Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.756.2.80
diff -u -9 -p -r1.756.2.80 common.inc
--- includes/common.inc	4 Mar 2010 00:25:13 -0000	1.756.2.80
+++ includes/common.inc	16 Apr 2010 11:09:06 -0000
@@ -1847,19 +1847,19 @@ function drupal_get_css($css = NULL) {
 
   $preprocess_css = (variable_get('preprocess_css', FALSE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update'));
   $directory = file_directory_path();
   $is_writable = is_dir($directory) && is_writable($directory) && (variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC) == FILE_DOWNLOADS_PUBLIC);
 
   // A dummy query-string is added to filenames, to gain control over
   // browser-caching. The string changes on every update or full cache
   // flush, forcing browsers to load a new copy of the files, as the
   // URL changed.
-  $query_string = '?'. substr(variable_get('css_js_query_string', '0'), 0, 1);
+  $query_string = '?'. variable_get('css_js_query_string', '0');
 
   foreach ($css as $media => $types) {
     // If CSS preprocessing is off, we still need to output the styles.
     // Additionally, go through any remaining styles if CSS preprocessing is on and output the non-cached ones.
     foreach ($types as $type => $files) {
       if ($type == 'module') {
         // Setup theme overrides for module styles.
         $theme_styles = array();
         foreach (array_keys($css[$media]['theme']) as $theme_style) {
@@ -2202,19 +2202,19 @@ function drupal_get_js($scope = 'header'
   $directory = file_directory_path();
   $is_writable = is_dir($directory) && is_writable($directory) && (variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC) == FILE_DOWNLOADS_PUBLIC);
 
   // A dummy query-string is added to filenames, to gain control over
   // browser-caching. The string changes on every update or full cache
   // flush, forcing browsers to load a new copy of the files, as the
   // URL changed. Files that should not be cached (see drupal_add_js())
   // get time() as query-string instead, to enforce reload on every
   // page request.
-  $query_string = '?'. substr(variable_get('css_js_query_string', '0'), 0, 1);
+  $query_string = '?'. variable_get('css_js_query_string', '0');
 
   // For inline Javascript to validate as XHTML, all Javascript containing
   // XHTML needs to be wrapped in CDATA. To make that backwards compatible
   // with HTML 4, we need to comment out the CDATA-tag.
   $embed_prefix = "\n<!--//--><![CDATA[//><!--\n";
   $embed_suffix = "\n//--><!]]>\n";
 
   foreach ($javascript as $type => $data) {
 
@@ -3710,25 +3710,16 @@ function drupal_flush_all_caches() {
   $cache_tables = array_merge(module_invoke_all('flush_caches'), $core);
   foreach ($cache_tables as $table) {
     cache_clear_all('*', $table, TRUE);
   }
 }
 
 /**
  * Helper function to change query-strings on css/js files.
  *
- * Changes the character added to all css/js files as dummy query-string,
- * so that all browsers are forced to reload fresh files. We keep
- * 20 characters history (FIFO) to avoid repeats, but only the first
- * (newest) character is actually used on urls, to keep them short.
- * This is also called from update.php.
+ * Changes the character added to all css/js files as dummy query-string, so
+ * that all browsers are forced to reload fresh files.
  */
 function _drupal_flush_css_js() {
-  $string_history = variable_get('css_js_query_string', '00000000000000000000');
-  $new_character = $string_history[0];
-  // Not including 'q' to allow certain JavaScripts to re-use query string.
-  $characters = 'abcdefghijklmnoprstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
-  while (strpos($string_history, $new_character) !== FALSE) {
-    $new_character = $characters[mt_rand(0, strlen($characters) - 1)];
-  }
-  variable_set('css_js_query_string', $new_character . substr($string_history, 0, 19));
+  // The timestamp is converted to base 36 in order to make it more compact.
+  variable_set('css_js_query_string', base_convert(time(), 10, 36));
 }