1use std::ops::Range;
2use sum_tree::SumTree;
3use text::{Anchor, BufferSnapshot, OffsetRangeExt, Point};
4
5pub use git2 as libgit;
6use libgit::{DiffLineType as GitDiffLineType, DiffOptions as GitOptions, Patch as GitPatch};
7
8#[derive(Debug, Clone, Copy, PartialEq, Eq)]
9pub enum DiffHunkStatus {
10 Added,
11 Modified,
12 Removed,
13}
14
15#[derive(Debug, Clone, PartialEq, Eq)]
16pub struct DiffHunk<T> {
17 pub buffer_range: Range<T>,
18 pub diff_base_byte_range: Range<usize>,
19}
20
21impl DiffHunk<u32> {
22 pub fn status(&self) -> DiffHunkStatus {
23 if self.diff_base_byte_range.is_empty() {
24 DiffHunkStatus::Added
25 } else if self.buffer_range.is_empty() {
26 DiffHunkStatus::Removed
27 } else {
28 DiffHunkStatus::Modified
29 }
30 }
31}
32
33impl sum_tree::Item for DiffHunk<Anchor> {
34 type Summary = DiffHunkSummary;
35
36 fn summary(&self) -> Self::Summary {
37 DiffHunkSummary {
38 buffer_range: self.buffer_range.clone(),
39 }
40 }
41}
42
43#[derive(Debug, Default, Clone)]
44pub struct DiffHunkSummary {
45 buffer_range: Range<Anchor>,
46}
47
48impl sum_tree::Summary for DiffHunkSummary {
49 type Context = text::BufferSnapshot;
50
51 fn add_summary(&mut self, other: &Self, buffer: &Self::Context) {
52 self.buffer_range.start = self
53 .buffer_range
54 .start
55 .min(&other.buffer_range.start, buffer);
56 self.buffer_range.end = self.buffer_range.end.max(&other.buffer_range.end, buffer);
57 }
58}
59
60#[derive(Clone)]
61pub struct BufferDiff {
62 last_buffer_version: Option<clock::Global>,
63 tree: SumTree<DiffHunk<Anchor>>,
64}
65
66impl BufferDiff {
67 pub fn new() -> BufferDiff {
68 BufferDiff {
69 last_buffer_version: None,
70 tree: SumTree::new(),
71 }
72 }
73
74 pub fn hunks_in_range<'a>(
75 &'a self,
76 range: Range<Anchor>,
77 buffer: &'a BufferSnapshot,
78 reversed: bool,
79 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
80 // let start = buffer.anchor_before(Point::new(query_row_range.start, 0));
81 // let end = buffer.anchor_after(Point::new(query_row_range.end, 0));
82
83 let mut cursor = self.tree.filter::<_, DiffHunkSummary>(move |summary| {
84 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
85 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
86 !before_start && !after_end
87 });
88
89 std::iter::from_fn(move || {
90 if reversed {
91 cursor.prev(buffer);
92 } else {
93 cursor.next(buffer);
94 }
95
96 let hunk = cursor.item()?;
97
98 let range = hunk.buffer_range.to_point(buffer);
99 let end_row = if range.end.column > 0 {
100 range.end.row + 1
101 } else {
102 range.end.row
103 };
104
105 Some(DiffHunk {
106 buffer_range: range.start.row..end_row,
107 diff_base_byte_range: hunk.diff_base_byte_range.clone(),
108 })
109 })
110 }
111
112 pub fn clear(&mut self, buffer: &text::BufferSnapshot) {
113 self.last_buffer_version = Some(buffer.version().clone());
114 self.tree = SumTree::new();
115 }
116
117 pub fn needs_update(&self, buffer: &text::BufferSnapshot) -> bool {
118 match &self.last_buffer_version {
119 Some(last) => buffer.version().changed_since(last),
120 None => true,
121 }
122 }
123
124 pub async fn update(&mut self, diff_base: &str, buffer: &text::BufferSnapshot) {
125 let mut tree = SumTree::new();
126
127 let buffer_text = buffer.as_rope().to_string();
128 let patch = Self::diff(&diff_base, &buffer_text);
129
130 if let Some(patch) = patch {
131 let mut divergence = 0;
132 for hunk_index in 0..patch.num_hunks() {
133 let hunk = Self::process_patch_hunk(&patch, hunk_index, buffer, &mut divergence);
134 tree.push(hunk, buffer);
135 }
136 }
137
138 self.tree = tree;
139 self.last_buffer_version = Some(buffer.version().clone());
140 }
141
142 #[cfg(test)]
143 fn hunks<'a>(&'a self, text: &'a BufferSnapshot) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
144 self.hunks_in_range(0..u32::MAX, text, false)
145 }
146
147 fn diff<'a>(head: &'a str, current: &'a str) -> Option<GitPatch<'a>> {
148 let mut options = GitOptions::default();
149 options.context_lines(0);
150
151 let patch = GitPatch::from_buffers(
152 head.as_bytes(),
153 None,
154 current.as_bytes(),
155 None,
156 Some(&mut options),
157 );
158
159 match patch {
160 Ok(patch) => Some(patch),
161
162 Err(err) => {
163 log::error!("`GitPatch::from_buffers` failed: {}", err);
164 None
165 }
166 }
167 }
168
169 fn process_patch_hunk<'a>(
170 patch: &GitPatch<'a>,
171 hunk_index: usize,
172 buffer: &text::BufferSnapshot,
173 buffer_row_divergence: &mut i64,
174 ) -> DiffHunk<Anchor> {
175 let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
176 assert!(line_item_count > 0);
177
178 let mut first_deletion_buffer_row: Option<u32> = None;
179 let mut buffer_row_range: Option<Range<u32>> = None;
180 let mut diff_base_byte_range: Option<Range<usize>> = None;
181
182 for line_index in 0..line_item_count {
183 let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
184 let kind = line.origin_value();
185 let content_offset = line.content_offset() as isize;
186 let content_len = line.content().len() as isize;
187
188 if kind == GitDiffLineType::Addition {
189 *buffer_row_divergence += 1;
190 let row = line.new_lineno().unwrap().saturating_sub(1);
191
192 match &mut buffer_row_range {
193 Some(buffer_row_range) => buffer_row_range.end = row + 1,
194 None => buffer_row_range = Some(row..row + 1),
195 }
196 }
197
198 if kind == GitDiffLineType::Deletion {
199 let end = content_offset + content_len;
200
201 match &mut diff_base_byte_range {
202 Some(head_byte_range) => head_byte_range.end = end as usize,
203 None => diff_base_byte_range = Some(content_offset as usize..end as usize),
204 }
205
206 if first_deletion_buffer_row.is_none() {
207 let old_row = line.old_lineno().unwrap().saturating_sub(1);
208 let row = old_row as i64 + *buffer_row_divergence;
209 first_deletion_buffer_row = Some(row as u32);
210 }
211
212 *buffer_row_divergence -= 1;
213 }
214 }
215
216 //unwrap_or deletion without addition
217 let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
218 //we cannot have an addition-less hunk without deletion(s) or else there would be no hunk
219 let row = first_deletion_buffer_row.unwrap();
220 row..row
221 });
222
223 //unwrap_or addition without deletion
224 let diff_base_byte_range = diff_base_byte_range.unwrap_or(0..0);
225
226 let start = Point::new(buffer_row_range.start, 0);
227 let end = Point::new(buffer_row_range.end, 0);
228 let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
229 DiffHunk {
230 buffer_range,
231 diff_base_byte_range,
232 }
233 }
234}
235
236/// Range (crossing new lines), old, new
237#[cfg(any(test, feature = "test-support"))]
238#[track_caller]
239pub fn assert_hunks<Iter>(
240 diff_hunks: Iter,
241 buffer: &BufferSnapshot,
242 diff_base: &str,
243 expected_hunks: &[(Range<u32>, &str, &str)],
244) where
245 Iter: Iterator<Item = DiffHunk<u32>>,
246{
247 let actual_hunks = diff_hunks
248 .map(|hunk| {
249 (
250 hunk.buffer_range.clone(),
251 &diff_base[hunk.diff_base_byte_range],
252 buffer
253 .text_for_range(
254 Point::new(hunk.buffer_range.start, 0)
255 ..Point::new(hunk.buffer_range.end, 0),
256 )
257 .collect::<String>(),
258 )
259 })
260 .collect::<Vec<_>>();
261
262 let expected_hunks: Vec<_> = expected_hunks
263 .iter()
264 .map(|(r, s, h)| (r.clone(), *s, h.to_string()))
265 .collect();
266
267 assert_eq!(actual_hunks, expected_hunks);
268}
269
270#[cfg(test)]
271mod tests {
272 use super::*;
273 use text::Buffer;
274 use unindent::Unindent as _;
275
276 #[test]
277 fn test_buffer_diff_simple() {
278 let diff_base = "
279 one
280 two
281 three
282 "
283 .unindent();
284
285 let buffer_text = "
286 one
287 HELLO
288 three
289 "
290 .unindent();
291
292 let mut buffer = Buffer::new(0, 0, buffer_text);
293 let mut diff = BufferDiff::new();
294 smol::block_on(diff.update(&diff_base, &buffer));
295 assert_hunks(
296 diff.hunks(&buffer),
297 &buffer,
298 &diff_base,
299 &[(1..2, "two\n", "HELLO\n")],
300 );
301
302 buffer.edit([(0..0, "point five\n")]);
303 smol::block_on(diff.update(&diff_base, &buffer));
304 assert_hunks(
305 diff.hunks(&buffer),
306 &buffer,
307 &diff_base,
308 &[(0..1, "", "point five\n"), (2..3, "two\n", "HELLO\n")],
309 );
310
311 diff.clear(&buffer);
312 assert_hunks(diff.hunks(&buffer), &buffer, &diff_base, &[]);
313 }
314
315 #[test]
316 fn test_buffer_diff_range() {
317 let diff_base = "
318 one
319 two
320 three
321 four
322 five
323 six
324 seven
325 eight
326 nine
327 ten
328 "
329 .unindent();
330
331 let buffer_text = "
332 A
333 one
334 B
335 two
336 C
337 three
338 HELLO
339 four
340 five
341 SIXTEEN
342 seven
343 eight
344 WORLD
345 nine
346
347 ten
348
349 "
350 .unindent();
351
352 let buffer = Buffer::new(0, 0, buffer_text);
353 let mut diff = BufferDiff::new();
354 smol::block_on(diff.update(&diff_base, &buffer));
355 assert_eq!(diff.hunks(&buffer).count(), 8);
356
357 assert_hunks(
358 diff.hunks_in_range(7..12, &buffer, false),
359 &buffer,
360 &diff_base,
361 &[
362 (6..7, "", "HELLO\n"),
363 (9..10, "six\n", "SIXTEEN\n"),
364 (12..13, "", "WORLD\n"),
365 ],
366 );
367 }
368}