function book_menu_subtree_data

Gets the data representing a subtree of the book hierarchy.

The root of the subtree will be the link passed as a parameter, so the returned tree will contain this item and all its descendents in the menu tree.

Parameters

$link: A fully loaded menu link.

Return value

A subtree of menu links in an array, in the order they should be rendered.

File

modules/book/book.module, line 1383

Code

function book_menu_subtree_data($link) {
    $tree =& drupal_static(__FUNCTION__, array());
    // Generate a cache ID (cid) specific for this $menu_name and $link.
    $cid = 'links:' . $link['menu_name'] . ':subtree-cid:' . $link['mlid'];
    if (!isset($tree[$cid])) {
        $cache = cache_get($cid, 'cache_menu');
        if ($cache && isset($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.
            $cache = cache_get($cache->data, 'cache_menu');
            if ($cache && isset($cache->data)) {
                $data = $cache->data;
            }
        }
        // If the subtree data was not in the cache, $data will be NULL.
        if (!isset($data)) {
            $query = db_select('menu_links', 'ml', array(
                'fetch' => PDO::FETCH_ASSOC,
            ));
            $query->join('menu_router', 'm', 'm.path = ml.router_path');
            $query->join('book', 'b', 'ml.mlid = b.mlid');
            $query->fields('b');
            $query->fields('m', array(
                'load_functions',
                'to_arg_functions',
                'access_callback',
                'access_arguments',
                'page_callback',
                'page_arguments',
                'delivery_callback',
                'title',
                'title_callback',
                'title_arguments',
                'type',
            ));
            $query->fields('ml');
            $query->condition('menu_name', $link['menu_name']);
            for ($i = 1; $i <= MENU_MAX_DEPTH && $link["p{$i}"]; ++$i) {
                $query->condition("p{$i}", $link["p{$i}"]);
            }
            for ($i = 1; $i <= MENU_MAX_DEPTH; ++$i) {
                $query->orderBy("p{$i}");
            }
            $links = array();
            foreach ($query->execute() as $item) {
                $links[] = $item;
            }
            $data['tree'] = menu_tree_data($links, array(), $link['depth']);
            $data['node_links'] = array();
            menu_tree_collect_node_links($data['tree'], $data['node_links']);
            // Compute the real cid for book subtree data.
            $tree_cid = 'links:' . $item['menu_name'] . ':subtree-data:' . hash('sha256', serialize($data));
            // Cache the data, if it is not already in the cache.
            if (!cache_get($tree_cid, 'cache_menu')) {
                cache_set($tree_cid, $data, 'cache_menu');
            }
            // Cache the cid of the (shared) data using the menu and item-specific cid.
            cache_set($cid, $tree_cid, 'cache_menu');
        }
        // Check access for the current user to each item in the tree.
        menu_tree_check_access($data['tree'], $data['node_links']);
        $tree[$cid] = $data['tree'];
    }
    return $tree[$cid];
}