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/* 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.indexOf("worker") >= 0) {
// require
const { Cc, Ci, Cu, ChromeWorker } = require("chrome");
const dumpn = require("devtools/shared/DevToolsUtils").dumpn;
factory.call(this, require, exports, module, { Cc, Ci, Cu }, ChromeWorker, dumpn);
} else {
// Cu.import
const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
this.isWorker = false;
this.Promise = Cu.import("resource://gre/modules/Promise.jsm", {}).Promise;
this.console = Cu.import("resource://gre/modules/Console.jsm", {}).console;
factory.call(
this, require, this, { exports: this },
{ Cc, Ci, Cu }, ChromeWorker, null
);
this.EXPORTED_SYMBOLS = ["DevToolsWorker"];
}
}).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`.
*
* @see `./devtools/client/shared/widgets/GraphsWorker.js`
*
* @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, false);
}
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.
* @return {Promise}
*/
DevToolsWorker.prototype.performTask = function (task, data) {
if (this._destroyed) {
return Promise.reject("Cannot call performTask on a destroyed DevToolsWorker");
}
let worker = this._worker;
let id = ++MESSAGE_COUNTER;
let 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);
return new Promise((resolve, reject) => {
let 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 via window/utils here as we don't want to include
// this module normally.
let { getMostRecentBrowserWindow } = require("sdk/window/utils");
let { URL, Blob } = getMostRecentBrowserWindow();
let stringifiedFn = createWorkerString(fn);
let blob = new Blob([stringifiedFn]);
let url = URL.createObjectURL(blob);
let worker = new DevToolsWorker(url);
let wrapperFn = data => worker.performTask("workerifiedTask", data);
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()});`;
}
});
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