fold_map.rs

   1use gpui::{AppContext, ModelHandle};
   2use language::{
   3    Anchor, AnchorRangeExt, Buffer, Chunk, HighlightId, Point, PointUtf16, TextSummary, ToOffset,
   4};
   5use parking_lot::Mutex;
   6use std::{
   7    cmp::{self, Ordering},
   8    iter, mem,
   9    ops::Range,
  10    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  11};
  12use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  13
  14pub trait ToFoldPoint {
  15    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint;
  16}
  17
  18#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  19pub struct FoldPoint(pub super::Point);
  20
  21impl FoldPoint {
  22    pub fn new(row: u32, column: u32) -> Self {
  23        Self(super::Point::new(row, column))
  24    }
  25
  26    pub fn row(self) -> u32 {
  27        self.0.row
  28    }
  29
  30    pub fn column(self) -> u32 {
  31        self.0.column
  32    }
  33
  34    pub fn row_mut(&mut self) -> &mut u32 {
  35        &mut self.0.row
  36    }
  37
  38    #[cfg(test)]
  39    pub fn column_mut(&mut self) -> &mut u32 {
  40        &mut self.0.column
  41    }
  42
  43    pub fn to_buffer_point(&self, snapshot: &Snapshot) -> Point {
  44        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  45        cursor.seek(self, Bias::Right, &());
  46        let overshoot = self.0 - cursor.start().0 .0;
  47        cursor.start().1 + overshoot
  48    }
  49
  50    pub fn to_buffer_offset(&self, snapshot: &Snapshot) -> usize {
  51        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  52        cursor.seek(self, Bias::Right, &());
  53        let overshoot = self.0 - cursor.start().0 .0;
  54        snapshot
  55            .buffer_snapshot
  56            .to_offset(cursor.start().1 + overshoot)
  57    }
  58
  59    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  60        let mut cursor = snapshot
  61            .transforms
  62            .cursor::<(FoldPoint, TransformSummary)>();
  63        cursor.seek(self, Bias::Right, &());
  64        let overshoot = self.0 - cursor.start().1.output.lines;
  65        let mut offset = cursor.start().1.output.bytes;
  66        if !overshoot.is_zero() {
  67            let transform = cursor.item().expect("display point out of range");
  68            assert!(transform.output_text.is_none());
  69            let end_buffer_offset = snapshot
  70                .buffer_snapshot
  71                .to_offset(cursor.start().1.input.lines + overshoot);
  72            offset += end_buffer_offset - cursor.start().1.input.bytes;
  73        }
  74        FoldOffset(offset)
  75    }
  76}
  77
  78impl ToFoldPoint for Point {
  79    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  80        let mut cursor = snapshot.transforms.cursor::<(Point, FoldPoint)>();
  81        cursor.seek(self, Bias::Right, &());
  82        if cursor.item().map_or(false, |t| t.is_fold()) {
  83            if bias == Bias::Left || *self == cursor.start().0 {
  84                cursor.start().1
  85            } else {
  86                cursor.end(&()).1
  87            }
  88        } else {
  89            let overshoot = *self - cursor.start().0;
  90            FoldPoint(cmp::min(
  91                cursor.start().1 .0 + overshoot,
  92                cursor.end(&()).1 .0,
  93            ))
  94        }
  95    }
  96}
  97
  98pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  99
 100impl<'a> FoldMapWriter<'a> {
 101    pub fn fold<T: ToOffset>(
 102        &mut self,
 103        ranges: impl IntoIterator<Item = Range<T>>,
 104        cx: &AppContext,
 105    ) -> (Snapshot, Vec<FoldEdit>) {
 106        let mut edits = Vec::new();
 107        let mut folds = Vec::new();
 108        let buffer = self.0.buffer.read(cx).snapshot();
 109        for range in ranges.into_iter() {
 110            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 111            if range.start != range.end {
 112                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 113                folds.push(fold);
 114                edits.push(buffer::Edit {
 115                    old: range.clone(),
 116                    new: range,
 117                });
 118            }
 119        }
 120
 121        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 122
 123        self.0.folds = {
 124            let mut new_tree = SumTree::new();
 125            let mut cursor = self.0.folds.cursor::<Fold>();
 126            for fold in folds {
 127                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 128                new_tree.push(fold, &buffer);
 129            }
 130            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 131            new_tree
 132        };
 133
 134        consolidate_buffer_edits(&mut edits);
 135        let edits = self.0.apply_edits(edits, cx);
 136        let snapshot = Snapshot {
 137            transforms: self.0.transforms.lock().clone(),
 138            folds: self.0.folds.clone(),
 139            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 140            version: self.0.version.load(SeqCst),
 141        };
 142        (snapshot, edits)
 143    }
 144
 145    pub fn unfold<T: ToOffset>(
 146        &mut self,
 147        ranges: impl IntoIterator<Item = Range<T>>,
 148        cx: &AppContext,
 149    ) -> (Snapshot, Vec<FoldEdit>) {
 150        let mut edits = Vec::new();
 151        let mut fold_ixs_to_delete = Vec::new();
 152        let buffer = self.0.buffer.read(cx).snapshot();
 153        for range in ranges.into_iter() {
 154            // Remove intersecting folds and add their ranges to edits that are passed to apply_edits.
 155            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 156            while let Some(fold) = folds_cursor.item() {
 157                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 158                edits.push(buffer::Edit {
 159                    old: offset_range.clone(),
 160                    new: offset_range,
 161                });
 162                fold_ixs_to_delete.push(*folds_cursor.start());
 163                folds_cursor.next(&buffer);
 164            }
 165        }
 166
 167        fold_ixs_to_delete.sort_unstable();
 168        fold_ixs_to_delete.dedup();
 169
 170        self.0.folds = {
 171            let mut cursor = self.0.folds.cursor::<usize>();
 172            let mut folds = SumTree::new();
 173            for fold_ix in fold_ixs_to_delete {
 174                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 175                cursor.next(&buffer);
 176            }
 177            folds.push_tree(cursor.suffix(&buffer), &buffer);
 178            folds
 179        };
 180
 181        consolidate_buffer_edits(&mut edits);
 182        let edits = self.0.apply_edits(edits, cx);
 183        let snapshot = Snapshot {
 184            transforms: self.0.transforms.lock().clone(),
 185            folds: self.0.folds.clone(),
 186            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 187            version: self.0.version.load(SeqCst),
 188        };
 189        (snapshot, edits)
 190    }
 191}
 192
 193pub struct FoldMap {
 194    buffer: ModelHandle<Buffer>,
 195    transforms: Mutex<SumTree<Transform>>,
 196    folds: SumTree<Fold>,
 197    last_sync: Mutex<SyncState>,
 198    version: AtomicUsize,
 199}
 200
 201#[derive(Clone)]
 202struct SyncState {
 203    version: clock::Global,
 204    parse_count: usize,
 205    diagnostics_update_count: usize,
 206}
 207
 208impl FoldMap {
 209    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
 210        let buffer = buffer_handle.read(cx);
 211        let this = Self {
 212            buffer: buffer_handle,
 213            folds: Default::default(),
 214            transforms: Mutex::new(SumTree::from_item(
 215                Transform {
 216                    summary: TransformSummary {
 217                        input: buffer.text_summary(),
 218                        output: buffer.text_summary(),
 219                    },
 220                    output_text: None,
 221                },
 222                &(),
 223            )),
 224            last_sync: Mutex::new(SyncState {
 225                version: buffer.version(),
 226                parse_count: buffer.parse_count(),
 227                diagnostics_update_count: buffer.diagnostics_update_count(),
 228            }),
 229            version: AtomicUsize::new(0),
 230        };
 231        let (snapshot, _) = this.read(cx);
 232        (this, snapshot)
 233    }
 234
 235    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 236        let edits = self.sync(cx);
 237        self.check_invariants(cx);
 238        let snapshot = Snapshot {
 239            transforms: self.transforms.lock().clone(),
 240            folds: self.folds.clone(),
 241            buffer_snapshot: self.buffer.read(cx).snapshot(),
 242            version: self.version.load(SeqCst),
 243        };
 244        (snapshot, edits)
 245    }
 246
 247    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 248        let (snapshot, edits) = self.read(cx);
 249        (FoldMapWriter(self), snapshot, edits)
 250    }
 251
 252    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 253        let buffer = self.buffer.read(cx);
 254        let last_sync = mem::replace(
 255            &mut *self.last_sync.lock(),
 256            SyncState {
 257                version: buffer.version(),
 258                parse_count: buffer.parse_count(),
 259                diagnostics_update_count: buffer.diagnostics_update_count(),
 260            },
 261        );
 262        let edits = buffer
 263            .edits_since(&last_sync.version)
 264            .map(Into::into)
 265            .collect::<Vec<_>>();
 266        if edits.is_empty() {
 267            if last_sync.parse_count != buffer.parse_count()
 268                || last_sync.diagnostics_update_count != buffer.diagnostics_update_count()
 269            {
 270                self.version.fetch_add(1, SeqCst);
 271            }
 272            Vec::new()
 273        } else {
 274            self.apply_edits(edits, cx)
 275        }
 276    }
 277
 278    fn check_invariants(&self, cx: &AppContext) {
 279        if cfg!(test) {
 280            let buffer = self.buffer.read(cx);
 281            assert_eq!(
 282                self.transforms.lock().summary().input.bytes,
 283                buffer.len(),
 284                "transform tree does not match buffer's length"
 285            );
 286        }
 287    }
 288
 289    fn apply_edits(
 290        &self,
 291        buffer_edits: Vec<buffer::Edit<usize>>,
 292        cx: &AppContext,
 293    ) -> Vec<FoldEdit> {
 294        let buffer = self.buffer.read(cx).snapshot();
 295        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 296
 297        let mut new_transforms = SumTree::new();
 298        let mut transforms = self.transforms.lock();
 299        let mut cursor = transforms.cursor::<usize>();
 300        cursor.seek(&0, Bias::Right, &());
 301
 302        while let Some(mut edit) = buffer_edits_iter.next() {
 303            new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
 304            edit.new.start -= edit.old.start - cursor.start();
 305            edit.old.start = *cursor.start();
 306
 307            cursor.seek(&edit.old.end, Bias::Right, &());
 308            cursor.next(&());
 309
 310            let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 311            loop {
 312                edit.old.end = *cursor.start();
 313
 314                if let Some(next_edit) = buffer_edits_iter.peek() {
 315                    if next_edit.old.start > edit.old.end {
 316                        break;
 317                    }
 318
 319                    let next_edit = buffer_edits_iter.next().unwrap();
 320                    delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 321
 322                    if next_edit.old.end >= edit.old.end {
 323                        edit.old.end = next_edit.old.end;
 324                        cursor.seek(&edit.old.end, Bias::Right, &());
 325                        cursor.next(&());
 326                    }
 327                } else {
 328                    break;
 329                }
 330            }
 331
 332            edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 333
 334            let anchor = buffer.anchor_before(edit.new.start);
 335            let mut folds_cursor = self.folds.cursor::<Fold>();
 336            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 337
 338            let mut folds = iter::from_fn({
 339                let buffer = &buffer;
 340                move || {
 341                    let item = folds_cursor
 342                        .item()
 343                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 344                    folds_cursor.next(buffer);
 345                    item
 346                }
 347            })
 348            .peekable();
 349
 350            while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 351                let mut fold = folds.next().unwrap();
 352                let sum = new_transforms.summary();
 353
 354                assert!(fold.start >= sum.input.bytes);
 355
 356                while folds
 357                    .peek()
 358                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 359                {
 360                    let next_fold = folds.next().unwrap();
 361                    if next_fold.end > fold.end {
 362                        fold.end = next_fold.end;
 363                    }
 364                }
 365
 366                if fold.start > sum.input.bytes {
 367                    let text_summary = buffer.text_summary_for_range(sum.input.bytes..fold.start);
 368                    new_transforms.push(
 369                        Transform {
 370                            summary: TransformSummary {
 371                                output: text_summary.clone(),
 372                                input: text_summary,
 373                            },
 374                            output_text: None,
 375                        },
 376                        &(),
 377                    );
 378                }
 379
 380                if fold.end > fold.start {
 381                    let output_text = "";
 382                    let chars = output_text.chars().count() as u32;
 383                    let lines = Point::new(0, output_text.len() as u32);
 384                    let lines_utf16 = PointUtf16::new(0, output_text.encode_utf16().count() as u32);
 385                    new_transforms.push(
 386                        Transform {
 387                            summary: TransformSummary {
 388                                output: TextSummary {
 389                                    bytes: output_text.len(),
 390                                    lines,
 391                                    lines_utf16,
 392                                    first_line_chars: chars,
 393                                    last_line_chars: chars,
 394                                    longest_row: 0,
 395                                    longest_row_chars: chars,
 396                                },
 397                                input: buffer.text_summary_for_range(fold.start..fold.end),
 398                            },
 399                            output_text: Some(output_text),
 400                        },
 401                        &(),
 402                    );
 403                }
 404            }
 405
 406            let sum = new_transforms.summary();
 407            if sum.input.bytes < edit.new.end {
 408                let text_summary = buffer.text_summary_for_range(sum.input.bytes..edit.new.end);
 409                new_transforms.push(
 410                    Transform {
 411                        summary: TransformSummary {
 412                            output: text_summary.clone(),
 413                            input: text_summary,
 414                        },
 415                        output_text: None,
 416                    },
 417                    &(),
 418                );
 419            }
 420        }
 421
 422        new_transforms.push_tree(cursor.suffix(&()), &());
 423        if new_transforms.is_empty() {
 424            let text_summary = buffer.text_summary();
 425            new_transforms.push(
 426                Transform {
 427                    summary: TransformSummary {
 428                        output: text_summary.clone(),
 429                        input: text_summary,
 430                    },
 431                    output_text: None,
 432                },
 433                &(),
 434            );
 435        }
 436
 437        drop(cursor);
 438
 439        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 440        {
 441            let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 442            let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 443
 444            for mut edit in buffer_edits {
 445                old_transforms.seek(&edit.old.start, Bias::Left, &());
 446                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 447                    edit.old.start = old_transforms.start().0;
 448                }
 449                let old_start =
 450                    old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 451
 452                old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 453                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 454                    old_transforms.next(&());
 455                    edit.old.end = old_transforms.start().0;
 456                }
 457                let old_end =
 458                    old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 459
 460                new_transforms.seek(&edit.new.start, Bias::Left, &());
 461                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 462                    edit.new.start = new_transforms.start().0;
 463                }
 464                let new_start =
 465                    new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 466
 467                new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 468                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 469                    new_transforms.next(&());
 470                    edit.new.end = new_transforms.start().0;
 471                }
 472                let new_end =
 473                    new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 474
 475                fold_edits.push(FoldEdit {
 476                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 477                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 478                });
 479            }
 480
 481            consolidate_fold_edits(&mut fold_edits);
 482        }
 483
 484        *transforms = new_transforms;
 485        self.version.fetch_add(1, SeqCst);
 486        fold_edits
 487    }
 488}
 489
 490#[derive(Clone)]
 491pub struct Snapshot {
 492    transforms: SumTree<Transform>,
 493    folds: SumTree<Fold>,
 494    buffer_snapshot: language::Snapshot,
 495    pub version: usize,
 496}
 497
 498impl Snapshot {
 499    #[cfg(test)]
 500    pub fn text(&self) -> String {
 501        self.chunks(FoldOffset(0)..self.len(), false)
 502            .map(|c| c.text)
 503            .collect()
 504    }
 505
 506    #[cfg(test)]
 507    pub fn fold_count(&self) -> usize {
 508        self.folds.items(&self.buffer_snapshot).len()
 509    }
 510
 511    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 512        let mut summary = TextSummary::default();
 513
 514        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 515        cursor.seek(&range.start, Bias::Right, &());
 516        if let Some(transform) = cursor.item() {
 517            let start_in_transform = range.start.0 - cursor.start().0 .0;
 518            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 519            if let Some(output_text) = transform.output_text {
 520                summary = TextSummary::from(
 521                    &output_text
 522                        [start_in_transform.column as usize..end_in_transform.column as usize],
 523                );
 524            } else {
 525                let buffer_start = cursor.start().1 + start_in_transform;
 526                let buffer_end = cursor.start().1 + end_in_transform;
 527                summary = self
 528                    .buffer_snapshot
 529                    .text_summary_for_range(buffer_start..buffer_end);
 530            }
 531        }
 532
 533        if range.end > cursor.end(&()).0 {
 534            cursor.next(&());
 535            summary += &cursor
 536                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 537                .output;
 538            if let Some(transform) = cursor.item() {
 539                let end_in_transform = range.end.0 - cursor.start().0 .0;
 540                if let Some(output_text) = transform.output_text {
 541                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 542                } else {
 543                    let buffer_start = cursor.start().1;
 544                    let buffer_end = cursor.start().1 + end_in_transform;
 545                    summary += self
 546                        .buffer_snapshot
 547                        .text_summary_for_range(buffer_start..buffer_end);
 548                }
 549            }
 550        }
 551
 552        summary
 553    }
 554
 555    pub fn len(&self) -> FoldOffset {
 556        FoldOffset(self.transforms.summary().output.bytes)
 557    }
 558
 559    #[cfg(test)]
 560    pub fn line_len(&self, row: u32) -> u32 {
 561        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 562        let line_end = if row >= self.max_point().row() {
 563            self.len().0
 564        } else {
 565            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 566        };
 567        (line_end - line_start) as u32
 568    }
 569
 570    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 571        if start_row > self.transforms.summary().output.lines.row {
 572            panic!("invalid display row {}", start_row);
 573        }
 574
 575        let fold_point = FoldPoint::new(start_row, 0);
 576        let mut cursor = self.transforms.cursor();
 577        cursor.seek(&fold_point, Bias::Left, &());
 578        BufferRows { fold_point, cursor }
 579    }
 580
 581    pub fn max_point(&self) -> FoldPoint {
 582        FoldPoint(self.transforms.summary().output.lines)
 583    }
 584
 585    #[cfg(test)]
 586    pub fn longest_row(&self) -> u32 {
 587        self.transforms.summary().output.longest_row
 588    }
 589
 590    pub fn folds_in_range<'a, T>(
 591        &'a self,
 592        range: Range<T>,
 593    ) -> impl Iterator<Item = &'a Range<Anchor>>
 594    where
 595        T: ToOffset,
 596    {
 597        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 598        iter::from_fn(move || {
 599            let item = folds.item().map(|f| &f.0);
 600            folds.next(&self.buffer_snapshot);
 601            item
 602        })
 603    }
 604
 605    pub fn intersects_fold<T>(&self, offset: T) -> bool
 606    where
 607        T: ToOffset,
 608    {
 609        let offset = offset.to_offset(&self.buffer_snapshot);
 610        let mut cursor = self.transforms.cursor::<usize>();
 611        cursor.seek(&offset, Bias::Right, &());
 612        cursor.item().map_or(false, |t| t.output_text.is_some())
 613    }
 614
 615    pub fn is_line_folded(&self, output_row: u32) -> bool {
 616        let mut cursor = self.transforms.cursor::<FoldPoint>();
 617        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 618        while let Some(transform) = cursor.item() {
 619            if transform.output_text.is_some() {
 620                return true;
 621            }
 622            if cursor.end(&()).row() == output_row {
 623                cursor.next(&())
 624            } else {
 625                break;
 626            }
 627        }
 628        false
 629    }
 630
 631    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 632        let start = start.to_offset(self);
 633        self.chunks(start..self.len(), false)
 634            .flat_map(|chunk| chunk.text.chars())
 635    }
 636
 637    pub fn chunks(&self, range: Range<FoldOffset>, enable_highlights: bool) -> Chunks {
 638        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 639
 640        transform_cursor.seek(&range.end, Bias::Right, &());
 641        let overshoot = range.end.0 - transform_cursor.start().0 .0;
 642        let buffer_end = transform_cursor.start().1 + overshoot;
 643
 644        transform_cursor.seek(&range.start, Bias::Right, &());
 645        let overshoot = range.start.0 - transform_cursor.start().0 .0;
 646        let buffer_start = transform_cursor.start().1 + overshoot;
 647
 648        Chunks {
 649            transform_cursor,
 650            buffer_offset: buffer_start,
 651            buffer_chunks: self
 652                .buffer_snapshot
 653                .chunks(buffer_start..buffer_end, enable_highlights),
 654            buffer_chunk: None,
 655        }
 656    }
 657
 658    #[cfg(test)]
 659    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 660        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 661        cursor.seek(&offset, Bias::Right, &());
 662        if let Some(transform) = cursor.item() {
 663            let transform_start = cursor.start().0 .0;
 664            if transform.output_text.is_some() {
 665                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 666                    FoldOffset(transform_start)
 667                } else {
 668                    FoldOffset(cursor.end(&()).0 .0)
 669                }
 670            } else {
 671                let overshoot = offset.0 - transform_start;
 672                let buffer_offset = cursor.start().1 + overshoot;
 673                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 674                FoldOffset(
 675                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 676                        as usize,
 677                )
 678            }
 679        } else {
 680            FoldOffset(self.transforms.summary().output.bytes)
 681        }
 682    }
 683
 684    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 685        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 686        cursor.seek(&point, Bias::Right, &());
 687        if let Some(transform) = cursor.item() {
 688            let transform_start = cursor.start().0 .0;
 689            if transform.output_text.is_some() {
 690                if point.0 == transform_start || matches!(bias, Bias::Left) {
 691                    FoldPoint(transform_start)
 692                } else {
 693                    FoldPoint(cursor.end(&()).0 .0)
 694                }
 695            } else {
 696                let overshoot = point.0 - transform_start;
 697                let buffer_position = cursor.start().1 + overshoot;
 698                let clipped_buffer_position =
 699                    self.buffer_snapshot.clip_point(buffer_position, bias);
 700                FoldPoint::new(
 701                    point.row(),
 702                    ((point.column() as i32) + clipped_buffer_position.column as i32
 703                        - buffer_position.column as i32) as u32,
 704                )
 705            }
 706        } else {
 707            FoldPoint(self.transforms.summary().output.lines)
 708        }
 709    }
 710}
 711
 712fn intersecting_folds<'a, T>(
 713    buffer: &'a buffer::Snapshot,
 714    folds: &'a SumTree<Fold>,
 715    range: Range<T>,
 716    inclusive: bool,
 717) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 718where
 719    T: ToOffset,
 720{
 721    let start = buffer.anchor_before(range.start.to_offset(buffer));
 722    let end = buffer.anchor_after(range.end.to_offset(buffer));
 723    folds.filter::<_, usize>(
 724        move |summary| {
 725            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 726            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 727
 728            if inclusive {
 729                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 730            } else {
 731                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 732            }
 733        },
 734        buffer,
 735    )
 736}
 737
 738fn consolidate_buffer_edits(edits: &mut Vec<buffer::Edit<usize>>) {
 739    edits.sort_unstable_by(|a, b| {
 740        a.old
 741            .start
 742            .cmp(&b.old.start)
 743            .then_with(|| b.old.end.cmp(&a.old.end))
 744    });
 745
 746    let mut i = 1;
 747    while i < edits.len() {
 748        let edit = edits[i].clone();
 749        let prev_edit = &mut edits[i - 1];
 750        if prev_edit.old.end >= edit.old.start {
 751            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 752            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 753            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 754            edits.remove(i);
 755            continue;
 756        }
 757        i += 1;
 758    }
 759}
 760
 761fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 762    edits.sort_unstable_by(|a, b| {
 763        a.old_bytes
 764            .start
 765            .cmp(&b.old_bytes.start)
 766            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 767    });
 768
 769    let mut i = 1;
 770    while i < edits.len() {
 771        let edit = edits[i].clone();
 772        let prev_edit = &mut edits[i - 1];
 773        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 774            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 775            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 776            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 777            edits.remove(i);
 778            continue;
 779        }
 780        i += 1;
 781    }
 782}
 783
 784#[derive(Clone, Debug, Default, Eq, PartialEq)]
 785struct Transform {
 786    summary: TransformSummary,
 787    output_text: Option<&'static str>,
 788}
 789
 790impl Transform {
 791    fn is_fold(&self) -> bool {
 792        self.output_text.is_some()
 793    }
 794}
 795
 796#[derive(Clone, Debug, Default, Eq, PartialEq)]
 797struct TransformSummary {
 798    output: TextSummary,
 799    input: TextSummary,
 800}
 801
 802impl sum_tree::Item for Transform {
 803    type Summary = TransformSummary;
 804
 805    fn summary(&self) -> Self::Summary {
 806        self.summary.clone()
 807    }
 808}
 809
 810impl sum_tree::Summary for TransformSummary {
 811    type Context = ();
 812
 813    fn add_summary(&mut self, other: &Self, _: &()) {
 814        self.input += &other.input;
 815        self.output += &other.output;
 816    }
 817}
 818
 819#[derive(Clone, Debug)]
 820struct Fold(Range<Anchor>);
 821
 822impl Default for Fold {
 823    fn default() -> Self {
 824        Self(Anchor::min()..Anchor::max())
 825    }
 826}
 827
 828impl sum_tree::Item for Fold {
 829    type Summary = FoldSummary;
 830
 831    fn summary(&self) -> Self::Summary {
 832        FoldSummary {
 833            start: self.0.start.clone(),
 834            end: self.0.end.clone(),
 835            min_start: self.0.start.clone(),
 836            max_end: self.0.end.clone(),
 837            count: 1,
 838        }
 839    }
 840}
 841
 842#[derive(Clone, Debug)]
 843struct FoldSummary {
 844    start: Anchor,
 845    end: Anchor,
 846    min_start: Anchor,
 847    max_end: Anchor,
 848    count: usize,
 849}
 850
 851impl Default for FoldSummary {
 852    fn default() -> Self {
 853        Self {
 854            start: Anchor::min(),
 855            end: Anchor::max(),
 856            min_start: Anchor::max(),
 857            max_end: Anchor::min(),
 858            count: 0,
 859        }
 860    }
 861}
 862
 863impl sum_tree::Summary for FoldSummary {
 864    type Context = buffer::Snapshot;
 865
 866    fn add_summary(&mut self, other: &Self, buffer: &buffer::Snapshot) {
 867        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 868            self.min_start = other.min_start.clone();
 869        }
 870        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 871            self.max_end = other.max_end.clone();
 872        }
 873
 874        #[cfg(debug_assertions)]
 875        {
 876            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 877            assert!(start_comparison <= Ordering::Equal);
 878            if start_comparison == Ordering::Equal {
 879                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 880            }
 881        }
 882
 883        self.start = other.start.clone();
 884        self.end = other.end.clone();
 885        self.count += other.count;
 886    }
 887}
 888
 889impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 890    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 891        self.0.start = summary.start.clone();
 892        self.0.end = summary.end.clone();
 893    }
 894}
 895
 896impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 897    fn cmp(&self, other: &Self, buffer: &buffer::Snapshot) -> Ordering {
 898        self.0.cmp(&other.0, buffer).unwrap()
 899    }
 900}
 901
 902impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 903    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 904        *self += summary.count;
 905    }
 906}
 907
 908pub struct BufferRows<'a> {
 909    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 910    fold_point: FoldPoint,
 911}
 912
 913impl<'a> Iterator for BufferRows<'a> {
 914    type Item = u32;
 915
 916    fn next(&mut self) -> Option<Self::Item> {
 917        while self.fold_point > self.cursor.end(&()).0 {
 918            self.cursor.next(&());
 919            if self.cursor.item().is_none() {
 920                // TODO: Return a bool from next?
 921                break;
 922            }
 923        }
 924
 925        if self.cursor.item().is_some() {
 926            let overshoot = self.fold_point.0 - self.cursor.start().0 .0;
 927            let buffer_point = self.cursor.start().1 + overshoot;
 928            *self.fold_point.row_mut() += 1;
 929            Some(buffer_point.row)
 930        } else {
 931            None
 932        }
 933    }
 934}
 935
 936pub struct Chunks<'a> {
 937    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 938    buffer_chunks: language::Chunks<'a>,
 939    buffer_chunk: Option<(usize, Chunk<'a>)>,
 940    buffer_offset: usize,
 941}
 942
 943impl<'a> Iterator for Chunks<'a> {
 944    type Item = Chunk<'a>;
 945
 946    fn next(&mut self) -> Option<Self::Item> {
 947        let transform = if let Some(item) = self.transform_cursor.item() {
 948            item
 949        } else {
 950            return None;
 951        };
 952
 953        // If we're in a fold, then return the fold's display text and
 954        // advance the transform and buffer cursors to the end of the fold.
 955        if let Some(output_text) = transform.output_text {
 956            self.buffer_chunk.take();
 957            self.buffer_offset += transform.summary.input.bytes;
 958            self.buffer_chunks.seek(self.buffer_offset);
 959
 960            while self.buffer_offset >= self.transform_cursor.end(&()).1
 961                && self.transform_cursor.item().is_some()
 962            {
 963                self.transform_cursor.next(&());
 964            }
 965
 966            return Some(Chunk {
 967                text: output_text,
 968                highlight_id: HighlightId::default(),
 969                diagnostic: None,
 970            });
 971        }
 972
 973        // Retrieve a chunk from the current location in the buffer.
 974        if self.buffer_chunk.is_none() {
 975            let chunk_offset = self.buffer_chunks.offset();
 976            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
 977        }
 978
 979        // Otherwise, take a chunk from the buffer's text.
 980        if let Some((chunk_offset, mut chunk)) = self.buffer_chunk {
 981            let offset_in_chunk = self.buffer_offset - chunk_offset;
 982            chunk.text = &chunk.text[offset_in_chunk..];
 983
 984            // Truncate the chunk so that it ends at the next fold.
 985            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
 986            if chunk.text.len() >= region_end {
 987                chunk.text = &chunk.text[0..region_end];
 988                self.transform_cursor.next(&());
 989            } else {
 990                self.buffer_chunk.take();
 991            }
 992
 993            self.buffer_offset += chunk.text.len();
 994            return Some(chunk);
 995        }
 996
 997        None
 998    }
 999}
1000
1001impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1002    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1003        self.0 += &summary.output.lines;
1004    }
1005}
1006
1007#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1008pub struct FoldOffset(pub usize);
1009
1010impl FoldOffset {
1011    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1012        let mut cursor = snapshot
1013            .transforms
1014            .cursor::<(FoldOffset, TransformSummary)>();
1015        cursor.seek(self, Bias::Right, &());
1016        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1017            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1018        } else {
1019            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1020            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1021            buffer_point - cursor.start().1.input.lines
1022        };
1023        FoldPoint(cursor.start().1.output.lines + overshoot)
1024    }
1025}
1026
1027impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1028    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1029        self.0 += &summary.output.bytes;
1030    }
1031}
1032
1033impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1034    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1035        *self += &summary.input.lines;
1036    }
1037}
1038
1039impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1040    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1041        *self += &summary.input.bytes;
1042    }
1043}
1044
1045#[derive(Clone, Debug, PartialEq, Eq)]
1046pub struct FoldEdit {
1047    pub old_bytes: Range<FoldOffset>,
1048    pub new_bytes: Range<FoldOffset>,
1049}
1050
1051#[cfg(test)]
1052impl FoldEdit {
1053    pub fn delta(&self) -> isize {
1054        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1055    }
1056
1057    pub fn deleted_bytes(&self) -> usize {
1058        self.old_bytes.end.0 - self.old_bytes.start.0
1059    }
1060
1061    pub fn inserted_bytes(&self) -> usize {
1062        self.new_bytes.end.0 - self.new_bytes.start.0
1063    }
1064}
1065
1066#[cfg(test)]
1067mod tests {
1068    use super::*;
1069    use crate::{test::sample_text, ToPoint};
1070    use buffer::RandomCharIter;
1071    use rand::prelude::*;
1072    use std::{env, mem};
1073    use Bias::{Left, Right};
1074
1075    #[gpui::test]
1076    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1077        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1078        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1079
1080        let (mut writer, _, _) = map.write(cx.as_ref());
1081        let (snapshot2, edits) = writer.fold(
1082            vec![
1083                Point::new(0, 2)..Point::new(2, 2),
1084                Point::new(2, 4)..Point::new(4, 1),
1085            ],
1086            cx.as_ref(),
1087        );
1088        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1089        assert_eq!(
1090            edits,
1091            &[
1092                FoldEdit {
1093                    old_bytes: FoldOffset(2)..FoldOffset(16),
1094                    new_bytes: FoldOffset(2)..FoldOffset(5),
1095                },
1096                FoldEdit {
1097                    old_bytes: FoldOffset(18)..FoldOffset(29),
1098                    new_bytes: FoldOffset(7)..FoldOffset(10)
1099                },
1100            ]
1101        );
1102
1103        buffer.update(cx, |buffer, cx| {
1104            buffer.edit(
1105                vec![
1106                    Point::new(0, 0)..Point::new(0, 1),
1107                    Point::new(2, 3)..Point::new(2, 3),
1108                ],
1109                "123",
1110                cx,
1111            );
1112        });
1113        let (snapshot3, edits) = map.read(cx.as_ref());
1114        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1115        assert_eq!(
1116            edits,
1117            &[
1118                FoldEdit {
1119                    old_bytes: FoldOffset(0)..FoldOffset(1),
1120                    new_bytes: FoldOffset(0)..FoldOffset(3),
1121                },
1122                FoldEdit {
1123                    old_bytes: FoldOffset(6)..FoldOffset(6),
1124                    new_bytes: FoldOffset(8)..FoldOffset(11),
1125                },
1126            ]
1127        );
1128
1129        buffer.update(cx, |buffer, cx| {
1130            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx)
1131        });
1132        let (snapshot4, _) = map.read(cx.as_ref());
1133        assert_eq!(snapshot4.text(), "123a…c123456eee");
1134
1135        let (mut writer, _, _) = map.write(cx.as_ref());
1136        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), cx.as_ref());
1137        let (snapshot5, _) = map.read(cx.as_ref());
1138        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1139    }
1140
1141    #[gpui::test]
1142    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1143        let buffer = cx.add_model(|cx| Buffer::new(0, "abcdefghijkl", cx));
1144
1145        {
1146            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1147
1148            let (mut writer, _, _) = map.write(cx.as_ref());
1149            writer.fold(vec![5..8], cx.as_ref());
1150            let (snapshot, _) = map.read(cx.as_ref());
1151            assert_eq!(snapshot.text(), "abcde…ijkl");
1152
1153            // Create an fold adjacent to the start of the first fold.
1154            let (mut writer, _, _) = map.write(cx.as_ref());
1155            writer.fold(vec![0..1, 2..5], cx.as_ref());
1156            let (snapshot, _) = map.read(cx.as_ref());
1157            assert_eq!(snapshot.text(), "…b…ijkl");
1158
1159            // Create an fold adjacent to the end of the first fold.
1160            let (mut writer, _, _) = map.write(cx.as_ref());
1161            writer.fold(vec![11..11, 8..10], cx.as_ref());
1162            let (snapshot, _) = map.read(cx.as_ref());
1163            assert_eq!(snapshot.text(), "…b…kl");
1164        }
1165
1166        {
1167            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1168
1169            // Create two adjacent folds.
1170            let (mut writer, _, _) = map.write(cx.as_ref());
1171            writer.fold(vec![0..2, 2..5], cx.as_ref());
1172            let (snapshot, _) = map.read(cx.as_ref());
1173            assert_eq!(snapshot.text(), "…fghijkl");
1174
1175            // Edit within one of the folds.
1176            buffer.update(cx, |buffer, cx| buffer.edit(vec![0..1], "12345", cx));
1177            let (snapshot, _) = map.read(cx.as_ref());
1178            assert_eq!(snapshot.text(), "12345…fghijkl");
1179        }
1180    }
1181
1182    #[gpui::test]
1183    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1184        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1185        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1186        let (mut writer, _, _) = map.write(cx.as_ref());
1187        writer.fold(
1188            vec![
1189                Point::new(0, 2)..Point::new(2, 2),
1190                Point::new(0, 4)..Point::new(1, 0),
1191                Point::new(1, 2)..Point::new(3, 2),
1192                Point::new(3, 1)..Point::new(4, 1),
1193            ],
1194            cx.as_ref(),
1195        );
1196        let (snapshot, _) = map.read(cx.as_ref());
1197        assert_eq!(snapshot.text(), "aa…eeeee");
1198    }
1199
1200    #[gpui::test]
1201    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1202        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1203        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1204
1205        let (mut writer, _, _) = map.write(cx.as_ref());
1206        writer.fold(
1207            vec![
1208                Point::new(0, 2)..Point::new(2, 2),
1209                Point::new(3, 1)..Point::new(4, 1),
1210            ],
1211            cx.as_ref(),
1212        );
1213        let (snapshot, _) = map.read(cx.as_ref());
1214        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1215
1216        buffer.update(cx, |buffer, cx| {
1217            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx)
1218        });
1219        let (snapshot, _) = map.read(cx.as_ref());
1220        assert_eq!(snapshot.text(), "aa…eeeee");
1221    }
1222
1223    #[gpui::test]
1224    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1225        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1226        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1227        let buffer = buffer.read(cx);
1228
1229        let (mut writer, _, _) = map.write(cx.as_ref());
1230        writer.fold(
1231            vec![
1232                Point::new(0, 2)..Point::new(2, 2),
1233                Point::new(0, 4)..Point::new(1, 0),
1234                Point::new(1, 2)..Point::new(3, 2),
1235                Point::new(3, 1)..Point::new(4, 1),
1236            ],
1237            cx.as_ref(),
1238        );
1239        let (snapshot, _) = map.read(cx.as_ref());
1240        let fold_ranges = snapshot
1241            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1242            .map(|fold| fold.start.to_point(buffer)..fold.end.to_point(buffer))
1243            .collect::<Vec<_>>();
1244        assert_eq!(
1245            fold_ranges,
1246            vec![
1247                Point::new(0, 2)..Point::new(2, 2),
1248                Point::new(1, 2)..Point::new(3, 2)
1249            ]
1250        );
1251    }
1252
1253    #[gpui::test(iterations = 100)]
1254    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1255        let operations = env::var("OPERATIONS")
1256            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1257            .unwrap_or(10);
1258
1259        let buffer = cx.add_model(|cx| {
1260            let len = rng.gen_range(0..10);
1261            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1262            Buffer::new(0, text, cx)
1263        });
1264        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1265
1266        let (mut initial_snapshot, _) = map.read(cx.as_ref());
1267        let mut snapshot_edits = Vec::new();
1268
1269        for _ in 0..operations {
1270            log::info!("text: {:?}", buffer.read(cx).text());
1271            match rng.gen_range(0..=100) {
1272                0..=59 => {
1273                    snapshot_edits.extend(map.randomly_mutate(&mut rng, cx.as_ref()));
1274                }
1275                _ => {
1276                    let edits = buffer.update(cx, |buffer, _| {
1277                        let start_version = buffer.version.clone();
1278                        let edit_count = rng.gen_range(1..=5);
1279                        buffer.randomly_edit(&mut rng, edit_count);
1280                        buffer
1281                            .edits_since::<Point>(&start_version)
1282                            .collect::<Vec<_>>()
1283                    });
1284                    log::info!("editing {:?}", edits);
1285                }
1286            }
1287
1288            let buffer = map.buffer.read(cx).snapshot();
1289            let mut expected_text: String = buffer.text().to_string();
1290            let mut expected_buffer_rows = Vec::new();
1291            let mut next_row = buffer.max_point().row;
1292            for fold_range in map.merged_fold_ranges(cx.as_ref()).into_iter().rev() {
1293                let fold_start = buffer.point_for_offset(fold_range.start).unwrap();
1294                let fold_end = buffer.point_for_offset(fold_range.end).unwrap();
1295                expected_buffer_rows.extend((fold_end.row + 1..=next_row).rev());
1296                next_row = fold_start.row;
1297
1298                expected_text.replace_range(fold_range.start..fold_range.end, "");
1299            }
1300            expected_buffer_rows.extend((0..=next_row).rev());
1301            expected_buffer_rows.reverse();
1302
1303            let (snapshot, edits) = map.read(cx.as_ref());
1304            assert_eq!(snapshot.text(), expected_text);
1305            snapshot_edits.push((snapshot.clone(), edits));
1306
1307            for (output_row, line) in expected_text.lines().enumerate() {
1308                let line_len = snapshot.line_len(output_row as u32);
1309                assert_eq!(line_len, line.len() as u32);
1310            }
1311
1312            let longest_row = snapshot.longest_row();
1313            let longest_char_column = expected_text
1314                .split('\n')
1315                .nth(longest_row as usize)
1316                .unwrap()
1317                .chars()
1318                .count();
1319            let mut fold_point = FoldPoint::new(0, 0);
1320            let mut fold_offset = FoldOffset(0);
1321            let mut char_column = 0;
1322            for c in expected_text.chars() {
1323                let buffer_point = fold_point.to_buffer_point(&snapshot);
1324                let buffer_offset = buffer_point.to_offset(&buffer);
1325                assert_eq!(
1326                    buffer_point.to_fold_point(&snapshot, Right),
1327                    fold_point,
1328                    "{:?} -> fold point",
1329                    buffer_point,
1330                );
1331                assert_eq!(
1332                    fold_point.to_buffer_offset(&snapshot),
1333                    buffer_offset,
1334                    "fold_point.to_buffer_offset({:?})",
1335                    fold_point,
1336                );
1337                assert_eq!(
1338                    fold_point.to_offset(&snapshot),
1339                    fold_offset,
1340                    "fold_point.to_offset({:?})",
1341                    fold_point,
1342                );
1343
1344                if c == '\n' {
1345                    *fold_point.row_mut() += 1;
1346                    *fold_point.column_mut() = 0;
1347                    char_column = 0;
1348                } else {
1349                    *fold_point.column_mut() += c.len_utf8() as u32;
1350                    char_column += 1;
1351                }
1352                fold_offset.0 += c.len_utf8();
1353                if char_column > longest_char_column {
1354                    panic!(
1355                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1356                        longest_row,
1357                        longest_char_column,
1358                        fold_point.row(),
1359                        char_column
1360                    );
1361                }
1362            }
1363
1364            for _ in 0..5 {
1365                let start = snapshot
1366                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1367                assert_eq!(
1368                    snapshot
1369                        .chunks(start..snapshot.len(), false)
1370                        .map(|c| c.text)
1371                        .collect::<String>(),
1372                    &expected_text[start.0..],
1373                );
1374            }
1375
1376            for (idx, buffer_row) in expected_buffer_rows.iter().enumerate() {
1377                let fold_row = Point::new(*buffer_row, 0)
1378                    .to_fold_point(&snapshot, Right)
1379                    .row();
1380                assert_eq!(
1381                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1382                    expected_buffer_rows[idx..],
1383                );
1384            }
1385
1386            for fold_range in map.merged_fold_ranges(cx.as_ref()) {
1387                let fold_point = fold_range
1388                    .start
1389                    .to_point(&buffer)
1390                    .to_fold_point(&snapshot, Right);
1391                assert!(snapshot.is_line_folded(fold_point.row()));
1392            }
1393
1394            for _ in 0..5 {
1395                let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1396                let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1397                let expected_folds = map
1398                    .folds
1399                    .items(&buffer)
1400                    .into_iter()
1401                    .filter(|fold| {
1402                        let start = buffer.anchor_before(start);
1403                        let end = buffer.anchor_after(end);
1404                        start.cmp(&fold.0.end, &buffer).unwrap() == Ordering::Less
1405                            && end.cmp(&fold.0.start, &buffer).unwrap() == Ordering::Greater
1406                    })
1407                    .map(|fold| fold.0)
1408                    .collect::<Vec<_>>();
1409
1410                assert_eq!(
1411                    snapshot
1412                        .folds_in_range(start..end)
1413                        .cloned()
1414                        .collect::<Vec<_>>(),
1415                    expected_folds
1416                );
1417            }
1418
1419            let text = snapshot.text();
1420            for _ in 0..5 {
1421                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1422                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1423                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1424                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1425                let mut start =
1426                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1427                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1428                if start > end {
1429                    mem::swap(&mut start, &mut end);
1430                }
1431
1432                let lines = start..end;
1433                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1434                assert_eq!(
1435                    snapshot.text_summary_for_range(lines),
1436                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1437                )
1438            }
1439
1440            let mut text = initial_snapshot.text();
1441            for (snapshot, edits) in snapshot_edits.drain(..) {
1442                let new_text = snapshot.text();
1443                let mut delta = 0isize;
1444                for edit in edits {
1445                    let old_bytes = ((edit.old_bytes.start.0 as isize) + delta) as usize
1446                        ..((edit.old_bytes.end.0 as isize) + delta) as usize;
1447                    let new_bytes = edit.new_bytes.start.0..edit.new_bytes.end.0;
1448                    delta += edit.delta();
1449                    text.replace_range(old_bytes, &new_text[new_bytes]);
1450                }
1451
1452                assert_eq!(text, new_text);
1453                initial_snapshot = snapshot;
1454            }
1455        }
1456    }
1457
1458    #[gpui::test]
1459    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1460        let text = sample_text(6, 6) + "\n";
1461        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1462
1463        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1464
1465        let (mut writer, _, _) = map.write(cx.as_ref());
1466        writer.fold(
1467            vec![
1468                Point::new(0, 2)..Point::new(2, 2),
1469                Point::new(3, 1)..Point::new(4, 1),
1470            ],
1471            cx.as_ref(),
1472        );
1473
1474        let (snapshot, _) = map.read(cx.as_ref());
1475        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1476        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), [0, 3, 5, 6]);
1477        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [6]);
1478    }
1479
1480    impl FoldMap {
1481        fn merged_fold_ranges(&self, cx: &AppContext) -> Vec<Range<usize>> {
1482            let buffer = self.buffer.read(cx).snapshot();
1483            let mut folds = self.folds.items(&buffer);
1484            // Ensure sorting doesn't change how folds get merged and displayed.
1485            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1486            let mut fold_ranges = folds
1487                .iter()
1488                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1489                .peekable();
1490
1491            let mut merged_ranges = Vec::new();
1492            while let Some(mut fold_range) = fold_ranges.next() {
1493                while let Some(next_range) = fold_ranges.peek() {
1494                    if fold_range.end >= next_range.start {
1495                        if next_range.end > fold_range.end {
1496                            fold_range.end = next_range.end;
1497                        }
1498                        fold_ranges.next();
1499                    } else {
1500                        break;
1501                    }
1502                }
1503                if fold_range.end > fold_range.start {
1504                    merged_ranges.push(fold_range);
1505                }
1506            }
1507            merged_ranges
1508        }
1509
1510        pub fn randomly_mutate(
1511            &mut self,
1512            rng: &mut impl Rng,
1513            cx: &AppContext,
1514        ) -> Vec<(Snapshot, Vec<FoldEdit>)> {
1515            let mut snapshot_edits = Vec::new();
1516            match rng.gen_range(0..=100) {
1517                0..=39 if !self.folds.is_empty() => {
1518                    let buffer = self.buffer.read(cx);
1519                    let mut to_unfold = Vec::new();
1520                    for _ in 0..rng.gen_range(1..=3) {
1521                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1522                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1523                        to_unfold.push(start..end);
1524                    }
1525                    log::info!("unfolding {:?}", to_unfold);
1526                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1527                    snapshot_edits.push((snapshot, edits));
1528                    let (snapshot, edits) = writer.fold(to_unfold, cx.as_ref());
1529                    snapshot_edits.push((snapshot, edits));
1530                }
1531                _ => {
1532                    let buffer = self.buffer.read(cx);
1533                    let mut to_fold = Vec::new();
1534                    for _ in 0..rng.gen_range(1..=2) {
1535                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1536                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1537                        to_fold.push(start..end);
1538                    }
1539                    log::info!("folding {:?}", to_fold);
1540                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1541                    snapshot_edits.push((snapshot, edits));
1542                    let (snapshot, edits) = writer.fold(to_fold, cx.as_ref());
1543                    snapshot_edits.push((snapshot, edits));
1544                }
1545            }
1546            snapshot_edits
1547        }
1548    }
1549}