freqache

A weighted, futures-aware Rust LFU cache which supports a custom eviction policy.

LFUCache is not thread-safe by itself; for thread safety, use a tokio::sync::Mutex.

Example:

use async_trait::async_trait;
use futures::executor::block_on;
use freqache::LFUCache;

#[derive(Clone, Debug, Eq, PartialEq)]
struct Entry;

impl freqache::Entry for Entry {
    fn weight(&self) -> u64 {
        1
    }
}

struct Policy;

#[async_trait]
impl freqache::Policy<String, Entry> for Policy {
    fn can_evict(&self, value: &Entry) -> bool {
        true
    }

    async fn evict(&self, key: String, value: &Entry) {
        // maybe backup the entry contents here
    }
}

let mut cache = LFUCache::new(1, Policy);
cache.insert("key".to_string(), Entry);

if cache.is_full() {
    block_on(cache.evict());
}