src/Core/Lock/DatabaseLockDriver.php

   1 <?php
   2
   3 namespace Friendica\Core\Lock;
   4
   5 use Friendica\Core\Cache;
   6 use Friendica\Database\DBA;
   7 use Friendica\Util\DateTimeFormat;
   8
   9 /**
  10  * Locking driver that stores the locks in the database
  11  */
  12 class DatabaseLockDriver extends AbstractLockDriver
  13 {
  14         /**
  15          * (@inheritdoc)
  16          */
  17         public function acquireLock($key, $timeout = 120, $ttl = Cache::FIVE_MINUTES)
  18         {
  19                 $got_lock = false;
  20                 $start = time();
  21
  22                 do {
  23                         DBA::lock('locks');
  24                         $lock = DBA::selectFirst('locks', ['locked', 'pid'], ['`name` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
  25
  26                         if (DBA::isResult($lock)) {
  27                                 if ($lock['locked']) {
  28                                         // We want to lock something that was already locked by us? So we got the lock.
  29                                         if ($lock['pid'] == getmypid()) {
  30                                                 $got_lock = true;
  31                                         }
  32                                 }
  33                                 if (!$lock['locked']) {
  34                                         DBA::update('locks', ['locked' => true, 'pid' => getmypid(), 'expires' => DateTimeFormat::utc('now + ' . $ttl . 'seconds')], ['name' => $key]);
  35                                         $got_lock = true;
  36                                 }
  37                         } else {
  38                                 DBA::insert('locks', ['name' => $key, 'locked' => true, 'pid' => getmypid(), 'expires' => DateTimeFormat::utc('now + ' . $ttl . 'seconds')]);
  39                                 $got_lock = true;
  40                                 $this->markAcquire($key);
  41                         }
  42
  43                         DBA::unlock();
  44
  45                         if (!$got_lock && ($timeout > 0)) {
  46                                 usleep(rand(100000, 2000000));
  47                         }
  48                 } while (!$got_lock && ((time() - $start) < $timeout));
  49
  50                 return $got_lock;
  51         }
  52
  53         /**
  54          * (@inheritdoc)
  55          */
  56         public function releaseLock($key)
  57         {
  58                 DBA::delete('locks', ['name' => $key, 'pid' => getmypid()]);
  59
  60                 $this->markRelease($key);
  61
  62                 return;
  63         }
  64
  65         /**
  66          * (@inheritdoc)
  67          */
  68         public function releaseAll()
  69         {
  70                 DBA::delete('locks', ['pid' => getmypid()]);
  71
  72                 $this->acquiredLocks = [];
  73         }
  74
  75         /**
  76          * (@inheritdoc)
  77          */
  78         public function isLocked($key)
  79         {
  80                 $lock = DBA::selectFirst('locks', ['locked'], ['`name` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
  81
  82                 if (DBA::isResult($lock)) {
  83                         return $lock['locked'] !== false;
  84                 } else {
  85                         return false;
  86                 }
  87         }
  88 }