fold_map.rs

   1use super::{
   2    inlay_map::{InlayEdit, InlayOffset, InlayPoint, InlaySnapshot},
   3    TextHighlights,
   4};
   5use crate::{
   6    multi_buffer::{MultiBufferChunks, MultiBufferRows},
   7    Anchor, AnchorRangeExt, MultiBufferSnapshot, ToOffset,
   8};
   9use collections::BTreeMap;
  10use gpui::{color::Color, fonts::HighlightStyle};
  11use language::{Chunk, Edit, Point, TextSummary};
  12use parking_lot::Mutex;
  13use std::{
  14    any::TypeId,
  15    cmp::{self, Ordering},
  16    iter::{self, Peekable},
  17    ops::{Add, AddAssign, Range, Sub},
  18    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  19    vec,
  20};
  21use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  22
  23#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  24pub struct FoldPoint(pub Point);
  25
  26impl FoldPoint {
  27    pub fn new(row: u32, column: u32) -> Self {
  28        Self(Point::new(row, column))
  29    }
  30
  31    pub fn row(self) -> u32 {
  32        self.0.row
  33    }
  34
  35    pub fn column(self) -> u32 {
  36        self.0.column
  37    }
  38
  39    pub fn row_mut(&mut self) -> &mut u32 {
  40        &mut self.0.row
  41    }
  42
  43    pub fn column_mut(&mut self) -> &mut u32 {
  44        &mut self.0.column
  45    }
  46
  47    pub fn to_inlay_point(self, snapshot: &FoldSnapshot) -> InlayPoint {
  48        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, InlayPoint)>();
  49        cursor.seek(&self, Bias::Right, &());
  50        let overshoot = self.0 - cursor.start().0 .0;
  51        InlayPoint(cursor.start().1 .0 + overshoot)
  52    }
  53
  54    pub fn to_inlay_offset(self, snapshot: &FoldSnapshot) -> InlayOffset {
  55        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, InlayPoint)>();
  56        cursor.seek(&self, Bias::Right, &());
  57        let overshoot = self.0 - cursor.start().0 .0;
  58        snapshot
  59            .inlay_snapshot
  60            .to_offset(InlayPoint(cursor.start().1 .0 + overshoot))
  61    }
  62
  63    pub fn to_offset(self, snapshot: &FoldSnapshot) -> FoldOffset {
  64        let mut cursor = snapshot
  65            .transforms
  66            .cursor::<(FoldPoint, TransformSummary)>();
  67        cursor.seek(&self, Bias::Right, &());
  68        let inlay_snapshot = &snapshot.inlay_snapshot;
  69        let to_inlay_offset = |buffer_offset: usize| {
  70            let buffer_point = inlay_snapshot.buffer.offset_to_point(buffer_offset);
  71            inlay_snapshot.to_offset(inlay_snapshot.to_inlay_point(buffer_point))
  72        };
  73        let mut inlay_offset = to_inlay_offset(cursor.start().1.output.len);
  74        let overshoot = self.0 - cursor.start().1.output.lines;
  75        if !overshoot.is_zero() {
  76            let transform = cursor.item().expect("display point out of range");
  77            assert!(transform.output_text.is_none());
  78            let end_snapshot_offset = snapshot
  79                .inlay_snapshot
  80                .to_offset(InlayPoint(cursor.start().1.input.lines + overshoot));
  81            inlay_offset += end_snapshot_offset - to_inlay_offset(cursor.start().1.input.len);
  82        }
  83
  84        snapshot
  85            .to_fold_point(inlay_snapshot.to_point(inlay_offset), Bias::Right)
  86            .to_offset(snapshot)
  87    }
  88}
  89
  90impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
  91    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
  92        self.0 += &summary.output.lines;
  93    }
  94}
  95
  96pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  97
  98impl<'a> FoldMapWriter<'a> {
  99    pub fn fold<T: ToOffset>(
 100        &mut self,
 101        ranges: impl IntoIterator<Item = Range<T>>,
 102    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 103        let mut edits = Vec::new();
 104        let mut folds = Vec::new();
 105        let snapshot = self.0.inlay_snapshot.lock().clone();
 106        for range in ranges.into_iter() {
 107            let buffer = &snapshot.buffer;
 108            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 109
 110            // Ignore any empty ranges.
 111            if range.start == range.end {
 112                continue;
 113            }
 114
 115            // For now, ignore any ranges that span an excerpt boundary.
 116            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 117            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 118                continue;
 119            }
 120
 121            folds.push(fold);
 122
 123            let inlay_range =
 124                snapshot.to_inlay_offset(range.start)..snapshot.to_inlay_offset(range.end);
 125            edits.push(InlayEdit {
 126                old: inlay_range.clone(),
 127                new: inlay_range,
 128            });
 129        }
 130
 131        let buffer = &snapshot.buffer;
 132        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, buffer));
 133
 134        self.0.folds = {
 135            let mut new_tree = SumTree::new();
 136            let mut cursor = self.0.folds.cursor::<Fold>();
 137            for fold in folds {
 138                new_tree.append(cursor.slice(&fold, Bias::Right, buffer), buffer);
 139                new_tree.push(fold, buffer);
 140            }
 141            new_tree.append(cursor.suffix(buffer), buffer);
 142            new_tree
 143        };
 144
 145        consolidate_inlay_edits(&mut edits);
 146        let edits = self.0.sync(snapshot.clone(), edits);
 147        let snapshot = FoldSnapshot {
 148            transforms: self.0.transforms.lock().clone(),
 149            folds: self.0.folds.clone(),
 150            inlay_snapshot: snapshot,
 151            version: self.0.version.load(SeqCst),
 152            ellipses_color: self.0.ellipses_color,
 153        };
 154        (snapshot, edits)
 155    }
 156
 157    pub fn unfold<T: ToOffset>(
 158        &mut self,
 159        ranges: impl IntoIterator<Item = Range<T>>,
 160        inclusive: bool,
 161    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 162        let mut edits = Vec::new();
 163        let mut fold_ixs_to_delete = Vec::new();
 164        let snapshot = self.0.inlay_snapshot.lock().clone();
 165        let buffer = &snapshot.buffer;
 166        for range in ranges.into_iter() {
 167            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 168            let mut folds_cursor = intersecting_folds(&snapshot, &self.0.folds, range, inclusive);
 169            while let Some(fold) = folds_cursor.item() {
 170                let offset_range = fold.0.start.to_offset(buffer)..fold.0.end.to_offset(buffer);
 171                if offset_range.end > offset_range.start {
 172                    let inlay_range = snapshot.to_inlay_offset(offset_range.start)
 173                        ..snapshot.to_inlay_offset(offset_range.end);
 174                    edits.push(InlayEdit {
 175                        old: inlay_range.clone(),
 176                        new: inlay_range,
 177                    });
 178                }
 179                fold_ixs_to_delete.push(*folds_cursor.start());
 180                folds_cursor.next(buffer);
 181            }
 182        }
 183
 184        fold_ixs_to_delete.sort_unstable();
 185        fold_ixs_to_delete.dedup();
 186
 187        self.0.folds = {
 188            let mut cursor = self.0.folds.cursor::<usize>();
 189            let mut folds = SumTree::new();
 190            for fold_ix in fold_ixs_to_delete {
 191                folds.append(cursor.slice(&fold_ix, Bias::Right, buffer), buffer);
 192                cursor.next(buffer);
 193            }
 194            folds.append(cursor.suffix(buffer), buffer);
 195            folds
 196        };
 197
 198        consolidate_inlay_edits(&mut edits);
 199        let edits = self.0.sync(snapshot.clone(), edits);
 200        let snapshot = FoldSnapshot {
 201            transforms: self.0.transforms.lock().clone(),
 202            folds: self.0.folds.clone(),
 203            inlay_snapshot: snapshot,
 204            version: self.0.version.load(SeqCst),
 205            ellipses_color: self.0.ellipses_color,
 206        };
 207        (snapshot, edits)
 208    }
 209}
 210
 211pub struct FoldMap {
 212    inlay_snapshot: Mutex<InlaySnapshot>,
 213    transforms: Mutex<SumTree<Transform>>,
 214    folds: SumTree<Fold>,
 215    version: AtomicUsize,
 216    ellipses_color: Option<Color>,
 217}
 218
 219impl FoldMap {
 220    pub fn new(inlay_snapshot: InlaySnapshot) -> (Self, FoldSnapshot) {
 221        let this = Self {
 222            inlay_snapshot: Mutex::new(inlay_snapshot.clone()),
 223            folds: Default::default(),
 224            transforms: Mutex::new(SumTree::from_item(
 225                Transform {
 226                    summary: TransformSummary {
 227                        input: inlay_snapshot.text_summary(),
 228                        output: inlay_snapshot.text_summary(),
 229                    },
 230                    output_text: None,
 231                },
 232                &(),
 233            )),
 234            ellipses_color: None,
 235            version: Default::default(),
 236        };
 237
 238        let snapshot = FoldSnapshot {
 239            transforms: this.transforms.lock().clone(),
 240            folds: this.folds.clone(),
 241            inlay_snapshot: inlay_snapshot.clone(),
 242            version: this.version.load(SeqCst),
 243            ellipses_color: None,
 244        };
 245        (this, snapshot)
 246    }
 247
 248    pub fn read(
 249        &self,
 250        inlay_snapshot: InlaySnapshot,
 251        edits: Vec<InlayEdit>,
 252    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 253        let edits = self.sync(inlay_snapshot, edits);
 254        self.check_invariants();
 255        let snapshot = FoldSnapshot {
 256            transforms: self.transforms.lock().clone(),
 257            folds: self.folds.clone(),
 258            inlay_snapshot: self.inlay_snapshot.lock().clone(),
 259            version: self.version.load(SeqCst),
 260            ellipses_color: self.ellipses_color,
 261        };
 262        (snapshot, edits)
 263    }
 264
 265    pub fn write(
 266        &mut self,
 267        inlay_snapshot: InlaySnapshot,
 268        edits: Vec<InlayEdit>,
 269    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 270        let (snapshot, edits) = self.read(inlay_snapshot, edits);
 271        (FoldMapWriter(self), snapshot, edits)
 272    }
 273
 274    pub fn set_ellipses_color(&mut self, color: Color) -> bool {
 275        if self.ellipses_color != Some(color) {
 276            self.ellipses_color = Some(color);
 277            true
 278        } else {
 279            false
 280        }
 281    }
 282
 283    fn check_invariants(&self) {
 284        if cfg!(test) {
 285            let inlay_snapshot = self.inlay_snapshot.lock();
 286            assert_eq!(
 287                self.transforms.lock().summary().input.len,
 288                inlay_snapshot.to_buffer_offset(inlay_snapshot.len()),
 289                "transform tree does not match inlay snapshot's length"
 290            );
 291
 292            let mut folds = self.folds.iter().peekable();
 293            while let Some(fold) = folds.next() {
 294                if let Some(next_fold) = folds.peek() {
 295                    let comparison = fold.0.cmp(&next_fold.0, &self.inlay_snapshot.lock().buffer);
 296                    assert!(comparison.is_le());
 297                }
 298            }
 299        }
 300    }
 301
 302    fn sync(&self, inlay_snapshot: InlaySnapshot, inlay_edits: Vec<InlayEdit>) -> Vec<FoldEdit> {
 303        let buffer = &inlay_snapshot.buffer;
 304        let snapshot = self.inlay_snapshot.lock();
 305
 306        let mut new_snapshot = snapshot.clone();
 307        if new_snapshot.version != inlay_snapshot.version {
 308            new_snapshot.version += 1;
 309        }
 310
 311        let mut inlay_edits_iter = inlay_edits.iter().cloned().peekable();
 312
 313        let mut new_transforms = SumTree::new();
 314        let mut transforms = self.transforms.lock();
 315        let mut cursor = transforms.cursor::<usize>();
 316        cursor.seek(&0, Bias::Right, &());
 317
 318        while let Some(inlay_edit) = inlay_edits_iter.next() {
 319            // TODO kb is this right?
 320            let mut edit = Edit {
 321                old: inlay_snapshot.to_buffer_offset(inlay_edit.old.start)
 322                    ..inlay_snapshot.to_buffer_offset(inlay_edit.old.end),
 323                new: inlay_snapshot.to_buffer_offset(inlay_edit.new.start)
 324                    ..inlay_snapshot.to_buffer_offset(inlay_edit.new.end),
 325            };
 326            new_transforms.append(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 327            edit.new.start -= edit.old.start - cursor.start();
 328            edit.old.start = *cursor.start();
 329
 330            cursor.seek(&edit.old.end, Bias::Right, &());
 331            cursor.next(&());
 332
 333            let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 334            loop {
 335                edit.old.end = *cursor.start();
 336
 337                if let Some(next_inlay_edit) = inlay_edits_iter.peek() {
 338                    if next_inlay_edit.old.start > inlay_snapshot.to_inlay_offset(edit.old.end) {
 339                        break;
 340                    }
 341
 342                    let next_inlay_edit = inlay_edits_iter.next().unwrap();
 343                    let next_edit = Edit {
 344                        old: inlay_snapshot.to_buffer_offset(next_inlay_edit.old.start)
 345                            ..inlay_snapshot.to_buffer_offset(next_inlay_edit.old.end),
 346                        new: inlay_snapshot.to_buffer_offset(next_inlay_edit.new.start)
 347                            ..inlay_snapshot.to_buffer_offset(next_inlay_edit.new.end),
 348                    };
 349                    delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 350
 351                    if next_edit.old.end >= edit.old.end {
 352                        edit.old.end = next_edit.old.end;
 353                        cursor.seek(&edit.old.end, Bias::Right, &());
 354                        cursor.next(&());
 355                    }
 356                } else {
 357                    break;
 358                }
 359            }
 360
 361            edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 362
 363            let anchor = buffer.anchor_before(edit.new.start);
 364            let mut folds_cursor = self.folds.cursor::<Fold>();
 365            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 366
 367            let mut folds = iter::from_fn({
 368                || {
 369                    let item = folds_cursor.item().map(|f| {
 370                        let fold_buffer_start = f.0.start.to_offset(buffer);
 371                        let fold_buffer_end = f.0.end.to_offset(buffer);
 372
 373                        inlay_snapshot.to_inlay_offset(fold_buffer_start)
 374                            ..inlay_snapshot.to_inlay_offset(fold_buffer_end)
 375                    });
 376                    folds_cursor.next(buffer);
 377                    item
 378                }
 379            })
 380            .peekable();
 381
 382            while folds.peek().map_or(false, |fold| {
 383                inlay_snapshot.to_buffer_offset(fold.start) < edit.new.end
 384            }) {
 385                let mut fold = folds.next().unwrap();
 386                let sum = new_transforms.summary();
 387
 388                assert!(inlay_snapshot.to_buffer_offset(fold.start) >= sum.input.len);
 389
 390                while folds
 391                    .peek()
 392                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 393                {
 394                    let next_fold = folds.next().unwrap();
 395                    if next_fold.end > fold.end {
 396                        fold.end = next_fold.end;
 397                    }
 398                }
 399
 400                if inlay_snapshot.to_buffer_offset(fold.start) > sum.input.len {
 401                    let text_summary = buffer.text_summary_for_range::<TextSummary, _>(
 402                        sum.input.len..inlay_snapshot.to_buffer_offset(fold.start),
 403                    );
 404                    new_transforms.push(
 405                        Transform {
 406                            summary: TransformSummary {
 407                                output: text_summary.clone(),
 408                                input: text_summary,
 409                            },
 410                            output_text: None,
 411                        },
 412                        &(),
 413                    );
 414                }
 415
 416                if fold.end > fold.start {
 417                    let output_text = "";
 418                    new_transforms.push(
 419                        Transform {
 420                            summary: TransformSummary {
 421                                output: TextSummary::from(output_text),
 422                                input: inlay_snapshot.text_summary_for_range(
 423                                    inlay_snapshot.to_point(fold.start)
 424                                        ..inlay_snapshot.to_point(fold.end),
 425                                ),
 426                            },
 427                            output_text: Some(output_text),
 428                        },
 429                        &(),
 430                    );
 431                }
 432            }
 433
 434            let sum = new_transforms.summary();
 435            if sum.input.len < edit.new.end {
 436                let text_summary: TextSummary =
 437                    buffer.text_summary_for_range(sum.input.len..edit.new.end);
 438                new_transforms.push(
 439                    Transform {
 440                        summary: TransformSummary {
 441                            output: text_summary.clone(),
 442                            input: text_summary,
 443                        },
 444                        output_text: None,
 445                    },
 446                    &(),
 447                );
 448            }
 449        }
 450
 451        new_transforms.append(cursor.suffix(&()), &());
 452        if new_transforms.is_empty() {
 453            let text_summary = inlay_snapshot.text_summary();
 454            new_transforms.push(
 455                Transform {
 456                    summary: TransformSummary {
 457                        output: text_summary.clone(),
 458                        input: text_summary,
 459                    },
 460                    output_text: None,
 461                },
 462                &(),
 463            );
 464        }
 465
 466        drop(cursor);
 467
 468        let mut fold_edits = Vec::with_capacity(inlay_edits.len());
 469        {
 470            let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 471            let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 472
 473            for inlay_edit in inlay_edits {
 474                let mut edit = Edit {
 475                    old: inlay_snapshot.to_buffer_offset(inlay_edit.old.start)
 476                        ..inlay_snapshot.to_buffer_offset(inlay_edit.old.end),
 477                    new: inlay_snapshot.to_buffer_offset(inlay_edit.new.start)
 478                        ..inlay_snapshot.to_buffer_offset(inlay_edit.new.end),
 479                };
 480                old_transforms.seek(&edit.old.start, Bias::Left, &());
 481                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 482                    edit.old.start = old_transforms.start().0;
 483                }
 484                let old_start =
 485                    old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 486
 487                old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 488                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 489                    old_transforms.next(&());
 490                    edit.old.end = old_transforms.start().0;
 491                }
 492                let old_end =
 493                    old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 494
 495                new_transforms.seek(&edit.new.start, Bias::Left, &());
 496                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 497                    edit.new.start = new_transforms.start().0;
 498                }
 499                let new_start =
 500                    new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 501
 502                new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 503                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 504                    new_transforms.next(&());
 505                    edit.new.end = new_transforms.start().0;
 506                }
 507                let new_end =
 508                    new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 509
 510                fold_edits.push(FoldEdit {
 511                    old: FoldOffset(old_start)..FoldOffset(old_end),
 512                    new: FoldOffset(new_start)..FoldOffset(new_end),
 513                });
 514            }
 515
 516            consolidate_fold_edits(&mut fold_edits);
 517        }
 518
 519        *transforms = new_transforms;
 520        *self.inlay_snapshot.lock() = inlay_snapshot;
 521        self.version.fetch_add(1, SeqCst);
 522        fold_edits
 523    }
 524}
 525
 526#[derive(Clone)]
 527pub struct FoldSnapshot {
 528    transforms: SumTree<Transform>,
 529    folds: SumTree<Fold>,
 530    pub inlay_snapshot: InlaySnapshot,
 531    pub version: usize,
 532    pub ellipses_color: Option<Color>,
 533}
 534
 535impl FoldSnapshot {
 536    #[cfg(test)]
 537    pub fn text(&self) -> String {
 538        self.chunks(FoldOffset(0)..self.len(), false, None, None)
 539            .map(|c| c.text)
 540            .collect()
 541    }
 542
 543    #[cfg(test)]
 544    pub fn fold_count(&self) -> usize {
 545        self.folds.items(&self.inlay_snapshot.buffer).len()
 546    }
 547
 548    pub fn text_summary(&self) -> TextSummary {
 549        self.transforms.summary().output.clone()
 550    }
 551
 552    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 553        let mut summary = TextSummary::default();
 554
 555        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 556        cursor.seek(&range.start, Bias::Right, &());
 557        if let Some(transform) = cursor.item() {
 558            let start_in_transform = range.start.0 - cursor.start().0 .0;
 559            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 560            if let Some(output_text) = transform.output_text {
 561                summary = TextSummary::from(
 562                    &output_text
 563                        [start_in_transform.column as usize..end_in_transform.column as usize],
 564                );
 565            } else {
 566                let buffer_start = cursor.start().1 + start_in_transform;
 567                let buffer_end = cursor.start().1 + end_in_transform;
 568                summary = self
 569                    .inlay_snapshot
 570                    .buffer
 571                    .text_summary_for_range(buffer_start..buffer_end);
 572            }
 573        }
 574
 575        if range.end > cursor.end(&()).0 {
 576            cursor.next(&());
 577            summary += &cursor
 578                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 579                .output;
 580            if let Some(transform) = cursor.item() {
 581                let end_in_transform = range.end.0 - cursor.start().0 .0;
 582                if let Some(output_text) = transform.output_text {
 583                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 584                } else {
 585                    let buffer_start = cursor.start().1;
 586                    let buffer_end = cursor.start().1 + end_in_transform;
 587                    summary += self
 588                        .inlay_snapshot
 589                        .buffer
 590                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 591                }
 592            }
 593        }
 594
 595        summary
 596    }
 597
 598    pub fn to_fold_point(&self, point: InlayPoint, bias: Bias) -> FoldPoint {
 599        let mut cursor = self.transforms.cursor::<(InlayPoint, FoldPoint)>();
 600        cursor.seek(&point, Bias::Right, &());
 601        if cursor.item().map_or(false, |t| t.is_fold()) {
 602            if bias == Bias::Left || point == cursor.start().0 {
 603                cursor.start().1
 604            } else {
 605                cursor.end(&()).1
 606            }
 607        } else {
 608            let overshoot = InlayPoint(point.0 - cursor.start().0 .0);
 609            // TODO kb is this right?
 610            cmp::min(
 611                FoldPoint(cursor.start().1 .0 + overshoot.0),
 612                cursor.end(&()).1,
 613            )
 614        }
 615    }
 616
 617    pub fn len(&self) -> FoldOffset {
 618        FoldOffset(self.transforms.summary().output.len)
 619    }
 620
 621    pub fn line_len(&self, row: u32) -> u32 {
 622        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 623        let line_end = if row >= self.max_point().row() {
 624            self.len().0
 625        } else {
 626            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 627        };
 628        (line_end - line_start) as u32
 629    }
 630
 631    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 632        if start_row > self.transforms.summary().output.lines.row {
 633            panic!("invalid display row {}", start_row);
 634        }
 635
 636        let fold_point = FoldPoint::new(start_row, 0);
 637        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 638        cursor.seek(&fold_point, Bias::Left, &());
 639
 640        let overshoot = fold_point.0 - cursor.start().0 .0;
 641        let buffer_point = cursor.start().1 + overshoot;
 642        let input_buffer_rows = self.inlay_snapshot.buffer.buffer_rows(buffer_point.row);
 643
 644        FoldBufferRows {
 645            fold_point,
 646            input_buffer_rows,
 647            cursor,
 648        }
 649    }
 650
 651    pub fn max_point(&self) -> FoldPoint {
 652        FoldPoint(self.transforms.summary().output.lines)
 653    }
 654
 655    #[cfg(test)]
 656    pub fn longest_row(&self) -> u32 {
 657        self.transforms.summary().output.longest_row
 658    }
 659
 660    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Range<Anchor>>
 661    where
 662        T: ToOffset,
 663    {
 664        let mut folds = intersecting_folds(&self.inlay_snapshot, &self.folds, range, false);
 665        iter::from_fn(move || {
 666            let item = folds.item().map(|f| &f.0);
 667            folds.next(&self.inlay_snapshot.buffer);
 668            item
 669        })
 670    }
 671
 672    pub fn intersects_fold<T>(&self, offset: T) -> bool
 673    where
 674        T: ToOffset,
 675    {
 676        let offset = offset.to_offset(&self.inlay_snapshot.buffer);
 677        let mut cursor = self.transforms.cursor::<usize>();
 678        cursor.seek(&offset, Bias::Right, &());
 679        cursor.item().map_or(false, |t| t.output_text.is_some())
 680    }
 681
 682    pub fn is_line_folded(&self, buffer_row: u32) -> bool {
 683        let mut cursor = self.transforms.cursor::<Point>();
 684        // TODO kb is this right?
 685        cursor.seek(&Point::new(buffer_row, 0), Bias::Right, &());
 686        while let Some(transform) = cursor.item() {
 687            if transform.output_text.is_some() {
 688                return true;
 689            }
 690            if cursor.end(&()).row == buffer_row {
 691                cursor.next(&())
 692            } else {
 693                break;
 694            }
 695        }
 696        false
 697    }
 698
 699    pub fn chunks<'a>(
 700        &'a self,
 701        range: Range<FoldOffset>,
 702        language_aware: bool,
 703        text_highlights: Option<&'a TextHighlights>,
 704        // TODO kb need to call inlay chunks and style them
 705        inlay_highlights: Option<HighlightStyle>,
 706    ) -> FoldChunks<'a> {
 707        let mut highlight_endpoints = Vec::new();
 708        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 709
 710        let buffer_end = {
 711            transform_cursor.seek(&range.end, Bias::Right, &());
 712            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 713            transform_cursor.start().1 + overshoot
 714        };
 715
 716        let buffer_start = {
 717            transform_cursor.seek(&range.start, Bias::Right, &());
 718            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 719            transform_cursor.start().1 + overshoot
 720        };
 721
 722        if let Some(text_highlights) = text_highlights {
 723            if !text_highlights.is_empty() {
 724                while transform_cursor.start().0 < range.end {
 725                    if !transform_cursor.item().unwrap().is_fold() {
 726                        let transform_start = self
 727                            .inlay_snapshot
 728                            .buffer
 729                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 730
 731                        let transform_end = {
 732                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 733                            self.inlay_snapshot.buffer.anchor_before(cmp::min(
 734                                transform_cursor.end(&()).1,
 735                                transform_cursor.start().1 + overshoot,
 736                            ))
 737                        };
 738
 739                        for (tag, highlights) in text_highlights.iter() {
 740                            let style = highlights.0;
 741                            let ranges = &highlights.1;
 742
 743                            let start_ix = match ranges.binary_search_by(|probe| {
 744                                let cmp =
 745                                    probe.end.cmp(&transform_start, &self.inlay_snapshot.buffer);
 746                                if cmp.is_gt() {
 747                                    Ordering::Greater
 748                                } else {
 749                                    Ordering::Less
 750                                }
 751                            }) {
 752                                Ok(i) | Err(i) => i,
 753                            };
 754                            for range in &ranges[start_ix..] {
 755                                if range
 756                                    .start
 757                                    .cmp(&transform_end, &self.inlay_snapshot.buffer)
 758                                    .is_ge()
 759                                {
 760                                    break;
 761                                }
 762
 763                                highlight_endpoints.push(HighlightEndpoint {
 764                                    offset: range.start.to_offset(&self.inlay_snapshot.buffer),
 765                                    is_start: true,
 766                                    tag: *tag,
 767                                    style,
 768                                });
 769                                highlight_endpoints.push(HighlightEndpoint {
 770                                    offset: range.end.to_offset(&self.inlay_snapshot.buffer),
 771                                    is_start: false,
 772                                    tag: *tag,
 773                                    style,
 774                                });
 775                            }
 776                        }
 777                    }
 778
 779                    transform_cursor.next(&());
 780                }
 781                highlight_endpoints.sort();
 782                transform_cursor.seek(&range.start, Bias::Right, &());
 783            }
 784        }
 785
 786        FoldChunks {
 787            transform_cursor,
 788            buffer_chunks: self
 789                .inlay_snapshot
 790                .buffer
 791                .chunks(buffer_start..buffer_end, language_aware),
 792            inlay_chunk: None,
 793            buffer_offset: buffer_start,
 794            output_offset: range.start.0,
 795            max_output_offset: range.end.0,
 796            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 797            active_highlights: Default::default(),
 798            ellipses_color: self.ellipses_color,
 799        }
 800    }
 801
 802    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 803        self.chunks(start.to_offset(self)..self.len(), false, None, None)
 804            .flat_map(|chunk| chunk.text.chars())
 805    }
 806
 807    #[cfg(test)]
 808    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 809        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 810        cursor.seek(&offset, Bias::Right, &());
 811        if let Some(transform) = cursor.item() {
 812            let transform_start = cursor.start().0 .0;
 813            if transform.output_text.is_some() {
 814                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 815                    FoldOffset(transform_start)
 816                } else {
 817                    FoldOffset(cursor.end(&()).0 .0)
 818                }
 819            } else {
 820                let overshoot = offset.0 - transform_start;
 821                let buffer_offset = cursor.start().1 + overshoot;
 822                let clipped_buffer_offset =
 823                    self.inlay_snapshot.buffer.clip_offset(buffer_offset, bias);
 824                FoldOffset(
 825                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 826                        as usize,
 827                )
 828            }
 829        } else {
 830            FoldOffset(self.transforms.summary().output.len)
 831        }
 832    }
 833
 834    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 835        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 836        cursor.seek(&point, Bias::Right, &());
 837        if let Some(transform) = cursor.item() {
 838            let transform_start = cursor.start().0 .0;
 839            if transform.output_text.is_some() {
 840                if point.0 == transform_start || matches!(bias, Bias::Left) {
 841                    FoldPoint(transform_start)
 842                } else {
 843                    FoldPoint(cursor.end(&()).0 .0)
 844                }
 845            } else {
 846                let overshoot = point.0 - transform_start;
 847                let buffer_position = cursor.start().1 + overshoot;
 848                let clipped_buffer_position =
 849                    self.inlay_snapshot.buffer.clip_point(buffer_position, bias);
 850                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 851            }
 852        } else {
 853            FoldPoint(self.transforms.summary().output.lines)
 854        }
 855    }
 856}
 857
 858fn intersecting_folds<'a, T>(
 859    inlay_snapshot: &'a InlaySnapshot,
 860    folds: &'a SumTree<Fold>,
 861    range: Range<T>,
 862    inclusive: bool,
 863) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 864where
 865    T: ToOffset,
 866{
 867    let buffer = &inlay_snapshot.buffer;
 868    let start = buffer.anchor_before(range.start.to_offset(buffer));
 869    let end = buffer.anchor_after(range.end.to_offset(buffer));
 870    let mut cursor = folds.filter::<_, usize>(move |summary| {
 871        let start_cmp = start.cmp(&summary.max_end, buffer);
 872        let end_cmp = end.cmp(&summary.min_start, buffer);
 873
 874        if inclusive {
 875            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 876        } else {
 877            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 878        }
 879    });
 880    cursor.next(buffer);
 881    cursor
 882}
 883
 884fn consolidate_inlay_edits(edits: &mut Vec<InlayEdit>) {
 885    edits.sort_unstable_by(|a, b| {
 886        a.old
 887            .start
 888            .cmp(&b.old.start)
 889            .then_with(|| b.old.end.cmp(&a.old.end))
 890    });
 891
 892    let mut i = 1;
 893    while i < edits.len() {
 894        let edit = edits[i].clone();
 895        let prev_edit = &mut edits[i - 1];
 896        if prev_edit.old.end >= edit.old.start {
 897            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 898            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 899            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 900            edits.remove(i);
 901            continue;
 902        }
 903        i += 1;
 904    }
 905}
 906
 907fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 908    edits.sort_unstable_by(|a, b| {
 909        a.old
 910            .start
 911            .cmp(&b.old.start)
 912            .then_with(|| b.old.end.cmp(&a.old.end))
 913    });
 914
 915    let mut i = 1;
 916    while i < edits.len() {
 917        let edit = edits[i].clone();
 918        let prev_edit = &mut edits[i - 1];
 919        if prev_edit.old.end >= edit.old.start {
 920            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 921            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 922            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 923            edits.remove(i);
 924            continue;
 925        }
 926        i += 1;
 927    }
 928}
 929
 930#[derive(Clone, Debug, Default, Eq, PartialEq)]
 931struct Transform {
 932    summary: TransformSummary,
 933    output_text: Option<&'static str>,
 934}
 935
 936impl Transform {
 937    fn is_fold(&self) -> bool {
 938        self.output_text.is_some()
 939    }
 940}
 941
 942#[derive(Clone, Debug, Default, Eq, PartialEq)]
 943struct TransformSummary {
 944    output: TextSummary,
 945    input: TextSummary,
 946}
 947
 948impl sum_tree::Item for Transform {
 949    type Summary = TransformSummary;
 950
 951    fn summary(&self) -> Self::Summary {
 952        self.summary.clone()
 953    }
 954}
 955
 956impl sum_tree::Summary for TransformSummary {
 957    type Context = ();
 958
 959    fn add_summary(&mut self, other: &Self, _: &()) {
 960        self.input += &other.input;
 961        self.output += &other.output;
 962    }
 963}
 964
 965#[derive(Clone, Debug)]
 966struct Fold(Range<Anchor>);
 967
 968impl Default for Fold {
 969    fn default() -> Self {
 970        Self(Anchor::min()..Anchor::max())
 971    }
 972}
 973
 974impl sum_tree::Item for Fold {
 975    type Summary = FoldSummary;
 976
 977    fn summary(&self) -> Self::Summary {
 978        FoldSummary {
 979            start: self.0.start.clone(),
 980            end: self.0.end.clone(),
 981            min_start: self.0.start.clone(),
 982            max_end: self.0.end.clone(),
 983            count: 1,
 984        }
 985    }
 986}
 987
 988#[derive(Clone, Debug)]
 989struct FoldSummary {
 990    start: Anchor,
 991    end: Anchor,
 992    min_start: Anchor,
 993    max_end: Anchor,
 994    count: usize,
 995}
 996
 997impl Default for FoldSummary {
 998    fn default() -> Self {
 999        Self {
1000            start: Anchor::min(),
1001            end: Anchor::max(),
1002            min_start: Anchor::max(),
1003            max_end: Anchor::min(),
1004            count: 0,
1005        }
1006    }
1007}
1008
1009impl sum_tree::Summary for FoldSummary {
1010    type Context = MultiBufferSnapshot;
1011
1012    fn add_summary(&mut self, other: &Self, buffer: &Self::Context) {
1013        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
1014            self.min_start = other.min_start.clone();
1015        }
1016        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
1017            self.max_end = other.max_end.clone();
1018        }
1019
1020        #[cfg(debug_assertions)]
1021        {
1022            let start_comparison = self.start.cmp(&other.start, buffer);
1023            assert!(start_comparison <= Ordering::Equal);
1024            if start_comparison == Ordering::Equal {
1025                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
1026            }
1027        }
1028
1029        self.start = other.start.clone();
1030        self.end = other.end.clone();
1031        self.count += other.count;
1032    }
1033}
1034
1035impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
1036    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1037        self.0.start = summary.start.clone();
1038        self.0.end = summary.end.clone();
1039    }
1040}
1041
1042impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
1043    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
1044        self.0.cmp(&other.0, buffer)
1045    }
1046}
1047
1048impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
1049    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1050        *self += summary.count;
1051    }
1052}
1053
1054#[derive(Clone)]
1055pub struct FoldBufferRows<'a> {
1056    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
1057    input_buffer_rows: MultiBufferRows<'a>,
1058    fold_point: FoldPoint,
1059}
1060
1061impl<'a> Iterator for FoldBufferRows<'a> {
1062    type Item = Option<u32>;
1063
1064    fn next(&mut self) -> Option<Self::Item> {
1065        let mut traversed_fold = false;
1066        while self.fold_point > self.cursor.end(&()).0 {
1067            self.cursor.next(&());
1068            traversed_fold = true;
1069            if self.cursor.item().is_none() {
1070                break;
1071            }
1072        }
1073
1074        if self.cursor.item().is_some() {
1075            if traversed_fold {
1076                self.input_buffer_rows.seek(self.cursor.start().1.row);
1077                self.input_buffer_rows.next();
1078            }
1079            *self.fold_point.row_mut() += 1;
1080            self.input_buffer_rows.next()
1081        } else {
1082            None
1083        }
1084    }
1085}
1086
1087pub struct FoldChunks<'a> {
1088    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1089    buffer_chunks: MultiBufferChunks<'a>,
1090    inlay_chunk: Option<(usize, Chunk<'a>)>,
1091    buffer_offset: usize,
1092    output_offset: usize,
1093    max_output_offset: usize,
1094    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1095    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1096    ellipses_color: Option<Color>,
1097}
1098
1099impl<'a> Iterator for FoldChunks<'a> {
1100    type Item = Chunk<'a>;
1101
1102    fn next(&mut self) -> Option<Self::Item> {
1103        if self.output_offset >= self.max_output_offset {
1104            return None;
1105        }
1106
1107        let transform = self.transform_cursor.item()?;
1108
1109        // If we're in a fold, then return the fold's display text and
1110        // advance the transform and buffer cursors to the end of the fold.
1111        if let Some(output_text) = transform.output_text {
1112            self.inlay_chunk.take();
1113            self.buffer_offset += transform.summary.input.len;
1114            self.buffer_chunks.seek(self.buffer_offset);
1115
1116            while self.buffer_offset >= self.transform_cursor.end(&()).1
1117                && self.transform_cursor.item().is_some()
1118            {
1119                self.transform_cursor.next(&());
1120            }
1121
1122            self.output_offset += output_text.len();
1123            return Some(Chunk {
1124                text: output_text,
1125                highlight_style: self.ellipses_color.map(|color| HighlightStyle {
1126                    color: Some(color),
1127                    ..Default::default()
1128                }),
1129                ..Default::default()
1130            });
1131        }
1132
1133        let mut next_highlight_endpoint = usize::MAX;
1134        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1135            if endpoint.offset <= self.buffer_offset {
1136                if endpoint.is_start {
1137                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1138                } else {
1139                    self.active_highlights.remove(&endpoint.tag);
1140                }
1141                self.highlight_endpoints.next();
1142            } else {
1143                next_highlight_endpoint = endpoint.offset;
1144                break;
1145            }
1146        }
1147
1148        // Retrieve a chunk from the current location in the buffer.
1149        if self.inlay_chunk.is_none() {
1150            let chunk_offset = self.buffer_chunks.offset();
1151            self.inlay_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1152        }
1153
1154        // Otherwise, take a chunk from the buffer's text.
1155        if let Some((buffer_chunk_start, mut chunk)) = self.inlay_chunk {
1156            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1157            let transform_end = self.transform_cursor.end(&()).1;
1158            let chunk_end = buffer_chunk_end
1159                .min(transform_end)
1160                .min(next_highlight_endpoint);
1161
1162            chunk.text = &chunk.text
1163                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1164
1165            if !self.active_highlights.is_empty() {
1166                let mut highlight_style = HighlightStyle::default();
1167                for active_highlight in self.active_highlights.values() {
1168                    highlight_style.highlight(*active_highlight);
1169                }
1170                chunk.highlight_style = Some(highlight_style);
1171            }
1172
1173            if chunk_end == transform_end {
1174                self.transform_cursor.next(&());
1175            } else if chunk_end == buffer_chunk_end {
1176                self.inlay_chunk.take();
1177            }
1178
1179            self.buffer_offset = chunk_end;
1180            self.output_offset += chunk.text.len();
1181            return Some(chunk);
1182        }
1183
1184        None
1185    }
1186}
1187
1188#[derive(Copy, Clone, Eq, PartialEq)]
1189struct HighlightEndpoint {
1190    offset: usize,
1191    is_start: bool,
1192    tag: Option<TypeId>,
1193    style: HighlightStyle,
1194}
1195
1196impl PartialOrd for HighlightEndpoint {
1197    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1198        Some(self.cmp(other))
1199    }
1200}
1201
1202impl Ord for HighlightEndpoint {
1203    fn cmp(&self, other: &Self) -> Ordering {
1204        self.offset
1205            .cmp(&other.offset)
1206            .then_with(|| other.is_start.cmp(&self.is_start))
1207    }
1208}
1209
1210#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1211pub struct FoldOffset(pub usize);
1212
1213impl FoldOffset {
1214    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1215        let mut cursor = snapshot
1216            .transforms
1217            .cursor::<(FoldOffset, TransformSummary)>();
1218        cursor.seek(&self, Bias::Right, &());
1219        // TODO kb seems wrong to use buffer points?
1220        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1221            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1222        } else {
1223            let buffer_offset = cursor.start().1.input.len + self.0 - cursor.start().0 .0;
1224            let buffer_point = snapshot
1225                .inlay_snapshot
1226                .buffer
1227                .offset_to_point(buffer_offset);
1228            buffer_point - cursor.start().1.input.lines
1229        };
1230        FoldPoint(cursor.start().1.output.lines + overshoot)
1231    }
1232}
1233
1234impl Add for FoldOffset {
1235    type Output = Self;
1236
1237    fn add(self, rhs: Self) -> Self::Output {
1238        Self(self.0 + rhs.0)
1239    }
1240}
1241
1242impl AddAssign for FoldOffset {
1243    fn add_assign(&mut self, rhs: Self) {
1244        self.0 += rhs.0;
1245    }
1246}
1247
1248impl Sub for FoldOffset {
1249    type Output = Self;
1250
1251    fn sub(self, rhs: Self) -> Self::Output {
1252        Self(self.0 - rhs.0)
1253    }
1254}
1255
1256impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1257    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1258        self.0 += &summary.output.len;
1259    }
1260}
1261
1262impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayPoint {
1263    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1264        self.0 += &summary.input.lines;
1265    }
1266}
1267
1268impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayOffset {
1269    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1270        self.0 += &summary.input.len;
1271    }
1272}
1273
1274impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1275    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1276        *self += &summary.input.lines;
1277    }
1278}
1279
1280impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1281    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1282        *self += &summary.input.len;
1283    }
1284}
1285
1286pub type FoldEdit = Edit<FoldOffset>;
1287
1288#[cfg(test)]
1289mod tests {
1290    use super::*;
1291    use crate::{display_map::inlay_map::InlayMap, MultiBuffer, ToPoint};
1292    use collections::HashSet;
1293    use rand::prelude::*;
1294    use settings::SettingsStore;
1295    use std::{cmp::Reverse, env, mem, sync::Arc};
1296    use sum_tree::TreeMap;
1297    use util::test::sample_text;
1298    use util::RandomCharIter;
1299    use Bias::{Left, Right};
1300
1301    #[gpui::test]
1302    fn test_basic_folds(cx: &mut gpui::AppContext) {
1303        init_test(cx);
1304        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1305        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1306        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1307        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1308        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1309
1310        let (mut writer, _, _) = map.write(inlay_snapshot, vec![]);
1311        let (snapshot2, edits) = writer.fold(vec![
1312            Point::new(0, 2)..Point::new(2, 2),
1313            Point::new(2, 4)..Point::new(4, 1),
1314        ]);
1315        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1316        assert_eq!(
1317            edits,
1318            &[
1319                FoldEdit {
1320                    old: FoldOffset(2)..FoldOffset(16),
1321                    new: FoldOffset(2)..FoldOffset(5),
1322                },
1323                FoldEdit {
1324                    old: FoldOffset(18)..FoldOffset(29),
1325                    new: FoldOffset(7)..FoldOffset(10)
1326                },
1327            ]
1328        );
1329
1330        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1331            buffer.edit(
1332                vec![
1333                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1334                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1335                ],
1336                None,
1337                cx,
1338            );
1339            buffer.snapshot(cx)
1340        });
1341
1342        let (inlay_snapshot, inlay_edits) =
1343            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1344        let (snapshot3, edits) = map.read(inlay_snapshot, inlay_edits);
1345        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1346        assert_eq!(
1347            edits,
1348            &[
1349                FoldEdit {
1350                    old: FoldOffset(0)..FoldOffset(1),
1351                    new: FoldOffset(0)..FoldOffset(3),
1352                },
1353                FoldEdit {
1354                    old: FoldOffset(6)..FoldOffset(6),
1355                    new: FoldOffset(8)..FoldOffset(11),
1356                },
1357            ]
1358        );
1359
1360        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1361            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1362            buffer.snapshot(cx)
1363        });
1364        let (inlay_snapshot, inlay_edits) =
1365            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1366        let (snapshot4, _) = map.read(inlay_snapshot.clone(), inlay_edits);
1367        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1368
1369        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1370        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1371        let (snapshot5, _) = map.read(inlay_snapshot.clone(), vec![]);
1372        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1373
1374        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1375        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1376        let (snapshot6, _) = map.read(inlay_snapshot, vec![]);
1377        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1378    }
1379
1380    #[gpui::test]
1381    fn test_adjacent_folds(cx: &mut gpui::AppContext) {
1382        init_test(cx);
1383        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1384        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1385        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1386        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1387
1388        {
1389            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1390
1391            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1392            writer.fold(vec![5..8]);
1393            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1394            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1395
1396            // Create an fold adjacent to the start of the first fold.
1397            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1398            writer.fold(vec![0..1, 2..5]);
1399            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1400            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1401
1402            // Create an fold adjacent to the end of the first fold.
1403            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1404            writer.fold(vec![11..11, 8..10]);
1405            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1406            assert_eq!(snapshot.text(), "⋯b⋯kl");
1407        }
1408
1409        {
1410            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1411
1412            // Create two adjacent folds.
1413            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1414            writer.fold(vec![0..2, 2..5]);
1415            let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1416            assert_eq!(snapshot.text(), "⋯fghijkl");
1417
1418            // Edit within one of the folds.
1419            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1420                buffer.edit([(0..1, "12345")], None, cx);
1421                buffer.snapshot(cx)
1422            });
1423            let (inlay_snapshot, inlay_edits) =
1424                inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1425            let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1426            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1427        }
1428    }
1429
1430    #[gpui::test]
1431    fn test_overlapping_folds(cx: &mut gpui::AppContext) {
1432        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1433        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1434        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1435        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1436        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1437        writer.fold(vec![
1438            Point::new(0, 2)..Point::new(2, 2),
1439            Point::new(0, 4)..Point::new(1, 0),
1440            Point::new(1, 2)..Point::new(3, 2),
1441            Point::new(3, 1)..Point::new(4, 1),
1442        ]);
1443        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1444        assert_eq!(snapshot.text(), "aa⋯eeeee");
1445    }
1446
1447    #[gpui::test]
1448    fn test_merging_folds_via_edit(cx: &mut gpui::AppContext) {
1449        init_test(cx);
1450        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1451        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1452        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1453        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1454        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1455
1456        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1457        writer.fold(vec![
1458            Point::new(0, 2)..Point::new(2, 2),
1459            Point::new(3, 1)..Point::new(4, 1),
1460        ]);
1461        let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1462        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1463
1464        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1465            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1466            buffer.snapshot(cx)
1467        });
1468        let (inlay_snapshot, inlay_edits) =
1469            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1470        let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1471        assert_eq!(snapshot.text(), "aa⋯eeeee");
1472    }
1473
1474    #[gpui::test]
1475    fn test_folds_in_range(cx: &mut gpui::AppContext) {
1476        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1477        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1478        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1479        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1480
1481        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1482        writer.fold(vec![
1483            Point::new(0, 2)..Point::new(2, 2),
1484            Point::new(0, 4)..Point::new(1, 0),
1485            Point::new(1, 2)..Point::new(3, 2),
1486            Point::new(3, 1)..Point::new(4, 1),
1487        ]);
1488        let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1489        let fold_ranges = snapshot
1490            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1491            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1492            .collect::<Vec<_>>();
1493        assert_eq!(
1494            fold_ranges,
1495            vec![
1496                Point::new(0, 2)..Point::new(2, 2),
1497                Point::new(1, 2)..Point::new(3, 2)
1498            ]
1499        );
1500    }
1501
1502    #[gpui::test(iterations = 100)]
1503    fn test_random_folds(cx: &mut gpui::AppContext, mut rng: StdRng) {
1504        init_test(cx);
1505        let operations = env::var("OPERATIONS")
1506            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1507            .unwrap_or(10);
1508
1509        let len = rng.gen_range(0..10);
1510        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1511        let buffer = if rng.gen() {
1512            MultiBuffer::build_simple(&text, cx)
1513        } else {
1514            MultiBuffer::build_random(&mut rng, cx)
1515        };
1516        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1517        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1518        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1519
1520        let (mut initial_snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1521        let mut snapshot_edits = Vec::new();
1522
1523        let mut highlights = TreeMap::default();
1524        let highlight_count = rng.gen_range(0_usize..10);
1525        let mut highlight_ranges = (0..highlight_count)
1526            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1527            .collect::<Vec<_>>();
1528        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1529        log::info!("highlighting ranges {:?}", highlight_ranges);
1530        let highlight_ranges = highlight_ranges
1531            .into_iter()
1532            .map(|range| {
1533                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1534            })
1535            .collect::<Vec<_>>();
1536
1537        highlights.insert(
1538            Some(TypeId::of::<()>()),
1539            Arc::new((HighlightStyle::default(), highlight_ranges)),
1540        );
1541
1542        for _ in 0..operations {
1543            log::info!("text: {:?}", buffer_snapshot.text());
1544            let mut buffer_edits = Vec::new();
1545            match rng.gen_range(0..=100) {
1546                0..=59 => {
1547                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1548                }
1549                _ => buffer.update(cx, |buffer, cx| {
1550                    let subscription = buffer.subscribe();
1551                    let edit_count = rng.gen_range(1..=5);
1552                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1553                    buffer_snapshot = buffer.snapshot(cx);
1554                    let edits = subscription.consume().into_inner();
1555                    log::info!("editing {:?}", edits);
1556                    buffer_edits.extend(edits);
1557                }),
1558            };
1559
1560            let (inlay_snapshot, inlay_edits) =
1561                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
1562            let (snapshot, edits) = map.read(inlay_snapshot.clone(), inlay_edits);
1563            snapshot_edits.push((snapshot.clone(), edits));
1564
1565            let mut expected_text: String = buffer_snapshot.text().to_string();
1566            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1567                expected_text.replace_range(fold_range.start..fold_range.end, "");
1568            }
1569
1570            assert_eq!(snapshot.text(), expected_text);
1571            log::info!(
1572                "fold text {:?} ({} lines)",
1573                expected_text,
1574                expected_text.matches('\n').count() + 1
1575            );
1576
1577            let mut prev_row = 0;
1578            let mut expected_buffer_rows = Vec::new();
1579            for fold_range in map.merged_fold_ranges().into_iter() {
1580                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1581                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1582                expected_buffer_rows.extend(
1583                    buffer_snapshot
1584                        .buffer_rows(prev_row)
1585                        .take((1 + fold_start - prev_row) as usize),
1586                );
1587                prev_row = 1 + fold_end;
1588            }
1589            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1590
1591            assert_eq!(
1592                expected_buffer_rows.len(),
1593                expected_text.matches('\n').count() + 1,
1594                "wrong expected buffer rows {:?}. text: {:?}",
1595                expected_buffer_rows,
1596                expected_text
1597            );
1598
1599            for (output_row, line) in expected_text.lines().enumerate() {
1600                let line_len = snapshot.line_len(output_row as u32);
1601                assert_eq!(line_len, line.len() as u32);
1602            }
1603
1604            let longest_row = snapshot.longest_row();
1605            let longest_char_column = expected_text
1606                .split('\n')
1607                .nth(longest_row as usize)
1608                .unwrap()
1609                .chars()
1610                .count();
1611            let mut fold_point = FoldPoint::new(0, 0);
1612            let mut fold_offset = FoldOffset(0);
1613            let mut char_column = 0;
1614            for c in expected_text.chars() {
1615                let inlay_point = fold_point.to_inlay_point(&snapshot);
1616                let buffer_point = inlay_snapshot.to_buffer_point(inlay_point);
1617                let buffer_offset = buffer_snapshot.point_to_offset(buffer_point);
1618                assert_eq!(
1619                    snapshot.to_fold_point(inlay_point, Right),
1620                    fold_point,
1621                    "{:?} -> fold point",
1622                    buffer_point,
1623                );
1624                assert_eq!(
1625                    inlay_snapshot.to_buffer_offset(inlay_snapshot.to_offset(inlay_point)),
1626                    buffer_offset,
1627                    "inlay_snapshot.to_buffer_offset(inlay_snapshot.to_offset(({:?}))",
1628                    inlay_point,
1629                );
1630                assert_eq!(
1631                    fold_point.to_offset(&snapshot),
1632                    fold_offset,
1633                    "fold_point.to_offset({:?})",
1634                    fold_point,
1635                );
1636
1637                if c == '\n' {
1638                    *fold_point.row_mut() += 1;
1639                    *fold_point.column_mut() = 0;
1640                    char_column = 0;
1641                } else {
1642                    *fold_point.column_mut() += c.len_utf8() as u32;
1643                    char_column += 1;
1644                }
1645                fold_offset.0 += c.len_utf8();
1646                if char_column > longest_char_column {
1647                    panic!(
1648                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1649                        longest_row,
1650                        longest_char_column,
1651                        fold_point.row(),
1652                        char_column
1653                    );
1654                }
1655            }
1656
1657            for _ in 0..5 {
1658                let mut start = snapshot
1659                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1660                let mut end = snapshot
1661                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1662                if start > end {
1663                    mem::swap(&mut start, &mut end);
1664                }
1665
1666                let text = &expected_text[start.0..end.0];
1667                assert_eq!(
1668                    snapshot
1669                        .chunks(start..end, false, Some(&highlights), None)
1670                        .map(|c| c.text)
1671                        .collect::<String>(),
1672                    text,
1673                );
1674            }
1675
1676            let mut fold_row = 0;
1677            while fold_row < expected_buffer_rows.len() as u32 {
1678                fold_row = snapshot
1679                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1680                    .row();
1681                assert_eq!(
1682                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1683                    expected_buffer_rows[(fold_row as usize)..],
1684                    "wrong buffer rows starting at fold row {}",
1685                    fold_row,
1686                );
1687                fold_row += 1;
1688            }
1689
1690            let fold_start_rows = map
1691                .merged_fold_ranges()
1692                .iter()
1693                .map(|range| range.start.to_point(&buffer_snapshot).row)
1694                .collect::<HashSet<_>>();
1695            for row in fold_start_rows {
1696                assert!(snapshot.is_line_folded(row));
1697            }
1698
1699            for _ in 0..5 {
1700                let end =
1701                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1702                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1703                let expected_folds = map
1704                    .folds
1705                    .items(&buffer_snapshot)
1706                    .into_iter()
1707                    .filter(|fold| {
1708                        let start = buffer_snapshot.anchor_before(start);
1709                        let end = buffer_snapshot.anchor_after(end);
1710                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1711                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1712                    })
1713                    .map(|fold| fold.0)
1714                    .collect::<Vec<_>>();
1715
1716                assert_eq!(
1717                    snapshot
1718                        .folds_in_range(start..end)
1719                        .cloned()
1720                        .collect::<Vec<_>>(),
1721                    expected_folds
1722                );
1723            }
1724
1725            let text = snapshot.text();
1726            for _ in 0..5 {
1727                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1728                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1729                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1730                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1731                let mut start =
1732                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1733                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1734                if start > end {
1735                    mem::swap(&mut start, &mut end);
1736                }
1737
1738                let lines = start..end;
1739                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1740                assert_eq!(
1741                    snapshot.text_summary_for_range(lines),
1742                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1743                )
1744            }
1745
1746            let mut text = initial_snapshot.text();
1747            for (snapshot, edits) in snapshot_edits.drain(..) {
1748                let new_text = snapshot.text();
1749                for edit in edits {
1750                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1751                    let new_bytes = edit.new.start.0..edit.new.end.0;
1752                    text.replace_range(old_bytes, &new_text[new_bytes]);
1753                }
1754
1755                assert_eq!(text, new_text);
1756                initial_snapshot = snapshot;
1757            }
1758        }
1759    }
1760
1761    #[gpui::test]
1762    fn test_buffer_rows(cx: &mut gpui::AppContext) {
1763        let text = sample_text(6, 6, 'a') + "\n";
1764        let buffer = MultiBuffer::build_simple(&text, cx);
1765
1766        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1767        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1768        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1769
1770        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1771        writer.fold(vec![
1772            Point::new(0, 2)..Point::new(2, 2),
1773            Point::new(3, 1)..Point::new(4, 1),
1774        ]);
1775
1776        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1777        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
1778        assert_eq!(
1779            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1780            [Some(0), Some(3), Some(5), Some(6)]
1781        );
1782        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1783    }
1784
1785    fn init_test(cx: &mut gpui::AppContext) {
1786        cx.set_global(SettingsStore::test(cx));
1787    }
1788
1789    impl FoldMap {
1790        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1791            let inlay_snapshot = self.inlay_snapshot.lock().clone();
1792            let buffer = &inlay_snapshot.buffer;
1793            let mut folds = self.folds.items(buffer);
1794            // Ensure sorting doesn't change how folds get merged and displayed.
1795            folds.sort_by(|a, b| a.0.cmp(&b.0, buffer));
1796            let mut fold_ranges = folds
1797                .iter()
1798                .map(|fold| fold.0.start.to_offset(buffer)..fold.0.end.to_offset(buffer))
1799                .peekable();
1800
1801            let mut merged_ranges = Vec::new();
1802            while let Some(mut fold_range) = fold_ranges.next() {
1803                while let Some(next_range) = fold_ranges.peek() {
1804                    if fold_range.end >= next_range.start {
1805                        if next_range.end > fold_range.end {
1806                            fold_range.end = next_range.end;
1807                        }
1808                        fold_ranges.next();
1809                    } else {
1810                        break;
1811                    }
1812                }
1813                if fold_range.end > fold_range.start {
1814                    merged_ranges.push(fold_range);
1815                }
1816            }
1817            merged_ranges
1818        }
1819
1820        pub fn randomly_mutate(
1821            &mut self,
1822            rng: &mut impl Rng,
1823        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1824            let mut snapshot_edits = Vec::new();
1825            match rng.gen_range(0..=100) {
1826                0..=39 if !self.folds.is_empty() => {
1827                    let inlay_snapshot = self.inlay_snapshot.lock().clone();
1828                    let buffer = &inlay_snapshot.buffer;
1829                    let mut to_unfold = Vec::new();
1830                    for _ in 0..rng.gen_range(1..=3) {
1831                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1832                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1833                        to_unfold.push(start..end);
1834                    }
1835                    log::info!("unfolding {:?}", to_unfold);
1836                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
1837                    snapshot_edits.push((snapshot, edits));
1838                    let (snapshot, edits) = writer.fold(to_unfold);
1839                    snapshot_edits.push((snapshot, edits));
1840                }
1841                _ => {
1842                    let inlay_snapshot = self.inlay_snapshot.lock().clone();
1843                    let buffer = &inlay_snapshot.buffer;
1844                    let mut to_fold = Vec::new();
1845                    for _ in 0..rng.gen_range(1..=2) {
1846                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1847                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1848                        to_fold.push(start..end);
1849                    }
1850                    log::info!("folding {:?}", to_fold);
1851                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
1852                    snapshot_edits.push((snapshot, edits));
1853                    let (snapshot, edits) = writer.fold(to_fold);
1854                    snapshot_edits.push((snapshot, edits));
1855                }
1856            }
1857            snapshot_edits
1858        }
1859    }
1860}