Source: /includes/bootstrap.inc - 3385 lines - 115594 bytes - Summary - Text - Print

   1  <?php
   2  
   3  /**
   4   * @file
   5   * Functions that need to be loaded on every Drupal request.
   6   */
   7  
   8  /**
   9   * The current system version.
  10   */
  11  define('VERSION', '7.17');
  12  
  13  /**
  14   * Core API compatibility.
  15   */
  16  define('DRUPAL_CORE_COMPATIBILITY', '7.x');
  17  
  18  /**
  19   * Minimum supported version of PHP.
  20   */
  21  define('DRUPAL_MINIMUM_PHP', '5.2.4');
  22  
  23  /**
  24   * Minimum recommended value of PHP memory_limit.
  25   */
  26  define('DRUPAL_MINIMUM_PHP_MEMORY_LIMIT', '32M');
  27  
  28  /**
  29   * Error reporting level: display no errors.
  30   */
  31  define('ERROR_REPORTING_HIDE', 0);
  32  
  33  /**
  34   * Error reporting level: display errors and warnings.
  35   */
  36  define('ERROR_REPORTING_DISPLAY_SOME', 1);
  37  
  38  /**
  39   * Error reporting level: display all messages.
  40   */
  41  define('ERROR_REPORTING_DISPLAY_ALL', 2);
  42  
  43  /**
  44   * Indicates that the item should never be removed unless explicitly selected.
  45   *
  46   * The item may be removed using cache_clear_all() with a cache ID.
  47   */
  48  define('CACHE_PERMANENT', 0);
  49  
  50  /**
  51   * Indicates that the item should be removed at the next general cache wipe.
  52   */
  53  define('CACHE_TEMPORARY', -1);
  54  
  55  /**
  56   * @defgroup logging_severity_levels Logging severity levels
  57   * @{
  58   * Logging severity levels as defined in RFC 3164.
  59   *
  60   * The WATCHDOG_* constant definitions correspond to the logging severity levels
  61   * defined in RFC 3164, section 4.1.1. PHP supplies predefined LOG_* constants
  62   * for use in the syslog() function, but their values on Windows builds do not
  63   * correspond to RFC 3164. The associated PHP bug report was closed with the
  64   * comment, "And it's also not a bug, as Windows just have less log levels,"
  65   * and "So the behavior you're seeing is perfectly normal."
  66   *
  67   * @see http://www.faqs.org/rfcs/rfc3164.html
  68   * @see http://bugs.php.net/bug.php?id=18090
  69   * @see http://php.net/manual/function.syslog.php
  70   * @see http://php.net/manual/network.constants.php
  71   * @see watchdog()
  72   * @see watchdog_severity_levels()
  73   */
  74  
  75  /**
  76   * Log message severity -- Emergency: system is unusable.
  77   */
  78  define('WATCHDOG_EMERGENCY', 0);
  79  
  80  /**
  81   * Log message severity -- Alert: action must be taken immediately.
  82   */
  83  define('WATCHDOG_ALERT', 1);
  84  
  85  /**
  86   * Log message severity -- Critical conditions.
  87   */
  88  define('WATCHDOG_CRITICAL', 2);
  89  
  90  /**
  91   * Log message severity -- Error conditions.
  92   */
  93  define('WATCHDOG_ERROR', 3);
  94  
  95  /**
  96   * Log message severity -- Warning conditions.
  97   */
  98  define('WATCHDOG_WARNING', 4);
  99  
 100  /**
 101   * Log message severity -- Normal but significant conditions.
 102   */
 103  define('WATCHDOG_NOTICE', 5);
 104  
 105  /**
 106   * Log message severity -- Informational messages.
 107   */
 108  define('WATCHDOG_INFO', 6);
 109  
 110  /**
 111   * Log message severity -- Debug-level messages.
 112   */
 113  define('WATCHDOG_DEBUG', 7);
 114  
 115  /**
 116   * @} End of "defgroup logging_severity_levels".
 117   */
 118  
 119  /**
 120   * First bootstrap phase: initialize configuration.
 121   */
 122  define('DRUPAL_BOOTSTRAP_CONFIGURATION', 0);
 123  
 124  /**
 125   * Second bootstrap phase: try to serve a cached page.
 126   */
 127  define('DRUPAL_BOOTSTRAP_PAGE_CACHE', 1);
 128  
 129  /**
 130   * Third bootstrap phase: initialize database layer.
 131   */
 132  define('DRUPAL_BOOTSTRAP_DATABASE', 2);
 133  
 134  /**
 135   * Fourth bootstrap phase: initialize the variable system.
 136   */
 137  define('DRUPAL_BOOTSTRAP_VARIABLES', 3);
 138  
 139  /**
 140   * Fifth bootstrap phase: initialize session handling.
 141   */
 142  define('DRUPAL_BOOTSTRAP_SESSION', 4);
 143  
 144  /**
 145   * Sixth bootstrap phase: set up the page header.
 146   */
 147  define('DRUPAL_BOOTSTRAP_PAGE_HEADER', 5);
 148  
 149  /**
 150   * Seventh bootstrap phase: find out language of the page.
 151   */
 152  define('DRUPAL_BOOTSTRAP_LANGUAGE', 6);
 153  
 154  /**
 155   * Final bootstrap phase: Drupal is fully loaded; validate and fix input data.
 156   */
 157  define('DRUPAL_BOOTSTRAP_FULL', 7);
 158  
 159  /**
 160   * Role ID for anonymous users; should match what's in the "role" table.
 161   */
 162  define('DRUPAL_ANONYMOUS_RID', 1);
 163  
 164  /**
 165   * Role ID for authenticated users; should match what's in the "role" table.
 166   */
 167  define('DRUPAL_AUTHENTICATED_RID', 2);
 168  
 169  /**
 170   * The number of bytes in a kilobyte.
 171   *
 172   * For more information, visit http://en.wikipedia.org/wiki/Kilobyte.
 173   */
 174  define('DRUPAL_KILOBYTE', 1024);
 175  
 176  /**
 177   * The language code used when no language is explicitly assigned.
 178   *
 179   * Defined by ISO639-2 for "Undetermined".
 180   */
 181  define('LANGUAGE_NONE', 'und');
 182  
 183  /**
 184   * The type of language used to define the content language.
 185   */
 186  define('LANGUAGE_TYPE_CONTENT', 'language_content');
 187  
 188  /**
 189   * The type of language used to select the user interface.
 190   */
 191  define('LANGUAGE_TYPE_INTERFACE', 'language');
 192  
 193  /**
 194   * The type of language used for URLs.
 195   */
 196  define('LANGUAGE_TYPE_URL', 'language_url');
 197  
 198  /**
 199   * Language written left to right. Possible value of $language->direction.
 200   */
 201  define('LANGUAGE_LTR', 0);
 202  
 203  /**
 204   * Language written right to left. Possible value of $language->direction.
 205   */
 206  define('LANGUAGE_RTL', 1);
 207  
 208  /**
 209   * Time of the current request in seconds elapsed since the Unix Epoch.
 210   *
 211   * This differs from $_SERVER['REQUEST_TIME'], which is stored as a float
 212   * since PHP 5.4.0. Float timestamps confuse most PHP functions
 213   * (including date_create()).
 214   *
 215   * @see http://php.net/manual/reserved.variables.server.php
 216   * @see http://php.net/manual/function.time.php
 217   */
 218  define('REQUEST_TIME', (int) $_SERVER['REQUEST_TIME']);
 219  
 220  /**
 221   * Flag for drupal_set_title(); text is not sanitized, so run check_plain().
 222   */
 223  define('CHECK_PLAIN', 0);
 224  
 225  /**
 226   * Flag for drupal_set_title(); text has already been sanitized.
 227   */
 228  define('PASS_THROUGH', -1);
 229  
 230  /**
 231   * Signals that the registry lookup cache should be reset.
 232   */
 233  define('REGISTRY_RESET_LOOKUP_CACHE', 1);
 234  
 235  /**
 236   * Signals that the registry lookup cache should be written to storage.
 237   */
 238  define('REGISTRY_WRITE_LOOKUP_CACHE', 2);
 239  
 240  /**
 241   * Regular expression to match PHP function names.
 242   *
 243   * @see http://php.net/manual/en/language.functions.php
 244   */
 245  define('DRUPAL_PHP_FUNCTION_PATTERN', '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*');
 246  
 247  /**
 248   * Provides a caching wrapper to be used in place of large array structures.
 249   *
 250   * This class should be extended by systems that need to cache large amounts
 251   * of data and have it represented as an array to calling functions. These
 252   * arrays can become very large, so ArrayAccess is used to allow different
 253   * strategies to be used for caching internally (lazy loading, building caches
 254   * over time etc.). This can dramatically reduce the amount of data that needs
 255   * to be loaded from cache backends on each request, and memory usage from
 256   * static caches of that same data.
 257   *
 258   * Note that array_* functions do not work with ArrayAccess. Systems using
 259   * DrupalCacheArray should use this only internally. If providing API functions
 260   * that return the full array, this can be cached separately or returned
 261   * directly. However since DrupalCacheArray holds partial content by design, it
 262   * should be a normal PHP array or otherwise contain the full structure.
 263   *
 264   * Note also that due to limitations in PHP prior to 5.3.4, it is impossible to
 265   * write directly to the contents of nested arrays contained in this object.
 266   * Only writes to the top-level array elements are possible. So if you
 267   * previously had set $object['foo'] = array(1, 2, 'bar' => 'baz'), but later
 268   * want to change the value of 'bar' from 'baz' to 'foobar', you cannot do so
 269   * a targeted write like $object['foo']['bar'] = 'foobar'. Instead, you must
 270   * overwrite the entire top-level 'foo' array with the entire set of new
 271   * values: $object['foo'] = array(1, 2, 'bar' => 'foobar'). Due to this same
 272   * limitation, attempts to create references to any contained data, nested or
 273   * otherwise, will fail silently. So $var = &$object['foo'] will not throw an
 274   * error, and $var will be populated with the contents of $object['foo'], but
 275   * that data will be passed by value, not reference. For more information on
 276   * the PHP limitation, see the note in the official PHP documentation at·
 277   * http://php.net/manual/en/arrayaccess.offsetget.php on
 278   * ArrayAccess::offsetGet().
 279   *
 280   * By default, the class accounts for caches where calling functions might
 281   * request keys in the array that won't exist even after a cache rebuild. This
 282   * prevents situations where a cache rebuild would be triggered over and over
 283   * due to a 'missing' item. These cases are stored internally as a value of
 284   * NULL. This means that the offsetGet() and offsetExists() methods
 285   * must be overridden if caching an array where the top level values can
 286   * legitimately be NULL, and where $object->offsetExists() needs to correctly
 287   * return (equivalent to array_key_exists() vs. isset()). This should not
 288   * be necessary in the majority of cases.
 289   *
 290   * Classes extending this class must override at least the
 291   * resolveCacheMiss() method to have a working implementation.
 292   *
 293   * offsetSet() is not overridden by this class by default. In practice this
 294   * means that assigning an offset via arrayAccess will only apply while the
 295   * object is in scope and will not be written back to the persistent cache.
 296   * This follows a similar pattern to static vs. persistent caching in
 297   * procedural code. Extending classes may wish to alter this behavior, for
 298   * example by overriding offsetSet() and adding an automatic call to persist().
 299   *
 300   * @see SchemaCache
 301   */
 302  abstract class DrupalCacheArray implements ArrayAccess {
 303  
 304    /**
 305     * A cid to pass to cache_set() and cache_get().
 306     */
 307    protected $cid;
 308  
 309    /**
 310     * A bin to pass to cache_set() and cache_get().
 311     */
 312    protected $bin;
 313  
 314    /**
 315     * An array of keys to add to the cache at the end of the request.
 316     */
 317    protected $keysToPersist = array();
 318  
 319    /**
 320     * Storage for the data itself.
 321     */
 322    protected $storage = array();
 323  
 324    /**
 325     * Constructs a DrupalCacheArray object.
 326     *
 327     * @param $cid
 328     *   The cid for the array being cached.
 329     * @param $bin
 330     *   The bin to cache the array.
 331     */
 332    public function __construct($cid, $bin) {
 333      $this->cid = $cid;
 334      $this->bin = $bin;
 335  
 336      if ($cached = cache_get($this->cid, $this->bin)) {
 337       $this->storage = $cached->data;
 338      }
 339    }
 340  
 341    /**
 342     * Implements ArrayAccess::offsetExists().
 343     */
 344    public function offsetExists($offset) {
 345      return $this->offsetGet($offset) !== NULL;
 346    }
 347  
 348    /**
 349     * Implements ArrayAccess::offsetGet().
 350     */
 351    public function offsetGet($offset) {
 352      if (isset($this->storage[$offset]) || array_key_exists($offset, $this->storage)) {
 353        return $this->storage[$offset];
 354      }
 355      else {
 356        return $this->resolveCacheMiss($offset);
 357      }
 358    }
 359  
 360    /**
 361     * Implements ArrayAccess::offsetSet().
 362     */
 363    public function offsetSet($offset, $value) {
 364      $this->storage[$offset] = $value;
 365    }
 366  
 367    /**
 368     * Implements ArrayAccess::offsetUnset().
 369     */
 370    public function offsetUnset($offset) {
 371      unset($this->storage[$offset]);
 372    }
 373  
 374    /**
 375     * Flags an offset value to be written to the persistent cache.
 376     *
 377     * If a value is assigned to a cache object with offsetSet(), by default it
 378     * will not be written to the persistent cache unless it is flagged with this
 379     * method. This allows items to be cached for the duration of a request,
 380     * without necessarily writing back to the persistent cache at the end.
 381     *
 382     * @param $offset
 383     *   The array offset that was request.
 384     * @param $persist
 385     *   Optional boolean to specify whether the offset should be persisted or
 386     *   not, defaults to TRUE. When called with $persist = FALSE the offset will
 387     *   be unflagged so that it will not written at the end of the request.
 388     */
 389    protected function persist($offset, $persist = TRUE) {
 390      $this->keysToPersist[$offset] = $persist;
 391    }
 392  
 393    /**
 394     * Resolves a cache miss.
 395     *
 396     * When an offset is not found in the object, this is treated as a cache
 397     * miss. This method allows classes implementing the interface to look up
 398     * the actual value and allow it to be cached.
 399     *
 400     * @param $offset
 401     *   The offset that was requested.
 402     *
 403     * @return
 404     *   The value of the offset, or NULL if no value was found.
 405     */
 406    abstract protected function resolveCacheMiss($offset);
 407  
 408    /**
 409     * Writes a value to the persistent cache immediately.
 410     *
 411     * @param $data
 412     *   The data to write to the persistent cache.
 413     * @param $lock
 414     *   Whether to acquire a lock before writing to cache.
 415     */
 416    protected function set($data, $lock = TRUE) {
 417      // Lock cache writes to help avoid stampedes.
 418      // To implement locking for cache misses, override __construct().
 419      $lock_name = $this->cid . ':' . $this->bin;
 420      if (!$lock || lock_acquire($lock_name)) {
 421        if ($cached = cache_get($this->cid, $this->bin)) {
 422          $data = $cached->data + $data;
 423        }
 424        cache_set($this->cid, $data, $this->bin);
 425        if ($lock) {
 426          lock_release($lock_name);
 427        }
 428      }
 429    }
 430  
 431    /**
 432     * Destructs the DrupalCacheArray object.
 433     */
 434    public function __destruct() {
 435      $data = array();
 436      foreach ($this->keysToPersist as $offset => $persist) {
 437        if ($persist) {
 438          $data[$offset] = $this->storage[$offset];
 439        }
 440      }
 441      if (!empty($data)) {
 442        $this->set($data);
 443      }
 444    }
 445  }
 446  
 447  /**
 448   * Starts the timer with the specified name.
 449   *
 450   * If you start and stop the same timer multiple times, the measured intervals
 451   * will be accumulated.
 452   *
 453   * @param $name
 454   *   The name of the timer.
 455   */
 456  function timer_start($name) {
 457    global $timers;
 458  
 459    $timers[$name]['start'] = microtime(TRUE);
 460    $timers[$name]['count'] = isset($timers[$name]['count']) ? ++$timers[$name]['count'] : 1;
 461  }
 462  
 463  /**
 464   * Reads the current timer value without stopping the timer.
 465   *
 466   * @param $name
 467   *   The name of the timer.
 468   *
 469   * @return
 470   *   The current timer value in ms.
 471   */
 472  function timer_read($name) {
 473    global $timers;
 474  
 475    if (isset($timers[$name]['start'])) {
 476      $stop = microtime(TRUE);
 477      $diff = round(($stop - $timers[$name]['start']) * 1000, 2);
 478  
 479      if (isset($timers[$name]['time'])) {
 480        $diff += $timers[$name]['time'];
 481      }
 482      return $diff;
 483    }
 484    return $timers[$name]['time'];
 485  }
 486  
 487  /**
 488   * Stops the timer with the specified name.
 489   *
 490   * @param $name
 491   *   The name of the timer.
 492   *
 493   * @return
 494   *   A timer array. The array contains the number of times the timer has been
 495   *   started and stopped (count) and the accumulated timer value in ms (time).
 496   */
 497  function timer_stop($name) {
 498    global $timers;
 499  
 500    if (isset($timers[$name]['start'])) {
 501      $stop = microtime(TRUE);
 502      $diff = round(($stop - $timers[$name]['start']) * 1000, 2);
 503      if (isset($timers[$name]['time'])) {
 504        $timers[$name]['time'] += $diff;
 505      }
 506      else {
 507        $timers[$name]['time'] = $diff;
 508      }
 509      unset($timers[$name]['start']);
 510    }
 511  
 512    return $timers[$name];
 513  }
 514  
 515  /**
 516   * Returns the appropriate configuration directory.
 517   *
 518   * Returns the configuration path based on the site's hostname, port, and
 519   * pathname. Uses find_conf_path() to find the current configuration directory.
 520   * See default.settings.php for examples on how the URL is converted to a
 521   * directory.
 522   *
 523   * @param bool $require_settings
 524   *   Only configuration directories with an existing settings.php file
 525   *   will be recognized. Defaults to TRUE. During initial installation,
 526   *   this is set to FALSE so that Drupal can detect a matching directory,
 527   *   then create a new settings.php file in it.
 528   * @param bool $reset
 529   *   Force a full search for matching directories even if one had been
 530   *   found previously. Defaults to FALSE.
 531   *
 532   * @return
 533   *   The path of the matching directory.
 534   *
 535   * @see default.settings.php
 536   */
 537  function conf_path($require_settings = TRUE, $reset = FALSE) {
 538    $conf = &drupal_static(__FUNCTION__, '');
 539  
 540    if ($conf && !$reset) {
 541      return $conf;
 542    }
 543  
 544    $confdir = 'sites';
 545  
 546    $sites = array();
 547    if (file_exists(DRUPAL_ROOT . '/' . $confdir . '/sites.php')) {
 548      // This will overwrite $sites with the desired mappings.
 549      include(DRUPAL_ROOT . '/' . $confdir . '/sites.php');
 550    }
 551  
 552    $uri = explode('/', $_SERVER['SCRIPT_NAME'] ? $_SERVER['SCRIPT_NAME'] : $_SERVER['SCRIPT_FILENAME']);
 553    $server = explode('.', implode('.', array_reverse(explode(':', rtrim($_SERVER['HTTP_HOST'], '.')))));
 554    for ($i = count($uri) - 1; $i > 0; $i--) {
 555      for ($j = count($server); $j > 0; $j--) {
 556        $dir = implode('.', array_slice($server, -$j)) . implode('.', array_slice($uri, 0, $i));
 557        if (isset($sites[$dir]) && file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $sites[$dir])) {
 558          $dir = $sites[$dir];
 559        }
 560        if (file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $dir . '/settings.php') || (!$require_settings && file_exists(DRUPAL_ROOT . '/' . $confdir . '/' . $dir))) {
 561          $conf = "$confdir/$dir";
 562          return $conf;
 563        }
 564      }
 565    }
 566    $conf = "$confdir/default";
 567    return $conf;
 568  }
 569  
 570  /**
 571   * Sets appropriate server variables needed for command line scripts to work.
 572   *
 573   * This function can be called by command line scripts before bootstrapping
 574   * Drupal, to ensure that the page loads with the desired server parameters.
 575   * This is because many parts of Drupal assume that they are running in a web
 576   * browser and therefore use information from the global PHP $_SERVER variable
 577   * that does not get set when Drupal is run from the command line.
 578   *
 579   * In many cases, the default way in which this function populates the $_SERVER
 580   * variable is sufficient, and it can therefore be called without passing in
 581   * any input. However, command line scripts running on a multisite installation
 582   * (or on any installation that has settings.php stored somewhere other than
 583   * the sites/default folder) need to pass in the URL of the site to allow
 584   * Drupal to detect the correct location of the settings.php file. Passing in
 585   * the 'url' parameter is also required for functions like request_uri() to
 586   * return the expected values.
 587   *
 588   * Most other parameters do not need to be passed in, but may be necessary in
 589   * some cases; for example, if Drupal's ip_address() function needs to return
 590   * anything but the standard localhost value ('127.0.0.1'), the command line
 591   * script should pass in the desired value via the 'REMOTE_ADDR' key.
 592   *
 593   * @param $variables
 594   *   (optional) An associative array of variables within $_SERVER that should
 595   *   be replaced. If the special element 'url' is provided in this array, it
 596   *   will be used to populate some of the server defaults; it should be set to
 597   *   the URL of the current page request, excluding any $_GET request but
 598   *   including the script name (e.g., http://www.example.com/mysite/index.php).
 599   *
 600   * @see conf_path()
 601   * @see request_uri()
 602   * @see ip_address()
 603   */
 604  function drupal_override_server_variables($variables = array()) {
 605    // Allow the provided URL to override any existing values in $_SERVER.
 606    if (isset($variables['url'])) {
 607      $url = parse_url($variables['url']);
 608      if (isset($url['host'])) {
 609        $_SERVER['HTTP_HOST'] = $url['host'];
 610      }
 611      if (isset($url['path'])) {
 612        $_SERVER['SCRIPT_NAME'] = $url['path'];
 613      }
 614      unset($variables['url']);
 615    }
 616    // Define default values for $_SERVER keys. These will be used if $_SERVER
 617    // does not already define them and no other values are passed in to this
 618    // function.
 619    $defaults = array(
 620      'HTTP_HOST' => 'localhost',
 621      'SCRIPT_NAME' => NULL,
 622      'REMOTE_ADDR' => '127.0.0.1',
 623      'REQUEST_METHOD' => 'GET',
 624      'SERVER_NAME' => NULL,
 625      'SERVER_SOFTWARE' => NULL,
 626      'HTTP_USER_AGENT' => NULL,
 627    );
 628    // Replace elements of the $_SERVER array, as appropriate.
 629    $_SERVER = $variables + $_SERVER + $defaults;
 630  }
 631  
 632  /**
 633   * Initializes the PHP environment.
 634   */
 635  function drupal_environment_initialize() {
 636    if (!isset($_SERVER['HTTP_REFERER'])) {
 637      $_SERVER['HTTP_REFERER'] = '';
 638    }
 639    if (!isset($_SERVER['SERVER_PROTOCOL']) || ($_SERVER['SERVER_PROTOCOL'] != 'HTTP/1.0' && $_SERVER['SERVER_PROTOCOL'] != 'HTTP/1.1')) {
 640      $_SERVER['SERVER_PROTOCOL'] = 'HTTP/1.0';
 641    }
 642  
 643    if (isset($_SERVER['HTTP_HOST'])) {
 644      // As HTTP_HOST is user input, ensure it only contains characters allowed
 645      // in hostnames. See RFC 952 (and RFC 2181).
 646      // $_SERVER['HTTP_HOST'] is lowercased here per specifications.
 647      $_SERVER['HTTP_HOST'] = strtolower($_SERVER['HTTP_HOST']);
 648      if (!drupal_valid_http_host($_SERVER['HTTP_HOST'])) {
 649        // HTTP_HOST is invalid, e.g. if containing slashes it may be an attack.
 650        header($_SERVER['SERVER_PROTOCOL'] . ' 400 Bad Request');
 651        exit;
 652      }
 653    }
 654    else {
 655      // Some pre-HTTP/1.1 clients will not send a Host header. Ensure the key is
 656      // defined for E_ALL compliance.
 657      $_SERVER['HTTP_HOST'] = '';
 658    }
 659  
 660    // When clean URLs are enabled, emulate ?q=foo/bar using REQUEST_URI. It is
 661    // not possible to append the query string using mod_rewrite without the B
 662    // flag (this was added in Apache 2.2.8), because mod_rewrite unescapes the
 663    // path before passing it on to PHP. This is a problem when the path contains
 664    // e.g. "&" or "%" that have special meanings in URLs and must be encoded.
 665    $_GET['q'] = request_path();
 666  
 667    // Enforce E_ALL, but allow users to set levels not part of E_ALL.
 668    error_reporting(E_ALL | error_reporting());
 669  
 670    // Override PHP settings required for Drupal to work properly.
 671    // sites/default/default.settings.php contains more runtime settings.
 672    // The .htaccess file contains settings that cannot be changed at runtime.
 673  
 674    // Don't escape quotes when reading files from the database, disk, etc.
 675    ini_set('magic_quotes_runtime', '0');
 676    // Use session cookies, not transparent sessions that puts the session id in
 677    // the query string.
 678    ini_set('session.use_cookies', '1');
 679    ini_set('session.use_only_cookies', '1');
 680    ini_set('session.use_trans_sid', '0');
 681    // Don't send HTTP headers using PHP's session handler.
 682    ini_set('session.cache_limiter', 'none');
 683    // Use httponly session cookies.
 684    ini_set('session.cookie_httponly', '1');
 685  
 686    // Set sane locale settings, to ensure consistent string, dates, times and
 687    // numbers handling.
 688    setlocale(LC_ALL, 'C');
 689  }
 690  
 691  /**
 692   * Validates that a hostname (for example $_SERVER['HTTP_HOST']) is safe.
 693   *
 694   * @return
 695   *  TRUE if only containing valid characters, or FALSE otherwise.
 696   */
 697  function drupal_valid_http_host($host) {
 698    return preg_match('/^\[?(?:[a-zA-Z0-9-:\]_]+\.?)+$/', $host);
 699  }
 700  
 701  /**
 702   * Sets the base URL, cookie domain, and session name from configuration.
 703   */
 704  function drupal_settings_initialize() {
 705    global $base_url, $base_path, $base_root;
 706  
 707    // Export these settings.php variables to the global namespace.
 708    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;
 709    $conf = array();
 710  
 711    if (file_exists(DRUPAL_ROOT . '/' . conf_path() . '/settings.php')) {
 712      include_once DRUPAL_ROOT . '/' . conf_path() . '/settings.php';
 713    }
 714    $is_https = isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on';
 715  
 716    if (isset($base_url)) {
 717      // Parse fixed base URL from settings.php.
 718      $parts = parse_url($base_url);
 719      $http_protocol = $parts['scheme'];
 720      if (!isset($parts['path'])) {
 721        $parts['path'] = '';
 722      }
 723      $base_path = $parts['path'] . '/';
 724      // Build $base_root (everything until first slash after "scheme://").
 725      $base_root = substr($base_url, 0, strlen($base_url) - strlen($parts['path']));
 726    }
 727    else {
 728      // Create base URL.
 729      $http_protocol = $is_https ? 'https' : 'http';
 730      $base_root = $http_protocol . '://' . $_SERVER['HTTP_HOST'];
 731  
 732      $base_url = $base_root;
 733  
 734      // $_SERVER['SCRIPT_NAME'] can, in contrast to $_SERVER['PHP_SELF'], not
 735      // be modified by a visitor.
 736      if ($dir = rtrim(dirname($_SERVER['SCRIPT_NAME']), '\/')) {
 737        $base_path = $dir;
 738        $base_url .= $base_path;
 739        $base_path .= '/';
 740      }
 741      else {
 742        $base_path = '/';
 743      }
 744    }
 745    $base_secure_url = str_replace('http://', 'https://', $base_url);
 746    $base_insecure_url = str_replace('https://', 'http://', $base_url);
 747  
 748    if ($cookie_domain) {
 749      // If the user specifies the cookie domain, also use it for session name.
 750      $session_name = $cookie_domain;
 751    }
 752    else {
 753      // Otherwise use $base_url as session name, without the protocol
 754      // to use the same session identifiers across HTTP and HTTPS.
 755      list( , $session_name) = explode('://', $base_url, 2);
 756      // HTTP_HOST can be modified by a visitor, but we already sanitized it
 757      // in drupal_settings_initialize().
 758      if (!empty($_SERVER['HTTP_HOST'])) {
 759        $cookie_domain = $_SERVER['HTTP_HOST'];
 760        // Strip leading periods, www., and port numbers from cookie domain.
 761        $cookie_domain = ltrim($cookie_domain, '.');
 762        if (strpos($cookie_domain, 'www.') === 0) {
 763          $cookie_domain = substr($cookie_domain, 4);
 764        }
 765        $cookie_domain = explode(':', $cookie_domain);
 766        $cookie_domain = '.' . $cookie_domain[0];
 767      }
 768    }
 769    // Per RFC 2109, cookie domains must contain at least one dot other than the
 770    // first. For hosts such as 'localhost' or IP Addresses we don't set a cookie domain.
 771    if (count(explode('.', $cookie_domain)) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
 772      ini_set('session.cookie_domain', $cookie_domain);
 773    }
 774    // To prevent session cookies from being hijacked, a user can configure the
 775    // SSL version of their website to only transfer session cookies via SSL by
 776    // using PHP's session.cookie_secure setting. The browser will then use two
 777    // separate session cookies for the HTTPS and HTTP versions of the site. So we
 778    // must use different session identifiers for HTTPS and HTTP to prevent a
 779    // cookie collision.
 780    if ($is_https) {
 781      ini_set('session.cookie_secure', TRUE);
 782    }
 783    $prefix = ini_get('session.cookie_secure') ? 'SSESS' : 'SESS';
 784    session_name($prefix . substr(hash('sha256', $session_name), 0, 32));
 785  }
 786  
 787  /**
 788   * Returns and optionally sets the filename for a system resource.
 789   *
 790   * The filename, whether provided, cached, or retrieved from the database, is
 791   * only returned if the file exists.
 792   *
 793   * This function plays a key role in allowing Drupal's resources (modules
 794   * and themes) to be located in different places depending on a site's
 795   * configuration. For example, a module 'foo' may legally be be located
 796   * in any of these three places:
 797   *
 798   * modules/foo/foo.module
 799   * sites/all/modules/foo/foo.module
 800   * sites/example.com/modules/foo/foo.module
 801   *
 802   * Calling drupal_get_filename('module', 'foo') will give you one of
 803   * the above, depending on where the module is located.
 804   *
 805   * @param $type
 806   *   The type of the item (i.e. theme, theme_engine, module, profile).
 807   * @param $name
 808   *   The name of the item for which the filename is requested.
 809   * @param $filename
 810   *   The filename of the item if it is to be set explicitly rather
 811   *   than by consulting the database.
 812   *
 813   * @return
 814   *   The filename of the requested item.
 815   */
 816  function drupal_get_filename($type, $name, $filename = NULL) {
 817    // The location of files will not change during the request, so do not use
 818    // drupal_static().
 819    static $files = array(), $dirs = array();
 820  
 821    // Profiles are a special case: they have a fixed location and naming.
 822    if ($type == 'profile') {
 823      $profile_filename = "profiles/$name/$name.profile";
 824      $files[$type][$name] = file_exists($profile_filename) ? $profile_filename : FALSE;
 825    }
 826    if (!isset($files[$type])) {
 827      $files[$type] = array();
 828    }
 829  
 830    if (!empty($filename) && file_exists($filename)) {
 831      $files[$type][$name] = $filename;
 832    }
 833    elseif (isset($files[$type][$name])) {
 834      // nothing
 835    }
 836    // Verify that we have an active database connection, before querying
 837    // the database. This is required because this function is called both
 838    // before we have a database connection (i.e. during installation) and
 839    // when a database connection fails.
 840    else {
 841      try {
 842        if (function_exists('db_query')) {
 843          $file = db_query("SELECT filename FROM {system} WHERE name = :name AND type = :type", array(':name' => $name, ':type' => $type))->fetchField();
 844          if (file_exists(DRUPAL_ROOT . '/' . $file)) {
 845            $files[$type][$name] = $file;
 846          }
 847        }
 848      }
 849      catch (Exception $e) {
 850        // The database table may not exist because Drupal is not yet installed,
 851        // or the database might be down. We have a fallback for this case so we
 852        // hide the error completely.
 853      }
 854      // Fallback to searching the filesystem if the database could not find the
 855      // file or the file returned by the database is not found.
 856      if (!isset($files[$type][$name])) {
 857        // We have a consistent directory naming: modules, themes...
 858        $dir = $type . 's';
 859        if ($type == 'theme_engine') {
 860          $dir = 'themes/engines';
 861          $extension = 'engine';
 862        }
 863        elseif ($type == 'theme') {
 864          $extension = 'info';
 865        }
 866        else {
 867          $extension = $type;
 868        }
 869  
 870        if (!isset($dirs[$dir][$extension])) {
 871          $dirs[$dir][$extension] = TRUE;
 872          if (!function_exists('drupal_system_listing')) {
 873            require_once  DRUPAL_ROOT . '/includes/common.inc';
 874          }
 875          // Scan the appropriate directories for all files with the requested
 876          // extension, not just the file we are currently looking for. This
 877          // prevents unnecessary scans from being repeated when this function is
 878          // called more than once in the same page request.
 879          $matches = drupal_system_listing("/^" . DRUPAL_PHP_FUNCTION_PATTERN . "\.$extension$/", $dir, 'name', 0);
 880          foreach ($matches as $matched_name => $file) {
 881            $files[$type][$matched_name] = $file->uri;
 882          }
 883        }
 884      }
 885    }
 886  
 887    if (isset($files[$type][$name])) {
 888      return $files[$type][$name];
 889    }
 890  }
 891  
 892  /**
 893   * Loads the persistent variable table.
 894   *
 895   * The variable table is composed of values that have been saved in the table
 896   * with variable_set() as well as those explicitly specified in the
 897   * configuration file.
 898   */
 899  function variable_initialize($conf = array()) {
 900    // NOTE: caching the variables improves performance by 20% when serving
 901    // cached pages.
 902    if ($cached = cache_get('variables', 'cache_bootstrap')) {
 903      $variables = $cached->data;
 904    }
 905    else {
 906      // Cache miss. Avoid a stampede.
 907      $name = 'variable_init';
 908      if (!lock_acquire($name, 1)) {
 909        // Another request is building the variable cache.
 910        // Wait, then re-run this function.
 911        lock_wait($name);
 912        return variable_initialize($conf);
 913      }
 914      else {
 915        // Proceed with variable rebuild.
 916        $variables = array_map('unserialize', db_query('SELECT name, value FROM {variable}')->fetchAllKeyed());
 917        cache_set('variables', $variables, 'cache_bootstrap');
 918        lock_release($name);
 919      }
 920    }
 921  
 922    foreach ($conf as $name => $value) {
 923      $variables[$name] = $value;
 924    }
 925  
 926    return $variables;
 927  }
 928  
 929  /**
 930   * Returns a persistent variable.
 931   *
 932   * Case-sensitivity of the variable_* functions depends on the database
 933   * collation used. To avoid problems, always use lower case for persistent
 934   * variable names.
 935   *
 936   * @param $name
 937   *   The name of the variable to return.
 938   * @param $default
 939   *   The default value to use if this variable has never been set.
 940   *
 941   * @return
 942   *   The value of the variable. Unserialization is taken care of as necessary.
 943   *
 944   * @see variable_del()
 945   * @see variable_set()
 946   */
 947  function variable_get($name, $default = NULL) {
 948    global $conf;
 949  
 950    return isset($conf[$name]) ? $conf[$name] : $default;
 951  }
 952  
 953  /**
 954   * Sets a persistent variable.
 955   *
 956   * Case-sensitivity of the variable_* functions depends on the database
 957   * collation used. To avoid problems, always use lower case for persistent
 958   * variable names.
 959   *
 960   * @param $name
 961   *   The name of the variable to set.
 962   * @param $value
 963   *   The value to set. This can be any PHP data type; these functions take care
 964   *   of serialization as necessary.
 965   *
 966   * @see variable_del()
 967   * @see variable_get()
 968   */
 969  function variable_set($name, $value) {
 970    global $conf;
 971  
 972    db_merge('variable')->key(array('name' => $name))->fields(array('value' => serialize($value)))->execute();
 973  
 974    cache_clear_all('variables', 'cache_bootstrap');
 975  
 976    $conf[$name] = $value;
 977  }
 978  
 979  /**
 980   * Unsets a persistent variable.
 981   *
 982   * Case-sensitivity of the variable_* functions depends on the database
 983   * collation used. To avoid problems, always use lower case for persistent
 984   * variable names.
 985   *
 986   * @param $name
 987   *   The name of the variable to undefine.
 988   *
 989   * @see variable_get()
 990   * @see variable_set()
 991   */
 992  function variable_del($name) {
 993    global $conf;
 994  
 995    db_delete('variable')
 996      ->condition('name', $name)
 997      ->execute();
 998    cache_clear_all('variables', 'cache_bootstrap');
 999  
1000    unset($conf[$name]);
1001  }
1002  
1003  /**
1004   * Retrieves the current page from the cache.
1005   *
1006   * Note: we do not serve cached pages to authenticated users, or to anonymous
1007   * users when $_SESSION is non-empty. $_SESSION may contain status messages
1008   * from a form submission, the contents of a shopping cart, or other user-
1009   * specific content that should not be cached and displayed to other users.
1010   *
1011   * @param $check_only
1012   *   (optional) Set to TRUE to only return whether a previous call found a
1013   *   cache entry.
1014   *
1015   * @return
1016   *   The cache object, if the page was found in the cache, NULL otherwise.
1017   */
1018  function drupal_page_get_cache($check_only = FALSE) {
1019    global $base_root;
1020    static $cache_hit = FALSE;
1021  
1022    if ($check_only) {
1023      return $cache_hit;
1024    }
1025  
1026    if (drupal_page_is_cacheable()) {
1027      $cache = cache_get($base_root . request_uri(), 'cache_page');
1028      if ($cache !== FALSE) {
1029        $cache_hit = TRUE;
1030      }
1031      return $cache;
1032    }
1033  }
1034  
1035  /**
1036   * Determines the cacheability of the current page.
1037   *
1038   * @param $allow_caching
1039   *   Set to FALSE if you want to prevent this page to get cached.
1040   *
1041   * @return
1042   *   TRUE if the current page can be cached, FALSE otherwise.
1043   */
1044  function drupal_page_is_cacheable($allow_caching = NULL) {
1045    $allow_caching_static = &drupal_static(__FUNCTION__, TRUE);
1046    if (isset($allow_caching)) {
1047      $allow_caching_static = $allow_caching;
1048    }
1049  
1050    return $allow_caching_static && ($_SERVER['REQUEST_METHOD'] == 'GET' || $_SERVER['REQUEST_METHOD'] == 'HEAD')
1051      && !drupal_is_cli();
1052  }
1053  
1054  /**
1055   * Invokes a bootstrap hook in all bootstrap modules that implement it.
1056   *
1057   * @param $hook
1058   *   The name of the bootstrap hook to invoke.
1059   *
1060   * @see bootstrap_hooks()
1061   */
1062  function bootstrap_invoke_all($hook) {
1063    // Bootstrap modules should have been loaded when this function is called, so
1064    // we don't need to tell module_list() to reset its internal list (and we
1065    // therefore leave the first parameter at its default value of FALSE). We
1066    // still pass in TRUE for the second parameter, though; in case this is the
1067    // first time during the bootstrap that module_list() is called, we want to
1068    // make sure that its internal cache is primed with the bootstrap modules
1069    // only.
1070    foreach (module_list(FALSE, TRUE) as $module) {
1071      drupal_load('module', $module);
1072      module_invoke($module, $hook);
1073    }
1074  }
1075  
1076  /**
1077   * Includes a file with the provided type and name.
1078   *
1079   * This prevents including a theme, engine, module, etc., more than once.
1080   *
1081   * @param $type
1082   *   The type of item to load (i.e. theme, theme_engine, module).
1083   * @param $name
1084   *   The name of the item to load.
1085   *
1086   * @return
1087   *   TRUE if the item is loaded or has already been loaded.
1088   */
1089  function drupal_load($type, $name) {
1090    // Once a file is included this can't be reversed during a request so do not
1091    // use drupal_static() here.
1092    static $files = array();
1093  
1094    if (isset($files[$type][$name])) {
1095      return TRUE;
1096    }
1097  
1098    $filename = drupal_get_filename($type, $name);
1099  
1100    if ($filename) {
1101      include_once DRUPAL_ROOT . '/' . $filename;
1102      $files[$type][$name] = TRUE;
1103  
1104      return TRUE;
1105    }
1106  
1107    return FALSE;
1108  }
1109  
1110  /**
1111   * Sets an HTTP response header for the current page.
1112   *
1113   * Note: When sending a Content-Type header, always include a 'charset' type,
1114   * too. This is necessary to avoid security bugs (e.g. UTF-7 XSS).
1115   *
1116   * @param $name
1117   *   The HTTP header name, or the special 'Status' header name.
1118   * @param $value
1119   *   The HTTP header value; if equal to FALSE, the specified header is unset.
1120   *   If $name is 'Status', this is expected to be a status code followed by a
1121   *   reason phrase, e.g. "404 Not Found".
1122   * @param $append
1123   *   Whether to append the value to an existing header or to replace it.
1124   */
1125  function drupal_add_http_header($name, $value, $append = FALSE) {
1126    // The headers as name/value pairs.
1127    $headers = &drupal_static('drupal_http_headers', array());
1128  
1129    $name_lower = strtolower($name);
1130    _drupal_set_preferred_header_name($name);
1131  
1132    if ($value === FALSE) {
1133      $headers[$name_lower] = FALSE;
1134    }
1135    elseif (isset($headers[$name_lower]) && $append) {
1136      // Multiple headers with identical names may be combined using comma (RFC
1137      // 2616, section 4.2).
1138      $headers[$name_lower] .= ',' . $value;
1139    }
1140    else {
1141      $headers[$name_lower] = $value;
1142    }
1143    drupal_send_headers(array($name => $headers[$name_lower]), TRUE);
1144  }
1145  
1146  /**
1147   * Gets the HTTP response headers for the current page.
1148   *
1149   * @param $name
1150   *   An HTTP header name. If omitted, all headers are returned as name/value
1151   *   pairs. If an array value is FALSE, the header has been unset.
1152   *
1153   * @return
1154   *   A string containing the header value, or FALSE if the header has been set,
1155   *   or NULL if the header has not been set.
1156   */
1157  function drupal_get_http_header($name = NULL) {
1158    $headers = &drupal_static('drupal_http_headers', array());
1159    if (isset($name)) {
1160      $name = strtolower($name);
1161      return isset($headers[$name]) ? $headers[$name] : NULL;
1162    }
1163    else {
1164      return $headers;
1165    }
1166  }
1167  
1168  /**
1169   * Sets the preferred name for the HTTP header.
1170   *
1171   * Header names are case-insensitive, but for maximum compatibility they should
1172   * follow "common form" (see RFC 2617, section 4.2).
1173   */
1174  function _drupal_set_preferred_header_name($name = NULL) {
1175    static $header_names = array();
1176  
1177    if (!isset($name)) {
1178      return $header_names;
1179    }
1180    $header_names[strtolower($name)] = $name;
1181  }
1182  
1183  /**
1184   * Sends the HTTP response headers that were previously set, adding defaults.
1185   *
1186   * Headers are set in drupal_add_http_header(). Default headers are not set
1187   * if they have been replaced or unset using drupal_add_http_header().
1188   *
1189   * @param $default_headers
1190   *   An array of headers as name/value pairs.
1191   * @param $single
1192   *   If TRUE and headers have already be sent, send only the specified header.
1193   */
1194  function drupal_send_headers($default_headers = array(), $only_default = FALSE) {
1195    $headers_sent = &drupal_static(__FUNCTION__, FALSE);
1196    $headers = drupal_get_http_header();
1197    if ($only_default && $headers_sent) {
1198      $headers = array();
1199    }
1200    $headers_sent = TRUE;
1201  
1202    $header_names = _drupal_set_preferred_header_name();
1203    foreach ($default_headers as $name => $value) {
1204      $name_lower = strtolower($name);
1205      if (!isset($headers[$name_lower])) {
1206        $headers[$name_lower] = $value;
1207        $header_names[$name_lower] = $name;
1208      }
1209    }
1210    foreach ($headers as $name_lower => $value) {
1211      if ($name_lower == 'status') {
1212        header($_SERVER['SERVER_PROTOCOL'] . ' ' . $value);
1213      }
1214      // Skip headers that have been unset.
1215      elseif ($value) {
1216        header($header_names[$name_lower] . ': ' . $value);
1217      }
1218    }
1219  }
1220  
1221  /**
1222   * Sets HTTP headers in preparation for a page response.
1223   *
1224   * Authenticated users are always given a 'no-cache' header, and will fetch a
1225   * fresh page on every request. This prevents authenticated users from seeing
1226   * locally cached pages.
1227   *
1228   * Also give each page a unique ETag. This will force clients to include both
1229   * an If-Modified-Since header and an If-None-Match header when doing
1230   * conditional requests for the page (required by RFC 2616, section 13.3.4),
1231   * making the validation more robust. This is a workaround for a bug in Mozilla
1232   * Firefox that is triggered when Drupal's caching is enabled and the user
1233   * accesses Drupal via an HTTP proxy (see
1234   * https://bugzilla.mozilla.org/show_bug.cgi?id=269303): When an authenticated
1235   * user requests a page, and then logs out and requests the same page again,
1236   * Firefox may send a conditional request based on the page that was cached
1237   * locally when the user was logged in. If this page did not have an ETag
1238   * header, the request only contains an If-Modified-Since header. The date will
1239   * be recent, because with authenticated users the Last-Modified header always
1240   * refers to the time of the request. If the user accesses Drupal via a proxy
1241   * server, and the proxy already has a cached copy of the anonymous page with an
1242   * older Last-Modified date, the proxy may respond with 304 Not Modified, making
1243   * the client think that the anonymous and authenticated pageviews are
1244   * identical.
1245   *
1246   * @see drupal_page_set_cache()
1247   */
1248  function drupal_page_header() {
1249    $headers_sent = &drupal_static(__FUNCTION__, FALSE);
1250    if ($headers_sent) {
1251      return TRUE;
1252    }
1253    $headers_sent = TRUE;
1254  
1255    $default_headers = array(
1256      'Expires' => 'Sun, 19 Nov 1978 05:00:00 GMT',
1257      'Last-Modified' => gmdate(DATE_RFC1123, REQUEST_TIME),
1258      'Cache-Control' => 'no-cache, must-revalidate, post-check=0, pre-check=0',
1259      'ETag' => '"' . REQUEST_TIME . '"',
1260    );
1261    drupal_send_headers($default_headers);
1262  }
1263  
1264  /**
1265   * Sets HTTP headers in preparation for a cached page response.
1266   *
1267   * The headers allow as much as possible in proxies and browsers without any
1268   * particular knowledge about the pages. Modules can override these headers
1269   * using drupal_add_http_header().
1270   *
1271   * If the request is conditional (using If-Modified-Since and If-None-Match),
1272   * and the conditions match those currently in the cache, a 304 Not Modified
1273   * response is sent.
1274   */
1275  function drupal_serve_page_from_cache(stdClass $cache) {
1276    // Negotiate whether to use compression.
1277    $page_compression = variable_get('page_compression', TRUE) && extension_loaded('zlib');
1278    $return_compressed = $page_compression && isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE;
1279  
1280    // Get headers set in hook_boot(). Keys are lower-case.
1281    $hook_boot_headers = drupal_get_http_header();
1282  
1283    // Headers generated in this function, that may be replaced or unset using
1284    // drupal_add_http_headers(). Keys are mixed-case.
1285    $default_headers = array();
1286  
1287    foreach ($cache->data['headers'] as $name => $value) {
1288      // In the case of a 304 response, certain headers must be sent, and the
1289      // remaining may not (see RFC 2616, section 10.3.5). Do not override
1290      // headers set in hook_boot().
1291      $name_lower = strtolower($name);
1292      if (in_array($name_lower, array('content-location', 'expires', 'cache-control', 'vary')) && !isset($hook_boot_headers[$name_lower])) {
1293        drupal_add_http_header($name, $value);
1294        unset($cache->data['headers'][$name]);
1295      }
1296    }
1297  
1298    // If the client sent a session cookie, a cached copy will only be served
1299    // to that one particular client due to Vary: Cookie. Thus, do not set
1300    // max-age > 0, allowing the page to be cached by external proxies, when a
1301    // session cookie is present unless the Vary header has been replaced or
1302    // unset in hook_boot().
1303    $max_age = !isset($_COOKIE[session_name()]) || isset($hook_boot_headers['vary']) ? variable_get('page_cache_maximum_age', 0) : 0;
1304    $default_headers['Cache-Control'] = 'public, max-age=' . $max_age;
1305  
1306    // Entity tag should change if the output changes.
1307    $etag = '"' . $cache->created . '-' . intval($return_compressed) . '"';
1308    header('Etag: ' . $etag);
1309  
1310    // See if the client has provided the required HTTP headers.
1311    $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) : FALSE;
1312    $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH']) ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) : FALSE;
1313  
1314    if ($if_modified_since && $if_none_match
1315        && $if_none_match == $etag // etag must match
1316        && $if_modified_since == $cache->created) {  // if-modified-since must match
1317      header($_SERVER['SERVER_PROTOCOL'] . ' 304 Not Modified');
1318      drupal_send_headers($default_headers);
1319      return;
1320    }
1321  
1322    // Send the remaining headers.
1323    foreach ($cache->data['headers'] as $name => $value) {
1324      drupal_add_http_header($name, $value);
1325    }
1326  
1327    $default_headers['Last-Modified'] = gmdate(DATE_RFC1123, $cache->created);
1328  
1329    // HTTP/1.0 proxies does not support the Vary header, so prevent any caching
1330    // by sending an Expires date in the past. HTTP/1.1 clients ignores the
1331    // Expires header if a Cache-Control: max-age= directive is specified (see RFC
1332    // 2616, section 14.9.3).
1333    $default_headers['Expires'] = 'Sun, 19 Nov 1978 05:00:00 GMT';
1334  
1335    drupal_send_headers($default_headers);
1336  
1337    // Allow HTTP proxies to cache pages for anonymous users without a session
1338    // cookie. The Vary header is used to indicates the set of request-header
1339    // fields that fully determines whether a cache is permitted to use the
1340    // response to reply to a subsequent request for a given URL without
1341    // revalidation. If a Vary header has been set in hook_boot(), it is assumed
1342    // that the module knows how to cache the page.
1343    if (!isset($hook_boot_headers['vary']) && !variable_get('omit_vary_cookie')) {
1344      header('Vary: Cookie');
1345    }
1346  
1347    if ($page_compression) {
1348      header('Vary: Accept-Encoding', FALSE);
1349      // If page_compression is enabled, the cache contains gzipped data.
1350      if ($return_compressed) {
1351        // $cache->data['body'] is already gzip'ed, so make sure
1352        // zlib.output_compression does not compress it once more.
1353        ini_set('zlib.output_compression', '0');
1354        header('Content-Encoding: gzip');
1355      }
1356      else {
1357        // The client does not support compression, so unzip the data in the
1358        // cache. Strip the gzip header and run uncompress.
1359        $cache->data['body'] = gzinflate(substr(substr($cache->data['body'], 10), 0, -8));
1360      }
1361    }
1362  
1363    // Print the page.
1364    print $cache->data['body'];
1365  }
1366  
1367  /**
1368   * Defines the critical hooks that force modules to always be loaded.
1369   */
1370  function bootstrap_hooks() {
1371    return array('boot', 'exit', 'watchdog', 'language_init');
1372  }
1373  
1374  /**
1375   * Unserializes and appends elements from a serialized string.
1376   *
1377   * @param $obj
1378   *   The object to which the elements are appended.
1379   * @param $field
1380   *   The attribute of $obj whose value should be unserialized.
1381   */
1382  function drupal_unpack($obj, $field = 'data') {
1383    if ($obj->$field && $data = unserialize($obj->$field)) {
1384      foreach ($data as $key => $value) {
1385        if (!empty($key) && !isset($obj->$key)) {
1386          $obj->$key = $value;
1387        }
1388      }
1389    }
1390    return $obj;
1391  }
1392  
1393  /**
1394   * Translates a string to the current language or to a given language.
1395   *
1396   * The t() function serves two purposes. First, at run-time it translates
1397   * user-visible text into the appropriate language. Second, various mechanisms
1398   * that figure out what text needs to be translated work off t() -- the text
1399   * inside t() calls is added to the database of strings to be translated.
1400   * These strings are expected to be in English, so the first argument should
1401   * always be in English. To enable a fully-translatable site, it is important
1402   * that all human-readable text that will be displayed on the site or sent to
1403   * a user is passed through the t() function, or a related function. See the
1404   * @link http://drupal.org/node/322729 Localization API @endlink pages for
1405   * more information, including recommendations on how to break up or not
1406   * break up strings for translation.
1407   *
1408   * You should never use t() to translate variables, such as calling
1409   * @code t($text); @endcode, unless the text that the variable holds has been
1410   * passed through t() elsewhere (e.g., $text is one of several translated
1411   * literal strings in an array). It is especially important never to call
1412   * @code t($user_text); @endcode, where $user_text is some text that a user
1413   * entered - doing that can lead to cross-site scripting and other security
1414   * problems. However, you can use variable substitution in your string, to put
1415   * variable text such as user names or link URLs into translated text. Variable
1416   * substitution looks like this:
1417   * @code
1418   * $text = t("@name's blog", array('@name' => format_username($account)));
1419   * @endcode
1420   * Basically, you can put variables like @name into your string, and t() will
1421   * substitute their sanitized values at translation time. (See the
1422   * Localization API pages referenced above and the documentation of
1423   * format_string() for details.) Translators can then rearrange the string as
1424   * necessary for the language (e.g., in Spanish, it might be "blog de @name").
1425   *
1426   * During the Drupal installation phase, some resources used by t() wil not be
1427   * available to code that needs localization. See st() and get_t() for
1428   * alternatives.
1429   *
1430   * @param $string
1431   *   A string containing the English string to translate.
1432   * @param $args
1433   *   An associative array of replacements to make after translation. Based
1434   *   on the first character of the key, the value is escaped and/or themed.
1435   *   See format_string() for details.
1436   * @param $options
1437   *   An associative array of additional options, with the following elements:
1438   *   - 'langcode' (defaults to the current language): The language code to
1439   *     translate to a language other than what is used to display the page.
1440   *   - 'context' (defaults to the empty context): The context the source string
1441   *     belongs to.
1442   *
1443   * @return
1444   *   The translated string.
1445   *
1446   * @see st()
1447   * @see get_t()
1448   * @see format_string()
1449   * @ingroup sanitization
1450   */
1451  function t($string, array $args = array(), array $options = array()) {
1452    global $language;
1453    static $custom_strings;
1454  
1455    // Merge in default.
1456    if (empty($options['langcode'])) {
1457      $options['langcode'] = isset($language->language) ? $language->language : 'en';
1458    }
1459    if (empty($options['context'])) {
1460      $options['context'] = '';
1461    }
1462  
1463    // First, check for an array of customized strings. If present, use the array
1464    // *instead of* database lookups. This is a high performance way to provide a
1465    // handful of string replacements. See settings.php for examples.
1466    // Cache the $custom_strings variable to improve performance.
1467    if (!isset($custom_strings[$options['langcode']])) {
1468      $custom_strings[$options['langcode']] = variable_get('locale_custom_strings_' . $options['langcode'], array());
1469    }
1470    // Custom strings work for English too, even if locale module is disabled.
1471    if (isset($custom_strings[$options['langcode']][$options['context']][$string])) {
1472      $string = $custom_strings[$options['langcode']][$options['context']][$string];
1473    }
1474    // Translate with locale module if enabled.
1475    elseif ($options['langcode'] != 'en' && function_exists('locale')) {
1476      $string = locale($string, $options['context'], $options['langcode']);
1477    }
1478    if (empty($args)) {
1479      return $string;
1480    }
1481    else {
1482      return format_string($string, $args);
1483    }
1484  }
1485  
1486  /**
1487   * Replaces placeholders with sanitized values in a string.
1488   *
1489   * @param $string
1490   *   A string containing placeholders.
1491   * @param $args
1492   *   An associative array of replacements to make. Occurrences in $string of
1493   *   any key in $args are replaced with the corresponding value, after
1494   *   sanitization. The sanitization function depends on the first character of
1495   *   the key:
1496   *   - !variable: Inserted as is. Use this for text that has already been
1497   *     sanitized.
1498   *   - @variable: Escaped to HTML using check_plain(). Use this for anything
1499   *     displayed on a page on the site.
1500   *   - %variable: Escaped as a placeholder for user-submitted content using
1501   *     drupal_placeholder(), which shows up as <em>emphasized</em> text.
1502   *
1503   * @see t()
1504   * @ingroup sanitization
1505   */
1506  function format_string($string, array $args = array()) {
1507    // Transform arguments before inserting them.
1508    foreach ($args as $key => $value) {
1509      switch ($key[0]) {
1510        case '@':
1511          // Escaped only.
1512          $args[$key] = check_plain($value);
1513          break;
1514  
1515        case '%':
1516        default:
1517          // Escaped and placeholder.
1518          $args[$key] = drupal_placeholder($value);
1519          break;
1520  
1521        case '!':
1522          // Pass-through.
1523      }
1524    }
1525    return strtr($string, $args);
1526  }
1527  
1528  /**
1529   * Encodes special characters in a plain-text string for display as HTML.
1530   *
1531   * Also validates strings as UTF-8 to prevent cross site scripting attacks on
1532   * Internet Explorer 6.
1533   *
1534   * @param $text
1535   *   The text to be checked or processed.
1536   *
1537   * @return
1538   *   An HTML safe version of $text, or an empty string if $text is not
1539   *   valid UTF-8.
1540   *
1541   * @see drupal_validate_utf8()
1542   * @ingroup sanitization
1543   */
1544  function check_plain($text) {
1545    return htmlspecialchars($text, ENT_QUOTES, 'UTF-8');
1546  }
1547  
1548  /**
1549   * Checks whether a string is valid UTF-8.
1550   *
1551   * All functions designed to filter input should use drupal_validate_utf8
1552   * to ensure they operate on valid UTF-8 strings to prevent bypass of the
1553   * filter.
1554   *
1555   * When text containing an invalid UTF-8 lead byte (0xC0 - 0xFF) is presented
1556   * as UTF-8 to Internet Explorer 6, the program may misinterpret subsequent
1557   * bytes. When these subsequent bytes are HTML control characters such as
1558   * quotes or angle brackets, parts of the text that were deemed safe by filters
1559   * end up in locations that are potentially unsafe; An onerror attribute that
1560   * is outside of a tag, and thus deemed safe by a filter, can be interpreted
1561   * by the browser as if it were inside the tag.
1562   *
1563   * The function does not return FALSE for strings containing character codes
1564   * above U+10FFFF, even though these are prohibited by RFC 3629.
1565   *
1566   * @param $text
1567   *   The text to check.
1568   *
1569   * @return
1570   *   TRUE if the text is valid UTF-8, FALSE if not.
1571   */
1572  function drupal_validate_utf8($text) {
1573    if (strlen($text) == 0) {
1574      return TRUE;
1575    }
1576    // With the PCRE_UTF8 modifier 'u', preg_match() fails silently on strings
1577    // containing invalid UTF-8 byte sequences. It does not reject character
1578    // codes above U+10FFFF (represented by 4 or more octets), though.
1579    return (preg_match('/^./us', $text) == 1);
1580  }
1581  
1582  /**
1583   * Returns the equivalent of Apache's $_SERVER['REQUEST_URI'] variable.
1584   *
1585   * Because $_SERVER['REQUEST_URI'] is only available on Apache, we generate an
1586   * equivalent using other environment variables.
1587   */
1588  function request_uri() {
1589    if (isset($_SERVER['REQUEST_URI'])) {
1590      $uri = $_SERVER['REQUEST_URI'];
1591    }
1592    else {
1593      if (isset($_SERVER['argv'])) {
1594        $uri = $_SERVER['SCRIPT_NAME'] . '?' . $_SERVER['argv'][0];
1595      }
1596      elseif (isset($_SERVER['QUERY_STRING'])) {
1597        $uri = $_SERVER['SCRIPT_NAME'] . '?' . $_SERVER['QUERY_STRING'];
1598      }
1599      else {
1600        $uri = $_SERVER['SCRIPT_NAME'];
1601      }
1602    }
1603    // Prevent multiple slashes to avoid cross site requests via the Form API.
1604    $uri = '/' . ltrim($uri, '/');
1605  
1606    return $uri;
1607  }
1608  
1609  /**
1610   * Logs an exception.
1611   *
1612   * This is a wrapper function for watchdog() which automatically decodes an
1613   * exception.
1614   *
1615   * @param $type
1616   *   The category to which this message belongs.
1617   * @param $exception
1618   *   The exception that is going to be logged.
1619   * @param $message
1620   *   The message to store in the log. If empty, a text that contains all useful
1621   *   information about the passed-in exception is used.
1622   * @param $variables
1623   *   Array of variables to replace in the message on display. Defaults to the
1624   *   return value of drupal_decode_exception().
1625   * @param $severity
1626   *   The severity of the message, as per RFC 3164.
1627   * @param $link
1628   *   A link to associate with the message.
1629   *
1630   * @see watchdog()
1631   * @see drupal_decode_exception()
1632   */
1633  function watchdog_exception($type, Exception $exception, $message = NULL, $variables = array(), $severity = WATCHDOG_ERROR, $link = NULL) {
1634  
1635     // Use a default value if $message is not set.
1636     if (empty($message)) {
1637       // The exception message is run through check_plain() by _drupal_decode_exception().
1638       $message = '%type: !message in %function (line %line of %file).';
1639     }
1640     // $variables must be an array so that we can add the exception information.
1641     if (!is_array($variables)) {
1642       $variables = array();
1643     }
1644  
1645     require_once  DRUPAL_ROOT . '/includes/errors.inc';
1646     $variables += _drupal_decode_exception($exception);
1647     watchdog($type, $message, $variables, $severity, $link);
1648  }
1649  
1650  /**
1651   * Logs a system message.
1652   *
1653   * @param $type
1654   *   The category to which this message belongs. Can be any string, but the
1655   *   general practice is to use the name of the module calling watchdog().
1656   * @param $message
1657   *   The message to store in the log. Keep $message translatable
1658   *   by not concatenating dynamic values into it! Variables in the
1659   *   message should be added by using placeholder strings alongside
1660   *   the variables argument to declare the value of the placeholders.
1661   *   See t() for documentation on how $message and $variables interact.
1662   * @param $variables
1663   *   Array of variables to replace in the message on display or
1664   *   NULL if message is already translated or not possible to
1665   *   translate.
1666   * @param $severity
1667   *   The severity of the message; one of the following values as defined in
1668   *   @link http://www.faqs.org/rfcs/rfc3164.html RFC 3164: @endlink
1669   *   - WATCHDOG_EMERGENCY: Emergency, system is unusable.
1670   *   - WATCHDOG_ALERT: Alert, action must be taken immediately.
1671   *   - WATCHDOG_CRITICAL: Critical conditions.
1672   *   - WATCHDOG_ERROR: Error conditions.
1673   *   - WATCHDOG_WARNING: Warning conditions.
1674   *   - WATCHDOG_NOTICE: (default) Normal but significant conditions.
1675   *   - WATCHDOG_INFO: Informational messages.
1676   *   - WATCHDOG_DEBUG: Debug-level messages.
1677   * @param $link
1678   *   A link to associate with the message.
1679   *
1680   * @see watchdog_severity_levels()
1681   * @see hook_watchdog()
1682   */
1683  function watchdog($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE, $link = NULL) {
1684    global $user, $base_root;
1685  
1686    static $in_error_state = FALSE;
1687  
1688    // It is possible that the error handling will itself trigger an error. In that case, we could
1689    // end up in an infinite loop. To avoid that, we implement a simple static semaphore.
1690    if (!$in_error_state && function_exists('module_implements')) {
1691      $in_error_state = TRUE;
1692  
1693      // The user object may not exist in all conditions, so 0 is substituted if needed.
1694      $user_uid = isset($user->uid) ? $user->uid : 0;
1695  
1696      // Prepare the fields to be logged
1697      $log_entry = array(
1698        'type'        => $type,
1699        'message'     => $message,
1700        'variables'   => $variables,
1701        'severity'    => $severity,
1702        'link'        => $link,
1703        'user'        => $user,
1704        'uid'         => $user_uid,
1705        'request_uri' => $base_root . request_uri(),
1706        'referer'     => isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '',
1707        'ip'          => ip_address(),
1708        // Request time isn't accurate for long processes, use time() instead.
1709        'timestamp'   => time(),
1710      );
1711  
1712      // Call the logging hooks to log/process the message
1713      foreach (module_implements('watchdog') as $module) {
1714        module_invoke($module, 'watchdog', $log_entry);
1715      }
1716  
1717      // It is critical that the semaphore is only cleared here, in the parent
1718      // watchdog() call (not outside the loop), to prevent recursive execution.
1719      $in_error_state = FALSE;
1720    }
1721  }
1722  
1723  /**
1724   * Sets a message to display to the user.
1725   *
1726   * Messages are stored in a session variable and displayed in page.tpl.php via
1727   * the $messages theme variable.
1728   *
1729   * Example usage:
1730   * @code
1731   * drupal_set_message(t('An error occurred and processing did not complete.'), 'error');
1732   * @endcode
1733   *
1734   * @param string $message
1735   *   (optional) The translated message to be displayed to the user. For
1736   *   consistency with other messages, it should begin with a capital letter and
1737   *   end with a period.
1738   * @param string $type
1739   *   (optional) The message's type. Defaults to 'status'. These values are
1740   *   supported:
1741   *   - 'status'
1742   *   - 'warning'
1743   *   - 'error'
1744   * @param bool $repeat
1745   *   (optional) If this is FALSE and the message is already set, then the
1746   *   message won't be repeated. Defaults to TRUE.
1747   *
1748   * @return array|null
1749   *   A multidimensional array with keys corresponding to the set message types.
1750   *   The indexed array values of each contain the set messages for that type.
1751   *   Or, if there are no messages set, the function returns NULL.
1752   *
1753   * @see drupal_get_messages()
1754   * @see theme_status_messages()
1755   */
1756  function drupal_set_message($message = NULL, $type = 'status', $repeat = TRUE) {
1757    if ($message) {
1758      if (!isset($_SESSION['messages'][$type])) {
1759        $_SESSION['messages'][$type] = array();
1760      }
1761  
1762      if ($repeat || !in_array($message, $_SESSION['messages'][$type])) {
1763        $_SESSION['messages'][$type][] = $message;
1764      }
1765  
1766      // Mark this page as being uncacheable.
1767      drupal_page_is_cacheable(FALSE);
1768    }
1769  
1770    // Messages not set when DB connection fails.
1771    return isset($_SESSION['messages']) ? $_SESSION['messages'] : NULL;
1772  }
1773  
1774  /**
1775   * Returns all messages that have been set with drupal_set_message().
1776   *
1777   * @param string $type
1778   *   (optional) Limit the messages returned by type. Defaults to NULL, meaning
1779   *   all types. These values are supported:
1780   *   - NULL
1781   *   - 'status'
1782   *   - 'warning'
1783   *   - 'error'
1784   * @param bool $clear_queue
1785   *   (optional) If this is TRUE, the queue will be cleared of messages of the
1786   *   type specified in the $type parameter. Otherwise the queue will be left
1787   *   intact. Defaults to TRUE.
1788   *
1789   * @return array
1790   *   A multidimensional array with keys corresponding to the set message types.
1791   *   The indexed array values of each contain the set messages for that type.
1792   *   The messages returned are limited to the type specified in the $type
1793   *   parameter. If there are no messages of the specified type, an empty array
1794   *   is returned.
1795   *
1796   * @see drupal_set_message()
1797   * @see theme_status_messages()
1798   */
1799  function drupal_get_messages($type = NULL, $clear_queue = TRUE) {
1800    if ($messages = drupal_set_message()) {
1801      if ($type) {
1802        if ($clear_queue) {
1803          unset($_SESSION['messages'][$type]);
1804        }
1805        if (isset($messages[$type])) {
1806          return array($type => $messages[$type]);
1807        }
1808      }
1809      else {
1810        if ($clear_queue) {
1811          unset($_SESSION['messages']);
1812        }
1813        return $messages;
1814      }
1815    }
1816    return array();
1817  }
1818  
1819  /**
1820   * Gets the title of the current page.
1821   *
1822   * The title is displayed on the page and in the title bar.
1823   *
1824   * @return
1825   *   The current page's title.
1826   */
1827  function drupal_get_title() {
1828    $title = drupal_set_title();
1829  
1830    // During a bootstrap, menu.inc is not included and thus we cannot provide a title.
1831    if (!isset($title) && function_exists('menu_get_active_title')) {
1832      $title = check_plain(menu_get_active_title());
1833    }
1834  
1835    return $title;
1836  }
1837  
1838  /**
1839   * Sets the title of the current page.
1840   *
1841   * The title is displayed on the page and in the title bar.
1842   *
1843   * @param $title
1844   *   Optional string value to assign to the page title; or if set to NULL
1845   *   (default), leaves the current title unchanged.
1846   * @param $output
1847   *   Optional flag - normally should be left as CHECK_PLAIN. Only set to
1848   *   PASS_THROUGH if you have already removed any possibly dangerous code
1849   *   from $title using a function like check_plain() or filter_xss(). With this
1850   *   flag the string will be passed through unchanged.
1851   *
1852   * @return
1853   *   The updated title of the current page.
1854   */
1855  function drupal_set_title($title = NULL, $output = CHECK_PLAIN) {
1856    $stored_title = &drupal_static(__FUNCTION__);
1857  
1858    if (isset($title)) {
1859      $stored_title = ($output == PASS_THROUGH) ? $title : check_plain($title);
1860    }
1861  
1862    return $stored_title;
1863  }
1864  
1865  /**
1866   * Checks to see if an IP address has been blocked.
1867   *
1868   * Blocked IP addresses are stored in the database by default. However for
1869   * performance reasons we allow an override in settings.php. This allows us
1870   * to avoid querying the database at this critical stage of the bootstrap if
1871   * an administrative interface for IP address blocking is not required.
1872   *
1873   * @param $ip
1874   *   IP address to check.
1875   *
1876   * @return bool
1877   *   TRUE if access is denied, FALSE if access is allowed.
1878   */
1879  function drupal_is_denied($ip) {
1880    // Because this function is called on every page request, we first check
1881    // for an array of IP addresses in settings.php before querying the
1882    // database.
1883    $blocked_ips = variable_get('blocked_ips');
1884    $denied = FALSE;
1885    if (isset($blocked_ips) && is_array($blocked_ips)) {
1886      $denied = in_array($ip, $blocked_ips);
1887    }
1888    // Only check if database.inc is loaded already. If
1889    // $conf['page_cache_without_database'] = TRUE; is set in settings.php,
1890    // then the database won't be loaded here so the IPs in the database
1891    // won't be denied. However the user asked explicitly not to use the
1892    // database and also in this case it's quite likely that the user relies
1893    // on higher performance solutions like a firewall.
1894    elseif (class_exists('Database', FALSE)) {
1895      $denied = (bool)db_query("SELECT 1 FROM {blocked_ips} WHERE ip = :ip", array(':ip' => $ip))->fetchField();
1896    }
1897    return $denied;
1898  }
1899  
1900  /**
1901   * Handles denied users.
1902   *
1903   * @param $ip
1904   *   IP address to check. Prints a message and exits if access is denied.
1905   */
1906  function drupal_block_denied($ip) {
1907    // Deny access to blocked IP addresses - t() is not yet available.
1908    if (drupal_is_denied($ip)) {
1909      header($_SERVER['SERVER_PROTOCOL'] . ' 403 Forbidden');
1910      print 'Sorry, ' . check_plain(ip_address()) . ' has been banned.';
1911      exit();
1912    }
1913  }
1914  
1915  /**
1916   * Returns a string of highly randomized bytes (over the full 8-bit range).
1917   *
1918   * This function is better than simply calling mt_rand() or any other built-in
1919   * PHP function because it can return a long string of bytes (compared to < 4
1920   * bytes normally from mt_rand()) and uses the best available pseudo-random
1921   * source.
1922   *
1923   * @param $count
1924   *   The number of characters (bytes) to return in the string.
1925   */
1926  function drupal_random_bytes($count)  {
1927    // $random_state does not use drupal_static as it stores random bytes.
1928    static $random_state, $bytes, $php_compatible;
1929    // Initialize on the first call. The contents of $_SERVER includes a mix of
1930    // user-specific and system information that varies a little with each page.
1931    if (!isset($random_state)) {
1932      $random_state = print_r($_SERVER, TRUE);
1933      if (function_exists('getmypid')) {
1934        // Further initialize with the somewhat random PHP process ID.
1935        $random_state .= getmypid();
1936      }
1937      $bytes = '';
1938    }
1939    if (strlen($bytes) < $count) {
1940      // PHP versions prior 5.3.4 experienced openssl_random_pseudo_bytes()
1941      // locking on Windows and rendered it unusable.
1942      if (!isset($php_compatible)) {
1943        $php_compatible = version_compare(PHP_VERSION, '5.3.4', '>=');
1944      }
1945      // /dev/urandom is available on many *nix systems and is considered the
1946      // best commonly available pseudo-random source.
1947      if ($fh = @fopen('/dev/urandom', 'rb')) {
1948        // PHP only performs buffered reads, so in reality it will always read
1949        // at least 4096 bytes. Thus, it costs nothing extra to read and store
1950        // that much so as to speed any additional invocations.
1951        $bytes .= fread($fh, max(4096, $count));
1952        fclose($fh);
1953      }
1954      // openssl_random_pseudo_bytes() will find entropy in a system-dependent
1955      // way.
1956      elseif ($php_compatible && function_exists('openssl_random_pseudo_bytes')) {
1957        $bytes .= openssl_random_pseudo_bytes($count - strlen($bytes));
1958      }
1959      // If /dev/urandom is not available or returns no bytes, this loop will
1960      // generate a good set of pseudo-random bytes on any system.
1961      // Note that it may be important that our $random_state is passed
1962      // through hash() prior to being rolled into $output, that the two hash()
1963      // invocations are different, and that the extra input into the first one -
1964      // the microtime() - is prepended rather than appended. This is to avoid
1965      // directly leaking $random_state via the $output stream, which could
1966      // allow for trivial prediction of further "random" numbers.
1967      while (strlen($bytes) < $count) {
1968        $random_state = hash('sha256', microtime() . mt_rand() . $random_state);
1969        $bytes .= hash('sha256', mt_rand() . $random_state, TRUE);
1970      }
1971    }
1972    $output = substr($bytes, 0, $count);
1973    $bytes = substr($bytes, $count);
1974    return $output;
1975  }
1976  
1977  /**
1978   * Calculates a base-64 encoded, URL-safe sha-256 hmac.
1979   *
1980   * @param $data
1981   *   String to be validated with the hmac.
1982   * @param $key
1983   *   A secret string key.
1984   *
1985   * @return
1986   *   A base-64 encoded sha-256 hmac, with + replaced with -, / with _ and
1987   *   any = padding characters removed.
1988   */
1989  function drupal_hmac_base64($data, $key) {
1990    $hmac = base64_encode(hash_hmac('sha256', $data, $key, TRUE));
1991    // Modify the hmac so it's safe to use in URLs.
1992    return strtr($hmac, array('+' => '-', '/' => '_', '=' => ''));
1993  }
1994  
1995  /**
1996   * Calculates a base-64 encoded, URL-safe sha-256 hash.
1997   *
1998   * @param $data
1999   *   String to be hashed.
2000   *
2001   * @return
2002   *   A base-64 encoded sha-256 hash, with + replaced with -, / with _ and
2003   *   any = padding characters removed.
2004   */
2005  function drupal_hash_base64($data) {
2006    $hash = base64_encode(hash('sha256', $data, TRUE));
2007    // Modify the hash so it's safe to use in URLs.
2008    return strtr($hash, array('+' => '-', '/' => '_', '=' => ''));
2009  }
2010  
2011  /**
2012   * Merges multiple arrays, recursively, and returns the merged array.
2013   *
2014   * This function is similar to PHP's array_merge_recursive() function, but it
2015   * handles non-array values differently. When merging values that are not both
2016   * arrays, the latter value replaces the former rather than merging with it.
2017   *
2018   * Example:
2019   * @code
2020   * $link_options_1 = array('fragment' => 'x', 'attributes' => array('title' => t('X'), 'class' => array('a', 'b')));
2021   * $link_options_2 = array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('c', 'd')));
2022   *
2023   * // This results in array('fragment' => array('x', 'y'), 'attributes' => array('title' => array(t('X'), t('Y')), 'class' => array('a', 'b', 'c', 'd'))).
2024   * $incorrect = array_merge_recursive($link_options_1, $link_options_2);
2025   *
2026   * // This results in array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('a', 'b', 'c', 'd'))).
2027   * $correct = drupal_array_merge_deep($link_options_1, $link_options_2);
2028   * @endcode
2029   *
2030   * @param ...
2031   *   Arrays to merge.
2032   *
2033   * @return
2034   *   The merged array.
2035   *
2036   * @see drupal_array_merge_deep_array()
2037   */
2038  function drupal_array_merge_deep() {
2039    $args = func_get_args();
2040    return drupal_array_merge_deep_array($args);
2041  }
2042  
2043  /**
2044   * Merges multiple arrays, recursively, and returns the merged array.
2045   *
2046   * This function is equivalent to drupal_array_merge_deep(), except the
2047   * input arrays are passed as a single array parameter rather than a variable
2048   * parameter list.
2049   *
2050   * The following are equivalent:
2051   * - drupal_array_merge_deep($a, $b);
2052   * - drupal_array_merge_deep_array(array($a, $b));
2053   *
2054   * The following are also equivalent:
2055   * - call_user_func_array('drupal_array_merge_deep', $arrays_to_merge);
2056   * - drupal_array_merge_deep_array($arrays_to_merge);
2057   *
2058   * @see drupal_array_merge_deep()
2059   */
2060  function drupal_array_merge_deep_array($arrays) {
2061    $result = array();
2062  
2063    foreach ($arrays as $array) {
2064      foreach ($array as $key => $value) {
2065        // Renumber integer keys as array_merge_recursive() does. Note that PHP
2066        // automatically converts array keys that are integer strings (e.g., '1')
2067        // to integers.
2068        if (is_integer($key)) {
2069          $result[] = $value;
2070        }
2071        // Recurse when both values are arrays.
2072        elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
2073          $result[$key] = drupal_array_merge_deep_array(array($result[$key], $value));
2074        }
2075        // Otherwise, use the latter value, overriding any previous value.
2076        else {
2077          $result[$key] = $value;
2078        }
2079      }
2080    }
2081  
2082    return $result;
2083  }
2084  
2085  /**
2086   * Generates a default anonymous $user object.
2087   *
2088   * @return Object - the user object.
2089   */
2090  function drupal_anonymous_user() {
2091    $user = new stdClass();
2092    $user->uid = 0;
2093    $user->hostname = ip_address();
2094    $user->roles = array();
2095    $user->roles[DRUPAL_ANONYMOUS_RID] = 'anonymous user';
2096    $user->cache = 0;
2097    return $user;
2098  }
2099  
2100  /**
2101   * Ensures Drupal is bootstrapped to the specified phase.
2102   *
2103   * In order to bootstrap Drupal from another PHP script, you can use this code:
2104   * @code
2105   *   define('DRUPAL_ROOT', '/path/to/drupal');
2106   *   require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
2107   *   drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
2108   * @endcode
2109   *
2110   * @param $phase
2111   *   A constant telling which phase to bootstrap to. When you bootstrap to a
2112   *   particular phase, all earlier phases are run automatically. Possible
2113   *   values:
2114   *   - DRUPAL_BOOTSTRAP_CONFIGURATION: Initializes configuration.
2115   *   - DRUPAL_BOOTSTRAP_PAGE_CACHE: Tries to serve a cached page.
2116   *   - DRUPAL_BOOTSTRAP_DATABASE: Initializes the database layer.
2117   *   - DRUPAL_BOOTSTRAP_VARIABLES: Initializes the variable system.
2118   *   - DRUPAL_BOOTSTRAP_SESSION: Initializes session handling.
2119   *   - DRUPAL_BOOTSTRAP_PAGE_HEADER: Sets up the page header.
2120   *   - DRUPAL_BOOTSTRAP_LANGUAGE: Finds out the language of the page.
2121   *   - DRUPAL_BOOTSTRAP_FULL: Fully loads Drupal. Validates and fixes input
2122   *     data.
2123   * @param $new_phase
2124   *   A boolean, set to FALSE if calling drupal_bootstrap from inside a
2125   *   function called from drupal_bootstrap (recursion).
2126   *
2127   * @return
2128   *   The most recently completed phase.
2129   */
2130  function drupal_bootstrap($phase = NULL, $new_phase = TRUE) {
2131    // Not drupal_static(), because does not depend on any run-time information.
2132    static $phases = array(
2133      DRUPAL_BOOTSTRAP_CONFIGURATION,
2134      DRUPAL_BOOTSTRAP_PAGE_CACHE,
2135      DRUPAL_BOOTSTRAP_DATABASE,
2136      DRUPAL_BOOTSTRAP_VARIABLES,
2137      DRUPAL_BOOTSTRAP_SESSION,
2138      DRUPAL_BOOTSTRAP_PAGE_HEADER,
2139      DRUPAL_BOOTSTRAP_LANGUAGE,
2140      DRUPAL_BOOTSTRAP_FULL,
2141    );
2142    // Not drupal_static(), because the only legitimate API to control this is to
2143    // call drupal_bootstrap() with a new phase parameter.
2144    static $final_phase;
2145    // Not drupal_static(), because it's impossible to roll back to an earlier
2146    // bootstrap state.
2147    static $stored_phase = -1;
2148  
2149    // When not recursing, store the phase name so it's not forgotten while
2150    // recursing.
2151    if ($new_phase) {
2152      $final_phase = $phase;
2153    }
2154    if (isset($phase)) {
2155      // Call a phase if it has not been called before and is below the requested
2156      // phase.
2157      while ($phases && $phase > $stored_phase && $final_phase > $stored_phase) {
2158        $current_phase = array_shift($phases);
2159  
2160        // This function is re-entrant. Only update the completed phase when the
2161        // current call actually resulted in a progress in the bootstrap process.
2162        if ($current_phase > $stored_phase) {
2163          $stored_phase = $current_phase;
2164        }
2165  
2166        switch ($current_phase) {
2167          case DRUPAL_BOOTSTRAP_CONFIGURATION:
2168            _drupal_bootstrap_configuration();
2169            break;
2170  
2171          case DRUPAL_BOOTSTRAP_PAGE_CACHE:
2172            _drupal_bootstrap_page_cache();
2173            break;
2174  
2175          case DRUPAL_BOOTSTRAP_DATABASE:
2176            _drupal_bootstrap_database();
2177            break;
2178  
2179          case DRUPAL_BOOTSTRAP_VARIABLES:
2180            _drupal_bootstrap_variables();
2181            break;
2182  
2183          case DRUPAL_BOOTSTRAP_SESSION:
2184            require_once DRUPAL_ROOT . '/' . variable_get('session_inc', 'includes/session.inc');
2185            drupal_session_initialize();
2186            break;
2187  
2188          case DRUPAL_BOOTSTRAP_PAGE_HEADER:
2189            _drupal_bootstrap_page_header();
2190            break;
2191  
2192          case DRUPAL_BOOTSTRAP_LANGUAGE:
2193            drupal_language_initialize();
2194            break;
2195  
2196          case DRUPAL_BOOTSTRAP_FULL:
2197            require_once  DRUPAL_ROOT . '/includes/common.inc';
2198            _drupal_bootstrap_full();
2199            break;
2200        }
2201      }
2202    }
2203    return $stored_phase;
2204  }
2205  
2206  /**
2207   * Returns the time zone of the current user.
2208   */
2209  function drupal_get_user_timezone() {
2210    global $user;
2211    if (variable_get('configurable_timezones', 1) && $user->uid && $user->timezone) {
2212      return $user->timezone;
2213    }
2214    else {
2215      // Ignore PHP strict notice if time zone has not yet been set in the php.ini
2216      // configuration.
2217      return variable_get('date_default_timezone', @date_default_timezone_get());
2218    }
2219  }
2220  
2221  /**
2222   * Provides custom PHP error handling.
2223   *
2224   * @param $error_level
2225   *   The level of the error raised.
2226   * @param $message
2227   *   The error message.
2228   * @param $filename
2229   *   The filename that the error was raised in.
2230   * @param $line
2231   *   The line number the error was raised at.
2232   * @param $context
2233   *   An array that points to the active symbol table at the point the error
2234   *   occurred.
2235   */
2236  function _drupal_error_handler($error_level, $message, $filename, $line, $context) {
2237    require_once  DRUPAL_ROOT . '/includes/errors.inc';
2238    _drupal_error_handler_real($error_level, $message, $filename, $line, $context);
2239  }
2240  
2241  /**
2242   * Provides custom PHP exception handling.
2243   *
2244   * Uncaught exceptions are those not enclosed in a try/catch block. They are
2245   * always fatal: the execution of the script will stop as soon as the exception
2246   * handler exits.
2247   *
2248   * @param $exception
2249   *   The exception object that was thrown.
2250   */
2251  function _drupal_exception_handler($exception) {
2252    require_once  DRUPAL_ROOT . '/includes/errors.inc';
2253  
2254    try {
2255      // Log the message to the watchdog and return an error page to the user.
2256      _drupal_log_error(_drupal_decode_exception($exception), TRUE);
2257    }
2258    catch (Exception $exception2) {
2259      // Another uncaught exception was thrown while handling the first one.
2260      // If we are displaying errors, then do so with no possibility of a further uncaught exception being thrown.
2261      if (error_displayable()) {
2262        print '<h1>Additional uncaught exception thrown while handling exception.</h1>';
2263        print '<h2>Original</h2><p>' . _drupal_render_exception_safe($exception) . '</p>';
2264        print '<h2>Additional</h2><p>' . _drupal_render_exception_safe($exception2) . '</p><hr />';
2265      }
2266    }
2267  }
2268  
2269  /**
2270   * Sets up the script environment and loads settings.php.
2271   */
2272  function _drupal_bootstrap_configuration() {
2273    // Set the Drupal custom error handler.
2274    set_error_handler('_drupal_error_handler');
2275    set_exception_handler('_drupal_exception_handler');
2276  
2277    drupal_environment_initialize();
2278    // Start a page timer:
2279    timer_start('page');
2280    // Initialize the configuration, including variables from settings.php.
2281    drupal_settings_initialize();
2282  }
2283  
2284  /**
2285   * Attempts to serve a page from the cache.
2286   */
2287  function _drupal_bootstrap_page_cache() {
2288    global $user;
2289  
2290    // Allow specifying special cache handlers in settings.php, like
2291    // using memcached or files for storing cache information.
2292    require_once  DRUPAL_ROOT . '/includes/cache.inc';
2293    foreach (variable_get('cache_backends', array()) as $include) {
2294      require_once DRUPAL_ROOT . '/' . $include;
2295    }
2296    // Check for a cache mode force from settings.php.
2297    if (variable_get('page_cache_without_database')) {
2298      $cache_enabled = TRUE;
2299    }
2300    else {
2301      drupal_bootstrap(DRUPAL_BOOTSTRAP_VARIABLES, FALSE);
2302      $cache_enabled = variable_get('cache');
2303    }
2304    drupal_block_denied(ip_address());
2305    // If there is no session cookie and cache is enabled (or forced), try
2306    // to serve a cached page.
2307    if (!isset($_COOKIE[session_name()]) && $cache_enabled) {
2308      // Make sure there is a user object because its timestamp will be
2309      // checked, hook_boot might check for anonymous user etc.
2310      $user = drupal_anonymous_user();
2311      // Get the page from the cache.
2312      $cache = drupal_page_get_cache();
2313      // If there is a cached page, display it.
2314      if (is_object($cache)) {
2315        header('X-Drupal-Cache: HIT');
2316        // Restore the metadata cached with the page.
2317        $_GET['q'] = $cache->data['path'];
2318        drupal_set_title($cache->data['title'], PASS_THROUGH);
2319        date_default_timezone_set(drupal_get_user_timezone());
2320        // If the skipping of the bootstrap hooks is not enforced, call
2321        // hook_boot.
2322        if (variable_get('page_cache_invoke_hooks', TRUE)) {
2323          bootstrap_invoke_all('boot');
2324        }
2325        drupal_serve_page_from_cache($cache);
2326        // If the skipping of the bootstrap hooks is not enforced, call
2327        // hook_exit.
2328        if (variable_get('page_cache_invoke_hooks', TRUE)) {
2329          bootstrap_invoke_all('exit');
2330        }
2331        // We are done.
2332        exit;
2333      }
2334      else {
2335        header('X-Drupal-Cache: MISS');
2336      }
2337    }
2338  }
2339  
2340  /**
2341   * Initializes the database system and registers autoload functions.
2342   */
2343  function _drupal_bootstrap_database() {
2344    // Redirect the user to the installation script if Drupal has not been
2345    // installed yet (i.e., if no $databases array has been defined in the
2346    // settings.php file) and we are not already installing.
2347    if (empty($GLOBALS['databases']) && !drupal_installation_attempted()) {
2348      include_once  DRUPAL_ROOT . '/includes/install.inc';
2349      install_goto('install.php');
2350    }
2351  
2352    // The user agent header is used to pass a database prefix in the request when
2353    // running tests. However, for security reasons, it is imperative that we
2354    // validate we ourselves made the request.
2355    if ($test_prefix = drupal_valid_test_ua()) {
2356      // Set the test run id for use in other parts of Drupal.
2357      $test_info = &$GLOBALS['drupal_test_info'];
2358      $test_info['test_run_id'] = $test_prefix;
2359      $test_info['in_child_site'] = TRUE;
2360  
2361      foreach ($GLOBALS['databases']['default'] as &$value) {
2362        // Extract the current default database prefix.
2363        if (!isset($value['prefix'])) {
2364          $current_prefix = '';
2365        }
2366        elseif (is_array($value['prefix'])) {
2367          $current_prefix = $value['prefix']['default'];
2368        }
2369        else {
2370          $current_prefix = $value['prefix'];
2371        }
2372  
2373        // Remove the current database prefix and replace it by our own.
2374        $value['prefix'] = array(
2375          'default' => $current_prefix . $test_prefix,
2376        );
2377      }
2378    }
2379  
2380    // Initialize the database system. Note that the connection
2381    // won't be initialized until it is actually requested.
2382    require_once  DRUPAL_ROOT . '/includes/database/database.inc';
2383  
2384    // Register autoload functions so that we can access classes and interfaces.
2385    // The database autoload routine comes first so that we can load the database
2386    // system without hitting the database. That is especially important during
2387    // the install or upgrade process.
2388    spl_autoload_register('drupal_autoload_class');
2389    spl_autoload_register('drupal_autoload_interface');
2390  }
2391  
2392  /**
2393   * Loads system variables and all enabled bootstrap modules.
2394   */
2395  function _drupal_bootstrap_variables() {
2396    global $conf;
2397  
2398    // Initialize the lock system.
2399    require_once DRUPAL_ROOT . '/' . variable_get('lock_inc', 'includes/lock.inc');
2400    lock_initialize();
2401  
2402    // Load variables from the database, but do not overwrite variables set in settings.php.
2403    $conf = variable_initialize(isset($conf) ? $conf : array());
2404    // Load bootstrap modules.
2405    require_once  DRUPAL_ROOT . '/includes/module.inc';
2406    module_load_all(TRUE);
2407  }
2408  
2409  /**
2410   * Invokes hook_boot(), initializes locking system, and sends HTTP headers.
2411   */
2412  function _drupal_bootstrap_page_header() {
2413    bootstrap_invoke_all('boot');
2414  
2415    if (!drupal_is_cli()) {
2416      ob_start();
2417      drupal_page_header();
2418    }
2419  }
2420  
2421  /**
2422   * Returns the current bootstrap phase for this Drupal process.
2423   *
2424   * The current phase is the one most recently completed by drupal_bootstrap().
2425   *
2426   * @see drupal_bootstrap()
2427   */
2428  function drupal_get_bootstrap_phase() {
2429    return drupal_bootstrap();
2430  }
2431  
2432  /**
2433   * Returns the test prefix if this is an internal request from SimpleTest.
2434   *
2435   * @return
2436   *   Either the simpletest prefix (the string "simpletest" followed by any
2437   *   number of digits) or FALSE if the user agent does not contain a valid
2438   *   HMAC and timestamp.
2439   */
2440  function drupal_valid_test_ua() {
2441    global $drupal_hash_salt;
2442    // No reason to reset this.
2443    static $test_prefix;
2444  
2445    if (isset($test_prefix)) {
2446      return $test_prefix;
2447    }
2448  
2449    if (isset($_SERVER['HTTP_USER_AGENT']) && preg_match("/^(simpletest\d+);(.+);(.+);(.+)$/", $_SERVER['HTTP_USER_AGENT'], $matches)) {
2450      list(, $prefix, $time, $salt, $hmac) = $matches;
2451      $check_string =  $prefix . ';' . $time . ';' . $salt;
2452      // We use the salt from settings.php to make the HMAC key, since
2453      // the database is not yet initialized and we can't access any Drupal variables.
2454      // The file properties add more entropy not easily accessible to others.
2455      $key = $drupal_hash_salt . filectime(__FILE__) . fileinode(__FILE__);
2456      $time_diff = REQUEST_TIME - $time;
2457      // Since we are making a local request a 5 second time window is allowed,
2458      // and the HMAC must match.
2459      if ($time_diff >= 0 && $time_diff <= 5 && $hmac == drupal_hmac_base64($check_string, $key)) {
2460        $test_prefix = $prefix;
2461        return $test_prefix;
2462      }
2463    }
2464  
2465    $test_prefix = FALSE;
2466    return $test_prefix;
2467  }
2468  
2469  /**
2470   * Generates a user agent string with a HMAC and timestamp for simpletest.
2471   */
2472  function drupal_generate_test_ua($prefix) {
2473    global $drupal_hash_salt;
2474    static $key;
2475  
2476    if (!isset($key)) {
2477      // We use the salt from settings.php to make the HMAC key, since
2478      // the database is not yet initialized and we can't access any Drupal variables.
2479      // The file properties add more entropy not easily accessible to others.
2480      $key = $drupal_hash_salt . filectime(__FILE__) . fileinode(__FILE__);
2481    }
2482    // Generate a moderately secure HMAC based on the database credentials.
2483    $salt = uniqid('', TRUE);
2484    $check_string = $prefix . ';' . time() . ';' . $salt;
2485    return $check_string . ';' . drupal_hmac_base64($check_string, $key);
2486  }
2487  
2488  /**
2489   * Enables use of the theme system without requiring database access.
2490   *
2491   * Loads and initializes the theme system for site installs, updates and when
2492   * the site is in maintenance mode. This also applies when the database fails.
2493   *
2494   * @see _drupal_maintenance_theme()
2495   */
2496  function drupal_maintenance_theme() {
2497    require_once  DRUPAL_ROOT . '/includes/theme.maintenance.inc';
2498    _drupal_maintenance_theme();
2499  }
2500  
2501  /**
2502   * Returns a simple 404 Not Found page.
2503   *
2504   * If fast 404 pages are enabled, and this is a matching page then print a
2505   * simple 404 page and exit.
2506   *
2507   * This function is called from drupal_deliver_html_page() at the time when a
2508   * a normal 404 page is generated, but it can also optionally be called directly
2509   * from settings.php to prevent a Drupal bootstrap on these pages. See
2510   * documentation in settings.php for the benefits and drawbacks of using this.
2511   *
2512   * Paths to dynamically-generated content, such as image styles, should also be
2513   * accounted for in this function.
2514   */
2515  function drupal_fast_404() {
2516    $exclude_paths = variable_get('404_fast_paths_exclude', FALSE);
2517    if ($exclude_paths && !preg_match($exclude_paths, $_GET['q'])) {
2518      $fast_paths = variable_get('404_fast_paths', FALSE);
2519      if ($fast_paths && preg_match($fast_paths, $_GET['q'])) {
2520        drupal_add_http_header('Status', '404 Not Found');
2521        $fast_404_html = variable_get('404_fast_html', '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>404 Not Found</title></head><body><h1>Not Found</h1><p>The requested URL "@path" was not found on this server.</p></body></html>');
2522        // Replace @path in the variable with the page path.
2523        print strtr($fast_404_html, array('@path' => check_plain(request_uri())));
2524        exit;
2525      }
2526    }
2527  }
2528  
2529  /**
2530   * Returns TRUE if a Drupal installation is currently being attempted.
2531   */
2532  function drupal_installation_attempted() {
2533    return defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'install';
2534  }
2535  
2536  /**
2537   * Returns the name of the proper localization function.
2538   *
2539   * get_t() exists to support localization for code that might run during
2540   * the installation phase, when some elements of the system might not have
2541   * loaded.
2542   *
2543   * This would include implementations of hook_install(), which could run
2544   * during the Drupal installation phase, and might also be run during
2545   * non-installation time, such as while installing the module from the the
2546   * module administration page.
2547   *
2548   * Example usage:
2549   * @code
2550   *   $t = get_t();
2551   *   $translated = $t('translate this');
2552   * @endcode
2553   *
2554   * Use t() if your code will never run during the Drupal installation phase.
2555   * Use st() if your code will only run during installation and never any other
2556   * time. Use get_t() if your code could run in either circumstance.
2557   *
2558   * @see t()
2559   * @see st()
2560   * @ingroup sanitization
2561   */
2562  function get_t() {
2563    static $t;
2564    // This is not converted to drupal_static because there is no point in
2565    // resetting this as it can not change in the course of a request.
2566    if (!isset($t)) {
2567      $t = drupal_installation_attempted() ? 'st' : 't';
2568    }
2569    return $t;
2570  }
2571  
2572  /**
2573   * Initializes all the defined language types.
2574   */
2575  function drupal_language_initialize() {
2576    $types = language_types();
2577  
2578    // Ensure the language is correctly returned, even without multilanguage
2579    // support. Also make sure we have a $language fallback, in case a language
2580    // negotiation callback needs to do a full bootstrap.
2581    // Useful for eg. XML/HTML 'lang' attributes.
2582    $default = language_default();
2583    foreach ($types as $type) {
2584      $GLOBALS[$type] = $default;
2585    }
2586    if (drupal_multilingual()) {
2587      include_once  DRUPAL_ROOT . '/includes/language.inc';
2588      foreach ($types as $type) {
2589        $GLOBALS[$type] = language_initialize($type);
2590      }
2591      // Allow modules to react on language system initialization in multilingual
2592      // environments.
2593      bootstrap_invoke_all('language_init');
2594    }
2595  }
2596  
2597  /**
2598   * Returns a list of the built-in language types.
2599   *
2600   * @return
2601   *   An array of key-values pairs where the key is the language type and the
2602   *   value is its configurability.
2603   */
2604  function drupal_language_types() {
2605    return array(
2606      LANGUAGE_TYPE_INTERFACE => TRUE,
2607      LANGUAGE_TYPE_CONTENT => FALSE,
2608      LANGUAGE_TYPE_URL => FALSE,
2609    );
2610  }
2611  
2612  /**
2613   * Returns TRUE if there is more than one language enabled.
2614   *
2615   * @return
2616   *   TRUE if more than one language is enabled.
2617   */
2618  function drupal_multilingual() {
2619    // The "language_count" variable stores the number of enabled languages to
2620    // avoid unnecessarily querying the database when building the list of
2621    // enabled languages on monolingual sites.
2622    return variable_get('language_count', 1) > 1;
2623  }
2624  
2625  /**
2626   * Returns an array of the available language types.
2627   *
2628   * @return
2629   *   An array of all language types where the keys of each are the language type
2630   *   name and its value is its configurability (TRUE/FALSE).
2631   */
2632  function language_types() {
2633    return array_keys(variable_get('language_types', drupal_language_types()));
2634  }
2635  
2636  /**
2637   * Returns a list of installed languages, indexed by the specified key.
2638   *
2639   * @param $field
2640   *   (optional) The field to index the list with.
2641   *
2642   * @return
2643   *   An associative array, keyed on the values of $field.
2644   *   - If $field is 'weight' or 'enabled', the array is nested, with the outer
2645   *     array's values each being associative arrays with language codes as
2646   *     keys and language objects as values.
2647   *   - For all other values of $field, the array is only one level deep, and
2648   *     the array's values are language objects.
2649   */
2650  function language_list($field = 'language') {
2651    $languages = &drupal_static(__FUNCTION__);
2652    // Init language list
2653    if (!isset($languages)) {
2654      if (drupal_multilingual() || module_exists('locale')) {
2655        $languages['language'] = db_query('SELECT * FROM {languages} ORDER BY weight ASC, name ASC')->fetchAllAssoc('language');
2656        // Users cannot uninstall the native English language. However, we allow
2657        // it to be hidden from the installed languages. Therefore, at least one
2658        // other language must be enabled then.
2659        if (!$languages['language']['en']->enabled && !variable_get('language_native_enabled', TRUE)) {
2660          unset($languages['language']['en']);
2661        }
2662      }
2663      else {
2664        // No locale module, so use the default language only.
2665        $default = language_default();
2666        $languages['language'][$default->language] = $default;
2667      }
2668    }
2669  
2670    // Return the array indexed by the right field
2671    if (!isset($languages[$field])) {
2672      $languages[$field] = array();
2673      foreach ($languages['language'] as $lang) {
2674        // Some values should be collected into an array
2675        if (in_array($field, array('enabled', 'weight'))) {
2676          $languages[$field][$lang->$field][$lang->language] = $lang;
2677        }
2678        else {
2679          $languages[$field][$lang->$field] = $lang;
2680        }
2681      }
2682    }
2683    return $languages[$field];
2684  }
2685  
2686  /**
2687   * Returns the default language used on the site
2688   *
2689   * @param $property
2690   *   Optional property of the language object to return
2691   */
2692  function language_default($property = NULL) {
2693    $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' => ''));
2694    return $property ? $language->$property : $language;
2695  }
2696  
2697  /**
2698   * Returns the requested URL path of the page being viewed.
2699   *
2700   * Examples:
2701   * - http://example.com/node/306 returns "node/306".
2702   * - http://example.com/drupalfolder/node/306 returns "node/306" while
2703   *   base_path() returns "/drupalfolder/".
2704   * - http://example.com/path/alias (which is a path alias for node/306) returns
2705   *   "path/alias" as opposed to the internal path.
2706   * - http://example.com/index.php returns an empty string (meaning: front page).
2707   * - http://example.com/index.php?page=1 returns an empty string.
2708   *
2709   * @return
2710   *   The requested Drupal URL path.
2711   *
2712   * @see current_path()
2713   */
2714  function request_path() {
2715    static $path;
2716  
2717    if (isset($path)) {
2718      return $path;
2719    }
2720  
2721    if (isset($_GET['q']) && is_string($_GET['q'])) {
2722      // This is a request with a ?q=foo/bar query string. $_GET['q'] is
2723      // overwritten in drupal_path_initialize(), but request_path() is called
2724      // very early in the bootstrap process, so the original value is saved in
2725      // $path and returned in later calls.
2726      $path = $_GET['q'];
2727    }
2728    elseif (isset($_SERVER['REQUEST_URI'])) {
2729      // This request is either a clean URL, or 'index.php', or nonsense.
2730      // Extract the path from REQUEST_URI.
2731      $request_path = strtok($_SERVER['REQUEST_URI'], '?');
2732      $base_path_len = strlen(rtrim(dirname($_SERVER['SCRIPT_NAME']), '\/'));
2733      // Unescape and strip $base_path prefix, leaving q without a leading slash.
2734      $path = substr(urldecode($request_path), $base_path_len + 1);
2735      // If the path equals the script filename, either because 'index.php' was
2736      // explicitly provided in the URL, or because the server added it to
2737      // $_SERVER['REQUEST_URI'] even when it wasn't provided in the URL (some
2738      // versions of Microsoft IIS do this), the front page should be served.
2739      if ($path == basename($_SERVER['PHP_SELF'])) {
2740        $path = '';
2741      }
2742    }
2743    else {
2744      // This is the front page.
2745      $path = '';
2746    }
2747  
2748    // Under certain conditions Apache's RewriteRule directive prepends the value
2749    // assigned to $_GET['q'] with a slash. Moreover we can always have a trailing
2750    // slash in place, hence we need to normalize $_GET['q'].
2751    $path = trim($path, '/');
2752  
2753    return $path;
2754  }
2755  
2756  /**
2757   * Returns a component of the current Drupal path.
2758   *
2759   * When viewing a page at the path "admin/structure/types", for example, arg(0)
2760   * returns "admin", arg(1) returns "structure", and arg(2) returns "types".
2761   *
2762   * Avoid use of this function where possible, as resulting code is hard to
2763   * read. In menu callback functions, attempt to use named arguments. See the
2764   * explanation in menu.inc for how to construct callbacks that take arguments.
2765   * When attempting to use this function to load an element from the current
2766   * path, e.g. loading the node on a node page, use menu_get_object() instead.
2767   *
2768   * @param $index
2769   *   The index of the component, where each component is separated by a '/'
2770   *   (forward-slash), and where the first component has an index of 0 (zero).
2771   * @param $path
2772   *   A path to break into components. Defaults to the path of the current page.
2773   *
2774   * @return
2775   *   The component specified by $index, or NULL if the specified component was
2776   *   not found. If called without arguments, it returns an array containing all
2777   *   the components of the current path.
2778   */
2779  function arg($index = NULL, $path = NULL) {
2780    // Even though $arguments doesn't need to be resettable for any functional
2781    // reasons (the result of explode() does not depend on any run-time
2782    // information), it should be resettable anyway in case a module needs to
2783    // free up the memory used by it.
2784    // Use the advanced drupal_static() pattern, since this is called very often.
2785    static $drupal_static_fast;
2786    if (!isset($drupal_static_fast)) {
2787      $drupal_static_fast['arguments'] = &drupal_static(__FUNCTION__);
2788    }
2789    $arguments = &$drupal_static_fast['arguments'];
2790  
2791    if (!isset($path)) {
2792      $path = $_GET['q'];
2793    }
2794    if (!isset($arguments[$path])) {
2795      $arguments[$path] = explode('/', $path);
2796    }
2797    if (!isset($index)) {
2798      return $arguments[$path];
2799    }
2800    if (isset($arguments[$path][$index])) {
2801      return $arguments[$path][$index];
2802    }
2803  }
2804  
2805  /**
2806   * Returns the IP address of the client machine.
2807   *
2808   * If Drupal is behind a reverse proxy, we use the X-Forwarded-For header
2809   * instead of $_SERVER['REMOTE_ADDR'], which would be the IP address of
2810   * the proxy server, and not the client's. The actual header name can be
2811   * configured by the reverse_proxy_header variable.
2812   *
2813   * @return
2814   *   IP address of client machine, adjusted for reverse proxy and/or cluster
2815   *   environments.
2816   */
2817  function ip_address() {
2818    $ip_address = &drupal_static(__FUNCTION__);
2819  
2820    if (!isset($ip_address)) {
2821      $ip_address = $_SERVER['REMOTE_ADDR'];
2822  
2823      if (variable_get('reverse_proxy', 0)) {
2824        $reverse_proxy_header = variable_get('reverse_proxy_header', 'HTTP_X_FORWARDED_FOR');
2825        if (!empty($_SERVER[$reverse_proxy_header])) {
2826          // If an array of known reverse proxy IPs is provided, then trust
2827          // the XFF header if request really comes from one of them.
2828          $reverse_proxy_addresses = variable_get('reverse_proxy_addresses', array());
2829  
2830          // Turn XFF header into an array.
2831          $forwarded = explode(',', $_SERVER[$reverse_proxy_header]);
2832  
2833          // Trim the forwarded IPs; they may have been delimited by commas and spaces.
2834          $forwarded = array_map('trim', $forwarded);
2835  
2836          // Tack direct client IP onto end of forwarded array.
2837          $forwarded[] = $ip_address;
2838  
2839          // Eliminate all trusted IPs.
2840          $untrusted = array_diff($forwarded, $reverse_proxy_addresses);
2841  
2842          // The right-most IP is the most specific we can trust.
2843          $ip_address = array_pop($untrusted);
2844        }
2845      }
2846    }
2847  
2848    return $ip_address;
2849  }
2850  
2851  /**
2852   * @addtogroup schemaapi
2853   * @{
2854   */
2855  
2856  /**
2857   * Gets the schema definition of a table, or the whole database schema.
2858   *
2859   * The returned schema will include any modifications made by any
2860   * module that implements hook_schema_alter().
2861   *
2862   * @param $table
2863   *   The name of the table. If not given, the schema of all tables is returned.
2864   * @param $rebuild
2865   *   If true, the schema will be rebuilt instead of retrieved from the cache.
2866   */
2867  function drupal_get_schema($table = NULL, $rebuild = FALSE) {
2868    static $schema;
2869  
2870    if ($rebuild || !isset($table)) {
2871      $schema = drupal_get_complete_schema($rebuild);
2872    }
2873    elseif (!isset($schema)) {
2874      $schema = new SchemaCache();
2875    }
2876  
2877    if (!isset($table)) {
2878      return $schema;
2879    }
2880    if (isset($schema[$table])) {
2881      return $schema[$table];
2882    }
2883    else {
2884      return FALSE;
2885    }
2886  }
2887  
2888  /**
2889   * Extends DrupalCacheArray to allow for dynamic building of the schema cache.
2890   */
2891  class SchemaCache extends DrupalCacheArray {
2892  
2893    /**
2894     * Constructs a SchemaCache object.
2895     */
2896    public function __construct() {
2897      // Cache by request method.
2898      parent::__construct('schema:runtime:' . ($_SERVER['REQUEST_METHOD'] == 'GET'), 'cache');
2899    }
2900  
2901    /**
2902     * Overrides DrupalCacheArray::resolveCacheMiss().
2903     */
2904    protected function resolveCacheMiss($offset) {
2905      $complete_schema = drupal_get_complete_schema();
2906      $value = isset($complete_schema[$offset]) ? $complete_schema[$offset] :  NULL;
2907      $this->storage[$offset] = $value;
2908      $this->persist($offset);
2909      return $value;
2910    }
2911  }
2912  
2913  /**
2914   * Gets the whole database schema.
2915   *
2916   * The returned schema will include any modifications made by any
2917   * module that implements hook_schema_alter().
2918   *
2919   * @param $rebuild
2920   *   If true, the schema will be rebuilt instead of retrieved from the cache.
2921   */
2922  function drupal_get_complete_schema($rebuild = FALSE) {
2923    static $schema = array();
2924  
2925    if (empty($schema) || $rebuild) {
2926      // Try to load the schema from cache.
2927      if (!$rebuild && $cached = cache_get('schema')) {
2928        $schema = $cached->data;
2929      }
2930      // Otherwise, rebuild the schema cache.
2931      else {
2932        $schema = array();
2933        // Load the .install files to get hook_schema.
2934        // On some databases this function may be called before bootstrap has
2935        // been completed, so we force the functions we need to load just in case.
2936        if (function_exists('module_load_all_includes')) {
2937          // This function can be called very early in the bootstrap process, so
2938          // we force the module_list() cache to be refreshed to ensure that it
2939          // contains the complete list of modules before we go on to call
2940          // module_load_all_includes().
2941          module_list(TRUE);
2942          module_load_all_includes('install');
2943        }
2944  
2945        require_once  DRUPAL_ROOT . '/includes/common.inc';
2946        // Invoke hook_schema for all modules.
2947        foreach (module_implements('schema') as $module) {
2948          // Cast the result of hook_schema() to an array, as a NULL return value
2949          // would cause array_merge() to set the $schema variable to NULL as well.
2950          // That would break modules which use $schema further down the line.
2951          $current = (array) module_invoke($module, 'schema');
2952          // Set 'module' and 'name' keys for each table, and remove descriptions,
2953          // as they needlessly slow down cache_get() for every single request.
2954          _drupal_schema_initialize($current, $module);
2955          $schema = array_merge($schema, $current);
2956        }
2957  
2958        drupal_alter('schema', $schema);
2959        // If the schema is empty, avoid saving it: some database engines require
2960        // the schema to perform queries, and this could lead to infinite loops.
2961        if (!empty($schema) && (drupal_get_bootstrap_phase() == DRUPAL_BOOTSTRAP_FULL)) {
2962          cache_set('schema', $schema);
2963        }
2964        if ($rebuild) {
2965          cache_clear_all('schema:', 'cache', TRUE);
2966        }
2967      }
2968    }
2969  
2970    return $schema;
2971  }
2972  
2973  /**
2974   * @} End of "addtogroup schemaapi".
2975   */
2976  
2977  
2978  /**
2979   * @addtogroup registry
2980   * @{
2981   */
2982  
2983  /**
2984   * Confirms that an interface is available.
2985   *
2986   * This function is rarely called directly. Instead, it is registered as an
2987   * spl_autoload()  handler, and PHP calls it for us when necessary.
2988   *
2989   * @param $interface
2990   *   The name of the interface to check or load.
2991   *
2992   * @return
2993   *   TRUE if the interface is currently available, FALSE otherwise.
2994   */
2995  function drupal_autoload_interface($interface) {
2996    return _registry_check_code('interface', $interface);
2997  }
2998  
2999  /**
3000   * Confirms that a class is available.
3001   *
3002   * This function is rarely called directly. Instead, it is registered as an
3003   * spl_autoload()  handler, and PHP calls it for us when necessary.
3004   *
3005   * @param $class
3006   *   The name of the class to check or load.
3007   *
3008   * @return
3009   *   TRUE if the class is currently available, FALSE otherwise.
3010   */
3011  function drupal_autoload_class($class) {
3012    return _registry_check_code('class', $class);
3013  }
3014  
3015  /**
3016   * Checks for a resource in the registry.
3017   *
3018   * @param $type
3019   *   The type of resource we are looking up, or one of the constants
3020   *   REGISTRY_RESET_LOOKUP_CACHE or REGISTRY_WRITE_LOOKUP_CACHE, which
3021   *   signal that we should reset or write the cache, respectively.
3022   * @param $name
3023   *   The name of the resource, or NULL if either of the REGISTRY_* constants
3024   *   is passed in.
3025   *
3026   * @return
3027   *   TRUE if the resource was found, FALSE if not.
3028   *   NULL if either of the REGISTRY_* constants is passed in as $type.
3029   */
3030  function _registry_check_code($type, $name = NULL) {
3031    static $lookup_cache, $cache_update_needed;
3032  
3033    if ($type == 'class' && class_exists($name) || $type == 'interface' && interface_exists($name)) {
3034      return TRUE;
3035    }
3036  
3037    if (!isset($lookup_cache)) {
3038      $lookup_cache = array();
3039      if ($cache = cache_get('lookup_cache', 'cache_bootstrap')) {
3040        $lookup_cache = $cache->data;
3041      }
3042    }
3043  
3044    // When we rebuild the registry, we need to reset this cache so
3045    // we don't keep lookups for resources that changed during the rebuild.
3046    if ($type == REGISTRY_RESET_LOOKUP_CACHE) {
3047      $cache_update_needed = TRUE;
3048      $lookup_cache = NULL;
3049      return;
3050    }
3051  
3052    // Called from drupal_page_footer, we write to permanent storage if there
3053    // changes to the lookup cache for this request.
3054    if ($type == REGISTRY_WRITE_LOOKUP_CACHE) {
3055      if ($cache_update_needed) {
3056        cache_set('lookup_cache', $lookup_cache, 'cache_bootstrap');
3057      }
3058      return;
3059    }
3060  
3061    // $type is either 'interface' or 'class', so we only need the first letter to
3062    // keep the cache key unique.
3063    $cache_key = $type[0] . $name;
3064    if (isset($lookup_cache[$cache_key])) {
3065      if ($lookup_cache[$cache_key]) {
3066        require_once DRUPAL_ROOT . '/' . $lookup_cache[$cache_key];
3067      }
3068      return (bool) $lookup_cache[$cache_key];
3069    }
3070  
3071    // This function may get called when the default database is not active, but
3072    // there is no reason we'd ever want to not use the default database for
3073    // this query.
3074    $file = Database::getConnection('default', 'default')->query("SELECT filename FROM {registry} WHERE name = :name AND type = :type", array(
3075        ':name' => $name,
3076        ':type' => $type,
3077      ))
3078      ->fetchField();
3079  
3080    // Flag that we've run a lookup query and need to update the cache.
3081    $cache_update_needed = TRUE;
3082  
3083    // Misses are valuable information worth caching, so cache even if
3084    // $file is FALSE.
3085    $lookup_cache[$cache_key] = $file;
3086  
3087    if ($file) {
3088      require_once DRUPAL_ROOT . '/' . $file;
3089      return TRUE;
3090    }
3091    else {
3092      return FALSE;
3093    }
3094  }
3095  
3096  /**
3097   * Rescans all enabled modules and rebuilds the registry.
3098   *
3099   * Rescans all code in modules or includes directories, storing the location of
3100   * each interface or class in the database.
3101   */
3102  function registry_rebuild() {
3103    system_rebuild_module_data();
3104    registry_update();
3105  }
3106  
3107  /**
3108   * Updates the registry based on the latest files listed in the database.
3109   *
3110   * This function should be used when system_rebuild_module_data() does not need
3111   * to be called, because it is already known that the list of files in the
3112   * {system} table matches those in the file system.
3113   *
3114   * @return
3115   *   TRUE if the registry was rebuilt, FALSE if another thread was rebuilding
3116   *   in parallel and the current thread just waited for completion.
3117   *
3118   * @see registry_rebuild()
3119   */
3120  function registry_update() {
3121    // install_system_module() calls module_enable() which calls into this
3122    // function during initial system installation, so the lock system is neither
3123    // loaded nor does its storage exist yet.
3124    $in_installer = drupal_installation_attempted();
3125    if (!$in_installer && !lock_acquire(__FUNCTION__)) {
3126      // Another request got the lock, wait for it to finish.
3127      lock_wait(__FUNCTION__);
3128      return FALSE;
3129    }
3130  
3131    require_once  DRUPAL_ROOT . '/includes/registry.inc';
3132    _registry_update();
3133  
3134    if (!$in_installer) {
3135      lock_release(__FUNCTION__);
3136    }
3137    return TRUE;
3138  }
3139  
3140  /**
3141   * @} End of "addtogroup registry".
3142   */
3143  
3144  /**
3145   * Provides central static variable storage.
3146   *
3147   * All functions requiring a static variable to persist or cache data within
3148   * a single page request are encouraged to use this function unless it is
3149   * absolutely certain that the static variable will not need to be reset during
3150   * the page request. By centralizing static variable storage through this
3151   * function, other functions can rely on a consistent API for resetting any
3152   * other function's static variables.
3153   *
3154   * Example:
3155   * @code
3156   * function language_list($field = 'language') {
3157   *   $languages = &drupal_static(__FUNCTION__);
3158   *   if (!isset($languages)) {
3159   *     // If this function is being called for the first time after a reset,
3160   *     // query the database and execute any other code needed to retrieve
3161   *     // information about the supported languages.
3162   *     ...
3163   *   }
3164   *   if (!isset($languages[$field])) {
3165   *     // If this function is being called for the first time for a particular
3166   *     // index field, then execute code needed to index the information already
3167   *     // available in $languages by the desired field.
3168   *     ...
3169   *   }
3170   *   // Subsequent invocations of this function for a particular index field
3171   *   // skip the above two code blocks and quickly return the already indexed
3172   *   // information.
3173   *   return $languages[$field];
3174   * }
3175   * function locale_translate_overview_screen() {
3176   *   // When building the content for the translations overview page, make
3177   *   // sure to get completely fresh information about the supported languages.
3178   *   drupal_static_reset('language_list');
3179   *   ...
3180   * }
3181   * @endcode
3182   *
3183   * In a few cases, a function can have certainty that there is no legitimate
3184   * use-case for resetting that function's static variable. This is rare,
3185   * because when writing a function, it's hard to forecast all the situations in
3186   * which it will be used. A guideline is that if a function's static variable
3187   * does not depend on any information outside of the function that might change
3188   * during a single page request, then it's ok to use the "static" keyword
3189   * instead of the drupal_static() function.
3190   *
3191   * Example:
3192   * @code
3193   * function actions_do(...) {
3194   *   // $stack tracks the number of recursive calls.
3195   *   static $stack;
3196   *   $stack++;
3197   *   if ($stack > variable_get('actions_max_stack', 35)) {
3198   *     ...
3199   *     return;
3200   *   }
3201   *   ...
3202   *   $stack--;
3203   * }
3204   * @endcode
3205   *
3206   * In a few cases, a function needs a resettable static variable, but the
3207   * function is called many times (100+) during a single page request, so
3208   * every microsecond of execution time that can be removed from the function
3209   * counts. These functions can use a more cumbersome, but faster variant of
3210   * calling drupal_static(). It works by storing the reference returned by
3211   * drupal_static() in the calling function's own static variable, thereby
3212   * removing the need to call drupal_static() for each iteration of the function.
3213   * Conceptually, it replaces:
3214   * @code
3215   * $foo = &drupal_static(__FUNCTION__);
3216   * @endcode
3217   * with:
3218   * @code
3219   * // Unfortunately, this does not work.
3220   * static $foo = &drupal_static(__FUNCTION__);
3221   * @endcode
3222   * However, the above line of code does not work, because PHP only allows static
3223   * variables to be initializied by literal values, and does not allow static
3224   * variables to be assigned to references.
3225   * - http://php.net/manual/en/language.variables.scope.php#language.variables.scope.static
3226   * - http://php.net/manual/en/language.variables.scope.php#language.variables.scope.references
3227   * The example below shows the syntax needed to work around both limitations.
3228   * For benchmarks and more information, see http://drupal.org/node/619666.
3229   *
3230   * Example:
3231   * @code
3232   * function user_access($string, $account = NULL) {
3233   *   // Use the advanced drupal_static() pattern, since this is called very often.
3234   *   static $drupal_static_fast;
3235   *   if (!isset($drupal_static_fast)) {
3236   *     $drupal_static_fast['perm'] = &drupal_static(__FUNCTION__);
3237   *   }
3238   *   $perm = &$drupal_static_fast['perm'];
3239   *   ...
3240   * }
3241   * @endcode
3242   *
3243   * @param $name
3244   *   Globally unique name for the variable. For a function with only one static,
3245   *   variable, the function name (e.g. via the PHP magic __FUNCTION__ constant)
3246   *   is recommended. For a function with multiple static variables add a
3247   *   distinguishing suffix to the function name for each one.
3248   * @param $default_value
3249   *   Optional default value.
3250   * @param $reset
3251   *   TRUE to reset a specific named variable, or all variables if $name is NULL.
3252   *   Resetting every variable should only be used, for example, for running
3253   *   unit tests with a clean environment. Should be used only though via
3254   *   function drupal_static_reset() and the return value should not be used in
3255   *   this case.
3256   *
3257   * @return
3258   *   Returns a variable by reference.
3259   *
3260   * @see drupal_static_reset()
3261   */
3262  function &drupal_static($name, $default_value = NULL, $reset = FALSE) {
3263    static $data = array(), $default = array();
3264    // First check if dealing with a previously defined static variable.
3265    if (isset($data[$name]) || array_key_exists($name, $data)) {
3266      // Non-NULL $name and both $data[$name] and $default[$name] statics exist.
3267      if ($reset) {
3268        // Reset pre-existing static variable to its default value.
3269        $data[$name] = $default[$name];
3270      }
3271      return $data[$name];
3272    }
3273    // Neither $data[$name] nor $default[$name] static variables exist.
3274    if (isset($name)) {
3275      if ($reset) {
3276        // Reset was called before a default is set and yet a variable must be
3277        // returned.
3278        return $data;
3279      }
3280      // First call with new non-NULL $name. Initialize a new static variable.
3281      $default[$name] = $data[$name] = $default_value;
3282      return $data[$name];
3283    }
3284    // Reset all: ($name == NULL). This needs to be done one at a time so that
3285    // references returned by earlier invocations of drupal_static() also get
3286    // reset.
3287    foreach ($default as $name => $value) {
3288      $data[$name] = $value;
3289    }
3290    // As the function returns a reference, the return should always be a
3291    // variable.
3292    return $data;
3293  }
3294  
3295  /**
3296   * Resets one or all centrally stored static variable(s).
3297   *
3298   * @param $name
3299   *   Name of the static variable to reset. Omit to reset all variables.
3300   */
3301  function drupal_static_reset($name = NULL) {
3302    drupal_static($name, NULL, TRUE);
3303  }
3304  
3305  /**
3306   * Detects whether the current script is running in a command-line environment.
3307   */
3308  function drupal_is_cli() {
3309    return (!isset($_SERVER['SERVER_SOFTWARE']) && (php_sapi_name() == 'cli' || (is_numeric($_SERVER['argc']) && $_SERVER['argc'] > 0)));
3310  }
3311  
3312  /**
3313   * Formats text for emphasized display in a placeholder inside a sentence.
3314   *
3315   * Used automatically by format_string().
3316   *
3317   * @param $text
3318   *   The text to format (plain-text).
3319   *
3320   * @return
3321   *   The formatted text (html).
3322   */
3323  function drupal_placeholder($text) {
3324    return '<em class="placeholder">' . check_plain($text) . '</em>';
3325  }
3326  
3327  /**
3328   * Registers a function for execution on shutdown.
3329   *
3330   * Wrapper for register_shutdown_function() that catches thrown exceptions to
3331   * avoid "Exception thrown without a stack frame in Unknown".
3332   *
3333   * @param $callback
3334   *   The shutdown function to register.
3335   * @param ...
3336   *   Additional arguments to pass to the shutdown function.
3337   *
3338   * @return
3339   *   Array of shutdown functions to be executed.
3340   *
3341   * @see register_shutdown_function()
3342   * @ingroup php_wrappers
3343   */
3344  function &drupal_register_shutdown_function($callback = NULL) {
3345    // We cannot use drupal_static() here because the static cache is reset during
3346    // batch processing, which breaks batch handling.
3347    static $callbacks = array();
3348  
3349    if (isset($callback)) {
3350      // Only register the internal shutdown function once.
3351      if (empty($callbacks)) {
3352        register_shutdown_function('_drupal_shutdown_function');
3353      }
3354      $args = func_get_args();
3355      array_shift($args);
3356      // Save callback and arguments
3357      $callbacks[] = array('callback' => $callback, 'arguments' => $args);
3358    }
3359    return $callbacks;
3360  }
3361  
3362  /**
3363   * Executes registered shutdown functions.
3364   */
3365  function _drupal_shutdown_function() {
3366    $callbacks = &drupal_register_shutdown_function();
3367  
3368    // Set the CWD to DRUPAL_ROOT as it is not guaranteed to be the same as it
3369    // was in the normal context of execution.
3370    chdir(DRUPAL_ROOT);
3371  
3372    try {
3373      while (list($key, $callback) = each($callbacks)) {
3374        call_user_func_array($callback['callback'], $callback['arguments']);
3375      }
3376    }
3377    catch (Exception $exception) {
3378      // If we are displaying errors, then do so with no possibility of a further uncaught exception being thrown.
3379     require_once  DRUPAL_ROOT . '/includes/errors.inc';
3380     if (error_displayable()) {
3381        print '<h1>Uncaught exception thrown in shutdown function.</h1>';
3382        print '<p>' . _drupal_render_exception_safe($exception) . '</p><hr />';
3383      }
3384    }
3385  }