common.inc 144 KB
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<?php
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// $Id$
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/**
 * @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.
 */

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/**
 * 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);

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/**
 * 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);

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/**
 * Set content for a specified region.
 *
 * @param $region
 *   Page region the content is assigned to.
 * @param $data
 *   Content to be set.
 */
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function drupal_set_content($region = NULL, $data = NULL) {
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  static $content = array();

  if (!is_null($region) && !is_null($data)) {
    $content[$region][] = $data;
  }
  return $content;
}

/**
 * Get assigned content.
 *
 * @param $region
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 *   A specified region to fetch content for. If NULL, all regions will be
 *   returned.
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 * @param $delimiter
 *   Content to be inserted between exploded array elements.
 */
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function drupal_get_content($region = NULL, $delimiter = ' ') {
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  $content = drupal_set_content();
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  if (isset($region)) {
    if (isset($content[$region]) && is_array($content[$region])) {
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      return implode($delimiter, $content[$region]);
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    }
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  }
  else {
    foreach (array_keys($content) as $region) {
      if (is_array($content[$region])) {
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        $content[$region] = implode($delimiter, $content[$region]);
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      }
    }
    return $content;
  }
}

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/**
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 * Set the breadcrumb trail for the current page.
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 *
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 * @param $breadcrumb
 *   Array of links, starting with "home" and proceeding up to but not including
 *   the current page.
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 */
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function drupal_set_breadcrumb($breadcrumb = NULL) {
  static $stored_breadcrumb;

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  if (!is_null($breadcrumb)) {
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    $stored_breadcrumb = $breadcrumb;
  }
  return $stored_breadcrumb;
}

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/**
 * Get the breadcrumb trail for the current page.
 */
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function drupal_get_breadcrumb() {
  $breadcrumb = drupal_set_breadcrumb();

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  if (is_null($breadcrumb)) {
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    $breadcrumb = menu_get_active_breadcrumb();
  }

  return $breadcrumb;
}

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/**
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 * Return a string containing RDF namespaces for the <html> tag of an XHTML
 * page.
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 */
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);
}

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/**
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 * Add output to the head tag of the HTML page.
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 *
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 * This function can be called as long the headers aren't sent.
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 */
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function drupal_add_html_head($data = NULL) {
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  static $stored_head = '';
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  if (!is_null($data)) {
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    $stored_head .= $data . "\n";
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  }
  return $stored_head;
}

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/**
 * Retrieve output to be displayed in the head tag of the HTML page.
 */
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function drupal_get_html_head() {
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  $output = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />\n";
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  return $output . drupal_add_html_head();
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}

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/**
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 * Reset the static variable which holds the aliases mapped for this request.
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 */
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function drupal_clear_path_cache() {
  drupal_lookup_path('wipe');
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}
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/**
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 * Add a feed URL for the current page.
 *
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 * This function can be called as long the HTML header hasn't been sent.
 *
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 * @param $url
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 *   A url for the feed.
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 * @param $title
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 *   The title of the feed.
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 */
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function drupal_add_feed($url = NULL, $title = '') {
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  static $stored_feed_links = array();

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  if (!is_null($url) && !isset($stored_feed_links[$url])) {
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    $stored_feed_links[$url] = theme('feed_icon', $url, $title);
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    drupal_add_link(array('rel' => 'alternate',
                          'type' => 'application/rss+xml',
                          'title' => $title,
                          'href' => $url));
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  }
  return $stored_feed_links;
}

/**
 * Get the feed URLs for the current page.
 *
 * @param $delimiter
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 *   A delimiter to split feeds by.
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 */
function drupal_get_feeds($delimiter = "\n") {
  $feeds = drupal_add_feed();
  return implode($feeds, $delimiter);
}

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/**
 * @name HTTP handling
 * @{
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 * Functions to properly handle HTTP responses.
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 */

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/**
 * Parse an array into a valid urlencoded query string.
 *
 * @param $query
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 *   The array to be processed e.g. $_GET.
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 * @param $exclude
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 *   The array filled with keys to be excluded. Use parent[child] to exclude
 *   nested items.
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 * @param $parent
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 *   Should not be passed, only used in recursive calls.
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 * @return
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 *   An urlencoded string which can be appended to/as the URL query string.
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 */
function drupal_query_string_encode($query, $exclude = array(), $parent = '') {
  $params = array();

  foreach ($query as $key => $value) {
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    $key = drupal_urlencode($key);
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    if ($parent) {
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      $key = $parent . '[' . $key . ']';
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    }

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    if (in_array($key, $exclude)) {
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      continue;
    }

    if (is_array($value)) {
      $params[] = drupal_query_string_encode($value, $exclude, $key);
    }
    else {
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      $params[] = $key . '=' . drupal_urlencode($value);
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    }
  }

  return implode('&', $params);
}

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/**
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 * Prepare a destination query string for use in combination with drupal_goto().
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 *
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 * 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.
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 *
 * @see drupal_goto()
 */
function drupal_get_destination() {
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  if (isset($_REQUEST['destination'])) {
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    return 'destination=' . urlencode($_REQUEST['destination']);
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  }
  else {
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    // Use $_GET here to retrieve the original path in source form.
    $path = isset($_GET['q']) ? $_GET['q'] : '';
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    $query = drupal_query_string_encode($_GET, array('q'));
    if ($query != '') {
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      $path .= '?' . $query;
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    }
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    return 'destination=' . urlencode($path);
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  }
}

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/**
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 * Send the user to a different Drupal page.
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 *
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 * This issues an on-site HTTP redirect. The function makes sure the redirected
 * URL is formatted correctly.
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 *
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 * Usually the redirected URL is constructed from this function's input
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 * parameters. However you may override that behavior by setting a
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 * destination in either the $_REQUEST-array (i.e. by using
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 * the query string of an URI) This is used to direct the user back to
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 * the proper page after completing a form. For example, after editing
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 * a post on the 'admin/content/node'-page or after having logged on using the
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 * 'user login'-block in a sidebar. The function drupal_get_destination()
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 * can be used to help set the destination URL.
 *
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 * Drupal will ensure that messages set by drupal_set_message() and other
 * session data are written to the database before the user is redirected.
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 *
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 * This function ends the request; use it instead of a return in your menu callback.
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 *
 * @param $path
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 *   A Drupal path or a full URL.
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 * @param $query
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 *   A query string component, if any.
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 * @param $fragment
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 *   A destination fragment identifier (named anchor).
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 * @param $http_response_code
 *   Valid values for an actual "goto" as per RFC 2616 section 10.3 are:
 *   - 301 Moved Permanently (the recommended value for most redirects)
 *   - 302 Found (default in Drupal and PHP, sometimes used for spamming search
 *         engines)
 *   - 303 See Other
 *   - 304 Not Modified
 *   - 305 Use Proxy
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 *   - 307 Temporary Redirect (alternative to "503 Site Down for Maintenance")
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 *   Note: Other values are defined by RFC 2616, but are rarely used and poorly
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 *   supported.
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 * @see drupal_get_destination()
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 */
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function drupal_goto($path = '', $query = NULL, $fragment = NULL, $http_response_code = 302) {
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  if (isset($_REQUEST['destination'])) {
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    extract(parse_url(urldecode($_REQUEST['destination'])));
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  }

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  $url = url($path, array('query' => $query, 'fragment' => $fragment, 'absolute' => TRUE));
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  // Allow modules to react to the end of the page request before redirecting.
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  // We do not want this while running update.php.
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  if (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update') {
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    module_invoke_all('exit', $url);
  }
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  if (drupal_session_is_started()) {
    // Even though session_write_close() is registered as a shutdown function,
    // we need all session data written to the database before redirecting.
    session_write_close();
  }
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  header('Location: ' . $url, TRUE, $http_response_code);
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  // The "Location" header sends a redirect status code to the HTTP daemon. In
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  // some cases this can be wrong, so we make sure none of the code below the
  // drupal_goto() call gets executed upon redirection.
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  exit();
}

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/**
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 * Generates a site offline message.
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 */
function drupal_site_offline() {
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  drupal_maintenance_theme();
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  drupal_set_header('503 Service unavailable');
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  drupal_set_title(t('Site offline'));
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  print theme('maintenance_page', filter_xss_admin(variable_get('site_offline_message',
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    t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => variable_get('site_name', 'Drupal'))))));
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}

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/**
 * Generates a 404 error if the request can not be handled.
 */
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function drupal_not_found() {
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  drupal_set_header('404 Not Found');
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  watchdog('page not found', check_plain($_GET['q']), NULL, WATCHDOG_WARNING);
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  // Keep old path for reference.
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  if (!isset($_REQUEST['destination'])) {
    $_REQUEST['destination'] = $_GET['q'];
  }

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  $path = drupal_get_normal_path(variable_get('site_404', ''));
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  if ($path && $path != $_GET['q']) {
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    // Custom 404 handler. Set the active item in case there are tabs to
    // display, or other dependencies on the path.
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    menu_set_active_item($path);
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    $return = menu_execute_active_handler($path);
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  }
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  if (empty($return) || $return == MENU_NOT_FOUND || $return == MENU_ACCESS_DENIED) {
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    // Standard 404 handler.
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    drupal_set_title(t('Page not found'));
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    $return = t('The requested page could not be found.');
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  }
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  $page = drupal_get_page($return);
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  // To conserve CPU and bandwidth, omit the blocks.
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  $page['#show_blocks'] = FALSE;

  print drupal_render_page($page);
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}
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/**
 * Generates a 403 error if the request is not allowed.
 */
function drupal_access_denied() {
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  drupal_set_header('403 Forbidden');
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  watchdog('access denied', check_plain($_GET['q']), NULL, WATCHDOG_WARNING);
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  // Keep old path for reference.
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  if (!isset($_REQUEST['destination'])) {
    $_REQUEST['destination'] = $_GET['q'];
  }

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  $path = drupal_get_normal_path(variable_get('site_403', ''));
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  if ($path && $path != $_GET['q']) {
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    // Custom 403 handler. Set the active item in case there are tabs to
    // display or other dependencies on the path.
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    menu_set_active_item($path);
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    $return = menu_execute_active_handler($path);
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  }
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  if (empty($return) || $return == MENU_NOT_FOUND || $return == MENU_ACCESS_DENIED) {
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    // Standard 403 handler.
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    drupal_set_title(t('Access denied'));
    $return = t('You are not authorized to access this page.');
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  }
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  print drupal_render_page($return);
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}

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/**
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 * Perform an HTTP request.
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 *
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 * This is a flexible and powerful HTTP client implementation. Correctly
 * handles GET, POST, PUT or any other HTTP requests. Handles redirects.
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 *
 * @param $url
 *   A string containing a fully qualified URI.
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 * @param $options
 *   (optional) An array which can have one or more of following keys:
 *   - headers
 *       An array containing request headers to send as name/value pairs.
 *   - method
 *       A string containing the request method. Defaults to 'GET'.
 *   - data
 *       A string containing the request body. Defaults to NULL.
 *   - max_redirects
 *       An integer representing how many times a redirect may be followed.
 *       Defaults to 3.
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 * @return
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 *   An object which can have one or more of the following parameters:
 *   - request
 *       A string containing the request body that was sent.
 *   - code
 *       An integer containing the response status code, or the error code if
 *       an error occurred.
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 *   - protocol
 *      The response protocol (e.g. HTTP/1.1 or HTTP/1.0).
 *   - status_message
 *      The status message from the response, if a response was received.
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 *   - redirect_code
 *       If redirected, an integer containing the initial response status code.
 *   - redirect_url
 *       If redirected, a string containing the redirection location.
 *   - error
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 *       If an error occurred, the error message. Otherwise not set.
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 *   - headers
 *       An array containing the response headers as name/value pairs.
 *   - data
 *       A string containing the response body that was received.
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 */
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function drupal_http_request($url, array $options = array()) {
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  global $db_prefix;
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  $result = new stdClass();
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  // Parse the URL and make sure we can handle the schema.
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  $uri = @parse_url($url);
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  if ($uri == FALSE) {
    $result->error = 'unable to parse URL';
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    return $result;
  }

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  if (!isset($uri['scheme'])) {
    $result->error = 'missing schema';
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    return $result;
  }

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  switch ($uri['scheme']) {
    case 'http':
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      $port = isset($uri['port']) ? $uri['port'] : 80;
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      $host = $uri['host'] . ($port != 80 ? ':' . $port : '');
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      $fp = @fsockopen($uri['host'], $port, $errno, $errstr, 15);
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      break;
    case 'https':
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      // Note: Only works when PHP is compiled with OpenSSL support.
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      $port = isset($uri['port']) ? $uri['port'] : 443;
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      $host = $uri['host'] . ($port != 443 ? ':' . $port : '');
      $fp = @fsockopen('ssl://' . $uri['host'], $port, $errno, $errstr, 20);
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      break;
    default:
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      $result->error = 'invalid schema ' . $uri['scheme'];
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      return $result;
  }

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  // Make sure the socket opened properly.
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  if (!$fp) {
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    // When a network error occurs, we use a negative number so it does not
    // clash with the HTTP status codes.
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    $result->code = -$errno;
    $result->error = trim($errstr);
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    // 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);

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    return $result;
  }

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  // Construct the path to act on.
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  $path = isset($uri['path']) ? $uri['path'] : '/';
  if (isset($uri['query'])) {
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    $path .= '?' . $uri['query'];
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  }

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  // Merge the default options.
  $options += array(
    'headers' => array(),
    'method' => 'GET',
    'data' => NULL,
    'max_redirects' => 3,
  );

  // Merge the default headers.
  $options['headers'] += array(
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    // RFC 2616: "non-standard ports MUST, default ports MAY be included".
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    // We don't add the port to prevent from breaking rewrite rules checking the
    // host that do not take into account the port number.
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    'Host' => $host,
    'User-Agent' => 'Drupal (+http://drupal.org/)',
    'Content-Length' => strlen($options['data']),
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  );

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  // If the server url has a user then attempt to use basic authentication
  if (isset($uri['user'])) {
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    $options['headers']['Authorization'] = 'Basic ' . base64_encode($uri['user'] . (!empty($uri['pass']) ? ":" . $uri['pass'] : ''));
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  }

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  // 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.
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  if (preg_match("/simpletest\d+/", $db_prefix, $matches)) {
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    $options['headers']['User-Agent'] = $matches[0];
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  }

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  foreach ($options['headers'] as $name => $value) {
    $options['headers'][$name] = $name . ': ' . trim($value);
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  }

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  $request = $options['method'] . ' ' . $path . " HTTP/1.0\r\n";
  $request .= implode("\r\n", $options['headers']);
  $request .= "\r\n\r\n" . $options['data'];
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  $result->request = $request;

  fwrite($fp, $request);

  // Fetch response.
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  $response = '';
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  while (!feof($fp) && $chunk = fread($fp, 1024)) {
    $response .= $chunk;
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  }
  fclose($fp);

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  // 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/", $response);
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  // Parse the response status line.
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  list($protocol, $code, $status_message) = explode(' ', trim(array_shift($response)), 3);
  $result->protocol = $protocol;
  $result->status_message = $status_message;

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  $result->headers = array();

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  // Parse the response headers.
  while ($line = trim(array_shift($response))) {
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    list($header, $value) = explode(':', $line, 2);
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    if (isset($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.
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      $result->headers[$header] .= ',' . trim($value);
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    }
    else {
      $result->headers[$header] = trim($value);
    }
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  }

  $responses = array(
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    100 => 'Continue',
    101 => 'Switching Protocols',
    200 => 'OK',
    201 => 'Created',
    202 => 'Accepted',
    203 => 'Non-Authoritative Information',
    204 => 'No Content',
    205 => 'Reset Content',
    206 => 'Partial Content',
    300 => 'Multiple Choices',
    301 => 'Moved Permanently',
    302 => 'Found',
    303 => 'See Other',
    304 => 'Not Modified',
    305 => 'Use Proxy',
    307 => 'Temporary Redirect',
    400 => 'Bad Request',
    401 => 'Unauthorized',
    402 => 'Payment Required',
    403 => 'Forbidden',
    404 => 'Not Found',
    405 => 'Method Not Allowed',
    406 => 'Not Acceptable',
    407 => 'Proxy Authentication Required',
    408 => 'Request Time-out',
    409 => 'Conflict',
    410 => 'Gone',
    411 => 'Length Required',
    412 => 'Precondition Failed',
    413 => 'Request Entity Too Large',
    414 => 'Request-URI Too Large',
    415 => 'Unsupported Media Type',
    416 => 'Requested range not satisfiable',
    417 => 'Expectation Failed',
    500 => 'Internal Server Error',
    501 => 'Not Implemented',
    502 => 'Bad Gateway',
    503 => 'Service Unavailable',
    504 => 'Gateway Time-out',
    505 => 'HTTP Version not supported',
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  );
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  // RFC 2616 states that all unknown HTTP codes must be treated the same as the
  // base code in their class.
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  if (!isset($responses[$code])) {
    $code = floor($code / 100) * 100;
  }
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  $result->code = $code;
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  switch ($code) {
    case 200: // OK
    case 304: // Not modified
      break;
    case 301: // Moved permanently
    case 302: // Moved temporarily
    case 307: // Moved temporarily
      $location = $result->headers['Location'];
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      if ($options['max_redirects']) {
        // Redirect to the new location.
        $options['max_redirects']--;
        $result = drupal_http_request($location, $options);
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        $result->redirect_code = $code;
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      }
      $result->redirect_url = $location;
      break;
    default:
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      $result->error = $status_message;
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  }

  return $result;
}
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/**
 * @} End of "HTTP handling".
 */
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/**
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 * Custom PHP error handler.
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 *
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 * @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'
    );
    $backtrace = debug_backtrace();
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    $caller = _drupal_get_last_caller(debug_backtrace());

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    // We treat recoverable errors as fatal.
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    _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);
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  }
}

/**
 * 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 $exception
 *   The exception object that was thrown.
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 */
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function _drupal_exception_handler($exception) {
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  // 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) {
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  $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.
    $db_functions = array('db_query', 'pager_query', 'db_query_range', 'db_query_temporary', 'update_sql');
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    while (!empty($backtrace[1]) && ($caller = $backtrace[1]) &&
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         ((isset($caller['class']) && (strpos($caller['class'], 'Query') !== FALSE || strpos($caller['class'], 'Database') !== FALSE)) ||
         in_array($caller['function'], $db_functions))) {
      // We remove that call.
      array_shift($backtrace);
    }
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  }
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  $caller = _drupal_get_last_caller($backtrace);
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  return array(
    '%type' => get_class($exception),
    '%message' => $exception->getMessage(),
    '%function' => $caller['function'],
    '%file' => $caller['file'],
    '%line' => $caller['line'],
  );
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}
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/**
 * Log a PHP error or exception, display an error page in fatal cases.
 *
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 * @param $error
 *   An array with the following keys: %type, %message, %function, %file, %line.
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 * @param $fatal
 *   TRUE if the error is fatal.
 */
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function _drupal_log_error($error, $fatal = FALSE) {
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  // Initialize a maintenance theme early if the boostrap was not complete.
  // Do it early because drupal_set_message() triggers an init_theme().
  if ($fatal && (drupal_get_bootstrap_phase() != DRUPAL_BOOTSTRAP_FULL)) {
    unset($GLOBALS['theme']);
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    if (!defined('MAINTENANCE_MODE')) {
      define('MAINTENANCE_MODE', 'error');
    }
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    drupal_maintenance_theme();
  }
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  // When running inside the testing framework, we relay the errors
  // to the tested site by the way of HTTP headers.
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  if (preg_match("/^simpletest\d+/", $_SERVER['HTTP_USER_AGENT']) && !headers_sent() && (!defined('SIMPLETEST_COLLECT_ERRORS') || SIMPLETEST_COLLECT_ERRORS)) {
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    static $number = 0;
    $assertion = array(
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      $error['%message'],
      $error['%type'],
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      array(
        'function' => $error['%function'],
        'file' => $error['%file'],
        'line' => $error['%line'],
      ),
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    );
    header('X-Drupal-Assertion-' . $number . ': ' . rawurlencode(serialize($assertion)));
    $number++;
  }

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  // Force display of error messages in update.php or if the proper error
  // reporting level is set.
  $error_level = variable_get('error_level', 2);
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  if ($error_level == 2 || ($error_level == 1 && $error['%type'] != 'Notice') || (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'update')) {
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    drupal_set_message(t('%type: %message in %function (line %line of %file).', $error), 'error');
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  }
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  try {
    watchdog('php', '%type: %message in %function (line %line of %file).', $error, WATCHDOG_ERROR);
  }
  catch (Exception $e) {
    $new_error = _drupal_decode_exception($e);
    drupal_set_message(t('%type: %message in %function (line %line of %file).', $new_error), 'error');
  }
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  if ($fatal) {
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    drupal_set_header('503 Service unavailable');
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    drupal_set_title(t('Error'));
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    if (!defined('MAINTENANCE_MODE') && drupal_get_bootstrap_phase() == DRUPAL_BOOTSTRAP_FULL) {
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      // To conserve CPU and bandwidth, omit the blocks.
      $page = drupal_get_page(t('The website encountered an unexpected error. Please try again later.'));
      $page['#show_blocks'] = FALSE;
      print drupal_render_page($page);
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    }
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    else {
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      print theme('maintenance_page', t('The website encountered an unexpected error. Please try again later.'), FALSE);
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    }
    exit;
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  }
}

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/**
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 * Gets the last caller from a backtrace.
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 *
 * @param $backtrace
 *   A standard PHP backtrace.
 * @return
 *   An associative array with keys 'file', 'line' and 'function'.
 */
function _drupal_get_last_caller($backtrace) {
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  // Errors that occur inside PHP internal functions
  // do not generate information about file and line.
  while ($backtrace && !isset($backtrace[0]['line'])) {
    array_shift($backtrace);
  }

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  // The first trace is the call itself.
  // It gives us the line and the file of the last call.
  $call = $backtrace[0];
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  // The second call give us the function where the call originated.
  if (isset($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;
}

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function _fix_gpc_magic(&$item) {
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  if (is_array($item)) {
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    array_walk($item, '_fix_gpc_magic');
  }
  else {
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    $item = stripslashes($item);
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  }
}

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/**
 * 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);
    }
  }
}

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/**
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 * Fix double-escaping problems caused by "magic quotes" in some PHP installations.
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 */
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function fix_gpc_magic() {
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  static $fixed = FALSE;
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  if (!$fixed && ini_get('magic_quotes_gpc')) {
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    array_walk($_GET, '_fix_gpc_magic');
    array_walk($_POST, '_fix_gpc_magic');
    array_walk($_COOKIE, '_fix_gpc_magic');
    array_walk($_REQUEST, '_fix_gpc_magic');
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    array_walk($_FILES, '_fix_gpc_magic_files');
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    $fixed = TRUE;
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  }
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}

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/**
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 * Translate strings to the page language or a given language.
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 *
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 * Human-readable text that will be displayed somewhere within a page should
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 * be run through the t() function.
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 *
 * 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
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 * 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.
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 *
 * 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
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 *     $message[] = t("If you don't want to receive such e-mails, you can change your settings at !url.", array('!url' => url("user/$account->uid", array('absolute' => TRUE))));
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 *   @endcode
 *
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 * - @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.
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 *   @code
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 *     drupal_set_title($title = t("@name's blog", array('@name' => $account->name)), PASS_THROUGH);
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 *   @endcode
 *
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 * - %variable, which indicates that the string should be HTML escaped and
 *   highlighted with theme_placeholder() which shows up by default as
 *   <em>emphasized</em>.
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 *   @code
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 *     $message = t('%name-from sent %name-to an e-mail.', array('%name-from' => $user->name, '%name-to' => $account->name));
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 *   @endcode
 *
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 * When using t(), try to put entire sentences and strings in one t() call.
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 * 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.
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 *
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 * Here is an example of incorrect usage of t():
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 * @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
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 *   $output .= '<p>' . t('Go to the <a href="@contact-page">contact page</a>.', array('@contact-page' => url('contact'))) . '</p>';
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 * @endcode
 *
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 * Avoid escaping quotation marks wherever possible.
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 *
 * Incorrect:
 * @code
 *   $output .= t('Don\'t click me.');
 * @endcode
 *
 * Correct:
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 * @code
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 *   $output .= t("Don't click me.");
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 * @endcode
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 *
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 * 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
 *
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 * Sample dummy file.
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 * @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()
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 * @see get_t()
 *
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 * @param $string
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 *   A string containing the English string to translate.
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 * @param $args
 *   An associative array of replacements to make after translation. Incidences
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 *   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:
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 *    - !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)
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 * @param $langcode
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 *   Optional language code to translate to a language other than what is used
 *   to display the page.
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 * @return
 *   The translated string.
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 */
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function t($string, $args = array(), $langcode = NULL) {
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  global $language;
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  static $custom_strings;

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  if (!isset($langcode)) {
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    $langcode = isset($language->language) ? $language->language : 'en';
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  }
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  // 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 $custom_strings variable to improve performance.
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  if (!isset($custom_strings[$langcode])) {
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    $custom_strings[$langcode] = variable_get('locale_custom_strings_' . $langcode, array());
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  }
  // Custom strings work for English too, even if locale module is disabled.
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  if (isset($custom_strings[$langcode][$string])) {
    $string = $custom_strings[$langcode][$string];
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  }
  // Translate with locale module if enabled.
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  elseif (function_exists('locale') && $langcode != 'en') {
    $string = locale($string, $langcode);
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  }
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  if (empty($args)) {
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    return $string;
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  }
  else {
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    // Transform arguments before inserting them.
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    foreach ($args as $key => $value) {
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      switch ($key[0]) {
        case '@':
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          // Escaped only.
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          $args[$key] = check_plain($value);
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          break;
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        case '%':
        default:
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          // Escaped and placeholder.
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          $args[$key] = theme('placeholder', $value);
          break;
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        case '!':
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          // Pass-through.
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      }
    }
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    return strtr($string, $args);
  }
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}

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/**
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 * @defgroup validation Input validation
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 * @{
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 * Functions to validate user input.
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 */

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/**
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 * Verify the syntax of the given e-mail address.
 *
 * Empty e-mail addresses are allowed. See RFC 2822 for details.
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 *
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 * @param $mail
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 *   A string containing an e-mail address.
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 * @return
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 *   TRUE if the address is in a valid format.
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 */
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function valid_email_address($mail) {
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