fold_map.rs

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