class DeletedFieldsRepository

class DeletedFieldsRepository implements DeletedFieldsRepositoryInterface {

  /**
   * The state key/value store.
   *
   * @var \Drupal\Core\State\StateInterface
   */
  protected $state;

  /**
   * Constructs a new deleted fields repository.
   *
   * @param \Drupal\Core\State\StateInterface $state
   *   The state key/value store.
   */
  public function __construct(StateInterface $state) {
    $this->state = $state;
  }

  /**
   * {@inheritdoc}
   */
  public function getFieldDefinitions($field_storage_unique_id = NULL) {
    $deleted_field_definitions = $this->state
      ->get('field.field.deleted', []);
    if ($field_storage_unique_id) {
      $deleted_field_definitions = array_filter($deleted_field_definitions, function (FieldDefinitionInterface $field_definition) use ($field_storage_unique_id) {
        return $field_definition
          ->getFieldStorageDefinition()
          ->getUniqueStorageIdentifier() === $field_storage_unique_id;
      });
    }
    return $deleted_field_definitions;
  }

  /**
   * {@inheritdoc}
   */
  public function getFieldStorageDefinitions() {
    return $this->state
      ->get('field.storage.deleted', []);
  }

  /**
   * {@inheritdoc}
   */
  public function addFieldDefinition(FieldDefinitionInterface $field_definition) {
    $deleted_field_definitions = $this->state
      ->get('field.field.deleted', []);
    $deleted_field_definitions[$field_definition
      ->getUniqueIdentifier()] = $field_definition;
    $this->state
      ->set('field.field.deleted', $deleted_field_definitions);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function addFieldStorageDefinition(FieldStorageDefinitionInterface $field_storage_definition) {
    $deleted_storage_definitions = $this->state
      ->get('field.storage.deleted', []);
    $deleted_storage_definitions[$field_storage_definition
      ->getUniqueStorageIdentifier()] = $field_storage_definition;
    $this->state
      ->set('field.storage.deleted', $deleted_storage_definitions);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function removeFieldDefinition(FieldDefinitionInterface $field_definition) {
    $deleted_field_definitions = $this->state
      ->get('field.field.deleted', []);
    unset($deleted_field_definitions[$field_definition
      ->getUniqueIdentifier()]);
    $this->state
      ->set('field.field.deleted', $deleted_field_definitions);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function removeFieldStorageDefinition(FieldStorageDefinitionInterface $field_storage_definition) {
    $deleted_storage_definitions = $this->state
      ->get('field.storage.deleted', []);
    unset($deleted_storage_definitions[$field_storage_definition
      ->getUniqueStorageIdentifier()]);
    $this->state
      ->set('field.storage.deleted', $deleted_storage_definitions);
    return $this;
  }

}