Bug 849730 - Let objectClassIs through for COWs. r=mrbkap

js/xpconnect/tests/unit/test_bug849730.js

@@ -0,0 +1,7 @@
+const Cu = Components.utils;
+
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  sb.arr = [3, 4];
+  do_check_true(Cu.evalInSandbox('Array.isArray(arr);', sb));
+}

js/xpconnect/tests/unit/xpcshell.ini

@@ -16,6 +16,7 @@ tail =
 [test_bug805807.js]
 [test_bug809652.js]
 [test_bug845201.js]
+[test_bug849730.js]
 [test_bug_442086.js]
 [test_file.js]
 [test_blob.js]

js/xpconnect/wrappers/ChromeObjectWrapper.cpp

@@ -147,6 +147,16 @@ ChromeObjectWrapper::get(JSContext *cx, JSObject *wrapper, JSObject *receiver,
     return js::GetGeneric(cx, wrapperProto, receiver, id, vp);
 }
 
+// SecurityWrapper categorically returns false for objectClassIs, but the
+// contacts API depends on Array.isArray returning true for COW-implemented
+// contacts. This isn't really ideal, but make it work for now.
+bool
+ChromeObjectWrapper::objectClassIs(JSObject *obj, js::ESClassValue classValue,
+                                   JSContext *cx)
+{
+  return CrossCompartmentWrapper::objectClassIs(obj, classValue, cx);
+}
+
 // This mechanism isn't ideal because we end up calling enter() on the base class
 // twice (once during enter() here and once during the trap itself), and policy
 // enforcement or COWs isn't cheap. But it results in the cleanest code, and this

js/xpconnect/wrappers/ChromeObjectWrapper.h

@@ -37,6 +37,9 @@ class ChromeObjectWrapper : public ChromeObjectWrapperBase
     virtual bool get(JSContext *cx, JSObject *wrapper, JSObject *receiver,
                      jsid id, js::Value *vp) MOZ_OVERRIDE;
 
+    virtual bool objectClassIs(JSObject *obj, js::ESClassValue classValue,
+                               JSContext *cx) MOZ_OVERRIDE;
+
     virtual bool enter(JSContext *cx, JSObject *wrapper, jsid id,
                        js::Wrapper::Action act, bool *bp) MOZ_OVERRIDE;