rework CastPtr, CastConstPtr, BoxCastPtr, ArcCastPtr
#353
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cpu
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Oct 13, 2023
cpu
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Oct 13, 2023
cpu
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Oct 13, 2023
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I like Castable a lot!
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This commit reworks the existing `CastPtr`, `CastConstPtr`, `BoxCastPtr`, and `ArcCastPtr` traits into a new `Castable` trait with an associated `Ownership`, constrained to be a type implementing the new `OwnershipMarker` trait. Three implementations of this `OwnershipMarker` trait are offered: `OwnershipBox`, `OwnershipArc` and `OwnershipRef`. The net result is that the type system is now able to enforce our invariant that a single `Castable` type can't be cast to a pointer of more than one type of ownership (e.g. both an `Arc` and a `Box`). We always implement a distinct type per-ownership model. Along the way crate-internal documentation for the traits and associated free-standing helper `fs`s were reworked for clarity/consistency.
Previously the helper macros in `src/lib.rs` were marked `macro_export`, making them part of the public API. Since these were meant to be crate internal, we also annotated the macros as `doc(hidden)` to avoid them appearing in the API docs. I suspect this was done before `pub(crate)` visibility was an option. This commit removes the `macro_export` and `doc(hidden)` attributes and uses a `pub(crate)` re-export to make the macros available to crate-internal users without making them part of the public API. Along the way this uncovered that the `try_mut_slice!` macro wasn't being used anywhere and so it is removed outright.
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jsha
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Thanks for all your help along the way 🙇 |
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rework CastPtr, CastConstPtr, BoxCastPtr, ArcCastPtr
This commit reworks the existing
CastPtr,CastConstPtr,BoxCastPtr, andArcCastPtrtraits into a newCastabletrait with an associatedOwnership, constrained to be a type implementing the newOwnershipMarkertrait. Three implementations of thisOwnershipMarkertrait are offered:OwnershipBox,OwnershipArcandOwnershipRef.The net result is that the type system is now able to enforce our invariant that a single
Castabletype can't be cast to a pointer of more than one type of ownership (e.g. both anArcand aBox). ImplementingCastablefor the same type with differentOwnership's orRustType's will be rejected by the compiler as a conflicting trait implementation. We always implement a distinct type per-ownership model, and per rust type.Along the way crate-internal documentation for the traits and associated free-standing helper
fss were reworked for clarity/consistency.Resolves #349
lib: remove pub export of macros
Previously the helper macros in
src/lib.rswere markedmacro_export, making them part of the public API. Since these weremeant to be crate internal, we also annotated the macros as
doc(hidden)to avoid them appearing in the API docs. I suspect this was done beforepub(crate)visibility was an option.This commit removes the
macro_exportanddoc(hidden)attributes and uses apub(crate)re-export to make the macros available to crate-internal users without making them part of the public API.This also uncovered that the
try_mut_slice!macro wasn't being used anywhere and so it is removed outright.