diff options
| -rw-r--r-- | src/corelib/tools/qtimezoneprivate_p.h | 2 | ||||
| -rw-r--r-- | src/corelib/tools/qtimezoneprivate_win.cpp | 121 |
2 files changed, 106 insertions, 17 deletions
diff --git a/src/corelib/tools/qtimezoneprivate_p.h b/src/corelib/tools/qtimezoneprivate_p.h index 9b7adbbbbe..ca36f9d297 100644 --- a/src/corelib/tools/qtimezoneprivate_p.h +++ b/src/corelib/tools/qtimezoneprivate_p.h @@ -432,7 +432,7 @@ public: private: void init(const QByteArray &ianaId); QTimeZonePrivate::Data ruleToData(const QWinTransitionRule &rule, qint64 atMSecsSinceEpoch, - QTimeZone::TimeType type) const; + QTimeZone::TimeType type, bool fakeDst = false) const; QByteArray m_windowsId; QString m_displayName; diff --git a/src/corelib/tools/qtimezoneprivate_win.cpp b/src/corelib/tools/qtimezoneprivate_win.cpp index ba6a33e729..56fdd5b181 100644 --- a/src/corelib/tools/qtimezoneprivate_win.cpp +++ b/src/corelib/tools/qtimezoneprivate_win.cpp @@ -401,14 +401,82 @@ struct TransitionTimePair { // Transition times after the epoch, in ms: qint64 std, dst; - TransitionTimePair(const QWinTimeZonePrivate::QWinTransitionRule &rule, int year) + // If either is invalidMSecs(), which shall then be < the other, there is no + // DST and the other describes a change in actual standard offset. + + TransitionTimePair(const QWinTimeZonePrivate::QWinTransitionRule &rule, + int year, int oldYearOffset) // The local time in Daylight Time of the switch to Standard Time : std(calculateTransitionForYear(rule.standardTimeRule, year, rule.standardTimeBias + rule.daylightTimeBias)), // The local time in Standard Time of the switch to Daylight Time dst(calculateTransitionForYear(rule.daylightTimeRule, year, rule.standardTimeBias)) - {} + { + /* + Check for potential "fake DST", used by MS's APIs because the + TIME_ZONE_INFORMATION spec either expresses no transitions in the + year, or expresses a transition of each kind, even if standard time + did change in a year with no DST. We've seen year-start fake-DST + (whose offset matches prior standard offset, in which the previous + year ended); and conjecture that similar might be used at a year-end. + (This might be used for a southern-hemisphere zone, where the start of + the year usually is in DST, when applicable.) Note that, here, wDay + identifies an instance of a given day-of-week in the month, with 5 + meaning last. + + Either the alleged standardTimeRule or the alleged daylightTimeRule + may be faked; either way, the transition is actually a change to the + current standard offset; but the unfaked half of the rule contains the + useful bias data, so we have to go along with its lies. + + Example: Russia/Moscow + Format: -bias +( -stdBias, stdDate | -dstBias, dstDate ) notes + Last year of DST, 2010: 180 +( 0, 0-10-5 3:0 | 60, 0-3-5 2:0 ) normal DST + Zone change in 2011: 180 +( 0, 0-1-1 0:0 | 60 0-3-5 2:0 ) fake DST at transition + Fixed standard in 2012: 240 +( 0, 0-0-0 0:0 | 60, 0-0-0 0:0 ) standard time years + Zone change in 2014: 180 +( 0, 0-10-5 2:0 | 60, 0-1-1 0:0 ) fake DST at year-start + The last of these is missing on Win7 VMs (too old to know about it). + */ + if (rule.daylightTimeRule.wMonth == 1 && rule.daylightTimeRule.wDay == 1) { + // Fake "DST transition" at start of year producing the same offset as + // previous year ended in. + if (rule.standardTimeBias + rule.daylightTimeBias == oldYearOffset) + dst = QTimeZonePrivate::invalidMSecs(); + } else if (rule.daylightTimeRule.wMonth == 12 && rule.daylightTimeRule.wDay > 3) { + // Similar, conjectured, for end of year, not changing offset. + if (rule.daylightTimeBias == 0) + dst = QTimeZonePrivate::invalidMSecs(); + } + if (rule.standardTimeRule.wMonth == 1 && rule.standardTimeRule.wDay == 1) { + // Fake "transition out of DST" at start of year producing the same + // offset as previous year ended in. + if (rule.standardTimeBias == oldYearOffset) + std = QTimeZonePrivate::invalidMSecs(); + } else if (rule.standardTimeRule.wMonth == 12 && rule.standardTimeRule.wDay > 3) { + // Similar, conjectured, for end of year, not changing offset. + if (rule.daylightTimeBias == 0) + std = QTimeZonePrivate::invalidMSecs(); + } + } + + bool fakesDst() const + { + return std == QTimeZonePrivate::invalidMSecs() + || dst == QTimeZonePrivate::invalidMSecs(); + } }; + +int yearEndOffset(const QWinTimeZonePrivate::QWinTransitionRule &rule, int year) +{ + int offset = rule.standardTimeBias; + // Only needed to help another TransitionTimePair work out year + 1's start + // offset; and the oldYearOffset we use only affects an alleged transition + // at the *start* of this year, so it doesn't matter if we guess wrong here: + TransitionTimePair pair(rule, year, offset); + if (pair.dst > pair.std) + offset += rule.daylightTimeBias; + return offset; +} } // anonymous namespace static QLocale::Country userCountry() @@ -665,18 +733,22 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::data(qint64 forMSecsSinceEpoch) cons if (rule.standardTimeRule.wMonth > 0 || rule.daylightTimeRule.wMonth > 0) { const int endYear = qMax(rule.startYear, year - 1); while (year >= endYear) { - const TransitionTimePair pair(rule, year); + const int newYearOffset = (year <= rule.startYear && ruleIndex > 0) + ? yearEndOffset(m_tranRules.at(ruleIndex - 1), year - 1) + : yearEndOffset(rule, year - 1); + const TransitionTimePair pair(rule, year, newYearOffset); bool isDst = false; - if (pair.std <= forMSecsSinceEpoch) { + if (pair.std != invalidMSecs() && pair.std <= forMSecsSinceEpoch) { isDst = pair.std < pair.dst && pair.dst <= forMSecsSinceEpoch; - } else if (pair.dst <= forMSecsSinceEpoch) { + } else if (pair.dst != invalidMSecs() && pair.dst <= forMSecsSinceEpoch) { isDst = true; } else { --year; // Try an earlier year for this rule (once). continue; } return ruleToData(rule, forMSecsSinceEpoch, - isDst ? QTimeZone::DaylightTime : QTimeZone::StandardTime); + isDst ? QTimeZone::DaylightTime : QTimeZone::StandardTime, + pair.fakesDst()); } // Fell off start of rule, try previous rule. } else { @@ -711,21 +783,28 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::nextTransition(qint64 afterMSecsSinc year = rule.startYear; // Seek first transition in this rule. const int endYear = ruleIndex + 1 < m_tranRules.count() ? qMin(m_tranRules.at(ruleIndex + 1).startYear, year + 2) : (year + 2); + int newYearOffset = (year <= rule.startYear && ruleIndex > 0) + ? yearEndOffset(m_tranRules.at(ruleIndex - 1), year - 1) + : yearEndOffset(rule, year - 1); while (year < endYear) { - const TransitionTimePair pair(rule, year); + const TransitionTimePair pair(rule, year, newYearOffset); bool isDst = false; + Q_ASSERT(invalidMSecs() <= afterMSecsSinceEpoch); // invalid is min qint64 if (pair.std > afterMSecsSinceEpoch) { isDst = pair.std > pair.dst && pair.dst > afterMSecsSinceEpoch; } else if (pair.dst > afterMSecsSinceEpoch) { isDst = true; } else { + newYearOffset = rule.standardTimeBias; + if (pair.dst > pair.std) + newYearOffset += rule.daylightTimeBias; ++year; // Try a later year for this rule (once). continue; } if (isDst) - return ruleToData(rule, pair.dst, QTimeZone::DaylightTime); - return ruleToData(rule, pair.std, QTimeZone::StandardTime); + return ruleToData(rule, pair.dst, QTimeZone::DaylightTime, pair.fakesDst()); + return ruleToData(rule, pair.std, QTimeZone::StandardTime, pair.fakesDst()); } // Fell off end of rule, try next rule. } // else: no transition during rule's period @@ -744,19 +823,22 @@ QTimeZonePrivate::Data QWinTimeZonePrivate::previousTransition(qint64 beforeMSec if (rule.standardTimeRule.wMonth > 0 || rule.daylightTimeRule.wMonth > 0) { const int endYear = qMax(rule.startYear, year - 1); while (year >= endYear) { - const TransitionTimePair pair(rule, year); + const int newYearOffset = (year <= rule.startYear && ruleIndex > 0) + ? yearEndOffset(m_tranRules.at(ruleIndex - 1), year - 1) + : yearEndOffset(rule, year - 1); + const TransitionTimePair pair(rule, year, newYearOffset); bool isDst = false; - if (pair.std < beforeMSecsSinceEpoch) { + if (pair.std != invalidMSecs() && pair.std < beforeMSecsSinceEpoch) { isDst = pair.std < pair.dst && pair.dst < beforeMSecsSinceEpoch; - } else if (pair.dst < beforeMSecsSinceEpoch) { + } else if (pair.dst != invalidMSecs() && pair.dst < beforeMSecsSinceEpoch) { isDst = true; } else { --year; // Try an earlier year for this rule (once). continue; } if (isDst) - return ruleToData(rule, pair.dst, QTimeZone::DaylightTime); - return ruleToData(rule, pair.std, QTimeZone::StandardTime); + return ruleToData(rule, pair.dst, QTimeZone::DaylightTime, pair.fakesDst()); + return ruleToData(rule, pair.std, QTimeZone::StandardTime, pair.fakesDst()); } // Fell off start of rule, try previous rule. } // else: no transition during rule's period @@ -798,12 +880,19 @@ QList<QByteArray> QWinTimeZonePrivate::availableTimeZoneIds() const QTimeZonePrivate::Data QWinTimeZonePrivate::ruleToData(const QWinTransitionRule &rule, qint64 atMSecsSinceEpoch, - QTimeZone::TimeType type) const + QTimeZone::TimeType type, + bool fakeDst) const { Data tran = invalidData(); tran.atMSecsSinceEpoch = atMSecsSinceEpoch; tran.standardTimeOffset = rule.standardTimeBias * -60; - if (type == QTimeZone::DaylightTime) { + if (fakeDst) { + tran.daylightTimeOffset = 0; + tran.abbreviation = m_standardName; + // Rule may claim we're in DST when it's actually a standard time change: + if (type == QTimeZone::DaylightTime) + tran.standardTimeOffset += rule.daylightTimeBias * -60; + } else if (type == QTimeZone::DaylightTime) { tran.daylightTimeOffset = rule.daylightTimeBias * -60; tran.abbreviation = m_daylightName; } else { |