pub struct VacantEntry<'a, T> { /* private fields */ }
Expand description

A view into a single empty location in a HeaderMap.

This struct is returned as part of the Entry enum.

Implementations§

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impl<'a, T> VacantEntry<'a, T>

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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().as_str(), "x-hello");
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pub fn into_key(self) -> HeaderName

Take ownership of the key

Examples
let mut map = HeaderMap::new();

if let Entry::Vacant(v) = map.entry("x-hello") {
    assert_eq!(v.into_key().as_str(), "x-hello");
}
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pub fn insert(self, value: T) -> &'a mut T

Insert the value into the entry.

The value will be associated with this entry’s key. A mutable reference to the inserted value will be returned.

Examples
let mut map = HeaderMap::new();

if let Entry::Vacant(v) = map.entry("x-hello") {
    v.insert("world".parse().unwrap());
}

assert_eq!(map["x-hello"], "world");
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pub fn insert_entry(self, value: T) -> OccupiedEntry<'a, T>

Insert the value into the entry.

The value will be associated with this entry’s key. The new OccupiedEntry is returned, allowing for further manipulation.

Examples
let mut map = HeaderMap::new();

if let Entry::Vacant(v) = map.entry("x-hello") {
    let mut e = v.insert_entry("world".parse().unwrap());
    e.insert("world2".parse().unwrap());
}

assert_eq!(map["x-hello"], "world2");

Trait Implementations§

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impl<'a, T> Debug for VacantEntry<'a, T>where T: Debug,

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, T> RefUnwindSafe for VacantEntry<'a, T>where T: RefUnwindSafe,

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impl<'a, T> Send for VacantEntry<'a, T>where T: Send,

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impl<'a, T> Sync for VacantEntry<'a, T>where T: Sync,

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impl<'a, T> Unpin for VacantEntry<'a, T>

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impl<'a, T> !UnwindSafe for VacantEntry<'a, T>

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<'a, T, E> AsTaggedExplicit<'a, E> for Twhere T: 'a,

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fn explicit(self, class: Class, tag: u32) -> TaggedParser<'a, Explicit, Self, E>

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impl<'a, T, E> AsTaggedImplicit<'a, E> for Twhere T: 'a,

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fn implicit( self, class: Class, constructed: bool, tag: u32 ) -> TaggedParser<'a, Implicit, Self, E>

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impl<T> Borrow<T> for Twhere 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 Twhere T: ?Sized,

const: unstable · source§

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

const: unstable · source§

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 Twhere U: From<T>,

const: unstable · source§

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> Pointable for T

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const ALIGN: usize = mem::align_of::<T>()

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same<T> for T

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type Output = T

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

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

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 Twhere U: TryFrom<T>,

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

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for Twhere 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