From 0fcaa3ce0393b713e38850ee8c83c3e105015daa Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Fri, 27 Mar 2015 19:00:50 -0700
Subject: [PATCH] script: Fix O(n^2) dirty bit marking when setting style on
 all immediate children of a node.

---
 components/script/dom/node.rs | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 67bb5279f32..ae79327e7da 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -700,14 +700,16 @@ impl<'a> NodeHelpers<'a> for JSRef<'a, Node> {
         //
         // TODO(cgaebel): This is a very conservative way to account for sibling
         // selectors. Maybe we can do something smarter in the future.
-        let parent =
-            match self.parent_node() {
-                None         => return,
-                Some(parent) => parent,
-            };
+        if !self.get_has_dirty_siblings() {
+            let parent =
+                match self.parent_node() {
+                    None         => return,
+                    Some(parent) => parent,
+                };
 
-        for sibling in parent.root().r().children() {
-            sibling.set_has_dirty_siblings(true);
+            for sibling in parent.root().r().children() {
+                sibling.set_has_dirty_siblings(true);
+            }
         }
 
         // 4. Dirty ancestors.