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menu_breadcrumb.module in Menu Breadcrumb 6

The main file for the menu_breadcrumb module.

By default, Drupal 6 will use the Navigation menu for the breadcrumb. This module allows you to use the menu the current page belongs to for the breadcrumb.

As an added bonus, it also allows you to append the page title to the breadcrumb (either as a clickable url or not) and hide the breadcrumb if it only contains the link to the front page.

Maintained by: Geoffrey de Vlugt <gdevlugt@gmail.com>

File

menu_breadcrumb.module
View source
<?php

/**
 * @file
 * The main file for the menu_breadcrumb module.
 *
 * By default, Drupal 6 will use the Navigation menu for the breadcrumb.
 * This module allows you to use the menu the current page belongs to for
 * the breadcrumb.
 *
 * As an added bonus, it also allows you to append the page title to the
 * breadcrumb (either as a clickable url or not) and hide the breadcrumb
 * if it only contains the link to the front page.
 *
 * Maintained by: Geoffrey de Vlugt <gdevlugt@gmail.com>
 */
define('MENU_BREADCRUMB_REGEX_DEFAULT', '/^book-toc-\\d+$/Books/');
define('MENU_BREADCRUMB_REGEX_MATCH', '%^(/.+/)([^/]+)/$%');

/**
 * Implementation of hook_help().
 */
function menu_breadcrumb_help($path, $arg) {
  $output = '';
  switch ($path) {
    case 'admin/settings/modules#description':
      $output = t('Allows you to use the menu the current page belongs to for the breadcrumb.');
      break;
    case 'admin/settings/menu_breadcrumb':
      $output = t('<p>By default, Drupal 6 will use the Navigation menu for the breadcrumb. This module allows you to use the menu the current page belongs to for the breadcrumb.</p><p>As an added bonus, it also allows you to append the page title to the breadcrumb (either as a clickable url or not) and hide the breadcrumb if it only contains the link to the front page.</p>');
      break;
  }
  return $output;
}

/**
 * Implementation of hook_menu().
 */
function menu_breadcrumb_menu() {
  $items = array();
  $items['admin/settings/menu_breadcrumb'] = array(
    'title' => 'Menu breadcrumb',
    'description' => 'Configure menu breadcrumb.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'menu_breadcrumb_admin_settings_form',
    ),
    'access arguments' => array(
      'administer site configuration',
    ),
    'type' => MENU_NORMAL_ITEM,
  );
  return $items;
}

/**
 * Default menu item.
 * If the module is not yet configured, we only need this
 * as a starting point. This determines the default weight
 * and 'enabled' status for any new menus.
 */
function _menu_breadcrumb_default_menu() {
  return array(
    'menu_breadcrumb_default_menu' => array(
      'enabled' => 1,
      'weight' => 0,
      'type' => 'menu_breadcrumb_default_menu',
    ),
  );
}

/**
 * Get the menu selection configuration.
 *
 * @return
 *   Array of menu selections and weights.
 */
function _menu_breadcrumb_get_menus() {
  static $menus;
  if (!isset($menus)) {

    // Fetch stored or default settings.
    $menus = variable_get('menu_breadcrumb_menus', _menu_breadcrumb_default_menu());

    // Load the pattern match cache (to avoid any unnecessary regex matching).
    // Submitting the settings form requires us to rebuild this cache, as
    // the patterns may have changed.
    $match_cache = variable_get('menu_breadcrumb_pattern_matches', array());
    $match_cache_rebuild = variable_get('menu_breadcrumb_pattern_matches_rebuild', FALSE);
    if ($match_cache_rebuild) {
      variable_set('menu_breadcrumb_pattern_matches_rebuild', FALSE);
      $match_cache_old = $match_cache;
      $match_cache = array();
    }
    else {
      $match_cache_old = array();
    }

    // Find new/unknown menus. If rebuilding the pattern match cache,
    // we also treat previously-matched menus (i.e. those currently
    // 'replaced' by a pattern) as new.
    $drupal_menu_names = menu_get_names();
    $unknown_menu_names = array_diff($drupal_menu_names, array_keys($menus), array_keys($match_cache));
    if ($unknown_menu_names) {
      $new_menus = _menu_breadcrumb_process_unknown_menus($unknown_menu_names, $menus, $match_cache_old, $match_cache_rebuild);
    }
    else {
      $new_menus = array();
    }

    // Check new menus against the patterns.
    if ($match_cache_rebuild) {

      // We need to check all menus (old and new), as the
      // patterns may have been modified.
      $new_menus = array_merge($new_menus, $menus);
      $menus = array();
    }
    if ($new_menus) {

      // $menus and $match_cache are updated by reference.
      _menu_breadcrumb_process_new_menus($new_menus, $menus, $match_cache, $match_cache_rebuild);
    }

    // Remove any defunct menu names. Only visible if we are showing
    // the admin settings form, so don't waste time processing this
    // otherwise.
    if ($_GET['q'] == 'admin/settings/menu_breadcrumb') {
      $current_menu_names = array_merge($drupal_menu_names, array_unique($match_cache), array(
        'menu_breadcrumb_default_menu',
      ));
      $menus_current = array_intersect(array_keys($menus), $current_menu_names);
      $menus = array_intersect_key($menus, array_flip($menus_current));
    }
  }
  return $menus;
}

/**
 * Helper for _menu_breadcrumb_get_menus().
 * Determine whether each 'unknown' menu is genuinely new,
 * or was previously aggregated by a pattern match.
 *
 * @return
 *   Array of new/unknown menus.
 */
function _menu_breadcrumb_process_unknown_menus($unknown_menu_names, $menus, $match_cache_old, $match_cache_rebuild) {
  $new_menus = array();

  // 'devel' and 'admin_menu' cause known issues, and should not
  // be used for breadcrumbs.
  $disabled_by_default = array(
    'devel',
    'admin_menu',
  );

  // consider hook here allowing modules to disable their menu
  // by default.
  foreach ($unknown_menu_names as $menu_name) {
    $previously_matched = $match_cache_rebuild && array_key_exists($menu_name, $match_cache_old) && ($pattern = $match_cache_old[$menu_name]) && array_key_exists($pattern, $menus);
    if ($previously_matched) {

      // Use the known enabled/weight values for this pattern.
      $enabled = $menus[$pattern]['enabled'];
      $weight = $menus[$pattern]['weight'];
    }
    else {

      // A genuinely unknown menu. Use default values.
      $disable = in_array($menu_name, $disabled_by_default, TRUE);
      $enabled = $disable ? FALSE : $menus['menu_breadcrumb_default_menu']['enabled'];
      $weight = $disable ? count($menus) : $menus['menu_breadcrumb_default_menu']['weight'];
    }
    $new_menus[$menu_name] = array(
      'enabled' => $enabled,
      'weight' => $weight,
      'type' => 'menu',
    );
  }
  return $new_menus;
}

/**
 * Helper for _menu_breadcrumb_get_menus().
 * Compare new menus against the defined menu patterns,
 * and update the persistent variable caches accordingly.
 */
function _menu_breadcrumb_process_new_menus($new_menus, &$menus, &$match_cache, $match_cache_rebuild) {

  // Load the current regex patterns.
  $patterns = array();
  $menu_patterns = variable_get('menu_breadcrumb_menu_patterns', MENU_BREADCRUMB_REGEX_DEFAULT);
  $menu_patterns = array_filter(explode("\n", $menu_patterns));
  foreach ($menu_patterns as $pattern) {
    $part = array();

    // Form validation has already ensured these will match.
    preg_match(MENU_BREADCRUMB_REGEX_MATCH, $pattern, $part);
    $regex = $part[1];
    $title = $part[2];
    $patterns[$regex] = $title;
  }

  // Remove any deprecated patterns.
  if ($match_cache_rebuild) {
    foreach ($new_menus as $menu_name => $menu) {
      if ($menu['type'] == 'pattern' && !in_array($menu_name, array_keys($patterns), TRUE)) {
        unset($new_menus[$menu_name]);
      }
    }
  }

  // Aggregate the menus which match the specified patterns.
  if ($patterns) {
    $update_match_cache = FALSE;
    foreach ($patterns as $regex => $title) {
      foreach ($new_menus as $menu_name => $menu) {
        if ($menu['type'] == 'menu') {
          if (preg_match($regex, $menu_name)) {

            // This menu name matches a pattern. Add the pattern
            // itself as a menu entry if it's new.
            if (!array_key_exists($regex, $menus)) {

              // Use existing weight and enabled status.
              $menus[$regex] = $new_menus[$menu_name];
              $menus[$regex]['type'] = 'pattern';
            }

            // Remove the matching name, and update the match cache.
            unset($new_menus[$menu_name]);
            $match_cache[$menu_name] = $regex;
            $update_match_cache = TRUE;
          }
        }
      }

      // We don't have the titles for new patterns yet in
      // 'menu_breadcrumb_menus', so add it now for the settings form.
      if (array_key_exists($regex, $menus)) {
        $menus[$regex]['title'] = $title;
      }
    }
    if ($update_match_cache) {
      variable_set('menu_breadcrumb_pattern_matches', $match_cache);
    }
  }

  // Merge in any remaining new menus that did not match any pattern
  // and update the 'menu_breadcrumb_menus' cache.
  $menus = array_merge($new_menus, $menus);
  foreach (array_keys($menus) as $menu_name) {
    $menus[$menu_name]['name'] = $menu_name;
  }
  uasort($menus, '_menu_breadcrumb_sort');

  // sort by weight.
  variable_set('menu_breadcrumb_menus', $menus);
}

/**
 * Sort-by-weight comparison.
 * Sub-sort by menu_name, for consistency in the settings form.
 */
function _menu_breadcrumb_sort($menu1, $menu2) {
  $menu1_weight = !empty($menu1['weight']) ? $menu1['weight'] : 0;
  $menu2_weight = !empty($menu2['weight']) ? $menu2['weight'] : 0;
  if ($menu1_weight == $menu2_weight) {
    $menu1_name = !empty($menu1['name']) ? $menu1['name'] : "";
    $menu2_name = !empty($menu2['name']) ? $menu2['name'] : "";
    return $menu1_name < $menu2_name ? -1 : 1;
  }
  return $menu1_weight < $menu2_weight ? -1 : 1;
}

/**
 * Get the menu/selection list.
 *
 * @return
 *   An array indicating the enabled status of each menu.
 */
function menu_breadcrumb_menu_list() {
  static $list;
  if (!isset($list)) {
    $menus = _menu_breadcrumb_get_menus();
    unset($menus['menu_breadcrumb_default_menu']);
    $list = array();
    foreach ($menus as $name => $menu) {
      $list[$name] = (bool) $menu['enabled'];
    }

    // Enable other modules to dynamically modify the menu list
    // (for example, to make the order depend upon the current
    // user's language preference).
    if ($hook = module_invoke_all('menu_breadcrumb_menu_list', $list)) {
      $list = $hook;
    }
  }
  return $list;
}

/**
 * Implementation of hook_init().
 *
 * Set the active menu according to the current path.
 */
function menu_breadcrumb_init() {
  $is_front = drupal_is_front_page();
  if (variable_get('menu_breadcrumb_determine_menu', 1) && !$is_front) {

    // Find the set of menus containing a link for the current page.
    $menu_item = menu_get_item();
    $result = db_query("SELECT mlid, menu_name FROM {menu_links} WHERE link_path = '%s'", $menu_item['href']);
    $menu_link_menus = array();
    while ($menu_link = db_fetch_array($result)) {
      $menu_link_menus[$menu_link['menu_name']] = TRUE;
    }

    // Choose the highest-priority 'Enabled' menu.
    $match_cache = variable_get('menu_breadcrumb_pattern_matches', array());
    $menu_list = array_filter(menu_breadcrumb_menu_list());

    // enabled menus.
    foreach (array_keys($menu_list) as $menu_name) {
      $is_pattern = substr($menu_name, 0, 1) == '/' && substr($menu_name, -1, 1) == '/';
      if ($is_pattern) {

        // Look for each of the $menu_link_menus in the pattern match cache.
        foreach (array_keys($menu_link_menus) as $menu_link_menu_name) {
          if (array_key_exists($menu_link_menu_name, $match_cache) && $match_cache[$menu_link_menu_name] == $menu_name) {
            menu_set_active_menu_name($menu_link_menu_name);
            break 2;
          }
        }
      }
      else {
        if (array_key_exists($menu_name, $menu_link_menus)) {
          menu_set_active_menu_name($menu_name);
          break;
        }
      }
    }
  }

  // Generate the breadcrumbs using the active menu.
  $breadcrumb = drupal_get_breadcrumb();
  if (variable_get('menu_breadcrumb_append_node_title', 0) == 1) {
    $node_title = filter_xss(menu_get_active_title(), array());
    if (variable_get('menu_breadcrumb_append_node_url', 0) == 1) {
      $breadcrumb[] = $is_front ? l(t('Home'), '<front>') : l($node_title, $_GET['q'], array(
        'html' => TRUE,
      ));
    }
    else {
      $breadcrumb[] = $is_front ? t('Home') : $node_title;
    }
  }
  if (count($breadcrumb) == 1 && variable_get('menu_breadcrumb_hide_on_single_item', 0)) {
    $breadcrumb = array();
  }
  drupal_set_breadcrumb($breadcrumb);
}

/**
 * Menu breadcrumb admin settings form.
 *
 * @return
 *   The settings form used by Menu breadcrumb.
 */
function menu_breadcrumb_admin_settings_form() {
  $form['menu_breadcrumb_determine_menu'] = array(
    '#type' => 'checkbox',
    '#title' => t('Use menu the page belongs to for the breadcrumb.'),
    '#description' => t('By default, Drupal 6 will use the Navigation menu for the breadcrumb. If you want to use the menu the active page belongs to for the breadcrumb, enable this option.'),
    '#default_value' => variable_get('menu_breadcrumb_determine_menu', 1),
  );
  $form['menu_breadcrumb_append_node_title'] = array(
    '#type' => 'checkbox',
    '#title' => t('Append page title to breadcrumb'),
    '#description' => t('Choose whether or not the page title should be included in the breadcrumb.'),
    '#default_value' => variable_get('menu_breadcrumb_append_node_title', 0),
  );
  $form['menu_breadcrumb_append_node_url'] = array(
    '#type' => 'checkbox',
    '#title' => t('Appended page title as an URL.'),
    '#description' => t('Choose whether or not the appended page title should be an URL.'),
    '#default_value' => variable_get('menu_breadcrumb_append_node_url', 0),
  );
  $form['menu_breadcrumb_hide_on_single_item'] = array(
    '#type' => 'checkbox',
    '#title' => t('Hide the breadcrumb if the breadcrumb only contains the link to the front page.'),
    '#description' => t('Choose whether or not the breadcrumb should be hidden if the breadcrumb only contains a link to the front page (<em>Home</em>.).'),
    '#default_value' => variable_get('menu_breadcrumb_hide_on_single_item', 0),
  );
  $form['include_exclude'] = array(
    '#type' => 'fieldset',
    '#title' => t('Enable / Disable Menus'),
    '#description' => t('The breadcrumb will be generated from the first "enabled" menu that contains a menu item for the page. Re-order the list to change the priority of each menu.'),
  );
  $form['include_exclude']['note_about_navigation'] = array(
    '#type' => 'markup',
    '#prefix' => '<p class="description">',
    '#suffix' => '</p>',
    '#value' => t("Note: If none of the enabled menus contain an item for a given page, Drupal will look in the 'Navigation' menu by default, even if it is 'disabled' here."),
  );

  // Orderable list of menu selections.
  $form['include_exclude']['menu_breadcrumb_menus'] = array(
    '#tree' => TRUE,
    '#theme' => 'menu_breadcrumb_menus_table',
  );

  // Load stored configuration.
  $menus = _menu_breadcrumb_get_menus();
  $weight_delta = count($menus);
  foreach ($menus as $menu_name => $menu) {

    // Load menu titles.
    $title = !empty($menu['title']) ? $menu['title'] : $menu_name;
    if ($menu['type'] == 'menu') {
      $drupal_menu = menu_load($menu_name);
      if (!empty($drupal_menu['title'])) {
        $title = $drupal_menu['title'];
      }
    }

    // Ensure that regex patterns do not cause invalid id attributes.
    $safe_id_prefix = 'edit-menu-breadcrumb-menus-' . menu_breadcrumb_html_id($menu_name);
    $form['include_exclude']['menu_breadcrumb_menus'][$menu_name] = array(
      'enabled' => array(
        '#type' => 'checkbox',
        '#id' => $safe_id_prefix . '-enabled',
        '#title' => '',
        '#default_value' => $menu['enabled'],
      ),
      'label' => array(
        '#value' => $menu_name,
      ),
      'weight' => array(
        '#type' => 'weight',
        '#default_value' => !empty($menu['weight']) ? (int) $menu['weight'] : 0,
        '#delta' => $weight_delta,
        '#id' => $safe_id_prefix . '-weight-wrapper',
      ),
      'type' => array(
        '#type' => 'value',
        '#value' => $menu['type'],
      ),
      'title' => array(
        '#type' => 'value',
        '#value' => $title,
      ),
      'title_display' => array(
        '#type' => 'markup',
        '#value' => check_plain($title),
      ),
    );

    // Provide helpful title attributes for special menus.
    $title_field =& $form['include_exclude']['menu_breadcrumb_menus'][$menu_name]['title_display'];
    if ($menu['type'] == 'pattern') {
      $title_field['#value'] = t('<span title="@title">@name <em>(@hint)</em></span>', array(
        '@title' => t("See 'Advanced' settings below."),
        '@name' => $title_field['#value'],
        '@hint' => t('pattern'),
      ));
    }
    elseif ($menu['type'] == 'menu_breadcrumb_default_menu') {
      $title_field['#value'] = t('<em><span title="@title">@text</span></em>', array(
        '@title' => t('Default setting for future menus.'),
        '@text' => t('Default setting (see below)'),
      ));
    }
  }
  $form['include_exclude']['description'] = array(
    '#type' => 'markup',
    '#prefix' => '<p class="description">',
    '#suffix' => '</p>',
    '#value' => t('<strong>Default setting</strong> is not a real menu - it defines the default position and enabled status for future menus. If it is "enabled", Menu Breadcrumb will automatically consider newly-added menus when establishing breadcrumbs. If it is disabled, new menus will not be used for breadcrumbs until they have explicitly been enabled here.'),
  );
  $form['include_exclude']['advanced'] = array(
    '#type' => 'fieldset',
    '#title' => t('Advanced'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['include_exclude']['advanced']['pattern_help'] = array(
    '#type' => 'markup',
    '#prefix' => '<p class="description">',
    '#suffix' => '</p>',
    '#value' => t("Enter regular expressions (one per line) to aggregate matching menu names into a single replacement title in the above list."),
  );
  $form['include_exclude']['advanced']['menu_breadcrumb_menu_patterns'] = array(
    '#type' => 'textarea',
    '#title' => t('Patterns'),
    '#default_value' => variable_get('menu_breadcrumb_menu_patterns', MENU_BREADCRUMB_REGEX_DEFAULT),
    '#description' => t("Syntax: /regex/title/<br/>e.g.: /^book-toc-\\d+\$/Books/"),
  );

  // Explicitly set our submit handler, due to system_settings_form().
  $form['#submit'][] = 'menu_breadcrumb_admin_settings_form_submit';
  return system_settings_form($form);
}

/**
 * Form validation handler.
 */
function menu_breadcrumb_admin_settings_form_validate($form, &$form_state) {
  $patterns =& $form_state['values']['menu_breadcrumb_menu_patterns'];

  // Filter white-space before saving patterns.
  $patterns = trim($patterns);
  $patterns = preg_replace('/\\s*[\\r\\n]+\\s*/', "\n", $patterns);

  // Check patterns against required syntax.
  if ($patterns) {
    foreach (explode("\n", $patterns) as $pattern) {
      if (!preg_match(MENU_BREADCRUMB_REGEX_MATCH, $pattern)) {
        $t_args = array(
          '%pattern' => $pattern,
          '%regex' => MENU_BREADCRUMB_REGEX_MATCH,
        );
        form_set_error('menu_breadcrumb_menu_patterns', t("Invalid pattern syntax: %pattern does not match %regex", $t_args));
      }
    }
  }
}

/**
 * Form submission handler.
 */
function menu_breadcrumb_admin_settings_form_submit($form, &$form_state) {

  // The menu pattern match cache needs rebuilding, as the
  // pattern definitions may have changed.
  variable_set('menu_breadcrumb_pattern_matches_rebuild', TRUE);
}

/**
 * Implementation of hook_theme().
 */
function menu_breadcrumb_theme() {
  return array(
    'menu_breadcrumb_menus_table' => array(
      'arguments' => array(
        'element' => NULL,
      ),
    ),
  );
}

/**
 * Theme a drag-to-reorder table of menu selection checkboxes.
 */
function theme_menu_breadcrumb_menus_table($element) {
  drupal_add_tabledrag('menu-breadcrumb-menus', 'order', 'sibling', 'menu-weight');
  $header = array(
    t('Menu'),
    t('Enabled'),
    t('Weight'),
  );

  // Generate table of draggable menu names.
  $rows = array();
  foreach (element_children($element) as $menu_name) {
    $element[$menu_name]['weight']['#attributes']['class'] = 'menu-weight';
    $rows[] = array(
      'data' => array(
        drupal_render($element[$menu_name]['title_display']),
        drupal_render($element[$menu_name]['enabled']),
        drupal_render($element[$menu_name]['weight']),
      ),
      'class' => 'draggable',
    );
  }
  return theme('table', $header, $rows, array(
    'id' => 'menu-breadcrumb-menus',
  ));
}

/**
 * Prepare a string for use as a valid HTML ID and guarantee uniqueness.
 * Adapted from Drupal 7's drupal_html_id().
 *
 * @param $id
 *   The ID to clean.
 * @return
 *   The cleaned ID.
 */
function menu_breadcrumb_html_id($id) {
  static $seen_ids = array();
  $id = strtr(drupal_strtolower($id), array(
    ' ' => '-',
    '_' => '-',
    '[' => '-',
    ']' => '',
  ));

  // As defined in http://www.w3.org/TR/html4/types.html#type-name, HTML IDs can
  // only contain letters, digits ([0-9]), hyphens ("-"), underscores ("_"),
  // colons (":"), and periods ("."). We strip out any character not in that
  // list. Note that the CSS spec doesn't allow colons or periods in identifiers
  // (http://www.w3.org/TR/CSS21/syndata.html#characters), so we strip those two
  // characters as well.
  $id = preg_replace('/[^A-Za-z0-9\\-_]/', '', $id);

  // Ensure IDs are unique. The first occurrence is held but left alone.
  // Subsequent occurrences get a number appended to them. This incrementing
  // will almost certainly break code that relies on explicit HTML IDs in forms
  // that appear more than once on the page, but the alternative is outputting
  // duplicate IDs, which would break JS code and XHTML validity anyways. For
  // now, it's an acceptable stopgap solution.
  if (isset($seen_ids[$id])) {
    $id = $id . '-' . ++$seen_ids[$id];
  }
  else {
    $seen_ids[$id] = 1;
  }
  return $id;
}

Functions

Namesort descending Description
menu_breadcrumb_admin_settings_form Menu breadcrumb admin settings form.
menu_breadcrumb_admin_settings_form_submit Form submission handler.
menu_breadcrumb_admin_settings_form_validate Form validation handler.
menu_breadcrumb_help Implementation of hook_help().
menu_breadcrumb_html_id Prepare a string for use as a valid HTML ID and guarantee uniqueness. Adapted from Drupal 7's drupal_html_id().
menu_breadcrumb_init Implementation of hook_init().
menu_breadcrumb_menu Implementation of hook_menu().
menu_breadcrumb_menu_list Get the menu/selection list.
menu_breadcrumb_theme Implementation of hook_theme().
theme_menu_breadcrumb_menus_table Theme a drag-to-reorder table of menu selection checkboxes.
_menu_breadcrumb_default_menu Default menu item. If the module is not yet configured, we only need this as a starting point. This determines the default weight and 'enabled' status for any new menus.
_menu_breadcrumb_get_menus Get the menu selection configuration.
_menu_breadcrumb_process_new_menus Helper for _menu_breadcrumb_get_menus(). Compare new menus against the defined menu patterns, and update the persistent variable caches accordingly.
_menu_breadcrumb_process_unknown_menus Helper for _menu_breadcrumb_get_menus(). Determine whether each 'unknown' menu is genuinely new, or was previously aggregated by a pattern match.
_menu_breadcrumb_sort Sort-by-weight comparison. Sub-sort by menu_name, for consistency in the settings form.

Constants

Namesort descending Description
MENU_BREADCRUMB_REGEX_DEFAULT @file The main file for the menu_breadcrumb module.
MENU_BREADCRUMB_REGEX_MATCH