auto merge of #2101 : jdm/servo/newroot_rebase, r=Ms2ger

As described in #1764, this strategy uses the following properties:
* DOM members are `JS<T>` types. These cannot be used with being explicitly rooted, but they are required for compiler-derived trace hooks.
* Methods that take DOM type arguments receive `&[mut] JSRef<T>`. These are rooted value references that are cloneable but cannot escape.
* Methods that return DOM values use `Unrooted<T>`. These are values that may or may not be rooted elsewhere, but callers must root them in order to interact with them in any way. One unsoundness hole exists - `Unrooted` values must be rooted ASAP, or there exists the danger that JSAPI calls could be made that could cause the underlying JS value to be GCed.
* All methods are implemented on `JSRef<T>`, enforcing the requirement that all DOM values are rooted for the duration of a method call (with a few exceptions for layout-related code, which cannot root values and therefore interacts with `JS<T>` and `&T` values - this is safe under the assumption that layout code interacts with DOM nodes that are in the tree, therefore rooted, and does not run concurrently with content code)

1 files changed, 66 insertions, 34 deletions

diff --git a/src/components/script/dom/htmltablecellelement.rs b/src/components/script/dom/htmltablecellelement.rs
index b00c1d78fcd..d03e2d83d72 100644
--- a/src/components/script/dom/htmltablecellelement.rs
+++ b/src/components/script/dom/htmltablecellelement.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::InheritTypes::HTMLTableCellElementDerived;
-use dom::bindings::js::JS;
+use dom::bindings::js::JSRef;
 use dom::bindings::error::ErrorResult;
 use dom::document::Document;
 use dom::element::{ElementTypeId, HTMLTableDataCellElementTypeId, HTMLTableHeaderCellElementTypeId};
@@ -28,132 +28,164 @@ impl HTMLTableCellElementDerived for EventTarget {
 }
 
 impl HTMLTableCellElement {
-    pub fn new_inherited(type_id: ElementTypeId, tag_name: DOMString, document: JS<Document>) -> HTMLTableCellElement {
+    pub fn new_inherited(type_id: ElementTypeId, tag_name: DOMString, document: &JSRef<Document>) -> HTMLTableCellElement {
         HTMLTableCellElement {
             htmlelement: HTMLElement::new_inherited(type_id, tag_name, document)
         }
     }
 }
 
-impl HTMLTableCellElement {
-    pub fn ColSpan(&self) -> u32 {
+pub trait HTMLTableCellElementMethods {
+    fn ColSpan(&self) -> u32;
+    fn SetColSpan(&self, _col_span: u32) -> ErrorResult;
+    fn RowSpan(&self) -> u32;
+    fn SetRowSpan(&self, _col_span: u32) -> ErrorResult;
+    fn Headers(&self) -> DOMString;
+    fn SetHeaders(&self, _headers: DOMString) -> ErrorResult;
+    fn CellIndex(&self) -> i32;
+    fn GetCellIndex(&self, _cell_index: i32) -> ErrorResult;
+    fn Abbr(&self) -> DOMString;
+    fn SetAbbr(&self, _abbr: DOMString) -> ErrorResult;
+    fn Scope(&self) -> DOMString;
+    fn SetScope(&self, _abbr: DOMString) -> ErrorResult;
+    fn Align(&self) -> DOMString;
+    fn SetAlign(&self, _align: DOMString) -> ErrorResult;
+    fn Axis(&self) -> DOMString;
+    fn SetAxis(&self, _axis: DOMString) -> ErrorResult;
+    fn Height(&self) -> DOMString;
+    fn SetHeight(&self, _height: DOMString) -> ErrorResult;
+    fn Width(&self) -> DOMString;
+    fn SetWidth(&self, _width: DOMString) -> ErrorResult;
+    fn Ch(&self) -> DOMString;
+    fn SetCh(&self, _ch: DOMString) -> ErrorResult;
+    fn ChOff(&self) -> DOMString;
+    fn SetChOff(&self, _ch_off: DOMString) -> ErrorResult;
+    fn NoWrap(&self) -> bool;
+    fn SetNoWrap(&self, _no_wrap: bool) -> ErrorResult;
+    fn VAlign(&self) -> DOMString;
+    fn SetVAlign(&self, _valign: DOMString) -> ErrorResult;
+    fn BgColor(&self) -> DOMString;
+    fn SetBgColor(&self, _bg_color: DOMString) -> ErrorResult;
+}
+
+impl<'a> HTMLTableCellElementMethods for JSRef<'a, HTMLTableCellElement> {
+    fn ColSpan(&self) -> u32 {
         0
     }
 
-    pub fn SetColSpan(&self, _col_span: u32) -> ErrorResult {
+    fn SetColSpan(&self, _col_span: u32) -> ErrorResult {
         Ok(())
     }
 
-    pub fn RowSpan(&self) -> u32 {
+    fn RowSpan(&self) -> u32 {
         0
     }
 
-    pub fn SetRowSpan(&self, _col_span: u32) -> ErrorResult {
+    fn SetRowSpan(&self, _col_span: u32) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Headers(&self) -> DOMString {
+    fn Headers(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetHeaders(&self, _headers: DOMString) -> ErrorResult {
+    fn SetHeaders(&self, _headers: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn CellIndex(&self) -> i32 {
+    fn CellIndex(&self) -> i32 {
         0
     }
 
-    pub fn GetCellIndex(&self, _cell_index: i32) -> ErrorResult {
+    fn GetCellIndex(&self, _cell_index: i32) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Abbr(&self) -> DOMString {
+    fn Abbr(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetAbbr(&self, _abbr: DOMString) -> ErrorResult {
+    fn SetAbbr(&self, _abbr: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Scope(&self) -> DOMString {
+    fn Scope(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetScope(&self, _abbr: DOMString) -> ErrorResult {
+    fn SetScope(&self, _abbr: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Align(&self) -> DOMString {
+    fn Align(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetAlign(&self, _align: DOMString) -> ErrorResult {
+    fn SetAlign(&self, _align: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Axis(&self) -> DOMString {
+    fn Axis(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetAxis(&self, _axis: DOMString) -> ErrorResult {
+    fn SetAxis(&self, _axis: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Height(&self) -> DOMString {
+    fn Height(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetHeight(&self, _height: DOMString) -> ErrorResult {
+    fn SetHeight(&self, _height: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Width(&self) -> DOMString {
+    fn Width(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetWidth(&self, _width: DOMString) -> ErrorResult {
+    fn SetWidth(&self, _width: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Ch(&self) -> DOMString {
+    fn Ch(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetCh(&self, _ch: DOMString) -> ErrorResult {
+    fn SetCh(&self, _ch: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn ChOff(&self) -> DOMString {
+    fn ChOff(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetChOff(&self, _ch_off: DOMString) -> ErrorResult {
+    fn SetChOff(&self, _ch_off: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn NoWrap(&self) -> bool {
+    fn NoWrap(&self) -> bool {
         false
     }
 
-    pub fn SetNoWrap(&self, _no_wrap: bool) -> ErrorResult {
+    fn SetNoWrap(&self, _no_wrap: bool) -> ErrorResult {
         Ok(())
     }
 
-    pub fn VAlign(&self) -> DOMString {
+    fn VAlign(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetVAlign(&self, _valign: DOMString) -> ErrorResult {
+    fn SetVAlign(&self, _valign: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn BgColor(&self) -> DOMString {
+    fn BgColor(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetBgColor(&self, _bg_color: DOMString) -> ErrorResult {
+    fn SetBgColor(&self, _bg_color: DOMString) -> ErrorResult {
         Ok(())
     }
 }
-