rocket-auth-login VS rust

There is https://github.com/vishusandy/rocket-auth-login IIRC. It's "third-party" (e.g. not by the rocket team). I haven't used it really (just tinkered around with it). I am also no expert when it comes down to authentication. But I do remember taking a look at the code. It looked all right.

"Experimental feature gate proposal interoperable_abi #105586"

As an engineer having spent most of 2022 learning the Rust language, I was a little worried about the no_std side of embedded systems programming.

The reason we are providing our own hasher is that the default one relies on the sys crate which is platform dependent. Our platform being unsupported, the associated implementation either does nothing or fails.

Further down that GitHub issue, it mentions the problem has been fixed:

* https://github.com/rust-lang/rust/issues/71871#issuecomment-...

* https://github.com/rust-lang/rust/pull/79998

Weirdly though, there's another issue (opened prior) that's ongoing and seems to indicate things aren't fixed after all:

* https://github.com/rustwasm/team/issues/291

>wasm32-unknown-unknown has an ABI incompatibility which means you cannot interoperate between C compiled to Wasm and Rust compiled to Wasm.

Since I was surprised to learn this, and to save everyone else the search, it's https://github.com/rust-lang/rust/issues/71871

The reasoning behind this is that if there are no more strong references but weak references still exist, the weak references need to refer back to the same memory, which won't be possible if the memory has already been freed. A bit counter intuitive and I got amazed when I first learned it. If you're interested in the details, check out the source code.

There's no magic behind Stdout. It is just like writing bytes into files and any types that implement std::io::Write playground. RawTerminal is merely a wrapper for Stdout, and Stdout is an empty struct that implements io::Write that calls a libc function that displays the written bytes to our terminal.

You may find the discussion on issue #53639 (Consider deprecation of UB-happy static mut) from about this point onwards to be illuminating. Specifically, the topic of ISRs and synchronisation on embedded systems is discussed, with alternatives, and it's stated that UnsafeCell is so fundamental that any non-zero-cost to it is considered a bug in the compiler:

That's why MutexGuard is not Send. See https://github.com/rust-lang/rust/issues/23465 from 2015.

There is a tracking issue to implement a lint for this in the compiler: https://github.com/rust-lang/rust/issues/83310