Fix QDateTime::toString(Qt::ISODate)'s handling of Qt::TimeZone

When the time is specified relative to a zone, the ISO date produced
lacked its offset suffix; all zones were treated as if they were local
time.  Handle zone as for an offset from UTC and ensure we do set the
date-time objects's offset from UTC when it's zone-based.

Change-Id: I7c9896bb8ec0a9d89df14a6e94b005174ab9e943
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 17 insertions, 2 deletions

diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp
index d52f03acae..4337a4d13f 100644
--- a/src/corelib/tools/qdatetime.cpp
+++ b/src/corelib/tools/qdatetime.cpp
@@ -2576,6 +2576,13 @@ static inline Qt::TimeSpec getSpec(const QDateTimeData &d)
     return extractSpec(getStatus(d));
 }
 
+#if QT_CONFIG(timezone)
+void QDateTimePrivate::setUtcOffsetByTZ(qint64 atMSecsSinceEpoch)
+{
+    m_offsetFromUtc = m_timeZone.d->offsetFromUtc(atMSecsSinceEpoch);
+}
+#endif
+
 // Refresh the LocalTime validity and offset
 static void refreshDateTime(QDateTimeData &d)
 {
@@ -2591,10 +2598,12 @@ static void refreshDateTime(QDateTimeData &d)
 #if QT_CONFIG(timezone)
     // If not valid time zone then is invalid
     if (spec == Qt::TimeZone) {
-        if (!d->m_timeZone.isValid())
+        if (!d->m_timeZone.isValid()) {
             status &= ~QDateTimePrivate::ValidDateTime;
-        else
+        } else {
             epochMSecs = QDateTimePrivate::zoneMSecsToEpochMSecs(msecs, d->m_timeZone, extractDaylightStatus(status), &testDate, &testTime);
+            d->setUtcOffsetByTZ(epochMSecs);
+        }
     }
 #endif // timezone
 
@@ -3822,6 +3831,9 @@ QString QDateTime::toString(Qt::DateFormat format) const
             buf += QLatin1Char('Z');
             break;
         case Qt::OffsetFromUTC:
+#if QT_CONFIG(timezone)
+        case Qt::TimeZone:
+#endif
             buf += toOffsetString(Qt::ISODate, offsetFromUtc());
             break;
         default:
diff --git a/src/corelib/tools/qdatetime_p.h b/src/corelib/tools/qdatetime_p.h
index a217990c8d..b8f6736ac4 100644
--- a/src/corelib/tools/qdatetime_p.h
+++ b/src/corelib/tools/qdatetime_p.h
@@ -136,6 +136,9 @@ public:
     static qint64 zoneMSecsToEpochMSecs(qint64 msecs, const QTimeZone &zone,
                                         DaylightStatus hint = UnknownDaylightTime,
                                         QDate *localDate = 0, QTime *localTime = 0);
+
+    // Inlined for its one caller in qdatetime.cpp
+    inline void setUtcOffsetByTZ(qint64 atMSecsSinceEpoch);
 #endif // timezone
 
     static inline qint64 minJd() { return QDate::minJd(); }