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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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/**
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* Defines abstract factory class for generating locks.
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*
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* @package core
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* @copyright Damyon Wiese 2013
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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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namespace core\lock;
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defined('MOODLE_INTERNAL') || die();
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/**
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* Defines abstract factory class for generating locks.
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*
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* @package core
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* @category lock
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* @copyright Damyon Wiese 2013
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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 lock_factory {
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/**
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* Define the constructor signature required by the lock_config class.
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*
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* @param string $type - The type this lock is used for (e.g. cron, cache)
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*/
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public function __construct($type);
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/**
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* Return information about the blocking behaviour of the locks on this platform.
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*
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* @return boolean - False if attempting to get a lock will block indefinitely.
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*/
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public function supports_timeout();
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/**
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* Will this lock be automatically released when the process ends.
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* This should never be relied upon in code - but is useful in the case of
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* fatal errors. If a lock type does not support this auto release,
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* the max lock time parameter must be obeyed to eventually clean up a lock.
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*
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* @return boolean - True if this lock type will be automatically released when the current process ends.
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*/
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public function supports_auto_release();
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/**
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* Is available.
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*
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* @return boolean - True if this lock type is available in this environment.
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*/
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public function is_available();
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/**
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* Get a lock within the specified timeout or return false.
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*
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* @param string $resource - The identifier for the lock. Should use frankenstyle prefix.
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* @param int $timeout - The number of seconds to wait for a lock before giving up.
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* Not all lock types will support this.
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* @param int $maxlifetime - The number of seconds to wait before reclaiming a stale lock.
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* Not all lock types will use this - e.g. if they support auto releasing
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* a lock when a process ends.
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* @return \core\lock\lock|boolean - An instance of \core\lock\lock if the lock was obtained, or false.
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*/
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public function get_lock($resource, $timeout, $maxlifetime = 86400);
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/**
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* Release a lock that was previously obtained with @lock.
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*
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* @param lock $lock - The lock to release.
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* @return boolean - True if the lock is no longer held (including if it was never held).
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*/
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public function release_lock(lock $lock);
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}
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