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