qiodevice.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

#ifdef Q_OS_WIN
    if (d->openMode & Text) {
        const char *endOfData = data + maxSize;
        const char *startOfBlock = data;

        qint64 writtenSoFar = 0;

        forever {
            const char *endOfBlock = startOfBlock;
            while (endOfBlock < endOfData && *endOfBlock != '\n')
                ++endOfBlock;

            qint64 blockSize = endOfBlock - startOfBlock;
            if (blockSize > 0) {
                qint64 ret = writeData(startOfBlock, blockSize);
                if (ret <= 0) {
                    if (writtenSoFar)
                        d->ungetBuffer.chop(writtenSoFar);
                    return writtenSoFar ? writtenSoFar : ret;
                }
                writtenSoFar += ret;
            }

            if (endOfBlock == endOfData)
                break;

            qint64 ret = writeData("\r\n", 2);
            if (ret <= 0) {
                if (writtenSoFar)
                    d->ungetBuffer.chop(writtenSoFar);
                return writtenSoFar ? writtenSoFar : ret;
            }
            ++writtenSoFar;

            startOfBlock = endOfBlock + 1;
        }

        if (writtenSoFar)
            d->ungetBuffer.chop(writtenSoFar);
        return writtenSoFar;
    }
#endif
    qint64 written = writeData(data, maxSize);
    if (written > 0 && !d->ungetBuffer.isEmpty())
        d->ungetBuffer.chop(written);
    return written;
}

/*! \fn qint64 QIODevice::write(const QByteArray &byteArray)

    \overload

    Writes the content of \a byteArray to the device. Returns the number of
    bytes that were actually written, or -1 if an error occurred.

    \sa read() writeData()
*/

/*! \fn bool QIODevice::putChar(char c)

    Writes the character \a c to the device. Returns true on success;
    otherwise returns false.

    \sa write() getChar() ungetChar()
*/

/*!
    Puts the character \a c back into the device, and decrements the
    current position unless the position is 0. This function is
    usually called to "undo" a getChar() operation, such as when
    writing a backtracking parser.

    If \a c was not previously read from the device, the behavior is
    undefined.
*/
void QIODevice::ungetChar(char c)
{
    Q_D(QIODevice);
    CHECK_OPEN(write, Q_VOID);
    CHECK_READABLE(read, Q_VOID);
    d->ungetBuffer.append(c);
    if (!isSequential()) {
        qint64 curPos = pos();
        if (curPos > 0) {
            QByteArray tmp = d->ungetBuffer;
            seek(curPos - 1);
            d->ungetBuffer = tmp;
        }
    }
}

/*!
    \since 4.1

    Reads at most \a maxSize bytes from the device into \a data, without side
    effects (i.e., if you call read() after peek(), you will get the same
    data).  Returns the number of bytes read. If an error occurs, such as
    when attempting to peek a device opened in WriteOnly mode, this function
    returns -1.

    0 is returned when no more data is available for reading.

    Example:

    \code
        bool isExeFile(QFile *file)
        {
            char buf[2];
            if (file->peek(buf, sizeof(buf)) == sizeof(buf))
                return (buf[0] == 'M' && buf[1] == 'Z');
            return false;
        }
    \endcode

    \sa read()
*/
qint64 QIODevice::peek(char *data, qint64 maxSize)
{
    qint64 oldPos = pos();
    qint64 readBytes = read(data, maxSize);
    if (isSequential()) {
        int i = readBytes;
        while (i > 0)
            ungetChar(data[i-- - 1]);
    } else {
        seek(oldPos);
    }
    return readBytes;
}

/*!
    \since 4.1
    \overload

    Peeks at most \a maxSize bytes from the device, returning the data peeked
    as a QByteArray.

    Example:

    \code
        bool isExeFile(QFile *file)
        {
            return file->peek(2) == "MZ";
        }
    \endcode

    This function has no way of reporting errors; returning an empty
    QByteArray() can mean either that no data was currently available
    for peeking, or that an error occurred.

    \sa read()
*/
QByteArray QIODevice::peek(qint64 maxSize)
{
    qint64 oldPos = pos();
    QByteArray result = read(maxSize);
    if (isSequential()) {
        int i = result.size();
        const char *data = result.constData();
        while (i > 0)
            ungetChar(data[i-- - 1]);
    } else {
        seek(oldPos);
    }
    return result;
}

/*!
    Blocks until data is available for reading and the readyRead()
    signal has been emitted, or until \a msecs milliseconds have
    passed. If msecs is -1, this function will not time out.

    Returns true if data is available for reading; otherwise returns
    false (if the operation timed out or if an error occurred).

    This function can operate without an event loop. It is
    useful when writing non-GUI applications and when performing
    I/O operations in a non-GUI thread.

    If called from within a slot connected to the readyRead() signal,
    readyRead() will not be reemitted.

    \warning Calling this function from the main (GUI) thread
    might cause your user interface to freeze.

    \sa waitForBytesWritten()
*/
bool QIODevice::waitForReadyRead(int msecs)
{
    Q_UNUSED(msecs);
    return false;
}

/*!
    For buffered devices, this function waits until a payload of
    buffered written data has been written to the device and the
    bytesWritten() signal has been emitted, or until \a msecs
    milliseconds have passed. If msecs is -1, this function will
    not time out. For unbuffered devices, it returns immediately.

    Returns true if a payload of data was written to the device;
    otherwise returns false (i.e. if the operation timed out, or if an
    error occurred).

    This function can operate without an event loop. It is
    useful when writing non-GUI applications and when performing
    I/O operations in a non-GUI thread.

    If called from within a slot connected to the bytesWritten() signal,
    bytesWritten() will not be reemitted.

    \warning Calling this function from the main (GUI) thread
    might cause your user interface to freeze.

    \sa waitForReadyRead()
*/
bool QIODevice::waitForBytesWritten(int msecs)
{
    Q_UNUSED(msecs);
    return false;
}

/*!
    Sets the human readable description of the last device error that
    occurred to \a str.

    \sa errorString()
*/
void QIODevice::setErrorString(const QString &str)
{
    d_func()->errorString = str;
}

/*!
    Returns a human-readable description of the last device error that
    occurred.

    \sa setErrorString()
*/
QString QIODevice::errorString() const
{
    return d_func()->errorString;
}

/*!
    \fn qint64 QIODevice::readData(char *data, qint64 maxSize)

    Reads up to \a maxSize bytes from the device into \a data, and
    returns the number of bytes read or -1 if an error occurred.

    This function is called by QIODevice. Reimplement this function
    when creating a subclass of QIODevice.

    \sa read() readLine() writeData()
*/

/*!
    \fn qint64 QIODevice::writeData(const char *data, qint64 maxSize)

    Writes up to \a maxSize bytes from \a data to the device. Returns
    the number of bytes written, or -1 if an error occurred.

    This function is called by QIODevice. Reimplement this function
    when creating a subclass of QIODevice.

    \sa read() write()
*/

/*!
    \fn QIODevice::Offset QIODevice::status() const

    For device specific error handling, please refer to the
    individual device documentation.

    \sa qobject_cast()
*/

/*!
    \fn QIODevice::Offset QIODevice::at() const

    Use pos() instead.
*/

/*!
    \fn bool QIODevice::at(Offset offset)

    Use seek(\a offset) instead.
*/

/*! \fn int QIODevice::flags() const

    Use openMode() instead.
*/

/*! \fn int QIODevice::getch()

    Use getChar() instead.
*/

/*!
    \fn bool QIODevice::isAsynchronous() const

    This functionality is no longer available. This function always
    returns true.
*/

/*!
    \fn bool QIODevice::isBuffered() const

    Use !(openMode() & QIODevice::Unbuffered) instead.
*/

/*!
    \fn bool QIODevice::isCombinedAccess() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::isDirectAccess() const

    Use !isSequential() instead.
*/

/*!
    \fn bool QIODevice::isInactive() const

    Use isOpen(), isReadable(), or isWritable() instead.
*/

/*!
    \fn bool QIODevice::isRaw() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::isSequentialAccess() const

    Use isSequential() instead.
*/

/*!
    \fn bool QIODevice::isSynchronous() const

    This functionality is no longer available. This function always
    returns false.
*/

/*!
    \fn bool QIODevice::isTranslated() const

    Use openMode() instead.
*/

/*!
    \fn bool QIODevice::mode() const

    Use openMode() instead.
*/

/*! \fn int QIODevice::putch(int ch)

    Use putChar(\a ch) instead.
*/

/*! \fn int QIODevice::ungetch(int ch)

    Use ungetChar(\a ch) instead.
*/

/*!
    \fn quint64 QIODevice::readBlock(char *data, quint64 size)

    Use read(\a data, \a size) instead.
*/

/*! \fn int QIODevice::state() const

    Use isOpen() instead.
*/

/*!
    \fn qint64 QIODevice::writeBlock(const char *data, quint64 size)

    Use write(\a data, \a size) instead.
*/

/*!
    \fn qint64 QIODevice::writeBlock(const QByteArray &data)

    Use write(\a data) instead.
*/

#if defined QT3_SUPPORT
QIODevice::Status QIODevice::status() const
{
#if !defined(QT_NO_QOBJECT)
    const QFile *f = qobject_cast<const QFile *>(this);
    if (f) return (int) f->error();
#endif
    return isOpen() ? 0 /* IO_Ok */ : 8 /* IO_UnspecifiedError */;
}

/*!
    For device specific error handling, please refer to the
    individual device documentation.

    \sa qobject_cast()
*/
void QIODevice::resetStatus()
{
#if !defined(QT_NO_QOBJECT)
    QFile *f = qobject_cast<QFile *>(this);
    if (f) f->unsetError();
#endif
}
#endif

#if !defined(QT_NO_DEBUG_STREAM)
QDebug operator<<(QDebug debug, QIODevice::OpenMode modes)
{
    debug << "OpenMode(";
    QStringList modeList;
    if (modes == QIODevice::NotOpen) {
        modeList << "NotOpen";
    } else {
        if (modes & QIODevice::ReadOnly)
            modeList << "ReadOnly";
        if (modes & QIODevice::WriteOnly)
            modeList << "WriteOnly";
        if (modes & QIODevice::Append)
            modeList << "Append";
        if (modes & QIODevice::Truncate)
            modeList << "Truncate";
        if (modes & QIODevice::Text)
            modeList << "Text";
        if (modes & QIODevice::Unbuffered)
            modeList << "Unbuffered";
    }
    qSort(modeList);
    debug << modeList.join("|");
    debug << ")";
    return debug;
}
#endif