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							170 lines
						
					
					
						
							3.7 KiB
						
					
					
				
			
		
		
	
	
							170 lines
						
					
					
						
							3.7 KiB
						
					
					
				| 'use strict';
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| 
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| function _worker_threads() {
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|   const data = require('worker_threads');
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| 
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|   _worker_threads = function () {
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|     return data;
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|   };
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| 
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|   return data;
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| }
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| 
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| function _types() {
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|   const data = require('../types');
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| 
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|   _types = function () {
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|     return data;
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|   };
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| 
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|   return data;
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| }
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| 
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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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| 
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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 = request[3];
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|       break;
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| 
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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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| 
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|     case _types().CHILD_MESSAGE_END:
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|       end();
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|       break;
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| 
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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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| 
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| _worker_threads().parentPort.on('message', messageListener);
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| 
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| function reportSuccess(result) {
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|   if (_worker_threads().isMainThread) {
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|     throw new Error('Child can only be used on a forked process');
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|   }
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| 
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|   _worker_threads().parentPort.postMessage([
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|     _types().PARENT_MESSAGE_OK,
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|     result
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|   ]);
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| }
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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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| 
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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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| 
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| function reportError(error, type) {
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|   if (_worker_threads().isMainThread) {
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|     throw new Error('Child can only be used on a forked process');
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|   }
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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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| 
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|   _worker_threads().parentPort.postMessage([
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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' ? {...error} : error
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|   ]);
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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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| 
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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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| 
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|   execFunction(main.teardown, main, [], exitProcess, exitProcess);
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| }
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| 
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| function exitProcess() {
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|   // Clean up open handles so the worker ideally exits gracefully
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|   _worker_threads().parentPort.removeListener('message', messageListener);
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| }
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| 
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| function execMethod(method, args) {
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|   const main = require(file);
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| 
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|   let fn;
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| 
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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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| 
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|   function execHelper() {
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|     execFunction(fn, main, args, reportSuccess, reportClientError);
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|   }
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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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| 
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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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| 
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| const isPromise = obj =>
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|   !!obj &&
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|   (typeof obj === 'object' || typeof obj === 'function') &&
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|   typeof obj.then === 'function';
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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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| 
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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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| 
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|   if (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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