1 files changed, 91 insertions, 0 deletions
diff --git a/addon-sdk/source/lib/toolkit/require.js b/addon-sdk/source/lib/toolkit/require.js
new file mode 100644
index 000000000..dc3d26ab2
--- /dev/null
+++ b/addon-sdk/source/lib/toolkit/require.js
@@ -0,0 +1,91 @@
+/* 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/. */
+
+const make = (exports, rootURI, components) => {
+  const { Loader: { Loader, Require, Module, main } } =
+        components.utils.import(rootURI + "toolkit/loader.js", {});
+
+  const loader = Loader({
+    id: "toolkit/require",
+    rootURI: rootURI,
+    isNative: true,
+    paths: {
+     "": rootURI,
+     "devtools/": "resource://devtools/"
+    }
+  });
+
+  // Implement require.unload(uri) that can be used to unload
+  // already loaded module which is convinient during development phase.
+  const unload = uri => {
+    delete loader.sandboxes[uri];
+    delete loader.modules[uri];
+  };
+
+  const builtins = new Set(Object.keys(loader.modules));
+
+  // Below we define `require` & `require.resolve` that resolve passed
+  // module id relative to the caller URI. This is not perfect but good
+  // enough for common case & there is always an option to pass absolute
+  // id when that
+  // but presumably well enough to cover
+
+  const require = (id, options={}) => {
+    const { reload, all } = options;
+    const requirerURI = components.stack.caller.filename;
+    const requirer = Module(requirerURI, requirerURI);
+    const require = Require(loader, requirer);
+    if (reload) {
+      // To load JS code into modules, loader uses `mozIJSSubScriptLoader`
+      // which uses startup cache to avoid reading source from the same URI
+      // more than once. Unless we invalidate statup cache changes to a module
+      // won't be reflected even after reload. Therefor we must dispatch an
+      // nsIObserverService notification that causes cache invalidation.
+      // Note: This is not ideal since it destroys whole cache, but since there
+      // is no way to invalidate individual entries, we assume performance hit
+      // during development is acceptable.
+      components.classes["@mozilla.org/observer-service;1"].
+        getService(components.interfaces.nsIObserverService).
+        notifyObservers({}, "startupcache-invalidate", null);
+
+      if (all) {
+        for (let uri of Object.keys(loader.sandboxes)) {
+          unload(uri);
+        }
+      }
+      else {
+        unload(require.resolve(id));
+      }
+    }
+    return require(id);
+  };
+
+  require.resolve = id => {
+    const requirerURI = components.stack.caller.filename;
+    const requirer = Module(requirerURI, requirerURI);
+    return Require(loader, requirer).resolve(id);
+  };
+
+  exports.require = require;
+}
+
+// If loaded in the context of commonjs module, reload as JSM into an
+// exports object.
+if (typeof(require) === "function" && typeof(module) === "object") {
+  require("chrome").Cu.import(module.uri, module.exports);
+}
+// If loaded in the context of JSM make a loader & require and define
+// new symbols as exported ones.
+else if (typeof(__URI__) === "string" && this["Components"]) {
+  const builtin = Object.keys(this);
+  const uri = __URI__.replace("toolkit/require.js", "");
+  make(this, uri, this["Components"]);
+
+  this.EXPORTED_SYMBOLS = Object.
+                            keys(this).
+                            filter($ => builtin.indexOf($) < 0);
+}
+else {
+  throw Error("Loading require.js in this environment isn't supported")
+}