function _menu_tree_data

Builds the data representing a menu tree.

The function is a bit complex because the rendering of a link depends on the next menu link.

Related topics

File

drupal/core/includes/menu.inc, line 1574

API for the Drupal menu system.

Code

function _menu_tree_data(&$links, $parents, $depth) {
  $tree = array();
  while ($item = array_pop($links)) {

    // We need to determine if we're on the path to root so we can later build
    // the correct active trail and breadcrumb.
    $item['in_active_trail'] = in_array($item['mlid'], $parents);

    // Add the current link to the tree.
    $tree[$item['mlid']] = array(
      'link' => $item,
      'below' => array(),
    );

    // Look ahead to the next link, but leave it on the array so it's available
    // to other recursive function calls if we return or build a sub-tree.
    $next = end($links);

    // Check whether the next link is the first in a new sub-tree.
    if ($next && $next['depth'] > $depth) {

      // Recursively call _menu_tree_data to build the sub-tree.
      $tree[$item['mlid']]['below'] = _menu_tree_data($links, $parents, $next['depth']);

      // Fetch next link after filling the sub-tree.
      $next = end($links);
    }

    // Determine if we should exit the loop and return.
    if (!$next || $next['depth'] < $depth) {
      break;
    }
  }
  return $tree;
}