Issue #3309314 by e0ipso: Custom render element should support Twig blocks

namespace Drupal\cl_components\Element;

use Drupal\cl_components\Component\Component;

use Drupal\cl_components\Component\ComponentDiscovery;

use Drupal\Component\Serialization\Json;

use Drupal\Component\Utility\Xss;

use Drupal\Core\Cache\CacheableMetadata;

use Drupal\Core\Render\BubbleableMetadata;

use Drupal\Core\Render\Element\RenderElement;

/**

   */

  public static function preRenderComponent(array $element): array {

    $variant = $element['#variant'] ?? '';

    $component = \Drupal::service(ComponentDiscovery::class)->find($element['#component']);

    $id = $component->getId();

    $embed_id = $variant ? $id . '--' . $variant : $id;

    $inline_template = '{% include "' . $embed_id . '" %}';

    $context_alter_callback = $element['#context_alter_callback'] ?? NULL;

    $blocks_alter_callback = $element['#blocks_alter_callback'] ?? NULL;

    $discovery = \Drupal::service(ComponentDiscovery::class);

    assert($discovery instanceof ComponentDiscovery);

    $component = $discovery->find($element['#component']);

    $context = $element['#context'] ?? [];

    $bubbleable_metadata = new BubbleableMetadata();

    $twig_blocks = $element['#twig_blocks'] ?? [];

    $trusted_blocks = $element['#trusted_blocks'] ?? FALSE;

    $inline_template = static::generateComponentTemplate(

      $component,

      $variant,

      $twig_blocks,

      $context,

      $context_alter_callback,

      $blocks_alter_callback,

      $bubbleable_metadata,

      $trusted_blocks,

    );

    $element['inline-template'] = [

      '#type' => 'inline_template',

      '#template' => $inline_template,

      '#context' => $element['#context'] ?? [],

      '#context' => $context,

    ];

    $bubbleable_metadata->applyTo($element['inline-template']);

    return $element;

  }

  /**

   * Generates the template to render the component.

   *

   * @param \Drupal\cl_components\Component\Component $component

   *   The component.

   * @param mixed $variant

   *   The variant.

   * @param array $twig_blocks

   *   The contents of any potential embed blocks.

   * @param array $context

   *   The context data.

   * @param callable|null $context_alter_callback

   *   The potential callable for altering context.

   * @param \Drupal\Core\Cache\CacheableMetadata $bubbleable_metadata

   *   The cacheable metadata.

   * @param bool $trusted_blocks

   *   Set to TRUE to render the twig blocks verbatim instead of filtering them.

   *

   * @return string

   *   The template.

   */

  private static function generateComponentTemplate(

    Component $component,

    string $variant,

    array $twig_blocks,

    array $context,

    mixed $context_alter_callback,

    mixed $blocks_alter_callback,

    CacheableMetadata $bubbleable_metadata,

    bool $trusted_blocks = FALSE,

  ): string {

    $id = $component->getId();

    $embed_id = $variant ? $id . '--' . $variant : $id;

    $template = '{# This template was dynamically generated by cl_block #}' . PHP_EOL;

    // If there is a context alter callback, execute it here.

    if (is_callable($context_alter_callback)) {

      $context = call_user_func($context_alter_callback, $context, $bubbleable_metadata);

    }

    $template .= empty($context)

      ? sprintf('{%% embed \'%s\' %%}', $embed_id)

      : sprintf('{%% embed \'%s\' with %s %%}', $embed_id, Json::encode($context));

    $template .= PHP_EOL;

    foreach ($twig_blocks as $block_name => $block_value) {

      $bl_val = is_callable($blocks_alter_callback)

        ? call_user_func($blocks_alter_callback, $block_value, $bubbleable_metadata)

        : $block_value;

      $block_build = $trusted_blocks

        ? ['#markup' => Xss::filterAdmin($bl_val)]

        : [

          '#type' => 'processed_text',

          '#text' => $bl_val,

          '#format' => is_array($block_value) ? $block_value['format'] : NULL,

        ];

      try {

        $value = \Drupal::service('renderer')->render($block_build);

      }

      catch (\Exception $e) {

        $value = $bl_val;

      }

      // Save the collected attachments before we do the stringification.

      $twig_block_metadata = BubbleableMetadata::createFromRenderArray($block_build);

      $bubbleable_metadata = $bubbleable_metadata->merge($twig_block_metadata);

      $template .= "  {% block $block_name %}" . PHP_EOL

        . "    $value" . PHP_EOL

        . "  {% endblock %}" . PHP_EOL;

    }

    $template .= '{% endembed %}' . PHP_EOL;

    return $template;

  }

  /**

   * {@inheritdoc}

   */