Struct cachemap2::CacheMap

pub struct CacheMap<K, V, S = RandomState> { /* private fields */ }

An insert-only map for caching the result of functions

Implementations

impl<K: Eq + Hash, V, S: BuildHasher> CacheMap<K, V, S>

pub fn cache<F: FnOnce() -> V>(&self, key: K, f: F) -> &V

Fetch the value associated with the key, or run the provided function to insert one.

Example

use cachemap2::CacheMap;

let m = CacheMap::new();

let fst = m.cache("key", || 5u32);
let snd = m.cache("key", || 7u32);

assert_eq!(*fst, *snd);
assert_eq!(*fst, 5u32);

pub fn cache_default(&self, key: K) -> &V

where V: Default,

Fetch the value associated with the key, or insert a default value.

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

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Return whether the map contains the given key.

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

Return an iterator over the map.

This iterator will lock the underlying map until it is dropped.

impl<K: Eq + Hash, V> CacheMap<K, V, RandomState>

pub fn new() -> Self

Creates a new CacheMap

impl<K: Eq + Hash, V, S: BuildHasher + Default> CacheMap<K, V, S>

pub fn with_hasher(hash_builder: S) -> Self

Creates a new CacheMap with the provided hasher

Trait Implementations

impl<K: Eq + Hash, V, S: BuildHasher + Default> Default for CacheMap<K, V, S>

fn default() -> Self

Returns the “default value” for a type.

impl<K: Eq + Hash, V, S: BuildHasher + Default> FromIterator<(K, V)> for CacheMap<K, V, S>

fn from_iter<T>(iter: T) -> Self

where T: IntoIterator<Item = (K, V)>,

Creates a value from an iterator.

impl<'a, K, V, S> IntoIterator for &'a CacheMap<K, V, S>

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

The type of the elements being iterated over.

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

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V, S> IntoIterator for CacheMap<K, V, S>

type Item = (K, 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.