src/Core/Lock/SemaphoreLockDriver.php

   1 <?php
   2
   3 namespace Friendica\Core\Lock;
   4
   5 use Friendica\Core\Cache;
   6
   7 class SemaphoreLockDriver extends AbstractLockDriver
   8 {
   9         private static $semaphore = [];
  10
  11         public function __construct()
  12         {
  13                 if (!function_exists('sem_get')) {
  14                         throw new \Exception('Semaphore lock not supported');
  15                 }
  16         }
  17
  18         /**
  19          * (@inheritdoc)
  20          */
  21         private static function semaphoreKey($key)
  22         {
  23                 $temp = get_temppath();
  24
  25                 $file = $temp . '/' . $key . '.sem';
  26
  27                 if (!file_exists($file)) {
  28                         file_put_contents($file, $key);
  29                 }
  30
  31                 return ftok($file, 'f');
  32         }
  33
  34         /**
  35          * (@inheritdoc)
  36          */
  37         public function acquireLock($key, $timeout = 120, $ttl = Cache::FIVE_MINUTES)
  38         {
  39                 self::$semaphore[$key] = sem_get(self::semaphoreKey($key));
  40                 if (self::$semaphore[$key]) {
  41                         if (sem_acquire(self::$semaphore[$key], ($timeout == 0))) {
  42                                 $this->markAcquire($key);
  43                                 return true;
  44                         }
  45                 }
  46
  47                 return false;
  48         }
  49
  50         /**
  51          * (@inheritdoc)
  52          */
  53         public function releaseLock($key)
  54         {
  55                 if (empty(self::$semaphore[$key])) {
  56                         return false;
  57                 } else {
  58                         $success = @sem_release(self::$semaphore[$key]);
  59                         unset(self::$semaphore[$key]);
  60                         $this->markRelease($key);
  61                         return $success;
  62                 }
  63         }
  64
  65         /**
  66          * (@inheritdoc)
  67          */
  68         public function isLocked($key)
  69         {
  70                 return isset(self::$semaphore[$key]);
  71         }
  72 }