1use crate::{
   2    multi_buffer::MultiBufferRows, Anchor, AnchorRangeExt, MultiBufferChunks, MultiBufferSnapshot,
   3    ToOffset,
   4};
   5use language::{Chunk, Edit, Point, PointUtf16, TextSummary};
   6use parking_lot::Mutex;
   7use std::{
   8    cmp::{self, Ordering},
   9    iter,
  10    ops::{Range, Sub},
  11    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  12};
  13use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  14
  15pub trait ToFoldPoint {
  16    fn to_fold_point(&self, snapshot: &FoldSnapshot, bias: Bias) -> FoldPoint;
  17}
  18
  19#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  20pub struct FoldPoint(pub super::Point);
  21
  22impl FoldPoint {
  23    pub fn new(row: u32, column: u32) -> Self {
  24        Self(super::Point::new(row, column))
  25    }
  26
  27    pub fn row(self) -> u32 {
  28        self.0.row
  29    }
  30
  31    pub fn column(self) -> u32 {
  32        self.0.column
  33    }
  34
  35    pub fn row_mut(&mut self) -> &mut u32 {
  36        &mut self.0.row
  37    }
  38
  39    pub fn column_mut(&mut self) -> &mut u32 {
  40        &mut self.0.column
  41    }
  42
  43    pub fn to_buffer_point(&self, snapshot: &FoldSnapshot) -> Point {
  44        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  45        cursor.seek(self, Bias::Right, &());
  46        let overshoot = self.0 - cursor.start().0 .0;
  47        cursor.start().1 + overshoot
  48    }
  49
  50    pub fn to_buffer_offset(&self, snapshot: &FoldSnapshot) -> usize {
  51        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  52        cursor.seek(self, Bias::Right, &());
  53        let overshoot = self.0 - cursor.start().0 .0;
  54        snapshot
  55            .buffer_snapshot
  56            .point_to_offset(cursor.start().1 + overshoot)
  57    }
  58
  59    pub fn to_offset(&self, snapshot: &FoldSnapshot) -> FoldOffset {
  60        let mut cursor = snapshot
  61            .transforms
  62            .cursor::<(FoldPoint, TransformSummary)>();
  63        cursor.seek(self, Bias::Right, &());
  64        let overshoot = self.0 - cursor.start().1.output.lines;
  65        let mut offset = cursor.start().1.output.bytes;
  66        if !overshoot.is_zero() {
  67            let transform = cursor.item().expect("display point out of range");
  68            assert!(transform.output_text.is_none());
  69            let end_buffer_offset = snapshot
  70                .buffer_snapshot
  71                .point_to_offset(cursor.start().1.input.lines + overshoot);
  72            offset += end_buffer_offset - cursor.start().1.input.bytes;
  73        }
  74        FoldOffset(offset)
  75    }
  76}
  77
  78impl ToFoldPoint for Point {
  79    fn to_fold_point(&self, snapshot: &FoldSnapshot, bias: Bias) -> FoldPoint {
  80        let mut cursor = snapshot.transforms.cursor::<(Point, FoldPoint)>();
  81        cursor.seek(self, Bias::Right, &());
  82        if cursor.item().map_or(false, |t| t.is_fold()) {
  83            if bias == Bias::Left || *self == cursor.start().0 {
  84                cursor.start().1
  85            } else {
  86                cursor.end(&()).1
  87            }
  88        } else {
  89            let overshoot = *self - cursor.start().0;
  90            FoldPoint(cmp::min(
  91                cursor.start().1 .0 + overshoot,
  92                cursor.end(&()).1 .0,
  93            ))
  94        }
  95    }
  96}
  97
  98pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  99
 100impl<'a> FoldMapWriter<'a> {
 101    pub fn fold<T: ToOffset>(
 102        &mut self,
 103        ranges: impl IntoIterator<Item = Range<T>>,
 104    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 105        let mut edits = Vec::new();
 106        let mut folds = Vec::new();
 107        let buffer = self.0.buffer.lock().clone();
 108        for range in ranges.into_iter() {
 109            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 110
 111            // Ignore any empty ranges.
 112            if range.start == range.end {
 113                continue;
 114            }
 115
 116            // For now, ignore any ranges that span an excerpt boundary.
 117            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 118            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 119                continue;
 120            }
 121
 122            folds.push(fold);
 123            edits.push(text::Edit {
 124                old: range.clone(),
 125                new: range,
 126            });
 127        }
 128
 129        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 130
 131        self.0.folds = {
 132            let mut new_tree = SumTree::new();
 133            let mut cursor = self.0.folds.cursor::<Fold>();
 134            for fold in folds {
 135                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 136                new_tree.push(fold, &buffer);
 137            }
 138            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 139            new_tree
 140        };
 141
 142        consolidate_buffer_edits(&mut edits);
 143        let edits = self.0.sync(buffer.clone(), edits);
 144        let snapshot = FoldSnapshot {
 145            transforms: self.0.transforms.lock().clone(),
 146            folds: self.0.folds.clone(),
 147            buffer_snapshot: buffer,
 148            version: self.0.version.load(SeqCst),
 149        };
 150        (snapshot, edits)
 151    }
 152
 153    pub fn unfold<T: ToOffset>(
 154        &mut self,
 155        ranges: impl IntoIterator<Item = Range<T>>,
 156    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 157        let mut edits = Vec::new();
 158        let mut fold_ixs_to_delete = Vec::new();
 159        let buffer = self.0.buffer.lock().clone();
 160        for range in ranges.into_iter() {
 161            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 162            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 163            while let Some(fold) = folds_cursor.item() {
 164                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 165                if offset_range.end > offset_range.start {
 166                    edits.push(text::Edit {
 167                        old: offset_range.clone(),
 168                        new: offset_range,
 169                    });
 170                }
 171                fold_ixs_to_delete.push(*folds_cursor.start());
 172                folds_cursor.next(&buffer);
 173            }
 174        }
 175
 176        fold_ixs_to_delete.sort_unstable();
 177        fold_ixs_to_delete.dedup();
 178
 179        self.0.folds = {
 180            let mut cursor = self.0.folds.cursor::<usize>();
 181            let mut folds = SumTree::new();
 182            for fold_ix in fold_ixs_to_delete {
 183                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 184                cursor.next(&buffer);
 185            }
 186            folds.push_tree(cursor.suffix(&buffer), &buffer);
 187            folds
 188        };
 189
 190        consolidate_buffer_edits(&mut edits);
 191        let edits = self.0.sync(buffer.clone(), edits);
 192        let snapshot = FoldSnapshot {
 193            transforms: self.0.transforms.lock().clone(),
 194            folds: self.0.folds.clone(),
 195            buffer_snapshot: buffer,
 196            version: self.0.version.load(SeqCst),
 197        };
 198        (snapshot, edits)
 199    }
 200}
 201
 202pub struct FoldMap {
 203    buffer: Mutex<MultiBufferSnapshot>,
 204    transforms: Mutex<SumTree<Transform>>,
 205    folds: SumTree<Fold>,
 206    version: AtomicUsize,
 207}
 208
 209impl FoldMap {
 210    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 211        let this = Self {
 212            buffer: Mutex::new(buffer.clone()),
 213            folds: Default::default(),
 214            transforms: Mutex::new(SumTree::from_item(
 215                Transform {
 216                    summary: TransformSummary {
 217                        input: buffer.text_summary(),
 218                        output: buffer.text_summary(),
 219                    },
 220                    output_text: None,
 221                },
 222                &(),
 223            )),
 224            version: Default::default(),
 225        };
 226
 227        let snapshot = FoldSnapshot {
 228            transforms: this.transforms.lock().clone(),
 229            folds: this.folds.clone(),
 230            buffer_snapshot: this.buffer.lock().clone(),
 231            version: this.version.load(SeqCst),
 232        };
 233        (this, snapshot)
 234    }
 235
 236    pub fn read(
 237        &self,
 238        buffer: MultiBufferSnapshot,
 239        edits: Vec<Edit<usize>>,
 240    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 241        let edits = self.sync(buffer, edits);
 242        self.check_invariants();
 243        let snapshot = FoldSnapshot {
 244            transforms: self.transforms.lock().clone(),
 245            folds: self.folds.clone(),
 246            buffer_snapshot: self.buffer.lock().clone(),
 247            version: self.version.load(SeqCst),
 248        };
 249        (snapshot, edits)
 250    }
 251
 252    pub fn write(
 253        &mut self,
 254        buffer: MultiBufferSnapshot,
 255        edits: Vec<Edit<usize>>,
 256    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 257        let (snapshot, edits) = self.read(buffer, edits);
 258        (FoldMapWriter(self), snapshot, edits)
 259    }
 260
 261    fn check_invariants(&self) {
 262        if cfg!(test) {
 263            assert_eq!(
 264                self.transforms.lock().summary().input.bytes,
 265                self.buffer.lock().len(),
 266                "transform tree does not match buffer's length"
 267            );
 268        }
 269    }
 270
 271    fn sync(
 272        &self,
 273        new_buffer: MultiBufferSnapshot,
 274        buffer_edits: Vec<text::Edit<usize>>,
 275    ) -> Vec<FoldEdit> {
 276        if buffer_edits.is_empty() {
 277            let mut buffer = self.buffer.lock();
 278            if buffer.parse_count() != new_buffer.parse_count()
 279                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 280                || buffer.trailing_excerpt_update_count()
 281                    != new_buffer.trailing_excerpt_update_count()
 282            {
 283                self.version.fetch_add(1, SeqCst);
 284            }
 285            *buffer = new_buffer;
 286            Vec::new()
 287        } else {
 288            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 289
 290            let mut new_transforms = SumTree::new();
 291            let mut transforms = self.transforms.lock();
 292            let mut cursor = transforms.cursor::<usize>();
 293            cursor.seek(&0, Bias::Right, &());
 294
 295            while let Some(mut edit) = buffer_edits_iter.next() {
 296                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 297                edit.new.start -= edit.old.start - cursor.start();
 298                edit.old.start = *cursor.start();
 299
 300                cursor.seek(&edit.old.end, Bias::Right, &());
 301                cursor.next(&());
 302
 303                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 304                loop {
 305                    edit.old.end = *cursor.start();
 306
 307                    if let Some(next_edit) = buffer_edits_iter.peek() {
 308                        if next_edit.old.start > edit.old.end {
 309                            break;
 310                        }
 311
 312                        let next_edit = buffer_edits_iter.next().unwrap();
 313                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 314
 315                        if next_edit.old.end >= edit.old.end {
 316                            edit.old.end = next_edit.old.end;
 317                            cursor.seek(&edit.old.end, Bias::Right, &());
 318                            cursor.next(&());
 319                        }
 320                    } else {
 321                        break;
 322                    }
 323                }
 324
 325                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 326
 327                let anchor = new_buffer.anchor_before(edit.new.start);
 328                let mut folds_cursor = self.folds.cursor::<Fold>();
 329                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 330
 331                let mut folds = iter::from_fn({
 332                    let buffer = &new_buffer;
 333                    move || {
 334                        let item = folds_cursor
 335                            .item()
 336                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 337                        folds_cursor.next(buffer);
 338                        item
 339                    }
 340                })
 341                .peekable();
 342
 343                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 344                    let mut fold = folds.next().unwrap();
 345                    let sum = new_transforms.summary();
 346
 347                    assert!(fold.start >= sum.input.bytes);
 348
 349                    while folds
 350                        .peek()
 351                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 352                    {
 353                        let next_fold = folds.next().unwrap();
 354                        if next_fold.end > fold.end {
 355                            fold.end = next_fold.end;
 356                        }
 357                    }
 358
 359                    if fold.start > sum.input.bytes {
 360                        let text_summary = new_buffer
 361                            .text_summary_for_range::<TextSummary, _>(sum.input.bytes..fold.start);
 362                        new_transforms.push(
 363                            Transform {
 364                                summary: TransformSummary {
 365                                    output: text_summary.clone(),
 366                                    input: text_summary,
 367                                },
 368                                output_text: None,
 369                            },
 370                            &(),
 371                        );
 372                    }
 373
 374                    if fold.end > fold.start {
 375                        let output_text = "…";
 376                        let chars = output_text.chars().count() as u32;
 377                        let lines = Point::new(0, output_text.len() as u32);
 378                        let lines_utf16 =
 379                            PointUtf16::new(0, output_text.encode_utf16().count() as u32);
 380                        new_transforms.push(
 381                            Transform {
 382                                summary: TransformSummary {
 383                                    output: TextSummary {
 384                                        bytes: output_text.len(),
 385                                        lines,
 386                                        lines_utf16,
 387                                        first_line_chars: chars,
 388                                        last_line_chars: chars,
 389                                        longest_row: 0,
 390                                        longest_row_chars: chars,
 391                                    },
 392                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 393                                },
 394                                output_text: Some(output_text),
 395                            },
 396                            &(),
 397                        );
 398                    }
 399                }
 400
 401                let sum = new_transforms.summary();
 402                if sum.input.bytes < edit.new.end {
 403                    let text_summary = new_buffer
 404                        .text_summary_for_range::<TextSummary, _>(sum.input.bytes..edit.new.end);
 405                    new_transforms.push(
 406                        Transform {
 407                            summary: TransformSummary {
 408                                output: text_summary.clone(),
 409                                input: text_summary,
 410                            },
 411                            output_text: None,
 412                        },
 413                        &(),
 414                    );
 415                }
 416            }
 417
 418            new_transforms.push_tree(cursor.suffix(&()), &());
 419            if new_transforms.is_empty() {
 420                let text_summary = new_buffer.text_summary();
 421                new_transforms.push(
 422                    Transform {
 423                        summary: TransformSummary {
 424                            output: text_summary.clone(),
 425                            input: text_summary,
 426                        },
 427                        output_text: None,
 428                    },
 429                    &(),
 430                );
 431            }
 432
 433            drop(cursor);
 434
 435            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 436            {
 437                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 438                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 439
 440                for mut edit in buffer_edits {
 441                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 442                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 443                        edit.old.start = old_transforms.start().0;
 444                    }
 445                    let old_start =
 446                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 447
 448                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 449                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 450                        old_transforms.next(&());
 451                        edit.old.end = old_transforms.start().0;
 452                    }
 453                    let old_end =
 454                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 455
 456                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 457                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 458                        edit.new.start = new_transforms.start().0;
 459                    }
 460                    let new_start =
 461                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 462
 463                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 464                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 465                        new_transforms.next(&());
 466                        edit.new.end = new_transforms.start().0;
 467                    }
 468                    let new_end =
 469                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 470
 471                    fold_edits.push(FoldEdit {
 472                        old: FoldOffset(old_start)..FoldOffset(old_end),
 473                        new: FoldOffset(new_start)..FoldOffset(new_end),
 474                    });
 475                }
 476
 477                consolidate_fold_edits(&mut fold_edits);
 478            }
 479
 480            *transforms = new_transforms;
 481            *self.buffer.lock() = new_buffer;
 482            self.version.fetch_add(1, SeqCst);
 483            fold_edits
 484        }
 485    }
 486}
 487
 488#[derive(Clone)]
 489pub struct FoldSnapshot {
 490    transforms: SumTree<Transform>,
 491    folds: SumTree<Fold>,
 492    buffer_snapshot: MultiBufferSnapshot,
 493    pub version: usize,
 494}
 495
 496impl FoldSnapshot {
 497    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 498        &self.buffer_snapshot
 499    }
 500
 501    #[cfg(test)]
 502    pub fn text(&self) -> String {
 503        self.chunks(FoldOffset(0)..self.len(), false)
 504            .map(|c| c.text)
 505            .collect()
 506    }
 507
 508    #[cfg(test)]
 509    pub fn fold_count(&self) -> usize {
 510        self.folds.items(&self.buffer_snapshot).len()
 511    }
 512
 513    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 514        let mut summary = TextSummary::default();
 515
 516        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 517        cursor.seek(&range.start, Bias::Right, &());
 518        if let Some(transform) = cursor.item() {
 519            let start_in_transform = range.start.0 - cursor.start().0 .0;
 520            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 521            if let Some(output_text) = transform.output_text {
 522                summary = TextSummary::from(
 523                    &output_text
 524                        [start_in_transform.column as usize..end_in_transform.column as usize],
 525                );
 526            } else {
 527                let buffer_start = cursor.start().1 + start_in_transform;
 528                let buffer_end = cursor.start().1 + end_in_transform;
 529                summary = self
 530                    .buffer_snapshot
 531                    .text_summary_for_range(buffer_start..buffer_end);
 532            }
 533        }
 534
 535        if range.end > cursor.end(&()).0 {
 536            cursor.next(&());
 537            summary += &cursor
 538                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 539                .output;
 540            if let Some(transform) = cursor.item() {
 541                let end_in_transform = range.end.0 - cursor.start().0 .0;
 542                if let Some(output_text) = transform.output_text {
 543                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 544                } else {
 545                    let buffer_start = cursor.start().1;
 546                    let buffer_end = cursor.start().1 + end_in_transform;
 547                    summary += self
 548                        .buffer_snapshot
 549                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 550                }
 551            }
 552        }
 553
 554        summary
 555    }
 556
 557    pub fn len(&self) -> FoldOffset {
 558        FoldOffset(self.transforms.summary().output.bytes)
 559    }
 560
 561    pub fn line_len(&self, row: u32) -> u32 {
 562        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 563        let line_end = if row >= self.max_point().row() {
 564            self.len().0
 565        } else {
 566            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 567        };
 568        (line_end - line_start) as u32
 569    }
 570
 571    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 572        if start_row > self.transforms.summary().output.lines.row {
 573            panic!("invalid display row {}", start_row);
 574        }
 575
 576        let fold_point = FoldPoint::new(start_row, 0);
 577        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 578        cursor.seek(&fold_point, Bias::Left, &());
 579
 580        let overshoot = fold_point.0 - cursor.start().0 .0;
 581        let buffer_point = cursor.start().1 + overshoot;
 582        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 583
 584        FoldBufferRows {
 585            fold_point,
 586            input_buffer_rows,
 587            cursor,
 588        }
 589    }
 590
 591    pub fn max_point(&self) -> FoldPoint {
 592        FoldPoint(self.transforms.summary().output.lines)
 593    }
 594
 595    #[cfg(test)]
 596    pub fn longest_row(&self) -> u32 {
 597        self.transforms.summary().output.longest_row
 598    }
 599
 600    pub fn folds_in_range<'a, T>(
 601        &'a self,
 602        range: Range<T>,
 603    ) -> impl Iterator<Item = &'a Range<Anchor>>
 604    where
 605        T: ToOffset,
 606    {
 607        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 608        iter::from_fn(move || {
 609            let item = folds.item().map(|f| &f.0);
 610            folds.next(&self.buffer_snapshot);
 611            item
 612        })
 613    }
 614
 615    pub fn intersects_fold<T>(&self, offset: T) -> bool
 616    where
 617        T: ToOffset,
 618    {
 619        let offset = offset.to_offset(&self.buffer_snapshot);
 620        let mut cursor = self.transforms.cursor::<usize>();
 621        cursor.seek(&offset, Bias::Right, &());
 622        cursor.item().map_or(false, |t| t.output_text.is_some())
 623    }
 624
 625    pub fn is_line_folded(&self, output_row: u32) -> bool {
 626        let mut cursor = self.transforms.cursor::<FoldPoint>();
 627        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 628        while let Some(transform) = cursor.item() {
 629            if transform.output_text.is_some() {
 630                return true;
 631            }
 632            if cursor.end(&()).row() == output_row {
 633                cursor.next(&())
 634            } else {
 635                break;
 636            }
 637        }
 638        false
 639    }
 640
 641    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 642        let start = start.to_offset(self);
 643        self.chunks(start..self.len(), false)
 644            .flat_map(|chunk| chunk.text.chars())
 645    }
 646
 647    pub fn chunks<'a>(&'a self, range: Range<FoldOffset>, language_aware: bool) -> FoldChunks<'a> {
 648        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 649
 650        transform_cursor.seek(&range.end, Bias::Right, &());
 651        let overshoot = range.end.0 - transform_cursor.start().0 .0;
 652        let buffer_end = transform_cursor.start().1 + overshoot;
 653
 654        transform_cursor.seek(&range.start, Bias::Right, &());
 655        let overshoot = range.start.0 - transform_cursor.start().0 .0;
 656        let buffer_start = transform_cursor.start().1 + overshoot;
 657
 658        FoldChunks {
 659            transform_cursor,
 660            buffer_chunks: self
 661                .buffer_snapshot
 662                .chunks(buffer_start..buffer_end, language_aware),
 663            buffer_chunk: None,
 664            buffer_offset: buffer_start,
 665            output_offset: range.start.0,
 666            max_output_offset: range.end.0,
 667        }
 668    }
 669
 670    #[cfg(test)]
 671    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 672        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 673        cursor.seek(&offset, Bias::Right, &());
 674        if let Some(transform) = cursor.item() {
 675            let transform_start = cursor.start().0 .0;
 676            if transform.output_text.is_some() {
 677                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 678                    FoldOffset(transform_start)
 679                } else {
 680                    FoldOffset(cursor.end(&()).0 .0)
 681                }
 682            } else {
 683                let overshoot = offset.0 - transform_start;
 684                let buffer_offset = cursor.start().1 + overshoot;
 685                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 686                FoldOffset(
 687                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 688                        as usize,
 689                )
 690            }
 691        } else {
 692            FoldOffset(self.transforms.summary().output.bytes)
 693        }
 694    }
 695
 696    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 697        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 698        cursor.seek(&point, Bias::Right, &());
 699        if let Some(transform) = cursor.item() {
 700            let transform_start = cursor.start().0 .0;
 701            if transform.output_text.is_some() {
 702                if point.0 == transform_start || matches!(bias, Bias::Left) {
 703                    FoldPoint(transform_start)
 704                } else {
 705                    FoldPoint(cursor.end(&()).0 .0)
 706                }
 707            } else {
 708                let overshoot = point.0 - transform_start;
 709                let buffer_position = cursor.start().1 + overshoot;
 710                let clipped_buffer_position =
 711                    self.buffer_snapshot.clip_point(buffer_position, bias);
 712                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 713            }
 714        } else {
 715            FoldPoint(self.transforms.summary().output.lines)
 716        }
 717    }
 718}
 719
 720fn intersecting_folds<'a, T>(
 721    buffer: &'a MultiBufferSnapshot,
 722    folds: &'a SumTree<Fold>,
 723    range: Range<T>,
 724    inclusive: bool,
 725) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 726where
 727    T: ToOffset,
 728{
 729    let start = buffer.anchor_before(range.start.to_offset(buffer));
 730    let end = buffer.anchor_after(range.end.to_offset(buffer));
 731    folds.filter::<_, usize>(
 732        move |summary| {
 733            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 734            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 735
 736            if inclusive {
 737                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 738            } else {
 739                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 740            }
 741        },
 742        buffer,
 743    )
 744}
 745
 746fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 747    edits.sort_unstable_by(|a, b| {
 748        a.old
 749            .start
 750            .cmp(&b.old.start)
 751            .then_with(|| b.old.end.cmp(&a.old.end))
 752    });
 753
 754    let mut i = 1;
 755    while i < edits.len() {
 756        let edit = edits[i].clone();
 757        let prev_edit = &mut edits[i - 1];
 758        if prev_edit.old.end >= edit.old.start {
 759            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 760            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 761            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 762            edits.remove(i);
 763            continue;
 764        }
 765        i += 1;
 766    }
 767}
 768
 769fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 770    edits.sort_unstable_by(|a, b| {
 771        a.old
 772            .start
 773            .cmp(&b.old.start)
 774            .then_with(|| b.old.end.cmp(&a.old.end))
 775    });
 776
 777    let mut i = 1;
 778    while i < edits.len() {
 779        let edit = edits[i].clone();
 780        let prev_edit = &mut edits[i - 1];
 781        if prev_edit.old.end >= edit.old.start {
 782            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 783            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 784            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 785            edits.remove(i);
 786            continue;
 787        }
 788        i += 1;
 789    }
 790}
 791
 792#[derive(Clone, Debug, Default, Eq, PartialEq)]
 793struct Transform {
 794    summary: TransformSummary,
 795    output_text: Option<&'static str>,
 796}
 797
 798impl Transform {
 799    fn is_fold(&self) -> bool {
 800        self.output_text.is_some()
 801    }
 802}
 803
 804#[derive(Clone, Debug, Default, Eq, PartialEq)]
 805struct TransformSummary {
 806    output: TextSummary,
 807    input: TextSummary,
 808}
 809
 810impl sum_tree::Item for Transform {
 811    type Summary = TransformSummary;
 812
 813    fn summary(&self) -> Self::Summary {
 814        self.summary.clone()
 815    }
 816}
 817
 818impl sum_tree::Summary for TransformSummary {
 819    type Context = ();
 820
 821    fn add_summary(&mut self, other: &Self, _: &()) {
 822        self.input += &other.input;
 823        self.output += &other.output;
 824    }
 825}
 826
 827#[derive(Clone, Debug)]
 828struct Fold(Range<Anchor>);
 829
 830impl Default for Fold {
 831    fn default() -> Self {
 832        Self(Anchor::min()..Anchor::max())
 833    }
 834}
 835
 836impl sum_tree::Item for Fold {
 837    type Summary = FoldSummary;
 838
 839    fn summary(&self) -> Self::Summary {
 840        FoldSummary {
 841            start: self.0.start.clone(),
 842            end: self.0.end.clone(),
 843            min_start: self.0.start.clone(),
 844            max_end: self.0.end.clone(),
 845            count: 1,
 846        }
 847    }
 848}
 849
 850#[derive(Clone, Debug)]
 851struct FoldSummary {
 852    start: Anchor,
 853    end: Anchor,
 854    min_start: Anchor,
 855    max_end: Anchor,
 856    count: usize,
 857}
 858
 859impl Default for FoldSummary {
 860    fn default() -> Self {
 861        Self {
 862            start: Anchor::min(),
 863            end: Anchor::max(),
 864            min_start: Anchor::max(),
 865            max_end: Anchor::min(),
 866            count: 0,
 867        }
 868    }
 869}
 870
 871impl sum_tree::Summary for FoldSummary {
 872    type Context = MultiBufferSnapshot;
 873
 874    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 875        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 876            self.min_start = other.min_start.clone();
 877        }
 878        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 879            self.max_end = other.max_end.clone();
 880        }
 881
 882        #[cfg(debug_assertions)]
 883        {
 884            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 885            assert!(start_comparison <= Ordering::Equal);
 886            if start_comparison == Ordering::Equal {
 887                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 888            }
 889        }
 890
 891        self.start = other.start.clone();
 892        self.end = other.end.clone();
 893        self.count += other.count;
 894    }
 895}
 896
 897impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 898    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 899        self.0.start = summary.start.clone();
 900        self.0.end = summary.end.clone();
 901    }
 902}
 903
 904impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 905    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 906        self.0.cmp(&other.0, buffer).unwrap()
 907    }
 908}
 909
 910impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 911    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 912        *self += summary.count;
 913    }
 914}
 915
 916pub struct FoldBufferRows<'a> {
 917    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 918    input_buffer_rows: MultiBufferRows<'a>,
 919    fold_point: FoldPoint,
 920}
 921
 922impl<'a> Iterator for FoldBufferRows<'a> {
 923    type Item = Option<u32>;
 924
 925    fn next(&mut self) -> Option<Self::Item> {
 926        let mut traversed_fold = false;
 927        while self.fold_point > self.cursor.end(&()).0 {
 928            self.cursor.next(&());
 929            traversed_fold = true;
 930            if self.cursor.item().is_none() {
 931                break;
 932            }
 933        }
 934
 935        if self.cursor.item().is_some() {
 936            if traversed_fold {
 937                self.input_buffer_rows.seek(self.cursor.start().1.row);
 938                self.input_buffer_rows.next();
 939            }
 940            *self.fold_point.row_mut() += 1;
 941            self.input_buffer_rows.next()
 942        } else {
 943            None
 944        }
 945    }
 946}
 947
 948pub struct FoldChunks<'a> {
 949    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 950    buffer_chunks: MultiBufferChunks<'a>,
 951    buffer_chunk: Option<(usize, Chunk<'a>)>,
 952    buffer_offset: usize,
 953    output_offset: usize,
 954    max_output_offset: usize,
 955}
 956
 957impl<'a> Iterator for FoldChunks<'a> {
 958    type Item = Chunk<'a>;
 959
 960    fn next(&mut self) -> Option<Self::Item> {
 961        if self.output_offset >= self.max_output_offset {
 962            return None;
 963        }
 964
 965        let transform = if let Some(item) = self.transform_cursor.item() {
 966            item
 967        } else {
 968            return None;
 969        };
 970
 971        // If we're in a fold, then return the fold's display text and
 972        // advance the transform and buffer cursors to the end of the fold.
 973        if let Some(output_text) = transform.output_text {
 974            self.buffer_chunk.take();
 975            self.buffer_offset += transform.summary.input.bytes;
 976            self.buffer_chunks.seek(self.buffer_offset);
 977
 978            while self.buffer_offset >= self.transform_cursor.end(&()).1
 979                && self.transform_cursor.item().is_some()
 980            {
 981                self.transform_cursor.next(&());
 982            }
 983
 984            self.output_offset += output_text.len();
 985            return Some(Chunk {
 986                text: output_text,
 987                highlight_id: None,
 988                diagnostic: None,
 989            });
 990        }
 991
 992        // Retrieve a chunk from the current location in the buffer.
 993        if self.buffer_chunk.is_none() {
 994            let chunk_offset = self.buffer_chunks.offset();
 995            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
 996        }
 997
 998        // Otherwise, take a chunk from the buffer's text.
 999        if let Some((chunk_offset, mut chunk)) = self.buffer_chunk {
1000            let offset_in_chunk = self.buffer_offset - chunk_offset;
1001            chunk.text = &chunk.text[offset_in_chunk..];
1002
1003            // Truncate the chunk so that it ends at the next fold.
1004            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
1005            if chunk.text.len() >= region_end {
1006                chunk.text = &chunk.text[0..region_end];
1007                self.transform_cursor.next(&());
1008            } else {
1009                self.buffer_chunk.take();
1010            }
1011
1012            self.buffer_offset += chunk.text.len();
1013            self.output_offset += chunk.text.len();
1014            return Some(chunk);
1015        }
1016
1017        None
1018    }
1019}
1020
1021impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1022    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1023        self.0 += &summary.output.lines;
1024    }
1025}
1026
1027#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1028pub struct FoldOffset(pub usize);
1029
1030impl FoldOffset {
1031    pub fn to_point(&self, snapshot: &FoldSnapshot) -> FoldPoint {
1032        let mut cursor = snapshot
1033            .transforms
1034            .cursor::<(FoldOffset, TransformSummary)>();
1035        cursor.seek(self, Bias::Right, &());
1036        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1037            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1038        } else {
1039            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1040            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1041            buffer_point - cursor.start().1.input.lines
1042        };
1043        FoldPoint(cursor.start().1.output.lines + overshoot)
1044    }
1045}
1046
1047impl Sub for FoldOffset {
1048    type Output = Self;
1049
1050    fn sub(self, rhs: Self) -> Self::Output {
1051        Self(self.0 - rhs.0)
1052    }
1053}
1054
1055impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1056    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1057        self.0 += &summary.output.bytes;
1058    }
1059}
1060
1061impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1062    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1063        *self += &summary.input.lines;
1064    }
1065}
1066
1067impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1068    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1069        *self += &summary.input.bytes;
1070    }
1071}
1072
1073pub type FoldEdit = Edit<FoldOffset>;
1074
1075#[cfg(test)]
1076mod tests {
1077    use super::*;
1078    use crate::{MultiBuffer, ToPoint};
1079    use rand::prelude::*;
1080    use std::{env, mem};
1081    use text::RandomCharIter;
1082    use util::test::sample_text;
1083    use Bias::{Left, Right};
1084
1085    #[gpui::test]
1086    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1087        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1088        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1089        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1090        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1091
1092        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1093        let (snapshot2, edits) = writer.fold(vec![
1094            Point::new(0, 2)..Point::new(2, 2),
1095            Point::new(2, 4)..Point::new(4, 1),
1096        ]);
1097        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1098        assert_eq!(
1099            edits,
1100            &[
1101                FoldEdit {
1102                    old: FoldOffset(2)..FoldOffset(16),
1103                    new: FoldOffset(2)..FoldOffset(5),
1104                },
1105                FoldEdit {
1106                    old: FoldOffset(18)..FoldOffset(29),
1107                    new: FoldOffset(7)..FoldOffset(10)
1108                },
1109            ]
1110        );
1111
1112        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1113            buffer.edit(
1114                vec![
1115                    Point::new(0, 0)..Point::new(0, 1),
1116                    Point::new(2, 3)..Point::new(2, 3),
1117                ],
1118                "123",
1119                cx,
1120            );
1121            buffer.snapshot(cx)
1122        });
1123        let (snapshot3, edits) =
1124            map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1125        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1126        assert_eq!(
1127            edits,
1128            &[
1129                FoldEdit {
1130                    old: FoldOffset(0)..FoldOffset(1),
1131                    new: FoldOffset(0)..FoldOffset(3),
1132                },
1133                FoldEdit {
1134                    old: FoldOffset(6)..FoldOffset(6),
1135                    new: FoldOffset(8)..FoldOffset(11),
1136                },
1137            ]
1138        );
1139
1140        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1141            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx);
1142            buffer.snapshot(cx)
1143        });
1144        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1145        assert_eq!(snapshot4.text(), "123a…c123456eee");
1146
1147        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1148        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)));
1149        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1150        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1151    }
1152
1153    #[gpui::test]
1154    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1155        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1156        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1157        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1158
1159        {
1160            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1161
1162            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1163            writer.fold(vec![5..8]);
1164            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1165            assert_eq!(snapshot.text(), "abcde…ijkl");
1166
1167            // Create an fold adjacent to the start of the first fold.
1168            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1169            writer.fold(vec![0..1, 2..5]);
1170            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1171            assert_eq!(snapshot.text(), "…b…ijkl");
1172
1173            // Create an fold adjacent to the end of the first fold.
1174            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1175            writer.fold(vec![11..11, 8..10]);
1176            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1177            assert_eq!(snapshot.text(), "…b…kl");
1178        }
1179
1180        {
1181            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1182
1183            // Create two adjacent folds.
1184            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1185            writer.fold(vec![0..2, 2..5]);
1186            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1187            assert_eq!(snapshot.text(), "…fghijkl");
1188
1189            // Edit within one of the folds.
1190            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1191                buffer.edit(vec![0..1], "12345", cx);
1192                buffer.snapshot(cx)
1193            });
1194            let (snapshot, _) =
1195                map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1196            assert_eq!(snapshot.text(), "12345…fghijkl");
1197        }
1198    }
1199
1200    #[gpui::test]
1201    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1202        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1203        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1204        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1205        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1206        writer.fold(vec![
1207            Point::new(0, 2)..Point::new(2, 2),
1208            Point::new(0, 4)..Point::new(1, 0),
1209            Point::new(1, 2)..Point::new(3, 2),
1210            Point::new(3, 1)..Point::new(4, 1),
1211        ]);
1212        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1213        assert_eq!(snapshot.text(), "aa…eeeee");
1214    }
1215
1216    #[gpui::test]
1217    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1218        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1219        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1220        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1221        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1222
1223        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1224        writer.fold(vec![
1225            Point::new(0, 2)..Point::new(2, 2),
1226            Point::new(3, 1)..Point::new(4, 1),
1227        ]);
1228        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1229        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1230
1231        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1232            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx);
1233            buffer.snapshot(cx)
1234        });
1235        let (snapshot, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1236        assert_eq!(snapshot.text(), "aa…eeeee");
1237    }
1238
1239    #[gpui::test]
1240    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1241        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1242        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1243        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1244
1245        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1246        writer.fold(vec![
1247            Point::new(0, 2)..Point::new(2, 2),
1248            Point::new(0, 4)..Point::new(1, 0),
1249            Point::new(1, 2)..Point::new(3, 2),
1250            Point::new(3, 1)..Point::new(4, 1),
1251        ]);
1252        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1253        let fold_ranges = snapshot
1254            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1255            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1256            .collect::<Vec<_>>();
1257        assert_eq!(
1258            fold_ranges,
1259            vec![
1260                Point::new(0, 2)..Point::new(2, 2),
1261                Point::new(1, 2)..Point::new(3, 2)
1262            ]
1263        );
1264    }
1265
1266    #[gpui::test(iterations = 100)]
1267    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1268        let operations = env::var("OPERATIONS")
1269            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1270            .unwrap_or(10);
1271
1272        let len = rng.gen_range(0..10);
1273        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1274        let buffer = if rng.gen() {
1275            MultiBuffer::build_simple(&text, cx)
1276        } else {
1277            MultiBuffer::build_random(&mut rng, cx)
1278        };
1279        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1280        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1281
1282        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1283        let mut snapshot_edits = Vec::new();
1284
1285        for _ in 0..operations {
1286            log::info!("text: {:?}", buffer_snapshot.text());
1287            let mut buffer_edits = Vec::new();
1288            match rng.gen_range(0..=100) {
1289                0..=59 => {
1290                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1291                }
1292                _ => buffer.update(cx, |buffer, cx| {
1293                    let subscription = buffer.subscribe();
1294                    let edit_count = rng.gen_range(1..=5);
1295                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1296                    buffer_snapshot = buffer.snapshot(cx);
1297                    let edits = subscription.consume().into_inner();
1298                    log::info!("editing {:?}", edits);
1299                    buffer_edits.extend(edits);
1300                }),
1301            };
1302
1303            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1304            snapshot_edits.push((snapshot.clone(), edits));
1305
1306            let mut expected_text: String = buffer_snapshot.text().to_string();
1307            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1308                expected_text.replace_range(fold_range.start..fold_range.end, "…");
1309            }
1310
1311            assert_eq!(snapshot.text(), expected_text);
1312            log::info!(
1313                "fold text {:?} ({} lines)",
1314                expected_text,
1315                expected_text.matches('\n').count() + 1
1316            );
1317
1318            let mut prev_row = 0;
1319            let mut expected_buffer_rows = Vec::new();
1320            for fold_range in map.merged_fold_ranges().into_iter() {
1321                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1322                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1323                expected_buffer_rows.extend(
1324                    buffer_snapshot
1325                        .buffer_rows(prev_row)
1326                        .take((1 + fold_start - prev_row) as usize),
1327                );
1328                prev_row = 1 + fold_end;
1329            }
1330            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1331
1332            assert_eq!(
1333                expected_buffer_rows.len(),
1334                expected_text.matches('\n').count() + 1,
1335                "wrong expected buffer rows {:?}. text: {:?}",
1336                expected_buffer_rows,
1337                expected_text
1338            );
1339
1340            for (output_row, line) in expected_text.lines().enumerate() {
1341                let line_len = snapshot.line_len(output_row as u32);
1342                assert_eq!(line_len, line.len() as u32);
1343            }
1344
1345            let longest_row = snapshot.longest_row();
1346            let longest_char_column = expected_text
1347                .split('\n')
1348                .nth(longest_row as usize)
1349                .unwrap()
1350                .chars()
1351                .count();
1352            let mut fold_point = FoldPoint::new(0, 0);
1353            let mut fold_offset = FoldOffset(0);
1354            let mut char_column = 0;
1355            for c in expected_text.chars() {
1356                let buffer_point = fold_point.to_buffer_point(&snapshot);
1357                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1358                assert_eq!(
1359                    buffer_point.to_fold_point(&snapshot, Right),
1360                    fold_point,
1361                    "{:?} -> fold point",
1362                    buffer_point,
1363                );
1364                assert_eq!(
1365                    fold_point.to_buffer_offset(&snapshot),
1366                    buffer_offset,
1367                    "fold_point.to_buffer_offset({:?})",
1368                    fold_point,
1369                );
1370                assert_eq!(
1371                    fold_point.to_offset(&snapshot),
1372                    fold_offset,
1373                    "fold_point.to_offset({:?})",
1374                    fold_point,
1375                );
1376
1377                if c == '\n' {
1378                    *fold_point.row_mut() += 1;
1379                    *fold_point.column_mut() = 0;
1380                    char_column = 0;
1381                } else {
1382                    *fold_point.column_mut() += c.len_utf8() as u32;
1383                    char_column += 1;
1384                }
1385                fold_offset.0 += c.len_utf8();
1386                if char_column > longest_char_column {
1387                    panic!(
1388                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1389                        longest_row,
1390                        longest_char_column,
1391                        fold_point.row(),
1392                        char_column
1393                    );
1394                }
1395            }
1396
1397            for _ in 0..5 {
1398                let mut start = snapshot
1399                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1400                let mut end = snapshot
1401                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1402                if start > end {
1403                    mem::swap(&mut start, &mut end);
1404                }
1405
1406                let text = &expected_text[start.0..end.0];
1407                assert_eq!(
1408                    snapshot
1409                        .chunks(start..end, false)
1410                        .map(|c| c.text)
1411                        .collect::<String>(),
1412                    text,
1413                );
1414            }
1415
1416            let mut fold_row = 0;
1417            while fold_row < expected_buffer_rows.len() as u32 {
1418                fold_row = snapshot
1419                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1420                    .row();
1421                assert_eq!(
1422                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1423                    expected_buffer_rows[(fold_row as usize)..],
1424                    "wrong buffer rows starting at fold row {}",
1425                    fold_row,
1426                );
1427                fold_row += 1;
1428            }
1429
1430            for fold_range in map.merged_fold_ranges() {
1431                let fold_point = fold_range
1432                    .start
1433                    .to_point(&buffer_snapshot)
1434                    .to_fold_point(&snapshot, Right);
1435                assert!(snapshot.is_line_folded(fold_point.row()));
1436            }
1437
1438            for _ in 0..5 {
1439                let end =
1440                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1441                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1442                let expected_folds = map
1443                    .folds
1444                    .items(&buffer_snapshot)
1445                    .into_iter()
1446                    .filter(|fold| {
1447                        let start = buffer_snapshot.anchor_before(start);
1448                        let end = buffer_snapshot.anchor_after(end);
1449                        start.cmp(&fold.0.end, &buffer_snapshot).unwrap() == Ordering::Less
1450                            && end.cmp(&fold.0.start, &buffer_snapshot).unwrap()
1451                                == Ordering::Greater
1452                    })
1453                    .map(|fold| fold.0)
1454                    .collect::<Vec<_>>();
1455
1456                assert_eq!(
1457                    snapshot
1458                        .folds_in_range(start..end)
1459                        .cloned()
1460                        .collect::<Vec<_>>(),
1461                    expected_folds
1462                );
1463            }
1464
1465            let text = snapshot.text();
1466            for _ in 0..5 {
1467                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1468                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1469                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1470                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1471                let mut start =
1472                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1473                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1474                if start > end {
1475                    mem::swap(&mut start, &mut end);
1476                }
1477
1478                let lines = start..end;
1479                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1480                assert_eq!(
1481                    snapshot.text_summary_for_range(lines),
1482                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1483                )
1484            }
1485
1486            let mut text = initial_snapshot.text();
1487            for (snapshot, edits) in snapshot_edits.drain(..) {
1488                let new_text = snapshot.text();
1489                for edit in edits {
1490                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1491                    let new_bytes = edit.new.start.0..edit.new.end.0;
1492                    text.replace_range(old_bytes, &new_text[new_bytes]);
1493                }
1494
1495                assert_eq!(text, new_text);
1496                initial_snapshot = snapshot;
1497            }
1498        }
1499    }
1500
1501    #[gpui::test]
1502    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1503        let text = sample_text(6, 6, 'a') + "\n";
1504        let buffer = MultiBuffer::build_simple(&text, cx);
1505
1506        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1507        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1508
1509        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1510        writer.fold(vec![
1511            Point::new(0, 2)..Point::new(2, 2),
1512            Point::new(3, 1)..Point::new(4, 1),
1513        ]);
1514
1515        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1516        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1517        assert_eq!(
1518            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1519            [Some(0), Some(3), Some(5), Some(6)]
1520        );
1521        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1522    }
1523
1524    impl FoldMap {
1525        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1526            let buffer = self.buffer.lock().clone();
1527            let mut folds = self.folds.items(&buffer);
1528            // Ensure sorting doesn't change how folds get merged and displayed.
1529            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1530            let mut fold_ranges = folds
1531                .iter()
1532                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1533                .peekable();
1534
1535            let mut merged_ranges = Vec::new();
1536            while let Some(mut fold_range) = fold_ranges.next() {
1537                while let Some(next_range) = fold_ranges.peek() {
1538                    if fold_range.end >= next_range.start {
1539                        if next_range.end > fold_range.end {
1540                            fold_range.end = next_range.end;
1541                        }
1542                        fold_ranges.next();
1543                    } else {
1544                        break;
1545                    }
1546                }
1547                if fold_range.end > fold_range.start {
1548                    merged_ranges.push(fold_range);
1549                }
1550            }
1551            merged_ranges
1552        }
1553
1554        pub fn randomly_mutate(
1555            &mut self,
1556            rng: &mut impl Rng,
1557        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1558            let mut snapshot_edits = Vec::new();
1559            match rng.gen_range(0..=100) {
1560                0..=39 if !self.folds.is_empty() => {
1561                    let buffer = self.buffer.lock().clone();
1562                    let mut to_unfold = Vec::new();
1563                    for _ in 0..rng.gen_range(1..=3) {
1564                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1565                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1566                        to_unfold.push(start..end);
1567                    }
1568                    log::info!("unfolding {:?}", to_unfold);
1569                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1570                    snapshot_edits.push((snapshot, edits));
1571                    let (snapshot, edits) = writer.fold(to_unfold);
1572                    snapshot_edits.push((snapshot, edits));
1573                }
1574                _ => {
1575                    let buffer = self.buffer.lock().clone();
1576                    let mut to_fold = Vec::new();
1577                    for _ in 0..rng.gen_range(1..=2) {
1578                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1579                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1580                        to_fold.push(start..end);
1581                    }
1582                    log::info!("folding {:?}", to_fold);
1583                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1584                    snapshot_edits.push((snapshot, edits));
1585                    let (snapshot, edits) = writer.fold(to_fold);
1586                    snapshot_edits.push((snapshot, edits));
1587                }
1588            }
1589            snapshot_edits
1590        }
1591    }
1592}