diff options
Diffstat (limited to 'devtools/shared/worker/worker.js')
| -rw-r--r-- | devtools/shared/worker/worker.js | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/devtools/shared/worker/worker.js b/devtools/shared/worker/worker.js new file mode 100644 index 0000000000..4d753a928e --- /dev/null +++ b/devtools/shared/worker/worker.js @@ -0,0 +1,198 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +"use strict"; + +/* global ChromeWorker */ + +(function (factory) { + if (this.module && module.id.includes("worker")) { + // require + const dumpn = require("devtools/shared/DevToolsUtils").dumpn; + factory.call( + this, + require, + exports, + module, + { Cc, Ci, Cu }, + ChromeWorker, + dumpn + ); + } else { + // Cu.import + const { require } = ChromeUtils.importESModule( + "resource://devtools/shared/loader/Loader.sys.mjs" + ); + this.isWorker = false; + this.console = console; + factory.call( + this, + require, + this, + { exports: this }, + { Cc, Ci, Cu }, + ChromeWorker, + null + ); + this.EXPORTED_SYMBOLS = ["DevToolsWorker", "workerify"]; + } +}).call( + this, + function (require, exports, module, { Ci, Cc }, ChromeWorker, dumpn) { + let MESSAGE_COUNTER = 0; + + /** + * Creates a wrapper around a ChromeWorker, providing easy + * communication to offload demanding tasks. The corresponding URL + * must implement the interface provided by `devtools/shared/worker/helper`. + * + * @param {string} url + * The URL of the worker. + * @param Object opts + * An option with the following optional fields: + * - name: a name that will be printed with logs + * - verbose: log incoming and outgoing messages + */ + function DevToolsWorker(url, opts) { + opts = opts || {}; + this._worker = new ChromeWorker(url); + this._verbose = opts.verbose; + this._name = opts.name; + + this._worker.addEventListener("error", this.onError); + } + exports.DevToolsWorker = DevToolsWorker; + + /** + * Performs the given task in a chrome worker, passing in data. + * Returns a promise that resolves when the task is completed, resulting in + * the return value of the task. + * + * @param {string} task + * The name of the task to execute in the worker. + * @param {any} data + * Data to be passed into the task implemented by the worker. + * @param {undefined|Array} transfer + * Optional array of transferable objects to transfer ownership of. + * @return {Promise} + */ + DevToolsWorker.prototype.performTask = function (task, data, transfer) { + if (this._destroyed) { + return Promise.reject( + "Cannot call performTask on a destroyed DevToolsWorker" + ); + } + const worker = this._worker; + const id = ++MESSAGE_COUNTER; + const payload = { task, id, data }; + + if (this._verbose && dumpn) { + dumpn( + "Sending message to worker" + + (this._name ? " (" + this._name + ")" : "") + + ": " + + JSON.stringify(payload, null, 2) + ); + } + worker.postMessage(payload, transfer); + + return new Promise((resolve, reject) => { + const listener = ({ data: result }) => { + if (this._verbose && dumpn) { + dumpn( + "Received message from worker" + + (this._name ? " (" + this._name + ")" : "") + + ": " + + JSON.stringify(result, null, 2) + ); + } + + if (result.id !== id) { + return; + } + worker.removeEventListener("message", listener); + if (result.error) { + reject(result.error); + } else { + resolve(result.response); + } + }; + + worker.addEventListener("message", listener); + }); + }; + + /** + * Terminates the underlying worker. Use when no longer needing the worker. + */ + DevToolsWorker.prototype.destroy = function () { + this._worker.terminate(); + this._worker = null; + this._destroyed = true; + }; + + DevToolsWorker.prototype.onError = function ({ + message, + filename, + lineno, + }) { + dump(new Error(message + " @ " + filename + ":" + lineno) + "\n"); + }; + + /** + * Takes a function and returns a Worker-wrapped version of the same function. + * Returns a promise upon resolution. + * @see `./devtools/shared/shared/tests/browser/browser_devtools-worker-03.js + * + * ⚠ This should only be used for tests or A/B testing performance ⚠ + * + * The original function must: + * + * Be a pure function, that is, not use any variables not declared within the + * function, or its arguments. + * + * Return a value or a promise. + * + * Note any state change in the worker will not affect the callee's context. + * + * @param {function} fn + * @return {function} + */ + function workerify(fn) { + console.warn( + "`workerify` should only be used in tests or measuring performance. " + + "This creates an object URL on the browser window, and should not be " + + "used in production." + ); + // Fetch modules here as we don't want to include it normally. + const { URL, Blob } = + Services.wm.getMostRecentWindow("navigator:browser"); + const stringifiedFn = createWorkerString(fn); + const blob = new Blob([stringifiedFn]); + const url = URL.createObjectURL(blob); + const worker = new DevToolsWorker(url); + + const wrapperFn = (data, transfer) => + worker.performTask("workerifiedTask", data, transfer); + + wrapperFn.destroy = function () { + URL.revokeObjectURL(url); + worker.destroy(); + }; + + return wrapperFn; + } + exports.workerify = workerify; + + /** + * Takes a function, and stringifies it, attaching the worker-helper.js + * boilerplate hooks. + */ + function createWorkerString(fn) { + return `importScripts("resource://gre/modules/workers/require.js"); + const { createTask } = require("resource://devtools/shared/worker/helper.js"); + createTask(self, "workerifiedTask", ${fn.toString()});`; + } + } +); |