coding standards

[friendica.git] / src / Core / Lock / CacheLockDriver.php

diff --git a/src/Core/Lock/CacheLockDriver.php b/src/Core/Lock/CacheLockDriver.php
index 1bb768bd0f180b4abc09d52ad73afcf34cb1ea8f..18d441ffea09d5a0910ec6ac3ada461db885ab7c 100644 (file)
--- a/src/Core/Lock/CacheLockDriver.php
+++ b/src/Core/Lock/CacheLockDriver.php
@@ -2,7 +2,8 @@
 
 namespace Friendica\Core\Lock;
 
-use Friendica\Core\Cache\ICacheDriver;
+use Friendica\Core\Cache;
+use Friendica\Core\Cache\IMemoryCacheDriver;
 
 class CacheLockDriver extends AbstractLockDriver
 {
@@ -14,76 +15,75 @@ class CacheLockDriver extends AbstractLockDriver
        /**
         * CacheLockDriver constructor.
         *
-        * @param ICacheDriver $cache The CacheDriver for this type of lock
+        * @param IMemoryCacheDriver $cache The CacheDriver for this type of lock
         */
-       public function __construct(ICacheDriver $cache)
+       public function __construct(IMemoryCacheDriver $cache)
        {
                $this->cache = $cache;
        }
 
        /**
-        *
-        * @brief Sets a lock for a given name
-        *
-        * @param string $key The Name of the lock
-        * @param integer $timeout Seconds until we give up
-        *
-        * @return boolean Was the lock successful?
+        * (@inheritdoc)
         */
-       public function acquireLock($key, $timeout = 120)
+       public function acquireLock($key, $timeout = 120, $ttl = Cache::FIVE_MINUTES)
        {
                $got_lock = false;
                $start = time();
 
-               $cachekey = get_app()->get_hostname() . ";lock:" . $key;
+               $cachekey = self::getLockKey($key);
 
                do {
                        $lock = $this->cache->get($cachekey);
+                       // When we do want to lock something that was already locked by us.
+                       if ((int)$lock == getmypid()) {
+                               $got_lock = true;
+                       }
 
-                       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())) {
-                                       $lock = false;
+                       // When we do want to lock something new
+                       if (is_null($lock)) {
+                               // At first initialize it with "0"
+                               $this->cache->add($cachekey, 0);
+                               // Now the value has to be "0" because otherwise the key was used by another process meanwhile
+                               if ($this->cache->compareSet($cachekey, 0, getmypid(), $ttl)) {
+                                       $got_lock = true;
+                                       $this->markAcquire($key);
                                }
                        }
-                       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 $key Name of the lock
-        *
-        * @return mixed
+        * (@inheritdoc)
         */
        public function releaseLock($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);
-                       }
-               }
+               $cachekey = self::getLockKey($key);
 
+               $this->cache->compareDelete($cachekey, getmypid());
                $this->markRelease($key);
+       }
+
+       /**
+        * (@inheritdoc)
+        */
+       public function isLocked($key)
+       {
+               $cachekey = self::getLockKey($key);
+               $lock = $this->cache->get($cachekey);
+               return isset($lock) && ($lock !== false);
+       }
 
-               return;
+       /**
+        * @param string $key   The original key
+        * @return string               The cache key used for the cache
+        */
+       private static function getLockKey($key) {
+               return "lock:" . $key;
        }
 }