Add TakeCell::get_mut function #2077
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This bypasses the Cell nature of take_cell for situations where you already have access to an `&mut TakeCell`. Similarly to how the corresponding method in `Cell`, `Cell::get_mut` is safe, `TakeCell::get_mut` is entirely safe and requires no new unsafe code to implement. It's made safe by the fact that the returned value is lifetime bound to the takecell itself, not to `'a`. This was useful for an odd interaction with the rubble interface when implementing tock_rubble - it needs to retrieve an `&mut [u8]` multiple times safely, and then also use that buffer as an `&'static mut [u8]` which can be taken out. Thus a `TakeCell`, with the addition of this `get_mut` method, works well. Signed-off-by: David Ross <David.Ross@wdc.com>
hudson-ayers
previously approved these changes
Aug 17, 2020
Signed-off-by: David Ross <David.Ross@wdc.com>
hudson-ayers
approved these changes
Aug 17, 2020
alistair23
approved these changes
Aug 17, 2020
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bors r+ |
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Pull Request Overview
This adds
TakeCell::get_mut, a function with the signaturefn get_mut(&mut self) -> Option<&mut T>. Specifically, it bypasses the Cell nature of take_cell for when you already have access to an&mut TakeCell.This is entirely safe, and works similarly to the corresponding method in
Cell,Cell::get_mut. It's made safe by the fact that the returned value is lifetime bound to the mutable borrow of theTakeCellitself, not to'a- and thus, requires no new unsafe code to implement.This was useful for an odd interaction with the rubble interface when implementing tock_rubble - it needs to retrieve an
&mut [u8]multiple times safely, and then also use that buffer as an&'static mut [u8]which can be taken out. Thus aTakeCell, with the addition of thisget_mutmethod, works well.Testing Strategy
CI
TODO or Help Wanted
Documentation Updated
/docs, or no updates are required.Formatting
make prepush.