1 files changed, 161 insertions, 0 deletions
diff --git a/toolkit/components/workerloader/require.js b/toolkit/components/workerloader/require.js
new file mode 100644
index 000000000..223132f7e
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+++ b/toolkit/components/workerloader/require.js
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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/. */
+
+
+/**
+ * Implementation of a CommonJS module loader for workers.
+ *
+ * Use:
+ * // in the .js file loaded by the constructor of the worker
+ * importScripts("resource://gre/modules/workers/require.js");
+ * let module = require("resource://gre/modules/worker/myModule.js");
+ *
+ * // in myModule.js
+ * // Load dependencies
+ * let SimpleTest = require("resource://gre/modules/workers/SimpleTest.js");
+ * let Logger = require("resource://gre/modules/workers/Logger.js");
+ *
+ * // Define things that will not be exported
+ * let someValue = // ...
+ *
+ * // Export symbols
+ * exports.foo = // ...
+ * exports.bar = // ...
+ *
+ *
+ * Note #1:
+ * Properties |fileName| and |stack| of errors triggered from a module
+ * contain file names that do not correspond to human-readable module paths.
+ * Human readers should rather use properties |moduleName| and |moduleStack|.
+ *
+ * Note #2:
+ * The current version of |require()| only accepts absolute URIs.
+ *
+ * Note #3:
+ * By opposition to some other module loader implementations, this module
+ * loader does not enforce separation of global objects. Consequently, if
+ * a module modifies a global object (e.g. |String.prototype|), all other
+ * modules in the same worker may be affected.
+ */
+
+
+(function(exports) {
+  "use strict";
+
+  if (exports.require) {
+    // Avoid double-imports
+    return;
+  }
+
+  // Simple implementation of |require|
+  let require = (function() {
+
+    /**
+     * Mapping from module paths to module exports.
+     *
+     * @keys {string} The absolute path to a module.
+     * @values {object} The |exports| objects for that module.
+     */
+    let modules = new Map();
+
+    /**
+     * A human-readable version of |stack|.
+     *
+     * @type {string}
+     */
+    Object.defineProperty(Error.prototype, "moduleStack",
+    {
+      get: function() {
+        return this.stack;
+      }
+    });
+    /**
+     * A human-readable version of |fileName|.
+     *
+     * @type {string}
+     */
+    Object.defineProperty(Error.prototype, "moduleName",
+    {
+      get: function() {
+        let match = this.stack.match(/\@(.*):.*:/);
+        if (match) {
+          return match[1];
+        }
+        return "(unknown module)";
+      }
+    });
+
+    /**
+     * Import a module
+     *
+     * @param {string} path The path to the module.
+     * @return {*} An object containing the properties exported by the module.
+     */
+    return function require(path) {
+      if (typeof path != "string" || path.indexOf("://") == -1) {
+        throw new TypeError("The argument to require() must be a string uri, got " + path);
+      }
+      // Automatically add ".js" if there is no extension
+      let uri;
+      if (path.lastIndexOf(".") <= path.lastIndexOf("/")) {
+        uri = path + ".js";
+      } else {
+        uri = path;
+      }
+
+      // Exports provided by the module
+      let exports = Object.create(null);
+
+      // Identification of the module
+      let module = {
+        id: path,
+        uri: uri,
+        exports: exports
+      };
+
+      // Make module available immediately
+      // (necessary in case of circular dependencies)
+      if (modules.has(path)) {
+        return modules.get(path).exports;
+      }
+      modules.set(path, module);
+
+      try {
+        // Load source of module, synchronously
+        let xhr = new XMLHttpRequest();
+        xhr.open("GET", uri, false);
+        xhr.responseType = "text";
+        xhr.send();
+
+
+        let source = xhr.responseText;
+        if (source == "") {
+          // There doesn't seem to be a better way to detect that the file couldn't be found
+          throw new Error("Could not find module " + path);
+        }
+        let code = new Function("exports", "require", "module",
+          source + "\n//# sourceURL=" + uri + "\n"
+        );
+        code(exports, require, module);
+      } catch (ex) {
+        // Module loading has failed, exports should not be made available
+        // after all.
+        modules.delete(path);
+        throw ex;
+      }
+
+      Object.freeze(module.exports);
+      Object.freeze(module);
+      return module.exports;
+    };
+  })();
+
+  Object.freeze(require);
+
+  Object.defineProperty(exports, "require", {
+    value: require,
+    enumerable: true,
+    configurable: false
+  });
+})(this);