protected function checkFile(File $file, $deleteAfterCopy)
    {
        if (!$file->isReadable())
        {
            throw new InputFileNotReadableException('File ' . $file->getRealPath() . ' is not readable');
        }
        
        if ($deleteAfterCopy && !$file->isWritable())
        {
            throw new InputFileNotWritableException('File ' . $file->getRealPath() . ' is not writable');
        }
        
        return true;
    }