GDK has a lock to mark critical sections inside the backends.
Additionally, code that would re-enter into the GTK main loop was
supposed to hold the lock.
Back in the Good Old Days™ this was guaranteed to kind of work only on
the X11 backend, and would cause a neat explosion on any other GDK
backend.
During GTK+ 3.x we deprecated the API to enter and leave the critical
sections, and now we can remove all the internal uses of the lock, since
external API that uses GTK+ 4.x won't be able to hold the GDK lock.
https://bugzilla.gnome.org/show_bug.cgi?id=793124
There is no need to have every application log a warning when the
Wayland display server goes away, and we are using _exit instead of
exit elsewhere.
This is also what the X11 backend does (see gdk_x_io_error).
https://bugzilla.gnome.org/show_bug.cgi?id=745289
Aborting the application makes it look like an application bug, when
it is the expected thing to do when the Wayland display server goes
way. eg., when the user logs out. The log level is also demoted to
avoid a storm of warnings in the log from all applications whenever
this happens.
This is also what the X11 backend does (see gdk_x_io_error).
https://bugzilla.gnome.org/show_bug.cgi?id=783047
This is required for proper integration with any other library/application that
may perform wayland API calls and poll() the wayland fd from multiple threads.
Using wl_display_dispatch{_queue}() is thread-safe if not mixed with custom
poll() usage, which GSource/GMainContext does.
Essentially, the problem is that multiple threads polling and reading
the same fd is extremely racy. Use the wayland provided API for allowing
concurrent access to the wayland display fd.
See the wayland man pages for wl_display_prepare_read(),
wl_display_cancel_read() and wl_display_read_events() for more details.
https://bugzilla.gnome.org/show_bug.cgi?id=763852
When the Wayland compositor vanishes, all applications connected will
receive a SIGPIPE as soon as they try to use wl_display_dispatch().
Do not use g_error() to terminate the applications when this occurs,
g_error() means an error in the application while here it's not truly
the case.
Use g_warning() and exit() instead.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
https://bugzilla.gnome.org/show_bug.cgi?id=745289
If a motion event handler (or other handler running from the flush-events
phase of the frame clock) recursed the main loop then flushing wouldn't
complete until after the recursed main loop returned, and various aspects
of the state would get out of sync.
To fix this, change flushing of the event queue to simply mark events as
ready to flush, and let normal event delivery handle the rest.
https://bugzilla.gnome.org/show_bug.cgi?id=705176
If we don't dispatch the pending events then we can enter poll with events
still requiring to be processed and which can then lead to us deadlocking
there.
We can get G_IO_HUP and G_IO_IN at the same time, if the compositor writes
data to us and then closes our connection. Make sure that we dispatch events
always if we have G_IO_IN and then error out if we get G_IO_HUP after that.
When events are paused, we should not return TRUE from prepare() or check().
GTK+ handles this for events that are already in the GTK+ queue, but
we also need suppress checks for events that are in the system queue - if we
return TRUE indicating that there are events in the system queue, then we'll
call dispatch(), and do nothing. The event source will spin, and will never
run the other phases of the paint clock.
https://bugzilla.gnome.org/show_bug.cgi?id=694274
