From 84b9d071630a63a493773f612eefe83c8e68390d Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Thu, 5 Mar 2015 15:27:32 -0800 Subject: Silence bogus MSVC warning about variable not used The compiler is wrong: the variable was used in the previous line. However, the line had no effect for a type T that has a trivial destructor, so the optimizer must have discarded the line and the reference to the variable before the checker for used variables. qsharedpointer_impl.h(247) : warning C4189: 'that' : local variable is initialized but not referenced Change-Id: Ia0aac2f09e9245339951ffff13c8bde02bb46816 Reviewed-by: Olivier Goffart (Woboq GmbH) --- src/corelib/tools/qsharedpointer_impl.h | 1 + 1 file changed, 1 insertion(+) (limited to 'src/corelib/tools') diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h index 8cccc83e9d..9e6b48a97d 100644 --- a/src/corelib/tools/qsharedpointer_impl.h +++ b/src/corelib/tools/qsharedpointer_impl.h @@ -247,6 +247,7 @@ namespace QtSharedPointer { ExternalRefCountWithContiguousData *that = static_cast(self); that->data.~T(); + Q_UNUSED(that); // MSVC warns if T has a trivial destructor } static void safetyCheckDeleter(ExternalRefCountData *self) { -- cgit v1.2.3 From a8c74ddcf78604c9038ba2a2bea81e445e4b3c58 Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Wed, 14 Jan 2015 16:33:03 -0800 Subject: Fix race condition in QDateTime::timeZone() and other methods When timezone support for QDateTime was added, we decided it was a good idea to delay creating the QTimeZone object and checking that the time is valid in that timezone (including for local time) until the user requested that information. Unfortunately, QExplicitlySharedDataPointer returns a non-const T* in operator->(), which meant we were accidentally modifying the d pointer's contents in const methods, which in turn means those const methods were not thread-safe when operating on the same object. This commit changes the d pointer to QSharedDataPointer, which is safer in this regard and pointed out where the issues with constness were located. Since we can't lazily calculate QTimeZone anymore, we need to do it whenever the date, time or offset changes. Task-number: QTBUG-43703 Change-Id: Ic5d393bfd36e48a193fcffff13b9686ef4ef1454 Reviewed-by: Lars Knoll --- src/corelib/tools/qdatetime.cpp | 55 ++++++++++++++++++++++------------------- src/corelib/tools/qdatetime.h | 2 +- src/corelib/tools/qdatetime_p.h | 14 ++++------- 3 files changed, 36 insertions(+), 35 deletions(-) (limited to 'src/corelib/tools') diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp index eeefea8137..e5fbf5af5e 100644 --- a/src/corelib/tools/qdatetime.cpp +++ b/src/corelib/tools/qdatetime.cpp @@ -2607,7 +2607,6 @@ QDateTimePrivate::QDateTimePrivate(const QDate &toDate, const QTime &toTime, void QDateTimePrivate::setTimeSpec(Qt::TimeSpec spec, int offsetSeconds) { clearValidDateTime(); - clearTimeZoneCached(); clearSetToDaylightStatus(); #ifndef QT_BOOTSTRAPPED @@ -2707,27 +2706,44 @@ QDateTimePrivate::DaylightStatus QDateTimePrivate::daylightStatus() const return UnknownDaylightTime; } +qint64 QDateTimePrivate::toMSecsSinceEpoch() const +{ + switch (m_spec) { + case Qt::OffsetFromUTC: + case Qt::UTC: + return (m_msecs - (m_offsetFromUtc * 1000)); + + case Qt::LocalTime: + // recalculate the local timezone + return localMSecsToEpochMSecs(m_msecs); + + case Qt::TimeZone: +#ifndef QT_BOOTSTRAPPED + return zoneMSecsToEpochMSecs(m_msecs, m_timeZone); +#endif + break; + } + Q_UNREACHABLE(); + return 0; +} + // Check the UTC / offsetFromUTC validity void QDateTimePrivate::checkValidDateTime() { switch (m_spec) { case Qt::OffsetFromUTC: case Qt::UTC: + // for these, a valid date and a valid time imply a valid QDateTime if (isValidDate() && isValidTime()) setValidDateTime(); else clearValidDateTime(); break; case Qt::TimeZone: - // Defer checking until required as can be expensive - clearValidDateTime(); - clearTimeZoneCached(); - m_offsetFromUtc = 0; - break; case Qt::LocalTime: - // Defer checking until required as can be expensive - clearValidDateTime(); - m_offsetFromUtc = 0; + // for these, we need to check whether the timezone is valid and whether + // the time is valid in that timezone. Expensive, but no other option. + refreshDateTime(); break; } } @@ -2741,12 +2757,6 @@ void QDateTimePrivate::refreshDateTime() // Always set by setDateTime so just return return; case Qt::TimeZone: - // If already cached then don't need to refresh as tz won't change - if (isTimeZoneCached()) - return; - // Flag that will have a cached result after calculations - setTimeZoneCached(); - break; case Qt::LocalTime: break; } @@ -3082,7 +3092,6 @@ bool QDateTime::isNull() const bool QDateTime::isValid() const { - d->refreshDateTime(); return (d->isValidDateTime()); } @@ -3143,13 +3152,11 @@ Qt::TimeSpec QDateTime::timeSpec() const QTimeZone QDateTime::timeZone() const { switch (d->m_spec) { - case Qt::OffsetFromUTC: - if (!d->m_timeZone.isValid()) - d->m_timeZone = QTimeZone(d->m_offsetFromUtc); - return d->m_timeZone; case Qt::UTC: return QTimeZone::utc(); + case Qt::OffsetFromUTC: case Qt::TimeZone: + Q_ASSERT(d->m_timeZone.isValid()); return d->m_timeZone; case Qt::LocalTime: return QTimeZone::systemTimeZone(); @@ -3178,7 +3185,6 @@ QTimeZone QDateTime::timeZone() const int QDateTime::offsetFromUtc() const { - d->refreshDateTime(); return d->m_offsetFromUtc; } @@ -3350,7 +3356,7 @@ void QDateTime::setTimeZone(const QTimeZone &toZone) d->m_spec = Qt::TimeZone; d->m_offsetFromUtc = 0; d->m_timeZone = toZone; - d->m_status = d->m_status & ~QDateTimePrivate::ValidDateTime & ~QDateTimePrivate::TimeZoneCached; + d->refreshDateTime(); } #endif // QT_BOOTSTRAPPED @@ -3371,7 +3377,6 @@ void QDateTime::setTimeZone(const QTimeZone &toZone) */ qint64 QDateTime::toMSecsSinceEpoch() const { - d->refreshDateTime(); return d->toMSecsSinceEpoch(); } @@ -3453,8 +3458,8 @@ void QDateTime::setMSecsSinceEpoch(qint64 msecs) d->m_status = d->m_status | QDateTimePrivate::ValidDate | QDateTimePrivate::ValidTime - | QDateTimePrivate::ValidDateTime - | QDateTimePrivate::TimeZoneCached; + | QDateTimePrivate::ValidDateTime; + d->refreshDateTime(); #endif // QT_BOOTSTRAPPED break; case Qt::LocalTime: { diff --git a/src/corelib/tools/qdatetime.h b/src/corelib/tools/qdatetime.h index 784aced71a..88288872df 100644 --- a/src/corelib/tools/qdatetime.h +++ b/src/corelib/tools/qdatetime.h @@ -326,7 +326,7 @@ private: // ### Qt6: Using a private here has high impact on runtime // on users such as QFileInfo. In Qt 6, the data members // should be inlined. - QExplicitlySharedDataPointer d; + QSharedDataPointer d; #ifndef QT_NO_DATASTREAM friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QDateTime &); diff --git a/src/corelib/tools/qdatetime_p.h b/src/corelib/tools/qdatetime_p.h index a139390a9d..b8934f7f70 100644 --- a/src/corelib/tools/qdatetime_p.h +++ b/src/corelib/tools/qdatetime_p.h @@ -79,10 +79,9 @@ public: enum StatusFlag { NullDate = 0x01, NullTime = 0x02, - ValidDate = 0x04, - ValidTime = 0x08, - ValidDateTime = 0x10, - TimeZoneCached = 0x20, + ValidDate = 0x04, // just the date field + ValidTime = 0x08, // just the time field + ValidDateTime = 0x10, // the whole object (including timezone) SetToStandardTime = 0x40, SetToDaylightTime = 0x80 }; @@ -120,7 +119,7 @@ public: DaylightStatus daylightStatus() const; // Returns msecs since epoch, assumes offset value is current - inline qint64 toMSecsSinceEpoch() const { return (m_msecs - (m_offsetFromUtc * 1000)); } + inline qint64 toMSecsSinceEpoch() const; void checkValidDateTime(); void refreshDateTime(); @@ -133,14 +132,11 @@ public: inline bool isValidDateTime() const { return m_status & ValidDateTime; } inline void setValidDateTime() { m_status |= ValidDateTime; } inline void clearValidDateTime() { m_status &= ~ValidDateTime; } - inline bool isTimeZoneCached() const { return m_status & TimeZoneCached; } - inline void setTimeZoneCached() { m_status |= TimeZoneCached; } - inline void clearTimeZoneCached() { m_status &= ~TimeZoneCached; } inline void clearSetToDaylightStatus() { m_status &= ~(SetToStandardTime | SetToDaylightTime); } #ifndef QT_BOOTSTRAPPED static qint64 zoneMSecsToEpochMSecs(qint64 msecs, const QTimeZone &zone, - QDate *localDate, QTime *localTime); + QDate *localDate = 0, QTime *localTime = 0); #endif // QT_BOOTSTRAPPED static inline qint64 minJd() { return QDate::minJd(); } -- cgit v1.2.3 From 53ce0d1a31c8ebb54952887b8bcf769843d50d9c Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Wed, 4 Mar 2015 09:33:42 -0800 Subject: QStringAlgorithms::simplified_helper: add missing check for detached Otherwise, we modify shared strings that happened to be rvalues. Task-number: QTBUG-44706 Change-Id: Ia0aac2f09e9245339951ffff13c85bfc912f03d1 Reviewed-by: Friedemann Kleint --- src/corelib/tools/qstringalgorithms_p.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/corelib/tools') diff --git a/src/corelib/tools/qstringalgorithms_p.h b/src/corelib/tools/qstringalgorithms_p.h index 1481b194eb..b4be5c7ec7 100644 --- a/src/corelib/tools/qstringalgorithms_p.h +++ b/src/corelib/tools/qstringalgorithms_p.h @@ -114,7 +114,7 @@ template struct QStringAlgorithms return str; const Char *src = str.cbegin(); const Char *end = str.cend(); - NakedStringType result = isConst ? + NakedStringType result = isConst || !str.isDetached() ? StringType(str.size(), Qt::Uninitialized) : qMove(str); -- cgit v1.2.3