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

<?php

/**
 * @file
 * Provides the jQuery UI plug-in to other Drupal modules.
 *
 * This module doesn't do too much, but it is a central location for any other
 * modules that implement the JQuery UI library. It ensures that multiple
 * modules will all include the same library script just once on any given page.
 */

/**
 * Add the specified jQuery UI library files to this page.
 *
 * The ui.core file is always included automatically, as well as the
 * effects.core file if any of the effects libraries are used.
 *
 * @param $files
 *   An array of what additional files (other than UI core) should be loaded
 *   on the page, or a string with a single file name.
 */
function jquery_ui_add($files = array()) {
  static $loaded_files, $ui_core, $effects_core;

  $jquery_ui_path = jquery_ui_get_path();
  if ($jquery_ui_path === FALSE) {
    return FALSE;
  }
  $jquery_ui_path .= '/ui';
  $compression = variable_get('jquery_update_compression_type', 'mini');

  // Convert file to an array if it's not one already, to compensate for
  // lazy developers. ;)
  if (!is_array($files)) {
    $files = array($files);
  }

  // If core hasn't been added yet, add it.
  if (!isset($ui_core)) {
    $ui_core = TRUE;
    jquery_ui_add(array('ui.core'));
  }

  // Loop through list of files to include and add them to the page.
  foreach ($files as $file) {
    // Any effects files require the effects core file.
    if (!isset($effects_core) && strpos($file, 'effects.') === 0) {
      $effects_core = TRUE;
      jquery_ui_add(array('effects.core'));
    }

    // Load other files.
    if (!isset($loaded_files[$file])) {
      switch ($compression) {
        case 'none':
          $file_path = "$file.js";
          break;

        case 'pack':
          $file_path = "packed/$file.packed.js";
          break;

        case 'mini':
        default:
          $file_path = "minified/$file.min.js";
          break;
      }
      $js_path = $jquery_ui_path . '/' . $file_path;
      drupal_add_js($js_path);
      $loaded_files[$file] = $js_path;
    }
  }
}

/**
 * Returns the path to the jQuery UI library or FALSE if not found.
 */
function jquery_ui_get_path() {
  static $path;

  if (isset($path)) {
    return $path;
  }
  $path = FALSE;

  // Libraries API integration.
  if (function_exists('libraries_get_path')) {
    $path = libraries_get_path('jquery.ui');
    // Libraries API 1.x returns a default path; 2.x returns FALSE.
    if ($path !== FALSE && !file_exists($path)) {
      $path = FALSE;
    }
  }
  // Manually check sites/all/libraries in case Libraries API is not available.
  elseif (file_exists('./sites/all/libraries/jquery.ui')) {
    $path = 'sites/all/libraries/jquery.ui';
  }

  // Check the module directory for backwards compatibility if other methods
  // failed.
  if (!$path) {
    // drupal_get_path() is not available during Drupal installation.
    if (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'install') {
      $path = drupal_substr(dirname(__FILE__), drupal_strlen(getcwd()) + 1);
      $path = strtr($path, '\\', '/');
      $path .= '/jquery.ui';
    }
    else {
      $path = drupal_get_path('module', 'jquery_ui') . '/jquery.ui';
    }
    if (!file_exists($path)) {
      $path = FALSE;
    }
  }

  return $path;
}

/**
 * Return the version of jQuery UI installed.
 */
function jquery_ui_get_version() {
  $version = 0;

  $path = jquery_ui_get_path();
  if ($path === FALSE) {
    return $version;
  }
  $file = $path . '/version.txt';
  if (file_exists($file)) {
    $version = file_get_contents($file);
  }

  return $version;
}