final class ExportStorageManager in Drupal 8

The export storage manager dispatches an event for the export storage.

This class is not meant to be extended and is final to make sure the constructor and the getStorage method are both changed when this pattern is used in other circumstances.

Hierarchy

• class \Drupal\Core\Config\ExportStorageManager implements StorageManagerInterface uses StorageCopyTrait

1 file declares its use of ExportStorageManager

ExportStorageManagerTest.php in core/tests/Drupal/KernelTests/Core/Config/ExportStorageManagerTest.php

1 string reference to 'ExportStorageManager'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses ExportStorageManager

config.storage.export.manager in core/core.services.yml

Drupal\Core\Config\ExportStorageManager

File

core/lib/Drupal/Core/Config/ExportStorageManager.php, line 16

Namespace

Drupal\Core\Config

final class ExportStorageManager implements StorageManagerInterface {
  use StorageCopyTrait;

  /**
   * The name used to identify the lock.
   */
  const LOCK_NAME = 'config_storage_export_manager';

  /**
   * The active configuration storage.
   *
   * @var \Drupal\Core\Config\StorageInterface
   */
  protected $active;

  /**
   * The database storage.
   *
   * @var \Drupal\Core\Config\DatabaseStorage
   */
  protected $storage;

  /**
   * The event dispatcher.
   *
   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
   */
  protected $eventDispatcher;

  /**
   * The used lock backend instance.
   *
   * @var \Drupal\Core\Lock\LockBackendInterface
   */
  protected $lock;

  /**
   * ExportStorageManager constructor.
   *
   * @param \Drupal\Core\Config\StorageInterface $active
   *   The active config storage to prime the export storage.
   * @param \Drupal\Core\Database\Connection $connection
   *   The database connection.
   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
   *   The event dispatcher.
   * @param \Drupal\Core\Lock\LockBackendInterface $lock
   *   The used lock backend instance.
   */
  public function __construct(StorageInterface $active, Connection $connection, EventDispatcherInterface $event_dispatcher, LockBackendInterface $lock) {
    $this->active = $active;
    $this->eventDispatcher = $event_dispatcher;
    $this->lock = $lock;

    // The point of this service is to provide the storage and dispatch the
    // event when needed, so the storage itself can not be a service.
    $this->storage = new DatabaseStorage($connection, 'config_export');
  }

  /**
   * {@inheritdoc}
   */
  public function getStorage() {

    // Acquire a lock for the request to assert that the storage does not change
    // when a concurrent request transforms the storage.
    if (!$this->lock
      ->acquire(self::LOCK_NAME)) {
      $this->lock
        ->wait(self::LOCK_NAME);
      if (!$this->lock
        ->acquire(self::LOCK_NAME)) {
        throw new StorageTransformerException("Cannot acquire config export transformer lock.");
      }
    }
    self::replaceStorageContents($this->active, $this->storage);
    $this->eventDispatcher
      ->dispatch(ConfigEvents::STORAGE_TRANSFORM_EXPORT, new StorageTransformEvent($this->storage));
    return new ReadOnlyStorage($this->storage);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
ExportStorageManager::$active	protected	property	The active configuration storage.
ExportStorageManager::$eventDispatcher	protected	property	The event dispatcher.
ExportStorageManager::$lock	protected	property	The used lock backend instance.
ExportStorageManager::$storage	protected	property	The database storage.
ExportStorageManager::getStorage	public	function	Get the config storage. Overrides StorageManagerInterface::getStorage
ExportStorageManager::LOCK_NAME		constant	The name used to identify the lock.
ExportStorageManager::__construct	public	function	ExportStorageManager constructor.
StorageCopyTrait::replaceStorageContents	protected static	function	Copy the configuration from one storage to another and remove stale items.