UpdateCacheBackendFactory.php

<?php

namespace Drupal\Core\Update;

use Drupal\Core\Cache\CacheFactoryInterface;

/**
 * Cache factory implementation for use during Drupal database updates.
 *
 * Decorates the regular runtime cache_factory service so that caches use
 * \Drupal\Core\Update\UpdateBackend.
 *
 * @see \Drupal\Core\Update\UpdateServiceProvider::register()
 */
class UpdateCacheBackendFactory implements CacheFactoryInterface {
    
    /**
     * The regular runtime cache_factory service.
     *
     * @var \Drupal\Core\Cache\CacheFactoryInterface
     */
    protected $cacheFactory;
    
    /**
     * Instantiated update cache bins.
     *
     * @var \Drupal\Core\Update\UpdateBackend[]
     */
    protected $bins = [];
    
    /**
     * UpdateCacheBackendFactory constructor.
     *
     * @param \Drupal\Core\Cache\CacheFactoryInterface $cache_factory
     *   The regular runtime cache_factory service.
     */
    public function __construct(CacheFactoryInterface $cache_factory) {
        $this->cacheFactory = $cache_factory;
    }
    
    /**
     * {@inheritdoc}
     */
    public function get($bin) {
        if (!isset($this->bins[$bin])) {
            $this->bins[$bin] = new UpdateBackend($this->cacheFactory
                ->get($bin), $bin);
        }
        return $this->bins[$bin];
    }

}