qabstractsocket.cpp

奇趣公司比较新的qt/emd版本

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//#define QABSTRACTSOCKET_DEBUG

/*!
    \class QAbstractSocket

    \brief The QAbstractSocket class provides the base functionality
    common to all socket types.

    \reentrant
    \ingroup io
    \module network

    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. For every chunk of data
    that has been written to the socket, the bytesWritten() signal is
    emitted.

    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, then emits closing(). 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:

    \quotefromfile snippets/network/tcpwait.cpp
    \skipto numRead
    \printuntil /^\s\s\s\s\}/

    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.

    \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 UnknownSocketError An unidentified error occurred.

    \omitvalue UnfinishedSocketOperationError Used by QAbstractSocketEngine only,
           this error indicates that the last operation could not complete.

    \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)

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

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

/*
    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

/*! \internal

    Constructs a QAbstractSocketPrivate. Initializes all members.
*/
QAbstractSocketPrivate::QAbstractSocketPrivate()
    : readSocketNotifierCalled(false),
      readSocketNotifierState(false),
      readSocketNotifierStateSet(false),
      emittedReadyRead(false),
      emittedBytesWritten(false),
      closeCalled(false),
      port(0),
      localPort(0),
      peerPort(0),
      socketEngine(0),
      cachedSocketDescriptor(-1),
      readBufferMaxSize(0),
      readBuffer(QABSTRACTSOCKET_BUFFERSIZE),
      writeBuffer(QABSTRACTSOCKET_BUFFERSIZE),