function TermStorage::loadTree

Overrides TermStorageInterface::loadTree

File

core/modules/taxonomy/src/TermStorage.php, line 220

Class

TermStorage

Defines a Controller class for taxonomy terms.

Namespace

Code

public function loadTree($vid, $parent = 0, $max_depth = NULL, $load_entities = FALSE) {
    $cache_key = implode(':', func_get_args());
    if (!isset($this->trees[$cache_key])) {
        // We cache trees, so it's not CPU-intensive to call on a term and its
        // children, too.
        if (!isset($this->treeChildren[$vid])) {
            $this->treeChildren[$vid] = [];
            $this->treeParents[$vid] = [];
            $this->treeTerms[$vid] = [];
            $query = $this->database
                ->select($this->getDataTable(), 't');
            $query->join('taxonomy_term__parent', 'p', 't.tid = p.entity_id');
            $query->addExpression('parent_target_id', 'parent');
            $result = $query->addTag('taxonomy_term_access')
                ->fields('t')
                ->condition('t.vid', $vid)
                ->condition('t.default_langcode', 1)
                ->orderBy('t.weight')
                ->orderBy('t.name')
                ->execute();
            foreach ($result as $term) {
                $this->treeChildren[$vid][$term->parent][] = $term->tid;
                $this->treeParents[$vid][$term->tid][] = $term->parent;
                $this->treeTerms[$vid][$term->tid] = $term;
            }
        }
        // Load full entities, if necessary. The entity controller statically
        // caches the results.
        $term_entities = [];
        if ($load_entities) {
            $term_entities = $this->loadMultiple(array_keys($this->treeTerms[$vid]));
        }
        $max_depth = !isset($max_depth) ? count($this->treeChildren[$vid]) : $max_depth;
        $tree = [];
        // Keeps track of the parents we have to process, the last entry is used
        // for the next processing step.
        $process_parents = [];
        $process_parents[] = $parent;
        // Loops over the parent terms and adds its children to the tree array.
        // Uses a loop instead of a recursion, because it's more efficient.
        while (count($process_parents)) {
            $parent = array_pop($process_parents);
            // The number of parents determines the current depth.
            $depth = count($process_parents);
            if ($max_depth > $depth && !empty($this->treeChildren[$vid][$parent])) {
                $has_children = FALSE;
                $child = current($this->treeChildren[$vid][$parent]);
                do {
                    if (empty($child)) {
                        break;
                    }
                    $term = $load_entities ? $term_entities[$child] : $this->treeTerms[$vid][$child];
                    if (isset($this->treeParents[$vid][$load_entities ? $term->id() : $term->tid])) {
                        // Clone the term so that the depth attribute remains correct
                        // in the event of multiple parents.
                        $term = clone $term;
                    }
                    $term->depth = $depth;
                    if (!$load_entities) {
                        unset($term->parent);
                    }
                    $tid = $load_entities ? $term->id() : $term->tid;
                    $term->parents = $this->treeParents[$vid][$tid];
                    $tree[] = $term;
                    if (!empty($this->treeChildren[$vid][$tid])) {
                        $has_children = TRUE;
                        // We have to continue with this parent later.
                        $process_parents[] = $parent;
                        // Use the current term as parent for the next iteration.
                        $process_parents[] = $tid;
                        // Reset pointers for child lists because we step in there more
                        // often with multi parents.
                        reset($this->treeChildren[$vid][$tid]);
                        // Move pointer so that we get the correct term the next time.
                        next($this->treeChildren[$vid][$parent]);
                        break;
                    }
                } while ($child = next($this->treeChildren[$vid][$parent]));
                if (!$has_children) {
                    // We processed all terms in this hierarchy-level, reset pointer
                    // so that this function works the next time it gets called.
                    reset($this->treeChildren[$vid][$parent]);
                }
            }
        }
        $this->trees[$cache_key] = $tree;
    }
    return $this->trees[$cache_key];
}