fold_map.rs

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