workers: initial implementation #2133
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workers: initial implementation
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,216 @@ | ||
| 'use strict'; | ||
|
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| if (!process.features.experimental_workers) { | ||
| throw new Error('Experimental workers are not enabled'); | ||
| } | ||
|
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| const util = require('util'); | ||
| const assert = require('assert'); | ||
| const EventEmitter = require('events'); | ||
| const WorkerContextBinding = process.binding('worker_context'); | ||
| const JSONStringify = function(value) { | ||
| if (value === undefined) value = null; | ||
| return JSON.stringify(value); | ||
| }; | ||
| const JSONParse = JSON.parse; | ||
| const EMPTY_ARRAY = []; | ||
|
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| const workerContextSymbol = Symbol('workerContext'); | ||
| const installEventsSymbol = Symbol('installEvents'); | ||
| const checkAliveSymbol = Symbol('checkAlive'); | ||
| const initSymbol = WorkerContextBinding.initSymbol; | ||
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| const builtinErrorTypes = new Map([ | ||
| Error, SyntaxError, RangeError, URIError, TypeError, EvalError, ReferenceError | ||
| ].map(function(Type) { | ||
| return [Type.name, Type]; | ||
| })); | ||
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| const Worker = WorkerContextBinding.JsConstructor; | ||
| util.inherits(Worker, EventEmitter); | ||
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| Worker.prototype[initSymbol] = function(entryModulePath, options) { | ||
| if (typeof entryModulePath !== 'string') | ||
| throw new TypeError('entryModulePath must be a string'); | ||
| EventEmitter.call(this); | ||
| options = Object(options); | ||
| const keepAlive = | ||
| options.keepAlive === undefined ? true : !!options.keepAlive; | ||
| const evalCode = !!options.eval; | ||
| const userData = JSONStringify(options.data); | ||
| this[workerContextSymbol] = | ||
| new WorkerContextBinding.WorkerContext(entryModulePath, { | ||
| keepAlive: keepAlive, | ||
| userData: userData, | ||
| eval: evalCode | ||
| }); | ||
| this[installEventsSymbol](); | ||
| }; | ||
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| Worker.prototype[installEventsSymbol] = function() { | ||
| const workerObject = this; | ||
| const workerContext = this[workerContextSymbol]; | ||
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| const onerror = function(payload) { | ||
| var ErrorConstructor = builtinErrorTypes.get(payload.builtinType); | ||
| if (typeof ErrorConstructor !== 'function') | ||
| ErrorConstructor = Error; | ||
| const error = new ErrorConstructor(payload.message); | ||
| error.stack = payload.stack; | ||
| util._extend(error, payload.additionalProperties); | ||
| workerObject.emit('error', error); | ||
| }; | ||
|
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| workerContext._onexit = function(exitCode) { | ||
| workerObject[workerContextSymbol] = null; | ||
| workerObject.emit('exit', exitCode); | ||
| }; | ||
|
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| workerContext._onmessage = function(payload, messageType) { | ||
| payload = JSONParse(payload); | ||
| switch (messageType) { | ||
| case WorkerContextBinding.USER: | ||
| return workerObject.emit('message', payload); | ||
| case WorkerContextBinding.EXCEPTION: | ||
| return onerror(payload); | ||
| default: | ||
| assert.fail('unreachable'); | ||
| } | ||
| }; | ||
| }; | ||
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| Worker.prototype[checkAliveSymbol] = function() { | ||
| if (!this[workerContextSymbol]) | ||
| throw new RangeError('this worker has been terminated'); | ||
| }; | ||
|
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| Worker.prototype.postMessage = function(payload) { | ||
| this[checkAliveSymbol](); | ||
| this[workerContextSymbol].postMessage(JSONStringify(payload), | ||
| EMPTY_ARRAY, | ||
| WorkerContextBinding.USER); | ||
| }; | ||
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| Worker.prototype.terminate = function(callback) { | ||
|
Contributor
There was a problem hiding this comment. This may be naive, but maybe we could use the same vocab as There was a problem hiding this comment. @tflanagan depends on what you want to be closer to: node |
||
| this[checkAliveSymbol](); | ||
| const context = this[workerContextSymbol]; | ||
| this[workerContextSymbol] = null; | ||
| if (typeof callback === 'function') { | ||
| this.once('exit', function(exitCode) { | ||
| callback(null, exitCode); | ||
| }); | ||
| } | ||
| context.terminate(); | ||
| }; | ||
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| Worker.prototype.ref = function() { | ||
| this[checkAliveSymbol](); | ||
| this[workerContextSymbol].ref(); | ||
| }; | ||
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| Worker.prototype.unref = function() { | ||
| this[checkAliveSymbol](); | ||
| this[workerContextSymbol].unref(); | ||
| }; | ||
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| if (process.isWorkerThread) { | ||
| const postMessage = function(payload, transferList, type) { | ||
| if (!Array.isArray(transferList)) | ||
| throw new TypeError('transferList must be an array'); | ||
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| WorkerContextBinding.workerWrapper._postMessage(JSONStringify(payload), | ||
| transferList, | ||
| type); | ||
| }; | ||
| const workerFatalError = function(er) { | ||
| const defaultStack = null; | ||
| const defaultMessage = '[toString() conversion failed]'; | ||
| const defaultBuiltinType = 'Error'; | ||
|
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| var message = defaultMessage; | ||
| var builtinType = defaultBuiltinType; | ||
| var stack = defaultStack; | ||
| var additionalProperties = {}; | ||
|
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| // As this is a fatal error handler we cannot throw any new errors here | ||
| // but should still try to extract as much info as possible from the | ||
| // cause. | ||
| if (er instanceof Error) { | ||
| // .name can be a getter that throws. | ||
| try { | ||
| builtinType = er.name; | ||
| } catch (ignore) {} | ||
|
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| if (typeof builtinType !== 'string') | ||
| builtinType = defaultBuiltinType; | ||
|
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| // .stack can be a getter that throws. | ||
| try { | ||
| stack = er.stack; | ||
| } catch (ignore) {} | ||
|
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| if (typeof stack !== 'string') | ||
| stack = defaultStack; | ||
|
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| try { | ||
| // Get inherited enumerable properties. | ||
| // .name, .stack and .message are all non-enumerable | ||
| for (var key in er) | ||
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| additionalProperties[key] = er[key]; | ||
| // The message delivery must always succeed, otherwise the real cause | ||
| // of this fatal error is masked. | ||
| JSONStringify(additionalProperties); | ||
| } catch (e) { | ||
| additionalProperties = {}; | ||
| } | ||
| } | ||
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| try { | ||
| // .message can be a getter that throws or the call to toString may fail. | ||
| if (er instanceof Error) { | ||
| message = er.message; | ||
| if (typeof message !== 'string') | ||
| message = '' + er; | ||
| } else { | ||
| message = '' + er; | ||
| } | ||
| } catch (e) { | ||
| message = defaultMessage; | ||
| } | ||
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| postMessage({ | ||
| message: message, | ||
| stack: stack, | ||
| additionalProperties: additionalProperties, | ||
| builtinType: builtinType | ||
| }, EMPTY_ARRAY, WorkerContextBinding.EXCEPTION); | ||
| }; | ||
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| util._extend(Worker, EventEmitter.prototype); | ||
| EventEmitter.call(Worker); | ||
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| WorkerContextBinding.workerWrapper._onmessage = | ||
| function(payload, messageType) { | ||
| payload = JSONParse(payload); | ||
| switch (messageType) { | ||
| case WorkerContextBinding.USER: | ||
| return Worker.emit('message', payload); | ||
| default: | ||
| assert.fail('unreachable'); | ||
| } | ||
| }; | ||
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| Worker.postMessage = function(payload) { | ||
| postMessage(payload, EMPTY_ARRAY, WorkerContextBinding.USER); | ||
| }; | ||
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| Object.defineProperty(Worker, '_workerFatalError', { | ||
| configurable: true, | ||
| writable: false, | ||
| enumerable: false, | ||
| value: workerFatalError | ||
| }); | ||
| } | ||
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| module.exports = Worker; | ||
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maybe use arrow functions for these events so you don't have to do
const workerObject = this;?