111 lines
3 KiB
PHP
111 lines
3 KiB
PHP
<?php
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/**
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* @author Robin Appelman <icewind@owncloud.com>
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*
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* @copyright Copyright (c) 2015, ownCloud, Inc.
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* @license AGPL-3.0
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*
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* This code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License, version 3,
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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*/
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namespace OC\Lock;
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use OCP\Lock\LockedException;
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use OCP\IMemcache;
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class MemcacheLockingProvider extends AbstractLockingProvider {
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/**
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* @var \OCP\IMemcache
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*/
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private $memcache;
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/**
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* @param \OCP\IMemcache $memcache
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*/
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public function __construct(IMemcache $memcache) {
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$this->memcache = $memcache;
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}
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/**
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* @param string $path
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* @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
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* @return bool
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*/
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public function isLocked($path, $type) {
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$lockValue = $this->memcache->get($path);
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if ($type === self::LOCK_SHARED) {
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return $lockValue > 0;
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} else if ($type === self::LOCK_EXCLUSIVE) {
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return $lockValue === 'exclusive';
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} else {
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return false;
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}
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}
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/**
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* @param string $path
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* @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
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* @throws \OCP\Lock\LockedException
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*/
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public function acquireLock($path, $type) {
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if ($type === self::LOCK_SHARED) {
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if (!$this->memcache->inc($path)) {
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throw new LockedException($path);
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}
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} else {
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$this->memcache->add($path, 0);
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if (!$this->memcache->cas($path, 0, 'exclusive')) {
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throw new LockedException($path);
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}
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}
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$this->markAcquire($path, $type);
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}
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/**
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* @param string $path
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* @param int $type self::LOCK_SHARED or self::LOCK_EXCLUSIVE
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*/
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public function releaseLock($path, $type) {
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if ($type === self::LOCK_SHARED) {
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if (isset($this->acquiredLocks['shared'][$path]) and $this->acquiredLocks['shared'][$path] > 0) {
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$this->memcache->dec($path);
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$this->memcache->cad($path, 0);
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}
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} else if ($type === self::LOCK_EXCLUSIVE) {
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$this->memcache->cad($path, 'exclusive');
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}
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$this->markRelease($path, $type);
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}
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/**
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* Change the type of an existing lock
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*
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* @param string $path
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* @param int $targetType self::LOCK_SHARED or self::LOCK_EXCLUSIVE
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* @throws \OCP\Lock\LockedException
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*/
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public function changeLock($path, $targetType) {
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if ($targetType === self::LOCK_SHARED) {
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if (!$this->memcache->cas($path, 'exclusive', 1)) {
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throw new LockedException($path);
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}
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} else if ($targetType === self::LOCK_EXCLUSIVE) {
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// we can only change a shared lock to an exclusive if there's only a single owner of the shared lock
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if (!$this->memcache->cas($path, 1, 'exclusive')) {
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throw new LockedException($path);
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}
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}
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$this->markChange($path, $targetType);
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}
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}
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