translation_loader.hpp

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#ifndef TRANSLATION_LOADER_HPP
#define TRANSLATION_LOADER_HPP
 
/**
 * \file translation_loader.hpp
 * \brief Helper class for loading application and Qt translations.
 * \author Le Bars, Yoann
 * \ingroup UtilsTranslation
 *
 * This file is part of the pure C++ benchmark.
 */
 
#include <QApplication>
#include <QDebug>
#include <QLibraryInfo>
#include <QLocale>
#include <QString>
#include <QTranslator>
 
/// \brief Namespace for application-wide utility functions.
namespace AppUtils {
 
    /**
     * \brief Provides a static method to load translation files for the
     * application.
     * \ingroup UtilsTranslation
     */
    class TranslationLoader {
       public:
        /**
         * \brief Loads and installs the best-matching translation for the
         *        system’s locale.
         *
         * \param in_diagnosticsEnabled If true, prints detailed debug
         * information during loading.
         */
        static void loadTranslations(bool in_diagnosticsEnabled) {
            /* Helper lambdas to avoid repeated if(in_diagnosticsEnabled)
               checks. */
            const auto logInfo = [in_diagnosticsEnabled](const auto&... args) {
                if (in_diagnosticsEnabled) (qDebug().noquote() << ... << args);
            };
            // Lambda for logging successful operations.
            const auto logSuccess =
                [in_diagnosticsEnabled](const auto&... args) {
                    if (in_diagnosticsEnabled) (qDebug() << ... << args);
                };
            // Lambda for logging warnings.
            const auto logWarning =
                [in_diagnosticsEnabled](const auto&... args) {
                    if (in_diagnosticsEnabled)
                        (qWarning().noquote() << ... << args);
                };
 
            const QStringList uiLanguages = QLocale::system().uiLanguages();
            logSuccess("--- Translation Debug ---");
            logSuccess("System UI Languages:", uiLanguages);
 
            for (const QString& locale : uiLanguages) {
                logInfo("Attempting to load locale:", locale);
                const QLocale qLocale(locale);
 
                // Load application's translator.
                const QString appTranslationPath = QLatin1String(":/i18n");
                // The translator is parented to qApp, so its lifetime is
                // managed by Qt.
                auto appTranslator = new QTranslator(qApp);
                logInfo("  - App translator: loading 'pure-cpp_", locale,
                        "' from", appTranslationPath);
                if (appTranslator->load(qLocale, QLatin1String("pure-cpp"),
                                        QLatin1String("_"),
                                        appTranslationPath)) {
                    logSuccess(
                        "    -> Success: Application translator installed.");
                    QApplication::installTranslator(appTranslator);
 
                    // Load Qt's base translator for the same locale.
                    auto qtTranslator = new QTranslator(qApp);
                    const QString qtTranslationPath =
                        QLibraryInfo::path(QLibraryInfo::TranslationsPath);
                    logInfo("  - Qt translator: loading 'qt_", locale, "' from",
                            qtTranslationPath);
                    if (qtTranslator->load(qLocale, QLatin1String("qt"),
                                           QLatin1String("_"),
                                           qtTranslationPath)) {
                        logSuccess(
                            "    -> Success: Qt base translator installed.");
                        QApplication::installTranslator(qtTranslator);
                    } else {
                        logWarning(
                            "    -> Failed: Could not load Qt base "
                            "translator.");
                    }
                    return;  // Stop after the first successful load.
                } else {
                    logWarning(
                        "  - App translator: Failed to load translation for",
                        locale);
                    // Clean up if load failed before next iteration.
                    delete appTranslator;
                }
            }
        }
    };
 
}  // namespace AppUtils
 
#endif  // TRANSLATION_LOADER_HPP