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 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 = iter::from_fn(move || {
123 cursor.next(buffer);
124 cursor.item()
125 })
126 .flat_map(move |hunk| {
127 [
128 (
129 &hunk.buffer_range.start,
130 (hunk.buffer_range.start, hunk.diff_base_byte_range.start),
131 ),
132 (
133 &hunk.buffer_range.end,
134 (hunk.buffer_range.end, hunk.diff_base_byte_range.end),
135 ),
136 ]
137 });
138
139 let mut summaries = buffer.summaries_for_anchors_with_payload::<Point, _, _>(anchor_iter);
140 iter::from_fn(move || {
141 let (start_point, (start_anchor, start_base)) = summaries.next()?;
142 let (mut end_point, (mut end_anchor, end_base)) = summaries.next()?;
143
144 if end_point.column > 0 {
145 end_point.row += 1;
146 end_point.column = 0;
147 end_anchor = buffer.anchor_before(end_point);
148 }
149
150 Some(DiffHunk {
151 row_range: start_point.row..end_point.row,
152 diff_base_byte_range: start_base..end_base,
153 buffer_range: start_anchor..end_anchor,
154 })
155 })
156 }
157
158 pub fn hunks_intersecting_range_rev<'a>(
159 &'a self,
160 range: Range<Anchor>,
161 buffer: &'a BufferSnapshot,
162 ) -> impl 'a + Iterator<Item = DiffHunk> {
163 let mut cursor = self
164 .tree
165 .filter::<_, DiffHunkSummary>(buffer, move |summary| {
166 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
167 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
168 !before_start && !after_end
169 });
170
171 iter::from_fn(move || {
172 cursor.prev(buffer);
173
174 let hunk = cursor.item()?;
175 let range = hunk.buffer_range.to_point(buffer);
176 let end_row = if range.end.column > 0 {
177 range.end.row + 1
178 } else {
179 range.end.row
180 };
181
182 Some(DiffHunk {
183 row_range: range.start.row..end_row,
184 diff_base_byte_range: hunk.diff_base_byte_range.clone(),
185 buffer_range: hunk.buffer_range.clone(),
186 })
187 })
188 }
189
190 #[cfg(test)]
191 fn clear(&mut self, buffer: &text::BufferSnapshot) {
192 self.tree = SumTree::new(buffer);
193 }
194
195 pub fn update(&mut self, diff_base: &Rope, buffer: &text::BufferSnapshot) {
196 *self = Self::build(&diff_base.to_string(), buffer);
197 }
198
199 #[cfg(test)]
200 fn hunks<'a>(&'a self, text: &'a BufferSnapshot) -> impl 'a + Iterator<Item = DiffHunk> {
201 let start = text.anchor_before(Point::new(0, 0));
202 let end = text.anchor_after(Point::new(u32::MAX, u32::MAX));
203 self.hunks_intersecting_range(start..end, text)
204 }
205
206 fn diff<'a>(head: &'a str, current: &'a str) -> Option<GitPatch<'a>> {
207 let mut options = GitOptions::default();
208 options.context_lines(0);
209
210 let patch = GitPatch::from_buffers(
211 head.as_bytes(),
212 None,
213 current.as_bytes(),
214 None,
215 Some(&mut options),
216 );
217
218 match patch {
219 Ok(patch) => Some(patch),
220
221 Err(err) => {
222 log::error!("`GitPatch::from_buffers` failed: {}", err);
223 None
224 }
225 }
226 }
227
228 fn process_patch_hunk(
229 patch: &GitPatch<'_>,
230 hunk_index: usize,
231 buffer: &text::BufferSnapshot,
232 buffer_row_divergence: &mut i64,
233 ) -> InternalDiffHunk {
234 let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
235 assert!(line_item_count > 0);
236
237 let mut first_deletion_buffer_row: Option<u32> = None;
238 let mut buffer_row_range: Option<Range<u32>> = None;
239 let mut diff_base_byte_range: Option<Range<usize>> = None;
240
241 for line_index in 0..line_item_count {
242 let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
243 let kind = line.origin_value();
244 let content_offset = line.content_offset() as isize;
245 let content_len = line.content().len() as isize;
246
247 if kind == GitDiffLineType::Addition {
248 *buffer_row_divergence += 1;
249 let row = line.new_lineno().unwrap().saturating_sub(1);
250
251 match &mut buffer_row_range {
252 Some(buffer_row_range) => buffer_row_range.end = row + 1,
253 None => buffer_row_range = Some(row..row + 1),
254 }
255 }
256
257 if kind == GitDiffLineType::Deletion {
258 let end = content_offset + content_len;
259
260 match &mut diff_base_byte_range {
261 Some(head_byte_range) => head_byte_range.end = end as usize,
262 None => diff_base_byte_range = Some(content_offset as usize..end as usize),
263 }
264
265 if first_deletion_buffer_row.is_none() {
266 let old_row = line.old_lineno().unwrap().saturating_sub(1);
267 let row = old_row as i64 + *buffer_row_divergence;
268 first_deletion_buffer_row = Some(row as u32);
269 }
270
271 *buffer_row_divergence -= 1;
272 }
273 }
274
275 //unwrap_or deletion without addition
276 let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
277 //we cannot have an addition-less hunk without deletion(s) or else there would be no hunk
278 let row = first_deletion_buffer_row.unwrap();
279 row..row
280 });
281
282 //unwrap_or addition without deletion
283 let diff_base_byte_range = diff_base_byte_range.unwrap_or(0..0);
284
285 let start = Point::new(buffer_row_range.start, 0);
286 let end = Point::new(buffer_row_range.end, 0);
287 let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
288 InternalDiffHunk {
289 buffer_range,
290 diff_base_byte_range,
291 }
292 }
293}
294
295/// Range (crossing new lines), old, new
296#[cfg(any(test, feature = "test-support"))]
297#[track_caller]
298pub fn assert_hunks<Iter>(
299 diff_hunks: Iter,
300 buffer: &BufferSnapshot,
301 diff_base: &str,
302 expected_hunks: &[(Range<u32>, &str, &str)],
303) where
304 Iter: Iterator<Item = DiffHunk>,
305{
306 let actual_hunks = diff_hunks
307 .map(|hunk| {
308 (
309 hunk.row_range.clone(),
310 &diff_base[hunk.diff_base_byte_range],
311 buffer
312 .text_for_range(
313 Point::new(hunk.row_range.start, 0)..Point::new(hunk.row_range.end, 0),
314 )
315 .collect::<String>(),
316 )
317 })
318 .collect::<Vec<_>>();
319
320 let expected_hunks: Vec<_> = expected_hunks
321 .iter()
322 .map(|(r, s, h)| (r.clone(), *s, h.to_string()))
323 .collect();
324
325 assert_eq!(actual_hunks, expected_hunks);
326}
327
328#[cfg(test)]
329mod tests {
330 use std::assert_eq;
331
332 use super::*;
333 use text::{Buffer, BufferId};
334 use unindent::Unindent as _;
335
336 #[test]
337 fn test_buffer_diff_simple() {
338 let diff_base = "
339 one
340 two
341 three
342 "
343 .unindent();
344 let diff_base_rope = Rope::from(diff_base.clone());
345
346 let buffer_text = "
347 one
348 HELLO
349 three
350 "
351 .unindent();
352
353 let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), buffer_text);
354 let mut diff = BufferDiff::new(&buffer);
355 diff.update(&diff_base_rope, &buffer);
356 assert_hunks(
357 diff.hunks(&buffer),
358 &buffer,
359 &diff_base,
360 &[(1..2, "two\n", "HELLO\n")],
361 );
362
363 buffer.edit([(0..0, "point five\n")]);
364 diff.update(&diff_base_rope, &buffer);
365 assert_hunks(
366 diff.hunks(&buffer),
367 &buffer,
368 &diff_base,
369 &[(0..1, "", "point five\n"), (2..3, "two\n", "HELLO\n")],
370 );
371
372 diff.clear(&buffer);
373 assert_hunks(diff.hunks(&buffer), &buffer, &diff_base, &[]);
374 }
375
376 #[test]
377 fn test_buffer_diff_range() {
378 let diff_base = "
379 one
380 two
381 three
382 four
383 five
384 six
385 seven
386 eight
387 nine
388 ten
389 "
390 .unindent();
391 let diff_base_rope = Rope::from(diff_base.clone());
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(&buffer);
416 diff.update(&diff_base_rope, &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}