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317 lines
8.8 KiB
317 lines
8.8 KiB
<?php |
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/** |
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* @copyright Copyright (c) 2016, ownCloud, Inc. |
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* |
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* @author Individual IT Services <info@individual-it.net> |
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* @author Lukas Reschke <lukas@statuscode.ch> |
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* @author Morris Jobke <hey@morrisjobke.de> |
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* @author Robin Appelman <robin@icewind.nl> |
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* @author Roeland Jago Douma <roeland@famdouma.nl> |
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* |
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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 Doctrine\DBAL\Exception\UniqueConstraintViolationException; |
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use OC\DB\QueryBuilder\Literal; |
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use OCP\AppFramework\Utility\ITimeFactory; |
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use OCP\DB\QueryBuilder\IQueryBuilder; |
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use OCP\IDBConnection; |
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use OCP\ILogger; |
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use OCP\Lock\ILockingProvider; |
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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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* @var \OCP\ILogger |
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*/ |
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private $logger; |
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/** |
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* @var \OCP\AppFramework\Utility\ITimeFactory |
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*/ |
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private $timeFactory; |
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private $sharedLocks = []; |
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/** |
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* @var bool |
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*/ |
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private $cacheSharedLocks; |
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/** |
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* Check if we have an open shared lock for a path |
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* |
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* @param string $path |
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* @return bool |
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*/ |
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protected function isLocallyLocked(string $path): bool { |
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return isset($this->sharedLocks[$path]) && $this->sharedLocks[$path]; |
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} |
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/** |
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* Mark a locally acquired lock |
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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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protected function markAcquire(string $path, int $type) { |
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parent::markAcquire($path, $type); |
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if ($this->cacheSharedLocks) { |
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if ($type === self::LOCK_SHARED) { |
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$this->sharedLocks[$path] = true; |
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} |
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} |
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} |
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/** |
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* Change the type of an existing tracked 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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*/ |
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protected function markChange(string $path, int $targetType) { |
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parent::markChange($path, $targetType); |
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if ($this->cacheSharedLocks) { |
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if ($targetType === self::LOCK_SHARED) { |
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$this->sharedLocks[$path] = true; |
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} else if ($targetType === self::LOCK_EXCLUSIVE) { |
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$this->sharedLocks[$path] = false; |
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} |
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} |
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} |
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/** |
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* @param \OCP\IDBConnection $connection |
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* @param \OCP\ILogger $logger |
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* @param \OCP\AppFramework\Utility\ITimeFactory $timeFactory |
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* @param int $ttl |
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* @param bool $cacheSharedLocks |
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*/ |
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public function __construct( |
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IDBConnection $connection, |
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ILogger $logger, |
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ITimeFactory $timeFactory, |
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int $ttl = 3600, |
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$cacheSharedLocks = true |
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) { |
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$this->connection = $connection; |
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$this->logger = $logger; |
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$this->timeFactory = $timeFactory; |
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$this->ttl = $ttl; |
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$this->cacheSharedLocks = $cacheSharedLocks; |
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} |
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/** |
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* Insert a file locking row if it does not exists. |
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* |
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* @param string $path |
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* @param int $lock |
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* @return int number of inserted rows |
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*/ |
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protected function initLockField(string $path, int $lock = 0): int { |
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$expire = $this->getExpireTime(); |
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return $this->connection->insertIgnoreConflict('file_locks', [ |
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'key' => $path, |
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'lock' => $lock, |
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'ttl' => $expire |
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]); |
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} |
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/** |
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* @return int |
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*/ |
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protected function getExpireTime(): int { |
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return $this->timeFactory->getTime() + $this->ttl; |
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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(string $path, int $type): bool { |
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if ($this->hasAcquiredLock($path, $type)) { |
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return true; |
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} |
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$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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if ($this->isLocallyLocked($path)) { |
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// if we have a shared lock we kept open locally but it's released we always have at least 1 shared lock in the db |
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return $lockValue > 1; |
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} else { |
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return $lockValue > 0; |
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} |
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} else if ($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(string $path, int $type) { |
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$expire = $this->getExpireTime(); |
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if ($type === self::LOCK_SHARED) { |
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if (!$this->isLocallyLocked($path)) { |
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$result = $this->initLockField($path, 1); |
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if ($result <= 0) { |
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$result = $this->connection->executeUpdate( |
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'UPDATE `*PREFIX*file_locks` SET `lock` = `lock` + 1, `ttl` = ? WHERE `key` = ? AND `lock` >= 0', |
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[$expire, $path] |
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); |
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} |
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} else { |
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$result = 1; |
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} |
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} else { |
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$existing = 0; |
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if ($this->hasAcquiredLock($path, ILockingProvider::LOCK_SHARED) === false && $this->isLocallyLocked($path)) { |
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$existing = 1; |
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} |
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$result = $this->initLockField($path, -1); |
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if ($result <= 0) { |
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$result = $this->connection->executeUpdate( |
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'UPDATE `*PREFIX*file_locks` SET `lock` = -1, `ttl` = ? WHERE `key` = ? AND `lock` = ?', |
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[$expire, $path, $existing] |
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); |
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} |
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} |
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if ($result !== 1) { |
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throw new LockedException($path); |
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} |
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$this->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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* @suppress SqlInjectionChecker |
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*/ |
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public function releaseLock(string $path, int $type) { |
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$this->markRelease($path, $type); |
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// we keep shared locks till the end of the request so we can re-use them |
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if ($type === self::LOCK_EXCLUSIVE) { |
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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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} else if (!$this->cacheSharedLocks) { |
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$query = $this->connection->getQueryBuilder(); |
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$query->update('file_locks') |
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->set('lock', $query->func()->subtract('lock', $query->createNamedParameter(1))) |
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->where($query->expr()->eq('key', $query->createNamedParameter($path))) |
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->andWhere($query->expr()->gt('lock', $query->createNamedParameter(0))); |
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$query->execute(); |
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} |
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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(string $path, int $targetType) { |
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$expire = $this->getExpireTime(); |
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if ($targetType === self::LOCK_SHARED) { |
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$result = $this->connection->executeUpdate( |
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'UPDATE `*PREFIX*file_locks` SET `lock` = 1, `ttl` = ? WHERE `key` = ? AND `lock` = -1', |
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[$expire, $path] |
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); |
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} else { |
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// since we only keep one shared lock in the db we need to check if we have more then one shared lock locally manually |
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if (isset($this->acquiredLocks['shared'][$path]) && $this->acquiredLocks['shared'][$path] > 1) { |
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throw new LockedException($path); |
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} |
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$result = $this->connection->executeUpdate( |
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'UPDATE `*PREFIX*file_locks` SET `lock` = -1, `ttl` = ? WHERE `key` = ? AND `lock` = 1', |
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[$expire, $path] |
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); |
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} |
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if ($result !== 1) { |
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throw new LockedException($path); |
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} |
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$this->markChange($path, $targetType); |
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} |
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/** |
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* cleanup empty locks |
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*/ |
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public function cleanExpiredLocks() { |
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$expire = $this->timeFactory->getTime(); |
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try { |
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$this->connection->executeUpdate( |
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'DELETE FROM `*PREFIX*file_locks` WHERE `ttl` < ?', |
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[$expire] |
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); |
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} catch (\Exception $e) { |
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// If the table is missing, the clean up was successful |
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if ($this->connection->tableExists('file_locks')) { |
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throw $e; |
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} |
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} |
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} |
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/** |
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* release all lock acquired by this instance which were marked using the mark* methods |
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* |
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* @suppress SqlInjectionChecker |
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*/ |
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public function releaseAll() { |
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parent::releaseAll(); |
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if (!$this->cacheSharedLocks) { |
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return; |
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} |
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// since we keep shared locks we need to manually clean those |
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$lockedPaths = array_keys($this->sharedLocks); |
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$lockedPaths = array_filter($lockedPaths, function ($path) { |
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return $this->sharedLocks[$path]; |
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}); |
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$chunkedPaths = array_chunk($lockedPaths, 100); |
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foreach ($chunkedPaths as $chunk) { |
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$builder = $this->connection->getQueryBuilder(); |
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$query = $builder->update('file_locks') |
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->set('lock', $builder->func()->subtract('lock', $builder->expr()->literal(1))) |
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->where($builder->expr()->in('key', $builder->createNamedParameter($chunk, IQueryBuilder::PARAM_STR_ARRAY))) |
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->andWhere($builder->expr()->gt('lock', new Literal(0))); |
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$query->execute(); |
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} |
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} |
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}
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