1use super::TextHighlights;
   2use crate::{
   3    multi_buffer::MultiBufferRows, Anchor, AnchorRangeExt, MultiBufferChunks, MultiBufferSnapshot,
   4    ToOffset,
   5};
   6use collections::BTreeMap;
   7use gpui::{color::Color, fonts::HighlightStyle};
   8use language::{Chunk, Edit, Point, TextSummary};
   9use parking_lot::Mutex;
  10use std::{
  11    any::TypeId,
  12    cmp::{self, Ordering},
  13    iter::{self, Peekable},
  14    ops::{Range, Sub},
  15    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  16    vec,
  17};
  18use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  19
  20#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  21pub struct FoldPoint(pub Point);
  22
  23impl FoldPoint {
  24    pub fn new(row: u32, column: u32) -> Self {
  25        Self(Point::new(row, column))
  26    }
  27
  28    pub fn row(self) -> u32 {
  29        self.0.row
  30    }
  31
  32    pub fn 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.len;
  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.len;
  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            ellipses_color: self.0.ellipses_color,
 137        };
 138        (snapshot, edits)
 139    }
 140
 141    pub fn unfold<T: ToOffset>(
 142        &mut self,
 143        ranges: impl IntoIterator<Item = Range<T>>,
 144        inclusive: bool,
 145    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 146        let mut edits = Vec::new();
 147        let mut fold_ixs_to_delete = Vec::new();
 148        let buffer = self.0.buffer.lock().clone();
 149        for range in ranges.into_iter() {
 150            // Remove intersecting folds and add their ranges to edits that are passed to sync.
 151            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, inclusive);
 152            while let Some(fold) = folds_cursor.item() {
 153                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 154                if offset_range.end > offset_range.start {
 155                    edits.push(text::Edit {
 156                        old: offset_range.clone(),
 157                        new: offset_range,
 158                    });
 159                }
 160                fold_ixs_to_delete.push(*folds_cursor.start());
 161                folds_cursor.next(&buffer);
 162            }
 163        }
 164
 165        fold_ixs_to_delete.sort_unstable();
 166        fold_ixs_to_delete.dedup();
 167
 168        self.0.folds = {
 169            let mut cursor = self.0.folds.cursor::<usize>();
 170            let mut folds = SumTree::new();
 171            for fold_ix in fold_ixs_to_delete {
 172                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 173                cursor.next(&buffer);
 174            }
 175            folds.push_tree(cursor.suffix(&buffer), &buffer);
 176            folds
 177        };
 178
 179        consolidate_buffer_edits(&mut edits);
 180        let edits = self.0.sync(buffer.clone(), edits);
 181        let snapshot = FoldSnapshot {
 182            transforms: self.0.transforms.lock().clone(),
 183            folds: self.0.folds.clone(),
 184            buffer_snapshot: buffer,
 185            version: self.0.version.load(SeqCst),
 186            ellipses_color: self.0.ellipses_color,
 187        };
 188        (snapshot, edits)
 189    }
 190}
 191
 192pub struct FoldMap {
 193    buffer: Mutex<MultiBufferSnapshot>,
 194    transforms: Mutex<SumTree<Transform>>,
 195    folds: SumTree<Fold>,
 196    version: AtomicUsize,
 197    ellipses_color: Option<Color>,
 198}
 199
 200impl FoldMap {
 201    pub fn new(buffer: MultiBufferSnapshot) -> (Self, FoldSnapshot) {
 202        let this = Self {
 203            buffer: Mutex::new(buffer.clone()),
 204            folds: Default::default(),
 205            transforms: Mutex::new(SumTree::from_item(
 206                Transform {
 207                    summary: TransformSummary {
 208                        input: buffer.text_summary(),
 209                        output: buffer.text_summary(),
 210                    },
 211                    output_text: None,
 212                },
 213                &(),
 214            )),
 215            ellipses_color: None,
 216            version: Default::default(),
 217        };
 218
 219        let snapshot = FoldSnapshot {
 220            transforms: this.transforms.lock().clone(),
 221            folds: this.folds.clone(),
 222            buffer_snapshot: this.buffer.lock().clone(),
 223            version: this.version.load(SeqCst),
 224            ellipses_color: None,
 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            ellipses_color: self.ellipses_color,
 242        };
 243        (snapshot, edits)
 244    }
 245
 246    pub fn write(
 247        &mut self,
 248        buffer: MultiBufferSnapshot,
 249        edits: Vec<Edit<usize>>,
 250    ) -> (FoldMapWriter, FoldSnapshot, Vec<FoldEdit>) {
 251        let (snapshot, edits) = self.read(buffer, edits);
 252        (FoldMapWriter(self), snapshot, edits)
 253    }
 254
 255    pub fn set_ellipses_color(&mut self, color: Color) -> bool {
 256        if self.ellipses_color != Some(color) {
 257            self.ellipses_color = Some(color);
 258            true
 259        } else {
 260            false
 261        }
 262    }
 263
 264    fn check_invariants(&self) {
 265        if cfg!(test) {
 266            assert_eq!(
 267                self.transforms.lock().summary().input.len,
 268                self.buffer.lock().len(),
 269                "transform tree does not match buffer's length"
 270            );
 271
 272            let mut folds = self.folds.iter().peekable();
 273            while let Some(fold) = folds.next() {
 274                if let Some(next_fold) = folds.peek() {
 275                    let comparison = fold.0.cmp(&next_fold.0, &self.buffer.lock());
 276                    assert!(comparison.is_le());
 277                }
 278            }
 279        }
 280    }
 281
 282    fn sync(
 283        &self,
 284        new_buffer: MultiBufferSnapshot,
 285        buffer_edits: Vec<text::Edit<usize>>,
 286    ) -> Vec<FoldEdit> {
 287        if buffer_edits.is_empty() {
 288            let mut buffer = self.buffer.lock();
 289            if buffer.edit_count() != new_buffer.edit_count()
 290                || buffer.parse_count() != new_buffer.parse_count()
 291                || buffer.diagnostics_update_count() != new_buffer.diagnostics_update_count()
 292                || buffer.git_diff_update_count() != new_buffer.git_diff_update_count()
 293                || buffer.trailing_excerpt_update_count()
 294                    != new_buffer.trailing_excerpt_update_count()
 295            {
 296                self.version.fetch_add(1, SeqCst);
 297            }
 298            *buffer = new_buffer;
 299            Vec::new()
 300        } else {
 301            let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 302
 303            let mut new_transforms = SumTree::new();
 304            let mut transforms = self.transforms.lock();
 305            let mut cursor = transforms.cursor::<usize>();
 306            cursor.seek(&0, Bias::Right, &());
 307
 308            while let Some(mut edit) = buffer_edits_iter.next() {
 309                new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 310                edit.new.start -= edit.old.start - cursor.start();
 311                edit.old.start = *cursor.start();
 312
 313                cursor.seek(&edit.old.end, Bias::Right, &());
 314                cursor.next(&());
 315
 316                let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 317                loop {
 318                    edit.old.end = *cursor.start();
 319
 320                    if let Some(next_edit) = buffer_edits_iter.peek() {
 321                        if next_edit.old.start > edit.old.end {
 322                            break;
 323                        }
 324
 325                        let next_edit = buffer_edits_iter.next().unwrap();
 326                        delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 327
 328                        if next_edit.old.end >= edit.old.end {
 329                            edit.old.end = next_edit.old.end;
 330                            cursor.seek(&edit.old.end, Bias::Right, &());
 331                            cursor.next(&());
 332                        }
 333                    } else {
 334                        break;
 335                    }
 336                }
 337
 338                edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 339
 340                let anchor = new_buffer.anchor_before(edit.new.start);
 341                let mut folds_cursor = self.folds.cursor::<Fold>();
 342                folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &new_buffer);
 343
 344                let mut folds = iter::from_fn({
 345                    let buffer = &new_buffer;
 346                    move || {
 347                        let item = folds_cursor
 348                            .item()
 349                            .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 350                        folds_cursor.next(buffer);
 351                        item
 352                    }
 353                })
 354                .peekable();
 355
 356                while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 357                    let mut fold = folds.next().unwrap();
 358                    let sum = new_transforms.summary();
 359
 360                    assert!(fold.start >= sum.input.len);
 361
 362                    while folds
 363                        .peek()
 364                        .map_or(false, |next_fold| next_fold.start <= fold.end)
 365                    {
 366                        let next_fold = folds.next().unwrap();
 367                        if next_fold.end > fold.end {
 368                            fold.end = next_fold.end;
 369                        }
 370                    }
 371
 372                    if fold.start > sum.input.len {
 373                        let text_summary = new_buffer
 374                            .text_summary_for_range::<TextSummary, _>(sum.input.len..fold.start);
 375                        new_transforms.push(
 376                            Transform {
 377                                summary: TransformSummary {
 378                                    output: text_summary.clone(),
 379                                    input: text_summary,
 380                                },
 381                                output_text: None,
 382                            },
 383                            &(),
 384                        );
 385                    }
 386
 387                    if fold.end > fold.start {
 388                        let output_text = "⋯";
 389                        new_transforms.push(
 390                            Transform {
 391                                summary: TransformSummary {
 392                                    output: TextSummary::from(output_text),
 393                                    input: new_buffer.text_summary_for_range(fold.start..fold.end),
 394                                },
 395                                output_text: Some(output_text),
 396                            },
 397                            &(),
 398                        );
 399                    }
 400                }
 401
 402                let sum = new_transforms.summary();
 403                if sum.input.len < edit.new.end {
 404                    let text_summary = new_buffer
 405                        .text_summary_for_range::<TextSummary, _>(sum.input.len..edit.new.end);
 406                    new_transforms.push(
 407                        Transform {
 408                            summary: TransformSummary {
 409                                output: text_summary.clone(),
 410                                input: text_summary,
 411                            },
 412                            output_text: None,
 413                        },
 414                        &(),
 415                    );
 416                }
 417            }
 418
 419            new_transforms.push_tree(cursor.suffix(&()), &());
 420            if new_transforms.is_empty() {
 421                let text_summary = new_buffer.text_summary();
 422                new_transforms.push(
 423                    Transform {
 424                        summary: TransformSummary {
 425                            output: text_summary.clone(),
 426                            input: text_summary,
 427                        },
 428                        output_text: None,
 429                    },
 430                    &(),
 431                );
 432            }
 433
 434            drop(cursor);
 435
 436            let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 437            {
 438                let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 439                let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 440
 441                for mut edit in buffer_edits {
 442                    old_transforms.seek(&edit.old.start, Bias::Left, &());
 443                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 444                        edit.old.start = old_transforms.start().0;
 445                    }
 446                    let old_start =
 447                        old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 448
 449                    old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 450                    if old_transforms.item().map_or(false, |t| t.is_fold()) {
 451                        old_transforms.next(&());
 452                        edit.old.end = old_transforms.start().0;
 453                    }
 454                    let old_end =
 455                        old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 456
 457                    new_transforms.seek(&edit.new.start, Bias::Left, &());
 458                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 459                        edit.new.start = new_transforms.start().0;
 460                    }
 461                    let new_start =
 462                        new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 463
 464                    new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 465                    if new_transforms.item().map_or(false, |t| t.is_fold()) {
 466                        new_transforms.next(&());
 467                        edit.new.end = new_transforms.start().0;
 468                    }
 469                    let new_end =
 470                        new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 471
 472                    fold_edits.push(FoldEdit {
 473                        old: FoldOffset(old_start)..FoldOffset(old_end),
 474                        new: FoldOffset(new_start)..FoldOffset(new_end),
 475                    });
 476                }
 477
 478                consolidate_fold_edits(&mut fold_edits);
 479            }
 480
 481            *transforms = new_transforms;
 482            *self.buffer.lock() = new_buffer;
 483            self.version.fetch_add(1, SeqCst);
 484            fold_edits
 485        }
 486    }
 487}
 488
 489#[derive(Clone)]
 490pub struct FoldSnapshot {
 491    transforms: SumTree<Transform>,
 492    folds: SumTree<Fold>,
 493    buffer_snapshot: MultiBufferSnapshot,
 494    pub version: usize,
 495    pub ellipses_color: Option<Color>,
 496}
 497
 498impl FoldSnapshot {
 499    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 500        &self.buffer_snapshot
 501    }
 502
 503    #[cfg(test)]
 504    pub fn text(&self) -> String {
 505        self.chunks(FoldOffset(0)..self.len(), false, None)
 506            .map(|c| c.text)
 507            .collect()
 508    }
 509
 510    #[cfg(test)]
 511    pub fn fold_count(&self) -> usize {
 512        self.folds.items(&self.buffer_snapshot).len()
 513    }
 514
 515    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 516        let mut summary = TextSummary::default();
 517
 518        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 519        cursor.seek(&range.start, Bias::Right, &());
 520        if let Some(transform) = cursor.item() {
 521            let start_in_transform = range.start.0 - cursor.start().0 .0;
 522            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 523            if let Some(output_text) = transform.output_text {
 524                summary = TextSummary::from(
 525                    &output_text
 526                        [start_in_transform.column as usize..end_in_transform.column as usize],
 527                );
 528            } else {
 529                let buffer_start = cursor.start().1 + start_in_transform;
 530                let buffer_end = cursor.start().1 + end_in_transform;
 531                summary = self
 532                    .buffer_snapshot
 533                    .text_summary_for_range(buffer_start..buffer_end);
 534            }
 535        }
 536
 537        if range.end > cursor.end(&()).0 {
 538            cursor.next(&());
 539            summary += &cursor
 540                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 541                .output;
 542            if let Some(transform) = cursor.item() {
 543                let end_in_transform = range.end.0 - cursor.start().0 .0;
 544                if let Some(output_text) = transform.output_text {
 545                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 546                } else {
 547                    let buffer_start = cursor.start().1;
 548                    let buffer_end = cursor.start().1 + end_in_transform;
 549                    summary += self
 550                        .buffer_snapshot
 551                        .text_summary_for_range::<TextSummary, _>(buffer_start..buffer_end);
 552                }
 553            }
 554        }
 555
 556        summary
 557    }
 558
 559    pub fn to_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
 560        let mut cursor = self.transforms.cursor::<(Point, FoldPoint)>();
 561        cursor.seek(&point, Bias::Right, &());
 562        if cursor.item().map_or(false, |t| t.is_fold()) {
 563            if bias == Bias::Left || point == cursor.start().0 {
 564                cursor.start().1
 565            } else {
 566                cursor.end(&()).1
 567            }
 568        } else {
 569            let overshoot = point - cursor.start().0;
 570            FoldPoint(cmp::min(
 571                cursor.start().1 .0 + overshoot,
 572                cursor.end(&()).1 .0,
 573            ))
 574        }
 575    }
 576
 577    pub fn len(&self) -> FoldOffset {
 578        FoldOffset(self.transforms.summary().output.len)
 579    }
 580
 581    pub fn line_len(&self, row: u32) -> u32 {
 582        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 583        let line_end = if row >= self.max_point().row() {
 584            self.len().0
 585        } else {
 586            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 587        };
 588        (line_end - line_start) as u32
 589    }
 590
 591    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
 592        if start_row > self.transforms.summary().output.lines.row {
 593            panic!("invalid display row {}", start_row);
 594        }
 595
 596        let fold_point = FoldPoint::new(start_row, 0);
 597        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 598        cursor.seek(&fold_point, Bias::Left, &());
 599
 600        let overshoot = fold_point.0 - cursor.start().0 .0;
 601        let buffer_point = cursor.start().1 + overshoot;
 602        let input_buffer_rows = self.buffer_snapshot.buffer_rows(buffer_point.row);
 603
 604        FoldBufferRows {
 605            fold_point,
 606            input_buffer_rows,
 607            cursor,
 608        }
 609    }
 610
 611    pub fn max_point(&self) -> FoldPoint {
 612        FoldPoint(self.transforms.summary().output.lines)
 613    }
 614
 615    #[cfg(test)]
 616    pub fn longest_row(&self) -> u32 {
 617        self.transforms.summary().output.longest_row
 618    }
 619
 620    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Range<Anchor>>
 621    where
 622        T: ToOffset,
 623    {
 624        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 625        iter::from_fn(move || {
 626            let item = folds.item().map(|f| &f.0);
 627            folds.next(&self.buffer_snapshot);
 628            item
 629        })
 630    }
 631
 632    pub fn intersects_fold<T>(&self, offset: T) -> bool
 633    where
 634        T: ToOffset,
 635    {
 636        let offset = offset.to_offset(&self.buffer_snapshot);
 637        let mut cursor = self.transforms.cursor::<usize>();
 638        cursor.seek(&offset, Bias::Right, &());
 639        cursor.item().map_or(false, |t| t.output_text.is_some())
 640    }
 641
 642    pub fn is_line_folded(&self, output_row: u32) -> bool {
 643        let mut cursor = self.transforms.cursor::<FoldPoint>();
 644        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 645        while let Some(transform) = cursor.item() {
 646            if transform.output_text.is_some() {
 647                return true;
 648            }
 649            if cursor.end(&()).row() == output_row {
 650                cursor.next(&())
 651            } else {
 652                break;
 653            }
 654        }
 655        false
 656    }
 657
 658    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 659        let start = start.to_offset(self);
 660        self.chunks(start..self.len(), false, None)
 661            .flat_map(|chunk| chunk.text.chars())
 662    }
 663
 664    pub fn chunks<'a>(
 665        &'a self,
 666        range: Range<FoldOffset>,
 667        language_aware: bool,
 668        text_highlights: Option<&'a TextHighlights>,
 669    ) -> FoldChunks<'a> {
 670        let mut highlight_endpoints = Vec::new();
 671        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 672
 673        let buffer_end = {
 674            transform_cursor.seek(&range.end, Bias::Right, &());
 675            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 676            transform_cursor.start().1 + overshoot
 677        };
 678
 679        let buffer_start = {
 680            transform_cursor.seek(&range.start, Bias::Right, &());
 681            let overshoot = range.start.0 - transform_cursor.start().0 .0;
 682            transform_cursor.start().1 + overshoot
 683        };
 684
 685        if let Some(text_highlights) = text_highlights {
 686            if !text_highlights.is_empty() {
 687                while transform_cursor.start().0 < range.end {
 688                    if !transform_cursor.item().unwrap().is_fold() {
 689                        let transform_start = self
 690                            .buffer_snapshot
 691                            .anchor_after(cmp::max(buffer_start, transform_cursor.start().1));
 692
 693                        let transform_end = {
 694                            let overshoot = range.end.0 - transform_cursor.start().0 .0;
 695                            self.buffer_snapshot.anchor_before(cmp::min(
 696                                transform_cursor.end(&()).1,
 697                                transform_cursor.start().1 + overshoot,
 698                            ))
 699                        };
 700
 701                        for (tag, highlights) in text_highlights.iter() {
 702                            let style = highlights.0;
 703                            let ranges = &highlights.1;
 704
 705                            let start_ix = match ranges.binary_search_by(|probe| {
 706                                let cmp = probe.end.cmp(&transform_start, self.buffer_snapshot());
 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                                    .is_ge()
 720                                {
 721                                    break;
 722                                }
 723
 724                                highlight_endpoints.push(HighlightEndpoint {
 725                                    offset: range.start.to_offset(&self.buffer_snapshot),
 726                                    is_start: true,
 727                                    tag: *tag,
 728                                    style,
 729                                });
 730                                highlight_endpoints.push(HighlightEndpoint {
 731                                    offset: range.end.to_offset(&self.buffer_snapshot),
 732                                    is_start: false,
 733                                    tag: *tag,
 734                                    style,
 735                                });
 736                            }
 737                        }
 738                    }
 739
 740                    transform_cursor.next(&());
 741                }
 742                highlight_endpoints.sort();
 743                transform_cursor.seek(&range.start, Bias::Right, &());
 744            }
 745        }
 746
 747        FoldChunks {
 748            transform_cursor,
 749            buffer_chunks: self
 750                .buffer_snapshot
 751                .chunks(buffer_start..buffer_end, language_aware),
 752            buffer_chunk: None,
 753            buffer_offset: buffer_start,
 754            output_offset: range.start.0,
 755            max_output_offset: range.end.0,
 756            highlight_endpoints: highlight_endpoints.into_iter().peekable(),
 757            active_highlights: Default::default(),
 758            ellipses_color: self.ellipses_color,
 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.len)
 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);
 825        let end_cmp = end.cmp(&summary.min_start, buffer);
 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) == Ordering::Less {
 967            self.min_start = other.min_start.clone();
 968        }
 969        if other.max_end.cmp(&self.max_end, buffer) == 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);
 976            assert!(start_comparison <= Ordering::Equal);
 977            if start_comparison == Ordering::Equal {
 978                assert!(self.end.cmp(&other.end, buffer) >= 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)
 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
1007#[derive(Clone)]
1008pub struct FoldBufferRows<'a> {
1009    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
1010    input_buffer_rows: MultiBufferRows<'a>,
1011    fold_point: FoldPoint,
1012}
1013
1014impl<'a> Iterator for FoldBufferRows<'a> {
1015    type Item = Option<u32>;
1016
1017    fn next(&mut self) -> Option<Self::Item> {
1018        let mut traversed_fold = false;
1019        while self.fold_point > self.cursor.end(&()).0 {
1020            self.cursor.next(&());
1021            traversed_fold = true;
1022            if self.cursor.item().is_none() {
1023                break;
1024            }
1025        }
1026
1027        if self.cursor.item().is_some() {
1028            if traversed_fold {
1029                self.input_buffer_rows.seek(self.cursor.start().1.row);
1030                self.input_buffer_rows.next();
1031            }
1032            *self.fold_point.row_mut() += 1;
1033            self.input_buffer_rows.next()
1034        } else {
1035            None
1036        }
1037    }
1038}
1039
1040pub struct FoldChunks<'a> {
1041    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1042    buffer_chunks: MultiBufferChunks<'a>,
1043    buffer_chunk: Option<(usize, Chunk<'a>)>,
1044    buffer_offset: usize,
1045    output_offset: usize,
1046    max_output_offset: usize,
1047    highlight_endpoints: Peekable<vec::IntoIter<HighlightEndpoint>>,
1048    active_highlights: BTreeMap<Option<TypeId>, HighlightStyle>,
1049    ellipses_color: Option<Color>,
1050}
1051
1052impl<'a> Iterator for FoldChunks<'a> {
1053    type Item = Chunk<'a>;
1054
1055    fn next(&mut self) -> Option<Self::Item> {
1056        if self.output_offset >= self.max_output_offset {
1057            return None;
1058        }
1059
1060        let transform = self.transform_cursor.item()?;
1061
1062        // If we're in a fold, then return the fold's display text and
1063        // advance the transform and buffer cursors to the end of the fold.
1064        if let Some(output_text) = transform.output_text {
1065            self.buffer_chunk.take();
1066            self.buffer_offset += transform.summary.input.len;
1067            self.buffer_chunks.seek(self.buffer_offset);
1068
1069            while self.buffer_offset >= self.transform_cursor.end(&()).1
1070                && self.transform_cursor.item().is_some()
1071            {
1072                self.transform_cursor.next(&());
1073            }
1074
1075            self.output_offset += output_text.len();
1076            return Some(Chunk {
1077                text: output_text,
1078                syntax_highlight_id: None,
1079                highlight_style: self.ellipses_color.map(|color| HighlightStyle {
1080                    color: Some(color),
1081                    ..Default::default()
1082                }),
1083                diagnostic_severity: None,
1084                is_unnecessary: false,
1085            });
1086        }
1087
1088        let mut next_highlight_endpoint = usize::MAX;
1089        while let Some(endpoint) = self.highlight_endpoints.peek().copied() {
1090            if endpoint.offset <= self.buffer_offset {
1091                if endpoint.is_start {
1092                    self.active_highlights.insert(endpoint.tag, endpoint.style);
1093                } else {
1094                    self.active_highlights.remove(&endpoint.tag);
1095                }
1096                self.highlight_endpoints.next();
1097            } else {
1098                next_highlight_endpoint = endpoint.offset;
1099                break;
1100            }
1101        }
1102
1103        // Retrieve a chunk from the current location in the buffer.
1104        if self.buffer_chunk.is_none() {
1105            let chunk_offset = self.buffer_chunks.offset();
1106            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1107        }
1108
1109        // Otherwise, take a chunk from the buffer's text.
1110        if let Some((buffer_chunk_start, mut chunk)) = self.buffer_chunk {
1111            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1112            let transform_end = self.transform_cursor.end(&()).1;
1113            let chunk_end = buffer_chunk_end
1114                .min(transform_end)
1115                .min(next_highlight_endpoint);
1116
1117            chunk.text = &chunk.text
1118                [self.buffer_offset - buffer_chunk_start..chunk_end - buffer_chunk_start];
1119
1120            if !self.active_highlights.is_empty() {
1121                let mut highlight_style = HighlightStyle::default();
1122                for active_highlight in self.active_highlights.values() {
1123                    highlight_style.highlight(*active_highlight);
1124                }
1125                chunk.highlight_style = Some(highlight_style);
1126            }
1127
1128            if chunk_end == transform_end {
1129                self.transform_cursor.next(&());
1130            } else if chunk_end == buffer_chunk_end {
1131                self.buffer_chunk.take();
1132            }
1133
1134            self.buffer_offset = chunk_end;
1135            self.output_offset += chunk.text.len();
1136            return Some(chunk);
1137        }
1138
1139        None
1140    }
1141}
1142
1143#[derive(Copy, Clone, Eq, PartialEq)]
1144struct HighlightEndpoint {
1145    offset: usize,
1146    is_start: bool,
1147    tag: Option<TypeId>,
1148    style: HighlightStyle,
1149}
1150
1151impl PartialOrd for HighlightEndpoint {
1152    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1153        Some(self.cmp(other))
1154    }
1155}
1156
1157impl Ord for HighlightEndpoint {
1158    fn cmp(&self, other: &Self) -> Ordering {
1159        self.offset
1160            .cmp(&other.offset)
1161            .then_with(|| other.is_start.cmp(&self.is_start))
1162    }
1163}
1164
1165#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1166pub struct FoldOffset(pub usize);
1167
1168impl FoldOffset {
1169    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1170        let mut cursor = snapshot
1171            .transforms
1172            .cursor::<(FoldOffset, TransformSummary)>();
1173        cursor.seek(&self, Bias::Right, &());
1174        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1175            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1176        } else {
1177            let buffer_offset = cursor.start().1.input.len + self.0 - cursor.start().0 .0;
1178            let buffer_point = snapshot.buffer_snapshot.offset_to_point(buffer_offset);
1179            buffer_point - cursor.start().1.input.lines
1180        };
1181        FoldPoint(cursor.start().1.output.lines + overshoot)
1182    }
1183}
1184
1185impl Sub for FoldOffset {
1186    type Output = Self;
1187
1188    fn sub(self, rhs: Self) -> Self::Output {
1189        Self(self.0 - rhs.0)
1190    }
1191}
1192
1193impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1194    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1195        self.0 += &summary.output.len;
1196    }
1197}
1198
1199impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1200    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1201        *self += &summary.input.lines;
1202    }
1203}
1204
1205impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1206    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1207        *self += &summary.input.len;
1208    }
1209}
1210
1211pub type FoldEdit = Edit<FoldOffset>;
1212
1213#[cfg(test)]
1214mod tests {
1215    use super::*;
1216    use crate::{MultiBuffer, ToPoint};
1217    use rand::prelude::*;
1218    use settings::Settings;
1219    use std::{cmp::Reverse, env, mem, sync::Arc};
1220    use sum_tree::TreeMap;
1221    use util::test::sample_text;
1222    use util::RandomCharIter;
1223    use Bias::{Left, Right};
1224
1225    #[gpui::test]
1226    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1227        cx.set_global(Settings::test(cx));
1228        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1229        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1230        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1231        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1232
1233        let (mut writer, _, _) = map.write(buffer_snapshot, vec![]);
1234        let (snapshot2, edits) = writer.fold(vec![
1235            Point::new(0, 2)..Point::new(2, 2),
1236            Point::new(2, 4)..Point::new(4, 1),
1237        ]);
1238        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1239        assert_eq!(
1240            edits,
1241            &[
1242                FoldEdit {
1243                    old: FoldOffset(2)..FoldOffset(16),
1244                    new: FoldOffset(2)..FoldOffset(5),
1245                },
1246                FoldEdit {
1247                    old: FoldOffset(18)..FoldOffset(29),
1248                    new: FoldOffset(7)..FoldOffset(10)
1249                },
1250            ]
1251        );
1252
1253        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1254            buffer.edit(
1255                vec![
1256                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1257                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1258                ],
1259                None,
1260                cx,
1261            );
1262            buffer.snapshot(cx)
1263        });
1264        let (snapshot3, edits) = map.read(buffer_snapshot, subscription.consume().into_inner());
1265        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1266        assert_eq!(
1267            edits,
1268            &[
1269                FoldEdit {
1270                    old: FoldOffset(0)..FoldOffset(1),
1271                    new: FoldOffset(0)..FoldOffset(3),
1272                },
1273                FoldEdit {
1274                    old: FoldOffset(6)..FoldOffset(6),
1275                    new: FoldOffset(8)..FoldOffset(11),
1276                },
1277            ]
1278        );
1279
1280        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1281            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1282            buffer.snapshot(cx)
1283        });
1284        let (snapshot4, _) = map.read(buffer_snapshot.clone(), subscription.consume().into_inner());
1285        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1286
1287        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1288        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1289        let (snapshot5, _) = map.read(buffer_snapshot.clone(), vec![]);
1290        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1291
1292        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1293        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1294        let (snapshot6, _) = map.read(buffer_snapshot, vec![]);
1295        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1296    }
1297
1298    #[gpui::test]
1299    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1300        cx.set_global(Settings::test(cx));
1301        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1302        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1303        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1304
1305        {
1306            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1307
1308            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1309            writer.fold(vec![5..8]);
1310            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1311            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1312
1313            // Create an fold adjacent to the start of the first fold.
1314            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1315            writer.fold(vec![0..1, 2..5]);
1316            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1317            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1318
1319            // Create an fold adjacent to the end of the first fold.
1320            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1321            writer.fold(vec![11..11, 8..10]);
1322            let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1323            assert_eq!(snapshot.text(), "⋯b⋯kl");
1324        }
1325
1326        {
1327            let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1328
1329            // Create two adjacent folds.
1330            let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1331            writer.fold(vec![0..2, 2..5]);
1332            let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1333            assert_eq!(snapshot.text(), "⋯fghijkl");
1334
1335            // Edit within one of the folds.
1336            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1337                buffer.edit([(0..1, "12345")], None, cx);
1338                buffer.snapshot(cx)
1339            });
1340            let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1341            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1342        }
1343    }
1344
1345    #[gpui::test]
1346    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1347        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1348        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1349        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1350        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1351        writer.fold(vec![
1352            Point::new(0, 2)..Point::new(2, 2),
1353            Point::new(0, 4)..Point::new(1, 0),
1354            Point::new(1, 2)..Point::new(3, 2),
1355            Point::new(3, 1)..Point::new(4, 1),
1356        ]);
1357        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1358        assert_eq!(snapshot.text(), "aa⋯eeeee");
1359    }
1360
1361    #[gpui::test]
1362    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1363        cx.set_global(Settings::test(cx));
1364        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1365        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1366        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1367        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1368
1369        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1370        writer.fold(vec![
1371            Point::new(0, 2)..Point::new(2, 2),
1372            Point::new(3, 1)..Point::new(4, 1),
1373        ]);
1374        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1375        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1376
1377        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1378            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1379            buffer.snapshot(cx)
1380        });
1381        let (snapshot, _) = map.read(buffer_snapshot, subscription.consume().into_inner());
1382        assert_eq!(snapshot.text(), "aa⋯eeeee");
1383    }
1384
1385    #[gpui::test]
1386    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1387        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1388        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1389        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1390
1391        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1392        writer.fold(vec![
1393            Point::new(0, 2)..Point::new(2, 2),
1394            Point::new(0, 4)..Point::new(1, 0),
1395            Point::new(1, 2)..Point::new(3, 2),
1396            Point::new(3, 1)..Point::new(4, 1),
1397        ]);
1398        let (snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1399        let fold_ranges = snapshot
1400            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1401            .map(|fold| fold.start.to_point(&buffer_snapshot)..fold.end.to_point(&buffer_snapshot))
1402            .collect::<Vec<_>>();
1403        assert_eq!(
1404            fold_ranges,
1405            vec![
1406                Point::new(0, 2)..Point::new(2, 2),
1407                Point::new(1, 2)..Point::new(3, 2)
1408            ]
1409        );
1410    }
1411
1412    #[gpui::test(iterations = 100)]
1413    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1414        cx.set_global(Settings::test(cx));
1415        let operations = env::var("OPERATIONS")
1416            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1417            .unwrap_or(10);
1418
1419        let len = rng.gen_range(0..10);
1420        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1421        let buffer = if rng.gen() {
1422            MultiBuffer::build_simple(&text, cx)
1423        } else {
1424            MultiBuffer::build_random(&mut rng, cx)
1425        };
1426        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1427        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1428
1429        let (mut initial_snapshot, _) = map.read(buffer_snapshot.clone(), vec![]);
1430        let mut snapshot_edits = Vec::new();
1431
1432        let mut highlights = TreeMap::default();
1433        let highlight_count = rng.gen_range(0_usize..10);
1434        let mut highlight_ranges = (0..highlight_count)
1435            .map(|_| buffer_snapshot.random_byte_range(0, &mut rng))
1436            .collect::<Vec<_>>();
1437        highlight_ranges.sort_by_key(|range| (range.start, Reverse(range.end)));
1438        log::info!("highlighting ranges {:?}", highlight_ranges);
1439        let highlight_ranges = highlight_ranges
1440            .into_iter()
1441            .map(|range| {
1442                buffer_snapshot.anchor_before(range.start)..buffer_snapshot.anchor_after(range.end)
1443            })
1444            .collect::<Vec<_>>();
1445
1446        highlights.insert(
1447            Some(TypeId::of::<()>()),
1448            Arc::new((HighlightStyle::default(), highlight_ranges)),
1449        );
1450
1451        for _ in 0..operations {
1452            log::info!("text: {:?}", buffer_snapshot.text());
1453            let mut buffer_edits = Vec::new();
1454            match rng.gen_range(0..=100) {
1455                0..=59 => {
1456                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1457                }
1458                _ => buffer.update(cx, |buffer, cx| {
1459                    let subscription = buffer.subscribe();
1460                    let edit_count = rng.gen_range(1..=5);
1461                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1462                    buffer_snapshot = buffer.snapshot(cx);
1463                    let edits = subscription.consume().into_inner();
1464                    log::info!("editing {:?}", edits);
1465                    buffer_edits.extend(edits);
1466                }),
1467            };
1468
1469            let (snapshot, edits) = map.read(buffer_snapshot.clone(), buffer_edits);
1470            snapshot_edits.push((snapshot.clone(), edits));
1471
1472            let mut expected_text: String = buffer_snapshot.text().to_string();
1473            for fold_range in map.merged_fold_ranges().into_iter().rev() {
1474                expected_text.replace_range(fold_range.start..fold_range.end, "⋯");
1475            }
1476
1477            assert_eq!(snapshot.text(), expected_text);
1478            log::info!(
1479                "fold text {:?} ({} lines)",
1480                expected_text,
1481                expected_text.matches('\n').count() + 1
1482            );
1483
1484            let mut prev_row = 0;
1485            let mut expected_buffer_rows = Vec::new();
1486            for fold_range in map.merged_fold_ranges().into_iter() {
1487                let fold_start = buffer_snapshot.offset_to_point(fold_range.start).row;
1488                let fold_end = buffer_snapshot.offset_to_point(fold_range.end).row;
1489                expected_buffer_rows.extend(
1490                    buffer_snapshot
1491                        .buffer_rows(prev_row)
1492                        .take((1 + fold_start - prev_row) as usize),
1493                );
1494                prev_row = 1 + fold_end;
1495            }
1496            expected_buffer_rows.extend(buffer_snapshot.buffer_rows(prev_row));
1497
1498            assert_eq!(
1499                expected_buffer_rows.len(),
1500                expected_text.matches('\n').count() + 1,
1501                "wrong expected buffer rows {:?}. text: {:?}",
1502                expected_buffer_rows,
1503                expected_text
1504            );
1505
1506            for (output_row, line) in expected_text.lines().enumerate() {
1507                let line_len = snapshot.line_len(output_row as u32);
1508                assert_eq!(line_len, line.len() as u32);
1509            }
1510
1511            let longest_row = snapshot.longest_row();
1512            let longest_char_column = expected_text
1513                .split('\n')
1514                .nth(longest_row as usize)
1515                .unwrap()
1516                .chars()
1517                .count();
1518            let mut fold_point = FoldPoint::new(0, 0);
1519            let mut fold_offset = FoldOffset(0);
1520            let mut char_column = 0;
1521            for c in expected_text.chars() {
1522                let buffer_point = fold_point.to_buffer_point(&snapshot);
1523                let buffer_offset = buffer_point.to_offset(&buffer_snapshot);
1524                assert_eq!(
1525                    snapshot.to_fold_point(buffer_point, Right),
1526                    fold_point,
1527                    "{:?} -> fold point",
1528                    buffer_point,
1529                );
1530                assert_eq!(
1531                    fold_point.to_buffer_offset(&snapshot),
1532                    buffer_offset,
1533                    "fold_point.to_buffer_offset({:?})",
1534                    fold_point,
1535                );
1536                assert_eq!(
1537                    fold_point.to_offset(&snapshot),
1538                    fold_offset,
1539                    "fold_point.to_offset({:?})",
1540                    fold_point,
1541                );
1542
1543                if c == '\n' {
1544                    *fold_point.row_mut() += 1;
1545                    *fold_point.column_mut() = 0;
1546                    char_column = 0;
1547                } else {
1548                    *fold_point.column_mut() += c.len_utf8() as u32;
1549                    char_column += 1;
1550                }
1551                fold_offset.0 += c.len_utf8();
1552                if char_column > longest_char_column {
1553                    panic!(
1554                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1555                        longest_row,
1556                        longest_char_column,
1557                        fold_point.row(),
1558                        char_column
1559                    );
1560                }
1561            }
1562
1563            for _ in 0..5 {
1564                let mut start = snapshot
1565                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1566                let mut end = snapshot
1567                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1568                if start > end {
1569                    mem::swap(&mut start, &mut end);
1570                }
1571
1572                let text = &expected_text[start.0..end.0];
1573                assert_eq!(
1574                    snapshot
1575                        .chunks(start..end, false, Some(&highlights))
1576                        .map(|c| c.text)
1577                        .collect::<String>(),
1578                    text,
1579                );
1580            }
1581
1582            let mut fold_row = 0;
1583            while fold_row < expected_buffer_rows.len() as u32 {
1584                fold_row = snapshot
1585                    .clip_point(FoldPoint::new(fold_row, 0), Bias::Right)
1586                    .row();
1587                assert_eq!(
1588                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1589                    expected_buffer_rows[(fold_row as usize)..],
1590                    "wrong buffer rows starting at fold row {}",
1591                    fold_row,
1592                );
1593                fold_row += 1;
1594            }
1595
1596            for fold_range in map.merged_fold_ranges() {
1597                let fold_point =
1598                    snapshot.to_fold_point(fold_range.start.to_point(&buffer_snapshot), Right);
1599                assert!(snapshot.is_line_folded(fold_point.row()));
1600            }
1601
1602            for _ in 0..5 {
1603                let end =
1604                    buffer_snapshot.clip_offset(rng.gen_range(0..=buffer_snapshot.len()), Right);
1605                let start = buffer_snapshot.clip_offset(rng.gen_range(0..=end), Left);
1606                let expected_folds = map
1607                    .folds
1608                    .items(&buffer_snapshot)
1609                    .into_iter()
1610                    .filter(|fold| {
1611                        let start = buffer_snapshot.anchor_before(start);
1612                        let end = buffer_snapshot.anchor_after(end);
1613                        start.cmp(&fold.0.end, &buffer_snapshot) == Ordering::Less
1614                            && end.cmp(&fold.0.start, &buffer_snapshot) == Ordering::Greater
1615                    })
1616                    .map(|fold| fold.0)
1617                    .collect::<Vec<_>>();
1618
1619                assert_eq!(
1620                    snapshot
1621                        .folds_in_range(start..end)
1622                        .cloned()
1623                        .collect::<Vec<_>>(),
1624                    expected_folds
1625                );
1626            }
1627
1628            let text = snapshot.text();
1629            for _ in 0..5 {
1630                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1631                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1632                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1633                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1634                let mut start =
1635                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1636                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1637                if start > end {
1638                    mem::swap(&mut start, &mut end);
1639                }
1640
1641                let lines = start..end;
1642                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1643                assert_eq!(
1644                    snapshot.text_summary_for_range(lines),
1645                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1646                )
1647            }
1648
1649            let mut text = initial_snapshot.text();
1650            for (snapshot, edits) in snapshot_edits.drain(..) {
1651                let new_text = snapshot.text();
1652                for edit in edits {
1653                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
1654                    let new_bytes = edit.new.start.0..edit.new.end.0;
1655                    text.replace_range(old_bytes, &new_text[new_bytes]);
1656                }
1657
1658                assert_eq!(text, new_text);
1659                initial_snapshot = snapshot;
1660            }
1661        }
1662    }
1663
1664    #[gpui::test]
1665    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1666        let text = sample_text(6, 6, 'a') + "\n";
1667        let buffer = MultiBuffer::build_simple(&text, cx);
1668
1669        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1670        let mut map = FoldMap::new(buffer_snapshot.clone()).0;
1671
1672        let (mut writer, _, _) = map.write(buffer_snapshot.clone(), vec![]);
1673        writer.fold(vec![
1674            Point::new(0, 2)..Point::new(2, 2),
1675            Point::new(3, 1)..Point::new(4, 1),
1676        ]);
1677
1678        let (snapshot, _) = map.read(buffer_snapshot, vec![]);
1679        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
1680        assert_eq!(
1681            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1682            [Some(0), Some(3), Some(5), Some(6)]
1683        );
1684        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
1685    }
1686
1687    impl FoldMap {
1688        fn merged_fold_ranges(&self) -> Vec<Range<usize>> {
1689            let buffer = self.buffer.lock().clone();
1690            let mut folds = self.folds.items(&buffer);
1691            // Ensure sorting doesn't change how folds get merged and displayed.
1692            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer));
1693            let mut fold_ranges = folds
1694                .iter()
1695                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1696                .peekable();
1697
1698            let mut merged_ranges = Vec::new();
1699            while let Some(mut fold_range) = fold_ranges.next() {
1700                while let Some(next_range) = fold_ranges.peek() {
1701                    if fold_range.end >= next_range.start {
1702                        if next_range.end > fold_range.end {
1703                            fold_range.end = next_range.end;
1704                        }
1705                        fold_ranges.next();
1706                    } else {
1707                        break;
1708                    }
1709                }
1710                if fold_range.end > fold_range.start {
1711                    merged_ranges.push(fold_range);
1712                }
1713            }
1714            merged_ranges
1715        }
1716
1717        pub fn randomly_mutate(
1718            &mut self,
1719            rng: &mut impl Rng,
1720        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
1721            let mut snapshot_edits = Vec::new();
1722            match rng.gen_range(0..=100) {
1723                0..=39 if !self.folds.is_empty() => {
1724                    let buffer = self.buffer.lock().clone();
1725                    let mut to_unfold = Vec::new();
1726                    for _ in 0..rng.gen_range(1..=3) {
1727                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1728                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1729                        to_unfold.push(start..end);
1730                    }
1731                    log::info!("unfolding {:?}", to_unfold);
1732                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1733                    snapshot_edits.push((snapshot, edits));
1734                    let (snapshot, edits) = writer.fold(to_unfold);
1735                    snapshot_edits.push((snapshot, edits));
1736                }
1737                _ => {
1738                    let buffer = self.buffer.lock().clone();
1739                    let mut to_fold = Vec::new();
1740                    for _ in 0..rng.gen_range(1..=2) {
1741                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1742                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1743                        to_fold.push(start..end);
1744                    }
1745                    log::info!("folding {:?}", to_fold);
1746                    let (mut writer, snapshot, edits) = self.write(buffer, vec![]);
1747                    snapshot_edits.push((snapshot, edits));
1748                    let (snapshot, edits) = writer.fold(to_fold);
1749                    snapshot_edits.push((snapshot, edits));
1750                }
1751            }
1752            snapshot_edits
1753        }
1754    }
1755}