GHOST_WindowWayland.hh File Reference

#include "GHOST_Window.hh"
#include <vector>
#include <wayland-util.h>

Go to the source code of this file.

Classes
class	GHOST_WindowWayland

Macros
#define	USE_EVENT_BACKGROUND_THREAD

Detailed Description

Declaration of GHOST_WindowWayland class.

Definition in file GHOST_WindowWayland.hh.

Macro Definition Documentation

USE_EVENT_BACKGROUND_THREAD

#define USE_EVENT_BACKGROUND_THREAD

Define to workaround for a bug/limitation in WAYLAND, see: #100855 & upstream report: https://gitlab.freedesktop.org/wayland/wayland/-/issues/159

Consume events from WAYLAND in a thread, this is needed because overflowing the event queue causes a fatal error (more than sizeof(wl_buffer.data) at the time of writing).

Solve this using a thread that handles events, locking must be performed as follows:

• Lock #GWL_Display.server_mutex to prevent wl_display_dispatch / wl_display_roundtrip running from multiple threads at once.

  Even though WAYLAND functions that communicate with wl_display_* have their own locks, GHOST functions that communicate with WAYLAND must use this lock to be thread safe.

  Without this reading/writing values such as changing the cursor or setting the window size could conflict with WAYLAND callbacks running in a separate thread. So the server_mutex ensures either GHOST or WAYLAND is manipulating this data, having two WAYLAND callbacks accessing the data at once isn't a problem.

  Warning

  Some operations such as #ContextEGL creation/deletion & swap-buffers may call wl_display_dispatch indirectly, so it's important to take care to lock the server_mutex, before accessing these functions too.

  An unfortunate side-effect of this is care needs to be taken not to call public GHOST functions from each other in situations that would otherwise be supported. As both using a server_mutex results in a dead-lock. In some cases this means the implementation and the public function may need to be split.

• Lock #GWL_Display.timer_mutex when WAYLAND callbacks manipulate timers.
• Lock GWL_Display.events_pending_mutex before manipulating GWL_Display.events_pending.
• Lock GWL_Window.frame_pending_mutex before changing window size & frame settings, this is flushed in GHOST_WindowWayland::pending_actions_handle.

Note

Keep this define as it can be useful to disable threading when troubleshooting issues with events.

Definition at line 58 of file GHOST_WindowWayland.hh.