diff options
Diffstat (limited to 'crates/ra_hir/src/arena.rs')
-rw-r--r-- | crates/ra_hir/src/arena.rs | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/crates/ra_hir/src/arena.rs b/crates/ra_hir/src/arena.rs new file mode 100644 index 000000000..a752ec0c1 --- /dev/null +++ b/crates/ra_hir/src/arena.rs | |||
@@ -0,0 +1,66 @@ | |||
1 | //! A simple id-based arena, similar to https://github.com/fitzgen/id-arena. | ||
2 | //! We use our own version for more compact id's and to allow inherent impls | ||
3 | //! on Ids. | ||
4 | |||
5 | use std::{ | ||
6 | fmt, | ||
7 | hash::{Hash, Hasher}, | ||
8 | marker::PhantomData, | ||
9 | }; | ||
10 | |||
11 | pub(crate) struct Id<T> { | ||
12 | idx: u32, | ||
13 | _ty: PhantomData<fn() -> T>, | ||
14 | } | ||
15 | |||
16 | impl<T> fmt::Debug for Id<T> { | ||
17 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | ||
18 | f.debug_tuple("Id").field(&self.idx).finish() | ||
19 | } | ||
20 | } | ||
21 | impl<T> Copy for Id<T> {} | ||
22 | impl<T> Clone for Id<T> { | ||
23 | fn clone(&self) -> Id<T> { | ||
24 | *self | ||
25 | } | ||
26 | } | ||
27 | |||
28 | impl<T> PartialEq for Id<T> { | ||
29 | fn eq(&self, other: &Id<T>) -> bool { | ||
30 | self.idx == other.idx | ||
31 | } | ||
32 | } | ||
33 | |||
34 | impl<T> Eq for Id<T> {} | ||
35 | |||
36 | impl<T> Hash for Id<T> { | ||
37 | fn hash<H: Hasher>(&self, h: &mut H) { | ||
38 | self.idx.hash(h); | ||
39 | } | ||
40 | } | ||
41 | |||
42 | #[derive(Debug, PartialEq, Eq)] | ||
43 | pub(crate) struct ArenaBehavior<T> { | ||
44 | _ty: PhantomData<T>, | ||
45 | } | ||
46 | |||
47 | impl<T> id_arena::ArenaBehavior for ArenaBehavior<T> { | ||
48 | type Id = Id<T>; | ||
49 | fn new_arena_id() -> usize { | ||
50 | 0 | ||
51 | } | ||
52 | fn new_id(_arena_id: usize, index: usize) -> Id<T> { | ||
53 | Id { | ||
54 | idx: index as u32, | ||
55 | _ty: PhantomData, | ||
56 | } | ||
57 | } | ||
58 | fn index(id: Id<T>) -> usize { | ||
59 | id.idx as usize | ||
60 | } | ||
61 | fn arena_id(_id: Id<T>) -> usize { | ||
62 | 0 | ||
63 | } | ||
64 | } | ||
65 | |||
66 | pub(crate) type Arena<T> = id_arena::Arena<T, ArenaBehavior<T>>; | ||