auto merge of #4219 : Ms2ger/servo/cleanup-document, r=jdm

1 files changed, 21 insertions, 25 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index c3c71cb5101..726e7e69516 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -520,18 +520,16 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
     // http://dom.spec.whatwg.org/#dom-document-doctype
     fn GetDoctype(self) -> Option<Temporary<DocumentType>> {
         let node: JSRef<Node> = NodeCast::from_ref(self);
-        node.children().find(|child| {
-            child.is_doctype()
-        }).map(|node| {
-            let doctype: JSRef<DocumentType> = DocumentTypeCast::to_ref(node).unwrap();
-            Temporary::from_rooted(doctype)
-        })
+        node.children()
+            .filter_map(DocumentTypeCast::to_ref)
+            .next()
+            .map(Temporary::from_rooted)
     }
 
     // http://dom.spec.whatwg.org/#dom-document-documentelement
     fn GetDocumentElement(self) -> Option<Temporary<Element>> {
         let node: JSRef<Node> = NodeCast::from_ref(self);
-        node.child_elements().next().map(|elem| Temporary::from_rooted(elem))
+        node.child_elements().next().map(Temporary::from_rooted)
     }
 
     // http://dom.spec.whatwg.org/#dom-document-getelementsbytagname
@@ -823,21 +821,21 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
     // http://www.whatwg.org/specs/web-apps/current-work/#dom-document-body
     fn SetBody(self, new_body: Option<JSRef<HTMLElement>>) -> ErrorResult {
         // Step 1.
-        match new_body {
-            Some(ref htmlelem) => {
-                let node: JSRef<Node> = NodeCast::from_ref(*htmlelem);
-                match node.type_id() {
-                    ElementNodeTypeId(HTMLBodyElementTypeId) | ElementNodeTypeId(HTMLFrameSetElementTypeId) => {}
-                    _ => return Err(HierarchyRequest)
-                }
-            }
-            None => return Err(HierarchyRequest)
+        let new_body = match new_body {
+            Some(new_body) => new_body,
+            None => return Err(HierarchyRequest),
+        };
+
+        let node: JSRef<Node> = NodeCast::from_ref(new_body);
+        match node.type_id() {
+            ElementNodeTypeId(HTMLBodyElementTypeId) |
+            ElementNodeTypeId(HTMLFrameSetElementTypeId) => {}
+            _ => return Err(HierarchyRequest)
         }
 
         // Step 2.
         let old_body = self.GetBody().root();
-        //FIXME: covariant lifetime workaround. do not judge.
-        if old_body.as_ref().map(|body| body.deref()) == new_body.as_ref().map(|a| &*a) {
+        if old_body.as_ref().map(|body| **body) == Some(new_body) {
             return Ok(());
         }
 
@@ -846,8 +844,7 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
             // Step 4.
             None => return Err(HierarchyRequest),
             Some(ref root) => {
-                let new_body_unwrapped = new_body.unwrap();
-                let new_body: JSRef<Node> = NodeCast::from_ref(new_body_unwrapped);
+                let new_body: JSRef<Node> = NodeCast::from_ref(new_body);
 
                 let root: JSRef<Node> = NodeCast::from_ref(**root);
                 match old_body {
@@ -866,11 +863,10 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
     // http://www.whatwg.org/specs/web-apps/current-work/#dom-document-getelementsbyname
     fn GetElementsByName(self, name: DOMString) -> Temporary<NodeList> {
         self.createNodeList(|node| {
-            if !node.is_element() {
-                return false;
-            }
-
-            let element: JSRef<Element> = ElementCast::to_ref(node).unwrap();
+            let element: JSRef<Element> = match ElementCast::to_ref(node) {
+                Some(element) => element,
+                None => return false,
+            };
             element.get_attribute(ns!(""), &atom!("name")).root().map_or(false, |attr| {
                 attr.value().as_slice() == name.as_slice()
             })