fold_map.rs

   1use gpui::{AppContext, ModelHandle};
   2use language::{Anchor, AnchorRangeExt, Buffer, Chunk, Point, PointUtf16, TextSummary, ToOffset};
   3use parking_lot::Mutex;
   4use std::{
   5    cmp::{self, Ordering},
   6    iter, mem,
   7    ops::Range,
   8    sync::atomic::{AtomicUsize, Ordering::SeqCst},
   9};
  10use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  11use theme::SyntaxTheme;
  12
  13pub trait ToFoldPoint {
  14    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint;
  15}
  16
  17#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  18pub struct FoldPoint(pub super::Point);
  19
  20impl FoldPoint {
  21    pub fn new(row: u32, column: u32) -> Self {
  22        Self(super::Point::new(row, column))
  23    }
  24
  25    pub fn row(self) -> u32 {
  26        self.0.row
  27    }
  28
  29    pub fn column(self) -> u32 {
  30        self.0.column
  31    }
  32
  33    pub fn row_mut(&mut self) -> &mut u32 {
  34        &mut self.0.row
  35    }
  36
  37    #[cfg(test)]
  38    pub fn column_mut(&mut self) -> &mut u32 {
  39        &mut self.0.column
  40    }
  41
  42    pub fn to_buffer_point(&self, snapshot: &Snapshot) -> Point {
  43        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  44        cursor.seek(self, Bias::Right, &());
  45        let overshoot = self.0 - cursor.start().0 .0;
  46        cursor.start().1 + overshoot
  47    }
  48
  49    pub fn to_buffer_offset(&self, snapshot: &Snapshot) -> usize {
  50        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  51        cursor.seek(self, Bias::Right, &());
  52        let overshoot = self.0 - cursor.start().0 .0;
  53        snapshot
  54            .buffer_snapshot
  55            .to_offset(cursor.start().1 + overshoot)
  56    }
  57
  58    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  59        let mut cursor = snapshot
  60            .transforms
  61            .cursor::<(FoldPoint, TransformSummary)>();
  62        cursor.seek(self, Bias::Right, &());
  63        let overshoot = self.0 - cursor.start().1.output.lines;
  64        let mut offset = cursor.start().1.output.bytes;
  65        if !overshoot.is_zero() {
  66            let transform = cursor.item().expect("display point out of range");
  67            assert!(transform.output_text.is_none());
  68            let end_buffer_offset = snapshot
  69                .buffer_snapshot
  70                .to_offset(cursor.start().1.input.lines + overshoot);
  71            offset += end_buffer_offset - cursor.start().1.input.bytes;
  72        }
  73        FoldOffset(offset)
  74    }
  75}
  76
  77impl ToFoldPoint for Point {
  78    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  79        let mut cursor = snapshot.transforms.cursor::<(Point, FoldPoint)>();
  80        cursor.seek(self, Bias::Right, &());
  81        if cursor.item().map_or(false, |t| t.is_fold()) {
  82            if bias == Bias::Left || *self == cursor.start().0 {
  83                cursor.start().1
  84            } else {
  85                cursor.end(&()).1
  86            }
  87        } else {
  88            let overshoot = *self - cursor.start().0;
  89            FoldPoint(cmp::min(
  90                cursor.start().1 .0 + overshoot,
  91                cursor.end(&()).1 .0,
  92            ))
  93        }
  94    }
  95}
  96
  97pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  98
  99impl<'a> FoldMapWriter<'a> {
 100    pub fn fold<T: ToOffset>(
 101        &mut self,
 102        ranges: impl IntoIterator<Item = Range<T>>,
 103        cx: &AppContext,
 104    ) -> (Snapshot, Vec<FoldEdit>) {
 105        let mut edits = Vec::new();
 106        let mut folds = Vec::new();
 107        let buffer = self.0.buffer.read(cx).snapshot();
 108        for range in ranges.into_iter() {
 109            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 110            if range.start != range.end {
 111                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 112                folds.push(fold);
 113                edits.push(text::Edit {
 114                    old: range.clone(),
 115                    new: range,
 116                });
 117            }
 118        }
 119
 120        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 121
 122        self.0.folds = {
 123            let mut new_tree = SumTree::new();
 124            let mut cursor = self.0.folds.cursor::<Fold>();
 125            for fold in folds {
 126                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 127                new_tree.push(fold, &buffer);
 128            }
 129            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 130            new_tree
 131        };
 132
 133        consolidate_buffer_edits(&mut edits);
 134        let edits = self.0.apply_edits(edits, cx);
 135        let snapshot = Snapshot {
 136            transforms: self.0.transforms.lock().clone(),
 137            folds: self.0.folds.clone(),
 138            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 139            version: self.0.version.load(SeqCst),
 140        };
 141        (snapshot, edits)
 142    }
 143
 144    pub fn unfold<T: ToOffset>(
 145        &mut self,
 146        ranges: impl IntoIterator<Item = Range<T>>,
 147        cx: &AppContext,
 148    ) -> (Snapshot, Vec<FoldEdit>) {
 149        let mut edits = Vec::new();
 150        let mut fold_ixs_to_delete = Vec::new();
 151        let buffer = self.0.buffer.read(cx).snapshot();
 152        for range in ranges.into_iter() {
 153            // Remove intersecting folds and add their ranges to edits that are passed to apply_edits.
 154            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 155            while let Some(fold) = folds_cursor.item() {
 156                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 157                edits.push(text::Edit {
 158                    old: offset_range.clone(),
 159                    new: offset_range,
 160                });
 161                fold_ixs_to_delete.push(*folds_cursor.start());
 162                folds_cursor.next(&buffer);
 163            }
 164        }
 165
 166        fold_ixs_to_delete.sort_unstable();
 167        fold_ixs_to_delete.dedup();
 168
 169        self.0.folds = {
 170            let mut cursor = self.0.folds.cursor::<usize>();
 171            let mut folds = SumTree::new();
 172            for fold_ix in fold_ixs_to_delete {
 173                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 174                cursor.next(&buffer);
 175            }
 176            folds.push_tree(cursor.suffix(&buffer), &buffer);
 177            folds
 178        };
 179
 180        consolidate_buffer_edits(&mut edits);
 181        let edits = self.0.apply_edits(edits, cx);
 182        let snapshot = Snapshot {
 183            transforms: self.0.transforms.lock().clone(),
 184            folds: self.0.folds.clone(),
 185            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 186            version: self.0.version.load(SeqCst),
 187        };
 188        (snapshot, edits)
 189    }
 190}
 191
 192pub struct FoldMap {
 193    buffer: ModelHandle<Buffer>,
 194    transforms: Mutex<SumTree<Transform>>,
 195    folds: SumTree<Fold>,
 196    last_sync: Mutex<SyncState>,
 197    version: AtomicUsize,
 198}
 199
 200#[derive(Clone)]
 201struct SyncState {
 202    version: clock::Global,
 203    parse_count: usize,
 204    diagnostics_update_count: usize,
 205}
 206
 207impl FoldMap {
 208    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
 209        let buffer = buffer_handle.read(cx);
 210        let this = Self {
 211            buffer: buffer_handle,
 212            folds: Default::default(),
 213            transforms: Mutex::new(SumTree::from_item(
 214                Transform {
 215                    summary: TransformSummary {
 216                        input: buffer.text_summary(),
 217                        output: buffer.text_summary(),
 218                    },
 219                    output_text: None,
 220                },
 221                &(),
 222            )),
 223            last_sync: Mutex::new(SyncState {
 224                version: buffer.version(),
 225                parse_count: buffer.parse_count(),
 226                diagnostics_update_count: buffer.diagnostics_update_count(),
 227            }),
 228            version: AtomicUsize::new(0),
 229        };
 230        let (snapshot, _) = this.read(cx);
 231        (this, snapshot)
 232    }
 233
 234    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 235        let edits = self.sync(cx);
 236        self.check_invariants(cx);
 237        let snapshot = Snapshot {
 238            transforms: self.transforms.lock().clone(),
 239            folds: self.folds.clone(),
 240            buffer_snapshot: self.buffer.read(cx).snapshot(),
 241            version: self.version.load(SeqCst),
 242        };
 243        (snapshot, edits)
 244    }
 245
 246    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 247        let (snapshot, edits) = self.read(cx);
 248        (FoldMapWriter(self), snapshot, edits)
 249    }
 250
 251    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 252        let buffer = self.buffer.read(cx);
 253        let last_sync = mem::replace(
 254            &mut *self.last_sync.lock(),
 255            SyncState {
 256                version: buffer.version(),
 257                parse_count: buffer.parse_count(),
 258                diagnostics_update_count: buffer.diagnostics_update_count(),
 259            },
 260        );
 261        let edits = buffer
 262            .edits_since(&last_sync.version)
 263            .map(Into::into)
 264            .collect::<Vec<_>>();
 265        if edits.is_empty() {
 266            if last_sync.parse_count != buffer.parse_count()
 267                || last_sync.diagnostics_update_count != buffer.diagnostics_update_count()
 268            {
 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<text::Edit<usize>>, 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.start, Bias::Left, &()), &());
 299            edit.new.start -= edit.old.start - cursor.start();
 300            edit.old.start = *cursor.start();
 301
 302            cursor.seek(&edit.old.end, Bias::Right, &());
 303            cursor.next(&());
 304
 305            let mut delta = edit.new.len() as isize - edit.old.len() as isize;
 306            loop {
 307                edit.old.end = *cursor.start();
 308
 309                if let Some(next_edit) = buffer_edits_iter.peek() {
 310                    if next_edit.old.start > edit.old.end {
 311                        break;
 312                    }
 313
 314                    let next_edit = buffer_edits_iter.next().unwrap();
 315                    delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
 316
 317                    if next_edit.old.end >= edit.old.end {
 318                        edit.old.end = next_edit.old.end;
 319                        cursor.seek(&edit.old.end, Bias::Right, &());
 320                        cursor.next(&());
 321                    }
 322                } else {
 323                    break;
 324                }
 325            }
 326
 327            edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
 328
 329            let anchor = buffer.anchor_before(edit.new.start);
 330            let mut folds_cursor = self.folds.cursor::<Fold>();
 331            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 332
 333            let mut folds = iter::from_fn({
 334                let buffer = &buffer;
 335                move || {
 336                    let item = folds_cursor
 337                        .item()
 338                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 339                    folds_cursor.next(buffer);
 340                    item
 341                }
 342            })
 343            .peekable();
 344
 345            while folds.peek().map_or(false, |fold| fold.start < edit.new.end) {
 346                let mut fold = folds.next().unwrap();
 347                let sum = new_transforms.summary();
 348
 349                assert!(fold.start >= sum.input.bytes);
 350
 351                while folds
 352                    .peek()
 353                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 354                {
 355                    let next_fold = folds.next().unwrap();
 356                    if next_fold.end > fold.end {
 357                        fold.end = next_fold.end;
 358                    }
 359                }
 360
 361                if fold.start > sum.input.bytes {
 362                    let text_summary = buffer.text_summary_for_range(sum.input.bytes..fold.start);
 363                    new_transforms.push(
 364                        Transform {
 365                            summary: TransformSummary {
 366                                output: text_summary.clone(),
 367                                input: text_summary,
 368                            },
 369                            output_text: None,
 370                        },
 371                        &(),
 372                    );
 373                }
 374
 375                if fold.end > fold.start {
 376                    let output_text = "";
 377                    let chars = output_text.chars().count() as u32;
 378                    let lines = Point::new(0, output_text.len() as u32);
 379                    let lines_utf16 = PointUtf16::new(0, output_text.encode_utf16().count() as u32);
 380                    new_transforms.push(
 381                        Transform {
 382                            summary: TransformSummary {
 383                                output: TextSummary {
 384                                    bytes: output_text.len(),
 385                                    lines,
 386                                    lines_utf16,
 387                                    first_line_chars: chars,
 388                                    last_line_chars: chars,
 389                                    longest_row: 0,
 390                                    longest_row_chars: chars,
 391                                },
 392                                input: buffer.text_summary_for_range(fold.start..fold.end),
 393                            },
 394                            output_text: Some(output_text),
 395                        },
 396                        &(),
 397                    );
 398                }
 399            }
 400
 401            let sum = new_transforms.summary();
 402            if sum.input.bytes < edit.new.end {
 403                let text_summary = buffer.text_summary_for_range(sum.input.bytes..edit.new.end);
 404                new_transforms.push(
 405                    Transform {
 406                        summary: TransformSummary {
 407                            output: text_summary.clone(),
 408                            input: text_summary,
 409                        },
 410                        output_text: None,
 411                    },
 412                    &(),
 413                );
 414            }
 415        }
 416
 417        new_transforms.push_tree(cursor.suffix(&()), &());
 418        if new_transforms.is_empty() {
 419            let text_summary = buffer.text_summary();
 420            new_transforms.push(
 421                Transform {
 422                    summary: TransformSummary {
 423                        output: text_summary.clone(),
 424                        input: text_summary,
 425                    },
 426                    output_text: None,
 427                },
 428                &(),
 429            );
 430        }
 431
 432        drop(cursor);
 433
 434        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 435        {
 436            let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 437            let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 438
 439            for mut edit in buffer_edits {
 440                old_transforms.seek(&edit.old.start, Bias::Left, &());
 441                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 442                    edit.old.start = old_transforms.start().0;
 443                }
 444                let old_start =
 445                    old_transforms.start().1 .0 + (edit.old.start - old_transforms.start().0);
 446
 447                old_transforms.seek_forward(&edit.old.end, Bias::Right, &());
 448                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 449                    old_transforms.next(&());
 450                    edit.old.end = old_transforms.start().0;
 451                }
 452                let old_end =
 453                    old_transforms.start().1 .0 + (edit.old.end - old_transforms.start().0);
 454
 455                new_transforms.seek(&edit.new.start, Bias::Left, &());
 456                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 457                    edit.new.start = new_transforms.start().0;
 458                }
 459                let new_start =
 460                    new_transforms.start().1 .0 + (edit.new.start - new_transforms.start().0);
 461
 462                new_transforms.seek_forward(&edit.new.end, Bias::Right, &());
 463                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 464                    new_transforms.next(&());
 465                    edit.new.end = new_transforms.start().0;
 466                }
 467                let new_end =
 468                    new_transforms.start().1 .0 + (edit.new.end - new_transforms.start().0);
 469
 470                fold_edits.push(FoldEdit {
 471                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 472                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 473                });
 474            }
 475
 476            consolidate_fold_edits(&mut fold_edits);
 477        }
 478
 479        *transforms = new_transforms;
 480        self.version.fetch_add(1, SeqCst);
 481        fold_edits
 482    }
 483}
 484
 485#[derive(Clone)]
 486pub struct Snapshot {
 487    transforms: SumTree<Transform>,
 488    folds: SumTree<Fold>,
 489    buffer_snapshot: language::Snapshot,
 490    pub version: usize,
 491}
 492
 493impl Snapshot {
 494    #[cfg(test)]
 495    pub fn text(&self) -> String {
 496        self.chunks(FoldOffset(0)..self.len(), None)
 497            .map(|c| c.text)
 498            .collect()
 499    }
 500
 501    #[cfg(test)]
 502    pub fn fold_count(&self) -> usize {
 503        self.folds.items(&self.buffer_snapshot).len()
 504    }
 505
 506    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 507        let mut summary = TextSummary::default();
 508
 509        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 510        cursor.seek(&range.start, Bias::Right, &());
 511        if let Some(transform) = cursor.item() {
 512            let start_in_transform = range.start.0 - cursor.start().0 .0;
 513            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 514            if let Some(output_text) = transform.output_text {
 515                summary = TextSummary::from(
 516                    &output_text
 517                        [start_in_transform.column as usize..end_in_transform.column as usize],
 518                );
 519            } else {
 520                let buffer_start = cursor.start().1 + start_in_transform;
 521                let buffer_end = cursor.start().1 + end_in_transform;
 522                summary = self
 523                    .buffer_snapshot
 524                    .text_summary_for_range(buffer_start..buffer_end);
 525            }
 526        }
 527
 528        if range.end > cursor.end(&()).0 {
 529            cursor.next(&());
 530            summary += &cursor
 531                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 532                .output;
 533            if let Some(transform) = cursor.item() {
 534                let end_in_transform = range.end.0 - cursor.start().0 .0;
 535                if let Some(output_text) = transform.output_text {
 536                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 537                } else {
 538                    let buffer_start = cursor.start().1;
 539                    let buffer_end = cursor.start().1 + end_in_transform;
 540                    summary += self
 541                        .buffer_snapshot
 542                        .text_summary_for_range(buffer_start..buffer_end);
 543                }
 544            }
 545        }
 546
 547        summary
 548    }
 549
 550    pub fn len(&self) -> FoldOffset {
 551        FoldOffset(self.transforms.summary().output.bytes)
 552    }
 553
 554    #[cfg(test)]
 555    pub fn line_len(&self, row: u32) -> u32 {
 556        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 557        let line_end = if row >= self.max_point().row() {
 558            self.len().0
 559        } else {
 560            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 561        };
 562        (line_end - line_start) as u32
 563    }
 564
 565    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 566        if start_row > self.transforms.summary().output.lines.row {
 567            panic!("invalid display row {}", start_row);
 568        }
 569
 570        let fold_point = FoldPoint::new(start_row, 0);
 571        let mut cursor = self.transforms.cursor();
 572        cursor.seek(&fold_point, Bias::Left, &());
 573        BufferRows { fold_point, cursor }
 574    }
 575
 576    pub fn max_point(&self) -> FoldPoint {
 577        FoldPoint(self.transforms.summary().output.lines)
 578    }
 579
 580    #[cfg(test)]
 581    pub fn longest_row(&self) -> u32 {
 582        self.transforms.summary().output.longest_row
 583    }
 584
 585    pub fn folds_in_range<'a, T>(
 586        &'a self,
 587        range: Range<T>,
 588    ) -> impl Iterator<Item = &'a Range<Anchor>>
 589    where
 590        T: ToOffset,
 591    {
 592        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 593        iter::from_fn(move || {
 594            let item = folds.item().map(|f| &f.0);
 595            folds.next(&self.buffer_snapshot);
 596            item
 597        })
 598    }
 599
 600    pub fn intersects_fold<T>(&self, offset: T) -> bool
 601    where
 602        T: ToOffset,
 603    {
 604        let offset = offset.to_offset(&self.buffer_snapshot);
 605        let mut cursor = self.transforms.cursor::<usize>();
 606        cursor.seek(&offset, Bias::Right, &());
 607        cursor.item().map_or(false, |t| t.output_text.is_some())
 608    }
 609
 610    pub fn is_line_folded(&self, output_row: u32) -> bool {
 611        let mut cursor = self.transforms.cursor::<FoldPoint>();
 612        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 613        while let Some(transform) = cursor.item() {
 614            if transform.output_text.is_some() {
 615                return true;
 616            }
 617            if cursor.end(&()).row() == output_row {
 618                cursor.next(&())
 619            } else {
 620                break;
 621            }
 622        }
 623        false
 624    }
 625
 626    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 627        let start = start.to_offset(self);
 628        self.chunks(start..self.len(), None)
 629            .flat_map(|chunk| chunk.text.chars())
 630    }
 631
 632    pub fn chunks<'a>(
 633        &'a self,
 634        range: Range<FoldOffset>,
 635        theme: Option<&'a SyntaxTheme>,
 636    ) -> Chunks<'a> {
 637        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 638
 639        transform_cursor.seek(&range.end, Bias::Right, &());
 640        let overshoot = range.end.0 - transform_cursor.start().0 .0;
 641        let buffer_end = transform_cursor.start().1 + overshoot;
 642
 643        transform_cursor.seek(&range.start, Bias::Right, &());
 644        let overshoot = range.start.0 - transform_cursor.start().0 .0;
 645        let buffer_start = transform_cursor.start().1 + overshoot;
 646
 647        Chunks {
 648            transform_cursor,
 649            buffer_chunks: self.buffer_snapshot.chunks(buffer_start..buffer_end, theme),
 650            buffer_chunk: None,
 651            buffer_offset: buffer_start,
 652            output_offset: range.start.0,
 653            max_output_offset: range.end.0,
 654        }
 655    }
 656
 657    #[cfg(test)]
 658    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 659        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 660        cursor.seek(&offset, Bias::Right, &());
 661        if let Some(transform) = cursor.item() {
 662            let transform_start = cursor.start().0 .0;
 663            if transform.output_text.is_some() {
 664                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 665                    FoldOffset(transform_start)
 666                } else {
 667                    FoldOffset(cursor.end(&()).0 .0)
 668                }
 669            } else {
 670                let overshoot = offset.0 - transform_start;
 671                let buffer_offset = cursor.start().1 + overshoot;
 672                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 673                FoldOffset(
 674                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 675                        as usize,
 676                )
 677            }
 678        } else {
 679            FoldOffset(self.transforms.summary().output.bytes)
 680        }
 681    }
 682
 683    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 684        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 685        cursor.seek(&point, Bias::Right, &());
 686        if let Some(transform) = cursor.item() {
 687            let transform_start = cursor.start().0 .0;
 688            if transform.output_text.is_some() {
 689                if point.0 == transform_start || matches!(bias, Bias::Left) {
 690                    FoldPoint(transform_start)
 691                } else {
 692                    FoldPoint(cursor.end(&()).0 .0)
 693                }
 694            } else {
 695                let overshoot = point.0 - transform_start;
 696                let buffer_position = cursor.start().1 + overshoot;
 697                let clipped_buffer_position =
 698                    self.buffer_snapshot.clip_point(buffer_position, bias);
 699                FoldPoint::new(
 700                    point.row(),
 701                    ((point.column() as i32) + clipped_buffer_position.column as i32
 702                        - buffer_position.column as i32) as u32,
 703                )
 704            }
 705        } else {
 706            FoldPoint(self.transforms.summary().output.lines)
 707        }
 708    }
 709}
 710
 711fn intersecting_folds<'a, T>(
 712    buffer: &'a text::Snapshot,
 713    folds: &'a SumTree<Fold>,
 714    range: Range<T>,
 715    inclusive: bool,
 716) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 717where
 718    T: ToOffset,
 719{
 720    let start = buffer.anchor_before(range.start.to_offset(buffer));
 721    let end = buffer.anchor_after(range.end.to_offset(buffer));
 722    folds.filter::<_, usize>(
 723        move |summary| {
 724            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 725            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 726
 727            if inclusive {
 728                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 729            } else {
 730                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 731            }
 732        },
 733        buffer,
 734    )
 735}
 736
 737fn consolidate_buffer_edits(edits: &mut Vec<text::Edit<usize>>) {
 738    edits.sort_unstable_by(|a, b| {
 739        a.old
 740            .start
 741            .cmp(&b.old.start)
 742            .then_with(|| b.old.end.cmp(&a.old.end))
 743    });
 744
 745    let mut i = 1;
 746    while i < edits.len() {
 747        let edit = edits[i].clone();
 748        let prev_edit = &mut edits[i - 1];
 749        if prev_edit.old.end >= edit.old.start {
 750            prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 751            prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 752            prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 753            edits.remove(i);
 754            continue;
 755        }
 756        i += 1;
 757    }
 758}
 759
 760fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 761    edits.sort_unstable_by(|a, b| {
 762        a.old_bytes
 763            .start
 764            .cmp(&b.old_bytes.start)
 765            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 766    });
 767
 768    let mut i = 1;
 769    while i < edits.len() {
 770        let edit = edits[i].clone();
 771        let prev_edit = &mut edits[i - 1];
 772        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 773            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 774            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 775            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 776            edits.remove(i);
 777            continue;
 778        }
 779        i += 1;
 780    }
 781}
 782
 783#[derive(Clone, Debug, Default, Eq, PartialEq)]
 784struct Transform {
 785    summary: TransformSummary,
 786    output_text: Option<&'static str>,
 787}
 788
 789impl Transform {
 790    fn is_fold(&self) -> bool {
 791        self.output_text.is_some()
 792    }
 793}
 794
 795#[derive(Clone, Debug, Default, Eq, PartialEq)]
 796struct TransformSummary {
 797    output: TextSummary,
 798    input: TextSummary,
 799}
 800
 801impl sum_tree::Item for Transform {
 802    type Summary = TransformSummary;
 803
 804    fn summary(&self) -> Self::Summary {
 805        self.summary.clone()
 806    }
 807}
 808
 809impl sum_tree::Summary for TransformSummary {
 810    type Context = ();
 811
 812    fn add_summary(&mut self, other: &Self, _: &()) {
 813        self.input += &other.input;
 814        self.output += &other.output;
 815    }
 816}
 817
 818#[derive(Clone, Debug)]
 819struct Fold(Range<Anchor>);
 820
 821impl Default for Fold {
 822    fn default() -> Self {
 823        Self(Anchor::min()..Anchor::max())
 824    }
 825}
 826
 827impl sum_tree::Item for Fold {
 828    type Summary = FoldSummary;
 829
 830    fn summary(&self) -> Self::Summary {
 831        FoldSummary {
 832            start: self.0.start.clone(),
 833            end: self.0.end.clone(),
 834            min_start: self.0.start.clone(),
 835            max_end: self.0.end.clone(),
 836            count: 1,
 837        }
 838    }
 839}
 840
 841#[derive(Clone, Debug)]
 842struct FoldSummary {
 843    start: Anchor,
 844    end: Anchor,
 845    min_start: Anchor,
 846    max_end: Anchor,
 847    count: usize,
 848}
 849
 850impl Default for FoldSummary {
 851    fn default() -> Self {
 852        Self {
 853            start: Anchor::min(),
 854            end: Anchor::max(),
 855            min_start: Anchor::max(),
 856            max_end: Anchor::min(),
 857            count: 0,
 858        }
 859    }
 860}
 861
 862impl sum_tree::Summary for FoldSummary {
 863    type Context = text::Snapshot;
 864
 865    fn add_summary(&mut self, other: &Self, buffer: &text::Snapshot) {
 866        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 867            self.min_start = other.min_start.clone();
 868        }
 869        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 870            self.max_end = other.max_end.clone();
 871        }
 872
 873        #[cfg(debug_assertions)]
 874        {
 875            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 876            assert!(start_comparison <= Ordering::Equal);
 877            if start_comparison == Ordering::Equal {
 878                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 879            }
 880        }
 881
 882        self.start = other.start.clone();
 883        self.end = other.end.clone();
 884        self.count += other.count;
 885    }
 886}
 887
 888impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 889    fn add_summary(&mut self, summary: &'a FoldSummary, _: &text::Snapshot) {
 890        self.0.start = summary.start.clone();
 891        self.0.end = summary.end.clone();
 892    }
 893}
 894
 895impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 896    fn cmp(&self, other: &Self, buffer: &text::Snapshot) -> Ordering {
 897        self.0.cmp(&other.0, buffer).unwrap()
 898    }
 899}
 900
 901impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 902    fn add_summary(&mut self, summary: &'a FoldSummary, _: &text::Snapshot) {
 903        *self += summary.count;
 904    }
 905}
 906
 907pub struct BufferRows<'a> {
 908    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 909    fold_point: FoldPoint,
 910}
 911
 912impl<'a> Iterator for BufferRows<'a> {
 913    type Item = u32;
 914
 915    fn next(&mut self) -> Option<Self::Item> {
 916        while self.fold_point > self.cursor.end(&()).0 {
 917            self.cursor.next(&());
 918            if self.cursor.item().is_none() {
 919                // TODO: Return a bool from next?
 920                break;
 921            }
 922        }
 923
 924        if self.cursor.item().is_some() {
 925            let overshoot = self.fold_point.0 - self.cursor.start().0 .0;
 926            let buffer_point = self.cursor.start().1 + overshoot;
 927            *self.fold_point.row_mut() += 1;
 928            Some(buffer_point.row)
 929        } else {
 930            None
 931        }
 932    }
 933}
 934
 935pub struct Chunks<'a> {
 936    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 937    buffer_chunks: language::Chunks<'a>,
 938    buffer_chunk: Option<(usize, Chunk<'a>)>,
 939    buffer_offset: usize,
 940    output_offset: usize,
 941    max_output_offset: usize,
 942}
 943
 944impl<'a> Iterator for Chunks<'a> {
 945    type Item = Chunk<'a>;
 946
 947    fn next(&mut self) -> Option<Self::Item> {
 948        if self.output_offset >= self.max_output_offset {
 949            return None;
 950        }
 951
 952        let transform = if let Some(item) = self.transform_cursor.item() {
 953            item
 954        } else {
 955            return None;
 956        };
 957
 958        // If we're in a fold, then return the fold's display text and
 959        // advance the transform and buffer cursors to the end of the fold.
 960        if let Some(output_text) = transform.output_text {
 961            self.buffer_chunk.take();
 962            self.buffer_offset += transform.summary.input.bytes;
 963            self.buffer_chunks.seek(self.buffer_offset);
 964
 965            while self.buffer_offset >= self.transform_cursor.end(&()).1
 966                && self.transform_cursor.item().is_some()
 967            {
 968                self.transform_cursor.next(&());
 969            }
 970
 971            self.output_offset += output_text.len();
 972            return Some(Chunk {
 973                text: output_text,
 974                highlight_style: None,
 975                diagnostic: None,
 976            });
 977        }
 978
 979        // Retrieve a chunk from the current location in the buffer.
 980        if self.buffer_chunk.is_none() {
 981            let chunk_offset = self.buffer_chunks.offset();
 982            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
 983        }
 984
 985        // Otherwise, take a chunk from the buffer's text.
 986        if let Some((chunk_offset, mut chunk)) = self.buffer_chunk {
 987            let offset_in_chunk = self.buffer_offset - chunk_offset;
 988            chunk.text = &chunk.text[offset_in_chunk..];
 989
 990            // Truncate the chunk so that it ends at the next fold.
 991            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
 992            if chunk.text.len() >= region_end {
 993                chunk.text = &chunk.text[0..region_end];
 994                self.transform_cursor.next(&());
 995            } else {
 996                self.buffer_chunk.take();
 997            }
 998
 999            self.buffer_offset += chunk.text.len();
1000            self.output_offset += chunk.text.len();
1001            return Some(chunk);
1002        }
1003
1004        None
1005    }
1006}
1007
1008impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1009    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1010        self.0 += &summary.output.lines;
1011    }
1012}
1013
1014#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1015pub struct FoldOffset(pub usize);
1016
1017impl FoldOffset {
1018    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1019        let mut cursor = snapshot
1020            .transforms
1021            .cursor::<(FoldOffset, TransformSummary)>();
1022        cursor.seek(self, Bias::Right, &());
1023        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1024            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1025        } else {
1026            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1027            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1028            buffer_point - cursor.start().1.input.lines
1029        };
1030        FoldPoint(cursor.start().1.output.lines + overshoot)
1031    }
1032}
1033
1034impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1035    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1036        self.0 += &summary.output.bytes;
1037    }
1038}
1039
1040impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1041    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1042        *self += &summary.input.lines;
1043    }
1044}
1045
1046impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1047    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1048        *self += &summary.input.bytes;
1049    }
1050}
1051
1052#[derive(Clone, Debug, PartialEq, Eq)]
1053pub struct FoldEdit {
1054    pub old_bytes: Range<FoldOffset>,
1055    pub new_bytes: Range<FoldOffset>,
1056}
1057
1058#[cfg(test)]
1059impl FoldEdit {
1060    pub fn delta(&self) -> isize {
1061        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1062    }
1063
1064    pub fn deleted_bytes(&self) -> usize {
1065        self.old_bytes.end.0 - self.old_bytes.start.0
1066    }
1067
1068    pub fn inserted_bytes(&self) -> usize {
1069        self.new_bytes.end.0 - self.new_bytes.start.0
1070    }
1071}
1072
1073#[cfg(test)]
1074mod tests {
1075    use super::*;
1076    use crate::{test::sample_text, ToPoint};
1077    use rand::prelude::*;
1078    use std::{env, mem};
1079    use text::RandomCharIter;
1080    use Bias::{Left, Right};
1081
1082    #[gpui::test]
1083    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1084        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1085        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1086
1087        let (mut writer, _, _) = map.write(cx.as_ref());
1088        let (snapshot2, edits) = writer.fold(
1089            vec![
1090                Point::new(0, 2)..Point::new(2, 2),
1091                Point::new(2, 4)..Point::new(4, 1),
1092            ],
1093            cx.as_ref(),
1094        );
1095        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1096        assert_eq!(
1097            edits,
1098            &[
1099                FoldEdit {
1100                    old_bytes: FoldOffset(2)..FoldOffset(16),
1101                    new_bytes: FoldOffset(2)..FoldOffset(5),
1102                },
1103                FoldEdit {
1104                    old_bytes: FoldOffset(18)..FoldOffset(29),
1105                    new_bytes: FoldOffset(7)..FoldOffset(10)
1106                },
1107            ]
1108        );
1109
1110        buffer.update(cx, |buffer, cx| {
1111            buffer.edit(
1112                vec![
1113                    Point::new(0, 0)..Point::new(0, 1),
1114                    Point::new(2, 3)..Point::new(2, 3),
1115                ],
1116                "123",
1117                cx,
1118            );
1119        });
1120        let (snapshot3, edits) = map.read(cx.as_ref());
1121        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1122        assert_eq!(
1123            edits,
1124            &[
1125                FoldEdit {
1126                    old_bytes: FoldOffset(0)..FoldOffset(1),
1127                    new_bytes: FoldOffset(0)..FoldOffset(3),
1128                },
1129                FoldEdit {
1130                    old_bytes: FoldOffset(6)..FoldOffset(6),
1131                    new_bytes: FoldOffset(8)..FoldOffset(11),
1132                },
1133            ]
1134        );
1135
1136        buffer.update(cx, |buffer, cx| {
1137            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx)
1138        });
1139        let (snapshot4, _) = map.read(cx.as_ref());
1140        assert_eq!(snapshot4.text(), "123a…c123456eee");
1141
1142        let (mut writer, _, _) = map.write(cx.as_ref());
1143        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), cx.as_ref());
1144        let (snapshot5, _) = map.read(cx.as_ref());
1145        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1146    }
1147
1148    #[gpui::test]
1149    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1150        let buffer = cx.add_model(|cx| Buffer::new(0, "abcdefghijkl", cx));
1151
1152        {
1153            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1154
1155            let (mut writer, _, _) = map.write(cx.as_ref());
1156            writer.fold(vec![5..8], cx.as_ref());
1157            let (snapshot, _) = map.read(cx.as_ref());
1158            assert_eq!(snapshot.text(), "abcde…ijkl");
1159
1160            // Create an fold adjacent to the start of the first fold.
1161            let (mut writer, _, _) = map.write(cx.as_ref());
1162            writer.fold(vec![0..1, 2..5], cx.as_ref());
1163            let (snapshot, _) = map.read(cx.as_ref());
1164            assert_eq!(snapshot.text(), "…b…ijkl");
1165
1166            // Create an fold adjacent to the end of the first fold.
1167            let (mut writer, _, _) = map.write(cx.as_ref());
1168            writer.fold(vec![11..11, 8..10], cx.as_ref());
1169            let (snapshot, _) = map.read(cx.as_ref());
1170            assert_eq!(snapshot.text(), "…b…kl");
1171        }
1172
1173        {
1174            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1175
1176            // Create two adjacent folds.
1177            let (mut writer, _, _) = map.write(cx.as_ref());
1178            writer.fold(vec![0..2, 2..5], cx.as_ref());
1179            let (snapshot, _) = map.read(cx.as_ref());
1180            assert_eq!(snapshot.text(), "…fghijkl");
1181
1182            // Edit within one of the folds.
1183            buffer.update(cx, |buffer, cx| buffer.edit(vec![0..1], "12345", cx));
1184            let (snapshot, _) = map.read(cx.as_ref());
1185            assert_eq!(snapshot.text(), "12345…fghijkl");
1186        }
1187    }
1188
1189    #[gpui::test]
1190    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1191        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1192        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1193        let (mut writer, _, _) = map.write(cx.as_ref());
1194        writer.fold(
1195            vec![
1196                Point::new(0, 2)..Point::new(2, 2),
1197                Point::new(0, 4)..Point::new(1, 0),
1198                Point::new(1, 2)..Point::new(3, 2),
1199                Point::new(3, 1)..Point::new(4, 1),
1200            ],
1201            cx.as_ref(),
1202        );
1203        let (snapshot, _) = map.read(cx.as_ref());
1204        assert_eq!(snapshot.text(), "aa…eeeee");
1205    }
1206
1207    #[gpui::test]
1208    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1209        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1210        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1211
1212        let (mut writer, _, _) = map.write(cx.as_ref());
1213        writer.fold(
1214            vec![
1215                Point::new(0, 2)..Point::new(2, 2),
1216                Point::new(3, 1)..Point::new(4, 1),
1217            ],
1218            cx.as_ref(),
1219        );
1220        let (snapshot, _) = map.read(cx.as_ref());
1221        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1222
1223        buffer.update(cx, |buffer, cx| {
1224            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx)
1225        });
1226        let (snapshot, _) = map.read(cx.as_ref());
1227        assert_eq!(snapshot.text(), "aa…eeeee");
1228    }
1229
1230    #[gpui::test]
1231    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1232        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1233        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1234        let buffer = buffer.read(cx);
1235
1236        let (mut writer, _, _) = map.write(cx.as_ref());
1237        writer.fold(
1238            vec![
1239                Point::new(0, 2)..Point::new(2, 2),
1240                Point::new(0, 4)..Point::new(1, 0),
1241                Point::new(1, 2)..Point::new(3, 2),
1242                Point::new(3, 1)..Point::new(4, 1),
1243            ],
1244            cx.as_ref(),
1245        );
1246        let (snapshot, _) = map.read(cx.as_ref());
1247        let fold_ranges = snapshot
1248            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1249            .map(|fold| fold.start.to_point(buffer)..fold.end.to_point(buffer))
1250            .collect::<Vec<_>>();
1251        assert_eq!(
1252            fold_ranges,
1253            vec![
1254                Point::new(0, 2)..Point::new(2, 2),
1255                Point::new(1, 2)..Point::new(3, 2)
1256            ]
1257        );
1258    }
1259
1260    #[gpui::test(iterations = 100)]
1261    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1262        let operations = env::var("OPERATIONS")
1263            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1264            .unwrap_or(10);
1265
1266        let buffer = cx.add_model(|cx| {
1267            let len = rng.gen_range(0..10);
1268            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1269            Buffer::new(0, text, cx)
1270        });
1271        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1272
1273        let (mut initial_snapshot, _) = map.read(cx.as_ref());
1274        let mut snapshot_edits = Vec::new();
1275
1276        for _ in 0..operations {
1277            log::info!("text: {:?}", buffer.read(cx).text());
1278            match rng.gen_range(0..=100) {
1279                0..=59 => {
1280                    snapshot_edits.extend(map.randomly_mutate(&mut rng, cx.as_ref()));
1281                }
1282                _ => {
1283                    let edits = buffer.update(cx, |buffer, _| {
1284                        let start_version = buffer.version.clone();
1285                        let edit_count = rng.gen_range(1..=5);
1286                        buffer.randomly_edit(&mut rng, edit_count);
1287                        buffer
1288                            .edits_since::<Point>(&start_version)
1289                            .collect::<Vec<_>>()
1290                    });
1291                    log::info!("editing {:?}", edits);
1292                }
1293            }
1294
1295            let buffer = map.buffer.read(cx).snapshot();
1296            let mut expected_text: String = buffer.text().to_string();
1297            let mut expected_buffer_rows = Vec::new();
1298            let mut next_row = buffer.max_point().row;
1299            for fold_range in map.merged_fold_ranges(cx.as_ref()).into_iter().rev() {
1300                let fold_start = buffer.point_for_offset(fold_range.start).unwrap();
1301                let fold_end = buffer.point_for_offset(fold_range.end).unwrap();
1302                expected_buffer_rows.extend((fold_end.row + 1..=next_row).rev());
1303                next_row = fold_start.row;
1304
1305                expected_text.replace_range(fold_range.start..fold_range.end, "");
1306            }
1307            expected_buffer_rows.extend((0..=next_row).rev());
1308            expected_buffer_rows.reverse();
1309
1310            let (snapshot, edits) = map.read(cx.as_ref());
1311            assert_eq!(snapshot.text(), expected_text);
1312            snapshot_edits.push((snapshot.clone(), edits));
1313
1314            for (output_row, line) in expected_text.lines().enumerate() {
1315                let line_len = snapshot.line_len(output_row as u32);
1316                assert_eq!(line_len, line.len() as u32);
1317            }
1318
1319            let longest_row = snapshot.longest_row();
1320            let longest_char_column = expected_text
1321                .split('\n')
1322                .nth(longest_row as usize)
1323                .unwrap()
1324                .chars()
1325                .count();
1326            let mut fold_point = FoldPoint::new(0, 0);
1327            let mut fold_offset = FoldOffset(0);
1328            let mut char_column = 0;
1329            for c in expected_text.chars() {
1330                let buffer_point = fold_point.to_buffer_point(&snapshot);
1331                let buffer_offset = buffer_point.to_offset(&buffer);
1332                assert_eq!(
1333                    buffer_point.to_fold_point(&snapshot, Right),
1334                    fold_point,
1335                    "{:?} -> fold point",
1336                    buffer_point,
1337                );
1338                assert_eq!(
1339                    fold_point.to_buffer_offset(&snapshot),
1340                    buffer_offset,
1341                    "fold_point.to_buffer_offset({:?})",
1342                    fold_point,
1343                );
1344                assert_eq!(
1345                    fold_point.to_offset(&snapshot),
1346                    fold_offset,
1347                    "fold_point.to_offset({:?})",
1348                    fold_point,
1349                );
1350
1351                if c == '\n' {
1352                    *fold_point.row_mut() += 1;
1353                    *fold_point.column_mut() = 0;
1354                    char_column = 0;
1355                } else {
1356                    *fold_point.column_mut() += c.len_utf8() as u32;
1357                    char_column += 1;
1358                }
1359                fold_offset.0 += c.len_utf8();
1360                if char_column > longest_char_column {
1361                    panic!(
1362                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1363                        longest_row,
1364                        longest_char_column,
1365                        fold_point.row(),
1366                        char_column
1367                    );
1368                }
1369            }
1370
1371            for _ in 0..5 {
1372                let mut start = snapshot
1373                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Left);
1374                let mut end = snapshot
1375                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1376                if start > end {
1377                    mem::swap(&mut start, &mut end);
1378                }
1379
1380                let text = &expected_text[start.0..end.0];
1381                log::info!("slicing {:?}..{:?} (text: {:?})", start, end, text);
1382                assert_eq!(
1383                    snapshot
1384                        .chunks(start..end, None)
1385                        .map(|c| c.text)
1386                        .collect::<String>(),
1387                    text,
1388                );
1389            }
1390
1391            for (idx, buffer_row) in expected_buffer_rows.iter().enumerate() {
1392                let fold_row = Point::new(*buffer_row, 0)
1393                    .to_fold_point(&snapshot, Right)
1394                    .row();
1395                assert_eq!(
1396                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1397                    expected_buffer_rows[idx..],
1398                );
1399            }
1400
1401            for fold_range in map.merged_fold_ranges(cx.as_ref()) {
1402                let fold_point = fold_range
1403                    .start
1404                    .to_point(&buffer)
1405                    .to_fold_point(&snapshot, Right);
1406                assert!(snapshot.is_line_folded(fold_point.row()));
1407            }
1408
1409            for _ in 0..5 {
1410                let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1411                let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1412                let expected_folds = map
1413                    .folds
1414                    .items(&buffer)
1415                    .into_iter()
1416                    .filter(|fold| {
1417                        let start = buffer.anchor_before(start);
1418                        let end = buffer.anchor_after(end);
1419                        start.cmp(&fold.0.end, &buffer).unwrap() == Ordering::Less
1420                            && end.cmp(&fold.0.start, &buffer).unwrap() == Ordering::Greater
1421                    })
1422                    .map(|fold| fold.0)
1423                    .collect::<Vec<_>>();
1424
1425                assert_eq!(
1426                    snapshot
1427                        .folds_in_range(start..end)
1428                        .cloned()
1429                        .collect::<Vec<_>>(),
1430                    expected_folds
1431                );
1432            }
1433
1434            let text = snapshot.text();
1435            for _ in 0..5 {
1436                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1437                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1438                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1439                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1440                let mut start =
1441                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1442                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1443                if start > end {
1444                    mem::swap(&mut start, &mut end);
1445                }
1446
1447                let lines = start..end;
1448                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1449                assert_eq!(
1450                    snapshot.text_summary_for_range(lines),
1451                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1452                )
1453            }
1454
1455            let mut text = initial_snapshot.text();
1456            for (snapshot, edits) in snapshot_edits.drain(..) {
1457                let new_text = snapshot.text();
1458                let mut delta = 0isize;
1459                for edit in edits {
1460                    let old_bytes = ((edit.old_bytes.start.0 as isize) + delta) as usize
1461                        ..((edit.old_bytes.end.0 as isize) + delta) as usize;
1462                    let new_bytes = edit.new_bytes.start.0..edit.new_bytes.end.0;
1463                    delta += edit.delta();
1464                    text.replace_range(old_bytes, &new_text[new_bytes]);
1465                }
1466
1467                assert_eq!(text, new_text);
1468                initial_snapshot = snapshot;
1469            }
1470        }
1471    }
1472
1473    #[gpui::test]
1474    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1475        let text = sample_text(6, 6) + "\n";
1476        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1477
1478        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1479
1480        let (mut writer, _, _) = map.write(cx.as_ref());
1481        writer.fold(
1482            vec![
1483                Point::new(0, 2)..Point::new(2, 2),
1484                Point::new(3, 1)..Point::new(4, 1),
1485            ],
1486            cx.as_ref(),
1487        );
1488
1489        let (snapshot, _) = map.read(cx.as_ref());
1490        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1491        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), [0, 3, 5, 6]);
1492        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [6]);
1493    }
1494
1495    impl FoldMap {
1496        fn merged_fold_ranges(&self, cx: &AppContext) -> Vec<Range<usize>> {
1497            let buffer = self.buffer.read(cx).snapshot();
1498            let mut folds = self.folds.items(&buffer);
1499            // Ensure sorting doesn't change how folds get merged and displayed.
1500            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1501            let mut fold_ranges = folds
1502                .iter()
1503                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1504                .peekable();
1505
1506            let mut merged_ranges = Vec::new();
1507            while let Some(mut fold_range) = fold_ranges.next() {
1508                while let Some(next_range) = fold_ranges.peek() {
1509                    if fold_range.end >= next_range.start {
1510                        if next_range.end > fold_range.end {
1511                            fold_range.end = next_range.end;
1512                        }
1513                        fold_ranges.next();
1514                    } else {
1515                        break;
1516                    }
1517                }
1518                if fold_range.end > fold_range.start {
1519                    merged_ranges.push(fold_range);
1520                }
1521            }
1522            merged_ranges
1523        }
1524
1525        pub fn randomly_mutate(
1526            &mut self,
1527            rng: &mut impl Rng,
1528            cx: &AppContext,
1529        ) -> Vec<(Snapshot, Vec<FoldEdit>)> {
1530            let mut snapshot_edits = Vec::new();
1531            match rng.gen_range(0..=100) {
1532                0..=39 if !self.folds.is_empty() => {
1533                    let buffer = self.buffer.read(cx);
1534                    let mut to_unfold = Vec::new();
1535                    for _ in 0..rng.gen_range(1..=3) {
1536                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1537                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1538                        to_unfold.push(start..end);
1539                    }
1540                    log::info!("unfolding {:?}", to_unfold);
1541                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1542                    snapshot_edits.push((snapshot, edits));
1543                    let (snapshot, edits) = writer.fold(to_unfold, cx.as_ref());
1544                    snapshot_edits.push((snapshot, edits));
1545                }
1546                _ => {
1547                    let buffer = self.buffer.read(cx);
1548                    let mut to_fold = Vec::new();
1549                    for _ in 0..rng.gen_range(1..=2) {
1550                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1551                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1552                        to_fold.push(start..end);
1553                    }
1554                    log::info!("folding {:?}", to_fold);
1555                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1556                    snapshot_edits.push((snapshot, edits));
1557                    let (snapshot, edits) = writer.fold(to_fold, cx.as_ref());
1558                    snapshot_edits.push((snapshot, edits));
1559                }
1560            }
1561            snapshot_edits
1562        }
1563    }
1564}