<?php

/**

 * @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_boot() or hook exit() can make them available, by

 * executing "drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);".

 */

/**

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

 */

function drupal_path_initialize() {

  // Ensure $_GET['q'] is set before calling drupal_normal_path(), to support

  // path caching with hook_url_inbound_alter().

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

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

  }

  $_GET['q'] = drupal_get_normal_path($_GET['q']);

}

/**

 * 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 = NULL) {

  global $language_url;

  // Use the advanced drupal_static() pattern, since this is called very often.

  static $drupal_static_fast;

  if (!isset($drupal_static_fast)) {

    $drupal_static_fast['cache'] = &drupal_static(__FUNCTION__);

  }

  $cache = &$drupal_static_fast['cache'];

  if (!isset($cache)) {

    $cache = array(

      'map' => array(),

      'no_source' => array(),

      'whitelist' => NULL,

      'system_paths' => array(),

      'no_aliases' => array(),

      'first_call' => TRUE,

    );

  }

  // Retrieve the path alias whitelist.

  if (!isset($cache['whitelist'])) {

    $cache['whitelist'] = variable_get('path_alias_whitelist', NULL);

    if (!isset($cache['whitelist'])) {

      $cache['whitelist'] = drupal_path_alias_whitelist_rebuild();

    }

  }

  // If no language is explicitly specified we default to the current URL

  // language. If we used a language different from the one conveyed by the

  // requested URL, we might end up being unable to check if there is a path

  // alias matching the URL path.

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

  if ($action == 'wipe') {

    $cache = array();

    $cache['whitelist'] = drupal_path_alias_whitelist_rebuild();

  }

  elseif ($cache['whitelist'] && $path != '') {

    if ($action == 'alias') {

      // During the first call to drupal_lookup_path() per language, load the

      // expected system paths for the page from cache.

      if (!empty($cache['first_call'])) {

        $cache['first_call'] = FALSE;

        $cache['map'][$path_language] = array();

        // Load system paths from cache.

        $cid = current_path();

        if ($cached = cache_get($cid, 'cache_path')) {

          $cache['system_paths'] = $cached->data;

          // Now fetch the aliases corresponding to these system paths.

          $args = array(

            ':system' => $cache['system_paths'],

            ':language' => $path_language,

            ':language_none' => LANGUAGE_NONE,

          );

          // Always get the language-specific alias before the language-neutral

          // one. For example 'de' is less than 'und' so the order needs to be

          // ASC, while 'xx-lolspeak' is more than 'und' so the order needs to

          // be DESC. We also order by pid ASC so that fetchAllKeyed() returns

          // the most recently created alias for each source. Subsequent queries

          // using fetchField() must use pid DESC to have the same effect.

          // For performance reasons, the query builder is not used here.

          if ($path_language == LANGUAGE_NONE) {

            // Prevent PDO from complaining about a token the query doesn't use.

            unset($args[':language']);

            $result = db_query('SELECT source, alias FROM {url_alias} WHERE source IN (:system) AND language = :language_none ORDER BY pid ASC', $args);

          }

          elseif ($path_language < LANGUAGE_NONE) {

            $result = db_query('SELECT source, alias FROM {url_alias} WHERE source IN (:system) AND language IN (:language, :language_none) ORDER BY language ASC, pid ASC', $args);

          }

          else {

            $result = db_query('SELECT source, alias FROM {url_alias} WHERE source IN (:system) AND language IN (:language, :language_none) ORDER BY language DESC, pid ASC', $args);

          }

          $cache['map'][$path_language] = $result->fetchAllKeyed();

          // Keep a record of paths with no alias to avoid querying twice.

          $cache['no_aliases'][$path_language] = array_flip(array_diff_key($cache['system_paths'], array_keys($cache['map'][$path_language])));

        }

      }

      // If the alias has already been loaded, return it.

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

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

      }

      // Check the path whitelist, if the top_level part before the first /

      // is not in the list, then there is no need to do anything further,

      // it is not in the database.

      elseif (!isset($cache['whitelist'][strtok($path, '/')])) {

        return FALSE;

      }

      // For system paths which were not cached, query aliases individually.

      elseif (!isset($cache['no_aliases'][$path_language][$path])) {

        $args = array(

          ':source' => $path,

          ':language' => $path_language,

          ':language_none' => LANGUAGE_NONE,

        );

        // See the queries above.

        if ($path_language == LANGUAGE_NONE) {

          unset($args[':language']);

          $alias = db_query("SELECT alias FROM {url_alias} WHERE source = :source AND language = :language_none ORDER BY pid DESC", $args)->fetchField();

        }

        elseif ($path_language > LANGUAGE_NONE) {

          $alias = db_query("SELECT alias FROM {url_alias} WHERE source = :source AND language IN (:language, :language_none) ORDER BY language DESC, pid DESC", $args)->fetchField();

        }

        else {

          $alias = db_query("SELECT alias FROM {url_alias} WHERE source = :source AND language IN (:language, :language_none) ORDER BY language ASC, pid DESC", $args)->fetchField();

        }

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

        return $alias;

      }

    }

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

    // isn't a path that has this alias

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

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

      $source = FALSE;

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

        $args = array(

          ':alias' => $path,

          ':language' => $path_language,

          ':language_none' => LANGUAGE_NONE,

        );

        // See the queries above.

        if ($path_language == LANGUAGE_NONE) {

          unset($args[':language']);

          $result = db_query("SELECT source FROM {url_alias} WHERE alias = :alias AND language = :language_none ORDER BY pid DESC", $args);

        }

        elseif ($path_language > LANGUAGE_NONE) {

          $result = db_query("SELECT source FROM {url_alias} WHERE alias = :alias AND language IN (:language, :language_none) ORDER BY language DESC, pid DESC", $args);

        }

        else {

          $result = db_query("SELECT source FROM {url_alias} WHERE alias = :alias AND language IN (:language, :language_none) ORDER BY language ASC, pid DESC", $args);

        }

        if ($source = $result->fetchField()) {

          $cache['map'][$path_language][$source] = $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_source.

          $cache['no_source'][$path_language][$path] = TRUE;

        }

      }

      return $source;

    }

  }

  return FALSE;

}

/**

 * Cache system paths for a page.

 *

 * Cache an array of the system paths available on each page. We assume

 * that aliases will be needed for the majority of these paths during

 * subsequent requests, and load them in a single query during

 * drupal_lookup_path().

 */

function drupal_cache_system_paths() {

  // Check if the system paths for this page were loaded from cache in this

  // request to avoid writing to cache on every request.

  $cache = &drupal_static('drupal_lookup_path', array());

  if (empty($cache['system_paths']) && !empty($cache['map'])) {

    // Generate a cache ID (cid) specifically for this page.

    $cid = current_path();

    // The static $map array used by drupal_lookup_path() includes all

    // system paths for the page request.

    if ($paths = current($cache['map'])) {

      $data = array_keys($paths);

      $expire = REQUEST_TIME + (60 * 60 * 24);

      cache_set($cid, $data, 'cache_path', $expire);

    }

  }

}

/**

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

 *

 * If no path is provided, the function will return the alias of the current

 * page.

 *

 * @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 = NULL, $path_language = NULL) {

  // If no path is specified, use the current page's path.

  if ($path == NULL) {

    $path = $_GET['q'];

  }

  $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 = NULL) {

  $original_path = $path;

  // Lookup the path alias first.

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

    $path = $source;

  }

  // Allow other modules to alter the inbound URL. We cannot use drupal_alter()

  // here because we need to run hook_url_inbound_alter() in the reverse order

  // of hook_url_outbound_alter().

  foreach (array_reverse(module_implements('url_inbound_alter')) as $module) {

    $function = $module . '_url_inbound_alter';

    $function($path, $original_path, $path_language);

  }

  return $path;

}

/**

 * 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() {

  // Use the advanced drupal_static() pattern, since this is called very often.

  static $drupal_static_fast;

  if (!isset($drupal_static_fast)) {

    $drupal_static_fast['is_front_page'] = &drupal_static(__FUNCTION__);

  }

  $is_front_page = &$drupal_static_fast['is_front_page'];

  if (!isset($is_front_page)) {

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

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

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

  }

  return $is_front_page;

}

/**

 * 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) {

  $regexps = &drupal_static(__FUNCTION__);

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

    // Convert path settings to a regular expression.

    // Therefore replace newlines with a logical or, /* with asterisks and the <front> with the frontpage.

    $to_replace = array(

      '/(\r\n?|\n)/', // newlines

      '/\\\\\*/',     // asterisks

      '/(^|\|)\\\\<front\\\\>($|\|)/' // <front>

    );

    $replacements = array(

      '|',

      '.*',

      '\1' . preg_quote(variable_get('site_frontpage', 'node'), '/') . '\2'

    );

    $patterns_quoted = preg_quote($patterns, '/');

    $regexps[$patterns] = '/^(' . preg_replace($to_replace, $replacements, $patterns_quoted) . ')$/';

  }

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

}

/**

 * Return the current URL path of the page being viewed.

 *

 * Examples:

 * - http://example.com/node/306 returns "node/306".

 * - http://example.com/drupalfolder/node/306 returns "node/306" while

 *   base_path() returns "/drupalfolder/".

 * - http://example.com/path/alias (which is a path alias for node/306) returns

 *   "node/306" as opposed to the path alias.

 *

 * This function is not available in hook_boot() so use $_GET['q'] instead.

 * However, be careful when doing that because in the case of Example #3

 * $_GET['q'] will contain "path/alias". If "node/306" is needed, calling

 * drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL) makes this function available.

 *

 * @return

 *   The current Drupal URL path. The path is untrusted user input and must be

 *   treated as such.

 *

 * @see request_path()

 */

function current_path() {

  return $_GET['q'];

}

/**

 * Rebuild the path alias white list.

 *

 * @param $source

 *   An optional system path for which an alias is being inserted.

 *

 * @return

 *   An array containing a white list of path aliases.

 */

function drupal_path_alias_whitelist_rebuild($source = NULL) {

  // When paths are inserted, only rebuild the whitelist if the system path

  // has a top level component which is not already in the whitelist.

  if (!empty($source)) {

    $whitelist = variable_get('path_alias_whitelist', NULL);

    if (isset($whitelist[strtok($source, '/')])) {

      return $whitelist;

    }

  }

  // For each alias in the database, get the top level component of the system

  // path it corresponds to. This is the portion of the path before the first

  // '/', if present, otherwise the whole path itself.

  $whitelist = array();

  $result = db_query("SELECT DISTINCT SUBSTRING_INDEX(source, '/', 1) AS path FROM {url_alias}");

  foreach ($result as $row) {

    $whitelist[$row->path] = TRUE;

  }

  variable_set('path_alias_whitelist', $whitelist);

  return $whitelist;

}

/**

 * Fetches a specific URL alias from the database.

 *

 * @param $conditions

 *   A string representing the source, a number representing the pid, or an

 *   array of query conditions.

 *

 * @return

 *   FALSE if no alias was found or an associative array containing the

 *   following keys:

 *   - source: The internal system path.

 *   - alias: The URL alias.

 *   - pid: Unique path alias identifier.

 *   - language: The language of the alias.

 */

function path_load($conditions) {

  if (is_numeric($conditions)) {

    $conditions = array('pid' => $conditions);

  }

  elseif (is_string($conditions)) {

    $conditions = array('source' => $conditions);

  }

  elseif (!is_array($conditions)) {

    return FALSE;

  }

  $select = db_select('url_alias');

  foreach ($conditions as $field => $value) {

    $select->condition($field, $value);

  }

  return $select

    ->fields('url_alias')

    ->execute()

    ->fetchAssoc();

}

/**

 * Save a path alias to the database.

 *

 * @param $path

 *   An associative array containing the following keys:

 *   - source: The internal system path.

 *   - alias: The URL alias.

 *   - pid: (optional) Unique path alias identifier.

 *   - language: (optional) The language of the alias.

 */

function path_save(&$path) {

  $path += array('language' => LANGUAGE_NONE);