_block_get_renderable_region

function _block_get_renderable_region($list = array()) {
  $weight = 0;
  $build = array();
  foreach ($list as $key => $block) {
    $config = $block->getBlock();
    $build[$key] = array(
      '#block' => $block,
      '#weight' => ++$weight,
      '#theme_wrappers' => array('block'),
    );

    // Block caching is not compatible with node_access modules. We also
    // preserve the submission of forms in blocks, by fetching from cache
    // only if the request method is 'GET' (or 'HEAD'). User 1 being out of
    // the regular 'roles define permissions' schema, it brings too many
    // chances of having unwanted output get in the cache and later be served
    // to other users. We therefore exclude user 1 from block caching.
    if (
      $GLOBALS['user']->uid == 1 ||
      count(module_implements('node_grants')) ||
      !in_array($_SERVER['REQUEST_METHOD'], array('GET', 'HEAD')) ||
      in_array($config->cache, array(DRUPAL_NO_CACHE, DRUPAL_CACHE_CUSTOM))
    ) {
      // Non-cached blocks get built immediately. Provides more content
      // that can be easily manipulated during hook_page_alter().
      $build[$key] = _block_get_renderable_block($build[$key]);
    }
    else {
      $build[$key] += array(
        '#pre_render' => array('_block_get_renderable_block'),
        '#cache' => array(
          'keys' => array($config->module, $config->delta),
          'granularity' => $config->cache,
          'bin' => 'block',
          'expire' => CACHE_TEMPORARY,
        ),
      );
    }

    // Add contextual links for this block; skip the main content block, since
    // contextual links are basically output as tabs/local tasks already. Also
    // skip the help block, since we assume that most users do not need or want
    // to perform contextual actions on the help block, and the links needlessly
    // draw attention on it.
    if ($key != 'system_main' && $key != 'system_help') {
      $build[$key]['#contextual_links']['block'] = array('admin/structure/block/manage', array($config->get('module'), $config->get('delta')));
    }
  }
  $build['#sorted'] = TRUE;
  return $build;
}