diff options
Diffstat (limited to 'node_modules/jest-worker/build/workers/processChild.js')
-rw-r--r-- | node_modules/jest-worker/build/workers/processChild.js | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/node_modules/jest-worker/build/workers/processChild.js b/node_modules/jest-worker/build/workers/processChild.js new file mode 100644 index 0000000..fdf766e --- /dev/null +++ b/node_modules/jest-worker/build/workers/processChild.js @@ -0,0 +1,148 @@ +'use strict'; + +var _types = require('../types'); + +/** + * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved. + * + * This source code is licensed under the MIT license found in the + * LICENSE file in the root directory of this source tree. + */ +let file = null; +let setupArgs = []; +let initialized = false; +/** + * This file is a small bootstrapper for workers. It sets up the communication + * between the worker and the parent process, interpreting parent messages and + * sending results back. + * + * The file loaded will be lazily initialized the first time any of the workers + * is called. This is done for optimal performance: if the farm is initialized, + * but no call is made to it, child Node processes will be consuming the least + * possible amount of memory. + * + * If an invalid message is detected, the child will exit (by throwing) with a + * non-zero exit code. + */ + +const messageListener = request => { + switch (request[0]) { + case _types.CHILD_MESSAGE_INITIALIZE: + const init = request; + file = init[2]; + setupArgs = request[3]; + break; + + case _types.CHILD_MESSAGE_CALL: + const call = request; + execMethod(call[2], call[3]); + break; + + case _types.CHILD_MESSAGE_END: + end(); + break; + + default: + throw new TypeError( + 'Unexpected request from parent process: ' + request[0] + ); + } +}; + +process.on('message', messageListener); + +function reportSuccess(result) { + if (!process || !process.send) { + throw new Error('Child can only be used on a forked process'); + } + + process.send([_types.PARENT_MESSAGE_OK, result]); +} + +function reportClientError(error) { + return reportError(error, _types.PARENT_MESSAGE_CLIENT_ERROR); +} + +function reportInitializeError(error) { + return reportError(error, _types.PARENT_MESSAGE_SETUP_ERROR); +} + +function reportError(error, type) { + if (!process || !process.send) { + throw new Error('Child can only be used on a forked process'); + } + + if (error == null) { + error = new Error('"null" or "undefined" thrown'); + } + + process.send([ + type, + error.constructor && error.constructor.name, + error.message, + error.stack, + typeof error === 'object' ? {...error} : error + ]); +} + +function end() { + const main = require(file); + + if (!main.teardown) { + exitProcess(); + return; + } + + execFunction(main.teardown, main, [], exitProcess, exitProcess); +} + +function exitProcess() { + // Clean up open handles so the process ideally exits gracefully + process.removeListener('message', messageListener); +} + +function execMethod(method, args) { + const main = require(file); + + let fn; + + if (method === 'default') { + fn = main.__esModule ? main['default'] : main; + } else { + fn = main[method]; + } + + function execHelper() { + execFunction(fn, main, args, reportSuccess, reportClientError); + } + + if (initialized || !main.setup) { + execHelper(); + return; + } + + initialized = true; + execFunction(main.setup, main, setupArgs, execHelper, reportInitializeError); +} + +const isPromise = obj => + !!obj && + (typeof obj === 'object' || typeof obj === 'function') && + typeof obj.then === 'function'; + +function execFunction(fn, ctx, args, onResult, onError) { + let result; + + try { + result = fn.apply(ctx, args); + } catch (err) { + onError(err); + return; + } + + if (isPromise(result)) { + result.then(onResult, onError); + } else { + onResult(result); + } +} |