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See Release Notes
Long Term Support Release
- Bug fixes for general core bugs in 3.9.x will end* 10 May 2021 (12 months).
- Bug fixes for security issues in 3.9.x will end* 8 May 2023 (36 months).
- PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
/cache/classes/ -> helper.php (source)
Differences Between: [Versions 39 and 310] [Versions 39 and 311] [Versions 39 and 400] [Versions 39 and 401] [Versions 39 and 402] [Versions 39 and 403]
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 * Cache helper class 19 * 20 * This file is part of Moodle's cache API, affectionately called MUC. 21 * It contains the components that are requried in order to use caching. 22 * 23 * @package core 24 * @category cache 25 * @copyright 2012 Sam Hemelryk 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 cache helper class. 33 * 34 * The cache helper class provides common functionality to the cache API and is useful to developers within to interact with 35 * the cache API in a general way. 36 * 37 * @package core 38 * @category cache 39 * @copyright 2012 Sam Hemelryk 40 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 41 */ 42 class cache_helper { 43 44 /** 45 * Statistics gathered by the cache API during its operation will be used here. 46 * @static 47 * @var array 48 */ 49 protected static $stats = array(); 50 51 /** 52 * The instance of the cache helper. 53 * @var cache_helper 54 */ 55 protected static $instance; 56 57 /** 58 * The site identifier used by the cache. 59 * Set the first time get_site_identifier is called. 60 * @var string 61 */ 62 protected static $siteidentifier = null; 63 64 /** 65 * Returns true if the cache API can be initialised before Moodle has finished initialising itself. 66 * 67 * This check is essential when trying to cache the likes of configuration information. It checks to make sure that the cache 68 * configuration file has been created which allows use to set up caching when ever is required. 69 * 70 * @return bool 71 */ 72 public static function ready_for_early_init() { 73 return cache_config::config_file_exists(); 74 } 75 76 /** 77 * Returns an instance of the cache_helper. 78 * 79 * This is designed for internal use only and acts as a static store. 80 * @staticvar null $instance 81 * @return cache_helper 82 */ 83 protected static function instance() { 84 if (is_null(self::$instance)) { 85 self::$instance = new cache_helper(); 86 } 87 return self::$instance; 88 } 89 90 /** 91 * Constructs an instance of the cache_helper class. Again for internal use only. 92 */ 93 protected function __construct() { 94 // Nothing to do here, just making sure you can't get an instance of this. 95 } 96 97 /** 98 * Used as a data store for initialised definitions. 99 * @var array 100 */ 101 protected $definitions = array(); 102 103 /** 104 * Used as a data store for initialised cache stores 105 * We use this because we want to avoid establishing multiple instances of a single store. 106 * @var array 107 */ 108 protected $stores = array(); 109 110 /** 111 * Returns the class for use as a cache loader for the given mode. 112 * 113 * @param int $mode One of cache_store::MODE_ 114 * @return string 115 * @throws coding_exception 116 */ 117 public static function get_class_for_mode($mode) { 118 switch ($mode) { 119 case cache_store::MODE_APPLICATION : 120 return 'cache_application'; 121 case cache_store::MODE_REQUEST : 122 return 'cache_request'; 123 case cache_store::MODE_SESSION : 124 return 'cache_session'; 125 } 126 throw new coding_exception('Unknown cache mode passed. Must be one of cache_store::MODE_*'); 127 } 128 129 /** 130 * Returns the cache stores to be used with the given definition. 131 * @param cache_definition $definition 132 * @return array 133 */ 134 public static function get_cache_stores(cache_definition $definition) { 135 $instance = cache_config::instance(); 136 $stores = $instance->get_stores_for_definition($definition); 137 $stores = self::initialise_cachestore_instances($stores, $definition); 138 return $stores; 139 } 140 141 /** 142 * Internal function for initialising an array of stores against a given cache definition. 143 * 144 * @param array $stores 145 * @param cache_definition $definition 146 * @return cache_store[] 147 */ 148 protected static function initialise_cachestore_instances(array $stores, cache_definition $definition) { 149 $return = array(); 150 $factory = cache_factory::instance(); 151 foreach ($stores as $name => $details) { 152 $store = $factory->create_store_from_config($name, $details, $definition); 153 if ($store !== false) { 154 $return[] = $store; 155 } 156 } 157 return $return; 158 } 159 160 /** 161 * Returns a cache_lock instance suitable for use with the store. 162 * 163 * @param cache_store $store 164 * @return cache_lock_interface 165 */ 166 public static function get_cachelock_for_store(cache_store $store) { 167 $instance = cache_config::instance(); 168 $lockconf = $instance->get_lock_for_store($store->my_name()); 169 $factory = cache_factory::instance(); 170 return $factory->create_lock_instance($lockconf); 171 } 172 173 /** 174 * Returns an array of plugins without using core methods. 175 * 176 * This function explicitly does NOT use core functions as it will in some circumstances be called before Moodle has 177 * finished initialising. This happens when loading configuration for instance. 178 * 179 * @return string 180 */ 181 public static function early_get_cache_plugins() { 182 global $CFG; 183 $result = array(); 184 $ignored = array('CVS', '_vti_cnf', 'simpletest', 'db', 'yui', 'tests'); 185 $fulldir = $CFG->dirroot.'/cache/stores'; 186 $items = new DirectoryIterator($fulldir); 187 foreach ($items as $item) { 188 if ($item->isDot() or !$item->isDir()) { 189 continue; 190 } 191 $pluginname = $item->getFilename(); 192 if (in_array($pluginname, $ignored)) { 193 continue; 194 } 195 if (!is_valid_plugin_name($pluginname)) { 196 // Better ignore plugins with problematic names here. 197 continue; 198 } 199 $result[$pluginname] = $fulldir.'/'.$pluginname; 200 unset($item); 201 } 202 unset($items); 203 return $result; 204 } 205 206 /** 207 * Invalidates a given set of keys from a given definition. 208 * 209 * @todo Invalidating by definition should also add to the event cache so that sessions can be invalidated (when required). 210 * 211 * @param string $component 212 * @param string $area 213 * @param array $identifiers 214 * @param array $keys 215 * @return boolean 216 */ 217 public static function invalidate_by_definition($component, $area, array $identifiers = array(), $keys = array()) { 218 $cache = cache::make($component, $area, $identifiers); 219 if (is_array($keys)) { 220 $cache->delete_many($keys); 221 } else if (is_scalar($keys)) { 222 $cache->delete($keys); 223 } else { 224 throw new coding_exception('cache_helper::invalidate_by_definition only accepts $keys as array, or scalar.'); 225 } 226 return true; 227 } 228 229 /** 230 * Invalidates a given set of keys by means of an event. 231 * 232 * Events cannot determine what identifiers might need to be cleared. Event based purge and invalidation 233 * are only supported on caches without identifiers. 234 * 235 * @param string $event 236 * @param array $keys 237 */ 238 public static function invalidate_by_event($event, array $keys) { 239 $instance = cache_config::instance(); 240 $invalidationeventset = false; 241 $factory = cache_factory::instance(); 242 $inuse = $factory->get_caches_in_use(); 243 $purgetoken = null; 244 foreach ($instance->get_definitions() as $name => $definitionarr) { 245 $definition = cache_definition::load($name, $definitionarr); 246 if ($definition->invalidates_on_event($event)) { 247 // First up check if there is a cache loader for this definition already. 248 // If there is we need to invalidate the keys from there. 249 $definitionkey = $definition->get_component().'/'.$definition->get_area(); 250 if (isset($inuse[$definitionkey])) { 251 $inuse[$definitionkey]->delete_many($keys); 252 } 253 254 // We should only log events for application and session caches. 255 // Request caches shouldn't have events as all data is lost at the end of the request. 256 // Events should only be logged once of course and likely several definitions are watching so we 257 // track its logging with $invalidationeventset. 258 $logevent = ($invalidationeventset === false && $definition->get_mode() !== cache_store::MODE_REQUEST); 259 260 if ($logevent) { 261 // Get the event invalidation cache. 262 $cache = cache::make('core', 'eventinvalidation'); 263 // Get any existing invalidated keys for this cache. 264 $data = $cache->get($event); 265 if ($data === false) { 266 // There are none. 267 $data = array(); 268 } 269 // Add our keys to them with the current cache timestamp. 270 if (null === $purgetoken) { 271 $purgetoken = cache::get_purge_token(true); 272 } 273 foreach ($keys as $key) { 274 $data[$key] = $purgetoken; 275 } 276 // Set that data back to the cache. 277 $cache->set($event, $data); 278 // This only needs to occur once. 279 $invalidationeventset = true; 280 } 281 } 282 } 283 } 284 285 /** 286 * Purges the cache for a specific definition. 287 * 288 * @param string $component 289 * @param string $area 290 * @param array $identifiers 291 * @return bool 292 */ 293 public static function purge_by_definition($component, $area, array $identifiers = array()) { 294 // Create the cache. 295 $cache = cache::make($component, $area, $identifiers); 296 // Initialise, in case of a store. 297 if ($cache instanceof cache_store) { 298 $factory = cache_factory::instance(); 299 $definition = $factory->create_definition($component, $area, null); 300 $cacheddefinition = clone $definition; 301 $cacheddefinition->set_identifiers($identifiers); 302 $cache->initialise($cacheddefinition); 303 } 304 // Purge baby, purge. 305 $cache->purge(); 306 return true; 307 } 308 309 /** 310 * Purges a cache of all information on a given event. 311 * 312 * Events cannot determine what identifiers might need to be cleared. Event based purge and invalidation 313 * are only supported on caches without identifiers. 314 * 315 * @param string $event 316 */ 317 public static function purge_by_event($event) { 318 $instance = cache_config::instance(); 319 $invalidationeventset = false; 320 $factory = cache_factory::instance(); 321 $inuse = $factory->get_caches_in_use(); 322 $purgetoken = null; 323 foreach ($instance->get_definitions() as $name => $definitionarr) { 324 $definition = cache_definition::load($name, $definitionarr); 325 if ($definition->invalidates_on_event($event)) { 326 // First up check if there is a cache loader for this definition already. 327 // If there is we need to invalidate the keys from there. 328 $definitionkey = $definition->get_component().'/'.$definition->get_area(); 329 if (isset($inuse[$definitionkey])) { 330 $inuse[$definitionkey]->purge(); 331 } else { 332 cache::make($definition->get_component(), $definition->get_area())->purge(); 333 } 334 335 // We should only log events for application and session caches. 336 // Request caches shouldn't have events as all data is lost at the end of the request. 337 // Events should only be logged once of course and likely several definitions are watching so we 338 // track its logging with $invalidationeventset. 339 $logevent = ($invalidationeventset === false && $definition->get_mode() !== cache_store::MODE_REQUEST); 340 341 // We need to flag the event in the "Event invalidation" cache if it hasn't already happened. 342 if ($logevent && $invalidationeventset === false) { 343 // Get the event invalidation cache. 344 $cache = cache::make('core', 'eventinvalidation'); 345 // Create a key to invalidate all. 346 if (null === $purgetoken) { 347 $purgetoken = cache::get_purge_token(true); 348 } 349 $data = array( 350 'purged' => $purgetoken, 351 ); 352 // Set that data back to the cache. 353 $cache->set($event, $data); 354 // This only needs to occur once. 355 $invalidationeventset = true; 356 } 357 } 358 } 359 } 360 361 /** 362 * Ensure that the stats array is ready to collect information for the given store and definition. 363 * @param string $store 364 * @param string $storeclass 365 * @param string $definition A string that identifies the definition. 366 * @param int $mode One of cache_store::MODE_*. Since 2.9. 367 */ 368 protected static function ensure_ready_for_stats($store, $storeclass, $definition, $mode = cache_store::MODE_APPLICATION) { 369 // This function is performance-sensitive, so exit as quickly as possible 370 // if we do not need to do anything. 371 if (isset(self::$stats[$definition]['stores'][$store])) { 372 return; 373 } 374 375 if (!array_key_exists($definition, self::$stats)) { 376 self::$stats[$definition] = array( 377 'mode' => $mode, 378 'stores' => array( 379 $store => array( 380 'class' => $storeclass, 381 'hits' => 0, 382 'misses' => 0, 383 'sets' => 0, 384 ) 385 ) 386 ); 387 } else if (!array_key_exists($store, self::$stats[$definition]['stores'])) { 388 self::$stats[$definition]['stores'][$store] = array( 389 'class' => $storeclass, 390 'hits' => 0, 391 'misses' => 0, 392 'sets' => 0, 393 ); 394 } 395 } 396 397 /** 398 * Returns a string to describe the definition. 399 * 400 * This method supports the definition as a string due to legacy requirements. 401 * It is backwards compatible when a string is passed but is not accurate. 402 * 403 * @since 2.9 404 * @param cache_definition|string $definition 405 * @return string 406 */ 407 protected static function get_definition_stat_id_and_mode($definition) { 408 if (!($definition instanceof cache_definition)) { 409 // All core calls to this method have been updated, this is the legacy state. 410 // We'll use application as the default as that is the most common, really this is not accurate of course but 411 // at this point we can only guess and as it only affects calls to cache stat outside of core (of which there should 412 // be none) I think that is fine. 413 debugging('Please update you cache stat calls to pass the definition rather than just its ID.', DEBUG_DEVELOPER); 414 return array((string)$definition, cache_store::MODE_APPLICATION); 415 } 416 return array($definition->get_id(), $definition->get_mode()); 417 } 418 419 /** 420 * Record a cache hit in the stats for the given store and definition. 421 * 422 * In Moodle 2.9 the $definition argument changed from accepting only a string to accepting a string or a 423 * cache_definition instance. It is preferable to pass a cache definition instance. 424 * 425 * In Moodle 3.9 the first argument changed to also accept a cache_store. 426 * 427 * @internal 428 * @param string|cache_store $store 429 * @param cache_definition $definition You used to be able to pass a string here, however that is deprecated please pass the 430 * actual cache_definition object now. 431 * @param int $hits The number of hits to record (by default 1) 432 */ 433 public static function record_cache_hit($store, $definition, $hits = 1) { 434 $storeclass = ''; 435 if ($store instanceof cache_store) { 436 $storeclass = get_class($store); 437 $store = $store->my_name(); 438 } 439 list($definitionstr, $mode) = self::get_definition_stat_id_and_mode($definition); 440 self::ensure_ready_for_stats($store, $storeclass, $definitionstr, $mode); 441 self::$stats[$definitionstr]['stores'][$store]['hits'] += $hits; 442 } 443 444 /** 445 * Record a cache miss in the stats for the given store and definition. 446 * 447 * In Moodle 2.9 the $definition argument changed from accepting only a string to accepting a string or a 448 * cache_definition instance. It is preferable to pass a cache definition instance. 449 * 450 * In Moodle 3.9 the first argument changed to also accept a cache_store. 451 * 452 * @internal 453 * @param string|cache_store $store 454 * @param cache_definition $definition You used to be able to pass a string here, however that is deprecated please pass the 455 * actual cache_definition object now. 456 * @param int $misses The number of misses to record (by default 1) 457 */ 458 public static function record_cache_miss($store, $definition, $misses = 1) { 459 $storeclass = ''; 460 if ($store instanceof cache_store) { 461 $storeclass = get_class($store); 462 $store = $store->my_name(); 463 } 464 list($definitionstr, $mode) = self::get_definition_stat_id_and_mode($definition); 465 self::ensure_ready_for_stats($store, $storeclass, $definitionstr, $mode); 466 self::$stats[$definitionstr]['stores'][$store]['misses'] += $misses; 467 } 468 469 /** 470 * Record a cache set in the stats for the given store and definition. 471 * 472 * In Moodle 2.9 the $definition argument changed from accepting only a string to accepting a string or a 473 * cache_definition instance. It is preferable to pass a cache definition instance. 474 * 475 * In Moodle 3.9 the first argument changed to also accept a cache_store. 476 * 477 * @internal 478 * @param string|cache_store $store 479 * @param cache_definition $definition You used to be able to pass a string here, however that is deprecated please pass the 480 * actual cache_definition object now. 481 * @param int $sets The number of sets to record (by default 1) 482 */ 483 public static function record_cache_set($store, $definition, $sets = 1) { 484 $storeclass = ''; 485 if ($store instanceof cache_store) { 486 $storeclass = get_class($store); 487 $store = $store->my_name(); 488 } 489 list($definitionstr, $mode) = self::get_definition_stat_id_and_mode($definition); 490 self::ensure_ready_for_stats($store, $storeclass, $definitionstr, $mode); 491 self::$stats[$definitionstr]['stores'][$store]['sets'] += $sets; 492 } 493 494 /** 495 * Return the stats collected so far. 496 * @return array 497 */ 498 public static function get_stats() { 499 return self::$stats; 500 } 501 502 /** 503 * Purge all of the cache stores of all of their data. 504 * 505 * Think twice before calling this method. It will purge **ALL** caches regardless of whether they have been used recently or 506 * anything. This will involve full setup of the cache + the purge operation. On a site using caching heavily this WILL be 507 * painful. 508 * 509 * @param bool $usewriter If set to true the cache_config_writer class is used. This class is special as it avoids 510 * it is still usable when caches have been disabled. 511 * Please use this option only if you really must. It's purpose is to allow the cache to be purged when it would be 512 * otherwise impossible. 513 */ 514 public static function purge_all($usewriter = false) { 515 $factory = cache_factory::instance(); 516 $config = $factory->create_config_instance($usewriter); 517 foreach ($config->get_all_stores() as $store) { 518 self::purge_store($store['name'], $config); 519 } 520 foreach ($factory->get_adhoc_caches_in_use() as $cache) { 521 $cache->purge(); 522 } 523 } 524 525 /** 526 * Purges a store given its name. 527 * 528 * @param string $storename 529 * @param cache_config $config 530 * @return bool 531 */ 532 public static function purge_store($storename, cache_config $config = null) { 533 if ($config === null) { 534 $config = cache_config::instance(); 535 } 536 537 $stores = $config->get_all_stores(); 538 if (!array_key_exists($storename, $stores)) { 539 // The store does not exist. 540 return false; 541 } 542 543 $store = $stores[$storename]; 544 $class = $store['class']; 545 546 547 // We check are_requirements_met although we expect is_ready is going to check as well. 548 if (!$class::are_requirements_met()) { 549 return false; 550 } 551 // Found the store: is it ready? 552 /* @var cache_store $instance */ 553 $instance = new $class($store['name'], $store['configuration']); 554 if (!$instance->is_ready()) { 555 unset($instance); 556 return false; 557 } 558 foreach ($config->get_definitions_by_store($storename) as $id => $definition) { 559 $definition = cache_definition::load($id, $definition); 560 $definitioninstance = clone($instance); 561 $definitioninstance->initialise($definition); 562 $definitioninstance->purge(); 563 unset($definitioninstance); 564 } 565 566 return true; 567 } 568 569 /** 570 * Purges all of the stores used by a definition. 571 * 572 * Unlike cache_helper::purge_by_definition this purges all of the data from the stores not 573 * just the data relating to the definition. 574 * This function is useful when you must purge a definition that requires setup but you don't 575 * want to set it up. 576 * 577 * @param string $component 578 * @param string $area 579 */ 580 public static function purge_stores_used_by_definition($component, $area) { 581 $factory = cache_factory::instance(); 582 $config = $factory->create_config_instance(); 583 $definition = $factory->create_definition($component, $area); 584 $stores = $config->get_stores_for_definition($definition); 585 foreach ($stores as $store) { 586 self::purge_store($store['name']); 587 } 588 } 589 590 /** 591 * Returns the translated name of the definition. 592 * 593 * @param cache_definition $definition 594 * @return lang_string 595 */ 596 public static function get_definition_name($definition) { 597 if ($definition instanceof cache_definition) { 598 return $definition->get_name(); 599 } 600 $identifier = 'cachedef_'.clean_param($definition['area'], PARAM_STRINGID); 601 $component = $definition['component']; 602 if ($component === 'core') { 603 $component = 'cache'; 604 } 605 return new lang_string($identifier, $component); 606 } 607 608 /** 609 * Hashes a descriptive key to make it shorter and still unique. 610 * @param string|int $key 611 * @param cache_definition $definition 612 * @return string 613 */ 614 public static function hash_key($key, cache_definition $definition) { 615 if ($definition->uses_simple_keys()) { 616 if (debugging() && preg_match('#[^a-zA-Z0-9_]#', $key)) { 617 throw new coding_exception('Cache definition '.$definition->get_id().' requires simple keys. Invalid key provided.', $key); 618 } 619 // We put the key first so that we can be sure the start of the key changes. 620 return (string)$key . '-' . $definition->generate_single_key_prefix(); 621 } 622 $key = $definition->generate_single_key_prefix() . '-' . $key; 623 return sha1($key); 624 } 625 626 /** 627 * Finds all definitions and updates them within the cache config file. 628 * 629 * @param bool $coreonly If set to true only core definitions will be updated. 630 */ 631 public static function update_definitions($coreonly = false) { 632 global $CFG; 633 // Include locallib. 634 require_once($CFG->dirroot.'/cache/locallib.php'); 635 // First update definitions 636 cache_config_writer::update_definitions($coreonly); 637 // Second reset anything we have already initialised to ensure we're all up to date. 638 cache_factory::reset(); 639 } 640 641 /** 642 * Update the site identifier stored by the cache API. 643 * 644 * @param string $siteidentifier 645 * @return string The new site identifier. 646 */ 647 public static function update_site_identifier($siteidentifier) { 648 global $CFG; 649 // Include locallib. 650 require_once($CFG->dirroot.'/cache/locallib.php'); 651 $factory = cache_factory::instance(); 652 $factory->updating_started(); 653 $config = $factory->create_config_instance(true); 654 $siteidentifier = $config->update_site_identifier($siteidentifier); 655 $factory->updating_finished(); 656 cache_factory::reset(); 657 return $siteidentifier; 658 } 659 660 /** 661 * Returns the site identifier. 662 * 663 * @return string 664 */ 665 public static function get_site_identifier() { 666 global $CFG; 667 if (!is_null(self::$siteidentifier)) { 668 return self::$siteidentifier; 669 } 670 // If site identifier hasn't been collected yet attempt to get it from the cache config. 671 $factory = cache_factory::instance(); 672 // If the factory is initialising then we don't want to try to get it from the config or we risk 673 // causing the cache to enter an infinite initialisation loop. 674 if (!$factory->is_initialising()) { 675 $config = $factory->create_config_instance(); 676 self::$siteidentifier = $config->get_site_identifier(); 677 } 678 if (is_null(self::$siteidentifier)) { 679 // If the site identifier is still null then config isn't aware of it yet. 680 // We'll see if the CFG is loaded, and if not we will just use unknown. 681 // It's very important here that we don't use get_config. We don't want an endless cache loop! 682 if (!empty($CFG->siteidentifier)) { 683 self::$siteidentifier = self::update_site_identifier($CFG->siteidentifier); 684 } else { 685 // It's not being recorded in MUC's config and the config data hasn't been loaded yet. 686 // Likely we are initialising. 687 return 'unknown'; 688 } 689 } 690 return self::$siteidentifier; 691 } 692 693 /** 694 * Returns the site version. 695 * 696 * @return string 697 */ 698 public static function get_site_version() { 699 global $CFG; 700 return (string)$CFG->version; 701 } 702 703 /** 704 * Runs cron routines for MUC. 705 */ 706 public static function cron() { 707 self::clean_old_session_data(true); 708 } 709 710 /** 711 * Cleans old session data from cache stores used for session based definitions. 712 * 713 * @param bool $output If set to true output will be given. 714 */ 715 public static function clean_old_session_data($output = false) { 716 global $CFG; 717 if ($output) { 718 mtrace('Cleaning up stale session data from cache stores.'); 719 } 720 $factory = cache_factory::instance(); 721 $config = $factory->create_config_instance(); 722 $definitions = $config->get_definitions(); 723 $purgetime = time() - $CFG->sessiontimeout; 724 foreach ($definitions as $definitionarray) { 725 // We are only interested in session caches. 726 if (!($definitionarray['mode'] & cache_store::MODE_SESSION)) { 727 continue; 728 } 729 $definition = $factory->create_definition($definitionarray['component'], $definitionarray['area']); 730 $stores = $config->get_stores_for_definition($definition); 731 // Turn them into store instances. 732 $stores = self::initialise_cachestore_instances($stores, $definition); 733 // Initialise all of the stores used for that definition. 734 foreach ($stores as $store) { 735 // If the store doesn't support searching we can skip it. 736 if (!($store instanceof cache_is_searchable)) { 737 debugging('Cache stores used for session definitions should ideally be searchable.', DEBUG_DEVELOPER); 738 continue; 739 } 740 // Get all of the keys. 741 $keys = $store->find_by_prefix(cache_session::KEY_PREFIX); 742 $todelete = array(); 743 foreach ($store->get_many($keys) as $key => $value) { 744 if (strpos($key, cache_session::KEY_PREFIX) !== 0 || !is_array($value) || !isset($value['lastaccess'])) { 745 continue; 746 } 747 if ((int)$value['lastaccess'] < $purgetime || true) { 748 $todelete[] = $key; 749 } 750 } 751 if (count($todelete)) { 752 $outcome = (int)$store->delete_many($todelete); 753 if ($output) { 754 $strdef = s($definition->get_id()); 755 $strstore = s($store->my_name()); 756 mtrace("- Removed {$outcome} old {$strdef} sessions from the '{$strstore}' cache store."); 757 } 758 } 759 } 760 } 761 } 762 763 /** 764 * Returns an array of stores that would meet the requirements for every definition. 765 * 766 * These stores would be 100% suitable to map as defaults for cache modes. 767 * 768 * @return array[] An array of stores, keys are the store names. 769 */ 770 public static function get_stores_suitable_for_mode_default() { 771 $factory = cache_factory::instance(); 772 $config = $factory->create_config_instance(); 773 $requirements = 0; 774 foreach ($config->get_definitions() as $definition) { 775 $definition = cache_definition::load($definition['component'].'/'.$definition['area'], $definition); 776 $requirements = $requirements | $definition->get_requirements_bin(); 777 } 778 $stores = array(); 779 foreach ($config->get_all_stores() as $name => $store) { 780 if (!empty($store['features']) && ($store['features'] & $requirements)) { 781 $stores[$name] = $store; 782 } 783 } 784 return $stores; 785 } 786 787 /** 788 * Returns stores suitable for use with a given definition. 789 * 790 * @param cache_definition $definition 791 * @return cache_store[] 792 */ 793 public static function get_stores_suitable_for_definition(cache_definition $definition) { 794 $factory = cache_factory::instance(); 795 $stores = array(); 796 if ($factory->is_initialising() || $factory->stores_disabled()) { 797 // No suitable stores here. 798 return $stores; 799 } else { 800 $stores = self::get_cache_stores($definition); 801 // If mappingsonly is set, having 0 stores is ok. 802 if ((count($stores) === 0) && (!$definition->is_for_mappings_only())) { 803 // No suitable stores we found for the definition. We need to come up with a sensible default. 804 // If this has happened we can be sure that the user has mapped custom stores to either the 805 // mode of the definition. The first alternative to try is the system default for the mode. 806 // e.g. the default file store instance for application definitions. 807 $config = $factory->create_config_instance(); 808 foreach ($config->get_stores($definition->get_mode()) as $name => $details) { 809 if (!empty($details['default'])) { 810 $stores[] = $factory->create_store_from_config($name, $details, $definition); 811 break; 812 } 813 } 814 } 815 } 816 return $stores; 817 } 818 819 /** 820 * Returns an array of warnings from the cache API. 821 * 822 * The warning returned here are for things like conflicting store instance configurations etc. 823 * These get shown on the admin notifications page for example. 824 * 825 * @param array|null $stores An array of stores to get warnings for, or null for all. 826 * @return string[] 827 */ 828 public static function warnings(array $stores = null) { 829 global $CFG; 830 if ($stores === null) { 831 require_once($CFG->dirroot.'/cache/locallib.php'); 832 $stores = cache_administration_helper::get_store_instance_summaries(); 833 } 834 $warnings = array(); 835 foreach ($stores as $store) { 836 if (!empty($store['warnings'])) { 837 $warnings = array_merge($warnings, $store['warnings']); 838 } 839 } 840 return $warnings; 841 } 842 }
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