class ImageToolkitBase

abstract class ImageToolkitBase extends PluginBase implements ImageToolkitInterface {
    
    /**
     * The config factory.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected $configFactory;
    
    /**
     * Path of the image file.
     *
     * @var string
     */
    protected $source = '';
    
    /**
     * The image toolkit operation manager.
     *
     * @var \Drupal\Core\ImageToolkit\ImageToolkitOperationManagerInterface
     */
    protected $operationManager;
    
    /**
     * A logger instance.
     *
     * @var \Psr\Log\LoggerInterface
     */
    protected $logger;
    
    /**
     * Constructs an ImageToolkitBase object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param array $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\ImageToolkit\ImageToolkitOperationManagerInterface $operation_manager
     *   The toolkit operation manager.
     * @param \Psr\Log\LoggerInterface $logger
     *   A logger instance.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory.
     */
    public function __construct(array $configuration, $plugin_id, array $plugin_definition, ImageToolkitOperationManagerInterface $operation_manager, LoggerInterface $logger, ConfigFactoryInterface $config_factory) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->operationManager = $operation_manager;
        $this->logger = $logger;
        $this->configFactory = $config_factory;
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateConfigurationForm(array &$form, FormStateInterface $form_state) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function setSource($source) {
        // If a previous image has been loaded, there is no way to know if the
        // toolkit implementation needs to perform any additional actions like
        // freeing memory. Therefore, the source image cannot be changed once set.
        if ($this->source) {
            throw new \BadMethodCallException(__METHOD__ . '() may only be called once');
        }
        $this->source = $source;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSource() {
        return $this->source;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRequirements() {
        return [];
    }
    
    /**
     * Gets a toolkit operation plugin instance.
     *
     * @param string $operation
     *   The toolkit operation requested.
     *
     * @return \Drupal\Core\ImageToolkit\ImageToolkitOperationInterface
     *   An instance of the requested toolkit operation plugin.
     */
    protected function getToolkitOperation($operation) {
        return $this->operationManager
            ->getToolkitOperation($this, $operation);
    }
    
    /**
     * {@inheritdoc}
     */
    public function apply($operation, array $arguments = []) {
        try {
            // Get the plugin to use for the operation and apply the operation.
            return $this->getToolkitOperation($operation)
                ->apply($arguments);
        } catch (PluginNotFoundException $e) {
            $this->logger
                ->error("The selected image handling toolkit '@toolkit' can not process operation '@operation'.", [
                '@toolkit' => $this->getPluginId(),
                '@operation' => $operation,
            ]);
            return FALSE;
        } catch (\InvalidArgumentException $e) {
            $this->logger
                ->warning($e->getMessage(), []);
            return FALSE;
        }
    }

}