drupal_module__url_replace_filter/url_replace_filter.install

<?php
/**
 * @file
 * Install file for URL Replace filter.
 *
 * @author: Frédéric G. MARAND <fgm@osinet.fr>
 *
 * @license General Public License version 2.0 or later
 */

/**
 * Implementation of hook_requirements().
 *
 * Ensure the module is actually used in at least one filter.
 */
function url_replace_filter_requirements($phase) {
  if ($phase != 'runtime') {
    return array();
  }

  $formats = _url_replace_filter_get_formats();
  $filter_id = 'url_replace_filter/0';
  $count = 0;
  foreach ($formats as $format) {
    if (!empty($format->{$filter_id})) {
      $count++;
    }
  }
  $req = array(
    'title' => t('URL replace filter'),
  );
  if ($count) {
    $req['value'] = format_plural($count, "Used in 1 format.", "Used in @count formats.");
    $req['severity'] = REQUIREMENT_OK;
  } else {
    $req['value'] = t('Module is enabled but no format uses its filter. You should disable the module or use the filter in at least one format.');
    $req['severity'] = REQUIREMENT_INFO;
  }

  return array($req);
}