1 files changed, 88 insertions, 0 deletions
diff --git a/tests/shared/localechange.h b/tests/shared/localechange.h
new file mode 100644
index 0000000000..74ed444ba6
--- /dev/null
+++ b/tests/shared/localechange.h
@@ -0,0 +1,88 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+#ifndef QT_TESTS_SHARED_LOCALE_CHANGE_H
+#define QT_TESTS_SHARED_LOCALE_CHANGE_H
+#include <qglobal.h>
+#include <QtCore/QByteArray>
+#include <QtCore/QLocale>
+#include <private/qlocale_p.h>
+
+#include <locale.h>
+
+namespace QTestLocaleChange {
+
+    inline QLocale resetSystemLocale()
+    {
+#ifndef QT_NO_SYSTEMLOCALE
+        { // Transient instance marks system locale data as stale:
+            QSystemLocale dummy;
+        } // Now we can reinitialize:
+#endif
+        return QLocale::system();
+    }
+
+    class TransientLocale
+    {
+        const int m_category;
+        const QByteArray m_prior;
+        const bool m_didSet;
+#if !defined(QT_NO_SYSTEMLOCALE) && defined(Q_OS_UNIX) && !defined(Q_OS_DARWIN)
+#define TRANSIENT_ENV
+        // Unix system locale consults environment variables, so we need to set
+        // the appropriate one, too.
+        const QByteArray m_envVar, m_envPrior;
+        const bool m_envSet;
+        static QByteArray categoryToEnv(int category)
+        {
+            switch (category) {
+#define CASE(cat) case cat: return #cat
+            CASE(LC_ALL); CASE(LC_NUMERIC); CASE(LC_TIME); CASE(LC_MONETARY);
+            CASE(LC_MESSAGES); CASE(LC_COLLATE);
+#ifdef LC_MEASUREMENT
+            CASE(LC_MEASUREMENT);
+#endif
+#undef CASE
+            // Nothing in our code pays attention to any other LC_*
+            default:
+                Q_UNREACHABLE();
+                qFatal("You need to add a case for this category");
+            }
+        }
+#endif // TRANSIENT_ENV
+    public:
+        TransientLocale(int category, const char *locale)
+            : m_category(category),
+              m_prior(setlocale(category, nullptr)),
+              // That return value may be stomped by this later call, so we copy
+              // it to a QByteArray for safe keeping.
+              m_didSet(setlocale(category, locale) != nullptr)
+#ifdef TRANSIENT_ENV
+            , m_envVar(categoryToEnv(category)),
+              m_envPrior(qgetenv(m_envVar.constData())),
+              m_envSet(qputenv(m_envVar.constData(), locale))
+#endif
+        {
+            resetSystemLocale();
+        }
+        ~TransientLocale()
+        {
+#ifdef TRANSIENT_ENV
+            if (m_envSet) {
+                if (m_envPrior.isEmpty())
+                    qunsetenv(m_envVar.constData());
+                else
+                    qputenv(m_envVar.constData(), m_envPrior);
+            }
+#endif
+            if (m_prior.size())
+                setlocale(m_category, m_prior.constData());
+            resetSystemLocale();
+        }
+#undef TRANSIENT_ENV
+
+        bool isValid() const { return m_didSet; }
+    };
+}
+
+#endif // QT_TESTS_SHARED_LOCALE_CHANGE_H