From 7b232d9f65ca9a6d54bd85a9b8923decd12a0f6a Mon Sep 17 00:00:00 2001
From: Carlos Garnacho <carlosg@gnome.org>
Date: Wed, 15 Nov 2023 00:26:35 +0100
Subject: [PATCH] wayland: Keep track of the "input focus" on MetaWaylandSeat

This is the unified focus (key, IM, pads, ...) for the focus window.
Just like MetaWaylandPointer and others keep track of the "current"
surface, this is the "current" surface for those (not necessarily
the focused surface, e.g. in the case of compositor grabs).

Since this unified focus will exist regardless of keyboard
capabilities (e.g. even if just for "logical" focus like IM/clipboard
that does not depend on input devices), it does not make sense
to trigger a focus sync on keyboard capability changes, the focus
is staying the same, we however need to focus the keyboard interface
to the already existing focus when the capability is enabled.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3511>
---
 src/wayland/meta-wayland-keyboard.c |  4 ++++
 src/wayland/meta-wayland-seat.c     | 36 ++++++++++++++++++++++-------
 src/wayland/meta-wayland-seat.h     |  3 +++
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/src/wayland/meta-wayland-keyboard.c b/src/wayland/meta-wayland-keyboard.c
index 706991828..5403f8c04 100644
--- a/src/wayland/meta-wayland-keyboard.c
+++ b/src/wayland/meta-wayland-keyboard.c
@@ -529,6 +529,8 @@ static const MetaWaylandKeyboardGrabInterface default_keyboard_grab_interface =
 void
 meta_wayland_keyboard_enable (MetaWaylandKeyboard *keyboard)
 {
+  MetaWaylandInputDevice *input_device = META_WAYLAND_INPUT_DEVICE (keyboard);
+  MetaWaylandSeat *seat = meta_wayland_input_device_get_seat (input_device);
   MetaBackend *backend = backend_from_keyboard (keyboard);
   ClutterBackend *clutter_backend = clutter_get_default_backend ();
 
@@ -549,6 +551,8 @@ meta_wayland_keyboard_enable (MetaWaylandKeyboard *keyboard)
                     G_CALLBACK (on_kbd_a11y_mask_changed), keyboard);
 
   meta_wayland_keyboard_take_keymap (keyboard, meta_backend_get_keymap (backend));
+
+  meta_wayland_keyboard_set_focus (keyboard, seat->input_focus);
 }
 
 static void
diff --git a/src/wayland/meta-wayland-seat.c b/src/wayland/meta-wayland-seat.c
index 07439f22b..ee91ef1c3 100644
--- a/src/wayland/meta-wayland-seat.c
+++ b/src/wayland/meta-wayland-seat.c
@@ -155,14 +155,7 @@ meta_wayland_seat_set_capabilities (MetaWaylandSeat *seat,
     meta_wayland_pointer_disable (seat->pointer);
 
   if (CAPABILITY_ENABLED (prev_flags, flags, WL_SEAT_CAPABILITY_KEYBOARD))
-    {
-      MetaWaylandCompositor *compositor =
-        meta_wayland_seat_get_compositor (seat);
-
-      meta_wayland_keyboard_enable (seat->keyboard);
-
-      meta_wayland_compositor_sync_focus (compositor);
-    }
+    meta_wayland_keyboard_enable (seat->keyboard);
   else if (CAPABILITY_DISABLED (prev_flags, flags, WL_SEAT_CAPABILITY_KEYBOARD))
     meta_wayland_keyboard_disable (seat->keyboard);
 
@@ -409,6 +402,13 @@ meta_wayland_seat_handle_event (MetaWaylandSeat *seat,
   return FALSE;
 }
 
+static void
+input_focus_destroyed (MetaWaylandSurface *surface,
+                       MetaWaylandSeat    *seat)
+{
+  meta_wayland_seat_set_input_focus (seat, NULL);
+}
+
 void
 meta_wayland_seat_set_input_focus (MetaWaylandSeat    *seat,
                                    MetaWaylandSurface *surface)
@@ -416,6 +416,26 @@ meta_wayland_seat_set_input_focus (MetaWaylandSeat    *seat,
   MetaWaylandCompositor *compositor = meta_wayland_seat_get_compositor (seat);
   MetaWaylandTabletSeat *tablet_seat;
 
+  if (seat->input_focus == surface)
+    return;
+
+  if (seat->input_focus)
+    {
+      g_clear_signal_handler (&seat->input_focus_destroy_id,
+                              seat->input_focus);
+      seat->input_focus = NULL;
+    }
+
+  seat->input_focus = surface;
+
+  if (surface)
+    {
+      seat->input_focus_destroy_id =
+        g_signal_connect (surface, "destroy",
+                          G_CALLBACK (input_focus_destroyed),
+                          seat);
+    }
+
   if (meta_wayland_seat_has_keyboard (seat))
     {
       meta_wayland_keyboard_set_focus (seat->keyboard, surface);
diff --git a/src/wayland/meta-wayland-seat.h b/src/wayland/meta-wayland-seat.h
index ba2cf5644..df2e92dda 100644
--- a/src/wayland/meta-wayland-seat.h
+++ b/src/wayland/meta-wayland-seat.h
@@ -48,6 +48,9 @@ struct _MetaWaylandSeat
 
   MetaWaylandTextInput *text_input;
 
+  MetaWaylandSurface *input_focus;
+  gulong input_focus_destroy_id;
+
   guint capabilities;
 };