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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 store feature: locking.
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*
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* This is a feature that cache stores can implement if they wish to support locking themselves rather
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* than having the cache loader handle it for them.
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*
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* Can be implemented by classes already implementing store.
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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 lockable_cache_interface {
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/**
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* Acquires a lock on the given key for the given identifier.
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*
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* @param string $key The key we are locking.
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* @param string $ownerid The identifier so we can check if we have the lock or if it is someone else.
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* The use of this property is entirely optional and implementations can act as they like upon it.
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* @return bool True if the lock could be acquired, false otherwise.
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*/
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public function acquire_lock($key, $ownerid);
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/**
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* Test if there is already a lock for the given key and if there is whether it belongs to the calling code.
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*
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* @param string $key The key we are locking.
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* @param string $ownerid The identifier so we can check if we have the lock or if it is someone else.
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* @return bool True if this code has the lock, false if there is a lock but this code doesn't have it, null if there
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* is no lock.
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*/
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public function check_lock_state($key, $ownerid);
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/**
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* Releases the lock on the given key.
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*
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* @param string $key The key we are locking.
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* @param string $ownerid The identifier so we can check if we have the lock or if it is someone else.
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* The use of this property is entirely optional and implementations can act as they like upon it.
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* @return bool True if the lock has been released, false if there was a problem releasing the lock.
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*/
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public function release_lock($key, $ownerid);
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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(lockable_cache_interface::class, \cache_is_lockable::class);
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