Make use of the list of Atoms in ClassSelector

Make use of the list of Atoms in the class attribute selector
(ClassSelector) in selector_matching.

Fixes #3111

2 files changed, 26 insertions, 0 deletions

diff --git a/components/script/dom/attr.rs b/components/script/dom/attr.rs
index 02945088bbb..4da59b96b55 100644
--- a/components/script/dom/attr.rs
+++ b/components/script/dom/attr.rs
@@ -188,6 +188,7 @@ impl<'a> AttrHelpers for JSRef<'a, Attr> {
 pub trait AttrHelpersForLayout {
     unsafe fn value_ref_forever(&self) -> &'static str;
     unsafe fn value_atom_forever(&self) -> Option<Atom>;
+    unsafe fn value_tokens_forever(&self) -> Option<Items<Atom>>;
     unsafe fn local_name_atom_forever(&self) -> Atom;
 }
 
@@ -207,6 +208,15 @@ impl AttrHelpersForLayout for Attr {
         }
     }
 
+    unsafe fn value_tokens_forever(&self) -> Option<Items<Atom>> {
+        // cast to point to T in RefCell<T> directly
+        let value = mem::transmute::<&RefCell<AttrValue>, &AttrValue>(self.value.deref());
+        match *value {
+            TokenListAttrValue(_, ref tokens) => Some(tokens.iter()),
+            _ => None,
+        }
+    }
+
     unsafe fn local_name_atom_forever(&self) -> Atom {
         self.local_name.clone()
     }
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index a4df58eb06e..30b2601f04e 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -168,6 +168,7 @@ impl Element {
 pub trait RawLayoutElementHelpers {
     unsafe fn get_attr_val_for_layout(&self, namespace: &Namespace, name: &str) -> Option<&'static str>;
     unsafe fn get_attr_atom_for_layout(&self, namespace: &Namespace, name: &str) -> Option<Atom>;
+    unsafe fn has_class_for_layout(&self, name: &str) -> bool;
 }
 
 impl RawLayoutElementHelpers for Element {
@@ -200,6 +201,18 @@ impl RawLayoutElementHelpers for Element {
             (*attr).value_atom_forever()
         })
     }
+
+    #[inline]
+    unsafe fn has_class_for_layout(&self, name: &str) -> bool {
+        let attrs: *const Vec<JS<Attr>> = mem::transmute(&self.attrs);
+        (*attrs).iter().find(|attr: & &JS<Attr>| {
+            let attr = attr.unsafe_get();
+            (*attr).local_name_atom_forever().as_slice() == "class"
+        }).map_or(false, |attr| {
+            let attr = attr.unsafe_get();
+            (*attr).value_tokens_forever().map(|mut tokens| { tokens.any(|atom| atom.as_slice() == name) })
+        }.take().unwrap())
+    }
 }
 
 pub trait LayoutElementHelpers {
@@ -955,4 +968,7 @@ impl<'a> style::TElement for JSRef<'a, Element> {
         let node: &JSRef<Node> = NodeCast::from_ref(self);
         node.get_enabled_state()
     }
+    fn has_class(&self, name: &str) -> bool {
+        (self as &AttributeHandlers).has_class(name)
+    }
 }