1 | // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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2 | // SPDX-License-Identifier: Apache-2.0
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3 | /*!
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4 | * The MIT License (MIT)
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5 | *
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6 | * Copyright (c) 2016 Christian Speckner <cnspeckn@googlemail.com>
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7 | *
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8 | * Permission is hereby granted, free of charge, to any person obtaining a copy
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9 | * of this software and associated documentation files (the "Software"), to deal
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10 | * in the Software without restriction, including without limitation the rights
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11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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12 | * copies of the Software, and to permit persons to whom the Software is
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13 | * furnished to do so, subject to the following conditions:
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14 | *
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15 | * The above copyright notice and this permission notice shall be included in
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16 | * all copies or substantial portions of the Software.
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17 | *
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18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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21 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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24 | * THE SOFTWARE.
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25 | */
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26 | var Mutex = /** @class */ (function () {
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27 | function Mutex() {
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28 | this._queue = [];
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29 | this._pending = false;
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30 | }
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31 | Mutex.prototype.isLocked = function () {
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32 | return this._pending;
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33 | };
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34 | Mutex.prototype.acquire = function () {
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35 | var _this = this;
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36 | var ticket = new Promise(function (resolve) {
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37 | return _this._queue.push(resolve);
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38 | });
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39 | if (!this._pending) {
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40 | this._dispatchNext();
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41 | }
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42 | return ticket;
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43 | };
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44 | Mutex.prototype.runExclusive = function (callback) {
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45 | return this.acquire().then(function (release) {
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46 | var result;
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47 | try {
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48 | result = callback();
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49 | }
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50 | catch (e) {
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51 | release();
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52 | throw e;
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53 | }
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54 | return Promise.resolve(result).then(function (x) { return (release(), x); }, function (e) {
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55 | release();
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56 | throw e;
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57 | });
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58 | });
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59 | };
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60 | Mutex.prototype._dispatchNext = function () {
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61 | if (this._queue.length > 0) {
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62 | this._pending = true;
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63 | this._queue.shift()(this._dispatchNext.bind(this));
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64 | }
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65 | else {
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66 | this._pending = false;
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67 | }
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68 | };
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69 | return Mutex;
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70 | }());
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71 | export default Mutex;
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