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  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Cache loaders
 *
 * This file is part of Moodle's cache API, affectionately called MUC.
 * It contains the components that are required in order to use caching.
 *
 * @package    core
 * @category   cache
 * @copyright  2012 Sam Hemelryk
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

/**
 * The main cache class.
 *
 * This class if the first class that any end developer will interact with.
 * In order to create an instance of a cache that they can work with they must call one of the static make methods belonging
 * to this class.
 *
 * @package    core
 * @category   cache
 * @copyright  2012 Sam Hemelryk
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class cache implements cache_loader {

    /**
> * @var int Constant for cache entries that do not have a version number * We need a timestamp to use within the cache API. > */ * This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with > const VERSION_NONE = -1; * timing issues. > * @var int > /**
*/ protected static $now; /** * A purge token used to distinguish between multiple cache purges in the same second. * This is in the format <microtime>-<random string>. * * @var string */ protected static $purgetoken; /** * The definition used when loading this cache if there was one. * @var cache_definition */ private $definition = false; /** * The cache store that this loader will make use of. * @var cache_store */ private $store; /** * The next cache loader in the chain if there is one. * If a cache request misses for the store belonging to this loader then the loader * stored here will be checked next. * If there is a loader here then $datasource must be false. * @var cache_loader|false */ private $loader = false; /** * The data source to use if we need to load data (because if doesn't exist in the cache store). * If there is a data source here then $loader above must be false. * @var cache_data_source|false */ private $datasource = false; /** * Used to quickly check if the store supports key awareness. * This is set when the cache is initialised and is used to speed up processing. * @var bool */ private $supportskeyawareness = null; /** * Used to quickly check if the store supports ttl natively. * This is set when the cache is initialised and is used to speed up processing. * @var bool */ private $supportsnativettl = null; /** * Gets set to true if the cache is going to be using a static array for acceleration. * The array statically caches items used during the lifetime of the request. This greatly speeds up interaction * with the cache in areas where it will be repetitively hit for the same information such as with strings. * There are several other variables to control how this static acceleration array works. * @var bool */ private $staticacceleration = false; /** * The static acceleration array. * Items will be stored in this cache as they were provided. This ensure there is no unnecessary processing taking place. * @var array */ private $staticaccelerationarray = array(); /** * The number of items in the static acceleration array. Avoids count calls like you wouldn't believe. * @var int */ private $staticaccelerationcount = 0; /** * An array containing just the keys being used in the static acceleration array. * This seems redundant perhaps but is used when managing the size of the static acceleration array. * Items are added to the end of the array and the when we need to reduce the size of the cache we use the * key that is first on this array. * @var array */ private $staticaccelerationkeys = array(); /** * The maximum size of the static acceleration array. * * If set to false there is no max size. * Caches that make use of static acceleration should seriously consider setting this to something reasonably small, but * still large enough to offset repetitive calls. * * @var int|false */ private $staticaccelerationsize = false; /** * Gets set to true during initialisation if the definition is making use of a ttl. * Used to speed up processing. * @var bool */ private $hasattl = false; /** * Gets set to the class name of the store during initialisation. This is used several times in the cache class internally * and having it here helps speed up processing. * @var strubg */ protected $storetype = 'unknown'; /** * Gets set to true if we want to collect performance information about the cache API. * @var bool */ protected $perfdebug = false; /** * Determines if this loader is a sub loader, not the top of the chain. * @var bool */ protected $subloader = false; /**
> * Gets set to true if the cache writes (set|delete) must have a manual lock created first. * Creates a new cache instance for a pre-defined definition. > * @var bool * > */ * @param string $component The component for the definition > protected $requirelockingbeforewrite = false; * @param string $area The area for the definition > * @param array $identifiers Any additional identifiers that should be provided to the definition. > /** * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused. > * Gets set to true if the cache's primary store natively supports locking. * @return cache_application|cache_session|cache_store > * If it does then we use that, otherwise we need to instantiate a second store to use for locking. */ > * @var cache_store|null public static function make($component, $area, array $identifiers = array(), $unused = null) { > */ $factory = cache_factory::instance(); > protected $nativelocking = null; return $factory->create_cache_from_definition($component, $area, $identifiers); > } > /**
/** * Creates a new cache instance based upon the given params. * * @param int $mode One of cache_store::MODE_* * @param string $component The component this cache relates to. * @param string $area The area this cache relates to. * @param array $identifiers Any additional identifiers that should be provided to the definition. * @param array $options An array of options, available options are: * - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_ * - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars * - staticacceleration : If set to true the cache will hold onto data passing through it. * - staticaccelerationsize : The max size for the static acceleration array.
< * @return cache_application|cache_session|cache_store
> * @return cache_application|cache_session|cache_request
*/ public static function make_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) { $factory = cache_factory::instance(); return $factory->create_cache_from_params($mode, $component, $area, $identifiers, $options); } /** * Constructs a new cache instance. * * You should not call this method from your code, instead you should use the cache::make methods. * * This method is public so that the cache_factory is able to instantiate cache instances. * Ideally we would make this method protected and expose its construction to the factory method internally somehow. * The factory class is responsible for this in order to centralise the storage of instances once created. This way if needed * we can force a reset of the cache API (used during unit testing). * * @param cache_definition $definition The definition for the cache instance. * @param cache_store $store The store that cache should use. * @param cache_loader|cache_data_source $loader The next loader in the chain or the data source if there is one and there * are no other cache_loaders in the chain. */ public function __construct(cache_definition $definition, cache_store $store, $loader = null) { global $CFG; $this->definition = $definition; $this->store = $store; $this->storetype = get_class($store); $this->perfdebug = (!empty($CFG->perfdebug) and $CFG->perfdebug > 7); if ($loader instanceof cache_loader) { $this->set_loader($loader); } else if ($loader instanceof cache_data_source) { $this->set_data_source($loader); } $this->definition->generate_definition_hash(); $this->staticacceleration = $this->definition->use_static_acceleration(); if ($this->staticacceleration) { $this->staticaccelerationsize = $this->definition->get_static_acceleration_size(); } $this->hasattl = ($this->definition->get_ttl() > 0); } /** * Set the loader for this cache. * * @param cache_loader $loader */ protected function set_loader(cache_loader $loader): void { $this->loader = $loader; // Mark the loader as a sub (chained) loader. $this->loader->set_is_sub_loader(true); } /** * Set the data source for this cache. * * @param cache_data_source $datasource */ protected function set_data_source(cache_data_source $datasource): void { $this->datasource = $datasource; } /** * Used to inform the loader of its state as a sub loader, or as the top of the chain. * * This is important as it ensures that we do not have more than one loader keeping static acceleration data. * Subloaders need to be "pure" loaders in the sense that they are used to store and retrieve information from stores or the * next loader/data source in the chain. * Nothing fancy, nothing flash. * * @param bool $setting */ protected function set_is_sub_loader($setting = true) { if ($setting) { $this->subloader = true; // Subloaders should not keep static acceleration data. $this->staticacceleration = false; $this->staticaccelerationsize = false; } else { $this->subloader = true; $this->staticacceleration = $this->definition->use_static_acceleration(); if ($this->staticacceleration) { $this->staticaccelerationsize = $this->definition->get_static_acceleration_size(); } } } /** * Alters the identifiers that have been provided to the definition. * * This is an advanced method and should not be used unless really needed. * It allows the developer to slightly alter the definition without having to re-establish the cache. * It will cause more processing as the definition will need to clear and reprepare some of its properties. * * @param array $identifiers */ public function set_identifiers(array $identifiers) { if ($this->definition->set_identifiers($identifiers)) { // As static acceleration uses input keys and not parsed keys // it much be cleared when the identifier set is changed. $this->staticaccelerationarray = array(); if ($this->staticaccelerationsize !== false) { $this->staticaccelerationkeys = array(); $this->staticaccelerationcount = 0; } } } /** * Process any outstanding invalidation events for the cache we are registering, * * Identifiers and event invalidation are not compatible with each other at this time. * As a result the cache does not need to consider identifiers when working out what to invalidate. */ protected function handle_invalidation_events() { if (!$this->definition->has_invalidation_events()) { return; } // Each cache stores the current 'lastinvalidation' value within the cache itself. $lastinvalidation = $this->get('lastinvalidation'); if ($lastinvalidation === false) { // There is currently no value for the lastinvalidation token, therefore the token is not set, and there // can be nothing to invalidate. // Set the lastinvalidation value to the current purge token and return early. $this->set('lastinvalidation', self::get_purge_token()); return; } else if ($lastinvalidation == self::get_purge_token()) { // The current purge request has already been fully handled by this cache. return; } /* * Now that the whole cache check is complete, we check the meaning of any specific cache invalidation events. * These are stored in the core/eventinvalidation cache as an multi-dimensinoal array in the form: * [ * eventname => [ * keyname => purgetoken, * ] * ] * * The 'keyname' value is used to delete a specific key in the cache. * If the keyname is set to the special value 'purged', then the whole cache is purged instead. * * The 'purgetoken' is the token that this key was last purged. * a) If the purgetoken matches the last invalidation, then the key/cache is not purged. * b) If the purgetoken is newer than the last invalidation, then the key/cache is not purged. * c) If the purge token is older than the last invalidation, or it has a different token component, then the * cache is purged. * * Option b should not happen under normal operation, but may happen in race condition whereby a long-running * request's cache is cleared in another process during that request, and prior to that long-running request * creating the cache. In such a condition, it would be incorrect to clear that cache. */ $cache = self::make('core', 'eventinvalidation'); $events = $cache->get_many($this->definition->get_invalidation_events()); $todelete = array(); $purgeall = false; // Iterate the returned data for the events. foreach ($events as $event => $keys) { if ($keys === false) { // No data to be invalidated yet. continue; } // Look at each key and check the timestamp. foreach ($keys as $key => $purgetoken) { // If the timestamp of the event is more than or equal to the last invalidation (happened between the last // invalidation and now), then we need to invaliate the key. if (self::compare_purge_tokens($purgetoken, $lastinvalidation) > 0) { if ($key === 'purged') { $purgeall = true; break; } else { $todelete[] = $key; } } } } if ($purgeall) { $this->purge(); } else if (!empty($todelete)) { $todelete = array_unique($todelete); $this->delete_many($todelete); } // Set the time of the last invalidation. if ($purgeall || !empty($todelete)) { $this->set('lastinvalidation', self::get_purge_token(true)); } } /** * Retrieves the value for the given key from the cache. * * @param string|int $key The key for the data being requested. * It can be any structure although using a scalar string or int is recommended in the interests of performance. * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. * @param int $strictness One of IGNORE_MISSING | MUST_EXIST * @return mixed|false The data from the cache or false if the key did not exist within the cache. * @throws coding_exception */ public function get($key, $strictness = IGNORE_MISSING) {
> return $this->get_implementation($key, self::VERSION_NONE, $strictness); // 1. Get it from the static acceleration array if we can (only when it is enabled and it has already been requested/set). > } $usesstaticacceleration = $this->use_static_acceleration(); > > /** if ($usesstaticacceleration) { > * Retrieves the value and actual version for the given key, with at least the required version. $result = $this->static_acceleration_get($key); > * if ($result !== false) { > * If there is no value for the key, or there is a value but it doesn't have the required return $result; > * version, then this function will return null (or throw an exception if you set strictness } > * to MUST_EXIST). } > * > * This function can be used to make it easier to support localisable caches (where the cache // 2. Parse the key. > * could be stored on a local server as well as a shared cache). Specifying the version means $parsedkey = $this->parse_key($key); > * that it will automatically retrieve the correct version if available, either from the local > * server or [if that has an older version] from the shared server. // 3. Get it from the store. Obviously wasn't in the static acceleration array. > * $result = $this->store->get($parsedkey); > * If the cached version is newer than specified version, it will be returned regardless. For if ($result !== false) { > * example, if you request version 4, but the locally cached version is 5, it will be returned. if ($result instanceof cache_ttl_wrapper) { > * If you request version 6, and the locally cached version is 5, then the system will look in if ($result->has_expired()) { > * higher-level caches (if any); if there still isn't a version 6 or greater, it will return $this->store->delete($parsedkey); > * null. $result = false; > * } else { > * You must use this function if you use set_versioned. $result = $result->data; > * } > * @param string|int $key The key for the data being requested. } > * @param int $requiredversion Minimum required version of the data if ($usesstaticacceleration) { > * @param int $strictness One of IGNORE_MISSING or MUST_EXIST. $this->static_acceleration_set($key, $result); > * @param mixed $actualversion If specified, will be set to the actual version number retrieved } > * @return mixed Data from the cache, or false if the key did not exist or was too old if ($result instanceof cache_cached_object) { > * @throws \coding_exception If you call get_versioned on a non-versioned cache key $result = $result->restore_object(); > */ } > public function get_versioned($key, int $requiredversion, int $strictness = IGNORE_MISSING, &$actualversion = null) { } > return $this->get_implementation($key, $requiredversion, $strictness, $actualversion); > } // 4. Load if from the loader/datasource if we don't already have it. > $setaftervalidation = false; > /** if ($result === false) { > * Checks returned data to see if it matches the specified version number. if ($this->perfdebug) { > * cache_helper::record_cache_miss($this->store, $this->definition); > * For versioned data, this returns the version_wrapper object (or false). For other } > * data, it returns the actual data (or false). if ($this->loader !== false) { > * // We must pass the original (unparsed) key to the next loader in the chain. > * @param mixed $result Result data // The next loader will parse the key as it sees fit. It may be parsed differently > * @param int $requiredversion Required version number or VERSION_NONE if there must be no version // depending upon the capabilities of the store associated with the loader. > * @return bool True if version is current, false if not (or if result is false) $result = $this->loader->get($key); > * @throws \coding_exception If unexpected type of data (versioned vs non-versioned) is found } else if ($this->datasource !== false) { > */ $result = $this->datasource->load_for_cache($key); > protected static function check_version($result, int $requiredversion): bool { } > if ($requiredversion === self::VERSION_NONE) { $setaftervalidation = ($result !== false); > if ($result instanceof \core_cache\version_wrapper) { } else if ($this->perfdebug) { > throw new \coding_exception('Unexpectedly found versioned cache entry'); cache_helper::record_cache_hit($this->store, $this->definition); > } else { } > // No version checks, so version is always correct. // 5. Validate strictness. > return true; if ($strictness === MUST_EXIST && $result === false) { > } throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.'); > } else { } > // If there's no result, obviously it doesn't meet the required version. // 6. Set it to the store if we got it from the loader/datasource. > if (!cache_helper::result_found($result)) { if ($setaftervalidation) { > return false; $this->set($key, $result); > } } > if (!($result instanceof \core_cache\version_wrapper)) { // 7. Make sure we don't pass back anything that could be a reference. > throw new \coding_exception('Unexpectedly found non-versioned cache entry'); // We don't want people modifying the data in the cache. > } if (!$this->store->supports_dereferencing_objects() && !is_scalar($result)) { > // If the result doesn't match the required version tag, return false. // If data is an object it will be a reference. > if ($result->version < $requiredversion) { // If data is an array if may contain references. > return false; // We want to break references so that the cache cannot be modified outside of itself. > } // Call the function to unreference it (in the best way possible). > // The version meets the requirement. $result = $this->unref($result); > return true; } > } return $result; > } } > > /** /** > * Retrieves the value for the given key from the cache. * Retrieves an array of values for an array of keys. > * * > * @param string|int $key The key for the data being requested. * Using this function comes with potential performance implications. > * It can be any structure although using a scalar string or int is recommended in the interests of performance. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call > * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. * the equivalent singular method for each item provided. > * @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE * This should not deter you from using this function as there is a performance benefit in situations where the cache store > * @param int $strictness One of IGNORE_MISSING | MUST_EXIST * does support it, but you should be aware of this fact. > * @param mixed $actualversion If specified, will be set to the actual version number retrieved * > * @return mixed|false The data from the cache or false if the key did not exist within the cache. * @param array $keys The keys of the data being requested. > * @throws coding_exception * Each key can be any structure although using a scalar string or int is recommended in the interests of performance. > */ * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. > protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {
< if ($result !== false) {
> if (cache_helper::result_found($result) && self::check_version($result, $requiredversion)) { > if ($requiredversion === self::VERSION_NONE) {
* @return array An array of key value pairs for the items that could be retrieved from the cache.
> } else { * If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown. > $actualversion = $result->version; * Otherwise any key that did not exist will have a data value of false within the results. > return $result->data; * @throws coding_exception > }
< if ($result !== false) { < if ($result instanceof cache_ttl_wrapper) { < if ($result->has_expired()) {
> if (cache_helper::result_found($result)) { > // Check the result has at least the required version. > try { > $validversion = self::check_version($result, $requiredversion); > } catch (\coding_exception $e) { > // In certain circumstances this could happen before users are taken to the upgrade > // screen when upgrading from an earlier Moodle version that didn't use a versioned > // cache for this item, so redirect instead of showing error if that's the case. > redirect_if_major_upgrade_required(); > > // If we still get an exception because there is incorrect data in the cache (not > // versioned when it ought to be), delete it so this exception goes away next time. > // The exception should only happen if there is a code bug (which is why we still > // throw it) but there are unusual scenarios in development where it might happen > // and that would be annoying if it doesn't fix itself. > $this->store->delete($parsedkey); > throw $e; > } > > if (!$validversion) { > // If the result was too old, don't use it. > $result = false; > > // Also delete it immediately. This improves performance in the > // case when the cache item is large and there may be multiple clients simultaneously > // requesting it - they won't all have to do a megabyte of IO just in order to find > // that it's out of date. > $this->store->delete($parsedkey); > } > } > if (cache_helper::result_found($result)) { > // Look to see if there's a TTL wrapper. It might be inside a version wrapper. > if ($requiredversion !== self::VERSION_NONE) { > $ttlconsider = $result->data; > } else { > $ttlconsider = $result; > } > if ($ttlconsider instanceof cache_ttl_wrapper) { > if ($ttlconsider->has_expired()) {
$keysparsed = array();
> } else if ($requiredversion === self::VERSION_NONE) { $parsedkeys = array(); > // Use the data inside the TTL wrapper as the result. $resultpersist = array(); > $result = $ttlconsider->data;
< $result = $result->data;
> // Put the data from the TTL wrapper directly inside the version wrapper. > $result->data = $ttlconsider->data;
$keystofind = array();
> // Remove version wrapper if necessary. > if ($requiredversion !== self::VERSION_NONE) { // First up check the persist cache for each key. > $actualversion = $result->version; $isusingpersist = $this->use_static_acceleration(); > $result = $result->data; foreach ($keys as $key) { > }
< if ($result === false) {
> if (!cache_helper::result_found($result)) {
if (is_array($pkey)) {
> if ($requiredversion === self::VERSION_NONE) {
$pkey = $pkey['key'];
> } else { } > $result = $this->loader->get_versioned($key, $requiredversion, IGNORE_MISSING, $actualversion); $keysparsed[$key] = $pkey; > }
$parsedkeys[$pkey] = $key;
> if ($requiredversion === self::VERSION_NONE) {
$keystofind[$pkey] = $key;
> } else { if ($isusingpersist) { > if (!$this->datasource instanceof cache_data_source_versionable) { $value = $this->static_acceleration_get($key); > throw new \coding_exception('Data source is not versionable'); if ($value !== false) { > } $resultpersist[$pkey] = $value; > $result = $this->datasource->load_for_cache_versioned($key, $requiredversion, $actualversion); unset($keystofind[$pkey]); > if ($result && $actualversion < $requiredversion) { } > throw new \coding_exception('Data source returned outdated version'); } > }
< $setaftervalidation = ($result !== false);
> } > $setaftervalidation = (cache_helper::result_found($result));
< cache_helper::record_cache_hit($this->store, $this->definition);
> $readbytes = $this->store->get_last_io_bytes(); > cache_helper::record_cache_hit($this->store, $this->definition, 1, $readbytes);
< if ($strictness === MUST_EXIST && $result === false) {
> if ($strictness === MUST_EXIST && !cache_helper::result_found($result)) {
< // 6. Set it to the store if we got it from the loader/datasource.
> // 6. Set it to the store if we got it from the loader/datasource. Only set to this direct > // store; parent method will have set it to all stores if needed.
< $this->set($key, $result);
> $lock = null; > if (!empty($this->requirelockingbeforewrite)) { > $lock = $this->acquire_lock($key); > } > if ($requiredversion === self::VERSION_NONE) { > $this->set_implementation($key, self::VERSION_NONE, $result, false); > } else { > $this->set_implementation($key, $actualversion, $result, false); > } > if ($lock) { > $this->release_lock($key); > }
// Process each item in the result to "unwrap" it.
> $readbytes = cache_store::IO_BYTES_NOT_SUPPORTED;
foreach ($resultstore as $key => $value) {
> if ($this->perfdebug) { if ($value instanceof cache_ttl_wrapper) { > $readbytes = $this->store->get_last_io_bytes(); if ($value->has_expired()) { > }
$value = false; } else { $value = $value->data; } } if ($value !== false && $this->use_static_acceleration()) { $this->static_acceleration_set($keystofind[$key], $value); } if ($value instanceof cache_cached_object) { $value = $value->restore_object(); } $resultstore[$key] = $value; } } // Merge the result from the persis cache with the results from the store load. $result = $resultpersist + $resultstore; unset($resultpersist); unset($resultstore); // Next we need to find any missing values and load them from the loader/datasource next in the chain. $usingloader = ($this->loader !== false); $usingsource = (!$usingloader && ($this->datasource !== false)); if ($usingloader || $usingsource) { $missingkeys = array(); foreach ($result as $key => $value) { if ($value === false) { $missingkeys[] = $parsedkeys[$key]; } } if (!empty($missingkeys)) { if ($usingloader) { $resultmissing = $this->loader->get_many($missingkeys); } else { $resultmissing = $this->datasource->load_many_for_cache($missingkeys); } foreach ($resultmissing as $key => $value) { $result[$keysparsed[$key]] = $value;
> $lock = null; if ($value !== false) { > if (!empty($this->requirelockingbeforewrite)) { $this->set($key, $value); > $lock = $this->acquire_lock($key); } > }
}
> if ($lock) { unset($resultmissing); > $this->release_lock($key); } > }
unset($missingkeys); } // Create an array with the original keys and the found values. This will be what we return. $fullresult = array(); foreach ($result as $key => $value) { if (!is_scalar($value)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $value = $this->unref($value); } $fullresult[$parsedkeys[$key]] = $value; } unset($result); // Final step is to check strictness. if ($strictness === MUST_EXIST) { foreach ($keys as $key) { if (!array_key_exists($key, $fullresult)) { throw new coding_exception('Not all the requested keys existed within the cache stores.'); } } } if ($this->perfdebug) { $hits = 0; $misses = 0; foreach ($fullresult as $value) { if ($value === false) { $misses++; } else { $hits++; } }
< cache_helper::record_cache_hit($this->store, $this->definition, $hits);
> cache_helper::record_cache_hit($this->store, $this->definition, $hits, $readbytes);
cache_helper::record_cache_miss($this->store, $this->definition, $misses); } // Return the result. Phew! return $fullresult; } /** * Sends a key => value pair to the cache. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set('main', 'http://moodle.org'); * $cache->set('docs', 'http://docs.moodle.org'); * $cache->set('tracker', 'http://tracker.moodle.org'); * $cache->set('qa', 'http://qa.moodle.net'); * </code> * * @param string|int $key The key for the data being requested. * It can be any structure although using a scalar string or int is recommended in the interests of performance. * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. * @param mixed $data The data to set against the key. * @return bool True on success, false otherwise. */ public function set($key, $data) {
< if ($this->perfdebug) { < cache_helper::record_cache_set($this->store, $this->definition);
> return $this->set_implementation($key, self::VERSION_NONE, $data);
}
< if ($this->loader !== false) {
> > /** > * Sets the value for the given key with the given version. > * > * The cache does not store multiple versions - any existing version will be overwritten with > * this one. This function should only be used if there is a known 'current version' (e.g. > * stored in a database table). It only ensures that the cache does not return outdated data. > * > * This function can be used to help implement localisable caches (where the cache could be > * stored on a local server as well as a shared cache). The version will be recorded alongside > * the item and get_versioned will always return the correct version. > * > * The version number must be an integer that always increases. This could be based on the > * current time, or a stored value that increases by 1 each time it changes, etc. > * > * If you use this function you must use get_versioned to retrieve the data. > * > * @param string|int $key The key for the data being set. > * @param int $version Integer for the version of the data > * @param mixed $data The data to set against the key. > * @return bool True on success, false otherwise. > */ > public function set_versioned($key, int $version, $data): bool { > return $this->set_implementation($key, $version, $data); > } > > /** > * Sets the value for the given key, optionally with a version tag. > * > * @param string|int $key The key for the data being set. > * @param int $version Version number for the data or cache::VERSION_NONE if none > * @param mixed $data The data to set against the key. > * @param bool $setparents If true, sets all parent loaders, otherwise only this one > * @return bool True on success, false otherwise. > */ > protected function set_implementation($key, int $version, $data, bool $setparents = true): bool { > if ($this->loader !== false && $setparents) {
// We have a loader available set it there as well. // We have to let the loader do its own parsing of data as it may be unique.
> if ($version === self::VERSION_NONE) {
$this->loader->set($key, $data);
> } else { } > $this->loader->set_versioned($key, $version, $data); $usestaticacceleration = $this->use_static_acceleration(); > }
if (is_object($data) && $data instanceof cacheable_object) { $data = new cache_cached_object($data); } else if (!$this->store->supports_dereferencing_objects() && !is_scalar($data)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $data = $this->unref($data); } if ($usestaticacceleration) {
> // Static acceleration cache should include the cache version wrapper, but not TTL. $this->static_acceleration_set($key, $data); > if ($version === self::VERSION_NONE) {
}
> } else { > $this->static_acceleration_set($key, new \core_cache\version_wrapper($data, $version)); if ($this->has_a_ttl() && !$this->store_supports_native_ttl()) { > }
$data = new cache_ttl_wrapper($data, $this->definition->get_ttl()); } $parsedkey = $this->parse_key($key);
< return $this->store->set($parsedkey, $data);
> if ($version !== self::VERSION_NONE) { > $data = new \core_cache\version_wrapper($data, $version); > } > > $success = $this->store->set($parsedkey, $data); > if ($this->perfdebug) { > cache_helper::record_cache_set($this->store, $this->definition, 1, > $this->store->get_last_io_bytes()); > } > return $success;
} /** * Removes references where required. * * @param stdClass|array $data * @return mixed What ever was put in but without any references. */ protected function unref($data) { if ($this->definition->uses_simple_data()) { return $data; } // Check if it requires serialisation in order to produce a reference free copy. if ($this->requires_serialisation($data)) { // Damn, its going to have to be serialise. $data = serialize($data); // We unserialise immediately so that we don't have to do it every time on get. $data = unserialize($data); } else if (!is_scalar($data)) { // Its safe to clone, lets do it, its going to beat the pants of serialisation. $data = $this->deep_clone($data); } return $data; } /** * Checks to see if a var requires serialisation. * * @param mixed $value The value to check. * @param int $depth Used to ensure we don't enter an endless loop (think recursion). * @return bool Returns true if the value is going to require serialisation in order to ensure a reference free copy * or false if its safe to clone. */ protected function requires_serialisation($value, $depth = 1) { if (is_scalar($value)) { return false; } else if (is_array($value) || $value instanceof stdClass || $value instanceof Traversable) { if ($depth > 5) { // Skrew it, mega-deep object, developer you suck, we're just going to serialise. return true; } foreach ($value as $key => $subvalue) { if ($this->requires_serialisation($subvalue, $depth++)) { return true; } } } // Its not scalar, array, or stdClass so we'll need to serialise. return true; } /** * Creates a reference free clone of the given value. * * @param mixed $value * @return mixed */ protected function deep_clone($value) { if (is_object($value)) { // Objects must be cloned to begin with. $value = clone $value; } if (is_array($value) || is_object($value)) { foreach ($value as $key => $subvalue) { $value[$key] = $this->deep_clone($subvalue); } } return $value; } /** * Sends several key => value pairs to the cache. * * Using this function comes with potential performance implications. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call * the equivalent singular method for each item provided. * This should not deter you from using this function as there is a performance benefit in situations where the cache store * does support it, but you should be aware of this fact. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set_many(array( * 'main' => 'http://moodle.org', * 'docs' => 'http://docs.moodle.org', * 'tracker' => 'http://tracker.moodle.org', * 'qa' => ''http://qa.moodle.net' * )); * </code> * * @param array $keyvaluearray An array of key => value pairs to send to the cache. * @return int The number of items successfully set. It is up to the developer to check this matches the number of items. * ... if they care that is. */ public function set_many(array $keyvaluearray) { if ($this->loader !== false) { // We have a loader available set it there as well. // We have to let the loader do its own parsing of data as it may be unique. $this->loader->set_many($keyvaluearray); } $data = array(); $simulatettl = $this->has_a_ttl() && !$this->store_supports_native_ttl(); $usestaticaccelerationarray = $this->use_static_acceleration(); $needsdereferencing = !$this->store->supports_dereferencing_objects(); foreach ($keyvaluearray as $key => $value) { if (is_object($value) && $value instanceof cacheable_object) { $value = new cache_cached_object($value); } else if ($needsdereferencing && !is_scalar($value)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $value = $this->unref($value); } if ($usestaticaccelerationarray) { $this->static_acceleration_set($key, $value); } if ($simulatettl) { $value = new cache_ttl_wrapper($value, $this->definition->get_ttl()); } $data[$key] = array( 'key' => $this->parse_key($key), 'value' => $value ); } $successfullyset = $this->store->set_many($data); if ($this->perfdebug && $successfullyset) {
< cache_helper::record_cache_set($this->store, $this->definition, $successfullyset);
> cache_helper::record_cache_set($this->store, $this->definition, $successfullyset, > $this->store->get_last_io_bytes());
} return $successfullyset; } /** * Test is a cache has a key. * * The use of the has methods is strongly discouraged. In a high load environment the cache may well change between the * test and any subsequent action (get, set, delete etc). * Instead it is recommended to write your code in such a way they it performs the following steps: * <ol> * <li>Attempt to retrieve the information.</li> * <li>Generate the information.</li> * <li>Attempt to set the information</li> * </ol> * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param string|int $key * @param bool $tryloadifpossible If set to true, the cache doesn't contain the key, and there is another cache loader or * data source then the code will try load the key value from the next item in the chain. * @return bool True if the cache has the requested key, false otherwise. */ public function has($key, $tryloadifpossible = false) { if ($this->static_acceleration_has($key)) { // Hoorah, that was easy. It exists in the static acceleration array so we definitely have it. return true; } $parsedkey = $this->parse_key($key); if ($this->has_a_ttl() && !$this->store_supports_native_ttl()) { // The data has a TTL and the store doesn't support it natively. // We must fetch the data and expect a ttl wrapper. $data = $this->store->get($parsedkey); $has = ($data instanceof cache_ttl_wrapper && !$data->has_expired()); } else if (!$this->store_supports_key_awareness()) { // The store doesn't support key awareness, get the data and check it manually... puke. // Either no TTL is set of the store supports its handling natively. $data = $this->store->get($parsedkey); $has = ($data !== false); } else { // The store supports key awareness, this is easy! // Either no TTL is set of the store supports its handling natively. $has = $this->store->has($parsedkey); } if (!$has && $tryloadifpossible) { if ($this->loader !== false) { $result = $this->loader->get($parsedkey); } else if ($this->datasource !== null) { $result = $this->datasource->load_for_cache($key); } $has = ($result !== null); if ($has) { $this->set($key, $result); } } return $has; } /** * Test is a cache has all of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has all of the given keys, false otherwise. */ public function has_all(array $keys) { if (($this->has_a_ttl() && !$this->store_supports_native_ttl()) || !$this->store_supports_key_awareness()) { foreach ($keys as $key) { if (!$this->has($key)) { return false; } } return true; } $parsedkeys = array_map(array($this, 'parse_key'), $keys); return $this->store->has_all($parsedkeys); } /** * Test if a cache has at least one of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has at least one of the given keys */ public function has_any(array $keys) { if (($this->has_a_ttl() && !$this->store_supports_native_ttl()) || !$this->store_supports_key_awareness()) { foreach ($keys as $key) { if ($this->has($key)) { return true; } } return false; } if ($this->use_static_acceleration()) { foreach ($keys as $id => $key) { if ($this->static_acceleration_has($key)) { return true; } } } $parsedkeys = array_map(array($this, 'parse_key'), $keys); return $this->store->has_any($parsedkeys); } /** * Delete the given key from the cache. * * @param string|int $key The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return bool True of success, false otherwise. */ public function delete($key, $recurse = true) { $this->static_acceleration_delete($key); if ($recurse && $this->loader !== false) { // Delete from the bottom of the stack first. $this->loader->delete($key, $recurse); } $parsedkey = $this->parse_key($key); return $this->store->delete($parsedkey); } /** * Delete all of the given keys from the cache. * * @param array $keys The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return int The number of items successfully deleted. */ public function delete_many(array $keys, $recurse = true) { if ($this->use_static_acceleration()) { foreach ($keys as $key) { $this->static_acceleration_delete($key); } } if ($recurse && $this->loader !== false) { // Delete from the bottom of the stack first. $this->loader->delete_many($keys, $recurse); } $parsedkeys = array_map(array($this, 'parse_key'), $keys); return $this->store->delete_many($parsedkeys); } /** * Purges the cache store, and loader if there is one. * * @return bool True on success, false otherwise */ public function purge() { // 1. Purge the static acceleration array. $this->static_acceleration_purge(); // 2. Purge the store. $this->store->purge(); // 3. Optionally pruge any stacked loaders. if ($this->loader) { $this->loader->purge(); } return true; } /** * Parses the key turning it into a string (or array is required) suitable to be passed to the cache store. * * @param string|int $key As passed to get|set|delete etc. * @return string|array String unless the store supports multi-identifiers in which case an array if returned. */ protected function parse_key($key) { // First up if the store supports multiple keys we'll go with that. if ($this->store->supports_multiple_identifiers()) { $result = $this->definition->generate_multi_key_parts(); $result['key'] = $key; return $result; } // If not we need to generate a hash and to for that we use the cache_helper. return cache_helper::hash_key($key, $this->definition); } /** * Returns true if the cache is making use of a ttl. * @return bool */ protected function has_a_ttl() { return $this->hasattl; } /** * Returns true if the cache store supports native ttl. * @return bool */ protected function store_supports_native_ttl() { if ($this->supportsnativettl === null) { $this->supportsnativettl = ($this->store->supports_native_ttl()); } return $this->supportsnativettl; } /** * Returns the cache definition. * * @return cache_definition */ protected function get_definition() { return $this->definition; } /** * Returns the cache store * * @return cache_store */ protected function get_store() { return $this->store; } /** * Returns the loader associated with this instance. * * @since Moodle 2.4.4 * @return cache|false */ protected function get_loader() { return $this->loader; } /** * Returns the data source associated with this cache. * * @since Moodle 2.4.4 * @return cache_data_source|false */ protected function get_datasource() { return $this->datasource; } /** * Returns true if the store supports key awareness. * * @return bool */ protected function store_supports_key_awareness() { if ($this->supportskeyawareness === null) { $this->supportskeyawareness = ($this->store instanceof cache_is_key_aware); } return $this->supportskeyawareness; } /** * Returns true if the store natively supports locking. * * @return bool */ protected function store_supports_native_locking() { if ($this->nativelocking === null) { $this->nativelocking = ($this->store instanceof cache_is_lockable); } return $this->nativelocking; } /** * @deprecated since 2.6 * @see cache::use_static_acceleration() */ protected function is_using_persist_cache() { throw new coding_exception('cache::is_using_persist_cache() can not be used anymore.' . ' Please use cache::use_static_acceleration() instead.'); } /** * Returns true if this cache is making use of the static acceleration array. * * @return bool */ protected function use_static_acceleration() { return $this->staticacceleration; } /** * @see cache::static_acceleration_has * @deprecated since 2.6 */ protected function is_in_persist_cache() { throw new coding_exception('cache::is_in_persist_cache() can not be used anymore.' . ' Please use cache::static_acceleration_has() instead.'); } /** * Returns true if the requested key exists within the static acceleration array. * * @param string $key The parsed key * @return bool */ protected function static_acceleration_has($key) { // This could be written as a single line, however it has been split because the ttl check is faster than the instanceof // and has_expired calls. if (!$this->staticacceleration || !isset($this->staticaccelerationarray[$key])) { return false; } return true; } /** * @deprecated since 2.6 * @see cache::static_acceleration_get */ protected function get_from_persist_cache() { throw new coding_exception('cache::get_from_persist_cache() can not be used anymore.' . ' Please use cache::static_acceleration_get() instead.'); } /** * Returns the item from the static acceleration array if it exists there. * * @param string $key The parsed key * @return mixed|false Dereferenced data from the static acceleration array or false if it wasn't there. */ protected function static_acceleration_get($key) { if (!$this->staticacceleration || !isset($this->staticaccelerationarray[$key])) { $result = false; } else { $data = $this->staticaccelerationarray[$key]['data']; if ($data instanceof cache_cached_object) { $result = $data->restore_object(); } else if ($this->staticaccelerationarray[$key]['serialized']) { $result = unserialize($data); } else { $result = $data; } }
< if ($result !== false) {
> if (cache_helper::result_found($result)) {
if ($this->perfdebug) { cache_helper::record_cache_hit(cache_store::STATIC_ACCEL, $this->definition); } if ($this->staticaccelerationsize > 1 && $this->staticaccelerationcount > 1) { // Check to see if this is the last item on the static acceleration keys array. if (end($this->staticaccelerationkeys) !== $key) { // It isn't the last item. // Move the item to the end of the array so that it is last to be removed. unset($this->staticaccelerationkeys[$key]); $this->staticaccelerationkeys[$key] = $key; } } return $result; } else { if ($this->perfdebug) { cache_helper::record_cache_miss(cache_store::STATIC_ACCEL, $this->definition); } return false; } } /** * @deprecated since 2.6 * @see cache::static_acceleration_set */ protected function set_in_persist_cache() { throw new coding_exception('cache::set_in_persist_cache() can not be used anymore.' . ' Please use cache::static_acceleration_set() instead.'); } /** * Sets a key value pair into the static acceleration array. * * @param string $key The parsed key * @param mixed $data * @return bool */ protected function static_acceleration_set($key, $data) { if ($this->staticaccelerationsize !== false && isset($this->staticaccelerationkeys[$key])) { $this->staticaccelerationcount--; unset($this->staticaccelerationkeys[$key]); } // We serialize anything that's not; // 1. A known scalar safe value. // 2. A definition that says it's simpledata. We trust it that it doesn't contain dangerous references. // 3. An object that handles dereferencing by itself. if (is_scalar($data) || $this->definition->uses_simple_data() || $data instanceof cache_cached_object) { $this->staticaccelerationarray[$key]['data'] = $data; $this->staticaccelerationarray[$key]['serialized'] = false; } else { $this->staticaccelerationarray[$key]['data'] = serialize($data); $this->staticaccelerationarray[$key]['serialized'] = true; } if ($this->staticaccelerationsize !== false) { $this->staticaccelerationcount++; $this->staticaccelerationkeys[$key] = $key; if ($this->staticaccelerationcount > $this->staticaccelerationsize) { $dropkey = array_shift($this->staticaccelerationkeys); unset($this->staticaccelerationarray[$dropkey]); $this->staticaccelerationcount--; } } return true; } /** * @deprecated since 2.6 * @see cache::static_acceleration_delete() */ protected function delete_from_persist_cache() { throw new coding_exception('cache::delete_from_persist_cache() can not be used anymore.' . ' Please use cache::static_acceleration_delete() instead.'); } /** * Deletes an item from the static acceleration array. * * @param string|int $key As given to get|set|delete * @return bool True on success, false otherwise. */ protected function static_acceleration_delete($key) { unset($this->staticaccelerationarray[$key]); if ($this->staticaccelerationsize !== false && isset($this->staticaccelerationkeys[$key])) { unset($this->staticaccelerationkeys[$key]); $this->staticaccelerationcount--; } return true; } /** * Purge the static acceleration cache. */ protected function static_acceleration_purge() { $this->staticaccelerationarray = array(); if ($this->staticaccelerationsize !== false) { $this->staticaccelerationkeys = array(); $this->staticaccelerationcount = 0; } } /** * Returns the timestamp from the first request for the time from the cache API. * * This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with * timing issues. * * @param bool $float Whether to use floating precision accuracy. * @return int|float */ public static function now($float = false) { if (self::$now === null) { self::$now = microtime(true); } if ($float) { return self::$now; } else { return (int) self::$now; } } /** * Get a 'purge' token used for cache invalidation handling. * * Note: This function is intended for use from within the Cache API only and not by plugins, or cache stores. * * @param bool $reset Whether to reset the token and generate a new one. * @return string */ public static function get_purge_token($reset = false) { if (self::$purgetoken === null || $reset) { self::$now = null; self::$purgetoken = self::now(true) . '-' . uniqid('', true); } return self::$purgetoken; } /** * Compare a pair of purge tokens. * * If the two tokens are identical, then the return value is 0. * If the time component of token A is newer than token B, then a positive value is returned. * If the time component of token B is newer than token A, then a negative value is returned. * * Note: This function is intended for use from within the Cache API only and not by plugins, or cache stores. * * @param string $tokena * @param string $tokenb * @return int */ public static function compare_purge_tokens($tokena, $tokenb) { if ($tokena === $tokenb) { // There is an exact match. return 0; } // The token for when the cache was last invalidated. list($atime) = explode('-', "{$tokena}-", 2); // The token for this cache. list($btime) = explode('-', "{$tokenb}-", 2); if ($atime >= $btime) { // Token A is newer. return 1; } else { // Token A is older. return -1; } } /** * Subclasses may support purging cache of all data belonging to the * current user. */ public function purge_current_user() { } } /** * An application cache. * * This class is used for application caches returned by the cache::make methods. * On top of the standard functionality it also allows locking to be required and or manually operated. * * This cache class should never be interacted with directly. Instead you should always use the cache::make methods. * It is technically possible to call those methods through this class however there is no guarantee that you will get an * instance of this class back again. * * @internal don't use me directly. * * @package core * @category cache * @copyright 2012 Sam Hemelryk * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class cache_application extends cache implements cache_loader_with_locking { /** * Lock identifier. * This is used to ensure the lock belongs to the cache instance + definition + user. * @var string */ protected $lockidentifier; /** * Gets set to true if the cache's primary store natively supports locking. * If it does then we use that, otherwise we need to instantiate a second store to use for locking. * @var cache_store */ protected $nativelocking = null; /** * Gets set to true if the cache is going to be using locking. * This isn't a requirement, it doesn't need to use locking (most won't) and this bool is used to quickly check things. * If required then locking will be forced for the get|set|delete operation. * @var bool */ protected $requirelocking = false; /** * Gets set to true if the cache must use read locking (get|has). * @var bool */ protected $requirelockingread = false; /** * Gets set to true if the cache must use write locking (set|delete) * @var bool */ protected $requirelockingwrite = false; /**
> * Gets set to true if the cache writes (set|delete) must have a manual lock created first * Gets set to a cache_store to use for locking if the caches primary store doesn't support locking natively. > * @var bool * @var cache_lock_interface > */ */ > protected $requirelockingbeforewrite = false; protected $cachelockinstance; > > /**
/**
> * Store a list of locks acquired by this process. * Overrides the cache construct method. > * @var array * > */ * You should not call this method from your code, instead you should use the cache::make methods. > protected $locks; * > * @param cache_definition $definition > /**
* @param cache_store $store * @param cache_loader|cache_data_source $loader */ public function __construct(cache_definition $definition, cache_store $store, $loader = null) { parent::__construct($definition, $store, $loader); $this->nativelocking = $this->store_supports_native_locking(); if ($definition->require_locking()) { $this->requirelocking = true; $this->requirelockingread = $definition->require_locking_read(); $this->requirelockingwrite = $definition->require_locking_write();
> $this->requirelockingbeforewrite = $definition->require_locking_before_write();
} $this->handle_invalidation_events(); } /** * Returns the identifier to use * * @staticvar int $instances Counts the number of instances. Used as part of the lock identifier. * @return string */ public function get_identifier() { static $instances = 0; if ($this->lockidentifier === null) { $this->lockidentifier = md5( $this->get_definition()->generate_definition_hash() . sesskey() . $instances++ . 'cache_application' ); } return $this->lockidentifier; } /** * Fixes the instance up after a clone. */ public function __clone() { // Force a new idenfitier. $this->lockidentifier = null; } /** * Acquires a lock on the given key. * * This is done automatically if the definition requires it. * It is recommended to use a definition if you want to have locking although it is possible to do locking without having * it required by the definition. * The problem with such an approach is that you cannot ensure that code will consistently use locking. You will need to * rely on the integrators review skills. * * @param string|int $key The key as given to get|set|delete * @return bool Returns true if the lock could be acquired, false otherwise. */ public function acquire_lock($key) {
< $key = $this->parse_key($key);
> $releaseparent = false; > if ($this->get_loader() !== false) { > if (!$this->get_loader()->acquire_lock($key)) { > return false; > } > // We need to release this lock later if the lock is not successful. > $releaseparent = true; > } > $hashedkey = cache_helper::hash_key($key, $this->get_definition()); > $before = microtime(true);
if ($this->nativelocking) {
< return $this->get_store()->acquire_lock($key, $this->get_identifier());
> $lock = $this->get_store()->acquire_lock($hashedkey, $this->get_identifier());
} else { $this->ensure_cachelock_available();
< return $this->cachelockinstance->lock($key, $this->get_identifier());
> $lock = $this->cachelockinstance->lock($hashedkey, $this->get_identifier()); > } > $after = microtime(true); > if ($lock) { > $this->locks[$hashedkey] = $lock; > if ((defined('MDL_PERF') && MDL_PERF) || $this->perfdebug) { > \core\lock\timing_wrapper_lock_factory::record_lock_data($after, $before, > $this->get_definition()->get_id(), $hashedkey, $lock, $this->get_identifier() . $hashedkey); > } > } else { > // If we successfully got the parent lock, but are now failing to get this lock, then we should release > // the parent one. > if ($releaseparent) { > $this->get_loader()->release_lock($key); > }
}
> return $lock;
} /** * Checks if this cache has a lock on the given key. * * @param string|int $key The key as given to get|set|delete * @return bool|null Returns true if there is a lock and this cache has it, null if no one has a lock on that key, false if * someone else has the lock. */ public function check_lock_state($key) {
< $key = $this->parse_key($key);
> $key = cache_helper::hash_key($key, $this->get_definition()); > if (!empty($this->locks[$key])) { > return true; // Shortcut to save having to make a call to the cache store if the lock is held by this process. > }
if ($this->nativelocking) { return $this->get_store()->check_lock_state($key, $this->get_identifier()); } else { $this->ensure_cachelock_available(); return $this->cachelockinstance->check_state($key, $this->get_identifier()); } } /** * Releases the lock this cache has on the given key * * @param string|int $key * @return bool True if the operation succeeded, false otherwise. */ public function release_lock($key) {
< $key = $this->parse_key($key);
> $loaderkey = $key; > $key = cache_helper::hash_key($key, $this->get_definition());
if ($this->nativelocking) {
< return $this->get_store()->release_lock($key, $this->get_identifier());
> $released = $this->get_store()->release_lock($key, $this->get_identifier());
} else { $this->ensure_cachelock_available();
< return $this->cachelockinstance->unlock($key, $this->get_identifier());
> $released = $this->cachelockinstance->unlock($key, $this->get_identifier());
}
> if ($released && array_key_exists($key, $this->locks)) { } > unset($this->locks[$key]); > if ((defined('MDL_PERF') && MDL_PERF) || $this->perfdebug) { /** > \core\lock\timing_wrapper_lock_factory::record_lock_released_data($this->get_identifier() . $key); * Ensure that the dedicated lock store is ready to go. > } * > } * This should only happen if the cache store doesn't natively support it. > if ($this->get_loader() !== false) { */ > $this->get_loader()->release_lock($loaderkey); protected function ensure_cachelock_available() { > } if ($this->cachelockinstance === null) { > return $released;
$this->cachelockinstance = cache_helper::get_cachelock_for_store($this->get_store()); } } /** * Sends a key => value pair to the cache. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set('main', 'http://moodle.org'); * $cache->set('docs', 'http://docs.moodle.org'); * $cache->set('tracker', 'http://tracker.moodle.org'); * $cache->set('qa', 'http://qa.moodle.net'); * </code> * * @param string|int $key The key for the data being requested.
> * @param int $version Version number
* @param mixed $data The data to set against the key.
> * @param bool $setparents If true, sets all parent loaders, otherwise only this one
* @return bool True on success, false otherwise. */
< public function set($key, $data) {
> protected function set_implementation($key, int $version, $data, bool $setparents = true): bool { > if ($this->requirelockingbeforewrite && !$this->check_lock_state($key)) { > throw new coding_exception('Attempted to set cache key "' . $key . '" without a lock. ' > . 'Locking before writes is required for ' . $this->get_definition()->get_id()); > }
if ($this->requirelockingwrite && !$this->acquire_lock($key)) { return false; }
< $result = parent::set($key, $data);
> $result = parent::set_implementation($key, $version, $data, $setparents);
if ($this->requirelockingwrite && !$this->release_lock($key)) { debugging('Failed to release cache lock on set operation... this should not happen.', DEBUG_DEVELOPER); } return $result; } /** * Sends several key => value pairs to the cache. * * Using this function comes with potential performance implications. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call * the equivalent singular method for each item provided. * This should not deter you from using this function as there is a performance benefit in situations where the cache store * does support it, but you should be aware of this fact. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set_many(array( * 'main' => 'http://moodle.org', * 'docs' => 'http://docs.moodle.org', * 'tracker' => 'http://tracker.moodle.org', * 'qa' => ''http://qa.moodle.net' * )); * </code> * * @param array $keyvaluearray An array of key => value pairs to send to the cache. * @return int The number of items successfully set. It is up to the developer to check this matches the number of items. * ... if they care that is. */ public function set_many(array $keyvaluearray) {
> if ($this->requirelockingbeforewrite) { if ($this->requirelockingwrite) { > foreach ($keyvaluearray as $key => $value) { $locks = array(); > if (!$this->check_lock_state($key)) { foreach ($keyvaluearray as $id => $pair) { > debugging('Attempted to set cache key "' . $key . '" without a lock. ' $key = $pair['key']; > . 'Locking before writes is required for ' . $this->get_definition()->get_name(), DEBUG_DEVELOPER); if ($this->acquire_lock($key)) { > unset($keyvaluearray[$key]); $locks[] = $key; > } } else { > } unset($keyvaluearray[$id]); > }
} } } $result = parent::set_many($keyvaluearray); if ($this->requirelockingwrite) { foreach ($locks as $key) { if ($this->release_lock($key)) { debugging('Failed to release cache lock on set_many operation... this should not happen.', DEBUG_DEVELOPER); } } } return $result; } /** * Retrieves the value for the given key from the cache. * * @param string|int $key The key for the data being requested.
> * @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE
* @param int $strictness One of IGNORE_MISSING | MUST_EXIST
> * @param mixed &$actualversion If specified, will be set to the actual version number retrieved
* @return mixed|false The data from the cache or false if the key did not exist within the cache. */
< public function get($key, $strictness = IGNORE_MISSING) {
> protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {
if ($this->requirelockingread && $this->check_lock_state($key) === false) { // Read locking required and someone else has the read lock. return false; }
< return parent::get($key, $strictness);
> return parent::get_implementation($key, $requiredversion, $strictness, $actualversion);
} /** * Retrieves an array of values for an array of keys. * * Using this function comes with potential performance implications. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call * the equivalent singular method for each item provided. * This should not deter you from using this function as there is a performance benefit in situations where the cache store * does support it, but you should be aware of this fact. * * @param array $keys The keys of the data being requested. * @param int $strictness One of IGNORE_MISSING or MUST_EXIST. * @return array An array of key value pairs for the items that could be retrieved from the cache. * If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown. * Otherwise any key that did not exist will have a data value of false within the results. * @throws coding_exception */ public function get_many(array $keys, $strictness = IGNORE_MISSING) {
> $locks = [];
if ($this->requirelockingread) { foreach ($keys as $id => $key) {
< $lock =$this->acquire_lock($key); < if (!$lock) {
> $locks[$key] = $this->acquire_lock($key); > if (!$locks[$key]) {
if ($strictness === MUST_EXIST) { throw new coding_exception('Could not acquire read locks for all of the items being requested.'); } else { // Can't return this as we couldn't get a read lock. unset($keys[$id]); } } } }
< return parent::get_many($keys, $strictness);
> $result = parent::get_many($keys, $strictness); > if ($this->requirelockingread) { > foreach ($locks as $key => $lock) { > $this->release_lock($key); > } > } > return $result;
} /** * Delete the given key from the cache. * * @param string|int $key The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return bool True of success, false otherwise. */ public function delete($key, $recurse = true) { if ($this->requirelockingwrite && !$this->acquire_lock($key)) { return false; } $result = parent::delete($key, $recurse); if ($this->requirelockingwrite && !$this->release_lock($key)) { debugging('Failed to release cache lock on delete operation... this should not happen.', DEBUG_DEVELOPER); } return $result; } /** * Delete all of the given keys from the cache. * * @param array $keys The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return int The number of items successfully deleted. */ public function delete_many(array $keys, $recurse = true) { if ($this->requirelockingwrite) { $locks = array(); foreach ($keys as $id => $key) { if ($this->acquire_lock($key)) { $locks[] = $key; } else { unset($keys[$id]); } } } $result = parent::delete_many($keys, $recurse); if ($this->requirelockingwrite) { foreach ($locks as $key) { if ($this->release_lock($key)) { debugging('Failed to release cache lock on delete_many operation... this should not happen.', DEBUG_DEVELOPER); } } } return $result; } } /** * A session cache. * * This class is used for session caches returned by the cache::make methods. * * It differs from the application loader in a couple of noteable ways: * 1. Sessions are always expected to exist. * Because of this we don't ever use the static acceleration array. * 2. Session data for a loader instance (store + definition) is consolidate into a * single array for storage within the store. * Along with this we embed a lastaccessed time with the data. This way we can * check sessions for a last access time. * 3. Session stores are required to support key searching and must * implement cache_is_searchable. This ensures stores used for the cache can be * targetted for garbage collection of session data. * * This cache class should never be interacted with directly. Instead you should always use the cache::make methods. * It is technically possible to call those methods through this class however there is no guarantee that you will get an * instance of this class back again. * * @todo we should support locking in the session as well. Should be pretty simple to set up. * * @internal don't use me directly. * @method cache_store|cache_is_searchable get_store() Returns the cache store which must implement both cache_is_searchable. * * @package core * @category cache * @copyright 2012 Sam Hemelryk * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class cache_session extends cache { /** * The user the session has been established for. * @var int */ protected static $loadeduserid = null; /** * The userid this cache is currently using. * @var int */ protected $currentuserid = null; /** * The session id we are currently using. * @var array */ protected $sessionid = null; /** * The session data for the above session id. * @var array */ protected $session = null; /** * Constant used to prefix keys. */ const KEY_PREFIX = 'sess_'; /** * This is the key used to track last access. */ const LASTACCESS = '__lastaccess__'; /** * Override the cache::construct method. * * This function gets overriden so that we can process any invalidation events if need be. * If the definition doesn't have any invalidation events then this occurs exactly as it would for the cache class. * Otherwise we look at the last invalidation time and then check the invalidation data for events that have occured * between then now. * * You should not call this method from your code, instead you should use the cache::make methods. * * @param cache_definition $definition * @param cache_store $store * @param cache_loader|cache_data_source $loader */ public function __construct(cache_definition $definition, cache_store $store, $loader = null) { // First up copy the loadeduserid to the current user id. $this->currentuserid = self::$loadeduserid; $this->set_session_id(); parent::__construct($definition, $store, $loader); // This will trigger check tracked user. If this gets removed a call to that will need to be added here in its place. $this->set(self::LASTACCESS, cache::now()); $this->handle_invalidation_events(); } /** * Sets the session id for the loader. */ protected function set_session_id() { $this->sessionid = preg_replace('#[^a-zA-Z0-9_]#', '_', session_id()); } /** * Returns the prefix used for all keys. * @return string */ protected function get_key_prefix() { return 'u'.$this->currentuserid.'_'.$this->sessionid; } /** * Parses the key turning it into a string (or array is required) suitable to be passed to the cache store. * * This function is called for every operation that uses keys. For this reason we use this function to also check * that the current user is the same as the user who last used this cache. * * On top of that if prepends the string 'sess_' to the start of all keys. The _ ensures things are easily identifiable. * * @param string|int $key As passed to get|set|delete etc. * @return string|array String unless the store supports multi-identifiers in which case an array if returned. */ protected function parse_key($key) { $prefix = $this->get_key_prefix(); if ($key === self::LASTACCESS) { return $key.$prefix; } return $prefix.'_'.parent::parse_key($key); } /** * Check that this cache instance is tracking the current user. */ protected function check_tracked_user() { if (isset($_SESSION['USER']->id) && $_SESSION['USER']->id !== null) { // Get the id of the current user. $new = $_SESSION['USER']->id; } else { // No user set up yet. $new = 0; } if ($new !== self::$loadeduserid) { // The current user doesn't match the tracked userid for this request. if (!is_null(self::$loadeduserid)) { // Purge the data we have for the old user. // This way we don't bloat the session. $this->purge(); } self::$loadeduserid = $new; $this->currentuserid = $new; } else if ($new !== $this->currentuserid) { // The current user matches the loaded user but not the user last used by this cache. $this->purge_current_user(); $this->currentuserid = $new; } } /** * Purges the session cache of all data belonging to the current user. */ public function purge_current_user() { $keys = $this->get_store()->find_by_prefix($this->get_key_prefix()); $this->get_store()->delete_many($keys); } /** * Retrieves the value for the given key from the cache. * * @param string|int $key The key for the data being requested. * It can be any structure although using a scalar string or int is recommended in the interests of performance. * In advanced cases an array may be useful such as in situations requiring the multi-key functionality.
> * @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE
* @param int $strictness One of IGNORE_MISSING | MUST_EXIST
> * @param mixed &$actualversion If specified, will be set to the actual version number retrieved
* @return mixed|false The data from the cache or false if the key did not exist within the cache. * @throws coding_exception */
< public function get($key, $strictness = IGNORE_MISSING) {
> protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {
// Check the tracked user. $this->check_tracked_user();
< // 2. Parse the key. < $parsedkey = $this->parse_key($key); < // 3. Get it from the store. < $result = $this->get_store()->get($parsedkey); < if ($result !== false) { < if ($result instanceof cache_ttl_wrapper) { < if ($result->has_expired()) { < $this->get_store()->delete($parsedkey); < $result = false; < } else { < $result = $result->data; < } < } < if ($result instanceof cache_cached_object) { < $result = $result->restore_object(); < } < } < // 4. Load if from the loader/datasource if we don't already have it. < if ($result === false) { < if ($this->perfdebug) { < cache_helper::record_cache_miss($this->get_store(), $this->get_definition()); < } < if ($this->get_loader() !== false) { < // We must pass the original (unparsed) key to the next loader in the chain. < // The next loader will parse the key as it sees fit. It may be parsed differently < // depending upon the capabilities of the store associated with the loader. < $result = $this->get_loader()->get($key); < } else if ($this->get_datasource() !== false) { < $result = $this->get_datasource()->load_for_cache($key); < } < // 5. Set it to the store if we got it from the loader/datasource. < if ($result !== false) { < $this->set($key, $result); < } < } else if ($this->perfdebug) { < cache_helper::record_cache_hit($this->get_store(), $this->get_definition()); < } < // 5. Validate strictness. < if ($strictness === MUST_EXIST && $result === false) { < throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.'); < } < // 6. Make sure we don't pass back anything that could be a reference. < // We don't want people modifying the data in the cache. < if (!$this->get_store()->supports_dereferencing_objects() && !is_scalar($result)) { < // If data is an object it will be a reference. < // If data is an array if may contain references. < // We want to break references so that the cache cannot be modified outside of itself. < // Call the function to unreference it (in the best way possible). < $result = $this->unref($result); < } < return $result;
> > // Use parent code. > return parent::get_implementation($key, $requiredversion, $strictness, $actualversion);
} /** * Sends a key => value pair to the cache. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set('main', 'http://moodle.org'); * $cache->set('docs', 'http://docs.moodle.org'); * $cache->set('tracker', 'http://tracker.moodle.org'); * $cache->set('qa', 'http://qa.moodle.net'); * </code> * * @param string|int $key The key for the data being requested. * It can be any structure although using a scalar string or int is recommended in the interests of performance. * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. * @param mixed $data The data to set against the key. * @return bool True on success, false otherwise. */ public function set($key, $data) { $this->check_tracked_user(); $loader = $this->get_loader(); if ($loader !== false) { // We have a loader available set it there as well. // We have to let the loader do its own parsing of data as it may be unique. $loader->set($key, $data); }
< if ($this->perfdebug) { < cache_helper::record_cache_set($this->get_store(), $this->get_definition()); < }
if (is_object($data) && $data instanceof cacheable_object) { $data = new cache_cached_object($data); } else if (!$this->get_store()->supports_dereferencing_objects() && !is_scalar($data)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $data = $this->unref($data); } // We dont' support native TTL here as we consolidate data for sessions. if ($this->has_a_ttl() && !$this->store_supports_native_ttl()) { $data = new cache_ttl_wrapper($data, $this->get_definition()->get_ttl()); }
< return $this->get_store()->set($this->parse_key($key), $data);
> $success = $this->get_store()->set($this->parse_key($key), $data); > if ($this->perfdebug) { > cache_helper::record_cache_set($this->get_store(), $this->get_definition(), 1, > $this->get_store()->get_last_io_bytes()); > } > return $success;
} /** * Delete the given key from the cache. * * @param string|int $key The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return bool True of success, false otherwise. */ public function delete($key, $recurse = true) { $parsedkey = $this->parse_key($key); if ($recurse && $this->get_loader() !== false) { // Delete from the bottom of the stack first. $this->get_loader()->delete($key, $recurse); } return $this->get_store()->delete($parsedkey); } /** * Retrieves an array of values for an array of keys. * * Using this function comes with potential performance implications. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call * the equivalent singular method for each item provided. * This should not deter you from using this function as there is a performance benefit in situations where the cache store * does support it, but you should be aware of this fact. * * @param array $keys The keys of the data being requested. * Each key can be any structure although using a scalar string or int is recommended in the interests of performance. * In advanced cases an array may be useful such as in situations requiring the multi-key functionality. * @param int $strictness One of IGNORE_MISSING or MUST_EXIST. * @return array An array of key value pairs for the items that could be retrieved from the cache. * If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown. * Otherwise any key that did not exist will have a data value of false within the results. * @throws coding_exception */ public function get_many(array $keys, $strictness = IGNORE_MISSING) { $this->check_tracked_user(); $parsedkeys = array(); $keymap = array(); foreach ($keys as $key) { $parsedkey = $this->parse_key($key); $parsedkeys[$key] = $parsedkey; $keymap[$parsedkey] = $key; } $result = $this->get_store()->get_many($parsedkeys);
> if ($this->perfdebug) { $return = array(); > $readbytes = $this->get_store()->get_last_io_bytes(); $missingkeys = array(); > }
$hasmissingkeys = false; foreach ($result as $parsedkey => $value) { $key = $keymap[$parsedkey]; if ($value instanceof cache_ttl_wrapper) { /* @var cache_ttl_wrapper $value */ if ($value->has_expired()) { $this->delete($keymap[$parsedkey]); $value = false; } else { $value = $value->data; } } if ($value instanceof cache_cached_object) { /* @var cache_cached_object $value */ $value = $value->restore_object(); } else if (!$this->get_store()->supports_dereferencing_objects() && !is_scalar($value)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $value = $this->unref($value); } $return[$key] = $value; if ($value === false) { $hasmissingkeys = true; $missingkeys[$parsedkey] = $key; } } if ($hasmissingkeys) { // We've got missing keys - we've got to check any loaders or data sources. $loader = $this->get_loader(); $datasource = $this->get_datasource(); if ($loader !== false) { foreach ($loader->get_many($missingkeys) as $key => $value) { if ($value !== false) { $return[$key] = $value; unset($missingkeys[$parsedkeys[$key]]); } } } $hasmissingkeys = count($missingkeys) > 0; if ($datasource !== false && $hasmissingkeys) { // We're still missing keys but we've got a datasource. foreach ($datasource->load_many_for_cache($missingkeys) as $key => $value) { if ($value !== false) { $return[$key] = $value; unset($missingkeys[$parsedkeys[$key]]); } } $hasmissingkeys = count($missingkeys) > 0; } } if ($hasmissingkeys && $strictness === MUST_EXIST) { throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.'); } if ($this->perfdebug) { $hits = 0; $misses = 0; foreach ($return as $value) { if ($value === false) { $misses++; } else { $hits++; } }
< cache_helper::record_cache_hit($this->get_store(), $this->get_definition(), $hits);
> cache_helper::record_cache_hit($this->get_store(), $this->get_definition(), $hits, $readbytes);
cache_helper::record_cache_miss($this->get_store(), $this->get_definition(), $misses); } return $return; } /** * Delete all of the given keys from the cache. * * @param array $keys The key to delete. * @param bool $recurse When set to true the key will also be deleted from all stacked cache loaders and their stores. * This happens by default and ensure that all the caches are consistent. It is NOT recommended to change this. * @return int The number of items successfully deleted. */ public function delete_many(array $keys, $recurse = true) { $parsedkeys = array_map(array($this, 'parse_key'), $keys); if ($recurse && $this->get_loader() !== false) { // Delete from the bottom of the stack first. $this->get_loader()->delete_many($keys, $recurse); } return $this->get_store()->delete_many($parsedkeys); } /** * Sends several key => value pairs to the cache. * * Using this function comes with potential performance implications. * Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call * the equivalent singular method for each item provided. * This should not deter you from using this function as there is a performance benefit in situations where the cache store * does support it, but you should be aware of this fact. * * <code> * // This code will add four entries to the cache, one for each url. * $cache->set_many(array( * 'main' => 'http://moodle.org', * 'docs' => 'http://docs.moodle.org', * 'tracker' => 'http://tracker.moodle.org', * 'qa' => ''http://qa.moodle.net' * )); * </code> * * @param array $keyvaluearray An array of key => value pairs to send to the cache. * @return int The number of items successfully set. It is up to the developer to check this matches the number of items. * ... if they care that is. */ public function set_many(array $keyvaluearray) { $this->check_tracked_user(); $loader = $this->get_loader(); if ($loader !== false) { // We have a loader available set it there as well. // We have to let the loader do its own parsing of data as it may be unique. $loader->set_many($keyvaluearray); } $data = array(); $definitionid = $this->get_definition()->get_ttl(); $simulatettl = $this->has_a_ttl() && !$this->store_supports_native_ttl(); foreach ($keyvaluearray as $key => $value) { if (is_object($value) && $value instanceof cacheable_object) { $value = new cache_cached_object($value); } else if (!$this->get_store()->supports_dereferencing_objects() && !is_scalar($value)) { // If data is an object it will be a reference. // If data is an array if may contain references. // We want to break references so that the cache cannot be modified outside of itself. // Call the function to unreference it (in the best way possible). $value = $this->unref($value); } if ($simulatettl) { $value = new cache_ttl_wrapper($value, $definitionid); } $data[$key] = array( 'key' => $this->parse_key($key), 'value' => $value ); } $successfullyset = $this->get_store()->set_many($data); if ($this->perfdebug && $successfullyset) {
< cache_helper::record_cache_set($this->get_store(), $this->get_definition(), $successfullyset);
> cache_helper::record_cache_set($this->get_store(), $this->get_definition(), $successfullyset, > $this->get_store()->get_last_io_bytes());
} return $successfullyset; } /** * Purges the cache store, and loader if there is one. * * @return bool True on success, false otherwise */ public function purge() { $this->get_store()->purge(); if ($this->get_loader()) { $this->get_loader()->purge(); } return true; } /** * Test is a cache has a key. * * The use of the has methods is strongly discouraged. In a high load environment the cache may well change between the * test and any subsequent action (get, set, delete etc). * Instead it is recommended to write your code in such a way they it performs the following steps: * <ol> * <li>Attempt to retrieve the information.</li> * <li>Generate the information.</li> * <li>Attempt to set the information</li> * </ol> * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param string|int $key * @param bool $tryloadifpossible If set to true, the cache doesn't contain the key, and there is another cache loader or * data source then the code will try load the key value from the next item in the chain. * @return bool True if the cache has the requested key, false otherwise. */ public function has($key, $tryloadifpossible = false) { $this->check_tracked_user(); $parsedkey = $this->parse_key($key); $store = $this->get_store(); if ($this->has_a_ttl() && !$this->store_supports_native_ttl()) { // The data has a TTL and the store doesn't support it natively. // We must fetch the data and expect a ttl wrapper. $data = $store->get($parsedkey); $has = ($data instanceof cache_ttl_wrapper && !$data->has_expired()); } else if (!$this->store_supports_key_awareness()) { // The store doesn't support key awareness, get the data and check it manually... puke. // Either no TTL is set of the store supports its handling natively. $data = $store->get($parsedkey); $has = ($data !== false); } else { // The store supports key awareness, this is easy! // Either no TTL is set of the store supports its handling natively. /* @var cache_store|cache_is_key_aware $store */ $has = $store->has($parsedkey); } if (!$has && $tryloadifpossible) { $result = null; if ($this->get_loader() !== false) { $result = $this->get_loader()->get($parsedkey); } else if ($this->get_datasource() !== null) { $result = $this->get_datasource()->load_for_cache($key); } $has = ($result !== null); if ($has) { $this->set($key, $result); } } return $has; } /** * Test is a cache has all of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has all of the given keys, false otherwise. */ public function has_all(array $keys) { $this->check_tracked_user(); if (($this->has_a_ttl() && !$this->store_supports_native_ttl()) || !$this->store_supports_key_awareness()) { foreach ($keys as $key) { if (!$this->has($key)) { return false; } } return true; } // The cache must be key aware and if support native ttl if it a ttl is set. /* @var cache_store|cache_is_key_aware $store */ $store = $this->get_store(); return $store->has_all(array_map(array($this, 'parse_key'), $keys)); } /** * Test if a cache has at least one of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has at least one of the given keys */ public function has_any(array $keys) { if (($this->has_a_ttl() && !$this->store_supports_native_ttl()) || !$this->store_supports_key_awareness()) { foreach ($keys as $key) { if ($this->has($key)) { return true; } } return false; } /* @var cache_store|cache_is_key_aware $store */ $store = $this->get_store(); return $store->has_any(array_map(array($this, 'parse_key'), $keys)); } /** * The session loader never uses static acceleration. * Instead it stores things in the static $session variable. Shared between all session loaders. * * @return bool */ protected function use_static_acceleration() { return false; } } /** * An request cache. * * This class is used for request caches returned by the cache::make methods. * * This cache class should never be interacted with directly. Instead you should always use the cache::make methods. * It is technically possible to call those methods through this class however there is no guarantee that you will get an * instance of this class back again. * * @internal don't use me directly. * * @package core * @category cache * @copyright 2012 Sam Hemelryk * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class cache_request extends cache { // This comment appeases code pre-checker ;) ! }