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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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* Cache lock interface.
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*
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* This interface needs to be inherited by all cache lock plugins.
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*
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* @package core_cache
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* @copyright 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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interface cache_lock_interface {
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/**
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* Constructs an instance of the cache lock given its name and its configuration data
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*
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* @param string $name The unique name of the lock instance
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* @param array $configuration
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*/
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public function __construct($name, array $configuration = []);
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/**
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* Acquires a lock on a given key.
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*
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* @param string $key The key to acquire a lock for.
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* @param string $ownerid An unique identifier for the owner of this lock. It is entirely optional for the cache lock plugin
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* to use this. Each implementation can decide for themselves.
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* @param bool $block If set to true the application will wait until a lock can be acquired
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* @return bool True if the lock can be acquired false otherwise.
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*/
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public function lock($key, $ownerid, $block = false);
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/**
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* Releases the lock held on a certain key.
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*
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* @param string $key The key to release the lock for.
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* @param string $ownerid An unique identifier for the owner of this lock. It is entirely optional for the cache lock plugin
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* to use this. Each implementation can decide for themselves.
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* @param bool $forceunlock If set to true the lock will be removed if it exists regardless of whether or not we own it.
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*/
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public function unlock($key, $ownerid, $forceunlock = false);
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/**
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* Checks the state of the given key.
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*
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* Returns true if the key is locked and belongs to the ownerid.
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* Returns false if the key is locked but does not belong to the ownerid.
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* Returns null if there is no lock
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*
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* @param string $key The key we are checking for.
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* @param string $ownerid The identifier so we can check if we have the lock or if it is someone else.
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* @return bool True if this code has the lock, false if there is a lock but this code doesn't have it, null if there
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* is no lock.
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*/
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public function check_state($key, $ownerid);
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/**
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* Cleans up any left over locks.
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*
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* This function MUST clean up any locks that have been acquired and not released during processing.
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* Although the situation of acquiring a lock and not releasing it should be insanely rare we need to deal with it.
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* Things such as unfortunate timeouts etc could cause this situation.
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*/
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public function __destruct();
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}
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// Alias this class to the old name.
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// This file will be autoloaded by the legacyclasses autoload system.
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// In future all uses of this class will be corrected and the legacy references will be removed.
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class_alias(cache_lock_interface::class, \cache_lock_interface::class);
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