fold_map.rs

   1use super::{
   2    buffer::{AnchorRangeExt, TextSummary},
   3    Anchor, Buffer, Point, ToOffset,
   4};
   5use buffer::HighlightId;
   6use gpui::{AppContext, ModelHandle};
   7use parking_lot::Mutex;
   8use std::{
   9    cmp::{self, Ordering},
  10    iter, mem,
  11    ops::Range,
  12    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  13};
  14use sum_tree::{self, Bias, Cursor, FilterCursor, SumTree};
  15
  16pub trait ToFoldPoint {
  17    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint;
  18}
  19
  20#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  21pub struct FoldPoint(pub super::Point);
  22
  23impl FoldPoint {
  24    pub fn new(row: u32, column: u32) -> Self {
  25        Self(super::Point::new(row, column))
  26    }
  27
  28    pub fn row(self) -> u32 {
  29        self.0.row
  30    }
  31
  32    pub fn column(self) -> u32 {
  33        self.0.column
  34    }
  35
  36    pub fn row_mut(&mut self) -> &mut u32 {
  37        &mut self.0.row
  38    }
  39
  40    #[cfg(test)]
  41    pub fn column_mut(&mut self) -> &mut u32 {
  42        &mut self.0.column
  43    }
  44
  45    pub fn to_buffer_point(&self, snapshot: &Snapshot) -> Point {
  46        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  47        cursor.seek(self, Bias::Right, &());
  48        let overshoot = self.0 - cursor.start().0 .0;
  49        cursor.start().1 + overshoot
  50    }
  51
  52    pub fn to_buffer_offset(&self, snapshot: &Snapshot) -> usize {
  53        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  54        cursor.seek(self, Bias::Right, &());
  55        let overshoot = self.0 - cursor.start().0 .0;
  56        snapshot
  57            .buffer_snapshot
  58            .to_offset(cursor.start().1 + overshoot)
  59    }
  60
  61    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  62        let mut cursor = snapshot
  63            .transforms
  64            .cursor::<(FoldPoint, TransformSummary)>();
  65        cursor.seek(self, Bias::Right, &());
  66        let overshoot = self.0 - cursor.start().1.output.lines;
  67        let mut offset = cursor.start().1.output.bytes;
  68        if !overshoot.is_zero() {
  69            let transform = cursor.item().expect("display point out of range");
  70            assert!(transform.output_text.is_none());
  71            let end_buffer_offset = snapshot
  72                .buffer_snapshot
  73                .to_offset(cursor.start().1.input.lines + overshoot);
  74            offset += end_buffer_offset - cursor.start().1.input.bytes;
  75        }
  76        FoldOffset(offset)
  77    }
  78}
  79
  80impl ToFoldPoint for Point {
  81    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  82        let mut cursor = snapshot.transforms.cursor::<(Point, FoldPoint)>();
  83        cursor.seek(self, Bias::Right, &());
  84        if cursor.item().map_or(false, |t| t.is_fold()) {
  85            if bias == Bias::Left || *self == cursor.start().0 {
  86                cursor.start().1
  87            } else {
  88                cursor.end(&()).1
  89            }
  90        } else {
  91            let overshoot = *self - cursor.start().0;
  92            FoldPoint(cmp::min(
  93                cursor.start().1 .0 + overshoot,
  94                cursor.end(&()).1 .0,
  95            ))
  96        }
  97    }
  98}
  99
 100pub struct FoldMapWriter<'a>(&'a mut FoldMap);
 101
 102impl<'a> FoldMapWriter<'a> {
 103    pub fn fold<T: ToOffset>(
 104        &mut self,
 105        ranges: impl IntoIterator<Item = Range<T>>,
 106        cx: &AppContext,
 107    ) -> (Snapshot, Vec<FoldEdit>) {
 108        let mut edits = Vec::new();
 109        let mut folds = Vec::new();
 110        let buffer = self.0.buffer.read(cx).snapshot();
 111        for range in ranges.into_iter() {
 112            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 113            if range.start != range.end {
 114                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 115                folds.push(fold);
 116                edits.push(buffer::Edit {
 117                    old_bytes: range.clone(),
 118                    new_bytes: range.clone(),
 119                    ..Default::default()
 120                });
 121            }
 122        }
 123
 124        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 125
 126        self.0.folds = {
 127            let mut new_tree = SumTree::new();
 128            let mut cursor = self.0.folds.cursor::<Fold>();
 129            for fold in folds {
 130                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 131                new_tree.push(fold, &buffer);
 132            }
 133            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 134            new_tree
 135        };
 136
 137        consolidate_buffer_edits(&mut edits);
 138        let edits = self.0.apply_edits(edits, cx);
 139        let snapshot = Snapshot {
 140            transforms: self.0.transforms.lock().clone(),
 141            folds: self.0.folds.clone(),
 142            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 143            version: self.0.version.load(SeqCst),
 144        };
 145        (snapshot, edits)
 146    }
 147
 148    pub fn unfold<T: ToOffset>(
 149        &mut self,
 150        ranges: impl IntoIterator<Item = Range<T>>,
 151        cx: &AppContext,
 152    ) -> (Snapshot, Vec<FoldEdit>) {
 153        let mut edits = Vec::new();
 154        let mut fold_ixs_to_delete = Vec::new();
 155        let buffer = self.0.buffer.read(cx).snapshot();
 156        for range in ranges.into_iter() {
 157            // Remove intersecting folds and add their ranges to edits that are passed to apply_edits.
 158            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 159            while let Some(fold) = folds_cursor.item() {
 160                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 161                edits.push(buffer::Edit {
 162                    old_bytes: offset_range.clone(),
 163                    new_bytes: offset_range,
 164                    ..Default::default()
 165                });
 166                fold_ixs_to_delete.push(*folds_cursor.start());
 167                folds_cursor.next(&buffer);
 168            }
 169        }
 170
 171        fold_ixs_to_delete.sort_unstable();
 172        fold_ixs_to_delete.dedup();
 173
 174        self.0.folds = {
 175            let mut cursor = self.0.folds.cursor::<usize>();
 176            let mut folds = SumTree::new();
 177            for fold_ix in fold_ixs_to_delete {
 178                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 179                cursor.next(&buffer);
 180            }
 181            folds.push_tree(cursor.suffix(&buffer), &buffer);
 182            folds
 183        };
 184
 185        consolidate_buffer_edits(&mut edits);
 186        let edits = self.0.apply_edits(edits, cx);
 187        let snapshot = Snapshot {
 188            transforms: self.0.transforms.lock().clone(),
 189            folds: self.0.folds.clone(),
 190            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 191            version: self.0.version.load(SeqCst),
 192        };
 193        (snapshot, edits)
 194    }
 195}
 196
 197pub struct FoldMap {
 198    buffer: ModelHandle<Buffer>,
 199    transforms: Mutex<SumTree<Transform>>,
 200    folds: SumTree<Fold>,
 201    last_sync: Mutex<SyncState>,
 202    version: AtomicUsize,
 203}
 204
 205#[derive(Clone)]
 206struct SyncState {
 207    version: clock::Global,
 208    parse_count: usize,
 209}
 210
 211impl FoldMap {
 212    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
 213        let buffer = buffer_handle.read(cx);
 214        let this = Self {
 215            buffer: buffer_handle,
 216            folds: Default::default(),
 217            transforms: Mutex::new(SumTree::from_item(
 218                Transform {
 219                    summary: TransformSummary {
 220                        input: buffer.text_summary(),
 221                        output: buffer.text_summary(),
 222                    },
 223                    output_text: None,
 224                },
 225                &(),
 226            )),
 227            last_sync: Mutex::new(SyncState {
 228                version: buffer.version(),
 229                parse_count: buffer.parse_count(),
 230            }),
 231            version: AtomicUsize::new(0),
 232        };
 233        let (snapshot, _) = this.read(cx);
 234        (this, snapshot)
 235    }
 236
 237    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 238        let edits = self.sync(cx);
 239        self.check_invariants(cx);
 240        let snapshot = Snapshot {
 241            transforms: self.transforms.lock().clone(),
 242            folds: self.folds.clone(),
 243            buffer_snapshot: self.buffer.read(cx).snapshot(),
 244            version: self.version.load(SeqCst),
 245        };
 246        (snapshot, edits)
 247    }
 248
 249    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 250        let (snapshot, edits) = self.read(cx);
 251        (FoldMapWriter(self), snapshot, edits)
 252    }
 253
 254    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 255        let buffer = self.buffer.read(cx);
 256        let last_sync = mem::replace(
 257            &mut *self.last_sync.lock(),
 258            SyncState {
 259                version: buffer.version(),
 260                parse_count: buffer.parse_count(),
 261            },
 262        );
 263        let edits = buffer
 264            .edits_since(last_sync.version)
 265            .map(Into::into)
 266            .collect::<Vec<_>>();
 267        if edits.is_empty() {
 268            if last_sync.parse_count != buffer.parse_count() {
 269                self.version.fetch_add(1, SeqCst);
 270            }
 271            Vec::new()
 272        } else {
 273            self.apply_edits(edits, cx)
 274        }
 275    }
 276
 277    fn check_invariants(&self, cx: &AppContext) {
 278        if cfg!(test) {
 279            let buffer = self.buffer.read(cx);
 280            assert_eq!(
 281                self.transforms.lock().summary().input.bytes,
 282                buffer.len(),
 283                "transform tree does not match buffer's length"
 284            );
 285        }
 286    }
 287
 288    fn apply_edits(&self, buffer_edits: Vec<buffer::Edit>, cx: &AppContext) -> Vec<FoldEdit> {
 289        let buffer = self.buffer.read(cx).snapshot();
 290        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 291
 292        let mut new_transforms = SumTree::new();
 293        let mut transforms = self.transforms.lock();
 294        let mut cursor = transforms.cursor::<usize>();
 295        cursor.seek(&0, Bias::Right, &());
 296
 297        while let Some(mut edit) = buffer_edits_iter.next() {
 298            new_transforms.push_tree(cursor.slice(&edit.old_bytes.start, Bias::Left, &()), &());
 299            edit.new_bytes.start -= edit.old_bytes.start - cursor.start();
 300            edit.old_bytes.start = *cursor.start();
 301
 302            cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 303            cursor.next(&());
 304
 305            let mut delta = edit.delta();
 306            loop {
 307                edit.old_bytes.end = *cursor.start();
 308
 309                if let Some(next_edit) = buffer_edits_iter.peek() {
 310                    if next_edit.old_bytes.start > edit.old_bytes.end {
 311                        break;
 312                    }
 313
 314                    let next_edit = buffer_edits_iter.next().unwrap();
 315                    delta += next_edit.delta();
 316
 317                    if next_edit.old_bytes.end >= edit.old_bytes.end {
 318                        edit.old_bytes.end = next_edit.old_bytes.end;
 319                        cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 320                        cursor.next(&());
 321                    }
 322                } else {
 323                    break;
 324                }
 325            }
 326
 327            edit.new_bytes.end =
 328                ((edit.new_bytes.start + edit.deleted_bytes()) as isize + delta) as usize;
 329
 330            let anchor = buffer.anchor_before(edit.new_bytes.start);
 331            let mut folds_cursor = self.folds.cursor::<Fold>();
 332            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 333
 334            let mut folds = iter::from_fn({
 335                let buffer = &buffer;
 336                move || {
 337                    let item = folds_cursor
 338                        .item()
 339                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 340                    folds_cursor.next(buffer);
 341                    item
 342                }
 343            })
 344            .peekable();
 345
 346            while folds
 347                .peek()
 348                .map_or(false, |fold| fold.start < edit.new_bytes.end)
 349            {
 350                let mut fold = folds.next().unwrap();
 351                let sum = new_transforms.summary();
 352
 353                assert!(fold.start >= sum.input.bytes);
 354
 355                while folds
 356                    .peek()
 357                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 358                {
 359                    let next_fold = folds.next().unwrap();
 360                    if next_fold.end > fold.end {
 361                        fold.end = next_fold.end;
 362                    }
 363                }
 364
 365                if fold.start > sum.input.bytes {
 366                    let text_summary = buffer.text_summary_for_range(sum.input.bytes..fold.start);
 367                    new_transforms.push(
 368                        Transform {
 369                            summary: TransformSummary {
 370                                output: text_summary.clone(),
 371                                input: text_summary,
 372                            },
 373                            output_text: None,
 374                        },
 375                        &(),
 376                    );
 377                }
 378
 379                if fold.end > fold.start {
 380                    let output_text = "";
 381                    let chars = output_text.chars().count() as u32;
 382                    let lines = super::Point::new(0, output_text.len() as u32);
 383                    new_transforms.push(
 384                        Transform {
 385                            summary: TransformSummary {
 386                                output: TextSummary {
 387                                    bytes: output_text.len(),
 388                                    lines,
 389                                    first_line_chars: chars,
 390                                    last_line_chars: chars,
 391                                    longest_row: 0,
 392                                    longest_row_chars: chars,
 393                                },
 394                                input: buffer.text_summary_for_range(fold.start..fold.end),
 395                            },
 396                            output_text: Some(output_text),
 397                        },
 398                        &(),
 399                    );
 400                }
 401            }
 402
 403            let sum = new_transforms.summary();
 404            if sum.input.bytes < edit.new_bytes.end {
 405                let text_summary =
 406                    buffer.text_summary_for_range(sum.input.bytes..edit.new_bytes.end);
 407                new_transforms.push(
 408                    Transform {
 409                        summary: TransformSummary {
 410                            output: text_summary.clone(),
 411                            input: text_summary,
 412                        },
 413                        output_text: None,
 414                    },
 415                    &(),
 416                );
 417            }
 418        }
 419
 420        new_transforms.push_tree(cursor.suffix(&()), &());
 421        if new_transforms.is_empty() {
 422            let text_summary = buffer.text_summary();
 423            new_transforms.push(
 424                Transform {
 425                    summary: TransformSummary {
 426                        output: text_summary.clone(),
 427                        input: text_summary,
 428                    },
 429                    output_text: None,
 430                },
 431                &(),
 432            );
 433        }
 434
 435        drop(cursor);
 436
 437        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 438        {
 439            let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 440            let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 441
 442            for mut edit in buffer_edits {
 443                old_transforms.seek(&edit.old_bytes.start, Bias::Left, &());
 444                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 445                    edit.old_bytes.start = old_transforms.start().0;
 446                }
 447                let old_start =
 448                    old_transforms.start().1 .0 + (edit.old_bytes.start - old_transforms.start().0);
 449
 450                old_transforms.seek_forward(&edit.old_bytes.end, Bias::Right, &());
 451                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 452                    old_transforms.next(&());
 453                    edit.old_bytes.end = old_transforms.start().0;
 454                }
 455                let old_end =
 456                    old_transforms.start().1 .0 + (edit.old_bytes.end - old_transforms.start().0);
 457
 458                new_transforms.seek(&edit.new_bytes.start, Bias::Left, &());
 459                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 460                    edit.new_bytes.start = new_transforms.start().0;
 461                }
 462                let new_start =
 463                    new_transforms.start().1 .0 + (edit.new_bytes.start - new_transforms.start().0);
 464
 465                new_transforms.seek_forward(&edit.new_bytes.end, Bias::Right, &());
 466                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 467                    new_transforms.next(&());
 468                    edit.new_bytes.end = new_transforms.start().0;
 469                }
 470                let new_end =
 471                    new_transforms.start().1 .0 + (edit.new_bytes.end - new_transforms.start().0);
 472
 473                fold_edits.push(FoldEdit {
 474                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 475                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 476                });
 477            }
 478
 479            consolidate_fold_edits(&mut fold_edits);
 480        }
 481
 482        *transforms = new_transforms;
 483        self.version.fetch_add(1, SeqCst);
 484        fold_edits
 485    }
 486}
 487
 488#[derive(Clone)]
 489pub struct Snapshot {
 490    transforms: SumTree<Transform>,
 491    folds: SumTree<Fold>,
 492    buffer_snapshot: buffer::Snapshot,
 493    pub version: usize,
 494}
 495
 496impl Snapshot {
 497    #[cfg(test)]
 498    pub fn text(&self) -> String {
 499        self.chunks_at(FoldOffset(0)).collect()
 500    }
 501
 502    #[cfg(test)]
 503    pub fn fold_count(&self) -> usize {
 504        self.folds.items(&self.buffer_snapshot).len()
 505    }
 506
 507    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 508        let mut summary = TextSummary::default();
 509
 510        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 511        cursor.seek(&range.start, Bias::Right, &());
 512        if let Some(transform) = cursor.item() {
 513            let start_in_transform = range.start.0 - cursor.start().0 .0;
 514            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 515            if let Some(output_text) = transform.output_text {
 516                summary = TextSummary::from(
 517                    &output_text
 518                        [start_in_transform.column as usize..end_in_transform.column as usize],
 519                );
 520            } else {
 521                let buffer_start = cursor.start().1 + start_in_transform;
 522                let buffer_end = cursor.start().1 + end_in_transform;
 523                summary = self
 524                    .buffer_snapshot
 525                    .text_summary_for_range(buffer_start..buffer_end);
 526            }
 527        }
 528
 529        if range.end > cursor.end(&()).0 {
 530            cursor.next(&());
 531            summary += &cursor
 532                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 533                .output;
 534            if let Some(transform) = cursor.item() {
 535                let end_in_transform = range.end.0 - cursor.start().0 .0;
 536                if let Some(output_text) = transform.output_text {
 537                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 538                } else {
 539                    let buffer_start = cursor.start().1;
 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
 548        summary
 549    }
 550
 551    #[cfg(test)]
 552    pub fn len(&self) -> FoldOffset {
 553        FoldOffset(self.transforms.summary().output.bytes)
 554    }
 555
 556    #[cfg(test)]
 557    pub fn line_len(&self, row: u32) -> u32 {
 558        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 559        let line_end = if row >= self.max_point().row() {
 560            self.len().0
 561        } else {
 562            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 563        };
 564        (line_end - line_start) as u32
 565    }
 566
 567    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 568        if start_row > self.transforms.summary().output.lines.row {
 569            panic!("invalid display row {}", start_row);
 570        }
 571
 572        let fold_point = FoldPoint::new(start_row, 0);
 573        let mut cursor = self.transforms.cursor();
 574        cursor.seek(&fold_point, Bias::Left, &());
 575        BufferRows { fold_point, cursor }
 576    }
 577
 578    pub fn max_point(&self) -> FoldPoint {
 579        FoldPoint(self.transforms.summary().output.lines)
 580    }
 581
 582    #[cfg(test)]
 583    pub fn longest_row(&self) -> u32 {
 584        self.transforms.summary().output.longest_row
 585    }
 586
 587    pub fn folds_in_range<'a, T>(
 588        &'a self,
 589        range: Range<T>,
 590    ) -> impl Iterator<Item = &'a Range<Anchor>>
 591    where
 592        T: ToOffset,
 593    {
 594        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 595        iter::from_fn(move || {
 596            let item = folds.item().map(|f| &f.0);
 597            folds.next(&self.buffer_snapshot);
 598            item
 599        })
 600    }
 601
 602    pub fn intersects_fold<T>(&self, offset: T) -> bool
 603    where
 604        T: ToOffset,
 605    {
 606        let offset = offset.to_offset(&self.buffer_snapshot);
 607        let mut cursor = self.transforms.cursor::<usize>();
 608        cursor.seek(&offset, Bias::Right, &());
 609        cursor.item().map_or(false, |t| t.output_text.is_some())
 610    }
 611
 612    pub fn is_line_folded(&self, output_row: u32) -> bool {
 613        let mut cursor = self.transforms.cursor::<FoldPoint>();
 614        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 615        while let Some(transform) = cursor.item() {
 616            if transform.output_text.is_some() {
 617                return true;
 618            }
 619            if cursor.end(&()).row() == output_row {
 620                cursor.next(&())
 621            } else {
 622                break;
 623            }
 624        }
 625        false
 626    }
 627
 628    pub fn chunks_at(&self, offset: FoldOffset) -> Chunks {
 629        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 630        transform_cursor.seek(&offset, Bias::Right, &());
 631        let overshoot = offset.0 - transform_cursor.start().0 .0;
 632        let buffer_offset = transform_cursor.start().1 + overshoot;
 633        Chunks {
 634            transform_cursor,
 635            buffer_offset,
 636            buffer_chunks: self
 637                .buffer_snapshot
 638                .text_for_range(buffer_offset..self.buffer_snapshot.len()),
 639        }
 640    }
 641
 642    pub fn highlighted_chunks(&mut self, range: Range<FoldOffset>) -> HighlightedChunks {
 643        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 644
 645        transform_cursor.seek(&range.end, Bias::Right, &());
 646        let overshoot = range.end.0 - transform_cursor.start().0 .0;
 647        let buffer_end = transform_cursor.start().1 + overshoot;
 648
 649        transform_cursor.seek(&range.start, Bias::Right, &());
 650        let overshoot = range.start.0 - transform_cursor.start().0 .0;
 651        let buffer_start = transform_cursor.start().1 + overshoot;
 652
 653        HighlightedChunks {
 654            transform_cursor,
 655            buffer_offset: buffer_start,
 656            buffer_chunks: self
 657                .buffer_snapshot
 658                .highlighted_text_for_range(buffer_start..buffer_end),
 659            buffer_chunk: None,
 660        }
 661    }
 662
 663    pub fn chars_at<'a>(&'a self, point: FoldPoint) -> impl Iterator<Item = char> + 'a {
 664        let offset = point.to_offset(self);
 665        self.chunks_at(offset).flat_map(str::chars)
 666    }
 667
 668    #[cfg(test)]
 669    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 670        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 671        cursor.seek(&offset, Bias::Right, &());
 672        if let Some(transform) = cursor.item() {
 673            let transform_start = cursor.start().0 .0;
 674            if transform.output_text.is_some() {
 675                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 676                    FoldOffset(transform_start)
 677                } else {
 678                    FoldOffset(cursor.end(&()).0 .0)
 679                }
 680            } else {
 681                let overshoot = offset.0 - transform_start;
 682                let buffer_offset = cursor.start().1 + overshoot;
 683                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 684                FoldOffset(
 685                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 686                        as usize,
 687                )
 688            }
 689        } else {
 690            FoldOffset(self.transforms.summary().output.bytes)
 691        }
 692    }
 693
 694    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 695        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 696        cursor.seek(&point, Bias::Right, &());
 697        if let Some(transform) = cursor.item() {
 698            let transform_start = cursor.start().0 .0;
 699            if transform.output_text.is_some() {
 700                if point.0 == transform_start || matches!(bias, Bias::Left) {
 701                    FoldPoint(transform_start)
 702                } else {
 703                    FoldPoint(cursor.end(&()).0 .0)
 704                }
 705            } else {
 706                let overshoot = point.0 - transform_start;
 707                let buffer_position = cursor.start().1 + overshoot;
 708                let clipped_buffer_position =
 709                    self.buffer_snapshot.clip_point(buffer_position, bias);
 710                FoldPoint::new(
 711                    point.row(),
 712                    ((point.column() as i32) + clipped_buffer_position.column as i32
 713                        - buffer_position.column as i32) as u32,
 714                )
 715            }
 716        } else {
 717            FoldPoint(self.transforms.summary().output.lines)
 718        }
 719    }
 720}
 721
 722fn intersecting_folds<'a, T>(
 723    buffer: &'a buffer::Snapshot,
 724    folds: &'a SumTree<Fold>,
 725    range: Range<T>,
 726    inclusive: bool,
 727) -> FilterCursor<'a, impl 'a + Fn(&FoldSummary) -> bool, Fold, usize>
 728where
 729    T: ToOffset,
 730{
 731    let start = buffer.anchor_before(range.start.to_offset(buffer));
 732    let end = buffer.anchor_after(range.end.to_offset(buffer));
 733    folds.filter::<_, usize>(
 734        move |summary| {
 735            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 736            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 737
 738            if inclusive {
 739                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 740            } else {
 741                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 742            }
 743        },
 744        buffer,
 745    )
 746}
 747
 748fn consolidate_buffer_edits(edits: &mut Vec<buffer::Edit>) {
 749    edits.sort_unstable_by(|a, b| {
 750        a.old_bytes
 751            .start
 752            .cmp(&b.old_bytes.start)
 753            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 754    });
 755
 756    let mut i = 1;
 757    while i < edits.len() {
 758        let edit = edits[i].clone();
 759        let prev_edit = &mut edits[i - 1];
 760        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 761            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 762            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 763            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 764            edits.remove(i);
 765            continue;
 766        }
 767        i += 1;
 768    }
 769}
 770
 771fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 772    edits.sort_unstable_by(|a, b| {
 773        a.old_bytes
 774            .start
 775            .cmp(&b.old_bytes.start)
 776            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 777    });
 778
 779    let mut i = 1;
 780    while i < edits.len() {
 781        let edit = edits[i].clone();
 782        let prev_edit = &mut edits[i - 1];
 783        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 784            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 785            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 786            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 787            edits.remove(i);
 788            continue;
 789        }
 790        i += 1;
 791    }
 792}
 793
 794#[derive(Clone, Debug, Default, Eq, PartialEq)]
 795struct Transform {
 796    summary: TransformSummary,
 797    output_text: Option<&'static str>,
 798}
 799
 800impl Transform {
 801    fn is_fold(&self) -> bool {
 802        self.output_text.is_some()
 803    }
 804}
 805
 806#[derive(Clone, Debug, Default, Eq, PartialEq)]
 807struct TransformSummary {
 808    output: TextSummary,
 809    input: TextSummary,
 810}
 811
 812impl sum_tree::Item for Transform {
 813    type Summary = TransformSummary;
 814
 815    fn summary(&self) -> Self::Summary {
 816        self.summary.clone()
 817    }
 818}
 819
 820impl sum_tree::Summary for TransformSummary {
 821    type Context = ();
 822
 823    fn add_summary(&mut self, other: &Self, _: &()) {
 824        self.input += &other.input;
 825        self.output += &other.output;
 826    }
 827}
 828
 829#[derive(Clone, Debug)]
 830struct Fold(Range<Anchor>);
 831
 832impl Default for Fold {
 833    fn default() -> Self {
 834        Self(Anchor::min()..Anchor::max())
 835    }
 836}
 837
 838impl sum_tree::Item for Fold {
 839    type Summary = FoldSummary;
 840
 841    fn summary(&self) -> Self::Summary {
 842        FoldSummary {
 843            start: self.0.start.clone(),
 844            end: self.0.end.clone(),
 845            min_start: self.0.start.clone(),
 846            max_end: self.0.end.clone(),
 847            count: 1,
 848        }
 849    }
 850}
 851
 852#[derive(Clone, Debug)]
 853struct FoldSummary {
 854    start: Anchor,
 855    end: Anchor,
 856    min_start: Anchor,
 857    max_end: Anchor,
 858    count: usize,
 859}
 860
 861impl Default for FoldSummary {
 862    fn default() -> Self {
 863        Self {
 864            start: Anchor::min(),
 865            end: Anchor::max(),
 866            min_start: Anchor::max(),
 867            max_end: Anchor::min(),
 868            count: 0,
 869        }
 870    }
 871}
 872
 873impl sum_tree::Summary for FoldSummary {
 874    type Context = buffer::Snapshot;
 875
 876    fn add_summary(&mut self, other: &Self, buffer: &buffer::Snapshot) {
 877        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 878            self.min_start = other.min_start.clone();
 879        }
 880        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 881            self.max_end = other.max_end.clone();
 882        }
 883
 884        #[cfg(debug_assertions)]
 885        {
 886            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 887            assert!(start_comparison <= Ordering::Equal);
 888            if start_comparison == Ordering::Equal {
 889                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 890            }
 891        }
 892
 893        self.start = other.start.clone();
 894        self.end = other.end.clone();
 895        self.count += other.count;
 896    }
 897}
 898
 899impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 900    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 901        self.0.start = summary.start.clone();
 902        self.0.end = summary.end.clone();
 903    }
 904}
 905
 906impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 907    fn cmp(&self, other: &Self, buffer: &buffer::Snapshot) -> Ordering {
 908        self.0.cmp(&other.0, buffer).unwrap()
 909    }
 910}
 911
 912impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 913    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 914        *self += summary.count;
 915    }
 916}
 917
 918pub struct BufferRows<'a> {
 919    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 920    fold_point: FoldPoint,
 921}
 922
 923impl<'a> Iterator for BufferRows<'a> {
 924    type Item = u32;
 925
 926    fn next(&mut self) -> Option<Self::Item> {
 927        while self.fold_point > self.cursor.end(&()).0 {
 928            self.cursor.next(&());
 929            if self.cursor.item().is_none() {
 930                // TODO: Return a bool from next?
 931                break;
 932            }
 933        }
 934
 935        if self.cursor.item().is_some() {
 936            let overshoot = self.fold_point.0 - self.cursor.start().0 .0;
 937            let buffer_point = self.cursor.start().1 + overshoot;
 938            *self.fold_point.row_mut() += 1;
 939            Some(buffer_point.row)
 940        } else {
 941            None
 942        }
 943    }
 944}
 945
 946pub struct Chunks<'a> {
 947    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 948    buffer_chunks: buffer::Chunks<'a>,
 949    buffer_offset: usize,
 950}
 951
 952impl<'a> Iterator for Chunks<'a> {
 953    type Item = &'a str;
 954
 955    fn next(&mut self) -> Option<Self::Item> {
 956        let transform = if let Some(item) = self.transform_cursor.item() {
 957            item
 958        } else {
 959            return None;
 960        };
 961
 962        // If we're in a fold, then return the fold's display text and
 963        // advance the transform and buffer cursors to the end of the fold.
 964        if let Some(output_text) = transform.output_text {
 965            self.buffer_offset += transform.summary.input.bytes;
 966            self.buffer_chunks.seek(self.buffer_offset);
 967
 968            while self.buffer_offset >= self.transform_cursor.end(&()).1
 969                && self.transform_cursor.item().is_some()
 970            {
 971                self.transform_cursor.next(&());
 972            }
 973
 974            return Some(output_text);
 975        }
 976
 977        // Otherwise, take a chunk from the buffer's text.
 978        if let Some(mut chunk) = self.buffer_chunks.peek() {
 979            let offset_in_chunk = self.buffer_offset - self.buffer_chunks.offset();
 980            chunk = &chunk[offset_in_chunk..];
 981
 982            // Truncate the chunk so that it ends at the next fold.
 983            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
 984            if chunk.len() >= region_end {
 985                chunk = &chunk[0..region_end];
 986                self.transform_cursor.next(&());
 987            } else {
 988                self.buffer_chunks.next();
 989            }
 990
 991            self.buffer_offset += chunk.len();
 992            return Some(chunk);
 993        }
 994
 995        None
 996    }
 997}
 998
 999pub struct HighlightedChunks<'a> {
1000    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
1001    buffer_chunks: buffer::HighlightedChunks<'a>,
1002    buffer_chunk: Option<(usize, &'a str, HighlightId)>,
1003    buffer_offset: usize,
1004}
1005
1006impl<'a> Iterator for HighlightedChunks<'a> {
1007    type Item = (&'a str, HighlightId);
1008
1009    fn next(&mut self) -> Option<Self::Item> {
1010        let transform = if let Some(item) = self.transform_cursor.item() {
1011            item
1012        } else {
1013            return None;
1014        };
1015
1016        // If we're in a fold, then return the fold's display text and
1017        // advance the transform and buffer cursors to the end of the fold.
1018        if let Some(output_text) = transform.output_text {
1019            self.buffer_chunk.take();
1020            self.buffer_offset += transform.summary.input.bytes;
1021            self.buffer_chunks.seek(self.buffer_offset);
1022
1023            while self.buffer_offset >= self.transform_cursor.end(&()).1
1024                && self.transform_cursor.item().is_some()
1025            {
1026                self.transform_cursor.next(&());
1027            }
1028
1029            return Some((output_text, HighlightId::default()));
1030        }
1031
1032        // Retrieve a chunk from the current location in the buffer.
1033        if self.buffer_chunk.is_none() {
1034            let chunk_offset = self.buffer_chunks.offset();
1035            self.buffer_chunk = self
1036                .buffer_chunks
1037                .next()
1038                .map(|(chunk, capture_ix)| (chunk_offset, chunk, capture_ix));
1039        }
1040
1041        // Otherwise, take a chunk from the buffer's text.
1042        if let Some((chunk_offset, mut chunk, capture_ix)) = self.buffer_chunk {
1043            let offset_in_chunk = self.buffer_offset - chunk_offset;
1044            chunk = &chunk[offset_in_chunk..];
1045
1046            // Truncate the chunk so that it ends at the next fold.
1047            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
1048            if chunk.len() >= region_end {
1049                chunk = &chunk[0..region_end];
1050                self.transform_cursor.next(&());
1051            } else {
1052                self.buffer_chunk.take();
1053            }
1054
1055            self.buffer_offset += chunk.len();
1056            return Some((chunk, capture_ix));
1057        }
1058
1059        None
1060    }
1061}
1062
1063impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1064    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1065        self.0 += &summary.output.lines;
1066    }
1067}
1068
1069#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1070pub struct FoldOffset(pub usize);
1071
1072impl FoldOffset {
1073    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1074        let mut cursor = snapshot
1075            .transforms
1076            .cursor::<(FoldOffset, TransformSummary)>();
1077        cursor.seek(self, Bias::Right, &());
1078        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1079            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1080        } else {
1081            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1082            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1083            buffer_point - cursor.start().1.input.lines
1084        };
1085        FoldPoint(cursor.start().1.output.lines + overshoot)
1086    }
1087}
1088
1089impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1090    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1091        self.0 += &summary.output.bytes;
1092    }
1093}
1094
1095impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1096    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1097        *self += &summary.input.lines;
1098    }
1099}
1100
1101impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1102    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1103        *self += &summary.input.bytes;
1104    }
1105}
1106
1107#[derive(Clone, Debug, PartialEq, Eq)]
1108pub struct FoldEdit {
1109    pub old_bytes: Range<FoldOffset>,
1110    pub new_bytes: Range<FoldOffset>,
1111}
1112
1113#[cfg(test)]
1114impl FoldEdit {
1115    pub fn delta(&self) -> isize {
1116        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1117    }
1118
1119    pub fn deleted_bytes(&self) -> usize {
1120        self.old_bytes.end.0 - self.old_bytes.start.0
1121    }
1122
1123    pub fn inserted_bytes(&self) -> usize {
1124        self.new_bytes.end.0 - self.new_bytes.start.0
1125    }
1126}
1127
1128#[cfg(test)]
1129mod tests {
1130    use super::*;
1131    use crate::{test::sample_text, ToPoint};
1132    use buffer::RandomCharIter;
1133    use rand::prelude::*;
1134    use std::{env, mem};
1135    use Bias::{Left, Right};
1136
1137    #[gpui::test]
1138    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1139        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1140        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1141
1142        let (mut writer, _, _) = map.write(cx.as_ref());
1143        let (snapshot2, edits) = writer.fold(
1144            vec![
1145                Point::new(0, 2)..Point::new(2, 2),
1146                Point::new(2, 4)..Point::new(4, 1),
1147            ],
1148            cx.as_ref(),
1149        );
1150        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1151        assert_eq!(
1152            edits,
1153            &[
1154                FoldEdit {
1155                    old_bytes: FoldOffset(2)..FoldOffset(16),
1156                    new_bytes: FoldOffset(2)..FoldOffset(5),
1157                },
1158                FoldEdit {
1159                    old_bytes: FoldOffset(18)..FoldOffset(29),
1160                    new_bytes: FoldOffset(7)..FoldOffset(10)
1161                },
1162            ]
1163        );
1164
1165        buffer.update(cx, |buffer, cx| {
1166            buffer.edit(
1167                vec![
1168                    Point::new(0, 0)..Point::new(0, 1),
1169                    Point::new(2, 3)..Point::new(2, 3),
1170                ],
1171                "123",
1172                cx,
1173            );
1174        });
1175        let (snapshot3, edits) = map.read(cx.as_ref());
1176        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1177        assert_eq!(
1178            edits,
1179            &[
1180                FoldEdit {
1181                    old_bytes: FoldOffset(0)..FoldOffset(1),
1182                    new_bytes: FoldOffset(0)..FoldOffset(3),
1183                },
1184                FoldEdit {
1185                    old_bytes: FoldOffset(6)..FoldOffset(6),
1186                    new_bytes: FoldOffset(8)..FoldOffset(11),
1187                },
1188            ]
1189        );
1190
1191        buffer.update(cx, |buffer, cx| {
1192            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx)
1193        });
1194        let (snapshot4, _) = map.read(cx.as_ref());
1195        assert_eq!(snapshot4.text(), "123a…c123456eee");
1196
1197        let (mut writer, _, _) = map.write(cx.as_ref());
1198        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), cx.as_ref());
1199        let (snapshot5, _) = map.read(cx.as_ref());
1200        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1201    }
1202
1203    #[gpui::test]
1204    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1205        let buffer = cx.add_model(|cx| Buffer::new(0, "abcdefghijkl", cx));
1206
1207        {
1208            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1209
1210            let (mut writer, _, _) = map.write(cx.as_ref());
1211            writer.fold(vec![5..8], cx.as_ref());
1212            let (snapshot, _) = map.read(cx.as_ref());
1213            assert_eq!(snapshot.text(), "abcde…ijkl");
1214
1215            // Create an fold adjacent to the start of the first fold.
1216            let (mut writer, _, _) = map.write(cx.as_ref());
1217            writer.fold(vec![0..1, 2..5], cx.as_ref());
1218            let (snapshot, _) = map.read(cx.as_ref());
1219            assert_eq!(snapshot.text(), "…b…ijkl");
1220
1221            // Create an fold adjacent to the end of the first fold.
1222            let (mut writer, _, _) = map.write(cx.as_ref());
1223            writer.fold(vec![11..11, 8..10], cx.as_ref());
1224            let (snapshot, _) = map.read(cx.as_ref());
1225            assert_eq!(snapshot.text(), "…b…kl");
1226        }
1227
1228        {
1229            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1230
1231            // Create two adjacent folds.
1232            let (mut writer, _, _) = map.write(cx.as_ref());
1233            writer.fold(vec![0..2, 2..5], cx.as_ref());
1234            let (snapshot, _) = map.read(cx.as_ref());
1235            assert_eq!(snapshot.text(), "…fghijkl");
1236
1237            // Edit within one of the folds.
1238            buffer.update(cx, |buffer, cx| buffer.edit(vec![0..1], "12345", cx));
1239            let (snapshot, _) = map.read(cx.as_ref());
1240            assert_eq!(snapshot.text(), "12345…fghijkl");
1241        }
1242    }
1243
1244    #[gpui::test]
1245    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1246        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1247        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1248        let (mut writer, _, _) = map.write(cx.as_ref());
1249        writer.fold(
1250            vec![
1251                Point::new(0, 2)..Point::new(2, 2),
1252                Point::new(0, 4)..Point::new(1, 0),
1253                Point::new(1, 2)..Point::new(3, 2),
1254                Point::new(3, 1)..Point::new(4, 1),
1255            ],
1256            cx.as_ref(),
1257        );
1258        let (snapshot, _) = map.read(cx.as_ref());
1259        assert_eq!(snapshot.text(), "aa…eeeee");
1260    }
1261
1262    #[gpui::test]
1263    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1264        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1265        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1266
1267        let (mut writer, _, _) = map.write(cx.as_ref());
1268        writer.fold(
1269            vec![
1270                Point::new(0, 2)..Point::new(2, 2),
1271                Point::new(3, 1)..Point::new(4, 1),
1272            ],
1273            cx.as_ref(),
1274        );
1275        let (snapshot, _) = map.read(cx.as_ref());
1276        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1277
1278        buffer.update(cx, |buffer, cx| {
1279            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx)
1280        });
1281        let (snapshot, _) = map.read(cx.as_ref());
1282        assert_eq!(snapshot.text(), "aa…eeeee");
1283    }
1284
1285    #[gpui::test]
1286    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1287        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1288        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1289        let buffer = buffer.read(cx);
1290
1291        let (mut writer, _, _) = map.write(cx.as_ref());
1292        writer.fold(
1293            vec![
1294                Point::new(0, 2)..Point::new(2, 2),
1295                Point::new(0, 4)..Point::new(1, 0),
1296                Point::new(1, 2)..Point::new(3, 2),
1297                Point::new(3, 1)..Point::new(4, 1),
1298            ],
1299            cx.as_ref(),
1300        );
1301        let (snapshot, _) = map.read(cx.as_ref());
1302        let fold_ranges = snapshot
1303            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1304            .map(|fold| fold.start.to_point(buffer)..fold.end.to_point(buffer))
1305            .collect::<Vec<_>>();
1306        assert_eq!(
1307            fold_ranges,
1308            vec![
1309                Point::new(0, 2)..Point::new(2, 2),
1310                Point::new(1, 2)..Point::new(3, 2)
1311            ]
1312        );
1313    }
1314
1315    #[gpui::test(iterations = 100)]
1316    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1317        let operations = env::var("OPERATIONS")
1318            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1319            .unwrap_or(10);
1320
1321        let buffer = cx.add_model(|cx| {
1322            let len = rng.gen_range(0..10);
1323            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1324            Buffer::new(0, text, cx)
1325        });
1326        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1327
1328        let (mut initial_snapshot, _) = map.read(cx.as_ref());
1329        let mut snapshot_edits = Vec::new();
1330
1331        for _ in 0..operations {
1332            log::info!("text: {:?}", buffer.read(cx).text());
1333            match rng.gen_range(0..=100) {
1334                0..=59 => {
1335                    snapshot_edits.extend(map.randomly_mutate(&mut rng, cx.as_ref()));
1336                }
1337                _ => {
1338                    let edits = buffer.update(cx, |buffer, cx| {
1339                        let start_version = buffer.version.clone();
1340                        let edit_count = rng.gen_range(1..=5);
1341                        buffer.randomly_edit(&mut rng, edit_count, cx);
1342                        buffer.edits_since(start_version).collect::<Vec<_>>()
1343                    });
1344                    log::info!("editing {:?}", edits);
1345                }
1346            }
1347
1348            let buffer = map.buffer.read(cx).snapshot();
1349            let mut expected_text: String = buffer.text().into();
1350            let mut expected_buffer_rows = Vec::new();
1351            let mut next_row = buffer.max_point().row;
1352            for fold_range in map.merged_fold_ranges(cx.as_ref()).into_iter().rev() {
1353                let fold_start = buffer.point_for_offset(fold_range.start).unwrap();
1354                let fold_end = buffer.point_for_offset(fold_range.end).unwrap();
1355                expected_buffer_rows.extend((fold_end.row + 1..=next_row).rev());
1356                next_row = fold_start.row;
1357
1358                expected_text.replace_range(fold_range.start..fold_range.end, "");
1359            }
1360            expected_buffer_rows.extend((0..=next_row).rev());
1361            expected_buffer_rows.reverse();
1362
1363            let (snapshot, edits) = map.read(cx.as_ref());
1364            assert_eq!(snapshot.text(), expected_text);
1365            snapshot_edits.push((snapshot.clone(), edits));
1366
1367            for (output_row, line) in expected_text.lines().enumerate() {
1368                let line_len = snapshot.line_len(output_row as u32);
1369                assert_eq!(line_len, line.len() as u32);
1370            }
1371
1372            let longest_row = snapshot.longest_row();
1373            let longest_char_column = expected_text
1374                .split('\n')
1375                .nth(longest_row as usize)
1376                .unwrap()
1377                .chars()
1378                .count();
1379            let mut fold_point = FoldPoint::new(0, 0);
1380            let mut fold_offset = FoldOffset(0);
1381            let mut char_column = 0;
1382            for c in expected_text.chars() {
1383                let buffer_point = fold_point.to_buffer_point(&snapshot);
1384                let buffer_offset = buffer_point.to_offset(&buffer);
1385                assert_eq!(
1386                    buffer_point.to_fold_point(&snapshot, Right),
1387                    fold_point,
1388                    "{:?} -> fold point",
1389                    buffer_point,
1390                );
1391                assert_eq!(
1392                    fold_point.to_buffer_offset(&snapshot),
1393                    buffer_offset,
1394                    "fold_point.to_buffer_offset({:?})",
1395                    fold_point,
1396                );
1397                assert_eq!(
1398                    fold_point.to_offset(&snapshot),
1399                    fold_offset,
1400                    "fold_point.to_offset({:?})",
1401                    fold_point,
1402                );
1403
1404                if c == '\n' {
1405                    *fold_point.row_mut() += 1;
1406                    *fold_point.column_mut() = 0;
1407                    char_column = 0;
1408                } else {
1409                    *fold_point.column_mut() += c.len_utf8() as u32;
1410                    char_column += 1;
1411                }
1412                fold_offset.0 += c.len_utf8();
1413                if char_column > longest_char_column {
1414                    panic!(
1415                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1416                        longest_row,
1417                        longest_char_column,
1418                        fold_point.row(),
1419                        char_column
1420                    );
1421                }
1422            }
1423
1424            for _ in 0..5 {
1425                let offset = snapshot
1426                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1427                assert_eq!(
1428                    snapshot.chunks_at(offset).collect::<String>(),
1429                    &expected_text[offset.0..],
1430                );
1431            }
1432
1433            for (idx, buffer_row) in expected_buffer_rows.iter().enumerate() {
1434                let fold_row = Point::new(*buffer_row, 0)
1435                    .to_fold_point(&snapshot, Right)
1436                    .row();
1437                assert_eq!(
1438                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1439                    expected_buffer_rows[idx..],
1440                );
1441            }
1442
1443            for fold_range in map.merged_fold_ranges(cx.as_ref()) {
1444                let fold_point = fold_range
1445                    .start
1446                    .to_point(&buffer)
1447                    .to_fold_point(&snapshot, Right);
1448                assert!(snapshot.is_line_folded(fold_point.row()));
1449            }
1450
1451            for _ in 0..5 {
1452                let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1453                let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1454                let expected_folds = map
1455                    .folds
1456                    .items(&buffer)
1457                    .into_iter()
1458                    .filter(|fold| {
1459                        let start = buffer.anchor_before(start);
1460                        let end = buffer.anchor_after(end);
1461                        start.cmp(&fold.0.end, &buffer).unwrap() == Ordering::Less
1462                            && end.cmp(&fold.0.start, &buffer).unwrap() == Ordering::Greater
1463                    })
1464                    .map(|fold| fold.0)
1465                    .collect::<Vec<_>>();
1466
1467                assert_eq!(
1468                    snapshot
1469                        .folds_in_range(start..end)
1470                        .cloned()
1471                        .collect::<Vec<_>>(),
1472                    expected_folds
1473                );
1474            }
1475
1476            let text = snapshot.text();
1477            for _ in 0..5 {
1478                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1479                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1480                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1481                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1482                let mut start =
1483                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1484                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1485                if start > end {
1486                    mem::swap(&mut start, &mut end);
1487                }
1488
1489                let lines = start..end;
1490                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1491                assert_eq!(
1492                    snapshot.text_summary_for_range(lines),
1493                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1494                )
1495            }
1496
1497            let mut text = initial_snapshot.text();
1498            for (snapshot, edits) in snapshot_edits.drain(..) {
1499                let new_text = snapshot.text();
1500                let mut delta = 0isize;
1501                for edit in edits {
1502                    let old_bytes = ((edit.old_bytes.start.0 as isize) + delta) as usize
1503                        ..((edit.old_bytes.end.0 as isize) + delta) as usize;
1504                    let new_bytes = edit.new_bytes.start.0..edit.new_bytes.end.0;
1505                    delta += edit.delta();
1506                    text.replace_range(old_bytes, &new_text[new_bytes]);
1507                }
1508
1509                assert_eq!(text, new_text);
1510                initial_snapshot = snapshot;
1511            }
1512        }
1513    }
1514
1515    #[gpui::test]
1516    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1517        let text = sample_text(6, 6) + "\n";
1518        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1519
1520        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1521
1522        let (mut writer, _, _) = map.write(cx.as_ref());
1523        writer.fold(
1524            vec![
1525                Point::new(0, 2)..Point::new(2, 2),
1526                Point::new(3, 1)..Point::new(4, 1),
1527            ],
1528            cx.as_ref(),
1529        );
1530
1531        let (snapshot, _) = map.read(cx.as_ref());
1532        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1533        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), [0, 3, 5, 6]);
1534        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [6]);
1535    }
1536
1537    impl FoldMap {
1538        fn merged_fold_ranges(&self, cx: &AppContext) -> Vec<Range<usize>> {
1539            let buffer = self.buffer.read(cx).snapshot();
1540            let mut folds = self.folds.items(&buffer);
1541            // Ensure sorting doesn't change how folds get merged and displayed.
1542            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1543            let mut fold_ranges = folds
1544                .iter()
1545                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1546                .peekable();
1547
1548            let mut merged_ranges = Vec::new();
1549            while let Some(mut fold_range) = fold_ranges.next() {
1550                while let Some(next_range) = fold_ranges.peek() {
1551                    if fold_range.end >= next_range.start {
1552                        if next_range.end > fold_range.end {
1553                            fold_range.end = next_range.end;
1554                        }
1555                        fold_ranges.next();
1556                    } else {
1557                        break;
1558                    }
1559                }
1560                if fold_range.end > fold_range.start {
1561                    merged_ranges.push(fold_range);
1562                }
1563            }
1564            merged_ranges
1565        }
1566
1567        pub fn randomly_mutate(
1568            &mut self,
1569            rng: &mut impl Rng,
1570            cx: &AppContext,
1571        ) -> Vec<(Snapshot, Vec<FoldEdit>)> {
1572            let mut snapshot_edits = Vec::new();
1573            match rng.gen_range(0..=100) {
1574                0..=39 if !self.folds.is_empty() => {
1575                    let buffer = self.buffer.read(cx);
1576                    let mut to_unfold = Vec::new();
1577                    for _ in 0..rng.gen_range(1..=3) {
1578                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1579                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1580                        to_unfold.push(start..end);
1581                    }
1582                    log::info!("unfolding {:?}", to_unfold);
1583                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1584                    snapshot_edits.push((snapshot, edits));
1585                    let (snapshot, edits) = writer.fold(to_unfold, cx.as_ref());
1586                    snapshot_edits.push((snapshot, edits));
1587                }
1588                _ => {
1589                    let buffer = self.buffer.read(cx);
1590                    let mut to_fold = Vec::new();
1591                    for _ in 0..rng.gen_range(1..=2) {
1592                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1593                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1594                        to_fold.push(start..end);
1595                    }
1596                    log::info!("folding {:?}", to_fold);
1597                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1598                    snapshot_edits.push((snapshot, edits));
1599                    let (snapshot, edits) = writer.fold(to_fold, cx.as_ref());
1600                    snapshot_edits.push((snapshot, edits));
1601                }
1602            }
1603            snapshot_edits
1604        }
1605    }
1606}