modules/admin_menu/admin_menu.module

<?php
// $Id: admin_menu.module,v 1.102 2009/10/28 13:28:16 sun Exp $

/**
 * @file
 * Render an administrative menu as a dropdown menu at the top of the window.
 */

/**
 * Implementation of hook_help().
 */
function admin_menu_help($path, $arg) {
  switch ($path) {
    case 'admin/settings/admin_menu':
      return t('The administration menu module provides a dropdown menu arranged for one- or two-click access to most administrative tasks and other common destinations (to users with the proper permissions). Use the settings below to customize the appearance of the menu.');

    case 'admin/help#admin_menu':
      $output = '';
      $output .= '<p>' . t('The administration menu module provides a dropdown menu arranged for one- or two-click access to most administrative tasks and other common destinations (to users with the proper permissions). Administration menu also displays the number of anonymous and authenticated users, and allows modules to add their own custom menu items. Integration with the menu varies from module to module; the contributed module <a href="@drupal">Devel</a>, for instance, makes strong use of the administration menu module to provide quick access to development tools.', array('@drupal' => 'http://drupal.org/project/devel')) . '</p>';
      $output .= '<p>' . t('The administration menu <a href="@settings">settings page</a> allows you to modify some elements of the menu\'s behavior and appearance. Since the appearance of the menu is dependent on your site theme, substantial customizations require modifications to your site\'s theme and CSS files. See the advanced module README.txt file for more information on theme and CSS customizations.', array('@settings' => url('admin/settings/admin_menu'))) . '</p>';
      $output .= '<p>' . t('The menu items displayed in the administration menu depend upon the actual permissions of the viewer. First, the administration menu is only displayed to users in roles with the <em>Access administration menu</em> (admin_menu module) permission. Second, a user must be a member of a role with the <em>Access administration pages</em> (system module) permission to view administrative links. And, third, only currently permitted links are displayed; for example, if a user is not a member of a role with the permissions <em>Administer permissions</em> (user module) and <em>Administer users</em> (user module), the <em>User management</em> menu item is not displayed.') . '</p>';
      return $output;
  }
}

/**
 * Implementation of hook_permission().
 */
function admin_menu_permission() {
  return array(
    'access administration menu' => array(
      'title' => t('Access administration menu'),
      'description' => t('Display the administration menu at the top of each page.'),
    ),
    'display drupal links' => array(
      'title' => t('Display Drupal links'),
      'description' => t('Provide Drupal.org links in the administration menu.'),
    ),
  );
}

/**
 * Implementation of hook_theme().
 */
function admin_menu_theme() {
  return array(
    'admin_menu_links' => array(
      'render element' => 'elements',
    ),
    'admin_menu_icon' => array(
      'variables' => array(),
      'file' => 'admin_menu.inc',
    ),
  );
}

/**
 * Implementation of hook_menu().
 */
function admin_menu_menu() {
  // AJAX callback.
  // @see http://drupal.org/project/js
  $items['js/admin_menu/cache'] = array(
    'page callback' => 'admin_menu_js_cache',
    'access arguments' => array('access administration menu'),
    'type' => MENU_CALLBACK,
  );
  // Module settings.
  $items['admin/config/administration'] = array(
    'title' => 'Administration',
    'description' => 'Administration tools.',
    'page callback' => 'system_admin_menu_block_page',
    'access arguments' => array('access administration pages'),
    'file' => 'system.admin.inc',
    'file path' => drupal_get_path('module', 'system'),
  );
  $items['admin/config/administration/admin_menu'] = array(
    'title' => 'Administration menu',
    'description' => 'Adjust administration menu settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('admin_menu_theme_settings'),
    'access arguments' => array('administer site configuration'),
    'file' => 'admin_menu.inc',
  );
  // Menu link callbacks.
  $items['admin_menu/toggle-modules'] = array(
    'page callback' => 'admin_menu_toggle_modules',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_CALLBACK,
    'file' => 'admin_menu.inc',
  );
  $items['admin_menu/flush-cache'] = array(
    'page callback' => 'admin_menu_flush_cache',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_CALLBACK,
    'file' => 'admin_menu.inc',
  );
  return $items;
}

/**
 * Implementation of hook_menu_alter().
 */
function admin_menu_menu_alter(&$items) {
  foreach ($items as $path => $item) {
    if (!strncmp($path, 'admin/', 6) && isset($item['type'])) {
      // To avoid namespace clashes, content-type menu items are registered
      // on a separate path. Copy these items with the proper router path and
      // make them visible.
      // @todo Is there another possibility to re-assign these items to their
      // true parent (admin/structure/types) during menu rebuild to avoid the
      // (possibly) clashing copying?
      if (strpos($path, 'admin/structure/node-type/') === 0) {
        // Copy item with fixed router path.
        $newpath = str_replace('/node-type/', '/types/', $path);
        $items[$newpath] = $item;
        // Use new item from here, but leave old intact to play nice with
        // others.
        $path = $newpath;
        // Turn MENU_CALLBACK items into visible menu items.
        if ($item['type'] == MENU_CALLBACK) {
          $items[$path]['type'] = MENU_NORMAL_ITEM;
        }
      }
      // Trick local tasks and actions into the visible menu tree.
      if ($item['type'] & MENU_IS_LOCAL_TASK) {
        $items[$path]['_visible'] = TRUE;
      }
    }
  }

  // Remove local tasks on 'admin'.
  $items['admin/by-task']['_visible'] = FALSE;
  $items['admin/by-module']['_visible'] = FALSE;
  // Move 'Add new content' to the start of the menu.
  $items['node/add']['weight'] = -15;

  // Flush client-side caches whenever the menu is rebuilt.
  admin_menu_flush_caches();
}

/**
 * Copy a menu router item to another location.
 *
 * Adjusts numeric path argument references for various menu router item
 * properties.
 *
 * @param $item
 *   The existing menu router item.
 * @param $old_path
 *   The existing path of $item, f.e. 'node/add'.
 * @param $new_path
 *   The path to copy the menu router item to, f.e. 'admin/node/add'.
 * @return
 *   The menu router item with adjusted path argument references.
 */
function admin_menu_copy_item($item, $old_path, $new_path) {
  $offset = count(explode('/', $new_path)) - count(explode('/', $old_path));
  if ($offset != 0) {
    foreach (array('page arguments', 'access arguments', 'load arguments', 'title arguments') as $args) {
      if (!empty($item[$args])) {
        foreach ($item[$args] as $key => $value) {
          if (is_numeric($value)) {
            $item[$args][$key] = $value + $offset;
          }
        }
      }
    }
  }
  return $item;
}

/**
 * Implementation of hook_init().
 *
 * We can't move this into admin_menu_footer(), because PHP-only based themes
 * like chameleon load and output scripts and stylesheets in front of
 * theme_closure(), so we ensure Admin menu's styles and scripts are loaded on
 * all pages via hook_init().
 */
function admin_menu_init() {
  if (!user_access('access administration menu') || admin_menu_suppress(FALSE)) {
    return;
  }
  // Performance: Skip this entirely for AJAX requests.
  if (strpos($_GET['q'], 'js/') === 0) {
    return;
  }
  global $user, $language;

  $path = drupal_get_path('module', 'admin_menu');
  drupal_add_css($path . '/admin_menu.css', array('preprocess' => FALSE));
  if ($user->uid == 1) {
    drupal_add_css($path . '/admin_menu.uid1.css', array('preprocess' => FALSE));
  }
  // Performance: Defer execution.
  drupal_add_js($path . '/admin_menu.js', array('defer' => TRUE));

  // Destination query strings are applied via JS.
  $settings['destination'] = drupal_http_build_query(drupal_get_destination());

  // Hash for client-side HTTP/AJAX caching.
  $cid = 'admin_menu:' . $user->uid . ':' . $language->language;
  if (!empty($_COOKIE['has_js']) && ($hash = admin_menu_cache_get($cid))) {
    $settings['hash'] = $hash;
    // The base path to use for cache requests depends on whether clean URLs
    // are enabled, whether Drupal runs in a sub-directory, and on the language
    // system configuration. url() already provides us the proper path and also
    // invokes potentially existing custom_url_rewrite() functions, which may
    // add further required components to the URL to provide context. Due to
    // those components, and since url('') returns only base_path() when clean
    // URLs are disabled, we need to use a replacement token as path.  Yuck.
    $settings['basePath'] = url('admin_menu');
  }

  $replacements = module_invoke_all('admin_menu_replacements');
  if (!empty($replacements)) {
    $settings['replacements'] = $replacements;
  }

  if ($setting = variable_get('admin_menu_margin_top', 1)) {
    $settings['margin_top'] = $setting;
  }
  if ($setting = variable_get('admin_menu_position_fixed', 0)) {
    $settings['position_fixed'] = $setting;
  }
  if ($setting = variable_get('admin_menu_tweak_tabs', 0)) {
    $settings['tweak_tabs'] = $setting;
  }
  if ($_GET['q'] == 'admin/config/modules' || strpos($_GET['q'], 'admin/config/modules/list') === 0) {
    $settings['tweak_modules'] = variable_get('admin_menu_tweak_modules', 0);
  }

  drupal_add_js(array('admin_menu' => $settings), 'setting');
}

/**
 * Suppress display of administration menu.
 *
 * This function should be called from within another module's page callback
 * (preferably using module_invoke()) when the menu should not be displayed.
 * This is useful for modules that implement popup pages or other special
 * pages where the menu would be distracting or break the layout.
 *
 * @param $set
 *   Defaults to TRUE. If called before hook_footer(), the menu will not be
 *   displayed. If FALSE is passed, the suppression state is returned.
 */
function admin_menu_suppress($set = TRUE) {
  static $suppress = FALSE;
  // drupal_add_js() must only be invoked once.
  if (!empty($set) && $suppress === FALSE) {
    $suppress = TRUE;
    drupal_add_js(array('admin_menu' => array('suppress' => 1)), 'setting');
  }
  return $suppress;
}

/**
 * Implementation of hook_page_alter().
 */
function admin_menu_page_alter(&$page) {
  $page['page_bottom']['admin_menu'] = array(
    '#markup' => admin_menu_output(),
  );
}

/**
 * Implementation of hook_js().
 */
function admin_menu_js() {
  return array(
    'cache' => array(
      'callback' => 'admin_menu_js_cache',
      'includes' => array('common', 'theme', 'unicode'),
      'dependencies' => array('devel', 'filter', 'user'),
    ),
  );
}

/**
 * Retrieve a client-side cache hash from cache.
 *
 * The hash cache is consulted more than once per request; we therefore cache
 * the results statically to avoid multiple database requests.
 *
 * This should only be used for client-side cache hashes. Use cache_menu for
 * administration menu content.
 *
 * @param $cid
 *   The cache ID of the data to retrieve.
 */
function admin_menu_cache_get($cid) {
  static $cache = array();

  if (!variable_get('admin_menu_cache_client', TRUE)) {
    return FALSE;
  }
  if (!array_key_exists($cid, $cache)) {
    $cache[$cid] = cache_get($cid, 'cache_admin_menu');
    if ($cache[$cid] && isset($cache[$cid]->data)) {
      $cache[$cid] = $cache[$cid]->data;
    }
  }

  return $cache[$cid];
}

/**
 * Store a client-side cache hash in persistent cache.
 *
 * This should only be used for client-side cache hashes. Use cache_menu for
 * administration menu content.
 *
 * @param $cid
 *   The cache ID of the data to retrieve.
 */
function admin_menu_cache_set($cid, $data) {
  if (variable_get('admin_menu_cache_client', TRUE)) {
    cache_set($cid, $data, 'cache_admin_menu');
  }
}

/**
 * Menu callback; Output administration menu for HTTP caching via AJAX request.
 */
function admin_menu_js_cache($hash = NULL) {
  // Get the rendered menu.
  $content = admin_menu_output();

  // @todo According to http://www.mnot.net/blog/2006/05/11/browser_caching,
  //   IE will only cache the content when it is compressed.
  // Determine if the client accepts gzipped data.
  if (isset($_SERVER['HTTP_ACCEPT_ENCODING'])) {
    if (strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'x-gzip') !== FALSE) {
      $encoding = 'x-gzip';
    }
    elseif (strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE) {
      $encoding = 'gzip';
    }
    // Perform gzip compression when:
    // 1) the user agent supports gzip compression.
    // 2) Drupal page compression is enabled. Sites may wish to perform the
    //    compression at the web server level (e.g. using mod_deflate).
    // 3) PHP's zlib extension is loaded, but zlib compression is disabled.
    if (isset($encoding) && variable_get('page_compression', TRUE) && extension_loaded('zlib') && zlib_get_coding_type() === FALSE) {
      // Use Vary header to tell caches to keep separate versions of the menu
      // based on user agent capabilities.
      header('Vary: Accept-Encoding');
      // Since we manually perform compression, we are also responsible to
      // send a proper encoding header.
      header('Content-Encoding: ' . $encoding);
      $content = gzencode($content, 9, FORCE_GZIP);
    }
  }

  $expires = REQUEST_TIME + (3600 * 24 * 365);
  header('Expires: ' . gmdate(DATE_RFC1123, $expires));
  header('Last-Modified: ' . gmdate(DATE_RFC1123, REQUEST_TIME));
  header('Cache-Control: max-age=' . $expires);
  header('Content-Length: ' . strlen($content));

  // Suppress Devel module.
  $GLOBALS['devel_shutdown'] = FALSE;
  echo $content;
  exit;
}

/**
 * Implementation of hook_admin_menu_replacements().
 */
function admin_menu_admin_menu_replacements() {
  $items = array();
  if ($user_count = admin_menu_get_user_count()) {
    $items['.admin-menu-users a'] = $user_count;
  }
  return $items;
}

/**
 * Return count of online anonymous/authenticated users.
 *
 * @see user_block(), user.module
 */
function admin_menu_get_user_count() {
  $interval   = REQUEST_TIME - variable_get('user_block_seconds_online', 900);
  $count_anon = drupal_session_count($interval, TRUE);
  $count_auth = drupal_session_count($interval, FALSE);

  return t('@count-anon / @count-auth', array('@count-anon' => $count_anon, '@count-auth' => $count_auth));
}

/**
 * Build the administration menu output.
 */
function admin_menu_output() {
  if (!user_access('access administration menu') || admin_menu_suppress(FALSE)) {
    return;
  }
  global $user, $language;

  $cache_server_enabled = variable_get('admin_menu_cache_server', TRUE);
  $cid = 'admin_menu:' . $user->uid . ':' . $language->language;

  // Do nothing at all here if the client supports client-side caching, the user
  // has a hash, and is NOT requesting the cache update path. Consult the hash
  // cache last, since it requires a DB request.
  // @todo Implement a sanity-check to prevent permanent double requests; i.e.
  //   what if the client-side cache fails for any reason and performs a second
  //   request on every page?
  if (!empty($_COOKIE['has_js']) && strpos($_GET['q'], 'js/admin_menu/cache') !== 0) {
    if (admin_menu_cache_get($cid)) {
      return;
    }
  }

  // Try to load and output administration menu from server-side cache.
  if ($cache_server_enabled) {
    $cache = cache_get($cid, 'cache_menu');
    if ($cache && isset($cache->data)) {
      $content = $cache->data;
    }
  }

  // Rebuild the output.
  if (!isset($content)) {
    // Add site name as CSS class for development/staging theming purposes. We
    // leverage the cookie domain instead of HTTP_HOST to account for many (but
    // not all) multi-domain setups (e.g. language-based sub-domains).
    $class_site = 'admin-menu-site' . drupal_strtolower(preg_replace('/[^a-zA-Z0-9-]/', '-', $GLOBALS['cookie_domain']));
    // @todo Always output container to harden JS-less support.
    $content['#prefix'] = '<div id="admin-menu" class="' . $class_site . '"><div id="admin-menu-wrapper"><ul>';
    $content['#suffix'] = '</ul></div></div>';

    // Load menu builder functions.
    module_load_include('inc', 'admin_menu');

    // Add administration menu.
    $content['menu'] = admin_menu_links_menu(menu_tree_all_data('management'));
    $content['menu']['#theme'] = 'admin_menu_links';
    // Ensure the menu tree is rendered between the icon and user links.
    $content['menu']['#weight'] = 0;
    // Do not sort the menu tree, since it is sorted already.
    $content['menu']['#sorted'] = TRUE;

    // Add menu additions.
    $content['icon'] = admin_menu_links_icon();
    $content['user'] = admin_menu_links_user();

    // Allow modules to alter the output.
    drupal_alter('admin_menu_output', $content);
    $content = drupal_render($content);

    // Cache the menu for this user.
    if ($cache_server_enabled) {
      cache_set($cid, $content, 'cache_menu');
    }
  }

  // Store the new hash for this user.
  if (!empty($_COOKIE['has_js'])) {
    admin_menu_cache_set($cid, md5($content));
  }

  return $content;
}

/**
 * Render a themed list of links.
 *
 * @param $variables
 *   - elements: A structured drupal_render()-array of links using the following
 *     keys:
 *     - #attributes: Optional array of attributes for the list item, processed
 *       via drupal_attributes().
 *     - #title: Title of the link, passed to l().
 *     - #href: Optional path of the link, passed to l(). When omitted, the
 *       element's '#title' is rendered without link.
 *     - #description: Optional alternative text for the link, passed to l().
 *     - #options: Optional alternative text for the link, passed to l().
 *     The array key of each child element itself is passed as path for l().
 *   - depth: Current recursion level; internal use only.
 */
function theme_admin_menu_links($variables) {
  static $destination;
  $elements = $variables['elements'];
  $depth = (isset($variables['depth']) ? $variables['depth'] : 0);

  if (!isset($destination)) {
    $destination = drupal_get_destination();
    $destination = $destination['destination'];
  }

  $output = '';
  $depth_child = $depth + 1;
  foreach (element_children($elements, TRUE) as $path) {
    // Early-return nothing if user does not have access.
    if (isset($elements[$path]['#access']) && !$elements[$path]['#access']) {
      continue;
    }
    $elements[$path] += array(
      '#attributes' => array(),
      '#options' => array(),
    );
    // Render children to determine whether this link is expandable.
    if (isset($elements[$path]['#type']) || isset($elements[$path]['#theme'])) {
      $elements[$path]['#admin_menu_depth'] = $depth_child;
      $elements[$path]['#children'] = drupal_render($elements[$path]);
    }
    else {
      // Inherit #sorted flag from parent item.
      if (isset($elements['#sorted'])) {
        $elements[$path]['#sorted'] = TRUE;
      }
      $elements[$path]['#children'] = theme('admin_menu_links', array('elements' => $elements[$path], 'depth' => $depth_child));
      if (!empty($elements[$path]['#children'])) {
        $elements[$path]['#attributes']['class'][] = 'expandable';
      }
      if (isset($elements[$path]['#attributes']['class'])) {
        $elements[$path]['#attributes']['class'] = $elements[$path]['#attributes']['class'];
      }
    }

    $link = '';
    if (isset($elements[$path]['#href'])) {
      // Strip destination query string from href attribute and apply a CSS class
      // for our JavaScript behavior instead.
      if (isset($elements[$path]['#options']['query']['destination']) && $elements[$path]['#options']['query']['destination'] == $destination) {
        unset($elements[$path]['#options']['query']['destination']);
        $elements[$path]['#options']['attributes']['class'][] = 'admin-menu-destination';
      }

      $link .= l($elements[$path]['#title'], $elements[$path]['#href'], $elements[$path]['#options']);
    }
    elseif (isset($elements[$path]['#title'])) {
      if (!empty($elements[$path]['#options']['html'])) {
        $title = $elements[$path]['#title'];
      }
      else {
        $title = check_plain($elements[$path]['#title']);
      }
      if (!empty($elements[$path]['#options']['attributes'])) {
        $link .= '<span' . drupal_attributes($elements[$path]['#options']['attributes']) . '>' . $title . '</span>';
      }
      else {
        $link .= $title;
      }
    }

    $output .= '<li' . drupal_attributes($elements[$path]['#attributes']) . '>';
    $output .= $link . $elements[$path]['#children'];
    $output .= '</li>';
  }
  // @todo #attributes probably required for UL, but already used for LI.
  // @todo Use $element['#children'] here instead.
  if ($output && $depth > 0) {
    $output = "\n<ul>" . $output . '</ul>';
  }
  return $output;
}

/**
 * Implementation of hook_translated_menu_link_alter().
 *
 * Here is where we make changes to links that need dynamic information such
 * as the current page path or the number of users.
 */
function admin_menu_translated_menu_link_alter(&$item, $map) {
  global $user, $base_url;
  static $access_all;

  if ($item['menu_name'] != 'admin_menu') {
    return;
  }

  // Check whether additional development output is enabled.
  if (!isset($access_all)) {
    $access_all = variable_get('admin_menu_show_all', 0) && module_exists('devel');
  }
  // Prepare links that would not be displayed normally.
  if ($access_all && !$item['access']) {
    $item['access'] = TRUE;
    // Prepare for http://drupal.org/node/266596
    if (!isset($item['localized_options'])) {
      _menu_item_localize($item, $map, TRUE);
    }
  }

  // Don't waste cycles altering items that are not visible
  if (!$item['access']) {
    return;
  }

  // Add developer information to all links, if enabled.
  if ($extra = variable_get('admin_menu_display', 0)) {
    $item['title'] .= ' ' . $extra[0] . ': ' . $item[$extra];
  }
}

/**
 * Implementation of hook_flush_caches().
 *
 * Flush client-side caches.
 */
function admin_menu_flush_caches() {
  // Flush cached output of admin_menu.
  cache_clear_all('admin_menu:', 'cache_menu', TRUE);
  // Flush client-side cache hashes.
  // db_table_exists() required for SimpleTest.
  if (db_table_exists('cache_admin_menu')) {
    cache_clear_all('*', 'cache_admin_menu', TRUE);
  }
}

/**
 * Implementation of hook_form_FORM_ID_alter().
 *
 * Form submit handler to flush client-side cache hashes when clean URLs are toggled.
 */
function admin_menu_form_system_clean_url_settings_alter(&$form, $form_state) {
  $form['#submit'][] = 'admin_menu_flush_caches';
}

/**
 * Implementation of hook_form_FORM_ID_alter().
 *
 * Extends Devel module with Administration menu developer settings.
 */
function admin_menu_form_devel_admin_settings_alter(&$form, &$form_state) {
  module_load_include('inc', 'admin_menu');
  _admin_menu_form_devel_admin_settings_alter($form, $form_state);
}