Implement Thread::park_timeout

[carllerche]

The implementation is similar to Thread::park

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @brson (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see CONTRIBUTING.md for more information.

[carllerche]

Woops, I am noticing botched docs. Fixed

[brson]

r? @alexcrichton

[alexcrichton]

Shouldn't this be wrapped in while !*guard like the loop above? Otherwise this will block no matter what even if a previous unpark was seen.

[carllerche]

Yes, you are correct. :( I have failed.

[alexcrichton]

Could you also add a test for this? A few simple smoke tests should be fine, but largely just something that calls the functions.

[carllerche]

Done

[alexcrichton]

@bors: r+ 60ba03d

Thanks!

[bors]

⌛ Testing commit 60ba03d with merge fe4340a...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-32-nopt-t, auto-win-32-opt, auto-win-64-nopt-t, auto-win-64-opt