protected BookManager::buildBookOutlineRecursive(&$links, $parents, $depth)
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 $depth: The minimum depth to include in the returned book tree.
Return value
array Book tree.
File
- core/modules/book/src/BookManager.php, line 1049
Class
- BookManager
- Defines a book manager.
Namespace
Drupal\book
Code
protected function buildBookOutlineRecursive(&$links, $parents, $depth) {
$tree = array();
while ($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']] = array(
'link' => $item,
'below' => array(),
);
// 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;
}
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