--- /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\Filesystem;
+
+use Symfony\Component\Filesystem\Exception\IOException;
+
+/**
+ * LockHandler class provides a simple abstraction to lock anything by means of
+ * a file lock.
+ *
+ * A locked file is created based on the lock name when calling lock(). Other
+ * lock handlers will not be able to lock the same name until it is released
+ * (explicitly by calling release() or implicitly when the instance holding the
+ * lock is destroyed).
+ *
+ * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ * @author Romain Neutron <imprec@gmail.com>
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class LockHandler
+{
+ private $file;
+ private $handle;
+
+ /**
+ * @param string $name The lock name
+ * @param string|null $lockPath The directory to store the lock. Default values will use temporary directory
+ *
+ * @throws IOException If the lock directory could not be created or is not writable
+ */
+ public function __construct($name, $lockPath = null)
+ {
+ $lockPath = $lockPath ?: sys_get_temp_dir();
+
+ if (!is_dir($lockPath)) {
+ $fs = new Filesystem();
+ $fs->mkdir($lockPath);
+ }
+
+ if (!is_writable($lockPath)) {
+ throw new IOException(sprintf('The directory "%s" is not writable.', $lockPath), 0, null, $lockPath);
+ }
+
+ $this->file = sprintf('%s/sf.%s.%s.lock', $lockPath, preg_replace('/[^a-z0-9\._-]+/i', '-', $name), hash('sha256', $name));
+ }
+
+ /**
+ * Lock the resource.
+ *
+ * @param bool $blocking wait until the lock is released
+ *
+ * @return bool Returns true if the lock was acquired, false otherwise
+ *
+ * @throws IOException If the lock file could not be created or opened
+ */
+ public function lock($blocking = false)
+ {
+ if ($this->handle) {
+ return true;
+ }
+
+ // Silence error reporting
+ set_error_handler(function () {});
+
+ if (!$this->handle = fopen($this->file, 'r')) {
+ if ($this->handle = fopen($this->file, 'x')) {
+ chmod($this->file, 0444);
+ } elseif (!$this->handle = fopen($this->file, 'r')) {
+ usleep(100); // Give some time for chmod() to complete
+ $this->handle = fopen($this->file, 'r');
+ }
+ }
+ restore_error_handler();
+
+ if (!$this->handle) {
+ $error = error_get_last();
+ throw new IOException($error['message'], 0, null, $this->file);
+ }
+
+ // On Windows, even if PHP doc says the contrary, LOCK_NB works, see
+ // https://bugs.php.net/54129
+ if (!flock($this->handle, LOCK_EX | ($blocking ? 0 : LOCK_NB))) {
+ fclose($this->handle);
+ $this->handle = null;
+
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Release the resource.
+ */
+ public function release()
+ {
+ if ($this->handle) {
+ flock($this->handle, LOCK_UN | LOCK_NB);
+ fclose($this->handle);
+ $this->handle = null;
+ }
+ }
+}