qabstractsocket.cpp

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//#define QABSTRACTSOCKET_DEBUG

#include "qabstractsocket.h"
#include "qabstractsocket_p.h"

#include "private/qhostinfo_p.h"
#include "private/qnetworksession_p.h"

#include <qabstracteventdispatcher.h>
#include <qhostaddress.h>
#include <qhostinfo.h>
#include <qmetaobject.h>
#include <qpointer.h>
#include <qtimer.h>
#include <qelapsedtimer.h>
#include <qscopedvaluerollback.h>

#ifndef QT_NO_OPENSSL
#include <QtNetwork/qsslsocket.h>
#endif

#include <private/qthread_p.h>

#ifdef QABSTRACTSOCKET_DEBUG
#include <qdebug.h>
#endif

#include <time.h>

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

#ifndef QABSTRACTSOCKET_BUFFERSIZE
#define QABSTRACTSOCKET_BUFFERSIZE 32768
#endif
#define QT_CONNECT_TIMEOUT 30000
#define QT_TRANSFER_TIMEOUT 120000

QT_BEGIN_NAMESPACE

#if defined QABSTRACTSOCKET_DEBUG
QT_BEGIN_INCLUDE_NAMESPACE
#include <qstring.h>
#include <ctype.h>
QT_END_INCLUDE_NAMESPACE

/*
    Returns a human readable representation of the first \a len
    characters in \a data.
*/
static QByteArray qt_prettyDebug(const char *data, int len, int maxLength)
{
    if (!data) return "(null)";
    QByteArray out;
    for (int i = 0; i < len; ++i) {
        char c = data[i];
        if (isprint(int(uchar(c)))) {
            out += c;
        } else switch (c) {
        case '\n': out += "\\n"; break;
        case '\r': out += "\\r"; break;
        case '\t': out += "\\t"; break;
        default:
            QString tmp;
            tmp.sprintf("\\%o", c);
            out += tmp.toLatin1();
        }
    }

    if (len < maxLength)
        out += "...";

    return out;
}
#endif

static bool isProxyError(QAbstractSocket::SocketError error)
{
    switch (error) {
    case QAbstractSocket::ProxyAuthenticationRequiredError:
    case QAbstractSocket::ProxyConnectionRefusedError:
    case QAbstractSocket::ProxyConnectionClosedError:
    case QAbstractSocket::ProxyConnectionTimeoutError:
    case QAbstractSocket::ProxyNotFoundError:
    case QAbstractSocket::ProxyProtocolError:
        return true;
    default:
        return false;
    }
}

QAbstractSocketPrivate::QAbstractSocketPrivate()
    : readSocketNotifierCalled(false),
      readSocketNotifierState(false),
      readSocketNotifierStateSet(false),
      emittedReadyRead(false),
      emittedBytesWritten(false),
      abortCalled(false),
      closeCalled(false),
      pendingClose(false),
      port(0),
      localPort(0),
      peerPort(0),
      socketEngine(0),
      cachedSocketDescriptor(-1),
      readBufferMaxSize(0),
      readBuffer(QABSTRACTSOCKET_BUFFERSIZE),
      writeBuffer(QABSTRACTSOCKET_BUFFERSIZE),
      isBuffered(false),
      blockingTimeout(30000),
      connectTimer(0),
      disconnectTimer(0),
      connectTimeElapsed(0),
      hostLookupId(-1),
      socketType(QAbstractSocket::UnknownSocketType),
      state(QAbstractSocket::UnconnectedState),
      socketError(QAbstractSocket::UnknownSocketError)
{
}

QAbstractSocketPrivate::~QAbstractSocketPrivate()
{
}

void QAbstractSocketPrivate::resetSocketLayer()
{
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::resetSocketLayer()");
#endif

    if (socketEngine) {
        socketEngine->close();
        socketEngine->disconnect();
        delete socketEngine;
        socketEngine = 0;
        cachedSocketDescriptor = -1;
    }
    if (connectTimer)
        connectTimer->stop();
    if (disconnectTimer)
        disconnectTimer->stop();
}

bool QAbstractSocketPrivate::initSocketLayer(QAbstractSocket::NetworkLayerProtocol protocol)
{
#ifdef QT_NO_NETWORKPROXY
    // this is here to avoid a duplication of the call to createSocketEngine below
    static const QNetworkProxy &proxyInUse = *(QNetworkProxy *)0;
#endif

    Q_Q(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    QString typeStr;
    if (q->socketType() == QAbstractSocket::TcpSocket) typeStr = QLatin1String("TcpSocket");
    else if (q->socketType() == QAbstractSocket::UdpSocket) typeStr = QLatin1String("UdpSocket");
    else typeStr = QLatin1String("UnknownSocketType");
    QString protocolStr;
    if (protocol == QAbstractSocket::IPv4Protocol) protocolStr = QLatin1String("IPv4Protocol");
    else if (protocol == QAbstractSocket::IPv6Protocol) protocolStr = QLatin1String("IPv6Protocol");
    else protocolStr = QLatin1String("UnknownNetworkLayerProtocol");
#endif

    resetSocketLayer();
    socketEngine = QAbstractSocketEngine::createSocketEngine(q->socketType(), proxyInUse, q);
    if (!socketEngine) {
        socketError = QAbstractSocket::UnsupportedSocketOperationError;
        q->setErrorString(QAbstractSocket::tr("Operation on socket is not supported"));
        return false;
    }
#ifndef QT_NO_BEARERMANAGEMENT
    //copy network session down to the socket engine (if it has been set)
    socketEngine->setProperty("_q_networksession", q->property("_q_networksession"));
#endif
#ifndef QT_NO_NETWORKPROXY
    //copy user agent to socket engine (if it has been set)
    socketEngine->setProperty("_q_user-agent", q->property("_q_user-agent"));
#endif
    if (!socketEngine->initialize(q->socketType(), protocol)) {
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::initSocketLayer(%s, %s) failed (%s)",
               typeStr.toLatin1().constData(), protocolStr.toLatin1().constData(),
               socketEngine->errorString().toLatin1().constData());
#endif
        socketError = socketEngine->error();
    q->setErrorString(socketEngine->errorString());
        return false;
    }

    if (threadData->eventDispatcher)
        socketEngine->setReceiver(this);

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::initSocketLayer(%s, %s) success",
           typeStr.toLatin1().constData(), protocolStr.toLatin1().constData());
#endif
    return true;
}

bool QAbstractSocketPrivate::canReadNotification()
{
    Q_Q(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::canReadNotification()");
#endif

    // Prevent recursive calls
    if (readSocketNotifierCalled) {
        if (!readSocketNotifierStateSet) {
            readSocketNotifierStateSet = true;
            readSocketNotifierState = socketEngine->isReadNotificationEnabled();
            socketEngine->setReadNotificationEnabled(false);
        }
    }
    QScopedValueRollback<bool> rsncrollback(readSocketNotifierCalled);
    readSocketNotifierCalled = true;

    if (!isBuffered)
        socketEngine->setReadNotificationEnabled(false);

    // If buffered, read data from the socket into the read buffer
    qint64 newBytes = 0;
    if (isBuffered) {
        // Return if there is no space in the buffer
        if (readBufferMaxSize && readBuffer.size() >= readBufferMaxSize) {
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::canReadNotification() buffer is full");
#endif
            return false;
        }

        // If reading from the socket fails after getting a read
        // notification, close the socket.
        newBytes = readBuffer.size();
        if (!readFromSocket()) {
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::canReadNotification() disconnecting socket");
#endif
            q->disconnectFromHost();
            return false;
        }
        newBytes = readBuffer.size() - newBytes;

        // If read buffer is full, disable the read socket notifier.
        if (readBufferMaxSize && readBuffer.size() == readBufferMaxSize) {
            socketEngine->setReadNotificationEnabled(false);
        }
    }

    // only emit readyRead() when not recursing, and only if there is data available
    bool hasData = newBytes > 0
#ifndef QT_NO_UDPSOCKET
        || (!isBuffered && socketType != QAbstractSocket::TcpSocket && socketEngine && socketEngine->hasPendingDatagrams())
#endif
        || (!isBuffered && socketType == QAbstractSocket::TcpSocket && socketEngine)
        ;

    if (!emittedReadyRead && hasData) {
        QScopedValueRollback<bool> r(emittedReadyRead);
        emittedReadyRead = true;
        emit q->readyRead();
    }

    // If we were closed as a result of the readyRead() signal,
    // return.
    if (state == QAbstractSocket::UnconnectedState || state == QAbstractSocket::ClosingState) {
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::canReadNotification() socket is closing - returning");
#endif
        return true;
    }

    if (!hasData && socketEngine)
        socketEngine->setReadNotificationEnabled(true);

    // reset the read socket notifier state if we reentered inside the
    // readyRead() connected slot.
    if (readSocketNotifierStateSet && socketEngine &&
        readSocketNotifierState != socketEngine->isReadNotificationEnabled()) {
        socketEngine->setReadNotificationEnabled(readSocketNotifierState);
        readSocketNotifierStateSet = false;
    }
    return true;
}

bool QAbstractSocketPrivate::canWriteNotification()
{
#if defined (Q_OS_WIN)
    if (socketEngine && socketEngine->isWriteNotificationEnabled())
        socketEngine->setWriteNotificationEnabled(false);
#endif

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::canWriteNotification() flushing");
#endif
    int tmp = writeBuffer.size();
    flush();

    if (socketEngine) {
#if defined (Q_OS_WIN)
        if (!writeBuffer.isEmpty())
            socketEngine->setWriteNotificationEnabled(true);
#else
        if (writeBuffer.isEmpty() && socketEngine->bytesToWrite() == 0)
            socketEngine->setWriteNotificationEnabled(false);
#endif
    }

    return (writeBuffer.size() < tmp);
}

void QAbstractSocketPrivate::connectionNotification()
{
    // If in connecting state, check if the connection has been
    // established, otherwise flush pending data.
    if (state == QAbstractSocket::ConnectingState) {
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::connectionNotification() testing connection");
#endif
        _q_testConnection();
    }
}

bool QAbstractSocketPrivate::flush()
{
    Q_Q(QAbstractSocket);
    if (!socketEngine || !socketEngine->isValid() || (writeBuffer.isEmpty()
        && socketEngine->bytesToWrite() == 0)) {
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::flush() nothing to do: valid ? %s, writeBuffer.isEmpty() ? %s",
           socketEngine->isValid() ? "yes" : "no", writeBuffer.isEmpty() ? "yes" : "no");
#endif

        // this covers the case when the buffer was empty, but we had to wait for the socket engine to finish
        if (state == QAbstractSocket::ClosingState)
            q->disconnectFromHost();

        return false;
    }

    int nextSize = writeBuffer.nextDataBlockSize();
    const char *ptr = writeBuffer.readPointer();

    // Attempt to write it all in one chunk.
    qint64 written = socketEngine->write(ptr, nextSize);
    if (written < 0) {
        socketError = socketEngine->error();
        q->setErrorString(socketEngine->errorString());
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug() << "QAbstractSocketPrivate::flush() write error, aborting." << socketEngine->errorString();
#endif
        emit q->error(socketError);
        // an unexpected error so close the socket.
        q->abort();
        return false;
    }

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::flush() %lld bytes written to the network",
           written);
#endif

    // Remove what we wrote so far.
    writeBuffer.free(written);
    if (written > 0) {
        // Don't emit bytesWritten() recursively.
        if (!emittedBytesWritten) {
            QScopedValueRollback<bool> r(emittedBytesWritten);
            emittedBytesWritten = true;
            emit q->bytesWritten(written);
        }
    }

    if (writeBuffer.isEmpty() && socketEngine && socketEngine->isWriteNotificationEnabled()
        && !socketEngine->bytesToWrite())
        socketEngine->setWriteNotificationEnabled(false);
    if (state == QAbstractSocket::ClosingState)
        q->disconnectFromHost();

    return true;
}

#ifndef QT_NO_NETWORKPROXY

void QAbstractSocketPrivate::resolveProxy(const QString &hostname, quint16 port)
{
    QList<QNetworkProxy> proxies;

    if (proxy.type() != QNetworkProxy::DefaultProxy) {
        // a non-default proxy was set with setProxy
        proxies << proxy;
    } else {
        // try the application settings instead
        QNetworkProxyQuery query(hostname, port, QString(),
                                 socketType == QAbstractSocket::TcpSocket ?
                                 QNetworkProxyQuery::TcpSocket :
                                 QNetworkProxyQuery::UdpSocket);
        proxies = QNetworkProxyFactory::proxyForQuery(query);
    }

    // return the first that we can use
    foreach (const QNetworkProxy &p, proxies) {
        if (socketType == QAbstractSocket::UdpSocket &&
            (p.capabilities() & QNetworkProxy::UdpTunnelingCapability) == 0)
            continue;

        if (socketType == QAbstractSocket::TcpSocket &&
            (p.capabilities() & QNetworkProxy::TunnelingCapability) == 0)
            continue;

        proxyInUse = p;
        return;
    }

    // no proxy found
    // DefaultProxy here will raise an error
    proxyInUse = QNetworkProxy();
}

void QAbstractSocketPrivate::startConnectingByName(const QString &host)
{
    Q_Q(QAbstractSocket);
    if (state == QAbstractSocket::ConnectingState || state == QAbstractSocket::ConnectedState)
        return;

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::startConnectingByName(host == %s)", qPrintable(host));
#endif

    // ### Let the socket engine drive this?
    state = QAbstractSocket::ConnectingState;
    emit q->stateChanged(state);

    connectTimeElapsed = 0;

    if (initSocketLayer(QAbstractSocket::UnknownNetworkLayerProtocol)) {
        if (socketEngine->connectToHostByName(host, port) ||
            socketEngine->state() == QAbstractSocket::ConnectingState) {
            cachedSocketDescriptor = socketEngine->socketDescriptor();

            return;
        }

        // failed to connect
        socketError = socketEngine->error();
        q->setErrorString(socketEngine->errorString());
    }

    state = QAbstractSocket::UnconnectedState;
    emit q->error(socketError);
    emit q->stateChanged(state);
}

#endif

void QAbstractSocketPrivate::_q_startConnecting(const QHostInfo &hostInfo)
{
    Q_Q(QAbstractSocket);
    if (state != QAbstractSocket::HostLookupState)
        return;

    if (hostLookupId != -1 && hostLookupId != hostInfo.lookupId()) {
        qWarning("QAbstractSocketPrivate::_q_startConnecting() received hostInfo for wrong lookup ID %d expected %d", hostInfo.lookupId(), hostLookupId);
    }

    addresses = hostInfo.addresses();

#if defined(QABSTRACTSOCKET_DEBUG)
    QString s = QLatin1String("{");
    for (int i = 0; i < addresses.count(); ++i) {
        if (i != 0) s += QLatin1String(", ");
        s += addresses.at(i).toString();
    }
    s += QLatin1Char('}');
    qDebug("QAbstractSocketPrivate::_q_startConnecting(hostInfo == %s)", s.toLatin1().constData());
#endif

    // Try all addresses twice.
    addresses += addresses;

    // If there are no addresses in the host list, report this to the
    // user.
    if (addresses.isEmpty()) {
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::_q_startConnecting(), host not found");
#endif
        state = QAbstractSocket::UnconnectedState;
        socketError = QAbstractSocket::HostNotFoundError;
        q->setErrorString(QAbstractSocket::tr("Host not found"));
        emit q->stateChanged(state);
        emit q->error(QAbstractSocket::HostNotFoundError);
        return;
    }

    // Enter Connecting state (see also sn_write, which is called by
    // the write socket notifier after connect())
    state = QAbstractSocket::ConnectingState;
    emit q->stateChanged(state);

    // Report the successful host lookup
    emit q->hostFound();

    // Reset the total time spent connecting.
    connectTimeElapsed = 0;

    // The addresses returned by the lookup will be tested one after
    // another by _q_connectToNextAddress().
    _q_connectToNextAddress();
}

void QAbstractSocketPrivate::_q_connectToNextAddress()
{
    Q_Q(QAbstractSocket);
    do {
        // Check for more pending addresses
        if (addresses.isEmpty()) {
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), all addresses failed.");
#endif
            state = QAbstractSocket::UnconnectedState;
            if (socketEngine) {
                if ((socketEngine->error() == QAbstractSocket::UnknownSocketError
#ifdef Q_OS_AIX
                     // On AIX, the second connect call will result in EINVAL and not
                     // ECONNECTIONREFUSED; although the meaning is the same.
                     || socketEngine->error() == QAbstractSocket::UnsupportedSocketOperationError
#endif
                    ) && socketEngine->state() == QAbstractSocket::ConnectingState) {
                    socketError = QAbstractSocket::ConnectionRefusedError;
                    q->setErrorString(QAbstractSocket::tr("Connection refused"));
                } else {
                    socketError = socketEngine->error();
                    q->setErrorString(socketEngine->errorString());
                }
            } else {
//                socketError = QAbstractSocket::ConnectionRefusedError;
//                q->setErrorString(QAbstractSocket::tr("Connection refused"));
            }
            emit q->stateChanged(state);
            emit q->error(socketError);
            return;
        }

        // Pick the first host address candidate
        host = addresses.takeFirst();
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), connecting to %s:%i, %d left to try",
               host.toString().toLatin1().constData(), port, addresses.count());
#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.protocol())) {
            // 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)) {
            //_q_testConnection();
            fetchConnectionParameters();
            return;
        }

        // cache the socket descriptor even if we're not fully connected yet
        cachedSocketDescriptor = socketEngine->socketDescriptor();

        // 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()),
                                 Qt::DirectConnection);
            }
            connectTimer->start(QT_CONNECT_TIMEOUT);
        }

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

void QAbstractSocketPrivate::_q_testConnection()
{
    if (socketEngine) {
        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();
            if (pendingClose) {
                q_func()->disconnectFromHost();
                pendingClose = false;
            }
            return;
        }

        // don't retry the other addresses if we had a proxy error
        if (isProxyError(socketEngine->error()))
            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();
}

void QAbstractSocketPrivate::_q_abortConnectionAttempt()
{
    Q_Q(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocketPrivate::_q_abortConnectionAttempt() (timed out)");
#endif
    if (socketEngine)
        socketEngine->setWriteNotificationEnabled(false);

    connectTimer->stop();

    if (addresses.isEmpty()) {
        state = QAbstractSocket::UnconnectedState;
        socketError = QAbstractSocket::SocketTimeoutError;
        q->setErrorString(QAbstractSocket::tr("Connection timed out"));
        emit q->stateChanged(state);
        emit q->error(socketError);
    } else {
        _q_connectToNextAddress();
    }
}

void QAbstractSocketPrivate::_q_forceDisconnect()
{
    Q_Q(QAbstractSocket);
    if (socketEngine && socketEngine->isValid() && state == QAbstractSocket::ClosingState) {
        socketEngine->close();
        q->disconnectFromHost();
    }
}

bool QAbstractSocketPrivate::readFromSocket()
{
    Q_Q(QAbstractSocket);
    // Find how many bytes we can read from the socket layer.
    qint64 bytesToRead = socketEngine->bytesAvailable();
    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;
}

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
}


void QAbstractSocketPrivate::pauseSocketNotifiers(QAbstractSocket *socket)
{
    QAbstractSocketEngine *socketEngine = socket->d_func()->socketEngine;
    if (!socketEngine)
        return;
    socket->d_func()->prePauseReadSocketNotifierState = socketEngine->isReadNotificationEnabled();
    socket->d_func()->prePauseWriteSocketNotifierState = socketEngine->isWriteNotificationEnabled();
    socket->d_func()->prePauseExceptionSocketNotifierState = socketEngine->isExceptionNotificationEnabled();
    socketEngine->setReadNotificationEnabled(false);
    socketEngine->setWriteNotificationEnabled(false);
    socketEngine->setExceptionNotificationEnabled(false);
}

void QAbstractSocketPrivate::resumeSocketNotifiers(QAbstractSocket *socket)
{
    QAbstractSocketEngine *socketEngine = socket->d_func()->socketEngine;
    if (!socketEngine)
        return;
    socketEngine->setReadNotificationEnabled(socket->d_func()->prePauseReadSocketNotifierState);
    socketEngine->setWriteNotificationEnabled(socket->d_func()->prePauseWriteSocketNotifierState);
    socketEngine->setExceptionNotificationEnabled(socket->d_func()->prePauseExceptionSocketNotifierState);
}

QAbstractSocketEngine* QAbstractSocketPrivate::getSocketEngine(QAbstractSocket *socket)
{
    return socket->d_func()->socketEngine;
}


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;
}

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;
}

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

bool QAbstractSocket::isValid() const
{
    return d_func()->socketEngine ? d_func()->socketEngine->isValid() : isOpen();
}

void QAbstractSocket::connectToHost(const QString &hostName, quint16 port,
                                    OpenMode openMode)
{
    QMetaObject::invokeMethod(this, "connectToHostImplementation",
                              Qt::DirectConnection,
                              Q_ARG(QString, hostName),
                              Q_ARG(quint16, port),
                              Q_ARG(OpenMode, openMode));
}

void QAbstractSocket::connectToHostImplementation(const QString &hostName, quint16 port,
                                                  OpenMode openMode)
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::connectToHost(\"%s\", %i, %i)...", qPrintable(hostName), port,
           (int) openMode);
#endif

    if (d->state == ConnectedState || d->state == ConnectingState
        || d->state == ClosingState || d->state == HostLookupState) {
        qWarning("QAbstractSocket::connectToHost() called when already looking up or connecting/connected to \"%s\"", qPrintable(hostName));
        return;
    }

    d->hostName = hostName;
    d->port = port;
    d->state = UnconnectedState;
    d->readBuffer.clear();
    d->writeBuffer.clear();
    d->abortCalled = false;
    d->closeCalled = false;
    d->pendingClose = false;
    d->localPort = 0;
    d->peerPort = 0;
    d->localAddress.clear();
    d->peerAddress.clear();
    d->peerName = hostName;
    if (d->hostLookupId != -1) {
        QHostInfo::abortHostLookup(d->hostLookupId);
        d->hostLookupId = -1;
    }

#ifndef QT_NO_NETWORKPROXY
    // Get the proxy information
    d->resolveProxy(hostName, port);
    if (d->proxyInUse.type() == QNetworkProxy::DefaultProxy) {
        // failed to setup the proxy
        d->socketError = QAbstractSocket::UnsupportedSocketOperationError;
        setErrorString(QAbstractSocket::tr("Operation on socket is not supported"));
        emit error(d->socketError);
        return;
    }
#endif

    if (openMode & QIODevice::Unbuffered)
        d->isBuffered = false; // Unbuffered QTcpSocket
    else if (!d_func()->isBuffered)
        openMode |= QAbstractSocket::Unbuffered; // QUdpSocket

    QIODevice::open(openMode);
    d->state = HostLookupState;
    emit stateChanged(d->state);

    QHostAddress temp;
    if (temp.setAddress(hostName)) {
        QHostInfo info;
        info.setAddresses(QList<QHostAddress>() << temp);
        d->_q_startConnecting(info);
#ifndef QT_NO_NETWORKPROXY
    } else if (d->proxyInUse.capabilities() & QNetworkProxy::HostNameLookupCapability) {
        // the proxy supports connection by name, so use it
        d->startConnectingByName(hostName);
        return;
#endif
    } else {
        if (d->threadData->eventDispatcher) {
            // this internal API for QHostInfo either immediately gives us the desired
            // QHostInfo from cache or later calls the _q_startConnecting slot.
            bool immediateResultValid = false;
            QHostInfo hostInfo = qt_qhostinfo_lookup(hostName,
                                                     this,
                                                     SLOT(_q_startConnecting(QHostInfo)),
                                                     &immediateResultValid,
                                                     &d->hostLookupId);
            if (immediateResultValid) {
                d->hostLookupId = -1;
                d->_q_startConnecting(hostInfo);
            }
        }
    }

#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
}

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);
}

qint64 QAbstractSocket::bytesToWrite() const
{
    Q_D(const QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::bytesToWrite() == %i", d->writeBuffer.size());
#endif
    return (qint64)d->writeBuffer.size();
}

qint64 QAbstractSocket::bytesAvailable() const
{
    Q_D(const QAbstractSocket);
    qint64 available = QIODevice::bytesAvailable();

    available += (qint64) d->readBuffer.size();

    if (!d->isBuffered && d->socketEngine && d->socketEngine->isValid())
        available += d->socketEngine->bytesAvailable();

#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::bytesAvailable() == %llu", available);
#endif
    return available;
}

quint16 QAbstractSocket::localPort() const
{
    Q_D(const QAbstractSocket);
    return d->localPort;
}

QHostAddress QAbstractSocket::localAddress() const
{
    Q_D(const QAbstractSocket);
    return d->localAddress;
}

quint16 QAbstractSocket::peerPort() const
{
    Q_D(const QAbstractSocket);
    return d->peerPort;
}

QHostAddress QAbstractSocket::peerAddress() const
{
    Q_D(const QAbstractSocket);
    return d->peerAddress;
}

QString QAbstractSocket::peerName() const
{
    Q_D(const QAbstractSocket);
    return d->peerName.isEmpty() ? d->hostName : d->peerName;
}

bool QAbstractSocket::canReadLine() const
{
    bool hasLine = d_func()->readBuffer.canReadLine();
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::canReadLine() == %s, buffer size = %d, size = %d", hasLine ? "true" : "false",
           d_func()->readBuffer.size(), d_func()->buffer.size());
#endif
    return hasLine || QIODevice::canReadLine();
}

int QAbstractSocket::socketDescriptor() const
{
    Q_D(const QAbstractSocket);
    return d->cachedSocketDescriptor;
}

bool QAbstractSocket::setSocketDescriptor(int socketDescriptor, SocketState socketState,
                                          OpenMode openMode)
{
    Q_D(QAbstractSocket);
#ifndef QT_NO_OPENSSL
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this))
        return socket->setSocketDescriptor(socketDescriptor, socketState, openMode);
#endif

    d->resetSocketLayer();
    d->socketEngine = QAbstractSocketEngine::createSocketEngine(socketDescriptor, this);
    if (!d->socketEngine) {
        d->socketError = UnsupportedSocketOperationError;
        setErrorString(tr("Operation on socket is not supported"));
        return false;
    }
#ifndef QT_NO_BEARERMANAGEMENT
    //copy network session down to the socket engine (if it has been set)
    d->socketEngine->setProperty("_q_networksession", property("_q_networksession"));
#endif
    bool result = d->socketEngine->initialize(socketDescriptor, socketState);
    if (!result) {
        d->socketError = d->socketEngine->error();
        setErrorString(d->socketEngine->errorString());
        return false;
    }

    if (d->threadData->eventDispatcher)
        d->socketEngine->setReceiver(d);

    QIODevice::open(openMode);

    if (d->state != socketState) {
        d->state = socketState;
        emit stateChanged(d->state);
    }

    d->pendingClose = false;
    d->socketEngine->setReadNotificationEnabled(true);
    d->localPort = d->socketEngine->localPort();
    d->peerPort = d->socketEngine->peerPort();
    d->localAddress = d->socketEngine->localAddress();
    d->peerAddress = d->socketEngine->peerAddress();
    d->cachedSocketDescriptor = socketDescriptor;

    return true;
}

void QAbstractSocket::setSocketOption(QAbstractSocket::SocketOption option, const QVariant &value)
{
#ifndef QT_NO_OPENSSL
    if (QSslSocket *sslSocket = qobject_cast<QSslSocket*>(this)) {
        sslSocket->setSocketOption(option, value);
        return;
    }
#endif

    if (!d_func()->socketEngine)
        return;

    switch (option) {
        case LowDelayOption:
            d_func()->socketEngine->setOption(QAbstractSocketEngine::LowDelayOption, value.toInt());
            break;

        case KeepAliveOption:
            d_func()->socketEngine->setOption(QAbstractSocketEngine::KeepAliveOption, value.toInt());
            break;

        case MulticastTtlOption:
                d_func()->socketEngine->setOption(QAbstractSocketEngine::MulticastTtlOption, value.toInt());
                break;

        case MulticastLoopbackOption:
                d_func()->socketEngine->setOption(QAbstractSocketEngine::MulticastLoopbackOption, value.toInt());
                break;
    }
}

QVariant QAbstractSocket::socketOption(QAbstractSocket::SocketOption option)
{
#ifndef QT_NO_OPENSSL
    if (QSslSocket *sslSocket = qobject_cast<QSslSocket*>(this)) {
        return sslSocket->socketOption(option);
    }
#endif

    if (!d_func()->socketEngine)
        return QVariant();

    int ret = -1;
    switch (option) {
        case LowDelayOption:
            ret = d_func()->socketEngine->option(QAbstractSocketEngine::LowDelayOption);
            break;

        case KeepAliveOption:
            ret = d_func()->socketEngine->option(QAbstractSocketEngine::KeepAliveOption);
            break;

        case MulticastTtlOption:
                ret = d_func()->socketEngine->option(QAbstractSocketEngine::MulticastTtlOption);
                break;
        case MulticastLoopbackOption:
                ret = d_func()->socketEngine->option(QAbstractSocketEngine::MulticastLoopbackOption);
                break;
    }
    if (ret == -1)
        return QVariant();
    else
        return QVariant(ret);
}


/*
   Returns the difference between msecs and elapsed. If msecs is -1,
   however, -1 is returned.
*/
static int qt_timeout_value(int msecs, int elapsed)
{
    if (msecs == -1)
        return -1;

    int timeout = msecs - elapsed;
    return timeout < 0 ? 0 : timeout;
}

bool QAbstractSocket::waitForConnected(int msecs)
{
    Q_D(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::waitForConnected(%i)", msecs);
#endif

    if (state() == ConnectedState) {
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::waitForConnected(%i) already connected", msecs);
#endif
        return true;
    }

#ifndef QT_NO_OPENSSL
    // Manual polymorphism; this function is not virtual, but has an overload
    // in QSslSocket.
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this))
        return socket->waitForConnected(msecs);
#endif

    bool wasPendingClose = d->pendingClose;
    d->pendingClose = false;
    QElapsedTimer stopWatch;
    stopWatch.start();

    if (d->state == HostLookupState) {
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::waitForConnected(%i) doing host name lookup", msecs);
#endif
        QHostInfo::abortHostLookup(d->hostLookupId);
        d->hostLookupId = -1;
#ifndef QT_NO_BEARERMANAGEMENT
        QSharedPointer<QNetworkSession> networkSession;
        QVariant v(property("_q_networksession"));
        if (v.isValid()) {
            networkSession = qvariant_cast< QSharedPointer<QNetworkSession> >(v);
            d->_q_startConnecting(QHostInfoPrivate::fromName(d->hostName, networkSession));
        } else
#endif
        d->_q_startConnecting(QHostInfo::fromName(d->hostName));
    }
    if (state() == UnconnectedState)
        return false; // connect not im progress anymore!

    bool timedOut = true;
#if defined (QABSTRACTSOCKET_DEBUG)
    int attempt = 1;
#endif
    while (state() == ConnectingState && (msecs == -1 || stopWatch.elapsed() < msecs)) {
        int timeout = qt_timeout_value(msecs, stopWatch.elapsed());
        if (msecs != -1 && timeout > QT_CONNECT_TIMEOUT)
            timeout = QT_CONNECT_TIMEOUT;
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::waitForConnected(%i) waiting %.2f secs for connection attempt #%i",
               msecs, timeout / 1000.0, attempt++);
#endif
        timedOut = false;

        if (d->socketEngine && d->socketEngine->waitForWrite(timeout, &timedOut) && !timedOut) {
            d->_q_testConnection();
        } else {
            d->_q_connectToNextAddress();
        }
    }

    if ((timedOut && state() != ConnectedState) || state() == ConnectingState) {
        d->socketError = SocketTimeoutError;
        d->state = UnconnectedState;
        emit stateChanged(d->state);
        d->resetSocketLayer();
        setErrorString(tr("Socket operation timed out"));
    }

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::waitForConnected(%i) == %s", msecs,
           state() == ConnectedState ? "true" : "false");
#endif
    if (state() != ConnectedState)
        return false;
    if (wasPendingClose)
        disconnectFromHost();
    return true;
}

bool QAbstractSocket::waitForReadyRead(int msecs)
{
    Q_D(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::waitForReadyRead(%i)", msecs);
#endif

    // require calling connectToHost() before waitForReadyRead()
    if (state() == UnconnectedState) {
        /* If all you have is a QIODevice pointer to an abstractsocket, you cannot check
           this, so you cannot avoid this warning. */
//        qWarning("QAbstractSocket::waitForReadyRead() is not allowed in UnconnectedState");
        return false;
    }

    QElapsedTimer stopWatch;
    stopWatch.start();

    // handle a socket in connecting state
    if (state() == HostLookupState || state() == ConnectingState) {
        if (!waitForConnected(msecs))
            return false;
    }

    Q_ASSERT(d->socketEngine);
    do {
        bool readyToRead = false;
        bool readyToWrite = false;
        if (!d->socketEngine->waitForReadOrWrite(&readyToRead, &readyToWrite, true, !d->writeBuffer.isEmpty(),
                                               qt_timeout_value(msecs, stopWatch.elapsed()))) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::waitForReadyRead(%i) failed (%i, %s)",
                   msecs, d->socketError, errorString().toLatin1().constData());
#endif
            emit error(d->socketError);
            if (d->socketError != SocketTimeoutError)
                close();
            return false;
        }

        if (readyToRead) {
            if (d->canReadNotification())
                return true;
        }

        if (readyToWrite)
            d->canWriteNotification();

        if (state() != ConnectedState)
            return false;
    } while (msecs == -1 || qt_timeout_value(msecs, stopWatch.elapsed()) > 0);
    return false;
}

bool QAbstractSocket::waitForBytesWritten(int msecs)
{
    Q_D(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::waitForBytesWritten(%i)", msecs);
#endif

    // require calling connectToHost() before waitForBytesWritten()
    if (state() == UnconnectedState) {
        qWarning("QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState");
        return false;
    }

    if (d->writeBuffer.isEmpty())
        return false;

    QElapsedTimer stopWatch;
    stopWatch.start();

    // handle a socket in connecting state
    if (state() == HostLookupState || state() == ConnectingState) {
        if (!waitForConnected(msecs))
            return false;
    }

    forever {
        bool readyToRead = false;
        bool readyToWrite = false;
        if (!d->socketEngine->waitForReadOrWrite(&readyToRead, &readyToWrite, true, !d->writeBuffer.isEmpty(),
                                               qt_timeout_value(msecs, stopWatch.elapsed()))) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::waitForBytesWritten(%i) failed (%i, %s)",
                   msecs, d->socketError, errorString().toLatin1().constData());
#endif
            emit error(d->socketError);
            if (d->socketError != SocketTimeoutError)
                close();
            return false;
        }

        if (readyToRead) {
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::waitForBytesWritten calls canReadNotification");
#endif
            if(!d->canReadNotification())
                return false;
        }


        if (readyToWrite) {
            if (d->canWriteNotification()) {
#if defined (QABSTRACTSOCKET_DEBUG)
                qDebug("QAbstractSocket::waitForBytesWritten returns true");
#endif
                return true;
            }
        }

        if (state() != ConnectedState)
            return false;
    }
    return false;
}

bool QAbstractSocket::waitForDisconnected(int msecs)
{
    Q_D(QAbstractSocket);
#ifndef QT_NO_OPENSSL
    // Manual polymorphism; this function is not virtual, but has an overload
    // in QSslSocket.
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this))
        return socket->waitForDisconnected(msecs);
#endif

    // require calling connectToHost() before waitForDisconnected()
    if (state() == UnconnectedState) {
        qWarning("QAbstractSocket::waitForDisconnected() is not allowed in UnconnectedState");
        return false;
    }

    QElapsedTimer stopWatch;
    stopWatch.start();

    // handle a socket in connecting state
    if (state() == HostLookupState || state() == ConnectingState) {
        if (!waitForConnected(msecs))
            return false;
        if (state() == UnconnectedState)
            return true;
    }

    forever {
        bool readyToRead = false;
        bool readyToWrite = false;
        if (!d->socketEngine->waitForReadOrWrite(&readyToRead, &readyToWrite, state() == ConnectedState,
                                               !d->writeBuffer.isEmpty(),
                                               qt_timeout_value(msecs, stopWatch.elapsed()))) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
#if defined (QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::waitForReadyRead(%i) failed (%i, %s)",
                   msecs, d->socketError, errorString().toLatin1().constData());
#endif
            emit error(d->socketError);
            if (d->socketError != SocketTimeoutError)
                close();
            return false;
        }

        if (readyToRead)
            d->canReadNotification();
        if (readyToWrite)
            d->canWriteNotification();

        if (state() == UnconnectedState)
            return true;
    }
    return false;
}

void QAbstractSocket::abort()
{
    Q_D(QAbstractSocket);
#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::abort()");
#endif
    if (d->state == UnconnectedState)
        return;
#ifndef QT_NO_OPENSSL
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this)) {
        socket->abort();
        return;
    }
#endif
    if (d->connectTimer) {
        d->connectTimer->stop();
        delete d->connectTimer;
        d->connectTimer = 0;
    }

    d->writeBuffer.clear();
    d->abortCalled = true;
    close();
}

bool QAbstractSocket::isSequential() const
{
    return true;
}

bool QAbstractSocket::atEnd() const
{
    return QIODevice::atEnd() && (!isOpen() || d_func()->readBuffer.isEmpty());
}

// Note! docs copied to QSslSocket::flush()
bool QAbstractSocket::flush()
{
    Q_D(QAbstractSocket);
#ifndef QT_NO_OPENSSL
    // Manual polymorphism; flush() isn't virtual, but QSslSocket overloads
    // it.
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this))
        return socket->flush();
#endif
    Q_CHECK_SOCKETENGINE(false);
    return d->flush();
}

qint64 QAbstractSocket::readData(char *data, qint64 maxSize)
{
    Q_D(QAbstractSocket);

    // This is for a buffered QTcpSocket
    if (d->isBuffered && d->readBuffer.isEmpty())
        // if we're still connected, return 0 indicating there may be more data in the future
        // if we're not connected, return -1 indicating EOF
        return d->state == QAbstractSocket::ConnectedState ? qint64(0) : qint64(-1);

    // short cut for a char read if we have something in the buffer
    if (maxSize == 1 && !d->readBuffer.isEmpty()) {
        *data = d->readBuffer.getChar();
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::readData(%p '%c (0x%.2x)', 1) == 1 [char buffer]",
               data, isprint(int(uchar(*data))) ? *data : '?', *data);
#endif
        if (d->readBuffer.isEmpty() && d->socketEngine && d->socketEngine->isValid())
            d->socketEngine->setReadNotificationEnabled(true);
        return 1;
    }

    // Special case for an Unbuffered QTcpSocket
    // Re-filling the buffer.
    if (d->socketType == TcpSocket
            && !d->isBuffered
            && d->readBuffer.size() < maxSize
            && d->readBufferMaxSize > 0
            && maxSize < d->readBufferMaxSize
            && d->socketEngine
            && d->socketEngine->isValid()) {
        // Our buffer is empty and a read() was requested for a byte amount that is smaller
        // than the readBufferMaxSize. This means that we should fill our buffer since we want
        // such small reads come from the buffer and not always go to the costly socket engine read()
        qint64 bytesToRead = d->socketEngine->bytesAvailable();
        if (bytesToRead > 0) {
            char *ptr = d->readBuffer.reserve(bytesToRead);
            qint64 readBytes = d->socketEngine->read(ptr, bytesToRead);
            if (readBytes == -2) {
                // No bytes currently available for reading.
                d->readBuffer.chop(bytesToRead);
            } else {
                d->readBuffer.chop(int(bytesToRead - (readBytes < 0 ? qint64(0) : readBytes)));
            }
        }
   }

    // First try to satisfy the read from the buffer
    qint64 bytesToRead = qMin(qint64(d->readBuffer.size()), maxSize);
    qint64 readSoFar = 0;
    while (readSoFar < bytesToRead) {
        const char *ptr = d->readBuffer.readPointer();
        int bytesToReadFromThisBlock = qMin(int(bytesToRead - readSoFar),
                                            d->readBuffer.nextDataBlockSize());
        memcpy(data + readSoFar, ptr, bytesToReadFromThisBlock);
        readSoFar += bytesToReadFromThisBlock;
        d->readBuffer.free(bytesToReadFromThisBlock);
    }

    if (d->socketEngine && !d->socketEngine->isReadNotificationEnabled() && d->socketEngine->isValid())
        d->socketEngine->setReadNotificationEnabled(true);

    if (readSoFar > 0) {
        // we read some data from buffer.
        // Just return, readyRead will be emitted again
#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::readData(%p '%c (0x%.2x)', %lli) == %lli [buffer]",
               data, isprint(int(uchar(*data))) ? *data : '?', *data, maxSize, readSoFar);
#endif

        if (d->readBuffer.isEmpty() && d->socketEngine)
            d->socketEngine->setReadNotificationEnabled(true);
        return readSoFar;
    }

    // This code path is for Unbuffered QTcpSocket or for connected UDP

    if (!d->isBuffered) {
        if (!d->socketEngine)
            return -1;          // no socket engine is probably EOF
        if (!d->socketEngine->isValid())
            return -1; // This is for unbuffered TCP when we already had been disconnected
        if (d->state != QAbstractSocket::ConnectedState)
            return -1; // This is for unbuffered TCP if we're not connected yet
        qint64 readBytes = d->socketEngine->read(data, maxSize);
        if (readBytes == -2) {
            // -2 from the engine means no bytes available (EAGAIN) so read more later
            return 0;
        } else if (readBytes < 0) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
            d->resetSocketLayer();
            d->state = QAbstractSocket::UnconnectedState;
        } else if (!d->socketEngine->isReadNotificationEnabled()) {
            // Only do this when there was no error
            d->socketEngine->setReadNotificationEnabled(true);
        }

#if defined (QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::readData(%p \"%s\", %lli) == %lld [engine]",
               data, qt_prettyDebug(data, 32, readBytes).data(), maxSize,
               readBytes);
#endif
        return readBytes;
    }


#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::readData(%p \"%s\", %lli) == %lld [unreachable]",
           data, qt_prettyDebug(data, qMin<qint64>(32, readSoFar), readSoFar).data(),
           maxSize, readSoFar);
#endif
    return readSoFar;
}

qint64 QAbstractSocket::readLineData(char *data, qint64 maxlen)
{
    return QIODevice::readLineData(data, maxlen);
}

qint64 QAbstractSocket::writeData(const char *data, qint64 size)
{
    Q_D(QAbstractSocket);
    if (d->state == QAbstractSocket::UnconnectedState) {
        d->socketError = QAbstractSocket::UnknownSocketError;
        setErrorString(tr("Socket is not connected"));
        return -1;
    }

    if (!d->isBuffered && d->socketType == TcpSocket && d->writeBuffer.isEmpty()) {
        // This code is for the new Unbuffered QTcpSocket use case
        qint64 written = d->socketEngine->write(data, size);
        if (written < 0) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
            return written;
        } else if (written < size) {
            // Buffer what was not written yet
            char *ptr = d->writeBuffer.reserve(size - written);
            memcpy(ptr, data + written, size - written);
            if (d->socketEngine)
                d->socketEngine->setWriteNotificationEnabled(true);
        }
        return size; // size=actually written + what has been buffered
    } else if (!d->isBuffered && d->socketType != TcpSocket) {
        // This is for a QUdpSocket that was connect()ed
        qint64 written = d->socketEngine->write(data, size);
        if (written < 0) {
            d->socketError = d->socketEngine->error();
            setErrorString(d->socketEngine->errorString());
        } else if (!d->writeBuffer.isEmpty()) {
            d->socketEngine->setWriteNotificationEnabled(true);
        }

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::writeData(%p \"%s\", %lli) == %lli", data,
           qt_prettyDebug(data, qMin((int)size, 32), size).data(),
           size, written);
#endif
        if (written >= 0)
            emit bytesWritten(written);
        return written;
    }

    // This is the code path for normal buffered QTcpSocket or
    // unbuffered QTcpSocket when there was already something in the
    // write buffer and therefore we could not do a direct engine write.
    // We just write to our write buffer and enable the write notifier
    // The write notifier then flush()es the buffer.

    char *ptr = d->writeBuffer.reserve(size);
    if (size == 1)
        *ptr = *data;
    else
        memcpy(ptr, data, size);

    qint64 written = size;

    if (d->socketEngine && !d->writeBuffer.isEmpty())
        d->socketEngine->setWriteNotificationEnabled(true);

#if defined (QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::writeData(%p \"%s\", %lli) == %lli", data,
           qt_prettyDebug(data, qMin((int)size, 32), size).data(),
           size, written);
#endif
    return written;
}

void QAbstractSocket::setLocalPort(quint16 port)
{
    Q_D(QAbstractSocket);
    d->localPort = port;
}

void QAbstractSocket::setLocalAddress(const QHostAddress &address)
{
    Q_D(QAbstractSocket);
    d->localAddress = address;
}

void QAbstractSocket::setPeerPort(quint16 port)
{
    Q_D(QAbstractSocket);
    d->peerPort = port;
}

void QAbstractSocket::setPeerAddress(const QHostAddress &address)
{
    Q_D(QAbstractSocket);
    d->peerAddress = address;
}

void QAbstractSocket::setPeerName(const QString &name)
{
    Q_D(QAbstractSocket);
    d->peerName = name;
}

void QAbstractSocket::close()
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::close()");
#endif
    QIODevice::close();
    if (d->state != UnconnectedState) {
        d->closeCalled = true;
        disconnectFromHost();
    }

    d->localPort = 0;
    d->peerPort = 0;
    d->localAddress.clear();
    d->peerAddress.clear();
    d->peerName.clear();
    d->cachedSocketDescriptor = -1;
}

void QAbstractSocket::disconnectFromHost()
{
    QMetaObject::invokeMethod(this, "disconnectFromHostImplementation",
                              Qt::DirectConnection);
}

void QAbstractSocket::disconnectFromHostImplementation()
{
    Q_D(QAbstractSocket);
#if defined(QABSTRACTSOCKET_DEBUG)
    qDebug("QAbstractSocket::disconnectFromHost()");
#endif

    if (d->state == UnconnectedState) {
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::disconnectFromHost() was called on an unconnected socket");
#endif
        return;
    }

    if (!d->abortCalled && (d->state == ConnectingState || d->state == HostLookupState)) {
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::disconnectFromHost() but we're still connecting");
#endif
        d->pendingClose = true;
        return;
    }

#ifdef QT3_SUPPORT
    emit connectionClosed(); // compat signal
#endif

    // Disable and delete read notification
    if (d->socketEngine)
        d->socketEngine->setReadNotificationEnabled(false);

    if (d->abortCalled) {
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::disconnectFromHost() aborting immediately");
#endif
        if (d->state == HostLookupState) {
            QHostInfo::abortHostLookup(d->hostLookupId);
            d->hostLookupId = -1;
        }
    } else {
        // Perhaps emit closing()
        if (d->state != ClosingState) {
            d->state = ClosingState;
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::disconnectFromHost() emits stateChanged()(ClosingState)");
#endif
            emit stateChanged(d->state);
        } else {
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::disconnectFromHost() return from delayed close");
#endif
        }

        // Wait for pending data to be written.
        if (d->socketEngine && d->socketEngine->isValid() && (d->writeBuffer.size() > 0
            || d->socketEngine->bytesToWrite() > 0)) {
            // hack: when we are waiting for the socket engine to write bytes (only
            // possible when using Socks5 or HTTP socket engine), then close
            // anyway after 2 seconds. This is to prevent a timeout on Mac, where we
            // sometimes just did not get the write notifier from the underlying
            // CFSocket and no progress was made.
            if (d->writeBuffer.size() == 0 && d->socketEngine->bytesToWrite() > 0) {
                if (!d->disconnectTimer) {
                    d->disconnectTimer = new QTimer(this);
                    connect(d->disconnectTimer, SIGNAL(timeout()), this,
                            SLOT(_q_forceDisconnect()), Qt::DirectConnection);
                }
                if (!d->disconnectTimer->isActive())
                    d->disconnectTimer->start(2000);
            }
            d->socketEngine->setWriteNotificationEnabled(true);

#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::disconnectFromHost() delaying disconnect");
#endif
            return;
        } else {
#if defined(QABSTRACTSOCKET_DEBUG)
            qDebug("QAbstractSocket::disconnectFromHost() disconnecting immediately");
#endif
        }
    }

    SocketState previousState = d->state;
    d->resetSocketLayer();
    d->state = UnconnectedState;
    emit stateChanged(d->state);
    emit readChannelFinished();       // we got an EOF

#ifdef QT3_SUPPORT
    emit delayedCloseFinished(); // compat signal
#endif
    // only emit disconnected if we were connected before
    if (previousState == ConnectedState || previousState == ClosingState)
        emit disconnected();

    d->localPort = 0;
    d->peerPort = 0;
    d->localAddress.clear();
    d->peerAddress.clear();

#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::disconnectFromHost() disconnected!");
#endif

    if (d->closeCalled) {
#if defined(QABSTRACTSOCKET_DEBUG)
        qDebug("QAbstractSocket::disconnectFromHost() closed!");
#endif
        d->readBuffer.clear();
        d->writeBuffer.clear();
        QIODevice::close();
    }
}

qint64 QAbstractSocket::readBufferSize() const
{
    return d_func()->readBufferMaxSize;
}

void QAbstractSocket::setReadBufferSize(qint64 size)
{
    Q_D(QAbstractSocket);

#ifndef QT_NO_OPENSSL
    // Manual polymorphism; setReadBufferSize() isn't virtual, but QSslSocket overloads
    // it.
    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this)) {
        socket->setReadBufferSize(size);
        return;
    }
#endif

    if (d->readBufferMaxSize == size)
        return;
    d->readBufferMaxSize = size;
    if (!d->readSocketNotifierCalled && d->socketEngine) {
        // ensure that the read notification is enabled if we've now got
        // room in the read buffer
        // but only if we're not inside canReadNotification -- that will take care on its own
        if ((size == 0 || d->readBuffer.size() < size) && d->state == QAbstractSocket::ConnectedState) // Do not change the notifier unless we are connected.
            d->socketEngine->setReadNotificationEnabled(true);
    }
}

QAbstractSocket::SocketState QAbstractSocket::state() const
{
    return d_func()->state;
}

void QAbstractSocket::setSocketState(SocketState state)
{
    d_func()->state = state;
}

QAbstractSocket::SocketType QAbstractSocket::socketType() const
{
    return d_func()->socketType;
}

QAbstractSocket::SocketError QAbstractSocket::error() const
{
    return d_func()->socketError;
}

void QAbstractSocket::setSocketError(SocketError socketError)
{
    d_func()->socketError = socketError;
}

#ifndef QT_NO_NETWORKPROXY

void QAbstractSocket::setProxy(const QNetworkProxy &networkProxy)
{
    Q_D(QAbstractSocket);
    d->proxy = networkProxy;
}

QNetworkProxy QAbstractSocket::proxy() const
{
    Q_D(const QAbstractSocket);
    return d->proxy;
}
#endif // QT_NO_NETWORKPROXY

#ifdef QT3_SUPPORT

#endif // QT3_SUPPORT

#ifndef QT_NO_DEBUG_STREAM
Q_NETWORK_EXPORT QDebug operator<<(QDebug debug, QAbstractSocket::SocketError error)
{
    switch (error) {
    case QAbstractSocket::ConnectionRefusedError:
        debug << "QAbstractSocket::ConnectionRefusedError";
        break;
    case QAbstractSocket::RemoteHostClosedError:
        debug << "QAbstractSocket::RemoteHostClosedError";
        break;
    case QAbstractSocket::HostNotFoundError:
        debug << "QAbstractSocket::HostNotFoundError";
        break;
    case QAbstractSocket::SocketAccessError:
        debug << "QAbstractSocket::SocketAccessError";
        break;
    case QAbstractSocket::SocketResourceError:
        debug << "QAbstractSocket::SocketResourceError";
        break;
    case QAbstractSocket::SocketTimeoutError:
        debug << "QAbstractSocket::SocketTimeoutError";
        break;
    case QAbstractSocket::DatagramTooLargeError:
        debug << "QAbstractSocket::DatagramTooLargeError";
        break;
    case QAbstractSocket::NetworkError:
        debug << "QAbstractSocket::NetworkError";
        break;
    case QAbstractSocket::AddressInUseError:
        debug << "QAbstractSocket::AddressInUseError";
        break;
    case QAbstractSocket::SocketAddressNotAvailableError:
        debug << "QAbstractSocket::SocketAddressNotAvailableError";
        break;
    case QAbstractSocket::UnsupportedSocketOperationError:
        debug << "QAbstractSocket::UnsupportedSocketOperationError";
        break;
    case QAbstractSocket::UnfinishedSocketOperationError:
        debug << "QAbstractSocket::UnfinishedSocketOperationError";
        break;
    case QAbstractSocket::ProxyAuthenticationRequiredError:
        debug << "QAbstractSocket::ProxyAuthenticationRequiredError";
        break;
    case QAbstractSocket::UnknownSocketError:
        debug << "QAbstractSocket::UnknownSocketError";
        break;
    case QAbstractSocket::ProxyConnectionRefusedError:
        debug << "QAbstractSocket::ProxyConnectionRefusedError";
        break;
    case QAbstractSocket::ProxyConnectionClosedError:
        debug << "QAbstractSocket::ProxyConnectionClosedError";
        break;
    case QAbstractSocket::ProxyConnectionTimeoutError:
        debug << "QAbstractSocket::ProxyConnectionTimeoutError";
        break;
    case QAbstractSocket::ProxyNotFoundError:
        debug << "QAbstractSocket::ProxyNotFoundError";
        break;
    case QAbstractSocket::ProxyProtocolError:
        debug << "QAbstractSocket::ProxyProtocolError";
        break;
    default:
        debug << "QAbstractSocket::SocketError(" << int(error) << ')';
        break;
    }
    return debug;
}

Q_NETWORK_EXPORT QDebug operator<<(QDebug debug, QAbstractSocket::SocketState state)
{
    switch (state) {
    case QAbstractSocket::UnconnectedState:
        debug << "QAbstractSocket::UnconnectedState";
        break;
    case QAbstractSocket::HostLookupState:
        debug << "QAbstractSocket::HostLookupState";
        break;
    case QAbstractSocket::ConnectingState:
        debug << "QAbstractSocket::ConnectingState";
        break;
    case QAbstractSocket::ConnectedState:
        debug << "QAbstractSocket::ConnectedState";
        break;
    case QAbstractSocket::BoundState:
        debug << "QAbstractSocket::BoundState";
        break;
    case QAbstractSocket::ListeningState:
        debug << "QAbstractSocket::ListeningState";
        break;
    case QAbstractSocket::ClosingState:
        debug << "QAbstractSocket::ClosingState";
        break;
    default:
        debug << "QAbstractSocket::SocketState(" << int(state) << ')';
        break;
    }
    return debug;
}
#endif

QT_END_NAMESPACE

#include "moc_qabstractsocket.cpp"