1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/components/workerloader/require.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,243 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +
1.9 +/**
1.10 + * Implementation of a CommonJS module loader for workers.
1.11 + *
1.12 + * Use:
1.13 + * // in the .js file loaded by the constructor of the worker
1.14 + * importScripts("resource://gre/modules/workers/require.js");
1.15 + * let module = require("resource://gre/modules/worker/myModule.js");
1.16 + *
1.17 + * // in myModule.js
1.18 + * // Load dependencies
1.19 + * let SimpleTest = require("resource://gre/modules/workers/SimpleTest.js");
1.20 + * let Logger = require("resource://gre/modules/workers/Logger.js");
1.21 + *
1.22 + * // Define things that will not be exported
1.23 + * let someValue = // ...
1.24 + *
1.25 + * // Export symbols
1.26 + * exports.foo = // ...
1.27 + * exports.bar = // ...
1.28 + *
1.29 + *
1.30 + * Note #1:
1.31 + * Properties |fileName| and |stack| of errors triggered from a module
1.32 + * contain file names that do not correspond to human-readable module paths.
1.33 + * Human readers should rather use properties |moduleName| and |moduleStack|.
1.34 + *
1.35 + * Note #2:
1.36 + * The current version of |require()| only accepts absolute URIs.
1.37 + *
1.38 + * Note #3:
1.39 + * By opposition to some other module loader implementations, this module
1.40 + * loader does not enforce separation of global objects. Consequently, if
1.41 + * a module modifies a global object (e.g. |String.prototype|), all other
1.42 + * modules in the same worker may be affected.
1.43 + */
1.44 +
1.45 +
1.46 +(function(exports) {
1.47 + "use strict";
1.48 +
1.49 + if (exports.require) {
1.50 + // Avoid double-imports
1.51 + return;
1.52 + }
1.53 +
1.54 + // Simple implementation of |require|
1.55 + let require = (function() {
1.56 +
1.57 + /**
1.58 + * Mapping from module paths to module exports.
1.59 + *
1.60 + * @keys {string} The absolute path to a module.
1.61 + * @values {object} The |exports| objects for that module.
1.62 + */
1.63 + let modules = new Map();
1.64 +
1.65 + /**
1.66 + * Mapping from object urls to module paths.
1.67 + */
1.68 + let paths = {
1.69 + /**
1.70 + * @keys {string} The object url holding a module.
1.71 + * @values {string} The absolute path to that module.
1.72 + */
1.73 + _map: new Map(),
1.74 + /**
1.75 + * A regexp that may be used to search for all mapped paths.
1.76 + */
1.77 + get regexp() {
1.78 + if (this._regexp) {
1.79 + return this._regexp;
1.80 + }
1.81 + let objectURLs = [];
1.82 + for (let [objectURL, _] of this._map) {
1.83 + objectURLs.push(objectURL);
1.84 + }
1.85 + return this._regexp = new RegExp(objectURLs.join("|"), "g");
1.86 + },
1.87 + _regexp: null,
1.88 + /**
1.89 + * Add a mapping from an object url to a path.
1.90 + */
1.91 + set: function(url, path) {
1.92 + this._regexp = null; // invalidate regexp
1.93 + this._map.set(url, path);
1.94 + },
1.95 + /**
1.96 + * Get a mapping from an object url to a path.
1.97 + */
1.98 + get: function(url) {
1.99 + return this._map.get(url);
1.100 + },
1.101 + /**
1.102 + * Transform a string by replacing all the instances of objectURLs
1.103 + * appearing in that string with the corresponding module path.
1.104 + *
1.105 + * This is used typically to translate exception stacks.
1.106 + *
1.107 + * @param {string} source A source string.
1.108 + * @return {string} The same string as |source|, in which every occurrence
1.109 + * of an objectURL registered in this object has been replaced with the
1.110 + * corresponding module path.
1.111 + */
1.112 + substitute: function(source) {
1.113 + let map = this._map;
1.114 + return source.replace(this.regexp, function(url) {
1.115 + return map.get(url) || url;
1.116 + }, "g");
1.117 + }
1.118 + };
1.119 +
1.120 + /**
1.121 + * A human-readable version of |stack|.
1.122 + *
1.123 + * @type {string}
1.124 + */
1.125 + Object.defineProperty(Error.prototype, "moduleStack",
1.126 + {
1.127 + get: function() {
1.128 + return paths.substitute(this.stack);
1.129 + }
1.130 + });
1.131 + /**
1.132 + * A human-readable version of |fileName|.
1.133 + *
1.134 + * @type {string}
1.135 + */
1.136 + Object.defineProperty(Error.prototype, "moduleName",
1.137 + {
1.138 + get: function() {
1.139 + return paths.substitute(this.fileName);
1.140 + }
1.141 + });
1.142 +
1.143 + /**
1.144 + * Import a module
1.145 + *
1.146 + * @param {string} path The path to the module.
1.147 + * @return {*} An object containing the properties exported by the module.
1.148 + */
1.149 + return function require(path) {
1.150 + if (typeof path != "string" || path.indexOf("://") == -1) {
1.151 + throw new TypeError("The argument to require() must be a string uri, got " + path);
1.152 + }
1.153 + // Automatically add ".js" if there is no extension
1.154 + let uri;
1.155 + if (path.lastIndexOf(".") <= path.lastIndexOf("/")) {
1.156 + uri = path + ".js";
1.157 + } else {
1.158 + uri = path;
1.159 + }
1.160 +
1.161 + // Exports provided by the module
1.162 + let exports = Object.create(null);
1.163 +
1.164 + // Identification of the module
1.165 + let module = {
1.166 + id: path,
1.167 + uri: uri,
1.168 + exports: exports
1.169 + };
1.170 +
1.171 + // Make module available immediately
1.172 + // (necessary in case of circular dependencies)
1.173 + if (modules.has(path)) {
1.174 + return modules.get(path).exports;
1.175 + }
1.176 + modules.set(path, module);
1.177 +
1.178 + let name = ":" + path;
1.179 + let objectURL;
1.180 + try {
1.181 + // Load source of module, synchronously
1.182 + let xhr = new XMLHttpRequest();
1.183 + xhr.open("GET", uri, false);
1.184 + xhr.responseType = "text";
1.185 + xhr.send();
1.186 +
1.187 +
1.188 + let source = xhr.responseText;
1.189 + if (source == "") {
1.190 + // There doesn't seem to be a better way to detect that the file couldn't be found
1.191 + throw new Error("Could not find module " + path);
1.192 + }
1.193 + // From the source, build a function and an object URL. We
1.194 + // avoid any newline at the start of the file to ensure that
1.195 + // we do not mess up with line numbers. However, using object URLs
1.196 + // messes up with stack traces in instances of Error().
1.197 + source = "require._tmpModules[\"" + name + "\"] = " +
1.198 + "function(exports, require, module) {" +
1.199 + source +
1.200 + "\n}\n";
1.201 + let blob = new Blob(
1.202 + [
1.203 + (new TextEncoder()).encode(source)
1.204 + ], {
1.205 + type: "application/javascript"
1.206 + });
1.207 + objectURL = URL.createObjectURL(blob);
1.208 + paths.set(objectURL, path);
1.209 + importScripts(objectURL);
1.210 + require._tmpModules[name].call(null, exports, require, module);
1.211 +
1.212 + } catch (ex) {
1.213 + // Module loading has failed, exports should not be made available
1.214 + // after all.
1.215 + modules.delete(path);
1.216 + throw ex;
1.217 + } finally {
1.218 + if (objectURL) {
1.219 + // Clean up the object url as soon as possible. It will not be needed.
1.220 + URL.revokeObjectURL(objectURL);
1.221 + }
1.222 + delete require._tmpModules[name];
1.223 + }
1.224 +
1.225 + Object.freeze(module.exports);
1.226 + Object.freeze(module);
1.227 + return module.exports;
1.228 + };
1.229 + })();
1.230 +
1.231 + /**
1.232 + * An object used to hold temporarily the module constructors
1.233 + * while they are being loaded.
1.234 + *
1.235 + * @keys {string} The path to the module, prefixed with ":".
1.236 + * @values {function} A function wrapping the module.
1.237 + */
1.238 + require._tmpModules = Object.create(null);
1.239 + Object.freeze(require);
1.240 +
1.241 + Object.defineProperty(exports, "require", {
1.242 + value: require,
1.243 + enumerable: true,
1.244 + configurable: false
1.245 + });
1.246 +})(this);
