1 | pub(crate) use self::inner::{do_alloc, Allocator, Global}; |
2 | |
3 | // Nightly-case. |
4 | // Use unstable `allocator_api` feature. |
5 | // This is compatible with `allocator-api2` which can be enabled or not. |
6 | // This is used when building for `std`. |
7 | #[cfg (feature = "nightly" )] |
8 | mod inner { |
9 | use crate::alloc::alloc::Layout; |
10 | pub use crate::alloc::alloc::{Allocator, Global}; |
11 | use core::ptr::NonNull; |
12 | |
13 | #[allow (clippy::map_err_ignore)] |
14 | pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> { |
15 | match alloc.allocate(layout) { |
16 | Ok(ptr) => Ok(ptr.as_non_null_ptr()), |
17 | Err(_) => Err(()), |
18 | } |
19 | } |
20 | } |
21 | |
22 | // Basic non-nightly case. |
23 | // This uses `allocator-api2` enabled by default. |
24 | // If any crate enables "nightly" in `allocator-api2`, |
25 | // this will be equivalent to the nightly case, |
26 | // since `allocator_api2::alloc::Allocator` would be re-export of |
27 | // `core::alloc::Allocator`. |
28 | #[cfg (all(not(feature = "nightly" ), feature = "allocator-api2" ))] |
29 | mod inner { |
30 | use crate::alloc::alloc::Layout; |
31 | pub use allocator_api2::alloc::{Allocator, Global}; |
32 | use core::ptr::NonNull; |
33 | |
34 | #[allow (clippy::map_err_ignore)] |
35 | pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> { |
36 | match alloc.allocate(layout) { |
37 | Ok(ptr) => Ok(ptr.cast()), |
38 | Err(_) => Err(()), |
39 | } |
40 | } |
41 | } |
42 | |
43 | // No-defaults case. |
44 | // When building with default-features turned off and |
45 | // neither `nightly` nor `allocator-api2` is enabled, |
46 | // this will be used. |
47 | // Making it impossible to use any custom allocator with collections defined |
48 | // in this crate. |
49 | // Any crate in build-tree can enable `allocator-api2`, |
50 | // or `nightly` without disturbing users that don't want to use it. |
51 | #[cfg (not(any(feature = "nightly" , feature = "allocator-api2" )))] |
52 | mod inner { |
53 | use crate::alloc::alloc::{alloc, dealloc, Layout}; |
54 | use core::ptr::NonNull; |
55 | |
56 | #[allow (clippy::missing_safety_doc)] // not exposed outside of this crate |
57 | pub unsafe trait Allocator { |
58 | fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()>; |
59 | unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout); |
60 | } |
61 | |
62 | #[derive(Copy, Clone)] |
63 | pub struct Global; |
64 | |
65 | unsafe impl Allocator for Global { |
66 | #[inline ] |
67 | fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> { |
68 | unsafe { NonNull::new(alloc(layout)).ok_or(()) } |
69 | } |
70 | #[inline ] |
71 | unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) { |
72 | dealloc(ptr.as_ptr(), layout); |
73 | } |
74 | } |
75 | |
76 | impl Default for Global { |
77 | #[inline ] |
78 | fn default() -> Self { |
79 | Global |
80 | } |
81 | } |
82 | |
83 | pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> { |
84 | alloc.allocate(layout) |
85 | } |
86 | } |
87 | |