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 inner = executor.block(this.update_diff(
1089            buffer.clone(),
1090            Some(Arc::from(base_text)),
1091            true,
1092            None,
1093            cx,
1094        ));
1095        this.set_snapshot(inner, &buffer, true, cx);
1096        this
1097    }
1098
1099    pub fn set_secondary_diff(&mut self, diff: Entity<BufferDiff>) {
1100        self.secondary_diff = Some(diff);
1101    }
1102
1103    pub fn secondary_diff(&self) -> Option<Entity<BufferDiff>> {
1104        self.secondary_diff.clone()
1105    }
1106
1107    pub fn clear_pending_hunks(&mut self, cx: &mut Context<Self>) {
1108        if self.secondary_diff.is_some() {
1109            self.inner.pending_hunks = SumTree::from_summary(DiffHunkSummary {
1110                buffer_range: Anchor::min_min_range_for_buffer(self.buffer_id),
1111                diff_base_byte_range: 0..0,
1112            });
1113            cx.emit(BufferDiffEvent::DiffChanged {
1114                changed_range: Some(Anchor::min_max_range_for_buffer(self.buffer_id)),
1115                base_text_changed_range: Some(0..self.base_text(cx).len()),
1116            });
1117        }
1118    }
1119
1120    pub fn stage_or_unstage_hunks(
1121        &mut self,
1122        stage: bool,
1123        hunks: &[DiffHunk],
1124        buffer: &text::BufferSnapshot,
1125        file_exists: bool,
1126        cx: &mut Context<Self>,
1127    ) -> Option<Rope> {
1128        let new_index_text = self
1129            .secondary_diff
1130            .as_ref()?
1131            .update(cx, |secondary_diff, cx| {
1132                self.inner.stage_or_unstage_hunks_impl(
1133                    &secondary_diff.inner,
1134                    stage,
1135                    hunks,
1136                    buffer,
1137                    file_exists,
1138                    cx,
1139                )
1140            });
1141
1142        cx.emit(BufferDiffEvent::HunksStagedOrUnstaged(
1143            new_index_text.clone(),
1144        ));
1145        if let Some((first, last)) = hunks.first().zip(hunks.last()) {
1146            let changed_range = first.buffer_range.start..last.buffer_range.end;
1147            let base_text_changed_range =
1148                first.diff_base_byte_range.start..last.diff_base_byte_range.end;
1149            cx.emit(BufferDiffEvent::DiffChanged {
1150                changed_range: Some(changed_range),
1151                base_text_changed_range: Some(base_text_changed_range),
1152            });
1153        }
1154        new_index_text
1155    }
1156
1157    pub fn update_diff(
1158        &self,
1159        buffer: text::BufferSnapshot,
1160        base_text: Option<Arc<str>>,
1161        base_text_changed: bool,
1162        language: Option<Arc<Language>>,
1163        cx: &App,
1164    ) -> Task<BufferDiffInner<Arc<str>>> {
1165        let prev_base_text = self.base_text(cx).as_rope().clone();
1166        let diff_options = build_diff_options(
1167            None,
1168            language.as_ref().map(|l| l.name()),
1169            language.as_ref().map(|l| l.default_scope()),
1170            cx,
1171        );
1172
1173        cx.background_executor()
1174            .spawn_labeled(*CALCULATE_DIFF_TASK, async move {
1175                let base_text_rope = if let Some(base_text) = &base_text {
1176                    if base_text_changed {
1177                        Rope::from(base_text.as_ref())
1178                    } else {
1179                        prev_base_text
1180                    }
1181                } else {
1182                    Rope::new()
1183                };
1184                let base_text_exists = base_text.is_some();
1185                let hunks = compute_hunks(
1186                    base_text
1187                        .clone()
1188                        .map(|base_text| (base_text, base_text_rope.clone())),
1189                    buffer.clone(),
1190                    diff_options,
1191                );
1192                BufferDiffInner {
1193                    base_text: base_text.unwrap_or_default(),
1194                    hunks,
1195                    base_text_exists,
1196                    pending_hunks: SumTree::new(&buffer),
1197                }
1198            })
1199    }
1200
1201    pub fn language_changed(&mut self, cx: &mut Context<Self>) {
1202        cx.emit(BufferDiffEvent::LanguageChanged);
1203    }
1204
1205    // FIXME name
1206    pub fn set_snapshot(
1207        &mut self,
1208        new_state: BufferDiffInner<Arc<str>>,
1209        buffer: &text::BufferSnapshot,
1210        base_text_changed: bool,
1211        cx: &mut Context<Self>,
1212    ) -> Option<Range<Anchor>> {
1213        self.set_snapshot_with_secondary(new_state, buffer, None, base_text_changed, false, cx)
1214    }
1215
1216    // FIXME name
1217    pub fn set_snapshot_with_secondary(
1218        &mut self,
1219        new_state: BufferDiffInner<Arc<str>>,
1220        buffer: &text::BufferSnapshot,
1221        secondary_diff_change: Option<Range<Anchor>>,
1222        base_text_changed: bool,
1223        clear_pending_hunks: bool,
1224        cx: &mut Context<Self>,
1225    ) -> Option<Range<Anchor>> {
1226        log::debug!("set snapshot with secondary {secondary_diff_change:?}");
1227
1228        let old_snapshot = self.snapshot(cx);
1229        let state = &mut self.inner;
1230        let (mut changed_range, mut base_text_changed_range) =
1231            match (state.base_text_exists, new_state.base_text_exists) {
1232                (false, false) => (None, None),
1233                (true, true) if !base_text_changed => {
1234                    compare_hunks(&new_state.hunks, &old_snapshot.inner.hunks, buffer)
1235                }
1236                _ => (
1237                    Some(text::Anchor::min_max_range_for_buffer(self.buffer_id)),
1238                    Some(0..new_state.base_text.len()),
1239                ),
1240            };
1241
1242        if let Some(secondary_changed_range) = secondary_diff_change
1243            && let (Some(secondary_hunk_range), Some(secondary_base_range)) =
1244                old_snapshot.range_to_hunk_range(secondary_changed_range, buffer)
1245        {
1246            if let Some(range) = &mut changed_range {
1247                range.start = *secondary_hunk_range.start.min(&range.start, buffer);
1248                range.end = *secondary_hunk_range.end.max(&range.end, buffer);
1249            } else {
1250                changed_range = Some(secondary_hunk_range);
1251            }
1252
1253            if let Some(base_text_range) = &mut base_text_changed_range {
1254                base_text_range.start = secondary_base_range.start.min(base_text_range.start);
1255                base_text_range.end = secondary_base_range.end.max(base_text_range.end);
1256            } else {
1257                base_text_changed_range = Some(secondary_base_range);
1258            }
1259        }
1260
1261        let state = &mut self.inner;
1262        state.base_text_exists = new_state.base_text_exists;
1263        if base_text_changed {
1264            state.base_text.update(cx, |base_text, cx| {
1265                base_text.set_text(new_state.base_text, cx);
1266            })
1267        }
1268        state.hunks = new_state.hunks;
1269        if base_text_changed || clear_pending_hunks {
1270            if let Some((first, last)) = state.pending_hunks.first().zip(state.pending_hunks.last())
1271            {
1272                if let Some(range) = &mut changed_range {
1273                    range.start = *range.start.min(&first.buffer_range.start, buffer);
1274                    range.end = *range.end.max(&last.buffer_range.end, buffer);
1275                } else {
1276                    changed_range = Some(first.buffer_range.start..last.buffer_range.end);
1277                }
1278
1279                if let Some(base_text_range) = &mut base_text_changed_range {
1280                    base_text_range.start =
1281                        base_text_range.start.min(first.diff_base_byte_range.start);
1282                    base_text_range.end = base_text_range.end.max(last.diff_base_byte_range.end);
1283                } else {
1284                    base_text_changed_range =
1285                        Some(first.diff_base_byte_range.start..last.diff_base_byte_range.end);
1286                }
1287            }
1288            state.pending_hunks = SumTree::new(buffer);
1289        }
1290
1291        cx.emit(BufferDiffEvent::DiffChanged {
1292            changed_range: changed_range.clone(),
1293            base_text_changed_range,
1294        });
1295        changed_range
1296    }
1297
1298    pub fn base_text(&self, cx: &App) -> language::BufferSnapshot {
1299        self.inner.base_text.read(cx).snapshot()
1300    }
1301
1302    pub fn base_text_exists(&self) -> bool {
1303        self.inner.base_text_exists
1304    }
1305
1306    pub fn snapshot(&self, cx: &App) -> BufferDiffSnapshot {
1307        BufferDiffSnapshot {
1308            inner: BufferDiffInner {
1309                hunks: self.inner.hunks.clone(),
1310                pending_hunks: self.inner.pending_hunks.clone(),
1311                base_text: self.inner.base_text.read(cx).snapshot(),
1312                base_text_exists: self.inner.base_text_exists,
1313            },
1314            secondary_diff: self
1315                .secondary_diff
1316                .as_ref()
1317                .map(|diff| Box::new(diff.read(cx).snapshot(cx))),
1318        }
1319    }
1320
1321    /// Used in cases where the change set isn't derived from git.
1322    pub fn set_base_text(
1323        &mut self,
1324        base_text: Option<Arc<str>>,
1325        language: Option<Arc<Language>>,
1326        buffer: text::BufferSnapshot,
1327        cx: &mut Context<Self>,
1328    ) -> oneshot::Receiver<()> {
1329        let (tx, rx) = oneshot::channel();
1330        let complete_on_drop = util::defer(|| {
1331            tx.send(()).ok();
1332        });
1333        cx.spawn(async move |this, cx| {
1334            let Some(state) = this
1335                .update(cx, |this, cx| {
1336                    this.update_diff(buffer.clone(), base_text, true, language, cx)
1337                })
1338                .log_err()
1339            else {
1340                return;
1341            };
1342            let state = state.await;
1343            this.update(cx, |this, cx| {
1344                this.set_snapshot(state, &buffer, true, cx);
1345            })
1346            .log_err();
1347            drop(complete_on_drop)
1348        })
1349        .detach();
1350        rx
1351    }
1352
1353    pub fn base_text_string(&self, cx: &App) -> Option<String> {
1354        self.inner
1355            .base_text_exists
1356            .then(|| self.inner.base_text.read(cx).text())
1357    }
1358
1359    #[cfg(any(test, feature = "test-support"))]
1360    pub fn recalculate_diff_sync(&mut self, buffer: text::BufferSnapshot, cx: &mut Context<Self>) {
1361        let language = self.base_text(cx).language().cloned();
1362        let base_text = self.base_text_string(cx).map(|s| s.as_str().into());
1363        let fut = self.update_diff(buffer.clone(), base_text, false, language, cx);
1364        let snapshot = cx.background_executor().block(fut);
1365        self.set_snapshot(snapshot, &buffer, false, cx);
1366    }
1367}
1368
1369impl DiffHunk {
1370    pub fn is_created_file(&self) -> bool {
1371        self.diff_base_byte_range == (0..0)
1372            && self.buffer_range.start.is_min()
1373            && self.buffer_range.end.is_max()
1374    }
1375
1376    pub fn status(&self) -> DiffHunkStatus {
1377        let kind = if self.buffer_range.start == self.buffer_range.end {
1378            DiffHunkStatusKind::Deleted
1379        } else if self.diff_base_byte_range.is_empty() {
1380            DiffHunkStatusKind::Added
1381        } else {
1382            DiffHunkStatusKind::Modified
1383        };
1384        DiffHunkStatus {
1385            kind,
1386            secondary: self.secondary_status,
1387        }
1388    }
1389}
1390
1391impl DiffHunkStatus {
1392    pub fn has_secondary_hunk(&self) -> bool {
1393        matches!(
1394            self.secondary,
1395            DiffHunkSecondaryStatus::HasSecondaryHunk
1396                | DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
1397                | DiffHunkSecondaryStatus::OverlapsWithSecondaryHunk
1398        )
1399    }
1400
1401    pub fn is_pending(&self) -> bool {
1402        matches!(
1403            self.secondary,
1404            DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
1405                | DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
1406        )
1407    }
1408
1409    pub fn is_deleted(&self) -> bool {
1410        self.kind == DiffHunkStatusKind::Deleted
1411    }
1412
1413    pub fn is_added(&self) -> bool {
1414        self.kind == DiffHunkStatusKind::Added
1415    }
1416
1417    pub fn is_modified(&self) -> bool {
1418        self.kind == DiffHunkStatusKind::Modified
1419    }
1420
1421    pub fn added(secondary: DiffHunkSecondaryStatus) -> Self {
1422        Self {
1423            kind: DiffHunkStatusKind::Added,
1424            secondary,
1425        }
1426    }
1427
1428    pub fn modified(secondary: DiffHunkSecondaryStatus) -> Self {
1429        Self {
1430            kind: DiffHunkStatusKind::Modified,
1431            secondary,
1432        }
1433    }
1434
1435    pub fn deleted(secondary: DiffHunkSecondaryStatus) -> Self {
1436        Self {
1437            kind: DiffHunkStatusKind::Deleted,
1438            secondary,
1439        }
1440    }
1441
1442    pub fn deleted_none() -> Self {
1443        Self {
1444            kind: DiffHunkStatusKind::Deleted,
1445            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1446        }
1447    }
1448
1449    pub fn added_none() -> Self {
1450        Self {
1451            kind: DiffHunkStatusKind::Added,
1452            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1453        }
1454    }
1455
1456    pub fn modified_none() -> Self {
1457        Self {
1458            kind: DiffHunkStatusKind::Modified,
1459            secondary: DiffHunkSecondaryStatus::NoSecondaryHunk,
1460        }
1461    }
1462}
1463
1464#[cfg(any(test, feature = "test-support"))]
1465#[track_caller]
1466pub fn assert_hunks<ExpectedText, HunkIter>(
1467    diff_hunks: HunkIter,
1468    buffer: &text::BufferSnapshot,
1469    diff_base: &str,
1470    // Line range, deleted, added, status
1471    expected_hunks: &[(Range<u32>, ExpectedText, ExpectedText, DiffHunkStatus)],
1472) where
1473    HunkIter: Iterator<Item = DiffHunk>,
1474    ExpectedText: AsRef<str>,
1475{
1476    let actual_hunks = diff_hunks
1477        .map(|hunk| {
1478            (
1479                hunk.range.clone(),
1480                &diff_base[hunk.diff_base_byte_range.clone()],
1481                buffer
1482                    .text_for_range(hunk.range.clone())
1483                    .collect::<String>(),
1484                hunk.status(),
1485            )
1486        })
1487        .collect::<Vec<_>>();
1488
1489    let expected_hunks: Vec<_> = expected_hunks
1490        .iter()
1491        .map(|(line_range, deleted_text, added_text, status)| {
1492            (
1493                Point::new(line_range.start, 0)..Point::new(line_range.end, 0),
1494                deleted_text.as_ref(),
1495                added_text.as_ref().to_string(),
1496                *status,
1497            )
1498        })
1499        .collect();
1500
1501    pretty_assertions::assert_eq!(actual_hunks, expected_hunks);
1502}
1503
1504#[cfg(test)]
1505mod tests {
1506    use std::fmt::Write as _;
1507
1508    use super::*;
1509    use gpui::TestAppContext;
1510    use pretty_assertions::{assert_eq, assert_ne};
1511    use rand::{Rng as _, rngs::StdRng};
1512    use text::{Buffer, BufferId, ReplicaId, Rope};
1513    use unindent::Unindent as _;
1514    use util::test::marked_text_ranges;
1515
1516    #[ctor::ctor]
1517    fn init_logger() {
1518        zlog::init_test();
1519    }
1520
1521    #[gpui::test]
1522    async fn test_buffer_diff_simple(cx: &mut gpui::TestAppContext) {
1523        let diff_base = "
1524            one
1525            two
1526            three
1527        "
1528        .unindent();
1529
1530        let buffer_text = "
1531            one
1532            HELLO
1533            three
1534        "
1535        .unindent();
1536
1537        let mut buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1538        let mut diff = BufferDiffSnapshot::new_sync(buffer.clone(), diff_base.clone(), cx);
1539        assert_hunks(
1540            diff.hunks_intersecting_range(
1541                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1542                &buffer,
1543            ),
1544            &buffer,
1545            &diff_base,
1546            &[(1..2, "two\n", "HELLO\n", DiffHunkStatus::modified_none())],
1547        );
1548
1549        buffer.edit([(0..0, "point five\n")]);
1550        diff = BufferDiffSnapshot::new_sync(buffer.clone(), diff_base.clone(), cx);
1551        assert_hunks(
1552            diff.hunks_intersecting_range(
1553                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1554                &buffer,
1555            ),
1556            &buffer,
1557            &diff_base,
1558            &[
1559                (0..1, "", "point five\n", DiffHunkStatus::added_none()),
1560                (2..3, "two\n", "HELLO\n", DiffHunkStatus::modified_none()),
1561            ],
1562        );
1563
1564        diff = cx.update(|cx| BufferDiff::new(&buffer, cx).snapshot(cx));
1565        assert_hunks::<&str, _>(
1566            diff.hunks_intersecting_range(
1567                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1568                &buffer,
1569            ),
1570            &buffer,
1571            &diff_base,
1572            &[],
1573        );
1574    }
1575
1576    #[gpui::test]
1577    async fn test_buffer_diff_with_secondary(cx: &mut gpui::TestAppContext) {
1578        let head_text = "
1579            zero
1580            one
1581            two
1582            three
1583            four
1584            five
1585            six
1586            seven
1587            eight
1588            nine
1589        "
1590        .unindent();
1591
1592        let index_text = "
1593            zero
1594            one
1595            TWO
1596            three
1597            FOUR
1598            five
1599            six
1600            seven
1601            eight
1602            NINE
1603        "
1604        .unindent();
1605
1606        let buffer_text = "
1607            zero
1608            one
1609            TWO
1610            three
1611            FOUR
1612            FIVE
1613            six
1614            SEVEN
1615            eight
1616            nine
1617        "
1618        .unindent();
1619
1620        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1621        let unstaged_diff = BufferDiffSnapshot::new_sync(buffer.clone(), index_text, cx);
1622        let mut uncommitted_diff =
1623            BufferDiffSnapshot::new_sync(buffer.clone(), head_text.clone(), cx);
1624        uncommitted_diff.secondary_diff = Some(Box::new(unstaged_diff));
1625
1626        let expected_hunks = vec![
1627            (2..3, "two\n", "TWO\n", DiffHunkStatus::modified_none()),
1628            (
1629                4..6,
1630                "four\nfive\n",
1631                "FOUR\nFIVE\n",
1632                DiffHunkStatus::modified(DiffHunkSecondaryStatus::OverlapsWithSecondaryHunk),
1633            ),
1634            (
1635                7..8,
1636                "seven\n",
1637                "SEVEN\n",
1638                DiffHunkStatus::modified(DiffHunkSecondaryStatus::HasSecondaryHunk),
1639            ),
1640        ];
1641
1642        assert_hunks(
1643            uncommitted_diff.hunks_intersecting_range(
1644                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1645                &buffer,
1646            ),
1647            &buffer,
1648            &head_text,
1649            &expected_hunks,
1650        );
1651    }
1652
1653    #[gpui::test]
1654    async fn test_buffer_diff_range(cx: &mut TestAppContext) {
1655        let diff_base = "
1656            one
1657            two
1658            three
1659            four
1660            five
1661            six
1662            seven
1663            eight
1664            nine
1665            ten
1666        "
1667        .unindent();
1668
1669        let buffer_text = "
1670            A
1671            one
1672            B
1673            two
1674            C
1675            three
1676            HELLO
1677            four
1678            five
1679            SIXTEEN
1680            seven
1681            eight
1682            WORLD
1683            nine
1684
1685            ten
1686
1687        "
1688        .unindent();
1689
1690        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1691        let diff = BufferDiffSnapshot::new_sync(buffer.snapshot(), diff_base.clone(), cx);
1692        assert_eq!(
1693            diff.hunks_intersecting_range(
1694                Anchor::min_max_range_for_buffer(buffer.remote_id()),
1695                &buffer
1696            )
1697            .count(),
1698            8
1699        );
1700
1701        assert_hunks(
1702            diff.hunks_intersecting_range(
1703                buffer.anchor_before(Point::new(7, 0))..buffer.anchor_before(Point::new(12, 0)),
1704                &buffer,
1705            ),
1706            &buffer,
1707            &diff_base,
1708            &[
1709                (6..7, "", "HELLO\n", DiffHunkStatus::added_none()),
1710                (9..10, "six\n", "SIXTEEN\n", DiffHunkStatus::modified_none()),
1711                (12..13, "", "WORLD\n", DiffHunkStatus::added_none()),
1712            ],
1713        );
1714    }
1715
1716    #[gpui::test]
1717    async fn test_stage_hunk(cx: &mut TestAppContext) {
1718        struct Example {
1719            name: &'static str,
1720            head_text: String,
1721            index_text: String,
1722            buffer_marked_text: String,
1723            final_index_text: String,
1724        }
1725
1726        let table = [
1727            Example {
1728                name: "uncommitted hunk straddles end of unstaged hunk",
1729                head_text: "
1730                    one
1731                    two
1732                    three
1733                    four
1734                    five
1735                "
1736                .unindent(),
1737                index_text: "
1738                    one
1739                    TWO_HUNDRED
1740                    three
1741                    FOUR_HUNDRED
1742                    five
1743                "
1744                .unindent(),
1745                buffer_marked_text: "
1746                    ZERO
1747                    one
1748                    two
1749                    «THREE_HUNDRED
1750                    FOUR_HUNDRED»
1751                    five
1752                    SIX
1753                "
1754                .unindent(),
1755                final_index_text: "
1756                    one
1757                    two
1758                    THREE_HUNDRED
1759                    FOUR_HUNDRED
1760                    five
1761                "
1762                .unindent(),
1763            },
1764            Example {
1765                name: "uncommitted hunk straddles start of unstaged hunk",
1766                head_text: "
1767                    one
1768                    two
1769                    three
1770                    four
1771                    five
1772                "
1773                .unindent(),
1774                index_text: "
1775                    one
1776                    TWO_HUNDRED
1777                    three
1778                    FOUR_HUNDRED
1779                    five
1780                "
1781                .unindent(),
1782                buffer_marked_text: "
1783                    ZERO
1784                    one
1785                    «TWO_HUNDRED
1786                    THREE_HUNDRED»
1787                    four
1788                    five
1789                    SIX
1790                "
1791                .unindent(),
1792                final_index_text: "
1793                    one
1794                    TWO_HUNDRED
1795                    THREE_HUNDRED
1796                    four
1797                    five
1798                "
1799                .unindent(),
1800            },
1801            Example {
1802                name: "uncommitted hunk strictly contains unstaged hunks",
1803                head_text: "
1804                    one
1805                    two
1806                    three
1807                    four
1808                    five
1809                    six
1810                    seven
1811                "
1812                .unindent(),
1813                index_text: "
1814                    one
1815                    TWO
1816                    THREE
1817                    FOUR
1818                    FIVE
1819                    SIX
1820                    seven
1821                "
1822                .unindent(),
1823                buffer_marked_text: "
1824                    one
1825                    TWO
1826                    «THREE_HUNDRED
1827                    FOUR
1828                    FIVE_HUNDRED»
1829                    SIX
1830                    seven
1831                "
1832                .unindent(),
1833                final_index_text: "
1834                    one
1835                    TWO
1836                    THREE_HUNDRED
1837                    FOUR
1838                    FIVE_HUNDRED
1839                    SIX
1840                    seven
1841                "
1842                .unindent(),
1843            },
1844            Example {
1845                name: "uncommitted deletion hunk",
1846                head_text: "
1847                    one
1848                    two
1849                    three
1850                    four
1851                    five
1852                "
1853                .unindent(),
1854                index_text: "
1855                    one
1856                    two
1857                    three
1858                    four
1859                    five
1860                "
1861                .unindent(),
1862                buffer_marked_text: "
1863                    one
1864                    ˇfive
1865                "
1866                .unindent(),
1867                final_index_text: "
1868                    one
1869                    five
1870                "
1871                .unindent(),
1872            },
1873            Example {
1874                name: "one unstaged hunk that contains two uncommitted hunks",
1875                head_text: "
1876                    one
1877                    two
1878
1879                    three
1880                    four
1881                "
1882                .unindent(),
1883                index_text: "
1884                    one
1885                    two
1886                    three
1887                    four
1888                "
1889                .unindent(),
1890                buffer_marked_text: "
1891                    «one
1892
1893                    three // modified
1894                    four»
1895                "
1896                .unindent(),
1897                final_index_text: "
1898                    one
1899
1900                    three // modified
1901                    four
1902                "
1903                .unindent(),
1904            },
1905            Example {
1906                name: "one uncommitted hunk that contains two unstaged hunks",
1907                head_text: "
1908                    one
1909                    two
1910                    three
1911                    four
1912                    five
1913                "
1914                .unindent(),
1915                index_text: "
1916                    ZERO
1917                    one
1918                    TWO
1919                    THREE
1920                    FOUR
1921                    five
1922                "
1923                .unindent(),
1924                buffer_marked_text: "
1925                    «one
1926                    TWO_HUNDRED
1927                    THREE
1928                    FOUR_HUNDRED
1929                    five»
1930                "
1931                .unindent(),
1932                final_index_text: "
1933                    ZERO
1934                    one
1935                    TWO_HUNDRED
1936                    THREE
1937                    FOUR_HUNDRED
1938                    five
1939                "
1940                .unindent(),
1941            },
1942        ];
1943
1944        for example in table {
1945            let (buffer_text, ranges) = marked_text_ranges(&example.buffer_marked_text, false);
1946            let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
1947            let hunk_range =
1948                buffer.anchor_before(ranges[0].start)..buffer.anchor_before(ranges[0].end);
1949
1950            let unstaged_diff =
1951                cx.new(|cx| BufferDiff::new_with_base_text(&example.index_text, &buffer, cx));
1952
1953            let uncommitted_diff = cx.new(|cx| {
1954                let mut diff = BufferDiff::new_with_base_text(&example.head_text, &buffer, cx);
1955                diff.set_secondary_diff(unstaged_diff);
1956                diff
1957            });
1958
1959            uncommitted_diff.update(cx, |diff, cx| {
1960                let hunks = diff
1961                    .snapshot(cx)
1962                    .hunks_intersecting_range(hunk_range.clone(), &buffer)
1963                    .collect::<Vec<_>>();
1964                for hunk in &hunks {
1965                    assert_ne!(
1966                        hunk.secondary_status,
1967                        DiffHunkSecondaryStatus::NoSecondaryHunk
1968                    )
1969                }
1970
1971                let new_index_text = diff
1972                    .stage_or_unstage_hunks(true, &hunks, &buffer, true, cx)
1973                    .unwrap()
1974                    .to_string();
1975
1976                let hunks = diff
1977                    .snapshot(cx)
1978                    .hunks_intersecting_range(hunk_range.clone(), &buffer)
1979                    .collect::<Vec<_>>();
1980                for hunk in &hunks {
1981                    assert_eq!(
1982                        hunk.secondary_status,
1983                        DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
1984                    )
1985                }
1986
1987                pretty_assertions::assert_eq!(
1988                    new_index_text,
1989                    example.final_index_text,
1990                    "example: {}",
1991                    example.name
1992                );
1993            });
1994        }
1995    }
1996
1997    #[gpui::test]
1998    async fn test_toggling_stage_and_unstage_same_hunk(cx: &mut TestAppContext) {
1999        let head_text = "
2000            one
2001            two
2002            three
2003        "
2004        .unindent();
2005        let index_text = head_text.clone();
2006        let buffer_text = "
2007            one
2008            three
2009        "
2010        .unindent();
2011
2012        let buffer = Buffer::new(
2013            ReplicaId::LOCAL,
2014            BufferId::new(1).unwrap(),
2015            buffer_text.clone(),
2016        );
2017        let unstaged_diff = cx.new(|cx| BufferDiff::new_with_base_text(&index_text, &buffer, cx));
2018        let uncommitted_diff = cx.new(|cx| {
2019            let mut diff = BufferDiff::new_with_base_text(&head_text, &buffer, cx);
2020            diff.set_secondary_diff(unstaged_diff.clone());
2021            diff
2022        });
2023
2024        uncommitted_diff.update(cx, |diff, cx| {
2025            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2026
2027            let new_index_text = diff
2028                .stage_or_unstage_hunks(true, std::slice::from_ref(&hunk), &buffer, true, cx)
2029                .unwrap()
2030                .to_string();
2031            assert_eq!(new_index_text, buffer_text);
2032
2033            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2034            assert_eq!(
2035                hunk.secondary_status,
2036                DiffHunkSecondaryStatus::SecondaryHunkRemovalPending
2037            );
2038
2039            let index_text = diff
2040                .stage_or_unstage_hunks(false, &[hunk], &buffer, true, cx)
2041                .unwrap()
2042                .to_string();
2043            assert_eq!(index_text, head_text);
2044
2045            let hunk = diff.snapshot(cx).hunks(&buffer).next().unwrap();
2046            // optimistically unstaged (fine, could also be HasSecondaryHunk)
2047            assert_eq!(
2048                hunk.secondary_status,
2049                DiffHunkSecondaryStatus::SecondaryHunkAdditionPending
2050            );
2051        });
2052    }
2053
2054    #[gpui::test]
2055    async fn test_buffer_diff_compare(cx: &mut TestAppContext) {
2056        let base_text = "
2057            zero
2058            one
2059            two
2060            three
2061            four
2062            five
2063            six
2064            seven
2065            eight
2066            nine
2067        "
2068        .unindent();
2069
2070        let buffer_text_1 = "
2071            one
2072            three
2073            four
2074            five
2075            SIX
2076            seven
2077            eight
2078            NINE
2079        "
2080        .unindent();
2081
2082        let mut buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text_1);
2083
2084        let empty_diff = cx.update(|cx| BufferDiff::new(&buffer, cx).snapshot(cx));
2085        let diff_1 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2086        // FIXME assert the other half of the range
2087        let (range, base_text_range) =
2088            compare_hunks(&diff_1.inner.hunks, &empty_diff.inner.hunks, &buffer);
2089        let range = range.unwrap();
2090        assert_eq!(range.to_point(&buffer), Point::new(0, 0)..Point::new(8, 0));
2091
2092        // Edit does not affect the diff.
2093        buffer.edit_via_marked_text(
2094            &"
2095                one
2096                three
2097                four
2098                five
2099                «SIX.5»
2100                seven
2101                eight
2102                NINE
2103            "
2104            .unindent(),
2105        );
2106        let diff_2 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2107        assert_eq!(
2108            (None, None),
2109            compare_hunks(&diff_2.inner.hunks, &diff_1.inner.hunks, &buffer)
2110        );
2111
2112        // Edit turns a deletion hunk into a modification.
2113        buffer.edit_via_marked_text(
2114            &"
2115                one
2116                «THREE»
2117                four
2118                five
2119                SIX.5
2120                seven
2121                eight
2122                NINE
2123            "
2124            .unindent(),
2125        );
2126        let diff_3 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2127        // FIXME assert the other range
2128        let (range, base_text_range) =
2129            compare_hunks(&diff_3.inner.hunks, &diff_2.inner.hunks, &buffer);
2130        let range = range.unwrap();
2131        assert_eq!(range.to_point(&buffer), Point::new(1, 0)..Point::new(2, 0));
2132
2133        // Edit turns a modification hunk into a deletion.
2134        buffer.edit_via_marked_text(
2135            &"
2136                one
2137                THREE
2138                four
2139                five«»
2140                seven
2141                eight
2142                NINE
2143            "
2144            .unindent(),
2145        );
2146        let diff_4 = BufferDiffSnapshot::new_sync(buffer.clone(), base_text.clone(), cx);
2147        let (range, base_text_range) =
2148            compare_hunks(&diff_4.inner.hunks, &diff_3.inner.hunks, &buffer);
2149        let range = range.unwrap();
2150        assert_eq!(range.to_point(&buffer), Point::new(3, 4)..Point::new(4, 0));
2151
2152        // Edit introduces a new insertion hunk.
2153        buffer.edit_via_marked_text(
2154            &"
2155                one
2156                THREE
2157                four«
2158                FOUR.5
2159                »five
2160                seven
2161                eight
2162                NINE
2163            "
2164            .unindent(),
2165        );
2166        let diff_5 = BufferDiffSnapshot::new_sync(buffer.snapshot(), base_text.clone(), cx);
2167        let (range, base_text_range) =
2168            compare_hunks(&diff_5.inner.hunks, &diff_4.inner.hunks, &buffer);
2169        let range = range.unwrap();
2170        assert_eq!(range.to_point(&buffer), Point::new(3, 0)..Point::new(4, 0));
2171
2172        // Edit removes a hunk.
2173        buffer.edit_via_marked_text(
2174            &"
2175                one
2176                THREE
2177                four
2178                FOUR.5
2179                five
2180                seven
2181                eight
2182                «nine»
2183            "
2184            .unindent(),
2185        );
2186        let diff_6 = BufferDiffSnapshot::new_sync(buffer.snapshot(), base_text, cx);
2187        let (range, base_text_range) =
2188            compare_hunks(&diff_6.inner.hunks, &diff_5.inner.hunks, &buffer);
2189        let range = range.unwrap();
2190        assert_eq!(range.to_point(&buffer), Point::new(7, 0)..Point::new(8, 0));
2191    }
2192
2193    #[gpui::test(iterations = 100)]
2194    async fn test_staging_and_unstaging_hunks(cx: &mut TestAppContext, mut rng: StdRng) {
2195        fn gen_line(rng: &mut StdRng) -> String {
2196            if rng.random_bool(0.2) {
2197                "\n".to_owned()
2198            } else {
2199                let c = rng.random_range('A'..='Z');
2200                format!("{c}{c}{c}\n")
2201            }
2202        }
2203
2204        fn gen_working_copy(rng: &mut StdRng, head: &str) -> String {
2205            let mut old_lines = {
2206                let mut old_lines = Vec::new();
2207                let old_lines_iter = head.lines();
2208                for line in old_lines_iter {
2209                    assert!(!line.ends_with("\n"));
2210                    old_lines.push(line.to_owned());
2211                }
2212                if old_lines.last().is_some_and(|line| line.is_empty()) {
2213                    old_lines.pop();
2214                }
2215                old_lines.into_iter()
2216            };
2217            let mut result = String::new();
2218            let unchanged_count = rng.random_range(0..=old_lines.len());
2219            result +=
2220                &old_lines
2221                    .by_ref()
2222                    .take(unchanged_count)
2223                    .fold(String::new(), |mut s, line| {
2224                        writeln!(&mut s, "{line}").unwrap();
2225                        s
2226                    });
2227            while old_lines.len() > 0 {
2228                let deleted_count = rng.random_range(0..=old_lines.len());
2229                let _advance = old_lines
2230                    .by_ref()
2231                    .take(deleted_count)
2232                    .map(|line| line.len() + 1)
2233                    .sum::<usize>();
2234                let minimum_added = if deleted_count == 0 { 1 } else { 0 };
2235                let added_count = rng.random_range(minimum_added..=5);
2236                let addition = (0..added_count).map(|_| gen_line(rng)).collect::<String>();
2237                result += &addition;
2238
2239                if old_lines.len() > 0 {
2240                    let blank_lines = old_lines.clone().take_while(|line| line.is_empty()).count();
2241                    if blank_lines == old_lines.len() {
2242                        break;
2243                    };
2244                    let unchanged_count =
2245                        rng.random_range((blank_lines + 1).max(1)..=old_lines.len());
2246                    result += &old_lines.by_ref().take(unchanged_count).fold(
2247                        String::new(),
2248                        |mut s, line| {
2249                            writeln!(&mut s, "{line}").unwrap();
2250                            s
2251                        },
2252                    );
2253                }
2254            }
2255            result
2256        }
2257
2258        fn uncommitted_diff(
2259            working_copy: &language::BufferSnapshot,
2260            index_text: &Rope,
2261            head_text: String,
2262            cx: &mut TestAppContext,
2263        ) -> Entity<BufferDiff> {
2264            let secondary = cx.new(|cx| {
2265                BufferDiff::new_with_base_text(&index_text.to_string(), &working_copy.text, cx)
2266            });
2267            cx.new(|cx| {
2268                let mut diff = BufferDiff::new_with_base_text(&head_text, &working_copy.text, cx);
2269                diff.secondary_diff = Some(secondary);
2270                diff
2271            })
2272        }
2273
2274        let operations = std::env::var("OPERATIONS")
2275            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
2276            .unwrap_or(10);
2277
2278        let rng = &mut rng;
2279        let head_text = ('a'..='z').fold(String::new(), |mut s, c| {
2280            writeln!(&mut s, "{c}{c}{c}").unwrap();
2281            s
2282        });
2283        let working_copy = gen_working_copy(rng, &head_text);
2284        let working_copy = cx.new(|cx| {
2285            language::Buffer::local_normalized(
2286                Rope::from(working_copy.as_str()),
2287                text::LineEnding::default(),
2288                cx,
2289            )
2290        });
2291        let working_copy = working_copy.read_with(cx, |working_copy, _| working_copy.snapshot());
2292        let mut index_text = if rng.random() {
2293            Rope::from(head_text.as_str())
2294        } else {
2295            working_copy.as_rope().clone()
2296        };
2297
2298        let mut diff = uncommitted_diff(&working_copy, &index_text, head_text.clone(), cx);
2299        let mut hunks = diff.update(cx, |diff, cx| {
2300            diff.snapshot(cx)
2301                .hunks_intersecting_range(
2302                    Anchor::min_max_range_for_buffer(diff.buffer_id),
2303                    &working_copy,
2304                )
2305                .collect::<Vec<_>>()
2306        });
2307        if hunks.is_empty() {
2308            return;
2309        }
2310
2311        for _ in 0..operations {
2312            let i = rng.random_range(0..hunks.len());
2313            let hunk = &mut hunks[i];
2314            let hunk_to_change = hunk.clone();
2315            let stage = match hunk.secondary_status {
2316                DiffHunkSecondaryStatus::HasSecondaryHunk => {
2317                    hunk.secondary_status = DiffHunkSecondaryStatus::NoSecondaryHunk;
2318                    true
2319                }
2320                DiffHunkSecondaryStatus::NoSecondaryHunk => {
2321                    hunk.secondary_status = DiffHunkSecondaryStatus::HasSecondaryHunk;
2322                    false
2323                }
2324                _ => unreachable!(),
2325            };
2326
2327            index_text = diff.update(cx, |diff, cx| {
2328                diff.stage_or_unstage_hunks(stage, &[hunk_to_change], &working_copy, true, cx)
2329                    .unwrap()
2330            });
2331
2332            diff = uncommitted_diff(&working_copy, &index_text, head_text.clone(), cx);
2333            let found_hunks = diff.update(cx, |diff, cx| {
2334                diff.snapshot(cx)
2335                    .hunks_intersecting_range(
2336                        Anchor::min_max_range_for_buffer(diff.buffer_id),
2337                        &working_copy,
2338                    )
2339                    .collect::<Vec<_>>()
2340            });
2341            assert_eq!(hunks.len(), found_hunks.len());
2342
2343            for (expected_hunk, found_hunk) in hunks.iter().zip(&found_hunks) {
2344                assert_eq!(
2345                    expected_hunk.buffer_range.to_point(&working_copy),
2346                    found_hunk.buffer_range.to_point(&working_copy)
2347                );
2348                assert_eq!(
2349                    expected_hunk.diff_base_byte_range,
2350                    found_hunk.diff_base_byte_range
2351                );
2352                assert_eq!(expected_hunk.secondary_status, found_hunk.secondary_status);
2353            }
2354            hunks = found_hunks;
2355        }
2356    }
2357
2358    #[gpui::test]
2359    async fn test_row_to_base_text_row(cx: &mut TestAppContext) {
2360        let base_text = "
2361            zero
2362            one
2363            two
2364            three
2365            four
2366            five
2367            six
2368            seven
2369            eight
2370        "
2371        .unindent();
2372        let buffer_text = "
2373            zero
2374            ONE
2375            two
2376            NINE
2377            five
2378            seven
2379        "
2380        .unindent();
2381
2382        //   zero
2383        // - one
2384        // + ONE
2385        //   two
2386        // - three
2387        // - four
2388        // + NINE
2389        //   five
2390        // - six
2391        //   seven
2392        // + eight
2393
2394        let buffer = Buffer::new(ReplicaId::LOCAL, BufferId::new(1).unwrap(), buffer_text);
2395        let buffer_snapshot = buffer.snapshot();
2396        let diff = BufferDiffSnapshot::new_sync(buffer_snapshot.clone(), base_text, cx);
2397        let expected_results = [
2398            // don't format me
2399            (0, 0),
2400            (1, 2),
2401            (2, 2),
2402            (3, 5),
2403            (4, 5),
2404            (5, 7),
2405            (6, 9),
2406        ];
2407        for (buffer_row, expected) in expected_results {
2408            assert_eq!(
2409                diff.row_to_base_text_row(buffer_row, &buffer_snapshot),
2410                expected,
2411                "{buffer_row}"
2412            );
2413        }
2414    }
2415}