class ProcessedText

class ProcessedText extends RenderElementBase {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        $class = static::class;
        return [
            '#text' => '',
            '#format' => NULL,
            '#filter_types_to_skip' => [],
            '#langcode' => '',
            '#pre_render' => [
                [
                    $class,
                    'preRenderText',
                ],
            ],
        ];
    }
    
    /**
     * Pre-render callback: Renders a processed text element into #markup.
     *
     * Runs all the enabled filters on a piece of text.
     *
     * Note: Because filters can inject JavaScript or execute PHP code, security
     * is vital here. When a user supplies a text format, you should validate it
     * using $format->access() before accepting/using it. This is normally done in
     * the validation stage of the Form API. You should for example never make a
     * preview of content in a disallowed format.
     *
     * @param array $element
     *   A structured array with the following key-value pairs:
     *   - #text: containing the text to be filtered
     *   - #format: containing the machine name of the filter format to be used to
     *     filter the text. Defaults to the fallback format.
     *   - #langcode: the language code of the text to be filtered, e.g. 'en' for
     *     English. This allows filters to be language-aware so language-specific
     *     text replacement can be implemented. Defaults to an empty string.
     *   - #filter_types_to_skip: an array of filter types to skip, or an empty
     *     array (default) to skip no filter types. All of the format's filters
     *     will be applied, except for filters of the types that are marked to be
     *     skipped. FilterInterface::TYPE_HTML_RESTRICTOR is the only type that
     *     cannot be skipped.
     *
     * @return array
     *   The passed-in element with the filtered text in '#markup'.
     *
     * @ingroup sanitization
     */
    public static function preRenderText($element) {
        $format_id = $element['#format'];
        $filter_types_to_skip = $element['#filter_types_to_skip'];
        $text = $element['#text'];
        $langcode = $element['#langcode'];
        if (!isset($format_id)) {
            $filter_settings = static::configFactory()->get('filter.settings');
            $format_id = $filter_settings->get('fallback_format');
            // Ensure 'filter.settings' cacheability is respected.
            CacheableMetadata::createFromRenderArray($element)->addCacheableDependency($filter_settings)
                ->applyTo($element);
        }
        
        /** @var \Drupal\filter\Entity\FilterFormat $format **/
        $format = FilterFormat::load($format_id);
        // If the requested text format doesn't exist or its disabled, the text
        // cannot be filtered.
        if (!$format || !$format->status()) {
            $message = !$format ? 'Missing text format: %format.' : 'Disabled text format: %format.';
            static::logger('filter')->alert($message, [
                '%format' => $format_id,
            ]);
            $element['#markup'] = '';
            return $element;
        }
        $filter_must_be_applied = function (FilterInterface $filter) use ($filter_types_to_skip) {
            $enabled = $filter->status === TRUE;
            $type = $filter->getType();
            // Prevent FilterInterface::TYPE_HTML_RESTRICTOR from being skipped.
            $filter_type_must_be_applied = $type == FilterInterface::TYPE_HTML_RESTRICTOR || !in_array($type, $filter_types_to_skip);
            return $enabled && $filter_type_must_be_applied;
        };
        // Convert all Windows and Mac newlines to a single newline, so filters only
        // need to deal with one possibility.
        $text = str_replace([
            "\r\n",
            "\r",
        ], "\n", $text);
        // Get a complete list of filters, ordered properly.
        
        /** @var \Drupal\filter\Plugin\FilterInterface[] $filters **/
        $filters = $format->filters();
        // Give filters a chance to escape HTML-like data such as code or formulas.
        foreach ($filters as $filter) {
            if ($filter_must_be_applied($filter)) {
                $text = $filter->prepare($text, $langcode);
            }
        }
        // Perform filtering.
        $metadata = BubbleableMetadata::createFromRenderArray($element);
        foreach ($filters as $filter) {
            if ($filter_must_be_applied($filter)) {
                $result = $filter->process($text, $langcode);
                $metadata = $metadata->merge($result);
                $text = $result->getProcessedText();
            }
        }
        // Filtering and sanitizing have been done in
        // \Drupal\filter\Plugin\FilterInterface. $text is not guaranteed to be
        // safe, but it has been passed through the filter system and checked with
        // a text format, so it must be printed as is. (See the note about security
        // in the method documentation above.)
        $element['#markup'] = FilteredMarkup::create($text);
        // Set the updated bubbleable rendering metadata and the text format's
        // cache tag.
        $metadata->applyTo($element);
        $element['#cache']['tags'] = Cache::mergeTags($element['#cache']['tags'], $format->getCacheTags());
        return $element;
    }
    
    /**
     * Wraps a logger channel.
     *
     * @param string $channel
     *   The name of the channel.
     *
     * @return \Psr\Log\LoggerInterface
     *   The logger for this channel.
     */
    protected static function logger($channel) {
        return \Drupal::logger($channel);
    }
    
    /**
     * Wraps the config factory.
     *
     * @return \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected static function configFactory() {
        return \Drupal::configFactory();
    }

}