| cache_set | includes/cache.inc | Store data in the persistent cache. |
| drupal_get_headers | includes/common.inc | Get the HTTP response headers for the current page. |
| page_get_cache | includes/bootstrap.inc | Retrieve the current page from the cache. |
| page_set_cache | includes/common.inc | Store the current page in the cache. |
| request_uri | includes/bootstrap.inc | Since $_SERVER['REQUEST_URI'] is only available on Apache, we
generate an equivalent using other environment variables. |
| variable_get | includes/bootstrap.inc | Return a persistent variable. |