course/modlib.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 specific to course/modedit.php and course API functions.
  19  * The course API function calling them are course/lib.php:create_module() and update_module().
  20  * This file has been created has an alternative solution to a full refactor of course/modedit.php
  21  * in order to create the course API functions.
  22  *
  23  * @copyright 2013 Jerome Mouneyrac
  24  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25  * @package core_course
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die;
  29
  30 require_once($CFG->dirroot.'/course/lib.php');
  31
  32 /**
  33  * Add course module.
  34  *
  35  * The function does not check user capabilities.
  36  * The function creates course module, module instance, add the module to the correct section.
  37  * It also trigger common action that need to be done after adding/updating a module.
  38  *
  39  * @param object $moduleinfo the moudle data
  40  * @param object $course the course of the module
  41  * @param object $mform this is required by an existing hack to deal with files during MODULENAME_add_instance()
  42  * @return object the updated module info
  43  */
  44 function add_moduleinfo($moduleinfo, $course, $mform = null) {
  45     global $DB, $CFG;
  46
  47     // Attempt to include module library before we make any changes to DB.
  48     include_modulelib($moduleinfo->modulename);
  49
  50     $moduleinfo->course = $course->id;
  51     $moduleinfo = set_moduleinfo_defaults($moduleinfo);
  52
  53     if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
  54         $moduleinfo->groupmode = 0; // Do not set groupmode.
  55     }
  56
  57     // First add course_module record because we need the context.
  58     $newcm = new stdClass();
  59     $newcm->course           = $course->id;
  60     $newcm->module           = $moduleinfo->module;
  61     $newcm->instance         = 0; // Not known yet, will be updated later (this is similar to restore code).
  62     $newcm->visible          = $moduleinfo->visible;
  63     $newcm->visibleold       = $moduleinfo->visible;
  64     if (isset($moduleinfo->cmidnumber)) {
  65         $newcm->idnumber         = $moduleinfo->cmidnumber;
  66     }
  67     $newcm->groupmode        = $moduleinfo->groupmode;
  68     $newcm->groupingid       = $moduleinfo->groupingid;
  69     $completion = new completion_info($course);
  70     if ($completion->is_enabled()) {
  71         $newcm->completion                = $moduleinfo->completion;
  72         $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
  73         $newcm->completionview            = $moduleinfo->completionview;
  74         $newcm->completionexpected        = $moduleinfo->completionexpected;
  75     }
  76     if(!empty($CFG->enableavailability)) {
  77         // This code is used both when submitting the form, which uses a long
  78         // name to avoid clashes, and by unit test code which uses the real
  79         // name in the table.
  80         $newcm->availability = null;
  81         if (property_exists($moduleinfo, 'availabilityconditionsjson')) {
  82             if ($moduleinfo->availabilityconditionsjson !== '') {
  83                 $newcm->availability = $moduleinfo->availabilityconditionsjson;
  84             }
  85         } else if (property_exists($moduleinfo, 'availability')) {
  86             $newcm->availability = $moduleinfo->availability;
  87         }
  88         // If there is any availability data, verify it.
  89         if ($newcm->availability) {
  90             $tree = new \core_availability\tree(json_decode($newcm->availability));
  91             // Save time and database space by setting null if the only data
  92             // is an empty tree.
  93             if ($tree->is_empty()) {
  94                 $newcm->availability = null;
  95             }
  96         }
  97     }
  98     if (isset($moduleinfo->showdescription)) {
  99         $newcm->showdescription = $moduleinfo->showdescription;
 100     } else {
 101         $newcm->showdescription = 0;
 102     }
 103
 104     // From this point we make database changes, so start transaction.
 105     $transaction = $DB->start_delegated_transaction();
 106
 107     if (!$moduleinfo->coursemodule = add_course_module($newcm)) {
 108         print_error('cannotaddcoursemodule');
 109     }
 110
 111     if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true) &&
 112             isset($moduleinfo->introeditor)) {
 113         $introeditor = $moduleinfo->introeditor;
 114         unset($moduleinfo->introeditor);
 115         $moduleinfo->intro       = $introeditor['text'];
 116         $moduleinfo->introformat = $introeditor['format'];
 117     }
 118
 119     $addinstancefunction    = $moduleinfo->modulename."_add_instance";
 120     try {
 121         $returnfromfunc = $addinstancefunction($moduleinfo, $mform);
 122     } catch (moodle_exception $e) {
 123         $returnfromfunc = $e;
 124     }
 125     if (!$returnfromfunc or !is_number($returnfromfunc)) {
 126         // Undo everything we can. This is not necessary for databases which
 127         // support transactions, but improves consistency for other databases.
 128         $modcontext = context_module::instance($moduleinfo->coursemodule);
 129         context_helper::delete_instance(CONTEXT_MODULE, $moduleinfo->coursemodule);
 130         $DB->delete_records('course_modules', array('id'=>$moduleinfo->coursemodule));
 131
 132         if ($e instanceof moodle_exception) {
 133             throw $e;
 134         } else if (!is_number($returnfromfunc)) {
 135             print_error('invalidfunction', '', course_get_url($course, $moduleinfo->section));
 136         } else {
 137             print_error('cannotaddnewmodule', '', course_get_url($course, $moduleinfo->section), $moduleinfo->modulename);
 138         }
 139     }
 140
 141     $moduleinfo->instance = $returnfromfunc;
 142
 143     $DB->set_field('course_modules', 'instance', $returnfromfunc, array('id'=>$moduleinfo->coursemodule));
 144
 145     // Update embedded links and save files.
 146     $modcontext = context_module::instance($moduleinfo->coursemodule);
 147     if (!empty($introeditor)) {
 148         $moduleinfo->intro = file_save_draft_area_files($introeditor['itemid'], $modcontext->id,
 149                                                       'mod_'.$moduleinfo->modulename, 'intro', 0,
 150                                                       array('subdirs'=>true), $introeditor['text']);
 151         $DB->set_field($moduleinfo->modulename, 'intro', $moduleinfo->intro, array('id'=>$moduleinfo->instance));
 152     }
 153
 154     // Course_modules and course_sections each contain a reference to each other.
 155     // So we have to update one of them twice.
 156     $sectionid = course_add_cm_to_section($course, $moduleinfo->coursemodule, $moduleinfo->section);
 157
 158     // Trigger event based on the action we did.
 159     // Api create_from_cm expects modname and id property, and we don't want to modify $moduleinfo since we are returning it.
 160     $eventdata = clone $moduleinfo;
 161     $eventdata->modname = $eventdata->modulename;
 162     $eventdata->id = $eventdata->coursemodule;
 163     $event = \core\event\course_module_created::create_from_cm($eventdata, $modcontext);
 164     $event->trigger();
 165
 166     $moduleinfo = edit_module_post_actions($moduleinfo, $course);
 167     $transaction->allow_commit();
 168
 169     return $moduleinfo;
 170 }
 171
 172
 173 /**
 174  * Common create/update module module actions that need to be processed as soon as a module is created/updaded.
 175  * For example:create grade parent category, add outcomes, rebuild caches, regrade, save plagiarism settings...
 176  * Please note this api does not trigger events as of MOODLE 2.6. Please trigger events before calling this api.
 177  *
 178  * @param object $moduleinfo the module info
 179  * @param object $course the course of the module
 180  *
 181  * @return object moduleinfo update with grading management info
 182  */
 183 function edit_module_post_actions($moduleinfo, $course) {
 184     global $CFG;
 185     require_once($CFG->libdir.'/gradelib.php');
 186
 187     $modcontext = context_module::instance($moduleinfo->coursemodule);
 188     $hasgrades = plugin_supports('mod', $moduleinfo->modulename, FEATURE_GRADE_HAS_GRADE, false);
 189     $hasoutcomes = plugin_supports('mod', $moduleinfo->modulename, FEATURE_GRADE_OUTCOMES, true);
 190
 191     // Sync idnumber with grade_item.
 192     if ($hasgrades && $grade_item = grade_item::fetch(array('itemtype'=>'mod', 'itemmodule'=>$moduleinfo->modulename,
 193                  'iteminstance'=>$moduleinfo->instance, 'itemnumber'=>0, 'courseid'=>$course->id))) {
 194         if ($grade_item->idnumber != $moduleinfo->cmidnumber) {
 195             $grade_item->idnumber = $moduleinfo->cmidnumber;
 196             $grade_item->update();
 197         }
 198     }
 199
 200     if ($hasgrades) {
 201         $items = grade_item::fetch_all(array('itemtype'=>'mod', 'itemmodule'=>$moduleinfo->modulename,
 202                                          'iteminstance'=>$moduleinfo->instance, 'courseid'=>$course->id));
 203     } else {
 204         $items = array();
 205     }
 206
 207     // Create parent category if requested and move to correct parent category.
 208     if ($items and isset($moduleinfo->gradecat)) {
 209         if ($moduleinfo->gradecat == -1) {
 210             $grade_category = new grade_category();
 211             $grade_category->courseid = $course->id;
 212             $grade_category->fullname = $moduleinfo->name;
 213             $grade_category->insert();
 214             if ($grade_item) {
 215                 $parent = $grade_item->get_parent_category();
 216                 $grade_category->set_parent($parent->id);
 217             }
 218             $moduleinfo->gradecat = $grade_category->id;
 219         }
 220         $gradecategory = $grade_item->get_parent_category();
 221         foreach ($items as $itemid=>$unused) {
 222             $items[$itemid]->set_parent($moduleinfo->gradecat);
 223             if ($itemid == $grade_item->id) {
 224                 // Use updated grade_item.
 225                 $grade_item = $items[$itemid];
 226             }
 227             if (!empty($moduleinfo->add)) {
 228                 if (grade_category::aggregation_uses_aggregationcoef($gradecategory->aggregation)) {
 229                     if ($gradecategory->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN) {
 230                         $grade_item->aggregationcoef = 1;
 231                     } else {
 232                         $grade_item->aggregationcoef = 0;
 233                     }
 234                     $grade_item->update();
 235                 }
 236             }
 237         }
 238     }
 239
 240     require_once($CFG->libdir.'/grade/grade_outcome.php');
 241     // Add outcomes if requested.
 242     if ($hasoutcomes && $outcomes = grade_outcome::fetch_all_available($course->id)) {
 243         $grade_items = array();
 244
 245         // Outcome grade_item.itemnumber start at 1000, there is nothing above outcomes.
 246         $max_itemnumber = 999;
 247         if ($items) {
 248             foreach($items as $item) {
 249                 if ($item->itemnumber > $max_itemnumber) {
 250                     $max_itemnumber = $item->itemnumber;
 251                 }
 252             }
 253         }
 254
 255         foreach($outcomes as $outcome) {
 256             $elname = 'outcome_'.$outcome->id;
 257
 258             if (property_exists($moduleinfo, $elname) and $moduleinfo->$elname) {
 259                 // So we have a request for new outcome grade item?
 260                 if ($items) {
 261                     $outcomeexists = false;
 262                     foreach($items as $item) {
 263                         if ($item->outcomeid == $outcome->id) {
 264                             $outcomeexists = true;
 265                             break;
 266                         }
 267                     }
 268                     if ($outcomeexists) {
 269                         continue;
 270                     }
 271                 }
 272
 273                 $max_itemnumber++;
 274
 275                 $outcome_item = new grade_item();
 276                 $outcome_item->courseid     = $course->id;
 277                 $outcome_item->itemtype     = 'mod';
 278                 $outcome_item->itemmodule   = $moduleinfo->modulename;
 279                 $outcome_item->iteminstance = $moduleinfo->instance;
 280                 $outcome_item->itemnumber   = $max_itemnumber;
 281                 $outcome_item->itemname     = $outcome->fullname;
 282                 $outcome_item->outcomeid    = $outcome->id;
 283                 $outcome_item->gradetype    = GRADE_TYPE_SCALE;
 284                 $outcome_item->scaleid      = $outcome->scaleid;
 285                 $outcome_item->insert();
 286
 287                 // Move the new outcome into correct category and fix sortorder if needed.
 288                 if ($grade_item) {
 289                     $outcome_item->set_parent($grade_item->categoryid);
 290                     $outcome_item->move_after_sortorder($grade_item->sortorder);
 291
 292                 } else if (isset($moduleinfo->gradecat)) {
 293                     $outcome_item->set_parent($moduleinfo->gradecat);
 294                 }
 295                 $gradecategory = $outcome_item->get_parent_category();
 296                 if ($outcomeexists == false) {
 297                     if (grade_category::aggregation_uses_aggregationcoef($gradecategory->aggregation)) {
 298                         if ($gradecategory->aggregation == GRADE_AGGREGATE_WEIGHTED_MEAN) {
 299                             $outcome_item->aggregationcoef = 1;
 300                         } else {
 301                             $outcome_item->aggregationcoef = 0;
 302                         }
 303                         $outcome_item->update();
 304                     }
 305                 }
 306             }
 307         }
 308     }
 309
 310     if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_ADVANCED_GRADING, false)
 311             and has_capability('moodle/grade:managegradingforms', $modcontext)) {
 312         require_once($CFG->dirroot.'/grade/grading/lib.php');
 313         $gradingman = get_grading_manager($modcontext, 'mod_'.$moduleinfo->modulename);
 314         $showgradingmanagement = false;
 315         foreach ($gradingman->get_available_areas() as $areaname => $aretitle) {
 316             $formfield = 'advancedgradingmethod_'.$areaname;
 317             if (isset($moduleinfo->{$formfield})) {
 318                 $gradingman->set_area($areaname);
 319                 $methodchanged = $gradingman->set_active_method($moduleinfo->{$formfield});
 320                 if (empty($moduleinfo->{$formfield})) {
 321                     // Going back to the simple direct grading is not a reason to open the management screen.
 322                     $methodchanged = false;
 323                 }
 324                 $showgradingmanagement = $showgradingmanagement || $methodchanged;
 325             }
 326         }
 327         // Update grading management information.
 328         $moduleinfo->gradingman = $gradingman;
 329         $moduleinfo->showgradingmanagement = $showgradingmanagement;
 330     }
 331
 332     rebuild_course_cache($course->id, true);
 333     if ($hasgrades) {
 334         grade_regrade_final_grades($course->id);
 335     }
 336     require_once($CFG->libdir.'/plagiarismlib.php');
 337     plagiarism_save_form_elements($moduleinfo);
 338
 339     return $moduleinfo;
 340 }
 341
 342
 343 /**
 344  * Set module info default values for the unset module attributs.
 345  *
 346  * @param object $moduleinfo the current known data of the module
 347  * @return object the completed module info
 348  */
 349 function set_moduleinfo_defaults($moduleinfo) {
 350
 351     if (empty($moduleinfo->coursemodule)) {
 352         // Add.
 353         $cm = null;
 354         $moduleinfo->instance     = '';
 355         $moduleinfo->coursemodule = '';
 356     } else {
 357         // Update.
 358         $cm = get_coursemodule_from_id('', $moduleinfo->coursemodule, 0, false, MUST_EXIST);
 359         $moduleinfo->instance     = $cm->instance;
 360         $moduleinfo->coursemodule = $cm->id;
 361     }
 362     // For safety.
 363     $moduleinfo->modulename = clean_param($moduleinfo->modulename, PARAM_PLUGIN);
 364
 365     if (!isset($moduleinfo->groupingid)) {
 366         $moduleinfo->groupingid = 0;
 367     }
 368
 369     if (!isset($moduleinfo->name)) { // Label.
 370         $moduleinfo->name = $moduleinfo->modulename;
 371     }
 372
 373     if (!isset($moduleinfo->completion)) {
 374         $moduleinfo->completion = COMPLETION_DISABLED;
 375     }
 376     if (!isset($moduleinfo->completionview)) {
 377         $moduleinfo->completionview = COMPLETION_VIEW_NOT_REQUIRED;
 378     }
 379     if (!isset($moduleinfo->completionexpected)) {
 380         $moduleinfo->completionexpected = 0;
 381     }
 382
 383     // Convert the 'use grade' checkbox into a grade-item number: 0 if checked, null if not.
 384     if (isset($moduleinfo->completionusegrade) && $moduleinfo->completionusegrade) {
 385         $moduleinfo->completiongradeitemnumber = 0;
 386     } else {
 387         $moduleinfo->completiongradeitemnumber = null;
 388     }
 389
 390     if (!isset($moduleinfo->conditiongradegroup)) {
 391         $moduleinfo->conditiongradegroup = array();
 392     }
 393     if (!isset($moduleinfo->conditionfieldgroup)) {
 394         $moduleinfo->conditionfieldgroup = array();
 395     }
 396
 397     return $moduleinfo;
 398 }
 399
 400 /**
 401  * Check that the user can add a module. Also returns some information like the module, context and course section info.
 402  * The fucntion create the course section if it doesn't exist.
 403  *
 404  * @param object $course the course of the module
 405  * @param object $modulename the module name
 406  * @param object $section the section of the module
 407  * @return array list containing module, context, course section.
 408  * @throws moodle_exception if user is not allowed to perform the action or module is not allowed in this course
 409  */
 410 function can_add_moduleinfo($course, $modulename, $section) {
 411     global $DB;
 412
 413     $module = $DB->get_record('modules', array('name'=>$modulename), '*', MUST_EXIST);
 414
 415     $context = context_course::instance($course->id);
 416     require_capability('moodle/course:manageactivities', $context);
 417
 418     course_create_sections_if_missing($course, $section);
 419     $cw = get_fast_modinfo($course)->get_section_info($section);
 420
 421     if (!course_allowed_module($course, $module->name)) {
 422         print_error('moduledisable');
 423     }
 424
 425     return array($module, $context, $cw);
 426 }
 427
 428 /**
 429  * Check if user is allowed to update module info and returns related item/data to the module.
 430  *
 431  * @param object $cm course module
 432  * @return array - list of course module, context, module, moduleinfo, and course section.
 433  * @throws moodle_exception if user is not allowed to perform the action
 434  */
 435 function can_update_moduleinfo($cm) {
 436     global $DB;
 437
 438     // Check the $USER has the right capability.
 439     $context = context_module::instance($cm->id);
 440     require_capability('moodle/course:manageactivities', $context);
 441
 442     // Check module exists.
 443     $module = $DB->get_record('modules', array('id'=>$cm->module), '*', MUST_EXIST);
 444
 445     // Check the moduleinfo exists.
 446     $data = $DB->get_record($module->name, array('id'=>$cm->instance), '*', MUST_EXIST);
 447
 448     // Check the course section exists.
 449     $cw = $DB->get_record('course_sections', array('id'=>$cm->section), '*', MUST_EXIST);
 450
 451     return array($cm, $context, $module, $data, $cw);
 452 }
 453
 454
 455 /**
 456  * Update the module info.
 457  * This function doesn't check the user capabilities. It updates the course module and the module instance.
 458  * Then execute common action to create/update module process (trigger event, rebuild cache, save plagiarism settings...).
 459  *
 460  * @param object $cm course module
 461  * @param object $moduleinfo module info
 462  * @param object $course course of the module
 463  * @param object $mform - the mform is required by some specific module in the function MODULE_update_instance(). This is due to a hack in this function.
 464  * @return array list of course module and module info.
 465  */
 466 function update_moduleinfo($cm, $moduleinfo, $course, $mform = null) {
 467     global $DB, $CFG;
 468
 469     // Attempt to include module library before we make any changes to DB.
 470     include_modulelib($moduleinfo->modulename);
 471
 472     $moduleinfo->course = $course->id;
 473     $moduleinfo = set_moduleinfo_defaults($moduleinfo);
 474
 475     if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
 476         $moduleinfo->groupmode = $cm->groupmode; // Keep original.
 477     }
 478
 479     // Update course module first.
 480     $cm->groupmode = $moduleinfo->groupmode;
 481     if (isset($moduleinfo->groupingid)) {
 482         $cm->groupingid = $moduleinfo->groupingid;
 483     }
 484
 485     $completion = new completion_info($course);
 486     if ($completion->is_enabled() && !empty($moduleinfo->completionunlocked)) {
 487         // Update completion settings.
 488         $cm->completion                = $moduleinfo->completion;
 489         $cm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
 490         $cm->completionview            = $moduleinfo->completionview;
 491         $cm->completionexpected        = $moduleinfo->completionexpected;
 492     }
 493     if (!empty($CFG->enableavailability)) {
 494         // This code is used both when submitting the form, which uses a long
 495         // name to avoid clashes, and by unit test code which uses the real
 496         // name in the table.
 497         if (property_exists($moduleinfo, 'availabilityconditionsjson')) {
 498             if ($moduleinfo->availabilityconditionsjson !== '') {
 499                 $cm->availability = $moduleinfo->availabilityconditionsjson;
 500             } else {
 501                 $cm->availability = null;
 502             }
 503         } else if (property_exists($moduleinfo, 'availability')) {
 504             $cm->availability = $moduleinfo->availability;
 505         }
 506         // If there is any availability data, verify it.
 507         if ($cm->availability) {
 508             $tree = new \core_availability\tree(json_decode($cm->availability));
 509             // Save time and database space by setting null if the only data
 510             // is an empty tree.
 511             if ($tree->is_empty()) {
 512                 $cm->availability = null;
 513             }
 514         }
 515     }
 516     if (isset($moduleinfo->showdescription)) {
 517         $cm->showdescription = $moduleinfo->showdescription;
 518     } else {
 519         $cm->showdescription = 0;
 520     }
 521
 522     $DB->update_record('course_modules', $cm);
 523
 524     $modcontext = context_module::instance($moduleinfo->coursemodule);
 525
 526     // Update embedded links and save files.
 527     if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true)) {
 528         $moduleinfo->intro = file_save_draft_area_files($moduleinfo->introeditor['itemid'], $modcontext->id,
 529                                                       'mod_'.$moduleinfo->modulename, 'intro', 0,
 530                                                       array('subdirs'=>true), $moduleinfo->introeditor['text']);
 531         $moduleinfo->introformat = $moduleinfo->introeditor['format'];
 532         unset($moduleinfo->introeditor);
 533     }
 534     $updateinstancefunction = $moduleinfo->modulename."_update_instance";
 535     if (!$updateinstancefunction($moduleinfo, $mform)) {
 536         print_error('cannotupdatemod', '', course_get_url($course, $cw->section), $moduleinfo->modulename);
 537     }
 538
 539     // Make sure visibility is set correctly (in particular in calendar).
 540     if (has_capability('moodle/course:activityvisibility', $modcontext)) {
 541         set_coursemodule_visible($moduleinfo->coursemodule, $moduleinfo->visible);
 542     }
 543
 544     if (isset($moduleinfo->cmidnumber)) { // Label.
 545         // Set cm idnumber - uniqueness is already verified by form validation.
 546         set_coursemodule_idnumber($moduleinfo->coursemodule, $moduleinfo->cmidnumber);
 547     }
 548
 549     // Now that module is fully updated, also update completion data if required.
 550     // (this will wipe all user completion data and recalculate it)
 551     if ($completion->is_enabled() && !empty($moduleinfo->completionunlocked)) {
 552         $completion->reset_all_state($cm);
 553     }
 554     $cm->name = $moduleinfo->name;
 555     \core\event\course_module_updated::create_from_cm($cm, $modcontext)->trigger();
 556
 557     $moduleinfo = edit_module_post_actions($moduleinfo, $course);
 558
 559     return array($cm, $moduleinfo);
 560 }
 561
 562 /**
 563  * Include once the module lib file.
 564  *
 565  * @param string $modulename module name of the lib to include
 566  * @throws moodle_exception if lib.php file for the module does not exist
 567  */
 568 function include_modulelib($modulename) {
 569     global $CFG;
 570     $modlib = "$CFG->dirroot/mod/$modulename/lib.php";
 571     if (file_exists($modlib)) {
 572         include_once($modlib);
 573     } else {
 574         throw new moodle_exception('modulemissingcode', '', '', $modlib);
 575     }
 576 }
 577