src/Core/Lock/SemaphoreLockDriver.php

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