buffer_diff.rs

   1use futures::channel::oneshot;
   2use git2::{DiffLineType as GitDiffLineType, DiffOptions as GitOptions, Patch as GitPatch};
   3use gpui::{App, AppContext as _, AsyncApp, Context, Entity, EventEmitter, Task, TaskLabel};
   4use language::{
   5    BufferRow, DiffOptions, File, Language, LanguageName, LanguageRegistry,
   6    language_settings::language_settings, word_diff_ranges,
   7};
   8use rope::Rope;
   9use std::{
  10    cmp::Ordering,
  11    future::Future,
  12    iter,
  13    ops::Range,
  14    sync::{Arc, LazyLock},
  15};
  16use sum_tree::SumTree;
  17use text::{Anchor, Bias, BufferId, OffsetRangeExt, Point, ToOffset as _, ToPoint as _};
  18use util::ResultExt;
  19
  20pub static CALCULATE_DIFF_TASK: LazyLock<TaskLabel> = LazyLock::new(TaskLabel::new);
  21pub const MAX_WORD_DIFF_LINE_COUNT: usize = 5;
  22
  23pub struct BufferDiff {
  24    pub buffer_id: BufferId,
  25    inner: BufferDiffInner<Entity<language::Buffer>>,
  26    // diff of the index vs head
  27    secondary_diff: Option<Entity<BufferDiff>>,
  28}
  29
  30#[derive(Clone)]
  31pub struct BufferDiffSnapshot {
  32    inner: BufferDiffInner,
  33    secondary_diff: Option<Box<BufferDiffSnapshot>>,
  34}
  35
  36impl std::fmt::Debug for BufferDiffSnapshot {
  37    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
  38        f.debug_struct("BufferDiffSnapshot")
  39            .field("inner", &self.inner)
  40            .field("secondary_diff", &self.secondary_diff)
  41            .finish()
  42    }
  43}
  44
  45// FIXME figure out how to hide this
  46#[derive(Clone)]
  47pub struct BufferDiffInner<BaseText = language::BufferSnapshot> {
  48    hunks: SumTree<InternalDiffHunk>,
  49    pending_hunks: SumTree<PendingHunk>,
  50    base_text: BaseText,
  51    base_text_exists: bool,
  52}
  53
  54#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
  55pub struct DiffHunkStatus {
  56    pub kind: DiffHunkStatusKind,
  57    pub secondary: DiffHunkSecondaryStatus,
  58}
  59
  60#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
  61pub enum DiffHunkStatusKind {
  62    Added,
  63    Modified,
  64    Deleted,
  65}
  66
  67#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
  68/// Diff of Working Copy vs Index
  69/// aka 'is this hunk staged or not'
  70pub enum DiffHunkSecondaryStatus {
  71    /// Unstaged
  72    HasSecondaryHunk,
  73    /// Partially staged
  74    OverlapsWithSecondaryHunk,
  75    /// Staged
  76    NoSecondaryHunk,
  77    /// We are unstaging
  78    SecondaryHunkAdditionPending,
  79    /// We are stagind
  80    SecondaryHunkRemovalPending,
  81}
  82
  83/// A diff hunk resolved to rows in the buffer.
  84#[derive(Debug, Clone, PartialEq, Eq)]
  85pub struct DiffHunk {
  86    /// The buffer range as points.
  87    pub range: Range<Point>,
  88    /// The range in the buffer to which this hunk corresponds.
  89    pub buffer_range: Range<Anchor>,
  90    /// The range in the buffer's diff base text to which this hunk corresponds.
  91    pub diff_base_byte_range: Range<usize>,
  92    pub secondary_status: DiffHunkSecondaryStatus,
  93    // Anchors representing the word diff locations in the active buffer
  94    pub buffer_word_diffs: Vec<Range<Anchor>>,
  95    // Offsets relative to the start of the deleted diff that represent word diff locations
  96    pub base_word_diffs: Vec<Range<usize>>,
  97}
  98
  99/// We store [`InternalDiffHunk`]s internally so we don't need to store the additional row range.
 100#[derive(Debug, Clone, PartialEq, Eq)]
 101struct InternalDiffHunk {
 102    buffer_range: Range<Anchor>,
 103    diff_base_byte_range: Range<usize>,
 104    base_word_diffs: Vec<Range<usize>>,
 105    buffer_word_diffs: Vec<Range<Anchor>>,
 106}
 107
 108#[derive(Debug, Clone, PartialEq, Eq)]
 109struct PendingHunk {
 110    buffer_range: Range<Anchor>,
 111    diff_base_byte_range: Range<usize>,
 112    buffer_version: clock::Global,
 113    new_status: DiffHunkSecondaryStatus,
 114}
 115
 116#[derive(Debug, Clone)]
 117pub struct DiffHunkSummary {
 118    buffer_range: Range<Anchor>,
 119    diff_base_byte_range: Range<usize>,
 120}
 121
 122impl sum_tree::Item for InternalDiffHunk {
 123    type Summary = DiffHunkSummary;
 124
 125    fn summary(&self, _cx: &text::BufferSnapshot) -> Self::Summary {
 126        DiffHunkSummary {
 127            buffer_range: self.buffer_range.clone(),
 128            diff_base_byte_range: self.diff_base_byte_range.clone(),
 129        }
 130    }
 131}
 132
 133impl sum_tree::Item for PendingHunk {
 134    type Summary = DiffHunkSummary;
 135
 136    fn summary(&self, _cx: &text::BufferSnapshot) -> Self::Summary {
 137        DiffHunkSummary {
 138            buffer_range: self.buffer_range.clone(),
 139            diff_base_byte_range: self.diff_base_byte_range.clone(),
 140        }
 141    }
 142}
 143
 144impl sum_tree::Summary for DiffHunkSummary {
 145    type Context<'a> = &'a text::BufferSnapshot;
 146
 147    fn zero(_cx: Self::Context<'_>) -> Self {
 148        DiffHunkSummary {
 149            buffer_range: Anchor::MIN..Anchor::MIN,
 150            diff_base_byte_range: 0..0,
 151        }
 152    }
 153
 154    fn add_summary(&mut self, other: &Self, buffer: Self::Context<'_>) {
 155        self.buffer_range.start = *self
 156            .buffer_range
 157            .start
 158            .min(&other.buffer_range.start, buffer);
 159        self.buffer_range.end = *self.buffer_range.end.max(&other.buffer_range.end, buffer);
 160
 161        self.diff_base_byte_range.start = self
 162            .diff_base_byte_range
 163            .start
 164            .min(other.diff_base_byte_range.start);
 165        self.diff_base_byte_range.end = self
 166            .diff_base_byte_range
 167            .end
 168            .max(other.diff_base_byte_range.end);
 169    }
 170}
 171
 172impl sum_tree::SeekTarget<'_, DiffHunkSummary, DiffHunkSummary> for Anchor {
 173    fn cmp(&self, cursor_location: &DiffHunkSummary, buffer: &text::BufferSnapshot) -> Ordering {
 174        if self
 175            .cmp(&cursor_location.buffer_range.start, buffer)
 176            .is_lt()
 177        {
 178            Ordering::Less
 179        } else if self.cmp(&cursor_location.buffer_range.end, buffer).is_gt() {
 180            Ordering::Greater
 181        } else {
 182            Ordering::Equal
 183        }
 184    }
 185}
 186
 187impl std::fmt::Debug for BufferDiffInner {
 188    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 189        f.debug_struct("BufferDiffSnapshot")
 190            .field("hunks", &self.hunks)
 191            .field("remote_id", &self.base_text.remote_id())
 192            .finish()
 193    }
 194}
 195
 196impl BufferDiffSnapshot {
 197    pub fn buffer_diff_id(&self) -> BufferId {
 198        self.inner.base_text.remote_id()
 199    }
 200
 201    #[cfg(test)]
 202    fn new_sync(
 203        buffer: text::BufferSnapshot,
 204        diff_base: String,
 205        cx: &mut gpui::TestAppContext,
 206    ) -> BufferDiffSnapshot {
 207        let buffer_diff = cx.new(|cx| BufferDiff::new_with_base_text(&diff_base, &buffer, cx));
 208        buffer_diff.update(cx, |buffer_diff, cx| buffer_diff.snapshot(cx))
 209    }
 210
 211    pub fn is_empty(&self) -> bool {
 212        self.inner.hunks.is_empty()
 213    }
 214
 215    pub fn secondary_diff(&self) -> Option<&BufferDiffSnapshot> {
 216        self.secondary_diff.as_deref()
 217    }
 218
 219    pub fn hunks_intersecting_range<'a>(
 220        &'a self,
 221        range: Range<Anchor>,
 222        buffer: &'a text::BufferSnapshot,
 223    ) -> impl 'a + Iterator<Item = DiffHunk> {
 224        let unstaged_counterpart = self.secondary_diff.as_ref().map(|diff| &diff.inner);
 225        self.inner
 226            .hunks_intersecting_range(range, buffer, unstaged_counterpart)
 227    }
 228
 229    pub fn hunks_intersecting_range_rev<'a>(
 230        &'a self,
 231        range: Range<Anchor>,
 232        buffer: &'a text::BufferSnapshot,
 233    ) -> impl 'a + Iterator<Item = DiffHunk> {
 234        self.inner.hunks_intersecting_range_rev(range, buffer)
 235    }
 236
 237    pub fn hunks_intersecting_base_text_range<'a>(
 238        &'a self,
 239        range: Range<usize>,
 240        main_buffer: &'a text::BufferSnapshot,
 241    ) -> impl 'a + Iterator<Item = DiffHunk> {
 242        let unstaged_counterpart = self.secondary_diff.as_ref().map(|diff| &diff.inner);
 243        let filter = move |summary: &DiffHunkSummary| {
 244            let before_start = summary.diff_base_byte_range.end < range.start;
 245            let after_end = summary.diff_base_byte_range.start > range.end;
 246            !before_start && !after_end
 247        };
 248        self.inner
 249            .hunks_intersecting_range_impl(filter, main_buffer, unstaged_counterpart)
 250    }
 251
 252    pub fn hunks<'a>(
 253        &'a self,
 254        buffer_snapshot: &'a text::BufferSnapshot,
 255    ) -> impl 'a + Iterator<Item = DiffHunk> {
 256        self.hunks_intersecting_range(
 257            Anchor::min_max_range_for_buffer(buffer_snapshot.remote_id()),
 258            buffer_snapshot,
 259        )
 260    }
 261
 262    pub fn hunks_in_row_range<'a>(
 263        &'a self,
 264        range: Range<u32>,
 265        buffer: &'a text::BufferSnapshot,
 266    ) -> impl 'a + Iterator<Item = DiffHunk> {
 267        let start = buffer.anchor_before(Point::new(range.start, 0));
 268        let end = buffer.anchor_after(Point::new(range.end, 0));
 269        self.hunks_intersecting_range(start..end, buffer)
 270    }
 271
 272    pub fn range_to_hunk_range(
 273        &self,
 274        range: Range<Anchor>,
 275        buffer: &text::BufferSnapshot,
 276    ) -> (Option<Range<Anchor>>, Option<Range<usize>>) {
 277        let first_hunk = self.hunks_intersecting_range(range.clone(), buffer).next();
 278        let last_hunk = self.hunks_intersecting_range_rev(range, buffer).next();
 279        let range = first_hunk
 280            .as_ref()
 281            .zip(last_hunk.as_ref())
 282            .map(|(first, last)| first.buffer_range.start..last.buffer_range.end);
 283        let base_text_range = first_hunk
 284            .zip(last_hunk)
 285            .map(|(first, last)| first.diff_base_byte_range.start..last.diff_base_byte_range.end);
 286        (range, base_text_range)
 287    }
 288
 289    pub fn base_text(&self) -> &language::BufferSnapshot {
 290        &self.inner.base_text
 291    }
 292
 293    pub fn base_texts_eq(&self, other: &Self) -> bool {
 294        if self.inner.base_text_exists != other.inner.base_text_exists {
 295            return false;
 296        }
 297        let left = &self.inner.base_text;
 298        let right = &other.inner.base_text;
 299        let (old_id, old_empty) = (left.remote_id(), left.is_empty());
 300        let (new_id, new_empty) = (right.remote_id(), right.is_empty());
 301        new_id == old_id || (new_empty && old_empty)
 302    }
 303
 304    pub fn row_to_base_text_row(&self, row: BufferRow, buffer: &text::BufferSnapshot) -> u32 {
 305        // TODO(split-diff) expose a parameter to reuse a cursor to avoid repeatedly seeking from the start
 306
 307        // Find the last hunk that starts before this position.
 308        let mut cursor = self.inner.hunks.cursor::<DiffHunkSummary>(buffer);
 309        let position = buffer.anchor_before(Point::new(row, 0));
 310        cursor.seek(&position, Bias::Left);
 311        if cursor
 312            .item()
 313            .is_none_or(|hunk| hunk.buffer_range.start.cmp(&position, buffer).is_gt())
 314        {
 315            cursor.prev();
 316        }
 317
 318        let unclipped_point = if let Some(hunk) = cursor.item()
 319            && hunk.buffer_range.start.cmp(&position, buffer).is_le()
 320        {
 321            let mut unclipped_point = cursor
 322                .end()
 323                .diff_base_byte_range
 324                .end
 325                .to_point(self.base_text());
 326            if position.cmp(&cursor.end().buffer_range.end, buffer).is_ge() {
 327                unclipped_point +=
 328                    Point::new(row, 0) - cursor.end().buffer_range.end.to_point(buffer);
 329            }
 330            // Move the cursor so that at the next step we can clip with the start of the next hunk.
 331            cursor.next();
 332            unclipped_point
 333        } else {
 334            // Position is before the added region for the first hunk.
 335            debug_assert!(self.inner.hunks.first().is_none_or(|first_hunk| {
 336                position.cmp(&first_hunk.buffer_range.start, buffer).is_le()
 337            }));
 338            Point::new(row, 0)
 339        };
 340
 341        let max_point = if let Some(next_hunk) = cursor.item() {
 342            next_hunk
 343                .diff_base_byte_range
 344                .start
 345                .to_point(self.base_text())
 346        } else {
 347            self.base_text().max_point()
 348        };
 349        unclipped_point.min(max_point).row
 350    }
 351}
 352
 353impl BufferDiffInner<Entity<language::Buffer>> {
 354    /// Returns the new index text and new pending hunks.
 355    fn stage_or_unstage_hunks_impl(
 356        &mut self,
 357        unstaged_diff: &Self,
 358        stage: bool,
 359        hunks: &[DiffHunk],
 360        buffer: &text::BufferSnapshot,
 361        file_exists: bool,
 362        cx: &mut Context<BufferDiff>,
 363    ) -> Option<Rope> {
 364        let head_text = self
 365            .base_text_exists
 366            .then(|| self.base_text.read(cx).as_rope().clone());
 367        let index_text = unstaged_diff
 368            .base_text_exists
 369            .then(|| unstaged_diff.base_text.read(cx).as_rope().clone());
 370
 371        // If the file doesn't exist in either HEAD or the index, then the
 372        // entire file must be either created or deleted in the index.
 373        let (index_text, head_text) = match (index_text, head_text) {
 374            (Some(index_text), Some(head_text)) if file_exists || !stage => (index_text, head_text),
 375            (index_text, head_text) => {
 376                let (new_index_text, new_status) = if stage {
 377                    log::debug!("stage all");
 378                    (
 379                        file_exists.then(|| buffer.as_rope().clone()),
 380                        DiffHunkSecondaryStatus::SecondaryHunkRemovalPending,
 381                    )
 382                } else {
 383                    log::debug!("unstage all");
 384                    (
 385                        head_text,
 386                        DiffHunkSecondaryStatus::SecondaryHunkAdditionPending,
 387                    )
 388                };
 389
 390                let hunk = PendingHunk {
 391                    buffer_range: Anchor::min_max_range_for_buffer(buffer.remote_id()),
 392                    diff_base_byte_range: 0..index_text.map_or(0, |rope| rope.len()),
 393                    buffer_version: buffer.version().clone(),
 394                    new_status,
 395                };
 396                self.pending_hunks = SumTree::from_item(hunk, buffer);
 397                return new_index_text;
 398            }
 399        };
 400
 401        let mut pending_hunks = SumTree::new(buffer);
 402        let mut old_pending_hunks = self.pending_hunks.cursor::<DiffHunkSummary>(buffer);
 403
 404        // first, merge new hunks into pending_hunks
 405        for DiffHunk {
 406            buffer_range,
 407            diff_base_byte_range,
 408            secondary_status,
 409            ..
 410        } in hunks.iter().cloned()
 411        {
 412            let preceding_pending_hunks = old_pending_hunks.slice(&buffer_range.start, Bias::Left);
 413            pending_hunks.append(preceding_pending_hunks, buffer);
 414
 415            // Skip all overlapping or adjacent old pending hunks
 416            while old_pending_hunks.item().is_some_and(|old_hunk| {
 417                old_hunk
 418                    .buffer_range
 419                    .start
 420                    .cmp(&buffer_range.end, buffer)
 421                    .is_le()
 422            }) {
 423                old_pending_hunks.next();
 424            }
 425
 426            if (stage && secondary_status == DiffHunkSecondaryStatus::NoSecondaryHunk)
 427                || (!stage && secondary_status == DiffHunkSecondaryStatus::HasSecondaryHunk)
 428            {
 429                continue;
 430            }
 431
 432            pending_hunks.push(
 433                PendingHunk {
 434                    buffer_range,
 435                    diff_base_byte_range,
 436                    buffer_version: buffer.version().clone(),
 437                    new_status: if stage {
 438                        DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
 439                    } else {
 440                        DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
 441                    },
 442                },
 443                buffer,
 444            );
 445        }
 446        // append the remainder
 447        pending_hunks.append(old_pending_hunks.suffix(), buffer);
 448
 449        let mut unstaged_hunk_cursor = unstaged_diff.hunks.cursor::<DiffHunkSummary>(buffer);
 450        unstaged_hunk_cursor.next();
 451
 452        // then, iterate over all pending hunks (both new ones and the existing ones) and compute the edits
 453        let mut prev_unstaged_hunk_buffer_end = 0;
 454        let mut prev_unstaged_hunk_base_text_end = 0;
 455        let mut edits = Vec::<(Range<usize>, String)>::new();
 456        let mut pending_hunks_iter = pending_hunks.iter().cloned().peekable();
 457        while let Some(PendingHunk {
 458            buffer_range,
 459            diff_base_byte_range,
 460            new_status,
 461            ..
 462        }) = pending_hunks_iter.next()
 463        {
 464            // Advance unstaged_hunk_cursor to skip unstaged hunks before current hunk
 465            let skipped_unstaged = unstaged_hunk_cursor.slice(&buffer_range.start, Bias::Left);
 466
 467            if let Some(unstaged_hunk) = skipped_unstaged.last() {
 468                prev_unstaged_hunk_base_text_end = unstaged_hunk.diff_base_byte_range.end;
 469                prev_unstaged_hunk_buffer_end = unstaged_hunk.buffer_range.end.to_offset(buffer);
 470            }
 471
 472            // Find where this hunk is in the index if it doesn't overlap
 473            let mut buffer_offset_range = buffer_range.to_offset(buffer);
 474            let start_overshoot = buffer_offset_range.start - prev_unstaged_hunk_buffer_end;
 475            let mut index_start = prev_unstaged_hunk_base_text_end + start_overshoot;
 476
 477            loop {
 478                // Merge this hunk with any overlapping unstaged hunks.
 479                if let Some(unstaged_hunk) = unstaged_hunk_cursor.item() {
 480                    let unstaged_hunk_offset_range = unstaged_hunk.buffer_range.to_offset(buffer);
 481                    if unstaged_hunk_offset_range.start <= buffer_offset_range.end {
 482                        prev_unstaged_hunk_base_text_end = unstaged_hunk.diff_base_byte_range.end;
 483                        prev_unstaged_hunk_buffer_end = unstaged_hunk_offset_range.end;
 484
 485                        index_start = index_start.min(unstaged_hunk.diff_base_byte_range.start);
 486                        buffer_offset_range.start = buffer_offset_range
 487                            .start
 488                            .min(unstaged_hunk_offset_range.start);
 489                        buffer_offset_range.end =
 490                            buffer_offset_range.end.max(unstaged_hunk_offset_range.end);
 491
 492                        unstaged_hunk_cursor.next();
 493                        continue;
 494                    }
 495                }
 496
 497                // If any unstaged hunks were merged, then subsequent pending hunks may
 498                // now overlap this hunk. Merge them.
 499                if let Some(next_pending_hunk) = pending_hunks_iter.peek() {
 500                    let next_pending_hunk_offset_range =
 501                        next_pending_hunk.buffer_range.to_offset(buffer);
 502                    if next_pending_hunk_offset_range.start <= buffer_offset_range.end {
 503                        buffer_offset_range.end = next_pending_hunk_offset_range.end;
 504                        pending_hunks_iter.next();
 505                        continue;
 506                    }
 507                }
 508
 509                break;
 510            }
 511
 512            let end_overshoot = buffer_offset_range
 513                .end
 514                .saturating_sub(prev_unstaged_hunk_buffer_end);
 515            let index_end = prev_unstaged_hunk_base_text_end + end_overshoot;
 516            let index_byte_range = index_start..index_end;
 517
 518            let replacement_text = match new_status {
 519                DiffHunkSecondaryStatus::SecondaryHunkRemovalPending => {
 520                    log::debug!("staging hunk {:?}", buffer_offset_range);
 521                    buffer
 522                        .text_for_range(buffer_offset_range)
 523                        .collect::<String>()
 524                }
 525                DiffHunkSecondaryStatus::SecondaryHunkAdditionPending => {
 526                    log::debug!("unstaging hunk {:?}", buffer_offset_range);
 527                    head_text
 528                        .chunks_in_range(diff_base_byte_range.clone())
 529                        .collect::<String>()
 530                }
 531                _ => {
 532                    debug_assert!(false);
 533                    continue;
 534                }
 535            };
 536
 537            edits.push((index_byte_range, replacement_text));
 538        }
 539        drop(pending_hunks_iter);
 540        drop(old_pending_hunks);
 541        self.pending_hunks = pending_hunks;
 542
 543        #[cfg(debug_assertions)] // invariants: non-overlapping and sorted
 544        {
 545            for window in edits.windows(2) {
 546                let (range_a, range_b) = (&window[0].0, &window[1].0);
 547                debug_assert!(range_a.end < range_b.start);
 548            }
 549        }
 550
 551        let mut new_index_text = Rope::new();
 552        let mut index_cursor = index_text.cursor(0);
 553
 554        for (old_range, replacement_text) in edits {
 555            new_index_text.append(index_cursor.slice(old_range.start));
 556            index_cursor.seek_forward(old_range.end);
 557            new_index_text.push(&replacement_text);
 558        }
 559        new_index_text.append(index_cursor.suffix());
 560        Some(new_index_text)
 561    }
 562}
 563
 564impl BufferDiffInner {
 565    fn hunks_intersecting_range<'a>(
 566        &'a self,
 567        range: Range<Anchor>,
 568        buffer: &'a text::BufferSnapshot,
 569        secondary: Option<&'a Self>,
 570    ) -> impl 'a + Iterator<Item = DiffHunk> {
 571        let range = range.to_offset(buffer);
 572        let filter = move |summary: &DiffHunkSummary| {
 573            let summary_range = summary.buffer_range.to_offset(buffer);
 574            let before_start = summary_range.end < range.start;
 575            let after_end = summary_range.start > range.end;
 576            !before_start && !after_end
 577        };
 578        self.hunks_intersecting_range_impl(filter, buffer, secondary)
 579    }
 580
 581    fn hunks_intersecting_range_impl<'a>(
 582        &'a self,
 583        filter: impl 'a + Fn(&DiffHunkSummary) -> bool,
 584        buffer: &'a text::BufferSnapshot,
 585        secondary: Option<&'a Self>,
 586    ) -> impl 'a + Iterator<Item = DiffHunk> {
 587        let mut cursor = self.hunks.filter::<_, DiffHunkSummary>(buffer, filter);
 588
 589        let anchor_iter = iter::from_fn(move || {
 590            cursor.next();
 591            cursor.item()
 592        })
 593        .flat_map(move |hunk| {
 594            [
 595                (
 596                    &hunk.buffer_range.start,
 597                    (
 598                        hunk.buffer_range.start,
 599                        hunk.diff_base_byte_range.start,
 600                        hunk,
 601                    ),
 602                ),
 603                (
 604                    &hunk.buffer_range.end,
 605                    (hunk.buffer_range.end, hunk.diff_base_byte_range.end, hunk),
 606                ),
 607            ]
 608        });
 609
 610        let mut pending_hunks_cursor = self.pending_hunks.cursor::<DiffHunkSummary>(buffer);
 611        pending_hunks_cursor.next();
 612
 613        let mut secondary_cursor = None;
 614        if let Some(secondary) = secondary.as_ref() {
 615            let mut cursor = secondary.hunks.cursor::<DiffHunkSummary>(buffer);
 616            cursor.next();
 617            secondary_cursor = Some(cursor);
 618        }
 619
 620        let max_point = buffer.max_point();
 621        let mut summaries = buffer.summaries_for_anchors_with_payload::<Point, _, _>(anchor_iter);
 622        iter::from_fn(move || {
 623            loop {
 624                let (start_point, (start_anchor, start_base, hunk)) = summaries.next()?;
 625                let (mut end_point, (mut end_anchor, end_base, _)) = summaries.next()?;
 626
 627                let base_word_diffs = hunk.base_word_diffs.clone();
 628                let buffer_word_diffs = hunk.buffer_word_diffs.clone();
 629
 630                if !start_anchor.is_valid(buffer) {
 631                    continue;
 632                }
 633
 634                if end_point.column > 0 && end_point < max_point {
 635                    end_point.row += 1;
 636                    end_point.column = 0;
 637                    end_anchor = buffer.anchor_before(end_point);
 638                }
 639
 640                let mut secondary_status = DiffHunkSecondaryStatus::NoSecondaryHunk;
 641
 642                let mut has_pending = false;
 643                if start_anchor
 644                    .cmp(&pending_hunks_cursor.start().buffer_range.start, buffer)
 645                    .is_gt()
 646                {
 647                    pending_hunks_cursor.seek_forward(&start_anchor, Bias::Left);
 648                }
 649
 650                if let Some(pending_hunk) = pending_hunks_cursor.item() {
 651                    let mut pending_range = pending_hunk.buffer_range.to_point(buffer);
 652                    if pending_range.end.column > 0 {
 653                        pending_range.end.row += 1;
 654                        pending_range.end.column = 0;
 655                    }
 656
 657                    if pending_range == (start_point..end_point)
 658                        && !buffer.has_edits_since_in_range(
 659                            &pending_hunk.buffer_version,
 660                            start_anchor..end_anchor,
 661                        )
 662                    {
 663                        has_pending = true;
 664                        secondary_status = pending_hunk.new_status;
 665                    }
 666                }
 667
 668                if let (Some(secondary_cursor), false) = (secondary_cursor.as_mut(), has_pending) {
 669                    if start_anchor
 670                        .cmp(&secondary_cursor.start().buffer_range.start, buffer)
 671                        .is_gt()
 672                    {
 673                        secondary_cursor.seek_forward(&start_anchor, Bias::Left);
 674                    }
 675
 676                    if let Some(secondary_hunk) = secondary_cursor.item() {
 677                        let mut secondary_range = secondary_hunk.buffer_range.to_point(buffer);
 678                        if secondary_range.end.column > 0 {
 679                            secondary_range.end.row += 1;
 680                            secondary_range.end.column = 0;
 681                        }
 682                        if secondary_range.is_empty()
 683                            && secondary_hunk.diff_base_byte_range.is_empty()
 684                        {
 685                            // ignore
 686                        } else if secondary_range == (start_point..end_point) {
 687                            secondary_status = DiffHunkSecondaryStatus::HasSecondaryHunk;
 688                        } else if secondary_range.start <= end_point {
 689                            secondary_status = DiffHunkSecondaryStatus::OverlapsWithSecondaryHunk;
 690                        }
 691                    }
 692                }
 693
 694                return Some(DiffHunk {
 695                    range: start_point..end_point,
 696                    diff_base_byte_range: start_base..end_base,
 697                    buffer_range: start_anchor..end_anchor,
 698                    base_word_diffs,
 699                    buffer_word_diffs,
 700                    secondary_status,
 701                });
 702            }
 703        })
 704    }
 705
 706    fn hunks_intersecting_range_rev<'a>(
 707        &'a self,
 708        range: Range<Anchor>,
 709        buffer: &'a text::BufferSnapshot,
 710    ) -> impl 'a + Iterator<Item = DiffHunk> {
 711        let mut cursor = self
 712            .hunks
 713            .filter::<_, DiffHunkSummary>(buffer, move |summary| {
 714                let before_start = summary.buffer_range.end.cmp(&range.start, buffer).is_lt();
 715                let after_end = summary.buffer_range.start.cmp(&range.end, buffer).is_gt();
 716                !before_start && !after_end
 717            });
 718
 719        iter::from_fn(move || {
 720            cursor.prev();
 721
 722            let hunk = cursor.item()?;
 723            let range = hunk.buffer_range.to_point(buffer);
 724
 725            Some(DiffHunk {
 726                range,
 727                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
 728                buffer_range: hunk.buffer_range.clone(),
 729                // The secondary status is not used by callers of this method.
 730                secondary_status: DiffHunkSecondaryStatus::NoSecondaryHunk,
 731                base_word_diffs: hunk.base_word_diffs.clone(),
 732                buffer_word_diffs: hunk.buffer_word_diffs.clone(),
 733            })
 734        })
 735    }
 736}
 737
 738fn build_diff_options(
 739    file: Option<&Arc<dyn File>>,
 740    language: Option<LanguageName>,
 741    language_scope: Option<language::LanguageScope>,
 742    cx: &App,
 743) -> Option<DiffOptions> {
 744    #[cfg(any(test, feature = "test-support"))]
 745    {
 746        if !cx.has_global::<settings::SettingsStore>() {
 747            return Some(DiffOptions {
 748                language_scope,
 749                max_word_diff_line_count: MAX_WORD_DIFF_LINE_COUNT,
 750                ..Default::default()
 751            });
 752        }
 753    }
 754
 755    language_settings(language, file, cx)
 756        .word_diff_enabled
 757        .then_some(DiffOptions {
 758            language_scope,
 759            max_word_diff_line_count: MAX_WORD_DIFF_LINE_COUNT,
 760            ..Default::default()
 761        })
 762}
 763
 764fn compute_hunks(
 765    diff_base: Option<(Arc<str>, Rope)>,
 766    buffer: text::BufferSnapshot,
 767    diff_options: Option<DiffOptions>,
 768) -> SumTree<InternalDiffHunk> {
 769    let mut tree = SumTree::new(&buffer);
 770
 771    if let Some((diff_base, diff_base_rope)) = diff_base {
 772        let buffer_text = buffer.as_rope().to_string();
 773
 774        let mut options = GitOptions::default();
 775        options.context_lines(0);
 776        let patch = GitPatch::from_buffers(
 777            diff_base.as_bytes(),
 778            None,
 779            buffer_text.as_bytes(),
 780            None,
 781            Some(&mut options),
 782        )
 783        .log_err();
 784
 785        // A common case in Zed is that the empty buffer is represented as just a newline,
 786        // but if we just compute a naive diff you get a "preserved" line in the middle,
 787        // which is a bit odd.
 788        if buffer_text == "\n" && diff_base.ends_with("\n") && diff_base.len() > 1 {
 789            tree.push(
 790                InternalDiffHunk {
 791                    buffer_range: buffer.anchor_before(0)..buffer.anchor_before(0),
 792                    diff_base_byte_range: 0..diff_base.len() - 1,
 793                    base_word_diffs: Vec::default(),
 794                    buffer_word_diffs: Vec::default(),
 795                },
 796                &buffer,
 797            );
 798            return tree;
 799        }
 800
 801        if let Some(patch) = patch {
 802            let mut divergence = 0;
 803            for hunk_index in 0..patch.num_hunks() {
 804                let hunk = process_patch_hunk(
 805                    &patch,
 806                    hunk_index,
 807                    &diff_base_rope,
 808                    &buffer,
 809                    &mut divergence,
 810                    diff_options.as_ref(),
 811                );
 812                tree.push(hunk, &buffer);
 813            }
 814        }
 815    } else {
 816        tree.push(
 817            InternalDiffHunk {
 818                buffer_range: Anchor::min_max_range_for_buffer(buffer.remote_id()),
 819                diff_base_byte_range: 0..0,
 820                base_word_diffs: Vec::default(),
 821                buffer_word_diffs: Vec::default(),
 822            },
 823            &buffer,
 824        );
 825    }
 826
 827    tree
 828}
 829
 830fn compare_hunks(
 831    new_hunks: &SumTree<InternalDiffHunk>,
 832    old_hunks: &SumTree<InternalDiffHunk>,
 833    new_snapshot: &text::BufferSnapshot,
 834) -> (Option<Range<Anchor>>, Option<Range<usize>>) {
 835    let mut new_cursor = new_hunks.cursor::<()>(new_snapshot);
 836    let mut old_cursor = old_hunks.cursor::<()>(new_snapshot);
 837    old_cursor.next();
 838    new_cursor.next();
 839    let mut start = None;
 840    let mut end = None;
 841    let mut base_text_start = None;
 842    let mut base_text_end = None;
 843
 844    loop {
 845        match (new_cursor.item(), old_cursor.item()) {
 846            (Some(new_hunk), Some(old_hunk)) => {
 847                match new_hunk
 848                    .buffer_range
 849                    .start
 850                    .cmp(&old_hunk.buffer_range.start, new_snapshot)
 851                {
 852                    Ordering::Less => {
 853                        start.get_or_insert(new_hunk.buffer_range.start);
 854                        base_text_start.get_or_insert(new_hunk.diff_base_byte_range.start);
 855                        end.replace(new_hunk.buffer_range.end);
 856                        base_text_end.get_or_insert(new_hunk.diff_base_byte_range.end);
 857                        new_cursor.next();
 858                    }
 859                    Ordering::Equal => {
 860                        if new_hunk != old_hunk {
 861                            start.get_or_insert(new_hunk.buffer_range.start);
 862                            base_text_start.get_or_insert(new_hunk.diff_base_byte_range.start);
 863                            if old_hunk
 864                                .buffer_range
 865                                .end
 866                                .cmp(&new_hunk.buffer_range.end, new_snapshot)
 867                                .is_ge()
 868                            {
 869                                end.replace(old_hunk.buffer_range.end);
 870                                base_text_end.replace(old_hunk.diff_base_byte_range.end);
 871                            } else {
 872                                end.replace(new_hunk.buffer_range.end);
 873                                base_text_end.replace(new_hunk.diff_base_byte_range.end);
 874                            }
 875                        }
 876
 877                        new_cursor.next();
 878                        old_cursor.next();
 879                    }
 880                    Ordering::Greater => {
 881                        start.get_or_insert(old_hunk.buffer_range.start);
 882                        base_text_start.get_or_insert(old_hunk.diff_base_byte_range.start);
 883                        end.replace(old_hunk.buffer_range.end);
 884                        base_text_end.replace(old_hunk.diff_base_byte_range.end);
 885                        old_cursor.next();
 886                    }
 887                }
 888            }
 889            (Some(new_hunk), None) => {
 890                start.get_or_insert(new_hunk.buffer_range.start);
 891                base_text_start.get_or_insert(new_hunk.diff_base_byte_range.start);
 892                end.replace(new_hunk.buffer_range.end);
 893                base_text_end.replace(new_hunk.diff_base_byte_range.end);
 894                new_cursor.next();
 895            }
 896            (None, Some(old_hunk)) => {
 897                start.get_or_insert(old_hunk.buffer_range.start);
 898                base_text_start.get_or_insert(old_hunk.diff_base_byte_range.start);
 899                end.replace(old_hunk.buffer_range.end);
 900                base_text_end.replace(old_hunk.diff_base_byte_range.end);
 901                old_cursor.next();
 902            }
 903            (None, None) => break,
 904        }
 905    }
 906
 907    (
 908        start.zip(end).map(|(start, end)| start..end),
 909        base_text_start
 910            .zip(base_text_end)
 911            .map(|(start, end)| start..end),
 912    )
 913}
 914
 915fn process_patch_hunk(
 916    patch: &GitPatch<'_>,
 917    hunk_index: usize,
 918    diff_base: &Rope,
 919    buffer: &text::BufferSnapshot,
 920    buffer_row_divergence: &mut i64,
 921    diff_options: Option<&DiffOptions>,
 922) -> InternalDiffHunk {
 923    let line_item_count = patch.num_lines_in_hunk(hunk_index).unwrap();
 924    assert!(line_item_count > 0);
 925
 926    let mut first_deletion_buffer_row: Option<u32> = None;
 927    let mut buffer_row_range: Option<Range<u32>> = None;
 928    let mut diff_base_byte_range: Option<Range<usize>> = None;
 929    let mut first_addition_old_row: Option<u32> = None;
 930
 931    for line_index in 0..line_item_count {
 932        let line = patch.line_in_hunk(hunk_index, line_index).unwrap();
 933        let kind = line.origin_value();
 934        let content_offset = line.content_offset() as isize;
 935        let content_len = line.content().len() as isize;
 936        match kind {
 937            GitDiffLineType::Addition => {
 938                if first_addition_old_row.is_none() {
 939                    first_addition_old_row = Some(
 940                        (line.new_lineno().unwrap() as i64 - *buffer_row_divergence - 1) as u32,
 941                    );
 942                }
 943                *buffer_row_divergence += 1;
 944                let row = line.new_lineno().unwrap().saturating_sub(1);
 945
 946                match &mut buffer_row_range {
 947                    Some(Range { end, .. }) => *end = row + 1,
 948                    None => buffer_row_range = Some(row..row + 1),
 949                }
 950            }
 951            GitDiffLineType::Deletion => {
 952                let end = content_offset + content_len;
 953
 954                match &mut diff_base_byte_range {
 955                    Some(head_byte_range) => head_byte_range.end = end as usize,
 956                    None => diff_base_byte_range = Some(content_offset as usize..end as usize),
 957                }
 958
 959                if first_deletion_buffer_row.is_none() {
 960                    let old_row = line.old_lineno().unwrap().saturating_sub(1);
 961                    let row = old_row as i64 + *buffer_row_divergence;
 962                    first_deletion_buffer_row = Some(row as u32);
 963                }
 964
 965                *buffer_row_divergence -= 1;
 966            }
 967            _ => {}
 968        }
 969    }
 970
 971    let buffer_row_range = buffer_row_range.unwrap_or_else(|| {
 972        // Pure deletion hunk without addition.
 973        let row = first_deletion_buffer_row.unwrap();
 974        row..row
 975    });
 976    let diff_base_byte_range = diff_base_byte_range.unwrap_or_else(|| {
 977        // Pure addition hunk without deletion.
 978        let row = first_addition_old_row.unwrap();
 979        let offset = diff_base.point_to_offset(Point::new(row, 0));
 980        offset..offset
 981    });
 982
 983    let start = Point::new(buffer_row_range.start, 0);
 984    let end = Point::new(buffer_row_range.end, 0);
 985    let buffer_range = buffer.anchor_before(start)..buffer.anchor_before(end);
 986
 987    let base_line_count = line_item_count.saturating_sub(buffer_row_range.len());
 988
 989    let (base_word_diffs, buffer_word_diffs) = if let Some(diff_options) = diff_options
 990        && !buffer_row_range.is_empty()
 991        && base_line_count == buffer_row_range.len()
 992        && diff_options.max_word_diff_line_count >= base_line_count
 993    {
 994        let base_text: String = diff_base
 995            .chunks_in_range(diff_base_byte_range.clone())
 996            .collect();
 997
 998        let buffer_text: String = buffer.text_for_range(buffer_range.clone()).collect();
 999
1000        let (base_word_diffs, buffer_word_diffs_relative) = word_diff_ranges(
1001            &base_text,
1002            &buffer_text,
1003            DiffOptions {
1004                language_scope: diff_options.language_scope.clone(),
1005                ..*diff_options
1006            },
1007        );
1008
1009        let buffer_start_offset = buffer_range.start.to_offset(buffer);
1010        let buffer_word_diffs = buffer_word_diffs_relative
1011            .into_iter()
1012            .map(|range| {
1013                let start = buffer.anchor_after(buffer_start_offset + range.start);
1014                let end = buffer.anchor_after(buffer_start_offset + range.end);
1015                start..end
1016            })
1017            .collect();
1018
1019        (base_word_diffs, buffer_word_diffs)
1020    } else {
1021        (Vec::default(), Vec::default())
1022    };
1023
1024    InternalDiffHunk {
1025        buffer_range,
1026        diff_base_byte_range,
1027        base_word_diffs,
1028        buffer_word_diffs,
1029    }
1030}
1031
1032impl std::fmt::Debug for BufferDiff {
1033    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1034        f.debug_struct("BufferChangeSet")
1035            .field("buffer_id", &self.buffer_id)
1036            .finish()
1037    }
1038}
1039
1040#[derive(Clone, Debug)]
1041pub enum BufferDiffEvent {
1042    DiffChanged {
1043        changed_range: Option<Range<text::Anchor>>,
1044        base_text_changed_range: Option<Range<usize>>,
1045    },
1046    LanguageChanged,
1047    HunksStagedOrUnstaged(Option<Rope>),
1048}
1049
1050impl EventEmitter<BufferDiffEvent> for BufferDiff {}
1051
1052impl BufferDiff {
1053    pub fn new(buffer: &text::BufferSnapshot, cx: &mut App) -> Self {
1054        BufferDiff {
1055            buffer_id: buffer.remote_id(),
1056            inner: BufferDiffInner {
1057                base_text: cx.new(|cx| language::Buffer::local("", cx)),
1058                hunks: SumTree::new(buffer),
1059                pending_hunks: SumTree::new(buffer),
1060                base_text_exists: false,
1061            },
1062            secondary_diff: None,
1063        }
1064    }
1065
1066    pub fn new_unchanged(buffer: &text::BufferSnapshot, cx: &mut Context<Self>) -> Self {
1067        let base_text = buffer.text();
1068        BufferDiff {
1069            buffer_id: buffer.remote_id(),
1070            inner: BufferDiffInner {
1071                base_text: cx.new(|cx| language::Buffer::local(base_text, cx)),
1072                hunks: SumTree::new(buffer),
1073                pending_hunks: SumTree::new(buffer),
1074                base_text_exists: false,
1075            },
1076            secondary_diff: None,
1077        }
1078    }
1079
1080    #[cfg(any(test, feature = "test-support"))]
1081    pub fn new_with_base_text(
1082        base_text: &str,
1083        buffer: &text::BufferSnapshot,
1084        cx: &mut Context<Self>,
1085    ) -> Self {
1086        let mut this = BufferDiff::new(&buffer, cx);
1087        let executor = cx.background_executor().clone();
1088        let mut base_text = base_text.to_owned();
1089        text::LineEnding::normalize(&mut base_text);
1090        let inner = executor.block(this.update_diff(
1091            buffer.clone(),
1092            Some(Arc::from(base_text)),
1093            true,
1094            None,
1095            cx,
1096        ));
1097        // FIXME
1098        this.set_snapshot(inner, &buffer, true, cx);
1099        this
1100    }
1101
1102    pub fn set_secondary_diff(&mut self, diff: Entity<BufferDiff>) {
1103        self.secondary_diff = Some(diff);
1104    }
1105
1106    pub fn secondary_diff(&self) -> Option<Entity<BufferDiff>> {
1107        self.secondary_diff.clone()
1108    }
1109
1110    pub fn clear_pending_hunks(&mut self, cx: &mut Context<Self>) {
1111        if self.secondary_diff.is_some() {
1112            self.inner.pending_hunks = SumTree::from_summary(DiffHunkSummary {
1113                buffer_range: Anchor::min_min_range_for_buffer(self.buffer_id),
1114                diff_base_byte_range: 0..0,
1115            });
1116            cx.emit(BufferDiffEvent::DiffChanged {
1117                changed_range: Some(Anchor::min_max_range_for_buffer(self.buffer_id)),
1118                base_text_changed_range: Some(0..self.base_text(cx).len()),
1119            });
1120        }
1121    }
1122
1123    pub fn stage_or_unstage_hunks(
1124        &mut self,
1125        stage: bool,
1126        hunks: &[DiffHunk],
1127        buffer: &text::BufferSnapshot,
1128        file_exists: bool,
1129        cx: &mut Context<Self>,
1130    ) -> Option<Rope> {
1131        let new_index_text = self
1132            .secondary_diff
1133            .as_ref()?
1134            .update(cx, |secondary_diff, cx| {
1135                self.inner.stage_or_unstage_hunks_impl(
1136                    &secondary_diff.inner,
1137                    stage,
1138                    hunks,
1139                    buffer,
1140                    file_exists,
1141                    cx,
1142                )
1143            });
1144
1145        cx.emit(BufferDiffEvent::HunksStagedOrUnstaged(
1146            new_index_text.clone(),
1147        ));
1148        if let Some((first, last)) = hunks.first().zip(hunks.last()) {
1149            let changed_range = first.buffer_range.start..last.buffer_range.end;
1150            let base_text_changed_range =
1151                first.diff_base_byte_range.start..last.diff_base_byte_range.end;
1152            cx.emit(BufferDiffEvent::DiffChanged {
1153                changed_range: Some(changed_range),
1154                base_text_changed_range: Some(base_text_changed_range),
1155            });
1156        }
1157        new_index_text
1158    }
1159
1160    pub fn update_diff(
1161        &self,
1162        buffer: text::BufferSnapshot,
1163        base_text: Option<Arc<str>>,
1164        base_text_changed: bool,
1165        language: Option<Arc<Language>>,
1166        cx: &App,
1167    ) -> Task<BufferDiffInner<Arc<str>>> {
1168        let prev_base_text = self.base_text(cx).as_rope().clone();
1169        let diff_options = build_diff_options(
1170            None,
1171            language.as_ref().map(|l| l.name()),
1172            language.as_ref().map(|l| l.default_scope()),
1173            cx,
1174        );
1175
1176        cx.background_executor()
1177            .spawn_labeled(*CALCULATE_DIFF_TASK, async move {
1178                let base_text_rope = if let Some(base_text) = &base_text {
1179                    if base_text_changed {
1180                        Rope::from(base_text.as_ref())
1181                    } else {
1182                        prev_base_text
1183                    }
1184                } else {
1185                    Rope::new()
1186                };
1187                let base_text_exists = base_text.is_some();
1188                let hunks = compute_hunks(
1189                    base_text
1190                        .clone()
1191                        .map(|base_text| (base_text, base_text_rope.clone())),
1192                    buffer.clone(),
1193                    diff_options,
1194                );
1195                let base_text = base_text.unwrap_or_default();
1196                if cfg!(debug_assertions) {
1197                    for hunk in hunks.iter() {
1198                        base_text.get(hunk.diff_base_byte_range.clone()).unwrap();
1199                    }
1200                }
1201                BufferDiffInner {
1202                    base_text,
1203                    hunks,
1204                    base_text_exists,
1205                    pending_hunks: SumTree::new(&buffer),
1206                }
1207            })
1208    }
1209
1210    pub fn language_changed(&mut self, cx: &mut Context<Self>) {
1211        cx.emit(BufferDiffEvent::LanguageChanged);
1212    }
1213
1214    // FIXME name
1215    pub fn set_snapshot(
1216        &mut self,
1217        new_state: BufferDiffInner<Arc<str>>,
1218        buffer: &text::BufferSnapshot,
1219        base_text_changed: bool,
1220        cx: &mut Context<Self>,
1221    ) -> Option<Range<Anchor>> {
1222        self.set_snapshot_with_secondary(new_state, buffer, None, base_text_changed, false, cx)
1223    }
1224
1225    // FIXME name
1226    pub fn set_snapshot_with_secondary(
1227        &mut self,
1228        new_state: BufferDiffInner<Arc<str>>,
1229        buffer: &text::BufferSnapshot,
1230        secondary_diff_change: Option<Range<Anchor>>,
1231        base_text_changed: bool,
1232        clear_pending_hunks: bool,
1233        cx: &mut Context<Self>,
1234    ) -> Option<Range<Anchor>> {
1235        log::debug!("set snapshot with secondary {secondary_diff_change:?}");
1236
1237        let old_snapshot = self.snapshot(cx);
1238        let state = &mut self.inner;
1239        let (mut changed_range, mut base_text_changed_range) =
1240            match (state.base_text_exists, new_state.base_text_exists) {
1241                (false, false) => (None, None),
1242                (true, true) if !base_text_changed => {
1243                    compare_hunks(&new_state.hunks, &old_snapshot.inner.hunks, buffer)
1244                }
1245                _ => (
1246                    Some(text::Anchor::min_max_range_for_buffer(self.buffer_id)),
1247                    Some(0..new_state.base_text.len()),
1248                ),
1249            };
1250
1251        if let Some(secondary_changed_range) = secondary_diff_change
1252            && let (Some(secondary_hunk_range), Some(secondary_base_range)) =
1253                old_snapshot.range_to_hunk_range(secondary_changed_range, buffer)
1254        {
1255            if let Some(range) = &mut changed_range {
1256                range.start = *secondary_hunk_range.start.min(&range.start, buffer);
1257                range.end = *secondary_hunk_range.end.max(&range.end, buffer);
1258            } else {
1259                changed_range = Some(secondary_hunk_range);
1260            }
1261
1262            if let Some(base_text_range) = &mut base_text_changed_range {
1263                base_text_range.start = secondary_base_range.start.min(base_text_range.start);
1264                base_text_range.end = secondary_base_range.end.max(base_text_range.end);
1265            } else {
1266                base_text_changed_range = Some(secondary_base_range);
1267            }
1268        }
1269
1270        let state = &mut self.inner;
1271        state.base_text_exists = new_state.base_text_exists;
1272        if cfg!(debug_assertions) {
1273            for hunk in new_state.hunks.iter() {
1274                new_state.base_text.get(hunk.diff_base_byte_range.clone());
1275            }
1276        }
1277        if base_text_changed {
1278            state.base_text.update(cx, |base_text, cx| {
1279                base_text.set_text(dbg!(new_state.base_text.clone()), cx);
1280            })
1281        }
1282        state.hunks = new_state.hunks;
1283        if cfg!(debug_assertions) {
1284            pretty_assertions::assert_eq!(
1285                state.base_text.read(cx).snapshot().text().as_str(),
1286                new_state.base_text.as_ref()
1287            );
1288            for hunk in state.hunks.iter() {
1289                state
1290                    .base_text
1291                    .read(cx)
1292                    .snapshot()
1293                    .text_summary_for_range::<text::TextSummary, _>(
1294                        hunk.diff_base_byte_range.clone(),
1295                    );
1296            }
1297        }
1298        if base_text_changed || clear_pending_hunks {
1299            if let Some((first, last)) = state.pending_hunks.first().zip(state.pending_hunks.last())
1300            {
1301                if let Some(range) = &mut changed_range {
1302                    range.start = *range.start.min(&first.buffer_range.start, buffer);
1303                    range.end = *range.end.max(&last.buffer_range.end, buffer);
1304                } else {
1305                    changed_range = Some(first.buffer_range.start..last.buffer_range.end);
1306                }
1307
1308                if let Some(base_text_range) = &mut base_text_changed_range {
1309                    base_text_range.start =
1310                        base_text_range.start.min(first.diff_base_byte_range.start);
1311                    base_text_range.end = base_text_range.end.max(last.diff_base_byte_range.end);
1312                } else {
1313                    base_text_changed_range =
1314                        Some(first.diff_base_byte_range.start..last.diff_base_byte_range.end);
1315                }
1316            }
1317            state.pending_hunks = SumTree::new(buffer);
1318        }
1319
1320        cx.emit(BufferDiffEvent::DiffChanged {
1321            changed_range: changed_range.clone(),
1322            base_text_changed_range,
1323        });
1324        changed_range
1325    }
1326
1327    pub fn base_text(&self, cx: &App) -> language::BufferSnapshot {
1328        self.inner.base_text.read(cx).snapshot()
1329    }
1330
1331    pub fn base_text_exists(&self) -> bool {
1332        self.inner.base_text_exists
1333    }
1334
1335    pub fn snapshot(&self, cx: &App) -> BufferDiffSnapshot {
1336        BufferDiffSnapshot {
1337            inner: BufferDiffInner {
1338                hunks: self.inner.hunks.clone(),
1339                pending_hunks: self.inner.pending_hunks.clone(),
1340                base_text: self.inner.base_text.read(cx).snapshot(),
1341                base_text_exists: self.inner.base_text_exists,
1342            },
1343            secondary_diff: self
1344                .secondary_diff
1345                .as_ref()
1346                .map(|diff| Box::new(diff.read(cx).snapshot(cx))),
1347        }
1348    }
1349
1350    /// Used in cases where the change set isn't derived from git.
1351    pub fn set_base_text(
1352        &mut self,
1353        base_text: Option<Arc<str>>,
1354        language: Option<Arc<Language>>,
1355        buffer: text::BufferSnapshot,
1356        cx: &mut Context<Self>,
1357    ) -> oneshot::Receiver<()> {
1358        let (tx, rx) = oneshot::channel();
1359        let complete_on_drop = util::defer(|| {
1360            tx.send(()).ok();
1361        });
1362        cx.spawn(async move |this, cx| {
1363            let Some(state) = this
1364                .update(cx, |this, cx| {
1365                    this.update_diff(buffer.clone(), base_text, true, language, cx)
1366                })
1367                .log_err()
1368            else {
1369                return;
1370            };
1371            let state = state.await;
1372            this.update(cx, |this, cx| {
1373                this.set_snapshot(state, &buffer, true, cx);
1374            })
1375            .log_err();
1376            drop(complete_on_drop)
1377        })
1378        .detach();
1379        rx
1380    }
1381
1382    pub fn base_text_string(&self, cx: &App) -> Option<String> {
1383        self.inner
1384            .base_text_exists
1385            .then(|| self.inner.base_text.read(cx).text())
1386    }
1387
1388    #[cfg(any(test, feature = "test-support"))]
1389    pub fn recalculate_diff_sync(&mut self, buffer: text::BufferSnapshot, cx: &mut Context<Self>) {
1390        let language = self.base_text(cx).language().cloned();
1391        let base_text = self.base_text_string(cx).map(|s| s.as_str().into());
1392        let fut = self.update_diff(buffer.clone(), base_text, false, language, cx);
1393        let snapshot = cx.background_executor().block(fut);
1394        self.set_snapshot(snapshot, &buffer, false, cx);
1395    }
1396}
1397
1398impl DiffHunk {
1399    pub fn is_created_file(&self) -> bool {
1400        self.diff_base_byte_range == (0..0)
1401            && self.buffer_range.start.is_min()
1402            && self.buffer_range.end.is_max()
1403    }
1404
1405    pub fn status(&self) -> DiffHunkStatus {
1406        let kind = if self.buffer_range.start == self.buffer_range.end {
1407            DiffHunkStatusKind::Deleted
1408        } else if self.diff_base_byte_range.is_empty() {
1409            DiffHunkStatusKind::Added
1410        } else {
1411            DiffHunkStatusKind::Modified
1412        };
1413        DiffHunkStatus {
1414            kind,
1415            secondary: self.secondary_status,
1416        }
1417    }
1418}
1419
1420impl DiffHunkStatus {
1421    pub fn has_secondary_hunk(&self) -> bool {
1422        matches!(
1423            self.secondary,
1424            DiffHunkSecondaryStatus::HasSecondaryHunk
1425                | DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
1426                | DiffHunkSecondaryStatus::OverlapsWithSecondaryHunk
1427        )
1428    }
1429
1430    pub fn is_pending(&self) -> bool {
1431        matches!(
1432            self.secondary,
1433            DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
1434                | DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
1435        )
1436    }
1437
1438    pub fn is_deleted(&self) -> bool {
1439        self.kind == DiffHunkStatusKind::Deleted
1440    }
1441
1442    pub fn is_added(&self) -> bool {
1443        self.kind == DiffHunkStatusKind::Added
1444    }
1445
1446    pub fn is_modified(&self) -> bool {
1447        self.kind == DiffHunkStatusKind::Modified
1448    }
1449
1450    pub fn added(secondary: DiffHunkSecondaryStatus) -> Self {
1451        Self {
1452            kind: DiffHunkStatusKind::Added,
1453            secondary,
1454        }
1455    }
1456
1457    pub fn modified(secondary: DiffHunkSecondaryStatus) -> Self {
1458        Self {
1459            kind: DiffHunkStatusKind::Modified,
1460            secondary,
1461        }
1462    }
1463
1464    pub fn deleted(secondary: DiffHunkSecondaryStatus) -> Self {
1465        Self {
1466            kind: DiffHunkStatusKind::Deleted,
1467            secondary,
1468        }
1469    }
1470
1471    pub fn deleted_none() -> Self {
1472        Self {
1473            kind: DiffHunkStatusKind::Deleted,
1474            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1475        }
1476    }
1477
1478    pub fn added_none() -> Self {
1479        Self {
1480            kind: DiffHunkStatusKind::Added,
1481            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1482        }
1483    }
1484
1485    pub fn modified_none() -> Self {
1486        Self {
1487            kind: DiffHunkStatusKind::Modified,
1488            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1489        }
1490    }
1491}
1492
1493#[cfg(any(test, feature = "test-support"))]
1494#[track_caller]
1495pub fn assert_hunks<ExpectedText, HunkIter>(
1496    diff_hunks: HunkIter,
1497    buffer: &text::BufferSnapshot,
1498    diff_base: &str,
1499    // Line range, deleted, added, status
1500    expected_hunks: &[(Range<u32>, ExpectedText, ExpectedText, DiffHunkStatus)],
1501) where
1502    HunkIter: Iterator<Item = DiffHunk>,
1503    ExpectedText: AsRef<str>,
1504{
1505    let actual_hunks = diff_hunks
1506        .map(|hunk| {
1507            (
1508                hunk.range.clone(),
1509                &diff_base[hunk.diff_base_byte_range.clone()],
1510                buffer
1511                    .text_for_range(hunk.range.clone())
1512                    .collect::<String>(),
1513                hunk.status(),
1514            )
1515        })
1516        .collect::<Vec<_>>();
1517
1518    let expected_hunks: Vec<_> = expected_hunks
1519        .iter()
1520        .map(|(line_range, deleted_text, added_text, status)| {
1521            (
1522                Point::new(line_range.start, 0)..Point::new(line_range.end, 0),
1523                deleted_text.as_ref(),
1524                added_text.as_ref().to_string(),
1525                *status,
1526            )
1527        })
1528        .collect();
1529
1530    pretty_assertions::assert_eq!(actual_hunks, expected_hunks);
1531}
1532
1533#[cfg(test)]
1534mod tests {
1535    use std::fmt::Write as _;
1536
1537    use super::*;
1538    use gpui::TestAppContext;
1539    use pretty_assertions::{assert_eq, assert_ne};
1540    use rand::{Rng as _, rngs::StdRng};
1541    use text::{Buffer, BufferId, ReplicaId, Rope};
1542    use unindent::Unindent as _;
1543    use util::test::marked_text_ranges;
1544
1545    #[ctor::ctor]
1546    fn init_logger() {
1547        zlog::init_test();
1548    }
1549
1550    #[gpui::test]
1551    async fn test_buffer_diff_simple(cx: &mut gpui::TestAppContext) {
1552        let diff_base = "
1553            one
1554            two
1555            three
1556        "
1557        .unindent();
1558
1559        let buffer_text = "
1560            one
1561            HELLO
1562            three
1563        "
1564        .unindent();
1565
1566        let mut buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1567        let mut diff = BufferDiffSnapshot::new_sync(buffer.clone(), diff_base.clone(), cx);
1568        assert_hunks(
1569            diff.hunks_intersecting_range(
1570                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1571                &buffer,
1572            ),
1573            &buffer,
1574            &diff_base,
1575            &[(1..2, "two\n", "HELLO\n", DiffHunkStatus::modified_none())],
1576        );
1577
1578        buffer.edit([(0..0, "point five\n")]);
1579        diff = BufferDiffSnapshot::new_sync(buffer.clone(), diff_base.clone(), cx);
1580        assert_hunks(
1581            diff.hunks_intersecting_range(
1582                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1583                &buffer,
1584            ),
1585            &buffer,
1586            &diff_base,
1587            &[
1588                (0..1, "", "point five\n", DiffHunkStatus::added_none()),
1589                (2..3, "two\n", "HELLO\n", DiffHunkStatus::modified_none()),
1590            ],
1591        );
1592
1593        diff = cx.update(|cx| BufferDiff::new(&buffer, cx).snapshot(cx));
1594        assert_hunks::<&str, _>(
1595            diff.hunks_intersecting_range(
1596                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1597                &buffer,
1598            ),
1599            &buffer,
1600            &diff_base,
1601            &[],
1602        );
1603    }
1604
1605    #[gpui::test]
1606    async fn test_buffer_diff_with_secondary(cx: &mut gpui::TestAppContext) {
1607        let head_text = "
1608            zero
1609            one
1610            two
1611            three
1612            four
1613            five
1614            six
1615            seven
1616            eight
1617            nine
1618        "
1619        .unindent();
1620
1621        let index_text = "
1622            zero
1623            one
1624            TWO
1625            three
1626            FOUR
1627            five
1628            six
1629            seven
1630            eight
1631            NINE
1632        "
1633        .unindent();
1634
1635        let buffer_text = "
1636            zero
1637            one
1638            TWO
1639            three
1640            FOUR
1641            FIVE
1642            six
1643            SEVEN
1644            eight
1645            nine
1646        "
1647        .unindent();
1648
1649        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1650        let unstaged_diff = BufferDiffSnapshot::new_sync(buffer.clone(), index_text, cx);
1651        let mut uncommitted_diff =
1652            BufferDiffSnapshot::new_sync(buffer.clone(), head_text.clone(), cx);
1653        uncommitted_diff.secondary_diff = Some(Box::new(unstaged_diff));
1654
1655        let expected_hunks = vec![
1656            (2..3, "two\n", "TWO\n", DiffHunkStatus::modified_none()),
1657            (
1658                4..6,
1659                "four\nfive\n",
1660                "FOUR\nFIVE\n",
1661                DiffHunkStatus::modified(DiffHunkSecondaryStatus::OverlapsWithSecondaryHunk),
1662            ),
1663            (
1664                7..8,
1665                "seven\n",
1666                "SEVEN\n",
1667                DiffHunkStatus::modified(DiffHunkSecondaryStatus::HasSecondaryHunk),
1668            ),
1669        ];
1670
1671        assert_hunks(
1672            uncommitted_diff.hunks_intersecting_range(
1673                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1674                &buffer,
1675            ),
1676            &buffer,
1677            &head_text,
1678            &expected_hunks,
1679        );
1680    }
1681
1682    #[gpui::test]
1683    async fn test_buffer_diff_range(cx: &mut TestAppContext) {
1684        let diff_base = "
1685            one
1686            two
1687            three
1688            four
1689            five
1690            six
1691            seven
1692            eight
1693            nine
1694            ten
1695        "
1696        .unindent();
1697
1698        let buffer_text = "
1699            A
1700            one
1701            B
1702            two
1703            C
1704            three
1705            HELLO
1706            four
1707            five
1708            SIXTEEN
1709            seven
1710            eight
1711            WORLD
1712            nine
1713
1714            ten
1715
1716        "
1717        .unindent();
1718
1719        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1720        let diff = BufferDiffSnapshot::new_sync(buffer.snapshot(), diff_base.clone(), cx);
1721        assert_eq!(
1722            diff.hunks_intersecting_range(
1723                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1724                &buffer
1725            )
1726            .count(),
1727            8
1728        );
1729
1730        assert_hunks(
1731            diff.hunks_intersecting_range(
1732                buffer.anchor_before(Point::new(7, 0))..buffer.anchor_before(Point::new(12, 0)),
1733                &buffer,
1734            ),
1735            &buffer,
1736            &diff_base,
1737            &[
1738                (6..7, "", "HELLO\n", DiffHunkStatus::added_none()),
1739                (9..10, "six\n", "SIXTEEN\n", DiffHunkStatus::modified_none()),
1740                (12..13, "", "WORLD\n", DiffHunkStatus::added_none()),
1741            ],
1742        );
1743    }
1744
1745    #[gpui::test]
1746    async fn test_stage_hunk(cx: &mut TestAppContext) {
1747        struct Example {
1748            name: &'static str,
1749            head_text: String,
1750            index_text: String,
1751            buffer_marked_text: String,
1752            final_index_text: String,
1753        }
1754
1755        let table = [
1756            Example {
1757                name: "uncommitted hunk straddles end of unstaged hunk",
1758                head_text: "
1759                    one
1760                    two
1761                    three
1762                    four
1763                    five
1764                "
1765                .unindent(),
1766                index_text: "
1767                    one
1768                    TWO_HUNDRED
1769                    three
1770                    FOUR_HUNDRED
1771                    five
1772                "
1773                .unindent(),
1774                buffer_marked_text: "
1775                    ZERO
1776                    one
1777                    two
1778                    «THREE_HUNDRED
1779                    FOUR_HUNDRED»
1780                    five
1781                    SIX
1782                "
1783                .unindent(),
1784                final_index_text: "
1785                    one
1786                    two
1787                    THREE_HUNDRED
1788                    FOUR_HUNDRED
1789                    five
1790                "
1791                .unindent(),
1792            },
1793            Example {
1794                name: "uncommitted hunk straddles start of unstaged hunk",
1795                head_text: "
1796                    one
1797                    two
1798                    three
1799                    four
1800                    five
1801                "
1802                .unindent(),
1803                index_text: "
1804                    one
1805                    TWO_HUNDRED
1806                    three
1807                    FOUR_HUNDRED
1808                    five
1809                "
1810                .unindent(),
1811                buffer_marked_text: "
1812                    ZERO
1813                    one
1814                    «TWO_HUNDRED
1815                    THREE_HUNDRED»
1816                    four
1817                    five
1818                    SIX
1819                "
1820                .unindent(),
1821                final_index_text: "
1822                    one
1823                    TWO_HUNDRED
1824                    THREE_HUNDRED
1825                    four
1826                    five
1827                "
1828                .unindent(),
1829            },
1830            Example {
1831                name: "uncommitted hunk strictly contains unstaged hunks",
1832                head_text: "
1833                    one
1834                    two
1835                    three
1836                    four
1837                    five
1838                    six
1839                    seven
1840                "
1841                .unindent(),
1842                index_text: "
1843                    one
1844                    TWO
1845                    THREE
1846                    FOUR
1847                    FIVE
1848                    SIX
1849                    seven
1850                "
1851                .unindent(),
1852                buffer_marked_text: "
1853                    one
1854                    TWO
1855                    «THREE_HUNDRED
1856                    FOUR
1857                    FIVE_HUNDRED»
1858                    SIX
1859                    seven
1860                "
1861                .unindent(),
1862                final_index_text: "
1863                    one
1864                    TWO
1865                    THREE_HUNDRED
1866                    FOUR
1867                    FIVE_HUNDRED
1868                    SIX
1869                    seven
1870                "
1871                .unindent(),
1872            },
1873            Example {
1874                name: "uncommitted deletion hunk",
1875                head_text: "
1876                    one
1877                    two
1878                    three
1879                    four
1880                    five
1881                "
1882                .unindent(),
1883                index_text: "
1884                    one
1885                    two
1886                    three
1887                    four
1888                    five
1889                "
1890                .unindent(),
1891                buffer_marked_text: "
1892                    one
1893                    ˇfive
1894                "
1895                .unindent(),
1896                final_index_text: "
1897                    one
1898                    five
1899                "
1900                .unindent(),
1901            },
1902            Example {
1903                name: "one unstaged hunk that contains two uncommitted hunks",
1904                head_text: "
1905                    one
1906                    two
1907
1908                    three
1909                    four
1910                "
1911                .unindent(),
1912                index_text: "
1913                    one
1914                    two
1915                    three
1916                    four
1917                "
1918                .unindent(),
1919                buffer_marked_text: "
1920                    «one
1921
1922                    three // modified
1923                    four»
1924                "
1925                .unindent(),
1926                final_index_text: "
1927                    one
1928
1929                    three // modified
1930                    four
1931                "
1932                .unindent(),
1933            },
1934            Example {
1935                name: "one uncommitted hunk that contains two unstaged hunks",
1936                head_text: "
1937                    one
1938                    two
1939                    three
1940                    four
1941                    five
1942                "
1943                .unindent(),
1944                index_text: "
1945                    ZERO
1946                    one
1947                    TWO
1948                    THREE
1949                    FOUR
1950                    five
1951                "
1952                .unindent(),
1953                buffer_marked_text: "
1954                    «one
1955                    TWO_HUNDRED
1956                    THREE
1957                    FOUR_HUNDRED
1958                    five»
1959                "
1960                .unindent(),
1961                final_index_text: "
1962                    ZERO
1963                    one
1964                    TWO_HUNDRED
1965                    THREE
1966                    FOUR_HUNDRED
1967                    five
1968                "
1969                .unindent(),
1970            },
1971        ];
1972
1973        for example in table {
1974            let (buffer_text, ranges) = marked_text_ranges(&example.buffer_marked_text, false);
1975            let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1976            let hunk_range =
1977                buffer.anchor_before(ranges[0].start)..buffer.anchor_before(ranges[0].end);
1978
1979            let unstaged_diff =
1980                cx.new(|cx| BufferDiff::new_with_base_text(&example.index_text, &buffer, cx));
1981
1982            let uncommitted_diff = cx.new(|cx| {
1983                let mut diff = BufferDiff::new_with_base_text(&example.head_text, &buffer, cx);
1984                diff.set_secondary_diff(unstaged_diff);
1985                diff
1986            });
1987
1988            uncommitted_diff.update(cx, |diff, cx| {
1989                let hunks = diff
1990                    .snapshot(cx)
1991                    .hunks_intersecting_range(hunk_range.clone(), &buffer)
1992                    .collect::<Vec<_>>();
1993                for hunk in &hunks {
1994                    assert_ne!(
1995                        hunk.secondary_status,
1996                        DiffHunkSecondaryStatus::NoSecondaryHunk
1997                    )
1998                }
1999
2000                let new_index_text = diff
2001                    .stage_or_unstage_hunks(true, &hunks, &buffer, true, cx)
2002                    .unwrap()
2003                    .to_string();
2004
2005                let hunks = diff
2006                    .snapshot(cx)
2007                    .hunks_intersecting_range(hunk_range.clone(), &buffer)
2008                    .collect::<Vec<_>>();
2009                for hunk in &hunks {
2010                    assert_eq!(
2011                        hunk.secondary_status,
2012                        DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
2013                    )
2014                }
2015
2016                pretty_assertions::assert_eq!(
2017                    new_index_text,
2018                    example.final_index_text,
2019                    "example: {}",
2020                    example.name
2021                );
2022            });
2023        }
2024    }
2025
2026    #[gpui::test]
2027    async fn test_toggling_stage_and_unstage_same_hunk(cx: &mut TestAppContext) {
2028        let head_text = "
2029            one
2030            two
2031            three
2032        "
2033        .unindent();
2034        let index_text = head_text.clone();
2035        let buffer_text = "
2036            one
2037            three
2038        "
2039        .unindent();
2040
2041        let buffer = Buffer::new(
2042            ReplicaId::LOCAL,
2043            BufferId::new(1).unwrap(),
2044            buffer_text.clone(),
2045        );
2046        let unstaged_diff = cx.new(|cx| BufferDiff::new_with_base_text(&index_text, &buffer, cx));
2047        let uncommitted_diff = cx.new(|cx| {
2048            let mut diff = BufferDiff::new_with_base_text(&head_text, &buffer, cx);
2049            diff.set_secondary_diff(unstaged_diff.clone());
2050            diff
2051        });
2052
2053        uncommitted_diff.update(cx, |diff, cx| {
2054            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2055
2056            let new_index_text = diff
2057                .stage_or_unstage_hunks(true, std::slice::from_ref(&hunk), &buffer, true, cx)
2058                .unwrap()
2059                .to_string();
2060            assert_eq!(new_index_text, buffer_text);
2061
2062            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2063            assert_eq!(
2064                hunk.secondary_status,
2065                DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
2066            );
2067
2068            let index_text = diff
2069                .stage_or_unstage_hunks(false, &[hunk], &buffer, true, cx)
2070                .unwrap()
2071                .to_string();
2072            assert_eq!(index_text, head_text);
2073
2074            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2075            // optimistically unstaged (fine, could also be HasSecondaryHunk)
2076            assert_eq!(
2077                hunk.secondary_status,
2078                DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
2079            );
2080        });
2081    }
2082
2083    #[gpui::test]
2084    async fn test_buffer_diff_compare(cx: &mut TestAppContext) {
2085        let base_text = "
2086            zero
2087            one
2088            two
2089            three
2090            four
2091            five
2092            six
2093            seven
2094            eight
2095            nine
2096        "
2097        .unindent();
2098
2099        let buffer_text_1 = "
2100            one
2101            three
2102            four
2103            five
2104            SIX
2105            seven
2106            eight
2107            NINE
2108        "
2109        .unindent();
2110
2111        let mut buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text_1);
2112
2113        let empty_diff = cx.update(|cx| BufferDiff::new(&buffer, cx).snapshot(cx));
2114        let diff_1 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2115        // FIXME assert the other half of the range
2116        let (range, base_text_range) =
2117            compare_hunks(&diff_1.inner.hunks, &empty_diff.inner.hunks, &buffer);
2118        let range = range.unwrap();
2119        assert_eq!(range.to_point(&buffer), Point::new(0, 0)..Point::new(8, 0));
2120
2121        // Edit does not affect the diff.
2122        buffer.edit_via_marked_text(
2123            &"
2124                one
2125                three
2126                four
2127                five
2128                «SIX.5»
2129                seven
2130                eight
2131                NINE
2132            "
2133            .unindent(),
2134        );
2135        let diff_2 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2136        assert_eq!(
2137            (None, None),
2138            compare_hunks(&diff_2.inner.hunks, &diff_1.inner.hunks, &buffer)
2139        );
2140
2141        // Edit turns a deletion hunk into a modification.
2142        buffer.edit_via_marked_text(
2143            &"
2144                one
2145                «THREE»
2146                four
2147                five
2148                SIX.5
2149                seven
2150                eight
2151                NINE
2152            "
2153            .unindent(),
2154        );
2155        let diff_3 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2156        // FIXME assert the other range
2157        let (range, base_text_range) =
2158            compare_hunks(&diff_3.inner.hunks, &diff_2.inner.hunks, &buffer);
2159        let range = range.unwrap();
2160        assert_eq!(range.to_point(&buffer), Point::new(1, 0)..Point::new(2, 0));
2161
2162        // Edit turns a modification hunk into a deletion.
2163        buffer.edit_via_marked_text(
2164            &"
2165                one
2166                THREE
2167                four
2168                five«»
2169                seven
2170                eight
2171                NINE
2172            "
2173            .unindent(),
2174        );
2175        let diff_4 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2176        let (range, base_text_range) =
2177            compare_hunks(&diff_4.inner.hunks, &diff_3.inner.hunks, &buffer);
2178        let range = range.unwrap();
2179        assert_eq!(range.to_point(&buffer), Point::new(3, 4)..Point::new(4, 0));
2180
2181        // Edit introduces a new insertion hunk.
2182        buffer.edit_via_marked_text(
2183            &"
2184                one
2185                THREE
2186                four«
2187                FOUR.5
2188                »five
2189                seven
2190                eight
2191                NINE
2192            "
2193            .unindent(),
2194        );
2195        let diff_5 = BufferDiffSnapshot::new_sync(buffer.snapshot(), base_text.clone(), cx);
2196        let (range, base_text_range) =
2197            compare_hunks(&diff_5.inner.hunks, &diff_4.inner.hunks, &buffer);
2198        let range = range.unwrap();
2199        assert_eq!(range.to_point(&buffer), Point::new(3, 0)..Point::new(4, 0));
2200
2201        // Edit removes a hunk.
2202        buffer.edit_via_marked_text(
2203            &"
2204                one
2205                THREE
2206                four
2207                FOUR.5
2208                five
2209                seven
2210                eight
2211                «nine»
2212            "
2213            .unindent(),
2214        );
2215        let diff_6 = BufferDiffSnapshot::new_sync(buffer.snapshot(), base_text, cx);
2216        let (range, base_text_range) =
2217            compare_hunks(&diff_6.inner.hunks, &diff_5.inner.hunks, &buffer);
2218        let range = range.unwrap();
2219        assert_eq!(range.to_point(&buffer), Point::new(7, 0)..Point::new(8, 0));
2220    }
2221
2222    #[gpui::test(iterations = 100)]
2223    async fn test_staging_and_unstaging_hunks(cx: &mut TestAppContext, mut rng: StdRng) {
2224        fn gen_line(rng: &mut StdRng) -> String {
2225            if rng.random_bool(0.2) {
2226                "\n".to_owned()
2227            } else {
2228                let c = rng.random_range('A'..='Z');
2229                format!("{c}{c}{c}\n")
2230            }
2231        }
2232
2233        fn gen_working_copy(rng: &mut StdRng, head: &str) -> String {
2234            let mut old_lines = {
2235                let mut old_lines = Vec::new();
2236                let old_lines_iter = head.lines();
2237                for line in old_lines_iter {
2238                    assert!(!line.ends_with("\n"));
2239                    old_lines.push(line.to_owned());
2240                }
2241                if old_lines.last().is_some_and(|line| line.is_empty()) {
2242                    old_lines.pop();
2243                }
2244                old_lines.into_iter()
2245            };
2246            let mut result = String::new();
2247            let unchanged_count = rng.random_range(0..=old_lines.len());
2248            result +=
2249                &old_lines
2250                    .by_ref()
2251                    .take(unchanged_count)
2252                    .fold(String::new(), |mut s, line| {
2253                        writeln!(&mut s, "{line}").unwrap();
2254                        s
2255                    });
2256            while old_lines.len() > 0 {
2257                let deleted_count = rng.random_range(0..=old_lines.len());
2258                let _advance = old_lines
2259                    .by_ref()
2260                    .take(deleted_count)
2261                    .map(|line| line.len() + 1)
2262                    .sum::<usize>();
2263                let minimum_added = if deleted_count == 0 { 1 } else { 0 };
2264                let added_count = rng.random_range(minimum_added..=5);
2265                let addition = (0..added_count).map(|_| gen_line(rng)).collect::<String>();
2266                result += &addition;
2267
2268                if old_lines.len() > 0 {
2269                    let blank_lines = old_lines.clone().take_while(|line| line.is_empty()).count();
2270                    if blank_lines == old_lines.len() {
2271                        break;
2272                    };
2273                    let unchanged_count =
2274                        rng.random_range((blank_lines + 1).max(1)..=old_lines.len());
2275                    result += &old_lines.by_ref().take(unchanged_count).fold(
2276                        String::new(),
2277                        |mut s, line| {
2278                            writeln!(&mut s, "{line}").unwrap();
2279                            s
2280                        },
2281                    );
2282                }
2283            }
2284            result
2285        }
2286
2287        fn uncommitted_diff(
2288            working_copy: &language::BufferSnapshot,
2289            index_text: &Rope,
2290            head_text: String,
2291            cx: &mut TestAppContext,
2292        ) -> Entity<BufferDiff> {
2293            let secondary = cx.new(|cx| {
2294                BufferDiff::new_with_base_text(&index_text.to_string(), &working_copy.text, cx)
2295            });
2296            cx.new(|cx| {
2297                let mut diff = BufferDiff::new_with_base_text(&head_text, &working_copy.text, cx);
2298                diff.secondary_diff = Some(secondary);
2299                diff
2300            })
2301        }
2302
2303        let operations = std::env::var("OPERATIONS")
2304            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
2305            .unwrap_or(10);
2306
2307        let rng = &mut rng;
2308        let head_text = ('a'..='z').fold(String::new(), |mut s, c| {
2309            writeln!(&mut s, "{c}{c}{c}").unwrap();
2310            s
2311        });
2312        let working_copy = gen_working_copy(rng, &head_text);
2313        let working_copy = cx.new(|cx| {
2314            language::Buffer::local_normalized(
2315                Rope::from(working_copy.as_str()),
2316                text::LineEnding::default(),
2317                cx,
2318            )
2319        });
2320        let working_copy = working_copy.read_with(cx, |working_copy, _| working_copy.snapshot());
2321        let mut index_text = if rng.random() {
2322            Rope::from(head_text.as_str())
2323        } else {
2324            working_copy.as_rope().clone()
2325        };
2326
2327        let mut diff = uncommitted_diff(&working_copy, &index_text, head_text.clone(), cx);
2328        let mut hunks = diff.update(cx, |diff, cx| {
2329            diff.snapshot(cx)
2330                .hunks_intersecting_range(
2331                    Anchor::min_max_range_for_buffer(diff.buffer_id),
2332                    &working_copy,
2333                )
2334                .collect::<Vec<_>>()
2335        });
2336        if hunks.is_empty() {
2337            return;
2338        }
2339
2340        for _ in 0..operations {
2341            let i = rng.random_range(0..hunks.len());
2342            let hunk = &mut hunks[i];
2343            let hunk_to_change = hunk.clone();
2344            let stage = match hunk.secondary_status {
2345                DiffHunkSecondaryStatus::HasSecondaryHunk => {
2346                    hunk.secondary_status = DiffHunkSecondaryStatus::NoSecondaryHunk;
2347                    true
2348                }
2349                DiffHunkSecondaryStatus::NoSecondaryHunk => {
2350                    hunk.secondary_status = DiffHunkSecondaryStatus::HasSecondaryHunk;
2351                    false
2352                }
2353                _ => unreachable!(),
2354            };
2355
2356            index_text = diff.update(cx, |diff, cx| {
2357                diff.stage_or_unstage_hunks(stage, &[hunk_to_change], &working_copy, true, cx)
2358                    .unwrap()
2359            });
2360
2361            diff = uncommitted_diff(&working_copy, &index_text, head_text.clone(), cx);
2362            let found_hunks = diff.update(cx, |diff, cx| {
2363                diff.snapshot(cx)
2364                    .hunks_intersecting_range(
2365                        Anchor::min_max_range_for_buffer(diff.buffer_id),
2366                        &working_copy,
2367                    )
2368                    .collect::<Vec<_>>()
2369            });
2370            assert_eq!(hunks.len(), found_hunks.len());
2371
2372            for (expected_hunk, found_hunk) in hunks.iter().zip(&found_hunks) {
2373                assert_eq!(
2374                    expected_hunk.buffer_range.to_point(&working_copy),
2375                    found_hunk.buffer_range.to_point(&working_copy)
2376                );
2377                assert_eq!(
2378                    expected_hunk.diff_base_byte_range,
2379                    found_hunk.diff_base_byte_range
2380                );
2381                assert_eq!(expected_hunk.secondary_status, found_hunk.secondary_status);
2382            }
2383            hunks = found_hunks;
2384        }
2385    }
2386
2387    #[gpui::test]
2388    async fn test_row_to_base_text_row(cx: &mut TestAppContext) {
2389        let base_text = "
2390            zero
2391            one
2392            two
2393            three
2394            four
2395            five
2396            six
2397            seven
2398            eight
2399        "
2400        .unindent();
2401        let buffer_text = "
2402            zero
2403            ONE
2404            two
2405            NINE
2406            five
2407            seven
2408        "
2409        .unindent();
2410
2411        //   zero
2412        // - one
2413        // + ONE
2414        //   two
2415        // - three
2416        // - four
2417        // + NINE
2418        //   five
2419        // - six
2420        //   seven
2421        // + eight
2422
2423        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
2424        let buffer_snapshot = buffer.snapshot();
2425        let diff = BufferDiffSnapshot::new_sync(buffer_snapshot.clone(), base_text, cx);
2426        let expected_results = [
2427            // don't format me
2428            (0, 0),
2429            (1, 2),
2430            (2, 2),
2431            (3, 5),
2432            (4, 5),
2433            (5, 7),
2434            (6, 9),
2435        ];
2436        for (buffer_row, expected) in expected_results {
2437            assert_eq!(
2438                diff.row_to_base_text_row(buffer_row, &buffer_snapshot),
2439                expected,
2440                "{buffer_row}"
2441            );
2442        }
2443    }
2444}