canvas-view: change action states only when the value differs

Commit bb884cb6 introduced the faulty behavior where
NautilusCanvasView keeps scrolling back to the first
selected item when selecting multiple items.

Backtracing it, it was found out that the icon view
was changing the "sort" state when selecting items,
even if nothing actually changed, which triggers the
sort action changed handler. The handler by itself
was doing the right job by revealing the selection,
and the issue was caused by calling it unnecessarily.

Since we may have to update the action states for other
reasons besidse real sort change, we must change the
action state only when it makes sense, i.e. only when
the states really change.

https://bugzilla.gnome.org/show_bug.cgi?id=748265

1 files changed, 28 insertions, 6 deletions

diff --git a/src/nautilus-canvas-view.c b/src/nautilus-canvas-view.c
index b7f4edbd1..b6fe026ad 100644
--- a/src/nautilus-canvas-view.c
+++ b/src/nautilus-canvas-view.c
@@ -1061,13 +1061,35 @@ nautilus_canvas_view_update_actions_state (NautilusView *view)
 
 	view_action_group = nautilus_view_get_action_group (view);
 	if (nautilus_canvas_view_supports_auto_layout (canvas_view)) {
-		g_action_group_change_action_state (view_action_group,
-						    "reversed-order",
-						    g_variant_new_boolean (NAUTILUS_CANVAS_VIEW (view)->details->sort_reversed));
+		GVariant *sort_state;
+		GVariant *reversed_state;
+
+		/* When we change the sort action state, even using the same value, it triggers
+		 * the sort action changed handler, which reveals the selection, since we expect
+		 * the selection to be visible when the user changes the sort order. But we may
+		 * need to update the actions state for others reason than an actual sort change,
+		 * so we need to prevent to trigger the sort action changed handler for those cases.
+		 * To achieve this, check if the action state value actually changed before setting
+		 * it. The same happens to the reversed-order state.
+		 */
+		sort_state = g_action_group_get_action_state (view_action_group, "sort");
+		reversed_state = g_action_group_get_action_state (view_action_group, "reversed-order");
+
+		if (NAUTILUS_CANVAS_VIEW (view)->details->sort_reversed != g_variant_get_boolean (reversed_state)) {
+			g_action_group_change_action_state (view_action_group,
+							    "reversed-order",
+							    g_variant_new_boolean (NAUTILUS_CANVAS_VIEW (view)->details->sort_reversed));
+		}
+
+		if (g_strcmp0 (g_variant_get_string (sort_state, NULL),
+                               NAUTILUS_CANVAS_VIEW (view)->details->sort->action_target_name) != 0) {
+			g_action_group_change_action_state (view_action_group,
+                                                            "sort",
+                                                             g_variant_new_string (NAUTILUS_CANVAS_VIEW (view)->details->sort->action_target_name));
+		}
 
-		g_action_group_change_action_state (view_action_group,
-						    "sort",
-						    g_variant_new_string (NAUTILUS_CANVAS_VIEW (view)->details->sort->action_target_name));
+		g_variant_unref (reversed_state);
+		g_variant_unref (sort_state);
 	}
 
 	action = g_action_map_lookup_action (G_ACTION_MAP (view_action_group), "keep-aligned");