source: trip-planner-front/node_modules/jest-worker/build/workers/threadChild.js@ fa375fe

Last change on this file since fa375fe was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 3.6 KB
Line 
1'use strict';
2
3function _worker_threads() {
4 const data = require('worker_threads');
5
6 _worker_threads = function () {
7 return data;
8 };
9
10 return data;
11}
12
13var _types = require('../types');
14
15/**
16 * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
17 *
18 * This source code is licensed under the MIT license found in the
19 * LICENSE file in the root directory of this source tree.
20 */
21let file = null;
22let setupArgs = [];
23let initialized = false;
24/**
25 * This file is a small bootstrapper for workers. It sets up the communication
26 * between the worker and the parent process, interpreting parent messages and
27 * sending results back.
28 *
29 * The file loaded will be lazily initialized the first time any of the workers
30 * is called. This is done for optimal performance: if the farm is initialized,
31 * but no call is made to it, child Node processes will be consuming the least
32 * possible amount of memory.
33 *
34 * If an invalid message is detected, the child will exit (by throwing) with a
35 * non-zero exit code.
36 */
37
38const messageListener = request => {
39 switch (request[0]) {
40 case _types.CHILD_MESSAGE_INITIALIZE:
41 const init = request;
42 file = init[2];
43 setupArgs = request[3];
44 break;
45
46 case _types.CHILD_MESSAGE_CALL:
47 const call = request;
48 execMethod(call[2], call[3]);
49 break;
50
51 case _types.CHILD_MESSAGE_END:
52 end();
53 break;
54
55 default:
56 throw new TypeError(
57 'Unexpected request from parent process: ' + request[0]
58 );
59 }
60};
61
62_worker_threads().parentPort.on('message', messageListener);
63
64function reportSuccess(result) {
65 if (_worker_threads().isMainThread) {
66 throw new Error('Child can only be used on a forked process');
67 }
68
69 _worker_threads().parentPort.postMessage([_types.PARENT_MESSAGE_OK, result]);
70}
71
72function reportClientError(error) {
73 return reportError(error, _types.PARENT_MESSAGE_CLIENT_ERROR);
74}
75
76function reportInitializeError(error) {
77 return reportError(error, _types.PARENT_MESSAGE_SETUP_ERROR);
78}
79
80function reportError(error, type) {
81 if (_worker_threads().isMainThread) {
82 throw new Error('Child can only be used on a forked process');
83 }
84
85 if (error == null) {
86 error = new Error('"null" or "undefined" thrown');
87 }
88
89 _worker_threads().parentPort.postMessage([
90 type,
91 error.constructor && error.constructor.name,
92 error.message,
93 error.stack,
94 typeof error === 'object' ? {...error} : error
95 ]);
96}
97
98function end() {
99 const main = require(file);
100
101 if (!main.teardown) {
102 exitProcess();
103 return;
104 }
105
106 execFunction(main.teardown, main, [], exitProcess, exitProcess);
107}
108
109function exitProcess() {
110 // Clean up open handles so the worker ideally exits gracefully
111 _worker_threads().parentPort.removeListener('message', messageListener);
112}
113
114function execMethod(method, args) {
115 const main = require(file);
116
117 let fn;
118
119 if (method === 'default') {
120 fn = main.__esModule ? main['default'] : main;
121 } else {
122 fn = main[method];
123 }
124
125 function execHelper() {
126 execFunction(fn, main, args, reportSuccess, reportClientError);
127 }
128
129 if (initialized || !main.setup) {
130 execHelper();
131 return;
132 }
133
134 initialized = true;
135 execFunction(main.setup, main, setupArgs, execHelper, reportInitializeError);
136}
137
138const isPromise = obj =>
139 !!obj &&
140 (typeof obj === 'object' || typeof obj === 'function') &&
141 typeof obj.then === 'function';
142
143function execFunction(fn, ctx, args, onResult, onError) {
144 let result;
145
146 try {
147 result = fn.apply(ctx, args);
148 } catch (err) {
149 onError(err);
150 return;
151 }
152
153 if (isPromise(result)) {
154 result.then(onResult, onError);
155 } else {
156 onResult(result);
157 }
158}
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