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   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      // When we move to PHP 5.4 as a minimum version, change ENT_QUOTES on the
 100      // next line to ENT_QUOTES | ENT_HTML5 | ENT_SUBSTITUTE, and remove the
 101      // 'UTF-8' argument. Both bring a speed-increase.
 102      return preg_replace('/&amp;#(\d+|x[0-9a-f]+);/i', '&#$1;', htmlspecialchars($var, ENT_QUOTES, 'UTF-8'));
 103  }
 104  
 105  /**
 106   * Add quotes to HTML characters.
 107   *
 108   * Prints $var with HTML characters (like "<", ">", etc.) properly quoted.
 109   * This function simply calls & displays {@link s()}.
 110   * @see s()
 111   *
 112   * @param string $var the string potentially containing HTML characters
 113   * @return string
 114   */
 115  function p($var) {
 116      echo s($var);
 117  }
 118  
 119  /**
 120   * Does proper javascript quoting.
 121   *
 122   * Do not use addslashes anymore, because it does not work when magic_quotes_sybase is enabled.
 123   *
 124   * @param mixed $var String, Array, or Object to add slashes to
 125   * @return mixed quoted result
 126   */
 127  function addslashes_js($var) {
 128      if (is_string($var)) {
 129          $var = str_replace('\\', '\\\\', $var);
 130          $var = str_replace(array('\'', '"', "\n", "\r", "\0"), array('\\\'', '\\"', '\\n', '\\r', '\\0'), $var);
 131          $var = str_replace('</', '<\/', $var);   // XHTML compliance.
 132      } else if (is_array($var)) {
 133          $var = array_map('addslashes_js', $var);
 134      } else if (is_object($var)) {
 135          $a = get_object_vars($var);
 136          foreach ($a as $key => $value) {
 137              $a[$key] = addslashes_js($value);
 138          }
 139          $var = (object)$a;
 140      }
 141      return $var;
 142  }
 143  
 144  /**
 145   * Remove query string from url.
 146   *
 147   * Takes in a URL and returns it without the querystring portion.
 148   *
 149   * @param string $url the url which may have a query string attached.
 150   * @return string The remaining URL.
 151   */
 152  function strip_querystring($url) {
 153  
 154      if ($commapos = strpos($url, '?')) {
 155          return substr($url, 0, $commapos);
 156      } else {
 157          return $url;
 158      }
 159  }
 160  
 161  /**
 162   * Returns the name of the current script, WITH the querystring portion.
 163   *
 164   * This function is necessary because PHP_SELF and REQUEST_URI and SCRIPT_NAME
 165   * return different things depending on a lot of things like your OS, Web
 166   * server, and the way PHP is compiled (ie. as a CGI, module, ISAPI, etc.)
 167   * <b>NOTE:</b> This function returns false if the global variables needed are not set.
 168   *
 169   * @return mixed String or false if the global variables needed are not set.
 170   */
 171  function me() {
 172      global $ME;
 173      return $ME;
 174  }
 175  
 176  /**
 177   * Guesses the full URL of the current script.
 178   *
 179   * This function is using $PAGE->url, but may fall back to $FULLME which
 180   * is constructed from  PHP_SELF and REQUEST_URI or SCRIPT_NAME
 181   *
 182   * @return mixed full page URL string or false if unknown
 183   */
 184  function qualified_me() {
 185      global $FULLME, $PAGE, $CFG;
 186  
 187      if (isset($PAGE) and $PAGE->has_set_url()) {
 188          // This is the only recommended way to find out current page.
 189          return $PAGE->url->out(false);
 190  
 191      } else {
 192          if ($FULLME === null) {
 193              // CLI script most probably.
 194              return false;
 195          }
 196          if (!empty($CFG->sslproxy)) {
 197              // Return only https links when using SSL proxy.
 198              return preg_replace('/^http:/', 'https:', $FULLME, 1);
 199          } else {
 200              return $FULLME;
 201          }
 202      }
 203  }
 204  
 205  /**
 206   * Determines whether or not the Moodle site is being served over HTTPS.
 207   *
 208   * This is done simply by checking the value of $CFG->httpswwwroot, which seems
 209   * to be the only reliable method.
 210   *
 211   * @return boolean True if site is served over HTTPS, false otherwise.
 212   */
 213  function is_https() {
 214      global $CFG;
 215  
 216      return (strpos($CFG->httpswwwroot, 'https://') === 0);
 217  }
 218  
 219  /**
 220   * Returns the cleaned local URL of the HTTP_REFERER less the URL query string parameters if required.
 221   *
 222   * @param bool $stripquery if true, also removes the query part of the url.
 223   * @return string The resulting referer or empty string.
 224   */
 225  function get_local_referer($stripquery = true) {
 226      if (isset($_SERVER['HTTP_REFERER'])) {
 227          $referer = clean_param($_SERVER['HTTP_REFERER'], PARAM_LOCALURL);
 228          if ($stripquery) {
 229              return strip_querystring($referer);
 230          } else {
 231              return $referer;
 232          }
 233      } else {
 234          return '';
 235      }
 236  }
 237  
 238  /**
 239   * Class for creating and manipulating urls.
 240   *
 241   * It can be used in moodle pages where config.php has been included without any further includes.
 242   *
 243   * It is useful for manipulating urls with long lists of params.
 244   * One situation where it will be useful is a page which links to itself to perform various actions
 245   * and / or to process form data. A moodle_url object :
 246   * can be created for a page to refer to itself with all the proper get params being passed from page call to
 247   * page call and methods can be used to output a url including all the params, optionally adding and overriding
 248   * params and can also be used to
 249   *     - output the url without any get params
 250   *     - and output the params as hidden fields to be output within a form
 251   *
 252   * @copyright 2007 jamiesensei
 253   * @link http://docs.moodle.org/dev/lib/weblib.php_moodle_url See short write up here
 254   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 255   * @package core
 256   */
 257  class moodle_url {
 258  
 259      /**
 260       * Scheme, ex.: http, https
 261       * @var string
 262       */
 263      protected $scheme = '';
 264  
 265      /**
 266       * Hostname.
 267       * @var string
 268       */
 269      protected $host = '';
 270  
 271      /**
 272       * Port number, empty means default 80 or 443 in case of http.
 273       * @var int
 274       */
 275      protected $port = '';
 276  
 277      /**
 278       * Username for http auth.
 279       * @var string
 280       */
 281      protected $user = '';
 282  
 283      /**
 284       * Password for http auth.
 285       * @var string
 286       */
 287      protected $pass = '';
 288  
 289      /**
 290       * Script path.
 291       * @var string
 292       */
 293      protected $path = '';
 294  
 295      /**
 296       * Optional slash argument value.
 297       * @var string
 298       */
 299      protected $slashargument = '';
 300  
 301      /**
 302       * Anchor, may be also empty, null means none.
 303       * @var string
 304       */
 305      protected $anchor = null;
 306  
 307      /**
 308       * Url parameters as associative array.
 309       * @var array
 310       */
 311      protected $params = array();
 312  
 313      /**
 314       * Create new instance of moodle_url.
 315       *
 316       * @param moodle_url|string $url - moodle_url means make a copy of another
 317       *      moodle_url and change parameters, string means full url or shortened
 318       *      form (ex.: '/course/view.php'). It is strongly encouraged to not include
 319       *      query string because it may result in double encoded values. Use the
 320       *      $params instead. For admin URLs, just use /admin/script.php, this
 321       *      class takes care of the $CFG->admin issue.
 322       * @param array $params these params override current params or add new
 323       * @param string $anchor The anchor to use as part of the URL if there is one.
 324       * @throws moodle_exception
 325       */
 326      public function __construct($url, array $params = null, $anchor = null) {
 327          global $CFG;
 328  
 329          if ($url instanceof moodle_url) {
 330              $this->scheme = $url->scheme;
 331              $this->host = $url->host;
 332              $this->port = $url->port;
 333              $this->user = $url->user;
 334              $this->pass = $url->pass;
 335              $this->path = $url->path;
 336              $this->slashargument = $url->slashargument;
 337              $this->params = $url->params;
 338              $this->anchor = $url->anchor;
 339  
 340          } else {
 341              // Detect if anchor used.
 342              $apos = strpos($url, '#');
 343              if ($apos !== false) {
 344                  $anchor = substr($url, $apos);
 345                  $anchor = ltrim($anchor, '#');
 346                  $this->set_anchor($anchor);
 347                  $url = substr($url, 0, $apos);
 348              }
 349  
 350              // Normalise shortened form of our url ex.: '/course/view.php'.
 351              if (strpos($url, '/') === 0) {
 352                  // We must not use httpswwwroot here, because it might be url of other page,
 353                  // devs have to use httpswwwroot explicitly when creating new moodle_url.
 354                  $url = $CFG->wwwroot.$url;
 355              }
 356  
 357              // Now fix the admin links if needed, no need to mess with httpswwwroot.
 358              if ($CFG->admin !== 'admin') {
 359                  if (strpos($url, "$CFG->wwwroot/admin/") === 0) {
 360                      $url = str_replace("$CFG->wwwroot/admin/", "$CFG->wwwroot/$CFG->admin/", $url);
 361                  }
 362              }
 363  
 364              // Parse the $url.
 365              $parts = parse_url($url);
 366              if ($parts === false) {
 367                  throw new moodle_exception('invalidurl');
 368              }
 369              if (isset($parts['query'])) {
 370                  // Note: the values may not be correctly decoded, url parameters should be always passed as array.
 371                  parse_str(str_replace('&amp;', '&', $parts['query']), $this->params);
 372              }
 373              unset($parts['query']);
 374              foreach ($parts as $key => $value) {
 375                  $this->$key = $value;
 376              }
 377  
 378              // Detect slashargument value from path - we do not support directory names ending with .php.
 379              $pos = strpos($this->path, '.php/');
 380              if ($pos !== false) {
 381                  $this->slashargument = substr($this->path, $pos + 4);
 382                  $this->path = substr($this->path, 0, $pos + 4);
 383              }
 384          }
 385  
 386          $this->params($params);
 387          if ($anchor !== null) {
 388              $this->anchor = (string)$anchor;
 389          }
 390      }
 391  
 392      /**
 393       * Add an array of params to the params for this url.
 394       *
 395       * The added params override existing ones if they have the same name.
 396       *
 397       * @param array $params Defaults to null. If null then returns all params.
 398       * @return array Array of Params for url.
 399       * @throws coding_exception
 400       */
 401      public function params(array $params = null) {
 402          $params = (array)$params;
 403  
 404          foreach ($params as $key => $value) {
 405              if (is_int($key)) {
 406                  throw new coding_exception('Url parameters can not have numeric keys!');
 407              }
 408              if (!is_string($value)) {
 409                  if (is_array($value)) {
 410                      throw new coding_exception('Url parameters values can not be arrays!');
 411                  }
 412                  if (is_object($value) and !method_exists($value, '__toString')) {
 413                      throw new coding_exception('Url parameters values can not be objects, unless __toString() is defined!');
 414                  }
 415              }
 416              $this->params[$key] = (string)$value;
 417          }
 418          return $this->params;
 419      }
 420  
 421      /**
 422       * Remove all params if no arguments passed.
 423       * Remove selected params if arguments are passed.
 424       *
 425       * Can be called as either remove_params('param1', 'param2')
 426       * or remove_params(array('param1', 'param2')).
 427       *
 428       * @param string[]|string $params,... either an array of param names, or 1..n string params to remove as args.
 429       * @return array url parameters
 430       */
 431      public function remove_params($params = null) {
 432          if (!is_array($params)) {
 433              $params = func_get_args();
 434          }
 435          foreach ($params as $param) {
 436              unset($this->params[$param]);
 437          }
 438          return $this->params;
 439      }
 440  
 441      /**
 442       * Remove all url parameters.
 443       *
 444       * @todo remove the unused param.
 445       * @param array $params Unused param
 446       * @return void
 447       */
 448      public function remove_all_params($params = null) {
 449          $this->params = array();
 450          $this->slashargument = '';
 451      }
 452  
 453      /**
 454       * Add a param to the params for this url.
 455       *
 456       * The added param overrides existing one if they have the same name.
 457       *
 458       * @param string $paramname name
 459       * @param string $newvalue Param value. If new value specified current value is overriden or parameter is added
 460       * @return mixed string parameter value, null if parameter does not exist
 461       */
 462      public function param($paramname, $newvalue = '') {
 463          if (func_num_args() > 1) {
 464              // Set new value.
 465              $this->params(array($paramname => $newvalue));
 466          }
 467          if (isset($this->params[$paramname])) {
 468              return $this->params[$paramname];
 469          } else {
 470              return null;
 471          }
 472      }
 473  
 474      /**
 475       * Merges parameters and validates them
 476       *
 477       * @param array $overrideparams
 478       * @return array merged parameters
 479       * @throws coding_exception
 480       */
 481      protected function merge_overrideparams(array $overrideparams = null) {
 482          $overrideparams = (array)$overrideparams;
 483          $params = $this->params;
 484          foreach ($overrideparams as $key => $value) {
 485              if (is_int($key)) {
 486                  throw new coding_exception('Overridden parameters can not have numeric keys!');
 487              }
 488              if (is_array($value)) {
 489                  throw new coding_exception('Overridden parameters values can not be arrays!');
 490              }
 491              if (is_object($value) and !method_exists($value, '__toString')) {
 492                  throw new coding_exception('Overridden parameters values can not be objects, unless __toString() is defined!');
 493              }
 494              $params[$key] = (string)$value;
 495          }
 496          return $params;
 497      }
 498  
 499      /**
 500       * Get the params as as a query string.
 501       *
 502       * This method should not be used outside of this method.
 503       *
 504       * @param bool $escaped Use &amp; as params separator instead of plain &
 505       * @param array $overrideparams params to add to the output params, these
 506       *      override existing ones with the same name.
 507       * @return string query string that can be added to a url.
 508       */
 509      public function get_query_string($escaped = true, array $overrideparams = null) {
 510          $arr = array();
 511          if ($overrideparams !== null) {
 512              $params = $this->merge_overrideparams($overrideparams);
 513          } else {
 514              $params = $this->params;
 515          }
 516          foreach ($params as $key => $val) {
 517              if (is_array($val)) {
 518                  foreach ($val as $index => $value) {
 519                      $arr[] = rawurlencode($key.'['.$index.']')."=".rawurlencode($value);
 520                  }
 521              } else {
 522                  if (isset($val) && $val !== '') {
 523                      $arr[] = rawurlencode($key)."=".rawurlencode($val);
 524                  } else {
 525                      $arr[] = rawurlencode($key);
 526                  }
 527              }
 528          }
 529          if ($escaped) {
 530              return implode('&amp;', $arr);
 531          } else {
 532              return implode('&', $arr);
 533          }
 534      }
 535  
 536      /**
 537       * Shortcut for printing of encoded URL.
 538       *
 539       * @return string
 540       */
 541      public function __toString() {
 542          return $this->out(true);
 543      }
 544  
 545      /**
 546       * Output url.
 547       *
 548       * If you use the returned URL in HTML code, you want the escaped ampersands. If you use
 549       * the returned URL in HTTP headers, you want $escaped=false.
 550       *
 551       * @param bool $escaped Use &amp; as params separator instead of plain &
 552       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 553       * @return string Resulting URL
 554       */
 555      public function out($escaped = true, array $overrideparams = null) {
 556  
 557          global $CFG;
 558  
 559          if (!is_bool($escaped)) {
 560              debugging('Escape parameter must be of type boolean, '.gettype($escaped).' given instead.');
 561          }
 562  
 563          $url = $this;
 564  
 565          // Allow url's to be rewritten by a plugin.
 566          if (isset($CFG->urlrewriteclass) && !isset($CFG->upgraderunning)) {
 567              $class = $CFG->urlrewriteclass;
 568              $pluginurl = $class::url_rewrite($url);
 569              if ($pluginurl instanceof moodle_url) {
 570                  $url = $pluginurl;
 571              }
 572          }
 573  
 574          return $url->raw_out($escaped, $overrideparams);
 575  
 576      }
 577  
 578      /**
 579       * Output url without any rewrites
 580       *
 581       * This is identical in signature and use to out() but doesn't call the rewrite handler.
 582       *
 583       * @param bool $escaped Use &amp; as params separator instead of plain &
 584       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 585       * @return string Resulting URL
 586       */
 587      public function raw_out($escaped = true, array $overrideparams = null) {
 588          if (!is_bool($escaped)) {
 589              debugging('Escape parameter must be of type boolean, '.gettype($escaped).' given instead.');
 590          }
 591  
 592          $uri = $this->out_omit_querystring().$this->slashargument;
 593  
 594          $querystring = $this->get_query_string($escaped, $overrideparams);
 595          if ($querystring !== '') {
 596              $uri .= '?' . $querystring;
 597          }
 598          if (!is_null($this->anchor)) {
 599              $uri .= '#'.$this->anchor;
 600          }
 601  
 602          return $uri;
 603      }
 604  
 605      /**
 606       * Returns url without parameters, everything before '?'.
 607       *
 608       * @param bool $includeanchor if {@link self::anchor} is defined, should it be returned?
 609       * @return string
 610       */
 611      public function out_omit_querystring($includeanchor = false) {
 612  
 613          $uri = $this->scheme ? $this->scheme.':'.((strtolower($this->scheme) == 'mailto') ? '':'//'): '';
 614          $uri .= $this->user ? $this->user.($this->pass? ':'.$this->pass:'').'@':'';
 615          $uri .= $this->host ? $this->host : '';
 616          $uri .= $this->port ? ':'.$this->port : '';
 617          $uri .= $this->path ? $this->path : '';
 618          if ($includeanchor and !is_null($this->anchor)) {
 619              $uri .= '#' . $this->anchor;
 620          }
 621  
 622          return $uri;
 623      }
 624  
 625      /**
 626       * Compares this moodle_url with another.
 627       *
 628       * See documentation of constants for an explanation of the comparison flags.
 629       *
 630       * @param moodle_url $url The moodle_url object to compare
 631       * @param int $matchtype The type of comparison (URL_MATCH_BASE, URL_MATCH_PARAMS, URL_MATCH_EXACT)
 632       * @return bool
 633       */
 634      public function compare(moodle_url $url, $matchtype = URL_MATCH_EXACT) {
 635  
 636          $baseself = $this->out_omit_querystring();
 637          $baseother = $url->out_omit_querystring();
 638  
 639          // Append index.php if there is no specific file.
 640          if (substr($baseself, -1) == '/') {
 641              $baseself .= 'index.php';
 642          }
 643          if (substr($baseother, -1) == '/') {
 644              $baseother .= 'index.php';
 645          }
 646  
 647          // Compare the two base URLs.
 648          if ($baseself != $baseother) {
 649              return false;
 650          }
 651  
 652          if ($matchtype == URL_MATCH_BASE) {
 653              return true;
 654          }
 655  
 656          $urlparams = $url->params();
 657          foreach ($this->params() as $param => $value) {
 658              if ($param == 'sesskey') {
 659                  continue;
 660              }
 661              if (!array_key_exists($param, $urlparams) || $urlparams[$param] != $value) {
 662                  return false;
 663              }
 664          }
 665  
 666          if ($matchtype == URL_MATCH_PARAMS) {
 667              return true;
 668          }
 669  
 670          foreach ($urlparams as $param => $value) {
 671              if ($param == 'sesskey') {
 672                  continue;
 673              }
 674              if (!array_key_exists($param, $this->params()) || $this->param($param) != $value) {
 675                  return false;
 676              }
 677          }
 678  
 679          if ($url->anchor !== $this->anchor) {
 680              return false;
 681          }
 682  
 683          return true;
 684      }
 685  
 686      /**
 687       * Sets the anchor for the URI (the bit after the hash)
 688       *
 689       * @param string $anchor null means remove previous
 690       */
 691      public function set_anchor($anchor) {
 692          if (is_null($anchor)) {
 693              // Remove.
 694              $this->anchor = null;
 695          } else if ($anchor === '') {
 696              // Special case, used as empty link.
 697              $this->anchor = '';
 698          } else if (preg_match('|[a-zA-Z\_\:][a-zA-Z0-9\_\-\.\:]*|', $anchor)) {
 699              // Match the anchor against the NMTOKEN spec.
 700              $this->anchor = $anchor;
 701          } else {
 702              // Bad luck, no valid anchor found.
 703              $this->anchor = null;
 704          }
 705      }
 706  
 707      /**
 708       * Sets the scheme for the URI (the bit before ://)
 709       *
 710       * @param string $scheme
 711       */
 712      public function set_scheme($scheme) {
 713          // See http://www.ietf.org/rfc/rfc3986.txt part 3.1.
 714          if (preg_match('/^[a-zA-Z][a-zA-Z0-9+.-]*$/', $scheme)) {
 715              $this->scheme = $scheme;
 716          } else {
 717              throw new coding_exception('Bad URL scheme.');
 718          }
 719      }
 720  
 721      /**
 722       * Sets the url slashargument value.
 723       *
 724       * @param string $path usually file path
 725       * @param string $parameter name of page parameter if slasharguments not supported
 726       * @param bool $supported usually null, then it depends on $CFG->slasharguments, use true or false for other servers
 727       * @return void
 728       */
 729      public function set_slashargument($path, $parameter = 'file', $supported = null) {
 730          global $CFG;
 731          if (is_null($supported)) {
 732              $supported = !empty($CFG->slasharguments);
 733          }
 734  
 735          if ($supported) {
 736              $parts = explode('/', $path);
 737              $parts = array_map('rawurlencode', $parts);
 738              $path  = implode('/', $parts);
 739              $this->slashargument = $path;
 740              unset($this->params[$parameter]);
 741  
 742          } else {
 743              $this->slashargument = '';
 744              $this->params[$parameter] = $path;
 745          }
 746      }
 747  
 748      // Static factory methods.
 749  
 750      /**
 751       * General moodle file url.
 752       *
 753       * @param string $urlbase the script serving the file
 754       * @param string $path
 755       * @param bool $forcedownload
 756       * @return moodle_url
 757       */
 758      public static function make_file_url($urlbase, $path, $forcedownload = false) {
 759          $params = array();
 760          if ($forcedownload) {
 761              $params['forcedownload'] = 1;
 762          }
 763          $url = new moodle_url($urlbase, $params);
 764          $url->set_slashargument($path);
 765          return $url;
 766      }
 767  
 768      /**
 769       * Factory method for creation of url pointing to plugin file.
 770       *
 771       * Please note this method can be used only from the plugins to
 772       * create urls of own files, it must not be used outside of plugins!
 773       *
 774       * @param int $contextid
 775       * @param string $component
 776       * @param string $area
 777       * @param int $itemid
 778       * @param string $pathname
 779       * @param string $filename
 780       * @param bool $forcedownload
 781       * @return moodle_url
 782       */
 783      public static function make_pluginfile_url($contextid, $component, $area, $itemid, $pathname, $filename,
 784                                                 $forcedownload = false) {
 785          global $CFG;
 786          $urlbase = "$CFG->httpswwwroot/pluginfile.php";
 787          if ($itemid === null) {
 788              return self::make_file_url($urlbase, "/$contextid/$component/$area".$pathname.$filename, $forcedownload);
 789          } else {
 790              return self::make_file_url($urlbase, "/$contextid/$component/$area/$itemid".$pathname.$filename, $forcedownload);
 791          }
 792      }
 793  
 794      /**
 795       * Factory method for creation of url pointing to plugin file.
 796       * This method is the same that make_pluginfile_url but pointing to the webservice pluginfile.php script.
 797       * It should be used only in external functions.
 798       *
 799       * @since  2.8
 800       * @param int $contextid
 801       * @param string $component
 802       * @param string $area
 803       * @param int $itemid
 804       * @param string $pathname
 805       * @param string $filename
 806       * @param bool $forcedownload
 807       * @return moodle_url
 808       */
 809      public static function make_webservice_pluginfile_url($contextid, $component, $area, $itemid, $pathname, $filename,
 810                                                 $forcedownload = false) {
 811          global $CFG;
 812          $urlbase = "$CFG->httpswwwroot/webservice/pluginfile.php";
 813          if ($itemid === null) {
 814              return self::make_file_url($urlbase, "/$contextid/$component/$area".$pathname.$filename, $forcedownload);
 815          } else {
 816              return self::make_file_url($urlbase, "/$contextid/$component/$area/$itemid".$pathname.$filename, $forcedownload);
 817          }
 818      }
 819  
 820      /**
 821       * Factory method for creation of url pointing to draft file of current user.
 822       *
 823       * @param int $draftid draft item id
 824       * @param string $pathname
 825       * @param string $filename
 826       * @param bool $forcedownload
 827       * @return moodle_url
 828       */
 829      public static function make_draftfile_url($draftid, $pathname, $filename, $forcedownload = false) {
 830          global $CFG, $USER;
 831          $urlbase = "$CFG->httpswwwroot/draftfile.php";
 832          $context = context_user::instance($USER->id);
 833  
 834          return self::make_file_url($urlbase, "/$context->id/user/draft/$draftid".$pathname.$filename, $forcedownload);
 835      }
 836  
 837      /**
 838       * Factory method for creating of links to legacy course files.
 839       *
 840       * @param int $courseid
 841       * @param string $filepath
 842       * @param bool $forcedownload
 843       * @return moodle_url
 844       */
 845      public static function make_legacyfile_url($courseid, $filepath, $forcedownload = false) {
 846          global $CFG;
 847  
 848          $urlbase = "$CFG->wwwroot/file.php";
 849          return self::make_file_url($urlbase, '/'.$courseid.'/'.$filepath, $forcedownload);
 850      }
 851  
 852      /**
 853       * Returns URL a relative path from $CFG->wwwroot
 854       *
 855       * Can be used for passing around urls with the wwwroot stripped
 856       *
 857       * @param boolean $escaped Use &amp; as params separator instead of plain &
 858       * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
 859       * @return string Resulting URL
 860       * @throws coding_exception if called on a non-local url
 861       */
 862      public function out_as_local_url($escaped = true, array $overrideparams = null) {
 863          global $CFG;
 864  
 865          $url = $this->out($escaped, $overrideparams);
 866          $httpswwwroot = str_replace("http://", "https://", $CFG->wwwroot);
 867  
 868          // Url should be equal to wwwroot or httpswwwroot. If not then throw exception.
 869          if (($url === $CFG->wwwroot) || (strpos($url, $CFG->wwwroot.'/') === 0)) {
 870              $localurl = substr($url, strlen($CFG->wwwroot));
 871              return !empty($localurl) ? $localurl : '';
 872          } else if (($url === $httpswwwroot) || (strpos($url, $httpswwwroot.'/') === 0)) {
 873              $localurl = substr($url, strlen($httpswwwroot));
 874              return !empty($localurl) ? $localurl : '';
 875          } else {
 876              throw new coding_exception('out_as_local_url called on a non-local URL');
 877          }
 878      }
 879  
 880      /**
 881       * Returns the 'path' portion of a URL. For example, if the URL is
 882       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 883       * return '/my/file/is/here.txt'.
 884       *
 885       * By default the path includes slash-arguments (for example,
 886       * '/myfile.php/extra/arguments') so it is what you would expect from a
 887       * URL path. If you don't want this behaviour, you can opt to exclude the
 888       * slash arguments. (Be careful: if the $CFG variable slasharguments is
 889       * disabled, these URLs will have a different format and you may need to
 890       * look at the 'file' parameter too.)
 891       *
 892       * @param bool $includeslashargument If true, includes slash arguments
 893       * @return string Path of URL
 894       */
 895      public function get_path($includeslashargument = true) {
 896          return $this->path . ($includeslashargument ? $this->slashargument : '');
 897      }
 898  
 899      /**
 900       * Returns a given parameter value from the URL.
 901       *
 902       * @param string $name Name of parameter
 903       * @return string Value of parameter or null if not set
 904       */
 905      public function get_param($name) {
 906          if (array_key_exists($name, $this->params)) {
 907              return $this->params[$name];
 908          } else {
 909              return null;
 910          }
 911      }
 912  
 913      /**
 914       * Returns the 'scheme' portion of a URL. For example, if the URL is
 915       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 916       * return 'http' (without the colon).
 917       *
 918       * @return string Scheme of the URL.
 919       */
 920      public function get_scheme() {
 921          return $this->scheme;
 922      }
 923  
 924      /**
 925       * Returns the 'host' portion of a URL. For example, if the URL is
 926       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 927       * return 'www.example.org'.
 928       *
 929       * @return string Host of the URL.
 930       */
 931      public function get_host() {
 932          return $this->host;
 933      }
 934  
 935      /**
 936       * Returns the 'port' portion of a URL. For example, if the URL is
 937       * http://www.example.org:447/my/file/is/here.txt?really=1 then this will
 938       * return '447'.
 939       *
 940       * @return string Port of the URL.
 941       */
 942      public function get_port() {
 943          return $this->port;
 944      }
 945  }
 946  
 947  /**
 948   * Determine if there is data waiting to be processed from a form
 949   *
 950   * Used on most forms in Moodle to check for data
 951   * Returns the data as an object, if it's found.
 952   * This object can be used in foreach loops without
 953   * casting because it's cast to (array) automatically
 954   *
 955   * Checks that submitted POST data exists and returns it as object.
 956   *
 957   * @return mixed false or object
 958   */
 959  function data_submitted() {
 960  
 961      if (empty($_POST)) {
 962          return false;
 963      } else {
 964          return (object)fix_utf8($_POST);
 965      }
 966  }
 967  
 968  /**
 969   * Given some normal text this function will break up any
 970   * long words to a given size by inserting the given character
 971   *
 972   * It's multibyte savvy and doesn't change anything inside html tags.
 973   *
 974   * @param string $string the string to be modified
 975   * @param int $maxsize maximum length of the string to be returned
 976   * @param string $cutchar the string used to represent word breaks
 977   * @return string
 978   */
 979  function break_up_long_words($string, $maxsize=20, $cutchar=' ') {
 980  
 981      // First of all, save all the tags inside the text to skip them.
 982      $tags = array();
 983      filter_save_tags($string, $tags);
 984  
 985      // Process the string adding the cut when necessary.
 986      $output = '';
 987      $length = core_text::strlen($string);
 988      $wordlength = 0;
 989  
 990      for ($i=0; $i<$length; $i++) {
 991          $char = core_text::substr($string, $i, 1);
 992          if ($char == ' ' or $char == "\t" or $char == "\n" or $char == "\r" or $char == "<" or $char == ">") {
 993              $wordlength = 0;
 994          } else {
 995              $wordlength++;
 996              if ($wordlength > $maxsize) {
 997                  $output .= $cutchar;
 998                  $wordlength = 0;
 999              }
1000          }
1001          $output .= $char;
1002      }
1003  
1004      // Finally load the tags back again.
1005      if (!empty($tags)) {
1006          $output = str_replace(array_keys($tags), $tags, $output);
1007      }
1008  
1009      return $output;
1010  }
1011  
1012  /**
1013   * Try and close the current window using JavaScript, either immediately, or after a delay.
1014   *
1015   * Echo's out the resulting XHTML & javascript
1016   *
1017   * @param integer $delay a delay in seconds before closing the window. Default 0.
1018   * @param boolean $reloadopener if true, we will see if this window was a pop-up, and try
1019   *      to reload the parent window before this one closes.
1020   */
1021  function close_window($delay = 0, $reloadopener = false) {
1022      global $PAGE, $OUTPUT;
1023  
1024      if (!$PAGE->headerprinted) {
1025          $PAGE->set_title(get_string('closewindow'));
1026          echo $OUTPUT->header();
1027      } else {
1028          $OUTPUT->container_end_all(false);
1029      }
1030  
1031      if ($reloadopener) {
1032          // Trigger the reload immediately, even if the reload is after a delay.
1033          $PAGE->requires->js_function_call('window.opener.location.reload', array(true));
1034      }
1035      $OUTPUT->notification(get_string('windowclosing'), 'notifysuccess');
1036  
1037      $PAGE->requires->js_function_call('close_window', array(new stdClass()), false, $delay);
1038  
1039      echo $OUTPUT->footer();
1040      exit;
1041  }
1042  
1043  /**
1044   * Returns a string containing a link to the user documentation for the current page.
1045   *
1046   * Also contains an icon by default. Shown to teachers and admin only.
1047   *
1048   * @param string $text The text to be displayed for the link
1049   * @return string The link to user documentation for this current page
1050   */
1051  function page_doc_link($text='') {
1052      global $OUTPUT, $PAGE;
1053      $path = page_get_doc_link_path($PAGE);
1054      if (!$path) {
1055          return '';
1056      }
1057      return $OUTPUT->doc_link($path, $text);
1058  }
1059  
1060  /**
1061   * Returns the path to use when constructing a link to the docs.
1062   *
1063   * @since Moodle 2.5.1 2.6
1064   * @param moodle_page $page
1065   * @return string
1066   */
1067  function page_get_doc_link_path(moodle_page $page) {
1068      global $CFG;
1069  
1070      if (empty($CFG->docroot) || during_initial_install()) {
1071          return '';
1072      }
1073      if (!has_capability('moodle/site:doclinks', $page->context)) {
1074          return '';
1075      }
1076  
1077      $path = $page->docspath;
1078      if (!$path) {
1079          return '';
1080      }
1081      return $path;
1082  }
1083  
1084  
1085  /**
1086   * Validates an email to make sure it makes sense.
1087   *
1088   * @param string $address The email address to validate.
1089   * @return boolean
1090   */
1091  function validate_email($address) {
1092  
1093      return (preg_match('#^[-!\#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+'.
1094                   '(\.[-!\#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+)*'.
1095                    '@'.
1096                    '[-!\#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+\.'.
1097                    '[-!\#$%&\'*+\\./0-9=?A-Z^_`a-z{|}~]+$#',
1098                    $address));
1099  }
1100  
1101  /**
1102   * Extracts file argument either from file parameter or PATH_INFO
1103   *
1104   * Note: $scriptname parameter is not needed anymore
1105   *
1106   * @return string file path (only safe characters)
1107   */
1108  function get_file_argument() {
1109      global $SCRIPT;
1110  
1111      $relativepath = optional_param('file', false, PARAM_PATH);
1112  
1113      if ($relativepath !== false and $relativepath !== '') {
1114          return $relativepath;
1115      }
1116      $relativepath = false;
1117  
1118      // Then try extract file from the slasharguments.
1119      if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
1120          // NOTE: IIS tends to convert all file paths to single byte DOS encoding,
1121          //       we can not use other methods because they break unicode chars,
1122          //       the only ways are to use URL rewriting
1123          //       OR
1124          //       to properly set the 'FastCGIUtf8ServerVariables' registry key.
1125          if (isset($_SERVER['PATH_INFO']) and $_SERVER['PATH_INFO'] !== '') {
1126              // Check that PATH_INFO works == must not contain the script name.
1127              if (strpos($_SERVER['PATH_INFO'], $SCRIPT) === false) {
1128                  $relativepath = clean_param(urldecode($_SERVER['PATH_INFO']), PARAM_PATH);
1129              }
1130          }
1131      } else {
1132          // All other apache-like servers depend on PATH_INFO.
1133          if (isset($_SERVER['PATH_INFO'])) {
1134              if (isset($_SERVER['SCRIPT_NAME']) and strpos($_SERVER['PATH_INFO'], $_SERVER['SCRIPT_NAME']) === 0) {
1135                  $relativepath = substr($_SERVER['PATH_INFO'], strlen($_SERVER['SCRIPT_NAME']));
1136              } else {
1137                  $relativepath = $_SERVER['PATH_INFO'];
1138              }
1139              $relativepath = clean_param($relativepath, PARAM_PATH);
1140          }
1141      }
1142  
1143      return $relativepath;
1144  }
1145  
1146  /**
1147   * Just returns an array of text formats suitable for a popup menu
1148   *
1149   * @return array
1150   */
1151  function format_text_menu() {
1152      return array (FORMAT_MOODLE => get_string('formattext'),
1153                    FORMAT_HTML => get_string('formathtml'),
1154                    FORMAT_PLAIN => get_string('formatplain'),
1155                    FORMAT_MARKDOWN => get_string('formatmarkdown'));
1156  }
1157  
1158  /**
1159   * Given text in a variety of format codings, this function returns the text as safe HTML.
1160   *
1161   * This function should mainly be used for long strings like posts,
1162   * answers, glossary items etc. For short strings {@link format_string()}.
1163   *
1164   * <pre>
1165   * Options:
1166   *      trusted     :   If true the string won't be cleaned. Default false required noclean=true.
1167   *      noclean     :   If true the string won't be cleaned. Default false required trusted=true.
1168   *      nocache     :   If true the strign will not be cached and will be formatted every call. Default false.
1169   *      filter      :   If true the string will be run through applicable filters as well. Default true.
1170   *      para        :   If true then the returned string will be wrapped in div tags. Default true.
1171   *      newlines    :   If true then lines newline breaks will be converted to HTML newline breaks. Default true.
1172   *      context     :   The context that will be used for filtering.
1173   *      overflowdiv :   If set to true the formatted text will be encased in a div
1174   *                      with the class no-overflow before being returned. Default false.
1175   *      allowid     :   If true then id attributes will not be removed, even when
1176   *                      using htmlpurifier. Default false.
1177   *      blanktarget :   If true all <a> tags will have target="_blank" added unless target is explicitly specified.
1178   * </pre>
1179   *
1180   * @staticvar array $croncache
1181   * @param string $text The text to be formatted. This is raw text originally from user input.
1182   * @param int $format Identifier of the text format to be used
1183   *            [FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_MARKDOWN]
1184   * @param object/array $options text formatting options
1185   * @param int $courseiddonotuse deprecated course id, use context option instead
1186   * @return string
1187   */
1188  function format_text($text, $format = FORMAT_MOODLE, $options = null, $courseiddonotuse = null) {
1189      global $CFG, $DB, $PAGE;
1190  
1191      if ($text === '' || is_null($text)) {
1192          // No need to do any filters and cleaning.
1193          return '';
1194      }
1195  
1196      // Detach object, we can not modify it.
1197      $options = (array)$options;
1198  
1199      if (!isset($options['trusted'])) {
1200          $options['trusted'] = false;
1201      }
1202      if (!isset($options['noclean'])) {
1203          if ($options['trusted'] and trusttext_active()) {
1204              // No cleaning if text trusted and noclean not specified.
1205              $options['noclean'] = true;
1206          } else {
1207              $options['noclean'] = false;
1208          }
1209      }
1210      if (!isset($options['nocache'])) {
1211          $options['nocache'] = false;
1212      }
1213      if (!isset($options['filter'])) {
1214          $options['filter'] = true;
1215      }
1216      if (!isset($options['para'])) {
1217          $options['para'] = true;
1218      }
1219      if (!isset($options['newlines'])) {
1220          $options['newlines'] = true;
1221      }
1222      if (!isset($options['overflowdiv'])) {
1223          $options['overflowdiv'] = false;
1224      }
1225      $options['blanktarget'] = !empty($options['blanktarget']);
1226  
1227      // Calculate best context.
1228      if (empty($CFG->version) or $CFG->version < 2013051400 or during_initial_install()) {
1229          // Do not filter anything during installation or before upgrade completes.
1230          $context = null;
1231  
1232      } else if (isset($options['context'])) { // First by explicit passed context option.
1233          if (is_object($options['context'])) {
1234              $context = $options['context'];
1235          } else {
1236              $context = context::instance_by_id($options['context']);
1237          }
1238      } else if ($courseiddonotuse) {
1239          // Legacy courseid.
1240          $context = context_course::instance($courseiddonotuse);
1241      } else {
1242          // Fallback to $PAGE->context this may be problematic in CLI and other non-standard pages :-(.
1243          $context = $PAGE->context;
1244      }
1245  
1246      if (!$context) {
1247          // Either install/upgrade or something has gone really wrong because context does not exist (yet?).
1248          $options['nocache'] = true;
1249          $options['filter']  = false;
1250      }
1251  
1252      if ($options['filter']) {
1253          $filtermanager = filter_manager::instance();
1254          $filtermanager->setup_page_for_filters($PAGE, $context); // Setup global stuff filters may have.
1255          $filteroptions = array(
1256              'originalformat' => $format,
1257              'noclean' => $options['noclean'],
1258          );
1259      } else {
1260          $filtermanager = new null_filter_manager();
1261          $filteroptions = array();
1262      }
1263  
1264      switch ($format) {
1265          case FORMAT_HTML:
1266              if (!$options['noclean']) {
1267                  $text = clean_text($text, FORMAT_HTML, $options);
1268              }
1269              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1270              break;
1271  
1272          case FORMAT_PLAIN:
1273              $text = s($text); // Cleans dangerous JS.
1274              $text = rebuildnolinktag($text);
1275              $text = str_replace('  ', '&nbsp; ', $text);
1276              $text = nl2br($text);
1277              break;
1278  
1279          case FORMAT_WIKI:
1280              // This format is deprecated.
1281              $text = '<p>NOTICE: Wiki-like formatting has been removed from Moodle.  You should not be seeing
1282                       this message as all texts should have been converted to Markdown format instead.
1283                       Please post a bug report to http://moodle.org/bugs with information about where you
1284                       saw this message.</p>'.s($text);
1285              break;
1286  
1287          case FORMAT_MARKDOWN:
1288              $text = markdown_to_html($text);
1289              if (!$options['noclean']) {
1290                  $text = clean_text($text, FORMAT_HTML, $options);
1291              }
1292              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1293              break;
1294  
1295          default:  // FORMAT_MOODLE or anything else.
1296              $text = text_to_html($text, null, $options['para'], $options['newlines']);
1297              if (!$options['noclean']) {
1298                  $text = clean_text($text, FORMAT_HTML, $options);
1299              }
1300              $text = $filtermanager->filter_text($text, $context, $filteroptions);
1301              break;
1302      }
1303      if ($options['filter']) {
1304          // At this point there should not be any draftfile links any more,
1305          // this happens when developers forget to post process the text.
1306          // The only potential problem is that somebody might try to format
1307          // the text before storing into database which would be itself big bug..
1308          $text = str_replace("\"$CFG->httpswwwroot/draftfile.php", "\"$CFG->httpswwwroot/brokenfile.php#", $text);
1309  
1310          if ($CFG->debugdeveloper) {
1311              if (strpos($text, '@@PLUGINFILE@@/') !== false) {
1312                  debugging('Before calling format_text(), the content must be processed with file_rewrite_pluginfile_urls()',
1313                      DEBUG_DEVELOPER);
1314              }
1315          }
1316      }
1317  
1318      if (!empty($options['overflowdiv'])) {
1319          $text = html_writer::tag('div', $text, array('class' => 'no-overflow'));
1320      }
1321  
1322      if ($options['blanktarget']) {
1323          $domdoc = new DOMDocument();
1324          $domdoc->loadHTML('<?xml version="1.0" encoding="UTF-8" ?>' . $text);
1325          foreach ($domdoc->getElementsByTagName('a') as $link) {
1326              if ($link->hasAttribute('target') && strpos($link->getAttribute('target'), '_blank') === false) {
1327                  continue;
1328              }
1329              $link->setAttribute('target', '_blank');
1330              if (strpos($link->getAttribute('rel'), 'noreferrer') === false) {
1331                  $link->setAttribute('rel', trim($link->getAttribute('rel') . ' noreferrer'));
1332              }
1333          }
1334  
1335          // This regex is nasty and I don't like it. The correct way to solve this is by loading the HTML like so:
1336          // $domdoc->loadHTML($text, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD); however it seems like the libxml
1337          // version that travis uses doesn't work properly and ends up leaving <html><body>, so I'm forced to use
1338          // this regex to remove those tags.
1339          $text = trim(preg_replace('~<(?:!DOCTYPE|/?(?:html|body))[^>]*>\s*~i', '', $domdoc->saveHTML($domdoc->documentElement)));
1340      }
1341  
1342      return $text;
1343  }
1344  
1345  /**
1346   * Resets some data related to filters, called during upgrade or when general filter settings change.
1347   *
1348   * @param bool $phpunitreset true means called from our PHPUnit integration test reset
1349   * @return void
1350   */
1351  function reset_text_filters_cache($phpunitreset = false) {
1352      global $CFG, $DB;
1353  
1354      if ($phpunitreset) {
1355          // HTMLPurifier does not change, DB is already reset to defaults,
1356          // nothing to do here, the dataroot was cleared too.
1357          return;
1358      }
1359  
1360      // The purge_all_caches() deals with cachedir and localcachedir purging,
1361      // the individual filter caches are invalidated as necessary elsewhere.
1362  
1363      // Update $CFG->filterall cache flag.
1364      if (empty($CFG->stringfilters)) {
1365          set_config('filterall', 0);
1366          return;
1367      }
1368      $installedfilters = core_component::get_plugin_list('filter');
1369      $filters = explode(',', $CFG->stringfilters);
1370      foreach ($filters as $filter) {
1371          if (isset($installedfilters[$filter])) {
1372              set_config('filterall', 1);
1373              return;
1374          }
1375      }
1376      set_config('filterall', 0);
1377  }
1378  
1379  /**
1380   * Given a simple string, this function returns the string
1381   * processed by enabled string filters if $CFG->filterall is enabled
1382   *
1383   * This function should be used to print short strings (non html) that
1384   * need filter processing e.g. activity titles, post subjects,
1385   * glossary concepts.
1386   *
1387   * @staticvar bool $strcache
1388   * @param string $string The string to be filtered. Should be plain text, expect
1389   * possibly for multilang tags.
1390   * @param boolean $striplinks To strip any link in the result text. Moodle 1.8 default changed from false to true! MDL-8713
1391   * @param array $options options array/object or courseid
1392   * @return string
1393   */
1394  function format_string($string, $striplinks = true, $options = null) {
1395      global $CFG, $PAGE;
1396  
1397      // We'll use a in-memory cache here to speed up repeated strings.
1398      static $strcache = false;
1399  
1400      if (empty($CFG->version) or $CFG->version < 2013051400 or during_initial_install()) {
1401          // Do not filter anything during installation or before upgrade completes.
1402          return $string = strip_tags($string);
1403      }
1404  
1405      if ($strcache === false or count($strcache) > 2000) {
1406          // This number might need some tuning to limit memory usage in cron.
1407          $strcache = array();
1408      }
1409  
1410      if (is_numeric($options)) {
1411          // Legacy courseid usage.
1412          $options  = array('context' => context_course::instance($options));
1413      } else {
1414          // Detach object, we can not modify it.
1415          $options = (array)$options;
1416      }
1417  
1418      if (empty($options['context'])) {
1419          // Fallback to $PAGE->context this may be problematic in CLI and other non-standard pages :-(.
1420          $options['context'] = $PAGE->context;
1421      } else if (is_numeric($options['context'])) {
1422          $options['context'] = context::instance_by_id($options['context']);
1423      }
1424      if (!isset($options['filter'])) {
1425          $options['filter'] = true;
1426      }
1427  
1428      $options['escape'] = !isset($options['escape']) || $options['escape'];
1429  
1430      if (!$options['context']) {
1431          // We did not find any context? weird.
1432          return $string = strip_tags($string);
1433      }
1434  
1435      // Calculate md5.
1436      $md5 = md5($string.'<+>'.$striplinks.'<+>'.$options['context']->id.'<+>'.$options['escape'].'<+>'.current_language());
1437  
1438      // Fetch from cache if possible.
1439      if (isset($strcache[$md5])) {
1440          return $strcache[$md5];
1441      }
1442  
1443      // First replace all ampersands not followed by html entity code
1444      // Regular expression moved to its own method for easier unit testing.
1445      $string = $options['escape'] ? replace_ampersands_not_followed_by_entity($string) : $string;
1446  
1447      if (!empty($CFG->filterall) && $options['filter']) {
1448          $filtermanager = filter_manager::instance();
1449          $filtermanager->setup_page_for_filters($PAGE, $options['context']); // Setup global stuff filters may have.
1450          $string = $filtermanager->filter_string($string, $options['context']);
1451      }
1452  
1453      // If the site requires it, strip ALL tags from this string.
1454      if (!empty($CFG->formatstringstriptags)) {
1455          if ($options['escape']) {
1456              $string = str_replace(array('<', '>'), array('&lt;', '&gt;'), strip_tags($string));
1457          } else {
1458              $string = strip_tags($string);
1459          }
1460      } else {
1461          // Otherwise strip just links if that is required (default).
1462          if ($striplinks) {
1463              // Strip links in string.
1464              $string = strip_links($string);
1465          }
1466          $string = clean_text($string);
1467      }
1468  
1469      // Store to cache.
1470      $strcache[$md5] = $string;
1471  
1472      return $string;
1473  }
1474  
1475  /**
1476   * Given a string, performs a negative lookahead looking for any ampersand character
1477   * that is not followed by a proper HTML entity. If any is found, it is replaced
1478   * by &amp;. The string is then returned.
1479   *
1480   * @param string $string
1481   * @return string
1482   */
1483  function replace_ampersands_not_followed_by_entity($string) {
1484      return preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&amp;", $string);
1485  }
1486  
1487  /**
1488   * Given a string, replaces all <a>.*</a> by .* and returns the string.
1489   *
1490   * @param string $string
1491   * @return string
1492   */
1493  function strip_links($string) {
1494      return preg_replace('/(<a\s[^>]+?>)(.+?)(<\/a>)/is', '$2', $string);
1495  }
1496  
1497  /**
1498   * This expression turns links into something nice in a text format. (Russell Jungwirth)
1499   *
1500   * @param string $string
1501   * @return string
1502   */
1503  function wikify_links($string) {
1504      return preg_replace('~(<a [^<]*href=["|\']?([^ "\']*)["|\']?[^>]*>([^<]*)</a>)~i', '$3 [ $2 ]', $string);
1505  }
1506  
1507  /**
1508   * Given text in a variety of format codings, this function returns the text as plain text suitable for plain email.
1509   *
1510   * @param string $text The text to be formatted. This is raw text originally from user input.
1511   * @param int $format Identifier of the text format to be used
1512   *            [FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_WIKI, FORMAT_MARKDOWN]
1513   * @return string
1514   */
1515  function format_text_email($text, $format) {
1516  
1517      switch ($format) {
1518  
1519          case FORMAT_PLAIN:
1520              return $text;
1521              break;
1522  
1523          case FORMAT_WIKI:
1524              // There should not be any of these any more!
1525              $text = wikify_links($text);
1526              return core_text::entities_to_utf8(strip_tags($text), true);
1527              break;
1528  
1529          case FORMAT_HTML:
1530              return html_to_text($text);
1531              break;
1532  
1533          case FORMAT_MOODLE:
1534          case FORMAT_MARKDOWN:
1535          default:
1536              $text = wikify_links($text);
1537              return core_text::entities_to_utf8(strip_tags($text), true);
1538              break;
1539      }
1540  }
1541  
1542  /**
1543   * Formats activity intro text
1544   *
1545   * @param string $module name of module
1546   * @param object $activity instance of activity
1547   * @param int $cmid course module id
1548   * @param bool $filter filter resulting html text
1549   * @return string
1550   */
1551  function format_module_intro($module, $activity, $cmid, $filter=true) {
1552      global $CFG;
1553      require_once("$CFG->libdir/filelib.php");
1554      $context = context_module::instance($cmid);
1555      $options = array('noclean' => true, 'para' => false, 'filter' => $filter, 'context' => $context, 'overflowdiv' => true);
1556      $intro = file_rewrite_pluginfile_urls($activity->intro, 'pluginfile.php', $context->id, 'mod_'.$module, 'intro', null);
1557      return trim(format_text($intro, $activity->introformat, $options, null));
1558  }
1559  
1560  /**
1561   * Removes the usage of Moodle files from a text.
1562   *
1563   * In some rare cases we need to re-use a text that already has embedded links
1564   * to some files hosted within Moodle. But the new area in which we will push
1565   * this content does not support files... therefore we need to remove those files.
1566   *
1567   * @param string $source The text
1568   * @return string The stripped text
1569   */
1570  function strip_pluginfile_content($source) {
1571      $baseurl = '@@PLUGINFILE@@';
1572      // Looking for something like < .* "@@pluginfile@@.*" .* >
1573      $pattern = '$<[^<>]+["\']' . $baseurl . '[^"\']*["\'][^<>]*>$';
1574      $stripped = preg_replace($pattern, '', $source);
1575      // Use purify html to rebalence potentially mismatched tags and generally cleanup.
1576      return purify_html($stripped);
1577  }
1578  
1579  /**
1580   * Legacy function, used for cleaning of old forum and glossary text only.
1581   *
1582   * @param string $text text that may contain legacy TRUSTTEXT marker
1583   * @return string text without legacy TRUSTTEXT marker
1584   */
1585  function trusttext_strip($text) {
1586      while (true) { // Removing nested TRUSTTEXT.
1587          $orig = $text;
1588          $text = str_replace('#####TRUSTTEXT#####', '', $text);
1589          if (strcmp($orig, $text) === 0) {
1590              return $text;
1591          }
1592      }
1593  }
1594  
1595  /**
1596   * Must be called before editing of all texts with trust flag. Removes all XSS nasties from texts stored in database if needed.
1597   *
1598   * @param stdClass $object data object with xxx, xxxformat and xxxtrust fields
1599   * @param string $field name of text field
1600   * @param context $context active context
1601   * @return stdClass updated $object
1602   */
1603  function trusttext_pre_edit($object, $field, $context) {
1604      $trustfield  = $field.'trust';
1605      $formatfield = $field.'format';
1606  
1607      if (!$object->$trustfield or !trusttext_trusted($context)) {
1608          $object->$field = clean_text($object->$field, $object->$formatfield);
1609      }
1610  
1611      return $object;
1612  }
1613  
1614  /**
1615   * Is current user trusted to enter no dangerous XSS in this context?
1616   *
1617   * Please note the user must be in fact trusted everywhere on this server!!
1618   *
1619   * @param context $context
1620   * @return bool true if user trusted
1621   */
1622  function trusttext_trusted($context) {
1623      return (trusttext_active() and has_capability('moodle/site:trustcontent', $context));
1624  }
1625  
1626  /**
1627   * Is trusttext feature active?
1628   *
1629   * @return bool
1630   */
1631  function trusttext_active() {
1632      global $CFG;
1633  
1634      return !empty($CFG->enabletrusttext);
1635  }
1636  
1637  /**
1638   * Cleans raw text removing nasties.
1639   *
1640   * Given raw text (eg typed in by a user) this function cleans it up and removes any nasty tags that could mess up
1641   * Moodle pages through XSS attacks.
1642   *
1643   * The result must be used as a HTML text fragment, this function can not cleanup random
1644   * parts of html tags such as url or src attributes.
1645   *
1646   * NOTE: the format parameter was deprecated because we can safely clean only HTML.
1647   *
1648   * @param string $text The text to be cleaned
1649   * @param int|string $format deprecated parameter, should always contain FORMAT_HTML or FORMAT_MOODLE
1650   * @param array $options Array of options; currently only option supported is 'allowid' (if true,
1651   *   does not remove id attributes when cleaning)
1652   * @return string The cleaned up text
1653   */
1654  function clean_text($text, $format = FORMAT_HTML, $options = array()) {
1655      $text = (string)$text;
1656  
1657      if ($format != FORMAT_HTML and $format != FORMAT_HTML) {
1658          // TODO: we need to standardise cleanup of text when loading it into editor first.
1659          // debugging('clean_text() is designed to work only with html');.
1660      }
1661  
1662      if ($format == FORMAT_PLAIN) {
1663          return $text;
1664      }
1665  
1666      if (is_purify_html_necessary($text)) {
1667          $text = purify_html($text, $options);
1668      }
1669  
1670      // Originally we tried to neutralise some script events here, it was a wrong approach because
1671      // it was trivial to work around that (for example using style based XSS exploits).
1672      // We must not give false sense of security here - all developers MUST understand how to use
1673      // rawurlencode(), htmlentities(), htmlspecialchars(), p(), s(), moodle_url, html_writer and friends!!!
1674  
1675      return $text;
1676  }
1677  
1678  /**
1679   * Is it necessary to use HTMLPurifier?
1680   *
1681   * @private
1682   * @param string $text
1683   * @return bool false means html is safe and valid, true means use HTMLPurifier
1684   */
1685  function is_purify_html_necessary($text) {
1686      if ($text === '') {
1687          return false;
1688      }
1689  
1690      if ($text === (string)((int)$text)) {
1691          return false;
1692      }
1693  
1694      if (strpos($text, '&') !== false or preg_match('|<[^pesb/]|', $text)) {
1695          // We need to normalise entities or other tags except p, em, strong and br present.
1696          return true;
1697      }
1698  
1699      $altered = htmlspecialchars($text, ENT_NOQUOTES, 'UTF-8', true);
1700      if ($altered === $text) {
1701          // No < > or other special chars means this must be safe.
1702          return false;
1703      }
1704  
1705      // Let's try to convert back some safe html tags.
1706      $altered = preg_replace('|&lt;p&gt;(.*?)&lt;/p&gt;|m', '<p>$1</p>', $altered);
1707      if ($altered === $text) {
1708          return false;
1709      }
1710      $altered = preg_replace('|&lt;em&gt;([^<>]+?)&lt;/em&gt;|m', '<em>$1</em>', $altered);
1711      if ($altered === $text) {
1712          return false;
1713      }
1714      $altered = preg_replace('|&lt;strong&gt;([^<>]+?)&lt;/strong&gt;|m', '<strong>$1</strong>', $altered);
1715      if ($altered === $text) {
1716          return false;
1717      }
1718      $altered = str_replace('&lt;br /&gt;', '<br />', $altered);
1719      if ($altered === $text) {
1720          return false;
1721      }
1722  
1723      return true;
1724  }
1725  
1726  /**
1727   * KSES replacement cleaning function - uses HTML Purifier.
1728   *
1729   * @param string $text The (X)HTML string to purify
1730   * @param array $options Array of options; currently only option supported is 'allowid' (if set,
1731   *   does not remove id attributes when cleaning)
1732   * @return string
1733   */
1734  function purify_html($text, $options = array()) {
1735      global $CFG;
1736  
1737      $text = (string)$text;
1738  
1739      static $purifiers = array();
1740      static $caches = array();
1741  
1742      // Purifier code can change only during major version upgrade.
1743      $version = empty($CFG->version) ? 0 : $CFG->version;
1744      $cachedir = "$CFG->localcachedir/htmlpurifier/$version";
1745      if (!file_exists($cachedir)) {
1746          // Purging of caches may remove the cache dir at any time,
1747          // luckily file_exists() results should be cached for all existing directories.
1748          $purifiers = array();
1749          $caches = array();
1750          gc_collect_cycles();
1751  
1752          make_localcache_directory('htmlpurifier', false);
1753          check_dir_exists($cachedir);
1754      }
1755  
1756      $allowid = empty($options['allowid']) ? 0 : 1;
1757      $allowobjectembed = empty($CFG->allowobjectembed) ? 0 : 1;
1758  
1759      $type = 'type_'.$allowid.'_'.$allowobjectembed;
1760  
1761      if (!array_key_exists($type, $caches)) {
1762          $caches[$type] = cache::make('core', 'htmlpurifier', array('type' => $type));
1763      }
1764      $cache = $caches[$type];
1765  
1766      // Add revision number and all options to the text key so that it is compatible with local cluster node caches.
1767      $key = "|$version|$allowobjectembed|$allowid|$text";
1768      $filteredtext = $cache->get($key);
1769  
1770      if ($filteredtext === true) {
1771          // The filtering did not change the text last time, no need to filter anything again.
1772          return $text;
1773      } else if ($filteredtext !== false) {
1774          return $filteredtext;
1775      }
1776  
1777      if (empty($purifiers[$type])) {
1778          require_once $CFG->libdir.'/htmlpurifier/HTMLPurifier.safe-includes.php';
1779          require_once $CFG->libdir.'/htmlpurifier/locallib.php';
1780          $config = HTMLPurifier_Config::createDefault();
1781  
1782          $config->set('HTML.DefinitionID', 'moodlehtml');
1783          $config->set('HTML.DefinitionRev', 5);
1784          $config->set('Cache.SerializerPath', $cachedir);
1785          $config->set('Cache.SerializerPermissions', $CFG->directorypermissions);
1786          $config->set('Core.NormalizeNewlines', false);
1787          $config->set('Core.ConvertDocumentToFragment', true);
1788          $config->set('Core.Encoding', 'UTF-8');
1789          $config->set('HTML.Doctype', 'XHTML 1.0 Transitional');
1790          $config->set('URI.AllowedSchemes', array(
1791              'http' => true,
1792              'https' => true,
1793              'ftp' => true,
1794              'irc' => true,
1795              'nntp' => true,
1796              'news' => true,
1797              'rtsp' => true,
1798              'rtmp' => true,
1799              'teamspeak' => true,
1800              'gopher' => true,
1801              'mms' => true,
1802              'mailto' => true
1803          ));
1804          $config->set('Attr.AllowedFrameTargets', array('_blank'));
1805  
1806          if ($allowobjectembed) {
1807              $config->set('HTML.SafeObject', true);
1808              $config->set('Output.FlashCompat', true);
1809              $config->set('HTML.SafeEmbed', true);
1810          }
1811  
1812          if ($allowid) {
1813              $config->set('Attr.EnableID', true);
1814          }
1815  
1816          if ($def = $config->maybeGetRawHTMLDefinition()) {
1817              $def->addElement('nolink', 'Block', 'Flow', array());                       // Skip our filters inside.
1818              $def->addElement('tex', 'Inline', 'Inline', array());                       // Tex syntax, equivalent to $$xx$$.
1819              $def->addElement('algebra', 'Inline', 'Inline', array());                   // Algebra syntax, equivalent to @@xx@@.
1820              $def->addElement('lang', 'Block', 'Flow', array(), array('lang'=>'CDATA')); // Original multilang style - only our hacked lang attribute.
1821              $def->addAttribute('span', 'xxxlang', 'CDATA');                             // Current very problematic multilang.
1822  
1823              // Media elements.
1824              // https://html.spec.whatwg.org/#the-video-element
1825              $def->addElement('video', 'Block', 'Optional: (source, Flow) | (Flow, source) | Flow', 'Common', [
1826                  'src' => 'URI',
1827                  'crossorigin' => 'Enum#anonymous,use-credentials',
1828                  'poster' => 'URI',
1829                  'preload' => 'Enum#auto,metadata,none',
1830                  'autoplay' => 'Bool',
1831                  'playsinline' => 'Bool',
1832                  'loop' => 'Bool',
1833                  'muted' => 'Bool',
1834                  'controls' => 'Bool',
1835                  'width' => 'Length',
1836                  'height' => 'Length',
1837              ]);
1838              // https://html.spec.whatwg.org/#the-audio-element
1839              $def->addElement('audio', 'Block', 'Optional: (source, Flow) | (Flow, source) | Flow', 'Common', [
1840                  'src' => 'URI',
1841                  'crossorigin' => 'Enum#anonymous,use-credentials',
1842                  'preload' => 'Enum#auto,metadata,none',
1843                  'autoplay' => 'Bool',
1844                  'loop' => 'Bool',
1845                  'muted' => 'Bool',
1846                  'controls' => 'Bool'
1847              ]);
1848              // https://html.spec.whatwg.org/#the-source-element
1849              $def->addElement('source', 'Block', 'Flow', 'Common', [
1850                  'src' => 'URI',
1851                  'type' => 'Text'
1852              ]);
1853  
1854              // Use the built-in Ruby module to add annotation support.
1855              $def->manager->addModule(new HTMLPurifier_HTMLModule_Ruby());
1856  
1857              // Use the custom Noreferrer module.
1858              $def->manager->addModule(new HTMLPurifier_HTMLModule_Noreferrer());
1859          }
1860  
1861          $purifier = new HTMLPurifier($config);
1862          $purifiers[$type] = $purifier;
1863      } else {
1864          $purifier = $purifiers[$type];
1865      }
1866  
1867      $multilang = (strpos($text, 'class="multilang"') !== false);
1868  
1869      $filteredtext = $text;
1870      if ($multilang) {
1871          $filteredtextregex = '/<span(\s+lang="([a-zA-Z0-9_-]+)"|\s+class="multilang"){2}\s*>/';
1872          $filteredtext = preg_replace($filteredtextregex, '<span xxxlang="$2}">', $filteredtext);
1873      }
1874      $filteredtext = (string)$purifier->purify($filteredtext);
1875      if ($multilang) {
1876          $filteredtext = preg_replace('/<span xxxlang="([a-zA-Z0-9_-]+)">/', '<span lang="$1}" class="multilang">', $filteredtext);
1877      }
1878  
1879      if ($text === $filteredtext) {
1880          // No need to store the filtered text, next time we will just return unfiltered text
1881          // because it was not changed by purifying.
1882          $cache->set($key, true);
1883      } else {
1884          $cache->set($key, $filteredtext);
1885      }
1886  
1887      return $filteredtext;
1888  }
1889  
1890  /**
1891   * Given plain text, makes it into HTML as nicely as possible.
1892   *
1893   * May contain HTML tags already.
1894   *
1895   * Do not abuse this function. It is intended as lower level formatting feature used
1896   * by {@link format_text()} to convert FORMAT_MOODLE to HTML. You are supposed
1897   * to call format_text() in most of cases.
1898   *
1899   * @param string $text The string to convert.
1900   * @param boolean $smileyignored Was used to determine if smiley characters should convert to smiley images, ignored now
1901   * @param boolean $para If true then the returned string will be wrapped in div tags
1902   * @param boolean $newlines If true then lines newline breaks will be converted to HTML newline breaks.
1903   * @return string
1904   */
1905  function text_to_html($text, $smileyignored = null, $para = true, $newlines = true) {
1906      // Remove any whitespace that may be between HTML tags.
1907      $text = preg_replace("~>([[:space:]]+)<~i", "><", $text);
1908  
1909      // Remove any returns that precede or follow HTML tags.
1910      $text = preg_replace("~([\n\r])<~i", " <", $text);
1911      $text = preg_replace("~>([\n\r])~i", "> ", $text);
1912  
1913      // Make returns into HTML newlines.
1914      if ($newlines) {
1915          $text = nl2br($text);
1916      }
1917  
1918      // Wrap the whole thing in a div if required.
1919      if ($para) {
1920          // In 1.9 this was changed from a p => div.
1921          return '<div class="text_to_html">'.$text.'</div>';
1922      } else {
1923          return $text;
1924      }
1925  }
1926  
1927  /**
1928   * Given Markdown formatted text, make it into XHTML using external function
1929   *
1930   * @param string $text The markdown formatted text to be converted.
1931   * @return string Converted text
1932   */
1933  function markdown_to_html($text) {
1934      global $CFG;
1935  
1936      if ($text === '' or $text === null) {
1937          return $text;
1938      }
1939  
1940      require_once($CFG->libdir .'/markdown/MarkdownInterface.php');
1941      require_once($CFG->libdir .'/markdown/Markdown.php');
1942      require_once($CFG->libdir .'/markdown/MarkdownExtra.php');
1943  
1944      return \Michelf\MarkdownExtra::defaultTransform($text);
1945  }
1946  
1947  /**
1948   * Given HTML text, make it into plain text using external function
1949   *
1950   * @param string $html The text to be converted.
1951   * @param integer $width Width to wrap the text at. (optional, default 75 which
1952   *      is a good value for email. 0 means do not limit line length.)
1953   * @param boolean $dolinks By default, any links in the HTML are collected, and
1954   *      printed as a list at the end of the HTML. If you don't want that, set this
1955   *      argument to false.
1956   * @return string plain text equivalent of the HTML.
1957   */
1958  function html_to_text($html, $width = 75, $dolinks = true) {
1959      global $CFG;
1960  
1961      require_once($CFG->libdir .'/html2text/lib.php');
1962  
1963      $options = array(
1964          'width'     => $width,
1965          'do_links'  => 'table',
1966      );
1967  
1968      if (empty($dolinks)) {
1969          $options['do_links'] = 'none';
1970      }
1971      $h2t = new core_html2text($html, $options);
1972      $result = $h2t->getText();
1973  
1974      return $result;
1975  }
1976  
1977  /**
1978   * Converts texts or strings to plain text.
1979   *
1980   * - When used to convert user input introduced in an editor the text format needs to be passed in $contentformat like we usually
1981   *   do in format_text.
1982   * - When this function is used for strings that are usually passed through format_string before displaying them
1983   *   we need to set $contentformat to false. This will execute html_to_text as these strings can contain multilang tags if
1984   *   multilang filter is applied to headings.
1985   *
1986   * @param string $content The text as entered by the user
1987   * @param int|false $contentformat False for strings or the text format: FORMAT_MOODLE/FORMAT_HTML/FORMAT_PLAIN/FORMAT_MARKDOWN
1988   * @return string Plain text.
1989   */
1990  function content_to_text($content, $contentformat) {
1991  
1992      switch ($contentformat) {
1993          case FORMAT_PLAIN:
1994              // Nothing here.
1995              break;
1996          case FORMAT_MARKDOWN:
1997              $content = markdown_to_html($content);
1998              $content = html_to_text($content, 75, false);
1999              break;
2000          default:
2001              // FORMAT_HTML, FORMAT_MOODLE and $contentformat = false, the later one are strings usually formatted through
2002              // format_string, we need to convert them from html because they can contain HTML (multilang filter).
2003              $content = html_to_text($content, 75, false);
2004      }
2005  
2006      return trim($content, "\r\n ");
2007  }
2008  
2009  /**
2010   * This function will highlight search words in a given string
2011   *
2012   * It cares about HTML and will not ruin links.  It's best to use
2013   * this function after performing any conversions to HTML.
2014   *
2015   * @param string $needle The search string. Syntax like "word1 +word2 -word3" is dealt with correctly.
2016   * @param string $haystack The string (HTML) within which to highlight the search terms.
2017   * @param boolean $matchcase whether to do case-sensitive. Default case-insensitive.
2018   * @param string $prefix the string to put before each search term found.
2019   * @param string $suffix the string to put after each search term found.
2020   * @return string The highlighted HTML.
2021   */
2022  function highlight($needle, $haystack, $matchcase = false,
2023          $prefix = '<span class="highlight">', $suffix = '</span>') {
2024  
2025      // Quick bail-out in trivial cases.
2026      if (empty($needle) or empty($haystack)) {
2027          return $haystack;
2028      }
2029  
2030      // Break up the search term into words, discard any -words and build a regexp.
2031      $words = preg_split('/ +/', trim($needle));
2032      foreach ($words as $index => $word) {
2033          if (strpos($word, '-') === 0) {
2034              unset($words[$index]);
2035          } else if (strpos($word, '+') === 0) {
2036              $words[$index] = '\b' . preg_quote(ltrim($word, '+'), '/') . '\b'; // Match only as a complete word.
2037          } else {
2038              $words[$index] = preg_quote($word, '/');
2039          }
2040      }
2041      $regexp = '/(' . implode('|', $words) . ')/u'; // Char u is to do UTF-8 matching.
2042      if (!$matchcase) {
2043          $regexp .= 'i';
2044      }
2045  
2046      // Another chance to bail-out if $search was only -words.
2047      if (empty($words)) {
2048          return $haystack;
2049      }
2050  
2051      // Split the string into HTML tags and real content.
2052      $chunks = preg_split('/((?:<[^>]*>)+)/', $haystack, -1, PREG_SPLIT_DELIM_CAPTURE);
2053  
2054      // We have an array of alternating blocks of text, then HTML tags, then text, ...
2055      // Loop through replacing search terms in the text, and leaving the HTML unchanged.
2056      $ishtmlchunk = false;
2057      $result = '';
2058      foreach ($chunks as $chunk) {
2059          if ($ishtmlchunk) {
2060              $result .= $chunk;
2061          } else {
2062              $result .= preg_replace($regexp, $prefix . '$1' . $suffix, $chunk);
2063          }
2064          $ishtmlchunk = !$ishtmlchunk;
2065      }
2066  
2067      return $result;
2068  }
2069  
2070  /**
2071   * This function will highlight instances of $needle in $haystack
2072   *
2073   * It's faster that the above function {@link highlight()} and doesn't care about
2074   * HTML or anything.
2075   *
2076   * @param string $needle The string to search for
2077   * @param string $haystack The string to search for $needle in
2078   * @return string The highlighted HTML
2079   */
2080  function highlightfast($needle, $haystack) {
2081  
2082      if (empty($needle) or empty($haystack)) {
2083          return $haystack;
2084      }
2085  
2086      $parts = explode(core_text::strtolower($needle), core_text::strtolower($haystack));
2087  
2088      if (count($parts) === 1) {
2089          return $haystack;
2090      }
2091  
2092      $pos = 0;
2093  
2094      foreach ($parts as $key => $part) {
2095          $parts[$key] = substr($haystack, $pos, strlen($part));
2096          $pos += strlen($part);
2097  
2098          $parts[$key] .= '<span class="highlight">'.substr($haystack, $pos, strlen($needle)).'</span>';
2099          $pos += strlen($needle);
2100      }
2101  
2102      return str_replace('<span class="highlight"></span>', '', join('', $parts));
2103  }
2104  
2105  /**
2106   * Return a string containing 'lang', xml:lang and optionally 'dir' HTML attributes.
2107   *
2108   * Internationalisation, for print_header and backup/restorelib.
2109   *
2110   * @param bool $dir Default false
2111   * @return string Attributes
2112   */
2113  function get_html_lang($dir = false) {
2114      $direction = '';
2115      if ($dir) {
2116          if (right_to_left()) {
2117              $direction = ' dir="rtl"';
2118          } else {
2119              $direction = ' dir="ltr"';
2120          }
2121      }
2122      // Accessibility: added the 'lang' attribute to $direction, used in theme <html> tag.
2123      $language = str_replace('_', '-', current_language());
2124      @header('Content-Language: '.$language);
2125      return ($direction.' lang="'.$language.'" xml:lang="'.$language.'"');
2126  }
2127  
2128  
2129  // STANDARD WEB PAGE PARTS.
2130  
2131  /**
2132   * Send the HTTP headers that Moodle requires.
2133   *
2134   * There is a backwards compatibility hack for legacy code
2135   * that needs to add custom IE compatibility directive.
2136   *
2137   * Example:
2138   * <code>
2139   * if (!isset($CFG->additionalhtmlhead)) {
2140   *     $CFG->additionalhtmlhead = '';
2141   * }
2142   * $CFG->additionalhtmlhead .= '<meta http-equiv="X-UA-Compatible" content="IE=8" />';
2143   * header('X-UA-Compatible: IE=8');
2144   * echo $OUTPUT->header();
2145   * </code>
2146   *
2147   * Please note the $CFG->additionalhtmlhead alone might not work,
2148   * you should send the IE compatibility header() too.
2149   *
2150   * @param string $contenttype
2151   * @param bool $cacheable Can this page be cached on back?
2152   * @return void, sends HTTP headers
2153   */
2154  function send_headers($contenttype, $cacheable = true) {
2155      global $CFG;
2156  
2157      @header('Content-Type: ' . $contenttype);
2158      @header('Content-Script-Type: text/javascript');
2159      @header('Content-Style-Type: text/css');
2160  
2161      if (empty($CFG->additionalhtmlhead) or stripos($CFG->additionalhtmlhead, 'X-UA-Compatible') === false) {
2162          @header('X-UA-Compatible: IE=edge');
2163      }
2164  
2165      if ($cacheable) {
2166          // Allow caching on "back" (but not on normal clicks).
2167          @header('Cache-Control: private, pre-check=0, post-check=0, max-age=0, no-transform');
2168          @header('Pragma: no-cache');
2169          @header('Expires: ');
2170      } else {
2171          // Do everything we can to always prevent clients and proxies caching.
2172          @header('Cache-Control: no-store, no-cache, must-revalidate');
2173          @header('Cache-Control: post-check=0, pre-check=0, no-transform', false);
2174          @header('Pragma: no-cache');
2175          @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
2176          @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
2177      }
2178      @header('Accept-Ranges: none');
2179  
2180      if (empty($CFG->allowframembedding)) {
2181          @header('X-Frame-Options: sameorigin');
2182      }
2183  }
2184  
2185  /**
2186   * Return the right arrow with text ('next'), and optionally embedded in a link.
2187   *
2188   * @param string $text HTML/plain text label (set to blank only for breadcrumb separator cases).
2189   * @param string $url An optional link to use in a surrounding HTML anchor.
2190   * @param bool $accesshide True if text should be hidden (for screen readers only).
2191   * @param string $addclass Additional class names for the link, or the arrow character.
2192   * @return string HTML string.
2193   */
2194  function link_arrow_right($text, $url='', $accesshide=false, $addclass='') {
2195      global $OUTPUT; // TODO: move to output renderer.
2196      $arrowclass = 'arrow ';
2197      if (!$url) {
2198          $arrowclass .= $addclass;
2199      }
2200      $arrow = '<span class="'.$arrowclass.'">'.$OUTPUT->rarrow().'</span>';
2201      $htmltext = '';
2202      if ($text) {
2203          $htmltext = '<span class="arrow_text">'.$text.'</span>&nbsp;';
2204          if ($accesshide) {
2205              $htmltext = get_accesshide($htmltext);
2206          }
2207      }
2208      if ($url) {
2209          $class = 'arrow_link';
2210          if ($addclass) {
2211              $class .= ' '.$addclass;
2212          }
2213          return '<a class="'.$class.'" href="'.$url.'" title="'.preg_replace('/<.*?>/', '', $text).'">'.$htmltext.$arrow.'</a>';
2214      }
2215      return $htmltext.$arrow;
2216  }
2217  
2218  /**
2219   * Return the left arrow with text ('previous'), and optionally embedded in a link.
2220   *
2221   * @param string $text HTML/plain text label (set to blank only for breadcrumb separator cases).
2222   * @param string $url An optional link to use in a surrounding HTML anchor.
2223   * @param bool $accesshide True if text should be hidden (for screen readers only).
2224   * @param string $addclass Additional class names for the link, or the arrow character.
2225   * @return string HTML string.
2226   */
2227  function link_arrow_left($text, $url='', $accesshide=false, $addclass='') {
2228      global $OUTPUT; // TODO: move to utput renderer.
2229      $arrowclass = 'arrow ';
2230      if (! $url) {
2231          $arrowclass .= $addclass;
2232      }
2233      $arrow = '<span class="'.$arrowclass.'">'.$OUTPUT->larrow().'</span>';
2234      $htmltext = '';
2235      if ($text) {
2236          $htmltext = '&nbsp;<span class="arrow_text">'.$text.'</span>';
2237          if ($accesshide) {
2238              $htmltext = get_accesshide($htmltext);
2239          }
2240      }
2241      if ($url) {
2242          $class = 'arrow_link';
2243          if ($addclass) {
2244              $class .= ' '.$addclass;
2245          }
2246          return '<a class="'.$class.'" href="'.$url.'" title="'.preg_replace('/<.*?>/', '', $text).'">'.$arrow.$htmltext.'</a>';
2247      }
2248      return $arrow.$htmltext;
2249  }
2250  
2251  /**
2252   * Return a HTML element with the class "accesshide", for accessibility.
2253   *
2254   * Please use cautiously - where possible, text should be visible!
2255   *
2256   * @param string $text Plain text.
2257   * @param string $elem Lowercase element name, default "span".
2258   * @param string $class Additional classes for the element.
2259   * @param string $attrs Additional attributes string in the form, "name='value' name2='value2'"
2260   * @return string HTML string.
2261   */
2262  function get_accesshide($text, $elem='span', $class='', $attrs='') {
2263      return "<$elem class=\"accesshide $class\" $attrs>$text</$elem>";
2264  }
2265  
2266  /**
2267   * Return the breadcrumb trail navigation separator.
2268   *
2269   * @return string HTML string.
2270   */
2271  function get_separator() {
2272      // Accessibility: the 'hidden' slash is preferred for screen readers.
2273      return ' '.link_arrow_right($text='/', $url='', $accesshide=true, 'sep').' ';
2274  }
2275  
2276  /**
2277   * Print (or return) a collapsible region, that has a caption that can be clicked to expand or collapse the region.
2278   *
2279   * If JavaScript is off, then the region will always be expanded.
2280   *
2281   * @param string $contents the contents of the box.
2282   * @param string $classes class names added to the div that is output.
2283   * @param string $id id added to the div that is output. Must not be blank.
2284   * @param string $caption text displayed at the top. Clicking on this will cause the region to expand or contract.
2285   * @param string $userpref the name of the user preference that stores the user's preferred default state.
2286   *      (May be blank if you do not wish the state to be persisted.
2287   * @param boolean $default Initial collapsed state to use if the user_preference it not set.
2288   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2289   * @return string|void If $return is false, returns nothing, otherwise returns a string of HTML.
2290   */
2291  function print_collapsible_region($contents, $classes, $id, $caption, $userpref = '', $default = false, $return = false) {
2292      $output  = print_collapsible_region_start($classes, $id, $caption, $userpref, $default, true);
2293      $output .= $contents;
2294      $output .= print_collapsible_region_end(true);
2295  
2296      if ($return) {
2297          return $output;
2298      } else {
2299          echo $output;
2300      }
2301  }
2302  
2303  /**
2304   * Print (or return) the start of a collapsible region
2305   *
2306   * The collapsibleregion has a caption that can be clicked to expand or collapse the region. If JavaScript is off, then the region
2307   * will always be expanded.
2308   *
2309   * @param string $classes class names added to the div that is output.
2310   * @param string $id id added to the div that is output. Must not be blank.
2311   * @param string $caption text displayed at the top. Clicking on this will cause the region to expand or contract.
2312   * @param string $userpref the name of the user preference that stores the user's preferred default state.
2313   *      (May be blank if you do not wish the state to be persisted.
2314   * @param boolean $default Initial collapsed state to use if the user_preference it not set.
2315   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2316   * @return string|void if $return is false, returns nothing, otherwise returns a string of HTML.
2317   */
2318  function print_collapsible_region_start($classes, $id, $caption, $userpref = '', $default = false, $return = false) {
2319      global $PAGE;
2320  
2321      // Work out the initial state.
2322      if (!empty($userpref) and is_string($userpref)) {
2323          user_preference_allow_ajax_update($userpref, PARAM_BOOL);
2324          $collapsed = get_user_preferences($userpref, $default);
2325      } else {
2326          $collapsed = $default;
2327          $userpref = false;
2328      }
2329  
2330      if ($collapsed) {
2331          $classes .= ' collapsed';
2332      }
2333  
2334      $output = '';
2335      $output .= '<div id="' . $id . '" class="collapsibleregion ' . $classes . '">';
2336      $output .= '<div id="' . $id . '_sizer">';
2337      $output .= '<div id="' . $id . '_caption" class="collapsibleregioncaption">';
2338      $output .= $caption . ' ';
2339      $output .= '</div><div id="' . $id . '_inner" class="collapsibleregioninner">';
2340      $PAGE->requires->js_init_call('M.util.init_collapsible_region', array($id, $userpref, get_string('clicktohideshow')));
2341  
2342      if ($return) {
2343          return $output;
2344      } else {
2345          echo $output;
2346      }
2347  }
2348  
2349  /**
2350   * Close a region started with print_collapsible_region_start.
2351   *
2352   * @param boolean $return if true, return the HTML as a string, rather than printing it.
2353   * @return string|void if $return is false, returns nothing, otherwise returns a string of HTML.
2354   */
2355  function print_collapsible_region_end($return = false) {
2356      $output = '</div></div></div>';
2357  
2358      if ($return) {
2359          return $output;
2360      } else {
2361          echo $output;
2362      }
2363  }
2364  
2365  /**
2366   * Print a specified group's avatar.
2367   *
2368   * @param array|stdClass $group A single {@link group} object OR array of groups.
2369   * @param int $courseid The course ID.
2370   * @param boolean $large Default small picture, or large.
2371   * @param boolean $return If false print picture, otherwise return the output as string
2372   * @param boolean $link Enclose image in a link to view specified course?
2373   * @return string|void Depending on the setting of $return
2374   */
2375  function print_group_picture($group, $courseid, $large=false, $return=false, $link=true) {
2376      global $CFG;
2377  
2378      if (is_array($group)) {
2379          $output = '';
2380          foreach ($group as $g) {
2381              $output .= print_group_picture($g, $courseid, $large, true, $link);
2382          }
2383          if ($return) {
2384              return $output;
2385          } else {
2386              echo $output;
2387              return;
2388          }
2389      }
2390  
2391      $context = context_course::instance($courseid);
2392  
2393      // If there is no picture, do nothing.
2394      if (!$group->picture) {
2395          return '';
2396      }
2397  
2398      // If picture is hidden, only show to those with course:managegroups.
2399      if ($group->hidepicture and !has_capability('moodle/course:managegroups', $context)) {
2400          return '';
2401      }
2402  
2403      if ($link or has_capability('moodle/site:accessallgroups', $context)) {
2404          $output = '<a href="'. $CFG->wwwroot .'/user/index.php?id='. $courseid .'&amp;group='. $group->id .'">';
2405      } else {
2406          $output = '';
2407      }
2408      if ($large) {
2409          $file = 'f1';
2410      } else {
2411          $file = 'f2';
2412      }
2413  
2414      $grouppictureurl = moodle_url::make_pluginfile_url($context->id, 'group', 'icon', $group->id, '/', $file);
2415      $grouppictureurl->param('rev', $group->picture);
2416      $output .= '<img class="grouppicture" src="'.$grouppictureurl.'"'.
2417          ' alt="'.s(get_string('group').' '.$group->name).'" title="'.s($group->name).'"/>';
2418  
2419      if ($link or has_capability('moodle/site:accessallgroups', $context)) {
2420          $output .= '</a>';
2421      }
2422  
2423      if ($return) {
2424          return $output;
2425      } else {
2426          echo $output;
2427      }
2428  }
2429  
2430  
2431  /**
2432   * Display a recent activity note
2433   *
2434   * @staticvar string $strftimerecent
2435   * @param int $time A timestamp int.
2436   * @param stdClass $user A user object from the database.
2437   * @param string $text Text for display for the note
2438   * @param string $link The link to wrap around the text
2439   * @param bool $return If set to true the HTML is returned rather than echo'd
2440   * @param string $viewfullnames
2441   * @return string If $retrun was true returns HTML for a recent activity notice.
2442   */
2443  function print_recent_activity_note($time, $user, $text, $link, $return=false, $viewfullnames=null) {
2444      static $strftimerecent = null;
2445      $output = '';
2446  
2447      if (is_null($viewfullnames)) {
2448          $context = context_system::instance();
2449          $viewfullnames = has_capability('moodle/site:viewfullnames', $context);
2450      }
2451  
2452      if (is_null($strftimerecent)) {
2453          $strftimerecent = get_string('strftimerecent');
2454      }
2455  
2456      $output .= '<div class="head">';
2457      $output .= '<div class="date">'.userdate($time, $strftimerecent).'</div>';
2458      $output .= '<div class="name">'.fullname($user, $viewfullnames).'</div>';
2459      $output .= '</div>';
2460      $output .= '<div class="info"><a href="'.$link.'">'.format_string($text, true).'</a></div>';
2461  
2462      if ($return) {
2463          return $output;
2464      } else {
2465          echo $output;
2466      }
2467  }
2468  
2469  /**
2470   * Returns a popup menu with course activity modules
2471   *
2472   * Given a course this function returns a small popup menu with all the course activity modules in it, as a navigation menu
2473   * outputs a simple list structure in XHTML.
2474   * The data is taken from the serialised array stored in the course record.
2475   *
2476   * @param course $course A {@link $COURSE} object.
2477   * @param array $sections
2478   * @param course_modinfo $modinfo
2479   * @param string $strsection
2480   * @param string $strjumpto
2481   * @param int $width
2482   * @param string $cmid
2483   * @return string The HTML block
2484   */
2485  function navmenulist($course, $sections, $modinfo, $strsection, $strjumpto, $width=50, $cmid=0) {
2486  
2487      global $CFG, $OUTPUT;
2488  
2489      $section = -1;
2490      $menu = array();
2491      $doneheading = false;
2492  
2493      $courseformatoptions = course_get_format($course)->get_format_options();
2494      $coursecontext = context_course::instance($course->id);
2495  
2496      $menu[] = '<ul class="navmenulist"><li class="jumpto section"><span>'.$strjumpto.'</span><ul>';
2497      foreach ($modinfo->cms as $mod) {
2498          if (!$mod->has_view()) {
2499              // Don't show modules which you can't link to!
2500              continue;
2501          }
2502  
2503          // For course formats using 'numsections' do not show extra sections.
2504          if (isset($courseformatoptions['numsections']) && $mod->sectionnum > $courseformatoptions['numsections']) {
2505              break;
2506          }
2507  
2508          if (!$mod->uservisible) { // Do not icnlude empty sections at all.
2509              continue;
2510          }
2511  
2512          if ($mod->sectionnum >= 0 and $section != $mod->sectionnum) {
2513              $thissection = $sections[$mod->sectionnum];
2514  
2515              if ($thissection->visible or
2516                      (isset($courseformatoptions['hiddensections']) and !$courseformatoptions['hiddensections']) or
2517                      has_capability('moodle/course:viewhiddensections', $coursecontext)) {
2518                  $thissection->summary = strip_tags(format_string($thissection->summary, true));
2519                  if (!$doneheading) {
2520                      $menu[] = '</ul></li>';
2521                  }
2522                  if ($course->format == 'weeks' or empty($thissection->summary)) {
2523                      $item = $strsection ." ". $mod->sectionnum;
2524                  } else {
2525                      if (core_text::strlen($thissection->summary) < ($width-3)) {
2526                          $item = $thissection->summary;
2527                      } else {
2528                          $item = core_text::substr($thissection->summary, 0, $width).'...';
2529                      }
2530                  }
2531                  $menu[] = '<li class="section"><span>'.$item.'</span>';
2532                  $menu[] = '<ul>';
2533                  $doneheading = true;
2534  
2535                  $section = $mod->sectionnum;
2536              } else {
2537                  // No activities from this hidden section shown.
2538                  continue;
2539              }
2540          }
2541  
2542          $url = $mod->modname .'/view.php?id='. $mod->id;
2543          $mod->name = strip_tags(format_string($mod->name ,true));
2544          if (core_text::strlen($mod->name) > ($width+5)) {
2545              $mod->name = core_text::substr($mod->name, 0, $width).'...';
2546          }
2547          if (!$mod->visible) {
2548              $mod->name = '('.$mod->name.')';
2549          }
2550          $class = 'activity '.$mod->modname;
2551          $class .= ($cmid == $mod->id) ? ' selected' : '';
2552          $menu[] = '<li class="'.$class.'">'.
2553                    '<img src="'.$OUTPUT->pix_url('icon', $mod->modname) . '" alt="" />'.
2554                    '<a href="'.$CFG->wwwroot.'/mod/'.$url.'">'.$mod->name.'</a></li>';
2555      }
2556  
2557      if ($doneheading) {
2558          $menu[] = '</ul></li>';
2559      }
2560      $menu[] = '</ul></li></ul>';
2561  
2562      return implode("\n", $menu);
2563  }
2564  
2565  /**
2566   * Prints a grade menu (as part of an existing form) with help showing all possible numerical grades and scales.
2567   *
2568   * @todo Finish documenting this function
2569   * @todo Deprecate: this is only used in a few contrib modules
2570   *
2571   * @param int $courseid The course ID
2572   * @param string $name
2573   * @param string $current
2574   * @param boolean $includenograde Include those with no grades
2575   * @param boolean $return If set to true returns rather than echo's
2576   * @return string|bool Depending on value of $return
2577   */
2578  function print_grade_menu($courseid, $name, $current, $includenograde=true, $return=false) {
2579      global $OUTPUT;
2580  
2581      $output = '';
2582      $strscale = get_string('scale');
2583      $strscales = get_string('scales');
2584  
2585      $scales = get_scales_menu($courseid);
2586      foreach ($scales as $i => $scalename) {
2587          $grades[-$i] = $strscale .': '. $scalename;
2588      }
2589      if ($includenograde) {
2590          $grades[0] = get_string('nograde');
2591      }
2592      for ($i=100; $i>=1; $i--) {
2593          $grades[$i] = $i;
2594      }
2595      $output .= html_writer::select($grades, $name, $current, false);
2596  
2597      $helppix = $OUTPUT->pix_url('help');
2598      $linkobject = '<span class="helplink"><img class="iconhelp" alt="'.$strscales.'" src="'.$helppix.'" /></span>';
2599      $link = new moodle_url('/course/scales.php', array('id' => $courseid, 'list' => 1));
2600      $action = new popup_action('click', $link, 'ratingscales', array('height' => 400, 'width' => 500));
2601      $output .= $OUTPUT->action_link($link, $linkobject, $action, array('title' => $strscales));
2602  
2603      if ($return) {
2604          return $output;
2605      } else {
2606          echo $output;
2607      }
2608  }
2609  
2610  /**
2611   * Print an error to STDOUT and exit with a non-zero code. For commandline scripts.
2612   *
2613   * Default errorcode is 1.
2614   *
2615   * Very useful for perl-like error-handling:
2616   * do_somethting() or mdie("Something went wrong");
2617   *
2618   * @param string  $msg       Error message
2619   * @param integer $errorcode Error code to emit
2620   */
2621  function mdie($msg='', $errorcode=1) {
2622      trigger_error($msg);
2623      exit($errorcode);
2624  }
2625  
2626  /**
2627   * Print a message and exit.
2628   *
2629   * @param string $message The message to print in the notice
2630   * @param string $link The link to use for the continue button
2631   * @param object $course A course object. Unused.
2632   * @return void This function simply exits
2633   */
2634  function notice ($message, $link='', $course=null) {
2635      global $PAGE, $OUTPUT;
2636  
2637      $message = clean_text($message);   // In case nasties are in here.
2638  
2639      if (CLI_SCRIPT) {
2640          echo("!!$message!!\n");
2641          exit(1); // No success.
2642      }
2643  
2644      if (!$PAGE->headerprinted) {
2645          // Header not yet printed.
2646          $PAGE->set_title(get_string('notice'));
2647          echo $OUTPUT->header();
2648      } else {
2649          echo $OUTPUT->container_end_all(false);
2650      }
2651  
2652      echo $OUTPUT->box($message, 'generalbox', 'notice');
2653      echo $OUTPUT->continue_button($link);
2654  
2655      echo $OUTPUT->footer();
2656      exit(1); // General error code.
2657  }
2658  
2659  /**
2660   * Redirects the user to another page, after printing a notice.
2661   *
2662   * This function calls the OUTPUT redirect method, echo's the output and then dies to ensure nothing else happens.
2663   *
2664   * <strong>Good practice:</strong> You should call this method before starting page
2665   * output by using any of the OUTPUT methods.
2666   *
2667   * @param moodle_url|string $url A moodle_url to redirect to. Strings are not to be trusted!
2668   * @param string $message The message to display to the user
2669   * @param int $delay The delay before redirecting
2670   * @param string $messagetype The type of notification to show the message in. See constants on \core\output\notification.
2671   * @throws moodle_exception
2672   */
2673  function redirect($url, $message='', $delay=null, $messagetype = \core\output\notification::NOTIFY_INFO) {
2674      global $OUTPUT, $PAGE, $CFG;
2675  
2676      if (CLI_SCRIPT or AJAX_SCRIPT) {
2677          // This is wrong - developers should not use redirect in these scripts but it should not be very likely.
2678          throw new moodle_exception('redirecterrordetected', 'error');
2679      }
2680  
2681      if ($delay === null) {
2682          $delay = -1;
2683      }
2684  
2685      // Prevent debug errors - make sure context is properly initialised.
2686      if ($PAGE) {
2687          $PAGE->set_context(null);
2688          $PAGE->set_pagelayout('redirect');  // No header and footer needed.
2689          $PAGE->set_title(get_string('pageshouldredirect', 'moodle'));
2690      }
2691  
2692      if ($url instanceof moodle_url) {
2693          $url = $url->out(false);
2694      }
2695  
2696      $debugdisableredirect = false;
2697      do {
2698          if (defined('DEBUGGING_PRINTED')) {
2699              // Some debugging already printed, no need to look more.
2700              $debugdisableredirect = true;
2701              break;
2702          }
2703  
2704          if (core_useragent::is_msword()) {
2705              // Clicking a URL from MS Word sends a request to the server without cookies. If that
2706              // causes a redirect Word will open a browser pointing the new URL. If not, the URL that
2707              // was clicked is opened. Because the request from Word is without cookies, it almost
2708              // always results in a redirect to the login page, even if the user is logged in in their
2709              // browser. This is not what we want, so prevent the redirect for requests from Word.
2710              $debugdisableredirect = true;
2711              break;
2712          }
2713  
2714          if (empty($CFG->debugdisplay) or empty($CFG->debug)) {
2715              // No errors should be displayed.
2716              break;
2717          }
2718  
2719          if (!function_exists('error_get_last') or !$lasterror = error_get_last()) {
2720              break;
2721          }
2722  
2723          if (!($lasterror['type'] & $CFG->debug)) {
2724              // Last error not interesting.
2725              break;
2726          }
2727  
2728          // Watch out here, @hidden() errors are returned from error_get_last() too.
2729          if (headers_sent()) {
2730              // We already started printing something - that means errors likely printed.
2731              $debugdisableredirect = true;
2732              break;
2733          }
2734  
2735          if (ob_get_level() and ob_get_contents()) {
2736              // There is something waiting to be printed, hopefully it is the errors,
2737              // but it might be some error hidden by @ too - such as the timezone mess from setup.php.
2738              $debugdisableredirect = true;
2739              break;
2740          }
2741      } while (false);
2742  
2743      // Technically, HTTP/1.1 requires Location: header to contain the absolute path.
2744      // (In practice browsers accept relative paths - but still, might as well do it properly.)
2745      // This code turns relative into absolute.
2746      if (!preg_match('|^[a-z]+:|i', $url)) {
2747          // Get host name http://www.wherever.com.
2748          $hostpart = preg_replace('|^(.*?[^:/])/.*$|', '$1', $CFG->wwwroot);
2749          if (preg_match('|^/|', $url)) {
2750              // URLs beginning with / are relative to web server root so we just add them in.
2751              $url = $hostpart.$url;
2752          } else {
2753              // URLs not beginning with / are relative to path of current script, so add that on.
2754              $url = $hostpart.preg_replace('|\?.*$|', '', me()).'/../'.$url;
2755          }
2756          // Replace all ..s.
2757          while (true) {
2758              $newurl = preg_replace('|/(?!\.\.)[^/]*/\.\./|', '/', $url);
2759              if ($newurl == $url) {
2760                  break;
2761              }
2762              $url = $newurl;
2763          }
2764      }
2765  
2766      // Sanitise url - we can not rely on moodle_url or our URL cleaning
2767      // because they do not support all valid external URLs.
2768      $url = preg_replace('/[\x00-\x1F\x7F]/', '', $url);
2769      $url = str_replace('"', '%22', $url);
2770      $encodedurl = preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&amp;", $url);
2771      $encodedurl = preg_replace('/^.*href="([^"]*)".*$/', "\\1", clean_text('<a href="'.$encodedurl.'" />', FORMAT_HTML));
2772      $url = str_replace('&amp;', '&', $encodedurl);
2773  
2774      if (!empty($message)) {
2775          if (!$debugdisableredirect && !headers_sent()) {
2776              // A message has been provided, and the headers have not yet been sent.
2777              // Display the message as a notification on the subsequent page.
2778              \core\notification::add($message, $messagetype);
2779              $message = null;
2780              $delay = 0;
2781          } else {
2782              if ($delay === -1 || !is_numeric($delay)) {
2783                  $delay = 3;
2784              }
2785              $message = clean_text($message);
2786          }
2787      } else {
2788          $message = get_string('pageshouldredirect');
2789          $delay = 0;
2790      }
2791  
2792      // Make sure the session is closed properly, this prevents problems in IIS
2793      // and also some potential PHP shutdown issues.
2794      \core\session\manager::write_close();
2795  
2796      if ($delay == 0 && !$debugdisableredirect && !headers_sent()) {
2797          // 302 might not work for POST requests, 303 is ignored by obsolete clients.
2798          @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
2799          @header('Location: '.$url);
2800          echo bootstrap_renderer::plain_redirect_message($encodedurl);
2801          exit;
2802      }
2803  
2804      // Include a redirect message, even with a HTTP redirect, because that is recommended practice.
2805      if ($PAGE) {
2806          $CFG->docroot = false; // To prevent the link to moodle docs from being displayed on redirect page.
2807          echo $OUTPUT->redirect_message($encodedurl, $message, $delay, $debugdisableredirect, $messagetype);
2808          exit;
2809      } else {
2810          echo bootstrap_renderer::early_redirect_message($encodedurl, $message, $delay);
2811          exit;
2812      }
2813  }
2814  
2815  /**
2816   * Given an email address, this function will return an obfuscated version of it.
2817   *
2818   * @param string $email The email address to obfuscate
2819   * @return string The obfuscated email address
2820   */
2821  function obfuscate_email($email) {
2822      $i = 0;
2823      $length = strlen($email);
2824      $obfuscated = '';
2825      while ($i < $length) {
2826          if (rand(0, 2) && $email{$i}!='@') { // MDL-20619 some browsers have problems unobfuscating @.
2827              $obfuscated.='%'.dechex(ord($email{$i}));
2828          } else {
2829              $obfuscated.=$email{$i};
2830          }
2831          $i++;
2832      }
2833      return $obfuscated;
2834  }
2835  
2836  /**
2837   * This function takes some text and replaces about half of the characters
2838   * with HTML entity equivalents.   Return string is obviously longer.
2839   *
2840   * @param string $plaintext The text to be obfuscated
2841   * @return string The obfuscated text
2842   */
2843  function obfuscate_text($plaintext) {
2844      $i=0;
2845      $length = core_text::strlen($plaintext);
2846      $obfuscated='';
2847      $prevobfuscated = false;
2848      while ($i < $length) {
2849          $char = core_text::substr($plaintext, $i, 1);
2850          $ord = core_text::utf8ord($char);
2851          $numerical = ($ord >= ord('0')) && ($ord <= ord('9'));
2852          if ($prevobfuscated and $numerical ) {
2853              $obfuscated.='&#'.$ord.';';
2854          } else if (rand(0, 2)) {
2855              $obfuscated.='&#'.$ord.';';
2856              $prevobfuscated = true;
2857          } else {
2858              $obfuscated.=$char;
2859              $prevobfuscated = false;
2860          }
2861          $i++;
2862      }
2863      return $obfuscated;
2864  }
2865  
2866  /**
2867   * This function uses the {@link obfuscate_email()} and {@link obfuscate_text()}
2868   * to generate a fully obfuscated email link, ready to use.
2869   *
2870   * @param string $email The email address to display
2871   * @param string $label The text to displayed as hyperlink to $email
2872   * @param boolean $dimmed If true then use css class 'dimmed' for hyperlink
2873   * @param string $subject The subject of the email in the mailto link
2874   * @param string $body The content of the email in the mailto link
2875   * @return string The obfuscated mailto link
2876   */
2877  function obfuscate_mailto($email, $label='', $dimmed=false, $subject = '', $body = '') {
2878  
2879      if (empty($label)) {
2880          $label = $email;
2881      }
2882  
2883      $label = obfuscate_text($label);
2884      $email = obfuscate_email($email);
2885      $mailto = obfuscate_text('mailto');
2886      $url = new moodle_url("mailto:$email");
2887      $attrs = array();
2888  
2889      if (!empty($subject)) {
2890          $url->param('subject', format_string($subject));
2891      }
2892      if (!empty($body)) {
2893          $url->param('body', format_string($body));
2894      }
2895  
2896      // Use the obfuscated mailto.
2897      $url = preg_replace('/^mailto/', $mailto, $url->out());
2898  
2899      if ($dimmed) {
2900          $attrs['title'] = get_string('emaildisable');
2901          $attrs['class'] = 'dimmed';
2902      }
2903  
2904      return html_writer::link($url, $label, $attrs);
2905  }
2906  
2907  /**
2908   * This function is used to rebuild the <nolink> tag because some formats (PLAIN and WIKI)
2909   * will transform it to html entities
2910   *
2911   * @param string $text Text to search for nolink tag in
2912   * @return string
2913   */
2914  function rebuildnolinktag($text) {
2915  
2916      $text = preg_replace('/&lt;(\/*nolink)&gt;/i', '<$1>', $text);
2917  
2918      return $text;
2919  }
2920  
2921  /**
2922   * Prints a maintenance message from $CFG->maintenance_message or default if empty.
2923   */
2924  function print_maintenance_message() {
2925      global $CFG, $SITE, $PAGE, $OUTPUT;
2926  
2927      $PAGE->set_pagetype('maintenance-message');
2928      $PAGE->set_pagelayout('maintenance');
2929      $PAGE->set_title(strip_tags($SITE->fullname));
2930      $PAGE->set_heading($SITE->fullname);
2931      echo $OUTPUT->header();
2932      echo $OUTPUT->heading(get_string('sitemaintenance', 'admin'));
2933      if (isset($CFG->maintenance_message) and !html_is_blank($CFG->maintenance_message)) {
2934          echo $OUTPUT->box_start('maintenance_message generalbox boxwidthwide boxaligncenter');
2935          echo $CFG->maintenance_message;
2936          echo $OUTPUT->box_end();
2937      }
2938      echo $OUTPUT->footer();
2939      die;
2940  }
2941  
2942  /**
2943   * Returns a string containing a nested list, suitable for formatting into tabs with CSS.
2944   *
2945   * It is not recommended to use this function in Moodle 2.5 but it is left for backward
2946   * compartibility.
2947   *
2948   * Example how to print a single line tabs:
2949   * $rows = array(
2950   *    new tabobject(...),
2951   *    new tabobject(...)
2952   * );
2953   * echo $OUTPUT->tabtree($rows, $selectedid);
2954   *
2955   * Multiple row tabs may not look good on some devices but if you want to use them
2956   * you can specify ->subtree for the active tabobject.
2957   *
2958   * @param array $tabrows An array of rows where each row is an array of tab objects
2959   * @param string $selected  The id of the selected tab (whatever row it's on)
2960   * @param array  $inactive  An array of ids of inactive tabs that are not selectable.
2961   * @param array  $activated An array of ids of other tabs that are currently activated
2962   * @param bool $return If true output is returned rather then echo'd
2963   * @return string HTML output if $return was set to true.
2964   */
2965  function print_tabs($tabrows, $selected = null, $inactive = null, $activated = null, $return = false) {
2966      global $OUTPUT;
2967  
2968      $tabrows = array_reverse($tabrows);
2969      $subtree = array();
2970      foreach ($tabrows as $row) {
2971          $tree = array();
2972  
2973          foreach ($row as $tab) {
2974              $tab->inactive = is_array($inactive) && in_array((string)$tab->id, $inactive);
2975              $tab->activated = is_array($activated) && in_array((string)$tab->id, $activated);
2976              $tab->selected = (string)$tab->id == $selected;
2977  
2978              if ($tab->activated || $tab->selected) {
2979                  $tab->subtree = $subtree;
2980              }
2981              $tree[] = $tab;
2982          }
2983          $subtree = $tree;
2984      }
2985      $output = $OUTPUT->tabtree($subtree);
2986      if ($return) {
2987          return $output;
2988      } else {
2989          print $output;
2990          return !empty($output);
2991      }
2992  }
2993  
2994  /**
2995   * Alter debugging level for the current request,
2996   * the change is not saved in database.
2997   *
2998   * @param int $level one of the DEBUG_* constants
2999   * @param bool $debugdisplay
3000   */
3001  function set_debugging($level, $debugdisplay = null) {
3002      global $CFG;
3003  
3004      $CFG->debug = (int)$level;
3005      $CFG->debugdeveloper = (($CFG->debug & DEBUG_DEVELOPER) === DEBUG_DEVELOPER);
3006  
3007      if ($debugdisplay !== null) {
3008          $CFG->debugdisplay = (bool)$debugdisplay;
3009      }
3010  }
3011  
3012  /**
3013   * Standard Debugging Function
3014   *
3015   * Returns true if the current site debugging settings are equal or above specified level.
3016   * If passed a parameter it will emit a debugging notice similar to trigger_error(). The
3017   * routing of notices is controlled by $CFG->debugdisplay
3018   * eg use like this:
3019   *
3020   * 1)  debugging('a normal debug notice');
3021   * 2)  debugging('something really picky', DEBUG_ALL);
3022   * 3)  debugging('annoying debug message only for developers', DEBUG_DEVELOPER);
3023   * 4)  if (debugging()) { perform extra debugging operations (do not use print or echo) }
3024   *
3025   * In code blocks controlled by debugging() (such as example 4)
3026   * any output should be routed via debugging() itself, or the lower-level
3027   * trigger_error() or error_log(). Using echo or print will break XHTML
3028   * JS and HTTP headers.
3029   *
3030   * It is also possible to define NO_DEBUG_DISPLAY which redirects the message to error_log.
3031   *
3032   * @param string $message a message to print
3033   * @param int $level the level at which this debugging statement should show
3034   * @param array $backtrace use different backtrace
3035   * @return bool
3036   */
3037  function debugging($message = '', $level = DEBUG_NORMAL, $backtrace = null) {
3038      global $CFG, $USER;
3039  
3040      $forcedebug = false;
3041      if (!empty($CFG->debugusers) && $USER) {
3042          $debugusers = explode(',', $CFG->debugusers);
3043          $forcedebug = in_array($USER->id, $debugusers);
3044      }
3045  
3046      if (!$forcedebug and (empty($CFG->debug) || ($CFG->debug != -1 and $CFG->debug < $level))) {
3047          return false;
3048      }
3049  
3050      if (!isset($CFG->debugdisplay)) {
3051          $CFG->debugdisplay = ini_get_bool('display_errors');
3052      }
3053  
3054      if ($message) {
3055          if (!$backtrace) {
3056              $backtrace = debug_backtrace();
3057          }
3058          $from = format_backtrace($backtrace, CLI_SCRIPT || NO_DEBUG_DISPLAY);
3059          if (PHPUNIT_TEST) {
3060              if (phpunit_util::debugging_triggered($message, $level, $from)) {
3061                  // We are inside test, the debug message was logged.
3062                  return true;
3063              }
3064          }
3065  
3066          if (NO_DEBUG_DISPLAY) {
3067              // Script does not want any errors or debugging in output,
3068              // we send the info to error log instead.
3069              error_log('Debugging: ' . $message . ' in '. PHP_EOL . $from);
3070  
3071          } else if ($forcedebug or $CFG->debugdisplay) {
3072              if (!defined('DEBUGGING_PRINTED')) {
3073                  define('DEBUGGING_PRINTED', 1); // Indicates we have printed something.
3074              }
3075              if (CLI_SCRIPT) {
3076                  echo "++ $message ++\n$from";
3077              } else {
3078                  echo '<div class="notifytiny debuggingmessage" data-rel="debugging">' , $message , $from , '</div>';
3079              }
3080  
3081          } else {
3082              trigger_error($message . $from, E_USER_NOTICE);
3083          }
3084      }
3085      return true;
3086  }
3087  
3088  /**
3089   * Outputs a HTML comment to the browser.
3090   *
3091   * This is used for those hard-to-debug pages that use bits from many different files in very confusing ways (e.g. blocks).
3092   *
3093   * <code>print_location_comment(__FILE__, __LINE__);</code>
3094   *
3095   * @param string $file
3096   * @param integer $line
3097   * @param boolean $return Whether to return or print the comment
3098   * @return string|void Void unless true given as third parameter
3099   */
3100  function print_location_comment($file, $line, $return = false) {
3101      if ($return) {
3102          return "<!-- $file at line $line -->\n";
3103      } else {
3104          echo "<!-- $file at line $line -->\n";
3105      }
3106  }
3107  
3108  
3109  /**
3110   * Returns true if the user is using a right-to-left language.
3111   *
3112   * @return boolean true if the current language is right-to-left (Hebrew, Arabic etc)
3113   */
3114  function right_to_left() {
3115      return (get_string('thisdirection', 'langconfig') === 'rtl');
3116  }
3117  
3118  
3119  /**
3120   * Returns swapped left<=> right if in RTL environment.
3121   *
3122   * Part of RTL Moodles support.
3123   *
3124   * @param string $align align to check
3125   * @return string
3126   */
3127  function fix_align_rtl($align) {
3128      if (!right_to_left()) {
3129          return $align;
3130      }
3131      if ($align == 'left') {
3132          return 'right';
3133      }
3134      if ($align == 'right') {
3135          return 'left';
3136      }
3137      return $align;
3138  }
3139  
3140  
3141  /**
3142   * Returns true if the page is displayed in a popup window.
3143   *
3144   * Gets the information from the URL parameter inpopup.
3145   *
3146   * @todo Use a central function to create the popup calls all over Moodle and
3147   * In the moment only works with resources and probably questions.
3148   *
3149   * @return boolean
3150   */
3151  function is_in_popup() {
3152      $inpopup = optional_param('inpopup', '', PARAM_BOOL);
3153  
3154      return ($inpopup);
3155  }
3156  
3157  /**
3158   * Progress bar class.
3159   *
3160   * Manages the display of a progress bar.
3161   *
3162   * To use this class.
3163   * - construct
3164   * - call create (or use the 3rd param to the constructor)
3165   * - call update or update_full() or update() repeatedly
3166   *
3167   * @copyright 2008 jamiesensei
3168   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3169   * @package core
3170   */
3171  class progress_bar {
3172      /** @var string html id */
3173      private $html_id;
3174      /** @var int total width */
3175      private $width;
3176      /** @var int last percentage printed */
3177      private $percent = 0;
3178      /** @var int time when last printed */
3179      private $lastupdate = 0;
3180      /** @var int when did we start printing this */
3181      private $time_start = 0;
3182  
3183      /**
3184       * Constructor
3185       *
3186       * Prints JS code if $autostart true.
3187       *
3188       * @param string $html_id
3189       * @param int $width
3190       * @param bool $autostart Default to false
3191       */
3192      public function __construct($htmlid = '', $width = 500, $autostart = false) {
3193          if (!empty($htmlid)) {
3194              $this->html_id  = $htmlid;
3195          } else {
3196              $this->html_id  = 'pbar_'.uniqid();
3197          }
3198  
3199          $this->width = $width;
3200  
3201          if ($autostart) {
3202              $this->create();
3203          }
3204      }
3205  
3206      /**
3207       * Create a new progress bar, this function will output html.
3208       *
3209       * @return void Echo's output
3210       */
3211      public function create() {
3212          global $PAGE;
3213  
3214          $this->time_start = microtime(true);
3215          if (CLI_SCRIPT) {
3216              return; // Temporary solution for cli scripts.
3217          }
3218  
3219          $PAGE->requires->string_for_js('secondsleft', 'moodle');
3220  
3221          $htmlcode = <<<EOT
3222          <div class="progressbar_container" style="width: {$this->width}px;" id="{$this->html_id}">
3223              <h2></h2>
3224              <div class="progress progress-striped active">
3225                  <div class="bar" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0">&nbsp;</div>
3226              </div>
3227              <p></p>
3228          </div>
3229  EOT;
3230          flush();
3231          echo $htmlcode;
3232          flush();
3233      }
3234  
3235      /**
3236       * Update the progress bar
3237       *
3238       * @param int $percent from 1-100
3239       * @param string $msg
3240       * @return void Echo's output
3241       * @throws coding_exception
3242       */
3243      private function _update($percent, $msg) {
3244          if (empty($this->time_start)) {
3245              throw new coding_exception('You must call create() (or use the $autostart ' .
3246                      'argument to the constructor) before you try updating the progress bar.');
3247          }
3248  
3249          if (CLI_SCRIPT) {
3250              return; // Temporary solution for cli scripts.
3251          }
3252  
3253          $estimate = $this->estimate($percent);
3254  
3255          if ($estimate === null) {
3256              // Always do the first and last updates.
3257          } else if ($estimate == 0) {
3258              // Always do the last updates.
3259          } else if ($this->lastupdate + 20 < time()) {
3260              // We must update otherwise browser would time out.
3261          } else if (round($this->percent, 2) === round($percent, 2)) {
3262              // No significant change, no need to update anything.
3263              return;
3264          }
3265          if (is_numeric($estimate)) {
3266              $estimate = get_string('secondsleft', 'moodle', round($estimate, 2));
3267          }
3268  
3269          $this->percent = round($percent, 2);
3270          $this->lastupdate = microtime(true);
3271  
3272          echo html_writer::script(js_writer::function_call('updateProgressBar',
3273              array($this->html_id, $this->percent, $msg, $estimate)));
3274          flush();
3275      }
3276  
3277      /**
3278       * Estimate how much time it is going to take.
3279       *
3280       * @param int $pt from 1-100
3281       * @return mixed Null (unknown), or int
3282       */
3283      private function estimate($pt) {
3284          if ($this->lastupdate == 0) {
3285              return null;
3286          }
3287          if ($pt < 0.00001) {
3288              return null; // We do not know yet how long it will take.
3289          }
3290          if ($pt > 99.99999) {
3291              return 0; // Nearly done, right?
3292          }
3293          $consumed = microtime(true) - $this->time_start;
3294          if ($consumed < 0.001) {
3295              return null;
3296          }
3297  
3298          return (100 - $pt) * ($consumed / $pt);
3299      }
3300  
3301      /**
3302       * Update progress bar according percent
3303       *
3304       * @param int $percent from 1-100
3305       * @param string $msg the message needed to be shown
3306       */
3307      public function update_full($percent, $msg) {
3308          $percent = max(min($percent, 100), 0);
3309          $this->_update($percent, $msg);
3310      }
3311  
3312      /**
3313       * Update progress bar according the number of tasks
3314       *
3315       * @param int $cur current task number
3316       * @param int $total total task number
3317       * @param string $msg message
3318       */
3319      public function update($cur, $total, $msg) {
3320          $percent = ($cur / $total) * 100;
3321          $this->update_full($percent, $msg);
3322      }
3323  
3324      /**
3325       * Restart the progress bar.
3326       */
3327      public function restart() {
3328          $this->percent    = 0;
3329          $this->lastupdate = 0;
3330          $this->time_start = 0;
3331      }
3332  }
3333  
3334  /**
3335   * Progress trace class.
3336   *
3337   * Use this class from long operations where you want to output occasional information about
3338   * what is going on, but don't know if, or in what format, the output should be.
3339   *
3340   * @copyright 2009 Tim Hunt
3341   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3342   * @package core
3343   */
3344  abstract class progress_trace {
3345      /**
3346       * Output an progress message in whatever format.
3347       *
3348       * @param string $message the message to output.
3349       * @param integer $depth indent depth for this message.
3350       */
3351      abstract public function output($message, $depth = 0);
3352  
3353      /**
3354       * Called when the processing is finished.
3355       */
3356      public function finished() {
3357      }
3358  }
3359  
3360  /**
3361   * This subclass of progress_trace does not ouput anything.
3362   *
3363   * @copyright 2009 Tim Hunt
3364   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3365   * @package core
3366   */
3367  class null_progress_trace extends progress_trace {
3368      /**
3369       * Does Nothing
3370       *
3371       * @param string $message
3372       * @param int $depth
3373       * @return void Does Nothing
3374       */
3375      public function output($message, $depth = 0) {
3376      }
3377  }
3378  
3379  /**
3380   * This subclass of progress_trace outputs to plain text.
3381   *
3382   * @copyright 2009 Tim Hunt
3383   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3384   * @package core
3385   */
3386  class text_progress_trace extends progress_trace {
3387      /**
3388       * Output the trace message.
3389       *
3390       * @param string $message
3391       * @param int $depth
3392       * @return void Output is echo'd
3393       */
3394      public function output($message, $depth = 0) {
3395          echo str_repeat('  ', $depth), $message, "\n";
3396          flush();
3397      }
3398  }
3399  
3400  /**
3401   * This subclass of progress_trace outputs as HTML.
3402   *
3403   * @copyright 2009 Tim Hunt
3404   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3405   * @package core
3406   */
3407  class html_progress_trace extends progress_trace {
3408      /**
3409       * Output the trace message.
3410       *
3411       * @param string $message
3412       * @param int $depth
3413       * @return void Output is echo'd
3414       */
3415      public function output($message, $depth = 0) {
3416          echo '<p>', str_repeat('&#160;&#160;', $depth), htmlspecialchars($message), "</p>\n";
3417          flush();
3418      }
3419  }
3420  
3421  /**
3422   * HTML List Progress Tree
3423   *
3424   * @copyright 2009 Tim Hunt
3425   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3426   * @package core
3427   */
3428  class html_list_progress_trace extends progress_trace {
3429      /** @var int */
3430      protected $currentdepth = -1;
3431  
3432      /**
3433       * Echo out the list
3434       *
3435       * @param string $message The message to display
3436       * @param int $depth
3437       * @return void Output is echoed
3438       */
3439      public function output($message, $depth = 0) {
3440          $samedepth = true;
3441          while ($this->currentdepth > $depth) {
3442              echo "</li>\n</ul>\n";
3443              $this->currentdepth -= 1;
3444              if ($this->currentdepth == $depth) {
3445                  echo '<li>';
3446              }
3447              $samedepth = false;
3448          }
3449          while ($this->currentdepth < $depth) {
3450              echo "<ul>\n<li>";
3451              $this->currentdepth += 1;
3452              $samedepth = false;
3453          }
3454          if ($samedepth) {
3455              echo "</li>\n<li>";
3456          }
3457          echo htmlspecialchars($message);
3458          flush();
3459      }
3460  
3461      /**
3462       * Called when the processing is finished.
3463       */
3464      public function finished() {
3465          while ($this->currentdepth >= 0) {
3466              echo "</li>\n</ul>\n";
3467              $this->currentdepth -= 1;
3468          }
3469      }
3470  }
3471  
3472  /**
3473   * This subclass of progress_trace outputs to error log.
3474   *
3475   * @copyright Petr Skoda {@link http://skodak.org}
3476   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3477   * @package core
3478   */
3479  class error_log_progress_trace extends progress_trace {
3480      /** @var string log prefix */
3481      protected $prefix;
3482  
3483      /**
3484       * Constructor.
3485       * @param string $prefix optional log prefix
3486       */
3487      public function __construct($prefix = '') {
3488          $this->prefix = $prefix;
3489      }
3490  
3491      /**
3492       * Output the trace message.
3493       *
3494       * @param string $message
3495       * @param int $depth
3496       * @return void Output is sent to error log.
3497       */
3498      public function output($message, $depth = 0) {
3499          error_log($this->prefix . str_repeat('  ', $depth) . $message);
3500      }
3501  }
3502  
3503  /**
3504   * Special type of trace that can be used for catching of output of other traces.
3505   *
3506   * @copyright Petr Skoda {@link http://skodak.org}
3507   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3508   * @package core
3509   */
3510  class progress_trace_buffer extends progress_trace {
3511      /** @var progres_trace */
3512      protected $trace;
3513      /** @var bool do we pass output out */
3514      protected $passthrough;
3515      /** @var string output buffer */
3516      protected $buffer;
3517  
3518      /**
3519       * Constructor.
3520       *
3521       * @param progress_trace $trace
3522       * @param bool $passthrough true means output and buffer, false means just buffer and no output
3523       */
3524      public function __construct(progress_trace $trace, $passthrough = true) {
3525          $this->trace       = $trace;
3526          $this->passthrough = $passthrough;
3527          $this->buffer      = '';
3528      }
3529  
3530      /**
3531       * Output the trace message.
3532       *
3533       * @param string $message the message to output.
3534       * @param int $depth indent depth for this message.
3535       * @return void output stored in buffer
3536       */
3537      public function output($message, $depth = 0) {
3538          ob_start();
3539          $this->trace->output($message, $depth);
3540          $this->buffer .= ob_get_contents();
3541          if ($this->passthrough) {
3542              ob_end_flush();
3543          } else {
3544              ob_end_clean();
3545          }
3546      }
3547  
3548      /**
3549       * Called when the processing is finished.
3550       */
3551      public function finished() {
3552          ob_start();
3553          $this->trace->finished();
3554          $this->buffer .= ob_get_contents();
3555          if ($this->passthrough) {
3556              ob_end_flush();
3557          } else {
3558              ob_end_clean();
3559          }
3560      }
3561  
3562      /**
3563       * Reset internal text buffer.
3564       */
3565      public function reset_buffer() {
3566          $this->buffer = '';
3567      }
3568  
3569      /**
3570       * Return internal text buffer.
3571       * @return string buffered plain text
3572       */
3573      public function get_buffer() {
3574          return $this->buffer;
3575      }
3576  }
3577  
3578  /**
3579   * Special type of trace that can be used for redirecting to multiple other traces.
3580   *
3581   * @copyright Petr Skoda {@link http://skodak.org}
3582   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3583   * @package core
3584   */
3585  class combined_progress_trace extends progress_trace {
3586  
3587      /**
3588       * An array of traces.
3589       * @var array
3590       */
3591      protected $traces;
3592  
3593      /**
3594       * Constructs a new instance.
3595       *
3596       * @param array $traces multiple traces
3597       */
3598      public function __construct(array $traces) {
3599          $this->traces = $traces;
3600      }
3601  
3602      /**
3603       * Output an progress message in whatever format.
3604       *
3605       * @param string $message the message to output.
3606       * @param integer $depth indent depth for this message.
3607       */
3608      public function output($message, $depth = 0) {
3609          foreach ($this->traces as $trace) {
3610              $trace->output($message, $depth);
3611          }
3612      }
3613  
3614      /**
3615       * Called when the processing is finished.
3616       */
3617      public function finished() {
3618          foreach ($this->traces as $trace) {
3619              $trace->finished();
3620          }
3621      }
3622  }
3623  
3624  /**
3625   * Returns a localized sentence in the current language summarizing the current password policy
3626   *
3627   * @todo this should be handled by a function/method in the language pack library once we have a support for it
3628   * @uses $CFG
3629   * @return string
3630   */
3631  function print_password_policy() {
3632      global $CFG;
3633  
3634      $message = '';
3635      if (!empty($CFG->passwordpolicy)) {
3636          $messages = array();
3637          $messages[] = get_string('informminpasswordlength', 'auth', $CFG->minpasswordlength);
3638          if (!empty($CFG->minpassworddigits)) {
3639              $messages[] = get_string('informminpassworddigits', 'auth', $CFG->minpassworddigits);
3640          }
3641          if (!empty($CFG->minpasswordlower)) {
3642              $messages[] = get_string('informminpasswordlower', 'auth', $CFG->minpasswordlower);
3643          }
3644          if (!empty($CFG->minpasswordupper)) {
3645              $messages[] = get_string('informminpasswordupper', 'auth', $CFG->minpasswordupper);
3646          }
3647          if (!empty($CFG->minpasswordnonalphanum)) {
3648              $messages[] = get_string('informminpasswordnonalphanum', 'auth', $CFG->minpasswordnonalphanum);
3649          }
3650  
3651          $messages = join(', ', $messages); // This is ugly but we do not have anything better yet...
3652          $message = get_string('informpasswordpolicy', 'auth', $messages);
3653      }
3654      return $message;
3655  }
3656  
3657  /**
3658   * Get the value of a help string fully prepared for display in the current language.
3659   *
3660   * @param string $identifier The identifier of the string to search for.
3661   * @param string $component The module the string is associated with.
3662   * @param boolean $ajax Whether this help is called from an AJAX script.
3663   *                This is used to influence text formatting and determines
3664   *                which format to output the doclink in.
3665   * @param string|object|array $a An object, string or number that can be used
3666   *      within translation strings
3667   * @return Object An object containing:
3668   * - heading: Any heading that there may be for this help string.
3669   * - text: The wiki-formatted help string.
3670   * - doclink: An object containing a link, the linktext, and any additional
3671   *            CSS classes to apply to that link. Only present if $ajax = false.
3672   * - completedoclink: A text representation of the doclink. Only present if $ajax = true.
3673   */
3674  function get_formatted_help_string($identifier, $component, $ajax = false, $a = null) {
3675      global $CFG, $OUTPUT;
3676      $sm = get_string_manager();
3677  
3678      // Do not rebuild caches here!
3679      // Devs need to learn to purge all caches after any change or disable $CFG->langstringcache.
3680  
3681      $data = new stdClass();
3682  
3683      if ($sm->string_exists($identifier, $component)) {
3684          $data->heading = format_string(get_string($identifier, $component));
3685      } else {
3686          // Gracefully fall back to an empty string.
3687          $data->heading = '';
3688      }
3689  
3690      if ($sm->string_exists($identifier . '_help', $component)) {
3691          $options = new stdClass();
3692          $options->trusted = false;
3693          $options->noclean = false;
3694          $options->smiley = false;
3695          $options->filter = false;
3696          $options->para = true;
3697          $options->newlines = false;
3698          $options->overflowdiv = !$ajax;
3699  
3700          // Should be simple wiki only MDL-21695.
3701          $data->text = format_text(get_string($identifier.'_help', $component, $a), FORMAT_MARKDOWN, $options);
3702  
3703          $helplink = $identifier . '_link';
3704          if ($sm->string_exists($helplink, $component)) {  // Link to further info in Moodle docs.
3705              $link = get_string($helplink, $component);
3706              $linktext = get_string('morehelp');
3707  
3708              $data->doclink = new stdClass();
3709              $url = new moodle_url(get_docs_url($link));
3710              if ($ajax) {
3711                  $data->doclink->link = $url->out();
3712                  $data->doclink->linktext = $linktext;
3713                  $data->doclink->class = ($CFG->doctonewwindow) ? 'helplinkpopup' : '';
3714              } else {
3715                  $data->completedoclink = html_writer::tag('div', $OUTPUT->doc_link($link, $linktext),
3716                      array('class' => 'helpdoclink'));
3717              }
3718          }
3719      } else {
3720          $data->text = html_writer::tag('p',
3721              html_writer::tag('strong', 'TODO') . ": missing help string [{$identifier}_help, {$component}]");
3722      }
3723      return $data;
3724  }
3725  
3726  /**
3727   * Renders a hidden password field so that browsers won't incorrectly autofill password fields with the user's password.
3728   *
3729   * @since 3.0
3730   * @return string HTML to prevent password autofill
3731   */
3732  function prevent_form_autofill_password() {
3733      return '<div class="hide"><input type="text" class="ignoredirty" /><input type="password" class="ignoredirty" /></div>';
3734  }