fold_map.rs

   1use gpui::{AppContext, ModelHandle};
   2use language::{
   3    Anchor, AnchorRangeExt, Buffer, HighlightId, HighlightedChunk, Point, TextSummary, ToOffset,
   4};
   5use parking_lot::Mutex;
   6use std::{
   7    cmp::{self, Ordering},
   8    iter, mem,
   9    ops::Range,
  10    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  11};
  12use sum_tree::{Bias, Cursor, FilterCursor, SumTree};
  13
  14pub trait ToFoldPoint {
  15    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint;
  16}
  17
  18#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  19pub struct FoldPoint(pub super::Point);
  20
  21impl FoldPoint {
  22    pub fn new(row: u32, column: u32) -> Self {
  23        Self(super::Point::new(row, column))
  24    }
  25
  26    pub fn row(self) -> u32 {
  27        self.0.row
  28    }
  29
  30    pub fn column(self) -> u32 {
  31        self.0.column
  32    }
  33
  34    pub fn row_mut(&mut self) -> &mut u32 {
  35        &mut self.0.row
  36    }
  37
  38    #[cfg(test)]
  39    pub fn column_mut(&mut self) -> &mut u32 {
  40        &mut self.0.column
  41    }
  42
  43    pub fn to_buffer_point(&self, snapshot: &Snapshot) -> Point {
  44        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  45        cursor.seek(self, Bias::Right, &());
  46        let overshoot = self.0 - cursor.start().0 .0;
  47        cursor.start().1 + overshoot
  48    }
  49
  50    pub fn to_buffer_offset(&self, snapshot: &Snapshot) -> usize {
  51        let mut cursor = snapshot.transforms.cursor::<(FoldPoint, Point)>();
  52        cursor.seek(self, Bias::Right, &());
  53        let overshoot = self.0 - cursor.start().0 .0;
  54        snapshot
  55            .buffer_snapshot
  56            .to_offset(cursor.start().1 + overshoot)
  57    }
  58
  59    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  60        let mut cursor = snapshot
  61            .transforms
  62            .cursor::<(FoldPoint, TransformSummary)>();
  63        cursor.seek(self, Bias::Right, &());
  64        let overshoot = self.0 - cursor.start().1.output.lines;
  65        let mut offset = cursor.start().1.output.bytes;
  66        if !overshoot.is_zero() {
  67            let transform = cursor.item().expect("display point out of range");
  68            assert!(transform.output_text.is_none());
  69            let end_buffer_offset = snapshot
  70                .buffer_snapshot
  71                .to_offset(cursor.start().1.input.lines + overshoot);
  72            offset += end_buffer_offset - cursor.start().1.input.bytes;
  73        }
  74        FoldOffset(offset)
  75    }
  76}
  77
  78impl ToFoldPoint for Point {
  79    fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  80        let mut cursor = snapshot.transforms.cursor::<(Point, FoldPoint)>();
  81        cursor.seek(self, Bias::Right, &());
  82        if cursor.item().map_or(false, |t| t.is_fold()) {
  83            if bias == Bias::Left || *self == cursor.start().0 {
  84                cursor.start().1
  85            } else {
  86                cursor.end(&()).1
  87            }
  88        } else {
  89            let overshoot = *self - cursor.start().0;
  90            FoldPoint(cmp::min(
  91                cursor.start().1 .0 + overshoot,
  92                cursor.end(&()).1 .0,
  93            ))
  94        }
  95    }
  96}
  97
  98pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  99
 100impl<'a> FoldMapWriter<'a> {
 101    pub fn fold<T: ToOffset>(
 102        &mut self,
 103        ranges: impl IntoIterator<Item = Range<T>>,
 104        cx: &AppContext,
 105    ) -> (Snapshot, Vec<FoldEdit>) {
 106        let mut edits = Vec::new();
 107        let mut folds = Vec::new();
 108        let buffer = self.0.buffer.read(cx).snapshot();
 109        for range in ranges.into_iter() {
 110            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 111            if range.start != range.end {
 112                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 113                folds.push(fold);
 114                edits.push(buffer::Edit {
 115                    old_bytes: range.clone(),
 116                    new_bytes: range.clone(),
 117                    ..Default::default()
 118                });
 119            }
 120        }
 121
 122        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(a, b, &buffer));
 123
 124        self.0.folds = {
 125            let mut new_tree = SumTree::new();
 126            let mut cursor = self.0.folds.cursor::<Fold>();
 127            for fold in folds {
 128                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 129                new_tree.push(fold, &buffer);
 130            }
 131            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 132            new_tree
 133        };
 134
 135        consolidate_buffer_edits(&mut edits);
 136        let edits = self.0.apply_edits(edits, cx);
 137        let snapshot = Snapshot {
 138            transforms: self.0.transforms.lock().clone(),
 139            folds: self.0.folds.clone(),
 140            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 141            version: self.0.version.load(SeqCst),
 142        };
 143        (snapshot, edits)
 144    }
 145
 146    pub fn unfold<T: ToOffset>(
 147        &mut self,
 148        ranges: impl IntoIterator<Item = Range<T>>,
 149        cx: &AppContext,
 150    ) -> (Snapshot, Vec<FoldEdit>) {
 151        let mut edits = Vec::new();
 152        let mut fold_ixs_to_delete = Vec::new();
 153        let buffer = self.0.buffer.read(cx).snapshot();
 154        for range in ranges.into_iter() {
 155            // Remove intersecting folds and add their ranges to edits that are passed to apply_edits.
 156            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 157            while let Some(fold) = folds_cursor.item() {
 158                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 159                edits.push(buffer::Edit {
 160                    old_bytes: offset_range.clone(),
 161                    new_bytes: offset_range,
 162                    ..Default::default()
 163                });
 164                fold_ixs_to_delete.push(*folds_cursor.start());
 165                folds_cursor.next(&buffer);
 166            }
 167        }
 168
 169        fold_ixs_to_delete.sort_unstable();
 170        fold_ixs_to_delete.dedup();
 171
 172        self.0.folds = {
 173            let mut cursor = self.0.folds.cursor::<usize>();
 174            let mut folds = SumTree::new();
 175            for fold_ix in fold_ixs_to_delete {
 176                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 177                cursor.next(&buffer);
 178            }
 179            folds.push_tree(cursor.suffix(&buffer), &buffer);
 180            folds
 181        };
 182
 183        consolidate_buffer_edits(&mut edits);
 184        let edits = self.0.apply_edits(edits, cx);
 185        let snapshot = Snapshot {
 186            transforms: self.0.transforms.lock().clone(),
 187            folds: self.0.folds.clone(),
 188            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 189            version: self.0.version.load(SeqCst),
 190        };
 191        (snapshot, edits)
 192    }
 193}
 194
 195pub struct FoldMap {
 196    buffer: ModelHandle<Buffer>,
 197    transforms: Mutex<SumTree<Transform>>,
 198    folds: SumTree<Fold>,
 199    last_sync: Mutex<SyncState>,
 200    version: AtomicUsize,
 201}
 202
 203#[derive(Clone)]
 204struct SyncState {
 205    version: clock::Global,
 206    parse_count: usize,
 207}
 208
 209impl FoldMap {
 210    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
 211        let buffer = buffer_handle.read(cx);
 212        let this = Self {
 213            buffer: buffer_handle,
 214            folds: Default::default(),
 215            transforms: Mutex::new(SumTree::from_item(
 216                Transform {
 217                    summary: TransformSummary {
 218                        input: buffer.text_summary(),
 219                        output: buffer.text_summary(),
 220                    },
 221                    output_text: None,
 222                },
 223                &(),
 224            )),
 225            last_sync: Mutex::new(SyncState {
 226                version: buffer.version(),
 227                parse_count: buffer.parse_count(),
 228            }),
 229            version: AtomicUsize::new(0),
 230        };
 231        let (snapshot, _) = this.read(cx);
 232        (this, snapshot)
 233    }
 234
 235    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 236        let edits = self.sync(cx);
 237        self.check_invariants(cx);
 238        let snapshot = Snapshot {
 239            transforms: self.transforms.lock().clone(),
 240            folds: self.folds.clone(),
 241            buffer_snapshot: self.buffer.read(cx).snapshot(),
 242            version: self.version.load(SeqCst),
 243        };
 244        (snapshot, edits)
 245    }
 246
 247    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 248        let (snapshot, edits) = self.read(cx);
 249        (FoldMapWriter(self), snapshot, edits)
 250    }
 251
 252    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 253        let buffer = self.buffer.read(cx);
 254        let last_sync = mem::replace(
 255            &mut *self.last_sync.lock(),
 256            SyncState {
 257                version: buffer.version(),
 258                parse_count: buffer.parse_count(),
 259            },
 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                self.version.fetch_add(1, SeqCst);
 268            }
 269            Vec::new()
 270        } else {
 271            self.apply_edits(edits, cx)
 272        }
 273    }
 274
 275    fn check_invariants(&self, cx: &AppContext) {
 276        if cfg!(test) {
 277            let buffer = self.buffer.read(cx);
 278            assert_eq!(
 279                self.transforms.lock().summary().input.bytes,
 280                buffer.len(),
 281                "transform tree does not match buffer's length"
 282            );
 283        }
 284    }
 285
 286    fn apply_edits(&self, buffer_edits: Vec<buffer::Edit>, cx: &AppContext) -> Vec<FoldEdit> {
 287        let buffer = self.buffer.read(cx).snapshot();
 288        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 289
 290        let mut new_transforms = SumTree::new();
 291        let mut transforms = self.transforms.lock();
 292        let mut cursor = transforms.cursor::<usize>();
 293        cursor.seek(&0, Bias::Right, &());
 294
 295        while let Some(mut edit) = buffer_edits_iter.next() {
 296            new_transforms.push_tree(cursor.slice(&edit.old_bytes.start, Bias::Left, &()), &());
 297            edit.new_bytes.start -= edit.old_bytes.start - cursor.start();
 298            edit.old_bytes.start = *cursor.start();
 299
 300            cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 301            cursor.next(&());
 302
 303            let mut delta = edit.delta();
 304            loop {
 305                edit.old_bytes.end = *cursor.start();
 306
 307                if let Some(next_edit) = buffer_edits_iter.peek() {
 308                    if next_edit.old_bytes.start > edit.old_bytes.end {
 309                        break;
 310                    }
 311
 312                    let next_edit = buffer_edits_iter.next().unwrap();
 313                    delta += next_edit.delta();
 314
 315                    if next_edit.old_bytes.end >= edit.old_bytes.end {
 316                        edit.old_bytes.end = next_edit.old_bytes.end;
 317                        cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 318                        cursor.next(&());
 319                    }
 320                } else {
 321                    break;
 322                }
 323            }
 324
 325            edit.new_bytes.end =
 326                ((edit.new_bytes.start + edit.deleted_bytes()) as isize + delta) as usize;
 327
 328            let anchor = buffer.anchor_before(edit.new_bytes.start);
 329            let mut folds_cursor = self.folds.cursor::<Fold>();
 330            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 331
 332            let mut folds = iter::from_fn({
 333                let buffer = &buffer;
 334                move || {
 335                    let item = folds_cursor
 336                        .item()
 337                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 338                    folds_cursor.next(buffer);
 339                    item
 340                }
 341            })
 342            .peekable();
 343
 344            while folds
 345                .peek()
 346                .map_or(false, |fold| fold.start < edit.new_bytes.end)
 347            {
 348                let mut fold = folds.next().unwrap();
 349                let sum = new_transforms.summary();
 350
 351                assert!(fold.start >= sum.input.bytes);
 352
 353                while folds
 354                    .peek()
 355                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 356                {
 357                    let next_fold = folds.next().unwrap();
 358                    if next_fold.end > fold.end {
 359                        fold.end = next_fold.end;
 360                    }
 361                }
 362
 363                if fold.start > sum.input.bytes {
 364                    let text_summary = buffer.text_summary_for_range(sum.input.bytes..fold.start);
 365                    new_transforms.push(
 366                        Transform {
 367                            summary: TransformSummary {
 368                                output: text_summary.clone(),
 369                                input: text_summary,
 370                            },
 371                            output_text: None,
 372                        },
 373                        &(),
 374                    );
 375                }
 376
 377                if fold.end > fold.start {
 378                    let output_text = "";
 379                    let chars = output_text.chars().count() as u32;
 380                    let lines = super::Point::new(0, output_text.len() as u32);
 381                    new_transforms.push(
 382                        Transform {
 383                            summary: TransformSummary {
 384                                output: TextSummary {
 385                                    bytes: output_text.len(),
 386                                    lines,
 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_bytes.end {
 403                let text_summary =
 404                    buffer.text_summary_for_range(sum.input.bytes..edit.new_bytes.end);
 405                new_transforms.push(
 406                    Transform {
 407                        summary: TransformSummary {
 408                            output: text_summary.clone(),
 409                            input: text_summary,
 410                        },
 411                        output_text: None,
 412                    },
 413                    &(),
 414                );
 415            }
 416        }
 417
 418        new_transforms.push_tree(cursor.suffix(&()), &());
 419        if new_transforms.is_empty() {
 420            let text_summary = buffer.text_summary();
 421            new_transforms.push(
 422                Transform {
 423                    summary: TransformSummary {
 424                        output: text_summary.clone(),
 425                        input: text_summary,
 426                    },
 427                    output_text: None,
 428                },
 429                &(),
 430            );
 431        }
 432
 433        drop(cursor);
 434
 435        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 436        {
 437            let mut old_transforms = transforms.cursor::<(usize, FoldOffset)>();
 438            let mut new_transforms = new_transforms.cursor::<(usize, FoldOffset)>();
 439
 440            for mut edit in buffer_edits {
 441                old_transforms.seek(&edit.old_bytes.start, Bias::Left, &());
 442                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 443                    edit.old_bytes.start = old_transforms.start().0;
 444                }
 445                let old_start =
 446                    old_transforms.start().1 .0 + (edit.old_bytes.start - old_transforms.start().0);
 447
 448                old_transforms.seek_forward(&edit.old_bytes.end, Bias::Right, &());
 449                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 450                    old_transforms.next(&());
 451                    edit.old_bytes.end = old_transforms.start().0;
 452                }
 453                let old_end =
 454                    old_transforms.start().1 .0 + (edit.old_bytes.end - old_transforms.start().0);
 455
 456                new_transforms.seek(&edit.new_bytes.start, Bias::Left, &());
 457                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 458                    edit.new_bytes.start = new_transforms.start().0;
 459                }
 460                let new_start =
 461                    new_transforms.start().1 .0 + (edit.new_bytes.start - new_transforms.start().0);
 462
 463                new_transforms.seek_forward(&edit.new_bytes.end, Bias::Right, &());
 464                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 465                    new_transforms.next(&());
 466                    edit.new_bytes.end = new_transforms.start().0;
 467                }
 468                let new_end =
 469                    new_transforms.start().1 .0 + (edit.new_bytes.end - new_transforms.start().0);
 470
 471                fold_edits.push(FoldEdit {
 472                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 473                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 474                });
 475            }
 476
 477            consolidate_fold_edits(&mut fold_edits);
 478        }
 479
 480        *transforms = new_transforms;
 481        self.version.fetch_add(1, SeqCst);
 482        fold_edits
 483    }
 484}
 485
 486#[derive(Clone)]
 487pub struct Snapshot {
 488    transforms: SumTree<Transform>,
 489    folds: SumTree<Fold>,
 490    buffer_snapshot: language::Snapshot,
 491    pub version: usize,
 492}
 493
 494impl Snapshot {
 495    #[cfg(test)]
 496    pub fn text(&self) -> String {
 497        self.chunks_at(FoldOffset(0)).collect()
 498    }
 499
 500    #[cfg(test)]
 501    pub fn fold_count(&self) -> usize {
 502        self.folds.items(&self.buffer_snapshot).len()
 503    }
 504
 505    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 506        let mut summary = TextSummary::default();
 507
 508        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 509        cursor.seek(&range.start, Bias::Right, &());
 510        if let Some(transform) = cursor.item() {
 511            let start_in_transform = range.start.0 - cursor.start().0 .0;
 512            let end_in_transform = cmp::min(range.end, cursor.end(&()).0).0 - cursor.start().0 .0;
 513            if let Some(output_text) = transform.output_text {
 514                summary = TextSummary::from(
 515                    &output_text
 516                        [start_in_transform.column as usize..end_in_transform.column as usize],
 517                );
 518            } else {
 519                let buffer_start = cursor.start().1 + start_in_transform;
 520                let buffer_end = cursor.start().1 + end_in_transform;
 521                summary = self
 522                    .buffer_snapshot
 523                    .text_summary_for_range(buffer_start..buffer_end);
 524            }
 525        }
 526
 527        if range.end > cursor.end(&()).0 {
 528            cursor.next(&());
 529            summary += &cursor
 530                .summary::<_, TransformSummary>(&range.end, Bias::Right, &())
 531                .output;
 532            if let Some(transform) = cursor.item() {
 533                let end_in_transform = range.end.0 - cursor.start().0 .0;
 534                if let Some(output_text) = transform.output_text {
 535                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 536                } else {
 537                    let buffer_start = cursor.start().1;
 538                    let buffer_end = cursor.start().1 + end_in_transform;
 539                    summary += self
 540                        .buffer_snapshot
 541                        .text_summary_for_range(buffer_start..buffer_end);
 542                }
 543            }
 544        }
 545
 546        summary
 547    }
 548
 549    #[cfg(test)]
 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 chunks_at(&self, offset: FoldOffset) -> Chunks {
 627        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 628        transform_cursor.seek(&offset, Bias::Right, &());
 629        let overshoot = offset.0 - transform_cursor.start().0 .0;
 630        let buffer_offset = transform_cursor.start().1 + overshoot;
 631        Chunks {
 632            transform_cursor,
 633            buffer_offset,
 634            buffer_chunks: self
 635                .buffer_snapshot
 636                .text_for_range(buffer_offset..self.buffer_snapshot.len()),
 637        }
 638    }
 639
 640    pub fn highlighted_chunks(&mut self, range: Range<FoldOffset>) -> HighlightedChunks {
 641        let mut transform_cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 642
 643        transform_cursor.seek(&range.end, Bias::Right, &());
 644        let overshoot = range.end.0 - transform_cursor.start().0 .0;
 645        let buffer_end = transform_cursor.start().1 + overshoot;
 646
 647        transform_cursor.seek(&range.start, Bias::Right, &());
 648        let overshoot = range.start.0 - transform_cursor.start().0 .0;
 649        let buffer_start = transform_cursor.start().1 + overshoot;
 650
 651        HighlightedChunks {
 652            transform_cursor,
 653            buffer_offset: buffer_start,
 654            buffer_chunks: self
 655                .buffer_snapshot
 656                .highlighted_text_for_range(buffer_start..buffer_end),
 657            buffer_chunk: None,
 658        }
 659    }
 660
 661    pub fn chars_at<'a>(&'a self, point: FoldPoint) -> impl Iterator<Item = char> + 'a {
 662        let offset = point.to_offset(self);
 663        self.chunks_at(offset).flat_map(str::chars)
 664    }
 665
 666    #[cfg(test)]
 667    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 668        let mut cursor = self.transforms.cursor::<(FoldOffset, usize)>();
 669        cursor.seek(&offset, Bias::Right, &());
 670        if let Some(transform) = cursor.item() {
 671            let transform_start = cursor.start().0 .0;
 672            if transform.output_text.is_some() {
 673                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 674                    FoldOffset(transform_start)
 675                } else {
 676                    FoldOffset(cursor.end(&()).0 .0)
 677                }
 678            } else {
 679                let overshoot = offset.0 - transform_start;
 680                let buffer_offset = cursor.start().1 + overshoot;
 681                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 682                FoldOffset(
 683                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 684                        as usize,
 685                )
 686            }
 687        } else {
 688            FoldOffset(self.transforms.summary().output.bytes)
 689        }
 690    }
 691
 692    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 693        let mut cursor = self.transforms.cursor::<(FoldPoint, Point)>();
 694        cursor.seek(&point, Bias::Right, &());
 695        if let Some(transform) = cursor.item() {
 696            let transform_start = cursor.start().0 .0;
 697            if transform.output_text.is_some() {
 698                if point.0 == transform_start || matches!(bias, Bias::Left) {
 699                    FoldPoint(transform_start)
 700                } else {
 701                    FoldPoint(cursor.end(&()).0 .0)
 702                }
 703            } else {
 704                let overshoot = point.0 - transform_start;
 705                let buffer_position = cursor.start().1 + overshoot;
 706                let clipped_buffer_position =
 707                    self.buffer_snapshot.clip_point(buffer_position, bias);
 708                FoldPoint::new(
 709                    point.row(),
 710                    ((point.column() as i32) + clipped_buffer_position.column as i32
 711                        - buffer_position.column as i32) as u32,
 712                )
 713            }
 714        } else {
 715            FoldPoint(self.transforms.summary().output.lines)
 716        }
 717    }
 718}
 719
 720fn intersecting_folds<'a, T>(
 721    buffer: &'a buffer::Snapshot,
 722    folds: &'a SumTree<Fold>,
 723    range: Range<T>,
 724    inclusive: bool,
 725) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize>
 726where
 727    T: ToOffset,
 728{
 729    let start = buffer.anchor_before(range.start.to_offset(buffer));
 730    let end = buffer.anchor_after(range.end.to_offset(buffer));
 731    folds.filter::<_, usize>(
 732        move |summary| {
 733            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 734            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 735
 736            if inclusive {
 737                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 738            } else {
 739                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 740            }
 741        },
 742        buffer,
 743    )
 744}
 745
 746fn consolidate_buffer_edits(edits: &mut Vec<buffer::Edit>) {
 747    edits.sort_unstable_by(|a, b| {
 748        a.old_bytes
 749            .start
 750            .cmp(&b.old_bytes.start)
 751            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 752    });
 753
 754    let mut i = 1;
 755    while i < edits.len() {
 756        let edit = edits[i].clone();
 757        let prev_edit = &mut edits[i - 1];
 758        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 759            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 760            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 761            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 762            edits.remove(i);
 763            continue;
 764        }
 765        i += 1;
 766    }
 767}
 768
 769fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 770    edits.sort_unstable_by(|a, b| {
 771        a.old_bytes
 772            .start
 773            .cmp(&b.old_bytes.start)
 774            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 775    });
 776
 777    let mut i = 1;
 778    while i < edits.len() {
 779        let edit = edits[i].clone();
 780        let prev_edit = &mut edits[i - 1];
 781        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 782            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 783            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 784            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 785            edits.remove(i);
 786            continue;
 787        }
 788        i += 1;
 789    }
 790}
 791
 792#[derive(Clone, Debug, Default, Eq, PartialEq)]
 793struct Transform {
 794    summary: TransformSummary,
 795    output_text: Option<&'static str>,
 796}
 797
 798impl Transform {
 799    fn is_fold(&self) -> bool {
 800        self.output_text.is_some()
 801    }
 802}
 803
 804#[derive(Clone, Debug, Default, Eq, PartialEq)]
 805struct TransformSummary {
 806    output: TextSummary,
 807    input: TextSummary,
 808}
 809
 810impl sum_tree::Item for Transform {
 811    type Summary = TransformSummary;
 812
 813    fn summary(&self) -> Self::Summary {
 814        self.summary.clone()
 815    }
 816}
 817
 818impl sum_tree::Summary for TransformSummary {
 819    type Context = ();
 820
 821    fn add_summary(&mut self, other: &Self, _: &()) {
 822        self.input += &other.input;
 823        self.output += &other.output;
 824    }
 825}
 826
 827#[derive(Clone, Debug)]
 828struct Fold(Range<Anchor>);
 829
 830impl Default for Fold {
 831    fn default() -> Self {
 832        Self(Anchor::min()..Anchor::max())
 833    }
 834}
 835
 836impl sum_tree::Item for Fold {
 837    type Summary = FoldSummary;
 838
 839    fn summary(&self) -> Self::Summary {
 840        FoldSummary {
 841            start: self.0.start.clone(),
 842            end: self.0.end.clone(),
 843            min_start: self.0.start.clone(),
 844            max_end: self.0.end.clone(),
 845            count: 1,
 846        }
 847    }
 848}
 849
 850#[derive(Clone, Debug)]
 851struct FoldSummary {
 852    start: Anchor,
 853    end: Anchor,
 854    min_start: Anchor,
 855    max_end: Anchor,
 856    count: usize,
 857}
 858
 859impl Default for FoldSummary {
 860    fn default() -> Self {
 861        Self {
 862            start: Anchor::min(),
 863            end: Anchor::max(),
 864            min_start: Anchor::max(),
 865            max_end: Anchor::min(),
 866            count: 0,
 867        }
 868    }
 869}
 870
 871impl sum_tree::Summary for FoldSummary {
 872    type Context = buffer::Snapshot;
 873
 874    fn add_summary(&mut self, other: &Self, buffer: &buffer::Snapshot) {
 875        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 876            self.min_start = other.min_start.clone();
 877        }
 878        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 879            self.max_end = other.max_end.clone();
 880        }
 881
 882        #[cfg(debug_assertions)]
 883        {
 884            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 885            assert!(start_comparison <= Ordering::Equal);
 886            if start_comparison == Ordering::Equal {
 887                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 888            }
 889        }
 890
 891        self.start = other.start.clone();
 892        self.end = other.end.clone();
 893        self.count += other.count;
 894    }
 895}
 896
 897impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 898    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 899        self.0.start = summary.start.clone();
 900        self.0.end = summary.end.clone();
 901    }
 902}
 903
 904impl<'a> sum_tree::SeekTarget<'a, FoldSummary, Fold> for Fold {
 905    fn cmp(&self, other: &Self, buffer: &buffer::Snapshot) -> Ordering {
 906        self.0.cmp(&other.0, buffer).unwrap()
 907    }
 908}
 909
 910impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 911    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 912        *self += summary.count;
 913    }
 914}
 915
 916pub struct BufferRows<'a> {
 917    cursor: Cursor<'a, Transform, (FoldPoint, Point)>,
 918    fold_point: FoldPoint,
 919}
 920
 921impl<'a> Iterator for BufferRows<'a> {
 922    type Item = u32;
 923
 924    fn next(&mut self) -> Option<Self::Item> {
 925        while self.fold_point > self.cursor.end(&()).0 {
 926            self.cursor.next(&());
 927            if self.cursor.item().is_none() {
 928                // TODO: Return a bool from next?
 929                break;
 930            }
 931        }
 932
 933        if self.cursor.item().is_some() {
 934            let overshoot = self.fold_point.0 - self.cursor.start().0 .0;
 935            let buffer_point = self.cursor.start().1 + overshoot;
 936            *self.fold_point.row_mut() += 1;
 937            Some(buffer_point.row)
 938        } else {
 939            None
 940        }
 941    }
 942}
 943
 944pub struct Chunks<'a> {
 945    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 946    buffer_chunks: buffer::Chunks<'a>,
 947    buffer_offset: usize,
 948}
 949
 950impl<'a> Iterator for Chunks<'a> {
 951    type Item = &'a str;
 952
 953    fn next(&mut self) -> Option<Self::Item> {
 954        let transform = if let Some(item) = self.transform_cursor.item() {
 955            item
 956        } else {
 957            return None;
 958        };
 959
 960        // If we're in a fold, then return the fold's display text and
 961        // advance the transform and buffer cursors to the end of the fold.
 962        if let Some(output_text) = transform.output_text {
 963            self.buffer_offset += transform.summary.input.bytes;
 964            self.buffer_chunks.seek(self.buffer_offset);
 965
 966            while self.buffer_offset >= self.transform_cursor.end(&()).1
 967                && self.transform_cursor.item().is_some()
 968            {
 969                self.transform_cursor.next(&());
 970            }
 971
 972            return Some(output_text);
 973        }
 974
 975        // Otherwise, take a chunk from the buffer's text.
 976        if let Some(mut chunk) = self.buffer_chunks.peek() {
 977            let offset_in_chunk = self.buffer_offset - self.buffer_chunks.offset();
 978            chunk = &chunk[offset_in_chunk..];
 979
 980            // Truncate the chunk so that it ends at the next fold.
 981            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
 982            if chunk.len() >= region_end {
 983                chunk = &chunk[0..region_end];
 984                self.transform_cursor.next(&());
 985            } else {
 986                self.buffer_chunks.next();
 987            }
 988
 989            self.buffer_offset += chunk.len();
 990            return Some(chunk);
 991        }
 992
 993        None
 994    }
 995}
 996
 997pub struct HighlightedChunks<'a> {
 998    transform_cursor: Cursor<'a, Transform, (FoldOffset, usize)>,
 999    buffer_chunks: language::HighlightedChunks<'a>,
1000    buffer_chunk: Option<(usize, HighlightedChunk<'a>)>,
1001    buffer_offset: usize,
1002}
1003
1004impl<'a> Iterator for HighlightedChunks<'a> {
1005    type Item = HighlightedChunk<'a>;
1006
1007    fn next(&mut self) -> Option<Self::Item> {
1008        let transform = if let Some(item) = self.transform_cursor.item() {
1009            item
1010        } else {
1011            return None;
1012        };
1013
1014        // If we're in a fold, then return the fold's display text and
1015        // advance the transform and buffer cursors to the end of the fold.
1016        if let Some(output_text) = transform.output_text {
1017            self.buffer_chunk.take();
1018            self.buffer_offset += transform.summary.input.bytes;
1019            self.buffer_chunks.seek(self.buffer_offset);
1020
1021            while self.buffer_offset >= self.transform_cursor.end(&()).1
1022                && self.transform_cursor.item().is_some()
1023            {
1024                self.transform_cursor.next(&());
1025            }
1026
1027            return Some(HighlightedChunk {
1028                text: output_text,
1029                highlight_id: HighlightId::default(),
1030                diagnostic: None,
1031            });
1032        }
1033
1034        // Retrieve a chunk from the current location in the buffer.
1035        if self.buffer_chunk.is_none() {
1036            let chunk_offset = self.buffer_chunks.offset();
1037            self.buffer_chunk = self.buffer_chunks.next().map(|chunk| (chunk_offset, chunk));
1038        }
1039
1040        // Otherwise, take a chunk from the buffer's text.
1041        if let Some((chunk_offset, mut chunk)) = self.buffer_chunk {
1042            let offset_in_chunk = self.buffer_offset - chunk_offset;
1043            chunk.text = &chunk.text[offset_in_chunk..];
1044
1045            // Truncate the chunk so that it ends at the next fold.
1046            let region_end = self.transform_cursor.end(&()).1 - self.buffer_offset;
1047            if chunk.text.len() >= region_end {
1048                chunk.text = &chunk.text[0..region_end];
1049                self.transform_cursor.next(&());
1050            } else {
1051                self.buffer_chunk.take();
1052            }
1053
1054            self.buffer_offset += chunk.text.len();
1055            return Some(chunk);
1056        }
1057
1058        None
1059    }
1060}
1061
1062impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1063    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1064        self.0 += &summary.output.lines;
1065    }
1066}
1067
1068#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1069pub struct FoldOffset(pub usize);
1070
1071impl FoldOffset {
1072    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1073        let mut cursor = snapshot
1074            .transforms
1075            .cursor::<(FoldOffset, TransformSummary)>();
1076        cursor.seek(self, Bias::Right, &());
1077        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1078            Point::new(0, (self.0 - cursor.start().0 .0) as u32)
1079        } else {
1080            let buffer_offset = cursor.start().1.input.bytes + self.0 - cursor.start().0 .0;
1081            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1082            buffer_point - cursor.start().1.input.lines
1083        };
1084        FoldPoint(cursor.start().1.output.lines + overshoot)
1085    }
1086}
1087
1088impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1089    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1090        self.0 += &summary.output.bytes;
1091    }
1092}
1093
1094impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1095    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1096        *self += &summary.input.lines;
1097    }
1098}
1099
1100impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1101    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1102        *self += &summary.input.bytes;
1103    }
1104}
1105
1106#[derive(Clone, Debug, PartialEq, Eq)]
1107pub struct FoldEdit {
1108    pub old_bytes: Range<FoldOffset>,
1109    pub new_bytes: Range<FoldOffset>,
1110}
1111
1112#[cfg(test)]
1113impl FoldEdit {
1114    pub fn delta(&self) -> isize {
1115        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1116    }
1117
1118    pub fn deleted_bytes(&self) -> usize {
1119        self.old_bytes.end.0 - self.old_bytes.start.0
1120    }
1121
1122    pub fn inserted_bytes(&self) -> usize {
1123        self.new_bytes.end.0 - self.new_bytes.start.0
1124    }
1125}
1126
1127#[cfg(test)]
1128mod tests {
1129    use super::*;
1130    use crate::{test::sample_text, ToPoint};
1131    use buffer::RandomCharIter;
1132    use rand::prelude::*;
1133    use std::{env, mem};
1134    use Bias::{Left, Right};
1135
1136    #[gpui::test]
1137    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1138        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1139        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1140
1141        let (mut writer, _, _) = map.write(cx.as_ref());
1142        let (snapshot2, edits) = writer.fold(
1143            vec![
1144                Point::new(0, 2)..Point::new(2, 2),
1145                Point::new(2, 4)..Point::new(4, 1),
1146            ],
1147            cx.as_ref(),
1148        );
1149        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1150        assert_eq!(
1151            edits,
1152            &[
1153                FoldEdit {
1154                    old_bytes: FoldOffset(2)..FoldOffset(16),
1155                    new_bytes: FoldOffset(2)..FoldOffset(5),
1156                },
1157                FoldEdit {
1158                    old_bytes: FoldOffset(18)..FoldOffset(29),
1159                    new_bytes: FoldOffset(7)..FoldOffset(10)
1160                },
1161            ]
1162        );
1163
1164        buffer.update(cx, |buffer, cx| {
1165            buffer.edit(
1166                vec![
1167                    Point::new(0, 0)..Point::new(0, 1),
1168                    Point::new(2, 3)..Point::new(2, 3),
1169                ],
1170                "123",
1171                cx,
1172            );
1173        });
1174        let (snapshot3, edits) = map.read(cx.as_ref());
1175        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1176        assert_eq!(
1177            edits,
1178            &[
1179                FoldEdit {
1180                    old_bytes: FoldOffset(0)..FoldOffset(1),
1181                    new_bytes: FoldOffset(0)..FoldOffset(3),
1182                },
1183                FoldEdit {
1184                    old_bytes: FoldOffset(6)..FoldOffset(6),
1185                    new_bytes: FoldOffset(8)..FoldOffset(11),
1186                },
1187            ]
1188        );
1189
1190        buffer.update(cx, |buffer, cx| {
1191            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx)
1192        });
1193        let (snapshot4, _) = map.read(cx.as_ref());
1194        assert_eq!(snapshot4.text(), "123a…c123456eee");
1195
1196        let (mut writer, _, _) = map.write(cx.as_ref());
1197        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), cx.as_ref());
1198        let (snapshot5, _) = map.read(cx.as_ref());
1199        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1200    }
1201
1202    #[gpui::test]
1203    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1204        let buffer = cx.add_model(|cx| Buffer::new(0, "abcdefghijkl", cx));
1205
1206        {
1207            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1208
1209            let (mut writer, _, _) = map.write(cx.as_ref());
1210            writer.fold(vec![5..8], cx.as_ref());
1211            let (snapshot, _) = map.read(cx.as_ref());
1212            assert_eq!(snapshot.text(), "abcde…ijkl");
1213
1214            // Create an fold adjacent to the start of the first fold.
1215            let (mut writer, _, _) = map.write(cx.as_ref());
1216            writer.fold(vec![0..1, 2..5], cx.as_ref());
1217            let (snapshot, _) = map.read(cx.as_ref());
1218            assert_eq!(snapshot.text(), "…b…ijkl");
1219
1220            // Create an fold adjacent to the end of the first fold.
1221            let (mut writer, _, _) = map.write(cx.as_ref());
1222            writer.fold(vec![11..11, 8..10], cx.as_ref());
1223            let (snapshot, _) = map.read(cx.as_ref());
1224            assert_eq!(snapshot.text(), "…b…kl");
1225        }
1226
1227        {
1228            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1229
1230            // Create two adjacent folds.
1231            let (mut writer, _, _) = map.write(cx.as_ref());
1232            writer.fold(vec![0..2, 2..5], cx.as_ref());
1233            let (snapshot, _) = map.read(cx.as_ref());
1234            assert_eq!(snapshot.text(), "…fghijkl");
1235
1236            // Edit within one of the folds.
1237            buffer.update(cx, |buffer, cx| buffer.edit(vec![0..1], "12345", cx));
1238            let (snapshot, _) = map.read(cx.as_ref());
1239            assert_eq!(snapshot.text(), "12345…fghijkl");
1240        }
1241    }
1242
1243    #[gpui::test]
1244    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1245        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1246        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1247        let (mut writer, _, _) = map.write(cx.as_ref());
1248        writer.fold(
1249            vec![
1250                Point::new(0, 2)..Point::new(2, 2),
1251                Point::new(0, 4)..Point::new(1, 0),
1252                Point::new(1, 2)..Point::new(3, 2),
1253                Point::new(3, 1)..Point::new(4, 1),
1254            ],
1255            cx.as_ref(),
1256        );
1257        let (snapshot, _) = map.read(cx.as_ref());
1258        assert_eq!(snapshot.text(), "aa…eeeee");
1259    }
1260
1261    #[gpui::test]
1262    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1263        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1264        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1265
1266        let (mut writer, _, _) = map.write(cx.as_ref());
1267        writer.fold(
1268            vec![
1269                Point::new(0, 2)..Point::new(2, 2),
1270                Point::new(3, 1)..Point::new(4, 1),
1271            ],
1272            cx.as_ref(),
1273        );
1274        let (snapshot, _) = map.read(cx.as_ref());
1275        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1276
1277        buffer.update(cx, |buffer, cx| {
1278            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx)
1279        });
1280        let (snapshot, _) = map.read(cx.as_ref());
1281        assert_eq!(snapshot.text(), "aa…eeeee");
1282    }
1283
1284    #[gpui::test]
1285    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1286        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1287        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1288        let buffer = buffer.read(cx);
1289
1290        let (mut writer, _, _) = map.write(cx.as_ref());
1291        writer.fold(
1292            vec![
1293                Point::new(0, 2)..Point::new(2, 2),
1294                Point::new(0, 4)..Point::new(1, 0),
1295                Point::new(1, 2)..Point::new(3, 2),
1296                Point::new(3, 1)..Point::new(4, 1),
1297            ],
1298            cx.as_ref(),
1299        );
1300        let (snapshot, _) = map.read(cx.as_ref());
1301        let fold_ranges = snapshot
1302            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1303            .map(|fold| fold.start.to_point(buffer)..fold.end.to_point(buffer))
1304            .collect::<Vec<_>>();
1305        assert_eq!(
1306            fold_ranges,
1307            vec![
1308                Point::new(0, 2)..Point::new(2, 2),
1309                Point::new(1, 2)..Point::new(3, 2)
1310            ]
1311        );
1312    }
1313
1314    #[gpui::test(iterations = 100)]
1315    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1316        let operations = env::var("OPERATIONS")
1317            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1318            .unwrap_or(10);
1319
1320        let buffer = cx.add_model(|cx| {
1321            let len = rng.gen_range(0..10);
1322            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1323            Buffer::new(0, text, cx)
1324        });
1325        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1326
1327        let (mut initial_snapshot, _) = map.read(cx.as_ref());
1328        let mut snapshot_edits = Vec::new();
1329
1330        for _ in 0..operations {
1331            log::info!("text: {:?}", buffer.read(cx).text());
1332            match rng.gen_range(0..=100) {
1333                0..=59 => {
1334                    snapshot_edits.extend(map.randomly_mutate(&mut rng, cx.as_ref()));
1335                }
1336                _ => {
1337                    let edits = buffer.update(cx, |buffer, _| {
1338                        let start_version = buffer.version.clone();
1339                        let edit_count = rng.gen_range(1..=5);
1340                        buffer.randomly_edit(&mut rng, edit_count);
1341                        buffer.edits_since(start_version).collect::<Vec<_>>()
1342                    });
1343                    log::info!("editing {:?}", edits);
1344                }
1345            }
1346
1347            let buffer = map.buffer.read(cx).snapshot();
1348            let mut expected_text: String = buffer.text().into();
1349            let mut expected_buffer_rows = Vec::new();
1350            let mut next_row = buffer.max_point().row;
1351            for fold_range in map.merged_fold_ranges(cx.as_ref()).into_iter().rev() {
1352                let fold_start = buffer.point_for_offset(fold_range.start).unwrap();
1353                let fold_end = buffer.point_for_offset(fold_range.end).unwrap();
1354                expected_buffer_rows.extend((fold_end.row + 1..=next_row).rev());
1355                next_row = fold_start.row;
1356
1357                expected_text.replace_range(fold_range.start..fold_range.end, "");
1358            }
1359            expected_buffer_rows.extend((0..=next_row).rev());
1360            expected_buffer_rows.reverse();
1361
1362            let (snapshot, edits) = map.read(cx.as_ref());
1363            assert_eq!(snapshot.text(), expected_text);
1364            snapshot_edits.push((snapshot.clone(), edits));
1365
1366            for (output_row, line) in expected_text.lines().enumerate() {
1367                let line_len = snapshot.line_len(output_row as u32);
1368                assert_eq!(line_len, line.len() as u32);
1369            }
1370
1371            let longest_row = snapshot.longest_row();
1372            let longest_char_column = expected_text
1373                .split('\n')
1374                .nth(longest_row as usize)
1375                .unwrap()
1376                .chars()
1377                .count();
1378            let mut fold_point = FoldPoint::new(0, 0);
1379            let mut fold_offset = FoldOffset(0);
1380            let mut char_column = 0;
1381            for c in expected_text.chars() {
1382                let buffer_point = fold_point.to_buffer_point(&snapshot);
1383                let buffer_offset = buffer_point.to_offset(&buffer);
1384                assert_eq!(
1385                    buffer_point.to_fold_point(&snapshot, Right),
1386                    fold_point,
1387                    "{:?} -> fold point",
1388                    buffer_point,
1389                );
1390                assert_eq!(
1391                    fold_point.to_buffer_offset(&snapshot),
1392                    buffer_offset,
1393                    "fold_point.to_buffer_offset({:?})",
1394                    fold_point,
1395                );
1396                assert_eq!(
1397                    fold_point.to_offset(&snapshot),
1398                    fold_offset,
1399                    "fold_point.to_offset({:?})",
1400                    fold_point,
1401                );
1402
1403                if c == '\n' {
1404                    *fold_point.row_mut() += 1;
1405                    *fold_point.column_mut() = 0;
1406                    char_column = 0;
1407                } else {
1408                    *fold_point.column_mut() += c.len_utf8() as u32;
1409                    char_column += 1;
1410                }
1411                fold_offset.0 += c.len_utf8();
1412                if char_column > longest_char_column {
1413                    panic!(
1414                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1415                        longest_row,
1416                        longest_char_column,
1417                        fold_point.row(),
1418                        char_column
1419                    );
1420                }
1421            }
1422
1423            for _ in 0..5 {
1424                let offset = snapshot
1425                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1426                assert_eq!(
1427                    snapshot.chunks_at(offset).collect::<String>(),
1428                    &expected_text[offset.0..],
1429                );
1430            }
1431
1432            for (idx, buffer_row) in expected_buffer_rows.iter().enumerate() {
1433                let fold_row = Point::new(*buffer_row, 0)
1434                    .to_fold_point(&snapshot, Right)
1435                    .row();
1436                assert_eq!(
1437                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1438                    expected_buffer_rows[idx..],
1439                );
1440            }
1441
1442            for fold_range in map.merged_fold_ranges(cx.as_ref()) {
1443                let fold_point = fold_range
1444                    .start
1445                    .to_point(&buffer)
1446                    .to_fold_point(&snapshot, Right);
1447                assert!(snapshot.is_line_folded(fold_point.row()));
1448            }
1449
1450            for _ in 0..5 {
1451                let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1452                let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1453                let expected_folds = map
1454                    .folds
1455                    .items(&buffer)
1456                    .into_iter()
1457                    .filter(|fold| {
1458                        let start = buffer.anchor_before(start);
1459                        let end = buffer.anchor_after(end);
1460                        start.cmp(&fold.0.end, &buffer).unwrap() == Ordering::Less
1461                            && end.cmp(&fold.0.start, &buffer).unwrap() == Ordering::Greater
1462                    })
1463                    .map(|fold| fold.0)
1464                    .collect::<Vec<_>>();
1465
1466                assert_eq!(
1467                    snapshot
1468                        .folds_in_range(start..end)
1469                        .cloned()
1470                        .collect::<Vec<_>>(),
1471                    expected_folds
1472                );
1473            }
1474
1475            let text = snapshot.text();
1476            for _ in 0..5 {
1477                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1478                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1479                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1480                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1481                let mut start =
1482                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1483                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1484                if start > end {
1485                    mem::swap(&mut start, &mut end);
1486                }
1487
1488                let lines = start..end;
1489                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1490                assert_eq!(
1491                    snapshot.text_summary_for_range(lines),
1492                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1493                )
1494            }
1495
1496            let mut text = initial_snapshot.text();
1497            for (snapshot, edits) in snapshot_edits.drain(..) {
1498                let new_text = snapshot.text();
1499                let mut delta = 0isize;
1500                for edit in edits {
1501                    let old_bytes = ((edit.old_bytes.start.0 as isize) + delta) as usize
1502                        ..((edit.old_bytes.end.0 as isize) + delta) as usize;
1503                    let new_bytes = edit.new_bytes.start.0..edit.new_bytes.end.0;
1504                    delta += edit.delta();
1505                    text.replace_range(old_bytes, &new_text[new_bytes]);
1506                }
1507
1508                assert_eq!(text, new_text);
1509                initial_snapshot = snapshot;
1510            }
1511        }
1512    }
1513
1514    #[gpui::test]
1515    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1516        let text = sample_text(6, 6) + "\n";
1517        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1518
1519        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1520
1521        let (mut writer, _, _) = map.write(cx.as_ref());
1522        writer.fold(
1523            vec![
1524                Point::new(0, 2)..Point::new(2, 2),
1525                Point::new(3, 1)..Point::new(4, 1),
1526            ],
1527            cx.as_ref(),
1528        );
1529
1530        let (snapshot, _) = map.read(cx.as_ref());
1531        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1532        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), [0, 3, 5, 6]);
1533        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [6]);
1534    }
1535
1536    impl FoldMap {
1537        fn merged_fold_ranges(&self, cx: &AppContext) -> Vec<Range<usize>> {
1538            let buffer = self.buffer.read(cx).snapshot();
1539            let mut folds = self.folds.items(&buffer);
1540            // Ensure sorting doesn't change how folds get merged and displayed.
1541            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1542            let mut fold_ranges = folds
1543                .iter()
1544                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1545                .peekable();
1546
1547            let mut merged_ranges = Vec::new();
1548            while let Some(mut fold_range) = fold_ranges.next() {
1549                while let Some(next_range) = fold_ranges.peek() {
1550                    if fold_range.end >= next_range.start {
1551                        if next_range.end > fold_range.end {
1552                            fold_range.end = next_range.end;
1553                        }
1554                        fold_ranges.next();
1555                    } else {
1556                        break;
1557                    }
1558                }
1559                if fold_range.end > fold_range.start {
1560                    merged_ranges.push(fold_range);
1561                }
1562            }
1563            merged_ranges
1564        }
1565
1566        pub fn randomly_mutate(
1567            &mut self,
1568            rng: &mut impl Rng,
1569            cx: &AppContext,
1570        ) -> Vec<(Snapshot, Vec<FoldEdit>)> {
1571            let mut snapshot_edits = Vec::new();
1572            match rng.gen_range(0..=100) {
1573                0..=39 if !self.folds.is_empty() => {
1574                    let buffer = self.buffer.read(cx);
1575                    let mut to_unfold = Vec::new();
1576                    for _ in 0..rng.gen_range(1..=3) {
1577                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1578                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1579                        to_unfold.push(start..end);
1580                    }
1581                    log::info!("unfolding {:?}", to_unfold);
1582                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1583                    snapshot_edits.push((snapshot, edits));
1584                    let (snapshot, edits) = writer.fold(to_unfold, cx.as_ref());
1585                    snapshot_edits.push((snapshot, edits));
1586                }
1587                _ => {
1588                    let buffer = self.buffer.read(cx);
1589                    let mut to_fold = Vec::new();
1590                    for _ in 0..rng.gen_range(1..=2) {
1591                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1592                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1593                        to_fold.push(start..end);
1594                    }
1595                    log::info!("folding {:?}", to_fold);
1596                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1597                    snapshot_edits.push((snapshot, edits));
1598                    let (snapshot, edits) = writer.fold(to_fold, cx.as_ref());
1599                    snapshot_edits.push((snapshot, edits));
1600                }
1601            }
1602            snapshot_edits
1603        }
1604    }
1605}