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>

fn new(duration: Duration, capacity: usize) -> Self

Creates an empty cache that can hold at most capacity items and will expire them after duration

Examples

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

let mut cache: TtlCache<i32, &str> = TtlCache::new(Duration::from_secs(30), 10);

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

fn with_hasher(duration: Duration, 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.

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

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

Inserts a key-value pair into the cache. 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(Duration::from_secs(30), 2);

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

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(Duration::from_secs(30), 2);

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

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

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(Duration::from_secs(30), 2);

cache.insert(2, "a");

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

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(Duration::from_secs(30), 2);
assert_eq!(cache.capacity(), 2);

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(Duration::from_secs(30), 2);

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

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");
cache.insert(2, "b");

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);

fn clear(&mut self)

Clears all values out of the cache

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(Duration::from_secs(30), 2);

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

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

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(Duration::from_secs(30), 2);

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

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

fn clone(&self) -> TtlCache<K, V, S>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<K: Eq + Hash, V, S: BuildHasher> Extend<(K, V)> for TtlCache<K, V, S>

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

Extends a collection with the contents of an iterator.