1use super::TextHighlights;
   2use crate::{
   3    multi_buffer::MultiBufferRows, Anchor, AnchorRangeExt, MultiBufferChunks, MultiBufferSnapshot,
   4    ToOffset,
   5};
   6use collections::BTreeMap;
   7use gpui::{color::Color, 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 Point);
  22
  23impl FoldPoint {
  24    pub fn new(row: u32, column: u32) -> Self {
  25        Self(Point::new(row, column))
  26    }
  27
  28    pub fn row(self) -> u32 {
  29        self.0.row
  30    }
  31
  32    pub fn row_mut(&mut self) -> &mut u32 {
  33        &mut self.0.row
  34    }
  35
  36    pub fn column_mut(&mut self) -> &mut u32 {
  37        &mut self.0.column
  38    }
  39
  40    pub fn to_buffer_point(self, snapshot: &FoldSnapshot) -> Point {
  41        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  42        cursor.seek(&self, Bias::Right, &());
  43        let overshoot = self.0 - cursor.start().0 .0;
  44        cursor.start().1 + overshoot
  45    }
  46
  47    pub fn to_buffer_offset(self, snapshot: &FoldSnapshot) -> usize {
  48        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  49        cursor.seek(&self, Bias::Right, &());
  50        let overshoot = self.0 - cursor.start().0 .0;
  51        snapshot
  52            .buffer_snapshot
  53            .point_to_offset(cursor.start().1 + overshoot)
  54    }
  55
  56    pub fn to_offset(self, snapshot: &FoldSnapshot) -> FoldOffset {
  57        let mut cursor = snapshot
  58            .transforms
  59            .cursor::<(FoldPoint, TransformSummary)>();
  60        cursor.seek(&self, Bias::Right, &());
  61        let overshoot = self.0 - cursor.start().1.output.lines;
  62        let mut offset = cursor.start().1.output.len;
  63        if !overshoot.is_zero() {
  64            let transform = cursor.item().expect("display point out of range");
  65            assert!(transform.output_text.is_none());
  66            let end_buffer_offset = snapshot
  67                .buffer_snapshot
  68                .point_to_offset(cursor.start().1.input.lines + overshoot);
  69            offset += end_buffer_offset - cursor.start().1.input.len;
  70        }
  71        FoldOffset(offset)
  72    }
  73}
  74
  75impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
  76    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
  77        self.0 += &summary.output.lines;
  78    }
  79}
  80
  81pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  82
  83impl<'a> FoldMapWriter<'a> {
  84    pub fn fold<T: ToOffset>(
  85        &mut self,
  86        ranges: impl IntoIterator<Item = Range<T>>,
  87    ) -> (FoldSnapshot, Vec<FoldEdit>) {
  88        let mut edits = Vec::new();
  89        let mut folds = Vec::new();
  90        let buffer = self.0.buffer.lock().clone();
  91        for range in ranges.into_iter() {
  92            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
  93
  94            // Ignore any empty ranges.
  95            if range.start == range.end {
  96                continue;
  97            }
  98
  99            // For now, ignore any ranges that span an excerpt boundary.
 100            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 101            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 102                continue;
 103            }
 104
 105            folds.push(fold);
 106            edits.push(text::Edit {
 107                old: range.clone(),
 108                new: range,
 109            });
 110        }
 111
 112        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 113
 114        self.0.folds = {
 115            let mut new_tree = SumTree::new();
 116            let mut cursor = self.0.folds.cursor::<Fold>();
 117            for fold in folds {
 118                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 119                new_tree.push(fold, &buffer);
 120            }
 121            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 122            new_tree
 123        };
 124
 125        consolidate_buffer_edits(&mut edits);
 126        let edits = self.0.sync(buffer.clone(), edits);
 127        let snapshot = FoldSnapshot {
 128            transforms: self.0.transforms.lock().clone(),
 129            folds: self.0.folds.clone(),
 130            buffer_snapshot: buffer,
 131            version: self.0.version.load(SeqCst),
 132            ellipses_color: self.0.ellipses_color,
 133        };
 134        (snapshot, edits)
 135    }
 136
 137    pub fn unfold<T: ToOffset>(
 138        &mut self,
 139        ranges: impl IntoIterator<Item = Range<T>>,
 140        inclusive: bool,
 141    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 142        let mut edits = Vec::new();
 143        let mut fold_ixs_to_delete = Vec::new();
 144        let buffer = self.0.buffer.lock().clone();
 145        for range in ranges.into_iter() {
 146            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 147            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, inclusive);
 148            while let Some(fold) = folds_cursor.item() {
 149                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 150                if offset_range.end > offset_range.start {
 151                    edits.push(text::Edit {
 152                        old: offset_range.clone(),
 153                        new: offset_range,
 154                    });
 155                }
 156                fold_ixs_to_delete.push(*folds_cursor.start());
 157                folds_cursor.next(&buffer);
 158            }
 159        }
 160
 161        fold_ixs_to_delete.sort_unstable();
 162        fold_ixs_to_delete.dedup();
 163
 164        self.0.folds = {
 165            let mut cursor = self.0.folds.cursor::<usize>();
 166            let mut folds = SumTree::new();
 167            for fold_ix in fold_ixs_to_delete {
 168                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 169                cursor.next(&buffer);
 170            }
 171            folds.push_tree(cursor.suffix(&buffer), &buffer);
 172            folds
 173        };
 174
 175        consolidate_buffer_edits(&mut edits);
 176        let edits = self.0.sync(buffer.clone(), edits);
 177        let snapshot = FoldSnapshot {
 178            transforms: self.0.transforms.lock().clone(),
 179            folds: self.0.folds.clone(),
 180            buffer_snapshot: buffer,
 181            version: self.0.version.load(SeqCst),
 182            ellipses_color: self.0.ellipses_color,
 183        };
 184        (snapshot, edits)
 185    }
 186}
 187
 188pub struct FoldMap {
 189    buffer: Mutex<MultiBufferSnapshot>,
 190    transforms: Mutex<SumTree<Transform>>,
 191    folds: SumTree<Fold>,
 192    version: AtomicUsize,
 193    ellipses_color: Option<Color>,
 194}
 195
 196impl FoldMap {
 197    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 198        let this = Self {
 199            buffer: Mutex::new(buffer.clone()),
 200            folds: Default::default(),
 201            transforms: Mutex::new(SumTree::from_item(
 202                Transform {
 203                    summary: TransformSummary {
 204                        input: buffer.text_summary(),
 205                        output: buffer.text_summary(),
 206                    },
 207                    output_text: None,
 208                },
 209                &(),
 210            )),
 211            ellipses_color: None,
 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            ellipses_color: None,
 221        };
 222        (this, snapshot)
 223    }
 224
 225    pub fn read(
 226        &self,
 227        buffer: MultiBufferSnapshot,
 228        edits: Vec<Edit<usize>>,
 229    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 230        let edits = self.sync(buffer, edits);
 231        self.check_invariants();
 232        let snapshot = FoldSnapshot {
 233            transforms: self.transforms.lock().clone(),
 234            folds: self.folds.clone(),
 235            buffer_snapshot: self.buffer.lock().clone(),
 236            version: self.version.load(SeqCst),
 237            ellipses_color: self.ellipses_color,
 238        };
 239        (snapshot, edits)
 240    }
 241
 242    pub fn write(
 243        &mut self,
 244        buffer: MultiBufferSnapshot,
 245        edits: Vec<Edit<usize>>,
 246    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 247        let (snapshot, edits) = self.read(buffer, edits);
 248        (FoldMapWriter(self), snapshot, edits)
 249    }
 250
 251    pub fn set_ellipses_color(&mut self, color: Color) -> bool {
 252        if self.ellipses_color != Some(color) {
 253            self.ellipses_color = Some(color);
 254            true
 255        } else {
 256            false
 257        }
 258    }
 259
 260    fn check_invariants(&self) {
 261        if cfg!(test) {
 262            assert_eq!(
 263                self.transforms.lock().summary().input.len,
 264                self.buffer.lock().len(),
 265                "transform tree does not match buffer's length"
 266            );
 267
 268            let mut folds = self.folds.iter().peekable();
 269            while let Some(fold) = folds.next() {
 270                if let Some(next_fold) = folds.peek() {
 271                    let comparison = fold.0.cmp(&next_fold.0, &self.buffer.lock());
 272                    assert!(comparison.is_le());
 273                }
 274            }
 275        }
 276    }
 277
 278    fn sync(
 279        &self,
 280        new_buffer: MultiBufferSnapshot,
 281        buffer_edits: Vec<text::Edit<usize>>,
 282    ) -> Vec<FoldEdit> {
 283        if buffer_edits.is_empty() {
 284            let mut buffer = self.buffer.lock();
 285            if buffer.edit_count() != new_buffer.edit_count()
 286                || buffer.parse_count() != new_buffer.parse_count()
 287                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 288                || buffer.git_diff_update_count() != new_buffer.git_diff_update_count()
 289                || buffer.trailing_excerpt_update_count()
 290                    != new_buffer.trailing_excerpt_update_count()
 291            {
 292                self.version.fetch_add(1, SeqCst);
 293            }
 294            *buffer = new_buffer;
 295            Vec::new()
 296        } else {
 297            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 298
 299            let mut new_transforms = SumTree::new();
 300            let mut transforms = self.transforms.lock();
 301            let mut cursor = transforms.cursor::<usize>();
 302            cursor.seek(&0, Bias::Right, &());
 303
 304            while let Some(mut edit) = buffer_edits_iter.next() {
 305                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 306                edit.new.start -= edit.old.start - cursor.start();
 307                edit.old.start = *cursor.start();
 308
 309                cursor.seek(&edit.old.end, Bias::Right, &());
 310                cursor.next(&());
 311
 312                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 313                loop {
 314                    edit.old.end = *cursor.start();
 315
 316                    if let Some(next_edit) = buffer_edits_iter.peek() {
 317                        if next_edit.old.start > edit.old.end {
 318                            break;
 319                        }
 320
 321                        let next_edit = buffer_edits_iter.next().unwrap();
 322                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 323
 324                        if next_edit.old.end >= edit.old.end {
 325                            edit.old.end = next_edit.old.end;
 326                            cursor.seek(&edit.old.end, Bias::Right, &());
 327                            cursor.next(&());
 328                        }
 329                    } else {
 330                        break;
 331                    }
 332                }
 333
 334                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 335
 336                let anchor = new_buffer.anchor_before(edit.new.start);
 337                let mut folds_cursor = self.folds.cursor::<Fold>();
 338                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 339
 340                let mut folds = iter::from_fn({
 341                    let buffer = &new_buffer;
 342                    move || {
 343                        let item = folds_cursor
 344                            .item()
 345                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 346                        folds_cursor.next(buffer);
 347                        item
 348                    }
 349                })
 350                .peekable();
 351
 352                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 353                    let mut fold = folds.next().unwrap();
 354                    let sum = new_transforms.summary();
 355
 356                    assert!(fold.start >= sum.input.len);
 357
 358                    while folds
 359                        .peek()
 360                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 361                    {
 362                        let next_fold = folds.next().unwrap();
 363                        if next_fold.end > fold.end {
 364                            fold.end = next_fold.end;
 365                        }
 366                    }
 367
 368                    if fold.start > sum.input.len {
 369                        let text_summary = new_buffer
 370                            .text_summary_for_range::<TextSummary, _>(sum.input.len..fold.start);
 371                        new_transforms.push(
 372                            Transform {
 373                                summary: TransformSummary {
 374                                    output: text_summary.clone(),
 375                                    input: text_summary,
 376                                },
 377                                output_text: None,
 378                            },
 379                            &(),
 380                        );
 381                    }
 382
 383                    if fold.end > fold.start {
 384                        let output_text = "⋯";
 385                        new_transforms.push(
 386                            Transform {
 387                                summary: TransformSummary {
 388                                    output: TextSummary::from(output_text),
 389                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 390                                },
 391                                output_text: Some(output_text),
 392                            },
 393                            &(),
 394                        );
 395                    }
 396                }
 397
 398                let sum = new_transforms.summary();
 399                if sum.input.len < edit.new.end {
 400                    let text_summary = new_buffer
 401                        .text_summary_for_range::<TextSummary, _>(sum.input.len..edit.new.end);
 402                    new_transforms.push(
 403                        Transform {
 404                            summary: TransformSummary {
 405                                output: text_summary.clone(),
 406                                input: text_summary,
 407                            },
 408                            output_text: None,
 409                        },
 410                        &(),
 411                    );
 412                }
 413            }
 414
 415            new_transforms.push_tree(cursor.suffix(&()), &());
 416            if new_transforms.is_empty() {
 417                let text_summary = new_buffer.text_summary();
 418                new_transforms.push(
 419                    Transform {
 420                        summary: TransformSummary {
 421                            output: text_summary.clone(),
 422                            input: text_summary,
 423                        },
 424                        output_text: None,
 425                    },
 426                    &(),
 427                );
 428            }
 429
 430            drop(cursor);
 431
 432            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 433            {
 434                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 435                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 436
 437                for mut edit in buffer_edits {
 438                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 439                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 440                        edit.old.start = old_transforms.start().0;
 441                    }
 442                    let old_start =
 443                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 444
 445                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 446                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 447                        old_transforms.next(&());
 448                        edit.old.end = old_transforms.start().0;
 449                    }
 450                    let old_end =
 451                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 452
 453                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 454                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 455                        edit.new.start = new_transforms.start().0;
 456                    }
 457                    let new_start =
 458                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 459
 460                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 461                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 462                        new_transforms.next(&());
 463                        edit.new.end = new_transforms.start().0;
 464                    }
 465                    let new_end =
 466                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 467
 468                    fold_edits.push(FoldEdit {
 469                        old: FoldOffset(old_start)..FoldOffset(old_end),
 470                        new: FoldOffset(new_start)..FoldOffset(new_end),
 471                    });
 472                }
 473
 474                consolidate_fold_edits(&mut fold_edits);
 475            }
 476
 477            *transforms = new_transforms;
 478            *self.buffer.lock() = new_buffer;
 479            self.version.fetch_add(1, SeqCst);
 480            fold_edits
 481        }
 482    }
 483}
 484
 485#[derive(Clone)]
 486pub struct FoldSnapshot {
 487    transforms: SumTree<Transform>,
 488    folds: SumTree<Fold>,
 489    buffer_snapshot: MultiBufferSnapshot,
 490    pub version: usize,
 491    pub ellipses_color: Option<Color>,
 492}
 493
 494impl FoldSnapshot {
 495    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 496        &self.buffer_snapshot
 497    }
 498
 499    #[cfg(test)]
 500    pub fn text(&self) -> String {
 501        self.chunks(FoldOffset(0)..self.len(), false, None)
 502            .map(|c| c.text)
 503            .collect()
 504    }
 505
 506    #[cfg(test)]
 507    pub fn fold_count(&self) -> usize {
 508        self.folds.items(&self.buffer_snapshot).len()
 509    }
 510
 511    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 512        let mut summary = TextSummary::default();
 513
 514        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 515        cursor.seek(&range.start, Bias::Right, &());
 516        if let Some(transform) = cursor.item() {
 517            let start_in_transform = range.start.0 - cursor.start().0 .0;
 518            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 519            if let Some(output_text) = transform.output_text {
 520                summary = TextSummary::from(
 521                    &output_text
 522                        [start_in_transform.column as usize..end_in_transform.column as usize],
 523                );
 524            } else {
 525                let buffer_start = cursor.start().1 + start_in_transform;
 526                let buffer_end = cursor.start().1 + end_in_transform;
 527                summary = self
 528                    .buffer_snapshot
 529                    .text_summary_for_range(buffer_start..buffer_end);
 530            }
 531        }
 532
 533        if range.end > cursor.end(&()).0 {
 534            cursor.next(&());
 535            summary += &cursor
 536                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 537                .output;
 538            if let Some(transform) = cursor.item() {
 539                let end_in_transform = range.end.0 - cursor.start().0 .0;
 540                if let Some(output_text) = transform.output_text {
 541                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 542                } else {
 543                    let buffer_start = cursor.start().1;
 544                    let buffer_end = cursor.start().1 + end_in_transform;
 545                    summary += self
 546                        .buffer_snapshot
 547                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 548                }
 549            }
 550        }
 551
 552        summary
 553    }
 554
 555    pub fn to_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
 556        let mut cursor = self.transforms.cursor::<(Point, FoldPoint)>();
 557        cursor.seek(&point, Bias::Right, &());
 558        if cursor.item().map_or(false, |t| t.is_fold()) {
 559            if bias == Bias::Left || point == cursor.start().0 {
 560                cursor.start().1
 561            } else {
 562                cursor.end(&()).1
 563            }
 564        } else {
 565            let overshoot = point - cursor.start().0;
 566            FoldPoint(cmp::min(
 567                cursor.start().1 .0 + overshoot,
 568                cursor.end(&()).1 .0,
 569            ))
 570        }
 571    }
 572
 573    pub fn len(&self) -> FoldOffset {
 574        FoldOffset(self.transforms.summary().output.len)
 575    }
 576
 577    pub fn line_len(&self, row: u32) -> u32 {
 578        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 579        let line_end = if row >= self.max_point().row() {
 580            self.len().0
 581        } else {
 582            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 583        };
 584        (line_end - line_start) as u32
 585    }
 586
 587    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 588        if start_row > self.transforms.summary().output.lines.row {
 589            panic!("invalid display row {}", start_row);
 590        }
 591
 592        let fold_point = FoldPoint::new(start_row, 0);
 593        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 594        cursor.seek(&fold_point, Bias::Left, &());
 595
 596        let overshoot = fold_point.0 - cursor.start().0 .0;
 597        let buffer_point = cursor.start().1 + overshoot;
 598        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 599
 600        FoldBufferRows {
 601            fold_point,
 602            input_buffer_rows,
 603            cursor,
 604        }
 605    }
 606
 607    pub fn max_point(&self) -> FoldPoint {
 608        FoldPoint(self.transforms.summary().output.lines)
 609    }
 610
 611    #[cfg(test)]
 612    pub fn longest_row(&self) -> u32 {
 613        self.transforms.summary().output.longest_row
 614    }
 615
 616    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Range<Anchor>>
 617    where
 618        T: ToOffset,
 619    {
 620        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 621        iter::from_fn(move || {
 622            let item = folds.item().map(|f| &f.0);
 623            folds.next(&self.buffer_snapshot);
 624            item
 625        })
 626    }
 627
 628    pub fn intersects_fold<T>(&self, offset: T) -> bool
 629    where
 630        T: ToOffset,
 631    {
 632        let offset = offset.to_offset(&self.buffer_snapshot);
 633        let mut cursor = self.transforms.cursor::<usize>();
 634        cursor.seek(&offset, Bias::Right, &());
 635        cursor.item().map_or(false, |t| t.output_text.is_some())
 636    }
 637
 638    pub fn is_line_folded(&self, buffer_row: u32) -> bool {
 639        let mut cursor = self.transforms.cursor::<Point>();
 640        cursor.seek(&Point::new(buffer_row, 0), Bias::Right, &());
 641        while let Some(transform) = cursor.item() {
 642            if transform.output_text.is_some() {
 643                return true;
 644            }
 645            if cursor.end(&()).row == buffer_row {
 646                cursor.next(&())
 647            } else {
 648                break;
 649            }
 650        }
 651        false
 652    }
 653
 654    pub fn chunks<'a>(
 655        &'a self,
 656        range: Range<FoldOffset>,
 657        language_aware: bool,
 658        text_highlights: Option<&'a TextHighlights>,
 659    ) -> FoldChunks<'a> {
 660        let mut highlight_endpoints = Vec::new();
 661        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 662
 663        let buffer_end = {
 664            transform_cursor.seek(&range.end, Bias::Right, &());
 665            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 666            transform_cursor.start().1 + overshoot
 667        };
 668
 669        let buffer_start = {
 670            transform_cursor.seek(&range.start, Bias::Right, &());
 671            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 672            transform_cursor.start().1 + overshoot
 673        };
 674
 675        if let Some(text_highlights) = text_highlights {
 676            if !text_highlights.is_empty() {
 677                while transform_cursor.start().0 < range.end {
 678                    if !transform_cursor.item().unwrap().is_fold() {
 679                        let transform_start = self
 680                            .buffer_snapshot
 681                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 682
 683                        let transform_end = {
 684                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 685                            self.buffer_snapshot.anchor_before(cmp::min(
 686                                transform_cursor.end(&()).1,
 687                                transform_cursor.start().1 + overshoot,
 688                            ))
 689                        };
 690
 691                        for (tag, highlights) in text_highlights.iter() {
 692                            let style = highlights.0;
 693                            let ranges = &highlights.1;
 694
 695                            let start_ix = match ranges.binary_search_by(|probe| {
 696                                let cmp = probe.end.cmp(&transform_start, self.buffer_snapshot());
 697                                if cmp.is_gt() {
 698                                    Ordering::Greater
 699                                } else {
 700                                    Ordering::Less
 701                                }
 702                            }) {
 703                                Ok(i) | Err(i) => i,
 704                            };
 705                            for range in &ranges[start_ix..] {
 706                                if range
 707                                    .start
 708                                    .cmp(&transform_end, &self.buffer_snapshot)
 709                                    .is_ge()
 710                                {
 711                                    break;
 712                                }
 713
 714                                highlight_endpoints.push(HighlightEndpoint {
 715                                    offset: range.start.to_offset(&self.buffer_snapshot),
 716                                    is_start: true,
 717                                    tag: *tag,
 718                                    style,
 719                                });
 720                                highlight_endpoints.push(HighlightEndpoint {
 721                                    offset: range.end.to_offset(&self.buffer_snapshot),
 722                                    is_start: false,
 723                                    tag: *tag,
 724                                    style,
 725                                });
 726                            }
 727                        }
 728                    }
 729
 730                    transform_cursor.next(&());
 731                }
 732                highlight_endpoints.sort();
 733                transform_cursor.seek(&range.start, Bias::Right, &());
 734            }
 735        }
 736
 737        FoldChunks {
 738            transform_cursor,
 739            buffer_chunks: self
 740                .buffer_snapshot
 741                .chunks(buffer_start..buffer_end, language_aware),
 742            buffer_chunk: None,
 743            buffer_offset: buffer_start,
 744            output_offset: range.start.0,
 745            max_output_offset: range.end.0,
 746            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 747            active_highlights: Default::default(),
 748            ellipses_color: self.ellipses_color,
 749        }
 750    }
 751
 752    #[cfg(test)]
 753    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 754        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 755        cursor.seek(&offset, Bias::Right, &());
 756        if let Some(transform) = cursor.item() {
 757            let transform_start = cursor.start().0 .0;
 758            if transform.output_text.is_some() {
 759                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 760                    FoldOffset(transform_start)
 761                } else {
 762                    FoldOffset(cursor.end(&()).0 .0)
 763                }
 764            } else {
 765                let overshoot = offset.0 - transform_start;
 766                let buffer_offset = cursor.start().1 + overshoot;
 767                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 768                FoldOffset(
 769                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 770                        as usize,
 771                )
 772            }
 773        } else {
 774            FoldOffset(self.transforms.summary().output.len)
 775        }
 776    }
 777
 778    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 779        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 780        cursor.seek(&point, Bias::Right, &());
 781        if let Some(transform) = cursor.item() {
 782            let transform_start = cursor.start().0 .0;
 783            if transform.output_text.is_some() {
 784                if point.0 == transform_start || matches!(bias, Bias::Left) {
 785                    FoldPoint(transform_start)
 786                } else {
 787                    FoldPoint(cursor.end(&()).0 .0)
 788                }
 789            } else {
 790                let overshoot = point.0 - transform_start;
 791                let buffer_position = cursor.start().1 + overshoot;
 792                let clipped_buffer_position =
 793                    self.buffer_snapshot.clip_point(buffer_position, bias);
 794                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 795            }
 796        } else {
 797            FoldPoint(self.transforms.summary().output.lines)
 798        }
 799    }
 800}
 801
 802fn intersecting_folds<'a, T>(
 803    buffer: &'a MultiBufferSnapshot,
 804    folds: &'a SumTree<Fold>,
 805    range: Range<T>,
 806    inclusive: bool,
 807) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 808where
 809    T: ToOffset,
 810{
 811    let start = buffer.anchor_before(range.start.to_offset(buffer));
 812    let end = buffer.anchor_after(range.end.to_offset(buffer));
 813    let mut cursor = folds.filter::<_, usize>(move |summary| {
 814        let start_cmp = start.cmp(&summary.max_end, buffer);
 815        let end_cmp = end.cmp(&summary.min_start, buffer);
 816
 817        if inclusive {
 818            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 819        } else {
 820            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 821        }
 822    });
 823    cursor.next(buffer);
 824    cursor
 825}
 826
 827fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 828    edits.sort_unstable_by(|a, b| {
 829        a.old
 830            .start
 831            .cmp(&b.old.start)
 832            .then_with(|| b.old.end.cmp(&a.old.end))
 833    });
 834
 835    let mut i = 1;
 836    while i < edits.len() {
 837        let edit = edits[i].clone();
 838        let prev_edit = &mut edits[i - 1];
 839        if prev_edit.old.end >= edit.old.start {
 840            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 841            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 842            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 843            edits.remove(i);
 844            continue;
 845        }
 846        i += 1;
 847    }
 848}
 849
 850fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 851    edits.sort_unstable_by(|a, b| {
 852        a.old
 853            .start
 854            .cmp(&b.old.start)
 855            .then_with(|| b.old.end.cmp(&a.old.end))
 856    });
 857
 858    let mut i = 1;
 859    while i < edits.len() {
 860        let edit = edits[i].clone();
 861        let prev_edit = &mut edits[i - 1];
 862        if prev_edit.old.end >= edit.old.start {
 863            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 864            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 865            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 866            edits.remove(i);
 867            continue;
 868        }
 869        i += 1;
 870    }
 871}
 872
 873#[derive(Clone, Debug, Default, Eq, PartialEq)]
 874struct Transform {
 875    summary: TransformSummary,
 876    output_text: Option<&'static str>,
 877}
 878
 879impl Transform {
 880    fn is_fold(&self) -> bool {
 881        self.output_text.is_some()
 882    }
 883}
 884
 885#[derive(Clone, Debug, Default, Eq, PartialEq)]
 886struct TransformSummary {
 887    output: TextSummary,
 888    input: TextSummary,
 889}
 890
 891impl sum_tree::Item for Transform {
 892    type Summary = TransformSummary;
 893
 894    fn summary(&self) -> Self::Summary {
 895        self.summary.clone()
 896    }
 897}
 898
 899impl sum_tree::Summary for TransformSummary {
 900    type Context = ();
 901
 902    fn add_summary(&mut self, other: &Self, _: &()) {
 903        self.input += &other.input;
 904        self.output += &other.output;
 905    }
 906}
 907
 908#[derive(Clone, Debug)]
 909struct Fold(Range<Anchor>);
 910
 911impl Default for Fold {
 912    fn default() -> Self {
 913        Self(Anchor::min()..Anchor::max())
 914    }
 915}
 916
 917impl sum_tree::Item for Fold {
 918    type Summary = FoldSummary;
 919
 920    fn summary(&self) -> Self::Summary {
 921        FoldSummary {
 922            start: self.0.start.clone(),
 923            end: self.0.end.clone(),
 924            min_start: self.0.start.clone(),
 925            max_end: self.0.end.clone(),
 926            count: 1,
 927        }
 928    }
 929}
 930
 931#[derive(Clone, Debug)]
 932struct FoldSummary {
 933    start: Anchor,
 934    end: Anchor,
 935    min_start: Anchor,
 936    max_end: Anchor,
 937    count: usize,
 938}
 939
 940impl Default for FoldSummary {
 941    fn default() -> Self {
 942        Self {
 943            start: Anchor::min(),
 944            end: Anchor::max(),
 945            min_start: Anchor::max(),
 946            max_end: Anchor::min(),
 947            count: 0,
 948        }
 949    }
 950}
 951
 952impl sum_tree::Summary for FoldSummary {
 953    type Context = MultiBufferSnapshot;
 954
 955    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 956        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
 957            self.min_start = other.min_start.clone();
 958        }
 959        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
 960            self.max_end = other.max_end.clone();
 961        }
 962
 963        #[cfg(debug_assertions)]
 964        {
 965            let start_comparison = self.start.cmp(&other.start, buffer);
 966            assert!(start_comparison <= Ordering::Equal);
 967            if start_comparison == Ordering::Equal {
 968                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
 969            }
 970        }
 971
 972        self.start = other.start.clone();
 973        self.end = other.end.clone();
 974        self.count += other.count;
 975    }
 976}
 977
 978impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 979    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 980        self.0.start = summary.start.clone();
 981        self.0.end = summary.end.clone();
 982    }
 983}
 984
 985impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 986    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 987        self.0.cmp(&other.0, buffer)
 988    }
 989}
 990
 991impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 992    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 993        *self += summary.count;
 994    }
 995}
 996
 997#[derive(Clone)]
 998pub struct FoldBufferRows<'a> {
 999    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
1000    input_buffer_rows: MultiBufferRows<'a>,
1001    fold_point: FoldPoint,
1002}
1003
1004impl<'a> Iterator for FoldBufferRows<'a> {
1005    type Item = Option<u32>;
1006
1007    fn next(&mut self) -> Option<Self::Item> {
1008        let mut traversed_fold = false;
1009        while self.fold_point > self.cursor.end(&()).0 {
1010            self.cursor.next(&());
1011            traversed_fold = true;
1012            if self.cursor.item().is_none() {
1013                break;
1014            }
1015        }
1016
1017        if self.cursor.item().is_some() {
1018            if traversed_fold {
1019                self.input_buffer_rows.seek(self.cursor.start().1.row);
1020                self.input_buffer_rows.next();
1021            }
1022            *self.fold_point.row_mut() += 1;
1023            self.input_buffer_rows.next()
1024        } else {
1025            None
1026        }
1027    }
1028}
1029
1030pub struct FoldChunks<'a> {
1031    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1032    buffer_chunks: MultiBufferChunks<'a>,
1033    buffer_chunk: Option<(usize, Chunk<'a>)>,
1034    buffer_offset: usize,
1035    output_offset: usize,
1036    max_output_offset: usize,
1037    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1038    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1039    ellipses_color: Option<Color>,
1040}
1041
1042impl<'a> Iterator for FoldChunks<'a> {
1043    type Item = Chunk<'a>;
1044
1045    fn next(&mut self) -> Option<Self::Item> {
1046        if self.output_offset >= self.max_output_offset {
1047            return None;
1048        }
1049
1050        let transform = self.transform_cursor.item()?;
1051
1052        // If we're in a fold, then return the fold's display text and
1053        // advance the transform and buffer cursors to the end of the fold.
1054        if let Some(output_text) = transform.output_text {
1055            self.buffer_chunk.take();
1056            self.buffer_offset += transform.summary.input.len;
1057            self.buffer_chunks.seek(self.buffer_offset);
1058
1059            while self.buffer_offset >= self.transform_cursor.end(&()).1
1060                && self.transform_cursor.item().is_some()
1061            {
1062                self.transform_cursor.next(&());
1063            }
1064
1065            self.output_offset += output_text.len();
1066            return Some(Chunk {
1067                text: output_text,
1068                syntax_highlight_id: None,
1069                highlight_style: self.ellipses_color.map(|color| HighlightStyle {
1070                    color: Some(color),
1071                    ..Default::default()
1072                }),
1073                diagnostic_severity: None,
1074                is_unnecessary: false,
1075            });
1076        }
1077
1078        let mut next_highlight_endpoint = usize::MAX;
1079        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1080            if endpoint.offset <= self.buffer_offset {
1081                if endpoint.is_start {
1082                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1083                } else {
1084                    self.active_highlights.remove(&endpoint.tag);
1085                }
1086                self.highlight_endpoints.next();
1087            } else {
1088                next_highlight_endpoint = endpoint.offset;
1089                break;
1090            }
1091        }
1092
1093        // Retrieve a chunk from the current location in the buffer.
1094        if self.buffer_chunk.is_none() {
1095            let chunk_offset = self.buffer_chunks.offset();
1096            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1097        }
1098
1099        // Otherwise, take a chunk from the buffer's text.
1100        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1101            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1102            let transform_end = self.transform_cursor.end(&()).1;
1103            let chunk_end = buffer_chunk_end
1104                .min(transform_end)
1105                .min(next_highlight_endpoint);
1106
1107            chunk.text = &chunk.text
1108                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1109
1110            if !self.active_highlights.is_empty() {
1111                let mut highlight_style = HighlightStyle::default();
1112                for active_highlight in self.active_highlights.values() {
1113                    highlight_style.highlight(*active_highlight);
1114                }
1115                chunk.highlight_style = Some(highlight_style);
1116            }
1117
1118            if chunk_end == transform_end {
1119                self.transform_cursor.next(&());
1120            } else if chunk_end == buffer_chunk_end {
1121                self.buffer_chunk.take();
1122            }
1123
1124            self.buffer_offset = chunk_end;
1125            self.output_offset += chunk.text.len();
1126            return Some(chunk);
1127        }
1128
1129        None
1130    }
1131}
1132
1133#[derive(Copy, Clone, Eq, PartialEq)]
1134struct HighlightEndpoint {
1135    offset: usize,
1136    is_start: bool,
1137    tag: Option<TypeId>,
1138    style: HighlightStyle,
1139}
1140
1141impl PartialOrd for HighlightEndpoint {
1142    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1143        Some(self.cmp(other))
1144    }
1145}
1146
1147impl Ord for HighlightEndpoint {
1148    fn cmp(&self, other: &Self) -> Ordering {
1149        self.offset
1150            .cmp(&other.offset)
1151            .then_with(|| other.is_start.cmp(&self.is_start))
1152    }
1153}
1154
1155#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1156pub struct FoldOffset(pub usize);
1157
1158impl FoldOffset {
1159    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1160        let mut cursor = snapshot
1161            .transforms
1162            .cursor::<(FoldOffset, TransformSummary)>();
1163        cursor.seek(&self, Bias::Right, &());
1164        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1165            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1166        } else {
1167            let buffer_offset = cursor.start().1.input.len + self.0 - cursor.start().0 .0;
1168            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1169            buffer_point - cursor.start().1.input.lines
1170        };
1171        FoldPoint(cursor.start().1.output.lines + overshoot)
1172    }
1173}
1174
1175impl Sub for FoldOffset {
1176    type Output = Self;
1177
1178    fn sub(self, rhs: Self) -> Self::Output {
1179        Self(self.0 - rhs.0)
1180    }
1181}
1182
1183impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1184    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1185        self.0 += &summary.output.len;
1186    }
1187}
1188
1189impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1190    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1191        *self += &summary.input.lines;
1192    }
1193}
1194
1195impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1196    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1197        *self += &summary.input.len;
1198    }
1199}
1200
1201pub type FoldEdit = Edit<FoldOffset>;
1202
1203#[cfg(test)]
1204mod tests {
1205    use super::*;
1206    use crate::{MultiBuffer, ToPoint};
1207    use collections::HashSet;
1208    use rand::prelude::*;
1209    use settings::Settings;
1210    use std::{cmp::Reverse, env, mem, sync::Arc};
1211    use sum_tree::TreeMap;
1212    use util::test::sample_text;
1213    use util::RandomCharIter;
1214    use Bias::{Left, Right};
1215
1216    #[gpui::test]
1217    fn test_basic_folds(cx: &mut gpui::AppContext) {
1218        cx.set_global(Settings::test(cx));
1219        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1220        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1221        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1222        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1223
1224        let (mut writer, _, _) = map.write(buffer_snapshot, vec![]);
1225        let (snapshot2, edits) = writer.fold(vec![
1226            Point::new(0, 2)..Point::new(2, 2),
1227            Point::new(2, 4)..Point::new(4, 1),
1228        ]);
1229        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1230        assert_eq!(
1231            edits,
1232            &[
1233                FoldEdit {
1234                    old: FoldOffset(2)..FoldOffset(16),
1235                    new: FoldOffset(2)..FoldOffset(5),
1236                },
1237                FoldEdit {
1238                    old: FoldOffset(18)..FoldOffset(29),
1239                    new: FoldOffset(7)..FoldOffset(10)
1240                },
1241            ]
1242        );
1243
1244        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1245            buffer.edit(
1246                vec![
1247                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1248                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1249                ],
1250                None,
1251                cx,
1252            );
1253            buffer.snapshot(cx)
1254        });
1255        let (snapshot3, edits) = map.read(buffer_snapshot, subscription.consume().into_inner());
1256        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1257        assert_eq!(
1258            edits,
1259            &[
1260                FoldEdit {
1261                    old: FoldOffset(0)..FoldOffset(1),
1262                    new: FoldOffset(0)..FoldOffset(3),
1263                },
1264                FoldEdit {
1265                    old: FoldOffset(6)..FoldOffset(6),
1266                    new: FoldOffset(8)..FoldOffset(11),
1267                },
1268            ]
1269        );
1270
1271        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1272            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1273            buffer.snapshot(cx)
1274        });
1275        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1276        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1277
1278        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1279        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1280        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1281        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1282
1283        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1284        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1285        let (snapshot6, _) = map.read(buffer_snapshot, vec![]);
1286        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1287    }
1288
1289    #[gpui::test]
1290    fn test_adjacent_folds(cx: &mut gpui::AppContext) {
1291        cx.set_global(Settings::test(cx));
1292        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1293        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1294        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1295
1296        {
1297            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1298
1299            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1300            writer.fold(vec![5..8]);
1301            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1302            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1303
1304            // Create an fold adjacent to the start of the first fold.
1305            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1306            writer.fold(vec![0..1, 2..5]);
1307            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1308            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1309
1310            // Create an fold adjacent to the end of the first fold.
1311            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1312            writer.fold(vec![11..11, 8..10]);
1313            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1314            assert_eq!(snapshot.text(), "⋯b⋯kl");
1315        }
1316
1317        {
1318            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1319
1320            // Create two adjacent folds.
1321            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1322            writer.fold(vec![0..2, 2..5]);
1323            let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1324            assert_eq!(snapshot.text(), "⋯fghijkl");
1325
1326            // Edit within one of the folds.
1327            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1328                buffer.edit([(0..1, "12345")], None, cx);
1329                buffer.snapshot(cx)
1330            });
1331            let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1332            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1333        }
1334    }
1335
1336    #[gpui::test]
1337    fn test_overlapping_folds(cx: &mut gpui::AppContext) {
1338        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1339        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1340        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1341        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1342        writer.fold(vec![
1343            Point::new(0, 2)..Point::new(2, 2),
1344            Point::new(0, 4)..Point::new(1, 0),
1345            Point::new(1, 2)..Point::new(3, 2),
1346            Point::new(3, 1)..Point::new(4, 1),
1347        ]);
1348        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1349        assert_eq!(snapshot.text(), "aa⋯eeeee");
1350    }
1351
1352    #[gpui::test]
1353    fn test_merging_folds_via_edit(cx: &mut gpui::AppContext) {
1354        cx.set_global(Settings::test(cx));
1355        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1356        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1357        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1358        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1359
1360        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1361        writer.fold(vec![
1362            Point::new(0, 2)..Point::new(2, 2),
1363            Point::new(3, 1)..Point::new(4, 1),
1364        ]);
1365        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1366        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1367
1368        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1369            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1370            buffer.snapshot(cx)
1371        });
1372        let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1373        assert_eq!(snapshot.text(), "aa⋯eeeee");
1374    }
1375
1376    #[gpui::test]
1377    fn test_folds_in_range(cx: &mut gpui::AppContext) {
1378        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1379        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1380        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1381
1382        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1383        writer.fold(vec![
1384            Point::new(0, 2)..Point::new(2, 2),
1385            Point::new(0, 4)..Point::new(1, 0),
1386            Point::new(1, 2)..Point::new(3, 2),
1387            Point::new(3, 1)..Point::new(4, 1),
1388        ]);
1389        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1390        let fold_ranges = snapshot
1391            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1392            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1393            .collect::<Vec<_>>();
1394        assert_eq!(
1395            fold_ranges,
1396            vec![
1397                Point::new(0, 2)..Point::new(2, 2),
1398                Point::new(1, 2)..Point::new(3, 2)
1399            ]
1400        );
1401    }
1402
1403    #[gpui::test(iterations = 100)]
1404    fn test_random_folds(cx: &mut gpui::AppContext, mut rng: StdRng) {
1405        cx.set_global(Settings::test(cx));
1406        let operations = env::var("OPERATIONS")
1407            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1408            .unwrap_or(10);
1409
1410        let len = rng.gen_range(0..10);
1411        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1412        let buffer = if rng.gen() {
1413            MultiBuffer::build_simple(&text, cx)
1414        } else {
1415            MultiBuffer::build_random(&mut rng, cx)
1416        };
1417        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1418        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1419
1420        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1421        let mut snapshot_edits = Vec::new();
1422
1423        let mut highlights = TreeMap::default();
1424        let highlight_count = rng.gen_range(0_usize..10);
1425        let mut highlight_ranges = (0..highlight_count)
1426            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1427            .collect::<Vec<_>>();
1428        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1429        log::info!("highlighting ranges {:?}", highlight_ranges);
1430        let highlight_ranges = highlight_ranges
1431            .into_iter()
1432            .map(|range| {
1433                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1434            })
1435            .collect::<Vec<_>>();
1436
1437        highlights.insert(
1438            Some(TypeId::of::<()>()),
1439            Arc::new((HighlightStyle::default(), highlight_ranges)),
1440        );
1441
1442        for _ in 0..operations {
1443            log::info!("text: {:?}", buffer_snapshot.text());
1444            let mut buffer_edits = Vec::new();
1445            match rng.gen_range(0..=100) {
1446                0..=59 => {
1447                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1448                }
1449                _ => buffer.update(cx, |buffer, cx| {
1450                    let subscription = buffer.subscribe();
1451                    let edit_count = rng.gen_range(1..=5);
1452                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1453                    buffer_snapshot = buffer.snapshot(cx);
1454                    let edits = subscription.consume().into_inner();
1455                    log::info!("editing {:?}", edits);
1456                    buffer_edits.extend(edits);
1457                }),
1458            };
1459
1460            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1461            snapshot_edits.push((snapshot.clone(), edits));
1462
1463            let mut expected_text: String = buffer_snapshot.text().to_string();
1464            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1465                expected_text.replace_range(fold_range.start..fold_range.end, "⋯");
1466            }
1467
1468            assert_eq!(snapshot.text(), expected_text);
1469            log::info!(
1470                "fold text {:?} ({} lines)",
1471                expected_text,
1472                expected_text.matches('\n').count() + 1
1473            );
1474
1475            let mut prev_row = 0;
1476            let mut expected_buffer_rows = Vec::new();
1477            for fold_range in map.merged_fold_ranges().into_iter() {
1478                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1479                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1480                expected_buffer_rows.extend(
1481                    buffer_snapshot
1482                        .buffer_rows(prev_row)
1483                        .take((1 + fold_start - prev_row) as usize),
1484                );
1485                prev_row = 1 + fold_end;
1486            }
1487            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1488
1489            assert_eq!(
1490                expected_buffer_rows.len(),
1491                expected_text.matches('\n').count() + 1,
1492                "wrong expected buffer rows {:?}. text: {:?}",
1493                expected_buffer_rows,
1494                expected_text
1495            );
1496
1497            for (output_row, line) in expected_text.lines().enumerate() {
1498                let line_len = snapshot.line_len(output_row as u32);
1499                assert_eq!(line_len, line.len() as u32);
1500            }
1501
1502            let longest_row = snapshot.longest_row();
1503            let longest_char_column = expected_text
1504                .split('\n')
1505                .nth(longest_row as usize)
1506                .unwrap()
1507                .chars()
1508                .count();
1509            let mut fold_point = FoldPoint::new(0, 0);
1510            let mut fold_offset = FoldOffset(0);
1511            let mut char_column = 0;
1512            for c in expected_text.chars() {
1513                let buffer_point = fold_point.to_buffer_point(&snapshot);
1514                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1515                assert_eq!(
1516                    snapshot.to_fold_point(buffer_point, Right),
1517                    fold_point,
1518                    "{:?} -> fold point",
1519                    buffer_point,
1520                );
1521                assert_eq!(
1522                    fold_point.to_buffer_offset(&snapshot),
1523                    buffer_offset,
1524                    "fold_point.to_buffer_offset({:?})",
1525                    fold_point,
1526                );
1527                assert_eq!(
1528                    fold_point.to_offset(&snapshot),
1529                    fold_offset,
1530                    "fold_point.to_offset({:?})",
1531                    fold_point,
1532                );
1533
1534                if c == '\n' {
1535                    *fold_point.row_mut() += 1;
1536                    *fold_point.column_mut() = 0;
1537                    char_column = 0;
1538                } else {
1539                    *fold_point.column_mut() += c.len_utf8() as u32;
1540                    char_column += 1;
1541                }
1542                fold_offset.0 += c.len_utf8();
1543                if char_column > longest_char_column {
1544                    panic!(
1545                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1546                        longest_row,
1547                        longest_char_column,
1548                        fold_point.row(),
1549                        char_column
1550                    );
1551                }
1552            }
1553
1554            for _ in 0..5 {
1555                let mut start = snapshot
1556                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1557                let mut end = snapshot
1558                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1559                if start > end {
1560                    mem::swap(&mut start, &mut end);
1561                }
1562
1563                let text = &expected_text[start.0..end.0];
1564                assert_eq!(
1565                    snapshot
1566                        .chunks(start..end, false, Some(&highlights))
1567                        .map(|c| c.text)
1568                        .collect::<String>(),
1569                    text,
1570                );
1571            }
1572
1573            let mut fold_row = 0;
1574            while fold_row < expected_buffer_rows.len() as u32 {
1575                fold_row = snapshot
1576                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1577                    .row();
1578                assert_eq!(
1579                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1580                    expected_buffer_rows[(fold_row as usize)..],
1581                    "wrong buffer rows starting at fold row {}",
1582                    fold_row,
1583                );
1584                fold_row += 1;
1585            }
1586
1587            let fold_start_rows = map
1588                .merged_fold_ranges()
1589                .iter()
1590                .map(|range| range.start.to_point(&buffer_snapshot).row)
1591                .collect::<HashSet<_>>();
1592            for row in fold_start_rows {
1593                assert!(snapshot.is_line_folded(row));
1594            }
1595
1596            for _ in 0..5 {
1597                let end =
1598                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1599                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1600                let expected_folds = map
1601                    .folds
1602                    .items(&buffer_snapshot)
1603                    .into_iter()
1604                    .filter(|fold| {
1605                        let start = buffer_snapshot.anchor_before(start);
1606                        let end = buffer_snapshot.anchor_after(end);
1607                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1608                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1609                    })
1610                    .map(|fold| fold.0)
1611                    .collect::<Vec<_>>();
1612
1613                assert_eq!(
1614                    snapshot
1615                        .folds_in_range(start..end)
1616                        .cloned()
1617                        .collect::<Vec<_>>(),
1618                    expected_folds
1619                );
1620            }
1621
1622            let text = snapshot.text();
1623            for _ in 0..5 {
1624                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1625                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1626                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1627                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1628                let mut start =
1629                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1630                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1631                if start > end {
1632                    mem::swap(&mut start, &mut end);
1633                }
1634
1635                let lines = start..end;
1636                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1637                assert_eq!(
1638                    snapshot.text_summary_for_range(lines),
1639                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1640                )
1641            }
1642
1643            let mut text = initial_snapshot.text();
1644            for (snapshot, edits) in snapshot_edits.drain(..) {
1645                let new_text = snapshot.text();
1646                for edit in edits {
1647                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1648                    let new_bytes = edit.new.start.0..edit.new.end.0;
1649                    text.replace_range(old_bytes, &new_text[new_bytes]);
1650                }
1651
1652                assert_eq!(text, new_text);
1653                initial_snapshot = snapshot;
1654            }
1655        }
1656    }
1657
1658    #[gpui::test]
1659    fn test_buffer_rows(cx: &mut gpui::AppContext) {
1660        let text = sample_text(6, 6, 'a') + "\n";
1661        let buffer = MultiBuffer::build_simple(&text, cx);
1662
1663        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1664        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1665
1666        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1667        writer.fold(vec![
1668            Point::new(0, 2)..Point::new(2, 2),
1669            Point::new(3, 1)..Point::new(4, 1),
1670        ]);
1671
1672        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1673        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
1674        assert_eq!(
1675            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1676            [Some(0), Some(3), Some(5), Some(6)]
1677        );
1678        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1679    }
1680
1681    impl FoldMap {
1682        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1683            let buffer = self.buffer.lock().clone();
1684            let mut folds = self.folds.items(&buffer);
1685            // Ensure sorting doesn't change how folds get merged and displayed.
1686            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer));
1687            let mut fold_ranges = folds
1688                .iter()
1689                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1690                .peekable();
1691
1692            let mut merged_ranges = Vec::new();
1693            while let Some(mut fold_range) = fold_ranges.next() {
1694                while let Some(next_range) = fold_ranges.peek() {
1695                    if fold_range.end >= next_range.start {
1696                        if next_range.end > fold_range.end {
1697                            fold_range.end = next_range.end;
1698                        }
1699                        fold_ranges.next();
1700                    } else {
1701                        break;
1702                    }
1703                }
1704                if fold_range.end > fold_range.start {
1705                    merged_ranges.push(fold_range);
1706                }
1707            }
1708            merged_ranges
1709        }
1710
1711        pub fn randomly_mutate(
1712            &mut self,
1713            rng: &mut impl Rng,
1714        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1715            let mut snapshot_edits = Vec::new();
1716            match rng.gen_range(0..=100) {
1717                0..=39 if !self.folds.is_empty() => {
1718                    let buffer = self.buffer.lock().clone();
1719                    let mut to_unfold = Vec::new();
1720                    for _ in 0..rng.gen_range(1..=3) {
1721                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1722                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1723                        to_unfold.push(start..end);
1724                    }
1725                    log::info!("unfolding {:?}", to_unfold);
1726                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1727                    snapshot_edits.push((snapshot, edits));
1728                    let (snapshot, edits) = writer.fold(to_unfold);
1729                    snapshot_edits.push((snapshot, edits));
1730                }
1731                _ => {
1732                    let buffer = self.buffer.lock().clone();
1733                    let mut to_fold = Vec::new();
1734                    for _ in 0..rng.gen_range(1..=2) {
1735                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1736                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1737                        to_fold.push(start..end);
1738                    }
1739                    log::info!("folding {:?}", to_fold);
1740                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1741                    snapshot_edits.push((snapshot, edits));
1742                    let (snapshot, edits) = writer.fold(to_fold);
1743                    snapshot_edits.push((snapshot, edits));
1744                }
1745            }
1746            snapshot_edits
1747        }
1748    }
1749}