Use Cell for Reflector::object.

src/components/script/dom/bindings/codegen/CodegenRust.py

@@ -1838,7 +1838,7 @@ class CGWrapMethod(CGAbstractMethod):
 
 %s
 
-  raw.mut_reflector().set_jsobject(obj);
+  raw.reflector().set_jsobject(obj);
 
   return raw;""" % CreateBindingJSObject(self.descriptor, "scope")
         else:
@@ -1848,7 +1848,7 @@ class CGWrapMethod(CGAbstractMethod):
     let proto = GetProtoObject(aCx, obj, obj);
     JS_SetPrototype(aCx, obj, proto);
   });
-  raw.mut_reflector().set_jsobject(obj);
+  raw.reflector().set_jsobject(obj);
   return raw;""" % CreateBindingJSObject(self.descriptor)
 
 

src/components/script/dom/bindings/utils.rs

@@ -14,8 +14,9 @@ use servo_util::str::DOMString;
 use collections::hashmap::HashMap;
 use libc;
 use libc::c_uint;
-use std::mem;
+use std::cell::Cell;
 use std::cmp::Eq;
+use std::mem;
 use std::ptr;
 use std::ptr::null;
 use std::slice;
@@ -415,31 +416,33 @@ pub fn reflect_dom_object<T: Reflectable>
 #[allow(raw_pointer_deriving)]
 #[deriving(Eq)]
 pub struct Reflector {
-    object: *mut JSObject,
+    object: Cell<*mut JSObject>,
 }
 
 impl Reflector {
     #[inline]
     pub fn get_jsobject(&self) -> *mut JSObject {
-        self.object
+        self.object.get()
     }
 
-    pub fn set_jsobject(&mut self, object: *mut JSObject) {
-        assert!(self.object.is_null());
+    pub fn set_jsobject(&self, object: *mut JSObject) {
+        assert!(self.object.get().is_null());
         assert!(object.is_not_null());
-        self.object = object;
+        self.object.set(object);
     }
 
     /// Return a pointer to the memory location at which the JS reflector object is stored.
     /// Used by Temporary values to root the reflector, as required by the JSAPI rooting
     /// APIs.
-    pub fn rootable<'a>(&'a mut self) -> &'a mut *mut JSObject {
-        &mut self.object
+    pub fn rootable(&self) -> *mut *mut JSObject {
+        &self.object as *Cell<*mut JSObject>
+                     as *mut Cell<*mut JSObject>
+                     as *mut *mut JSObject
     }
 
     pub fn new() -> Reflector {
         Reflector {
-            object: ptr::mut_null(),
+            object: Cell::new(ptr::mut_null()),
         }
     }
 }

src/components/script/dom/xmlhttprequest.rs

@@ -622,14 +622,14 @@ impl<'a> PrivateXMLHttpRequestHelpers for JSRef<'a, XMLHttpRequest> {
     unsafe fn to_trusted(&mut self) -> TrustedXHRAddress {
         assert!(self.pinned == false);
         self.pinned = true;
-        JS_AddObjectRoot(self.global.root().get_cx(), self.mut_reflector().rootable());
+        JS_AddObjectRoot(self.global.root().get_cx(), self.reflector().rootable());
         TrustedXHRAddress(self.deref() as *XMLHttpRequest as *libc::c_void)
     }
 
     fn release(&mut self) {
         assert!(self.pinned);
         unsafe {
-            JS_RemoveObjectRoot(self.global.root().get_cx(), self.mut_reflector().rootable());
+            JS_RemoveObjectRoot(self.global.root().get_cx(), self.reflector().rootable());
         }
         self.pinned = false;
     }