gQtTranslation.cc

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#include "gQtTranslation.h"
 
#include <gemc/glogging/gmessageCatalog.h>
#include <QLibraryInfo>
#include <QLocale>
#include <QTranslator>
#include <QVariant>
 
#include <vector>
 
// Q_INIT_RESOURCE must resolve the generated resource symbol in the global namespace.
static void initializeGuiResources() { Q_INIT_RESOURCE(gemc_gui_translations); }
 
void gemc::installGuiTranslations(QCoreApplication& application, const GOptions* options) {
    initializeGuiResources();
    const auto language = GMessageCatalog::load(options)->language();
    if (auto* previous = application.findChild<QObject*>("gemcGuiTranslators", Qt::FindDirectChildrenOnly)) {
        delete previous; // QTranslator unregisters itself when destroyed.
    }
    auto* owner = new QObject(&application);
    owner->setObjectName("gemcGuiTranslators");
    application.setProperty("gemcGuiLanguage", QString::fromStdString(language));
    if (language == "en" || language.starts_with("en-")) return;
 
    auto* standard = new QTranslator(owner);
    const auto locale = QLocale(QString::fromStdString(language).replace('-', '_'));
    if (standard->load(locale, "qtbase", "_", QLibraryInfo::path(QLibraryInfo::TranslationsPath))) {
        application.installTranslator(standard);
    }
 
    const auto separator = language.find('-');
    const auto base = language.substr(0, separator);
    auto* embedded = new QTranslator(owner);
    if (embedded->load(QString::fromStdString(":/gemc/gui/" + base + ".qm"))) {
        application.installTranslator(embedded);
    }
 
    std::vector<std::string> variants{base};
    if (base != language) variants.push_back(language);
    const auto directories = GMessageCatalog::searchDirectories(options);
    for (const auto& variant : variants) {
        // Install low-priority files first: Qt checks the most recently installed translator first.
        for (auto directory = directories.rbegin(); directory != directories.rend(); ++directory) {
            for (const auto& path : {*directory / "gui" / (variant + ".qm"), *directory / (variant + ".qm")}) {
                std::error_code error;
                if (!std::filesystem::is_regular_file(path, error)) continue;
                auto* translator = new QTranslator(owner);
                if (translator->load(QString::fromStdString(path.string()))) {
                    application.installTranslator(translator);
                } else {
                    qWarning("Ignoring invalid GUI translation catalog: %s", path.string().c_str());
                    delete translator;
                }
            }
        }
    }
}