src/Core/Lock/CacheLockDriver.php

   1 <?php
   2
   3 namespace Friendica\Core\Lock;
   4
   5 use Friendica\Core\Cache\ICacheDriver;
   6
   7 class CacheLockDriver extends AbstractLockDriver
   8 {
   9         /**
  10          * @var \Friendica\Core\Cache\ICacheDriver;
  11          */
  12         private $cache;
  13
  14         /**
  15          * CacheLockDriver constructor.
  16          *
  17          * @param ICacheDriver $cache The CacheDriver for this type of lock
  18          */
  19         public function __construct(ICacheDriver $cache)
  20         {
  21                 $this->cache = $cache;
  22         }
  23
  24         /**
  25          *
  26          * @brief Sets a lock for a given name
  27          *
  28          * @param string $key The Name of the lock
  29          * @param integer $timeout Seconds until we give up
  30          *
  31          * @return boolean Was the lock successful?
  32          */
  33         public function acquireLock($key, $timeout = 120)
  34         {
  35                 $got_lock = false;
  36                 $start = time();
  37
  38                 $cachekey = get_app()->get_hostname() . ";lock:" . $key;
  39
  40                 do {
  41                         $lock = $this->cache->get($cachekey);
  42
  43                         if (!is_bool($lock)) {
  44                                 $pid = (int)$lock;
  45
  46                                 // When the process id isn't used anymore, we can safely claim the lock for us.
  47                                 // Or we do want to lock something that was already locked by us.
  48                                 if (!posix_kill($pid, 0) || ($pid == getmypid())) {
  49                                         $lock = false;
  50                                 }
  51                         }
  52                         if (is_bool($lock)) {
  53                                 $this->cache->set($cachekey, getmypid(), 300);
  54                                 $got_lock = true;
  55                         }
  56
  57                         if (!$got_lock && ($timeout > 0)) {
  58                                 usleep(rand(10000, 200000));
  59                         }
  60                 } while (!$got_lock && ((time() - $start) < $timeout));
  61
  62                 $this->markAcquire($key);
  63
  64                 return $got_lock;
  65         }
  66
  67         /**
  68          * @brief Removes a lock if it was set by us
  69          *
  70          * @param string $key Name of the lock
  71          *
  72          * @return mixed
  73          */
  74         public function releaseLock($key)
  75         {
  76                 $cachekey = get_app()->get_hostname() . ";lock:" . $key;
  77                 $lock = $this->cache->get($cachekey);
  78
  79                 if (!is_bool($lock)) {
  80                         if ((int)$lock == getmypid()) {
  81                                 $this->cache->delete($cachekey);
  82                         }
  83                 }
  84
  85                 $this->markRelease($key);
  86
  87                 return;
  88         }
  89 }