Struct VacantEntry

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

A view into a single empty location in a HeaderMap.

This struct is returned as part of the Entry enum.

Implementations

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

fn key(&self) -> &HeaderName

Returns a reference to the entry's key

Examples

# use http::HeaderMap;
let mut map = HeaderMap::new();

assert_eq!(map.entry("x-hello").key().as_str(), "x-hello");

fn into_key(self) -> HeaderName

Take ownership of the key

Examples

# use http::header::{HeaderMap, Entry};
let mut map = HeaderMap::new();

if let Entry::Vacant(v) = map.entry("x-hello") {
    assert_eq!(v.into_key().as_str(), "x-hello");
}

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

# use http::header::{HeaderMap, Entry};
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");

fn try_insert(self, value: T) -> Result<&'a mut T, MaxSizeReached>

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

# use http::header::{HeaderMap, Entry};
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");

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

# use http::header::*;
let mut map = HeaderMap::new();

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

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

fn try_insert_entry(self, value: T) -> Result<OccupiedEntry<'a, T>, MaxSizeReached>

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

# use http::header::*;
let mut map = HeaderMap::new();

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

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

Trait Implementations

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

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

Auto Trait Implementations

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

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

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

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

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

impl<'a, T> Unpin for VacantEntry<'a, T> where &'a mut HeaderMap<T>: Unpin,

impl<'a, T> UnsafeUnpin for VacantEntry<'a, T> where &'a mut HeaderMap<T>: UnsafeUnpin,

Blanket Implementations

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

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for VacantEntry<'a, T> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for VacantEntry<'a, T> where T: ?Sized,

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

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

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into<U> for VacantEntry<'a, T> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

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

impl<T, U> TryFrom<U> for VacantEntry<'a, T> where U: Into<T>,

type Error = never;
fn try_from(value: U) -> Result<T, never>

impl<T, U> TryInto<U> for VacantEntry<'a, T> where U: TryFrom<T>,

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