Migrate away from winapi 0.2

[repi]

Thanks to the new Cargo nightly -Z timings I saw that our 3.5 min Windows release build was spending 65 seconds building just the old winapi 0.2 crate.

The wall time itself, while very high, is not a major problem as this was a larger from scratch build and lots of cores available, but what the timings clearly showed was that it pushed out a lot of build steps because there were tons of small and big crates that had dependencies on winapi 0.2 directly or indirectly and as such couldn't even start until that had been built.

So want to fully get rid of winapi 0.2 crate in our builds and migrate the crates that we are using to the faster and better winapi 0.3 or, in some cases, remove them.

Current crates that use (directly or indirectly) that uses winapi 0.2:

• iovec:: This is the most important as huge ecosystem depend on this small crate. PR fix filed
• app_dirs: Abandoned crate, switched to app_dirs2 instead and PR fix was merged & published in 7 minutes (!)
• mio: In-progress v0.7 is using latest winapi, v0.6 will stay on winapi 0.2. May just have to wait for v0.7?
• notify: Unmaintained crate, leaf dependency so less important but should find alternative or get it updated. Related PR: Dependencies: Update winapi and remove kernel32-sys notify-rs/notify#217
• wasmer-runtime-core: From page_size. Is there a more modern/maintained equivalent that they can switch to?
• tokio Update to mio 0.7 tokio: update to mio 0.7 tokio-rs/tokio#1190
• Ecosystem upgrade to new tokio 0.3
• winit uses mio 0.6

Once we have those resolved:, we want to allow be able to disallow winapi 0.2 in our projects:

• cargo-deny: Disallow specific versions of crates? cargo-deny#28

[memoryruins]

Noticed similar results trying out -Ztimings on rust-analyzer while on windows http://gistpreview.github.io/?4a6eafbb1f4786c534143c959876f38f cc @matklad

For notify, it directly uses winapi 0.3; however, its dep kernel32-sys pulls in winapi 0.2. I mentioned this to @rep-nop, and they saw that the calls to kernel32-sys could be easily replaced.
I believe they are working on a PR now. notify-rs/notify#217

p.s. notify is currently looking for new maintainers notify-rs/notify#209

[repi]

@memoryruins Awesome thanks! notify is a good library, hope it finds a new good home

[repnop]

notify PR has been merged :)

[crlf0710]

Maybe it's possible to do the semver tricks and make 0.2 crates reexports of 0.3 one

[hrydgard]

Fixing wasmer: wasmerio/wasmer#948

[hrydgard]

The page_size maintainer finally woke up and merged my pull request, so as soon as wasmer upgrades to a new page_size, we'll be down to a single remaining dependency on winapi 0.2! (mio)

Elzair/page_size_rs#1

[repi]

Nice, and mio 0.7-alpha.1 that was released a few days ago has upgraded to winapi 0.3 also. Though likely will take a while for the rest of the stack to use it.

https://tokio.rs/blog/2019-12-mio-v0.7-alpha.1/

[repi]

mio 0.7 has now been released! Just waiting for tokio to update and use it now and then this can finally be closed and we won't need winapi 0.2 anymore!

[repi]

Still waiting for tokio to actually upgrade to mio 0.7. Tracked in tokio-rs/tokio#1190

Also noticed that the old winapi 0.2 doesn't support building for aarch64-pc-windows-msvc (Windows on Arm), so this is a blocker for that.

[Jake-Shadle]

Not that I don't mind getting rid of 0.2, but is Windows Arm actually a relevant target?

[repi]

@Jake-Shadle in general no 😀 but something I'm personally just curious about experimenting with