protected function BookManager::buildBookOutlineRecursive in Drupal 9

Same name and namespace in other branches

1. 8 core/modules/book/src/BookManager.php \Drupal\book\BookManager::buildBookOutlineRecursive()

Builds the data representing a book tree.

The function is a bit complex because the rendering of a link depends on the next book link.

Parameters

array $links: A flat array of book links that are part of the book. Each array element is an associative array of information about the book link, containing the fields from the {book} table. This array must be ordered depth-first.

array $parents: An array of the node ID values that are in the path from the current page to the root of the book tree.

int $depth: The minimum depth to include in the returned book tree.

Return value

array Book tree.

1 call to BookManager::buildBookOutlineRecursive()

BookManager::buildBookOutlineData in core/modules/book/src/BookManager.php

Sorts and returns the built data representing a book tree.

File

core/modules/book/src/BookManager.php, line 1127

Class

BookManager

Defines a book manager.

Namespace

Drupal\book

Code

protected function buildBookOutlineRecursive(&$links, $parents, $depth) {
  $tree = [];
  while ($item = array_pop($links)) {

    // We need to determine if we're on the path to root so we can later build
    // the correct active trail.
    $item['in_active_trail'] = in_array($item['nid'], $parents);

    // Add the current link to the tree.
    $tree[$item['nid']] = [
      'link' => $item,
      'below' => [],
    ];

    // Look ahead to the next link, but leave it on the array so it's
    // available to other recursive function calls if we return or build a
    // sub-tree.
    $next = end($links);

    // Check whether the next link is the first in a new sub-tree.
    if ($next && $next['depth'] > $depth) {

      // Recursively call buildBookOutlineRecursive to build the sub-tree.
      $tree[$item['nid']]['below'] = $this
        ->buildBookOutlineRecursive($links, $parents, $next['depth']);

      // Fetch next link after filling the sub-tree.
      $next = end($links);
    }

    // Determine if we should exit the loop and $request = return.
    if (!$next || $next['depth'] < $depth) {
      break;
    }
  }
  return $tree;
}