Factor out part of the traversal routine in HTMLCollection.

I would move the filter() call into the traverse function as well, but the
callback can't outlive its stack frame.

1 files changed, 19 insertions, 24 deletions

diff --git a/components/script/dom/htmlcollection.rs b/components/script/dom/htmlcollection.rs
index 91034fd4423..8a95b558793 100644
--- a/components/script/dom/htmlcollection.rs
+++ b/components/script/dom/htmlcollection.rs
@@ -10,12 +10,13 @@ use dom::bindings::js::{JS, JSRef, Temporary};
 use dom::bindings::trace::JSTraceable;
 use dom::bindings::utils::{Reflectable, Reflector, reflect_dom_object};
 use dom::element::{Element, AttributeHandlers, ElementHelpers};
-use dom::node::{Node, NodeHelpers};
+use dom::node::{Node, NodeHelpers, TreeIterator};
 use dom::window::Window;
 use servo_util::namespace;
 use servo_util::str::{DOMString, split_html_space_chars};
 
 use std::ascii::AsciiExt;
+use std::iter::FilterMap;
 use string_cache::{Atom, Namespace};
 
 pub trait CollectionFilter : JSTraceable {
@@ -171,6 +172,14 @@ impl HTMLCollection {
         }
         HTMLCollection::create(window, root, box ElementChildFilter)
     }
+
+    fn traverse<'a>(root: JSRef<'a, Node>)
+                    -> FilterMap<'a, JSRef<'a, Node>,
+                                 JSRef<'a, Element>,
+                                 TreeIterator<'a>> {
+        root.traverse_preorder()
+            .filter_map(ElementCast::to_ref)
+    }
 }
 
 impl<'a> HTMLCollectionMethods for JSRef<'a, HTMLCollection> {
@@ -180,11 +189,9 @@ impl<'a> HTMLCollectionMethods for JSRef<'a, HTMLCollection> {
             Static(ref elems) => elems.len() as u32,
             Live(ref root, ref filter) => {
                 let root = root.root();
-                root.traverse_preorder()
-                    .filter(|&child| {
-                        let elem: Option<JSRef<Element>> = ElementCast::to_ref(child);
-                        elem.map_or(false, |elem| filter.filter(elem, *root))
-                    }).count() as u32
+                HTMLCollection::traverse(*root)
+                    .filter(|element| filter.filter(*element, *root))
+                    .count() as u32
             }
         }
     }
@@ -198,17 +205,11 @@ impl<'a> HTMLCollectionMethods for JSRef<'a, HTMLCollection> {
                 .map(|elem| Temporary::new(elem.clone())),
             Live(ref root, ref filter) => {
                 let root = root.root();
-                root.traverse_preorder()
-                    .filter_map(|node| {
-                        let elem: Option<JSRef<Element>> = ElementCast::to_ref(node);
-                        match elem {
-                            Some(ref elem) if filter.filter(*elem, *root) => Some(elem.clone()),
-                            _ => None
-                        }
-                    })
+                HTMLCollection::traverse(*root)
+                    .filter(|element| filter.filter(*element, *root))
                     .nth(index as uint)
                     .clone()
-                    .map(|elem| Temporary::from_rooted(elem))
+                    .map(Temporary::from_rooted)
             }
         }
     }
@@ -230,18 +231,12 @@ impl<'a> HTMLCollectionMethods for JSRef<'a, HTMLCollection> {
                 .map(|maybe_elem| Temporary::from_rooted(*maybe_elem)),
             Live(ref root, ref filter) => {
                 let root = root.root();
-                root.traverse_preorder()
-                    .filter_map(|node| {
-                        let elem: Option<JSRef<Element>> = ElementCast::to_ref(node);
-                        match elem {
-                            Some(ref elem) if filter.filter(*elem, *root) => Some(elem.clone()),
-                            _ => None
-                        }
-                    })
+                HTMLCollection::traverse(*root)
+                    .filter(|element| filter.filter(*element, *root))
                     .find(|elem| {
                         elem.get_string_attribute(&atom!("name")) == key ||
                         elem.get_string_attribute(&atom!("id")) == key })
-                    .map(|maybe_elem| Temporary::from_rooted(maybe_elem))
+                    .map(Temporary::from_rooted)
             }
         }
     }