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PHP Cross Reference of moodle-2.8 |
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1 <?php 2 // This file is part of Moodle - http://moodle.org/ 3 // 4 // Moodle is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // Moodle is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU General Public License for more details. 13 // 14 // You should have received a copy of the GNU General Public License 15 // along with Moodle. If not, see <http://www.gnu.org/licenses/>. 16 17 /** 18 * Library of functions for 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 if (!defined('LASTACCESS_UPDATE_SECS')) { 50 define('LASTACCESS_UPDATE_SECS', 60); 51 } 52 53 /** 54 * Returns $user object of the main admin user 55 * 56 * @static stdClass $mainadmin 57 * @return stdClass {@link $USER} record from DB, false if not found 58 */ 59 function get_admin() { 60 global $CFG, $DB; 61 62 static $mainadmin = null; 63 static $prevadmins = null; 64 65 if (empty($CFG->siteadmins)) { 66 // Should not happen on an ordinary site. 67 // It does however happen during unit tests. 68 return false; 69 } 70 71 if (isset($mainadmin) and $prevadmins === $CFG->siteadmins) { 72 return clone($mainadmin); 73 } 74 75 $mainadmin = null; 76 77 foreach (explode(',', $CFG->siteadmins) as $id) { 78 if ($user = $DB->get_record('user', array('id'=>$id, 'deleted'=>0))) { 79 $mainadmin = $user; 80 break; 81 } 82 } 83 84 if ($mainadmin) { 85 $prevadmins = $CFG->siteadmins; 86 return clone($mainadmin); 87 } else { 88 // this should not happen 89 return false; 90 } 91 } 92 93 /** 94 * Returns list of all admins, using 1 DB query 95 * 96 * @return array 97 */ 98 function get_admins() { 99 global $DB, $CFG; 100 101 if (empty($CFG->siteadmins)) { // Should not happen on an ordinary site 102 return array(); 103 } 104 105 $sql = "SELECT u.* 106 FROM {user} u 107 WHERE u.deleted = 0 AND u.id IN ($CFG->siteadmins)"; 108 109 // We want the same order as in $CFG->siteadmins. 110 $records = $DB->get_records_sql($sql); 111 $admins = array(); 112 foreach (explode(',', $CFG->siteadmins) as $id) { 113 $id = (int)$id; 114 if (!isset($records[$id])) { 115 // User does not exist, this should not happen. 116 continue; 117 } 118 $admins[$records[$id]->id] = $records[$id]; 119 } 120 121 return $admins; 122 } 123 124 /** 125 * Search through course users 126 * 127 * If $coursid specifies the site course then this function searches 128 * through all undeleted and confirmed users 129 * 130 * @global object 131 * @uses SITEID 132 * @uses SQL_PARAMS_NAMED 133 * @uses CONTEXT_COURSE 134 * @param int $courseid The course in question. 135 * @param int $groupid The group in question. 136 * @param string $searchtext The string to search for 137 * @param string $sort A field to sort by 138 * @param array $exceptions A list of IDs to ignore, eg 2,4,5,8,9,10 139 * @return array 140 */ 141 function search_users($courseid, $groupid, $searchtext, $sort='', array $exceptions=null) { 142 global $DB; 143 144 $fullname = $DB->sql_fullname('u.firstname', 'u.lastname'); 145 146 if (!empty($exceptions)) { 147 list($exceptions, $params) = $DB->get_in_or_equal($exceptions, SQL_PARAMS_NAMED, 'ex', false); 148 $except = "AND u.id $exceptions"; 149 } else { 150 $except = ""; 151 $params = array(); 152 } 153 154 if (!empty($sort)) { 155 $order = "ORDER BY $sort"; 156 } else { 157 $order = ""; 158 } 159 160 $select = "u.deleted = 0 AND u.confirmed = 1 AND (".$DB->sql_like($fullname, ':search1', false)." OR ".$DB->sql_like('u.email', ':search2', false).")"; 161 $params['search1'] = "%$searchtext%"; 162 $params['search2'] = "%$searchtext%"; 163 164 if (!$courseid or $courseid == SITEID) { 165 $sql = "SELECT u.id, u.firstname, u.lastname, u.email 166 FROM {user} u 167 WHERE $select 168 $except 169 $order"; 170 return $DB->get_records_sql($sql, $params); 171 172 } else { 173 if ($groupid) { 174 $sql = "SELECT u.id, u.firstname, u.lastname, u.email 175 FROM {user} u 176 JOIN {groups_members} gm ON gm.userid = u.id 177 WHERE $select AND gm.groupid = :groupid 178 $except 179 $order"; 180 $params['groupid'] = $groupid; 181 return $DB->get_records_sql($sql, $params); 182 183 } else { 184 $context = context_course::instance($courseid); 185 186 // We want to query both the current context and parent contexts. 187 list($relatedctxsql, $relatedctxparams) = $DB->get_in_or_equal($context->get_parent_context_ids(true), SQL_PARAMS_NAMED, 'relatedctx'); 188 189 $sql = "SELECT u.id, u.firstname, u.lastname, u.email 190 FROM {user} u 191 JOIN {role_assignments} ra ON ra.userid = u.id 192 WHERE $select AND ra.contextid $relatedctxsql 193 $except 194 $order"; 195 $params = array_merge($params, $relatedctxparams); 196 return $DB->get_records_sql($sql, $params); 197 } 198 } 199 } 200 201 /** 202 * Returns SQL used to search through user table to find users (in a query 203 * which may also join and apply other conditions). 204 * 205 * You can combine this SQL with an existing query by adding 'AND $sql' to the 206 * WHERE clause of your query (where $sql is the first element in the array 207 * returned by this function), and merging in the $params array to the parameters 208 * of your query (where $params is the second element). Your query should use 209 * named parameters such as :param, rather than the question mark style. 210 * 211 * There are examples of basic usage in the unit test for this function. 212 * 213 * @param string $search the text to search for (empty string = find all) 214 * @param string $u the table alias for the user table in the query being 215 * built. May be ''. 216 * @param bool $searchanywhere If true (default), searches in the middle of 217 * names, otherwise only searches at start 218 * @param array $extrafields Array of extra user fields to include in search 219 * @param array $exclude Array of user ids to exclude (empty = don't exclude) 220 * @param array $includeonly If specified, only returns users that have ids 221 * incldued in this array (empty = don't restrict) 222 * @return array an array with two elements, a fragment of SQL to go in the 223 * where clause the query, and an associative array containing any required 224 * parameters (using named placeholders). 225 */ 226 function users_search_sql($search, $u = 'u', $searchanywhere = true, array $extrafields = array(), 227 array $exclude = null, array $includeonly = null) { 228 global $DB, $CFG; 229 $params = array(); 230 $tests = array(); 231 232 if ($u) { 233 $u .= '.'; 234 } 235 236 // If we have a $search string, put a field LIKE '$search%' condition on each field. 237 if ($search) { 238 $conditions = array( 239 $DB->sql_fullname($u . 'firstname', $u . 'lastname'), 240 $conditions[] = $u . 'lastname' 241 ); 242 foreach ($extrafields as $field) { 243 $conditions[] = $u . $field; 244 } 245 if ($searchanywhere) { 246 $searchparam = '%' . $search . '%'; 247 } else { 248 $searchparam = $search . '%'; 249 } 250 $i = 0; 251 foreach ($conditions as $key => $condition) { 252 $conditions[$key] = $DB->sql_like($condition, ":con{$i}00", false, false); 253 $params["con{$i}00"] = $searchparam; 254 $i++; 255 } 256 $tests[] = '(' . implode(' OR ', $conditions) . ')'; 257 } 258 259 // Add some additional sensible conditions. 260 $tests[] = $u . "id <> :guestid"; 261 $params['guestid'] = $CFG->siteguest; 262 $tests[] = $u . 'deleted = 0'; 263 $tests[] = $u . 'confirmed = 1'; 264 265 // If we are being asked to exclude any users, do that. 266 if (!empty($exclude)) { 267 list($usertest, $userparams) = $DB->get_in_or_equal($exclude, SQL_PARAMS_NAMED, 'ex', false); 268 $tests[] = $u . 'id ' . $usertest; 269 $params = array_merge($params, $userparams); 270 } 271 272 // If we are validating a set list of userids, add an id IN (...) test. 273 if (!empty($includeonly)) { 274 list($usertest, $userparams) = $DB->get_in_or_equal($includeonly, SQL_PARAMS_NAMED, 'val'); 275 $tests[] = $u . 'id ' . $usertest; 276 $params = array_merge($params, $userparams); 277 } 278 279 // In case there are no tests, add one result (this makes it easier to combine 280 // this with an existing query as you can always add AND $sql). 281 if (empty($tests)) { 282 $tests[] = '1 = 1'; 283 } 284 285 // Combing the conditions and return. 286 return array(implode(' AND ', $tests), $params); 287 } 288 289 290 /** 291 * This function generates the standard ORDER BY clause for use when generating 292 * lists of users. If you don't have a reason to use a different order, then 293 * you should use this method to generate the order when displaying lists of users. 294 * 295 * If the optional $search parameter is passed, then exact matches to the search 296 * will be sorted first. For example, suppose you have two users 'Al Zebra' and 297 * 'Alan Aardvark'. The default sort is Alan, then Al. If, however, you search for 298 * 'Al', then Al will be listed first. (With two users, this is not a big deal, 299 * but with thousands of users, it is essential.) 300 * 301 * The list of fields scanned for exact matches are: 302 * - firstname 303 * - lastname 304 * - $DB->sql_fullname 305 * - those returned by get_extra_user_fields 306 * 307 * If named parameters are used (which is the default, and highly recommended), 308 * then the parameter names are like :usersortexactN, where N is an int. 309 * 310 * The simplest possible example use is: 311 * list($sort, $params) = users_order_by_sql(); 312 * $sql = 'SELECT * FROM {users} ORDER BY ' . $sort; 313 * 314 * A more complex example, showing that this sort can be combined with other sorts: 315 * list($sort, $sortparams) = users_order_by_sql('u'); 316 * $sql = "SELECT g.id AS groupid, gg.groupingid, u.id AS userid, u.firstname, u.lastname, u.idnumber, u.username 317 * FROM {groups} g 318 * LEFT JOIN {groupings_groups} gg ON g.id = gg.groupid 319 * LEFT JOIN {groups_members} gm ON g.id = gm.groupid 320 * LEFT JOIN {user} u ON gm.userid = u.id 321 * WHERE g.courseid = :courseid $groupwhere $groupingwhere 322 * ORDER BY g.name, $sort"; 323 * $params += $sortparams; 324 * 325 * An example showing the use of $search: 326 * list($sort, $sortparams) = users_order_by_sql('u', $search, $this->get_context()); 327 * $order = ' ORDER BY ' . $sort; 328 * $params += $sortparams; 329 * $availableusers = $DB->get_records_sql($fields . $sql . $order, $params, $page*$perpage, $perpage); 330 * 331 * @param string $usertablealias (optional) any table prefix for the {users} table. E.g. 'u'. 332 * @param string $search (optional) a current search string. If given, 333 * any exact matches to this string will be sorted first. 334 * @param context $context the context we are in. Use by get_extra_user_fields. 335 * Defaults to $PAGE->context. 336 * @return array with two elements: 337 * string SQL fragment to use in the ORDER BY clause. For example, "firstname, lastname". 338 * array of parameters used in the SQL fragment. 339 */ 340 function users_order_by_sql($usertablealias = '', $search = null, context $context = null) { 341 global $DB, $PAGE; 342 343 if ($usertablealias) { 344 $tableprefix = $usertablealias . '.'; 345 } else { 346 $tableprefix = ''; 347 } 348 349 $sort = "{$tableprefix}lastname, {$tableprefix}firstname, {$tableprefix}id"; 350 $params = array(); 351 352 if (!$search) { 353 return array($sort, $params); 354 } 355 356 if (!$context) { 357 $context = $PAGE->context; 358 } 359 360 $exactconditions = array(); 361 $paramkey = 'usersortexact1'; 362 363 $exactconditions[] = $DB->sql_fullname($tableprefix . 'firstname', $tableprefix . 'lastname') . 364 ' = :' . $paramkey; 365 $params[$paramkey] = $search; 366 $paramkey++; 367 368 $fieldstocheck = array_merge(array('firstname', 'lastname'), get_extra_user_fields($context)); 369 foreach ($fieldstocheck as $key => $field) { 370 $exactconditions[] = 'LOWER(' . $tableprefix . $field . ') = LOWER(:' . $paramkey . ')'; 371 $params[$paramkey] = $search; 372 $paramkey++; 373 } 374 375 $sort = 'CASE WHEN ' . implode(' OR ', $exactconditions) . 376 ' THEN 0 ELSE 1 END, ' . $sort; 377 378 return array($sort, $params); 379 } 380 381 /** 382 * Returns a subset of users 383 * 384 * @global object 385 * @uses DEBUG_DEVELOPER 386 * @uses SQL_PARAMS_NAMED 387 * @param bool $get If false then only a count of the records is returned 388 * @param string $search A simple string to search for 389 * @param bool $confirmed A switch to allow/disallow unconfirmed users 390 * @param array $exceptions A list of IDs to ignore, eg 2,4,5,8,9,10 391 * @param string $sort A SQL snippet for the sorting criteria to use 392 * @param string $firstinitial Users whose first name starts with $firstinitial 393 * @param string $lastinitial Users whose last name starts with $lastinitial 394 * @param string $page The page or records to return 395 * @param string $recordsperpage The number of records to return per page 396 * @param string $fields A comma separated list of fields to be returned from the chosen table. 397 * @return array|int|bool {@link $USER} records unless get is false in which case the integer count of the records found is returned. 398 * False is returned if an error is encountered. 399 */ 400 function get_users($get=true, $search='', $confirmed=false, array $exceptions=null, $sort='firstname ASC', 401 $firstinitial='', $lastinitial='', $page='', $recordsperpage='', $fields='*', $extraselect='', array $extraparams=null) { 402 global $DB, $CFG; 403 404 if ($get && !$recordsperpage) { 405 debugging('Call to get_users with $get = true no $recordsperpage limit. ' . 406 'On large installations, this will probably cause an out of memory error. ' . 407 'Please think again and change your code so that it does not try to ' . 408 'load so much data into memory.', DEBUG_DEVELOPER); 409 } 410 411 $fullname = $DB->sql_fullname(); 412 413 $select = " id <> :guestid AND deleted = 0"; 414 $params = array('guestid'=>$CFG->siteguest); 415 416 if (!empty($search)){ 417 $search = trim($search); 418 $select .= " AND (".$DB->sql_like($fullname, ':search1', false)." OR ".$DB->sql_like('email', ':search2', false)." OR username = :search3)"; 419 $params['search1'] = "%$search%"; 420 $params['search2'] = "%$search%"; 421 $params['search3'] = "$search"; 422 } 423 424 if ($confirmed) { 425 $select .= " AND confirmed = 1"; 426 } 427 428 if ($exceptions) { 429 list($exceptions, $eparams) = $DB->get_in_or_equal($exceptions, SQL_PARAMS_NAMED, 'ex', false); 430 $params = $params + $eparams; 431 $select .= " AND id $exceptions"; 432 } 433 434 if ($firstinitial) { 435 $select .= " AND ".$DB->sql_like('firstname', ':fni', false, false); 436 $params['fni'] = "$firstinitial%"; 437 } 438 if ($lastinitial) { 439 $select .= " AND ".$DB->sql_like('lastname', ':lni', false, false); 440 $params['lni'] = "$lastinitial%"; 441 } 442 443 if ($extraselect) { 444 $select .= " AND $extraselect"; 445 $params = $params + (array)$extraparams; 446 } 447 448 if ($get) { 449 return $DB->get_records_select('user', $select, $params, $sort, $fields, $page, $recordsperpage); 450 } else { 451 return $DB->count_records_select('user', $select, $params); 452 } 453 } 454 455 456 /** 457 * Return filtered (if provided) list of users in site, except guest and deleted users. 458 * 459 * @param string $sort An SQL field to sort by 460 * @param string $dir The sort direction ASC|DESC 461 * @param int $page The page or records to return 462 * @param int $recordsperpage The number of records to return per page 463 * @param string $search A simple string to search for 464 * @param string $firstinitial Users whose first name starts with $firstinitial 465 * @param string $lastinitial Users whose last name starts with $lastinitial 466 * @param string $extraselect An additional SQL select statement to append to the query 467 * @param array $extraparams Additional parameters to use for the above $extraselect 468 * @param stdClass $extracontext If specified, will include user 'extra fields' 469 * as appropriate for current user and given context 470 * @return array Array of {@link $USER} records 471 */ 472 function get_users_listing($sort='lastaccess', $dir='ASC', $page=0, $recordsperpage=0, 473 $search='', $firstinitial='', $lastinitial='', $extraselect='', 474 array $extraparams=null, $extracontext = null) { 475 global $DB, $CFG; 476 477 $fullname = $DB->sql_fullname(); 478 479 $select = "deleted <> 1 AND id <> :guestid"; 480 $params = array('guestid' => $CFG->siteguest); 481 482 if (!empty($search)) { 483 $search = trim($search); 484 $select .= " AND (". $DB->sql_like($fullname, ':search1', false, false). 485 " OR ". $DB->sql_like('email', ':search2', false, false). 486 " OR username = :search3)"; 487 $params['search1'] = "%$search%"; 488 $params['search2'] = "%$search%"; 489 $params['search3'] = "$search"; 490 } 491 492 if ($firstinitial) { 493 $select .= " AND ". $DB->sql_like('firstname', ':fni', false, false); 494 $params['fni'] = "$firstinitial%"; 495 } 496 if ($lastinitial) { 497 $select .= " AND ". $DB->sql_like('lastname', ':lni', false, false); 498 $params['lni'] = "$lastinitial%"; 499 } 500 501 if ($extraselect) { 502 $select .= " AND $extraselect"; 503 $params = $params + (array)$extraparams; 504 } 505 506 if ($sort) { 507 $sort = " ORDER BY $sort $dir"; 508 } 509 510 // If a context is specified, get extra user fields that the current user 511 // is supposed to see. 512 $extrafields = ''; 513 if ($extracontext) { 514 $extrafields = get_extra_user_fields_sql($extracontext, '', '', 515 array('id', 'username', 'email', 'firstname', 'lastname', 'city', 'country', 516 'lastaccess', 'confirmed', 'mnethostid')); 517 } 518 $namefields = get_all_user_name_fields(true); 519 $extrafields = "$extrafields, $namefields"; 520 521 // warning: will return UNCONFIRMED USERS 522 return $DB->get_records_sql("SELECT id, username, email, city, country, lastaccess, confirmed, mnethostid, suspended $extrafields 523 FROM {user} 524 WHERE $select 525 $sort", $params, $page, $recordsperpage); 526 527 } 528 529 530 /** 531 * Full list of users that have confirmed their accounts. 532 * 533 * @global object 534 * @return array of unconfirmed users 535 */ 536 function get_users_confirmed() { 537 global $DB, $CFG; 538 return $DB->get_records_sql("SELECT * 539 FROM {user} 540 WHERE confirmed = 1 AND deleted = 0 AND id <> ?", array($CFG->siteguest)); 541 } 542 543 544 /// OTHER SITE AND COURSE FUNCTIONS ///////////////////////////////////////////// 545 546 547 /** 548 * Returns $course object of the top-level site. 549 * 550 * @return object A {@link $COURSE} object for the site, exception if not found 551 */ 552 function get_site() { 553 global $SITE, $DB; 554 555 if (!empty($SITE->id)) { // We already have a global to use, so return that 556 return $SITE; 557 } 558 559 if ($course = $DB->get_record('course', array('category'=>0))) { 560 return $course; 561 } else { 562 // course table exists, but the site is not there, 563 // unfortunately there is no automatic way to recover 564 throw new moodle_exception('nosite', 'error'); 565 } 566 } 567 568 /** 569 * Gets a course object from database. If the course id corresponds to an 570 * already-loaded $COURSE or $SITE object, then the loaded object will be used, 571 * saving a database query. 572 * 573 * If it reuses an existing object, by default the object will be cloned. This 574 * means you can modify the object safely without affecting other code. 575 * 576 * @param int $courseid Course id 577 * @param bool $clone If true (default), makes a clone of the record 578 * @return stdClass A course object 579 * @throws dml_exception If not found in database 580 */ 581 function get_course($courseid, $clone = true) { 582 global $DB, $COURSE, $SITE; 583 if (!empty($COURSE->id) && $COURSE->id == $courseid) { 584 return $clone ? clone($COURSE) : $COURSE; 585 } else if (!empty($SITE->id) && $SITE->id == $courseid) { 586 return $clone ? clone($SITE) : $SITE; 587 } else { 588 return $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST); 589 } 590 } 591 592 /** 593 * Returns list of courses, for whole site, or category 594 * 595 * Returns list of courses, for whole site, or category 596 * Important: Using c.* for fields is extremely expensive because 597 * we are using distinct. You almost _NEVER_ need all the fields 598 * in such a large SELECT 599 * 600 * @global object 601 * @global object 602 * @global object 603 * @uses CONTEXT_COURSE 604 * @param string|int $categoryid Either a category id or 'all' for everything 605 * @param string $sort A field and direction to sort by 606 * @param string $fields The additional fields to return 607 * @return array Array of courses 608 */ 609 function get_courses($categoryid="all", $sort="c.sortorder ASC", $fields="c.*") { 610 611 global $USER, $CFG, $DB; 612 613 $params = array(); 614 615 if ($categoryid !== "all" && is_numeric($categoryid)) { 616 $categoryselect = "WHERE c.category = :catid"; 617 $params['catid'] = $categoryid; 618 } else { 619 $categoryselect = ""; 620 } 621 622 if (empty($sort)) { 623 $sortstatement = ""; 624 } else { 625 $sortstatement = "ORDER BY $sort"; 626 } 627 628 $visiblecourses = array(); 629 630 $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx'); 631 $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)"; 632 $params['contextlevel'] = CONTEXT_COURSE; 633 634 $sql = "SELECT $fields $ccselect 635 FROM {course} c 636 $ccjoin 637 $categoryselect 638 $sortstatement"; 639 640 // pull out all course matching the cat 641 if ($courses = $DB->get_records_sql($sql, $params)) { 642 643 // loop throught them 644 foreach ($courses as $course) { 645 context_helper::preload_from_record($course); 646 if (isset($course->visible) && $course->visible <= 0) { 647 // for hidden courses, require visibility check 648 if (has_capability('moodle/course:viewhiddencourses', context_course::instance($course->id))) { 649 $visiblecourses [$course->id] = $course; 650 } 651 } else { 652 $visiblecourses [$course->id] = $course; 653 } 654 } 655 } 656 return $visiblecourses; 657 } 658 659 660 /** 661 * Returns list of courses, for whole site, or category 662 * 663 * Similar to get_courses, but allows paging 664 * Important: Using c.* for fields is extremely expensive because 665 * we are using distinct. You almost _NEVER_ need all the fields 666 * in such a large SELECT 667 * 668 * @global object 669 * @global object 670 * @global object 671 * @uses CONTEXT_COURSE 672 * @param string|int $categoryid Either a category id or 'all' for everything 673 * @param string $sort A field and direction to sort by 674 * @param string $fields The additional fields to return 675 * @param int $totalcount Reference for the number of courses 676 * @param string $limitfrom The course to start from 677 * @param string $limitnum The number of courses to limit to 678 * @return array Array of courses 679 */ 680 function get_courses_page($categoryid="all", $sort="c.sortorder ASC", $fields="c.*", 681 &$totalcount, $limitfrom="", $limitnum="") { 682 global $USER, $CFG, $DB; 683 684 $params = array(); 685 686 $categoryselect = ""; 687 if ($categoryid !== "all" && is_numeric($categoryid)) { 688 $categoryselect = "WHERE c.category = :catid"; 689 $params['catid'] = $categoryid; 690 } else { 691 $categoryselect = ""; 692 } 693 694 $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx'); 695 $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)"; 696 $params['contextlevel'] = CONTEXT_COURSE; 697 698 $totalcount = 0; 699 if (!$limitfrom) { 700 $limitfrom = 0; 701 } 702 $visiblecourses = array(); 703 704 $sql = "SELECT $fields $ccselect 705 FROM {course} c 706 $ccjoin 707 $categoryselect 708 ORDER BY $sort"; 709 710 // pull out all course matching the cat 711 $rs = $DB->get_recordset_sql($sql, $params); 712 // iteration will have to be done inside loop to keep track of the limitfrom and limitnum 713 foreach($rs as $course) { 714 context_helper::preload_from_record($course); 715 if ($course->visible <= 0) { 716 // for hidden courses, require visibility check 717 if (has_capability('moodle/course:viewhiddencourses', context_course::instance($course->id))) { 718 $totalcount++; 719 if ($totalcount > $limitfrom && (!$limitnum or count($visiblecourses) < $limitnum)) { 720 $visiblecourses [$course->id] = $course; 721 } 722 } 723 } else { 724 $totalcount++; 725 if ($totalcount > $limitfrom && (!$limitnum or count($visiblecourses) < $limitnum)) { 726 $visiblecourses [$course->id] = $course; 727 } 728 } 729 } 730 $rs->close(); 731 return $visiblecourses; 732 } 733 734 /** 735 * A list of courses that match a search 736 * 737 * @global object 738 * @global object 739 * @param array $searchterms An array of search criteria 740 * @param string $sort A field and direction to sort by 741 * @param int $page The page number to get 742 * @param int $recordsperpage The number of records per page 743 * @param int $totalcount Passed in by reference. 744 * @return object {@link $COURSE} records 745 */ 746 function get_courses_search($searchterms, $sort, $page, $recordsperpage, &$totalcount) { 747 global $CFG, $DB; 748 749 if ($DB->sql_regex_supported()) { 750 $REGEXP = $DB->sql_regex(true); 751 $NOTREGEXP = $DB->sql_regex(false); 752 } 753 754 $searchcond = array(); 755 $params = array(); 756 $i = 0; 757 758 // Thanks Oracle for your non-ansi concat and type limits in coalesce. MDL-29912 759 if ($DB->get_dbfamily() == 'oracle') { 760 $concat = "(c.summary|| ' ' || c.fullname || ' ' || c.idnumber || ' ' || c.shortname)"; 761 } else { 762 $concat = $DB->sql_concat("COALESCE(c.summary, '')", "' '", 'c.fullname', "' '", 'c.idnumber', "' '", 'c.shortname'); 763 } 764 765 foreach ($searchterms as $searchterm) { 766 $i++; 767 768 $NOT = false; /// Initially we aren't going to perform NOT LIKE searches, only MSSQL and Oracle 769 /// will use it to simulate the "-" operator with LIKE clause 770 771 /// Under Oracle and MSSQL, trim the + and - operators and perform 772 /// simpler LIKE (or NOT LIKE) queries 773 if (!$DB->sql_regex_supported()) { 774 if (substr($searchterm, 0, 1) == '-') { 775 $NOT = true; 776 } 777 $searchterm = trim($searchterm, '+-'); 778 } 779 780 // TODO: +- may not work for non latin languages 781 782 if (substr($searchterm,0,1) == '+') { 783 $searchterm = trim($searchterm, '+-'); 784 $searchterm = preg_quote($searchterm, '|'); 785 $searchcond[] = "$concat $REGEXP :ss$i"; 786 $params['ss'.$i] = "(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)"; 787 788 } else if (substr($searchterm,0,1) == "-") { 789 $searchterm = trim($searchterm, '+-'); 790 $searchterm = preg_quote($searchterm, '|'); 791 $searchcond[] = "$concat $NOTREGEXP :ss$i"; 792 $params['ss'.$i] = "(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)"; 793 794 } else { 795 $searchcond[] = $DB->sql_like($concat,":ss$i", false, true, $NOT); 796 $params['ss'.$i] = "%$searchterm%"; 797 } 798 } 799 800 if (empty($searchcond)) { 801 $totalcount = 0; 802 return array(); 803 } 804 805 $searchcond = implode(" AND ", $searchcond); 806 807 $courses = array(); 808 $c = 0; // counts how many visible courses we've seen 809 810 // Tiki pagination 811 $limitfrom = $page * $recordsperpage; 812 $limitto = $limitfrom + $recordsperpage; 813 814 $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx'); 815 $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)"; 816 $params['contextlevel'] = CONTEXT_COURSE; 817 818 $sql = "SELECT c.* $ccselect 819 FROM {course} c 820 $ccjoin 821 WHERE $searchcond AND c.id <> ".SITEID." 822 ORDER BY $sort"; 823 824 $rs = $DB->get_recordset_sql($sql, $params); 825 foreach($rs as $course) { 826 if (!$course->visible) { 827 // preload contexts only for hidden courses or courses we need to return 828 context_helper::preload_from_record($course); 829 $coursecontext = context_course::instance($course->id); 830 if (!has_capability('moodle/course:viewhiddencourses', $coursecontext)) { 831 continue; 832 } 833 } 834 // Don't exit this loop till the end 835 // we need to count all the visible courses 836 // to update $totalcount 837 if ($c >= $limitfrom && $c < $limitto) { 838 $courses[$course->id] = $course; 839 } 840 $c++; 841 } 842 $rs->close(); 843 844 // our caller expects 2 bits of data - our return 845 // array, and an updated $totalcount 846 $totalcount = $c; 847 return $courses; 848 } 849 850 /** 851 * Fixes course category and course sortorder, also verifies category and course parents and paths. 852 * (circular references are not fixed) 853 * 854 * @global object 855 * @global object 856 * @uses MAX_COURSES_IN_CATEGORY 857 * @uses MAX_COURSE_CATEGORIES 858 * @uses SITEID 859 * @uses CONTEXT_COURSE 860 * @return void 861 */ 862 function fix_course_sortorder() { 863 global $DB, $SITE; 864 865 //WARNING: this is PHP5 only code! 866 867 // if there are any changes made to courses or categories we will trigger 868 // the cache events to purge all cached courses/categories data 869 $cacheevents = array(); 870 871 if ($unsorted = $DB->get_records('course_categories', array('sortorder'=>0))) { 872 //move all categories that are not sorted yet to the end 873 $DB->set_field('course_categories', 'sortorder', MAX_COURSES_IN_CATEGORY*MAX_COURSE_CATEGORIES, array('sortorder'=>0)); 874 $cacheevents['changesincoursecat'] = true; 875 } 876 877 $allcats = $DB->get_records('course_categories', null, 'sortorder, id', 'id, sortorder, parent, depth, path'); 878 $topcats = array(); 879 $brokencats = array(); 880 foreach ($allcats as $cat) { 881 $sortorder = (int)$cat->sortorder; 882 if (!$cat->parent) { 883 while(isset($topcats[$sortorder])) { 884 $sortorder++; 885 } 886 $topcats[$sortorder] = $cat; 887 continue; 888 } 889 if (!isset($allcats[$cat->parent])) { 890 $brokencats[] = $cat; 891 continue; 892 } 893 if (!isset($allcats[$cat->parent]->children)) { 894 $allcats[$cat->parent]->children = array(); 895 } 896 while(isset($allcats[$cat->parent]->children[$sortorder])) { 897 $sortorder++; 898 } 899 $allcats[$cat->parent]->children[$sortorder] = $cat; 900 } 901 unset($allcats); 902 903 // add broken cats to category tree 904 if ($brokencats) { 905 $defaultcat = reset($topcats); 906 foreach ($brokencats as $cat) { 907 $topcats[] = $cat; 908 } 909 } 910 911 // now walk recursively the tree and fix any problems found 912 $sortorder = 0; 913 $fixcontexts = array(); 914 if (_fix_course_cats($topcats, $sortorder, 0, 0, '', $fixcontexts)) { 915 $cacheevents['changesincoursecat'] = true; 916 } 917 918 // detect if there are "multiple" frontpage courses and fix them if needed 919 $frontcourses = $DB->get_records('course', array('category'=>0), 'id'); 920 if (count($frontcourses) > 1) { 921 if (isset($frontcourses[SITEID])) { 922 $frontcourse = $frontcourses[SITEID]; 923 unset($frontcourses[SITEID]); 924 } else { 925 $frontcourse = array_shift($frontcourses); 926 } 927 $defaultcat = reset($topcats); 928 foreach ($frontcourses as $course) { 929 $DB->set_field('course', 'category', $defaultcat->id, array('id'=>$course->id)); 930 $context = context_course::instance($course->id); 931 $fixcontexts[$context->id] = $context; 932 $cacheevents['changesincourse'] = true; 933 } 934 unset($frontcourses); 935 } else { 936 $frontcourse = reset($frontcourses); 937 } 938 939 // now fix the paths and depths in context table if needed 940 if ($fixcontexts) { 941 foreach ($fixcontexts as $fixcontext) { 942 $fixcontext->reset_paths(false); 943 } 944 context_helper::build_all_paths(false); 945 unset($fixcontexts); 946 $cacheevents['changesincourse'] = true; 947 $cacheevents['changesincoursecat'] = true; 948 } 949 950 // release memory 951 unset($topcats); 952 unset($brokencats); 953 unset($fixcontexts); 954 955 // fix frontpage course sortorder 956 if ($frontcourse->sortorder != 1) { 957 $DB->set_field('course', 'sortorder', 1, array('id'=>$frontcourse->id)); 958 $cacheevents['changesincourse'] = true; 959 } 960 961 // now fix the course counts in category records if needed 962 $sql = "SELECT cc.id, cc.coursecount, COUNT(c.id) AS newcount 963 FROM {course_categories} cc 964 LEFT JOIN {course} c ON c.category = cc.id 965 GROUP BY cc.id, cc.coursecount 966 HAVING cc.coursecount <> COUNT(c.id)"; 967 968 if ($updatecounts = $DB->get_records_sql($sql)) { 969 // categories with more courses than MAX_COURSES_IN_CATEGORY 970 $categories = array(); 971 foreach ($updatecounts as $cat) { 972 $cat->coursecount = $cat->newcount; 973 if ($cat->coursecount >= MAX_COURSES_IN_CATEGORY) { 974 $categories[] = $cat->id; 975 } 976 unset($cat->newcount); 977 $DB->update_record_raw('course_categories', $cat, true); 978 } 979 if (!empty($categories)) { 980 $str = implode(', ', $categories); 981 debugging("The number of courses (category id: $str) has reached MAX_COURSES_IN_CATEGORY (" . MAX_COURSES_IN_CATEGORY . "), it will cause a sorting performance issue, please increase the value of MAX_COURSES_IN_CATEGORY in lib/datalib.php file. See tracker issue: MDL-25669", DEBUG_DEVELOPER); 982 } 983 $cacheevents['changesincoursecat'] = true; 984 } 985 986 // now make sure that sortorders in course table are withing the category sortorder ranges 987 $sql = "SELECT DISTINCT cc.id, cc.sortorder 988 FROM {course_categories} cc 989 JOIN {course} c ON c.category = cc.id 990 WHERE c.sortorder < cc.sortorder OR c.sortorder > cc.sortorder + ".MAX_COURSES_IN_CATEGORY; 991 992 if ($fixcategories = $DB->get_records_sql($sql)) { 993 //fix the course sortorder ranges 994 foreach ($fixcategories as $cat) { 995 $sql = "UPDATE {course} 996 SET sortorder = ".$DB->sql_modulo('sortorder', MAX_COURSES_IN_CATEGORY)." + ? 997 WHERE category = ?"; 998 $DB->execute($sql, array($cat->sortorder, $cat->id)); 999 } 1000 $cacheevents['changesincoursecat'] = true; 1001 } 1002 unset($fixcategories); 1003 1004 // categories having courses with sortorder duplicates or having gaps in sortorder 1005 $sql = "SELECT DISTINCT c1.category AS id , cc.sortorder 1006 FROM {course} c1 1007 JOIN {course} c2 ON c1.sortorder = c2.sortorder 1008 JOIN {course_categories} cc ON (c1.category = cc.id) 1009 WHERE c1.id <> c2.id"; 1010 $fixcategories = $DB->get_records_sql($sql); 1011 1012 $sql = "SELECT cc.id, cc.sortorder, cc.coursecount, MAX(c.sortorder) AS maxsort, MIN(c.sortorder) AS minsort 1013 FROM {course_categories} cc 1014 JOIN {course} c ON c.category = cc.id 1015 GROUP BY cc.id, cc.sortorder, cc.coursecount 1016 HAVING (MAX(c.sortorder) <> cc.sortorder + cc.coursecount) OR (MIN(c.sortorder) <> cc.sortorder + 1)"; 1017 $gapcategories = $DB->get_records_sql($sql); 1018 1019 foreach ($gapcategories as $cat) { 1020 if (isset($fixcategories[$cat->id])) { 1021 // duplicates detected already 1022 1023 } else if ($cat->minsort == $cat->sortorder and $cat->maxsort == $cat->sortorder + $cat->coursecount - 1) { 1024 // easy - new course inserted with sortorder 0, the rest is ok 1025 $sql = "UPDATE {course} 1026 SET sortorder = sortorder + 1 1027 WHERE category = ?"; 1028 $DB->execute($sql, array($cat->id)); 1029 1030 } else { 1031 // it needs full resorting 1032 $fixcategories[$cat->id] = $cat; 1033 } 1034 $cacheevents['changesincourse'] = true; 1035 } 1036 unset($gapcategories); 1037 1038 // fix course sortorders in problematic categories only 1039 foreach ($fixcategories as $cat) { 1040 $i = 1; 1041 $courses = $DB->get_records('course', array('category'=>$cat->id), 'sortorder ASC, id DESC', 'id, sortorder'); 1042 foreach ($courses as $course) { 1043 if ($course->sortorder != $cat->sortorder + $i) { 1044 $course->sortorder = $cat->sortorder + $i; 1045 $DB->update_record_raw('course', $course, true); 1046 $cacheevents['changesincourse'] = true; 1047 } 1048 $i++; 1049 } 1050 } 1051 1052 // advise all caches that need to be rebuilt 1053 foreach (array_keys($cacheevents) as $event) { 1054 cache_helper::purge_by_event($event); 1055 } 1056 } 1057 1058 /** 1059 * Internal recursive category verification function, do not use directly! 1060 * 1061 * @todo Document the arguments of this function better 1062 * 1063 * @global object 1064 * @uses MAX_COURSES_IN_CATEGORY 1065 * @uses CONTEXT_COURSECAT 1066 * @param array $children 1067 * @param int $sortorder 1068 * @param string $parent 1069 * @param int $depth 1070 * @param string $path 1071 * @param array $fixcontexts 1072 * @return bool if changes were made 1073 */ 1074 function _fix_course_cats($children, &$sortorder, $parent, $depth, $path, &$fixcontexts) { 1075 global $DB; 1076 1077 $depth++; 1078 $changesmade = false; 1079 1080 foreach ($children as $cat) { 1081 $sortorder = $sortorder + MAX_COURSES_IN_CATEGORY; 1082 $update = false; 1083 if ($parent != $cat->parent or $depth != $cat->depth or $path.'/'.$cat->id != $cat->path) { 1084 $cat->parent = $parent; 1085 $cat->depth = $depth; 1086 $cat->path = $path.'/'.$cat->id; 1087 $update = true; 1088 1089 // make sure context caches are rebuild and dirty contexts marked 1090 $context = context_coursecat::instance($cat->id); 1091 $fixcontexts[$context->id] = $context; 1092 } 1093 if ($cat->sortorder != $sortorder) { 1094 $cat->sortorder = $sortorder; 1095 $update = true; 1096 } 1097 if ($update) { 1098 $DB->update_record('course_categories', $cat, true); 1099 $changesmade = true; 1100 } 1101 if (isset($cat->children)) { 1102 if (_fix_course_cats($cat->children, $sortorder, $cat->id, $cat->depth, $cat->path, $fixcontexts)) { 1103 $changesmade = true; 1104 } 1105 } 1106 } 1107 return $changesmade; 1108 } 1109 1110 /** 1111 * List of remote courses that a user has access to via MNET. 1112 * Works only on the IDP 1113 * 1114 * @global object 1115 * @global object 1116 * @param int @userid The user id to get remote courses for 1117 * @return array Array of {@link $COURSE} of course objects 1118 */ 1119 function get_my_remotecourses($userid=0) { 1120 global $DB, $USER; 1121 1122 if (empty($userid)) { 1123 $userid = $USER->id; 1124 } 1125 1126 // we can not use SELECT DISTINCT + text field (summary) because of MS SQL and Oracle, subselect used therefore 1127 $sql = "SELECT c.id, c.remoteid, c.shortname, c.fullname, 1128 c.hostid, c.summary, c.summaryformat, c.categoryname AS cat_name, 1129 h.name AS hostname 1130 FROM {mnetservice_enrol_courses} c 1131 JOIN (SELECT DISTINCT hostid, remotecourseid 1132 FROM {mnetservice_enrol_enrolments} 1133 WHERE userid = ? 1134 ) e ON (e.hostid = c.hostid AND e.remotecourseid = c.remoteid) 1135 JOIN {mnet_host} h ON h.id = c.hostid"; 1136 1137 return $DB->get_records_sql($sql, array($userid)); 1138 } 1139 1140 /** 1141 * List of remote hosts that a user has access to via MNET. 1142 * Works on the SP 1143 * 1144 * @global object 1145 * @global object 1146 * @return array|bool Array of host objects or false 1147 */ 1148 function get_my_remotehosts() { 1149 global $CFG, $USER; 1150 1151 if ($USER->mnethostid == $CFG->mnet_localhost_id) { 1152 return false; // Return nothing on the IDP 1153 } 1154 if (!empty($USER->mnet_foreign_host_array) && is_array($USER->mnet_foreign_host_array)) { 1155 return $USER->mnet_foreign_host_array; 1156 } 1157 return false; 1158 } 1159 1160 /** 1161 * This function creates a default separated/connected scale 1162 * 1163 * This function creates a default separated/connected scale 1164 * so there's something in the database. The locations of 1165 * strings and files is a bit odd, but this is because we 1166 * need to maintain backward compatibility with many different 1167 * existing language translations and older sites. 1168 * 1169 * @global object 1170 * @return void 1171 */ 1172 function make_default_scale() { 1173 global $DB; 1174 1175 $defaultscale = new stdClass(); 1176 $defaultscale->courseid = 0; 1177 $defaultscale->userid = 0; 1178 $defaultscale->name = get_string('separateandconnected'); 1179 $defaultscale->description = get_string('separateandconnectedinfo'); 1180 $defaultscale->scale = get_string('postrating1', 'forum').','. 1181 get_string('postrating2', 'forum').','. 1182 get_string('postrating3', 'forum'); 1183 $defaultscale->timemodified = time(); 1184 1185 $defaultscale->id = $DB->insert_record('scale', $defaultscale); 1186 $DB->execute("UPDATE {forum} SET scale = ?", array($defaultscale->id)); 1187 } 1188 1189 1190 /** 1191 * Returns a menu of all available scales from the site as well as the given course 1192 * 1193 * @global object 1194 * @param int $courseid The id of the course as found in the 'course' table. 1195 * @return array 1196 */ 1197 function get_scales_menu($courseid=0) { 1198 global $DB; 1199 1200 $sql = "SELECT id, name 1201 FROM {scale} 1202 WHERE courseid = 0 or courseid = ? 1203 ORDER BY courseid ASC, name ASC"; 1204 $params = array($courseid); 1205 1206 if ($scales = $DB->get_records_sql_menu($sql, $params)) { 1207 return $scales; 1208 } 1209 1210 make_default_scale(); 1211 1212 return $DB->get_records_sql_menu($sql, $params); 1213 } 1214 1215 1216 1217 /** 1218 * Given a set of timezone records, put them in the database, replacing what is there 1219 * 1220 * @global object 1221 * @param array $timezones An array of timezone records 1222 * @return void 1223 */ 1224 function update_timezone_records($timezones) { 1225 global $DB; 1226 1227 /// Clear out all the old stuff 1228 $DB->delete_records('timezone'); 1229 1230 /// Insert all the new stuff 1231 foreach ($timezones as $timezone) { 1232 if (is_array($timezone)) { 1233 $timezone = (object)$timezone; 1234 } 1235 $DB->insert_record('timezone', $timezone); 1236 } 1237 } 1238 1239 /** 1240 * Increment standard revision field. 1241 * 1242 * The revision are based on current time and are incrementing. 1243 * There is a protection for runaway revisions, it may not go further than 1244 * one hour into future. 1245 * 1246 * The field has to be XMLDB_TYPE_INTEGER with size 10. 1247 * 1248 * @param string $table 1249 * @param string $field name of the field containing revision 1250 * @param string $select use empty string when updating all records 1251 * @param array $params optional select parameters 1252 */ 1253 function increment_revision_number($table, $field, $select, array $params = null) { 1254 global $DB; 1255 1256 $now = time(); 1257 $sql = "UPDATE {{$table}} 1258 SET $field = (CASE 1259 WHEN $field IS NULL THEN $now 1260 WHEN $field < $now THEN $now 1261 WHEN $field > $now + 3600 THEN $now 1262 ELSE $field + 1 END)"; 1263 if ($select) { 1264 $sql = $sql . " WHERE $select"; 1265 } 1266 $DB->execute($sql, $params); 1267 } 1268 1269 1270 /// MODULE FUNCTIONS ///////////////////////////////////////////////// 1271 1272 /** 1273 * Just gets a raw list of all modules in a course 1274 * 1275 * @global object 1276 * @param int $courseid The id of the course as found in the 'course' table. 1277 * @return array 1278 */ 1279 function get_course_mods($courseid) { 1280 global $DB; 1281 1282 if (empty($courseid)) { 1283 return false; // avoid warnings 1284 } 1285 1286 return $DB->get_records_sql("SELECT cm.*, m.name as modname 1287 FROM {modules} m, {course_modules} cm 1288 WHERE cm.course = ? AND cm.module = m.id AND m.visible = 1", 1289 array($courseid)); // no disabled mods 1290 } 1291 1292 1293 /** 1294 * Given an id of a course module, finds the coursemodule description 1295 * 1296 * Please note that this function performs 1-2 DB queries. When possible use cached 1297 * course modinfo. For example get_fast_modinfo($courseorid)->get_cm($cmid) 1298 * See also {@link cm_info::get_course_module_record()} 1299 * 1300 * @global object 1301 * @param string $modulename name of module type, eg. resource, assignment,... (optional, slower and less safe if not specified) 1302 * @param int $cmid course module id (id in course_modules table) 1303 * @param int $courseid optional course id for extra validation 1304 * @param bool $sectionnum include relative section number (0,1,2 ...) 1305 * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; 1306 * IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended); 1307 * MUST_EXIST means throw exception if no record or multiple records found 1308 * @return stdClass 1309 */ 1310 function get_coursemodule_from_id($modulename, $cmid, $courseid=0, $sectionnum=false, $strictness=IGNORE_MISSING) { 1311 global $DB; 1312 1313 $params = array('cmid'=>$cmid); 1314 1315 if (!$modulename) { 1316 if (!$modulename = $DB->get_field_sql("SELECT md.name 1317 FROM {modules} md 1318 JOIN {course_modules} cm ON cm.module = md.id 1319 WHERE cm.id = :cmid", $params, $strictness)) { 1320 return false; 1321 } 1322 } else { 1323 if (!core_component::is_valid_plugin_name('mod', $modulename)) { 1324 throw new coding_exception('Invalid modulename parameter'); 1325 } 1326 } 1327 1328 $params['modulename'] = $modulename; 1329 1330 $courseselect = ""; 1331 $sectionfield = ""; 1332 $sectionjoin = ""; 1333 1334 if ($courseid) { 1335 $courseselect = "AND cm.course = :courseid"; 1336 $params['courseid'] = $courseid; 1337 } 1338 1339 if ($sectionnum) { 1340 $sectionfield = ", cw.section AS sectionnum"; 1341 $sectionjoin = "LEFT JOIN {course_sections} cw ON cw.id = cm.section"; 1342 } 1343 1344 $sql = "SELECT cm.*, m.name, md.name AS modname $sectionfield 1345 FROM {course_modules} cm 1346 JOIN {modules} md ON md.id = cm.module 1347 JOIN {".$modulename."} m ON m.id = cm.instance 1348 $sectionjoin 1349 WHERE cm.id = :cmid AND md.name = :modulename 1350 $courseselect"; 1351 1352 return $DB->get_record_sql($sql, $params, $strictness); 1353 } 1354 1355 /** 1356 * Given an instance number of a module, finds the coursemodule description 1357 * 1358 * Please note that this function performs DB query. When possible use cached course 1359 * modinfo. For example get_fast_modinfo($courseorid)->instances[$modulename][$instance] 1360 * See also {@link cm_info::get_course_module_record()} 1361 * 1362 * @global object 1363 * @param string $modulename name of module type, eg. resource, assignment,... 1364 * @param int $instance module instance number (id in resource, assignment etc. table) 1365 * @param int $courseid optional course id for extra validation 1366 * @param bool $sectionnum include relative section number (0,1,2 ...) 1367 * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; 1368 * IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended); 1369 * MUST_EXIST means throw exception if no record or multiple records found 1370 * @return stdClass 1371 */ 1372 function get_coursemodule_from_instance($modulename, $instance, $courseid=0, $sectionnum=false, $strictness=IGNORE_MISSING) { 1373 global $DB; 1374 1375 if (!core_component::is_valid_plugin_name('mod', $modulename)) { 1376 throw new coding_exception('Invalid modulename parameter'); 1377 } 1378 1379 $params = array('instance'=>$instance, 'modulename'=>$modulename); 1380 1381 $courseselect = ""; 1382 $sectionfield = ""; 1383 $sectionjoin = ""; 1384 1385 if ($courseid) { 1386 $courseselect = "AND cm.course = :courseid"; 1387 $params['courseid'] = $courseid; 1388 } 1389 1390 if ($sectionnum) { 1391 $sectionfield = ", cw.section AS sectionnum"; 1392 $sectionjoin = "LEFT JOIN {course_sections} cw ON cw.id = cm.section"; 1393 } 1394 1395 $sql = "SELECT cm.*, m.name, md.name AS modname $sectionfield 1396 FROM {course_modules} cm 1397 JOIN {modules} md ON md.id = cm.module 1398 JOIN {".$modulename."} m ON m.id = cm.instance 1399 $sectionjoin 1400 WHERE m.id = :instance AND md.name = :modulename 1401 $courseselect"; 1402 1403 return $DB->get_record_sql($sql, $params, $strictness); 1404 } 1405 1406 /** 1407 * Returns all course modules of given activity in course 1408 * 1409 * @param string $modulename The module name (forum, quiz, etc.) 1410 * @param int $courseid The course id to get modules for 1411 * @param string $extrafields extra fields starting with m. 1412 * @return array Array of results 1413 */ 1414 function get_coursemodules_in_course($modulename, $courseid, $extrafields='') { 1415 global $DB; 1416 1417 if (!core_component::is_valid_plugin_name('mod', $modulename)) { 1418 throw new coding_exception('Invalid modulename parameter'); 1419 } 1420 1421 if (!empty($extrafields)) { 1422 $extrafields = ", $extrafields"; 1423 } 1424 $params = array(); 1425 $params['courseid'] = $courseid; 1426 $params['modulename'] = $modulename; 1427 1428 1429 return $DB->get_records_sql("SELECT cm.*, m.name, md.name as modname $extrafields 1430 FROM {course_modules} cm, {modules} md, {".$modulename."} m 1431 WHERE cm.course = :courseid AND 1432 cm.instance = m.id AND 1433 md.name = :modulename AND 1434 md.id = cm.module", $params); 1435 } 1436 1437 /** 1438 * Returns an array of all the active instances of a particular module in given courses, sorted in the order they are defined 1439 * 1440 * Returns an array of all the active instances of a particular 1441 * module in given courses, sorted in the order they are defined 1442 * in the course. Returns an empty array on any errors. 1443 * 1444 * The returned objects includle the columns cw.section, cm.visible, 1445 * cm.groupmode, and cm.groupingid, and are indexed by cm.id. 1446 * 1447 * @global object 1448 * @global object 1449 * @param string $modulename The name of the module to get instances for 1450 * @param array $courses an array of course objects. 1451 * @param int $userid 1452 * @param int $includeinvisible 1453 * @return array of module instance objects, including some extra fields from the course_modules 1454 * and course_sections tables, or an empty array if an error occurred. 1455 */ 1456 function get_all_instances_in_courses($modulename, $courses, $userid=NULL, $includeinvisible=false) { 1457 global $CFG, $DB; 1458 1459 if (!core_component::is_valid_plugin_name('mod', $modulename)) { 1460 throw new coding_exception('Invalid modulename parameter'); 1461 } 1462 1463 $outputarray = array(); 1464 1465 if (empty($courses) || !is_array($courses) || count($courses) == 0) { 1466 return $outputarray; 1467 } 1468 1469 list($coursessql, $params) = $DB->get_in_or_equal(array_keys($courses), SQL_PARAMS_NAMED, 'c0'); 1470 $params['modulename'] = $modulename; 1471 1472 if (!$rawmods = $DB->get_records_sql("SELECT cm.id AS coursemodule, m.*, cw.section, cm.visible AS visible, 1473 cm.groupmode, cm.groupingid 1474 FROM {course_modules} cm, {course_sections} cw, {modules} md, 1475 {".$modulename."} m 1476 WHERE cm.course $coursessql AND 1477 cm.instance = m.id AND 1478 cm.section = cw.id AND 1479 md.name = :modulename AND 1480 md.id = cm.module", $params)) { 1481 return $outputarray; 1482 } 1483 1484 foreach ($courses as $course) { 1485 $modinfo = get_fast_modinfo($course, $userid); 1486 1487 if (empty($modinfo->instances[$modulename])) { 1488 continue; 1489 } 1490 1491 foreach ($modinfo->instances[$modulename] as $cm) { 1492 if (!$includeinvisible and !$cm->uservisible) { 1493 continue; 1494 } 1495 if (!isset($rawmods[$cm->id])) { 1496 continue; 1497 } 1498 $instance = $rawmods[$cm->id]; 1499 if (!empty($cm->extra)) { 1500 $instance->extra = $cm->extra; 1501 } 1502 $outputarray[] = $instance; 1503 } 1504 } 1505 1506 return $outputarray; 1507 } 1508 1509 /** 1510 * Returns an array of all the active instances of a particular module in a given course, 1511 * sorted in the order they are defined. 1512 * 1513 * Returns an array of all the active instances of a particular 1514 * module in a given course, sorted in the order they are defined 1515 * in the course. Returns an empty array on any errors. 1516 * 1517 * The returned objects includle the columns cw.section, cm.visible, 1518 * cm.groupmode, and cm.groupingid, and are indexed by cm.id. 1519 * 1520 * Simply calls {@link all_instances_in_courses()} with a single provided course 1521 * 1522 * @param string $modulename The name of the module to get instances for 1523 * @param object $course The course obect. 1524 * @return array of module instance objects, including some extra fields from the course_modules 1525 * and course_sections tables, or an empty array if an error occurred. 1526 * @param int $userid 1527 * @param int $includeinvisible 1528 */ 1529 function get_all_instances_in_course($modulename, $course, $userid=NULL, $includeinvisible=false) { 1530 return get_all_instances_in_courses($modulename, array($course->id => $course), $userid, $includeinvisible); 1531 } 1532 1533 1534 /** 1535 * Determine whether a module instance is visible within a course 1536 * 1537 * Given a valid module object with info about the id and course, 1538 * and the module's type (eg "forum") returns whether the object 1539 * is visible or not according to the 'eye' icon only. 1540 * 1541 * NOTE: This does NOT take into account visibility to a particular user. 1542 * To get visibility access for a specific user, use get_fast_modinfo, get a 1543 * cm_info object from this, and check the ->uservisible property; or use 1544 * the \core_availability\info_module::is_user_visible() static function. 1545 * 1546 * @global object 1547 1548 * @param $moduletype Name of the module eg 'forum' 1549 * @param $module Object which is the instance of the module 1550 * @return bool Success 1551 */ 1552 function instance_is_visible($moduletype, $module) { 1553 global $DB; 1554 1555 if (!empty($module->id)) { 1556 $params = array('courseid'=>$module->course, 'moduletype'=>$moduletype, 'moduleid'=>$module->id); 1557 if ($records = $DB->get_records_sql("SELECT cm.instance, cm.visible, cm.groupingid, cm.id, cm.course 1558 FROM {course_modules} cm, {modules} m 1559 WHERE cm.course = :courseid AND 1560 cm.module = m.id AND 1561 m.name = :moduletype AND 1562 cm.instance = :moduleid", $params)) { 1563 1564 foreach ($records as $record) { // there should only be one - use the first one 1565 return $record->visible; 1566 } 1567 } 1568 } 1569 return true; // visible by default! 1570 } 1571 1572 1573 /// LOG FUNCTIONS ///////////////////////////////////////////////////// 1574 1575 /** 1576 * Get instance of log manager. 1577 * 1578 * @param bool $forcereload 1579 * @return \core\log\manager 1580 */ 1581 function get_log_manager($forcereload = false) { 1582 /** @var \core\log\manager $singleton */ 1583 static $singleton = null; 1584 1585 if ($forcereload and isset($singleton)) { 1586 $singleton->dispose(); 1587 $singleton = null; 1588 } 1589 1590 if (isset($singleton)) { 1591 return $singleton; 1592 } 1593 1594 $classname = '\tool_log\log\manager'; 1595 if (defined('LOG_MANAGER_CLASS')) { 1596 $classname = LOG_MANAGER_CLASS; 1597 } 1598 1599 if (!class_exists($classname)) { 1600 if (!empty($classname)) { 1601 debugging("Cannot find log manager class '$classname'.", DEBUG_DEVELOPER); 1602 } 1603 $classname = '\core\log\dummy_manager'; 1604 } 1605 1606 $singleton = new $classname(); 1607 return $singleton; 1608 } 1609 1610 /** 1611 * Add an entry to the config log table. 1612 * 1613 * These are "action" focussed rather than web server hits, 1614 * and provide a way to easily reconstruct changes to Moodle configuration. 1615 * 1616 * @package core 1617 * @category log 1618 * @global moodle_database $DB 1619 * @global stdClass $USER 1620 * @param string $name The name of the configuration change action 1621 For example 'filter_active' when activating or deactivating a filter 1622 * @param string $oldvalue The config setting's previous value 1623 * @param string $value The config setting's new value 1624 * @param string $plugin Plugin name, for example a filter name when changing filter configuration 1625 * @return void 1626 */ 1627 function add_to_config_log($name, $oldvalue, $value, $plugin) { 1628 global $USER, $DB; 1629 1630 $log = new stdClass(); 1631 $log->userid = during_initial_install() ? 0 :$USER->id; // 0 as user id during install 1632 $log->timemodified = time(); 1633 $log->name = $name; 1634 $log->oldvalue = $oldvalue; 1635 $log->value = $value; 1636 $log->plugin = $plugin; 1637 $DB->insert_record('config_log', $log); 1638 } 1639 1640 /** 1641 * Store user last access times - called when use enters a course or site 1642 * 1643 * @package core 1644 * @category log 1645 * @global stdClass $USER 1646 * @global stdClass $CFG 1647 * @global moodle_database $DB 1648 * @uses LASTACCESS_UPDATE_SECS 1649 * @uses SITEID 1650 * @param int $courseid empty courseid means site 1651 * @return void 1652 */ 1653 function user_accesstime_log($courseid=0) { 1654 global $USER, $CFG, $DB; 1655 1656 if (!isloggedin() or \core\session\manager::is_loggedinas()) { 1657 // no access tracking 1658 return; 1659 } 1660 1661 if (isguestuser()) { 1662 // Do not update guest access times/ips for performance. 1663 return; 1664 } 1665 1666 if (empty($courseid)) { 1667 $courseid = SITEID; 1668 } 1669 1670 $timenow = time(); 1671 1672 /// Store site lastaccess time for the current user 1673 if ($timenow - $USER->lastaccess > LASTACCESS_UPDATE_SECS) { 1674 /// Update $USER->lastaccess for next checks 1675 $USER->lastaccess = $timenow; 1676 1677 $last = new stdClass(); 1678 $last->id = $USER->id; 1679 $last->lastip = getremoteaddr(); 1680 $last->lastaccess = $timenow; 1681 1682 $DB->update_record_raw('user', $last); 1683 } 1684 1685 if ($courseid == SITEID) { 1686 /// no user_lastaccess for frontpage 1687 return; 1688 } 1689 1690 /// Store course lastaccess times for the current user 1691 if (empty($USER->currentcourseaccess[$courseid]) or ($timenow - $USER->currentcourseaccess[$courseid] > LASTACCESS_UPDATE_SECS)) { 1692 1693 $lastaccess = $DB->get_field('user_lastaccess', 'timeaccess', array('userid'=>$USER->id, 'courseid'=>$courseid)); 1694 1695 if ($lastaccess === false) { 1696 // Update course lastaccess for next checks 1697 $USER->currentcourseaccess[$courseid] = $timenow; 1698 1699 $last = new stdClass(); 1700 $last->userid = $USER->id; 1701 $last->courseid = $courseid; 1702 $last->timeaccess = $timenow; 1703 $DB->insert_record_raw('user_lastaccess', $last, false); 1704 1705 } else if ($timenow - $lastaccess < LASTACCESS_UPDATE_SECS) { 1706 // no need to update now, it was updated recently in concurrent login ;-) 1707 1708 } else { 1709 // Update course lastaccess for next checks 1710 $USER->currentcourseaccess[$courseid] = $timenow; 1711 1712 $DB->set_field('user_lastaccess', 'timeaccess', $timenow, array('userid'=>$USER->id, 'courseid'=>$courseid)); 1713 } 1714 } 1715 } 1716 1717 /** 1718 * Select all log records based on SQL criteria 1719 * 1720 * @package core 1721 * @category log 1722 * @global moodle_database $DB 1723 * @param string $select SQL select criteria 1724 * @param array $params named sql type params 1725 * @param string $order SQL order by clause to sort the records returned 1726 * @param string $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set) 1727 * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set) 1728 * @param int $totalcount Passed in by reference. 1729 * @return array 1730 */ 1731 function get_logs($select, array $params=null, $order='l.time DESC', $limitfrom='', $limitnum='', &$totalcount) { 1732 global $DB; 1733 1734 if ($order) { 1735 $order = "ORDER BY $order"; 1736 } 1737 1738 $selectsql = ""; 1739 $countsql = ""; 1740 1741 if ($select) { 1742 $select = "WHERE $select"; 1743 } 1744 1745 $sql = "SELECT COUNT(*) 1746 FROM {log} l 1747 $select"; 1748 1749 $totalcount = $DB->count_records_sql($sql, $params); 1750 $allnames = get_all_user_name_fields(true, 'u'); 1751 $sql = "SELECT l.*, $allnames, u.picture 1752 FROM {log} l 1753 LEFT JOIN {user} u ON l.userid = u.id 1754 $select 1755 $order"; 1756 1757 return $DB->get_records_sql($sql, $params, $limitfrom, $limitnum) ; 1758 } 1759 1760 1761 /** 1762 * Select all log records for a given course and user 1763 * 1764 * @package core 1765 * @category log 1766 * @global moodle_database $DB 1767 * @uses DAYSECS 1768 * @param int $userid The id of the user as found in the 'user' table. 1769 * @param int $courseid The id of the course as found in the 'course' table. 1770 * @param string $coursestart unix timestamp representing course start date and time. 1771 * @return array 1772 */ 1773 function get_logs_usercourse($userid, $courseid, $coursestart) { 1774 global $DB; 1775 1776 $params = array(); 1777 1778 $courseselect = ''; 1779 if ($courseid) { 1780 $courseselect = "AND course = :courseid"; 1781 $params['courseid'] = $courseid; 1782 } 1783 $params['userid'] = $userid; 1784 $$coursestart = (int)$coursestart; // note: unfortunately pg complains if you use name parameter or column alias in GROUP BY 1785 1786 return $DB->get_records_sql("SELECT FLOOR((time - $coursestart)/". DAYSECS .") AS day, COUNT(*) AS num 1787 FROM {log} 1788 WHERE userid = :userid 1789 AND time > $coursestart $courseselect 1790 GROUP BY FLOOR((time - $coursestart)/". DAYSECS .")", $params); 1791 } 1792 1793 /** 1794 * Select all log records for a given course, user, and day 1795 * 1796 * @package core 1797 * @category log 1798 * @global moodle_database $DB 1799 * @uses HOURSECS 1800 * @param int $userid The id of the user as found in the 'user' table. 1801 * @param int $courseid The id of the course as found in the 'course' table. 1802 * @param string $daystart unix timestamp of the start of the day for which the logs needs to be retrived 1803 * @return array 1804 */ 1805 function get_logs_userday($userid, $courseid, $daystart) { 1806 global $DB; 1807 1808 $params = array('userid'=>$userid); 1809 1810 $courseselect = ''; 1811 if ($courseid) { 1812 $courseselect = "AND course = :courseid"; 1813 $params['courseid'] = $courseid; 1814 } 1815 $daystart = (int)$daystart; // note: unfortunately pg complains if you use name parameter or column alias in GROUP BY 1816 1817 return $DB->get_records_sql("SELECT FLOOR((time - $daystart)/". HOURSECS .") AS hour, COUNT(*) AS num 1818 FROM {log} 1819 WHERE userid = :userid 1820 AND time > $daystart $courseselect 1821 GROUP BY FLOOR((time - $daystart)/". HOURSECS .") ", $params); 1822 } 1823 1824 /// GENERAL HELPFUL THINGS /////////////////////////////////// 1825 1826 /** 1827 * Dumps a given object's information for debugging purposes 1828 * 1829 * When used in a CLI script, the object's information is written to the standard 1830 * error output stream. When used in a web script, the object is dumped to a 1831 * pre-formatted block with the "notifytiny" CSS class. 1832 * 1833 * @param mixed $object The data to be printed 1834 * @return void output is echo'd 1835 */ 1836 function print_object($object) { 1837 1838 // we may need a lot of memory here 1839 raise_memory_limit(MEMORY_EXTRA); 1840 1841 if (CLI_SCRIPT) { 1842 fwrite(STDERR, print_r($object, true)); 1843 fwrite(STDERR, PHP_EOL); 1844 } else { 1845 echo html_writer::tag('pre', s(print_r($object, true)), array('class' => 'notifytiny')); 1846 } 1847 } 1848 1849 /** 1850 * This function is the official hook inside XMLDB stuff to delegate its debug to one 1851 * external function. 1852 * 1853 * Any script can avoid calls to this function by defining XMLDB_SKIP_DEBUG_HOOK before 1854 * using XMLDB classes. Obviously, also, if this function doesn't exist, it isn't invoked ;-) 1855 * 1856 * @uses DEBUG_DEVELOPER 1857 * @param string $message string contains the error message 1858 * @param object $object object XMLDB object that fired the debug 1859 */ 1860 function xmldb_debug($message, $object) { 1861 1862 debugging($message, DEBUG_DEVELOPER); 1863 } 1864 1865 /** 1866 * @global object 1867 * @uses CONTEXT_COURSECAT 1868 * @return boolean Whether the user can create courses in any category in the system. 1869 */ 1870 function user_can_create_courses() { 1871 global $DB; 1872 $catsrs = $DB->get_recordset('course_categories'); 1873 foreach ($catsrs as $cat) { 1874 if (has_capability('moodle/course:create', context_coursecat::instance($cat->id))) { 1875 $catsrs->close(); 1876 return true; 1877 } 1878 } 1879 $catsrs->close(); 1880 return false; 1881 } 1882 1883 /** 1884 * This method can update the values in mulitple database rows for a colum with 1885 * a unique index, without violating that constraint. 1886 * 1887 * Suppose we have a table with a unique index on (otherid, sortorder), and 1888 * for a particular value of otherid, we want to change all the sort orders. 1889 * You have to do this carefully or you will violate the unique index at some time. 1890 * This method takes care of the details for you. 1891 * 1892 * Note that, it is the responsibility of the caller to make sure that the 1893 * requested rename is legal. For example, if you ask for [1 => 2, 2 => 2] 1894 * then you will get a unique key violation error from the database. 1895 * 1896 * @param string $table The database table to modify. 1897 * @param string $field the field that contains the values we are going to change. 1898 * @param array $newvalues oldvalue => newvalue how to change the values. 1899 * E.g. [1 => 4, 2 => 1, 3 => 3, 4 => 2]. 1900 * @param array $otherconditions array fieldname => requestedvalue extra WHERE clause 1901 * conditions to restrict which rows are affected. E.g. array('otherid' => 123). 1902 * @param int $unusedvalue (defaults to -1) a value that is never used in $ordercol. 1903 */ 1904 function update_field_with_unique_index($table, $field, array $newvalues, 1905 array $otherconditions, $unusedvalue = -1) { 1906 global $DB; 1907 $safechanges = decompose_update_into_safe_changes($newvalues, $unusedvalue); 1908 1909 $transaction = $DB->start_delegated_transaction(); 1910 foreach ($safechanges as $change) { 1911 list($from, $to) = $change; 1912 $otherconditions[$field] = $from; 1913 $DB->set_field($table, $field, $to, $otherconditions); 1914 } 1915 $transaction->allow_commit(); 1916 } 1917 1918 /** 1919 * Helper used by {@link update_field_with_unique_index()}. Given a desired 1920 * set of changes, break them down into single udpates that can be done one at 1921 * a time without breaking any unique index constraints. 1922 * 1923 * Suppose the input is array(1 => 2, 2 => 1) and -1. Then the output will be 1924 * array (array(1, -1), array(2, 1), array(-1, 2)). This function solves this 1925 * problem in the general case, not just for simple swaps. The unit tests give 1926 * more examples. 1927 * 1928 * Note that, it is the responsibility of the caller to make sure that the 1929 * requested rename is legal. For example, if you ask for something impossible 1930 * like array(1 => 2, 2 => 2) then the results are undefined. (You will probably 1931 * get a unique key violation error from the database later.) 1932 * 1933 * @param array $newvalues The desired re-ordering. 1934 * E.g. array(1 => 4, 2 => 1, 3 => 3, 4 => 2). 1935 * @param int $unusedvalue A value that is not currently used. 1936 * @return array A safe way to perform the re-order. An array of two-element 1937 * arrays array($from, $to). 1938 * E.g. array(array(1, -1), array(2, 1), array(4, 2), array(-1, 4)). 1939 */ 1940 function decompose_update_into_safe_changes(array $newvalues, $unusedvalue) { 1941 $nontrivialmap = array(); 1942 foreach ($newvalues as $from => $to) { 1943 if ($from == $unusedvalue || $to == $unusedvalue) { 1944 throw new \coding_exception('Supposedly unused value ' . $unusedvalue . ' is actually used!'); 1945 } 1946 if ($from != $to) { 1947 $nontrivialmap[$from] = $to; 1948 } 1949 } 1950 1951 if (empty($nontrivialmap)) { 1952 return array(); 1953 } 1954 1955 // First we deal with all renames that are not part of cycles. 1956 // This bit is O(n^2) and it ought to be possible to do better, 1957 // but it does not seem worth the effort. 1958 $safechanges = array(); 1959 $nontrivialmapchanged = true; 1960 while ($nontrivialmapchanged) { 1961 $nontrivialmapchanged = false; 1962 1963 foreach ($nontrivialmap as $from => $to) { 1964 if (array_key_exists($to, $nontrivialmap)) { 1965 continue; // Cannot currenly do this rename. 1966 } 1967 // Is safe to do this rename now. 1968 $safechanges[] = array($from, $to); 1969 unset($nontrivialmap[$from]); 1970 $nontrivialmapchanged = true; 1971 } 1972 } 1973 1974 // Are we done? 1975 if (empty($nontrivialmap)) { 1976 return $safechanges; 1977 } 1978 1979 // Now what is left in $nontrivialmap must be a permutation, 1980 // which must be a combination of disjoint cycles. We need to break them. 1981 while (!empty($nontrivialmap)) { 1982 // Extract the first cycle. 1983 reset($nontrivialmap); 1984 $current = $cyclestart = key($nontrivialmap); 1985 $cycle = array(); 1986 do { 1987 $cycle[] = $current; 1988 $next = $nontrivialmap[$current]; 1989 unset($nontrivialmap[$current]); 1990 $current = $next; 1991 } while ($current != $cyclestart); 1992 1993 // Now convert it to a sequence of safe renames by using a temp. 1994 $safechanges[] = array($cyclestart, $unusedvalue); 1995 $cycle[0] = $unusedvalue; 1996 $to = $cyclestart; 1997 while ($from = array_pop($cycle)) { 1998 $safechanges[] = array($from, $to); 1999 $to = $from; 2000 } 2001 } 2002 2003 return $safechanges; 2004 }
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| Generated: Fri Nov 28 20:29:05 2014 | Cross-referenced by PHPXref 0.7.1 |