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Differences Between: [Versions 310 and 403] [Versions 311 and 403] [Versions 39 and 403] [Versions 400 and 403] [Versions 401 and 403] [Versions 402 and 403]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Library of functions for web output
  19   *
  20   * Library of all general-purpose Moodle PHP functions and constants
  21   * that produce HTML output
  22   *
  23   * Other main libraries:
  24   * - datalib.php - functions that access the database.
  25   * - moodlelib.php - general-purpose Moodle functions.
  26   *
  27   * @package    core
  28   * @subpackage lib
  29   * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}
  30   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  31   */
  32  
  33  defined('MOODLE_INTERNAL') || die();
  34  
  35  // Constants.
  36  
  37  // Define text formatting types ... eventually we can add Wiki, BBcode etc.
  38  
  39  /**
  40   * Does all sorts of transformations and filtering.
  41   */
  42  define('FORMAT_MOODLE',   '0');
  43  
  44  /**
  45   * Plain HTML (with some tags stripped).
  46   */
  47  define('FORMAT_HTML',     '1');
  48  
  49  /**
  50   * Plain text (even tags are printed in full).
  51   */
  52  define('FORMAT_PLAIN',    '2');
  53  
  54  /**
  55   * Wiki-formatted text.
  56   * Deprecated: left here just to note that '3' is not used (at the moment)
  57   * and to catch any latent wiki-like text (which generates an error)
  58   * @deprecated since 2005!
  59   */
  60  define('FORMAT_WIKI',     '3');
  61  
  62  /**
  63   * Markdown-formatted text http://daringfireball.net/projects/markdown/
  64   */
  65  define('FORMAT_MARKDOWN', '4');
  66  
  67  /**
  68   * A moodle_url comparison using this flag will return true if the base URLs match, params are ignored.
  69   */
  70  define('URL_MATCH_BASE', 0);
  71  
  72  /**
  73   * A moodle_url comparison using this flag will return true if the base URLs match and the params of url1 are part of url2.
  74   */
  75  define('URL_MATCH_PARAMS', 1);
  76  
  77  /**
  78   * A moodle_url comparison using this flag will return true if the two URLs are identical, except for the order of the params.
  79   */
  80  define('URL_MATCH_EXACT', 2);
  81  
  82  // Functions.
  83  
  84  /**
  85   * Add quotes to HTML characters.
  86   *
  87   * Returns $var with HTML characters (like "<", ">", etc.) properly quoted.
  88   * Related function {@link p()} simply prints the output of this function.
  89   *
  90   * @param string $var the string potentially containing HTML characters
  91   * @return string
  92   */
  93  function s($var) {
  94      if ($var === false) {
  95          return '0';
  96      }
  97  
  98      if ($var === null || $var === '') {
  99          return '';
 100      }
 101  
 102      return preg_replace(
 103          '/&amp;#(\d+|x[0-9a-f]+);/i', '&#$1;',
 104          htmlspecialchars($var, ENT_QUOTES | ENT_HTML401 | ENT_SUBSTITUTE)
 105      );
 106  }
 107  
 108  /**
 109   * Add quotes to HTML characters.
 110   *
 111   * Prints $var with HTML characters (like "<", ">", etc.) properly quoted.
 112   * This function simply calls & displays {@link s()}.
 113   * @see s()
 114   *
 115   * @param string $var the string potentially containing HTML characters
 116   */
 117  function p($var) {
 118      echo s($var);
 119  }
 120  
 121  /**
 122   * Does proper javascript quoting.
 123   *
 124   * Do not use addslashes anymore, because it does not work when magic_quotes_sybase is enabled.
 125   *
 126   * @param mixed $var String, Array, or Object to add slashes to
 127   * @return mixed quoted result
 128   */
 129  function addslashes_js($var) {
 130      if (is_string($var)) {
 131          $var = str_replace('\\', '\\\\', $var);
 132          $var = str_replace(array('\'', '"', "\n", "\r", "\0"), array('\\\'', '\\"', '\\n', '\\r', '\\0'), $var);
 133          $var = str_replace('</', '<\/', $var);   // XHTML compliance.
 134      } else if (is_array($var)) {
 135          $var = array_map('addslashes_js', $var);
 136      } else if (is_object($var)) {
 137          $a = get_object_vars($var);
 138          foreach ($a as $key => $value) {
 139              $a[$key] = addslashes_js($value);
 140          }
 141          $var = (object)$a;
 142      }
 143      return $var;
 144  }
 145  
 146  /**
 147   * Remove query string from url.
 148   *
 149   * Takes in a URL and returns it without the querystring portion.
 150   *
 151   * @param string $url the url which may have a query string attached.
 152   * @return string The remaining URL.
 153   */
 154  function strip_querystring($url) {
 155      if ($url === null || $url === '') {
 156          return '';
 157      }
 158  
 159      if ($commapos = strpos($url, '?')) {
 160          return substr($url, 0, $commapos);
 161      } else {
 162          return $url;
 163      }
 164  }
 165  
 166  /**
 167   * Returns the name of the current script, WITH the querystring portion.
 168   *
 169   * This function is necessary because PHP_SELF and REQUEST_URI and SCRIPT_NAME
 170   * return different things depending on a lot of things like your OS, Web
 171   * server, and the way PHP is compiled (ie. as a CGI, module, ISAPI, etc.)
 172   * <b>NOTE:</b> This function returns false if the global variables needed are not set.
 173   *
 174   * @return mixed String or false if the global variables needed are not set.
 175   */
 176  function me() {
 177      global $ME;
 178      return $ME;
 179  }
 180  
 181  /**
 182   * Guesses the full URL of the current script.
 183   *
 184   * This function is using $PAGE->url, but may fall back to $FULLME which
 185   * is constructed from  PHP_SELF and REQUEST_URI or SCRIPT_NAME
 186   *
 187   * @return mixed full page URL string or false if unknown
 188   */
 189  function qualified_me() {
 190      global $FULLME, $PAGE, $CFG;
 191  
 192      if (isset($PAGE) and $PAGE->has_set_url()) {
 193          // This is the only recommended way to find out current page.
 194          return $PAGE->url->out(false);
 195  
 196      } else {
 197          if ($FULLME === null) {
 198              // CLI script most probably.
 199              return false;
 200          }
 201          if (!empty($CFG->sslproxy)) {
 202              // Return only https links when using SSL proxy.
 203              return preg_replace('/^http:/', 'https:', $FULLME, 1);
 204          } else {
 205              return $FULLME;
 206          }
 207      }
 208  }
 209  
 210  /**
 211   * Determines whether or not the Moodle site is being served over HTTPS.
 212   *
 213   * This is done simply by checking the value of $CFG->wwwroot, which seems
 214   * to be the only reliable method.
 215   *
 216   * @return boolean True if site is served over HTTPS, false otherwise.
 217   */
 218  function is_https() {
 219      global $CFG;
 220  
 221      return (strpos($CFG->wwwroot, 'https://') === 0);
 222  }
 223  
 224  /**
 225   * Returns the cleaned local URL of the HTTP_REFERER less the URL query string parameters if required.
 226   *
 227   * @param bool $stripquery if true, also removes the query part of the url.
 228   * @return string The resulting referer or empty string.
 229   */
 230  function get_local_referer($stripquery = true) {
 231      if (isset($_SERVER['HTTP_REFERER'])) {
 232          $referer = clean_param($_SERVER['HTTP_REFERER'], PARAM_LOCALURL);
 233          if ($stripquery) {
 234              return strip_querystring($referer);
 235          } else {
 236              return $referer;
 237          }
 238      } else {
 239          return '';
 240      }
 241  }
 242  
 243  /**
 244   * Class for creating and manipulating urls.
 245   *
 246   * It can be used in moodle pages where config.php has been included without any further includes.
 247   *
 248   * It is useful for manipulating urls with long lists of params.
 249   * One situation where it will be useful is a page which links to itself to perform various actions
 250   * and / or to process form data. A moodle_url object :
 251   * can be created for a page to refer to itself with all the proper get params being passed from page call to
 252   * page call and methods can be used to output a url including all the params, optionally adding and overriding
 253   * params and can also be used to
 254   *     - output the url without any get params
 255   *     - and output the params as hidden fields to be output within a form
 256   *
 257   * @copyright 2007 jamiesensei
 258   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 259   * @package core
 260   */
 261  class moodle_url {
 262  
 263      /**
 264       * Scheme, ex.: http, https
 265       * @var string
 266       */
 267      protected $scheme = '';
 268  
 269      /**
 270       * Hostname.
 271       * @var string
 272       */
 273      protected $host = '';
 274  
 275      /**
 276       * Port number, empty means default 80 or 443 in case of http.
 277       * @var int
 278       */
 279      protected $port = '';
 280  
 281      /**
 282       * Username for http auth.
 283       * @var string
 284       */
 285      protected $user = '';
 286  
 287      /**
 288       * Password for http auth.
 289       * @var string
 290       */
 291      protected $pass = '';
 292  
 293      /**
 294       * Script path.
 295       * @var string
 296       */
 297      protected $path = '';
 298  
 299      /**
 300       * Optional slash argument value.
 301       * @var string
 302       */
 303      protected $slashargument = '';
 304  
 305      /**
 306       * Anchor, may be also empty, null means none.
 307       * @var string
 308       */
 309      protected $anchor = null;
 310  
 311      /**
 312       * Url parameters as associative array.
 313       * @var array
 314       */
 315      protected $params = array();
 316  
 317      /**
 318       * Create new instance of moodle_url.
 319       *
 320       * @param moodle_url|string $url - moodle_url means make a copy of another
 321       *      moodle_url and change parameters, string means full url or shortened
 322       *      form (ex.: '/course/view.php'). It is strongly encouraged to not include
 323       *      query string because it may result in double encoded values. Use the
 324       *      $params instead. For admin URLs, just use /admin/script.php, this
 325       *      class takes care of the $CFG->admin issue.
 326       * @param array $params these params override current params or add new
 327       * @param string $anchor The anchor to use as part of the URL if there is one.
 328       * @throws moodle_exception
 329       */
 330      public function __construct($url, array $params = null, $anchor = null) {
 331          global $CFG;
 332  
 333          if ($url instanceof moodle_url) {
 334              $this->scheme = $url->scheme;
 335              $this->host = $url->host;
 336              $this->port = $url->port;
 337              $this->user = $url->user;
 338              $this->pass = $url->pass;
 339              $this->path = $url->path;
 340              $this->slashargument = $url->slashargument;
 341              $this->params = $url->params;
 342              $this->anchor = $url->anchor;
 343  
 344          } else {
 345              $url = $url ?? '';
 346              // Detect if anchor used.
 347              $apos = strpos($url, '#');
 348              if ($apos !== false) {
 349                  $anchor = substr($url, $apos);
 350                  $anchor = ltrim($anchor, '#');
 351                  $this->set_anchor($anchor);
 352                  $url = substr($url, 0, $apos);
 353              }
 354  
 355              // Normalise shortened form of our url ex.: '/course/view.php'.
 356              if (strpos($url, '/') === 0) {
 357                  $url = $CFG->wwwroot.$url;
 358              }
 359  
 360              if ($CFG->admin !== 'admin') {
 361                  if (strpos($url, "$CFG->wwwroot/admin/") === 0) {
 362                      $url = str_replace("$CFG->wwwroot/admin/", "$CFG->wwwroot/$CFG->admin/", $url);
 363                  }
 364              }
 365  
 366              // Parse the $url.
 367              $parts = parse_url($url);
 368              if ($parts === false) {
 369                  throw new moodle_exception('invalidurl');
 370              }
 371              if (isset($parts['query'])) {
 372                  // Note: the values may not be correctly decoded, url parameters should be always passed as array.
 373                  parse_str(str_replace('&amp;', '&', $parts['query']), $this->params);
 374              }
 375              unset($parts['query']);
 376              foreach ($parts as $key => $value) {
 377                  $this->$key = $value;
 378              }
 379  
 380              // Detect slashargument value from path - we do not support directory names ending with .php.
 381              $pos = strpos($this->path, '.php/');
 382              if ($pos !== false) {
 383                  $this->slashargument = substr($this->path, $pos + 4);
 384                  $this->path = substr($this->path, 0, $pos + 4);
 385              }
 386          }
 387  
 388          $this->params($params);
 389          if ($anchor !== null) {
 390              $this->anchor = (string)$anchor;
 391          }
 392      }
 393  
 394      /**
 395       * Add an array of params to the params for this url.
 396       *
 397       * The added params override existing ones if they have the same name.
 398       *
 399       * @param array $params Defaults to null. If null then returns all params.
 400       * @return array Array of Params for url.
 401       * @throws coding_exception
 402       */
 403      public function params(array $params = null) {
 404          $params = (array)$params;
 405  
 406          foreach ($params as $key => $value) {
 407              if (is_int($key)) {
 408                  throw new coding_exception('Url parameters can not have numeric keys!');
 409              }
 410              if (!is_string($value)) {
 411                  if (is_array($value)) {
 412                      throw new coding_exception('Url parameters values can not be arrays!');
 413                  }
 414                  if (is_object($value) and !method_exists($value, '__toString')) {
 415                      throw new coding_exception('Url parameters values can not be objects, unless __toString() is defined!');
 416                  }
 417              }
 418              $this->params[$key] = (string)$value;
 419          }
 420          return $this->params;
 421      }
 422  
 423      /**
 424       * Remove all params if no arguments passed.
 425       * Remove selected params if arguments are passed.
 426       *
 427       * Can be called as either remove_params('param1', 'param2')
 428       * or remove_params(array('param1', 'param2')).
 429       *
 430       * @param string[]|string $params,... either an array of param names, or 1..n string params to remove as args.
 431       * @return array url parameters
 432       */
 433      public function remove_params($params = null) {
 434          if (!is_array($params)) {
 435              $params = func_get_args();
 436          }
 437          foreach ($params as $param) {
 438              unset($this->params[$param]);
 439          }
 440          return $this->params;
 441      }
 442  
 443      /**
 444       * Remove all url parameters.
 445       *
 446       * @todo remove the unused param.
 447       * @param array $params Unused param
 448       * @return void
 449       */
 450      public function remove_all_params($params = null) {
 451          $this->params = array();
 452          $this->slashargument = '';
 453      }
 454  
 455      /**
 456       * Add a param to the params for this url.
 457       *
 458       * The added param overrides existing one if they have the same name.
 459       *
 460       * @param string $paramname name
 461       * @param string $newvalue Param value. If new value specified current value is overriden or parameter is added
 462       * @return mixed string parameter value, null if parameter does not exist
 463       */
 464      public function param($paramname, $newvalue = '') {
 465          if (func_num_args() > 1) {
 466              // Set new value.
 467              $this->params(array($paramname => $newvalue));
 468          }
 469          if (isset($this->params[$paramname])) {
 470              return $this->params[$paramname];
 471          } else {
 472              return null;
 473          }
 474      }
 475  
 476      /**
 477       * Merges parameters and validates them
 478       *
 479       * @param array $overrideparams
 480       * @return array merged parameters
 481       * @throws coding_exception
 482       */
 483      protected function merge_overrideparams(array $overrideparams = null) {
 484          $overrideparams = (array)$overrideparams;
 485          $params = $this->params;
 486          foreach ($overrideparams as $key => $value) {
 487              if (is_int($key)) {
 488                  throw new coding_exception('Overridden parameters can not have numeric keys!');
 489              }
 490              if (is_array($value)) {
 491                  throw new coding_exception('Overridden parameters values can not be arrays!');
 492              }
 493              if (is_object($value) and !method_exists($value, '__toString')) {
 494                  throw new coding_exception('Overridden parameters values can not be objects, unless __toString() is defined!');
 495              }
 496              $params[$key] = (string)$value;
 497          }
 498          return $params;
 499      }
 500  
 501      /**
 502       * Get the params as as a query string.
 503       *
 504       * This method should not be used outside of this method.
 505       *
 506       * @param bool $escaped Use &amp; as params separator instead of plain &
 507       * @param array $overrideparams params to add to the output params, these
 508       *      override existing ones with the same name.
 509       * @return string query string that can be added to a url.
 510       */
 511      public function get_query_string($escaped = true, array $overrideparams = null) {
 512          $arr = array();
 513          if ($overrideparams !== null) {
 514              $params = $this->merge_overrideparams($overrideparams);
 515          } else {
 516              $params = $this->params;
 517          }
 518          foreach ($params as $key => $val) {
 519              if (is_array($val)) {
 520                  foreach ($val as $index => $value) {
 521                      $arr[] = rawurlencode($key.'['.$index.']')."=".rawurlencode($value);
 522                  }
 523              } else {
 524                  if (isset($val) && $val !== '') {
 525                      $arr[] = rawurlencode($key)."=".rawurlencode($val);
 526                  } else {
 527                      $arr[] = rawurlencode($key);
 528                  }
 529              }
 530          }
 531          if ($escaped) {
 532              return implode('&amp;', $arr);
 533          } else {
 534              return implode('&', $arr);
 535          }
 536      }
 537  
 538      /**
 539       * Get the url params as an array of key => value pairs.
 540       *
 541       * This helps in handling cases where url params contain arrays.
 542       *
 543       * @return array params array for templates.
 544       */
 545      public function export_params_for_template(): array {
 546          $data = [];
 547          foreach ($this->params as $key => $val) {
 548              if (is_array($val)) {
 549                  foreach ($val as $index => $value) {
 550                      $data[] = ['name' => $key.'['.$index.']', 'value' => $value];
 551                  }
 552              } else {
 553                  $data[] = ['name' => $key, 'value' => $val];
 554              }
 555          }
 556          return $data;
 557      }
 558  
 559      /**
 560       * Shortcut for printing of encoded URL.
 561       *
 562       * @return string
 563       */
 564      public function __toString() {
 565          return $this->out(true);
 566      }
 567  
 568      /**
 569       * Output url.
 570       *
 571       * If you use the returned URL in HTML code, you want the escaped ampersands. If you use
 572       * the returned URL in HTTP headers, you want $escaped=false.
 573       *
 574       * @param bool $escaped Use &amp; as params separator instead of plain &
 575       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 576       * @return string Resulting URL
 577       */
 578      public function out($escaped = true, array $overrideparams = null) {
 579  
 580          global $CFG;
 581  
 582          if (!is_bool($escaped)) {
 583              debugging('Escape parameter must be of type boolean, '.gettype($escaped).' given instead.');
 584          }
 585  
 586          $url = $this;
 587  
 588          // Allow url's to be rewritten by a plugin.
 589          if (isset($CFG->urlrewriteclass) && !isset($CFG->upgraderunning)) {
 590              $class = $CFG->urlrewriteclass;
 591              $pluginurl = $class::url_rewrite($url);
 592              if ($pluginurl instanceof moodle_url) {
 593                  $url = $pluginurl;
 594              }
 595          }
 596  
 597          return $url->raw_out($escaped, $overrideparams);
 598  
 599      }
 600  
 601      /**
 602       * Output url without any rewrites
 603       *
 604       * This is identical in signature and use to out() but doesn't call the rewrite handler.
 605       *
 606       * @param bool $escaped Use &amp; as params separator instead of plain &
 607       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 608       * @return string Resulting URL
 609       */
 610      public function raw_out($escaped = true, array $overrideparams = null) {
 611          if (!is_bool($escaped)) {
 612              debugging('Escape parameter must be of type boolean, '.gettype($escaped).' given instead.');
 613          }
 614  
 615          $uri = $this->out_omit_querystring().$this->slashargument;
 616  
 617          $querystring = $this->get_query_string($escaped, $overrideparams);
 618          if ($querystring !== '') {
 619              $uri .= '?' . $querystring;
 620          }
 621          if (!is_null($this->anchor)) {
 622              $uri .= '#'.$this->anchor;
 623          }
 624  
 625          return $uri;
 626      }
 627  
 628      /**
 629       * Returns url without parameters, everything before '?'.
 630       *
 631       * @param bool $includeanchor if {@link self::anchor} is defined, should it be returned?
 632       * @return string
 633       */
 634      public function out_omit_querystring($includeanchor = false) {
 635  
 636          $uri = $this->scheme ? $this->scheme.':'.((strtolower($this->scheme) == 'mailto') ? '':'//'): '';
 637          $uri .= $this->user ? $this->user.($this->pass? ':'.$this->pass:'').'@':'';
 638          $uri .= $this->host ? $this->host : '';
 639          $uri .= $this->port ? ':'.$this->port : '';
 640          $uri .= $this->path ? $this->path : '';
 641          if ($includeanchor and !is_null($this->anchor)) {
 642              $uri .= '#' . $this->anchor;
 643          }
 644  
 645          return $uri;
 646      }
 647  
 648      /**
 649       * Compares this moodle_url with another.
 650       *
 651       * See documentation of constants for an explanation of the comparison flags.
 652       *
 653       * @param moodle_url $url The moodle_url object to compare
 654       * @param int $matchtype The type of comparison (URL_MATCH_BASE, URL_MATCH_PARAMS, URL_MATCH_EXACT)
 655       * @return bool
 656       */
 657      public function compare(moodle_url $url, $matchtype = URL_MATCH_EXACT) {
 658  
 659          $baseself = $this->out_omit_querystring();
 660          $baseother = $url->out_omit_querystring();
 661  
 662          // Append index.php if there is no specific file.
 663          if (substr($baseself, -1) == '/') {
 664              $baseself .= 'index.php';
 665          }
 666          if (substr($baseother, -1) == '/') {
 667              $baseother .= 'index.php';
 668          }
 669  
 670          // Compare the two base URLs.
 671          if ($baseself != $baseother) {
 672              return false;
 673          }
 674  
 675          if ($matchtype == URL_MATCH_BASE) {
 676              return true;
 677          }
 678  
 679          $urlparams = $url->params();
 680          foreach ($this->params() as $param => $value) {
 681              if ($param == 'sesskey') {
 682                  continue;
 683              }
 684              if (!array_key_exists($param, $urlparams) || $urlparams[$param] != $value) {
 685                  return false;
 686              }
 687          }
 688  
 689          if ($matchtype == URL_MATCH_PARAMS) {
 690              return true;
 691          }
 692  
 693          foreach ($urlparams as $param => $value) {
 694              if ($param == 'sesskey') {
 695                  continue;
 696              }
 697              if (!array_key_exists($param, $this->params()) || $this->param($param) != $value) {
 698                  return false;
 699              }
 700          }
 701  
 702          if ($url->anchor !== $this->anchor) {
 703              return false;
 704          }
 705  
 706          return true;
 707      }
 708  
 709      /**
 710       * Sets the anchor for the URI (the bit after the hash)
 711       *
 712       * @param string $anchor null means remove previous
 713       */
 714      public function set_anchor($anchor) {
 715          if (is_null($anchor)) {
 716              // Remove.
 717              $this->anchor = null;
 718          } else if ($anchor === '') {
 719              // Special case, used as empty link.
 720              $this->anchor = '';
 721          } else if (preg_match('|[a-zA-Z\_\:][a-zA-Z0-9\_\-\.\:]*|', $anchor)) {
 722              // Match the anchor against the NMTOKEN spec.
 723              $this->anchor = $anchor;
 724          } else {
 725              // Bad luck, no valid anchor found.
 726              $this->anchor = null;
 727          }
 728      }
 729  
 730      /**
 731       * Sets the scheme for the URI (the bit before ://)
 732       *
 733       * @param string $scheme
 734       */
 735      public function set_scheme($scheme) {
 736          // See http://www.ietf.org/rfc/rfc3986.txt part 3.1.
 737          if (preg_match('/^[a-zA-Z][a-zA-Z0-9+.-]*$/', $scheme)) {
 738              $this->scheme = $scheme;
 739          } else {
 740              throw new coding_exception('Bad URL scheme.');
 741          }
 742      }
 743  
 744      /**
 745       * Sets the url slashargument value.
 746       *
 747       * @param string $path usually file path
 748       * @param string $parameter name of page parameter if slasharguments not supported
 749       * @param bool $supported usually null, then it depends on $CFG->slasharguments, use true or false for other servers
 750       * @return void
 751       */
 752      public function set_slashargument($path, $parameter = 'file', $supported = null) {
 753          global $CFG;
 754          if (is_null($supported)) {
 755              $supported = !empty($CFG->slasharguments);
 756          }
 757  
 758          if ($supported) {
 759              $parts = explode('/', $path);
 760              $parts = array_map('rawurlencode', $parts);
 761              $path  = implode('/', $parts);
 762              $this->slashargument = $path;
 763              unset($this->params[$parameter]);
 764  
 765          } else {
 766              $this->slashargument = '';
 767              $this->params[$parameter] = $path;
 768          }
 769      }
 770  
 771      // Static factory methods.
 772  
 773      /**
 774       * General moodle file url.
 775       *
 776       * @param string $urlbase the script serving the file
 777       * @param string $path
 778       * @param bool $forcedownload
 779       * @return moodle_url
 780       */
 781      public static function make_file_url($urlbase, $path, $forcedownload = false) {
 782          $params = array();
 783          if ($forcedownload) {
 784              $params['forcedownload'] = 1;
 785          }
 786          $url = new moodle_url($urlbase, $params);
 787          $url->set_slashargument($path);
 788          return $url;
 789      }
 790  
 791      /**
 792       * Factory method for creation of url pointing to plugin file.
 793       *
 794       * Please note this method can be used only from the plugins to
 795       * create urls of own files, it must not be used outside of plugins!
 796       *
 797       * @param int $contextid
 798       * @param string $component
 799       * @param string $area
 800       * @param int $itemid
 801       * @param string $pathname
 802       * @param string $filename
 803       * @param bool $forcedownload
 804       * @param mixed $includetoken Whether to use a user token when displaying this group image.
 805       *                True indicates to generate a token for current user, and integer value indicates to generate a token for the
 806       *                user whose id is the value indicated.
 807       *                If the group picture is included in an e-mail or some other location where the audience is a specific
 808       *                user who will not be logged in when viewing, then we use a token to authenticate the user.
 809       * @return moodle_url
 810       */
 811      public static function make_pluginfile_url($contextid, $component, $area, $itemid, $pathname, $filename,
 812                                                 $forcedownload = false, $includetoken = false) {
 813          global $CFG, $USER;
 814  
 815          $path = [];
 816  
 817          if ($includetoken) {
 818              $urlbase = "$CFG->wwwroot/tokenpluginfile.php";
 819              $userid = $includetoken === true ? $USER->id : $includetoken;
 820              $token = get_user_key('core_files', $userid);
 821              if ($CFG->slasharguments) {
 822                  $path[] = $token;
 823              }
 824          } else {
 825              $urlbase = "$CFG->wwwroot/pluginfile.php";
 826          }
 827          $path[] = $contextid;
 828          $path[] = $component;
 829          $path[] = $area;
 830  
 831          if ($itemid !== null) {
 832              $path[] = $itemid;
 833          }
 834  
 835          $path = "/" . implode('/', $path) . "{$pathname}{$filename}";
 836  
 837          $url = self::make_file_url($urlbase, $path, $forcedownload, $includetoken);
 838          if ($includetoken && empty($CFG->slasharguments)) {
 839              $url->param('token', $token);
 840          }
 841          return $url;
 842      }
 843  
 844      /**
 845       * Factory method for creation of url pointing to plugin file.
 846       * This method is the same that make_pluginfile_url but pointing to the webservice pluginfile.php script.
 847       * It should be used only in external functions.
 848       *
 849       * @since  2.8
 850       * @param int $contextid
 851       * @param string $component
 852       * @param string $area
 853       * @param int $itemid
 854       * @param string $pathname
 855       * @param string $filename
 856       * @param bool $forcedownload
 857       * @return moodle_url
 858       */
 859      public static function make_webservice_pluginfile_url($contextid, $component, $area, $itemid, $pathname, $filename,
 860                                                 $forcedownload = false) {
 861          global $CFG;
 862          $urlbase = "$CFG->wwwroot/webservice/pluginfile.php";
 863          if ($itemid === null) {
 864              return self::make_file_url($urlbase, "/$contextid/$component/$area".$pathname.$filename, $forcedownload);
 865          } else {
 866              return self::make_file_url($urlbase, "/$contextid/$component/$area/$itemid".$pathname.$filename, $forcedownload);
 867          }
 868      }
 869  
 870      /**
 871       * Factory method for creation of url pointing to draft file of current user.
 872       *
 873       * @param int $draftid draft item id
 874       * @param string $pathname
 875       * @param string $filename
 876       * @param bool $forcedownload
 877       * @return moodle_url
 878       */
 879      public static function make_draftfile_url($draftid, $pathname, $filename, $forcedownload = false) {
 880          global $CFG, $USER;
 881          $urlbase = "$CFG->wwwroot/draftfile.php";
 882          $context = context_user::instance($USER->id);
 883  
 884          return self::make_file_url($urlbase, "/$context->id/user/draft/$draftid".$pathname.$filename, $forcedownload);
 885      }
 886  
 887      /**
 888       * Factory method for creating of links to legacy course files.
 889       *
 890       * @param int $courseid
 891       * @param string $filepath
 892       * @param bool $forcedownload
 893       * @return moodle_url
 894       */
 895      public static function make_legacyfile_url($courseid, $filepath, $forcedownload = false) {
 896          global $CFG;
 897  
 898          $urlbase = "$CFG->wwwroot/file.php";
 899          return self::make_file_url($urlbase, '/'.$courseid.'/'.$filepath, $forcedownload);
 900      }
 901  
 902      /**
 903       * Checks if URL is relative to $CFG->wwwroot.
 904       *
 905       * @return bool True if URL is relative to $CFG->wwwroot; otherwise, false.
 906       */
 907      public function is_local_url() : bool {
 908          global $CFG;
 909  
 910          $url = $this->out();
 911          // Does URL start with wwwroot? Otherwise, URL isn't relative to wwwroot.
 912          return ( ($url === $CFG->wwwroot) || (strpos($url, $CFG->wwwroot.'/') === 0) );
 913      }
 914  
 915      /**
 916       * Returns URL as relative path from $CFG->wwwroot
 917       *
 918       * Can be used for passing around urls with the wwwroot stripped
 919       *
 920       * @param boolean $escaped Use &amp; as params separator instead of plain &
 921       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 922       * @return string Resulting URL
 923       * @throws coding_exception if called on a non-local url
 924       */
 925      public function out_as_local_url($escaped = true, array $overrideparams = null) {
 926          global $CFG;
 927  
 928          // URL should be relative to wwwroot. If not then throw exception.
 929          if ($this->is_local_url()) {
 930              $url = $this->out($escaped, $overrideparams);
 931              $localurl = substr($url, strlen($CFG->wwwroot));
 932              return !empty($localurl) ? $localurl : '';
 933          } else {
 934              throw new coding_exception('out_as_local_url called on a non-local URL');
 935          }
 936      }
 937  
 938      /**
 939       * Returns the 'path' portion of a URL. For example, if the URL is
 940       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 941       * return '/my/file/is/here.txt'.
 942       *
 943       * By default the path includes slash-arguments (for example,
 944       * '/myfile.php/extra/arguments') so it is what you would expect from a
 945       * URL path. If you don't want this behaviour, you can opt to exclude the
 946       * slash arguments. (Be careful: if the $CFG variable slasharguments is
 947       * disabled, these URLs will have a different format and you may need to
 948       * look at the 'file' parameter too.)
 949       *
 950       * @param bool $includeslashargument If true, includes slash arguments
 951       * @return string Path of URL
 952       */
 953      public function get_path($includeslashargument = true) {
 954          return $this->path . ($includeslashargument ? $this->slashargument : '');
 955      }
 956  
 957      /**
 958       * Returns a given parameter value from the URL.
 959       *
 960       * @param string $name Name of parameter
 961       * @return string Value of parameter or null if not set
 962       */
 963      public function get_param($name) {
 964          if (array_key_exists($name, $this->params)) {
 965              return $this->params[$name];
 966          } else {
 967              return null;
 968          }
 969      }
 970  
 971      /**
 972       * Returns the 'scheme' portion of a URL. For example, if the URL is
 973       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 974       * return 'http' (without the colon).
 975       *
 976       * @return string Scheme of the URL.
 977       */
 978      public function get_scheme() {
 979          return $this->scheme;
 980      }
 981  
 982      /**
 983       * Returns the 'host' portion of a URL. For example, if the URL is
 984       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 985       * return 'www.example.org'.
 986       *
 987       * @return string Host of the URL.
 988       */
 989      public function get_host() {
 990          return $this->host;
 991      }
 992  
 993      /**
 994       * Returns the 'port' portion of a URL. For example, if the URL is
 995       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 996       * return '447'.
 997       *
 998       * @return string Port of the URL.
 999       */
1000      public function get_port() {
1001          return $this->port;
1002      }
1003  }
1004  
1005  /**
1006   * Determine if there is data waiting to be processed from a form
1007   *
1008   * Used on most forms in Moodle to check for data
1009   * Returns the data as an object, if it's found.
1010   * This object can be used in foreach loops without
1011   * casting because it's cast to (array) automatically
1012   *
1013   * Checks that submitted POST data exists and returns it as object.
1014   *
1015   * @return mixed false or object
1016   */
1017  function data_submitted() {
1018  
1019      if (empty($_POST)) {
1020          return false;
1021      } else {
1022          return (object)fix_utf8($_POST);
1023      }
1024  }
1025  
1026  /**
1027   * Given some normal text this function will break up any
1028   * long words to a given size by inserting the given character
1029   *
1030   * It's multibyte savvy and doesn't change anything inside html tags.
1031   *
1032   * @param string $string the string to be modified
1033   * @param int $maxsize maximum length of the string to be returned
1034   * @param string $cutchar the string used to represent word breaks
1035   * @return string
1036   */
1037  function break_up_long_words($string, $maxsize=20, $cutchar=' ') {
1038  
1039      // First of all, save all the tags inside the text to skip them.
1040      $tags = array();
1041      filter_save_tags($string, $tags);
1042  
1043      // Process the string adding the cut when necessary.
1044      $output = '';
1045      $length = core_text::strlen($string);
1046      $wordlength = 0;
1047  
1048      for ($i=0; $i<$length; $i++) {
1049          $char = core_text::substr($string, $i, 1);
1050          if ($char == ' ' or $char == "\t" or $char == "\n" or $char == "\r" or $char == "<" or $char == ">") {
1051              $wordlength = 0;
1052          } else {
1053              $wordlength++;
1054              if ($wordlength > $maxsize) {
1055                  $output .= $cutchar;
1056                  $wordlength = 0;
1057              }
1058          }
1059          $output .= $char;
1060      }
1061  
1062      // Finally load the tags back again.
1063      if (!empty($tags)) {
1064          $output = str_replace(array_keys($tags), $tags, $output);
1065      }
1066  
1067      return $output;
1068  }
1069  
1070  /**
1071   * Try and close the current window using JavaScript, either immediately, or after a delay.
1072   *
1073   * Echo's out the resulting XHTML & javascript
1074   *
1075   * @param integer $delay a delay in seconds before closing the window. Default 0.
1076   * @param boolean $reloadopener if true, we will see if this window was a pop-up, and try
1077   *      to reload the parent window before this one closes.
1078   */
1079  function close_window($delay = 0, $reloadopener = false) {
1080      global $PAGE, $OUTPUT;
1081  
1082      if (!$PAGE->headerprinted) {
1083          $PAGE->set_title(get_string('closewindow'));
1084          echo $OUTPUT->header();
1085      } else {
1086          $OUTPUT->container_end_all(false);
1087      }
1088  
1089      if ($reloadopener) {
1090          // Trigger the reload immediately, even if the reload is after a delay.
1091          $PAGE->requires->js_function_call('window.opener.location.reload', array(true));
1092      }
1093      $OUTPUT->notification(get_string('windowclosing'), 'notifysuccess');
1094  
1095      $PAGE->requires->js_function_call('close_window', array(new stdClass()), false, $delay);
1096  
1097      echo $OUTPUT->footer();
1098      exit;
1099  }
1100  
1101  /**
1102   * Returns a string containing a link to the user documentation for the current page.
1103   *
1104   * Also contains an icon by default. Shown to teachers and admin only.
1105   *
1106   * @param string $text The text to be displayed for the link
1107   * @return string The link to user documentation for this current page
1108   */
1109  function page_doc_link($text='') {
1110      global $OUTPUT, $PAGE;
1111      $path = page_get_doc_link_path($PAGE);
1112      if (!$path) {
1113          return '';
1114      }
1115      return $OUTPUT->doc_link($path, $text);
1116  }
1117  
1118  /**
1119   * Returns the path to use when constructing a link to the docs.
1120   *
1121   * @since Moodle 2.5.1 2.6
1122   * @param moodle_page $page
1123   * @return string
1124   */
1125  function page_get_doc_link_path(moodle_page $page) {
1126      global $CFG;
1127  
1128      if (empty($CFG->docroot) || during_initial_install()) {
1129          return '';
1130      }
1131      if (!has_capability('moodle/site:doclinks', $page->context)) {
1132          return '';
1133      }
1134  
1135      $path = $page->docspath;
1136      if (!$path) {
1137          return '';
1138      }
1139      return $path;
1140  }
1141  
1142  
1143  /**
1144   * Validates an email to make sure it makes sense.
1145   *
1146   * @param string $address The email address to validate.
1147   * @return boolean
1148   */
1149  function validate_email($address) {
1150      global $CFG;
1151  
1152      if ($address === null || $address === false || $address === '') {
1153          return false;
1154      }
1155  
1156      require_once("{$CFG->libdir}/phpmailer/moodle_phpmailer.php");
1157  
1158      return moodle_phpmailer::validateAddress($address ?? '') && !preg_match('/[<>]/', $address);
1159  }
1160  
1161  /**
1162   * Extracts file argument either from file parameter or PATH_INFO
1163   *
1164   * Note: $scriptname parameter is not needed anymore
1165   *
1166   * @return string file path (only safe characters)
1167   */
1168  function get_file_argument() {
1169      global $SCRIPT;
1170  
1171      $relativepath = false;
1172      $hasforcedslashargs = false;
1173  
1174      if (isset($_SERVER['REQUEST_URI']) && !empty($_SERVER['REQUEST_URI'])) {
1175          // Checks whether $_SERVER['REQUEST_URI'] contains '/pluginfile.php/'
1176          // instead of '/pluginfile.php?', when serving a file from e.g. mod_imscp or mod_scorm.
1177          if ((strpos($_SERVER['REQUEST_URI'], '/pluginfile.php/') !== false)
1178                  && isset($_SERVER['PATH_INFO']) && !empty($_SERVER['PATH_INFO'])) {
1179              // Exclude edge cases like '/pluginfile.php/?file='.
1180              $args = explode('/', ltrim($_SERVER['PATH_INFO'], '/'));
1181              $hasforcedslashargs = (count($args) > 2); // Always at least: context, component and filearea.
1182          }
1183      }
1184      if (!$hasforcedslashargs) {
1185          $relativepath = optional_param('file', false, PARAM_PATH);
1186      }
1187  
1188      if ($relativepath !== false and $relativepath !== '') {
1189          return $relativepath;
1190      }
1191      $relativepath = false;
1192  
1193      // Then try extract file from the slasharguments.
1194      if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
1195          // NOTE: IIS tends to convert all file paths to single byte DOS encoding,
1196          //       we can not use other methods because they break unicode chars,
1197          //       the only ways are to use URL rewriting
1198          //       OR
1199          //       to properly set the 'FastCGIUtf8ServerVariables' registry key.
1200          if (isset($_SERVER['PATH_INFO']) and $_SERVER['PATH_INFO'] !== '') {
1201              // Check that PATH_INFO works == must not contain the script name.
1202              if (strpos($_SERVER['PATH_INFO'], $SCRIPT) === false) {
1203                  $relativepath = clean_param(urldecode($_SERVER['PATH_INFO']), PARAM_PATH);
1204              }
1205          }
1206      } else {
1207          // All other apache-like servers depend on PATH_INFO.
1208          if (isset($_SERVER['PATH_INFO'])) {
1209              if (isset($_SERVER['SCRIPT_NAME']) and strpos($_SERVER['PATH_INFO'], $_SERVER['SCRIPT_NAME']) === 0) {
1210                  $relativepath = substr($_SERVER['PATH_INFO'], strlen($_SERVER['SCRIPT_NAME']));
1211              } else {
1212                  $relativepath = $_SERVER['PATH_INFO'];
1213              }
1214              $relativepath = clean_param($relativepath, PARAM_PATH);
1215          }
1216      }
1217  
1218      return $relativepath;
1219  }
1220  
1221  /**
1222   * Just returns an array of text formats suitable for a popup menu
1223   *
1224   * @return array
1225   */
1226  function format_text_menu() {
1227      return array (FORMAT_MOODLE => get_string('formattext'),
1228                    FORMAT_HTML => get_string('formathtml'),
1229                    FORMAT_PLAIN => get_string('formatplain'),
1230                    FORMAT_MARKDOWN => get_string('formatmarkdown'));
1231  }
1232  
1233  /**
1234   * Given text in a variety of format codings, this function returns the text as safe HTML.
1235   *
1236   * This function should mainly be used for long strings like posts,
1237   * answers, glossary items etc. For short strings {@link format_string()}.
1238   *
1239   * <pre>
1240   * Options:
1241   *      trusted     :   If true the string won't be cleaned. Default false required noclean=true.
1242   *      noclean     :   If true the string won't be cleaned, unless $CFG->forceclean is set. Default false required trusted=true.
1243   *      nocache     :   If true the strign will not be cached and will be formatted every call. Default false.
1244   *      filter      :   If true the string will be run through applicable filters as well. Default true.
1245   *      para        :   If true then the returned string will be wrapped in div tags. Default true.
1246   *      newlines    :   If true then lines newline breaks will be converted to HTML newline breaks. Default true.
1247   *      context     :   The context that will be used for filtering.
1248   *      overflowdiv :   If set to true the formatted text will be encased in a div
1249   *                      with the class no-overflow before being returned. Default false.
1250   *      allowid     :   If true then id attributes will not be removed, even when
1251   *                      using htmlpurifier. Default false.
1252   *      blanktarget :   If true all <a> tags will have target="_blank" added unless target is explicitly specified.
1253   * </pre>
1254   *
1255   * @staticvar array $croncache
1256   * @param string $text The text to be formatted. This is raw text originally from user input.
1257   * @param int $format Identifier of the text format to be used
1258   *            [FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_MARKDOWN]
1259   * @param stdClass|array $options text formatting options
1260   * @param int $courseiddonotuse deprecated course id, use context option instead
1261   * @return string
1262   */
1263  function format_text($text, $format = FORMAT_MOODLE, $options = null, $courseiddonotuse = null) {
1264      global $CFG, $DB, $PAGE;
1265  
1266      if ($text === '' || is_null($text)) {
1267          // No need to do any filters and cleaning.
1268          return '';
1269      }
1270  
1271      if ($options instanceof \core\context) {
1272          // A common mistake has been to call this function with a context object.
1273          // This has never been expected, nor supported.
1274          debugging(
1275              'The options argument should not be a context object directly. ' .
1276                  ' Please pass an array with a context key instead.',
1277              DEBUG_DEVELOPER,
1278          );
1279          $options = ['context' => $options];
1280      }
1281  
1282      // Detach object, we can not modify it.
1283      $options = (array)$options;
1284  
1285      if (!isset($options['trusted'])) {
1286          $options['trusted'] = false;
1287      }
1288      if ($format == FORMAT_MARKDOWN) {
1289          // Markdown format cannot be trusted in trusttext areas,
1290          // because we do not know how to sanitise it before editing.
1291          $options['trusted'] = false;
1292      }
1293      if (!isset($options['noclean'])) {
1294          if ($options['trusted'] and trusttext_active()) {
1295              // No cleaning if text trusted and noclean not specified.
1296              $options['noclean'] = true;
1297          } else {
1298              $options['noclean'] = false;
1299          }
1300      }
1301      if (!empty($CFG->forceclean)) {
1302          // Whatever the caller claims, the admin wants all content cleaned anyway.
1303          $options['noclean'] = false;
1304      }
1305      if (!isset($options['nocache'])) {
1306          $options['nocache'] = false;
1307      }
1308      if (!isset($options['filter'])) {
1309          $options['filter'] = true;
1310      }
1311      if (!isset($options['para'])) {
1312          $options['para'] = true;
1313      }
1314      if (!isset($options['newlines'])) {
1315          $options['newlines'] = true;
1316      }
1317      if (!isset($options['overflowdiv'])) {
1318          $options['overflowdiv'] = false;
1319      }
1320      $options['blanktarget'] = !empty($options['blanktarget']);
1321  
1322      // Calculate best context.
1323      if (empty($CFG->version) or $CFG->version < 2013051400 or during_initial_install()) {
1324          // Do not filter anything during installation or before upgrade completes.
1325          $context = null;
1326  
1327      } else if (isset($options['context'])) { // First by explicit passed context option.
1328          if (is_object($options['context'])) {
1329              $context = $options['context'];
1330          } else {
1331              $context = context::instance_by_id($options['context']);
1332          }
1333      } else if ($courseiddonotuse) {
1334          // Legacy courseid.
1335          $context = context_course::instance($courseiddonotuse);
1336      } else {
1337          // Fallback to $PAGE->context this may be problematic in CLI and other non-standard pages :-(.
1338          $context = $PAGE->context;
1339      }
1340  
1341      if (!$context) {
1342          // Either install/upgrade or something has gone really wrong because context does not exist (yet?).
1343          $options['nocache'] = true;
1344          $options['filter']  = false;
1345      }
1346  
1347      if ($options['filter']) {
1348          $filtermanager = filter_manager::instance();
1349          $filtermanager->setup_page_for_filters($PAGE, $context); // Setup global stuff filters may have.
1350          $filteroptions = array(
1351              'originalformat' => $format,
1352              'noclean' => $options['noclean'],
1353          );
1354      } else {
1355          $filtermanager = new null_filter_manager();
1356          $filteroptions = array();
1357      }
1358  
1359      switch ($format) {
1360          case FORMAT_HTML:
1361              $filteroptions['stage'] = 'pre_format';
1362              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1363              // Text is already in HTML format, so just continue to the next filtering stage.
1364              $filteroptions['stage'] = 'pre_clean';
1365              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1366              if (!$options['noclean']) {
1367                  $text = clean_text($text, FORMAT_HTML, $options);
1368              }
1369              $filteroptions['stage'] = 'post_clean';
1370              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1371              break;
1372  
1373          case FORMAT_PLAIN:
1374              $text = s($text); // Cleans dangerous JS.
1375              $text = rebuildnolinktag($text);
1376              $text = str_replace('  ', '&nbsp; ', $text);
1377              $text = nl2br($text);
1378              break;
1379  
1380          case FORMAT_WIKI:
1381              // This format is deprecated.
1382              $text = '<p>NOTICE: Wiki-like formatting has been removed from Moodle.  You should not be seeing
1383                       this message as all texts should have been converted to Markdown format instead.
1384                       Please post a bug report to http://moodle.org/bugs with information about where you
1385                       saw this message.</p>'.s($text);
1386              break;
1387  
1388          case FORMAT_MARKDOWN:
1389              $filteroptions['stage'] = 'pre_format';
1390              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1391              $text = markdown_to_html($text);
1392              $filteroptions['stage'] = 'pre_clean';
1393              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1394              if (!$options['noclean']) {
1395                  $text = clean_text($text, FORMAT_HTML, $options);
1396              }
1397              $filteroptions['stage'] = 'post_clean';
1398              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1399              break;
1400  
1401          default:  // FORMAT_MOODLE or anything else.
1402              $filteroptions['stage'] = 'pre_format';
1403              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1404              $text = text_to_html($text, null, $options['para'], $options['newlines']);
1405              $filteroptions['stage'] = 'pre_clean';
1406              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1407              if (!$options['noclean']) {
1408                  $text = clean_text($text, FORMAT_HTML, $options);
1409              }
1410              $filteroptions['stage'] = 'post_clean';
1411              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1412              break;
1413      }
1414      if ($options['filter']) {
1415          // At this point there should not be any draftfile links any more,
1416          // this happens when developers forget to post process the text.
1417          // The only potential problem is that somebody might try to format
1418          // the text before storing into database which would be itself big bug..
1419          $text = str_replace("\"$CFG->wwwroot/draftfile.php", "\"$CFG->wwwroot/brokenfile.php#", $text);
1420  
1421          if ($CFG->debugdeveloper) {
1422              if (strpos($text, '@@PLUGINFILE@@/') !== false) {
1423                  debugging('Before calling format_text(), the content must be processed with file_rewrite_pluginfile_urls()',
1424                      DEBUG_DEVELOPER);
1425              }
1426          }
1427      }
1428  
1429      if (!empty($options['overflowdiv'])) {
1430          $text = html_writer::tag('div', $text, array('class' => 'no-overflow'));
1431      }
1432  
1433      if ($options['blanktarget']) {
1434          $domdoc = new DOMDocument();
1435          libxml_use_internal_errors(true);
1436          $domdoc->loadHTML('<?xml version="1.0" encoding="UTF-8" ?>' . $text);
1437          libxml_clear_errors();
1438          foreach ($domdoc->getElementsByTagName('a') as $link) {
1439              if ($link->hasAttribute('target') && strpos($link->getAttribute('target'), '_blank') === false) {
1440                  continue;
1441              }
1442              $link->setAttribute('target', '_blank');
1443              if (strpos($link->getAttribute('rel'), 'noreferrer') === false) {
1444                  $link->setAttribute('rel', trim($link->getAttribute('rel') . ' noreferrer'));
1445              }
1446          }
1447  
1448          // This regex is nasty and I don't like it. The correct way to solve this is by loading the HTML like so:
1449          // $domdoc->loadHTML($text, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD); however it seems like some libxml
1450          // versions don't work properly and end up leaving <html><body>, so I'm forced to use
1451          // this regex to remove those tags as a preventive measure.
1452          $text = trim(preg_replace('~<(?:!DOCTYPE|/?(?:html|body))[^>]*>\s*~i', '', $domdoc->saveHTML($domdoc->documentElement)));
1453      }
1454  
1455      return $text;
1456  }
1457  
1458  /**
1459   * Resets some data related to filters, called during upgrade or when general filter settings change.
1460   *
1461   * @param bool $phpunitreset true means called from our PHPUnit integration test reset
1462   * @return void
1463   */
1464  function reset_text_filters_cache($phpunitreset = false) {
1465      global $CFG, $DB;
1466  
1467      if ($phpunitreset) {
1468          // HTMLPurifier does not change, DB is already reset to defaults,
1469          // nothing to do here, the dataroot was cleared too.
1470          return;
1471      }
1472  
1473      // The purge_all_caches() deals with cachedir and localcachedir purging,
1474      // the individual filter caches are invalidated as necessary elsewhere.
1475  
1476      // Update $CFG->filterall cache flag.
1477      if (empty($CFG->stringfilters)) {
1478          set_config('filterall', 0);
1479          return;
1480      }
1481      $installedfilters = core_component::get_plugin_list('filter');
1482      $filters = explode(',', $CFG->stringfilters);
1483      foreach ($filters as $filter) {
1484          if (isset($installedfilters[$filter])) {
1485              set_config('filterall', 1);
1486              return;
1487          }
1488      }
1489      set_config('filterall', 0);
1490  }
1491  
1492  /**
1493   * Given a simple string, this function returns the string
1494   * processed by enabled string filters if $CFG->filterall is enabled
1495   *
1496   * This function should be used to print short strings (non html) that
1497   * need filter processing e.g. activity titles, post subjects,
1498   * glossary concepts.
1499   *
1500   * @staticvar bool $strcache
1501   * @param string $string The string to be filtered. Should be plain text, expect
1502   * possibly for multilang tags.
1503   * @param boolean $striplinks To strip any link in the result text. Moodle 1.8 default changed from false to true! MDL-8713
1504   * @param array $options options array/object or courseid
1505   * @return string
1506   */
1507  function format_string($string, $striplinks = true, $options = null) {
1508      global $CFG, $PAGE;
1509  
1510      if ($string === '' || is_null($string)) {
1511          // No need to do any filters and cleaning.
1512          return '';
1513      }
1514  
1515      // We'll use a in-memory cache here to speed up repeated strings.
1516      static $strcache = false;
1517  
1518      if (empty($CFG->version) or $CFG->version < 2013051400 or during_initial_install()) {
1519          // Do not filter anything during installation or before upgrade completes.
1520          return $string = strip_tags($string);
1521      }
1522  
1523      if ($strcache === false or count($strcache) > 2000) {
1524          // This number might need some tuning to limit memory usage in cron.
1525          $strcache = array();
1526      }
1527  
1528      // This method only expects either:
1529      // - an array of options;
1530      // - a stdClass of options to be cast to an array; or
1531      // - an integer courseid.
1532      if ($options === null) {
1533          $options = [];
1534      } else if (is_numeric($options)) {
1535          // Legacy courseid usage.
1536          $options  = ['context' => \core\context\course::instance($options)];
1537      } else if ($options instanceof \core\context) {
1538          // A common mistake has been to call this function with a context object.
1539          // This has never been expected, or nor supported.
1540          debugging(
1541              'The options argument should not be a context object directly. ' .
1542                  ' Please pass an array with a context key instead.',
1543              DEBUG_DEVELOPER,
1544          );
1545          $options = ['context' => $options];
1546      } else if (is_array($options) || is_a($options, \stdClass::class)) {
1547          // Re-cast to array to prevent modifications to the original object.
1548          $options = (array) $options;
1549      } else {
1550          // Something else was passed, so we'll just use an empty array.
1551          // Attempt to cast to array since we always used to, but throw in some debugging.
1552          debugging(sprintf(
1553              'The options argument should be an Array, or stdclass. %s passed.',
1554              gettype($options),
1555          ), DEBUG_DEVELOPER);
1556          $options = (array) $options;
1557      }
1558  
1559      if (empty($options['context'])) {
1560          // Fallback to $PAGE->context this may be problematic in CLI and other non-standard pages :-(.
1561          $options['context'] = $PAGE->context;
1562      } else if (is_numeric($options['context'])) {
1563          $options['context'] = context::instance_by_id($options['context']);
1564      }
1565      if (!isset($options['filter'])) {
1566          $options['filter'] = true;
1567      }
1568  
1569      $options['escape'] = !isset($options['escape']) || $options['escape'];
1570  
1571      if (!$options['context']) {
1572          // We did not find any context? weird.
1573          return $string = strip_tags($string);
1574      }
1575  
1576      // Calculate md5.
1577      $cachekeys = array($string, $striplinks, $options['context']->id,
1578          $options['escape'], current_language(), $options['filter']);
1579      $md5 = md5(implode('<+>', $cachekeys));
1580  
1581      // Fetch from cache if possible.
1582      if (isset($strcache[$md5])) {
1583          return $strcache[$md5];
1584      }
1585  
1586      // First replace all ampersands not followed by html entity code
1587      // Regular expression moved to its own method for easier unit testing.
1588      $string = $options['escape'] ? replace_ampersands_not_followed_by_entity($string) : $string;
1589  
1590      if (!empty($CFG->filterall) && $options['filter']) {
1591          $filtermanager = filter_manager::instance();
1592          $filtermanager->setup_page_for_filters($PAGE, $options['context']); // Setup global stuff filters may have.
1593          $string = $filtermanager->filter_string($string, $options['context']);
1594      }
1595  
1596      // If the site requires it, strip ALL tags from this string.
1597      if (!empty($CFG->formatstringstriptags)) {
1598          if ($options['escape']) {
1599              $string = str_replace(array('<', '>'), array('&lt;', '&gt;'), strip_tags($string));
1600          } else {
1601              $string = strip_tags($string);
1602          }
1603      } else {
1604          // Otherwise strip just links if that is required (default).
1605          if ($striplinks) {
1606              // Strip links in string.
1607              $string = strip_links($string);
1608          }
1609          $string = clean_text($string);
1610      }
1611  
1612      // Store to cache.
1613      $strcache[$md5] = $string;
1614  
1615      return $string;
1616  }
1617  
1618  /**
1619   * Given a string, performs a negative lookahead looking for any ampersand character
1620   * that is not followed by a proper HTML entity. If any is found, it is replaced
1621   * by &amp;. The string is then returned.
1622   *
1623   * @param string $string
1624   * @return string
1625   */
1626  function replace_ampersands_not_followed_by_entity($string) {
1627      return preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&amp;", $string ?? '');
1628  }
1629  
1630  /**
1631   * Given a string, replaces all <a>.*</a> by .* and returns the string.
1632   *
1633   * @param string $string
1634   * @return string
1635   */
1636  function strip_links($string) {
1637      return preg_replace('/(<a\s[^>]+?>)(.+?)(<\/a>)/is', '$2', $string);
1638  }
1639  
1640  /**
1641   * This expression turns links into something nice in a text format. (Russell Jungwirth)
1642   *
1643   * @param string $string
1644   * @return string
1645   */
1646  function wikify_links($string) {
1647      return preg_replace('~(<a [^<]*href=["|\']?([^ "\']*)["|\']?[^>]*>([^<]*)</a>)~i', '$3 [ $2 ]', $string);
1648  }
1649  
1650  /**
1651   * Given text in a variety of format codings, this function returns the text as plain text suitable for plain email.
1652   *
1653   * @param string $text The text to be formatted. This is raw text originally from user input.
1654   * @param int $format Identifier of the text format to be used
1655   *            [FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_WIKI, FORMAT_MARKDOWN]
1656   * @return string
1657   */
1658  function format_text_email($text, $format) {
1659  
1660      switch ($format) {
1661  
1662          case FORMAT_PLAIN:
1663              return $text;
1664              break;
1665  
1666          case FORMAT_WIKI:
1667              // There should not be any of these any more!
1668              $text = wikify_links($text);
1669              return core_text::entities_to_utf8(strip_tags($text), true);
1670              break;
1671  
1672          case FORMAT_HTML:
1673              return html_to_text($text);
1674              break;
1675  
1676          case FORMAT_MOODLE:
1677          case FORMAT_MARKDOWN:
1678          default:
1679              $text = wikify_links($text);
1680              return core_text::entities_to_utf8(strip_tags($text), true);
1681              break;
1682      }
1683  }
1684  
1685  /**
1686   * Formats activity intro text
1687   *
1688   * @param string $module name of module
1689   * @param object $activity instance of activity
1690   * @param int $cmid course module id
1691   * @param bool $filter filter resulting html text
1692   * @return string
1693   */
1694  function format_module_intro($module, $activity, $cmid, $filter=true) {
1695      global $CFG;
1696      require_once("$CFG->libdir/filelib.php");
1697      $context = context_module::instance($cmid);
1698      $options = array('noclean' => true, 'para' => false, 'filter' => $filter, 'context' => $context, 'overflowdiv' => true);
1699      $intro = file_rewrite_pluginfile_urls($activity->intro, 'pluginfile.php', $context->id, 'mod_'.$module, 'intro', null);
1700      return trim(format_text($intro, $activity->introformat, $options, null));
1701  }
1702  
1703  /**
1704   * Removes the usage of Moodle files from a text.
1705   *
1706   * In some rare cases we need to re-use a text that already has embedded links
1707   * to some files hosted within Moodle. But the new area in which we will push
1708   * this content does not support files... therefore we need to remove those files.
1709   *
1710   * @param string $source The text
1711   * @return string The stripped text
1712   */
1713  function strip_pluginfile_content($source) {
1714      $baseurl = '@@PLUGINFILE@@';
1715      // Looking for something like < .* "@@pluginfile@@.*" .* >
1716      $pattern = '$<[^<>]+["\']' . $baseurl . '[^"\']*["\'][^<>]*>$';
1717      $stripped = preg_replace($pattern, '', $source);
1718      // Use purify html to rebalence potentially mismatched tags and generally cleanup.
1719      return purify_html($stripped);
1720  }
1721  
1722  /**
1723   * Legacy function, used for cleaning of old forum and glossary text only.
1724   *
1725   * @param string $text text that may contain legacy TRUSTTEXT marker
1726   * @return string text without legacy TRUSTTEXT marker
1727   */
1728  function trusttext_strip($text) {
1729      if (!is_string($text)) {
1730          // This avoids the potential for an endless loop below.
1731          throw new coding_exception('trusttext_strip parameter must be a string');
1732      }
1733      while (true) { // Removing nested TRUSTTEXT.
1734          $orig = $text;
1735          $text = str_replace('#####TRUSTTEXT#####', '', $text);
1736          if (strcmp($orig, $text) === 0) {
1737              return $text;
1738          }
1739      }
1740  }
1741  
1742  /**
1743   * Must be called before editing of all texts with trust flag. Removes all XSS nasties from texts stored in database if needed.
1744   *
1745   * @param stdClass $object data object with xxx, xxxformat and xxxtrust fields
1746   * @param string $field name of text field
1747   * @param context $context active context
1748   * @return stdClass updated $object
1749   */
1750  function trusttext_pre_edit($object, $field, $context) {
1751      $trustfield  = $field.'trust';
1752      $formatfield = $field.'format';
1753  
1754      if ($object->$formatfield == FORMAT_MARKDOWN) {
1755          // We do not have a way to sanitise Markdown texts,
1756          // luckily editors for this format should not have XSS problems.
1757          return $object;
1758      }
1759  
1760      if (!$object->$trustfield or !trusttext_trusted($context)) {
1761          $object->$field = clean_text($object->$field, $object->$formatfield);
1762      }
1763  
1764      return $object;
1765  }
1766  
1767  /**
1768   * Is current user trusted to enter no dangerous XSS in this context?
1769   *
1770   * Please note the user must be in fact trusted everywhere on this server!!
1771   *
1772   * @param context $context
1773   * @return bool true if user trusted
1774   */
1775  function trusttext_trusted($context) {
1776      return (trusttext_active() and has_capability('moodle/site:trustcontent', $context));
1777  }
1778  
1779  /**
1780   * Is trusttext feature active?
1781   *
1782   * @return bool
1783   */
1784  function trusttext_active() {
1785      global $CFG;
1786  
1787      return !empty($CFG->enabletrusttext);
1788  }
1789  
1790  /**
1791   * Cleans raw text removing nasties.
1792   *
1793   * Given raw text (eg typed in by a user) this function cleans it up and removes any nasty tags that could mess up
1794   * Moodle pages through XSS attacks.
1795   *
1796   * The result must be used as a HTML text fragment, this function can not cleanup random
1797   * parts of html tags such as url or src attributes.
1798   *
1799   * NOTE: the format parameter was deprecated because we can safely clean only HTML.
1800   *
1801   * @param string $text The text to be cleaned
1802   * @param int|string $format deprecated parameter, should always contain FORMAT_HTML or FORMAT_MOODLE
1803   * @param array $options Array of options; currently only option supported is 'allowid' (if true,
1804   *   does not remove id attributes when cleaning)
1805   * @return string The cleaned up text
1806   */
1807  function clean_text($text, $format = FORMAT_HTML, $options = array()) {
1808      $text = (string)$text;
1809  
1810      if ($format != FORMAT_HTML and $format != FORMAT_HTML) {
1811          // TODO: we need to standardise cleanup of text when loading it into editor first.
1812          // debugging('clean_text() is designed to work only with html');.
1813      }
1814  
1815      if ($format == FORMAT_PLAIN) {
1816          return $text;
1817      }
1818  
1819      if (is_purify_html_necessary($text)) {
1820          $text = purify_html($text, $options);
1821      }
1822  
1823      // Originally we tried to neutralise some script events here, it was a wrong approach because
1824      // it was trivial to work around that (for example using style based XSS exploits).
1825      // We must not give false sense of security here - all developers MUST understand how to use
1826      // rawurlencode(), htmlentities(), htmlspecialchars(), p(), s(), moodle_url, html_writer and friends!!!
1827  
1828      return $text;
1829  }
1830  
1831  /**
1832   * Is it necessary to use HTMLPurifier?
1833   *
1834   * @private
1835   * @param string $text
1836   * @return bool false means html is safe and valid, true means use HTMLPurifier
1837   */
1838  function is_purify_html_necessary($text) {
1839      if ($text === '') {
1840          return false;
1841      }
1842  
1843      if ($text === (string)((int)$text)) {
1844          return false;
1845      }
1846  
1847      if (strpos($text, '&') !== false or preg_match('|<[^pesb/]|', $text)) {
1848          // We need to normalise entities or other tags except p, em, strong and br present.
1849          return true;
1850      }
1851  
1852      $altered = htmlspecialchars($text, ENT_NOQUOTES, 'UTF-8', true);
1853      if ($altered === $text) {
1854          // No < > or other special chars means this must be safe.
1855          return false;
1856      }
1857  
1858      // Let's try to convert back some safe html tags.
1859      $altered = preg_replace('|&lt;p&gt;(.*?)&lt;/p&gt;|m', '<p>$1</p>', $altered);
1860      if ($altered === $text) {
1861          return false;
1862      }
1863      $altered = preg_replace('|&lt;em&gt;([^<>]+?)&lt;/em&gt;|m', '<em>$1</em>', $altered);
1864      if ($altered === $text) {
1865          return false;
1866      }
1867      $altered = preg_replace('|&lt;strong&gt;([^<>]+?)&lt;/strong&gt;|m', '<strong>$1</strong>', $altered);
1868      if ($altered === $text) {
1869          return false;
1870      }
1871      $altered = str_replace('&lt;br /&gt;', '<br />', $altered);
1872      if ($altered === $text) {
1873          return false;
1874      }
1875  
1876      return true;
1877  }
1878  
1879  /**
1880   * KSES replacement cleaning function - uses HTML Purifier.
1881   *
1882   * @param string $text The (X)HTML string to purify
1883   * @param array $options Array of options; currently only option supported is 'allowid' (if set,
1884   *   does not remove id attributes when cleaning)
1885   * @return string
1886   */
1887  function purify_html($text, $options = array()) {
1888      global $CFG;
1889  
1890      $text = (string)$text;
1891  
1892      static $purifiers = array();
1893      static $caches = array();
1894  
1895      // Purifier code can change only during major version upgrade.
1896      $version = empty($CFG->version) ? 0 : $CFG->version;
1897      $cachedir = "$CFG->localcachedir/htmlpurifier/$version";
1898      if (!file_exists($cachedir)) {
1899          // Purging of caches may remove the cache dir at any time,
1900          // luckily file_exists() results should be cached for all existing directories.
1901          $purifiers = array();
1902          $caches = array();
1903          gc_collect_cycles();
1904  
1905          make_localcache_directory('htmlpurifier', false);
1906          check_dir_exists($cachedir);
1907      }
1908  
1909      $allowid = empty($options['allowid']) ? 0 : 1;
1910      $allowobjectembed = empty($CFG->allowobjectembed) ? 0 : 1;
1911  
1912      $type = 'type_'.$allowid.'_'.$allowobjectembed;
1913  
1914      if (!array_key_exists($type, $caches)) {
1915          $caches[$type] = cache::make('core', 'htmlpurifier', array('type' => $type));
1916      }
1917      $cache = $caches[$type];
1918  
1919      // Add revision number and all options to the text key so that it is compatible with local cluster node caches.
1920      $key = "|$version|$allowobjectembed|$allowid|$text";
1921      $filteredtext = $cache->get($key);
1922  
1923      if ($filteredtext === true) {
1924          // The filtering did not change the text last time, no need to filter anything again.
1925          return $text;
1926      } else if ($filteredtext !== false) {
1927          return $filteredtext;
1928      }
1929  
1930      if (empty($purifiers[$type])) {
1931          require_once $CFG->libdir.'/htmlpurifier/HTMLPurifier.safe-includes.php';
1932          require_once $CFG->libdir.'/htmlpurifier/locallib.php';
1933          $config = HTMLPurifier_Config::createDefault();
1934  
1935          $config->set('HTML.DefinitionID', 'moodlehtml');
1936          $config->set('HTML.DefinitionRev', 7);
1937          $config->set('Cache.SerializerPath', $cachedir);
1938          $config->set('Cache.SerializerPermissions', $CFG->directorypermissions);
1939          $config->set('Core.NormalizeNewlines', false);
1940          $config->set('Core.ConvertDocumentToFragment', true);
1941          $config->set('Core.Encoding', 'UTF-8');
1942          $config->set('HTML.Doctype', 'XHTML 1.0 Transitional');
1943          $config->set('URI.AllowedSchemes', array(
1944              'http' => true,
1945              'https' => true,
1946              'ftp' => true,
1947              'irc' => true,
1948              'nntp' => true,
1949              'news' => true,
1950              'rtsp' => true,
1951              'rtmp' => true,
1952              'teamspeak' => true,
1953              'gopher' => true,
1954              'mms' => true,
1955              'mailto' => true
1956          ));
1957          $config->set('Attr.AllowedFrameTargets', array('_blank'));
1958  
1959          if ($allowobjectembed) {
1960              $config->set('HTML.SafeObject', true);
1961              $config->set('Output.FlashCompat', true);
1962              $config->set('HTML.SafeEmbed', true);
1963          }
1964  
1965          if ($allowid) {
1966              $config->set('Attr.EnableID', true);
1967          }
1968  
1969          if ($def = $config->maybeGetRawHTMLDefinition()) {
1970              $def->addElement('nolink', 'Inline', 'Flow', array());                      // Skip our filters inside.
1971              $def->addElement('tex', 'Inline', 'Inline', array());                       // Tex syntax, equivalent to $$xx$$.
1972              $def->addElement('algebra', 'Inline', 'Inline', array());                   // Algebra syntax, equivalent to @@xx@@.
1973              $def->addElement('lang', 'Block', 'Flow', array(), array('lang'=>'CDATA')); // Original multilang style - only our hacked lang attribute.
1974              $def->addAttribute('span', 'xxxlang', 'CDATA');                             // Current very problematic multilang.
1975              // Enable the bidirectional isolate element and its span equivalent.
1976              $def->addElement('bdi', 'Inline', 'Flow', 'Common');
1977              $def->addAttribute('span', 'dir', 'Enum#ltr,rtl,auto');
1978  
1979              // Media elements.
1980              // https://html.spec.whatwg.org/#the-video-element
1981              $def->addElement('video', 'Inline', 'Optional: #PCDATA | Flow | source | track', 'Common', [
1982                  'src' => 'URI',
1983                  'crossorigin' => 'Enum#anonymous,use-credentials',
1984                  'poster' => 'URI',
1985                  'preload' => 'Enum#auto,metadata,none',
1986                  'autoplay' => 'Bool',
1987                  'playsinline' => 'Bool',
1988                  'loop' => 'Bool',
1989                  'muted' => 'Bool',
1990                  'controls' => 'Bool',
1991                  'width' => 'Length',
1992                  'height' => 'Length',
1993              ]);
1994              // https://html.spec.whatwg.org/#the-audio-element
1995              $def->addElement('audio', 'Inline', 'Optional: #PCDATA | Flow | source | track', 'Common', [
1996                  'src' => 'URI',
1997                  'crossorigin' => 'Enum#anonymous,use-credentials',
1998                  'preload' => 'Enum#auto,metadata,none',
1999                  'autoplay' => 'Bool',
2000                  'loop' => 'Bool',
2001                  'muted' => 'Bool',
2002                  'controls' => 'Bool'
2003              ]);
2004              // https://html.spec.whatwg.org/#the-source-element
2005              $def->addElement('source', false, 'Empty', null, [
2006                  'src' => 'URI',
2007                  'type' => 'Text'
2008              ]);
2009              // https://html.spec.whatwg.org/#the-track-element
2010              $def->addElement('track', false, 'Empty', null, [
2011                  'src' => 'URI',
2012                  'kind' => 'Enum#subtitles,captions,descriptions,chapters,metadata',
2013                  'srclang' => 'Text',
2014                  'label' => 'Text',
2015                  'default' => 'Bool',
2016              ]);
2017  
2018              // Use the built-in Ruby module to add annotation support.
2019              $def->manager->addModule(new HTMLPurifier_HTMLModule_Ruby());
2020          }
2021  
2022          $purifier = new HTMLPurifier($config);
2023          $purifiers[$type] = $purifier;
2024      } else {
2025          $purifier = $purifiers[$type];
2026      }
2027  
2028      $multilang = (strpos($text, 'class="multilang"') !== false);
2029  
2030      $filteredtext = $text;
2031      if ($multilang) {
2032          $filteredtextregex = '/<span(\s+lang="([a-zA-Z0-9_-]+)"|\s+class="multilang"){2}\s*>/';
2033          $filteredtext = preg_replace($filteredtextregex, '<span xxxlang="$2}">', $filteredtext);
2034      }
2035      $filteredtext = (string)$purifier->purify($filteredtext);
2036      if ($multilang) {
2037          $filteredtext = preg_replace('/<span xxxlang="([a-zA-Z0-9_-]+)">/', '<span lang="$1}" class="multilang">', $filteredtext);
2038      }
2039  
2040      if ($text === $filteredtext) {
2041          // No need to store the filtered text, next time we will just return unfiltered text
2042          // because it was not changed by purifying.
2043          $cache->set($key, true);
2044      } else {
2045          $cache->set($key, $filteredtext);
2046      }
2047  
2048      return $filteredtext;
2049  }
2050  
2051  /**
2052   * Given plain text, makes it into HTML as nicely as possible.
2053   *
2054   * May contain HTML tags already.
2055   *
2056   * Do not abuse this function. It is intended as lower level formatting feature used
2057   * by {@link format_text()} to convert FORMAT_MOODLE to HTML. You are supposed
2058   * to call format_text() in most of cases.
2059   *
2060   * @param string $text The string to convert.
2061   * @param boolean $smileyignored Was used to determine if smiley characters should convert to smiley images, ignored now
2062   * @param boolean $para If true then the returned string will be wrapped in div tags
2063   * @param boolean $newlines If true then lines newline breaks will be converted to HTML newline breaks.
2064   * @return string
2065   */
2066  function text_to_html($text, $smileyignored = null, $para = true, $newlines = true) {
2067      // Remove any whitespace that may be between HTML tags.
2068      $text = preg_replace("~>([[:space:]]+)<~i", "><", $text);
2069  
2070      // Remove any returns that precede or follow HTML tags.
2071      $text = preg_replace("~([\n\r])<~i", " <", $text);
2072      $text = preg_replace("~>([\n\r])~i", "> ", $text);
2073  
2074      // Make returns into HTML newlines.
2075      if ($newlines) {
2076          $text = nl2br($text);
2077      }
2078  
2079      // Wrap the whole thing in a div if required.
2080      if ($para) {
2081          // In 1.9 this was changed from a p => div.
2082          return '<div class="text_to_html">'.$text.'</div>';
2083      } else {
2084          return $text;
2085      }
2086  }
2087  
2088  /**
2089   * Given Markdown formatted text, make it into XHTML using external function
2090   *
2091   * @param string $text The markdown formatted text to be converted.
2092   * @return string Converted text
2093   */
2094  function markdown_to_html($text) {
2095      global $CFG;
2096  
2097      if ($text === '' or $text === null) {
2098          return $text;
2099      }
2100  
2101      require_once($CFG->libdir .'/markdown/MarkdownInterface.php');
2102      require_once($CFG->libdir .'/markdown/Markdown.php');
2103      require_once($CFG->libdir .'/markdown/MarkdownExtra.php');
2104  
2105      return \Michelf\MarkdownExtra::defaultTransform($text);
2106  }
2107  
2108  /**
2109   * Given HTML text, make it into plain text using external function
2110   *
2111   * @param string $html The text to be converted.
2112   * @param integer $width Width to wrap the text at. (optional, default 75 which
2113   *      is a good value for email. 0 means do not limit line length.)
2114   * @param boolean $dolinks By default, any links in the HTML are collected, and
2115   *      printed as a list at the end of the HTML. If you don't want that, set this
2116   *      argument to false.
2117   * @return string plain text equivalent of the HTML.
2118   */
2119  function html_to_text($html, $width = 75, $dolinks = true) {
2120      global $CFG;
2121  
2122      require_once($CFG->libdir .'/html2text/lib.php');
2123  
2124      $options = array(
2125          'width'     => $width,
2126          'do_links'  => 'table',
2127      );
2128  
2129      if (empty($dolinks)) {
2130          $options['do_links'] = 'none';
2131      }
2132      $h2t = new core_html2text($html, $options);
2133      $result = $h2t->getText();
2134  
2135      return $result;
2136  }
2137  
2138  /**
2139   * Converts texts or strings to plain text.
2140   *
2141   * - When used to convert user input introduced in an editor the text format needs to be passed in $contentformat like we usually
2142   *   do in format_text.
2143   * - When this function is used for strings that are usually passed through format_string before displaying them
2144   *   we need to set $contentformat to false. This will execute html_to_text as these strings can contain multilang tags if
2145   *   multilang filter is applied to headings.
2146   *
2147   * @param string $content The text as entered by the user
2148   * @param int|false $contentformat False for strings or the text format: FORMAT_MOODLE/FORMAT_HTML/FORMAT_PLAIN/FORMAT_MARKDOWN
2149   * @return string Plain text.
2150   */
2151  function content_to_text($content, $contentformat) {
2152  
2153      switch ($contentformat) {
2154          case FORMAT_PLAIN:
2155              // Nothing here.
2156              break;
2157          case FORMAT_MARKDOWN:
2158              $content = markdown_to_html($content);
2159              $content = html_to_text($content, 75, false);
2160              break;
2161          default:
2162              // FORMAT_HTML, FORMAT_MOODLE and $contentformat = false, the later one are strings usually formatted through
2163              // format_string, we need to convert them from html because they can contain HTML (multilang filter).
2164              $content = html_to_text($content, 75, false);
2165      }
2166  
2167      return trim($content, "\r\n ");
2168  }
2169  
2170  /**
2171   * Factory method for extracting draft file links from arbitrary text using regular expressions. Only text
2172   * is required; other file fields may be passed to filter.
2173   *
2174   * @param string $text Some html content.
2175   * @param bool $forcehttps force https urls.
2176   * @param int $contextid This parameter and the next three identify the file area to save to.
2177   * @param string $component The component name.
2178   * @param string $filearea The filearea.
2179   * @param int $itemid The item id for the filearea.
2180   * @param string $filename The specific filename of the file.
2181   * @return array
2182   */
2183  function extract_draft_file_urls_from_text($text, $forcehttps = false, $contextid = null, $component = null,
2184                                             $filearea = null, $itemid = null, $filename = null) {
2185      global $CFG;
2186  
2187      $wwwroot = $CFG->wwwroot;
2188      if ($forcehttps) {
2189          $wwwroot = str_replace('http://', 'https://', $wwwroot);
2190      }
2191      $urlstring = '/' . preg_quote($wwwroot, '/');
2192  
2193      $urlbase = preg_quote('draftfile.php');
2194      $urlstring .= "\/(?<urlbase>{$urlbase})";
2195  
2196      if (is_null($contextid)) {
2197          $contextid = '[0-9]+';
2198      }
2199      $urlstring .= "\/(?<contextid>{$contextid})";
2200  
2201      if (is_null($component)) {
2202          $component = '[a-z_]+';
2203      }
2204      $urlstring .= "\/(?<component>{$component})";
2205  
2206      if (is_null($filearea)) {
2207          $filearea = '[a-z_]+';
2208      }
2209      $urlstring .= "\/(?<filearea>{$filearea})";
2210  
2211      if (is_null($itemid)) {
2212          $itemid = '[0-9]+';
2213      }
2214      $urlstring .= "\/(?<itemid>{$itemid})";
2215  
2216      // Filename matching magic based on file_rewrite_urls_to_pluginfile().
2217      if (is_null($filename)) {
2218          $filename = '[^\'\",&<>|`\s:\\\\]+';
2219      }
2220      $urlstring .= "\/(?<filename>{$filename})/";
2221  
2222      // Regular expression which matches URLs and returns their components.
2223      preg_match_all($urlstring, $text, $urls, PREG_SET_ORDER);
2224      return $urls;
2225  }
2226  
2227  /**
2228   * This function will highlight search words in a given string
2229   *
2230   * It cares about HTML and will not ruin links.  It's best to use
2231   * this function after performing any conversions to HTML.
2232   *
2233   * @param string $needle The search string. Syntax like "word1 +word2 -word3" is dealt with correctly.
2234   * @param string $haystack The string (HTML) within which to highlight the search terms.
2235   * @param boolean $matchcase whether to do case-sensitive. Default case-insensitive.
2236   * @param string $prefix the string to put before each search term found.
2237   * @param string $suffix the string to put after each search term found.
2238   * @return string The highlighted HTML.
2239   */
2240  function highlight($needle, $haystack, $matchcase = false,
2241          $prefix = '<span class="highlight">', $suffix = '</span>') {
2242  
2243      // Quick bail-out in trivial cases.
2244      if (empty($needle) or empty($haystack)) {
2245          return $haystack;
2246      }
2247  
2248      // Break up the search term into words, discard any -words and build a regexp.
2249      $words = preg_split('/ +/', trim($needle));
2250      foreach ($words as $index => $word) {
2251          if (strpos($word, '-') === 0) {
2252              unset($words[$index]);
2253          } else if (strpos($word, '+') === 0) {
2254              $words[$index] = '\b' . preg_quote(ltrim($word, '+'), '/') . '\b'; // Match only as a complete word.
2255          } else {
2256              $words[$index] = preg_quote($word, '/');
2257          }
2258      }
2259      $regexp = '/(' . implode('|', $words) . ')/u'; // Char u is to do UTF-8 matching.
2260      if (!$matchcase) {
2261          $regexp .= 'i';
2262      }
2263  
2264      // Another chance to bail-out if $search was only -words.
2265      if (empty($words)) {
2266          return $haystack;
2267      }
2268  
2269      // Split the string into HTML tags and real content.
2270      $chunks = preg_split('/((?:<[^>]*>)+)/', $haystack, -1, PREG_SPLIT_DELIM_CAPTURE);
2271  
2272      // We have an array of alternating blocks of text, then HTML tags, then text, ...
2273      // Loop through replacing search terms in the text, and leaving the HTML unchanged.
2274      $ishtmlchunk = false;
2275      $result = '';
2276      foreach ($chunks as $chunk) {
2277          if ($ishtmlchunk) {
2278              $result .= $chunk;
2279          } else {
2280              $result .= preg_replace($regexp, $prefix . '$1' . $suffix, $chunk);
2281          }
2282          $ishtmlchunk = !$ishtmlchunk;
2283      }
2284  
2285      return $result;
2286  }
2287  
2288  /**
2289   * This function will highlight instances of $needle in $haystack
2290   *
2291   * It's faster that the above function {@link highlight()} and doesn't care about
2292   * HTML or anything.
2293   *
2294   * @param string $needle The string to search for
2295   * @param string $haystack The string to search for $needle in
2296   * @return string The highlighted HTML
2297   */
2298  function highlightfast($needle, $haystack) {
2299  
2300      if (empty($needle) or empty($haystack)) {
2301          return $haystack;
2302      }
2303  
2304      $parts = explode(core_text::strtolower($needle), core_text::strtolower($haystack));
2305  
2306      if (count($parts) === 1) {
2307          return $haystack;
2308      }
2309  
2310      $pos = 0;
2311  
2312      foreach ($parts as $key => $part) {
2313          $parts[$key] = substr($haystack, $pos, strlen($part));
2314          $pos += strlen($part);
2315  
2316          $parts[$key] .= '<span class="highlight">'.substr($haystack, $pos, strlen($needle)).'</span>';
2317          $pos += strlen($needle);
2318      }
2319  
2320      return str_replace('<span class="highlight"></span>', '', join('', $parts));
2321  }
2322  
2323  /**
2324   * Converts a language code to hyphen-separated format in accordance to the
2325   * {@link https://datatracker.ietf.org/doc/html/rfc5646#section-2.1 BCP47 syntax}.
2326   *
2327   * For additional information, check out
2328   * {@link https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/lang MDN web docs - lang}.
2329   *
2330   * @param string $langcode The language code to convert.
2331   * @return string
2332   */
2333  function get_html_lang_attribute_value(string $langcode): string {
2334      $langcode = clean_param($langcode, PARAM_LANG);
2335      if ($langcode === '') {
2336          return 'en';
2337      }
2338  
2339      // Grab language ISO code from lang config. If it differs from English, then it's been specified and we can return it.
2340      $langiso = (string) (new lang_string('iso6391', 'core_langconfig', null, $langcode));
2341      if ($langiso !== 'en') {
2342          return $langiso;
2343      }
2344  
2345      // Where we cannot determine the value from lang config, use the first two characters from the lang code.
2346      return substr($langcode, 0, 2);
2347  }
2348  
2349  /**
2350   * Return a string containing 'lang', xml:lang and optionally 'dir' HTML attributes.
2351   *
2352   * Internationalisation, for print_header and backup/restorelib.
2353   *
2354   * @param bool $dir Default false
2355   * @return string Attributes
2356   */
2357  function get_html_lang($dir = false) {
2358      global $CFG;
2359  
2360      $currentlang = current_language();
2361      if (isset($CFG->lang) && $currentlang !== $CFG->lang && !get_string_manager()->translation_exists($currentlang)) {
2362          // Use the default site language when the current language is not available.
2363          $currentlang = $CFG->lang;
2364          // Fix the current language.
2365          fix_current_language($currentlang);
2366      }
2367  
2368      $direction = '';
2369      if ($dir) {
2370          if (right_to_left()) {
2371              $direction = ' dir="rtl"';
2372          } else {
2373              $direction = ' dir="ltr"';
2374          }
2375      }
2376  
2377      // Accessibility: added the 'lang' attribute to $direction, used in theme <html> tag.
2378      $language = get_html_lang_attribute_value($currentlang);
2379      @header('Content-Language: '.$language);
2380      return ($direction.' lang="'.$language.'" xml:lang="'.$language.'"');
2381  }
2382  
2383  
2384  // STANDARD WEB PAGE PARTS.
2385  
2386  /**
2387   * Send the HTTP headers that Moodle requires.
2388   *
2389   * There is a backwards compatibility hack for legacy code
2390   * that needs to add custom IE compatibility directive.
2391   *
2392   * Example:
2393   * <code>
2394   * if (!isset($CFG->additionalhtmlhead)) {
2395   *     $CFG->additionalhtmlhead = '';
2396   * }
2397   * $CFG->additionalhtmlhead .= '<meta http-equiv="X-UA-Compatible" content="IE=8" />';
2398   * header('X-UA-Compatible: IE=8');
2399   * echo $OUTPUT->header();
2400   * </code>
2401   *
2402   * Please note the $CFG->additionalhtmlhead alone might not work,
2403   * you should send the IE compatibility header() too.
2404   *
2405   * @param string $contenttype
2406   * @param bool $cacheable Can this page be cached on back?
2407   * @return void, sends HTTP headers
2408   */
2409  function send_headers($contenttype, $cacheable = true) {
2410      global $CFG;
2411  
2412      @header('Content-Type: ' . $contenttype);
2413      @header('Content-Script-Type: text/javascript');
2414      @header('Content-Style-Type: text/css');
2415  
2416      if (empty($CFG->additionalhtmlhead) or stripos($CFG->additionalhtmlhead, 'X-UA-Compatible') === false) {
2417          @header('X-UA-Compatible: IE=edge');
2418      }
2419  
2420      if ($cacheable) {
2421          // Allow caching on "back" (but not on normal clicks).
2422          @header('Cache-Control: private, pre-check=0, post-check=0, max-age=0, no-transform');
2423          @header('Pragma: no-cache');
2424          @header('Expires: ');
2425      } else {
2426          // Do everything we can to always prevent clients and proxies caching.
2427          @header('Cache-Control: no-store, no-cache, must-revalidate');
2428          @header('Cache-Control: post-check=0, pre-check=0, no-transform', false);
2429          @header('Pragma: no-cache');
2430          @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
2431          @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
2432      }
2433      @header('Accept-Ranges: none');
2434  
2435      // The Moodle app must be allowed to embed content always.
2436      if (empty($CFG->allowframembedding) && !core_useragent::is_moodle_app()) {
2437          @header('X-Frame-Options: sameorigin');
2438      }
2439  
2440      // If referrer policy is set, add a referrer header.
2441      if (!empty($CFG->referrerpolicy) && ($CFG->referrerpolicy !== 'default')) {
2442          @header('Referrer-Policy: ' . $CFG->referrerpolicy);
2443      }
2444  }
2445  
2446  /**
2447   * Return the right arrow with text ('next'), and optionally embedded in a link.
2448   *
2449   * @param string $text HTML/plain text label (set to blank only for breadcrumb separator cases).
2450   * @param string $url An optional link to use in a surrounding HTML anchor.
2451   * @param bool $accesshide True if text should be hidden (for screen readers only).
2452   * @param string $addclass Additional class names for the link, or the arrow character.
2453   * @return string HTML string.
2454   */
2455  function link_arrow_right($text, $url='', $accesshide=false, $addclass='', $addparams = []) {
2456      global $OUTPUT; // TODO: move to output renderer.
2457      $arrowclass = 'arrow ';
2458      if (!$url) {
2459          $arrowclass .= $addclass;
2460      }
2461      $arrow = '<span class="'.$arrowclass.'" aria-hidden="true">'.$OUTPUT->rarrow().'</span>';
2462      $htmltext = '';
2463      if ($text) {
2464          $htmltext = '<span class="arrow_text">'.$text.'</span>&nbsp;';
2465          if ($accesshide) {
2466              $htmltext = get_accesshide($htmltext);
2467          }
2468      }
2469      if ($url) {
2470          $class = 'arrow_link';
2471          if ($addclass) {
2472              $class .= ' '.$addclass;
2473          }
2474  
2475          $linkparams = [
2476              'class' => $class,
2477              'href' => $url,
2478              'title' => preg_replace('/<.*?>/', '', $text),
2479          ];
2480  
2481          $linkparams += $addparams;
2482  
2483          return html_writer::link($url, $htmltext . $arrow, $linkparams);
2484      }
2485      return $htmltext.$arrow;
2486  }
2487  
2488  /**
2489   * Return the left arrow with text ('previous'), and optionally embedded in a link.
2490   *
2491   * @param string $text HTML/plain text label (set to blank only for breadcrumb separator cases).
2492   * @param string $url An optional link to use in a surrounding HTML anchor.
2493   * @param bool $accesshide True if text should be hidden (for screen readers only).
2494   * @param string $addclass Additional class names for the link, or the arrow character.
2495   * @return string HTML string.
2496   */
2497  function link_arrow_left($text, $url='', $accesshide=false, $addclass='', $addparams = []) {
2498      global $OUTPUT; // TODO: move to utput renderer.
2499      $arrowclass = 'arrow ';
2500      if (! $url) {
2501          $arrowclass .= $addclass;
2502      }
2503      $arrow = '<span class="'.$arrowclass.'" aria-hidden="true">'.$OUTPUT->larrow().'</span>';
2504      $htmltext = '';
2505      if ($text) {
2506          $htmltext = '&nbsp;<span class="arrow_text">'.$text.'</span>';
2507          if ($accesshide) {
2508              $htmltext = get_accesshide($htmltext);
2509          }
2510      }
2511      if ($url) {
2512          $class = 'arrow_link';
2513          if ($addclass) {
2514              $class .= ' '.$addclass;
2515          }
2516  
2517          $linkparams = [
2518              'class' => $class,
2519              'href' => $url,
2520              'title' => preg_replace('/<.*?>/', '', $text),
2521          ];
2522  
2523          $linkparams += $addparams;
2524  
2525          return html_writer::link($url, $arrow . $htmltext, $linkparams);
2526      }
2527      return $arrow.$htmltext;
2528  }
2529  
2530  /**
2531   * Return a HTML element with the class "accesshide", for accessibility.
2532   *
2533   * Please use cautiously - where possible, text should be visible!
2534   *
2535   * @param string $text Plain text.
2536   * @param string $elem Lowercase element name, default "span".
2537   * @param string $class Additional classes for the element.
2538   * @param string $attrs Additional attributes string in the form, "name='value' name2='value2'"
2539   * @return string HTML string.
2540   */
2541  function get_accesshide($text, $elem='span', $class='', $attrs='') {
2542      return "<$elem class=\"accesshide $class\" $attrs>$text</$elem>";
2543  }
2544  
2545  /**
2546   * Return the breadcrumb trail navigation separator.
2547   *
2548   * @return string HTML string.
2549   */
2550  function get_separator() {
2551      // Accessibility: the 'hidden' slash is preferred for screen readers.
2552      return ' '.link_arrow_right($text='/', $url='', $accesshide=true, 'sep').' ';
2553  }
2554  
2555  /**
2556   * Print (or return) a collapsible region, that has a caption that can be clicked to expand or collapse the region.
2557   *
2558   * If JavaScript is off, then the region will always be expanded.
2559   *
2560   * @param string $contents the contents of the box.
2561   * @param string $classes class names added to the div that is output.
2562   * @param string $id id added to the div that is output. Must not be blank.
2563   * @param string $caption text displayed at the top. Clicking on this will cause the region to expand or contract.
2564   * @param string $userpref the name of the user preference that stores the user's preferred default state.
2565   *      (May be blank if you do not wish the state to be persisted.
2566   * @param boolean $default Initial collapsed state to use if the user_preference it not set.
2567   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2568   * @return string|void If $return is false, returns nothing, otherwise returns a string of HTML.
2569   */
2570  function print_collapsible_region($contents, $classes, $id, $caption, $userpref = '', $default = false, $return = false) {
2571      $output  = print_collapsible_region_start($classes, $id, $caption, $userpref, $default, true);
2572      $output .= $contents;
2573      $output .= print_collapsible_region_end(true);
2574  
2575      if ($return) {
2576          return $output;
2577      } else {
2578          echo $output;
2579      }
2580  }
2581  
2582  /**
2583   * Print (or return) the start of a collapsible region
2584   *
2585   * The collapsibleregion has a caption that can be clicked to expand or collapse the region. If JavaScript is off, then the region
2586   * will always be expanded.
2587   *
2588   * @param string $classes class names added to the div that is output.
2589   * @param string $id id added to the div that is output. Must not be blank.
2590   * @param string $caption text displayed at the top. Clicking on this will cause the region to expand or contract.
2591   * @param string $userpref the name of the user preference that stores the user's preferred default state.
2592   *      (May be blank if you do not wish the state to be persisted.
2593   * @param boolean $default Initial collapsed state to use if the user_preference it not set.
2594   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2595   * @param string $extracontent the extra content will show next to caption, eg.Help icon.
2596   * @return string|void if $return is false, returns nothing, otherwise returns a string of HTML.
2597   */
2598  function print_collapsible_region_start($classes, $id, $caption, $userpref = '', $default = false, $return = false,
2599          $extracontent = null) {
2600      global $PAGE;
2601  
2602      // Work out the initial state.
2603      if (!empty($userpref) and is_string($userpref)) {
2604          $collapsed = get_user_preferences($userpref, $default);
2605      } else {
2606          $collapsed = $default;
2607          $userpref = false;
2608      }
2609  
2610      if ($collapsed) {
2611          $classes .= ' collapsed';
2612      }
2613  
2614      $output = '';
2615      $output .= '<div id="' . $id . '" class="collapsibleregion ' . $classes . '">';
2616      $output .= '<div id="' . $id . '_sizer">';
2617      $output .= '<div id="' . $id . '_caption" class="collapsibleregioncaption">';
2618      $output .= $caption . ' </div>';
2619      if ($extracontent) {
2620          $output .= html_writer::div($extracontent, 'collapsibleregionextracontent');
2621      }
2622      $output .= '<div id="' . $id . '_inner" class="collapsibleregioninner">';
2623      $PAGE->requires->js_init_call('M.util.init_collapsible_region', array($id, $userpref, get_string('clicktohideshow')));
2624  
2625      if ($return) {
2626          return $output;
2627      } else {
2628          echo $output;
2629      }
2630  }
2631  
2632  /**
2633   * Close a region started with print_collapsible_region_start.
2634   *
2635   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2636   * @return string|void if $return is false, returns nothing, otherwise returns a string of HTML.
2637   */
2638  function print_collapsible_region_end($return = false) {
2639      $output = '</div></div></div>';
2640  
2641      if ($return) {
2642          return $output;
2643      } else {
2644          echo $output;
2645      }
2646  }
2647  
2648  /**
2649   * Print a specified group's avatar.
2650   *
2651   * @param array|stdClass $group A single {@link group} object OR array of groups.
2652   * @param int $courseid The course ID.
2653   * @param boolean $large Default small picture, or large.
2654   * @param boolean $return If false print picture, otherwise return the output as string
2655   * @param boolean $link Enclose image in a link to view specified course?
2656   * @param boolean $includetoken Whether to use a user token when displaying this group image.
2657   *                True indicates to generate a token for current user, and integer value indicates to generate a token for the
2658   *                user whose id is the value indicated.
2659   *                If the group picture is included in an e-mail or some other location where the audience is a specific
2660   *                user who will not be logged in when viewing, then we use a token to authenticate the user.
2661   * @return string|void Depending on the setting of $return
2662   */
2663  function print_group_picture($group, $courseid, $large = false, $return = false, $link = true, $includetoken = false) {
2664      global $CFG;
2665  
2666      if (is_array($group)) {
2667          $output = '';
2668          foreach ($group as $g) {
2669              $output .= print_group_picture($g, $courseid, $large, true, $link, $includetoken);
2670          }
2671          if ($return) {
2672              return $output;
2673          } else {
2674              echo $output;
2675              return;
2676          }
2677      }
2678  
2679      $pictureurl = get_group_picture_url($group, $courseid, $large, $includetoken);
2680  
2681      // If there is no picture, do nothing.
2682      if (!isset($pictureurl)) {
2683          return;
2684      }
2685  
2686      $context = context_course::instance($courseid);
2687  
2688      $groupname = s($group->name);
2689      $pictureimage = html_writer::img($pictureurl, $groupname, ['title' => $groupname]);
2690  
2691      $output = '';
2692      if ($link or has_capability('moodle/site:accessallgroups', $context)) {
2693          $linkurl = new moodle_url('/user/index.php', ['id' => $courseid, 'group' => $group->id]);
2694          $output .= html_writer::link($linkurl, $pictureimage);
2695      } else {
2696          $output .= $pictureimage;
2697      }
2698  
2699      if ($return) {
2700          return $output;
2701      } else {
2702          echo $output;
2703      }
2704  }
2705  
2706  /**
2707   * Return the url to the group picture.
2708   *
2709   * @param  stdClass $group A group object.
2710   * @param  int $courseid The course ID for the group.
2711   * @param  bool $large A large or small group picture? Default is small.
2712   * @param  boolean $includetoken Whether to use a user token when displaying this group image.
2713   *                 True indicates to generate a token for current user, and integer value indicates to generate a token for the
2714   *                 user whose id is the value indicated.
2715   *                 If the group picture is included in an e-mail or some other location where the audience is a specific
2716   *                 user who will not be logged in when viewing, then we use a token to authenticate the user.
2717   * @return moodle_url Returns the url for the group picture.
2718   */
2719  function get_group_picture_url($group, $courseid, $large = false, $includetoken = false) {
2720      global $CFG;
2721  
2722      $context = context_course::instance($courseid);
2723  
2724      // If there is no picture, do nothing.
2725      if (!$group->picture) {
2726          return;
2727      }
2728  
2729      if ($large) {
2730          $file = 'f1';
2731      } else {
2732          $file = 'f2';
2733      }
2734  
2735      $grouppictureurl = moodle_url::make_pluginfile_url(
2736              $context->id, 'group', 'icon', $group->id, '/', $file, false, $includetoken);
2737      $grouppictureurl->param('rev', $group->picture);
2738      return $grouppictureurl;
2739  }
2740  
2741  
2742  /**
2743   * Display a recent activity note
2744   *
2745   * @staticvar string $strftimerecent
2746   * @param int $time A timestamp int.
2747   * @param stdClass $user A user object from the database.
2748   * @param string $text Text for display for the note
2749   * @param string $link The link to wrap around the text
2750   * @param bool $return If set to true the HTML is returned rather than echo'd
2751   * @param string $viewfullnames
2752   * @return string If $retrun was true returns HTML for a recent activity notice.
2753   */
2754  function print_recent_activity_note($time, $user, $text, $link, $return=false, $viewfullnames=null) {
2755      static $strftimerecent = null;
2756      $output = '';
2757  
2758      if (is_null($viewfullnames)) {
2759          $context = context_system::instance();
2760          $viewfullnames = has_capability('moodle/site:viewfullnames', $context);
2761      }
2762  
2763      if (is_null($strftimerecent)) {
2764          $strftimerecent = get_string('strftimerecent');
2765      }
2766  
2767      $output .= '<div class="head">';
2768      $output .= '<div class="date">'.userdate($time, $strftimerecent).'</div>';
2769      $output .= '<div class="name">'.fullname($user, $viewfullnames).'</div>';
2770      $output .= '</div>';
2771      $output .= '<div class="info"><a href="'.$link.'">'.format_string($text, true).'</a></div>';
2772  
2773      if ($return) {
2774          return $output;
2775      } else {
2776          echo $output;
2777      }
2778  }
2779  
2780  /**
2781   * Returns a popup menu with course activity modules
2782   *
2783   * Given a course this function returns a small popup menu with all the course activity modules in it, as a navigation menu
2784   * outputs a simple list structure in XHTML.
2785   * The data is taken from the serialised array stored in the course record.
2786   *
2787   * @param stdClass $course A course object.
2788   * @param array $sections
2789   * @param course_modinfo $modinfo
2790   * @param string $strsection
2791   * @param string $strjumpto
2792   * @param int $width
2793   * @param string $cmid
2794   * @return string The HTML block
2795   */
2796  function navmenulist($course, $sections, $modinfo, $strsection, $strjumpto, $width=50, $cmid=0) {
2797  
2798      global $CFG, $OUTPUT;
2799  
2800      $section = -1;
2801      $menu = array();
2802      $doneheading = false;
2803  
2804      $courseformatoptions = course_get_format($course)->get_format_options();
2805      $coursecontext = context_course::instance($course->id);
2806  
2807      $menu[] = '<ul class="navmenulist"><li class="jumpto section"><span>'.$strjumpto.'</span><ul>';
2808      foreach ($modinfo->cms as $mod) {
2809          if (!$mod->has_view()) {
2810              // Don't show modules which you can't link to!
2811              continue;
2812          }
2813  
2814          // For course formats using 'numsections' do not show extra sections.
2815          if (isset($courseformatoptions['numsections']) && $mod->sectionnum > $courseformatoptions['numsections']) {
2816              break;
2817          }
2818  
2819          if (!$mod->uservisible) { // Do not icnlude empty sections at all.
2820              continue;
2821          }
2822  
2823          if ($mod->sectionnum >= 0 and $section != $mod->sectionnum) {
2824              $thissection = $sections[$mod->sectionnum];
2825  
2826              if ($thissection->visible or
2827                      (isset($courseformatoptions['hiddensections']) and !$courseformatoptions['hiddensections']) or
2828                      has_capability('moodle/course:viewhiddensections', $coursecontext)) {
2829                  $thissection->summary = strip_tags(format_string($thissection->summary, true));
2830                  if (!$doneheading) {
2831                      $menu[] = '</ul></li>';
2832                  }
2833                  if ($course->format == 'weeks' or empty($thissection->summary)) {
2834                      $item = $strsection ." ". $mod->sectionnum;
2835                  } else {
2836                      if (core_text::strlen($thissection->summary) < ($width-3)) {
2837                          $item = $thissection->summary;
2838                      } else {
2839                          $item = core_text::substr($thissection->summary, 0, $width).'...';
2840                      }
2841                  }
2842                  $menu[] = '<li class="section"><span>'.$item.'</span>';
2843                  $menu[] = '<ul>';
2844                  $doneheading = true;
2845  
2846                  $section = $mod->sectionnum;
2847              } else {
2848                  // No activities from this hidden section shown.
2849                  continue;
2850              }
2851          }
2852  
2853          $url = $mod->modname .'/view.php?id='. $mod->id;
2854          $mod->name = strip_tags(format_string($mod->name ,true));
2855          if (core_text::strlen($mod->name) > ($width+5)) {
2856              $mod->name = core_text::substr($mod->name, 0, $width).'...';
2857          }
2858          if (!$mod->visible) {
2859              $mod->name = '('.$mod->name.')';
2860          }
2861          $class = 'activity '.$mod->modname;
2862          $class .= ($cmid == $mod->id) ? ' selected' : '';
2863          $menu[] = '<li class="'.$class.'">'.
2864                    $OUTPUT->image_icon('monologo', '', $mod->modname).
2865                    '<a href="'.$CFG->wwwroot.'/mod/'.$url.'">'.$mod->name.'</a></li>';
2866      }
2867  
2868      if ($doneheading) {
2869          $menu[] = '</ul></li>';
2870      }
2871      $menu[] = '</ul></li></ul>';
2872  
2873      return implode("\n", $menu);
2874  }
2875  
2876  /**
2877   * Prints a grade menu (as part of an existing form) with help showing all possible numerical grades and scales.
2878   *
2879   * @todo Finish documenting this function
2880   * @todo Deprecate: this is only used in a few contrib modules
2881   *
2882   * @param int $courseid The course ID
2883   * @param string $name
2884   * @param string $current
2885   * @param boolean $includenograde Include those with no grades
2886   * @param boolean $return If set to true returns rather than echo's
2887   * @return string|bool Depending on value of $return
2888   */
2889  function print_grade_menu($courseid, $name, $current, $includenograde=true, $return=false) {
2890      global $OUTPUT;
2891  
2892      $output = '';
2893      $strscale = get_string('scale');
2894      $strscales = get_string('scales');
2895  
2896      $scales = get_scales_menu($courseid);
2897      foreach ($scales as $i => $scalename) {
2898          $grades[-$i] = $strscale .': '. $scalename;
2899      }
2900      if ($includenograde) {
2901          $grades[0] = get_string('nograde');
2902      }
2903      for ($i=100; $i>=1; $i--) {
2904          $grades[$i] = $i;
2905      }
2906      $output .= html_writer::select($grades, $name, $current, false);
2907  
2908      $linkobject = '<span class="helplink">' . $OUTPUT->pix_icon('help', $strscales) . '</span>';
2909      $link = new moodle_url('/course/scales.php', array('id' => $courseid, 'list' => 1));
2910      $action = new popup_action('click', $link, 'ratingscales', array('height' => 400, 'width' => 500));
2911      $output .= $OUTPUT->action_link($link, $linkobject, $action, array('title' => $strscales));
2912  
2913      if ($return) {
2914          return $output;
2915      } else {
2916          echo $output;
2917      }
2918  }
2919  
2920  /**
2921   * Print an error to STDOUT and exit with a non-zero code. For commandline scripts.
2922   *
2923   * Default errorcode is 1.
2924   *
2925   * Very useful for perl-like error-handling:
2926   * do_somethting() or mdie("Something went wrong");
2927   *
2928   * @param string  $msg       Error message
2929   * @param integer $errorcode Error code to emit
2930   */
2931  function mdie($msg='', $errorcode=1) {
2932      trigger_error($msg);
2933      exit($errorcode);
2934  }
2935  
2936  /**
2937   * Print a message and exit.
2938   *
2939   * @param string $message The message to print in the notice
2940   * @param moodle_url|string $link The link to use for the continue button
2941   * @param object $course A course object. Unused.
2942   * @return void This function simply exits
2943   */
2944  function notice ($message, $link='', $course=null) {
2945      global $PAGE, $OUTPUT;
2946  
2947      $message = clean_text($message);   // In case nasties are in here.
2948  
2949      if (CLI_SCRIPT) {
2950          echo("!!$message!!\n");
2951          exit(1); // No success.
2952      }
2953  
2954      if (!$PAGE->headerprinted) {
2955          // Header not yet printed.
2956          $PAGE->set_title(get_string('notice'));
2957          echo $OUTPUT->header();
2958      } else {
2959          echo $OUTPUT->container_end_all(false);
2960      }
2961  
2962      echo $OUTPUT->box($message, 'generalbox', 'notice');
2963      echo $OUTPUT->continue_button($link);
2964  
2965      echo $OUTPUT->footer();
2966      exit(1); // General error code.
2967  }
2968  
2969  /**
2970   * Redirects the user to another page, after printing a notice.
2971   *
2972   * This function calls the OUTPUT redirect method, echo's the output and then dies to ensure nothing else happens.
2973   *
2974   * <strong>Good practice:</strong> You should call this method before starting page
2975   * output by using any of the OUTPUT methods.
2976   *
2977   * @param moodle_url|string $url A moodle_url to redirect to. Strings are not to be trusted!
2978   * @param string $message The message to display to the user
2979   * @param int $delay The delay before redirecting
2980   * @param string $messagetype The type of notification to show the message in. See constants on \core\output\notification.
2981   * @throws moodle_exception
2982   */
2983  function redirect($url, $message='', $delay=null, $messagetype = \core\output\notification::NOTIFY_INFO) {
2984      global $OUTPUT, $PAGE, $CFG;
2985  
2986      if (CLI_SCRIPT or AJAX_SCRIPT) {
2987          // This is wrong - developers should not use redirect in these scripts but it should not be very likely.
2988          throw new moodle_exception('redirecterrordetected', 'error');
2989      }
2990  
2991      if ($delay === null) {
2992          $delay = -1;
2993      }
2994  
2995      // Prevent debug errors - make sure context is properly initialised.
2996      if ($PAGE) {
2997          $PAGE->set_context(null);
2998          $PAGE->set_pagelayout('redirect');  // No header and footer needed.
2999          $PAGE->set_title(get_string('pageshouldredirect', 'moodle'));
3000      }
3001  
3002      if ($url instanceof moodle_url) {
3003          $url = $url->out(false);
3004      }
3005  
3006      $debugdisableredirect = false;
3007      do {
3008          if (defined('DEBUGGING_PRINTED')) {
3009              // Some debugging already printed, no need to look more.
3010              $debugdisableredirect = true;
3011              break;
3012          }
3013  
3014          if (core_useragent::is_msword()) {
3015              // Clicking a URL from MS Word sends a request to the server without cookies. If that
3016              // causes a redirect Word will open a browser pointing the new URL. If not, the URL that
3017              // was clicked is opened. Because the request from Word is without cookies, it almost
3018              // always results in a redirect to the login page, even if the user is logged in in their
3019              // browser. This is not what we want, so prevent the redirect for requests from Word.
3020              $debugdisableredirect = true;
3021              break;
3022          }
3023  
3024          if (empty($CFG->debugdisplay) or empty($CFG->debug)) {
3025              // No errors should be displayed.
3026              break;
3027          }
3028  
3029          if (!function_exists('error_get_last') or !$lasterror = error_get_last()) {
3030              break;
3031          }
3032  
3033          if (!($lasterror['type'] & $CFG->debug)) {
3034              // Last error not interesting.
3035              break;
3036          }
3037  
3038          // Watch out here, @hidden() errors are returned from error_get_last() too.
3039          if (headers_sent()) {
3040              // We already started printing something - that means errors likely printed.
3041              $debugdisableredirect = true;
3042              break;
3043          }
3044  
3045          if (ob_get_level() and ob_get_contents()) {
3046              // There is something waiting to be printed, hopefully it is the errors,
3047              // but it might be some error hidden by @ too - such as the timezone mess from setup.php.
3048              $debugdisableredirect = true;
3049              break;
3050          }
3051      } while (false);
3052  
3053      // Technically, HTTP/1.1 requires Location: header to contain the absolute path.
3054      // (In practice browsers accept relative paths - but still, might as well do it properly.)
3055      // This code turns relative into absolute.
3056      if (!preg_match('|^[a-z]+:|i', $url)) {
3057          // Get host name http://www.wherever.com.
3058          $hostpart = preg_replace('|^(.*?[^:/])/.*$|', '$1', $CFG->wwwroot);
3059          if (preg_match('|^/|', $url)) {
3060              // URLs beginning with / are relative to web server root so we just add them in.
3061              $url = $hostpart.$url;
3062          } else {
3063              // URLs not beginning with / are relative to path of current script, so add that on.
3064              $url = $hostpart.preg_replace('|\?.*$|', '', me()).'/../'.$url;
3065          }
3066          // Replace all ..s.
3067          while (true) {
3068              $newurl = preg_replace('|/(?!\.\.)[^/]*/\.\./|', '/', $url);
3069              if ($newurl == $url) {
3070                  break;
3071              }
3072              $url = $newurl;
3073          }
3074      }
3075  
3076      // Sanitise url - we can not rely on moodle_url or our URL cleaning
3077      // because they do not support all valid external URLs.
3078      $url = preg_replace('/[\x00-\x1F\x7F]/', '', $url);
3079      $url = str_replace('"', '%22', $url);
3080      $encodedurl = preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&amp;", $url);
3081      $encodedurl = preg_replace('/^.*href="([^"]*)".*$/', "\\1", clean_text('<a href="'.$encodedurl.'" />', FORMAT_HTML));
3082      $url = str_replace('&amp;', '&', $encodedurl);
3083  
3084      if (!empty($message)) {
3085          if (!$debugdisableredirect && !headers_sent()) {
3086              // A message has been provided, and the headers have not yet been sent.
3087              // Display the message as a notification on the subsequent page.
3088              \core\notification::add($message, $messagetype);
3089              $message = null;
3090              $delay = 0;
3091          } else {
3092              if ($delay === -1 || !is_numeric($delay)) {
3093                  $delay = 3;
3094              }
3095              $message = clean_text($message);
3096          }
3097      } else {
3098          $message = get_string('pageshouldredirect');
3099          $delay = 0;
3100      }
3101  
3102      // Make sure the session is closed properly, this prevents problems in IIS
3103      // and also some potential PHP shutdown issues.
3104      \core\session\manager::write_close();
3105  
3106      if ($delay == 0 && !$debugdisableredirect && !headers_sent()) {
3107  
3108          // This helps when debugging redirect issues like loops and it is not clear
3109          // which layer in the stack sent the redirect header. If debugging is on
3110          // then the file and line is also shown.
3111          $redirectby = 'Moodle';
3112          if (debugging('', DEBUG_DEVELOPER)) {
3113              $origin = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 1)[0];
3114              $redirectby .= ' /' . str_replace($CFG->dirroot . '/', '', $origin['file']) . ':' . $origin['line'];
3115          }
3116          @header("X-Redirect-By: $redirectby");
3117  
3118          // 302 might not work for POST requests, 303 is ignored by obsolete clients.
3119          @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
3120          @header('Location: '.$url);
3121          echo bootstrap_renderer::plain_redirect_message($encodedurl);
3122          exit;
3123      }
3124  
3125      // Include a redirect message, even with a HTTP redirect, because that is recommended practice.
3126      if ($PAGE) {
3127          $CFG->docroot = false; // To prevent the link to moodle docs from being displayed on redirect page.
3128          echo $OUTPUT->redirect_message($encodedurl, $message, $delay, $debugdisableredirect, $messagetype);
3129          exit;
3130      } else {
3131          echo bootstrap_renderer::early_redirect_message($encodedurl, $message, $delay);
3132          exit;
3133      }
3134  }
3135  
3136  /**
3137   * Given an email address, this function will return an obfuscated version of it.
3138   *
3139   * @param string $email The email address to obfuscate
3140   * @return string The obfuscated email address
3141   */
3142  function obfuscate_email($email) {
3143      $i = 0;
3144      $length = strlen($email);
3145      $obfuscated = '';
3146      while ($i < $length) {
3147          if (rand(0, 2) && $email[$i]!='@') { // MDL-20619 some browsers have problems unobfuscating @.
3148              $obfuscated.='%'.dechex(ord($email[$i]));
3149          } else {
3150              $obfuscated.=$email[$i];
3151          }
3152          $i++;
3153      }
3154      return $obfuscated;
3155  }
3156  
3157  /**
3158   * This function takes some text and replaces about half of the characters
3159   * with HTML entity equivalents.   Return string is obviously longer.
3160   *
3161   * @param string $plaintext The text to be obfuscated
3162   * @return string The obfuscated text
3163   */
3164  function obfuscate_text($plaintext) {
3165      $i=0;
3166      $length = core_text::strlen($plaintext);
3167      $obfuscated='';
3168      $prevobfuscated = false;
3169      while ($i < $length) {
3170          $char = core_text::substr($plaintext, $i, 1);
3171          $ord = core_text::utf8ord($char);
3172          $numerical = ($ord >= ord('0')) && ($ord <= ord('9'));
3173          if ($prevobfuscated and $numerical ) {
3174              $obfuscated.='&#'.$ord.';';
3175          } else if (rand(0, 2)) {
3176              $obfuscated.='&#'.$ord.';';
3177              $prevobfuscated = true;
3178          } else {
3179              $obfuscated.=$char;
3180              $prevobfuscated = false;
3181          }
3182          $i++;
3183      }
3184      return $obfuscated;
3185  }
3186  
3187  /**
3188   * This function uses the {@link obfuscate_email()} and {@link obfuscate_text()}
3189   * to generate a fully obfuscated email link, ready to use.
3190   *
3191   * @param string $email The email address to display
3192   * @param string $label The text to displayed as hyperlink to $email
3193   * @param boolean $dimmed If true then use css class 'dimmed' for hyperlink
3194   * @param string $subject The subject of the email in the mailto link
3195   * @param string $body The content of the email in the mailto link
3196   * @return string The obfuscated mailto link
3197   */
3198  function obfuscate_mailto($email, $label='', $dimmed=false, $subject = '', $body = '') {
3199  
3200      if (empty($label)) {
3201          $label = $email;
3202      }
3203  
3204      $label = obfuscate_text($label);
3205      $email = obfuscate_email($email);
3206      $mailto = obfuscate_text('mailto');
3207      $url = new moodle_url("mailto:$email");
3208      $attrs = array();
3209  
3210      if (!empty($subject)) {
3211          $url->param('subject', format_string($subject));
3212      }
3213      if (!empty($body)) {
3214          $url->param('body', format_string($body));
3215      }
3216  
3217      // Use the obfuscated mailto.
3218      $url = preg_replace('/^mailto/', $mailto, $url->out());
3219  
3220      if ($dimmed) {
3221          $attrs['title'] = get_string('emaildisable');
3222          $attrs['class'] = 'dimmed';
3223      }
3224  
3225      return html_writer::link($url, $label, $attrs);
3226  }
3227  
3228  /**
3229   * This function is used to rebuild the <nolink> tag because some formats (PLAIN and WIKI)
3230   * will transform it to html entities
3231   *
3232   * @param string $text Text to search for nolink tag in
3233   * @return string
3234   */
3235  function rebuildnolinktag($text) {
3236  
3237      $text = preg_replace('/&lt;(\/*nolink)&gt;/i', '<$1>', $text);
3238  
3239      return $text;
3240  }
3241  
3242  /**
3243   * Prints a maintenance message from $CFG->maintenance_message or default if empty.
3244   */
3245  function print_maintenance_message() {
3246      global $CFG, $SITE, $PAGE, $OUTPUT;
3247  
3248      header($_SERVER['SERVER_PROTOCOL'] . ' 503 Moodle under maintenance');
3249      header('Status: 503 Moodle under maintenance');
3250      header('Retry-After: 300');
3251  
3252      $PAGE->set_pagetype('maintenance-message');
3253      $PAGE->set_pagelayout('maintenance');
3254      $PAGE->set_heading($SITE->fullname);
3255      echo $OUTPUT->header();
3256      echo $OUTPUT->heading(get_string('sitemaintenance', 'admin'));
3257      if (isset($CFG->maintenance_message) and !html_is_blank($CFG->maintenance_message)) {
3258          echo $OUTPUT->box_start('maintenance_message generalbox boxwidthwide boxaligncenter');
3259          echo $CFG->maintenance_message;
3260          echo $OUTPUT->box_end();
3261      }
3262      echo $OUTPUT->footer();
3263      die;
3264  }
3265  
3266  /**
3267   * Returns a string containing a nested list, suitable for formatting into tabs with CSS.
3268   *
3269   * It is not recommended to use this function in Moodle 2.5 but it is left for backward
3270   * compartibility.
3271   *
3272   * Example how to print a single line tabs:
3273   * $rows = array(
3274   *    new tabobject(...),
3275   *    new tabobject(...)
3276   * );
3277   * echo $OUTPUT->tabtree($rows, $selectedid);
3278   *
3279   * Multiple row tabs may not look good on some devices but if you want to use them
3280   * you can specify ->subtree for the active tabobject.
3281   *
3282   * @param array $tabrows An array of rows where each row is an array of tab objects
3283   * @param string $selected  The id of the selected tab (whatever row it's on)
3284   * @param array  $inactive  An array of ids of inactive tabs that are not selectable.
3285   * @param array  $activated An array of ids of other tabs that are currently activated
3286   * @param bool $return If true output is returned rather then echo'd
3287   * @return string HTML output if $return was set to true.
3288   */
3289  function print_tabs($tabrows, $selected = null, $inactive = null, $activated = null, $return = false) {
3290      global $OUTPUT;
3291  
3292      $tabrows = array_reverse($tabrows);
3293      $subtree = array();
3294      foreach ($tabrows as $row) {
3295          $tree = array();
3296  
3297          foreach ($row as $tab) {
3298              $tab->inactive = is_array($inactive) && in_array((string)$tab->id, $inactive);
3299              $tab->activated = is_array($activated) && in_array((string)$tab->id, $activated);
3300              $tab->selected = (string)$tab->id == $selected;
3301  
3302              if ($tab->activated || $tab->selected) {
3303                  $tab->subtree = $subtree;
3304              }
3305              $tree[] = $tab;
3306          }
3307          $subtree = $tree;
3308      }
3309      $output = $OUTPUT->tabtree($subtree);
3310      if ($return) {
3311          return $output;
3312      } else {
3313          print $output;
3314          return !empty($output);
3315      }
3316  }
3317  
3318  /**
3319   * Alter debugging level for the current request,
3320   * the change is not saved in database.
3321   *
3322   * @param int $level one of the DEBUG_* constants
3323   * @param bool $debugdisplay
3324   */
3325  function set_debugging($level, $debugdisplay = null) {
3326      global $CFG;
3327  
3328      $CFG->debug = (int)$level;
3329      $CFG->debugdeveloper = (($CFG->debug & DEBUG_DEVELOPER) === DEBUG_DEVELOPER);
3330  
3331      if ($debugdisplay !== null) {
3332          $CFG->debugdisplay = (bool)$debugdisplay;
3333      }
3334  }
3335  
3336  /**
3337   * Standard Debugging Function
3338   *
3339   * Returns true if the current site debugging settings are equal or above specified level.
3340   * If passed a parameter it will emit a debugging notice similar to trigger_error(). The
3341   * routing of notices is controlled by $CFG->debugdisplay
3342   * eg use like this:
3343   *
3344   * 1)  debugging('a normal debug notice');
3345   * 2)  debugging('something really picky', DEBUG_ALL);
3346   * 3)  debugging('annoying debug message only for developers', DEBUG_DEVELOPER);
3347   * 4)  if (debugging()) { perform extra debugging operations (do not use print or echo) }
3348   *
3349   * In code blocks controlled by debugging() (such as example 4)
3350   * any output should be routed via debugging() itself, or the lower-level
3351   * trigger_error() or error_log(). Using echo or print will break XHTML
3352   * JS and HTTP headers.
3353   *
3354   * It is also possible to define NO_DEBUG_DISPLAY which redirects the message to error_log.
3355   *
3356   * @param string $message a message to print
3357   * @param int $level the level at which this debugging statement should show
3358   * @param array $backtrace use different backtrace
3359   * @return bool
3360   */
3361  function debugging($message = '', $level = DEBUG_NORMAL, $backtrace = null) {
3362      global $CFG, $USER;
3363  
3364      $forcedebug = false;
3365      if (!empty($CFG->debugusers) && $USER) {
3366          $debugusers = explode(',', $CFG->debugusers);
3367          $forcedebug = in_array($USER->id, $debugusers);
3368      }
3369  
3370      if (!$forcedebug and (empty($CFG->debug) || ($CFG->debug != -1 and $CFG->debug < $level))) {
3371          return false;
3372      }
3373  
3374      if (!isset($CFG->debugdisplay)) {
3375          $CFG->debugdisplay = ini_get_bool('display_errors');
3376      }
3377  
3378      if ($message) {
3379          if (!$backtrace) {
3380              $backtrace = debug_backtrace();
3381          }
3382          $from = format_backtrace($backtrace, CLI_SCRIPT || NO_DEBUG_DISPLAY);
3383          if (PHPUNIT_TEST) {
3384              if (phpunit_util::debugging_triggered($message, $level, $from)) {
3385                  // We are inside test, the debug message was logged.
3386                  return true;
3387              }
3388          }
3389  
3390          if (NO_DEBUG_DISPLAY) {
3391              // Script does not want any errors or debugging in output,
3392              // we send the info to error log instead.
3393              error_log('Debugging: ' . $message . ' in '. PHP_EOL . $from);
3394  
3395          } else if ($forcedebug or $CFG->debugdisplay) {
3396              if (!defined('DEBUGGING_PRINTED')) {
3397                  define('DEBUGGING_PRINTED', 1); // Indicates we have printed something.
3398              }
3399              if (CLI_SCRIPT) {
3400                  echo "++ $message ++\n$from";
3401              } else {
3402                  echo '<div class="notifytiny debuggingmessage" data-rel="debugging">' , $message , $from , '</div>';
3403              }
3404  
3405          } else {
3406              trigger_error($message . $from, E_USER_NOTICE);
3407          }
3408      }
3409      return true;
3410  }
3411  
3412  /**
3413   * Outputs a HTML comment to the browser.
3414   *
3415   * This is used for those hard-to-debug pages that use bits from many different files in very confusing ways (e.g. blocks).
3416   *
3417   * <code>print_location_comment(__FILE__, __LINE__);</code>
3418   *
3419   * @param string $file
3420   * @param integer $line
3421   * @param boolean $return Whether to return or print the comment
3422   * @return string|void Void unless true given as third parameter
3423   */
3424  function print_location_comment($file, $line, $return = false) {
3425      if ($return) {
3426          return "<!-- $file at line $line -->\n";
3427      } else {
3428          echo "<!-- $file at line $line -->\n";
3429      }
3430  }
3431  
3432  
3433  /**
3434   * Returns true if the user is using a right-to-left language.
3435   *
3436   * @return boolean true if the current language is right-to-left (Hebrew, Arabic etc)
3437   */
3438  function right_to_left() {
3439      return (get_string('thisdirection', 'langconfig') === 'rtl');
3440  }
3441  
3442  
3443  /**
3444   * Returns swapped left<=> right if in RTL environment.
3445   *
3446   * Part of RTL Moodles support.
3447   *
3448   * @param string $align align to check
3449   * @return string
3450   */
3451  function fix_align_rtl($align) {
3452      if (!right_to_left()) {
3453          return $align;
3454      }
3455      if ($align == 'left') {
3456          return 'right';
3457      }
3458      if ($align == 'right') {
3459          return 'left';
3460      }
3461      return $align;
3462  }
3463  
3464  
3465  /**
3466   * Returns true if the page is displayed in a popup window.
3467   *
3468   * Gets the information from the URL parameter inpopup.
3469   *
3470   * @todo Use a central function to create the popup calls all over Moodle and
3471   * In the moment only works with resources and probably questions.
3472   *
3473   * @return boolean
3474   */
3475  function is_in_popup() {
3476      $inpopup = optional_param('inpopup', '', PARAM_BOOL);
3477  
3478      return ($inpopup);
3479  }
3480  
3481  /**
3482   * Progress trace class.
3483   *
3484   * Use this class from long operations where you want to output occasional information about
3485   * what is going on, but don't know if, or in what format, the output should be.
3486   *
3487   * @copyright 2009 Tim Hunt
3488   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3489   * @package core
3490   */
3491  abstract class progress_trace {
3492      /**
3493       * Output an progress message in whatever format.
3494       *
3495       * @param string $message the message to output.
3496       * @param integer $depth indent depth for this message.
3497       */
3498      abstract public function output($message, $depth = 0);
3499  
3500      /**
3501       * Called when the processing is finished.
3502       */
3503      public function finished() {
3504      }
3505  }
3506  
3507  /**
3508   * This subclass of progress_trace does not ouput anything.
3509   *
3510   * @copyright 2009 Tim Hunt
3511   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3512   * @package core
3513   */
3514  class null_progress_trace extends progress_trace {
3515      /**
3516       * Does Nothing
3517       *
3518       * @param string $message
3519       * @param int $depth
3520       * @return void Does Nothing
3521       */
3522      public function output($message, $depth = 0) {
3523      }
3524  }
3525  
3526  /**
3527   * This subclass of progress_trace outputs to plain text.
3528   *
3529   * @copyright 2009 Tim Hunt
3530   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3531   * @package core
3532   */
3533  class text_progress_trace extends progress_trace {
3534      /**
3535       * Output the trace message.
3536       *
3537       * @param string $message
3538       * @param int $depth
3539       * @return void Output is echo'd
3540       */
3541      public function output($message, $depth = 0) {
3542          mtrace(str_repeat('  ', $depth) . $message);
3543      }
3544  }
3545  
3546  /**
3547   * This subclass of progress_trace outputs as HTML.
3548   *
3549   * @copyright 2009 Tim Hunt
3550   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3551   * @package core
3552   */
3553  class html_progress_trace extends progress_trace {
3554      /**
3555       * Output the trace message.
3556       *
3557       * @param string $message
3558       * @param int $depth
3559       * @return void Output is echo'd
3560       */
3561      public function output($message, $depth = 0) {
3562          echo '<p>', str_repeat('&#160;&#160;', $depth), htmlspecialchars($message, ENT_COMPAT), "</p>\n";
3563          flush();
3564      }
3565  }
3566  
3567  /**
3568   * HTML List Progress Tree
3569   *
3570   * @copyright 2009 Tim Hunt
3571   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3572   * @package core
3573   */
3574  class html_list_progress_trace extends progress_trace {
3575      /** @var int */
3576      protected $currentdepth = -1;
3577  
3578      /**
3579       * Echo out the list
3580       *
3581       * @param string $message The message to display
3582       * @param int $depth
3583       * @return void Output is echoed
3584       */
3585      public function output($message, $depth = 0) {
3586          $samedepth = true;
3587          while ($this->currentdepth > $depth) {
3588              echo "</li>\n</ul>\n";
3589              $this->currentdepth -= 1;
3590              if ($this->currentdepth == $depth) {
3591                  echo '<li>';
3592              }
3593              $samedepth = false;
3594          }
3595          while ($this->currentdepth < $depth) {
3596              echo "<ul>\n<li>";
3597              $this->currentdepth += 1;
3598              $samedepth = false;
3599          }
3600          if ($samedepth) {
3601              echo "</li>\n<li>";
3602          }
3603          echo htmlspecialchars($message, ENT_COMPAT);
3604          flush();
3605      }
3606  
3607      /**
3608       * Called when the processing is finished.
3609       */
3610      public function finished() {
3611          while ($this->currentdepth >= 0) {
3612              echo "</li>\n</ul>\n";
3613              $this->currentdepth -= 1;
3614          }
3615      }
3616  }
3617  
3618  /**
3619   * This subclass of progress_trace outputs to error log.
3620   *
3621   * @copyright Petr Skoda {@link http://skodak.org}
3622   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3623   * @package core
3624   */
3625  class error_log_progress_trace extends progress_trace {
3626      /** @var string log prefix */
3627      protected $prefix;
3628  
3629      /**
3630       * Constructor.
3631       * @param string $prefix optional log prefix
3632       */
3633      public function __construct($prefix = '') {
3634          $this->prefix = $prefix;
3635      }
3636  
3637      /**
3638       * Output the trace message.
3639       *
3640       * @param string $message
3641       * @param int $depth
3642       * @return void Output is sent to error log.
3643       */
3644      public function output($message, $depth = 0) {
3645          error_log($this->prefix . str_repeat('  ', $depth) . $message);
3646      }
3647  }
3648  
3649  /**
3650   * Special type of trace that can be used for catching of output of other traces.
3651   *
3652   * @copyright Petr Skoda {@link http://skodak.org}
3653   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3654   * @package core
3655   */
3656  class progress_trace_buffer extends progress_trace {
3657      /** @var progress_trace */
3658      protected $trace;
3659      /** @var bool do we pass output out */
3660      protected $passthrough;
3661      /** @var string output buffer */
3662      protected $buffer;
3663  
3664      /**
3665       * Constructor.
3666       *
3667       * @param progress_trace $trace
3668       * @param bool $passthrough true means output and buffer, false means just buffer and no output
3669       */
3670      public function __construct(progress_trace $trace, $passthrough = true) {
3671          $this->trace       = $trace;
3672          $this->passthrough = $passthrough;
3673          $this->buffer      = '';
3674      }
3675  
3676      /**
3677       * Output the trace message.
3678       *
3679       * @param string $message the message to output.
3680       * @param int $depth indent depth for this message.
3681       * @return void output stored in buffer
3682       */
3683      public function output($message, $depth = 0) {
3684          ob_start();
3685          $this->trace->output($message, $depth);
3686          $this->buffer .= ob_get_contents();
3687          if ($this->passthrough) {
3688              ob_end_flush();
3689          } else {
3690              ob_end_clean();
3691          }
3692      }
3693  
3694      /**
3695       * Called when the processing is finished.
3696       */
3697      public function finished() {
3698          ob_start();
3699          $this->trace->finished();
3700          $this->buffer .= ob_get_contents();
3701          if ($this->passthrough) {
3702              ob_end_flush();
3703          } else {
3704              ob_end_clean();
3705          }
3706      }
3707  
3708      /**
3709       * Reset internal text buffer.
3710       */
3711      public function reset_buffer() {
3712          $this->buffer = '';
3713      }
3714  
3715      /**
3716       * Return internal text buffer.
3717       * @return string buffered plain text
3718       */
3719      public function get_buffer() {
3720          return $this->buffer;
3721      }
3722  }
3723  
3724  /**
3725   * Special type of trace that can be used for redirecting to multiple other traces.
3726   *
3727   * @copyright Petr Skoda {@link http://skodak.org}
3728   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3729   * @package core
3730   */
3731  class combined_progress_trace extends progress_trace {
3732  
3733      /**
3734       * An array of traces.
3735       * @var array
3736       */
3737      protected $traces;
3738  
3739      /**
3740       * Constructs a new instance.
3741       *
3742       * @param array $traces multiple traces
3743       */
3744      public function __construct(array $traces) {
3745          $this->traces = $traces;
3746      }
3747  
3748      /**
3749       * Output an progress message in whatever format.
3750       *
3751       * @param string $message the message to output.
3752       * @param integer $depth indent depth for this message.
3753       */
3754      public function output($message, $depth = 0) {
3755          foreach ($this->traces as $trace) {
3756              $trace->output($message, $depth);
3757          }
3758      }
3759  
3760      /**
3761       * Called when the processing is finished.
3762       */
3763      public function finished() {
3764          foreach ($this->traces as $trace) {
3765              $trace->finished();
3766          }
3767      }
3768  }
3769  
3770  /**
3771   * Returns a localized sentence in the current language summarizing the current password policy
3772   *
3773   * @todo this should be handled by a function/method in the language pack library once we have a support for it
3774   * @uses $CFG
3775   * @return string
3776   */
3777  function print_password_policy() {
3778      global $CFG;
3779  
3780      $message = '';
3781      if (!empty($CFG->passwordpolicy)) {
3782          $messages = array();
3783          if (!empty($CFG->minpasswordlength)) {
3784              $messages[] = get_string('informminpasswordlength', 'auth', $CFG->minpasswordlength);
3785          }
3786          if (!empty($CFG->minpassworddigits)) {
3787              $messages[] = get_string('informminpassworddigits', 'auth', $CFG->minpassworddigits);
3788          }
3789          if (!empty($CFG->minpasswordlower)) {
3790              $messages[] = get_string('informminpasswordlower', 'auth', $CFG->minpasswordlower);
3791          }
3792          if (!empty($CFG->minpasswordupper)) {
3793              $messages[] = get_string('informminpasswordupper', 'auth', $CFG->minpasswordupper);
3794          }
3795          if (!empty($CFG->minpasswordnonalphanum)) {
3796              $messages[] = get_string('informminpasswordnonalphanum', 'auth', $CFG->minpasswordnonalphanum);
3797          }
3798  
3799          // Fire any additional password policy functions from plugins.
3800          // Callbacks must return an array of message strings.
3801          $pluginsfunction = get_plugins_with_function('print_password_policy');
3802          foreach ($pluginsfunction as $plugintype => $plugins) {
3803              foreach ($plugins as $pluginfunction) {
3804                  $messages = array_merge($messages, $pluginfunction());
3805              }
3806          }
3807  
3808          $messages = join(', ', $messages); // This is ugly but we do not have anything better yet...
3809          // Check if messages is empty before outputting any text.
3810          if ($messages != '') {
3811              $message = get_string('informpasswordpolicy', 'auth', $messages);
3812          }
3813      }
3814      return $message;
3815  }
3816  
3817  /**
3818   * Get the value of a help string fully prepared for display in the current language.
3819   *
3820   * @param string $identifier The identifier of the string to search for.
3821   * @param string $component The module the string is associated with.
3822   * @param boolean $ajax Whether this help is called from an AJAX script.
3823   *                This is used to influence text formatting and determines
3824   *                which format to output the doclink in.
3825   * @param string|object|array $a An object, string or number that can be used
3826   *      within translation strings
3827   * @return stdClass An object containing:
3828   * - heading: Any heading that there may be for this help string.
3829   * - text: The wiki-formatted help string.
3830   * - doclink: An object containing a link, the linktext, and any additional
3831   *            CSS classes to apply to that link. Only present if $ajax = false.
3832   * - completedoclink: A text representation of the doclink. Only present if $ajax = true.
3833   */
3834  function get_formatted_help_string($identifier, $component, $ajax = false, $a = null) {
3835      global $CFG, $OUTPUT;
3836      $sm = get_string_manager();
3837  
3838      // Do not rebuild caches here!
3839      // Devs need to learn to purge all caches after any change or disable $CFG->langstringcache.
3840  
3841      $data = new stdClass();
3842  
3843      if ($sm->string_exists($identifier, $component)) {
3844          $data->heading = format_string(get_string($identifier, $component));
3845      } else {
3846          // Gracefully fall back to an empty string.
3847          $data->heading = '';
3848      }
3849  
3850      if ($sm->string_exists($identifier . '_help', $component)) {
3851          $options = new stdClass();
3852          $options->trusted = false;
3853          $options->noclean = false;
3854          $options->smiley = false;
3855          $options->filter = false;
3856          $options->para = true;
3857          $options->newlines = false;
3858          $options->overflowdiv = !$ajax;
3859  
3860          // Should be simple wiki only MDL-21695.
3861          $data->text = format_text(get_string($identifier.'_help', $component, $a), FORMAT_MARKDOWN, $options);
3862  
3863          $helplink = $identifier . '_link';
3864          if ($sm->string_exists($helplink, $component)) {  // Link to further info in Moodle docs.
3865              $link = get_string($helplink, $component);
3866              $linktext = get_string('morehelp');
3867  
3868              $data->doclink = new stdClass();
3869              $url = new moodle_url(get_docs_url($link));
3870              if ($ajax) {
3871                  $data->doclink->link = $url->out();
3872                  $data->doclink->linktext = $linktext;
3873                  $data->doclink->class = ($CFG->doctonewwindow) ? 'helplinkpopup' : '';
3874              } else {
3875                  $data->completedoclink = html_writer::tag('div', $OUTPUT->doc_link($link, $linktext),
3876                      array('class' => 'helpdoclink'));
3877              }
3878          }
3879      } else {
3880          $data->text = html_writer::tag('p',
3881              html_writer::tag('strong', 'TODO') . ": missing help string [{$identifier}_help, {$component}]");
3882      }
3883      return $data;
3884  }