From 30af255fd7e13da0417e68a7d71232bdfbdb549e Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Wed, 24 Sep 2014 17:41:05 -0400
Subject: [PATCH] reduce overhead of mutation observer handler

---
 js/contentscript-end.js | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/js/contentscript-end.js b/js/contentscript-end.js
index 000f505c7..1fd0edde8 100644
--- a/js/contentscript-end.js
+++ b/js/contentscript-end.js
@@ -542,7 +542,7 @@ var uBlockMessaging = (function(name){
             iNode = nodeList.length;
             while ( iNode-- ) {
                 node = nodeList[iNode];
-                if ( typeof node.querySelectorAll !== 'function' ) {
+                if ( node.nodeType !== 1 ) {
                     continue;
                 }
                 if ( ignoreTags.hasOwnProperty(node.tagName) ) {
@@ -561,11 +561,12 @@ var uBlockMessaging = (function(name){
 
     // https://github.com/gorhill/uBlock/issues/205
     // Do not handle added node directly from within mutation observer.
-    var mutationObservedHandlerAsync = function(mutations) {
+    var treeMutationObservedHandlerAsync = function(mutations) {
         var iMutation = mutations.length;
         var nodeList;
         while ( iMutation-- ) {
-            if ( nodeList = mutations[iMutation].addedNodes ) {
+            nodeList = mutations[iMutation].addedNodes;
+            if ( nodeList.length !== 0 ) {
                 addedNodeLists.push(nodeList);
             }
         }
@@ -573,16 +574,14 @@ var uBlockMessaging = (function(name){
             // I arbitrarily chose 50 ms for now:
             // I have to compromise between the overhead of processing too few 
             // nodes too often and the delay of many nodes less often.
-            addedNodeListsTimer = setTimeout(mutationObservedHandler, 50);
+            addedNodeListsTimer = setTimeout(mutationObservedHandler, 75);
         }
     };
 
     // https://github.com/gorhill/httpswitchboard/issues/176
-    var observer = new MutationObserver(mutationObservedHandlerAsync);
-    observer.observe(document.body, {
-        attributes: false,
+    var treeObserver = new MutationObserver(treeMutationObservedHandlerAsync);
+    treeObserver.observe(document.body, {
         childList: true,
-        characterData: false,
         subtree: true
     });
 })();