Struct weak_table::WeakKeyHashMap

pub struct WeakKeyHashMap<K, V, S = RandomState> { /* fields omitted */ }

A hash map with weak keys, hashed on key value.

When a weak pointer expires, its mapping is lazily removed.

Implementations

impl<K: WeakKey, V> WeakKeyHashMap<K, V, RandomState>

pub fn new() -> Self

Creates an empty WeakKeyHashMap.

pub fn with_capacity(capacity: usize) -> Self

Creates an empty WeakKeyHashMap with the given capacity.

impl<K: WeakKey, V, S: BuildHasher> WeakKeyHashMap<K, V, S>

pub fn with_hasher(hash_builder: S) -> Self

Creates an empty WeakKeyHashMap with the given capacity and hasher.

pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> Self

Creates an empty WeakKeyHashMap with the given capacity and hasher.

pub fn hasher(&self) -> &S

Returns a reference to the map’s BuildHasher.

pub fn capacity(&self) -> usize

Returns the number of elements the map can hold without reallocating.

pub fn remove_expired(&mut self)

Removes all mappings whose keys have expired.

pub fn reserve(&mut self, additional_capacity: usize)

Reserves room for additional elements.

pub fn shrink_to_fit(&mut self)

Shrinks the capacity to the minimum allowed to hold the current number of elements.

pub fn len(&self) -> usize

Returns an over-approximation of the number of elements.

pub fn is_empty(&self) -> bool

Is the map empty?

Note that this may return false even if all keys in the map have expired, if they haven’t been collected yet.

pub fn load_factor(&self) -> f32

The proportion of buckets that are used.

This is an over-approximation because of expired keys.

pub fn entry(&mut self, key: K::Strong) -> Entry<'_, K, V>

Gets the requested entry.

pub fn clear(&mut self)

Removes all associations from the map.

pub fn get<Q>(&self, key: &Q) -> Option<&V> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns a reference to the value corresponding to the key.

pub fn contains_key<Q>(&self, key: &Q) -> bool where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns true if the map contains the specified key.

pub fn get_key<Q>(&self, key: &Q) -> Option<K::Strong> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns a strong reference to the key, if found.

pub fn get_both<Q>(&self, key: &Q) -> Option<(K::Strong, &V)> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns a pair of a strong reference to the key, and a reference to the value, if present.

pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns a mutable reference to the value corresponding to the key.

pub fn get_both_mut<Q>(&mut self, key: &Q) -> Option<(K::Strong, &mut V)> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Returns a pair of a strong reference to the key, and a mutable reference to the value, if present.

pub fn insert(&mut self, key: K::Strong, value: V) -> Option<V>

Unconditionally inserts the value, returning the old value if already present.

Unlike std::collections::HashMap, this replaced the key even if occupied.

pub fn remove<Q>(&mut self, key: &Q) -> Option<V> where
    Q: ?Sized + Hash + Eq,
    K::Key: Borrow<Q>, 

Removes the entry with the given key, if it exists, and returns the value.

pub fn retain<F>(&mut self, f: F) where
    F: FnMut(K::Strong, &mut V) -> bool, 

Removes all mappings not satisfying the given predicate.

Also removes any expired mappings.

pub fn is_submap_with<F, S1, V1>(
    &self,
    other: &WeakKeyHashMap<K, V1, S1>,
    cmp: F
) -> bool where
    F: FnMut(&V, &V1) -> bool,
    S1: BuildHasher, 

Is this map a submap of the other under the given value comparison cmp?

In particular, for every key k of self,

• k must also be a key of other and
• cmp(self[k], other[k]) must hold.

pub fn is_submap<V1, S1>(&self, other: &WeakKeyHashMap<K, V1, S1>) -> bool where
    V: PartialEq<V1>,
    S1: BuildHasher, 

Is self a submap of other?

pub fn domain_is_subset<V1, S1>(
    &self,
    other: &WeakKeyHashMap<K, V1, S1>
) -> bool where
    S1: BuildHasher, 

Are the keys of self a subset of the keys of other?

impl<K: WeakElement, V, S> WeakKeyHashMap<K, V, S>

pub fn iter(&self) -> Iter<'_, K, V>

Gets an iterator over the keys and values.

pub fn keys(&self) -> Keys<'_, K, V>

Gets an iterator over the keys.

pub fn values(&self) -> Values<'_, K, V>

Gets an iterator over the values.

pub fn iter_mut(&mut self) -> IterMut<'_, K, V>

Gets an iterator over the keys and mutable values.

pub fn values_mut(&mut self) -> ValuesMut<'_, K, V>

Gets an iterator over the mutable values.

pub fn drain(&mut self) -> Drain<'_, K, V>

Gets a draining iterator, which removes all the values but retains the storage.

Trait Implementations

impl<K: Clone, V: Clone, S: Clone> Clone for WeakKeyHashMap<K, V, S>

fn clone(&self) -> WeakKeyHashMap<K, V, S>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K: WeakElement, V: Debug, S> Debug for WeakKeyHashMap<K, V, S> where
    K::Strong: Debug, 

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

Formats the value using the given formatter.

impl<K: WeakKey, V, S: BuildHasher + Default> Default for WeakKeyHashMap<K, V, S>

fn default() -> Self

Returns the “default value” for a type.

impl<'a, K, V, S> Extend<(&'a <K as WeakElement>::Strong, &'a V)> for WeakKeyHashMap<K, V, S> where
    K: 'a + WeakKey,
    K::Strong: Clone,
    V: 'a + Clone,
    S: BuildHasher, 

fn extend<T: IntoIterator<Item = (&'a K::Strong, &'a V)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<K, V, S> Extend<(<K as WeakElement>::Strong, V)> for WeakKeyHashMap<K, V, S> where
    K: WeakKey,
    S: BuildHasher, 

fn extend<T: IntoIterator<Item = (K::Strong, V)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<K, V, S> FromIterator<(<K as WeakElement>::Strong, V)> for WeakKeyHashMap<K, V, S> where
    K: WeakKey,
    S: BuildHasher + Default, 

fn from_iter<T: IntoIterator<Item = (K::Strong, V)>>(iter: T) -> Self

Creates a value from an iterator.

impl<'a, K, V, S, Q> Index<&'a Q> for WeakKeyHashMap<K, V, S> where
    K: WeakKey,
    K::Key: Borrow<Q>,
    S: BuildHasher,
    Q: ?Sized + Eq + Hash, 

type Output = V

The returned type after indexing.

fn index(&self, index: &'a Q) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'a, K, V, S, Q> IndexMut<&'a Q> for WeakKeyHashMap<K, V, S> where
    K: WeakKey,
    K::Key: Borrow<Q>,
    S: BuildHasher,
    Q: ?Sized + Eq + Hash, 

fn index_mut(&mut self, index: &'a Q) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation.

impl<K: WeakElement, V, S> IntoIterator for WeakKeyHashMap<K, V, S>

type Item = (K::Strong, V)

The type of the elements being iterated over.

type IntoIter = IntoIter<K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, K: WeakElement, V, S> IntoIterator for &'a WeakKeyHashMap<K, V, S>

type Item = (K::Strong, &'a V)

The type of the elements being iterated over.

type IntoIter = Iter<'a, K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, K: WeakElement, V, S> IntoIterator for &'a mut WeakKeyHashMap<K, V, S>

type Item = (K::Strong, &'a mut V)

The type of the elements being iterated over.

type IntoIter = IterMut<'a, K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V, V1, S, S1> PartialEq<WeakKeyHashMap<K, V1, S1>> for WeakKeyHashMap<K, V, S> where
    K: WeakKey,
    V: PartialEq<V1>,
    S: BuildHasher,
    S1: BuildHasher, 

fn eq(&self, other: &WeakKeyHashMap<K, V1, S1>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<K: WeakKey, V: Eq, S: BuildHasher> Eq for WeakKeyHashMap<K, V, S>