C:/drupal/includes/bootstrap.inc

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<?php
// $Id: bootstrap.inc,v 1.211 2008/05/26 17:12:54 dries Exp $

define('CACHE_PERMANENT', 0);

define('CACHE_TEMPORARY', -1);

define('CACHE_DISABLED', 0);

define('CACHE_NORMAL', 1);

define('CACHE_AGGRESSIVE', 2);

define('WATCHDOG_EMERG', 0);

define('WATCHDOG_ALERT', 1);

define('WATCHDOG_CRITICAL', 2);

define('WATCHDOG_ERROR', 3);

define('WATCHDOG_WARNING', 4);

define('WATCHDOG_NOTICE', 5);

define('WATCHDOG_INFO', 6);

define('WATCHDOG_DEBUG', 7);

define('DRUPAL_BOOTSTRAP_CONFIGURATION', 0);

define('DRUPAL_BOOTSTRAP_EARLY_PAGE_CACHE', 1);

define('DRUPAL_BOOTSTRAP_DATABASE', 2);

define('DRUPAL_BOOTSTRAP_ACCESS', 3);

define('DRUPAL_BOOTSTRAP_SESSION', 4);

define('DRUPAL_BOOTSTRAP_LATE_PAGE_CACHE', 5);

define('DRUPAL_BOOTSTRAP_LANGUAGE', 6);

define('DRUPAL_BOOTSTRAP_PATH', 7);

define('DRUPAL_BOOTSTRAP_FULL', 8);

define('DRUPAL_ANONYMOUS_RID', 1);

define('DRUPAL_AUTHENTICATED_RID', 2);

define('LANGUAGE_NEGOTIATION_NONE', 0);

define('LANGUAGE_NEGOTIATION_PATH_DEFAULT', 1);

define('LANGUAGE_NEGOTIATION_PATH', 2);

define('LANGUAGE_NEGOTIATION_DOMAIN', 3);

function timer_start($name) {
  global $timers;

  list($usec, $sec) = explode(' ', microtime());
  $timers[$name]['start'] = (float)$usec + (float)$sec;
  $timers[$name]['count'] = isset($timers[$name]['count']) ? ++$timers[$name]['count'] : 1;
}

function timer_read($name) {
  global $timers;

  if (isset($timers[$name]['start'])) {
    list($usec, $sec) = explode(' ', microtime());
    $stop = (float)$usec + (float)$sec;
    $diff = round(($stop - $timers[$name]['start']) * 1000, 2);

    if (isset($timers[$name]['time'])) {
      $diff += $timers[$name]['time'];
    }
    return $diff;
  }
}

function timer_stop($name) {
  global $timers;

  $timers[$name]['time'] = timer_read($name);
  unset($timers[$name]['start']);

  return $timers[$name];
}

function conf_path($require_settings = TRUE, $reset = FALSE) {
  static $conf = '';

  if ($conf && !$reset) {
    return $conf;
  }

  $confdir = 'sites';
  $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, $i));
      if (file_exists("$confdir/$dir/settings.php") || (!$require_settings && file_exists("$confdir/$dir"))) {
        $conf = "$confdir/$dir";
        return $conf;
      }
    }
  }
  $conf = "$confdir/default";
  return $conf;
}

function drupal_unset_globals() {
  if (ini_get('register_globals')) {
    $allowed = array('_ENV' => 1, '_GET' => 1, '_POST' => 1, '_COOKIE' => 1, '_FILES' => 1, '_SERVER' => 1, '_REQUEST' => 1, 'GLOBALS' => 1);
    foreach ($GLOBALS as $key => $value) {
      if (!isset($allowed[$key])) {
        unset($GLOBALS[$key]);
      }
    }
  }
}

function conf_init() {
  global $base_url, $base_path, $base_root;

  // Export the following settings.php variables to the global namespace
  global $db_url, $db_prefix, $cookie_domain, $conf, $installed_profile, $update_free_access;
  $conf = array();

  if (file_exists('./' . conf_path() . '/settings.php')) {
    include_once './' . conf_path() . '/settings.php';
  }

  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
    $base_root = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 'https' : 'http';

    // As $_SERVER['HTTP_HOST'] is user input, ensure it only contains
    // characters allowed in hostnames.
    $base_url = $base_root .= '://' . preg_replace('/[^a-z0-9-:._]/i', '', $_SERVER['HTTP_HOST']);

    // $_SERVER['SCRIPT_NAME'] can, in contrast to $_SERVER['PHP_SELF'], not
    // be modified by a visitor.
    if ($dir = trim(dirname($_SERVER['SCRIPT_NAME']), '\,/')) {
      $base_path = "/$dir";
      $base_url .= $base_path;
      $base_path .= '/';
    }
    else {
      $base_path = '/';
    }
  }

  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('://', $base_url, 2);
    // We escape the hostname because it can be modified by a visitor.
    if (!empty($_SERVER['HTTP_HOST'])) {
      $cookie_domain = check_plain($_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', $cookie_domain);
  }
  session_name('SESS' . md5($session_name));
}

function drupal_get_filename($type, $name, $filename = NULL) {
  static $files = array();

  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.
  elseif (db_is_active() && (($file = db_result(db_query("SELECT filename FROM {system} WHERE name = '%s' AND type = '%s'", $name, $type))) && file_exists($file))) {
    $files[$type][$name] = $file;
  }
  else {
    // Fallback to searching the filesystem if the database connection is
    // not established or the requested file is not found.
    $config = conf_path();
    $dir = (($type == 'theme_engine') ? 'themes/engines' : "${type}s");
    $file = (($type == 'theme_engine') ? "$name.engine" : "$name.$type");

    foreach (array("$config/$dir/$file", "$config/$dir/$name/$file", "$dir/$file", "$dir/$name/$file") as $file) {
      if (file_exists($file)) {
        $files[$type][$name] = $file;
        break;
      }
    }
  }

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

function variable_init($conf = array()) {
  // NOTE: caching the variables improves performance by 20% when serving cached pages.
  if ($cached = cache_get('variables', 'cache')) {
    $variables = $cached->data;
  }
  else {
    $result = db_query('SELECT * FROM {variable}');
    while ($variable = db_fetch_object($result)) {
      $variables[$variable->name] = unserialize($variable->value);
    }
    cache_set('variables', $variables);
  }

  foreach ($conf as $name => $value) {
    $variables[$name] = $value;
  }

  return $variables;
}

function variable_get($name, $default) {
  global $conf;

  return isset($conf[$name]) ? $conf[$name] : $default;
}

function variable_set($name, $value) {
  global $conf;

  $serialized_value = serialize($value);
  db_query("UPDATE {variable} SET value = '%s' WHERE name = '%s'", $serialized_value, $name);
  if (!db_affected_rows()) {
    @db_query("INSERT INTO {variable} (name, value) VALUES ('%s', '%s')", $name, $serialized_value);
  }

  cache_clear_all('variables', 'cache');

  $conf[$name] = $value;
}

function variable_del($name) {
  global $conf;

  db_query("DELETE FROM {variable} WHERE name = '%s'", $name);
  cache_clear_all('variables', 'cache');

  unset($conf[$name]);
}


function page_get_cache() {
  global $user, $base_root;

  $cache = NULL;

  if (!$user->uid && $_SERVER['REQUEST_METHOD'] == 'GET' && count(drupal_set_message()) == 0) {
    $cache = cache_get($base_root . request_uri(), 'cache_page');

    if (empty($cache)) {
      ob_start();
    }
  }

  return $cache;
}

function bootstrap_invoke_all($hook) {
  foreach (module_list(TRUE, TRUE) as $module) {
    module_invoke($module, $hook);
  }
}

function drupal_load($type, $name) {
  static $files = array();

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

  $filename = drupal_get_filename($type, $name);

  if ($filename) {
    include_once "./$filename";
    $files[$type][$name] = TRUE;

    return TRUE;
  }

  return FALSE;
}

function drupal_page_header() {
  header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
  header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
  header("Cache-Control: store, no-cache, must-revalidate");
  header("Cache-Control: post-check=0, pre-check=0", FALSE);
}

function drupal_page_cache_header($cache) {
  // Set default values:
  $last_modified = gmdate('D, d M Y H:i:s', $cache->created) . ' GMT';
  $etag = '"' . md5($last_modified) . '"';

  // See if the client has provided the required HTTP headers:
  $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? stripslashes($_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 == $last_modified) {  // if-modified-since must match
    header('HTTP/1.1 304 Not Modified');
    // All 304 responses must send an etag if the 200 response for the same object contained an etag
    header("Etag: $etag");
    exit();
  }

  // Send appropriate response:
  header("Last-Modified: $last_modified");
  header("ETag: $etag");

  // The following headers force validation of cache:
  header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
  header("Cache-Control: must-revalidate");

  if (variable_get('page_compression', TRUE)) {
    // Determine if the browser accepts gzipped data.
    if (@strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') === FALSE && function_exists('gzencode')) {
      // Strip the gzip header and run uncompress.
      $cache->data = gzinflate(substr(substr($cache->data, 10), 0, -8));
    }
    elseif (function_exists('gzencode')) {
      header('Content-Encoding: gzip');
    }
  }

  // Send the original request's headers. We send them one after
  // another so PHP's header() function can deal with duplicate
  // headers.
  $headers = explode("\n", $cache->headers);
  foreach ($headers as $header) {
    header($header);
  }

  print $cache->data;
}

function bootstrap_hooks() {
  return array('boot', 'exit');
}

function drupal_unpack($obj, $field = 'data') {
  if ($obj->$field && $data = unserialize($obj->$field)) {
    foreach ($data as $key => $value) {
      if (!isset($obj->$key)) {
        $obj->$key = $value;
      }
    }
  }
  return $obj;
}

function referer_uri() {
  if (isset($_SERVER['HTTP_REFERER'])) {
    return $_SERVER['HTTP_REFERER'];
  }
}

function check_plain($text) {
  return drupal_validate_utf8($text) ? htmlspecialchars($text, ENT_QUOTES) : '';
}

function drupal_validate_utf8($text) {
  if (strlen($text) == 0) {
    return TRUE;
  }
  return (preg_match('/^./us', $text) == 1);
}

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'];
    }
  }

  return $uri;
}

function watchdog($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE, $link = NULL) {
  global $user, $base_root;

  // Prepare the fields to be logged
  $log_message = array(
    'type'        => $type,
    'message'     => $message,
    'variables'   => $variables,
    'severity'    => $severity,
    'link'        => $link,
    'user'        => $user,
    'request_uri' => $base_root . request_uri(),
    'referer'     => referer_uri(),
    'ip'          => ip_address(),
    'timestamp'   => time(),
    );

  // Call the logging hooks to log/process the message
  foreach (module_implements('watchdog', TRUE) as $module) {
    module_invoke($module, 'watchdog', $log_message);
  }
}

function drupal_set_message($message = NULL, $type = 'status', $repeat = TRUE) {
  if ($message) {
    if (!isset($_SESSION['messages'])) {
      $_SESSION['messages'] = array();
    }

    if (!isset($_SESSION['messages'][$type])) {
      $_SESSION['messages'][$type] = array();
    }

    if ($repeat || !in_array($message, $_SESSION['messages'][$type])) {
      $_SESSION['messages'][$type][] = $message;
    }
  }

  // messages not set when DB connection fails
  return isset($_SESSION['messages']) ? $_SESSION['messages'] : NULL;
}

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();
}

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.
  $blocked_ips = variable_get('blocked_ips', NULL);
  if (isset($blocked_ips) && is_array($blocked_ips)) {
    return in_array($ip, $blocked_ips);
  }
  else {
    $sql = "SELECT 1 FROM {blocked_ips} WHERE ip = '%s'";
    return (bool) db_result(db_query($sql, $ip));
  }
}

function drupal_anonymous_user($session = '') {
  $user = new stdClass();
  $user->uid = 0;
  $user->hostname = ip_address();
  $user->roles = array();
  $user->roles[DRUPAL_ANONYMOUS_RID] = 'anonymous user';
  $user->session = $session;
  $user->cache = 0;
  return $user;
}

function drupal_bootstrap($phase) {
  static $phases = array(DRUPAL_BOOTSTRAP_CONFIGURATION, DRUPAL_BOOTSTRAP_EARLY_PAGE_CACHE, DRUPAL_BOOTSTRAP_DATABASE, DRUPAL_BOOTSTRAP_ACCESS, DRUPAL_BOOTSTRAP_SESSION, DRUPAL_BOOTSTRAP_LATE_PAGE_CACHE, DRUPAL_BOOTSTRAP_LANGUAGE, DRUPAL_BOOTSTRAP_PATH, DRUPAL_BOOTSTRAP_FULL), $phase_index = 0;

  while ($phase >= $phase_index && isset($phases[$phase_index])) {
    $current_phase = $phases[$phase_index];
    unset($phases[$phase_index++]);
    _drupal_bootstrap($current_phase);
  }
}

function _drupal_bootstrap($phase) {
  global $conf;

  switch ($phase) {

    case DRUPAL_BOOTSTRAP_CONFIGURATION:
      drupal_unset_globals();
      // Start a page timer:
      timer_start('page');
      // Initialize the configuration
      conf_init();
      break;

    case DRUPAL_BOOTSTRAP_EARLY_PAGE_CACHE:
      // Allow specifying special cache handlers in settings.php, like
      // using memcached or files for storing cache information.
      require_once variable_get('cache_inc', './includes/cache.inc');
      // If the page_cache_fastpath is set to TRUE in settings.php and
      // page_cache_fastpath (implemented in the special implementation of
      // cache.inc) printed the page and indicated this with a returned TRUE
      // then we are done.
      if (variable_get('page_cache_fastpath', FALSE) && page_cache_fastpath()) {
        exit;
      }
      break;

    case DRUPAL_BOOTSTRAP_DATABASE:
      // Initialize the default database.
      require_once './includes/database.inc';
      db_set_active();
      // Register autoload functions so that we can access classes and interfaces.
      spl_autoload_register('drupal_autoload_class');
      spl_autoload_register('drupal_autoload_interface');
      break;

    case DRUPAL_BOOTSTRAP_ACCESS:
      // Deny access to blocked IP addresses - t() is not yet available.
      if (drupal_is_denied(ip_address())) {
        header('HTTP/1.1 403 Forbidden');
        print 'Sorry, ' . check_plain(ip_address()) . ' has been banned.';
        exit();
      }
      break;

    case DRUPAL_BOOTSTRAP_SESSION:
      require_once variable_get('session_inc', './includes/session.inc');
      session_set_save_handler('sess_open', 'sess_close', 'sess_read', 'sess_write', 'sess_destroy_sid', 'sess_gc');
      session_start();
      break;

    case DRUPAL_BOOTSTRAP_LATE_PAGE_CACHE:
      // Initialize configuration variables, using values from settings.php if available.
      $conf = variable_init(isset($conf) ? $conf : array());
      // Load module handling.
      require_once './includes/module.inc';
      $cache_mode = variable_get('cache', CACHE_DISABLED);
      // Get the page from the cache.
      $cache = $cache_mode == CACHE_DISABLED ? '' : page_get_cache();
      // If the skipping of the bootstrap hooks is not enforced, call hook_boot.
      if ($cache_mode != CACHE_AGGRESSIVE) {
        bootstrap_invoke_all('boot');
      }
      // If there is a cached page, display it.
      if ($cache) {
        drupal_page_cache_header($cache);
        // If the skipping of the bootstrap hooks is not enforced, call hook_exit.
        if ($cache_mode != CACHE_AGGRESSIVE) {
          bootstrap_invoke_all('exit');
        }
        // We are done.
        exit;
      }
      // Prepare for non-cached page workflow.
      drupal_page_header();
      break;

    case DRUPAL_BOOTSTRAP_LANGUAGE:
      drupal_init_language();
      break;

    case DRUPAL_BOOTSTRAP_PATH:
      require_once './includes/path.inc';
      // Initialize $_GET['q'] prior to loading modules and invoking hook_init().
      drupal_init_path();
      break;

    case DRUPAL_BOOTSTRAP_FULL:
      require_once './includes/common.inc';
      _drupal_bootstrap_full();
      break;
  }
}

function drupal_maintenance_theme() {
  require_once './includes/theme.maintenance.inc';
  _drupal_maintenance_theme();
}

function get_t() {
  static $t;
  if (is_null($t)) {
    $t = function_exists('install_main') ? 'st' : 't';
  }
  return $t;
}

function drupal_init_language() {
  global $language, $user;

  // Ensure the language is correctly returned, even without multilanguage support.
  // Useful for eg. XML/HTML 'lang' attributes.
  if (variable_get('language_count', 1) == 1) {
    $language = language_default();
  }
  else {
    include_once './includes/language.inc';
    $language = language_initialize();
  }
}

function language_list($field = 'language', $reset = FALSE) {
  static $languages = NULL;

  // Reset language list
  if ($reset) {
    $languages = NULL;
  }

  // Init language list
  if (!isset($languages)) {
    if (variable_get('language_count', 1) > 1 || module_exists('locale')) {
      $result = db_query('SELECT * FROM {languages} ORDER BY weight ASC, name ASC');
      while ($row = db_fetch_object($result)) {
        $languages['language'][$row->language] = $row;
      }
    }
    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];
}

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;
}

function ip_address() {
  static $ip_address = NULL;

  if (!isset($ip_address)) {
    $ip_address = $_SERVER['REMOTE_ADDR'];
    if (variable_get('reverse_proxy', 0) && array_key_exists('HTTP_X_FORWARDED_FOR', $_SERVER)) {
      // If an array of known reverse proxy IPs is provided, then trust
      // the XFF header if request really comes from one of them.
      $reverse_proxy_addresses = variable_get('reverse_proxy_addresses', array());
      if (!empty($reverse_proxy_addresses) && in_array($ip_address, $reverse_proxy_addresses, TRUE)) {
        // If there are several arguments, we need to check the most
        // recently added one, i.e. the last one.
        $ip_address = array_pop(explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']));
      }
    }
  }

  return $ip_address;
}

function drupal_function_exists($function) {
  static $checked = array();

  if (defined('MAINTENANCE_MODE')) {
    return function_exists($function);
  }

  if (isset($checked[$function])) {
    return $checked[$function];
  }
  $checked[$function] = FALSE;

  if (function_exists($function)) {
    registry_mark_code('function', $function);
    $checked[$function] = TRUE;
    return TRUE;
  }

  $file = db_result(db_query("SELECT filename FROM {registry} WHERE name = '%s' AND type = '%s'", $function, 'function'));
  if ($file) {
    require_once($file);
    $checked[$function] = function_exists($function);
    if ($checked[$function]) {
      registry_mark_code('function', $function);
    }
  }

  return $checked[$function];
}

function drupal_autoload_interface($interface) {
  return _registry_check_code('interface', $interface);
}

function drupal_autoload_class($class) {
  return _registry_check_code('class', $class);
}

function _registry_check_code($type, $name) {
  $file = db_result(db_query("SELECT filename FROM {registry} WHERE name = '%s' AND type = '%s'", $name, $type));
  if ($file) {
    require_once($file);
    registry_mark_code($type, $name);
    return TRUE;
  }
}

function registry_mark_code($type, $name, $return = FALSE) {
  static $resources = array();

  if ($type && $name) {
    if (!isset($resources[$type])) {
      $resources[$type] = array();
    }
    if (!in_array($name, $resources[$type])) {
      $resources[$type][] = $name;
    }
  }

  if ($return) {
    return $resources;
  }
}

function drupal_rebuild_code_registry() {
  require_once './includes/registry.inc';
  _drupal_rebuild_code_registry();
}

function registry_cache_hook_implementations($hook, $write_to_persistent_cache = FALSE) {
  static $implementations;

  if ($hook) {
    // Newer is always better, so overwrite anything that's come before.
    $implementations[$hook['hook']] = $hook['modules'];
  }

  if ($write_to_persistent_cache === TRUE) {
    // Only write this to cache if the implementations data we are going to cache
    // is different to what we loaded earlier in the request.
    if ($implementations != registry_get_hook_implementations_cache()) {
      cache_set('hooks', $implementations, 'cache_registry');
    }
  }
}

function registry_cache_path_files() {
  if ($used_code = registry_mark_code(NULL, NULL, TRUE)) {
    $files = array();
    $type_sql = array();
    $params = array();
    foreach ($used_code as $type => $names) {
      $type_sql[] = "(name IN (" . db_placeholders($names, 'varchar') . ") AND type = '%s')";
      $params = array_merge($params, $names);
      $params[] = $type;
    }
    $res = db_query("SELECT DISTINCT filename FROM {registry} WHERE " . implode(' OR ', $type_sql), $params);
    while ($row = db_fetch_object($res)) {
      $files[] = $row->filename;
    }
    if ($files) {
      sort($files);
      // Only write this to cache if the file list we are going to cache
      // is different to what we loaded earlier in the request.
      if ($files != registry_load_path_files(TRUE)) {
        $menu = menu_get_item();
        cache_set('registry:' . $menu['path'], implode(';', $files), 'cache_registry');
      }
    }
  }
}

function registry_load_path_files($return = FALSE) {
  static $file_cache_data = array();
  if ($return) {
    sort($file_cache_data);
    return $file_cache_data;
  }
  $menu = menu_get_item();
  $cache = cache_get('registry:' . $menu['path'], 'cache_registry');
  if (!empty($cache->data)) {
    foreach(explode(';', $cache->data) as $file) {
      require_once($file);
      $file_cache_data[] = $file;
    }
  }
}

function registry_get_hook_implementations_cache() {
  static $implementations;
  if ($implementations === NULL) {
    if ($cache = cache_get('hooks', 'cache_registry')) {
      $implementations = $cache->data;
    }
    else {
      $implementations = array();
    }
  }
  return $implementations;
}

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