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index.php

php 
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<?php

/**
* @file
* Functions that need to be loaded on every Drupal request.
*/

/**
* The current system version.
*/
define('VERSION', '7.28');

/**
* 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]*');

/**
* 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. Uses find_conf_path() to find the current configuration directory.
* 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) {
  return preg_match('/^\[?(?:[a-zA-Z0-9-:\]_]+\.?)+$/', $host);
}

/**
* 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';
  }
  $is_https = isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on';

  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 $filename
*   The filename of the item if it is to be set explicitly rather
*   than by consulting the database.
*
* @return
*   The filename of the requested item or NULL if the item is not found.
*/
function drupal_get_filename($type, $name, $filename = NULL) {
  // The location of files will not change during the request, so do not use
  // drupal_static().
  static $files = array(), $dirs = 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)) {
    $files[$type][$name] = $filename;
  }
  elseif (isset($files[$type][$name])) {
    // nothing
  }
  // Verify that we have an active database connection, before querying
  // the database. This is required because this function is called both
  // before we have a database connection (i.e. during installation) and
  // when a database connection fails.
  else {
    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_exists(DRUPAL_ROOT . '/' . $file)) {
          $files[$type][$name] = $file;
        }
      }
    }
    catch (Exception $e) {
      // The database table may not exist because Drupal is not yet installed,
      // or the database might be down. We have a fallback for this case so we
      // hide the error completely.
    }
    // Fallback to searching the filesystem if the database could not find the
    // file or the file returned by the database is not found.
    if (!isset($files[$type][$name])) {
      // 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;
      }

      if (!isset($dirs[$dir][$extension])) {
        $dirs[$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) {
          $files[$type][$matched_name] = $file->uri;
        }
      }
    }
  }

  if (isset($files[$type][$name])) {
    return $files[$type][$name];
  }
}

/**
* 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 $allow_caching
*   Set to FALSE if you want to prevent this page to get cached.
*
* @return
*   TRUE if the current page can be cached, FALSE otherwise.
*/
function drupal_page_is_cacheable($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.
*
* Also give each page a unique ETag. This will force clients to include both
* an If-Modified-Since header and an If-None-Match header when doing
* conditional requests for the page (required by RFC 2616, section 13.3.4),
* making the validation more robust. This is a workaround for a bug in Mozilla
* Firefox that is triggered when Drupal's caching is enabled and the user
* accesses Drupal via an HTTP proxy (see
* https://bugzilla.mozilla.org/show_bug.cgi?id=269303): When an authenticated
* user requests a page, and then logs out and requests the same page again,
* Firefox may send a conditional request based on the page that was cached
* locally when the user was logged in. If this page did not have an ETag
* header, the request only contains an If-Modified-Since header. The date will
* be recent, because with authenticated users the Last-Modified header always
* refers to the time of the request. If the user accesses Drupal via a proxy
* server, and the proxy already has a cached copy of the anonymous page with an
* older Last-Modified date, the proxy may respond with 304 Not Modified, making
* the client think that the anonymous and authenticated pageviews are
* identical.
*
* @see drupal_page_set_cache()
*/
function drupal_page_header() {
  $headers_sent = &drupal_static(__FUNCTION__, FALSE);
  if ($headers_sent) {
    return TRUE;
  }
  $headers_sent = TRUE;

  $default_headers = array(
    'Expires' => 'Sun, 19 Nov 1978 05:00:00 GMT',
    'Last-Modified' => gmdate(DATE_RFC1123, REQUEST_TIME),
    'Cache-Control' => 'no-cache, must-revalidate, post-check=0, pre-check=0',
    'ETag' => '"' . REQUEST_TIME . '"',
  );
  drupal_send_headers($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_RFC1123, $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.
*
* @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 $options
*   An associative array of additional options, with the following elements:
*   - 'langcode' (defaults to the current language): The language code to
*     translate to a language other than what is used to display the page.
*   - 'context' (defaults to the empty context): The context the source string
*     belongs to.
*
* @return
*   The translated string.
*
* @see st()
* @see get_t()
* @see format_string()
* @ingroup sanitization
*/
function t($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 $text
*   The text to be checked or processed.
*
* @return
*   An HTML safe version of $text, or an empty string if $text is not
*   valid UTF-8.
*
* @see drupal_validate_utf8()
* @ingroup sanitization
*/
function check_plain($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) {
    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 $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 $new_phase
*   A boolean, set to FALSE if calling drupal_bootstrap from inside a
*   function called from drupal_bootstrap (recursion).
*
* @return
*   The most recently completed phase.
*/
function drupal_bootstrap($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;

  // When not recursing, store the phase name so it's not forgotten while
  // recursing.
  if ($new_phase) {
    $final_phase = $phase;
  }
  if (isset($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');
}

/**
* 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);
}

/**
* 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();
}

/**
* 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 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 used on the site
*
* @param $property
*   Optional property of the language object to return
*/
function language_default($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);

        // The right-most IP is the most specific we can trust.
        $ip_address = array_pop($untrusted);
      }
    }
  }

  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().
*
* @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);
}

/**
* 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)) {
    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]) {
      require_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')->query("SELECT filename FROM {registry} WHERE name = :name AND type = :type", array(
      ':name' => $name,
      ':type' => $type,
    ))
    ->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) {
    require_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 a specific named variable, or all variables if $name is NULL.
*   Resetting every variable should only be used, for example, for running
*   unit tests with a clean environment. Should be used only though via
*   function drupal_static_reset() and the return value should not be used in
*   this case.
*
* @return
*   Returns a variable by reference.
*
* @see drupal_static_reset()
*/
function &drupal_static($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 $name
*   Name of the static variable to reset. Omit to reset all variables.
*/
function drupal_static_reset($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)));
}
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