@aws-amplify/core/lib-esm/Util/Mutex.js

Core category of aws-amplify

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
/*!
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Christian Speckner <cnspeckn@googlemail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
var Mutex = /** @class */ (function () {
    function Mutex() {
        this._queue = [];
        this._pending = false;
    }
    Mutex.prototype.isLocked = function () {
        return this._pending;
    };
    Mutex.prototype.acquire = function () {
        var _this = this;
        var ticket = new Promise(function (resolve) {
            return _this._queue.push(resolve);
        });
        if (!this._pending) {
            this._dispatchNext();
        }
        return ticket;
    };
    Mutex.prototype.runExclusive = function (callback) {
        return this.acquire().then(function (release) {
            var result;
            try {
                result = callback();
            }
            catch (e) {
                release();
                throw e;
            }
            return Promise.resolve(result).then(function (x) { return (release(), x); }, function (e) {
                release();
                throw e;
            });
        });
    };
    Mutex.prototype._dispatchNext = function () {
        if (this._queue.length > 0) {
            this._pending = true;
            this._queue.shift()(this._dispatchNext.bind(this));
        }
        else {
            this._pending = false;
        }
    };
    return Mutex;
}());
export default Mutex;