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, Point, TextSummary};
   9use parking_lot::Mutex;
  10use std::{
  11    any::TypeId,
  12    cmp::{self, Ordering},
  13    iter::{self, Peekable},
  14    ops::{Range, Sub},
  15    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  16    vec,
  17};
  18use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  19
  20#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  21pub struct FoldPoint(pub super::Point);
  22
  23impl FoldPoint {
  24    pub fn new(row: u32, column: u32) -> Self {
  25        Self(super::Point::new(row, column))
  26    }
  27
  28    pub fn row(self) -> u32 {
  29        self.0.row
  30    }
  31
  32    pub fn column(self) -> u32 {
  33        self.0.column
  34    }
  35
  36    pub fn row_mut(&mut self) -> &mut u32 {
  37        &mut self.0.row
  38    }
  39
  40    pub fn column_mut(&mut self) -> &mut u32 {
  41        &mut self.0.column
  42    }
  43
  44    pub fn to_buffer_point(&self, snapshot: &FoldSnapshot) -> Point {
  45        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  46        cursor.seek(self, Bias::Right, &());
  47        let overshoot = self.0 - cursor.start().0 .0;
  48        cursor.start().1 + overshoot
  49    }
  50
  51    pub fn to_buffer_offset(&self, snapshot: &FoldSnapshot) -> usize {
  52        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  53        cursor.seek(self, Bias::Right, &());
  54        let overshoot = self.0 - cursor.start().0 .0;
  55        snapshot
  56            .buffer_snapshot
  57            .point_to_offset(cursor.start().1 + overshoot)
  58    }
  59
  60    pub fn to_offset(&self, snapshot: &FoldSnapshot) -> FoldOffset {
  61        let mut cursor = snapshot
  62            .transforms
  63            .cursor::<(FoldPoint, TransformSummary)>();
  64        cursor.seek(self, Bias::Right, &());
  65        let overshoot = self.0 - cursor.start().1.output.lines;
  66        let mut offset = cursor.start().1.output.bytes;
  67        if !overshoot.is_zero() {
  68            let transform = cursor.item().expect("display point out of range");
  69            assert!(transform.output_text.is_none());
  70            let end_buffer_offset = snapshot
  71                .buffer_snapshot
  72                .point_to_offset(cursor.start().1.input.lines + overshoot);
  73            offset += end_buffer_offset - cursor.start().1.input.bytes;
  74        }
  75        FoldOffset(offset)
  76    }
  77}
  78
  79impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
  80    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
  81        self.0 += &summary.output.lines;
  82    }
  83}
  84
  85pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  86
  87impl<'a> FoldMapWriter<'a> {
  88    pub fn fold<T: ToOffset>(
  89        &mut self,
  90        ranges: impl IntoIterator<Item = Range<T>>,
  91    ) -> (FoldSnapshot, Vec<FoldEdit>) {
  92        let mut edits = Vec::new();
  93        let mut folds = Vec::new();
  94        let buffer = self.0.buffer.lock().clone();
  95        for range in ranges.into_iter() {
  96            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
  97
  98            // Ignore any empty ranges.
  99            if range.start == range.end {
 100                continue;
 101            }
 102
 103            // For now, ignore any ranges that span an excerpt boundary.
 104            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 105            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 106                continue;
 107            }
 108
 109            folds.push(fold);
 110            edits.push(text::Edit {
 111                old: range.clone(),
 112                new: range,
 113            });
 114        }
 115
 116        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 117
 118        self.0.folds = {
 119            let mut new_tree = SumTree::new();
 120            let mut cursor = self.0.folds.cursor::<Fold>();
 121            for fold in folds {
 122                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 123                new_tree.push(fold, &buffer);
 124            }
 125            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 126            new_tree
 127        };
 128
 129        consolidate_buffer_edits(&mut edits);
 130        let edits = self.0.sync(buffer.clone(), edits);
 131        let snapshot = FoldSnapshot {
 132            transforms: self.0.transforms.lock().clone(),
 133            folds: self.0.folds.clone(),
 134            buffer_snapshot: buffer,
 135            version: self.0.version.load(SeqCst),
 136        };
 137        (snapshot, edits)
 138    }
 139
 140    pub fn unfold<T: ToOffset>(
 141        &mut self,
 142        ranges: impl IntoIterator<Item = Range<T>>,
 143        inclusive: bool,
 144    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 145        let mut edits = Vec::new();
 146        let mut fold_ixs_to_delete = Vec::new();
 147        let buffer = self.0.buffer.lock().clone();
 148        for range in ranges.into_iter() {
 149            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 150            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, inclusive);
 151            while let Some(fold) = folds_cursor.item() {
 152                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 153                if offset_range.end > offset_range.start {
 154                    edits.push(text::Edit {
 155                        old: offset_range.clone(),
 156                        new: offset_range,
 157                    });
 158                }
 159                fold_ixs_to_delete.push(*folds_cursor.start());
 160                folds_cursor.next(&buffer);
 161            }
 162        }
 163
 164        fold_ixs_to_delete.sort_unstable();
 165        fold_ixs_to_delete.dedup();
 166
 167        self.0.folds = {
 168            let mut cursor = self.0.folds.cursor::<usize>();
 169            let mut folds = SumTree::new();
 170            for fold_ix in fold_ixs_to_delete {
 171                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 172                cursor.next(&buffer);
 173            }
 174            folds.push_tree(cursor.suffix(&buffer), &buffer);
 175            folds
 176        };
 177
 178        consolidate_buffer_edits(&mut edits);
 179        let edits = self.0.sync(buffer.clone(), edits);
 180        let snapshot = FoldSnapshot {
 181            transforms: self.0.transforms.lock().clone(),
 182            folds: self.0.folds.clone(),
 183            buffer_snapshot: buffer,
 184            version: self.0.version.load(SeqCst),
 185        };
 186        (snapshot, edits)
 187    }
 188}
 189
 190pub struct FoldMap {
 191    buffer: Mutex<MultiBufferSnapshot>,
 192    transforms: Mutex<SumTree<Transform>>,
 193    folds: SumTree<Fold>,
 194    version: AtomicUsize,
 195}
 196
 197impl FoldMap {
 198    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 199        let this = Self {
 200            buffer: Mutex::new(buffer.clone()),
 201            folds: Default::default(),
 202            transforms: Mutex::new(SumTree::from_item(
 203                Transform {
 204                    summary: TransformSummary {
 205                        input: buffer.text_summary(),
 206                        output: buffer.text_summary(),
 207                    },
 208                    output_text: None,
 209                },
 210                &(),
 211            )),
 212            version: Default::default(),
 213        };
 214
 215        let snapshot = FoldSnapshot {
 216            transforms: this.transforms.lock().clone(),
 217            folds: this.folds.clone(),
 218            buffer_snapshot: this.buffer.lock().clone(),
 219            version: this.version.load(SeqCst),
 220        };
 221        (this, snapshot)
 222    }
 223
 224    pub fn read(
 225        &self,
 226        buffer: MultiBufferSnapshot,
 227        edits: Vec<Edit<usize>>,
 228    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 229        let edits = self.sync(buffer, edits);
 230        self.check_invariants();
 231        let snapshot = FoldSnapshot {
 232            transforms: self.transforms.lock().clone(),
 233            folds: self.folds.clone(),
 234            buffer_snapshot: self.buffer.lock().clone(),
 235            version: self.version.load(SeqCst),
 236        };
 237        (snapshot, edits)
 238    }
 239
 240    pub fn write(
 241        &mut self,
 242        buffer: MultiBufferSnapshot,
 243        edits: Vec<Edit<usize>>,
 244    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 245        let (snapshot, edits) = self.read(buffer, edits);
 246        (FoldMapWriter(self), snapshot, edits)
 247    }
 248
 249    fn check_invariants(&self) {
 250        if cfg!(test) {
 251            assert_eq!(
 252                self.transforms.lock().summary().input.bytes,
 253                self.buffer.lock().len(),
 254                "transform tree does not match buffer's length"
 255            );
 256
 257            let mut folds = self.folds.iter().peekable();
 258            while let Some(fold) = folds.next() {
 259                if let Some(next_fold) = folds.peek() {
 260                    let comparison = fold.0.cmp(&next_fold.0, &self.buffer.lock());
 261                    assert!(comparison.is_le());
 262                }
 263            }
 264        }
 265    }
 266
 267    fn sync(
 268        &self,
 269        new_buffer: MultiBufferSnapshot,
 270        buffer_edits: Vec<text::Edit<usize>>,
 271    ) -> Vec<FoldEdit> {
 272        if buffer_edits.is_empty() {
 273            let mut buffer = self.buffer.lock();
 274            if buffer.edit_count() != new_buffer.edit_count()
 275                || buffer.parse_count() != new_buffer.parse_count()
 276                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 277                || buffer.trailing_excerpt_update_count()
 278                    != new_buffer.trailing_excerpt_update_count()
 279            {
 280                self.version.fetch_add(1, SeqCst);
 281            }
 282            *buffer = new_buffer;
 283            Vec::new()
 284        } else {
 285            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 286
 287            let mut new_transforms = SumTree::new();
 288            let mut transforms = self.transforms.lock();
 289            let mut cursor = transforms.cursor::<usize>();
 290            cursor.seek(&0, Bias::Right, &());
 291
 292            while let Some(mut edit) = buffer_edits_iter.next() {
 293                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 294                edit.new.start -= edit.old.start - cursor.start();
 295                edit.old.start = *cursor.start();
 296
 297                cursor.seek(&edit.old.end, Bias::Right, &());
 298                cursor.next(&());
 299
 300                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 301                loop {
 302                    edit.old.end = *cursor.start();
 303
 304                    if let Some(next_edit) = buffer_edits_iter.peek() {
 305                        if next_edit.old.start > edit.old.end {
 306                            break;
 307                        }
 308
 309                        let next_edit = buffer_edits_iter.next().unwrap();
 310                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 311
 312                        if next_edit.old.end >= edit.old.end {
 313                            edit.old.end = next_edit.old.end;
 314                            cursor.seek(&edit.old.end, Bias::Right, &());
 315                            cursor.next(&());
 316                        }
 317                    } else {
 318                        break;
 319                    }
 320                }
 321
 322                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 323
 324                let anchor = new_buffer.anchor_before(edit.new.start);
 325                let mut folds_cursor = self.folds.cursor::<Fold>();
 326                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 327
 328                let mut folds = iter::from_fn({
 329                    let buffer = &new_buffer;
 330                    move || {
 331                        let item = folds_cursor
 332                            .item()
 333                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 334                        folds_cursor.next(buffer);
 335                        item
 336                    }
 337                })
 338                .peekable();
 339
 340                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 341                    let mut fold = folds.next().unwrap();
 342                    let sum = new_transforms.summary();
 343
 344                    assert!(fold.start >= sum.input.bytes);
 345
 346                    while folds
 347                        .peek()
 348                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 349                    {
 350                        let next_fold = folds.next().unwrap();
 351                        if next_fold.end > fold.end {
 352                            fold.end = next_fold.end;
 353                        }
 354                    }
 355
 356                    if fold.start > sum.input.bytes {
 357                        let text_summary = new_buffer
 358                            .text_summary_for_range::<TextSummary, _>(sum.input.bytes..fold.start);
 359                        new_transforms.push(
 360                            Transform {
 361                                summary: TransformSummary {
 362                                    output: text_summary.clone(),
 363                                    input: text_summary,
 364                                },
 365                                output_text: None,
 366                            },
 367                            &(),
 368                        );
 369                    }
 370
 371                    if fold.end > fold.start {
 372                        let output_text = "…";
 373                        new_transforms.push(
 374                            Transform {
 375                                summary: TransformSummary {
 376                                    output: TextSummary::from(output_text),
 377                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 378                                },
 379                                output_text: Some(output_text),
 380                            },
 381                            &(),
 382                        );
 383                    }
 384                }
 385
 386                let sum = new_transforms.summary();
 387                if sum.input.bytes < edit.new.end {
 388                    let text_summary = new_buffer
 389                        .text_summary_for_range::<TextSummary, _>(sum.input.bytes..edit.new.end);
 390                    new_transforms.push(
 391                        Transform {
 392                            summary: TransformSummary {
 393                                output: text_summary.clone(),
 394                                input: text_summary,
 395                            },
 396                            output_text: None,
 397                        },
 398                        &(),
 399                    );
 400                }
 401            }
 402
 403            new_transforms.push_tree(cursor.suffix(&()), &());
 404            if new_transforms.is_empty() {
 405                let text_summary = new_buffer.text_summary();
 406                new_transforms.push(
 407                    Transform {
 408                        summary: TransformSummary {
 409                            output: text_summary.clone(),
 410                            input: text_summary,
 411                        },
 412                        output_text: None,
 413                    },
 414                    &(),
 415                );
 416            }
 417
 418            drop(cursor);
 419
 420            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 421            {
 422                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 423                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 424
 425                for mut edit in buffer_edits {
 426                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 427                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 428                        edit.old.start = old_transforms.start().0;
 429                    }
 430                    let old_start =
 431                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 432
 433                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 434                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 435                        old_transforms.next(&());
 436                        edit.old.end = old_transforms.start().0;
 437                    }
 438                    let old_end =
 439                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 440
 441                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 442                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 443                        edit.new.start = new_transforms.start().0;
 444                    }
 445                    let new_start =
 446                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 447
 448                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 449                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 450                        new_transforms.next(&());
 451                        edit.new.end = new_transforms.start().0;
 452                    }
 453                    let new_end =
 454                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 455
 456                    fold_edits.push(FoldEdit {
 457                        old: FoldOffset(old_start)..FoldOffset(old_end),
 458                        new: FoldOffset(new_start)..FoldOffset(new_end),
 459                    });
 460                }
 461
 462                consolidate_fold_edits(&mut fold_edits);
 463            }
 464
 465            *transforms = new_transforms;
 466            *self.buffer.lock() = new_buffer;
 467            self.version.fetch_add(1, SeqCst);
 468            fold_edits
 469        }
 470    }
 471}
 472
 473#[derive(Clone)]
 474pub struct FoldSnapshot {
 475    transforms: SumTree<Transform>,
 476    folds: SumTree<Fold>,
 477    buffer_snapshot: MultiBufferSnapshot,
 478    pub version: usize,
 479}
 480
 481impl FoldSnapshot {
 482    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 483        &self.buffer_snapshot
 484    }
 485
 486    #[cfg(test)]
 487    pub fn text(&self) -> String {
 488        self.chunks(FoldOffset(0)..self.len(), false, None)
 489            .map(|c| c.text)
 490            .collect()
 491    }
 492
 493    #[cfg(test)]
 494    pub fn fold_count(&self) -> usize {
 495        self.folds.items(&self.buffer_snapshot).len()
 496    }
 497
 498    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 499        let mut summary = TextSummary::default();
 500
 501        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 502        cursor.seek(&range.start, Bias::Right, &());
 503        if let Some(transform) = cursor.item() {
 504            let start_in_transform = range.start.0 - cursor.start().0 .0;
 505            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 506            if let Some(output_text) = transform.output_text {
 507                summary = TextSummary::from(
 508                    &output_text
 509                        [start_in_transform.column as usize..end_in_transform.column as usize],
 510                );
 511            } else {
 512                let buffer_start = cursor.start().1 + start_in_transform;
 513                let buffer_end = cursor.start().1 + end_in_transform;
 514                summary = self
 515                    .buffer_snapshot
 516                    .text_summary_for_range(buffer_start..buffer_end);
 517            }
 518        }
 519
 520        if range.end > cursor.end(&()).0 {
 521            cursor.next(&());
 522            summary += &cursor
 523                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 524                .output;
 525            if let Some(transform) = cursor.item() {
 526                let end_in_transform = range.end.0 - cursor.start().0 .0;
 527                if let Some(output_text) = transform.output_text {
 528                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 529                } else {
 530                    let buffer_start = cursor.start().1;
 531                    let buffer_end = cursor.start().1 + end_in_transform;
 532                    summary += self
 533                        .buffer_snapshot
 534                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 535                }
 536            }
 537        }
 538
 539        summary
 540    }
 541
 542    pub fn to_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
 543        let mut cursor = self.transforms.cursor::<(Point, FoldPoint)>();
 544        cursor.seek(&point, Bias::Right, &());
 545        if cursor.item().map_or(false, |t| t.is_fold()) {
 546            if bias == Bias::Left || point == cursor.start().0 {
 547                cursor.start().1
 548            } else {
 549                cursor.end(&()).1
 550            }
 551        } else {
 552            let overshoot = point - cursor.start().0;
 553            FoldPoint(cmp::min(
 554                cursor.start().1 .0 + overshoot,
 555                cursor.end(&()).1 .0,
 556            ))
 557        }
 558    }
 559
 560    pub fn len(&self) -> FoldOffset {
 561        FoldOffset(self.transforms.summary().output.bytes)
 562    }
 563
 564    pub fn line_len(&self, row: u32) -> u32 {
 565        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 566        let line_end = if row >= self.max_point().row() {
 567            self.len().0
 568        } else {
 569            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 570        };
 571        (line_end - line_start) as u32
 572    }
 573
 574    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 575        if start_row > self.transforms.summary().output.lines.row {
 576            panic!("invalid display row {}", start_row);
 577        }
 578
 579        let fold_point = FoldPoint::new(start_row, 0);
 580        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 581        cursor.seek(&fold_point, Bias::Left, &());
 582
 583        let overshoot = fold_point.0 - cursor.start().0 .0;
 584        let buffer_point = cursor.start().1 + overshoot;
 585        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 586
 587        FoldBufferRows {
 588            fold_point,
 589            input_buffer_rows,
 590            cursor,
 591        }
 592    }
 593
 594    pub fn max_point(&self) -> FoldPoint {
 595        FoldPoint(self.transforms.summary().output.lines)
 596    }
 597
 598    #[cfg(test)]
 599    pub fn longest_row(&self) -> u32 {
 600        self.transforms.summary().output.longest_row
 601    }
 602
 603    pub fn folds_in_range<'a, T>(
 604        &'a self,
 605        range: Range<T>,
 606    ) -> impl Iterator<Item = &'a Range<Anchor>>
 607    where
 608        T: ToOffset,
 609    {
 610        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 611        iter::from_fn(move || {
 612            let item = folds.item().map(|f| &f.0);
 613            folds.next(&self.buffer_snapshot);
 614            item
 615        })
 616    }
 617
 618    pub fn intersects_fold<T>(&self, offset: T) -> bool
 619    where
 620        T: ToOffset,
 621    {
 622        let offset = offset.to_offset(&self.buffer_snapshot);
 623        let mut cursor = self.transforms.cursor::<usize>();
 624        cursor.seek(&offset, Bias::Right, &());
 625        cursor.item().map_or(false, |t| t.output_text.is_some())
 626    }
 627
 628    pub fn is_line_folded(&self, output_row: u32) -> bool {
 629        let mut cursor = self.transforms.cursor::<FoldPoint>();
 630        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 631        while let Some(transform) = cursor.item() {
 632            if transform.output_text.is_some() {
 633                return true;
 634            }
 635            if cursor.end(&()).row() == output_row {
 636                cursor.next(&())
 637            } else {
 638                break;
 639            }
 640        }
 641        false
 642    }
 643
 644    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 645        let start = start.to_offset(self);
 646        self.chunks(start..self.len(), false, None)
 647            .flat_map(|chunk| chunk.text.chars())
 648    }
 649
 650    pub fn chunks<'a>(
 651        &'a self,
 652        range: Range<FoldOffset>,
 653        language_aware: bool,
 654        text_highlights: Option<&'a TextHighlights>,
 655    ) -> FoldChunks<'a> {
 656        let mut highlight_endpoints = Vec::new();
 657        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 658
 659        let buffer_end = {
 660            transform_cursor.seek(&range.end, Bias::Right, &());
 661            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 662            transform_cursor.start().1 + overshoot
 663        };
 664
 665        let buffer_start = {
 666            transform_cursor.seek(&range.start, Bias::Right, &());
 667            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 668            transform_cursor.start().1 + overshoot
 669        };
 670
 671        if let Some(text_highlights) = text_highlights {
 672            if !text_highlights.is_empty() {
 673                while transform_cursor.start().0 < range.end {
 674                    if !transform_cursor.item().unwrap().is_fold() {
 675                        let transform_start = self
 676                            .buffer_snapshot
 677                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 678
 679                        let transform_end = {
 680                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 681                            self.buffer_snapshot.anchor_before(cmp::min(
 682                                transform_cursor.end(&()).1,
 683                                transform_cursor.start().1 + overshoot,
 684                            ))
 685                        };
 686
 687                        for (tag, highlights) in text_highlights.iter() {
 688                            let style = highlights.0;
 689                            let ranges = &highlights.1;
 690
 691                            let start_ix = match ranges.binary_search_by(|probe| {
 692                                let cmp = probe.end.cmp(&transform_start, &self.buffer_snapshot());
 693                                if cmp.is_gt() {
 694                                    Ordering::Greater
 695                                } else {
 696                                    Ordering::Less
 697                                }
 698                            }) {
 699                                Ok(i) | Err(i) => i,
 700                            };
 701                            for range in &ranges[start_ix..] {
 702                                if range
 703                                    .start
 704                                    .cmp(&transform_end, &self.buffer_snapshot)
 705                                    .is_ge()
 706                                {
 707                                    break;
 708                                }
 709
 710                                highlight_endpoints.push(HighlightEndpoint {
 711                                    offset: range.start.to_offset(&self.buffer_snapshot),
 712                                    is_start: true,
 713                                    tag: *tag,
 714                                    style,
 715                                });
 716                                highlight_endpoints.push(HighlightEndpoint {
 717                                    offset: range.end.to_offset(&self.buffer_snapshot),
 718                                    is_start: false,
 719                                    tag: *tag,
 720                                    style,
 721                                });
 722                            }
 723                        }
 724                    }
 725
 726                    transform_cursor.next(&());
 727                }
 728                highlight_endpoints.sort();
 729                transform_cursor.seek(&range.start, Bias::Right, &());
 730            }
 731        }
 732
 733        FoldChunks {
 734            transform_cursor,
 735            buffer_chunks: self
 736                .buffer_snapshot
 737                .chunks(buffer_start..buffer_end, language_aware),
 738            buffer_chunk: None,
 739            buffer_offset: buffer_start,
 740            output_offset: range.start.0,
 741            max_output_offset: range.end.0,
 742            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 743            active_highlights: Default::default(),
 744        }
 745    }
 746
 747    #[cfg(test)]
 748    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 749        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 750        cursor.seek(&offset, Bias::Right, &());
 751        if let Some(transform) = cursor.item() {
 752            let transform_start = cursor.start().0 .0;
 753            if transform.output_text.is_some() {
 754                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 755                    FoldOffset(transform_start)
 756                } else {
 757                    FoldOffset(cursor.end(&()).0 .0)
 758                }
 759            } else {
 760                let overshoot = offset.0 - transform_start;
 761                let buffer_offset = cursor.start().1 + overshoot;
 762                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 763                FoldOffset(
 764                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 765                        as usize,
 766                )
 767            }
 768        } else {
 769            FoldOffset(self.transforms.summary().output.bytes)
 770        }
 771    }
 772
 773    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 774        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 775        cursor.seek(&point, Bias::Right, &());
 776        if let Some(transform) = cursor.item() {
 777            let transform_start = cursor.start().0 .0;
 778            if transform.output_text.is_some() {
 779                if point.0 == transform_start || matches!(bias, Bias::Left) {
 780                    FoldPoint(transform_start)
 781                } else {
 782                    FoldPoint(cursor.end(&()).0 .0)
 783                }
 784            } else {
 785                let overshoot = point.0 - transform_start;
 786                let buffer_position = cursor.start().1 + overshoot;
 787                let clipped_buffer_position =
 788                    self.buffer_snapshot.clip_point(buffer_position, bias);
 789                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 790            }
 791        } else {
 792            FoldPoint(self.transforms.summary().output.lines)
 793        }
 794    }
 795}
 796
 797fn intersecting_folds<'a, T>(
 798    buffer: &'a MultiBufferSnapshot,
 799    folds: &'a SumTree<Fold>,
 800    range: Range<T>,
 801    inclusive: bool,
 802) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 803where
 804    T: ToOffset,
 805{
 806    let start = buffer.anchor_before(range.start.to_offset(buffer));
 807    let end = buffer.anchor_after(range.end.to_offset(buffer));
 808    let mut cursor = folds.filter::<_, usize>(move |summary| {
 809        let start_cmp = start.cmp(&summary.max_end, buffer);
 810        let end_cmp = end.cmp(&summary.min_start, buffer);
 811
 812        if inclusive {
 813            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 814        } else {
 815            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 816        }
 817    });
 818    cursor.next(buffer);
 819    cursor
 820}
 821
 822fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 823    edits.sort_unstable_by(|a, b| {
 824        a.old
 825            .start
 826            .cmp(&b.old.start)
 827            .then_with(|| b.old.end.cmp(&a.old.end))
 828    });
 829
 830    let mut i = 1;
 831    while i < edits.len() {
 832        let edit = edits[i].clone();
 833        let prev_edit = &mut edits[i - 1];
 834        if prev_edit.old.end >= edit.old.start {
 835            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 836            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 837            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 838            edits.remove(i);
 839            continue;
 840        }
 841        i += 1;
 842    }
 843}
 844
 845fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 846    edits.sort_unstable_by(|a, b| {
 847        a.old
 848            .start
 849            .cmp(&b.old.start)
 850            .then_with(|| b.old.end.cmp(&a.old.end))
 851    });
 852
 853    let mut i = 1;
 854    while i < edits.len() {
 855        let edit = edits[i].clone();
 856        let prev_edit = &mut edits[i - 1];
 857        if prev_edit.old.end >= edit.old.start {
 858            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 859            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 860            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 861            edits.remove(i);
 862            continue;
 863        }
 864        i += 1;
 865    }
 866}
 867
 868#[derive(Clone, Debug, Default, Eq, PartialEq)]
 869struct Transform {
 870    summary: TransformSummary,
 871    output_text: Option<&'static str>,
 872}
 873
 874impl Transform {
 875    fn is_fold(&self) -> bool {
 876        self.output_text.is_some()
 877    }
 878}
 879
 880#[derive(Clone, Debug, Default, Eq, PartialEq)]
 881struct TransformSummary {
 882    output: TextSummary,
 883    input: TextSummary,
 884}
 885
 886impl sum_tree::Item for Transform {
 887    type Summary = TransformSummary;
 888
 889    fn summary(&self) -> Self::Summary {
 890        self.summary.clone()
 891    }
 892}
 893
 894impl sum_tree::Summary for TransformSummary {
 895    type Context = ();
 896
 897    fn add_summary(&mut self, other: &Self, _: &()) {
 898        self.input += &other.input;
 899        self.output += &other.output;
 900    }
 901}
 902
 903#[derive(Clone, Debug)]
 904struct Fold(Range<Anchor>);
 905
 906impl Default for Fold {
 907    fn default() -> Self {
 908        Self(Anchor::min()..Anchor::max())
 909    }
 910}
 911
 912impl sum_tree::Item for Fold {
 913    type Summary = FoldSummary;
 914
 915    fn summary(&self) -> Self::Summary {
 916        FoldSummary {
 917            start: self.0.start.clone(),
 918            end: self.0.end.clone(),
 919            min_start: self.0.start.clone(),
 920            max_end: self.0.end.clone(),
 921            count: 1,
 922        }
 923    }
 924}
 925
 926#[derive(Clone, Debug)]
 927struct FoldSummary {
 928    start: Anchor,
 929    end: Anchor,
 930    min_start: Anchor,
 931    max_end: Anchor,
 932    count: usize,
 933}
 934
 935impl Default for FoldSummary {
 936    fn default() -> Self {
 937        Self {
 938            start: Anchor::min(),
 939            end: Anchor::max(),
 940            min_start: Anchor::max(),
 941            max_end: Anchor::min(),
 942            count: 0,
 943        }
 944    }
 945}
 946
 947impl sum_tree::Summary for FoldSummary {
 948    type Context = MultiBufferSnapshot;
 949
 950    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 951        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
 952            self.min_start = other.min_start.clone();
 953        }
 954        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
 955            self.max_end = other.max_end.clone();
 956        }
 957
 958        #[cfg(debug_assertions)]
 959        {
 960            let start_comparison = self.start.cmp(&other.start, buffer);
 961            assert!(start_comparison <= Ordering::Equal);
 962            if start_comparison == Ordering::Equal {
 963                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
 964            }
 965        }
 966
 967        self.start = other.start.clone();
 968        self.end = other.end.clone();
 969        self.count += other.count;
 970    }
 971}
 972
 973impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 974    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 975        self.0.start = summary.start.clone();
 976        self.0.end = summary.end.clone();
 977    }
 978}
 979
 980impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 981    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 982        self.0.cmp(&other.0, buffer)
 983    }
 984}
 985
 986impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 987    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 988        *self += summary.count;
 989    }
 990}
 991
 992pub struct FoldBufferRows<'a> {
 993    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 994    input_buffer_rows: MultiBufferRows<'a>,
 995    fold_point: FoldPoint,
 996}
 997
 998impl<'a> Iterator for FoldBufferRows<'a> {
 999    type Item = Option<u32>;
1000
1001    fn next(&mut self) -> Option<Self::Item> {
1002        let mut traversed_fold = false;
1003        while self.fold_point > self.cursor.end(&()).0 {
1004            self.cursor.next(&());
1005            traversed_fold = true;
1006            if self.cursor.item().is_none() {
1007                break;
1008            }
1009        }
1010
1011        if self.cursor.item().is_some() {
1012            if traversed_fold {
1013                self.input_buffer_rows.seek(self.cursor.start().1.row);
1014                self.input_buffer_rows.next();
1015            }
1016            *self.fold_point.row_mut() += 1;
1017            self.input_buffer_rows.next()
1018        } else {
1019            None
1020        }
1021    }
1022}
1023
1024pub struct FoldChunks<'a> {
1025    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1026    buffer_chunks: MultiBufferChunks<'a>,
1027    buffer_chunk: Option<(usize, Chunk<'a>)>,
1028    buffer_offset: usize,
1029    output_offset: usize,
1030    max_output_offset: usize,
1031    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1032    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1033}
1034
1035impl<'a> Iterator for FoldChunks<'a> {
1036    type Item = Chunk<'a>;
1037
1038    fn next(&mut self) -> Option<Self::Item> {
1039        if self.output_offset >= self.max_output_offset {
1040            return None;
1041        }
1042
1043        let transform = if let Some(item) = self.transform_cursor.item() {
1044            item
1045        } else {
1046            return None;
1047        };
1048
1049        // If we're in a fold, then return the fold's display text and
1050        // advance the transform and buffer cursors to the end of the fold.
1051        if let Some(output_text) = transform.output_text {
1052            self.buffer_chunk.take();
1053            self.buffer_offset += transform.summary.input.bytes;
1054            self.buffer_chunks.seek(self.buffer_offset);
1055
1056            while self.buffer_offset >= self.transform_cursor.end(&()).1
1057                && self.transform_cursor.item().is_some()
1058            {
1059                self.transform_cursor.next(&());
1060            }
1061
1062            self.output_offset += output_text.len();
1063            return Some(Chunk {
1064                text: output_text,
1065                syntax_highlight_id: None,
1066                highlight_style: None,
1067                diagnostic_severity: None,
1068                is_unnecessary: false,
1069            });
1070        }
1071
1072        let mut next_highlight_endpoint = usize::MAX;
1073        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1074            if endpoint.offset <= self.buffer_offset {
1075                if endpoint.is_start {
1076                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1077                } else {
1078                    self.active_highlights.remove(&endpoint.tag);
1079                }
1080                self.highlight_endpoints.next();
1081            } else {
1082                next_highlight_endpoint = endpoint.offset;
1083                break;
1084            }
1085        }
1086
1087        // Retrieve a chunk from the current location in the buffer.
1088        if self.buffer_chunk.is_none() {
1089            let chunk_offset = self.buffer_chunks.offset();
1090            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1091        }
1092
1093        // Otherwise, take a chunk from the buffer's text.
1094        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1095            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1096            let transform_end = self.transform_cursor.end(&()).1;
1097            let chunk_end = buffer_chunk_end
1098                .min(transform_end)
1099                .min(next_highlight_endpoint);
1100
1101            chunk.text = &chunk.text
1102                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1103
1104            if !self.active_highlights.is_empty() {
1105                let mut highlight_style = HighlightStyle::default();
1106                for active_highlight in self.active_highlights.values() {
1107                    highlight_style.highlight(*active_highlight);
1108                }
1109                chunk.highlight_style = Some(highlight_style);
1110            }
1111
1112            if chunk_end == transform_end {
1113                self.transform_cursor.next(&());
1114            } else if chunk_end == buffer_chunk_end {
1115                self.buffer_chunk.take();
1116            }
1117
1118            self.buffer_offset = chunk_end;
1119            self.output_offset += chunk.text.len();
1120            return Some(chunk);
1121        }
1122
1123        None
1124    }
1125}
1126
1127#[derive(Copy, Clone, Eq, PartialEq)]
1128struct HighlightEndpoint {
1129    offset: usize,
1130    is_start: bool,
1131    tag: Option<TypeId>,
1132    style: HighlightStyle,
1133}
1134
1135impl PartialOrd for HighlightEndpoint {
1136    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1137        Some(self.cmp(other))
1138    }
1139}
1140
1141impl Ord for HighlightEndpoint {
1142    fn cmp(&self, other: &Self) -> Ordering {
1143        self.offset
1144            .cmp(&other.offset)
1145            .then_with(|| other.is_start.cmp(&self.is_start))
1146    }
1147}
1148
1149#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1150pub struct FoldOffset(pub usize);
1151
1152impl FoldOffset {
1153    pub fn to_point(&self, snapshot: &FoldSnapshot) -> FoldPoint {
1154        let mut cursor = snapshot
1155            .transforms
1156            .cursor::<(FoldOffset, TransformSummary)>();
1157        cursor.seek(self, Bias::Right, &());
1158        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1159            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1160        } else {
1161            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1162            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1163            buffer_point - cursor.start().1.input.lines
1164        };
1165        FoldPoint(cursor.start().1.output.lines + overshoot)
1166    }
1167}
1168
1169impl Sub for FoldOffset {
1170    type Output = Self;
1171
1172    fn sub(self, rhs: Self) -> Self::Output {
1173        Self(self.0 - rhs.0)
1174    }
1175}
1176
1177impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1178    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1179        self.0 += &summary.output.bytes;
1180    }
1181}
1182
1183impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1184    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1185        *self += &summary.input.lines;
1186    }
1187}
1188
1189impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1190    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1191        *self += &summary.input.bytes;
1192    }
1193}
1194
1195pub type FoldEdit = Edit<FoldOffset>;
1196
1197#[cfg(test)]
1198mod tests {
1199    use super::*;
1200    use crate::{MultiBuffer, ToPoint};
1201    use rand::prelude::*;
1202    use settings::Settings;
1203    use std::{cmp::Reverse, env, mem, sync::Arc};
1204    use sum_tree::TreeMap;
1205    use text::RandomCharIter;
1206    use util::test::sample_text;
1207    use Bias::{Left, Right};
1208
1209    #[gpui::test]
1210    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1211        cx.set_global(Settings::test(cx));
1212        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1213        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1214        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1215        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1216
1217        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1218        let (snapshot2, edits) = writer.fold(vec![
1219            Point::new(0, 2)..Point::new(2, 2),
1220            Point::new(2, 4)..Point::new(4, 1),
1221        ]);
1222        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1223        assert_eq!(
1224            edits,
1225            &[
1226                FoldEdit {
1227                    old: FoldOffset(2)..FoldOffset(16),
1228                    new: FoldOffset(2)..FoldOffset(5),
1229                },
1230                FoldEdit {
1231                    old: FoldOffset(18)..FoldOffset(29),
1232                    new: FoldOffset(7)..FoldOffset(10)
1233                },
1234            ]
1235        );
1236
1237        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1238            buffer.edit(
1239                vec![
1240                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1241                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1242                ],
1243                cx,
1244            );
1245            buffer.snapshot(cx)
1246        });
1247        let (snapshot3, edits) =
1248            map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1249        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1250        assert_eq!(
1251            edits,
1252            &[
1253                FoldEdit {
1254                    old: FoldOffset(0)..FoldOffset(1),
1255                    new: FoldOffset(0)..FoldOffset(3),
1256                },
1257                FoldEdit {
1258                    old: FoldOffset(6)..FoldOffset(6),
1259                    new: FoldOffset(8)..FoldOffset(11),
1260                },
1261            ]
1262        );
1263
1264        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1265            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], cx);
1266            buffer.snapshot(cx)
1267        });
1268        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1269        assert_eq!(snapshot4.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)), false);
1273        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1274        assert_eq!(snapshot5.text(), "123a…c123456eee");
1275
1276        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1277        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1278        let (snapshot6, _) = map.read(buffer_snapshot.clone(), vec![]);
1279        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1280    }
1281
1282    #[gpui::test]
1283    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1284        cx.set_global(Settings::test(cx));
1285        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1286        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1287        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1288
1289        {
1290            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1291
1292            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1293            writer.fold(vec![5..8]);
1294            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1295            assert_eq!(snapshot.text(), "abcde…ijkl");
1296
1297            // Create an fold adjacent to the start of the first fold.
1298            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1299            writer.fold(vec![0..1, 2..5]);
1300            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1301            assert_eq!(snapshot.text(), "…b…ijkl");
1302
1303            // Create an fold adjacent to the end of the first fold.
1304            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1305            writer.fold(vec![11..11, 8..10]);
1306            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1307            assert_eq!(snapshot.text(), "…b…kl");
1308        }
1309
1310        {
1311            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1312
1313            // Create two adjacent folds.
1314            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1315            writer.fold(vec![0..2, 2..5]);
1316            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1317            assert_eq!(snapshot.text(), "…fghijkl");
1318
1319            // Edit within one of the folds.
1320            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1321                buffer.edit([(0..1, "12345")], cx);
1322                buffer.snapshot(cx)
1323            });
1324            let (snapshot, _) =
1325                map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1326            assert_eq!(snapshot.text(), "12345…fghijkl");
1327        }
1328    }
1329
1330    #[gpui::test]
1331    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1332        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1333        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1334        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1335        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1336        writer.fold(vec![
1337            Point::new(0, 2)..Point::new(2, 2),
1338            Point::new(0, 4)..Point::new(1, 0),
1339            Point::new(1, 2)..Point::new(3, 2),
1340            Point::new(3, 1)..Point::new(4, 1),
1341        ]);
1342        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1343        assert_eq!(snapshot.text(), "aa…eeeee");
1344    }
1345
1346    #[gpui::test]
1347    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1348        cx.set_global(Settings::test(cx));
1349        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1350        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1351        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1352        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1353
1354        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1355        writer.fold(vec![
1356            Point::new(0, 2)..Point::new(2, 2),
1357            Point::new(3, 1)..Point::new(4, 1),
1358        ]);
1359        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1360        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1361
1362        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1363            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], cx);
1364            buffer.snapshot(cx)
1365        });
1366        let (snapshot, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1367        assert_eq!(snapshot.text(), "aa…eeeee");
1368    }
1369
1370    #[gpui::test]
1371    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1372        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1373        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1374        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1375
1376        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1377        writer.fold(vec![
1378            Point::new(0, 2)..Point::new(2, 2),
1379            Point::new(0, 4)..Point::new(1, 0),
1380            Point::new(1, 2)..Point::new(3, 2),
1381            Point::new(3, 1)..Point::new(4, 1),
1382        ]);
1383        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1384        let fold_ranges = snapshot
1385            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1386            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1387            .collect::<Vec<_>>();
1388        assert_eq!(
1389            fold_ranges,
1390            vec![
1391                Point::new(0, 2)..Point::new(2, 2),
1392                Point::new(1, 2)..Point::new(3, 2)
1393            ]
1394        );
1395    }
1396
1397    #[gpui::test(iterations = 100)]
1398    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1399        cx.set_global(Settings::test(cx));
1400        let operations = env::var("OPERATIONS")
1401            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1402            .unwrap_or(10);
1403
1404        let len = rng.gen_range(0..10);
1405        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1406        let buffer = if rng.gen() {
1407            MultiBuffer::build_simple(&text, cx)
1408        } else {
1409            MultiBuffer::build_random(&mut rng, cx)
1410        };
1411        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1412        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1413
1414        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1415        let mut snapshot_edits = Vec::new();
1416
1417        let mut highlights = TreeMap::default();
1418        let highlight_count = rng.gen_range(0_usize..10);
1419        let mut highlight_ranges = (0..highlight_count)
1420            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1421            .collect::<Vec<_>>();
1422        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1423        log::info!("highlighting ranges {:?}", highlight_ranges);
1424        let highlight_ranges = highlight_ranges
1425            .into_iter()
1426            .map(|range| {
1427                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1428            })
1429            .collect::<Vec<_>>();
1430
1431        highlights.insert(
1432            Some(TypeId::of::<()>()),
1433            Arc::new((HighlightStyle::default(), highlight_ranges)),
1434        );
1435
1436        for _ in 0..operations {
1437            log::info!("text: {:?}", buffer_snapshot.text());
1438            let mut buffer_edits = Vec::new();
1439            match rng.gen_range(0..=100) {
1440                0..=59 => {
1441                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1442                }
1443                _ => buffer.update(cx, |buffer, cx| {
1444                    let subscription = buffer.subscribe();
1445                    let edit_count = rng.gen_range(1..=5);
1446                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1447                    buffer_snapshot = buffer.snapshot(cx);
1448                    let edits = subscription.consume().into_inner();
1449                    log::info!("editing {:?}", edits);
1450                    buffer_edits.extend(edits);
1451                }),
1452            };
1453
1454            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1455            snapshot_edits.push((snapshot.clone(), edits));
1456
1457            let mut expected_text: String = buffer_snapshot.text().to_string();
1458            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1459                expected_text.replace_range(fold_range.start..fold_range.end, "…");
1460            }
1461
1462            assert_eq!(snapshot.text(), expected_text);
1463            log::info!(
1464                "fold text {:?} ({} lines)",
1465                expected_text,
1466                expected_text.matches('\n').count() + 1
1467            );
1468
1469            let mut prev_row = 0;
1470            let mut expected_buffer_rows = Vec::new();
1471            for fold_range in map.merged_fold_ranges().into_iter() {
1472                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1473                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1474                expected_buffer_rows.extend(
1475                    buffer_snapshot
1476                        .buffer_rows(prev_row)
1477                        .take((1 + fold_start - prev_row) as usize),
1478                );
1479                prev_row = 1 + fold_end;
1480            }
1481            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1482
1483            assert_eq!(
1484                expected_buffer_rows.len(),
1485                expected_text.matches('\n').count() + 1,
1486                "wrong expected buffer rows {:?}. text: {:?}",
1487                expected_buffer_rows,
1488                expected_text
1489            );
1490
1491            for (output_row, line) in expected_text.lines().enumerate() {
1492                let line_len = snapshot.line_len(output_row as u32);
1493                assert_eq!(line_len, line.len() as u32);
1494            }
1495
1496            let longest_row = snapshot.longest_row();
1497            let longest_char_column = expected_text
1498                .split('\n')
1499                .nth(longest_row as usize)
1500                .unwrap()
1501                .chars()
1502                .count();
1503            let mut fold_point = FoldPoint::new(0, 0);
1504            let mut fold_offset = FoldOffset(0);
1505            let mut char_column = 0;
1506            for c in expected_text.chars() {
1507                let buffer_point = fold_point.to_buffer_point(&snapshot);
1508                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1509                assert_eq!(
1510                    snapshot.to_fold_point(buffer_point, Right),
1511                    fold_point,
1512                    "{:?} -> fold point",
1513                    buffer_point,
1514                );
1515                assert_eq!(
1516                    fold_point.to_buffer_offset(&snapshot),
1517                    buffer_offset,
1518                    "fold_point.to_buffer_offset({:?})",
1519                    fold_point,
1520                );
1521                assert_eq!(
1522                    fold_point.to_offset(&snapshot),
1523                    fold_offset,
1524                    "fold_point.to_offset({:?})",
1525                    fold_point,
1526                );
1527
1528                if c == '\n' {
1529                    *fold_point.row_mut() += 1;
1530                    *fold_point.column_mut() = 0;
1531                    char_column = 0;
1532                } else {
1533                    *fold_point.column_mut() += c.len_utf8() as u32;
1534                    char_column += 1;
1535                }
1536                fold_offset.0 += c.len_utf8();
1537                if char_column > longest_char_column {
1538                    panic!(
1539                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1540                        longest_row,
1541                        longest_char_column,
1542                        fold_point.row(),
1543                        char_column
1544                    );
1545                }
1546            }
1547
1548            for _ in 0..5 {
1549                let mut start = snapshot
1550                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1551                let mut end = snapshot
1552                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1553                if start > end {
1554                    mem::swap(&mut start, &mut end);
1555                }
1556
1557                let text = &expected_text[start.0..end.0];
1558                assert_eq!(
1559                    snapshot
1560                        .chunks(start..end, false, Some(&highlights))
1561                        .map(|c| c.text)
1562                        .collect::<String>(),
1563                    text,
1564                );
1565            }
1566
1567            let mut fold_row = 0;
1568            while fold_row < expected_buffer_rows.len() as u32 {
1569                fold_row = snapshot
1570                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1571                    .row();
1572                assert_eq!(
1573                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1574                    expected_buffer_rows[(fold_row as usize)..],
1575                    "wrong buffer rows starting at fold row {}",
1576                    fold_row,
1577                );
1578                fold_row += 1;
1579            }
1580
1581            for fold_range in map.merged_fold_ranges() {
1582                let fold_point =
1583                    snapshot.to_fold_point(fold_range.start.to_point(&buffer_snapshot), Right);
1584                assert!(snapshot.is_line_folded(fold_point.row()));
1585            }
1586
1587            for _ in 0..5 {
1588                let end =
1589                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1590                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1591                let expected_folds = map
1592                    .folds
1593                    .items(&buffer_snapshot)
1594                    .into_iter()
1595                    .filter(|fold| {
1596                        let start = buffer_snapshot.anchor_before(start);
1597                        let end = buffer_snapshot.anchor_after(end);
1598                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1599                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1600                    })
1601                    .map(|fold| fold.0)
1602                    .collect::<Vec<_>>();
1603
1604                assert_eq!(
1605                    snapshot
1606                        .folds_in_range(start..end)
1607                        .cloned()
1608                        .collect::<Vec<_>>(),
1609                    expected_folds
1610                );
1611            }
1612
1613            let text = snapshot.text();
1614            for _ in 0..5 {
1615                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1616                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1617                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1618                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1619                let mut start =
1620                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1621                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1622                if start > end {
1623                    mem::swap(&mut start, &mut end);
1624                }
1625
1626                let lines = start..end;
1627                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1628                assert_eq!(
1629                    snapshot.text_summary_for_range(lines),
1630                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1631                )
1632            }
1633
1634            let mut text = initial_snapshot.text();
1635            for (snapshot, edits) in snapshot_edits.drain(..) {
1636                let new_text = snapshot.text();
1637                for edit in edits {
1638                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1639                    let new_bytes = edit.new.start.0..edit.new.end.0;
1640                    text.replace_range(old_bytes, &new_text[new_bytes]);
1641                }
1642
1643                assert_eq!(text, new_text);
1644                initial_snapshot = snapshot;
1645            }
1646        }
1647    }
1648
1649    #[gpui::test]
1650    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1651        let text = sample_text(6, 6, 'a') + "\n";
1652        let buffer = MultiBuffer::build_simple(&text, cx);
1653
1654        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1655        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1656
1657        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1658        writer.fold(vec![
1659            Point::new(0, 2)..Point::new(2, 2),
1660            Point::new(3, 1)..Point::new(4, 1),
1661        ]);
1662
1663        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1664        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1665        assert_eq!(
1666            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1667            [Some(0), Some(3), Some(5), Some(6)]
1668        );
1669        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1670    }
1671
1672    impl FoldMap {
1673        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1674            let buffer = self.buffer.lock().clone();
1675            let mut folds = self.folds.items(&buffer);
1676            // Ensure sorting doesn't change how folds get merged and displayed.
1677            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer));
1678            let mut fold_ranges = folds
1679                .iter()
1680                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1681                .peekable();
1682
1683            let mut merged_ranges = Vec::new();
1684            while let Some(mut fold_range) = fold_ranges.next() {
1685                while let Some(next_range) = fold_ranges.peek() {
1686                    if fold_range.end >= next_range.start {
1687                        if next_range.end > fold_range.end {
1688                            fold_range.end = next_range.end;
1689                        }
1690                        fold_ranges.next();
1691                    } else {
1692                        break;
1693                    }
1694                }
1695                if fold_range.end > fold_range.start {
1696                    merged_ranges.push(fold_range);
1697                }
1698            }
1699            merged_ranges
1700        }
1701
1702        pub fn randomly_mutate(
1703            &mut self,
1704            rng: &mut impl Rng,
1705        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1706            let mut snapshot_edits = Vec::new();
1707            match rng.gen_range(0..=100) {
1708                0..=39 if !self.folds.is_empty() => {
1709                    let buffer = self.buffer.lock().clone();
1710                    let mut to_unfold = Vec::new();
1711                    for _ in 0..rng.gen_range(1..=3) {
1712                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1713                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1714                        to_unfold.push(start..end);
1715                    }
1716                    log::info!("unfolding {:?}", to_unfold);
1717                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1718                    snapshot_edits.push((snapshot, edits));
1719                    let (snapshot, edits) = writer.fold(to_unfold);
1720                    snapshot_edits.push((snapshot, edits));
1721                }
1722                _ => {
1723                    let buffer = self.buffer.lock().clone();
1724                    let mut to_fold = Vec::new();
1725                    for _ in 0..rng.gen_range(1..=2) {
1726                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1727                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1728                        to_fold.push(start..end);
1729                    }
1730                    log::info!("folding {:?}", to_fold);
1731                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1732                    snapshot_edits.push((snapshot, edits));
1733                    let (snapshot, edits) = writer.fold(to_fold);
1734                    snapshot_edits.push((snapshot, edits));
1735                }
1736            }
1737            snapshot_edits
1738        }
1739    }
1740}