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_row_range<'a>(
75 &'a self,
76 range: Range<u32>,
77 buffer: &'a BufferSnapshot,
78 reversed: bool,
79 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
80 let start = buffer.anchor_before(Point::new(range.start, 0));
81 let end = buffer.anchor_after(Point::new(range.end, 0));
82 self.hunks_intersecting_range(start..end, buffer, reversed)
83 }
84
85 pub fn hunks_intersecting_range<'a>(
86 &'a self,
87 range: Range<Anchor>,
88 buffer: &'a BufferSnapshot,
89 reversed: bool,
90 ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
91 let mut cursor = self.tree.filter::<_, DiffHunkSummary>(move |summary| {
92 let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
93 let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
94 !before_start && !after_end
95 });
96
97 std::iter::from_fn(move || {
98 if reversed {
99 cursor.prev(buffer);
100 } else {
101 cursor.next(buffer);
102 }
103
104 let hunk = cursor.item()?;
105
106 let range = hunk.buffer_range.to_point(buffer);
107 let end_row = if range.end.column > 0 {
108 range.end.row + 1
109 } else {
110 range.end.row
111 };
112
113 Some(DiffHunk {
114 buffer_range: range.start.row..end_row,
115 diff_base_byte_range: hunk.diff_base_byte_range.clone(),
116 })
117 })
118 }
119
120 pub fn clear(&mut self, buffer: &text::BufferSnapshot) {
121 self.last_buffer_version = Some(buffer.version().clone());
122 self.tree = SumTree::new();
123 }
124
125 pub fn needs_update(&self, buffer: &text::BufferSnapshot) -> bool {
126 match &self.last_buffer_version {
127 Some(last) => buffer.version().changed_since(last),
128 None => true,
129 }
130 }
131
132 pub async fn update(&mut self, diff_base: &str, buffer: &text::BufferSnapshot) {
133 let mut tree = SumTree::new();
134
135 let buffer_text = buffer.as_rope().to_string();
136 let patch = Self::diff(&diff_base, &buffer_text);
137
138 if let Some(patch) = patch {
139 let mut divergence = 0;
140 for hunk_index in 0..patch.num_hunks() {
141 let hunk = Self::process_patch_hunk(&patch, hunk_index, buffer, &mut divergence);
142 tree.push(hunk, buffer);
143 }
144 }
145
146 self.tree = tree;
147 self.last_buffer_version = Some(buffer.version().clone());
148 }
149
150 #[cfg(test)]
151 fn hunks<'a>(&'a self, text: &'a BufferSnapshot) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
152 let start = text.anchor_before(Point::new(0, 0));
153 let end = text.anchor_after(Point::new(u32::MAX, u32::MAX));
154 self.hunks_intersecting_range(start..end, text, false)
155 }
156
157 fn diff<'a>(head: &'a str, current: &'a str) -> Option<GitPatch<'a>> {
158 let mut options = GitOptions::default();
159 options.context_lines(0);
160
161 let patch = GitPatch::from_buffers(
162 head.as_bytes(),
163 None,
164 current.as_bytes(),
165 None,
166 Some(&mut options),
167 );
168
169 match patch {
170 Ok(patch) => Some(patch),
171
172 Err(err) => {
173 log::error!("`GitPatch::from_buffers` failed: {}", err);
174 None
175 }
176 }
177 }
178
179 fn process_patch_hunk<'a>(
180 patch: &GitPatch<'a>,
181 hunk_index: usize,
182 buffer: &text::BufferSnapshot,
183 buffer_row_divergence: &mut i64,
184 ) -> DiffHunk<Anchor> {
185 let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
186 assert!(line_item_count > 0);
187
188 let mut first_deletion_buffer_row: Option<u32> = None;
189 let mut buffer_row_range: Option<Range<u32>> = None;
190 let mut diff_base_byte_range: Option<Range<usize>> = None;
191
192 for line_index in 0..line_item_count {
193 let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
194 let kind = line.origin_value();
195 let content_offset = line.content_offset() as isize;
196 let content_len = line.content().len() as isize;
197
198 if kind == GitDiffLineType::Addition {
199 *buffer_row_divergence += 1;
200 let row = line.new_lineno().unwrap().saturating_sub(1);
201
202 match &mut buffer_row_range {
203 Some(buffer_row_range) => buffer_row_range.end = row + 1,
204 None => buffer_row_range = Some(row..row + 1),
205 }
206 }
207
208 if kind == GitDiffLineType::Deletion {
209 let end = content_offset + content_len;
210
211 match &mut diff_base_byte_range {
212 Some(head_byte_range) => head_byte_range.end = end as usize,
213 None => diff_base_byte_range = Some(content_offset as usize..end as usize),
214 }
215
216 if first_deletion_buffer_row.is_none() {
217 let old_row = line.old_lineno().unwrap().saturating_sub(1);
218 let row = old_row as i64 + *buffer_row_divergence;
219 first_deletion_buffer_row = Some(row as u32);
220 }
221
222 *buffer_row_divergence -= 1;
223 }
224 }
225
226 //unwrap_or deletion without addition
227 let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
228 //we cannot have an addition-less hunk without deletion(s) or else there would be no hunk
229 let row = first_deletion_buffer_row.unwrap();
230 row..row
231 });
232
233 //unwrap_or addition without deletion
234 let diff_base_byte_range = diff_base_byte_range.unwrap_or(0..0);
235
236 let start = Point::new(buffer_row_range.start, 0);
237 let end = Point::new(buffer_row_range.end, 0);
238 let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
239 DiffHunk {
240 buffer_range,
241 diff_base_byte_range,
242 }
243 }
244}
245
246/// Range (crossing new lines), old, new
247#[cfg(any(test, feature = "test-support"))]
248#[track_caller]
249pub fn assert_hunks<Iter>(
250 diff_hunks: Iter,
251 buffer: &BufferSnapshot,
252 diff_base: &str,
253 expected_hunks: &[(Range<u32>, &str, &str)],
254) where
255 Iter: Iterator<Item = DiffHunk<u32>>,
256{
257 let actual_hunks = diff_hunks
258 .map(|hunk| {
259 (
260 hunk.buffer_range.clone(),
261 &diff_base[hunk.diff_base_byte_range],
262 buffer
263 .text_for_range(
264 Point::new(hunk.buffer_range.start, 0)
265 ..Point::new(hunk.buffer_range.end, 0),
266 )
267 .collect::<String>(),
268 )
269 })
270 .collect::<Vec<_>>();
271
272 let expected_hunks: Vec<_> = expected_hunks
273 .iter()
274 .map(|(r, s, h)| (r.clone(), *s, h.to_string()))
275 .collect();
276
277 assert_eq!(actual_hunks, expected_hunks);
278}
279
280#[cfg(test)]
281mod tests {
282 use super::*;
283 use text::Buffer;
284 use unindent::Unindent as _;
285
286 #[test]
287 fn test_buffer_diff_simple() {
288 let diff_base = "
289 one
290 two
291 three
292 "
293 .unindent();
294
295 let buffer_text = "
296 one
297 HELLO
298 three
299 "
300 .unindent();
301
302 let mut buffer = Buffer::new(0, 0, buffer_text);
303 let mut diff = BufferDiff::new();
304 smol::block_on(diff.update(&diff_base, &buffer));
305 assert_hunks(
306 diff.hunks(&buffer),
307 &buffer,
308 &diff_base,
309 &[(1..2, "two\n", "HELLO\n")],
310 );
311
312 buffer.edit([(0..0, "point five\n")]);
313 smol::block_on(diff.update(&diff_base, &buffer));
314 assert_hunks(
315 diff.hunks(&buffer),
316 &buffer,
317 &diff_base,
318 &[(0..1, "", "point five\n"), (2..3, "two\n", "HELLO\n")],
319 );
320
321 diff.clear(&buffer);
322 assert_hunks(diff.hunks(&buffer), &buffer, &diff_base, &[]);
323 }
324
325 #[test]
326 fn test_buffer_diff_range() {
327 let diff_base = "
328 one
329 two
330 three
331 four
332 five
333 six
334 seven
335 eight
336 nine
337 ten
338 "
339 .unindent();
340
341 let buffer_text = "
342 A
343 one
344 B
345 two
346 C
347 three
348 HELLO
349 four
350 five
351 SIXTEEN
352 seven
353 eight
354 WORLD
355 nine
356
357 ten
358
359 "
360 .unindent();
361
362 let buffer = Buffer::new(0, 0, buffer_text);
363 let mut diff = BufferDiff::new();
364 smol::block_on(diff.update(&diff_base, &buffer));
365 assert_eq!(diff.hunks(&buffer).count(), 8);
366
367 assert_hunks(
368 diff.hunks_in_row_range(7..12, &buffer, false),
369 &buffer,
370 &diff_base,
371 &[
372 (6..7, "", "HELLO\n"),
373 (9..10, "six\n", "SIXTEEN\n"),
374 (12..13, "", "WORLD\n"),
375 ],
376 );
377 }
378}