--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Console\Command;
+
+use Symfony\Component\Console\Exception\LogicException;
+use Symfony\Component\Console\Exception\RuntimeException;
+use Symfony\Component\Filesystem\LockHandler;
+
+/**
+ * Basic lock feature for commands.
+ *
+ * @author Geoffrey Brier <geoffrey.brier@gmail.com>
+ */
+trait LockableTrait
+{
+ private $lockHandler;
+
+ /**
+ * Locks a command.
+ *
+ * @return bool
+ */
+ private function lock($name = null, $blocking = false)
+ {
+ if (!class_exists(LockHandler::class)) {
+ throw new RuntimeException('To enable the locking feature you must install the symfony/filesystem component.');
+ }
+
+ if (null !== $this->lockHandler) {
+ throw new LogicException('A lock is already in place.');
+ }
+
+ $this->lockHandler = new LockHandler($name ?: $this->getName());
+
+ if (!$this->lockHandler->lock($blocking)) {
+ $this->lockHandler = null;
+
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Releases the command lock if there is one.
+ */
+ private function release()
+ {
+ if ($this->lockHandler) {
+ $this->lockHandler->release();
+ $this->lockHandler = null;
+ }
+ }
+}