1#[cfg(test)]
2pub(crate) use self::inner::AllocError;
3pub(crate) use self::inner::{do_alloc, Allocator, Global};
4
5// Nightly-case.
6// Use unstable `allocator_api` feature.
7// This is compatible with `allocator-api2` which can be enabled or not.
8// This is used when building for `std`.
9#[cfg(feature = "nightly")]
10mod inner {
11 #[cfg(test)]
12 pub use crate::alloc::alloc::AllocError;
13 use crate::alloc::alloc::Layout;
14 pub use crate::alloc::alloc::{Allocator, Global};
15 use core::ptr::NonNull;
16
17 #[allow(clippy::map_err_ignore)]
18 pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
19 match alloc.allocate(layout) {
20 Ok(ptr: NonNull<[u8]>) => Ok(ptr.as_non_null_ptr()),
21 Err(_) => Err(()),
22 }
23 }
24}
25
26// Basic non-nightly case.
27// This uses `allocator-api2` enabled by default.
28// If any crate enables "nightly" in `allocator-api2`,
29// this will be equivalent to the nightly case,
30// since `allocator_api2::alloc::Allocator` would be re-export of
31// `core::alloc::Allocator`.
32#[cfg(all(not(feature = "nightly"), feature = "allocator-api2"))]
33mod inner {
34 use crate::alloc::alloc::Layout;
35 #[cfg(test)]
36 pub use allocator_api2::alloc::AllocError;
37 pub use allocator_api2::alloc::{Allocator, Global};
38 use core::ptr::NonNull;
39
40 #[allow(clippy::map_err_ignore)]
41 pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
42 match alloc.allocate(layout) {
43 Ok(ptr) => Ok(ptr.cast()),
44 Err(_) => Err(()),
45 }
46 }
47}
48
49// No-defaults case.
50// When building with default-features turned off and
51// neither `nightly` nor `allocator-api2` is enabled,
52// this will be used.
53// Making it impossible to use any custom allocator with collections defined
54// in this crate.
55// Any crate in build-tree can enable `allocator-api2`,
56// or `nightly` without disturbing users that don't want to use it.
57#[cfg(not(any(feature = "nightly", feature = "allocator-api2")))]
58mod inner {
59 use crate::alloc::alloc::{alloc, dealloc, Layout};
60 use core::ptr::NonNull;
61
62 #[allow(clippy::missing_safety_doc)] // not exposed outside of this crate
63 pub unsafe trait Allocator {
64 fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()>;
65 unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout);
66 }
67
68 #[derive(Copy, Clone)]
69 pub struct Global;
70
71 unsafe impl Allocator for Global {
72 #[inline]
73 fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> {
74 unsafe { NonNull::new(alloc(layout)).ok_or(()) }
75 }
76 #[inline]
77 unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
78 dealloc(ptr.as_ptr(), layout);
79 }
80 }
81
82 impl Default for Global {
83 #[inline]
84 fn default() -> Self {
85 Global
86 }
87 }
88
89 pub(crate) fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
90 alloc.allocate(layout)
91 }
92}
93