Long live Qt 4.5!

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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtNetwork module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//#define QABSTRACTSOCKET_DEBUG
+
+/*!
+    \class QAbstractSocket
+
+    \brief The QAbstractSocket class provides the base functionality
+    common to all socket types.
+
+    \reentrant
+    \ingroup io
+    \inmodule QtNetwork
+
+    QAbstractSocket is the base class for QTcpSocket and QUdpSocket
+    and contains all common functionality of these two classes. If
+    you need a socket, you have two options:
+
+    \list
+    \i  Instantiate QTcpSocket or QUdpSocket.
+    \i  Create a native socket descriptor, instantiate
+        QAbstractSocket, and call setSocketDescriptor() to wrap the
+        native socket.
+    \endlist
+
+    TCP (Transmission Control Protocol) is a reliable,
+    stream-oriented, connection-oriented transport protocol. UDP
+    (User Datagram Protocol) is an unreliable, datagram-oriented,
+    connectionless protocol. In practice, this means that TCP is
+    better suited for continuous transmission of data, whereas the
+    more lightweight UDP can be used when reliability isn't
+    important.
+
+    QAbstractSocket's API unifies most of the differences between the
+    two protocols. For example, although UDP is connectionless,
+    connectToHost() establishes a virtual connection for UDP sockets,
+    enabling you to use QAbstractSocket in more or less the same way
+    regardless of the underlying protocol. Internally,
+    QAbstractSocket remembers the address and port passed to
+    connectToHost(), and functions like read() and write() use these
+    values.
+
+    At any time, QAbstractSocket has a state (returned by
+    state()). The initial state is UnconnectedState. After
+    calling connectToHost(), the socket first enters
+    HostLookupState. If the host is found, QAbstractSocket enters
+    ConnectingState and emits the hostFound() signal. When the
+    connection has been established, it enters ConnectedState and
+    emits connected(). If an error occurs at any stage, error() is
+    emitted. Whenever the state changes, stateChanged() is emitted.
+    For convenience, isValid() returns true if the socket is ready for
+    reading and writing, but note that the socket's state must be
+    ConnectedState before reading and writing can occur.
+
+    Read or write data by calling read() or write(), or use the
+    convenience functions readLine() and readAll(). QAbstractSocket
+    also inherits getChar(), putChar(), and ungetChar() from
+    QIODevice, which work on single bytes. The bytesWritten() signal
+    is emitted when data has been written to the socket (i.e., when
+    the client has read the data). Note that Qt does not limit the
+    write buffer size. You can monitor its size by listening to this
+    signal.
+   
+    The readyRead() signal is emitted every time a new chunk of data
+    has arrived. bytesAvailable() then returns the number of bytes
+    that are available for reading. Typically, you would connect the
+    readyRead() signal to a slot and read all available data there.
+    If you don't read all the data at once, the remaining data will
+    still be available later, and any new incoming data will be
+    appended to QAbstractSocket's internal read buffer. To limit the
+    size of the read buffer, call setReadBufferSize().
+
+    To close the socket, call disconnectFromHost(). QAbstractSocket enters
+    QAbstractSocket::ClosingState. After all pending data has been written to
+    the socket, QAbstractSocket actually closes the socket, enters
+    QAbstractSocket::ClosedState, and emits disconnected(). If you want to
+    abort a connection immediately, discarding all pending data, call abort()
+    instead. If the remote host closes the connection, QAbstractSocket will
+    emit error(QAbstractSocket::RemoteHostClosedError), during which the socket
+    state will still be ConnectedState, and then the disconnected() signal
+    will be emitted.
+
+    The port and address of the connected peer is fetched by calling
+    peerPort() and peerAddress(). peerName() returns the host name of
+    the peer, as passed to connectToHost(). localPort() and
+    localAddress() return the port and address of the local socket.
+
+    QAbstractSocket provides a set of functions that suspend the
+    calling thread until certain signals are emitted. These functions
+    can be used to implement blocking sockets:
+
+    \list
+    \o waitForConnected() blocks until a connection has been established.
+
+    \o waitForReadyRead() blocks until new data is available for
+    reading.
+
+    \o waitForBytesWritten() blocks until one payload of data has been
+    written to the socket.
+
+    \o waitForDisconnected() blocks until the connection has closed.
+    \endlist
+
+    We show an example:
+
+    \snippet doc/src/snippets/network/tcpwait.cpp 0
+
+    If \l{QIODevice::}{waitForReadyRead()} returns false, the
+    connection has been closed or an error has occurred.
+
+    Programming with a blocking socket is radically different from
+    programming with a non-blocking socket. A blocking socket doesn't
+    require an event loop and typically leads to simpler code.
+    However, in a GUI application, blocking sockets should only be
+    used in non-GUI threads, to avoid freezing the user interface.
+    See the \l network/fortuneclient and \l network/blockingfortuneclient
+    examples for an overview of both approaches.
+
+    QAbstractSocket can be used with QTextStream and QDataStream's
+    stream operators (operator<<() and operator>>()). There is one
+    issue to be aware of, though: You must make sure that enough data
+    is available before attempting to read it using operator>>().
+
+    \sa QFtp, QHttp, QTcpServer
+*/
+
+/*!
+    \fn void QAbstractSocket::hostFound()
+
+    This signal is emitted after connectToHost() has been called and
+    the host lookup has succeeded.
+
+    \sa connected()
+*/
+
+/*!
+    \fn void QAbstractSocket::connected()
+
+    This signal is emitted after connectToHost() has been called and
+    a connection has been successfully established.
+
+    \sa connectToHost(), disconnected()
+*/
+
+/*!
+    \fn void QAbstractSocket::disconnected()
+
+    This signal is emitted when the socket has been disconnected.
+    
+    \warning If you need to delete the sender() of this signal in a slot connected
+    to it, use the \l{QObject::deleteLater()}{deleteLater()} function.
+
+    \sa connectToHost(), disconnectFromHost(), abort()
+*/
+
+/*!
+    \fn void QAbstractSocket::error(QAbstractSocket::SocketError socketError)
+
+    This signal is emitted after an error occurred. The \a socketError
+    parameter describes the type of error that occurred.
+
+    QAbstractSocket::SocketError is not a registered metatype, so for queued
+    connections, you will have to register it with Q_REGISTER_METATYPE.
+
+    \sa error(), errorString()
+*/
+
+/*!
+    \fn void QAbstractSocket::stateChanged(QAbstractSocket::SocketState socketState)
+
+    This signal is emitted whenever QAbstractSocket's state changes.
+    The \a socketState parameter is the new state.
+
+    QAbstractSocket::SocketState is not a registered metatype, so for queued
+    connections, you will have to register it with Q_REGISTER_METATYPE.
+
+    \sa state()
+*/
+
+/*!
+    \fn void QAbstractSocket::proxyAuthenticationRequired(const QNetworkProxy &proxy, QAuthenticator *authenticator)
+    \since 4.3
+
+    This signal can be emitted when a \a proxy that requires
+    authentication is used. The \a authenticator object can then be
+    filled in with the required details to allow authentication and
+    continue the connection.
+
+    \note It is not possible to use a QueuedConnection to connect to
+    this signal, as the connection will fail if the authenticator has
+    not been filled in with new information when the signal returns.
+
+    \sa QAuthenticator, QNetworkProxy
+*/
+
+/*!
+    \enum QAbstractSocket::NetworkLayerProtocol
+
+    This enum describes the network layer protocol values used in Qt.
+
+    \value IPv4Protocol IPv4
+    \value IPv6Protocol IPv6
+    \value UnknownNetworkLayerProtocol Other than IPv4 and IPv6
+
+    \sa QHostAddress::protocol()
+*/
+
+/*!
+    \enum QAbstractSocket::SocketType
+
+    This enum describes the transport layer protocol.
+
+    \value TcpSocket TCP
+    \value UdpSocket UDP
+    \value UnknownSocketType Other than TCP and UDP
+
+    \sa QAbstractSocket::socketType()
+*/
+
+/*!
+    \enum QAbstractSocket::SocketError
+
+    This enum describes the socket errors that can occur.
+
+    \value ConnectionRefusedError The connection was refused by the
+           peer (or timed out).
+    \value RemoteHostClosedError The remote host closed the
+           connection. Note that the client socket (i.e., this socket)
+           will be closed after the remote close notification has
+           been sent.
+    \value HostNotFoundError The host address was not found.
+    \value SocketAccessError The socket operation failed because the
+           application lacked the required privileges.
+    \value SocketResourceError The local system ran out of resources
+           (e.g., too many sockets).
+    \value SocketTimeoutError The socket operation timed out.
+    \value DatagramTooLargeError The datagram was larger than the
+           operating system's limit (which can be as low as 8192
+           bytes).
+    \value NetworkError An error occurred with the network (e.g., the
+           network cable was accidentally plugged out).
+    \value AddressInUseError The address specified to QUdpSocket::bind() is
+           already in use and was set to be exclusive.
+    \value SocketAddressNotAvailableError The address specified to
+           QUdpSocket::bind() does not belong to the host.
+    \value UnsupportedSocketOperationError The requested socket operation is
+           not supported by the local operating system (e.g., lack of
+           IPv6 support).
+    \value ProxyAuthenticationRequiredError The socket is using a proxy, and
+           the proxy requires authentication.
+    \value SslHandshakeFailedError The SSL/TLS handshake failed, so
+           the connection was closed (only used in QSslSocket)
+    \value UnfinishedSocketOperationError Used by QAbstractSocketEngine only,
+           The last operation attempted has not finished yet (still in progress in
+            the background).
+    \value ProxyConnectionRefusedError Could not contact the proxy server because
+           the connection to that server was denied
+    \value ProxyConnectionClosedError The connection to the proxy server was closed
+           unexpectedly (before the connection to the final peer was established)
+    \value ProxyConnectionTimeoutError The connection to the proxy server timed out
+           or the proxy server stopped responding in the authentication phase.
+    \value ProxyNotFoundError The proxy address set with setProxy() (or the application
+           proxy) was not found.
+    \value ProxyProtocolError The connection negotiation with the proxy server
+           because the response from the proxy server could not be understood.
+
+    \value UnknownSocketError An unidentified error occurred.
+    \sa QAbstractSocket::error()
+*/
+
+/*!
+    \enum QAbstractSocket::SocketState
+
+    This enum describes the different states in which a socket can be.
+
+    \value UnconnectedState The socket is not connected.
+    \value HostLookupState The socket is performing a host name lookup.
+    \value ConnectingState The socket has started establishing a connection.
+    \value ConnectedState A connection is established.
+    \value BoundState The socket is bound to an address and port (for servers).
+    \value ClosingState The socket is about to close (data may still
+    be waiting to be written).
+    \value ListeningState For internal use only.
+    \omitvalue Idle
+    \omitvalue HostLookup
+    \omitvalue Connecting
+    \omitvalue Connected
+    \omitvalue Closing
+    \omitvalue Connection
+
+    \sa QAbstractSocket::state()
+*/
+
+#include "qabstractsocket.h"
+#include "qabstractsocket_p.h"
+
+#include <qabstracteventdispatcher.h>
+#include <qdatetime.h>
+#include <qhostaddress.h>
+#include <qhostinfo.h>
+#include <qmetaobject.h>
+#include <qpointer.h>
+#include <qtimer.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;
+    }
+}
+
+/*! \internal
+
+    Constructs a QAbstractSocketPrivate. Initializes all members.
+*/
+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),
+      connectTimeElapsed(0),
+      hostLookupId(-1),
+      state(QAbstractSocket::UnconnectedState),
+      socketError(QAbstractSocket::UnknownSocketError)
+{
+}
+
+/*! \internal
+
+    Destructs the QAbstractSocket. If the socket layer is open, it
+    will be reset.
+*/
+QAbstractSocketPrivate::~QAbstractSocketPrivate()
+{
+}
+
+/*! \internal
+
+    Resets the socket layer, clears the read and write buffers and
+    deletes any socket notifiers.
+*/
+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();
+    }
+}
+
+/*! \internal
+
+    Initializes the socket layer to by of type \a type, using the
+    network layer protocol \a protocol. Resets the socket layer first
+    if it's already initialized. Sets up the socket notifiers.
+*/
+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 = "TcpSocket";
+    else if (q->socketType() == QAbstractSocket::UdpSocket) typeStr = "UdpSocket";
+    else typeStr = "UnknownSocketType";
+    QString protocolStr;
+    if (protocol == QAbstractSocket::IPv4Protocol) protocolStr = "IPv4Protocol";
+    else if (protocol == QAbstractSocket::IPv6Protocol) protocolStr = "IPv6Protocol";
+    else protocolStr = "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;
+    }
+    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;
+}
+
+/*! \internal
+
+    Slot connected to the read socket notifier. This slot is called
+    when new data is available for reading, or when the socket has
+    been closed. Handles recursive calls.
+*/
+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);
+        }
+    }
+    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
+            readSocketNotifierCalled = false;
+            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();
+            readSocketNotifierCalled = false;
+            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 && socketEngine && socketEngine->hasPendingDatagrams())
+#endif
+        ;
+
+    if (!emittedReadyRead && hasData) {
+        emittedReadyRead = true;
+        emit q->readyRead();
+        emittedReadyRead = false;
+    }
+
+    // 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
+        readSocketNotifierCalled = false;
+        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;
+    }
+    readSocketNotifierCalled = false;
+    return true;
+}
+
+/*! \internal
+
+    Slot connected to the write socket notifier. It's called during a
+    delayed connect or when the socket is ready for writing.
+*/
+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->setWriteNotificationEnabled(false);
+#endif
+    }
+
+    return (writeBuffer.size() < tmp);
+}
+
+/*! \internal
+
+    Slot connected to a notification of connection status
+    change. Either we finished connecting or we failed to connect.
+*/
+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();
+    }
+}
+
+/*! \internal
+
+    Writes pending data in the write buffers to the socket. The
+    function writes as much as it can without blocking.
+
+    It is usually invoked by canWriteNotification after one or more
+    calls to write().
+
+    Emits bytesWritten().
+*/
+bool QAbstractSocketPrivate::flush()
+{
+    Q_Q(QAbstractSocket);
+    if (!socketEngine || !socketEngine->isValid() || writeBuffer.isEmpty()) {
+#if defined (QABSTRACTSOCKET_DEBUG)
+    qDebug("QAbstractSocketPrivate::flush() nothing to do: valid ? %s, writeBuffer.isEmpty() ? %s",
+           socketEngine->isValid() ? "yes" : "no", writeBuffer.isEmpty() ? "yes" : "no");
+#endif
+        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());
+        emit q->error(socketError);
+        // an unexpected error so close the socket.
+#if defined (QABSTRACTSOCKET_DEBUG)
+        qDebug() << "QAbstractSocketPrivate::flush() write error, aborting." << socketEngine->errorString();
+#endif
+        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) {
+            emittedBytesWritten = true;
+            emit q->bytesWritten(written);
+            emittedBytesWritten = false;
+        }
+    }
+
+    if (writeBuffer.isEmpty() && socketEngine && socketEngine->isWriteNotificationEnabled())
+        socketEngine->setWriteNotificationEnabled(false);
+    if (state == QAbstractSocket::ClosingState)
+        q->disconnectFromHost();
+
+    return true;
+}
+
+#ifndef QT_NO_NETWORKPROXY
+/*! \internal
+
+    Resolve the proxy to its final value.
+*/
+void QAbstractSocketPrivate::resolveProxy(const QString &hostname, quint16 port)
+{
+    QHostAddress parsed;
+    if (hostname == QLatin1String("localhost")
+        || hostname.startsWith(QLatin1String("localhost."))
+        || (parsed.setAddress(hostname)
+            && (parsed == QHostAddress::LocalHost
+                || parsed == QHostAddress::LocalHostIPv6))) {
+        proxyInUse = QNetworkProxy::NoProxy;
+        return;
+    }
+
+    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();
+}
+
+/*!
+    \internal
+
+    Starts the connection to \a host, like _q_startConnecting below,
+    but without hostname resolution.
+*/
+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
+
+/*! \internal
+
+    Slot connected to QHostInfo::lookupHost() in connectToHost(). This
+    function starts the process of connecting to any number of
+    candidate IP addresses for the host, if it was found. Calls
+    _q_connectToNextAddress().
+*/
+void QAbstractSocketPrivate::_q_startConnecting(const QHostInfo &hostInfo)
+{
+    Q_Q(QAbstractSocket);
+    if (state != QAbstractSocket::HostLookupState)
+        return;
+
+    addresses = hostInfo.addresses();
+
+#if defined(QABSTRACTSOCKET_DEBUG)
+    QString s = "{";
+    for (int i = 0; i < addresses.count(); ++i) {
+        if (i != 0) s += ", ";
+        s += addresses.at(i).toString();
+    }
+    s += "}";
+    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();
+}
+
+/*! \internal
+
+    Called by a queued or direct connection from _q_startConnecting() or
+    _q_testConnection(), this function takes the first address of the
+    pending addresses list and tries to connect to it. If the
+    connection succeeds, QAbstractSocket will emit
+    connected(). Otherwise, error(ConnectionRefusedError) or
+    error(SocketTimeoutError) is emitted.
+*/
+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);
+}
+
+/*! \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 (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();
+}
+
+/*! \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()
+{
+    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();
+    }
+}
+
+/*! \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.,
+    "qtsoftware.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",
+                              Qt::DirectConnection,
+                              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)...", qPrintable(hostName), port,
+           (int) openMode);
+#endif
+
+    if (d->state == ConnectedState || d->state == ConnectingState) {
+        qWarning("QAbstractSocket::connectToHost() called when already 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;
+#ifdef Q_OS_LINUX
+    // ### See setSocketDescriptor().
+    d->addToBytesAvailable = 0;
+#endif
+    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 (!d_func()->isBuffered)
+        openMode |= QAbstractSocket::Unbuffered;
+    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)
+            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)
+    qDebug("QAbstractSocket::bytesToWrite() == %i", d->writeBuffer.size());
+#endif
+    return (qint64)d->writeBuffer.size();
+}
+
+/*!
+    Returns the number of incoming bytes that are waiting to be read.
+
+    \sa bytesToWrite(), read()
+*/
+qint64 QAbstractSocket::bytesAvailable() const
+{
+    Q_D(const QAbstractSocket);
+    qint64 available = QIODevice::bytesAvailable();
+    if (d->isBuffered)
+        available += (qint64) d->readBuffer.size();
+    else if (d->socketEngine && d->socketEngine->isValid())
+        available += d->socketEngine->bytesAvailable();
+#if defined(QABSTRACTSOCKET_DEBUG)
+    qDebug("QAbstractSocket::bytesAvailable() == %llu", available);
+#endif
+    return available;
+}
+
+/*!
+    Returns the host port number (in native byte order) of the local
+    socket if available; otherwise returns 0.
+
+    \sa localAddress(), peerPort(), setLocalPort()
+*/
+quint16 QAbstractSocket::localPort() const
+{
+    Q_D(const QAbstractSocket);
+    return d->localPort;
+}
+
+/*!
+    Returns the host address of the local socket if available;
+    otherwise returns QHostAddress::Null.
+
+    This is normally the main IP address of the host, but can be
+    QHostAddress::LocalHost (127.0.0.1) for connections to the
+    local host.
+
+    \sa localPort(), peerAddress(), setLocalAddress()
+*/
+QHostAddress QAbstractSocket::localAddress() const
+{
+    Q_D(const QAbstractSocket);
+    return d->localAddress;
+}
+
+/*!
+    Returns the port of the connected peer if the socket is in
+    ConnectedState; otherwise returns 0.
+
+    \sa peerAddress(), localPort(), setPeerPort()
+*/
+quint16 QAbstractSocket::peerPort() const
+{
+    Q_D(const QAbstractSocket);
+    return d->peerPort;
+}
+
+/*!
+    Returns the address of the connected peer if the socket is in
+    ConnectedState; otherwise returns QHostAddress::Null.
+
+    \sa peerName(), peerPort(), localAddress(), setPeerAddress()
+*/
+QHostAddress QAbstractSocket::peerAddress() const
+{
+    Q_D(const QAbstractSocket);
+    return d->peerAddress;
+}
+
+/*!
+    Returns the name of the peer as specified by connectToHost(), or
+    an empty QString if connectToHost() has not been called.
+
+    \sa peerAddress(), peerPort(), setPeerName()
+*/
+QString QAbstractSocket::peerName() const
+{
+    Q_D(const QAbstractSocket);
+    return d->peerName.isEmpty() ? d->hostName : d->peerName;
+}
+
+/*!
+    Returns true if a line of data can be read from the socket;
+    otherwise returns false.
+
+    \sa readLine()
+*/
+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();
+}
+
+/*!
+    Returns the native socket descriptor of the QAbstractSocket object
+    if this is available; otherwise returns -1.
+
+    If the socket is using QNetworkProxy, the returned descriptor
+    may not be usable with native socket functions.
+
+    The socket descriptor is not available when QAbstractSocket is in
+    UnconnectedState.
+
+    \sa setSocketDescriptor()
+*/
+int QAbstractSocket::socketDescriptor() const
+{
+    Q_D(const QAbstractSocket);
+    return d->cachedSocketDescriptor;
+}
+
+/*!
+    Initializes QAbstractSocket with the native socket descriptor \a
+    socketDescriptor. Returns true if \a socketDescriptor is accepted
+    as a valid socket descriptor; otherwise returns false.
+    The socket is opened in the mode specified by \a openMode, and
+    enters the socket state specified by \a socketState.
+
+    \bold{Note:} It is not possible to initialize two abstract sockets
+    with the same native socket descriptor.
+
+    \sa socketDescriptor()
+*/
+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;
+    }
+    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;
+
+#ifdef Q_OS_LINUX
+    // ### This is a workaround for certain broken Linux kernels, when using
+    // QTcpSocket with a Unix domain socket. It was introduced around 2.6.9,
+    // and fixed at some point after that.
+    // http://archive.linux-usenet.com/index-t-73300.html
+    // We can provide a better workaround for this: readFromSocket() can loop
+    // while reading, but this must happen without triggering an implicit
+    // close because of reading after the socket has closed.
+    d->addToBytesAvailable = 4096;
+#endif
+
+    return true;
+}
+
+/*
+   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;
+}
+
+/*!
+    Waits until the socket is connected, up to \a msecs
+    milliseconds. If the connection has been established, this
+    function returns true; otherwise it returns false. In the case
+    where it returns false, you can call error() to determine
+    the cause of the error.
+
+    The following example waits up to one second for a connection
+    to be established:
+
+    \snippet doc/src/snippets/code/src_network_socket_qabstractsocket.cpp 0
+
+    If msecs is -1, this function will not time out.
+
+    Note: This function may wait slightly longer than \a msecs,
+    depending on the time it takes to complete the host lookup.
+
+    \sa connectToHost(), connected()
+*/
+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;
+    QTime 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;
+        d->_q_startConnecting(QHostInfo::fromName(d->hostName));
+    }
+    if (state() == UnconnectedState)
+        return false;
+
+    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;
+}
+
+/*!
+    This function blocks until data is available for reading and the
+    \l{QIODevice::}{readyRead()} signal has been emitted. The function
+    will timeout after \a msecs milliseconds; the default timeout is
+    30000 milliseconds.
+
+    The function returns true if the readyRead() signal is emitted and
+    there is data available for reading; otherwise it returns false
+    (if an error occurred or the operation timed out).
+
+    \sa waitForBytesWritten() 
+*/
+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;
+    }
+
+    QTime stopWatch;
+    stopWatch.start();
+
+    // handle a socket in connecting state
+    if (state() == HostLookupState || state() == ConnectingState) {
+        if (!waitForConnected(msecs))
+            return false;
+    }
+
+    Q_ASSERT(d->socketEngine);
+    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::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;
+    }
+    return false;
+}
+
+/*! \reimp
+ */
+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;
+
+    QTime 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;
+}
+
+/*!
+    Waits until the socket has disconnected, up to \a msecs
+    milliseconds. If the connection has been disconnected, this
+    function returns true; otherwise it returns false. In the case
+    where it returns false, you can call error() to determine
+    the cause of the error.
+
+    The following example waits up to one second for a connection
+    to be closed:
+
+    \snippet doc/src/snippets/code/src_network_socket_qabstractsocket.cpp 1
+
+    If msecs is -1, this function will not time out.
+
+    \sa disconnectFromHost(), close()
+*/
+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;
+    }
+
+    QTime 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;
+}
+
+/*!
+    Aborts the current connection and resets the socket. Unlike
+    disconnectFromHost(), this function immediately closes the socket, discarding
+    any pending data in the write buffer.
+
+    \sa disconnectFromHost(), close()
+*/
+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();
+}
+
+/*! \reimp
+*/
+bool QAbstractSocket::isSequential() const
+{
+    return true;
+}
+
+/*! \reimp
+
+     Returns true if no more data is currently
+     available for reading; otherwise returns false.
+
+     This function is most commonly used when reading data from the
+     socket in a loop. For example:
+
+     \snippet doc/src/snippets/code/src_network_socket_qabstractsocket.cpp 2
+
+     \sa bytesAvailable(), readyRead()
+ */
+bool QAbstractSocket::atEnd() const
+{
+    return QIODevice::atEnd() && (!isOpen() || d_func()->readBuffer.isEmpty());
+}
+
+/*!
+    This function writes as much as possible from the internal write buffer to
+    the underlying network socket, without blocking. If any data was written,
+    this function returns true; otherwise false is returned.
+
+    Call this function if you need QAbstractSocket to start sending buffered
+    data immediately. The number of bytes successfully written depends on the
+    operating system. In most cases, you do not need to call this function,
+    because QAbstractSocket will start sending data automatically once control
+    goes back to the event loop. In the absence of an event loop, call
+    waitForBytesWritten() instead.
+
+    \sa write(), waitForBytesWritten()
+*/
+// 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();
+}
+
+/*! \reimp
+*/
+qint64 QAbstractSocket::readData(char *data, qint64 maxSize)
+{
+    Q_D(QAbstractSocket);
+    if (d->socketEngine && !d->socketEngine->isReadNotificationEnabled() && d->socketEngine->isValid())
+        d->socketEngine->setReadNotificationEnabled(true);
+
+    if (!d->isBuffered) {
+        if (!d->socketEngine)
+            return -1;          // no socket engine is probably EOF
+        qint64 readBytes = d->socketEngine->read(data, maxSize);
+        if (readBytes < 0) {
+            d->socketError = d->socketEngine->error();
+            setErrorString(d->socketEngine->errorString());
+        }
+        if (!d->socketEngine->isReadNotificationEnabled())
+            d->socketEngine->setReadNotificationEnabled(true);
+#if defined (QABSTRACTSOCKET_DEBUG)
+        qDebug("QAbstractSocket::readData(%p \"%s\", %lli) == %lld",
+               data, qt_prettyDebug(data, 32, readBytes).data(), maxSize,
+               readBytes);
+#endif
+        return readBytes;
+    }
+
+    if (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);
+
+    // If readFromSocket() read data, copy it to its destination.
+    if (maxSize == 1) {
+        *data = d->readBuffer.getChar();
+#if defined (QABSTRACTSOCKET_DEBUG)
+        qDebug("QAbstractSocket::readData(%p '%c (0x%.2x)', 1) == 1",
+               data, isprint(int(uchar(*data))) ? *data : '?', *data);
+#endif
+        return 1;
+    }
+
+    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 defined (QABSTRACTSOCKET_DEBUG)
+    qDebug("QAbstractSocket::readData(%p \"%s\", %lli) == %lld",
+           data, qt_prettyDebug(data, qMin<qint64>(32, readSoFar), readSoFar).data(),
+           maxSize, readSoFar);
+#endif
+    return readSoFar;
+}
+
+/*! \reimp
+*/
+qint64 QAbstractSocket::readLineData(char *data, qint64 maxlen)
+{
+    return QIODevice::readLineData(data, maxlen);
+}
+
+/*! \reimp
+*/
+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) {
+        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;
+    }
+
+    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;
+}
+
+/*!
+    \since 4.1
+
+    Sets the port on the local side of a connection to \a port.
+
+    You can call this function in a subclass of QAbstractSocket to
+    change the return value of the localPort() function after a
+    connection has been established. This feature is commonly used by
+    proxy connections for virtual connection settings.
+
+    Note that this function does not bind the local port of the socket
+    prior to a connection (e.g., QUdpSocket::bind()).
+
+    \sa localAddress(), setLocalAddress(), setPeerPort()
+*/
+void QAbstractSocket::setLocalPort(quint16 port)
+{
+    Q_D(QAbstractSocket);
+    d->localPort = port;
+}
+
+/*!
+    \since 4.1
+
+    Sets the address on the local side of a connection to
+    \a address.
+
+    You can call this function in a subclass of QAbstractSocket to
+    change the return value of the localAddress() function after a
+    connection has been established. This feature is commonly used by
+    proxy connections for virtual connection settings.
+
+    Note that this function does not bind the local address of the socket
+    prior to a connection (e.g., QUdpSocket::bind()).
+
+    \sa localAddress(), setLocalPort(), setPeerAddress()
+*/
+void QAbstractSocket::setLocalAddress(const QHostAddress &address)
+{
+    Q_D(QAbstractSocket);
+    d->localAddress = address;
+}
+
+/*!
+    \since 4.1
+
+    Sets the port of the remote side of the connection to
+    \a port.
+
+    You can call this function in a subclass of QAbstractSocket to
+    change the return value of the peerPort() function after a
+    connection has been established. This feature is commonly used by
+    proxy connections for virtual connection settings.
+
+    \sa peerPort(), setPeerAddress(), setLocalPort()
+*/
+void QAbstractSocket::setPeerPort(quint16 port)
+{
+    Q_D(QAbstractSocket);
+    d->peerPort = port;
+}
+
+/*!
+    \since 4.1
+
+    Sets the address of the remote side of the connection
+    to \a address.
+
+    You can call this function in a subclass of QAbstractSocket to
+    change the return value of the peerAddress() function after a
+    connection has been established. This feature is commonly used by
+    proxy connections for virtual connection settings.
+
+    \sa peerAddress(), setPeerPort(), setLocalAddress()
+*/
+void QAbstractSocket::setPeerAddress(const QHostAddress &address)
+{
+    Q_D(QAbstractSocket);
+    d->peerAddress = address;
+}
+
+/*!
+    \since 4.1
+
+    Sets the host name of the remote peer to \a name.
+
+    You can call this function in a subclass of QAbstractSocket to
+    change the return value of the peerName() function after a
+    connection has been established. This feature is commonly used by
+    proxy connections for virtual connection settings.
+
+    \sa peerName()
+*/
+void QAbstractSocket::setPeerName(const QString &name)
+{
+    Q_D(QAbstractSocket);
+    d->peerName = name;
+}
+
+/*!
+    Disconnects the socket's connection with the host.
+
+    \sa abort()
+*/
+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;
+}
+
+/*!
+    Attempts to close the socket. If there is pending data waiting to
+    be written, QAbstractSocket will enter ClosingState and wait
+    until all data has been written. Eventually, it will enter
+    UnconnectedState and emit the disconnected() signal.
+
+    \sa connectToHost()
+*/
+void QAbstractSocket::disconnectFromHost()
+{
+    QMetaObject::invokeMethod(this, "disconnectFromHostImplementation",
+                              Qt::DirectConnection);
+}
+
+/*!
+    \since 4.1
+
+    Contains the implementation of disconnectFromHost().
+*/
+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
+    } 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->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 || 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();
+    }
+}
+
+/*!
+    Returns the size of the internal read buffer. This limits the
+    amount of data that the client can receive before you call read()
+    or readAll().
+
+    A read buffer size of 0 (the default) means that the buffer has
+    no size limit, ensuring that no data is lost.
+
+    \sa setReadBufferSize(), read()
+*/
+qint64 QAbstractSocket::readBufferSize() const
+{
+    return d_func()->readBufferMaxSize;
+}
+
+/*!
+    Sets the size of QAbstractSocket's internal read buffer to be \a
+    size bytes.
+
+    If the buffer size is limited to a certain size, QAbstractSocket
+    won't buffer more than this size of data. Exceptionally, a buffer
+    size of 0 means that the read buffer is unlimited and all
+    incoming data is buffered. This is the default.
+
+    This option is useful if you only read the data at certain points
+    in time (e.g., in a real-time streaming application) or if you
+    want to protect your socket against receiving too much data,
+    which may eventually cause your application to run out of memory.
+
+    Only QTcpSocket uses QAbstractSocket's internal buffer; QUdpSocket
+    does not use any buffering at all, but rather relies on the
+    implicit buffering provided by the operating system.
+    Because of this, calling this function on QUdpSocket has no
+    effect.
+
+    \sa readBufferSize(), read()
+*/
+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->socketEngine->setReadNotificationEnabled(true);
+    }
+}
+
+/*!
+    Returns the state of the socket.
+
+    \sa error()
+*/
+QAbstractSocket::SocketState QAbstractSocket::state() const
+{
+    return d_func()->state;
+}
+
+/*!
+    Sets the state of the socket to \a state.
+
+    \sa state()
+*/
+void QAbstractSocket::setSocketState(SocketState state)
+{
+    d_func()->state = state;
+}
+
+/*!
+    Returns the socket type (TCP, UDP, or other).
+
+    \sa QTcpSocket, QUdpSocket
+*/
+QAbstractSocket::SocketType QAbstractSocket::socketType() const
+{
+    return d_func()->socketType;
+}
+
+/*!
+    Returns the type of error that last occurred.
+
+    \sa state(), errorString()
+*/
+QAbstractSocket::SocketError QAbstractSocket::error() const
+{
+    return d_func()->socketError;
+}
+
+/*!
+    Sets the type of error that last occurred to \a socketError.
+
+    \sa setSocketState(), setErrorString()
+*/
+void QAbstractSocket::setSocketError(SocketError socketError)
+{
+    d_func()->socketError = socketError;
+}
+
+#ifndef QT_NO_NETWORKPROXY
+/*!
+    \since 4.1
+
+    Sets the explicit network proxy for this socket to \a networkProxy.
+
+    To disable the use of a proxy for this socket, use the
+    QNetworkProxy::NoProxy proxy type:
+
+    \snippet doc/src/snippets/code/src_network_socket_qabstractsocket.cpp 3
+
+    The default value for the proxy is QNetworkProxy::DefaultProxy,
+    which means the socket will use the application settings: if a
+    proxy is set with QNetworkProxy::setApplicationProxy, it will use
+    that; otherwise, if a factory is set with
+    QNetworkProxyFactory::setApplicationProxyFactory, it will query
+    that factory with type QNetworkProxyQuery::TcpSocket.
+
+    \sa proxy(), QNetworkProxy, QNetworkProxyFactory::queryProxy()
+*/
+void QAbstractSocket::setProxy(const QNetworkProxy &networkProxy)
+{
+    Q_D(QAbstractSocket);
+    d->proxy = networkProxy;
+}
+
+/*!
+    \since 4.1
+
+    Returns the network proxy for this socket.
+    By default QNetworkProxy::DefaultProxy is used, which means this
+    socket will query the default proxy settings for the application.
+
+    \sa setProxy(), QNetworkProxy, QNetworkProxyFactory
+*/
+QNetworkProxy QAbstractSocket::proxy() const
+{
+    Q_D(const QAbstractSocket);
+    return d->proxy;
+}
+#endif // QT_NO_NETWORKPROXY
+
+#ifdef QT3_SUPPORT
+/*! \enum QAbstractSocket::Error
+    \compat
+
+    Use QAbstractSocket::SocketError instead.
+
+    \value ErrConnectionRefused Use QAbstractSocket::ConnectionRefusedError instead.
+    \value ErrHostNotFound Use QAbstractSocket::HostNotFoundError instead.
+    \value ErrSocketRead Use QAbstractSocket::UnknownSocketError instead.
+*/
+
+/*!
+    \typedef QAbstractSocket::State
+    \compat
+
+    Use QAbstractSocket::SocketState instead.
+
+    \table
+    \header \o Qt 3 enum value \o Qt 4 enum value
+    \row \o \c Idle            \o \l UnconnectedState
+    \row \o \c HostLookup      \o \l HostLookupState
+    \row \o \c Connecting      \o \l ConnectingState
+    \row \o \c Connected       \o \l ConnectedState
+    \row \o \c Closing         \o \l ClosingState
+    \row \o \c Connection      \o \l ConnectedState
+    \endtable
+*/
+
+/*!
+    \fn int QAbstractSocket::socket() const
+
+    Use socketDescriptor() instead.
+*/
+
+/*!
+    \fn void QAbstractSocket::setSocket(int socket)
+
+    Use setSocketDescriptor() instead.
+*/
+
+/*!
+    \fn Q_ULONG QAbstractSocket::waitForMore(int msecs, bool *timeout = 0) const
+
+    Use waitForReadyRead() instead.
+
+    \oldcode
+        bool timeout;
+        Q_ULONG numBytes = socket->waitForMore(30000, &timeout);
+    \newcode
+        qint64 numBytes = 0;
+        if (socket->waitForReadyRead(msecs))
+            numBytes = socket->bytesAvailable();
+        bool timeout = (error() == QAbstractSocket::SocketTimeoutError);
+    \endcode
+
+    \sa waitForReadyRead(), bytesAvailable(), error(), SocketTimeoutError
+*/
+
+/*!
+    \fn void QAbstractSocket::connectionClosed()
+
+    Use disconnected() instead.
+*/
+
+/*!
+    \fn void QAbstractSocket::delayedCloseFinished()
+
+    Use disconnected() instead.
+*/
+#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"