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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 * Base class for conditional availability information (for module or section). 19 * 20 * @package core_availability 21 * @copyright 2014 The Open University 22 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 23 */ 24 25 namespace core_availability; 26 27 defined('MOODLE_INTERNAL') || die(); 28 29 /** 30 * Base class for conditional availability information (for module or section). 31 * 32 * @package core_availability 33 * @copyright 2014 The Open University 34 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 35 */ 36 abstract class info { 37 /** @var \stdClass Course */ 38 protected $course; 39 40 /** @var \course_modinfo Modinfo (available only during some functions) */ 41 protected $modinfo = null; 42 43 /** @var bool Visibility flag (eye icon) */ 44 protected $visible; 45 46 /** @var string Availability data as JSON string */ 47 protected $availability; 48 49 /** @var tree Availability configuration, decoded from JSON; null if unset */ 50 protected $availabilitytree; 51 52 /** @var array|null Array of information about current restore if any */ 53 protected static $restoreinfo = null; 54 55 /** 56 * Constructs with item details. 57 * 58 * @param \stdClass $course Course object 59 * @param int $visible Value of visible flag (eye icon) 60 * @param string $availability Availability definition (JSON format) or null 61 * @throws \coding_exception If data is not valid JSON format 62 */ 63 public function __construct($course, $visible, $availability) { 64 // Set basic values. 65 $this->course = $course; 66 $this->visible = (bool)$visible; 67 $this->availability = $availability; 68 } 69 70 /** 71 * Obtains the course associated with this availability information. 72 * 73 * @return \stdClass Moodle course object 74 */ 75 public function get_course() { 76 return $this->course; 77 } 78 79 /** 80 * Gets context used for checking capabilities for this item. 81 * 82 * @return \context Context for this item 83 */ 84 public abstract function get_context(); 85 86 /** 87 * Obtains the modinfo associated with this availability information. 88 * 89 * Note: This field is available ONLY for use by conditions when calculating 90 * availability or information. 91 * 92 * @return \course_modinfo Modinfo 93 * @throws \coding_exception If called at incorrect times 94 */ 95 public function get_modinfo() { 96 if (!$this->modinfo) { 97 throw new \coding_exception( 98 'info::get_modinfo available only during condition checking'); 99 } 100 return $this->modinfo; 101 } 102 103 /** 104 * Gets the availability tree, decoding it if not already done. 105 * 106 * @return tree Availability tree 107 */ 108 public function get_availability_tree() { 109 if (is_null($this->availabilitytree)) { 110 if (is_null($this->availability)) { 111 throw new \coding_exception( 112 'Cannot call get_availability_tree with null availability'); 113 } 114 $this->availabilitytree = $this->decode_availability($this->availability, true); 115 } 116 return $this->availabilitytree; 117 } 118 119 /** 120 * Decodes availability data from JSON format. 121 * 122 * This function also validates the retrieved data as follows: 123 * 1. Data that does not meet the API-defined structure causes a 124 * coding_exception (this should be impossible unless there is 125 * a system bug or somebody manually hacks the database). 126 * 2. Data that meets the structure but cannot be implemented (e.g. 127 * reference to missing plugin or to module that doesn't exist) is 128 * either silently discarded (if $lax is true) or causes a 129 * coding_exception (if $lax is false). 130 * 131 * @param string $availability Availability string in JSON format 132 * @param boolean $lax If true, throw exceptions only for invalid structure 133 * @return tree Availability tree 134 * @throws \coding_exception If data is not valid JSON format 135 */ 136 protected function decode_availability($availability, $lax) { 137 // Decode JSON data. 138 $structure = json_decode($availability); 139 if (is_null($structure)) { 140 throw new \coding_exception('Invalid availability text', $availability); 141 } 142 143 // Recursively decode tree. 144 return new tree($structure, $lax); 145 } 146 147 /** 148 * Determines whether this particular item is currently available 149 * according to the availability criteria. 150 * 151 * - This does not include the 'visible' setting (i.e. this might return 152 * true even if visible is false); visible is handled independently. 153 * - This does not take account of the viewhiddenactivities capability. 154 * That should apply later. 155 * 156 * Depending on options selected, a description of the restrictions which 157 * mean the student can't view it (in HTML format) may be stored in 158 * $information. If there is nothing in $information and this function 159 * returns false, then the activity should not be displayed at all. 160 * 161 * This function displays debugging() messages if the availability 162 * information is invalid. 163 * 164 * @param string $information String describing restrictions in HTML format 165 * @param bool $grabthelot Performance hint: if true, caches information 166 * required for all course-modules, to make the front page and similar 167 * pages work more quickly (works only for current user) 168 * @param int $userid If set, specifies a different user ID to check availability for 169 * @param \course_modinfo $modinfo Usually leave as null for default. Specify when 170 * calling recursively from inside get_fast_modinfo() 171 * @return bool True if this item is available to the user, false otherwise 172 */ 173 public function is_available(&$information, $grabthelot = false, $userid = 0, 174 \course_modinfo $modinfo = null) { 175 global $USER; 176 177 // Default to no information. 178 $information = ''; 179 180 // Do nothing if there are no availability restrictions. 181 if (is_null($this->availability)) { 182 return true; 183 } 184 185 // Resolve optional parameters. 186 if (!$userid) { 187 $userid = $USER->id; 188 } 189 if (!$modinfo) { 190 $modinfo = get_fast_modinfo($this->course, $userid); 191 } 192 $this->modinfo = $modinfo; 193 194 // Get availability from tree. 195 try { 196 $tree = $this->get_availability_tree(); 197 $result = $tree->check_available(false, $this, $grabthelot, $userid); 198 } catch (\coding_exception $e) { 199 $this->warn_about_invalid_availability($e); 200 $this->modinfo = null; 201 return false; 202 } 203 204 // See if there are any messages. 205 if ($result->is_available()) { 206 $this->modinfo = null; 207 return true; 208 } else { 209 // If the item is marked as 'not visible' then we don't change the available 210 // flag (visible/available are treated distinctly), but we remove any 211 // availability info. If the item is hidden with the eye icon, it doesn't 212 // make sense to show 'Available from <date>' or similar, because even 213 // when that date arrives it will still not be available unless somebody 214 // toggles the eye icon. 215 if ($this->visible) { 216 $information = $tree->get_result_information($this, $result); 217 } 218 219 $this->modinfo = null; 220 return false; 221 } 222 } 223 224 /** 225 * Checks whether this activity is going to be available for all users. 226 * 227 * Normally, if there are any conditions, then it may be hidden depending 228 * on the user. However in the case of date conditions there are some 229 * conditions which will definitely not result in it being hidden for 230 * anyone. 231 * 232 * @return bool True if activity is available for all 233 */ 234 public function is_available_for_all() { 235 if (is_null($this->availability)) { 236 return true; 237 } else { 238 try { 239 return $this->get_availability_tree()->is_available_for_all(); 240 } catch (\coding_exception $e) { 241 $this->warn_about_invalid_availability($e); 242 return false; 243 } 244 } 245 } 246 247 /** 248 * Obtains a string describing all availability restrictions (even if 249 * they do not apply any more). Used to display information for staff 250 * editing the website. 251 * 252 * The modinfo parameter must be specified when it is called from inside 253 * get_fast_modinfo, to avoid infinite recursion. 254 * 255 * This function displays debugging() messages if the availability 256 * information is invalid. 257 * 258 * @param \course_modinfo $modinfo Usually leave as null for default 259 * @return string Information string (for admin) about all restrictions on 260 * this item 261 */ 262 public function get_full_information(\course_modinfo $modinfo = null) { 263 // Do nothing if there are no availability restrictions. 264 if (is_null($this->availability)) { 265 return ''; 266 } 267 268 // Resolve optional parameter. 269 if (!$modinfo) { 270 $modinfo = get_fast_modinfo($this->course); 271 } 272 $this->modinfo = $modinfo; 273 274 try { 275 $result = $this->get_availability_tree()->get_full_information($this); 276 $this->modinfo = null; 277 return $result; 278 } catch (\coding_exception $e) { 279 $this->warn_about_invalid_availability($e); 280 return false; 281 } 282 } 283 284 /** 285 * In some places we catch coding_exception because if a bug happens, it 286 * would be fatal for the course page GUI; instead we just show a developer 287 * debug message. 288 * 289 * @param \coding_exception $e Exception that occurred 290 */ 291 protected function warn_about_invalid_availability(\coding_exception $e) { 292 $name = $this->get_thing_name(); 293 // If it occurs while building modinfo based on somebody calling $cm->name, 294 // we can't get $cm->name, and this line will cause a warning. 295 $htmlname = @$this->format_info($name, $this->course); 296 if ($htmlname === '') { 297 // So instead use the numbers (cmid) from the tag. 298 $htmlname = preg_replace('~[^0-9]~', '', $name); 299 } 300 $info = 'Error processing availability data for ‘' . $htmlname 301 . '’: ' . s($e->a); 302 debugging($info, DEBUG_DEVELOPER); 303 } 304 305 /** 306 * Called during restore (near end of restore). Updates any necessary ids 307 * and writes the updated tree to the database. May output warnings if 308 * necessary (e.g. if a course-module cannot be found after restore). 309 * 310 * @param string $restoreid Restore identifier 311 * @param int $courseid Target course id 312 * @param \base_logger $logger Logger for any warnings 313 * @param int $dateoffset Date offset to be added to any dates (0 = none) 314 */ 315 public function update_after_restore($restoreid, $courseid, \base_logger $logger, $dateoffset) { 316 $tree = $this->get_availability_tree(); 317 // Set static data for use by get_restore_date_offset function. 318 self::$restoreinfo = array('restoreid' => $restoreid, 'dateoffset' => $dateoffset); 319 $changed = $tree->update_after_restore($restoreid, $courseid, $logger, 320 $this->get_thing_name()); 321 if ($changed) { 322 // Save modified data. 323 $structure = $tree->save(); 324 $this->set_in_database(json_encode($structure)); 325 } 326 } 327 328 /** 329 * Gets the date offset (amount by which any date values should be 330 * adjusted) for the current restore. 331 * 332 * @param string $restoreid Restore identifier 333 * @return int Date offset (0 if none) 334 * @throws coding_exception If not in a restore (or not in that restore) 335 */ 336 public static function get_restore_date_offset($restoreid) { 337 if (!self::$restoreinfo) { 338 throw new coding_exception('Only valid during restore'); 339 } 340 if (self::$restoreinfo['restoreid'] !== $restoreid) { 341 throw new coding_exception('Data not available for that restore id'); 342 } 343 return self::$restoreinfo['dateoffset']; 344 } 345 346 /** 347 * Obtains the name of the item (cm_info or section_info, at present) that 348 * this is controlling availability of. Name should be formatted ready 349 * for on-screen display. 350 * 351 * @return string Name of item 352 */ 353 protected abstract function get_thing_name(); 354 355 /** 356 * Stores an updated availability tree JSON structure into the relevant 357 * database table. 358 * 359 * @param string $availabilty New JSON value 360 */ 361 protected abstract function set_in_database($availabilty); 362 363 /** 364 * In rare cases the system may want to change all references to one ID 365 * (e.g. one course-module ID) to another one, within a course. This 366 * function does that for the conditional availability data for all 367 * modules and sections on the course. 368 * 369 * @param int|\stdClass $courseorid Course id or object 370 * @param string $table Table name e.g. 'course_modules' 371 * @param int $oldid Previous ID 372 * @param int $newid New ID 373 * @return bool True if anything changed, otherwise false 374 */ 375 public static function update_dependency_id_across_course( 376 $courseorid, $table, $oldid, $newid) { 377 global $DB; 378 $transaction = $DB->start_delegated_transaction(); 379 $modinfo = get_fast_modinfo($courseorid); 380 $anychanged = false; 381 foreach ($modinfo->get_cms() as $cm) { 382 $info = new info_module($cm); 383 $changed = $info->update_dependency_id($table, $oldid, $newid); 384 $anychanged = $anychanged || $changed; 385 } 386 foreach ($modinfo->get_section_info_all() as $section) { 387 $info = new info_section($section); 388 $changed = $info->update_dependency_id($table, $oldid, $newid); 389 $anychanged = $anychanged || $changed; 390 } 391 $transaction->allow_commit(); 392 if ($anychanged) { 393 get_fast_modinfo($courseorid, 0, true); 394 } 395 return $anychanged; 396 } 397 398 /** 399 * Called on a single item. If necessary, updates availability data where 400 * it has a dependency on an item with a particular id. 401 * 402 * @param string $table Table name e.g. 'course_modules' 403 * @param int $oldid Previous ID 404 * @param int $newid New ID 405 * @return bool True if it changed, otherwise false 406 */ 407 protected function update_dependency_id($table, $oldid, $newid) { 408 // Do nothing if there are no availability restrictions. 409 if (is_null($this->availability)) { 410 return false; 411 } 412 // Pass requirement on to tree object. 413 $tree = $this->get_availability_tree(); 414 $changed = $tree->update_dependency_id($table, $oldid, $newid); 415 if ($changed) { 416 // Save modified data. 417 $structure = $tree->save(); 418 $this->set_in_database(json_encode($structure)); 419 } 420 return $changed; 421 } 422 423 /** 424 * Converts legacy data from fields (if provided) into the new availability 425 * syntax. 426 * 427 * Supported fields: availablefrom, availableuntil, showavailability 428 * (and groupingid for sections). 429 * 430 * It also supports the groupmembersonly field for modules. This part was 431 * optional in 2.7 but now always runs (because groupmembersonly has been 432 * removed). 433 * 434 * @param \stdClass $rec Object possibly containing legacy fields 435 * @param bool $section True if this is a section 436 * @param bool $modgroupmembersonlyignored Ignored option, previously used 437 * @return string|null New availability value or null if none 438 */ 439 public static function convert_legacy_fields($rec, $section, $modgroupmembersonlyignored = false) { 440 // Do nothing if the fields are not set. 441 if (empty($rec->availablefrom) && empty($rec->availableuntil) && 442 (empty($rec->groupmembersonly)) && 443 (!$section || empty($rec->groupingid))) { 444 return null; 445 } 446 447 // Handle legacy availability data. 448 $conditions = array(); 449 $shows = array(); 450 451 // Groupmembersonly condition (if enabled) for modules, groupingid for 452 // sections. 453 if (!empty($rec->groupmembersonly) || 454 (!empty($rec->groupingid) && $section)) { 455 if (!empty($rec->groupingid)) { 456 $conditions[] = '{"type":"grouping"' . 457 ($rec->groupingid ? ',"id":' . $rec->groupingid : '') . '}'; 458 } else { 459 // No grouping specified, so allow any group. 460 $conditions[] = '{"type":"group"}'; 461 } 462 // Group members only condition was not displayed to students. 463 $shows[] = 'false'; 464 } 465 466 // Date conditions. 467 if (!empty($rec->availablefrom)) { 468 $conditions[] = '{"type":"date","d":">=","t":' . $rec->availablefrom . '}'; 469 $shows[] = !empty($rec->showavailability) ? 'true' : 'false'; 470 } 471 if (!empty($rec->availableuntil)) { 472 $conditions[] = '{"type":"date","d":"<","t":' . $rec->availableuntil . '}'; 473 // Until dates never showed to students. 474 $shows[] = 'false'; 475 } 476 477 // If there are some conditions, return them. 478 if ($conditions) { 479 return '{"op":"&","showc":[' . implode(',', $shows) . '],' . 480 '"c":[' . implode(',', $conditions) . ']}'; 481 } else { 482 return null; 483 } 484 } 485 486 /** 487 * Adds a condition from the legacy availability condition. 488 * 489 * (For use during restore only.) 490 * 491 * This function assumes that the activity either has no conditions, or 492 * that it has an AND tree with one or more conditions. 493 * 494 * @param string|null $availability Current availability conditions 495 * @param \stdClass $rec Object containing information from old table 496 * @param bool $show True if 'show' option should be enabled 497 * @return string New availability conditions 498 */ 499 public static function add_legacy_availability_condition($availability, $rec, $show) { 500 if (!empty($rec->sourcecmid)) { 501 // Completion condition. 502 $condition = '{"type":"completion","cm":' . $rec->sourcecmid . 503 ',"e":' . $rec->requiredcompletion . '}'; 504 } else { 505 // Grade condition. 506 $minmax = ''; 507 if (!empty($rec->grademin)) { 508 $minmax .= ',"min":' . sprintf('%.5f', $rec->grademin); 509 } 510 if (!empty($rec->grademax)) { 511 $minmax .= ',"max":' . sprintf('%.5f', $rec->grademax); 512 } 513 $condition = '{"type":"grade","id":' . $rec->gradeitemid . $minmax . '}'; 514 } 515 516 return self::add_legacy_condition($availability, $condition, $show); 517 } 518 519 /** 520 * Adds a condition from the legacy availability field condition. 521 * 522 * (For use during restore only.) 523 * 524 * This function assumes that the activity either has no conditions, or 525 * that it has an AND tree with one or more conditions. 526 * 527 * @param string|null $availability Current availability conditions 528 * @param \stdClass $rec Object containing information from old table 529 * @param bool $show True if 'show' option should be enabled 530 * @return string New availability conditions 531 */ 532 public static function add_legacy_availability_field_condition($availability, $rec, $show) { 533 if (isset($rec->userfield)) { 534 // Standard field. 535 $fieldbit = ',"sf":' . json_encode($rec->userfield); 536 } else { 537 // Custom field. 538 $fieldbit = ',"cf":' . json_encode($rec->shortname); 539 } 540 // Value is not included for certain operators. 541 switch($rec->operator) { 542 case 'isempty': 543 case 'isnotempty': 544 $valuebit = ''; 545 break; 546 547 default: 548 $valuebit = ',"v":' . json_encode($rec->value); 549 break; 550 } 551 $condition = '{"type":"profile","op":"' . $rec->operator . '"' . 552 $fieldbit . $valuebit . '}'; 553 554 return self::add_legacy_condition($availability, $condition, $show); 555 } 556 557 /** 558 * Adds a condition to an AND group. 559 * 560 * (For use during restore only.) 561 * 562 * This function assumes that the activity either has no conditions, or 563 * that it has only conditions added by this function. 564 * 565 * @param string|null $availability Current availability conditions 566 * @param string $condition Condition text '{...}' 567 * @param bool $show True if 'show' option should be enabled 568 * @return string New availability conditions 569 */ 570 protected static function add_legacy_condition($availability, $condition, $show) { 571 $showtext = ($show ? 'true' : 'false'); 572 if (is_null($availability)) { 573 $availability = '{"op":"&","showc":[' . $showtext . 574 '],"c":[' . $condition . ']}'; 575 } else { 576 $matches = array(); 577 if (!preg_match('~^({"op":"&","showc":\[(?:true|false)(?:,(?:true|false))*)' . 578 '(\],"c":\[.*)(\]})$~', $availability, $matches)) { 579 throw new \coding_exception('Unexpected availability value'); 580 } 581 $availability = $matches[1] . ',' . $showtext . $matches[2] . 582 ',' . $condition . $matches[3]; 583 } 584 return $availability; 585 } 586 587 /** 588 * Tests against a user list. Users who cannot access the activity due to 589 * availability restrictions will be removed from the list. 590 * 591 * Note this only includes availability restrictions (those handled within 592 * this API) and not other ways of restricting access. 593 * 594 * This test ONLY includes conditions which are marked as being applied to 595 * user lists. For example, group conditions are included but date 596 * conditions are not included. 597 * 598 * The function operates reasonably efficiently i.e. should not do per-user 599 * database queries. It is however likely to be fairly slow. 600 * 601 * @param array $users Array of userid => object 602 * @return array Filtered version of input array 603 */ 604 public function filter_user_list(array $users) { 605 global $CFG; 606 if (is_null($this->availability) || !$CFG->enableavailability) { 607 return $users; 608 } 609 $tree = $this->get_availability_tree(); 610 $checker = new capability_checker($this->get_context()); 611 $this->modinfo = get_fast_modinfo($this->get_course()); 612 $result = $tree->filter_user_list($users, false, $this, $checker); 613 $this->modinfo = null; 614 return $result; 615 } 616 617 /** 618 * Obtains SQL that returns a list of enrolled users that has been filtered 619 * by the conditions applied in the availability API, similar to calling 620 * get_enrolled_users and then filter_user_list. As for filter_user_list, 621 * this ONLY filteres out users with conditions that are marked as applying 622 * to user lists. For example, group conditions are included but date 623 * conditions are not included. 624 * 625 * The returned SQL is a query that returns a list of user IDs. It does not 626 * include brackets, so you neeed to add these to make it into a subquery. 627 * You would normally use it in an SQL phrase like "WHERE u.id IN ($sql)". 628 * 629 * The function returns an array with '' and an empty array, if there are 630 * no restrictions on users from these conditions. 631 * 632 * The SQL will be complex and may be slow. It uses named parameters (sorry, 633 * I know they are annoying, but it was unavoidable here). 634 * 635 * @param bool $onlyactive True if including only active enrolments 636 * @return array Array of SQL code (may be empty) and params 637 */ 638 public function get_user_list_sql($onlyactive) { 639 global $CFG; 640 if (is_null($this->availability) || !$CFG->enableavailability) { 641 return array('', array()); 642 } 643 $tree = $this->get_availability_tree(); 644 return $tree->get_user_list_sql(false, $this, $onlyactive); 645 } 646 647 /** 648 * Formats the $cm->availableinfo string for display. This includes 649 * filling in the names of any course-modules that might be mentioned. 650 * Should be called immediately prior to display, or at least somewhere 651 * that we can guarantee does not happen from within building the modinfo 652 * object. 653 * 654 * @param string $info Info string 655 * @param int|\stdClass $courseorid 656 * @return string Correctly formatted info string 657 */ 658 public static function format_info($info, $courseorid) { 659 // Don't waste time if there are no special tags. 660 if (strpos($info, '<AVAILABILITY_') === false) { 661 return $info; 662 } 663 664 // Handle CMNAME tags. 665 $modinfo = get_fast_modinfo($courseorid); 666 $context = \context_course::instance($modinfo->courseid); 667 $info = preg_replace_callback('~<AVAILABILITY_CMNAME_([0-9]+)/>~', 668 function($matches) use($modinfo, $context) { 669 $cm = $modinfo->get_cm($matches[1]); 670 if ($cm->has_view() and $cm->uservisible) { 671 // Help student by providing a link to the module which is preventing availability. 672 return \html_writer::link($cm->url, format_string($cm->name, true, array('context' => $context))); 673 } else { 674 return format_string($cm->name, true, array('context' => $context)); 675 } 676 }, $info); 677 678 return $info; 679 } 680 681 /** 682 * Used in course/lib.php because we need to disable the completion tickbox 683 * JS (using the non-JS version instead, which causes a page reload) if a 684 * completion tickbox value may affect a conditional activity. 685 * 686 * @param \stdClass $course Moodle course object 687 * @param int $cmid Course-module id 688 * @return bool True if this is used in a condition, false otherwise 689 */ 690 public static function completion_value_used($course, $cmid) { 691 // Access all plugins. Normally only the completion plugin is going 692 // to affect this value, but it's potentially possible that some other 693 // plugin could also rely on the completion plugin. 694 $pluginmanager = \core_plugin_manager::instance(); 695 $enabled = $pluginmanager->get_enabled_plugins('availability'); 696 $componentparams = new \stdClass(); 697 foreach ($enabled as $plugin => $info) { 698 // Use the static method. 699 $class = '\availability_' . $plugin . '\condition'; 700 if ($class::completion_value_used($course, $cmid)) { 701 return true; 702 } 703 } 704 return false; 705 } 706 }
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| Generated: Fri Nov 28 20:29:05 2014 | Cross-referenced by PHPXref 0.7.1 |