qabstractsocket.cpp

奇趣公司比较新的qt/emd版本

        qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), connecting to %s:%i",
               host.toString().toLatin1().constData(), port);
#endif

#if defined(QT_NO_IPV6)
        if (host.protocol() == QAbstractSocket::IPv6Protocol) {
            // If we have no IPv6 support, then we will not be able to
            // connect. So we just pretend we didn't see this address.
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), skipping IPv6 entry");
#endif
            continue;
        }
#endif

        if (!initSocketLayer(host, q->socketType())) {
            // hope that the next address is better
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), failed to initialize sock layer");
#endif
            continue;
        }

        // Tries to connect to the address. If it succeeds immediately
        // (localhost address on BSD or any UDP connect), emit
        // connected() and return.
        if (socketEngine->connectToHost(host, port)) {
            fetchConnectionParameters();
            return;
        }

        // Check that we're in delayed connection state. If not, try
        // the next address
        if (socketEngine->state() != QAbstractSocket::ConnectingState) {
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), connection failed (%s)",
                   socketEngine->errorString().toLatin1().constData());
#endif
            continue;
        }

        // Start the connect timer.
        if (threadData->eventDispatcher) {
            if (!connectTimer) {
                connectTimer = new QTimer(q);
                QObject::connect(connectTimer, SIGNAL(timeout()),
                                 q, SLOT(_q_abortConnectionAttempt()));
            }
            connectTimer->start(QT_CONNECT_TIMEOUT);
        }

        // Wait for a write notification that will eventually call
        // _q_testConnection().
        socketEngine->setWriteNotificationEnabled(true);
        break;
    } while (state != QAbstractSocket::ConnectedState);
}

/*! \internal

    Tests if a connection has been established. If it has, connected()
    is emitted. Otherwise, _q_connectToNextAddress() is invoked.
*/
void QAbstractSocketPrivate::_q_testConnection()
{
    if (socketEngine) {
        if (socketEngine->state() != QAbstractSocket::ConnectedState) {
            // Try connecting if we're not already connected.
            if (!socketEngine->connectToHost(host, port)) {
                if (socketEngine->error() == QAbstractSocket::UnfinishedSocketOperationError) {
                    // Connection in progress; wait for the next notification.
                    socketEngine->setWriteNotificationEnabled(true);
                    return;
                }
            }
        }

        if (threadData->eventDispatcher) {
            if (connectTimer)
                connectTimer->stop();
        }

        if (socketEngine->state() == QAbstractSocket::ConnectedState) {
            // Fetch the parameters if our connection is completed;
            // otherwise, fall out and try the next address.
            fetchConnectionParameters();
            return;
        }

        // don't retry the other addresses if we couldn't authenticate to the proxy.
        if (socketEngine->error() == QAbstractSocket::ProxyAuthenticationRequiredError)
            addresses.clear();
    }

    if (threadData->eventDispatcher) {
        if (connectTimer)
            connectTimer->stop();
    }

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::_q_testConnection() connection failed,"
           " checking for alternative addresses");
#endif
    _q_connectToNextAddress();
}

/*! \internal

    This function is called after a certain number of seconds has
    passed while waiting for a connection. It simply tests the
    connection, and continues to the next address if the connection
    failed.
*/
void QAbstractSocketPrivate::_q_abortConnectionAttempt()
{
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::_q_abortConnectionAttempt() (timed out)");
#endif
    if (socketEngine) {
        socketEngine->setWriteNotificationEnabled(false);

        if (socketEngine->isValid())
            _q_testConnection();
    }
}

/*! \internal

    Reads data from the socket layer into the read buffer. Returns
    true on success; otherwise false.
*/
bool QAbstractSocketPrivate::readFromSocket()
{
    Q_Q(QAbstractSocket);
    // Find how many bytes we can read from the socket layer.
    qint64 bytesToRead = socketEngine->bytesAvailable();
#ifdef Q_OS_LINUX
    if (bytesToRead > 0) // ### See setSocketDescriptor()
        bytesToRead += addToBytesAvailable;
#endif
    if (bytesToRead == 0) {
        // Under heavy load, certain conditions can trigger read notifications
        // for socket notifiers on which there is no activity. If we continue
        // to read 0 bytes from the socket, we will trigger behavior similar
        // to that which signals a remote close. When we hit this condition,
        // we try to read 4k of data from the socket, which will give us either
        // an EAGAIN/EWOULDBLOCK if the connection is alive (i.e., the remote
        // host has _not_ disappeared).
        bytesToRead = 4096;
    }
    if (readBufferMaxSize && bytesToRead > (readBufferMaxSize - readBuffer.size()))
        bytesToRead = readBufferMaxSize - readBuffer.size();

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::readFromSocket() about to read %d bytes",
           int(bytesToRead));
#endif

    // Read from the socket, store data in the read buffer.
    char *ptr = readBuffer.reserve(bytesToRead);
    qint64 readBytes = socketEngine->read(ptr, bytesToRead);
    if (readBytes == -2) {
        // No bytes currently available for reading.
        readBuffer.chop(bytesToRead);
        return true;
    }
    readBuffer.chop(int(bytesToRead - (readBytes < 0 ? qint64(0) : readBytes)));
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::readFromSocket() got %d bytes, buffer size = %d",
           int(readBytes), readBuffer.size());
#endif

    if (!socketEngine->isValid()) {
        socketError = socketEngine->error();
        q->setErrorString(socketEngine->errorString());
        emit q->error(socketError);
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::readFromSocket() read failed: %s",
               q->errorString().toLatin1().constData());
#endif
        resetSocketLayer();
        return false;
    }

    return true;
}

/*! \internal

    Sets up the the internal state after the connection has succeeded.
*/
void QAbstractSocketPrivate::fetchConnectionParameters()
{
    Q_Q(QAbstractSocket);

    peerName = hostName;
    if (socketEngine) {
        socketEngine->setReadNotificationEnabled(true);
        socketEngine->setWriteNotificationEnabled(true);
        localPort = socketEngine->localPort();
        peerPort = socketEngine->peerPort();
        localAddress = socketEngine->localAddress();
        peerAddress = socketEngine->peerAddress();
        cachedSocketDescriptor = socketEngine->socketDescriptor();
    }

    state = QAbstractSocket::ConnectedState;
    emit q->stateChanged(state);
    emit q->connected();

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::fetchConnectionParameters() connection to %s:%i established",
           host.toString().toLatin1().constData(), port);
#endif
}

/*! \internal

    Constructs a new abstract socket of type \a socketType. The \a
    parent argument is passed to QObject's constructor.
*/
QAbstractSocket::QAbstractSocket(SocketType socketType,
                                 QAbstractSocketPrivate &dd, QObject *parent)
    : QIODevice(dd, parent)
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::QAbstractSocket(%sSocket, QAbstractSocketPrivate == %p, parent == %p)",
           socketType == TcpSocket ? "Tcp" : socketType == UdpSocket
           ? "Udp" : "Unknown", &dd, parent);
#endif
    d->socketType = socketType;
}

/*!
    Creates a new abstract socket of type \a socketType. The \a
    parent argument is passed to QObject's constructor.

    \sa socketType(), QTcpSocket, QUdpSocket
*/
QAbstractSocket::QAbstractSocket(SocketType socketType, QObject *parent)
    : QIODevice(*new QAbstractSocketPrivate, parent)
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::QAbstractSocket(%p)", parent);
#endif
    d->socketType = socketType;
}

/*!
    Destroys the socket.
*/
QAbstractSocket::~QAbstractSocket()
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::~QAbstractSocket()");
#endif
    if (d->state != UnconnectedState)
        abort();
}

/*!
    Returns true if the socket is valid and ready for use; otherwise
    returns false.

    \bold{Note:} The socket's state must be ConnectedState before reading and
    writing can occur.

    \sa state()
*/
bool QAbstractSocket::isValid() const
{
    return d_func()->socketEngine ? d_func()->socketEngine->isValid() : isOpen();
}

/*!
    Attempts to make a connection to \a hostName on the given \a port.

    The socket is opened in the given \a openMode and first enters
    HostLookupState, then performs a host name lookup of \a hostName.
    If the lookup succeeds, hostFound() is emitted and QAbstractSocket
    enters ConnectingState. It then attempts to connect to the address
    or addresses returned by the lookup. Finally, if a connection is
    established, QAbstractSocket enters ConnectedState and
    emits connected().

    At any point, the socket can emit error() to signal that an error
    occurred.

    \a hostName may be an IP address in string form (e.g.,
    "43.195.83.32"), or it may be a host name (e.g.,
    "www.trolltech.com"). QAbstractSocket will do a lookup only if
    required. \a port is in native byte order.

    \sa state(), peerName(), peerAddress(), peerPort(), waitForConnected()
*/
void QAbstractSocket::connectToHost(const QString &hostName, quint16 port,
                                    OpenMode openMode)
{
    QMetaObject::invokeMethod(this, "connectToHostImplementation",
                              Q_ARG(QString, hostName),
                              Q_ARG(quint16, port),
                              Q_ARG(OpenMode, openMode));
}

/*!
    \since 4.1

    Contains the implementation of connectToHost().

    Attempts to make a connection to \a hostName on the given \a
    port. The socket is opened in the given \a openMode.
*/
void QAbstractSocket::connectToHostImplementation(const QString &hostName, quint16 port,
                                                  OpenMode openMode)
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::connectToHost(\"%s\", %i, %i)...", hostName.toLatin1().constData(), port,
           (int) openMode);
#endif

    if (d->state == ConnectedState || d->state == ConnectingState) {
        qWarning("QAbstractSocket::connectToHost() called when already connecting/connected");
        return;
    }

    d->hostName = hostName;
    d->port = port;
    d->state = HostLookupState;
    d->readBuffer.clear();
    d->writeBuffer.clear();
    d->closeCalled = false;
    d->localPort = 0;
    d->peerPort = 0;
    d->localAddress.clear();
    d->peerAddress.clear();
    d->peerName = hostName;
#ifdef Q_OS_LINUX
    // ### See setSocketDescriptor().
    d->addToBytesAvailable = 0;
#endif
    if (d->hostLookupId != -1) {
        QHostInfo::abortHostLookup(d->hostLookupId);
        d->hostLookupId = -1;
    }

    if (!d_func()->isBuffered)
        openMode |= QAbstractSocket::Unbuffered;
    setOpenMode(openMode);
    emit stateChanged(d->state);

    QHostAddress temp;
    if (temp.setAddress(hostName)) {
        QHostInfo info;
        info.setAddresses(QList<QHostAddress>() << temp);
        d->_q_startConnecting(info);
    } else {
        if (d->threadData->eventDispatcher)
            d->hostLookupId = QHostInfo::lookupHost(hostName, this, SLOT(_q_startConnecting(QHostInfo)));
    }

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::connectToHost(\"%s\", %i) == %s%s", hostName.toLatin1().constData(), port,
           (d->state == ConnectedState) ? "true" : "false",
           (d->state == ConnectingState || d->state == HostLookupState)
           ? " (connection in progress)" : "");
#endif
}

/*! \overload

    Attempts to make a connection to \a address on port \a port.
*/
void QAbstractSocket::connectToHost(const QHostAddress &address, quint16 port,
                                    OpenMode openMode)
{
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::connectToHost([%s], %i, %i)...",
           address.toString().toLatin1().constData(), port, (int) openMode);
#endif
    connectToHost(address.toString(), port, openMode);
}

/*!
    Returns the number of bytes that are waiting to be written. The
    bytes are written when control goes back to the event loop or
    when flush() is called.

    \sa bytesAvailable(), flush()
*/
qint64 QAbstractSocket::bytesToWrite() const
{
    Q_D(const QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)