1 files changed, 126 insertions, 0 deletions
diff --git a/src/corelib/time/qtimezonelocale.cpp b/src/corelib/time/qtimezonelocale.cpp
new file mode 100644
index 0000000000..cf3a84b317
--- /dev/null
+++ b/src/corelib/time/qtimezonelocale.cpp
@@ -0,0 +1,126 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include <private/qtimezonelocale_p.h>
+#include <private/qtimezoneprivate_p.h>
+
+#if !QT_CONFIG(icu)
+#  include <private/qdatetime_p.h>
+// Use data generated from CLDR:
+#  include <private/qtimezonelocale_data_p.h>
+#  include <private/qtimezoneprivate_data_p.h>
+#endif
+
+QT_BEGIN_NAMESPACE
+
+#if QT_CONFIG(icu) // Get data from ICU:
+namespace {
+
+// Convert TimeType and NameType into ICU UCalendarDisplayNameType
+constexpr UCalendarDisplayNameType ucalDisplayNameType(QTimeZone::TimeType timeType,
+                                                       QTimeZone::NameType nameType)
+{
+    // TODO ICU C UCalendarDisplayNameType does not support full set of C++ TimeZone::EDisplayType
+    // For now, treat Generic as Standard
+    switch (nameType) {
+    case QTimeZone::OffsetName:
+        Q_UNREACHABLE(); // Callers of ucalTimeZoneDisplayName() should take care of OffsetName.
+    case QTimeZone::ShortName:
+        return timeType == QTimeZone::DaylightTime ? UCAL_SHORT_DST : UCAL_SHORT_STANDARD;
+    case QTimeZone::DefaultName:
+    case QTimeZone::LongName:
+        return timeType == QTimeZone::DaylightTime ? UCAL_DST : UCAL_STANDARD;
+    }
+    Q_UNREACHABLE_RETURN(UCAL_STANDARD);
+}
+
+} // nameless namespace
+
+namespace QtTimeZoneLocale {
+
+// Qt wrapper around ucal_getTimeZoneDisplayName()
+// Used directly by ICU backend; indirectly by TZ (see below).
+QString ucalTimeZoneDisplayName(UCalendar *ucal,
+                                QTimeZone::TimeType timeType,
+                                QTimeZone::NameType nameType,
+                                const QByteArray &localeCode)
+{
+    constexpr int32_t BigNameLength = 50;
+    int32_t size = BigNameLength;
+    QString result(size, Qt::Uninitialized);
+    auto dst = [&result]() { return reinterpret_cast<UChar *>(result.data()); };
+    UErrorCode status = U_ZERO_ERROR;
+    const UCalendarDisplayNameType utype = ucalDisplayNameType(timeType, nameType);
+
+    // size = ucal_getTimeZoneDisplayName(cal, type, locale, result, resultLength, status)
+    size = ucal_getTimeZoneDisplayName(ucal, utype, localeCode.constData(),
+                                       dst(), size, &status);
+
+    // If overflow, then resize and retry
+    if (size > BigNameLength || status == U_BUFFER_OVERFLOW_ERROR) {
+        result.resize(size);
+        status = U_ZERO_ERROR;
+        size = ucal_getTimeZoneDisplayName(ucal, utype, localeCode.constData(),
+                                           dst(), size, &status);
+    }
+
+    if (!U_SUCCESS(status))
+        return QString();
+
+    // Resize and return:
+    result.resize(size);
+    return result;
+}
+
+} // QtTimeZoneLocale
+
+// Used by TZ backends when ICU is available:
+QString QTimeZonePrivate::localeName(qint64 atMSecsSinceEpoch, int offsetFromUtc,
+                                     QTimeZone::TimeType timeType,
+                                     QTimeZone::NameType nameType,
+                                     const QLocale &locale) const
+{
+    Q_UNUSED(atMSecsSinceEpoch);
+    // TODO: use CLDR data for the offset name.
+    // No ICU API for offset formats, so fall back to our ISO one, even if
+    // locale isn't C:
+    if (nameType == QTimeZone::OffsetName)
+        return isoOffsetFormat(offsetFromUtc);
+
+    const QString id = QString::fromUtf8(m_id);
+    const QByteArray loc = locale.name().toUtf8();
+    UErrorCode status = U_ZERO_ERROR;
+    UCalendar *ucal = ucal_open(reinterpret_cast<const UChar *>(id.data()), id.size(),
+                                loc.constData(), UCAL_DEFAULT, &status);
+    if (ucal && U_SUCCESS(status)) {
+        auto tidier = qScopeGuard([ucal]() { ucal_close(ucal); });
+        return QtTimeZoneLocale::ucalTimeZoneDisplayName(ucal, timeType, nameType, loc);
+    }
+    return QString();
+}
+#else // No ICU, use QTZ[LP}_data_p.h data for feature timezone_locale.
+namespace {
+using namespace QtTimeZoneLocale; // QTZL_data_p.h
+using namespace QtTimeZoneCldr; // QTZP_data_p.h
+// Accessors for the QTZL_data_p.h
+
+// Accessors for the QTZP_data_p.h
+
+} // nameless namespace
+
+QString QTimeZonePrivate::localeName(qint64 atMSecsSinceEpoch, int offsetFromUtc,
+                                     QTimeZone::TimeType timeType,
+                                     QTimeZone::NameType nameType,
+                                     const QLocale &locale) const
+{
+    Q_ASSERT(nameType != QTimeZone::OffsetName || locale.language() != QLocale::C);
+    // Get data from QTZ[LP]_data_p.h
+
+    Q_UNUSED(atMSecsSinceEpoch);
+    Q_UNUSED(offsetFromUtc);
+    Q_UNUSED(timeType);
+    return QString();
+}
+#endif // ICU
+
+QT_END_NAMESPACE