cleanup: move timestampToDateTime() to qthelper.cpp

Move this function from maintab.cpp to qthelper.cpp. Since the
functionality was used in numerous places, use the helper function
there as well. This removes a number of inconsistencies. For example,
sometime setTimeSpec(Qt::UTC) was called, even though the
QDateTime object was already created with that time spec.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

4 files changed, 15 insertions, 10 deletions

diff --git a/core/gpslocation.cpp b/core/gpslocation.cpp
index feea645e1..ebd5b1950 100644
--- a/core/gpslocation.cpp
+++ b/core/gpslocation.cpp
@@ -133,7 +133,7 @@ QString GpsLocation::currentPosition()
 	if (!hasLocationsSource())
 		return tr("Unknown GPS location (no GPS source)");
 	if (m_trackers.count()) {
-		QDateTime lastFixTime =	QDateTime().fromMSecsSinceEpoch((m_trackers.lastKey() - gettimezoneoffset(m_trackers.lastKey())) * 1000);
+		QDateTime lastFixTime =	timestampToDateTime(m_trackers.lastKey() - gettimezoneoffset(m_trackers.lastKey()));
 		QDateTime now = QDateTime::currentDateTime();
 		int delta = lastFixTime.secsTo(now);
 		qDebug() << "lastFixTime" << lastFixTime.toString() << "now" << now.toString() << "delta" << delta;
@@ -173,7 +173,7 @@ void GpsLocation::newPosition(QGeoPositionInfo pos)
 	if (!nr || waitingForPosition || delta > prefs.time_threshold ||
 	    lastCoord.distanceTo(pos.coordinate()) > prefs.distance_threshold) {
 		QString msg = QStringLiteral("received new position %1 after delta %2 threshold %3 (now %4 last %5)");
-		status(qPrintable(msg.arg(pos.coordinate().toString()).arg(delta).arg(prefs.time_threshold).arg(pos.timestamp().toString()).arg(QDateTime().fromMSecsSinceEpoch(lastTime * 1000).toString())));
+		status(qPrintable(msg.arg(pos.coordinate().toString()).arg(delta).arg(prefs.time_threshold).arg(pos.timestamp().toString()).arg(timestampToDateTime(lastTime).toString())));
 		waitingForPosition = false;
 		acquiredPosition();
 		gpsTracker gt;
@@ -182,7 +182,7 @@ void GpsLocation::newPosition(QGeoPositionInfo pos)
 		gt.location = create_location(pos.coordinate().latitude(), pos.coordinate().longitude());
 		addFixToStorage(gt);
 		gpsTracker gtNew = m_trackers.last();
-		qDebug() << "newest fix is now at" << QDateTime().fromMSecsSinceEpoch(gtNew.when - gettimezoneoffset(gtNew.when) * 1000).toString();
+		qDebug() << "newest fix is now at" << timestampToDateTime(gtNew.when - gettimezoneoffset(gtNew.when)).toString();
 	}
 }
 
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index e1329ca26..561dd9213 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -696,12 +696,19 @@ int gettimezoneoffset(timestamp_t when)
 	if (when == 0)
 		dt1 = QDateTime::currentDateTime();
 	else
-		dt1 = QDateTime::fromMSecsSinceEpoch(when * 1000);
+		dt1 = timestampToDateTime(when);
 	dt2 = dt1.toUTC();
 	dt1.setTimeSpec(Qt::UTC);
 	return dt2.secsTo(dt1);
 }
 
+QDateTime timestampToDateTime(timestamp_t when)
+{
+	// Subsurface always uses "local time" as in "whatever was the local time at the location"
+	// so all time stamps have no time zone information and are in UTC
+	return QDateTime::fromMSecsSinceEpoch(1000 * when, Qt::UTC);
+}
+
 QString render_seconds_to_string(int seconds)
 {
 	if (seconds % 60 == 0)
@@ -984,8 +991,7 @@ QString get_trip_date_string(timestamp_t when, int nr, bool getday)
 {
 	struct tm tm;
 	utc_mkdate(when, &tm);
-	QDateTime localTime = QDateTime::fromMSecsSinceEpoch(1000*when,Qt::UTC);
-	localTime.setTimeSpec(Qt::UTC);
+	QDateTime localTime = timestampToDateTime(when);
 
 	QString suffix = " " + gettextFromC::tr("(%n dive(s))", "", nr);
 	if (getday)
diff --git a/core/qthelper.h b/core/qthelper.h
index 8cd31b29c..b0cab8b15 100644
--- a/core/qthelper.h
+++ b/core/qthelper.h
@@ -62,6 +62,7 @@ QString getSubsurfaceDataPath(QString folderToFind);
 QString getPrintingTemplatePathUser();
 QString getPrintingTemplatePathBundle();
 int gettimezoneoffset(timestamp_t when = 0);
+QDateTime timestampToDateTime(timestamp_t when);
 int parseDurationToSeconds(const QString &text);
 int parseLengthToMm(const QString &text);
 int parseTemperatureToMkelvin(const QString &text);
diff --git a/core/subsurface-qt/diveobjecthelper.cpp b/core/subsurface-qt/diveobjecthelper.cpp
index 7c8651507..45cb73868 100644
--- a/core/subsurface-qt/diveobjecthelper.cpp
+++ b/core/subsurface-qt/diveobjecthelper.cpp
@@ -328,15 +328,13 @@ DiveObjectHelperGrantlee::DiveObjectHelperGrantlee(const struct dive *d) :
 
 QString DiveObjectHelper::date() const
 {
-	QDateTime localTime = QDateTime::fromMSecsSinceEpoch(1000 * timestamp, Qt::UTC);
-	localTime.setTimeSpec(Qt::UTC);
+	QDateTime localTime = timestampToDateTime(timestamp);
 	return localTime.date().toString(prefs.date_format_short);
 }
 
 QString DiveObjectHelper::time() const
 {
-	QDateTime localTime = QDateTime::fromMSecsSinceEpoch(1000 * timestamp, Qt::UTC);
-	localTime.setTimeSpec(Qt::UTC);
+	QDateTime localTime = timestampToDateTime(timestamp);
 	return localTime.time().toString(prefs.time_format);
 }