mirror of
https://github.com/moodle/moodle.git
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2049 lines
82 KiB
PHP
2049 lines
82 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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/**
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* Cache loaders
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*
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* This file is part of Moodle's cache API, affectionately called MUC.
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* It contains the components that are required in order to use caching.
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*
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* @package core
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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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defined('MOODLE_INTERNAL') || die();
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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
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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 cache_loader {
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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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* The definition used when loading this cache if there was one.
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* @var cache_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 cache_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 cache_loader|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 cache_data_source|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 the build in static "persist" cache.
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* The persist cache 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 persist cache works.
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* @var bool
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*/
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private $persist = false;
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/**
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* The persist cache itself.
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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 $persistcache = array();
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/**
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* The number of items in the persist cache. Avoids count calls like you wouldn't believe.
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* @var int
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*/
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private $persistcount = 0;
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/**
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* An array containing just the keys being used in the persist cache.
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* This seems redundant perhaps but is used when managing the size of the persist cache.
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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 $persistkeys = array();
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/**
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* The maximum size of the persist cache. If set to false there is no max size.
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* Caches that make use of the persist cache 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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* @var int|false
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*/
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private $persistmaxsize = 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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* 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 $aggregate Super advanced feature. More docs later.
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* @return cache_application|cache_session|cache_store
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*/
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public static function make($component, $area, array $identifiers = array(), $aggregate = null) {
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$factory = cache_factory::instance();
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return $factory->create_cache_from_definition($component, $area, $identifiers, $aggregate);
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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 cache_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 $options An array of options, available options are:
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* - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
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* - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
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* - persistent : If set to true the cache will persist construction requests.
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* @return cache_application|cache_session|cache_store
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*/
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public static function make_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {
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$factory = cache_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 cache_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 cache_definition $definition The definition for the cache instance.
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* @param cache_store $store The store that cache should use.
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* @param cache_loader|cache_data_source $loader The next loader in the chain or the data source if there is one and there
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* are no other cache_loaders in the chain.
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*/
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public function __construct(cache_definition $definition, cache_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($CFG->perfdebug);
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if ($loader instanceof cache_loader) {
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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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} else if ($loader instanceof cache_data_source) {
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$this->datasource = $loader;
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}
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$this->definition->generate_definition_hash();
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$this->persist = $this->definition->should_be_persistent();
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if ($this->persist) {
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$this->persistmaxsize = $this->definition->get_persistent_max_size();
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}
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$this->hasattl = ($this->definition->get_ttl() > 0);
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}
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/**
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* 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 persistent 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 persistent data.
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$this->persist = false;
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$this->persistmaxsize = false;
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} else {
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$this->subloader = true;
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$this->persist = $this->definition->should_be_persistent();
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if ($this->persist) {
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$this->persistmaxsize = $this->definition->get_persistent_max_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 $identifiers) {
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$this->definition->set_identifiers($identifiers);
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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 $strictness One of IGNORE_MISSING | MUST_EXIST
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* @return mixed|false The data from the cache or false if the key did not exist within the cache.
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* @throws moodle_exception
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*/
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public function get($key, $strictness = IGNORE_MISSING) {
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// 1. Parse the key.
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$parsedkey = $this->parse_key($key);
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// 2. Get it from the persist cache if we can (only when persist is enabled and it has already been requested/set).
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$result = false;
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if ($this->is_using_persist_cache()) {
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$result = $this->get_from_persist_cache($parsedkey);
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}
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if ($result !== false) {
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if (!is_scalar($result)) {
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// If data is an object it will be a reference.
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// If data is an array if may contain references.
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// We want to break references so that the cache cannot be modified outside of itself.
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// Call the function to unreference it (in the best way possible).
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$result = $this->unref($result);
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}
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return $result;
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}
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// 3. Get it from the store. Obviously wasn't in the persist cache.
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$result = $this->store->get($parsedkey);
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if ($result !== false) {
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if ($result instanceof cache_ttl_wrapper) {
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if ($result->has_expired()) {
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$this->store->delete($parsedkey);
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$result = false;
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} else {
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$result = $result->data;
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}
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}
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if ($result instanceof cache_cached_object) {
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$result = $result->restore_object();
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}
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if ($this->is_using_persist_cache()) {
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$this->set_in_persist_cache($parsedkey, $result);
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}
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}
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// 4. Load if from the loader/datasource if we don't already have it.
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$setaftervalidation = false;
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if ($result === false) {
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if ($this->perfdebug) {
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cache_helper::record_cache_miss($this->storetype, $this->definition->get_id());
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}
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if ($this->loader !== false) {
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// We must pass the original (unparsed) key to the next loader in the chain.
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// The next loader will parse the key as it sees fit. It may be parsed differently
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// depending upon the capabilities of the store associated with the loader.
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$result = $this->loader->get($key);
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} else if ($this->datasource !== false) {
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$result = $this->datasource->load_for_cache($key);
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}
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$setaftervalidation = ($result !== false);
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} else if ($this->perfdebug) {
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cache_helper::record_cache_hit($this->storetype, $this->definition->get_id());
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}
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// 5. Validate strictness.
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if ($strictness === MUST_EXIST && $result === false) {
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throw new moodle_exception('Requested key did not exist in any cache stores and could not be loaded.');
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}
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// 6. Set it to the store if we got it from the loader/datasource.
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if ($setaftervalidation) {
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$this->set($key, $result);
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}
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// 7. Make sure we don't pass back anything that could be a reference.
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// We don't want people modifying the data in the cache.
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if (!is_scalar($result)) {
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// If data is an object it will be a reference.
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// If data is an array if may contain references.
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// We want to break references so that the cache cannot be modified outside of itself.
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// Call the function to unreference it (in the best way possible).
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$result = $this->unref($result);
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}
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return $result;
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}
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/**
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* Retrieves an array of values for an array of keys.
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*
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* Using this function comes with potential performance implications.
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* Not all cache stores will support get_many/set_many operations and in order to replicate this functionality will call
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* the equivalent singular method for each item provided.
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* This should not deter you from using this function as there is a performance benefit in situations where the cache store
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* does support it, but you should be aware of this fact.
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*
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* @param array $keys The keys of the data being requested.
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* Each key 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 or MUST_EXIST.
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* @return array An array of key value pairs for the items that could be retrieved from the cache.
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* If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown.
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* Otherwise any key that did not exist will have a data value of false within the results.
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* @throws moodle_exception
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*/
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public function get_many(array $keys, $strictness = IGNORE_MISSING) {
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$keysparsed = array();
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$parsedkeys = array();
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$resultpersist = array();
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$resultstore = array();
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$keystofind = array();
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// First up check the persist cache for each key.
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$isusingpersist = $this->is_using_persist_cache();
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foreach ($keys as $key) {
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$pkey = $this->parse_key($key);
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$keysparsed[$key] = $pkey;
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$parsedkeys[$pkey] = $key;
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$keystofind[$pkey] = $key;
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if ($isusingpersist) {
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$value = $this->get_from_persist_cache($pkey);
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if ($value !== false) {
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$resultpersist[$pkey] = $value;
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unset($keystofind[$pkey]);
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}
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}
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}
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// Next assuming we didn't find all of the keys in the persist cache try loading them from the store.
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if (count($keystofind)) {
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$resultstore = $this->store->get_many(array_keys($keystofind));
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// Process each item in the result to "unwrap" it.
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foreach ($resultstore as $key => $value) {
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if ($value instanceof cache_ttl_wrapper) {
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if ($value->has_expired()) {
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$value = false;
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} else {
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$value = $value->data;
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}
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}
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if ($value instanceof cache_cached_object) {
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$value = $value->restore_object();
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}
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$resultstore[$key] = $value;
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}
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}
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// Merge the result from the persis cache with the results from the store load.
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$result = $resultpersist + $resultstore;
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unset($resultpersist);
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unset($resultstore);
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// Next we need to find any missing values and load them from the loader/datasource next in the chain.
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$usingloader = ($this->loader !== false);
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$usingsource = (!$usingloader && ($this->datasource !== false));
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if ($usingloader || $usingsource) {
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$missingkeys = array();
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foreach ($result as $key => $value) {
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if ($value === false) {
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$missingkeys[] = ($usingloader) ? $key : $parsedkeys[$key];
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}
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}
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if (!empty($missingkeys)) {
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if ($usingloader) {
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$resultmissing = $this->loader->get_many($missingkeys);
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} else {
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$resultmissing = $this->datasource->load_many_for_cache($missingkeys);
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}
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foreach ($resultmissing as $key => $value) {
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$pkey = ($usingloader) ? $key : $keysparsed[$key];
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$realkey = ($usingloader) ? $parsedkeys[$key] : $key;
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$result[$pkey] = $value;
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if ($value !== false) {
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$this->set($realkey, $value);
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}
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}
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unset($resultmissing);
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}
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unset($missingkeys);
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}
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// Create an array with the original keys and the found values. This will be what we return.
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$fullresult = array();
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foreach ($result as $key => $value) {
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$fullresult[$parsedkeys[$key]] = $value;
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}
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unset($result);
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// Final step is to check strictness.
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if ($strictness === MUST_EXIST) {
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foreach ($keys as $key) {
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if (!array_key_exists($key, $fullresult)) {
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throw new moodle_exception('Not all the requested keys existed within the cache stores.');
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}
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}
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}
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// Return the result. Phew!
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return $fullresult;
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}
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/**
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* Sends a key => value pair to the cache.
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*
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* <code>
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* // This code will add four entries to the cache, one for each url.
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* $cache->set('main', 'http://moodle.org');
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* $cache->set('docs', 'http://docs.moodle.org');
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* $cache->set('tracker', 'http://tracker.moodle.org');
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* $cache->set('qa', 'http://qa.moodle.net');
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* </code>
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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 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->storetype, $this->definition->get_id());
|
|
}
|
|
if (is_object($data) && $data instanceof cacheable_object) {
|
|
$data = new cache_cached_object($data);
|
|
} else if (!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 ($this->has_a_ttl() && !$this->store_supports_native_ttl()) {
|
|
$data = new cache_ttl_wrapper($data, $this->definition->get_ttl());
|
|
}
|
|
$parsedkey = $this->parse_key($key);
|
|
if ($this->is_using_persist_cache()) {
|
|
$this->set_in_persist_cache($parsedkey, $data);
|
|
}
|
|
return $this->store->set($parsedkey, $data);
|
|
}
|
|
|
|
/**
|
|
* Removes references where required.
|
|
*
|
|
* @param stdClass|array $data
|
|
*/
|
|
protected function unref($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) {
|
|
$data = array();
|
|
$simulatettl = $this->has_a_ttl() && !$this->store_supports_native_ttl();
|
|
$usepersistcache = $this->is_using_persist_cache();
|
|
foreach ($keyvaluearray as $key => $value) {
|
|
if (is_object($value) && $value instanceof cacheable_object) {
|
|
$value = new cache_cached_object($value);
|
|
} else 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);
|
|
}
|
|
if ($simulatettl) {
|
|
$value = new cache_ttl_wrapper($value, $this->definition->get_ttl());
|
|
}
|
|
$data[$key] = array(
|
|
'key' => $this->parse_key($key),
|
|
'value' => $value
|
|
);
|
|
if ($usepersistcache) {
|
|
$this->set_in_persist_cache($data[$key]['key'], $value);
|
|
}
|
|
}
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_set($this->storetype, $this->definition->get_id());
|
|
}
|
|
return $this->store->set_many($data);
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
$parsedkey = $this->parse_key($key);
|
|
if ($this->is_in_persist_cache($parsedkey)) {
|
|
// Hoorah, that was easy. It exists in the persist cache so we definitely have it.
|
|
return true;
|
|
}
|
|
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->is_using_persist_cache()) {
|
|
$parsedkeys = array();
|
|
foreach ($keys as $id => $key) {
|
|
$parsedkey = $this->parse_key($key);
|
|
if ($this->is_in_persist_cache($parsedkey)) {
|
|
return true;
|
|
}
|
|
$parsedkeys[] = $parsedkey;
|
|
}
|
|
} else {
|
|
$parsedkeys = array_map(array($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) {
|
|
$parsedkey = $this->parse_key($key);
|
|
$this->delete_from_persist_cache($parsedkey);
|
|
if ($recurse && $this->loader !== false) {
|
|
// Delete from the bottom of the stack first.
|
|
$this->loader->delete($key, $recurse);
|
|
}
|
|
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) {
|
|
$parsedkeys = array_map(array($this, 'parse_key'), $keys);
|
|
if ($this->is_using_persist_cache()) {
|
|
foreach ($parsedkeys as $parsedkey) {
|
|
$this->delete_from_persist_cache($parsedkey);
|
|
}
|
|
}
|
|
if ($recurse && $this->loader !== false) {
|
|
// Delete from the bottom of the stack first.
|
|
$this->loader->delete_many($keys, $recurse);
|
|
}
|
|
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 persist cache.
|
|
$this->persistcache = array();
|
|
// 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 2.4.4
|
|
* @return cache_loader|false
|
|
*/
|
|
protected function get_loader() {
|
|
return $this->loader;
|
|
}
|
|
|
|
/**
|
|
* Returns the data source associated with this cache.
|
|
*
|
|
* @since 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;
|
|
}
|
|
|
|
/**
|
|
* Returns true if this cache is making use of the persist cache.
|
|
*
|
|
* @return bool
|
|
*/
|
|
protected function is_using_persist_cache() {
|
|
return $this->persist;
|
|
}
|
|
|
|
/**
|
|
* Returns true if the requested key exists within the persist cache.
|
|
*
|
|
* @param string $key The parsed key
|
|
* @return bool
|
|
*/
|
|
protected function is_in_persist_cache($key) {
|
|
// This method of checking if an array was supplied is faster than is_array.
|
|
if ($key === (array)$key) {
|
|
$key = $key['key'];
|
|
}
|
|
// This could be written as a single line, however it has been split because the ttl check is faster than the instanceof
|
|
// and has_expired calls.
|
|
if (!$this->persist || !array_key_exists($key, $this->persistcache)) {
|
|
return false;
|
|
}
|
|
if ($this->has_a_ttl() && $this->store_supports_native_ttl()) {
|
|
return !($this->persistcache[$key] instanceof cache_ttl_wrapper && $this->persistcache[$key]->has_expired());
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Returns the item from the persist cache if it exists there.
|
|
*
|
|
* @param string $key The parsed key
|
|
* @return mixed|false The data from the persist cache or false if it wasn't there.
|
|
*/
|
|
protected function get_from_persist_cache($key) {
|
|
// This method of checking if an array was supplied is faster than is_array.
|
|
if ($key === (array)$key) {
|
|
$key = $key['key'];
|
|
}
|
|
// This isset check is faster than array_key_exists but will return false
|
|
// for null values, meaning null values will come from backing store not
|
|
// the persist cache. We think this okay because null usage should be
|
|
// very rare (see comment in MDL-39472).
|
|
if (!$this->persist || !isset($this->persistcache[$key])) {
|
|
$result = false;
|
|
} else {
|
|
$data = $this->persistcache[$key];
|
|
if (!$this->has_a_ttl() || !$data instanceof cache_ttl_wrapper) {
|
|
if ($data instanceof cache_cached_object) {
|
|
$data = $data->restore_object();
|
|
}
|
|
$result = $data;
|
|
} else if ($data->has_expired()) {
|
|
$this->delete_from_persist_cache($key);
|
|
$result = false;
|
|
} else {
|
|
if ($data instanceof cache_cached_object) {
|
|
$data = $data->restore_object();
|
|
}
|
|
$result = $data->data;
|
|
}
|
|
}
|
|
if ($result) {
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_hit('** static persist **', $this->definition->get_id());
|
|
}
|
|
if ($this->persistmaxsize > 1 && $this->persistcount > 1) {
|
|
// Check to see if this is the last item on the persist keys array.
|
|
if (end($this->persistkeys) !== $key) {
|
|
// It isn't the last item.
|
|
// Move the item to the end of the array so that it is last to be removed.
|
|
unset($this->persistkeys[$key]);
|
|
$this->persistkeys[$key] = $key;
|
|
}
|
|
}
|
|
return $result;
|
|
} else {
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_miss('** static persist **', $this->definition->get_id());
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Sets a key value pair into the persist cache.
|
|
*
|
|
* @param string $key The parsed key
|
|
* @param mixed $data
|
|
* @return bool
|
|
*/
|
|
protected function set_in_persist_cache($key, $data) {
|
|
// This method of checking if an array was supplied is faster than is_array.
|
|
if ($key === (array)$key) {
|
|
$key = $key['key'];
|
|
}
|
|
$this->persistcache[$key] = $data;
|
|
if ($this->persistmaxsize !== false) {
|
|
$this->persistcount++;
|
|
$this->persistkeys[$key] = $key;
|
|
if ($this->persistcount > $this->persistmaxsize) {
|
|
$dropkey = array_shift($this->persistkeys);
|
|
unset($this->persistcache[$dropkey]);
|
|
$this->persistcount--;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Deletes an item from the persist cache.
|
|
*
|
|
* @param string|int $key As given to get|set|delete
|
|
* @return bool True on success, false otherwise.
|
|
*/
|
|
protected function delete_from_persist_cache($key) {
|
|
unset($this->persistcache[$key]);
|
|
if ($this->persistmaxsize !== false) {
|
|
$dropkey = array_search($key, $this->persistkeys);
|
|
if ($dropkey) {
|
|
unset($this->persistkeys[$dropkey]);
|
|
$this->persistcount--;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Returns the timestamp from the first request for the time from the cache API.
|
|
*
|
|
* This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with
|
|
* timing issues.
|
|
*
|
|
* @return int
|
|
*/
|
|
public static function now() {
|
|
if (self::$now === null) {
|
|
self::$now = time();
|
|
}
|
|
return self::$now;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 a cache_store to use for locking if the caches primary store doesn't support locking natively.
|
|
* @var cache_lock_interface
|
|
*/
|
|
protected $cachelockinstance;
|
|
|
|
/**
|
|
* Overrides the cache construct method.
|
|
*
|
|
* 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, $loader = null) {
|
|
parent::__construct($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 = $definition->require_locking_write();
|
|
}
|
|
|
|
if ($definition->has_invalidation_events()) {
|
|
$lastinvalidation = $this->get('lastinvalidation');
|
|
if ($lastinvalidation === false) {
|
|
// This is a new session, there won't be anything to invalidate. Set the time of the last invalidation and
|
|
// move on.
|
|
$this->set('lastinvalidation', cache::now());
|
|
return;
|
|
} else if ($lastinvalidation == cache::now()) {
|
|
// We've already invalidated during this request.
|
|
return;
|
|
}
|
|
|
|
// Get the event invalidation cache.
|
|
$cache = cache::make('core', 'eventinvalidation');
|
|
$events = $cache->get_many($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 => $timestamp) {
|
|
// If the timestamp of the event is more than or equal to the last invalidation (happened between the last
|
|
// invalidation and now)then we need to invaliate the key.
|
|
if ($timestamp >= $lastinvalidation) {
|
|
if ($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.
|
|
$this->set('lastinvalidation', cache::now());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
if ($this->nativelocking) {
|
|
return $this->get_store()->acquire_lock($key, $this->get_identifier());
|
|
} else {
|
|
$this->ensure_cachelock_available();
|
|
return $this->cachelockinstance->lock($key, $this->get_identifier());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
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);
|
|
if ($this->nativelocking) {
|
|
return $this->get_store()->release_lock($key, $this->get_identifier());
|
|
} else {
|
|
$this->ensure_cachelock_available();
|
|
return $this->cachelockinstance->unlock($key, $this->get_identifier());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Ensure that the dedicated lock store is ready to go.
|
|
*
|
|
* This should only happen if the cache store doesn't natively support it.
|
|
*/
|
|
protected function ensure_cachelock_available() {
|
|
if ($this->cachelockinstance === null) {
|
|
$this->cachelockinstance = cache_helper::get_cachelock_for_store($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 mixed $data The data to set against the key.
|
|
* @return bool True on success, false otherwise.
|
|
*/
|
|
public function set($key, $data) {
|
|
if ($this->requirelockingwrite && !$this->acquire_lock($key)) {
|
|
return false;
|
|
}
|
|
$result = parent::set($key, $data);
|
|
if ($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->requirelockingwrite) {
|
|
$locks = array();
|
|
foreach ($keyvaluearray as $id => $pair) {
|
|
$key = $pair['key'];
|
|
if ($this->acquire_lock($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 $strictness One of IGNORE_MISSING | MUST_EXIST
|
|
* @return mixed|false The data from the cache or false if the key did not exist within the cache.
|
|
* @throws moodle_exception
|
|
*/
|
|
public function get($key, $strictness = IGNORE_MISSING) {
|
|
if ($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);
|
|
}
|
|
|
|
/**
|
|
* 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 moodle_exception
|
|
*/
|
|
public function get_many(array $keys, $strictness = IGNORE_MISSING) {
|
|
if ($this->requirelockingread) {
|
|
foreach ($keys as $id => $key) {
|
|
$lock =$this->acquire_lock($key);
|
|
if (!$lock) {
|
|
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);
|
|
}
|
|
|
|
/**
|
|
* 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 be persistent.
|
|
* Because of this we don't ever use the persist cache and instead a session array
|
|
* containing all of the data is maintained by this object.
|
|
* 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.
|
|
*
|
|
* @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_';
|
|
|
|
/**
|
|
* 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
|
|
* @return void
|
|
*/
|
|
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;
|
|
parent::__construct($definition, $store, $loader);
|
|
if ($definition->has_invalidation_events()) {
|
|
$lastinvalidation = $this->get('lastsessioninvalidation');
|
|
if ($lastinvalidation === false) {
|
|
// This is a new session, there won't be anything to invalidate. Set the time of the last invalidation and
|
|
// move on.
|
|
$this->set('lastsessioninvalidation', cache::now());
|
|
return;
|
|
} else if ($lastinvalidation == cache::now()) {
|
|
// We've already invalidated during this request.
|
|
return;
|
|
}
|
|
|
|
// Get the event invalidation cache.
|
|
$cache = cache::make('core', 'eventinvalidation');
|
|
$events = $cache->get_many($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 => $timestamp) {
|
|
// If the timestamp of the event is more than or equal to the last invalidation (happened between the last
|
|
// invalidation and now)then we need to invaliate the key.
|
|
if ($timestamp >= $lastinvalidation) {
|
|
if ($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.
|
|
$this->set('lastsessioninvalidation', cache::now());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
if ($key === 'lastaccess') {
|
|
$key = '__lastaccess__';
|
|
}
|
|
return 'sess_'.parent::parse_key($key);
|
|
}
|
|
|
|
/**
|
|
* Check that this cache instance is tracking the current user.
|
|
*/
|
|
protected function check_tracked_user() {
|
|
if (isset($_SESSION['USER']->id)) {
|
|
// 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();
|
|
// Update the session id just in case!
|
|
$this->sessionid = session_id();
|
|
}
|
|
self::$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();
|
|
$this->currentuserid = $new;
|
|
// Update the session id just in case!
|
|
$this->sessionid = session_id();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Gets the session data.
|
|
*
|
|
* @param bool $force If true the session data will be loaded from the store again.
|
|
* @return array An array of session data.
|
|
*/
|
|
protected function get_session_data($force = false) {
|
|
if ($this->sessionid === null) {
|
|
$this->sessionid = session_id();
|
|
}
|
|
if (is_array($this->session) && !$force) {
|
|
return $this->session;
|
|
}
|
|
$session = parent::get($this->sessionid);
|
|
if ($session === false) {
|
|
$session = array();
|
|
}
|
|
// We have to write here to ensure that the lastaccess time is recorded.
|
|
// And also in order to ensure the session entry exists as when we save it on __destruct
|
|
// $CFG is likely to have already been destroyed.
|
|
$this->save_session($session);
|
|
return $this->session;
|
|
}
|
|
|
|
/**
|
|
* Saves the session data.
|
|
*
|
|
* This function also updates the last access time.
|
|
*
|
|
* @param array $session
|
|
* @return bool
|
|
*/
|
|
protected function save_session(array $session) {
|
|
$session['lastaccess'] = time();
|
|
$this->session = $session;
|
|
return parent::set($this->sessionid, $this->session);
|
|
}
|
|
|
|
/**
|
|
* 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 $strictness One of IGNORE_MISSING | MUST_EXIST
|
|
* @return mixed|false The data from the cache or false if the key did not exist within the cache.
|
|
* @throws moodle_exception
|
|
*/
|
|
public function get($key, $strictness = IGNORE_MISSING) {
|
|
// Check the tracked user.
|
|
$this->check_tracked_user();
|
|
// 2. Parse the key.
|
|
$parsedkey = $this->parse_key($key);
|
|
// 3. Get it from the store.
|
|
$result = false;
|
|
$session = $this->get_session_data();
|
|
if (array_key_exists($parsedkey, $session)) {
|
|
$result = $session[$parsedkey];
|
|
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.
|
|
$setaftervalidation = false;
|
|
if ($result === false) {
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_miss('**static session**', $this->get_definition()->get_id());
|
|
}
|
|
if ($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);
|
|
}
|
|
$setaftervalidation = ($result !== false);
|
|
} else if ($this->perfdebug) {
|
|
cache_helper::record_cache_hit('**static session**', $this->get_definition()->get_id());
|
|
}
|
|
// 5. Validate strictness.
|
|
if ($strictness === MUST_EXIST && $result === false) {
|
|
throw new moodle_exception('Requested key did not exist in any cache stores and could not be loaded.');
|
|
}
|
|
// 6. Set it to the store if we got it from the loader/datasource.
|
|
if ($setaftervalidation) {
|
|
$this->set($key, $result);
|
|
}
|
|
// 7. Make sure we don't pass back anything that could be a reference.
|
|
// We don't want people modifying the data in the cache.
|
|
if (!is_scalar($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;
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
$this->check_tracked_user();
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_set('**static session**', $this->get_definition()->get_id());
|
|
}
|
|
if (is_object($data) && $data instanceof cacheable_object) {
|
|
$data = new cache_cached_object($data);
|
|
} else if (!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()) {
|
|
$data = new cache_ttl_wrapper($data, $this->get_definition()->get_ttl());
|
|
}
|
|
$session = $this->get_session_data();
|
|
$session[$this->parse_key($key)] = $data;
|
|
return $this->save_session($session);
|
|
}
|
|
|
|
/**
|
|
* 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->check_tracked_user();
|
|
$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);
|
|
}
|
|
$session = $this->get_session_data();
|
|
unset($session[$parsedkey]);
|
|
return $this->save_session($session);
|
|
}
|
|
|
|
/**
|
|
* 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 moodle_exception
|
|
*/
|
|
public function get_many(array $keys, $strictness = IGNORE_MISSING) {
|
|
$this->check_tracked_user();
|
|
$return = array();
|
|
foreach ($keys as $key) {
|
|
$return[$key] = $this->get($key, $strictness);
|
|
}
|
|
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) {
|
|
$this->check_tracked_user();
|
|
$parsedkeys = array_map(array($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);
|
|
}
|
|
$session = $this->get_session_data();
|
|
foreach ($parsedkeys as $parsedkey) {
|
|
unset($session[$parsedkey]);
|
|
}
|
|
$this->save_session($session);
|
|
return count($keys);
|
|
}
|
|
|
|
/**
|
|
* 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();
|
|
$session = $this->get_session_data();
|
|
$simulatettl = $this->has_a_ttl();
|
|
foreach ($keyvaluearray as $key => $value) {
|
|
if (is_object($value) && $value instanceof cacheable_object) {
|
|
$value = new cache_cached_object($value);
|
|
} else 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);
|
|
}
|
|
if ($simulatettl) {
|
|
$value = new cache_ttl_wrapper($value, $this->get_definition()->get_ttl());
|
|
}
|
|
$parsedkey = $this->parse_key($key);
|
|
$session[$parsedkey] = $value;
|
|
}
|
|
if ($this->perfdebug) {
|
|
cache_helper::record_cache_set($this->storetype, $this->get_definition()->get_id());
|
|
}
|
|
$this->save_session($session);
|
|
return count($keyvaluearray);
|
|
}
|
|
|
|
/**
|
|
* Purges the cache store, and loader if there is one.
|
|
*
|
|
* @return bool True on success, false otherwise
|
|
*/
|
|
public function purge() {
|
|
// 1. Purge the session object.
|
|
$this->session = array();
|
|
// 2. Delete the record for this users session from the store.
|
|
$this->get_store()->delete($this->sessionid);
|
|
// 3. Optionally purge any stacked loaders in the same way.
|
|
if ($this->get_loader()) {
|
|
$this->get_loader()->delete($this->sessionid);
|
|
}
|
|
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);
|
|
$session = $this->get_session_data();
|
|
$has = false;
|
|
if ($this->has_a_ttl()) {
|
|
// The data has a TTL and the store doesn't support it natively.
|
|
// We must fetch the data and expect a ttl wrapper.
|
|
if (array_key_exists($parsedkey, $session)) {
|
|
$data = $session[$parsedkey];
|
|
$has = ($data instanceof cache_ttl_wrapper && !$data->has_expired());
|
|
}
|
|
} else {
|
|
$has = array_key_exists($parsedkey, $session);
|
|
}
|
|
if (!$has && $tryloadifpossible) {
|
|
if ($this->get_loader() !== false) {
|
|
$result = $this->get_loader()->get($key);
|
|
} 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();
|
|
$session = $this->get_session_data();
|
|
foreach ($keys as $key) {
|
|
$has = false;
|
|
$parsedkey = $this->parse_key($key);
|
|
if ($this->has_a_ttl()) {
|
|
// The data has a TTL and the store doesn't support it natively.
|
|
// We must fetch the data and expect a ttl wrapper.
|
|
if (array_key_exists($parsedkey, $session)) {
|
|
$data = $session[$parsedkey];
|
|
$has = ($data instanceof cache_ttl_wrapper && !$data->has_expired());
|
|
}
|
|
} else {
|
|
$has = array_key_exists($parsedkey, $session);
|
|
}
|
|
if (!$has) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
$this->check_tracked_user();
|
|
$session = $this->get_session_data();
|
|
foreach ($keys as $key) {
|
|
$has = false;
|
|
$parsedkey = $this->parse_key($key);
|
|
if ($this->has_a_ttl()) {
|
|
// The data has a TTL and the store doesn't support it natively.
|
|
// We must fetch the data and expect a ttl wrapper.
|
|
if (array_key_exists($parsedkey, $session)) {
|
|
$data = $session[$parsedkey];
|
|
$has = ($data instanceof cache_ttl_wrapper && !$data->has_expired());
|
|
}
|
|
} else {
|
|
$has = array_key_exists($parsedkey, $session);
|
|
}
|
|
if ($has) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* The session loader never uses the persist cache.
|
|
* Instead it stores things in the static $session variable. Shared between all session loaders.
|
|
*
|
|
* @return bool
|
|
*/
|
|
protected function is_using_persist_cache() {
|
|
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 ;) !
|
|
} |