Struct VacantEntry

pub struct VacantEntry<'a, K, V, A: Allocator + Clone = Global> { pub(in ::collections::btree::map) key: K, pub(in ::collections::btree::map) handle: Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>, pub(in ::collections::btree::map) dormant_map: DormantMutRef<'a, BTreeMap<K, V, A>>, pub(in ::collections::btree::map) alloc: A, pub(in ::collections::btree::map) _marker: PhantomData<&'a mut (K, V)> }

A view into a vacant entry in a BTreeMap. It is part of the Entry enum.

Fields

key: K
handle: Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>

None for a (empty) map without root

dormant_map: DormantMutRef<'a, BTreeMap<K, V, A>>
alloc: A

The BTreeMap will outlive this IntoIter so we don't care about drop order for alloc.

_marker: PhantomData<&'a mut (K, V)>

Implementations

impl<'a, K: Ord, V, A: Allocator + Clone> VacantEntry<'a, K, V, A>

fn key(&self) -> &K

Gets a reference to the key that would be used when inserting a value through the VacantEntry.

Examples

use std::collections::BTreeMap;

let mut map: BTreeMap<&str, usize> = BTreeMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");

fn into_key(self) -> K

Take ownership of the key.

Examples

use std::collections::BTreeMap;
use std::collections::btree_map::Entry;

let mut map: BTreeMap<&str, usize> = BTreeMap::new();

if let Entry::Vacant(v) = map.entry("poneyland") {
    v.into_key();
}

fn insert(self, value: V) -> &'a mut V

Sets the value of the entry with the VacantEntry's key, and returns a mutable reference to it.

Examples

use std::collections::BTreeMap;
use std::collections::btree_map::Entry;

let mut map: BTreeMap<&str, u32> = BTreeMap::new();

if let Entry::Vacant(o) = map.entry("poneyland") {
    o.insert(37);
}
assert_eq!(map["poneyland"], 37);

fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V, A>

Sets the value of the entry with the VacantEntry's key, and returns an OccupiedEntry.

Examples

use std::collections::BTreeMap;
use std::collections::btree_map::Entry;

let mut map: BTreeMap<&str, u32> = BTreeMap::new();

if let Entry::Vacant(o) = map.entry("poneyland") {
    let entry = o.insert_entry(37);
    assert_eq!(entry.get(), &37);
}
assert_eq!(map["poneyland"], 37);

Trait Implementations

impl<K: Debug + Ord, V, A: Allocator + Clone> Debug for VacantEntry<'_, K, V, A>

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

Auto Trait Implementations

impl<'a, K, V, A = Global> !UnwindSafe for VacantEntry<'a, K, V, A>

impl<'a, K, V, A> Freeze for VacantEntry<'a, K, V, A> where K: Freeze, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: Freeze, DormantMutRef<'a, BTreeMap<K, V, A>>: Freeze, A: Freeze, PhantomData<&'a mut (K, V)>: Freeze,

impl<'a, K, V, A> RefUnwindSafe for VacantEntry<'a, K, V, A> where K: RefUnwindSafe, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: RefUnwindSafe, DormantMutRef<'a, BTreeMap<K, V, A>>: RefUnwindSafe, A: RefUnwindSafe, PhantomData<&'a mut (K, V)>: RefUnwindSafe,

impl<'a, K, V, A> Send for VacantEntry<'a, K, V, A> where K: Send, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: Send, DormantMutRef<'a, BTreeMap<K, V, A>>: Send, A: Send, PhantomData<&'a mut (K, V)>: Send,

impl<'a, K, V, A> Sync for VacantEntry<'a, K, V, A> where K: Sync, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: Sync, DormantMutRef<'a, BTreeMap<K, V, A>>: Sync, A: Sync, PhantomData<&'a mut (K, V)>: Sync,

impl<'a, K, V, A> Unpin for VacantEntry<'a, K, V, A> where K: Unpin, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: Unpin, DormantMutRef<'a, BTreeMap<K, V, A>>: Unpin, A: Unpin, PhantomData<&'a mut (K, V)>: Unpin,

impl<'a, K, V, A> UnsafeUnpin for VacantEntry<'a, K, V, A> where K: UnsafeUnpin, Option<Handle<NodeRef<Mut<'a>, K, V, Leaf>, Edge>>: UnsafeUnpin, DormantMutRef<'a, BTreeMap<K, V, A>>: UnsafeUnpin, A: UnsafeUnpin, PhantomData<&'a mut (K, V)>: UnsafeUnpin,

Blanket Implementations

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

fn type_id(&self) -> TypeId

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

fn borrow(&self) -> &T

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

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

impl<T> From<T> for VacantEntry<'a, K, V, A>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for VacantEntry<'a, K, V, A> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for VacantEntry<'a, K, V, A>

impl<T, U> Into<U> for VacantEntry<'a, K, V, A> 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, K, V, A> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

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

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