Struct WeakMap

pub struct WeakMap<K, V> { /* private fields */ }

A B-Tree map that stores weak references to values.

Implementations

impl<K, V> WeakMap<K, V>

pub const fn new() -> Self

Makes a new, empty WeakMap.

Does not allocate anything on its own.

impl<K, V> WeakMap<K, V>

pub fn clear(&mut self)

Clears the map, removing all elements.

pub fn raw_len(&self) -> usize

Returns the number of elements in the underlying map.

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

Gets an iterator over the entries of the map, sorted by key.

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

Gets an iterator over the keys of the map, in sorted order.

pub fn into_keys(self) -> IntoKeys<K, V>

Creates a consuming iterator visiting all the keys, in sorted order. The map cannot be used after calling this.

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

Gets an iterator over the values of the map, in order by key.

pub fn into_values(self) -> IntoValues<K, V>

Creates a consuming iterator visiting all the values, in order by key. The map cannot be used after calling this.

impl<K, V> WeakMap<K, V>

where K: Ord, V: WeakRef,

pub fn cleanup(&mut self)

Cleans up the map by removing expired values.

Usually you don’t need to call this manually, as it is called automatically when the number of operations reaches a threshold.

pub fn len(&self) -> usize

Returns the number of elements in the map, excluding expired values.

This is a linear operation, as it iterates over all elements in the map.

The returned value may be less than the result of Self::raw_len.

pub fn is_empty(&self) -> bool

Returns true if the map contains no valid elements.

pub fn retain<F>(&mut self, f: F)

where F: FnMut(&K, V::Strong) -> bool,

Retains only the elements specified by the predicate.

pub fn get<Q>(&self, key: &Q) -> Option<V::Strong>

where K: Borrow<Q>, Q: Ord + ?Sized,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

pub fn get_key_value<Q>(&self, key: &Q) -> Option<(&K, V::Strong)>

where K: Borrow<Q>, Q: Ord + ?Sized,

Returns the key-value pair corresponding to the supplied key. This is potentially useful:

• for key types where non-identical keys can be considered equal;
• for getting the &K stored key value from a borrowed &Q lookup key; or
• for getting a reference to a key with the same lifetime as the collection.

The supplied key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

pub fn contains_key<Q>(&self, key: &Q) -> bool

where K: Borrow<Q>, Q: Ord + ?Sized,

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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

Inserts a key-value pair into the map.

If the map did not have this key present, None is returned.

If the map did have this key present, the value is updated, and the old value is returned. The key is not updated, though; this matters for types that can be == without being identical. See the module-level documentation for more.

pub fn remove<Q>(&mut self, key: &Q) -> Option<V::Strong>

where K: Borrow<Q>, Q: Ord + ?Sized,

Removes a key from the map, returning the value at the key if the key was previously in the map.

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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

where K: Borrow<Q>, Q: Ord + ?Sized,

Removes a key from the map, returning the stored key and value if the key was previously in the map.

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

pub fn upgrade(&self) -> StrongMap<K, V::Strong>

where K: Clone,

Upgrade this WeakMap to a StrongMap.

Trait Implementations

impl<K: Clone, V: Clone> Clone for WeakMap<K, V>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<K, V> Debug for WeakMap<K, V>

where K: Debug, V: WeakRef, V::Strong: Debug,

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

Formats the value using the given formatter.

impl<K, V> Default for WeakMap<K, V>

fn default() -> Self

Returns the “default value” for a type.

impl<K, V> From<&BTreeMap<K, <V as WeakRef>::Strong>> for WeakMap<K, V>

where K: Ord + Clone, V: WeakRef,

fn from(value: &StrongMap<K, V::Strong>) -> Self

Converts to this type from the input type.

impl<K, V, const N: usize> From<[(K, &<V as WeakRef>::Strong); N]> for WeakMap<K, V>

where K: Ord, V: WeakRef,

fn from(array: [(K, &V::Strong); N]) -> Self

Converts to this type from the input type.

impl<K, V> From<BTreeMap<K, V>> for WeakMap<K, V>

fn from(inner: BTreeMap<K, V>) -> Self

Converts to this type from the input type.

impl<K, V> From<WeakMap<K, V>> for BTreeMap<K, V>

fn from(map: WeakMap<K, V>) -> Self

Converts to this type from the input type.

impl<'a, K, V> FromIterator<(K, &'a <V as WeakRef>::Strong)> for WeakMap<K, V>

where K: Ord, V: WeakRef,

fn from_iter<T: IntoIterator<Item = (K, &'a V::Strong)>>(iter: T) -> Self

Creates a value from an iterator.

impl<'a, K, V> IntoIterator for &'a WeakMap<K, V>

where V: WeakRef,

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

Which kind of iterator are we turning this into?

type Item = (&'a K, <V as WeakRef>::Strong)

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V> IntoIterator for WeakMap<K, V>

where V: WeakRef,

type IntoIter = IntoIter<K, V>

Which kind of iterator are we turning this into?

type Item = (K, <V as WeakRef>::Strong)

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V> PartialEq for WeakMap<K, V>

where K: Ord, V: WeakRef,

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<K, V> Eq for WeakMap<K, V>

where K: Ord, V: WeakRef,