136 lines
3.7 KiB
PHP
136 lines
3.7 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\IDBConnection;
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use OCP\Lock\LockedException;
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/**
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* Locking provider that stores the locks in the database
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*/
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class DBLockingProvider extends AbstractLockingProvider {
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/**
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* @var \OCP\IDBConnection
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*/
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private $connection;
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/**
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* @param \OCP\IDBConnection $connection
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*/
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public function __construct(IDBConnection $connection) {
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$this->connection = $connection;
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}
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protected function initLockField($path) {
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$this->connection->insertIfNotExist('*PREFIX*file_locks', ['key' => $path, 'lock' => 0, 'ttl' => 0], ['key']);
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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, $type) {
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$query = $this->connection->prepare('SELECT `lock` from `*PREFIX*file_locks` WHERE `key` = ?');
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$query->execute([$path]);
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$lockValue = (int)$query->fetchColumn();
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if ($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 === -1;
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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, $type) {
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$this->connection->beginTransaction();
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$this->initLockField($path);
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if ($type === self::LOCK_SHARED) {
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$result = $this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = `lock` + 1 WHERE `key` = ? AND `lock` >= 0',
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[$path]
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);
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} else {
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$result = $this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = -1 WHERE `key` = ? AND `lock` = 0',
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[$path]
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);
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}
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$this->connection->commit();
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if ($result !== 1) {
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throw new LockedException($path);
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}
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$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, $type) {
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$this->initLockField($path);
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if ($type === self::LOCK_SHARED) {
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$this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = `lock` - 1 WHERE `key` = ? AND `lock` > 0',
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[$path]
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);
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} else {
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$this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = 0 WHERE `key` = ? AND `lock` = -1',
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[$path]
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);
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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, $targetType) {
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$this->initLockField($path);
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if ($targetType === self::LOCK_SHARED) {
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$result = $this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = 1 WHERE `key` = ? AND `lock` = -1',
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[$path]
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);
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} else {
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$result = $this->connection->executeUpdate(
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'UPDATE `*PREFIX*file_locks` SET `lock` = -1 WHERE `key` = ? AND `lock` = 1',
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[$path]
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);
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}
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if ($result !== 1) {
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throw new LockedException($path);
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}
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$this->markChange($path, $targetType);
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}
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}
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