130 lines
3.7 KiB
PHP
130 lines
3.7 KiB
PHP
<?php
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/**
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* Data caching with dependencies.
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*
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* This program 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 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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 along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Cache
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*/
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/**
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* This class stores an arbitrary value along with its dependencies.
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* Users should typically only use DependencyWrapper::getValueFromCache(),
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* rather than instantiating one of these objects directly.
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* @ingroup Cache
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*/
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class DependencyWrapper {
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private $value;
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/** @var CacheDependency[] */
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private $deps;
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/**
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* @param mixed $value The user-supplied value
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* @param CacheDependency|CacheDependency[] $deps A dependency or dependency
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* array. All dependencies must be objects implementing CacheDependency.
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*/
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public function __construct( $value = false, $deps = [] ) {
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$this->value = $value;
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if ( !is_array( $deps ) ) {
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$deps = [ $deps ];
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}
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$this->deps = $deps;
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}
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/**
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* Returns true if any of the dependencies have expired
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*
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* @return bool
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*/
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public function isExpired() {
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foreach ( $this->deps as $dep ) {
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if ( $dep->isExpired() ) {
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return true;
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}
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}
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return false;
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}
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/**
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* Initialise dependency values in preparation for storing. This must be
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* called before serialization.
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*/
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public function initialiseDeps() {
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foreach ( $this->deps as $dep ) {
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$dep->loadDependencyValues();
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}
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}
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/**
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* Get the user-defined value
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* @return bool|mixed
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*/
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public function getValue() {
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return $this->value;
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}
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/**
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* Store the wrapper to a cache
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*
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* @param BagOStuff $cache
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* @param string $key
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* @param int $expiry
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*/
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public function storeToCache( $cache, $key, $expiry = 0 ) {
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$this->initialiseDeps();
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$cache->set( $key, $this, $expiry );
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}
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/**
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* Attempt to get a value from the cache. If the value is expired or missing,
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* it will be generated with the callback function (if present), and the newly
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* calculated value will be stored to the cache in a wrapper.
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*
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* @param BagOStuff $cache
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* @param string $key The cache key
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* @param int $expiry The expiry timestamp or interval in seconds
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* @param bool|callable $callback The callback for generating the value, or false
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* @param array $callbackParams The function parameters for the callback
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* @param array $deps The dependencies to store on a cache miss. Note: these
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* are not the dependencies used on a cache hit! Cache hits use the stored
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* dependency array.
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*
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* @return mixed The value, or null if it was not present in the cache and no
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* callback was defined.
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*/
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public static function getValueFromCache( $cache, $key, $expiry = 0, $callback = false,
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$callbackParams = [], $deps = []
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) {
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$obj = $cache->get( $key );
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if ( is_object( $obj ) && $obj instanceof DependencyWrapper && !$obj->isExpired() ) {
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$value = $obj->value;
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} elseif ( $callback ) {
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$value = $callback( ...$callbackParams );
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# Cache the newly-generated value
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$wrapper = new DependencyWrapper( $value, $deps );
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$wrapper->storeToCache( $cache, $key, $expiry );
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} else {
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$value = null;
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}
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return $value;
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}
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}
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