BookNodeIsRemovableAccessCheck.php

<?php

namespace Drupal\book\Access;

use Drupal\book\BookManagerInterface;
use Drupal\Core\Access\AccessResult;
use Drupal\Core\Routing\Access\AccessInterface;
use Drupal\node\NodeInterface;

/**
 * Determines whether the requested node can be removed from its book.
 */
class BookNodeIsRemovableAccessCheck implements AccessInterface {
    
    /**
     * Book Manager Service.
     *
     * @var \Drupal\book\BookManagerInterface
     */
    protected $bookManager;
    
    /**
     * Constructs a BookNodeIsRemovableAccessCheck object.
     *
     * @param \Drupal\book\BookManagerInterface $book_manager
     *   Book Manager Service.
     */
    public function __construct(BookManagerInterface $book_manager) {
        $this->bookManager = $book_manager;
    }
    
    /**
     * Checks access for removing the node from its book.
     *
     * @param \Drupal\node\NodeInterface $node
     *   The node requested to be removed from its book.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The access result.
     */
    public function access(NodeInterface $node) {
        return AccessResult::allowedIf($this->bookManager
            ->checkNodeIsRemovable($node))
            ->addCacheableDependency($node);
    }

}