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