qcoloroutput.cpp

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#include <QFile>
#include <QHash>
#include <QTextCodec>

#include "qcoloroutput_p.h"

// TODO: rename insertMapping() to insertColorMapping()
// TODO: Use a smart pointer for managing ColorOutputPrivate *d;
// TODO: break out the C++ example into a snippet file

/* This include must appear here, because if it appears at the beginning of the file for
 * instance, it breaks build -- "qglobal.h:628: error: template with
 * C linkage" -- on Mac OS X 10.4. */
#ifndef Q_OS_WIN
#include <unistd.h>
#endif

QT_BEGIN_NAMESPACE

using namespace QPatternist;

namespace QPatternist
{
    class ColorOutputPrivate
    {
    public:
        ColorOutputPrivate() : currentColorID(-1)

        {
            /* - QIODevice::Unbuffered because we want it to appear when the user actually calls, performance
             *   is considered of lower priority.
             */
            m_out.open(stderr, QIODevice::WriteOnly | QIODevice::Unbuffered);

            coloringEnabled = isColoringPossible();
        }

        ColorOutput::ColorMapping   colorMapping;
        int                         currentColorID;
        bool                        coloringEnabled;

        static const char *const foregrounds[];
        static const char *const backgrounds[];

        inline void write(const QString &msg)
        {
            m_out.write(msg.toLocal8Bit());
        }

        static QString escapeCode(const QString &in)
        {
            QString result;
            result.append(QChar(0x1B));
            result.append(QLatin1Char('['));
            result.append(in);
            result.append(QLatin1Char('m'));
            return result;
        }

    private:
        QFile                       m_out;

        inline bool isColoringPossible() const
        {
#           if defined(Q_OS_WIN32) || defined(Q_OS_WINCE)
                /* Windows doesn't at all support ANSI escape codes, unless
                 * the user install a "device driver". See the Wikipedia links in the
                 * class documentation for details. */
                return false;
#           else
                /* We use QFile::handle() to get the file descriptor. It's a bit unsure
                 * whether it's 2 on all platforms and in all cases, so hopefully this layer
                 * of abstraction helps handle such cases. */
                return isatty(m_out.handle());
#           endif
        }
    };
}

const char *const ColorOutputPrivate::foregrounds[] =
{
    "0;30",
    "0;34",
    "0;32",
    "0;36",
    "0;31",
    "0;35",
    "0;33",
    "0;37",
    "1;30",
    "1;34",
    "1;32",
    "1;36",
    "1;31",
    "1;35",
    "1;33",
    "1;37"
};

const char *const ColorOutputPrivate::backgrounds[] =
{
    "0;40",
    "0;44",
    "0;42",
    "0;46",
    "0;41",
    "0;45",
    "0;43"
};

void ColorOutput::setColorMapping(const ColorMapping &cMapping)
{
    d->colorMapping = cMapping;
}

ColorOutput::ColorMapping ColorOutput::colorMapping() const
{
    return d->colorMapping;
}

ColorOutput::ColorOutput() : d(new ColorOutputPrivate())
{
}

ColorOutput::~ColorOutput()
{
    delete d;
}

void ColorOutput::write(const QString &message, int colorID)
{
    d->write(colorify(message, colorID));
}

void ColorOutput::writeUncolored(const QString &message)
{
    d->write(message + QLatin1Char('\n'));
}

QString ColorOutput::colorify(const QString &message, int colorID) const
{
    Q_ASSERT_X(colorID == -1 || d->colorMapping.contains(colorID), Q_FUNC_INFO,
               qPrintable(QString::fromLatin1("There is no color registered by id %1").arg(colorID)));
    Q_ASSERT_X(!message.isEmpty(), Q_FUNC_INFO, "It makes no sense to attempt to print an empty string.");

    if(colorID != -1)
        d->currentColorID = colorID;

    if(d->coloringEnabled && colorID != -1)
    {
        const int color(d->colorMapping.value(colorID));

        /* If DefaultColor is set, we don't want to color it. */
        if(color & DefaultColor)
            return message;

        const int foregroundCode = (int(color) & ForegroundMask) >> ForegroundShift;
        const int backgroundCode = (int(color) & BackgroundMask) >> BackgroundShift;
        QString finalMessage;
        bool closureNeeded = false;

        if(foregroundCode)
        {
            finalMessage.append(ColorOutputPrivate::escapeCode(QLatin1String(ColorOutputPrivate::foregrounds[foregroundCode - 1])));
            closureNeeded = true;
        }

        if(backgroundCode)
        {
            finalMessage.append(ColorOutputPrivate::escapeCode(QLatin1String(ColorOutputPrivate::backgrounds[backgroundCode - 1])));
            closureNeeded = true;
        }

        finalMessage.append(message);

        if(closureNeeded)
        {
            finalMessage.append(QChar(0x1B));
            finalMessage.append(QLatin1String("[0m"));
        }

        return finalMessage;
    }
    else
        return message;
}

void ColorOutput::insertMapping(int colorID, const ColorCode colorCode)
{
    d->colorMapping.insert(colorID, colorCode);
}

QT_END_NAMESPACE