@beenotung/tslib/lock.js

utils library in Typescript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Lock = void 0;
exports.createLock = createLock;
const defer_1 = require("./async/defer");
class Lock {
    quota;
    res;
    queue = [];
    constructor(quota = 1) {
        this.quota = quota;
        this.res = quota;
    }
    async acquire(amount = 1) {
        if (amount > this.quota) {
            throw new Error('not enough quota: max=' + this.quota + ', require=' + amount);
        }
        if (this.res >= amount) {
            this.res -= amount;
            return;
        }
        const defer = (0, defer_1.createDefer)();
        this.queue.push({ defer, amount });
        return defer.promise;
    }
    release(amount = 1) {
        this.res += amount;
        this.check();
    }
    check() {
        this.queue = this.queue.filter(item => {
            if (this.res >= item.amount) {
                this.res -= item.amount;
                item.defer.resolve(void 0);
                return false;
            }
            return true;
        });
    }
}
exports.Lock = Lock;
function createLock(quota = 1) {
    return new Lock(quota);
}