prex/out/lib/boundedQueue.js

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
    var g = generator.apply(thisArg, _arguments || []), i, q = [];
    return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
    function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
    function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
    function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
    function fulfill(value) { resume("next", value); }
    function reject(value) { resume("throw", value); }
    function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
};
Object.defineProperty(exports, "__esModule", { value: true });
require("./asyncIterable");
const queue_1 = require("./queue");
const utils_1 = require("./utils");
const BOUNDARY = Symbol();
/**
 * An asynchronous queue with a bounded endpoint.
 */
class AsyncBoundedQueue {
    /**
     * Initializes a new instance of the AsyncProducerConsumerQueue class.
     *
     * @param iterable An optional iterable of values or promises.
     */
    constructor(iterable) {
        this._queue = new queue_1.AsyncQueue();
        this._state = "open";
        if (!utils_1.isMissing(iterable) && !utils_1.isIterable(iterable))
            throw new TypeError("Object not iterable: iterable.");
        if (utils_1.isIterable(iterable)) {
            for (const value of iterable) {
                this.put(value);
            }
        }
    }
    /**
     * Gets the number of entries in the queue.
     * When positive, indicates the number of entries available to get.
     * When negative, indicates the number of requests waiting to be fulfilled.
     */
    get size() {
        return this._state === "closing" ? this._queue.size - 1 : this._queue.size;
    }
    /**
     * Adds a value to the end of the queue. If the queue is empty but has a pending
     * dequeue request, the value will be dequeued and the request fulfilled.
     *
     * @param value A value or promise to add to the queue.
     */
    put(value) {
        if (this._state !== "open")
            throw new Error("AsyncProducer is done producing values.");
        this._queue.put(value);
    }
    /**
     * Indicates the queue is done adding and that no more items will be added to the queue.
     */
    end() {
        if (this._state !== "open")
            return;
        this._state = "closing";
        this._queue.put(BOUNDARY);
    }
    /**
     * Removes and returns a Promise for the first value in the queue. If the queue has
     * ended, returns a Promise for `undefined`. If the queue is empty, returns a Promise
     * for the next value to be added to the queue.
     */
    get() {
        return __awaiter(this, void 0, void 0, function* () {
            const result = yield this._dequeue();
            return result === BOUNDARY ? undefined : result;
        });
    }
    /**
     * Consumes all items in the queue until the queue ends.
     */
    drain() {
        return __asyncGenerator(this, arguments, function* drain_1() {
            let value = yield __await(this._dequeue());
            while (value !== BOUNDARY) {
                yield yield __await(value);
                value = yield __await(this._dequeue());
            }
        });
    }
    _dequeue() {
        return __awaiter(this, void 0, void 0, function* () {
            if (this._state === "closed")
                return BOUNDARY;
            let result = BOUNDARY;
            try {
                result = yield this._queue.get();
            }
            finally {
                if (result === BOUNDARY) {
                    this._state = "closed";
                }
            }
            return result;
        });
    }
}
exports.AsyncBoundedQueue = AsyncBoundedQueue;