Add FromBytes::zero_and_get_bytes
#2369
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Closes #2318 gherrit-pr-id: I38a568578de67f067fab936d17ba57332c6cdfed
joshlf
commented
Feb 20, 2025
| /// | ||
| /// # Examples | ||
| /// | ||
| /// TODO |
| // - `data` is valid for reads and writes of `len` bytes: | ||
| // - `data` refers to a block of `len` bytes within a single allocated | ||
| // object by invariant on `&mut self` | ||
| // - TODO: Others? https://doc.rust-lang.org/std/ptr/index.html#safety |
| /// | ||
| /// TODO | ||
| #[inline] | ||
| fn zero_and_get_bytes(&mut self) -> &mut [u8] { |
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My thoughts on the name:
zero_and_get_bytesis a good and clear name, though its length is right on that border of being verbose.mutcould be mentioned but is not necessary when the namezeroimplies mutation.fn zero(&mut self)onFromZeroscould yield&[u8]of all zeros, and that could be given the same name. I struggle to consider a situation where it's practically useful to have access to an all-zeros&[u8]with the same address as some&mut T, so 🤷🏻♀️
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## v0.8.x #2369 +/- ##
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- Coverage 87.47% 87.09% -0.39%
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Files 16 16
Lines 6182 6209 +27
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Hits 5408 5408
- Misses 774 801 +27 ☔ View full report in Codecov by Sentry. |
kupiakos
reviewed
Feb 21, 2025
| /// This permits accessing the bytes of a type which may not implement | ||
| /// [`IntoBytes`] by first zeroing any padding bytes which would be unsound | ||
| /// to expose via [`IntoBytes::as_bytes`]. | ||
| /// |
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Maybe it's worth mentioning why this has to be on FromBytes and can't be on FromZeros? It's obvious to me but it could help solidify the concepts of the library to new users.
| let data: *mut Self = self; | ||
| let data = data.cast::<u8>(); | ||
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| // SAFETY: |
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Perhaps FromBytes::read_from_io could be refactored to use this in this PR, keeping the total number of unsafe the same and simplifying its implementation further. It still needs the one unsafe at the end.
| // duration of its lifetime. | ||
| // - By invariant on `&mut self`, the referent is not larger than | ||
| // `isize::MAX` bytes, and the referent does not wrap around the | ||
| // address space |
| /// | ||
| /// TODO | ||
| #[inline] | ||
| fn zero_and_get_bytes(&mut self) -> &mut [u8] { |
There was a problem hiding this comment.
My thoughts on the name:
zero_and_get_bytesis a good and clear name, though its length is right on that border of being verbose.mutcould be mentioned but is not necessary when the namezeroimplies mutation.fn zero(&mut self)onFromZeroscould yield&[u8]of all zeros, and that could be given the same name. I struggle to consider a situation where it's practically useful to have access to an all-zeros&[u8]with the same address as some&mut T, so 🤷🏻♀️
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Closes #2318
gherrit-pr-id: I38a568578de67f067fab936d17ba57332c6cdfed