capnproto-rust VS UnrealEngine

The only hurdle I have is that while the documentation is extensive it is a little confusing in places and mainly focuses on C++ and the C++ RPC system which is a little different to the Rust code. There are Rust examples in the official repo which I will try and leverage here.

capnproto-rust is the official Rust implementation.

Hi, you seem to know a bit about Sanakirja!

It stores 4kb blobs, right? Does Pijul first parses the data (copying it to other allocations), or uses the data as is? I mean, there are some libraries like cap'n'proto[0] and rkyv[1] that can directly use the file contents as an in-memory data structure, I was wondering if Pijul did anything like that.

I mean, is this btree page [2] stored exactly like this on disk, and does Pijul exploits that to avoid further copying data?

(I guess there's a trouble with compression there: to decompress you really need to write in another buffer)

Also, is the I/O done with something that prevent userspace copies like mmap or io_uring, or does it eventually calls read() to copy the data to its own buffer?

I want to build something like Sanakirja, but with those features, so I'm wondering if there's any overlap.

[0] https://github.com/capnproto/capnproto-rust

[1] https://github.com/rkyv/rkyv

[2] https://docs.rs/sanakirja-core/latest/sanakirja_core/btree/p...

Visual Studio has a related annoying habit when navigating the call stack (the caller's scope is considered closed if the callee is syntactically its tail) so I wonder whether this workaround would be useful for it as well.

See also this comment in the Unreal Engine code about putting a nop in before as well: https://github.com/EpicGames/UnrealEngine/blob/26677ca1b3c97...

    // Q: Why is there a __nop() before __debugbreak()?

> you can still use it with smart pointers provided by any other library

Is the point of having a kitchen-sink library like this not that you dont have to reach for a 3rdparty library for things that you need 'all the time'?

Certainly, not everyone needs it.

...but, not everyone needs threads either. Not everyone needs an http server; and yet, if you have an application framework that provides them, when you do need them, it saves you reaching for yet-another-dependency.

Was that no the point from the beginning?

unique_ptr is a fundamental primitive for many, as you see from some other frameworks (1), and implementation is not always either a) trivial, or b) as simple as 'just use std::unique_ptr'.

This does seem like a very opinionated decision with reasonably unclear justification.

[1] - eg. https://github.com/EpicGames/UnrealEngine/blob/release/Engin..., https://github.com/electronicarts/EASTL/blob/master/include/...

It is not publicly available. If you click on this link you get a 404 page: https://github.com/EpicGames/UnrealEngine You actually have to go and subscribe, agree to their terms, and then you get to view the source code. It happens to be free, but it is by no means "public".

https://github.com/EpicGames/UnrealEngine/tree/5.2.0-preview-2 For anyone wondering

Like I said before, you have the fixed code here (commit: 23937975).

Before you can access the repository at https://github.com/EpicGames/UnrealEngine, you must: be an Unreal Engine subscriber. have a GitHub account. have associated your GitHub account with your Unreal Engine account as described on the UE4 on GitHub page.

What you need to do is follow this link and diff my file with Epic's file. You can grab settings that I have from mine and plop them into a custom one for yours. Just be mindful if you're developing in VR for what settings you bring over.

Originally it was going to be NetworkPrediction (need to be signed into a github account with Unreal Engine access for that link to work), but since David Ratti left Epic that died and they stopped working on it. (I didn't know it was dead, that was the CMC replacement I was referring to)

Found this while looking through UE commits