src/Core/Lock/SemaphoreLockDriver.php

   1 <?php
   2
   3 namespace Friendica\Core\Lock;
   4
   5 class SemaphoreLockDriver extends AbstractLockDriver
   6 {
   7         public function __construct()
   8         {
   9                 if (!function_exists('sem_get')) {
  10                         throw new \Exception('Semaphore lock not supported');
  11                 }
  12         }
  13
  14         /**
  15          * @brief Creates a semaphore key
  16          *
  17          * @param string $key Name of the lock
  18          *
  19          * @return integer the semaphore key
  20          */
  21         private static function semaphoreKey(string $key): int
  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          *
  36          * @brief Sets a lock for a given name
  37          *
  38          * @param string $key The Name of the lock
  39          * @param integer $timeout Seconds until we give up
  40          *
  41          * @return boolean Was the lock successful?
  42          */
  43         public function acquireLock(string $key, int $timeout = 120)
  44         {
  45                 $this->acquiredLocks[$key] = sem_get(self::semaphoreKey($key));
  46                 if ($this->acquiredLocks[$key]) {
  47                         return sem_acquire($this->acquiredLocks[$key], ($timeout == 0));
  48                 }
  49         }
  50
  51         /**
  52          * @brief Removes a lock if it was set by us
  53          *
  54          * @param string $key Name of the lock
  55          *
  56          * @return mixed
  57          */
  58         public function releaseLock(string $key)
  59         {
  60                 if (empty($this->acquiredLocks[$key])) {
  61                         return false;
  62                 } else {
  63                         $success = @sem_release($this->acquiredLocks[$key]);
  64                         unset($this->acquiredLocks[$key]);
  65                         return $success;
  66                 }
  67         }
  68 }