function system_menu_tree_prune_tree

Prune a tree so that it begins at the specified level.

This function will follow the active menu trail to the specified level.

Parameters

array $tree: The menu tree to prune.

int $level: The level of the original tree that will start the pruned tree.

array $parent_item: The menu item that should be used as the root of the tree.

File

core/modules/system/system.menu.inc, line 370

Menu block configuration form and display.

Code

function system_menu_tree_prune_tree(array &$tree, $level, array $parent_item = NULL) {
  if (!empty($parent_item)) {
    // Prune the tree along the path to the menu item.
    for ($i = 1; $i <= MENU_MAX_DEPTH && $parent_item["p$i"] != '0'; $i++) {
      $plid = $parent_item["p$i"];
      $found_active_trail = FALSE;
      // Examine each element at this level for the ancestor.
      foreach ($tree as $key => &$value) {
        if ($tree[$key]['link']['mlid'] == $plid) {
          system_menu_block_set_title($tree[$key]['link']);
          // Prune the tree to the children of this ancestor.
          $tree = $tree[$key]['below'] ? $tree[$key]['below'] : array();
          $found_active_trail = TRUE;
          break;
        }
      }
      // If we don't find the ancestor, bail out.
      if (!$found_active_trail) {
        $tree = array();
        break;
      }
    }
  }

  $is_front_page = backdrop_is_front_page();
  // Trim the upper levels down to the one desired.
  for ($i = 1; $i < $level; $i++) {
    $found_active_trail = FALSE;
    // Examine each element at this level for the active trail.
    foreach ($tree as $key => &$value) {
      // Also include the children of the home page.
      if ($tree[$key]['link']['in_active_trail'] || ($tree[$key]['link']['link_path'] == '<front>' && $is_front_page)) {
        // Get the title for the pruned tree.
        system_menu_block_set_title($tree[$key]['link']);
        // Prune the tree to the children of the item in the active trail.
        $tree = $tree[$key]['below'] ? $tree[$key]['below'] : array();
        $found_active_trail = TRUE;
        break;
      }
    }
    // If we don't find the active trail, the active item isn't in the tree we want.
    if (!$found_active_trail) {
      $tree = array();
      break;
    }
  }
}