diff -r 07239de796bb -r e756a8c72c3d cms/drupal/includes/bootstrap.inc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/includes/bootstrap.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,3851 @@
+<?php
+
+/**
+ * @file
+ * Functions that need to be loaded on every Drupal request.
+ */
+
+/**
+ * The current system version.
+ */
+define('VERSION', '7.56');
+
+/**
+ * Core API compatibility.
+ */
+define('DRUPAL_CORE_COMPATIBILITY', '7.x');
+
+/**
+ * Minimum supported version of PHP.
+ */
+define('DRUPAL_MINIMUM_PHP', '5.2.4');
+
+/**
+ * Minimum recommended value of PHP memory_limit.
+ */
+define('DRUPAL_MINIMUM_PHP_MEMORY_LIMIT', '32M');
+
+/**
+ * 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);
+
+/**
+ * Indicates that the item should never be removed unless explicitly selected.
+ *
+ * The item may be removed using cache_clear_all() with a cache ID.
+ */
+define('CACHE_PERMANENT', 0);
+
+/**
+ * Indicates that the item should be removed at the next general cache wipe.
+ */
+define('CACHE_TEMPORARY', -1);
+
+/**
+ * @defgroup logging_severity_levels Logging severity levels
+ * @{
+ * Logging severity levels as defined in RFC 3164.
+ *
+ * The WATCHDOG_* constant definitions correspond to the logging severity levels
+ * defined in RFC 3164, section 4.1.1. PHP supplies predefined LOG_* constants
+ * for use in the syslog() function, but their values on Windows builds do not
+ * correspond to RFC 3164. The associated PHP bug report was closed with the
+ * comment, "And it's also not a bug, as Windows just have less log levels,"
+ * and "So the behavior you're seeing is perfectly normal."
+ *
+ * @see http://www.faqs.org/rfcs/rfc3164.html
+ * @see http://bugs.php.net/bug.php?id=18090
+ * @see http://php.net/manual/function.syslog.php
+ * @see http://php.net/manual/network.constants.php
+ * @see watchdog()
+ * @see watchdog_severity_levels()
+ */
+
+/**
+ * Log message severity -- Emergency: system is unusable.
+ */
+define('WATCHDOG_EMERGENCY', 0);
+
+/**
+ * Log message severity -- Alert: action must be taken immediately.
+ */
+define('WATCHDOG_ALERT', 1);
+
+/**
+ * Log message severity -- Critical conditions.
+ */
+define('WATCHDOG_CRITICAL', 2);
+
+/**
+ * Log message severity -- Error conditions.
+ */
+define('WATCHDOG_ERROR', 3);
+
+/**
+ * Log message severity -- Warning conditions.
+ */
+define('WATCHDOG_WARNING', 4);
+
+/**
+ * Log message severity -- Normal but significant conditions.
+ */
+define('WATCHDOG_NOTICE', 5);
+
+/**
+ * Log message severity -- Informational messages.
+ */
+define('WATCHDOG_INFO', 6);
+
+/**
+ * Log message severity -- Debug-level messages.
+ */
+define('WATCHDOG_DEBUG', 7);
+
+/**
+ * @} End of "defgroup logging_severity_levels".
+ */
+
+/**
+ * First bootstrap phase: initialize configuration.
+ */
+define('DRUPAL_BOOTSTRAP_CONFIGURATION', 0);
+
+/**
+ * Second bootstrap phase: try to serve a cached page.
+ */
+define('DRUPAL_BOOTSTRAP_PAGE_CACHE', 1);
+
+/**
+ * Third bootstrap phase: initialize database layer.
+ */
+define('DRUPAL_BOOTSTRAP_DATABASE', 2);
+
+/**
+ * Fourth bootstrap phase: initialize the variable system.
+ */
+define('DRUPAL_BOOTSTRAP_VARIABLES', 3);
+
+/**
+ * Fifth bootstrap phase: initialize session handling.
+ */
+define('DRUPAL_BOOTSTRAP_SESSION', 4);
+
+/**
+ * Sixth bootstrap phase: set up the page header.
+ */
+define('DRUPAL_BOOTSTRAP_PAGE_HEADER', 5);
+
+/**
+ * Seventh bootstrap phase: find out language of the page.
+ */
+define('DRUPAL_BOOTSTRAP_LANGUAGE', 6);
+
+/**
+ * Final bootstrap phase: Drupal is fully loaded; validate and fix input data.
+ */
+define('DRUPAL_BOOTSTRAP_FULL', 7);
+
+/**
+ * Role ID for anonymous users; should match what's in the "role" table.
+ */
+define('DRUPAL_ANONYMOUS_RID', 1);
+
+/**
+ * Role ID for authenticated users; should match what's in the "role" table.
+ */
+define('DRUPAL_AUTHENTICATED_RID', 2);
+
+/**
+ * The number of bytes in a kilobyte.
+ *
+ * For more information, visit http://en.wikipedia.org/wiki/Kilobyte.
+ */
+define('DRUPAL_KILOBYTE', 1024);
+
+/**
+ * The language code used when no language is explicitly assigned.
+ *
+ * Defined by ISO639-2 for "Undetermined".
+ */
+define('LANGUAGE_NONE', 'und');
+
+/**
+ * The type of language used to define the content language.
+ */
+define('LANGUAGE_TYPE_CONTENT', 'language_content');
+
+/**
+ * The type of language used to select the user interface.
+ */
+define('LANGUAGE_TYPE_INTERFACE', 'language');
+
+/**
+ * The type of language used for URLs.
+ */
+define('LANGUAGE_TYPE_URL', 'language_url');
+
+/**
+ * Language written left to right. Possible value of $language->direction.
+ */
+define('LANGUAGE_LTR', 0);
+
+/**
+ * Language written right to left. Possible value of $language->direction.
+ */
+define('LANGUAGE_RTL', 1);
+
+/**
+ * Time of the current request in seconds elapsed since the Unix Epoch.
+ *
+ * This differs from $_SERVER['REQUEST_TIME'], which is stored as a float
+ * since PHP 5.4.0. Float timestamps confuse most PHP functions
+ * (including date_create()).
+ *
+ * @see http://php.net/manual/reserved.variables.server.php
+ * @see http://php.net/manual/function.time.php
+ */
+define('REQUEST_TIME', (int) $_SERVER['REQUEST_TIME']);
+
+/**
+ * Flag used to indicate that text is not sanitized, so run check_plain().
+ *
+ * @see drupal_set_title()
+ */
+define('CHECK_PLAIN', 0);
+
+/**
+ * Flag used to indicate that text has already been sanitized.
+ *
+ * @see drupal_set_title()
+ */
+define('PASS_THROUGH', -1);
+
+/**
+ * Signals that the registry lookup cache should be reset.
+ */
+define('REGISTRY_RESET_LOOKUP_CACHE', 1);
+
+/**
+ * Signals that the registry lookup cache should be written to storage.
+ */
+define('REGISTRY_WRITE_LOOKUP_CACHE', 2);
+
+/**
+ * Regular expression to match PHP function names.
+ *
+ * @see http://php.net/manual/language.functions.php
+ */
+define('DRUPAL_PHP_FUNCTION_PATTERN', '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*');
+
+/**
+ * A RFC7231 Compliant date.
+ *
+ * http://tools.ietf.org/html/rfc7231#section-7.1.1.1
+ *
+ * Example: Sun, 06 Nov 1994 08:49:37 GMT
+ *
+ * This constant was introduced in PHP 7.0.19 and PHP 7.1.5 but needs to be
+ * defined by Drupal for earlier PHP versions.
+ */
+if (!defined('DATE_RFC7231')) {
+  define('DATE_RFC7231', 'D, d M Y H:i:s \G\M\T');
+}
+
+/**
+ * Provides a caching wrapper to be used in place of large array structures.
+ *
+ * This class should be extended by systems that need to cache large amounts
+ * of data and have it represented as an array to calling functions. These
+ * arrays can become very large, so ArrayAccess is used to allow different
+ * strategies to be used for caching internally (lazy loading, building caches
+ * over time etc.). This can dramatically reduce the amount of data that needs
+ * to be loaded from cache backends on each request, and memory usage from
+ * static caches of that same data.
+ *
+ * Note that array_* functions do not work with ArrayAccess. Systems using
+ * DrupalCacheArray should use this only internally. If providing API functions
+ * that return the full array, this can be cached separately or returned
+ * directly. However since DrupalCacheArray holds partial content by design, it
+ * should be a normal PHP array or otherwise contain the full structure.
+ *
+ * Note also that due to limitations in PHP prior to 5.3.4, it is impossible to
+ * write directly to the contents of nested arrays contained in this object.
+ * Only writes to the top-level array elements are possible. So if you
+ * previously had set $object['foo'] = array(1, 2, 'bar' => 'baz'), but later
+ * want to change the value of 'bar' from 'baz' to 'foobar', you cannot do so
+ * a targeted write like $object['foo']['bar'] = 'foobar'. Instead, you must
+ * overwrite the entire top-level 'foo' array with the entire set of new
+ * values: $object['foo'] = array(1, 2, 'bar' => 'foobar'). Due to this same
+ * limitation, attempts to create references to any contained data, nested or
+ * otherwise, will fail silently. So $var = &$object['foo'] will not throw an
+ * error, and $var will be populated with the contents of $object['foo'], but
+ * that data will be passed by value, not reference. For more information on
+ * the PHP limitation, see the note in the official PHP documentation at·
+ * http://php.net/manual/arrayaccess.offsetget.php on
+ * ArrayAccess::offsetGet().
+ *
+ * By default, the class accounts for caches where calling functions might
+ * request keys in the array that won't exist even after a cache rebuild. This
+ * prevents situations where a cache rebuild would be triggered over and over
+ * due to a 'missing' item. These cases are stored internally as a value of
+ * NULL. This means that the offsetGet() and offsetExists() methods
+ * must be overridden if caching an array where the top level values can
+ * legitimately be NULL, and where $object->offsetExists() needs to correctly
+ * return (equivalent to array_key_exists() vs. isset()). This should not
+ * be necessary in the majority of cases.
+ *
+ * Classes extending this class must override at least the
+ * resolveCacheMiss() method to have a working implementation.
+ *
+ * offsetSet() is not overridden by this class by default. In practice this
+ * means that assigning an offset via arrayAccess will only apply while the
+ * object is in scope and will not be written back to the persistent cache.
+ * This follows a similar pattern to static vs. persistent caching in
+ * procedural code. Extending classes may wish to alter this behavior, for
+ * example by overriding offsetSet() and adding an automatic call to persist().
+ *
+ * @see SchemaCache
+ */
+abstract class DrupalCacheArray implements ArrayAccess {
+
+  /**
+   * A cid to pass to cache_set() and cache_get().
+   */
+  protected $cid;
+
+  /**
+   * A bin to pass to cache_set() and cache_get().
+   */
+  protected $bin;
+
+  /**
+   * An array of keys to add to the cache at the end of the request.
+   */
+  protected $keysToPersist = array();
+
+  /**
+   * Storage for the data itself.
+   */
+  protected $storage = array();
+
+  /**
+   * Constructs a DrupalCacheArray object.
+   *
+   * @param $cid
+   *   The cid for the array being cached.
+   * @param $bin
+   *   The bin to cache the array.
+   */
+  public function __construct($cid, $bin) {
+    $this->cid = $cid;
+    $this->bin = $bin;
+
+    if ($cached = cache_get($this->cid, $this->bin)) {
+     $this->storage = $cached->data;
+    }
+  }
+
+  /**
+   * Implements ArrayAccess::offsetExists().
+   */
+  public function offsetExists($offset) {
+    return $this->offsetGet($offset) !== NULL;
+  }
+
+  /**
+   * Implements ArrayAccess::offsetGet().
+   */
+  public function offsetGet($offset) {
+    if (isset($this->storage[$offset]) || array_key_exists($offset, $this->storage)) {
+      return $this->storage[$offset];
+    }
+    else {
+      return $this->resolveCacheMiss($offset);
+    }
+  }
+
+  /**
+   * Implements ArrayAccess::offsetSet().
+   */
+  public function offsetSet($offset, $value) {
+    $this->storage[$offset] = $value;
+  }
+
+  /**
+   * Implements ArrayAccess::offsetUnset().
+   */
+  public function offsetUnset($offset) {
+    unset($this->storage[$offset]);
+  }
+
+  /**
+   * Flags an offset value to be written to the persistent cache.
+   *
+   * If a value is assigned to a cache object with offsetSet(), by default it
+   * will not be written to the persistent cache unless it is flagged with this
+   * method. This allows items to be cached for the duration of a request,
+   * without necessarily writing back to the persistent cache at the end.
+   *
+   * @param $offset
+   *   The array offset that was requested.
+   * @param $persist
+   *   Optional boolean to specify whether the offset should be persisted or
+   *   not, defaults to TRUE. When called with $persist = FALSE the offset will
+   *   be unflagged so that it will not be written at the end of the request.
+   */
+  protected function persist($offset, $persist = TRUE) {
+    $this->keysToPersist[$offset] = $persist;
+  }
+
+  /**
+   * Resolves a cache miss.
+   *
+   * When an offset is not found in the object, this is treated as a cache
+   * miss. This method allows classes implementing the interface to look up
+   * the actual value and allow it to be cached.
+   *
+   * @param $offset
+   *   The offset that was requested.
+   *
+   * @return
+   *   The value of the offset, or NULL if no value was found.
+   */
+  abstract protected function resolveCacheMiss($offset);
+
+  /**
+   * Writes a value to the persistent cache immediately.
+   *
+   * @param $data
+   *   The data to write to the persistent cache.
+   * @param $lock
+   *   Whether to acquire a lock before writing to cache.
+   */
+  protected function set($data, $lock = TRUE) {
+    // Lock cache writes to help avoid stampedes.
+    // To implement locking for cache misses, override __construct().
+    $lock_name = $this->cid . ':' . $this->bin;
+    if (!$lock || lock_acquire($lock_name)) {
+      if ($cached = cache_get($this->cid, $this->bin)) {
+        $data = $cached->data + $data;
+      }
+      cache_set($this->cid, $data, $this->bin);
+      if ($lock) {
+        lock_release($lock_name);
+      }
+    }
+  }
+
+  /**
+   * Destructs the DrupalCacheArray object.
+   */
+  public function __destruct() {
+    $data = array();
+    foreach ($this->keysToPersist as $offset => $persist) {
+      if ($persist) {
+        $data[$offset] = $this->storage[$offset];
+      }
+    }
+    if (!empty($data)) {
+      $this->set($data);
+    }
+  }
+}
+
+/**
+ * Starts the timer with the specified name.
+ *
+ * If you start and stop the same timer multiple times, the measured intervals
+ * will be accumulated.
+ *
+ * @param $name
+ *   The name of the timer.
+ */
+function timer_start($name) {
+  global $timers;
+
+  $timers[$name]['start'] = microtime(TRUE);
+  $timers[$name]['count'] = isset($timers[$name]['count']) ? ++$timers[$name]['count'] : 1;
+}
+
+/**
+ * Reads the current timer value without stopping the timer.
+ *
+ * @param $name
+ *   The name of the timer.
+ *
+ * @return
+ *   The current timer value in ms.
+ */
+function timer_read($name) {
+  global $timers;
+
+  if (isset($timers[$name]['start'])) {
+    $stop = microtime(TRUE);
+    $diff = round(($stop - $timers[$name]['start']) * 1000, 2);
+
+    if (isset($timers[$name]['time'])) {
+      $diff += $timers[$name]['time'];
+    }
+    return $diff;
+  }
+  return $timers[$name]['time'];
+}
+
+/**
+ * Stops the timer with the specified name.
+ *
+ * @param $name
+ *   The name of the timer.
+ *
+ * @return
+ *   A timer array. The array contains the number of times the timer has been
+ *   started and stopped (count) and the accumulated timer value in ms (time).
+ */
+function timer_stop($name) {
+  global $timers;
+
+  if (isset($timers[$name]['start'])) {
+    $stop = microtime(TRUE);
+    $diff = round(($stop - $timers[$name]['start']) * 1000, 2);
+    if (isset($timers[$name]['time'])) {
+      $timers[$name]['time'] += $diff;
+    }
+    else {
+      $timers[$name]['time'] = $diff;
+    }
+    unset($timers[$name]['start']);
+  }
+
+  return $timers[$name];
+}
+
+/**
+ * Returns the appropriate configuration directory.
+ *
+ * Returns the configuration path based on the site's hostname, port, and
+ * pathname. See default.settings.php for examples on how the URL is converted
+ * to a directory.
+ *
+ * @param bool $require_settings
+ *   Only configuration directories with an existing settings.php file
+ *   will be recognized. Defaults to TRUE. During initial installation,
+ *   this is set to FALSE so that Drupal can detect a matching directory,
+ *   then create a new settings.php file in it.
+ * @param bool $reset
+ *   Force a full search for matching directories even if one had been
+ *   found previously. Defaults to FALSE.
+ *
+ * @return
+ *   The path of the matching directory.
+ *
+ * @see default.settings.php
+ */
+function conf_path($require_settings = TRUE, $reset = FALSE) {
+  $conf = &drupal_static(__FUNCTION__, '');
+
+  if ($conf && !$reset) {
+    return $conf;
+  }
+
+  $confdir = 'sites';
+
+  $sites = array();
+  if (file_exists(DRUPAL_ROOT . '/' . $confdir . '/sites.php')) {
+    // This will overwrite $sites with the desired mappings.
+    include(DRUPAL_ROOT . '/' . $confdir . '/sites.php');
+  }
+
+  $uri = explode('/', $_SERVER['SCRIPT_NAME'] ? $_SERVER['SCRIPT_NAME'] : $_SERVER['SCRIPT_FILENAME']);
+  $server = explode('.', implode('.', array_reverse(explode(':', rtrim($_SERVER['HTTP_HOST'], '.')))));
+  for ($i = count($uri) - 1; $i > 0; $i--) {
+    for ($j = count($server); $j > 0; $j--) {
+      $dir = implode('.', array_slice($server, -$j)) . implode('.', array_slice($uri, 0, $i));
+      if (isset($sites[$dir]) && file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $sites[$dir])) {
+        $dir = $sites[$dir];
+      }
+      if (file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $dir . '/settings.php') || (!$require_settings && file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $dir))) {
+        $conf = "$confdir/$dir";
+        return $conf;
+      }
+    }
+  }
+  $conf = "$confdir/default";
+  return $conf;
+}
+
+/**
+ * Sets appropriate server variables needed for command line scripts to work.
+ *
+ * This function can be called by command line scripts before bootstrapping
+ * Drupal, to ensure that the page loads with the desired server parameters.
+ * This is because many parts of Drupal assume that they are running in a web
+ * browser and therefore use information from the global PHP $_SERVER variable
+ * that does not get set when Drupal is run from the command line.
+ *
+ * In many cases, the default way in which this function populates the $_SERVER
+ * variable is sufficient, and it can therefore be called without passing in
+ * any input. However, command line scripts running on a multisite installation
+ * (or on any installation that has settings.php stored somewhere other than
+ * the sites/default folder) need to pass in the URL of the site to allow
+ * Drupal to detect the correct location of the settings.php file. Passing in
+ * the 'url' parameter is also required for functions like request_uri() to
+ * return the expected values.
+ *
+ * Most other parameters do not need to be passed in, but may be necessary in
+ * some cases; for example, if Drupal's ip_address() function needs to return
+ * anything but the standard localhost value ('127.0.0.1'), the command line
+ * script should pass in the desired value via the 'REMOTE_ADDR' key.
+ *
+ * @param $variables
+ *   (optional) An associative array of variables within $_SERVER that should
+ *   be replaced. If the special element 'url' is provided in this array, it
+ *   will be used to populate some of the server defaults; it should be set to
+ *   the URL of the current page request, excluding any $_GET request but
+ *   including the script name (e.g., http://www.example.com/mysite/index.php).
+ *
+ * @see conf_path()
+ * @see request_uri()
+ * @see ip_address()
+ */
+function drupal_override_server_variables($variables = array()) {
+  // Allow the provided URL to override any existing values in $_SERVER.
+  if (isset($variables['url'])) {
+    $url = parse_url($variables['url']);
+    if (isset($url['host'])) {
+      $_SERVER['HTTP_HOST'] = $url['host'];
+    }
+    if (isset($url['path'])) {
+      $_SERVER['SCRIPT_NAME'] = $url['path'];
+    }
+    unset($variables['url']);
+  }
+  // Define default values for $_SERVER keys. These will be used if $_SERVER
+  // does not already define them and no other values are passed in to this
+  // function.
+  $defaults = array(
+    'HTTP_HOST' => 'localhost',
+    'SCRIPT_NAME' => NULL,
+    'REMOTE_ADDR' => '127.0.0.1',
+    'REQUEST_METHOD' => 'GET',
+    'SERVER_NAME' => NULL,
+    'SERVER_SOFTWARE' => NULL,
+    'HTTP_USER_AGENT' => NULL,
+  );
+  // Replace elements of the $_SERVER array, as appropriate.
+  $_SERVER = $variables + $_SERVER + $defaults;
+}
+
+/**
+ * Initializes the PHP environment.
+ */
+function drupal_environment_initialize() {
+  if (!isset($_SERVER['HTTP_REFERER'])) {
+    $_SERVER['HTTP_REFERER'] = '';
+  }
+  if (!isset($_SERVER['SERVER_PROTOCOL']) || ($_SERVER['SERVER_PROTOCOL'] != 'HTTP/1.0' && $_SERVER['SERVER_PROTOCOL'] != 'HTTP/1.1')) {
+    $_SERVER['SERVER_PROTOCOL'] = 'HTTP/1.0';
+  }
+
+  if (isset($_SERVER['HTTP_HOST'])) {
+    // As HTTP_HOST is user input, ensure it only contains characters allowed
+    // in hostnames. See RFC 952 (and RFC 2181).
+    // $_SERVER['HTTP_HOST'] is lowercased here per specifications.
+    $_SERVER['HTTP_HOST'] = strtolower($_SERVER['HTTP_HOST']);
+    if (!drupal_valid_http_host($_SERVER['HTTP_HOST'])) {
+      // HTTP_HOST is invalid, e.g. if containing slashes it may be an attack.
+      header($_SERVER['SERVER_PROTOCOL'] . ' 400 Bad Request');
+      exit;
+    }
+  }
+  else {
+    // Some pre-HTTP/1.1 clients will not send a Host header. Ensure the key is
+    // defined for E_ALL compliance.
+    $_SERVER['HTTP_HOST'] = '';
+  }
+
+  // When clean URLs are enabled, emulate ?q=foo/bar using REQUEST_URI. It is
+  // not possible to append the query string using mod_rewrite without the B
+  // flag (this was added in Apache 2.2.8), because mod_rewrite unescapes the
+  // path before passing it on to PHP. This is a problem when the path contains
+  // e.g. "&" or "%" that have special meanings in URLs and must be encoded.
+  $_GET['q'] = request_path();
+
+  // Enforce E_ALL, but allow users to set levels not part of E_ALL.
+  error_reporting(E_ALL | error_reporting());
+
+  // Override PHP settings required for Drupal to work properly.
+  // sites/default/default.settings.php contains more runtime settings.
+  // The .htaccess file contains settings that cannot be changed at runtime.
+
+  // Don't escape quotes when reading files from the database, disk, etc.
+  ini_set('magic_quotes_runtime', '0');
+  // Use session cookies, not transparent sessions that puts the session id in
+  // the query string.
+  ini_set('session.use_cookies', '1');
+  ini_set('session.use_only_cookies', '1');
+  ini_set('session.use_trans_sid', '0');
+  // Don't send HTTP headers using PHP's session handler.
+  // An empty string is used here to disable the cache limiter.
+  ini_set('session.cache_limiter', '');
+  // Use httponly session cookies.
+  ini_set('session.cookie_httponly', '1');
+
+  // Set sane locale settings, to ensure consistent string, dates, times and
+  // numbers handling.
+  setlocale(LC_ALL, 'C');
+}
+
+/**
+ * Validates that a hostname (for example $_SERVER['HTTP_HOST']) is safe.
+ *
+ * @return
+ *  TRUE if only containing valid characters, or FALSE otherwise.
+ */
+function drupal_valid_http_host($host) {
+  // Limit the length of the host name to 1000 bytes to prevent DoS attacks with
+  // long host names.
+  return strlen($host) <= 1000
+    // Limit the number of subdomains and port separators to prevent DoS attacks
+    // in conf_path().
+    && substr_count($host, '.') <= 100
+    && substr_count($host, ':') <= 100
+    && preg_match('/^\[?(?:[a-zA-Z0-9-:\]_]+\.?)+$/', $host);
+}
+
+/**
+ * Checks whether an HTTPS request is being served.
+ *
+ * @return bool
+ *   TRUE if the request is HTTPS, FALSE otherwise.
+ */
+function drupal_is_https() {
+  return isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on';
+}
+
+/**
+ * Sets the base URL, cookie domain, and session name from configuration.
+ */
+function drupal_settings_initialize() {
+  global $base_url, $base_path, $base_root;
+
+  // Export these settings.php variables to the global namespace.
+  global $databases, $cookie_domain, $conf, $installed_profile, $update_free_access, $db_url, $db_prefix, $drupal_hash_salt, $is_https, $base_secure_url, $base_insecure_url;
+  $conf = array();
+
+  if (file_exists(DRUPAL_ROOT . '/' . conf_path() . '/settings.php')) {
+    include_once DRUPAL_ROOT . '/' . conf_path() . '/settings.php';
+  }
+  $is_https = drupal_is_https();
+
+  if (isset($base_url)) {
+    // Parse fixed base URL from settings.php.
+    $parts = parse_url($base_url);
+    if (!isset($parts['path'])) {
+      $parts['path'] = '';
+    }
+    $base_path = $parts['path'] . '/';
+    // Build $base_root (everything until first slash after "scheme://").
+    $base_root = substr($base_url, 0, strlen($base_url) - strlen($parts['path']));
+  }
+  else {
+    // Create base URL.
+    $http_protocol = $is_https ? 'https' : 'http';
+    $base_root = $http_protocol . '://' . $_SERVER['HTTP_HOST'];
+
+    $base_url = $base_root;
+
+    // $_SERVER['SCRIPT_NAME'] can, in contrast to $_SERVER['PHP_SELF'], not
+    // be modified by a visitor.
+    if ($dir = rtrim(dirname($_SERVER['SCRIPT_NAME']), '\/')) {
+      $base_path = $dir;
+      $base_url .= $base_path;
+      $base_path .= '/';
+    }
+    else {
+      $base_path = '/';
+    }
+  }
+  $base_secure_url = str_replace('http://', 'https://', $base_url);
+  $base_insecure_url = str_replace('https://', 'http://', $base_url);
+
+  if ($cookie_domain) {
+    // If the user specifies the cookie domain, also use it for session name.
+    $session_name = $cookie_domain;
+  }
+  else {
+    // Otherwise use $base_url as session name, without the protocol
+    // to use the same session identifiers across HTTP and HTTPS.
+    list( , $session_name) = explode('://', $base_url, 2);
+    // HTTP_HOST can be modified by a visitor, but we already sanitized it
+    // in drupal_settings_initialize().
+    if (!empty($_SERVER['HTTP_HOST'])) {
+      $cookie_domain = $_SERVER['HTTP_HOST'];
+      // Strip leading periods, www., and port numbers from cookie domain.
+      $cookie_domain = ltrim($cookie_domain, '.');
+      if (strpos($cookie_domain, 'www.') === 0) {
+        $cookie_domain = substr($cookie_domain, 4);
+      }
+      $cookie_domain = explode(':', $cookie_domain);
+      $cookie_domain = '.' . $cookie_domain[0];
+    }
+  }
+  // Per RFC 2109, cookie domains must contain at least one dot other than the
+  // first. For hosts such as 'localhost' or IP Addresses we don't set a cookie domain.
+  if (count(explode('.', $cookie_domain)) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
+    ini_set('session.cookie_domain', $cookie_domain);
+  }
+  // To prevent session cookies from being hijacked, a user can configure the
+  // SSL version of their website to only transfer session cookies via SSL by
+  // using PHP's session.cookie_secure setting. The browser will then use two
+  // separate session cookies for the HTTPS and HTTP versions of the site. So we
+  // must use different session identifiers for HTTPS and HTTP to prevent a
+  // cookie collision.
+  if ($is_https) {
+    ini_set('session.cookie_secure', TRUE);
+  }
+  $prefix = ini_get('session.cookie_secure') ? 'SSESS' : 'SESS';
+  session_name($prefix . substr(hash('sha256', $session_name), 0, 32));
+}
+
+/**
+ * Returns and optionally sets the filename for a system resource.
+ *
+ * The filename, whether provided, cached, or retrieved from the database, is
+ * only returned if the file exists.
+ *
+ * This function plays a key role in allowing Drupal's resources (modules
+ * and themes) to be located in different places depending on a site's
+ * configuration. For example, a module 'foo' may legally be located
+ * in any of these three places:
+ *
+ * modules/foo/foo.module
+ * sites/all/modules/foo/foo.module
+ * sites/example.com/modules/foo/foo.module
+ *
+ * Calling drupal_get_filename('module', 'foo') will give you one of
+ * the above, depending on where the module is located.
+ *
+ * @param $type
+ *   The type of the item (theme, theme_engine, module, profile).
+ * @param $name
+ *   The name of the item for which the filename is requested.
+ * @param $filename
+ *   The filename of the item if it is to be set explicitly rather
+ *   than by consulting the database.
+ * @param bool $trigger_error
+ *   Whether to trigger an error when a file is missing or has unexpectedly
+ *   moved. This defaults to TRUE, but can be set to FALSE by calling code that
+ *   merely wants to check whether an item exists in the filesystem.
+ *
+ * @return
+ *   The filename of the requested item or NULL if the item is not found.
+ */
+function drupal_get_filename($type, $name, $filename = NULL, $trigger_error = TRUE) {
+  // The $files static variable will hold the locations of all requested files.
+  // We can be sure that any file listed in this static variable actually
+  // exists as all additions have gone through a file_exists() check.
+  // The location of files will not change during the request, so do not use
+  // drupal_static().
+  static $files = array();
+
+  // Profiles are a special case: they have a fixed location and naming.
+  if ($type == 'profile') {
+    $profile_filename = "profiles/$name/$name.profile";
+    $files[$type][$name] = file_exists($profile_filename) ? $profile_filename : FALSE;
+  }
+  if (!isset($files[$type])) {
+    $files[$type] = array();
+  }
+
+  if (!empty($filename) && file_exists($filename)) {
+    // Prime the static cache with the provided filename.
+    $files[$type][$name] = $filename;
+  }
+  elseif (isset($files[$type][$name])) {
+    // This item had already been found earlier in the request, either through
+    // priming of the static cache (for example, in system_list()), through a
+    // lookup in the {system} table, or through a file scan (cached or not). Do
+    // nothing.
+  }
+  else {
+    // Look for the filename listed in the {system} table. Verify that we have
+    // an active database connection before doing so, since this function is
+    // called both before we have a database connection (i.e. during
+    // installation) and when a database connection fails.
+    $database_unavailable = TRUE;
+    try {
+      if (function_exists('db_query')) {
+        $file = db_query("SELECT filename FROM {system} WHERE name = :name AND type = :type", array(':name' => $name, ':type' => $type))->fetchField();
+        if ($file !== FALSE && file_exists(DRUPAL_ROOT . '/' . $file)) {
+          $files[$type][$name] = $file;
+        }
+        $database_unavailable = FALSE;
+      }
+    }
+    catch (Exception $e) {
+      // The database table may not exist because Drupal is not yet installed,
+      // the database might be down, or we may have done a non-database cache
+      // flush while $conf['page_cache_without_database'] = TRUE and
+      // $conf['page_cache_invoke_hooks'] = TRUE. We have a fallback for these
+      // cases so we hide the error completely.
+    }
+    // Fall back to searching the filesystem if the database could not find the
+    // file or the file does not exist at the path returned by the database.
+    if (!isset($files[$type][$name])) {
+      $files[$type][$name] = _drupal_get_filename_fallback($type, $name, $trigger_error, $database_unavailable);
+    }
+  }
+
+  if (isset($files[$type][$name])) {
+    return $files[$type][$name];
+  }
+}
+
+/**
+ * Performs a cached file system scan as a fallback when searching for a file.
+ *
+ * This function looks for the requested file by triggering a file scan,
+ * caching the new location if the file has moved and caching the miss
+ * if the file is missing. If a file had been marked as missing in a previous
+ * file scan, or if it has been marked as moved and is still in the last known
+ * location, no new file scan will be performed.
+ *
+ * @param string $type
+ *   The type of the item (theme, theme_engine, module, profile).
+ * @param string $name
+ *   The name of the item for which the filename is requested.
+ * @param bool $trigger_error
+ *   Whether to trigger an error when a file is missing or has unexpectedly
+ *   moved.
+ * @param bool $database_unavailable
+ *   Whether this function is being called because the Drupal database could
+ *   not be queried for the file's location.
+ *
+ * @return
+ *   The filename of the requested item or NULL if the item is not found.
+ *
+ * @see drupal_get_filename()
+ */
+function _drupal_get_filename_fallback($type, $name, $trigger_error, $database_unavailable) {
+  $file_scans = &_drupal_file_scan_cache();
+  $filename = NULL;
+
+  // If the cache indicates that the item is missing, or we can verify that the
+  // item exists in the location the cache says it exists in, use that.
+  if (isset($file_scans[$type][$name]) && ($file_scans[$type][$name] === FALSE || file_exists($file_scans[$type][$name]))) {
+    $filename = $file_scans[$type][$name];
+  }
+  // Otherwise, perform a new file scan to find the item.
+  else {
+    $filename = _drupal_get_filename_perform_file_scan($type, $name);
+    // Update the static cache, and mark the persistent cache for updating at
+    // the end of the page request. See drupal_file_scan_write_cache().
+    $file_scans[$type][$name] = $filename;
+    $file_scans['#write_cache'] = TRUE;
+  }
+
+  // If requested, trigger a user-level warning about the missing or
+  // unexpectedly moved file. If the database was unavailable, do not trigger a
+  // warning in the latter case, though, since if the {system} table could not
+  // be queried there is no way to know if the location found here was
+  // "unexpected" or not.
+  if ($trigger_error) {
+    $error_type = $filename === FALSE ? 'missing' : 'moved';
+    if ($error_type == 'missing' || !$database_unavailable) {
+      _drupal_get_filename_fallback_trigger_error($type, $name, $error_type);
+    }
+  }
+
+  // The cache stores FALSE for files that aren't found (to be able to
+  // distinguish them from files that have not yet been searched for), but
+  // drupal_get_filename() expects NULL for these instead, so convert to NULL
+  // before returning.
+  if ($filename === FALSE) {
+    $filename = NULL;
+  }
+  return $filename;
+}
+
+/**
+ * Returns the current list of cached file system scan results.
+ *
+ * @return
+ *   An associative array tracking the most recent file scan results for all
+ *   files that have had scans performed. The keys are the type and name of the
+ *   item that was searched for, and the values can be either:
+ *   - Boolean FALSE if the item was not found in the file system.
+ *   - A string pointing to the location where the item was found.
+ */
+function &_drupal_file_scan_cache() {
+  $file_scans = &drupal_static(__FUNCTION__, array());
+
+  // The file scan results are stored in a persistent cache (in addition to the
+  // static cache) but because this function can be called before the
+  // persistent cache is available, we must merge any items that were found
+  // earlier in the page request into the results from the persistent cache.
+  if (!isset($file_scans['#cache_merge_done'])) {
+    try {
+      if (function_exists('cache_get')) {
+        $cache = cache_get('_drupal_file_scan_cache', 'cache_bootstrap');
+        if (!empty($cache->data)) {
+          // File scan results from the current request should take precedence
+          // over the results from the persistent cache, since they are newer.
+          $file_scans = drupal_array_merge_deep($cache->data, $file_scans);
+        }
+        // Set a flag to indicate that the persistent cache does not need to be
+        // merged again.
+        $file_scans['#cache_merge_done'] = TRUE;
+      }
+    }
+    catch (Exception $e) {
+      // Hide the error.
+    }
+  }
+
+  return $file_scans;
+}
+
+/**
+ * Performs a file system scan to search for a system resource.
+ *
+ * @param $type
+ *   The type of the item (theme, theme_engine, module, profile).
+ * @param $name
+ *   The name of the item for which the filename is requested.
+ *
+ * @return
+ *   The filename of the requested item or FALSE if the item is not found.
+ *
+ * @see drupal_get_filename()
+ * @see _drupal_get_filename_fallback()
+ */
+function _drupal_get_filename_perform_file_scan($type, $name) {
+  // The location of files will not change during the request, so do not use
+  // drupal_static().
+  static $dirs = array(), $files = array();
+
+  // We have a consistent directory naming: modules, themes...
+  $dir = $type . 's';
+  if ($type == 'theme_engine') {
+    $dir = 'themes/engines';
+    $extension = 'engine';
+  }
+  elseif ($type == 'theme') {
+    $extension = 'info';
+  }
+  else {
+    $extension = $type;
+  }
+
+  // Check if we had already scanned this directory/extension combination.
+  if (!isset($dirs[$dir][$extension])) {
+    // Log that we have now scanned this directory/extension combination
+    // into a static variable so as to prevent unnecessary file scans.
+    $dirs[$dir][$extension] = TRUE;
+    if (!function_exists('drupal_system_listing')) {
+      require_once DRUPAL_ROOT . '/includes/common.inc';
+    }
+    // Scan the appropriate directories for all files with the requested
+    // extension, not just the file we are currently looking for. This
+    // prevents unnecessary scans from being repeated when this function is
+    // called more than once in the same page request.
+    $matches = drupal_system_listing("/^" . DRUPAL_PHP_FUNCTION_PATTERN . "\.$extension$/", $dir, 'name', 0);
+    foreach ($matches as $matched_name => $file) {
+      // Log the locations found in the file scan into a static variable.
+      $files[$type][$matched_name] = $file->uri;
+    }
+  }
+
+  // Return the results of the file system scan, or FALSE to indicate the file
+  // was not found.
+  return isset($files[$type][$name]) ? $files[$type][$name] : FALSE;
+}
+
+/**
+ * Triggers a user-level warning for missing or unexpectedly moved files.
+ *
+ * @param $type
+ *   The type of the item (theme, theme_engine, module, profile).
+ * @param $name
+ *   The name of the item for which the filename is requested.
+ * @param $error_type
+ *   The type of the error ('missing' or 'moved').
+ *
+ * @see drupal_get_filename()
+ * @see _drupal_get_filename_fallback()
+ */
+function _drupal_get_filename_fallback_trigger_error($type, $name, $error_type) {
+  // Hide messages due to known bugs that will appear on a lot of sites.
+  // @todo Remove this in https://www.drupal.org/node/2383823
+  if (empty($name)) {
+    return;
+  }
+
+  // Make sure we only show any missing or moved file errors only once per
+  // request.
+  static $errors_triggered = array();
+  if (empty($errors_triggered[$type][$name][$error_type])) {
+    // Use _drupal_trigger_error_with_delayed_logging() here since these are
+    // triggered during low-level operations that cannot necessarily be
+    // interrupted by a watchdog() call.
+    if ($error_type == 'missing') {
+      _drupal_trigger_error_with_delayed_logging(format_string('The following @type is missing from the file system: %name. For information about how to fix this, see <a href="@documentation">the documentation page</a>.', array('@type' => $type, '%name' => $name, '@documentation' => 'https://www.drupal.org/node/2487215')), E_USER_WARNING);
+    }
+    elseif ($error_type == 'moved') {
+      _drupal_trigger_error_with_delayed_logging(format_string('The following @type has moved within the file system: %name. In order to fix this, clear caches or put the @type back in its original location. For more information, see <a href="@documentation">the documentation page</a>.', array('@type' => $type, '%name' => $name, '@documentation' => 'https://www.drupal.org/node/2487215')), E_USER_WARNING);
+    }
+    $errors_triggered[$type][$name][$error_type] = TRUE;
+  }
+}
+
+/**
+ * Invokes trigger_error() with logging delayed until the end of the request.
+ *
+ * This is an alternative to PHP's trigger_error() function which can be used
+ * during low-level Drupal core operations that need to avoid being interrupted
+ * by a watchdog() call.
+ *
+ * Normally, Drupal's error handler calls watchdog() in response to a
+ * trigger_error() call. However, this invokes hook_watchdog() which can run
+ * arbitrary code. If the trigger_error() happens in the middle of an
+ * operation such as a rebuild operation which should not be interrupted by
+ * arbitrary code, that could potentially break or trigger the rebuild again.
+ * This function protects against that by delaying the watchdog() call until
+ * the end of the current page request.
+ *
+ * This is an internal function which should only be called by low-level Drupal
+ * core functions. It may be removed in a future Drupal 7 release.
+ *
+ * @param string $error_msg
+ *   The error message to trigger. As with trigger_error() itself, this is
+ *   limited to 1024 bytes; additional characters beyond that will be removed.
+ * @param int $error_type
+ *   (optional) The type of error. This should be one of the E_USER family of
+ *   constants. As with trigger_error() itself, this defaults to E_USER_NOTICE
+ *   if not provided.
+ *
+ * @see _drupal_log_error()
+ */
+function _drupal_trigger_error_with_delayed_logging($error_msg, $error_type = E_USER_NOTICE) {
+  $delay_logging = &drupal_static(__FUNCTION__, FALSE);
+  $delay_logging = TRUE;
+  trigger_error($error_msg, $error_type);
+  $delay_logging = FALSE;
+}
+
+/**
+ * Writes the file scan cache to the persistent cache.
+ *
+ * This cache stores all files marked as missing or moved after a file scan
+ * to prevent unnecessary file scans in subsequent requests. This cache is
+ * cleared in system_list_reset() (i.e. after a module/theme rebuild).
+ */
+function drupal_file_scan_write_cache() {
+  // Only write to the persistent cache if requested, and if we know that any
+  // data previously in the cache was successfully loaded and merged in by
+  // _drupal_file_scan_cache().
+  $file_scans = &_drupal_file_scan_cache();
+  if (isset($file_scans['#write_cache']) && isset($file_scans['#cache_merge_done'])) {
+    unset($file_scans['#write_cache']);
+    cache_set('_drupal_file_scan_cache', $file_scans, 'cache_bootstrap');
+  }
+}
+
+/**
+ * Loads the persistent variable table.
+ *
+ * The variable table is composed of values that have been saved in the table
+ * with variable_set() as well as those explicitly specified in the
+ * configuration file.
+ */
+function variable_initialize($conf = array()) {
+  // NOTE: caching the variables improves performance by 20% when serving
+  // cached pages.
+  if ($cached = cache_get('variables', 'cache_bootstrap')) {
+    $variables = $cached->data;
+  }
+  else {
+    // Cache miss. Avoid a stampede.
+    $name = 'variable_init';
+    if (!lock_acquire($name, 1)) {
+      // Another request is building the variable cache.
+      // Wait, then re-run this function.
+      lock_wait($name);
+      return variable_initialize($conf);
+    }
+    else {
+      // Proceed with variable rebuild.
+      $variables = array_map('unserialize', db_query('SELECT name, value FROM {variable}')->fetchAllKeyed());
+      cache_set('variables', $variables, 'cache_bootstrap');
+      lock_release($name);
+    }
+  }
+
+  foreach ($conf as $name => $value) {
+    $variables[$name] = $value;
+  }
+
+  return $variables;
+}
+
+/**
+ * Returns a persistent variable.
+ *
+ * Case-sensitivity of the variable_* functions depends on the database
+ * collation used. To avoid problems, always use lower case for persistent
+ * variable names.
+ *
+ * @param $name
+ *   The name of the variable to return.
+ * @param $default
+ *   The default value to use if this variable has never been set.
+ *
+ * @return
+ *   The value of the variable. Unserialization is taken care of as necessary.
+ *
+ * @see variable_del()
+ * @see variable_set()
+ */
+function variable_get($name, $default = NULL) {
+  global $conf;
+
+  return isset($conf[$name]) ? $conf[$name] : $default;
+}
+
+/**
+ * Sets a persistent variable.
+ *
+ * Case-sensitivity of the variable_* functions depends on the database
+ * collation used. To avoid problems, always use lower case for persistent
+ * variable names.
+ *
+ * @param $name
+ *   The name of the variable to set.
+ * @param $value
+ *   The value to set. This can be any PHP data type; these functions take care
+ *   of serialization as necessary.
+ *
+ * @see variable_del()
+ * @see variable_get()
+ */
+function variable_set($name, $value) {
+  global $conf;
+
+  db_merge('variable')->key(array('name' => $name))->fields(array('value' => serialize($value)))->execute();
+
+  cache_clear_all('variables', 'cache_bootstrap');
+
+  $conf[$name] = $value;
+}
+
+/**
+ * Unsets a persistent variable.
+ *
+ * Case-sensitivity of the variable_* functions depends on the database
+ * collation used. To avoid problems, always use lower case for persistent
+ * variable names.
+ *
+ * @param $name
+ *   The name of the variable to undefine.
+ *
+ * @see variable_get()
+ * @see variable_set()
+ */
+function variable_del($name) {
+  global $conf;
+
+  db_delete('variable')
+    ->condition('name', $name)
+    ->execute();
+  cache_clear_all('variables', 'cache_bootstrap');
+
+  unset($conf[$name]);
+}
+
+/**
+ * Retrieves the current page from the cache.
+ *
+ * Note: we do not serve cached pages to authenticated users, or to anonymous
+ * users when $_SESSION is non-empty. $_SESSION may contain status messages
+ * from a form submission, the contents of a shopping cart, or other user-
+ * specific content that should not be cached and displayed to other users.
+ *
+ * @param $check_only
+ *   (optional) Set to TRUE to only return whether a previous call found a
+ *   cache entry.
+ *
+ * @return
+ *   The cache object, if the page was found in the cache, NULL otherwise.
+ */
+function drupal_page_get_cache($check_only = FALSE) {
+  global $base_root;
+  static $cache_hit = FALSE;
+
+  if ($check_only) {
+    return $cache_hit;
+  }
+
+  if (drupal_page_is_cacheable()) {
+    $cache = cache_get($base_root . request_uri(), 'cache_page');
+    if ($cache !== FALSE) {
+      $cache_hit = TRUE;
+    }
+    return $cache;
+  }
+}
+
+/**
+ * Determines the cacheability of the current page.
+ *
+ * @param $allow_caching
+ *   Set to FALSE if you want to prevent this page from being cached.
+ *
+ * @return
+ *   TRUE if the current page can be cached, FALSE otherwise.
+ */
+function drupal_page_is_cacheable($allow_caching = NULL) {
+  $allow_caching_static = &drupal_static(__FUNCTION__, TRUE);
+  if (isset($allow_caching)) {
+    $allow_caching_static = $allow_caching;
+  }
+
+  return $allow_caching_static && ($_SERVER['REQUEST_METHOD'] == 'GET' || $_SERVER['REQUEST_METHOD'] == 'HEAD')
+    && !drupal_is_cli();
+}
+
+/**
+ * Invokes a bootstrap hook in all bootstrap modules that implement it.
+ *
+ * @param $hook
+ *   The name of the bootstrap hook to invoke.
+ *
+ * @see bootstrap_hooks()
+ */
+function bootstrap_invoke_all($hook) {
+  // Bootstrap modules should have been loaded when this function is called, so
+  // we don't need to tell module_list() to reset its internal list (and we
+  // therefore leave the first parameter at its default value of FALSE). We
+  // still pass in TRUE for the second parameter, though; in case this is the
+  // first time during the bootstrap that module_list() is called, we want to
+  // make sure that its internal cache is primed with the bootstrap modules
+  // only.
+  foreach (module_list(FALSE, TRUE) as $module) {
+    drupal_load('module', $module);
+    module_invoke($module, $hook);
+  }
+}
+
+/**
+ * Includes a file with the provided type and name.
+ *
+ * This prevents including a theme, engine, module, etc., more than once.
+ *
+ * @param $type
+ *   The type of item to load (i.e. theme, theme_engine, module).
+ * @param $name
+ *   The name of the item to load.
+ *
+ * @return
+ *   TRUE if the item is loaded or has already been loaded.
+ */
+function drupal_load($type, $name) {
+  // Once a file is included this can't be reversed during a request so do not
+  // use drupal_static() here.
+  static $files = array();
+
+  if (isset($files[$type][$name])) {
+    return TRUE;
+  }
+
+  $filename = drupal_get_filename($type, $name);
+
+  if ($filename) {
+    include_once DRUPAL_ROOT . '/' . $filename;
+    $files[$type][$name] = TRUE;
+
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+/**
+ * Sets an HTTP response header for the current page.
+ *
+ * Note: When sending a Content-Type header, always include a 'charset' type,
+ * too. This is necessary to avoid security bugs (e.g. UTF-7 XSS).
+ *
+ * @param $name
+ *   The HTTP header name, or the special 'Status' header name.
+ * @param $value
+ *   The HTTP header value; if equal to FALSE, the specified header is unset.
+ *   If $name is 'Status', this is expected to be a status code followed by a
+ *   reason phrase, e.g. "404 Not Found".
+ * @param $append
+ *   Whether to append the value to an existing header or to replace it.
+ */
+function drupal_add_http_header($name, $value, $append = FALSE) {
+  // The headers as name/value pairs.
+  $headers = &drupal_static('drupal_http_headers', array());
+
+  $name_lower = strtolower($name);
+  _drupal_set_preferred_header_name($name);
+
+  if ($value === FALSE) {
+    $headers[$name_lower] = FALSE;
+  }
+  elseif (isset($headers[$name_lower]) && $append) {
+    // Multiple headers with identical names may be combined using comma (RFC
+    // 2616, section 4.2).
+    $headers[$name_lower] .= ',' . $value;
+  }
+  else {
+    $headers[$name_lower] = $value;
+  }
+  drupal_send_headers(array($name => $headers[$name_lower]), TRUE);
+}
+
+/**
+ * Gets the HTTP response headers for the current page.
+ *
+ * @param $name
+ *   An HTTP header name. If omitted, all headers are returned as name/value
+ *   pairs. If an array value is FALSE, the header has been unset.
+ *
+ * @return
+ *   A string containing the header value, or FALSE if the header has been set,
+ *   or NULL if the header has not been set.
+ */
+function drupal_get_http_header($name = NULL) {
+  $headers = &drupal_static('drupal_http_headers', array());
+  if (isset($name)) {
+    $name = strtolower($name);
+    return isset($headers[$name]) ? $headers[$name] : NULL;
+  }
+  else {
+    return $headers;
+  }
+}
+
+/**
+ * Sets the preferred name for the HTTP header.
+ *
+ * Header names are case-insensitive, but for maximum compatibility they should
+ * follow "common form" (see RFC 2617, section 4.2).
+ */
+function _drupal_set_preferred_header_name($name = NULL) {
+  static $header_names = array();
+
+  if (!isset($name)) {
+    return $header_names;
+  }
+  $header_names[strtolower($name)] = $name;
+}
+
+/**
+ * Sends the HTTP response headers that were previously set, adding defaults.
+ *
+ * Headers are set in drupal_add_http_header(). Default headers are not set
+ * if they have been replaced or unset using drupal_add_http_header().
+ *
+ * @param array $default_headers
+ *   (optional) An array of headers as name/value pairs.
+ * @param bool $only_default
+ *   (optional) If TRUE and headers have already been sent, send only the
+ *   specified headers.
+ */
+function drupal_send_headers($default_headers = array(), $only_default = FALSE) {
+  $headers_sent = &drupal_static(__FUNCTION__, FALSE);
+  $headers = drupal_get_http_header();
+  if ($only_default && $headers_sent) {
+    $headers = array();
+  }
+  $headers_sent = TRUE;
+
+  $header_names = _drupal_set_preferred_header_name();
+  foreach ($default_headers as $name => $value) {
+    $name_lower = strtolower($name);
+    if (!isset($headers[$name_lower])) {
+      $headers[$name_lower] = $value;
+      $header_names[$name_lower] = $name;
+    }
+  }
+  foreach ($headers as $name_lower => $value) {
+    if ($name_lower == 'status') {
+      header($_SERVER['SERVER_PROTOCOL'] . ' ' . $value);
+    }
+    // Skip headers that have been unset.
+    elseif ($value !== FALSE) {
+      header($header_names[$name_lower] . ': ' . $value);
+    }
+  }
+}
+
+/**
+ * Sets HTTP headers in preparation for a page response.
+ *
+ * Authenticated users are always given a 'no-cache' header, and will fetch a
+ * fresh page on every request. This prevents authenticated users from seeing
+ * locally cached pages.
+ *
+ * ETag and Last-Modified headers are not set per default for authenticated
+ * users so that browsers do not send If-Modified-Since headers from
+ * authenticated user pages. drupal_serve_page_from_cache() will set appropriate
+ * ETag and Last-Modified headers for cached pages.
+ *
+ * @see drupal_page_set_cache()
+ */
+function drupal_page_header() {
+  $headers_sent = &drupal_static(__FUNCTION__, FALSE);
+  if ($headers_sent) {
+    return TRUE;
+  }
+  $headers_sent = TRUE;
+
+  $default_headers = array(
+    'Expires' => 'Sun, 19 Nov 1978 05:00:00 GMT',
+    'Cache-Control' => 'no-cache, must-revalidate',
+    // Prevent browsers from sniffing a response and picking a MIME type
+    // different from the declared content-type, since that can lead to
+    // XSS and other vulnerabilities.
+    'X-Content-Type-Options' => 'nosniff',
+  );
+  drupal_send_headers($default_headers);
+}
+
+/**
+ * Sets HTTP headers in preparation for a cached page response.
+ *
+ * The headers allow as much as possible in proxies and browsers without any
+ * particular knowledge about the pages. Modules can override these headers
+ * using drupal_add_http_header().
+ *
+ * If the request is conditional (using If-Modified-Since and If-None-Match),
+ * and the conditions match those currently in the cache, a 304 Not Modified
+ * response is sent.
+ */
+function drupal_serve_page_from_cache(stdClass $cache) {
+  // Negotiate whether to use compression.
+  $page_compression = !empty($cache->data['page_compressed']);
+  $return_compressed = $page_compression && isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE;
+
+  // Get headers set in hook_boot(). Keys are lower-case.
+  $hook_boot_headers = drupal_get_http_header();
+
+  // Headers generated in this function, that may be replaced or unset using
+  // drupal_add_http_headers(). Keys are mixed-case.
+  $default_headers = array();
+
+  foreach ($cache->data['headers'] as $name => $value) {
+    // In the case of a 304 response, certain headers must be sent, and the
+    // remaining may not (see RFC 2616, section 10.3.5). Do not override
+    // headers set in hook_boot().
+    $name_lower = strtolower($name);
+    if (in_array($name_lower, array('content-location', 'expires', 'cache-control', 'vary')) && !isset($hook_boot_headers[$name_lower])) {
+      drupal_add_http_header($name, $value);
+      unset($cache->data['headers'][$name]);
+    }
+  }
+
+  // If the client sent a session cookie, a cached copy will only be served
+  // to that one particular client due to Vary: Cookie. Thus, do not set
+  // max-age > 0, allowing the page to be cached by external proxies, when a
+  // session cookie is present unless the Vary header has been replaced or
+  // unset in hook_boot().
+  $max_age = !isset($_COOKIE[session_name()]) || isset($hook_boot_headers['vary']) ? variable_get('page_cache_maximum_age', 0) : 0;
+  $default_headers['Cache-Control'] = 'public, max-age=' . $max_age;
+
+  // Entity tag should change if the output changes.
+  $etag = '"' . $cache->created . '-' . intval($return_compressed) . '"';
+  header('Etag: ' . $etag);
+
+  // See if the client has provided the required HTTP headers.
+  $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) : FALSE;
+  $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH']) ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) : FALSE;
+
+  if ($if_modified_since && $if_none_match
+      && $if_none_match == $etag // etag must match
+      && $if_modified_since == $cache->created) {  // if-modified-since must match
+    header($_SERVER['SERVER_PROTOCOL'] . ' 304 Not Modified');
+    drupal_send_headers($default_headers);
+    return;
+  }
+
+  // Send the remaining headers.
+  foreach ($cache->data['headers'] as $name => $value) {
+    drupal_add_http_header($name, $value);
+  }
+
+  $default_headers['Last-Modified'] = gmdate(DATE_RFC7231, $cache->created);
+
+  // HTTP/1.0 proxies does not support the Vary header, so prevent any caching
+  // by sending an Expires date in the past. HTTP/1.1 clients ignores the
+  // Expires header if a Cache-Control: max-age= directive is specified (see RFC
+  // 2616, section 14.9.3).
+  $default_headers['Expires'] = 'Sun, 19 Nov 1978 05:00:00 GMT';
+
+  drupal_send_headers($default_headers);
+
+  // Allow HTTP proxies to cache pages for anonymous users without a session
+  // cookie. The Vary header is used to indicates the set of request-header
+  // fields that fully determines whether a cache is permitted to use the
+  // response to reply to a subsequent request for a given URL without
+  // revalidation. If a Vary header has been set in hook_boot(), it is assumed
+  // that the module knows how to cache the page.
+  if (!isset($hook_boot_headers['vary']) && !variable_get('omit_vary_cookie')) {
+    header('Vary: Cookie');
+  }
+
+  if ($page_compression) {
+    header('Vary: Accept-Encoding', FALSE);
+    // If page_compression is enabled, the cache contains gzipped data.
+    if ($return_compressed) {
+      // $cache->data['body'] is already gzip'ed, so make sure
+      // zlib.output_compression does not compress it once more.
+      ini_set('zlib.output_compression', '0');
+      header('Content-Encoding: gzip');
+    }
+    else {
+      // The client does not support compression, so unzip the data in the
+      // cache. Strip the gzip header and run uncompress.
+      $cache->data['body'] = gzinflate(substr(substr($cache->data['body'], 10), 0, -8));
+    }
+  }
+
+  // Print the page.
+  print $cache->data['body'];
+}
+
+/**
+ * Defines the critical hooks that force modules to always be loaded.
+ */
+function bootstrap_hooks() {
+  return array('boot', 'exit', 'watchdog', 'language_init');
+}
+
+/**
+ * Unserializes and appends elements from a serialized string.
+ *
+ * @param $obj
+ *   The object to which the elements are appended.
+ * @param $field
+ *   The attribute of $obj whose value should be unserialized.
+ */
+function drupal_unpack($obj, $field = 'data') {
+  if ($obj->$field && $data = unserialize($obj->$field)) {
+    foreach ($data as $key => $value) {
+      if (!empty($key) && !isset($obj->$key)) {
+        $obj->$key = $value;
+      }
+    }
+  }
+  return $obj;
+}
+
+/**
+ * Translates a string to the current language or to a given language.
+ *
+ * The t() function serves two purposes. First, at run-time it translates
+ * user-visible text into the appropriate language. Second, various mechanisms
+ * that figure out what text needs to be translated work off t() -- the text
+ * inside t() calls is added to the database of strings to be translated.
+ * These strings are expected to be in English, so the first argument should
+ * always be in English. To enable a fully-translatable site, it is important
+ * that all human-readable text that will be displayed on the site or sent to
+ * a user is passed through the t() function, or a related function. See the
+ * @link http://drupal.org/node/322729 Localization API @endlink pages for
+ * more information, including recommendations on how to break up or not
+ * break up strings for translation.
+ *
+ * @section sec_translating_vars Translating Variables
+ * You should never use t() to translate variables, such as calling
+ * @code t($text); @endcode, unless the text that the variable holds has been
+ * passed through t() elsewhere (e.g., $text is one of several translated
+ * literal strings in an array). It is especially important never to call
+ * @code t($user_text); @endcode, where $user_text is some text that a user
+ * entered - doing that can lead to cross-site scripting and other security
+ * problems. However, you can use variable substitution in your string, to put
+ * variable text such as user names or link URLs into translated text. Variable
+ * substitution looks like this:
+ * @code
+ * $text = t("@name's blog", array('@name' => format_username($account)));
+ * @endcode
+ * Basically, you can put variables like @name into your string, and t() will
+ * substitute their sanitized values at translation time. (See the
+ * Localization API pages referenced above and the documentation of
+ * format_string() for details about how to define variables in your string.)
+ * Translators can then rearrange the string as necessary for the language
+ * (e.g., in Spanish, it might be "blog de @name").
+ *
+ * @section sec_alt_funcs_install Use During Installation Phase
+ * During the Drupal installation phase, some resources used by t() wil not be
+ * available to code that needs localization. See st() and get_t() for
+ * alternatives.
+ *
+ * @section sec_context String context
+ * Matching source strings are normally only translated once, and the same
+ * translation is used everywhere that has a matching string. However, in some
+ * cases, a certain English source string needs to have multiple translations.
+ * One example of this is the string "May", which could be used as either a
+ * full month name or a 3-letter abbreviated month. In other languages where
+ * the month name for May has more than 3 letters, you would need to provide
+ * two different translations (one for the full name and one abbreviated), and
+ * the correct form would need to be chosen, depending on how "May" is being
+ * used. To facilitate this, the "May" string should be provided with two
+ * different contexts in the $options parameter when calling t(). For example:
+ * @code
+ * t('May', array(), array('context' => 'Long month name')
+ * t('May', array(), array('context' => 'Abbreviated month name')
+ * @endcode
+ * See https://localize.drupal.org/node/2109 for more information.
+ *
+ * @param $string
+ *   A string containing the English string to translate.
+ * @param $args
+ *   An associative array of replacements to make after translation. Based
+ *   on the first character of the key, the value is escaped and/or themed.
+ *   See format_string() for details.
+ * @param $options
+ *   An associative array of additional options, with the following elements:
+ *   - 'langcode' (defaults to the current language): The language code to
+ *     translate to a language other than what is used to display the page.
+ *   - 'context' (defaults to the empty context): A string giving the context
+ *     that the source string belongs to. See @ref sec_context above for more
+ *     information.
+ *
+ * @return
+ *   The translated string.
+ *
+ * @see st()
+ * @see get_t()
+ * @see format_string()
+ * @ingroup sanitization
+ */
+function t($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.
+  elseif ($options['langcode'] != 'en' && function_exists('locale')) {
+    $string = locale($string, $options['context'], $options['langcode']);
+  }
+  if (empty($args)) {
+    return $string;
+  }
+  else {
+    return format_string($string, $args);
+  }
+}
+
+/**
+ * Formats a string for HTML display by replacing variable placeholders.
+ *
+ * This function replaces variable placeholders in a string with the requested
+ * values and escapes the values so they can be safely displayed as HTML. It
+ * should be used on any unknown text that is intended to be printed to an HTML
+ * page (especially text that may have come from untrusted users, since in that
+ * case it prevents cross-site scripting and other security problems).
+ *
+ * In most cases, you should use t() rather than calling this function
+ * directly, since it will translate the text (on non-English-only sites) in
+ * addition to formatting it.
+ *
+ * @param $string
+ *   A string containing placeholders.
+ * @param $args
+ *   An associative array of replacements to make. Occurrences in $string of
+ *   any key in $args are replaced with the corresponding value, after optional
+ *   sanitization and formatting. The type of sanitization and formatting
+ *   depends on the first character of the key:
+ *   - @variable: Escaped to HTML using check_plain(). Use this as the default
+ *     choice for anything displayed on a page on the site.
+ *   - %variable: Escaped to HTML and formatted using drupal_placeholder(),
+ *     which makes it display as <em>emphasized</em> text.
+ *   - !variable: Inserted as is, with no sanitization or formatting. Only use
+ *     this for text that has already been prepared for HTML display (for
+ *     example, user-supplied text that has already been run through
+ *     check_plain() previously, or is expected to contain some limited HTML
+ *     tags and has already been run through filter_xss() previously).
+ *
+ * @see t()
+ * @ingroup sanitization
+ */
+function format_string($string, array $args = array()) {
+  // Transform arguments before inserting them.
+  foreach ($args as $key => $value) {
+    switch ($key[0]) {
+      case '@':
+        // Escaped only.
+        $args[$key] = check_plain($value);
+        break;
+
+      case '%':
+      default:
+        // Escaped and placeholder.
+        $args[$key] = drupal_placeholder($value);
+        break;
+
+      case '!':
+        // Pass-through.
+    }
+  }
+  return strtr($string, $args);
+}
+
+/**
+ * Encodes special characters in a plain-text string for display as HTML.
+ *
+ * Also validates strings as UTF-8 to prevent cross site scripting attacks on
+ * Internet Explorer 6.
+ *
+ * @param string $text
+ *   The text to be checked or processed.
+ *
+ * @return string
+ *   An HTML safe version of $text. If $text is not valid UTF-8, an empty string
+ *   is returned and, on PHP < 5.4, a warning may be issued depending on server
+ *   configuration (see @link https://bugs.php.net/bug.php?id=47494 @endlink).
+ *
+ * @see drupal_validate_utf8()
+ * @ingroup sanitization
+ */
+function check_plain($text) {
+  return htmlspecialchars($text, ENT_QUOTES, 'UTF-8');
+}
+
+/**
+ * Checks whether a string is valid UTF-8.
+ *
+ * All functions designed to filter input should use drupal_validate_utf8
+ * to ensure they operate on valid UTF-8 strings to prevent bypass of the
+ * filter.
+ *
+ * When text containing an invalid UTF-8 lead byte (0xC0 - 0xFF) is presented
+ * as UTF-8 to Internet Explorer 6, the program may misinterpret subsequent
+ * bytes. When these subsequent bytes are HTML control characters such as
+ * quotes or angle brackets, parts of the text that were deemed safe by filters
+ * end up in locations that are potentially unsafe; An onerror attribute that
+ * is outside of a tag, and thus deemed safe by a filter, can be interpreted
+ * by the browser as if it were inside the tag.
+ *
+ * The function does not return FALSE for strings containing character codes
+ * above U+10FFFF, even though these are prohibited by RFC 3629.
+ *
+ * @param $text
+ *   The text to check.
+ *
+ * @return
+ *   TRUE if the text is valid UTF-8, FALSE if not.
+ */
+function drupal_validate_utf8($text) {
+  if (strlen($text) == 0) {
+    return TRUE;
+  }
+  // With the PCRE_UTF8 modifier 'u', preg_match() fails silently on strings
+  // containing invalid UTF-8 byte sequences. It does not reject character
+  // codes above U+10FFFF (represented by 4 or more octets), though.
+  return (preg_match('/^./us', $text) == 1);
+}
+
+/**
+ * Returns the equivalent of Apache's $_SERVER['REQUEST_URI'] variable.
+ *
+ * Because $_SERVER['REQUEST_URI'] is only available on Apache, we generate an
+ * equivalent using other environment variables.
+ */
+function request_uri() {
+  if (isset($_SERVER['REQUEST_URI'])) {
+    $uri = $_SERVER['REQUEST_URI'];
+  }
+  else {
+    if (isset($_SERVER['argv'])) {
+      $uri = $_SERVER['SCRIPT_NAME'] . '?' . $_SERVER['argv'][0];
+    }
+    elseif (isset($_SERVER['QUERY_STRING'])) {
+      $uri = $_SERVER['SCRIPT_NAME'] . '?' . $_SERVER['QUERY_STRING'];
+    }
+    else {
+      $uri = $_SERVER['SCRIPT_NAME'];
+    }
+  }
+  // Prevent multiple slashes to avoid cross site requests via the Form API.
+  $uri = '/' . ltrim($uri, '/');
+
+  return $uri;
+}
+
+/**
+ * Logs an exception.
+ *
+ * This is a wrapper function for watchdog() which automatically decodes an
+ * exception.
+ *
+ * @param $type
+ *   The category to which this message belongs.
+ * @param $exception
+ *   The exception that is going to be logged.
+ * @param $message
+ *   The message to store in the log. If empty, a text that contains all useful
+ *   information about the passed-in exception is used.
+ * @param $variables
+ *   Array of variables to replace in the message on display. Defaults to the
+ *   return value of _drupal_decode_exception().
+ * @param $severity
+ *   The severity of the message, as per RFC 3164.
+ * @param $link
+ *   A link to associate with the message.
+ *
+ * @see watchdog()
+ * @see _drupal_decode_exception()
+ */
+function watchdog_exception($type, Exception $exception, $message = NULL, $variables = array(), $severity = WATCHDOG_ERROR, $link = NULL) {
+
+   // Use a default value if $message is not set.
+   if (empty($message)) {
+     // The exception message is run through check_plain() by _drupal_decode_exception().
+     $message = '%type: !message in %function (line %line of %file).';
+   }
+   // $variables must be an array so that we can add the exception information.
+   if (!is_array($variables)) {
+     $variables = array();
+   }
+
+   require_once DRUPAL_ROOT . '/includes/errors.inc';
+   $variables += _drupal_decode_exception($exception);
+   watchdog($type, $message, $variables, $severity, $link);
+}
+
+/**
+ * Logs a system message.
+ *
+ * @param $type
+ *   The category to which this message belongs. Can be any string, but the
+ *   general practice is to use the name of the module calling watchdog().
+ * @param $message
+ *   The message to store in the log. Keep $message translatable
+ *   by not concatenating dynamic values into it! Variables in the
+ *   message should be added by using placeholder strings alongside
+ *   the variables argument to declare the value of the placeholders.
+ *   See t() for documentation on how $message and $variables interact.
+ * @param $variables
+ *   Array of variables to replace in the message on display or
+ *   NULL if message is already translated or not possible to
+ *   translate.
+ * @param $severity
+ *   The severity of the message; one of the following values as defined in
+ *   @link http://www.faqs.org/rfcs/rfc3164.html RFC 3164: @endlink
+ *   - WATCHDOG_EMERGENCY: Emergency, system is unusable.
+ *   - WATCHDOG_ALERT: Alert, action must be taken immediately.
+ *   - WATCHDOG_CRITICAL: Critical conditions.
+ *   - WATCHDOG_ERROR: Error conditions.
+ *   - WATCHDOG_WARNING: Warning conditions.
+ *   - WATCHDOG_NOTICE: (default) Normal but significant conditions.
+ *   - WATCHDOG_INFO: Informational messages.
+ *   - WATCHDOG_DEBUG: Debug-level messages.
+ * @param $link
+ *   A link to associate with the message.
+ *
+ * @see watchdog_severity_levels()
+ * @see hook_watchdog()
+ */
+function watchdog($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE, $link = NULL) {
+  global $user, $base_root;
+
+  static $in_error_state = FALSE;
+
+  // It is possible that the error handling will itself trigger an error. In that case, we could
+  // end up in an infinite loop. To avoid that, we implement a simple static semaphore.
+  if (!$in_error_state && function_exists('module_implements')) {
+    $in_error_state = TRUE;
+
+    // The user object may not exist in all conditions, so 0 is substituted if needed.
+    $user_uid = isset($user->uid) ? $user->uid : 0;
+
+    // Prepare the fields to be logged
+    $log_entry = array(
+      'type'        => $type,
+      'message'     => $message,
+      'variables'   => $variables,
+      'severity'    => $severity,
+      'link'        => $link,
+      'user'        => $user,
+      'uid'         => $user_uid,
+      'request_uri' => $base_root . request_uri(),
+      'referer'     => isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '',
+      'ip'          => ip_address(),
+      // Request time isn't accurate for long processes, use time() instead.
+      'timestamp'   => time(),
+    );
+
+    // Call the logging hooks to log/process the message
+    foreach (module_implements('watchdog') as $module) {
+      module_invoke($module, 'watchdog', $log_entry);
+    }
+
+    // It is critical that the semaphore is only cleared here, in the parent
+    // watchdog() call (not outside the loop), to prevent recursive execution.
+    $in_error_state = FALSE;
+  }
+}
+
+/**
+ * Sets a message to display to the user.
+ *
+ * Messages are stored in a session variable and displayed in page.tpl.php via
+ * the $messages theme variable.
+ *
+ * Example usage:
+ * @code
+ * drupal_set_message(t('An error occurred and processing did not complete.'), 'error');
+ * @endcode
+ *
+ * @param string $message
+ *   (optional) The translated message to be displayed to the user. For
+ *   consistency with other messages, it should begin with a capital letter and
+ *   end with a period.
+ * @param string $type
+ *   (optional) The message's type. Defaults to 'status'. These values are
+ *   supported:
+ *   - 'status'
+ *   - 'warning'
+ *   - 'error'
+ * @param bool $repeat
+ *   (optional) If this is FALSE and the message is already set, then the
+ *   message won't be repeated. Defaults to TRUE.
+ *
+ * @return array|null
+ *   A multidimensional array with keys corresponding to the set message types.
+ *   The indexed array values of each contain the set messages for that type.
+ *   Or, if there are no messages set, the function returns NULL.
+ *
+ * @see drupal_get_messages()
+ * @see theme_status_messages()
+ */
+function drupal_set_message($message = NULL, $type = 'status', $repeat = TRUE) {
+  if ($message || $message === '0' || $message === 0) {
+    if (!isset($_SESSION['messages'][$type])) {
+      $_SESSION['messages'][$type] = array();
+    }
+
+    if ($repeat || !in_array($message, $_SESSION['messages'][$type])) {
+      $_SESSION['messages'][$type][] = $message;
+    }
+
+    // Mark this page as being uncacheable.
+    drupal_page_is_cacheable(FALSE);
+  }
+
+  // Messages not set when DB connection fails.
+  return isset($_SESSION['messages']) ? $_SESSION['messages'] : NULL;
+}
+
+/**
+ * Returns all messages that have been set with drupal_set_message().
+ *
+ * @param string $type
+ *   (optional) Limit the messages returned by type. Defaults to NULL, meaning
+ *   all types. These values are supported:
+ *   - NULL
+ *   - 'status'
+ *   - 'warning'
+ *   - 'error'
+ * @param bool $clear_queue
+ *   (optional) If this is TRUE, the queue will be cleared of messages of the
+ *   type specified in the $type parameter. Otherwise the queue will be left
+ *   intact. Defaults to TRUE.
+ *
+ * @return array
+ *   A multidimensional array with keys corresponding to the set message types.
+ *   The indexed array values of each contain the set messages for that type.
+ *   The messages returned are limited to the type specified in the $type
+ *   parameter. If there are no messages of the specified type, an empty array
+ *   is returned.
+ *
+ * @see drupal_set_message()
+ * @see theme_status_messages()
+ */
+function drupal_get_messages($type = NULL, $clear_queue = TRUE) {
+  if ($messages = drupal_set_message()) {
+    if ($type) {
+      if ($clear_queue) {
+        unset($_SESSION['messages'][$type]);
+      }
+      if (isset($messages[$type])) {
+        return array($type => $messages[$type]);
+      }
+    }
+    else {
+      if ($clear_queue) {
+        unset($_SESSION['messages']);
+      }
+      return $messages;
+    }
+  }
+  return array();
+}
+
+/**
+ * Gets the title of the current page.
+ *
+ * The title is displayed on the page and in the title bar.
+ *
+ * @return
+ *   The current page's title.
+ */
+function drupal_get_title() {
+  $title = drupal_set_title();
+
+  // During a bootstrap, menu.inc is not included and thus we cannot provide a title.
+  if (!isset($title) && function_exists('menu_get_active_title')) {
+    $title = check_plain(menu_get_active_title());
+  }
+
+  return $title;
+}
+
+/**
+ * Sets the title of the current page.
+ *
+ * The title is displayed on the page and in the title bar.
+ *
+ * @param $title
+ *   Optional string value to assign to the page title; or if set to NULL
+ *   (default), leaves the current title unchanged.
+ * @param $output
+ *   Optional flag - normally should be left as CHECK_PLAIN. Only set to
+ *   PASS_THROUGH if you have already removed any possibly dangerous code
+ *   from $title using a function like check_plain() or filter_xss(). With this
+ *   flag the string will be passed through unchanged.
+ *
+ * @return
+ *   The updated title of the current page.
+ */
+function drupal_set_title($title = NULL, $output = CHECK_PLAIN) {
+  $stored_title = &drupal_static(__FUNCTION__);
+
+  if (isset($title)) {
+    $stored_title = ($output == PASS_THROUGH) ? $title : check_plain($title);
+  }
+
+  return $stored_title;
+}
+
+/**
+ * Checks to see if an IP address has been blocked.
+ *
+ * Blocked IP addresses are stored in the database by default. However for
+ * performance reasons we allow an override in settings.php. This allows us
+ * to avoid querying the database at this critical stage of the bootstrap if
+ * an administrative interface for IP address blocking is not required.
+ *
+ * @param $ip
+ *   IP address to check.
+ *
+ * @return bool
+ *   TRUE if access is denied, FALSE if access is allowed.
+ */
+function drupal_is_denied($ip) {
+  // Because this function is called on every page request, we first check
+  // for an array of IP addresses in settings.php before querying the
+  // database.
+  $blocked_ips = variable_get('blocked_ips');
+  $denied = FALSE;
+  if (isset($blocked_ips) && is_array($blocked_ips)) {
+    $denied = in_array($ip, $blocked_ips);
+  }
+  // Only check if database.inc is loaded already. If
+  // $conf['page_cache_without_database'] = TRUE; is set in settings.php,
+  // then the database won't be loaded here so the IPs in the database
+  // won't be denied. However the user asked explicitly not to use the
+  // database and also in this case it's quite likely that the user relies
+  // on higher performance solutions like a firewall.
+  elseif (class_exists('Database', FALSE)) {
+    $denied = (bool)db_query("SELECT 1 FROM {blocked_ips} WHERE ip = :ip", array(':ip' => $ip))->fetchField();
+  }
+  return $denied;
+}
+
+/**
+ * Handles denied users.
+ *
+ * @param $ip
+ *   IP address to check. Prints a message and exits if access is denied.
+ */
+function drupal_block_denied($ip) {
+  // Deny access to blocked IP addresses - t() is not yet available.
+  if (drupal_is_denied($ip)) {
+    header($_SERVER['SERVER_PROTOCOL'] . ' 403 Forbidden');
+    print 'Sorry, ' . check_plain(ip_address()) . ' has been banned.';
+    exit();
+  }
+}
+
+/**
+ * Returns a URL-safe, base64 encoded string of highly randomized bytes (over the full 8-bit range).
+ *
+ * @param $byte_count
+ *   The number of random bytes to fetch and base64 encode.
+ *
+ * @return string
+ *   The base64 encoded result will have a length of up to 4 * $byte_count.
+ */
+function drupal_random_key($byte_count = 32) {
+  return drupal_base64_encode(drupal_random_bytes($byte_count));
+}
+
+/**
+ * Returns a URL-safe, base64 encoded version of the supplied string.
+ *
+ * @param $string
+ *   The string to convert to base64.
+ *
+ * @return string
+ */
+function drupal_base64_encode($string) {
+  $data = base64_encode($string);
+  // Modify the output so it's safe to use in URLs.
+  return strtr($data, array('+' => '-', '/' => '_', '=' => ''));
+}
+
+/**
+ * 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, $bytes, $has_openssl;
+
+  $missing_bytes = $count - strlen($bytes);
+
+  if ($missing_bytes > 0) {
+    // PHP versions prior 5.3.4 experienced openssl_random_pseudo_bytes()
+    // locking on Windows and rendered it unusable.
+    if (!isset($has_openssl)) {
+      $has_openssl = version_compare(PHP_VERSION, '5.3.4', '>=') && function_exists('openssl_random_pseudo_bytes');
+    }
+
+    // openssl_random_pseudo_bytes() will find entropy in a system-dependent
+    // way.
+    if ($has_openssl) {
+      $bytes .= openssl_random_pseudo_bytes($missing_bytes);
+    }
+
+    // Else, read directly from /dev/urandom, which is available on many *nix
+    // systems and is considered cryptographically secure.
+    elseif ($fh = @fopen('/dev/urandom', 'rb')) {
+      // PHP only performs buffered reads, so in reality it will always read
+      // at least 4096 bytes. Thus, it costs nothing extra to read and store
+      // that much so as to speed any additional invocations.
+      $bytes .= fread($fh, max(4096, $missing_bytes));
+      fclose($fh);
+    }
+
+    // If we couldn't get enough entropy, this simple hash-based PRNG 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 hash() prior to being rolled into $output, that the two hash()
+    // 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 $output stream, which could
+    // allow for trivial prediction of further "random" numbers.
+    if (strlen($bytes) < $count) {
+      // Initialize on the first call. The contents of $_SERVER includes a mix of
+      // user-specific and system information that varies a little with each page.
+      if (!isset($random_state)) {
+        $random_state = print_r($_SERVER, TRUE);
+        if (function_exists('getmypid')) {
+          // Further initialize with the somewhat random PHP process ID.
+          $random_state .= getmypid();
+        }
+        $bytes = '';
+      }
+
+      do {
+        $random_state = hash('sha256', microtime() . mt_rand() . $random_state);
+        $bytes .= hash('sha256', mt_rand() . $random_state, TRUE);
+      }
+      while (strlen($bytes) < $count);
+    }
+  }
+  $output = substr($bytes, 0, $count);
+  $bytes = substr($bytes, $count);
+  return $output;
+}
+
+/**
+ * Calculates a base-64 encoded, URL-safe sha-256 hmac.
+ *
+ * @param string $data
+ *   String to be validated with the hmac.
+ * @param string $key
+ *   A secret string key.
+ *
+ * @return string
+ *   A base-64 encoded sha-256 hmac, with + replaced with -, / with _ and
+ *   any = padding characters removed.
+ */
+function drupal_hmac_base64($data, $key) {
+  // Casting $data and $key to strings here is necessary to avoid empty string
+  // results of the hash function if they are not scalar values. As this
+  // function is used in security-critical contexts like token validation it is
+  // important that it never returns an empty string.
+  $hmac = base64_encode(hash_hmac('sha256', (string) $data, (string) $key, TRUE));
+  // Modify the hmac so it's safe to use in URLs.
+  return strtr($hmac, array('+' => '-', '/' => '_', '=' => ''));
+}
+
+/**
+ * Calculates a base-64 encoded, URL-safe sha-256 hash.
+ *
+ * @param $data
+ *   String to be hashed.
+ *
+ * @return
+ *   A base-64 encoded sha-256 hash, with + replaced with -, / with _ and
+ *   any = padding characters removed.
+ */
+function drupal_hash_base64($data) {
+  $hash = base64_encode(hash('sha256', $data, TRUE));
+  // Modify the hash so it's safe to use in URLs.
+  return strtr($hash, array('+' => '-', '/' => '_', '=' => ''));
+}
+
+/**
+ * Merges multiple arrays, recursively, and returns the merged array.
+ *
+ * This function is similar to PHP's array_merge_recursive() function, but it
+ * handles non-array values differently. When merging values that are not both
+ * arrays, the latter value replaces the former rather than merging with it.
+ *
+ * Example:
+ * @code
+ * $link_options_1 = array('fragment' => 'x', 'attributes' => array('title' => t('X'), 'class' => array('a', 'b')));
+ * $link_options_2 = array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('c', 'd')));
+ *
+ * // This results in array('fragment' => array('x', 'y'), 'attributes' => array('title' => array(t('X'), t('Y')), 'class' => array('a', 'b', 'c', 'd'))).
+ * $incorrect = array_merge_recursive($link_options_1, $link_options_2);
+ *
+ * // This results in array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('a', 'b', 'c', 'd'))).
+ * $correct = drupal_array_merge_deep($link_options_1, $link_options_2);
+ * @endcode
+ *
+ * @param ...
+ *   Arrays to merge.
+ *
+ * @return
+ *   The merged array.
+ *
+ * @see drupal_array_merge_deep_array()
+ */
+function drupal_array_merge_deep() {
+  $args = func_get_args();
+  return drupal_array_merge_deep_array($args);
+}
+
+/**
+ * Merges multiple arrays, recursively, and returns the merged array.
+ *
+ * This function is equivalent to drupal_array_merge_deep(), except the
+ * input arrays are passed as a single array parameter rather than a variable
+ * parameter list.
+ *
+ * The following are equivalent:
+ * - drupal_array_merge_deep($a, $b);
+ * - drupal_array_merge_deep_array(array($a, $b));
+ *
+ * The following are also equivalent:
+ * - call_user_func_array('drupal_array_merge_deep', $arrays_to_merge);
+ * - drupal_array_merge_deep_array($arrays_to_merge);
+ *
+ * @see drupal_array_merge_deep()
+ */
+function drupal_array_merge_deep_array($arrays) {
+  $result = array();
+
+  foreach ($arrays as $array) {
+    foreach ($array as $key => $value) {
+      // Renumber integer keys as array_merge_recursive() does. Note that PHP
+      // automatically converts array keys that are integer strings (e.g., '1')
+      // to integers.
+      if (is_integer($key)) {
+        $result[] = $value;
+      }
+      // Recurse when both values are arrays.
+      elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
+        $result[$key] = drupal_array_merge_deep_array(array($result[$key], $value));
+      }
+      // Otherwise, use the latter value, overriding any previous value.
+      else {
+        $result[$key] = $value;
+      }
+    }
+  }
+
+  return $result;
+}
+
+/**
+ * Generates a default anonymous $user object.
+ *
+ * @return Object - the user object.
+ */
+function drupal_anonymous_user() {
+  $user = variable_get('drupal_anonymous_user_object', new stdClass);
+  $user->uid = 0;
+  $user->hostname = ip_address();
+  $user->roles = array();
+  $user->roles[DRUPAL_ANONYMOUS_RID] = 'anonymous user';
+  $user->cache = 0;
+  return $user;
+}
+
+/**
+ * Ensures Drupal is bootstrapped to the specified phase.
+ *
+ * In order to bootstrap Drupal from another PHP script, you can use this code:
+ * @code
+ *   define('DRUPAL_ROOT', '/path/to/drupal');
+ *   require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
+ *   drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
+ * @endcode
+ *
+ * @param int $phase
+ *   A constant telling which phase to bootstrap to. When you bootstrap to a
+ *   particular phase, all earlier phases are run automatically. Possible
+ *   values:
+ *   - DRUPAL_BOOTSTRAP_CONFIGURATION: Initializes configuration.
+ *   - DRUPAL_BOOTSTRAP_PAGE_CACHE: Tries to serve a cached page.
+ *   - DRUPAL_BOOTSTRAP_DATABASE: Initializes the database layer.
+ *   - DRUPAL_BOOTSTRAP_VARIABLES: Initializes the variable system.
+ *   - DRUPAL_BOOTSTRAP_SESSION: Initializes session handling.
+ *   - DRUPAL_BOOTSTRAP_PAGE_HEADER: Sets up the page header.
+ *   - DRUPAL_BOOTSTRAP_LANGUAGE: Finds out the language of the page.
+ *   - DRUPAL_BOOTSTRAP_FULL: Fully loads Drupal. Validates and fixes input
+ *     data.
+ * @param boolean $new_phase
+ *   A boolean, set to FALSE if calling drupal_bootstrap from inside a
+ *   function called from drupal_bootstrap (recursion).
+ *
+ * @return int
+ *   The most recently completed phase.
+ */
+function drupal_bootstrap($phase = NULL, $new_phase = TRUE) {
+  // Not drupal_static(), because does not depend on any run-time information.
+  static $phases = array(
+    DRUPAL_BOOTSTRAP_CONFIGURATION,
+    DRUPAL_BOOTSTRAP_PAGE_CACHE,
+    DRUPAL_BOOTSTRAP_DATABASE,
+    DRUPAL_BOOTSTRAP_VARIABLES,
+    DRUPAL_BOOTSTRAP_SESSION,
+    DRUPAL_BOOTSTRAP_PAGE_HEADER,
+    DRUPAL_BOOTSTRAP_LANGUAGE,
+    DRUPAL_BOOTSTRAP_FULL,
+  );
+  // Not drupal_static(), because the only legitimate API to control this is to
+  // call drupal_bootstrap() with a new phase parameter.
+  static $final_phase;
+  // Not drupal_static(), because it's impossible to roll back to an earlier
+  // bootstrap state.
+  static $stored_phase = -1;
+
+  if (isset($phase)) {
+    // When not recursing, store the phase name so it's not forgotten while
+    // recursing but take care of not going backwards.
+    if ($new_phase && $phase >= $stored_phase) {
+      $final_phase = $phase;
+    }
+
+    // Call a phase if it has not been called before and is below the requested
+    // phase.
+    while ($phases && $phase > $stored_phase && $final_phase > $stored_phase) {
+      $current_phase = array_shift($phases);
+
+      // This function is re-entrant. Only update the completed phase when the
+      // current call actually resulted in a progress in the bootstrap process.
+      if ($current_phase > $stored_phase) {
+        $stored_phase = $current_phase;
+      }
+
+      switch ($current_phase) {
+        case DRUPAL_BOOTSTRAP_CONFIGURATION:
+          _drupal_bootstrap_configuration();
+          break;
+
+        case DRUPAL_BOOTSTRAP_PAGE_CACHE:
+          _drupal_bootstrap_page_cache();
+          break;
+
+        case DRUPAL_BOOTSTRAP_DATABASE:
+          _drupal_bootstrap_database();
+          break;
+
+        case DRUPAL_BOOTSTRAP_VARIABLES:
+          _drupal_bootstrap_variables();
+          break;
+
+        case DRUPAL_BOOTSTRAP_SESSION:
+          require_once DRUPAL_ROOT . '/' . variable_get('session_inc', 'includes/session.inc');
+          drupal_session_initialize();
+          break;
+
+        case DRUPAL_BOOTSTRAP_PAGE_HEADER:
+          _drupal_bootstrap_page_header();
+          break;
+
+        case DRUPAL_BOOTSTRAP_LANGUAGE:
+          drupal_language_initialize();
+          break;
+
+        case DRUPAL_BOOTSTRAP_FULL:
+          require_once DRUPAL_ROOT . '/includes/common.inc';
+          _drupal_bootstrap_full();
+          break;
+      }
+    }
+  }
+  return $stored_phase;
+}
+
+/**
+ * Returns the time zone of the current user.
+ */
+function drupal_get_user_timezone() {
+  global $user;
+  if (variable_get('configurable_timezones', 1) && $user->uid && $user->timezone) {
+    return $user->timezone;
+  }
+  else {
+    // Ignore PHP strict notice if time zone has not yet been set in the php.ini
+    // configuration.
+    return variable_get('date_default_timezone', @date_default_timezone_get());
+  }
+}
+
+/**
+ * Gets a salt useful for hardening against SQL injection.
+ *
+ * @return
+ *   A salt based on information in settings.php, not in the database.
+ */
+function drupal_get_hash_salt() {
+  global $drupal_hash_salt, $databases;
+  // If the $drupal_hash_salt variable is empty, a hash of the serialized
+  // database credentials is used as a fallback salt.
+  return empty($drupal_hash_salt) ? hash('sha256', serialize($databases)) : $drupal_hash_salt;
+}
+
+/**
+ * Provides custom PHP error handling.
+ *
+ * @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, $context) {
+  require_once DRUPAL_ROOT . '/includes/errors.inc';
+  _drupal_error_handler_real($error_level, $message, $filename, $line, $context);
+}
+
+/**
+ * Provides custom PHP exception handling.
+ *
+ * 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) {
+  require_once DRUPAL_ROOT . '/includes/errors.inc';
+
+  try {
+    // Log the message to the watchdog and return an error page to the user.
+    _drupal_log_error(_drupal_decode_exception($exception), TRUE);
+  }
+  catch (Exception $exception2) {
+    // Another uncaught exception was thrown while handling the first one.
+    // If we are displaying errors, then do so with no possibility of a further uncaught exception being thrown.
+    if (error_displayable()) {
+      print '<h1>Additional uncaught exception thrown while handling exception.</h1>';
+      print '<h2>Original</h2><p>' . _drupal_render_exception_safe($exception) . '</p>';
+      print '<h2>Additional</h2><p>' . _drupal_render_exception_safe($exception2) . '</p><hr />';
+    }
+  }
+}
+
+/**
+ * Sets up the script environment and loads settings.php.
+ */
+function _drupal_bootstrap_configuration() {
+  // Set the Drupal custom error handler.
+  set_error_handler('_drupal_error_handler');
+  set_exception_handler('_drupal_exception_handler');
+
+  drupal_environment_initialize();
+  // Start a page timer:
+  timer_start('page');
+  // Initialize the configuration, including variables from settings.php.
+  drupal_settings_initialize();
+}
+
+/**
+ * Attempts to serve a page from the cache.
+ */
+function _drupal_bootstrap_page_cache() {
+  global $user;
+
+  // Allow specifying special cache handlers in settings.php, like
+  // using memcached or files for storing cache information.
+  require_once DRUPAL_ROOT . '/includes/cache.inc';
+  foreach (variable_get('cache_backends', array()) as $include) {
+    require_once DRUPAL_ROOT . '/' . $include;
+  }
+  // Check for a cache mode force from settings.php.
+  if (variable_get('page_cache_without_database')) {
+    $cache_enabled = TRUE;
+  }
+  else {
+    drupal_bootstrap(DRUPAL_BOOTSTRAP_VARIABLES, FALSE);
+    $cache_enabled = variable_get('cache');
+  }
+  drupal_block_denied(ip_address());
+  // If there is no session cookie and cache is enabled (or forced), try
+  // to serve a cached page.
+  if (!isset($_COOKIE[session_name()]) && $cache_enabled) {
+    // Make sure there is a user object because its timestamp will be
+    // checked, hook_boot might check for anonymous user etc.
+    $user = drupal_anonymous_user();
+    // Get the page from the cache.
+    $cache = drupal_page_get_cache();
+    // If there is a cached page, display it.
+    if (is_object($cache)) {
+      header('X-Drupal-Cache: HIT');
+      // Restore the metadata cached with the page.
+      $_GET['q'] = $cache->data['path'];
+      drupal_set_title($cache->data['title'], PASS_THROUGH);
+      date_default_timezone_set(drupal_get_user_timezone());
+      // If the skipping of the bootstrap hooks is not enforced, call
+      // hook_boot.
+      if (variable_get('page_cache_invoke_hooks', TRUE)) {
+        bootstrap_invoke_all('boot');
+      }
+      drupal_serve_page_from_cache($cache);
+      // If the skipping of the bootstrap hooks is not enforced, call
+      // hook_exit.
+      if (variable_get('page_cache_invoke_hooks', TRUE)) {
+        bootstrap_invoke_all('exit');
+      }
+      // We are done.
+      exit;
+    }
+    else {
+      header('X-Drupal-Cache: MISS');
+    }
+  }
+}
+
+/**
+ * Initializes the database system and registers autoload functions.
+ */
+function _drupal_bootstrap_database() {
+  // Redirect the user to the installation script if Drupal has not been
+  // installed yet (i.e., if no $databases array has been defined in the
+  // settings.php file) and we are not already installing.
+  if (empty($GLOBALS['databases']) && !drupal_installation_attempted()) {
+    include_once DRUPAL_ROOT . '/includes/install.inc';
+    install_goto('install.php');
+  }
+
+  // The user agent header is used to pass a database prefix in the request when
+  // running tests. However, for security reasons, it is imperative that we
+  // validate we ourselves made the request.
+  if ($test_prefix = drupal_valid_test_ua()) {
+    // Set the test run id for use in other parts of Drupal.
+    $test_info = &$GLOBALS['drupal_test_info'];
+    $test_info['test_run_id'] = $test_prefix;
+    $test_info['in_child_site'] = TRUE;
+
+    foreach ($GLOBALS['databases']['default'] as &$value) {
+      // Extract the current default database prefix.
+      if (!isset($value['prefix'])) {
+        $current_prefix = '';
+      }
+      elseif (is_array($value['prefix'])) {
+        $current_prefix = $value['prefix']['default'];
+      }
+      else {
+        $current_prefix = $value['prefix'];
+      }
+
+      // Remove the current database prefix and replace it by our own.
+      $value['prefix'] = array(
+        'default' => $current_prefix . $test_prefix,
+      );
+    }
+  }
+
+  // Initialize the database system. Note that the connection
+  // won't be initialized until it is actually requested.
+  require_once DRUPAL_ROOT . '/includes/database/database.inc';
+
+  // Register autoload functions so that we can access classes and interfaces.
+  // The database autoload routine comes first so that we can load the database
+  // system without hitting the database. That is especially important during
+  // the install or upgrade process.
+  spl_autoload_register('drupal_autoload_class');
+  spl_autoload_register('drupal_autoload_interface');
+  if (version_compare(PHP_VERSION, '5.4') >= 0) {
+    spl_autoload_register('drupal_autoload_trait');
+  }
+}
+
+/**
+ * Loads system variables and all enabled bootstrap modules.
+ */
+function _drupal_bootstrap_variables() {
+  global $conf;
+
+  // Initialize the lock system.
+  require_once DRUPAL_ROOT . '/' . variable_get('lock_inc', 'includes/lock.inc');
+  lock_initialize();
+
+  // Load variables from the database, but do not overwrite variables set in settings.php.
+  $conf = variable_initialize(isset($conf) ? $conf : array());
+  // Load bootstrap modules.
+  require_once DRUPAL_ROOT . '/includes/module.inc';
+  module_load_all(TRUE);
+
+  // Sanitize the destination parameter (which is often used for redirects) to
+  // prevent open redirect attacks leading to other domains. Sanitize both
+  // $_GET['destination'] and $_REQUEST['destination'] to protect code that
+  // relies on either, but do not sanitize $_POST to avoid interfering with
+  // unrelated form submissions. The sanitization happens here because
+  // url_is_external() requires the variable system to be available.
+  if (isset($_GET['destination']) || isset($_REQUEST['destination'])) {
+    require_once DRUPAL_ROOT . '/includes/common.inc';
+    // If the destination is an external URL, remove it.
+    if (isset($_GET['destination']) && url_is_external($_GET['destination'])) {
+      unset($_GET['destination']);
+      unset($_REQUEST['destination']);
+    }
+    // If there's still something in $_REQUEST['destination'] that didn't come
+    // from $_GET, check it too.
+    if (isset($_REQUEST['destination']) && (!isset($_GET['destination']) || $_REQUEST['destination'] != $_GET['destination']) && url_is_external($_REQUEST['destination'])) {
+      unset($_REQUEST['destination']);
+    }
+  }
+}
+
+/**
+ * Invokes hook_boot(), initializes locking system, and sends HTTP headers.
+ */
+function _drupal_bootstrap_page_header() {
+  bootstrap_invoke_all('boot');
+
+  if (!drupal_is_cli()) {
+    ob_start();
+    drupal_page_header();
+  }
+}
+
+/**
+ * Returns the current bootstrap phase for this Drupal process.
+ *
+ * The current phase is the one most recently completed by drupal_bootstrap().
+ *
+ * @see drupal_bootstrap()
+ */
+function drupal_get_bootstrap_phase() {
+  return drupal_bootstrap(NULL, FALSE);
+}
+
+/**
+ * Returns the test prefix if this is an internal request from SimpleTest.
+ *
+ * @return
+ *   Either the simpletest prefix (the string "simpletest" followed by any
+ *   number of digits) or FALSE if the user agent does not contain a valid
+ *   HMAC and timestamp.
+ */
+function drupal_valid_test_ua() {
+  // No reason to reset this.
+  static $test_prefix;
+
+  if (isset($test_prefix)) {
+    return $test_prefix;
+  }
+
+  if (isset($_SERVER['HTTP_USER_AGENT']) && preg_match("/^(simpletest\d+);(.+);(.+);(.+)$/", $_SERVER['HTTP_USER_AGENT'], $matches)) {
+    list(, $prefix, $time, $salt, $hmac) = $matches;
+    $check_string =  $prefix . ';' . $time . ';' . $salt;
+    // We use the salt from settings.php to make the HMAC key, since
+    // the database is not yet initialized and we can't access any Drupal variables.
+    // The file properties add more entropy not easily accessible to others.
+    $key = drupal_get_hash_salt() . filectime(__FILE__) . fileinode(__FILE__);
+    $time_diff = REQUEST_TIME - $time;
+    // Since we are making a local request a 5 second time window is allowed,
+    // and the HMAC must match.
+    if ($time_diff >= 0 && $time_diff <= 5 && $hmac == drupal_hmac_base64($check_string, $key)) {
+      $test_prefix = $prefix;
+      return $test_prefix;
+    }
+  }
+
+  $test_prefix = FALSE;
+  return $test_prefix;
+}
+
+/**
+ * Generates a user agent string with a HMAC and timestamp for simpletest.
+ */
+function drupal_generate_test_ua($prefix) {
+  static $key;
+
+  if (!isset($key)) {
+    // We use the salt from settings.php to make the HMAC key, since
+    // the database is not yet initialized and we can't access any Drupal variables.
+    // The file properties add more entropy not easily accessible to others.
+    $key = drupal_get_hash_salt() . filectime(__FILE__) . fileinode(__FILE__);
+  }
+  // Generate a moderately secure HMAC based on the database credentials.
+  $salt = uniqid('', TRUE);
+  $check_string = $prefix . ';' . time() . ';' . $salt;
+  return $check_string . ';' . drupal_hmac_base64($check_string, $key);
+}
+
+/**
+ * Enables use of the theme system without requiring database access.
+ *
+ * Loads and initializes the theme system for site installs, updates and when
+ * the site is in maintenance mode. This also applies when the database fails.
+ *
+ * @see _drupal_maintenance_theme()
+ */
+function drupal_maintenance_theme() {
+  require_once DRUPAL_ROOT . '/includes/theme.maintenance.inc';
+  _drupal_maintenance_theme();
+}
+
+/**
+ * Returns a simple 404 Not Found page.
+ *
+ * If fast 404 pages are enabled, and this is a matching page then print a
+ * simple 404 page and exit.
+ *
+ * This function is called from drupal_deliver_html_page() at the time when a
+ * a normal 404 page is generated, but it can also optionally be called directly
+ * from settings.php to prevent a Drupal bootstrap on these pages. See
+ * documentation in settings.php for the benefits and drawbacks of using this.
+ *
+ * Paths to dynamically-generated content, such as image styles, should also be
+ * accounted for in this function.
+ */
+function drupal_fast_404() {
+  $exclude_paths = variable_get('404_fast_paths_exclude', FALSE);
+  if ($exclude_paths && !preg_match($exclude_paths, $_GET['q'])) {
+    $fast_paths = variable_get('404_fast_paths', FALSE);
+    if ($fast_paths && preg_match($fast_paths, $_GET['q'])) {
+      drupal_add_http_header('Status', '404 Not Found');
+      $fast_404_html = variable_get('404_fast_html', '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>404 Not Found</title></head><body><h1>Not Found</h1><p>The requested URL "@path" was not found on this server.</p></body></html>');
+      // Replace @path in the variable with the page path.
+      print strtr($fast_404_html, array('@path' => check_plain(request_uri())));
+      exit;
+    }
+  }
+}
+
+/**
+ * Returns TRUE if a Drupal installation is currently being attempted.
+ */
+function drupal_installation_attempted() {
+  return defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'install';
+}
+
+/**
+ * Returns the name of the proper localization function.
+ *
+ * get_t() exists to support localization for code that might run during
+ * the installation phase, when some elements of the system might not have
+ * loaded.
+ *
+ * This would include implementations of hook_install(), which could run
+ * during the Drupal installation phase, and might also be run during
+ * non-installation time, such as while installing the module from the
+ * module administration page.
+ *
+ * Example usage:
+ * @code
+ *   $t = get_t();
+ *   $translated = $t('translate this');
+ * @endcode
+ *
+ * Use t() if your code will never run during the Drupal installation phase.
+ * Use st() if your code will only run during installation and never any other
+ * time. Use get_t() if your code could run in either circumstance.
+ *
+ * @see t()
+ * @see st()
+ * @ingroup sanitization
+ */
+function get_t() {
+  static $t;
+  // This is not converted to drupal_static because there is no point in
+  // resetting this as it can not change in the course of a request.
+  if (!isset($t)) {
+    $t = drupal_installation_attempted() ? 'st' : 't';
+  }
+  return $t;
+}
+
+/**
+ * Initializes all the defined language types.
+ */
+function drupal_language_initialize() {
+  $types = language_types();
+
+  // Ensure the language is correctly returned, even without multilanguage
+  // support. Also make sure we have a $language fallback, in case a language
+  // negotiation callback needs to do a full bootstrap.
+  // Useful for eg. XML/HTML 'lang' attributes.
+  $default = language_default();
+  foreach ($types as $type) {
+    $GLOBALS[$type] = $default;
+  }
+  if (drupal_multilingual()) {
+    include_once DRUPAL_ROOT . '/includes/language.inc';
+    foreach ($types as $type) {
+      $GLOBALS[$type] = language_initialize($type);
+    }
+    // Allow modules to react on language system initialization in multilingual
+    // environments.
+    bootstrap_invoke_all('language_init');
+  }
+}
+
+/**
+ * Returns a list of the built-in language types.
+ *
+ * @return
+ *   An array of key-values pairs where the key is the language type and the
+ *   value is its configurability.
+ */
+function drupal_language_types() {
+  return array(
+    LANGUAGE_TYPE_INTERFACE => TRUE,
+    LANGUAGE_TYPE_CONTENT => FALSE,
+    LANGUAGE_TYPE_URL => FALSE,
+  );
+}
+
+/**
+ * Returns TRUE if there is more than one language enabled.
+ *
+ * @return
+ *   TRUE if more than one language is enabled.
+ */
+function drupal_multilingual() {
+  // The "language_count" variable stores the number of enabled languages to
+  // avoid unnecessarily querying the database when building the list of
+  // enabled languages on monolingual sites.
+  return variable_get('language_count', 1) > 1;
+}
+
+/**
+ * Returns an array of the available language types.
+ *
+ * @return
+ *   An array of all language types where the keys of each are the language type
+ *   name and its value is its configurability (TRUE/FALSE).
+ */
+function language_types() {
+  return array_keys(variable_get('language_types', drupal_language_types()));
+}
+
+/**
+ * Returns a list of installed languages, indexed by the specified key.
+ *
+ * @param $field
+ *   (optional) The field to index the list with.
+ *
+ * @return
+ *   An associative array, keyed on the values of $field.
+ *   - If $field is 'weight' or 'enabled', the array is nested, with the outer
+ *     array's values each being associative arrays with language codes as
+ *     keys and language objects as values.
+ *   - For all other values of $field, the array is only one level deep, and
+ *     the array's values are language objects.
+ */
+function language_list($field = 'language') {
+  $languages = &drupal_static(__FUNCTION__);
+  // Init language list
+  if (!isset($languages)) {
+    if (drupal_multilingual() || module_exists('locale')) {
+      $languages['language'] = db_query('SELECT * FROM {languages} ORDER BY weight ASC, name ASC')->fetchAllAssoc('language');
+      // Users cannot uninstall the native English language. However, we allow
+      // it to be hidden from the installed languages. Therefore, at least one
+      // other language must be enabled then.
+      if (!$languages['language']['en']->enabled && !variable_get('language_native_enabled', TRUE)) {
+        unset($languages['language']['en']);
+      }
+    }
+    else {
+      // No locale module, so use the default language only.
+      $default = language_default();
+      $languages['language'][$default->language] = $default;
+    }
+  }
+
+  // Return the array indexed by the right field
+  if (!isset($languages[$field])) {
+    $languages[$field] = array();
+    foreach ($languages['language'] as $lang) {
+      // Some values should be collected into an array
+      if (in_array($field, array('enabled', 'weight'))) {
+        $languages[$field][$lang->$field][$lang->language] = $lang;
+      }
+      else {
+        $languages[$field][$lang->$field] = $lang;
+      }
+    }
+  }
+  return $languages[$field];
+}
+
+/**
+ * Returns the default language, as an object, or one of its properties.
+ *
+ * @param $property
+ *   (optional) The property of the language object to return.
+ *
+ * @return
+ *   Either the language object for the default language used on the site,
+ *   or the property of that object named in the $property parameter.
+ */
+function language_default($property = NULL) {
+  $language = variable_get('language_default', (object) array('language' => 'en', 'name' => 'English', 'native' => 'English', 'direction' => 0, 'enabled' => 1, 'plurals' => 0, 'formula' => '', 'domain' => '', 'prefix' => '', 'weight' => 0, 'javascript' => ''));
+  return $property ? $language->$property : $language;
+}
+
+/**
+ * Returns the requested URL path of the page being viewed.
+ *
+ * Examples:
+ * - http://example.com/node/306 returns "node/306".
+ * - http://example.com/drupalfolder/node/306 returns "node/306" while
+ *   base_path() returns "/drupalfolder/".
+ * - http://example.com/path/alias (which is a path alias for node/306) returns
+ *   "path/alias" as opposed to the internal path.
+ * - http://example.com/index.php returns an empty string (meaning: front page).
+ * - http://example.com/index.php?page=1 returns an empty string.
+ *
+ * @return
+ *   The requested Drupal URL path.
+ *
+ * @see current_path()
+ */
+function request_path() {
+  static $path;
+
+  if (isset($path)) {
+    return $path;
+  }
+
+  if (isset($_GET['q']) && is_string($_GET['q'])) {
+    // This is a request with a ?q=foo/bar query string. $_GET['q'] is
+    // overwritten in drupal_path_initialize(), but request_path() is called
+    // very early in the bootstrap process, so the original value is saved in
+    // $path and returned in later calls.
+    $path = $_GET['q'];
+  }
+  elseif (isset($_SERVER['REQUEST_URI'])) {
+    // This request is either a clean URL, or 'index.php', or nonsense.
+    // Extract the path from REQUEST_URI.
+    $request_path = strtok($_SERVER['REQUEST_URI'], '?');
+    $base_path_len = strlen(rtrim(dirname($_SERVER['SCRIPT_NAME']), '\/'));
+    // Unescape and strip $base_path prefix, leaving q without a leading slash.
+    $path = substr(urldecode($request_path), $base_path_len + 1);
+    // If the path equals the script filename, either because 'index.php' was
+    // explicitly provided in the URL, or because the server added it to
+    // $_SERVER['REQUEST_URI'] even when it wasn't provided in the URL (some
+    // versions of Microsoft IIS do this), the front page should be served.
+    if ($path == basename($_SERVER['PHP_SELF'])) {
+      $path = '';
+    }
+  }
+  else {
+    // This is the front page.
+    $path = '';
+  }
+
+  // Under certain conditions Apache's RewriteRule directive prepends the value
+  // assigned to $_GET['q'] with a slash. Moreover we can always have a trailing
+  // slash in place, hence we need to normalize $_GET['q'].
+  $path = trim($path, '/');
+
+  return $path;
+}
+
+/**
+ * Returns a component of the current Drupal path.
+ *
+ * When viewing a page at the path "admin/structure/types", for example, arg(0)
+ * returns "admin", arg(1) returns "structure", and arg(2) returns "types".
+ *
+ * Avoid use of this function where possible, as resulting code is hard to
+ * read. In menu callback functions, attempt to use named arguments. See the
+ * explanation in menu.inc for how to construct callbacks that take arguments.
+ * When attempting to use this function to load an element from the current
+ * path, e.g. loading the node on a node page, use menu_get_object() instead.
+ *
+ * @param $index
+ *   The index of the component, where each component is separated by a '/'
+ *   (forward-slash), and where the first component has an index of 0 (zero).
+ * @param $path
+ *   A path to break into components. Defaults to the path of the current page.
+ *
+ * @return
+ *   The component specified by $index, or NULL if the specified component was
+ *   not found. If called without arguments, it returns an array containing all
+ *   the components of the current path.
+ */
+function arg($index = NULL, $path = NULL) {
+  // Even though $arguments doesn't need to be resettable for any functional
+  // reasons (the result of explode() does not depend on any run-time
+  // information), it should be resettable anyway in case a module needs to
+  // free up the memory used by it.
+  // Use the advanced drupal_static() pattern, since this is called very often.
+  static $drupal_static_fast;
+  if (!isset($drupal_static_fast)) {
+    $drupal_static_fast['arguments'] = &drupal_static(__FUNCTION__);
+  }
+  $arguments = &$drupal_static_fast['arguments'];
+
+  if (!isset($path)) {
+    $path = $_GET['q'];
+  }
+  if (!isset($arguments[$path])) {
+    $arguments[$path] = explode('/', $path);
+  }
+  if (!isset($index)) {
+    return $arguments[$path];
+  }
+  if (isset($arguments[$path][$index])) {
+    return $arguments[$path][$index];
+  }
+}
+
+/**
+ * Returns the IP address of the client machine.
+ *
+ * If Drupal is behind a reverse proxy, we use the X-Forwarded-For header
+ * instead of $_SERVER['REMOTE_ADDR'], which would be the IP address of
+ * the proxy server, and not the client's. The actual header name can be
+ * configured by the reverse_proxy_header variable.
+ *
+ * @return
+ *   IP address of client machine, adjusted for reverse proxy and/or cluster
+ *   environments.
+ */
+function ip_address() {
+  $ip_address = &drupal_static(__FUNCTION__);
+
+  if (!isset($ip_address)) {
+    $ip_address = $_SERVER['REMOTE_ADDR'];
+
+    if (variable_get('reverse_proxy', 0)) {
+      $reverse_proxy_header = variable_get('reverse_proxy_header', 'HTTP_X_FORWARDED_FOR');
+      if (!empty($_SERVER[$reverse_proxy_header])) {
+        // If an array of known reverse proxy IPs is provided, then trust
+        // the XFF header if request really comes from one of them.
+        $reverse_proxy_addresses = variable_get('reverse_proxy_addresses', array());
+
+        // Turn XFF header into an array.
+        $forwarded = explode(',', $_SERVER[$reverse_proxy_header]);
+
+        // Trim the forwarded IPs; they may have been delimited by commas and spaces.
+        $forwarded = array_map('trim', $forwarded);
+
+        // Tack direct client IP onto end of forwarded array.
+        $forwarded[] = $ip_address;
+
+        // Eliminate all trusted IPs.
+        $untrusted = array_diff($forwarded, $reverse_proxy_addresses);
+
+        if (!empty($untrusted)) {
+          // The right-most IP is the most specific we can trust.
+          $ip_address = array_pop($untrusted);
+        }
+        else {
+          // All IP addresses in the forwarded array are configured proxy IPs
+          // (and thus trusted). We take the leftmost IP.
+          $ip_address = array_shift($forwarded);
+        }
+      }
+    }
+  }
+
+  return $ip_address;
+}
+
+/**
+ * @addtogroup schemaapi
+ * @{
+ */
+
+/**
+ * Gets the schema definition of a table, or the whole database schema.
+ *
+ * The returned schema will include any modifications made by any
+ * module that implements hook_schema_alter(). To get the schema without
+ * modifications, use drupal_get_schema_unprocessed().
+ *
+ *
+ * @param $table
+ *   The name of the table. If not given, the schema of all tables is returned.
+ * @param $rebuild
+ *   If true, the schema will be rebuilt instead of retrieved from the cache.
+ */
+function drupal_get_schema($table = NULL, $rebuild = FALSE) {
+  static $schema;
+
+  if ($rebuild || !isset($table)) {
+    $schema = drupal_get_complete_schema($rebuild);
+  }
+  elseif (!isset($schema)) {
+    $schema = new SchemaCache();
+  }
+
+  if (!isset($table)) {
+    return $schema;
+  }
+  if (isset($schema[$table])) {
+    return $schema[$table];
+  }
+  else {
+    return FALSE;
+  }
+}
+
+/**
+ * Extends DrupalCacheArray to allow for dynamic building of the schema cache.
+ */
+class SchemaCache extends DrupalCacheArray {
+
+  /**
+   * Constructs a SchemaCache object.
+   */
+  public function __construct() {
+    // Cache by request method.
+    parent::__construct('schema:runtime:' . ($_SERVER['REQUEST_METHOD'] == 'GET'), 'cache');
+  }
+
+  /**
+   * Overrides DrupalCacheArray::resolveCacheMiss().
+   */
+  protected function resolveCacheMiss($offset) {
+    $complete_schema = drupal_get_complete_schema();
+    $value = isset($complete_schema[$offset]) ? $complete_schema[$offset] :  NULL;
+    $this->storage[$offset] = $value;
+    $this->persist($offset);
+    return $value;
+  }
+}
+
+/**
+ * Gets the whole database schema.
+ *
+ * The returned schema will include any modifications made by any
+ * module that implements hook_schema_alter().
+ *
+ * @param $rebuild
+ *   If true, the schema will be rebuilt instead of retrieved from the cache.
+ */
+function drupal_get_complete_schema($rebuild = FALSE) {
+  static $schema = array();
+
+  if (empty($schema) || $rebuild) {
+    // Try to load the schema from cache.
+    if (!$rebuild && $cached = cache_get('schema')) {
+      $schema = $cached->data;
+    }
+    // Otherwise, rebuild the schema cache.
+    else {
+      $schema = array();
+      // Load the .install files to get hook_schema.
+      // On some databases this function may be called before bootstrap has
+      // been completed, so we force the functions we need to load just in case.
+      if (function_exists('module_load_all_includes')) {
+        // This function can be called very early in the bootstrap process, so
+        // we force the module_list() cache to be refreshed to ensure that it
+        // contains the complete list of modules before we go on to call
+        // module_load_all_includes().
+        module_list(TRUE);
+        module_load_all_includes('install');
+      }
+
+      require_once DRUPAL_ROOT . '/includes/common.inc';
+      // Invoke hook_schema for all modules.
+      foreach (module_implements('schema') as $module) {
+        // Cast the result of hook_schema() to an array, as a NULL return value
+        // would cause array_merge() to set the $schema variable to NULL as well.
+        // That would break modules which use $schema further down the line.
+        $current = (array) module_invoke($module, 'schema');
+        // Set 'module' and 'name' keys for each table, and remove descriptions,
+        // as they needlessly slow down cache_get() for every single request.
+        _drupal_schema_initialize($current, $module);
+        $schema = array_merge($schema, $current);
+      }
+
+      drupal_alter('schema', $schema);
+      // If the schema is empty, avoid saving it: some database engines require
+      // the schema to perform queries, and this could lead to infinite loops.
+      if (!empty($schema) && (drupal_get_bootstrap_phase() == DRUPAL_BOOTSTRAP_FULL)) {
+        cache_set('schema', $schema);
+      }
+      if ($rebuild) {
+        cache_clear_all('schema:', 'cache', TRUE);
+      }
+    }
+  }
+
+  return $schema;
+}
+
+/**
+ * @} End of "addtogroup schemaapi".
+ */
+
+
+/**
+ * @addtogroup registry
+ * @{
+ */
+
+/**
+ * Confirms that an interface is available.
+ *
+ * This function is rarely called directly. Instead, it is registered as an
+ * spl_autoload()  handler, and PHP calls it for us when necessary.
+ *
+ * @param $interface
+ *   The name of the interface to check or load.
+ *
+ * @return
+ *   TRUE if the interface is currently available, FALSE otherwise.
+ */
+function drupal_autoload_interface($interface) {
+  return _registry_check_code('interface', $interface);
+}
+
+/**
+ * Confirms that a class is available.
+ *
+ * This function is rarely called directly. Instead, it is registered as an
+ * spl_autoload()  handler, and PHP calls it for us when necessary.
+ *
+ * @param $class
+ *   The name of the class to check or load.
+ *
+ * @return
+ *   TRUE if the class is currently available, FALSE otherwise.
+ */
+function drupal_autoload_class($class) {
+  return _registry_check_code('class', $class);
+}
+
+/**
+ * Confirms that a trait is available.
+ *
+ * This function is rarely called directly. Instead, it is registered as an
+ * spl_autoload() handler, and PHP calls it for us when necessary.
+ *
+ * @param string $trait
+ *   The name of the trait to check or load.
+ *
+ * @return bool
+ *   TRUE if the trait is currently available, FALSE otherwise.
+ */
+function drupal_autoload_trait($trait) {
+  return _registry_check_code('trait', $trait);
+}
+
+/**
+ * Checks for a resource in the registry.
+ *
+ * @param $type
+ *   The type of resource we are looking up, or one of the constants
+ *   REGISTRY_RESET_LOOKUP_CACHE or REGISTRY_WRITE_LOOKUP_CACHE, which
+ *   signal that we should reset or write the cache, respectively.
+ * @param $name
+ *   The name of the resource, or NULL if either of the REGISTRY_* constants
+ *   is passed in.
+ *
+ * @return
+ *   TRUE if the resource was found, FALSE if not.
+ *   NULL if either of the REGISTRY_* constants is passed in as $type.
+ */
+function _registry_check_code($type, $name = NULL) {
+  static $lookup_cache, $cache_update_needed;
+
+  if ($type == 'class' && class_exists($name) || $type == 'interface' && interface_exists($name) || $type == 'trait' && trait_exists($name)) {
+    return TRUE;
+  }
+
+  if (!isset($lookup_cache)) {
+    $lookup_cache = array();
+    if ($cache = cache_get('lookup_cache', 'cache_bootstrap')) {
+      $lookup_cache = $cache->data;
+    }
+  }
+
+  // When we rebuild the registry, we need to reset this cache so
+  // we don't keep lookups for resources that changed during the rebuild.
+  if ($type == REGISTRY_RESET_LOOKUP_CACHE) {
+    $cache_update_needed = TRUE;
+    $lookup_cache = NULL;
+    return;
+  }
+
+  // Called from drupal_page_footer, we write to permanent storage if there
+  // changes to the lookup cache for this request.
+  if ($type == REGISTRY_WRITE_LOOKUP_CACHE) {
+    if ($cache_update_needed) {
+      cache_set('lookup_cache', $lookup_cache, 'cache_bootstrap');
+    }
+    return;
+  }
+
+  // $type is either 'interface' or 'class', so we only need the first letter to
+  // keep the cache key unique.
+  $cache_key = $type[0] . $name;
+  if (isset($lookup_cache[$cache_key])) {
+    if ($lookup_cache[$cache_key]) {
+      include_once DRUPAL_ROOT . '/' . $lookup_cache[$cache_key];
+    }
+    return (bool) $lookup_cache[$cache_key];
+  }
+
+  // This function may get called when the default database is not active, but
+  // there is no reason we'd ever want to not use the default database for
+  // this query.
+  $file = Database::getConnection('default', 'default')
+    ->select('registry', 'r', array('target' => 'default'))
+    ->fields('r', array('filename'))
+    // Use LIKE here to make the query case-insensitive.
+    ->condition('r.name', db_like($name), 'LIKE')
+    ->condition('r.type', $type)
+    ->execute()
+    ->fetchField();
+
+  // Flag that we've run a lookup query and need to update the cache.
+  $cache_update_needed = TRUE;
+
+  // Misses are valuable information worth caching, so cache even if
+  // $file is FALSE.
+  $lookup_cache[$cache_key] = $file;
+
+  if ($file) {
+    include_once DRUPAL_ROOT . '/' . $file;
+    return TRUE;
+  }
+  else {
+    return FALSE;
+  }
+}
+
+/**
+ * Rescans all enabled modules and rebuilds the registry.
+ *
+ * Rescans all code in modules or includes directories, storing the location of
+ * each interface or class in the database.
+ */
+function registry_rebuild() {
+  system_rebuild_module_data();
+  registry_update();
+}
+
+/**
+ * Updates the registry based on the latest files listed in the database.
+ *
+ * This function should be used when system_rebuild_module_data() does not need
+ * to be called, because it is already known that the list of files in the
+ * {system} table matches those in the file system.
+ *
+ * @return
+ *   TRUE if the registry was rebuilt, FALSE if another thread was rebuilding
+ *   in parallel and the current thread just waited for completion.
+ *
+ * @see registry_rebuild()
+ */
+function registry_update() {
+  // install_system_module() calls module_enable() which calls into this
+  // function during initial system installation, so the lock system is neither
+  // loaded nor does its storage exist yet.
+  $in_installer = drupal_installation_attempted();
+  if (!$in_installer && !lock_acquire(__FUNCTION__)) {
+    // Another request got the lock, wait for it to finish.
+    lock_wait(__FUNCTION__);
+    return FALSE;
+  }
+
+  require_once DRUPAL_ROOT . '/includes/registry.inc';
+  _registry_update();
+
+  if (!$in_installer) {
+    lock_release(__FUNCTION__);
+  }
+  return TRUE;
+}
+
+/**
+ * @} End of "addtogroup registry".
+ */
+
+/**
+ * Provides central static variable storage.
+ *
+ * All functions requiring a static variable to persist or cache data within
+ * a single page request are encouraged to use this function unless it is
+ * absolutely certain that the static variable will not need to be reset during
+ * the page request. By centralizing static variable storage through this
+ * function, other functions can rely on a consistent API for resetting any
+ * other function's static variables.
+ *
+ * Example:
+ * @code
+ * function language_list($field = 'language') {
+ *   $languages = &drupal_static(__FUNCTION__);
+ *   if (!isset($languages)) {
+ *     // If this function is being called for the first time after a reset,
+ *     // query the database and execute any other code needed to retrieve
+ *     // information about the supported languages.
+ *     ...
+ *   }
+ *   if (!isset($languages[$field])) {
+ *     // If this function is being called for the first time for a particular
+ *     // index field, then execute code needed to index the information already
+ *     // available in $languages by the desired field.
+ *     ...
+ *   }
+ *   // Subsequent invocations of this function for a particular index field
+ *   // skip the above two code blocks and quickly return the already indexed
+ *   // information.
+ *   return $languages[$field];
+ * }
+ * function locale_translate_overview_screen() {
+ *   // When building the content for the translations overview page, make
+ *   // sure to get completely fresh information about the supported languages.
+ *   drupal_static_reset('language_list');
+ *   ...
+ * }
+ * @endcode
+ *
+ * In a few cases, a function can have certainty that there is no legitimate
+ * use-case for resetting that function's static variable. This is rare,
+ * because when writing a function, it's hard to forecast all the situations in
+ * which it will be used. A guideline is that if a function's static variable
+ * does not depend on any information outside of the function that might change
+ * during a single page request, then it's ok to use the "static" keyword
+ * instead of the drupal_static() function.
+ *
+ * Example:
+ * @code
+ * function actions_do(...) {
+ *   // $stack tracks the number of recursive calls.
+ *   static $stack;
+ *   $stack++;
+ *   if ($stack > variable_get('actions_max_stack', 35)) {
+ *     ...
+ *     return;
+ *   }
+ *   ...
+ *   $stack--;
+ * }
+ * @endcode
+ *
+ * In a few cases, a function needs a resettable static variable, but the
+ * function is called many times (100+) during a single page request, so
+ * every microsecond of execution time that can be removed from the function
+ * counts. These functions can use a more cumbersome, but faster variant of
+ * calling drupal_static(). It works by storing the reference returned by
+ * drupal_static() in the calling function's own static variable, thereby
+ * removing the need to call drupal_static() for each iteration of the function.
+ * Conceptually, it replaces:
+ * @code
+ * $foo = &drupal_static(__FUNCTION__);
+ * @endcode
+ * with:
+ * @code
+ * // Unfortunately, this does not work.
+ * static $foo = &drupal_static(__FUNCTION__);
+ * @endcode
+ * However, the above line of code does not work, because PHP only allows static
+ * variables to be initializied by literal values, and does not allow static
+ * variables to be assigned to references.
+ * - http://php.net/manual/language.variables.scope.php#language.variables.scope.static
+ * - http://php.net/manual/language.variables.scope.php#language.variables.scope.references
+ * The example below shows the syntax needed to work around both limitations.
+ * For benchmarks and more information, see http://drupal.org/node/619666.
+ *
+ * Example:
+ * @code
+ * function user_access($string, $account = NULL) {
+ *   // Use the advanced drupal_static() pattern, since this is called very often.
+ *   static $drupal_static_fast;
+ *   if (!isset($drupal_static_fast)) {
+ *     $drupal_static_fast['perm'] = &drupal_static(__FUNCTION__);
+ *   }
+ *   $perm = &$drupal_static_fast['perm'];
+ *   ...
+ * }
+ * @endcode
+ *
+ * @param $name
+ *   Globally unique name for the variable. For a function with only one static,
+ *   variable, the function name (e.g. via the PHP magic __FUNCTION__ constant)
+ *   is recommended. For a function with multiple static variables add a
+ *   distinguishing suffix to the function name for each one.
+ * @param $default_value
+ *   Optional default value.
+ * @param $reset
+ *   TRUE to reset one or all variables(s). This parameter is only used
+ *   internally and should not be passed in; use drupal_static_reset() instead.
+ *   (This function's return value should not be used when TRUE is passed in.)
+ *
+ * @return
+ *   Returns a variable by reference.
+ *
+ * @see drupal_static_reset()
+ */
+function &drupal_static($name, $default_value = NULL, $reset = FALSE) {
+  static $data = array(), $default = array();
+  // First check if dealing with a previously defined static variable.
+  if (isset($data[$name]) || array_key_exists($name, $data)) {
+    // Non-NULL $name and both $data[$name] and $default[$name] statics exist.
+    if ($reset) {
+      // Reset pre-existing static variable to its default value.
+      $data[$name] = $default[$name];
+    }
+    return $data[$name];
+  }
+  // Neither $data[$name] nor $default[$name] static variables exist.
+  if (isset($name)) {
+    if ($reset) {
+      // Reset was called before a default is set and yet a variable must be
+      // returned.
+      return $data;
+    }
+    // First call with new non-NULL $name. Initialize a new static variable.
+    $default[$name] = $data[$name] = $default_value;
+    return $data[$name];
+  }
+  // Reset all: ($name == NULL). This needs to be done one at a time so that
+  // references returned by earlier invocations of drupal_static() also get
+  // reset.
+  foreach ($default as $name => $value) {
+    $data[$name] = $value;
+  }
+  // As the function returns a reference, the return should always be a
+  // variable.
+  return $data;
+}
+
+/**
+ * Resets one or all centrally stored static variable(s).
+ *
+ * @param $name
+ *   Name of the static variable to reset. Omit to reset all variables.
+ *   Resetting all variables should only be used, for example, for running unit
+ *   tests with a clean environment.
+ */
+function drupal_static_reset($name = NULL) {
+  drupal_static($name, NULL, TRUE);
+}
+
+/**
+ * Detects whether the current script is running in a command-line environment.
+ */
+function drupal_is_cli() {
+  return (!isset($_SERVER['SERVER_SOFTWARE']) && (php_sapi_name() == 'cli' || (is_numeric($_SERVER['argc']) && $_SERVER['argc'] > 0)));
+}
+
+/**
+ * Formats text for emphasized display in a placeholder inside a sentence.
+ *
+ * Used automatically by format_string().
+ *
+ * @param $text
+ *   The text to format (plain-text).
+ *
+ * @return
+ *   The formatted text (html).
+ */
+function drupal_placeholder($text) {
+  return '<em class="placeholder">' . check_plain($text) . '</em>';
+}
+
+/**
+ * Registers a function for execution on shutdown.
+ *
+ * Wrapper for register_shutdown_function() that catches thrown exceptions to
+ * avoid "Exception thrown without a stack frame in Unknown".
+ *
+ * @param $callback
+ *   The shutdown function to register.
+ * @param ...
+ *   Additional arguments to pass to the shutdown function.
+ *
+ * @return
+ *   Array of shutdown functions to be executed.
+ *
+ * @see register_shutdown_function()
+ * @ingroup php_wrappers
+ */
+function &drupal_register_shutdown_function($callback = NULL) {
+  // We cannot use drupal_static() here because the static cache is reset during
+  // batch processing, which breaks batch handling.
+  static $callbacks = array();
+
+  if (isset($callback)) {
+    // Only register the internal shutdown function once.
+    if (empty($callbacks)) {
+      register_shutdown_function('_drupal_shutdown_function');
+    }
+    $args = func_get_args();
+    array_shift($args);
+    // Save callback and arguments
+    $callbacks[] = array('callback' => $callback, 'arguments' => $args);
+  }
+  return $callbacks;
+}
+
+/**
+ * Executes registered shutdown functions.
+ */
+function _drupal_shutdown_function() {
+  $callbacks = &drupal_register_shutdown_function();
+
+  // Set the CWD to DRUPAL_ROOT as it is not guaranteed to be the same as it
+  // was in the normal context of execution.
+  chdir(DRUPAL_ROOT);
+
+  try {
+    while (list($key, $callback) = each($callbacks)) {
+      call_user_func_array($callback['callback'], $callback['arguments']);
+    }
+  }
+  catch (Exception $exception) {
+    // If we are displaying errors, then do so with no possibility of a further uncaught exception being thrown.
+   require_once DRUPAL_ROOT . '/includes/errors.inc';
+   if (error_displayable()) {
+      print '<h1>Uncaught exception thrown in shutdown function.</h1>';
+      print '<p>' . _drupal_render_exception_safe($exception) . '</p><hr />';
+    }
+  }
+}
+
+/**
+ * Compares the memory required for an operation to the available memory.
+ *
+ * @param $required
+ *   The memory required for the operation, expressed as a number of bytes with
+ *   optional SI or IEC binary unit prefix (e.g. 2, 3K, 5MB, 10G, 6GiB, 8bytes,
+ *   9mbytes).
+ * @param $memory_limit
+ *   (optional) The memory limit for the operation, expressed as a number of
+ *   bytes with optional SI or IEC binary unit prefix (e.g. 2, 3K, 5MB, 10G,
+ *   6GiB, 8bytes, 9mbytes). If no value is passed, the current PHP
+ *   memory_limit will be used. Defaults to NULL.
+ *
+ * @return
+ *   TRUE if there is sufficient memory to allow the operation, or FALSE
+ *   otherwise.
+ */
+function drupal_check_memory_limit($required, $memory_limit = NULL) {
+  if (!isset($memory_limit)) {
+    $memory_limit = ini_get('memory_limit');
+  }
+
+  // There is sufficient memory if:
+  // - No memory limit is set.
+  // - The memory limit is set to unlimited (-1).
+  // - The memory limit is greater than the memory required for the operation.
+  return ((!$memory_limit) || ($memory_limit == -1) || (parse_size($memory_limit) >= parse_size($required)));
+}
+
+/**
+ * Invalidates a PHP file from any active opcode caches.
+ *
+ * If the opcode cache does not support the invalidation of individual files,
+ * the entire cache will be flushed.
+ *
+ * @param string $filepath
+ *   The absolute path of the PHP file to invalidate.
+ */
+function drupal_clear_opcode_cache($filepath) {
+  if (!defined('PHP_VERSION_ID') || PHP_VERSION_ID < 50300) {
+    // Below PHP 5.3, clearstatcache does not accept any function parameters.
+    clearstatcache();
+  }
+  else {
+    clearstatcache(TRUE, $filepath);
+  }
+
+  // Zend OPcache.
+  if (function_exists('opcache_invalidate')) {
+    opcache_invalidate($filepath, TRUE);
+  }
+  // APC.
+  if (function_exists('apc_delete_file')) {
+    // apc_delete_file() throws a PHP warning in case the specified file was
+    // not compiled yet.
+    // @see http://php.net/apc-delete-file
+    @apc_delete_file($filepath);
+  }
+}