window: Defer stack placement without a buffer

When closing a window and showing a new one, the new one may not be
granted input focus until it gets a buffer on Wayland.

If another window is chosen to receive focus and raised on top of stack,
the newly mapped window is focused but placed underneath that other
window.

Meaning that for Wayland surfaces, we need to defer adding the window to
the stack until we actually get to show it, once we have a buffer
attached.

Rather that checking the windowing backend prior to decide if a window
is stackable or not, introduce a new vfunc is_stackable() which tells
if a window should be added to the stack regardless of the underlying
windowing system.

Also add meta_window_is_in_stack() API rather than checking the stack
position directly (replacing the define WINDOW_IN_STACK only available
in stack.c) and remove a window from the stack only if it is present
in the stack, so that the test in meta_stack_remote() becomes
irrelevant.

https://bugzilla.gnome.org/show_bug.cgi?id=780820

1 files changed, 7 insertions, 0 deletions

diff --git a/src/wayland/meta-window-wayland.c b/src/wayland/meta-window-wayland.c
index f3f0e1688..d5d8e21b0 100644
--- a/src/wayland/meta-window-wayland.c
+++ b/src/wayland/meta-window-wayland.c
@@ -543,6 +543,12 @@ meta_window_wayland_shortcuts_inhibited (MetaWindow         *window,
   return meta_wayland_compositor_is_shortcuts_inhibited (compositor, source);
 }
 
+static gboolean
+meta_window_wayland_is_stackable (MetaWindow *window)
+{
+  return meta_wayland_surface_get_buffer (window->surface) != NULL;
+}
+
 static void
 meta_window_wayland_class_init (MetaWindowWaylandClass *klass)
 {
@@ -562,6 +568,7 @@ meta_window_wayland_class_init (MetaWindowWaylandClass *klass)
   window_class->get_client_pid = meta_window_wayland_get_client_pid;
   window_class->force_restore_shortcuts = meta_window_wayland_force_restore_shortcuts;
   window_class->shortcuts_inhibited = meta_window_wayland_shortcuts_inhibited;
+  window_class->is_stackable = meta_window_wayland_is_stackable;
 }
 
 MetaWindow *