syn/
tt.rs

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1use proc_macro2::{Delimiter, TokenStream, TokenTree};
2use std::hash::{Hash, Hasher};
3
4pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree);
5
6impl<'a> PartialEq for TokenTreeHelper<'a> {
7    fn eq(&self, other: &Self) -> bool {
8        use proc_macro2::Spacing;
9
10        match (self.0, other.0) {
11            (TokenTree::Group(g1), TokenTree::Group(g2)) => {
12                match (g1.delimiter(), g2.delimiter()) {
13                    (Delimiter::Parenthesis, Delimiter::Parenthesis)
14                    | (Delimiter::Brace, Delimiter::Brace)
15                    | (Delimiter::Bracket, Delimiter::Bracket)
16                    | (Delimiter::None, Delimiter::None) => {}
17                    _ => return false,
18                }
19
20                let s1 = g1.stream().into_iter();
21                let mut s2 = g2.stream().into_iter();
22
23                for item1 in s1 {
24                    let item2 = match s2.next() {
25                        Some(item) => item,
26                        None => return false,
27                    };
28                    if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) {
29                        return false;
30                    }
31                }
32                s2.next().is_none()
33            }
34            (TokenTree::Punct(o1), TokenTree::Punct(o2)) => {
35                o1.as_char() == o2.as_char()
36                    && match (o1.spacing(), o2.spacing()) {
37                        (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true,
38                        _ => false,
39                    }
40            }
41            (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(),
42            (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2,
43            _ => false,
44        }
45    }
46}
47
48impl<'a> Hash for TokenTreeHelper<'a> {
49    fn hash<H: Hasher>(&self, h: &mut H) {
50        use proc_macro2::Spacing;
51
52        match self.0 {
53            TokenTree::Group(g) => {
54                0u8.hash(h);
55                match g.delimiter() {
56                    Delimiter::Parenthesis => 0u8.hash(h),
57                    Delimiter::Brace => 1u8.hash(h),
58                    Delimiter::Bracket => 2u8.hash(h),
59                    Delimiter::None => 3u8.hash(h),
60                }
61
62                for item in g.stream() {
63                    TokenTreeHelper(&item).hash(h);
64                }
65                0xFFu8.hash(h); // terminator w/ a variant we don't normally hash
66            }
67            TokenTree::Punct(op) => {
68                1u8.hash(h);
69                op.as_char().hash(h);
70                match op.spacing() {
71                    Spacing::Alone => 0u8.hash(h),
72                    Spacing::Joint => 1u8.hash(h),
73                }
74            }
75            TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h),
76            TokenTree::Ident(word) => (3u8, word).hash(h),
77        }
78    }
79}
80
81pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream);
82
83impl<'a> PartialEq for TokenStreamHelper<'a> {
84    fn eq(&self, other: &Self) -> bool {
85        let left = self.0.clone().into_iter().collect::<Vec<_>>();
86        let right = other.0.clone().into_iter().collect::<Vec<_>>();
87        if left.len() != right.len() {
88            return false;
89        }
90        for (a, b) in left.into_iter().zip(right) {
91            if TokenTreeHelper(&a) != TokenTreeHelper(&b) {
92                return false;
93            }
94        }
95        true
96    }
97}
98
99impl<'a> Hash for TokenStreamHelper<'a> {
100    fn hash<H: Hasher>(&self, state: &mut H) {
101        let tts = self.0.clone().into_iter().collect::<Vec<_>>();
102        tts.len().hash(state);
103        for tt in tts {
104            TokenTreeHelper(&tt).hash(state);
105        }
106    }
107}
syn/tt.rs

syn/
tt.rs
