Re: [9front] Thoughts on Wayland?

[Dave MacFarlane <driusan@driusan.net>]

On August 5, 2024 4:26:10 a.m. GMT+09:00, Willow Liquorice <willow@howhill.com> wrote:
>Hello again 9front,
>
>(Warning: long email is long)
>
>I've been leafing through the Wayland protocol, comparing it to rio and /dev/draw. To me, a system that could speak Wayland sounds much more compatible with the wider software ecosystem.
>
>Has there been much thought put into Wayland in 9front? I'd poke around in the list archives, but I haven't figured out how to 9P on my Linux machine yet.
>
>Here are my thoughts:
>
>1. The Wayland compositor and clients talk to each other over a Unix domain socket. I'm guessing Plan 9 doesn't have those (and doesn't want them) as there's nothing in sys/man on the subject. Could pipe(3) do the trick?
>
>2. Shared memory (where wl_buffers are stored) is achieved by passing a file descriptor from the client to the compositor, which the compositor mmaps as needed.
>
>If I understand correctly, that already sounds pretty plan9-y, though I'm not sure whether you could then treat the file *like* shared memory under 9front. Again, couldn't find any references to "mmap" in the manuals, so I guess there's no direct analogue. Could you achieve the same (or similar) effect with a ramfs?
>
>3. protocol/wayland.xml is apparently used to generate all of the function prototypes you need to speak Wayland. If the underlying components (shared memory and a domain socket lookalike) work, making a Wayland library for Plan 9 (Way 9?) *might* boil down to a paint-by-numbers exercise.
>
>Wayland's been around a while, so maybe none of these observations are new. I don't know! I'm a novice.
>
>Regards,
>	Willow
>

What is your goal?

If you want to learn about /dev/draw and Wayland trying to port Wayland for yourself is an ambitious goal but you would learn a lot.

If you want to improve the architecture replacing a Plan 9 solution for graphics with a Linux one is of dubious value.

If you want to make it easier to port software you're trying to run before you walk. Anything that uses Wayland almost certainly needs all kinds of other Linux-specific libraries or modern C extensions or LLVM or etc and you'd get more value working on APE* and starting with something more concrete (a specific, preferrably small, program you'd like to port.)

* I am not sure if 9front is really interested in a more complete APE, having just removed ape/diff.. I'd suggest reaching out to the Harvey people since this idea is more up their lane but I think Harvey is dead. 

- Dave