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Use QDateTimePrivate's methods in preference to std::numeric_limits

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The methods give them more appropriate names. This revealed one place
where the min() that's actually invalidMSecs() was being used for a
time that should have been in the supported range, so amend that to
use minMSecs(). Replaced a use of invalidMSecs() + 1 with minMSecs(),
to which it is equal, as that was the meaning it was used for.

At the same time, make those methods constexpr (because they are) and
[[nodiscard]], since their values should be used, while dropping their
fatuous inline (the bodies are inline in the declarations).

Pick-to: 6.3
Change-Id: Idcd51c55850573372b44e6fcf08d5d2665b8a60e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Edward Welbourne 2022-02-23 12:15:54 +01:00
parent 5133ed072a
commit 8024498a36
3 changed files with 18 additions and 16 deletions
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7
src/corelib/time/qtimezoneprivate.cpp
View File

@ -224,16 +224,15 @@ QTimeZonePrivate::Data QTimeZonePrivate::dataForLocalTime(qint64 forLocalMSecs,
std::integral_constant<qint64, 16 * 3600 * 1000> sixteenHoursInMSecs;
static_assert(-sixteenHoursInMSecs / 1000 < QTimeZone::MinUtcOffsetSecs
&& sixteenHoursInMSecs / 1000 > QTimeZone::MaxUtcOffsetSecs);
using Bound = std::numeric_limits<qint64>;
qint64 millis;
const qint64 recent =
sub_overflow(forLocalMSecs, sixteenHoursInMSecs, &millis)
? Bound::min() : millis;
? minMSecs() : millis;
const qint64 imminent =
add_overflow(forLocalMSecs, sixteenHoursInMSecs, &millis)
? Bound::max() : millis;
? maxMSecs() : millis;
// At most one of those took the boundary value:
Q_ASSERT(recent < imminent && sixteenHoursInMSecs < imminent - recent);
Q_ASSERT(recent < imminent && sixteenHoursInMSecs < imminent - recent + 1);
/*
Offsets are Local - UTC, positive to the east of Greenwich, negative to
the west; DST offset always exceeds standard offset, when DST applies.

12
src/corelib/time/qtimezoneprivate_p.h
View File

@ -137,10 +137,14 @@ public:
virtual void serialize(QDataStream &ds) const;
// Static Utility Methods
static inline qint64 maxMSecs() { return (std::numeric_limits<qint64>::max)(); }
static inline qint64 minMSecs() { return (std::numeric_limits<qint64>::min)() + 1; }
static inline qint64 invalidMSecs() { return (std::numeric_limits<qint64>::min)(); }
static inline qint64 invalidSeconds() { return (std::numeric_limits<int>::min)(); }
[[nodiscard]] static constexpr qint64 maxMSecs()
{ return (std::numeric_limits<qint64>::max)(); }
[[nodiscard]] static constexpr qint64 minMSecs()
{ return (std::numeric_limits<qint64>::min)() + 1; }
[[nodiscard]] static constexpr qint64 invalidMSecs()
{ return (std::numeric_limits<qint64>::min)(); }
[[nodiscard]] static constexpr qint64 invalidSeconds()
{ return (std::numeric_limits<int>::min)(); }
static Data invalidData();
static QTimeZone::OffsetData invalidOffsetData();
static QTimeZone::OffsetData toOffsetData(const Data &data);

15
src/corelib/time/qtimezoneprivate_win.cpp
View File

@ -310,13 +310,13 @@ qint64 calculateTransitionForYear(const SYSTEMTIME &rule, int year, int bias)
const QDate date = calculateTransitionLocalDate(rule, year);
const QTime time = QTime(rule.wHour, rule.wMinute, rule.wSecond);
qint64 msecs = 0;
using Bound = std::numeric_limits<qint64>;
if (date.isValid() && time.isValid() && !timeToMSecs(date, time, &msecs)) {
// If bias pushes us outside representable range, clip to range - and
// exclude min() from range as it's invalidMSecs():
// If bias pushes us outside the representable range, clip to range
// (overflow went past the end bias pushed us towards; and
// invalidMSecs() is a representable value less than minMSecs()):
return bias && add_overflow(msecs, qint64(bias) * 60000, &msecs)
? (bias < 0 ? Bound::min() + 1 : Bound::max())
: (msecs == Bound::min() ? msecs + 1 : msecs);
? (bias < 0 ? QTimeZonePrivate::minMSecs() : QTimeZonePrivate::maxMSecs())
: qMax(QTimeZonePrivate::minMSecs(), msecs);
}
return QTimeZonePrivate::invalidMSecs();
}
@ -730,8 +730,7 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::nextTransition(qint64 afterMSecsSinc
QTimeZonePrivate::Data QWinTimeZonePrivate::previousTransition(qint64 beforeMSecsSinceEpoch) const
{
const qint64 startOfTime = invalidMSecs() + 1;
if (beforeMSecsSinceEpoch <= startOfTime)
if (beforeMSecsSinceEpoch <= minMSecs())
return invalidData();
int year = msecsToDate(beforeMSecsSinceEpoch).year();
@ -764,7 +763,7 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::previousTransition(qint64 beforeMSec
// Treat a no-transition first rule as a transition at the start of
// time, so that a scan through all rules *does* see it as the first
// rule:
return ruleToData(rule, startOfTime, QTimeZone::StandardTime, false);
return ruleToData(rule, minMSecs(), QTimeZone::StandardTime, false);
} // else: no transition during rule's period
if (year >= rule.startYear) {
year = rule.startYear - 1; // Seek last transition in new rule