An attempt to collect several proposals of rust-lang/wg-allocators into a MVP.
This crate is WIP, requires a nightly compiler, and is designed to replace the alloc crate. However, this is not completely possible as crate, as some compiler features are not possible for crates.
Alloc traitThe first thing to notice is, that [Alloc] was renamed to [AllocRef] in order to show that they are typically
implemented for a reference or smart pointer or ZST, not directly for the type that actually holds the allocator’s
state.
Issue: rust-lang/wg-allocators#8
[AllocRef] was split up into [AllocRef], [DeallocRef], and [ReallocRef] to make more flexible allocators
possible.
Issue: rust-lang/wg-allocators#9
The allocators has to be associated with [BuildAllocRef]. It is related to the allocator traits similar how
[BuildHasher] is related to [Hasher]. Although the signatures are different, it makes an even more flexible
allocator design possible.
Issue: rust-lang/wg-allocators#12
Added an associative error type to [AllocRef]. Besides adding the possibility of returning additional information on
allocation failure, it's also possible to split the usage of the [AllocRef] into a fallible and an infallible case.
Personally I think this is a pretty big deal, as kernel programmer can rely on allocation, which will never fail. If
an allocation can fail, only a try_*_in method may be available. To maintain backwards compatibility, [AbortAlloc]
was introduced. [AbortAlloc] wraps another allocator, but aborts on OOM thus AbortAlloc<Global> may be used as
default allocator for [Box] or Vec. To realize this, [AbortAlloc] implements AllocRef<Error=!>.
Issue: rust-lang/wg-allocators#23
The new layout type [NonZeroLayout] was introduced. Currently, implementors of [Alloc] can chose to allow
zero-sized allocation so in a generic context it's impossible to rely on this, so banning zero-sized allocation is a
possible step to prevent this. This also removes unsafe from [AllocRef::alloc] and [AllocRef::alloc_zeroed], and
unlocks the possibility to move the extension API like alloc_array into a separate trait.
Issue: rust-lang/wg-allocators#16
Support reallocating to a different alignment.
Issue: rust-lang/wg-allocators#5
Add support for _zeroed buffer in Vec.
Issue: rust-lang/wg-allocators#32
[Box]struct
T: Copy for Fn-traits as it's not possible for downstream crates.[RawVec]
Vec]String]Alloc-WG is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.