[완료] Qt 네트워크 프로그래밍 질문 좀 드릴게요~

#include <QApplication>
#include <QtCore>
 
#include <stdlib.h>
 
#include "server.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Server server;
#ifdef Q_OS_SYMBIAN
    server.showMaximized();
#else
    server.show();
#endif
    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
    return server.exec();
}

#ifndef SERVER_H
#define SERVER_H
 
#include <QDialog>
 
QT_BEGIN_NAMESPACE
class QLabel;
class QPushButton;
class QTcpServer;
class QNetworkSession;
QT_END_NAMESPACE
 
class Server : public QDialog
{
    Q_OBJECT
 
public:
    Server(QWidget *parent = 0);
 
private slots:
    void sessionOpened();
    void sendFortune();
 
private:
    QLabel *statusLabel;
    QPushButton *quitButton;
    QTcpServer *tcpServer;
    QStringList fortunes;
    QNetworkSession *networkSession;
};
 
#endif

#include <QtGui>
#include <QtNetwork>
 
#include <stdlib.h>
 
#include "server.h"
 
Server::Server(QWidget *parent)
:   QDialog(parent), tcpServer(0), networkSession(0)
{
    statusLabel = new QLabel;
    quitButton = new QPushButton(tr("Quit"));
    quitButton->setAutoDefault(false);
 
    QNetworkConfigurationManager manager;  // <------------ 여기서부터 (1)
    if (manager.capabilities() & QNetworkConfigurationManager::NetworkSessionRequired) {
		// Get saved network configuration
		QSettings settings(QSettings::UserScope, QLatin1String("Trolltech"));
		settings.beginGroup(QLatin1String("QtNetwork"));
		const QString id = settings.value(QLatin1String("DefaultNetworkConfiguration")).toString();
		settings.endGroup();
 
		// If the saved network configuration is not currently discovered use the system default
		QNetworkConfiguration config = manager.configurationFromIdentifier(id);
		if ((config.state() & QNetworkConfiguration::Discovered) !=
			QNetworkConfiguration::Discovered) {
			config = manager.defaultConfiguration();
		}
 
		networkSession = new QNetworkSession(config, this);
		connect(networkSession, SIGNAL(opened()), this, SLOT(sessionOpened()));
 
		statusLabel->setText(tr("Opening network session."));
		networkSession->open();     // <------------ 여기까지 (1)
    } else {
        sessionOpened();
    }
 
        fortunes << tr("You've been leading a dog's life. Stay off the furniture.")
                 << tr("You've got to think about tomorrow.")
                 << tr("You will be surprised by a loud noise.")
                 << tr("You will feel hungry again in another hour.")
                 << tr("You might have mail.")
                 << tr("You cannot kill time without injuring eternity.")
                 << tr("Computers are not intelligent. They only think they are.");
 
        connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
        connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendFortune()));
 
        QHBoxLayout *buttonLayout = new QHBoxLayout;
        buttonLayout->addStretch(1);
        buttonLayout->addWidget(quitButton);
        buttonLayout->addStretch(1);
 
        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout->addWidget(statusLabel);
        mainLayout->addLayout(buttonLayout);
        setLayout(mainLayout);
 
        setWindowTitle(tr("Fortune Server"));
}
 
void Server::sessionOpened()
{
    // Save the used configuration
    if (networkSession) {   // <------------ 여기서부터 (2)
        QNetworkConfiguration config = networkSession->configuration();
        QString id;
        if (config.type() == QNetworkConfiguration::UserChoice)
            id = networkSession->sessionProperty(QLatin1String("UserChoiceConfiguration")).toString();
        else
            id = config.identifier();
 
        QSettings settings(QSettings::UserScope, QLatin1String("Trolltech"));
        settings.beginGroup(QLatin1String("QtNetwork"));
        settings.setValue(QLatin1String("DefaultNetworkConfiguration"), id);
        settings.endGroup();
    }    // <------------ 여기까지 (2)
 
    tcpServer = new QTcpServer(this);
    if (!tcpServer->listen()) {
        QMessageBox::critical(this, tr("Fortune Server"),
                              tr("Unable to start the server: %1.")
                              .arg(tcpServer->errorString()));
        close();
        return;
    }
 
    QString ipAddress;
	QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
	// use the first non-localhost IPv4 address
    for (int i = 0; i < ipAddressesList.size(); ++i) {
        if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
            ipAddressesList.at(i).toIPv4Address()) {
            ipAddress = ipAddressesList.at(i).toString();
            break;
        }
    }
    // if we did not find one, use IPv4 localhost
    if (ipAddress.isEmpty())
        ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
    statusLabel->setText(tr("The server is running on\n\nIP: %1\nport: %2\n\n"
                            "Run the Fortune Client example now.")
                         .arg(ipAddress).arg(tcpServer->serverPort()));
}
 
void Server::sendFortune()
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_0);
 
    out << (quint16)0;
    out << fortunes.at(qrand() % fortunes.size());
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));
 
    QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
    connect(clientConnection, SIGNAL(disconnected()),
            clientConnection, SLOT(deleteLater()));
 
    clientConnection->write(block);
    clientConnection->disconnectFromHost();
}