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authorEdward Welbourne <edward.welbourne@qt.io>2017-11-07 10:58:03 +0100
committerEdward Welbourne <edward.welbourne@qt.io>2017-11-30 20:20:15 +0000
commit6deb0f0dcc202e1be08cb6a2284da266cd0fa956 (patch)
treeffe63e118e345d2abb029905f0853fbbdfa4bb74
parent35176c22896a6c633408907e8113c3f1b9a846b0 (diff)
Fake a "first transition" at the start of time
QTimeZonePrivate::dataForLocalTime() needs a transition before the time it starts at; MS's time-zone data tends to omit old zones (before 2007, in the case of Win7 for Casablanca - which had interesting transitions before that), so all we can do is extrapolate backwards from there; but a first rule is indeed apt to be a no-transition rule, describing the zone's status up to the first known transition. So fake a "start of time" transition to return for this case, that describes this prefix of history. Change-Id: Iaf178cbebc3b1e599cbde3437a0af75d9f6ca432 Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
-rw-r--r--src/corelib/tools/qtimezoneprivate_win.cpp9
1 files changed, 9 insertions, 0 deletions
diff --git a/src/corelib/tools/qtimezoneprivate_win.cpp b/src/corelib/tools/qtimezoneprivate_win.cpp
index 56fdd5b181..8de95e9c73 100644
--- a/src/corelib/tools/qtimezoneprivate_win.cpp
+++ b/src/corelib/tools/qtimezoneprivate_win.cpp
@@ -815,6 +815,10 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::nextTransition(qint64 afterMSecsSinc
QTimeZonePrivate::Data QWinTimeZonePrivate::previousTransition(qint64 beforeMSecsSinceEpoch) const
{
+ const qint64 startOfTime = invalidMSecs() + 1;
+ if (beforeMSecsSinceEpoch <= startOfTime)
+ return invalidData();
+
int year = msecsToDate(beforeMSecsSinceEpoch).year();
for (int ruleIndex = ruleIndexForYear(m_tranRules, year);
ruleIndex >= 0; --ruleIndex) {
@@ -841,6 +845,11 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::previousTransition(qint64 beforeMSec
return ruleToData(rule, pair.std, QTimeZone::StandardTime, pair.fakesDst());
}
// Fell off start of rule, try previous rule.
+ } else if (ruleIndex == 0) {
+ // 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);
} // else: no transition during rule's period
if (year >= rule.startYear)
year = rule.startYear - 1; // Seek last transition in new rule