Add into_inner and get_mut to Mutex and RwLock
#29031
Conversation
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r? @aturon (rust_highfive has picked a reviewer for you, use r? to override) |
| // The following code is like `let Mutex { inner, data } = self`. | ||
| let mut inner = mem::uninitialized::<Box<StaticMutex>>(); | ||
| let mut data = mem::uninitialized::<UnsafeCell<T>>(); | ||
| ptr::copy_nonoverlapping(&self.inner as *const Box<StaticMutex>, |
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Also note that &T coerces to *T
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Done. (re: coercion, just doing &self.inner didn't type check for some reason---maybe some interaction with type inference.)
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Other than the ptr::read stuff, this looks great! Really thorough. I'm not really qualified to review this kind of code, though. |
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Thanks @gankro! I changed to |
alexcrichton
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T-libs-api
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Local (full) |
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@aturon mentioned in a different bug he is going to be unavailable. r? @alexcrichton |
brson
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This shouldn't close #28968 if it is using it as a tracking issue. |
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The libs team talked about this today, and the conclusion is that this is good to go. The changes we'd like to see, however, are:
let (a, b) = {
let Mutex { ref a, ref b } = self; // note exhaustive match
(ptr::read(a), ptr::read(b))
};
mem::forget(self);
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@huonw Good point, I edited the description to not close the issue. @alexcrichton That all makes sense, I'll do all of that when I get back from work, thanks! |
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@alexcrichton I implemented everything you asked for, please take a look. Thanks! |
| /// | ||
| /// If another user of this mutex panicked while holding the mutex, then | ||
| /// this call will return an error instead. | ||
| #[inline] |
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Ah as one final piece, could these #[inline] annotations be left out? These are pretty hefty functions and the inline shouldn't be needed anyway as a result of the generic parameter on Mutex
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@alexcrichton Done and squashed. Don't feel strongly, but I had added The fact that it has a type param doesn't quite imply |
cristicbz
changed the title
into_inner and get_mut to sync::Mutexinto_inner and get_mut to Mutex and RwLock
The implementation for `into_inner` was a bit more complex than I had hoped for---is there any simpler, less unsafe way of getting around the fact that one can't move out of a `Drop` struct? See #28968 and rust-lang/rfcs#1269 .
The implementation for
into_innerwas a bit more complex than I had hoped for---is there any simpler, less unsafe way of getting around the fact that one can't move out of aDropstruct?See #28968 and rust-lang/rfcs#1269 .