AuroraMiddleware/qt5base-lts
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Rework massageAdjusted and make the most of its DST knowledge

Browse Source 
Since massageAdjustedDateTime() has to split LocalTime from TimeZone
and call {local,zone}MSecsToEpochMSecs() in any case, its call to
refreshZonedDateTime(), via checkValidDateTime(), was duplicating that
work uselessly. So handle UTC and offset-from-UTC separately with a
call to refreshSimple and handle local/zone time by inlining what
remains of refreshZonedDateTime() aside from the duplication.

At the same time, recent reworking of qt_mktime() make
localMSecsToEpochMSecs() handle its DST-hint the same way
zoneMSecsToEpochMSecs() has long done so, to take care of the intended
handling of DST gaps and repeats.

Change-Id: Id6bef7dd0f8983c3e923f4580a62a76aa6fcb810
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
This commit is contained in:
Edward Welbourne 2021-02-26 14:27:34 +01:00
parent 1bf75f2a66
commit 76c8a988d2
1 changed files with 42 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
src/corelib/time/qdatetime.cpp
View File

@ -4323,27 +4323,51 @@ static inline void massageAdjustedDateTime(QDateTimeData &d, QDate date, QTime t
If we have just adjusted to a day with a DST transition, our given time
may lie in the transition hour (either missing or duplicated). For any
other time, telling mktime (deep in the bowels of localMSecsToEpochMSecs)
we don't know its DST-ness will produce no adjustment (just a decision as
to its DST-ness); but for a time in spring's missing hour it'll adjust the
time while picking a DST-ness. (Handling of autumn is trickier, as either
DST-ness is valid, without adjusting the time. We might want to propagate
the daylight status in that case, but it's hard to do so without breaking
(far more common) other cases; and it makes little difference, as the two
answers do then differ only in DST-ness.)
or QTimeZone (via zoneMSecsToEpochMSecs) what we know about DST-ness, of
the time we adjusted from, will make no difference; it'll just tell us the
actual DST-ness of the given time. When landing in a transition that
repeats an hour, passing the prior DST-ness - when known - will get us the
indicated side of the duplicate (either local or zone). When landing in a
gap, the zone gives us the other side of the gap but (for now) local time
gets us a platform-dependent side of the gap (e.g. DST-side for glibc).
*/
auto spec = getSpec(d);
if (spec == Qt::LocalTime) {
QDateTimePrivate::DaylightStatus status = QDateTimePrivate::UnknownDaylightTime;
QDateTimePrivate::localMSecsToEpochMSecs(timeToMSecs(date, time), &status, &date, &time);
#if QT_CONFIG(timezone)
} else if (spec == Qt::TimeZone && d->m_timeZone.isValid()) {
QDateTimePrivate::DaylightStatus status = QDateTimePrivate::UnknownDaylightTime;
QDateTimePrivate::zoneMSecsToEpochMSecs(timeToMSecs(date, time),
d->m_timeZone, &status, &date, &time);
#endif // timezone
auto status = getStatus(d);
Q_ASSERT((status & QDateTimePrivate::ValidDate) && (status & QDateTimePrivate::ValidTime)
&& (status & QDateTimePrivate::ValidDateTime));
auto spec = extractSpec(status);
if (spec == Qt::OffsetFromUTC || spec == Qt::UTC) {
setDateTime(d, date, time);
refreshSimpleDateTime(d);
return;
}
auto dst = extractDaylightStatus(status);
qint64 utc = 0, local = timeToMSecs(date, time);
if (spec == Qt::LocalTime)
utc = QDateTimePrivate::localMSecsToEpochMSecs(local, &dst, &date, &time);
#if QT_CONFIG(timezone)
else if (spec == Qt::TimeZone && d->m_timeZone.isValid())
utc = QDateTimePrivate::zoneMSecsToEpochMSecs(local, d->m_timeZone, &dst, &date, &time);
#endif // timezone
else
dst = QDateTimePrivate::UnknownDaylightTime;
setDateTime(d, date, time);
checkValidDateTime(d);
status = getStatus(d); // Updated by setDateTime()
const bool ok = (dst != QDateTimePrivate::UnknownDaylightTime
&& (status & QDateTimePrivate::ValidDate)
&& (status & QDateTimePrivate::ValidTime));
if (ok)
status = mergeDaylightStatus(status | QDateTimePrivate::ValidDateTime, dst);
else
status &= ~QDateTimePrivate::ValidDateTime;
if (status & QDateTimePrivate::ShortData) {
d.data.status = status.toInt();
} else {
d->m_status = status;
if (ok)
d->m_offsetFromUtc = (local - utc) / MSECS_PER_SEC;
}
}
/*!