Struct weak_table::PtrWeakKeyHashMap

pub struct PtrWeakKeyHashMap<K, V, S = RandomState>(_);

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

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

Examples

use weak_table::PtrWeakKeyHashMap;
use std::rc::{Rc, Weak};

type Table = PtrWeakKeyHashMap<Weak<str>, usize>;

let mut map = Table::new();
let a = Rc::<str>::from("hello");
let b = Rc::<str>::from("hello");

map.insert(a.clone(), 5);

assert_eq!( map.get(&a), Some(&5) );
assert_eq!( map.get(&b), None );

map.insert(b.clone(), 7);

assert_eq!( map.get(&a), Some(&5) );
assert_eq!( map.get(&b), Some(&7) );

Methods

impl<K: WeakElement, V> PtrWeakKeyHashMap<K, V, RandomState> where
    K::Strong: Deref, 

pub fn new() -> Self

Creates an empty PtrWeakKeyHashMap.

pub fn with_capacity(capacity: usize) -> Self

Creates an empty PtrWeakKeyHashMap with the given capacity.

impl<K: WeakElement, V, S: BuildHasher> PtrWeakKeyHashMap<K, V, S> where
    K::Strong: Deref, 

pub fn with_hasher(hash_builder: S) -> Self

Creates an empty PtrWeakKeyHashMap with the given capacity and hasher.

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

Creates an empty PtrWeakKeyHashMap 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 known to be empty?

This could answer false for an empty map whose keys have expired but have yet to be collected.

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<ByPtr<K>, V>

Gets the requested entry.

pub fn clear(&mut self)

Removes all associations from the map.

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

Returns a reference to the value corresponding to the key.

pub fn contains_key(&self, key: &K::Strong) -> bool

Returns true if the map contains the specified key.

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

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

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

Unconditionally inserts the value, returning the old value if already present. Does not replace the key.

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

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 submap_with<F, S1, V1>(
    &self,
    other: &PtrWeakKeyHashMap<K, V1, S1>,
    value_equal: F
) -> bool where
    F: FnMut(&V, &V1) -> bool,
    S1: BuildHasher, 

Is this map a submap of the other, using the given value comparison.

In particular, all the keys of self must be in other and the values must compare true with value_equal.

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

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

impl<K: WeakElement, V, S> PtrWeakKeyHashMap<K, V, S> where
    K::Strong: Deref, 

Important traits for Iter<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for Iter<'a, K, V> type Item = (K::Strong, &'a V);

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

Gets an iterator over the keys and values.

Important traits for Keys<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for Keys<'a, K, V> type Item = K::Strong;

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

Gets an iterator over the keys.

Important traits for Values<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for Values<'a, K, V> type Item = &'a V;

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

Gets an iterator over the values.

Important traits for IterMut<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for IterMut<'a, K, V> type Item = (K::Strong, &'a mut V);

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

Gets an iterator over the keys and mutable values.

Important traits for ValuesMut<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for ValuesMut<'a, K, V> type Item = &'a mut V;

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

Gets an iterator over the mutable values.

Important traits for Drain<'a, K, V>

impl<'a, K: WeakElement, V> Iterator for Drain<'a, K, V> type Item = (K::Strong, V);

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

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

Trait Implementations

impl<K, V, V1, S, S1> PartialEq<PtrWeakKeyHashMap<K, V1, S1>> for PtrWeakKeyHashMap<K, V, S> where
    K: WeakElement,
    K::Strong: Deref,
    V: PartialEq<V1>,
    S: BuildHasher,
    S1: BuildHasher, 

fn eq(&self, other: &PtrWeakKeyHashMap<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: WeakElement, V: Eq, S: BuildHasher> Eq for PtrWeakKeyHashMap<K, V, S> where
    K::Strong: Deref, 

impl<K: WeakElement, V, S: BuildHasher + Default> Default for PtrWeakKeyHashMap<K, V, S> where
    K::Strong: Deref, 

fn default() -> Self

Returns the "default value" for a type.

impl<'a, K, V, S> Index<&'a K::Strong> for PtrWeakKeyHashMap<K, V, S> where
    K: WeakElement,
    K::Strong: Deref,
    S: BuildHasher, 

type Output = V

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl<'a, K, V, S> IndexMut<&'a K::Strong> for PtrWeakKeyHashMap<K, V, S> where
    K: WeakElement,
    K::Strong: Deref,
    S: BuildHasher, 

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

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

impl<K, V, S> FromIterator<(K::Strong, V)> for PtrWeakKeyHashMap<K, V, S> where
    K: WeakElement,
    K::Strong: Deref,
    S: BuildHasher + Default, 

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

Creates a value from an iterator.

impl<K, V, S> Extend<(K::Strong, V)> for PtrWeakKeyHashMap<K, V, S> where
    K: WeakElement,
    K::Strong: Deref,
    S: BuildHasher, 

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

Extends a collection with the contents of an iterator.

impl<'a, K, V, S> Extend<(&'a K::Strong, &'a V)> for PtrWeakKeyHashMap<K, V, S> where
    K: 'a + WeakElement,
    K::Strong: Clone + Deref,
    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.

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

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

Formats the value using the given formatter.

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

type Item = (K::Strong, V)

The type of the elements being iterated over.

type IntoIter = IntoIter<ByPtr<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 PtrWeakKeyHashMap<K, V, S>

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

The type of the elements being iterated over.

type IntoIter = Iter<'a, ByPtr<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 PtrWeakKeyHashMap<K, V, S>

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

The type of the elements being iterated over.

type IntoIter = IterMut<'a, ByPtr<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: Clone, V: Clone, S: Clone> Clone for PtrWeakKeyHashMap<K, V, S>

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

Returns a copy of the value.

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

Performs copy-assignment from source.