1use super::TextHighlights;
   2use crate::{
   3    multi_buffer::MultiBufferRows, Anchor, AnchorRangeExt, MultiBufferChunks, MultiBufferSnapshot,
   4    ToOffset,
   5};
   6use collections::BTreeMap;
   7use gpui::fonts::HighlightStyle;
   8use language::{Chunk, Edit, TextSummary};
   9use parking_lot::Mutex;
  10use rope::point::Point;
  11use std::{
  12    any::TypeId,
  13    cmp::{self, Ordering},
  14    iter::{self, Peekable},
  15    ops::{Range, Sub},
  16    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  17    vec,
  18};
  19use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  20
  21#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  22pub struct FoldPoint(pub Point);
  23
  24impl FoldPoint {
  25    pub fn new(row: u32, column: u32) -> Self {
  26        Self(Point::new(row, column))
  27    }
  28
  29    pub fn row(self) -> u32 {
  30        self.0.row
  31    }
  32
  33    pub fn column(self) -> u32 {
  34        self.0.column
  35    }
  36
  37    pub fn row_mut(&mut self) -> &mut u32 {
  38        &mut self.0.row
  39    }
  40
  41    pub fn column_mut(&mut self) -> &mut u32 {
  42        &mut self.0.column
  43    }
  44
  45    pub fn to_buffer_point(self, snapshot: &FoldSnapshot) -> Point {
  46        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  47        cursor.seek(&self, Bias::Right, &());
  48        let overshoot = self.0 - cursor.start().0 .0;
  49        cursor.start().1 + overshoot
  50    }
  51
  52    pub fn to_buffer_offset(self, snapshot: &FoldSnapshot) -> usize {
  53        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  54        cursor.seek(&self, Bias::Right, &());
  55        let overshoot = self.0 - cursor.start().0 .0;
  56        snapshot
  57            .buffer_snapshot
  58            .point_to_offset(cursor.start().1 + overshoot)
  59    }
  60
  61    pub fn to_offset(self, snapshot: &FoldSnapshot) -> FoldOffset {
  62        let mut cursor = snapshot
  63            .transforms
  64            .cursor::<(FoldPoint, TransformSummary)>();
  65        cursor.seek(&self, Bias::Right, &());
  66        let overshoot = self.0 - cursor.start().1.output.lines;
  67        let mut offset = cursor.start().1.output.len;
  68        if !overshoot.is_zero() {
  69            let transform = cursor.item().expect("display point out of range");
  70            assert!(transform.output_text.is_none());
  71            let end_buffer_offset = snapshot
  72                .buffer_snapshot
  73                .point_to_offset(cursor.start().1.input.lines + overshoot);
  74            offset += end_buffer_offset - cursor.start().1.input.len;
  75        }
  76        FoldOffset(offset)
  77    }
  78}
  79
  80impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
  81    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
  82        self.0 += &summary.output.lines;
  83    }
  84}
  85
  86pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  87
  88impl<'a> FoldMapWriter<'a> {
  89    pub fn fold<T: ToOffset>(
  90        &mut self,
  91        ranges: impl IntoIterator<Item = Range<T>>,
  92    ) -> (FoldSnapshot, Vec<FoldEdit>) {
  93        let mut edits = Vec::new();
  94        let mut folds = Vec::new();
  95        let buffer = self.0.buffer.lock().clone();
  96        for range in ranges.into_iter() {
  97            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
  98
  99            // Ignore any empty ranges.
 100            if range.start == range.end {
 101                continue;
 102            }
 103
 104            // For now, ignore any ranges that span an excerpt boundary.
 105            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 106            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 107                continue;
 108            }
 109
 110            folds.push(fold);
 111            edits.push(text::Edit {
 112                old: range.clone(),
 113                new: range,
 114            });
 115        }
 116
 117        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 118
 119        self.0.folds = {
 120            let mut new_tree = SumTree::new();
 121            let mut cursor = self.0.folds.cursor::<Fold>();
 122            for fold in folds {
 123                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 124                new_tree.push(fold, &buffer);
 125            }
 126            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 127            new_tree
 128        };
 129
 130        consolidate_buffer_edits(&mut edits);
 131        let edits = self.0.sync(buffer.clone(), edits);
 132        let snapshot = FoldSnapshot {
 133            transforms: self.0.transforms.lock().clone(),
 134            folds: self.0.folds.clone(),
 135            buffer_snapshot: buffer,
 136            version: self.0.version.load(SeqCst),
 137        };
 138        (snapshot, edits)
 139    }
 140
 141    pub fn unfold<T: ToOffset>(
 142        &mut self,
 143        ranges: impl IntoIterator<Item = Range<T>>,
 144        inclusive: bool,
 145    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 146        let mut edits = Vec::new();
 147        let mut fold_ixs_to_delete = Vec::new();
 148        let buffer = self.0.buffer.lock().clone();
 149        for range in ranges.into_iter() {
 150            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 151            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, inclusive);
 152            while let Some(fold) = folds_cursor.item() {
 153                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 154                if offset_range.end > offset_range.start {
 155                    edits.push(text::Edit {
 156                        old: offset_range.clone(),
 157                        new: offset_range,
 158                    });
 159                }
 160                fold_ixs_to_delete.push(*folds_cursor.start());
 161                folds_cursor.next(&buffer);
 162            }
 163        }
 164
 165        fold_ixs_to_delete.sort_unstable();
 166        fold_ixs_to_delete.dedup();
 167
 168        self.0.folds = {
 169            let mut cursor = self.0.folds.cursor::<usize>();
 170            let mut folds = SumTree::new();
 171            for fold_ix in fold_ixs_to_delete {
 172                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 173                cursor.next(&buffer);
 174            }
 175            folds.push_tree(cursor.suffix(&buffer), &buffer);
 176            folds
 177        };
 178
 179        consolidate_buffer_edits(&mut edits);
 180        let edits = self.0.sync(buffer.clone(), edits);
 181        let snapshot = FoldSnapshot {
 182            transforms: self.0.transforms.lock().clone(),
 183            folds: self.0.folds.clone(),
 184            buffer_snapshot: buffer,
 185            version: self.0.version.load(SeqCst),
 186        };
 187        (snapshot, edits)
 188    }
 189}
 190
 191pub struct FoldMap {
 192    buffer: Mutex<MultiBufferSnapshot>,
 193    transforms: Mutex<SumTree<Transform>>,
 194    folds: SumTree<Fold>,
 195    version: AtomicUsize,
 196}
 197
 198impl FoldMap {
 199    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 200        let this = Self {
 201            buffer: Mutex::new(buffer.clone()),
 202            folds: Default::default(),
 203            transforms: Mutex::new(SumTree::from_item(
 204                Transform {
 205                    summary: TransformSummary {
 206                        input: buffer.text_summary(),
 207                        output: buffer.text_summary(),
 208                    },
 209                    output_text: None,
 210                },
 211                &(),
 212            )),
 213            version: Default::default(),
 214        };
 215
 216        let snapshot = FoldSnapshot {
 217            transforms: this.transforms.lock().clone(),
 218            folds: this.folds.clone(),
 219            buffer_snapshot: this.buffer.lock().clone(),
 220            version: this.version.load(SeqCst),
 221        };
 222        (this, snapshot)
 223    }
 224
 225    pub fn read(
 226        &self,
 227        buffer: MultiBufferSnapshot,
 228        edits: Vec<Edit<usize>>,
 229    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 230        let edits = self.sync(buffer, edits);
 231        self.check_invariants();
 232        let snapshot = FoldSnapshot {
 233            transforms: self.transforms.lock().clone(),
 234            folds: self.folds.clone(),
 235            buffer_snapshot: self.buffer.lock().clone(),
 236            version: self.version.load(SeqCst),
 237        };
 238        (snapshot, edits)
 239    }
 240
 241    pub fn write(
 242        &mut self,
 243        buffer: MultiBufferSnapshot,
 244        edits: Vec<Edit<usize>>,
 245    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 246        let (snapshot, edits) = self.read(buffer, edits);
 247        (FoldMapWriter(self), snapshot, edits)
 248    }
 249
 250    fn check_invariants(&self) {
 251        if cfg!(test) {
 252            assert_eq!(
 253                self.transforms.lock().summary().input.len,
 254                self.buffer.lock().len(),
 255                "transform tree does not match buffer's length"
 256            );
 257
 258            let mut folds = self.folds.iter().peekable();
 259            while let Some(fold) = folds.next() {
 260                if let Some(next_fold) = folds.peek() {
 261                    let comparison = fold.0.cmp(&next_fold.0, &self.buffer.lock());
 262                    assert!(comparison.is_le());
 263                }
 264            }
 265        }
 266    }
 267
 268    fn sync(
 269        &self,
 270        new_buffer: MultiBufferSnapshot,
 271        buffer_edits: Vec<text::Edit<usize>>,
 272    ) -> Vec<FoldEdit> {
 273        if buffer_edits.is_empty() {
 274            let mut buffer = self.buffer.lock();
 275            if buffer.edit_count() != new_buffer.edit_count()
 276                || buffer.parse_count() != new_buffer.parse_count()
 277                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 278                || buffer.git_diff_update_count() != new_buffer.git_diff_update_count()
 279                || buffer.trailing_excerpt_update_count()
 280                    != new_buffer.trailing_excerpt_update_count()
 281            {
 282                self.version.fetch_add(1, SeqCst);
 283            }
 284            *buffer = new_buffer;
 285            Vec::new()
 286        } else {
 287            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 288
 289            let mut new_transforms = SumTree::new();
 290            let mut transforms = self.transforms.lock();
 291            let mut cursor = transforms.cursor::<usize>();
 292            cursor.seek(&0, Bias::Right, &());
 293
 294            while let Some(mut edit) = buffer_edits_iter.next() {
 295                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 296                edit.new.start -= edit.old.start - cursor.start();
 297                edit.old.start = *cursor.start();
 298
 299                cursor.seek(&edit.old.end, Bias::Right, &());
 300                cursor.next(&());
 301
 302                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 303                loop {
 304                    edit.old.end = *cursor.start();
 305
 306                    if let Some(next_edit) = buffer_edits_iter.peek() {
 307                        if next_edit.old.start > edit.old.end {
 308                            break;
 309                        }
 310
 311                        let next_edit = buffer_edits_iter.next().unwrap();
 312                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 313
 314                        if next_edit.old.end >= edit.old.end {
 315                            edit.old.end = next_edit.old.end;
 316                            cursor.seek(&edit.old.end, Bias::Right, &());
 317                            cursor.next(&());
 318                        }
 319                    } else {
 320                        break;
 321                    }
 322                }
 323
 324                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 325
 326                let anchor = new_buffer.anchor_before(edit.new.start);
 327                let mut folds_cursor = self.folds.cursor::<Fold>();
 328                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 329
 330                let mut folds = iter::from_fn({
 331                    let buffer = &new_buffer;
 332                    move || {
 333                        let item = folds_cursor
 334                            .item()
 335                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 336                        folds_cursor.next(buffer);
 337                        item
 338                    }
 339                })
 340                .peekable();
 341
 342                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 343                    let mut fold = folds.next().unwrap();
 344                    let sum = new_transforms.summary();
 345
 346                    assert!(fold.start >= sum.input.len);
 347
 348                    while folds
 349                        .peek()
 350                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 351                    {
 352                        let next_fold = folds.next().unwrap();
 353                        if next_fold.end > fold.end {
 354                            fold.end = next_fold.end;
 355                        }
 356                    }
 357
 358                    if fold.start > sum.input.len {
 359                        let text_summary = new_buffer
 360                            .text_summary_for_range::<TextSummary, _>(sum.input.len..fold.start);
 361                        new_transforms.push(
 362                            Transform {
 363                                summary: TransformSummary {
 364                                    output: text_summary.clone(),
 365                                    input: text_summary,
 366                                },
 367                                output_text: None,
 368                            },
 369                            &(),
 370                        );
 371                    }
 372
 373                    if fold.end > fold.start {
 374                        let output_text = "…";
 375                        new_transforms.push(
 376                            Transform {
 377                                summary: TransformSummary {
 378                                    output: TextSummary::from(output_text),
 379                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 380                                },
 381                                output_text: Some(output_text),
 382                            },
 383                            &(),
 384                        );
 385                    }
 386                }
 387
 388                let sum = new_transforms.summary();
 389                if sum.input.len < edit.new.end {
 390                    let text_summary = new_buffer
 391                        .text_summary_for_range::<TextSummary, _>(sum.input.len..edit.new.end);
 392                    new_transforms.push(
 393                        Transform {
 394                            summary: TransformSummary {
 395                                output: text_summary.clone(),
 396                                input: text_summary,
 397                            },
 398                            output_text: None,
 399                        },
 400                        &(),
 401                    );
 402                }
 403            }
 404
 405            new_transforms.push_tree(cursor.suffix(&()), &());
 406            if new_transforms.is_empty() {
 407                let text_summary = new_buffer.text_summary();
 408                new_transforms.push(
 409                    Transform {
 410                        summary: TransformSummary {
 411                            output: text_summary.clone(),
 412                            input: text_summary,
 413                        },
 414                        output_text: None,
 415                    },
 416                    &(),
 417                );
 418            }
 419
 420            drop(cursor);
 421
 422            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 423            {
 424                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 425                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 426
 427                for mut edit in buffer_edits {
 428                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 429                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 430                        edit.old.start = old_transforms.start().0;
 431                    }
 432                    let old_start =
 433                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 434
 435                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 436                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 437                        old_transforms.next(&());
 438                        edit.old.end = old_transforms.start().0;
 439                    }
 440                    let old_end =
 441                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 442
 443                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 444                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 445                        edit.new.start = new_transforms.start().0;
 446                    }
 447                    let new_start =
 448                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 449
 450                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 451                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 452                        new_transforms.next(&());
 453                        edit.new.end = new_transforms.start().0;
 454                    }
 455                    let new_end =
 456                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 457
 458                    fold_edits.push(FoldEdit {
 459                        old: FoldOffset(old_start)..FoldOffset(old_end),
 460                        new: FoldOffset(new_start)..FoldOffset(new_end),
 461                    });
 462                }
 463
 464                consolidate_fold_edits(&mut fold_edits);
 465            }
 466
 467            *transforms = new_transforms;
 468            *self.buffer.lock() = new_buffer;
 469            self.version.fetch_add(1, SeqCst);
 470            fold_edits
 471        }
 472    }
 473}
 474
 475#[derive(Clone)]
 476pub struct FoldSnapshot {
 477    transforms: SumTree<Transform>,
 478    folds: SumTree<Fold>,
 479    buffer_snapshot: MultiBufferSnapshot,
 480    pub version: usize,
 481}
 482
 483impl FoldSnapshot {
 484    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 485        &self.buffer_snapshot
 486    }
 487
 488    #[cfg(test)]
 489    pub fn text(&self) -> String {
 490        self.chunks(FoldOffset(0)..self.len(), false, None)
 491            .map(|c| c.text)
 492            .collect()
 493    }
 494
 495    #[cfg(test)]
 496    pub fn fold_count(&self) -> usize {
 497        self.folds.items(&self.buffer_snapshot).len()
 498    }
 499
 500    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 501        let mut summary = TextSummary::default();
 502
 503        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 504        cursor.seek(&range.start, Bias::Right, &());
 505        if let Some(transform) = cursor.item() {
 506            let start_in_transform = range.start.0 - cursor.start().0 .0;
 507            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 508            if let Some(output_text) = transform.output_text {
 509                summary = TextSummary::from(
 510                    &output_text
 511                        [start_in_transform.column as usize..end_in_transform.column as usize],
 512                );
 513            } else {
 514                let buffer_start = cursor.start().1 + start_in_transform;
 515                let buffer_end = cursor.start().1 + end_in_transform;
 516                summary = self
 517                    .buffer_snapshot
 518                    .text_summary_for_range(buffer_start..buffer_end);
 519            }
 520        }
 521
 522        if range.end > cursor.end(&()).0 {
 523            cursor.next(&());
 524            summary += &cursor
 525                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 526                .output;
 527            if let Some(transform) = cursor.item() {
 528                let end_in_transform = range.end.0 - cursor.start().0 .0;
 529                if let Some(output_text) = transform.output_text {
 530                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 531                } else {
 532                    let buffer_start = cursor.start().1;
 533                    let buffer_end = cursor.start().1 + end_in_transform;
 534                    summary += self
 535                        .buffer_snapshot
 536                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 537                }
 538            }
 539        }
 540
 541        summary
 542    }
 543
 544    pub fn to_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
 545        let mut cursor = self.transforms.cursor::<(Point, FoldPoint)>();
 546        cursor.seek(&point, Bias::Right, &());
 547        if cursor.item().map_or(false, |t| t.is_fold()) {
 548            if bias == Bias::Left || point == cursor.start().0 {
 549                cursor.start().1
 550            } else {
 551                cursor.end(&()).1
 552            }
 553        } else {
 554            let overshoot = point - cursor.start().0;
 555            FoldPoint(cmp::min(
 556                cursor.start().1 .0 + overshoot,
 557                cursor.end(&()).1 .0,
 558            ))
 559        }
 560    }
 561
 562    pub fn len(&self) -> FoldOffset {
 563        FoldOffset(self.transforms.summary().output.len)
 564    }
 565
 566    pub fn line_len(&self, row: u32) -> u32 {
 567        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 568        let line_end = if row >= self.max_point().row() {
 569            self.len().0
 570        } else {
 571            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 572        };
 573        (line_end - line_start) as u32
 574    }
 575
 576    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 577        if start_row > self.transforms.summary().output.lines.row {
 578            panic!("invalid display row {}", start_row);
 579        }
 580
 581        let fold_point = FoldPoint::new(start_row, 0);
 582        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 583        cursor.seek(&fold_point, Bias::Left, &());
 584
 585        let overshoot = fold_point.0 - cursor.start().0 .0;
 586        let buffer_point = cursor.start().1 + overshoot;
 587        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 588
 589        FoldBufferRows {
 590            fold_point,
 591            input_buffer_rows,
 592            cursor,
 593        }
 594    }
 595
 596    pub fn max_point(&self) -> FoldPoint {
 597        FoldPoint(self.transforms.summary().output.lines)
 598    }
 599
 600    #[cfg(test)]
 601    pub fn longest_row(&self) -> u32 {
 602        self.transforms.summary().output.longest_row
 603    }
 604
 605    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Range<Anchor>>
 606    where
 607        T: ToOffset,
 608    {
 609        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 610        iter::from_fn(move || {
 611            let item = folds.item().map(|f| &f.0);
 612            folds.next(&self.buffer_snapshot);
 613            item
 614        })
 615    }
 616
 617    pub fn intersects_fold<T>(&self, offset: T) -> bool
 618    where
 619        T: ToOffset,
 620    {
 621        let offset = offset.to_offset(&self.buffer_snapshot);
 622        let mut cursor = self.transforms.cursor::<usize>();
 623        cursor.seek(&offset, Bias::Right, &());
 624        cursor.item().map_or(false, |t| t.output_text.is_some())
 625    }
 626
 627    pub fn is_line_folded(&self, output_row: u32) -> bool {
 628        let mut cursor = self.transforms.cursor::<FoldPoint>();
 629        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 630        while let Some(transform) = cursor.item() {
 631            if transform.output_text.is_some() {
 632                return true;
 633            }
 634            if cursor.end(&()).row() == output_row {
 635                cursor.next(&())
 636            } else {
 637                break;
 638            }
 639        }
 640        false
 641    }
 642
 643    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 644        let start = start.to_offset(self);
 645        self.chunks(start..self.len(), false, None)
 646            .flat_map(|chunk| chunk.text.chars())
 647    }
 648
 649    pub fn chunks<'a>(
 650        &'a self,
 651        range: Range<FoldOffset>,
 652        language_aware: bool,
 653        text_highlights: Option<&'a TextHighlights>,
 654    ) -> FoldChunks<'a> {
 655        let mut highlight_endpoints = Vec::new();
 656        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 657
 658        let buffer_end = {
 659            transform_cursor.seek(&range.end, Bias::Right, &());
 660            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 661            transform_cursor.start().1 + overshoot
 662        };
 663
 664        let buffer_start = {
 665            transform_cursor.seek(&range.start, Bias::Right, &());
 666            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 667            transform_cursor.start().1 + overshoot
 668        };
 669
 670        if let Some(text_highlights) = text_highlights {
 671            if !text_highlights.is_empty() {
 672                while transform_cursor.start().0 < range.end {
 673                    if !transform_cursor.item().unwrap().is_fold() {
 674                        let transform_start = self
 675                            .buffer_snapshot
 676                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 677
 678                        let transform_end = {
 679                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 680                            self.buffer_snapshot.anchor_before(cmp::min(
 681                                transform_cursor.end(&()).1,
 682                                transform_cursor.start().1 + overshoot,
 683                            ))
 684                        };
 685
 686                        for (tag, highlights) in text_highlights.iter() {
 687                            let style = highlights.0;
 688                            let ranges = &highlights.1;
 689
 690                            let start_ix = match ranges.binary_search_by(|probe| {
 691                                let cmp = probe.end.cmp(&transform_start, self.buffer_snapshot());
 692                                if cmp.is_gt() {
 693                                    Ordering::Greater
 694                                } else {
 695                                    Ordering::Less
 696                                }
 697                            }) {
 698                                Ok(i) | Err(i) => i,
 699                            };
 700                            for range in &ranges[start_ix..] {
 701                                if range
 702                                    .start
 703                                    .cmp(&transform_end, &self.buffer_snapshot)
 704                                    .is_ge()
 705                                {
 706                                    break;
 707                                }
 708
 709                                highlight_endpoints.push(HighlightEndpoint {
 710                                    offset: range.start.to_offset(&self.buffer_snapshot),
 711                                    is_start: true,
 712                                    tag: *tag,
 713                                    style,
 714                                });
 715                                highlight_endpoints.push(HighlightEndpoint {
 716                                    offset: range.end.to_offset(&self.buffer_snapshot),
 717                                    is_start: false,
 718                                    tag: *tag,
 719                                    style,
 720                                });
 721                            }
 722                        }
 723                    }
 724
 725                    transform_cursor.next(&());
 726                }
 727                highlight_endpoints.sort();
 728                transform_cursor.seek(&range.start, Bias::Right, &());
 729            }
 730        }
 731
 732        FoldChunks {
 733            transform_cursor,
 734            buffer_chunks: self
 735                .buffer_snapshot
 736                .chunks(buffer_start..buffer_end, language_aware),
 737            buffer_chunk: None,
 738            buffer_offset: buffer_start,
 739            output_offset: range.start.0,
 740            max_output_offset: range.end.0,
 741            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 742            active_highlights: Default::default(),
 743        }
 744    }
 745
 746    #[cfg(test)]
 747    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 748        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 749        cursor.seek(&offset, Bias::Right, &());
 750        if let Some(transform) = cursor.item() {
 751            let transform_start = cursor.start().0 .0;
 752            if transform.output_text.is_some() {
 753                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 754                    FoldOffset(transform_start)
 755                } else {
 756                    FoldOffset(cursor.end(&()).0 .0)
 757                }
 758            } else {
 759                let overshoot = offset.0 - transform_start;
 760                let buffer_offset = cursor.start().1 + overshoot;
 761                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 762                FoldOffset(
 763                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 764                        as usize,
 765                )
 766            }
 767        } else {
 768            FoldOffset(self.transforms.summary().output.len)
 769        }
 770    }
 771
 772    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 773        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 774        cursor.seek(&point, Bias::Right, &());
 775        if let Some(transform) = cursor.item() {
 776            let transform_start = cursor.start().0 .0;
 777            if transform.output_text.is_some() {
 778                if point.0 == transform_start || matches!(bias, Bias::Left) {
 779                    FoldPoint(transform_start)
 780                } else {
 781                    FoldPoint(cursor.end(&()).0 .0)
 782                }
 783            } else {
 784                let overshoot = point.0 - transform_start;
 785                let buffer_position = cursor.start().1 + overshoot;
 786                let clipped_buffer_position =
 787                    self.buffer_snapshot.clip_point(buffer_position, bias);
 788                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 789            }
 790        } else {
 791            FoldPoint(self.transforms.summary().output.lines)
 792        }
 793    }
 794}
 795
 796fn intersecting_folds<'a, T>(
 797    buffer: &'a MultiBufferSnapshot,
 798    folds: &'a SumTree<Fold>,
 799    range: Range<T>,
 800    inclusive: bool,
 801) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 802where
 803    T: ToOffset,
 804{
 805    let start = buffer.anchor_before(range.start.to_offset(buffer));
 806    let end = buffer.anchor_after(range.end.to_offset(buffer));
 807    let mut cursor = folds.filter::<_, usize>(move |summary| {
 808        let start_cmp = start.cmp(&summary.max_end, buffer);
 809        let end_cmp = end.cmp(&summary.min_start, buffer);
 810
 811        if inclusive {
 812            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 813        } else {
 814            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 815        }
 816    });
 817    cursor.next(buffer);
 818    cursor
 819}
 820
 821fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 822    edits.sort_unstable_by(|a, b| {
 823        a.old
 824            .start
 825            .cmp(&b.old.start)
 826            .then_with(|| b.old.end.cmp(&a.old.end))
 827    });
 828
 829    let mut i = 1;
 830    while i < edits.len() {
 831        let edit = edits[i].clone();
 832        let prev_edit = &mut edits[i - 1];
 833        if prev_edit.old.end >= edit.old.start {
 834            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 835            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 836            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 837            edits.remove(i);
 838            continue;
 839        }
 840        i += 1;
 841    }
 842}
 843
 844fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 845    edits.sort_unstable_by(|a, b| {
 846        a.old
 847            .start
 848            .cmp(&b.old.start)
 849            .then_with(|| b.old.end.cmp(&a.old.end))
 850    });
 851
 852    let mut i = 1;
 853    while i < edits.len() {
 854        let edit = edits[i].clone();
 855        let prev_edit = &mut edits[i - 1];
 856        if prev_edit.old.end >= edit.old.start {
 857            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 858            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 859            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 860            edits.remove(i);
 861            continue;
 862        }
 863        i += 1;
 864    }
 865}
 866
 867#[derive(Clone, Debug, Default, Eq, PartialEq)]
 868struct Transform {
 869    summary: TransformSummary,
 870    output_text: Option<&'static str>,
 871}
 872
 873impl Transform {
 874    fn is_fold(&self) -> bool {
 875        self.output_text.is_some()
 876    }
 877}
 878
 879#[derive(Clone, Debug, Default, Eq, PartialEq)]
 880struct TransformSummary {
 881    output: TextSummary,
 882    input: TextSummary,
 883}
 884
 885impl sum_tree::Item for Transform {
 886    type Summary = TransformSummary;
 887
 888    fn summary(&self) -> Self::Summary {
 889        self.summary.clone()
 890    }
 891}
 892
 893impl sum_tree::Summary for TransformSummary {
 894    type Context = ();
 895
 896    fn add_summary(&mut self, other: &Self, _: &()) {
 897        self.input += &other.input;
 898        self.output += &other.output;
 899    }
 900}
 901
 902#[derive(Clone, Debug)]
 903struct Fold(Range<Anchor>);
 904
 905impl Default for Fold {
 906    fn default() -> Self {
 907        Self(Anchor::min()..Anchor::max())
 908    }
 909}
 910
 911impl sum_tree::Item for Fold {
 912    type Summary = FoldSummary;
 913
 914    fn summary(&self) -> Self::Summary {
 915        FoldSummary {
 916            start: self.0.start.clone(),
 917            end: self.0.end.clone(),
 918            min_start: self.0.start.clone(),
 919            max_end: self.0.end.clone(),
 920            count: 1,
 921        }
 922    }
 923}
 924
 925#[derive(Clone, Debug)]
 926struct FoldSummary {
 927    start: Anchor,
 928    end: Anchor,
 929    min_start: Anchor,
 930    max_end: Anchor,
 931    count: usize,
 932}
 933
 934impl Default for FoldSummary {
 935    fn default() -> Self {
 936        Self {
 937            start: Anchor::min(),
 938            end: Anchor::max(),
 939            min_start: Anchor::max(),
 940            max_end: Anchor::min(),
 941            count: 0,
 942        }
 943    }
 944}
 945
 946impl sum_tree::Summary for FoldSummary {
 947    type Context = MultiBufferSnapshot;
 948
 949    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 950        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
 951            self.min_start = other.min_start.clone();
 952        }
 953        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
 954            self.max_end = other.max_end.clone();
 955        }
 956
 957        #[cfg(debug_assertions)]
 958        {
 959            let start_comparison = self.start.cmp(&other.start, buffer);
 960            assert!(start_comparison <= Ordering::Equal);
 961            if start_comparison == Ordering::Equal {
 962                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
 963            }
 964        }
 965
 966        self.start = other.start.clone();
 967        self.end = other.end.clone();
 968        self.count += other.count;
 969    }
 970}
 971
 972impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 973    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 974        self.0.start = summary.start.clone();
 975        self.0.end = summary.end.clone();
 976    }
 977}
 978
 979impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 980    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 981        self.0.cmp(&other.0, buffer)
 982    }
 983}
 984
 985impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 986    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 987        *self += summary.count;
 988    }
 989}
 990
 991pub struct FoldBufferRows<'a> {
 992    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 993    input_buffer_rows: MultiBufferRows<'a>,
 994    fold_point: FoldPoint,
 995}
 996
 997impl<'a> Iterator for FoldBufferRows<'a> {
 998    type Item = Option<u32>;
 999
1000    fn next(&mut self) -> Option<Self::Item> {
1001        let mut traversed_fold = false;
1002        while self.fold_point > self.cursor.end(&()).0 {
1003            self.cursor.next(&());
1004            traversed_fold = true;
1005            if self.cursor.item().is_none() {
1006                break;
1007            }
1008        }
1009
1010        if self.cursor.item().is_some() {
1011            if traversed_fold {
1012                self.input_buffer_rows.seek(self.cursor.start().1.row);
1013                self.input_buffer_rows.next();
1014            }
1015            *self.fold_point.row_mut() += 1;
1016            self.input_buffer_rows.next()
1017        } else {
1018            None
1019        }
1020    }
1021}
1022
1023pub struct FoldChunks<'a> {
1024    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1025    buffer_chunks: MultiBufferChunks<'a>,
1026    buffer_chunk: Option<(usize, Chunk<'a>)>,
1027    buffer_offset: usize,
1028    output_offset: usize,
1029    max_output_offset: usize,
1030    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1031    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1032}
1033
1034impl<'a> Iterator for FoldChunks<'a> {
1035    type Item = Chunk<'a>;
1036
1037    fn next(&mut self) -> Option<Self::Item> {
1038        if self.output_offset >= self.max_output_offset {
1039            return None;
1040        }
1041
1042        let transform = self.transform_cursor.item()?;
1043
1044        // If we're in a fold, then return the fold's display text and
1045        // advance the transform and buffer cursors to the end of the fold.
1046        if let Some(output_text) = transform.output_text {
1047            self.buffer_chunk.take();
1048            self.buffer_offset += transform.summary.input.len;
1049            self.buffer_chunks.seek(self.buffer_offset);
1050
1051            while self.buffer_offset >= self.transform_cursor.end(&()).1
1052                && self.transform_cursor.item().is_some()
1053            {
1054                self.transform_cursor.next(&());
1055            }
1056
1057            self.output_offset += output_text.len();
1058            return Some(Chunk {
1059                text: output_text,
1060                syntax_highlight_id: None,
1061                highlight_style: None,
1062                diagnostic_severity: None,
1063                is_unnecessary: false,
1064            });
1065        }
1066
1067        let mut next_highlight_endpoint = usize::MAX;
1068        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1069            if endpoint.offset <= self.buffer_offset {
1070                if endpoint.is_start {
1071                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1072                } else {
1073                    self.active_highlights.remove(&endpoint.tag);
1074                }
1075                self.highlight_endpoints.next();
1076            } else {
1077                next_highlight_endpoint = endpoint.offset;
1078                break;
1079            }
1080        }
1081
1082        // Retrieve a chunk from the current location in the buffer.
1083        if self.buffer_chunk.is_none() {
1084            let chunk_offset = self.buffer_chunks.offset();
1085            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1086        }
1087
1088        // Otherwise, take a chunk from the buffer's text.
1089        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1090            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1091            let transform_end = self.transform_cursor.end(&()).1;
1092            let chunk_end = buffer_chunk_end
1093                .min(transform_end)
1094                .min(next_highlight_endpoint);
1095
1096            chunk.text = &chunk.text
1097                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1098
1099            if !self.active_highlights.is_empty() {
1100                let mut highlight_style = HighlightStyle::default();
1101                for active_highlight in self.active_highlights.values() {
1102                    highlight_style.highlight(*active_highlight);
1103                }
1104                chunk.highlight_style = Some(highlight_style);
1105            }
1106
1107            if chunk_end == transform_end {
1108                self.transform_cursor.next(&());
1109            } else if chunk_end == buffer_chunk_end {
1110                self.buffer_chunk.take();
1111            }
1112
1113            self.buffer_offset = chunk_end;
1114            self.output_offset += chunk.text.len();
1115            return Some(chunk);
1116        }
1117
1118        None
1119    }
1120}
1121
1122#[derive(Copy, Clone, Eq, PartialEq)]
1123struct HighlightEndpoint {
1124    offset: usize,
1125    is_start: bool,
1126    tag: Option<TypeId>,
1127    style: HighlightStyle,
1128}
1129
1130impl PartialOrd for HighlightEndpoint {
1131    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1132        Some(self.cmp(other))
1133    }
1134}
1135
1136impl Ord for HighlightEndpoint {
1137    fn cmp(&self, other: &Self) -> Ordering {
1138        self.offset
1139            .cmp(&other.offset)
1140            .then_with(|| other.is_start.cmp(&self.is_start))
1141    }
1142}
1143
1144#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1145pub struct FoldOffset(pub usize);
1146
1147impl FoldOffset {
1148    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1149        let mut cursor = snapshot
1150            .transforms
1151            .cursor::<(FoldOffset, TransformSummary)>();
1152        cursor.seek(&self, Bias::Right, &());
1153        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1154            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1155        } else {
1156            let buffer_offset = cursor.start().1.input.len + self.0 - cursor.start().0 .0;
1157            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1158            buffer_point - cursor.start().1.input.lines
1159        };
1160        FoldPoint(cursor.start().1.output.lines + overshoot)
1161    }
1162}
1163
1164impl Sub for FoldOffset {
1165    type Output = Self;
1166
1167    fn sub(self, rhs: Self) -> Self::Output {
1168        Self(self.0 - rhs.0)
1169    }
1170}
1171
1172impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1173    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1174        self.0 += &summary.output.len;
1175    }
1176}
1177
1178impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1179    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1180        *self += &summary.input.lines;
1181    }
1182}
1183
1184impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1185    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1186        *self += &summary.input.len;
1187    }
1188}
1189
1190pub type FoldEdit = Edit<FoldOffset>;
1191
1192#[cfg(test)]
1193mod tests {
1194    use super::*;
1195    use crate::{MultiBuffer, ToPoint};
1196    use rand::prelude::*;
1197    use settings::Settings;
1198    use std::{cmp::Reverse, env, mem, sync::Arc};
1199    use sum_tree::TreeMap;
1200    use util::test::sample_text;
1201    use util::RandomCharIter;
1202    use Bias::{Left, Right};
1203
1204    #[gpui::test]
1205    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1206        cx.set_global(Settings::test(cx));
1207        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1208        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1209        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1210        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1211
1212        let (mut writer, _, _) = map.write(buffer_snapshot, vec![]);
1213        let (snapshot2, edits) = writer.fold(vec![
1214            Point::new(0, 2)..Point::new(2, 2),
1215            Point::new(2, 4)..Point::new(4, 1),
1216        ]);
1217        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1218        assert_eq!(
1219            edits,
1220            &[
1221                FoldEdit {
1222                    old: FoldOffset(2)..FoldOffset(16),
1223                    new: FoldOffset(2)..FoldOffset(5),
1224                },
1225                FoldEdit {
1226                    old: FoldOffset(18)..FoldOffset(29),
1227                    new: FoldOffset(7)..FoldOffset(10)
1228                },
1229            ]
1230        );
1231
1232        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1233            buffer.edit(
1234                vec![
1235                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1236                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1237                ],
1238                None,
1239                cx,
1240            );
1241            buffer.snapshot(cx)
1242        });
1243        let (snapshot3, edits) = map.read(buffer_snapshot, subscription.consume().into_inner());
1244        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1245        assert_eq!(
1246            edits,
1247            &[
1248                FoldEdit {
1249                    old: FoldOffset(0)..FoldOffset(1),
1250                    new: FoldOffset(0)..FoldOffset(3),
1251                },
1252                FoldEdit {
1253                    old: FoldOffset(6)..FoldOffset(6),
1254                    new: FoldOffset(8)..FoldOffset(11),
1255                },
1256            ]
1257        );
1258
1259        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1260            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1261            buffer.snapshot(cx)
1262        });
1263        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1264        assert_eq!(snapshot4.text(), "123a…c123456eee");
1265
1266        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1267        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1268        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1269        assert_eq!(snapshot5.text(), "123a…c123456eee");
1270
1271        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1272        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1273        let (snapshot6, _) = map.read(buffer_snapshot, vec![]);
1274        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1275    }
1276
1277    #[gpui::test]
1278    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1279        cx.set_global(Settings::test(cx));
1280        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1281        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1282        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1283
1284        {
1285            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1286
1287            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1288            writer.fold(vec![5..8]);
1289            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1290            assert_eq!(snapshot.text(), "abcde…ijkl");
1291
1292            // Create an fold adjacent to the start of the first fold.
1293            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1294            writer.fold(vec![0..1, 2..5]);
1295            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1296            assert_eq!(snapshot.text(), "…b…ijkl");
1297
1298            // Create an fold adjacent to the end of the first fold.
1299            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1300            writer.fold(vec![11..11, 8..10]);
1301            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1302            assert_eq!(snapshot.text(), "…b…kl");
1303        }
1304
1305        {
1306            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1307
1308            // Create two adjacent folds.
1309            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1310            writer.fold(vec![0..2, 2..5]);
1311            let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1312            assert_eq!(snapshot.text(), "…fghijkl");
1313
1314            // Edit within one of the folds.
1315            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1316                buffer.edit([(0..1, "12345")], None, cx);
1317                buffer.snapshot(cx)
1318            });
1319            let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1320            assert_eq!(snapshot.text(), "12345…fghijkl");
1321        }
1322    }
1323
1324    #[gpui::test]
1325    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1326        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1327        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1328        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1329        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1330        writer.fold(vec![
1331            Point::new(0, 2)..Point::new(2, 2),
1332            Point::new(0, 4)..Point::new(1, 0),
1333            Point::new(1, 2)..Point::new(3, 2),
1334            Point::new(3, 1)..Point::new(4, 1),
1335        ]);
1336        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1337        assert_eq!(snapshot.text(), "aa…eeeee");
1338    }
1339
1340    #[gpui::test]
1341    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1342        cx.set_global(Settings::test(cx));
1343        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1344        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1345        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1346        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1347
1348        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1349        writer.fold(vec![
1350            Point::new(0, 2)..Point::new(2, 2),
1351            Point::new(3, 1)..Point::new(4, 1),
1352        ]);
1353        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1354        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1355
1356        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1357            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1358            buffer.snapshot(cx)
1359        });
1360        let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1361        assert_eq!(snapshot.text(), "aa…eeeee");
1362    }
1363
1364    #[gpui::test]
1365    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1366        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1367        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1368        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1369
1370        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1371        writer.fold(vec![
1372            Point::new(0, 2)..Point::new(2, 2),
1373            Point::new(0, 4)..Point::new(1, 0),
1374            Point::new(1, 2)..Point::new(3, 2),
1375            Point::new(3, 1)..Point::new(4, 1),
1376        ]);
1377        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1378        let fold_ranges = snapshot
1379            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1380            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1381            .collect::<Vec<_>>();
1382        assert_eq!(
1383            fold_ranges,
1384            vec![
1385                Point::new(0, 2)..Point::new(2, 2),
1386                Point::new(1, 2)..Point::new(3, 2)
1387            ]
1388        );
1389    }
1390
1391    #[gpui::test(iterations = 100)]
1392    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1393        cx.set_global(Settings::test(cx));
1394        let operations = env::var("OPERATIONS")
1395            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1396            .unwrap_or(10);
1397
1398        let len = rng.gen_range(0..10);
1399        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1400        let buffer = if rng.gen() {
1401            MultiBuffer::build_simple(&text, cx)
1402        } else {
1403            MultiBuffer::build_random(&mut rng, cx)
1404        };
1405        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1406        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1407
1408        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1409        let mut snapshot_edits = Vec::new();
1410
1411        let mut highlights = TreeMap::default();
1412        let highlight_count = rng.gen_range(0_usize..10);
1413        let mut highlight_ranges = (0..highlight_count)
1414            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1415            .collect::<Vec<_>>();
1416        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1417        log::info!("highlighting ranges {:?}", highlight_ranges);
1418        let highlight_ranges = highlight_ranges
1419            .into_iter()
1420            .map(|range| {
1421                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1422            })
1423            .collect::<Vec<_>>();
1424
1425        highlights.insert(
1426            Some(TypeId::of::<()>()),
1427            Arc::new((HighlightStyle::default(), highlight_ranges)),
1428        );
1429
1430        for _ in 0..operations {
1431            log::info!("text: {:?}", buffer_snapshot.text());
1432            let mut buffer_edits = Vec::new();
1433            match rng.gen_range(0..=100) {
1434                0..=59 => {
1435                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1436                }
1437                _ => buffer.update(cx, |buffer, cx| {
1438                    let subscription = buffer.subscribe();
1439                    let edit_count = rng.gen_range(1..=5);
1440                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1441                    buffer_snapshot = buffer.snapshot(cx);
1442                    let edits = subscription.consume().into_inner();
1443                    log::info!("editing {:?}", edits);
1444                    buffer_edits.extend(edits);
1445                }),
1446            };
1447
1448            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1449            snapshot_edits.push((snapshot.clone(), edits));
1450
1451            let mut expected_text: String = buffer_snapshot.text().to_string();
1452            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1453                expected_text.replace_range(fold_range.start..fold_range.end, "…");
1454            }
1455
1456            assert_eq!(snapshot.text(), expected_text);
1457            log::info!(
1458                "fold text {:?} ({} lines)",
1459                expected_text,
1460                expected_text.matches('\n').count() + 1
1461            );
1462
1463            let mut prev_row = 0;
1464            let mut expected_buffer_rows = Vec::new();
1465            for fold_range in map.merged_fold_ranges().into_iter() {
1466                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1467                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1468                expected_buffer_rows.extend(
1469                    buffer_snapshot
1470                        .buffer_rows(prev_row)
1471                        .take((1 + fold_start - prev_row) as usize),
1472                );
1473                prev_row = 1 + fold_end;
1474            }
1475            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1476
1477            assert_eq!(
1478                expected_buffer_rows.len(),
1479                expected_text.matches('\n').count() + 1,
1480                "wrong expected buffer rows {:?}. text: {:?}",
1481                expected_buffer_rows,
1482                expected_text
1483            );
1484
1485            for (output_row, line) in expected_text.lines().enumerate() {
1486                let line_len = snapshot.line_len(output_row as u32);
1487                assert_eq!(line_len, line.len() as u32);
1488            }
1489
1490            let longest_row = snapshot.longest_row();
1491            let longest_char_column = expected_text
1492                .split('\n')
1493                .nth(longest_row as usize)
1494                .unwrap()
1495                .chars()
1496                .count();
1497            let mut fold_point = FoldPoint::new(0, 0);
1498            let mut fold_offset = FoldOffset(0);
1499            let mut char_column = 0;
1500            for c in expected_text.chars() {
1501                let buffer_point = fold_point.to_buffer_point(&snapshot);
1502                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1503                assert_eq!(
1504                    snapshot.to_fold_point(buffer_point, Right),
1505                    fold_point,
1506                    "{:?} -> fold point",
1507                    buffer_point,
1508                );
1509                assert_eq!(
1510                    fold_point.to_buffer_offset(&snapshot),
1511                    buffer_offset,
1512                    "fold_point.to_buffer_offset({:?})",
1513                    fold_point,
1514                );
1515                assert_eq!(
1516                    fold_point.to_offset(&snapshot),
1517                    fold_offset,
1518                    "fold_point.to_offset({:?})",
1519                    fold_point,
1520                );
1521
1522                if c == '\n' {
1523                    *fold_point.row_mut() += 1;
1524                    *fold_point.column_mut() = 0;
1525                    char_column = 0;
1526                } else {
1527                    *fold_point.column_mut() += c.len_utf8() as u32;
1528                    char_column += 1;
1529                }
1530                fold_offset.0 += c.len_utf8();
1531                if char_column > longest_char_column {
1532                    panic!(
1533                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1534                        longest_row,
1535                        longest_char_column,
1536                        fold_point.row(),
1537                        char_column
1538                    );
1539                }
1540            }
1541
1542            for _ in 0..5 {
1543                let mut start = snapshot
1544                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1545                let mut end = snapshot
1546                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1547                if start > end {
1548                    mem::swap(&mut start, &mut end);
1549                }
1550
1551                let text = &expected_text[start.0..end.0];
1552                assert_eq!(
1553                    snapshot
1554                        .chunks(start..end, false, Some(&highlights))
1555                        .map(|c| c.text)
1556                        .collect::<String>(),
1557                    text,
1558                );
1559            }
1560
1561            let mut fold_row = 0;
1562            while fold_row < expected_buffer_rows.len() as u32 {
1563                fold_row = snapshot
1564                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1565                    .row();
1566                assert_eq!(
1567                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1568                    expected_buffer_rows[(fold_row as usize)..],
1569                    "wrong buffer rows starting at fold row {}",
1570                    fold_row,
1571                );
1572                fold_row += 1;
1573            }
1574
1575            for fold_range in map.merged_fold_ranges() {
1576                let fold_point =
1577                    snapshot.to_fold_point(fold_range.start.to_point(&buffer_snapshot), Right);
1578                assert!(snapshot.is_line_folded(fold_point.row()));
1579            }
1580
1581            for _ in 0..5 {
1582                let end =
1583                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1584                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1585                let expected_folds = map
1586                    .folds
1587                    .items(&buffer_snapshot)
1588                    .into_iter()
1589                    .filter(|fold| {
1590                        let start = buffer_snapshot.anchor_before(start);
1591                        let end = buffer_snapshot.anchor_after(end);
1592                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1593                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1594                    })
1595                    .map(|fold| fold.0)
1596                    .collect::<Vec<_>>();
1597
1598                assert_eq!(
1599                    snapshot
1600                        .folds_in_range(start..end)
1601                        .cloned()
1602                        .collect::<Vec<_>>(),
1603                    expected_folds
1604                );
1605            }
1606
1607            let text = snapshot.text();
1608            for _ in 0..5 {
1609                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1610                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1611                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1612                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1613                let mut start =
1614                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1615                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1616                if start > end {
1617                    mem::swap(&mut start, &mut end);
1618                }
1619
1620                let lines = start..end;
1621                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1622                assert_eq!(
1623                    snapshot.text_summary_for_range(lines),
1624                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1625                )
1626            }
1627
1628            let mut text = initial_snapshot.text();
1629            for (snapshot, edits) in snapshot_edits.drain(..) {
1630                let new_text = snapshot.text();
1631                for edit in edits {
1632                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1633                    let new_bytes = edit.new.start.0..edit.new.end.0;
1634                    text.replace_range(old_bytes, &new_text[new_bytes]);
1635                }
1636
1637                assert_eq!(text, new_text);
1638                initial_snapshot = snapshot;
1639            }
1640        }
1641    }
1642
1643    #[gpui::test]
1644    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1645        let text = sample_text(6, 6, 'a') + "\n";
1646        let buffer = MultiBuffer::build_simple(&text, cx);
1647
1648        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1649        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1650
1651        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1652        writer.fold(vec![
1653            Point::new(0, 2)..Point::new(2, 2),
1654            Point::new(3, 1)..Point::new(4, 1),
1655        ]);
1656
1657        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1658        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1659        assert_eq!(
1660            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1661            [Some(0), Some(3), Some(5), Some(6)]
1662        );
1663        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1664    }
1665
1666    impl FoldMap {
1667        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1668            let buffer = self.buffer.lock().clone();
1669            let mut folds = self.folds.items(&buffer);
1670            // Ensure sorting doesn't change how folds get merged and displayed.
1671            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer));
1672            let mut fold_ranges = folds
1673                .iter()
1674                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1675                .peekable();
1676
1677            let mut merged_ranges = Vec::new();
1678            while let Some(mut fold_range) = fold_ranges.next() {
1679                while let Some(next_range) = fold_ranges.peek() {
1680                    if fold_range.end >= next_range.start {
1681                        if next_range.end > fold_range.end {
1682                            fold_range.end = next_range.end;
1683                        }
1684                        fold_ranges.next();
1685                    } else {
1686                        break;
1687                    }
1688                }
1689                if fold_range.end > fold_range.start {
1690                    merged_ranges.push(fold_range);
1691                }
1692            }
1693            merged_ranges
1694        }
1695
1696        pub fn randomly_mutate(
1697            &mut self,
1698            rng: &mut impl Rng,
1699        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1700            let mut snapshot_edits = Vec::new();
1701            match rng.gen_range(0..=100) {
1702                0..=39 if !self.folds.is_empty() => {
1703                    let buffer = self.buffer.lock().clone();
1704                    let mut to_unfold = Vec::new();
1705                    for _ in 0..rng.gen_range(1..=3) {
1706                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1707                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1708                        to_unfold.push(start..end);
1709                    }
1710                    log::info!("unfolding {:?}", to_unfold);
1711                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1712                    snapshot_edits.push((snapshot, edits));
1713                    let (snapshot, edits) = writer.fold(to_unfold);
1714                    snapshot_edits.push((snapshot, edits));
1715                }
1716                _ => {
1717                    let buffer = self.buffer.lock().clone();
1718                    let mut to_fold = Vec::new();
1719                    for _ in 0..rng.gen_range(1..=2) {
1720                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1721                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1722                        to_fold.push(start..end);
1723                    }
1724                    log::info!("folding {:?}", to_fold);
1725                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1726                    snapshot_edits.push((snapshot, edits));
1727                    let (snapshot, edits) = writer.fold(to_fold);
1728                    snapshot_edits.push((snapshot, edits));
1729                }
1730            }
1731            snapshot_edits
1732        }
1733    }
1734}