--- upload.module.orig	2006-07-04 09:24:33.000000000 -0700
+++ upload.module	2006-11-15 15:21:33.000000000 -0800
@@ -150,7 +150,17 @@
     if (user_access('view uploaded files')) {
       $node = node_load($file->nid);
       if (node_access('view', $node)) {
-        $name = mime_header_encode($file->filename);
+        // Mime filename should be double quoted to handle filenames with spaces
+        if (preg_match('/[^\x20-\x7E]/', $file->filename)) { 
+          // CASE 1 : non-ascii --> needs encoding.
+          $name = mime_header_encode($file->filename);
+        } else if (preg_match('/[ \(\)\<\>\@\,\;\:\\\"\/\[\]\?\=]/', $file->filename)) {
+          // CASE 2 : n tokens, tspecials characters, SHOULD be 'quoted-string'.
+          $name = '"'.$file->filename.'"';
+        } else {
+          // CASE 3 : only ascii, one token, no tspecials.
+          $name = $file->filename;
+        }
         $type = mime_header_encode($file->filemime);
         // Serve images and text inline for the browser to display rather than download.
         $disposition = ereg('^(text/|image/)', $file->filemime) ? 'inline' : 'attachment';