1 files changed, 63 insertions, 0 deletions
diff --git a/tools/addon-sdk-1.7/packages/api-utils/lib/unload.js b/tools/addon-sdk-1.7/packages/api-utils/lib/unload.js
new file mode 100644
index 0000000..aba5923
--- /dev/null
+++ b/tools/addon-sdk-1.7/packages/api-utils/lib/unload.js
@@ -0,0 +1,63 @@
+/* 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/. */
+
+// Parts of this module were taken from narwhal:
+//
+// http://narwhaljs.org
+
+var observers = [];
+var unloaders = [];
+
+var when = exports.when = function when(observer) {
+  if (observers.indexOf(observer) != -1)
+    return;
+  observers.unshift(observer);
+};
+
+var send = exports.send = function send(reason, onError) {
+  onError = onError || console.exception;
+  observers.forEach(function (observer) {
+    try {
+      observer(reason);
+    } catch (e) {
+      onError(e);
+    }
+  });
+};
+
+var ensure = exports.ensure = function ensure(obj, destructorName) {
+  if (!destructorName)
+    destructorName = "unload";
+  if (!(destructorName in obj))
+    throw new Error("object has no '" + destructorName + "' property");
+
+  let called = false;
+  let originalDestructor = obj[destructorName];
+
+  function unloadWrapper(reason) {
+    if (!called) {
+      called = true;
+      let index = unloaders.indexOf(unloadWrapper);
+      if (index == -1)
+        throw new Error("internal error: unloader not found");
+      unloaders.splice(index, 1);
+      originalDestructor.call(obj, reason);
+      originalDestructor = null;
+      destructorName = null;
+      obj = null;
+    }
+  };
+
+  unloaders.push(unloadWrapper);
+
+  obj[destructorName] = unloadWrapper;
+};
+
+when(
+  function(reason) {
+    unloaders.slice().forEach(
+      function(unloadWrapper) {
+        unloadWrapper(reason);
+      });
+  });