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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\Console\Command;
  13  
  14  use Symfony\Component\Console\Exception\LogicException;
  15  use Symfony\Component\Console\Exception\RuntimeException;
  16  use Symfony\Component\Lock\Factory;
  17  use Symfony\Component\Lock\Lock;
  18  use Symfony\Component\Lock\Store\FlockStore;
  19  use Symfony\Component\Lock\Store\SemaphoreStore;
  20  
  21  /**
  22   * Basic lock feature for commands.
  23   *
  24   * @author Geoffrey Brier <geoffrey.brier@gmail.com>
  25   */
  26  trait LockableTrait
  27  {
  28      /** @var Lock */
  29      private $lock;
  30  
  31      /**
  32       * Locks a command.
  33       *
  34       * @return bool
  35       */
  36      private function lock($name = null, $blocking = false)
  37      {
  38          if (!class_exists(SemaphoreStore::class)) {
  39              throw new RuntimeException('To enable the locking feature you must install the symfony/lock component.');
  40          }
  41  
  42          if (null !== $this->lock) {
  43              throw new LogicException('A lock is already in place.');
  44          }
  45  
  46          if (SemaphoreStore::isSupported($blocking)) {
  47              $store = new SemaphoreStore();
  48          } else {
  49              $store = new FlockStore();
  50          }
  51  
  52          $this->lock = (new Factory($store))->createLock($name ?: $this->getName());
  53          if (!$this->lock->acquire($blocking)) {
  54              $this->lock = null;
  55  
  56              return false;
  57          }
  58  
  59          return true;
  60      }
  61  
  62      /**
  63       * Releases the command lock if there is one.
  64       */
  65      private function release()
  66      {
  67          if ($this->lock) {
  68              $this->lock->release();
  69              $this->lock = null;
  70          }
  71      }
  72  }