1use std::{iter, ops::Range};
2use sum_tree::SumTree;
3use text::{Anchor, BufferId, 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/// A diff hunk, representing a range of consequent lines in a singleton buffer, associated with a generic range.
16#[derive(Debug, Clone, PartialEq, Eq)]
17pub struct DiffHunk<T> {
18 /// E.g. a range in multibuffer, that has an excerpt added, singleton buffer for which has this diff hunk.
19 /// Consider a singleton buffer with 10 lines, all of them are modified — so a corresponding diff hunk would have a range 0..10.
20 /// And a multibuffer with the excerpt of lines 2-6 from the singleton buffer.
21 /// If the multibuffer is searched for diff hunks, the associated range would be multibuffer rows, corresponding to rows 2..6 from the singleton buffer.
22 /// But the hunk range would be 0..10, same for any other excerpts from the same singleton buffer.
23 pub associated_range: Range<T>,
24 /// Singleton buffer ID this hunk belongs to.
25 pub buffer_id: BufferId,
26 /// A consequent range of lines in the singleton buffer, that were changed and produced this diff hunk.
27 pub buffer_range: Range<Anchor>,
28 /// Original singleton buffer text before the change, that was instead of the `buffer_range`.
29 pub diff_base_byte_range: Range<usize>,
30}
31
32impl DiffHunk<u32> {
33 pub fn status(&self) -> DiffHunkStatus {
34 if self.diff_base_byte_range.is_empty() {
35 DiffHunkStatus::Added
36 } else if self.associated_range.is_empty() {
37 DiffHunkStatus::Removed
38 } else {
39 DiffHunkStatus::Modified
40 }
41 }
42}
43
44impl sum_tree::Item for DiffHunk<Anchor> {
45 type Summary = DiffHunkSummary;
46
47 fn summary(&self) -> Self::Summary {
48 DiffHunkSummary {
49 buffer_range: self.associated_range.clone(),
50 }
51 }
52}
53
54#[derive(Debug, Default, Clone)]
55pub struct DiffHunkSummary {
56 buffer_range: Range<Anchor>,
57}
58
59impl sum_tree::Summary for DiffHunkSummary {
60 type Context = text::BufferSnapshot;
61
62 fn add_summary(&mut self, other: &Self, buffer: &Self::Context) {
63 self.buffer_range.start = self
64 .buffer_range
65 .start
66 .min(&other.buffer_range.start, buffer);
67 self.buffer_range.end = self.buffer_range.end.max(&other.buffer_range.end, buffer);
68 }
69}
70
71#[derive(Debug, Clone)]
72pub struct BufferDiff {
73 last_buffer_version: Option<clock::Global>,
74 tree: SumTree<DiffHunk<Anchor>>,
75}
76
77impl BufferDiff {
78 pub fn new() -> BufferDiff {
79 BufferDiff {
80 last_buffer_version: None,
81 tree: SumTree::new(),
82 }
83 }
84
85 pub fn is_empty(&self) -> bool {
86 self.tree.is_empty()
87 }
88
89 pub fn hunks_in_row_range<'a>(
90 &'a self,
91 range: Range<u32>,
92 buffer: &'a BufferSnapshot,
93 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
94 let start = buffer.anchor_before(Point::new(range.start, 0));
95 let end = buffer.anchor_after(Point::new(range.end, 0));
96
97 self.hunks_intersecting_range(start..end, buffer)
98 }
99
100 pub fn hunks_intersecting_range<'a>(
101 &'a self,
102 range: Range<Anchor>,
103 buffer: &'a BufferSnapshot,
104 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
105 let mut cursor = self.tree.filter::<_, DiffHunkSummary>(move |summary| {
106 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
107 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
108 !before_start && !after_end
109 });
110
111 let anchor_iter = std::iter::from_fn(move || {
112 cursor.next(buffer);
113 cursor.item()
114 })
115 .flat_map(move |hunk| {
116 [
117 (
118 &hunk.associated_range.start,
119 hunk.diff_base_byte_range.start,
120 ),
121 (&hunk.associated_range.end, hunk.diff_base_byte_range.end),
122 ]
123 .into_iter()
124 });
125
126 let mut summaries = buffer.summaries_for_anchors_with_payload::<Point, _, _>(anchor_iter);
127 iter::from_fn(move || {
128 let (start_point, start_base) = summaries.next()?;
129 let (mut end_point, end_base) = summaries.next()?;
130
131 if end_point.column > 0 {
132 end_point.row += 1;
133 }
134
135 Some(DiffHunk {
136 associated_range: start_point.row..end_point.row,
137 diff_base_byte_range: start_base..end_base,
138 buffer_range: buffer.anchor_before(start_point)..buffer.anchor_after(end_point),
139 buffer_id: buffer.remote_id(),
140 })
141 })
142 }
143
144 pub fn hunks_intersecting_range_rev<'a>(
145 &'a self,
146 range: Range<Anchor>,
147 buffer: &'a BufferSnapshot,
148 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
149 let mut cursor = self.tree.filter::<_, DiffHunkSummary>(move |summary| {
150 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
151 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
152 !before_start && !after_end
153 });
154
155 std::iter::from_fn(move || {
156 cursor.prev(buffer);
157
158 let hunk = cursor.item()?;
159 let range = hunk.associated_range.to_point(buffer);
160 let end_row = if range.end.column > 0 {
161 range.end.row + 1
162 } else {
163 range.end.row
164 };
165
166 Some(DiffHunk {
167 associated_range: range.start.row..end_row,
168 diff_base_byte_range: hunk.diff_base_byte_range.clone(),
169 buffer_range: hunk.buffer_range.clone(),
170 buffer_id: hunk.buffer_id,
171 })
172 })
173 }
174
175 pub fn clear(&mut self, buffer: &text::BufferSnapshot) {
176 self.last_buffer_version = Some(buffer.version().clone());
177 self.tree = SumTree::new();
178 }
179
180 pub async fn update(&mut self, diff_base: &str, buffer: &text::BufferSnapshot) {
181 let mut tree = SumTree::new();
182
183 let buffer_text = buffer.as_rope().to_string();
184 let patch = Self::diff(diff_base, &buffer_text);
185
186 if let Some(patch) = patch {
187 let mut divergence = 0;
188 for hunk_index in 0..patch.num_hunks() {
189 let hunk = Self::process_patch_hunk(&patch, hunk_index, buffer, &mut divergence);
190 tree.push(hunk, buffer);
191 }
192 }
193
194 self.tree = tree;
195 self.last_buffer_version = Some(buffer.version().clone());
196 }
197
198 #[cfg(test)]
199 fn hunks<'a>(&'a self, text: &'a BufferSnapshot) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
200 let start = text.anchor_before(Point::new(0, 0));
201 let end = text.anchor_after(Point::new(u32::MAX, u32::MAX));
202 self.hunks_intersecting_range(start..end, text)
203 }
204
205 fn diff<'a>(head: &'a str, current: &'a str) -> Option<GitPatch<'a>> {
206 let mut options = GitOptions::default();
207 options.context_lines(0);
208
209 let patch = GitPatch::from_buffers(
210 head.as_bytes(),
211 None,
212 current.as_bytes(),
213 None,
214 Some(&mut options),
215 );
216
217 match patch {
218 Ok(patch) => Some(patch),
219
220 Err(err) => {
221 log::error!("`GitPatch::from_buffers` failed: {}", err);
222 None
223 }
224 }
225 }
226
227 fn process_patch_hunk(
228 patch: &GitPatch<'_>,
229 hunk_index: usize,
230 buffer: &text::BufferSnapshot,
231 buffer_row_divergence: &mut i64,
232 ) -> DiffHunk<Anchor> {
233 let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
234 assert!(line_item_count > 0);
235
236 let mut first_deletion_buffer_row: Option<u32> = None;
237 let mut buffer_row_range: Option<Range<u32>> = None;
238 let mut diff_base_byte_range: Option<Range<usize>> = None;
239
240 for line_index in 0..line_item_count {
241 let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
242 let kind = line.origin_value();
243 let content_offset = line.content_offset() as isize;
244 let content_len = line.content().len() as isize;
245
246 if kind == GitDiffLineType::Addition {
247 *buffer_row_divergence += 1;
248 let row = line.new_lineno().unwrap().saturating_sub(1);
249
250 match &mut buffer_row_range {
251 Some(buffer_row_range) => buffer_row_range.end = row + 1,
252 None => buffer_row_range = Some(row..row + 1),
253 }
254 }
255
256 if kind == GitDiffLineType::Deletion {
257 let end = content_offset + content_len;
258
259 match &mut diff_base_byte_range {
260 Some(head_byte_range) => head_byte_range.end = end as usize,
261 None => diff_base_byte_range = Some(content_offset as usize..end as usize),
262 }
263
264 if first_deletion_buffer_row.is_none() {
265 let old_row = line.old_lineno().unwrap().saturating_sub(1);
266 let row = old_row as i64 + *buffer_row_divergence;
267 first_deletion_buffer_row = Some(row as u32);
268 }
269
270 *buffer_row_divergence -= 1;
271 }
272 }
273
274 //unwrap_or deletion without addition
275 let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
276 //we cannot have an addition-less hunk without deletion(s) or else there would be no hunk
277 let row = first_deletion_buffer_row.unwrap();
278 row..row
279 });
280
281 //unwrap_or addition without deletion
282 let diff_base_byte_range = diff_base_byte_range.unwrap_or(0..0);
283
284 let start = Point::new(buffer_row_range.start, 0);
285 let end = Point::new(buffer_row_range.end, 0);
286 let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
287 DiffHunk {
288 associated_range: buffer_range.clone(),
289 buffer_range,
290 diff_base_byte_range,
291 buffer_id: buffer.remote_id(),
292 }
293 }
294}
295
296/// Range (crossing new lines), old, new
297#[cfg(any(test, feature = "test-support"))]
298#[track_caller]
299pub fn assert_hunks<Iter>(
300 diff_hunks: Iter,
301 buffer: &BufferSnapshot,
302 diff_base: &str,
303 expected_hunks: &[(Range<u32>, &str, &str)],
304) where
305 Iter: Iterator<Item = DiffHunk<u32>>,
306{
307 let actual_hunks = diff_hunks
308 .map(|hunk| {
309 (
310 hunk.associated_range.clone(),
311 &diff_base[hunk.diff_base_byte_range],
312 buffer
313 .text_for_range(
314 Point::new(hunk.associated_range.start, 0)
315 ..Point::new(hunk.associated_range.end, 0),
316 )
317 .collect::<String>(),
318 )
319 })
320 .collect::<Vec<_>>();
321
322 let expected_hunks: Vec<_> = expected_hunks
323 .iter()
324 .map(|(r, s, h)| (r.clone(), *s, h.to_string()))
325 .collect();
326
327 assert_eq!(actual_hunks, expected_hunks);
328}
329
330#[cfg(test)]
331mod tests {
332 use std::assert_eq;
333
334 use super::*;
335 use text::{Buffer, BufferId};
336 use unindent::Unindent as _;
337
338 #[test]
339 fn test_buffer_diff_simple() {
340 let diff_base = "
341 one
342 two
343 three
344 "
345 .unindent();
346
347 let buffer_text = "
348 one
349 HELLO
350 three
351 "
352 .unindent();
353
354 let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), buffer_text);
355 let mut diff = BufferDiff::new();
356 smol::block_on(diff.update(&diff_base, &buffer));
357 assert_hunks(
358 diff.hunks(&buffer),
359 &buffer,
360 &diff_base,
361 &[(1..2, "two\n", "HELLO\n")],
362 );
363
364 buffer.edit([(0..0, "point five\n")]);
365 smol::block_on(diff.update(&diff_base, &buffer));
366 assert_hunks(
367 diff.hunks(&buffer),
368 &buffer,
369 &diff_base,
370 &[(0..1, "", "point five\n"), (2..3, "two\n", "HELLO\n")],
371 );
372
373 diff.clear(&buffer);
374 assert_hunks(diff.hunks(&buffer), &buffer, &diff_base, &[]);
375 }
376
377 #[test]
378 fn test_buffer_diff_range() {
379 let diff_base = "
380 one
381 two
382 three
383 four
384 five
385 six
386 seven
387 eight
388 nine
389 ten
390 "
391 .unindent();
392
393 let buffer_text = "
394 A
395 one
396 B
397 two
398 C
399 three
400 HELLO
401 four
402 five
403 SIXTEEN
404 seven
405 eight
406 WORLD
407 nine
408
409 ten
410
411 "
412 .unindent();
413
414 let buffer = Buffer::new(0, BufferId::new(1).unwrap(), buffer_text);
415 let mut diff = BufferDiff::new();
416 smol::block_on(diff.update(&diff_base, &buffer));
417 assert_eq!(diff.hunks(&buffer).count(), 8);
418
419 assert_hunks(
420 diff.hunks_in_row_range(7..12, &buffer),
421 &buffer,
422 &diff_base,
423 &[
424 (6..7, "", "HELLO\n"),
425 (9..10, "six\n", "SIXTEEN\n"),
426 (12..13, "", "WORLD\n"),
427 ],
428 );
429 }
430}