class ImageToolkitOperationManager

class ImageToolkitOperationManager extends DefaultPluginManager implements ImageToolkitOperationManagerInterface {
    
    /**
     * A logger instance.
     *
     * @var \Psr\Log\LoggerInterface
     */
    protected $logger;
    
    /**
     * The image toolkit manager.
     *
     * @var \Drupal\Core\ImageToolkit\ImageToolkitManager
     */
    protected $toolkitManager;
    
    /**
     * Constructs the ImageToolkitOperationManager object.
     *
     * @param \Traversable $namespaces
     *   An object that implements \Traversable which contains the root paths
     *   keyed by the corresponding namespace to look for plugin implementations.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   Cache backend instance to use.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler to invoke the alter hook with.
     * @param \Psr\Log\LoggerInterface $logger
     *   A logger instance.
     * @param \Drupal\Core\ImageToolkit\ImageToolkitManager $toolkit_manager
     *   The image toolkit manager.
     */
    public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler, LoggerInterface $logger, ImageToolkitManager $toolkit_manager) {
        parent::__construct('Plugin/ImageToolkit/Operation', $namespaces, $module_handler, 'Drupal\\Core\\ImageToolkit\\ImageToolkitOperationInterface', 'Drupal\\Core\\ImageToolkit\\Annotation\\ImageToolkitOperation');
        $this->alterInfo('image_toolkit_operation');
        $this->setCacheBackend($cache_backend, 'image_toolkit_operation_plugins');
        $this->logger = $logger;
        $this->toolkitManager = $toolkit_manager;
    }
    
    /**
     * Returns the plugin ID for a given toolkit and operation.
     *
     * @param \Drupal\Core\ImageToolkit\ImageToolkitInterface $toolkit
     *   The toolkit instance.
     * @param string $operation
     *   The operation (e.g. "crop").
     *
     * @return string
     *   The plugin ID.
     *
     * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
     *   When no plugin is available.
     */
    protected function getToolkitOperationPluginId(ImageToolkitInterface $toolkit, $operation) {
        $toolkit_id = $toolkit->getPluginId();
        $definitions = $this->getDefinitions();
        $definitions = array_filter($definitions, function ($definition) use ($toolkit_id, $operation) {
            return $definition['toolkit'] == $toolkit_id && $definition['operation'] == $operation;
        });
        if (!$definitions) {
            // If this image toolkit plugin is a derivative and returns no operation,
            // try once again with its base plugin.
            $base_toolkit_id = $toolkit->getBaseId();
            if ($toolkit_id != $base_toolkit_id && !empty($base_toolkit_id)) {
                $base_toolkit = $this->toolkitManager
                    ->createInstance($base_toolkit_id);
                return $this->getToolkitOperationPluginId($base_toolkit, $operation);
            }
            $message = new FormattableMarkup("No image operation plugin for '@toolkit' toolkit and '@operation' operation.", [
                '@toolkit' => $toolkit_id,
                '@operation' => $operation,
            ]);
            throw new PluginNotFoundException($toolkit_id . '.' . $operation, $message);
        }
        else {
            // Pickup the first plugin found.
            // @todo In https://www.drupal.org/node/2110591 we'll return here the UI
            //   selected plugin or the first found if missed.
            $definition = reset($definitions);
            return $definition['id'];
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function createInstance($plugin_id, array $configuration = [], ImageToolkitInterface $toolkit = NULL) {
        $plugin_definition = $this->getDefinition($plugin_id);
        $plugin_class = DefaultFactory::getPluginClass($plugin_id, $plugin_definition);
        return new $plugin_class($configuration, $plugin_id, $plugin_definition, $toolkit, $this->logger);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getToolkitOperation(ImageToolkitInterface $toolkit, $operation) {
        $plugin_id = $this->getToolkitOperationPluginId($toolkit, $operation);
        return $this->createInstance($plugin_id, [], $toolkit);
    }

}