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UpdateVersionSubscriber.php

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    common.inc 185.03 KiB
    <?php
    // $Id$
    
    /**
     * @file
     * Common functions that many Drupal modules will need to reference.
     *
     * The functions that are critical and need to be available even when serving
     * a cached page are instead located in bootstrap.inc.
     */
    
    /**
     * Error reporting level: display no errors.
     */
    define('ERROR_REPORTING_HIDE', 0);
    
    /**
     * Error reporting level: display errors and warnings.
     */
    define('ERROR_REPORTING_DISPLAY_SOME', 1);
    
    /**
     * Error reporting level: display all messages.
     */
    define('ERROR_REPORTING_DISPLAY_ALL', 2);
    
    /**
     * Return status for saving which involved creating a new item.
     */
    define('SAVED_NEW', 1);
    
    /**
     * Return status for saving which involved an update to an existing item.
     */
    define('SAVED_UPDATED', 2);
    
    /**
     * Return status for saving which deleted an existing item.
     */
    define('SAVED_DELETED', 3);
    
    /**
     * The default weight of system CSS files added to the page.
     */
    define('CSS_SYSTEM', -100);
    
    /**
     * The default weight of CSS files added to the page.
     */
    define('CSS_DEFAULT', 0);
    
    /**
     * The default weight of theme CSS files added to the page.
     */
    define('CSS_THEME', 100);
    
    /**
     * The weight of JavaScript libraries, settings or jQuery plugins being
     * added to the page.
     */
    define('JS_LIBRARY', -100);
    
    /**
     * The default weight of JavaScript being added to the page.
     */
    define('JS_DEFAULT', 0);
    
    /**
     * The weight of theme JavaScript code being added to the page.
     */
    define('JS_THEME', 100);
    
    /**
     * Error code indicating that the request made by drupal_http_request() exceeded
     * the specified timeout.
     */
    define('HTTP_REQUEST_TIMEOUT', 1);
    
    /**
     * Constants defining cache granularity for blocks and renderable arrays.
     *
     * Modules specify the caching patterns for their blocks using binary
     * combinations of these constants in their hook_block_info():
     *   $block[delta]['cache'] = DRUPAL_CACHE_PER_ROLE | DRUPAL_CACHE_PER_PAGE;
     * DRUPAL_CACHE_PER_ROLE is used as a default when no caching pattern is
     * specified. Use DRUPAL_CACHE_CUSTOM to disable standard block cache and
     * implement
     *
     * The block cache is cleared in cache_clear_all(), and uses the same clearing
     * policy than page cache (node, comment, user, taxonomy added or updated...).
     * Blocks requiring more fine-grained clearing might consider disabling the
     * built-in block cache (DRUPAL_NO_CACHE) and roll their own.
     *
     * Note that user 1 is excluded from block caching.
     */
    
    /**
     * The block should not get cached. This setting should be used:
     * - for simple blocks (notably those that do not perform any db query),
     * where querying the db cache would be more expensive than directly generating
     * the content.
     * - for blocks that change too frequently.
     */
    define('DRUPAL_NO_CACHE', -1);
    
    /**
     * The block is handling its own caching in its hook_block_view(). From the
     * perspective of the block cache system, this is equivalent to DRUPAL_NO_CACHE.
     * Useful when time based expiration is needed or a site uses a node access
     * which invalidates standard block cache.
     */
    define('DRUPAL_CACHE_CUSTOM', -2);
    
    /**
     * The block or element can change depending on the roles the user viewing the
     * page belongs to. This is the default setting for blocks, used when the block
     * does not specify anything.
     */
    define('DRUPAL_CACHE_PER_ROLE', 0x0001);
    
    /**
     * The block or element can change depending on the user viewing the page.
     * This setting can be resource-consuming for sites with large number of users,
     * and thus should only be used when DRUPAL_CACHE_PER_ROLE is not sufficient.
     */
    define('DRUPAL_CACHE_PER_USER', 0x0002);
    
    /**
     * The block or element can change depending on the page being viewed.
     */
    define('DRUPAL_CACHE_PER_PAGE', 0x0004);
    
    /**
     * The block or element is the same for every user on every page where it is visible.
     */
    define('DRUPAL_CACHE_GLOBAL', 0x0008);
    
    /**
     * Add content to a specified region.
     *
     * @param $region
     *   Page region the content is added to.
     * @param $data
     *   Content to be added.
     */
    function drupal_add_region_content($region = NULL, $data = NULL) {
      static $content = array();
    
      if (!is_null($region) && !is_null($data)) {
        $content[$region][] = $data;
      }
      return $content;
    }
    
    /**
     * Get assigned content for a given region.
     *
     * @param $region
     *   A specified region to fetch content for. If NULL, all regions will be
     *   returned.
     * @param $delimiter
     *   Content to be inserted between imploded array elements.
     */
    function drupal_get_region_content($region = NULL, $delimiter = ' ') {
      $content = drupal_add_region_content();
      if (isset($region)) {
        if (isset($content[$region]) && is_array($content[$region])) {
          return implode($delimiter, $content[$region]);
        }
      }
      else {
        foreach (array_keys($content) as $region) {
          if (is_array($content[$region])) {
            $content[$region] = implode($delimiter, $content[$region]);
          }
        }
        return $content;
      }
    }
    
    /**
     * Get the name of the currently active install profile.
     *
     * When this function is called during Drupal's initial installation process,
     * the name of the profile that's about to be installed is stored in the global
     * installation state. At all other times, the standard Drupal systems variable
     * table contains the name of the current profile, and we can call variable_get()
     * to determine what one is active.
     *
     * @return $profile
     *   The name of the install profile.
     */
    function drupal_get_profile() {
      global $install_state;
    
      if (isset($install_state['parameters']['profile'])) {
        $profile = $install_state['parameters']['profile'];
      }
      else {
        $profile = variable_get('install_profile', 'default');
      }
    
      return $profile;
    }
    
    
    /**
     * Set the breadcrumb trail for the current page.
     *
     * @param $breadcrumb
     *   Array of links, starting with "home" and proceeding up to but not including
     *   the current page.
     */
    function drupal_set_breadcrumb($breadcrumb = NULL) {
      $stored_breadcrumb = &drupal_static(__FUNCTION__);
    
      if (!is_null($breadcrumb)) {
        $stored_breadcrumb = $breadcrumb;
      }
      return $stored_breadcrumb;
    }
    
    /**
     * Get the breadcrumb trail for the current page.
     */
    function drupal_get_breadcrumb() {
      $breadcrumb = drupal_set_breadcrumb();
    
      if (is_null($breadcrumb)) {
        $breadcrumb = menu_get_active_breadcrumb();
      }
    
      return $breadcrumb;
    }
    
    /**
     * Return a string containing RDF namespaces for the <html> tag of an XHTML
     * page.
     */
    function drupal_get_rdf_namespaces() {
      // Serialize the RDF namespaces used in RDFa annotation.
      $xml_rdf_namespaces = array();
      foreach (module_invoke_all('rdf_namespaces') as $prefix => $uri) {
        $xml_rdf_namespaces[] = 'xmlns:' . $prefix . '="' . $uri . '"';
      }
      return implode("\n  ", $xml_rdf_namespaces);
    }
    
    /**
     * Add output to the head tag of the HTML page.
     *
     * This function can be called as long the headers aren't sent.
     */
    function drupal_add_html_head($data = NULL) {
      $stored_head = &drupal_static(__FUNCTION__, '');
    
      if (!is_null($data)) {
        $stored_head .= $data . "\n";
      }
      return $stored_head;
    }
    
    /**
     * Retrieve output to be displayed in the head tag of the HTML page.
     */
    function drupal_get_html_head() {
      $output = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />\n";
      return $output . drupal_add_html_head();
    }
    
    /**
     * Reset the static variable which holds the aliases mapped for this request.
     */
    function drupal_clear_path_cache() {
      drupal_lookup_path('wipe');
    }
    
    /**
     * Add a feed URL for the current page.
     *
     * This function can be called as long the HTML header hasn't been sent.
     *
     * @param $url
     *   A url for the feed.
     * @param $title
     *   The title of the feed.
     */
    function drupal_add_feed($url = NULL, $title = '') {
      $stored_feed_links = &drupal_static(__FUNCTION__, array());
    
      if (!is_null($url) && !isset($stored_feed_links[$url])) {
        $stored_feed_links[$url] = theme('feed_icon', $url, $title);
    
        drupal_add_link(array('rel' => 'alternate',
                              'type' => 'application/rss+xml',
                              'title' => $title,
                              'href' => $url));
      }
      return $stored_feed_links;
    }
    
    /**
     * Get the feed URLs for the current page.
     *
     * @param $delimiter
     *   A delimiter to split feeds by.
     */
    function drupal_get_feeds($delimiter = "\n") {
      $feeds = drupal_add_feed();
      return implode($feeds, $delimiter);
    }
    
    /**
     * @name HTTP handling
     * @{
     * Functions to properly handle HTTP responses.
     */
    
    /**
     * Parse an array into a valid urlencoded query string.
     *
     * @param $query
     *   The array to be processed e.g. $_GET.
     * @param $exclude
     *   The array filled with keys to be excluded. Use parent[child] to exclude
     *   nested items.
     * @param $parent
     *   Should not be passed, only used in recursive calls.
     * @return
     *   An urlencoded string which can be appended to/as the URL query string.
     */
    function drupal_query_string_encode($query, $exclude = array(), $parent = '') {
      $params = array();
    
      foreach ($query as $key => $value) {
        $key = rawurlencode($key);
        if ($parent) {
          $key = $parent . '[' . $key . ']';
        }
    
        if (in_array($key, $exclude)) {
          continue;
        }
    
        if (is_array($value)) {
          $params[] = drupal_query_string_encode($value, $exclude, $key);
        }
        else {
          $params[] = $key . '=' . rawurlencode($value);
        }
      }
    
      return implode('&', $params);
    }
    
    /**
     * Prepare a destination query string for use in combination with drupal_goto().
     *
     * Used to direct the user back to the referring page after completing a form.
     * By default the current URL is returned. If a destination exists in the
     * previous request, that destination is returned. As such, a destination can
     * persist across multiple pages.
     *
     * @see drupal_goto()
     */
    function drupal_get_destination() {
      if (isset($_GET['destination'])) {
        return 'destination=' . urlencode($_GET['destination']);
      }
      else {
        // Use $_GET here to retrieve the original path in source form.
        $path = isset($_GET['q']) ? $_GET['q'] : '';
        $query = drupal_query_string_encode($_GET, array('q'));
        if ($query != '') {
          $path .= '?' . $query;
        }
        return 'destination=' . urlencode($path);
      }
    }
    
    /**
     * Send the user to a different Drupal page.
     *
     * This issues an on-site HTTP redirect. The function makes sure the redirected
     * URL is formatted correctly.
     *
     * Usually the redirected URL is constructed from this function's input
     * parameters. However you may override that behavior by setting a
     * destination in either the $_REQUEST-array (i.e. by using
     * the query string of an URI) This is used to direct the user back to
     * the proper page after completing a form. For example, after editing
     * a post on the 'admin/content'-page or after having logged on using the
     * 'user login'-block in a sidebar. The function drupal_get_destination()
     * can be used to help set the destination URL.
     *
     * Drupal will ensure that messages set by drupal_set_message() and other
     * session data are written to the database before the user is redirected.
     *
     * This function ends the request; use it instead of a return in your menu callback.
     *
     * @param $path
     *   A Drupal path or a full URL.
     * @param $query
     *   A query string component, if any.
     * @param $fragment
     *   A destination fragment identifier (named anchor).
     * @param $http_response_code
     *   Valid values for an actual "goto" as per RFC 2616 section 10.3 are:
     *   - 301 Moved Permanently (the recommended value for most redirects)
     *   - 302 Found (default in Drupal and PHP, sometimes used for spamming search
     *         engines)
     *   - 303 See Other
     *   - 304 Not Modified
     *   - 305 Use Proxy
     *   - 307 Temporary Redirect (alternative to "503 Site Down for Maintenance")
     *   Note: Other values are defined by RFC 2616, but are rarely used and poorly
     *   supported.
     * @see drupal_get_destination()
     */
    function drupal_goto($path = '', $query = NULL, $fragment = NULL, $http_response_code = 302) {
      if (isset($_GET['destination'])) {
        extract(parse_url(urldecode($_GET['destination'])));
      }
    
      $args = array(
        'path' => &$path,
        'query' => &$query,
        'fragment' => &$fragment,
        'http_response_code' => &$http_response_code,
      );
      drupal_alter('drupal_goto', $args);
    
      $url = url($path, array('query' => $query, 'fragment' => $fragment, 'absolute' => TRUE));
    
      // Allow modules to react to the end of the page request before redirecting.
      // We do not want this while running update.php.
      if (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update') {
        module_invoke_all('exit', $url);
      }
    
      // Commit the session, if necessary. We need all session data written to the
      // database before redirecting.
      drupal_session_commit();
    
      header('Location: ' . $url, TRUE, $http_response_code);
    
      // The "Location" header sends a redirect status code to the HTTP daemon. In
      // some cases this can be wrong, so we make sure none of the code below the
      // drupal_goto() call gets executed upon redirection.
      exit();
    }
    
    /**
     * Generates a site offline message.
     */
    function drupal_site_offline() {
      drupal_maintenance_theme();
      drupal_set_header('503 Service unavailable');
      drupal_set_title(t('Site under maintenance'));
      print theme('maintenance_page', filter_xss_admin(variable_get('maintenance_mode_message',
        t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => variable_get('site_name', 'Drupal'))))));
    }
    
    /**
     * Generates a 404 error if the request can not be handled.
     */
    function drupal_not_found() {
      drupal_set_header('404 Not Found');
    
      watchdog('page not found', check_plain($_GET['q']), NULL, WATCHDOG_WARNING);
    
      // Keep old path for reference, and to allow forms to redirect to it.
      if (!isset($_GET['destination'])) {
        $_GET['destination'] = $_GET['q'];
      }
    
      $path = drupal_get_normal_path(variable_get('site_404', ''));
      if ($path && $path != $_GET['q']) {
        // Custom 404 handler. Set the active item in case there are tabs to
        // display, or other dependencies on the path.
        menu_set_active_item($path);
        $return = menu_execute_active_handler($path);
      }
    
      if (empty($return) || $return == MENU_NOT_FOUND || $return == MENU_ACCESS_DENIED) {
        // Standard 404 handler.
        drupal_set_title(t('Page not found'));
        $return = t('The requested page could not be found.');
      }
    
      drupal_set_page_content($return);
      $page = element_info('page');
      print drupal_render_page($page);
    }
    
    /**
     * Generates a 403 error if the request is not allowed.
     */
    function drupal_access_denied() {
      drupal_set_header('403 Forbidden');
      watchdog('access denied', check_plain($_GET['q']), NULL, WATCHDOG_WARNING);
    
      // Keep old path for reference, and to allow forms to redirect to it.
      if (!isset($_GET['destination'])) {
        $_GET['destination'] = $_GET['q'];
      }
    
      $path = drupal_get_normal_path(variable_get('site_403', ''));
      if ($path && $path != $_GET['q']) {
        // Custom 403 handler. Set the active item in case there are tabs to
        // display or other dependencies on the path.
        menu_set_active_item($path);
        $return = menu_execute_active_handler($path);
      }
    
      if (empty($return) || $return == MENU_NOT_FOUND || $return == MENU_ACCESS_DENIED) {
        // Standard 403 handler.
        drupal_set_title(t('Access denied'));
        $return = t('You are not authorized to access this page.');
      }
    
      print drupal_render_page($return);
    }
    
    /**
     * Perform an HTTP request.
     *
     * This is a flexible and powerful HTTP client implementation. Correctly
     * handles GET, POST, PUT or any other HTTP requests. Handles redirects.
     *
     * @param $url
     *   A string containing a fully qualified URI.
     * @param $options
     *   (optional) An array which can have one or more of following keys:
     *   - headers
     *       An array containing request headers to send as name/value pairs.
     *   - method
     *       A string containing the request method. Defaults to 'GET'.
     *   - data
     *       A string containing the request body. Defaults to NULL.
     *   - max_redirects
     *       An integer representing how many times a redirect may be followed.
     *       Defaults to 3.
     *   - timeout
     *       A float representing the maximum number of seconds the function call
     *       may take. The default is 30 seconds. If a timeout occurs, the error
     *       code is set to the HTTP_REQUEST_TIMEOUT constant.
     * @return
     *   An object which can have one or more of the following parameters:
     *   - request
     *       A string containing the request body that was sent.
     *   - code
     *       An integer containing the response status code, or the error code if
     *       an error occurred.
     *   - protocol
     *       The response protocol (e.g. HTTP/1.1 or HTTP/1.0).
     *   - status_message
     *       The status message from the response, if a response was received.
     *   - redirect_code
     *       If redirected, an integer containing the initial response status code.
     *   - redirect_url
     *       If redirected, a string containing the redirection location.
     *   - error
     *       If an error occurred, the error message. Otherwise not set.
     *   - headers
     *       An array containing the response headers as name/value pairs.
     *   - data
     *       A string containing the response body that was received.
     */
    function drupal_http_request($url, array $options = array()) {
      global $db_prefix;
    
      $result = new stdClass();
    
      // Parse the URL and make sure we can handle the schema.
      $uri = @parse_url($url);
    
      if ($uri == FALSE) {
        $result->error = 'unable to parse URL';
        $result->code = -1001;
        return $result;
      }
    
      if (!isset($uri['scheme'])) {
        $result->error = 'missing schema';
        $result->code = -1002;
        return $result;
      }
    
      timer_start(__FUNCTION__);
    
      // Merge the default options.
      $options += array(
        'headers' => array(),
        'method' => 'GET',
        'data' => NULL,
        'max_redirects' => 3,
        'timeout' => 30,
      );
    
      switch ($uri['scheme']) {
        case 'http':
          $port = isset($uri['port']) ? $uri['port'] : 80;
          $host = $uri['host'] . ($port != 80 ? ':' . $port : '');
          $fp = @fsockopen($uri['host'], $port, $errno, $errstr, $options['timeout']);
          break;
        case 'https':
          // Note: Only works when PHP is compiled with OpenSSL support.
          $port = isset($uri['port']) ? $uri['port'] : 443;
          $host = $uri['host'] . ($port != 443 ? ':' . $port : '');
          $fp = @fsockopen('ssl://' . $uri['host'], $port, $errno, $errstr, $options['timeout']);
          break;
        default:
          $result->error = 'invalid schema ' . $uri['scheme'];
          $result->code = -1003;
          return $result;
      }
    
      // Make sure the socket opened properly.
      if (!$fp) {
        // When a network error occurs, we use a negative number so it does not
        // clash with the HTTP status codes.
        $result->code = -$errno;
        $result->error = trim($errstr);
    
        // Mark that this request failed. This will trigger a check of the web
        // server's ability to make outgoing HTTP requests the next time that
        // requirements checking is performed.
        // @see system_requirements()
        variable_set('drupal_http_request_fails', TRUE);
    
        return $result;
      }
    
      // Construct the path to act on.
      $path = isset($uri['path']) ? $uri['path'] : '/';
      if (isset($uri['query'])) {
        $path .= '?' . $uri['query'];
      }
    
      // Merge the default headers.
      $options['headers'] += array(
        'User-Agent' => 'Drupal (+http://drupal.org/)',
      );
    
      // RFC 2616: "non-standard ports MUST, default ports MAY be included".
      // We don't add the standard port to prevent from breaking rewrite rules
      // checking the host that do not take into account the port number.
      $options['headers']['Host'] = $host;
    
      // Only add Content-Length if we actually have any content or if it is a POST
      // or PUT request. Some non-standard servers get confused by Content-Length in
      // at least HEAD/GET requests, and Squid always requires Content-Length in
      // POST/PUT requests.
      $content_length = strlen($options['data']);
      if ($content_length > 0 || $options['method'] == 'POST' || $options['method'] == 'PUT') {
        $options['headers']['Content-Length'] = $content_length;
      }
    
      // If the server URL has a user then attempt to use basic authentication.
      if (isset($uri['user'])) {
        $options['headers']['Authorization'] = 'Basic ' . base64_encode($uri['user'] . (!empty($uri['pass']) ? ":" . $uri['pass'] : ''));
      }
    
      // If the database prefix is being used by SimpleTest to run the tests in a copied
      // database then set the user-agent header to the database prefix so that any
      // calls to other Drupal pages will run the SimpleTest prefixed database. The
      // user-agent is used to ensure that multiple testing sessions running at the
      // same time won't interfere with each other as they would if the database
      // prefix were stored statically in a file or database variable.
      if (is_string($db_prefix) && preg_match("/simpletest\d+/", $db_prefix, $matches)) {
        $options['headers']['User-Agent'] = drupal_generate_test_ua($matches[0]);
      }
    
      $request = $options['method'] . ' ' . $path . " HTTP/1.0\r\n";
      foreach ($options['headers'] as $name => $value) {
        $request .= $name . ': ' . trim($value) . "\r\n";
      }
      $request .= "\r\n" . $options['data'];
      $result->request = $request;
    
      fwrite($fp, $request);
    
      // Fetch response.
      $response = '';
      while (!feof($fp)) {
        // Calculate how much time is left of the original timeout value.
        $timeout = $options['timeout'] - timer_read(__FUNCTION__) / 1000;
        if ($timeout <= 0) {
          $result->code = HTTP_REQUEST_TIMEOUT;
          $result->error = 'request timed out';
          return $result;
        }
        stream_set_timeout($fp, floor($timeout), floor(1000000 * fmod($timeout, 1)));
        $response .= fread($fp, 1024);
      }
      fclose($fp);
    
      // Parse response headers from the response body.
      list($response, $result->data) = explode("\r\n\r\n", $response, 2);
      $response = preg_split("/\r\n|\n|\r/", $response);
    
      // Parse the response status line.
      list($protocol, $code, $status_message) = explode(' ', trim(array_shift($response)), 3);
      $result->protocol = $protocol;
      $result->status_message = $status_message;
    
      $result->headers = array();
    
      // Parse the response headers.
      while ($line = trim(array_shift($response))) {
        list($header, $value) = explode(':', $line, 2);
        if (isset($result->headers[$header]) && $header == 'Set-Cookie') {
          // RFC 2109: the Set-Cookie response header comprises the token Set-
          // Cookie:, followed by a comma-separated list of one or more cookies.
          $result->headers[$header] .= ',' . trim($value);
        }
        else {
          $result->headers[$header] = trim($value);
        }
      }
    
      $responses = array(
        100 => 'Continue',
        101 => 'Switching Protocols',
        200 => 'OK',
        201 => 'Created',
        202 => 'Accepted',
        203 => 'Non-Authoritative Information',
        204 => 'No Content',
        205 => 'Reset Content',
        206 => 'Partial Content',
        300 => 'Multiple Choices',
        301 => 'Moved Permanently',
        302 => 'Found',
        303 => 'See Other',
        304 => 'Not Modified',
        305 => 'Use Proxy',
        307 => 'Temporary Redirect',
        400 => 'Bad Request',
        401 => 'Unauthorized',
        402 => 'Payment Required',
        403 => 'Forbidden',
        404 => 'Not Found',
        405 => 'Method Not Allowed',
        406 => 'Not Acceptable',
        407 => 'Proxy Authentication Required',
        408 => 'Request Time-out',
        409 => 'Conflict',
        410 => 'Gone',
        411 => 'Length Required',
        412 => 'Precondition Failed',
        413 => 'Request Entity Too Large',
        414 => 'Request-URI Too Large',
        415 => 'Unsupported Media Type',
        416 => 'Requested range not satisfiable',
        417 => 'Expectation Failed',
        500 => 'Internal Server Error',
        501 => 'Not Implemented',
        502 => 'Bad Gateway',
        503 => 'Service Unavailable',
        504 => 'Gateway Time-out',
        505 => 'HTTP Version not supported',
      );
      // RFC 2616 states that all unknown HTTP codes must be treated the same as the
      // base code in their class.
      if (!isset($responses[$code])) {
        $code = floor($code / 100) * 100;
      }
      $result->code = $code;
    
      switch ($code) {
        case 200: // OK
        case 304: // Not modified
          break;
        case 301: // Moved permanently
        case 302: // Moved temporarily
        case 307: // Moved temporarily
          $location = $result->headers['Location'];
          $options['timeout'] -= timer_read(__FUNCTION__) / 1000;
          if ($options['timeout'] <= 0) {
            $result->code = HTTP_REQUEST_TIMEOUT;
            $result->error = 'request timed out';
          }
          elseif ($options['max_redirects']) {
            // Redirect to the new location.
            $options['max_redirects']--;
            $result = drupal_http_request($location, $options);
            $result->redirect_code = $code;
          }
          $result->redirect_url = $location;
          break;
        default:
          $result->error = $status_message;
      }
    
      return $result;
    }
    /**
     * @} End of "HTTP handling".
     */
    
    /**
     * Custom PHP error handler.
     *
     * @param $error_level
     *   The level of the error raised.
     * @param $message
     *   The error message.
     * @param $filename
     *   The filename that the error was raised in.
     * @param $line
     *   The line number the error was raised at.
     * @param $context
     *   An array that points to the active symbol table at the point the error occurred.
     */
    function _drupal_error_handler($error_level, $message, $filename, $line, $context) {
      if ($error_level & error_reporting()) {
        // All these constants are documented at http://php.net/manual/en/errorfunc.constants.php
        $types = array(
          E_ERROR => 'Error',
          E_WARNING => 'Warning',
          E_PARSE => 'Parse error',
          E_NOTICE => 'Notice',
          E_CORE_ERROR => 'Core error',
          E_CORE_WARNING => 'Core warning',
          E_COMPILE_ERROR => 'Compile error',
          E_COMPILE_WARNING => 'Compile warning',
          E_USER_ERROR => 'User error',
          E_USER_WARNING => 'User warning',
          E_USER_NOTICE => 'User notice',
          E_STRICT => 'Strict warning',
          E_RECOVERABLE_ERROR => 'Recoverable fatal error'
        );
        $caller = _drupal_get_last_caller(debug_backtrace());
    
        // We treat recoverable errors as fatal.
        _drupal_log_error(array(
          '%type' => isset($types[$error_level]) ? $types[$error_level] : 'Unknown error',
          '%message' => $message,
          '%function' => $caller['function'],
          '%file' => $caller['file'],
          '%line' => $caller['line'],
        ), $error_level == E_RECOVERABLE_ERROR);
      }
    }
    
    /**
     * Custom PHP exception handler.
     *
     * Uncaught exceptions are those not enclosed in a try/catch block. They are
     * always fatal: the execution of the script will stop as soon as the exception
     * handler exits.
     *
     * @param $exception
     *   The exception object that was thrown.
     */
    function _drupal_exception_handler($exception) {
      // Log the message to the watchdog and return an error page to the user.
      _drupal_log_error(_drupal_decode_exception($exception), TRUE);
    }
    
    /**
     * Decode an exception, especially to retrive the correct caller.
     *
     * @param $exception
     *   The exception object that was thrown.
     * @return An error in the format expected by _drupal_log_error().
     */
    function _drupal_decode_exception($exception) {
      $message = $exception->getMessage();
    
      $backtrace = $exception->getTrace();
      // Add the line throwing the exception to the backtrace.
      array_unshift($backtrace, array('line' => $exception->getLine(), 'file' => $exception->getFile()));
    
      // For PDOException errors, we try to return the initial caller,
      // skipping internal functions of the database layer.
      if ($exception instanceof PDOException) {
        // The first element in the stack is the call, the second element gives us the caller.
        // We skip calls that occurred in one of the classes of the database layer
        // or in one of its global functions.
        $db_functions = array('db_query',  'db_query_range', 'update_sql');
        while (!empty($backtrace[1]) && ($caller = $backtrace[1]) &&
            ((isset($caller['class']) && (strpos($caller['class'], 'Query') !== FALSE || strpos($caller['class'], 'Database') !== FALSE || strpos($caller['class'], 'PDO') !== FALSE)) ||
            in_array($caller['function'], $db_functions))) {
          // We remove that call.
          array_shift($backtrace);
        }
        if (isset($exception->query_string, $exception->args)) {
          $message .= ": " . $exception->query_string . "; " . print_r($exception->args, TRUE);
        }
      }
      $caller = _drupal_get_last_caller($backtrace);
    
      return array(
        '%type' => get_class($exception),
        '%message' => $message,
        '%function' => $caller['function'],
        '%file' => $caller['file'],
        '%line' => $caller['line'],
      );
    }
    
    /**
     * Log a PHP error or exception, display an error page in fatal cases.
     *
     * @param $error
     *   An array with the following keys: %type, %message, %function, %file, %line.
     * @param $fatal
     *   TRUE if the error is fatal.
     */
    function _drupal_log_error($error, $fatal = FALSE) {
      // Initialize a maintenance theme if the boostrap was not complete.
      // Do it early because drupal_set_message() triggers a drupal_theme_initialize().
      if ($fatal && (drupal_get_bootstrap_phase() != DRUPAL_BOOTSTRAP_FULL)) {
        unset($GLOBALS['theme']);
        if (!defined('MAINTENANCE_MODE')) {
          define('MAINTENANCE_MODE', 'error');
        }
        drupal_maintenance_theme();
      }
    
      // When running inside the testing framework, we relay the errors
      // to the tested site by the way of HTTP headers.
      if (isset($_SERVER['HTTP_USER_AGENT']) && preg_match("/^simpletest\d+;/", $_SERVER['HTTP_USER_AGENT']) && !headers_sent() && (!defined('SIMPLETEST_COLLECT_ERRORS') || SIMPLETEST_COLLECT_ERRORS)) {
        // $number does not use drupal_static as it should not be reset
        // as it uniquely identifies each PHP error.
        static $number = 0;
        $assertion = array(
          $error['%message'],
          $error['%type'],
          array(
            'function' => $error['%function'],
            'file' => $error['%file'],
            'line' => $error['%line'],
          ),
        );
        header('X-Drupal-Assertion-' . $number . ': ' . rawurlencode(serialize($assertion)));
        $number++;
      }
    
      try {
        watchdog('php', '%type: %message in %function (line %line of %file).', $error, WATCHDOG_ERROR);
      }
      catch (Exception $e) {
        // Ignore any additional watchdog exception, as that probably means
        // that the database was not initialized correctly.
      }
    
      if ($fatal) {
        drupal_set_header('500 Service unavailable (with message)');
      }
    
      if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest') {
        if ($fatal) {
          // When called from JavaScript, simply output the error message.
          print t('%type: %message in %function (line %line of %file).', $error);
          exit;
        }
      }
      else {
        // Display the message if the current error reporting level allows this type
        // of message to be displayed, and unconditionnaly in update.php.
        $error_level = variable_get('error_level', ERROR_REPORTING_DISPLAY_ALL);
        $display_error = $error_level == ERROR_REPORTING_DISPLAY_ALL || ($error_level == ERROR_REPORTING_DISPLAY_SOME && $error['%type'] != 'Notice');
        if ($display_error || (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'update')) {
          $class = 'error';
    
          // If error type is 'User notice' then treat it as debug information
          // instead of an error message, see dd().
          if ($error['%type'] == 'User notice') {
            $error['%type'] = 'Debug';
            $class = 'status';
          }
    
          drupal_set_message(t('%type: %message in %function (line %line of %file).', $error), $class);
        }
    
        if ($fatal) {
          drupal_set_title(t('Error'));
          // We fallback to a maintenance page at this point, because the page generation
          // itself can generate errors.
          print theme('maintenance_page', t('The website encountered an unexpected error. Please try again later.'));
          exit;
        }
      }
    }
    
    /**
     * Gets the last caller from a backtrace.
     *
     * @param $backtrace
     *   A standard PHP backtrace.
     * @return
     *   An associative array with keys 'file', 'line' and 'function'.
     */
    function _drupal_get_last_caller($backtrace) {
      // Errors that occur inside PHP internal functions do not generate
      // information about file and line. Ignore black listed functions.
      $blacklist = array('debug');
      while (($backtrace && !isset($backtrace[0]['line'])) ||
             (isset($backtrace[1]['function']) && in_array($backtrace[1]['function'], $blacklist))) {
        array_shift($backtrace);
      }
    
      // The first trace is the call itself.
      // It gives us the line and the file of the last call.
      $call = $backtrace[0];
    
      // The second call give us the function where the call originated.
      if (isset($backtrace[1])) {
        if (isset($backtrace[1]['class'])) {
          $call['function'] = $backtrace[1]['class'] . $backtrace[1]['type'] . $backtrace[1]['function'] . '()';
        }
        else {
          $call['function'] = $backtrace[1]['function'] . '()';
        }
      }
      else {
        $call['function'] = 'main()';
      }
      return $call;
    }
    
    function _fix_gpc_magic(&$item) {
      if (is_array($item)) {
        array_walk($item, '_fix_gpc_magic');
      }
      else {
        $item = stripslashes($item);
      }
    }
    
    /**
     * Helper function to strip slashes from $_FILES skipping over the tmp_name keys
     * since PHP generates single backslashes for file paths on Windows systems.
     *
     * tmp_name does not have backslashes added see
     * http://php.net/manual/en/features.file-upload.php#42280
     */
    function _fix_gpc_magic_files(&$item, $key) {
      if ($key != 'tmp_name') {
        if (is_array($item)) {
          array_walk($item, '_fix_gpc_magic_files');
        }
        else {
          $item = stripslashes($item);
        }
      }
    }
    
    /**
     * Fix double-escaping problems caused by "magic quotes" in some PHP installations.
     */
    function fix_gpc_magic() {
      $fixed = &drupal_static(__FUNCTION__, FALSE);
      if (!$fixed && ini_get('magic_quotes_gpc')) {
        array_walk($_GET, '_fix_gpc_magic');
        array_walk($_POST, '_fix_gpc_magic');
        array_walk($_COOKIE, '_fix_gpc_magic');
        array_walk($_REQUEST, '_fix_gpc_magic');
        array_walk($_FILES, '_fix_gpc_magic_files');
        $fixed = TRUE;
      }
    }
    
    /**
     * Translate strings to the page language or a given language.
     *
     * Human-readable text that will be displayed somewhere within a page should
     * be run through the t() function.
     *
     * Examples:
     * @code
     *   if (!$info || !$info['extension']) {
     *     form_set_error('picture_upload', t('The uploaded file was not an image.'));
     *   }
     *
     *   $form['submit'] = array(
     *     '#type' => 'submit',
     *     '#value' => t('Log in'),
     *   );
     * @endcode
     *
     * Any text within t() can be extracted by translators and changed into
     * the equivalent text in their native language.
     *
     * Special variables called "placeholders" are used to signal dynamic
     * information in a string which should not be translated. Placeholders
     * can also be used for text that may change from time to time (such as
     * link paths) to be changed without requiring updates to translations.
     *
     * For example:
     * @code
     *   $output = t('There are currently %members and %visitors online.', array(
     *     '%members' => format_plural($total_users, '1 user', '@count users'),
     *     '%visitors' => format_plural($guests->count, '1 guest', '@count guests')));
     * @endcode
     *
     * There are three styles of placeholders:
     * - !variable, which indicates that the text should be inserted as-is. This is
     *   useful for inserting variables into things like e-mail.
     *   @code
     *     $message[] = t("If you don't want to receive such e-mails, you can change your settings at !url.", array('!url' => url("user/$account->uid", array('absolute' => TRUE))));
     *   @endcode
     *
     * - @variable, which indicates that the text should be run through
     *   check_plain, to escape HTML characters. Use this for any output that's
     *   displayed within a Drupal page.
     *   @code
     *     drupal_set_title($title = t("@name's blog", array('@name' => $account->name)), PASS_THROUGH);
     *   @endcode
     *
     * - %variable, which indicates that the string should be HTML escaped and
     *   highlighted with theme_placeholder() which shows up by default as
     *   <em>emphasized</em>.
     *   @code
     *     $message = t('%name-from sent %name-to an e-mail.', array('%name-from' => $user->name, '%name-to' => $account->name));
     *   @endcode
     *
     * When using t(), try to put entire sentences and strings in one t() call.
     * This makes it easier for translators, as it provides context as to what
     * each word refers to. HTML markup within translation strings is allowed, but
     * should be avoided if possible. The exception are embedded links; link
     * titles add a context for translators, so should be kept in the main string.
     *
     * Here is an example of incorrect usage of t():
     * @code
     *   $output .= t('<p>Go to the @contact-page.</p>', array('@contact-page' => l(t('contact page'), 'contact')));
     * @endcode
     *
     * Here is an example of t() used correctly:
     * @code
     *   $output .= '<p>' . t('Go to the <a href="@contact-page">contact page</a>.', array('@contact-page' => url('contact'))) . '</p>';
     * @endcode
     *
     * Avoid escaping quotation marks wherever possible.
     *
     * Incorrect:
     * @code
     *   $output .= t('Don\'t click me.');
     * @endcode
     *
     * Correct:
     * @code
     *   $output .= t("Don't click me.");
     * @endcode
     *
     * Because t() is designed for handling code-based strings, in almost all
     * cases, the actual string and not a variable must be passed through t().
     *
     * Extraction of translations is done based on the strings contained in t()
     * calls. If a variable is passed through t(), the content of the variable
     * cannot be extracted from the file for translation.
     *
     * Incorrect:
     * @code
     *   $message = 'An error occurred.';
     *   drupal_set_message(t($message), 'error');
     *   $output .= t($message);
     * @endcode
     *
     * Correct:
     * @code
     *   $message = t('An error occurred.');
     *   drupal_set_message($message, 'error');
     *   $output .= $message;
     * @endcode
     *
     * The only case in which variables can be passed safely through t() is when
     * code-based versions of the same strings will be passed through t() (or
     * otherwise extracted) elsewhere.
     *
     * In some cases, modules may include strings in code that can't use t()
     * calls. For example, a module may use an external PHP application that
     * produces strings that are loaded into variables in Drupal for output.
     * In these cases, module authors may include a dummy file that passes the
     * relevant strings through t(). This approach will allow the strings to be
     * extracted.
     *
     * Sample external (non-Drupal) code:
     * @code
     *   class Time {
     *     public $yesterday = 'Yesterday';
     *     public $today = 'Today';
     *     public $tomorrow = 'Tomorrow';
     *   }
     * @endcode
     *
     * Sample dummy file.
     * @code
     *   // Dummy function included in example.potx.inc.
     *   function example_potx() {
     *     $strings = array(
     *       t('Yesterday'),
     *       t('Today'),
     *       t('Tomorrow'),
     *     );
     *     // No return value needed, since this is a dummy function.
     *   }
     * @endcode
     *
     * Having passed strings through t() in a dummy function, it is then
     * okay to pass variables through t().
     *
     * Correct (if a dummy file was used):
     * @code
     *   $time = new Time();
     *   $output .= t($time->today);
     * @endcode
     *
     * However tempting it is, custom data from user input or other non-code
     * sources should not be passed through t(). Doing so leads to the following
     * problems and errors:
     *  - The t() system doesn't support updates to existing strings. When user
     *    data is updated, the next time it's passed through t() a new record is
     *    created instead of an update. The database bloats over time and any
     *    existing translations are orphaned with each update.
     *  - The t() system assumes any data it receives is in English. User data may
     *    be in another language, producing translation errors.
     *  - The "Built-in interface" text group in the locale system is used to
     *    produce translations for storage in .po files. When non-code strings are
     *    passed through t(), they are added to this text group, which is rendered
     *    inaccurate since it is a mix of actual interface strings and various user
     *    input strings of uncertain origin.
     *
     * Incorrect:
     * @code
     *   $item = item_load();
     *   $output .= check_plain(t($item['title']));
     * @endcode
     *
     * Instead, translation of these data can be done through the locale system,
     * either directly or through helper functions provided by contributed
     * modules.
     * @see hook_locale()
     *
     * During installation, st() is used in place of t(). Code that may be called
     * during installation or during normal operation should use the get_t()
     * helper function.
     * @see st()
     * @see get_t()
     *
     * @param $string
     *   A string containing the English string to translate.
     * @param $args
     *   An associative array of replacements to make after translation. Incidences
     *   of any key in this array are replaced with the corresponding value. Based
     *   on the first character of the key, the value is escaped and/or themed:
     *    - !variable: inserted as is
     *    - @variable: escape plain text to HTML (check_plain)
     *    - %variable: escape text and theme as a placeholder for user-submitted
     *      content (check_plain + theme_placeholder)
     * @param $options
     *   An associative array of additional options, with the following keys:
     *     - 'langcode' (default to the current language) The language code to
     *       translate to a language other than what is used to display the page.
     *     - 'context' (default to the empty context) The context the source string
     *       belongs to.
     * @return
     *   The translated string.
     */
    function t($string, array $args = array(), array $options = array()) {
      global $language;
      static $custom_strings;
    
      // Merge in default.
      if (empty($options['langcode'])) {
        $options['langcode'] = isset($language->language) ? $language->language : 'en';
      }
      if (empty($options['context'])) {
        $options['context'] = '';
      }
    
      // First, check for an array of customized strings. If present, use the array
      // *instead of* database lookups. This is a high performance way to provide a
      // handful of string replacements. See settings.php for examples.
      // Cache the $custom_strings variable to improve performance.
      if (!isset($custom_strings[$options['langcode']])) {
        $custom_strings[$options['langcode']] = variable_get('locale_custom_strings_' . $options['langcode'], array());
      }
      // Custom strings work for English too, even if locale module is disabled.
      if (isset($custom_strings[$options['langcode']][$options['context']][$string])) {
        $string = $custom_strings[$options['langcode']][$options['context']][$string];
      }
      // Translate with locale module if enabled.
      // We don't use function_exists() here, because it breaks the testing
      // framework if the locale module is enabled in the parent site (we cannot
      // unload functions in PHP).
      elseif (function_exists('locale') && $options['langcode'] != 'en') {
        $string = locale($string, $options['context'], $options['langcode']);
      }
      if (empty($args)) {
        return $string;
      }
      else {
        // Transform arguments before inserting them.
        foreach ($args as $key => $value) {
          switch ($key[0]) {
            case '@':
              // Escaped only.
              $args[$key] = check_plain($value);
              break;
    
            case '%':
            default:
              // Escaped and placeholder.
              $args[$key] = theme('placeholder', $value);
              break;
    
            case '!':
              // Pass-through.
          }
        }
        return strtr($string, $args);
      }
    }
    
    /**
     * @defgroup validation Input validation
     * @{
     * Functions to validate user input.
     */
    
    /**
     * Verify the syntax of the given e-mail address.
     *
     * Empty e-mail addresses are allowed. See RFC 2822 for details.
     *
     * @param $mail
     *   A string containing an e-mail address.
     * @return
     *   TRUE if the address is in a valid format.
     */
    function valid_email_address($mail) {
      return (bool)filter_var($mail, FILTER_VALIDATE_EMAIL);
    }
    
    /**
     * Verify the syntax of the given URL.
     *
     * This function should only be used on actual URLs. It should not be used for
     * Drupal menu paths, which can contain arbitrary characters.
     * Valid values per RFC 3986.
     * @param $url
     *   The URL to verify.
     * @param $absolute
     *   Whether the URL is absolute (beginning with a scheme such as "http:").
     * @return
     *   TRUE if the URL is in a valid format.
     */
    function valid_url($url, $absolute = FALSE) {
      if ($absolute) {
        return (bool)preg_match("
          /^                                                      # Start at the beginning of the text
          (?:ftp|https?):\/\/                                     # Look for ftp, http, or https schemes
          (?:                                                     # Userinfo (optional) which is typically
            (?:(?:[\w\.\-\+!$&'\(\)*\+,;=]|%[0-9a-f]{2})+:)*      # a username or a username and password
            (?:[\w\.\-\+%!$&'\(\)*\+,;=]|%[0-9a-f]{2})+@          # combination
          )?
          (?:
            (?:[a-z0-9\-\.]|%[0-9a-f]{2})+                        # A domain name or a IPv4 address
            |(?:\[(?:[0-9a-f]{0,4}:)*(?:[0-9a-f]{0,4})\])         # or a well formed IPv6 address
          )
          (?::[0-9]+)?                                            # Server port number (optional)
          (?:[\/|\?]
            (?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})   # The path and query (optional)
          *)?
        $/xi", $url);
      }
      else {
        return (bool)preg_match("/^(?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})+$/i", $url);
      }
    }
    
    /**
     * @} End of "defgroup validation".
     */
    
    /**
     * Register an event for the current visitor to the flood control mechanism.
     *
     * @param $name
     *   The name of an event.
     * @param $identifier
     *   Optional identifier (defaults to the current user's IP address).
     */
    function flood_register_event($name, $identifier = NULL) {
      if (!isset($identifier)) {
        $identifier = ip_address();
      }
      db_insert('flood')
        ->fields(array(
          'event' => $name,
          'identifier' => $identifier,
          'timestamp' => REQUEST_TIME,
        ))
        ->execute();
    }
    
    /**
     * Make the flood control mechanism forget about an event for the current visitor.
     *
     * @param $name
     *   The name of an event.
     * @param $identifier
     *   Optional identifier (defaults to the current user's IP address).
     */
    function flood_clear_event($name, $identifier = NULL) {
      if (!isset($identifier)) {
        $identifier = ip_address();
      }
      db_delete('flood')
        ->condition('event', $name)
        ->condition('identifier', $identifier)
        ->execute();
    }
    
    /**
     * Check if the current visitor is allowed to proceed with the specified event.
     *
     * The user is allowed to proceed if he did not trigger the specified event more
     * than $threshold times in the specified time window.
     *
     * @param $name
     *   The name of the event.
     * @param $threshold
     *   The maximum number of the specified event allowed per time window.
     * @param $window
     *   Optional number of seconds over which to look for events.  Defaults to
     *   3600 (1 hour).
     * @param $identifier
     *   Optional identifier (defaults to the current user's IP address).
     * @return
     *   True if the user did not exceed the hourly threshold. False otherwise.
     */
    function flood_is_allowed($name, $threshold, $window = 3600, $identifier = NULL) {
      if (!isset($identifier)) {
        $identifier = ip_address();
      }
      $number = db_query("SELECT COUNT(*) FROM {flood} WHERE event = :event AND identifier = :identifier AND timestamp > :timestamp", array(
        ':event' => $name,
        ':identifier' => $identifier,
        ':timestamp' => REQUEST_TIME - $window))
        ->fetchField();
      return ($number < $threshold);
    }
    
    function check_file($filename) {
      return is_uploaded_file($filename);
    }
    
    /**
     * @defgroup sanitization Sanitization functions
     * @{
     * Functions to sanitize values.
     */
    
    /**
     * Prepare a URL for use in an HTML attribute. Strips harmful protocols.
     */
    function check_url($uri) {
      return filter_xss_bad_protocol($uri, FALSE);
    }
    
    /**
     * Very permissive XSS/HTML filter for admin-only use.
     *
     * Use only for fields where it is impractical to use the
     * whole filter system, but where some (mainly inline) mark-up
     * is desired (so check_plain() is not acceptable).
     *
     * Allows all tags that can be used inside an HTML body, save
     * for scripts and styles.
     */
    function filter_xss_admin($string) {
      return filter_xss($string, array('a', 'abbr', 'acronym', 'address', 'b', 'bdo', 'big', 'blockquote', 'br', 'caption', 'cite', 'code', 'col', 'colgroup', 'dd', 'del', 'dfn', 'div', 'dl', 'dt', 'em', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'img', 'ins', 'kbd', 'li', 'ol', 'p', 'pre', 'q', 'samp', 'small', 'span', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'tt', 'ul', 'var'));
    }
    
    /**
     * Filter XSS.
     *
     * Based on kses by Ulf Harnhammar, see
     * http://sourceforge.net/projects/kses
     *
     * For examples of various XSS attacks, see:
     * http://ha.ckers.org/xss.html
     *
     * This code does four things:
     * - Removes characters and constructs that can trick browsers
     * - Makes sure all HTML entities are well-formed
     * - Makes sure all HTML tags and attributes are well-formed
     * - Makes sure no HTML tags contain URLs with a disallowed protocol (e.g. javascript:)
     *
     * @param $string
     *   The string with raw HTML in it. It will be stripped of everything that can cause
     *   an XSS attack.
     * @param $allowed_tags
     *   An array of allowed tags.
     */
    function filter_xss($string, $allowed_tags = array('a', 'em', 'strong', 'cite', 'blockquote', 'code', 'ul', 'ol', 'li', 'dl', 'dt', 'dd')) {
      // Only operate on valid UTF-8 strings. This is necessary to prevent cross
      // site scripting issues on Internet Explorer 6.
      if (!drupal_validate_utf8($string)) {
        return '';
      }
      // Store the text format
      _filter_xss_split($allowed_tags, TRUE);
      // Remove NULL characters (ignored by some browsers)
      $string = str_replace(chr(0), '', $string);
      // Remove Netscape 4 JS entities
      $string = preg_replace('%&\s*\{[^}]*(\}\s*;?|$)%', '', $string);
    
      // Defuse all HTML entities
      $string = str_replace('&', '&amp;', $string);
      // Change back only well-formed entities in our whitelist
      // Decimal numeric entities
      $string = preg_replace('/&amp;#([0-9]+;)/', '&#\1', $string);
      // Hexadecimal numeric entities
      $string = preg_replace('/&amp;#[Xx]0*((?:[0-9A-Fa-f]{2})+;)/', '&#x\1', $string);
      // Named entities
      $string = preg_replace('/&amp;([A-Za-z][A-Za-z0-9]*;)/', '&\1', $string);
    
      return preg_replace_callback('%
        (
        <(?=[^a-zA-Z!/])  # a lone <
        |                 # or
        <[^>]*(>|$)       # a string that starts with a <, up until the > or the end of the string
        |                 # or
        >                 # just a >
        )%x', '_filter_xss_split', $string);
    }
    
    /**
     * Processes an HTML tag.
     *
     * @param $m
     *   An array with various meaning depending on the value of $store.
     *   If $store is TRUE then the array contains the allowed tags.
     *   If $store is FALSE then the array has one element, the HTML tag to process.
     * @param $store
     *   Whether to store $m.
     * @return
     *   If the element isn't allowed, an empty string. Otherwise, the cleaned up
     *   version of the HTML element.
     */
    function _filter_xss_split($m, $store = FALSE) {
      static $allowed_html;
    
      if ($store) {
        $allowed_html = array_flip($m);
        return;
      }
    
      $string = $m[1];
    
      if (substr($string, 0, 1) != '<') {
        // We matched a lone ">" character
        return '&gt;';
      }
      elseif (strlen($string) == 1) {
        // We matched a lone "<" character
        return '&lt;';
      }
    
      if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9]+)([^>]*)>?$%', $string, $matches)) {
        // Seriously malformed
        return '';
      }
    
      $slash = trim($matches[1]);
      $elem = &$matches[2];
      $attrlist = &$matches[3];
    
      if (!isset($allowed_html[strtolower($elem)])) {
        // Disallowed HTML element
        return '';
      }
    
      if ($slash != '') {
        return "</$elem>";
      }
    
      // Is there a closing XHTML slash at the end of the attributes?
      $attrlist = preg_replace('%(\s?)/\s*$%', '\1', $attrlist, -1, $count);
      $xhtml_slash = $count ? ' /' : '';
    
      // Clean up attributes
      $attr2 = implode(' ', _filter_xss_attributes($attrlist));
      $attr2 = preg_replace('/[<>]/', '', $attr2);
      $attr2 = strlen($attr2) ? ' ' . $attr2 : '';
    
      return "<$elem$attr2$xhtml_slash>";
    }
    
    /**
     * Processes a string of HTML attributes.
     *
     * @return
     *   Cleaned up version of the HTML attributes.
     */
    function _filter_xss_attributes($attr) {
      $attrarr = array();
      $mode = 0;
      $attrname = '';
    
      while (strlen($attr) != 0) {
        // Was the last operation successful?
        $working = 0;
    
        switch ($mode) {
          case 0:
            // Attribute name, href for instance
            if (preg_match('/^([-a-zA-Z]+)/', $attr, $match)) {
              $attrname = strtolower($match[1]);
              $skip = ($attrname == 'style' || substr($attrname, 0, 2) == 'on');
              $working = $mode = 1;
              $attr = preg_replace('/^[-a-zA-Z]+/', '', $attr);
            }
            break;
    
          case 1:
            // Equals sign or valueless ("selected")
            if (preg_match('/^\s*=\s*/', $attr)) {
              $working = 1; $mode = 2;
              $attr = preg_replace('/^\s*=\s*/', '', $attr);
              break;
            }
    
            if (preg_match('/^\s+/', $attr)) {
              $working = 1; $mode = 0;
              if (!$skip) {
                $attrarr[] = $attrname;
              }
              $attr = preg_replace('/^\s+/', '', $attr);
            }
            break;
    
          case 2:
            // Attribute value, a URL after href= for instance
            if (preg_match('/^"([^"]*)"(\s+|$)/', $attr, $match)) {
              $thisval = filter_xss_bad_protocol($match[1]);
    
              if (!$skip) {
                $attrarr[] = "$attrname=\"$thisval\"";
              }
              $working = 1;
              $mode = 0;
              $attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr);
              break;
            }
    
            if (preg_match("/^'([^']*)'(\s+|$)/", $attr, $match)) {
              $thisval = filter_xss_bad_protocol($match[1]);
    
              if (!$skip) {
                $attrarr[] = "$attrname='$thisval'";
              }
              $working = 1; $mode = 0;
              $attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr);
              break;
            }
    
            if (preg_match("%^([^\s\"']+)(\s+|$)%", $attr, $match)) {
              $thisval = filter_xss_bad_protocol($match[1]);
    
              if (!$skip) {
                $attrarr[] = "$attrname=\"$thisval\"";
              }
              $working = 1; $mode = 0;
              $attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
            }
            break;
        }
    
        if ($working == 0) {
          // not well formed, remove and try again
          $attr = preg_replace('/
            ^
            (
            "[^"]*("|$)     # - a string that starts with a double quote, up until the next double quote or the end of the string
            |               # or
            \'[^\']*(\'|$)| # - a string that starts with a quote, up until the next quote or the end of the string
            |               # or
            \S              # - a non-whitespace character
            )*              # any number of the above three
            \s*             # any number of whitespaces
            /x', '', $attr);
          $mode = 0;
        }
      }
    
      // The attribute list ends with a valueless attribute like "selected".
      if ($mode == 1) {
        $attrarr[] = $attrname;
      }
      return $attrarr;
    }
    
    /**
     * Processes an HTML attribute value and ensures it does not contain an URL with a disallowed protocol (e.g. javascript:).
     *
     * @param $string
     *   The string with the attribute value.
     * @param $decode
     *   Whether to decode entities in the $string. Set to FALSE if the $string
     *   is in plain text, TRUE otherwise. Defaults to TRUE.
     * @return
     *   Cleaned up and HTML-escaped version of $string.
     */
    function filter_xss_bad_protocol($string, $decode = TRUE) {
      static $allowed_protocols;
    
      if (!isset($allowed_protocols)) {
        $allowed_protocols = array_flip(variable_get('filter_allowed_protocols', array('ftp', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'rtsp', 'sftp', 'ssh', 'telnet', 'webcal')));
      }
    
      // Get the plain text representation of the attribute value (i.e. its meaning).
      if ($decode) {
        $string = decode_entities($string);
      }
    
      // Iteratively remove any invalid protocol found.
      do {
        $before = $string;
        $colonpos = strpos($string, ':');
        if ($colonpos > 0) {
          // We found a colon, possibly a protocol. Verify.
          $protocol = substr($string, 0, $colonpos);
          // If a colon is preceded by a slash, question mark or hash, it cannot
          // possibly be part of the URL scheme. This must be a relative URL,
          // which inherits the (safe) protocol of the base document.
          if (preg_match('![/?#]!', $protocol)) {
            break;
          }
          // Per RFC2616, section 3.2.3 (URI Comparison) scheme comparison must be case-insensitive
          // Check if this is a disallowed protocol.
          if (!isset($allowed_protocols[strtolower($protocol)])) {
            $string = substr($string, $colonpos + 1);
          }
        }
      } while ($before != $string);
    
      return check_plain($string);
    }
    
    /**
     * @} End of "defgroup sanitization".
     */
    
    /**
     * @defgroup format Formatting
     * @{
     * Functions to format numbers, strings, dates, etc.
     */
    
    /**
     * Formats an RSS channel.
     *
     * Arbitrary elements may be added using the $args associative array.
     */
    function format_rss_channel($title, $link, $description, $items, $langcode = NULL, $args = array()) {
      global $language;
      $langcode = $langcode ? $langcode : $language->language;
    
      $output = "<channel>\n";
      $output .= ' <title>' . check_plain($title) . "</title>\n";
      $output .= ' <link>' . check_url($link) . "</link>\n";
    
      // The RSS 2.0 "spec" doesn't indicate HTML can be used in the description.
      // We strip all HTML tags, but need to prevent double encoding from properly
      // escaped source data (such as &amp becoming &amp;amp;).
      $output .= ' <description>' . check_plain(decode_entities(strip_tags($description))) . "</description>\n";
      $output .= ' <language>' . check_plain($langcode) . "</language>\n";
      $output .= format_xml_elements($args);
      $output .= $items;
      $output .= "</channel>\n";
    
      return $output;
    }
    
    /**
     * Format a single RSS item.
     *
     * Arbitrary elements may be added using the $args associative array.
     */
    function format_rss_item($title, $link, $description, $args = array()) {
      $output = "<item>\n";
      $output .= ' <title>' . check_plain($title) . "</title>\n";
      $output .= ' <link>' . check_url($link) . "</link>\n";
      $output .= ' <description>' . check_plain($description) . "</description>\n";
      $output .= format_xml_elements($args);
      $output .= "</item>\n";
    
      return $output;
    }
    
    /**
     * Format XML elements.
     *
     * @param $array
     *   An array where each item represent an element and is either a:
     *   - (key => value) pair (<key>value</key>)
     *   - Associative array with fields:
     *     - 'key': element name
     *     - 'value': element contents
     *     - 'attributes': associative array of element attributes
     *
     * In both cases, 'value' can be a simple string, or it can be another array
     * with the same format as $array itself for nesting.
     */
    function format_xml_elements($array) {
      $output = '';
      foreach ($array as $key => $value) {
        if (is_numeric($key)) {
          if ($value['key']) {
            $output .= ' <' . $value['key'];
            if (isset($value['attributes']) && is_array($value['attributes'])) {
              $output .= drupal_attributes($value['attributes']);
            }
    
            if (isset($value['value']) && $value['value'] != '') {
              $output .= '>' . (is_array($value['value']) ? format_xml_elements($value['value']) : check_plain($value['value'])) . '</' . $value['key'] . ">\n";
            }
            else {
              $output .= " />\n";
            }
          }
        }
        else {
          $output .= ' <' . $key . '>' . (is_array($value) ? format_xml_elements($value) : check_plain($value)) . "</$key>\n";
        }
      }
      return $output;
    }
    
    /**
     * Format a string containing a count of items.
     *
     * This function ensures that the string is pluralized correctly. Since t() is
     * called by this function, make sure not to pass already-localized strings to
     * it.
     *
     * For example:
     * @code
     *   $output = format_plural($node->comment_count, '1 comment', '@count comments');
     * @endcode
     *
     * Example with additional replacements:
     * @code
     *   $output = format_plural($update_count,
     *     'Changed the content type of 1 post from %old-type to %new-type.',
     *     'Changed the content type of @count posts from %old-type to %new-type.',
     *     array('%old-type' => $info->old_type, '%new-type' => $info->new_type)));
     * @endcode
     *
     * @param $count
     *   The item count to display.
     * @param $singular
     *   The string for the singular case. Please make sure it is clear this is
     *   singular, to ease translation (e.g. use "1 new comment" instead of "1 new").
     *   Do not use @count in the singular string.
     * @param $plural
     *   The string for the plural case. Please make sure it is clear this is plural,
     *   to ease translation. Use @count in place of the item count, as in "@count
     *   new comments".
     * @param $args
     *   An associative array of replacements to make after translation. Incidences
     *   of any key in this array are replaced with the corresponding value.
     *   Based on the first character of the key, the value is escaped and/or themed:
     *    - !variable: inserted as is
     *    - @variable: escape plain text to HTML (check_plain)
     *    - %variable: escape text and theme as a placeholder for user-submitted
     *      content (check_plain + theme_placeholder)
     *   Note that you do not need to include @count in this array.
     *   This replacement is done automatically for the plural case.
     * @param $options
     *   An associative array of additional options, with the following keys:
     *     - 'langcode' (default to the current language) The language code to
     *       translate to a language other than what is used to display the page.
     *     - 'context' (default to the empty context) The context the source string
     *       belongs to.
     * @return
     *   A translated string.
     */
    function format_plural($count, $singular, $plural, array $args = array(), array $options = array()) {
      $args['@count'] = $count;
      if ($count == 1) {
        return t($singular, $args, $options);
      }
    
      // Get the plural index through the gettext formula.
      $index = (function_exists('locale_get_plural')) ? locale_get_plural($count, isset($options['langcode']) ? $options['langcode'] : NULL) : -1;
      // Backwards compatibility.
      if ($index < 0) {
        return t($plural, $args, $options);
      }
      else {
        switch ($index) {
          case "0":
            return t($singular, $args, $options);
          case "1":
            return t($plural, $args, $options);
          default:
            unset($args['@count']);
            $args['@count[' . $index . ']'] = $count;
            return t(strtr($plural, array('@count' => '@count[' . $index . ']')), $args, $options);
        }
      }
    }
    
    /**
     * Parse a given byte count.
     *
     * @param $size
     *   A size expressed as a number of bytes with optional SI or IEC binary unit
     *   prefix (e.g. 2, 3K, 5MB, 10G, 6GiB, 8 bytes, 9mbytes).
     * @return
     *   An integer representation of the size in bytes.
     */
    function parse_size($size) {
      $unit = preg_replace('/[^bkmgtpezy]/i', '', $size); // Remove the non-unit characters from the size.
      $size = preg_replace('/[^0-9\.]/', '', $size); // Remove the non-numeric characters from the size.
      if ($unit) {
        // Find the position of the unit in the ordered string which is the power of magnitude to multiply a kilobyte by.
        return round($size * pow(DRUPAL_KILOBYTE, stripos('bkmgtpezy', $unit[0])));
      }
      else {
        return round($size);
      }
    }
    
    /**
     * Generate a string representation for the given byte count.
     *
     * @param $size
     *   A size in bytes.
     * @param $langcode
     *   Optional language code to translate to a language other than what is used
     *   to display the page.
     * @return
     *   A translated string representation of the size.
     */
    function format_size($size, $langcode = NULL) {
      if ($size < DRUPAL_KILOBYTE) {
        return format_plural($size, '1 byte', '@count bytes', array(), array('langcode' => $langcode));
      }
      else {
        $size = $size / DRUPAL_KILOBYTE; // Convert bytes to kilobytes.
        $units = array(
          t('@size KB', array(), array('langcode' => $langcode)),
          t('@size MB', array(), array('langcode' => $langcode)),
          t('@size GB', array(), array('langcode' => $langcode)),
          t('@size TB', array(), array('langcode' => $langcode)),
          t('@size PB', array(), array('langcode' => $langcode)),
          t('@size EB', array(), array('langcode' => $langcode)),
          t('@size ZB', array(), array('langcode' => $langcode)),
          t('@size YB', array(), array('langcode' => $langcode)),
        );
        foreach ($units as $unit) {
          if (round($size, 2) >= DRUPAL_KILOBYTE) {
            $size = $size / DRUPAL_KILOBYTE;
          }
          else {
            break;
          }
        }
        return str_replace('@size', round($size, 2), $unit);
      }
    }
    
    /**
     * Format a time interval with the requested granularity.
     *
     * @param $timestamp
     *   The length of the interval in seconds.
     * @param $granularity
     *   How many different units to display in the string.
     * @param $langcode
     *   Optional language code to translate to a language other than
     *   what is used to display the page.
     * @return
     *   A translated string representation of the interval.
     */
    function format_interval($timestamp, $granularity = 2, $langcode = NULL) {
      $units = array(
        '1 year|@count years' => 31536000,
        '1 month|@count months' => 2592000,
        '1 week|@count weeks' => 604800,
        '1 day|@count days' => 86400,
        '1 hour|@count hours' => 3600,
        '1 min|@count min' => 60,
        '1 sec|@count sec' => 1
      );
      $output = '';
      foreach ($units as $key => $value) {
        $key = explode('|', $key);
        if ($timestamp >= $value) {
          $output .= ($output ? ' ' : '') . format_plural(floor($timestamp / $value), $key[0], $key[1], array(), array('langcode' => $langcode));
          $timestamp %= $value;
          $granularity--;
        }
    
        if ($granularity == 0) {
          break;
        }
      }
      return $output ? $output : t('0 sec', array(), array('langcode' => $langcode));
    }
    
    /**
     * Format a date with the given configured format or a custom format string.
     *
     * Drupal allows administrators to select formatting strings for 'short',
     * 'medium' and 'long' date formats. This function can handle these formats,
     * as well as any custom format.
     *
     * @param $timestamp
     *   The exact date to format, as a UNIX timestamp.
     * @param $type
     *   The format to use. Can be "short", "medium" or "long" for the preconfigured
     *   date formats. If "custom" is specified, then $format is required as well.
     * @param $format
     *   A PHP date format string as required by date(). A backslash should be used
     *   before a character to avoid interpreting the character as part of a date
     *   format.
     * @param $timezone
     *   Time zone identifier; if omitted, the user's time zone is used.
     * @param $langcode
     *   Optional language code to translate to a language other than what is used
     *   to display the page.
     * @return
     *   A translated date string in the requested format.
     */
    function format_date($timestamp, $type = 'medium', $format = '', $timezone = NULL, $langcode = NULL) {
      $timezones = &drupal_static(__FUNCTION__, array());
      if (!isset($timezone)) {
        global $user;
        if (variable_get('configurable_timezones', 1) && $user->uid && $user->timezone) {
          $timezone = $user->timezone;
        }
        else {
          $timezone = variable_get('date_default_timezone', 'UTC');
        }
      }
      // Store DateTimeZone objects in an array rather than repeatedly
      // contructing identical objects over the life of a request.
      if (!isset($timezones[$timezone])) {
        $timezones[$timezone] = timezone_open($timezone);
      }
    
      // Use the default langcode if none is set.
      global $language;
      if (empty($langcode)) {
        $langcode = isset($language->language) ? $language->language : 'en';
      }
    
      switch ($type) {
        case 'short':
          $format = variable_get('date_format_short', 'm/d/Y - H:i');
          break;
        case 'long':
          $format = variable_get('date_format_long', 'l, F j, Y - H:i');
          break;
        case 'custom':
          // No change to format.
          break;
        case 'medium':
        default:
          $format = variable_get('date_format_medium', 'D, m/d/Y - H:i');
      }
    
      // Create a DateTime object from the timestamp.
      $date_time = date_create('@' . $timestamp);
      // Set the time zone for the DateTime object.
      date_timezone_set($date_time, $timezones[$timezone]);
    
      // Encode markers that should be translated. 'A' becomes '\xEF\AA\xFF'.
      // xEF and xFF are invalid UTF-8 sequences, and we assume they are not in the
      // input string.
      // Paired backslashes are isolated to prevent errors in read-ahead evaluation.
      // The read-ahead expression ensures that A matches, but not \A.
      $format = preg_replace(array('/\\\\\\\\/', '/(?<!\\\\)([AaeDlMTF])/'), array("\xEF\\\\\\\\\xFF", "\xEF\\\\\$1\$1\xFF"), $format);
    
      // Call date_format().
      $format = date_format($date_time, $format);
    
      // Pass the langcode to _format_date_callback().
      _format_date_callback(NULL, $langcode);
    
      // Translate the marked sequences.
      return preg_replace_callback('/\xEF([AaeDlMTF]?)(.*?)\xFF/', '_format_date_callback', $format);
    }
    
    /**
     * Callback function for preg_replace_callback().
     */
    function _format_date_callback(array $matches = NULL, $new_langcode = NULL) {
      // We cache translations to avoid redundant and rather costly calls to t().
      static $cache, $langcode;
    
      if (!isset($matches)) {
        $langcode = $new_langcode;
        return;
      }
    
      $code = $matches[1];
      $string = $matches[2];
    
      if (!isset($cache[$langcode][$code][$string])) {
        $options = array(
          'langcode' => $langcode,
        );
    
        if ($code == 'F') {
          $options['context'] = 'Long month name';
        }
    
        if ($code == '') {
          $cache[$langcode][$code][$string] = $string;
        }
        else {
          $cache[$langcode][$code][$string] = t($string, array(), $options);
        }
      }
      return $cache[$langcode][$code][$string];
    }
    
    /**
     * @} End of "defgroup format".
     */
    
    /**
     * Generate a URL from a Drupal menu path. Will also pass-through existing URLs.
     *
     * @param $path
     *   The Drupal path being linked to, such as "admin/content", or an
     *   existing URL like "http://drupal.org/". The special path
     *   '<front>' may also be given and will generate the site's base URL.
     * @param $options
     *   An associative array of additional options, with the following keys:
     *   - 'query'
     *       A URL-encoded query string to append to the link, or an array of query
     *       key/value-pairs without any URL-encoding.
     *   - 'fragment'
     *       A fragment identifier (or named anchor) to append to the link.
     *       Do not include the '#' character.
     *   - 'absolute' (default FALSE)
     *       Whether to force the output to be an absolute link (beginning with
     *       http:). Useful for links that will be displayed outside the site, such
     *       as in an RSS feed.
     *   - 'alias' (default FALSE)
     *       Whether the given path is an alias already.
     *   - 'external'
     *       Whether the given path is an external URL.
     *   - 'language'
     *       An optional language object. Used to build the URL to link to and
     *       look up the proper alias for the link.
     *   - 'https'
     *       Whether this URL should point to a secure location. If not specified,
     *       the current scheme is used, so the user stays on http or https
     *       respectively. TRUE enforces HTTPS and FALSE enforces HTTP, but HTTPS
     *       can only be enforced when the variable 'https' is set to TRUE.
     *   - 'base_url'
     *       Only used internally, to modify the base URL when a language dependent
     *       URL requires so.
     *   - 'prefix'
     *       Only used internally, to modify the path when a language dependent URL
     *       requires so.
     * @return
     *   A string containing a URL to the given path.
     *
     * When creating links in modules, consider whether l() could be a better
     * alternative than url().
     */
    function url($path = NULL, array $options = array()) {
      // Merge in defaults.
      $options += array(
        'fragment' => '',
        'query' => '',
        'absolute' => FALSE,
        'alias' => FALSE,
        'https' => FALSE,
        'prefix' => ''
      );
      if (!isset($options['external'])) {
        // Return an external link if $path contains an allowed absolute URL.
        // Only call the slow filter_xss_bad_protocol if $path contains a ':' before
        // any / ? or #.
        $colonpos = strpos($path, ':');
        $options['external'] = ($colonpos !== FALSE && !preg_match('![/?#]!', substr($path, 0, $colonpos)) && filter_xss_bad_protocol($path, FALSE) == check_plain($path));
      }
    
      // May need language dependent rewriting if language.inc is present.
      if (function_exists('language_url_rewrite')) {
        language_url_rewrite($path, $options);
      }
      if ($options['fragment']) {
        $options['fragment'] = '#' . $options['fragment'];
      }
      if (is_array($options['query'])) {
        $options['query'] = drupal_query_string_encode($options['query']);
      }
    
      if ($options['external']) {
        // Split off the fragment.
        if (strpos($path, '#') !== FALSE) {
          list($path, $old_fragment) = explode('#', $path, 2);
          if (isset($old_fragment) && !$options['fragment']) {
            $options['fragment'] = '#' . $old_fragment;
          }
        }
        // Append the query.
        if ($options['query']) {
          $path .= (strpos($path, '?') !== FALSE ? '&' : '?') . $options['query'];
        }
        // Reassemble.
        return $path . $options['fragment'];
      }
    
      global $base_url, $base_secure_url, $base_insecure_url;
      $script = &drupal_static(__FUNCTION__);
    
      if (!isset($script)) {
        // On some web servers, such as IIS, we can't omit "index.php". So, we
        // generate "index.php?q=foo" instead of "?q=foo" on anything that is not
        // Apache.
        $script = (strpos($_SERVER['SERVER_SOFTWARE'], 'Apache') === FALSE) ? 'index.php' : '';
      }
    
      // The base_url might be rewritten from the language rewrite in domain mode.
      if (!isset($options['base_url'])) {
        if (isset($options['https']) && variable_get('https', FALSE)) {
          if ($options['https'] === TRUE) {
            $options['base_url'] = $base_secure_url;
            $options['absolute'] = TRUE;
          }
          elseif ($options['https'] === FALSE) {
            $options['base_url'] = $base_insecure_url;
            $options['absolute'] = TRUE;
          }
        }
        else {
          $options['base_url'] = $base_url;
        }
      }
    
      // Preserve the original path before aliasing.
      $original_path = $path;
    
      // The special path '<front>' links to the default front page.
      if ($path == '<front>') {
        $path = '';
      }
      elseif (!empty($path) && !$options['alias']) {
        $path = drupal_get_path_alias($path, isset($options['language']) ? $options['language']->language : '');
      }
    
      if (function_exists('custom_url_rewrite_outbound')) {
        // Modules may alter outbound links by reference.
        custom_url_rewrite_outbound($path, $options, $original_path);
      }
    
      $base = $options['absolute'] ? $options['base_url'] . '/' : base_path();
      $prefix = empty($path) ? rtrim($options['prefix'], '/') : $options['prefix'];
      $path = drupal_encode_path($prefix . $path);
    
      if (variable_get('clean_url', '0')) {
        // With Clean URLs.
        if ($options['query']) {
          return $base . $path . '?' . $options['query'] . $options['fragment'];
        }
        else {
          return $base . $path . $options['fragment'];
        }
      }
      else {
        // Without Clean URLs.
        $variables = array();
        if (!empty($path)) {
          $variables[] = 'q=' . $path;
        }
        if (!empty($options['query'])) {
          $variables[] = $options['query'];
        }
        if ($query = join('&', $variables)) {
          return $base . $script . '?' . $query . $options['fragment'];
        }
        else {
          return $base . $options['fragment'];
        }
      }
    }
    
    /**
     * Format an attribute string to insert in a tag.
     *
     * Each array key and its value will be formatted into an HTML attribute string.
     * If a value is itself an array, then each array element is concatenated with a
     * space between each value (e.g. a multi-value class attribute).
     *
     * @param $attributes
     *   An associative array of HTML attributes.
     * @return
     *   An HTML string ready for insertion in a tag.
     */
    function drupal_attributes(array $attributes = array()) {
      foreach ($attributes as $attribute => &$data) {
        if (is_array($data)) {
          $data = implode(' ', $data);
        }
        $data = $attribute . '="' . check_plain($data) . '"';
      }
      return $attributes ? ' ' . implode(' ', $attributes) : '';
    }
    
    /**
     * Format an internal Drupal link.
     *
     * This function correctly handles aliased paths, and allows themes to highlight
     * links to the current page correctly, so all internal links output by modules
     * should be generated by this function if possible.
     *
     * @param $text
     *   The text to be enclosed with the anchor tag.
     * @param $path
     *   The Drupal path being linked to, such as "admin/content". Can be an
     *   external or internal URL.
     *     - If you provide the full URL, it will be considered an external URL.
     *     - If you provide only the path (e.g. "admin/content"), it is
     *       considered an internal link. In this case, it must be a system URL
     *       as the url() function will generate the alias.
     *     - If you provide '<front>', it generates a link to the site's
     *       base URL (again via the url() function).
     *     - If you provide a path, and 'alias' is set to TRUE (see below), it is
     *       used as is.
     * @param $options
     *   An associative array of additional options, with the following keys:
     *     - 'attributes'
     *       An associative array of HTML attributes to apply to the anchor tag.
     *     - 'query'
     *       A query string to append to the link, or an array of query key/value
     *       properties.
     *     - 'fragment'
     *       A fragment identifier (named anchor) to append to the link.
     *       Do not include the '#' character.
     *     - 'absolute' (default FALSE)
     *       Whether to force the output to be an absolute link (beginning with
     *       http:). Useful for links that will be displayed outside the site, such
     *       as in an RSS feed.
     *     - 'html' (default FALSE)
     *       Whether $text is HTML, or just plain-text. For example for making
     *       an image a link, this must be set to TRUE, or else you will see the
     *       escaped HTML.
     *     - 'alias' (default FALSE)
     *       Whether the given path is an alias already.
     * @return
     *   an HTML string containing a link to the given path.
     */
    function l($text, $path, array $options = array()) {
      global $language;
    
      // Merge in defaults.
      $options += array(
          'attributes' => array(),
          'html' => FALSE,
        );
    
      // Append active class.
      if (($path == $_GET['q'] || ($path == '<front>' && drupal_is_front_page())) &&
          (empty($options['language']) || $options['language']->language == $language->language)) {
        $options['attributes']['class'][] = 'active';
      }
    
      // Remove all HTML and PHP tags from a tooltip. For best performance, we act only
      // if a quick strpos() pre-check gave a suspicion (because strip_tags() is expensive).
      if (isset($options['attributes']['title']) && strpos($options['attributes']['title'], '<') !== FALSE) {
        $options['attributes']['title'] = strip_tags($options['attributes']['title']);
      }
    
      return '<a href="' . check_plain(url($path, $options)) . '"' . drupal_attributes($options['attributes']) . '>' . ($options['html'] ? $text : check_plain($text)) . '</a>';
    }
    
    /**
     * Perform end-of-request tasks.
     *
     * This function sets the page cache if appropriate, and allows modules to
     * react to the closing of the page by calling hook_exit().
     */
    function drupal_page_footer() {
      global $user;
    
      module_invoke_all('exit');
    
      // Commit the user session, if needed.
      drupal_session_commit();
    
      if (variable_get('cache', CACHE_DISABLED) != CACHE_DISABLED && ($cache = drupal_page_set_cache())) {
        drupal_serve_page_from_cache($cache);
      }
      else {
        ob_flush();
      }
    
      _registry_check_code(REGISTRY_WRITE_LOOKUP_CACHE);
      drupal_cache_system_paths();
    }
    
    /**
     * Form an associative array from a linear array.
     *
     * This function walks through the provided array and constructs an associative
     * array out of it. The keys of the resulting array will be the values of the
     * input array. The values will be the same as the keys unless a function is
     * specified, in which case the output of the function is used for the values
     * instead.
     *
     * @param $array
     *   A linear array.
     * @param $function
     *   A name of a function to apply to all values before output.
     * @result
     *   An associative array.
     */
    function drupal_map_assoc($array, $function = NULL) {
      if (!isset($function)) {
        $result = array();
        foreach ($array as $value) {
          $result[$value] = $value;
        }
        return $result;
      }
      elseif (function_exists($function)) {
        $result = array();
        foreach ($array as $value) {
          $result[$value] = $function($value);
        }
        return $result;
      }
    }
    
    /**
     * Attempts to set the PHP maximum execution time.
     *
     * This function is a wrapper around the PHP function set_time_limit().
     * When called, set_time_limit() restarts the timeout counter from zero.
     * In other words, if the timeout is the default 30 seconds, and 25 seconds
     * into script execution a call such as set_time_limit(20) is made, the
     * script will run for a total of 45 seconds before timing out.
     *
     * It also means that it is possible to decrease the total time limit if
     * the sum of the new time limit and the current time spent running the
     * script is inferior to the original time limit. It is inherent to the way
     * set_time_limit() works, it should rather be called with an appropriate
     * value every time you need to allocate a certain amount of time
     * to execute a task than only once at the beginning of the script.
     *
     * Before calling set_time_limit(), we check if this function is available
     * because it could be disabled by the server administrator. We also hide all
     * the errors that could occur when calling set_time_limit(), because it is
     * not possible to reliably ensure that PHP or a security extension will
     * not issue a warning/error if they prevent the use of this function.
     *
     * @param $time_limit
     *   An integer specifying the new time limit, in seconds. A value of 0
     *   indicates unlimited execution time.
     */
    function drupal_set_time_limit($time_limit) {
      if (function_exists('set_time_limit')) {
        @set_time_limit($time_limit);
      }
    }
    
    /**
     * Returns the path to a system item (module, theme, etc.).
     *
     * @param $type
     *   The type of the item (i.e. theme, theme_engine, module).
     * @param $name
     *   The name of the item for which the path is requested.
     *
     * @return
     *   The path to the requested item.
     */
    function drupal_get_path($type, $name) {
      return dirname(drupal_get_filename($type, $name));
    }
    
    /**
     * Return the base URL path (i.e., directory) of the Drupal installation.
     *
     * base_path() prefixes and suffixes a "/" onto the returned path if the path is
     * not empty. At the very least, this will return "/".
     *
     * Examples:
     * - http://example.com returns "/" because the path is empty.
     * - http://example.com/drupal/folder returns "/drupal/folder/".
     */
    function base_path() {
      return $GLOBALS['base_path'];
    }
    
    /**
     * Add a <link> tag to the page's HEAD.
     *
     * This function can be called as long the HTML header hasn't been sent.
     */
    function drupal_add_link($attributes) {
      drupal_add_html_head('<link' . drupal_attributes($attributes) . " />\n");
    }
    
    /**
     * Adds a cascading stylesheet to the stylesheet queue.
     *
     * Calling drupal_static_reset('drupal_add_css') will clear all cascading
     * stylesheets added so far.
     *
     * @param $data
     *   (optional) The stylesheet data to be added, depending on what is passed
     *   through to the $options['type'] parameter:
     *   - 'file': The path to the CSS file relative to the base_path(),
     *     e.g., "modules/devel/devel.css".
     *
     *     Modules should always prefix the names of their CSS files with the
     *     module name, for example: system-menus.css rather than simply menus.css.
     *     Themes can override module-supplied CSS files based on their filenames,
     *     and this prefixing helps prevent confusing name collisions for theme
     *     developers. See drupal_get_css where the overrides are performed.
     *
     *     If the direction of the current language is right-to-left (Hebrew,
     *     Arabic, etc.), the function will also look for an RTL CSS file and append
     *     it to the list. The name of this file should have an '-rtl.css' suffix.
     *     For example a CSS file called 'mymodule-name.css' will have a
     *     'mymodule-name-rtl.css' file added to the list, if exists in the same
     *     directory. This CSS file should contain overrides for properties which
     *     should be reversed or otherwise different in a right-to-left display.
     *   - 'inline': A string of CSS that should be placed in the given scope. Note
     *     that it is better practice to use 'file' stylesheets, rather than 'inline'
     *     as the CSS would then be aggregated and cached.
     *   - 'external': The absolute path to an external CSS file that is not hosted
     *     on the local server. These files will not be aggregated if CSS aggregation
     *     is enabled.
     *
     * @param $options
     *   (optional) A string defining the 'type' of CSS that is being added in the
     *   $data parameter ('file'/'inline'), or an array which can have any or all of
     *   the following keys:
     *   - 'type': The type of stylesheet being added. Available options are 'file',
     *     'inline' or 'external'. Defaults to 'file'.
     *   - 'weight': The weight of the stylesheet specifies the order in which the
     *     CSS will appear when presented on the page.
     *
     *       Available constants are:
     *       - CSS_SYSTEM: Any system-layer CSS.
     *       - CSS_DEFAULT: Any module-layer CSS.
     *       - CSS_THEME: Any theme-layer CSS.
     *
     *       If you need to embed a CSS file before any other module's stylesheets,
     *       for example, you would use CSS_DEFAULT - 1. Note that inline CSS is
     *       simply appended to the end of the specified scope (region), so they
     *       always come last.
     *
     *   - 'media': The media type for the stylesheet, e.g., all, print, screen.
     *     Defaults to 'all'.
     *   - 'preprocess': Allows the CSS to be aggregated and compressed if the
     *     Optimize CSS feature has been turned on under the performance section.
     *     Defaults to TRUE.
     *
     *     What does this actually mean?
     *     CSS preprocessing is the process of aggregating a bunch of separate CSS
     *     files into one file that is then compressed by removing all extraneous
     *     white space. Note that preprocessed inline stylesheets will not be
     *     aggregated into this single file, instead it will just be compressed
     *     when being output on the page. External stylesheets will not be
     *     aggregated.
     *
     *     The reason for merging the CSS files is outlined quite thoroughly here:
     *     http://www.die.net/musings/page_load_time/
     *     "Load fewer external objects. Due to request overhead, one bigger file
     *     just loads faster than two smaller ones half its size."
     *
     *     However, you should *not* preprocess every file as this can lead to
     *     redundant caches. You should set $preprocess = FALSE when your styles
     *     are only used rarely on the site. This could be a special admin page,
     *     the homepage, or a handful of pages that does not represent the
     *     majority of the pages on your site.
     *
     *     Typical candidates for caching are for example styles for nodes across
     *     the site, or used in the theme.
     * @return
     *   An array of queued cascading stylesheets.
     */
    function drupal_add_css($data = NULL, $options = NULL) {
      $css = &drupal_static(__FUNCTION__, array());
    
      // Construct the options, taking the defaults into consideration.
      if (isset($options)) {
        if (!is_array($options)) {
          $options = array('type' => $options);
        }
      }
      else {
        $options = array();
      }
    
      // Create an array of CSS files for each media type first, since each type needs to be served
      // to the browser differently.
      if (isset($data)) {
        $options += array(
          'type' => 'file',
          'weight' => CSS_DEFAULT,
          'media' => 'all',
          'preprocess' => TRUE,
          'data' => $data,
        );
    
        // Always add a tiny value to the weight, to conserve the insertion order.
        $options['weight'] += count($css) / 1000;
    
        // Add the data to the CSS array depending on the type.
        switch ($options['type']) {
          case 'inline':
            // For inline stylesheets, we don't want to use the $data as the array
            // key as $data could be a very long string of CSS.
            $css[] = $options;
            break;
          default:
            // Local and external files must keep their name as the associative key
            // so the same CSS file is not be added twice.
            $css[$data] = $options;
        }
      }
    
      return $css;
    }
    
    /**
     * Returns a themed representation of all stylesheets that should be attached to the page.
     *
     * It loads the CSS in order, with 'module' first, then 'theme' afterwards.
     * This ensures proper cascading of styles so themes can easily override
     * module styles through CSS selectors.
     *
     * Themes may replace module-defined CSS files by adding a stylesheet with the
     * same filename. For example, themes/garland/system-menus.css would replace
     * modules/system/system-menus.css. This allows themes to override complete
     * CSS files, rather than specific selectors, when necessary.
     *
     * If the original CSS file is being overridden by a theme, the theme is
     * responsible for supplying an accompanying RTL CSS file to replace the
     * module's.
     *
     * @param $css
     *   (optional) An array of CSS files. If no array is provided, the default
     *   stylesheets array is used instead.
     * @return
     *   A string of XHTML CSS tags.
     */
    function drupal_get_css($css = NULL) {
      $output = '';
      if (!isset($css)) {
        $css = drupal_add_css();
      }
    
      $preprocess_css = (variable_get('preprocess_css', FALSE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update'));
      $directory = file_directory_path('public');
      $is_writable = is_dir($directory) && is_writable($directory);
    
      // A dummy query-string is added to filenames, to gain control over
      // browser-caching. The string changes on every update or full cache
      // flush, forcing browsers to load a new copy of the files, as the
      // URL changed.
      $query_string = '?' . substr(variable_get('css_js_query_string', '0'), 0, 1);
    
      // Allow modules to alter the css items.
      drupal_alter('css', $css);
    
      // Sort css items according to their weights.
      uasort($css, 'drupal_sort_weight');
    
      // Remove the overriden CSS files. Later CSS files override former ones.
      $previous_item = array();
      foreach ($css as $key => $item) {
        if ($item['type'] == 'file') {
          $basename = basename($item['data']);
          if (isset($previous_item[$basename])) {
            // Remove the previous item that shared the same base name.
            unset($css[$previous_item[$basename]]);
          }
          $previous_item[$basename] = $key;
        }
      }
    
      // If CSS preprocessing is off, we still need to output the styles.
      // Additionally, go through any remaining styles if CSS preprocessing is on and output the non-cached ones.
      $rendered_css = array();
      $inline_css = '';
      $external_css = '';
      $preprocess_items = array();
      foreach ($css as $data => $item) {
        // Loop through each of the stylesheets, including them appropriately based
        // on their type.
        switch ($item['type']) {
          case 'file':
            // Depending on whether aggregation is desired, include the file.
            if (!$item['preprocess'] || !($is_writable && $preprocess_css)) {
              $rendered_css[] = '<link type="text/css" rel="stylesheet" media="' . $item['media'] . '" href="' . file_create_url($item['data']) . $query_string . '" />';
            }
            else {
              $preprocess_items[$item['media']][] = $item;
              // Mark the position of the preprocess element,
              // it should be at the position of the first preprocessed file.
              $rendered_css['preprocess'] = '';
            }
            break;
          case 'inline':
            // Include inline stylesheets.
            $inline_css .= drupal_load_stylesheet_content($item['data'], $item['preprocess']);
            break;
          case 'external':
            // Preprocessing for external CSS files is ignored.
            $external_css .= '<link type="text/css" rel="stylesheet" media="' . $item['media'] . '" href="' . $item['data'] . '" />' . "\n";
            break;
        }
      }
    
      if (!empty($preprocess_items)) {
        foreach ($preprocess_items as $media => $items) {
          // Prefix filename to prevent blocking by firewalls which reject files
          // starting with "ad*".
          $filename = 'css_' . md5(serialize($items) . $query_string) . '.css';
          $preprocess_file = file_create_url(drupal_build_css_cache($items, $filename));
          $rendered_css['preprocess'] .= '<link type="text/css" rel="stylesheet" media="' . $media . '" href="' . $preprocess_file . '" />' . "\n";
        }
      }
      // Enclose the inline CSS with the style tag if required.
      if (!empty($inline_css)) {
        $inline_css = "\n" . '<style type="text/css">' . $inline_css .'</style>';
      }
    
      // Output all the CSS files with the inline stylesheets showing up last.
      return implode("\n", $rendered_css) . $external_css . $inline_css;
    }
    
    /**
     * Aggregate and optimize CSS files, putting them in the files directory.
     *
     * @param $css
     *   An array of CSS files to aggregate and compress into one file.
     * @param $filename
     *   The name of the aggregate CSS file.
     * @return
     *   The name of the CSS file.
     */
    function drupal_build_css_cache($css, $filename) {
      $data = '';
    
      // Create the css/ within the files folder.
      $csspath = 'public://css';
      file_prepare_directory($csspath, FILE_CREATE_DIRECTORY);
      if (!file_exists($csspath . '/' . $filename)) {
        // Build aggregate CSS file.
        foreach ($css as $stylesheet) {
          // Only 'file' stylesheets can be aggregated.
          if ($stylesheet['type'] == 'file') {
            $contents = drupal_load_stylesheet($stylesheet['data'], TRUE);
            // Return the path to where this CSS file originated from.
            $base = base_path() . dirname($stylesheet['data']) . '/';
            _drupal_build_css_path(NULL, $base);
            // Prefix all paths within this CSS file, ignoring external and absolute paths.
            $data .= preg_replace_callback('/url\([\'"]?(?![a-z]+:|\/+)([^\'")]+)[\'"]?\)/i', '_drupal_build_css_path', $contents);
          }
        }
    
        // Per the W3C specification at http://www.w3.org/TR/REC-CSS2/cascade.html#at-import,
        // @import rules must proceed any other style, so we move those to the top.
        $regexp = '/@import[^;]+;/i';
        preg_match_all($regexp, $data, $matches);
        $data = preg_replace($regexp, '', $data);
        $data = implode('', $matches[0]) . $data;
    
        // Create the CSS file.
        file_unmanaged_save_data($data, $csspath . '/' . $filename, FILE_EXISTS_REPLACE);
      }
      return $csspath . '/' . $filename;
    }
    
    /**
     * Helper function for drupal_build_css_cache().
     *
     * This function will prefix all paths within a CSS file.
     */
    function _drupal_build_css_path($matches, $base = NULL) {
      $_base = &drupal_static(__FUNCTION__);
      // Store base path for preg_replace_callback.
      if (isset($base)) {
        $_base = $base;
      }
    
      // Prefix with base and remove '../' segments where possible.
      $path = $_base . $matches[1];
      $last = '';
      while ($path != $last) {
        $last = $path;
        $path = preg_replace('`(^|/)(?!\.\./)([^/]+)/\.\./`', '$1', $path);
      }
      return 'url(' . $path . ')';
    }
    
    /**
     * Loads the stylesheet and resolves all @import commands.
     *
     * Loads a stylesheet and replaces @import commands with the contents of the
     * imported file. Use this instead of file_get_contents when processing
     * stylesheets.
     *
     * The returned contents are compressed removing white space and comments only
     * when CSS aggregation is enabled. This optimization will not apply for
     * color.module enabled themes with CSS aggregation turned off.
     *
     * @param $file
     *   Name of the stylesheet to be processed.
     * @param $optimize
     *   Defines if CSS contents should be compressed or not.
     * @return
     *   Contents of the stylesheet, including any resolved @import commands.
     */
    function drupal_load_stylesheet($file, $optimize = NULL) {
      // $_optimize does not use drupal_static as it is set by $optimize.
      static $_optimize;
      // Store optimization parameter for preg_replace_callback with nested @import loops.
      if (isset($optimize)) {
        $_optimize = $optimize;
      }
    
      $contents = '';
      if (file_exists($file)) {
        // Load the local CSS stylesheet.
        $contents = file_get_contents($file);
    
        // Change to the current stylesheet's directory.
        $cwd = getcwd();
        chdir(dirname($file));
    
        // Process the stylesheet.
        $contents = drupal_load_stylesheet_content($contents, $_optimize);
    
        // Change back directory.
        chdir($cwd);
      }
    
      return $contents;
    }
    
    /**
     * Process the contents of a stylesheet for aggregation.
     *
     * @param $contents
     *   The contents of the stylesheet.
     * @param $optimize
     *   (optional) Boolean whether CSS contents should be minified. Defaults to
     *   FALSE.
     * @return
     *   Contents of the stylesheet including the imported stylesheets.
     */
    function drupal_load_stylesheet_content($contents, $optimize = FALSE) {
      // Replaces @import commands with the actual stylesheet content.
      // This happens recursively but omits external files.
      $contents = preg_replace_callback('/@import\s*(?:url\()?[\'"]?(?![a-z]+:)([^\'"\()]+)[\'"]?\)?;/', '_drupal_load_stylesheet', $contents);
      // Remove multiple charset declarations for standards compliance (and fixing Safari problems).
      $contents = preg_replace('/^@charset\s+[\'"](\S*)\b[\'"];/i', '', $contents);
    
      if ($optimize) {
        // Perform some safe CSS optimizations.
        $contents = preg_replace('<
          \s*([@{}:;,]|\)\s|\s\()\s* |  # Remove whitespace around separators, but keep space around parentheses.
          /\*([^*\\\\]|\*(?!/))+\*/ |   # Remove comments that are not CSS hacks.
          [\n\r]                        # Remove line breaks.
          >x', '\1', $contents);
      }
      return $contents;
    }
    
    /**
     * Loads stylesheets recursively and returns contents with corrected paths.
     *
     * This function is used for recursive loading of stylesheets and
     * returns the stylesheet content with all url() paths corrected.
     */
    function _drupal_load_stylesheet($matches) {
      $filename = $matches[1];
      // Load the imported stylesheet and replace @import commands in there as well.
      $file = drupal_load_stylesheet($filename);
      // Alter all url() paths, but not external.
      return preg_replace('/url\(([\'"]?)(?![a-z]+:)([^\'")]+)[\'"]?\)?;/i', 'url(\1' . dirname($filename) . '/', $file);
    }
    
    /**
     * Delete all cached CSS files.
     */
    function drupal_clear_css_cache() {
      file_scan_directory('public://css', '/.*/', array('callback' => 'file_unmanaged_delete'));
    }
    
    /**
     * Add a JavaScript file, setting or inline code to the page.
     *
     * The behavior of this function depends on the parameters it is called with.
     * Generally, it handles the addition of JavaScript to the page, either as
     * reference to an existing file or as inline code. The following actions can be
     * performed using this function:
     *
     * - Add a file ('file'):
     *   Adds a reference to a JavaScript file to the page.
     *
     * - Add inline JavaScript code ('inline'):
     *   Executes a piece of JavaScript code on the current page by placing the code
     *   directly in the page. This can, for example, be useful to tell the user that
     *   a new message arrived, by opening a pop up, alert box etc. This should only
     *   be used for JavaScript which cannot be placed and executed from a file.
     *   When adding inline code, make sure that you are not relying on $ being jQuery.
     *   Wrap your code in (function ($) { ... })(jQuery); or use jQuery instead of $.
     *
     * - Add external JavaScript ('external'):
     *   Allows the inclusion of external JavaScript files that are not hosted on the
     *   local server. Note that these external JavaScript references do not get
     *   aggregated when preprocessing is on.
     *
     * - Add settings ('setting'):
     *   Adds a setting to Drupal's global storage of JavaScript settings. Per-page
     *   settings are required by some modules to function properly. All settings
     *   will be accessible at Drupal.settings.
     *
     * Examples:
     * @code
     *   drupal_add_js('misc/collapse.js');
     *   drupal_add_js('misc/collapse.js', 'file');
     *   drupal_add_js('jQuery(document).ready(function () { alert("Hello!"); });', 'inline');
     *   drupal_add_js('jQuery(document).ready(function () { alert("Hello!"); });',
     *     array('type' => 'inline', 'scope' => 'footer', 'weight' => 5)
     *   );
     *   drupal_add_js('http://example.com/example.js', 'external');
     * @endcode
     *
     * Calling drupal_static_reset('drupal_add_js') will clear all JavaScript added
     * so far.
     *
     * @param $data
     *   (optional) If given, the value depends on the $options parameter:
     *   - 'file': Path to the file relative to base_path().
     *   - 'inline': The JavaScript code that should be placed in the given scope.
     *   - 'external': The absolute path to an external JavaScript file that is not
     *     hosted on the local server. These files will not be aggregated if
     *     JavaScript aggregation is enabled.
     *   - 'setting': An array with configuration options as associative array. The
     *       array is directly placed in Drupal.settings. All modules should wrap
     *       their actual configuration settings in another variable to prevent
     *       the pollution of the Drupal.settings namespace.
     * @param $options
     *   (optional) A string defining the type of JavaScript that is being added
     *   in the $data parameter ('file'/'setting'/'inline'), or an array which
     *   can have any or all of the following keys. JavaScript settings should
     *   always pass the string 'setting' only.
     *   - type
     *       The type of JavaScript that is to be added to the page. Allowed
     *       values are 'file', 'inline', 'external' or 'setting'. Defaults
     *       to 'file'.
     *   - scope
     *       The location in which you want to place the script. Possible values
     *       are 'header' or 'footer'. If your theme implements different regions,
     *       however, you can also use these. Defaults to 'header'.
     *   - weight
     *       A number defining the order in which the JavaScript is added to the
     *       page. In some cases, the order in which the JavaScript is presented
     *       on the page is very important. jQuery, for example, must be added to
     *       to the page before any jQuery code is run, so jquery.js uses a weight
     *       of JS_LIBRARY - 2, drupal.js uses a weight of JS_LIBRARY - 1, and all
     *       following scripts depending on jQuery and Drupal behaviors are simply
     *       added using the default weight of JS_DEFAULT.
     *
     *       Available constants are:
     *       - JS_LIBRARY: Any libraries, settings, or jQuery plugins.
     *       - JS_DEFAULT: Any module-layer JavaScript.
     *       - JS_THEME: Any theme-layer JavaScript.
     *
     *       If you need to invoke a JavaScript file before any other module's
     *       JavaScript, for example, you would use JS_DEFAULT - 1.
     *       Note that inline JavaScripts are simply appended to the end of the
     *       specified scope (region), so they always come last.
     *   - defer
     *       If set to TRUE, the defer attribute is set on the &lt;script&gt; tag.
     *       Defaults to FALSE.
     *   - cache
     *       If set to FALSE, the JavaScript file is loaded anew on every page
     *       call, that means, it is not cached. Used only when 'type' references
     *       a JavaScript file. Defaults to TRUE.
     *   - preprocess
     *       Aggregate the JavaScript if the JavaScript optimization setting has
     *       been toggled in admin/config/development/performance. Note that
     *       JavaScript of type 'external' is not aggregated. Defaults to TRUE.
     * @return
     *   The contructed array of JavaScript files.
     * @see drupal_get_js()
     */
    function drupal_add_js($data = NULL, $options = NULL) {
      $javascript = &drupal_static(__FUNCTION__, array());
    
      // Construct the options, taking the defaults into consideration.
      if (isset($options)) {
        if (!is_array($options)) {
          $options = array('type' => $options);
        }
      }
      else {
        $options = array();
      }
      $options += drupal_js_defaults($data);
    
      // Preprocess can only be set if caching is enabled.
      $options['preprocess'] = $options['cache'] ? $options['preprocess'] : FALSE;
    
      // Tweak the weight so that files of the same weight are included in the
      // order of the calls to drupal_add_js().
      $options['weight'] += count($javascript) / 1000;
    
      if (isset($data)) {
        // Add jquery.js and drupal.js, as well as the basePath setting, the
        // first time a Javascript file is added.
        if (empty($javascript)) {
          $javascript = array(
            'settings' => array(
              'data' => array(
                array('basePath' => base_path()),
              ),
              'type' => 'setting',
              'scope' => 'header',
              'weight' => JS_LIBRARY,
            ),
            'misc/drupal.js' => array(
              'data' => 'misc/drupal.js',
              'type' => 'file',
              'scope' => 'header',
              'weight' => JS_LIBRARY - 1,
              'cache' => TRUE,
              'defer' => FALSE,
              'preprocess' => TRUE,
            ),
          );
          // Register all required libraries.
          drupal_add_library('system', 'jquery');
          drupal_add_library('system', 'once');
        }
    
        switch ($options['type']) {
          case 'setting':
            // All JavaScript settings are placed in the header of the page with
            // the library weight so that inline scripts appear afterwards.
            $javascript['settings']['data'][] = $data;
            break;
    
          case 'inline':
            $javascript[] = $options;
            break;
    
          default: // 'file' and 'external'
            // Local and external files must keep their name as the associative key
            // so the same JavaScript file is not be added twice.
            $javascript[$options['data']] = $options;
        }
      }
      return $javascript;
    }
    
    /**
     * Constructs an array of the defaults that are used for JavaScript items.
     *
     * @param $data
     *   (optional) The default data parameter for the JavaScript item array.
     * @see drupal_get_js()
     * @see drupal_add_js()
     */
    function drupal_js_defaults($data = NULL) {
      return array(
        'type' => 'file',
        'weight' => JS_DEFAULT,
        'scope' => 'header',
        'cache' => TRUE,
        'defer' => FALSE,
        'preprocess' => TRUE,
        'data' => $data,
      );
    }
    
    /**
     * Returns a themed presentation of all JavaScript code for the current page.
     *
     * References to JavaScript files are placed in a certain order: first, all
     * 'core' files, then all 'module' and finally all 'theme' JavaScript files
     * are added to the page. Then, all settings are output, followed by 'inline'
     * JavaScript code. If running update.php, all preprocessing is disabled.
     *
     * Note that hook_js_alter(&$javascript) is called during this function call
     * to allow alterations of the JavaScript during its presentation. Calls to
     * drupal_add_js() from hook_js_alter() will not be added to the output
     * presentation. The correct way to add JavaScript during hook_js_alter()
     * is to add another element to the $javascript array, deriving from
     * drupal_js_defaults(). See locale_js_alter() for an example of this.
     *
     * @param $scope
     *   (optional) The scope for which the JavaScript rules should be returned.
     *   Defaults to 'header'.
     * @param $javascript
     *   (optional) An array with all JavaScript code. Defaults to the default
     *   JavaScript array for the given scope.
     * @return
     *   All JavaScript code segments and includes for the scope as HTML tags.
     * @see drupal_add_js()
     * @see locale_js_alter()
     * @see drupal_js_defaults()
     */
    function drupal_get_js($scope = 'header', $javascript = NULL) {
      if (!isset($javascript)) {
        $javascript = drupal_add_js();
      }
      if (empty($javascript)) {
        return '';
      }
    
      // Allow modules to alter the JavaScript.
      drupal_alter('js', $javascript);
    
      // Filter out elements of the given scope.
      $items = array();
      foreach ($javascript as $item) {
        if ($item['scope'] == $scope) {
          $items[] = $item;
        }
      }
    
      $output = '';
      $preprocessed = '';
      $no_preprocess = '';
      $files = array();
      $preprocess_js = (variable_get('preprocess_js', FALSE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update'));
      $directory = file_directory_path('public');
      $is_writable = is_dir($directory) && is_writable($directory);
    
      // A dummy query-string is added to filenames, to gain control over
      // browser-caching. The string changes on every update or full cache
      // flush, forcing browsers to load a new copy of the files, as the
      // URL changed. Files that should not be cached (see drupal_add_js())
      // get REQUEST_TIME as query-string instead, to enforce reload on every
      // page request.
      $query_string = '?' . substr(variable_get('css_js_query_string', '0'), 0, 1);
    
      // For inline Javascript to validate as XHTML, all Javascript containing
      // XHTML needs to be wrapped in CDATA. To make that backwards compatible
      // with HTML 4, we need to comment out the CDATA-tag.
      $embed_prefix = "\n<!--//--><![CDATA[//><!--\n";
      $embed_suffix = "\n//--><!]]>\n";
    
      // Sort the JavaScript by weight so that it appears in the correct order.
      uasort($items, 'drupal_sort_weight');
    
      // Loop through the JavaScript to construct the rendered output.
      foreach ($items as $item) {
        switch ($item['type']) {
          case 'setting':
            $output .= '<script type="text/javascript">' . $embed_prefix . 'jQuery.extend(Drupal.settings, ' . drupal_to_js(call_user_func_array('array_merge_recursive', $item['data'])) . ");" . $embed_suffix . "</script>\n";
            break;
    
          case 'inline':
            $output .= '<script type="text/javascript"' . ($item['defer'] ? ' defer="defer"' : '') . '>' . $embed_prefix . $item['data'] . $embed_suffix . "</script>\n";
            break;
    
          case 'file':
            if (!$item['preprocess'] || !$is_writable || !$preprocess_js) {
              $no_preprocess .= '<script type="text/javascript"' . ($item['defer'] ? ' defer="defer"' : '') . ' src="' . file_create_url($item['data']) . ($item['cache'] ? $query_string : '?' . REQUEST_TIME) . "\"></script>\n";
            }
            else {
              $files[$item['data']] = $item;
            }
            break;
    
          case 'external':
            // Preprocessing for external JavaScript files is ignored.
            $output .= '<script type="text/javascript"' . ($item['defer'] ? ' defer="defer"' : '') . ' src="' . check_plain($item['data']) . "\"></script>\n";
            break;
        }
      }
    
      // Aggregate any remaining JS files that haven't already been output.
      if ($is_writable && $preprocess_js && count($files) > 0) {
        // Prefix filename to prevent blocking by firewalls which reject files
        // starting with "ad*".
        $filename = 'js_' . md5(serialize($files) . $query_string) . '.js';
        $preprocess_file = file_create_url(drupal_build_js_cache($files, $filename));
        $preprocessed .= '<script type="text/javascript" src="' . $preprocess_file . '"></script>' . "\n";
      }
    
      // Keep the order of JS files consistent as some are preprocessed and others are not.
      // Make sure any inline or JS setting variables appear last after libraries have loaded.
      return $preprocessed . $no_preprocess . $output;
    }
    
    /**
     * Add to the page all structures attached to a render() structure.
     *
     * Libraries, JavaScript, CSS and other types of custom structures are attached
     * to elements using the #attached property. The #attached property contains an
     * associative array, where the keys are the the types of the structure, and
     * the value the attached data. For example:
     * @code
     * $build['#attached'] = array(
     *   'js' => array(drupal_get_path('module', 'taxonomy') . '/taxonomy.js'),
     *   'css' => array(drupal_get_path('module', 'taxonomy') . '/taxonomy.css'),
     * );
     * @endcode
     *
     * 'js', 'css', and 'library' are types that get special handling.  For any
     * other kind of attached data, the array key must be the full name of the
     * callback function and each value an array of arguments. For example:
     *
     * @code
     * $build['#attached']['drupal_set_header'] = array(
     *   array('Content-Type', 'application/rss+xml; charset=utf-8'),
     * );
     * @endcode
     *
     * @param $elements
     *   The structured array describing the data being rendered.
     * @param $weight
     *   The default weight of JavaScript and CSS being added. This is only applied
     *   to the stylesheets and JavaScript items that don't have an explicit weight
     *   assigned to them.
     * @param $dependency_check
     *   When TRUE, will exit if a given library's dependencies are missing. When
     *   set to FALSE, will continue to add the libraries, even though one of the
     *   dependencies are missing. Defaults to FALSE.
     * @return
     *   Will return FALSE if there were any missing library dependencies. TRUE will
     *   be returned if all library dependencies were met.
     *
     * @see drupal_add_library().
     * @see drupal_add_js().
     * @see drupal_add_css().
     * @see drupal_render().
     */
    function drupal_process_attached($elements, $weight = JS_DEFAULT, $dependency_check = FALSE) {
      // If there is nothing to process then return. 
      if (empty($elements['#attached'])) {
        return;
      }
      // Add defaults to the special attached structures that should be processed differently.
      $elements['#attached'] += array(
        'library' => array(),
        'js' => array(),
        'css' => array(),
      );
    
      // Add the libraries first.
      $success = TRUE;
      foreach ($elements['#attached']['library'] as $library) {
        if (drupal_add_library($library[0], $library[1]) === FALSE) {
          $success = FALSE;
          // Exit if the dependency is missing.
          if ($dependency_check) {
            return $success;
          }
        }
      }
      unset($elements['#attached']['library']);
    
      // Add both the JavaScript and the CSS.
      // The parameters for drupal_add_js() and drupal_add_css() require special
      // handling.
      foreach (array('js', 'css') as $type) {
        foreach ($elements['#attached'][$type] as $data => $options) {
          // If the value is not an array, it's a filename and passed as first
          // (and only) argument.
          if (!is_array($options)) {
            $data = $options;
            $options = NULL;
          }
          // In some cases, the first parameter ($data) is an array. Arrays can't be
          // passed as keys in PHP, so we have to get $data from the value array.
          if (is_numeric($data)) {
            $data = $options['data'];
            unset($options['data']);
          }
          // Apply the default weight if the weight isn't explicitly given.
          if (!isset($options['weight'])) {
            $options['weight'] = $weight;
          }
          call_user_func('drupal_add_' . $type, $data, $options);
        }
        unset($elements['#attached'][$type]);
      }
    
      // Add additional types of attachments specified in the render() structure.
      // Libraries, Javascript and CSS have been added already, as they require
      // special handling.
      foreach ($elements['#attached'] as $callback => $options) {
        if (function_exists($callback)) {
          foreach ($elements['#attached'][$callback] as $args) {
            call_user_func_array($callback, $args);
          }
        }
      }
    
      return $success;
    }
    
    /**
     * Adds multiple JavaScript or CSS files at the same time.
     *
     * A library defines a set of JavaScript and/or CSS files, optionally using
     * settings, and optionally requiring another library. For example, a library
     * can be a jQuery plugin, a JavaScript framework, or a CSS framework. This
     * function allows modules to load a library defined/shipped by itself or a
     * depending module; without having to add all files of the library separately.
     * Each library is only loaded once.
     *
     * @param $module
     *   The name of the module that registered the library.
     * @param $name
     *   The name of the library to add.
     * @return
     *   TRUE when the library was successfully added or FALSE if the library or one
     *   of its dependencies could not be added.
     *
     * @see drupal_get_library()
     * @see hook_library()
     * @see hook_library_alter()
     */
    function drupal_add_library($module, $name) {
      $added = &drupal_static(__FUNCTION__, array());
    
      // Only process the library if it exists and it was not added already.
      if (!isset($added[$module][$name])) {
        if ($library = drupal_get_library($module, $name)) {
          // Add all components within the library.
          $elements['#attached'] = array(
            'library' => $library['dependencies'],
            'js' => $library['js'],
            'css' => $library['css'],
          );
          $added[$module][$name] = drupal_process_attached($elements, JS_LIBRARY, TRUE);
        }
        else {
          // Requested library does not exist.
          $added[$module][$name] = FALSE;
        }
      }
    
      return $added[$module][$name];
    }
    
    /**
     * Retrieves information for a JavaScript/CSS library.
     *
     * Library information is statically cached. Libraries are keyed by module for
     * several reasons:
     * - Libraries are not unique. Multiple modules might ship with the same library
     *   in a different version or variant. This registry cannot (and does not
     *   attempt to) prevent library conflicts.
     * - Modules implementing and thereby depending on a library that is registered
     *   by another module can only rely on that module's library.
     * - Two (or more) modules can still register the same library and use it
     *   without conflicts in case the libraries are loaded on certain pages only.
     *
     * @param $module
     *   The name of a module that registered a library.
     * @param $library
     *   The name of a registered library.
     * @return
     *   The definition of the requested library, if existent, or FALSE.
     *
     * @see drupal_add_library()
     * @see hook_library()
     * @see hook_library_alter()
     *
     * @todo The purpose of drupal_get_*() is completely different to other page
     *   requisite API functions; find and use a different name.
     */
    function drupal_get_library($module, $name) {
      $libraries = &drupal_static(__FUNCTION__, array());
    
      if (!array_key_exists($module, $libraries)) {
        // Retrieve all libraries associated with the module.
        $module_libraries = module_invoke($module, 'library');
    
        // Allow modules to alter the module's registered libraries.
        if (!empty($module_libraries)) {
          drupal_alter('library', $module_libraries, $module);
        }
        $libraries[$module] = $module_libraries;
      }
      if (!empty($libraries[$module][$name]) && is_array($libraries[$module][$name])) {
        // Add default elements to allow for easier processing.
        $libraries[$module][$name] += array('dependencies' => array(), 'js' => array(), 'css' => array());
      }
      else {
        $libraries[$module][$name] = FALSE;
      }
    
      return $libraries[$module][$name];
    }
    
    /**
     * Assist in adding the tableDrag JavaScript behavior to a themed table.
     *
     * Draggable tables should be used wherever an outline or list of sortable items
     * needs to be arranged by an end-user. Draggable tables are very flexible and
     * can manipulate the value of form elements placed within individual columns.
     *
     * To set up a table to use drag and drop in place of weight select-lists or
     * in place of a form that contains parent relationships, the form must be
     * themed into a table. The table must have an id attribute set. If using
     * theme_table(), the id may be set as such:
     * @code
     * $output = theme('table', $header, $rows, array('id' => 'my-module-table'));
     * return $output;
     * @endcode
     *
     * In the theme function for the form, a special class must be added to each
     * form element within the same column, "grouping" them together.
     *
     * In a situation where a single weight column is being sorted in the table, the
     * classes could be added like this (in the theme function):
     * @code
     * $form['my_elements'][$delta]['weight']['#attributes']['class'] = array('my-elements-weight');
     * @endcode
     *
     * Each row of the table must also have a class of "draggable" in order to enable the
     * drag handles:
     * @code
     * $row = array(...);
     * $rows[] = array(
     *   'data' => $row,
     *   'class' => array('draggable'),
     * );
     * @endcode
     *
     * When tree relationships are present, the two additional classes
     * 'tabledrag-leaf' and 'tabledrag-root' can be used to refine the behavior:
     * - Rows with the 'tabledrag-leaf' class cannot have child rows.
     * - Rows with the 'tabledrag-root' class cannot be nested under a parent row.
     *
     * Calling drupal_add_tabledrag() would then be written as such:
     * @code
     * drupal_add_tabledrag('my-module-table', 'order', 'sibling', 'my-elements-weight');
     * @endcode
     *
     * In a more complex case where there are several groups in one column (such as
     * the block regions on the admin/structure/block page), a separate subgroup class
     * must also be added to differentiate the groups.
     * @code
     * $form['my_elements'][$region][$delta]['weight']['#attributes']['class'] = array('my-elements-weight', 'my-elements-weight-' . $region);
     * @endcode
     *
     * $group is still 'my-element-weight', and the additional $subgroup variable
     * will be passed in as 'my-elements-weight-' . $region. This also means that
     * you'll need to call drupal_add_tabledrag() once for every region added.
     *
     * @code
     * foreach ($regions as $region) {
     *   drupal_add_tabledrag('my-module-table', 'order', 'sibling', 'my-elements-weight', 'my-elements-weight-' . $region);
     * }
     * @endcode
     *
     * In a situation where tree relationships are present, adding multiple
     * subgroups is not necessary, because the table will contain indentations that
     * provide enough information about the sibling and parent relationships.
     * See theme_menu_overview_form() for an example creating a table containing
     * parent relationships.
     *
     * Please note that this function should be called from the theme layer, such as
     * in a .tpl.php file, theme_ function, or in a template_preprocess function,
     * not in a form declaration. Though the same JavaScript could be added to the
     * page using drupal_add_js() directly, this function helps keep template files
     * clean and readable. It also prevents tabledrag.js from being added twice
     * accidentally.
     *
     * @param $table_id
     *   String containing the target table's id attribute. If the table does not
     *   have an id, one will need to be set, such as <table id="my-module-table">.
     * @param $action
     *   String describing the action to be done on the form item. Either 'match'
     *   'depth', or 'order'. Match is typically used for parent relationships.
     *   Order is typically used to set weights on other form elements with the same
     *   group. Depth updates the target element with the current indentation.
     * @param $relationship
     *   String describing where the $action variable should be performed. Either
     *   'parent', 'sibling', 'group', or 'self'. Parent will only look for fields
     *   up the tree. Sibling will look for fields in the same group in rows above
     *   and below it. Self affects the dragged row itself. Group affects the
     *   dragged row, plus any children below it (the entire dragged group).
     * @param $group
     *   A class name applied on all related form elements for this action.
     * @param $subgroup
     *   (optional) If the group has several subgroups within it, this string should
     *   contain the class name identifying fields in the same subgroup.
     * @param $source
     *   (optional) If the $action is 'match', this string should contain the class
     *   name identifying what field will be used as the source value when matching
     *   the value in $subgroup.
     * @param $hidden
     *   (optional) The column containing the field elements may be entirely hidden
     *   from view dynamically when the JavaScript is loaded. Set to FALSE if the
     *   column should not be hidden.
     * @param $limit
     *   (optional) Limit the maximum amount of parenting in this table.
     * @see block-admin-display-form.tpl.php
     * @see theme_menu_overview_form()
     */
    function drupal_add_tabledrag($table_id, $action, $relationship, $group, $subgroup = NULL, $source = NULL, $hidden = TRUE, $limit = 0) {
      $js_added = &drupal_static(__FUNCTION__, FALSE);
      if (!$js_added) {
        // Add the table drag JavaScript to the page before the module JavaScript
        // to ensure that table drag behaviors are registered before any module
        // uses it.
        drupal_add_js('misc/tabledrag.js', array('weight' => JS_DEFAULT - 1));
        $js_added = TRUE;
      }
    
      // If a subgroup or source isn't set, assume it is the same as the group.
      $target = isset($subgroup) ? $subgroup : $group;
      $source = isset($source) ? $source : $target;
      $settings['tableDrag'][$table_id][$group][] = array(
        'target' => $target,
        'source' => $source,
        'relationship' => $relationship,
        'action' => $action,
        'hidden' => $hidden,
        'limit' => $limit,
      );
      drupal_add_js($settings, 'setting');
    }
    
    /**
     * Aggregate JS files, putting them in the files directory.
     *
     * @param $files
     *   An array of JS files to aggregate and compress into one file.
     * @param $filename
     *   The name of the aggregate JS file.
     * @return
     *   The name of the JS file.
     */
    function drupal_build_js_cache($files, $filename) {
      $contents = '';
    
      // Create the js/ within the files folder.
      $jspath = 'public://js';
      file_prepare_directory($jspath, FILE_CREATE_DIRECTORY);
    
      if (!file_exists($jspath . '/' . $filename)) {
        // Build aggregate JS file.
        foreach ($files as $path => $info) {
          if ($info['preprocess']) {
            // Append a ';' after each JS file to prevent them from running together.
            $contents .= file_get_contents($path) . ';';
          }
        }
    
        // Create the JS file.
        file_unmanaged_save_data($contents, $jspath . '/' . $filename, FILE_EXISTS_REPLACE);
      }
    
      return $jspath . '/' . $filename;
    }
    
    /**
     * Delete all cached JS files.
     */
    function drupal_clear_js_cache() {
      file_scan_directory('public://js', '/.*/', array('callback' => 'file_unmanaged_delete'));
      variable_set('javascript_parsed', array());
    }
    
    /**
     * Converts a PHP variable into its Javascript equivalent.
     *
     * We use HTML-safe strings, i.e. with <, > and & escaped.
     */
    function drupal_to_js($var) {
      // json_encode() does not escape <, > and &, so we do it with str_replace()
      return str_replace(array("<", ">", "&"), array('\x3c', '\x3e', '\x26'), json_encode($var));
    }
    
    /**
     * Return data in JSON format.
     *
     * This function should be used for JavaScript callback functions returning
     * data in JSON format. It sets the header for JavaScript output.
     *
     * @param $var
     *   (optional) If set, the variable will be converted to JSON and output.
     */
    function drupal_json($var = NULL) {
      // We are returning JavaScript, so tell the browser.
      drupal_set_header('Content-Type', 'text/javascript; charset=utf-8');
    
      if (isset($var)) {
        echo drupal_to_js($var);
      }
    }
    
    /**
     * Wrapper around urlencode() which avoids Apache quirks.
     *
     * Should be used when placing arbitrary data in an URL. Note that Drupal paths
     * are urlencoded() when passed through url() and do not require urlencoding()
     * of individual components.
     *
     * Notes:
     * - For esthetic reasons, we do not escape slashes. This also avoids a 'feature'
     *   in Apache where it 404s on any path containing '%2F'.
     * - mod_rewrite unescapes %-encoded ampersands, hashes, and slashes when clean
     *   URLs are used, which are interpreted as delimiters by PHP. These
     *   characters are double escaped so PHP will still see the encoded version.
     * - With clean URLs, Apache changes '//' to '/', so every second slash is
     *   double escaped.
     * - This function should only be used on paths, not on query string arguments,
     *   otherwise unwanted double encoding will occur.
     *
     * @param $text
     *   String to encode
     */
    function drupal_encode_path($text) {
      if (variable_get('clean_url', '0')) {
        return str_replace(array('%2F', '%26', '%23', '//'),
                            array('/', '%2526', '%2523', '/%252F'),
                            rawurlencode($text));
      }
      else {
        return str_replace('%2F', '/', rawurlencode($text));
      }
    }
    
    /**
     * Returns a string of highly randomized bytes (over the full 8-bit range).
     *
     * This function is better than simply calling mt_rand() or any other built-in
     * PHP function because it can return a long string of bytes (compared to < 4
     * bytes normally from mt_rand()) and uses the best available pseudo-random source.
     *
     * @param $count
     *   The number of characters (bytes) to return in the string.
     */
    function drupal_random_bytes($count)  {
      // $random_state does not use drupal_static as it stores random bytes.
      static $random_state;
      // We initialize with the somewhat random PHP process ID on the first call.
      if (empty($random_state)) {
        $random_state = getmypid();
      }
      $output = '';
      // /dev/urandom is available on many *nix systems and is considered the best
      // commonly available pseudo-random source.
      if ($fh = @fopen('/dev/urandom', 'rb')) {
        $output = fread($fh, $count);
        fclose($fh);
      }
      // If /dev/urandom is not available or returns no bytes, this loop will
      // generate a good set of pseudo-random bytes on any system.
      // Note that it may be important that our $random_state is passed
      // through md5() prior to being rolled into $output, that the two md5()
      // invocations are different, and that the extra input into the first one -
      // the microtime() - is prepended rather than appended. This is to avoid
      // directly leaking $random_state via the $output stream, which could
      // allow for trivial prediction of further "random" numbers.
      while (strlen($output) < $count) {
        $random_state = md5(microtime() . mt_rand() . $random_state);
        $output .= md5(mt_rand() . $random_state, TRUE);
      }
      return substr($output, 0, $count);
    }
    
    /**
     * Ensure the private key variable used to generate tokens is set.
     *
     * @return
     *   The private key.
     */
    function drupal_get_private_key() {
      if (!($key = variable_get('drupal_private_key', 0))) {
        $key = md5(drupal_random_bytes(64));
        variable_set('drupal_private_key', $key);
      }
      return $key;
    }
    
    /**
     * Generate a token based on $value, the current user session and private key.
     *
     * @param $value
     *   An additional value to base the token on.
     */
    function drupal_get_token($value = '') {
      $private_key = drupal_get_private_key();
      return md5(session_id() . $value . $private_key);
    }
    
    /**
     * Validate a token based on $value, the current user session and private key.
     *
     * @param $token
     *   The token to be validated.
     * @param $value
     *   An additional value to base the token on.
     * @param $skip_anonymous
     *   Set to true to skip token validation for anonymous users.
     * @return
     *   True for a valid token, false for an invalid token. When $skip_anonymous
     *   is true, the return value will always be true for anonymous users.
     */
    function drupal_valid_token($token, $value = '', $skip_anonymous = FALSE) {
      global $user;
      return (($skip_anonymous && $user->uid == 0) || ($token == md5(session_id() . $value . variable_get('drupal_private_key', ''))));
    }
    
    function _drupal_bootstrap_full() {
      $called = &drupal_static(__FUNCTION__);
    
      if ($called) {
        return;
      }
      $called = 1;
      require_once DRUPAL_ROOT . '/includes/theme.inc';
      require_once DRUPAL_ROOT . '/includes/pager.inc';
      require_once DRUPAL_ROOT . '/includes/menu.inc';
      require_once DRUPAL_ROOT . '/includes/tablesort.inc';
      require_once DRUPAL_ROOT . '/includes/file.inc';
      require_once DRUPAL_ROOT . '/includes/unicode.inc';
      require_once DRUPAL_ROOT . '/includes/image.inc';
      require_once DRUPAL_ROOT . '/includes/form.inc';
      require_once DRUPAL_ROOT . '/includes/mail.inc';
      require_once DRUPAL_ROOT . '/includes/actions.inc';
      require_once DRUPAL_ROOT . '/includes/ajax.inc';
      require_once DRUPAL_ROOT . '/includes/token.inc';
      // Set the Drupal custom error handler.
      set_error_handler('_drupal_error_handler');
      set_exception_handler('_drupal_exception_handler');
    
      // Emit the correct charset HTTP header.
      drupal_set_header('Content-Type', 'text/html; charset=utf-8');
      // Detect string handling method
      unicode_check();
      // Undo magic quotes
      fix_gpc_magic();
      // Load all enabled modules
      module_load_all();
      // Make sure all stream wrappers are registered.
      file_get_stream_wrappers();
      if (isset($_SERVER['HTTP_USER_AGENT']) && strpos($_SERVER['HTTP_USER_AGENT'], 'simpletest') !== FALSE) {
        // Valid SimpleTest user-agent, log fatal errors to test specific file
        // directory. The user-agent is validated in DRUPAL_BOOTSTRAP_DATABASE
        // phase so as long as it is a SimpleTest user-agent it is valid.
        ini_set('log_errors', 1);
        ini_set('error_log', file_directory_path() . '/error.log');
      }
    
      // Let all modules take action before menu system handles the request
      // We do not want this while running update.php.
      if (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update') {
        module_invoke_all('init');
      }
    }
    
    /**
     * Store the current page in the cache.
     *
     * We try to store a gzipped version of the cache. This requires the
     * PHP zlib extension (http://php.net/manual/en/ref.zlib.php).
     * Presence of the extension is checked by testing for the function
     * gzencode. There are two compression algorithms: gzip and deflate.
     * The majority of all modern browsers support gzip or both of them.
     * We thus only deal with the gzip variant and unzip the cache in case
     * the browser does not accept gzip encoding.
     *
     * @see drupal_page_header
     */
    function drupal_page_set_cache() {
      global $base_root;
    
      if (drupal_page_is_cacheable()) {
        $cache_page = TRUE;
    
        $cache = (object) array(
          'cid' => $base_root . request_uri(),
          'data' => ob_get_clean(),
          'expire' => CACHE_TEMPORARY,
          'created' => REQUEST_TIME,
          'headers' => array(),
        );
    
        // Restore preferred header names based on the lower-case names returned
        // by drupal_get_header().
        $header_names = _drupal_set_preferred_header_name();
        foreach (drupal_get_header() as $name_lower => $value) {
          $cache->headers[$header_names[$name_lower]] = $value;
        }
    
        if (variable_get('page_compression', TRUE) && function_exists('gzencode')) {
          // We do not store the data in case the zlib mode is deflate. This should
          // be rarely happening.
          if (zlib_get_coding_type() == 'deflate') {
            $cache_page = FALSE;
          }
          elseif (zlib_get_coding_type() == FALSE) {
            $cache->data = gzencode($cache->data, 9, FORCE_GZIP);
          }
          // The remaining case is 'gzip' which means the data is already
          // compressed and nothing left to do but to store it.
        }
        if ($cache_page && $cache->data) {
          cache_set($cache->cid, $cache->data, 'cache_page', $cache->expire, $cache->headers);
        }
        return $cache;
      }
    }
    
    /**
     * Executes a cron run when called
     * @return
     * Returns TRUE if ran successfully
     */
    function drupal_cron_run() {
      // Allow execution to continue even if the request gets canceled.
      @ignore_user_abort(TRUE);
    
      // Try to allocate enough time to run all the hook_cron implementations.
      drupal_set_time_limit(240);
    
      // Fetch the cron semaphore
      $semaphore = variable_get('cron_semaphore', FALSE);
    
      if ($semaphore) {
        if (REQUEST_TIME - $semaphore > 3600) {
          // Either cron has been running for more than an hour or the semaphore
          // was not reset due to a database error.
          watchdog('cron', 'Cron has been running for more than an hour and is most likely stuck.', array(), WATCHDOG_ERROR);
    
          // Release cron semaphore
          variable_del('cron_semaphore');
        }
        else {
          // Cron is still running normally.
          watchdog('cron', 'Attempting to re-run cron while it is already running.', array(), WATCHDOG_WARNING);
        }
      }
      else {
        // Register shutdown callback
        register_shutdown_function('drupal_cron_cleanup');
    
        // Lock cron semaphore
        variable_set('cron_semaphore', REQUEST_TIME);
    
        // Iterate through the modules calling their cron handlers (if any):
        module_invoke_all('cron');
    
        // Record cron time
        variable_set('cron_last', REQUEST_TIME);
        watchdog('cron', 'Cron run completed.', array(), WATCHDOG_NOTICE);
    
        // Release cron semaphore
        variable_del('cron_semaphore');
    
        // Return TRUE so other functions can check if it did run successfully
        return TRUE;
      }
    }
    
    /**
     * Shutdown function for cron cleanup.
     */
    function drupal_cron_cleanup() {
      // See if the semaphore is still locked.
      if (variable_get('cron_semaphore', FALSE)) {
        watchdog('cron', 'Cron run exceeded the time limit and was aborted.', array(), WATCHDOG_WARNING);
    
        // Release cron semaphore
        variable_del('cron_semaphore');
      }
    }
    
    /**
     * Return an array of system file objects.
     *
     * Returns an array of file objects of the given type from the site-wide
     * directory (i.e. modules/), the all-sites directory (i.e.
     * sites/all/modules/), the profiles directory, and site-specific directory
     * (i.e. sites/somesite/modules/). The returned array will be keyed using the
     * key specified (name, basename, filename). Using name or basename will cause
     * site-specific files to be prioritized over similar files in the default
     * directories. That is, if a file with the same name appears in both the
     * site-wide directory and site-specific directory, only the site-specific
     * version will be included.
     *
     * @param $mask
     *   The preg_match() regular expression of the files to find.
     * @param $directory
     *   The subdirectory name in which the files are found. For example,
     *   'modules' will search in both modules/ and
     *   sites/somesite/modules/.
     * @param $key
     *   The key to be passed to file_scan_directory().
     * @param $min_depth
     *   Minimum depth of directories to return files from.
     *
     * @return
     *   An array of file objects of the specified type.
     */
    function drupal_system_listing($mask, $directory, $key = 'name', $min_depth = 1) {
      $config = conf_path();
    
      $profile = drupal_get_profile();
    
      $searchdir = array($directory);
      $files = array();
    
      // The 'profiles' directory contains pristine collections of modules and
      // themes as organized by a distribution. It is pristine in the same way
      // that /modules is pristine for core; users should avoid changing anything
      // there in favor of sites/all or sites/<domain> directories.
      if (file_exists("profiles/$profile/$directory")) {
        $searchdir[] = "profiles/$profile/$directory";
      }
    
      // Always search sites/all/* as well as the global directories
      $searchdir[] = 'sites/all/' . $directory;
    
      if (file_exists("$config/$directory")) {
        $searchdir[] = "$config/$directory";
      }
    
      // If the database is not available, we can't use function_exists(), so
      // we load the file_scan_directory function definition manually.
      if (!function_exists('file_scan_directory')) {
        require_once DRUPAL_ROOT . '/includes/file.inc';
      }
    
      // Get current list of items
      foreach ($searchdir as $dir) {
        $files = array_merge($files, file_scan_directory($dir, $mask, array('key' => $key, 'min_depth' => $min_depth)));
      }
    
      return $files;
    }
    
    /**
     * Hands off structured Drupal arrays to type-specific *_alter implementations.
     *
     * This dispatch function hands off structured Drupal arrays to type-specific
     * *_alter implementations. It ensures a consistent interface for all altering
     * operations.
     *
     * @param $type
     *   The data type of the structured array. 'form', 'links',
     *   'node_content', and so on are several examples.
     * @param $data
     *   The structured array to be altered.
     * @param ...
     *   Any additional params will be passed on to the called
     *   hook_$type_alter functions.
     */
    function drupal_alter($type, &$data) {
      // PHP's func_get_args() always returns copies of params, not references, so
      // drupal_alter() can only manipulate data that comes in via the required first
      // param. For the edge case functions that must pass in an arbitrary number of
      // alterable parameters (hook_form_alter() being the best example), an array of
      // those params can be placed in the __drupal_alter_by_ref key of the $data
      // array. This is somewhat ugly, but is an unavoidable consequence of a flexible
      // drupal_alter() function, and the limitations of func_get_args().
      // @todo: Remove this in Drupal 7.
      if (is_array($data) && isset($data['__drupal_alter_by_ref'])) {
        $by_ref_parameters = $data['__drupal_alter_by_ref'];
        unset($data['__drupal_alter_by_ref']);
      }
    
      // Hang onto a reference to the data array so that it isn't blown away later.
      // Also, merge in any parameters that need to be passed by reference.
      $args = array(&$data);
      if (isset($by_ref_parameters)) {
        $args = array_merge($args, $by_ref_parameters);
      }
    
      // Now, use func_get_args() to pull in any additional parameters passed into
      // the drupal_alter() call.
      $additional_args = func_get_args();
      array_shift($additional_args);
      array_shift($additional_args);
      $args = array_merge($args, $additional_args);
    
      foreach (module_implements($type . '_alter') as $module) {
        $function = $module . '_' . $type . '_alter';
        call_user_func_array($function, $args);
      }
    }
    
    /**
     * Set the main page content value for later use.
     *
     * Given the nature of the Drupal page handling, this will be called once with
     * a string or array. We store that and return it later as the block is being
     * displayed.
     *
     * @param $content
     *   A string or renderable array representing the body of the page.
     * @return
     *   A renderable array representing the body of the page.
     */
    function drupal_set_page_content($content = NULL) {
      $content_block = &drupal_static(__FUNCTION__, NULL);
      if (!empty($content)) {
        $content_block = (is_array($content) ? $content : array('main' => array('#markup' => $content)));
      }
      else {
        return $content_block;
      }
    }
    
    /**
     * Renders the page, including all theming.
     *
     * @param $page
     *   A string or array representing the content of a page. The array consists of
     *   the following keys:
     *   - #type: Value is always 'page'. This pushes the theming through page.tpl.php (required).
     *   - #show_messages: Suppress drupal_get_message() items. Used by Batch API (optional).
     *
     * @see hook_page_alter()
     * @see element_info('page')
     */
    function drupal_render_page($page) {
      // Allow menu callbacks to return strings or arbitrary arrays to render.
      // If the array returned is not of #type page directly, we need to fill
      // in the page with defaults.
      if (is_string($page) || (is_array($page) && (!isset($page['#type']) || ($page['#type'] != 'page')))) {
        drupal_set_page_content($page);
        $page = element_info('page');
      }
    
      // Modules can add elements to $page as needed in hook_page_build().
      foreach (module_implements('page_build') as $module) {
        $function = $module . '_page_build';
        $function($page);
      }
      // Modules alter the $page as needed. Blocks are populated into regions like
      // 'sidebar_first', 'footer', etc.
      drupal_alter('page', $page);
    
      return drupal_render($page);
    }
    
    /**
     * Renders HTML given a structured array tree.
     *
     * Recursively iterates over each of the array elements, generating HTML code.
     *
     * HTML generation is controlled by two properties containing theme functions,
     * #theme and #theme_wrappers.
     *
     * #theme is the theme function called first. If it is set and the element has
     * any children, they have to be rendered there. For elements that are not
     * allowed to have any children, e.g. buttons or textfields, it can be used to
     * render the element itself. If #theme is not present and the element has
     * children, they are rendered and concatenated into a string by
     * drupal_render_children().
     *
     * The #theme_wrappers property contains an array of theme functions which will
     * be called, in order, after #theme has run. These can be used to add further
     * markup around the rendered children; e.g., fieldsets add the required markup
     * for a fieldset around their rendered child elements. All wrapper theme
     * functions have to include the element's #children property in their output,
     * as it contains the output of the previous theme functions and the rendered
     * children.
     *
     * For example, for the form element type, by default only the #theme_wrappers
     * property is set, which adds the form markup around the rendered child
     * elements of the form. This allows you to set the #theme property on a
     * specific form to a custom theme function, giving you complete control over
     * the placement of the form's children while not at all having to deal with
     * the form markup itself.
     *
     * drupal_render() can optionally cache the rendered output of elements to
     * improve performance. To use drupal_render() caching, set the element's #cache
     * property to an associative array with one or several of the following keys:
     *    - 'keys': An array of one or more keys that identify the element. If 'keys'
     *       is set, the cache ID is created automatically from these keys.
     *       @see drupal_render_cid_create()
     *    - 'granularity' (optional): Define the cache granularity using binary
     *       combinations of the cache granularity constants, e.g. DRUPAL_CACHE_PER_USER
     *       to cache for each user seperately or
     *       DRUPAL_CACHE_PER_PAGE | DRUPAL_CACHE_PER_ROLE to cache seperately for each
     *       page and role. If not specified the element is cached globally for each
     *       theme and language.
     *    - 'cid': Specify the cache ID directly. Either 'keys' or 'cid' is required.
     *       If 'cid' is set, 'keys' and 'granularity' are ignored. Use only if you
     *       have special requirements.
     *    - 'expire': Set to one of the cache lifetime constants.
     *    - 'bin': Specify a cache bin to cache the element in. Defaults to 'cache'.
     *
     * This function is usually called from within another function, like
     * drupal_get_form() or a theme function. Elements are sorted internally
     * using uasort(). Since this is expensive, when passing already sorted
     * elements to drupal_render(), for example from a database query, set
     * $elements['#sorted'] = TRUE to avoid sorting them a second time.
     *
     * @param $elements
     *   The structured array describing the data to be rendered.
     * @return
     *   The rendered HTML.
     */
    function drupal_render(&$elements) {
      static $defaults;
      // Early-return nothing if user does not have access.
      if (!isset($elements) || (isset($elements['#access']) && !$elements['#access'])) {
        return;
      }
    
      // Do not print elements twice.
      if (isset($elements['#printed']) && $elements['#printed']) {
        return;
      }
    
      // Try to fetch the element's markup from cache and return.
      if (isset($elements['#cache']) && $cached_output = drupal_render_cache_get($elements)) {
        return $cached_output;
      }
    
      // If the default values for this element have not been loaded yet, populate
      // them.
      if (isset($elements['#type']) && empty($elements['#defaults_loaded'])) {
        $elements += element_info($elements['#type']);
      }
      else {
        if (!isset($defaults)) {
          $defaults = element_basic_defaults();
        }
        $elements += $defaults;
      }
    
      // If #markup is not empty and no theme function is set, use theme_markup.
      // This allows to specify just #markup on an element without setting the #type.
      if (!empty($elements['#markup']) && empty($elements['#theme'])) {
        $elements['#theme'] = 'markup';
      }
    
      // Make any final changes to the element before it is rendered. This means
      // that the $element or the children can be altered or corrected before the
      // element is rendered into the final text.
      if (isset($elements['#pre_render'])) {
        foreach ($elements['#pre_render'] as $function) {
          if (function_exists($function)) {
            $elements = $function($elements);
          }
        }
      }
    
      // Get the children of the element, sorted by weight.
      $children = element_children($elements, TRUE);
    
      $elements['#children'] = '';
      // Call the element's #theme function if it is set. Then any children of the
      // element have to be rendered there.
      if (isset($elements['#theme'])) {
        $elements['#children'] = theme($elements['#theme'], $elements);
      }
      // If #theme was not set and the element has children, render them now
      // using drupal_render_children().
      if ($elements['#children'] == '') {
        $elements['#children'] = drupal_render_children($elements, $children);
      }
    
      // Let the theme functions in #theme_wrappers add markup around the rendered
      // children.
      if (isset($elements['#theme_wrappers'])) {
        foreach ($elements['#theme_wrappers'] as $theme_wrapper) {
          $elements['#children'] = theme($theme_wrapper, $elements);
        }
      }
    
      // Filter the outputted content and make any last changes before the
      // content is sent to the browser. The changes are made on $content
      // which allows the output'ed text to be filtered.
      if (isset($elements['#post_render'])) {
        foreach ($elements['#post_render'] as $function) {
          if (function_exists($function)) {
            $elements['#children'] = $function($elements['#children'], $elements);
          }
        }
      }
    
      // Add additional libraries, CSS, JavaScript an other custom
      // attached data associated with this element.
      drupal_process_attached($elements);
    
      $prefix = isset($elements['#prefix']) ? $elements['#prefix'] : '';
      $suffix = isset($elements['#suffix']) ? $elements['#suffix'] : '';
    
      // Cache the processed element if #cache is set.
      if (isset($elements['#cache'])) {
        drupal_render_cache_set($prefix . $elements['#children'] . $suffix, $elements);
      }
    
      $elements['#printed'] = TRUE;
      return $prefix . $elements['#children'] . $suffix;
    }
    
    /**
     * Render children of an element and concatenate them.
     *
     * This renders all children of an element using drupal_render() and then
     * joins them together into a single string.
     *
     * @param $element
     *   The structured array whose children shall be rendered.
     * @param $children_keys
     *   If the keys of the element's children are already known, they can be passed
     *   in to save another run of element_children().
     */
    function drupal_render_children(&$element, $children_keys = NULL) {
      if ($children_keys === NULL) {
        $children_keys = element_children($element);
      }
      $output = '';
      foreach ($children_keys as $key) {
        $output .= drupal_render($element[$key]);
      }
      return $output;
    }
    
    /**
     * Render and print an element.
     *
     * This function renders an element using drupal_render(). The top level
     * element is always rendered even if hide() had been previously used on it.
     *
     * Any nested elements are only rendered if they haven't been rendered before
     * or if they have been re-enabled with show().
     *
     * @see drupal_render()
     * @see show()
     * @see hide()
     */
    function render(&$element) {
      if (is_array($element)) {
        show($element);
        return drupal_render($element);
      }
      else {
        // Safe-guard for inappropriate use of render() on flat variables: return
        // the variable as-is.
        return $element;
      }
    }
    
    /**
     * Hide an element from later rendering.
     *
     * @see render()
     * @see show()
     */
    function hide(&$element) {
      $element['#printed'] = TRUE;
      return $element;
    }
    
    /**
     * Show a hidden or already printed element from later rendering.
     *
     * Alternatively, render($element) could be used which automatically shows the
     * element while rendering it.
     *
     * @see render()
     * @see hide()
     */
    function show(&$element) {
      $element['#printed'] = FALSE;
      return $element;
    }
    
    /**
     * Get the rendered output of a renderable element from cache.
     *
     * @see drupal_render()
     * @see drupal_render_cache_set()
     * 
     * @param $elements
     *   A renderable array.
     * @return
     *   A markup string containing the rendered content of the element, or FALSE
     *   if no cached copy of the element is available.
     */
    function drupal_render_cache_get($elements) {
      if (!in_array($_SERVER['REQUEST_METHOD'], array('GET', 'HEAD')) || !$cid = drupal_render_cid_create($elements)) {
        return FALSE;
      }
      $bin = isset($elements['#cache']['bin']) ? $elements['#cache']['bin'] : 'cache';
    
      if (!empty($cid) && $cache = cache_get($cid, $bin)) {
        // Add additional libraries, JavaScript, CSS and other data attached
        // to this element.
        drupal_process_attached($cache->data);
        // Return the rendered output.
        return $cache->data['#markup'];;
      }
      return FALSE;
    }
    
    /**
     * Cache the rendered output of a renderable element.
     *
     * This is called by drupal_render() if the #cache property is set on an element.
     *
     * @see drupal_render()
     * @see drupal_render_cache_get()
     *
     * @param $markup
     *   The rendered output string of $elements.
     * @param $elements
     *   A renderable array.
     */
    function drupal_render_cache_set($markup, $elements) {
      // Create the cache ID for the element 
      if (!in_array($_SERVER['REQUEST_METHOD'], array('GET', 'HEAD')) || !$cid = drupal_render_cid_create($elements)) {
        return FALSE;
      }
    
      $data['#markup'] = $markup;
      // Persist attached data associated with this element.
      $data['#attached'] = $elements['#attached'];
      $bin = isset($elements['#cache']['bin']) ? $elements['#cache']['bin'] : 'cache';
      $expire = isset($elements['#cache']['expire']) ? $elements['#cache']['expire'] : CACHE_PERMANENT;
      cache_set($cid, $data, $bin, $expire);
    }
    
    /**
     * Helper function for building cache ids.
     *
     * @param $granularity
     *   One or more cache granularity constants, e.g. DRUPAL_CACHE_PER_USER to cache
     *   for each user seperately or DRUPAL_CACHE_PER_PAGE | DRUPAL_CACHE_PER_ROLE to
     *   cache seperately for each page and role.
     *
     * @return
     *   An array of cache ID parts, always containing the active theme. If the
     *   locale module is enabled it also contains the active language. If
     *   $granularity was passed in, more parts are added.
     */
    function drupal_render_cid_parts($granularity = NULL) {
      global $theme, $base_root, $user;
    
      $cid_parts[] = $theme;
      if (module_exists('locale')) {
        global $language;
        $cid_parts[] = $language->language;
      }
    
      if (!empty($granularity)) {
        // 'PER_ROLE' and 'PER_USER' are mutually exclusive. 'PER_USER' can be a
        // resource drag for sites with many users, so when a module is being
        // equivocal, we favor the less expensive 'PER_ROLE' pattern.
        if ($granularity & DRUPAL_CACHE_PER_ROLE) {
          $cid_parts[] = 'r.' . implode(',', array_keys($user->roles));
        }
        elseif ($granularity & DRUPAL_CACHE_PER_USER) {
          $cid_parts[] = "u.$user->uid";
        }
    
        if ($granularity & DRUPAL_CACHE_PER_PAGE) {
          $cid_parts[] = $base_root . request_uri();
        }
      }
    
      return $cid_parts;
    }
    
    /**
     * Create the cache ID for a renderable element.
     *
     * This creates the cache ID string, either by returning the #cache['cid']
     * property if present or by building the cache ID out of the #cache['keys']
     * and, optionally, the #cache['granularity'] properties.
     *
     * @param $elements
     *   A renderable array.
     *
     * @return
     *   The cache ID string, or FALSE if the element may not be cached.
     */
    function drupal_render_cid_create($elements) {
      if (isset($elements['#cache']['cid'])) {
        return $elements['#cache']['cid'];
      }
      elseif (isset($elements['#cache']['keys'])) {
        $granularity = isset($elements['#cache']['granularity']) ? $elements['#cache']['granularity'] : NULL;
        // Merge in additional cache ID parts based provided by drupal_render_cid_parts().
        $cid_parts = array_merge($elements['#cache']['keys'], drupal_render_cid_parts($granularity));
        return implode(':', $cid_parts);
      }
      return FALSE;
    }
    
    /**
     * Function used by uasort to sort structured arrays by weight.
     */
    function element_sort($a, $b) {
      $a_weight = (is_array($a) && isset($a['#weight'])) ? $a['#weight'] : 0;
      $b_weight = (is_array($b) && isset($b['#weight'])) ? $b['#weight'] : 0;
      if ($a_weight == $b_weight) {
        return 0;
      }
      return ($a_weight < $b_weight) ? -1 : 1;
    }
    
    /**
     * Retrieve the default properties for the defined element type.
     */
    function element_info($type) {
      $cache = &drupal_static(__FUNCTION__);
    
      if (!isset($cache)) {
        $basic_defaults = element_basic_defaults();
        $cache = module_invoke_all('element_info');
        foreach ($cache as $element_type => $info) {
          $cache[$element_type] = array_merge_recursive($basic_defaults, $info);
          $cache[$element_type]['#type'] = $element_type;
        }
        // Allow modules to alter the element type defaults.
        drupal_alter('element_info', $cache);
      }
    
      return isset($cache[$type]) ? $cache[$type] : array();
    }
    
    /**
     * Retrieve the basic default properties that are common to all elements.
     */
    function element_basic_defaults() {
      return array(
        '#description' => '',
        '#title' => '',
        '#attributes' => array(),
        '#required' => FALSE,
        '#attached' => array(),
      );
    }
    
    /**
     * Function used by uasort to sort structured arrays by weight, without the property weight prefix.
     */
    function drupal_sort_weight($a, $b) {
      $a_weight = (is_array($a) && isset($a['weight'])) ? $a['weight'] : 0;
      $b_weight = (is_array($b) && isset($b['weight'])) ? $b['weight'] : 0;
      if ($a_weight == $b_weight) {
        return 0;
      }
      return ($a_weight < $b_weight) ? -1 : 1;
    }
    
    /**
     * Check if the key is a property.
     */
    function element_property($key) {
      return $key[0] == '#';
    }
    
    /**
     * Get properties of a structured array element. Properties begin with '#'.
     */
    function element_properties($element) {
      return array_filter(array_keys((array) $element), 'element_property');
    }
    
    /**
     * Check if the key is a child.
     */
    function element_child($key) {
      return !isset($key[0]) || $key[0] != '#';
    }
    
    /**
     * Return the children of an element, optionally sorted by weight.
     *
     * @param $elements
     *   The element to be sorted.
     * @param $sort
     *   Boolean to indicate whether the children should be sorted by weight.
     * @return
     *   The array keys of the element's children.
     */
    function element_children(&$elements, $sort = FALSE) {
      // Do not attempt to sort elements which have already been sorted.
      $sort = isset($elements['#sorted']) ? !$elements['#sorted'] : $sort;
    
      // Filter out properties from the element, leaving only children.
      $children = array();
      $sortable = FALSE;
      foreach ($elements as $key => $value) {
        if ($key[0] !== '#') {
          $children[$key] = $value;
          if (is_array($value) && isset($value['#weight'])) {
            $sortable = TRUE;
          }
        }
      }
      // Sort the children if necessary.
      if ($sort && $sortable) {
        uasort($children, 'element_sort');
        // Put the sorted children back into $elements in the correct order, to
        // preserve sorting if the same element is passed through
        // element_children() twice.
        foreach ($children as $key => $child) {
          unset($elements[$key]);
          $elements[$key] = $child;
        }
        $elements['#sorted'] = TRUE;
      }
    
      return array_keys($children);
    }
    
    /**
     * Provide theme registration for themes across .inc files.
     */
    function drupal_common_theme() {
      return array(
        // theme.inc
        'placeholder' => array(
          'arguments' => array('text' => NULL)
        ),
        'html' => array(
          'arguments' => array('page' => NULL),
          'template' => 'html',
        ),
        'page' => array(
          'arguments' => array('page' => NULL),
          'template' => 'page',
        ),
        'maintenance_page' => array(
          'arguments' => array('content' => NULL, 'show_messages' => TRUE),
          'template' => 'maintenance-page',
        ),
        'update_page' => array(
          'arguments' => array('content' => NULL, 'show_messages' => TRUE),
        ),
        'install_page' => array(
          'arguments' => array('content' => NULL),
        ),
        'task_list' => array(
          'arguments' => array('items' => NULL, 'active' => NULL),
        ),
        'status_messages' => array(
          'arguments' => array('display' => NULL),
        ),
        'links' => array(
          'arguments' => array('links' => NULL, 'attributes' => array('class' => array('links')), 'heading' => array()),
        ),
        'image' => array(
          'arguments' => array('path' => NULL, 'alt' => '', 'title' => '', 'attributes' => array(), 'getsize' => TRUE),
        ),
        'breadcrumb' => array(
          'arguments' => array('breadcrumb' => NULL),
        ),
        'help' => array(
          'arguments' => array(),
        ),
        'submenu' => array(
          'arguments' => array('links' => NULL),
        ),
        'table' => array(
          'arguments' => array('header' => NULL, 'rows' => NULL, 'attributes' => array(), 'caption' => NULL, 'colgroups' => array(), 'sticky' => TRUE),
        ),
        'table_select_header_cell' => array(
          'arguments' => array(),
        ),
        'tablesort_indicator' => array(
          'arguments' => array('style' => NULL),
        ),
        'mark' => array(
          'arguments' => array('type' => MARK_NEW),
        ),
        'item_list' => array(
          'arguments' => array('items' => array(), 'title' => NULL, 'type' => 'ul', 'attributes' => array()),
        ),
        'more_help_link' => array(
          'arguments' => array('url' => NULL),
        ),
        'feed_icon' => array(
          'arguments' => array('url' => NULL, 'title' => NULL),
        ),
        'more_link' => array(
          'arguments' => array('url' => NULL, 'title' => NULL)
        ),
        'blocks' => array(
          'arguments' => array('region' => NULL),
        ),
        'username' => array(
          'arguments' => array('object' => NULL),
        ),
        'progress_bar' => array(
          'arguments' => array('percent' => NULL, 'message' => NULL),
        ),
        'indentation' => array(
          'arguments' => array('size' => 1),
        ),
        // from pager.inc
        'pager' => array(
          'arguments' => array('tags' => array(), 'element' => 0, 'parameters' => array(), 'quantity' => 9),
        ),
        'pager_first' => array(
          'arguments' => array('text' => NULL, 'element' => 0, 'parameters' => array()),
        ),
        'pager_previous' => array(
          'arguments' => array('text' => NULL, 'element' => 0, 'interval' => 1, 'parameters' => array()),
        ),
        'pager_next' => array(
          'arguments' => array('text' => NULL, 'element' => 0, 'interval' => 1, 'parameters' => array()),
        ),
        'pager_last' => array(
          'arguments' => array('text' => NULL, 'element' => 0, 'parameters' => array()),
        ),
        'pager_link' => array(
          'arguments' => array('text' => NULL, 'page_new' => NULL, 'element' => NULL, 'parameters' => array(), 'attributes' => array()),
        ),
        // from locale.inc
        'locale_admin_manage_screen' => array(
          'arguments' => array('form' => NULL),
        ),
        // from menu.inc
        'menu_link' => array(
          'arguments' => array('element' => NULL),
        ),
        'menu_tree' => array(
          'arguments' => array('tree' => NULL),
        ),
        'menu_local_task' => array(
          'arguments' => array('link' => NULL, 'active' => FALSE),
        ),
        'menu_local_action' => array(
          'arguments' => array('link' => NULL),
        ),
        'menu_local_tasks' => array(
          'arguments' => array(),
        ),
        // from form.inc
        'select' => array(
          'arguments' => array('element' => NULL),
        ),
        'fieldset' => array(
          'arguments' => array('element' => NULL),
        ),
        'radio' => array(
          'arguments' => array('element' => NULL),
        ),
        'radios' => array(
          'arguments' => array('element' => NULL),
        ),
        'date' => array(
          'arguments' => array('element' => NULL),
        ),
        'checkbox' => array(
          'arguments' => array('element' => NULL),
        ),
        'checkboxes' => array(
          'arguments' => array('element' => NULL),
        ),
        'button' => array(
          'arguments' => array('element' => NULL),
        ),
        'image_button' => array(
          'arguments' => array('element' => NULL),
        ),
        'hidden' => array(
          'arguments' => array('element' => NULL),
        ),
        'textfield' => array(
          'arguments' => array('element' => NULL),
        ),
        'form' => array(
          'arguments' => array('element' => NULL),
        ),
        'textarea' => array(
          'arguments' => array('element' => NULL),
        ),
        'markup' => array(
          'arguments' => array('element' => NULL),
        ),
        'password' => array(
          'arguments' => array('element' => NULL),
        ),
        'file' => array(
          'arguments' => array('element' => NULL),
        ),
        'tableselect' => array(
          'arguments' => array('element' => NULL),
        ),
        'form_element' => array(
          'arguments' => array('element' => NULL),
        ),
        'text_format_wrapper' => array(
          'arguments' => array('element' => NULL),
        ),
        'vertical_tabs' => array(
          'arguments' => array('element' => NULL),
        ),
      );
    }
    
    /**
     * @ingroup schemaapi
     * @{
     */
    
    /**
     * Create all tables that a module defines in its hook_schema().
     *
     * Note: This function does not pass the module's schema through
     * hook_schema_alter(). The module's tables will be created exactly as the
     * module defines them.
     *
     * @param $module
     *   The module for which the tables will be created.
     * @return
     *   An array of arrays with the following key/value pairs:
     *    - success: a boolean indicating whether the query succeeded.
     *    - query: the SQL query(s) executed, passed through check_plain().
     */
    function drupal_install_schema($module) {
      $schema = drupal_get_schema_unprocessed($module);
      _drupal_schema_initialize($module, $schema);
    
      $ret = array();
      foreach ($schema as $name => $table) {
        db_create_table($ret, $name, $table);
      }
      return $ret;
    }
    
    /**
     * Remove all tables that a module defines in its hook_schema().
     *
     * Note: This function does not pass the module's schema through
     * hook_schema_alter(). The module's tables will be created exactly as the
     * module defines them.
     *
     * @param $module
     *   The module for which the tables will be removed.
     * @return
     *   An array of arrays with the following key/value pairs:
     *    - success: a boolean indicating whether the query succeeded.
     *    - query: the SQL query(s) executed, passed through check_plain().
     */
    function drupal_uninstall_schema($module) {
      $schema = drupal_get_schema_unprocessed($module);
      _drupal_schema_initialize($module, $schema);
    
      $ret = array();
      foreach ($schema as $table) {
        if (db_table_exists($table['name'])) {
          db_drop_table($ret, $table['name']);
        }
      }
      return $ret;
    }
    
    /**
     * Returns the unprocessed and unaltered version of a module's schema.
     *
     * Use this function only if you explicitly need the original
     * specification of a schema, as it was defined in a module's
     * hook_schema(). No additional default values will be set,
     * hook_schema_alter() is not invoked and these unprocessed
     * definitions won't be cached.
     *
     * This function can be used to retrieve a schema specification in
     * hook_schema(), so it allows you to derive your tables from existing
     * specifications.
     *
     * It is also used by drupal_install_schema() and
     * drupal_uninstall_schema() to ensure that a module's tables are
     * created exactly as specified without any changes introduced by a
     * module that implements hook_schema_alter().
     *
     * @param $module
     *   The module to which the table belongs.
     * @param $table
     *   The name of the table. If not given, the module's complete schema
     *   is returned.
     */
    function drupal_get_schema_unprocessed($module, $table = NULL) {
      // Load the .install file to get hook_schema.
      module_load_install($module);
      $schema = module_invoke($module, 'schema');
    
      if (!is_null($table) && isset($schema[$table])) {
        return $schema[$table];
      }
      else if (!empty($schema)) {
        return $schema;
      }
      return array();
    }
    
    /**
     * Fill in required default values for table definitions returned by hook_schema().
     *
     * @param $module
     *   The module for which hook_schema() was invoked.
     * @param $schema
     *   The schema definition array as it was returned by the module's
     *   hook_schema().
     */
    function _drupal_schema_initialize($module, &$schema) {
      // Set the name and module key for all tables.
      foreach ($schema as $name => $table) {
        if (empty($table['module'])) {
          $schema[$name]['module'] = $module;
        }
        if (!isset($table['name'])) {
          $schema[$name]['name'] = $name;
        }
      }
    }
    
    /**
     * Retrieve a list of fields from a table schema. The list is suitable for use in a SQL query.
     *
     * @param $table
     *   The name of the table from which to retrieve fields.
     * @param
     *   An optional prefix to to all fields.
     *
     * @return An array of fields.
     **/
    function drupal_schema_fields_sql($table, $prefix = NULL) {
      $schema = drupal_get_schema($table);
      $fields = array_keys($schema['fields']);
      if ($prefix) {
        $columns = array();
        foreach ($fields as $field) {
          $columns[] = "$prefix.$field";
        }
        return $columns;
      }
      else {
        return $fields;
      }
    }
    
    /**
     * Save a record to the database based upon the schema.
     *
     * Default values are filled in for missing items, and 'serial' (auto increment)
     * types are filled in with IDs.
     *
     * @param $table
     *   The name of the table; this must exist in schema API.
     * @param $object
     *   The object to write. This is a reference, as defaults according to
     *   the schema may be filled in on the object, as well as ID on the serial
     *   type(s). Both array an object types may be passed.
     * @param $primary_keys
     *   If this is an update, specify the primary keys' field names. It is the
     *   caller's responsibility to know if a record for this object already
     *   exists in the database. If there is only 1 key, you may pass a simple string.
     * @return
     *   Failure to write a record will return FALSE. Otherwise SAVED_NEW or
     *   SAVED_UPDATED is returned depending on the operation performed. The
     *   $object parameter contains values for any serial fields defined by
     *   the $table. For example, $object->nid will be populated after inserting
     *   a new node.
     */
    function drupal_write_record($table, &$object, $primary_keys = array()) {
      // Standardize $primary_keys to an array.
      if (is_string($primary_keys)) {
        $primary_keys = array($primary_keys);
      }
    
      $schema = drupal_get_schema($table);
      if (empty($schema)) {
        return FALSE;
      }
    
      // Convert to an object if needed.
      if (is_array($object)) {
        $object = (object) $object;
        $array = TRUE;
      }
      else {
        $array = FALSE;
      }
    
      $fields = array();
    
      // Go through our schema, build SQL, and when inserting, fill in defaults for
      // fields that are not set.
      foreach ($schema['fields'] as $field => $info) {
        // Special case -- skip serial types if we are updating.
        if ($info['type'] == 'serial' && !empty($primary_keys)) {
          continue;
        }
    
        // For inserts, populate defaults from schema if not already provided.
        if (!isset($object->$field) && empty($primary_keys) && isset($info['default'])) {
          $object->$field = $info['default'];
        }
    
        // Track serial field so we can helpfully populate them after the query.
        // NOTE: Each table should come with one serial field only.
        if ($info['type'] == 'serial') {
          $serial = $field;
        }
    
        // Build arrays for the fields and values in our query.
        if (isset($object->$field)) {
          if (empty($info['serialize'])) {
            $fields[$field] = $object->$field;
          }
          elseif (!empty($object->$field)) {
            $fields[$field] = serialize($object->$field);
          }
          else {
            $fields[$field] = '';
          }
        }
    
        // We don't need to care about type casting if value does not exist.
        if (!isset($fields[$field])) {
          continue;
        }
    
        // Special case -- skip null value if field allows null.
        if ($fields[$field] == NULL && $info['not null'] == FALSE) {
          continue;
        }
    
        // Type cast if field does not allow null. Required by DB API.
        if ($info['type'] == 'int' || $info['type'] == 'serial') {
          $fields[$field] = (int) $fields[$field];
        }
        elseif ($info['type'] == 'float') {
          $fields[$field] = (float) $fields[$field];
        }
        else {
          $fields[$field] = (string) $fields[$field];
        }
      }
    
      if (empty($fields)) {
        // No changes requested.
        // If we began with an array, convert back so we don't surprise the caller.
        if ($array) {
          $object = (array) $object;
        }
        return;
      }
    
      // Build the SQL.
      if (empty($primary_keys)) {
        $options = array('return' => Database::RETURN_INSERT_ID);
        if (isset($serial) && isset($fields[$serial])) {
          // If the serial column has been explicitly set with an ID, then we don't
          // require the database to return the last insert id.
          if ($fields[$serial]) {
            $options['return'] = Database::RETURN_AFFECTED;
          }
          // If a serial column does exist with no value (i.e. 0) then remove it as
          // the database will insert the correct value for us.
          else {
            unset($fields[$serial]);
          }
        }
        $query = db_insert($table, $options)->fields($fields);
        $return = SAVED_NEW;
      }
      else {
        $query = db_update($table)->fields($fields);
        foreach ($primary_keys as $key) {
          $query->condition($key, $object->$key);
        }
        $return = SAVED_UPDATED;
      }
    
      // Execute the SQL.
      if ($last_insert_id = $query->execute()) {
        if (isset($serial)) {
          // If the database was not told to return the last insert id, it will be
          // because we already know it.
          if (isset($options) && $options['return'] != Database::RETURN_INSERT_ID) {
            $object->$serial = $fields[$serial];
          }
          else {
            $object->$serial = $last_insert_id;
          }
        }
      }
      // If we have a single-field primary key but got no insert ID, the
      // query failed.
      elseif (count($primary_keys) == 1) {
        $return = FALSE;
      }
    
      // If we began with an array, convert back so we don't surprise the caller.
      if ($array) {
        $object = (array) $object;
      }
    
      return $return;
    }
    
    /**
     * @} End of "ingroup schemaapi".
     */
    
    /**
     * Parse Drupal info file format.
     *
     * Files should use an ini-like format to specify values.
     * White-space generally doesn't matter, except inside values.
     * e.g.
     *
     * @verbatim
     *   key = value
     *   key = "value"
     *   key = 'value'
     *   key = "multi-line
     *
     *   value"
     *   key = 'multi-line
     *
     *   value'
     *   key
     *   =
     *   'value'
     * @endverbatim
     *
     * Arrays are created using a GET-like syntax:
     *
     * @verbatim
     *   key[] = "numeric array"
     *   key[index] = "associative array"
     *   key[index][] = "nested numeric array"
     *   key[index][index] = "nested associative array"
     * @endverbatim
     *
     * PHP constants are substituted in, but only when used as the entire value:
     *
     * Comments should start with a semi-colon at the beginning of a line.
     *
     * This function is NOT for placing arbitrary module-specific settings. Use
     * variable_get() and variable_set() for that.
     *
     * Information stored in the module.info file:
     * - name: The real name of the module for display purposes.
     * - description: A brief description of the module.
     * - dependencies: An array of shortnames of other modules this module requires.
     * - package: The name of the package of modules this module belongs to.
     *
     * Example of .info file:
     * @verbatim
     *   name = Forum
     *   description = Enables threaded discussions about general topics.
     *   dependencies[] = taxonomy
     *   dependencies[] = comment
     *   package = Core
     *   version = VERSION
     * @endverbatim
     *
     * @param $filename
     *   The file we are parsing. Accepts file with relative or absolute path.
     * @return
     *   The info array.
     */
    function drupal_parse_info_file($filename) {
      $info = array();
    
      if (!file_exists($filename)) {
        return $info;
      }
    
      $data = file_get_contents($filename);
      if (preg_match_all('
        @^\s*                           # Start at the beginning of a line, ignoring leading whitespace
        ((?:
          [^=;\[\]]|                    # Key names cannot contain equal signs, semi-colons or square brackets,
          \[[^\[\]]*\]                  # unless they are balanced and not nested
        )+?)
        \s*=\s*                         # Key/value pairs are separated by equal signs (ignoring white-space)
        (?:
          ("(?:[^"]|(?<=\\\\)")*")|     # Double-quoted string, which may contain slash-escaped quotes/slashes
          (\'(?:[^\']|(?<=\\\\)\')*\')| # Single-quoted string, which may contain slash-escaped quotes/slashes
          ([^\r\n]*?)                   # Non-quoted string
        )\s*$                           # Stop at the next end of a line, ignoring trailing whitespace
        @msx', $data, $matches, PREG_SET_ORDER)) {
        foreach ($matches as $match) {
          // Fetch the key and value string
          $i = 0;
          foreach (array('key', 'value1', 'value2', 'value3') as $var) {
            $$var = isset($match[++$i]) ? $match[$i] : '';
          }
          $value = stripslashes(substr($value1, 1, -1)) . stripslashes(substr($value2, 1, -1)) . $value3;
    
          // Parse array syntax
          $keys = preg_split('/\]?\[/', rtrim($key, ']'));
          $last = array_pop($keys);
          $parent = &$info;
    
          // Create nested arrays
          foreach ($keys as $key) {
            if ($key == '') {
              $key = count($parent);
            }
            if (!isset($parent[$key]) || !is_array($parent[$key])) {
              $parent[$key] = array();
            }
            $parent = &$parent[$key];
          }
    
          // Handle PHP constants
          if (defined($value)) {
            $value = constant($value);
          }
    
          // Insert actual value
          if ($last == '') {
            $last = count($parent);
          }
          $parent[$last] = $value;
        }
      }
    
      return $info;
    }
    
    /**
     * Severity levels, as defined in RFC 3164: http://www.ietf.org/rfc/rfc3164.txt.
     *
     * @return
     *   Array of the possible severity levels for log messages.
     *
     * @see watchdog()
     */
    function watchdog_severity_levels() {
      return array(
        WATCHDOG_EMERG    => t('emergency'),
        WATCHDOG_ALERT    => t('alert'),
        WATCHDOG_CRITICAL => t('critical'),
        WATCHDOG_ERROR    => t('error'),
        WATCHDOG_WARNING  => t('warning'),
        WATCHDOG_NOTICE   => t('notice'),
        WATCHDOG_INFO     => t('info'),
        WATCHDOG_DEBUG    => t('debug'),
      );
    }
    
    
    /**
     * Explode a string of given tags into an array.
     */
    function drupal_explode_tags($tags) {
      // This regexp allows the following types of user input:
      // this, "somecompany, llc", "and ""this"" w,o.rks", foo bar
      $regexp = '%(?:^|,\ *)("(?>[^"]*)(?>""[^"]* )*"|(?: [^",]*))%x';
      preg_match_all($regexp, $tags, $matches);
      $typed_tags = array_unique($matches[1]);
    
      $tags = array();
      foreach ($typed_tags as $tag) {
        // If a user has escaped a term (to demonstrate that it is a group,
        // or includes a comma or quote character), we remove the escape
        // formatting so to save the term into the database as the user intends.
        $tag = trim(str_replace('""', '"', preg_replace('/^"(.*)"$/', '\1', $tag)));
        if ($tag != "") {
          $tags[] = $tag;
        }
      }
    
      return $tags;
    }
    
    /**
     * Implode an array of tags into a string.
     */
    function drupal_implode_tags($tags) {
      $encoded_tags = array();
      foreach ($tags as $tag) {
        // Commas and quotes in tag names are special cases, so encode them.
        if (strpos($tag, ',') !== FALSE || strpos($tag, '"') !== FALSE) {
          $tag = '"' . str_replace('"', '""', $tag) . '"';
        }
    
        $encoded_tags[] = $tag;
      }
      return implode(', ', $encoded_tags);
    }
    
    /**
     * Flush all cached data on the site.
     *
     * Empties cache tables, rebuilds the menu cache and theme registries, and
     * invokes a hook so that other modules' cache data can be cleared as well.
     */
    function drupal_flush_all_caches() {
      // Change query-strings on css/js files to enforce reload for all users.
      _drupal_flush_css_js();
    
      registry_rebuild();
      drupal_clear_css_cache();
      drupal_clear_js_cache();
    
      // If invoked from update.php, we must not update the theme information in the
      // database, or this will result in all themes being disabled.
      if (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'update') {
        _system_get_theme_data();
      }
      else {
        system_get_theme_data();
      }
    
      drupal_theme_rebuild();
      menu_rebuild();
      node_types_rebuild();
      // Don't clear cache_form - in-progress form submissions may break.
      // Ordered so clearing the page cache will always be the last action.
      $core = array('cache', 'cache_filter', 'cache_registry', 'cache_page');
      $cache_tables = array_merge(module_invoke_all('flush_caches'), $core);
      foreach ($cache_tables as $table) {
        cache_clear_all('*', $table, TRUE);
      }
    }
    
    /**
     * Helper function to change query-strings on css/js files.
     *
     * Changes the character added to all css/js files as dummy query-string,
     * so that all browsers are forced to reload fresh files. We keep
     * 20 characters history (FIFO) to avoid repeats, but only the first
     * (newest) character is actually used on urls, to keep them short.
     * This is also called from update.php.
     */
    function _drupal_flush_css_js() {
      $string_history = variable_get('css_js_query_string', '00000000000000000000');
      $new_character = $string_history[0];
      // Not including 'q' to allow certain JavaScripts to re-use query string.
      $characters = 'abcdefghijklmnoprstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
      while (strpos($string_history, $new_character) !== FALSE) {
        $new_character = $characters[mt_rand(0, strlen($characters) - 1)];
      }
      variable_set('css_js_query_string', $new_character . substr($string_history, 0, 19));
    }
    
    /**
     * Debug function used for outputting debug information.
     *
     * The debug information is passed on to trigger_error() after being converted
     * to a string using _drupal_debug_message().
     *
     * @param $data
     *   Data to be output.
     * @param $label
     *   Label to prefix the data.
     * @param $print_r
     *   Flag to switch between print_r() and var_export() for data conversion to
     *   string. Set $print_r to TRUE when dealing with a recursive data structure
     *   as var_export() will generate an error.
     */
    function debug($data, $label = NULL, $print_r = FALSE) {
      // Print $data contents to string.
      $string = $print_r ? print_r($data, TRUE) : var_export($data, TRUE);
      trigger_error(trim($label ? "$label: $string" : $string));
    }
    
    /**
     * Parse a dependency for comparison by drupal_check_incompatibility().
     *
     * @param $dependency
     *   A dependency string, for example 'foo (>=7.x-4.5-beta5, 3.x)'.
     * @return
     *   An associative array with three keys:
     *   - 'name' includes the name of the thing to depend on (e.g. 'foo').
     *   - 'original_version' contains the original version string (which can be
     *     used in the UI for reporting incompatibilities).
     *   - 'versions' is a list of associative arrays, each containing the keys
     *     'op' and 'version'. 'op' can be one of: '=', '==', '!=', '<>', '<',
     *     '<=', '>', or '>='. 'version' is one piece like '4.5-beta3'.
     *   Callers should pass this structure to drupal_check_incompatibility().
     *
     * @see drupal_check_incompatibility()
     */
    function drupal_parse_dependency($dependency) {
      // We use named subpatterns and support every op that version_compare
      // supports. Also, op is optional and defaults to equals.
      $p_op = '(?P<operation>!=|==|=|<|<=|>|>=|<>)?';
      // Core version is always optional: 7.x-2.x and 2.x is treated the same.
      $p_core = '(?:' . preg_quote(DRUPAL_CORE_COMPATIBILITY) . '-)?';
      $p_major = '(?P<major>\d+)';
      // By setting the minor version to x, branches can be matched.
      $p_minor = '(?P<minor>(?:\d+|x)(?:-[A-Za-z]+\d+)?)';
      $value = array();
      $parts = explode('(', $dependency, 2);
      $value['name'] = trim($parts[0]);
      if (isset($parts[1])) {
        $value['original_version'] = ' (' . $parts[1];
        foreach (explode(',', $parts[1]) as $version) {
          if (preg_match("/^\s*$p_op\s*$p_core$p_major\.$p_minor/", $version, $matches)) {
            $op = !empty($matches['operation']) ? $matches['operation'] : '=';
            if ($matches['minor'] == 'x') {
              // Drupal considers "2.x" to mean any version that begins with
              // "2" (e.g. 2.0, 2.9 are all "2.x"). PHP's version_compare(),
              // on the other hand, treats "x" as a string; so to
              // version_compare(), "2.x" is considered less than 2.0. This
              // means that >=2.x and <2.x are handled by version_compare()
              // as we need, but > and <= are not.
              if ($op == '>' || $op == '<=') {
                $matches['major']++;
              }
              // Equivalence can be checked by adding two restrictions.
              if ($op == '=' || $op == '==') {
                $value['versions'][] = array('op' => '<', 'version' => ($matches['major'] + 1) . '.x');
                $op = '>=';
              }
            }
            $value['versions'][] = array('op' => $op, 'version' => $matches['major'] . '.' . $matches['minor']);
          }
        }
      }
      return $value;
    }
    
    /**
     * Check whether a version is compatible with a given dependency.
     *
     * @param $v
     *   The parsed dependency structure from drupal_parse_dependency().
     * @param $current_version
     *   The version to check against (like 4.2).
     * @return
     *   NULL if compatible, otherwise the original dependency version string that
     *   caused the incompatiblity.
     *
     * @see drupal_parse_dependency()
     */
    function drupal_check_incompatibility($v, $current_version) {
      if (!empty($v['versions'])) {
        foreach ($v['versions'] as $required_version) {
          if ((isset($required_version['op']) && !version_compare($current_version, $required_version['version'], $required_version['op']))) {
            return $v['original_version'];
          }
        }
      }
    }
    
    /**
     * Get the entity info array of an entity type.
     *
     * @see hook_entity_info()
     * @see hook_entity_info_alter()
     *
     * @param $entity_type
     *   The entity type, e.g. node, for which the info shall be returned, or NULL
     *   to return an array with info about all types.
     */
    function entity_get_info($entity_type = NULL) {
      // We statically cache the information returned by hook_entity_info().
      $entity_info = &drupal_static(__FUNCTION__, array());
    
      if (empty($entity_info)) {
        if ($cache = cache_get('entity_info')) {
          $entity_info = $cache->data;
        }
        else {
          $entity_info = module_invoke_all('entity_info');
          // Merge in default values.
          foreach ($entity_info as $name => $data) {
            $entity_info[$name] += array(
              'fieldable' => FALSE,
              'controller class' => 'DrupalDefaultEntityController',
              'static cache' => TRUE,
              'load hook' => $name . '_load',
            );
          }
          // Let other modules alter the entity info.
          drupal_alter('entity_info', $entity_info);
          cache_set('entity_info', $entity_info);
        }
      }
    
      return empty($entity_type) ? $entity_info : $entity_info[$entity_type];
    }
    
    /**
     * Load entities from the database.
     *
     * This function should be used whenever you need to load more than one entity
     * from the database. The entities are loaded into memory and will not require
     * database access if loaded again during the same page request.
     *
     * The actual loading is done through a class that has to implement the
     * DrupalEntityController interface. By default, DrupalDefaultEntityController
     * is used. Entity types can specify that a different class should be used by
     * setting the 'controller class' key in hook_entity_info(). These classes can
     * either implement the DrupalEntityController interface, or, most commonly,
     * extend the DrupalDefaultEntityController class. See node_entity_info() and
     * the NodeController in node.module as an example.
     *
     * @see hook_entity_info()
     * @see DrupalEntityController
     * @see DrupalDefaultEntityController
     *
     * @param $entity_type
     *   The entity type to load, e.g. node or user.
     * @param $ids
     *   An array of entity IDs, or FALSE to load all entities.
     * @param $conditions
     *   An array of conditions in the form 'field' => $value.
     * @param $reset
     *   Whether to reset the internal cache for the requested entity type.
     *
     * @return
     *   An array of entity objects indexed by their ids.
     */
    function entity_load($entity_type, $ids = array(), $conditions = array(), $reset = FALSE) {
      if ($reset) {
        entity_get_controller($entity_type)->resetCache();
      }
      return entity_get_controller($entity_type)->load($ids, $conditions);
    }
    
    /**
     * Get the entity controller class for an entity type.
     */
    function entity_get_controller($entity_type) {
      $controllers = &drupal_static(__FUNCTION__, array());
      if (!isset($controllers[$entity_type])) {
        $type_info = entity_get_info($entity_type);
        $class = $type_info['controller class'];
        $controllers[$entity_type] = new $class($entity_type);
      }
      return $controllers[$entity_type];
    }
    
    /**
     * Performs one or more XML-RPC request(s).
     *
     * @param $url
     *   An absolute URL of the XML-RPC endpoint.
     *     Example:
     *     http://www.example.com/xmlrpc.php
     * @param ...
     *   For one request:
     *     The method name followed by a variable number of arguments to the method.
     *   For multiple requests (system.multicall):
     *     An array of call arrays. Each call array follows the pattern of the single
     *     request: method name followed by the arguments to the method.
     * @return
     *   For one request:
     *     Either the return value of the method on success, or FALSE.
     *     If FALSE is returned, see xmlrpc_errno() and xmlrpc_error_msg().
     *   For multiple requests:
     *     An array of results. Each result will either be the result
     *     returned by the method called, or an xmlrpc_error object if the call
     *     failed. See xmlrpc_error().
     */
    function xmlrpc($url) {
      require_once DRUPAL_ROOT . '/includes/xmlrpc.inc';
      $args = func_get_args();
      return call_user_func_array('_xmlrpc', $args);
    }