syn/
tt.rs

1use alloc::string::ToString;
2use core::hash::{Hash, Hasher};
3use proc_macro2::{Delimiter, Spacing, TokenStream, TokenTree};
4
5pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree);
6
7impl<'a> PartialEq for TokenTreeHelper<'a> {
8    fn eq(&self, other: &Self) -> bool {
9        match (self.0, other.0) {
10            (TokenTree::Group(g1), TokenTree::Group(g2)) => {
11                match (g1.delimiter(), g2.delimiter()) {
12                    (Delimiter::Parenthesis, Delimiter::Parenthesis)
13                    | (Delimiter::Brace, Delimiter::Brace)
14                    | (Delimiter::Bracket, Delimiter::Bracket)
15                    | (Delimiter::None, Delimiter::None) => {}
16                    _ => return false,
17                }
18
19                TokenStreamHelper(&g1.stream()) == TokenStreamHelper(&g2.stream())
20            }
21            (TokenTree::Punct(o1), TokenTree::Punct(o2)) => {
22                o1.as_char() == o2.as_char()
23                    && match (o1.spacing(), o2.spacing()) {
24                        (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true,
25                        _ => false,
26                    }
27            }
28            (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(),
29            (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2,
30            _ => false,
31        }
32    }
33}
34
35impl<'a> Hash for TokenTreeHelper<'a> {
36    fn hash<H: Hasher>(&self, h: &mut H) {
37        match self.0 {
38            TokenTree::Group(g) => {
39                0u8.hash(h);
40                match g.delimiter() {
41                    Delimiter::Parenthesis => 0u8.hash(h),
42                    Delimiter::Brace => 1u8.hash(h),
43                    Delimiter::Bracket => 2u8.hash(h),
44                    Delimiter::None => 3u8.hash(h),
45                }
46
47                for item in g.stream() {
48                    TokenTreeHelper(&item).hash(h);
49                }
50                0xFFu8.hash(h); // terminator w/ a variant we don't normally hash
51            }
52            TokenTree::Punct(op) => {
53                1u8.hash(h);
54                op.as_char().hash(h);
55                match op.spacing() {
56                    Spacing::Alone => 0u8.hash(h),
57                    Spacing::Joint => 1u8.hash(h),
58                }
59            }
60            TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h),
61            TokenTree::Ident(word) => (3u8, word).hash(h),
62        }
63    }
64}
65
66pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream);
67
68impl<'a> PartialEq for TokenStreamHelper<'a> {
69    fn eq(&self, other: &Self) -> bool {
70        let left = self.0.clone().into_iter();
71        let mut right = other.0.clone().into_iter();
72
73        for item1 in left {
74            let item2 = match right.next() {
75                Some(item) => item,
76                None => return false,
77            };
78            if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) {
79                return false;
80            }
81        }
82
83        right.next().is_none()
84    }
85}
86
87impl<'a> Hash for TokenStreamHelper<'a> {
88    fn hash<H: Hasher>(&self, state: &mut H) {
89        let tokens = self.0.clone().into_iter();
90
91        tokens.clone().count().hash(state);
92
93        for tt in tokens {
94            TokenTreeHelper(&tt).hash(state);
95        }
96    }
97}
syn/tt.rs

syn/
tt.rs
