,

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impl<'a, VE> Send for Entry<'a, VE>
where VE: Send,

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impl<'a, VE> Sync for Entry<'a, VE>
where VE: Sync,

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impl<'a, VE> Unpin for Entry<'a, VE>
where VE: Unpin,

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impl<'a, VE> !UnwindSafe for Entry<'a, VE>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoRequest<T> for T

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fn into_request(self) -> Request<T>

Wrap the input message T in a tonic::Request
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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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
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more