selection: create global single_selected_trip() function

The DiveListView had a singleSelectedTrip function that
returns the selected trip if exactly one trip is selected.
This could be very slow if numerous non-trip items were
selected, because all the selection indices were back-
translated by the proxy model.

This could make selection changes very slow, because the
MainTab used said function to determine whether it should
show trip or dive data.. Indeed, with a 3500 dive test log,
when selecting all dives in tree mode, the updating of the
TabWidgets is sped up from 130 ms to 5 ms this commit.

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

1 files changed, 2 insertions, 20 deletions

diff --git a/desktop-widgets/divelistview.cpp b/desktop-widgets/divelistview.cpp
index 3e1ec6baa..403165759 100644
--- a/desktop-widgets/divelistview.cpp
+++ b/desktop-widgets/divelistview.cpp
@@ -263,9 +263,8 @@ void DiveListView::rowsInserted(const QModelIndex &parent, int start, int end)
 // Shouldn't the core-layer call us?
 void DiveListView::tripChanged(dive_trip *trip, TripField)
 {
-	// First check if the trip is already selected (and only
-	// this trip, as only then is it displayed). Is so, then do nothing.
-	if (singleSelectedTrip() == trip)
+	// First check if the trip is already selected (and only this trip, as only then is it displayed).
+	if (single_selected_trip() == trip)
 		return;
 
 	unselectDives();
@@ -297,23 +296,6 @@ void DiveListView::unselectDives()
 	selectionModel()->clearSelection();
 }
 
-// This function returns a trip if there is one selected trip or NULL.
-// Returning all selected trips turned out to be too slow.
-dive_trip_t *DiveListView::singleSelectedTrip()
-{
-	dive_trip_t *res = nullptr;
-	for (const QModelIndex &index: selectionModel()->selectedRows()) {
-		if (index.parent().isValid())
-			continue;
-		if (dive_trip_t *trip = index.data(DiveTripModelBase::TRIP_ROLE).value<dive_trip *>()) {
-			if (res)
-				return nullptr; // More than one
-			res = trip;
-		}
-	}
-	return res;
-}
-
 bool DiveListView::eventFilter(QObject *, QEvent *event)
 {
 	if (event->type() != QEvent::KeyPress)