Simple exclusive locks in PHP

Lock.class.php

<?php
/* HOW TO USE

$lockFile = Lock::getLock('lock-name');
if (is_resource($lockFile)) {

  // you have a lock here, do whatever you want

  Lock::freeLock($lockFile);
}
else {
  // you could not get the lock. show a message or throw an exception or whatever
}
*/


class Lock
{
  /**
   * Creates a lockfile and acquires an exclusive lock on it.
   *
   * @param string $name The name of the lockfile.
   * @param boolean $blocking Block until lock becomes available (default: don't block, just fail)
   * @return mixed Returns the lockfile, or FALSE if a lock could not be acquired.
   */
  public static function getLock($name, $blocking = false)
  {
    if (!preg_match('/^[A-Za-z0-9\.\-_]+$/', $name))
    {
      throw new InvalidArgumentException('Invalid lock name: "' . $name . '"');
    }

    $filename = static::getLockDir() . '/' . $name;
    if (!preg_match('/\.lo?ck$/', $filename))
    {
      $filename .= '.lck';
    }
    if (!file_exists($filename))
    {
      file_put_contents($filename, '');
      chmod($filename, 0666); // if the file cant be opened for writing later, getting the lock will fail
    }
    $lockFile = fopen($filename, 'w+');
    if (!flock($lockFile, $blocking ? LOCK_EX : LOCK_EX|LOCK_NB))
    {
      fclose($lockFile);
      return false;
    }
    return $lockFile;
  }

  /**
   * Free a lock.
   *
   * @param resource $lockFile
   */
  public static function freeLock($lockFile)
  {
    if ($lockFile)
    {
      flock($lockFile, LOCK_UN);
      fclose($lockFile);
    }
  }

  public static function getLockDir()
  {
    return sys_get_temp_dir();
  }
}