98 lines
3.2 KiB
Rust
98 lines
3.2 KiB
Rust
use alloc::string::ToString;
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use core::hash::{Hash, Hasher};
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use proc_macro2::{Delimiter, Spacing, TokenStream, TokenTree};
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pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree);
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impl<'a> PartialEq for TokenTreeHelper<'a> {
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fn eq(&self, other: &Self) -> bool {
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match (self.0, other.0) {
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(TokenTree::Group(g1), TokenTree::Group(g2)) => {
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match (g1.delimiter(), g2.delimiter()) {
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(Delimiter::Parenthesis, Delimiter::Parenthesis)
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| (Delimiter::Brace, Delimiter::Brace)
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| (Delimiter::Bracket, Delimiter::Bracket)
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| (Delimiter::None, Delimiter::None) => {}
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_ => return false,
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}
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TokenStreamHelper(&g1.stream()) == TokenStreamHelper(&g2.stream())
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}
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(TokenTree::Punct(o1), TokenTree::Punct(o2)) => {
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o1.as_char() == o2.as_char()
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&& match (o1.spacing(), o2.spacing()) {
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(Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true,
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_ => false,
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}
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}
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(TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(),
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(TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2,
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_ => false,
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}
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}
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}
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impl<'a> Hash for TokenTreeHelper<'a> {
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fn hash<H: Hasher>(&self, h: &mut H) {
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match self.0 {
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TokenTree::Group(g) => {
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0u8.hash(h);
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match g.delimiter() {
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Delimiter::Parenthesis => 0u8.hash(h),
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Delimiter::Brace => 1u8.hash(h),
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Delimiter::Bracket => 2u8.hash(h),
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Delimiter::None => 3u8.hash(h),
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}
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for item in g.stream() {
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TokenTreeHelper(&item).hash(h);
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}
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0xFFu8.hash(h); // terminator w/ a variant we don't normally hash
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}
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TokenTree::Punct(op) => {
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1u8.hash(h);
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op.as_char().hash(h);
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match op.spacing() {
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Spacing::Alone => 0u8.hash(h),
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Spacing::Joint => 1u8.hash(h),
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}
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}
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TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h),
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TokenTree::Ident(word) => (3u8, word).hash(h),
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}
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}
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}
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pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream);
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impl<'a> PartialEq for TokenStreamHelper<'a> {
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fn eq(&self, other: &Self) -> bool {
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let left = self.0.clone().into_iter();
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let mut right = other.0.clone().into_iter();
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for item1 in left {
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let item2 = match right.next() {
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Some(item) => item,
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None => return false,
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};
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if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) {
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return false;
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}
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}
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right.next().is_none()
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}
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}
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impl<'a> Hash for TokenStreamHelper<'a> {
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fn hash<H: Hasher>(&self, state: &mut H) {
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let tokens = self.0.clone().into_iter();
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tokens.clone().count().hash(state);
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for tt in tokens {
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TokenTreeHelper(&tt).hash(state);
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}
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}
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}
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