Struct ttl_cache::TtlCache

pub struct TtlCache<K: Eq + Hash, V, S: BuildHasher = RandomState> { /* fields omitted */ }

A time sensitive cache.

Methods

impl<K: Eq + Hash, V> TtlCache<K, V>

pub fn new(capacity: usize) -> Self

Creates an empty cache that can hold at most capacity items.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache: TtlCache<i32, &str> = TtlCache::new(10);

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

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

Creates an empty cache that can hold at most capacity items that expire after duration with the given hash builder.

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

Check if the cache contains the given key.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(10);
cache.insert(1,"a", Duration::from_secs(30));
assert_eq!(cache.contains_key(&1), true);

pub fn insert(&mut self, k: K, v: V, ttl: Duration) -> Option<V>

Inserts a key-value pair into the cache with an individual ttl for the key. If the key already existed and hasn't expired, the old value is returned.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);

cache.insert(1, "a", Duration::from_secs(20));
cache.insert(2, "b", Duration::from_secs(60));
assert_eq!(cache.get_mut(&1), Some(&mut "a"));
assert_eq!(cache.get_mut(&2), Some(&mut "b"));

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

Returns a reference to the value corresponding to the given key in the cache, if it contains an unexpired entry.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);

cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(2, "c", duration);
cache.insert(3, "d", duration);

assert_eq!(cache.get_mut(&1), None);
assert_eq!(cache.get_mut(&2), Some(&mut "c"));

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

Returns a mutable reference to the value corresponding to the given key in the cache, if it contains an unexpired entry.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);

cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(2, "c", duration);
cache.insert(3, "d", duration);

assert_eq!(cache.get_mut(&1), None);
assert_eq!(cache.get_mut(&2), Some(&mut "c"));

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

Removes the given key from the cache and returns its corresponding value.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);

cache.insert(2, "a", Duration::from_secs(30));

assert_eq!(cache.remove(&1), None);
assert_eq!(cache.remove(&2), Some("a"));
assert_eq!(cache.remove(&2), None);

pub fn capacity(&self) -> usize

Returns the maximum number of key-value pairs the cache can hold.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache: TtlCache<i32, &str> = TtlCache::new(2);
assert_eq!(cache.capacity(), 2);

pub fn set_capacity(&mut self, capacity: usize)

Sets the number of key-value pairs the cache can hold. Removes oldest key-value pairs if necessary.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);

cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(3, "c", duration);

assert_eq!(cache.get_mut(&1), None);
assert_eq!(cache.get_mut(&2), Some(&mut "b"));
assert_eq!(cache.get_mut(&3), Some(&mut "c"));

cache.set_capacity(3);
cache.insert(1, "a", duration);
cache.insert(2, "b", duration);

assert_eq!(cache.get_mut(&1), Some(&mut "a"));
assert_eq!(cache.get_mut(&2), Some(&mut "b"));
assert_eq!(cache.get_mut(&3), Some(&mut "c"));

cache.set_capacity(1);

assert_eq!(cache.get_mut(&1), None);
assert_eq!(cache.get_mut(&2), Some(&mut "b"));
assert_eq!(cache.get_mut(&3), None);

pub fn clear(&mut self)

Clears all values out of the cache

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

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

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

Returns an iterator over the cache's key-value pairs in oldest to youngest order.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);

cache.insert(1, 10, duration);
cache.insert(2, 20, duration);
cache.insert(3, 30, duration);

let kvs: Vec<_> = cache.iter().collect();
assert_eq!(kvs, [(&2, &20), (&3, &30)]);

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

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

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

Returns an iterator over the cache's key-value pairs in oldest to youngest order with mutable references to the values.

Examples

use std::time::Duration;
use ttl_cache::TtlCache;

let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);

cache.insert(1, 10, duration);
cache.insert(2, 20, duration);
cache.insert(3, 30, duration);

let mut n = 2;

for (k, v) in cache.iter_mut() {
    assert_eq!(*k, n);
    assert_eq!(*v, n * 10);
    *v *= 10;
    n += 1;
}

assert_eq!(n, 4);
assert_eq!(cache.get_mut(&2), Some(&mut 200));
assert_eq!(cache.get_mut(&3), Some(&mut 300));

Trait Implementations

impl<K: Eq + Hash, V> Clone for TtlCache<K, V> where
    K: Clone,
    V: Clone, 

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

Returns a copy of the value.

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

Performs copy-assignment from source.