menu.inc

Same filename in other branches
  1. 9 core/includes/menu.inc
  2. 8.9.x core/includes/menu.inc

API for the Drupal menu system.

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includes/menu.inc

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<?php


/**
 * @file
 * API for the Drupal menu system.
 */

/**
 * @defgroup menu Menu system
 * @{
 * Define the navigation menus, and route page requests to code based on URLs.
 *
 * The Drupal menu system drives both the navigation system from a user
 * perspective and the callback system that Drupal uses to respond to URLs
 * passed from the browser. For this reason, a good understanding of the
 * menu system is fundamental to the creation of complex modules. As a note,
 * this is related to, but separate from menu.module, which allows menus
 * (which in this context are hierarchical lists of links) to be customized from
 * the Drupal administrative interface.
 *
 * Drupal's menu system follows a simple hierarchy defined by paths.
 * Implementations of hook_menu() define menu items and assign them to
 * paths (which should be unique). The menu system aggregates these items
 * and determines the menu hierarchy from the paths. For example, if the
 * paths defined were a, a/b, e, a/b/c/d, f/g, and a/b/h, the menu system
 * would form the structure:
 * - a
 *   - a/b
 *     - a/b/c/d
 *     - a/b/h
 * - e
 * - f/g
 * Note that the number of elements in the path does not necessarily
 * determine the depth of the menu item in the tree.
 *
 * When responding to a page request, the menu system looks to see if the
 * path requested by the browser is registered as a menu item with a
 * callback. If not, the system searches up the menu tree for the most
 * complete match with a callback it can find. If the path a/b/i is
 * requested in the tree above, the callback for a/b would be used.
 *
 * The found callback function is called with any arguments specified
 * in the "page arguments" attribute of its menu item. The
 * attribute must be an array. After these arguments, any remaining
 * components of the path are appended as further arguments. In this
 * way, the callback for a/b above could respond to a request for
 * a/b/i differently than a request for a/b/j.
 *
 * For an illustration of this process, see page_example.module.
 *
 * Access to the callback functions is also protected by the menu system.
 * The "access callback" with an optional "access arguments" of each menu
 * item is called before the page callback proceeds. If this returns TRUE,
 * then access is granted; if FALSE, then access is denied. Default local task
 * menu items (see next paragraph) may omit this attribute to use the value
 * provided by the parent item.
 *
 * In the default Drupal interface, you will notice many links rendered as
 * tabs. These are known in the menu system as "local tasks", and they are
 * rendered as tabs by default, though other presentations are possible.
 * Local tasks function just as other menu items in most respects. It is
 * convention that the names of these tasks should be short verbs if
 * possible. In addition, a "default" local task should be provided for
 * each set. When visiting a local task's parent menu item, the default
 * local task will be rendered as if it is selected; this provides for a
 * normal tab user experience. This default task is special in that it
 * links not to its provided path, but to its parent item's path instead.
 * The default task's path is only used to place it appropriately in the
 * menu hierarchy.
 *
 * Everything described so far is stored in the menu_router table. The
 * menu_links table holds the visible menu links. By default these are
 * derived from the same hook_menu definitions, however you are free to
 * add more with menu_link_save().
 */

/**
 * @defgroup menu_flags Menu flags
 * @{
 * Flags for use in the "type" attribute of menu items.
 */

/**
 * Internal menu flag -- menu item is the root of the menu tree.
 */
define('MENU_IS_ROOT', 0x1);

/**
 * Internal menu flag -- menu item is visible in the menu tree.
 */
define('MENU_VISIBLE_IN_TREE', 0x2);

/**
 * Internal menu flag -- menu item is visible in the breadcrumb.
 */
define('MENU_VISIBLE_IN_BREADCRUMB', 0x4);

/**
 * Internal menu flag -- menu item links back to its parent.
 */
define('MENU_LINKS_TO_PARENT', 0x8);

/**
 * Internal menu flag -- menu item can be modified by administrator.
 */
define('MENU_MODIFIED_BY_ADMIN', 0x20);

/**
 * Internal menu flag -- menu item was created by administrator.
 */
define('MENU_CREATED_BY_ADMIN', 0x40);

/**
 * Internal menu flag -- menu item is a local task.
 */
define('MENU_IS_LOCAL_TASK', 0x80);

/**
 * Internal menu flag -- menu item is a local action.
 */
define('MENU_IS_LOCAL_ACTION', 0x100);

/**
 * @} End of "Menu flags".
 */

/**
 * @defgroup menu_item_types Menu item types
 * @{
 * Definitions for various menu item types.
 *
 * Menu item definitions provide one of these constants, which are shortcuts for
 * combinations of @link menu_flags Menu flags @endlink.
 */

/**
 * Menu type -- A "normal" menu item that's shown in menu and breadcrumbs.
 *
 * Normal menu items show up in the menu tree and can be moved/hidden by
 * the administrator. Use this for most menu items. It is the default value if
 * no menu item type is specified.
 */
define('MENU_NORMAL_ITEM', MENU_VISIBLE_IN_TREE | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- A hidden, internal callback, typically used for API calls.
 *
 * Callbacks simply register a path so that the correct function is fired
 * when the URL is accessed. They do not appear in menus or breadcrumbs.
 */
define('MENU_CALLBACK', 0x0);

/**
 * Menu type -- A normal menu item, hidden until enabled by an administrator.
 *
 * Modules may "suggest" menu items that the administrator may enable. They act
 * just as callbacks do until enabled, at which time they act like normal items.
 * Note for the value: 0x0010 was a flag which is no longer used, but this way
 * the values of MENU_CALLBACK and MENU_SUGGESTED_ITEM are separate.
 */
define('MENU_SUGGESTED_ITEM', MENU_VISIBLE_IN_BREADCRUMB | 0x10);

/**
 * Menu type -- A task specific to the parent item, usually rendered as a tab.
 *
 * Local tasks are menu items that describe actions to be performed on their
 * parent item. An example is the path "node/52/edit", which performs the
 * "edit" task on "node/52".
 */
define('MENU_LOCAL_TASK', MENU_IS_LOCAL_TASK | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- The "default" local task, which is initially active.
 *
 * Every set of local tasks should provide one "default" task, that links to the
 * same path as its parent when clicked.
 */
define('MENU_DEFAULT_LOCAL_TASK', MENU_IS_LOCAL_TASK | MENU_LINKS_TO_PARENT | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * Menu type -- An action specific to the parent, usually rendered as a link.
 *
 * Local actions are menu items that describe actions on the parent item such
 * as adding a new user, taxonomy term, etc.
 */
define('MENU_LOCAL_ACTION', MENU_IS_LOCAL_TASK | MENU_IS_LOCAL_ACTION | MENU_VISIBLE_IN_BREADCRUMB);

/**
 * @} End of "Menu item types".
 */

/**
 * @defgroup menu_context_types Menu context types
 * @{
 * Flags for use in the "context" attribute of menu router items.
 */

/**
 * Internal menu flag: Invisible local task.
 *
 * This flag may be used for local tasks like "Delete", so custom modules and
 * themes can alter the default context and expose the task by altering menu.
 */
define('MENU_CONTEXT_NONE', 0x0);

/**
 * Internal menu flag: Local task should be displayed in page context.
 */
define('MENU_CONTEXT_PAGE', 0x1);

/**
 * Internal menu flag: Local task should be displayed inline.
 */
define('MENU_CONTEXT_INLINE', 0x2);

/**
 * @} End of "Menu context types".
 */

/**
 * @defgroup menu_status_codes Menu status codes
 * @{
 * Status codes for menu callbacks.
 */

/**
 * Internal menu status code -- Menu item was found.
 */
define('MENU_FOUND', 1);

/**
 * Menu status code -- Not found.
 *
 * This can be used as the return value from a page callback, although it is
 * preferable to use a load function to accomplish this; see the hook_menu()
 * documentation for details.
 */
define('MENU_NOT_FOUND', 2);

/**
 * Menu status code -- Access denied.
 *
 * This can be used as the return value from a page callback, although it is
 * preferable to use an access callback to accomplish this; see the hook_menu()
 * documentation for details.
 */
define('MENU_ACCESS_DENIED', 3);

/**
 * Internal menu status code -- Menu item inaccessible because site is offline.
 */
define('MENU_SITE_OFFLINE', 4);

/**
 * Internal menu status code -- Everything is working fine.
 */
define('MENU_SITE_ONLINE', 5);

/**
 * @} End of "Menu status codes".
 */

/**
 * @defgroup menu_tree_parameters Menu tree parameters
 * @{
 * Parameters for a menu tree.
 */

/**
 * The maximum number of path elements for a menu callback
 */
define('MENU_MAX_PARTS', 9);

/**
 * The maximum depth of a menu links tree - matches the number of p columns.
 */
define('MENU_MAX_DEPTH', 9);

/**
 * @} End of "Menu tree parameters".
 */

/**
 * Reserved key to identify the most specific menu link for a given path.
 *
 * The value of this constant is a hash of the constant name. We use the hash
 * so that the reserved key is over 32 characters in length and will not
 * collide with allowed menu names:
 * @code
 * sha1('MENU_PREFERRED_LINK') = 1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91
 * @endcode
 *
 * @see menu_link_get_preferred()
 */
define('MENU_PREFERRED_LINK', '1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91');

/**
 * Returns the ancestors (and relevant placeholders) for any given path.
 *
 * For example, the ancestors of node/12345/edit are:
 * - node/12345/edit
 * - node/12345/%
 * - node/%/edit
 * - node/%/%
 * - node/12345
 * - node/%
 * - node
 *
 * To generate these, we will use binary numbers. Each bit represents a
 * part of the path. If the bit is 1, then it represents the original
 * value while 0 means wildcard. If the path is node/12/edit/foo
 * then the 1011 bitstring represents node/%/edit/foo where % means that
 * any argument matches that part. We limit ourselves to using binary
 * numbers that correspond the patterns of wildcards of router items that
 * actually exists. This list of 'masks' is built in menu_rebuild().
 *
 * @param $parts
 *   An array of path parts; for the above example,
 *   array('node', '12345', 'edit').
 *
 * @return
 *   An array which contains the ancestors and placeholders. Placeholders
 *   simply contain as many '%s' as the ancestors.
 */
function menu_get_ancestors($parts) {
    $number_parts = count($parts);
    $ancestors = array();
    $length = $number_parts - 1;
    $end = (1 << $number_parts) - 1;
    $masks = variable_get('menu_masks');
    // If the optimized menu_masks array is not available use brute force to get
    // the correct $ancestors and $placeholders returned. Do not use this as the
    // default value of the menu_masks variable to avoid building such a big
    // array.
    if (!$masks) {
        $masks = range(511, 1);
    }
    // Only examine patterns that actually exist as router items (the masks).
    foreach ($masks as $i) {
        if ($i > $end) {
            // Only look at masks that are not longer than the path of interest.
            continue;
        }
        elseif ($i < 1 << $length) {
            // We have exhausted the masks of a given length, so decrease the length.
            --$length;
        }
        $current = '';
        for ($j = $length; $j >= 0; $j--) {
            // Check the bit on the $j offset.
            if ($i & 1 << $j) {
                // Bit one means the original value.
                $current .= $parts[$length - $j];
            }
            else {
                // Bit zero means means wildcard.
                $current .= '%';
            }
            // Unless we are at offset 0, add a slash.
            if ($j) {
                $current .= '/';
            }
        }
        $ancestors[] = $current;
    }
    return $ancestors;
}

/**
 * Unserializes menu data, using a map to replace path elements.
 *
 * The menu system stores various path-related information (such as the 'page
 * arguments' and 'access arguments' components of a menu item) in the database
 * using serialized arrays, where integer values in the arrays represent
 * arguments to be replaced by values from the path. This function first
 * unserializes such menu information arrays, and then does the path
 * replacement.
 *
 * The path replacement acts on each integer-valued element of the unserialized
 * menu data array ($data) using a map array ($map, which is typically an array
 * of path arguments) as a list of replacements. For instance, if there is an
 * element of $data whose value is the number 2, then it is replaced in $data
 * with $map[2]; non-integer values in $data are left alone.
 *
 * As an example, an unserialized $data array with elements ('node_load', 1)
 * represents instructions for calling the node_load() function. Specifically,
 * this instruction says to use the path component at index 1 as the input
 * parameter to node_load(). If the path is 'node/123', then $map will be the
 * array ('node', 123), and the returned array from this function will have
 * elements ('node_load', 123), since $map[1] is 123. This return value will
 * indicate specifically that node_load(123) is to be called to load the node
 * whose ID is 123 for this menu item.
 *
 * @param $data
 *   A serialized array of menu data, as read from the database.
 * @param $map
 *   A path argument array, used to replace integer values in $data; an integer
 *   value N in $data will be replaced by value $map[N]. Typically, the $map
 *   array is generated from a call to the arg() function.
 *
 * @return
 *   The unserialized $data array, with path arguments replaced.
 */
function menu_unserialize($data, $map) {
    if ($data = unserialize($data)) {
        foreach ($data as $k => $v) {
            if (is_int($v)) {
                $data[$k] = isset($map[$v]) ? $map[$v] : '';
            }
        }
        return $data;
    }
    else {
        return array();
    }
}

/**
 * Replaces the statically cached item for a given path.
 *
 * @param $path
 *   The path.
 * @param $router_item
 *   The router item. Usually a router entry from menu_get_item() is either
 *   modified or set to a different path. This allows the navigation block,
 *   the page title, the breadcrumb, and the page help to be modified in one
 *   call.
 */
function menu_set_item($path, $router_item) {
    menu_get_item($path, $router_item);
}

/**
 * Gets a router item.
 *
 * @param $path
 *   The path; for example, 'node/5'. The function will find the corresponding
 *   node/% item and return that. Defaults to the current path.
 * @param $router_item
 *   Internal use only.
 *
 * @return
 *   The router item or, if an error occurs in _menu_translate(), FALSE. A
 *   router item is an associative array corresponding to one row in the
 *   menu_router table. The value corresponding to the key 'map' holds the
 *   loaded objects. The value corresponding to the key 'access' is TRUE if the
 *   current user can access this page. The values corresponding to the keys
 *   'title', 'page_arguments', 'access_arguments', and 'theme_arguments' will
 *   be filled in based on the database values and the objects loaded.
 */
function menu_get_item($path = NULL, $router_item = NULL) {
    $router_items =& drupal_static(__FUNCTION__);
    if (!isset($path)) {
        $path = $_GET['q'];
    }
    if (isset($router_item)) {
        $router_items[$path] = $router_item;
    }
    if (!isset($router_items[$path])) {
        // Rebuild if we know it's needed, or if the menu masks are missing which
        // occurs rarely, likely due to a race condition of multiple rebuilds.
        if (variable_get('menu_rebuild_needed', FALSE) || !variable_get('menu_masks', array())) {
            if (_menu_check_rebuild()) {
                menu_rebuild();
            }
        }
        $original_map = arg(NULL, $path);
        $parts = array_slice($original_map, 0, MENU_MAX_PARTS);
        $ancestors = menu_get_ancestors($parts);
        $router_item = db_query_range('SELECT * FROM {menu_router} WHERE path IN (:ancestors) ORDER BY fit DESC', 0, 1, array(
            ':ancestors' => $ancestors,
        ))->fetchAssoc();
        if ($router_item) {
            // Allow modules to alter the router item before it is translated and
            // checked for access.
            drupal_alter('menu_get_item', $router_item, $path, $original_map);
            $map = _menu_translate($router_item, $original_map);
            $router_item['original_map'] = $original_map;
            if ($map === FALSE) {
                $router_items[$path] = FALSE;
                return FALSE;
            }
            if ($router_item['access']) {
                $router_item['map'] = $map;
                $router_item['page_arguments'] = array_merge(menu_unserialize($router_item['page_arguments'], $map), array_slice($map, $router_item['number_parts']));
                $router_item['theme_arguments'] = array_merge(menu_unserialize($router_item['theme_arguments'], $map), array_slice($map, $router_item['number_parts']));
            }
        }
        $router_items[$path] = $router_item;
    }
    return $router_items[$path];
}

/**
 * Execute the page callback associated with the current path.
 *
 * @param $path
 *   The drupal path whose handler is to be be executed. If set to NULL, then
 *   the current path is used.
 * @param $deliver
 *   (optional) A boolean to indicate whether the content should be sent to the
 *   browser using the appropriate delivery callback (TRUE) or whether to return
 *   the result to the caller (FALSE).
 */
function menu_execute_active_handler($path = NULL, $deliver = TRUE) {
    // Check if site is offline.
    $page_callback_result = _menu_site_is_offline() ? MENU_SITE_OFFLINE : MENU_SITE_ONLINE;
    // Allow other modules to change the site status but not the path because that
    // would not change the global variable. hook_url_inbound_alter() can be used
    // to change the path. Code later will not use the $read_only_path variable.
    $read_only_path = !empty($path) ? $path : $_GET['q'];
    drupal_alter('menu_site_status', $page_callback_result, $read_only_path);
    // Only continue if the site status is not set.
    if ($page_callback_result == MENU_SITE_ONLINE) {
        if ($router_item = menu_get_item($path)) {
            if ($router_item['access']) {
                if ($router_item['include_file']) {
                    require_once DRUPAL_ROOT . '/' . $router_item['include_file'];
                }
                $page_callback_result = call_user_func_array($router_item['page_callback'], $router_item['page_arguments']);
            }
            else {
                $page_callback_result = MENU_ACCESS_DENIED;
            }
        }
        else {
            $page_callback_result = MENU_NOT_FOUND;
        }
    }
    // Deliver the result of the page callback to the browser, or if requested,
    // return it raw, so calling code can do more processing.
    if ($deliver) {
        $default_delivery_callback = isset($router_item) && $router_item ? $router_item['delivery_callback'] : NULL;
        drupal_deliver_page($page_callback_result, $default_delivery_callback);
    }
    else {
        return $page_callback_result;
    }
}

/**
 * Loads objects into the map as defined in the $item['load_functions'].
 *
 * @param $item
 *   A menu router or menu link item
 * @param $map
 *   An array of path arguments; for example, array('node', '5').
 *
 * @return
 *   Returns TRUE for success, FALSE if an object cannot be loaded.
 *   Names of object loading functions are placed in $item['load_functions'].
 *   Loaded objects are placed in $map[]; keys are the same as keys in the
 *   $item['load_functions'] array.
 *   $item['access'] is set to FALSE if an object cannot be loaded.
 */
function _menu_load_objects(&$item, &$map) {
    if ($load_functions = $item['load_functions']) {
        // If someone calls this function twice, then unserialize will fail.
        if (!is_array($load_functions)) {
            $load_functions = unserialize($load_functions);
        }
        $path_map = $map;
        foreach ($load_functions as $index => $function) {
            if ($function) {
                $value = isset($path_map[$index]) ? $path_map[$index] : '';
                if (is_array($function)) {
                    // Set up arguments for the load function. These were pulled from
                    // 'load arguments' in the hook_menu() entry, but they need
                    // some processing. In this case the $function is the key to the
                    // load_function array, and the value is the list of arguments.
                    $args = current($function);
                    $function = key($function);
                    $load_functions[$index] = $function;
                    // Some arguments are placeholders for dynamic items to process.
                    foreach ($args as $i => $arg) {
                        if ($arg === '%index') {
                            // Pass on argument index to the load function, so multiple
                            // occurrences of the same placeholder can be identified.
                            $args[$i] = $index;
                        }
                        if ($arg === '%map') {
                            // Pass on menu map by reference. The accepting function must
                            // also declare this as a reference if it wants to modify
                            // the map.
                            $args[$i] =& $map;
                        }
                        if (is_int($arg)) {
                            $args[$i] = isset($path_map[$arg]) ? $path_map[$arg] : '';
                        }
                    }
                    array_unshift($args, $value);
                    $return = call_user_func_array($function, $args);
                }
                else {
                    $return = $function($value);
                }
                // If callback returned an error or there is no callback, trigger 404.
                if ($return === FALSE) {
                    $item['access'] = FALSE;
                    $map = FALSE;
                    return FALSE;
                }
                $map[$index] = $return;
            }
        }
        $item['load_functions'] = $load_functions;
    }
    return TRUE;
}

/**
 * Checks access to a menu item using the access callback.
 *
 * @param $item
 *   A menu router or menu link item
 * @param $map
 *   An array of path arguments; for example, array('node', '5').
 *
 * @return
 *   $item['access'] becomes TRUE if the item is accessible, FALSE otherwise.
 */
function _menu_check_access(&$item, $map) {
    $item['access'] = FALSE;
    // Determine access callback, which will decide whether or not the current
    // user has access to this path.
    $callback = empty($item['access_callback']) ? 0 : trim($item['access_callback']);
    // Check for a TRUE or FALSE value.
    if (is_numeric($callback)) {
        $item['access'] = (bool) $callback;
    }
    else {
        $arguments = menu_unserialize($item['access_arguments'], $map);
        // As call_user_func_array is quite slow and user_access is a very common
        // callback, it is worth making a special case for it.
        if ($callback == 'user_access') {
            $item['access'] = count($arguments) == 1 ? user_access($arguments[0]) : user_access($arguments[0], $arguments[1]);
        }
        elseif (function_exists($callback)) {
            $item['access'] = call_user_func_array($callback, $arguments);
        }
    }
}

/**
 * Localizes the router item title using t() or another callback.
 *
 * Translate the title and description to allow storage of English title
 * strings in the database, yet display of them in the language required
 * by the current user.
 *
 * @param $item
 *   A menu router item or a menu link item.
 * @param $map
 *   The path as an array with objects already replaced. E.g., for path
 *   node/123 $map would be array('node', $node) where $node is the node
 *   object for node 123.
 * @param $link_translate
 *   TRUE if we are translating a menu link item; FALSE if we are
 *   translating a menu router item.
 *
 * @return
 *   No return value.
 *   $item['title'] is localized according to $item['title_callback'].
 *   If an item's callback is check_plain(), $item['options']['html'] becomes
 *   TRUE.
 *   $item['description'] is translated using t().
 *   When doing link translation and the $item['options']['attributes']['title']
 *   (link title attribute) matches the description, it is translated as well.
 */
function _menu_item_localize(&$item, $map, $link_translate = FALSE) {
    $callback = $item['title_callback'];
    $item['localized_options'] = $item['options'];
    // All 'class' attributes are assumed to be an array during rendering, but
    // links stored in the database may use an old string value.
    // @todo In order to remove this code we need to implement a database update
    //   including unserializing all existing link options and running this code
    //   on them, as well as adding validation to menu_link_save().
    if (isset($item['options']['attributes']['class']) && is_string($item['options']['attributes']['class'])) {
        $item['localized_options']['attributes']['class'] = explode(' ', $item['options']['attributes']['class']);
    }
    // If we are translating the title of a menu link, and its title is the same
    // as the corresponding router item, then we can use the title information
    // from the router. If it's customized, then we need to use the link title
    // itself; can't localize.
    // If we are translating a router item (tabs, page, breadcrumb), then we
    // can always use the information from the router item.
    if (!$link_translate || $item['title'] == $item['link_title']) {
        // t() is a special case. Since it is used very close to all the time,
        // we handle it directly instead of using indirect, slower methods.
        if ($callback == 't') {
            if (empty($item['title_arguments'])) {
                $item['title'] = t($item['title']);
            }
            else {
                $item['title'] = t($item['title'], menu_unserialize($item['title_arguments'], $map));
            }
        }
        elseif ($callback && function_exists($callback)) {
            if (empty($item['title_arguments'])) {
                $item['title'] = $callback($item['title']);
            }
            else {
                $item['title'] = call_user_func_array($callback, menu_unserialize($item['title_arguments'], $map));
            }
            // Avoid calling check_plain again on l() function.
            if ($callback == 'check_plain') {
                $item['localized_options']['html'] = TRUE;
            }
        }
    }
    elseif ($link_translate) {
        $item['title'] = $item['link_title'];
    }
    // Translate description, see the motivation above.
    if (!empty($item['description'])) {
        $original_description = $item['description'];
        $item['description'] = t($item['description']);
        if ($link_translate && isset($item['options']['attributes']['title']) && $item['options']['attributes']['title'] == $original_description) {
            $item['localized_options']['attributes']['title'] = $item['description'];
        }
    }
}

/**
 * Handles dynamic path translation and menu access control.
 *
 * When a user arrives on a page such as node/5, this function determines
 * what "5" corresponds to, by inspecting the page's menu path definition,
 * node/%node. This will call node_load(5) to load the corresponding node
 * object.
 *
 * It also works in reverse, to allow the display of tabs and menu items which
 * contain these dynamic arguments, translating node/%node to node/5.
 *
 * Translation of menu item titles and descriptions are done here to
 * allow for storage of English strings in the database, and translation
 * to the language required to generate the current page.
 *
 * @param $router_item
 *   A menu router item
 * @param $map
 *   An array of path arguments; for example, array('node', '5').
 * @param $to_arg
 *   Execute $item['to_arg_functions'] or not. Use only if you want to render a
 *   path from the menu table, for example tabs.
 *
 * @return
 *   Returns the map with objects loaded as defined in the
 *   $item['load_functions']. $item['access'] becomes TRUE if the item is
 *   accessible, FALSE otherwise. $item['href'] is set according to the map.
 *   If an error occurs during calling the load_functions (like trying to load
 *   a non-existent node) then this function returns FALSE.
 */
function _menu_translate(&$router_item, $map, $to_arg = FALSE) {
    if ($to_arg && !empty($router_item['to_arg_functions'])) {
        // Fill in missing path elements, such as the current uid.
        _menu_link_map_translate($map, $router_item['to_arg_functions']);
    }
    // The $path_map saves the pieces of the path as strings, while elements in
    // $map may be replaced with loaded objects.
    $path_map = $map;
    if (!empty($router_item['load_functions']) && !_menu_load_objects($router_item, $map)) {
        // An error occurred loading an object.
        $router_item['access'] = FALSE;
        return FALSE;
    }
    // Generate the link path for the page request or local tasks.
    $link_map = explode('/', $router_item['path']);
    if (isset($router_item['tab_root'])) {
        $tab_root_map = explode('/', $router_item['tab_root']);
    }
    if (isset($router_item['tab_parent'])) {
        $tab_parent_map = explode('/', $router_item['tab_parent']);
    }
    for ($i = 0; $i < $router_item['number_parts']; $i++) {
        if ($link_map[$i] == '%') {
            $link_map[$i] = $path_map[$i];
        }
        if (isset($tab_root_map[$i]) && $tab_root_map[$i] == '%') {
            $tab_root_map[$i] = $path_map[$i];
        }
        if (isset($tab_parent_map[$i]) && $tab_parent_map[$i] == '%') {
            $tab_parent_map[$i] = $path_map[$i];
        }
    }
    $router_item['href'] = implode('/', $link_map);
    $router_item['tab_root_href'] = implode('/', $tab_root_map);
    $router_item['tab_parent_href'] = implode('/', $tab_parent_map);
    $router_item['options'] = array();
    _menu_check_access($router_item, $map);
    // For performance, don't localize an item the user can't access.
    if ($router_item['access']) {
        _menu_item_localize($router_item, $map);
    }
    return $map;
}

/**
 * Translates the path elements in the map using any to_arg helper function.
 *
 * @param $map
 *   An array of path arguments; for example, array('node', '5').
 * @param $to_arg_functions
 *   An array of helper functions; for example, array(2 => 'menu_tail_to_arg').
 *
 * @see hook_menu()
 */
function _menu_link_map_translate(&$map, $to_arg_functions) {
    $to_arg_functions = unserialize($to_arg_functions);
    foreach ($to_arg_functions as $index => $function) {
        // Translate place-holders into real values.
        $arg = $function(!empty($map[$index]) ? $map[$index] : '', $map, $index);
        if (!empty($map[$index]) || isset($arg)) {
            $map[$index] = $arg;
        }
        else {
            unset($map[$index]);
        }
    }
}

/**
 * Returns a string containing the path relative to the current index.
 */
function menu_tail_to_arg($arg, $map, $index) {
    return implode('/', array_slice($map, $index));
}

/**
 * Loads the path as one string relative to the current index.
 *
 * To use this load function, you must specify the load arguments
 * in the router item as:
 * @code
 * $item['load arguments'] = array('%map', '%index');
 * @endcode
 *
 * @see search_menu().
 */
function menu_tail_load($arg, &$map, $index) {
    $arg = implode('/', array_slice($map, $index));
    $map = array_slice($map, 0, $index);
    return $arg;
}

/**
 * Provides menu link access control, translation, and argument handling.
 *
 * This function is similar to _menu_translate(), but it also does
 * link-specific preparation (such as always calling to_arg() functions).
 *
 * @param $item
 *   A menu link.
 * @param $translate
 *   (optional) Whether to try to translate a link containing dynamic path
 *   argument placeholders (%) based on the menu router item of the current
 *   path. Defaults to FALSE. Internally used for breadcrumbs.
 *
 * @return
 *   Returns the map of path arguments with objects loaded as defined in the
 *   $item['load_functions'].
 *   $item['access'] becomes TRUE if the item is accessible, FALSE otherwise.
 *   $item['href'] is generated from link_path, possibly by to_arg functions.
 *   $item['title'] is generated from link_title, and may be localized.
 *   $item['options'] is unserialized; it is also changed within the call here
 *   to $item['localized_options'] by _menu_item_localize().
 */
function _menu_link_translate(&$item, $translate = FALSE) {
    if (!is_array($item['options'])) {
        $item['options'] = unserialize($item['options']);
    }
    if ($item['external']) {
        $item['access'] = 1;
        $map = array();
        $item['href'] = $item['link_path'];
        $item['title'] = $item['link_title'];
        $item['localized_options'] = $item['options'];
    }
    else {
        // Complete the path of the menu link with elements from the current path,
        // if it contains dynamic placeholders (%).
        $map = explode('/', $item['link_path']);
        if (strpos($item['link_path'], '%') !== FALSE) {
            // Invoke registered to_arg callbacks.
            if (!empty($item['to_arg_functions'])) {
                _menu_link_map_translate($map, $item['to_arg_functions']);
            }
            elseif ($translate && ($current_router_item = menu_get_item())) {
                // If $translate is TRUE, then this link is in the active trail.
                // Only translate paths within the current path.
                if (strpos($current_router_item['path'], $item['link_path']) === 0) {
                    $count = count($map);
                    $map = array_slice($current_router_item['original_map'], 0, $count);
                    $item['original_map'] = $map;
                    if (isset($current_router_item['map'])) {
                        $item['map'] = array_slice($current_router_item['map'], 0, $count);
                    }
                    // Reset access to check it (for the first time).
                    unset($item['access']);
                }
            }
        }
        $item['href'] = implode('/', $map);
        // Skip links containing untranslated arguments.
        if (strpos($item['href'], '%') !== FALSE) {
            $item['access'] = FALSE;
            return FALSE;
        }
        // menu_tree_check_access() may set this ahead of time for links to nodes.
        if (!isset($item['access'])) {
            if (!empty($item['load_functions']) && !_menu_load_objects($item, $map)) {
                // An error occurred loading an object.
                $item['access'] = FALSE;
                return FALSE;
            }
            _menu_check_access($item, $map);
        }
        // For performance, don't localize a link the user can't access.
        if ($item['access']) {
            _menu_item_localize($item, $map, TRUE);
        }
    }
    // Allow other customizations - e.g. adding a page-specific query string to the
    // options array. For performance reasons we only invoke this hook if the link
    // has the 'alter' flag set in the options array.
    if (!empty($item['options']['alter'])) {
        drupal_alter('translated_menu_link', $item, $map);
    }
    return $map;
}

/**
 * Gets a loaded object from a router item.
 *
 * menu_get_object() provides access to objects loaded by the current router
 * item. For example, on the page node/%node, the router loads the %node object,
 * and calling menu_get_object() will return that. Normally, it is necessary to
 * specify the type of object referenced, however node is the default.
 * The following example tests to see whether the node being displayed is of the
 * "story" content type:
 * @code
 * $node = menu_get_object();
 * $story = $node->type == 'story';
 * @endcode
 *
 * @param $type
 *   Type of the object. These appear in hook_menu definitions as %type. Core
 *   provides aggregator_feed, aggregator_category, contact, filter_format,
 *   forum_term, menu, menu_link, node, taxonomy_vocabulary, user. See the
 *   relevant {$type}_load function for more on each. Defaults to node.
 * @param $position
 *   The position of the object in the path, where the first path segment is 0.
 *   For node/%node, the position of %node is 1, but for comment/reply/%node,
 *   it's 2. Defaults to 1.
 * @param $path
 *   See menu_get_item() for more on this. Defaults to the current path.
 */
function menu_get_object($type = 'node', $position = 1, $path = NULL) {
    $router_item = menu_get_item($path);
    if (isset($router_item['load_functions'][$position]) && !empty($router_item['map'][$position]) && $router_item['load_functions'][$position] == $type . '_load') {
        return $router_item['map'][$position];
    }
}

/**
 * Renders a menu tree based on the current path.
 *
 * The tree is expanded based on the current path and dynamic paths are also
 * changed according to the defined to_arg functions (for example the 'My
 * account' link is changed from user/% to a link with the current user's uid).
 *
 * @param $menu_name
 *   The name of the menu.
 *
 * @return
 *   A structured array representing the specified menu on the current page, to
 *   be rendered by drupal_render().
 */
function menu_tree($menu_name) {
    $menu_output =& drupal_static(__FUNCTION__, array());
    if (!isset($menu_output[$menu_name])) {
        $tree = menu_tree_page_data($menu_name);
        $menu_output[$menu_name] = menu_tree_output($tree);
    }
    return $menu_output[$menu_name];
}

/**
 * Returns an output structure for rendering a menu tree.
 *
 * The menu item's LI element is given one of the following classes:
 * - expanded: The menu item is showing its submenu.
 * - collapsed: The menu item has a submenu which is not shown.
 * - leaf: The menu item has no submenu.
 *
 * @param $tree
 *   A data structure representing the tree as returned from menu_tree_data.
 *
 * @return
 *   A structured array to be rendered by drupal_render().
 */
function menu_tree_output($tree) {
    $build = array();
    $items = array();
    // Pull out just the menu links we are going to render so that we
    // get an accurate count for the first/last classes.
    foreach ($tree as $data) {
        if ($data['link']['access'] && !$data['link']['hidden']) {
            $items[] = $data;
        }
    }
    $router_item = menu_get_item();
    $num_items = count($items);
    foreach ($items as $i => $data) {
        $class = array();
        if ($i == 0) {
            $class[] = 'first';
        }
        if ($i == $num_items - 1) {
            $class[] = 'last';
        }
        // Set a class for the <li>-tag. Since $data['below'] may contain local
        // tasks, only set 'expanded' class if the link also has children within
        // the current menu.
        if ($data['link']['has_children'] && $data['below']) {
            $class[] = 'expanded';
        }
        elseif ($data['link']['has_children']) {
            $class[] = 'collapsed';
        }
        else {
            $class[] = 'leaf';
        }
        // Set a class if the link is in the active trail.
        if ($data['link']['in_active_trail']) {
            $class[] = 'active-trail';
            $data['link']['localized_options']['attributes']['class'][] = 'active-trail';
        }
        // Normally, l() compares the href of every link with $_GET['q'] and sets
        // the active class accordingly. But local tasks do not appear in menu
        // trees, so if the current path is a local task, and this link is its
        // tab root, then we have to set the class manually.
        if ($router_item && $data['link']['href'] == $router_item['tab_root_href'] && $data['link']['href'] != $_GET['q']) {
            $data['link']['localized_options']['attributes']['class'][] = 'active';
        }
        // Allow menu-specific theme overrides.
        $element['#theme'] = 'menu_link__' . strtr($data['link']['menu_name'], '-', '_');
        $element['#attributes']['class'] = $class;
        $element['#title'] = $data['link']['title'];
        $element['#href'] = $data['link']['href'];
        $element['#localized_options'] = !empty($data['link']['localized_options']) ? $data['link']['localized_options'] : array();
        $element['#below'] = $data['below'] ? menu_tree_output($data['below']) : $data['below'];
        $element['#original_link'] = $data['link'];
        // Index using the link's unique mlid.
        $build[$data['link']['mlid']] = $element;
    }
    if ($build) {
        // Make sure drupal_render() does not re-order the links.
        $build['#sorted'] = TRUE;
        // Add the theme wrapper for outer markup.
        // Allow menu-specific theme overrides.
        $build['#theme_wrappers'][] = 'menu_tree__' . strtr($data['link']['menu_name'], '-', '_');
    }
    return $build;
}

/**
 * Gets the data structure representing a named menu tree.
 *
 * Since this can be the full tree including hidden items, the data returned
 * may be used for generating an an admin interface or a select.
 *
 * @param $menu_name
 *   The named menu links to return
 * @param $link
 *   A fully loaded menu link, or NULL. If a link is supplied, only the
 *   path to root will be included in the returned tree - as if this link
 *   represented the current page in a visible menu.
 * @param $max_depth
 *   Optional maximum depth of links to retrieve. Typically useful if only one
 *   or two levels of a sub tree are needed in conjunction with a non-NULL
 *   $link, in which case $max_depth should be greater than $link['depth'].
 *
 * @return
 *   An tree of menu links in an array, in the order they should be rendered.
 */
function menu_tree_all_data($menu_name, $link = NULL, $max_depth = NULL) {
    $tree =& drupal_static(__FUNCTION__, array());
    // Use $mlid as a flag for whether the data being loaded is for the whole tree.
    $mlid = isset($link['mlid']) ? $link['mlid'] : 0;
    // Generate a cache ID (cid) specific for this $menu_name, $link, $language, and depth.
    $cid = 'links:' . $menu_name . ':all:' . $mlid . ':' . $GLOBALS['language']->language . ':' . (int) $max_depth;
    if (!isset($tree[$cid])) {
        // If the static variable doesn't have the data, check {cache_menu}.
        $cache = cache_get($cid, 'cache_menu');
        if ($cache && isset($cache->data)) {
            // If the cache entry exists, it contains the parameters for
            // menu_build_tree().
            $tree_parameters = $cache->data;
        }
        // If the tree data was not in the cache, build $tree_parameters.
        if (!isset($tree_parameters)) {
            $tree_parameters = array(
                'min_depth' => 1,
                'max_depth' => $max_depth,
            );
            if ($mlid) {
                // The tree is for a single item, so we need to match the values in its
                // p columns and 0 (the top level) with the plid values of other links.
                $parents = array(
                    0,
                );
                for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
                    if (!empty($link["p{$i}"])) {
                        $parents[] = $link["p{$i}"];
                    }
                }
                $tree_parameters['expanded'] = $parents;
                $tree_parameters['active_trail'] = $parents;
                $tree_parameters['active_trail'][] = $mlid;
            }
            // Cache the tree building parameters using the page-specific cid.
            cache_set($cid, $tree_parameters, 'cache_menu');
        }
        // Build the tree using the parameters; the resulting tree will be cached
        // by _menu_build_tree()).
        $tree[$cid] = menu_build_tree($menu_name, $tree_parameters);
    }
    return $tree[$cid];
}

/**
 * Sets the path for determining the active trail of the specified menu tree.
 *
 * This path will also affect the breadcrumbs under some circumstances.
 * Breadcrumbs are built using the preferred link returned by
 * menu_link_get_preferred(). If the preferred link is inside one of the menus
 * specified in calls to menu_tree_set_path(), the preferred link will be
 * overridden by the corresponding path returned by menu_tree_get_path().
 *
 * Setting this path does not affect the main content; for that use
 * menu_set_active_item() instead.
 *
 * @param $menu_name
 *   The name of the affected menu tree.
 * @param $path
 *   The path to use when finding the active trail.
 */
function menu_tree_set_path($menu_name, $path = NULL) {
    $paths =& drupal_static(__FUNCTION__);
    if (isset($path)) {
        $paths[$menu_name] = $path;
    }
    return isset($paths[$menu_name]) ? $paths[$menu_name] : NULL;
}

/**
 * Gets the path for determining the active trail of the specified menu tree.
 *
 * @param $menu_name
 *   The menu name of the requested tree.
 *
 * @return
 *   A string containing the path. If no path has been specified with
 *   menu_tree_set_path(), NULL is returned.
 */
function menu_tree_get_path($menu_name) {
    return menu_tree_set_path($menu_name);
}

/**
 * Gets the data structure for a named menu tree, based on the current page.
 *
 * The tree order is maintained by storing each parent in an individual
 * field, see http://drupal.org/node/141866 for more.
 *
 * @param $menu_name
 *   The named menu links to return.
 * @param $max_depth
 *   (optional) The maximum depth of links to retrieve.
 * @param $only_active_trail
 *   (optional) Whether to only return the links in the active trail (TRUE)
 *   instead of all links on every level of the menu link tree (FALSE). Defaults
 *   to FALSE. Internally used for breadcrumbs only.
 *
 * @return
 *   An array of menu links, in the order they should be rendered. The array
 *   is a list of associative arrays -- these have two keys, link and below.
 *   link is a menu item, ready for theming as a link. Below represents the
 *   submenu below the link if there is one, and it is a subtree that has the
 *   same structure described for the top-level array.
 */
function menu_tree_page_data($menu_name, $max_depth = NULL, $only_active_trail = FALSE) {
    $tree =& drupal_static(__FUNCTION__, array());
    // Check if the active trail has been overridden for this menu tree.
    $active_path = menu_tree_get_path($menu_name);
    // Load the menu item corresponding to the current page.
    if ($item = menu_get_item($active_path)) {
        if (isset($max_depth)) {
            $max_depth = min($max_depth, MENU_MAX_DEPTH);
        }
        // Generate a cache ID (cid) specific for this page.
        $cid = 'links:' . $menu_name . ':page:' . $item['href'] . ':' . $GLOBALS['language']->language . ':' . (int) $item['access'] . ':' . (int) $max_depth;
        // If we are asked for the active trail only, and $menu_name has not been
        // built and cached for this page yet, then this likely means that it
        // won't be built anymore, as this function is invoked from
        // template_process_page(). So in order to not build a giant menu tree
        // that needs to be checked for access on all levels, we simply check
        // whether we have the menu already in cache, or otherwise, build a minimum
        // tree containing the breadcrumb/active trail only.
        // @see menu_set_active_trail()
        if (!isset($tree[$cid]) && $only_active_trail) {
            $cid .= ':trail';
        }
        if (!isset($tree[$cid])) {
            // If the static variable doesn't have the data, check {cache_menu}.
            $cache = cache_get($cid, 'cache_menu');
            if ($cache && isset($cache->data)) {
                // If the cache entry exists, it contains the parameters for
                // menu_build_tree().
                $tree_parameters = $cache->data;
            }
            // If the tree data was not in the cache, build $tree_parameters.
            if (!isset($tree_parameters)) {
                $tree_parameters = array(
                    'min_depth' => 1,
                    'max_depth' => $max_depth,
                );
                // Parent mlids; used both as key and value to ensure uniqueness.
                // We always want all the top-level links with plid == 0.
                $active_trail = array(
                    0 => 0,
                );
                // If the item for the current page is accessible, build the tree
                // parameters accordingly.
                if ($item['access']) {
                    // Find a menu link corresponding to the current path. If $active_path
                    // is NULL, let menu_link_get_preferred() determine the path.
                    if ($active_link = menu_link_get_preferred($active_path, $menu_name)) {
                        // The active link may only be taken into account to build the
                        // active trail, if it resides in the requested menu. Otherwise,
                        // we'd needlessly re-run _menu_build_tree() queries for every menu
                        // on every page.
                        if ($active_link['menu_name'] == $menu_name) {
                            // Use all the coordinates, except the last one because there
                            // can be no child beyond the last column.
                            for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
                                if ($active_link['p' . $i]) {
                                    $active_trail[$active_link['p' . $i]] = $active_link['p' . $i];
                                }
                            }
                            // If we are asked to build links for the active trail only, skip
                            // the entire 'expanded' handling.
                            if ($only_active_trail) {
                                $tree_parameters['only_active_trail'] = TRUE;
                            }
                        }
                    }
                    $parents = $active_trail;
                    $expanded = variable_get('menu_expanded', array());
                    // Check whether the current menu has any links set to be expanded.
                    if (!$only_active_trail && in_array($menu_name, $expanded)) {
                        // Collect all the links set to be expanded, and then add all of
                        // their children to the list as well.
                        do {
                            $result = db_select('menu_links', NULL, array(
                                'fetch' => PDO::FETCH_ASSOC,
                            ))->fields('menu_links', array(
                                'mlid',
                            ))
                                ->condition('menu_name', $menu_name)
                                ->condition('expanded', 1)
                                ->condition('has_children', 1)
                                ->condition('plid', $parents, 'IN')
                                ->condition('mlid', $parents, 'NOT IN')
                                ->execute();
                            $num_rows = FALSE;
                            foreach ($result as $item) {
                                $parents[$item['mlid']] = $item['mlid'];
                                $num_rows = TRUE;
                            }
                        } while ($num_rows);
                    }
                    $tree_parameters['expanded'] = $parents;
                    $tree_parameters['active_trail'] = $active_trail;
                }
                else {
                    $tree_parameters['expanded'] = $active_trail;
                    $tree_parameters['active_trail'] = $active_trail;
                }
                // Cache the tree building parameters using the page-specific cid.
                cache_set($cid, $tree_parameters, 'cache_menu');
            }
            // Build the tree using the parameters; the resulting tree will be cached
            // by _menu_build_tree().
            $tree[$cid] = menu_build_tree($menu_name, $tree_parameters);
        }
        return $tree[$cid];
    }
    return array();
}

/**
 * Builds a menu tree, translates links, and checks access.
 *
 * @param $menu_name
 *   The name of the menu.
 * @param $parameters
 *   (optional) An associative array of build parameters. Possible keys:
 *   - expanded: An array of parent link ids to return only menu links that are
 *     children of one of the plids in this list. If empty, the whole menu tree
 *     is built, unless 'only_active_trail' is TRUE.
 *   - active_trail: An array of mlids, representing the coordinates of the
 *     currently active menu link.
 *   - only_active_trail: Whether to only return links that are in the active
 *     trail. This option is ignored, if 'expanded' is non-empty. Internally
 *     used for breadcrumbs.
 *   - min_depth: The minimum depth of menu links in the resulting tree.
 *     Defaults to 1, which is the default to build a whole tree for a menu
 *     (excluding menu container itself).
 *   - max_depth: The maximum depth of menu links in the resulting tree.
 *   - conditions: An associative array of custom database select query
 *     condition key/value pairs; see _menu_build_tree() for the actual query.
 *
 * @return
 *   A fully built menu tree.
 */
function menu_build_tree($menu_name, array $parameters = array()) {
    // Build the menu tree.
    $data = _menu_build_tree($menu_name, $parameters);
    // Check access for the current user to each item in the tree.
    menu_tree_check_access($data['tree'], $data['node_links']);
    return $data['tree'];
}

/**
 * Builds a menu tree.
 *
 * This function may be used build the data for a menu tree only, for example
 * to further massage the data manually before further processing happens.
 * menu_tree_check_access() needs to be invoked afterwards.
 *
 * @see menu_build_tree()
 */
function _menu_build_tree($menu_name, array $parameters = array()) {
    // Static cache of already built menu trees.
    $trees =& drupal_static(__FUNCTION__, array());
    // Build the cache id; sort parents to prevent duplicate storage and remove
    // default parameter values.
    if (isset($parameters['expanded'])) {
        sort($parameters['expanded']);
    }
    $tree_cid = 'links:' . $menu_name . ':tree-data:' . $GLOBALS['language']->language . ':' . hash('sha256', serialize($parameters));
    // If we do not have this tree in the static cache, check {cache_menu}.
    if (!isset($trees[$tree_cid])) {
        $cache = cache_get($tree_cid, 'cache_menu');
        if ($cache && isset($cache->data)) {
            $trees[$tree_cid] = $cache->data;
        }
    }
    if (!isset($trees[$tree_cid])) {
        // Select the links from the table, and recursively build the tree. We
        // LEFT JOIN since there is no match in {menu_router} for an external
        // link.
        $query = db_select('menu_links', 'ml', array(
            'fetch' => PDO::FETCH_ASSOC,
        ));
        $query->addTag('translatable');
        $query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
        $query->fields('ml');
        $query->fields('m', array(
            'load_functions',
            'to_arg_functions',
            'access_callback',
            'access_arguments',
            'page_callback',
            'page_arguments',
            'delivery_callback',
            'tab_parent',
            'tab_root',
            'title',
            'title_callback',
            'title_arguments',
            'theme_callback',
            'theme_arguments',
            'type',
            'description',
        ));
        for ($i = 1; $i <= MENU_MAX_DEPTH; $i++) {
            $query->orderBy('p' . $i, 'ASC');
        }
        $query->condition('ml.menu_name', $menu_name);
        if (!empty($parameters['expanded'])) {
            $query->condition('ml.plid', $parameters['expanded'], 'IN');
        }
        elseif (!empty($parameters['only_active_trail'])) {
            $query->condition('ml.mlid', $parameters['active_trail'], 'IN');
        }
        $min_depth = isset($parameters['min_depth']) ? $parameters['min_depth'] : 1;
        if ($min_depth != 1) {
            $query->condition('ml.depth', $min_depth, '>=');
        }
        if (isset($parameters['max_depth'])) {
            $query->condition('ml.depth', $parameters['max_depth'], '<=');
        }
        // Add custom query conditions, if any were passed.
        if (isset($parameters['conditions'])) {
            foreach ($parameters['conditions'] as $column => $value) {
                $query->condition($column, $value);
            }
        }
        // Build an ordered array of links using the query result object.
        $links = array();
        foreach ($query->execute() as $item) {
            $links[] = $item;
        }
        $active_trail = isset($parameters['active_trail']) ? $parameters['active_trail'] : array();
        $data['tree'] = menu_tree_data($links, $active_trail, $min_depth);
        $data['node_links'] = array();
        menu_tree_collect_node_links($data['tree'], $data['node_links']);
        // Cache the data, if it is not already in the cache.
        cache_set($tree_cid, $data, 'cache_menu');
        $trees[$tree_cid] = $data;
    }
    return $trees[$tree_cid];
}

/**
 * Collects node links from a given menu tree recursively.
 *
 * @param $tree
 *   The menu tree you wish to collect node links from.
 * @param $node_links
 *   An array in which to store the collected node links.
 */
function menu_tree_collect_node_links(&$tree, &$node_links) {
    foreach ($tree as $key => $v) {
        if ($tree[$key]['link']['router_path'] == 'node/%') {
            $nid = substr($tree[$key]['link']['link_path'], 5);
            if (is_numeric($nid)) {
                $node_links[$nid][$tree[$key]['link']['mlid']] =& $tree[$key]['link'];
                $tree[$key]['link']['access'] = FALSE;
            }
        }
        if ($tree[$key]['below']) {
            menu_tree_collect_node_links($tree[$key]['below'], $node_links);
        }
    }
}

/**
 * Checks access and performs dynamic operations for each link in the tree.
 *
 * @param $tree
 *   The menu tree you wish to operate on.
 * @param $node_links
 *   A collection of node link references generated from $tree by
 *   menu_tree_collect_node_links().
 */
function menu_tree_check_access(&$tree, $node_links = array()) {
    if ($node_links && (user_access('access content') || user_access('bypass node access'))) {
        $nids = array_keys($node_links);
        $select = db_select('node', 'n');
        $select->addField('n', 'nid');
        // When a menu administrator who we know has permission to see unpublished
        // nodes is administering the menu, included the unpublished nodes in the
        // tree, with a special flag so that the Menu module can label them.
        // Otherwise, exclude these nodes from the tree.
        if (!empty($GLOBALS['menu_admin']) && user_access('bypass node access')) {
            $select->addField('n', 'status');
        }
        else {
            $select->condition('n.status', 1);
        }
        $select->condition('n.nid', $nids, 'IN');
        $select->addTag('node_access');
        $node_objects = $select->execute()
            ->fetchAll();
        foreach ($node_objects as $node_object) {
            foreach ($node_links[$node_object->nid] as $mlid => $link) {
                $node_links[$node_object->nid][$mlid]['access'] = TRUE;
                if (isset($node_object->status)) {
                    $node_links[$node_object->nid][$mlid]['node_unpublished'] = !$node_object->status;
                }
            }
        }
    }
    _menu_tree_check_access($tree);
}

/**
 * Sorts the menu tree and recursively checks access for each item.
 */
function _menu_tree_check_access(&$tree) {
    $new_tree = array();
    foreach ($tree as $key => $v) {
        $item =& $tree[$key]['link'];
        _menu_link_translate($item);
        if ($item['access'] || $item['in_active_trail'] && strpos($item['href'], '%') !== FALSE) {
            if ($tree[$key]['below']) {
                _menu_tree_check_access($tree[$key]['below']);
            }
            // The weights are made a uniform 5 digits by adding 50000 as an offset.
            // After _menu_link_translate(), $item['title'] has the localized link title.
            // Adding the mlid to the end of the index insures that it is unique.
            $new_tree[50000 + $item['weight'] . ' ' . $item['title'] . ' ' . $item['mlid']] = $tree[$key];
        }
    }
    // Sort siblings in the tree based on the weights and localized titles.
    ksort($new_tree);
    $tree = $new_tree;
}

/**
 * Sorts and returns the built data representing a menu tree.
 *
 * @param $links
 *   A flat array of menu links that are part of the menu. Each array element
 *   is an associative array of information about the menu link, containing the
 *   fields from the {menu_links} table, and optionally additional information
 *   from the {menu_router} table, if the menu item appears in both tables.
 *   This array must be ordered depth-first. See _menu_build_tree() for a sample
 *   query.
 * @param $parents
 *   An array of the menu link ID values that are in the path from the current
 *   page to the root of the menu tree.
 * @param $depth
 *   The minimum depth to include in the returned menu tree.
 *
 * @return
 *   An array of menu links in the form of a tree. Each item in the tree is an
 *   associative array containing:
 *   - link: The menu link item from $links, with additional element
 *     'in_active_trail' (TRUE if the link ID was in $parents).
 *   - below: An array containing the sub-tree of this item, where each element
 *     is a tree item array with 'link' and 'below' elements. This array will be
 *     empty if the menu item has no items in its sub-tree having a depth
 *     greater than or equal to $depth.
 */
function menu_tree_data(array $links, array $parents = array(), $depth = 1) {
    // Reverse the array so we can use the more efficient array_pop() function.
    $links = array_reverse($links);
    return _menu_tree_data($links, $parents, $depth);
}

/**
 * Builds the data representing a menu tree.
 *
 * The function is a bit complex because the rendering of a link depends on
 * the next menu link.
 */
function _menu_tree_data(&$links, $parents, $depth) {
    $tree = array();
    while ($item = array_pop($links)) {
        // We need to determine if we're on the path to root so we can later build
        // the correct active trail and breadcrumb.
        $item['in_active_trail'] = in_array($item['mlid'], $parents);
        // Add the current link to the tree.
        $tree[$item['mlid']] = array(
            'link' => $item,
            'below' => array(),
        );
        // Look ahead to the next link, but leave it on the array so it's available
        // to other recursive function calls if we return or build a sub-tree.
        $next = end($links);
        // Check whether the next link is the first in a new sub-tree.
        if ($next && $next['depth'] > $depth) {
            // Recursively call _menu_tree_data to build the sub-tree.
            $tree[$item['mlid']]['below'] = _menu_tree_data($links, $parents, $next['depth']);
            // Fetch next link after filling the sub-tree.
            $next = end($links);
        }
        // Determine if we should exit the loop and return.
        if (!$next || $next['depth'] < $depth) {
            break;
        }
    }
    return $tree;
}

/**
 * Implements template_preprocess_HOOK() for theme_menu_tree().
 */
function template_preprocess_menu_tree(&$variables) {
    $variables['#tree'] = $variables['tree'];
    $variables['tree'] = $variables['tree']['#children'];
}

/**
 * Returns HTML for a wrapper for a menu sub-tree.
 *
 * @param $variables
 *   An associative array containing:
 *   - tree: An HTML string containing the tree's items.
 *
 * @see template_preprocess_menu_tree()
 * @ingroup themeable
 */
function theme_menu_tree($variables) {
    return '<ul class="menu">' . $variables['tree'] . '</ul>';
}

/**
 * Returns HTML for a menu link and submenu.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: Structured array data for a menu link.
 *
 * @ingroup themeable
 */
function theme_menu_link(array $variables) {
    $element = $variables['element'];
    $sub_menu = '';
    if ($element['#below']) {
        $sub_menu = drupal_render($element['#below']);
    }
    $output = l($element['#title'], $element['#href'], $element['#localized_options']);
    return '<li' . drupal_attributes($element['#attributes']) . '>' . $output . $sub_menu . "</li>\n";
}

/**
 * Returns HTML for a single local task link.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: A render element containing:
 *     - #link: A menu link array with 'title', 'href', and 'localized_options'
 *       keys.
 *     - #active: A boolean indicating whether the local task is active.
 *
 * @ingroup themeable
 */
function theme_menu_local_task($variables) {
    $link = $variables['element']['#link'];
    $link_text = $link['title'];
    if (!empty($variables['element']['#active'])) {
        // Add text to indicate active tab for non-visual users.
        $active = '<span class="element-invisible">' . t('(active tab)') . '</span>';
        // If the link does not contain HTML already, check_plain() it now.
        // After we set 'html'=TRUE the link will not be sanitized by l().
        if (empty($link['localized_options']['html'])) {
            $link['title'] = check_plain($link['title']);
        }
        $link['localized_options']['html'] = TRUE;
        $link_text = t('!local-task-title!active', array(
            '!local-task-title' => $link['title'],
            '!active' => $active,
        ));
    }
    return '<li' . (!empty($variables['element']['#active']) ? ' class="active"' : '') . '>' . l($link_text, $link['href'], $link['localized_options']) . "</li>\n";
}

/**
 * Returns HTML for a single local action link.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: A render element containing:
 *     - #link: A menu link array with 'title', 'href', and 'localized_options'
 *       keys.
 *
 * @ingroup themeable
 */
function theme_menu_local_action($variables) {
    $link = $variables['element']['#link'];
    $output = '<li>';
    if (isset($link['href'])) {
        $output .= l($link['title'], $link['href'], isset($link['localized_options']) ? $link['localized_options'] : array());
    }
    elseif (!empty($link['localized_options']['html'])) {
        $output .= $link['title'];
    }
    else {
        $output .= check_plain($link['title']);
    }
    $output .= "</li>\n";
    return $output;
}

/**
 * Generates elements for the $arg array in the help hook.
 */
function drupal_help_arg($arg = array()) {
    // Note - the number of empty elements should be > MENU_MAX_PARTS.
    return $arg + array(
        '',
        '',
        '',
        '',
        '',
        '',
        '',
        '',
        '',
        '',
        '',
        '',
    );
}

/**
 * Returns the help associated with the active menu item.
 */
function menu_get_active_help() {
    $output = '';
    $router_path = menu_tab_root_path();
    // We will always have a path unless we are on a 403 or 404.
    if (!$router_path) {
        return '';
    }
    $arg = drupal_help_arg(arg(NULL));
    foreach (module_implements('help') as $module) {
        $function = $module . '_help';
        // Lookup help for this path.
        if ($help = $function($router_path, $arg)) {
            $output .= $help . "\n";
        }
    }
    return $output;
}

/**
 * Gets the custom theme for the current page, if there is one.
 *
 * @param $initialize
 *   This parameter should only be used internally; it is set to TRUE in order
 *   to force the custom theme to be initialized for the current page request.
 *
 * @return
 *   The machine-readable name of the custom theme, if there is one.
 *
 * @see menu_set_custom_theme()
 */
function menu_get_custom_theme($initialize = FALSE) {
    $custom_theme =& drupal_static(__FUNCTION__);
    // Skip this if the site is offline or being installed or updated, since the
    // menu system may not be correctly initialized then.
    if ($initialize && !_menu_site_is_offline(TRUE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update' && MAINTENANCE_MODE != 'install')) {
        // First allow modules to dynamically set a custom theme for the current
        // page. Since we can only have one, the last module to return a valid
        // theme takes precedence.
        $custom_themes = array_filter(module_invoke_all('custom_theme'), 'drupal_theme_access');
        if (!empty($custom_themes)) {
            $custom_theme = array_pop($custom_themes);
        }
        // If there is a theme callback function for the current page, execute it.
        // If this returns a valid theme, it will override any theme that was set
        // by a hook_custom_theme() implementation above.
        $router_item = menu_get_item();
        if (!empty($router_item['access']) && !empty($router_item['theme_callback']) && function_exists($router_item['theme_callback'])) {
            $theme_name = call_user_func_array($router_item['theme_callback'], $router_item['theme_arguments']);
            if (drupal_theme_access($theme_name)) {
                $custom_theme = $theme_name;
            }
        }
    }
    return $custom_theme;
}

/**
 * Sets a custom theme for the current page, if there is one.
 */
function menu_set_custom_theme() {
    menu_get_custom_theme(TRUE);
}

/**
 * Build a list of named menus.
 */
function menu_get_names() {
    $names =& drupal_static(__FUNCTION__);
    if (empty($names)) {
        $names = db_select('menu_links')->distinct()
            ->fields('menu_links', array(
            'menu_name',
        ))
            ->orderBy('menu_name')
            ->execute()
            ->fetchCol();
    }
    return $names;
}

/**
 * Returns an array containing the names of system-defined (default) menus.
 */
function menu_list_system_menus() {
    return array(
        'navigation' => 'Navigation',
        'management' => 'Management',
        'user-menu' => 'User menu',
        'main-menu' => 'Main menu',
    );
}

/**
 * Returns an array of links to be rendered as the Main menu.
 */
function menu_main_menu() {
    return menu_navigation_links(variable_get('menu_main_links_source', 'main-menu'));
}

/**
 * Returns an array of links to be rendered as the Secondary links.
 */
function menu_secondary_menu() {
    // If the secondary menu source is set as the primary menu, we display the
    // second level of the primary menu.
    if (variable_get('menu_secondary_links_source', 'user-menu') == variable_get('menu_main_links_source', 'main-menu')) {
        return menu_navigation_links(variable_get('menu_main_links_source', 'main-menu'), 1);
    }
    else {
        return menu_navigation_links(variable_get('menu_secondary_links_source', 'user-menu'), 0);
    }
}

/**
 * Returns an array of links for a navigation menu.
 *
 * @param $menu_name
 *   The name of the menu.
 * @param $level
 *   Optional, the depth of the menu to be returned.
 *
 * @return
 *   An array of links of the specified menu and level.
 */
function menu_navigation_links($menu_name, $level = 0) {
    // Don't even bother querying the menu table if no menu is specified.
    if (empty($menu_name)) {
        return array();
    }
    // Get the menu hierarchy for the current page.
    $tree = menu_tree_page_data($menu_name, $level + 1);
    // Go down the active trail until the right level is reached.
    while ($level-- > 0 && $tree) {
        // Loop through the current level's items until we find one that is in trail.
        while ($item = array_shift($tree)) {
            if ($item['link']['in_active_trail']) {
                // If the item is in the active trail, we continue in the subtree.
                $tree = empty($item['below']) ? array() : $item['below'];
                break;
            }
        }
    }
    // Create a single level of links.
    $router_item = menu_get_item();
    $links = array();
    foreach ($tree as $item) {
        if ($item['link']['access'] && !$item['link']['hidden']) {
            $class = '';
            $l = $item['link']['localized_options'];
            $l['href'] = $item['link']['href'];
            $l['title'] = $item['link']['title'];
            if ($item['link']['in_active_trail']) {
                $class = ' active-trail';
                $l['attributes']['class'][] = 'active-trail';
            }
            // Normally, l() compares the href of every link with $_GET['q'] and sets
            // the active class accordingly. But local tasks do not appear in menu
            // trees, so if the current path is a local task, and this link is its
            // tab root, then we have to set the class manually.
            if ($item['link']['href'] == $router_item['tab_root_href'] && $item['link']['href'] != $_GET['q']) {
                $l['attributes']['class'][] = 'active';
            }
            // Keyed with the unique mlid to generate classes in theme_links().
            $links['menu-' . $item['link']['mlid'] . $class] = $l;
        }
    }
    return $links;
}

/**
 * Collects the local tasks (tabs), action links, and the root path.
 *
 * @param $level
 *   The level of tasks you ask for. Primary tasks are 0, secondary are 1.
 *
 * @return
 *   An array containing
 *   - tabs: Local tasks for the requested level:
 *     - count: The number of local tasks.
 *     - output: The themed output of local tasks.
 *   - actions: Action links for the requested level:
 *     - count: The number of action links.
 *     - output: The themed output of action links.
 *   - root_path: The router path for the current page. If the current page is
 *     a default local task, then this corresponds to the parent tab.
 */
function menu_local_tasks($level = 0) {
    $data =& drupal_static(__FUNCTION__);
    $root_path =& drupal_static(__FUNCTION__ . ':root_path', '');
    $empty = array(
        'tabs' => array(
            'count' => 0,
            'output' => array(),
        ),
        'actions' => array(
            'count' => 0,
            'output' => array(),
        ),
        'root_path' => &$root_path,
    );
    if (!isset($data)) {
        $data = array();
        // Set defaults in case there are no actions or tabs.
        $actions = $empty['actions'];
        $tabs = array();
        $router_item = menu_get_item();
        // If this router item points to its parent, start from the parents to
        // compute tabs and actions.
        if ($router_item && $router_item['type'] & MENU_LINKS_TO_PARENT) {
            $router_item = menu_get_item($router_item['tab_parent_href']);
        }
        // If we failed to fetch a router item or the current user doesn't have
        // access to it, don't bother computing the tabs.
        if (!$router_item || !$router_item['access']) {
            return $empty;
        }
        // Get all tabs (also known as local tasks) and the root page.
        $cid = 'local_tasks:' . $router_item['tab_root'];
        if ($cache = cache_get($cid, 'cache_menu')) {
            $result = $cache->data;
        }
        else {
            $result = db_select('menu_router', NULL, array(
                'fetch' => PDO::FETCH_ASSOC,
            ))->fields('menu_router')
                ->condition('tab_root', $router_item['tab_root'])
                ->condition('context', MENU_CONTEXT_INLINE, '<>')
                ->orderBy('weight')
                ->orderBy('title')
                ->execute()
                ->fetchAll();
            cache_set($cid, $result, 'cache_menu');
        }
        $map = $router_item['original_map'];
        $children = array();
        $tasks = array();
        $root_path = $router_item['path'];
        foreach ($result as $item) {
            _menu_translate($item, $map, TRUE);
            if ($item['tab_parent']) {
                // All tabs, but not the root page.
                $children[$item['tab_parent']][$item['path']] = $item;
            }
            // Store the translated item for later use.
            $tasks[$item['path']] = $item;
        }
        // Find all tabs below the current path.
        $path = $router_item['path'];
        // Tab parenting may skip levels, so the number of parts in the path may not
        // equal the depth. Thus we use the $depth counter (offset by 1000 for ksort).
        $depth = 1001;
        $actions['count'] = 0;
        $actions['output'] = array();
        while (isset($children[$path])) {
            $tabs_current = array();
            $actions_current = array();
            $next_path = '';
            $tab_count = 0;
            $action_count = 0;
            foreach ($children[$path] as $item) {
                // Local tasks can be normal items too, so bitmask with
                // MENU_IS_LOCAL_TASK before checking.
                if (!($item['type'] & MENU_IS_LOCAL_TASK)) {
                    // This item is not a tab, skip it.
                    continue;
                }
                if ($item['access']) {
                    $link = $item;
                    // The default task is always active. As tabs can be normal items
                    // too, so bitmask with MENU_LINKS_TO_PARENT before checking.
                    if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
                        // Find the first parent which is not a default local task or action.
                        for ($p = $item['tab_parent']; ($tasks[$p]['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT; $p = $tasks[$p]['tab_parent']) {
                        }
                        // Use the path of the parent instead.
                        $link['href'] = $tasks[$p]['href'];
                        // Mark the link as active, if the current path happens to be the
                        // path of the default local task itself (i.e., instead of its
                        // tab_parent_href or tab_root_href). Normally, links for default
                        // local tasks link to their parent, but the path of default local
                        // tasks can still be accessed directly, in which case this link
                        // would not be marked as active, since l() only compares the href
                        // with $_GET['q'].
                        if ($link['href'] != $_GET['q']) {
                            $link['localized_options']['attributes']['class'][] = 'active';
                        }
                        $tabs_current[] = array(
                            '#theme' => 'menu_local_task',
                            '#link' => $link,
                            '#active' => TRUE,
                        );
                        $next_path = $item['path'];
                        $tab_count++;
                    }
                    else {
                        // Actions can be normal items too, so bitmask with
                        // MENU_IS_LOCAL_ACTION before checking.
                        if (($item['type'] & MENU_IS_LOCAL_ACTION) == MENU_IS_LOCAL_ACTION) {
                            // The item is an action, display it as such.
                            $actions_current[] = array(
                                '#theme' => 'menu_local_action',
                                '#link' => $link,
                            );
                            $action_count++;
                        }
                        else {
                            // Otherwise, it's a normal tab.
                            $tabs_current[] = array(
                                '#theme' => 'menu_local_task',
                                '#link' => $link,
                            );
                            $tab_count++;
                        }
                    }
                }
            }
            $path = $next_path;
            $tabs[$depth]['count'] = $tab_count;
            $tabs[$depth]['output'] = $tabs_current;
            $actions['count'] += $action_count;
            $actions['output'] = array_merge($actions['output'], $actions_current);
            $depth++;
        }
        $data['actions'] = $actions;
        // Find all tabs at the same level or above the current one.
        $parent = $router_item['tab_parent'];
        $path = $router_item['path'];
        $current = $router_item;
        $depth = 1000;
        while (isset($children[$parent])) {
            $tabs_current = array();
            $next_path = '';
            $next_parent = '';
            $count = 0;
            foreach ($children[$parent] as $item) {
                // Skip local actions.
                if ($item['type'] & MENU_IS_LOCAL_ACTION) {
                    continue;
                }
                if ($item['access']) {
                    $count++;
                    $link = $item;
                    // Local tasks can be normal items too, so bitmask with
                    // MENU_LINKS_TO_PARENT before checking.
                    if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
                        // Find the first parent which is not a default local task.
                        for ($p = $item['tab_parent']; ($tasks[$p]['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT; $p = $tasks[$p]['tab_parent']) {
                        }
                        // Use the path of the parent instead.
                        $link['href'] = $tasks[$p]['href'];
                        if ($item['path'] == $router_item['path']) {
                            $root_path = $tasks[$p]['path'];
                        }
                    }
                    // We check for the active tab.
                    if ($item['path'] == $path) {
                        // Mark the link as active, if the current path is a (second-level)
                        // local task of a default local task. Since this default local task
                        // links to its parent, l() will not mark it as active, as it only
                        // compares the link's href to $_GET['q'].
                        if ($link['href'] != $_GET['q']) {
                            $link['localized_options']['attributes']['class'][] = 'active';
                        }
                        $tabs_current[] = array(
                            '#theme' => 'menu_local_task',
                            '#link' => $link,
                            '#active' => TRUE,
                        );
                        $next_path = $item['tab_parent'];
                        if (isset($tasks[$next_path])) {
                            $next_parent = $tasks[$next_path]['tab_parent'];
                        }
                    }
                    else {
                        $tabs_current[] = array(
                            '#theme' => 'menu_local_task',
                            '#link' => $link,
                        );
                    }
                }
            }
            $path = $next_path;
            $parent = $next_parent;
            $tabs[$depth]['count'] = $count;
            $tabs[$depth]['output'] = $tabs_current;
            $depth--;
        }
        // Sort by depth.
        ksort($tabs);
        // Remove the depth, we are interested only in their relative placement.
        $tabs = array_values($tabs);
        $data['tabs'] = $tabs;
        // Allow modules to alter local tasks or dynamically append further tasks.
        drupal_alter('menu_local_tasks', $data, $router_item, $root_path);
    }
    if (isset($data['tabs'][$level])) {
        return array(
            'tabs' => $data['tabs'][$level],
            'actions' => $data['actions'],
            'root_path' => $root_path,
        );
    }
    elseif (!empty($data['actions']['output'])) {
        return array(
            'actions' => $data['actions'],
        ) + $empty;
    }
    return $empty;
}

/**
 * Retrieves contextual links for a path based on registered local tasks.
 *
 * This leverages the menu system to retrieve the first layer of registered
 * local tasks for a given system path. All local tasks of the tab type
 * MENU_CONTEXT_INLINE are taken into account.
 *
 * For example, when considering the following registered local tasks:
 * - node/%node/view (default local task) with no 'context' defined
 * - node/%node/edit with context: MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE
 * - node/%node/revisions with context: MENU_CONTEXT_PAGE
 * - node/%node/report-as-spam with context: MENU_CONTEXT_INLINE
 *
 * If the path "node/123" is passed to this function, then it will return the
 * links for 'edit' and 'report-as-spam'.
 *
 * @param $module
 *   The name of the implementing module. This is used to prefix the key for
 *   each contextual link, which is transformed into a CSS class during
 *   rendering by theme_links(). For example, if $module is 'block' and the
 *   retrieved local task path argument is 'edit', then the resulting CSS class
 *   will be 'block-edit'.
 * @param $parent_path
 *   The static menu router path of the object to retrieve local tasks for, for
 *   example 'node' or 'admin/structure/block/manage'.
 * @param $args
 *   A list of dynamic path arguments to append to $parent_path to form the
 *   fully-qualified menu router path; for example, array(123) for a certain
 *   node or array('system', 'navigation') for a certain block.
 *
 * @return
 *   A list of menu router items that are local tasks for the passed-in path.
 *
 * @see contextual_links_preprocess()
 * @see hook_menu()
 */
function menu_contextual_links($module, $parent_path, $args) {
    static $path_empty = array();
    $links = array();
    // Performance: In case a previous invocation for the same parent path did not
    // return any links, we immediately return here.
    if (isset($path_empty[$parent_path]) && strpos($parent_path, '%') !== FALSE) {
        return $links;
    }
    // Construct the item-specific parent path.
    $path = $parent_path . '/' . implode('/', $args);
    // Get the router item for the given parent link path.
    $router_item = menu_get_item($path);
    if (!$router_item || !$router_item['access']) {
        $path_empty[$parent_path] = TRUE;
        return $links;
    }
    $data =& drupal_static(__FUNCTION__, array());
    $root_path = $router_item['path'];
    // Performance: For a single, normalized path (such as 'node/%') we only query
    // available tasks once per request.
    if (!isset($data[$root_path])) {
        // Get all contextual links that are direct children of the router item and
        // not of the tab type 'view'.
        $data[$root_path] = db_select('menu_router', 'm')->fields('m')
            ->condition('tab_parent', $router_item['tab_root'])
            ->condition('context', MENU_CONTEXT_NONE, '<>')
            ->condition('context', MENU_CONTEXT_PAGE, '<>')
            ->orderBy('weight')
            ->orderBy('title')
            ->execute()
            ->fetchAllAssoc('path', PDO::FETCH_ASSOC);
    }
    $parent_length = drupal_strlen($root_path) + 1;
    $map = $router_item['original_map'];
    foreach ($data[$root_path] as $item) {
        // Extract the actual "task" string from the path argument.
        $key = drupal_substr($item['path'], $parent_length);
        // Denormalize and translate the contextual link.
        _menu_translate($item, $map, TRUE);
        if (!$item['access']) {
            continue;
        }
        // All contextual links are keyed by the actual "task" path argument,
        // prefixed with the name of the implementing module.
        $links[$module . '-' . $key] = $item;
    }
    // Allow modules to alter contextual links.
    drupal_alter('menu_contextual_links', $links, $router_item, $root_path);
    // Performance: If the current user does not have access to any links for this
    // router path and no other module added further links, we assign FALSE here
    // to skip the entire process the next time the same router path is requested.
    if (empty($links)) {
        $path_empty[$parent_path] = TRUE;
    }
    return $links;
}

/**
 * Returns the rendered local tasks at the top level.
 */
function menu_primary_local_tasks() {
    $links = menu_local_tasks(0);
    // Do not display single tabs.
    return $links['tabs']['count'] > 1 ? $links['tabs']['output'] : '';
}

/**
 * Returns the rendered local tasks at the second level.
 */
function menu_secondary_local_tasks() {
    $links = menu_local_tasks(1);
    // Do not display single tabs.
    return $links['tabs']['count'] > 1 ? $links['tabs']['output'] : '';
}

/**
 * Returns the rendered local actions at the current level.
 */
function menu_local_actions() {
    $links = menu_local_tasks();
    return $links['actions']['output'];
}

/**
 * Returns the router path, or the path for a default local task's parent.
 */
function menu_tab_root_path() {
    $links = menu_local_tasks();
    return $links['root_path'];
}

/**
 * Returns a renderable element for the primary and secondary tabs.
 */
function menu_local_tabs() {
    return array(
        '#theme' => 'menu_local_tasks',
        '#primary' => menu_primary_local_tasks(),
        '#secondary' => menu_secondary_local_tasks(),
    );
}

/**
 * Returns HTML for primary and secondary local tasks.
 *
 * @param $variables
 *   An associative array containing:
 *     - primary: (optional) An array of local tasks (tabs).
 *     - secondary: (optional) An array of local tasks (tabs).
 *
 * @ingroup themeable
 * @see menu_local_tasks()
 */
function theme_menu_local_tasks(&$variables) {
    $output = '';
    if (!empty($variables['primary'])) {
        $variables['primary']['#prefix'] = '<h2 class="element-invisible">' . t('Primary tabs') . '</h2>';
        $variables['primary']['#prefix'] .= '<ul class="tabs primary">';
        $variables['primary']['#suffix'] = '</ul>';
        $output .= drupal_render($variables['primary']);
    }
    if (!empty($variables['secondary'])) {
        $variables['secondary']['#prefix'] = '<h2 class="element-invisible">' . t('Secondary tabs') . '</h2>';
        $variables['secondary']['#prefix'] .= '<ul class="tabs secondary">';
        $variables['secondary']['#suffix'] = '</ul>';
        $output .= drupal_render($variables['secondary']);
    }
    return $output;
}

/**
 * Sets (or gets) the active menu for the current page.
 *
 * The active menu for the page determines the active trail.
 *
 * @return
 *   An array of menu machine names, in order of preference. The
 *   'menu_default_active_menus' variable may be used to assert a menu order
 *   different from the order of creation, or to prevent a particular menu from
 *   being used at all in the active trail.
 *   E.g., $conf['menu_default_active_menus'] = array('navigation', 'main-menu')
 */
function menu_set_active_menu_names($menu_names = NULL) {
    $active =& drupal_static(__FUNCTION__);
    if (isset($menu_names) && is_array($menu_names)) {
        $active = $menu_names;
    }
    elseif (!isset($active)) {
        $active = variable_get('menu_default_active_menus', array_keys(menu_list_system_menus()));
    }
    return $active;
}

/**
 * Gets the active menu for the current page.
 */
function menu_get_active_menu_names() {
    return menu_set_active_menu_names();
}

/**
 * Sets the active path, which determines which page is loaded.
 *
 * Note that this may not have the desired effect unless invoked very early
 * in the page load, such as during hook_boot(), or unless you call
 * menu_execute_active_handler() to generate your page output.
 *
 * @param $path
 *   A Drupal path - not a path alias.
 */
function menu_set_active_item($path) {
    $_GET['q'] = $path;
    // Since the active item has changed, the active menu trail may also be out
    // of date.
    drupal_static_reset('menu_set_active_trail');
}

/**
 * Sets the active trail (path to the menu tree root) of the current page.
 *
 * Any trail set by this function will only be used for functionality that calls
 * menu_get_active_trail(). Drupal core only uses trails set here for
 * breadcrumbs and the page title and not for menu trees or page content.
 * Additionally, breadcrumbs set by drupal_set_breadcrumb() will override any
 * trail set here.
 *
 * To affect the trail used by menu trees, use menu_tree_set_path(). To affect
 * the page content, use menu_set_active_item() instead.
 *
 * @param $new_trail
 *   Menu trail to set; the value is saved in a static variable and can be
 *   retrieved by menu_get_active_trail(). The format of this array should be
 *   the same as the return value of menu_get_active_trail().
 *
 * @return
 *   The active trail. See menu_get_active_trail() for details.
 */
function menu_set_active_trail($new_trail = NULL) {
    $trail =& drupal_static(__FUNCTION__);
    if (isset($new_trail)) {
        $trail = $new_trail;
    }
    elseif (!isset($trail)) {
        $trail = array();
        $trail[] = array(
            'title' => t('Home'),
            'href' => '<front>',
            'link_path' => '',
            'localized_options' => array(),
            'type' => 0,
        );
        // Try to retrieve a menu link corresponding to the current path. If more
        // than one exists, the link from the most preferred menu is returned.
        $preferred_link = menu_link_get_preferred();
        $current_item = menu_get_item();
        // There is a link for the current path.
        if ($preferred_link) {
            // Pass TRUE for $only_active_trail to make menu_tree_page_data() build
            // a stripped down menu tree containing the active trail only, in case
            // the given menu has not been built in this request yet.
            $tree = menu_tree_page_data($preferred_link['menu_name'], NULL, TRUE);
            $curr = current($tree);
            next($tree);
        }
        else {
            $preferred_link = $current_item;
            $curr = FALSE;
        }
        while ($curr) {
            $link = $curr['link'];
            if ($link['in_active_trail']) {
                // Add the link to the trail, unless it links to its parent.
                if (!($link['type'] & MENU_LINKS_TO_PARENT)) {
                    // The menu tree for the active trail may contain additional links
                    // that have not been translated yet, since they contain dynamic
                    // argument placeholders (%). Such links are not contained in regular
                    // menu trees, and have only been loaded for the additional
                    // translation that happens here, so as to be able to display them in
                    // the breadcrumb for the current page.
                    // @see _menu_tree_check_access()
                    // @see _menu_link_translate()
                    if (strpos($link['href'], '%') !== FALSE) {
                        _menu_link_translate($link, TRUE);
                    }
                    if ($link['access']) {
                        $trail[] = $link;
                    }
                }
                $tree = $curr['below'] ? $curr['below'] : array();
            }
            $curr = current($tree);
            next($tree);
        }
        // Make sure the current page is in the trail to build the page title, by
        // appending either the preferred link or the menu router item for the
        // current page. Exclude it if we are on the front page.
        $last = end($trail);
        if ($preferred_link && $last['href'] != $preferred_link['href'] && !drupal_is_front_page()) {
            $trail[] = $preferred_link;
        }
    }
    return $trail;
}

/**
 * Looks up the preferred menu link for a given system path.
 *
 * @param $path
 *   The path; for example, 'node/5'. The function will find the corresponding
 *   menu link ('node/5' if it exists, or fallback to 'node/%').
 * @param $selected_menu
 *   The name of a menu used to restrict the search for a preferred menu link.
 *   If not specified, all the menus returned by menu_get_active_menu_names()
 *   will be used.
 *
 * @return
 *   A fully translated menu link, or FALSE if no matching menu link was
 *   found. The most specific menu link ('node/5' preferred over 'node/%') in
 *   the most preferred menu (as defined by menu_get_active_menu_names()) is
 *   returned.
 */
function menu_link_get_preferred($path = NULL, $selected_menu = NULL) {
    $preferred_links =& drupal_static(__FUNCTION__);
    if (!isset($path)) {
        $path = $_GET['q'];
    }
    if (empty($selected_menu)) {
        // Use an illegal menu name as the key for the preferred menu link.
        $selected_menu = MENU_PREFERRED_LINK;
    }
    if (!isset($preferred_links[$path])) {
        // Look for the correct menu link by building a list of candidate paths,
        // which are ordered by priority (translated hrefs are preferred over
        // untranslated paths). Afterwards, the most relevant path is picked from
        // the menus, ordered by menu preference.
        $item = menu_get_item($path);
        if ($item === FALSE) {
            return FALSE;
        }
        $path_candidates = array();
        // 1. The current item href.
        $path_candidates[$item['href']] = $item['href'];
        // 2. The tab root href of the current item (if any).
        if ($item['tab_parent'] && ($tab_root = menu_get_item($item['tab_root_href']))) {
            $path_candidates[$tab_root['href']] = $tab_root['href'];
        }
        // 3. The current item path (with wildcards).
        $path_candidates[$item['path']] = $item['path'];
        // 4. The tab root path of the current item (if any).
        if (!empty($tab_root)) {
            $path_candidates[$tab_root['path']] = $tab_root['path'];
        }
        // Retrieve a list of menu names, ordered by preference.
        $menu_names = menu_get_active_menu_names();
        // Put the selected menu at the front of the list.
        array_unshift($menu_names, $selected_menu);
        $query = db_select('menu_links', 'ml', array(
            'fetch' => PDO::FETCH_ASSOC,
        ));
        $query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
        $query->fields('ml');
        // Weight must be taken from {menu_links}, not {menu_router}.
        $query->addField('ml', 'weight', 'link_weight');
        $query->fields('m');
        $query->condition('ml.link_path', $path_candidates, 'IN');
        $query->addTag('preferred_menu_links');
        // Sort candidates by link path and menu name.
        $candidates = array();
        foreach ($query->execute() as $candidate) {
            $candidate['weight'] = $candidate['link_weight'];
            $candidates[$candidate['link_path']][$candidate['menu_name']] = $candidate;
            // Add any menus not already in the menu name search list.
            if (!in_array($candidate['menu_name'], $menu_names)) {
                $menu_names[] = $candidate['menu_name'];
            }
        }
        // Store the most specific link for each menu. Also save the most specific
        // link of the most preferred menu in $preferred_link.
        foreach ($path_candidates as $link_path) {
            if (isset($candidates[$link_path])) {
                foreach ($menu_names as $menu_name) {
                    if (empty($preferred_links[$path][$menu_name]) && isset($candidates[$link_path][$menu_name])) {
                        $candidate_item = $candidates[$link_path][$menu_name];
                        $map = explode('/', $path);
                        _menu_translate($candidate_item, $map);
                        if ($candidate_item['access']) {
                            $preferred_links[$path][$menu_name] = $candidate_item;
                            if (empty($preferred_links[$path][MENU_PREFERRED_LINK])) {
                                // Store the most specific link.
                                $preferred_links[$path][MENU_PREFERRED_LINK] = $candidate_item;
                            }
                        }
                    }
                }
            }
        }
    }
    return isset($preferred_links[$path][$selected_menu]) ? $preferred_links[$path][$selected_menu] : FALSE;
}

/**
 * Gets the active trail (path to root menu root) of the current page.
 *
 * If a trail is supplied to menu_set_active_trail(), that value is returned. If
 * a trail is not supplied to menu_set_active_trail(), the path to the current
 * page is calculated and returned. The calculated trail is also saved as a
 * static value for use by subsequent calls to menu_get_active_trail().
 *
 * @return
 *   Path to menu root of the current page, as an array of menu link items,
 *   starting with the site's home page. Each link item is an associative array
 *   with the following components:
 *   - title: Title of the item.
 *   - href: Drupal path of the item.
 *   - localized_options: Options for passing into the l() function.
 *   - type: A menu type constant, such as MENU_DEFAULT_LOCAL_TASK, or 0 to
 *     indicate it's not really in the menu (used for the home page item).
 */
function menu_get_active_trail() {
    return menu_set_active_trail();
}

/**
 * Gets the breadcrumb for the current page, as determined by the active trail.
 *
 * @see menu_set_active_trail()
 */
function menu_get_active_breadcrumb() {
    $breadcrumb = array();
    // No breadcrumb for the front page.
    if (drupal_is_front_page()) {
        return $breadcrumb;
    }
    $item = menu_get_item();
    if (!empty($item['access'])) {
        $active_trail = menu_get_active_trail();
        // Allow modules to alter the breadcrumb, if possible, as that is much
        // faster than rebuilding an entirely new active trail.
        drupal_alter('menu_breadcrumb', $active_trail, $item);
        // Don't show a link to the current page in the breadcrumb trail.
        $end = end($active_trail);
        if (is_array($end) && $item['href'] == $end['href']) {
            array_pop($active_trail);
        }
        // Remove the tab root (parent) if the current path links to its parent.
        // Normally, the tab root link is included in the breadcrumb, as soon as we
        // are on a local task or any other child link. However, if we are on a
        // default local task (e.g., node/%/view), then we do not want the tab root
        // link (e.g., node/%) to appear, as it would be identical to the current
        // page. Since this behavior also needs to work recursively (i.e., on
        // default local tasks of default local tasks), and since the last non-task
        // link in the trail is used as page title (see menu_get_active_title()),
        // this condition cannot be cleanly integrated into menu_get_active_trail().
        // menu_get_active_trail() already skips all links that link to their parent
        // (commonly MENU_DEFAULT_LOCAL_TASK). In order to also hide the parent link
        // itself, we always remove the last link in the trail, if the current
        // router item links to its parent.
        if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
            array_pop($active_trail);
        }
        foreach ($active_trail as $parent) {
            $breadcrumb[] = l($parent['title'], $parent['href'], $parent['localized_options']);
        }
    }
    return $breadcrumb;
}

/**
 * Gets the title of the current page, as determined by the active trail.
 */
function menu_get_active_title() {
    $active_trail = menu_get_active_trail();
    $local_task_title = NULL;
    foreach (array_reverse($active_trail) as $item) {
        // Local task titles are displayed as tabs and therefore should not be
        // repeated as the page title. However, if the local task appears in a
        // top-level menu, it is no longer a "local task" anymore (the front page
        // of the site does not have tabs) so it is better to use the local task
        // title in that case than to fall back on the front page link in the
        // active trail (which is usually "Home" and would not make sense in this
        // context).
        if ((bool) ($item['type'] & MENU_IS_LOCAL_TASK)) {
            // A local task title is being skipped; track it in case it needs to be
            // used later.
            $local_task_title = $item['title'];
        }
        else {
            // This is not a local task, so use it for the page title (unless the
            // conditions described above are met).
            if (isset($local_task_title) && isset($item['href']) && $item['href'] == '<front>') {
                return $local_task_title;
            }
            else {
                return $item['title'];
            }
        }
    }
}

/**
 * Gets a translated, access-checked menu link that is ready for rendering.
 *
 * This function should never be called from within node_load() or any other
 * function used as a menu object load function since an infinite recursion may
 * occur.
 *
 * @param $mlid
 *   The mlid of the menu item.
 *
 * @return
 *   A menu link, with $item['access'] filled and link translated for
 *   rendering.
 */
function menu_link_load($mlid) {
    if (is_numeric($mlid)) {
        $query = db_select('menu_links', 'ml');
        $query->leftJoin('menu_router', 'm', 'm.path = ml.router_path');
        $query->fields('ml');
        // Weight should be taken from {menu_links}, not {menu_router}.
        $query->addField('ml', 'weight', 'link_weight');
        $query->fields('m');
        $query->condition('ml.mlid', $mlid);
        if ($item = $query->execute()
            ->fetchAssoc()) {
            $item['weight'] = $item['link_weight'];
            _menu_link_translate($item);
            return $item;
        }
    }
    return FALSE;
}

/**
 * Clears the cached data for a single named menu.
 */
function menu_cache_clear($menu_name = 'navigation') {
    $cache_cleared =& drupal_static(__FUNCTION__, array());
    if (empty($cache_cleared[$menu_name])) {
        cache_clear_all('links:' . $menu_name . ':', 'cache_menu', TRUE);
        $cache_cleared[$menu_name] = 1;
    }
    elseif ($cache_cleared[$menu_name] == 1) {
        drupal_register_shutdown_function('cache_clear_all', 'links:' . $menu_name . ':', 'cache_menu', TRUE);
        $cache_cleared[$menu_name] = 2;
    }
    // Also clear the menu system static caches.
    menu_reset_static_cache();
}

/**
 * Clears all cached menu data.
 *
 * This should be called any time broad changes
 * might have been made to the router items or menu links.
 */
function menu_cache_clear_all() {
    cache_clear_all('*', 'cache_menu', TRUE);
    menu_reset_static_cache();
}

/**
 * Resets the menu system static cache.
 */
function menu_reset_static_cache() {
    drupal_static_reset('_menu_build_tree');
    drupal_static_reset('menu_tree');
    drupal_static_reset('menu_tree_all_data');
    drupal_static_reset('menu_tree_page_data');
    drupal_static_reset('menu_load_all');
    drupal_static_reset('menu_link_get_preferred');
}

/**
 * Checks whether a menu_rebuild() is necessary.
 */
function _menu_check_rebuild() {
    // To absolutely ensure that the menu rebuild is required, re-load the
    // variables in case they were set by another process.
    $variables = variable_initialize();
    if (empty($variables['menu_rebuild_needed']) && !empty($variables['menu_masks'])) {
        unset($GLOBALS['conf']['menu_rebuild_needed']);
        $GLOBALS['conf']['menu_masks'] = $variables['menu_masks'];
        return FALSE;
    }
    return TRUE;
}

/**
 * Populates the database tables used by various menu functions.
 *
 * This function will clear and populate the {menu_router} table, add entries
 * to {menu_links} for new router items, and then remove stale items from
 * {menu_links}. If called from update.php or install.php, it will also
 * schedule a call to itself on the first real page load from
 * menu_execute_active_handler(), because the maintenance page environment
 * is different and leaves stale data in the menu tables.
 *
 * @return
 *   TRUE if the menu was rebuilt, FALSE if another thread was rebuilding
 *   in parallel and the current thread just waited for completion.
 */
function menu_rebuild() {
    if (!lock_acquire('menu_rebuild')) {
        // Wait for another request that is already doing this work.
        // We choose to block here since otherwise the router item may not
        // be available in menu_execute_active_handler() resulting in a 404.
        lock_wait('menu_rebuild');
        if (_menu_check_rebuild()) {
            // If we get here and menu_masks was not set, then it is possible a menu
            // is being reloaded, or that the process rebuilding the menu was unable
            // to complete successfully. A missing menu_masks variable could result
            // in a 404, so re-run the function.
            return menu_rebuild();
        }
        return FALSE;
    }
    $transaction = db_transaction();
    try {
        list($menu, $masks) = menu_router_build();
        _menu_router_save($menu, $masks);
        _menu_navigation_links_rebuild($menu);
        // Clear the menu, page and block caches.
        menu_cache_clear_all();
        _menu_clear_page_cache();
        if (defined('MAINTENANCE_MODE')) {
            variable_set('menu_rebuild_needed', TRUE);
        }
        else {
            variable_del('menu_rebuild_needed');
        }
    } catch (Exception $e) {
        $transaction->rollback();
        watchdog_exception('menu', $e);
    }
    // Explicitly commit the transaction now; this ensures that the database
    // operations during the menu rebuild are committed before the lock is made
    // available again, since locks may not always reside in the same database
    // connection. The lock is acquired outside of the transaction so should also
    // be released outside of it.
    unset($transaction);
    lock_release('menu_rebuild');
    return TRUE;
}

/**
 * Collects and alters the menu definitions.
 */
function menu_router_build() {
    // We need to manually call each module so that we can know which module
    // a given item came from.
    $callbacks = array();
    foreach (module_implements('menu') as $module) {
        $router_items = call_user_func($module . '_menu');
        if (isset($router_items) && is_array($router_items)) {
            foreach (array_keys($router_items) as $path) {
                $router_items[$path]['module'] = $module;
            }
            $callbacks = array_merge($callbacks, $router_items);
        }
    }
    // Alter the menu as defined in modules, keys are like user/%user.
    drupal_alter('menu', $callbacks);
    list($menu, $masks) = _menu_router_build($callbacks);
    _menu_router_cache($menu);
    return array(
        $menu,
        $masks,
    );
}

/**
 * Stores the menu router if we have it in memory.
 */
function _menu_router_cache($new_menu = NULL) {
    $menu =& drupal_static(__FUNCTION__);
    if (isset($new_menu)) {
        $menu = $new_menu;
    }
    return $menu;
}

/**
 * Gets the menu router.
 */
function menu_get_router() {
    // Check first if we have it in memory already.
    $menu = _menu_router_cache();
    if (empty($menu)) {
        list($menu, $masks) = menu_router_build();
    }
    return $menu;
}

/**
 * Builds a link from a router item.
 */
function _menu_link_build($item) {
    // Suggested items are disabled by default.
    if ($item['type'] == MENU_SUGGESTED_ITEM) {
        $item['hidden'] = 1;
    }
    elseif (!($item['type'] & MENU_VISIBLE_IN_TREE)) {
        $item['hidden'] = -1;
    }
    // Note, we set this as 'system', so that we can be sure to distinguish all
    // the menu links generated automatically from entries in {menu_router}.
    $item['module'] = 'system';
    $item += array(
        'menu_name' => 'navigation',
        'link_title' => $item['title'],
        'link_path' => $item['path'],
        'hidden' => 0,
        'options' => empty($item['description']) ? array() : array(
            'attributes' => array(
                'title' => $item['description'],
            ),
        ),
    );
    return $item;
}

/**
 * Builds menu links for the items in the menu router.
 */
function _menu_navigation_links_rebuild($menu) {
    // Add normal and suggested items as links.
    $menu_links = array();
    foreach ($menu as $path => $item) {
        if ($item['_visible']) {
            $menu_links[$path] = $item;
            $sort[$path] = $item['_number_parts'];
        }
    }
    if ($menu_links) {
        // Keep an array of processed menu links, to allow menu_link_save() to
        // check this for parents instead of querying the database.
        $parent_candidates = array();
        // Make sure no child comes before its parent.
        array_multisort($sort, SORT_NUMERIC, $menu_links);
        foreach ($menu_links as $key => $item) {
            $existing_item = db_select('menu_links')->fields('menu_links')
                ->condition('link_path', $item['path'])
                ->condition('module', 'system')
                ->execute()
                ->fetchAssoc();
            if ($existing_item) {
                $item['mlid'] = $existing_item['mlid'];
                // A change in hook_menu may move the link to a different menu
                if (empty($item['menu_name']) || $item['menu_name'] == $existing_item['menu_name']) {
                    $item['menu_name'] = $existing_item['menu_name'];
                    $item['plid'] = $existing_item['plid'];
                }
                else {
                    // It moved to a new menu. Let menu_link_save() try to find a new
                    // parent based on the path.
                    unset($item['plid']);
                }
                $item['has_children'] = $existing_item['has_children'];
                $item['updated'] = $existing_item['updated'];
            }
            if ($existing_item && $existing_item['customized']) {
                $parent_candidates[$existing_item['mlid']] = $existing_item;
            }
            else {
                $item = _menu_link_build($item);
                menu_link_save($item, $existing_item, $parent_candidates);
                $parent_candidates[$item['mlid']] = $item;
                unset($menu_links[$key]);
            }
        }
    }
    $paths = array_keys($menu);
    // Updated and customized items whose router paths are gone need new ones.
    $result = db_select('menu_links', NULL, array(
        'fetch' => PDO::FETCH_ASSOC,
    ))->fields('menu_links', array(
        'link_path',
        'mlid',
        'router_path',
        'updated',
    ))
        ->condition(db_or()->condition('updated', 1)
        ->condition(db_and()->condition('router_path', $paths, 'NOT IN')
        ->condition('external', 0)
        ->condition('customized', 1)))
        ->execute();
    foreach ($result as $item) {
        $router_path = _menu_find_router_path($item['link_path']);
        if (!empty($router_path) && ($router_path != $item['router_path'] || $item['updated'])) {
            // If the router path and the link path matches, it's surely a working
            // item, so we clear the updated flag.
            $updated = $item['updated'] && $router_path != $item['link_path'];
            db_update('menu_links')->fields(array(
                'router_path' => $router_path,
                'updated' => (int) $updated,
            ))
                ->condition('mlid', $item['mlid'])
                ->execute();
        }
    }
    // Find any item whose router path does not exist any more.
    $result = db_select('menu_links')->fields('menu_links')
        ->condition('router_path', $paths, 'NOT IN')
        ->condition('external', 0)
        ->condition('updated', 0)
        ->condition('customized', 0)
        ->orderBy('depth', 'DESC')
        ->execute();
    // Remove all such items. Starting from those with the greatest depth will
    // minimize the amount of re-parenting done by menu_link_delete().
    foreach ($result as $item) {
        _menu_delete_item($item, TRUE);
    }
}

/**
 * Clones an array of menu links.
 *
 * @param $links
 *   An array of menu links to clone.
 * @param $menu_name
 *   (optional) The name of a menu that the links will be cloned for. If not
 *   set, the cloned links will be in the same menu as the original set of
 *   links that were passed in.
 *
 * @return
 *   An array of menu links with the same properties as the passed-in array,
 *   but with the link identifiers removed so that a new link will be created
 *   when any of them is passed in to menu_link_save().
 *
 * @see menu_link_save()
 */
function menu_links_clone($links, $menu_name = NULL) {
    foreach ($links as &$link) {
        unset($link['mlid']);
        unset($link['plid']);
        if (isset($menu_name)) {
            $link['menu_name'] = $menu_name;
        }
    }
    return $links;
}

/**
 * Returns an array containing all links for a menu.
 *
 * @param $menu_name
 *   The name of the menu whose links should be returned.
 *
 * @return
 *   An array of menu links.
 */
function menu_load_links($menu_name) {
    $links = db_select('menu_links', 'ml', array(
        'fetch' => PDO::FETCH_ASSOC,
    ))->fields('ml')
        ->condition('ml.menu_name', $menu_name)
        ->orderBy('weight')
        ->execute()
        ->fetchAll();
    foreach ($links as &$link) {
        $link['options'] = unserialize($link['options']);
    }
    return $links;
}

/**
 * Deletes all links for a menu.
 *
 * @param $menu_name
 *   The name of the menu whose links will be deleted.
 */
function menu_delete_links($menu_name) {
    $links = menu_load_links($menu_name);
    foreach ($links as $link) {
        // To speed up the deletion process, we reset some link properties that
        // would trigger re-parenting logic in _menu_delete_item() and
        // _menu_update_parental_status().
        $link['has_children'] = FALSE;
        $link['plid'] = 0;
        _menu_delete_item($link);
    }
}

/**
 * Delete one or several menu links.
 *
 * @param $mlid
 *   A valid menu link mlid or NULL. If NULL, $path is used.
 * @param $path
 *   The path to the menu items to be deleted. $mlid must be NULL.
 */
function menu_link_delete($mlid, $path = NULL) {
    if (isset($mlid)) {
        _menu_delete_item(db_query("SELECT * FROM {menu_links} WHERE mlid = :mlid", array(
            ':mlid' => $mlid,
        ))->fetchAssoc());
    }
    else {
        $result = db_query("SELECT * FROM {menu_links} WHERE link_path = :link_path", array(
            ':link_path' => $path,
        ));
        foreach ($result as $link) {
            _menu_delete_item($link);
        }
    }
}

/**
 * Deletes a single menu link.
 *
 * @param $item
 *   Item to be deleted.
 * @param $force
 *   Forces deletion. Internal use only, setting to TRUE is discouraged.
 *
 * @see menu_link_delete()
 */
function _menu_delete_item($item, $force = FALSE) {
    $item = is_object($item) ? get_object_vars($item) : $item;
    if ($item && ($item['module'] != 'system' || $item['updated'] || $force)) {
        // Children get re-attached to the item's parent.
        if ($item['has_children']) {
            $result = db_query("SELECT mlid FROM {menu_links} WHERE plid = :plid", array(
                ':plid' => $item['mlid'],
            ));
            foreach ($result as $m) {
                $child = menu_link_load($m->mlid);
                $child['plid'] = $item['plid'];
                menu_link_save($child);
            }
        }
        // Notify modules we are deleting the item.
        module_invoke_all('menu_link_delete', $item);
        db_delete('menu_links')->condition('mlid', $item['mlid'])
            ->execute();
        // Update the has_children status of the parent.
        _menu_update_parental_status($item);
        menu_cache_clear($item['menu_name']);
        _menu_clear_page_cache();
    }
}

/**
 * Saves a menu link.
 *
 * After calling this function, rebuild the menu cache using
 * menu_cache_clear_all().
 *
 * @param $item
 *   An associative array representing a menu link item, with elements:
 *   - link_path: (required) The path of the menu item, which should be
 *     normalized first by calling drupal_get_normal_path() on it.
 *   - link_title: (required) Title to appear in menu for the link.
 *   - menu_name: (optional) The machine name of the menu for the link.
 *     Defaults to 'navigation'.
 *   - weight: (optional) Integer to determine position in menu. Default is 0.
 *   - expanded: (optional) Boolean that determines if the item is expanded.
 *   - options: (optional) An array of options, see l() for more.
 *   - mlid: (optional) Menu link identifier, the primary integer key for each
 *     menu link. Can be set to an existing value, or to 0 or NULL
 *     to insert a new link.
 *   - plid: (optional) The mlid of the parent.
 *   - router_path: (optional) The path of the relevant router item.
 * @param $existing_item
 *   Optional, the current record from the {menu_links} table as an array.
 * @param $parent_candidates
 *   Optional array of menu links keyed by mlid. Used by
 *   _menu_navigation_links_rebuild() only.
 *
 * @return
 *   The mlid of the saved menu link, or FALSE if the menu link could not be
 *   saved.
 */
function menu_link_save(&$item, $existing_item = array(), $parent_candidates = array()) {
    drupal_alter('menu_link', $item);
    // This is the easiest way to handle the unique internal path '<front>',
    // since a path marked as external does not need to match a router path.
    $item['external'] = url_is_external($item['link_path']) || $item['link_path'] == '<front>' ? 1 : 0;
    // Load defaults.
    $item += array(
        'menu_name' => 'navigation',
        'weight' => 0,
        'link_title' => '',
        'hidden' => 0,
        'has_children' => 0,
        'expanded' => 0,
        'options' => array(),
        'module' => 'menu',
        'customized' => 0,
        'updated' => 0,
    );
    if (isset($item['mlid'])) {
        if (!$existing_item) {
            $existing_item = db_query('SELECT * FROM {menu_links} WHERE mlid = :mlid', array(
                'mlid' => $item['mlid'],
            ))->fetchAssoc();
        }
        if ($existing_item) {
            $existing_item['options'] = unserialize($existing_item['options']);
        }
    }
    else {
        $existing_item = FALSE;
    }
    // Try to find a parent link. If found, assign it and derive its menu.
    $parent = _menu_link_find_parent($item, $parent_candidates);
    if (!empty($parent['mlid'])) {
        $item['plid'] = $parent['mlid'];
        $item['menu_name'] = $parent['menu_name'];
    }
    else {
        $item['plid'] = 0;
    }
    $menu_name = $item['menu_name'];
    if (!$existing_item) {
        $item['mlid'] = db_insert('menu_links')->fields(array(
            'menu_name' => $item['menu_name'],
            'plid' => $item['plid'],
            'link_path' => $item['link_path'],
            'hidden' => $item['hidden'],
            'external' => $item['external'],
            'has_children' => $item['has_children'],
            'expanded' => $item['expanded'],
            'weight' => (int) $item['weight'],
            'module' => $item['module'],
            'link_title' => $item['link_title'],
            'options' => serialize($item['options']),
            'customized' => $item['customized'],
            'updated' => $item['updated'],
        ))
            ->execute();
    }
    // Directly fill parents for top-level links.
    if ($item['plid'] == 0) {
        $item['p1'] = $item['mlid'];
        for ($i = 2; $i <= MENU_MAX_DEPTH; $i++) {
            $item["p{$i}"] = 0;
        }
        $item['depth'] = 1;
    }
    else {
        if ($item['has_children'] && $existing_item) {
            $limit = MENU_MAX_DEPTH - menu_link_children_relative_depth($existing_item) - 1;
        }
        else {
            $limit = MENU_MAX_DEPTH - 1;
        }
        if ($parent['depth'] > $limit) {
            return FALSE;
        }
        $item['depth'] = $parent['depth'] + 1;
        _menu_link_parents_set($item, $parent);
    }
    // Need to check both plid and menu_name, since plid can be 0 in any menu.
    if ($existing_item && ($item['plid'] != $existing_item['plid'] || $menu_name != $existing_item['menu_name'])) {
        _menu_link_move_children($item, $existing_item);
    }
    // Find the router_path.
    if (empty($item['router_path']) || !$existing_item || $existing_item['link_path'] != $item['link_path']) {
        if ($item['external']) {
            $item['router_path'] = '';
        }
        else {
            // Find the router path which will serve this path.
            $item['parts'] = explode('/', $item['link_path'], MENU_MAX_PARTS);
            $item['router_path'] = _menu_find_router_path($item['link_path']);
        }
    }
    // If every value in $existing_item is the same in the $item, there is no
    // reason to run the update queries or clear the caches. We use
    // array_intersect_key() with the $item as the first parameter because
    // $item may have additional keys left over from building a router entry.
    // The intersect removes the extra keys, allowing a meaningful comparison.
    if (!$existing_item || array_intersect_key($item, $existing_item) != $existing_item) {
        db_update('menu_links')->fields(array(
            'menu_name' => $item['menu_name'],
            'plid' => $item['plid'],
            'link_path' => $item['link_path'],
            'router_path' => $item['router_path'],
            'hidden' => $item['hidden'],
            'external' => $item['external'],
            'has_children' => $item['has_children'],
            'expanded' => $item['expanded'],
            'weight' => (int) $item['weight'],
            'depth' => $item['depth'],
            'p1' => $item['p1'],
            'p2' => $item['p2'],
            'p3' => $item['p3'],
            'p4' => $item['p4'],
            'p5' => $item['p5'],
            'p6' => $item['p6'],
            'p7' => $item['p7'],
            'p8' => $item['p8'],
            'p9' => $item['p9'],
            'module' => $item['module'],
            'link_title' => $item['link_title'],
            'options' => serialize($item['options']),
            'customized' => $item['customized'],
        ))
            ->condition('mlid', $item['mlid'])
            ->execute();
        // Check the has_children status of the parent.
        _menu_update_parental_status($item);
        menu_cache_clear($menu_name);
        if ($existing_item && $menu_name != $existing_item['menu_name']) {
            menu_cache_clear($existing_item['menu_name']);
        }
        // Notify modules we have acted on a menu item.
        $hook = 'menu_link_insert';
        if ($existing_item) {
            $hook = 'menu_link_update';
        }
        module_invoke_all($hook, $item);
        // Now clear the cache.
        _menu_clear_page_cache();
    }
    return $item['mlid'];
}

/**
 * Finds a possible parent for a given menu link.
 *
 * Because the parent of a given link might not exist anymore in the database,
 * we apply a set of heuristics to determine a proper parent:
 *
 *  - use the passed parent link if specified and existing.
 *  - else, use the first existing link down the previous link hierarchy
 *  - else, for system menu links (derived from hook_menu()), reparent
 *    based on the path hierarchy.
 *
 * @param $menu_link
 *   A menu link.
 * @param $parent_candidates
 *   An array of menu links keyed by mlid.
 *
 * @return
 *   A menu link structure of the possible parent or FALSE if no valid parent
 *   has been found.
 */
function _menu_link_find_parent($menu_link, $parent_candidates = array()) {
    $parent = FALSE;
    // This item is explicitely top-level, skip the rest of the parenting.
    if (isset($menu_link['plid']) && empty($menu_link['plid'])) {
        return $parent;
    }
    // If we have a parent link ID, try to use that.
    $candidates = array();
    if (isset($menu_link['plid'])) {
        $candidates[] = $menu_link['plid'];
    }
    // Else, if we have a link hierarchy try to find a valid parent in there.
    if (!empty($menu_link['depth']) && $menu_link['depth'] > 1) {
        for ($depth = $menu_link['depth'] - 1; $depth >= 1; $depth--) {
            $candidates[] = $menu_link['p' . $depth];
        }
    }
    foreach ($candidates as $mlid) {
        if (isset($parent_candidates[$mlid])) {
            $parent = $parent_candidates[$mlid];
        }
        else {
            $parent = db_query("SELECT * FROM {menu_links} WHERE mlid = :mlid", array(
                ':mlid' => $mlid,
            ))->fetchAssoc();
        }
        if ($parent) {
            return $parent;
        }
    }
    // If everything else failed, try to derive the parent from the path
    // hierarchy. This only makes sense for links derived from menu router
    // items (ie. from hook_menu()).
    if ($menu_link['module'] == 'system') {
        $query = db_select('menu_links');
        $query->condition('module', 'system');
        // We always respect the link's 'menu_name'; inheritance for router items is
        // ensured in _menu_router_build().
        $query->condition('menu_name', $menu_link['menu_name']);
        // Find the parent - it must be unique.
        $parent_path = $menu_link['link_path'];
        do {
            $parent = FALSE;
            $parent_path = substr($parent_path, 0, strrpos($parent_path, '/'));
            $new_query = clone $query;
            $new_query->condition('link_path', $parent_path);
            // Only valid if we get a unique result.
            if ($new_query->countQuery()
                ->execute()
                ->fetchField() == 1) {
                $parent = $new_query->fields('menu_links')
                    ->execute()
                    ->fetchAssoc();
            }
        } while ($parent === FALSE && $parent_path);
    }
    return $parent;
}

/**
 * Clears the page and block caches at most twice per page load.
 */
function _menu_clear_page_cache() {
    $cache_cleared =& drupal_static(__FUNCTION__, 0);
    // Clear the page and block caches, but at most twice, including at
    //  the end of the page load when there are multiple links saved or deleted.
    if ($cache_cleared == 0) {
        cache_clear_all();
        // Keep track of which menus have expanded items.
        _menu_set_expanded_menus();
        $cache_cleared = 1;
    }
    elseif ($cache_cleared == 1) {
        drupal_register_shutdown_function('cache_clear_all');
        // Keep track of which menus have expanded items.
        drupal_register_shutdown_function('_menu_set_expanded_menus');
        $cache_cleared = 2;
    }
}

/**
 * Updates a list of menus with expanded items.
 */
function _menu_set_expanded_menus() {
    $names = db_query("SELECT menu_name FROM {menu_links} WHERE expanded <> 0 GROUP BY menu_name")->fetchCol();
    variable_set('menu_expanded', $names);
}

/**
 * Finds the router path which will serve this path.
 *
 * @param $link_path
 *  The path for we are looking up its router path.
 *
 * @return
 *  A path from $menu keys or empty if $link_path points to a nonexisting
 *  place.
 */
function _menu_find_router_path($link_path) {
    // $menu will only have data during a menu rebuild.
    $menu = _menu_router_cache();
    $router_path = $link_path;
    $parts = explode('/', $link_path, MENU_MAX_PARTS);
    $ancestors = menu_get_ancestors($parts);
    if (empty($menu)) {
        // Not during a menu rebuild, so look up in the database.
        $router_path = (string) db_select('menu_router')->fields('menu_router', array(
            'path',
        ))
            ->condition('path', $ancestors, 'IN')
            ->orderBy('fit', 'DESC')
            ->range(0, 1)
            ->execute()
            ->fetchField();
    }
    elseif (!isset($menu[$router_path])) {
        // Add an empty router path as a fallback.
        $ancestors[] = '';
        foreach ($ancestors as $key => $router_path) {
            if (isset($menu[$router_path])) {
                // Exit the loop leaving $router_path as the first match.
                break;
            }
        }
        // If we did not find the path, $router_path will be the empty string
        // at the end of $ancestors.
    }
    return $router_path;
}

/**
 * Inserts, updates, or deletes an uncustomized menu link related to a module.
 *
 * @param $module
 *   The name of the module.
 * @param $op
 *   Operation to perform: insert, update or delete.
 * @param $link_path
 *   The path this link points to.
 * @param $link_title
 *   Title of the link to insert or new title to update the link to.
 *   Unused for delete.
 *
 * @return
 *   The insert op returns the mlid of the new item. Others op return NULL.
 */
function menu_link_maintain($module, $op, $link_path, $link_title) {
    switch ($op) {
        case 'insert':
            $menu_link = array(
                'link_title' => $link_title,
                'link_path' => $link_path,
                'module' => $module,
            );
            return menu_link_save($menu_link);
            break;
        case 'update':
            $result = db_query("SELECT * FROM {menu_links} WHERE link_path = :link_path AND module = :module AND customized = 0", array(
                ':link_path' => $link_path,
                ':module' => $module,
            ))->fetchAll(PDO::FETCH_ASSOC);
            foreach ($result as $link) {
                $link['link_title'] = $link_title;
                $link['options'] = unserialize($link['options']);
                menu_link_save($link);
            }
            break;
        case 'delete':
            menu_link_delete(NULL, $link_path);
            break;
    }
}

/**
 * Finds the depth of an item's children relative to its depth.
 *
 * For example, if the item has a depth of 2, and the maximum of any child in
 * the menu link tree is 5, the relative depth is 3.
 *
 * @param $item
 *   An array representing a menu link item.
 *
 * @return
 *   The relative depth, or zero.
 *
 */
function menu_link_children_relative_depth($item) {
    $query = db_select('menu_links');
    $query->addField('menu_links', 'depth');
    $query->condition('menu_name', $item['menu_name']);
    $query->orderBy('depth', 'DESC');
    $query->range(0, 1);
    $i = 1;
    $p = 'p1';
    while ($i <= MENU_MAX_DEPTH && $item[$p]) {
        $query->condition($p, $item[$p]);
        $p = 'p' . ++$i;
    }
    $max_depth = $query->execute()
        ->fetchField();
    return $max_depth > $item['depth'] ? $max_depth - $item['depth'] : 0;
}

/**
 * Updates the children of a menu link that is being moved.
 *
 * The menu name, parents (p1 - p6), and depth are updated for all children of
 * the link, and the has_children status of the previous parent is updated.
 */
function _menu_link_move_children($item, $existing_item) {
    $query = db_update('menu_links');
    $query->fields(array(
        'menu_name' => $item['menu_name'],
    ));
    $p = 'p1';
    $expressions = array();
    for ($i = 1; $i <= $item['depth']; $p = 'p' . ++$i) {
        $expressions[] = array(
            $p,
            ":p_{$i}",
            array(
                ":p_{$i}" => $item[$p],
            ),
        );
    }
    $j = $existing_item['depth'] + 1;
    while ($i <= MENU_MAX_DEPTH && $j <= MENU_MAX_DEPTH) {
        $expressions[] = array(
            'p' . $i++,
            'p' . $j++,
            array(),
        );
    }
    while ($i <= MENU_MAX_DEPTH) {
        $expressions[] = array(
            'p' . $i++,
            0,
            array(),
        );
    }
    $shift = $item['depth'] - $existing_item['depth'];
    if ($shift > 0) {
        // The order of expressions must be reversed so the new values don't
        // overwrite the old ones before they can be used because "Single-table
        // UPDATE assignments are generally evaluated from left to right"
        // see: http://dev.mysql.com/doc/refman/5.0/en/update.html
        $expressions = array_reverse($expressions);
    }
    foreach ($expressions as $expression) {
        $query->expression($expression[0], $expression[1], $expression[2]);
    }
    $query->expression('depth', 'depth + :depth', array(
        ':depth' => $shift,
    ));
    $query->condition('menu_name', $existing_item['menu_name']);
    $p = 'p1';
    for ($i = 1; $i <= MENU_MAX_DEPTH && $existing_item[$p]; $p = 'p' . ++$i) {
        $query->condition($p, $existing_item[$p]);
    }
    $query->execute();
    // Check the has_children status of the parent, while excluding this item.
    _menu_update_parental_status($existing_item, TRUE);
}

/**
 * Checks and updates the 'has_children' status for the parent of a link.
 */
function _menu_update_parental_status($item, $exclude = FALSE) {
    // If plid == 0, there is nothing to update.
    if ($item['plid']) {
        // Check if at least one visible child exists in the table.
        $query = db_select('menu_links');
        $query->addField('menu_links', 'mlid');
        $query->condition('menu_name', $item['menu_name']);
        $query->condition('hidden', 0);
        $query->condition('plid', $item['plid']);
        $query->range(0, 1);
        if ($exclude) {
            $query->condition('mlid', $item['mlid'], '<>');
        }
        $parent_has_children = (bool) $query->execute()
            ->fetchField() ? 1 : 0;
        db_update('menu_links')->fields(array(
            'has_children' => $parent_has_children,
        ))
            ->condition('mlid', $item['plid'])
            ->execute();
    }
}

/**
 * Sets the p1 through p9 values for a menu link being saved.
 */
function _menu_link_parents_set(&$item, $parent) {
    $i = 1;
    while ($i < $item['depth']) {
        $p = 'p' . $i++;
        $item[$p] = $parent[$p];
    }
    $p = 'p' . $i++;
    // The parent (p1 - p9) corresponding to the depth always equals the mlid.
    $item[$p] = $item['mlid'];
    while ($i <= MENU_MAX_DEPTH) {
        $p = 'p' . $i++;
        $item[$p] = 0;
    }
}

/**
 * Builds the router table based on the data from hook_menu().
 */
function _menu_router_build($callbacks) {
    // First pass: separate callbacks from paths, making paths ready for
    // matching. Calculate fitness, and fill some default values.
    $menu = array();
    $masks = array();
    foreach ($callbacks as $path => $item) {
        $load_functions = array();
        $to_arg_functions = array();
        $fit = 0;
        $move = FALSE;
        $parts = explode('/', $path, MENU_MAX_PARTS);
        $number_parts = count($parts);
        // We store the highest index of parts here to save some work in the fit
        // calculation loop.
        $slashes = $number_parts - 1;
        // Extract load and to_arg functions.
        foreach ($parts as $k => $part) {
            $match = FALSE;
            // Look for wildcards in the form allowed to be used in PHP functions,
            // because we are using these to construct the load function names.
            if (preg_match('/^%(|' . DRUPAL_PHP_FUNCTION_PATTERN . ')$/', $part, $matches)) {
                if (empty($matches[1])) {
                    $match = TRUE;
                    $load_functions[$k] = NULL;
                }
                else {
                    if (function_exists($matches[1] . '_to_arg')) {
                        $to_arg_functions[$k] = $matches[1] . '_to_arg';
                        $load_functions[$k] = NULL;
                        $match = TRUE;
                    }
                    if (function_exists($matches[1] . '_load')) {
                        $function = $matches[1] . '_load';
                        // Create an array of arguments that will be passed to the _load
                        // function when this menu path is checked, if 'load arguments'
                        // exists.
                        $load_functions[$k] = isset($item['load arguments']) ? array(
                            $function => $item['load arguments'],
                        ) : $function;
                        $match = TRUE;
                    }
                }
            }
            if ($match) {
                $parts[$k] = '%';
            }
            else {
                $fit |= 1 << $slashes - $k;
            }
        }
        if ($fit) {
            $move = TRUE;
        }
        else {
            // If there is no %, it fits maximally.
            $fit = (1 << $number_parts) - 1;
        }
        $masks[$fit] = 1;
        $item['_load_functions'] = $load_functions;
        $item['to_arg_functions'] = empty($to_arg_functions) ? '' : serialize($to_arg_functions);
        $item += array(
            'title' => '',
            'weight' => 0,
            'type' => MENU_NORMAL_ITEM,
            'module' => '',
            '_number_parts' => $number_parts,
            '_parts' => $parts,
            '_fit' => $fit,
        );
        $item += array(
            '_visible' => (bool) ($item['type'] & MENU_VISIBLE_IN_BREADCRUMB),
            '_tab' => (bool) ($item['type'] & MENU_IS_LOCAL_TASK),
        );
        if ($move) {
            $new_path = implode('/', $item['_parts']);
            $menu[$new_path] = $item;
            $sort[$new_path] = $number_parts;
        }
        else {
            $menu[$path] = $item;
            $sort[$path] = $number_parts;
        }
    }
    array_multisort($sort, SORT_NUMERIC, $menu);
    // Apply inheritance rules.
    foreach ($menu as $path => $v) {
        $item =& $menu[$path];
        if (!$item['_tab']) {
            // Non-tab items.
            $item['tab_parent'] = '';
            $item['tab_root'] = $path;
        }
        elseif (!isset($item['context'])) {
            $item['context'] = MENU_CONTEXT_PAGE;
        }
        for ($i = $item['_number_parts'] - 1; $i; $i--) {
            $parent_path = implode('/', array_slice($item['_parts'], 0, $i));
            if (isset($menu[$parent_path])) {
                $parent =& $menu[$parent_path];
                // If we have no menu name, try to inherit it from parent items.
                if (!isset($item['menu_name'])) {
                    // If the parent item of this item does not define a menu name (and no
                    // previous iteration assigned one already), try to find the menu name
                    // of the parent item in the currently stored menu links.
                    if (!isset($parent['menu_name'])) {
                        $menu_name = db_query("SELECT menu_name FROM {menu_links} WHERE router_path = :router_path AND module = 'system'", array(
                            ':router_path' => $parent_path,
                        ))->fetchField();
                        if ($menu_name) {
                            $parent['menu_name'] = $menu_name;
                        }
                    }
                    // If the parent item defines a menu name, inherit it.
                    if (!empty($parent['menu_name'])) {
                        $item['menu_name'] = $parent['menu_name'];
                    }
                }
                if (!isset($item['tab_parent'])) {
                    // Parent stores the parent of the path.
                    $item['tab_parent'] = $parent_path;
                }
                if (!isset($item['tab_root']) && !$parent['_tab']) {
                    $item['tab_root'] = $parent_path;
                }
                // If an access callback is not found for a default local task we use
                // the callback from the parent, since we expect them to be identical.
                // In all other cases, the access parameters must be specified.
                if ($item['type'] == MENU_DEFAULT_LOCAL_TASK && !isset($item['access callback']) && isset($parent['access callback'])) {
                    $item['access callback'] = $parent['access callback'];
                    if (!isset($item['access arguments']) && isset($parent['access arguments'])) {
                        $item['access arguments'] = $parent['access arguments'];
                    }
                }
                // Same for page callbacks.
                if (!isset($item['page callback']) && isset($parent['page callback'])) {
                    $item['page callback'] = $parent['page callback'];
                    if (!isset($item['page arguments']) && isset($parent['page arguments'])) {
                        $item['page arguments'] = $parent['page arguments'];
                    }
                    if (!isset($item['file path']) && isset($parent['file path'])) {
                        $item['file path'] = $parent['file path'];
                    }
                    if (!isset($item['file']) && isset($parent['file'])) {
                        $item['file'] = $parent['file'];
                        if (empty($item['file path']) && isset($item['module']) && isset($parent['module']) && $item['module'] != $parent['module']) {
                            $item['file path'] = drupal_get_path('module', $parent['module']);
                        }
                    }
                }
                // Same for delivery callbacks.
                if (!isset($item['delivery callback']) && isset($parent['delivery callback'])) {
                    $item['delivery callback'] = $parent['delivery callback'];
                }
                // Same for theme callbacks.
                if (!isset($item['theme callback']) && isset($parent['theme callback'])) {
                    $item['theme callback'] = $parent['theme callback'];
                    if (!isset($item['theme arguments']) && isset($parent['theme arguments'])) {
                        $item['theme arguments'] = $parent['theme arguments'];
                    }
                }
                // Same for load arguments: if a loader doesn't have any explict
                // arguments, try to find arguments in the parent.
                if (!isset($item['load arguments'])) {
                    foreach ($item['_load_functions'] as $k => $function) {
                        // This loader doesn't have any explict arguments...
                        if (!is_array($function)) {
                            // ... check the parent for a loader at the same position
                            // using the same function name and defining arguments...
                            if (isset($parent['_load_functions'][$k]) && is_array($parent['_load_functions'][$k]) && key($parent['_load_functions'][$k]) === $function) {
                                // ... and inherit the arguments on the child.
                                $item['_load_functions'][$k] = $parent['_load_functions'][$k];
                            }
                        }
                    }
                }
            }
        }
        if (!isset($item['access callback']) && isset($item['access arguments'])) {
            // Default callback.
            $item['access callback'] = 'user_access';
        }
        if (!isset($item['access callback']) || empty($item['page callback'])) {
            $item['access callback'] = 0;
        }
        if (is_bool($item['access callback'])) {
            $item['access callback'] = intval($item['access callback']);
        }
        $item['load_functions'] = empty($item['_load_functions']) ? '' : serialize($item['_load_functions']);
        $item += array(
            'access arguments' => array(),
            'access callback' => '',
            'page arguments' => array(),
            'page callback' => '',
            'delivery callback' => '',
            'title arguments' => array(),
            'title callback' => 't',
            'theme arguments' => array(),
            'theme callback' => '',
            'description' => '',
            'position' => '',
            'context' => 0,
            'tab_parent' => '',
            'tab_root' => $path,
            'path' => $path,
            'file' => '',
            'file path' => '',
            'include file' => '',
        );
        // Calculate out the file to be included for each callback, if any.
        if ($item['file']) {
            $file_path = $item['file path'] ? $item['file path'] : drupal_get_path('module', $item['module']);
            $item['include file'] = $file_path . '/' . $item['file'];
        }
    }
    // Sort the masks so they are in order of descending fit.
    $masks = array_keys($masks);
    rsort($masks);
    return array(
        $menu,
        $masks,
    );
}

/**
 * Saves data from menu_router_build() to the router table.
 */
function _menu_router_save($menu, $masks) {
    // Delete the existing router since we have some data to replace it.
    db_truncate('menu_router')->execute();
    // Prepare insert object.
    $insert = db_insert('menu_router')->fields(array(
        'path',
        'load_functions',
        'to_arg_functions',
        'access_callback',
        'access_arguments',
        'page_callback',
        'page_arguments',
        'delivery_callback',
        'fit',
        'number_parts',
        'context',
        'tab_parent',
        'tab_root',
        'title',
        'title_callback',
        'title_arguments',
        'theme_callback',
        'theme_arguments',
        'type',
        'description',
        'position',
        'weight',
        'include_file',
    ));
    $num_records = 0;
    foreach ($menu as $path => $item) {
        // Fill in insert object values.
        $insert->values(array(
            'path' => $item['path'],
            'load_functions' => $item['load_functions'],
            'to_arg_functions' => $item['to_arg_functions'],
            'access_callback' => $item['access callback'],
            'access_arguments' => serialize($item['access arguments']),
            'page_callback' => $item['page callback'],
            'page_arguments' => serialize($item['page arguments']),
            'delivery_callback' => $item['delivery callback'],
            'fit' => $item['_fit'],
            'number_parts' => $item['_number_parts'],
            'context' => $item['context'],
            'tab_parent' => $item['tab_parent'],
            'tab_root' => $item['tab_root'],
            'title' => $item['title'],
            'title_callback' => $item['title callback'],
            'title_arguments' => $item['title arguments'] ? serialize($item['title arguments']) : '',
            'theme_callback' => $item['theme callback'],
            'theme_arguments' => serialize($item['theme arguments']),
            'type' => $item['type'],
            'description' => $item['description'],
            'position' => $item['position'],
            'weight' => (int) $item['weight'],
            'include_file' => $item['include file'],
        ));
        // Execute in batches to avoid the memory overhead of all of those records
        // in the query object.
        if (++$num_records == 20) {
            $insert->execute();
            $num_records = 0;
        }
    }
    // Insert any remaining records.
    $insert->execute();
    // Store the masks.
    variable_set('menu_masks', $masks);
    return $menu;
}

/**
 * Checks whether the site is in maintenance mode.
 *
 * This function will log the current user out and redirect to front page
 * if the current user has no 'access site in maintenance mode' permission.
 *
 * @param $check_only
 *   If this is set to TRUE, the function will perform the access checks and
 *   return the site offline status, but not log the user out or display any
 *   messages.
 *
 * @return
 *   FALSE if the site is not in maintenance mode, the user login page is
 *   displayed, or the user has the 'access site in maintenance mode'
 *   permission. TRUE for anonymous users not being on the login page when the
 *   site is in maintenance mode.
 */
function _menu_site_is_offline($check_only = FALSE) {
    // Check if site is in maintenance mode.
    if (variable_get('maintenance_mode', 0)) {
        if (user_access('access site in maintenance mode')) {
            // Ensure that the maintenance mode message is displayed only once
            // (allowing for page redirects) and specifically suppress its display on
            // the maintenance mode settings page.
            if (!$check_only && $_GET['q'] != 'admin/config/development/maintenance') {
                if (user_access('administer site configuration')) {
                    drupal_set_message(t('Operating in maintenance mode. <a href="@url">Go online.</a>', array(
                        '@url' => url('admin/config/development/maintenance'),
                    )), 'status', FALSE);
                }
                else {
                    drupal_set_message(t('Operating in maintenance mode.'), 'status', FALSE);
                }
            }
        }
        else {
            return TRUE;
        }
    }
    return FALSE;
}

/**
 * @} End of "defgroup menu".
 */

Functions

Title Deprecated Summary
drupal_help_arg Generates elements for the $arg array in the help hook.
menu_build_tree Builds a menu tree, translates links, and checks access.
menu_cache_clear Clears the cached data for a single named menu.
menu_cache_clear_all Clears all cached menu data.
menu_contextual_links Retrieves contextual links for a path based on registered local tasks.
menu_delete_links Deletes all links for a menu.
menu_execute_active_handler Execute the page callback associated with the current path.
menu_get_active_breadcrumb Gets the breadcrumb for the current page, as determined by the active trail.
menu_get_active_help Returns the help associated with the active menu item.
menu_get_active_menu_names Gets the active menu for the current page.
menu_get_active_title Gets the title of the current page, as determined by the active trail.
menu_get_active_trail Gets the active trail (path to root menu root) of the current page.
menu_get_ancestors Returns the ancestors (and relevant placeholders) for any given path.
menu_get_custom_theme Gets the custom theme for the current page, if there is one.
menu_get_item Gets a router item.
menu_get_names Build a list of named menus.
menu_get_object Gets a loaded object from a router item.
menu_get_router Gets the menu router.
menu_links_clone Clones an array of menu links.
menu_link_children_relative_depth Finds the depth of an item's children relative to its depth.
menu_link_delete Delete one or several menu links.
menu_link_get_preferred Looks up the preferred menu link for a given system path.
menu_link_load Gets a translated, access-checked menu link that is ready for rendering.
menu_link_maintain Inserts, updates, or deletes an uncustomized menu link related to a module.
menu_link_save Saves a menu link.
menu_list_system_menus Returns an array containing the names of system-defined (default) menus.
menu_load_links Returns an array containing all links for a menu.
menu_local_actions Returns the rendered local actions at the current level.
menu_local_tabs Returns a renderable element for the primary and secondary tabs.
menu_local_tasks Collects the local tasks (tabs), action links, and the root path.
menu_main_menu Returns an array of links to be rendered as the Main menu.
menu_navigation_links Returns an array of links for a navigation menu.
menu_primary_local_tasks Returns the rendered local tasks at the top level.
menu_rebuild Populates the database tables used by various menu functions.
menu_reset_static_cache Resets the menu system static cache.
menu_router_build Collects and alters the menu definitions.
menu_secondary_local_tasks Returns the rendered local tasks at the second level.
menu_secondary_menu Returns an array of links to be rendered as the Secondary links.
menu_set_active_item Sets the active path, which determines which page is loaded.
menu_set_active_menu_names Sets (or gets) the active menu for the current page.
menu_set_active_trail Sets the active trail (path to the menu tree root) of the current page.
menu_set_custom_theme Sets a custom theme for the current page, if there is one.
menu_set_item Replaces the statically cached item for a given path.
menu_tab_root_path Returns the router path, or the path for a default local task's parent.
menu_tail_load Loads the path as one string relative to the current index.
menu_tail_to_arg Returns a string containing the path relative to the current index.
menu_tree Renders a menu tree based on the current path.
menu_tree_all_data Gets the data structure representing a named menu tree.
menu_tree_check_access Checks access and performs dynamic operations for each link in the tree.
menu_tree_collect_node_links Collects node links from a given menu tree recursively.

Constants

Title Deprecated Summary
MENU_ACCESS_DENIED Menu status code -- Access denied.
MENU_CALLBACK Menu type -- A hidden, internal callback, typically used for API calls.
MENU_CONTEXT_INLINE Internal menu flag: Local task should be displayed inline.
MENU_CONTEXT_NONE Internal menu flag: Invisible local task.
MENU_CONTEXT_PAGE Internal menu flag: Local task should be displayed in page context.
MENU_CREATED_BY_ADMIN Internal menu flag -- menu item was created by administrator.
MENU_DEFAULT_LOCAL_TASK Menu type -- The "default" local task, which is initially active.
MENU_FOUND Internal menu status code -- Menu item was found.
MENU_IS_LOCAL_ACTION Internal menu flag -- menu item is a local action.
MENU_IS_LOCAL_TASK Internal menu flag -- menu item is a local task.
MENU_IS_ROOT Internal menu flag -- menu item is the root of the menu tree.
MENU_LINKS_TO_PARENT Internal menu flag -- menu item links back to its parent.
MENU_LOCAL_ACTION Menu type -- An action specific to the parent, usually rendered as a link.
MENU_LOCAL_TASK Menu type -- A task specific to the parent item, usually rendered as a tab.
MENU_MAX_DEPTH The maximum depth of a menu links tree - matches the number of p columns.
MENU_MAX_PARTS The maximum number of path elements for a menu callback
MENU_MODIFIED_BY_ADMIN Internal menu flag -- menu item can be modified by administrator.
MENU_NORMAL_ITEM Menu type -- A "normal" menu item that's shown in menu and breadcrumbs.
MENU_NOT_FOUND Menu status code -- Not found.
MENU_PREFERRED_LINK Reserved key to identify the most specific menu link for a given path.
MENU_SITE_OFFLINE Internal menu status code -- Menu item inaccessible because site is offline.
MENU_SITE_ONLINE Internal menu status code -- Everything is working fine.
MENU_SUGGESTED_ITEM Menu type -- A normal menu item, hidden until enabled by an administrator.
MENU_VISIBLE_IN_BREADCRUMB Internal menu flag -- menu item is visible in the breadcrumb.
MENU_VISIBLE_IN_TREE Internal menu flag -- menu item is visible in the menu tree.

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