141 lines
3.7 KiB
JavaScript
141 lines
3.7 KiB
JavaScript
'use strict';
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function _jestUtil() {
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const data = require('jest-util');
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_jestUtil = function () {
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return data;
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};
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return data;
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}
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var _types = require('../types');
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/**
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* Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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let file = null;
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let setupArgs = [];
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let initialized = false;
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/**
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* This file is a small bootstrapper for workers. It sets up the communication
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* between the worker and the parent process, interpreting parent messages and
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* sending results back.
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*
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* The file loaded will be lazily initialized the first time any of the workers
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* is called. This is done for optimal performance: if the farm is initialized,
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* but no call is made to it, child Node processes will be consuming the least
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* possible amount of memory.
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*
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* If an invalid message is detected, the child will exit (by throwing) with a
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* non-zero exit code.
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*/
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const messageListener = request => {
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switch (request[0]) {
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case _types.CHILD_MESSAGE_INITIALIZE:
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const init = request;
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file = init[2];
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setupArgs = init[3];
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break;
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case _types.CHILD_MESSAGE_CALL:
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const call = request;
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execMethod(call[2], call[3]);
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break;
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case _types.CHILD_MESSAGE_END:
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end();
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break;
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case _types.CHILD_MESSAGE_MEM_USAGE:
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reportMemoryUsage();
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break;
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default:
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throw new TypeError(
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`Unexpected request from parent process: ${request[0]}`
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);
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}
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};
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process.on('message', messageListener);
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function reportSuccess(result) {
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if (!process || !process.send) {
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throw new Error('Child can only be used on a forked process');
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}
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process.send([_types.PARENT_MESSAGE_OK, result]);
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}
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function reportClientError(error) {
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return reportError(error, _types.PARENT_MESSAGE_CLIENT_ERROR);
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}
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function reportInitializeError(error) {
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return reportError(error, _types.PARENT_MESSAGE_SETUP_ERROR);
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}
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function reportMemoryUsage() {
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if (!process || !process.send) {
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throw new Error('Child can only be used on a forked process');
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}
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const msg = [_types.PARENT_MESSAGE_MEM_USAGE, process.memoryUsage().heapUsed];
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process.send(msg);
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}
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function reportError(error, type) {
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if (!process || !process.send) {
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throw new Error('Child can only be used on a forked process');
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}
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if (error == null) {
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error = new Error('"null" or "undefined" thrown');
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}
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process.send([
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type,
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error.constructor && error.constructor.name,
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error.message,
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error.stack,
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typeof error === 'object'
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? {
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...error
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}
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: error
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]);
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}
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function end() {
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const main = require(file);
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if (!main.teardown) {
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exitProcess();
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return;
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}
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execFunction(main.teardown, main, [], exitProcess, exitProcess);
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}
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function exitProcess() {
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// Clean up open handles so the process ideally exits gracefully
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process.removeListener('message', messageListener);
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}
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function execMethod(method, args) {
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const main = require(file);
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let fn;
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if (method === 'default') {
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fn = main.__esModule ? main.default : main;
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} else {
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fn = main[method];
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}
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function execHelper() {
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execFunction(fn, main, args, reportSuccess, reportClientError);
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}
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if (initialized || !main.setup) {
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execHelper();
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return;
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}
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initialized = true;
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execFunction(main.setup, main, setupArgs, execHelper, reportInitializeError);
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}
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function execFunction(fn, ctx, args, onResult, onError) {
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let result;
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try {
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result = fn.apply(ctx, args);
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} catch (err) {
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onError(err);
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return;
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}
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if ((0, _jestUtil().isPromise)(result)) {
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result.then(onResult, onError);
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} else {
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onResult(result);
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}
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}
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