redesign of locking & caching

- New Factory "CacheDriverFactory" for Cache and Locks
- Adding Redis/Memcached Locking
- Moved Lock to Core
- other improvements

src/Core/Lock/AbstractLockDriver.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+/**
+ * Class AbstractLockDriver
+ *
+ * @package Friendica\Core\Lock
+ *
+ * @brief Basic class for Locking with common functions (local acquired locks, releaseAll, ..)
+ */
+abstract class AbstractLockDriver implements ILockDriver
+{
+	/**
+	 * @var array The local acquired locks
+	 */
+	protected $acquiredLocks = [];
+
+	/**
+	 * @brief Check if we've locally acquired a lock
+	 *
+	 * @param string key The Name of the lock
+	 * @return bool      Returns true if the lock is set
+	 */
+	protected function hasAcquiredLock(string $key): bool {
+		return isset($this->acquireLock[$key]);
+	}
+
+	/**
+	 * @brief Mark a locally acquired lock
+	 *
+	 * @param string $key The Name of the lock
+	 */
+	protected function markAcquire(string $key) {
+		$this->acquiredLocks[$key] = true;
+	}
+
+	/**
+	 * @brief Mark a release of a locally acquired lock
+	 *
+	 * @param string $key The Name of the lock
+	 */
+	protected function markRelease(string $key) {
+		unset($this->acquiredLocks[$key]);
+	}
+
+	/**
+	 * @brief Releases all lock that were set by us
+	 *
+	 * @return void
+	 */
+	public function releaseAll() {
+		foreach ($this->acquiredLocks as $acquiredLock) {
+			$this->releaseLock($acquiredLock);
+		}
+	}
+}

src/Core/Lock/CacheLockDriver.php

@@ -0,0 +1,89 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+use Friendica\Core\Cache\ICacheDriver;
+
+class CacheLockDriver extends AbstractLockDriver
+{
+	/**
+	 * @var \Friendica\Core\Cache\ICacheDriver;
+	 */
+	private $cache;
+
+	/**
+	 * CacheLockDriver constructor.
+	 *
+	 * @param ICacheDriver $cache The CacheDriver for this type of lock
+	 */
+	public function __construct(ICacheDriver $cache)
+	{
+		$this->cache = $cache;
+	}
+
+	/**
+	 *
+	 * @brief Sets a lock for a given name
+	 *
+	 * @param string $key The Name of the lock
+	 * @param integer $timeout Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public function acquireLock(string $key, int $timeout = 120)
+	{
+		$got_lock = false;
+		$start = time();
+
+		$cachekey = get_app()->get_hostname() . ";lock:" . $key;
+
+		do {
+			$lock = $this->cache->get($cachekey);
+
+			if (!is_bool($lock)) {
+				$pid = (int)$lock;
+
+				// When the process id isn't used anymore, we can safely claim the lock for us.
+				// Or we do want to lock something that was already locked by us.
+				if (!posix_kill($pid, 0) || ($pid == getmypid())) {
+					$lock = false;
+				}
+			}
+			if (is_bool($lock)) {
+				$this->cache->set($cachekey, getmypid(), 300);
+				$got_lock = true;
+			}
+
+			if (!$got_lock && ($timeout > 0)) {
+				usleep(rand(10000, 200000));
+			}
+		} while (!$got_lock && ((time() - $start) < $timeout));
+
+		$this->markAcquire($key);
+
+		return $got_lock;
+	}
+
+	/**
+	 * @brief Removes a lock if it was set by us
+	 *
+	 * @param string $key Name of the lock
+	 *
+	 * @return mixed
+	 */
+	public function releaseLock(string $key)
+	{
+		$cachekey = get_app()->get_hostname() . ";lock:" . $key;
+		$lock = $this->cache->get($cachekey);
+
+		if (!is_bool($lock)) {
+			if ((int)$lock == getmypid()) {
+				$this->cache->delete($cachekey);
+			}
+		}
+
+		$this->markRelease($key);
+
+		return;
+	}
+}

src/Core/Lock/DatabaseLockDriver.php

@@ -0,0 +1,89 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+use dba;
+use Friendica\Database\DBM;
+
+/**
+ * Locking driver that stores the locks in the database
+ */
+class DatabaseLockDriver extends AbstractLockDriver
+{
+	/**
+	 * @brief Sets a lock for a given name
+	 *
+	 * @param string  $key      The Name of the lock
+	 * @param integer $timeout  Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public function acquireLock(string $key, int $timeout = 120)
+	{
+		$got_lock = false;
+		$start = time();
+
+		do {
+			dba::lock('locks');
+			$lock = dba::selectFirst('locks', ['locked', 'pid'], ['name' => $key]);
+
+			if (DBM::is_result($lock)) {
+				if ($lock['locked']) {
+					// When the process id isn't used anymore, we can safely claim the lock for us.
+					if (!posix_kill($lock['pid'], 0)) {
+						$lock['locked'] = false;
+					}
+					// We want to lock something that was already locked by us? So we got the lock.
+					if ($lock['pid'] == getmypid()) {
+						$got_lock = true;
+					}
+				}
+				if (!$lock['locked']) {
+					dba::update('locks', ['locked' => true, 'pid' => getmypid()], ['name' => $key]);
+					$got_lock = true;
+				}
+			} else {
+				dba::insert('locks', ['name' => $key, 'locked' => true, 'pid' => getmypid()]);
+				$got_lock = true;
+			}
+
+			dba::unlock();
+
+			if (!$got_lock && ($timeout > 0)) {
+				usleep(rand(100000, 2000000));
+			}
+		} while (!$got_lock && ((time() - $start) < $timeout));
+
+		$this->markAcquire($key);
+
+		return $got_lock;
+	}
+
+	/**
+	 * @brief Removes a lock if it was set by us
+	 *
+	 * @param string $key Name of the lock
+	 *
+	 * @return mixed
+	 */
+	public function releaseLock(string $key)
+	{
+		dba::delete('locks', ['locked' => false, 'pid' => 0], ['name' => $key, 'pid' => getmypid()]);
+
+		$this->releaseLock($key);
+
+		return;
+	}
+
+	/**
+	 * @brief Removes all lock that were set by us
+	 *
+	 * @return void
+	 */
+	public function releaseAll()
+	{
+		dba::delete('locks', ['locked' => false, 'pid' => 0], ['pid' => getmypid()]);
+
+		$this->acquiredLocks = [];
+	}
+}

src/Core/Lock/ILockDriver.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+/**
+ * Lock Driver Interface
+ *
+ * @author Philipp Holzer <admin@philipp.info>
+ */
+interface ILockDriver
+{
+	/**
+	 *
+	 * @brief Acquires a lock for a given name
+	 *
+	 * @param string  $key      The Name of the lock
+	 * @param integer $timeout  Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public function acquireLock(string $key, int $timeout = 120);
+
+	/**
+	 * @brief Releases a lock if it was set by us
+	 *
+	 * @param string $key The Name of the lock
+	 *
+	 * @return void
+	 */
+	public function releaseLock(string $key);
+
+	/**
+	 * @brief Releases all lock that were set by us
+	 *
+	 * @return void
+	 */
+	public function releaseAll();
+}

src/Core/Lock/SemaphoreLockDriver.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace Friendica\Core\Lock;
+
+class SemaphoreLockDriver extends AbstractLockDriver
+{
+	public function __construct()
+	{
+		if (!function_exists('sem_get')) {
+			throw new \Exception('Semaphore lock not supported');
+		}
+	}
+
+	/**
+	 * @brief Creates a semaphore key
+	 *
+	 * @param string $key Name of the lock
+	 *
+	 * @return integer the semaphore key
+	 */
+	private static function semaphoreKey(string $key): int
+	{
+		$temp = get_temppath();
+
+		$file = $temp.'/'.$key.'.sem';
+
+		if (!file_exists($file)) {
+			file_put_contents($file, $key);
+		}
+
+		return ftok($file, 'f');
+	}
+
+	/**
+	 *
+	 * @brief Sets a lock for a given name
+	 *
+	 * @param string $key The Name of the lock
+	 * @param integer $timeout Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public function acquireLock(string $key, int $timeout = 120)
+	{
+		$this->acquiredLocks[$key] = sem_get(self::semaphoreKey($key));
+		if ($this->acquiredLocks[$key]) {
+			return sem_acquire($this->acquiredLocks[$key], ($timeout == 0));
+		}
+	}
+
+	/**
+	 * @brief Removes a lock if it was set by us
+	 *
+	 * @param string $key Name of the lock
+	 *
+	 * @return mixed
+	 */
+	public function releaseLock(string $key)
+	{
+		if (empty($this->acquiredLocks[$key])) {
+			return false;
+		} else {
+			$success = @sem_release($this->acquiredLocks[$key]);
+			unset($this->acquiredLocks[$key]);
+			return $success;
+		}
+	}
+}