Bug 566846 - Make sure the engine knows that wrapper iterators are real iterators. r=gal

js/src/xpconnect/src/XPCWrapper.cpp

@@ -154,14 +154,28 @@ IteratorNext(JSContext *cx, uintN argc, jsval *vp)
   return JS_TRUE;
 }
 
-static JSClass IteratorClass = {
-  "XOW iterator", JSCLASS_HAS_RESERVED_SLOTS(3),
-  JS_PropertyStub, JS_PropertyStub,
-  JS_PropertyStub, JS_PropertyStub,
-  JS_EnumerateStub, JS_ResolveStub,
-  JS_ConvertStub, IteratorFinalize,
+static JSObject *
+IteratorIterator(JSContext *, JSObject *obj, JSBool)
+{
+  return obj;
+}
 
-  JSCLASS_NO_OPTIONAL_MEMBERS
+static JSExtendedClass IteratorClass = {
+  { "Wrapper iterator",
+    JSCLASS_HAS_RESERVED_SLOTS(3) | JSCLASS_IS_EXTENDED,
+    JS_PropertyStub, JS_PropertyStub,
+    JS_PropertyStub, JS_PropertyStub,
+    JS_EnumerateStub, JS_ResolveStub,
+    JS_ConvertStub, IteratorFinalize,
+
+    JSCLASS_NO_OPTIONAL_MEMBERS
+  },
+
+  nsnull,             // equality
+  nsnull, nsnull,     // innerObject/outerObject
+  IteratorIterator,
+  nsnull,             // wrappedObject
+  JSCLASS_NO_RESERVED_MEMBERS
 };
 
 JSBool
@@ -317,7 +331,7 @@ CreateIteratorObj(JSContext *cx, JSObject *tempWrapper,
   // delegates (via the __proto__ link) to the wrapper.
 
   JSObject *iterObj =
-    JS_NewObjectWithGivenProto(cx, &IteratorClass, tempWrapper, wrapperObj);
+    JS_NewObjectWithGivenProto(cx, &IteratorClass.base, tempWrapper, wrapperObj);
   if (!iterObj) {
     return nsnull;
   }
@@ -380,7 +394,7 @@ JSObject *
 CreateSimpleIterator(JSContext *cx, JSObject *scope, JSBool keysonly,
                      JSObject *propertyContainer)
 {
-  JSObject *iterObj = JS_NewObjectWithGivenProto(cx, &IteratorClass,
+  JSObject *iterObj = JS_NewObjectWithGivenProto(cx, &IteratorClass.base,
                                                  propertyContainer, scope);
   if (!iterObj) {
     return nsnull;

js/src/xpconnect/tests/mochitest/test_wrappers.html

@@ -47,6 +47,18 @@
        xpcnw_expected.sort().toString(),
        'enumeration over XPCNWs walks the prototype chain');
 
+    var for_each_expected = [];
+    for each (let i in new XPCNativeWrapper(location))
+        for_each_expected.push(typeof i);
+
+    var for_each_answer = [];
+    for each (let i in Iterator(new XPCNativeWrapper(location)))
+        for_each_answer.push(typeof i);
+
+    is(for_each_answer.sort().toString(),
+       for_each_expected.sort().toString(),
+       'wrapper iterators are properly iterators');
+
     let sjow_answer = [];
     let (obj = { a: 3, next:1 }) {
         for (let i in XPCSafeJSObjectWrapper({ __proto__: obj}))