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  • Bug fixes for general core bugs in 2.8.x ended 9 November 2015 (12 months).
  • Bug fixes for security issues in 2.8.x ended 9 May 2016 (18 months).
  • minimum PHP 5.4.4 (always use latest PHP 5.4.x or 5.5.x on Windows - http://windows.php.net/download/), PHP 7 is NOT supported
  • /lib/ -> modinfolib.php (source)

    Differences Between: [Versions 28 and 29] [Versions 28 and 30] [Versions 28 and 31] [Versions 28 and 32] [Versions 28 and 33] [Versions 28 and 34] [Versions 28 and 35] [Versions 28 and 36] [Versions 28 and 37]

       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   * modinfolib.php - Functions/classes relating to cached information about module instances on
      19   * a course.
      20   * @package    core
      21   * @subpackage lib
      22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
      23   * @author     sam marshall
      24   */
      25  
      26  
      27  // Maximum number of modinfo items to keep in memory cache. Do not increase this to a large
      28  // number because:
      29  // a) modinfo can be big (megabyte range) for some courses
      30  // b) performance of cache will deteriorate if there are very many items in it
      31  if (!defined('MAX_MODINFO_CACHE_SIZE')) {
      32      define('MAX_MODINFO_CACHE_SIZE', 10);
      33  }
      34  
      35  
      36  /**
      37   * Information about a course that is cached in the course table 'modinfo' field (and then in
      38   * memory) in order to reduce the need for other database queries.
      39   *
      40   * This includes information about the course-modules and the sections on the course. It can also
      41   * include dynamic data that has been updated for the current user.
      42   *
      43   * Use {@link get_fast_modinfo()} to retrieve the instance of the object for particular course
      44   * and particular user.
      45   *
      46   * @property-read int $courseid Course ID
      47   * @property-read int $userid User ID
      48   * @property-read array $sections Array from section number (e.g. 0) to array of course-module IDs in that
      49   *     section; this only includes sections that contain at least one course-module
      50   * @property-read cm_info[] $cms Array from course-module instance to cm_info object within this course, in
      51   *     order of appearance
      52   * @property-read cm_info[][] $instances Array from string (modname) => int (instance id) => cm_info object
      53   * @property-read array $groups Groups that the current user belongs to. Calculated on the first request.
      54   *     Is an array of grouping id => array of group id => group id. Includes grouping id 0 for 'all groups'
      55   */
      56  class course_modinfo {
      57      /**
      58       * List of fields from DB table 'course' that are cached in MUC and are always present in course_modinfo::$course
      59       * @var array
      60       */
      61      public static $cachedfields = array('shortname', 'fullname', 'format',
      62              'enablecompletion', 'groupmode', 'groupmodeforce', 'cacherev');
      63  
      64      /**
      65       * For convenience we store the course object here as it is needed in other parts of code
      66       * @var stdClass
      67       */
      68      private $course;
      69  
      70      /**
      71       * Array of section data from cache
      72       * @var section_info[]
      73       */
      74      private $sectioninfo;
      75  
      76      /**
      77       * User ID
      78       * @var int
      79       */
      80      private $userid;
      81  
      82      /**
      83       * Array from int (section num, e.g. 0) => array of int (course-module id); this list only
      84       * includes sections that actually contain at least one course-module
      85       * @var array
      86       */
      87      private $sections;
      88  
      89      /**
      90       * Array from int (cm id) => cm_info object
      91       * @var cm_info[]
      92       */
      93      private $cms;
      94  
      95      /**
      96       * Array from string (modname) => int (instance id) => cm_info object
      97       * @var cm_info[][]
      98       */
      99      private $instances;
     100  
     101      /**
     102       * Groups that the current user belongs to. This value is calculated on first
     103       * request to the property or function.
     104       * When set, it is an array of grouping id => array of group id => group id.
     105       * Includes grouping id 0 for 'all groups'.
     106       * @var int[][]
     107       */
     108      private $groups;
     109  
     110      /**
     111       * List of class read-only properties and their getter methods.
     112       * Used by magic functions __get(), __isset(), __empty()
     113       * @var array
     114       */
     115      private static $standardproperties = array(
     116          'courseid' => 'get_course_id',
     117          'userid' => 'get_user_id',
     118          'sections' => 'get_sections',
     119          'cms' => 'get_cms',
     120          'instances' => 'get_instances',
     121          'groups' => 'get_groups_all',
     122      );
     123  
     124      /**
     125       * Magic method getter
     126       *
     127       * @param string $name
     128       * @return mixed
     129       */
     130      public function __get($name) {
     131          if (isset(self::$standardproperties[$name])) {
     132              $method = self::$standardproperties[$name];
     133              return $this->$method();
     134          } else {
     135              debugging('Invalid course_modinfo property accessed: '.$name);
     136              return null;
     137          }
     138      }
     139  
     140      /**
     141       * Magic method for function isset()
     142       *
     143       * @param string $name
     144       * @return bool
     145       */
     146      public function __isset($name) {
     147          if (isset(self::$standardproperties[$name])) {
     148              $value = $this->__get($name);
     149              return isset($value);
     150          }
     151          return false;
     152      }
     153  
     154      /**
     155       * Magic method for function empty()
     156       *
     157       * @param string $name
     158       * @return bool
     159       */
     160      public function __empty($name) {
     161          if (isset(self::$standardproperties[$name])) {
     162              $value = $this->__get($name);
     163              return empty($value);
     164          }
     165          return true;
     166      }
     167  
     168      /**
     169       * Magic method setter
     170       *
     171       * Will display the developer warning when trying to set/overwrite existing property.
     172       *
     173       * @param string $name
     174       * @param mixed $value
     175       */
     176      public function __set($name, $value) {
     177          debugging("It is not allowed to set the property course_modinfo::\${$name}", DEBUG_DEVELOPER);
     178      }
     179  
     180      /**
     181       * Returns course object that was used in the first {@link get_fast_modinfo()} call.
     182       *
     183       * It may not contain all fields from DB table {course} but always has at least the following:
     184       * id,shortname,fullname,format,enablecompletion,groupmode,groupmodeforce,cacherev
     185       *
     186       * @return stdClass
     187       */
     188      public function get_course() {
     189          return $this->course;
     190      }
     191  
     192      /**
     193       * @return int Course ID
     194       */
     195      public function get_course_id() {
     196          return $this->course->id;
     197      }
     198  
     199      /**
     200       * @return int User ID
     201       */
     202      public function get_user_id() {
     203          return $this->userid;
     204      }
     205  
     206      /**
     207       * @return array Array from section number (e.g. 0) to array of course-module IDs in that
     208       *   section; this only includes sections that contain at least one course-module
     209       */
     210      public function get_sections() {
     211          return $this->sections;
     212      }
     213  
     214      /**
     215       * @return cm_info[] Array from course-module instance to cm_info object within this course, in
     216       *   order of appearance
     217       */
     218      public function get_cms() {
     219          return $this->cms;
     220      }
     221  
     222      /**
     223       * Obtains a single course-module object (for a course-module that is on this course).
     224       * @param int $cmid Course-module ID
     225       * @return cm_info Information about that course-module
     226       * @throws moodle_exception If the course-module does not exist
     227       */
     228      public function get_cm($cmid) {
     229          if (empty($this->cms[$cmid])) {
     230              throw new moodle_exception('invalidcoursemodule', 'error');
     231          }
     232          return $this->cms[$cmid];
     233      }
     234  
     235      /**
     236       * Obtains all module instances on this course.
     237       * @return cm_info[][] Array from module name => array from instance id => cm_info
     238       */
     239      public function get_instances() {
     240          return $this->instances;
     241      }
     242  
     243      /**
     244       * Returns array of localised human-readable module names used in this course
     245       *
     246       * @param bool $plural if true returns the plural form of modules names
     247       * @return array
     248       */
     249      public function get_used_module_names($plural = false) {
     250          $modnames = get_module_types_names($plural);
     251          $modnamesused = array();
     252          foreach ($this->get_cms() as $cmid => $mod) {
     253              if (isset($modnames[$mod->modname]) && $mod->uservisible) {
     254                  $modnamesused[$mod->modname] = $modnames[$mod->modname];
     255              }
     256          }
     257          core_collator::asort($modnamesused);
     258          return $modnamesused;
     259      }
     260  
     261      /**
     262       * Obtains all instances of a particular module on this course.
     263       * @param $modname Name of module (not full frankenstyle) e.g. 'label'
     264       * @return cm_info[] Array from instance id => cm_info for modules on this course; empty if none
     265       */
     266      public function get_instances_of($modname) {
     267          if (empty($this->instances[$modname])) {
     268              return array();
     269          }
     270          return $this->instances[$modname];
     271      }
     272  
     273      /**
     274       * Groups that the current user belongs to organised by grouping id. Calculated on the first request.
     275       * @return int[][] array of grouping id => array of group id => group id. Includes grouping id 0 for 'all groups'
     276       */
     277      private function get_groups_all() {
     278          if (is_null($this->groups)) {
     279              // NOTE: Performance could be improved here. The system caches user groups
     280              // in $USER->groupmember[$courseid] => array of groupid=>groupid. Unfortunately this
     281              // structure does not include grouping information. It probably could be changed to
     282              // do so, without a significant performance hit on login, thus saving this one query
     283              // each request.
     284              $this->groups = groups_get_user_groups($this->course->id, $this->userid);
     285          }
     286          return $this->groups;
     287      }
     288  
     289      /**
     290       * Returns groups that the current user belongs to on the course. Note: If not already
     291       * available, this may make a database query.
     292       * @param int $groupingid Grouping ID or 0 (default) for all groups
     293       * @return int[] Array of int (group id) => int (same group id again); empty array if none
     294       */
     295      public function get_groups($groupingid = 0) {
     296          $allgroups = $this->get_groups_all();
     297          if (!isset($allgroups[$groupingid])) {
     298              return array();
     299          }
     300          return $allgroups[$groupingid];
     301      }
     302  
     303      /**
     304       * Gets all sections as array from section number => data about section.
     305       * @return section_info[] Array of section_info objects organised by section number
     306       */
     307      public function get_section_info_all() {
     308          return $this->sectioninfo;
     309      }
     310  
     311      /**
     312       * Gets data about specific numbered section.
     313       * @param int $sectionnumber Number (not id) of section
     314       * @param int $strictness Use MUST_EXIST to throw exception if it doesn't
     315       * @return section_info Information for numbered section or null if not found
     316       */
     317      public function get_section_info($sectionnumber, $strictness = IGNORE_MISSING) {
     318          if (!array_key_exists($sectionnumber, $this->sectioninfo)) {
     319              if ($strictness === MUST_EXIST) {
     320                  throw new moodle_exception('sectionnotexist');
     321              } else {
     322                  return null;
     323              }
     324          }
     325          return $this->sectioninfo[$sectionnumber];
     326      }
     327  
     328      /**
     329       * Static cache for generated course_modinfo instances
     330       *
     331       * @see course_modinfo::instance()
     332       * @see course_modinfo::clear_instance_cache()
     333       * @var course_modinfo[]
     334       */
     335      protected static $instancecache = array();
     336  
     337      /**
     338       * Timestamps (microtime) when the course_modinfo instances were last accessed
     339       *
     340       * It is used to remove the least recent accessed instances when static cache is full
     341       *
     342       * @var float[]
     343       */
     344      protected static $cacheaccessed = array();
     345  
     346      /**
     347       * Clears the cache used in course_modinfo::instance()
     348       *
     349       * Used in {@link get_fast_modinfo()} when called with argument $reset = true
     350       * and in {@link rebuild_course_cache()}
     351       *
     352       * @param null|int|stdClass $courseorid if specified removes only cached value for this course
     353       */
     354      public static function clear_instance_cache($courseorid = null) {
     355          if (empty($courseorid)) {
     356              self::$instancecache = array();
     357              self::$cacheaccessed = array();
     358              return;
     359          }
     360          if (is_object($courseorid)) {
     361              $courseorid = $courseorid->id;
     362          }
     363          if (isset(self::$instancecache[$courseorid])) {
     364              // Unsetting static variable in PHP is peculiar, it removes the reference,
     365              // but data remain in memory. Prior to unsetting, the varable needs to be
     366              // set to empty to remove its remains from memory.
     367              self::$instancecache[$courseorid] = '';
     368              unset(self::$instancecache[$courseorid]);
     369              unset(self::$cacheaccessed[$courseorid]);
     370          }
     371      }
     372  
     373      /**
     374       * Returns the instance of course_modinfo for the specified course and specified user
     375       *
     376       * This function uses static cache for the retrieved instances. The cache
     377       * size is limited by MAX_MODINFO_CACHE_SIZE. If instance is not found in
     378       * the static cache or it was created for another user or the cacherev validation
     379       * failed - a new instance is constructed and returned.
     380       *
     381       * Used in {@link get_fast_modinfo()}
     382       *
     383       * @param int|stdClass $courseorid object from DB table 'course' (must have field 'id'
     384       *     and recommended to have field 'cacherev') or just a course id
     385       * @param int $userid User id to populate 'availble' and 'uservisible' attributes of modules and sections.
     386       *     Set to 0 for current user (default). Set to -1 to avoid calculation of dynamic user-depended data.
     387       * @return course_modinfo
     388       */
     389      public static function instance($courseorid, $userid = 0) {
     390          global $USER;
     391          if (is_object($courseorid)) {
     392              $course = $courseorid;
     393          } else {
     394              $course = (object)array('id' => $courseorid);
     395          }
     396          if (empty($userid)) {
     397              $userid = $USER->id;
     398          }
     399  
     400          if (!empty(self::$instancecache[$course->id])) {
     401              if (self::$instancecache[$course->id]->userid == $userid &&
     402                      (!isset($course->cacherev) ||
     403                      $course->cacherev == self::$instancecache[$course->id]->get_course()->cacherev)) {
     404                  // This course's modinfo for the same user was recently retrieved, return cached.
     405                  self::$cacheaccessed[$course->id] = microtime(true);
     406                  return self::$instancecache[$course->id];
     407              } else {
     408                  // Prevent potential reference problems when switching users.
     409                  self::clear_instance_cache($course->id);
     410              }
     411          }
     412          $modinfo = new course_modinfo($course, $userid);
     413  
     414          // We have a limit of MAX_MODINFO_CACHE_SIZE entries to store in static variable.
     415          if (count(self::$instancecache) >= MAX_MODINFO_CACHE_SIZE) {
     416              // Find the course that was the least recently accessed.
     417              asort(self::$cacheaccessed, SORT_NUMERIC);
     418              $courseidtoremove = key(array_reverse(self::$cacheaccessed, true));
     419              self::clear_instance_cache($courseidtoremove);
     420          }
     421  
     422          // Add modinfo to the static cache.
     423          self::$instancecache[$course->id] = $modinfo;
     424          self::$cacheaccessed[$course->id] = microtime(true);
     425  
     426          return $modinfo;
     427      }
     428  
     429      /**
     430       * Constructs based on course.
     431       * Note: This constructor should not usually be called directly.
     432       * Use get_fast_modinfo($course) instead as this maintains a cache.
     433       * @param stdClass $course course object, only property id is required.
     434       * @param int $userid User ID
     435       * @throws moodle_exception if course is not found
     436       */
     437      public function __construct($course, $userid) {
     438          global $CFG, $COURSE, $SITE, $DB;
     439  
     440          if (!isset($course->cacherev)) {
     441              // We require presence of property cacherev to validate the course cache.
     442              // No need to clone the $COURSE or $SITE object here because we clone it below anyway.
     443              $course = get_course($course->id, false);
     444          }
     445  
     446          $cachecoursemodinfo = cache::make('core', 'coursemodinfo');
     447  
     448          // Retrieve modinfo from cache. If not present or cacherev mismatches, call rebuild and retrieve again.
     449          $coursemodinfo = $cachecoursemodinfo->get($course->id);
     450          if ($coursemodinfo === false || ($course->cacherev != $coursemodinfo->cacherev)) {
     451              $coursemodinfo = self::build_course_cache($course);
     452          }
     453  
     454          // Set initial values
     455          $this->userid = $userid;
     456          $this->sections = array();
     457          $this->cms = array();
     458          $this->instances = array();
     459          $this->groups = null;
     460  
     461          // If we haven't already preloaded contexts for the course, do it now
     462          // Modules are also cached here as long as it's the first time this course has been preloaded.
     463          context_helper::preload_course($course->id);
     464  
     465          // Quick integrity check: as a result of race conditions modinfo may not be regenerated after the change.
     466          // It is especially dangerous if modinfo contains the deleted course module, as it results in fatal error.
     467          // We can check it very cheap by validating the existence of module context.
     468          if ($course->id == $COURSE->id || $course->id == $SITE->id) {
     469              // Only verify current course (or frontpage) as pages with many courses may not have module contexts cached.
     470              // (Uncached modules will result in a very slow verification).
     471              foreach ($coursemodinfo->modinfo as $mod) {
     472                  if (!context_module::instance($mod->cm, IGNORE_MISSING)) {
     473                      debugging('Course cache integrity check failed: course module with id '. $mod->cm.
     474                              ' does not have context. Rebuilding cache for course '. $course->id);
     475                      // Re-request the course record from DB as well, don't use get_course() here.
     476                      $course = $DB->get_record('course', array('id' => $course->id), '*', MUST_EXIST);
     477                      $coursemodinfo = self::build_course_cache($course);
     478                      break;
     479                  }
     480              }
     481          }
     482  
     483          // Overwrite unset fields in $course object with cached values, store the course object.
     484          $this->course = fullclone($course);
     485          foreach ($coursemodinfo as $key => $value) {
     486              if ($key !== 'modinfo' && $key !== 'sectioncache' &&
     487                      (!isset($this->course->$key) || $key === 'cacherev')) {
     488                  $this->course->$key = $value;
     489              }
     490          }
     491  
     492          // Loop through each piece of module data, constructing it
     493          static $modexists = array();
     494          foreach ($coursemodinfo->modinfo as $mod) {
     495              if (strval($mod->name) === '') {
     496                  // something is wrong here
     497                  continue;
     498              }
     499  
     500              // Skip modules which don't exist
     501              if (!array_key_exists($mod->mod, $modexists)) {
     502                  $modexists[$mod->mod] = file_exists("$CFG->dirroot/mod/$mod->mod/lib.php");
     503              }
     504              if (!$modexists[$mod->mod]) {
     505                  continue;
     506              }
     507  
     508              // Construct info for this module
     509              $cm = new cm_info($this, null, $mod, null);
     510  
     511              // Store module in instances and cms array
     512              if (!isset($this->instances[$cm->modname])) {
     513                  $this->instances[$cm->modname] = array();
     514              }
     515              $this->instances[$cm->modname][$cm->instance] = $cm;
     516              $this->cms[$cm->id] = $cm;
     517  
     518              // Reconstruct sections. This works because modules are stored in order
     519              if (!isset($this->sections[$cm->sectionnum])) {
     520                  $this->sections[$cm->sectionnum] = array();
     521              }
     522              $this->sections[$cm->sectionnum][] = $cm->id;
     523          }
     524  
     525          // Expand section objects
     526          $this->sectioninfo = array();
     527          foreach ($coursemodinfo->sectioncache as $number => $data) {
     528              $this->sectioninfo[$number] = new section_info($data, $number, null, null,
     529                      $this, null);
     530          }
     531      }
     532  
     533      /**
     534       * Builds a list of information about sections on a course to be stored in
     535       * the course cache. (Does not include information that is already cached
     536       * in some other way.)
     537       *
     538       * This function will be removed in 2.7
     539       *
     540       * @deprecated since 2.6
     541       * @param int $courseid Course ID
     542       * @return array Information about sections, indexed by section number (not id)
     543       */
     544      public static function build_section_cache($courseid) {
     545          global $DB;
     546          debugging('Function course_modinfo::build_section_cache() is deprecated. It can only be used internally to build course cache.');
     547          $course = $DB->get_record('course', array('id' => $course->id),
     548                          array_merge(array('id'), self::$cachedfields), MUST_EXIST);
     549          return self::build_course_section_cache($course);
     550      }
     551  
     552      /**
     553       * Builds a list of information about sections on a course to be stored in
     554       * the course cache. (Does not include information that is already cached
     555       * in some other way.)
     556       *
     557       * @param stdClass $course Course object (must contain fields
     558       * @return array Information about sections, indexed by section number (not id)
     559       */
     560      protected static function build_course_section_cache($course) {
     561          global $DB;
     562  
     563          // Get section data
     564          $sections = $DB->get_records('course_sections', array('course' => $course->id), 'section',
     565                  'section, id, course, name, summary, summaryformat, sequence, visible, ' .
     566                  'availability');
     567          $compressedsections = array();
     568  
     569          $formatoptionsdef = course_get_format($course)->section_format_options();
     570          // Remove unnecessary data and add availability
     571          foreach ($sections as $number => $section) {
     572              // Add cached options from course format to $section object
     573              foreach ($formatoptionsdef as $key => $option) {
     574                  if (!empty($option['cache'])) {
     575                      $formatoptions = course_get_format($course)->get_format_options($section);
     576                      if (!array_key_exists('cachedefault', $option) || $option['cachedefault'] !== $formatoptions[$key]) {
     577                          $section->$key = $formatoptions[$key];
     578                      }
     579                  }
     580              }
     581              // Clone just in case it is reused elsewhere
     582              $compressedsections[$number] = clone($section);
     583              section_info::convert_for_section_cache($compressedsections[$number]);
     584          }
     585  
     586          return $compressedsections;
     587      }
     588  
     589      /**
     590       * Builds and stores in MUC object containing information about course
     591       * modules and sections together with cached fields from table course.
     592       *
     593       * @param stdClass $course object from DB table course. Must have property 'id'
     594       *     but preferably should have all cached fields.
     595       * @return stdClass object with all cached keys of the course plus fields modinfo and sectioncache.
     596       *     The same object is stored in MUC
     597       * @throws moodle_exception if course is not found (if $course object misses some of the
     598       *     necessary fields it is re-requested from database)
     599       */
     600      public static function build_course_cache($course) {
     601          global $DB, $CFG;
     602          require_once("$CFG->dirroot/course/lib.php");
     603          if (empty($course->id)) {
     604              throw new coding_exception('Object $course is missing required property \id\'');
     605          }
     606          // Ensure object has all necessary fields.
     607          foreach (self::$cachedfields as $key) {
     608              if (!isset($course->$key)) {
     609                  $course = $DB->get_record('course', array('id' => $course->id),
     610                          implode(',', array_merge(array('id'), self::$cachedfields)), MUST_EXIST);
     611                  break;
     612              }
     613          }
     614          // Retrieve all information about activities and sections.
     615          // This may take time on large courses and it is possible that another user modifies the same course during this process.
     616          // Field cacherev stored in both DB and cache will ensure that cached data matches the current course state.
     617          $coursemodinfo = new stdClass();
     618          $coursemodinfo->modinfo = get_array_of_activities($course->id);
     619          $coursemodinfo->sectioncache = self::build_course_section_cache($course);
     620          foreach (self::$cachedfields as $key) {
     621              $coursemodinfo->$key = $course->$key;
     622          }
     623          // Set the accumulated activities and sections information in cache, together with cacherev.
     624          $cachecoursemodinfo = cache::make('core', 'coursemodinfo');
     625          $cachecoursemodinfo->set($course->id, $coursemodinfo);
     626          return $coursemodinfo;
     627      }
     628  }
     629  
     630  
     631  /**
     632   * Data about a single module on a course. This contains most of the fields in the course_modules
     633   * table, plus additional data when required.
     634   *
     635   * The object can be accessed by core or any plugin (i.e. course format, block, filter, etc.) as
     636   * get_fast_modinfo($courseorid)->cms[$coursemoduleid]
     637   * or
     638   * get_fast_modinfo($courseorid)->instances[$moduletype][$instanceid]
     639   *
     640   * There are three stages when activity module can add/modify data in this object:
     641   *
     642   * <b>Stage 1 - during building the cache.</b>
     643   * Allows to add to the course cache static user-independent information about the module.
     644   * Modules should try to include only absolutely necessary information that may be required
     645   * when displaying course view page. The information is stored in application-level cache
     646   * and reset when {@link rebuild_course_cache()} is called or cache is purged by admin.
     647   *
     648   * Modules can implement callback XXX_get_coursemodule_info() returning instance of object
     649   * {@link cached_cm_info}
     650   *
     651   * <b>Stage 2 - dynamic data.</b>
     652   * Dynamic data is user-dependend, it is stored in request-level cache. To reset this cache
     653   * {@link get_fast_modinfo()} with $reset argument may be called.
     654   *
     655   * Dynamic data is obtained when any of the following properties/methods is requested:
     656   * - {@link cm_info::$url}
     657   * - {@link cm_info::$name}
     658   * - {@link cm_info::$onclick}
     659   * - {@link cm_info::get_icon_url()}
     660   * - {@link cm_info::$uservisible}
     661   * - {@link cm_info::$available}
     662   * - {@link cm_info::$availableinfo}
     663   * - plus any of the properties listed in Stage 3.
     664   *
     665   * Modules can implement callback <b>XXX_cm_info_dynamic()</b> and inside this callback they
     666   * are allowed to use any of the following set methods:
     667   * - {@link cm_info::set_available()}
     668   * - {@link cm_info::set_name()}
     669   * - {@link cm_info::set_no_view_link()}
     670   * - {@link cm_info::set_user_visible()}
     671   * - {@link cm_info::set_on_click()}
     672   * - {@link cm_info::set_icon_url()}
     673   * Any methods affecting view elements can also be set in this callback.
     674   *
     675   * <b>Stage 3 (view data).</b>
     676   * Also user-dependend data stored in request-level cache. Second stage is created
     677   * because populating the view data can be expensive as it may access much more
     678   * Moodle APIs such as filters, user information, output renderers and we
     679   * don't want to request it until necessary.
     680   * View data is obtained when any of the following properties/methods is requested:
     681   * - {@link cm_info::$afterediticons}
     682   * - {@link cm_info::$content}
     683   * - {@link cm_info::get_formatted_content()}
     684   * - {@link cm_info::$extraclasses}
     685   * - {@link cm_info::$afterlink}
     686   *
     687   * Modules can implement callback <b>XXX_cm_info_view()</b> and inside this callback they
     688   * are allowed to use any of the following set methods:
     689   * - {@link cm_info::set_after_edit_icons()}
     690   * - {@link cm_info::set_after_link()}
     691   * - {@link cm_info::set_content()}
     692   * - {@link cm_info::set_extra_classes()}
     693   *
     694   * @property-read int $id Course-module ID - from course_modules table
     695   * @property-read int $instance Module instance (ID within module table) - from course_modules table
     696   * @property-read int $course Course ID - from course_modules table
     697   * @property-read string $idnumber 'ID number' from course-modules table (arbitrary text set by user) - from
     698   *    course_modules table
     699   * @property-read int $added Time that this course-module was added (unix time) - from course_modules table
     700   * @property-read int $visible Visible setting (0 or 1; if this is 0, students cannot see/access the activity) - from
     701   *    course_modules table
     702   * @property-read int $visibleold Old visible setting (if the entire section is hidden, the previous value for
     703   *    visible is stored in this field) - from course_modules table
     704   * @property-read int $groupmode Group mode (one of the constants NOGROUPS, SEPARATEGROUPS, or VISIBLEGROUPS) - from
     705   *    course_modules table. Use {@link cm_info::$effectivegroupmode} to find the actual group mode that may be forced by course.
     706   * @property-read int $groupingid Grouping ID (0 = all groupings)
     707   * @property-read bool $coursegroupmodeforce Indicates whether the course containing the module has forced the groupmode
     708   *    This means that cm_info::$groupmode should be ignored and cm_info::$coursegroupmode be used instead
     709   * @property-read int $coursegroupmode Group mode (one of the constants NOGROUPS, SEPARATEGROUPS, or VISIBLEGROUPS) - from
     710   *    course table - as specified for the course containing the module
     711   *    Effective only if {@link cm_info::$coursegroupmodeforce} is set
     712   * @property-read int $effectivegroupmode Effective group mode for this module (one of the constants NOGROUPS, SEPARATEGROUPS,
     713   *    or VISIBLEGROUPS). This can be different from groupmode set for the module if the groupmode is forced for the course.
     714   *    This value will always be NOGROUPS if module type does not support group mode.
     715   * @property-read int $indent Indent level on course page (0 = no indent) - from course_modules table
     716   * @property-read int $completion Activity completion setting for this activity, COMPLETION_TRACKING_xx constant - from
     717   *    course_modules table
     718   * @property-read mixed $completiongradeitemnumber Set to the item number (usually 0) if completion depends on a particular
     719   *    grade of this activity, or null if completion does not depend on a grade - from course_modules table
     720   * @property-read int $completionview 1 if 'on view' completion is enabled, 0 otherwise - from course_modules table
     721   * @property-read int $completionexpected Set to a unix time if completion of this activity is expected at a
     722   *    particular time, 0 if no time set - from course_modules table
     723   * @property-read string $availability Availability information as JSON string or null if none -
     724   *    from course_modules table
     725   * @property-read int $showdescription Controls whether the description of the activity displays on the course main page (in
     726   *    addition to anywhere it might display within the activity itself). 0 = do not show
     727   *    on main page, 1 = show on main page.
     728   * @property-read string $extra (deprecated) Extra HTML that is put in an unhelpful part of the HTML when displaying this module in
     729   *    course page - from cached data in modinfo field. Deprecated, replaced by ->extraclasses and ->onclick
     730   * @property-read string $icon Name of icon to use - from cached data in modinfo field
     731   * @property-read string $iconcomponent Component that contains icon - from cached data in modinfo field
     732   * @property-read string $modname Name of module e.g. 'forum' (this is the same name as the module's main database
     733   *    table) - from cached data in modinfo field
     734   * @property-read int $module ID of module type - from course_modules table
     735   * @property-read string $name Name of module instance for display on page e.g. 'General discussion forum' - from cached
     736   *    data in modinfo field
     737   * @property-read int $sectionnum Section number that this course-module is in (section 0 = above the calendar, section 1
     738   *    = week/topic 1, etc) - from cached data in modinfo field
     739   * @property-read int $section Section id - from course_modules table
     740   * @property-read array $conditionscompletion Availability conditions for this course-module based on the completion of other
     741   *    course-modules (array from other course-module id to required completion state for that
     742   *    module) - from cached data in modinfo field
     743   * @property-read array $conditionsgrade Availability conditions for this course-module based on course grades (array from
     744   *    grade item id to object with ->min, ->max fields) - from cached data in modinfo field
     745   * @property-read array $conditionsfield Availability conditions for this course-module based on user fields
     746   * @property-read bool $available True if this course-module is available to students i.e. if all availability conditions
     747   *    are met - obtained dynamically
     748   * @property-read string $availableinfo If course-module is not available to students, this string gives information about
     749   *    availability which can be displayed to students and/or staff (e.g. 'Available from 3
     750   *    January 2010') for display on main page - obtained dynamically
     751   * @property-read bool $uservisible True if this course-module is available to the CURRENT user (for example, if current user
     752   *    has viewhiddenactivities capability, they can access the course-module even if it is not
     753   *    visible or not available, so this would be true in that case)
     754   * @property-read context_module $context Module context
     755   * @property-read string $modfullname Returns a localised human-readable name of the module type - calculated on request
     756   * @property-read string $modplural Returns a localised human-readable name of the module type in plural form - calculated on request
     757   * @property-read string $content Content to display on main (view) page - calculated on request
     758   * @property-read moodle_url $url URL to link to for this module, or null if it doesn't have a view page - calculated on request
     759   * @property-read string $extraclasses Extra CSS classes to add to html output for this activity on main page - calculated on request
     760   * @property-read string $onclick Content of HTML on-click attribute already escaped - calculated on request
     761   * @property-read mixed $customdata Optional custom data stored in modinfo cache for this activity, or null if none
     762   * @property-read string $afterlink Extra HTML code to display after link - calculated on request
     763   * @property-read string $afterediticons Extra HTML code to display after editing icons (e.g. more icons) - calculated on request
     764   */
     765  class cm_info implements IteratorAggregate {
     766      /**
     767       * State: Only basic data from modinfo cache is available.
     768       */
     769      const STATE_BASIC = 0;
     770  
     771      /**
     772       * State: In the process of building dynamic data (to avoid recursive calls to obtain_dynamic_data())
     773       */
     774      const STATE_BUILDING_DYNAMIC = 1;
     775  
     776      /**
     777       * State: Dynamic data is available too.
     778       */
     779      const STATE_DYNAMIC = 2;
     780  
     781      /**
     782       * State: In the process of building view data (to avoid recursive calls to obtain_view_data())
     783       */
     784      const STATE_BUILDING_VIEW = 3;
     785  
     786      /**
     787       * State: View data (for course page) is available.
     788       */
     789      const STATE_VIEW = 4;
     790  
     791      /**
     792       * Parent object
     793       * @var course_modinfo
     794       */
     795      private $modinfo;
     796  
     797      /**
     798       * Level of information stored inside this object (STATE_xx constant)
     799       * @var int
     800       */
     801      private $state;
     802  
     803      /**
     804       * Course-module ID - from course_modules table
     805       * @var int
     806       */
     807      private $id;
     808  
     809      /**
     810       * Module instance (ID within module table) - from course_modules table
     811       * @var int
     812       */
     813      private $instance;
     814  
     815      /**
     816       * 'ID number' from course-modules table (arbitrary text set by user) - from
     817       * course_modules table
     818       * @var string
     819       */
     820      private $idnumber;
     821  
     822      /**
     823       * Time that this course-module was added (unix time) - from course_modules table
     824       * @var int
     825       */
     826      private $added;
     827  
     828      /**
     829       * This variable is not used and is included here only so it can be documented.
     830       * Once the database entry is removed from course_modules, it should be deleted
     831       * here too.
     832       * @var int
     833       * @deprecated Do not use this variable
     834       */
     835      private $score;
     836  
     837      /**
     838       * Visible setting (0 or 1; if this is 0, students cannot see/access the activity) - from
     839       * course_modules table
     840       * @var int
     841       */
     842      private $visible;
     843  
     844      /**
     845       * Old visible setting (if the entire section is hidden, the previous value for
     846       * visible is stored in this field) - from course_modules table
     847       * @var int
     848       */
     849      private $visibleold;
     850  
     851      /**
     852       * Group mode (one of the constants NONE, SEPARATEGROUPS, or VISIBLEGROUPS) - from
     853       * course_modules table
     854       * @var int
     855       */
     856      private $groupmode;
     857  
     858      /**
     859       * Grouping ID (0 = all groupings)
     860       * @var int
     861       */
     862      private $groupingid;
     863  
     864      /**
     865       * Indent level on course page (0 = no indent) - from course_modules table
     866       * @var int
     867       */
     868      private $indent;
     869  
     870      /**
     871       * Activity completion setting for this activity, COMPLETION_TRACKING_xx constant - from
     872       * course_modules table
     873       * @var int
     874       */
     875      private $completion;
     876  
     877      /**
     878       * Set to the item number (usually 0) if completion depends on a particular
     879       * grade of this activity, or null if completion does not depend on a grade - from
     880       * course_modules table
     881       * @var mixed
     882       */
     883      private $completiongradeitemnumber;
     884  
     885      /**
     886       * 1 if 'on view' completion is enabled, 0 otherwise - from course_modules table
     887       * @var int
     888       */
     889      private $completionview;
     890  
     891      /**
     892       * Set to a unix time if completion of this activity is expected at a
     893       * particular time, 0 if no time set - from course_modules table
     894       * @var int
     895       */
     896      private $completionexpected;
     897  
     898      /**
     899       * Availability information as JSON string or null if none - from course_modules table
     900       * @var string
     901       */
     902      private $availability;
     903  
     904      /**
     905       * Controls whether the description of the activity displays on the course main page (in
     906       * addition to anywhere it might display within the activity itself). 0 = do not show
     907       * on main page, 1 = show on main page.
     908       * @var int
     909       */
     910      private $showdescription;
     911  
     912      /**
     913       * Extra HTML that is put in an unhelpful part of the HTML when displaying this module in
     914       * course page - from cached data in modinfo field
     915       * @deprecated This is crazy, don't use it. Replaced by ->extraclasses and ->onclick
     916       * @var string
     917       */
     918      private $extra;
     919  
     920      /**
     921       * Name of icon to use - from cached data in modinfo field
     922       * @var string
     923       */
     924      private $icon;
     925  
     926      /**
     927       * Component that contains icon - from cached data in modinfo field
     928       * @var string
     929       */
     930      private $iconcomponent;
     931  
     932      /**
     933       * Name of module e.g. 'forum' (this is the same name as the module's main database
     934       * table) - from cached data in modinfo field
     935       * @var string
     936       */
     937      private $modname;
     938  
     939      /**
     940       * ID of module - from course_modules table
     941       * @var int
     942       */
     943      private $module;
     944  
     945      /**
     946       * Name of module instance for display on page e.g. 'General discussion forum' - from cached
     947       * data in modinfo field
     948       * @var string
     949       */
     950      private $name;
     951  
     952      /**
     953       * Section number that this course-module is in (section 0 = above the calendar, section 1
     954       * = week/topic 1, etc) - from cached data in modinfo field
     955       * @var int
     956       */
     957      private $sectionnum;
     958  
     959      /**
     960       * Section id - from course_modules table
     961       * @var int
     962       */
     963      private $section;
     964  
     965      /**
     966       * Availability conditions for this course-module based on the completion of other
     967       * course-modules (array from other course-module id to required completion state for that
     968       * module) - from cached data in modinfo field
     969       * @var array
     970       */
     971      private $conditionscompletion;
     972  
     973      /**
     974       * Availability conditions for this course-module based on course grades (array from
     975       * grade item id to object with ->min, ->max fields) - from cached data in modinfo field
     976       * @var array
     977       */
     978      private $conditionsgrade;
     979  
     980      /**
     981       * Availability conditions for this course-module based on user fields
     982       * @var array
     983       */
     984      private $conditionsfield;
     985  
     986      /**
     987       * True if this course-module is available to students i.e. if all availability conditions
     988       * are met - obtained dynamically
     989       * @var bool
     990       */
     991      private $available;
     992  
     993      /**
     994       * If course-module is not available to students, this string gives information about
     995       * availability which can be displayed to students and/or staff (e.g. 'Available from 3
     996       * January 2010') for display on main page - obtained dynamically
     997       * @var string
     998       */
     999      private $availableinfo;
    1000  
    1001      /**
    1002       * True if this course-module is available to the CURRENT user (for example, if current user
    1003       * has viewhiddenactivities capability, they can access the course-module even if it is not
    1004       * visible or not available, so this would be true in that case)
    1005       * @var bool
    1006       */
    1007      private $uservisible;
    1008  
    1009      /**
    1010       * @var moodle_url
    1011       */
    1012      private $url;
    1013  
    1014      /**
    1015       * @var string
    1016       */
    1017      private $content;
    1018  
    1019      /**
    1020       * @var string
    1021       */
    1022      private $extraclasses;
    1023  
    1024      /**
    1025       * @var moodle_url full external url pointing to icon image for activity
    1026       */
    1027      private $iconurl;
    1028  
    1029      /**
    1030       * @var string
    1031       */
    1032      private $onclick;
    1033  
    1034      /**
    1035       * @var mixed
    1036       */
    1037      private $customdata;
    1038  
    1039      /**
    1040       * @var string
    1041       */
    1042      private $afterlink;
    1043  
    1044      /**
    1045       * @var string
    1046       */
    1047      private $afterediticons;
    1048  
    1049      /**
    1050       * List of class read-only properties and their getter methods.
    1051       * Used by magic functions __get(), __isset(), __empty()
    1052       * @var array
    1053       */
    1054      private static $standardproperties = array(
    1055          'url' => 'get_url',
    1056          'content' => 'get_content',
    1057          'extraclasses' => 'get_extra_classes',
    1058          'onclick' => 'get_on_click',
    1059          'customdata' => 'get_custom_data',
    1060          'afterlink' => 'get_after_link',
    1061          'afterediticons' => 'get_after_edit_icons',
    1062          'modfullname' => 'get_module_type_name',
    1063          'modplural' => 'get_module_type_name_plural',
    1064          'id' => false,
    1065          'added' => false,
    1066          'availability' => false,
    1067          'available' => 'get_available',
    1068          'availablefrom' => 'get_deprecated_available_date',
    1069          'availableinfo' => 'get_available_info',
    1070          'availableuntil' => 'get_deprecated_available_date',
    1071          'completion' => false,
    1072          'completionexpected' => false,
    1073          'completiongradeitemnumber' => false,
    1074          'completionview' => false,
    1075          'conditionscompletion' => false,
    1076          'conditionsfield' => false,
    1077          'conditionsgrade' => false,
    1078          'context' => 'get_context',
    1079          'course' => 'get_course_id',
    1080          'coursegroupmode' => 'get_course_groupmode',
    1081          'coursegroupmodeforce' => 'get_course_groupmodeforce',
    1082          'effectivegroupmode' => 'get_effective_groupmode',
    1083          'extra' => false,
    1084          'groupingid' => false,
    1085          'groupmembersonly' => 'get_deprecated_group_members_only',
    1086          'groupmode' => false,
    1087          'icon' => false,
    1088          'iconcomponent' => false,
    1089          'idnumber' => false,
    1090          'indent' => false,
    1091          'instance' => false,
    1092          'modname' => false,
    1093          'module' => false,
    1094          'name' => 'get_name',
    1095          'score' => false,
    1096          'section' => false,
    1097          'sectionnum' => false,
    1098          'showavailability' => 'get_show_availability',
    1099          'showdescription' => false,
    1100          'uservisible' => 'get_user_visible',
    1101          'visible' => false,
    1102          'visibleold' => false,
    1103      );
    1104  
    1105      /**
    1106       * List of methods with no arguments that were public prior to Moodle 2.6.
    1107       *
    1108       * They can still be accessed publicly via magic __call() function with no warnings
    1109       * but are not listed in the class methods list.
    1110       * For the consistency of the code it is better to use corresponding properties.
    1111       *
    1112       * These methods be deprecated completely in later versions.
    1113       *
    1114       * @var array $standardmethods
    1115       */
    1116      private static $standardmethods = array(
    1117          // Following methods are not recommended to use because there have associated read-only properties.
    1118          'get_url',
    1119          'get_content',
    1120          'get_extra_classes',
    1121          'get_on_click',
    1122          'get_custom_data',
    1123          'get_after_link',
    1124          'get_after_edit_icons',
    1125          // Method obtain_dynamic_data() should not be called from outside of this class but it was public before Moodle 2.6.
    1126          'obtain_dynamic_data',
    1127      );
    1128  
    1129      /**
    1130       * Magic method to call functions that are now declared as private now but
    1131       * were public in Moodle before 2.6. Developers can access them without
    1132       * any warnings but they are not listed in the class methods list.
    1133       *
    1134       * @param string $name
    1135       * @param array $arguments
    1136       * @return mixed
    1137       */
    1138      public function __call($name, $arguments) {
    1139          global $CFG;
    1140  
    1141          if (in_array($name, self::$standardmethods)) {
    1142              if ($CFG->debugdeveloper) {
    1143                  if ($alternative = array_search($name, self::$standardproperties)) {
    1144                      // All standard methods do not have arguments anyway.
    1145                      debugging("cm_info::$name() is deprecated, please use the property cm_info->$alternative instead.", DEBUG_DEVELOPER);
    1146                  } else {
    1147                      debugging("cm_info::$name() is deprecated and should not be used.", DEBUG_DEVELOPER);
    1148                  }
    1149              }
    1150              // All standard methods do not have arguments anyway.
    1151              return $this->$name();
    1152          }
    1153          throw new coding_exception("Method cm_info::{$name}() does not exist");
    1154      }
    1155  
    1156      /**
    1157       * Magic method getter
    1158       *
    1159       * @param string $name
    1160       * @return mixed
    1161       */
    1162      public function __get($name) {
    1163          if (isset(self::$standardproperties[$name])) {
    1164              if ($method = self::$standardproperties[$name]) {
    1165                  return $this->$method();
    1166              } else {
    1167                  return $this->$name;
    1168              }
    1169          } else {
    1170              debugging('Invalid cm_info property accessed: '.$name);
    1171              return null;
    1172          }
    1173      }
    1174  
    1175      /**
    1176       * Implementation of IteratorAggregate::getIterator(), allows to cycle through properties
    1177       * and use {@link convert_to_array()}
    1178       *
    1179       * @return ArrayIterator
    1180       */
    1181      public function getIterator() {
    1182          // Make sure dynamic properties are retrieved prior to view properties.
    1183          $this->obtain_dynamic_data();
    1184          $ret = array();
    1185  
    1186          // Do not iterate over deprecated properties.
    1187          $props = self::$standardproperties;
    1188          unset($props['showavailability']);
    1189          unset($props['availablefrom']);
    1190          unset($props['availableuntil']);
    1191          unset($props['groupmembersonly']);
    1192  
    1193          foreach ($props as $key => $unused) {
    1194              $ret[$key] = $this->__get($key);
    1195          }
    1196          return new ArrayIterator($ret);
    1197      }
    1198  
    1199      /**
    1200       * Magic method for function isset()
    1201       *
    1202       * @param string $name
    1203       * @return bool
    1204       */
    1205      public function __isset($name) {
    1206          if (isset(self::$standardproperties[$name])) {
    1207              $value = $this->__get($name);
    1208              return isset($value);
    1209          }
    1210          return false;
    1211      }
    1212  
    1213      /**
    1214       * Magic method for function empty()
    1215       *
    1216       * @param string $name
    1217       * @return bool
    1218       */
    1219      public function __empty($name) {
    1220          if (isset(self::$standardproperties[$name])) {
    1221              $value = $this->__get($name);
    1222              return empty($value);
    1223          }
    1224          return true;
    1225      }
    1226  
    1227      /**
    1228       * Magic method setter
    1229       *
    1230       * Will display the developer warning when trying to set/overwrite property.
    1231       *
    1232       * @param string $name
    1233       * @param mixed $value
    1234       */
    1235      public function __set($name, $value) {
    1236          debugging("It is not allowed to set the property cm_info::\${$name}", DEBUG_DEVELOPER);
    1237      }
    1238  
    1239      /**
    1240       * @return bool True if this module has a 'view' page that should be linked to in navigation
    1241       *   etc (note: modules may still have a view.php file, but return false if this is not
    1242       *   intended to be linked to from 'normal' parts of the interface; this is what label does).
    1243       */
    1244      public function has_view() {
    1245          return !is_null($this->url);
    1246      }
    1247  
    1248      /**
    1249       * @return moodle_url URL to link to for this module, or null if it doesn't have a view page
    1250       */
    1251      private function get_url() {
    1252          $this->obtain_dynamic_data();
    1253          return $this->url;
    1254      }
    1255  
    1256      /**
    1257       * Obtains content to display on main (view) page.
    1258       * Note: Will collect view data, if not already obtained.
    1259       * @return string Content to display on main page below link, or empty string if none
    1260       */
    1261      private function get_content() {
    1262          $this->obtain_view_data();
    1263          return $this->content;
    1264      }
    1265  
    1266      /**
    1267       * Returns the content to display on course/overview page, formatted and passed through filters
    1268       *
    1269       * if $options['context'] is not specified, the module context is used
    1270       *
    1271       * @param array|stdClass $options formatting options, see {@link format_text()}
    1272       * @return string
    1273       */
    1274      public function get_formatted_content($options = array()) {
    1275          $this->obtain_view_data();
    1276          if (empty($this->content)) {
    1277              return '';
    1278          }
    1279          // Improve filter performance by preloading filter setttings for all
    1280          // activities on the course (this does nothing if called multiple
    1281          // times)
    1282          filter_preload_activities($this->get_modinfo());
    1283  
    1284          $options = (array)$options;
    1285          if (!isset($options['context'])) {
    1286              $options['context'] = $this->get_context();
    1287          }
    1288          return format_text($this->content, FORMAT_HTML, $options);
    1289      }
    1290  
    1291      /**
    1292       * Getter method for property $name, ensures that dynamic data is obtained.
    1293       * @return string
    1294       */
    1295      private function get_name() {
    1296          $this->obtain_dynamic_data();
    1297          return $this->name;
    1298      }
    1299  
    1300      /**
    1301       * Returns the name to display on course/overview page, formatted and passed through filters
    1302       *
    1303       * if $options['context'] is not specified, the module context is used
    1304       *
    1305       * @param array|stdClass $options formatting options, see {@link format_string()}
    1306       * @return string
    1307       */
    1308      public function get_formatted_name($options = array()) {
    1309          global $CFG;
    1310          $options = (array)$options;
    1311          if (!isset($options['context'])) {
    1312              $options['context'] = $this->get_context();
    1313          }
    1314          // Improve filter performance by preloading filter setttings for all
    1315          // activities on the course (this does nothing if called multiple
    1316          // times).
    1317          if (!empty($CFG->filterall)) {
    1318              filter_preload_activities($this->get_modinfo());
    1319          }
    1320          return format_string($this->get_name(), true,  $options);
    1321      }
    1322  
    1323      /**
    1324       * Note: Will collect view data, if not already obtained.
    1325       * @return string Extra CSS classes to add to html output for this activity on main page
    1326       */
    1327      private function get_extra_classes() {
    1328          $this->obtain_view_data();
    1329          return $this->extraclasses;
    1330      }
    1331  
    1332      /**
    1333       * @return string Content of HTML on-click attribute. This string will be used literally
    1334       * as a string so should be pre-escaped.
    1335       */
    1336      private function get_on_click() {
    1337          // Does not need view data; may be used by navigation
    1338          $this->obtain_dynamic_data();
    1339          return $this->onclick;
    1340      }
    1341      /**
    1342       * @return mixed Optional custom data stored in modinfo cache for this activity, or null if none
    1343       */
    1344      private function get_custom_data() {
    1345          return $this->customdata;
    1346      }
    1347  
    1348      /**
    1349       * Note: Will collect view data, if not already obtained.
    1350       * @return string Extra HTML code to display after link
    1351       */
    1352      private function get_after_link() {
    1353          $this->obtain_view_data();
    1354          return $this->afterlink;
    1355      }
    1356  
    1357      /**
    1358       * Note: Will collect view data, if not already obtained.
    1359       * @return string Extra HTML code to display after editing icons (e.g. more icons)
    1360       */
    1361      private function get_after_edit_icons() {
    1362          $this->obtain_view_data();
    1363          return $this->afterediticons;
    1364      }
    1365  
    1366      /**
    1367       * @param moodle_core_renderer $output Output render to use, or null for default (global)
    1368       * @return moodle_url Icon URL for a suitable icon to put beside this cm
    1369       */
    1370      public function get_icon_url($output = null) {
    1371          global $OUTPUT;
    1372          $this->obtain_dynamic_data();
    1373          if (!$output) {
    1374              $output = $OUTPUT;
    1375          }
    1376          // Support modules setting their own, external, icon image
    1377          if (!empty($this->iconurl)) {
    1378              $icon = $this->iconurl;
    1379  
    1380          // Fallback to normal local icon + component procesing
    1381          } else if (!empty($this->icon)) {
    1382              if (substr($this->icon, 0, 4) === 'mod/') {
    1383                  list($modname, $iconname) = explode('/', substr($this->icon, 4), 2);
    1384                  $icon = $output->pix_url($iconname, $modname);
    1385              } else {
    1386                  if (!empty($this->iconcomponent)) {
    1387                      // Icon  has specified component
    1388                      $icon = $output->pix_url($this->icon, $this->iconcomponent);
    1389                  } else {
    1390                      // Icon does not have specified component, use default
    1391                      $icon = $output->pix_url($this->icon);
    1392                  }
    1393              }
    1394          } else {
    1395              $icon = $output->pix_url('icon', $this->modname);
    1396          }
    1397          return $icon;
    1398      }
    1399  
    1400      /**
    1401       * @param string $textclasses additionnal classes for grouping label
    1402       * @return string An empty string or HTML grouping label span tag
    1403       */
    1404      public function get_grouping_label($textclasses = '') {
    1405          $groupinglabel = '';
    1406          if (!empty($this->groupingid) && has_capability('moodle/course:managegroups', context_course::instance($this->course))) {
    1407              $groupings = groups_get_all_groupings($this->course);
    1408              $groupinglabel = html_writer::tag('span', '('.format_string($groupings[$this->groupingid]->name).')',
    1409                  array('class' => 'groupinglabel '.$textclasses));
    1410          }
    1411          return $groupinglabel;
    1412      }
    1413  
    1414      /**
    1415       * Returns a localised human-readable name of the module type
    1416       *
    1417       * @param bool $plural return plural form
    1418       * @return string
    1419       */
    1420      public function get_module_type_name($plural = false) {
    1421          $modnames = get_module_types_names($plural);
    1422          if (isset($modnames[$this->modname])) {
    1423              return $modnames[$this->modname];
    1424          } else {
    1425              return null;
    1426          }
    1427      }
    1428  
    1429      /**
    1430       * Returns a localised human-readable name of the module type in plural form - calculated on request
    1431       *
    1432       * @return string
    1433       */
    1434      private function get_module_type_name_plural() {
    1435          return $this->get_module_type_name(true);
    1436      }
    1437  
    1438      /**
    1439       * @return course_modinfo Modinfo object that this came from
    1440       */
    1441      public function get_modinfo() {
    1442          return $this->modinfo;
    1443      }
    1444  
    1445      /**
    1446       * Returns course object that was used in the first {@link get_fast_modinfo()} call.
    1447       *
    1448       * It may not contain all fields from DB table {course} but always has at least the following:
    1449       * id,shortname,fullname,format,enablecompletion,groupmode,groupmodeforce,cacherev
    1450       *
    1451       * If the course object lacks the field you need you can use the global
    1452       * function {@link get_course()} that will save extra query if you access
    1453       * current course or frontpage course.
    1454       *
    1455       * @return stdClass
    1456       */
    1457      public function get_course() {
    1458          return $this->modinfo->get_course();
    1459      }
    1460  
    1461      /**
    1462       * Returns course id for which the modinfo was generated.
    1463       *
    1464       * @return int
    1465       */
    1466      private function get_course_id() {
    1467          return $this->modinfo->get_course_id();
    1468      }
    1469  
    1470      /**
    1471       * Returns group mode used for the course containing the module
    1472       *
    1473       * @return int one of constants NOGROUPS, SEPARATEGROUPS, VISIBLEGROUPS
    1474       */
    1475      private function get_course_groupmode() {
    1476          return $this->modinfo->get_course()->groupmode;
    1477      }
    1478  
    1479      /**
    1480       * Returns whether group mode is forced for the course containing the module
    1481       *
    1482       * @return bool
    1483       */
    1484      private function get_course_groupmodeforce() {
    1485          return $this->modinfo->get_course()->groupmodeforce;
    1486      }
    1487  
    1488      /**
    1489       * Returns effective groupmode of the module that may be overwritten by forced course groupmode.
    1490       *
    1491       * @return int one of constants NOGROUPS, SEPARATEGROUPS, VISIBLEGROUPS
    1492       */
    1493      private function get_effective_groupmode() {
    1494          $groupmode = $this->groupmode;
    1495          if ($this->modinfo->get_course()->groupmodeforce) {
    1496              $groupmode = $this->modinfo->get_course()->groupmode;
    1497              if ($groupmode != NOGROUPS && !plugin_supports('mod', $this->modname, FEATURE_GROUPS, 0)) {
    1498                  $groupmode = NOGROUPS;
    1499              }
    1500          }
    1501          return $groupmode;
    1502      }
    1503  
    1504      /**
    1505       * @return context_module Current module context
    1506       */
    1507      private function get_context() {
    1508          return context_module::instance($this->id);
    1509      }
    1510  
    1511      /**
    1512       * Returns itself in the form of stdClass.
    1513       *
    1514       * The object includes all fields that table course_modules has and additionally
    1515       * fields 'name', 'modname', 'sectionnum' (if requested).
    1516       *
    1517       * This can be used as a faster alternative to {@link get_coursemodule_from_id()}
    1518       *
    1519       * @param bool $additionalfields include additional fields 'name', 'modname', 'sectionnum'
    1520       * @return stdClass
    1521       */
    1522      public function get_course_module_record($additionalfields = false) {
    1523          $cmrecord = new stdClass();
    1524  
    1525          // Standard fields from table course_modules.
    1526          static $cmfields = array('id', 'course', 'module', 'instance', 'section', 'idnumber', 'added',
    1527              'score', 'indent', 'visible', 'visibleold', 'groupmode', 'groupingid',
    1528              'completion', 'completiongradeitemnumber', 'completionview', 'completionexpected',
    1529              'showdescription', 'availability');
    1530          foreach ($cmfields as $key) {
    1531              $cmrecord->$key = $this->$key;
    1532          }
    1533  
    1534          // Additional fields that function get_coursemodule_from_id() adds.
    1535          if ($additionalfields) {
    1536              $cmrecord->name = $this->name;
    1537              $cmrecord->modname = $this->modname;
    1538              $cmrecord->sectionnum = $this->sectionnum;
    1539          }
    1540  
    1541          return $cmrecord;
    1542      }
    1543  
    1544      // Set functions
    1545      ////////////////
    1546  
    1547      /**
    1548       * Sets content to display on course view page below link (if present).
    1549       * @param string $content New content as HTML string (empty string if none)
    1550       * @return void
    1551       */
    1552      public function set_content($content) {
    1553          $this->content = $content;
    1554      }
    1555  
    1556      /**
    1557       * Sets extra classes to include in CSS.
    1558       * @param string $extraclasses Extra classes (empty string if none)
    1559       * @return void
    1560       */
    1561      public function set_extra_classes($extraclasses) {
    1562          $this->extraclasses = $extraclasses;
    1563      }
    1564  
    1565      /**
    1566       * Sets the external full url that points to the icon being used
    1567       * by the activity. Useful for external-tool modules (lti...)
    1568       * If set, takes precedence over $icon and $iconcomponent
    1569       *
    1570       * @param moodle_url $iconurl full external url pointing to icon image for activity
    1571       * @return void
    1572       */
    1573      public function set_icon_url(moodle_url $iconurl) {
    1574          $this->iconurl = $iconurl;
    1575      }
    1576  
    1577      /**
    1578       * Sets value of on-click attribute for JavaScript.
    1579       * Note: May not be called from _cm_info_view (only _cm_info_dynamic).
    1580       * @param string $onclick New onclick attribute which should be HTML-escaped
    1581       *   (empty string if none)
    1582       * @return void
    1583       */
    1584      public function set_on_click($onclick) {
    1585          $this->check_not_view_only();
    1586          $this->onclick = $onclick;
    1587      }
    1588  
    1589      /**
    1590       * Sets HTML that displays after link on course view page.
    1591       * @param string $afterlink HTML string (empty string if none)
    1592       * @return void
    1593       */
    1594      public function set_after_link($afterlink) {
    1595          $this->afterlink = $afterlink;
    1596      }
    1597  
    1598      /**
    1599       * Sets HTML that displays after edit icons on course view page.
    1600       * @param string $afterediticons HTML string (empty string if none)
    1601       * @return void
    1602       */
    1603      public function set_after_edit_icons($afterediticons) {
    1604          $this->afterediticons = $afterediticons;
    1605      }
    1606  
    1607      /**
    1608       * Changes the name (text of link) for this module instance.
    1609       * Note: May not be called from _cm_info_view (only _cm_info_dynamic).
    1610       * @param string $name Name of activity / link text
    1611       * @return void
    1612       */
    1613      public function set_name($name) {
    1614          if ($this->state < self::STATE_BUILDING_DYNAMIC) {
    1615              $this->update_user_visible();
    1616          }
    1617          $this->name = $name;
    1618      }
    1619  
    1620      /**
    1621       * Turns off the view link for this module instance.
    1622       * Note: May not be called from _cm_info_view (only _cm_info_dynamic).
    1623       * @return void
    1624       */
    1625      public function set_no_view_link() {
    1626          $this->check_not_view_only();
    1627          $this->url = null;
    1628      }
    1629  
    1630      /**
    1631       * Sets the 'uservisible' flag. This can be used (by setting false) to prevent access and
    1632       * display of this module link for the current user.
    1633       * Note: May not be called from _cm_info_view (only _cm_info_dynamic).
    1634       * @param bool $uservisible
    1635       * @return void
    1636       */
    1637      public function set_user_visible($uservisible) {
    1638          $this->check_not_view_only();
    1639          $this->uservisible = $uservisible;
    1640      }
    1641  
    1642      /**
    1643       * Sets the 'available' flag and related details. This flag is normally used to make
    1644       * course modules unavailable until a certain date or condition is met. (When a course
    1645       * module is unavailable, it is still visible to users who have viewhiddenactivities
    1646       * permission.)
    1647       *
    1648       * When this is function is called, user-visible status is recalculated automatically.
    1649       *
    1650       * The $showavailability flag does not really do anything any more, but is retained
    1651       * for backward compatibility. Setting this to false will cause $availableinfo to
    1652       * be ignored.
    1653       *
    1654       * Note: May not be called from _cm_info_view (only _cm_info_dynamic).
    1655       * @param bool $available False if this item is not 'available'
    1656       * @param int $showavailability 0 = do not show this item at all if it's not available,
    1657       *   1 = show this item greyed out with the following message
    1658       * @param string $availableinfo Information about why this is not available, or
    1659       *   empty string if not displaying
    1660       * @return void
    1661       */
    1662      public function set_available($available, $showavailability=0, $availableinfo='') {
    1663          $this->check_not_view_only();
    1664          $this->available = $available;
    1665          if (!$showavailability) {
    1666              $availableinfo = '';
    1667          }
    1668          $this->availableinfo = $availableinfo;
    1669          $this->update_user_visible();
    1670      }
    1671  
    1672      /**
    1673       * Some set functions can only be called from _cm_info_dynamic and not _cm_info_view.
    1674       * This is because they may affect parts of this object which are used on pages other
    1675       * than the view page (e.g. in the navigation block, or when checking access on
    1676       * module pages).
    1677       * @return void
    1678       */
    1679      private function check_not_view_only() {
    1680          if ($this->state >= self::STATE_DYNAMIC) {
    1681              throw new coding_exception('Cannot set this data from _cm_info_view because it may ' .
    1682                      'affect other pages as well as view');
    1683          }
    1684      }
    1685  
    1686      /**
    1687       * Constructor should not be called directly; use {@link get_fast_modinfo()}
    1688       *
    1689       * @param course_modinfo $modinfo Parent object
    1690       * @param stdClass $notused1 Argument not used
    1691       * @param stdClass $mod Module object from the modinfo field of course table
    1692       * @param stdClass $notused2 Argument not used
    1693       */
    1694      public function __construct(course_modinfo $modinfo, $notused1, $mod, $notused2) {
    1695          $this->modinfo = $modinfo;
    1696  
    1697          $this->id               = $mod->cm;
    1698          $this->instance         = $mod->id;
    1699          $this->modname          = $mod->mod;
    1700          $this->idnumber         = isset($mod->idnumber) ? $mod->idnumber : '';
    1701          $this->name             = $mod->name;
    1702          $this->visible          = $mod->visible;
    1703          $this->sectionnum       = $mod->section; // Note weirdness with name here
    1704          $this->groupmode        = isset($mod->groupmode) ? $mod->groupmode : 0;
    1705          $this->groupingid       = isset($mod->groupingid) ? $mod->groupingid : 0;
    1706          $this->indent           = isset($mod->indent) ? $mod->indent : 0;
    1707          $this->extra            = isset($mod->extra) ? $mod->extra : '';
    1708          $this->extraclasses     = isset($mod->extraclasses) ? $mod->extraclasses : '';
    1709          // iconurl may be stored as either string or instance of moodle_url.
    1710          $this->iconurl          = isset($mod->iconurl) ? new moodle_url($mod->iconurl) : '';
    1711          $this->onclick          = isset($mod->onclick) ? $mod->onclick : '';
    1712          $this->content          = isset($mod->content) ? $mod->content : '';
    1713          $this->icon             = isset($mod->icon) ? $mod->icon : '';
    1714          $this->iconcomponent    = isset($mod->iconcomponent) ? $mod->iconcomponent : '';
    1715          $this->customdata       = isset($mod->customdata) ? $mod->customdata : '';
    1716          $this->showdescription  = isset($mod->showdescription) ? $mod->showdescription : 0;
    1717          $this->state = self::STATE_BASIC;
    1718  
    1719          $this->section = isset($mod->sectionid) ? $mod->sectionid : 0;
    1720          $this->module = isset($mod->module) ? $mod->module : 0;
    1721          $this->added = isset($mod->added) ? $mod->added : 0;
    1722          $this->score = isset($mod->score) ? $mod->score : 0;
    1723          $this->visibleold = isset($mod->visibleold) ? $mod->visibleold : 0;
    1724  
    1725          // Note: it saves effort and database space to always include the
    1726          // availability and completion fields, even if availability or completion
    1727          // are actually disabled
    1728          $this->completion = isset($mod->completion) ? $mod->completion : 0;
    1729          $this->completiongradeitemnumber = isset($mod->completiongradeitemnumber)
    1730                  ? $mod->completiongradeitemnumber : null;
    1731          $this->completionview = isset($mod->completionview)
    1732                  ? $mod->completionview : 0;
    1733          $this->completionexpected = isset($mod->completionexpected)
    1734                  ? $mod->completionexpected : 0;
    1735          $this->availability = isset($mod->availability) ? $mod->availability : null;
    1736          $this->conditionscompletion = isset($mod->conditionscompletion)
    1737                  ? $mod->conditionscompletion : array();
    1738          $this->conditionsgrade = isset($mod->conditionsgrade)
    1739                  ? $mod->conditionsgrade : array();
    1740          $this->conditionsfield = isset($mod->conditionsfield)
    1741                  ? $mod->conditionsfield : array();
    1742  
    1743          static $modviews = array();
    1744          if (!isset($modviews[$this->modname])) {
    1745              $modviews[$this->modname] = !plugin_supports('mod', $this->modname,
    1746                      FEATURE_NO_VIEW_LINK);
    1747          }
    1748          $this->url = $modviews[$this->modname]
    1749                  ? new moodle_url('/mod/' . $this->modname . '/view.php', array('id'=>$this->id))
    1750                  : null;
    1751      }
    1752  
    1753      /**
    1754       * Creates a cm_info object from a database record (also accepts cm_info
    1755       * in which case it is just returned unchanged).
    1756       *
    1757       * @param stdClass|cm_info|null|bool $cm Stdclass or cm_info (or null or false)
    1758       * @param int $userid Optional userid (default to current)
    1759       * @return cm_info|null Object as cm_info, or null if input was null/false
    1760       */
    1761      public static function create($cm, $userid = 0) {
    1762          // Null, false, etc. gets passed through as null.
    1763          if (!$cm) {
    1764              return null;
    1765          }
    1766          // If it is already a cm_info object, just return it.
    1767          if ($cm instanceof cm_info) {
    1768              return $cm;
    1769          }
    1770          // Otherwise load modinfo.
    1771          if (empty($cm->id) || empty($cm->course)) {
    1772              throw new coding_exception('$cm must contain ->id and ->course');
    1773          }
    1774          $modinfo = get_fast_modinfo($cm->course, $userid);
    1775          return $modinfo->get_cm($cm->id);
    1776      }
    1777  
    1778      /**
    1779       * If dynamic data for this course-module is not yet available, gets it.
    1780       *
    1781       * This function is automatically called when requesting any course_modinfo property
    1782       * that can be modified by modules (have a set_xxx method).
    1783       *
    1784       * Dynamic data is data which does not come directly from the cache but is calculated at
    1785       * runtime based on the current user. Primarily this concerns whether the user can access
    1786       * the module or not.
    1787       *
    1788       * As part of this function, the module's _cm_info_dynamic function from its lib.php will
    1789       * be called (if it exists).
    1790       * @return void
    1791       */
    1792      private function obtain_dynamic_data() {
    1793          global $CFG;
    1794          $userid = $this->modinfo->get_user_id();
    1795          if ($this->state >= self::STATE_BUILDING_DYNAMIC || $userid == -1) {
    1796              return;
    1797          }
    1798          $this->state = self::STATE_BUILDING_DYNAMIC;
    1799  
    1800          if (!empty($CFG->enableavailability)) {
    1801              require_once($CFG->libdir. '/conditionlib.php');
    1802              // Get availability information.
    1803              $ci = new \core_availability\info_module($this);
    1804  
    1805              // Note that the modinfo currently available only includes minimal details (basic data)
    1806              // but we know that this function does not need anything more than basic data.
    1807              $this->available = $ci->is_available($this->availableinfo, true,
    1808                      $userid, $this->modinfo);
    1809          } else {
    1810              $this->available = true;
    1811          }
    1812  
    1813          // Check parent section.
    1814          if ($this->available) {
    1815              $parentsection = $this->modinfo->get_section_info($this->sectionnum);
    1816              if (!$parentsection->available) {
    1817                  // Do not store info from section here, as that is already
    1818                  // presented from the section (if appropriate) - just change
    1819                  // the flag
    1820                  $this->available = false;
    1821              }
    1822          }
    1823  
    1824          // Update visible state for current user.
    1825          $this->update_user_visible();
    1826  
    1827          // Let module make dynamic changes at this point
    1828          $this->call_mod_function('cm_info_dynamic');
    1829          $this->state = self::STATE_DYNAMIC;
    1830      }
    1831  
    1832      /**
    1833       * Getter method for property $uservisible, ensures that dynamic data is retrieved.
    1834       * @return bool
    1835       */
    1836      private function get_user_visible() {
    1837          $this->obtain_dynamic_data();
    1838          return $this->uservisible;
    1839      }
    1840  
    1841      /**
    1842       * Getter method for property $available, ensures that dynamic data is retrieved
    1843       * @return bool
    1844       */
    1845      private function get_available() {
    1846          $this->obtain_dynamic_data();
    1847          return $this->available;
    1848      }
    1849  
    1850      /**
    1851       * Getter method for property $showavailability. Works by checking the
    1852       * availableinfo property to see if it's empty or not.
    1853       *
    1854       * @return int
    1855       * @deprecated Since Moodle 2.7
    1856       */
    1857      private function get_show_availability() {
    1858          debugging('$cm->showavailability property has been deprecated. You ' .
    1859                  'can replace it by checking if $cm->availableinfo has content.',
    1860                  DEBUG_DEVELOPER);
    1861          return ($this->get_available_info() !== '') ? 1 : 0;
    1862      }
    1863  
    1864      /**
    1865       * Getter method for $availablefrom and $availableuntil. Just returns zero
    1866       * as these are no longer supported.
    1867       *
    1868       * @return int Zero
    1869       * @deprecated Since Moodle 2.7
    1870       */
    1871      private function get_deprecated_available_date() {
    1872          debugging('$cm->availablefrom and $cm->availableuntil have been deprecated. This ' .
    1873                  'information is no longer available as the system provides more complex ' .
    1874                  'options (for example, there might be different dates for different users).',
    1875                  DEBUG_DEVELOPER);
    1876          return 0;
    1877      }
    1878  
    1879      /**
    1880       * Getter method for $availablefrom and $availableuntil. Just returns zero
    1881       * as these are no longer supported.
    1882       *
    1883       * @return int Zero
    1884       * @deprecated Since Moodle 2.8
    1885       */
    1886      private function get_deprecated_group_members_only() {
    1887          debugging('$cm->groupmembersonly has been deprecated and always returns zero. ' .
    1888                  'If used to restrict a list of enrolled users to only those who can ' .
    1889                  'access the module, consider \core_availability\info_module::filter_user_list.',
    1890                  DEBUG_DEVELOPER);
    1891          return 0;
    1892      }
    1893  
    1894      /**
    1895       * Getter method for property $availableinfo, ensures that dynamic data is retrieved
    1896       *
    1897       * @return string Available info (HTML)
    1898       */
    1899      private function get_available_info() {
    1900          $this->obtain_dynamic_data();
    1901          return $this->availableinfo;
    1902      }
    1903  
    1904      /**
    1905       * Works out whether activity is available to the current user
    1906       *
    1907       * If the activity is unavailable, additional checks are required to determine if its hidden or greyed out
    1908       *
    1909       * @see is_user_access_restricted_by_conditional_access()
    1910       * @return void
    1911       */
    1912      private function update_user_visible() {
    1913          $userid = $this->modinfo->get_user_id();
    1914          if ($userid == -1) {
    1915              return null;
    1916          }
    1917          $this->uservisible = true;
    1918  
    1919          // If the user cannot access the activity set the uservisible flag to false.
    1920          // Additional checks are required to determine whether the activity is entirely hidden or just greyed out.
    1921          if ((!$this->visible or !$this->get_available()) and
    1922                  !has_capability('moodle/course:viewhiddenactivities', $this->get_context(), $userid)) {
    1923  
    1924              $this->uservisible = false;
    1925          }
    1926  
    1927          // Check group membership.
    1928          if ($this->is_user_access_restricted_by_capability()) {
    1929  
    1930               $this->uservisible = false;
    1931              // Ensure activity is completely hidden from the user.
    1932              $this->availableinfo = '';
    1933          }
    1934      }
    1935  
    1936      /**
    1937       * Checks whether the module's group settings restrict the current user's
    1938       * access. This function is not necessary now that all access restrictions
    1939       * are handled by the availability API. You can use $cm->uservisible to
    1940       * find out if the current user can access an activity, or $cm->availableinfo
    1941       * to get information about why not.
    1942       *
    1943       * @return bool False
    1944       * @deprecated Since Moodle 2.8
    1945       */
    1946      public function is_user_access_restricted_by_group() {
    1947          debugging('cm_info::is_user_access_restricted_by_group() ' .
    1948                  'is deprecated and always returns false; use $cm->uservisible ' .
    1949                  'to decide whether the current user can access an activity', DEBUG_DEVELOPER);
    1950          return false;
    1951      }
    1952  
    1953      /**
    1954       * Checks whether mod/...:view capability restricts the current user's access.
    1955       *
    1956       * @return bool True if the user access is restricted.
    1957       */
    1958      public function is_user_access_restricted_by_capability() {
    1959          $userid = $this->modinfo->get_user_id();
    1960          if ($userid == -1) {
    1961              return null;
    1962          }
    1963          $capability = 'mod/' . $this->modname . ':view';
    1964          $capabilityinfo = get_capability_info($capability);
    1965          if (!$capabilityinfo) {
    1966              // Capability does not exist, no one is prevented from seeing the activity.
    1967              return false;
    1968          }
    1969  
    1970          // You are blocked if you don't have the capability.
    1971          return !has_capability($capability, $this->get_context(), $userid);
    1972      }
    1973  
    1974      /**
    1975       * Checks whether the module's conditional access settings mean that the
    1976       * user cannot see the activity at all
    1977       *
    1978       * This is deprecated because it is confusing (name sounds like it's about
    1979       * access restriction but it is actually about display), is not used
    1980       * anywhere, and is not necessary. Nobody (outside conditional libraries)
    1981       * should care what it is that restricted something.
    1982       *
    1983       * @return bool True if the user cannot see the module. False if the activity is either available or should be greyed out.
    1984       * @deprecated since 2.7
    1985       */
    1986      public function is_user_access_restricted_by_conditional_access() {
    1987          global $CFG;
    1988          debugging('cm_info::is_user_access_restricted_by_conditional_access() ' .
    1989                  'is deprecated; this function is not needed (use $cm->uservisible ' .
    1990                  'and $cm->availableinfo to decide whether it should be available ' .
    1991                  'or appear)', DEBUG_DEVELOPER);
    1992  
    1993          if (empty($CFG->enableavailability)) {
    1994              return false;
    1995          }
    1996  
    1997          $userid = $this->modinfo->get_user_id();
    1998          if ($userid == -1) {
    1999              return null;
    2000          }
    2001  
    2002          // Return false if user can access the activity, or if its availability
    2003          // info is set (= should be displayed even though not accessible).
    2004          return !$this->get_user_visible() && !$this->get_available_info();
    2005      }
    2006  
    2007      /**
    2008       * Calls a module function (if exists), passing in one parameter: this object.
    2009       * @param string $type Name of function e.g. if this is 'grooblezorb' and the modname is
    2010       *   'forum' then it will try to call 'mod_forum_grooblezorb' or 'forum_grooblezorb'
    2011       * @return void
    2012       */
    2013      private function call_mod_function($type) {
    2014          global $CFG;
    2015          $libfile = $CFG->dirroot . '/mod/' . $this->modname . '/lib.php';
    2016          if (file_exists($libfile)) {
    2017              include_once($libfile);
    2018              $function = 'mod_' . $this->modname . '_' . $type;
    2019              if (function_exists($function)) {
    2020                  $function($this);
    2021              } else {
    2022                  $function = $this->modname . '_' . $type;
    2023                  if (function_exists($function)) {
    2024                      $function($this);
    2025                  }
    2026              }
    2027          }
    2028      }
    2029  
    2030      /**
    2031       * If view data for this course-module is not yet available, obtains it.
    2032       *
    2033       * This function is automatically called if any of the functions (marked) which require
    2034       * view data are called.
    2035       *
    2036       * View data is data which is needed only for displaying the course main page (& any similar
    2037       * functionality on other pages) but is not needed in general. Obtaining view data may have
    2038       * a performance cost.
    2039       *
    2040       * As part of this function, the module's _cm_info_view function from its lib.php will
    2041       * be called (if it exists).
    2042       * @return void
    2043       */
    2044      private function obtain_view_data() {
    2045          if ($this->state >= self::STATE_BUILDING_VIEW || $this->modinfo->get_user_id() == -1) {
    2046              return;
    2047          }
    2048          $this->obtain_dynamic_data();
    2049          $this->state = self::STATE_BUILDING_VIEW;
    2050  
    2051          // Let module make changes at this point
    2052          $this->call_mod_function('cm_info_view');
    2053          $this->state = self::STATE_VIEW;
    2054      }
    2055  }
    2056  
    2057  
    2058  /**
    2059   * Returns reference to full info about modules in course (including visibility).
    2060   * Cached and as fast as possible (0 or 1 db query).
    2061   *
    2062   * use get_fast_modinfo($courseid, 0, true) to reset the static cache for particular course
    2063   * use get_fast_modinfo(0, 0, true) to reset the static cache for all courses
    2064   *
    2065   * use rebuild_course_cache($courseid, true) to reset the application AND static cache
    2066   * for particular course when it's contents has changed
    2067   *
    2068   * @param int|stdClass $courseorid object from DB table 'course' (must have field 'id'
    2069   *     and recommended to have field 'cacherev') or just a course id. Just course id
    2070   *     is enough when calling get_fast_modinfo() for current course or site or when
    2071   *     calling for any other course for the second time.
    2072   * @param int $userid User id to populate 'availble' and 'uservisible' attributes of modules and sections.
    2073   *     Set to 0 for current user (default). Set to -1 to avoid calculation of dynamic user-depended data.
    2074   * @param bool $resetonly whether we want to get modinfo or just reset the cache
    2075   * @return course_modinfo|null Module information for course, or null if resetting
    2076   * @throws moodle_exception when course is not found (nothing is thrown if resetting)
    2077   */
    2078  function get_fast_modinfo($courseorid, $userid = 0, $resetonly = false) {
    2079      // compartibility with syntax prior to 2.4:
    2080      if ($courseorid === 'reset') {
    2081          debugging("Using the string 'reset' as the first argument of get_fast_modinfo() is deprecated. Use get_fast_modinfo(0,0,true) instead.", DEBUG_DEVELOPER);
    2082          $courseorid = 0;
    2083          $resetonly = true;
    2084      }
    2085  
    2086      // Function get_fast_modinfo() can never be called during upgrade unless it is used for clearing cache only.
    2087      if (!$resetonly) {
    2088          upgrade_ensure_not_running();
    2089      }
    2090  
    2091      // Function is called with $reset = true
    2092      if ($resetonly) {
    2093          course_modinfo::clear_instance_cache($courseorid);
    2094          return null;
    2095      }
    2096  
    2097      // Function is called with $reset = false, retrieve modinfo
    2098      return course_modinfo::instance($courseorid, $userid);
    2099  }
    2100  
    2101  /**
    2102   * Efficiently retrieves the $course (stdclass) and $cm (cm_info) objects, given
    2103   * a cmid. If module name is also provided, it will ensure the cm is of that type.
    2104   *
    2105   * Usage:
    2106   * list($course, $cm) = get_course_and_cm_from_cmid($cmid, 'forum');
    2107   *
    2108   * Using this method has a performance advantage because it works by loading
    2109   * modinfo for the course - which will then be cached and it is needed later
    2110   * in most requests. It also guarantees that the $cm object is a cm_info and
    2111   * not a stdclass.
    2112   *
    2113   * The $course object can be supplied if already known and will speed
    2114   * up this function - although it is more efficient to use this function to
    2115   * get the course if you are starting from a cmid.
    2116   *
    2117   * To avoid security problems and obscure bugs, you should always specify
    2118   * $modulename if the cmid value came from user input.
    2119   *
    2120   * By default this obtains information (for example, whether user can access
    2121   * the activity) for current user, but you can specify a userid if required.
    2122   *
    2123   * @param stdClass|int $cmorid Id of course-module, or database object
    2124   * @param string $modulename Optional modulename (improves security)
    2125   * @param stdClass|int $courseorid Optional course object if already loaded
    2126   * @param int $userid Optional userid (default = current)
    2127   * @return array Array with 2 elements $course and $cm
    2128   * @throws moodle_exception If the item doesn't exist or is of wrong module name
    2129   */
    2130  function get_course_and_cm_from_cmid($cmorid, $modulename = '', $courseorid = 0, $userid = 0) {
    2131      global $DB;
    2132      if (is_object($cmorid)) {
    2133          $cmid = $cmorid->id;
    2134          if (isset($cmorid->course)) {
    2135              $courseid = (int)$cmorid->course;
    2136          } else {
    2137              $courseid = 0;
    2138          }
    2139      } else {
    2140          $cmid = (int)$cmorid;
    2141          $courseid = 0;
    2142      }
    2143  
    2144      // Validate module name if supplied.
    2145      if ($modulename && !core_component::is_valid_plugin_name('mod', $modulename)) {
    2146          throw new coding_exception('Invalid modulename parameter');
    2147      }
    2148  
    2149      // Get course from last parameter if supplied.
    2150      $course = null;
    2151      if (is_object($courseorid)) {
    2152          $course = $courseorid;
    2153      } else if ($courseorid) {
    2154          $courseid = (int)$courseorid;
    2155      }
    2156  
    2157      if (!$course) {
    2158          if ($courseid) {
    2159              // If course ID is known, get it using normal function.
    2160              $course = get_course($courseid);
    2161          } else {
    2162              // Get course record in a single query based on cmid.
    2163              $course = $DB->get_record_sql("
    2164                      SELECT c.*
    2165                        FROM {course_modules} cm
    2166                        JOIN {course} c ON c.id = cm.course
    2167                       WHERE cm.id = ?", array($cmid), MUST_EXIST);
    2168          }
    2169      }
    2170  
    2171      // Get cm from get_fast_modinfo.
    2172      $modinfo = get_fast_modinfo($course, $userid);
    2173      $cm = $modinfo->get_cm($cmid);
    2174      if ($modulename && $cm->modname !== $modulename) {
    2175          throw new moodle_exception('invalidcoursemodule', 'error');
    2176      }
    2177      return array($course, $cm);
    2178  }
    2179  
    2180  /**
    2181   * Efficiently retrieves the $course (stdclass) and $cm (cm_info) objects, given
    2182   * an instance id or record and module name.
    2183   *
    2184   * Usage:
    2185   * list($course, $cm) = get_course_and_cm_from_instance($forum, 'forum');
    2186   *
    2187   * Using this method has a performance advantage because it works by loading
    2188   * modinfo for the course - which will then be cached and it is needed later
    2189   * in most requests. It also guarantees that the $cm object is a cm_info and
    2190   * not a stdclass.
    2191   *
    2192   * The $course object can be supplied if already known and will speed
    2193   * up this function - although it is more efficient to use this function to
    2194   * get the course if you are starting from an instance id.
    2195   *
    2196   * By default this obtains information (for example, whether user can access
    2197   * the activity) for current user, but you can specify a userid if required.
    2198   *
    2199   * @param stdclass|int $instanceorid Id of module instance, or database object
    2200   * @param string $modulename Modulename (required)
    2201   * @param stdClass|int $courseorid Optional course object if already loaded
    2202   * @param int $userid Optional userid (default = current)
    2203   * @return array Array with 2 elements $course and $cm
    2204   * @throws moodle_exception If the item doesn't exist or is of wrong module name
    2205   */
    2206  function get_course_and_cm_from_instance($instanceorid, $modulename, $courseorid = 0, $userid = 0) {
    2207      global $DB;
    2208  
    2209      // Get data from parameter.
    2210      if (is_object($instanceorid)) {
    2211          $instanceid = $instanceorid->id;
    2212          if (isset($instanceorid->course)) {
    2213              $courseid = (int)$instanceorid->course;
    2214          } else {
    2215              $courseid = 0;
    2216          }
    2217      } else {
    2218          $instanceid = (int)$instanceorid;
    2219          $courseid = 0;
    2220      }
    2221  
    2222      // Get course from last parameter if supplied.
    2223      $course = null;
    2224      if (is_object($courseorid)) {
    2225          $course = $courseorid;
    2226      } else if ($courseorid) {
    2227          $courseid = (int)$courseorid;
    2228      }
    2229  
    2230      // Validate module name if supplied.
    2231      if (!core_component::is_valid_plugin_name('mod', $modulename)) {
    2232          throw new coding_exception('Invalid modulename parameter');
    2233      }
    2234  
    2235      if (!$course) {
    2236          if ($courseid) {
    2237              // If course ID is known, get it using normal function.
    2238              $course = get_course($courseid);
    2239          } else {
    2240              // Get course record in a single query based on instance id.
    2241              $pagetable = '{' . $modulename . '}';
    2242              $course = $DB->get_record_sql("
    2243                      SELECT c.*
    2244                        FROM $pagetable instance
    2245                        JOIN {course} c ON c.id = instance.course
    2246                       WHERE instance.id = ?", array($instanceid), MUST_EXIST);
    2247          }
    2248      }
    2249  
    2250      // Get cm from get_fast_modinfo.
    2251      $modinfo = get_fast_modinfo($course, $userid);
    2252      $instances = $modinfo->get_instances_of($modulename);
    2253      if (!array_key_exists($instanceid, $instances)) {
    2254          throw new moodle_exception('invalidmoduleid', 'error', $instanceid);
    2255      }
    2256      return array($course, $instances[$instanceid]);
    2257  }
    2258  
    2259  
    2260  /**
    2261   * Rebuilds or resets the cached list of course activities stored in MUC.
    2262   *
    2263   * rebuild_course_cache() must NEVER be called from lib/db/upgrade.php.
    2264   * At the same time course cache may ONLY be cleared using this function in
    2265   * upgrade scripts of plugins.
    2266   *
    2267   * During the bulk operations if it is necessary to reset cache of multiple
    2268   * courses it is enough to call {@link increment_revision_number()} for the
    2269   * table 'course' and field 'cacherev' specifying affected courses in select.
    2270   *
    2271   * Cached course information is stored in MUC core/coursemodinfo and is
    2272   * validated with the DB field {course}.cacherev
    2273   *
    2274   * @global moodle_database $DB
    2275   * @param int $courseid id of course to rebuild, empty means all
    2276   * @param boolean $clearonly only clear the cache, gets rebuild automatically on the fly.
    2277   *     Recommended to set to true to avoid unnecessary multiple rebuilding.
    2278   */
    2279  function rebuild_course_cache($courseid=0, $clearonly=false) {
    2280      global $COURSE, $SITE, $DB, $CFG;
    2281  
    2282      // Function rebuild_course_cache() can not be called during upgrade unless it's clear only.
    2283      if (!$clearonly && !upgrade_ensure_not_running(true)) {
    2284          $clearonly = true;
    2285      }
    2286  
    2287      // Destroy navigation caches
    2288      navigation_cache::destroy_volatile_caches();
    2289  
    2290      if (class_exists('format_base')) {
    2291          // if file containing class is not loaded, there is no cache there anyway
    2292          format_base::reset_course_cache($courseid);
    2293      }
    2294  
    2295      $cachecoursemodinfo = cache::make('core', 'coursemodinfo');
    2296      if (empty($courseid)) {
    2297          // Clearing caches for all courses.
    2298          increment_revision_number('course', 'cacherev', '');
    2299          $cachecoursemodinfo->purge();
    2300          course_modinfo::clear_instance_cache();
    2301          // Update global values too.
    2302          $sitecacherev = $DB->get_field('course', 'cacherev', array('id' => SITEID));
    2303          $SITE->cachrev = $sitecacherev;
    2304          if ($COURSE->id == SITEID) {
    2305              $COURSE->cacherev = $sitecacherev;
    2306          } else {
    2307              $COURSE->cacherev = $DB->get_field('course', 'cacherev', array('id' => $COURSE->id));
    2308          }
    2309      } else {
    2310          // Clearing cache for one course, make sure it is deleted from user request cache as well.
    2311          increment_revision_number('course', 'cacherev', 'id = :id', array('id' => $courseid));
    2312          $cachecoursemodinfo->delete($courseid);
    2313          course_modinfo::clear_instance_cache($courseid);
    2314          // Update global values too.
    2315          if ($courseid == $COURSE->id || $courseid == $SITE->id) {
    2316              $cacherev = $DB->get_field('course', 'cacherev', array('id' => $courseid));
    2317              if ($courseid == $COURSE->id) {
    2318                  $COURSE->cacherev = $cacherev;
    2319              }
    2320              if ($courseid == $SITE->id) {
    2321                  $SITE->cachrev = $cacherev;
    2322              }
    2323          }
    2324      }
    2325  
    2326      if ($clearonly) {
    2327          return;
    2328      }
    2329  
    2330      if ($courseid) {
    2331          $select = array('id'=>$courseid);
    2332      } else {
    2333          $select = array();
    2334          core_php_time_limit::raise();  // this could take a while!   MDL-10954
    2335      }
    2336  
    2337      $rs = $DB->get_recordset("course", $select,'','id,'.join(',', course_modinfo::$cachedfields));
    2338      // Rebuild cache for each course.
    2339      foreach ($rs as $course) {
    2340          course_modinfo::build_course_cache($course);
    2341      }
    2342      $rs->close();
    2343  }
    2344  
    2345  
    2346  /**
    2347   * Class that is the return value for the _get_coursemodule_info module API function.
    2348   *
    2349   * Note: For backward compatibility, you can also return a stdclass object from that function.
    2350   * The difference is that the stdclass object may contain an 'extra' field (deprecated,
    2351   * use extraclasses and onclick instead). The stdclass object may not contain
    2352   * the new fields defined here (content, extraclasses, customdata).
    2353   */
    2354  class cached_cm_info {
    2355      /**
    2356       * Name (text of link) for this activity; Leave unset to accept default name
    2357       * @var string
    2358       */
    2359      public $name;
    2360  
    2361      /**
    2362       * Name of icon for this activity. Normally, this should be used together with $iconcomponent
    2363       * to define the icon, as per pix_url function.
    2364       * For backward compatibility, if this value is of the form 'mod/forum/icon' then an icon
    2365       * within that module will be used.
    2366       * @see cm_info::get_icon_url()
    2367       * @see renderer_base::pix_url()
    2368       * @var string
    2369       */
    2370      public $icon;
    2371  
    2372      /**
    2373       * Component for icon for this activity, as per pix_url; leave blank to use default 'moodle'
    2374       * component
    2375       * @see renderer_base::pix_url()
    2376       * @var string
    2377       */
    2378      public $iconcomponent;
    2379  
    2380      /**
    2381       * HTML content to be displayed on the main page below the link (if any) for this course-module
    2382       * @var string
    2383       */
    2384      public $content;
    2385  
    2386      /**
    2387       * Custom data to be stored in modinfo for this activity; useful if there are cases when
    2388       * internal information for this activity type needs to be accessible from elsewhere on the
    2389       * course without making database queries. May be of any type but should be short.
    2390       * @var mixed
    2391       */
    2392      public $customdata;
    2393  
    2394      /**
    2395       * Extra CSS class or classes to be added when this activity is displayed on the main page;
    2396       * space-separated string
    2397       * @var string
    2398       */
    2399      public $extraclasses;
    2400  
    2401      /**
    2402       * External URL image to be used by activity as icon, useful for some external-tool modules
    2403       * like lti. If set, takes precedence over $icon and $iconcomponent
    2404       * @var $moodle_url
    2405       */
    2406      public $iconurl;
    2407  
    2408      /**
    2409       * Content of onclick JavaScript; escaped HTML to be inserted as attribute value
    2410       * @var string
    2411       */
    2412      public $onclick;
    2413  }
    2414  
    2415  
    2416  /**
    2417   * Data about a single section on a course. This contains the fields from the
    2418   * course_sections table, plus additional data when required.
    2419   *
    2420   * @property-read int $id Section ID - from course_sections table
    2421   * @property-read int $course Course ID - from course_sections table
    2422   * @property-read int $section Section number - from course_sections table
    2423   * @property-read string $name Section name if specified - from course_sections table
    2424   * @property-read int $visible Section visibility (1 = visible) - from course_sections table
    2425   * @property-read string $summary Section summary text if specified - from course_sections table
    2426   * @property-read int $summaryformat Section summary text format (FORMAT_xx constant) - from course_sections table
    2427   * @property-read string $availability Availability information as JSON string -
    2428   *    from course_sections table
    2429   * @property-read array $conditionscompletion Availability conditions for this section based on the completion of
    2430   *    course-modules (array from course-module id to required completion state
    2431   *    for that module) - from cached data in sectioncache field
    2432   * @property-read array $conditionsgrade Availability conditions for this section based on course grades (array from
    2433   *    grade item id to object with ->min, ->max fields) - from cached data in
    2434   *    sectioncache field
    2435   * @property-read array $conditionsfield Availability conditions for this section based on user fields
    2436   * @property-read bool $available True if this section is available to the given user i.e. if all availability conditions
    2437   *    are met - obtained dynamically
    2438   * @property-read string $availableinfo If section is not available to some users, this string gives information about
    2439   *    availability which can be displayed to students and/or staff (e.g. 'Available from 3 January 2010')
    2440   *    for display on main page - obtained dynamically
    2441   * @property-read bool $uservisible True if this section is available to the given user (for example, if current user
    2442   *    has viewhiddensections capability, they can access the section even if it is not
    2443   *    visible or not available, so this would be true in that case) - obtained dynamically
    2444   * @property-read string $sequence Comma-separated list of all modules in the section. Note, this field may not exactly
    2445   *    match course_sections.sequence if later has references to non-existing modules or not modules of not available module types.
    2446   * @property-read course_modinfo $modinfo
    2447   */
    2448  class section_info implements IteratorAggregate {
    2449      /**
    2450       * Section ID - from course_sections table
    2451       * @var int
    2452       */
    2453      private $_id;
    2454  
    2455      /**
    2456       * Section number - from course_sections table
    2457       * @var int
    2458       */
    2459      private $_section;
    2460  
    2461      /**
    2462       * Section name if specified - from course_sections table
    2463       * @var string
    2464       */
    2465      private $_name;
    2466  
    2467      /**
    2468       * Section visibility (1 = visible) - from course_sections table
    2469       * @var int
    2470       */
    2471      private $_visible;
    2472  
    2473      /**
    2474       * Section summary text if specified - from course_sections table
    2475       * @var string
    2476       */
    2477      private $_summary;
    2478  
    2479      /**
    2480       * Section summary text format (FORMAT_xx constant) - from course_sections table
    2481       * @var int
    2482       */
    2483      private $_summaryformat;
    2484  
    2485      /**
    2486       * Availability information as JSON string - from course_sections table
    2487       * @var string
    2488       */
    2489      private $_availability;
    2490  
    2491      /**
    2492       * Availability conditions for this section based on the completion of
    2493       * course-modules (array from course-module id to required completion state
    2494       * for that module) - from cached data in sectioncache field
    2495       * @var array
    2496       */
    2497      private $_conditionscompletion;
    2498  
    2499      /**
    2500       * Availability conditions for this section based on course grades (array from
    2501       * grade item id to object with ->min, ->max fields) - from cached data in
    2502       * sectioncache field
    2503       * @var array
    2504       */
    2505      private $_conditionsgrade;
    2506  
    2507      /**
    2508       * Availability conditions for this section based on user fields
    2509       * @var array
    2510       */
    2511      private $_conditionsfield;
    2512  
    2513      /**
    2514       * True if this section is available to students i.e. if all availability conditions
    2515       * are met - obtained dynamically on request, see function {@link section_info::get_available()}
    2516       * @var bool|null
    2517       */
    2518      private $_available;
    2519  
    2520      /**
    2521       * If section is not available to some users, this string gives information about
    2522       * availability which can be displayed to students and/or staff (e.g. 'Available from 3
    2523       * January 2010') for display on main page - obtained dynamically on request, see
    2524       * function {@link section_info::get_availableinfo()}
    2525       * @var string
    2526       */
    2527      private $_availableinfo;
    2528  
    2529      /**
    2530       * True if this section is available to the CURRENT user (for example, if current user
    2531       * has viewhiddensections capability, they can access the section even if it is not
    2532       * visible or not available, so this would be true in that case) - obtained dynamically
    2533       * on request, see function {@link section_info::get_uservisible()}
    2534       * @var bool|null
    2535       */
    2536      private $_uservisible;
    2537  
    2538      /**
    2539       * Default values for sectioncache fields; if a field has this value, it won't
    2540       * be stored in the sectioncache cache, to save space. Checks are done by ===
    2541       * which means values must all be strings.
    2542       * @var array
    2543       */
    2544      private static $sectioncachedefaults = array(
    2545          'name' => null,
    2546          'summary' => '',
    2547          'summaryformat' => '1', // FORMAT_HTML, but must be a string
    2548          'visible' => '1',
    2549          'availability' => null,
    2550      );
    2551  
    2552      /**
    2553       * Stores format options that have been cached when building 'coursecache'
    2554       * When the format option is requested we look first if it has been cached
    2555       * @var array
    2556       */
    2557      private $cachedformatoptions = array();
    2558  
    2559      /**
    2560       * Stores the list of all possible section options defined in each used course format.
    2561       * @var array
    2562       */
    2563      static private $sectionformatoptions = array();
    2564  
    2565      /**
    2566       * Stores the modinfo object passed in constructor, may be used when requesting
    2567       * dynamically obtained attributes such as available, availableinfo, uservisible.
    2568       * Also used to retrun information about current course or user.
    2569       * @var course_modinfo
    2570       */
    2571      private $modinfo;
    2572  
    2573      /**
    2574       * Constructs object from database information plus extra required data.
    2575       * @param object $data Array entry from cached sectioncache
    2576       * @param int $number Section number (array key)
    2577       * @param int $notused1 argument not used (informaion is available in $modinfo)
    2578       * @param int $notused2 argument not used (informaion is available in $modinfo)
    2579       * @param course_modinfo $modinfo Owner (needed for checking availability)
    2580       * @param int $notused3 argument not used (informaion is available in $modinfo)
    2581       */
    2582      public function __construct($data, $number, $notused1, $notused2, $modinfo, $notused3) {
    2583          global $CFG;
    2584          require_once($CFG->dirroot.'/course/lib.php');
    2585  
    2586          // Data that is always present
    2587          $this->_id = $data->id;
    2588  
    2589          $defaults = self::$sectioncachedefaults +
    2590                  array('conditionscompletion' => array(),
    2591                      'conditionsgrade' => array(),
    2592                      'conditionsfield' => array());
    2593  
    2594          // Data that may use default values to save cache size
    2595          foreach ($defaults as $field => $value) {
    2596              if (isset($data->{$field})) {
    2597                  $this->{'_'.$field} = $data->{$field};
    2598              } else {
    2599                  $this->{'_'.$field} = $value;
    2600              }
    2601          }
    2602  
    2603          // Other data from constructor arguments.
    2604          $this->_section = $number;
    2605          $this->modinfo = $modinfo;
    2606  
    2607          // Cached course format data.
    2608          $course = $modinfo->get_course();
    2609          if (!isset(self::$sectionformatoptions[$course->format])) {
    2610              // Store list of section format options defined in each used course format.
    2611              // They do not depend on particular course but only on its format.
    2612              self::$sectionformatoptions[$course->format] =
    2613                      course_get_format($course)->section_format_options();
    2614          }
    2615          foreach (self::$sectionformatoptions[$course->format] as $field => $option) {
    2616              if (!empty($option['cache'])) {
    2617                  if (isset($data->{$field})) {
    2618                      $this->cachedformatoptions[$field] = $data->{$field};
    2619                  } else if (array_key_exists('cachedefault', $option)) {
    2620                      $this->cachedformatoptions[$field] = $option['cachedefault'];
    2621                  }
    2622              }
    2623          }
    2624      }
    2625  
    2626      /**
    2627       * Magic method to check if the property is set
    2628       *
    2629       * @param string $name name of the property
    2630       * @return bool
    2631       */
    2632      public function __isset($name) {
    2633          if (method_exists($this, 'get_'.$name) ||
    2634                  property_exists($this, '_'.$name) ||
    2635                  array_key_exists($name, self::$sectionformatoptions[$this->modinfo->get_course()->format])) {
    2636              $value = $this->__get($name);
    2637              return isset($value);
    2638          }
    2639          return false;
    2640      }
    2641  
    2642      /**
    2643       * Magic method to check if the property is empty
    2644       *
    2645       * @param string $name name of the property
    2646       * @return bool
    2647       */
    2648      public function __empty($name) {
    2649          if (method_exists($this, 'get_'.$name) ||
    2650                  property_exists($this, '_'.$name) ||
    2651                  array_key_exists($name, self::$sectionformatoptions[$this->modinfo->get_course()->format])) {
    2652              $value = $this->__get($name);
    2653              return empty($value);
    2654          }
    2655          return true;
    2656      }
    2657  
    2658      /**
    2659       * Magic method to retrieve the property, this is either basic section property
    2660       * or availability information or additional properties added by course format
    2661       *
    2662       * @param string $name name of the property
    2663       * @return bool
    2664       */
    2665      public function __get($name) {
    2666          if (method_exists($this, 'get_'.$name)) {
    2667              return $this->{'get_'.$name}();
    2668          }
    2669          if (property_exists($this, '_'.$name)) {
    2670              return $this->{'_'.$name};
    2671          }
    2672          if (array_key_exists($name, $this->cachedformatoptions)) {
    2673              return $this->cachedformatoptions[$name];
    2674          }
    2675          // precheck if the option is defined in format to avoid unnecessary DB queries in get_format_options()
    2676          if (array_key_exists($name, self::$sectionformatoptions[$this->modinfo->get_course()->format])) {
    2677              $formatoptions = course_get_format($this->modinfo->get_course())->get_format_options($this);
    2678              return $formatoptions[$name];
    2679          }
    2680          debugging('Invalid section_info property accessed! '.$name);
    2681          return null;
    2682      }
    2683  
    2684      /**
    2685       * Finds whether this section is available at the moment for the current user.
    2686       *
    2687       * The value can be accessed publicly as $sectioninfo->available
    2688       *
    2689       * @return bool
    2690       */
    2691      private function get_available() {
    2692          global $CFG;
    2693          $userid = $this->modinfo->get_user_id();
    2694          if ($this->_available !== null || $userid == -1) {
    2695              // Has already been calculated or does not need calculation.
    2696              return $this->_available;
    2697          }
    2698          $this->_available = true;
    2699          $this->_availableinfo = '';
    2700          if (!empty($CFG->enableavailability)) {
    2701              require_once($CFG->libdir. '/conditionlib.php');
    2702              // Get availability information.
    2703              $ci = new \core_availability\info_section($this);
    2704              $this->_available = $ci->is_available($this->_availableinfo, true,
    2705                      $userid, $this->modinfo);
    2706          }
    2707          // Execute the hook from the course format that may override the available/availableinfo properties.
    2708          $currentavailable = $this->_available;
    2709          course_get_format($this->modinfo->get_course())->
    2710              section_get_available_hook($this, $this->_available, $this->_availableinfo);
    2711          if (!$currentavailable && $this->_available) {
    2712              debugging('section_get_available_hook() can not make unavailable section available', DEBUG_DEVELOPER);
    2713              $this->_available = $currentavailable;
    2714          }
    2715          return $this->_available;
    2716      }
    2717  
    2718      /**
    2719       * Returns the availability text shown next to the section on course page.
    2720       *
    2721       * @return string
    2722       */
    2723      private function get_availableinfo() {
    2724          // Calling get_available() will also fill the availableinfo property
    2725          // (or leave it null if there is no userid).
    2726          $this->get_available();
    2727          return $this->_availableinfo;
    2728      }
    2729  
    2730      /**
    2731       * Implementation of IteratorAggregate::getIterator(), allows to cycle through properties
    2732       * and use {@link convert_to_array()}
    2733       *
    2734       * @return ArrayIterator
    2735       */
    2736      public function getIterator() {
    2737          $ret = array();
    2738          foreach (get_object_vars($this) as $key => $value) {
    2739              if (substr($key, 0, 1) == '_') {
    2740                  if (method_exists($this, 'get'.$key)) {
    2741                      $ret[substr($key, 1)] = $this->{'get'.$key}();
    2742                  } else {
    2743                      $ret[substr($key, 1)] = $this->$key;
    2744                  }
    2745              }
    2746          }
    2747          $ret['sequence'] = $this->get_sequence();
    2748          $ret['course'] = $this->get_course();
    2749          $ret = array_merge($ret, course_get_format($this->modinfo->get_course())->get_format_options($this->_section));
    2750          return new ArrayIterator($ret);
    2751      }
    2752  
    2753      /**
    2754       * Works out whether activity is visible *for current user* - if this is false, they
    2755       * aren't allowed to access it.
    2756       *
    2757       * @return bool
    2758       */
    2759      private function get_uservisible() {
    2760          $userid = $this->modinfo->get_user_id();
    2761          if ($this->_uservisible !== null || $userid == -1) {
    2762              // Has already been calculated or does not need calculation.
    2763              return $this->_uservisible;
    2764          }
    2765          $this->_uservisible = true;
    2766          if (!$this->_visible || !$this->get_available()) {
    2767              $coursecontext = context_course::instance($this->get_course());
    2768              if (!has_capability('moodle/course:viewhiddensections', $coursecontext, $userid)) {
    2769                  $this->_uservisible = false;
    2770              }
    2771          }
    2772          return $this->_uservisible;
    2773      }
    2774  
    2775      /**
    2776       * Getter method for property $showavailability. Works by checking the
    2777       * availableinfo property to see if it's empty or not.
    2778       *
    2779       * @return int
    2780       * @deprecated Since Moodle 2.7
    2781       */
    2782      private function get_showavailability() {
    2783          debugging('$section->showavailability property has been deprecated. You ' .
    2784                  'can replace it by checking if $section->availableinfo has content.',
    2785                  DEBUG_DEVELOPER);
    2786          return ($this->get_availableinfo() !== '') ? 1 : 0;
    2787      }
    2788  
    2789      /**
    2790       * Getter method for $availablefrom. Just returns zero as no longer supported.
    2791       *
    2792       * @return int Zero
    2793       * @deprecated Since Moodle 2.7
    2794       */
    2795      private function get_availablefrom() {
    2796          debugging('$section->availablefrom has been deprecated. This ' .
    2797                  'information is no longer available as the system provides more complex ' .
    2798                  'options (for example, there might be different dates for different users).',
    2799                  DEBUG_DEVELOPER);
    2800          return 0;
    2801      }
    2802  
    2803      /**
    2804       * Getter method for $availablefrom. Just returns zero as no longer supported.
    2805       *
    2806       * @return int Zero
    2807       * @deprecated Since Moodle 2.7
    2808       */
    2809      private function get_availableuntil() {
    2810          debugging('$section->availableuntil has been deprecated. This ' .
    2811                  'information is no longer available as the system provides more complex ' .
    2812                  'options (for example, there might be different dates for different users).',
    2813                  DEBUG_DEVELOPER);
    2814          return 0;
    2815      }
    2816  
    2817      /**
    2818       * Getter method for $groupingid. Just returns zero as no longer supported.
    2819       *
    2820       * @return int Zero
    2821       * @deprecated Since Moodle 2.7
    2822       */
    2823      private function get_groupingid() {
    2824          debugging('$section->groupingid has been deprecated. This ' .
    2825                  'information is no longer available as the system provides more complex ' .
    2826                  'options (for example, combining multiple groupings).',
    2827                  DEBUG_DEVELOPER);
    2828          return 0;
    2829      }
    2830  
    2831      /**
    2832       * Restores the course_sections.sequence value
    2833       *
    2834       * @return string
    2835       */
    2836      private function get_sequence() {
    2837          if (!empty($this->modinfo->sections[$this->_section])) {
    2838              return implode(',', $this->modinfo->sections[$this->_section]);
    2839          } else {
    2840              return '';
    2841          }
    2842      }
    2843  
    2844      /**
    2845       * Returns course ID - from course_sections table
    2846       *
    2847       * @return int
    2848       */
    2849      private function get_course() {
    2850          return $this->modinfo->get_course_id();
    2851      }
    2852  
    2853      /**
    2854       * Modinfo object
    2855       *
    2856       * @return course_modinfo
    2857       */
    2858      private function get_modinfo() {
    2859          return $this->modinfo;
    2860      }
    2861  
    2862      /**
    2863       * Prepares section data for inclusion in sectioncache cache, removing items
    2864       * that are set to defaults, and adding availability data if required.
    2865       *
    2866       * Called by build_section_cache in course_modinfo only; do not use otherwise.
    2867       * @param object $section Raw section data object
    2868       */
    2869      public static function convert_for_section_cache($section) {
    2870          global $CFG;
    2871  
    2872          // Course id stored in course table
    2873          unset($section->course);
    2874          // Section number stored in array key
    2875          unset($section->section);
    2876          // Sequence stored implicity in modinfo $sections array
    2877          unset($section->sequence);
    2878  
    2879          // Remove default data
    2880          foreach (self::$sectioncachedefaults as $field => $value) {
    2881              // Exact compare as strings to avoid problems if some strings are set
    2882              // to "0" etc.
    2883              if (isset($section->{$field}) && $section->{$field} === $value) {
    2884                  unset($section->{$field});
    2885              }
    2886          }
    2887      }
    2888  }
    

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