Rename event: correctly replace event with new one

I don't like that the event structure includes the variable length array.
That really makes it a pain to change the name of an event (on the flip
side, freeing events is easier I guess).

Anyway, to correctly rename an event we need to actually remove the event
from the correct dc and then add a new event with the new name. The
previous code was insane (it only worked if the new name was of smaller or
equal length, otherwise it had a beautiful buffer overflow).

And of course we need to do this both for the current_dive and the
displayed_dive.

Fixes #616

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

dive.c

@@ -75,6 +75,29 @@ void remove_event(struct event* event)
 	}
 }
 
+/* since the name is an array as part of the structure (how silly is that?) we
+ * have to actually remove the existing event and replace it with a new one.
+ * WARNING, WARNING... this may end up freeing event in case that event is indeed
+ * WARNING, WARNING... part of this divecomputer on this dive! */
+void update_event_name(struct dive *d, struct event* event, char *name)
+{
+	if (!d || !event)
+		return;
+	struct divecomputer *dc = get_dive_dc(d, dc_number);
+	if (!dc)
+		return;
+	struct event **removep = &dc->events;
+	struct event *remove;
+	while ((*removep)->next && !same_event(*removep, event))
+		removep = &(*removep)->next;
+	if (!same_event(*removep, event))
+		return;
+	remove = *removep;
+	*removep = (*removep)->next;
+	add_event(dc, event->time.seconds, event->type, event->flags, event->value, name);
+	free(remove);
+}
+
 /* this returns a pointer to static variable - so use it right away after calling */
 struct gasmix *get_gasmix_from_event(struct event *ev)
 {

dive.h

@@ -624,6 +624,7 @@ extern void fill_default_cylinder(cylinder_t *cyl);
 extern void add_gas_switch_event(struct dive *dive, struct divecomputer *dc, int time, int idx);
 extern void add_event(struct divecomputer *dc, int time, int type, int flags, int value, const char *name);
 extern void remove_event(struct event *event);
+extern void update_event_name(struct dive *d, struct event* event, char *name);
 extern void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *mean, int *duration);
 extern int get_cylinder_index(struct dive *dive, struct event *ev);
 extern int nr_cylinders(struct dive *dive);

qt-ui/profile/profilewidget2.cpp

@@ -1093,10 +1093,14 @@ void ProfileWidget2::editName()
 			lengthWarning.exec();
 			return;
 		}
-		strcpy(event->name, newName.toUtf8());
+		// order is important! first update the current dive (by matching the unchanged event),
-		remember_event(event->name);
+		// then update the displayed dive (as event is part of the events on displayed dive
+		// and will be freed as part of changing the name!
+		update_event_name(current_dive, event, newName.toUtf8().data());
+		update_event_name(&displayed_dive, event, newName.toUtf8().data());
+		mark_divelist_changed(true);
+		replot();
 	}
-	replot();
 }
 
 void ProfileWidget2::disconnectTemporaryConnections()