1use super::TextHighlights;
   2use crate::{
   3    multi_buffer::MultiBufferRows, Anchor, AnchorRangeExt, MultiBufferChunks, MultiBufferSnapshot,
   4    ToOffset,
   5};
   6use collections::BTreeMap;
   7use gpui::fonts::HighlightStyle;
   8use language::{Chunk, Edit, Point, PointUtf16, TextSummary};
   9use parking_lot::Mutex;
  10use std::{
  11    any::TypeId,
  12    cmp::{self, Ordering},
  13    iter::{self, Peekable},
  14    ops::{Range, Sub},
  15    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  16    vec,
  17};
  18use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  19
  20#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  21pub struct FoldPoint(pub super::Point);
  22
  23impl FoldPoint {
  24    pub fn new(row: u32, column: u32) -> Self {
  25        Self(super::Point::new(row, column))
  26    }
  27
  28    pub fn row(self) -> u32 {
  29        self.0.row
  30    }
  31
  32    pub fn column(self) -> u32 {
  33        self.0.column
  34    }
  35
  36    pub fn row_mut(&mut self) -> &mut u32 {
  37        &mut self.0.row
  38    }
  39
  40    pub fn column_mut(&mut self) -> &mut u32 {
  41        &mut self.0.column
  42    }
  43
  44    pub fn to_buffer_point(&self, snapshot: &FoldSnapshot) -> Point {
  45        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  46        cursor.seek(self, Bias::Right, &());
  47        let overshoot = self.0 - cursor.start().0 .0;
  48        cursor.start().1 + overshoot
  49    }
  50
  51    pub fn to_buffer_offset(&self, snapshot: &FoldSnapshot) -> usize {
  52        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  53        cursor.seek(self, Bias::Right, &());
  54        let overshoot = self.0 - cursor.start().0 .0;
  55        snapshot
  56            .buffer_snapshot
  57            .point_to_offset(cursor.start().1 + overshoot)
  58    }
  59
  60    pub fn to_offset(&self, snapshot: &FoldSnapshot) -> FoldOffset {
  61        let mut cursor = snapshot
  62            .transforms
  63            .cursor::<(FoldPoint, TransformSummary)>();
  64        cursor.seek(self, Bias::Right, &());
  65        let overshoot = self.0 - cursor.start().1.output.lines;
  66        let mut offset = cursor.start().1.output.bytes;
  67        if !overshoot.is_zero() {
  68            let transform = cursor.item().expect("display point out of range");
  69            assert!(transform.output_text.is_none());
  70            let end_buffer_offset = snapshot
  71                .buffer_snapshot
  72                .point_to_offset(cursor.start().1.input.lines + overshoot);
  73            offset += end_buffer_offset - cursor.start().1.input.bytes;
  74        }
  75        FoldOffset(offset)
  76    }
  77}
  78
  79impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
  80    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
  81        self.0 += &summary.output.lines;
  82    }
  83}
  84
  85pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  86
  87impl<'a> FoldMapWriter<'a> {
  88    pub fn fold<T: ToOffset>(
  89        &mut self,
  90        ranges: impl IntoIterator<Item = Range<T>>,
  91    ) -> (FoldSnapshot, Vec<FoldEdit>) {
  92        let mut edits = Vec::new();
  93        let mut folds = Vec::new();
  94        let buffer = self.0.buffer.lock().clone();
  95        for range in ranges.into_iter() {
  96            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
  97
  98            // Ignore any empty ranges.
  99            if range.start == range.end {
 100                continue;
 101            }
 102
 103            // For now, ignore any ranges that span an excerpt boundary.
 104            let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 105            if fold.0.start.excerpt_id() != fold.0.end.excerpt_id() {
 106                continue;
 107            }
 108
 109            folds.push(fold);
 110            edits.push(text::Edit {
 111                old: range.clone(),
 112                new: range,
 113            });
 114        }
 115
 116        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 117
 118        self.0.folds = {
 119            let mut new_tree = SumTree::new();
 120            let mut cursor = self.0.folds.cursor::<Fold>();
 121            for fold in folds {
 122                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 123                new_tree.push(fold, &buffer);
 124            }
 125            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 126            new_tree
 127        };
 128
 129        consolidate_buffer_edits(&mut edits);
 130        let edits = self.0.sync(buffer.clone(), edits);
 131        let snapshot = FoldSnapshot {
 132            transforms: self.0.transforms.lock().clone(),
 133            folds: self.0.folds.clone(),
 134            buffer_snapshot: buffer,
 135            version: self.0.version.load(SeqCst),
 136        };
 137        (snapshot, edits)
 138    }
 139
 140    pub fn unfold<T: ToOffset>(
 141        &mut self,
 142        ranges: impl IntoIterator<Item = Range<T>>,
 143        inclusive: bool,
 144    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 145        let mut edits = Vec::new();
 146        let mut fold_ixs_to_delete = Vec::new();
 147        let buffer = self.0.buffer.lock().clone();
 148        for range in ranges.into_iter() {
 149            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 150            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, inclusive);
 151            while let Some(fold) = folds_cursor.item() {
 152                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 153                if offset_range.end > offset_range.start {
 154                    edits.push(text::Edit {
 155                        old: offset_range.clone(),
 156                        new: offset_range,
 157                    });
 158                }
 159                fold_ixs_to_delete.push(*folds_cursor.start());
 160                folds_cursor.next(&buffer);
 161            }
 162        }
 163
 164        fold_ixs_to_delete.sort_unstable();
 165        fold_ixs_to_delete.dedup();
 166
 167        self.0.folds = {
 168            let mut cursor = self.0.folds.cursor::<usize>();
 169            let mut folds = SumTree::new();
 170            for fold_ix in fold_ixs_to_delete {
 171                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 172                cursor.next(&buffer);
 173            }
 174            folds.push_tree(cursor.suffix(&buffer), &buffer);
 175            folds
 176        };
 177
 178        consolidate_buffer_edits(&mut edits);
 179        let edits = self.0.sync(buffer.clone(), edits);
 180        let snapshot = FoldSnapshot {
 181            transforms: self.0.transforms.lock().clone(),
 182            folds: self.0.folds.clone(),
 183            buffer_snapshot: buffer,
 184            version: self.0.version.load(SeqCst),
 185        };
 186        (snapshot, edits)
 187    }
 188}
 189
 190pub struct FoldMap {
 191    buffer: Mutex<MultiBufferSnapshot>,
 192    transforms: Mutex<SumTree<Transform>>,
 193    folds: SumTree<Fold>,
 194    version: AtomicUsize,
 195}
 196
 197impl FoldMap {
 198    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 199        let this = Self {
 200            buffer: Mutex::new(buffer.clone()),
 201            folds: Default::default(),
 202            transforms: Mutex::new(SumTree::from_item(
 203                Transform {
 204                    summary: TransformSummary {
 205                        input: buffer.text_summary(),
 206                        output: buffer.text_summary(),
 207                    },
 208                    output_text: None,
 209                },
 210                &(),
 211            )),
 212            version: Default::default(),
 213        };
 214
 215        let snapshot = FoldSnapshot {
 216            transforms: this.transforms.lock().clone(),
 217            folds: this.folds.clone(),
 218            buffer_snapshot: this.buffer.lock().clone(),
 219            version: this.version.load(SeqCst),
 220        };
 221        (this, snapshot)
 222    }
 223
 224    pub fn read(
 225        &self,
 226        buffer: MultiBufferSnapshot,
 227        edits: Vec<Edit<usize>>,
 228    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 229        let edits = self.sync(buffer, edits);
 230        self.check_invariants();
 231        let snapshot = FoldSnapshot {
 232            transforms: self.transforms.lock().clone(),
 233            folds: self.folds.clone(),
 234            buffer_snapshot: self.buffer.lock().clone(),
 235            version: self.version.load(SeqCst),
 236        };
 237        (snapshot, edits)
 238    }
 239
 240    pub fn write(
 241        &mut self,
 242        buffer: MultiBufferSnapshot,
 243        edits: Vec<Edit<usize>>,
 244    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 245        let (snapshot, edits) = self.read(buffer, edits);
 246        (FoldMapWriter(self), snapshot, edits)
 247    }
 248
 249    fn check_invariants(&self) {
 250        if cfg!(test) {
 251            assert_eq!(
 252                self.transforms.lock().summary().input.bytes,
 253                self.buffer.lock().len(),
 254                "transform tree does not match buffer's length"
 255            );
 256
 257            let mut folds = self.folds.iter().peekable();
 258            while let Some(fold) = folds.next() {
 259                if let Some(next_fold) = folds.peek() {
 260                    let comparison = fold.0.cmp(&next_fold.0, &self.buffer.lock()).unwrap();
 261                    assert!(comparison.is_le());
 262                }
 263            }
 264        }
 265    }
 266
 267    fn sync(
 268        &self,
 269        new_buffer: MultiBufferSnapshot,
 270        buffer_edits: Vec<text::Edit<usize>>,
 271    ) -> Vec<FoldEdit> {
 272        if buffer_edits.is_empty() {
 273            let mut buffer = self.buffer.lock();
 274            if buffer.parse_count() != new_buffer.parse_count()
 275                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 276                || buffer.trailing_excerpt_update_count()
 277                    != new_buffer.trailing_excerpt_update_count()
 278            {
 279                self.version.fetch_add(1, SeqCst);
 280            }
 281            *buffer = new_buffer;
 282            Vec::new()
 283        } else {
 284            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 285
 286            let mut new_transforms = SumTree::new();
 287            let mut transforms = self.transforms.lock();
 288            let mut cursor = transforms.cursor::<usize>();
 289            cursor.seek(&0, Bias::Right, &());
 290
 291            while let Some(mut edit) = buffer_edits_iter.next() {
 292                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 293                edit.new.start -= edit.old.start - cursor.start();
 294                edit.old.start = *cursor.start();
 295
 296                cursor.seek(&edit.old.end, Bias::Right, &());
 297                cursor.next(&());
 298
 299                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 300                loop {
 301                    edit.old.end = *cursor.start();
 302
 303                    if let Some(next_edit) = buffer_edits_iter.peek() {
 304                        if next_edit.old.start > edit.old.end {
 305                            break;
 306                        }
 307
 308                        let next_edit = buffer_edits_iter.next().unwrap();
 309                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 310
 311                        if next_edit.old.end >= edit.old.end {
 312                            edit.old.end = next_edit.old.end;
 313                            cursor.seek(&edit.old.end, Bias::Right, &());
 314                            cursor.next(&());
 315                        }
 316                    } else {
 317                        break;
 318                    }
 319                }
 320
 321                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 322
 323                let anchor = new_buffer.anchor_before(edit.new.start);
 324                let mut folds_cursor = self.folds.cursor::<Fold>();
 325                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 326
 327                let mut folds = iter::from_fn({
 328                    let buffer = &new_buffer;
 329                    move || {
 330                        let item = folds_cursor
 331                            .item()
 332                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 333                        folds_cursor.next(buffer);
 334                        item
 335                    }
 336                })
 337                .peekable();
 338
 339                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 340                    let mut fold = folds.next().unwrap();
 341                    let sum = new_transforms.summary();
 342
 343                    assert!(fold.start >= sum.input.bytes);
 344
 345                    while folds
 346                        .peek()
 347                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 348                    {
 349                        let next_fold = folds.next().unwrap();
 350                        if next_fold.end > fold.end {
 351                            fold.end = next_fold.end;
 352                        }
 353                    }
 354
 355                    if fold.start > sum.input.bytes {
 356                        let text_summary = new_buffer
 357                            .text_summary_for_range::<TextSummary, _>(sum.input.bytes..fold.start);
 358                        new_transforms.push(
 359                            Transform {
 360                                summary: TransformSummary {
 361                                    output: text_summary.clone(),
 362                                    input: text_summary,
 363                                },
 364                                output_text: None,
 365                            },
 366                            &(),
 367                        );
 368                    }
 369
 370                    if fold.end > fold.start {
 371                        let output_text = "…";
 372                        let chars = output_text.chars().count() as u32;
 373                        let lines = Point::new(0, output_text.len() as u32);
 374                        let lines_utf16 =
 375                            PointUtf16::new(0, output_text.encode_utf16().count() as u32);
 376                        new_transforms.push(
 377                            Transform {
 378                                summary: TransformSummary {
 379                                    output: TextSummary {
 380                                        bytes: output_text.len(),
 381                                        lines,
 382                                        lines_utf16,
 383                                        first_line_chars: chars,
 384                                        last_line_chars: chars,
 385                                        longest_row: 0,
 386                                        longest_row_chars: chars,
 387                                    },
 388                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 389                                },
 390                                output_text: Some(output_text),
 391                            },
 392                            &(),
 393                        );
 394                    }
 395                }
 396
 397                let sum = new_transforms.summary();
 398                if sum.input.bytes < edit.new.end {
 399                    let text_summary = new_buffer
 400                        .text_summary_for_range::<TextSummary, _>(sum.input.bytes..edit.new.end);
 401                    new_transforms.push(
 402                        Transform {
 403                            summary: TransformSummary {
 404                                output: text_summary.clone(),
 405                                input: text_summary,
 406                            },
 407                            output_text: None,
 408                        },
 409                        &(),
 410                    );
 411                }
 412            }
 413
 414            new_transforms.push_tree(cursor.suffix(&()), &());
 415            if new_transforms.is_empty() {
 416                let text_summary = new_buffer.text_summary();
 417                new_transforms.push(
 418                    Transform {
 419                        summary: TransformSummary {
 420                            output: text_summary.clone(),
 421                            input: text_summary,
 422                        },
 423                        output_text: None,
 424                    },
 425                    &(),
 426                );
 427            }
 428
 429            drop(cursor);
 430
 431            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 432            {
 433                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 434                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 435
 436                for mut edit in buffer_edits {
 437                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 438                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 439                        edit.old.start = old_transforms.start().0;
 440                    }
 441                    let old_start =
 442                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 443
 444                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 445                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 446                        old_transforms.next(&());
 447                        edit.old.end = old_transforms.start().0;
 448                    }
 449                    let old_end =
 450                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 451
 452                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 453                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 454                        edit.new.start = new_transforms.start().0;
 455                    }
 456                    let new_start =
 457                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 458
 459                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 460                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 461                        new_transforms.next(&());
 462                        edit.new.end = new_transforms.start().0;
 463                    }
 464                    let new_end =
 465                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 466
 467                    fold_edits.push(FoldEdit {
 468                        old: FoldOffset(old_start)..FoldOffset(old_end),
 469                        new: FoldOffset(new_start)..FoldOffset(new_end),
 470                    });
 471                }
 472
 473                consolidate_fold_edits(&mut fold_edits);
 474            }
 475
 476            *transforms = new_transforms;
 477            *self.buffer.lock() = new_buffer;
 478            self.version.fetch_add(1, SeqCst);
 479            fold_edits
 480        }
 481    }
 482}
 483
 484#[derive(Clone)]
 485pub struct FoldSnapshot {
 486    transforms: SumTree<Transform>,
 487    folds: SumTree<Fold>,
 488    buffer_snapshot: MultiBufferSnapshot,
 489    pub version: usize,
 490}
 491
 492impl FoldSnapshot {
 493    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 494        &self.buffer_snapshot
 495    }
 496
 497    #[cfg(test)]
 498    pub fn text(&self) -> String {
 499        self.chunks(FoldOffset(0)..self.len(), false, None)
 500            .map(|c| c.text)
 501            .collect()
 502    }
 503
 504    #[cfg(test)]
 505    pub fn fold_count(&self) -> usize {
 506        self.folds.items(&self.buffer_snapshot).len()
 507    }
 508
 509    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 510        let mut summary = TextSummary::default();
 511
 512        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 513        cursor.seek(&range.start, Bias::Right, &());
 514        if let Some(transform) = cursor.item() {
 515            let start_in_transform = range.start.0 - cursor.start().0 .0;
 516            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 517            if let Some(output_text) = transform.output_text {
 518                summary = TextSummary::from(
 519                    &output_text
 520                        [start_in_transform.column as usize..end_in_transform.column as usize],
 521                );
 522            } else {
 523                let buffer_start = cursor.start().1 + start_in_transform;
 524                let buffer_end = cursor.start().1 + end_in_transform;
 525                summary = self
 526                    .buffer_snapshot
 527                    .text_summary_for_range(buffer_start..buffer_end);
 528            }
 529        }
 530
 531        if range.end > cursor.end(&()).0 {
 532            cursor.next(&());
 533            summary += &cursor
 534                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 535                .output;
 536            if let Some(transform) = cursor.item() {
 537                let end_in_transform = range.end.0 - cursor.start().0 .0;
 538                if let Some(output_text) = transform.output_text {
 539                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 540                } else {
 541                    let buffer_start = cursor.start().1;
 542                    let buffer_end = cursor.start().1 + end_in_transform;
 543                    summary += self
 544                        .buffer_snapshot
 545                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 546                }
 547            }
 548        }
 549
 550        summary
 551    }
 552
 553    pub fn to_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
 554        let mut cursor = self.transforms.cursor::<(Point, FoldPoint)>();
 555        cursor.seek(&point, Bias::Right, &());
 556        if cursor.item().map_or(false, |t| t.is_fold()) {
 557            if bias == Bias::Left || point == cursor.start().0 {
 558                cursor.start().1
 559            } else {
 560                cursor.end(&()).1
 561            }
 562        } else {
 563            let overshoot = point - cursor.start().0;
 564            FoldPoint(cmp::min(
 565                cursor.start().1 .0 + overshoot,
 566                cursor.end(&()).1 .0,
 567            ))
 568        }
 569    }
 570
 571    pub fn len(&self) -> FoldOffset {
 572        FoldOffset(self.transforms.summary().output.bytes)
 573    }
 574
 575    pub fn line_len(&self, row: u32) -> u32 {
 576        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 577        let line_end = if row >= self.max_point().row() {
 578            self.len().0
 579        } else {
 580            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 581        };
 582        (line_end - line_start) as u32
 583    }
 584
 585    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 586        if start_row > self.transforms.summary().output.lines.row {
 587            panic!("invalid display row {}", start_row);
 588        }
 589
 590        let fold_point = FoldPoint::new(start_row, 0);
 591        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 592        cursor.seek(&fold_point, Bias::Left, &());
 593
 594        let overshoot = fold_point.0 - cursor.start().0 .0;
 595        let buffer_point = cursor.start().1 + overshoot;
 596        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 597
 598        FoldBufferRows {
 599            fold_point,
 600            input_buffer_rows,
 601            cursor,
 602        }
 603    }
 604
 605    pub fn max_point(&self) -> FoldPoint {
 606        FoldPoint(self.transforms.summary().output.lines)
 607    }
 608
 609    #[cfg(test)]
 610    pub fn longest_row(&self) -> u32 {
 611        self.transforms.summary().output.longest_row
 612    }
 613
 614    pub fn folds_in_range<'a, T>(
 615        &'a self,
 616        range: Range<T>,
 617    ) -> impl Iterator<Item = &'a Range<Anchor>>
 618    where
 619        T: ToOffset,
 620    {
 621        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 622        iter::from_fn(move || {
 623            let item = folds.item().map(|f| &f.0);
 624            folds.next(&self.buffer_snapshot);
 625            item
 626        })
 627    }
 628
 629    pub fn intersects_fold<T>(&self, offset: T) -> bool
 630    where
 631        T: ToOffset,
 632    {
 633        let offset = offset.to_offset(&self.buffer_snapshot);
 634        let mut cursor = self.transforms.cursor::<usize>();
 635        cursor.seek(&offset, Bias::Right, &());
 636        cursor.item().map_or(false, |t| t.output_text.is_some())
 637    }
 638
 639    pub fn is_line_folded(&self, output_row: u32) -> bool {
 640        let mut cursor = self.transforms.cursor::<FoldPoint>();
 641        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 642        while let Some(transform) = cursor.item() {
 643            if transform.output_text.is_some() {
 644                return true;
 645            }
 646            if cursor.end(&()).row() == output_row {
 647                cursor.next(&())
 648            } else {
 649                break;
 650            }
 651        }
 652        false
 653    }
 654
 655    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 656        let start = start.to_offset(self);
 657        self.chunks(start..self.len(), false, None)
 658            .flat_map(|chunk| chunk.text.chars())
 659    }
 660
 661    pub fn chunks<'a>(
 662        &'a self,
 663        range: Range<FoldOffset>,
 664        language_aware: bool,
 665        text_highlights: Option<&'a TextHighlights>,
 666    ) -> FoldChunks<'a> {
 667        let mut highlight_endpoints = Vec::new();
 668        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 669
 670        let buffer_end = {
 671            transform_cursor.seek(&range.end, Bias::Right, &());
 672            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 673            transform_cursor.start().1 + overshoot
 674        };
 675
 676        let buffer_start = {
 677            transform_cursor.seek(&range.start, Bias::Right, &());
 678            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 679            transform_cursor.start().1 + overshoot
 680        };
 681
 682        if let Some(text_highlights) = text_highlights {
 683            if !text_highlights.is_empty() {
 684                while transform_cursor.start().0 < range.end {
 685                    if !transform_cursor.item().unwrap().is_fold() {
 686                        let transform_start = self
 687                            .buffer_snapshot
 688                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 689
 690                        let transform_end = {
 691                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 692                            self.buffer_snapshot.anchor_before(cmp::min(
 693                                transform_cursor.end(&()).1,
 694                                transform_cursor.start().1 + overshoot,
 695                            ))
 696                        };
 697
 698                        for (tag, highlights) in text_highlights.iter() {
 699                            let style = highlights.0;
 700                            let ranges = &highlights.1;
 701
 702                            let start_ix = match ranges.binary_search_by(|probe| {
 703                                let cmp = probe
 704                                    .end
 705                                    .cmp(&transform_start, &self.buffer_snapshot())
 706                                    .unwrap();
 707                                if cmp.is_gt() {
 708                                    Ordering::Greater
 709                                } else {
 710                                    Ordering::Less
 711                                }
 712                            }) {
 713                                Ok(i) | Err(i) => i,
 714                            };
 715                            for range in &ranges[start_ix..] {
 716                                if range
 717                                    .start
 718                                    .cmp(&transform_end, &self.buffer_snapshot)
 719                                    .unwrap()
 720                                    .is_ge()
 721                                {
 722                                    break;
 723                                }
 724
 725                                highlight_endpoints.push(HighlightEndpoint {
 726                                    offset: range.start.to_offset(&self.buffer_snapshot),
 727                                    is_start: true,
 728                                    tag: *tag,
 729                                    style,
 730                                });
 731                                highlight_endpoints.push(HighlightEndpoint {
 732                                    offset: range.end.to_offset(&self.buffer_snapshot),
 733                                    is_start: false,
 734                                    tag: *tag,
 735                                    style,
 736                                });
 737                            }
 738                        }
 739                    }
 740
 741                    transform_cursor.next(&());
 742                }
 743                highlight_endpoints.sort();
 744                transform_cursor.seek(&range.start, Bias::Right, &());
 745            }
 746        }
 747
 748        FoldChunks {
 749            transform_cursor,
 750            buffer_chunks: self
 751                .buffer_snapshot
 752                .chunks(buffer_start..buffer_end, language_aware),
 753            buffer_chunk: None,
 754            buffer_offset: buffer_start,
 755            output_offset: range.start.0,
 756            max_output_offset: range.end.0,
 757            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 758            active_highlights: Default::default(),
 759        }
 760    }
 761
 762    #[cfg(test)]
 763    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 764        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 765        cursor.seek(&offset, Bias::Right, &());
 766        if let Some(transform) = cursor.item() {
 767            let transform_start = cursor.start().0 .0;
 768            if transform.output_text.is_some() {
 769                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 770                    FoldOffset(transform_start)
 771                } else {
 772                    FoldOffset(cursor.end(&()).0 .0)
 773                }
 774            } else {
 775                let overshoot = offset.0 - transform_start;
 776                let buffer_offset = cursor.start().1 + overshoot;
 777                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 778                FoldOffset(
 779                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 780                        as usize,
 781                )
 782            }
 783        } else {
 784            FoldOffset(self.transforms.summary().output.bytes)
 785        }
 786    }
 787
 788    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 789        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 790        cursor.seek(&point, Bias::Right, &());
 791        if let Some(transform) = cursor.item() {
 792            let transform_start = cursor.start().0 .0;
 793            if transform.output_text.is_some() {
 794                if point.0 == transform_start || matches!(bias, Bias::Left) {
 795                    FoldPoint(transform_start)
 796                } else {
 797                    FoldPoint(cursor.end(&()).0 .0)
 798                }
 799            } else {
 800                let overshoot = point.0 - transform_start;
 801                let buffer_position = cursor.start().1 + overshoot;
 802                let clipped_buffer_position =
 803                    self.buffer_snapshot.clip_point(buffer_position, bias);
 804                FoldPoint(cursor.start().0 .0 + (clipped_buffer_position - cursor.start().1))
 805            }
 806        } else {
 807            FoldPoint(self.transforms.summary().output.lines)
 808        }
 809    }
 810}
 811
 812fn intersecting_folds<'a, T>(
 813    buffer: &'a MultiBufferSnapshot,
 814    folds: &'a SumTree<Fold>,
 815    range: Range<T>,
 816    inclusive: bool,
 817) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 818where
 819    T: ToOffset,
 820{
 821    let start = buffer.anchor_before(range.start.to_offset(buffer));
 822    let end = buffer.anchor_after(range.end.to_offset(buffer));
 823    let mut cursor = folds.filter::<_, usize>(move |summary| {
 824        let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 825        let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 826
 827        if inclusive {
 828            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 829        } else {
 830            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 831        }
 832    });
 833    cursor.next(buffer);
 834    cursor
 835}
 836
 837fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 838    edits.sort_unstable_by(|a, b| {
 839        a.old
 840            .start
 841            .cmp(&b.old.start)
 842            .then_with(|| b.old.end.cmp(&a.old.end))
 843    });
 844
 845    let mut i = 1;
 846    while i < edits.len() {
 847        let edit = edits[i].clone();
 848        let prev_edit = &mut edits[i - 1];
 849        if prev_edit.old.end >= edit.old.start {
 850            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 851            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 852            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 853            edits.remove(i);
 854            continue;
 855        }
 856        i += 1;
 857    }
 858}
 859
 860fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 861    edits.sort_unstable_by(|a, b| {
 862        a.old
 863            .start
 864            .cmp(&b.old.start)
 865            .then_with(|| b.old.end.cmp(&a.old.end))
 866    });
 867
 868    let mut i = 1;
 869    while i < edits.len() {
 870        let edit = edits[i].clone();
 871        let prev_edit = &mut edits[i - 1];
 872        if prev_edit.old.end >= edit.old.start {
 873            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 874            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 875            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 876            edits.remove(i);
 877            continue;
 878        }
 879        i += 1;
 880    }
 881}
 882
 883#[derive(Clone, Debug, Default, Eq, PartialEq)]
 884struct Transform {
 885    summary: TransformSummary,
 886    output_text: Option<&'static str>,
 887}
 888
 889impl Transform {
 890    fn is_fold(&self) -> bool {
 891        self.output_text.is_some()
 892    }
 893}
 894
 895#[derive(Clone, Debug, Default, Eq, PartialEq)]
 896struct TransformSummary {
 897    output: TextSummary,
 898    input: TextSummary,
 899}
 900
 901impl sum_tree::Item for Transform {
 902    type Summary = TransformSummary;
 903
 904    fn summary(&self) -> Self::Summary {
 905        self.summary.clone()
 906    }
 907}
 908
 909impl sum_tree::Summary for TransformSummary {
 910    type Context = ();
 911
 912    fn add_summary(&mut self, other: &Self, _: &()) {
 913        self.input += &other.input;
 914        self.output += &other.output;
 915    }
 916}
 917
 918#[derive(Clone, Debug)]
 919struct Fold(Range<Anchor>);
 920
 921impl Default for Fold {
 922    fn default() -> Self {
 923        Self(Anchor::min()..Anchor::max())
 924    }
 925}
 926
 927impl sum_tree::Item for Fold {
 928    type Summary = FoldSummary;
 929
 930    fn summary(&self) -> Self::Summary {
 931        FoldSummary {
 932            start: self.0.start.clone(),
 933            end: self.0.end.clone(),
 934            min_start: self.0.start.clone(),
 935            max_end: self.0.end.clone(),
 936            count: 1,
 937        }
 938    }
 939}
 940
 941#[derive(Clone, Debug)]
 942struct FoldSummary {
 943    start: Anchor,
 944    end: Anchor,
 945    min_start: Anchor,
 946    max_end: Anchor,
 947    count: usize,
 948}
 949
 950impl Default for FoldSummary {
 951    fn default() -> Self {
 952        Self {
 953            start: Anchor::min(),
 954            end: Anchor::max(),
 955            min_start: Anchor::max(),
 956            max_end: Anchor::min(),
 957            count: 0,
 958        }
 959    }
 960}
 961
 962impl sum_tree::Summary for FoldSummary {
 963    type Context = MultiBufferSnapshot;
 964
 965    fn add_summary(&mut self, other: &Self, buffer: &MultiBufferSnapshot) {
 966        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 967            self.min_start = other.min_start.clone();
 968        }
 969        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 970            self.max_end = other.max_end.clone();
 971        }
 972
 973        #[cfg(debug_assertions)]
 974        {
 975            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 976            assert!(start_comparison <= Ordering::Equal);
 977            if start_comparison == Ordering::Equal {
 978                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 979            }
 980        }
 981
 982        self.start = other.start.clone();
 983        self.end = other.end.clone();
 984        self.count += other.count;
 985    }
 986}
 987
 988impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 989    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
 990        self.0.start = summary.start.clone();
 991        self.0.end = summary.end.clone();
 992    }
 993}
 994
 995impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 996    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
 997        self.0.cmp(&other.0, buffer).unwrap()
 998    }
 999}
1000
1001impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
1002    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1003        *self += summary.count;
1004    }
1005}
1006
1007pub struct FoldBufferRows<'a> {
1008    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
1009    input_buffer_rows: MultiBufferRows<'a>,
1010    fold_point: FoldPoint,
1011}
1012
1013impl<'a> Iterator for FoldBufferRows<'a> {
1014    type Item = Option<u32>;
1015
1016    fn next(&mut self) -> Option<Self::Item> {
1017        let mut traversed_fold = false;
1018        while self.fold_point > self.cursor.end(&()).0 {
1019            self.cursor.next(&());
1020            traversed_fold = true;
1021            if self.cursor.item().is_none() {
1022                break;
1023            }
1024        }
1025
1026        if self.cursor.item().is_some() {
1027            if traversed_fold {
1028                self.input_buffer_rows.seek(self.cursor.start().1.row);
1029                self.input_buffer_rows.next();
1030            }
1031            *self.fold_point.row_mut() += 1;
1032            self.input_buffer_rows.next()
1033        } else {
1034            None
1035        }
1036    }
1037}
1038
1039pub struct FoldChunks<'a> {
1040    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1041    buffer_chunks: MultiBufferChunks<'a>,
1042    buffer_chunk: Option<(usize, Chunk<'a>)>,
1043    buffer_offset: usize,
1044    output_offset: usize,
1045    max_output_offset: usize,
1046    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1047    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1048}
1049
1050impl<'a> Iterator for FoldChunks<'a> {
1051    type Item = Chunk<'a>;
1052
1053    fn next(&mut self) -> Option<Self::Item> {
1054        if self.output_offset >= self.max_output_offset {
1055            return None;
1056        }
1057
1058        let transform = if let Some(item) = self.transform_cursor.item() {
1059            item
1060        } else {
1061            return None;
1062        };
1063
1064        // If we're in a fold, then return the fold's display text and
1065        // advance the transform and buffer cursors to the end of the fold.
1066        if let Some(output_text) = transform.output_text {
1067            self.buffer_chunk.take();
1068            self.buffer_offset += transform.summary.input.bytes;
1069            self.buffer_chunks.seek(self.buffer_offset);
1070
1071            while self.buffer_offset >= self.transform_cursor.end(&()).1
1072                && self.transform_cursor.item().is_some()
1073            {
1074                self.transform_cursor.next(&());
1075            }
1076
1077            self.output_offset += output_text.len();
1078            return Some(Chunk {
1079                text: output_text,
1080                syntax_highlight_id: None,
1081                highlight_style: None,
1082                diagnostic_severity: None,
1083                is_unnecessary: false,
1084            });
1085        }
1086
1087        let mut next_highlight_endpoint = usize::MAX;
1088        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1089            if endpoint.offset <= self.buffer_offset {
1090                if endpoint.is_start {
1091                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1092                } else {
1093                    self.active_highlights.remove(&endpoint.tag);
1094                }
1095                self.highlight_endpoints.next();
1096            } else {
1097                next_highlight_endpoint = endpoint.offset;
1098                break;
1099            }
1100        }
1101
1102        // Retrieve a chunk from the current location in the buffer.
1103        if self.buffer_chunk.is_none() {
1104            let chunk_offset = self.buffer_chunks.offset();
1105            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1106        }
1107
1108        // Otherwise, take a chunk from the buffer's text.
1109        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1110            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1111            let transform_end = self.transform_cursor.end(&()).1;
1112            let chunk_end = buffer_chunk_end
1113                .min(transform_end)
1114                .min(next_highlight_endpoint);
1115
1116            chunk.text = &chunk.text
1117                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1118
1119            if !self.active_highlights.is_empty() {
1120                let mut highlight_style = HighlightStyle::default();
1121                for active_highlight in self.active_highlights.values() {
1122                    highlight_style.highlight(*active_highlight);
1123                }
1124                chunk.highlight_style = Some(highlight_style);
1125            }
1126
1127            if chunk_end == transform_end {
1128                self.transform_cursor.next(&());
1129            } else if chunk_end == buffer_chunk_end {
1130                self.buffer_chunk.take();
1131            }
1132
1133            self.buffer_offset = chunk_end;
1134            self.output_offset += chunk.text.len();
1135            return Some(chunk);
1136        }
1137
1138        None
1139    }
1140}
1141
1142#[derive(Copy, Clone, Eq, PartialEq)]
1143struct HighlightEndpoint {
1144    offset: usize,
1145    is_start: bool,
1146    tag: Option<TypeId>,
1147    style: HighlightStyle,
1148}
1149
1150impl PartialOrd for HighlightEndpoint {
1151    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1152        Some(self.cmp(other))
1153    }
1154}
1155
1156impl Ord for HighlightEndpoint {
1157    fn cmp(&self, other: &Self) -> Ordering {
1158        self.offset
1159            .cmp(&other.offset)
1160            .then_with(|| self.is_start.cmp(&other.is_start))
1161    }
1162}
1163
1164#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1165pub struct FoldOffset(pub usize);
1166
1167impl FoldOffset {
1168    pub fn to_point(&self, snapshot: &FoldSnapshot) -> FoldPoint {
1169        let mut cursor = snapshot
1170            .transforms
1171            .cursor::<(FoldOffset, TransformSummary)>();
1172        cursor.seek(self, Bias::Right, &());
1173        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1174            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1175        } else {
1176            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1177            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1178            buffer_point - cursor.start().1.input.lines
1179        };
1180        FoldPoint(cursor.start().1.output.lines + overshoot)
1181    }
1182}
1183
1184impl Sub for FoldOffset {
1185    type Output = Self;
1186
1187    fn sub(self, rhs: Self) -> Self::Output {
1188        Self(self.0 - rhs.0)
1189    }
1190}
1191
1192impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1193    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1194        self.0 += &summary.output.bytes;
1195    }
1196}
1197
1198impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1199    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1200        *self += &summary.input.lines;
1201    }
1202}
1203
1204impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1205    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1206        *self += &summary.input.bytes;
1207    }
1208}
1209
1210pub type FoldEdit = Edit<FoldOffset>;
1211
1212#[cfg(test)]
1213mod tests {
1214    use super::*;
1215    use crate::{MultiBuffer, ToPoint};
1216    use rand::prelude::*;
1217    use std::{cmp::Reverse, env, mem, sync::Arc};
1218    use sum_tree::TreeMap;
1219    use text::RandomCharIter;
1220    use util::test::sample_text;
1221    use Bias::{Left, Right};
1222
1223    #[gpui::test]
1224    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1225        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1226        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1227        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1228        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1229
1230        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1231        let (snapshot2, edits) = writer.fold(vec![
1232            Point::new(0, 2)..Point::new(2, 2),
1233            Point::new(2, 4)..Point::new(4, 1),
1234        ]);
1235        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1236        assert_eq!(
1237            edits,
1238            &[
1239                FoldEdit {
1240                    old: FoldOffset(2)..FoldOffset(16),
1241                    new: FoldOffset(2)..FoldOffset(5),
1242                },
1243                FoldEdit {
1244                    old: FoldOffset(18)..FoldOffset(29),
1245                    new: FoldOffset(7)..FoldOffset(10)
1246                },
1247            ]
1248        );
1249
1250        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1251            buffer.edit(
1252                vec![
1253                    Point::new(0, 0)..Point::new(0, 1),
1254                    Point::new(2, 3)..Point::new(2, 3),
1255                ],
1256                "123",
1257                cx,
1258            );
1259            buffer.snapshot(cx)
1260        });
1261        let (snapshot3, edits) =
1262            map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1263        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1264        assert_eq!(
1265            edits,
1266            &[
1267                FoldEdit {
1268                    old: FoldOffset(0)..FoldOffset(1),
1269                    new: FoldOffset(0)..FoldOffset(3),
1270                },
1271                FoldEdit {
1272                    old: FoldOffset(6)..FoldOffset(6),
1273                    new: FoldOffset(8)..FoldOffset(11),
1274                },
1275            ]
1276        );
1277
1278        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1279            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx);
1280            buffer.snapshot(cx)
1281        });
1282        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1283        assert_eq!(snapshot4.text(), "123a…c123456eee");
1284
1285        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1286        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), true);
1287        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1288        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1289    }
1290
1291    #[gpui::test]
1292    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1293        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1294        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1295        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1296
1297        {
1298            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1299
1300            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1301            writer.fold(vec![5..8]);
1302            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1303            assert_eq!(snapshot.text(), "abcde…ijkl");
1304
1305            // Create an fold adjacent to the start of the first fold.
1306            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1307            writer.fold(vec![0..1, 2..5]);
1308            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1309            assert_eq!(snapshot.text(), "…b…ijkl");
1310
1311            // Create an fold adjacent to the end of the first fold.
1312            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1313            writer.fold(vec![11..11, 8..10]);
1314            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1315            assert_eq!(snapshot.text(), "…b…kl");
1316        }
1317
1318        {
1319            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1320
1321            // Create two adjacent folds.
1322            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1323            writer.fold(vec![0..2, 2..5]);
1324            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1325            assert_eq!(snapshot.text(), "…fghijkl");
1326
1327            // Edit within one of the folds.
1328            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1329                buffer.edit(vec![0..1], "12345", cx);
1330                buffer.snapshot(cx)
1331            });
1332            let (snapshot, _) =
1333                map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1334            assert_eq!(snapshot.text(), "12345…fghijkl");
1335        }
1336    }
1337
1338    #[gpui::test]
1339    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1340        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1341        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1342        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1343        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1344        writer.fold(vec![
1345            Point::new(0, 2)..Point::new(2, 2),
1346            Point::new(0, 4)..Point::new(1, 0),
1347            Point::new(1, 2)..Point::new(3, 2),
1348            Point::new(3, 1)..Point::new(4, 1),
1349        ]);
1350        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1351        assert_eq!(snapshot.text(), "aa…eeeee");
1352    }
1353
1354    #[gpui::test]
1355    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1356        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1357        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1358        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1359        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1360
1361        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1362        writer.fold(vec![
1363            Point::new(0, 2)..Point::new(2, 2),
1364            Point::new(3, 1)..Point::new(4, 1),
1365        ]);
1366        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1367        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1368
1369        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1370            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx);
1371            buffer.snapshot(cx)
1372        });
1373        let (snapshot, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1374        assert_eq!(snapshot.text(), "aa…eeeee");
1375    }
1376
1377    #[gpui::test]
1378    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1379        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1380        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1381        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1382
1383        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1384        writer.fold(vec![
1385            Point::new(0, 2)..Point::new(2, 2),
1386            Point::new(0, 4)..Point::new(1, 0),
1387            Point::new(1, 2)..Point::new(3, 2),
1388            Point::new(3, 1)..Point::new(4, 1),
1389        ]);
1390        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1391        let fold_ranges = snapshot
1392            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1393            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1394            .collect::<Vec<_>>();
1395        assert_eq!(
1396            fold_ranges,
1397            vec![
1398                Point::new(0, 2)..Point::new(2, 2),
1399                Point::new(1, 2)..Point::new(3, 2)
1400            ]
1401        );
1402    }
1403
1404    #[gpui::test(iterations = 100)]
1405    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1406        let operations = env::var("OPERATIONS")
1407            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1408            .unwrap_or(10);
1409
1410        let len = rng.gen_range(0..10);
1411        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1412        let buffer = if rng.gen() {
1413            MultiBuffer::build_simple(&text, cx)
1414        } else {
1415            MultiBuffer::build_random(&mut rng, cx)
1416        };
1417        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1418        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1419
1420        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1421        let mut snapshot_edits = Vec::new();
1422
1423        let mut highlights = TreeMap::default();
1424        let highlight_count = rng.gen_range(0_usize..10);
1425        let mut highlight_ranges = (0..highlight_count)
1426            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1427            .collect::<Vec<_>>();
1428        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1429        log::info!("highlighting ranges {:?}", highlight_ranges);
1430        let highlight_ranges = highlight_ranges
1431            .into_iter()
1432            .map(|range| {
1433                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1434            })
1435            .collect::<Vec<_>>();
1436
1437        highlights.insert(
1438            Some(TypeId::of::<()>()),
1439            Arc::new((HighlightStyle::default(), highlight_ranges)),
1440        );
1441
1442        for _ in 0..operations {
1443            log::info!("text: {:?}", buffer_snapshot.text());
1444            let mut buffer_edits = Vec::new();
1445            match rng.gen_range(0..=100) {
1446                0..=59 => {
1447                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1448                }
1449                _ => buffer.update(cx, |buffer, cx| {
1450                    let subscription = buffer.subscribe();
1451                    let edit_count = rng.gen_range(1..=5);
1452                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1453                    buffer_snapshot = buffer.snapshot(cx);
1454                    let edits = subscription.consume().into_inner();
1455                    log::info!("editing {:?}", edits);
1456                    buffer_edits.extend(edits);
1457                }),
1458            };
1459
1460            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1461            snapshot_edits.push((snapshot.clone(), edits));
1462
1463            let mut expected_text: String = buffer_snapshot.text().to_string();
1464            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1465                expected_text.replace_range(fold_range.start..fold_range.end, "…");
1466            }
1467
1468            assert_eq!(snapshot.text(), expected_text);
1469            log::info!(
1470                "fold text {:?} ({} lines)",
1471                expected_text,
1472                expected_text.matches('\n').count() + 1
1473            );
1474
1475            let mut prev_row = 0;
1476            let mut expected_buffer_rows = Vec::new();
1477            for fold_range in map.merged_fold_ranges().into_iter() {
1478                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1479                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1480                expected_buffer_rows.extend(
1481                    buffer_snapshot
1482                        .buffer_rows(prev_row)
1483                        .take((1 + fold_start - prev_row) as usize),
1484                );
1485                prev_row = 1 + fold_end;
1486            }
1487            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1488
1489            assert_eq!(
1490                expected_buffer_rows.len(),
1491                expected_text.matches('\n').count() + 1,
1492                "wrong expected buffer rows {:?}. text: {:?}",
1493                expected_buffer_rows,
1494                expected_text
1495            );
1496
1497            for (output_row, line) in expected_text.lines().enumerate() {
1498                let line_len = snapshot.line_len(output_row as u32);
1499                assert_eq!(line_len, line.len() as u32);
1500            }
1501
1502            let longest_row = snapshot.longest_row();
1503            let longest_char_column = expected_text
1504                .split('\n')
1505                .nth(longest_row as usize)
1506                .unwrap()
1507                .chars()
1508                .count();
1509            let mut fold_point = FoldPoint::new(0, 0);
1510            let mut fold_offset = FoldOffset(0);
1511            let mut char_column = 0;
1512            for c in expected_text.chars() {
1513                let buffer_point = fold_point.to_buffer_point(&snapshot);
1514                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1515                assert_eq!(
1516                    snapshot.to_fold_point(buffer_point, Right),
1517                    fold_point,
1518                    "{:?} -> fold point",
1519                    buffer_point,
1520                );
1521                assert_eq!(
1522                    fold_point.to_buffer_offset(&snapshot),
1523                    buffer_offset,
1524                    "fold_point.to_buffer_offset({:?})",
1525                    fold_point,
1526                );
1527                assert_eq!(
1528                    fold_point.to_offset(&snapshot),
1529                    fold_offset,
1530                    "fold_point.to_offset({:?})",
1531                    fold_point,
1532                );
1533
1534                if c == '\n' {
1535                    *fold_point.row_mut() += 1;
1536                    *fold_point.column_mut() = 0;
1537                    char_column = 0;
1538                } else {
1539                    *fold_point.column_mut() += c.len_utf8() as u32;
1540                    char_column += 1;
1541                }
1542                fold_offset.0 += c.len_utf8();
1543                if char_column > longest_char_column {
1544                    panic!(
1545                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1546                        longest_row,
1547                        longest_char_column,
1548                        fold_point.row(),
1549                        char_column
1550                    );
1551                }
1552            }
1553
1554            for _ in 0..5 {
1555                let mut start = snapshot
1556                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1557                let mut end = snapshot
1558                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1559                if start > end {
1560                    mem::swap(&mut start, &mut end);
1561                }
1562
1563                let text = &expected_text[start.0..end.0];
1564                assert_eq!(
1565                    snapshot
1566                        .chunks(start..end, false, Some(&highlights))
1567                        .map(|c| c.text)
1568                        .collect::<String>(),
1569                    text,
1570                );
1571            }
1572
1573            let mut fold_row = 0;
1574            while fold_row < expected_buffer_rows.len() as u32 {
1575                fold_row = snapshot
1576                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1577                    .row();
1578                assert_eq!(
1579                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1580                    expected_buffer_rows[(fold_row as usize)..],
1581                    "wrong buffer rows starting at fold row {}",
1582                    fold_row,
1583                );
1584                fold_row += 1;
1585            }
1586
1587            for fold_range in map.merged_fold_ranges() {
1588                let fold_point =
1589                    snapshot.to_fold_point(fold_range.start.to_point(&buffer_snapshot), Right);
1590                assert!(snapshot.is_line_folded(fold_point.row()));
1591            }
1592
1593            for _ in 0..5 {
1594                let end =
1595                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1596                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1597                let expected_folds = map
1598                    .folds
1599                    .items(&buffer_snapshot)
1600                    .into_iter()
1601                    .filter(|fold| {
1602                        let start = buffer_snapshot.anchor_before(start);
1603                        let end = buffer_snapshot.anchor_after(end);
1604                        start.cmp(&fold.0.end, &buffer_snapshot).unwrap() == Ordering::Less
1605                            && end.cmp(&fold.0.start, &buffer_snapshot).unwrap()
1606                                == Ordering::Greater
1607                    })
1608                    .map(|fold| fold.0)
1609                    .collect::<Vec<_>>();
1610
1611                assert_eq!(
1612                    snapshot
1613                        .folds_in_range(start..end)
1614                        .cloned()
1615                        .collect::<Vec<_>>(),
1616                    expected_folds
1617                );
1618            }
1619
1620            let text = snapshot.text();
1621            for _ in 0..5 {
1622                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1623                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1624                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1625                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1626                let mut start =
1627                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1628                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1629                if start > end {
1630                    mem::swap(&mut start, &mut end);
1631                }
1632
1633                let lines = start..end;
1634                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1635                assert_eq!(
1636                    snapshot.text_summary_for_range(lines),
1637                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1638                )
1639            }
1640
1641            let mut text = initial_snapshot.text();
1642            for (snapshot, edits) in snapshot_edits.drain(..) {
1643                let new_text = snapshot.text();
1644                for edit in edits {
1645                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1646                    let new_bytes = edit.new.start.0..edit.new.end.0;
1647                    text.replace_range(old_bytes, &new_text[new_bytes]);
1648                }
1649
1650                assert_eq!(text, new_text);
1651                initial_snapshot = snapshot;
1652            }
1653        }
1654    }
1655
1656    #[gpui::test]
1657    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1658        let text = sample_text(6, 6, 'a') + "\n";
1659        let buffer = MultiBuffer::build_simple(&text, cx);
1660
1661        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1662        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1663
1664        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1665        writer.fold(vec![
1666            Point::new(0, 2)..Point::new(2, 2),
1667            Point::new(3, 1)..Point::new(4, 1),
1668        ]);
1669
1670        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1671        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1672        assert_eq!(
1673            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1674            [Some(0), Some(3), Some(5), Some(6)]
1675        );
1676        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1677    }
1678
1679    impl FoldMap {
1680        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1681            let buffer = self.buffer.lock().clone();
1682            let mut folds = self.folds.items(&buffer);
1683            // Ensure sorting doesn't change how folds get merged and displayed.
1684            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1685            let mut fold_ranges = folds
1686                .iter()
1687                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1688                .peekable();
1689
1690            let mut merged_ranges = Vec::new();
1691            while let Some(mut fold_range) = fold_ranges.next() {
1692                while let Some(next_range) = fold_ranges.peek() {
1693                    if fold_range.end >= next_range.start {
1694                        if next_range.end > fold_range.end {
1695                            fold_range.end = next_range.end;
1696                        }
1697                        fold_ranges.next();
1698                    } else {
1699                        break;
1700                    }
1701                }
1702                if fold_range.end > fold_range.start {
1703                    merged_ranges.push(fold_range);
1704                }
1705            }
1706            merged_ranges
1707        }
1708
1709        pub fn randomly_mutate(
1710            &mut self,
1711            rng: &mut impl Rng,
1712        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1713            let mut snapshot_edits = Vec::new();
1714            match rng.gen_range(0..=100) {
1715                0..=39 if !self.folds.is_empty() => {
1716                    let buffer = self.buffer.lock().clone();
1717                    let mut to_unfold = Vec::new();
1718                    for _ in 0..rng.gen_range(1..=3) {
1719                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1720                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1721                        to_unfold.push(start..end);
1722                    }
1723                    log::info!("unfolding {:?}", to_unfold);
1724                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1725                    snapshot_edits.push((snapshot, edits));
1726                    let (snapshot, edits) = writer.fold(to_unfold);
1727                    snapshot_edits.push((snapshot, edits));
1728                }
1729                _ => {
1730                    let buffer = self.buffer.lock().clone();
1731                    let mut to_fold = Vec::new();
1732                    for _ in 0..rng.gen_range(1..=2) {
1733                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1734                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1735                        to_fold.push(start..end);
1736                    }
1737                    log::info!("folding {:?}", to_fold);
1738                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1739                    snapshot_edits.push((snapshot, edits));
1740                    let (snapshot, edits) = writer.fold(to_fold);
1741                    snapshot_edits.push((snapshot, edits));
1742                }
1743            }
1744            snapshot_edits
1745        }
1746    }
1747}