Most resources must not be NULL. Make it so callers need to check for
NULL explicitly. This makes it clearer in the handlers code that the
NULL wl_resource case needs to be handled, and allows callers to make a
difference between a NULL wl_resource and an inert resource.
Some globals are static and it doesn't make sense to destroy them before
the wl_display. For instance, wl_compositor should be created before the
display is started and shouldn't be destroyed.
For these globals, we can simplify the code by removing the destructor
and stop keeping track of wl_resources (these will be destroyed with the
wl_display by libwayland).
From the xdg-shell specification:
If the parent is unmapped then its children are managed as
though the parent of the now-unmapped parent has become the
parent of this surface. If no parent exists for the now-unmapped
parent then the children are managed as though they have no
parent surface.
Since the fullscreen request may be made before the toplevel's surface
is mapped, the requested fullscreen output needs to be stored so it
can be retrieved on map (along with the existing fullscreen property).
This commit makes the required changes for wlr_xdg_toplevel.
It doesn't make sense to keep popups opened when unmapped. We also need to do
so in wlr_xdg_popup_destroy so that popups are destroyed in the correct order.
ie. don't destroy surface->toplevel on xdg_toplevel destroy. Instead do this on
xdg_surface destroy.
This allows compositors to add toplevel listeners when the surface appears and
remove them when the surface is destroyed.
It is common to want to iterate an xdg-surface's popups separately from
the toplevel and subsurfaces. For example, popups are typically rendered
on top of most other surfaces.
wlr_xdg_surface_for_each_surface continues to iterate both surfaces and
popups to maintain backwards compatibility.
popups have a link in parent's surface->popups list and needs
to be freed before:
==6902==ERROR: AddressSanitizer: heap-use-after-free on address 0x6120001a0300 at pc 0x7fc1447acb50 bp 0x7fffd396e680 sp 0x7fffd396e670
WRITE of size 8 at 0x6120001a0300 thread T0
#0 0x7fc1447acb4f in wl_list_remove ../util/signal.c:55
#1 0x7fc14477d206 in destroy_xdg_popup_v6 ../types/xdg_shell_v6/wlr_xdg_popup_v6.c:162
#2 0x7fc1447816e0 in destroy_xdg_surface_v6 ../types/xdg_shell_v6/wlr_xdg_surface_v6.c:108
#3 0x7fc144a1c025 in destroy_resource src/wayland-server.c:688
#4 0x7fc144a1c091 in wl_resource_destroy src/wayland-server.c:705
#5 0x7fc14477fd6f in xdg_client_v6_handle_resource_destroy ../types/xdg_shell_v6/wlr_xdg_shell_v6.c:72
#6 0x7fc144a1c025 in destroy_resource src/wayland-server.c:688
#7 0x7fc144a20851 (/lib64/libwayland-server.so.0+0xc851)
#8 0x7fc144a20d92 (/lib64/libwayland-server.so.0+0xcd92)
#9 0x7fc144a1c140 in wl_client_destroy src/wayland-server.c:847
#10 0x7fc144a1c21c in destroy_client_with_error src/wayland-server.c:307
#11 0x7fc144a1c21c in wl_client_connection_data src/wayland-server.c:330
#12 0x7fc144a1df01 in wl_event_loop_dispatch src/event-loop.c:641
#13 0x7fc144a1c601 in wl_display_run src/wayland-server.c:1260
#14 0x40a2f4 in main ../sway/main.c:433
#15 0x7fc143ef718a in __libc_start_main ../csu/libc-start.c:308
#16 0x40b749 in _start (/opt/wayland/bin/sway+0x40b749)
0x6120001a0300 is located 64 bytes inside of 264-byte region [0x6120001a02c0,0x6120001a03c8)
freed by thread T0 here:
#0 0x7fc14690d880 in __interceptor_free (/lib64/libasan.so.5+0xee880)
#1 0x7fc1447acce8 in wlr_signal_emit_safe ../util/signal.c:29
#2 0x7fc1447a3cac in surface_handle_resource_destroy ../types/wlr_surface.c:576
#3 0x7fc144a1c025 in destroy_resource src/wayland-server.c:688
previously allocated by thread T0 here:
#0 0x7fc14690de50 in calloc (/lib64/libasan.so.5+0xeee50)
#1 0x7fc144781d38 in create_xdg_surface_v6 ../types/xdg_shell_v6/wlr_xdg_surface_v6.c:415
#2 0x7fc14147503d in ffi_call_unix64 (/lib64/libffi.so.6+0x603d)
Alternative would be to have popups listen to the parent's surface
destroy event and remove themselves from the list at this point OR on
their own destroy, whichever happens first, but that seems more
complicated for little benefit.
