lib/filterlib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * Library functions for managing text filter plugins.
  20  *
  21  * @package    core
  22  * @subpackage filter
  23  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  24  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25  */
  26
  27 defined('MOODLE_INTERNAL') || die();
  28
  29 /** The states a filter can be in, stored in the filter_active table. */
  30 define('TEXTFILTER_ON', 1);
  31 /** The states a filter can be in, stored in the filter_active table. */
  32 define('TEXTFILTER_INHERIT', 0);
  33 /** The states a filter can be in, stored in the filter_active table. */
  34 define('TEXTFILTER_OFF', -1);
  35 /** The states a filter can be in, stored in the filter_active table. */
  36 define('TEXTFILTER_DISABLED', -9999);
  37
  38 /**
  39  * Define one exclusive separator that we'll use in the temp saved tags
  40  *  keys. It must be something rare enough to avoid having matches with
  41  *  filterobjects. MDL-18165
  42  */
  43 define('TEXTFILTER_EXCL_SEPARATOR', '-%-');
  44
  45
  46 /**
  47  * Class to manage the filtering of strings. It is intended that this class is
  48  * only used by weblib.php. Client code should probably be using the
  49  * format_text and format_string functions.
  50  *
  51  * This class is a singleton.
  52  *
  53  * @package    core
  54  * @subpackage filter
  55  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  56  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  57  */
  58 class filter_manager {
  59     /**
  60      * @var array This list of active filters, by context, for filtering content.
  61      * An array contextid => array of filter objects.
  62      */
  63     protected $textfilters = array();
  64
  65     /**
  66      * @var array This list of active filters, by context, for filtering strings.
  67      * An array contextid => array of filter objects.
  68      */
  69     protected $stringfilters = array();
  70
  71     /** @var array Exploded version of $CFG->stringfilters. */
  72     protected $stringfilternames = array();
  73
  74     /** @var object Holds the singleton instance. */
  75     protected static $singletoninstance;
  76
  77     protected function __construct() {
  78         $this->stringfilternames = filter_get_string_filters();
  79     }
  80
  81     /**
  82      * @return filter_manager the singleton instance.
  83      */
  84     public static function instance() {
  85         global $CFG;
  86         if (is_null(self::$singletoninstance)) {
  87             if (!empty($CFG->perfdebug)) {
  88                 self::$singletoninstance = new performance_measuring_filter_manager();
  89             } else {
  90                 self::$singletoninstance = new self();
  91             }
  92         }
  93         return self::$singletoninstance;
  94     }
  95
  96     /**
  97      * Load all the filters required by this context.
  98      *
  99      * @param object $context
 100      */
 101     protected function load_filters($context) {
 102         $filters = filter_get_active_in_context($context);
 103         $this->textfilters[$context->id] = array();
 104         $this->stringfilters[$context->id] = array();
 105         foreach ($filters as $filtername => $localconfig) {
 106             $filter = $this->make_filter_object($filtername, $context, $localconfig);
 107             if (is_null($filter)) {
 108                 continue;
 109             }
 110             $this->textfilters[$context->id][] = $filter;
 111             if (in_array($filtername, $this->stringfilternames)) {
 112                 $this->stringfilters[$context->id][] = $filter;
 113             }
 114         }
 115     }
 116
 117     /**
 118      * Factory method for creating a filter
 119      *
 120      * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 121      * @param object $context context object.
 122      * @param array $localconfig array of local configuration variables for this filter.
 123      * @return object moodle_text_filter The filter, or null, if this type of filter is
 124      *      not recognised or could not be created.
 125      */
 126     protected function make_filter_object($filtername, $context, $localconfig) {
 127         global $CFG;
 128         $path = $CFG->dirroot .'/'. $filtername .'/filter.php';
 129         if (!is_readable($path)) {
 130             return null;
 131         }
 132         include_once($path);
 133
 134         $filterclassname = 'filter_' . basename($filtername);
 135         if (class_exists($filterclassname)) {
 136             return new $filterclassname($context, $localconfig);
 137         }
 138
 139         // TODO: deprecated since 2.2, will be out in 2.3, see MDL-29996
 140         $legacyfunctionname = basename($filtername) . '_filter';
 141         if (function_exists($legacyfunctionname)) {
 142             return new legacy_filter($legacyfunctionname, $context, $localconfig);
 143         }
 144
 145         return null;
 146     }
 147
 148     /**
 149      * @todo Document this function
 150      * @param string $text
 151      * @param array $filterchain
 152      * @param array $options options passed to the filters
 153      * @return string $text
 154      */
 155     protected function apply_filter_chain($text, $filterchain, array $options = array()) {
 156         foreach ($filterchain as $filter) {
 157             $text = $filter->filter($text, $options);
 158         }
 159         return $text;
 160     }
 161
 162     /**
 163      * @todo Document this function
 164      * @param object $context
 165      * @return object A text filter
 166      */
 167     protected function get_text_filters($context) {
 168         if (!isset($this->textfilters[$context->id])) {
 169             $this->load_filters($context);
 170         }
 171         return $this->textfilters[$context->id];
 172     }
 173
 174     /**
 175      * @todo Document this function
 176      * @param object $context
 177      * @return object A string filter
 178      */
 179     protected function get_string_filters($context) {
 180         if (!isset($this->stringfilters[$context->id])) {
 181             $this->load_filters($context);
 182         }
 183         return $this->stringfilters[$context->id];
 184     }
 185
 186     /**
 187      * Filter some text
 188      *
 189      * @param string $text The text to filter
 190      * @param object $context
 191      * @param array $options options passed to the filters
 192      * @return string resulting text
 193      */
 194     public function filter_text($text, $context, array $options = array()) {
 195         $text = $this->apply_filter_chain($text, $this->get_text_filters($context), $options);
 196         /// <nolink> tags removed for XHTML compatibility
 197         $text = str_replace(array('<nolink>', '</nolink>'), '', $text);
 198         return $text;
 199     }
 200
 201     /**
 202      * Filter a piece of string
 203      *
 204      * @param string $string The text to filter
 205      * @param object $context
 206      * @return string resulting string
 207      */
 208     public function filter_string($string, $context) {
 209         return $this->apply_filter_chain($string, $this->get_string_filters($context));
 210     }
 211
 212     /**
 213      * @todo Document this function
 214      * @param object $context
 215      * @return object A string filter
 216      */
 217     public function text_filtering_hash($context) {
 218         $filters = $this->get_text_filters($context);
 219         $hashes = array();
 220         foreach ($filters as $filter) {
 221             $hashes[] = $filter->hash();
 222         }
 223         return implode('-', $hashes);
 224     }
 225 }
 226
 227 /**
 228  * Filter manager subclass that does nothing. Having this simplifies the logic
 229  * of format_text, etc.
 230  *
 231  * @todo Document this class
 232  *
 233  * @package    core
 234  * @subpackage filter
 235  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
 236  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 237  */
 238 class null_filter_manager {
 239     /**
 240      * @return string
 241      */
 242     public function filter_text($text, $context, $options) {
 243         return $text;
 244     }
 245
 246     /**
 247      * @return string
 248      */
 249     public function filter_string($string, $context) {
 250         return $string;
 251     }
 252
 253     /**
 254      * @return string
 255      */
 256     public function text_filtering_hash() {
 257         return '';
 258     }
 259 }
 260
 261 /**
 262  * Filter manager subclass that tacks how much work it does.
 263  *
 264  * @todo Document this class
 265  *
 266  * @package    core
 267  * @subpackage filter
 268  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
 269  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 270  */
 271 class performance_measuring_filter_manager extends filter_manager {
 272     /** @var int */
 273     protected $filterscreated = 0;
 274     protected $textsfiltered = 0;
 275     protected $stringsfiltered = 0;
 276
 277     /**
 278      * @param string $filtername
 279      * @param object $context
 280      * @param mixed $localconfig
 281      * @return mixed
 282      */
 283     protected function make_filter_object($filtername, $context, $localconfig) {
 284         $this->filterscreated++;
 285         return parent::make_filter_object($filtername, $context, $localconfig);
 286     }
 287
 288     /**
 289      * @param string $text
 290      * @param object $context
 291      * @param array $options options passed to the filters
 292      * @return mixed
 293      */
 294     public function filter_text($text, $context, array $options = array()) {
 295         $this->textsfiltered++;
 296         return parent::filter_text($text, $context, $options);
 297     }
 298
 299     /**
 300      * @param string $string
 301      * @param object $context
 302      * @return mixed
 303      */
 304     public function filter_string($string, $context) {
 305         $this->stringsfiltered++;
 306         return parent::filter_string($string, $context);
 307     }
 308
 309     /**
 310      * @return array
 311      */
 312     public function get_performance_summary() {
 313         return array(array(
 314             'contextswithfilters' => count($this->textfilters),
 315             'filterscreated' => $this->filterscreated,
 316             'textsfiltered' => $this->textsfiltered,
 317             'stringsfiltered' => $this->stringsfiltered,
 318         ), array(
 319             'contextswithfilters' => 'Contexts for which filters were loaded',
 320             'filterscreated' => 'Filters created',
 321             'textsfiltered' => 'Pieces of content filtered',
 322             'stringsfiltered' => 'Strings filtered',
 323         ));
 324     }
 325 }
 326
 327 /**
 328  * Base class for text filters. You just need to override this class and
 329  * implement the filter method.
 330  *
 331  * @package    core
 332  * @subpackage filter
 333  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
 334  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 335  */
 336 abstract class moodle_text_filter {
 337     /** @var object The context we are in. */
 338     protected $context;
 339     /** @var array Any local configuration for this filter in this context. */
 340     protected $localconfig;
 341
 342     /**
 343      * Set any context-specific configuration for this filter.
 344      * @param object $context The current course id.
 345      * @param object $context The current context.
 346      * @param array $config Any context-specific configuration for this filter.
 347      */
 348     public function __construct($context, array $localconfig) {
 349         $this->context = $context;
 350         $this->localconfig = $localconfig;
 351     }
 352
 353     /**
 354      * @return string The class name of the current class
 355      */
 356     public function hash() {
 357         return __CLASS__;
 358     }
 359
 360     /**
 361      * Override this function to actually implement the filtering.
 362      *
 363      * @param $text some HTML content.
 364      * @param array $options options passed to the filters
 365      * @return the HTML content after the filtering has been applied.
 366      */
 367     public abstract function filter($text, array $options = array());
 368 }
 369
 370 /**
 371  * moodle_text_filter implementation that encapsulates an old-style filter that
 372  * only defines a function, not a class.
 373  *
 374  * @deprecated since 2.2, see MDL-29995
 375  * @todo will be out in 2.3, see MDL-29996
 376  * @package    core
 377  * @subpackage filter
 378  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
 379  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 380  */
 381 class legacy_filter extends moodle_text_filter {
 382     /** @var string */
 383     protected $filterfunction;
 384     protected $courseid;
 385
 386     /**
 387      * Set any context-specific configuration for this filter.
 388      *
 389      * @param string $filterfunction
 390      * @param object $context The current context.
 391      * @param array $config Any context-specific configuration for this filter.
 392      */
 393     public function __construct($filterfunction, $context, array $localconfig) {
 394         parent::__construct($context, $localconfig);
 395         $this->filterfunction = $filterfunction;
 396         $this->courseid = get_courseid_from_context($this->context);
 397     }
 398
 399     /**
 400      * @param string $text
 401      * @param array $options options - not supported for legacy filters
 402      * @return mixed
 403      */
 404     public function filter($text, array $options = array()) {
 405         if ($this->courseid) {
 406             // old filters are called only when inside courses
 407             return call_user_func($this->filterfunction, $this->courseid, $text);
 408         } else {
 409             return $text;
 410         }
 411     }
 412 }
 413
 414 /**
 415  * This is just a little object to define a phrase and some instructions
 416  * for how to process it.  Filters can create an array of these to pass
 417  * to the filter_phrases function below.
 418  *
 419  * @package    core
 420  * @subpackage filter
 421  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
 422  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 423  **/
 424 class filterobject {
 425     /** @var string */
 426     var $phrase;
 427     var $hreftagbegin;
 428     var $hreftagend;
 429     /** @var bool */
 430     var $casesensitive;
 431     var $fullmatch;
 432     /** @var mixed */
 433     var $replacementphrase;
 434     var $work_phrase;
 435     var $work_hreftagbegin;
 436     var $work_hreftagend;
 437     var $work_casesensitive;
 438     var $work_fullmatch;
 439     var $work_replacementphrase;
 440     /** @var bool */
 441     var $work_calculated;
 442
 443     /**
 444      * A constructor just because I like constructing
 445      *
 446      * @param string $phrase
 447      * @param string $hreftagbegin
 448      * @param string $hreftagend
 449      * @param bool $casesensitive
 450      * @param bool $fullmatch
 451      * @param mixed $replacementphrase
 452      */
 453     function filterobject($phrase, $hreftagbegin = '<span class="highlight">',
 454                                    $hreftagend = '</span>',
 455                                    $casesensitive = false,
 456                                    $fullmatch = false,
 457                                    $replacementphrase = NULL) {
 458
 459         $this->phrase           = $phrase;
 460         $this->hreftagbegin     = $hreftagbegin;
 461         $this->hreftagend       = $hreftagend;
 462         $this->casesensitive    = $casesensitive;
 463         $this->fullmatch        = $fullmatch;
 464         $this->replacementphrase= $replacementphrase;
 465         $this->work_calculated  = false;
 466
 467     }
 468 }
 469
 470 /**
 471  * Look up the name of this filter in the most appropriate location.
 472  * If $filterlocation = 'mod' then does get_string('filtername', $filter);
 473  * else if $filterlocation = 'filter' then does get_string('filtername', 'filter_' . $filter);
 474  * with a fallback to get_string('filtername', $filter) for backwards compatibility.
 475  * These are the only two options supported at the moment.
 476  *
 477  * @param string $filter the folder name where the filter lives.
 478  * @return string the human-readable name for this filter.
 479  */
 480 function filter_get_name($filter) {
 481     // TODO: should we be using pluginname here instead? , see MDL-29998
 482     list($type, $filter) = explode('/', $filter);
 483     switch ($type) {
 484         case 'filter':
 485             $strfiltername = get_string('filtername', 'filter_' . $filter);
 486             if (substr($strfiltername, 0, 2) != '[[') {
 487                 // found a valid string.
 488                 return $strfiltername;
 489             }
 490             // Fall through to try the legacy location.
 491
 492         // TODO: deprecated since 2.2, will be out in 2.3, see MDL-29996
 493         case 'mod':
 494             $strfiltername = get_string('filtername', $filter);
 495             if (substr($strfiltername, 0, 2) == '[[') {
 496                 $strfiltername .= ' (' . $type . '/' . $filter . ')';
 497             }
 498             return $strfiltername;
 499
 500         default:
 501             throw new coding_exception('Unknown filter type ' . $type);
 502     }
 503 }
 504
 505 /**
 506  * Get the names of all the filters installed in this Moodle.
 507  *
 508  * @global object
 509  * @return array path => filter name from the appropriate lang file. e.g.
 510  * array('mod/glossary' => 'Glossary Auto-linking', 'filter/tex' => 'TeX Notation');
 511  * sorted in alphabetical order of name.
 512  */
 513 function filter_get_all_installed() {
 514     global $CFG;
 515     $filternames = array();
 516     // TODO: deprecated since 2.2, will be out in 2.3, see MDL-29996
 517     $filterlocations = array('mod', 'filter');
 518     foreach ($filterlocations as $filterlocation) {
 519         // TODO: move get_list_of_plugins() to get_plugin_list()
 520         $filters = get_list_of_plugins($filterlocation);
 521         foreach ($filters as $filter) {
 522             // MDL-29994 - Ignore mod/data and mod/glossary filters forever, this will be out in 2.3
 523             if ($filterlocation == 'mod' && ($filter == 'data' || $filter == 'glossary')) {
 524                 continue;
 525             }
 526             $path = $filterlocation . '/' . $filter;
 527             if (is_readable($CFG->dirroot . '/' . $path . '/filter.php')) {
 528                 $strfiltername = filter_get_name($path);
 529                 $filternames[$path] = $strfiltername;
 530             }
 531         }
 532     }
 533     collatorlib::asort($filternames);
 534     return $filternames;
 535 }
 536
 537 /**
 538  * Set the global activated state for a text filter.
 539  *
 540  * @global object
 541  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 542  * @param integer $state One of the values TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_DISABLED.
 543  * @param integer $sortorder (optional) a position in the sortorder to place this filter.
 544  *      If not given defaults to:
 545  *      No change in order if we are updating an existing record, and not changing to or from TEXTFILTER_DISABLED.
 546  *      Just after the last currently active filter when adding an unknown filter
 547  *          in state TEXTFILTER_ON or TEXTFILTER_OFF, or enabling/disabling an existing filter.
 548  *      Just after the very last filter when adding an unknown filter in state TEXTFILTER_DISABLED
 549  */
 550 function filter_set_global_state($filter, $state, $sortorder = false) {
 551     global $DB;
 552
 553     // Check requested state is valid.
 554     if (!in_array($state, array(TEXTFILTER_ON, TEXTFILTER_OFF, TEXTFILTER_DISABLED))) {
 555         throw new coding_exception("Illegal option '$state' passed to filter_set_global_state. " .
 556                 "Must be one of TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_DISABLED.");
 557     }
 558
 559     // Check sortorder is valid.
 560     if ($sortorder !== false) {
 561         if ($sortorder < 1 || $sortorder > $DB->get_field('filter_active', 'MAX(sortorder)', array()) + 1) {
 562             throw new coding_exception("Invalid sort order passed to filter_set_global_state.");
 563         }
 564     }
 565
 566     // See if there is an existing record.
 567     $syscontext = get_context_instance(CONTEXT_SYSTEM);
 568     $rec = $DB->get_record('filter_active', array('filter' => $filter, 'contextid' => $syscontext->id));
 569     if (empty($rec)) {
 570         $insert = true;
 571         $rec = new stdClass;
 572         $rec->filter = $filter;
 573         $rec->contextid = $syscontext->id;
 574     } else {
 575         $insert = false;
 576         if ($sortorder === false && !($rec->active == TEXTFILTER_DISABLED xor $state == TEXTFILTER_DISABLED)) {
 577             $sortorder = $rec->sortorder;
 578         }
 579     }
 580
 581     // Automatic sort order.
 582     if ($sortorder === false) {
 583         if ($state == TEXTFILTER_DISABLED && $insert) {
 584             $prevmaxsortorder = $DB->get_field('filter_active', 'MAX(sortorder)', array());
 585         } else {
 586             $prevmaxsortorder = $DB->get_field_select('filter_active', 'MAX(sortorder)', 'active <> ?', array(TEXTFILTER_DISABLED));
 587         }
 588         if (empty($prevmaxsortorder)) {
 589             $sortorder = 1;
 590         } else {
 591             $sortorder = $prevmaxsortorder + 1;
 592             if (!$insert && $state == TEXTFILTER_DISABLED) {
 593                 $sortorder = $prevmaxsortorder;
 594             }
 595         }
 596     }
 597
 598     // Move any existing records out of the way of the sortorder.
 599     if ($insert) {
 600         $DB->execute('UPDATE {filter_active} SET sortorder = sortorder + 1 WHERE sortorder >= ?', array($sortorder));
 601     } else if ($sortorder != $rec->sortorder) {
 602         $sparesortorder = $DB->get_field('filter_active', 'MIN(sortorder)', array()) - 1;
 603         $DB->set_field('filter_active', 'sortorder', $sparesortorder, array('filter' => $filter, 'contextid' => $syscontext->id));
 604         if ($sortorder < $rec->sortorder) {
 605             $DB->execute('UPDATE {filter_active} SET sortorder = sortorder + 1 WHERE sortorder >= ? AND sortorder < ?',
 606                     array($sortorder, $rec->sortorder));
 607         } else if ($sortorder > $rec->sortorder) {
 608             $DB->execute('UPDATE {filter_active} SET sortorder = sortorder - 1 WHERE sortorder <= ? AND sortorder > ?',
 609                     array($sortorder, $rec->sortorder));
 610         }
 611     }
 612
 613     // Insert/update the new record.
 614     $rec->active = $state;
 615     $rec->sortorder = $sortorder;
 616     if ($insert) {
 617         $DB->insert_record('filter_active', $rec);
 618     } else {
 619         $DB->update_record('filter_active', $rec);
 620     }
 621 }
 622
 623 /**
 624  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 625  * @return boolean is this filter allowed to be used on this site. That is, the
 626  *      admin has set the global 'active' setting to On, or Off, but available.
 627  */
 628 function filter_is_enabled($filter) {
 629     return array_key_exists($filter, filter_get_globally_enabled());
 630 }
 631
 632 /**
 633  * Return a list of all the filters that may be in use somewhere.
 634  *
 635  * @staticvar array $enabledfilters
 636  * @return array where the keys and values are both the filter name, like 'filter/tex'.
 637  */
 638 function filter_get_globally_enabled() {
 639     static $enabledfilters = null;
 640     if (is_null($enabledfilters)) {
 641         $filters = filter_get_global_states();
 642         $enabledfilters = array();
 643         foreach ($filters as $filter => $filerinfo) {
 644             if ($filerinfo->active != TEXTFILTER_DISABLED) {
 645                 $enabledfilters[$filter] = $filter;
 646             }
 647         }
 648     }
 649     return $enabledfilters;
 650 }
 651
 652 /**
 653  * Return the names of the filters that should also be applied to strings
 654  * (when they are enabled).
 655  *
 656  * @global object
 657  * @return array where the keys and values are both the filter name, like 'filter/tex'.
 658  */
 659 function filter_get_string_filters() {
 660     global $CFG;
 661     $stringfilters = array();
 662     if (!empty($CFG->filterall) && !empty($CFG->stringfilters)) {
 663         $stringfilters = explode(',', $CFG->stringfilters);
 664         $stringfilters = array_combine($stringfilters, $stringfilters);
 665     }
 666     return $stringfilters;
 667 }
 668
 669 /**
 670  * Sets whether a particular active filter should be applied to all strings by
 671  * format_string, or just used by format_text.
 672  *
 673  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 674  * @param boolean $applytostrings if true, this filter will apply to format_string
 675  *      and format_text, when it is enabled.
 676  */
 677 function filter_set_applies_to_strings($filter, $applytostrings) {
 678     $stringfilters = filter_get_string_filters();
 679     $numstringfilters = count($stringfilters);
 680     if ($applytostrings) {
 681         $stringfilters[$filter] = $filter;
 682     } else {
 683         unset($stringfilters[$filter]);
 684     }
 685     if (count($stringfilters) != $numstringfilters) {
 686         set_config('stringfilters', implode(',', $stringfilters));
 687         set_config('filterall', !empty($stringfilters));
 688     }
 689 }
 690
 691 /**
 692  * Set the local activated state for a text filter.
 693  *
 694  * @global object
 695  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 696  * @param integer $contextid The id of the context to get the local config for.
 697  * @param integer $state One of the values TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_INHERIT.
 698  * @return void
 699  */
 700 function filter_set_local_state($filter, $contextid, $state) {
 701     global $DB;
 702
 703     // Check requested state is valid.
 704     if (!in_array($state, array(TEXTFILTER_ON, TEXTFILTER_OFF, TEXTFILTER_INHERIT))) {
 705         throw new coding_exception("Illegal option '$state' passed to filter_set_local_state. " .
 706                 "Must be one of TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_INHERIT.");
 707     }
 708
 709     if ($contextid == get_context_instance(CONTEXT_SYSTEM)->id) {
 710         throw new coding_exception('You cannot use filter_set_local_state ' .
 711                 'with $contextid equal to the system context id.');
 712     }
 713
 714     if ($state == TEXTFILTER_INHERIT) {
 715         $DB->delete_records('filter_active', array('filter' => $filter, 'contextid' => $contextid));
 716         return;
 717     }
 718
 719     $rec = $DB->get_record('filter_active', array('filter' => $filter, 'contextid' => $contextid));
 720     $insert = false;
 721     if (empty($rec)) {
 722         $insert = true;
 723         $rec = new stdClass;
 724         $rec->filter = $filter;
 725         $rec->contextid = $contextid;
 726     }
 727
 728     $rec->active = $state;
 729
 730     if ($insert) {
 731         $DB->insert_record('filter_active', $rec);
 732     } else {
 733         $DB->update_record('filter_active', $rec);
 734     }
 735 }
 736
 737 /**
 738  * Set a particular local config variable for a filter in a context.
 739  *
 740  * @global object
 741  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 742  * @param integer $contextid The id of the context to get the local config for.
 743  * @param string $name the setting name.
 744  * @param string $value the corresponding value.
 745  */
 746 function filter_set_local_config($filter, $contextid, $name, $value) {
 747     global $DB;
 748     $rec = $DB->get_record('filter_config', array('filter' => $filter, 'contextid' => $contextid, 'name' => $name));
 749     $insert = false;
 750     if (empty($rec)) {
 751         $insert = true;
 752         $rec = new stdClass;
 753         $rec->filter = $filter;
 754         $rec->contextid = $contextid;
 755         $rec->name = $name;
 756     }
 757
 758     $rec->value = $value;
 759
 760     if ($insert) {
 761         $DB->insert_record('filter_config', $rec);
 762     } else {
 763         $DB->update_record('filter_config', $rec);
 764     }
 765 }
 766
 767 /**
 768  * Remove a particular local config variable for a filter in a context.
 769  *
 770  * @global object
 771  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 772  * @param integer $contextid The id of the context to get the local config for.
 773  * @param string $name the setting name.
 774  */
 775 function filter_unset_local_config($filter, $contextid, $name) {
 776     global $DB;
 777     $DB->delete_records('filter_config', array('filter' => $filter, 'contextid' => $contextid, 'name' => $name));
 778 }
 779
 780 /**
 781  * Get local config variables for a filter in a context. Normally (when your
 782  * filter is running) you don't need to call this, becuase the config is fetched
 783  * for you automatically. You only need this, for example, when you are getting
 784  * the config so you can show the user an editing from.
 785  *
 786  * @global object
 787  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
 788  * @param integer $contextid The ID of the context to get the local config for.
 789  * @return array of name => value pairs.
 790  */
 791 function filter_get_local_config($filter, $contextid) {
 792     global $DB;
 793     return $DB->get_records_menu('filter_config', array('filter' => $filter, 'contextid' => $contextid), '', 'name,value');
 794 }
 795
 796 /**
 797  * This function is for use by backup. Gets all the filter information specific
 798  * to one context.
 799  *
 800  * @global object
 801  * @param int $contextid
 802  * @return array Array with two elements. The first element is an array of objects with
 803  *      fields filter and active. These come from the filter_active table. The
 804  *      second element is an array of objects with fields filter, name and value
 805  *      from the filter_config table.
 806  */
 807 function filter_get_all_local_settings($contextid) {
 808     global $DB;
 809     $context = get_context_instance(CONTEXT_SYSTEM);
 810     return array(
 811         $DB->get_records('filter_active', array('contextid' => $contextid), 'filter', 'filter,active'),
 812         $DB->get_records('filter_config', array('contextid' => $contextid), 'filter,name', 'filter,name,value'),
 813     );
 814 }
 815
 816 /**
 817  * Get the list of active filters, in the order that they should be used
 818  * for a particular context, along with any local configuration variables.
 819  *
 820  * @global object
 821  * @param object $context a context
 822  * @return array an array where the keys are the filter names, for example
 823  *      'filter/tex' or 'mod/glossary' and the values are any local
 824  *      configuration for that filter, as an array of name => value pairs
 825  *      from the filter_config table. In a lot of cases, this will be an
 826  *      empty array. So, an example return value for this function might be
 827  *      array('filter/tex' => array(), 'mod/glossary' => array('glossaryid', 123))
 828  */
 829 function filter_get_active_in_context($context) {
 830     global $DB, $FILTERLIB_PRIVATE;
 831
 832     if (!isset($FILTERLIB_PRIVATE)) {
 833         $FILTERLIB_PRIVATE = new stdClass();
 834     }
 835
 836     // Use cache (this is a within-request cache only) if available. See
 837     // function filter_preload_activities.
 838     if (isset($FILTERLIB_PRIVATE->active) &&
 839             array_key_exists($context->id, $FILTERLIB_PRIVATE->active)) {
 840         return $FILTERLIB_PRIVATE->active[$context->id];
 841     }
 842
 843     $contextids = str_replace('/', ',', trim($context->path, '/'));
 844
 845     // The following SQL is tricky. It is explained on
 846     // http://docs.moodle.org/dev/Filter_enable/disable_by_context
 847     $sql = "SELECT active.filter, fc.name, fc.value
 848          FROM (SELECT f.filter, MAX(f.sortorder) AS sortorder
 849              FROM {filter_active} f
 850              JOIN {context} ctx ON f.contextid = ctx.id
 851              WHERE ctx.id IN ($contextids)
 852              GROUP BY filter
 853              HAVING MAX(f.active * " . $DB->sql_cast_2signed('ctx.depth') .
 854                     ") > -MIN(f.active * " . $DB->sql_cast_2signed('ctx.depth') . ")
 855          ) active
 856          LEFT JOIN {filter_config} fc ON fc.filter = active.filter AND fc.contextid = $context->id
 857          ORDER BY active.sortorder";
 858     //TODO: remove sql_cast_2signed() once we do not support upgrade from Moodle 2.2
 859     $rs = $DB->get_recordset_sql($sql);
 860
 861     // Masssage the data into the specified format to return.
 862     $filters = array();
 863     foreach ($rs as $row) {
 864         if (!isset($filters[$row->filter])) {
 865             $filters[$row->filter] = array();
 866         }
 867         if (!is_null($row->name)) {
 868             $filters[$row->filter][$row->name] = $row->value;
 869         }
 870     }
 871
 872     $rs->close();
 873
 874     return $filters;
 875 }
 876
 877 /**
 878  * Preloads the list of active filters for all activities (modules) on the course
 879  * using two database queries.
 880  * @param course_modinfo $modinfo Course object from get_fast_modinfo
 881  */
 882 function filter_preload_activities(course_modinfo $modinfo) {
 883     global $DB, $FILTERLIB_PRIVATE;
 884
 885     if (!isset($FILTERLIB_PRIVATE)) {
 886         $FILTERLIB_PRIVATE = new stdClass();
 887     }
 888
 889     // Don't repeat preload
 890     if (!isset($FILTERLIB_PRIVATE->preloaded)) {
 891         $FILTERLIB_PRIVATE->preloaded = array();
 892     }
 893     if (!empty($FILTERLIB_PRIVATE->preloaded[$modinfo->get_course_id()])) {
 894         return;
 895     }
 896     $FILTERLIB_PRIVATE->preloaded[$modinfo->get_course_id()] = true;
 897
 898     // Get contexts for all CMs
 899     $cmcontexts = array();
 900     $cmcontextids = array();
 901     foreach ($modinfo->get_cms() as $cm) {
 902         $modulecontext = get_context_instance(CONTEXT_MODULE, $cm->id);
 903         $cmcontextids[] = $modulecontext->id;
 904         $cmcontexts[] = $modulecontext;
 905     }
 906
 907     // Get course context and all other parents...
 908     $coursecontext = get_context_instance(CONTEXT_COURSE, $modinfo->get_course_id());
 909     $parentcontextids = explode('/', substr($coursecontext->path, 1));
 910     $allcontextids = array_merge($cmcontextids, $parentcontextids);
 911
 912     // Get all filter_active rows relating to all these contexts
 913     list ($sql, $params) = $DB->get_in_or_equal($allcontextids);
 914     $filteractives = $DB->get_records_select('filter_active', "contextid $sql", $params);
 915
 916     // Get all filter_config only for the cm contexts
 917     list ($sql, $params) = $DB->get_in_or_equal($cmcontextids);
 918     $filterconfigs = $DB->get_records_select('filter_config', "contextid $sql", $params);
 919
 920     // Note: I was a bit surprised that filter_config only works for the
 921     // most specific context (i.e. it does not need to be checked for course
 922     // context if we only care about CMs) however basede on code in
 923     // filter_get_active_in_context, this does seem to be correct.
 924
 925     // Build course default active list. Initially this will be an array of
 926     // filter name => active score (where an active score >0 means it's active)
 927     $courseactive = array();
 928
 929     // Also build list of filter_active rows below course level, by contextid
 930     $remainingactives = array();
 931
 932     // Array lists filters that are banned at top level
 933     $banned = array();
 934
 935     // Add any active filters in parent contexts to the array
 936     foreach ($filteractives as $row) {
 937         $depth = array_search($row->contextid, $parentcontextids);
 938         if ($depth !== false) {
 939             // Find entry
 940             if (!array_key_exists($row->filter, $courseactive)) {
 941                 $courseactive[$row->filter] = 0;
 942             }
 943             // This maths copes with reading rows in any order. Turning on/off
 944             // at site level counts 1, at next level down 4, at next level 9,
 945             // then 16, etc. This means the deepest level always wins, except
 946             // against the -9999 at top level.
 947             $courseactive[$row->filter] +=
 948                 ($depth + 1) * ($depth + 1) * $row->active;
 949
 950             if ($row->active == TEXTFILTER_DISABLED) {
 951                 $banned[$row->filter] = true;
 952             }
 953         } else {
 954             // Build list of other rows indexed by contextid
 955             if (!array_key_exists($row->contextid, $remainingactives)) {
 956                 $remainingactives[$row->contextid] = array();
 957             }
 958             $remainingactives[$row->contextid][] = $row;
 959         }
 960     }
 961
 962     // Chuck away the ones that aren't active
 963     foreach ($courseactive as $filter=>$score) {
 964         if ($score <= 0) {
 965             unset($courseactive[$filter]);
 966         } else {
 967             $courseactive[$filter] = array();
 968         }
 969     }
 970
 971     // Loop through the contexts to reconstruct filter_active lists for each
 972     // cm on the course
 973     if (!isset($FILTERLIB_PRIVATE->active)) {
 974         $FILTERLIB_PRIVATE->active = array();
 975     }
 976     foreach ($cmcontextids as $contextid) {
 977         // Copy course list
 978         $FILTERLIB_PRIVATE->active[$contextid] = $courseactive;
 979
 980         // Are there any changes to the active list?
 981         if (array_key_exists($contextid, $remainingactives)) {
 982             foreach ($remainingactives[$contextid] as $row) {
 983                 if ($row->active > 0 && empty($banned[$row->filter])) {
 984                     // If it's marked active for specific context, add entry
 985                     // (doesn't matter if one exists already)
 986                     $FILTERLIB_PRIVATE->active[$contextid][$row->filter] = array();
 987                 } else {
 988                     // If it's marked inactive, remove entry (doesn't matter
 989                     // if it doesn't exist)
 990                     unset($FILTERLIB_PRIVATE->active[$contextid][$row->filter]);
 991                 }
 992             }
 993         }
 994     }
 995
 996     // Process all config rows to add config data to these entries
 997     foreach ($filterconfigs as $row) {
 998         if (isset($FILTERLIB_PRIVATE->active[$row->contextid][$row->filter])) {
 999             $FILTERLIB_PRIVATE->active[$row->contextid][$row->filter][$row->name] = $row->value;
1000         }
1001     }
1002 }
1003
1004 /**
1005  * List all of the filters that are available in this context, and what the
1006  * local and inherited states of that filter are.
1007  *
1008  * @global object
1009  * @param object $context a context that is not the system context.
1010  * @return array an array with filter names, for example 'filter/tex' or
1011  *      'mod/glossary' as keys. and and the values are objects with fields:
1012  *      ->filter filter name, same as the key.
1013  *      ->localstate TEXTFILTER_ON/OFF/INHERIT
1014  *      ->inheritedstate TEXTFILTER_ON/OFF - the state that will be used if localstate is set to TEXTFILTER_INHERIT.
1015  */
1016 function filter_get_available_in_context($context) {
1017     global $DB;
1018
1019     // The complex logic is working out the active state in the parent context,
1020     // so strip the current context from the list.
1021     $contextids = explode('/', trim($context->path, '/'));
1022     array_pop($contextids);
1023     $contextids = implode(',', $contextids);
1024     if (empty($contextids)) {
1025         throw new coding_exception('filter_get_available_in_context cannot be called with the system context.');
1026     }
1027
1028     // The following SQL is tricky, in the same way at the SQL in filter_get_active_in_context.
1029     $sql = "SELECT parent_states.filter,
1030                 CASE WHEN fa.active IS NULL THEN " . TEXTFILTER_INHERIT . "
1031                 ELSE fa.active END AS localstate,
1032              parent_states.inheritedstate
1033          FROM (SELECT f.filter, MAX(f.sortorder) AS sortorder,
1034                     CASE WHEN MAX(f.active * " . $DB->sql_cast_2signed('ctx.depth') .
1035                             ") > -MIN(f.active * " . $DB->sql_cast_2signed('ctx.depth') . ") THEN " . TEXTFILTER_ON . "
1036                     ELSE " . TEXTFILTER_OFF . " END AS inheritedstate
1037              FROM {filter_active} f
1038              JOIN {context} ctx ON f.contextid = ctx.id
1039              WHERE ctx.id IN ($contextids)
1040              GROUP BY f.filter
1041              HAVING MIN(f.active) > " . TEXTFILTER_DISABLED . "
1042          ) parent_states
1043          LEFT JOIN {filter_active} fa ON fa.filter = parent_states.filter AND fa.contextid = $context->id
1044          ORDER BY parent_states.sortorder";
1045     return $DB->get_records_sql($sql);
1046 }
1047
1048 /**
1049  * This function is for use by the filter administration page.
1050  *
1051  * @global object
1052  * @return array 'filtername' => object with fields 'filter' (=filtername), 'active' and 'sortorder'
1053  */
1054 function filter_get_global_states() {
1055     global $DB;
1056     $context = get_context_instance(CONTEXT_SYSTEM);
1057     return $DB->get_records('filter_active', array('contextid' => $context->id), 'sortorder', 'filter,active,sortorder');
1058 }
1059
1060 /**
1061  * Delete all the data in the database relating to a filter, prior to deleting it.
1062  *
1063  * @global object
1064  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
1065  */
1066 function filter_delete_all_for_filter($filter) {
1067     global $DB;
1068     if (substr($filter, 0, 7) == 'filter/') {
1069         unset_all_config_for_plugin('filter_' . basename($filter));
1070     }
1071     $DB->delete_records('filter_active', array('filter' => $filter));
1072     $DB->delete_records('filter_config', array('filter' => $filter));
1073 }
1074
1075 /**
1076  * Delete all the data in the database relating to a context, used when contexts are deleted.
1077  *
1078  * @param integer $contextid The id of the context being deleted.
1079  */
1080 function filter_delete_all_for_context($contextid) {
1081     global $DB;
1082     $DB->delete_records('filter_active', array('contextid' => $contextid));
1083     $DB->delete_records('filter_config', array('contextid' => $contextid));
1084 }
1085
1086 /**
1087  * Does this filter have a global settings page in the admin tree?
1088  * (The settings page for a filter must be called, for example,
1089  * filtersettingfiltertex or filtersettingmodglossay.)
1090  *
1091  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
1092  * @return boolean Whether there should be a 'Settings' link on the config page.
1093  */
1094 function filter_has_global_settings($filter) {
1095     global $CFG;
1096     $settingspath = $CFG->dirroot . '/' . $filter . '/filtersettings.php';
1097     return is_readable($settingspath);
1098 }
1099
1100 /**
1101  * Does this filter have local (per-context) settings?
1102  *
1103  * @param string $filter The filter name, for example 'filter/tex' or 'mod/glossary'.
1104  * @return boolean Whether there should be a 'Settings' link on the manage filters in context page.
1105  */
1106 function filter_has_local_settings($filter) {
1107     global $CFG;
1108     $settingspath = $CFG->dirroot . '/' . $filter . '/filterlocalsettings.php';
1109     return is_readable($settingspath);
1110 }
1111
1112 /**
1113  * Certain types of context (block and user) may not have local filter settings.
1114  * the function checks a context to see whether it may have local config.
1115  *
1116  * @param object $context a context.
1117  * @return boolean whether this context may have local filter settings.
1118  */
1119 function filter_context_may_have_filter_settings($context) {
1120     return $context->contextlevel != CONTEXT_BLOCK && $context->contextlevel != CONTEXT_USER;
1121 }
1122
1123 /**
1124  * Process phrases intelligently found within a HTML text (such as adding links)
1125  *
1126  * @staticvar array $usedpharses
1127  * @param string $text             the text that we are filtering
1128  * @param array $link_array       an array of filterobjects
1129  * @param array $ignoretagsopen   an array of opening tags that we should ignore while filtering
1130  * @param array $ignoretagsclose  an array of corresponding closing tags
1131  * @param bool $overridedefaultignore True to only use tags provided by arguments
1132  * @return string
1133  **/
1134 function filter_phrases($text, &$link_array, $ignoretagsopen=NULL, $ignoretagsclose=NULL,
1135         $overridedefaultignore=false) {
1136
1137     global $CFG;
1138
1139     static $usedphrases;
1140
1141     $ignoretags = array();  //To store all the enclosig tags to be completely ignored
1142     $tags = array();        //To store all the simple tags to be ignored
1143
1144     if (!$overridedefaultignore) {
1145         // A list of open/close tags that we should not replace within
1146         // Extended to include <script>, <textarea>, <select> and <a> tags
1147         // Regular expression allows tags with or without attributes
1148         $filterignoretagsopen  = array('<head>' , '<nolink>' , '<span class="nolink">',
1149                 '<script(\s[^>]*?)?>', '<textarea(\s[^>]*?)?>',
1150                 '<select(\s[^>]*?)?>', '<a(\s[^>]*?)?>');
1151         $filterignoretagsclose = array('</head>', '</nolink>', '</span>',
1152                  '</script>', '</textarea>', '</select>','</a>');
1153     } else {
1154         // Set an empty default list
1155         $filterignoretagsopen = array();
1156         $filterignoretagsclose = array();
1157     }
1158
1159     // Add the user defined ignore tags to the default list
1160     if ( is_array($ignoretagsopen) ) {
1161         foreach ($ignoretagsopen as $open) {
1162             $filterignoretagsopen[] = $open;
1163         }
1164         foreach ($ignoretagsclose as $close) {
1165             $filterignoretagsclose[] = $close;
1166         }
1167     }
1168
1169 /// Invalid prefixes and suffixes for the fullmatch searches
1170 /// Every "word" character, but the underscore, is a invalid suffix or prefix.
1171 /// (nice to use this because it includes national characters (accents...) as word characters.
1172     $filterinvalidprefixes = '([^\W_])';
1173     $filterinvalidsuffixes = '([^\W_])';
1174
1175     //// Double up some magic chars to avoid "accidental matches"
1176     $text = preg_replace('/([#*%])/','\1\1',$text);
1177
1178
1179 ////Remove everything enclosed by the ignore tags from $text
1180     filter_save_ignore_tags($text,$filterignoretagsopen,$filterignoretagsclose,$ignoretags);
1181
1182 /// Remove tags from $text
1183     filter_save_tags($text,$tags);
1184
1185 /// Time to cycle through each phrase to be linked
1186     $size = sizeof($link_array);
1187     for ($n=0; $n < $size; $n++) {
1188         $linkobject =& $link_array[$n];
1189
1190     /// Set some defaults if certain properties are missing
1191     /// Properties may be missing if the filterobject class has not been used to construct the object
1192         if (empty($linkobject->phrase)) {
1193             continue;
1194         }
1195
1196     /// Avoid integers < 1000 to be linked. See bug 1446.
1197         $intcurrent = intval($linkobject->phrase);
1198         if (!empty($intcurrent) && strval($intcurrent) == $linkobject->phrase && $intcurrent < 1000) {
1199             continue;
1200         }
1201
1202     /// All this work has to be done ONLY it it hasn't been done before
1203     if (!$linkobject->work_calculated) {
1204             if (!isset($linkobject->hreftagbegin) or !isset($linkobject->hreftagend)) {
1205                 $linkobject->work_hreftagbegin = '<span class="highlight"';
1206                 $linkobject->work_hreftagend   = '</span>';
1207             } else {
1208                 $linkobject->work_hreftagbegin = $linkobject->hreftagbegin;
1209                 $linkobject->work_hreftagend   = $linkobject->hreftagend;
1210             }
1211
1212         /// Double up chars to protect true duplicates
1213         /// be cleared up before returning to the user.
1214             $linkobject->work_hreftagbegin = preg_replace('/([#*%])/','\1\1',$linkobject->work_hreftagbegin);
1215
1216             if (empty($linkobject->casesensitive)) {
1217                 $linkobject->work_casesensitive = false;
1218             } else {
1219                 $linkobject->work_casesensitive = true;
1220             }
1221             if (empty($linkobject->fullmatch)) {
1222                 $linkobject->work_fullmatch = false;
1223             } else {
1224                 $linkobject->work_fullmatch = true;
1225             }
1226
1227         /// Strip tags out of the phrase
1228             $linkobject->work_phrase = strip_tags($linkobject->phrase);
1229
1230         /// Double up chars that might cause a false match -- the duplicates will
1231         /// be cleared up before returning to the user.
1232             $linkobject->work_phrase = preg_replace('/([#*%])/','\1\1',$linkobject->work_phrase);
1233
1234         /// Set the replacement phrase properly
1235             if ($linkobject->replacementphrase) {    //We have specified a replacement phrase
1236             /// Strip tags
1237                 $linkobject->work_replacementphrase = strip_tags($linkobject->replacementphrase);
1238             } else {                                 //The replacement is the original phrase as matched below
1239                 $linkobject->work_replacementphrase = '$1';
1240             }
1241
1242         /// Quote any regular expression characters and the delimiter in the work phrase to be searched
1243             $linkobject->work_phrase = preg_quote($linkobject->work_phrase, '/');
1244
1245         /// Work calculated
1246             $linkobject->work_calculated = true;
1247
1248         }
1249
1250     /// If $CFG->filtermatchoneperpage, avoid previously (request) linked phrases
1251         if (!empty($CFG->filtermatchoneperpage)) {
1252             if (!empty($usedphrases) && in_array($linkobject->work_phrase,$usedphrases)) {
1253                 continue;
1254             }
1255         }
1256
1257     /// Regular expression modifiers
1258         $modifiers = ($linkobject->work_casesensitive) ? 's' : 'isu'; // works in unicode mode!
1259
1260     /// Do we need to do a fullmatch?
1261     /// If yes then go through and remove any non full matching entries
1262         if ($linkobject->work_fullmatch) {
1263             $notfullmatches = array();
1264             $regexp = '/'.$filterinvalidprefixes.'('.$linkobject->work_phrase.')|('.$linkobject->work_phrase.')'.$filterinvalidsuffixes.'/'.$modifiers;
1265
1266             preg_match_all($regexp,$text,$list_of_notfullmatches);
1267
1268             if ($list_of_notfullmatches) {
1269                 foreach (array_unique($list_of_notfullmatches[0]) as $key=>$value) {
1270                     $notfullmatches['<*'.$key.'*>'] = $value;
1271                 }
1272                 if (!empty($notfullmatches)) {
1273                     $text = str_replace($notfullmatches,array_keys($notfullmatches),$text);
1274                 }
1275             }
1276         }
1277
1278     /// Finally we do our highlighting
1279         if (!empty($CFG->filtermatchonepertext) || !empty($CFG->filtermatchoneperpage)) {
1280             $resulttext = preg_replace('/('.$linkobject->work_phrase.')/'.$modifiers,
1281                                       $linkobject->work_hreftagbegin.
1282                                       $linkobject->work_replacementphrase.
1283                                       $linkobject->work_hreftagend, $text, 1);
1284         } else {
1285             $resulttext = preg_replace('/('.$linkobject->work_phrase.')/'.$modifiers,
1286                                       $linkobject->work_hreftagbegin.
1287                                       $linkobject->work_replacementphrase.
1288                                       $linkobject->work_hreftagend, $text);
1289         }
1290
1291
1292     /// If the text has changed we have to look for links again
1293         if ($resulttext != $text) {
1294         /// Set $text to $resulttext
1295             $text = $resulttext;
1296         /// Remove everything enclosed by the ignore tags from $text
1297             filter_save_ignore_tags($text,$filterignoretagsopen,$filterignoretagsclose,$ignoretags);
1298         /// Remove tags from $text
1299             filter_save_tags($text,$tags);
1300         /// If $CFG->filtermatchoneperpage, save linked phrases to request
1301             if (!empty($CFG->filtermatchoneperpage)) {
1302                 $usedphrases[] = $linkobject->work_phrase;
1303             }
1304         }
1305
1306
1307     /// Replace the not full matches before cycling to next link object
1308         if (!empty($notfullmatches)) {
1309             $text = str_replace(array_keys($notfullmatches),$notfullmatches,$text);
1310             unset($notfullmatches);
1311         }
1312     }
1313
1314 /// Rebuild the text with all the excluded areas
1315
1316     if (!empty($tags)) {
1317         $text = str_replace(array_keys($tags), $tags, $text);
1318     }
1319
1320     if (!empty($ignoretags)) {
1321         $ignoretags = array_reverse($ignoretags); /// Reversed so "progressive" str_replace() will solve some nesting problems.
1322         $text = str_replace(array_keys($ignoretags),$ignoretags,$text);
1323     }
1324
1325     //// Remove the protective doubleups
1326     $text =  preg_replace('/([#*%])(\1)/','\1',$text);
1327
1328 /// Add missing javascript for popus
1329     $text = filter_add_javascript($text);
1330
1331
1332     return $text;
1333 }
1334
1335 /**
1336  * @todo Document this function
1337  * @param array $linkarray
1338  * @return array
1339  */
1340 function filter_remove_duplicates($linkarray) {
1341
1342     $concepts  = array(); // keep a record of concepts as we cycle through
1343     $lconcepts = array(); // a lower case version for case insensitive
1344
1345     $cleanlinks = array();
1346
1347     foreach ($linkarray as $key=>$filterobject) {
1348         if ($filterobject->casesensitive) {
1349             $exists = in_array($filterobject->phrase, $concepts);
1350         } else {
1351             $exists = in_array(textlib::strtolower($filterobject->phrase), $lconcepts);
1352         }
1353
1354         if (!$exists) {
1355             $cleanlinks[] = $filterobject;
1356             $concepts[] = $filterobject->phrase;
1357             $lconcepts[] = textlib::strtolower($filterobject->phrase);
1358         }
1359     }
1360
1361     return $cleanlinks;
1362 }
1363
1364 /**
1365  * Extract open/lose tags and their contents to avoid being processed by filters.
1366  * Useful to extract pieces of code like <a>...</a> tags. It returns the text
1367  * converted with some <#xTEXTFILTER_EXCL_SEPARATORx#> codes replacing the extracted text. Such extracted
1368  * texts are returned in the ignoretags array (as values), with codes as keys.
1369  *
1370  * @param string $text                  the text that we are filtering (in/out)
1371  * @param array $filterignoretagsopen  an array of open tags to start searching
1372  * @param array $filterignoretagsclose an array of close tags to end searching
1373  * @param array $ignoretags            an array of saved strings useful to rebuild the original text (in/out)
1374  **/
1375 function filter_save_ignore_tags(&$text, $filterignoretagsopen, $filterignoretagsclose, &$ignoretags) {
1376
1377 /// Remove everything enclosed by the ignore tags from $text
1378     foreach ($filterignoretagsopen as $ikey=>$opentag) {
1379         $closetag = $filterignoretagsclose[$ikey];
1380     /// form regular expression
1381         $opentag  = str_replace('/','\/',$opentag); // delimit forward slashes
1382         $closetag = str_replace('/','\/',$closetag); // delimit forward slashes
1383         $pregexp = '/'.$opentag.'(.*?)'.$closetag.'/is';
1384
1385         preg_match_all($pregexp, $text, $list_of_ignores);
1386         foreach (array_unique($list_of_ignores[0]) as $key=>$value) {
1387             $prefix = (string)(count($ignoretags) + 1);
1388             $ignoretags['<#'.$prefix.TEXTFILTER_EXCL_SEPARATOR.$key.'#>'] = $value;
1389         }
1390         if (!empty($ignoretags)) {
1391             $text = str_replace($ignoretags,array_keys($ignoretags),$text);
1392         }
1393     }
1394 }
1395
1396 /**
1397  * Extract tags (any text enclosed by < and > to avoid being processed by filters.
1398  * It returns the text converted with some <%xTEXTFILTER_EXCL_SEPARATORx%> codes replacing the extracted text. Such extracted
1399  * texts are returned in the tags array (as values), with codes as keys.
1400  *
1401  * @param string $text   the text that we are filtering (in/out)
1402  * @param array $tags   an array of saved strings useful to rebuild the original text (in/out)
1403  **/
1404 function filter_save_tags(&$text, &$tags) {
1405
1406     preg_match_all('/<([^#%*].*?)>/is',$text,$list_of_newtags);
1407     foreach (array_unique($list_of_newtags[0]) as $ntkey=>$value) {
1408         $prefix = (string)(count($tags) + 1);
1409         $tags['<%'.$prefix.TEXTFILTER_EXCL_SEPARATOR.$ntkey.'%>'] = $value;
1410     }
1411     if (!empty($tags)) {
1412         $text = str_replace($tags,array_keys($tags),$text);
1413     }
1414 }
1415
1416 /**
1417  * Add missing openpopup javascript to HTML files.
1418  *
1419  * @param string $text
1420  * @return string
1421  */
1422 function filter_add_javascript($text) {
1423     global $CFG;
1424
1425     if (stripos($text, '</html>') === FALSE) {
1426         return $text; // this is not a html file
1427     }
1428     if (strpos($text, 'onclick="return openpopup') === FALSE) {
1429         return $text; // no popup - no need to add javascript
1430     }
1431     $js ="
1432     <script type=\"text/javascript\">
1433     <!--
1434         function openpopup(url,name,options,fullscreen) {
1435           fullurl = \"".$CFG->httpswwwroot."\" + url;
1436           windowobj = window.open(fullurl,name,options);
1437           if (fullscreen) {
1438             windowobj.moveTo(0,0);
1439             windowobj.resizeTo(screen.availWidth,screen.availHeight);
1440           }
1441           windowobj.focus();
1442           return false;
1443         }
1444     // -->
1445     </script>";
1446     if (stripos($text, '</head>') !== FALSE) {
1447         //try to add it into the head element
1448         $text = str_ireplace('</head>', $js.'</head>', $text);
1449         return $text;
1450     }
1451
1452     //last chance - try adding head element
1453     return preg_replace("/<html.*?>/is", "\\0<head>".$js.'</head>', $text);
1454 }