qint64 get_size()
{   
    QString link  =  url -> text();
    std::cout << qPrintable(link) << std::endl;
    QNetworkAccessManager manager;
    QEventLoop loop;
    QNetworkReply  * reply  =  manager.head(QNetworkRequest(link));
    QObject::connect(reply,SIGNAL(finished()),  & loop, SLOT(quit()), Qt::DirectConnection);
    loop.exec();
    QVariant var  =  reply -> header(QNetworkRequest::ContentLengthHeader);
    delete reply;
    qint64 size  =  var.toLongLong();
    std::cout << size << std::endl;
     return  size;
}