function BookManager::bookSubtreeData

Overrides BookManagerInterface::bookSubtreeData

File

core/modules/book/src/BookManager.php, line 1113

Class

BookManager

Defines a book manager.

Namespace

Code

public function bookSubtreeData($link) {
    $tree =& drupal_static(__METHOD__, []);
    // Generate a cache ID (cid) specific for this $link.
    $cid = 'book-links:subtree-cid:' . $link['nid'];
    if (!isset($tree[$cid])) {
        $tree_cid_cache = \Drupal::cache('data')->get($cid);
        if ($tree_cid_cache && $tree_cid_cache->data) {
            // If the cache entry exists, it will just be the cid for the actual
            // data. This avoids duplication of large amounts of data.
            $cache = \Drupal::cache('data')->get($tree_cid_cache->data);
            if ($cache && isset($cache->data)) {
                $data = $cache->data;
            }
        }
        // If the subtree data was not in the cache, $data will be NULL.
        if (!isset($data)) {
            $result = $this->bookOutlineStorage
                ->getBookSubtree($link, static::BOOK_MAX_DEPTH);
            $links = [];
            foreach ($result as $item) {
                $links[] = $item;
            }
            $data['tree'] = $this->buildBookOutlineData($links, [], $link['depth']);
            $data['node_links'] = [];
            $this->bookTreeCollectNodeLinks($data['tree'], $data['node_links']);
            // Compute the real cid for book subtree data.
            $tree_cid = 'book-links:subtree-data:' . hash('sha256', serialize($data));
            // Cache the data, if it is not already in the cache.
            if (!\Drupal::cache('data')->get($tree_cid)) {
                \Drupal::cache('data')->set($tree_cid, $data, Cache::PERMANENT, [
                    'bid:' . $link['bid'],
                ]);
            }
            // Cache the cid of the (shared) data using the book and item-specific
            // cid.
            \Drupal::cache('data')->set($cid, $tree_cid, Cache::PERMANENT, [
                'bid:' . $link['bid'],
            ]);
        }
        // Check access for the current user to each item in the tree.
        $this->bookTreeCheckAccess($data['tree'], $data['node_links']);
        $tree[$cid] = $data['tree'];
    }
    return $tree[$cid];
}