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>

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");

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");
}

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");

pub 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

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");

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.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");

pub 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

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 for VacantEntry<'a, T>

where T: Debug,

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 56 bytes