Daniel Ziegenberg
1526 lines
63 KiB
PHP
1526 lines
63 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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namespace core_cache;
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use core\exception\coding_exception;
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use stdClass;
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/**
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* The main cache class.
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*
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* This class if the first class that any end developer will interact with.
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* In order to create an instance of a cache that they can work with they must call one of the static make methods belonging
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* to this class.
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*
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* @package core_cache
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* @category cache
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* @copyright 2012 Sam Hemelryk
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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class cache implements loader_interface {
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/**
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* @var int Constant for cache entries that do not have a version number
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*/
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const VERSION_NONE = -1;
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/**
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* We need a timestamp to use within the cache API.
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* This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with
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* timing issues.
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* @var int
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*/
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protected static $now;
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/**
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* A purge token used to distinguish between multiple cache purges in the same second.
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* This is in the format <microtime>-<random string>.
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*
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* @var string
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*/
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protected static $purgetoken;
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/**
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* The definition used when loading this cache if there was one.
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* @var definition
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*/
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private $definition = false;
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/**
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* The cache store that this loader will make use of.
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* @var store
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*/
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private $store;
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/**
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* The next cache loader in the chain if there is one.
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* If a cache request misses for the store belonging to this loader then the loader
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* stored here will be checked next.
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* If there is a loader here then $datasource must be false.
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* @var loader_interface|false
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*/
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private $loader = false;
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/**
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* The data source to use if we need to load data (because if doesn't exist in the cache store).
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* If there is a data source here then $loader above must be false.
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* @var data_source_interface|false
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*/
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private $datasource = false;
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/**
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* Used to quickly check if the store supports key awareness.
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* This is set when the cache is initialised and is used to speed up processing.
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* @var bool
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*/
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private $supportskeyawareness = null;
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/**
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* Used to quickly check if the store supports ttl natively.
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* This is set when the cache is initialised and is used to speed up processing.
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* @var bool
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*/
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private $supportsnativettl = null;
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/**
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* Gets set to true if the cache is going to be using a static array for acceleration.
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* The array statically caches items used during the lifetime of the request. This greatly speeds up interaction
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* with the cache in areas where it will be repetitively hit for the same information such as with strings.
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* There are several other variables to control how this static acceleration array works.
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* @var bool
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*/
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private $staticacceleration = false;
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/**
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* The static acceleration array.
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* Items will be stored in this cache as they were provided. This ensure there is no unnecessary processing taking place.
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* @var array
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*/
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private $staticaccelerationarray = [];
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/**
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* The number of items in the static acceleration array. Avoids count calls like you wouldn't believe.
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* @var int
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*/
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private $staticaccelerationcount = 0;
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/**
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* An array containing just the keys being used in the static acceleration array.
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* This seems redundant perhaps but is used when managing the size of the static acceleration array.
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* Items are added to the end of the array and the when we need to reduce the size of the cache we use the
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* key that is first on this array.
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* @var array
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*/
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private $staticaccelerationkeys = [];
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/**
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* The maximum size of the static acceleration array.
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*
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* If set to false there is no max size.
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* Caches that make use of static acceleration should seriously consider setting this to something reasonably small, but
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* still large enough to offset repetitive calls.
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*
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* @var int|false
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*/
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private $staticaccelerationsize = false;
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/**
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* Gets set to true during initialisation if the definition is making use of a ttl.
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* Used to speed up processing.
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* @var bool
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*/
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private $hasattl = false;
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/**
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* Gets set to the class name of the store during initialisation. This is used several times in the cache class internally
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* and having it here helps speed up processing.
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* @var strubg
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*/
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protected $storetype = 'unknown';
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/**
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* Gets set to true if we want to collect performance information about the cache API.
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* @var bool
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*/
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protected $perfdebug = false;
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/**
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* Determines if this loader is a sub loader, not the top of the chain.
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* @var bool
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*/
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protected $subloader = false;
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/**
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* Gets set to true if the cache writes (set|delete) must have a manual lock created first.
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* @var bool
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*/
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protected $requirelockingbeforewrite = false;
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/**
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* Gets set to true if the cache's primary store natively supports locking.
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* If it does then we use that, otherwise we need to instantiate a second store to use for locking.
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* @var store|null
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*/
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protected $nativelocking = null;
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/**
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* Creates a new cache instance for a pre-defined definition.
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*
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* @param string $component The component for the definition
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* @param string $area The area for the definition
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* @param array $identifiers Any additional identifiers that should be provided to the definition.
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* @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
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* @return application_cache|session_cache|store
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*/
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public static function make($component, $area, array $identifiers = [], $unused = null) {
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$factory = factory::instance();
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return $factory->create_cache_from_definition($component, $area, $identifiers);
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}
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/**
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* Creates a new cache instance based upon the given params.
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*
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* @param int $mode One of store::MODE_*
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* @param string $component The component this cache relates to.
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* @param string $area The area this cache relates to.
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* @param array $identifiers Any additional identifiers that should be provided to the definition.
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* @param array $options An array of options, available options are:
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* - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
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* - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
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* - staticacceleration : If set to true the cache will hold onto data passing through it.
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* - staticaccelerationsize : The max size for the static acceleration array.
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* @return application_cache|session_cache|request_cache
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*/
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public static function make_from_params($mode, $component, $area, array $identifiers = [], array $options = []) {
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$factory = factory::instance();
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return $factory->create_cache_from_params($mode, $component, $area, $identifiers, $options);
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}
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/**
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* Constructs a new cache instance.
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*
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* You should not call this method from your code, instead you should use the cache::make methods.
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*
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* This method is public so that the factory is able to instantiate cache instances.
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* Ideally we would make this method protected and expose its construction to the factory method internally somehow.
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* The factory class is responsible for this in order to centralise the storage of instances once created. This way if needed
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* we can force a reset of the cache API (used during unit testing).
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*
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* @param definition $definition The definition for the cache instance.
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* @param store $store The store that cache should use.
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* @param loader_interface|data_source_interface $loader The next loader in the chain or the data source if there is one
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* and there are no other loader_interfaces in the chain.
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*/
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public function __construct(definition $definition, store $store, $loader = null) {
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global $CFG;
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$this->definition = $definition;
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$this->store = $store;
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$this->storetype = get_class($store);
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$this->perfdebug = (!empty($CFG->perfdebug) and $CFG->perfdebug > 7);
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if ($loader instanceof loader_interface) {
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$this->set_loader($loader);
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} else if ($loader instanceof data_source_interface) {
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$this->set_data_source($loader);
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}
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$this->definition->generate_definition_hash();
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$this->staticacceleration = $this->definition->use_static_acceleration();
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if ($this->staticacceleration) {
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$this->staticaccelerationsize = $this->definition->get_static_acceleration_size();
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}
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$this->hasattl = ($this->definition->get_ttl() > 0);
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}
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/**
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* Set the loader for this cache.
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*
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* @param loader_interface $loader
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*/
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protected function set_loader(loader_interface $loader): void {
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$this->loader = $loader;
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// Mark the loader as a sub (chained) loader.
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$this->loader->set_is_sub_loader(true);
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}
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/**
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* Set the data source for this cache.
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*
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* @param data_source_interface $datasource
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*/
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protected function set_data_source(data_source_interface $datasource): void {
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$this->datasource = $datasource;
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}
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/**
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* Used to inform the loader of its state as a sub loader, or as the top of the chain.
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*
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* This is important as it ensures that we do not have more than one loader keeping static acceleration data.
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* Subloaders need to be "pure" loaders in the sense that they are used to store and retrieve information from stores or the
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* next loader/data source in the chain.
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* Nothing fancy, nothing flash.
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*
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* @param bool $setting
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*/
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protected function set_is_sub_loader($setting = true) {
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if ($setting) {
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$this->subloader = true;
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// Subloaders should not keep static acceleration data.
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$this->staticacceleration = false;
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$this->staticaccelerationsize = false;
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} else {
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$this->subloader = true;
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$this->staticacceleration = $this->definition->use_static_acceleration();
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if ($this->staticacceleration) {
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$this->staticaccelerationsize = $this->definition->get_static_acceleration_size();
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}
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}
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}
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/**
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* Alters the identifiers that have been provided to the definition.
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*
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* This is an advanced method and should not be used unless really needed.
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* It allows the developer to slightly alter the definition without having to re-establish the cache.
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* It will cause more processing as the definition will need to clear and reprepare some of its properties.
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*
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* @param array $identifiers
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*/
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public function set_identifiers(array $identifiers) {
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if ($this->definition->set_identifiers($identifiers)) {
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// As static acceleration uses input keys and not parsed keys
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// it much be cleared when the identifier set is changed.
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$this->staticaccelerationarray = [];
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if ($this->staticaccelerationsize !== false) {
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$this->staticaccelerationkeys = [];
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$this->staticaccelerationcount = 0;
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}
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}
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}
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/**
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* Process any outstanding invalidation events for the cache we are registering,
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*
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* Identifiers and event invalidation are not compatible with each other at this time.
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* As a result the cache does not need to consider identifiers when working out what to invalidate.
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*/
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protected function handle_invalidation_events() {
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if (!$this->definition->has_invalidation_events()) {
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return;
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}
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// Each cache stores the current 'lastinvalidation' value within the cache itself.
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$lastinvalidation = $this->get('lastinvalidation');
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if ($lastinvalidation === false) {
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// There is currently no value for the lastinvalidation token, therefore the token is not set, and there
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// can be nothing to invalidate.
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// Set the lastinvalidation value to the current purge token and return early.
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$this->set('lastinvalidation', self::get_purge_token());
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return;
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} else if ($lastinvalidation == self::get_purge_token()) {
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// The current purge request has already been fully handled by this cache.
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return;
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}
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/*
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* Now that the whole cache check is complete, we check the meaning of any specific cache invalidation events.
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* These are stored in the core/eventinvalidation cache as an multi-dimensinoal array in the form:
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* [
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* eventname => [
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* keyname => purgetoken,
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* ]
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* ]
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*
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* The 'keyname' value is used to delete a specific key in the cache.
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* If the keyname is set to the special value 'purged', then the whole cache is purged instead.
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*
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* The 'purgetoken' is the token that this key was last purged.
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* a) If the purgetoken matches the last invalidation, then the key/cache is not purged.
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* b) If the purgetoken is newer than the last invalidation, then the key/cache is not purged.
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* c) If the purge token is older than the last invalidation, or it has a different token component, then the
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* cache is purged.
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*
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* Option b should not happen under normal operation, but may happen in race condition whereby a long-running
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* request's cache is cleared in another process during that request, and prior to that long-running request
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* creating the cache. In such a condition, it would be incorrect to clear that cache.
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*/
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$cache = self::make('core', 'eventinvalidation');
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$events = $cache->get_many($this->definition->get_invalidation_events());
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$todelete = [];
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$purgeall = false;
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// Iterate the returned data for the events.
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foreach ($events as $event => $keys) {
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if ($keys === false) {
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// No data to be invalidated yet.
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continue;
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}
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// Look at each key and check the timestamp.
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foreach ($keys as $key => $purgetoken) {
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// If the timestamp of the event is more than or equal to the last invalidation (happened between the last
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// invalidation and now), then we need to invaliate the key.
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if (self::compare_purge_tokens($purgetoken, $lastinvalidation) > 0) {
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if ($key === 'purged') {
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$purgeall = true;
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break;
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} else {
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$todelete[] = $key;
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}
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}
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}
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}
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if ($purgeall) {
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$this->purge();
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} else if (!empty($todelete)) {
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$todelete = array_unique($todelete);
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$this->delete_many($todelete);
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}
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// Set the time of the last invalidation.
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if ($purgeall || !empty($todelete)) {
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$this->set('lastinvalidation', self::get_purge_token(true));
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}
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}
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/**
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* Retrieves the value for the given key from the cache.
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*
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* @param string|int $key The key for the data being requested.
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* It can be any structure although using a scalar string or int is recommended in the interests of performance.
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* In advanced cases an array may be useful such as in situations requiring the multi-key functionality.
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* @param int $strictness One of IGNORE_MISSING | MUST_EXIST
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* @return mixed|false The data from the cache or false if the key did not exist within the cache.
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* @throws coding_exception
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*/
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public function get($key, $strictness = IGNORE_MISSING) {
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return $this->get_implementation($key, self::VERSION_NONE, $strictness);
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}
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/**
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* Retrieves the value and actual version for the given key, with at least the required version.
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*
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* If there is no value for the key, or there is a value but it doesn't have the required
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* version, then this function will return null (or throw an exception if you set strictness
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* to MUST_EXIST).
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*
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* This function can be used to make it easier to support localisable caches (where the cache
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* could be stored on a local server as well as a shared cache). Specifying the version means
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* that it will automatically retrieve the correct version if available, either from the local
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* server or [if that has an older version] from the shared server.
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*
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* If the cached version is newer than specified version, it will be returned regardless. For
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* example, if you request version 4, but the locally cached version is 5, it will be returned.
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* If you request version 6, and the locally cached version is 5, then the system will look in
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* higher-level caches (if any); if there still isn't a version 6 or greater, it will return
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* null.
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*
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* You must use this function if you use set_versioned.
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*
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* @param string|int $key The key for the data being requested.
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* @param int $requiredversion Minimum required version of the data
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* @param int $strictness One of IGNORE_MISSING or MUST_EXIST.
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* @param mixed $actualversion If specified, will be set to the actual version number retrieved
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* @return mixed Data from the cache, or false if the key did not exist or was too old
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* @throws \coding_exception If you call get_versioned on a non-versioned cache key
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*/
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public function get_versioned($key, int $requiredversion, int $strictness = IGNORE_MISSING, &$actualversion = null) {
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return $this->get_implementation($key, $requiredversion, $strictness, $actualversion);
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}
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/**
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* Checks returned data to see if it matches the specified version number.
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*
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* For versioned data, this returns the version_wrapper object (or false). For other
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* data, it returns the actual data (or false).
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*
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* @param mixed $result Result data
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* @param int $requiredversion Required version number or VERSION_NONE if there must be no version
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* @return bool True if version is current, false if not (or if result is false)
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* @throws \coding_exception If unexpected type of data (versioned vs non-versioned) is found
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*/
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protected static function check_version($result, int $requiredversion): bool {
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if ($requiredversion === self::VERSION_NONE) {
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if ($result instanceof \core_cache\version_wrapper) {
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throw new \coding_exception('Unexpectedly found versioned cache entry');
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} else {
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// No version checks, so version is always correct.
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return true;
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}
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} else {
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// If there's no result, obviously it doesn't meet the required version.
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if (!helper::result_found($result)) {
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return false;
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}
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if (!($result instanceof \core_cache\version_wrapper)) {
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throw new \coding_exception('Unexpectedly found non-versioned cache entry');
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}
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// If the result doesn't match the required version tag, return false.
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if ($result->version < $requiredversion) {
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return false;
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}
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// The version meets the requirement.
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return true;
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}
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}
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/**
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* Retrieves the value for the given key from the cache.
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|
*
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* @param string|int $key The key for the data being requested.
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* It can be any structure although using a scalar string or int is recommended in the interests of performance.
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* In advanced cases an array may be useful such as in situations requiring the multi-key functionality.
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* @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE
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* @param int $strictness One of IGNORE_MISSING | MUST_EXIST
|
|
* @param mixed $actualversion If specified, will be set to the actual version number retrieved
|
|
* @return mixed|false The data from the cache or false if the key did not exist within the cache.
|
|
* @throws coding_exception
|
|
*/
|
|
protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {
|
|
// 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) {
|
|
$result = $this->static_acceleration_get($key);
|
|
if (helper::result_found($result) && self::check_version($result, $requiredversion)) {
|
|
if ($requiredversion === self::VERSION_NONE) {
|
|
return $result;
|
|
} else {
|
|
$actualversion = $result->version;
|
|
return $result->data;
|
|
}
|
|
}
|
|
}
|
|
|
|
// 2. Parse the key.
|
|
$parsedkey = $this->parse_key($key);
|
|
|
|
// 3. Get it from the store. Obviously wasn't in the static acceleration array.
|
|
$result = $this->store->get($parsedkey);
|
|
if (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 (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 ttl_wrapper) {
|
|
if ($ttlconsider->has_expired()) {
|
|
$this->store->delete($parsedkey);
|
|
$result = false;
|
|
} else if ($requiredversion === self::VERSION_NONE) {
|
|
// Use the data inside the TTL wrapper as the result.
|
|
$result = $ttlconsider->data;
|
|
} else {
|
|
// Put the data from the TTL wrapper directly inside the version wrapper.
|
|
$result->data = $ttlconsider->data;
|
|
}
|
|
}
|
|
if ($usesstaticacceleration) {
|
|
$this->static_acceleration_set($key, $result);
|
|
}
|
|
// Remove version wrapper if necessary.
|
|
if ($requiredversion !== self::VERSION_NONE) {
|
|
$actualversion = $result->version;
|
|
$result = $result->data;
|
|
}
|
|
if ($result instanceof cached_object) {
|
|
$result = $result->restore_object();
|
|
}
|
|
}
|
|
|
|
// 4. Load if from the loader/datasource if we don't already have it.
|
|
$setaftervalidation = false;
|
|
if (!helper::result_found($result)) {
|
|
if ($this->perfdebug) {
|
|
helper::record_cache_miss($this->store, $this->definition);
|
|
}
|
|
if ($this->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.
|
|
if ($requiredversion === self::VERSION_NONE) {
|
|
$result = $this->loader->get($key);
|
|
} else {
|
|
$result = $this->loader->get_versioned($key, $requiredversion, IGNORE_MISSING, $actualversion);
|
|
}
|
|
} else if ($this->datasource !== false) {
|
|
if ($requiredversion === self::VERSION_NONE) {
|
|
$result = $this->datasource->load_for_cache($key);
|
|
} else {
|
|
if (!$this->datasource instanceof versionable_data_source_interface) {
|
|
throw new \coding_exception('Data source is not versionable');
|
|
}
|
|
$result = $this->datasource->load_for_cache_versioned($key, $requiredversion, $actualversion);
|
|
if ($result && $actualversion < $requiredversion) {
|
|
throw new \coding_exception('Data source returned outdated version');
|
|
}
|
|
}
|
|
}
|
|
$setaftervalidation = (helper::result_found($result));
|
|
} else if ($this->perfdebug) {
|
|
$readbytes = $this->store->get_last_io_bytes();
|
|
helper::record_cache_hit($this->store, $this->definition, 1, $readbytes);
|
|
}
|
|
// 5. Validate strictness.
|
|
if ($strictness === MUST_EXIST && !helper::result_found($result)) {
|
|
throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.');
|
|
}
|
|
// 6. Set it to the store if we got it from the loader/datasource. Only set to this direct
|
|
// store; parent method will have set it to all stores if needed.
|
|
if ($setaftervalidation) {
|
|
$lock = false;
|
|
try {
|
|
// Only try to acquire a lock for this cache if we do not already have one.
|
|
if (!empty($this->requirelockingbeforewrite) && !$this->check_lock_state($key)) {
|
|
$this->acquire_lock($key);
|
|
$lock = true;
|
|
}
|
|
if ($requiredversion === self::VERSION_NONE) {
|
|
$this->set_implementation($key, self::VERSION_NONE, $result, false);
|
|
} else {
|
|
$this->set_implementation($key, $actualversion, $result, false);
|
|
}
|
|
} finally {
|
|
if ($lock) {
|
|
$this->release_lock($key);
|
|
}
|
|
}
|
|
}
|
|
// 7. 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 (!$this->store->supports_dereferencing_objects() && !is_scalar($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;
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
|
|
$keysparsed = [];
|
|
$parsedkeys = [];
|
|
$resultpersist = [];
|
|
$resultstore = [];
|
|
$keystofind = [];
|
|
$readbytes = store::IO_BYTES_NOT_SUPPORTED;
|
|
|
|
// First up check the persist cache for each key.
|
|
$isusingpersist = $this->use_static_acceleration();
|
|
foreach ($keys as $key) {
|
|
$pkey = $this->parse_key($key);
|
|
if (is_array($pkey)) {
|
|
$pkey = $pkey['key'];
|
|
}
|
|
$keysparsed[$key] = $pkey;
|
|
$parsedkeys[$pkey] = $key;
|
|
$keystofind[$pkey] = $key;
|
|
if ($isusingpersist) {
|
|
$value = $this->static_acceleration_get($key);
|
|
if ($value !== false) {
|
|
$resultpersist[$pkey] = $value;
|
|
unset($keystofind[$pkey]);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Next assuming we didn't find all of the keys in the persist cache try loading them from the store.
|
|
if (count($keystofind)) {
|
|
$resultstore = $this->store->get_many(array_keys($keystofind));
|
|
if ($this->perfdebug) {
|
|
$readbytes = $this->store->get_last_io_bytes();
|
|
}
|
|
// Process each item in the result to "unwrap" it.
|
|
foreach ($resultstore as $key => $value) {
|
|
if ($value instanceof ttl_wrapper) {
|
|
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 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) {
|
|
$missingkeys = [];
|
|
foreach ($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;
|
|
$lock = false;
|
|
try {
|
|
if (!empty($this->requirelockingbeforewrite)) {
|
|
$this->acquire_lock($key);
|
|
$lock = true;
|
|
}
|
|
if ($value !== false) {
|
|
$this->set($key, $value);
|
|
}
|
|
} finally {
|
|
if ($lock) {
|
|
$this->release_lock($key);
|
|
}
|
|
}
|
|
}
|
|
unset($resultmissing);
|
|
}
|
|
unset($missingkeys);
|
|
}
|
|
|
|
// Create an array with the original keys and the found values. This will be what we return.
|
|
$fullresult = [];
|
|
foreach ($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 {
|
|
$hits++;
|
|
}
|
|
}
|
|
helper::record_cache_hit($this->store, $this->definition, $hits, $readbytes);
|
|
helper::record_cache_miss($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) {
|
|
return $this->set_implementation($key, self::VERSION_NONE, $data);
|
|
}
|
|
|
|
/**
|
|
* 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_interface) {
|
|
$data = new cached_object($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 ($usestaticacceleration) {
|
|
// Static acceleration cache should include the cache version wrapper, but not TTL.
|
|
if ($version === self::VERSION_NONE) {
|
|
$this->static_acceleration_set($key, $data);
|
|
} else {
|
|
$this->static_acceleration_set($key, new \core_cache\version_wrapper($data, $version));
|
|
}
|
|
}
|
|
|
|
if ($this->has_a_ttl() && !$this->store_supports_native_ttl()) {
|
|
$data = new ttl_wrapper($data, $this->definition->get_ttl());
|
|
}
|
|
$parsedkey = $this->parse_key($key);
|
|
|
|
if ($version !== self::VERSION_NONE) {
|
|
$data = new \core_cache\version_wrapper($data, $version);
|
|
}
|
|
|
|
$success = $this->store->set($parsedkey, $data);
|
|
if ($this->perfdebug) {
|
|
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_interface) {
|
|
$value = new cached_object($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) {
|
|
$value = new ttl_wrapper($value, $this->definition->get_ttl());
|
|
}
|
|
$data[$key] = [
|
|
'key' => $this->parse_key($key),
|
|
'value' => $value,
|
|
];
|
|
}
|
|
$successfullyset = $this->store->set_many($data);
|
|
if ($this->perfdebug && $successfullyset) {
|
|
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 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;
|
|
}
|
|
$parsedkeys = array_map([$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;
|
|
}
|
|
}
|
|
}
|
|
$parsedkeys = array_map([$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);
|
|
}
|
|
$parsedkeys = array_map([$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 $result;
|
|
}
|
|
// If not we need to generate a hash and to for that we use the helper.
|
|
return helper::hash_key($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 definition
|
|
*/
|
|
protected function get_definition() {
|
|
return $this->definition;
|
|
}
|
|
|
|
/**
|
|
* Returns the cache store
|
|
*
|
|
* @return 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 data_source_interface|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 key_aware_cache_interface);
|
|
}
|
|
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 lockable_cache_interface);
|
|
}
|
|
return $this->nativelocking;
|
|
}
|
|
|
|
/**
|
|
* Returns true if this cache is making use of the static acceleration array.
|
|
*
|
|
* @return bool
|
|
*/
|
|
protected function use_static_acceleration() {
|
|
return $this->staticacceleration;
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
/**
|
|
* 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 cached_object) {
|
|
$result = $data->restore_object();
|
|
} else if ($this->staticaccelerationarray[$key]['serialized']) {
|
|
$result = unserialize($data);
|
|
} else {
|
|
$result = $data;
|
|
}
|
|
}
|
|
if (helper::result_found($result)) {
|
|
if ($this->perfdebug) {
|
|
helper::record_cache_hit(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) {
|
|
helper::record_cache_miss(store::STATIC_ACCEL, $this->definition);
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 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;
|
|
}
|
|
|
|
/**
|
|
* 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() {
|
|
$this->staticaccelerationarray = [];
|
|
if ($this->staticaccelerationsize !== false) {
|
|
$this->staticaccelerationkeys = [];
|
|
$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 === $tokenb) {
|
|
// There is an exact match.
|
|
return 0;
|
|
}
|
|
|
|
// The token for when the cache was last invalidated.
|
|
[$atime] = explode('-', "{$tokena}-", 2);
|
|
|
|
// The token for this cache.
|
|
[$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() {
|
|
}
|
|
}
|
|
|
|
// Alias this class to the old name.
|
|
// This file will be autoloaded by the legacyclasses autoload system.
|
|
// In future all uses of this class will be corrected and the legacy references will be removed.
|
|
class_alias(cache::class, \cache::class);
|