update-client/MainApp/MainWindow.cpp

#include "MainWindow.h"
#include <QApplication>
#include <QFont>
#include <QFile>
#include <QLabel>
#include <QVBoxLayout>
#include <QCryptographicHash>
#include "../Common/PolicyHelper.h"
#include "../Common/ConfigHelper.h"

static QString readDllVersion(const QString& dllPath)
{
    QFile file(dllPath);
    if (!file.exists())
        return QCoreApplication::translate("MainWindow", "missing");

    if (!file.open(QIODevice::ReadOnly))
        return QCoreApplication::translate("MainWindow", "unreadable");

    QByteArray data = file.read(1024);
    file.close();
    return QString::fromUtf8(QCryptographicHash::hash(data, QCryptographicHash::Sha256).toHex().left(8));
}

MainWindow::MainWindow(QWidget* parent)
    : QWidget(parent)
{
    this->setWindowTitle(tr("Marsco Demo MainApp"));
    this->resize(600, 400);

    QString appVersion = ConfigHelper::instance().getValue("App", "current_version");
    if (appVersion.isEmpty())
        appVersion = tr("unknown");

    QString dllVersion = readDllVersion(QApplication::applicationDirPath() + "/plugins/demo_plugin.dll");

    PolicyHelper policy(QApplication::applicationDirPath());
    QString policyResult;
    if (!policy.loadPolicy("config/version_policy.dat"))
    {
        policyResult = tr("policy missing");
    }
    else if (!policy.isValid())
    {
        policyResult = tr("policy invalid");
    }
    else if (!policy.isVersionAllowed(appVersion))
    {
        policyResult = tr("version disabled");
    }
    else if (policy.isExpired())
    {
        policyResult = tr("policy expired");
    }
    else
    {
        policyResult = tr("policy ok");
    }

    QVBoxLayout* layout = new QVBoxLayout(this);
    QLabel* label = new QLabel(tr("Software Running Successfully\nVersion: %1\nDLL Version: %2\nPolicy: %3")
        .arg(appVersion)
        .arg(dllVersion)
        .arg(policyResult));
    QFont font = label->font();
    font.setPointSize(14);
    label->setFont(font);
    label->setAlignment(Qt::AlignCenter);

    layout->addWidget(label);
    this->setLayout(layout);
}