function taxonomy_get_tree

Create a hierarchical representation of a vocabulary.

Parameters

$vid: Which vocabulary to generate the tree for.

$parent: The term ID under which to generate the tree. If 0, generate the tree for the entire vocabulary.

$depth: Internal use only.

$max_depth: The number of levels of the tree to return. Leave NULL to return all levels.

Return value

An array of all term objects in the tree. Each term object is extended to have "depth" and "parents" attributes in addition to its normal ones. Results are statically cached.

File

modules/taxonomy/taxonomy.module, line 988

Enables the organization of content into categories.

Code

function taxonomy_get_tree($vid, $parent = 0, $depth = -1, $max_depth = NULL) {
  static $children, $parents, $terms;
  $depth++;

  // We cache trees, so it's not CPU-intensive to call get_tree() on a term
  // and its children, too.
  if (!isset($children[$vid])) {
    $children[$vid] = array();
    $result = db_query(db_rewrite_sql('SELECT t.tid, t.*, parent FROM {term_data} t INNER JOIN  {term_hierarchy} h ON t.tid = h.tid WHERE t.vid = %d ORDER BY weight, name', 't', 'tid'), $vid);
    while ($term = db_fetch_object($result)) {
      $children[$vid][$term->parent][] = $term->tid;
      $parents[$vid][$term->tid][] = $term->parent;
      $terms[$vid][$term->tid] = $term;
    }
  }
  $max_depth = is_null($max_depth) ? count($children[$vid]) : $max_depth;
  if ($children[$vid][$parent]) {
    foreach ($children[$vid][$parent] as $child) {
      if ($max_depth > $depth) {
        $term = drupal_clone($terms[$vid][$child]);
        $term->depth = $depth;

        // The "parent" attribute is not useful, as it would show one parent only.
        unset($term->parent);
        $term->parents = $parents[$vid][$child];
        $tree[] = $term;
        if ($children[$vid][$child]) {
          $tree = array_merge($tree, taxonomy_get_tree($vid, $child, $depth, $max_depth));
        }
      }
    }
  }
  return $tree ? $tree : array();
}