1use anyhow::Result;
2use buffer_diff::BufferDiff;
3use gpui::{App, AppContext, AsyncApp, Context, Entity, Subscription, Task};
4use itertools::Itertools;
5use language::{
6 Anchor, Buffer, Capability, LanguageRegistry, OffsetRangeExt as _, Point, TextBuffer,
7};
8use multi_buffer::{MultiBuffer, PathKey, excerpt_context_lines};
9use std::{cmp::Reverse, ops::Range, path::Path, sync::Arc};
10use util::ResultExt;
11
12pub enum Diff {
13 Pending(PendingDiff),
14 Finalized(FinalizedDiff),
15}
16
17impl Diff {
18 pub fn finalized(
19 path: String,
20 old_text: Option<String>,
21 new_text: String,
22 language_registry: Arc<LanguageRegistry>,
23 cx: &mut Context<Self>,
24 ) -> Self {
25 let multibuffer = cx.new(|_cx| MultiBuffer::without_headers(Capability::ReadOnly));
26 let new_buffer = cx.new(|cx| Buffer::local(new_text, cx));
27 let base_text = old_text.clone().unwrap_or(String::new()).into();
28 let task = cx.spawn({
29 let multibuffer = multibuffer.clone();
30 let path = path.clone();
31 let buffer = new_buffer.clone();
32 async move |_, cx| {
33 let language = language_registry
34 .load_language_for_file_path(Path::new(&path))
35 .await
36 .log_err();
37
38 buffer.update(cx, |buffer, cx| buffer.set_language(language.clone(), cx));
39 buffer.update(cx, |buffer, _| buffer.parsing_idle()).await;
40
41 let diff = build_buffer_diff(
42 old_text.unwrap_or("".into()).into(),
43 &buffer,
44 Some(language_registry.clone()),
45 cx,
46 )
47 .await?;
48
49 multibuffer.update(cx, |multibuffer, cx| {
50 let hunk_ranges = {
51 let buffer = buffer.read(cx);
52 diff.read(cx)
53 .snapshot(cx)
54 .hunks_intersecting_range(
55 Anchor::min_for_buffer(buffer.remote_id())
56 ..Anchor::max_for_buffer(buffer.remote_id()),
57 buffer,
58 )
59 .map(|diff_hunk| diff_hunk.buffer_range.to_point(buffer))
60 .collect::<Vec<_>>()
61 };
62
63 multibuffer.set_excerpts_for_path(
64 PathKey::for_buffer(&buffer, cx),
65 buffer.clone(),
66 hunk_ranges,
67 excerpt_context_lines(cx),
68 cx,
69 );
70 multibuffer.add_diff(diff, cx);
71 });
72
73 anyhow::Ok(())
74 }
75 });
76
77 Self::Finalized(FinalizedDiff {
78 multibuffer,
79 path,
80 base_text,
81 new_buffer,
82 _update_diff: task,
83 })
84 }
85
86 pub fn new(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
87 let buffer_text_snapshot = buffer.read(cx).text_snapshot();
88 let language = buffer.read(cx).language().cloned();
89 let language_registry = buffer.read(cx).language_registry();
90 let buffer_diff = cx.new(|cx| {
91 let mut diff = BufferDiff::new_unchanged(&buffer_text_snapshot, cx);
92 diff.language_changed(language.clone(), language_registry.clone(), cx);
93 let secondary_diff = cx.new(|cx| {
94 // For the secondary diff buffer we skip assigning the language as we do not really need to perform any syntax highlighting on
95 // it. As a result, by skipping it we are potentially shaving off a lot of RSS plus we get a snappier feel for large diff
96 // view multibuffers.
97 BufferDiff::new_unchanged(&buffer_text_snapshot, cx)
98 });
99 diff.set_secondary_diff(secondary_diff);
100 diff
101 });
102
103 let multibuffer = cx.new(|cx| {
104 let mut multibuffer = MultiBuffer::without_headers(Capability::ReadOnly);
105 multibuffer.add_diff(buffer_diff.clone(), cx);
106 multibuffer
107 });
108
109 Self::Pending(PendingDiff {
110 multibuffer,
111 base_text: Arc::from(buffer_text_snapshot.text().as_str()),
112 _subscription: cx.observe(&buffer, |this, _, cx| {
113 if let Diff::Pending(diff) = this {
114 diff.update(cx);
115 }
116 }),
117 new_buffer: buffer,
118 diff: buffer_diff,
119 revealed_ranges: Vec::new(),
120 update_diff: Task::ready(Ok(())),
121 })
122 }
123
124 pub fn reveal_range(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
125 if let Self::Pending(diff) = self {
126 diff.reveal_range(range, cx);
127 }
128 }
129
130 pub fn finalize(&mut self, cx: &mut Context<Self>) {
131 if let Self::Pending(diff) = self {
132 *self = Self::Finalized(diff.finalize(cx));
133 }
134 }
135
136 /// Returns the original text before any edits were applied.
137 pub fn base_text(&self) -> &Arc<str> {
138 match self {
139 Self::Pending(PendingDiff { base_text, .. }) => base_text,
140 Self::Finalized(FinalizedDiff { base_text, .. }) => base_text,
141 }
142 }
143
144 /// Returns the buffer being edited (for pending diffs) or the snapshot buffer (for finalized diffs).
145 pub fn buffer(&self) -> &Entity<Buffer> {
146 match self {
147 Self::Pending(PendingDiff { new_buffer, .. }) => new_buffer,
148 Self::Finalized(FinalizedDiff { new_buffer, .. }) => new_buffer,
149 }
150 }
151
152 pub fn multibuffer(&self) -> &Entity<MultiBuffer> {
153 match self {
154 Self::Pending(PendingDiff { multibuffer, .. }) => multibuffer,
155 Self::Finalized(FinalizedDiff { multibuffer, .. }) => multibuffer,
156 }
157 }
158
159 pub fn to_markdown(&self, cx: &App) -> String {
160 let buffer_text = self
161 .multibuffer()
162 .read(cx)
163 .all_buffers()
164 .iter()
165 .map(|buffer| buffer.read(cx).text())
166 .join("\n");
167 let path = match self {
168 Diff::Pending(PendingDiff {
169 new_buffer: buffer, ..
170 }) => buffer
171 .read(cx)
172 .file()
173 .map(|file| file.path().display(file.path_style(cx))),
174 Diff::Finalized(FinalizedDiff { path, .. }) => Some(path.as_str().into()),
175 };
176 format!(
177 "Diff: {}\n```\n{}\n```\n",
178 path.unwrap_or("untitled".into()),
179 buffer_text
180 )
181 }
182
183 pub fn has_revealed_range(&self, cx: &App) -> bool {
184 self.multibuffer().read(cx).paths().next().is_some()
185 }
186
187 pub fn needs_update(&self, old_text: &str, new_text: &str, cx: &App) -> bool {
188 match self {
189 Diff::Pending(PendingDiff {
190 base_text,
191 new_buffer,
192 ..
193 }) => {
194 base_text.as_ref() != old_text
195 || !new_buffer.read(cx).as_rope().chunks().equals_str(new_text)
196 }
197 Diff::Finalized(FinalizedDiff {
198 base_text,
199 new_buffer,
200 ..
201 }) => {
202 base_text.as_ref() != old_text
203 || !new_buffer.read(cx).as_rope().chunks().equals_str(new_text)
204 }
205 }
206 }
207}
208
209pub struct PendingDiff {
210 multibuffer: Entity<MultiBuffer>,
211 base_text: Arc<str>,
212 new_buffer: Entity<Buffer>,
213 diff: Entity<BufferDiff>,
214 revealed_ranges: Vec<Range<Anchor>>,
215 _subscription: Subscription,
216 update_diff: Task<Result<()>>,
217}
218
219impl PendingDiff {
220 pub fn update(&mut self, cx: &mut Context<Diff>) {
221 let buffer = self.new_buffer.clone();
222 let buffer_diff = self.diff.clone();
223 let base_text = self.base_text.clone();
224 self.update_diff = cx.spawn(async move |diff, cx| {
225 let text_snapshot = buffer.read_with(cx, |buffer, _| buffer.text_snapshot());
226 let language = buffer.read_with(cx, |buffer, _| buffer.language().cloned());
227 let update = buffer_diff
228 .update(cx, |diff, cx| {
229 diff.update_diff(
230 text_snapshot.clone(),
231 Some(base_text.clone()),
232 None,
233 language,
234 cx,
235 )
236 })
237 .await;
238 let (task1, task2) = buffer_diff.update(cx, |diff, cx| {
239 let task1 = diff.set_snapshot(update.clone(), &text_snapshot, cx);
240 let task2 = diff
241 .secondary_diff()
242 .unwrap()
243 .update(cx, |diff, cx| diff.set_snapshot(update, &text_snapshot, cx));
244 (task1, task2)
245 });
246 task1.await;
247 task2.await;
248 diff.update(cx, |diff, cx| {
249 if let Diff::Pending(diff) = diff {
250 diff.update_visible_ranges(cx);
251 }
252 })
253 });
254 }
255
256 pub fn reveal_range(&mut self, range: Range<Anchor>, cx: &mut Context<Diff>) {
257 self.revealed_ranges.push(range);
258 self.update_visible_ranges(cx);
259 }
260
261 fn finalize(&self, cx: &mut Context<Diff>) -> FinalizedDiff {
262 let ranges = self.excerpt_ranges(cx);
263 let base_text = self.base_text.clone();
264 let new_buffer = self.new_buffer.read(cx);
265 let language_registry = new_buffer.language_registry();
266
267 let path = new_buffer
268 .file()
269 .map(|file| file.path().display(file.path_style(cx)))
270 .unwrap_or("untitled".into())
271 .into();
272 let replica_id = new_buffer.replica_id();
273
274 // Replace the buffer in the multibuffer with the snapshot
275 let buffer = cx.new(|cx| {
276 let language = self.new_buffer.read(cx).language().cloned();
277 let buffer = TextBuffer::new_normalized(
278 replica_id,
279 cx.entity_id().as_non_zero_u64().into(),
280 self.new_buffer.read(cx).line_ending(),
281 self.new_buffer.read(cx).as_rope().clone(),
282 );
283 let mut buffer = Buffer::build(buffer, None, Capability::ReadWrite);
284 buffer.set_language(language, cx);
285 buffer
286 });
287
288 let buffer_diff = cx.spawn({
289 let buffer = buffer.clone();
290 async move |_this, cx| {
291 buffer.update(cx, |buffer, _| buffer.parsing_idle()).await;
292 build_buffer_diff(base_text, &buffer, language_registry, cx).await
293 }
294 });
295
296 let update_diff = cx.spawn(async move |this, cx| {
297 let buffer_diff = buffer_diff.await?;
298 this.update(cx, |this, cx| {
299 this.multibuffer().update(cx, |multibuffer, cx| {
300 let path_key = PathKey::for_buffer(&buffer, cx);
301 multibuffer.clear(cx);
302 multibuffer.set_excerpts_for_path(
303 path_key,
304 buffer,
305 ranges,
306 excerpt_context_lines(cx),
307 cx,
308 );
309 multibuffer.add_diff(buffer_diff.clone(), cx);
310 });
311
312 cx.notify();
313 })
314 });
315
316 FinalizedDiff {
317 path,
318 base_text: self.base_text.clone(),
319 multibuffer: self.multibuffer.clone(),
320 new_buffer: self.new_buffer.clone(),
321 _update_diff: update_diff,
322 }
323 }
324
325 fn update_visible_ranges(&mut self, cx: &mut Context<Diff>) {
326 let ranges = self.excerpt_ranges(cx);
327 self.multibuffer.update(cx, |multibuffer, cx| {
328 multibuffer.set_excerpts_for_path(
329 PathKey::for_buffer(&self.new_buffer, cx),
330 self.new_buffer.clone(),
331 ranges,
332 excerpt_context_lines(cx),
333 cx,
334 );
335 let end = multibuffer.len(cx);
336 Some(multibuffer.snapshot(cx).offset_to_point(end).row + 1)
337 });
338 cx.notify();
339 }
340
341 fn excerpt_ranges(&self, cx: &App) -> Vec<Range<Point>> {
342 let buffer = self.new_buffer.read(cx);
343 let mut ranges = self
344 .diff
345 .read(cx)
346 .snapshot(cx)
347 .hunks_intersecting_range(
348 Anchor::min_for_buffer(buffer.remote_id())
349 ..Anchor::max_for_buffer(buffer.remote_id()),
350 buffer,
351 )
352 .map(|diff_hunk| diff_hunk.buffer_range.to_point(buffer))
353 .collect::<Vec<_>>();
354 ranges.extend(
355 self.revealed_ranges
356 .iter()
357 .map(|range| range.to_point(buffer)),
358 );
359 ranges.sort_unstable_by_key(|range| (range.start, Reverse(range.end)));
360
361 // Merge adjacent ranges
362 let mut ranges = ranges.into_iter().peekable();
363 let mut merged_ranges = Vec::new();
364 while let Some(mut range) = ranges.next() {
365 while let Some(next_range) = ranges.peek() {
366 if range.end >= next_range.start {
367 range.end = range.end.max(next_range.end);
368 ranges.next();
369 } else {
370 break;
371 }
372 }
373
374 merged_ranges.push(range);
375 }
376 merged_ranges
377 }
378}
379
380pub struct FinalizedDiff {
381 path: String,
382 base_text: Arc<str>,
383 new_buffer: Entity<Buffer>,
384 multibuffer: Entity<MultiBuffer>,
385 _update_diff: Task<Result<()>>,
386}
387
388async fn build_buffer_diff(
389 old_text: Arc<str>,
390 buffer: &Entity<Buffer>,
391 language_registry: Option<Arc<LanguageRegistry>>,
392 cx: &mut AsyncApp,
393) -> Result<Entity<BufferDiff>> {
394 let language = cx.update(|cx| buffer.read(cx).language().cloned());
395 let text_snapshot = cx.update(|cx| buffer.read(cx).text_snapshot());
396 let buffer = cx.update(|cx| buffer.read(cx).snapshot());
397
398 let secondary_diff = cx.new(|cx| BufferDiff::new(&buffer, cx));
399
400 let update = secondary_diff
401 .update(cx, |secondary_diff, cx| {
402 secondary_diff.update_diff(
403 text_snapshot.clone(),
404 Some(old_text),
405 Some(false),
406 language.clone(),
407 cx,
408 )
409 })
410 .await;
411
412 secondary_diff
413 .update(cx, |secondary_diff, cx| {
414 secondary_diff.set_snapshot(update.clone(), &buffer, cx)
415 })
416 .await;
417
418 let diff = cx.new(|cx| BufferDiff::new(&buffer, cx));
419 diff.update(cx, |diff, cx| {
420 diff.language_changed(language, language_registry, cx);
421 diff.set_secondary_diff(secondary_diff);
422 diff.set_snapshot(update.clone(), &buffer, cx)
423 })
424 .await;
425 Ok(diff)
426}
427
428#[cfg(test)]
429mod tests {
430 use gpui::{AppContext as _, TestAppContext};
431 use language::Buffer;
432
433 use crate::Diff;
434
435 #[gpui::test]
436 async fn test_pending_diff(cx: &mut TestAppContext) {
437 let buffer = cx.new(|cx| Buffer::local("hello!", cx));
438 let _diff = cx.new(|cx| Diff::new(buffer.clone(), cx));
439 buffer.update(cx, |buffer, cx| {
440 buffer.set_text("HELLO!", cx);
441 });
442 cx.run_until_parked();
443 }
444}