Merge pull request #3088 from brunoabinader/document-links-cache

Implement Document.links cache; r=Ms2ger

2 files changed, 52 insertions, 22 deletions

diff --git a/src/components/script/dom/document.rs b/src/components/script/dom/document.rs
index eb9eb3d3929..69d8abaf75f 100644
--- a/src/components/script/dom/document.rs
+++ b/src/components/script/dom/document.rs
@@ -78,6 +78,7 @@ pub struct Document {
     pub is_html_document: bool,
     url: Untraceable<Url>,
     quirks_mode: Untraceable<Cell<QuirksMode>>,
+    links: Cell<Option<JS<HTMLCollection>>>,
 }
 
 impl DocumentDerived for EventTarget {
@@ -86,6 +87,13 @@ impl DocumentDerived for EventTarget {
     }
 }
 
+struct LinksFilter;
+impl CollectionFilter for LinksFilter {
+    fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
+        (elem.is_htmlanchorelement() || elem.is_htmlareaelement()) && elem.has_attribute("href")
+    }
+}
+
 pub trait DocumentHelpers {
     fn url<'a>(&'a self) -> &'a Url;
     fn quirks_mode(&self) -> QuirksMode;
@@ -228,6 +236,7 @@ impl Document {
             // http://dom.spec.whatwg.org/#concept-document-encoding
             encoding_name: Traceable::new(RefCell::new("utf-8".to_string())),
             is_html_document: is_html_document == HTMLDocument,
+            links: Cell::new(None),
         }
     }
 
@@ -657,8 +666,6 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
 
     fn Images(&self) -> Temporary<HTMLCollection> {
         let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         struct ImagesFilter;
         impl CollectionFilter for ImagesFilter {
             fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
@@ -671,8 +678,6 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
 
     fn Embeds(&self) -> Temporary<HTMLCollection> {
         let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         struct EmbedsFilter;
         impl CollectionFilter for EmbedsFilter {
             fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
@@ -684,29 +689,21 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
     }
 
     fn Plugins(&self) -> Temporary<HTMLCollection> {
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         self.Embeds()
     }
 
     fn Links(&self) -> Temporary<HTMLCollection> {
-        let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
-        struct LinksFilter;
-        impl CollectionFilter for LinksFilter {
-            fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
-                (elem.is_htmlanchorelement() || elem.is_htmlareaelement()) &&
-                    elem.get_attribute(Null, "href").is_some()
-            }
+        if self.links.get().is_none() {
+            let window = self.window.root();
+            let root = NodeCast::from_ref(self);
+            let filter = box LinksFilter;
+            self.links.assign(Some(HTMLCollection::create(&*window, root, filter)));
         }
-        let filter = box LinksFilter;
-        HTMLCollection::create(&*window, NodeCast::from_ref(self), filter)
+        Temporary::new(self.links.get().get_ref().clone())
     }
 
     fn Forms(&self) -> Temporary<HTMLCollection> {
         let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         struct FormsFilter;
         impl CollectionFilter for FormsFilter {
             fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
@@ -719,8 +716,6 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
 
     fn Scripts(&self) -> Temporary<HTMLCollection> {
         let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         struct ScriptsFilter;
         impl CollectionFilter for ScriptsFilter {
             fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
@@ -733,8 +728,6 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
 
     fn Anchors(&self) -> Temporary<HTMLCollection> {
         let window = self.window.root();
-
-        // FIXME: https://github.com/mozilla/servo/issues/1847
         struct AnchorsFilter;
         impl CollectionFilter for AnchorsFilter {
             fn filter(&self, elem: &JSRef<Element>, _root: &JSRef<Node>) -> bool {
diff --git a/src/test/content/test_document_links_cache.html b/src/test/content/test_document_links_cache.html
new file mode 100644
index 00000000000..ec6525510dc
--- /dev/null
+++ b/src/test/content/test_document_links_cache.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <script src="harness.js"></script>
+        <script>
+            var links = document.links;
+            is(links, document.links);
+            is(links.length, 0);
+
+            var anchor = document.createElement("a");
+            anchor.id = "anchor-with-href";
+            anchor.setAttribute("href", "http://www.google.com");
+            document.body.appendChild(anchor);
+            is(links.length, 1);
+
+            anchor = document.createElement("a");
+            anchor.id = "anchor-without-href";
+            document.body.appendChild(anchor);
+            is(links.length, 1);
+
+            anchor.setAttribute("href", "http://www.google.com");
+            is(links.length, 2);
+
+            anchor.removeAttribute("href", "http://www.google.com");
+            is(links.length, 1);
+
+            document.body.removeChild(document.getElementById("anchor-without-href"));
+            is(links.length, 1);
+
+            document.body.removeChild(document.getElementById("anchor-with-href"));
+            is(links, document.links);
+            is(links.length, 0);
+
+            finish();
+        </script>
+    </head>
+</html>