lib/grouplib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  20  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  21  * @package    core
  22  * @subpackage group
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die();
  26
  27 /**
  28  * Groups not used in course or activity
  29  */
  30 define('NOGROUPS', 0);
  31
  32 /**
  33  * Groups used, users do not see other groups
  34  */
  35 define('SEPARATEGROUPS', 1);
  36
  37 /**
  38  * Groups used, students see other groups
  39  */
  40 define('VISIBLEGROUPS', 2);
  41
  42
  43 /**
  44  * Determines if a group with a given groupid exists.
  45  *
  46  * @global object
  47  * @param int $groupid The groupid to check for
  48  * @return boolean True if the group exists, false otherwise or if an error
  49  * occurred.
  50  */
  51 function groups_group_exists($groupid) {
  52     global $DB;
  53     return $DB->record_exists('groups', array('id'=>$groupid));
  54 }
  55
  56 /**
  57  * Gets the name of a group with a specified id
  58  *
  59  * @global object
  60  * @param int $groupid The id of the group
  61  * @return string The name of the group
  62  */
  63 function groups_get_group_name($groupid) {
  64     global $DB;
  65     return $DB->get_field('groups', 'name', array('id'=>$groupid));
  66 }
  67
  68 /**
  69  * Gets the name of a grouping with a specified id
  70  *
  71  * @global object
  72  * @param int $groupingid The id of the grouping
  73  * @return string The name of the grouping
  74  */
  75 function groups_get_grouping_name($groupingid) {
  76     global $DB;
  77     return $DB->get_field('groupings', 'name', array('id'=>$groupingid));
  78 }
  79
  80 /**
  81  * Returns the groupid of a group with the name specified for the course.
  82  * Group names should be unique in course
  83  *
  84  * @global object
  85  * @param int $courseid The id of the course
  86  * @param string $name name of group (without magic quotes)
  87  * @return int $groupid
  88  */
  89 function groups_get_group_by_name($courseid, $name) {
  90     global $DB;
  91     if ($groups = $DB->get_records('groups', array('courseid'=>$courseid, 'name'=>$name))) {
  92         return key($groups);
  93     }
  94     return false;
  95 }
  96
  97 /**
  98  * Returns the groupingid of a grouping with the name specified for the course.
  99  * Grouping names should be unique in course
 100  *
 101  * @global object
 102  * @param int $courseid The id of the course
 103  * @param string $name name of group (without magic quotes)
 104  * @return int $groupid
 105  */
 106 function groups_get_grouping_by_name($courseid, $name) {
 107     global $DB;
 108     if ($groupings = $DB->get_records('groupings', array('courseid'=>$courseid, 'name'=>$name))) {
 109         return key($groupings);
 110     }
 111     return false;
 112 }
 113
 114 /**
 115  * Get the group object
 116  *
 117  * @param int $groupid ID of the group.
 118  * @return object group object
 119  */
 120 function groups_get_group($groupid, $fields='*', $strictness=IGNORE_MISSING) {
 121     global $DB;
 122     return $DB->get_record('groups', array('id'=>$groupid), $fields, $strictness);
 123 }
 124
 125 /**
 126  * Get the grouping object
 127  *
 128  * @param int $groupingid ID of the group.
 129  * @param string $fields
 130  * @return object group object
 131  */
 132 function groups_get_grouping($groupingid, $fields='*', $strictness=IGNORE_MISSING) {
 133     global $DB;
 134     return $DB->get_record('groupings', array('id'=>$groupingid), $fields, $strictness);
 135 }
 136
 137 /**
 138  * Gets array of all groups in a specified course.
 139  *
 140  * @param int $courseid The id of the course.
 141  * @param mixed $userid optional user id or array of ids, returns only groups of the user.
 142  * @param int $groupingid optional returns only groups in the specified grouping.
 143  * @param string $fields
 144  * @return array Returns an array of the group objects (userid field returned if array in $userid)
 145  */
 146 function groups_get_all_groups($courseid, $userid=0, $groupingid=0, $fields='g.*') {
 147     global $DB;
 148
 149     if (empty($userid)) {
 150         $userfrom  = "";
 151         $userwhere = "";
 152         $params = array();
 153
 154     } else {
 155         list($usql, $params) = $DB->get_in_or_equal($userid);
 156         $userfrom  = ", {groups_members} gm";
 157         $userwhere = "AND g.id = gm.groupid AND gm.userid $usql";
 158     }
 159
 160     if (!empty($groupingid)) {
 161         $groupingfrom  = ", {groupings_groups} gg";
 162         $groupingwhere = "AND g.id = gg.groupid AND gg.groupingid = ?";
 163         $params[] = $groupingid;
 164     } else {
 165         $groupingfrom  = "";
 166         $groupingwhere = "";
 167     }
 168
 169     array_unshift($params, $courseid);
 170
 171     return $DB->get_records_sql("SELECT $fields
 172                                    FROM {groups} g $userfrom $groupingfrom
 173                                   WHERE g.courseid = ? $userwhere $groupingwhere
 174                                ORDER BY name ASC", $params);
 175 }
 176
 177 /**
 178  * Returns info about user's groups in course.
 179  *
 180  * @param int $courseid
 181  * @param int $userid $USER if not specified
 182  * @return array Array[groupingid][groupid] including grouping id 0 which means all groups
 183  */
 184 function groups_get_user_groups($courseid, $userid=0) {
 185     global $USER, $DB;
 186
 187     if (empty($userid)) {
 188         $userid = $USER->id;
 189     }
 190
 191     $sql = "SELECT g.id, gg.groupingid
 192               FROM {groups} g
 193                    JOIN {groups_members} gm   ON gm.groupid = g.id
 194               LEFT JOIN {groupings_groups} gg ON gg.groupid = g.id
 195              WHERE gm.userid = ? AND g.courseid = ?";
 196     $params = array($userid, $courseid);
 197
 198     $rs = $DB->get_recordset_sql($sql, $params);
 199
 200     if (!$rs->valid()) {
 201         $rs->close(); // Not going to iterate (but exit), close rs
 202         return array('0' => array());
 203     }
 204
 205     $result    = array();
 206     $allgroups = array();
 207
 208     foreach ($rs as $group) {
 209         $allgroups[$group->id] = $group->id;
 210         if (is_null($group->groupingid)) {
 211             continue;
 212         }
 213         if (!array_key_exists($group->groupingid, $result)) {
 214             $result[$group->groupingid] = array();
 215         }
 216         $result[$group->groupingid][$group->id] = $group->id;
 217     }
 218     $rs->close();
 219
 220     $result['0'] = array_keys($allgroups); // all groups
 221
 222     return $result;
 223 }
 224
 225 /**
 226  * Gets array of all groupings in a specified course.
 227  *
 228  * @global object
 229  * @global object
 230  * @param int $courseid return only groupings in this with this courseid
 231  * @return array|bool Returns an array of the grouping objects or false if no records
 232  * or an error occurred.
 233  */
 234 function groups_get_all_groupings($courseid) {
 235     global $CFG, $DB;
 236
 237     return $DB->get_records_sql("SELECT *
 238                                    FROM {groupings}
 239                                   WHERE courseid = ?
 240                                ORDER BY name ASC", array($courseid));
 241 }
 242
 243
 244
 245 /**
 246  * Determines if the user is a member of the given group.
 247  *
 248  * If $userid is null, use the global object.
 249  *
 250  * @global object
 251  * @global object
 252  * @param int $groupid The group to check for membership.
 253  * @param int $userid The user to check against the group.
 254  * @return boolean True if the user is a member, false otherwise.
 255  */
 256 function groups_is_member($groupid, $userid=null) {
 257     global $USER, $DB;
 258
 259     if (!$userid) {
 260         $userid = $USER->id;
 261     }
 262
 263     return $DB->record_exists('groups_members', array('groupid'=>$groupid, 'userid'=>$userid));
 264 }
 265
 266 /**
 267  * Determines if current or specified is member of any active group in activity
 268  *
 269  * @global object
 270  * @global object
 271  * @global object
 272  * @staticvar array $cache
 273  * @param object $cm coruse module object
 274  * @param int $userid id of user, null menas $USER->id
 275  * @return booelan true if user member of at least one group used in activity
 276  */
 277 function groups_has_membership($cm, $userid=null) {
 278     global $CFG, $USER, $DB;
 279
 280     static $cache = array();
 281
 282     if (empty($userid)) {
 283         $userid = $USER->id;
 284     }
 285
 286     $cachekey = $userid.'|'.$cm->course.'|'.$cm->groupingid;
 287     if (isset($cache[$cachekey])) {
 288         return($cache[$cachekey]);
 289     }
 290
 291     if ($cm->groupingid) {
 292         // find out if member of any group in selected activity grouping
 293         $sql = "SELECT 'x'
 294                   FROM {groups_members} gm, {groupings_groups} gg
 295                  WHERE gm.userid = ? AND gm.groupid = gg.groupid AND gg.groupingid = ?";
 296         $params = array($userid, $cm->groupingid);
 297
 298     } else {
 299         // no grouping used - check all groups in course
 300         $sql = "SELECT 'x'
 301                   FROM {groups_members} gm, {groups} g
 302                  WHERE gm.userid = ? AND gm.groupid = g.id AND g.courseid = ?";
 303         $params = array($userid, $cm->course);
 304     }
 305
 306     $cache[$cachekey] = $DB->record_exists_sql($sql, $params);
 307
 308     return $cache[$cachekey];
 309 }
 310
 311 /**
 312  * Returns the users in the specified group.
 313  *
 314  * @global object
 315  * @param int $groupid The groupid to get the users for
 316  * @param int $fields The fields to return
 317  * @param int $sort optional sorting of returned users
 318  * @return array|bool Returns an array of the users for the specified
 319  * group or false if no users or an error returned.
 320  */
 321 function groups_get_members($groupid, $fields='u.*', $sort='lastname ASC') {
 322     global $DB;
 323
 324     return $DB->get_records_sql("SELECT $fields
 325                                    FROM {user} u, {groups_members} gm
 326                                   WHERE u.id = gm.userid AND gm.groupid = ?
 327                                ORDER BY $sort", array($groupid));
 328 }
 329
 330
 331 /**
 332  * Returns the users in the specified grouping.
 333  *
 334  * @global object
 335  * @param int $groupingid The groupingid to get the users for
 336  * @param int $fields The fields to return
 337  * @param int $sort optional sorting of returned users
 338  * @return array|bool Returns an array of the users for the specified
 339  * group or false if no users or an error returned.
 340  */
 341 function groups_get_grouping_members($groupingid, $fields='u.*', $sort='lastname ASC') {
 342     global $DB;
 343
 344     return $DB->get_records_sql("SELECT $fields
 345                                    FROM {user} u
 346                                      INNER JOIN {groups_members} gm ON u.id = gm.userid
 347                                      INNER JOIN {groupings_groups} gg ON gm.groupid = gg.groupid
 348                                   WHERE  gg.groupingid = ?
 349                                ORDER BY $sort", array($groupingid));
 350 }
 351
 352 /**
 353  * Returns effective groupmode used in course
 354  *
 355  * @return integer group mode
 356  */
 357 function groups_get_course_groupmode($course) {
 358     return $course->groupmode;
 359 }
 360
 361 /**
 362  * Returns effective groupmode used in activity, course setting
 363  * overrides activity setting if groupmodeforce enabled.
 364  *
 365  * @global object
 366  * @global object
 367  * @param object $cm the course module object. Only the ->course and ->groupmode need to be set.
 368  * @param object $course object optional course object to improve perf
 369  * @return integer group mode
 370  */
 371 function groups_get_activity_groupmode($cm, $course=null) {
 372     global $COURSE, $DB;
 373
 374     // get course object (reuse COURSE if possible)
 375     if (isset($course->id) and $course->id == $cm->course) {
 376         //ok
 377     } else if ($cm->course == $COURSE->id) {
 378         $course = $COURSE;
 379     } else {
 380         if (!$course = $DB->get_record('course', array('id'=>$cm->course))) {
 381             print_error('invalidcourseid');
 382         }
 383     }
 384
 385     return empty($course->groupmodeforce) ? $cm->groupmode : $course->groupmode;
 386 }
 387
 388 /**
 389  * Print group menu selector for course level.
 390  *
 391  * @param stdClass $course course object
 392  * @param string|moodle_url $urlroot return address
 393  * @param boolean $return return as string instead of printing
 394  * @return mixed void or string depending on $return param
 395  */
 396 function groups_print_course_menu($course, $urlroot, $return=false) {
 397     global $USER, $OUTPUT;
 398
 399     if (!$groupmode = $course->groupmode) {
 400         if ($return) {
 401             return '';
 402         } else {
 403             return;
 404         }
 405     }
 406
 407     $context = get_context_instance(CONTEXT_COURSE, $course->id);
 408     $aag = has_capability('moodle/site:accessallgroups', $context);
 409
 410     if ($groupmode == VISIBLEGROUPS or $aag) {
 411         $allowedgroups = groups_get_all_groups($course->id, 0, $course->defaultgroupingid);
 412     } else {
 413         $allowedgroups = groups_get_all_groups($course->id, $USER->id, $course->defaultgroupingid);
 414     }
 415
 416     $activegroup = groups_get_course_group($course, true, $allowedgroups);
 417
 418     $groupsmenu = array();
 419     if (!$allowedgroups or $groupmode == VISIBLEGROUPS or $aag) {
 420         $groupsmenu[0] = get_string('allparticipants');
 421     }
 422
 423     if ($allowedgroups) {
 424         foreach ($allowedgroups as $group) {
 425             $groupsmenu[$group->id] = format_string($group->name);
 426         }
 427     }
 428
 429     if ($groupmode == VISIBLEGROUPS) {
 430         $grouplabel = get_string('groupsvisible');
 431     } else {
 432         $grouplabel = get_string('groupsseparate');
 433     }
 434
 435     if ($aag and $course->defaultgroupingid) {
 436         if ($grouping = groups_get_grouping($course->defaultgroupingid)) {
 437             $grouplabel = $grouplabel . ' (' . format_string($grouping->name) . ')';
 438         }
 439     }
 440
 441     if (count($groupsmenu) == 1) {
 442         $groupname = reset($groupsmenu);
 443         $output = $grouplabel.': '.$groupname;
 444     } else {
 445         $select = new single_select(new moodle_url($urlroot), 'group', $groupsmenu, $activegroup, null, 'selectgroup');
 446         $select->label = $grouplabel;
 447         $output = $OUTPUT->render($select);
 448     }
 449
 450     $output = '<div class="groupselector">'.$output.'</div>';
 451
 452     if ($return) {
 453         return $output;
 454     } else {
 455         echo $output;
 456     }
 457 }
 458
 459 /**
 460  * Print group menu selector for activity.
 461  *
 462  * @param stdClass $cm course module object
 463  * @param string|moodle_url $urlroot return address that users get to if they choose an option;
 464  *   should include any parameters needed, e.g. "$CFG->wwwroot/mod/forum/view.php?id=34"
 465  * @param boolean $return return as string instead of printing
 466  * @param boolean $hideallparticipants If true, this prevents the 'All participants'
 467  *   option from appearing in cases where it normally would. This is intended for
 468  *   use only by activities that cannot display all groups together. (Note that
 469  *   selecting this option does not prevent groups_get_activity_group from
 470  *   returning 0; it will still do that if the user has chosen 'all participants'
 471  *   in another activity, or not chosen anything.)
 472  * @return mixed void or string depending on $return param
 473  */
 474 function groups_print_activity_menu($cm, $urlroot, $return=false, $hideallparticipants=false) {
 475     global $USER, $OUTPUT;
 476
 477     if ($urlroot instanceof moodle_url) {
 478         // no changes necessary
 479
 480     } else {
 481         if (strpos($urlroot, 'http') !== 0) { // Will also work for https
 482             // Display error if urlroot is not absolute (this causes the non-JS version to break)
 483             debugging('groups_print_activity_menu requires absolute URL for ' .
 484                       '$urlroot, not <tt>' . s($urlroot) . '</tt>. Example: ' .
 485                       'groups_print_activity_menu($cm, $CFG->wwwroot . \'/mod/mymodule/view.php?id=13\');',
 486                       DEBUG_DEVELOPER);
 487         }
 488         $urlroot = new moodle_url($urlroot);
 489     }
 490
 491     if (!$groupmode = groups_get_activity_groupmode($cm)) {
 492         if ($return) {
 493             return '';
 494         } else {
 495             return;
 496         }
 497     }
 498
 499     $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 500     $aag = has_capability('moodle/site:accessallgroups', $context);
 501
 502     if ($groupmode == VISIBLEGROUPS or $aag) {
 503         $allowedgroups = groups_get_all_groups($cm->course, 0, $cm->groupingid); // any group in grouping
 504     } else {
 505         $allowedgroups = groups_get_all_groups($cm->course, $USER->id, $cm->groupingid); // only assigned groups
 506     }
 507
 508     $activegroup = groups_get_activity_group($cm, true, $allowedgroups);
 509
 510     $groupsmenu = array();
 511     if ((!$allowedgroups or $groupmode == VISIBLEGROUPS or $aag) and !$hideallparticipants) {
 512         $groupsmenu[0] = get_string('allparticipants');
 513     }
 514
 515     if ($allowedgroups) {
 516         foreach ($allowedgroups as $group) {
 517             $groupsmenu[$group->id] = format_string($group->name);
 518         }
 519     }
 520
 521     if ($groupmode == VISIBLEGROUPS) {
 522         $grouplabel = get_string('groupsvisible');
 523     } else {
 524         $grouplabel = get_string('groupsseparate');
 525     }
 526
 527     if ($aag and $cm->groupingid) {
 528         if ($grouping = groups_get_grouping($cm->groupingid)) {
 529             $grouplabel = $grouplabel . ' (' . format_string($grouping->name) . ')';
 530         }
 531     }
 532
 533     if (count($groupsmenu) == 1) {
 534         $groupname = reset($groupsmenu);
 535         $output = $grouplabel.': '.$groupname;
 536     } else {
 537         $select = new single_select($urlroot, 'group', $groupsmenu, $activegroup, null, 'selectgroup');
 538         $select->label = $grouplabel;
 539         $output = $OUTPUT->render($select);
 540     }
 541
 542     $output = '<div class="groupselector">'.$output.'</div>';
 543
 544     if ($return) {
 545         return $output;
 546     } else {
 547         echo $output;
 548     }
 549 }
 550
 551 /**
 552  * Returns group active in course, changes the group by default if 'group' page param present
 553  *
 554  * @param stdClass $course course bject
 555  * @param boolean $update change active group if group param submitted
 556  * @param array $allowedgroups list of groups user may access (INTERNAL, to be used only from groups_print_course_menu())
 557  * @return mixed false if groups not used, int if groups used, 0 means all groups (access must be verified in SEPARATE mode)
 558  */
 559 function groups_get_course_group($course, $update=false, $allowedgroups=null) {
 560     global $USER, $SESSION;
 561
 562     if (!$groupmode = $course->groupmode) {
 563         // NOGROUPS used
 564         return false;
 565     }
 566
 567     $context = get_context_instance(CONTEXT_COURSE, $course->id);
 568     if (has_capability('moodle/site:accessallgroups', $context)) {
 569         $groupmode = 'aag';
 570     }
 571
 572     if (!is_array($allowedgroups)) {
 573         if ($groupmode == VISIBLEGROUPS or $groupmode === 'aag') {
 574             $allowedgroups = groups_get_all_groups($course->id, 0, $course->defaultgroupingid);
 575         } else {
 576             $allowedgroups = groups_get_all_groups($course->id, $USER->id, $course->defaultgroupingid);
 577         }
 578     }
 579
 580     _group_verify_activegroup($course->id, $groupmode, $course->defaultgroupingid, $allowedgroups);
 581
 582     // set new active group if requested
 583     $changegroup = optional_param('group', -1, PARAM_INT);
 584     if ($update and $changegroup != -1) {
 585
 586         if ($changegroup == 0) {
 587             // do not allow changing to all groups without accessallgroups capability
 588             if ($groupmode == VISIBLEGROUPS or $groupmode === 'aag') {
 589                 $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid] = 0;
 590             }
 591
 592         } else {
 593             if ($allowedgroups and array_key_exists($changegroup, $allowedgroups)) {
 594                 $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid] = $changegroup;
 595             }
 596         }
 597     }
 598
 599     return $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid];
 600 }
 601
 602 /**
 603  * Returns group active in activity, changes the group by default if 'group' page param present
 604  *
 605  * @param stdClass $cm course module object
 606  * @param boolean $update change active group if group param submitted
 607  * @param array $allowedgroups list of groups user may access (INTERNAL, to be used only from groups_print_activity_menu())
 608  * @return mixed false if groups not used, int if groups used, 0 means all groups (access must be verified in SEPARATE mode)
 609  */
 610 function groups_get_activity_group($cm, $update=false, $allowedgroups=null) {
 611     global $USER, $SESSION;
 612
 613     if (!$groupmode = groups_get_activity_groupmode($cm)) {
 614         // NOGROUPS used
 615         return false;
 616     }
 617
 618     $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 619     if (has_capability('moodle/site:accessallgroups', $context)) {
 620         $groupmode = 'aag';
 621     }
 622
 623     if (!is_array($allowedgroups)) {
 624         if ($groupmode == VISIBLEGROUPS or $groupmode === 'aag') {
 625             $allowedgroups = groups_get_all_groups($cm->course, 0, $cm->groupingid);
 626         } else {
 627             $allowedgroups = groups_get_all_groups($cm->course, $USER->id, $cm->groupingid);
 628         }
 629     }
 630
 631     _group_verify_activegroup($cm->course, $groupmode, $cm->groupingid, $allowedgroups);
 632
 633     // set new active group if requested
 634     $changegroup = optional_param('group', -1, PARAM_INT);
 635     if ($update and $changegroup != -1) {
 636
 637         if ($changegroup == 0) {
 638             // allgroups visible only in VISIBLEGROUPS or when accessallgroups
 639             if ($groupmode == VISIBLEGROUPS or $groupmode === 'aag') {
 640                 $SESSION->activegroup[$cm->course][$groupmode][$cm->groupingid] = 0;
 641             }
 642
 643         } else {
 644             if ($allowedgroups and array_key_exists($changegroup, $allowedgroups)) {
 645                 $SESSION->activegroup[$cm->course][$groupmode][$cm->groupingid] = $changegroup;
 646             }
 647         }
 648     }
 649
 650     return $SESSION->activegroup[$cm->course][$groupmode][$cm->groupingid];
 651 }
 652
 653 /**
 654  * Gets a list of groups that the user is allowed to access within the
 655  * specified activity.
 656  *
 657  * @param object $cm Course-module
 658  * @param int $userid User ID (defaults to current user)
 659  * @return array An array of group objects, or false if none
 660  */
 661 function groups_get_activity_allowed_groups($cm,$userid=0) {
 662     // Use current user by default
 663     global $USER;
 664     if(!$userid) {
 665         $userid=$USER->id;
 666     }
 667
 668     // Get groupmode for activity, taking into account course settings
 669     $groupmode=groups_get_activity_groupmode($cm);
 670
 671     // If visible groups mode, or user has the accessallgroups capability,
 672     // then they can access all groups for the activity...
 673     $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 674     if ($groupmode == VISIBLEGROUPS or has_capability('moodle/site:accessallgroups', $context)) {
 675         return groups_get_all_groups($cm->course, 0, $cm->groupingid);
 676     } else {
 677         // ...otherwise they can only access groups they belong to
 678         return groups_get_all_groups($cm->course, $userid, $cm->groupingid);
 679     }
 680 }
 681
 682 /**
 683  * Determine if a course module is currently visible to a user
 684  *
 685  * $USER If $userid is null, use the global object.
 686  *
 687  * @param int $cm The course module
 688  * @param int $userid The user to check against the group.
 689  * @return boolean True if the user can view the course module, false otherwise.
 690  */
 691 function groups_course_module_visible($cm, $userid=null) {
 692     global $CFG, $USER;
 693
 694     if (empty($userid)) {
 695         $userid = $USER->id;
 696     }
 697     if (empty($CFG->enablegroupmembersonly)) {
 698         return true;
 699     }
 700     if (empty($cm->groupmembersonly)) {
 701         return true;
 702     }
 703     if (has_capability('moodle/site:accessallgroups', get_context_instance(CONTEXT_MODULE, $cm->id), $userid) or groups_has_membership($cm, $userid)) {
 704         return true;
 705     }
 706     return false;
 707 }
 708
 709 /**
 710  * Internal method, sets up $SESSION->activegroup and verifies previous value
 711  *
 712  * @private
 713  * @param int $courseid
 714  * @param int|string $groupmode SEPARATEGROUPS, VISIBLEGROUPS or 'aag' (access all groups)
 715  * @param int $groupingid 0 means all groups
 716  * @param all $allowedgroups list of groups user can see
 717  * @return void
 718  */
 719 function _group_verify_activegroup($courseid, $groupmode, $groupingid, array $allowedgroups) {
 720     global $SESSION;
 721
 722     // init activegroup array if necessary
 723     if (!isset($SESSION->activegroup)) {
 724         $SESSION->activegroup = array();
 725     }
 726     if (!array_key_exists($courseid, $SESSION->activegroup)) {
 727         $SESSION->activegroup[$courseid] = array(SEPARATEGROUPS=>array(), VISIBLEGROUPS=>array(), 'aag'=>array());
 728     }
 729
 730     // make sure that the current group info is ok
 731     if (array_key_exists($groupingid, $SESSION->activegroup[$courseid][$groupmode]) and !array_key_exists($SESSION->activegroup[$courseid][$groupmode][$groupingid], $allowedgroups)) {
 732         // active group does not exist anymore or is 0
 733         if ($SESSION->activegroup[$courseid][$groupmode][$groupingid] > 0 or $groupmode == SEPARATEGROUPS) {
 734             // do not do this if all groups selected and groupmode is not separate
 735             unset($SESSION->activegroup[$courseid][$groupmode][$groupingid]);
 736         }
 737     }
 738
 739     // set up defaults if necessary
 740     if (!array_key_exists($groupingid, $SESSION->activegroup[$courseid][$groupmode])) {
 741         if ($groupmode == 'aag') {
 742             $SESSION->activegroup[$courseid][$groupmode][$groupingid] = 0; // all groups by default if user has accessallgroups
 743
 744         } else if ($allowedgroups) {
 745             $firstgroup = reset($allowedgroups);
 746             $SESSION->activegroup[$courseid][$groupmode][$groupingid] = $firstgroup->id;
 747
 748         } else {
 749             // this happen when user not assigned into group in SEPARATEGROUPS mode or groups do not exist yet
 750             // mod authors must add extra checks for this when SEPARATEGROUPS mode used (such as when posting to forum)
 751             $SESSION->activegroup[$courseid][$groupmode][$groupingid] = 0;
 752         }
 753     }
 754 }