fold_map.rs

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