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, 104 insertions, 60 deletions

diff --git a/src/components/script/dom/htmlobjectelement.rs b/src/components/script/dom/htmlobjectelement.rs
index e2c7d16c03d..c020765d431 100644
--- a/src/components/script/dom/htmlobjectelement.rs
+++ b/src/components/script/dom/htmlobjectelement.rs
@@ -2,10 +2,11 @@
  * 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/. */
 
+use dom::attr::AttrMethods;
 use dom::bindings::codegen::BindingDeclarations::HTMLObjectElementBinding;
 use dom::bindings::codegen::InheritTypes::HTMLObjectElementDerived;
 use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLElementCast};
-use dom::bindings::js::JS;
+use dom::bindings::js::{JSRef, Temporary};
 use dom::bindings::error::ErrorResult;
 use dom::document::Document;
 use dom::element::{Element, HTMLObjectElementTypeId};
@@ -41,14 +42,14 @@ impl HTMLObjectElementDerived for EventTarget {
 }
 
 impl HTMLObjectElement {
-    pub fn new_inherited(localName: DOMString, document: JS<Document>) -> HTMLObjectElement {
+    pub fn new_inherited(localName: DOMString, document: &JSRef<Document>) -> HTMLObjectElement {
         HTMLObjectElement {
             htmlelement: HTMLElement::new_inherited(HTMLObjectElementTypeId, localName, document),
         }
     }
 
-    pub fn new(localName: DOMString, document: &JS<Document>) -> JS<HTMLObjectElement> {
-        let element = HTMLObjectElement::new_inherited(localName, document.clone());
+    pub fn new(localName: DOMString, document: &JSRef<Document>) -> Temporary<HTMLObjectElement> {
+        let element = HTMLObjectElement::new_inherited(localName, document);
         Node::reflect_node(~element, document, HTMLObjectElementBinding::Wrap)
     }
 }
@@ -57,15 +58,15 @@ trait ProcessDataURL {
     fn process_data_url(&mut self, image_cache: ImageCacheTask, url: Option<Url>);
 }
 
-impl ProcessDataURL for JS<HTMLObjectElement> {
+impl<'a> ProcessDataURL for JSRef<'a, HTMLObjectElement> {
     // Makes the local `data` member match the status of the `data` attribute and starts
     /// prefetching the image. This method must be called after `data` is changed.
     fn process_data_url(&mut self, image_cache: ImageCacheTask, url: Option<Url>) {
-        let elem: JS<Element> = ElementCast::from(self);
+        let elem: &JSRef<Element> = ElementCast::from_ref(self);
 
         // TODO: support other values
-        match (elem.get_attribute(Null, "type").map(|x| x.get().Value()),
-               elem.get_attribute(Null, "data").map(|x| x.get().Value())) {
+        match (elem.get_attribute(Null, "type").map(|x| x.root().Value()),
+               elem.get_attribute(Null, "data").map(|x| x.root().Value())) {
             (None, Some(uri)) => {
                 if is_image_data(uri) {
                     let data_url = parse_url(uri, url);
@@ -78,177 +79,220 @@ impl ProcessDataURL for JS<HTMLObjectElement> {
     }
 }
 
-impl HTMLObjectElement {
-    pub fn Data(&self) -> DOMString {
+pub trait HTMLObjectElementMethods {
+    fn Data(&self) -> DOMString;
+    fn SetData(&mut self, _data: DOMString) -> ErrorResult;
+    fn Type(&self) -> DOMString;
+    fn SetType(&mut self, _type: DOMString) -> ErrorResult;
+    fn Name(&self) -> DOMString;
+    fn SetName(&mut self, _name: DOMString) -> ErrorResult;
+    fn UseMap(&self) -> DOMString;
+    fn SetUseMap(&mut self, _use_map: DOMString) -> ErrorResult;
+    fn GetForm(&self) -> Option<Temporary<HTMLFormElement>>;
+    fn Width(&self) -> DOMString;
+    fn SetWidth(&mut self, _width: DOMString) -> ErrorResult;
+    fn Height(&self) -> DOMString;
+    fn SetHeight(&mut self, _height: DOMString) -> ErrorResult;
+    fn GetContentDocument(&self) -> Option<Temporary<Document>>;
+    fn GetContentWindow(&self) -> Option<Temporary<Window>>;
+    fn WillValidate(&self) -> bool;
+    fn Validity(&self) -> Temporary<ValidityState>;
+    fn ValidationMessage(&self) -> DOMString;
+    fn CheckValidity(&self) -> bool;
+    fn SetCustomValidity(&mut self, _error: DOMString);
+    fn Align(&self) -> DOMString;
+    fn SetAlign(&mut self, _align: DOMString) -> ErrorResult;
+    fn Archive(&self) -> DOMString;
+    fn SetArchive(&mut self, _archive: DOMString) -> ErrorResult;
+    fn Code(&self) -> DOMString;
+    fn SetCode(&mut self, _code: DOMString) -> ErrorResult;
+    fn Declare(&self) -> bool;
+    fn SetDeclare(&mut self, _declare: bool) -> ErrorResult;
+    fn Hspace(&self) -> u32;
+    fn SetHspace(&mut self, _hspace: u32) -> ErrorResult;
+    fn Standby(&self) -> DOMString;
+    fn SetStandby(&mut self, _standby: DOMString) -> ErrorResult;
+    fn Vspace(&self) -> u32;
+    fn SetVspace(&mut self, _vspace: u32) -> ErrorResult;
+    fn CodeBase(&self) -> DOMString;
+    fn SetCodeBase(&mut self, _codebase: DOMString) -> ErrorResult;
+    fn CodeType(&self) -> DOMString;
+    fn SetCodeType(&mut self, _codetype: DOMString) -> ErrorResult;
+    fn Border(&self) -> DOMString;
+    fn SetBorder(&mut self, _border: DOMString) -> ErrorResult;
+    fn GetSVGDocument(&self) -> Option<Temporary<Document>>;
+}
+
+impl<'a> HTMLObjectElementMethods for JSRef<'a, HTMLObjectElement> {
+    fn Data(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetData(&mut self, _data: DOMString) -> ErrorResult {
+    fn SetData(&mut self, _data: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Type(&self) -> DOMString {
+    fn Type(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetType(&mut self, _type: DOMString) -> ErrorResult {
+    fn SetType(&mut self, _type: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Name(&self) -> DOMString {
+    fn Name(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetName(&mut self, _name: DOMString) -> ErrorResult {
+    fn SetName(&mut self, _name: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn UseMap(&self) -> DOMString {
+    fn UseMap(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetUseMap(&mut self, _use_map: DOMString) -> ErrorResult {
+    fn SetUseMap(&mut self, _use_map: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn GetForm(&self) -> Option<JS<HTMLFormElement>> {
+    fn GetForm(&self) -> Option<Temporary<HTMLFormElement>> {
         None
     }
 
-    pub fn Width(&self) -> DOMString {
+    fn Width(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetWidth(&mut self, _width: DOMString) -> ErrorResult {
+    fn SetWidth(&mut self, _width: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Height(&self) -> DOMString {
+    fn Height(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetHeight(&mut self, _height: DOMString) -> ErrorResult {
+    fn SetHeight(&mut self, _height: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn GetContentDocument(&self) -> Option<JS<Document>> {
+    fn GetContentDocument(&self) -> Option<Temporary<Document>> {
         None
     }
 
-    pub fn GetContentWindow(&self) -> Option<JS<Window>> {
+    fn GetContentWindow(&self) -> Option<Temporary<Window>> {
         None
     }
 
-    pub fn WillValidate(&self) -> bool {
+    fn WillValidate(&self) -> bool {
         false
     }
 
-    pub fn Validity(&self) -> JS<ValidityState> {
-        let doc = self.htmlelement.element.node.owner_doc();
-        let doc = doc.get();
-        ValidityState::new(&doc.window)
+    fn Validity(&self) -> Temporary<ValidityState> {
+        let window = window_from_node(self).root();
+        ValidityState::new(&*window)
     }
 
-    pub fn ValidationMessage(&self) -> DOMString {
+    fn ValidationMessage(&self) -> DOMString {
         ~""
     }
 
-    pub fn CheckValidity(&self) -> bool {
+    fn CheckValidity(&self) -> bool {
         false
     }
 
-    pub fn SetCustomValidity(&mut self, _error: DOMString) {
+    fn SetCustomValidity(&mut self, _error: DOMString) {
     }
 
-    pub fn Align(&self) -> DOMString {
+    fn Align(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetAlign(&mut self, _align: DOMString) -> ErrorResult {
+    fn SetAlign(&mut self, _align: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Archive(&self) -> DOMString {
+    fn Archive(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetArchive(&mut self, _archive: DOMString) -> ErrorResult {
+    fn SetArchive(&mut self, _archive: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Code(&self) -> DOMString {
+    fn Code(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetCode(&mut self, _code: DOMString) -> ErrorResult {
+    fn SetCode(&mut self, _code: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Declare(&self) -> bool {
+    fn Declare(&self) -> bool {
         false
     }
 
-    pub fn SetDeclare(&mut self, _declare: bool) -> ErrorResult {
+    fn SetDeclare(&mut self, _declare: bool) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Hspace(&self) -> u32 {
+    fn Hspace(&self) -> u32 {
         0
     }
 
-    pub fn SetHspace(&mut self, _hspace: u32) -> ErrorResult {
+    fn SetHspace(&mut self, _hspace: u32) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Standby(&self) -> DOMString {
+    fn Standby(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetStandby(&mut self, _standby: DOMString) -> ErrorResult {
+    fn SetStandby(&mut self, _standby: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Vspace(&self) -> u32 {
+    fn Vspace(&self) -> u32 {
         0
     }
 
-    pub fn SetVspace(&mut self, _vspace: u32) -> ErrorResult {
+    fn SetVspace(&mut self, _vspace: u32) -> ErrorResult {
         Ok(())
     }
 
-    pub fn CodeBase(&self) -> DOMString {
+    fn CodeBase(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetCodeBase(&mut self, _codebase: DOMString) -> ErrorResult {
+    fn SetCodeBase(&mut self, _codebase: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn CodeType(&self) -> DOMString {
+    fn CodeType(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetCodeType(&mut self, _codetype: DOMString) -> ErrorResult {
+    fn SetCodeType(&mut self, _codetype: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn Border(&self) -> DOMString {
+    fn Border(&self) -> DOMString {
         ~""
     }
 
-    pub fn SetBorder(&mut self, _border: DOMString) -> ErrorResult {
+    fn SetBorder(&mut self, _border: DOMString) -> ErrorResult {
         Ok(())
     }
 
-    pub fn GetSVGDocument(&self) -> Option<JS<Document>> {
+    fn GetSVGDocument(&self) -> Option<Temporary<Document>> {
         None
     }
 }
 
-impl VirtualMethods for JS<HTMLObjectElement> {
-    fn super_type(&self) -> Option<~VirtualMethods:> {
-        let htmlelement: JS<HTMLElement> = HTMLElementCast::from(self);
-        Some(~htmlelement as ~VirtualMethods:)
+impl<'a> VirtualMethods for JSRef<'a, HTMLObjectElement> {
+    fn super_type<'a>(&'a mut self) -> Option<&'a mut VirtualMethods:> {
+        let htmlelement: &mut JSRef<HTMLElement> = HTMLElementCast::from_mut_ref(self);
+        Some(htmlelement as &mut VirtualMethods:)
     }
 
     fn after_set_attr(&mut self, name: DOMString, value: DOMString) {
@@ -258,9 +302,9 @@ impl VirtualMethods for JS<HTMLObjectElement> {
         }
 
         if "data" == name {
-            let window = window_from_node(self);
-            let url = Some(window.get().get_url());
-            self.process_data_url(window.get().image_cache_task.clone(), url);
+            let window = window_from_node(self).root();
+            let url = Some(window.deref().get_url());
+            self.process_data_url(window.deref().image_cache_task.clone(), url);
         }
     }
 }