action: Implement shift to go backwards in OSD

Signed-off-by: Joshua Ashton <joshua@froggi.es>

include/labwc.h

@@ -386,12 +386,19 @@ void foreign_toplevel_handle_create(struct view *view);
 void desktop_raise_view(struct view *view);
 void desktop_focus_and_activate_view(struct seat *seat, struct view *view);
 
+enum lab_cycle_dir
+{
+	LAB_CYCLE_DIR_NONE,
+	LAB_CYCLE_DIR_FORWARD,
+	LAB_CYCLE_DIR_BACKWARD,
+};
+
 /**
  * desktop_cycle_view - return view to 'cycle' to
  * @current: reference point for finding next view to cycle to
  * Note: If !current, the server->views second focusable view is returned
  */
-struct view *desktop_cycle_view(struct server *server, struct view *current);
+struct view *desktop_cycle_view(struct server *server, struct view *current, enum lab_cycle_dir dir);
 struct view *desktop_focused_view(struct server *server);
 void desktop_focus_topmost_mapped_view(struct server *server);
 bool isfocusable(struct view *view);

src/action.c

@@ -46,7 +46,7 @@ action(struct server *server, const char *action, const char *command)
 		view_snap_to_edge(desktop_focused_view(server), command);
 	} else if (!strcasecmp(action, "NextWindow")) {
 		server->cycle_view =
-			desktop_cycle_view(server, server->cycle_view);
+			desktop_cycle_view(server, server->cycle_view, LAB_CYCLE_DIR_NONE);
 		osd_update(server);
 	} else if (!strcasecmp(action, "Reconfigure")) {
 		spawn_async_no_shell("killall -SIGHUP labwc");

src/desktop.c

@@ -149,18 +149,23 @@ first_view(struct server *server)
 }
 
 struct view *
-desktop_cycle_view(struct server *server, struct view *current)
+desktop_cycle_view(struct server *server, struct view *current, enum lab_cycle_dir dir)
 {
 	if (!has_focusable_view(&server->views)) {
 		return NULL;
 	}
 
 	struct view *view = current ? current : first_view(server);
-
+	if (dir == LAB_CYCLE_DIR_FORWARD) {
 		/* Replacement for wl_list_for_each_from() */
 		do {
 			view = wl_container_of(view->link.next, view, link);
 		} while (&view->link == &server->views || !isfocusable(view));
+	} else if (dir == LAB_CYCLE_DIR_BACKWARD) {
+		do {
+			view = wl_container_of(view->link.prev, view, link);
+		} while (&view->link == &server->views || !isfocusable(view));
+	}
 	damage_all_outputs(server);
 	return view;
 }

src/keyboard.c

@@ -73,6 +73,18 @@ handle_keybinding(struct server *server, uint32_t modifiers, xkb_keysym_t sym)
 	return false;
 }
 
+static bool is_modifier_key(xkb_keysym_t sym)
+{
+	return sym == XKB_KEY_Shift_L ||
+		   sym == XKB_KEY_Shift_R ||
+		   sym == XKB_KEY_Alt_L ||
+		   sym == XKB_KEY_Alt_R ||
+		   sym == XKB_KEY_Control_L ||
+		   sym == XKB_KEY_Control_R ||
+		   sym == XKB_KEY_Super_L ||
+		   sym == XKB_KEY_Super_R;
+}
+
 static bool
 handle_compositor_keybindings(struct wl_listener *listener,
 		struct wlr_event_keyboard_key *event)
@@ -96,11 +108,21 @@ handle_compositor_keybindings(struct wl_listener *listener,
 		damage_all_outputs(server);
 		if (event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
 			/* cycle to next */
+			bool backwards = modifiers & WLR_MODIFIER_SHIFT;
+			/* ignore if this is a modifier key being pressed */
+			bool ignore = false;
+			for (int i = 0; i < nsyms; i++) {
+				ignore |= is_modifier_key(syms[i]);
+			}
+
+			if (!ignore) {
 				server->cycle_view =
-				desktop_cycle_view(server, server->cycle_view);
+					desktop_cycle_view(server, server->cycle_view,
+						backwards ? LAB_CYCLE_DIR_BACKWARD : LAB_CYCLE_DIR_FORWARD);
 				osd_update(server);
 				damage_all_outputs(server);
 			}
+		}
 		/* don't send any key events to clients when osd onscreen */
 		return true;
 	}