thi-ng/umbrella

import type { Maybe } from "@thi.ng/api";
import type { ConsCell } from "@thi.ng/dcons";
import type { CacheEntry } from "./api.js";
import { LRUCache } from "./lru.js";

export class MRUCache<K, V> extends LRUCache<K, V> {
    empty(): MRUCache<K, V> {
        return new MRUCache<K, V>(null, this.opts);
    }

    protected resetEntry(e: ConsCell<CacheEntry<K, V>>) {
        this.items.asHead(e);
        return e.value.v;
    }

    protected doSetEntry(
        e: Maybe<ConsCell<CacheEntry<K, V>>>,
        k: K,
        v: V,
        s: number
    ) {
        if (e) {
            this.opts.update?.(k, e.value.v, v);
            e.value.v = v;
            e.value.s = s;
            this.items.asHead(e);
        } else {
            this.items.prepend({ k, v, s });
            this.map.set(k, this.items.head!);
        }
    }
}