1 book.module | book_prev($book_link) |
Fetches the menu link for the previous page of the book.
Parameters
$book_link: A fully loaded menu link that is part of the book hierarchy.
Return value
A fully loaded menu link for the page before the one represented in: $book_link.
File
- core/
modules/ book/ book.module, line 757 - Allows users to create and organize related content in an outline.
Code
function book_prev($book_link) {
// If the parent is zero, we are at the start of a book.
if ($book_link['plid'] == 0) {
return NULL;
}
$flat = book_get_flat_menu($book_link);
reset($flat);
$curr = NULL;
do {
$prev = $curr;
$curr = current($flat);
$key = key($flat);
next($flat);
} while ($key && $key != $book_link['mlid']);
if ($key == $book_link['mlid']) {
// The previous page in the book may be a child of the previous visible link.
if ($prev['depth'] == $book_link['depth'] && $prev['has_children']) {
// The subtree will have only one link at the top level - get its data.
$tree = book_menu_subtree_data($prev);
$data = array_shift($tree);
// The link of interest is the last child - iterate to find the deepest one.
while ($data['below']) {
$data = end($data['below']);
}
return $data['link'];
}
else {
return $prev;
}
}
}