File Explorer

1"use strict";2/*3 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.4 * SPDX-License-Identifier: Apache-2.0.5 */6var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {7    if (k2 === undefined) k2 = k;8    var desc = Object.getOwnPropertyDescriptor(m, k);9    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {10      desc = { enumerable: true, get: function() { return m[k]; } };11    }12    Object.defineProperty(o, k2, desc);13}) : (function(o, m, k, k2) {14    if (k2 === undefined) k2 = k;15    o[k2] = m[k];16}));17var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {18    Object.defineProperty(o, "default", { enumerable: true, value: v });19}) : function(o, v) {20    o["default"] = v;21});22var __importStar = (this && this.__importStar) || function (mod) {23    if (mod && mod.__esModule) return mod;24    var result = {};25    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);26    __setModuleDefault(result, mod);27    return result;28};29Object.defineProperty(exports, "__esModule", { value: true });30exports.newCancellablePromiseFromNextEvent = exports.CancelController = exports.EVENT_NAME = void 0;31/**32 *33 * A module containing support for cancelling asynchronous operations34 *35 * @packageDocumentation36 * @module cancel37 */38const events_1 = require("events");39const promise = __importStar(require("./promise"));40exports.EVENT_NAME = 'cancelled';41/**42 * CRT implementation of the ICancelController interface43 */44class CancelController {45    constructor(options) {46        this.cancelled = false;47        if (options && options.emitterFactory) {48            this.emitter = options.emitterFactory();49        }50        else {51            this.emitter = new events_1.EventEmitter();52        }53    }54    /**55     * Cancels all asynchronous operations associated with this controller56     */57    cancel() {58        if (!this.cancelled) {59            this.cancelled = true;60            this.emitter.emit(exports.EVENT_NAME);61            this.emitter.removeAllListeners(exports.EVENT_NAME);62        }63    }64    /**65     * Checks whether or not the controller is in the cancelled state66     */67    hasBeenCancelled() {68        return this.cancelled;69    }70    /**71     * Registers a callback to be notified when cancel() is invoked externally.  In general, the callback72     * will cancel an asynchronous operation by rejecting the associated promise.73     *74     * IMPORTANT: The listener is invoked synchronously if the controller has already been cancelled.75     *76     * @param listener - function to invoke on cancel; invoked synchronously if the controller has been cancelled77     *78     * @return undefined if the controller has already been cancelled, otherwise a function object whose invocation79     * will remove the listener from the controller's event emitter.80     *81     */82    addListener(listener) {83        if (this.cancelled) {84            listener();85            return undefined;86        }87        this.emitter.on(exports.EVENT_NAME, listener);88        return () => { this.emitter.removeListener(exports.EVENT_NAME, listener); };89    }90}91exports.CancelController = CancelController;92/**93 * Creates a promise that can be rejected by a CancelController and resolved by the receipt of an event from an94 * EventEmitter.95 *96 * @param config promise creation options97 */98function newCancellablePromiseFromNextEvent(config) {99    let onEvent = undefined;100    let cancelRemoveListener = undefined;101    let liftedPromise = promise.newLiftedPromise();102    onEvent = (eventData) => {103        try {104            if (config.eventDataTransformer) {105                liftedPromise.resolve(config.eventDataTransformer(eventData));106            }107            else {108                liftedPromise.resolve(eventData);109            }110        }111        catch (err) {112            liftedPromise.reject(err);113        }114    };115    config.emitter.addListener(config.eventName, onEvent);116    if (config.cancelController) {117        cancelRemoveListener = config.cancelController.addListener(() => {118            liftedPromise.reject(config.cancelMessage);119        });120    }121    return promise.makeSelfCleaningPromise(liftedPromise.promise, () => {122        if (onEvent) {123            config.emitter.removeListener(config.eventName, onEvent);124        }125        if (cancelRemoveListener) {126            cancelRemoveListener();127        }128    });129}130exports.newCancellablePromiseFromNextEvent = newCancellablePromiseFromNextEvent;131//# sourceMappingURL=cancel.js.map