From 316a5f9d2688f8017de9190ab0f93a33deb3efcd Mon Sep 17 00:00:00 2001
From: alec <alec@208e9e7b-5314-0410-a742-e7e81cd9613c>
Date: Fri, 4 Jun 2010 10:06:10 +0000
Subject: - performance improvement: we can skip THREAD when folder is empty

git-svn-id: https://svn.roundcube.net/trunk@3713 208e9e7b-5314-0410-a742-e7e81cd9613c
---
 roundcubemail/program/include/rcube_imap_generic.php | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/roundcubemail/program/include/rcube_imap_generic.php b/roundcubemail/program/include/rcube_imap_generic.php
index ab37902ae..411e1d396 100644
--- a/roundcubemail/program/include/rcube_imap_generic.php
+++ b/roundcubemail/program/include/rcube_imap_generic.php
@@ -1552,8 +1552,15 @@ class rcube_imap_generic
 
     function thread($folder, $algorithm='REFERENCES', $criteria='', $encoding='US-ASCII')
     {
+        $old_sel = $this->selected;
+
 	    if (!$this->select($folder)) {
-		    return false;
+    		return false;
+	    }
+
+        // return empty result when folder is empty and we're just after SELECT
+        if ($old_sel != $folder && !$this->exists) {
+            return array(array(), array(), array());
 	    }
 
     	$encoding  = $encoding ? trim($encoding) : 'US-ASCII';
-- 
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