fold_map.rs

   1use super::{
   2    buffer::{AnchorRangeExt, TextSummary},
   3    Anchor, Buffer, Point, ToOffset,
   4};
   5use crate::{editor::buffer, settings::HighlightId, time, util::Bias};
   6use gpui::{
   7    sum_tree::{self, Cursor, FilterCursor, SumTree},
   8    AppContext, ModelHandle,
   9};
  10use parking_lot::Mutex;
  11use std::{
  12    cmp::{self, Ordering},
  13    iter, mem,
  14    ops::Range,
  15    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  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.seek_start().0;
  47        *cursor.sum_start() + 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.seek_start().0;
  54        snapshot
  55            .buffer_snapshot
  56            .to_offset(*cursor.sum_start() + overshoot)
  57    }
  58
  59    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  60        let mut cursor = snapshot.transforms.cursor::<FoldPoint, TransformSummary>();
  61        cursor.seek(self, Bias::Right, &());
  62        let overshoot = self.0 - cursor.sum_start().output.lines;
  63        let mut offset = cursor.sum_start().output.bytes;
  64        if !overshoot.is_zero() {
  65            let transform = cursor.item().expect("display point out of range");
  66            assert!(transform.output_text.is_none());
  67            let end_buffer_offset = snapshot
  68                .buffer_snapshot
  69                .to_offset(cursor.sum_start().input.lines + overshoot);
  70            offset += end_buffer_offset - cursor.sum_start().input.bytes;
  71        }
  72        FoldOffset(offset)
  73    }
  74}
  75
  76impl Point {
  77    pub fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  78        let mut cursor = snapshot.transforms.cursor::<Point, FoldPoint>();
  79        cursor.seek(self, Bias::Right, &());
  80        if cursor.item().map_or(false, |t| t.is_fold()) {
  81            if bias == Bias::Left || *self == *cursor.seek_start() {
  82                *cursor.sum_start()
  83            } else {
  84                cursor.sum_end(&())
  85            }
  86        } else {
  87            let overshoot = *self - cursor.seek_start();
  88            FoldPoint(cmp::min(
  89                cursor.sum_start().0 + overshoot,
  90                cursor.sum_end(&()).0,
  91            ))
  92        }
  93    }
  94}
  95
  96pub struct FoldMapWriter<'a>(&'a mut FoldMap);
  97
  98impl<'a> FoldMapWriter<'a> {
  99    pub fn fold<T: ToOffset>(
 100        &mut self,
 101        ranges: impl IntoIterator<Item = Range<T>>,
 102        cx: &AppContext,
 103    ) -> (Snapshot, Vec<FoldEdit>) {
 104        let mut edits = Vec::new();
 105        let mut folds = Vec::new();
 106        let buffer = self.0.buffer.read(cx).snapshot();
 107        for range in ranges.into_iter() {
 108            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 109            if range.start != range.end {
 110                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 111                folds.push(fold);
 112                edits.push(buffer::Edit {
 113                    old_bytes: range.clone(),
 114                    new_bytes: range.clone(),
 115                    ..Default::default()
 116                });
 117            }
 118        }
 119
 120        folds.sort_unstable_by(|a, b| sum_tree::SeekDimension::cmp(a, b, &buffer));
 121
 122        self.0.folds = {
 123            let mut new_tree = SumTree::new();
 124            let mut cursor = self.0.folds.cursor::<_, ()>();
 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(buffer::Edit {
 158                    old_bytes: offset_range.clone(),
 159                    new_bytes: offset_range,
 160                    ..Default::default()
 161                });
 162                fold_ixs_to_delete.push(*folds_cursor.start());
 163                folds_cursor.next(&buffer);
 164            }
 165        }
 166
 167        fold_ixs_to_delete.sort_unstable();
 168        fold_ixs_to_delete.dedup();
 169
 170        self.0.folds = {
 171            let mut cursor = self.0.folds.cursor::<_, ()>();
 172            let mut folds = SumTree::new();
 173            for fold_ix in fold_ixs_to_delete {
 174                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 175                cursor.next(&buffer);
 176            }
 177            folds.push_tree(cursor.suffix(&buffer), &buffer);
 178            folds
 179        };
 180
 181        consolidate_buffer_edits(&mut edits);
 182        let edits = self.0.apply_edits(edits, cx);
 183        let snapshot = Snapshot {
 184            transforms: self.0.transforms.lock().clone(),
 185            folds: self.0.folds.clone(),
 186            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 187            version: self.0.version.load(SeqCst),
 188        };
 189        (snapshot, edits)
 190    }
 191}
 192
 193pub struct FoldMap {
 194    buffer: ModelHandle<Buffer>,
 195    transforms: Mutex<SumTree<Transform>>,
 196    folds: SumTree<Fold>,
 197    last_sync: Mutex<SyncState>,
 198    version: AtomicUsize,
 199}
 200
 201#[derive(Clone)]
 202struct SyncState {
 203    version: time::Global,
 204    is_parsing: bool,
 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                is_parsing: buffer.is_parsing(),
 226            }),
 227            version: AtomicUsize::new(0),
 228        };
 229        let (snapshot, _) = this.read(cx);
 230        (this, snapshot)
 231    }
 232
 233    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 234        let edits = self.sync(cx);
 235        self.check_invariants(cx);
 236        let snapshot = Snapshot {
 237            transforms: self.transforms.lock().clone(),
 238            folds: self.folds.clone(),
 239            buffer_snapshot: self.buffer.read(cx).snapshot(),
 240            version: self.version.load(SeqCst),
 241        };
 242        (snapshot, edits)
 243    }
 244
 245    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 246        let (snapshot, edits) = self.read(cx);
 247        (FoldMapWriter(self), snapshot, edits)
 248    }
 249
 250    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 251        let buffer = self.buffer.read(cx);
 252        let last_sync = mem::replace(
 253            &mut *self.last_sync.lock(),
 254            SyncState {
 255                version: buffer.version(),
 256                is_parsing: buffer.is_parsing(),
 257            },
 258        );
 259        let edits = buffer
 260            .edits_since(last_sync.version)
 261            .map(Into::into)
 262            .collect::<Vec<_>>();
 263        if edits.is_empty() {
 264            if last_sync.is_parsing != buffer.is_parsing() {
 265                self.version.fetch_add(1, SeqCst);
 266            }
 267            Vec::new()
 268        } else {
 269            self.apply_edits(edits, cx)
 270        }
 271    }
 272
 273    fn check_invariants(&self, cx: &AppContext) {
 274        if cfg!(test) {
 275            let buffer = self.buffer.read(cx);
 276            assert_eq!(
 277                self.transforms.lock().summary().input.bytes,
 278                buffer.len(),
 279                "transform tree does not match buffer's length"
 280            );
 281        }
 282    }
 283
 284    fn apply_edits(&self, buffer_edits: Vec<buffer::Edit>, cx: &AppContext) -> Vec<FoldEdit> {
 285        let buffer = self.buffer.read(cx).snapshot();
 286        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 287
 288        let mut new_transforms = SumTree::new();
 289        let mut transforms = self.transforms.lock();
 290        let mut cursor = transforms.cursor::<usize, ()>();
 291        cursor.seek(&0, Bias::Right, &());
 292
 293        while let Some(mut edit) = buffer_edits_iter.next() {
 294            new_transforms.push_tree(cursor.slice(&edit.old_bytes.start, Bias::Left, &()), &());
 295            edit.new_bytes.start -= edit.old_bytes.start - cursor.seek_start();
 296            edit.old_bytes.start = *cursor.seek_start();
 297
 298            cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 299            cursor.next(&());
 300
 301            let mut delta = edit.delta();
 302            loop {
 303                edit.old_bytes.end = *cursor.seek_start();
 304
 305                if let Some(next_edit) = buffer_edits_iter.peek() {
 306                    if next_edit.old_bytes.start > edit.old_bytes.end {
 307                        break;
 308                    }
 309
 310                    let next_edit = buffer_edits_iter.next().unwrap();
 311                    delta += next_edit.delta();
 312
 313                    if next_edit.old_bytes.end >= edit.old_bytes.end {
 314                        edit.old_bytes.end = next_edit.old_bytes.end;
 315                        cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 316                        cursor.next(&());
 317                    }
 318                } else {
 319                    break;
 320                }
 321            }
 322
 323            edit.new_bytes.end =
 324                ((edit.new_bytes.start + edit.deleted_bytes()) as isize + delta) as usize;
 325
 326            let anchor = buffer.anchor_before(edit.new_bytes.start);
 327            let mut folds_cursor = self.folds.cursor::<_, ()>();
 328            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 329
 330            let mut folds = iter::from_fn({
 331                let buffer = &buffer;
 332                move || {
 333                    let item = folds_cursor
 334                        .item()
 335                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 336                    folds_cursor.next(buffer);
 337                    item
 338                }
 339            })
 340            .peekable();
 341
 342            while folds
 343                .peek()
 344                .map_or(false, |fold| fold.start < edit.new_bytes.end)
 345            {
 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 = super::Point::new(0, output_text.len() as u32);
 379                    new_transforms.push(
 380                        Transform {
 381                            summary: TransformSummary {
 382                                output: TextSummary {
 383                                    bytes: output_text.len(),
 384                                    lines,
 385                                    first_line_chars: chars,
 386                                    last_line_chars: chars,
 387                                    longest_row: 0,
 388                                    longest_row_chars: chars,
 389                                },
 390                                input: buffer.text_summary_for_range(fold.start..fold.end),
 391                            },
 392                            output_text: Some(output_text),
 393                        },
 394                        &(),
 395                    );
 396                }
 397            }
 398
 399            let sum = new_transforms.summary();
 400            if sum.input.bytes < edit.new_bytes.end {
 401                let text_summary =
 402                    buffer.text_summary_for_range(sum.input.bytes..edit.new_bytes.end);
 403                new_transforms.push(
 404                    Transform {
 405                        summary: TransformSummary {
 406                            output: text_summary.clone(),
 407                            input: text_summary,
 408                        },
 409                        output_text: None,
 410                    },
 411                    &(),
 412                );
 413            }
 414        }
 415
 416        new_transforms.push_tree(cursor.suffix(&()), &());
 417        if new_transforms.is_empty() {
 418            let text_summary = buffer.text_summary();
 419            new_transforms.push(
 420                Transform {
 421                    summary: TransformSummary {
 422                        output: text_summary.clone(),
 423                        input: text_summary,
 424                    },
 425                    output_text: None,
 426                },
 427                &(),
 428            );
 429        }
 430
 431        drop(cursor);
 432
 433        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 434        {
 435            let mut old_transforms = transforms.cursor::<usize, FoldOffset>();
 436            let mut new_transforms = new_transforms.cursor::<usize, FoldOffset>();
 437
 438            for mut edit in buffer_edits {
 439                old_transforms.seek(&edit.old_bytes.start, Bias::Left, &());
 440                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 441                    edit.old_bytes.start = *old_transforms.seek_start();
 442                }
 443                let old_start = old_transforms.sum_start().0
 444                    + (edit.old_bytes.start - old_transforms.seek_start());
 445
 446                old_transforms.seek_forward(&edit.old_bytes.end, Bias::Right, &());
 447                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 448                    old_transforms.next(&());
 449                    edit.old_bytes.end = *old_transforms.seek_start();
 450                }
 451                let old_end = old_transforms.sum_start().0
 452                    + (edit.old_bytes.end - old_transforms.seek_start());
 453
 454                new_transforms.seek(&edit.new_bytes.start, Bias::Left, &());
 455                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 456                    edit.new_bytes.start = *new_transforms.seek_start();
 457                }
 458                let new_start = new_transforms.sum_start().0
 459                    + (edit.new_bytes.start - new_transforms.seek_start());
 460
 461                new_transforms.seek_forward(&edit.new_bytes.end, Bias::Right, &());
 462                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 463                    new_transforms.next(&());
 464                    edit.new_bytes.end = *new_transforms.seek_start();
 465                }
 466                let new_end = new_transforms.sum_start().0
 467                    + (edit.new_bytes.end - new_transforms.seek_start());
 468
 469                fold_edits.push(FoldEdit {
 470                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 471                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 472                });
 473            }
 474
 475            consolidate_fold_edits(&mut fold_edits);
 476        }
 477
 478        *transforms = new_transforms;
 479        self.version.fetch_add(1, SeqCst);
 480        fold_edits
 481    }
 482}
 483
 484#[derive(Clone)]
 485pub struct Snapshot {
 486    transforms: SumTree<Transform>,
 487    folds: SumTree<Fold>,
 488    buffer_snapshot: buffer::Snapshot,
 489    pub version: usize,
 490}
 491
 492impl Snapshot {
 493    #[cfg(test)]
 494    pub fn text(&self) -> String {
 495        self.chunks_at(FoldOffset(0)).collect()
 496    }
 497
 498    #[cfg(test)]
 499    pub fn fold_count(&self) -> usize {
 500        self.folds.items(&self.buffer_snapshot).len()
 501    }
 502
 503    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 504        let mut summary = TextSummary::default();
 505
 506        let mut cursor = self.transforms.cursor::<FoldPoint, Point>();
 507        cursor.seek(&range.start, Bias::Right, &());
 508        if let Some(transform) = cursor.item() {
 509            let start_in_transform = range.start.0 - cursor.seek_start().0;
 510            let end_in_transform =
 511                cmp::min(range.end, cursor.seek_end(&())).0 - cursor.seek_start().0;
 512            if let Some(output_text) = transform.output_text {
 513                summary = TextSummary::from(
 514                    &output_text
 515                        [start_in_transform.column as usize..end_in_transform.column as usize],
 516                );
 517            } else {
 518                let buffer_start = *cursor.sum_start() + start_in_transform;
 519                let buffer_end = *cursor.sum_start() + end_in_transform;
 520                summary = self
 521                    .buffer_snapshot
 522                    .text_summary_for_range(buffer_start..buffer_end);
 523            }
 524        }
 525
 526        if range.end > cursor.seek_end(&()) {
 527            cursor.next(&());
 528            summary += &cursor
 529                .summary::<TransformSummary>(&range.end, Bias::Right, &())
 530                .output;
 531            if let Some(transform) = cursor.item() {
 532                let end_in_transform = range.end.0 - cursor.seek_start().0;
 533                if let Some(output_text) = transform.output_text {
 534                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 535                } else {
 536                    let buffer_start = *cursor.sum_start();
 537                    let buffer_end = *cursor.sum_start() + end_in_transform;
 538                    summary += self
 539                        .buffer_snapshot
 540                        .text_summary_for_range(buffer_start..buffer_end);
 541                }
 542            }
 543        }
 544
 545        summary
 546    }
 547
 548    pub fn len(&self) -> FoldOffset {
 549        FoldOffset(self.transforms.summary().output.bytes)
 550    }
 551
 552    #[cfg(test)]
 553    pub fn line_len(&self, row: u32) -> u32 {
 554        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 555        let line_end = if row >= self.max_point().row() {
 556            self.len().0
 557        } else {
 558            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 559        };
 560        (line_end - line_start) as u32
 561    }
 562
 563    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 564        if start_row > self.transforms.summary().output.lines.row {
 565            panic!("invalid display row {}", start_row);
 566        }
 567
 568        let fold_point = FoldPoint::new(start_row, 0);
 569        let mut cursor = self.transforms.cursor();
 570        cursor.seek(&fold_point, Bias::Left, &());
 571        BufferRows { fold_point, cursor }
 572    }
 573
 574    pub fn max_point(&self) -> FoldPoint {
 575        FoldPoint(self.transforms.summary().output.lines)
 576    }
 577
 578    #[cfg(test)]
 579    pub fn longest_row(&self) -> u32 {
 580        self.transforms.summary().output.longest_row
 581    }
 582
 583    pub fn folds_in_range<'a, T>(
 584        &'a self,
 585        range: Range<T>,
 586    ) -> impl Iterator<Item = &'a Range<Anchor>>
 587    where
 588        T: ToOffset,
 589    {
 590        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 591        iter::from_fn(move || {
 592            let item = folds.item().map(|f| &f.0);
 593            folds.next(&self.buffer_snapshot);
 594            item
 595        })
 596    }
 597
 598    pub fn intersects_fold<T>(&self, offset: T) -> bool
 599    where
 600        T: ToOffset,
 601    {
 602        let offset = offset.to_offset(&self.buffer_snapshot);
 603        let mut cursor = self.transforms.cursor::<usize, ()>();
 604        cursor.seek(&offset, Bias::Right, &());
 605        cursor.item().map_or(false, |t| t.output_text.is_some())
 606    }
 607
 608    pub fn is_line_folded(&self, output_row: u32) -> bool {
 609        let mut cursor = self.transforms.cursor::<FoldPoint, ()>();
 610        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 611        while let Some(transform) = cursor.item() {
 612            if transform.output_text.is_some() {
 613                return true;
 614            }
 615            if cursor.seek_end(&()).row() == output_row {
 616                cursor.next(&())
 617            } else {
 618                break;
 619            }
 620        }
 621        false
 622    }
 623
 624    pub fn chunks_at(&self, offset: FoldOffset) -> Chunks {
 625        let mut transform_cursor = self.transforms.cursor::<FoldOffset, usize>();
 626        transform_cursor.seek(&offset, Bias::Right, &());
 627        let overshoot = offset.0 - transform_cursor.seek_start().0;
 628        let buffer_offset = transform_cursor.sum_start() + overshoot;
 629        Chunks {
 630            transform_cursor,
 631            buffer_offset,
 632            buffer_chunks: self
 633                .buffer_snapshot
 634                .text_for_range(buffer_offset..self.buffer_snapshot.len()),
 635        }
 636    }
 637
 638    pub fn highlighted_chunks(&mut self, range: Range<FoldOffset>) -> HighlightedChunks {
 639        let mut transform_cursor = self.transforms.cursor::<FoldOffset, usize>();
 640
 641        transform_cursor.seek(&range.end, Bias::Right, &());
 642        let overshoot = range.end.0 - transform_cursor.seek_start().0;
 643        let buffer_end = transform_cursor.sum_start() + overshoot;
 644
 645        transform_cursor.seek(&range.start, Bias::Right, &());
 646        let overshoot = range.start.0 - transform_cursor.seek_start().0;
 647        let buffer_start = transform_cursor.sum_start() + overshoot;
 648
 649        HighlightedChunks {
 650            transform_cursor,
 651            buffer_offset: buffer_start,
 652            buffer_chunks: self
 653                .buffer_snapshot
 654                .highlighted_text_for_range(buffer_start..buffer_end),
 655            buffer_chunk: None,
 656        }
 657    }
 658
 659    pub fn chars_at<'a>(&'a self, point: FoldPoint) -> impl Iterator<Item = char> + 'a {
 660        let offset = point.to_offset(self);
 661        self.chunks_at(offset).flat_map(str::chars)
 662    }
 663
 664    #[cfg(test)]
 665    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 666        let mut cursor = self.transforms.cursor::<FoldOffset, usize>();
 667        cursor.seek(&offset, Bias::Right, &());
 668        if let Some(transform) = cursor.item() {
 669            let transform_start = cursor.seek_start().0;
 670            if transform.output_text.is_some() {
 671                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 672                    FoldOffset(transform_start)
 673                } else {
 674                    FoldOffset(cursor.seek_end(&()).0)
 675                }
 676            } else {
 677                let overshoot = offset.0 - transform_start;
 678                let buffer_offset = cursor.sum_start() + overshoot;
 679                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 680                FoldOffset(
 681                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 682                        as usize,
 683                )
 684            }
 685        } else {
 686            FoldOffset(self.transforms.summary().output.bytes)
 687        }
 688    }
 689
 690    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 691        let mut cursor = self.transforms.cursor::<FoldPoint, Point>();
 692        cursor.seek(&point, Bias::Right, &());
 693        if let Some(transform) = cursor.item() {
 694            let transform_start = cursor.seek_start().0;
 695            if transform.output_text.is_some() {
 696                if point.0 == transform_start || matches!(bias, Bias::Left) {
 697                    FoldPoint(transform_start)
 698                } else {
 699                    FoldPoint(cursor.seek_end(&()).0)
 700                }
 701            } else {
 702                let overshoot = point.0 - transform_start;
 703                let buffer_position = *cursor.sum_start() + overshoot;
 704                let clipped_buffer_position =
 705                    self.buffer_snapshot.clip_point(buffer_position, bias);
 706                FoldPoint::new(
 707                    point.row(),
 708                    ((point.column() as i32) + clipped_buffer_position.column as i32
 709                        - buffer_position.column as i32) as u32,
 710                )
 711            }
 712        } else {
 713            FoldPoint(self.transforms.summary().output.lines)
 714        }
 715    }
 716}
 717
 718fn intersecting_folds<'a, T>(
 719    buffer: &'a buffer::Snapshot,
 720    folds: &'a SumTree<Fold>,
 721    range: Range<T>,
 722    inclusive: bool,
 723) -> FilterCursor<'a, impl 'a + Fn(&FoldSummary) -> bool, Fold, usize>
 724where
 725    T: ToOffset,
 726{
 727    let start = buffer.anchor_before(range.start.to_offset(buffer));
 728    let end = buffer.anchor_after(range.end.to_offset(buffer));
 729    folds.filter::<_, usize>(
 730        move |summary| {
 731            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 732            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 733
 734            if inclusive {
 735                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 736            } else {
 737                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 738            }
 739        },
 740        buffer,
 741    )
 742}
 743
 744fn consolidate_buffer_edits(edits: &mut Vec<buffer::Edit>) {
 745    edits.sort_unstable_by(|a, b| {
 746        a.old_bytes
 747            .start
 748            .cmp(&b.old_bytes.start)
 749            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 750    });
 751
 752    let mut i = 1;
 753    while i < edits.len() {
 754        let edit = edits[i].clone();
 755        let prev_edit = &mut edits[i - 1];
 756        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 757            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 758            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 759            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 760            edits.remove(i);
 761            continue;
 762        }
 763        i += 1;
 764    }
 765}
 766
 767fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 768    edits.sort_unstable_by(|a, b| {
 769        a.old_bytes
 770            .start
 771            .cmp(&b.old_bytes.start)
 772            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 773    });
 774
 775    let mut i = 1;
 776    while i < edits.len() {
 777        let edit = edits[i].clone();
 778        let prev_edit = &mut edits[i - 1];
 779        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 780            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 781            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 782            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 783            edits.remove(i);
 784            continue;
 785        }
 786        i += 1;
 787    }
 788}
 789
 790#[derive(Clone, Debug, Default, Eq, PartialEq)]
 791struct Transform {
 792    summary: TransformSummary,
 793    output_text: Option<&'static str>,
 794}
 795
 796impl Transform {
 797    fn is_fold(&self) -> bool {
 798        self.output_text.is_some()
 799    }
 800}
 801
 802#[derive(Clone, Debug, Default, Eq, PartialEq)]
 803struct TransformSummary {
 804    output: TextSummary,
 805    input: TextSummary,
 806}
 807
 808impl sum_tree::Item for Transform {
 809    type Summary = TransformSummary;
 810
 811    fn summary(&self) -> Self::Summary {
 812        self.summary.clone()
 813    }
 814}
 815
 816impl sum_tree::Summary for TransformSummary {
 817    type Context = ();
 818
 819    fn add_summary(&mut self, other: &Self, _: &()) {
 820        self.input += &other.input;
 821        self.output += &other.output;
 822    }
 823}
 824
 825impl<'a> sum_tree::Dimension<'a, TransformSummary> for TransformSummary {
 826    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 827        sum_tree::Summary::add_summary(self, summary, &());
 828    }
 829}
 830
 831#[derive(Clone, Debug)]
 832struct Fold(Range<Anchor>);
 833
 834impl Default for Fold {
 835    fn default() -> Self {
 836        Self(Anchor::min()..Anchor::max())
 837    }
 838}
 839
 840impl sum_tree::Item for Fold {
 841    type Summary = FoldSummary;
 842
 843    fn summary(&self) -> Self::Summary {
 844        FoldSummary {
 845            start: self.0.start.clone(),
 846            end: self.0.end.clone(),
 847            min_start: self.0.start.clone(),
 848            max_end: self.0.end.clone(),
 849            count: 1,
 850        }
 851    }
 852}
 853
 854#[derive(Clone, Debug)]
 855struct FoldSummary {
 856    start: Anchor,
 857    end: Anchor,
 858    min_start: Anchor,
 859    max_end: Anchor,
 860    count: usize,
 861}
 862
 863impl Default for FoldSummary {
 864    fn default() -> Self {
 865        Self {
 866            start: Anchor::min(),
 867            end: Anchor::max(),
 868            min_start: Anchor::max(),
 869            max_end: Anchor::min(),
 870            count: 0,
 871        }
 872    }
 873}
 874
 875impl sum_tree::Summary for FoldSummary {
 876    type Context = buffer::Snapshot;
 877
 878    fn add_summary(&mut self, other: &Self, buffer: &buffer::Snapshot) {
 879        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 880            self.min_start = other.min_start.clone();
 881        }
 882        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 883            self.max_end = other.max_end.clone();
 884        }
 885
 886        #[cfg(debug_assertions)]
 887        {
 888            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 889            assert!(start_comparison <= Ordering::Equal);
 890            if start_comparison == Ordering::Equal {
 891                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 892            }
 893        }
 894
 895        self.start = other.start.clone();
 896        self.end = other.end.clone();
 897        self.count += other.count;
 898    }
 899}
 900
 901impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 902    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 903        self.0.start = summary.start.clone();
 904        self.0.end = summary.end.clone();
 905    }
 906}
 907
 908impl<'a> sum_tree::SeekDimension<'a, FoldSummary> for Fold {
 909    fn cmp(&self, other: &Self, buffer: &buffer::Snapshot) -> Ordering {
 910        self.0.cmp(&other.0, buffer).unwrap()
 911    }
 912}
 913
 914impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 915    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 916        *self += summary.count;
 917    }
 918}
 919
 920pub struct BufferRows<'a> {
 921    cursor: Cursor<'a, Transform, FoldPoint, Point>,
 922    fold_point: FoldPoint,
 923}
 924
 925impl<'a> Iterator for BufferRows<'a> {
 926    type Item = u32;
 927
 928    fn next(&mut self) -> Option<Self::Item> {
 929        while self.fold_point > self.cursor.seek_end(&()) {
 930            self.cursor.next(&());
 931            if self.cursor.item().is_none() {
 932                // TODO: Return a bool from next?
 933                break;
 934            }
 935        }
 936
 937        if self.cursor.item().is_some() {
 938            let overshoot = self.fold_point.0 - self.cursor.seek_start().0;
 939            let buffer_point = *self.cursor.sum_start() + overshoot;
 940            *self.fold_point.row_mut() += 1;
 941            Some(buffer_point.row)
 942        } else {
 943            None
 944        }
 945    }
 946}
 947
 948pub struct Chunks<'a> {
 949    transform_cursor: Cursor<'a, Transform, FoldOffset, usize>,
 950    buffer_chunks: buffer::Chunks<'a>,
 951    buffer_offset: usize,
 952}
 953
 954impl<'a> Iterator for Chunks<'a> {
 955    type Item = &'a str;
 956
 957    fn next(&mut self) -> Option<Self::Item> {
 958        let transform = if let Some(item) = self.transform_cursor.item() {
 959            item
 960        } else {
 961            return None;
 962        };
 963
 964        // If we're in a fold, then return the fold's display text and
 965        // advance the transform and buffer cursors to the end of the fold.
 966        if let Some(output_text) = transform.output_text {
 967            self.buffer_offset += transform.summary.input.bytes;
 968            self.buffer_chunks.seek(self.buffer_offset);
 969
 970            while self.buffer_offset >= self.transform_cursor.sum_end(&())
 971                && self.transform_cursor.item().is_some()
 972            {
 973                self.transform_cursor.next(&());
 974            }
 975
 976            return Some(output_text);
 977        }
 978
 979        // Otherwise, take a chunk from the buffer's text.
 980        if let Some(mut chunk) = self.buffer_chunks.peek() {
 981            let offset_in_chunk = self.buffer_offset - self.buffer_chunks.offset();
 982            chunk = &chunk[offset_in_chunk..];
 983
 984            // Truncate the chunk so that it ends at the next fold.
 985            let region_end = self.transform_cursor.sum_end(&()) - self.buffer_offset;
 986            if chunk.len() >= region_end {
 987                chunk = &chunk[0..region_end];
 988                self.transform_cursor.next(&());
 989            } else {
 990                self.buffer_chunks.next();
 991            }
 992
 993            self.buffer_offset += chunk.len();
 994            return Some(chunk);
 995        }
 996
 997        None
 998    }
 999}
1000
1001pub struct HighlightedChunks<'a> {
1002    transform_cursor: Cursor<'a, Transform, FoldOffset, usize>,
1003    buffer_chunks: buffer::HighlightedChunks<'a>,
1004    buffer_chunk: Option<(usize, &'a str, HighlightId)>,
1005    buffer_offset: usize,
1006}
1007
1008impl<'a> Iterator for HighlightedChunks<'a> {
1009    type Item = (&'a str, HighlightId);
1010
1011    fn next(&mut self) -> Option<Self::Item> {
1012        let transform = if let Some(item) = self.transform_cursor.item() {
1013            item
1014        } else {
1015            return None;
1016        };
1017
1018        // If we're in a fold, then return the fold's display text and
1019        // advance the transform and buffer cursors to the end of the fold.
1020        if let Some(output_text) = transform.output_text {
1021            self.buffer_chunk.take();
1022            self.buffer_offset += transform.summary.input.bytes;
1023            self.buffer_chunks.seek(self.buffer_offset);
1024
1025            while self.buffer_offset >= self.transform_cursor.sum_end(&())
1026                && self.transform_cursor.item().is_some()
1027            {
1028                self.transform_cursor.next(&());
1029            }
1030
1031            return Some((output_text, HighlightId::default()));
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
1038                .buffer_chunks
1039                .next()
1040                .map(|(chunk, capture_ix)| (chunk_offset, chunk, capture_ix));
1041        }
1042
1043        // Otherwise, take a chunk from the buffer's text.
1044        if let Some((chunk_offset, mut chunk, capture_ix)) = self.buffer_chunk {
1045            let offset_in_chunk = self.buffer_offset - chunk_offset;
1046            chunk = &chunk[offset_in_chunk..];
1047
1048            // Truncate the chunk so that it ends at the next fold.
1049            let region_end = self.transform_cursor.sum_end(&()) - self.buffer_offset;
1050            if chunk.len() >= region_end {
1051                chunk = &chunk[0..region_end];
1052                self.transform_cursor.next(&());
1053            } else {
1054                self.buffer_chunk.take();
1055            }
1056
1057            self.buffer_offset += chunk.len();
1058            return Some((chunk, capture_ix));
1059        }
1060
1061        None
1062    }
1063}
1064
1065impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1066    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1067        self.0 += &summary.output.lines;
1068    }
1069}
1070
1071#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1072pub struct FoldOffset(pub usize);
1073
1074impl FoldOffset {
1075    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1076        let mut cursor = snapshot.transforms.cursor::<FoldOffset, TransformSummary>();
1077        cursor.seek(self, Bias::Right, &());
1078        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1079            Point::new(0, (self.0 - cursor.seek_start().0) as u32)
1080        } else {
1081            let buffer_offset = cursor.sum_start().input.bytes + self.0 - cursor.seek_start().0;
1082            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1083            buffer_point - cursor.sum_start().input.lines
1084        };
1085        FoldPoint(cursor.sum_start().output.lines + overshoot)
1086    }
1087}
1088
1089impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1090    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1091        self.0 += &summary.output.bytes;
1092    }
1093}
1094
1095impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1096    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1097        *self += &summary.input.lines;
1098    }
1099}
1100
1101impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1102    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1103        *self += &summary.input.bytes;
1104    }
1105}
1106
1107#[derive(Clone, Debug, PartialEq, Eq)]
1108pub struct FoldEdit {
1109    pub old_bytes: Range<FoldOffset>,
1110    pub new_bytes: Range<FoldOffset>,
1111}
1112
1113#[cfg(test)]
1114impl FoldEdit {
1115    pub fn delta(&self) -> isize {
1116        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1117    }
1118
1119    pub fn deleted_bytes(&self) -> usize {
1120        self.old_bytes.end.0 - self.old_bytes.start.0
1121    }
1122
1123    pub fn inserted_bytes(&self) -> usize {
1124        self.new_bytes.end.0 - self.new_bytes.start.0
1125    }
1126}
1127
1128#[cfg(test)]
1129mod tests {
1130    use super::*;
1131    use crate::{editor::ToPoint, test::sample_text, util::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, cx| {
1338                        let start_version = buffer.version.clone();
1339                        let edit_count = rng.gen_range(1..=5);
1340                        buffer.randomly_edit(&mut rng, edit_count, cx);
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}