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efrain |
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<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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namespace core_cache;
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/**
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* Create and keep an instance of this class to allow temporary caches when caches are disabled.
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*
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* This class works together with code in {@see cache_factory_disabled}.
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*
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* The intention is that temporary cache should be short-lived (not for the entire install process),
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* which avoids two problems: first, that we might run out of memory for the caches, and second,
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* that some code e.g. install.php/upgrade.php files, is entitled to assume that caching is not
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* used and make direct database changes.
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*
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* @package core_cache
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* @copyright 2022 The Open University
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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 allow_temporary_caches {
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/** @var int Number of references of this class; if more than 0, temporary caches are allowed */
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protected static $references = 0;
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/**
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* Constructs an instance of this class.
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*
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* Temporary caches will be allowed until this instance goes out of scope. Store this token
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* in a local variable, so that the caches have a limited life; do not save it outside your
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* function.
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*
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* If cache is not disabled then normal (non-temporary) caches will be used, and this class
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* does nothing.
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*
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* If an object of this class already exists then creating (or destroying) another one will
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* have no effect.
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*/
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public function __construct() {
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self::$references++;
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}
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/**
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* Destroys an instance of this class.
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*
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* You do not need to call this manually; PHP will call it automatically when your variable
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* goes out of scope. If you do need to remove your token at other times, use unset($token);
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*
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* If there are no other instances of this object, then all temporary caches will be discarded.
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*/
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public function __destruct() {
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global $CFG;
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require_once($CFG->dirroot . '/cache/disabledlib.php');
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self::$references--;
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if (self::$references === 0) {
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\cache_factory_disabled::clear_temporary_caches();
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}
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}
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/**
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* Checks if temp caches are currently allowed.
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*
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* @return bool True if allowed
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*/
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public static function is_allowed(): bool {
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return self::$references > 0;
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}
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}
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