diff options
| author | Ulf Hermann <ulf.hermann@qt.io> | 2020-06-19 10:10:52 +0200 |
|---|---|---|
| committer | Ulf Hermann <ulf.hermann@qt.io> | 2020-06-25 10:09:25 +0200 |
| commit | 510253aa0996a89e6029d244002a08615b2fb65b (patch) | |
| tree | 90f34289ffe658189c2caa495a4b744df9ef0593 /src/qml | |
| parent | 5c672954e391d43e1fb94e6d76aaedc987dea468 (diff) | |
qv4dateobject.cpp: USE_QTZ_SYSTEM_TIMEZONE on more platforms
The only platform where we may have a semi-adequate native
implementation of the time/date functions is windows. On all other
platforms we should use QTimeZone::systemTimeZone() if possible as that
at least gives us correct results when the system time zone doesn't
change at runtime.
Fixes: QTBUG-84474
Pick-to: 5.15
Change-Id: I34b01e12a751ee1c9b17735810e62e2e847f8446
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Diffstat (limited to 'src/qml')
| -rw-r--r-- | src/qml/jsruntime/qv4dateobject.cpp | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/src/qml/jsruntime/qv4dateobject.cpp b/src/qml/jsruntime/qv4dateobject.cpp index 310d393c12..e75d8bc740 100644 --- a/src/qml/jsruntime/qv4dateobject.cpp +++ b/src/qml/jsruntime/qv4dateobject.cpp @@ -54,11 +54,28 @@ #include <wtf/MathExtras.h> -#if defined(Q_OS_LINUX) && QT_CONFIG(timezone) && !defined(Q_OS_ANDROID) +#if QT_CONFIG(timezone) && !defined(Q_OS_WIN) /* See QTBUG-56899. Although we don't (yet) have a proper way to reset the system zone, the code below, that uses QTimeZone::systemTimeZone(), works - adequately on Linux, when the TZ environment variable is changed. + adequately on Linux. + + QTimeZone::systemTimeZone() will automatically produce an updated value on + non-android Linux systems when the TZ environment variable or the relevant + files in /etc are changed. On other platforms it won't, and the information + produced here may be incorrect after changes to the system time zone. + + We accept this defect for now because the localtime_r approach will + consistently produce incorrect results for some time zones, not only when + the system time zone changes. This is a worse problem, see also QTBUG-84474. + + On windows we have a better implementation of getLocalTZA that hopefully + updates on time zone changes. However, we currently use the worse + implementation of DaylightSavingTA (returning either an hour or 0). + + QTimeZone::systemTimeZone() on Linux is also slower than other approaches + because it has to poll the relevant files (if TZ is not set). See + QTBUG-75585 for an explanation and possible workarounds. */ #define USE_QTZ_SYSTEM_ZONE #endif |