AllowListConfigStorage.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Recipe;

use Drupal\Core\Config\StorageInterface;

/**
 * A read-only storage wrapper that only allows access to certain config names.
 *
 * @internal
 *   This API is experimental.
 */
final class AllowListConfigStorage implements StorageInterface {
    
    /**
     * @param \Drupal\Core\Config\StorageInterface $decorated
     *   A config storage backend to wrap around.
     * @param string[] $allowList
     *   A list of config names. Only these names will be visible, or readable,
     *   by this storage. Cannot be empty.
     */
    public function __construct(StorageInterface $decorated, array $allowList) {
        if (empty($allowList)) {
            throw new \LogicException('AllowListConfigStorage cannot be constructed with an empty allow list.');
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function exists($name) : bool {
        if (in_array($name, $this->allowList, TRUE)) {
            return $this->decorated
                ->exists($name);
        }
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function read($name) : array|false {
        return $this->exists($name) ? $this->decorated
            ->read($name) : FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function readMultiple(array $names) : array {
        $names = array_intersect($names, $this->allowList);
        return $this->decorated
            ->readMultiple($names);
    }
    
    /**
     * {@inheritdoc}
     */
    public function write($name, array $data) : never {
        throw new \BadMethodCallException('This storage is read-only.');
    }
    
    /**
     * {@inheritdoc}
     */
    public function delete($name) : never {
        throw new \BadMethodCallException('This storage is read-only.');
    }
    
    /**
     * {@inheritdoc}
     */
    public function rename($name, $new_name) : never {
        throw new \BadMethodCallException('This storage is read-only.');
    }
    
    /**
     * {@inheritdoc}
     */
    public function encode($data) : string {
        return $this->decorated
            ->encode($data);
    }
    
    /**
     * {@inheritdoc}
     */
    public function decode($raw) : array {
        return $this->decorated
            ->decode($raw);
    }
    
    /**
     * {@inheritdoc}
     */
    public function listAll($prefix = '') : array {
        return array_intersect($this->decorated
            ->listAll($prefix), $this->allowList);
    }
    
    /**
     * {@inheritdoc}
     */
    public function deleteAll($prefix = '') : never {
        throw new \BadMethodCallException('This storage is read-only.');
    }
    
    /**
     * {@inheritdoc}
     */
    public function createCollection($collection) : static {
        return new static($this->decorated
            ->createCollection($collection), $this->allowList);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAllCollectionNames() : array {
        return $this->decorated
            ->getAllCollectionNames();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCollectionName() : string {
        return $this->decorated
            ->getCollectionName();
    }

}