From 17d100576923e00673b295b6bfacb0558eb0925b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Ko=C5=82odziejski?= <tkolodziejski@mozilla.com>
Date: Fri, 29 Aug 2014 11:14:00 +0200
Subject: [PATCH] Bug 429732 - speed up highlighting by optimizing
 _getEditableNode. r=ehsan

---
 toolkit/modules/Finder.jsm | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/toolkit/modules/Finder.jsm b/toolkit/modules/Finder.jsm
index 10b4b0f775b..3abbf62fa2e 100644
--- a/toolkit/modules/Finder.jsm
+++ b/toolkit/modules/Finder.jsm
@@ -613,19 +613,18 @@ Finder.prototype = {
   },
 
   /*
-   * For a given node, walk up it's parent chain, to try and find an
-   * editable node.
+   * For a given node returns its editable parent or null if there is none.
+   * It's enough to check if aNode is a text node and its parent's parent is
+   * instance of nsIDOMNSEditableElement.
    *
    * @param aNode the node we want to check
    * @returns the first node in the parent chain that is editable,
    *          null if there is no such node
    */
   _getEditableNode: function (aNode) {
-    while (aNode) {
-      if (aNode instanceof Ci.nsIDOMNSEditableElement)
-        return aNode.editor ? aNode : null;
-
-      aNode = aNode.parentNode;
+    if (aNode.nodeType === aNode.TEXT_NODE && aNode.parentNode && aNode.parentNode.parentNode &&
+        aNode.parentNode.parentNode instanceof Ci.nsIDOMNSEditableElement) {
+      return aNode.parentNode.parentNode;
     }
     return null;
   },