oneshot: document UnsafeCell invariants #4229
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Having just looked at #4226, this is very helpful. |
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Requesting a review from Carl as I believe he wrote most of the original code here. |
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Darksonn
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Nov 15, 2021
hawkw
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Nov 15, 2021
Depends on #4226 ## Motivation Currently, the safety invariants and synchronization strategy used in `tokio::sync::oneshot` are not particularly obvious, especially to a new reader. It would be nice to better document this code to make these invariants clearer. ## Solution This branch adds `SAFETY:` comments to the `oneshot` channel implementation. In particular, I've focused on documenting the invariants around when the inner `UnsafeCell` that stores the value can be accessed by the sender and receiver sides of the channel. I still want to take a closer look at when the waker cells can be set, and I'd like to add more documentation there in a follow-up branch. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
hawkw
added a commit
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this pull request
Nov 15, 2021
Depends on #4226 ## Motivation Currently, the safety invariants and synchronization strategy used in `tokio::sync::oneshot` are not particularly obvious, especially to a new reader. It would be nice to better document this code to make these invariants clearer. ## Solution This branch adds `SAFETY:` comments to the `oneshot` channel implementation. In particular, I've focused on documenting the invariants around when the inner `UnsafeCell` that stores the value can be accessed by the sender and receiver sides of the channel. I still want to take a closer look at when the waker cells can be set, and I'd like to add more documentation there in a follow-up branch. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
hawkw
added a commit
that referenced
this pull request
Nov 16, 2021
Depends on #4226 ## Motivation Currently, the safety invariants and synchronization strategy used in `tokio::sync::oneshot` are not particularly obvious, especially to a new reader. It would be nice to better document this code to make these invariants clearer. ## Solution This branch adds `SAFETY:` comments to the `oneshot` channel implementation. In particular, I've focused on documenting the invariants around when the inner `UnsafeCell` that stores the value can be accessed by the sender and receiver sides of the channel. I still want to take a closer look at when the waker cells can be set, and I'd like to add more documentation there in a follow-up branch. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
hawkw
added a commit
that referenced
this pull request
Nov 16, 2021
Depends on #4226 ## Motivation Currently, the safety invariants and synchronization strategy used in `tokio::sync::oneshot` are not particularly obvious, especially to a new reader. It would be nice to better document this code to make these invariants clearer. ## Solution This branch adds `SAFETY:` comments to the `oneshot` channel implementation. In particular, I've focused on documenting the invariants around when the inner `UnsafeCell` that stores the value can be accessed by the sender and receiver sides of the channel. I still want to take a closer look at when the waker cells can be set, and I'd like to add more documentation there in a follow-up branch. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
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Depends on #4226
Motivation
Currently, the safety invariants and synchronization strategy used in
tokio::sync::oneshotare not particularly obvious, especially to a newreader. It would be nice to better document this code to make these
invariants clearer.
Solution
This branch adds
SAFETY:comments to theoneshotchannelimplementation. In particular, I've focused on documenting the
invariants around when the inner
UnsafeCellthat stores the value canbe accessed by the sender and receiver sides of the channel.
I still want to take a closer look at when the waker cells can be set,
and I'd like to add more documentation there in a follow-up branch.