protected function buildResourceWatcher($sourceDir, $destinationDir)
    {
        $fs = new Filesystem();
        $relativeDestination = rtrim($fs->makePathRelative($destinationDir, $sourceDir), '/');

        $finder = new Finder();
        $finder->files()
            ->name('*.*')
            ->in($sourceDir);

        if (false === strpos($relativeDestination, '..')) {
            $finder->exclude($relativeDestination);
        }

        $rc = new ResourceCacheMemory();
        $rw = new ResourceWatcher($rc);
        $rw->setFinder($finder);

        return $rw;
    }