function menu_rebuild

Populates the database tables used by various menu functions.

This function will clear and populate the {menu_router} table, add entries to {menu_links} for new router items, and then remove stale items from {menu_links}. If called from update.php or install.php, it will also schedule a call to itself on the first real page load from menu_execute_active_handler(), because the maintenance page environment is different and leaves stale data in the menu tables.

Return value

TRUE if the menu was rebuilt, FALSE if another thread was rebuilding in parallel and the current thread just waited for completion.

Related topics

File

includes/menu.inc, line 2774

API for the Drupal menu system.

Code

function menu_rebuild() {
  if (!lock_acquire('menu_rebuild')) {

    // Wait for another request that is already doing this work.
    // We choose to block here since otherwise the router item may not
    // be available in menu_execute_active_handler() resulting in a 404.
    lock_wait('menu_rebuild');
    if (_menu_check_rebuild()) {

      // If we get here and menu_masks was not set, then it is possible a menu
      // is being reloaded, or that the process rebuilding the menu was unable
      // to complete successfully. A missing menu_masks variable could result
      // in a 404, so re-run the function.
      return menu_rebuild();
    }
    return FALSE;
  }
  $transaction = db_transaction();
  try {
    list($menu, $masks) = menu_router_build();
    _menu_router_save($menu, $masks);
    _menu_navigation_links_rebuild($menu);

    // Clear the menu, page and block caches.
    menu_cache_clear_all();
    _menu_clear_page_cache();
    if (defined('MAINTENANCE_MODE')) {
      variable_set('menu_rebuild_needed', TRUE);
    }
    else {
      variable_del('menu_rebuild_needed');
    }
  } catch (Exception $e) {
    $transaction
      ->rollback();
    watchdog_exception('menu', $e);
  }

  // Explicitly commit the transaction now; this ensures that the database
  // operations during the menu rebuild are committed before the lock is made
  // available again, since locks may not always reside in the same database
  // connection. The lock is acquired outside of the transaction so should also
  // be released outside of it.
  unset($transaction);
  lock_release('menu_rebuild');
  return TRUE;
}