MenuLinkDepthConstraintValidator.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Menu\Plugin\Validation\Constraint;

use Drupal\Core\Config\Schema\TypeResolver;
use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\Core\Menu\MenuLinkTreeInterface;
use Drupal\Core\Validation\Plugin\Validation\Constraint\RangeConstraintValidator;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\Exception\RuntimeException;

/**
 * Validates the MenuLinkDepthConstraint constraint.
 */
class MenuLinkDepthConstraintValidator extends RangeConstraintValidator implements ContainerInjectionInterface {
    public function __construct(MenuLinkTreeInterface $menuLinkTree) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function validate(mixed $value, Constraint $constraint) : void {
        assert($constraint instanceof MenuLinkDepthConstraint);
        // The depth can never exceed the maximum depth of a menu tree.
        $constraint->max = $this->menuLinkTree
            ->maxDepth();
        $base_level = $constraint->baseLevel;
        // The base level might be a dynamic name that needs to be resolved.
        if (is_string($base_level)) {
            $base_level = TypeResolver::resolveDynamicTypeName($base_level, $this->context
                ->getObject());
        }
        if (!is_numeric($base_level)) {
            throw new RuntimeException('The `base` option must be a number, or an expression that resolves to one.');
        }
        // Clamp $base_level (which is zero-based) to at least 0 and no more than
        // the maximum depth of a menu tree.
        $base_level = max(0, $base_level);
        $base_level = min($base_level, $constraint->max);
        $constraint->max -= $base_level;
        // We're validating a depth -- i.e., the number of levels in the menu tree
        // that should be visible. 0 effectively means "show only one level", but
        // it's not a valid value: we can't show 0 levels of the tree, after all (
        // the minimum number of levels we *could* show is 1). The discrepancy is
        // due to $base_level being zero-based, so adjust for that.
        if ($constraint->max === 0) {
            $constraint->max = 1;
        }
        parent::validate($value, $constraint);
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) : static {
        return new static($container->get(MenuLinkTreeInterface::class));
    }

}