utun2/tools/chatgui/transport/config_updater.cpp

// config_updater.cpp — Universal INI config file updater
#include "config_updater.h"
#include <QFile>
#include <QTextStream>

bool config_update_option(const QString& filePath, const QString& section,
                           const QString& param, const QString& value, int flags)
{
    QStringList lines;

    QFile f(filePath);
    if (f.exists()) {
        if (!f.open(QIODevice::ReadOnly | QIODevice::Text))
            return false;
        QTextStream in(&f);
        while (!in.atEnd())
            lines.append(in.readLine());
        f.close();
    }

    const QString sectionHdr = "[" + section + "]";
    const QString newLine = param + "=" + value;

    int secIdx = -1;
    for (int i = 0; i < lines.size(); i++) {
        if (lines[i].trimmed() == sectionHdr) { secIdx = i; break; }
    }

    int secEnd = lines.size();
    if (secIdx >= 0) {
        for (int i = secIdx + 1; i < lines.size(); i++) {
            if (lines[i].trimmed().startsWith('[')) { secEnd = i; break; }
        }
    }

    if (secIdx >= 0) {
        int ins = secEnd;
        while (ins > secIdx + 1 && lines[ins - 1].trimmed().isEmpty())
            ins--;

        if (flags == CONFIG_UPDATE_REPLACE) {
            int paramIdx = -1;
            for (int i = secIdx + 1; i < secEnd; i++) {
                if (lines[i].trimmed().startsWith(param + "=")) { paramIdx = i; break; }
            }
            if (paramIdx >= 0)
                lines[paramIdx] = newLine;
            else
                lines.insert(ins, newLine);
        } else {
            lines.insert(ins, newLine);
        }
    } else {
        if (!lines.isEmpty() && !lines.last().trimmed().isEmpty())
            lines.append("");
        lines.append(sectionHdr);
        lines.append(newLine);
    }

    if (!f.open(QIODevice::WriteOnly | QIODevice::Text))
        return false;
    QTextStream out(&f);
    for (const QString& line : lines)
        out << line << "\n";
    f.close();
    return true;
}