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edwin0chengedwin0cheng
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Simplify SubtreeTokenSource
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+60
-88
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+60
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‎crates/mbe/src/subtree_source.rs

Lines changed: 60 additions & 88 deletions
Original file line numberDiff line numberDiff line change
@@ -1,145 +1,117 @@
11
//! FIXME: write short doc here
22
33
use parser::{Token, TokenSource};
4-
use std::cell::{Cell, Ref, RefCell};
54
use syntax::{lex_single_syntax_kind, SmolStr, SyntaxKind, SyntaxKind::*, T};
6-
use tt::buffer::{Cursor, TokenBuffer};
5+
use tt::buffer::TokenBuffer;
76

87
#[derive(Debug, Clone, Eq, PartialEq)]
98
struct TtToken {
10-
kind: SyntaxKind,
11-
is_joint_to_next: bool,
9+
tt: Token,
1210
text: SmolStr,
1311
}
1412

15-
pub(crate) struct SubtreeTokenSource<'a> {
16-
cached_cursor: Cell<Cursor<'a>>,
17-
cached: RefCell<Vec<Option<TtToken>>>,
13+
pub(crate) struct SubtreeTokenSource {
14+
cached: Vec<TtToken>,
1815
curr: (Token, usize),
1916
}
2017

21-
impl<'a> SubtreeTokenSource<'a> {
18+
impl<'a> SubtreeTokenSource {
2219
// Helper function used in test
2320
#[cfg(test)]
2421
pub(crate) fn text(&self) -> SmolStr {
25-
match *self.get(self.curr.1) {
22+
match self.cached.get(self.curr.1) {
2623
Some(ref tt) => tt.text.clone(),
2724
_ => SmolStr::new(""),
2825
}
2926
}
3027
}
3128

32-
impl<'a> SubtreeTokenSource<'a> {
33-
pub(crate) fn new(buffer: &'a TokenBuffer) -> SubtreeTokenSource<'a> {
34-
let cursor = buffer.begin();
29+
impl<'a> SubtreeTokenSource {
30+
pub(crate) fn new(buffer: &TokenBuffer) -> SubtreeTokenSource {
31+
let mut current = buffer.begin();
32+
let mut cached = Vec::with_capacity(100);
3533

36-
let mut res = SubtreeTokenSource {
37-
curr: (Token { kind: EOF, is_jointed_to_next: false }, 0),
38-
cached_cursor: Cell::new(cursor),
39-
cached: RefCell::new(Vec::with_capacity(10)),
40-
};
41-
res.curr = (res.mk_token(0), 0);
42-
res
43-
}
34+
while !current.eof() {
35+
let cursor = current;
36+
let tt = cursor.token_tree();
4437

45-
fn mk_token(&self, pos: usize) -> Token {
46-
match *self.get(pos) {
47-
Some(ref tt) => Token { kind: tt.kind, is_jointed_to_next: tt.is_joint_to_next },
48-
None => Token { kind: EOF, is_jointed_to_next: false },
49-
}
50-
}
51-
52-
fn get(&self, pos: usize) -> Ref<Option<TtToken>> {
53-
fn is_lifetime(c: Cursor) -> Option<(Cursor, SmolStr)> {
54-
let tkn = c.token_tree();
55-
56-
if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(punct), _)) = tkn {
38+
// Check if it is lifetime
39+
if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(punct), _)) = tt {
5740
if punct.char == '\'' {
58-
let next = c.bump();
41+
let next = cursor.bump();
5942
if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Ident(ident), _)) =
6043
next.token_tree()
6144
{
62-
let res_cursor = next.bump();
63-
let text = SmolStr::new("'".to_string() + &ident.to_string());
64-
65-
return Some((res_cursor, text));
45+
let text = SmolStr::new("'".to_string() + &ident.text);
46+
cached.push(TtToken {
47+
tt: Token { kind: LIFETIME_IDENT, is_jointed_to_next: false },
48+
text,
49+
});
50+
current = next.bump();
51+
continue;
6652
} else {
6753
panic!("Next token must be ident : {:#?}", next.token_tree());
6854
}
6955
}
7056
}
7157

72-
None
73-
}
74-
75-
if pos < self.cached.borrow().len() {
76-
return Ref::map(self.cached.borrow(), |c| &c[pos]);
77-
}
78-
79-
{
80-
let mut cached = self.cached.borrow_mut();
81-
while pos >= cached.len() {
82-
let cursor = self.cached_cursor.get();
83-
if cursor.eof() {
84-
cached.push(None);
85-
continue;
58+
current = match tt {
59+
Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
60+
cached.push(convert_leaf(&leaf));
61+
cursor.bump()
8662
}
87-
88-
if let Some((curr, text)) = is_lifetime(cursor) {
89-
cached.push(Some(TtToken {
90-
kind: LIFETIME_IDENT,
91-
is_joint_to_next: false,
92-
text,
93-
}));
94-
self.cached_cursor.set(curr);
95-
continue;
63+
Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
64+
cached.push(convert_delim(subtree.delimiter_kind(), false));
65+
cursor.subtree().unwrap()
9666
}
97-
98-
match cursor.token_tree() {
99-
Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
100-
cached.push(Some(convert_leaf(&leaf)));
101-
self.cached_cursor.set(cursor.bump());
102-
}
103-
Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
104-
self.cached_cursor.set(cursor.subtree().unwrap());
105-
cached.push(Some(convert_delim(subtree.delimiter_kind(), false)));
106-
}
107-
None => {
108-
if let Some(subtree) = cursor.end() {
109-
cached.push(Some(convert_delim(subtree.delimiter_kind(), true)));
110-
self.cached_cursor.set(cursor.bump());
111-
}
67+
None => {
68+
if let Some(subtree) = cursor.end() {
69+
cached.push(convert_delim(subtree.delimiter_kind(), true));
70+
cursor.bump()
71+
} else {
72+
continue;
11273
}
11374
}
114-
}
75+
};
11576
}
11677

117-
Ref::map(self.cached.borrow(), |c| &c[pos])
78+
let mut res = SubtreeTokenSource {
79+
curr: (Token { kind: EOF, is_jointed_to_next: false }, 0),
80+
cached,
81+
};
82+
res.curr = (res.token(0), 0);
83+
res
84+
}
85+
86+
fn token(&self, pos: usize) -> Token {
87+
match self.cached.get(pos) {
88+
Some(it) => it.tt,
89+
None => Token { kind: EOF, is_jointed_to_next: false },
90+
}
11891
}
11992
}
12093

121-
impl<'a> TokenSource for SubtreeTokenSource<'a> {
94+
impl<'a> TokenSource for SubtreeTokenSource {
12295
fn current(&self) -> Token {
12396
self.curr.0
12497
}
12598

12699
/// Lookahead n token
127100
fn lookahead_nth(&self, n: usize) -> Token {
128-
self.mk_token(self.curr.1 + n)
101+
self.token(self.curr.1 + n)
129102
}
130103

131104
/// bump cursor to next token
132105
fn bump(&mut self) {
133106
if self.current().kind == EOF {
134107
return;
135108
}
136-
137-
self.curr = (self.mk_token(self.curr.1 + 1), self.curr.1 + 1);
109+
self.curr = (self.token(self.curr.1 + 1), self.curr.1 + 1);
138110
}
139111

140112
/// Is the current token a specified keyword?
141113
fn is_keyword(&self, kw: &str) -> bool {
142-
match *self.get(self.curr.1) {
114+
match self.cached.get(self.curr.1) {
143115
Some(ref t) => t.text == *kw,
144116
_ => false,
145117
}
@@ -157,7 +129,7 @@ fn convert_delim(d: Option<tt::DelimiterKind>, closing: bool) -> TtToken {
157129
let idx = closing as usize;
158130
let kind = kinds[idx];
159131
let text = if !texts.is_empty() { &texts[idx..texts.len() - (1 - idx)] } else { "" };
160-
TtToken { kind, is_joint_to_next: false, text: SmolStr::new(text) }
132+
TtToken { tt: Token { kind, is_jointed_to_next: false }, text: SmolStr::new(text) }
161133
}
162134

163135
fn convert_literal(l: &tt::Literal) -> TtToken {
@@ -171,7 +143,7 @@ fn convert_literal(l: &tt::Literal) -> TtToken {
171143
})
172144
.unwrap_or_else(|| panic!("Fail to convert given literal {:#?}", &l));
173145

174-
TtToken { kind, is_joint_to_next: false, text: l.text.clone() }
146+
TtToken { tt: Token { kind, is_jointed_to_next: false }, text: l.text.clone() }
175147
}
176148

177149
fn convert_ident(ident: &tt::Ident) -> TtToken {
@@ -182,7 +154,7 @@ fn convert_ident(ident: &tt::Ident) -> TtToken {
182154
_ => SyntaxKind::from_keyword(ident.text.as_str()).unwrap_or(IDENT),
183155
};
184156

185-
TtToken { kind, is_joint_to_next: false, text: ident.text.clone() }
157+
TtToken { tt: Token { kind, is_jointed_to_next: false }, text: ident.text.clone() }
186158
}
187159

188160
fn convert_punct(p: tt::Punct) -> TtToken {
@@ -196,7 +168,7 @@ fn convert_punct(p: tt::Punct) -> TtToken {
196168
let s: &str = p.char.encode_utf8(&mut buf);
197169
SmolStr::new(s)
198170
};
199-
TtToken { kind, is_joint_to_next: p.spacing == tt::Spacing::Joint, text }
171+
TtToken { tt: Token { kind, is_jointed_to_next: p.spacing == tt::Spacing::Joint }, text }
200172
}
201173

202174
fn convert_leaf(leaf: &tt::Leaf) -> TtToken {
@@ -210,6 +182,7 @@ fn convert_leaf(leaf: &tt::Leaf) -> TtToken {
210182
#[cfg(test)]
211183
mod tests {
212184
use super::{convert_literal, TtToken};
185+
use parser::Token;
213186
use syntax::{SmolStr, SyntaxKind};
214187

215188
#[test]
@@ -220,8 +193,7 @@ mod tests {
220193
text: SmolStr::new("-42.0")
221194
}),
222195
TtToken {
223-
kind: SyntaxKind::FLOAT_NUMBER,
224-
is_joint_to_next: false,
196+
tt: Token { kind: SyntaxKind::FLOAT_NUMBER, is_jointed_to_next: false },
225197
text: SmolStr::new("-42.0")
226198
}
227199
);

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