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.len;
  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.len;
  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.len,
 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.len);
 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.len {
 357                        let text_summary = new_buffer
 358                            .text_summary_for_range::<TextSummary, _>(sum.input.len..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.len < edit.new.end {
 388                    let text_summary = new_buffer
 389                        .text_summary_for_range::<TextSummary, _>(sum.input.len..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.len)
 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<T>(&self, range: Range<T>) -> impl Iterator<Item = &Range<Anchor>>
 604    where
 605        T: ToOffset,
 606    {
 607        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 608        iter::from_fn(move || {
 609            let item = folds.item().map(|f| &f.0);
 610            folds.next(&self.buffer_snapshot);
 611            item
 612        })
 613    }
 614
 615    pub fn intersects_fold<T>(&self, offset: T) -> bool
 616    where
 617        T: ToOffset,
 618    {
 619        let offset = offset.to_offset(&self.buffer_snapshot);
 620        let mut cursor = self.transforms.cursor::<usize>();
 621        cursor.seek(&offset, Bias::Right, &());
 622        cursor.item().map_or(false, |t| t.output_text.is_some())
 623    }
 624
 625    pub fn is_line_folded(&self, output_row: u32) -> bool {
 626        let mut cursor = self.transforms.cursor::<FoldPoint>();
 627        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 628        while let Some(transform) = cursor.item() {
 629            if transform.output_text.is_some() {
 630                return true;
 631            }
 632            if cursor.end(&()).row() == output_row {
 633                cursor.next(&())
 634            } else {
 635                break;
 636            }
 637        }
 638        false
 639    }
 640
 641    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 642        let start = start.to_offset(self);
 643        self.chunks(start..self.len(), false, None)
 644            .flat_map(|chunk| chunk.text.chars())
 645    }
 646
 647    pub fn chunks<'a>(
 648        &'a self,
 649        range: Range<FoldOffset>,
 650        language_aware: bool,
 651        text_highlights: Option<&'a TextHighlights>,
 652    ) -> FoldChunks<'a> {
 653        let mut highlight_endpoints = Vec::new();
 654        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 655
 656        let buffer_end = {
 657            transform_cursor.seek(&range.end, Bias::Right, &());
 658            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 659            transform_cursor.start().1 + overshoot
 660        };
 661
 662        let buffer_start = {
 663            transform_cursor.seek(&range.start, Bias::Right, &());
 664            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 665            transform_cursor.start().1 + overshoot
 666        };
 667
 668        if let Some(text_highlights) = text_highlights {
 669            if !text_highlights.is_empty() {
 670                while transform_cursor.start().0 < range.end {
 671                    if !transform_cursor.item().unwrap().is_fold() {
 672                        let transform_start = self
 673                            .buffer_snapshot
 674                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 675
 676                        let transform_end = {
 677                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 678                            self.buffer_snapshot.anchor_before(cmp::min(
 679                                transform_cursor.end(&()).1,
 680                                transform_cursor.start().1 + overshoot,
 681                            ))
 682                        };
 683
 684                        for (tag, highlights) in text_highlights.iter() {
 685                            let style = highlights.0;
 686                            let ranges = &highlights.1;
 687
 688                            let start_ix = match ranges.binary_search_by(|probe| {
 689                                let cmp = probe.end.cmp(&transform_start, self.buffer_snapshot());
 690                                if cmp.is_gt() {
 691                                    Ordering::Greater
 692                                } else {
 693                                    Ordering::Less
 694                                }
 695                            }) {
 696                                Ok(i) | Err(i) => i,
 697                            };
 698                            for range in &ranges[start_ix..] {
 699                                if range
 700                                    .start
 701                                    .cmp(&transform_end, &self.buffer_snapshot)
 702                                    .is_ge()
 703                                {
 704                                    break;
 705                                }
 706
 707                                highlight_endpoints.push(HighlightEndpoint {
 708                                    offset: range.start.to_offset(&self.buffer_snapshot),
 709                                    is_start: true,
 710                                    tag: *tag,
 711                                    style,
 712                                });
 713                                highlight_endpoints.push(HighlightEndpoint {
 714                                    offset: range.end.to_offset(&self.buffer_snapshot),
 715                                    is_start: false,
 716                                    tag: *tag,
 717                                    style,
 718                                });
 719                            }
 720                        }
 721                    }
 722
 723                    transform_cursor.next(&());
 724                }
 725                highlight_endpoints.sort();
 726                transform_cursor.seek(&range.start, Bias::Right, &());
 727            }
 728        }
 729
 730        FoldChunks {
 731            transform_cursor,
 732            buffer_chunks: self
 733                .buffer_snapshot
 734                .chunks(buffer_start..buffer_end, language_aware),
 735            buffer_chunk: None,
 736            buffer_offset: buffer_start,
 737            output_offset: range.start.0,
 738            max_output_offset: range.end.0,
 739            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 740            active_highlights: Default::default(),
 741        }
 742    }
 743
 744    #[cfg(test)]
 745    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 746        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 747        cursor.seek(&offset, Bias::Right, &());
 748        if let Some(transform) = cursor.item() {
 749            let transform_start = cursor.start().0 .0;
 750            if transform.output_text.is_some() {
 751                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 752                    FoldOffset(transform_start)
 753                } else {
 754                    FoldOffset(cursor.end(&()).0 .0)
 755                }
 756            } else {
 757                let overshoot = offset.0 - transform_start;
 758                let buffer_offset = cursor.start().1 + overshoot;
 759                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 760                FoldOffset(
 761                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 762                        as usize,
 763                )
 764            }
 765        } else {
 766            FoldOffset(self.transforms.summary().output.len)
 767        }
 768    }
 769
 770    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 771        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 772        cursor.seek(&point, Bias::Right, &());
 773        if let Some(transform) = cursor.item() {
 774            let transform_start = cursor.start().0 .0;
 775            if transform.output_text.is_some() {
 776                if point.0 == transform_start || matches!(bias, Bias::Left) {
 777                    FoldPoint(transform_start)
 778                } else {
 779                    FoldPoint(cursor.end(&()).0 .0)
 780                }
 781            } else {
 782                let overshoot = point.0 - transform_start;
 783                let buffer_position = cursor.start().1 + overshoot;
 784                let clipped_buffer_position =
 785                    self.buffer_snapshot.clip_point(buffer_position, bias);
 786                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 787            }
 788        } else {
 789            FoldPoint(self.transforms.summary().output.lines)
 790        }
 791    }
 792}
 793
 794fn intersecting_folds<'a, T>(
 795    buffer: &'a MultiBufferSnapshot,
 796    folds: &'a SumTree<Fold>,
 797    range: Range<T>,
 798    inclusive: bool,
 799) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 800where
 801    T: ToOffset,
 802{
 803    let start = buffer.anchor_before(range.start.to_offset(buffer));
 804    let end = buffer.anchor_after(range.end.to_offset(buffer));
 805    let mut cursor = folds.filter::<_, usize>(move |summary| {
 806        let start_cmp = start.cmp(&summary.max_end, buffer);
 807        let end_cmp = end.cmp(&summary.min_start, buffer);
 808
 809        if inclusive {
 810            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 811        } else {
 812            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 813        }
 814    });
 815    cursor.next(buffer);
 816    cursor
 817}
 818
 819fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 820    edits.sort_unstable_by(|a, b| {
 821        a.old
 822            .start
 823            .cmp(&b.old.start)
 824            .then_with(|| b.old.end.cmp(&a.old.end))
 825    });
 826
 827    let mut i = 1;
 828    while i < edits.len() {
 829        let edit = edits[i].clone();
 830        let prev_edit = &mut edits[i - 1];
 831        if prev_edit.old.end >= edit.old.start {
 832            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 833            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 834            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 835            edits.remove(i);
 836            continue;
 837        }
 838        i += 1;
 839    }
 840}
 841
 842fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 843    edits.sort_unstable_by(|a, b| {
 844        a.old
 845            .start
 846            .cmp(&b.old.start)
 847            .then_with(|| b.old.end.cmp(&a.old.end))
 848    });
 849
 850    let mut i = 1;
 851    while i < edits.len() {
 852        let edit = edits[i].clone();
 853        let prev_edit = &mut edits[i - 1];
 854        if prev_edit.old.end >= edit.old.start {
 855            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 856            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 857            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 858            edits.remove(i);
 859            continue;
 860        }
 861        i += 1;
 862    }
 863}
 864
 865#[derive(Clone, Debug, Default, Eq, PartialEq)]
 866struct Transform {
 867    summary: TransformSummary,
 868    output_text: Option<&'static str>,
 869}
 870
 871impl Transform {
 872    fn is_fold(&self) -> bool {
 873        self.output_text.is_some()
 874    }
 875}
 876
 877#[derive(Clone, Debug, Default, Eq, PartialEq)]
 878struct TransformSummary {
 879    output: TextSummary,
 880    input: TextSummary,
 881}
 882
 883impl sum_tree::Item for Transform {
 884    type Summary = TransformSummary;
 885
 886    fn summary(&self) -> Self::Summary {
 887        self.summary.clone()
 888    }
 889}
 890
 891impl sum_tree::Summary for TransformSummary {
 892    type Context = ();
 893
 894    fn add_summary(&mut self, other: &Self, _: &()) {
 895        self.input += &other.input;
 896        self.output += &other.output;
 897    }
 898}
 899
 900#[derive(Clone, Debug)]
 901struct Fold(Range<Anchor>);
 902
 903impl Default for Fold {
 904    fn default() -> Self {
 905        Self(Anchor::min()..Anchor::max())
 906    }
 907}
 908
 909impl sum_tree::Item for Fold {
 910    type Summary = FoldSummary;
 911
 912    fn summary(&self) -> Self::Summary {
 913        FoldSummary {
 914            start: self.0.start.clone(),
 915            end: self.0.end.clone(),
 916            min_start: self.0.start.clone(),
 917            max_end: self.0.end.clone(),
 918            count: 1,
 919        }
 920    }
 921}
 922
 923#[derive(Clone, Debug)]
 924struct FoldSummary {
 925    start: Anchor,
 926    end: Anchor,
 927    min_start: Anchor,
 928    max_end: Anchor,
 929    count: usize,
 930}
 931
 932impl Default for FoldSummary {
 933    fn default() -> Self {
 934        Self {
 935            start: Anchor::min(),
 936            end: Anchor::max(),
 937            min_start: Anchor::max(),
 938            max_end: Anchor::min(),
 939            count: 0,
 940        }
 941    }
 942}
 943
 944impl sum_tree::Summary for FoldSummary {
 945    type Context = MultiBufferSnapshot;
 946
 947    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 948        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
 949            self.min_start = other.min_start.clone();
 950        }
 951        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
 952            self.max_end = other.max_end.clone();
 953        }
 954
 955        #[cfg(debug_assertions)]
 956        {
 957            let start_comparison = self.start.cmp(&other.start, buffer);
 958            assert!(start_comparison <= Ordering::Equal);
 959            if start_comparison == Ordering::Equal {
 960                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
 961            }
 962        }
 963
 964        self.start = other.start.clone();
 965        self.end = other.end.clone();
 966        self.count += other.count;
 967    }
 968}
 969
 970impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 971    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 972        self.0.start = summary.start.clone();
 973        self.0.end = summary.end.clone();
 974    }
 975}
 976
 977impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 978    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 979        self.0.cmp(&other.0, buffer)
 980    }
 981}
 982
 983impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 984    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 985        *self += summary.count;
 986    }
 987}
 988
 989pub struct FoldBufferRows<'a> {
 990    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 991    input_buffer_rows: MultiBufferRows<'a>,
 992    fold_point: FoldPoint,
 993}
 994
 995impl<'a> Iterator for FoldBufferRows<'a> {
 996    type Item = Option<u32>;
 997
 998    fn next(&mut self) -> Option<Self::Item> {
 999        let mut traversed_fold = false;
1000        while self.fold_point > self.cursor.end(&()).0 {
1001            self.cursor.next(&());
1002            traversed_fold = true;
1003            if self.cursor.item().is_none() {
1004                break;
1005            }
1006        }
1007
1008        if self.cursor.item().is_some() {
1009            if traversed_fold {
1010                self.input_buffer_rows.seek(self.cursor.start().1.row);
1011                self.input_buffer_rows.next();
1012            }
1013            *self.fold_point.row_mut() += 1;
1014            self.input_buffer_rows.next()
1015        } else {
1016            None
1017        }
1018    }
1019}
1020
1021pub struct FoldChunks<'a> {
1022    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1023    buffer_chunks: MultiBufferChunks<'a>,
1024    buffer_chunk: Option<(usize, Chunk<'a>)>,
1025    buffer_offset: usize,
1026    output_offset: usize,
1027    max_output_offset: usize,
1028    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1029    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1030}
1031
1032impl<'a> Iterator for FoldChunks<'a> {
1033    type Item = Chunk<'a>;
1034
1035    fn next(&mut self) -> Option<Self::Item> {
1036        if self.output_offset >= self.max_output_offset {
1037            return None;
1038        }
1039
1040        let transform = self.transform_cursor.item()?;
1041
1042        // If we're in a fold, then return the fold's display text and
1043        // advance the transform and buffer cursors to the end of the fold.
1044        if let Some(output_text) = transform.output_text {
1045            self.buffer_chunk.take();
1046            self.buffer_offset += transform.summary.input.len;
1047            self.buffer_chunks.seek(self.buffer_offset);
1048
1049            while self.buffer_offset >= self.transform_cursor.end(&()).1
1050                && self.transform_cursor.item().is_some()
1051            {
1052                self.transform_cursor.next(&());
1053            }
1054
1055            self.output_offset += output_text.len();
1056            return Some(Chunk {
1057                text: output_text,
1058                syntax_highlight_id: None,
1059                highlight_style: None,
1060                diagnostic_severity: None,
1061                is_unnecessary: false,
1062            });
1063        }
1064
1065        let mut next_highlight_endpoint = usize::MAX;
1066        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1067            if endpoint.offset <= self.buffer_offset {
1068                if endpoint.is_start {
1069                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1070                } else {
1071                    self.active_highlights.remove(&endpoint.tag);
1072                }
1073                self.highlight_endpoints.next();
1074            } else {
1075                next_highlight_endpoint = endpoint.offset;
1076                break;
1077            }
1078        }
1079
1080        // Retrieve a chunk from the current location in the buffer.
1081        if self.buffer_chunk.is_none() {
1082            let chunk_offset = self.buffer_chunks.offset();
1083            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1084        }
1085
1086        // Otherwise, take a chunk from the buffer's text.
1087        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1088            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1089            let transform_end = self.transform_cursor.end(&()).1;
1090            let chunk_end = buffer_chunk_end
1091                .min(transform_end)
1092                .min(next_highlight_endpoint);
1093
1094            chunk.text = &chunk.text
1095                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1096
1097            if !self.active_highlights.is_empty() {
1098                let mut highlight_style = HighlightStyle::default();
1099                for active_highlight in self.active_highlights.values() {
1100                    highlight_style.highlight(*active_highlight);
1101                }
1102                chunk.highlight_style = Some(highlight_style);
1103            }
1104
1105            if chunk_end == transform_end {
1106                self.transform_cursor.next(&());
1107            } else if chunk_end == buffer_chunk_end {
1108                self.buffer_chunk.take();
1109            }
1110
1111            self.buffer_offset = chunk_end;
1112            self.output_offset += chunk.text.len();
1113            return Some(chunk);
1114        }
1115
1116        None
1117    }
1118}
1119
1120#[derive(Copy, Clone, Eq, PartialEq)]
1121struct HighlightEndpoint {
1122    offset: usize,
1123    is_start: bool,
1124    tag: Option<TypeId>,
1125    style: HighlightStyle,
1126}
1127
1128impl PartialOrd for HighlightEndpoint {
1129    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1130        Some(self.cmp(other))
1131    }
1132}
1133
1134impl Ord for HighlightEndpoint {
1135    fn cmp(&self, other: &Self) -> Ordering {
1136        self.offset
1137            .cmp(&other.offset)
1138            .then_with(|| other.is_start.cmp(&self.is_start))
1139    }
1140}
1141
1142#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1143pub struct FoldOffset(pub usize);
1144
1145impl FoldOffset {
1146    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1147        let mut cursor = snapshot
1148            .transforms
1149            .cursor::<(FoldOffset, TransformSummary)>();
1150        cursor.seek(&self, Bias::Right, &());
1151        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1152            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1153        } else {
1154            let buffer_offset = cursor.start().1.input.len + self.0 - cursor.start().0 .0;
1155            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1156            buffer_point - cursor.start().1.input.lines
1157        };
1158        FoldPoint(cursor.start().1.output.lines + overshoot)
1159    }
1160}
1161
1162impl Sub for FoldOffset {
1163    type Output = Self;
1164
1165    fn sub(self, rhs: Self) -> Self::Output {
1166        Self(self.0 - rhs.0)
1167    }
1168}
1169
1170impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1171    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1172        self.0 += &summary.output.len;
1173    }
1174}
1175
1176impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1177    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1178        *self += &summary.input.lines;
1179    }
1180}
1181
1182impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1183    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1184        *self += &summary.input.len;
1185    }
1186}
1187
1188pub type FoldEdit = Edit<FoldOffset>;
1189
1190#[cfg(test)]
1191mod tests {
1192    use super::*;
1193    use crate::{MultiBuffer, ToPoint};
1194    use rand::prelude::*;
1195    use settings::Settings;
1196    use std::{cmp::Reverse, env, mem, sync::Arc};
1197    use sum_tree::TreeMap;
1198    use text::RandomCharIter;
1199    use util::test::sample_text;
1200    use Bias::{Left, Right};
1201
1202    #[gpui::test]
1203    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1204        cx.set_global(Settings::test(cx));
1205        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1206        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1207        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1208        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1209
1210        let (mut writer, _, _) = map.write(buffer_snapshot, vec![]);
1211        let (snapshot2, edits) = writer.fold(vec![
1212            Point::new(0, 2)..Point::new(2, 2),
1213            Point::new(2, 4)..Point::new(4, 1),
1214        ]);
1215        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1216        assert_eq!(
1217            edits,
1218            &[
1219                FoldEdit {
1220                    old: FoldOffset(2)..FoldOffset(16),
1221                    new: FoldOffset(2)..FoldOffset(5),
1222                },
1223                FoldEdit {
1224                    old: FoldOffset(18)..FoldOffset(29),
1225                    new: FoldOffset(7)..FoldOffset(10)
1226                },
1227            ]
1228        );
1229
1230        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1231            buffer.edit(
1232                vec![
1233                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1234                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1235                ],
1236                None,
1237                cx,
1238            );
1239            buffer.snapshot(cx)
1240        });
1241        let (snapshot3, edits) = map.read(buffer_snapshot, subscription.consume().into_inner());
1242        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1243        assert_eq!(
1244            edits,
1245            &[
1246                FoldEdit {
1247                    old: FoldOffset(0)..FoldOffset(1),
1248                    new: FoldOffset(0)..FoldOffset(3),
1249                },
1250                FoldEdit {
1251                    old: FoldOffset(6)..FoldOffset(6),
1252                    new: FoldOffset(8)..FoldOffset(11),
1253                },
1254            ]
1255        );
1256
1257        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1258            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1259            buffer.snapshot(cx)
1260        });
1261        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1262        assert_eq!(snapshot4.text(), "123a…c123456eee");
1263
1264        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1265        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1266        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1267        assert_eq!(snapshot5.text(), "123a…c123456eee");
1268
1269        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1270        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1271        let (snapshot6, _) = map.read(buffer_snapshot, vec![]);
1272        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1273    }
1274
1275    #[gpui::test]
1276    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1277        cx.set_global(Settings::test(cx));
1278        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1279        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1280        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1281
1282        {
1283            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1284
1285            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1286            writer.fold(vec![5..8]);
1287            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1288            assert_eq!(snapshot.text(), "abcde…ijkl");
1289
1290            // Create an fold adjacent to the start of the first fold.
1291            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1292            writer.fold(vec![0..1, 2..5]);
1293            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1294            assert_eq!(snapshot.text(), "…b…ijkl");
1295
1296            // Create an fold adjacent to the end of the first fold.
1297            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1298            writer.fold(vec![11..11, 8..10]);
1299            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1300            assert_eq!(snapshot.text(), "…b…kl");
1301        }
1302
1303        {
1304            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1305
1306            // Create two adjacent folds.
1307            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1308            writer.fold(vec![0..2, 2..5]);
1309            let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1310            assert_eq!(snapshot.text(), "…fghijkl");
1311
1312            // Edit within one of the folds.
1313            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1314                buffer.edit([(0..1, "12345")], None, cx);
1315                buffer.snapshot(cx)
1316            });
1317            let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1318            assert_eq!(snapshot.text(), "12345…fghijkl");
1319        }
1320    }
1321
1322    #[gpui::test]
1323    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1324        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1325        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1326        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1327        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1328        writer.fold(vec![
1329            Point::new(0, 2)..Point::new(2, 2),
1330            Point::new(0, 4)..Point::new(1, 0),
1331            Point::new(1, 2)..Point::new(3, 2),
1332            Point::new(3, 1)..Point::new(4, 1),
1333        ]);
1334        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1335        assert_eq!(snapshot.text(), "aa…eeeee");
1336    }
1337
1338    #[gpui::test]
1339    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1340        cx.set_global(Settings::test(cx));
1341        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1342        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1343        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1344        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1345
1346        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1347        writer.fold(vec![
1348            Point::new(0, 2)..Point::new(2, 2),
1349            Point::new(3, 1)..Point::new(4, 1),
1350        ]);
1351        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1352        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1353
1354        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1355            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1356            buffer.snapshot(cx)
1357        });
1358        let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1359        assert_eq!(snapshot.text(), "aa…eeeee");
1360    }
1361
1362    #[gpui::test]
1363    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1364        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1365        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1366        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1367
1368        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1369        writer.fold(vec![
1370            Point::new(0, 2)..Point::new(2, 2),
1371            Point::new(0, 4)..Point::new(1, 0),
1372            Point::new(1, 2)..Point::new(3, 2),
1373            Point::new(3, 1)..Point::new(4, 1),
1374        ]);
1375        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1376        let fold_ranges = snapshot
1377            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1378            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1379            .collect::<Vec<_>>();
1380        assert_eq!(
1381            fold_ranges,
1382            vec![
1383                Point::new(0, 2)..Point::new(2, 2),
1384                Point::new(1, 2)..Point::new(3, 2)
1385            ]
1386        );
1387    }
1388
1389    #[gpui::test(iterations = 100)]
1390    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1391        cx.set_global(Settings::test(cx));
1392        let operations = env::var("OPERATIONS")
1393            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1394            .unwrap_or(10);
1395
1396        let len = rng.gen_range(0..10);
1397        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1398        let buffer = if rng.gen() {
1399            MultiBuffer::build_simple(&text, cx)
1400        } else {
1401            MultiBuffer::build_random(&mut rng, cx)
1402        };
1403        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1404        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1405
1406        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1407        let mut snapshot_edits = Vec::new();
1408
1409        let mut highlights = TreeMap::default();
1410        let highlight_count = rng.gen_range(0_usize..10);
1411        let mut highlight_ranges = (0..highlight_count)
1412            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1413            .collect::<Vec<_>>();
1414        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1415        log::info!("highlighting ranges {:?}", highlight_ranges);
1416        let highlight_ranges = highlight_ranges
1417            .into_iter()
1418            .map(|range| {
1419                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1420            })
1421            .collect::<Vec<_>>();
1422
1423        highlights.insert(
1424            Some(TypeId::of::<()>()),
1425            Arc::new((HighlightStyle::default(), highlight_ranges)),
1426        );
1427
1428        for _ in 0..operations {
1429            log::info!("text: {:?}", buffer_snapshot.text());
1430            let mut buffer_edits = Vec::new();
1431            match rng.gen_range(0..=100) {
1432                0..=59 => {
1433                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1434                }
1435                _ => buffer.update(cx, |buffer, cx| {
1436                    let subscription = buffer.subscribe();
1437                    let edit_count = rng.gen_range(1..=5);
1438                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1439                    buffer_snapshot = buffer.snapshot(cx);
1440                    let edits = subscription.consume().into_inner();
1441                    log::info!("editing {:?}", edits);
1442                    buffer_edits.extend(edits);
1443                }),
1444            };
1445
1446            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1447            snapshot_edits.push((snapshot.clone(), edits));
1448
1449            let mut expected_text: String = buffer_snapshot.text().to_string();
1450            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1451                expected_text.replace_range(fold_range.start..fold_range.end, "…");
1452            }
1453
1454            assert_eq!(snapshot.text(), expected_text);
1455            log::info!(
1456                "fold text {:?} ({} lines)",
1457                expected_text,
1458                expected_text.matches('\n').count() + 1
1459            );
1460
1461            let mut prev_row = 0;
1462            let mut expected_buffer_rows = Vec::new();
1463            for fold_range in map.merged_fold_ranges().into_iter() {
1464                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1465                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1466                expected_buffer_rows.extend(
1467                    buffer_snapshot
1468                        .buffer_rows(prev_row)
1469                        .take((1 + fold_start - prev_row) as usize),
1470                );
1471                prev_row = 1 + fold_end;
1472            }
1473            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1474
1475            assert_eq!(
1476                expected_buffer_rows.len(),
1477                expected_text.matches('\n').count() + 1,
1478                "wrong expected buffer rows {:?}. text: {:?}",
1479                expected_buffer_rows,
1480                expected_text
1481            );
1482
1483            for (output_row, line) in expected_text.lines().enumerate() {
1484                let line_len = snapshot.line_len(output_row as u32);
1485                assert_eq!(line_len, line.len() as u32);
1486            }
1487
1488            let longest_row = snapshot.longest_row();
1489            let longest_char_column = expected_text
1490                .split('\n')
1491                .nth(longest_row as usize)
1492                .unwrap()
1493                .chars()
1494                .count();
1495            let mut fold_point = FoldPoint::new(0, 0);
1496            let mut fold_offset = FoldOffset(0);
1497            let mut char_column = 0;
1498            for c in expected_text.chars() {
1499                let buffer_point = fold_point.to_buffer_point(&snapshot);
1500                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1501                assert_eq!(
1502                    snapshot.to_fold_point(buffer_point, Right),
1503                    fold_point,
1504                    "{:?} -> fold point",
1505                    buffer_point,
1506                );
1507                assert_eq!(
1508                    fold_point.to_buffer_offset(&snapshot),
1509                    buffer_offset,
1510                    "fold_point.to_buffer_offset({:?})",
1511                    fold_point,
1512                );
1513                assert_eq!(
1514                    fold_point.to_offset(&snapshot),
1515                    fold_offset,
1516                    "fold_point.to_offset({:?})",
1517                    fold_point,
1518                );
1519
1520                if c == '\n' {
1521                    *fold_point.row_mut() += 1;
1522                    *fold_point.column_mut() = 0;
1523                    char_column = 0;
1524                } else {
1525                    *fold_point.column_mut() += c.len_utf8() as u32;
1526                    char_column += 1;
1527                }
1528                fold_offset.0 += c.len_utf8();
1529                if char_column > longest_char_column {
1530                    panic!(
1531                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1532                        longest_row,
1533                        longest_char_column,
1534                        fold_point.row(),
1535                        char_column
1536                    );
1537                }
1538            }
1539
1540            for _ in 0..5 {
1541                let mut start = snapshot
1542                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1543                let mut end = snapshot
1544                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1545                if start > end {
1546                    mem::swap(&mut start, &mut end);
1547                }
1548
1549                let text = &expected_text[start.0..end.0];
1550                assert_eq!(
1551                    snapshot
1552                        .chunks(start..end, false, Some(&highlights))
1553                        .map(|c| c.text)
1554                        .collect::<String>(),
1555                    text,
1556                );
1557            }
1558
1559            let mut fold_row = 0;
1560            while fold_row < expected_buffer_rows.len() as u32 {
1561                fold_row = snapshot
1562                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1563                    .row();
1564                assert_eq!(
1565                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1566                    expected_buffer_rows[(fold_row as usize)..],
1567                    "wrong buffer rows starting at fold row {}",
1568                    fold_row,
1569                );
1570                fold_row += 1;
1571            }
1572
1573            for fold_range in map.merged_fold_ranges() {
1574                let fold_point =
1575                    snapshot.to_fold_point(fold_range.start.to_point(&buffer_snapshot), Right);
1576                assert!(snapshot.is_line_folded(fold_point.row()));
1577            }
1578
1579            for _ in 0..5 {
1580                let end =
1581                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1582                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1583                let expected_folds = map
1584                    .folds
1585                    .items(&buffer_snapshot)
1586                    .into_iter()
1587                    .filter(|fold| {
1588                        let start = buffer_snapshot.anchor_before(start);
1589                        let end = buffer_snapshot.anchor_after(end);
1590                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1591                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1592                    })
1593                    .map(|fold| fold.0)
1594                    .collect::<Vec<_>>();
1595
1596                assert_eq!(
1597                    snapshot
1598                        .folds_in_range(start..end)
1599                        .cloned()
1600                        .collect::<Vec<_>>(),
1601                    expected_folds
1602                );
1603            }
1604
1605            let text = snapshot.text();
1606            for _ in 0..5 {
1607                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1608                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1609                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1610                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1611                let mut start =
1612                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1613                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1614                if start > end {
1615                    mem::swap(&mut start, &mut end);
1616                }
1617
1618                let lines = start..end;
1619                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1620                assert_eq!(
1621                    snapshot.text_summary_for_range(lines),
1622                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1623                )
1624            }
1625
1626            let mut text = initial_snapshot.text();
1627            for (snapshot, edits) in snapshot_edits.drain(..) {
1628                let new_text = snapshot.text();
1629                for edit in edits {
1630                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1631                    let new_bytes = edit.new.start.0..edit.new.end.0;
1632                    text.replace_range(old_bytes, &new_text[new_bytes]);
1633                }
1634
1635                assert_eq!(text, new_text);
1636                initial_snapshot = snapshot;
1637            }
1638        }
1639    }
1640
1641    #[gpui::test]
1642    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1643        let text = sample_text(6, 6, 'a') + "\n";
1644        let buffer = MultiBuffer::build_simple(&text, cx);
1645
1646        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1647        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1648
1649        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1650        writer.fold(vec![
1651            Point::new(0, 2)..Point::new(2, 2),
1652            Point::new(3, 1)..Point::new(4, 1),
1653        ]);
1654
1655        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1656        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1657        assert_eq!(
1658            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1659            [Some(0), Some(3), Some(5), Some(6)]
1660        );
1661        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1662    }
1663
1664    impl FoldMap {
1665        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1666            let buffer = self.buffer.lock().clone();
1667            let mut folds = self.folds.items(&buffer);
1668            // Ensure sorting doesn't change how folds get merged and displayed.
1669            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer));
1670            let mut fold_ranges = folds
1671                .iter()
1672                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1673                .peekable();
1674
1675            let mut merged_ranges = Vec::new();
1676            while let Some(mut fold_range) = fold_ranges.next() {
1677                while let Some(next_range) = fold_ranges.peek() {
1678                    if fold_range.end >= next_range.start {
1679                        if next_range.end > fold_range.end {
1680                            fold_range.end = next_range.end;
1681                        }
1682                        fold_ranges.next();
1683                    } else {
1684                        break;
1685                    }
1686                }
1687                if fold_range.end > fold_range.start {
1688                    merged_ranges.push(fold_range);
1689                }
1690            }
1691            merged_ranges
1692        }
1693
1694        pub fn randomly_mutate(
1695            &mut self,
1696            rng: &mut impl Rng,
1697        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1698            let mut snapshot_edits = Vec::new();
1699            match rng.gen_range(0..=100) {
1700                0..=39 if !self.folds.is_empty() => {
1701                    let buffer = self.buffer.lock().clone();
1702                    let mut to_unfold = Vec::new();
1703                    for _ in 0..rng.gen_range(1..=3) {
1704                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1705                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1706                        to_unfold.push(start..end);
1707                    }
1708                    log::info!("unfolding {:?}", to_unfold);
1709                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1710                    snapshot_edits.push((snapshot, edits));
1711                    let (snapshot, edits) = writer.fold(to_unfold);
1712                    snapshot_edits.push((snapshot, edits));
1713                }
1714                _ => {
1715                    let buffer = self.buffer.lock().clone();
1716                    let mut to_fold = Vec::new();
1717                    for _ in 0..rng.gen_range(1..=2) {
1718                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1719                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1720                        to_fold.push(start..end);
1721                    }
1722                    log::info!("folding {:?}", to_fold);
1723                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1724                    snapshot_edits.push((snapshot, edits));
1725                    let (snapshot, edits) = writer.fold(to_fold);
1726                    snapshot_edits.push((snapshot, edits));
1727                }
1728            }
1729            snapshot_edits
1730        }
1731    }
1732}