Paint bikeshed for Datum::cast_mut_ptr
#702
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Before 0.5.0 goes gold, paint a bikeshed:
- With `pointer::cast_{const, mut}` stabilizing in 1.65.0,
`Datum::ptr_cast` seems off. Instead, follow the ordering implied by
`cast_mut`, `as_mut`, and `as_mut_ptr`:
cast, mutability, then `_ptr` or rarely `_ref` for pointer-kind.
This gives us `Datum::cast_mut_ptr::<T>` instead.
- `Datum::to_void` was used too rarely to warrant a unique fn,
and `cast_mut_ptr` is more correct in 2 of those cases. Drop it.
This reverts commit c1d9fc9. Not actually unused, it turns out.
| /// True if the datum is equal to the null pointer. | ||
| pub fn is_null(self) -> bool { | ||
| self.0.is_null() | ||
| } | ||
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| /// Assume the datum is a pointer and cast it to point to T. | ||
| pub fn ptr_cast<T>(self) -> *mut T { | ||
| /// It is recommended to explicitly use `datum.cast_mut_ptr::<T>()`. | ||
| pub fn cast_mut_ptr<T>(self) -> *mut T { |
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I wonder if it would be useful to work like Arc::clone() and require the user to do T::cast_mut_ptr(thing)
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I think it's too high an impedance in this case, as normal pointer functions don't require it, and there's a very specific reason Arc requires that for certain functions:
Deref behavior
Arc automatically dereferences to T (via the Deref trait), so you can call T’s methods on a value of type Arc. To avoid name clashes with T’s methods, the methods of Arc itself are associated functions, called using fully qualified syntax:
Note this is not actually required for Arc::clone:
Arc’s implementations of traits like Clone may also be called using fully qualified syntax. Some people prefer to use fully qualified syntax, while others prefer using method-call syntax.
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Is there a way for users to get the old functionality of |
Yes. |
Before 0.5.0 goes gold, paint a bikeshed:
pointer::cast_{const, mut}stabilizing in 1.65.0,Datum::ptr_castseems off. Instead, follow the ordering implied bycast_mut,as_mut, andas_mut_ptr: cast, mutability, then_ptror rarely_reffor pointer-kind. This gives usDatum::cast_mut_ptr::<T>instead.Datum::to_voidwas used too rarely to warrant a unique fn, andcast_mut_ptris more correct in 2 of those cases. Drop it.Also, add some further verbiage about reference safety.