qtcpserver.cpp

奇趣公司比较新的qt/emd版本

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//#define QTCPSERVER_DEBUG

/*! \class QTcpServer

    \brief The QTcpServer class provides a TCP-based server.

    \reentrant
    \ingroup io
    \module network

    This class makes it possible to accept incoming TCP connections.
    You can specify the port or have QTcpServer pick one
    automatically. You can listen on a specific address or on all the
    machine's addresses.

    Call listen() to have the server listen for incoming connections.
    The newConnection() signal is then emitted each time a client
    connects to the server.

    Call nextPendingConnection() to accept the pending connection as
    a connected QTcpSocket. The function returns a pointer to a
    QTcpSocket in QAbstractSocket::ConnectedState that you can use for
    communicating with the client.

    If an error occurs, serverError() returns the type of error, and
    errorString() can be called to get a human readable description of
    what happened.

    When listening for connections, the address and port on which the
    server is listening are available as serverAddress() and
    serverPort().

    Calling close() makes QTcpServer stop listening for incoming
    connections.

    Although QTcpServer is mostly designed for use with an event
    loop, it's possible to use it without one. In that case, you must
    use waitForNewConnection(), which blocks until either a
    connection is available or a timeout expires.

    \sa QTcpSocket, {Fortune Server Example}, {Threaded Fortune Server Example},
        {Loopback Example}, {Torrent Example}
*/

/*! \fn void QTcpServer::newConnection()

    This signal is emitted every time a new connection is available.

    \sa hasPendingConnections(), nextPendingConnection()
*/

#include "private/qobject_p.h"
#include "qalgorithms.h"
#include "qhostaddress.h"
#include "qlist.h"
#include "qpointer.h"
#include "qnativesocketengine_p.h"
#include "qtcpserver.h"
#include "qtcpsocket.h"
#include "qnetworkproxy.h"


#define Q_CHECK_SOCKETENGINE(returnValue) do { \
    if (!d->socketEngine) { \
        return returnValue; \
    } } while (0)

class QTcpServerPrivate : public QObjectPrivate, public QAbstractSocketEngineReceiver
{
    Q_DECLARE_PUBLIC(QTcpServer)
public:
    QTcpServerPrivate();
    ~QTcpServerPrivate();

    QList<QTcpSocket *> pendingConnections;

    quint16 port;
    QHostAddress address;

    QAbstractSocket::SocketState state;
    QAbstractSocketEngine *socketEngine;

    QAbstractSocket::SocketError serverSocketError;
    QString serverSocketErrorString;

    int maxConnections;

#ifndef QT_NO_NETWORKPROXY
    QNetworkProxy *proxy;
#endif

    // from QAbstractSocketEngineReceiver
    void readNotification();
    inline void writeNotification() {}
    inline void exceptionNotification() {}
    inline void proxyAuthenticationRequired(const QNetworkProxy &, QAuthenticator *) {}

};

/*! \internal
*/
QTcpServerPrivate::QTcpServerPrivate()
 : port(0)
 , state(QAbstractSocket::UnconnectedState)
 , socketEngine(0)
 , serverSocketError(QAbstractSocket::UnknownSocketError)
 , maxConnections(30)
#ifndef QT_NO_NETWORKPROXY
 , proxy(0)
#endif
{
}

/*! \internal
*/
QTcpServerPrivate::~QTcpServerPrivate()
{
#ifndef QT_NO_NETWORKPROXY
     delete proxy;
#endif
}

/*! \internal
*/
void QTcpServerPrivate::readNotification()
{
    Q_Q(QTcpServer);
    for (;;) {
        if (pendingConnections.count() >= maxConnections) {
#if defined (QTCPSERVER_DEBUG)
            qDebug("QTcpServerPrivate::_q_processIncomingConnection() too many connections");
#endif
            if (socketEngine->isReadNotificationEnabled())
                socketEngine->setReadNotificationEnabled(false);
            return;
        }

        int descriptor = socketEngine->accept();
        if (descriptor == -1)
            break;
#if defined (QTCPSERVER_DEBUG)
        qDebug("QTcpServerPrivate::_q_processIncomingConnection() accepted socket %i", descriptor);
#endif
        q->incomingConnection(descriptor);

        QPointer<QTcpServer> that = q;
        emit q->newConnection();
        if (!that || !q->isListening())
            return;
    }
}

/*!
    Constructs a QTcpServer object.

    \a parent is passed to the QObject constructor.

    \sa listen(), setSocketDescriptor()
*/
QTcpServer::QTcpServer(QObject *parent)
    : QObject(*new QTcpServerPrivate, parent)
{
}

/*!
    Destroys the QTcpServer object. If the server is listening for
    connections, the socket is automatically closed.

    Any client \l{QTcpSocket}s that are still connected must either
    disconnect or be reparented before the server is deleted.

    \sa close()
*/
QTcpServer::~QTcpServer()
{
    close();
}

/*!
    Tells the server to listen for incoming connections on address \a
    address and port \a port. If \a port is 0, a port is chosen
    automatically. If \a address is QHostAddress::Any, the server
    will listen on all network interfaces.

    Returns true on success; otherwise returns false.

    \sa isListening()
*/
bool QTcpServer::listen(const QHostAddress &address, quint16 port)
{
    Q_D(QTcpServer);
    if (d->state == QAbstractSocket::ListeningState) {
        qWarning("QTcpServer::listen() called when already listening");
        return false;
    }

    QAbstractSocket::NetworkLayerProtocol proto = address.protocol();
#if defined(QT_NO_IPV6)
    if (proto == QAbstractSocket::IPv6Protocol) {
        // If we have no IPv6 support, then we will not be able to
        // listen on an IPv6 interface.
        d->serverSocketError = QAbstractSocket::UnsupportedSocketOperationError;
        d->serverSocketErrorString = tr("Socket operation unsupported");
        return false;
    }
#endif

    if (d->socketEngine)
        delete d->socketEngine;
    d->socketEngine = QAbstractSocketEngine::createSocketEngine(address, QAbstractSocket::TcpSocket, this);
    if (!d->socketEngine->initialize(QAbstractSocket::TcpSocket, proto)) {
        d->serverSocketError = d->socketEngine->error();
        d->serverSocketErrorString = d->socketEngine->errorString();
        return false;
    }

#if defined(Q_OS_UNIX)
    // Under Unix, we want to be able to bind to the port, even if a socket on
    // the same address-port is in TIME_WAIT. Under Windows this is possible
    // anyway -- furthermore, the meaning of reusable on Windows is different:
    // it means that you can use the same address-port for multiple listening
    // sockets.
    // Don't abort though if we can't set that option. For example the socks
    // engine doesn't support that option, but that shouldn't prevent us from
    // trying to bind/listen.
    d->socketEngine->setOption(QAbstractSocketEngine::AddressReusable, 1);
#endif

    if (!d->socketEngine->bind(address, port)) {
        d->serverSocketError = d->socketEngine->error();
        d->serverSocketErrorString = d->socketEngine->errorString();
        return false;
    }

    if (!d->socketEngine->listen()) {
        d->serverSocketError = d->socketEngine->error();
        d->serverSocketErrorString = d->socketEngine->errorString();
        return false;
    }

    d->socketEngine->setReceiver(d);
    d->socketEngine->setReadNotificationEnabled(true);

    d->state = QAbstractSocket::ListeningState;
    d->address = d->socketEngine->localAddress();
    d->port = d->socketEngine->localPort();

#if defined (QTCPSERVER_DEBUG)
    qDebug("QTcpServer::listen(%i, \"%s\") == true (listening on port %i)", port,
           address.toString().toLatin1().constData(), d->socketEngine->localPort());
#endif
    return true;
}

/*!
    Returns true if the server is currently listening for incoming
    connections; otherwise returns false.

    \sa listen()
*/
bool QTcpServer::isListening() const
{
    Q_D(const QTcpServer);
    Q_CHECK_SOCKETENGINE(false);
    return d->socketEngine->state() == QAbstractSocket::ListeningState;
}

/*!