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

components/layout/wrapper.rs

@@ -417,6 +417,12 @@ impl<'le> TElement for LayoutElement<'le> {
             self.element.node.get_enabled_state_for_layout()
         }
     }
+
+    fn has_class(&self, name: &str) -> bool {
+        unsafe {
+            self.element.has_class_for_layout(name)
+        }
+    }
 }
 
 fn get_content(content_list: &content::T) -> String {

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()
     }

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)
+    }
 }

components/style/node.rs

@@ -30,5 +30,6 @@ pub trait TElement {
     fn get_id(&self) -> Option<Atom>;
     fn get_disabled_state(&self) -> bool;
     fn get_enabled_state(&self) -> bool;
+    fn has_class(&self, name: &str) -> bool;
 }
 

components/style/selector_matching.rs

@@ -626,11 +626,7 @@ fn matches_simple_selector<E:TElement,
         // TODO: cache and intern class names on elements.
         ClassSelector(ref class) => {
             let element = element.as_element();
-            element.get_attr(&namespace::Null, "class")
+            element.has_class(class.as_slice())
-                    .map_or(false, |attr| {
-                // TODO: case-sensitivity depends on the document type and quirks mode
-                attr.split(SELECTOR_WHITESPACE).any(|c| c == class.as_slice())
-            })
         }
 
         AttrExists(ref attr) => {

tests/ref/basic.list

@@ -113,3 +113,6 @@ flaky_gpu,flaky_linux == acid2_noscroll.html acid2_ref_broken.html
 == abs_float_pref_width_a.html abs_float_pref_width_ref.html
 == alpha_png_a.html alpha_png_b.html
 == background_image_position_a.html background_image_position_ref.html
+
+# The following tests fails the ref-tests
+#== multiple_css_class_a.html multiple_css_class_b.html

tests/ref/multiple_css_class_a.html

@@ -0,0 +1,19 @@
+<html>
+  <head>
+    <style>
+    .foo {
+      height: 100px;
+    }
+    .bar {
+      width: 100px;
+    }
+    .baz {
+      background: green;
+    }
+    </style>
+  </head>
+  <body>
+    <div class="foo bar baz foobar">
+    </div>
+  </body>
+</html>

tests/ref/multiple_css_class_b.html

@@ -0,0 +1,15 @@
+<html>
+  <head>
+    <style>
+    .bar {
+      height: 100px;
+      width: 100px;
+      background: green;
+    }
+    </style>
+  </head>
+  <body>
+    <div class="foo bar baz foobar">
+    </div>
+  </body>
+</html>