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.filter_snapshot.buffer_snapshot;
 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            // FIXME we should ignore any folds that start or end in a filtered region
 163
 164            folds.push(Fold {
 165                id: FoldId(post_inc(&mut self.0.next_fold_id.0)),
 166                range: fold_range,
 167                placeholder: fold_text,
 168            });
 169
 170            let filter_range = snapshot.filter_snapshot.to_filter_offset(range.start)
 171                ..snapshot.filter_snapshot.to_filter_offset(range.end);
 172            let inlay_range = snapshot.to_inlay_offset(filter_range.start)
 173                ..snapshot.to_inlay_offset(filter_range.end);
 174            edits.push(InlayEdit {
 175                old: inlay_range.clone(),
 176                new: inlay_range,
 177            });
 178        }
 179
 180        let buffer = &snapshot.filter_snapshot.buffer_snapshot;
 181        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(&a.range, &b.range, buffer));
 182
 183        self.0.snapshot.folds = {
 184            let mut new_tree = SumTree::new(buffer);
 185            let mut cursor = self.0.snapshot.folds.cursor::<FoldRange>(buffer);
 186            for fold in folds {
 187                self.0.snapshot.fold_metadata_by_id.insert(
 188                    fold.id,
 189                    FoldMetadata {
 190                        range: fold.range.clone(),
 191                        width: None,
 192                    },
 193                );
 194                new_tree.append(cursor.slice(&fold.range, Bias::Right), buffer);
 195                new_tree.push(fold, buffer);
 196            }
 197            new_tree.append(cursor.suffix(), buffer);
 198            new_tree
 199        };
 200
 201        let edits = consolidate_inlay_edits(edits);
 202        let edits = self.0.sync(snapshot.clone(), edits);
 203        (self.0.snapshot.clone(), edits)
 204    }
 205
 206    /// Removes any folds with the given ranges.
 207    pub(crate) fn remove_folds<T: ToOffset>(
 208        &mut self,
 209        ranges: impl IntoIterator<Item = Range<T>>,
 210        type_id: TypeId,
 211    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 212        self.remove_folds_with(
 213            ranges,
 214            |fold| fold.placeholder.type_tag == Some(type_id),
 215            false,
 216        )
 217    }
 218
 219    /// Removes any folds whose ranges intersect the given ranges.
 220    pub(crate) fn unfold_intersecting<T: ToOffset>(
 221        &mut self,
 222        ranges: impl IntoIterator<Item = Range<T>>,
 223        inclusive: bool,
 224    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 225        self.remove_folds_with(ranges, |_| true, inclusive)
 226    }
 227
 228    /// Removes any folds that intersect the given ranges and for which the given predicate
 229    /// returns true.
 230    fn remove_folds_with<T: ToOffset>(
 231        &mut self,
 232        ranges: impl IntoIterator<Item = Range<T>>,
 233        should_unfold: impl Fn(&Fold) -> bool,
 234        inclusive: bool,
 235    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 236        let mut edits = Vec::new();
 237        let mut fold_ixs_to_delete = Vec::new();
 238        let snapshot = self.0.snapshot.inlay_snapshot.clone();
 239        let buffer = &snapshot.filter_snapshot.buffer_snapshot;
 240        for range in ranges.into_iter() {
 241            let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 242            let mut folds_cursor =
 243                intersecting_folds(&snapshot, &self.0.snapshot.folds, range.clone(), inclusive);
 244            while let Some(fold) = folds_cursor.item() {
 245                let offset_range =
 246                    fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer);
 247                let filter_range = snapshot
 248                    .filter_snapshot
 249                    .to_filter_offset(offset_range.start)
 250                    ..snapshot.filter_snapshot.to_filter_offset(offset_range.end);
 251                if should_unfold(fold) {
 252                    if offset_range.end > offset_range.start {
 253                        let inlay_range = snapshot.to_inlay_offset(filter_range.start)
 254                            ..snapshot.to_inlay_offset(filter_range.end);
 255                        edits.push(InlayEdit {
 256                            old: inlay_range.clone(),
 257                            new: inlay_range,
 258                        });
 259                    }
 260                    fold_ixs_to_delete.push(*folds_cursor.start());
 261                    self.0.snapshot.fold_metadata_by_id.remove(&fold.id);
 262                }
 263                folds_cursor.next();
 264            }
 265        }
 266
 267        fold_ixs_to_delete.sort_unstable();
 268        fold_ixs_to_delete.dedup();
 269
 270        self.0.snapshot.folds = {
 271            let mut cursor = self.0.snapshot.folds.cursor::<usize>(buffer);
 272            let mut folds = SumTree::new(buffer);
 273            for fold_ix in fold_ixs_to_delete {
 274                folds.append(cursor.slice(&fold_ix, Bias::Right), buffer);
 275                cursor.next();
 276            }
 277            folds.append(cursor.suffix(), buffer);
 278            folds
 279        };
 280
 281        let edits = consolidate_inlay_edits(edits);
 282        let edits = self.0.sync(snapshot.clone(), edits);
 283        (self.0.snapshot.clone(), edits)
 284    }
 285
 286    pub(crate) fn update_fold_widths(
 287        &mut self,
 288        new_widths: impl IntoIterator<Item = (ChunkRendererId, Pixels)>,
 289    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 290        let mut edits = Vec::new();
 291        let inlay_snapshot = self.0.snapshot.inlay_snapshot.clone();
 292        let buffer = &inlay_snapshot.filter_snapshot.buffer_snapshot;
 293
 294        for (id, new_width) in new_widths {
 295            let ChunkRendererId::Fold(id) = id else {
 296                continue;
 297            };
 298            if let Some(metadata) = self.0.snapshot.fold_metadata_by_id.get(&id).cloned()
 299                && Some(new_width) != metadata.width
 300            {
 301                let buffer_start = metadata.range.start.to_offset(buffer);
 302                let buffer_end = metadata.range.end.to_offset(buffer);
 303                let filter_range = inlay_snapshot
 304                    .filter_snapshot
 305                    .to_filter_offset(buffer_start)
 306                    ..inlay_snapshot.filter_snapshot.to_filter_offset(buffer_end);
 307                let inlay_range = inlay_snapshot.to_inlay_offset(filter_range.start)
 308                    ..inlay_snapshot.to_inlay_offset(filter_range.end);
 309                edits.push(InlayEdit {
 310                    old: inlay_range.clone(),
 311                    new: inlay_range.clone(),
 312                });
 313
 314                self.0.snapshot.fold_metadata_by_id.insert(
 315                    id,
 316                    FoldMetadata {
 317                        range: metadata.range,
 318                        width: Some(new_width),
 319                    },
 320                );
 321            }
 322        }
 323
 324        let edits = consolidate_inlay_edits(edits);
 325        let edits = self.0.sync(inlay_snapshot, edits);
 326        (self.0.snapshot.clone(), edits)
 327    }
 328}
 329
 330/// Decides where the fold indicators should be; also tracks parts of a source file that are currently folded.
 331///
 332/// See the [`display_map` module documentation](crate::display_map) for more information.
 333pub struct FoldMap {
 334    snapshot: FoldSnapshot,
 335    next_fold_id: FoldId,
 336}
 337
 338impl FoldMap {
 339    pub fn new(inlay_snapshot: InlaySnapshot) -> (Self, FoldSnapshot) {
 340        let this = Self {
 341            snapshot: FoldSnapshot {
 342                folds: SumTree::new(&inlay_snapshot.filter_snapshot.buffer_snapshot),
 343                transforms: SumTree::from_item(
 344                    Transform {
 345                        summary: TransformSummary {
 346                            input: inlay_snapshot.text_summary(),
 347                            output: inlay_snapshot.text_summary(),
 348                        },
 349                        placeholder: None,
 350                    },
 351                    (),
 352                ),
 353                inlay_snapshot: inlay_snapshot,
 354                version: 0,
 355                fold_metadata_by_id: TreeMap::default(),
 356            },
 357            next_fold_id: FoldId::default(),
 358        };
 359        let snapshot = this.snapshot.clone();
 360        (this, snapshot)
 361    }
 362
 363    pub fn read(
 364        &mut self,
 365        inlay_snapshot: InlaySnapshot,
 366        edits: Vec<InlayEdit>,
 367    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 368        let edits = self.sync(inlay_snapshot, edits);
 369        self.check_invariants();
 370        (self.snapshot.clone(), edits)
 371    }
 372
 373    pub(crate) fn write(
 374        &mut self,
 375        inlay_snapshot: InlaySnapshot,
 376        edits: Vec<InlayEdit>,
 377    ) -> (FoldMapWriter<'_>, FoldSnapshot, Vec<FoldEdit>) {
 378        let (snapshot, edits) = self.read(inlay_snapshot, edits);
 379        (FoldMapWriter(self), snapshot, edits)
 380    }
 381
 382    fn check_invariants(&self) {
 383        if cfg!(test) {
 384            assert_eq!(
 385                self.snapshot.transforms.summary().input.len,
 386                self.snapshot.inlay_snapshot.len().0,
 387                "transform tree does not match inlay snapshot's length"
 388            );
 389
 390            let mut prev_transform_isomorphic = false;
 391            for transform in self.snapshot.transforms.iter() {
 392                if !transform.is_fold() && prev_transform_isomorphic {
 393                    panic!(
 394                        "found adjacent isomorphic transforms: {:?}",
 395                        self.snapshot.transforms.items(())
 396                    );
 397                }
 398                prev_transform_isomorphic = !transform.is_fold();
 399            }
 400
 401            let mut folds = self.snapshot.folds.iter().peekable();
 402            while let Some(fold) = folds.next() {
 403                if let Some(next_fold) = folds.peek() {
 404                    let comparison = fold.range.cmp(&next_fold.range, self.snapshot.buffer());
 405                    assert!(comparison.is_le());
 406                }
 407            }
 408        }
 409    }
 410
 411    fn sync(
 412        &mut self,
 413        inlay_snapshot: InlaySnapshot,
 414        inlay_edits: Vec<InlayEdit>,
 415    ) -> Vec<FoldEdit> {
 416        if inlay_edits.is_empty() {
 417            if self.snapshot.inlay_snapshot.version != inlay_snapshot.version {
 418                self.snapshot.version += 1;
 419            }
 420            self.snapshot.inlay_snapshot = inlay_snapshot;
 421            Vec::new()
 422        } else {
 423            let mut inlay_edits_iter = inlay_edits.iter().cloned().peekable();
 424
 425            let mut new_transforms = SumTree::<Transform>::default();
 426            let mut cursor = self.snapshot.transforms.cursor::<InlayOffset>(());
 427            cursor.seek(&InlayOffset(0), Bias::Right);
 428
 429            while let Some(mut edit) = inlay_edits_iter.next() {
 430                if let Some(item) = cursor.item()
 431                    && !item.is_fold()
 432                {
 433                    new_transforms.update_last(
 434                        |transform| {
 435                            if !transform.is_fold() {
 436                                transform.summary.add_summary(&item.summary, ());
 437                                cursor.next();
 438                            }
 439                        },
 440                        (),
 441                    );
 442                }
 443                new_transforms.append(cursor.slice(&edit.old.start, Bias::Left), ());
 444                edit.new.start -= edit.old.start - *cursor.start();
 445                edit.old.start = *cursor.start();
 446
 447                cursor.seek(&edit.old.end, Bias::Right);
 448                cursor.next();
 449
 450                let mut delta = edit.new_len().0 as isize - edit.old_len().0 as isize;
 451                loop {
 452                    edit.old.end = *cursor.start();
 453
 454                    if let Some(next_edit) = inlay_edits_iter.peek() {
 455                        if next_edit.old.start > edit.old.end {
 456                            break;
 457                        }
 458
 459                        let next_edit = inlay_edits_iter.next().unwrap();
 460                        delta += next_edit.new_len().0 as isize - next_edit.old_len().0 as isize;
 461
 462                        if next_edit.old.end >= edit.old.end {
 463                            edit.old.end = next_edit.old.end;
 464                            cursor.seek(&edit.old.end, Bias::Right);
 465                            cursor.next();
 466                        }
 467                    } else {
 468                        break;
 469                    }
 470                }
 471
 472                edit.new.end =
 473                    InlayOffset(((edit.new.start + edit.old_len()).0 as isize + delta) as usize);
 474
 475                let filter_offset = inlay_snapshot.to_filter_offset(edit.new.start);
 476                let anchor = inlay_snapshot
 477                    .filter_snapshot
 478                    .buffer_snapshot
 479                    .anchor_before(
 480                        inlay_snapshot
 481                            .filter_snapshot
 482                            .to_buffer_offset(filter_offset, Bias::Left),
 483                    );
 484                let mut folds_cursor = self
 485                    .snapshot
 486                    .folds
 487                    .cursor::<FoldRange>(&inlay_snapshot.filter_snapshot.buffer_snapshot);
 488                folds_cursor.seek(&FoldRange(anchor..Anchor::max()), Bias::Left);
 489
 490                let mut folds = iter::from_fn({
 491                    let inlay_snapshot = &inlay_snapshot;
 492                    move || {
 493                        let item = folds_cursor.item().map(|fold| {
 494                            let buffer_start = fold
 495                                .range
 496                                .start
 497                                .to_offset(&inlay_snapshot.filter_snapshot.buffer_snapshot);
 498                            let buffer_end = fold
 499                                .range
 500                                .end
 501                                .to_offset(&inlay_snapshot.filter_snapshot.buffer_snapshot);
 502                            let filter_range = inlay_snapshot
 503                                .filter_snapshot
 504                                .to_filter_offset(buffer_start)
 505                                ..inlay_snapshot.filter_snapshot.to_filter_offset(buffer_end);
 506                            (
 507                                fold.clone(),
 508                                inlay_snapshot.to_inlay_offset(filter_range.start)
 509                                    ..inlay_snapshot.to_inlay_offset(filter_range.end),
 510                            )
 511                        });
 512                        folds_cursor.next();
 513                        item
 514                    }
 515                })
 516                .peekable();
 517
 518                while folds
 519                    .peek()
 520                    .is_some_and(|(_, fold_range)| fold_range.start < edit.new.end)
 521                {
 522                    let (fold, mut fold_range) = folds.next().unwrap();
 523                    let sum = new_transforms.summary();
 524
 525                    assert!(fold_range.start.0 >= sum.input.len);
 526
 527                    while folds.peek().is_some_and(|(next_fold, next_fold_range)| {
 528                        next_fold_range.start < fold_range.end
 529                            || (next_fold_range.start == fold_range.end
 530                                && fold.placeholder.merge_adjacent
 531                                && next_fold.placeholder.merge_adjacent)
 532                    }) {
 533                        let (_, next_fold_range) = folds.next().unwrap();
 534                        if next_fold_range.end > fold_range.end {
 535                            fold_range.end = next_fold_range.end;
 536                        }
 537                    }
 538
 539                    if fold_range.start.0 > sum.input.len {
 540                        let text_summary = inlay_snapshot
 541                            .text_summary_for_range(InlayOffset(sum.input.len)..fold_range.start);
 542                        push_isomorphic(&mut new_transforms, text_summary);
 543                    }
 544
 545                    if fold_range.end > fold_range.start {
 546                        const ELLIPSIS: &str = "";
 547
 548                        let fold_id = fold.id;
 549                        new_transforms.push(
 550                            Transform {
 551                                summary: TransformSummary {
 552                                    output: TextSummary::from(ELLIPSIS),
 553                                    input: inlay_snapshot
 554                                        .text_summary_for_range(fold_range.start..fold_range.end),
 555                                },
 556                                placeholder: Some(TransformPlaceholder {
 557                                    text: ELLIPSIS,
 558                                    chars: 1,
 559                                    renderer: ChunkRenderer {
 560                                        id: ChunkRendererId::Fold(fold.id),
 561                                        render: Arc::new(move |cx| {
 562                                            (fold.placeholder.render)(
 563                                                fold_id,
 564                                                fold.range.0.clone(),
 565                                                cx.context,
 566                                            )
 567                                        }),
 568                                        constrain_width: fold.placeholder.constrain_width,
 569                                        measured_width: self.snapshot.fold_width(&fold_id),
 570                                    },
 571                                }),
 572                            },
 573                            (),
 574                        );
 575                    }
 576                }
 577
 578                let sum = new_transforms.summary();
 579                if sum.input.len < edit.new.end.0 {
 580                    let text_summary = inlay_snapshot
 581                        .text_summary_for_range(InlayOffset(sum.input.len)..edit.new.end);
 582                    push_isomorphic(&mut new_transforms, text_summary);
 583                }
 584            }
 585
 586            new_transforms.append(cursor.suffix(), ());
 587            if new_transforms.is_empty() {
 588                let text_summary = inlay_snapshot.text_summary();
 589                push_isomorphic(&mut new_transforms, text_summary);
 590            }
 591
 592            drop(cursor);
 593
 594            let mut fold_edits = Vec::with_capacity(inlay_edits.len());
 595            {
 596                let mut old_transforms = self
 597                    .snapshot
 598                    .transforms
 599                    .cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 600                let mut new_transforms =
 601                    new_transforms.cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 602
 603                for mut edit in inlay_edits {
 604                    old_transforms.seek(&edit.old.start, Bias::Left);
 605                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 606                        edit.old.start = old_transforms.start().0;
 607                    }
 608                    let old_start =
 609                        old_transforms.start().1.0 + (edit.old.start - old_transforms.start().0).0;
 610
 611                    old_transforms.seek_forward(&edit.old.end, Bias::Right);
 612                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 613                        old_transforms.next();
 614                        edit.old.end = old_transforms.start().0;
 615                    }
 616                    let old_end =
 617                        old_transforms.start().1.0 + (edit.old.end - old_transforms.start().0).0;
 618
 619                    new_transforms.seek(&edit.new.start, Bias::Left);
 620                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 621                        edit.new.start = new_transforms.start().0;
 622                    }
 623                    let new_start =
 624                        new_transforms.start().1.0 + (edit.new.start - new_transforms.start().0).0;
 625
 626                    new_transforms.seek_forward(&edit.new.end, Bias::Right);
 627                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 628                        new_transforms.next();
 629                        edit.new.end = new_transforms.start().0;
 630                    }
 631                    let new_end =
 632                        new_transforms.start().1.0 + (edit.new.end - new_transforms.start().0).0;
 633
 634                    fold_edits.push(FoldEdit {
 635                        old: FoldOffset(old_start)..FoldOffset(old_end),
 636                        new: FoldOffset(new_start)..FoldOffset(new_end),
 637                    });
 638                }
 639
 640                fold_edits = consolidate_fold_edits(fold_edits);
 641            }
 642
 643            self.snapshot.transforms = new_transforms;
 644            self.snapshot.inlay_snapshot = inlay_snapshot;
 645            self.snapshot.version += 1;
 646            fold_edits
 647        }
 648    }
 649}
 650
 651#[derive(Clone)]
 652pub struct FoldSnapshot {
 653    pub inlay_snapshot: InlaySnapshot,
 654    transforms: SumTree<Transform>,
 655    folds: SumTree<Fold>,
 656    fold_metadata_by_id: TreeMap<FoldId, FoldMetadata>,
 657    pub version: usize,
 658}
 659
 660impl FoldSnapshot {
 661    pub fn buffer(&self) -> &MultiBufferSnapshot {
 662        &self.inlay_snapshot.filter_snapshot.buffer_snapshot
 663    }
 664
 665    fn fold_width(&self, fold_id: &FoldId) -> Option<Pixels> {
 666        self.fold_metadata_by_id.get(fold_id)?.width
 667    }
 668
 669    #[cfg(test)]
 670    pub fn text(&self) -> String {
 671        self.chunks(FoldOffset(0)..self.len(), false, Highlights::default())
 672            .map(|c| c.text)
 673            .collect()
 674    }
 675
 676    #[cfg(test)]
 677    pub fn fold_count(&self) -> usize {
 678        self.folds
 679            .items(&self.inlay_snapshot.filter_snapshot.buffer_snapshot)
 680            .len()
 681    }
 682
 683    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 684        let mut summary = TextSummary::default();
 685
 686        let mut cursor = self
 687            .transforms
 688            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 689        cursor.seek(&range.start, Bias::Right);
 690        if let Some(transform) = cursor.item() {
 691            let start_in_transform = range.start.0 - cursor.start().0.0;
 692            let end_in_transform = cmp::min(range.end, cursor.end().0).0 - cursor.start().0.0;
 693            if let Some(placeholder) = transform.placeholder.as_ref() {
 694                summary = TextSummary::from(
 695                    &placeholder.text
 696                        [start_in_transform.column as usize..end_in_transform.column as usize],
 697                );
 698            } else {
 699                let inlay_start = self
 700                    .inlay_snapshot
 701                    .to_offset(InlayPoint(cursor.start().1.0 + start_in_transform));
 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        if range.end > cursor.end().0 {
 712            cursor.next();
 713            summary += &cursor
 714                .summary::<_, TransformSummary>(&range.end, Bias::Right)
 715                .output;
 716            if let Some(transform) = cursor.item() {
 717                let end_in_transform = range.end.0 - cursor.start().0.0;
 718                if let Some(placeholder) = transform.placeholder.as_ref() {
 719                    summary +=
 720                        TextSummary::from(&placeholder.text[..end_in_transform.column as usize]);
 721                } else {
 722                    let inlay_start = self.inlay_snapshot.to_offset(cursor.start().1);
 723                    let inlay_end = self
 724                        .inlay_snapshot
 725                        .to_offset(InlayPoint(cursor.start().1.0 + end_in_transform));
 726                    summary += self
 727                        .inlay_snapshot
 728                        .text_summary_for_range(inlay_start..inlay_end);
 729                }
 730            }
 731        }
 732
 733        summary
 734    }
 735
 736    pub fn to_fold_point(&self, point: InlayPoint, bias: Bias) -> FoldPoint {
 737        let (start, end, item) = self
 738            .transforms
 739            .find::<Dimensions<InlayPoint, FoldPoint>, _>((), &point, Bias::Right);
 740        if item.is_some_and(|t| t.is_fold()) {
 741            if bias == Bias::Left || point == start.0 {
 742                start.1
 743            } else {
 744                end.1
 745            }
 746        } else {
 747            let overshoot = point.0 - start.0.0;
 748            FoldPoint(cmp::min(start.1.0 + overshoot, end.1.0))
 749        }
 750    }
 751
 752    pub fn len(&self) -> FoldOffset {
 753        FoldOffset(self.transforms.summary().output.len)
 754    }
 755
 756    pub fn line_len(&self, row: u32) -> u32 {
 757        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 758        let line_end = if row >= self.max_point().row() {
 759            self.len().0
 760        } else {
 761            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 762        };
 763        (line_end - line_start) as u32
 764    }
 765
 766    pub fn row_infos(&self, start_row: u32) -> FoldRows<'_> {
 767        if start_row > self.transforms.summary().output.lines.row {
 768            panic!("invalid display row {}", start_row);
 769        }
 770
 771        let fold_point = FoldPoint::new(start_row, 0);
 772        let mut cursor = self
 773            .transforms
 774            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 775        cursor.seek(&fold_point, Bias::Left);
 776
 777        let overshoot = fold_point.0 - cursor.start().0.0;
 778        let inlay_point = InlayPoint(cursor.start().1.0 + overshoot);
 779        let input_rows = self.inlay_snapshot.row_infos(inlay_point.row());
 780
 781        FoldRows {
 782            fold_point,
 783            input_rows,
 784            cursor,
 785        }
 786    }
 787
 788    pub fn max_point(&self) -> FoldPoint {
 789        FoldPoint(self.transforms.summary().output.lines)
 790    }
 791
 792    #[cfg(test)]
 793    pub fn longest_row(&self) -> u32 {
 794        self.transforms.summary().output.longest_row
 795    }
 796
 797    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Fold>
 798    where
 799        T: ToOffset,
 800    {
 801        let buffer = &self.inlay_snapshot.filter_snapshot.buffer_snapshot;
 802        let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 803        let mut folds = intersecting_folds(&self.inlay_snapshot, &self.folds, range, false);
 804        iter::from_fn(move || {
 805            let item = folds.item();
 806            folds.next();
 807            item
 808        })
 809    }
 810
 811    pub fn intersects_fold<T>(&self, offset: T) -> bool
 812    where
 813        T: ToOffset,
 814    {
 815        let buffer_offset = offset.to_offset(&self.inlay_snapshot.filter_snapshot.buffer_snapshot);
 816        let filter_offset = self
 817            .inlay_snapshot
 818            .filter_snapshot
 819            .to_filter_offset(buffer_offset);
 820        let inlay_offset = self.inlay_snapshot.to_inlay_offset(filter_offset);
 821        let (_, _, item) = self
 822            .transforms
 823            .find::<InlayOffset, _>((), &inlay_offset, Bias::Right);
 824        item.is_some_and(|t| t.placeholder.is_some())
 825    }
 826
 827    pub fn is_line_folded(&self, buffer_row: MultiBufferRow) -> bool {
 828        let filter_point = self
 829            .inlay_snapshot
 830            .filter_snapshot
 831            .to_filter_point(Point::new(buffer_row.0, 0));
 832        let mut inlay_point = self.inlay_snapshot.to_inlay_point(filter_point);
 833        let mut cursor = self.transforms.cursor::<InlayPoint>(());
 834        cursor.seek(&inlay_point, Bias::Right);
 835        loop {
 836            match cursor.item() {
 837                Some(transform) => {
 838                    let filter_point = self.inlay_snapshot.to_filter_point(inlay_point);
 839                    // FIXME unclear what bias to use here
 840                    let buffer_point = self
 841                        .inlay_snapshot
 842                        .filter_snapshot
 843                        .to_buffer_point(filter_point, Bias::Left);
 844                    if buffer_point.row != buffer_row.0 {
 845                        return false;
 846                    } else if transform.placeholder.is_some() {
 847                        return true;
 848                    }
 849                }
 850                None => return false,
 851            }
 852
 853            if cursor.end().row() == inlay_point.row() {
 854                cursor.next();
 855            } else {
 856                inlay_point.0 += Point::new(1, 0);
 857                cursor.seek(&inlay_point, Bias::Right);
 858            }
 859        }
 860    }
 861
 862    pub(crate) fn chunks<'a>(
 863        &'a self,
 864        range: Range<FoldOffset>,
 865        language_aware: bool,
 866        highlights: Highlights<'a>,
 867    ) -> FoldChunks<'a> {
 868        let mut transform_cursor = self
 869            .transforms
 870            .cursor::<Dimensions<FoldOffset, InlayOffset>>(());
 871        transform_cursor.seek(&range.start, Bias::Right);
 872
 873        let inlay_start = {
 874            let overshoot = range.start.0 - transform_cursor.start().0.0;
 875            transform_cursor.start().1 + InlayOffset(overshoot)
 876        };
 877
 878        let transform_end = transform_cursor.end();
 879
 880        let inlay_end = if transform_cursor
 881            .item()
 882            .is_none_or(|transform| transform.is_fold())
 883        {
 884            inlay_start
 885        } else if range.end < transform_end.0 {
 886            let overshoot = range.end.0 - transform_cursor.start().0.0;
 887            transform_cursor.start().1 + InlayOffset(overshoot)
 888        } else {
 889            transform_end.1
 890        };
 891
 892        FoldChunks {
 893            transform_cursor,
 894            inlay_chunks: self.inlay_snapshot.chunks(
 895                inlay_start..inlay_end,
 896                language_aware,
 897                highlights,
 898            ),
 899            inlay_chunk: None,
 900            inlay_offset: inlay_start,
 901            output_offset: range.start,
 902            max_output_offset: range.end,
 903        }
 904    }
 905
 906    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 907        self.chunks(
 908            start.to_offset(self)..self.len(),
 909            false,
 910            Highlights::default(),
 911        )
 912        .flat_map(|chunk| chunk.text.chars())
 913    }
 914
 915    pub fn chunks_at(&self, start: FoldPoint) -> FoldChunks<'_> {
 916        self.chunks(
 917            start.to_offset(self)..self.len(),
 918            false,
 919            Highlights::default(),
 920        )
 921    }
 922
 923    #[cfg(test)]
 924    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 925        if offset > self.len() {
 926            self.len()
 927        } else {
 928            self.clip_point(offset.to_point(self), bias).to_offset(self)
 929        }
 930    }
 931
 932    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 933        let (start, end, item) = self
 934            .transforms
 935            .find::<Dimensions<FoldPoint, InlayPoint>, _>((), &point, Bias::Right);
 936        if let Some(transform) = item {
 937            let transform_start = start.0.0;
 938            if transform.placeholder.is_some() {
 939                if point.0 == transform_start || matches!(bias, Bias::Left) {
 940                    FoldPoint(transform_start)
 941                } else {
 942                    FoldPoint(end.0.0)
 943                }
 944            } else {
 945                let overshoot = InlayPoint(point.0 - transform_start);
 946                let inlay_point = start.1 + overshoot;
 947                let clipped_inlay_point = self.inlay_snapshot.clip_point(inlay_point, bias);
 948                FoldPoint(start.0.0 + (clipped_inlay_point - start.1).0)
 949            }
 950        } else {
 951            FoldPoint(self.transforms.summary().output.lines)
 952        }
 953    }
 954}
 955
 956fn push_isomorphic(transforms: &mut SumTree<Transform>, summary: TextSummary) {
 957    let mut did_merge = false;
 958    transforms.update_last(
 959        |last| {
 960            if !last.is_fold() {
 961                last.summary.input += summary;
 962                last.summary.output += summary;
 963                did_merge = true;
 964            }
 965        },
 966        (),
 967    );
 968    if !did_merge {
 969        transforms.push(
 970            Transform {
 971                summary: TransformSummary {
 972                    input: summary,
 973                    output: summary,
 974                },
 975                placeholder: None,
 976            },
 977            (),
 978        )
 979    }
 980}
 981
 982fn intersecting_folds<'a>(
 983    inlay_snapshot: &'a InlaySnapshot,
 984    folds: &'a SumTree<Fold>,
 985    range: Range<usize>,
 986    inclusive: bool,
 987) -> FilterCursor<'a, 'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize> {
 988    let buffer = &inlay_snapshot.filter_snapshot.buffer_snapshot;
 989    let start = buffer.anchor_before(range.start.to_offset(buffer));
 990    let end = buffer.anchor_after(range.end.to_offset(buffer));
 991    let mut cursor = folds.filter::<_, usize>(buffer, move |summary| {
 992        let start_cmp = start.cmp(&summary.max_end, buffer);
 993        let end_cmp = end.cmp(&summary.min_start, buffer);
 994
 995        if inclusive {
 996            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 997        } else {
 998            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 999        }
1000    });
1001    cursor.next();
1002    cursor
1003}
1004
1005fn consolidate_inlay_edits(mut edits: Vec<InlayEdit>) -> Vec<InlayEdit> {
1006    edits.sort_unstable_by(|a, b| {
1007        a.old
1008            .start
1009            .cmp(&b.old.start)
1010            .then_with(|| b.old.end.cmp(&a.old.end))
1011    });
1012
1013    let _old_alloc_ptr = edits.as_ptr();
1014    let mut inlay_edits = edits.into_iter();
1015
1016    if let Some(mut first_edit) = inlay_edits.next() {
1017        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
1018        #[allow(clippy::filter_map_identity)]
1019        let mut v: Vec<_> = inlay_edits
1020            .scan(&mut first_edit, |prev_edit, edit| {
1021                if prev_edit.old.end >= edit.old.start {
1022                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
1023                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
1024                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
1025                    Some(None) // Skip this edit, it's merged
1026                } else {
1027                    let prev = std::mem::replace(*prev_edit, edit);
1028                    Some(Some(prev)) // Yield the previous edit
1029                }
1030            })
1031            .filter_map(|x| x)
1032            .collect();
1033        v.push(first_edit.clone());
1034        debug_assert_eq!(_old_alloc_ptr, v.as_ptr(), "Inlay edits were reallocated");
1035        v
1036    } else {
1037        vec![]
1038    }
1039}
1040
1041fn consolidate_fold_edits(mut edits: Vec<FoldEdit>) -> Vec<FoldEdit> {
1042    edits.sort_unstable_by(|a, b| {
1043        a.old
1044            .start
1045            .cmp(&b.old.start)
1046            .then_with(|| b.old.end.cmp(&a.old.end))
1047    });
1048    let _old_alloc_ptr = edits.as_ptr();
1049    let mut fold_edits = edits.into_iter();
1050
1051    if let Some(mut first_edit) = fold_edits.next() {
1052        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
1053        #[allow(clippy::filter_map_identity)]
1054        let mut v: Vec<_> = fold_edits
1055            .scan(&mut first_edit, |prev_edit, edit| {
1056                if prev_edit.old.end >= edit.old.start {
1057                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
1058                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
1059                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
1060                    Some(None) // Skip this edit, it's merged
1061                } else {
1062                    let prev = std::mem::replace(*prev_edit, edit);
1063                    Some(Some(prev)) // Yield the previous edit
1064                }
1065            })
1066            .filter_map(|x| x)
1067            .collect();
1068        v.push(first_edit.clone());
1069        v
1070    } else {
1071        vec![]
1072    }
1073}
1074
1075#[derive(Clone, Debug, Default)]
1076struct Transform {
1077    summary: TransformSummary,
1078    placeholder: Option<TransformPlaceholder>,
1079}
1080
1081#[derive(Clone, Debug)]
1082struct TransformPlaceholder {
1083    text: &'static str,
1084    chars: u128,
1085    renderer: ChunkRenderer,
1086}
1087
1088impl Transform {
1089    fn is_fold(&self) -> bool {
1090        self.placeholder.is_some()
1091    }
1092}
1093
1094#[derive(Clone, Debug, Default, Eq, PartialEq)]
1095struct TransformSummary {
1096    output: TextSummary,
1097    input: TextSummary,
1098}
1099
1100impl sum_tree::Item for Transform {
1101    type Summary = TransformSummary;
1102
1103    fn summary(&self, _cx: ()) -> Self::Summary {
1104        self.summary.clone()
1105    }
1106}
1107
1108impl sum_tree::ContextLessSummary for TransformSummary {
1109    fn zero() -> Self {
1110        Default::default()
1111    }
1112
1113    fn add_summary(&mut self, other: &Self) {
1114        self.input += &other.input;
1115        self.output += &other.output;
1116    }
1117}
1118
1119#[derive(Copy, Clone, Eq, PartialEq, Debug, Default, Ord, PartialOrd, Hash)]
1120pub struct FoldId(pub(super) usize);
1121
1122impl From<FoldId> for ElementId {
1123    fn from(val: FoldId) -> Self {
1124        val.0.into()
1125    }
1126}
1127
1128#[derive(Clone, Debug, Eq, PartialEq)]
1129pub struct Fold {
1130    pub id: FoldId,
1131    pub range: FoldRange,
1132    pub placeholder: FoldPlaceholder,
1133}
1134
1135#[derive(Clone, Debug, Eq, PartialEq)]
1136pub struct FoldRange(Range<Anchor>);
1137
1138impl Deref for FoldRange {
1139    type Target = Range<Anchor>;
1140
1141    fn deref(&self) -> &Self::Target {
1142        &self.0
1143    }
1144}
1145
1146impl DerefMut for FoldRange {
1147    fn deref_mut(&mut self) -> &mut Self::Target {
1148        &mut self.0
1149    }
1150}
1151
1152impl Default for FoldRange {
1153    fn default() -> Self {
1154        Self(Anchor::min()..Anchor::max())
1155    }
1156}
1157
1158#[derive(Clone, Debug)]
1159struct FoldMetadata {
1160    range: FoldRange,
1161    width: Option<Pixels>,
1162}
1163
1164impl sum_tree::Item for Fold {
1165    type Summary = FoldSummary;
1166
1167    fn summary(&self, _cx: &MultiBufferSnapshot) -> Self::Summary {
1168        FoldSummary {
1169            start: self.range.start,
1170            end: self.range.end,
1171            min_start: self.range.start,
1172            max_end: self.range.end,
1173            count: 1,
1174        }
1175    }
1176}
1177
1178#[derive(Clone, Debug)]
1179pub struct FoldSummary {
1180    start: Anchor,
1181    end: Anchor,
1182    min_start: Anchor,
1183    max_end: Anchor,
1184    count: usize,
1185}
1186
1187impl Default for FoldSummary {
1188    fn default() -> Self {
1189        Self {
1190            start: Anchor::min(),
1191            end: Anchor::max(),
1192            min_start: Anchor::max(),
1193            max_end: Anchor::min(),
1194            count: 0,
1195        }
1196    }
1197}
1198
1199impl sum_tree::Summary for FoldSummary {
1200    type Context<'a> = &'a MultiBufferSnapshot;
1201
1202    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1203        Default::default()
1204    }
1205
1206    fn add_summary(&mut self, other: &Self, buffer: Self::Context<'_>) {
1207        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
1208            self.min_start = other.min_start;
1209        }
1210        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
1211            self.max_end = other.max_end;
1212        }
1213
1214        #[cfg(debug_assertions)]
1215        {
1216            let start_comparison = self.start.cmp(&other.start, buffer);
1217            assert!(start_comparison <= Ordering::Equal);
1218            if start_comparison == Ordering::Equal {
1219                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
1220            }
1221        }
1222
1223        self.start = other.start;
1224        self.end = other.end;
1225        self.count += other.count;
1226    }
1227}
1228
1229impl<'a> sum_tree::Dimension<'a, FoldSummary> for FoldRange {
1230    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1231        Default::default()
1232    }
1233
1234    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1235        self.0.start = summary.start;
1236        self.0.end = summary.end;
1237    }
1238}
1239
1240impl sum_tree::SeekTarget<'_, FoldSummary, FoldRange> for FoldRange {
1241    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
1242        AnchorRangeExt::cmp(&self.0, &other.0, buffer)
1243    }
1244}
1245
1246impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
1247    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1248        Default::default()
1249    }
1250
1251    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1252        *self += summary.count;
1253    }
1254}
1255
1256#[derive(Clone)]
1257pub struct FoldRows<'a> {
1258    cursor: Cursor<'a, 'static, Transform, Dimensions<FoldPoint, InlayPoint>>,
1259    input_rows: InlayBufferRows<'a>,
1260    fold_point: FoldPoint,
1261}
1262
1263impl FoldRows<'_> {
1264    pub(crate) fn seek(&mut self, row: u32) {
1265        let fold_point = FoldPoint::new(row, 0);
1266        self.cursor.seek(&fold_point, Bias::Left);
1267        let overshoot = fold_point.0 - self.cursor.start().0.0;
1268        let inlay_point = InlayPoint(self.cursor.start().1.0 + overshoot);
1269        self.input_rows.seek(inlay_point.row());
1270        self.fold_point = fold_point;
1271    }
1272}
1273
1274impl Iterator for FoldRows<'_> {
1275    type Item = RowInfo;
1276
1277    fn next(&mut self) -> Option<Self::Item> {
1278        let mut traversed_fold = false;
1279        while self.fold_point > self.cursor.end().0 {
1280            self.cursor.next();
1281            traversed_fold = true;
1282            if self.cursor.item().is_none() {
1283                break;
1284            }
1285        }
1286
1287        if self.cursor.item().is_some() {
1288            if traversed_fold {
1289                self.input_rows.seek(self.cursor.start().1.0.row);
1290                self.input_rows.next();
1291            }
1292            *self.fold_point.row_mut() += 1;
1293            self.input_rows.next()
1294        } else {
1295            None
1296        }
1297    }
1298}
1299
1300/// A chunk of a buffer's text, along with its syntax highlight and
1301/// diagnostic status.
1302#[derive(Clone, Debug, Default)]
1303pub struct Chunk<'a> {
1304    /// The text of the chunk.
1305    pub text: &'a str,
1306    /// The syntax highlighting style of the chunk.
1307    pub syntax_highlight_id: Option<HighlightId>,
1308    /// The highlight style that has been applied to this chunk in
1309    /// the editor.
1310    pub highlight_style: Option<HighlightStyle>,
1311    /// The severity of diagnostic associated with this chunk, if any.
1312    pub diagnostic_severity: Option<lsp::DiagnosticSeverity>,
1313    /// Whether this chunk of text is marked as unnecessary.
1314    pub is_unnecessary: bool,
1315    /// Whether this chunk of text should be underlined.
1316    pub underline: bool,
1317    /// Whether this chunk of text was originally a tab character.
1318    pub is_tab: bool,
1319    /// Whether this chunk of text was originally a tab character.
1320    pub is_inlay: bool,
1321    /// An optional recipe for how the chunk should be presented.
1322    pub renderer: Option<ChunkRenderer>,
1323    /// Bitmap of tab character locations in chunk
1324    pub tabs: u128,
1325    /// Bitmap of character locations in chunk
1326    pub chars: u128,
1327}
1328
1329#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
1330pub enum ChunkRendererId {
1331    Fold(FoldId),
1332    Inlay(InlayId),
1333}
1334
1335/// A recipe for how the chunk should be presented.
1336#[derive(Clone)]
1337pub struct ChunkRenderer {
1338    /// The id of the renderer associated with this chunk.
1339    pub id: ChunkRendererId,
1340    /// Creates a custom element to represent this chunk.
1341    pub render: Arc<dyn Send + Sync + Fn(&mut ChunkRendererContext) -> AnyElement>,
1342    /// If true, the element is constrained to the shaped width of the text.
1343    pub constrain_width: bool,
1344    /// The width of the element, as measured during the last layout pass.
1345    ///
1346    /// This is None if the element has not been laid out yet.
1347    pub measured_width: Option<Pixels>,
1348}
1349
1350pub struct ChunkRendererContext<'a, 'b> {
1351    pub window: &'a mut Window,
1352    pub context: &'b mut App,
1353    pub max_width: Pixels,
1354}
1355
1356impl fmt::Debug for ChunkRenderer {
1357    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1358        f.debug_struct("ChunkRenderer")
1359            .field("constrain_width", &self.constrain_width)
1360            .finish()
1361    }
1362}
1363
1364impl Deref for ChunkRendererContext<'_, '_> {
1365    type Target = App;
1366
1367    fn deref(&self) -> &Self::Target {
1368        self.context
1369    }
1370}
1371
1372impl DerefMut for ChunkRendererContext<'_, '_> {
1373    fn deref_mut(&mut self) -> &mut Self::Target {
1374        self.context
1375    }
1376}
1377
1378pub struct FoldChunks<'a> {
1379    transform_cursor: Cursor<'a, 'static, Transform, Dimensions<FoldOffset, InlayOffset>>,
1380    inlay_chunks: InlayChunks<'a>,
1381    inlay_chunk: Option<(InlayOffset, InlayChunk<'a>)>,
1382    inlay_offset: InlayOffset,
1383    output_offset: FoldOffset,
1384    max_output_offset: FoldOffset,
1385}
1386
1387impl FoldChunks<'_> {
1388    pub(crate) fn seek(&mut self, range: Range<FoldOffset>) {
1389        self.transform_cursor.seek(&range.start, Bias::Right);
1390
1391        let inlay_start = {
1392            let overshoot = range.start.0 - self.transform_cursor.start().0.0;
1393            self.transform_cursor.start().1 + InlayOffset(overshoot)
1394        };
1395
1396        let transform_end = self.transform_cursor.end();
1397
1398        let inlay_end = if self
1399            .transform_cursor
1400            .item()
1401            .is_none_or(|transform| transform.is_fold())
1402        {
1403            inlay_start
1404        } else if range.end < transform_end.0 {
1405            let overshoot = range.end.0 - self.transform_cursor.start().0.0;
1406            self.transform_cursor.start().1 + InlayOffset(overshoot)
1407        } else {
1408            transform_end.1
1409        };
1410
1411        self.inlay_chunks.seek(inlay_start..inlay_end);
1412        self.inlay_chunk = None;
1413        self.inlay_offset = inlay_start;
1414        self.output_offset = range.start;
1415        self.max_output_offset = range.end;
1416    }
1417}
1418
1419impl<'a> Iterator for FoldChunks<'a> {
1420    type Item = Chunk<'a>;
1421
1422    fn next(&mut self) -> Option<Self::Item> {
1423        if self.output_offset >= self.max_output_offset {
1424            return None;
1425        }
1426
1427        let transform = self.transform_cursor.item()?;
1428
1429        // If we're in a fold, then return the fold's display text and
1430        // advance the transform and buffer cursors to the end of the fold.
1431        if let Some(placeholder) = transform.placeholder.as_ref() {
1432            self.inlay_chunk.take();
1433            self.inlay_offset += InlayOffset(transform.summary.input.len);
1434
1435            while self.inlay_offset >= self.transform_cursor.end().1
1436                && self.transform_cursor.item().is_some()
1437            {
1438                self.transform_cursor.next();
1439            }
1440
1441            self.output_offset.0 += placeholder.text.len();
1442            return Some(Chunk {
1443                text: placeholder.text,
1444                chars: placeholder.chars,
1445                renderer: Some(placeholder.renderer.clone()),
1446                ..Default::default()
1447            });
1448        }
1449
1450        // When we reach a non-fold region, seek the underlying text
1451        // chunk iterator to the next unfolded range.
1452        if self.inlay_offset == self.transform_cursor.start().1
1453            && self.inlay_chunks.offset() != self.inlay_offset
1454        {
1455            let transform_start = self.transform_cursor.start();
1456            let transform_end = self.transform_cursor.end();
1457            let inlay_end = if self.max_output_offset < transform_end.0 {
1458                let overshoot = self.max_output_offset.0 - transform_start.0.0;
1459                transform_start.1 + InlayOffset(overshoot)
1460            } else {
1461                transform_end.1
1462            };
1463
1464            self.inlay_chunks.seek(self.inlay_offset..inlay_end);
1465        }
1466
1467        // Retrieve a chunk from the current location in the buffer.
1468        if self.inlay_chunk.is_none() {
1469            let chunk_offset = self.inlay_chunks.offset();
1470            self.inlay_chunk = self.inlay_chunks.next().map(|chunk| (chunk_offset, chunk));
1471        }
1472
1473        // Otherwise, take a chunk from the buffer's text.
1474        if let Some((buffer_chunk_start, mut inlay_chunk)) = self.inlay_chunk.clone() {
1475            let chunk = &mut inlay_chunk.chunk;
1476            let buffer_chunk_end = buffer_chunk_start + InlayOffset(chunk.text.len());
1477            let transform_end = self.transform_cursor.end().1;
1478            let chunk_end = buffer_chunk_end.min(transform_end);
1479
1480            let bit_start = (self.inlay_offset - buffer_chunk_start).0;
1481            let bit_end = (chunk_end - buffer_chunk_start).0;
1482            chunk.text = &chunk.text[bit_start..bit_end];
1483
1484            let bit_end = (chunk_end - buffer_chunk_start).0;
1485            let mask = 1u128.unbounded_shl(bit_end as u32).wrapping_sub(1);
1486
1487            chunk.tabs = (chunk.tabs >> bit_start) & mask;
1488            chunk.chars = (chunk.chars >> bit_start) & mask;
1489
1490            if chunk_end == transform_end {
1491                self.transform_cursor.next();
1492            } else if chunk_end == buffer_chunk_end {
1493                self.inlay_chunk.take();
1494            }
1495
1496            self.inlay_offset = chunk_end;
1497            self.output_offset.0 += chunk.text.len();
1498            return Some(Chunk {
1499                text: chunk.text,
1500                tabs: chunk.tabs,
1501                chars: chunk.chars,
1502                syntax_highlight_id: chunk.syntax_highlight_id,
1503                highlight_style: chunk.highlight_style,
1504                diagnostic_severity: chunk.diagnostic_severity,
1505                is_unnecessary: chunk.is_unnecessary,
1506                is_tab: chunk.is_tab,
1507                is_inlay: chunk.is_inlay,
1508                underline: chunk.underline,
1509                renderer: inlay_chunk.renderer,
1510            });
1511        }
1512
1513        None
1514    }
1515}
1516
1517#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1518pub struct FoldOffset(pub usize);
1519
1520impl FoldOffset {
1521    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1522        let (start, _, item) = snapshot
1523            .transforms
1524            .find::<Dimensions<FoldOffset, TransformSummary>, _>((), &self, Bias::Right);
1525        let overshoot = if item.is_none_or(|t| t.is_fold()) {
1526            Point::new(0, (self.0 - start.0.0) as u32)
1527        } else {
1528            let inlay_offset = start.1.input.len + self.0 - start.0.0;
1529            let inlay_point = snapshot.inlay_snapshot.to_point(InlayOffset(inlay_offset));
1530            inlay_point.0 - start.1.input.lines
1531        };
1532        FoldPoint(start.1.output.lines + overshoot)
1533    }
1534
1535    #[cfg(test)]
1536    pub fn to_inlay_offset(self, snapshot: &FoldSnapshot) -> InlayOffset {
1537        let (start, _, _) = snapshot
1538            .transforms
1539            .find::<Dimensions<FoldOffset, InlayOffset>, _>((), &self, Bias::Right);
1540        let overshoot = self.0 - start.0.0;
1541        InlayOffset(start.1.0 + overshoot)
1542    }
1543}
1544
1545impl Add for FoldOffset {
1546    type Output = Self;
1547
1548    fn add(self, rhs: Self) -> Self::Output {
1549        Self(self.0 + rhs.0)
1550    }
1551}
1552
1553impl AddAssign for FoldOffset {
1554    fn add_assign(&mut self, rhs: Self) {
1555        self.0 += rhs.0;
1556    }
1557}
1558
1559impl Sub for FoldOffset {
1560    type Output = Self;
1561
1562    fn sub(self, rhs: Self) -> Self::Output {
1563        Self(self.0 - rhs.0)
1564    }
1565}
1566
1567impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1568    fn zero(_cx: ()) -> Self {
1569        Default::default()
1570    }
1571
1572    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1573        self.0 += &summary.output.len;
1574    }
1575}
1576
1577impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayPoint {
1578    fn zero(_cx: ()) -> Self {
1579        Default::default()
1580    }
1581
1582    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1583        self.0 += &summary.input.lines;
1584    }
1585}
1586
1587impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayOffset {
1588    fn zero(_cx: ()) -> Self {
1589        Default::default()
1590    }
1591
1592    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1593        self.0 += &summary.input.len;
1594    }
1595}
1596
1597pub type FoldEdit = Edit<FoldOffset>;
1598
1599#[cfg(test)]
1600mod tests {
1601    use super::*;
1602    use crate::display_map::filter_map::FilterMap;
1603    use crate::{MultiBuffer, ToPoint, display_map::inlay_map::InlayMap};
1604    use Bias::{Left, Right};
1605    use collections::HashSet;
1606    use rand::prelude::*;
1607    use settings::SettingsStore;
1608    use std::{env, mem};
1609    use text::Patch;
1610    use util::RandomCharIter;
1611    use util::test::sample_text;
1612
1613    #[gpui::test]
1614    fn test_basic_folds(cx: &mut gpui::App) {
1615        init_test(cx);
1616        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1617        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1618        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1619        let (mut filter_map, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
1620        let (mut inlay_map, inlay_snapshot) = InlayMap::new(filter_snapshot);
1621        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1622
1623        let (mut writer, _, _) = map.write(inlay_snapshot, vec![]);
1624        let (snapshot2, edits) = writer.fold(vec![
1625            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1626            (Point::new(2, 4)..Point::new(4, 1), FoldPlaceholder::test()),
1627        ]);
1628        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1629        assert_eq!(
1630            edits,
1631            &[
1632                FoldEdit {
1633                    old: FoldOffset(2)..FoldOffset(16),
1634                    new: FoldOffset(2)..FoldOffset(5),
1635                },
1636                FoldEdit {
1637                    old: FoldOffset(18)..FoldOffset(29),
1638                    new: FoldOffset(7)..FoldOffset(10)
1639                },
1640            ]
1641        );
1642
1643        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1644            buffer.edit(
1645                vec![
1646                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1647                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1648                ],
1649                None,
1650                cx,
1651            );
1652            buffer.snapshot(cx)
1653        });
1654
1655        let (filter_snapshot, filter_edits) =
1656            filter_map.sync(buffer_snapshot, subscription.consume().into_inner());
1657        let (inlay_snapshot, inlay_edits) = inlay_map.sync(filter_snapshot, filter_edits);
1658        let (snapshot3, edits) = map.read(inlay_snapshot, inlay_edits);
1659        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1660        assert_eq!(
1661            edits,
1662            &[
1663                FoldEdit {
1664                    old: FoldOffset(0)..FoldOffset(1),
1665                    new: FoldOffset(0)..FoldOffset(3),
1666                },
1667                FoldEdit {
1668                    old: FoldOffset(6)..FoldOffset(6),
1669                    new: FoldOffset(8)..FoldOffset(11),
1670                },
1671            ]
1672        );
1673
1674        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1675            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1676            buffer.snapshot(cx)
1677        });
1678        let (filter_snapshot, filter_edits) =
1679            filter_map.sync(buffer_snapshot, subscription.consume().into_inner());
1680        let (inlay_snapshot, inlay_edits) = inlay_map.sync(filter_snapshot, filter_edits);
1681        let (snapshot4, _) = map.read(inlay_snapshot.clone(), inlay_edits);
1682        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1683
1684        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1685        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1686        let (snapshot5, _) = map.read(inlay_snapshot.clone(), vec![]);
1687        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1688
1689        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1690        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1691        let (snapshot6, _) = map.read(inlay_snapshot, vec![]);
1692        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1693    }
1694
1695    #[gpui::test]
1696    fn test_adjacent_folds(cx: &mut gpui::App) {
1697        init_test(cx);
1698        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1699        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1700        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1701        let (mut filter_map, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
1702        let (mut inlay_map, inlay_snapshot) = InlayMap::new(filter_snapshot);
1703
1704        {
1705            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1706
1707            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1708            writer.fold(vec![(5..8, FoldPlaceholder::test())]);
1709            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1710            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1711
1712            // Create an fold adjacent to the start of the first fold.
1713            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1714            writer.fold(vec![
1715                (0..1, FoldPlaceholder::test()),
1716                (2..5, FoldPlaceholder::test()),
1717            ]);
1718            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1719            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1720
1721            // Create an fold adjacent to the end of the first fold.
1722            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1723            writer.fold(vec![
1724                (11..11, FoldPlaceholder::test()),
1725                (8..10, FoldPlaceholder::test()),
1726            ]);
1727            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1728            assert_eq!(snapshot.text(), "⋯b⋯kl");
1729        }
1730
1731        {
1732            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1733
1734            // Create two adjacent folds.
1735            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1736            writer.fold(vec![
1737                (0..2, FoldPlaceholder::test()),
1738                (2..5, FoldPlaceholder::test()),
1739            ]);
1740            let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1741            assert_eq!(snapshot.text(), "⋯fghijkl");
1742
1743            // Edit within one of the folds.
1744            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1745                buffer.edit([(0..1, "12345")], None, cx);
1746                buffer.snapshot(cx)
1747            });
1748            let (filter_snapshot, filter_edits) =
1749                filter_map.sync(buffer_snapshot, subscription.consume().into_inner());
1750            let (inlay_snapshot, inlay_edits) = inlay_map.sync(filter_snapshot, filter_edits);
1751            let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1752            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1753        }
1754    }
1755
1756    #[gpui::test]
1757    fn test_overlapping_folds(cx: &mut gpui::App) {
1758        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1759        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1760        let (_, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
1761        let (_, inlay_snapshot) = InlayMap::new(filter_snapshot);
1762        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1763        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1764        writer.fold(vec![
1765            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1766            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1767            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1768            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1769        ]);
1770        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1771        assert_eq!(snapshot.text(), "aa⋯eeeee");
1772    }
1773
1774    #[gpui::test]
1775    fn test_merging_folds_via_edit(cx: &mut gpui::App) {
1776        init_test(cx);
1777        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1778        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1779        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1780        let (mut filter_map, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
1781        let (mut inlay_map, inlay_snapshot) = InlayMap::new(filter_snapshot);
1782        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1783
1784        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1785        writer.fold(vec![
1786            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1787            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1788        ]);
1789        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1790        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1791
1792        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1793            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1794            buffer.snapshot(cx)
1795        });
1796        let (filter_snapshot, filter_edits) =
1797            filter_map.sync(buffer_snapshot, subscription.consume().into_inner());
1798        let (inlay_snapshot, inlay_edits) = inlay_map.sync(filter_snapshot, filter_edits);
1799        let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1800        assert_eq!(snapshot.text(), "aa⋯eeeee");
1801    }
1802
1803    #[gpui::test]
1804    fn test_folds_in_range(cx: &mut gpui::App) {
1805        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1806        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1807        let (_, filter_snapshot) = FilterMap::new(None, buffer_snapshot.clone());
1808        let (_, inlay_snapshot) = InlayMap::new(filter_snapshot);
1809        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1810
1811        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1812        writer.fold(vec![
1813            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1814            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1815            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1816            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1817        ]);
1818        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1819        let fold_ranges = snapshot
1820            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1821            .map(|fold| {
1822                fold.range.start.to_point(&buffer_snapshot)
1823                    ..fold.range.end.to_point(&buffer_snapshot)
1824            })
1825            .collect::<Vec<_>>();
1826        assert_eq!(
1827            fold_ranges,
1828            vec![
1829                Point::new(0, 2)..Point::new(2, 2),
1830                Point::new(1, 2)..Point::new(3, 2)
1831            ]
1832        );
1833    }
1834
1835    #[gpui::test(iterations = 100)]
1836    fn test_random_folds(cx: &mut gpui::App, mut rng: StdRng) {
1837        init_test(cx);
1838        let operations = env::var("OPERATIONS")
1839            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1840            .unwrap_or(10);
1841
1842        let len = rng.random_range(0..10);
1843        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1844        let buffer = if rng.random() {
1845            MultiBuffer::build_simple(&text, cx)
1846        } else {
1847            MultiBuffer::build_random(&mut rng, cx)
1848        };
1849        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1850        let (mut filter_map, filter_snapshot) = FilterMap::new(None, buffer_snapshot.clone());
1851        let (mut inlay_map, inlay_snapshot) = InlayMap::new(filter_snapshot);
1852        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1853
1854        let (mut initial_snapshot, _) = map.read(inlay_snapshot, vec![]);
1855        let mut snapshot_edits = Vec::new();
1856
1857        let mut next_inlay_id = 0;
1858        for _ in 0..operations {
1859            log::info!("text: {:?}", buffer_snapshot.text());
1860            let mut buffer_edits = Vec::new();
1861            let mut inlay_edits = Vec::new();
1862            match rng.random_range(0..=100) {
1863                0..=39 => {
1864                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1865                }
1866                40..=59 => {
1867                    let (_, edits) = inlay_map.randomly_mutate(&mut next_inlay_id, &mut rng);
1868                    inlay_edits = edits;
1869                }
1870                _ => buffer.update(cx, |buffer, cx| {
1871                    let subscription = buffer.subscribe();
1872                    let edit_count = rng.random_range(1..=5);
1873                    buffer.randomly_mutate(&mut rng, edit_count, cx);
1874                    buffer_snapshot = buffer.snapshot(cx);
1875                    let edits = subscription.consume().into_inner();
1876                    log::info!("editing {:?}", edits);
1877                    buffer_edits.extend(edits);
1878                }),
1879            };
1880
1881            let (filter_snapshot, filter_edits) =
1882                filter_map.sync(buffer_snapshot.clone(), buffer_edits);
1883            let (inlay_snapshot, new_inlay_edits) =
1884                inlay_map.sync(filter_snapshot.clone(), filter_edits);
1885            log::info!("inlay text {:?}", inlay_snapshot.text());
1886
1887            let inlay_edits = Patch::new(inlay_edits)
1888                .compose(new_inlay_edits)
1889                .into_inner();
1890            let (snapshot, edits) = map.read(inlay_snapshot.clone(), inlay_edits);
1891            snapshot_edits.push((snapshot.clone(), edits));
1892
1893            let mut expected_text: String = inlay_snapshot.text().to_string();
1894            for fold_range in map.merged_folds().into_iter().rev() {
1895                let fold_filter_range = filter_snapshot.to_filter_offset(fold_range.start)
1896                    ..filter_snapshot.to_filter_offset(fold_range.end);
1897                let fold_inlay_range = inlay_snapshot.to_inlay_offset(fold_filter_range.start)
1898                    ..inlay_snapshot.to_inlay_offset(fold_filter_range.end);
1899                expected_text.replace_range(fold_inlay_range.start.0..fold_inlay_range.end.0, "");
1900            }
1901
1902            assert_eq!(snapshot.text(), expected_text);
1903            log::info!(
1904                "fold text {:?} ({} lines)",
1905                expected_text,
1906                expected_text.matches('\n').count() + 1
1907            );
1908
1909            let mut prev_row = 0;
1910            let mut expected_buffer_rows = Vec::new();
1911            for fold_range in map.merged_folds() {
1912                let fold_filter_range = filter_snapshot.to_filter_offset(fold_range.start)
1913                    ..filter_snapshot.to_filter_offset(fold_range.end);
1914                let fold_row_range = inlay_snapshot
1915                    .to_point(inlay_snapshot.to_inlay_offset(fold_filter_range.start))
1916                    .row()
1917                    ..inlay_snapshot
1918                        .to_point(inlay_snapshot.to_inlay_offset(fold_filter_range.end))
1919                        .row();
1920                expected_buffer_rows.extend(
1921                    inlay_snapshot
1922                        .row_infos(prev_row)
1923                        .take((1 + fold_row_range.start - prev_row) as usize),
1924                );
1925                prev_row = 1 + fold_row_range.end;
1926            }
1927            expected_buffer_rows.extend(inlay_snapshot.row_infos(prev_row));
1928
1929            assert_eq!(
1930                expected_buffer_rows.len(),
1931                expected_text.matches('\n').count() + 1,
1932                "wrong expected buffer rows {:?}. text: {:?}",
1933                expected_buffer_rows,
1934                expected_text
1935            );
1936
1937            for (output_row, line) in expected_text.lines().enumerate() {
1938                let line_len = snapshot.line_len(output_row as u32);
1939                assert_eq!(line_len, line.len() as u32);
1940            }
1941
1942            let longest_row = snapshot.longest_row();
1943            let longest_char_column = expected_text
1944                .split('\n')
1945                .nth(longest_row as usize)
1946                .unwrap()
1947                .chars()
1948                .count();
1949            let mut fold_point = FoldPoint::new(0, 0);
1950            let mut fold_offset = FoldOffset(0);
1951            let mut char_column = 0;
1952            for c in expected_text.chars() {
1953                let inlay_point = fold_point.to_inlay_point(&snapshot);
1954                let inlay_offset = fold_offset.to_inlay_offset(&snapshot);
1955                assert_eq!(
1956                    snapshot.to_fold_point(inlay_point, Right),
1957                    fold_point,
1958                    "{:?} -> fold point",
1959                    inlay_point,
1960                );
1961                assert_eq!(
1962                    inlay_snapshot.to_offset(inlay_point),
1963                    inlay_offset,
1964                    "inlay_snapshot.to_offset({:?})",
1965                    inlay_point,
1966                );
1967                assert_eq!(
1968                    fold_point.to_offset(&snapshot),
1969                    fold_offset,
1970                    "fold_point.to_offset({:?})",
1971                    fold_point,
1972                );
1973
1974                if c == '\n' {
1975                    *fold_point.row_mut() += 1;
1976                    *fold_point.column_mut() = 0;
1977                    char_column = 0;
1978                } else {
1979                    *fold_point.column_mut() += c.len_utf8() as u32;
1980                    char_column += 1;
1981                }
1982                fold_offset.0 += c.len_utf8();
1983                if char_column > longest_char_column {
1984                    panic!(
1985                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1986                        longest_row,
1987                        longest_char_column,
1988                        fold_point.row(),
1989                        char_column
1990                    );
1991                }
1992            }
1993
1994            for _ in 0..5 {
1995                let mut start = snapshot.clip_offset(
1996                    FoldOffset(rng.random_range(0..=snapshot.len().0)),
1997                    Bias::Left,
1998                );
1999                let mut end = snapshot.clip_offset(
2000                    FoldOffset(rng.random_range(0..=snapshot.len().0)),
2001                    Bias::Right,
2002                );
2003                if start > end {
2004                    mem::swap(&mut start, &mut end);
2005                }
2006
2007                let text = &expected_text[start.0..end.0];
2008                assert_eq!(
2009                    snapshot
2010                        .chunks(start..end, false, Highlights::default())
2011                        .map(|c| c.text)
2012                        .collect::<String>(),
2013                    text,
2014                );
2015            }
2016
2017            let mut fold_row = 0;
2018            while fold_row < expected_buffer_rows.len() as u32 {
2019                assert_eq!(
2020                    snapshot.row_infos(fold_row).collect::<Vec<_>>(),
2021                    expected_buffer_rows[(fold_row as usize)..],
2022                    "wrong buffer rows starting at fold row {}",
2023                    fold_row,
2024                );
2025                fold_row += 1;
2026            }
2027
2028            let folded_buffer_rows = map
2029                .merged_folds()
2030                .iter()
2031                .flat_map(|fold_range| {
2032                    let start_row = fold_range.start.to_point(&buffer_snapshot).row;
2033                    let end = fold_range.end.to_point(&buffer_snapshot);
2034                    if end.column == 0 {
2035                        start_row..end.row
2036                    } else {
2037                        start_row..end.row + 1
2038                    }
2039                })
2040                .collect::<HashSet<_>>();
2041            for row in 0..=buffer_snapshot.max_point().row {
2042                assert_eq!(
2043                    snapshot.is_line_folded(MultiBufferRow(row)),
2044                    folded_buffer_rows.contains(&row),
2045                    "expected buffer row {}{} to be folded",
2046                    row,
2047                    if folded_buffer_rows.contains(&row) {
2048                        ""
2049                    } else {
2050                        " not"
2051                    }
2052                );
2053            }
2054
2055            for _ in 0..5 {
2056                let end =
2057                    buffer_snapshot.clip_offset(rng.random_range(0..=buffer_snapshot.len()), Right);
2058                let start = buffer_snapshot.clip_offset(rng.random_range(0..=end), Left);
2059                let expected_folds = map
2060                    .snapshot
2061                    .folds
2062                    .items(&buffer_snapshot)
2063                    .into_iter()
2064                    .filter(|fold| {
2065                        let start = buffer_snapshot.anchor_before(start);
2066                        let end = buffer_snapshot.anchor_after(end);
2067                        start.cmp(&fold.range.end, &buffer_snapshot) == Ordering::Less
2068                            && end.cmp(&fold.range.start, &buffer_snapshot) == Ordering::Greater
2069                    })
2070                    .collect::<Vec<_>>();
2071
2072                assert_eq!(
2073                    snapshot
2074                        .folds_in_range(start..end)
2075                        .cloned()
2076                        .collect::<Vec<_>>(),
2077                    expected_folds
2078                );
2079            }
2080
2081            let text = snapshot.text();
2082            for _ in 0..5 {
2083                let start_row = rng.random_range(0..=snapshot.max_point().row());
2084                let start_column = rng.random_range(0..=snapshot.line_len(start_row));
2085                let end_row = rng.random_range(0..=snapshot.max_point().row());
2086                let end_column = rng.random_range(0..=snapshot.line_len(end_row));
2087                let mut start =
2088                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
2089                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
2090                if start > end {
2091                    mem::swap(&mut start, &mut end);
2092                }
2093
2094                let lines = start..end;
2095                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
2096                assert_eq!(
2097                    snapshot.text_summary_for_range(lines),
2098                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
2099                )
2100            }
2101
2102            let mut text = initial_snapshot.text();
2103            for (snapshot, edits) in snapshot_edits.drain(..) {
2104                let new_text = snapshot.text();
2105                for edit in edits {
2106                    let old_bytes = edit.new.start.0..edit.new.start.0 + edit.old_len().0;
2107                    let new_bytes = edit.new.start.0..edit.new.end.0;
2108                    text.replace_range(old_bytes, &new_text[new_bytes]);
2109                }
2110
2111                assert_eq!(text, new_text);
2112                initial_snapshot = snapshot;
2113            }
2114        }
2115    }
2116
2117    #[gpui::test]
2118    fn test_buffer_rows(cx: &mut gpui::App) {
2119        let text = sample_text(6, 6, 'a') + "\n";
2120        let buffer = MultiBuffer::build_simple(&text, cx);
2121
2122        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2123        let (_, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
2124        let (_, inlay_snapshot) = InlayMap::new(filter_snapshot);
2125        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
2126
2127        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
2128        writer.fold(vec![
2129            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
2130            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
2131        ]);
2132
2133        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
2134        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
2135        assert_eq!(
2136            snapshot
2137                .row_infos(0)
2138                .map(|info| info.buffer_row)
2139                .collect::<Vec<_>>(),
2140            [Some(0), Some(3), Some(5), Some(6)]
2141        );
2142        assert_eq!(
2143            snapshot
2144                .row_infos(3)
2145                .map(|info| info.buffer_row)
2146                .collect::<Vec<_>>(),
2147            [Some(6)]
2148        );
2149    }
2150
2151    #[gpui::test(iterations = 100)]
2152    fn test_random_chunk_bitmaps(cx: &mut gpui::App, mut rng: StdRng) {
2153        init_test(cx);
2154
2155        // Generate random buffer using existing test infrastructure
2156        let text_len = rng.random_range(0..10000);
2157        let buffer = if rng.random() {
2158            let text = RandomCharIter::new(&mut rng)
2159                .take(text_len)
2160                .collect::<String>();
2161            MultiBuffer::build_simple(&text, cx)
2162        } else {
2163            MultiBuffer::build_random(&mut rng, cx)
2164        };
2165        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2166        let (_, filter_snapshot) = FilterMap::new(None, buffer_snapshot);
2167        let (_, inlay_snapshot) = InlayMap::new(filter_snapshot);
2168        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
2169
2170        // Perform random mutations
2171        let mutation_count = rng.random_range(1..10);
2172        for _ in 0..mutation_count {
2173            fold_map.randomly_mutate(&mut rng);
2174        }
2175
2176        let (snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
2177
2178        // Get all chunks and verify their bitmaps
2179        let chunks = snapshot.chunks(
2180            FoldOffset(0)..FoldOffset(snapshot.len().0),
2181            false,
2182            Highlights::default(),
2183        );
2184
2185        for chunk in chunks {
2186            let chunk_text = chunk.text;
2187            let chars_bitmap = chunk.chars;
2188            let tabs_bitmap = chunk.tabs;
2189
2190            // Check empty chunks have empty bitmaps
2191            if chunk_text.is_empty() {
2192                assert_eq!(
2193                    chars_bitmap, 0,
2194                    "Empty chunk should have empty chars bitmap"
2195                );
2196                assert_eq!(tabs_bitmap, 0, "Empty chunk should have empty tabs bitmap");
2197                continue;
2198            }
2199
2200            // Verify that chunk text doesn't exceed 128 bytes
2201            assert!(
2202                chunk_text.len() <= 128,
2203                "Chunk text length {} exceeds 128 bytes",
2204                chunk_text.len()
2205            );
2206
2207            // Verify chars bitmap
2208            let char_indices = chunk_text
2209                .char_indices()
2210                .map(|(i, _)| i)
2211                .collect::<Vec<_>>();
2212
2213            for byte_idx in 0..chunk_text.len() {
2214                let should_have_bit = char_indices.contains(&byte_idx);
2215                let has_bit = chars_bitmap & (1 << byte_idx) != 0;
2216
2217                if has_bit != should_have_bit {
2218                    eprintln!("Chunk text bytes: {:?}", chunk_text.as_bytes());
2219                    eprintln!("Char indices: {:?}", char_indices);
2220                    eprintln!("Chars bitmap: {:#b}", chars_bitmap);
2221                    assert_eq!(
2222                        has_bit, should_have_bit,
2223                        "Chars bitmap mismatch at byte index {} in chunk {:?}. Expected bit: {}, Got bit: {}",
2224                        byte_idx, chunk_text, should_have_bit, has_bit
2225                    );
2226                }
2227            }
2228
2229            // Verify tabs bitmap
2230            for (byte_idx, byte) in chunk_text.bytes().enumerate() {
2231                let is_tab = byte == b'\t';
2232                let has_bit = tabs_bitmap & (1 << byte_idx) != 0;
2233
2234                assert_eq!(
2235                    has_bit, is_tab,
2236                    "Tabs bitmap mismatch at byte index {} in chunk {:?}. Byte: {:?}, Expected bit: {}, Got bit: {}",
2237                    byte_idx, chunk_text, byte as char, is_tab, has_bit
2238                );
2239            }
2240        }
2241    }
2242
2243    fn init_test(cx: &mut gpui::App) {
2244        let store = SettingsStore::test(cx);
2245        cx.set_global(store);
2246    }
2247
2248    impl FoldMap {
2249        fn merged_folds(&self) -> Vec<Range<usize>> {
2250            let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2251            let buffer = &inlay_snapshot.filter_snapshot.buffer_snapshot;
2252            let mut folds = self.snapshot.folds.items(buffer);
2253            // Ensure sorting doesn't change how folds get merged and displayed.
2254            folds.sort_by(|a, b| a.range.cmp(&b.range, buffer));
2255            let mut folds = folds
2256                .iter()
2257                .map(|fold| fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer))
2258                .peekable();
2259
2260            let mut merged_folds = Vec::new();
2261            while let Some(mut fold_range) = folds.next() {
2262                while let Some(next_range) = folds.peek() {
2263                    if fold_range.end >= next_range.start {
2264                        if next_range.end > fold_range.end {
2265                            fold_range.end = next_range.end;
2266                        }
2267                        folds.next();
2268                    } else {
2269                        break;
2270                    }
2271                }
2272                if fold_range.end > fold_range.start {
2273                    merged_folds.push(fold_range);
2274                }
2275            }
2276            merged_folds
2277        }
2278
2279        pub fn randomly_mutate(
2280            &mut self,
2281            rng: &mut impl Rng,
2282        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
2283            let mut snapshot_edits = Vec::new();
2284            match rng.random_range(0..=100) {
2285                0..=39 if !self.snapshot.folds.is_empty() => {
2286                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2287                    let buffer = &inlay_snapshot.filter_snapshot.buffer_snapshot;
2288                    let mut to_unfold = Vec::new();
2289                    for _ in 0..rng.random_range(1..=3) {
2290                        let end = buffer.clip_offset(rng.random_range(0..=buffer.len()), Right);
2291                        let start = buffer.clip_offset(rng.random_range(0..=end), Left);
2292                        to_unfold.push(start..end);
2293                    }
2294                    let inclusive = rng.random();
2295                    log::info!("unfolding {:?} (inclusive: {})", to_unfold, inclusive);
2296                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2297                    snapshot_edits.push((snapshot, edits));
2298                    let (snapshot, edits) = writer.unfold_intersecting(to_unfold, inclusive);
2299                    snapshot_edits.push((snapshot, edits));
2300                }
2301                _ => {
2302                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2303                    let buffer = &inlay_snapshot.filter_snapshot.buffer_snapshot;
2304                    let mut to_fold = Vec::new();
2305                    for _ in 0..rng.random_range(1..=2) {
2306                        let end = buffer.clip_offset(rng.random_range(0..=buffer.len()), Right);
2307                        let start = buffer.clip_offset(rng.random_range(0..=end), Left);
2308                        to_fold.push((start..end, FoldPlaceholder::test()));
2309                    }
2310                    log::info!("folding {:?}", to_fold);
2311                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2312                    snapshot_edits.push((snapshot, edits));
2313                    let (snapshot, edits) = writer.fold(to_fold);
2314                    snapshot_edits.push((snapshot, edits));
2315                }
2316            }
2317            snapshot_edits
2318        }
2319    }
2320}