source: sipes/modules_contrib/jquery_ui/jquery_ui.install @ a8b1f3f

<?php

/**
 * @file
 * Installation file for jQuery UI module.
 */

/**
 * Implementation of hook_requirements().
 */
function jquery_ui_requirements($phase) {
  $requirements = array();
  $t = get_t();
  $jquery_ui_version = 0;

  if ($phase == 'install') {
    // The jquery_ui_get_version() function is in the .module file, which isn't
    // loaded yet.
    include_once dirname(__FILE__) . '/jquery_ui.module';
  }

  $requirements['jquery_ui']['title'] = $t('jQuery UI');
  if ($jquery_ui_version = jquery_ui_get_version()) {
    // Everything looks good; display the current jQuery UI version.
    $requirements['jquery_ui']['value'] = $jquery_ui_version;
    $requirements['jquery_ui']['severity'] = REQUIREMENT_OK;
  }
  else {
    // Required library wasn't found. Abort installation.
    $requirements['jquery_ui']['value'] = $t('Not found');
    // Provide a download link to the jQuery UI development bundle. The provided
    // link will list the latest 1.6.x build.
    $requirements['jquery_ui']['description'] = $t('The <a href="@jqueryui">jQuery UI</a> plugin is missing. <a href="@download">Download</a> and extract it into the <code>@directory</code> directory. Rename the extracted folder to <code>@library-folder</code>.', array(
      '@jqueryui' => 'http://jqueryui.com',
      '@download' => 'http://code.google.com/p/jquery-ui/downloads/list?q=1.6',
      '@directory' => 'sites/all/libraries',
      '@library-folder' => 'jquery.ui',
    ));
    $requirements['jquery_ui']['severity'] = REQUIREMENT_ERROR;
  }

  return $requirements;
}

/**
 * Implementation of hook_uninstall().
 */
function jquery_ui_uninstall() {
  variable_del('jquery_ui_compression_type');
}