class ImageStyleStorage

class ImageStyleStorage extends ConfigEntityStorage implements ImageStyleStorageInterface {
    
    /**
     * Image style replacement memory storage.
     *
     * This value is not stored in the backend. It's used during the deletion of
     * an image style to save the replacement image style in the same request. The
     * value is used later, when resolving dependencies.
     *
     * @var string[]
     *
     * @see \Drupal\image\Form\ImageStyleDeleteForm::submitForm()
     */
    protected $replacement = [];
    
    /**
     * {@inheritdoc}
     */
    public function setReplacementId($name, $replacement) {
        $this->replacement[$name] = $replacement;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getReplacementId($name) {
        return $this->replacement[$name] ?? NULL;
    }
    
    /**
     * {@inheritdoc}
     */
    public function clearReplacementId($name) {
        unset($this->replacement[$name]);
    }

}