1 // SPDX-License-Identifier: Apache-2.0 OR MIT 2 3 use proc_macro2::{Delimiter, TokenStream, TokenTree}; 4 use std::hash::{Hash, Hasher}; 5 6 pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree); 7 8 impl<'a> PartialEq for TokenTreeHelper<'a> { eq(&self, other: &Self) -> bool9 fn eq(&self, other: &Self) -> bool { 10 use proc_macro2::Spacing; 11 12 match (self.0, other.0) { 13 (TokenTree::Group(g1), TokenTree::Group(g2)) => { 14 match (g1.delimiter(), g2.delimiter()) { 15 (Delimiter::Parenthesis, Delimiter::Parenthesis) 16 | (Delimiter::Brace, Delimiter::Brace) 17 | (Delimiter::Bracket, Delimiter::Bracket) 18 | (Delimiter::None, Delimiter::None) => {} 19 _ => return false, 20 } 21 22 let s1 = g1.stream().into_iter(); 23 let mut s2 = g2.stream().into_iter(); 24 25 for item1 in s1 { 26 let item2 = match s2.next() { 27 Some(item) => item, 28 None => return false, 29 }; 30 if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) { 31 return false; 32 } 33 } 34 s2.next().is_none() 35 } 36 (TokenTree::Punct(o1), TokenTree::Punct(o2)) => { 37 o1.as_char() == o2.as_char() 38 && match (o1.spacing(), o2.spacing()) { 39 (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true, 40 _ => false, 41 } 42 } 43 (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(), 44 (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2, 45 _ => false, 46 } 47 } 48 } 49 50 impl<'a> Hash for TokenTreeHelper<'a> { hash<H: Hasher>(&self, h: &mut H)51 fn hash<H: Hasher>(&self, h: &mut H) { 52 use proc_macro2::Spacing; 53 54 match self.0 { 55 TokenTree::Group(g) => { 56 0u8.hash(h); 57 match g.delimiter() { 58 Delimiter::Parenthesis => 0u8.hash(h), 59 Delimiter::Brace => 1u8.hash(h), 60 Delimiter::Bracket => 2u8.hash(h), 61 Delimiter::None => 3u8.hash(h), 62 } 63 64 for item in g.stream() { 65 TokenTreeHelper(&item).hash(h); 66 } 67 0xFFu8.hash(h); // terminator w/ a variant we don't normally hash 68 } 69 TokenTree::Punct(op) => { 70 1u8.hash(h); 71 op.as_char().hash(h); 72 match op.spacing() { 73 Spacing::Alone => 0u8.hash(h), 74 Spacing::Joint => 1u8.hash(h), 75 } 76 } 77 TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h), 78 TokenTree::Ident(word) => (3u8, word).hash(h), 79 } 80 } 81 } 82 83 pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream); 84 85 impl<'a> PartialEq for TokenStreamHelper<'a> { eq(&self, other: &Self) -> bool86 fn eq(&self, other: &Self) -> bool { 87 let left = self.0.clone().into_iter().collect::<Vec<_>>(); 88 let right = other.0.clone().into_iter().collect::<Vec<_>>(); 89 if left.len() != right.len() { 90 return false; 91 } 92 for (a, b) in left.into_iter().zip(right) { 93 if TokenTreeHelper(&a) != TokenTreeHelper(&b) { 94 return false; 95 } 96 } 97 true 98 } 99 } 100 101 impl<'a> Hash for TokenStreamHelper<'a> { hash<H: Hasher>(&self, state: &mut H)102 fn hash<H: Hasher>(&self, state: &mut H) { 103 let tts = self.0.clone().into_iter().collect::<Vec<_>>(); 104 tts.len().hash(state); 105 for tt in tts { 106 TokenTreeHelper(&tt).hash(state); 107 } 108 } 109 } 110