@newdash/newdash/functional/BlockedQueue.js

javascript/typescript utility library

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BlockedQueue = exports.QueueOverFlowError = void 0;
/* eslint-disable max-len */
const assert_1 = require("../assert");
/**
 *
 * queue pending size out of limit
 *
 * @internal
 * @private
 * @ignore
 */
class QueueOverFlowError extends Error {
}
exports.QueueOverFlowError = QueueOverFlowError;
/**
 * BlockedQueue
 *
 * a blocked queue for async operations
 *
 * @since 5.19.0
 * @category Functional
 */
class BlockedQueue {
    _capacity;
    _notifyQueue;
    _maxPending;
    _container;
    /**
     * @param capacity default 1000
     * @param maxPending default 10 * capacity, the max allowed number of pending items
     */
    constructor(capacity = 1000, maxPending = 10 * capacity) {
        (0, assert_1.mustProvide)(capacity, "capacity", "number");
        (0, assert_1.mustProvide)(maxPending, "maxPending", "number");
        this._capacity = capacity;
        this._container = new Array(0);
        this._notifyQueue = new Array(0);
        this._maxPending = maxPending;
    }
    /**
     * push an item to the queue, blocked when the queue is full
     *
     * @throws {QueueOverFlowError} throw when pending items are too much
     * @param item
     * @returns
     */
    async enQueue(item) {
        if (this._container.length >= this._capacity) {
            if (this._notifyQueue.length <= this._maxPending) {
                return new Promise((resolve) => {
                    this._notifyQueue.push(() => {
                        this._container.push(item);
                        resolve();
                    });
                });
            }
            throw new QueueOverFlowError(`BlockedQueue: the number of pending items is more than the max allowed number of pending items: '${this._maxPending}', value: '${item}'`);
        }
        this._container.push(item);
        return;
    }
    /**
     * retrieve an item from queue
     *
     * @returns
     */
    async deQueue() {
        if (this._container.length > 0) {
            const item = this._container.shift();
            if (this._notifyQueue.length > 0) {
                this._notifyQueue.shift()();
            }
            return item;
        }
        return undefined;
    }
}
exports.BlockedQueue = BlockedQueue;
exports.default = BlockedQueue;