1 files changed, 33 insertions, 0 deletions
diff --git a/js/xpconnect/loader/ComponentUtils.sys.mjs b/js/xpconnect/loader/ComponentUtils.sys.mjs
new file mode 100644
index 0000000000..cfffb96ef7
--- /dev/null
+++ b/js/xpconnect/loader/ComponentUtils.sys.mjs
@@ -0,0 +1,33 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et filetype=javascript
+ * 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/. */
+
+/**
+ * Deprecated utilities for JavaScript components loaded by the JS component
+ * loader.
+ */
+
+const nsIFactoryQI = ChromeUtils.generateQI(["nsIFactory"]);
+
+export var ComponentUtils = {
+  /**
+   * Generates a singleton nsIFactory implementation that can be used as
+   * an argument to nsIComponentRegistrar.registerFactory.
+   * @param aServiceConstructor
+   *        Constructor function of the component.
+   */
+  generateSingletonFactory(aServiceConstructor) {
+    return {
+      _instance: null,
+      createInstance(aIID) {
+        if (this._instance === null) {
+          this._instance = new aServiceConstructor();
+        }
+        return this._instance.QueryInterface(aIID);
+      },
+      QueryInterface: nsIFactoryQI,
+    };
+  },
+};