src/Core/Lock/DatabaseLockDriver.php

   1 <?php
   2
   3 namespace Friendica\Core\Lock;
   4
   5 use dba;
   6 use Friendica\Database\DBM;
   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 acquire($key, $timeout = 120)
  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` >= ?', $key, DateTimeFormat::utcNow()]);
  25
  26                         if (DBM::is_result($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                                                 $this->markAcquire($key);
  32                                         }
  33                                 }
  34                                 if (!$lock['locked']) {
  35                                         dba::update('locks', ['locked' => true, 'pid' => getmypid(), 'expires' => DateTimeFormat::utc('now + 300seconds')], ['name' => $key]);
  36                                         $got_lock = true;
  37                                         $this->markAcquire($key);
  38                                 }
  39                         } else {
  40                                 dba::insert('locks', ['name' => $key, 'locked' => true, 'pid' => getmypid(), 'expires' => DateTimeFormat::utc('now + 300seconds')]);
  41                                 $got_lock = true;
  42                                 $this->markAcquire($key);
  43                         }
  44
  45                         dba::unlock();
  46
  47                         if (!$got_lock && ($timeout > 0)) {
  48                                 usleep(rand(100000, 2000000));
  49                         }
  50                 } while (!$got_lock && ((time() - $start) < $timeout));
  51
  52                 return $got_lock;
  53         }
  54
  55         /**
  56          * (@inheritdoc)
  57          */
  58         public function release($key)
  59         {
  60                 dba::delete('locks', ['name' => $key, 'pid' => getmypid()]);
  61
  62                 $this->markRelease($key);
  63
  64                 return;
  65         }
  66
  67         /**
  68          * (@inheritdoc)
  69          */
  70         public function releaseAll()
  71         {
  72                 dba::delete('locks', ['pid' => getmypid()]);
  73
  74                 $this->acquiredLocks = [];
  75         }
  76
  77         /**
  78          * (@inheritdoc)
  79          */
  80         public function isLocked($key)
  81         {
  82                 $lock = dba::selectFirst('locks', ['locked'], ['`name` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
  83
  84                 if (DBM::is_result($lock)) {
  85                         return $lock['locked'] !== false;
  86                 } else {
  87                         return false;
  88                 }
  89         }
  90 }