1use rope::Rope;
2use std::{iter, ops::Range};
3use sum_tree::SumTree;
4use text::{Anchor, BufferSnapshot, OffsetRangeExt, Point};
5
6pub use git2 as libgit;
7use libgit::{DiffLineType as GitDiffLineType, DiffOptions as GitOptions, Patch as GitPatch};
8
9#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
10pub enum DiffHunkStatus {
11 Added,
12 Modified,
13 Removed,
14}
15
16/// A diff hunk resolved to rows in the buffer.
17#[derive(Debug, Clone, PartialEq, Eq)]
18pub struct DiffHunk {
19 /// The buffer range, expressed in terms of rows.
20 pub row_range: Range<u32>,
21 /// The range in the buffer to which this hunk corresponds.
22 pub buffer_range: Range<Anchor>,
23 /// The range in the buffer's diff base text to which this hunk corresponds.
24 pub diff_base_byte_range: Range<usize>,
25}
26
27/// We store [`InternalDiffHunk`]s internally so we don't need to store the additional row range.
28#[derive(Debug, Clone)]
29struct InternalDiffHunk {
30 buffer_range: Range<Anchor>,
31 diff_base_byte_range: Range<usize>,
32}
33
34impl sum_tree::Item for InternalDiffHunk {
35 type Summary = DiffHunkSummary;
36
37 fn summary(&self, _cx: &text::BufferSnapshot) -> Self::Summary {
38 DiffHunkSummary {
39 buffer_range: self.buffer_range.clone(),
40 }
41 }
42}
43
44#[derive(Debug, Default, Clone)]
45pub struct DiffHunkSummary {
46 buffer_range: Range<Anchor>,
47}
48
49impl sum_tree::Summary for DiffHunkSummary {
50 type Context = text::BufferSnapshot;
51
52 fn zero(_cx: &Self::Context) -> Self {
53 Default::default()
54 }
55
56 fn add_summary(&mut self, other: &Self, buffer: &Self::Context) {
57 self.buffer_range.start = self
58 .buffer_range
59 .start
60 .min(&other.buffer_range.start, buffer);
61 self.buffer_range.end = self.buffer_range.end.max(&other.buffer_range.end, buffer);
62 }
63}
64
65#[derive(Debug, Clone)]
66pub struct BufferDiff {
67 tree: SumTree<InternalDiffHunk>,
68}
69
70impl BufferDiff {
71 pub fn new(buffer: &BufferSnapshot) -> BufferDiff {
72 BufferDiff {
73 tree: SumTree::new(buffer),
74 }
75 }
76
77 pub async fn build(diff_base: &str, buffer: &text::BufferSnapshot) -> Self {
78 let mut tree = SumTree::new(buffer);
79
80 let buffer_text = buffer.as_rope().to_string();
81 let patch = Self::diff(diff_base, &buffer_text);
82
83 if let Some(patch) = patch {
84 let mut divergence = 0;
85 for hunk_index in 0..patch.num_hunks() {
86 let hunk = Self::process_patch_hunk(&patch, hunk_index, buffer, &mut divergence);
87 tree.push(hunk, buffer);
88 }
89 }
90
91 Self { tree }
92 }
93
94 pub fn is_empty(&self) -> bool {
95 self.tree.is_empty()
96 }
97
98 pub fn hunks_in_row_range<'a>(
99 &'a self,
100 range: Range<u32>,
101 buffer: &'a BufferSnapshot,
102 ) -> impl 'a + Iterator<Item = DiffHunk> {
103 let start = buffer.anchor_before(Point::new(range.start, 0));
104 let end = buffer.anchor_after(Point::new(range.end, 0));
105
106 self.hunks_intersecting_range(start..end, buffer)
107 }
108
109 pub fn hunks_intersecting_range<'a>(
110 &'a self,
111 range: Range<Anchor>,
112 buffer: &'a BufferSnapshot,
113 ) -> impl 'a + Iterator<Item = DiffHunk> {
114 let mut cursor = self
115 .tree
116 .filter::<_, DiffHunkSummary>(buffer, move |summary| {
117 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
118 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
119 !before_start && !after_end
120 });
121
122 let anchor_iter = std::iter::from_fn(move || {
123 cursor.next(buffer);
124 cursor.item()
125 })
126 .flat_map(move |hunk| {
127 [
128 (&hunk.buffer_range.start, hunk.diff_base_byte_range.start),
129 (&hunk.buffer_range.end, hunk.diff_base_byte_range.end),
130 ]
131 .into_iter()
132 });
133
134 let mut summaries = buffer.summaries_for_anchors_with_payload::<Point, _, _>(anchor_iter);
135 iter::from_fn(move || {
136 let (start_point, start_base) = summaries.next()?;
137 let (mut end_point, end_base) = summaries.next()?;
138
139 if end_point.column > 0 {
140 end_point.row += 1;
141 end_point.column = 0;
142 }
143
144 Some(DiffHunk {
145 row_range: start_point.row..end_point.row,
146 diff_base_byte_range: start_base..end_base,
147 buffer_range: buffer.anchor_before(start_point)..buffer.anchor_after(end_point),
148 })
149 })
150 }
151
152 pub fn hunks_intersecting_range_rev<'a>(
153 &'a self,
154 range: Range<Anchor>,
155 buffer: &'a BufferSnapshot,
156 ) -> impl 'a + Iterator<Item = DiffHunk> {
157 let mut cursor = self
158 .tree
159 .filter::<_, DiffHunkSummary>(buffer, move |summary| {
160 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
161 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
162 !before_start && !after_end
163 });
164
165 std::iter::from_fn(move || {
166 cursor.prev(buffer);
167
168 let hunk = cursor.item()?;
169 let range = hunk.buffer_range.to_point(buffer);
170 let end_row = if range.end.column > 0 {
171 range.end.row + 1
172 } else {
173 range.end.row
174 };
175
176 Some(DiffHunk {
177 row_range: range.start.row..end_row,
178 diff_base_byte_range: hunk.diff_base_byte_range.clone(),
179 buffer_range: hunk.buffer_range.clone(),
180 })
181 })
182 }
183
184 #[cfg(test)]
185 fn clear(&mut self, buffer: &text::BufferSnapshot) {
186 self.tree = SumTree::new(buffer);
187 }
188
189 pub async fn update(&mut self, diff_base: &Rope, buffer: &text::BufferSnapshot) {
190 *self = Self::build(&diff_base.to_string(), buffer).await;
191 }
192
193 #[cfg(test)]
194 fn hunks<'a>(&'a self, text: &'a BufferSnapshot) -> impl 'a + Iterator<Item = DiffHunk> {
195 let start = text.anchor_before(Point::new(0, 0));
196 let end = text.anchor_after(Point::new(u32::MAX, u32::MAX));
197 self.hunks_intersecting_range(start..end, text)
198 }
199
200 fn diff<'a>(head: &'a str, current: &'a str) -> Option<GitPatch<'a>> {
201 let mut options = GitOptions::default();
202 options.context_lines(0);
203
204 let patch = GitPatch::from_buffers(
205 head.as_bytes(),
206 None,
207 current.as_bytes(),
208 None,
209 Some(&mut options),
210 );
211
212 match patch {
213 Ok(patch) => Some(patch),
214
215 Err(err) => {
216 log::error!("`GitPatch::from_buffers` failed: {}", err);
217 None
218 }
219 }
220 }
221
222 fn process_patch_hunk(
223 patch: &GitPatch<'_>,
224 hunk_index: usize,
225 buffer: &text::BufferSnapshot,
226 buffer_row_divergence: &mut i64,
227 ) -> InternalDiffHunk {
228 let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
229 assert!(line_item_count > 0);
230
231 let mut first_deletion_buffer_row: Option<u32> = None;
232 let mut buffer_row_range: Option<Range<u32>> = None;
233 let mut diff_base_byte_range: Option<Range<usize>> = None;
234
235 for line_index in 0..line_item_count {
236 let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
237 let kind = line.origin_value();
238 let content_offset = line.content_offset() as isize;
239 let content_len = line.content().len() as isize;
240
241 if kind == GitDiffLineType::Addition {
242 *buffer_row_divergence += 1;
243 let row = line.new_lineno().unwrap().saturating_sub(1);
244
245 match &mut buffer_row_range {
246 Some(buffer_row_range) => buffer_row_range.end = row + 1,
247 None => buffer_row_range = Some(row..row + 1),
248 }
249 }
250
251 if kind == GitDiffLineType::Deletion {
252 let end = content_offset + content_len;
253
254 match &mut diff_base_byte_range {
255 Some(head_byte_range) => head_byte_range.end = end as usize,
256 None => diff_base_byte_range = Some(content_offset as usize..end as usize),
257 }
258
259 if first_deletion_buffer_row.is_none() {
260 let old_row = line.old_lineno().unwrap().saturating_sub(1);
261 let row = old_row as i64 + *buffer_row_divergence;
262 first_deletion_buffer_row = Some(row as u32);
263 }
264
265 *buffer_row_divergence -= 1;
266 }
267 }
268
269 //unwrap_or deletion without addition
270 let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
271 //we cannot have an addition-less hunk without deletion(s) or else there would be no hunk
272 let row = first_deletion_buffer_row.unwrap();
273 row..row
274 });
275
276 //unwrap_or addition without deletion
277 let diff_base_byte_range = diff_base_byte_range.unwrap_or(0..0);
278
279 let start = Point::new(buffer_row_range.start, 0);
280 let end = Point::new(buffer_row_range.end, 0);
281 let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
282 InternalDiffHunk {
283 buffer_range,
284 diff_base_byte_range,
285 }
286 }
287}
288
289/// Range (crossing new lines), old, new
290#[cfg(any(test, feature = "test-support"))]
291#[track_caller]
292pub fn assert_hunks<Iter>(
293 diff_hunks: Iter,
294 buffer: &BufferSnapshot,
295 diff_base: &str,
296 expected_hunks: &[(Range<u32>, &str, &str)],
297) where
298 Iter: Iterator<Item = DiffHunk>,
299{
300 let actual_hunks = diff_hunks
301 .map(|hunk| {
302 (
303 hunk.row_range.clone(),
304 &diff_base[hunk.diff_base_byte_range],
305 buffer
306 .text_for_range(
307 Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
308 )
309 .collect::<String>(),
310 )
311 })
312 .collect::<Vec<_>>();
313
314 let expected_hunks: Vec<_> = expected_hunks
315 .iter()
316 .map(|(r, s, h)| (r.clone(), *s, h.to_string()))
317 .collect();
318
319 assert_eq!(actual_hunks, expected_hunks);
320}
321
322#[cfg(test)]
323mod tests {
324 use std::assert_eq;
325
326 use super::*;
327 use text::{Buffer, BufferId};
328 use unindent::Unindent as _;
329
330 #[test]
331 fn test_buffer_diff_simple() {
332 let diff_base = "
333 one
334 two
335 three
336 "
337 .unindent();
338 let diff_base_rope = Rope::from(diff_base.clone());
339
340 let buffer_text = "
341 one
342 HELLO
343 three
344 "
345 .unindent();
346
347 let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), buffer_text);
348 let mut diff = BufferDiff::new(&buffer);
349 smol::block_on(diff.update(&diff_base_rope, &buffer));
350 assert_hunks(
351 diff.hunks(&buffer),
352 &buffer,
353 &diff_base,
354 &[(1..2, "two\n", "HELLO\n")],
355 );
356
357 buffer.edit([(0..0, "point five\n")]);
358 smol::block_on(diff.update(&diff_base_rope, &buffer));
359 assert_hunks(
360 diff.hunks(&buffer),
361 &buffer,
362 &diff_base,
363 &[(0..1, "", "point five\n"), (2..3, "two\n", "HELLO\n")],
364 );
365
366 diff.clear(&buffer);
367 assert_hunks(diff.hunks(&buffer), &buffer, &diff_base, &[]);
368 }
369
370 #[test]
371 fn test_buffer_diff_range() {
372 let diff_base = "
373 one
374 two
375 three
376 four
377 five
378 six
379 seven
380 eight
381 nine
382 ten
383 "
384 .unindent();
385 let diff_base_rope = Rope::from(diff_base.clone());
386
387 let buffer_text = "
388 A
389 one
390 B
391 two
392 C
393 three
394 HELLO
395 four
396 five
397 SIXTEEN
398 seven
399 eight
400 WORLD
401 nine
402
403 ten
404
405 "
406 .unindent();
407
408 let buffer = Buffer::new(0, BufferId::new(1).unwrap(), buffer_text);
409 let mut diff = BufferDiff::new(&buffer);
410 smol::block_on(diff.update(&diff_base_rope, &buffer));
411 assert_eq!(diff.hunks(&buffer).count(), 8);
412
413 assert_hunks(
414 diff.hunks_in_row_range(7..12, &buffer),
415 &buffer,
416 &diff_base,
417 &[
418 (6..7, "", "HELLO\n"),
419 (9..10, "six\n", "SIXTEEN\n"),
420 (12..13, "", "WORLD\n"),
421 ],
422 );
423 }
424}