Support openbox style "cycle window"

We still use alt-F2, but it now feels like alt-tab does.

labwc.h

@@ -68,6 +68,8 @@ struct server {
 	struct wl_listener request_cursor;
 	struct wl_listener request_set_selection;
 	struct wl_list keyboards;
+
+	/* cursor interactive */
 	enum cursor_mode cursor_mode;
 	struct view *grabbed_view;
 	double grab_x, grab_y;
@@ -139,19 +141,15 @@ void xwl_surface_configure(struct wl_listener *listener, void *data);
 void xwl_surface_new(struct wl_listener *listener, void *data);
 
 bool view_want_deco(struct view *view);
-void view_focus_last_toplevel(struct server *server);
 void view_focus(struct view *view);
-void view_focus_next_toplevel(struct view *current);
 void begin_interactive(struct view *view, enum cursor_mode mode,
 		       uint32_t edges);
-bool is_toplevel(struct view *view);
+struct view *view_front_toplevel(struct server *server);
+struct view *next_toplevel(struct view *current);
 struct view *view_at(struct server *server, double lx, double ly,
 		     struct wlr_surface **surface, double *sx, double *sy,
 		     int *view_area);
 
-/* TODO: try to refactor to remove from header file */
-struct view *first_toplevel(struct server *server);
-
 void server_new_input(struct wl_listener *listener, void *data);
 void seat_request_cursor(struct wl_listener *listener, void *data);
 void seat_request_set_selection(struct wl_listener *listener, void *data);

server.c

@@ -1,5 +1,8 @@
 #include "labwc.h"
 
+static bool in_alt_tab_mode;
+static struct view *alt_tab_view;
+
 static void keyboard_handle_modifiers(struct wl_listener *listener, void *data)
 {
 	/* This event is raised when a modifier key, such as shift or alt, is
@@ -33,7 +36,9 @@ static bool handle_keybinding(struct server *server, xkb_keysym_t sym)
 		break;
 	case XKB_KEY_F1:
 	case XKB_KEY_F2:
-		view_focus_last_toplevel(server);
+		in_alt_tab_mode = true;
+		alt_tab_view = next_toplevel(view_front_toplevel(server));
+		fprintf(stderr, "alt_tab_view=%p\n", (void *)alt_tab_view);
 		break;
 	case XKB_KEY_F3:
 		if (fork() == 0) {
@@ -41,8 +46,8 @@ static bool handle_keybinding(struct server *server, xkb_keysym_t sym)
 		}
 		break;
 	case XKB_KEY_F6:
-		begin_interactive(first_toplevel(server), TINYWL_CURSOR_MOVE,
-				  0);
+		begin_interactive(view_front_toplevel(server),
+				  TINYWL_CURSOR_MOVE, 0);
 		break;
 	case XKB_KEY_F12:
 		dbg_show_views(server);
@@ -71,6 +76,23 @@ static void keyboard_handle_key(struct wl_listener *listener, void *data)
 	bool handled = false;
 	uint32_t modifiers =
 		wlr_keyboard_get_modifiers(keyboard->device->keyboard);
+
+	if (in_alt_tab_mode) {
+		if ((syms[0] == XKB_KEY_Alt_L) &&
+		    event->state == WLR_KEY_RELEASED) {
+			/* end cycle */
+			in_alt_tab_mode = false;
+			view_focus(alt_tab_view);
+		} else if (event->state == WLR_KEY_PRESSED) {
+			/* cycle to next */
+			alt_tab_view = next_toplevel(alt_tab_view);
+			fprintf(stderr, "alt_tab_view=%p\n",
+				(void *)alt_tab_view);
+			return;
+		}
+	}
+
+	/* Handle compositor key bindings */
 	if ((modifiers & WLR_MODIFIER_ALT) && event->state == WLR_KEY_PRESSED) {
 		/* If alt is held down and this button was _pressed_, we attempt
 		 * to process it as a compositor keybinding. */
@@ -78,7 +100,6 @@ static void keyboard_handle_key(struct wl_listener *listener, void *data)
 			handled = handle_keybinding(server, syms[i]);
 		}
 	}
-
 	if (!handled) {
 		/* Otherwise, we pass it along to the client. */
 		wlr_seat_set_keyboard(seat, keyboard->device);

view.c

@@ -1,6 +1,6 @@
 #include "labwc.h"
 
-bool is_toplevel(struct view *view)
+static bool is_toplevel(struct view *view)
 {
 	switch (view->type) {
 	case LAB_XDG_SHELL_VIEW:
@@ -11,61 +11,18 @@ bool is_toplevel(struct view *view)
 	return false;
 }
 
-struct view *first_toplevel(struct server *server)
+bool view_want_deco(struct view *view)
 {
-	struct view *view;
-
-	wl_list_for_each (view, &server->views, link) {
-		if (!view->been_mapped) {
-			continue;
-		}
-		if (is_toplevel(view)) {
-			return view;
-		}
-	}
-	fprintf(stderr, "warn: found no toplevel view (%s)\n", __func__);
-	return NULL;
-}
-
-static struct view *last_toplevel(struct server *server)
-{
-	struct view *view;
-
-	wl_list_for_each_reverse (view, &server->views, link) {
-		if (!view->been_mapped)
-			continue;
-		if (is_toplevel(view))
-			return view;
-	}
-	/* no top-level view */
-	return NULL;
-}
-
-void view_focus_last_toplevel(struct server *server)
-{
-	/* TODO: write view_nr_toplevel_views() */
-	if (wl_list_length(&server->views) < 2)
-		return;
-	struct view *view = last_toplevel(server);
-	view_focus(view);
-}
-
-static struct view *next_toplevel(struct view *current)
-{
-	struct view *tmp = current;
-
-	do {
-		tmp = wl_container_of(tmp->link.next, tmp, link);
-	} while (!tmp->been_mapped || !is_toplevel(tmp));
-	return tmp;
-}
-
-/* Original function name - suggest we keep it */
-void view_focus_next_toplevel(struct view *current)
-{
-	struct view *view;
-	view = next_toplevel(current);
-	view_focus(view);
+	if (view->type != LAB_XWAYLAND_VIEW)
+		return false;
+	if (!is_toplevel(view))
+		return false;
+	if (view->xwayland_surface->override_redirect)
+		return false;
+	if (view->xwayland_surface->decorations !=
+	    WLR_XWAYLAND_SURFACE_DECORATIONS_ALL)
+		return false;
+	return true;
 }
 
 static void move_to_front(struct view *view)
@@ -128,20 +85,6 @@ void view_focus(struct view *view)
 				       &keyboard->modifiers);
 }
 
-bool view_want_deco(struct view *view)
-{
-	if (view->type != LAB_XWAYLAND_VIEW)
-		return false;
-	if (!is_toplevel(view))
-		return false;
-	if (view->xwayland_surface->override_redirect)
-		return false;
-	if (view->xwayland_surface->decorations !=
-	    WLR_XWAYLAND_SURFACE_DECORATIONS_ALL)
-		return false;
-	return true;
-}
-
 void begin_interactive(struct view *view, enum cursor_mode mode, uint32_t edges)
 {
 	/* This function sets up an interactive move or resize operation, where
@@ -184,6 +127,28 @@ void begin_interactive(struct view *view, enum cursor_mode mode, uint32_t edges)
 	}
 }
 
+struct view *view_front_toplevel(struct server *server)
+{
+	struct view *view;
+	wl_list_for_each (view, &server->views, link) {
+		if (!view->been_mapped)
+			continue;
+		if (is_toplevel(view))
+			return view;
+	}
+	return NULL;
+}
+
+struct view *next_toplevel(struct view *current)
+{
+	/* FIXME: write nr_toplevels() */
+	struct view *view = current;
+	do {
+		view = wl_container_of(view->link.next, view, link);
+	} while (!view->been_mapped || !is_toplevel(view));
+	return view;
+}
+
 static bool _view_at(struct view *view, double lx, double ly,
 		     struct wlr_surface **surface, double *sx, double *sy)
 {

xdg.c

@@ -61,7 +61,7 @@ void xdg_surface_unmap(struct wl_listener *listener, void *data)
 {
 	struct view *view = wl_container_of(listener, view, unmap);
 	view->mapped = false;
-	view_focus_next_toplevel(view);
+	view_focus(next_toplevel(view));
 }
 
 void xdg_surface_destroy(struct wl_listener *listener, void *data)

xwl.c

@@ -49,7 +49,12 @@ void xwl_surface_unmap(struct wl_listener *listener, void *data)
 {
 	struct view *view = wl_container_of(listener, view, unmap);
 	view->mapped = false;
-	view_focus_next_toplevel(view);
+	/*
+	 * Note that if 'view' is not a toplevel view, the 'front' toplevel view
+	 * will be focussed on; but if 'view' is a toplevel view, the 'next'
+	 * will be focussed on.
+	 */
+	view_focus(next_toplevel(view));
 }
 
 void xwl_surface_destroy(struct wl_listener *listener, void *data)