<?php

// $Id: path.inc,v 1.19.2.1 2008/10/13 21:06:41 dries Exp $

/**

 * @file

 * Functions to handle paths in Drupal, including path aliasing.

 *

 * These functions are not loaded for cached pages, but modules that need

 * to use them in hook_init() or hook exit() can make them available, by

 * executing "drupal_bootstrap(DRUPAL_BOOTSTRAP_PATH);".

 */

/**

 * Initialize the $_GET['q'] variable to the proper normal path.

 */

function drupal_init_path() {

  if (!empty($_GET['q'])) {

    $_GET['q'] = drupal_get_normal_path(trim($_GET['q'], '/'));

  }

  else {

    $_GET['q'] = drupal_get_normal_path(variable_get('site_frontpage', 'node'));

  }

}

/**

 * Given an alias, return its Drupal system URL if one exists. Given a Drupal

 * system URL return one of its aliases if such a one exists. Otherwise,

 * return FALSE.

 *

 * @param $action

 *   One of the following values:

 *   - wipe: delete the alias cache.

 *   - alias: return an alias for a given Drupal system path (if one exists).

 *   - source: return the Drupal system URL for a path alias (if one exists).

 * @param $path

 *   The path to investigate for corresponding aliases or system URLs.

 * @param $path_language

 *   Optional language code to search the path with. Defaults to the page language.

 *   If there's no path defined for that language it will search paths without

 *   language.

 *

 * @return

 *   Either a Drupal system path, an aliased path, or FALSE if no path was

 *   found.

 */

function drupal_lookup_path($action, $path = '', $path_language = '') {

  global $language;

  // $map is an array with language keys, holding arrays of Drupal paths to alias relations

  static $map = array(), $no_src = array(), $count;

  $path_language = $path_language ? $path_language : $language->language;

  // Use $count to avoid looking up paths in subsequent calls if there simply are no aliases

  if (!isset($count)) {

    $count = db_result(db_query('SELECT COUNT(pid) FROM {url_alias}'));

  }

  if ($action == 'wipe') {

    $map = array();

    $no_src = array();

    $count = NULL;

  }

  elseif ($count > 0 && $path != '') {

    if ($action == 'alias') {

      if (isset($map[$path_language][$path])) {

        return $map[$path_language][$path];

      }

      // Get the most fitting result falling back with alias without language

      $alias = db_result(db_query("SELECT dst FROM {url_alias} WHERE src = '%s' AND language IN('%s', '') ORDER BY language DESC", $path, $path_language));

      $map[$path_language][$path] = $alias;

      return $alias;

    }

    // Check $no_src for this $path in case we've already determined that there

    // isn't a path that has this alias

    elseif ($action == 'source' && !isset($no_src[$path_language][$path])) {

      // Look for the value $path within the cached $map

      $src = '';

      if (!isset($map[$path_language]) || !($src = array_search($path, $map[$path_language]))) {

        // Get the most fitting result falling back with alias without language

        if ($src = db_result(db_query("SELECT src FROM {url_alias} WHERE dst = '%s' AND language IN('%s', '') ORDER BY language DESC", $path, $path_language))) {

          $map[$path_language][$src] = $path;

        }

        else {

          // We can't record anything into $map because we do not have a valid

          // index and there is no need because we have not learned anything

          // about any Drupal path. Thus cache to $no_src.

          $no_src[$path_language][$path] = TRUE;

        }

      }

      return $src;

    }

  }

  return FALSE;

}

/**

 * Given an internal Drupal path, return the alias set by the administrator.

 *

 * @param $path

 *   An internal Drupal path.

 * @param $path_language

 *   An optional language code to look up the path in.

 *

 * @return

 *   An aliased path if one was found, or the original path if no alias was

 *   found.

 */

function drupal_get_path_alias($path, $path_language = '') {

  $result = $path;

  if ($alias = drupal_lookup_path('alias', $path, $path_language)) {

    $result = $alias;

  }

  return $result;

}

/**

 * Given a path alias, return the internal path it represents.

 *

 * @param $path

 *   A Drupal path alias.

 * @param $path_language

 *   An optional language code to look up the path in.

 *

 * @return

 *   The internal path represented by the alias, or the original alias if no

 *   internal path was found.

 */

function drupal_get_normal_path($path, $path_language = '') {

  $result = $path;

  if ($src = drupal_lookup_path('source', $path, $path_language)) {

    $result = $src;

  }

  if (function_exists('custom_url_rewrite_inbound')) {

    // Modules may alter the inbound request path by reference.

    custom_url_rewrite_inbound($result, $path, $path_language);

  }

  return $result;

}

/**

 * Return a component of the current Drupal path.

 *

 * When viewing a page at the path "admin/content/types", for example, arg(0)

 * would return "admin", arg(1) would return "content", and arg(2) would return

 * "types".

 *

 * Avoid use of this function where possible, as resulting code is hard to read.

 * Instead, attempt to use named arguments in menu callback functions. See the

 * explanation in menu.inc for how to construct callbacks that take arguments.

 *

 * @param $index

 *   The index of the component, where each component is separated by a '/'

 *   (forward-slash), and where the first component has an index of 0 (zero).

 *

 * @return

 *   The component specified by $index, or NULL if the specified component was

 *   not found.

 */

function arg($index = NULL, $path = NULL) {

  static $arguments;

  if (!isset($path)) {

    $path = $_GET['q'];

  }

  if (!isset($arguments[$path])) {

    $arguments[$path] = explode('/', $path);

  }

  if (!isset($index)) {

    return $arguments[$path];

  }

  if (isset($arguments[$path][$index])) {

    return $arguments[$path][$index];

  }

}

/**

 * Get the title of the current page, for display on the page and in the title bar.

 *

 * @return

 *   The current page's title.

 */

function drupal_get_title() {

  $title = drupal_set_title();

  // during a bootstrap, menu.inc is not included and thus we cannot provide a title

  if (!isset($title) && function_exists('menu_get_active_title')) {

    $title = check_plain(menu_get_active_title());

  }

  return $title;

}

/**

 * Set the title of the current page, for display on the page and in the title bar.

 *

 * @param $title

 *   Optional string value to assign to the page title; or if set to NULL

 *   (default), leaves the current title unchanged.

 *

 * @return

 *   The updated title of the current page.

 */

function drupal_set_title($title = NULL) {

  static $stored_title;

  if (isset($title)) {

    $stored_title = $title;

  }

  return $stored_title;

}

/**

 * Check if the current page is the front page.

 *

 * @return

 *   Boolean value: TRUE if the current page is the front page; FALSE if otherwise.

 */

function drupal_is_front_page() {

  // As drupal_init_path updates $_GET['q'] with the 'site_frontpage' path,

  // we can check it against the 'site_frontpage' variable.

  return $_GET['q'] == drupal_get_normal_path(variable_get('site_frontpage', 'node'));

}

/**

 * Check if a path matches any pattern in a set of patterns.

 *

 * @param $path

 *   The path to match.

 * @param $patterns

 *   String containing a set of patterns separated by \n, \r or \r\n.

 *

 * @return

 *   Boolean value: TRUE if the path matches a pattern, FALSE otherwise.

 */

function drupal_match_path($path, $patterns) {

  static $regexps;

  if (!isset($regexps[$patterns])) {

    $regexps[$patterns] = '/^('. preg_replace(array('/(\r\n?|\n)/', '/\\\\\*/', '/(^|\|)\\\\<front\\\\>($|\|)/'), array('|', '.*', '\1'. preg_quote(variable_get('site_frontpage', 'node'), '/') .'\2'), preg_quote($patterns, '/')) .')$/';

  }

  return preg_match($regexps[$patterns], $path);

}