1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
use rustc_hash::FxHashSet;
use ra_syntax::{
ast,
AstNode,
File, TextRange, SyntaxNodeRef,
SyntaxKind::{self, *},
Direction,
};
#[derive(Debug, PartialEq, Eq)]
pub enum FoldKind {
Comment,
Imports,
}
#[derive(Debug)]
pub struct Fold {
pub range: TextRange,
pub kind: FoldKind,
}
pub fn folding_ranges(file: &File) -> Vec<Fold> {
let mut res = vec![];
let mut visited_comments = FxHashSet::default();
for node in file.syntax().descendants() {
// Fold items that span multiple lines
if let Some(kind) = fold_kind(node.kind()) {
if has_newline(node) {
res.push(Fold { range: node.range(), kind });
}
}
// Also fold groups of comments
if visited_comments.contains(&node) {
continue;
}
if node.kind() == COMMENT {
contiguous_range_for_comment(node, &mut visited_comments)
.map(|range| res.push(Fold { range, kind: FoldKind::Comment }));
}
}
res
}
fn fold_kind(kind: SyntaxKind) -> Option<FoldKind> {
match kind {
COMMENT => Some(FoldKind::Comment),
USE_ITEM => Some(FoldKind::Imports),
_ => None
}
}
fn has_newline(
node: SyntaxNodeRef,
) -> bool {
for descendant in node.descendants() {
if let Some(ws) = ast::Whitespace::cast(descendant) {
if ws.has_newlines() {
return true;
}
} else if let Some(comment) = ast::Comment::cast(descendant) {
if comment.has_newlines() {
return true;
}
}
}
false
}
fn contiguous_range_for_comment<'a>(
first: SyntaxNodeRef<'a>,
visited: &mut FxHashSet<SyntaxNodeRef<'a>>,
) -> Option<TextRange> {
visited.insert(first);
// Only fold comments of the same flavor
let group_flavor = ast::Comment::cast(first)?.flavor();
let mut last = first;
for node in first.siblings(Direction::Next) {
if let Some(ws) = ast::Whitespace::cast(node) {
// There is a blank line, which means the group ends here
if ws.count_newlines_lazy().take(2).count() == 2 {
break;
}
// Ignore whitespace without blank lines
continue;
}
match ast::Comment::cast(node) {
Some(next_comment) if next_comment.flavor() == group_flavor => {
visited.insert(node);
last = node;
}
// The comment group ends because either:
// * An element of a different kind was reached
// * A comment of a different flavor was reached
_ => {
break
}
}
}
if first != last {
Some(TextRange::from_to(
first.range().start(),
last.range().end(),
))
} else {
// The group consists of only one element, therefore it cannot be folded
None
}
}
#[cfg(test)]
mod tests {
use super::*;
use test_utils::extract_ranges;
fn do_check(text: &str, fold_kinds: &[FoldKind]) {
let (ranges, text) = extract_ranges(text);
let file = File::parse(&text);
let folds = folding_ranges(&file);
assert_eq!(folds.len(), ranges.len());
for ((fold, range), fold_kind) in folds.into_iter().zip(ranges.into_iter()).zip(fold_kinds.into_iter()) {
assert_eq!(fold.range.start(), range.start());
assert_eq!(fold.range.end(), range.end());
assert_eq!(&fold.kind, fold_kind);
}
}
#[test]
fn test_fold_comments() {
let text = r#"
<|>// Hello
// this is a multiline
// comment
//<|>
// But this is not
fn main() {
<|>// We should
// also
// fold
// this one.<|>
<|>//! But this one is different
//! because it has another flavor<|>
<|>/* As does this
multiline comment */<|>
}"#;
let fold_kinds = &[
FoldKind::Comment,
FoldKind::Comment,
FoldKind::Comment,
FoldKind::Comment,
];
do_check(text, fold_kinds);
}
#[test]
fn test_fold_imports() {
let text = r#"
<|>use std::{
str,
vec,
io as iop
};<|>
fn main() {
}"#;
let folds = &[FoldKind::Imports];
do_check(text, folds);
}
}
|
