mago_allocator/
copy.rs

1use crate::arena::Arena;
2
3/// A deep copy of a value into an arena, rebinding every internal reference.
4///
5/// Implementors copy all of their arena-resident data (byte slices, nested
6/// references, slices of children) into the given arena, so the output is
7/// self-contained: it stays valid after the arena the input lived in is
8/// dropped or reset.
9///
10/// ```
11/// use mago_allocator::prelude::*;
12///
13/// struct Name<'arena> {
14///     value: &'arena [u8],
15/// }
16///
17/// impl CopyInto for Name<'_> {
18///     type Output<'arena> = Name<'arena>;
19///
20///     fn copy_into<'arena, A>(&self, arena: &'arena A) -> Self::Output<'arena>
21///     where
22///         A: Arena,
23///     {
24///         Name { value: arena.alloc_slice_copy(self.value) }
25///     }
26/// }
27///
28/// let source = LocalArena::new();
29/// let target = LocalArena::new();
30///
31/// let name = Name { value: source.alloc_slice_copy(b"App\\Collection") };
32/// let copied = name.copy_into(&target);
33/// drop(source);
34///
35/// assert_eq!(copied.value, b"App\\Collection");
36/// ```
37pub trait CopyInto {
38    type Output<'arena>: 'arena;
39
40    fn copy_into<'arena, A>(&self, arena: &'arena A) -> Self::Output<'arena>
41    where
42        A: Arena;
43}
44
45/// Copies `value` into the arena and returns a reference to the copy.
46#[must_use]
47#[inline]
48pub fn copy_ref_into<'arena, T, A>(value: &T, arena: &'arena A) -> &'arena T::Output<'arena>
49where
50    T: CopyInto,
51    A: Arena,
52{
53    arena.alloc(value.copy_into(arena))
54}
55
56/// Copies every element of `values` into the arena as a new slice.
57#[must_use]
58#[inline]
59pub fn copy_slice_into<'arena, T, A>(values: &[T], arena: &'arena A) -> &'arena [T::Output<'arena>]
60where
61    T: CopyInto,
62    A: Arena,
63{
64    arena.alloc_slice_fill_iter(values.iter().map(|value| value.copy_into(arena)))
65}
66
67macro_rules! trivial_copy_into {
68    ($ty:ty) => {
69        impl CopyInto for $ty {
70            type Output<'arena> = $ty;
71
72            fn copy_into<'arena, A>(&self, _arena: &'arena A) -> Self::Output<'arena>
73            where
74                A: Arena,
75            {
76                *self
77            }
78        }
79    };
80    ($($ty:ty),+) => {
81        $(trivial_copy_into!($ty);)+
82    };
83}
84
85trivial_copy_into!((), bool, u8, u16, u32, u64, usize, i8, i16, i32, i64, isize, f32, f64);
mago_allocator/copy.rs

mago_allocator/
copy.rs
