Map: don't fully reset model on selection change

When changing the selection the MapLocationModel was reset.
This lead to crashes on Qt-5.9 which are due to QML accessing
data that was freed during model reset. This putative Qt bug
doesn't happen on newer Qt versions. At least Qt-5.12 is known
to work.

Instead of fighting the bug, let's simply not reset the model
but send a dataChanged() for every element of the MapLocationModel.

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

7 files changed, 25 insertions, 1 deletions

diff --git a/desktop-widgets/mainwindow.cpp b/desktop-widgets/mainwindow.cpp
index 2a215b1b7..004d5823d 100644
--- a/desktop-widgets/mainwindow.cpp
+++ b/desktop-widgets/mainwindow.cpp
@@ -464,7 +464,7 @@ void MainWindow::selectionChanged()
 		configureToolbar();
 		enableDisableOtherDCsActions();
 	}
-	MapWidget::instance()->reload();
+	MapWidget::instance()->selectionChanged();
 }
 
 void MainWindow::on_actionNew_triggered()
diff --git a/desktop-widgets/mapwidget.cpp b/desktop-widgets/mapwidget.cpp
index 27c30686f..376a29998 100644
--- a/desktop-widgets/mapwidget.cpp
+++ b/desktop-widgets/mapwidget.cpp
@@ -84,6 +84,13 @@ bool MapWidget::editMode() const
 	return isReady && m_mapHelper->editMode();
 }
 
+void MapWidget::selectionChanged()
+{
+	CHECK_IS_READY_RETURN_VOID();
+	m_mapHelper->selectionChanged();
+	m_mapHelper->centerOnSelectedDiveSite();
+}
+
 void MapWidget::selectedDivesChanged(const QList<int> &list)
 {
 	CHECK_IS_READY_RETURN_VOID();
diff --git a/desktop-widgets/mapwidget.h b/desktop-widgets/mapwidget.h
index bc9303166..9e05ce48f 100644
--- a/desktop-widgets/mapwidget.h
+++ b/desktop-widgets/mapwidget.h
@@ -23,6 +23,7 @@ public:
 
 	static MapWidget *instance();
 	void reload();
+	void selectionChanged();
 	bool editMode() const;
 
 public slots:
diff --git a/map-widget/qmlmapwidgethelper.cpp b/map-widget/qmlmapwidgethelper.cpp
index feaccdbef..02bfa78a2 100644
--- a/map-widget/qmlmapwidgethelper.cpp
+++ b/map-widget/qmlmapwidgethelper.cpp
@@ -113,6 +113,11 @@ void MapWidgetHelper::reloadMapLocations()
 	m_mapLocationModel->reload(m_map);
 }
 
+void MapWidgetHelper::selectionChanged()
+{
+	m_mapLocationModel->selectionChanged();
+}
+
 void MapWidgetHelper::selectedLocationChanged(struct dive_site *ds_in)
 {
 	int idx;
diff --git a/map-widget/qmlmapwidgethelper.h b/map-widget/qmlmapwidgethelper.h
index af469193e..046cb4ce1 100644
--- a/map-widget/qmlmapwidgethelper.h
+++ b/map-widget/qmlmapwidgethelper.h
@@ -36,6 +36,7 @@ public:
 	Q_INVOKABLE void updateCurrentDiveSiteCoordinatesFromMap(struct dive_site *ds, QGeoCoordinate coord);
 	Q_INVOKABLE void selectVisibleLocations();
 	Q_INVOKABLE void selectedLocationChanged(struct dive_site *ds);
+	void selectionChanged();
 	QString pluginObject();
 	bool editMode() const;
 
diff --git a/qt-models/maplocationmodel.cpp b/qt-models/maplocationmodel.cpp
index 0fe86f596..ea7d4f098 100644
--- a/qt-models/maplocationmodel.cpp
+++ b/qt-models/maplocationmodel.cpp
@@ -150,6 +150,15 @@ static bool hasSelectedDive(const dive_site *ds)
 			   [] (const dive *d) { return d->selected; });
 }
 
+void MapLocationModel::selectionChanged()
+{
+	if (m_mapLocations.isEmpty())
+		return;
+	for(MapLocation *m: m_mapLocations)
+		m->m_selected = m_selectedDs.contains(m->divesite());
+	emit dataChanged(createIndex(0, 0), createIndex(m_mapLocations.size() - 1, 0));
+}
+
 void MapLocationModel::reload(QObject *map)
 {
 	beginResetModel();
diff --git a/qt-models/maplocationmodel.h b/qt-models/maplocationmodel.h
index 8cec08818..25ae159bd 100644
--- a/qt-models/maplocationmodel.h
+++ b/qt-models/maplocationmodel.h
@@ -67,6 +67,7 @@ public:
 	void add(MapLocation *);
 	// If map is not null, it will be used to place new dive sites without GPS location at the center of the map
 	void reload(QObject *map);
+	void selectionChanged();
 	MapLocation *getMapLocation(const struct dive_site *ds);
 	const QVector<dive_site *> &selectedDs() const;
 	Q_INVOKABLE void setSelected(struct dive_site *ds);