drupal_render_8.inc in Render cache 7.2

File

includes/drupal_render_8.inc

<?php

/**
 * @file 
 * A straight port of Drupal 8 render functions for advanced render caching.
 */
if (!variable_get('render_cache_drupal_8_render_defined', FALSE)) {

  /**
   * Generates a render cache placeholder.
   *
   * This is used by drupal_pre_render_render_cache_placeholder() to generate
   * placeholders, but should also be called by #post_render_cache callbacks that
   * want to replace the placeholder with the final markup.
   *
   * @param string $callback
   *   The #post_render_cache callback that will replace the placeholder with its
   *   eventual markup.
   * @param array $context
   *   An array providing context for the #post_render_cache callback. This array
   *   will be altered to provide a 'token' key/value pair, if not already
   *   provided, to uniquely identify the generated placeholder.
   *
   * @return string
   *   The generated placeholder HTML.
   *
   * @throws \Exception
   *
   * @see drupal_render_cache_get()
   */
  function drupal_render_cache_generate_placeholder($callback, array &$context) {
    if (!is_callable($callback)) {
      throw new Exception(t('$callable must be a callable function or of the form service_id:method.'));
    }

    // Generate a unique token if one is not already provided.
    $context += array(
      'token' => base64_encode(drupal_random_bytes(55)),
    );
    return '<drupal-render-cache-placeholder callback="' . $callback . '" token="' . $context['token'] . '"></drupal-render-cache-placeholder>';
  }

  /**
   * Processes #post_render_cache callbacks.
   *
   * #post_render_cache callbacks may modify:
   * - #markup: to replace placeholders
   * - #attached: to add libraries or JavaScript settings
   *
   * Note that in either of these cases, #post_render_cache callbacks are
   * implicitly idempotent: a placeholder that has been replaced can't be replaced
   * again, and duplicate attachments are ignored.
   *
   * @param array &$elements
   *   The structured array describing the data being rendered.
   *
   * @see drupal_render()
   * @see drupal_render_collect_post_render_cache
   */
  function _drupal_render_process_post_render_cache(array &$elements) {
    if (isset($elements['#post_render_cache'])) {

      // Call all #post_render_cache callbacks, passing the provided context.
      foreach (array_keys($elements['#post_render_cache']) as $callback) {
        foreach ($elements['#post_render_cache'][$callback] as $context) {
          $elements = call_user_func_array($callback, array(
            $elements,
            $context,
          ));
        }
      }

      // Make sure that any attachments added in #post_render_cache callbacks are
      // also executed.
      if (isset($elements['#attached'])) {
        drupal_process_attached($elements);
      }
    }
  }
}