CalculatedPermissions.php

<?php

namespace Drupal\Core\Session;

use Drupal\Core\Cache\CacheableDependencyTrait;

/**
 * Represents a calculated set of permissions with cacheable metadata.
 *
 * @see \Drupal\core\Session\AccessPolicyProcessor
 */
class CalculatedPermissions implements CalculatedPermissionsInterface {
    use CacheableDependencyTrait;
    use CalculatedPermissionsTrait;
    
    /**
     * Constructs a new CalculatedPermissions.
     *
     * @param \Drupal\Core\Session\CalculatedPermissionsInterface $source
     *   The calculated permission to create a value object from.
     */
    public function __construct(CalculatedPermissionsInterface $source) {
        foreach ($source->getItems() as $item) {
            $this->items[$item->getScope()][$item->getIdentifier()] = $item;
        }
        $this->setCacheability($source);
        // The (persistent) cache contexts attached to the permissions are only
        // used internally to store the permissions in the VariationCache. We strip
        // these cache contexts when the calculated permissions get converted into a
        // value object here so that they will never bubble up by accident.
        $this->cacheContexts = [];
    }

}