focus stack and next/prev toplevel keybinds

include/focus.h

@@ -3,3 +3,5 @@
 #include "types.h"
 
 void focus_toplevel(struct absinthe_toplevel *toplevel);
+void focus_next(struct absinthe_server *server);
+void focus_prev(struct absinthe_server *server);

include/types.h

@@ -54,7 +54,6 @@ struct absinthe_server {
     struct wlr_xdg_shell *xdg_shell;
     struct wl_listener new_xdg_toplevel;
     struct wl_listener new_xdg_popup;
-    struct wl_list toplevels;
     struct wlr_xdg_decoration_manager_v1 *xdg_decoration_mgr;
     struct wl_listener new_xdg_decoration;
 
@@ -78,6 +77,9 @@ struct absinthe_server {
     uint32_t grab_x, grab_y;
     enum absinthe_cursor_resize_corner cursor_resize_corner;
 
+    struct wl_list toplevels;
+    struct wl_list focus_stack;
+
     struct absinthe_output *focused_output;
     struct wl_list outputs;
     struct wl_listener new_output;
@@ -100,6 +102,7 @@ struct absinthe_output {
 
 struct absinthe_toplevel {
     struct wl_list link;
+    struct wl_list flink; // for focus stack
     struct absinthe_server *server;
     struct absinthe_output *output;
     struct wlr_scene_tree *scene_tree;

src/absinthe-toplevel.c

@@ -27,7 +27,7 @@ struct absinthe_toplevel *absinthe_toplevel_at(struct absinthe_server *server, d
         return tree->node.data;
         break;
     case WLR_SCENE_NODE_RECT:
-        return node->data;        
+        return node->data;
         break;
     default:
         return NULL;
@@ -66,7 +66,7 @@ void absinthe_toplevel_set_fullscreen(struct absinthe_toplevel *toplevel, bool f
     } else {
         toplevel->geometry = toplevel->prev_geometry;
         toplevel->border_width = ABSINTHE_WINDOW_BORDER_WIDTH;
-        absinthe_toplevel_set_size(toplevel, toplevel->geometry.width, toplevel->geometry.height);        
+        absinthe_toplevel_set_size(toplevel, toplevel->geometry.width, toplevel->geometry.height);
     }
 }
 

src/focus.c

@@ -1,4 +1,5 @@
 #include <wayland-server-core.h>
+#include <wlr/util/log.h>
 
 #include "types.h"
 #include "absinthe-toplevel.h"
@@ -26,11 +27,45 @@ void focus_toplevel(struct absinthe_toplevel *toplevel)
 
     struct wlr_keyboard *keyboard = wlr_seat_get_keyboard(seat);
     wlr_scene_node_raise_to_top(&toplevel->scene_tree->node);
-    wl_list_remove(&toplevel->link);
+    wl_list_remove(&toplevel->flink);
-    wl_list_insert(&server->toplevels, &toplevel->link);
+    wl_list_insert(&server->focus_stack, &toplevel->flink);
     wlr_xdg_toplevel_set_activated(toplevel->xdg_toplevel, true);
     absinthe_toplevel_set_border_color(toplevel, focused_border_color);
 
     if (keyboard)
         wlr_seat_keyboard_notify_enter(seat, surface, keyboard->keycodes, keyboard->num_keycodes, &keyboard->modifiers);
 }
+
+static struct absinthe_toplevel *focus_get_topmost(struct absinthe_server *server)
+{
+    struct absinthe_toplevel *toplevel;
+    wl_list_for_each(toplevel, &server->focus_stack, flink) {
+        if (toplevel)
+            return toplevel;
+    }
+    return NULL;
+}
+
+void focus_next(struct absinthe_server *server)
+{
+    struct absinthe_toplevel *toplevel = focus_get_topmost(server);
+    struct absinthe_toplevel *next;
+    wl_list_for_each(next, &toplevel->link, link) {
+        if (&next->link == &toplevel->server->toplevels)
+            continue;
+        break;
+    }
+    focus_toplevel(next);
+}
+
+void focus_prev(struct absinthe_server *server)
+{
+    struct absinthe_toplevel *toplevel = focus_get_topmost(server);
+    struct absinthe_toplevel *prev;
+    wl_list_for_each_reverse(prev, &toplevel->link, link) {
+        if (&prev->link == &toplevel->server->toplevels)
+            continue;
+        break;
+    }
+    focus_toplevel(prev);
+}

src/keyboard.c

@@ -8,6 +8,7 @@
 
 #include "types.h"
 #include "absinthe-toplevel.h"
+#include "focus.h"
 
 void keyboard_handle_modifiers(struct wl_listener *listener, void *data)
 {
@@ -19,6 +20,18 @@ void keyboard_handle_modifiers(struct wl_listener *listener, void *data)
 
 static bool keyboard_handle_keybind(struct absinthe_server *server, xkb_keysym_t keysym)
 {
+    struct wlr_surface *surface;
+    struct wlr_xdg_toplevel *xdg_toplevel;
+    struct absinthe_toplevel *toplevel;
+
+    surface = server->seat->pointer_state.focused_surface;
+
+    if (surface)
+        xdg_toplevel = wlr_xdg_toplevel_try_from_wlr_surface(surface);
+
+    if (xdg_toplevel)
+        toplevel = xdg_toplevel->base->data;
+
     switch (keysym) {
     case XKB_KEY_Escape:
         wl_display_terminate(server->display);
@@ -28,21 +41,15 @@ static bool keyboard_handle_keybind(struct absinthe_server *server, xkb_keysym_t
             execl("/bin/sh", "sh", "-c", "alacritty", NULL);
         break;
     case XKB_KEY_f:
-        struct wlr_surface *surface = server->seat->pointer_state.focused_surface;
-
-        if (!surface)
-            break;
-        
-        struct wlr_xdg_toplevel *xdg_toplevel = wlr_xdg_toplevel_try_from_wlr_surface(surface);
-
-        if (!xdg_toplevel)
-            break;
-
-        struct absinthe_toplevel *toplevel = xdg_toplevel->base->data;
-
         if (toplevel)
             absinthe_toplevel_set_fullscreen(toplevel, !toplevel->fullscreen);
         break;
+    case XKB_KEY_j:
+        focus_next(server);
+        break;
+    case XKB_KEY_k:
+        focus_prev(server);
+        break;
     default:
         return false;
     }

src/main.c

@@ -89,6 +89,8 @@ int main(int argc, char **argv)
     server.scene_layout = wlr_scene_attach_output_layout(server.scene, server.output_layout);
 
     wl_list_init(&server.toplevels);
+    wl_list_init(&server.focus_stack);
+
     server.xdg_shell = wlr_xdg_shell_create(server.display, 3);
     server.new_xdg_toplevel.notify = server_new_xdg_toplevel;
     wl_signal_add(&server.xdg_shell->events.new_toplevel, &server.new_xdg_toplevel);

src/xdg-toplevel.c

@@ -42,14 +42,15 @@ void xdg_toplevel_map(struct wl_listener *listener, void *data)
     }
 
     toplevel->border_width = ABSINTHE_WINDOW_BORDER_WIDTH;
-    
+
     absinthe_toplevel_set_border_color(toplevel, unfocused_border_color);
     absinthe_toplevel_update_borders_geometry(toplevel);
 
     toplevel->output = toplevel->server->focused_output;
     toplevel->fullscreen = false;
-    
+
     wl_list_insert(&toplevel->server->toplevels, &toplevel->link);
+    wl_list_insert(&toplevel->server->focus_stack, &toplevel->flink);
 }
 
 void xdg_toplevel_unmap(struct wl_listener *listener, void *data)