lib/datalib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Library of functions for database manipulation.
  19  *
  20  * Other main libraries:
  21  * - weblib.php - functions that produce web output
  22  * - moodlelib.php - general-purpose Moodle functions
  23  *
  24  * @package    core
  25  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  26  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 defined('MOODLE_INTERNAL') || die();
  30
  31 /**
  32  * The maximum courses in a category
  33  * MAX_COURSES_IN_CATEGORY * MAX_COURSE_CATEGORIES must not be more than max integer!
  34  */
  35 define('MAX_COURSES_IN_CATEGORY', 10000);
  36
  37 /**
  38   * The maximum number of course categories
  39   * MAX_COURSES_IN_CATEGORY * MAX_COURSE_CATEGORIES must not be more than max integer!
  40   */
  41 define('MAX_COURSE_CATEGORIES', 10000);
  42
  43 /**
  44  * Number of seconds to wait before updating lastaccess information in DB.
  45  *
  46  * We allow overwrites from config.php, useful to ensure coherence in performance
  47  * tests results.
  48  *
  49  * Note: For web service requests in the external_tokens field, we use a different constant
  50  * webservice::TOKEN_LASTACCESS_UPDATE_SECS.
  51  */
  52 if (!defined('LASTACCESS_UPDATE_SECS')) {
  53     define('LASTACCESS_UPDATE_SECS', 60);
  54 }
  55
  56 /**
  57  * Returns $user object of the main admin user
  58  *
  59  * @static stdClass $mainadmin
  60  * @return stdClass {@link $USER} record from DB, false if not found
  61  */
  62 function get_admin() {
  63     global $CFG, $DB;
  64
  65     static $mainadmin = null;
  66     static $prevadmins = null;
  67
  68     if (empty($CFG->siteadmins)) {
  69         // Should not happen on an ordinary site.
  70         // It does however happen during unit tests.
  71         return false;
  72     }
  73
  74     if (isset($mainadmin) and $prevadmins === $CFG->siteadmins) {
  75         return clone($mainadmin);
  76     }
  77
  78     $mainadmin = null;
  79
  80     foreach (explode(',', $CFG->siteadmins) as $id) {
  81         if ($user = $DB->get_record('user', array('id'=>$id, 'deleted'=>0))) {
  82             $mainadmin = $user;
  83             break;
  84         }
  85     }
  86
  87     if ($mainadmin) {
  88         $prevadmins = $CFG->siteadmins;
  89         return clone($mainadmin);
  90     } else {
  91         // this should not happen
  92         return false;
  93     }
  94 }
  95
  96 /**
  97  * Returns list of all admins, using 1 DB query
  98  *
  99  * @return array
 100  */
 101 function get_admins() {
 102     global $DB, $CFG;
 103
 104     if (empty($CFG->siteadmins)) {  // Should not happen on an ordinary site
 105         return array();
 106     }
 107
 108     $sql = "SELECT u.*
 109               FROM {user} u
 110              WHERE u.deleted = 0 AND u.id IN ($CFG->siteadmins)";
 111
 112     // We want the same order as in $CFG->siteadmins.
 113     $records = $DB->get_records_sql($sql);
 114     $admins = array();
 115     foreach (explode(',', $CFG->siteadmins) as $id) {
 116         $id = (int)$id;
 117         if (!isset($records[$id])) {
 118             // User does not exist, this should not happen.
 119             continue;
 120         }
 121         $admins[$records[$id]->id] = $records[$id];
 122     }
 123
 124     return $admins;
 125 }
 126
 127 /**
 128  * Search through course users
 129  *
 130  * If $coursid specifies the site course then this function searches
 131  * through all undeleted and confirmed users
 132  *
 133  * @global object
 134  * @uses SITEID
 135  * @uses SQL_PARAMS_NAMED
 136  * @uses CONTEXT_COURSE
 137  * @param int $courseid The course in question.
 138  * @param int $groupid The group in question.
 139  * @param string $searchtext The string to search for
 140  * @param string $sort A field to sort by
 141  * @param array $exceptions A list of IDs to ignore, eg 2,4,5,8,9,10
 142  * @return array
 143  */
 144 function search_users($courseid, $groupid, $searchtext, $sort='', array $exceptions=null) {
 145     global $DB;
 146
 147     $fullname  = $DB->sql_fullname('u.firstname', 'u.lastname');
 148
 149     if (!empty($exceptions)) {
 150         list($exceptions, $params) = $DB->get_in_or_equal($exceptions, SQL_PARAMS_NAMED, 'ex', false);
 151         $except = "AND u.id $exceptions";
 152     } else {
 153         $except = "";
 154         $params = array();
 155     }
 156
 157     if (!empty($sort)) {
 158         $order = "ORDER BY $sort";
 159     } else {
 160         $order = "";
 161     }
 162
 163     $select = "u.deleted = 0 AND u.confirmed = 1 AND (".$DB->sql_like($fullname, ':search1', false)." OR ".$DB->sql_like('u.email', ':search2', false).")";
 164     $params['search1'] = "%$searchtext%";
 165     $params['search2'] = "%$searchtext%";
 166
 167     if (!$courseid or $courseid == SITEID) {
 168         $sql = "SELECT u.id, u.firstname, u.lastname, u.email
 169                   FROM {user} u
 170                  WHERE $select
 171                        $except
 172                 $order";
 173         return $DB->get_records_sql($sql, $params);
 174
 175     } else {
 176         if ($groupid) {
 177             $sql = "SELECT u.id, u.firstname, u.lastname, u.email
 178                       FROM {user} u
 179                       JOIN {groups_members} gm ON gm.userid = u.id
 180                      WHERE $select AND gm.groupid = :groupid
 181                            $except
 182                      $order";
 183             $params['groupid'] = $groupid;
 184             return $DB->get_records_sql($sql, $params);
 185
 186         } else {
 187             $context = context_course::instance($courseid);
 188
 189             // We want to query both the current context and parent contexts.
 190             list($relatedctxsql, $relatedctxparams) = $DB->get_in_or_equal($context->get_parent_context_ids(true), SQL_PARAMS_NAMED, 'relatedctx');
 191
 192             $sql = "SELECT u.id, u.firstname, u.lastname, u.email
 193                       FROM {user} u
 194                       JOIN {role_assignments} ra ON ra.userid = u.id
 195                      WHERE $select AND ra.contextid $relatedctxsql
 196                            $except
 197                     $order";
 198             $params = array_merge($params, $relatedctxparams);
 199             return $DB->get_records_sql($sql, $params);
 200         }
 201     }
 202 }
 203
 204 /**
 205  * Returns SQL used to search through user table to find users (in a query
 206  * which may also join and apply other conditions).
 207  *
 208  * You can combine this SQL with an existing query by adding 'AND $sql' to the
 209  * WHERE clause of your query (where $sql is the first element in the array
 210  * returned by this function), and merging in the $params array to the parameters
 211  * of your query (where $params is the second element). Your query should use
 212  * named parameters such as :param, rather than the question mark style.
 213  *
 214  * There are examples of basic usage in the unit test for this function.
 215  *
 216  * @param string $search the text to search for (empty string = find all)
 217  * @param string $u the table alias for the user table in the query being
 218  *     built. May be ''.
 219  * @param bool $searchanywhere If true (default), searches in the middle of
 220  *     names, otherwise only searches at start
 221  * @param array $extrafields Array of extra user fields to include in search
 222  * @param array $exclude Array of user ids to exclude (empty = don't exclude)
 223  * @param array $includeonly If specified, only returns users that have ids
 224  *     incldued in this array (empty = don't restrict)
 225  * @return array an array with two elements, a fragment of SQL to go in the
 226  *     where clause the query, and an associative array containing any required
 227  *     parameters (using named placeholders).
 228  */
 229 function users_search_sql($search, $u = 'u', $searchanywhere = true, array $extrafields = array(),
 230         array $exclude = null, array $includeonly = null) {
 231     global $DB, $CFG;
 232     $params = array();
 233     $tests = array();
 234
 235     if ($u) {
 236         $u .= '.';
 237     }
 238
 239     // If we have a $search string, put a field LIKE '$search%' condition on each field.
 240     if ($search) {
 241         $conditions = array(
 242             $DB->sql_fullname($u . 'firstname', $u . 'lastname'),
 243             $conditions[] = $u . 'lastname'
 244         );
 245         foreach ($extrafields as $field) {
 246             $conditions[] = $u . $field;
 247         }
 248         if ($searchanywhere) {
 249             $searchparam = '%' . $search . '%';
 250         } else {
 251             $searchparam = $search . '%';
 252         }
 253         $i = 0;
 254         foreach ($conditions as $key => $condition) {
 255             $conditions[$key] = $DB->sql_like($condition, ":con{$i}00", false, false);
 256             $params["con{$i}00"] = $searchparam;
 257             $i++;
 258         }
 259         $tests[] = '(' . implode(' OR ', $conditions) . ')';
 260     }
 261
 262     // Add some additional sensible conditions.
 263     $tests[] = $u . "id <> :guestid";
 264     $params['guestid'] = $CFG->siteguest;
 265     $tests[] = $u . 'deleted = 0';
 266     $tests[] = $u . 'confirmed = 1';
 267
 268     // If we are being asked to exclude any users, do that.
 269     if (!empty($exclude)) {
 270         list($usertest, $userparams) = $DB->get_in_or_equal($exclude, SQL_PARAMS_NAMED, 'ex', false);
 271         $tests[] = $u . 'id ' . $usertest;
 272         $params = array_merge($params, $userparams);
 273     }
 274
 275     // If we are validating a set list of userids, add an id IN (...) test.
 276     if (!empty($includeonly)) {
 277         list($usertest, $userparams) = $DB->get_in_or_equal($includeonly, SQL_PARAMS_NAMED, 'val');
 278         $tests[] = $u . 'id ' . $usertest;
 279         $params = array_merge($params, $userparams);
 280     }
 281
 282     // In case there are no tests, add one result (this makes it easier to combine
 283     // this with an existing query as you can always add AND $sql).
 284     if (empty($tests)) {
 285         $tests[] = '1 = 1';
 286     }
 287
 288     // Combing the conditions and return.
 289     return array(implode(' AND ', $tests), $params);
 290 }
 291
 292
 293 /**
 294  * This function generates the standard ORDER BY clause for use when generating
 295  * lists of users. If you don't have a reason to use a different order, then
 296  * you should use this method to generate the order when displaying lists of users.
 297  *
 298  * If the optional $search parameter is passed, then exact matches to the search
 299  * will be sorted first. For example, suppose you have two users 'Al Zebra' and
 300  * 'Alan Aardvark'. The default sort is Alan, then Al. If, however, you search for
 301  * 'Al', then Al will be listed first. (With two users, this is not a big deal,
 302  * but with thousands of users, it is essential.)
 303  *
 304  * The list of fields scanned for exact matches are:
 305  *  - firstname
 306  *  - lastname
 307  *  - $DB->sql_fullname
 308  *  - those returned by get_extra_user_fields
 309  *
 310  * If named parameters are used (which is the default, and highly recommended),
 311  * then the parameter names are like :usersortexactN, where N is an int.
 312  *
 313  * The simplest possible example use is:
 314  * list($sort, $params) = users_order_by_sql();
 315  * $sql = 'SELECT * FROM {users} ORDER BY ' . $sort;
 316  *
 317  * A more complex example, showing that this sort can be combined with other sorts:
 318  * list($sort, $sortparams) = users_order_by_sql('u');
 319  * $sql = "SELECT g.id AS groupid, gg.groupingid, u.id AS userid, u.firstname, u.lastname, u.idnumber, u.username
 320  *           FROM {groups} g
 321  *      LEFT JOIN {groupings_groups} gg ON g.id = gg.groupid
 322  *      LEFT JOIN {groups_members} gm ON g.id = gm.groupid
 323  *      LEFT JOIN {user} u ON gm.userid = u.id
 324  *          WHERE g.courseid = :courseid $groupwhere $groupingwhere
 325  *       ORDER BY g.name, $sort";
 326  * $params += $sortparams;
 327  *
 328  * An example showing the use of $search:
 329  * list($sort, $sortparams) = users_order_by_sql('u', $search, $this->get_context());
 330  * $order = ' ORDER BY ' . $sort;
 331  * $params += $sortparams;
 332  * $availableusers = $DB->get_records_sql($fields . $sql . $order, $params, $page*$perpage, $perpage);
 333  *
 334  * @param string $usertablealias (optional) any table prefix for the {users} table. E.g. 'u'.
 335  * @param string $search (optional) a current search string. If given,
 336  *      any exact matches to this string will be sorted first.
 337  * @param context $context the context we are in. Use by get_extra_user_fields.
 338  *      Defaults to $PAGE->context.
 339  * @return array with two elements:
 340  *      string SQL fragment to use in the ORDER BY clause. For example, "firstname, lastname".
 341  *      array of parameters used in the SQL fragment.
 342  */
 343 function users_order_by_sql($usertablealias = '', $search = null, context $context = null) {
 344     global $DB, $PAGE;
 345
 346     if ($usertablealias) {
 347         $tableprefix = $usertablealias . '.';
 348     } else {
 349         $tableprefix = '';
 350     }
 351
 352     $sort = "{$tableprefix}lastname, {$tableprefix}firstname, {$tableprefix}id";
 353     $params = array();
 354
 355     if (!$search) {
 356         return array($sort, $params);
 357     }
 358
 359     if (!$context) {
 360         $context = $PAGE->context;
 361     }
 362
 363     $exactconditions = array();
 364     $paramkey = 'usersortexact1';
 365
 366     $exactconditions[] = $DB->sql_fullname($tableprefix . 'firstname', $tableprefix  . 'lastname') .
 367             ' = :' . $paramkey;
 368     $params[$paramkey] = $search;
 369     $paramkey++;
 370
 371     $fieldstocheck = array_merge(array('firstname', 'lastname'), get_extra_user_fields($context));
 372     foreach ($fieldstocheck as $key => $field) {
 373         $exactconditions[] = 'LOWER(' . $tableprefix . $field . ') = LOWER(:' . $paramkey . ')';
 374         $params[$paramkey] = $search;
 375         $paramkey++;
 376     }
 377
 378     $sort = 'CASE WHEN ' . implode(' OR ', $exactconditions) .
 379             ' THEN 0 ELSE 1 END, ' . $sort;
 380
 381     return array($sort, $params);
 382 }
 383
 384 /**
 385  * Returns a subset of users
 386  *
 387  * @global object
 388  * @uses DEBUG_DEVELOPER
 389  * @uses SQL_PARAMS_NAMED
 390  * @param bool $get If false then only a count of the records is returned
 391  * @param string $search A simple string to search for
 392  * @param bool $confirmed A switch to allow/disallow unconfirmed users
 393  * @param array $exceptions A list of IDs to ignore, eg 2,4,5,8,9,10
 394  * @param string $sort A SQL snippet for the sorting criteria to use
 395  * @param string $firstinitial Users whose first name starts with $firstinitial
 396  * @param string $lastinitial Users whose last name starts with $lastinitial
 397  * @param string $page The page or records to return
 398  * @param string $recordsperpage The number of records to return per page
 399  * @param string $fields A comma separated list of fields to be returned from the chosen table.
 400  * @return array|int|bool  {@link $USER} records unless get is false in which case the integer count of the records found is returned.
 401  *                        False is returned if an error is encountered.
 402  */
 403 function get_users($get=true, $search='', $confirmed=false, array $exceptions=null, $sort='firstname ASC',
 404                    $firstinitial='', $lastinitial='', $page='', $recordsperpage='', $fields='*', $extraselect='', array $extraparams=null) {
 405     global $DB, $CFG;
 406
 407     if ($get && !$recordsperpage) {
 408         debugging('Call to get_users with $get = true no $recordsperpage limit. ' .
 409                 'On large installations, this will probably cause an out of memory error. ' .
 410                 'Please think again and change your code so that it does not try to ' .
 411                 'load so much data into memory.', DEBUG_DEVELOPER);
 412     }
 413
 414     $fullname  = $DB->sql_fullname();
 415
 416     $select = " id <> :guestid AND deleted = 0";
 417     $params = array('guestid'=>$CFG->siteguest);
 418
 419     if (!empty($search)){
 420         $search = trim($search);
 421         $select .= " AND (".$DB->sql_like($fullname, ':search1', false)." OR ".$DB->sql_like('email', ':search2', false)." OR username = :search3)";
 422         $params['search1'] = "%$search%";
 423         $params['search2'] = "%$search%";
 424         $params['search3'] = "$search";
 425     }
 426
 427     if ($confirmed) {
 428         $select .= " AND confirmed = 1";
 429     }
 430
 431     if ($exceptions) {
 432         list($exceptions, $eparams) = $DB->get_in_or_equal($exceptions, SQL_PARAMS_NAMED, 'ex', false);
 433         $params = $params + $eparams;
 434         $select .= " AND id $exceptions";
 435     }
 436
 437     if ($firstinitial) {
 438         $select .= " AND ".$DB->sql_like('firstname', ':fni', false, false);
 439         $params['fni'] = "$firstinitial%";
 440     }
 441     if ($lastinitial) {
 442         $select .= " AND ".$DB->sql_like('lastname', ':lni', false, false);
 443         $params['lni'] = "$lastinitial%";
 444     }
 445
 446     if ($extraselect) {
 447         $select .= " AND $extraselect";
 448         $params = $params + (array)$extraparams;
 449     }
 450
 451     if ($get) {
 452         return $DB->get_records_select('user', $select, $params, $sort, $fields, $page, $recordsperpage);
 453     } else {
 454         return $DB->count_records_select('user', $select, $params);
 455     }
 456 }
 457
 458
 459 /**
 460  * Return filtered (if provided) list of users in site, except guest and deleted users.
 461  *
 462  * @param string $sort An SQL field to sort by
 463  * @param string $dir The sort direction ASC|DESC
 464  * @param int $page The page or records to return
 465  * @param int $recordsperpage The number of records to return per page
 466  * @param string $search A simple string to search for
 467  * @param string $firstinitial Users whose first name starts with $firstinitial
 468  * @param string $lastinitial Users whose last name starts with $lastinitial
 469  * @param string $extraselect An additional SQL select statement to append to the query
 470  * @param array $extraparams Additional parameters to use for the above $extraselect
 471  * @param stdClass $extracontext If specified, will include user 'extra fields'
 472  *   as appropriate for current user and given context
 473  * @return array Array of {@link $USER} records
 474  */
 475 function get_users_listing($sort='lastaccess', $dir='ASC', $page=0, $recordsperpage=0,
 476                            $search='', $firstinitial='', $lastinitial='', $extraselect='',
 477                            array $extraparams=null, $extracontext = null) {
 478     global $DB, $CFG;
 479
 480     $fullname  = $DB->sql_fullname();
 481
 482     $select = "deleted <> 1 AND id <> :guestid";
 483     $params = array('guestid' => $CFG->siteguest);
 484
 485     if (!empty($search)) {
 486         $search = trim($search);
 487         $select .= " AND (". $DB->sql_like($fullname, ':search1', false, false).
 488                    " OR ". $DB->sql_like('email', ':search2', false, false).
 489                    " OR username = :search3)";
 490         $params['search1'] = "%$search%";
 491         $params['search2'] = "%$search%";
 492         $params['search3'] = "$search";
 493     }
 494
 495     if ($firstinitial) {
 496         $select .= " AND ". $DB->sql_like('firstname', ':fni', false, false);
 497         $params['fni'] = "$firstinitial%";
 498     }
 499     if ($lastinitial) {
 500         $select .= " AND ". $DB->sql_like('lastname', ':lni', false, false);
 501         $params['lni'] = "$lastinitial%";
 502     }
 503
 504     if ($extraselect) {
 505         $select .= " AND $extraselect";
 506         $params = $params + (array)$extraparams;
 507     }
 508
 509     if ($sort) {
 510         $sort = " ORDER BY $sort $dir";
 511     }
 512
 513     // If a context is specified, get extra user fields that the current user
 514     // is supposed to see.
 515     $extrafields = '';
 516     if ($extracontext) {
 517         $extrafields = get_extra_user_fields_sql($extracontext, '', '',
 518                 array('id', 'username', 'email', 'firstname', 'lastname', 'city', 'country',
 519                 'lastaccess', 'confirmed', 'mnethostid'));
 520     }
 521     $namefields = get_all_user_name_fields(true);
 522     $extrafields = "$extrafields, $namefields";
 523
 524     // warning: will return UNCONFIRMED USERS
 525     return $DB->get_records_sql("SELECT id, username, email, city, country, lastaccess, confirmed, mnethostid, suspended $extrafields
 526                                    FROM {user}
 527                                   WHERE $select
 528                                   $sort", $params, $page, $recordsperpage);
 529
 530 }
 531
 532
 533 /**
 534  * Full list of users that have confirmed their accounts.
 535  *
 536  * @global object
 537  * @return array of unconfirmed users
 538  */
 539 function get_users_confirmed() {
 540     global $DB, $CFG;
 541     return $DB->get_records_sql("SELECT *
 542                                    FROM {user}
 543                                   WHERE confirmed = 1 AND deleted = 0 AND id <> ?", array($CFG->siteguest));
 544 }
 545
 546
 547 /// OTHER SITE AND COURSE FUNCTIONS /////////////////////////////////////////////
 548
 549
 550 /**
 551  * Returns $course object of the top-level site.
 552  *
 553  * @return object A {@link $COURSE} object for the site, exception if not found
 554  */
 555 function get_site() {
 556     global $SITE, $DB;
 557
 558     if (!empty($SITE->id)) {   // We already have a global to use, so return that
 559         return $SITE;
 560     }
 561
 562     if ($course = $DB->get_record('course', array('category'=>0))) {
 563         return $course;
 564     } else {
 565         // course table exists, but the site is not there,
 566         // unfortunately there is no automatic way to recover
 567         throw new moodle_exception('nosite', 'error');
 568     }
 569 }
 570
 571 /**
 572  * Gets a course object from database. If the course id corresponds to an
 573  * already-loaded $COURSE or $SITE object, then the loaded object will be used,
 574  * saving a database query.
 575  *
 576  * If it reuses an existing object, by default the object will be cloned. This
 577  * means you can modify the object safely without affecting other code.
 578  *
 579  * @param int $courseid Course id
 580  * @param bool $clone If true (default), makes a clone of the record
 581  * @return stdClass A course object
 582  * @throws dml_exception If not found in database
 583  */
 584 function get_course($courseid, $clone = true) {
 585     global $DB, $COURSE, $SITE;
 586     if (!empty($COURSE->id) && $COURSE->id == $courseid) {
 587         return $clone ? clone($COURSE) : $COURSE;
 588     } else if (!empty($SITE->id) && $SITE->id == $courseid) {
 589         return $clone ? clone($SITE) : $SITE;
 590     } else {
 591         return $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST);
 592     }
 593 }
 594
 595 /**
 596  * Returns list of courses, for whole site, or category
 597  *
 598  * Returns list of courses, for whole site, or category
 599  * Important: Using c.* for fields is extremely expensive because
 600  *            we are using distinct. You almost _NEVER_ need all the fields
 601  *            in such a large SELECT
 602  *
 603  * Consider using core_course_category::get_courses()
 604  * or core_course_category::search_courses() instead since they use caching.
 605  *
 606  * @global object
 607  * @global object
 608  * @global object
 609  * @uses CONTEXT_COURSE
 610  * @param string|int $categoryid Either a category id or 'all' for everything
 611  * @param string $sort A field and direction to sort by
 612  * @param string $fields The additional fields to return (note that "id, category, visible" are always present)
 613  * @return array Array of courses
 614  */
 615 function get_courses($categoryid="all", $sort="c.sortorder ASC", $fields="c.*") {
 616
 617     global $USER, $CFG, $DB;
 618
 619     $params = array();
 620
 621     if ($categoryid !== "all" && is_numeric($categoryid)) {
 622         $categoryselect = "WHERE c.category = :catid";
 623         $params['catid'] = $categoryid;
 624     } else {
 625         $categoryselect = "";
 626     }
 627
 628     if (empty($sort)) {
 629         $sortstatement = "";
 630     } else {
 631         $sortstatement = "ORDER BY $sort";
 632     }
 633
 634     $visiblecourses = array();
 635
 636     $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
 637     $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
 638     $params['contextlevel'] = CONTEXT_COURSE;
 639
 640     // The fields "id, category, visible" are required in the subsequent loop and must always be present.
 641     if ($fields !== 'c.*') {
 642         $fieldarray = array_merge(
 643             // Split fields on comma + zero or more whitespace, merge with required fields.
 644             preg_split('/,\s*/', $fields), [
 645                 'c.id',
 646                 'c.category',
 647                 'c.visible',
 648             ]
 649         );
 650         $fields = implode(',', array_unique($fieldarray));
 651     }
 652
 653     $sql = "SELECT $fields $ccselect
 654               FROM {course} c
 655            $ccjoin
 656               $categoryselect
 657               $sortstatement";
 658
 659     // pull out all course matching the cat
 660     if ($courses = $DB->get_records_sql($sql, $params)) {
 661
 662         // loop throught them
 663         foreach ($courses as $course) {
 664             context_helper::preload_from_record($course);
 665             if (core_course_category::can_view_course_info($course)) {
 666                 $visiblecourses [$course->id] = $course;
 667             }
 668         }
 669     }
 670     return $visiblecourses;
 671 }
 672
 673 /**
 674  * A list of courses that match a search
 675  *
 676  * @global object
 677  * @global object
 678  * @param array $searchterms An array of search criteria
 679  * @param string $sort A field and direction to sort by
 680  * @param int $page The page number to get
 681  * @param int $recordsperpage The number of records per page
 682  * @param int $totalcount Passed in by reference.
 683  * @param array $requiredcapabilities Extra list of capabilities used to filter courses
 684  * @param array $searchcond additional search conditions, for example ['c.enablecompletion = :p1']
 685  * @param array $params named parameters for additional search conditions, for example ['p1' => 1]
 686  * @return stdClass[] {@link $COURSE} records
 687  */
 688 function get_courses_search($searchterms, $sort, $page, $recordsperpage, &$totalcount,
 689                             $requiredcapabilities = array(), $searchcond = [], $params = []) {
 690     global $CFG, $DB;
 691
 692     if ($DB->sql_regex_supported()) {
 693         $REGEXP    = $DB->sql_regex(true);
 694         $NOTREGEXP = $DB->sql_regex(false);
 695     }
 696
 697     $i = 0;
 698
 699     // Thanks Oracle for your non-ansi concat and type limits in coalesce. MDL-29912
 700     if ($DB->get_dbfamily() == 'oracle') {
 701         $concat = "(c.summary|| ' ' || c.fullname || ' ' || c.idnumber || ' ' || c.shortname)";
 702     } else {
 703         $concat = $DB->sql_concat("COALESCE(c.summary, '')", "' '", 'c.fullname', "' '", 'c.idnumber', "' '", 'c.shortname');
 704     }
 705
 706     foreach ($searchterms as $searchterm) {
 707         $i++;
 708
 709         $NOT = false; /// Initially we aren't going to perform NOT LIKE searches, only MSSQL and Oracle
 710                    /// will use it to simulate the "-" operator with LIKE clause
 711
 712     /// Under Oracle and MSSQL, trim the + and - operators and perform
 713     /// simpler LIKE (or NOT LIKE) queries
 714         if (!$DB->sql_regex_supported()) {
 715             if (substr($searchterm, 0, 1) == '-') {
 716                 $NOT = true;
 717             }
 718             $searchterm = trim($searchterm, '+-');
 719         }
 720
 721         // TODO: +- may not work for non latin languages
 722
 723         if (substr($searchterm,0,1) == '+') {
 724             $searchterm = trim($searchterm, '+-');
 725             $searchterm = preg_quote($searchterm, '|');
 726             $searchcond[] = "$concat $REGEXP :ss$i";
 727             $params['ss'.$i] = "(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)";
 728
 729         } else if ((substr($searchterm,0,1) == "-") && (core_text::strlen($searchterm) > 1)) {
 730             $searchterm = trim($searchterm, '+-');
 731             $searchterm = preg_quote($searchterm, '|');
 732             $searchcond[] = "$concat $NOTREGEXP :ss$i";
 733             $params['ss'.$i] = "(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)";
 734
 735         } else {
 736             $searchcond[] = $DB->sql_like($concat,":ss$i", false, true, $NOT);
 737             $params['ss'.$i] = "%$searchterm%";
 738         }
 739     }
 740
 741     if (empty($searchcond)) {
 742         $searchcond = array('1 = 1');
 743     }
 744
 745     $searchcond = implode(" AND ", $searchcond);
 746
 747     $courses = array();
 748     $c = 0; // counts how many visible courses we've seen
 749
 750     // Tiki pagination
 751     $limitfrom = $page * $recordsperpage;
 752     $limitto   = $limitfrom + $recordsperpage;
 753
 754     $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
 755     $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
 756     $params['contextlevel'] = CONTEXT_COURSE;
 757
 758     $sql = "SELECT c.* $ccselect
 759               FROM {course} c
 760            $ccjoin
 761              WHERE $searchcond AND c.id <> ".SITEID."
 762           ORDER BY $sort";
 763
 764     $mycourses = enrol_get_my_courses();
 765     $rs = $DB->get_recordset_sql($sql, $params);
 766     foreach($rs as $course) {
 767         // Preload contexts only for hidden courses or courses we need to return.
 768         context_helper::preload_from_record($course);
 769         $coursecontext = context_course::instance($course->id);
 770         if (!array_key_exists($course->id, $mycourses) && !core_course_category::can_view_course_info($course)) {
 771             continue;
 772         }
 773         if (!empty($requiredcapabilities)) {
 774             if (!has_all_capabilities($requiredcapabilities, $coursecontext)) {
 775                 continue;
 776             }
 777         }
 778         // Don't exit this loop till the end
 779         // we need to count all the visible courses
 780         // to update $totalcount
 781         if ($c >= $limitfrom && $c < $limitto) {
 782             $courses[$course->id] = $course;
 783         }
 784         $c++;
 785     }
 786     $rs->close();
 787
 788     // our caller expects 2 bits of data - our return
 789     // array, and an updated $totalcount
 790     $totalcount = $c;
 791     return $courses;
 792 }
 793
 794 /**
 795  * Fixes course category and course sortorder, also verifies category and course parents and paths.
 796  * (circular references are not fixed)
 797  *
 798  * @global object
 799  * @global object
 800  * @uses MAX_COURSE_CATEGORIES
 801  * @uses SITEID
 802  * @uses CONTEXT_COURSE
 803  * @return void
 804  */
 805 function fix_course_sortorder() {
 806     global $DB, $SITE;
 807
 808     //WARNING: this is PHP5 only code!
 809
 810     // if there are any changes made to courses or categories we will trigger
 811     // the cache events to purge all cached courses/categories data
 812     $cacheevents = array();
 813
 814     if ($unsorted = $DB->get_records('course_categories', array('sortorder'=>0))) {
 815         //move all categories that are not sorted yet to the end
 816         $DB->set_field('course_categories', 'sortorder',
 817             get_max_courses_in_category() * MAX_COURSE_CATEGORIES, array('sortorder' => 0));
 818         $cacheevents['changesincoursecat'] = true;
 819     }
 820
 821     $allcats = $DB->get_records('course_categories', null, 'sortorder, id', 'id, sortorder, parent, depth, path');
 822     $topcats    = array();
 823     $brokencats = array();
 824     foreach ($allcats as $cat) {
 825         $sortorder = (int)$cat->sortorder;
 826         if (!$cat->parent) {
 827             while(isset($topcats[$sortorder])) {
 828                 $sortorder++;
 829             }
 830             $topcats[$sortorder] = $cat;
 831             continue;
 832         }
 833         if (!isset($allcats[$cat->parent])) {
 834             $brokencats[] = $cat;
 835             continue;
 836         }
 837         if (!isset($allcats[$cat->parent]->children)) {
 838             $allcats[$cat->parent]->children = array();
 839         }
 840         while(isset($allcats[$cat->parent]->children[$sortorder])) {
 841             $sortorder++;
 842         }
 843         $allcats[$cat->parent]->children[$sortorder] = $cat;
 844     }
 845     unset($allcats);
 846
 847     // add broken cats to category tree
 848     if ($brokencats) {
 849         $defaultcat = reset($topcats);
 850         foreach ($brokencats as $cat) {
 851             $topcats[] = $cat;
 852         }
 853     }
 854
 855     // now walk recursively the tree and fix any problems found
 856     $sortorder = 0;
 857     $fixcontexts = array();
 858     if (_fix_course_cats($topcats, $sortorder, 0, 0, '', $fixcontexts)) {
 859         $cacheevents['changesincoursecat'] = true;
 860     }
 861
 862     // detect if there are "multiple" frontpage courses and fix them if needed
 863     $frontcourses = $DB->get_records('course', array('category'=>0), 'id');
 864     if (count($frontcourses) > 1) {
 865         if (isset($frontcourses[SITEID])) {
 866             $frontcourse = $frontcourses[SITEID];
 867             unset($frontcourses[SITEID]);
 868         } else {
 869             $frontcourse = array_shift($frontcourses);
 870         }
 871         $defaultcat = reset($topcats);
 872         foreach ($frontcourses as $course) {
 873             $DB->set_field('course', 'category', $defaultcat->id, array('id'=>$course->id));
 874             $context = context_course::instance($course->id);
 875             $fixcontexts[$context->id] = $context;
 876             $cacheevents['changesincourse'] = true;
 877         }
 878         unset($frontcourses);
 879     } else {
 880         $frontcourse = reset($frontcourses);
 881     }
 882
 883     // now fix the paths and depths in context table if needed
 884     if ($fixcontexts) {
 885         foreach ($fixcontexts as $fixcontext) {
 886             $fixcontext->reset_paths(false);
 887         }
 888         context_helper::build_all_paths(false);
 889         unset($fixcontexts);
 890         $cacheevents['changesincourse'] = true;
 891         $cacheevents['changesincoursecat'] = true;
 892     }
 893
 894     // release memory
 895     unset($topcats);
 896     unset($brokencats);
 897     unset($fixcontexts);
 898
 899     // fix frontpage course sortorder
 900     if ($frontcourse->sortorder != 1) {
 901         $DB->set_field('course', 'sortorder', 1, array('id'=>$frontcourse->id));
 902         $cacheevents['changesincourse'] = true;
 903     }
 904
 905     // now fix the course counts in category records if needed
 906     $sql = "SELECT cc.id, cc.coursecount, COUNT(c.id) AS newcount
 907               FROM {course_categories} cc
 908               LEFT JOIN {course} c ON c.category = cc.id
 909           GROUP BY cc.id, cc.coursecount
 910             HAVING cc.coursecount <> COUNT(c.id)";
 911
 912     if ($updatecounts = $DB->get_records_sql($sql)) {
 913         // categories with more courses than MAX_COURSES_IN_CATEGORY
 914         $categories = array();
 915         foreach ($updatecounts as $cat) {
 916             $cat->coursecount = $cat->newcount;
 917             if ($cat->coursecount >= get_max_courses_in_category()) {
 918                 $categories[] = $cat->id;
 919             }
 920             unset($cat->newcount);
 921             $DB->update_record_raw('course_categories', $cat, true);
 922         }
 923         if (!empty($categories)) {
 924             $str = implode(', ', $categories);
 925             debugging("The number of courses (category id: $str) has reached max number of courses " .
 926                 "in a category (" . get_max_courses_in_category() . "). It will cause a sorting performance issue. " .
 927                 "Please set higher value for \$CFG->maxcoursesincategory in config.php. " .
 928                 "Please also make sure \$CFG->maxcoursesincategory * MAX_COURSE_CATEGORIES less than max integer. " .
 929                 "See tracker issues: MDL-25669 and MDL-69573", DEBUG_DEVELOPER);
 930         }
 931         $cacheevents['changesincoursecat'] = true;
 932     }
 933
 934     // now make sure that sortorders in course table are withing the category sortorder ranges
 935     $sql = "SELECT DISTINCT cc.id, cc.sortorder
 936               FROM {course_categories} cc
 937               JOIN {course} c ON c.category = cc.id
 938              WHERE c.sortorder < cc.sortorder OR c.sortorder > cc.sortorder + " . get_max_courses_in_category();
 939
 940     if ($fixcategories = $DB->get_records_sql($sql)) {
 941         //fix the course sortorder ranges
 942         foreach ($fixcategories as $cat) {
 943             $sql = "UPDATE {course}
 944                        SET sortorder = ".$DB->sql_modulo('sortorder', get_max_courses_in_category())." + ?
 945                      WHERE category = ?";
 946             $DB->execute($sql, array($cat->sortorder, $cat->id));
 947         }
 948         $cacheevents['changesincoursecat'] = true;
 949     }
 950     unset($fixcategories);
 951
 952     // categories having courses with sortorder duplicates or having gaps in sortorder
 953     $sql = "SELECT DISTINCT c1.category AS id , cc.sortorder
 954               FROM {course} c1
 955               JOIN {course} c2 ON c1.sortorder = c2.sortorder
 956               JOIN {course_categories} cc ON (c1.category = cc.id)
 957              WHERE c1.id <> c2.id";
 958     $fixcategories = $DB->get_records_sql($sql);
 959
 960     $sql = "SELECT cc.id, cc.sortorder, cc.coursecount, MAX(c.sortorder) AS maxsort, MIN(c.sortorder) AS minsort
 961               FROM {course_categories} cc
 962               JOIN {course} c ON c.category = cc.id
 963           GROUP BY cc.id, cc.sortorder, cc.coursecount
 964             HAVING (MAX(c.sortorder) <>  cc.sortorder + cc.coursecount) OR (MIN(c.sortorder) <>  cc.sortorder + 1)";
 965     $gapcategories = $DB->get_records_sql($sql);
 966
 967     foreach ($gapcategories as $cat) {
 968         if (isset($fixcategories[$cat->id])) {
 969             // duplicates detected already
 970
 971         } else if ($cat->minsort == $cat->sortorder and $cat->maxsort == $cat->sortorder + $cat->coursecount - 1) {
 972             // easy - new course inserted with sortorder 0, the rest is ok
 973             $sql = "UPDATE {course}
 974                        SET sortorder = sortorder + 1
 975                      WHERE category = ?";
 976             $DB->execute($sql, array($cat->id));
 977
 978         } else {
 979             // it needs full resorting
 980             $fixcategories[$cat->id] = $cat;
 981         }
 982         $cacheevents['changesincourse'] = true;
 983     }
 984     unset($gapcategories);
 985
 986     // fix course sortorders in problematic categories only
 987     foreach ($fixcategories as $cat) {
 988         $i = 1;
 989         $courses = $DB->get_records('course', array('category'=>$cat->id), 'sortorder ASC, id DESC', 'id, sortorder');
 990         foreach ($courses as $course) {
 991             if ($course->sortorder != $cat->sortorder + $i) {
 992                 $course->sortorder = $cat->sortorder + $i;
 993                 $DB->update_record_raw('course', $course, true);
 994                 $cacheevents['changesincourse'] = true;
 995             }
 996             $i++;
 997         }
 998     }
 999
1000     // advise all caches that need to be rebuilt
1001     foreach (array_keys($cacheevents) as $event) {
1002         cache_helper::purge_by_event($event);
1003     }
1004 }
1005
1006 /**
1007  * Internal recursive category verification function, do not use directly!
1008  *
1009  * @todo Document the arguments of this function better
1010  *
1011  * @global object
1012  * @uses CONTEXT_COURSECAT
1013  * @param array $children
1014  * @param int $sortorder
1015  * @param string $parent
1016  * @param int $depth
1017  * @param string $path
1018  * @param array $fixcontexts
1019  * @return bool if changes were made
1020  */
1021 function _fix_course_cats($children, &$sortorder, $parent, $depth, $path, &$fixcontexts) {
1022     global $DB;
1023
1024     $depth++;
1025     $changesmade = false;
1026
1027     foreach ($children as $cat) {
1028         $sortorder = $sortorder + get_max_courses_in_category();
1029         $update = false;
1030         if ($parent != $cat->parent or $depth != $cat->depth or $path.'/'.$cat->id != $cat->path) {
1031             $cat->parent = $parent;
1032             $cat->depth  = $depth;
1033             $cat->path   = $path.'/'.$cat->id;
1034             $update = true;
1035
1036             // make sure context caches are rebuild and dirty contexts marked
1037             $context = context_coursecat::instance($cat->id);
1038             $fixcontexts[$context->id] = $context;
1039         }
1040         if ($cat->sortorder != $sortorder) {
1041             $cat->sortorder = $sortorder;
1042             $update = true;
1043         }
1044         if ($update) {
1045             $DB->update_record('course_categories', $cat, true);
1046             $changesmade = true;
1047         }
1048         if (isset($cat->children)) {
1049             if (_fix_course_cats($cat->children, $sortorder, $cat->id, $cat->depth, $cat->path, $fixcontexts)) {
1050                 $changesmade = true;
1051             }
1052         }
1053     }
1054     return $changesmade;
1055 }
1056
1057 /**
1058  * List of remote courses that a user has access to via MNET.
1059  * Works only on the IDP
1060  *
1061  * @global object
1062  * @global object
1063  * @param int @userid The user id to get remote courses for
1064  * @return array Array of {@link $COURSE} of course objects
1065  */
1066 function get_my_remotecourses($userid=0) {
1067     global $DB, $USER;
1068
1069     if (empty($userid)) {
1070         $userid = $USER->id;
1071     }
1072
1073     // we can not use SELECT DISTINCT + text field (summary) because of MS SQL and Oracle, subselect used therefore
1074     $sql = "SELECT c.id, c.remoteid, c.shortname, c.fullname,
1075                    c.hostid, c.summary, c.summaryformat, c.categoryname AS cat_name,
1076                    h.name AS hostname
1077               FROM {mnetservice_enrol_courses} c
1078               JOIN (SELECT DISTINCT hostid, remotecourseid
1079                       FROM {mnetservice_enrol_enrolments}
1080                      WHERE userid = ?
1081                    ) e ON (e.hostid = c.hostid AND e.remotecourseid = c.remoteid)
1082               JOIN {mnet_host} h ON h.id = c.hostid";
1083
1084     return $DB->get_records_sql($sql, array($userid));
1085 }
1086
1087 /**
1088  * List of remote hosts that a user has access to via MNET.
1089  * Works on the SP
1090  *
1091  * @global object
1092  * @global object
1093  * @return array|bool Array of host objects or false
1094  */
1095 function get_my_remotehosts() {
1096     global $CFG, $USER;
1097
1098     if ($USER->mnethostid == $CFG->mnet_localhost_id) {
1099         return false; // Return nothing on the IDP
1100     }
1101     if (!empty($USER->mnet_foreign_host_array) && is_array($USER->mnet_foreign_host_array)) {
1102         return $USER->mnet_foreign_host_array;
1103     }
1104     return false;
1105 }
1106
1107
1108 /**
1109  * Returns a menu of all available scales from the site as well as the given course
1110  *
1111  * @global object
1112  * @param int $courseid The id of the course as found in the 'course' table.
1113  * @return array
1114  */
1115 function get_scales_menu($courseid=0) {
1116     global $DB;
1117
1118     $sql = "SELECT id, name, courseid
1119               FROM {scale}
1120              WHERE courseid = 0 or courseid = ?
1121           ORDER BY courseid ASC, name ASC";
1122     $params = array($courseid);
1123     $scales = array();
1124     $results = $DB->get_records_sql($sql, $params);
1125     foreach ($results as $index => $record) {
1126         $context = empty($record->courseid) ? context_system::instance() : context_course::instance($record->courseid);
1127         $scales[$index] = format_string($record->name, false, ["context" => $context]);
1128     }
1129     // Format: [id => 'scale name'].
1130     return $scales;
1131 }
1132
1133 /**
1134  * Increment standard revision field.
1135  *
1136  * The revision are based on current time and are incrementing.
1137  * There is a protection for runaway revisions, it may not go further than
1138  * one hour into future.
1139  *
1140  * The field has to be XMLDB_TYPE_INTEGER with size 10.
1141  *
1142  * @param string $table
1143  * @param string $field name of the field containing revision
1144  * @param string $select use empty string when updating all records
1145  * @param array $params optional select parameters
1146  */
1147 function increment_revision_number($table, $field, $select, array $params = null) {
1148     global $DB;
1149
1150     $now = time();
1151     $sql = "UPDATE {{$table}}
1152                    SET $field = (CASE
1153                        WHEN $field IS NULL THEN $now
1154                        WHEN $field < $now THEN $now
1155                        WHEN $field > $now + 3600 THEN $now
1156                        ELSE $field + 1 END)";
1157     if ($select) {
1158         $sql = $sql . " WHERE $select";
1159     }
1160     $DB->execute($sql, $params);
1161 }
1162
1163
1164 /// MODULE FUNCTIONS /////////////////////////////////////////////////
1165
1166 /**
1167  * Just gets a raw list of all modules in a course
1168  *
1169  * @global object
1170  * @param int $courseid The id of the course as found in the 'course' table.
1171  * @return array
1172  */
1173 function get_course_mods($courseid) {
1174     global $DB;
1175
1176     if (empty($courseid)) {
1177         return false; // avoid warnings
1178     }
1179
1180     return $DB->get_records_sql("SELECT cm.*, m.name as modname
1181                                    FROM {modules} m, {course_modules} cm
1182                                   WHERE cm.course = ? AND cm.module = m.id AND m.visible = 1",
1183                                 array($courseid)); // no disabled mods
1184 }
1185
1186
1187 /**
1188  * Given an id of a course module, finds the coursemodule description
1189  *
1190  * Please note that this function performs 1-2 DB queries. When possible use cached
1191  * course modinfo. For example get_fast_modinfo($courseorid)->get_cm($cmid)
1192  * See also {@link cm_info::get_course_module_record()}
1193  *
1194  * @global object
1195  * @param string $modulename name of module type, eg. resource, assignment,... (optional, slower and less safe if not specified)
1196  * @param int $cmid course module id (id in course_modules table)
1197  * @param int $courseid optional course id for extra validation
1198  * @param bool $sectionnum include relative section number (0,1,2 ...)
1199  * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
1200  *                        IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
1201  *                        MUST_EXIST means throw exception if no record or multiple records found
1202  * @return stdClass
1203  */
1204 function get_coursemodule_from_id($modulename, $cmid, $courseid=0, $sectionnum=false, $strictness=IGNORE_MISSING) {
1205     global $DB;
1206
1207     $params = array('cmid'=>$cmid);
1208
1209     if (!$modulename) {
1210         if (!$modulename = $DB->get_field_sql("SELECT md.name
1211                                                  FROM {modules} md
1212                                                  JOIN {course_modules} cm ON cm.module = md.id
1213                                                 WHERE cm.id = :cmid", $params, $strictness)) {
1214             return false;
1215         }
1216     } else {
1217         if (!core_component::is_valid_plugin_name('mod', $modulename)) {
1218             throw new coding_exception('Invalid modulename parameter');
1219         }
1220     }
1221
1222     $params['modulename'] = $modulename;
1223
1224     $courseselect = "";
1225     $sectionfield = "";
1226     $sectionjoin  = "";
1227
1228     if ($courseid) {
1229         $courseselect = "AND cm.course = :courseid";
1230         $params['courseid'] = $courseid;
1231     }
1232
1233     if ($sectionnum) {
1234         $sectionfield = ", cw.section AS sectionnum";
1235         $sectionjoin  = "LEFT JOIN {course_sections} cw ON cw.id = cm.section";
1236     }
1237
1238     $sql = "SELECT cm.*, m.name, md.name AS modname $sectionfield
1239               FROM {course_modules} cm
1240                    JOIN {modules} md ON md.id = cm.module
1241                    JOIN {".$modulename."} m ON m.id = cm.instance
1242                    $sectionjoin
1243              WHERE cm.id = :cmid AND md.name = :modulename
1244                    $courseselect";
1245
1246     return $DB->get_record_sql($sql, $params, $strictness);
1247 }
1248
1249 /**
1250  * Given an instance number of a module, finds the coursemodule description
1251  *
1252  * Please note that this function performs DB query. When possible use cached course
1253  * modinfo. For example get_fast_modinfo($courseorid)->instances[$modulename][$instance]
1254  * See also {@link cm_info::get_course_module_record()}
1255  *
1256  * @global object
1257  * @param string $modulename name of module type, eg. resource, assignment,...
1258  * @param int $instance module instance number (id in resource, assignment etc. table)
1259  * @param int $courseid optional course id for extra validation
1260  * @param bool $sectionnum include relative section number (0,1,2 ...)
1261  * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
1262  *                        IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
1263  *                        MUST_EXIST means throw exception if no record or multiple records found
1264  * @return stdClass
1265  */
1266 function get_coursemodule_from_instance($modulename, $instance, $courseid=0, $sectionnum=false, $strictness=IGNORE_MISSING) {
1267     global $DB;
1268
1269     if (!core_component::is_valid_plugin_name('mod', $modulename)) {
1270         throw new coding_exception('Invalid modulename parameter');
1271     }
1272
1273     $params = array('instance'=>$instance, 'modulename'=>$modulename);
1274
1275     $courseselect = "";
1276     $sectionfield = "";
1277     $sectionjoin  = "";
1278
1279     if ($courseid) {
1280         $courseselect = "AND cm.course = :courseid";
1281         $params['courseid'] = $courseid;
1282     }
1283
1284     if ($sectionnum) {
1285         $sectionfield = ", cw.section AS sectionnum";
1286         $sectionjoin  = "LEFT JOIN {course_sections} cw ON cw.id = cm.section";
1287     }
1288
1289     $sql = "SELECT cm.*, m.name, md.name AS modname $sectionfield
1290               FROM {course_modules} cm
1291                    JOIN {modules} md ON md.id = cm.module
1292                    JOIN {".$modulename."} m ON m.id = cm.instance
1293                    $sectionjoin
1294              WHERE m.id = :instance AND md.name = :modulename
1295                    $courseselect";
1296
1297     return $DB->get_record_sql($sql, $params, $strictness);
1298 }
1299
1300 /**
1301  * Returns all course modules of given activity in course
1302  *
1303  * @param string $modulename The module name (forum, quiz, etc.)
1304  * @param int $courseid The course id to get modules for
1305  * @param string $extrafields extra fields starting with m.
1306  * @return array Array of results
1307  */
1308 function get_coursemodules_in_course($modulename, $courseid, $extrafields='') {
1309     global $DB;
1310
1311     if (!core_component::is_valid_plugin_name('mod', $modulename)) {
1312         throw new coding_exception('Invalid modulename parameter');
1313     }
1314
1315     if (!empty($extrafields)) {
1316         $extrafields = ", $extrafields";
1317     }
1318     $params = array();
1319     $params['courseid'] = $courseid;
1320     $params['modulename'] = $modulename;
1321
1322
1323     return $DB->get_records_sql("SELECT cm.*, m.name, md.name as modname $extrafields
1324                                    FROM {course_modules} cm, {modules} md, {".$modulename."} m
1325                                   WHERE cm.course = :courseid AND
1326                                         cm.instance = m.id AND
1327                                         md.name = :modulename AND
1328                                         md.id = cm.module", $params);
1329 }
1330
1331 /**
1332  * Returns an array of all the active instances of a particular module in given courses, sorted in the order they are defined
1333  *
1334  * Returns an array of all the active instances of a particular
1335  * module in given courses, sorted in the order they are defined
1336  * in the course. Returns an empty array on any errors.
1337  *
1338  * The returned objects includle the columns cw.section, cm.visible,
1339  * cm.groupmode, and cm.groupingid, and are indexed by cm.id.
1340  *
1341  * @global object
1342  * @global object
1343  * @param string $modulename The name of the module to get instances for
1344  * @param array $courses an array of course objects.
1345  * @param int $userid
1346  * @param int $includeinvisible
1347  * @return array of module instance objects, including some extra fields from the course_modules
1348  *          and course_sections tables, or an empty array if an error occurred.
1349  */
1350 function get_all_instances_in_courses($modulename, $courses, $userid=NULL, $includeinvisible=false) {
1351     global $CFG, $DB;
1352
1353     if (!core_component::is_valid_plugin_name('mod', $modulename)) {
1354         throw new coding_exception('Invalid modulename parameter');
1355     }
1356
1357     $outputarray = array();
1358
1359     if (empty($courses) || !is_array($courses) || count($courses) == 0) {
1360         return $outputarray;
1361     }
1362
1363     list($coursessql, $params) = $DB->get_in_or_equal(array_keys($courses), SQL_PARAMS_NAMED, 'c0');
1364     $params['modulename'] = $modulename;
1365
1366     if (!$rawmods = $DB->get_records_sql("SELECT cm.id AS coursemodule, m.*, cw.section, cm.visible AS visible,
1367                                                  cm.groupmode, cm.groupingid
1368                                             FROM {course_modules} cm, {course_sections} cw, {modules} md,
1369                                                  {".$modulename."} m
1370                                            WHERE cm.course $coursessql AND
1371                                                  cm.instance = m.id AND
1372                                                  cm.section = cw.id AND
1373                                                  md.name = :modulename AND
1374                                                  md.id = cm.module", $params)) {
1375         return $outputarray;
1376     }
1377
1378     foreach ($courses as $course) {
1379         $modinfo = get_fast_modinfo($course, $userid);
1380
1381         if (empty($modinfo->instances[$modulename])) {
1382             continue;
1383         }
1384
1385         foreach ($modinfo->instances[$modulename] as $cm) {
1386             if (!$includeinvisible and !$cm->uservisible) {
1387                 continue;
1388             }
1389             if (!isset($rawmods[$cm->id])) {
1390                 continue;
1391             }
1392             $instance = $rawmods[$cm->id];
1393             if (!empty($cm->extra)) {
1394                 $instance->extra = $cm->extra;
1395             }
1396             $outputarray[] = $instance;
1397         }
1398     }
1399
1400     return $outputarray;
1401 }
1402
1403 /**
1404  * Returns an array of all the active instances of a particular module in a given course,
1405  * sorted in the order they are defined.
1406  *
1407  * Returns an array of all the active instances of a particular
1408  * module in a given course, sorted in the order they are defined
1409  * in the course. Returns an empty array on any errors.
1410  *
1411  * The returned objects includle the columns cw.section, cm.visible,
1412  * cm.groupmode, and cm.groupingid, and are indexed by cm.id.
1413  *
1414  * Simply calls {@link all_instances_in_courses()} with a single provided course
1415  *
1416  * @param string $modulename The name of the module to get instances for
1417  * @param object $course The course obect.
1418  * @return array of module instance objects, including some extra fields from the course_modules
1419  *          and course_sections tables, or an empty array if an error occurred.
1420  * @param int $userid
1421  * @param int $includeinvisible
1422  */
1423 function get_all_instances_in_course($modulename, $course, $userid=NULL, $includeinvisible=false) {
1424     return get_all_instances_in_courses($modulename, array($course->id => $course), $userid, $includeinvisible);
1425 }
1426
1427
1428 /**
1429  * Determine whether a module instance is visible within a course
1430  *
1431  * Given a valid module object with info about the id and course,
1432  * and the module's type (eg "forum") returns whether the object
1433  * is visible or not according to the 'eye' icon only.
1434  *
1435  * NOTE: This does NOT take into account visibility to a particular user.
1436  * To get visibility access for a specific user, use get_fast_modinfo, get a
1437  * cm_info object from this, and check the ->uservisible property; or use
1438  * the \core_availability\info_module::is_user_visible() static function.
1439  *
1440  * @global object
1441
1442  * @param $moduletype Name of the module eg 'forum'
1443  * @param $module Object which is the instance of the module
1444  * @return bool Success
1445  */
1446 function instance_is_visible($moduletype, $module) {
1447     global $DB;
1448
1449     if (!empty($module->id)) {
1450         $params = array('courseid'=>$module->course, 'moduletype'=>$moduletype, 'moduleid'=>$module->id);
1451         if ($records = $DB->get_records_sql("SELECT cm.instance, cm.visible, cm.groupingid, cm.id, cm.course
1452                                                FROM {course_modules} cm, {modules} m
1453                                               WHERE cm.course = :courseid AND
1454                                                     cm.module = m.id AND
1455                                                     m.name = :moduletype AND
1456                                                     cm.instance = :moduleid", $params)) {
1457
1458             foreach ($records as $record) { // there should only be one - use the first one
1459                 return $record->visible;
1460             }
1461         }
1462     }
1463     return true;  // visible by default!
1464 }
1465
1466
1467 /// LOG FUNCTIONS /////////////////////////////////////////////////////
1468
1469 /**
1470  * Get instance of log manager.
1471  *
1472  * @param bool $forcereload
1473  * @return \core\log\manager
1474  */
1475 function get_log_manager($forcereload = false) {
1476     /** @var \core\log\manager $singleton */
1477     static $singleton = null;
1478
1479     if ($forcereload and isset($singleton)) {
1480         $singleton->dispose();
1481         $singleton = null;
1482     }
1483
1484     if (isset($singleton)) {
1485         return $singleton;
1486     }
1487
1488     $classname = '\tool_log\log\manager';
1489     if (defined('LOG_MANAGER_CLASS')) {
1490         $classname = LOG_MANAGER_CLASS;
1491     }
1492
1493     if (!class_exists($classname)) {
1494         if (!empty($classname)) {
1495             debugging("Cannot find log manager class '$classname'.", DEBUG_DEVELOPER);
1496         }
1497         $classname = '\core\log\dummy_manager';
1498     }
1499
1500     $singleton = new $classname();
1501     return $singleton;
1502 }
1503
1504 /**
1505  * Add an entry to the config log table.
1506  *
1507  * These are "action" focussed rather than web server hits,
1508  * and provide a way to easily reconstruct changes to Moodle configuration.
1509  *
1510  * @package core
1511  * @category log
1512  * @global moodle_database $DB
1513  * @global stdClass $USER
1514  * @param    string  $name     The name of the configuration change action
1515                                For example 'filter_active' when activating or deactivating a filter
1516  * @param    string  $oldvalue The config setting's previous value
1517  * @param    string  $value    The config setting's new value
1518  * @param    string  $plugin   Plugin name, for example a filter name when changing filter configuration
1519  * @return void
1520  */
1521 function add_to_config_log($name, $oldvalue, $value, $plugin) {
1522     global $USER, $DB;
1523
1524     $log = new stdClass();
1525     // Use 0 as user id during install.
1526     $log->userid       = during_initial_install() ? 0 : $USER->id;
1527     $log->timemodified = time();
1528     $log->name         = $name;
1529     $log->oldvalue  = $oldvalue;
1530     $log->value     = $value;
1531     $log->plugin    = $plugin;
1532
1533     $id = $DB->insert_record('config_log', $log);
1534
1535     $event = core\event\config_log_created::create(array(
1536             'objectid' => $id,
1537             'userid' => $log->userid,
1538             'context' => \context_system::instance(),
1539             'other' => array(
1540                 'name' => $log->name,
1541                 'oldvalue' => $log->oldvalue,
1542                 'value' => $log->value,
1543                 'plugin' => $log->plugin
1544             )
1545         ));
1546     $event->trigger();
1547 }
1548
1549 /**
1550  * Store user last access times - called when use enters a course or site
1551  *
1552  * @package core
1553  * @category log
1554  * @global stdClass $USER
1555  * @global stdClass $CFG
1556  * @global moodle_database $DB
1557  * @uses LASTACCESS_UPDATE_SECS
1558  * @uses SITEID
1559  * @param int $courseid  empty courseid means site
1560  * @return void
1561  */
1562 function user_accesstime_log($courseid=0) {
1563     global $USER, $CFG, $DB;
1564
1565     if (!isloggedin() or \core\session\manager::is_loggedinas()) {
1566         // no access tracking
1567         return;
1568     }
1569
1570     if (isguestuser()) {
1571         // Do not update guest access times/ips for performance.
1572         return;
1573     }
1574
1575     if (empty($courseid)) {
1576         $courseid = SITEID;
1577     }
1578
1579     $timenow = time();
1580
1581 /// Store site lastaccess time for the current user
1582     if ($timenow - $USER->lastaccess > LASTACCESS_UPDATE_SECS) {
1583     /// Update $USER->lastaccess for next checks
1584         $USER->lastaccess = $timenow;
1585
1586         $last = new stdClass();
1587         $last->id         = $USER->id;
1588         $last->lastip     = getremoteaddr();
1589         $last->lastaccess = $timenow;
1590
1591         $DB->update_record_raw('user', $last);
1592     }
1593
1594     if ($courseid == SITEID) {
1595     ///  no user_lastaccess for frontpage
1596         return;
1597     }
1598
1599 /// Store course lastaccess times for the current user
1600     if (empty($USER->currentcourseaccess[$courseid]) or ($timenow - $USER->currentcourseaccess[$courseid] > LASTACCESS_UPDATE_SECS)) {
1601
1602         $lastaccess = $DB->get_field('user_lastaccess', 'timeaccess', array('userid'=>$USER->id, 'courseid'=>$courseid));
1603
1604         if ($lastaccess === false) {
1605             // Update course lastaccess for next checks
1606             $USER->currentcourseaccess[$courseid] = $timenow;
1607
1608             $last = new stdClass();
1609             $last->userid     = $USER->id;
1610             $last->courseid   = $courseid;
1611             $last->timeaccess = $timenow;
1612             try {
1613                 $DB->insert_record_raw('user_lastaccess', $last, false);
1614             } catch (dml_write_exception $e) {
1615                 // During a race condition we can fail to find the data, then it appears.
1616                 // If we still can't find it, rethrow the exception.
1617                 $lastaccess = $DB->get_field('user_lastaccess', 'timeaccess', array('userid' => $USER->id,
1618                                                                                     'courseid' => $courseid));
1619                 if ($lastaccess === false) {
1620                     throw $e;
1621                 }
1622                 // If we did find it, the race condition was true and another thread has inserted the time for us.
1623                 // We can just continue without having to do anything.
1624             }
1625
1626         } else if ($timenow - $lastaccess <  LASTACCESS_UPDATE_SECS) {
1627             // no need to update now, it was updated recently in concurrent login ;-)
1628
1629         } else {
1630             // Update course lastaccess for next checks
1631             $USER->currentcourseaccess[$courseid] = $timenow;
1632
1633             $DB->set_field('user_lastaccess', 'timeaccess', $timenow, array('userid'=>$USER->id, 'courseid'=>$courseid));
1634         }
1635     }
1636 }
1637
1638 /// GENERAL HELPFUL THINGS  ///////////////////////////////////
1639
1640 /**
1641  * Dumps a given object's information for debugging purposes
1642  *
1643  * When used in a CLI script, the object's information is written to the standard
1644  * error output stream. When used in a web script, the object is dumped to a
1645  * pre-formatted block with the "notifytiny" CSS class.
1646  *
1647  * @param mixed $object The data to be printed
1648  * @return void output is echo'd
1649  */
1650 function print_object($object) {
1651
1652     // we may need a lot of memory here
1653     raise_memory_limit(MEMORY_EXTRA);
1654
1655     if (CLI_SCRIPT) {
1656         fwrite(STDERR, print_r($object, true));
1657         fwrite(STDERR, PHP_EOL);
1658     } else if (AJAX_SCRIPT) {
1659         foreach (explode("\n", print_r($object, true)) as $line) {
1660             error_log($line);
1661         }
1662     } else {
1663         echo html_writer::tag('pre', s(print_r($object, true)), array('class' => 'notifytiny'));
1664     }
1665 }
1666
1667 /**
1668  * This function is the official hook inside XMLDB stuff to delegate its debug to one
1669  * external function.
1670  *
1671  * Any script can avoid calls to this function by defining XMLDB_SKIP_DEBUG_HOOK before
1672  * using XMLDB classes. Obviously, also, if this function doesn't exist, it isn't invoked ;-)
1673  *
1674  * @uses DEBUG_DEVELOPER
1675  * @param string $message string contains the error message
1676  * @param object $object object XMLDB object that fired the debug
1677  */
1678 function xmldb_debug($message, $object) {
1679
1680     debugging($message, DEBUG_DEVELOPER);
1681 }
1682
1683 /**
1684  * @global object
1685  * @uses CONTEXT_COURSECAT
1686  * @return boolean Whether the user can create courses in any category in the system.
1687  */
1688 function user_can_create_courses() {
1689     global $DB;
1690     $catsrs = $DB->get_recordset('course_categories');
1691     foreach ($catsrs as $cat) {
1692         if (has_capability('moodle/course:create', context_coursecat::instance($cat->id))) {
1693             $catsrs->close();
1694             return true;
1695         }
1696     }
1697     $catsrs->close();
1698     return false;
1699 }
1700
1701 /**
1702  * This method can update the values in mulitple database rows for a colum with
1703  * a unique index, without violating that constraint.
1704  *
1705  * Suppose we have a table with a unique index on (otherid, sortorder), and
1706  * for a particular value of otherid, we want to change all the sort orders.
1707  * You have to do this carefully or you will violate the unique index at some time.
1708  * This method takes care of the details for you.
1709  *
1710  * Note that, it is the responsibility of the caller to make sure that the
1711  * requested rename is legal. For example, if you ask for [1 => 2, 2 => 2]
1712  * then you will get a unique key violation error from the database.
1713  *
1714  * @param string $table The database table to modify.
1715  * @param string $field the field that contains the values we are going to change.
1716  * @param array $newvalues oldvalue => newvalue how to change the values.
1717  *      E.g. [1 => 4, 2 => 1, 3 => 3, 4 => 2].
1718  * @param array $otherconditions array fieldname => requestedvalue extra WHERE clause
1719  *      conditions to restrict which rows are affected. E.g. array('otherid' => 123).
1720  * @param int $unusedvalue (defaults to -1) a value that is never used in $ordercol.
1721  */
1722 function update_field_with_unique_index($table, $field, array $newvalues,
1723         array $otherconditions, $unusedvalue = -1) {
1724     global $DB;
1725     $safechanges = decompose_update_into_safe_changes($newvalues, $unusedvalue);
1726
1727     $transaction = $DB->start_delegated_transaction();
1728     foreach ($safechanges as $change) {
1729         list($from, $to) = $change;
1730         $otherconditions[$field] = $from;
1731         $DB->set_field($table, $field, $to, $otherconditions);
1732     }
1733     $transaction->allow_commit();
1734 }
1735
1736 /**
1737  * Helper used by {@link update_field_with_unique_index()}. Given a desired
1738  * set of changes, break them down into single udpates that can be done one at
1739  * a time without breaking any unique index constraints.
1740  *
1741  * Suppose the input is array(1 => 2, 2 => 1) and -1. Then the output will be
1742  * array (array(1, -1), array(2, 1), array(-1, 2)). This function solves this
1743  * problem in the general case, not just for simple swaps. The unit tests give
1744  * more examples.
1745  *
1746  * Note that, it is the responsibility of the caller to make sure that the
1747  * requested rename is legal. For example, if you ask for something impossible
1748  * like array(1 => 2, 2 => 2) then the results are undefined. (You will probably
1749  * get a unique key violation error from the database later.)
1750  *
1751  * @param array $newvalues The desired re-ordering.
1752  *      E.g. array(1 => 4, 2 => 1, 3 => 3, 4 => 2).
1753  * @param int $unusedvalue A value that is not currently used.
1754  * @return array A safe way to perform the re-order. An array of two-element
1755  *      arrays array($from, $to).
1756  *      E.g. array(array(1, -1), array(2, 1), array(4, 2), array(-1, 4)).
1757  */
1758 function decompose_update_into_safe_changes(array $newvalues, $unusedvalue) {
1759     $nontrivialmap = array();
1760     foreach ($newvalues as $from => $to) {
1761         if ($from == $unusedvalue || $to == $unusedvalue) {
1762             throw new \coding_exception('Supposedly unused value ' . $unusedvalue . ' is actually used!');
1763         }
1764         if ($from != $to) {
1765             $nontrivialmap[$from] = $to;
1766         }
1767     }
1768
1769     if (empty($nontrivialmap)) {
1770         return array();
1771     }
1772
1773     // First we deal with all renames that are not part of cycles.
1774     // This bit is O(n^2) and it ought to be possible to do better,
1775     // but it does not seem worth the effort.
1776     $safechanges = array();
1777     $nontrivialmapchanged = true;
1778     while ($nontrivialmapchanged) {
1779         $nontrivialmapchanged = false;
1780
1781         foreach ($nontrivialmap as $from => $to) {
1782             if (array_key_exists($to, $nontrivialmap)) {
1783                 continue; // Cannot currenly do this rename.
1784             }
1785             // Is safe to do this rename now.
1786             $safechanges[] = array($from, $to);
1787             unset($nontrivialmap[$from]);
1788             $nontrivialmapchanged = true;
1789         }
1790     }
1791
1792     // Are we done?
1793     if (empty($nontrivialmap)) {
1794         return $safechanges;
1795     }
1796
1797     // Now what is left in $nontrivialmap must be a permutation,
1798     // which must be a combination of disjoint cycles. We need to break them.
1799     while (!empty($nontrivialmap)) {
1800         // Extract the first cycle.
1801         reset($nontrivialmap);
1802         $current = $cyclestart = key($nontrivialmap);
1803         $cycle = array();
1804         do {
1805             $cycle[] = $current;
1806             $next = $nontrivialmap[$current];
1807             unset($nontrivialmap[$current]);
1808             $current = $next;
1809         } while ($current != $cyclestart);
1810
1811         // Now convert it to a sequence of safe renames by using a temp.
1812         $safechanges[] = array($cyclestart, $unusedvalue);
1813         $cycle[0] = $unusedvalue;
1814         $to = $cyclestart;
1815         while ($from = array_pop($cycle)) {
1816             $safechanges[] = array($from, $to);
1817             $to = $from;
1818         }
1819     }
1820
1821     return $safechanges;
1822 }
1823
1824 /**
1825  * Return maximum number of courses in a category
1826  *
1827  * @uses MAX_COURSES_IN_CATEGORY
1828  * @return int number of courses
1829  */
1830 function get_max_courses_in_category() {
1831     global $CFG;
1832     // Use default MAX_COURSES_IN_CATEGORY if $CFG->maxcoursesincategory is not set or invalid.
1833     if (!isset($CFG->maxcoursesincategory) || clean_param($CFG->maxcoursesincategory, PARAM_INT) == 0) {
1834         return MAX_COURSES_IN_CATEGORY;
1835     } else {
1836         return $CFG->maxcoursesincategory;
1837     }
1838 }