Remove the 'static lifetime parameters from TElement methods

This improves the static correctness of layout's use of DOM nodes.

Fixes #2595.

components/layout/construct.rs

@@ -1077,9 +1077,9 @@ impl<'ln> NodeUtils for ThreadSafeLayoutNode<'ln> {
 }
 
 /// Methods for interacting with HTMLObjectElement nodes
-trait ObjectElement {
+trait ObjectElement<'a> {
     /// Returns None if this node is not matching attributes.
-    fn get_type_and_data(&self) -> (Option<&'static str>, Option<&'static str>);
+    fn get_type_and_data(&self) -> (Option<&'a str>, Option<&'a str>);
 
     /// Returns true if this node has object data that is correct uri.
     fn has_object_data(&self) -> bool;
@@ -1088,8 +1088,8 @@ trait ObjectElement {
     fn get_object_data(&self) -> Option<Url>;
 }
 
-impl<'ln> ObjectElement for ThreadSafeLayoutNode<'ln> {
-    fn get_type_and_data(&self) -> (Option<&'static str>, Option<&'static str>) {
+impl<'ln> ObjectElement<'ln> for ThreadSafeLayoutNode<'ln> {
+    fn get_type_and_data(&self) -> (Option<&'ln str>, Option<&'ln str>) {
         let elem = self.as_element();
         (elem.get_attr(&namespace::Null, "type"), elem.get_attr(&namespace::Null, "data"))
     }

components/layout/wrapper.rs

@@ -401,11 +401,11 @@ impl<'le> TElement<'le> for LayoutElement<'le> {
     }
 
     #[inline]
-    fn get_attr(&self, namespace: &Namespace, name: &str) -> Option<&'static str> {
+    fn get_attr(&self, namespace: &Namespace, name: &str) -> Option<&'le str> {
         unsafe { self.element.get_attr_val_for_layout(namespace, name) }
     }
 
-    fn get_link(&self) -> Option<&'static str> {
+    fn get_link(&self) -> Option<&'le str> {
         // FIXME: This is HTML only.
         match self.element.node.type_id_for_layout() {
             // http://www.whatwg.org/specs/web-apps/current-work/multipage/selectors.html#
@@ -791,7 +791,7 @@ pub struct ThreadSafeLayoutElement<'le> {
 
 impl<'le> ThreadSafeLayoutElement<'le> {
     #[inline]
-    pub fn get_attr(&self, namespace: &Namespace, name: &str) -> Option<&'static str> {
+    pub fn get_attr(&self, namespace: &Namespace, name: &str) -> Option<&'le str> {
         unsafe { self.element.get_attr_val_for_layout(namespace, name) }
     }
 }

components/script/dom/element.rs

@@ -170,7 +170,7 @@ impl Element {
 }
 
 pub trait RawLayoutElementHelpers {
-    unsafe fn get_attr_val_for_layout(&self, namespace: &Namespace, name: &str) -> Option<&'static str>;
+    unsafe fn get_attr_val_for_layout<'a>(&'a self, namespace: &Namespace, name: &str) -> Option<&'a str>;
     unsafe fn get_attr_atom_for_layout(&self, namespace: &Namespace, name: &str) -> Option<Atom>;
     unsafe fn has_class_for_layout(&self, name: &str) -> bool;
 }
@@ -178,8 +178,8 @@ pub trait RawLayoutElementHelpers {
 impl RawLayoutElementHelpers for Element {
     #[inline]
     #[allow(unrooted_must_root)]
-    unsafe fn get_attr_val_for_layout(&self, namespace: &Namespace, name: &str)
-                                      -> Option<&'static str> {
+    unsafe fn get_attr_val_for_layout<'a>(&'a self, namespace: &Namespace, name: &str)
+                                          -> Option<&'a str> {
         // cast to point to T in RefCell<T> directly
         let attrs: *const Vec<JS<Attr>> = mem::transmute(&self.attrs);
         (*attrs).iter().find(|attr: & &JS<Attr>| {
@@ -949,12 +949,12 @@ impl<'a> VirtualMethods for JSRef<'a, Element> {
 }
 
 impl<'a> style::TElement<'a> for JSRef<'a, Element> {
-    fn get_attr(&self, namespace: &Namespace, attr: &str) -> Option<&'static str> {
+    fn get_attr(&self, namespace: &Namespace, attr: &str) -> Option<&'a str> {
         self.get_attribute(namespace.clone(), attr).root().map(|attr| {
             unsafe { mem::transmute(attr.deref().value().as_slice()) }
         })
     }
-    fn get_link(&self) -> Option<&'static str> {
+    fn get_link(&self) -> Option<&'a str> {
         // FIXME: This is HTML only.
         let node: JSRef<Node> = NodeCast::from_ref(*self);
         match node.type_id() {
@@ -966,10 +966,10 @@ impl<'a> style::TElement<'a> for JSRef<'a, Element> {
             _ => None,
          }
     }
-    fn get_local_name<'a>(&'a self) -> &'a Atom {
+    fn get_local_name<'b>(&'b self) -> &'b Atom {
         (self as &ElementHelpers).get_local_name()
     }
-    fn get_namespace<'a>(&'a self) -> &'a Namespace {
+    fn get_namespace<'b>(&'b self) -> &'b Namespace {
         (self as &ElementHelpers).get_namespace()
     }
     fn get_hover_state(&self) -> bool {

components/style/node.rs

@@ -24,10 +24,10 @@ pub trait TNode<'a, E: TElement<'a>> : Clone {
 }
 
 pub trait TElement<'a> {
-    fn get_attr(&self, namespace: &Namespace, attr: &str) -> Option<&'static str>;
-    fn get_link(&self) -> Option<&'static str>;
-    fn get_local_name<'a>(&'a self) -> &'a Atom;
-    fn get_namespace<'a>(&'a self) -> &'a Namespace;
+    fn get_attr(&self, namespace: &Namespace, attr: &str) -> Option<&'a str>;
+    fn get_link(&self) -> Option<&'a str>;
+    fn get_local_name<'b>(&'b self) -> &'b Atom;
+    fn get_namespace<'b>(&'b self) -> &'b Namespace;
     fn get_hover_state(&self) -> bool;
     fn get_id(&self) -> Option<Atom>;
     fn get_disabled_state(&self) -> bool;