Implement Element.matches().

src/components/script/dom/node.rs

@@ -396,6 +396,7 @@ pub trait NodeHelpers {
     fn query_selector_all(&self, selectors: DOMString) -> Fallible<Temporary<NodeList>>;
 
     fn remove_self(&self);
+    fn matches(&self, selectors: DOMString) -> Fallible<bool>;
 }
 
 impl<'a> NodeHelpers for JSRef<'a, Node> {
@@ -648,6 +649,28 @@ impl<'a> NodeHelpers for JSRef<'a, Node> {
             None => ()
         }
     }
+
+    // http://dom.spec.whatwg.org/#dom-element-matches
+    fn matches(&self, selectors: DOMString) -> Fallible<bool> {
+        assert!(self.is_element());
+        // Step 1.
+        let namespace = NamespaceMap::new();
+        match parse_selector_list(tokenize(selectors.as_slice()).map(|(token, _)| token).collect(), &namespace) {
+            // Step 2.
+            None => return Err(Syntax),
+            // Step 3.
+            Some(ref selectors) => {
+                for selector in selectors.iter() {
+                    assert!(selector.pseudo_element.is_none());
+                    let mut _shareable: bool = false;
+                    if matches_compound_selector(selector.compound_selectors.deref(), self, &mut _shareable) {
+                        return Ok(true);
+                    }
+                }
+            }
+        }
+        Ok(false)
+    }
 }
 
 /// If the given untrusted node address represents a valid DOM node in the given runtime,