mirror of
https://github.com/friendica/friendica
synced 2024-09-26 04:51:22 +02:00
181 lines
4.5 KiB
PHP
181 lines
4.5 KiB
PHP
<?php
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/**
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* @copyright Copyright (C) 2010-2022, the Friendica project
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*
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* @license GNU AGPL version 3 or any later version
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*
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* This program 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 as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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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
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*
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*/
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namespace Friendica\Core\Lock\Type;
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use Friendica\Core\Cache\Capability\ICanCache;
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use Friendica\Core\Cache\Capability\ICanCacheInMemory;
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use Friendica\Core\Cache\Enum\Duration;
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use Friendica\Core\Cache\Exception\CachePersistenceException;
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use Friendica\Core\Lock\Exception\LockPersistenceException;
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class CacheLock extends AbstractLock
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{
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/**
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* @var string The static prefix of all locks inside the cache
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*/
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const CACHE_PREFIX = 'lock:';
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/**
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* @var ICanCache;
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*/
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private $cache;
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/**
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* CacheLock constructor.
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*
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* @param ICanCacheInMemory $cache The CacheDriver for this type of lock
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*/
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public function __construct(ICanCacheInMemory $cache)
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{
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$this->cache = $cache;
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}
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/**
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* (@inheritdoc)
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*/
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public function acquire(string $key, int $timeout = 120, int $ttl = Duration::FIVE_MINUTES): bool
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{
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$got_lock = false;
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$start = time();
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$lockKey = self::getLockKey($key);
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try {
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do {
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$lock = $this->cache->get($lockKey);
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// When we do want to lock something that was already locked by us.
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if ((int)$lock == getmypid()) {
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$got_lock = true;
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}
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// When we do want to lock something new
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if (is_null($lock)) {
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// At first initialize it with "0"
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$this->cache->add($lockKey, 0);
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// Now the value has to be "0" because otherwise the key was used by another process meanwhile
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if ($this->cache->compareSet($lockKey, 0, getmypid(), $ttl)) {
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$got_lock = true;
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$this->markAcquire($key);
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}
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}
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if (!$got_lock && ($timeout > 0)) {
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usleep(rand(10000, 200000));
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}
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} while (!$got_lock && ((time() - $start) < $timeout));
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} catch (CachePersistenceException $exception) {
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throw new LockPersistenceException(sprintf('Cannot acquire lock for key %s', $key), $exception);
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}
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return $got_lock;
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}
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/**
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* (@inheritdoc)
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*/
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public function release(string $key, bool $override = false): bool
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{
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$lockKey = self::getLockKey($key);
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try {
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if ($override) {
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$return = $this->cache->delete($lockKey);
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} else {
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$return = $this->cache->compareDelete($lockKey, getmypid());
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}
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} catch (CachePersistenceException $exception) {
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throw new LockPersistenceException(sprintf('Cannot release lock for key %s (override %b)', $key, $override), $exception);
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}
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$this->markRelease($key);
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return $return;
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}
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/**
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* (@inheritdoc)
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*/
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public function isLocked(string $key): bool
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{
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$lockKey = self::getLockKey($key);
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try {
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$lock = $this->cache->get($lockKey);
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} catch (CachePersistenceException $exception) {
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throw new LockPersistenceException(sprintf('Cannot check lock state for key %s', $key), $exception);
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}
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return isset($lock) && ($lock !== false);
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}
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/**
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* {@inheritDoc}
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*/
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public function getName(): string
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{
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return $this->cache->getName();
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}
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/**
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* {@inheritDoc}
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*/
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public function getLocks(string $prefix = ''): array
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{
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try {
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$locks = $this->cache->getAllKeys(self::CACHE_PREFIX . $prefix);
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} catch (CachePersistenceException $exception) {
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throw new LockPersistenceException(sprintf('Cannot get locks with prefix %s', $prefix), $exception);
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}
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array_walk($locks, function (&$lock) {
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$lock = substr($lock, strlen(self::CACHE_PREFIX));
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});
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return $locks;
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}
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/**
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* {@inheritDoc}
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*/
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public function releaseAll(bool $override = false): bool
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{
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$success = parent::releaseAll($override);
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$locks = $this->getLocks();
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foreach ($locks as $lock) {
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if (!$this->release($lock, $override)) {
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$success = false;
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}
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}
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return $success;
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}
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/**
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* @param string $key The original key
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*
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* @return string The cache key used for the cache
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*/
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private static function getLockKey(string $key): string
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{
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return self::CACHE_PREFIX . $key;
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}
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}
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