jamulus/src/settings.cpp

/******************************************************************************\
 * Copyright (c) 2004-2020
 *
 * Author(s):
 *  Volker Fischer
 *
 ******************************************************************************
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later 
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
\******************************************************************************/

#include "settings.h"


/* Implementation *************************************************************/
void CSettings::Load()
{
    int          iIdx;
    int          iValue;
    bool         bValue;
    QDomDocument IniXMLDocument;

    // prepare file name for loading initialization data from XML file and read
    // data from file if possible
    QFile file ( strFileName );
    if ( file.open ( QIODevice::ReadOnly ) )
    {
        QTextStream in ( &file );
        IniXMLDocument.setContent ( in.readAll(), false );

        file.close();
    }


    // Actual settings data ---------------------------------------------------
    if ( bIsClient )
    {
        // client:

        // IP addresses
        for ( iIdx = 0; iIdx < MAX_NUM_SERVER_ADDR_ITEMS; iIdx++ )
        {
            pClient->vstrIPAddress[iIdx] =
                GetIniSetting ( IniXMLDocument, "client",
                                QString ( "ipaddress%1" ).arg ( iIdx ), "" );
        }

        // stored fader tags
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            pClient->vecStoredFaderTags[iIdx] = FromBase64ToString (
                GetIniSetting ( IniXMLDocument, "client",
                                QString ( "storedfadertag%1_base64" ).arg ( iIdx ), "" ) );
        }

        // stored fader levels
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            if ( GetNumericIniSet ( IniXMLDocument, "client",
                                    QString ( "storedfaderlevel%1" ).arg ( iIdx ),
                                    0, AUD_MIX_FADER_MAX, iValue ) )
            {
                pClient->vecStoredFaderLevels[iIdx] = iValue;
            }
        }

        // stored fader solo state
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            if ( GetFlagIniSet ( IniXMLDocument, "client",
                                 QString ( "storedfaderissolo%1" ).arg ( iIdx ),
                                 bValue ) )
            {
                pClient->vecStoredFaderIsSolo[iIdx] = bValue;
            }
        }

        // new client level
        if ( GetNumericIniSet ( IniXMLDocument, "client", "newclientlevel",
             0, 100, iValue ) )
        {
            pClient->iNewClientFaderLevel = iValue;
        }

        // name
        pClient->ChannelInfo.strName = FromBase64ToString (
            GetIniSetting ( IniXMLDocument, "client", "name_base64" ) );

        // instrument
        if ( GetNumericIniSet ( IniXMLDocument, "client", "instrument",
             0, CInstPictures::GetNumAvailableInst() - 1, iValue ) )
        {
            pClient->ChannelInfo.iInstrument = iValue;
        }

        // country
        if ( GetNumericIniSet ( IniXMLDocument, "client", "country",
             0, static_cast<int> ( QLocale::LastCountry ), iValue ) )
        {
            pClient->ChannelInfo.eCountry = static_cast<QLocale::Country> ( iValue );
        }
        else
        {
            // if no country is given, use the one from the operating system
            pClient->ChannelInfo.eCountry = QLocale::system().country();
        }

        // city
        pClient->ChannelInfo.strCity = FromBase64ToString (
            GetIniSetting ( IniXMLDocument, "client", "city_base64" ) );

        // skill level
        if ( GetNumericIniSet ( IniXMLDocument, "client", "skill",
             0, 3 /* SL_PROFESSIONAL */, iValue ) )
        {
            pClient->ChannelInfo.eSkillLevel = static_cast<ESkillLevel> ( iValue );
        }

        // audio fader
        if ( GetNumericIniSet ( IniXMLDocument, "client", "audfad",
             AUD_FADER_IN_MIN, AUD_FADER_IN_MAX, iValue ) )
        {
            pClient->SetAudioInFader ( iValue );
        }

        // reverberation level
        if ( GetNumericIniSet ( IniXMLDocument, "client", "revlev",
             0, AUD_REVERB_MAX, iValue ) )
        {
            pClient->SetReverbLevel ( iValue );
        }

        // reverberation channel assignment
        if ( GetFlagIniSet ( IniXMLDocument, "client", "reverblchan", bValue ) )
        {
            pClient->SetReverbOnLeftChan ( bValue );
        }

        // sound card selection
        // special case with this setting: the sound card initialization depends
        // on this setting call, therefore, if no setting file parameter could
        // be retrieved, the sound card is initialized with a default setting
        // defined here
        if ( GetNumericIniSet ( IniXMLDocument, "client", "auddevidx",
             1, MAX_NUMBER_SOUND_CARDS, iValue ) )
        {
            pClient->SetSndCrdDev ( iValue );
        }
        else
        {
            // use "INVALID_SNC_CARD_DEVICE" to tell the sound card driver that
            // no device selection was done previously
            pClient->SetSndCrdDev ( INVALID_SNC_CARD_DEVICE );
        }

        // sound card channel mapping settings: make sure these settings are
        // set AFTER the sound card device is set, otherwise the settings are
        // overwritten by the defaults
        //
        // sound card left input channel mapping
        if ( GetNumericIniSet ( IniXMLDocument, "client", "sndcrdinlch",
             0, MAX_NUM_IN_OUT_CHANNELS - 1, iValue ) )
        {
            pClient->SetSndCrdLeftInputChannel ( iValue );
        }

        // sound card right input channel mapping
        if ( GetNumericIniSet ( IniXMLDocument, "client", "sndcrdinrch",
             0, MAX_NUM_IN_OUT_CHANNELS - 1, iValue ) )
        {
            pClient->SetSndCrdRightInputChannel ( iValue );
        }

        // sound card left output channel mapping
        if ( GetNumericIniSet ( IniXMLDocument, "client", "sndcrdoutlch",
             0, MAX_NUM_IN_OUT_CHANNELS - 1, iValue ) )
        {
            pClient->SetSndCrdLeftOutputChannel ( iValue );
        }

        // sound card right output channel mapping
        if ( GetNumericIniSet ( IniXMLDocument, "client", "sndcrdoutrch",
             0, MAX_NUM_IN_OUT_CHANNELS - 1, iValue ) )
        {
            pClient->SetSndCrdRightOutputChannel ( iValue );
        }

        // sound card preferred buffer size index
        if ( GetNumericIniSet ( IniXMLDocument, "client", "prefsndcrdbufidx",
             FRAME_SIZE_FACTOR_PREFERRED, FRAME_SIZE_FACTOR_SAFE, iValue ) )
        {
            // additional check required since only a subset of factors are
            // defined
            if ( ( iValue == FRAME_SIZE_FACTOR_PREFERRED ) ||
                 ( iValue == FRAME_SIZE_FACTOR_DEFAULT ) ||
                 ( iValue == FRAME_SIZE_FACTOR_SAFE ) )
            {
                pClient->SetSndCrdPrefFrameSizeFactor ( iValue );
            }
        }

        // automatic network jitter buffer size setting
        if ( GetFlagIniSet ( IniXMLDocument, "client", "autojitbuf", bValue ) )
        {
            pClient->SetDoAutoSockBufSize ( bValue );
        }

        // network jitter buffer size
        if ( GetNumericIniSet ( IniXMLDocument, "client", "jitbuf",
             MIN_NET_BUF_SIZE_NUM_BL, MAX_NET_BUF_SIZE_NUM_BL, iValue ) )
        {
            pClient->SetSockBufNumFrames ( iValue );
        }

        // network jitter buffer size for server
        if ( GetNumericIniSet ( IniXMLDocument, "client", "jitbufserver",
             MIN_NET_BUF_SIZE_NUM_BL, MAX_NET_BUF_SIZE_NUM_BL, iValue ) )
        {
            pClient->SetServerSockBufNumFrames ( iValue );
        }

        // GUI design
        if ( GetNumericIniSet ( IniXMLDocument, "client", "guidesign",
             0, 1 /* GD_ORIGINAL */, iValue ) )
        {
            pClient->SetGUIDesign ( static_cast<EGUIDesign> ( iValue ) );
        }

        // audio channels
        if ( GetNumericIniSet ( IniXMLDocument, "client", "audiochannels",
             0, 2 /* CC_STEREO */, iValue ) )
        {
            pClient->SetAudioChannels ( static_cast<EAudChanConf> ( iValue ) );
        }

        // audio quality
        if ( GetNumericIniSet ( IniXMLDocument, "client", "audioquality",
             0, 2 /* AQ_HIGH */, iValue ) )
        {
            pClient->SetAudioQuality ( static_cast<EAudioQuality> ( iValue ) );
        }

        // central server address
        pClient->SetServerListCentralServerAddress (
            GetIniSetting ( IniXMLDocument, "client", "centralservaddr" ) );

        // use default central server address flag
        if ( GetFlagIniSet ( IniXMLDocument, "client", "defcentservaddr", bValue ) )
        {
            pClient->SetUseDefaultCentralServerAddress ( bValue );
        }

        // window position of the main window
        pClient->vecWindowPosMain = FromBase64ToByteArray (
            GetIniSetting ( IniXMLDocument, "client", "winposmain_base64" ) );

        // window position of the settings window
        pClient->vecWindowPosSettings = FromBase64ToByteArray (
            GetIniSetting ( IniXMLDocument, "client", "winposset_base64" ) );

        // window position of the chat window
        pClient->vecWindowPosChat = FromBase64ToByteArray (
            GetIniSetting ( IniXMLDocument, "client", "winposchat_base64" ) );

        // window position of the musician profile window
        pClient->vecWindowPosProfile = FromBase64ToByteArray (
            GetIniSetting ( IniXMLDocument, "client", "winposprofile_base64" ) );

        // window position of the connect window
        pClient->vecWindowPosConnect = FromBase64ToByteArray (
            GetIniSetting ( IniXMLDocument, "client", "winposcon_base64" ) );

        // visibility state of the settings window
        if ( GetFlagIniSet ( IniXMLDocument, "client", "winvisset", bValue ) )
        {
            pClient->bWindowWasShownSettings = bValue;
        }

        // visibility state of the chat window
        if ( GetFlagIniSet ( IniXMLDocument, "client", "winvischat", bValue ) )
        {
            pClient->bWindowWasShownChat = bValue;
        }

        // visibility state of the musician profile window
        if ( GetFlagIniSet ( IniXMLDocument, "client", "winvisprofile", bValue ) )
        {
            pClient->bWindowWasShownProfile = bValue;
        }

        // visibility state of the connect window
        if ( GetFlagIniSet ( IniXMLDocument, "client", "winviscon", bValue ) )
        {
            pClient->bWindowWasShownConnect = bValue;
        }
    }
    else
    {
        // server:

        // use default central server address flag (note that it is important
        // to set this setting prior to the "central server address")
        if ( GetFlagIniSet ( IniXMLDocument, "server", "defcentservaddr", bValue ) )
        {
            pServer->SetUseDefaultCentralServerAddress ( bValue );
        }

        // central server address (to be set after the "use default central
        // server address)
        pServer->SetServerListCentralServerAddress (
            GetIniSetting ( IniXMLDocument, "server", "centralservaddr" ) );

        // server list enabled flag
        if ( GetFlagIniSet ( IniXMLDocument, "server", "servlistenabled", bValue ) )
        {
            pServer->SetServerListEnabled ( bValue );
        }

        // name
        pServer->SetServerName ( GetIniSetting ( IniXMLDocument, "server", "name" ) );

        // city
        pServer->SetServerCity ( GetIniSetting ( IniXMLDocument, "server", "city" ) );

        // country
        if ( GetNumericIniSet ( IniXMLDocument, "server", "country",
             0, static_cast<int> ( QLocale::LastCountry ), iValue ) )
        {
            pServer->SetServerCountry ( static_cast<QLocale::Country> ( iValue ) );
        }

        // start minimized on OS start
        if ( GetFlagIniSet ( IniXMLDocument, "server", "autostartmin", bValue ) )
        {
            pServer->SetAutoRunMinimized ( bValue );
        }
    }
}

void CSettings::Save()
{
    int iIdx;

    // create XML document for storing initialization parameters
    QDomDocument IniXMLDocument;


    // Actual settings data ---------------------------------------------------
    if ( bIsClient )
    {
        // client:

        // IP addresses
        for ( iIdx = 0; iIdx < MAX_NUM_SERVER_ADDR_ITEMS; iIdx++ )
        {
            PutIniSetting ( IniXMLDocument, "client",
                            QString ( "ipaddress%1" ).arg ( iIdx ),
                            pClient->vstrIPAddress[iIdx] );
        }

        // stored fader tags
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            PutIniSetting ( IniXMLDocument, "client",
                            QString ( "storedfadertag%1_base64" ).arg ( iIdx ),
                            ToBase64 ( pClient->vecStoredFaderTags[iIdx] ) );
        }

        // stored fader levels
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            SetNumericIniSet ( IniXMLDocument, "client",
                               QString ( "storedfaderlevel%1" ).arg ( iIdx ),
                               pClient->vecStoredFaderLevels[iIdx] );
        }

        // stored fader solo states
        for ( iIdx = 0; iIdx < MAX_NUM_STORED_FADER_SETTINGS; iIdx++ )
        {
            SetFlagIniSet ( IniXMLDocument, "client",
                            QString ( "storedfaderissolo%1" ).arg ( iIdx ),
                            pClient->vecStoredFaderIsSolo[iIdx] != false );
        }

        // new client level
        SetNumericIniSet ( IniXMLDocument, "client", "newclientlevel",
            pClient->iNewClientFaderLevel );

        // name
        PutIniSetting ( IniXMLDocument, "client", "name_base64",
            ToBase64 ( pClient->ChannelInfo.strName ) );

        // instrument
        SetNumericIniSet ( IniXMLDocument, "client", "instrument",
            pClient->ChannelInfo.iInstrument );

        // country
        SetNumericIniSet ( IniXMLDocument, "client", "country",
            static_cast<int> ( pClient->ChannelInfo.eCountry ) );

        // city
        PutIniSetting ( IniXMLDocument, "client", "city_base64",
            ToBase64 ( pClient->ChannelInfo.strCity ) );

        // skill level
        SetNumericIniSet ( IniXMLDocument, "client", "skill",
            static_cast<int> ( pClient->ChannelInfo.eSkillLevel ) );

        // audio fader
        SetNumericIniSet ( IniXMLDocument, "client", "audfad",
            pClient->GetAudioInFader() );

        // reverberation level
        SetNumericIniSet ( IniXMLDocument, "client", "revlev",
            pClient->GetReverbLevel() );

        // reverberation channel assignment
        SetFlagIniSet ( IniXMLDocument, "client", "reverblchan",
            pClient->IsReverbOnLeftChan() );

        // sound card selection
        SetNumericIniSet ( IniXMLDocument, "client", "auddevidx",
            pClient->GetSndCrdDev() );

        // sound card left input channel mapping
        SetNumericIniSet ( IniXMLDocument, "client", "sndcrdinlch",
            pClient->GetSndCrdLeftInputChannel() );

        // sound card right input channel mapping
        SetNumericIniSet ( IniXMLDocument, "client", "sndcrdinrch",
            pClient->GetSndCrdRightInputChannel() );

        // sound card left output channel mapping
        SetNumericIniSet ( IniXMLDocument, "client", "sndcrdoutlch",
            pClient->GetSndCrdLeftOutputChannel() );

        // sound card right output channel mapping
        SetNumericIniSet ( IniXMLDocument, "client", "sndcrdoutrch",
            pClient->GetSndCrdRightOutputChannel() );

        // sound card preferred buffer size index
        SetNumericIniSet ( IniXMLDocument, "client", "prefsndcrdbufidx",
            pClient->GetSndCrdPrefFrameSizeFactor() );

        // automatic network jitter buffer size setting
        SetFlagIniSet ( IniXMLDocument, "client", "autojitbuf",
            pClient->GetDoAutoSockBufSize() );

        // network jitter buffer size
        SetNumericIniSet ( IniXMLDocument, "client", "jitbuf",
            pClient->GetSockBufNumFrames() );

        // network jitter buffer size for server
        SetNumericIniSet ( IniXMLDocument, "client", "jitbufserver",
            pClient->GetServerSockBufNumFrames() );

        // GUI design
        SetNumericIniSet ( IniXMLDocument, "client", "guidesign",
            static_cast<int> ( pClient->GetGUIDesign() ) );

        // audio channels
        SetNumericIniSet ( IniXMLDocument, "client", "audiochannels",
            static_cast<int> ( pClient->GetAudioChannels() ) );

        // audio quality
        SetNumericIniSet ( IniXMLDocument, "client", "audioquality",
            static_cast<int> ( pClient->GetAudioQuality() ) );

        // central server address
        PutIniSetting ( IniXMLDocument, "client", "centralservaddr",
            pClient->GetServerListCentralServerAddress() );

        // use default central server address flag
        SetFlagIniSet ( IniXMLDocument, "client", "defcentservaddr",
            pClient->GetUseDefaultCentralServerAddress() );

        // window position of the main window
        PutIniSetting ( IniXMLDocument, "client", "winposmain_base64",
            ToBase64 ( pClient->vecWindowPosMain ) );

        // window position of the settings window
        PutIniSetting ( IniXMLDocument, "client", "winposset_base64",
            ToBase64 ( pClient->vecWindowPosSettings ) );

        // window position of the chat window
        PutIniSetting ( IniXMLDocument, "client", "winposchat_base64",
            ToBase64 ( pClient->vecWindowPosChat ) );

        // window position of the musician profile window
        PutIniSetting ( IniXMLDocument, "client", "winposprofile_base64",
            ToBase64 ( pClient->vecWindowPosProfile ) );

        // window position of the connect window
        PutIniSetting ( IniXMLDocument, "client", "winposcon_base64",
            ToBase64 ( pClient->vecWindowPosConnect ) );

        // visibility state of the settings window
        SetFlagIniSet ( IniXMLDocument, "client", "winvisset",
            pClient->bWindowWasShownSettings );

        // visibility state of the chat window
        SetFlagIniSet ( IniXMLDocument, "client", "winvischat",
            pClient->bWindowWasShownChat );

        // visibility state of the musician profile window
        SetFlagIniSet ( IniXMLDocument, "client", "winvisprofile",
            pClient->bWindowWasShownProfile );

        // visibility state of the connect window
        SetFlagIniSet ( IniXMLDocument, "client", "winviscon",
            pClient->bWindowWasShownConnect );
    }
    else
    {
        // server:

        // central server address
        PutIniSetting ( IniXMLDocument, "server", "centralservaddr",
            pServer->GetServerListCentralServerAddress() );

        // use default central server address flag
        SetFlagIniSet ( IniXMLDocument, "server", "defcentservaddr",
            pServer->GetUseDefaultCentralServerAddress() );

        // server list enabled flag
        SetFlagIniSet ( IniXMLDocument, "server", "servlistenabled",
            pServer->GetServerListEnabled() );

        // name
        PutIniSetting ( IniXMLDocument, "server", "name",
            pServer->GetServerName() );

        // city
        PutIniSetting ( IniXMLDocument, "server", "city",
            pServer->GetServerCity() );

        // country
        SetNumericIniSet ( IniXMLDocument, "server", "country",
            static_cast<int> ( pServer->GetServerCountry() ) );

        // start minimized on OS start
        SetFlagIniSet ( IniXMLDocument, "server", "autostartmin",
            pServer->GetAutoRunMinimized() );
    }

    // prepare file name for storing initialization data in XML file and store
    // XML data in file
    QFile file ( strFileName );
    if ( file.open ( QIODevice::WriteOnly ) )
    {
        QTextStream out ( &file );
        out << IniXMLDocument.toString();

        file.close();
    }
}


// Help functions **************************************************************
void CSettings::SetFileName ( const QString& sNFiName )
{
    // return the file name with complete path, take care if given file name is
    // empty
    strFileName = sNFiName;
    if ( strFileName.isEmpty() )
    {
        // we use the Qt default setting file paths for the different OSs by
        // utilizing the QSettings class
        const QSettings TempSettingsObject (
            QSettings::IniFormat, QSettings::UserScope, APP_NAME, APP_NAME );

        const QString sConfigDir =
            QFileInfo ( TempSettingsObject.fileName() ).absolutePath();

        // make sure the directory exists
        if ( !QFile::exists ( sConfigDir ) )
        {
            QDir TempDirectoryObject;
            TempDirectoryObject.mkpath ( sConfigDir );
        }

        // append the actual file name
        if ( bIsClient )
        {
            strFileName = sConfigDir + "/" + DEFAULT_INI_FILE_NAME;
        }
        else
        {
            strFileName = sConfigDir + "/" + DEFAULT_INI_FILE_NAME_SERVER;
        }
    }
}

void CSettings::SetNumericIniSet ( QDomDocument&  xmlFile,
                                   const QString& strSection,
                                   const QString& strKey,
                                   const int      iValue )
{
    // convert input parameter which is an integer to string and store
    PutIniSetting ( xmlFile, strSection, strKey, QString("%1").arg(iValue) );
}

bool CSettings::GetNumericIniSet ( const QDomDocument& xmlFile,
                                   const QString&      strSection,
                                   const QString&      strKey,
                                   const int           iRangeStart,
                                   const int           iRangeStop,
                                   int&                iValue )
{
    // init return value
    bool bReturn = false;

    const QString strGetIni = GetIniSetting ( xmlFile, strSection, strKey );

    // check if it is a valid parameter
    if ( !strGetIni.isEmpty() )
    {
        // convert string from init file to integer
        iValue = strGetIni.toInt();

        // check range
        if ( ( iValue >= iRangeStart ) && ( iValue <= iRangeStop ) )
        {
            bReturn = true;
        }
    }

    return bReturn;
}

void CSettings::SetFlagIniSet ( QDomDocument&  xmlFile,
                                const QString& strSection,
                                const QString& strKey,
                                const bool     bValue )
{
    // we encode true -> "1" and false -> "0"
    if ( bValue == true )
    {
        PutIniSetting ( xmlFile, strSection, strKey, "1" );
    }
    else
    {
        PutIniSetting ( xmlFile, strSection, strKey, "0" );
    }
}

bool CSettings::GetFlagIniSet ( const QDomDocument& xmlFile,
                                const QString&      strSection,
                                const QString&      strKey,
                                bool&               bValue )
{
    // init return value
    bool bReturn = false;

    const QString strGetIni = GetIniSetting ( xmlFile, strSection, strKey );

    if ( !strGetIni.isEmpty() )
    {
        if ( strGetIni.toInt() )
        {
            bValue = true;
        }
        else
        {
            bValue = false;
        }

        bReturn = true;
    }

    return bReturn;
}


// Init-file routines using XML ***********************************************
QString CSettings::GetIniSetting ( const QDomDocument& xmlFile,
                                   const QString&      sSection,
                                   const QString&      sKey,
                                   const QString&      sDefaultVal )
{
    // init return parameter with default value
    QString sResult ( sDefaultVal );

    // get section
    QDomElement xmlSection = xmlFile.firstChildElement ( sSection );
    if ( !xmlSection.isNull() )
    {
        // get key
        QDomElement xmlKey = xmlSection.firstChildElement ( sKey );
        if ( !xmlKey.isNull() )
        {
            // get value
            sResult = xmlKey.text();
        }
    }

    return sResult;
}

void CSettings::PutIniSetting ( QDomDocument&  xmlFile,
                                const QString& sSection,
                                const QString& sKey,
                                const QString& sValue )
{
    // check if section is already there, if not then create it
    QDomElement xmlSection = xmlFile.firstChildElement ( sSection );
    if ( xmlSection.isNull() )
    {
        // create new root element and add to document
        xmlSection = xmlFile.createElement ( sSection );
        xmlFile.appendChild ( xmlSection );
    }

    // check if key is already there, if not then create it
    QDomElement xmlKey = xmlSection.firstChildElement ( sKey );
    if ( xmlKey.isNull() )
    {
        xmlKey = xmlFile.createElement ( sKey );
        xmlSection.appendChild ( xmlKey );
    }

    // add actual data to the key
    QDomText currentValue = xmlFile.createTextNode ( sValue );
    xmlKey.appendChild ( currentValue );
}