From 4b7e1c906f497784329622d82da08c8646cae7e6 Mon Sep 17 00:00:00 2001
From: John Resig <jeresig@gmail.com>
Date: Tue, 17 Feb 2009 17:43:05 +0000
Subject: [PATCH] Brought back the compareDocumentPosition code. While it is
 redundant in Firefox it's much faster than using indexOf.

---
 src/selector.js       | 12 ++++++++++--
 test/unit/selector.js |  4 ++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/selector.js b/src/selector.js
index c97ba61ff2..6538d9706d 100644
--- a/src/selector.js
+++ b/src/selector.js
@@ -684,7 +684,15 @@ try {
 
 var sortOrder;
 
-if ( Array.prototype.indexOf ) {
+if ( document.documentElement.compareDocumentPosition ) {
+	sortOrder = function( a, b ) {
+		var ret = a.compareDocumentPosition(b) & 4 ? -1 : a === b ? 0 : 1;
+		if ( ret === 0 ) {
+			hasDuplicate = true;
+		}
+		return ret;
+	};
+} else if ( Array.prototype.indexOf ) {
 	var indexOf = Array.prototype.indexOf,
 		allSort = document.getElementsByTagName("*");
 
@@ -695,7 +703,7 @@ if ( Array.prototype.indexOf ) {
 		}
 		return ret;
 	};
-} else if ( document.documentElement.sourceIndex === 1 ) {
+} else if ( "sourceIndex" in document.documentElement ) {
 	sortOrder = function( a, b ) {
 		var ret = a.sourceIndex - b.sourceIndex;
 		if ( ret === 0 ) {
diff --git a/test/unit/selector.js b/test/unit/selector.js
index a6b0458cdf..425ad8c831 100644
--- a/test/unit/selector.js
+++ b/test/unit/selector.js
@@ -1,7 +1,7 @@
 module("selector");
 
 test("element", function() {
-	expect(17);
+	expect(18);
 	reset();
 
 	ok( jQuery("*").size() >= 30, "Select all" );
@@ -25,7 +25,7 @@ test("element", function() {
 	ok( jQuery("#lengthtest input").length, '&lt;input name="length"&gt; cannot be found under IE, see #945' );
 
 	// Check for unique-ness and sort order
-	//isSet( jQuery("*"), jQuery("*, *"), "Check for duplicates: *, *" );
+	isSet( jQuery("*"), jQuery("*, *"), "Check for duplicates: *, *" );
 	isSet( jQuery("p"), jQuery("p, div p"), "Check for duplicates: p, div p" );
 
 	t( "Checking sort order", "h2, h1", ["header", "banner", "userAgent"] );