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** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
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#include "qdebugmessageservice_p.h"
#include "qqmldebugservice_p_p.h"

#include <QDataStream>
#include <QMutex>

QT_BEGIN_NAMESPACE

Q_GLOBAL_STATIC(QDebugMessageService, qmlDebugMessageService)

void DebugMessageHandler(QtMsgType type, const QMessageLogContext &ctxt,
                         const QString &buf)
{
    QDebugMessageService::instance()->sendDebugMessage(type, ctxt, buf);
}

class QDebugMessageServicePrivate : public QQmlDebugServicePrivate
{
public:
    QDebugMessageServicePrivate()
        : oldMsgHandler(0)
        , prevState(QQmlDebugService::NotConnected)
    {
    }

    QtMessageHandler oldMsgHandler;
    QQmlDebugService::State prevState;
    QMutex initMutex;
};

QDebugMessageService::QDebugMessageService(QObject *parent) :
    QQmlDebugService(*(new QDebugMessageServicePrivate()),
                                   QStringLiteral("DebugMessages"), 2, parent)
{
    Q_D(QDebugMessageService);

    // don't execute stateChanged() in parallel
    QMutexLocker lock(&d->initMutex);
    registerService();
    if (state() == Enabled) {
        d->oldMsgHandler = qInstallMessageHandler(DebugMessageHandler);
        d->prevState = Enabled;
    }
}

QDebugMessageService *QDebugMessageService::instance()
{
    return qmlDebugMessageService();
}

void QDebugMessageService::sendDebugMessage(QtMsgType type,
                                            const QMessageLogContext &ctxt,
                                            const QString &buf)
{
    Q_D(QDebugMessageService);

    //We do not want to alter the message handling mechanism
    //We just eavesdrop and forward the messages to a port
    //only if a client is connected to it.
    QByteArray message;
    QQmlDebugStream ws(&message, QIODevice::WriteOnly);
    ws << QByteArray("MESSAGE") << type << buf.toUtf8();
    ws << QString::fromLatin1(ctxt.file).toUtf8();
    ws << ctxt.line << QString::fromLatin1(ctxt.function).toUtf8();

    sendMessage(message);
    if (d->oldMsgHandler)
        (*d->oldMsgHandler)(type, ctxt, buf);
}

void QDebugMessageService::stateChanged(State state)
{
    Q_D(QDebugMessageService);
    QMutexLocker lock(&d->initMutex);

    if (state != Enabled && d->prevState == Enabled) {
        QtMessageHandler handler = qInstallMessageHandler(d->oldMsgHandler);
        // has our handler been overwritten in between?
        if (handler != DebugMessageHandler)
            qInstallMessageHandler(handler);

    } else if (state == Enabled && d->prevState != Enabled) {
        d->oldMsgHandler = qInstallMessageHandler(DebugMessageHandler);
    }

    d->prevState = state;
}

QT_END_NAMESPACE