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// Copyright 2018 Syn Developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::hash::{Hash, Hasher};
use proc_macro2::{Delimiter, TokenStream, TokenTree};
pub struct TokenTreeHelper<'a>(pub &'a TokenTree);
impl<'a> PartialEq for TokenTreeHelper<'a> {
fn eq(&self, other: &Self) -> bool {
use proc_macro2::Spacing;
match (self.0, other.0) {
(&TokenTree::Group(ref g1), &TokenTree::Group(ref g2)) => {
match (g1.delimiter(), g2.delimiter()) {
(Delimiter::Parenthesis, Delimiter::Parenthesis)
| (Delimiter::Brace, Delimiter::Brace)
| (Delimiter::Bracket, Delimiter::Bracket)
| (Delimiter::None, Delimiter::None) => {}
_ => return false,
}
let s1 = g1.stream().clone().into_iter();
let mut s2 = g2.stream().clone().into_iter();
for item1 in s1 {
let item2 = match s2.next() {
Some(item) => item,
None => return false,
};
if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) {
return false;
}
}
s2.next().is_none()
}
(&TokenTree::Punct(ref o1), &TokenTree::Punct(ref o2)) => {
o1.as_char() == o2.as_char()
&& match (o1.spacing(), o2.spacing()) {
(Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true,
_ => false,
}
}
(&TokenTree::Literal(ref l1), &TokenTree::Literal(ref l2)) => {
l1.to_string() == l2.to_string()
}
(&TokenTree::Ident(ref s1), &TokenTree::Ident(ref s2)) => s1 == s2,
_ => false,
}
}
}
impl<'a> Hash for TokenTreeHelper<'a> {
fn hash<H: Hasher>(&self, h: &mut H) {
use proc_macro2::Spacing;
match *self.0 {
TokenTree::Group(ref g) => {
0u8.hash(h);
match g.delimiter() {
Delimiter::Parenthesis => 0u8.hash(h),
Delimiter::Brace => 1u8.hash(h),
Delimiter::Bracket => 2u8.hash(h),
Delimiter::None => 3u8.hash(h),
}
for item in g.stream().clone() {
TokenTreeHelper(&item).hash(h);
}
0xffu8.hash(h); // terminator w/ a variant we don't normally hash
}
TokenTree::Punct(ref op) => {
1u8.hash(h);
op.as_char().hash(h);
match op.spacing() {
Spacing::Alone => 0u8.hash(h),
Spacing::Joint => 1u8.hash(h),
}
}
TokenTree::Literal(ref lit) => (2u8, lit.to_string()).hash(h),
TokenTree::Ident(ref word) => (3u8, word).hash(h),
}
}
}
pub struct TokenStreamHelper<'a>(pub &'a TokenStream);
impl<'a> PartialEq for TokenStreamHelper<'a> {
fn eq(&self, other: &Self) -> bool {
let left = self.0.clone().into_iter().collect::<Vec<_>>();
let right = other.0.clone().into_iter().collect::<Vec<_>>();
if left.len() != right.len() {
return false;
}
for (a, b) in left.into_iter().zip(right) {
if TokenTreeHelper(&a) != TokenTreeHelper(&b) {
return false;
}
}
true
}
}
impl<'a> Hash for TokenStreamHelper<'a> {
fn hash<H: Hasher>(&self, state: &mut H) {
let tts = self.0.clone().into_iter().collect::<Vec<_>>();
tts.len().hash(state);
for tt in tts {
TokenTreeHelper(&tt).hash(state);
}
}
}