fold_map.rs

   1use crate::display_map::inlay_map::InlayChunk;
   2
   3use super::{
   4    Highlights,
   5    inlay_map::{InlayBufferRows, InlayChunks, InlayEdit, InlayOffset, InlayPoint, InlaySnapshot},
   6};
   7use gpui::{AnyElement, App, ElementId, HighlightStyle, Pixels, Window};
   8use language::{Edit, HighlightId, Point, TextSummary};
   9use multi_buffer::{
  10    Anchor, AnchorRangeExt, MultiBufferRow, MultiBufferSnapshot, RowInfo, ToOffset,
  11};
  12use project::InlayId;
  13use std::{
  14    any::TypeId,
  15    cmp::{self, Ordering},
  16    fmt, iter,
  17    ops::{Add, AddAssign, Deref, DerefMut, Range, Sub},
  18    sync::Arc,
  19    usize,
  20};
  21use sum_tree::{Bias, Cursor, Dimensions, FilterCursor, SumTree, Summary, TreeMap};
  22use ui::IntoElement as _;
  23use util::post_inc;
  24
  25#[derive(Clone)]
  26pub struct FoldPlaceholder {
  27    /// Creates an element to represent this fold's placeholder.
  28    pub render: Arc<dyn Send + Sync + Fn(FoldId, Range<Anchor>, &mut App) -> AnyElement>,
  29    /// If true, the element is constrained to the shaped width of an ellipsis.
  30    pub constrain_width: bool,
  31    /// If true, merges the fold with an adjacent one.
  32    pub merge_adjacent: bool,
  33    /// Category of the fold. Useful for carefully removing from overlapping folds.
  34    pub type_tag: Option<TypeId>,
  35}
  36
  37impl Default for FoldPlaceholder {
  38    fn default() -> Self {
  39        Self {
  40            render: Arc::new(|_, _, _| gpui::Empty.into_any_element()),
  41            constrain_width: true,
  42            merge_adjacent: true,
  43            type_tag: None,
  44        }
  45    }
  46}
  47
  48impl FoldPlaceholder {
  49    #[cfg(any(test, feature = "test-support"))]
  50    pub fn test() -> Self {
  51        Self {
  52            render: Arc::new(|_id, _range, _cx| gpui::Empty.into_any_element()),
  53            constrain_width: true,
  54            merge_adjacent: true,
  55            type_tag: None,
  56        }
  57    }
  58}
  59
  60impl fmt::Debug for FoldPlaceholder {
  61    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  62        f.debug_struct("FoldPlaceholder")
  63            .field("constrain_width", &self.constrain_width)
  64            .finish()
  65    }
  66}
  67
  68impl Eq for FoldPlaceholder {}
  69
  70impl PartialEq for FoldPlaceholder {
  71    fn eq(&self, other: &Self) -> bool {
  72        Arc::ptr_eq(&self.render, &other.render) && self.constrain_width == other.constrain_width
  73    }
  74}
  75
  76#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  77pub struct FoldPoint(pub Point);
  78
  79impl FoldPoint {
  80    pub fn new(row: u32, column: u32) -> Self {
  81        Self(Point::new(row, column))
  82    }
  83
  84    pub fn row(self) -> u32 {
  85        self.0.row
  86    }
  87
  88    pub fn column(self) -> u32 {
  89        self.0.column
  90    }
  91
  92    pub fn row_mut(&mut self) -> &mut u32 {
  93        &mut self.0.row
  94    }
  95
  96    #[cfg(test)]
  97    pub fn column_mut(&mut self) -> &mut u32 {
  98        &mut self.0.column
  99    }
 100
 101    pub fn to_inlay_point(self, snapshot: &FoldSnapshot) -> InlayPoint {
 102        let (start, _, _) = snapshot
 103            .transforms
 104            .find::<Dimensions<FoldPoint, InlayPoint>, _>((), &self, Bias::Right);
 105        let overshoot = self.0 - start.0.0;
 106        InlayPoint(start.1.0 + overshoot)
 107    }
 108
 109    pub fn to_offset(self, snapshot: &FoldSnapshot) -> FoldOffset {
 110        let (start, _, item) = snapshot
 111            .transforms
 112            .find::<Dimensions<FoldPoint, TransformSummary>, _>((), &self, Bias::Right);
 113        let overshoot = self.0 - start.1.output.lines;
 114        let mut offset = start.1.output.len;
 115        if !overshoot.is_zero() {
 116            let transform = item.expect("display point out of range");
 117            assert!(transform.placeholder.is_none());
 118            let end_inlay_offset = snapshot
 119                .inlay_snapshot
 120                .to_offset(InlayPoint(start.1.input.lines + overshoot));
 121            offset += end_inlay_offset.0 - start.1.input.len;
 122        }
 123        FoldOffset(offset)
 124    }
 125}
 126
 127impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
 128    fn zero(_cx: ()) -> Self {
 129        Default::default()
 130    }
 131
 132    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
 133        self.0 += &summary.output.lines;
 134    }
 135}
 136
 137pub(crate) struct FoldMapWriter<'a>(&'a mut FoldMap);
 138
 139impl FoldMapWriter<'_> {
 140    pub(crate) fn fold<T: ToOffset>(
 141        &mut self,
 142        ranges: impl IntoIterator<Item = (Range<T>, FoldPlaceholder)>,
 143    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 144        let mut edits = Vec::new();
 145        let mut folds = Vec::new();
 146        let snapshot = self.0.snapshot.inlay_snapshot.clone();
 147        for (range, fold_text) in ranges.into_iter() {
 148            let buffer = &snapshot.buffer;
 149            let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 150
 151            // Ignore any empty ranges.
 152            if range.start == range.end {
 153                continue;
 154            }
 155
 156            // For now, ignore any ranges that span an excerpt boundary.
 157            let fold_range =
 158                FoldRange(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 159            if fold_range.0.start.excerpt_id != fold_range.0.end.excerpt_id {
 160                continue;
 161            }
 162
 163            folds.push(Fold {
 164                id: FoldId(post_inc(&mut self.0.next_fold_id.0)),
 165                range: fold_range,
 166                placeholder: fold_text,
 167            });
 168
 169            let inlay_range =
 170                snapshot.to_inlay_offset(range.start)..snapshot.to_inlay_offset(range.end);
 171            edits.push(InlayEdit {
 172                old: inlay_range.clone(),
 173                new: inlay_range,
 174            });
 175        }
 176
 177        let buffer = &snapshot.buffer;
 178        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(&a.range, &b.range, buffer));
 179
 180        self.0.snapshot.folds = {
 181            let mut new_tree = SumTree::new(buffer);
 182            let mut cursor = self.0.snapshot.folds.cursor::<FoldRange>(buffer);
 183            for fold in folds {
 184                self.0.snapshot.fold_metadata_by_id.insert(
 185                    fold.id,
 186                    FoldMetadata {
 187                        range: fold.range.clone(),
 188                        width: None,
 189                    },
 190                );
 191                new_tree.append(cursor.slice(&fold.range, Bias::Right), buffer);
 192                new_tree.push(fold, buffer);
 193            }
 194            new_tree.append(cursor.suffix(), buffer);
 195            new_tree
 196        };
 197
 198        let edits = consolidate_inlay_edits(edits);
 199        let edits = self.0.sync(snapshot.clone(), edits);
 200        (self.0.snapshot.clone(), edits)
 201    }
 202
 203    /// Removes any folds with the given ranges.
 204    pub(crate) fn remove_folds<T: ToOffset>(
 205        &mut self,
 206        ranges: impl IntoIterator<Item = Range<T>>,
 207        type_id: TypeId,
 208    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 209        self.remove_folds_with(
 210            ranges,
 211            |fold| fold.placeholder.type_tag == Some(type_id),
 212            false,
 213        )
 214    }
 215
 216    /// Removes any folds whose ranges intersect the given ranges.
 217    pub(crate) fn unfold_intersecting<T: ToOffset>(
 218        &mut self,
 219        ranges: impl IntoIterator<Item = Range<T>>,
 220        inclusive: bool,
 221    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 222        self.remove_folds_with(ranges, |_| true, inclusive)
 223    }
 224
 225    /// Removes any folds that intersect the given ranges and for which the given predicate
 226    /// returns true.
 227    fn remove_folds_with<T: ToOffset>(
 228        &mut self,
 229        ranges: impl IntoIterator<Item = Range<T>>,
 230        should_unfold: impl Fn(&Fold) -> bool,
 231        inclusive: bool,
 232    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 233        let mut edits = Vec::new();
 234        let mut fold_ixs_to_delete = Vec::new();
 235        let snapshot = self.0.snapshot.inlay_snapshot.clone();
 236        let buffer = &snapshot.buffer;
 237        for range in ranges.into_iter() {
 238            let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 239            let mut folds_cursor =
 240                intersecting_folds(&snapshot, &self.0.snapshot.folds, range.clone(), inclusive);
 241            while let Some(fold) = folds_cursor.item() {
 242                let offset_range =
 243                    fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer);
 244                if should_unfold(fold) {
 245                    if offset_range.end > offset_range.start {
 246                        let inlay_range = snapshot.to_inlay_offset(offset_range.start)
 247                            ..snapshot.to_inlay_offset(offset_range.end);
 248                        edits.push(InlayEdit {
 249                            old: inlay_range.clone(),
 250                            new: inlay_range,
 251                        });
 252                    }
 253                    fold_ixs_to_delete.push(*folds_cursor.start());
 254                    self.0.snapshot.fold_metadata_by_id.remove(&fold.id);
 255                }
 256                folds_cursor.next();
 257            }
 258        }
 259
 260        fold_ixs_to_delete.sort_unstable();
 261        fold_ixs_to_delete.dedup();
 262
 263        self.0.snapshot.folds = {
 264            let mut cursor = self.0.snapshot.folds.cursor::<usize>(buffer);
 265            let mut folds = SumTree::new(buffer);
 266            for fold_ix in fold_ixs_to_delete {
 267                folds.append(cursor.slice(&fold_ix, Bias::Right), buffer);
 268                cursor.next();
 269            }
 270            folds.append(cursor.suffix(), buffer);
 271            folds
 272        };
 273
 274        let edits = consolidate_inlay_edits(edits);
 275        let edits = self.0.sync(snapshot.clone(), edits);
 276        (self.0.snapshot.clone(), edits)
 277    }
 278
 279    pub(crate) fn update_fold_widths(
 280        &mut self,
 281        new_widths: impl IntoIterator<Item = (ChunkRendererId, Pixels)>,
 282    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 283        let mut edits = Vec::new();
 284        let inlay_snapshot = self.0.snapshot.inlay_snapshot.clone();
 285        let buffer = &inlay_snapshot.buffer;
 286
 287        for (id, new_width) in new_widths {
 288            let ChunkRendererId::Fold(id) = id else {
 289                continue;
 290            };
 291            if let Some(metadata) = self.0.snapshot.fold_metadata_by_id.get(&id).cloned()
 292                && Some(new_width) != metadata.width
 293            {
 294                let buffer_start = metadata.range.start.to_offset(buffer);
 295                let buffer_end = metadata.range.end.to_offset(buffer);
 296                let inlay_range = inlay_snapshot.to_inlay_offset(buffer_start)
 297                    ..inlay_snapshot.to_inlay_offset(buffer_end);
 298                edits.push(InlayEdit {
 299                    old: inlay_range.clone(),
 300                    new: inlay_range.clone(),
 301                });
 302
 303                self.0.snapshot.fold_metadata_by_id.insert(
 304                    id,
 305                    FoldMetadata {
 306                        range: metadata.range,
 307                        width: Some(new_width),
 308                    },
 309                );
 310            }
 311        }
 312
 313        let edits = consolidate_inlay_edits(edits);
 314        let edits = self.0.sync(inlay_snapshot, edits);
 315        (self.0.snapshot.clone(), edits)
 316    }
 317}
 318
 319/// Decides where the fold indicators should be; also tracks parts of a source file that are currently folded.
 320///
 321/// See the [`display_map` module documentation](crate::display_map) for more information.
 322pub struct FoldMap {
 323    snapshot: FoldSnapshot,
 324    next_fold_id: FoldId,
 325}
 326
 327impl FoldMap {
 328    pub fn new(inlay_snapshot: InlaySnapshot) -> (Self, FoldSnapshot) {
 329        let this = Self {
 330            snapshot: FoldSnapshot {
 331                folds: SumTree::new(&inlay_snapshot.buffer),
 332                transforms: SumTree::from_item(
 333                    Transform {
 334                        summary: TransformSummary {
 335                            input: inlay_snapshot.text_summary(),
 336                            output: inlay_snapshot.text_summary(),
 337                        },
 338                        placeholder: None,
 339                    },
 340                    (),
 341                ),
 342                inlay_snapshot: inlay_snapshot,
 343                version: 0,
 344                fold_metadata_by_id: TreeMap::default(),
 345            },
 346            next_fold_id: FoldId::default(),
 347        };
 348        let snapshot = this.snapshot.clone();
 349        (this, snapshot)
 350    }
 351
 352    pub fn read(
 353        &mut self,
 354        inlay_snapshot: InlaySnapshot,
 355        edits: Vec<InlayEdit>,
 356    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 357        let edits = self.sync(inlay_snapshot, edits);
 358        self.check_invariants();
 359        (self.snapshot.clone(), edits)
 360    }
 361
 362    pub(crate) fn write(
 363        &mut self,
 364        inlay_snapshot: InlaySnapshot,
 365        edits: Vec<InlayEdit>,
 366    ) -> (FoldMapWriter<'_>, FoldSnapshot, Vec<FoldEdit>) {
 367        let (snapshot, edits) = self.read(inlay_snapshot, edits);
 368        (FoldMapWriter(self), snapshot, edits)
 369    }
 370
 371    fn check_invariants(&self) {
 372        if cfg!(test) {
 373            assert_eq!(
 374                self.snapshot.transforms.summary().input.len,
 375                self.snapshot.inlay_snapshot.len().0,
 376                "transform tree does not match inlay snapshot's length"
 377            );
 378
 379            let mut prev_transform_isomorphic = false;
 380            for transform in self.snapshot.transforms.iter() {
 381                if !transform.is_fold() && prev_transform_isomorphic {
 382                    panic!(
 383                        "found adjacent isomorphic transforms: {:?}",
 384                        self.snapshot.transforms.items(())
 385                    );
 386                }
 387                prev_transform_isomorphic = !transform.is_fold();
 388            }
 389
 390            let mut folds = self.snapshot.folds.iter().peekable();
 391            while let Some(fold) = folds.next() {
 392                if let Some(next_fold) = folds.peek() {
 393                    let comparison = fold.range.cmp(&next_fold.range, self.snapshot.buffer());
 394                    assert!(comparison.is_le());
 395                }
 396            }
 397        }
 398    }
 399
 400    fn sync(
 401        &mut self,
 402        inlay_snapshot: InlaySnapshot,
 403        inlay_edits: Vec<InlayEdit>,
 404    ) -> Vec<FoldEdit> {
 405        if inlay_edits.is_empty() {
 406            if self.snapshot.inlay_snapshot.version != inlay_snapshot.version {
 407                self.snapshot.version += 1;
 408            }
 409            self.snapshot.inlay_snapshot = inlay_snapshot;
 410            Vec::new()
 411        } else {
 412            let mut inlay_edits_iter = inlay_edits.iter().cloned().peekable();
 413
 414            let mut new_transforms = SumTree::<Transform>::default();
 415            let mut cursor = self.snapshot.transforms.cursor::<InlayOffset>(());
 416            cursor.seek(&InlayOffset(0), Bias::Right);
 417
 418            while let Some(mut edit) = inlay_edits_iter.next() {
 419                if let Some(item) = cursor.item()
 420                    && !item.is_fold()
 421                {
 422                    new_transforms.update_last(
 423                        |transform| {
 424                            if !transform.is_fold() {
 425                                transform.summary.add_summary(&item.summary, ());
 426                                cursor.next();
 427                            }
 428                        },
 429                        (),
 430                    );
 431                }
 432                new_transforms.append(cursor.slice(&edit.old.start, Bias::Left), ());
 433                edit.new.start -= edit.old.start - *cursor.start();
 434                edit.old.start = *cursor.start();
 435
 436                cursor.seek(&edit.old.end, Bias::Right);
 437                cursor.next();
 438
 439                let mut delta = edit.new_len().0 as isize - edit.old_len().0 as isize;
 440                loop {
 441                    edit.old.end = *cursor.start();
 442
 443                    if let Some(next_edit) = inlay_edits_iter.peek() {
 444                        if next_edit.old.start > edit.old.end {
 445                            break;
 446                        }
 447
 448                        let next_edit = inlay_edits_iter.next().unwrap();
 449                        delta += next_edit.new_len().0 as isize - next_edit.old_len().0 as isize;
 450
 451                        if next_edit.old.end >= edit.old.end {
 452                            edit.old.end = next_edit.old.end;
 453                            cursor.seek(&edit.old.end, Bias::Right);
 454                            cursor.next();
 455                        }
 456                    } else {
 457                        break;
 458                    }
 459                }
 460
 461                edit.new.end =
 462                    InlayOffset(((edit.new.start + edit.old_len()).0 as isize + delta) as usize);
 463
 464                let anchor = inlay_snapshot
 465                    .buffer
 466                    .anchor_before(inlay_snapshot.to_buffer_offset(edit.new.start));
 467                let mut folds_cursor = self
 468                    .snapshot
 469                    .folds
 470                    .cursor::<FoldRange>(&inlay_snapshot.buffer);
 471                folds_cursor.seek(&FoldRange(anchor..Anchor::max()), Bias::Left);
 472
 473                let mut folds = iter::from_fn({
 474                    let inlay_snapshot = &inlay_snapshot;
 475                    move || {
 476                        let item = folds_cursor.item().map(|fold| {
 477                            let buffer_start = fold.range.start.to_offset(&inlay_snapshot.buffer);
 478                            let buffer_end = fold.range.end.to_offset(&inlay_snapshot.buffer);
 479                            (
 480                                fold.clone(),
 481                                inlay_snapshot.to_inlay_offset(buffer_start)
 482                                    ..inlay_snapshot.to_inlay_offset(buffer_end),
 483                            )
 484                        });
 485                        folds_cursor.next();
 486                        item
 487                    }
 488                })
 489                .peekable();
 490
 491                while folds
 492                    .peek()
 493                    .is_some_and(|(_, fold_range)| fold_range.start < edit.new.end)
 494                {
 495                    let (fold, mut fold_range) = folds.next().unwrap();
 496                    let sum = new_transforms.summary();
 497
 498                    assert!(fold_range.start.0 >= sum.input.len);
 499
 500                    while folds.peek().is_some_and(|(next_fold, next_fold_range)| {
 501                        next_fold_range.start < fold_range.end
 502                            || (next_fold_range.start == fold_range.end
 503                                && fold.placeholder.merge_adjacent
 504                                && next_fold.placeholder.merge_adjacent)
 505                    }) {
 506                        let (_, next_fold_range) = folds.next().unwrap();
 507                        if next_fold_range.end > fold_range.end {
 508                            fold_range.end = next_fold_range.end;
 509                        }
 510                    }
 511
 512                    if fold_range.start.0 > sum.input.len {
 513                        let text_summary = inlay_snapshot
 514                            .text_summary_for_range(InlayOffset(sum.input.len)..fold_range.start);
 515                        push_isomorphic(&mut new_transforms, text_summary);
 516                    }
 517
 518                    if fold_range.end > fold_range.start {
 519                        const ELLIPSIS: &str = "";
 520
 521                        let fold_id = fold.id;
 522                        new_transforms.push(
 523                            Transform {
 524                                summary: TransformSummary {
 525                                    output: TextSummary::from(ELLIPSIS),
 526                                    input: inlay_snapshot
 527                                        .text_summary_for_range(fold_range.start..fold_range.end),
 528                                },
 529                                placeholder: Some(TransformPlaceholder {
 530                                    text: ELLIPSIS,
 531                                    chars: 1,
 532                                    renderer: ChunkRenderer {
 533                                        id: ChunkRendererId::Fold(fold.id),
 534                                        render: Arc::new(move |cx| {
 535                                            (fold.placeholder.render)(
 536                                                fold_id,
 537                                                fold.range.0.clone(),
 538                                                cx.context,
 539                                            )
 540                                        }),
 541                                        constrain_width: fold.placeholder.constrain_width,
 542                                        measured_width: self.snapshot.fold_width(&fold_id),
 543                                    },
 544                                }),
 545                            },
 546                            (),
 547                        );
 548                    }
 549                }
 550
 551                let sum = new_transforms.summary();
 552                if sum.input.len < edit.new.end.0 {
 553                    let text_summary = inlay_snapshot
 554                        .text_summary_for_range(InlayOffset(sum.input.len)..edit.new.end);
 555                    push_isomorphic(&mut new_transforms, text_summary);
 556                }
 557            }
 558
 559            new_transforms.append(cursor.suffix(), ());
 560            if new_transforms.is_empty() {
 561                let text_summary = inlay_snapshot.text_summary();
 562                push_isomorphic(&mut new_transforms, text_summary);
 563            }
 564
 565            drop(cursor);
 566
 567            let mut fold_edits = Vec::with_capacity(inlay_edits.len());
 568            {
 569                let mut old_transforms = self
 570                    .snapshot
 571                    .transforms
 572                    .cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 573                let mut new_transforms =
 574                    new_transforms.cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 575
 576                for mut edit in inlay_edits {
 577                    old_transforms.seek(&edit.old.start, Bias::Left);
 578                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 579                        edit.old.start = old_transforms.start().0;
 580                    }
 581                    let old_start =
 582                        old_transforms.start().1.0 + (edit.old.start - old_transforms.start().0).0;
 583
 584                    old_transforms.seek_forward(&edit.old.end, Bias::Right);
 585                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 586                        old_transforms.next();
 587                        edit.old.end = old_transforms.start().0;
 588                    }
 589                    let old_end =
 590                        old_transforms.start().1.0 + (edit.old.end - old_transforms.start().0).0;
 591
 592                    new_transforms.seek(&edit.new.start, Bias::Left);
 593                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 594                        edit.new.start = new_transforms.start().0;
 595                    }
 596                    let new_start =
 597                        new_transforms.start().1.0 + (edit.new.start - new_transforms.start().0).0;
 598
 599                    new_transforms.seek_forward(&edit.new.end, Bias::Right);
 600                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 601                        new_transforms.next();
 602                        edit.new.end = new_transforms.start().0;
 603                    }
 604                    let new_end =
 605                        new_transforms.start().1.0 + (edit.new.end - new_transforms.start().0).0;
 606
 607                    fold_edits.push(FoldEdit {
 608                        old: FoldOffset(old_start)..FoldOffset(old_end),
 609                        new: FoldOffset(new_start)..FoldOffset(new_end),
 610                    });
 611                }
 612
 613                fold_edits = consolidate_fold_edits(fold_edits);
 614            }
 615
 616            self.snapshot.transforms = new_transforms;
 617            self.snapshot.inlay_snapshot = inlay_snapshot;
 618            self.snapshot.version += 1;
 619            fold_edits
 620        }
 621    }
 622}
 623
 624#[derive(Clone)]
 625pub struct FoldSnapshot {
 626    pub inlay_snapshot: InlaySnapshot,
 627    transforms: SumTree<Transform>,
 628    folds: SumTree<Fold>,
 629    fold_metadata_by_id: TreeMap<FoldId, FoldMetadata>,
 630    pub version: usize,
 631}
 632
 633impl Deref for FoldSnapshot {
 634    type Target = InlaySnapshot;
 635
 636    fn deref(&self) -> &Self::Target {
 637        &self.inlay_snapshot
 638    }
 639}
 640
 641impl FoldSnapshot {
 642    pub fn buffer(&self) -> &MultiBufferSnapshot {
 643        &self.inlay_snapshot.buffer
 644    }
 645
 646    fn fold_width(&self, fold_id: &FoldId) -> Option<Pixels> {
 647        self.fold_metadata_by_id.get(fold_id)?.width
 648    }
 649
 650    #[cfg(test)]
 651    pub fn text(&self) -> String {
 652        self.chunks(FoldOffset(0)..self.len(), false, Highlights::default())
 653            .map(|c| c.text)
 654            .collect()
 655    }
 656
 657    #[cfg(test)]
 658    pub fn fold_count(&self) -> usize {
 659        self.folds.items(&self.inlay_snapshot.buffer).len()
 660    }
 661
 662    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 663        let mut summary = TextSummary::default();
 664
 665        let mut cursor = self
 666            .transforms
 667            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 668        cursor.seek(&range.start, Bias::Right);
 669        if let Some(transform) = cursor.item() {
 670            let start_in_transform = range.start.0 - cursor.start().0.0;
 671            let end_in_transform = cmp::min(range.end, cursor.end().0).0 - cursor.start().0.0;
 672            if let Some(placeholder) = transform.placeholder.as_ref() {
 673                summary = TextSummary::from(
 674                    &placeholder.text
 675                        [start_in_transform.column as usize..end_in_transform.column as usize],
 676                );
 677            } else {
 678                let inlay_start = self
 679                    .inlay_snapshot
 680                    .to_offset(InlayPoint(cursor.start().1.0 + start_in_transform));
 681                let inlay_end = self
 682                    .inlay_snapshot
 683                    .to_offset(InlayPoint(cursor.start().1.0 + end_in_transform));
 684                summary = self
 685                    .inlay_snapshot
 686                    .text_summary_for_range(inlay_start..inlay_end);
 687            }
 688        }
 689
 690        if range.end > cursor.end().0 {
 691            cursor.next();
 692            summary += &cursor
 693                .summary::<_, TransformSummary>(&range.end, Bias::Right)
 694                .output;
 695            if let Some(transform) = cursor.item() {
 696                let end_in_transform = range.end.0 - cursor.start().0.0;
 697                if let Some(placeholder) = transform.placeholder.as_ref() {
 698                    summary +=
 699                        TextSummary::from(&placeholder.text[..end_in_transform.column as usize]);
 700                } else {
 701                    let inlay_start = self.inlay_snapshot.to_offset(cursor.start().1);
 702                    let inlay_end = self
 703                        .inlay_snapshot
 704                        .to_offset(InlayPoint(cursor.start().1.0 + end_in_transform));
 705                    summary += self
 706                        .inlay_snapshot
 707                        .text_summary_for_range(inlay_start..inlay_end);
 708                }
 709            }
 710        }
 711
 712        summary
 713    }
 714
 715    pub fn to_fold_point(&self, point: InlayPoint, bias: Bias) -> FoldPoint {
 716        let (start, end, item) = self
 717            .transforms
 718            .find::<Dimensions<InlayPoint, FoldPoint>, _>((), &point, Bias::Right);
 719        if item.is_some_and(|t| t.is_fold()) {
 720            if bias == Bias::Left || point == start.0 {
 721                start.1
 722            } else {
 723                end.1
 724            }
 725        } else {
 726            let overshoot = point.0 - start.0.0;
 727            FoldPoint(cmp::min(start.1.0 + overshoot, end.1.0))
 728        }
 729    }
 730
 731    pub fn len(&self) -> FoldOffset {
 732        FoldOffset(self.transforms.summary().output.len)
 733    }
 734
 735    pub fn line_len(&self, row: u32) -> u32 {
 736        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 737        let line_end = if row >= self.max_point().row() {
 738            self.len().0
 739        } else {
 740            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 741        };
 742        (line_end - line_start) as u32
 743    }
 744
 745    pub fn row_infos(&self, start_row: u32) -> FoldRows<'_> {
 746        if start_row > self.transforms.summary().output.lines.row {
 747            panic!("invalid display row {}", start_row);
 748        }
 749
 750        let fold_point = FoldPoint::new(start_row, 0);
 751        let mut cursor = self
 752            .transforms
 753            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 754        cursor.seek(&fold_point, Bias::Left);
 755
 756        let overshoot = fold_point.0 - cursor.start().0.0;
 757        let inlay_point = InlayPoint(cursor.start().1.0 + overshoot);
 758        let input_rows = self.inlay_snapshot.row_infos(inlay_point.row());
 759
 760        FoldRows {
 761            fold_point,
 762            input_rows,
 763            cursor,
 764        }
 765    }
 766
 767    pub fn max_point(&self) -> FoldPoint {
 768        FoldPoint(self.transforms.summary().output.lines)
 769    }
 770
 771    #[cfg(test)]
 772    pub fn longest_row(&self) -> u32 {
 773        self.transforms.summary().output.longest_row
 774    }
 775
 776    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Fold>
 777    where
 778        T: ToOffset,
 779    {
 780        let buffer = &self.inlay_snapshot.buffer;
 781        let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 782        let mut folds = intersecting_folds(&self.inlay_snapshot, &self.folds, range, false);
 783        iter::from_fn(move || {
 784            let item = folds.item();
 785            folds.next();
 786            item
 787        })
 788    }
 789
 790    pub fn intersects_fold<T>(&self, offset: T) -> bool
 791    where
 792        T: ToOffset,
 793    {
 794        let buffer_offset = offset.to_offset(&self.inlay_snapshot.buffer);
 795        let inlay_offset = self.inlay_snapshot.to_inlay_offset(buffer_offset);
 796        let (_, _, item) = self
 797            .transforms
 798            .find::<InlayOffset, _>((), &inlay_offset, Bias::Right);
 799        item.is_some_and(|t| t.placeholder.is_some())
 800    }
 801
 802    pub fn is_line_folded(&self, buffer_row: MultiBufferRow) -> bool {
 803        let mut inlay_point = self
 804            .inlay_snapshot
 805            .to_inlay_point(Point::new(buffer_row.0, 0));
 806        let mut cursor = self.transforms.cursor::<InlayPoint>(());
 807        cursor.seek(&inlay_point, Bias::Right);
 808        loop {
 809            match cursor.item() {
 810                Some(transform) => {
 811                    let buffer_point = self.inlay_snapshot.to_buffer_point(inlay_point);
 812                    if buffer_point.row != buffer_row.0 {
 813                        return false;
 814                    } else if transform.placeholder.is_some() {
 815                        return true;
 816                    }
 817                }
 818                None => return false,
 819            }
 820
 821            if cursor.end().row() == inlay_point.row() {
 822                cursor.next();
 823            } else {
 824                inlay_point.0 += Point::new(1, 0);
 825                cursor.seek(&inlay_point, Bias::Right);
 826            }
 827        }
 828    }
 829
 830    pub(crate) fn chunks<'a>(
 831        &'a self,
 832        range: Range<FoldOffset>,
 833        language_aware: bool,
 834        highlights: Highlights<'a>,
 835    ) -> FoldChunks<'a> {
 836        let mut transform_cursor = self
 837            .transforms
 838            .cursor::<Dimensions<FoldOffset, InlayOffset>>(());
 839        transform_cursor.seek(&range.start, Bias::Right);
 840
 841        let inlay_start = {
 842            let overshoot = range.start.0 - transform_cursor.start().0.0;
 843            transform_cursor.start().1 + InlayOffset(overshoot)
 844        };
 845
 846        let transform_end = transform_cursor.end();
 847
 848        let inlay_end = if transform_cursor
 849            .item()
 850            .is_none_or(|transform| transform.is_fold())
 851        {
 852            inlay_start
 853        } else if range.end < transform_end.0 {
 854            let overshoot = range.end.0 - transform_cursor.start().0.0;
 855            transform_cursor.start().1 + InlayOffset(overshoot)
 856        } else {
 857            transform_end.1
 858        };
 859
 860        FoldChunks {
 861            transform_cursor,
 862            inlay_chunks: self.inlay_snapshot.chunks(
 863                inlay_start..inlay_end,
 864                language_aware,
 865                highlights,
 866            ),
 867            inlay_chunk: None,
 868            inlay_offset: inlay_start,
 869            output_offset: range.start,
 870            max_output_offset: range.end,
 871        }
 872    }
 873
 874    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 875        self.chunks(
 876            start.to_offset(self)..self.len(),
 877            false,
 878            Highlights::default(),
 879        )
 880        .flat_map(|chunk| chunk.text.chars())
 881    }
 882
 883    pub fn chunks_at(&self, start: FoldPoint) -> FoldChunks<'_> {
 884        self.chunks(
 885            start.to_offset(self)..self.len(),
 886            false,
 887            Highlights::default(),
 888        )
 889    }
 890
 891    #[cfg(test)]
 892    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 893        if offset > self.len() {
 894            self.len()
 895        } else {
 896            self.clip_point(offset.to_point(self), bias).to_offset(self)
 897        }
 898    }
 899
 900    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 901        let (start, end, item) = self
 902            .transforms
 903            .find::<Dimensions<FoldPoint, InlayPoint>, _>((), &point, Bias::Right);
 904        if let Some(transform) = item {
 905            let transform_start = start.0.0;
 906            if transform.placeholder.is_some() {
 907                if point.0 == transform_start || matches!(bias, Bias::Left) {
 908                    FoldPoint(transform_start)
 909                } else {
 910                    FoldPoint(end.0.0)
 911                }
 912            } else {
 913                let overshoot = InlayPoint(point.0 - transform_start);
 914                let inlay_point = start.1 + overshoot;
 915                let clipped_inlay_point = self.inlay_snapshot.clip_point(inlay_point, bias);
 916                FoldPoint(start.0.0 + (clipped_inlay_point - start.1).0)
 917            }
 918        } else {
 919            FoldPoint(self.transforms.summary().output.lines)
 920        }
 921    }
 922}
 923
 924fn push_isomorphic(transforms: &mut SumTree<Transform>, summary: TextSummary) {
 925    let mut did_merge = false;
 926    transforms.update_last(
 927        |last| {
 928            if !last.is_fold() {
 929                last.summary.input += summary;
 930                last.summary.output += summary;
 931                did_merge = true;
 932            }
 933        },
 934        (),
 935    );
 936    if !did_merge {
 937        transforms.push(
 938            Transform {
 939                summary: TransformSummary {
 940                    input: summary,
 941                    output: summary,
 942                },
 943                placeholder: None,
 944            },
 945            (),
 946        )
 947    }
 948}
 949
 950fn intersecting_folds<'a>(
 951    inlay_snapshot: &'a InlaySnapshot,
 952    folds: &'a SumTree<Fold>,
 953    range: Range<usize>,
 954    inclusive: bool,
 955) -> FilterCursor<'a, 'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize> {
 956    let buffer = &inlay_snapshot.buffer;
 957    let start = buffer.anchor_before(range.start.to_offset(buffer));
 958    let end = buffer.anchor_after(range.end.to_offset(buffer));
 959    let mut cursor = folds.filter::<_, usize>(buffer, move |summary| {
 960        let start_cmp = start.cmp(&summary.max_end, buffer);
 961        let end_cmp = end.cmp(&summary.min_start, buffer);
 962
 963        if inclusive {
 964            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 965        } else {
 966            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 967        }
 968    });
 969    cursor.next();
 970    cursor
 971}
 972
 973fn consolidate_inlay_edits(mut edits: Vec<InlayEdit>) -> Vec<InlayEdit> {
 974    edits.sort_unstable_by(|a, b| {
 975        a.old
 976            .start
 977            .cmp(&b.old.start)
 978            .then_with(|| b.old.end.cmp(&a.old.end))
 979    });
 980
 981    let _old_alloc_ptr = edits.as_ptr();
 982    let mut inlay_edits = edits.into_iter();
 983
 984    if let Some(mut first_edit) = inlay_edits.next() {
 985        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
 986        #[allow(clippy::filter_map_identity)]
 987        let mut v: Vec<_> = inlay_edits
 988            .scan(&mut first_edit, |prev_edit, edit| {
 989                if prev_edit.old.end >= edit.old.start {
 990                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
 991                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
 992                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
 993                    Some(None) // Skip this edit, it's merged
 994                } else {
 995                    let prev = std::mem::replace(*prev_edit, edit);
 996                    Some(Some(prev)) // Yield the previous edit
 997                }
 998            })
 999            .filter_map(|x| x)
1000            .collect();
1001        v.push(first_edit.clone());
1002        debug_assert_eq!(_old_alloc_ptr, v.as_ptr(), "Inlay edits were reallocated");
1003        v
1004    } else {
1005        vec![]
1006    }
1007}
1008
1009fn consolidate_fold_edits(mut edits: Vec<FoldEdit>) -> Vec<FoldEdit> {
1010    edits.sort_unstable_by(|a, b| {
1011        a.old
1012            .start
1013            .cmp(&b.old.start)
1014            .then_with(|| b.old.end.cmp(&a.old.end))
1015    });
1016    let _old_alloc_ptr = edits.as_ptr();
1017    let mut fold_edits = edits.into_iter();
1018
1019    if let Some(mut first_edit) = fold_edits.next() {
1020        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
1021        #[allow(clippy::filter_map_identity)]
1022        let mut v: Vec<_> = fold_edits
1023            .scan(&mut first_edit, |prev_edit, edit| {
1024                if prev_edit.old.end >= edit.old.start {
1025                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
1026                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
1027                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
1028                    Some(None) // Skip this edit, it's merged
1029                } else {
1030                    let prev = std::mem::replace(*prev_edit, edit);
1031                    Some(Some(prev)) // Yield the previous edit
1032                }
1033            })
1034            .filter_map(|x| x)
1035            .collect();
1036        v.push(first_edit.clone());
1037        v
1038    } else {
1039        vec![]
1040    }
1041}
1042
1043#[derive(Clone, Debug, Default)]
1044struct Transform {
1045    summary: TransformSummary,
1046    placeholder: Option<TransformPlaceholder>,
1047}
1048
1049#[derive(Clone, Debug)]
1050struct TransformPlaceholder {
1051    text: &'static str,
1052    chars: u128,
1053    renderer: ChunkRenderer,
1054}
1055
1056impl Transform {
1057    fn is_fold(&self) -> bool {
1058        self.placeholder.is_some()
1059    }
1060}
1061
1062#[derive(Clone, Debug, Default, Eq, PartialEq)]
1063struct TransformSummary {
1064    output: TextSummary,
1065    input: TextSummary,
1066}
1067
1068impl sum_tree::Item for Transform {
1069    type Summary = TransformSummary;
1070
1071    fn summary(&self, _cx: ()) -> Self::Summary {
1072        self.summary.clone()
1073    }
1074}
1075
1076impl sum_tree::ContextLessSummary for TransformSummary {
1077    fn zero() -> Self {
1078        Default::default()
1079    }
1080
1081    fn add_summary(&mut self, other: &Self) {
1082        self.input += &other.input;
1083        self.output += &other.output;
1084    }
1085}
1086
1087#[derive(Copy, Clone, Eq, PartialEq, Debug, Default, Ord, PartialOrd, Hash)]
1088pub struct FoldId(pub(super) usize);
1089
1090impl From<FoldId> for ElementId {
1091    fn from(val: FoldId) -> Self {
1092        val.0.into()
1093    }
1094}
1095
1096#[derive(Clone, Debug, Eq, PartialEq)]
1097pub struct Fold {
1098    pub id: FoldId,
1099    pub range: FoldRange,
1100    pub placeholder: FoldPlaceholder,
1101}
1102
1103#[derive(Clone, Debug, Eq, PartialEq)]
1104pub struct FoldRange(Range<Anchor>);
1105
1106impl Deref for FoldRange {
1107    type Target = Range<Anchor>;
1108
1109    fn deref(&self) -> &Self::Target {
1110        &self.0
1111    }
1112}
1113
1114impl DerefMut for FoldRange {
1115    fn deref_mut(&mut self) -> &mut Self::Target {
1116        &mut self.0
1117    }
1118}
1119
1120impl Default for FoldRange {
1121    fn default() -> Self {
1122        Self(Anchor::min()..Anchor::max())
1123    }
1124}
1125
1126#[derive(Clone, Debug)]
1127struct FoldMetadata {
1128    range: FoldRange,
1129    width: Option<Pixels>,
1130}
1131
1132impl sum_tree::Item for Fold {
1133    type Summary = FoldSummary;
1134
1135    fn summary(&self, _cx: &MultiBufferSnapshot) -> Self::Summary {
1136        FoldSummary {
1137            start: self.range.start,
1138            end: self.range.end,
1139            min_start: self.range.start,
1140            max_end: self.range.end,
1141            count: 1,
1142        }
1143    }
1144}
1145
1146#[derive(Clone, Debug)]
1147pub struct FoldSummary {
1148    start: Anchor,
1149    end: Anchor,
1150    min_start: Anchor,
1151    max_end: Anchor,
1152    count: usize,
1153}
1154
1155impl Default for FoldSummary {
1156    fn default() -> Self {
1157        Self {
1158            start: Anchor::min(),
1159            end: Anchor::max(),
1160            min_start: Anchor::max(),
1161            max_end: Anchor::min(),
1162            count: 0,
1163        }
1164    }
1165}
1166
1167impl sum_tree::Summary for FoldSummary {
1168    type Context<'a> = &'a MultiBufferSnapshot;
1169
1170    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1171        Default::default()
1172    }
1173
1174    fn add_summary(&mut self, other: &Self, buffer: Self::Context<'_>) {
1175        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
1176            self.min_start = other.min_start;
1177        }
1178        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
1179            self.max_end = other.max_end;
1180        }
1181
1182        #[cfg(debug_assertions)]
1183        {
1184            let start_comparison = self.start.cmp(&other.start, buffer);
1185            assert!(start_comparison <= Ordering::Equal);
1186            if start_comparison == Ordering::Equal {
1187                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
1188            }
1189        }
1190
1191        self.start = other.start;
1192        self.end = other.end;
1193        self.count += other.count;
1194    }
1195}
1196
1197impl<'a> sum_tree::Dimension<'a, FoldSummary> for FoldRange {
1198    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1199        Default::default()
1200    }
1201
1202    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1203        self.0.start = summary.start;
1204        self.0.end = summary.end;
1205    }
1206}
1207
1208impl sum_tree::SeekTarget<'_, FoldSummary, FoldRange> for FoldRange {
1209    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
1210        AnchorRangeExt::cmp(&self.0, &other.0, buffer)
1211    }
1212}
1213
1214impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
1215    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1216        Default::default()
1217    }
1218
1219    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1220        *self += summary.count;
1221    }
1222}
1223
1224#[derive(Clone)]
1225pub struct FoldRows<'a> {
1226    cursor: Cursor<'a, 'static, Transform, Dimensions<FoldPoint, InlayPoint>>,
1227    input_rows: InlayBufferRows<'a>,
1228    fold_point: FoldPoint,
1229}
1230
1231impl FoldRows<'_> {
1232    pub(crate) fn seek(&mut self, row: u32) {
1233        let fold_point = FoldPoint::new(row, 0);
1234        self.cursor.seek(&fold_point, Bias::Left);
1235        let overshoot = fold_point.0 - self.cursor.start().0.0;
1236        let inlay_point = InlayPoint(self.cursor.start().1.0 + overshoot);
1237        self.input_rows.seek(inlay_point.row());
1238        self.fold_point = fold_point;
1239    }
1240}
1241
1242impl Iterator for FoldRows<'_> {
1243    type Item = RowInfo;
1244
1245    fn next(&mut self) -> Option<Self::Item> {
1246        let mut traversed_fold = false;
1247        while self.fold_point > self.cursor.end().0 {
1248            self.cursor.next();
1249            traversed_fold = true;
1250            if self.cursor.item().is_none() {
1251                break;
1252            }
1253        }
1254
1255        if self.cursor.item().is_some() {
1256            if traversed_fold {
1257                self.input_rows.seek(self.cursor.start().1.0.row);
1258                self.input_rows.next();
1259            }
1260            *self.fold_point.row_mut() += 1;
1261            self.input_rows.next()
1262        } else {
1263            None
1264        }
1265    }
1266}
1267
1268/// A chunk of a buffer's text, along with its syntax highlight and
1269/// diagnostic status.
1270#[derive(Clone, Debug, Default)]
1271pub struct Chunk<'a> {
1272    /// The text of the chunk.
1273    pub text: &'a str,
1274    /// The syntax highlighting style of the chunk.
1275    pub syntax_highlight_id: Option<HighlightId>,
1276    /// The highlight style that has been applied to this chunk in
1277    /// the editor.
1278    pub highlight_style: Option<HighlightStyle>,
1279    /// The severity of diagnostic associated with this chunk, if any.
1280    pub diagnostic_severity: Option<lsp::DiagnosticSeverity>,
1281    /// Whether this chunk of text is marked as unnecessary.
1282    pub is_unnecessary: bool,
1283    /// Whether this chunk of text should be underlined.
1284    pub underline: bool,
1285    /// Whether this chunk of text was originally a tab character.
1286    pub is_tab: bool,
1287    /// Whether this chunk of text was originally a tab character.
1288    pub is_inlay: bool,
1289    /// An optional recipe for how the chunk should be presented.
1290    pub renderer: Option<ChunkRenderer>,
1291    /// Bitmap of tab character locations in chunk
1292    pub tabs: u128,
1293    /// Bitmap of character locations in chunk
1294    pub chars: u128,
1295}
1296
1297#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
1298pub enum ChunkRendererId {
1299    Fold(FoldId),
1300    Inlay(InlayId),
1301}
1302
1303/// A recipe for how the chunk should be presented.
1304#[derive(Clone)]
1305pub struct ChunkRenderer {
1306    /// The id of the renderer associated with this chunk.
1307    pub id: ChunkRendererId,
1308    /// Creates a custom element to represent this chunk.
1309    pub render: Arc<dyn Send + Sync + Fn(&mut ChunkRendererContext) -> AnyElement>,
1310    /// If true, the element is constrained to the shaped width of the text.
1311    pub constrain_width: bool,
1312    /// The width of the element, as measured during the last layout pass.
1313    ///
1314    /// This is None if the element has not been laid out yet.
1315    pub measured_width: Option<Pixels>,
1316}
1317
1318pub struct ChunkRendererContext<'a, 'b> {
1319    pub window: &'a mut Window,
1320    pub context: &'b mut App,
1321    pub max_width: Pixels,
1322}
1323
1324impl fmt::Debug for ChunkRenderer {
1325    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1326        f.debug_struct("ChunkRenderer")
1327            .field("constrain_width", &self.constrain_width)
1328            .finish()
1329    }
1330}
1331
1332impl Deref for ChunkRendererContext<'_, '_> {
1333    type Target = App;
1334
1335    fn deref(&self) -> &Self::Target {
1336        self.context
1337    }
1338}
1339
1340impl DerefMut for ChunkRendererContext<'_, '_> {
1341    fn deref_mut(&mut self) -> &mut Self::Target {
1342        self.context
1343    }
1344}
1345
1346pub struct FoldChunks<'a> {
1347    transform_cursor: Cursor<'a, 'static, Transform, Dimensions<FoldOffset, InlayOffset>>,
1348    inlay_chunks: InlayChunks<'a>,
1349    inlay_chunk: Option<(InlayOffset, InlayChunk<'a>)>,
1350    inlay_offset: InlayOffset,
1351    output_offset: FoldOffset,
1352    max_output_offset: FoldOffset,
1353}
1354
1355impl FoldChunks<'_> {
1356    pub(crate) fn seek(&mut self, range: Range<FoldOffset>) {
1357        self.transform_cursor.seek(&range.start, Bias::Right);
1358
1359        let inlay_start = {
1360            let overshoot = range.start.0 - self.transform_cursor.start().0.0;
1361            self.transform_cursor.start().1 + InlayOffset(overshoot)
1362        };
1363
1364        let transform_end = self.transform_cursor.end();
1365
1366        let inlay_end = if self
1367            .transform_cursor
1368            .item()
1369            .is_none_or(|transform| transform.is_fold())
1370        {
1371            inlay_start
1372        } else if range.end < transform_end.0 {
1373            let overshoot = range.end.0 - self.transform_cursor.start().0.0;
1374            self.transform_cursor.start().1 + InlayOffset(overshoot)
1375        } else {
1376            transform_end.1
1377        };
1378
1379        self.inlay_chunks.seek(inlay_start..inlay_end);
1380        self.inlay_chunk = None;
1381        self.inlay_offset = inlay_start;
1382        self.output_offset = range.start;
1383        self.max_output_offset = range.end;
1384    }
1385}
1386
1387impl<'a> Iterator for FoldChunks<'a> {
1388    type Item = Chunk<'a>;
1389
1390    fn next(&mut self) -> Option<Self::Item> {
1391        if self.output_offset >= self.max_output_offset {
1392            return None;
1393        }
1394
1395        let transform = self.transform_cursor.item()?;
1396
1397        // If we're in a fold, then return the fold's display text and
1398        // advance the transform and buffer cursors to the end of the fold.
1399        if let Some(placeholder) = transform.placeholder.as_ref() {
1400            self.inlay_chunk.take();
1401            self.inlay_offset += InlayOffset(transform.summary.input.len);
1402
1403            while self.inlay_offset >= self.transform_cursor.end().1
1404                && self.transform_cursor.item().is_some()
1405            {
1406                self.transform_cursor.next();
1407            }
1408
1409            self.output_offset.0 += placeholder.text.len();
1410            return Some(Chunk {
1411                text: placeholder.text,
1412                chars: placeholder.chars,
1413                renderer: Some(placeholder.renderer.clone()),
1414                ..Default::default()
1415            });
1416        }
1417
1418        // When we reach a non-fold region, seek the underlying text
1419        // chunk iterator to the next unfolded range.
1420        if self.inlay_offset == self.transform_cursor.start().1
1421            && self.inlay_chunks.offset() != self.inlay_offset
1422        {
1423            let transform_start = self.transform_cursor.start();
1424            let transform_end = self.transform_cursor.end();
1425            let inlay_end = if self.max_output_offset < transform_end.0 {
1426                let overshoot = self.max_output_offset.0 - transform_start.0.0;
1427                transform_start.1 + InlayOffset(overshoot)
1428            } else {
1429                transform_end.1
1430            };
1431
1432            self.inlay_chunks.seek(self.inlay_offset..inlay_end);
1433        }
1434
1435        // Retrieve a chunk from the current location in the buffer.
1436        if self.inlay_chunk.is_none() {
1437            let chunk_offset = self.inlay_chunks.offset();
1438            self.inlay_chunk = self.inlay_chunks.next().map(|chunk| (chunk_offset, chunk));
1439        }
1440
1441        // Otherwise, take a chunk from the buffer's text.
1442        if let Some((buffer_chunk_start, mut inlay_chunk)) = self.inlay_chunk.clone() {
1443            let chunk = &mut inlay_chunk.chunk;
1444            let buffer_chunk_end = buffer_chunk_start + InlayOffset(chunk.text.len());
1445            let transform_end = self.transform_cursor.end().1;
1446            let chunk_end = buffer_chunk_end.min(transform_end);
1447
1448            let bit_start = (self.inlay_offset - buffer_chunk_start).0;
1449            let bit_end = (chunk_end - buffer_chunk_start).0;
1450            chunk.text = &chunk.text[bit_start..bit_end];
1451
1452            let bit_end = (chunk_end - buffer_chunk_start).0;
1453            let mask = 1u128.unbounded_shl(bit_end as u32).wrapping_sub(1);
1454
1455            chunk.tabs = (chunk.tabs >> bit_start) & mask;
1456            chunk.chars = (chunk.chars >> bit_start) & mask;
1457
1458            if chunk_end == transform_end {
1459                self.transform_cursor.next();
1460            } else if chunk_end == buffer_chunk_end {
1461                self.inlay_chunk.take();
1462            }
1463
1464            self.inlay_offset = chunk_end;
1465            self.output_offset.0 += chunk.text.len();
1466            return Some(Chunk {
1467                text: chunk.text,
1468                tabs: chunk.tabs,
1469                chars: chunk.chars,
1470                syntax_highlight_id: chunk.syntax_highlight_id,
1471                highlight_style: chunk.highlight_style,
1472                diagnostic_severity: chunk.diagnostic_severity,
1473                is_unnecessary: chunk.is_unnecessary,
1474                is_tab: chunk.is_tab,
1475                is_inlay: chunk.is_inlay,
1476                underline: chunk.underline,
1477                renderer: inlay_chunk.renderer,
1478            });
1479        }
1480
1481        None
1482    }
1483}
1484
1485#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1486pub struct FoldOffset(pub usize);
1487
1488impl FoldOffset {
1489    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1490        let (start, _, item) = snapshot
1491            .transforms
1492            .find::<Dimensions<FoldOffset, TransformSummary>, _>((), &self, Bias::Right);
1493        let overshoot = if item.is_none_or(|t| t.is_fold()) {
1494            Point::new(0, (self.0 - start.0.0) as u32)
1495        } else {
1496            let inlay_offset = start.1.input.len + self.0 - start.0.0;
1497            let inlay_point = snapshot.inlay_snapshot.to_point(InlayOffset(inlay_offset));
1498            inlay_point.0 - start.1.input.lines
1499        };
1500        FoldPoint(start.1.output.lines + overshoot)
1501    }
1502
1503    #[cfg(test)]
1504    pub fn to_inlay_offset(self, snapshot: &FoldSnapshot) -> InlayOffset {
1505        let (start, _, _) = snapshot
1506            .transforms
1507            .find::<Dimensions<FoldOffset, InlayOffset>, _>((), &self, Bias::Right);
1508        let overshoot = self.0 - start.0.0;
1509        InlayOffset(start.1.0 + overshoot)
1510    }
1511}
1512
1513impl Add for FoldOffset {
1514    type Output = Self;
1515
1516    fn add(self, rhs: Self) -> Self::Output {
1517        Self(self.0 + rhs.0)
1518    }
1519}
1520
1521impl AddAssign for FoldOffset {
1522    fn add_assign(&mut self, rhs: Self) {
1523        self.0 += rhs.0;
1524    }
1525}
1526
1527impl Sub for FoldOffset {
1528    type Output = Self;
1529
1530    fn sub(self, rhs: Self) -> Self::Output {
1531        Self(self.0 - rhs.0)
1532    }
1533}
1534
1535impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1536    fn zero(_cx: ()) -> Self {
1537        Default::default()
1538    }
1539
1540    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1541        self.0 += &summary.output.len;
1542    }
1543}
1544
1545impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayPoint {
1546    fn zero(_cx: ()) -> Self {
1547        Default::default()
1548    }
1549
1550    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1551        self.0 += &summary.input.lines;
1552    }
1553}
1554
1555impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayOffset {
1556    fn zero(_cx: ()) -> Self {
1557        Default::default()
1558    }
1559
1560    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1561        self.0 += &summary.input.len;
1562    }
1563}
1564
1565pub type FoldEdit = Edit<FoldOffset>;
1566
1567#[cfg(test)]
1568mod tests {
1569    use super::*;
1570    use crate::{MultiBuffer, ToPoint, display_map::inlay_map::InlayMap};
1571    use Bias::{Left, Right};
1572    use collections::HashSet;
1573    use rand::prelude::*;
1574    use settings::SettingsStore;
1575    use std::{env, mem};
1576    use text::Patch;
1577    use util::RandomCharIter;
1578    use util::test::sample_text;
1579
1580    #[gpui::test]
1581    fn test_basic_folds(cx: &mut gpui::App) {
1582        init_test(cx);
1583        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1584        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1585        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1586        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1587        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1588
1589        let (mut writer, _, _) = map.write(inlay_snapshot, vec![]);
1590        let (snapshot2, edits) = writer.fold(vec![
1591            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1592            (Point::new(2, 4)..Point::new(4, 1), FoldPlaceholder::test()),
1593        ]);
1594        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1595        assert_eq!(
1596            edits,
1597            &[
1598                FoldEdit {
1599                    old: FoldOffset(2)..FoldOffset(16),
1600                    new: FoldOffset(2)..FoldOffset(5),
1601                },
1602                FoldEdit {
1603                    old: FoldOffset(18)..FoldOffset(29),
1604                    new: FoldOffset(7)..FoldOffset(10)
1605                },
1606            ]
1607        );
1608
1609        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1610            buffer.edit(
1611                vec![
1612                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1613                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1614                ],
1615                None,
1616                cx,
1617            );
1618            buffer.snapshot(cx)
1619        });
1620
1621        let (inlay_snapshot, inlay_edits) =
1622            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1623        let (snapshot3, edits) = map.read(inlay_snapshot, inlay_edits);
1624        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1625        assert_eq!(
1626            edits,
1627            &[
1628                FoldEdit {
1629                    old: FoldOffset(0)..FoldOffset(1),
1630                    new: FoldOffset(0)..FoldOffset(3),
1631                },
1632                FoldEdit {
1633                    old: FoldOffset(6)..FoldOffset(6),
1634                    new: FoldOffset(8)..FoldOffset(11),
1635                },
1636            ]
1637        );
1638
1639        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1640            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1641            buffer.snapshot(cx)
1642        });
1643        let (inlay_snapshot, inlay_edits) =
1644            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1645        let (snapshot4, _) = map.read(inlay_snapshot.clone(), inlay_edits);
1646        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1647
1648        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1649        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1650        let (snapshot5, _) = map.read(inlay_snapshot.clone(), vec![]);
1651        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1652
1653        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1654        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1655        let (snapshot6, _) = map.read(inlay_snapshot, vec![]);
1656        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1657    }
1658
1659    #[gpui::test]
1660    fn test_adjacent_folds(cx: &mut gpui::App) {
1661        init_test(cx);
1662        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1663        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1664        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1665        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1666
1667        {
1668            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1669
1670            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1671            writer.fold(vec![(5..8, FoldPlaceholder::test())]);
1672            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1673            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1674
1675            // Create an fold adjacent to the start of the first fold.
1676            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1677            writer.fold(vec![
1678                (0..1, FoldPlaceholder::test()),
1679                (2..5, FoldPlaceholder::test()),
1680            ]);
1681            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1682            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1683
1684            // Create an fold adjacent to the end of the first fold.
1685            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1686            writer.fold(vec![
1687                (11..11, FoldPlaceholder::test()),
1688                (8..10, FoldPlaceholder::test()),
1689            ]);
1690            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1691            assert_eq!(snapshot.text(), "⋯b⋯kl");
1692        }
1693
1694        {
1695            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1696
1697            // Create two adjacent folds.
1698            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1699            writer.fold(vec![
1700                (0..2, FoldPlaceholder::test()),
1701                (2..5, FoldPlaceholder::test()),
1702            ]);
1703            let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1704            assert_eq!(snapshot.text(), "⋯fghijkl");
1705
1706            // Edit within one of the folds.
1707            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1708                buffer.edit([(0..1, "12345")], None, cx);
1709                buffer.snapshot(cx)
1710            });
1711            let (inlay_snapshot, inlay_edits) =
1712                inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1713            let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1714            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1715        }
1716    }
1717
1718    #[gpui::test]
1719    fn test_overlapping_folds(cx: &mut gpui::App) {
1720        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1721        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1722        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1723        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1724        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1725        writer.fold(vec![
1726            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1727            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1728            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1729            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1730        ]);
1731        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1732        assert_eq!(snapshot.text(), "aa⋯eeeee");
1733    }
1734
1735    #[gpui::test]
1736    fn test_merging_folds_via_edit(cx: &mut gpui::App) {
1737        init_test(cx);
1738        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1739        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1740        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1741        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1742        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1743
1744        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1745        writer.fold(vec![
1746            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1747            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1748        ]);
1749        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1750        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1751
1752        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1753            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1754            buffer.snapshot(cx)
1755        });
1756        let (inlay_snapshot, inlay_edits) =
1757            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1758        let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1759        assert_eq!(snapshot.text(), "aa⋯eeeee");
1760    }
1761
1762    #[gpui::test]
1763    fn test_folds_in_range(cx: &mut gpui::App) {
1764        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1765        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1766        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1767        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1768
1769        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1770        writer.fold(vec![
1771            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1772            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1773            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1774            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1775        ]);
1776        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1777        let fold_ranges = snapshot
1778            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1779            .map(|fold| {
1780                fold.range.start.to_point(&buffer_snapshot)
1781                    ..fold.range.end.to_point(&buffer_snapshot)
1782            })
1783            .collect::<Vec<_>>();
1784        assert_eq!(
1785            fold_ranges,
1786            vec![
1787                Point::new(0, 2)..Point::new(2, 2),
1788                Point::new(1, 2)..Point::new(3, 2)
1789            ]
1790        );
1791    }
1792
1793    #[gpui::test(iterations = 100)]
1794    fn test_random_folds(cx: &mut gpui::App, mut rng: StdRng) {
1795        init_test(cx);
1796        let operations = env::var("OPERATIONS")
1797            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1798            .unwrap_or(10);
1799
1800        let len = rng.random_range(0..10);
1801        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1802        let buffer = if rng.random() {
1803            MultiBuffer::build_simple(&text, cx)
1804        } else {
1805            MultiBuffer::build_random(&mut rng, cx)
1806        };
1807        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1808        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1809        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1810
1811        let (mut initial_snapshot, _) = map.read(inlay_snapshot, vec![]);
1812        let mut snapshot_edits = Vec::new();
1813
1814        let mut next_inlay_id = 0;
1815        for _ in 0..operations {
1816            log::info!("text: {:?}", buffer_snapshot.text());
1817            let mut buffer_edits = Vec::new();
1818            let mut inlay_edits = Vec::new();
1819            match rng.random_range(0..=100) {
1820                0..=39 => {
1821                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1822                }
1823                40..=59 => {
1824                    let (_, edits) = inlay_map.randomly_mutate(&mut next_inlay_id, &mut rng);
1825                    inlay_edits = edits;
1826                }
1827                _ => buffer.update(cx, |buffer, cx| {
1828                    let subscription = buffer.subscribe();
1829                    let edit_count = rng.random_range(1..=5);
1830                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1831                    buffer_snapshot = buffer.snapshot(cx);
1832                    let edits = subscription.consume().into_inner();
1833                    log::info!("editing {:?}", edits);
1834                    buffer_edits.extend(edits);
1835                }),
1836            };
1837
1838            let (inlay_snapshot, new_inlay_edits) =
1839                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
1840            log::info!("inlay text {:?}", inlay_snapshot.text());
1841
1842            let inlay_edits = Patch::new(inlay_edits)
1843                .compose(new_inlay_edits)
1844                .into_inner();
1845            let (snapshot, edits) = map.read(inlay_snapshot.clone(), inlay_edits);
1846            snapshot_edits.push((snapshot.clone(), edits));
1847
1848            let mut expected_text: String = inlay_snapshot.text().to_string();
1849            for fold_range in map.merged_folds().into_iter().rev() {
1850                let fold_inlay_start = inlay_snapshot.to_inlay_offset(fold_range.start);
1851                let fold_inlay_end = inlay_snapshot.to_inlay_offset(fold_range.end);
1852                expected_text.replace_range(fold_inlay_start.0..fold_inlay_end.0, "");
1853            }
1854
1855            assert_eq!(snapshot.text(), expected_text);
1856            log::info!(
1857                "fold text {:?} ({} lines)",
1858                expected_text,
1859                expected_text.matches('\n').count() + 1
1860            );
1861
1862            let mut prev_row = 0;
1863            let mut expected_buffer_rows = Vec::new();
1864            for fold_range in map.merged_folds() {
1865                let fold_start = inlay_snapshot
1866                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.start))
1867                    .row();
1868                let fold_end = inlay_snapshot
1869                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.end))
1870                    .row();
1871                expected_buffer_rows.extend(
1872                    inlay_snapshot
1873                        .row_infos(prev_row)
1874                        .take((1 + fold_start - prev_row) as usize),
1875                );
1876                prev_row = 1 + fold_end;
1877            }
1878            expected_buffer_rows.extend(inlay_snapshot.row_infos(prev_row));
1879
1880            assert_eq!(
1881                expected_buffer_rows.len(),
1882                expected_text.matches('\n').count() + 1,
1883                "wrong expected buffer rows {:?}. text: {:?}",
1884                expected_buffer_rows,
1885                expected_text
1886            );
1887
1888            for (output_row, line) in expected_text.lines().enumerate() {
1889                let line_len = snapshot.line_len(output_row as u32);
1890                assert_eq!(line_len, line.len() as u32);
1891            }
1892
1893            let longest_row = snapshot.longest_row();
1894            let longest_char_column = expected_text
1895                .split('\n')
1896                .nth(longest_row as usize)
1897                .unwrap()
1898                .chars()
1899                .count();
1900            let mut fold_point = FoldPoint::new(0, 0);
1901            let mut fold_offset = FoldOffset(0);
1902            let mut char_column = 0;
1903            for c in expected_text.chars() {
1904                let inlay_point = fold_point.to_inlay_point(&snapshot);
1905                let inlay_offset = fold_offset.to_inlay_offset(&snapshot);
1906                assert_eq!(
1907                    snapshot.to_fold_point(inlay_point, Right),
1908                    fold_point,
1909                    "{:?} -> fold point",
1910                    inlay_point,
1911                );
1912                assert_eq!(
1913                    inlay_snapshot.to_offset(inlay_point),
1914                    inlay_offset,
1915                    "inlay_snapshot.to_offset({:?})",
1916                    inlay_point,
1917                );
1918                assert_eq!(
1919                    fold_point.to_offset(&snapshot),
1920                    fold_offset,
1921                    "fold_point.to_offset({:?})",
1922                    fold_point,
1923                );
1924
1925                if c == '\n' {
1926                    *fold_point.row_mut() += 1;
1927                    *fold_point.column_mut() = 0;
1928                    char_column = 0;
1929                } else {
1930                    *fold_point.column_mut() += c.len_utf8() as u32;
1931                    char_column += 1;
1932                }
1933                fold_offset.0 += c.len_utf8();
1934                if char_column > longest_char_column {
1935                    panic!(
1936                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1937                        longest_row,
1938                        longest_char_column,
1939                        fold_point.row(),
1940                        char_column
1941                    );
1942                }
1943            }
1944
1945            for _ in 0..5 {
1946                let mut start = snapshot.clip_offset(
1947                    FoldOffset(rng.random_range(0..=snapshot.len().0)),
1948                    Bias::Left,
1949                );
1950                let mut end = snapshot.clip_offset(
1951                    FoldOffset(rng.random_range(0..=snapshot.len().0)),
1952                    Bias::Right,
1953                );
1954                if start > end {
1955                    mem::swap(&mut start, &mut end);
1956                }
1957
1958                let text = &expected_text[start.0..end.0];
1959                assert_eq!(
1960                    snapshot
1961                        .chunks(start..end, false, Highlights::default())
1962                        .map(|c| c.text)
1963                        .collect::<String>(),
1964                    text,
1965                );
1966            }
1967
1968            let mut fold_row = 0;
1969            while fold_row < expected_buffer_rows.len() as u32 {
1970                assert_eq!(
1971                    snapshot.row_infos(fold_row).collect::<Vec<_>>(),
1972                    expected_buffer_rows[(fold_row as usize)..],
1973                    "wrong buffer rows starting at fold row {}",
1974                    fold_row,
1975                );
1976                fold_row += 1;
1977            }
1978
1979            let folded_buffer_rows = map
1980                .merged_folds()
1981                .iter()
1982                .flat_map(|fold_range| {
1983                    let start_row = fold_range.start.to_point(&buffer_snapshot).row;
1984                    let end = fold_range.end.to_point(&buffer_snapshot);
1985                    if end.column == 0 {
1986                        start_row..end.row
1987                    } else {
1988                        start_row..end.row + 1
1989                    }
1990                })
1991                .collect::<HashSet<_>>();
1992            for row in 0..=buffer_snapshot.max_point().row {
1993                assert_eq!(
1994                    snapshot.is_line_folded(MultiBufferRow(row)),
1995                    folded_buffer_rows.contains(&row),
1996                    "expected buffer row {}{} to be folded",
1997                    row,
1998                    if folded_buffer_rows.contains(&row) {
1999                        ""
2000                    } else {
2001                        " not"
2002                    }
2003                );
2004            }
2005
2006            for _ in 0..5 {
2007                let end =
2008                    buffer_snapshot.clip_offset(rng.random_range(0..=buffer_snapshot.len()), Right);
2009                let start = buffer_snapshot.clip_offset(rng.random_range(0..=end), Left);
2010                let expected_folds = map
2011                    .snapshot
2012                    .folds
2013                    .items(&buffer_snapshot)
2014                    .into_iter()
2015                    .filter(|fold| {
2016                        let start = buffer_snapshot.anchor_before(start);
2017                        let end = buffer_snapshot.anchor_after(end);
2018                        start.cmp(&fold.range.end, &buffer_snapshot) == Ordering::Less
2019                            && end.cmp(&fold.range.start, &buffer_snapshot) == Ordering::Greater
2020                    })
2021                    .collect::<Vec<_>>();
2022
2023                assert_eq!(
2024                    snapshot
2025                        .folds_in_range(start..end)
2026                        .cloned()
2027                        .collect::<Vec<_>>(),
2028                    expected_folds
2029                );
2030            }
2031
2032            let text = snapshot.text();
2033            for _ in 0..5 {
2034                let start_row = rng.random_range(0..=snapshot.max_point().row());
2035                let start_column = rng.random_range(0..=snapshot.line_len(start_row));
2036                let end_row = rng.random_range(0..=snapshot.max_point().row());
2037                let end_column = rng.random_range(0..=snapshot.line_len(end_row));
2038                let mut start =
2039                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
2040                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
2041                if start > end {
2042                    mem::swap(&mut start, &mut end);
2043                }
2044
2045                let lines = start..end;
2046                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
2047                assert_eq!(
2048                    snapshot.text_summary_for_range(lines),
2049                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
2050                )
2051            }
2052
2053            let mut text = initial_snapshot.text();
2054            for (snapshot, edits) in snapshot_edits.drain(..) {
2055                let new_text = snapshot.text();
2056                for edit in edits {
2057                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
2058                    let new_bytes = edit.new.start.0..edit.new.end.0;
2059                    text.replace_range(old_bytes, &new_text[new_bytes]);
2060                }
2061
2062                assert_eq!(text, new_text);
2063                initial_snapshot = snapshot;
2064            }
2065        }
2066    }
2067
2068    #[gpui::test]
2069    fn test_buffer_rows(cx: &mut gpui::App) {
2070        let text = sample_text(6, 6, 'a') + "\n";
2071        let buffer = MultiBuffer::build_simple(&text, cx);
2072
2073        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2074        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
2075        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
2076
2077        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
2078        writer.fold(vec![
2079            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
2080            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
2081        ]);
2082
2083        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
2084        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
2085        assert_eq!(
2086            snapshot
2087                .row_infos(0)
2088                .map(|info| info.buffer_row)
2089                .collect::<Vec<_>>(),
2090            [Some(0), Some(3), Some(5), Some(6)]
2091        );
2092        assert_eq!(
2093            snapshot
2094                .row_infos(3)
2095                .map(|info| info.buffer_row)
2096                .collect::<Vec<_>>(),
2097            [Some(6)]
2098        );
2099    }
2100
2101    #[gpui::test(iterations = 100)]
2102    fn test_random_chunk_bitmaps(cx: &mut gpui::App, mut rng: StdRng) {
2103        init_test(cx);
2104
2105        // Generate random buffer using existing test infrastructure
2106        let text_len = rng.random_range(0..10000);
2107        let buffer = if rng.random() {
2108            let text = RandomCharIter::new(&mut rng)
2109                .take(text_len)
2110                .collect::<String>();
2111            MultiBuffer::build_simple(&text, cx)
2112        } else {
2113            MultiBuffer::build_random(&mut rng, cx)
2114        };
2115        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2116        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
2117        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
2118
2119        // Perform random mutations
2120        let mutation_count = rng.random_range(1..10);
2121        for _ in 0..mutation_count {
2122            fold_map.randomly_mutate(&mut rng);
2123        }
2124
2125        let (snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
2126
2127        // Get all chunks and verify their bitmaps
2128        let chunks = snapshot.chunks(
2129            FoldOffset(0)..FoldOffset(snapshot.len().0),
2130            false,
2131            Highlights::default(),
2132        );
2133
2134        for chunk in chunks {
2135            let chunk_text = chunk.text;
2136            let chars_bitmap = chunk.chars;
2137            let tabs_bitmap = chunk.tabs;
2138
2139            // Check empty chunks have empty bitmaps
2140            if chunk_text.is_empty() {
2141                assert_eq!(
2142                    chars_bitmap, 0,
2143                    "Empty chunk should have empty chars bitmap"
2144                );
2145                assert_eq!(tabs_bitmap, 0, "Empty chunk should have empty tabs bitmap");
2146                continue;
2147            }
2148
2149            // Verify that chunk text doesn't exceed 128 bytes
2150            assert!(
2151                chunk_text.len() <= 128,
2152                "Chunk text length {} exceeds 128 bytes",
2153                chunk_text.len()
2154            );
2155
2156            // Verify chars bitmap
2157            let char_indices = chunk_text
2158                .char_indices()
2159                .map(|(i, _)| i)
2160                .collect::<Vec<_>>();
2161
2162            for byte_idx in 0..chunk_text.len() {
2163                let should_have_bit = char_indices.contains(&byte_idx);
2164                let has_bit = chars_bitmap & (1 << byte_idx) != 0;
2165
2166                if has_bit != should_have_bit {
2167                    eprintln!("Chunk text bytes: {:?}", chunk_text.as_bytes());
2168                    eprintln!("Char indices: {:?}", char_indices);
2169                    eprintln!("Chars bitmap: {:#b}", chars_bitmap);
2170                    assert_eq!(
2171                        has_bit, should_have_bit,
2172                        "Chars bitmap mismatch at byte index {} in chunk {:?}. Expected bit: {}, Got bit: {}",
2173                        byte_idx, chunk_text, should_have_bit, has_bit
2174                    );
2175                }
2176            }
2177
2178            // Verify tabs bitmap
2179            for (byte_idx, byte) in chunk_text.bytes().enumerate() {
2180                let is_tab = byte == b'\t';
2181                let has_bit = tabs_bitmap & (1 << byte_idx) != 0;
2182
2183                assert_eq!(
2184                    has_bit, is_tab,
2185                    "Tabs bitmap mismatch at byte index {} in chunk {:?}. Byte: {:?}, Expected bit: {}, Got bit: {}",
2186                    byte_idx, chunk_text, byte as char, is_tab, has_bit
2187                );
2188            }
2189        }
2190    }
2191
2192    fn init_test(cx: &mut gpui::App) {
2193        let store = SettingsStore::test(cx);
2194        cx.set_global(store);
2195    }
2196
2197    impl FoldMap {
2198        fn merged_folds(&self) -> Vec<Range<usize>> {
2199            let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2200            let buffer = &inlay_snapshot.buffer;
2201            let mut folds = self.snapshot.folds.items(buffer);
2202            // Ensure sorting doesn't change how folds get merged and displayed.
2203            folds.sort_by(|a, b| a.range.cmp(&b.range, buffer));
2204            let mut folds = folds
2205                .iter()
2206                .map(|fold| fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer))
2207                .peekable();
2208
2209            let mut merged_folds = Vec::new();
2210            while let Some(mut fold_range) = folds.next() {
2211                while let Some(next_range) = folds.peek() {
2212                    if fold_range.end >= next_range.start {
2213                        if next_range.end > fold_range.end {
2214                            fold_range.end = next_range.end;
2215                        }
2216                        folds.next();
2217                    } else {
2218                        break;
2219                    }
2220                }
2221                if fold_range.end > fold_range.start {
2222                    merged_folds.push(fold_range);
2223                }
2224            }
2225            merged_folds
2226        }
2227
2228        pub fn randomly_mutate(
2229            &mut self,
2230            rng: &mut impl Rng,
2231        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
2232            let mut snapshot_edits = Vec::new();
2233            match rng.random_range(0..=100) {
2234                0..=39 if !self.snapshot.folds.is_empty() => {
2235                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2236                    let buffer = &inlay_snapshot.buffer;
2237                    let mut to_unfold = Vec::new();
2238                    for _ in 0..rng.random_range(1..=3) {
2239                        let end = buffer.clip_offset(rng.random_range(0..=buffer.len()), Right);
2240                        let start = buffer.clip_offset(rng.random_range(0..=end), Left);
2241                        to_unfold.push(start..end);
2242                    }
2243                    let inclusive = rng.random();
2244                    log::info!("unfolding {:?} (inclusive: {})", to_unfold, inclusive);
2245                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2246                    snapshot_edits.push((snapshot, edits));
2247                    let (snapshot, edits) = writer.unfold_intersecting(to_unfold, inclusive);
2248                    snapshot_edits.push((snapshot, edits));
2249                }
2250                _ => {
2251                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2252                    let buffer = &inlay_snapshot.buffer;
2253                    let mut to_fold = Vec::new();
2254                    for _ in 0..rng.random_range(1..=2) {
2255                        let end = buffer.clip_offset(rng.random_range(0..=buffer.len()), Right);
2256                        let start = buffer.clip_offset(rng.random_range(0..=end), Left);
2257                        to_fold.push((start..end, FoldPlaceholder::test()));
2258                    }
2259                    log::info!("folding {:?}", to_fold);
2260                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2261                    snapshot_edits.push((snapshot, edits));
2262                    let (snapshot, edits) = writer.fold(to_fold);
2263                    snapshot_edits.push((snapshot, edits));
2264                }
2265            }
2266            snapshot_edits
2267        }
2268    }
2269}