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-rw-r--r--crates/text_edit/src/lib.rs186
1 files changed, 186 insertions, 0 deletions
diff --git a/crates/text_edit/src/lib.rs b/crates/text_edit/src/lib.rs
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1//! Representation of a `TextEdit`.
2//!
3//! `rust-analyzer` never mutates text itself and only sends diffs to clients,
4//! so `TextEdit` is the ultimate representation of the work done by
5//! rust-analyzer.
6pub use text_size::{TextRange, TextSize};
7
8/// `InsertDelete` -- a single "atomic" change to text
9///
10/// Must not overlap with other `InDel`s
11#[derive(Debug, Clone)]
12pub struct Indel {
13 pub insert: String,
14 /// Refers to offsets in the original text
15 pub delete: TextRange,
16}
17
18#[derive(Default, Debug, Clone)]
19pub struct TextEdit {
20 indels: Vec<Indel>,
21}
22
23#[derive(Debug, Default, Clone)]
24pub struct TextEditBuilder {
25 indels: Vec<Indel>,
26}
27
28impl Indel {
29 pub fn insert(offset: TextSize, text: String) -> Indel {
30 Indel::replace(TextRange::empty(offset), text)
31 }
32 pub fn delete(range: TextRange) -> Indel {
33 Indel::replace(range, String::new())
34 }
35 pub fn replace(range: TextRange, replace_with: String) -> Indel {
36 Indel { delete: range, insert: replace_with }
37 }
38
39 pub fn apply(&self, text: &mut String) {
40 let start: usize = self.delete.start().into();
41 let end: usize = self.delete.end().into();
42 text.replace_range(start..end, &self.insert);
43 }
44}
45
46impl TextEdit {
47 pub fn builder() -> TextEditBuilder {
48 TextEditBuilder::default()
49 }
50
51 pub fn insert(offset: TextSize, text: String) -> TextEdit {
52 let mut builder = TextEdit::builder();
53 builder.insert(offset, text);
54 builder.finish()
55 }
56
57 pub fn delete(range: TextRange) -> TextEdit {
58 let mut builder = TextEdit::builder();
59 builder.delete(range);
60 builder.finish()
61 }
62
63 pub fn replace(range: TextRange, replace_with: String) -> TextEdit {
64 let mut builder = TextEdit::builder();
65 builder.replace(range, replace_with);
66 builder.finish()
67 }
68
69 pub fn len(&self) -> usize {
70 self.indels.len()
71 }
72
73 pub fn is_empty(&self) -> bool {
74 self.indels.is_empty()
75 }
76
77 pub fn iter(&self) -> std::slice::Iter<'_, Indel> {
78 self.into_iter()
79 }
80
81 pub fn apply(&self, text: &mut String) {
82 match self.len() {
83 0 => return,
84 1 => {
85 self.indels[0].apply(text);
86 return;
87 }
88 _ => (),
89 }
90
91 let mut total_len = TextSize::of(&*text);
92 for indel in self.indels.iter() {
93 total_len += TextSize::of(&indel.insert);
94 total_len -= indel.delete.end() - indel.delete.start();
95 }
96 let mut buf = String::with_capacity(total_len.into());
97 let mut prev = 0;
98 for indel in self.indels.iter() {
99 let start: usize = indel.delete.start().into();
100 let end: usize = indel.delete.end().into();
101 if start > prev {
102 buf.push_str(&text[prev..start]);
103 }
104 buf.push_str(&indel.insert);
105 prev = end;
106 }
107 buf.push_str(&text[prev..text.len()]);
108 assert_eq!(TextSize::of(&buf), total_len);
109
110 // FIXME: figure out a way to mutate the text in-place or reuse the
111 // memory in some other way
112 *text = buf
113 }
114
115 pub fn union(&mut self, other: TextEdit) -> Result<(), TextEdit> {
116 // FIXME: can be done without allocating intermediate vector
117 let mut all = self.iter().chain(other.iter()).collect::<Vec<_>>();
118 if !check_disjoint(&mut all) {
119 return Err(other);
120 }
121 self.indels.extend(other.indels);
122 assert!(check_disjoint(&mut self.indels));
123 Ok(())
124 }
125
126 pub fn apply_to_offset(&self, offset: TextSize) -> Option<TextSize> {
127 let mut res = offset;
128 for indel in self.indels.iter() {
129 if indel.delete.start() >= offset {
130 break;
131 }
132 if offset < indel.delete.end() {
133 return None;
134 }
135 res += TextSize::of(&indel.insert);
136 res -= indel.delete.len();
137 }
138 Some(res)
139 }
140}
141
142impl IntoIterator for TextEdit {
143 type Item = Indel;
144 type IntoIter = std::vec::IntoIter<Indel>;
145
146 fn into_iter(self) -> Self::IntoIter {
147 self.indels.into_iter()
148 }
149}
150
151impl<'a> IntoIterator for &'a TextEdit {
152 type Item = &'a Indel;
153 type IntoIter = std::slice::Iter<'a, Indel>;
154
155 fn into_iter(self) -> Self::IntoIter {
156 self.indels.iter()
157 }
158}
159
160impl TextEditBuilder {
161 pub fn replace(&mut self, range: TextRange, replace_with: String) {
162 self.indels.push(Indel::replace(range, replace_with))
163 }
164 pub fn delete(&mut self, range: TextRange) {
165 self.indels.push(Indel::delete(range))
166 }
167 pub fn insert(&mut self, offset: TextSize, text: String) {
168 self.indels.push(Indel::insert(offset, text))
169 }
170 pub fn finish(self) -> TextEdit {
171 let mut indels = self.indels;
172 assert!(check_disjoint(&mut indels));
173 TextEdit { indels }
174 }
175 pub fn invalidates_offset(&self, offset: TextSize) -> bool {
176 self.indels.iter().any(|indel| indel.delete.contains_inclusive(offset))
177 }
178}
179
180fn check_disjoint(indels: &mut [impl std::borrow::Borrow<Indel>]) -> bool {
181 indels.sort_by_key(|indel| (indel.borrow().delete.start(), indel.borrow().delete.end()));
182 indels
183 .iter()
184 .zip(indels.iter().skip(1))
185 .all(|(l, r)| l.borrow().delete.end() <= r.borrow().delete.start())
186}