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import { MinPriorityQueue } from '@datastructures-js/priority-queue';
import { Store } from './base-store.js';
// minimum delay between sweeps to avoid repeatedly
// sweeping entries close in proximity one by one.
const MIN_THRESHOLD_MS = 2500;
export default class MemoryStore extends Store {
#store = new Map();
#timeouts = new MinPriorityQueue/*<{ t: number, k: unknown }>*/((obj) => obj.t);
#nextSweep = { id: null, t: null };
constructor(name) {
super(name);
}
_has(key) {
return this.#store.has(key);
}
_get(key) {
const val = this.#store.get(key);
return val === undefined ? null : val;
}
_set(key, val, exp_sec = -1) {
if (this.#store.has(key)) {
this.#timeouts.remove(o => o.k === key);
}
if (exp_sec > 0) {
const exp = 1000 * exp_sec;
const timeout_at = +new Date() + exp;
this.#timeouts.enqueue({ k: key, t: timeout_at });
}
this.#store.set(key, val);
this.#reschedule();
}
#reschedule() {
const current_time = new Date().getTime();
const time = this.#timeouts.front()?.t;
if (!time) {
return;
} else if (time < current_time) {
return this.#sweepNow();
}
const sweep = this.#nextSweep;
if (sweep.id === null || sweep.t > time) {
if (sweep.id) {
clearTimeout(sweep.id);
}
sweep.t = time;
sweep.id = setTimeout(
() => this.#sweepNow(),
Math.max(MIN_THRESHOLD_MS, time - current_time)
);
sweep.id.unref();
}
}
#sweepNow() {
while (this.#timeouts.front()?.t < new Date().getTime()) {
const item = this.#timeouts.dequeue();
this.#store.delete(item.k);
}
this.#nextSweep.id = null;
this.#nextSweep.t = null;
this.#reschedule();
}
}
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