fold_map.rs

   1use crate::display_map::inlay_map::InlayChunk;
   2
   3use super::{
   4    Highlights,
   5    inlay_map::{InlayBufferRows, InlayChunks, InlayEdit, InlayOffset, InlayPoint, InlaySnapshot},
   6};
   7use gpui::{AnyElement, App, ElementId, HighlightStyle, Pixels, SharedString, Stateful, Window};
   8use language::{Edit, HighlightId, Point};
   9use multi_buffer::{
  10    Anchor, AnchorRangeExt, MBTextSummary, MultiBufferOffset, MultiBufferRow, MultiBufferSnapshot,
  11    RowInfo, ToOffset,
  12};
  13use project::InlayId;
  14use std::{
  15    any::TypeId,
  16    cmp::{self, Ordering},
  17    fmt, iter,
  18    ops::{Add, AddAssign, Deref, DerefMut, Range, Sub, SubAssign},
  19    sync::Arc,
  20    usize,
  21};
  22use sum_tree::{Bias, Cursor, Dimensions, FilterCursor, SumTree, Summary, TreeMap};
  23use ui::IntoElement as _;
  24use util::post_inc;
  25
  26#[derive(Clone)]
  27pub struct FoldPlaceholder {
  28    /// Creates an element to represent this fold's placeholder.
  29    pub render: Arc<dyn Send + Sync + Fn(FoldId, Range<Anchor>, &mut App) -> AnyElement>,
  30    /// If true, the element is constrained to the shaped width of an ellipsis.
  31    pub constrain_width: bool,
  32    /// If true, merges the fold with an adjacent one.
  33    pub merge_adjacent: bool,
  34    /// Category of the fold. Useful for carefully removing from overlapping folds.
  35    pub type_tag: Option<TypeId>,
  36    /// Text provided by the language server to display in place of the folded range.
  37    /// When set, this is used instead of the default "⋯" ellipsis.
  38    pub collapsed_text: Option<SharedString>,
  39}
  40
  41impl Default for FoldPlaceholder {
  42    fn default() -> Self {
  43        Self {
  44            render: Arc::new(|_, _, _| gpui::Empty.into_any_element()),
  45            constrain_width: true,
  46            merge_adjacent: true,
  47            type_tag: None,
  48            collapsed_text: None,
  49        }
  50    }
  51}
  52
  53impl FoldPlaceholder {
  54    /// Returns a styled `Div` container with the standard fold‐placeholder
  55    /// look (background, hover, active, rounded corners, full size).
  56    /// Callers add children and event handlers on top.
  57    pub fn fold_element(fold_id: FoldId, cx: &App) -> Stateful<gpui::Div> {
  58        use gpui::{InteractiveElement as _, StatefulInteractiveElement as _, Styled as _};
  59        use settings::Settings as _;
  60        use theme::{ActiveTheme as _, ThemeSettings};
  61        let settings = ThemeSettings::get_global(cx);
  62        gpui::div()
  63            .id(fold_id)
  64            .font(settings.buffer_font.clone())
  65            .text_color(cx.theme().colors().text_placeholder)
  66            .bg(cx.theme().colors().ghost_element_background)
  67            .hover(|style| style.bg(cx.theme().colors().ghost_element_hover))
  68            .active(|style| style.bg(cx.theme().colors().ghost_element_active))
  69            .rounded_xs()
  70            .size_full()
  71    }
  72
  73    #[cfg(any(test, feature = "test-support"))]
  74    pub fn test() -> Self {
  75        Self {
  76            render: Arc::new(|_id, _range, _cx| gpui::Empty.into_any_element()),
  77            constrain_width: true,
  78            merge_adjacent: true,
  79            type_tag: None,
  80            collapsed_text: None,
  81        }
  82    }
  83}
  84
  85impl fmt::Debug for FoldPlaceholder {
  86    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  87        f.debug_struct("FoldPlaceholder")
  88            .field("constrain_width", &self.constrain_width)
  89            .field("collapsed_text", &self.collapsed_text)
  90            .finish()
  91    }
  92}
  93
  94impl Eq for FoldPlaceholder {}
  95
  96impl PartialEq for FoldPlaceholder {
  97    fn eq(&self, other: &Self) -> bool {
  98        Arc::ptr_eq(&self.render, &other.render)
  99            && self.constrain_width == other.constrain_width
 100            && self.collapsed_text == other.collapsed_text
 101    }
 102}
 103
 104#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 105pub struct FoldPoint(pub Point);
 106
 107impl FoldPoint {
 108    pub fn new(row: u32, column: u32) -> Self {
 109        Self(Point::new(row, column))
 110    }
 111
 112    pub fn row(self) -> u32 {
 113        self.0.row
 114    }
 115
 116    pub fn column(self) -> u32 {
 117        self.0.column
 118    }
 119
 120    pub fn row_mut(&mut self) -> &mut u32 {
 121        &mut self.0.row
 122    }
 123
 124    #[cfg(test)]
 125    pub fn column_mut(&mut self) -> &mut u32 {
 126        &mut self.0.column
 127    }
 128
 129    #[ztracing::instrument(skip_all)]
 130    pub fn to_inlay_point(self, snapshot: &FoldSnapshot) -> InlayPoint {
 131        let (start, _, _) = snapshot
 132            .transforms
 133            .find::<Dimensions<FoldPoint, InlayPoint>, _>((), &self, Bias::Right);
 134        let overshoot = self.0 - start.0.0;
 135        InlayPoint(start.1.0 + overshoot)
 136    }
 137
 138    #[ztracing::instrument(skip_all)]
 139    pub fn to_offset(self, snapshot: &FoldSnapshot) -> FoldOffset {
 140        let (start, _, item) = snapshot
 141            .transforms
 142            .find::<Dimensions<FoldPoint, TransformSummary>, _>((), &self, Bias::Right);
 143        let overshoot = self.0 - start.1.output.lines;
 144        let mut offset = start.1.output.len;
 145        if !overshoot.is_zero() {
 146            let transform = item.expect("display point out of range");
 147            assert!(transform.placeholder.is_none());
 148            let end_inlay_offset = snapshot
 149                .inlay_snapshot
 150                .to_offset(InlayPoint(start.1.input.lines + overshoot));
 151            offset += end_inlay_offset.0 - start.1.input.len;
 152        }
 153        FoldOffset(offset)
 154    }
 155}
 156
 157impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
 158    fn zero(_cx: ()) -> Self {
 159        Default::default()
 160    }
 161
 162    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
 163        self.0 += &summary.output.lines;
 164    }
 165}
 166
 167pub(crate) struct FoldMapWriter<'a>(&'a mut FoldMap);
 168
 169impl FoldMapWriter<'_> {
 170    #[ztracing::instrument(skip_all)]
 171    pub(crate) fn fold<T: ToOffset>(
 172        &mut self,
 173        ranges: impl IntoIterator<Item = (Range<T>, FoldPlaceholder)>,
 174    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 175        let mut edits = Vec::new();
 176        let mut folds = Vec::new();
 177        let snapshot = self.0.snapshot.inlay_snapshot.clone();
 178        for (range, fold_text) in ranges.into_iter() {
 179            let buffer = &snapshot.buffer;
 180            let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 181
 182            // Ignore any empty ranges.
 183            if range.start == range.end {
 184                continue;
 185            }
 186
 187            // For now, ignore any ranges that span an excerpt boundary.
 188            let fold_range =
 189                FoldRange(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 190            if fold_range.0.start.excerpt_id != fold_range.0.end.excerpt_id {
 191                continue;
 192            }
 193
 194            folds.push(Fold {
 195                id: FoldId(post_inc(&mut self.0.next_fold_id.0)),
 196                range: fold_range,
 197                placeholder: fold_text,
 198            });
 199
 200            let inlay_range =
 201                snapshot.to_inlay_offset(range.start)..snapshot.to_inlay_offset(range.end);
 202            edits.push(InlayEdit {
 203                old: inlay_range.clone(),
 204                new: inlay_range,
 205            });
 206        }
 207
 208        let buffer = &snapshot.buffer;
 209        folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(&a.range, &b.range, buffer));
 210
 211        self.0.snapshot.folds = {
 212            let mut new_tree = SumTree::new(buffer);
 213            let mut cursor = self.0.snapshot.folds.cursor::<FoldRange>(buffer);
 214            for fold in folds {
 215                self.0.snapshot.fold_metadata_by_id.insert(
 216                    fold.id,
 217                    FoldMetadata {
 218                        range: fold.range.clone(),
 219                        width: None,
 220                    },
 221                );
 222                new_tree.append(cursor.slice(&fold.range, Bias::Right), buffer);
 223                new_tree.push(fold, buffer);
 224            }
 225            new_tree.append(cursor.suffix(), buffer);
 226            new_tree
 227        };
 228
 229        let edits = consolidate_inlay_edits(edits);
 230        let edits = self.0.sync(snapshot.clone(), edits);
 231        (self.0.snapshot.clone(), edits)
 232    }
 233
 234    /// Removes any folds with the given ranges.
 235    #[ztracing::instrument(skip_all)]
 236    pub(crate) fn remove_folds<T: ToOffset>(
 237        &mut self,
 238        ranges: impl IntoIterator<Item = Range<T>>,
 239        type_id: TypeId,
 240    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 241        self.remove_folds_with(
 242            ranges,
 243            |fold| fold.placeholder.type_tag == Some(type_id),
 244            false,
 245        )
 246    }
 247
 248    /// Removes any folds whose ranges intersect the given ranges.
 249    #[ztracing::instrument(skip_all)]
 250    pub(crate) fn unfold_intersecting<T: ToOffset>(
 251        &mut self,
 252        ranges: impl IntoIterator<Item = Range<T>>,
 253        inclusive: bool,
 254    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 255        self.remove_folds_with(ranges, |_| true, inclusive)
 256    }
 257
 258    /// Removes any folds that intersect the given ranges and for which the given predicate
 259    /// returns true.
 260    #[ztracing::instrument(skip_all)]
 261    fn remove_folds_with<T: ToOffset>(
 262        &mut self,
 263        ranges: impl IntoIterator<Item = Range<T>>,
 264        should_unfold: impl Fn(&Fold) -> bool,
 265        inclusive: bool,
 266    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 267        let mut edits = Vec::new();
 268        let mut fold_ixs_to_delete = Vec::new();
 269        let snapshot = self.0.snapshot.inlay_snapshot.clone();
 270        let buffer = &snapshot.buffer;
 271        for range in ranges.into_iter() {
 272            let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 273            let mut folds_cursor =
 274                intersecting_folds(&snapshot, &self.0.snapshot.folds, range.clone(), inclusive);
 275            while let Some(fold) = folds_cursor.item() {
 276                let offset_range =
 277                    fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer);
 278                if should_unfold(fold) {
 279                    if offset_range.end > offset_range.start {
 280                        let inlay_range = snapshot.to_inlay_offset(offset_range.start)
 281                            ..snapshot.to_inlay_offset(offset_range.end);
 282                        edits.push(InlayEdit {
 283                            old: inlay_range.clone(),
 284                            new: inlay_range,
 285                        });
 286                    }
 287                    fold_ixs_to_delete.push(*folds_cursor.start());
 288                    self.0.snapshot.fold_metadata_by_id.remove(&fold.id);
 289                }
 290                folds_cursor.next();
 291            }
 292        }
 293
 294        fold_ixs_to_delete.sort_unstable();
 295        fold_ixs_to_delete.dedup();
 296
 297        self.0.snapshot.folds = {
 298            let mut cursor = self.0.snapshot.folds.cursor::<MultiBufferOffset>(buffer);
 299            let mut folds = SumTree::new(buffer);
 300            for fold_ix in fold_ixs_to_delete {
 301                folds.append(cursor.slice(&fold_ix, Bias::Right), buffer);
 302                cursor.next();
 303            }
 304            folds.append(cursor.suffix(), buffer);
 305            folds
 306        };
 307
 308        let edits = consolidate_inlay_edits(edits);
 309        let edits = self.0.sync(snapshot.clone(), edits);
 310        (self.0.snapshot.clone(), edits)
 311    }
 312
 313    #[ztracing::instrument(skip_all)]
 314    pub(crate) fn update_fold_widths(
 315        &mut self,
 316        new_widths: impl IntoIterator<Item = (ChunkRendererId, Pixels)>,
 317    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 318        let mut edits = Vec::new();
 319        let inlay_snapshot = self.0.snapshot.inlay_snapshot.clone();
 320        let buffer = &inlay_snapshot.buffer;
 321
 322        for (id, new_width) in new_widths {
 323            let ChunkRendererId::Fold(id) = id else {
 324                continue;
 325            };
 326            if let Some(metadata) = self.0.snapshot.fold_metadata_by_id.get(&id).cloned()
 327                && Some(new_width) != metadata.width
 328            {
 329                let buffer_start = metadata.range.start.to_offset(buffer);
 330                let buffer_end = metadata.range.end.to_offset(buffer);
 331                let inlay_range = inlay_snapshot.to_inlay_offset(buffer_start)
 332                    ..inlay_snapshot.to_inlay_offset(buffer_end);
 333                edits.push(InlayEdit {
 334                    old: inlay_range.clone(),
 335                    new: inlay_range.clone(),
 336                });
 337
 338                self.0.snapshot.fold_metadata_by_id.insert(
 339                    id,
 340                    FoldMetadata {
 341                        range: metadata.range,
 342                        width: Some(new_width),
 343                    },
 344                );
 345            }
 346        }
 347
 348        let edits = consolidate_inlay_edits(edits);
 349        let edits = self.0.sync(inlay_snapshot, edits);
 350        (self.0.snapshot.clone(), edits)
 351    }
 352}
 353
 354/// Decides where the fold indicators should be; also tracks parts of a source file that are currently folded.
 355///
 356/// See the [`display_map` module documentation](crate::display_map) for more information.
 357pub struct FoldMap {
 358    snapshot: FoldSnapshot,
 359    next_fold_id: FoldId,
 360}
 361
 362impl FoldMap {
 363    #[ztracing::instrument(skip_all)]
 364    pub fn new(inlay_snapshot: InlaySnapshot) -> (Self, FoldSnapshot) {
 365        let this = Self {
 366            snapshot: FoldSnapshot {
 367                folds: SumTree::new(&inlay_snapshot.buffer),
 368                transforms: SumTree::from_item(
 369                    Transform {
 370                        summary: TransformSummary {
 371                            input: inlay_snapshot.text_summary(),
 372                            output: inlay_snapshot.text_summary(),
 373                        },
 374                        placeholder: None,
 375                    },
 376                    (),
 377                ),
 378                inlay_snapshot: inlay_snapshot,
 379                version: 0,
 380                fold_metadata_by_id: TreeMap::default(),
 381            },
 382            next_fold_id: FoldId::default(),
 383        };
 384        let snapshot = this.snapshot.clone();
 385        (this, snapshot)
 386    }
 387
 388    #[ztracing::instrument(skip_all)]
 389    pub fn read(
 390        &mut self,
 391        inlay_snapshot: InlaySnapshot,
 392        edits: Vec<InlayEdit>,
 393    ) -> (FoldSnapshot, Vec<FoldEdit>) {
 394        let edits = self.sync(inlay_snapshot, edits);
 395        self.check_invariants();
 396        (self.snapshot.clone(), edits)
 397    }
 398
 399    #[ztracing::instrument(skip_all)]
 400    pub(crate) fn write(
 401        &mut self,
 402        inlay_snapshot: InlaySnapshot,
 403        edits: Vec<InlayEdit>,
 404    ) -> (FoldMapWriter<'_>, FoldSnapshot, Vec<FoldEdit>) {
 405        let (snapshot, edits) = self.read(inlay_snapshot, edits);
 406        (FoldMapWriter(self), snapshot, edits)
 407    }
 408
 409    #[ztracing::instrument(skip_all)]
 410    fn check_invariants(&self) {
 411        if cfg!(test) {
 412            assert_eq!(
 413                self.snapshot.transforms.summary().input.len,
 414                self.snapshot.inlay_snapshot.len().0,
 415                "transform tree does not match inlay snapshot's length"
 416            );
 417
 418            let mut prev_transform_isomorphic = false;
 419            for transform in self.snapshot.transforms.iter() {
 420                if !transform.is_fold() && prev_transform_isomorphic {
 421                    panic!(
 422                        "found adjacent isomorphic transforms: {:?}",
 423                        self.snapshot.transforms.items(())
 424                    );
 425                }
 426                prev_transform_isomorphic = !transform.is_fold();
 427            }
 428
 429            let mut folds = self.snapshot.folds.iter().peekable();
 430            while let Some(fold) = folds.next() {
 431                if let Some(next_fold) = folds.peek() {
 432                    let comparison = fold.range.cmp(&next_fold.range, self.snapshot.buffer());
 433                    assert!(comparison.is_le());
 434                }
 435            }
 436        }
 437    }
 438
 439    #[ztracing::instrument(skip_all)]
 440    fn sync(
 441        &mut self,
 442        inlay_snapshot: InlaySnapshot,
 443        inlay_edits: Vec<InlayEdit>,
 444    ) -> Vec<FoldEdit> {
 445        if inlay_edits.is_empty() {
 446            if self.snapshot.inlay_snapshot.version != inlay_snapshot.version {
 447                self.snapshot.version += 1;
 448            }
 449            self.snapshot.inlay_snapshot = inlay_snapshot;
 450            Vec::new()
 451        } else {
 452            let mut inlay_edits_iter = inlay_edits.iter().cloned().peekable();
 453
 454            let mut new_transforms = SumTree::<Transform>::default();
 455            let mut cursor = self.snapshot.transforms.cursor::<InlayOffset>(());
 456            cursor.seek(&InlayOffset(MultiBufferOffset(0)), Bias::Right);
 457
 458            while let Some(mut edit) = inlay_edits_iter.next() {
 459                if let Some(item) = cursor.item()
 460                    && !item.is_fold()
 461                {
 462                    new_transforms.update_last(
 463                        |transform| {
 464                            if !transform.is_fold() {
 465                                transform.summary.add_summary(&item.summary, ());
 466                                cursor.next();
 467                            }
 468                        },
 469                        (),
 470                    );
 471                }
 472                new_transforms.append(cursor.slice(&edit.old.start, Bias::Left), ());
 473                edit.new.start -= edit.old.start - *cursor.start();
 474                edit.old.start = *cursor.start();
 475
 476                cursor.seek(&edit.old.end, Bias::Right);
 477                cursor.next();
 478
 479                let mut delta = edit.new_len() as isize - edit.old_len() as isize;
 480                loop {
 481                    edit.old.end = *cursor.start();
 482
 483                    if let Some(next_edit) = inlay_edits_iter.peek() {
 484                        if next_edit.old.start > edit.old.end {
 485                            break;
 486                        }
 487
 488                        let next_edit = inlay_edits_iter.next().unwrap();
 489                        delta += next_edit.new_len() as isize - next_edit.old_len() as isize;
 490
 491                        if next_edit.old.end >= edit.old.end {
 492                            edit.old.end = next_edit.old.end;
 493                            cursor.seek(&edit.old.end, Bias::Right);
 494                            cursor.next();
 495                        }
 496                    } else {
 497                        break;
 498                    }
 499                }
 500
 501                edit.new.end = InlayOffset(MultiBufferOffset(
 502                    ((edit.new.start + edit.old_len()).0.0 as isize + delta) as usize,
 503                ));
 504
 505                let anchor = inlay_snapshot
 506                    .buffer
 507                    .anchor_before(inlay_snapshot.to_buffer_offset(edit.new.start));
 508                let mut folds_cursor = self
 509                    .snapshot
 510                    .folds
 511                    .cursor::<FoldRange>(&inlay_snapshot.buffer);
 512                folds_cursor.seek(&FoldRange(anchor..Anchor::max()), Bias::Left);
 513
 514                let mut folds = iter::from_fn({
 515                    let inlay_snapshot = &inlay_snapshot;
 516                    move || {
 517                        let item = folds_cursor.item().map(|fold| {
 518                            let buffer_start = fold.range.start.to_offset(&inlay_snapshot.buffer);
 519                            let buffer_end = fold.range.end.to_offset(&inlay_snapshot.buffer);
 520                            (
 521                                fold.clone(),
 522                                inlay_snapshot.to_inlay_offset(buffer_start)
 523                                    ..inlay_snapshot.to_inlay_offset(buffer_end),
 524                            )
 525                        });
 526                        folds_cursor.next();
 527                        item
 528                    }
 529                })
 530                .peekable();
 531
 532                while folds
 533                    .peek()
 534                    .is_some_and(|(_, fold_range)| fold_range.start < edit.new.end)
 535                {
 536                    let (fold, mut fold_range) = folds.next().unwrap();
 537                    let sum = new_transforms.summary();
 538
 539                    assert!(fold_range.start.0 >= sum.input.len);
 540
 541                    while folds.peek().is_some_and(|(next_fold, next_fold_range)| {
 542                        next_fold_range.start < fold_range.end
 543                            || (next_fold_range.start == fold_range.end
 544                                && fold.placeholder.merge_adjacent
 545                                && next_fold.placeholder.merge_adjacent)
 546                    }) {
 547                        let (_, next_fold_range) = folds.next().unwrap();
 548                        if next_fold_range.end > fold_range.end {
 549                            fold_range.end = next_fold_range.end;
 550                        }
 551                    }
 552
 553                    if fold_range.start.0 > sum.input.len {
 554                        let text_summary = inlay_snapshot
 555                            .text_summary_for_range(InlayOffset(sum.input.len)..fold_range.start);
 556                        push_isomorphic(&mut new_transforms, text_summary);
 557                    }
 558
 559                    if fold_range.end > fold_range.start {
 560                        const ELLIPSIS: &str = "";
 561
 562                        let placeholder_text: SharedString = fold
 563                            .placeholder
 564                            .collapsed_text
 565                            .clone()
 566                            .unwrap_or_else(|| ELLIPSIS.into());
 567                        let chars_bitmap = placeholder_text
 568                            .char_indices()
 569                            .fold(0u128, |bitmap, (idx, _)| {
 570                                bitmap | 1u128.unbounded_shl(idx as u32)
 571                            });
 572
 573                        let fold_id = fold.id;
 574                        new_transforms.push(
 575                            Transform {
 576                                summary: TransformSummary {
 577                                    output: MBTextSummary::from(placeholder_text.as_ref()),
 578                                    input: inlay_snapshot
 579                                        .text_summary_for_range(fold_range.start..fold_range.end),
 580                                },
 581                                placeholder: Some(TransformPlaceholder {
 582                                    text: placeholder_text,
 583                                    chars: chars_bitmap,
 584                                    renderer: ChunkRenderer {
 585                                        id: ChunkRendererId::Fold(fold.id),
 586                                        render: Arc::new(move |cx| {
 587                                            (fold.placeholder.render)(
 588                                                fold_id,
 589                                                fold.range.0.clone(),
 590                                                cx.context,
 591                                            )
 592                                        }),
 593                                        constrain_width: fold.placeholder.constrain_width,
 594                                        measured_width: self.snapshot.fold_width(&fold_id),
 595                                    },
 596                                }),
 597                            },
 598                            (),
 599                        );
 600                    }
 601                }
 602
 603                let sum = new_transforms.summary();
 604                if sum.input.len < edit.new.end.0 {
 605                    let text_summary = inlay_snapshot
 606                        .text_summary_for_range(InlayOffset(sum.input.len)..edit.new.end);
 607                    push_isomorphic(&mut new_transforms, text_summary);
 608                }
 609            }
 610
 611            new_transforms.append(cursor.suffix(), ());
 612            if new_transforms.is_empty() {
 613                let text_summary = inlay_snapshot.text_summary();
 614                push_isomorphic(&mut new_transforms, text_summary);
 615            }
 616
 617            drop(cursor);
 618
 619            let mut fold_edits = Vec::with_capacity(inlay_edits.len());
 620            {
 621                let mut old_transforms = self
 622                    .snapshot
 623                    .transforms
 624                    .cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 625                let mut new_transforms =
 626                    new_transforms.cursor::<Dimensions<InlayOffset, FoldOffset>>(());
 627
 628                for mut edit in inlay_edits {
 629                    old_transforms.seek(&edit.old.start, Bias::Left);
 630                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 631                        edit.old.start = old_transforms.start().0;
 632                    }
 633                    let old_start =
 634                        old_transforms.start().1.0 + (edit.old.start - old_transforms.start().0);
 635
 636                    old_transforms.seek_forward(&edit.old.end, Bias::Right);
 637                    if old_transforms.item().is_some_and(|t| t.is_fold()) {
 638                        old_transforms.next();
 639                        edit.old.end = old_transforms.start().0;
 640                    }
 641                    let old_end =
 642                        old_transforms.start().1.0 + (edit.old.end - old_transforms.start().0);
 643
 644                    new_transforms.seek(&edit.new.start, Bias::Left);
 645                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 646                        edit.new.start = new_transforms.start().0;
 647                    }
 648                    let new_start =
 649                        new_transforms.start().1.0 + (edit.new.start - new_transforms.start().0);
 650
 651                    new_transforms.seek_forward(&edit.new.end, Bias::Right);
 652                    if new_transforms.item().is_some_and(|t| t.is_fold()) {
 653                        new_transforms.next();
 654                        edit.new.end = new_transforms.start().0;
 655                    }
 656                    let new_end =
 657                        new_transforms.start().1.0 + (edit.new.end - new_transforms.start().0);
 658
 659                    fold_edits.push(FoldEdit {
 660                        old: FoldOffset(old_start)..FoldOffset(old_end),
 661                        new: FoldOffset(new_start)..FoldOffset(new_end),
 662                    });
 663                }
 664
 665                fold_edits = consolidate_fold_edits(fold_edits);
 666            }
 667
 668            self.snapshot.transforms = new_transforms;
 669            self.snapshot.inlay_snapshot = inlay_snapshot;
 670            self.snapshot.version += 1;
 671            fold_edits
 672        }
 673    }
 674}
 675
 676#[derive(Clone)]
 677pub struct FoldSnapshot {
 678    pub inlay_snapshot: InlaySnapshot,
 679    transforms: SumTree<Transform>,
 680    folds: SumTree<Fold>,
 681    fold_metadata_by_id: TreeMap<FoldId, FoldMetadata>,
 682    pub version: usize,
 683}
 684
 685impl Deref for FoldSnapshot {
 686    type Target = InlaySnapshot;
 687
 688    fn deref(&self) -> &Self::Target {
 689        &self.inlay_snapshot
 690    }
 691}
 692
 693impl FoldSnapshot {
 694    pub fn buffer(&self) -> &MultiBufferSnapshot {
 695        &self.inlay_snapshot.buffer
 696    }
 697
 698    #[ztracing::instrument(skip_all)]
 699    fn fold_width(&self, fold_id: &FoldId) -> Option<Pixels> {
 700        self.fold_metadata_by_id.get(fold_id)?.width
 701    }
 702
 703    #[cfg(test)]
 704    pub fn text(&self) -> String {
 705        self.chunks(
 706            FoldOffset(MultiBufferOffset(0))..self.len(),
 707            false,
 708            Highlights::default(),
 709        )
 710        .map(|c| c.text)
 711        .collect()
 712    }
 713
 714    #[cfg(test)]
 715    pub fn fold_count(&self) -> usize {
 716        self.folds.items(&self.inlay_snapshot.buffer).len()
 717    }
 718
 719    #[ztracing::instrument(skip_all)]
 720    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> MBTextSummary {
 721        let mut summary = MBTextSummary::default();
 722
 723        let mut cursor = self
 724            .transforms
 725            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 726        cursor.seek(&range.start, Bias::Right);
 727        if let Some(transform) = cursor.item() {
 728            let start_in_transform = range.start.0 - cursor.start().0.0;
 729            let end_in_transform = cmp::min(range.end, cursor.end().0).0 - cursor.start().0.0;
 730            if let Some(placeholder) = transform.placeholder.as_ref() {
 731                summary = MBTextSummary::from(
 732                    &placeholder.text.as_ref()
 733                        [start_in_transform.column as usize..end_in_transform.column as usize],
 734                );
 735            } else {
 736                let inlay_start = self
 737                    .inlay_snapshot
 738                    .to_offset(InlayPoint(cursor.start().1.0 + start_in_transform));
 739                let inlay_end = self
 740                    .inlay_snapshot
 741                    .to_offset(InlayPoint(cursor.start().1.0 + end_in_transform));
 742                summary = self
 743                    .inlay_snapshot
 744                    .text_summary_for_range(inlay_start..inlay_end);
 745            }
 746        }
 747
 748        if range.end > cursor.end().0 {
 749            cursor.next();
 750            summary += cursor
 751                .summary::<_, TransformSummary>(&range.end, Bias::Right)
 752                .output;
 753            if let Some(transform) = cursor.item() {
 754                let end_in_transform = range.end.0 - cursor.start().0.0;
 755                if let Some(placeholder) = transform.placeholder.as_ref() {
 756                    summary += MBTextSummary::from(
 757                        &placeholder.text.as_ref()[..end_in_transform.column as usize],
 758                    );
 759                } else {
 760                    let inlay_start = self.inlay_snapshot.to_offset(cursor.start().1);
 761                    let inlay_end = self
 762                        .inlay_snapshot
 763                        .to_offset(InlayPoint(cursor.start().1.0 + end_in_transform));
 764                    summary += self
 765                        .inlay_snapshot
 766                        .text_summary_for_range(inlay_start..inlay_end);
 767                }
 768            }
 769        }
 770
 771        summary
 772    }
 773
 774    #[ztracing::instrument(skip_all)]
 775    pub fn to_fold_point(&self, point: InlayPoint, bias: Bias) -> FoldPoint {
 776        let (start, end, item) = self
 777            .transforms
 778            .find::<Dimensions<InlayPoint, FoldPoint>, _>((), &point, Bias::Right);
 779        if item.is_some_and(|t| t.is_fold()) {
 780            if bias == Bias::Left || point == start.0 {
 781                start.1
 782            } else {
 783                end.1
 784            }
 785        } else {
 786            let overshoot = point.0 - start.0.0;
 787            FoldPoint(cmp::min(start.1.0 + overshoot, end.1.0))
 788        }
 789    }
 790
 791    #[ztracing::instrument(skip_all)]
 792    pub fn fold_point_cursor(&self) -> FoldPointCursor<'_> {
 793        let cursor = self
 794            .transforms
 795            .cursor::<Dimensions<InlayPoint, FoldPoint>>(());
 796        FoldPointCursor { cursor }
 797    }
 798
 799    #[ztracing::instrument(skip_all)]
 800    pub fn len(&self) -> FoldOffset {
 801        FoldOffset(self.transforms.summary().output.len)
 802    }
 803
 804    #[ztracing::instrument(skip_all)]
 805    pub fn line_len(&self, row: u32) -> u32 {
 806        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 807        let line_end = if row >= self.max_point().row() {
 808            self.len().0
 809        } else {
 810            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 811        };
 812        (line_end - line_start) as u32
 813    }
 814
 815    #[ztracing::instrument(skip_all)]
 816    pub fn row_infos(&self, start_row: u32) -> FoldRows<'_> {
 817        if start_row > self.transforms.summary().output.lines.row {
 818            panic!("invalid display row {}", start_row);
 819        }
 820
 821        let fold_point = FoldPoint::new(start_row, 0);
 822        let mut cursor = self
 823            .transforms
 824            .cursor::<Dimensions<FoldPoint, InlayPoint>>(());
 825        cursor.seek(&fold_point, Bias::Left);
 826
 827        let overshoot = fold_point.0 - cursor.start().0.0;
 828        let inlay_point = InlayPoint(cursor.start().1.0 + overshoot);
 829        let input_rows = self.inlay_snapshot.row_infos(inlay_point.row());
 830
 831        FoldRows {
 832            fold_point,
 833            input_rows,
 834            cursor,
 835        }
 836    }
 837
 838    #[ztracing::instrument(skip_all)]
 839    pub fn max_point(&self) -> FoldPoint {
 840        FoldPoint(self.transforms.summary().output.lines)
 841    }
 842
 843    #[cfg(test)]
 844    pub fn longest_row(&self) -> u32 {
 845        self.transforms.summary().output.longest_row
 846    }
 847
 848    #[ztracing::instrument(skip_all)]
 849    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Fold>
 850    where
 851        T: ToOffset,
 852    {
 853        let buffer = &self.inlay_snapshot.buffer;
 854        let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 855        let mut folds = intersecting_folds(&self.inlay_snapshot, &self.folds, range, false);
 856        iter::from_fn(move || {
 857            let item = folds.item();
 858            folds.next();
 859            item
 860        })
 861    }
 862
 863    #[ztracing::instrument(skip_all)]
 864    pub fn intersects_fold<T>(&self, offset: T) -> bool
 865    where
 866        T: ToOffset,
 867    {
 868        let buffer_offset = offset.to_offset(&self.inlay_snapshot.buffer);
 869        let inlay_offset = self.inlay_snapshot.to_inlay_offset(buffer_offset);
 870        let (_, _, item) = self
 871            .transforms
 872            .find::<InlayOffset, _>((), &inlay_offset, Bias::Right);
 873        item.is_some_and(|t| t.placeholder.is_some())
 874    }
 875
 876    #[ztracing::instrument(skip_all)]
 877    pub fn is_line_folded(&self, buffer_row: MultiBufferRow) -> bool {
 878        let mut inlay_point = self
 879            .inlay_snapshot
 880            .to_inlay_point(Point::new(buffer_row.0, 0));
 881        let mut cursor = self.transforms.cursor::<InlayPoint>(());
 882        cursor.seek(&inlay_point, Bias::Right);
 883        loop {
 884            match cursor.item() {
 885                Some(transform) => {
 886                    let buffer_point = self.inlay_snapshot.to_buffer_point(inlay_point);
 887                    if buffer_point.row != buffer_row.0 {
 888                        return false;
 889                    } else if transform.placeholder.is_some() {
 890                        return true;
 891                    }
 892                }
 893                None => return false,
 894            }
 895
 896            if cursor.end().row() == inlay_point.row() {
 897                cursor.next();
 898            } else {
 899                inlay_point.0 += Point::new(1, 0);
 900                cursor.seek(&inlay_point, Bias::Right);
 901            }
 902        }
 903    }
 904
 905    #[ztracing::instrument(skip_all)]
 906    pub(crate) fn chunks<'a>(
 907        &'a self,
 908        range: Range<FoldOffset>,
 909        language_aware: bool,
 910        highlights: Highlights<'a>,
 911    ) -> FoldChunks<'a> {
 912        let mut transform_cursor = self
 913            .transforms
 914            .cursor::<Dimensions<FoldOffset, InlayOffset>>(());
 915        transform_cursor.seek(&range.start, Bias::Right);
 916
 917        let inlay_start = {
 918            let overshoot = range.start - transform_cursor.start().0;
 919            transform_cursor.start().1 + overshoot
 920        };
 921
 922        let transform_end = transform_cursor.end();
 923
 924        let inlay_end = if transform_cursor
 925            .item()
 926            .is_none_or(|transform| transform.is_fold())
 927        {
 928            inlay_start
 929        } else if range.end < transform_end.0 {
 930            let overshoot = range.end - transform_cursor.start().0;
 931            transform_cursor.start().1 + overshoot
 932        } else {
 933            transform_end.1
 934        };
 935
 936        FoldChunks {
 937            transform_cursor,
 938            inlay_chunks: self.inlay_snapshot.chunks(
 939                inlay_start..inlay_end,
 940                language_aware,
 941                highlights,
 942            ),
 943            inlay_chunk: None,
 944            inlay_offset: inlay_start,
 945            output_offset: range.start,
 946            max_output_offset: range.end,
 947        }
 948    }
 949
 950    #[ztracing::instrument(skip_all)]
 951    pub fn chars_at(&self, start: FoldPoint) -> impl '_ + Iterator<Item = char> {
 952        self.chunks(
 953            start.to_offset(self)..self.len(),
 954            false,
 955            Highlights::default(),
 956        )
 957        .flat_map(|chunk| chunk.text.chars())
 958    }
 959
 960    #[ztracing::instrument(skip_all)]
 961    pub fn chunks_at(&self, start: FoldPoint) -> FoldChunks<'_> {
 962        self.chunks(
 963            start.to_offset(self)..self.len(),
 964            false,
 965            Highlights::default(),
 966        )
 967    }
 968
 969    #[cfg(test)]
 970    #[ztracing::instrument(skip_all)]
 971    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 972        if offset > self.len() {
 973            self.len()
 974        } else {
 975            self.clip_point(offset.to_point(self), bias).to_offset(self)
 976        }
 977    }
 978
 979    #[ztracing::instrument(skip_all)]
 980    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 981        let (start, end, item) = self
 982            .transforms
 983            .find::<Dimensions<FoldPoint, InlayPoint>, _>((), &point, Bias::Right);
 984        if let Some(transform) = item {
 985            let transform_start = start.0.0;
 986            if transform.placeholder.is_some() {
 987                if point.0 == transform_start || matches!(bias, Bias::Left) {
 988                    FoldPoint(transform_start)
 989                } else {
 990                    FoldPoint(end.0.0)
 991                }
 992            } else {
 993                let overshoot = InlayPoint(point.0 - transform_start);
 994                let inlay_point = start.1 + overshoot;
 995                let clipped_inlay_point = self.inlay_snapshot.clip_point(inlay_point, bias);
 996                FoldPoint(start.0.0 + (clipped_inlay_point - start.1).0)
 997            }
 998        } else {
 999            FoldPoint(self.transforms.summary().output.lines)
1000        }
1001    }
1002}
1003
1004pub struct FoldPointCursor<'transforms> {
1005    cursor: Cursor<'transforms, 'static, Transform, Dimensions<InlayPoint, FoldPoint>>,
1006}
1007
1008impl FoldPointCursor<'_> {
1009    #[ztracing::instrument(skip_all)]
1010    pub fn map(&mut self, point: InlayPoint, bias: Bias) -> FoldPoint {
1011        let cursor = &mut self.cursor;
1012        if cursor.did_seek() {
1013            cursor.seek_forward(&point, Bias::Right);
1014        } else {
1015            cursor.seek(&point, Bias::Right);
1016        }
1017        if cursor.item().is_some_and(|t| t.is_fold()) {
1018            if bias == Bias::Left || point == cursor.start().0 {
1019                cursor.start().1
1020            } else {
1021                cursor.end().1
1022            }
1023        } else {
1024            let overshoot = point.0 - cursor.start().0.0;
1025            FoldPoint(cmp::min(cursor.start().1.0 + overshoot, cursor.end().1.0))
1026        }
1027    }
1028}
1029
1030fn push_isomorphic(transforms: &mut SumTree<Transform>, summary: MBTextSummary) {
1031    let mut did_merge = false;
1032    transforms.update_last(
1033        |last| {
1034            if !last.is_fold() {
1035                last.summary.input += summary;
1036                last.summary.output += summary;
1037                did_merge = true;
1038            }
1039        },
1040        (),
1041    );
1042    if !did_merge {
1043        transforms.push(
1044            Transform {
1045                summary: TransformSummary {
1046                    input: summary,
1047                    output: summary,
1048                },
1049                placeholder: None,
1050            },
1051            (),
1052        )
1053    }
1054}
1055
1056fn intersecting_folds<'a>(
1057    inlay_snapshot: &'a InlaySnapshot,
1058    folds: &'a SumTree<Fold>,
1059    range: Range<MultiBufferOffset>,
1060    inclusive: bool,
1061) -> FilterCursor<'a, 'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, MultiBufferOffset> {
1062    let buffer = &inlay_snapshot.buffer;
1063    let start = buffer.anchor_before(range.start.to_offset(buffer));
1064    let end = buffer.anchor_after(range.end.to_offset(buffer));
1065    let mut cursor = folds.filter::<_, MultiBufferOffset>(buffer, move |summary| {
1066        let start_cmp = start.cmp(&summary.max_end, buffer);
1067        let end_cmp = end.cmp(&summary.min_start, buffer);
1068
1069        if inclusive {
1070            start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
1071        } else {
1072            start_cmp == Ordering::Less && end_cmp == Ordering::Greater
1073        }
1074    });
1075    cursor.next();
1076    cursor
1077}
1078
1079fn consolidate_inlay_edits(mut edits: Vec<InlayEdit>) -> Vec<InlayEdit> {
1080    edits.sort_unstable_by(|a, b| {
1081        a.old
1082            .start
1083            .cmp(&b.old.start)
1084            .then_with(|| b.old.end.cmp(&a.old.end))
1085    });
1086
1087    let _old_alloc_ptr = edits.as_ptr();
1088    let mut inlay_edits = edits.into_iter();
1089
1090    if let Some(mut first_edit) = inlay_edits.next() {
1091        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
1092        #[allow(clippy::filter_map_identity)]
1093        let mut v: Vec<_> = inlay_edits
1094            .scan(&mut first_edit, |prev_edit, edit| {
1095                if prev_edit.old.end >= edit.old.start {
1096                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
1097                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
1098                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
1099                    Some(None) // Skip this edit, it's merged
1100                } else {
1101                    let prev = std::mem::replace(*prev_edit, edit);
1102                    Some(Some(prev)) // Yield the previous edit
1103                }
1104            })
1105            .filter_map(|x| x)
1106            .collect();
1107        v.push(first_edit.clone());
1108        debug_assert_eq!(_old_alloc_ptr, v.as_ptr(), "Inlay edits were reallocated");
1109        v
1110    } else {
1111        vec![]
1112    }
1113}
1114
1115fn consolidate_fold_edits(mut edits: Vec<FoldEdit>) -> Vec<FoldEdit> {
1116    edits.sort_unstable_by(|a, b| {
1117        a.old
1118            .start
1119            .cmp(&b.old.start)
1120            .then_with(|| b.old.end.cmp(&a.old.end))
1121    });
1122    let _old_alloc_ptr = edits.as_ptr();
1123    let mut fold_edits = edits.into_iter();
1124
1125    if let Some(mut first_edit) = fold_edits.next() {
1126        // This code relies on reusing allocations from the Vec<_> - at the time of writing .flatten() prevents them.
1127        #[allow(clippy::filter_map_identity)]
1128        let mut v: Vec<_> = fold_edits
1129            .scan(&mut first_edit, |prev_edit, edit| {
1130                if prev_edit.old.end >= edit.old.start {
1131                    prev_edit.old.end = prev_edit.old.end.max(edit.old.end);
1132                    prev_edit.new.start = prev_edit.new.start.min(edit.new.start);
1133                    prev_edit.new.end = prev_edit.new.end.max(edit.new.end);
1134                    Some(None) // Skip this edit, it's merged
1135                } else {
1136                    let prev = std::mem::replace(*prev_edit, edit);
1137                    Some(Some(prev)) // Yield the previous edit
1138                }
1139            })
1140            .filter_map(|x| x)
1141            .collect();
1142        v.push(first_edit.clone());
1143        v
1144    } else {
1145        vec![]
1146    }
1147}
1148
1149#[derive(Clone, Debug, Default)]
1150struct Transform {
1151    summary: TransformSummary,
1152    placeholder: Option<TransformPlaceholder>,
1153}
1154
1155#[derive(Clone, Debug)]
1156struct TransformPlaceholder {
1157    text: SharedString,
1158    chars: u128,
1159    renderer: ChunkRenderer,
1160}
1161
1162impl Transform {
1163    fn is_fold(&self) -> bool {
1164        self.placeholder.is_some()
1165    }
1166}
1167
1168#[derive(Clone, Debug, Default, Eq, PartialEq)]
1169struct TransformSummary {
1170    output: MBTextSummary,
1171    input: MBTextSummary,
1172}
1173
1174impl sum_tree::Item for Transform {
1175    type Summary = TransformSummary;
1176
1177    fn summary(&self, _cx: ()) -> Self::Summary {
1178        self.summary.clone()
1179    }
1180}
1181
1182impl sum_tree::ContextLessSummary for TransformSummary {
1183    fn zero() -> Self {
1184        Default::default()
1185    }
1186
1187    fn add_summary(&mut self, other: &Self) {
1188        self.input += other.input;
1189        self.output += other.output;
1190    }
1191}
1192
1193#[derive(Copy, Clone, Eq, PartialEq, Debug, Default, Ord, PartialOrd, Hash)]
1194pub struct FoldId(pub(super) usize);
1195
1196impl From<FoldId> for ElementId {
1197    fn from(val: FoldId) -> Self {
1198        val.0.into()
1199    }
1200}
1201
1202#[derive(Clone, Debug, Eq, PartialEq)]
1203pub struct Fold {
1204    pub id: FoldId,
1205    pub range: FoldRange,
1206    pub placeholder: FoldPlaceholder,
1207}
1208
1209#[derive(Clone, Debug, Eq, PartialEq)]
1210pub struct FoldRange(pub(crate) Range<Anchor>);
1211
1212impl Deref for FoldRange {
1213    type Target = Range<Anchor>;
1214
1215    fn deref(&self) -> &Self::Target {
1216        &self.0
1217    }
1218}
1219
1220impl DerefMut for FoldRange {
1221    fn deref_mut(&mut self) -> &mut Self::Target {
1222        &mut self.0
1223    }
1224}
1225
1226impl Default for FoldRange {
1227    fn default() -> Self {
1228        Self(Anchor::min()..Anchor::max())
1229    }
1230}
1231
1232#[derive(Clone, Debug)]
1233struct FoldMetadata {
1234    range: FoldRange,
1235    width: Option<Pixels>,
1236}
1237
1238impl sum_tree::Item for Fold {
1239    type Summary = FoldSummary;
1240
1241    fn summary(&self, _cx: &MultiBufferSnapshot) -> Self::Summary {
1242        FoldSummary {
1243            start: self.range.start,
1244            end: self.range.end,
1245            min_start: self.range.start,
1246            max_end: self.range.end,
1247            count: 1,
1248        }
1249    }
1250}
1251
1252#[derive(Clone, Debug)]
1253pub struct FoldSummary {
1254    start: Anchor,
1255    end: Anchor,
1256    min_start: Anchor,
1257    max_end: Anchor,
1258    count: usize,
1259}
1260
1261impl Default for FoldSummary {
1262    fn default() -> Self {
1263        Self {
1264            start: Anchor::min(),
1265            end: Anchor::max(),
1266            min_start: Anchor::max(),
1267            max_end: Anchor::min(),
1268            count: 0,
1269        }
1270    }
1271}
1272
1273impl sum_tree::Summary for FoldSummary {
1274    type Context<'a> = &'a MultiBufferSnapshot;
1275
1276    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1277        Default::default()
1278    }
1279
1280    fn add_summary(&mut self, other: &Self, buffer: Self::Context<'_>) {
1281        if other.min_start.cmp(&self.min_start, buffer) == Ordering::Less {
1282            self.min_start = other.min_start;
1283        }
1284        if other.max_end.cmp(&self.max_end, buffer) == Ordering::Greater {
1285            self.max_end = other.max_end;
1286        }
1287
1288        #[cfg(debug_assertions)]
1289        {
1290            let start_comparison = self.start.cmp(&other.start, buffer);
1291            assert!(start_comparison <= Ordering::Equal);
1292            if start_comparison == Ordering::Equal {
1293                assert!(self.end.cmp(&other.end, buffer) >= Ordering::Equal);
1294            }
1295        }
1296
1297        self.start = other.start;
1298        self.end = other.end;
1299        self.count += other.count;
1300    }
1301}
1302
1303impl<'a> sum_tree::Dimension<'a, FoldSummary> for FoldRange {
1304    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1305        Default::default()
1306    }
1307
1308    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1309        self.0.start = summary.start;
1310        self.0.end = summary.end;
1311    }
1312}
1313
1314impl sum_tree::SeekTarget<'_, FoldSummary, FoldRange> for FoldRange {
1315    fn cmp(&self, other: &Self, buffer: &MultiBufferSnapshot) -> Ordering {
1316        AnchorRangeExt::cmp(&self.0, &other.0, buffer)
1317    }
1318}
1319
1320impl<'a> sum_tree::Dimension<'a, FoldSummary> for MultiBufferOffset {
1321    fn zero(_cx: &MultiBufferSnapshot) -> Self {
1322        Default::default()
1323    }
1324
1325    fn add_summary(&mut self, summary: &'a FoldSummary, _: &MultiBufferSnapshot) {
1326        *self += summary.count;
1327    }
1328}
1329
1330#[derive(Clone)]
1331pub struct FoldRows<'a> {
1332    cursor: Cursor<'a, 'static, Transform, Dimensions<FoldPoint, InlayPoint>>,
1333    input_rows: InlayBufferRows<'a>,
1334    fold_point: FoldPoint,
1335}
1336
1337impl FoldRows<'_> {
1338    #[ztracing::instrument(skip_all)]
1339    pub(crate) fn seek(&mut self, row: u32) {
1340        let fold_point = FoldPoint::new(row, 0);
1341        self.cursor.seek(&fold_point, Bias::Left);
1342        let overshoot = fold_point.0 - self.cursor.start().0.0;
1343        let inlay_point = InlayPoint(self.cursor.start().1.0 + overshoot);
1344        self.input_rows.seek(inlay_point.row());
1345        self.fold_point = fold_point;
1346    }
1347}
1348
1349impl Iterator for FoldRows<'_> {
1350    type Item = RowInfo;
1351
1352    #[ztracing::instrument(skip_all)]
1353    fn next(&mut self) -> Option<Self::Item> {
1354        let mut traversed_fold = false;
1355        while self.fold_point > self.cursor.end().0 {
1356            self.cursor.next();
1357            traversed_fold = true;
1358            if self.cursor.item().is_none() {
1359                break;
1360            }
1361        }
1362
1363        if self.cursor.item().is_some() {
1364            if traversed_fold {
1365                self.input_rows.seek(self.cursor.start().1.0.row);
1366                self.input_rows.next();
1367            }
1368            *self.fold_point.row_mut() += 1;
1369            self.input_rows.next()
1370        } else {
1371            None
1372        }
1373    }
1374}
1375
1376/// A chunk of a buffer's text, along with its syntax highlight and
1377/// diagnostic status.
1378#[derive(Clone, Debug, Default)]
1379pub struct Chunk<'a> {
1380    /// The text of the chunk.
1381    pub text: &'a str,
1382    /// The syntax highlighting style of the chunk.
1383    pub syntax_highlight_id: Option<HighlightId>,
1384    /// The highlight style that has been applied to this chunk in
1385    /// the editor.
1386    pub highlight_style: Option<HighlightStyle>,
1387    /// The severity of diagnostic associated with this chunk, if any.
1388    pub diagnostic_severity: Option<lsp::DiagnosticSeverity>,
1389    /// Whether this chunk of text is marked as unnecessary.
1390    pub is_unnecessary: bool,
1391    /// Whether this chunk of text should be underlined.
1392    pub underline: bool,
1393    /// Whether this chunk of text was originally a tab character.
1394    pub is_tab: bool,
1395    /// Whether this chunk of text was originally a tab character.
1396    pub is_inlay: bool,
1397    /// An optional recipe for how the chunk should be presented.
1398    pub renderer: Option<ChunkRenderer>,
1399    /// Bitmap of tab character locations in chunk
1400    pub tabs: u128,
1401    /// Bitmap of character locations in chunk
1402    pub chars: u128,
1403    /// Bitmap of newline locations in chunk
1404    pub newlines: u128,
1405}
1406
1407#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
1408pub enum ChunkRendererId {
1409    Fold(FoldId),
1410    Inlay(InlayId),
1411}
1412
1413/// A recipe for how the chunk should be presented.
1414#[derive(Clone)]
1415pub struct ChunkRenderer {
1416    /// The id of the renderer associated with this chunk.
1417    pub id: ChunkRendererId,
1418    /// Creates a custom element to represent this chunk.
1419    pub render: Arc<dyn Send + Sync + Fn(&mut ChunkRendererContext) -> AnyElement>,
1420    /// If true, the element is constrained to the shaped width of the text.
1421    pub constrain_width: bool,
1422    /// The width of the element, as measured during the last layout pass.
1423    ///
1424    /// This is None if the element has not been laid out yet.
1425    pub measured_width: Option<Pixels>,
1426}
1427
1428pub struct ChunkRendererContext<'a, 'b> {
1429    pub window: &'a mut Window,
1430    pub context: &'b mut App,
1431    pub max_width: Pixels,
1432}
1433
1434impl fmt::Debug for ChunkRenderer {
1435    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1436        f.debug_struct("ChunkRenderer")
1437            .field("constrain_width", &self.constrain_width)
1438            .finish()
1439    }
1440}
1441
1442impl Deref for ChunkRendererContext<'_, '_> {
1443    type Target = App;
1444
1445    fn deref(&self) -> &Self::Target {
1446        self.context
1447    }
1448}
1449
1450impl DerefMut for ChunkRendererContext<'_, '_> {
1451    fn deref_mut(&mut self) -> &mut Self::Target {
1452        self.context
1453    }
1454}
1455
1456pub struct FoldChunks<'a> {
1457    transform_cursor: Cursor<'a, 'static, Transform, Dimensions<FoldOffset, InlayOffset>>,
1458    inlay_chunks: InlayChunks<'a>,
1459    inlay_chunk: Option<(InlayOffset, InlayChunk<'a>)>,
1460    inlay_offset: InlayOffset,
1461    output_offset: FoldOffset,
1462    max_output_offset: FoldOffset,
1463}
1464
1465impl FoldChunks<'_> {
1466    #[ztracing::instrument(skip_all)]
1467    pub(crate) fn seek(&mut self, range: Range<FoldOffset>) {
1468        self.transform_cursor.seek(&range.start, Bias::Right);
1469
1470        let inlay_start = {
1471            let overshoot = range.start - self.transform_cursor.start().0;
1472            self.transform_cursor.start().1 + overshoot
1473        };
1474
1475        let transform_end = self.transform_cursor.end();
1476
1477        let inlay_end = if self
1478            .transform_cursor
1479            .item()
1480            .is_none_or(|transform| transform.is_fold())
1481        {
1482            inlay_start
1483        } else if range.end < transform_end.0 {
1484            let overshoot = range.end - self.transform_cursor.start().0;
1485            self.transform_cursor.start().1 + overshoot
1486        } else {
1487            transform_end.1
1488        };
1489
1490        self.inlay_chunks.seek(inlay_start..inlay_end);
1491        self.inlay_chunk = None;
1492        self.inlay_offset = inlay_start;
1493        self.output_offset = range.start;
1494        self.max_output_offset = range.end;
1495    }
1496}
1497
1498impl<'a> Iterator for FoldChunks<'a> {
1499    type Item = Chunk<'a>;
1500
1501    #[ztracing::instrument(skip_all)]
1502    fn next(&mut self) -> Option<Self::Item> {
1503        if self.output_offset >= self.max_output_offset {
1504            return None;
1505        }
1506
1507        let transform = self.transform_cursor.item()?;
1508
1509        // If we're in a fold, then return the fold's display text and
1510        // advance the transform and buffer cursors to the end of the fold.
1511        if let Some(placeholder) = transform.placeholder.as_ref() {
1512            self.inlay_chunk.take();
1513            self.inlay_offset += InlayOffset(transform.summary.input.len);
1514
1515            while self.inlay_offset >= self.transform_cursor.end().1
1516                && self.transform_cursor.item().is_some()
1517            {
1518                self.transform_cursor.next();
1519            }
1520
1521            self.output_offset.0 += placeholder.text.len();
1522            return Some(Chunk {
1523                text: &placeholder.text,
1524                chars: placeholder.chars,
1525                renderer: Some(placeholder.renderer.clone()),
1526                ..Default::default()
1527            });
1528        }
1529
1530        // When we reach a non-fold region, seek the underlying text
1531        // chunk iterator to the next unfolded range.
1532        if self.inlay_offset == self.transform_cursor.start().1
1533            && self.inlay_chunks.offset() != self.inlay_offset
1534        {
1535            let transform_start = self.transform_cursor.start();
1536            let transform_end = self.transform_cursor.end();
1537            let inlay_end = if self.max_output_offset < transform_end.0 {
1538                let overshoot = self.max_output_offset - transform_start.0;
1539                transform_start.1 + overshoot
1540            } else {
1541                transform_end.1
1542            };
1543
1544            self.inlay_chunks.seek(self.inlay_offset..inlay_end);
1545        }
1546
1547        // Retrieve a chunk from the current location in the buffer.
1548        if self.inlay_chunk.is_none() {
1549            let chunk_offset = self.inlay_chunks.offset();
1550            self.inlay_chunk = self.inlay_chunks.next().map(|chunk| (chunk_offset, chunk));
1551        }
1552
1553        // Otherwise, take a chunk from the buffer's text.
1554        if let Some((buffer_chunk_start, mut inlay_chunk)) = self.inlay_chunk.clone() {
1555            let chunk = &mut inlay_chunk.chunk;
1556            let buffer_chunk_end = buffer_chunk_start + chunk.text.len();
1557            let transform_end = self.transform_cursor.end().1;
1558            let chunk_end = buffer_chunk_end.min(transform_end);
1559
1560            let bit_start = self.inlay_offset - buffer_chunk_start;
1561            let bit_end = chunk_end - buffer_chunk_start;
1562            chunk.text = &chunk.text[bit_start..bit_end];
1563
1564            let bit_end = chunk_end - buffer_chunk_start;
1565            let mask = 1u128.unbounded_shl(bit_end as u32).wrapping_sub(1);
1566
1567            chunk.tabs = (chunk.tabs >> bit_start) & mask;
1568            chunk.chars = (chunk.chars >> bit_start) & mask;
1569            chunk.newlines = (chunk.newlines >> bit_start) & mask;
1570
1571            if chunk_end == transform_end {
1572                self.transform_cursor.next();
1573            } else if chunk_end == buffer_chunk_end {
1574                self.inlay_chunk.take();
1575            }
1576
1577            self.inlay_offset = chunk_end;
1578            self.output_offset.0 += chunk.text.len();
1579            return Some(Chunk {
1580                text: chunk.text,
1581                tabs: chunk.tabs,
1582                chars: chunk.chars,
1583                newlines: chunk.newlines,
1584                syntax_highlight_id: chunk.syntax_highlight_id,
1585                highlight_style: chunk.highlight_style,
1586                diagnostic_severity: chunk.diagnostic_severity,
1587                is_unnecessary: chunk.is_unnecessary,
1588                is_tab: chunk.is_tab,
1589                is_inlay: chunk.is_inlay,
1590                underline: chunk.underline,
1591                renderer: inlay_chunk.renderer,
1592            });
1593        }
1594
1595        None
1596    }
1597}
1598
1599#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1600pub struct FoldOffset(pub MultiBufferOffset);
1601
1602impl FoldOffset {
1603    #[ztracing::instrument(skip_all)]
1604    pub fn to_point(self, snapshot: &FoldSnapshot) -> FoldPoint {
1605        let (start, _, item) = snapshot
1606            .transforms
1607            .find::<Dimensions<FoldOffset, TransformSummary>, _>((), &self, Bias::Right);
1608        let overshoot = if item.is_none_or(|t| t.is_fold()) {
1609            Point::new(0, (self.0 - start.0.0) as u32)
1610        } else {
1611            let inlay_offset = start.1.input.len + (self - start.0);
1612            let inlay_point = snapshot.inlay_snapshot.to_point(InlayOffset(inlay_offset));
1613            inlay_point.0 - start.1.input.lines
1614        };
1615        FoldPoint(start.1.output.lines + overshoot)
1616    }
1617
1618    #[cfg(test)]
1619    #[ztracing::instrument(skip_all)]
1620    pub fn to_inlay_offset(self, snapshot: &FoldSnapshot) -> InlayOffset {
1621        let (start, _, _) = snapshot
1622            .transforms
1623            .find::<Dimensions<FoldOffset, InlayOffset>, _>((), &self, Bias::Right);
1624        let overshoot = self - start.0;
1625        InlayOffset(start.1.0 + overshoot)
1626    }
1627}
1628
1629impl Add for FoldOffset {
1630    type Output = Self;
1631
1632    fn add(self, rhs: Self) -> Self::Output {
1633        Self(self.0 + rhs.0)
1634    }
1635}
1636
1637impl Sub for FoldOffset {
1638    type Output = <MultiBufferOffset as Sub>::Output;
1639
1640    fn sub(self, rhs: Self) -> Self::Output {
1641        self.0 - rhs.0
1642    }
1643}
1644
1645impl<T> SubAssign<T> for FoldOffset
1646where
1647    MultiBufferOffset: SubAssign<T>,
1648{
1649    fn sub_assign(&mut self, rhs: T) {
1650        self.0 -= rhs;
1651    }
1652}
1653
1654impl<T> Add<T> for FoldOffset
1655where
1656    MultiBufferOffset: Add<T, Output = MultiBufferOffset>,
1657{
1658    type Output = Self;
1659
1660    fn add(self, rhs: T) -> Self::Output {
1661        Self(self.0 + rhs)
1662    }
1663}
1664
1665impl AddAssign for FoldOffset {
1666    fn add_assign(&mut self, rhs: Self) {
1667        self.0 += rhs.0;
1668    }
1669}
1670
1671impl<T> AddAssign<T> for FoldOffset
1672where
1673    MultiBufferOffset: AddAssign<T>,
1674{
1675    fn add_assign(&mut self, rhs: T) {
1676        self.0 += rhs;
1677    }
1678}
1679
1680impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1681    fn zero(_cx: ()) -> Self {
1682        Default::default()
1683    }
1684
1685    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1686        self.0 += summary.output.len;
1687    }
1688}
1689
1690impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayPoint {
1691    fn zero(_cx: ()) -> Self {
1692        Default::default()
1693    }
1694
1695    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1696        self.0 += &summary.input.lines;
1697    }
1698}
1699
1700impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayOffset {
1701    fn zero(_cx: ()) -> Self {
1702        Default::default()
1703    }
1704
1705    fn add_summary(&mut self, summary: &'a TransformSummary, _: ()) {
1706        self.0 += summary.input.len;
1707    }
1708}
1709
1710pub type FoldEdit = Edit<FoldOffset>;
1711
1712#[cfg(test)]
1713mod tests {
1714    use super::*;
1715    use crate::{MultiBuffer, ToPoint, display_map::inlay_map::InlayMap};
1716    use Bias::{Left, Right};
1717    use collections::HashSet;
1718    use rand::prelude::*;
1719    use settings::SettingsStore;
1720    use std::{env, mem};
1721    use text::Patch;
1722    use util::RandomCharIter;
1723    use util::test::sample_text;
1724
1725    #[gpui::test]
1726    fn test_basic_folds(cx: &mut gpui::App) {
1727        init_test(cx);
1728        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1729        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1730        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1731        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1732        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1733
1734        let (mut writer, _, _) = map.write(inlay_snapshot, vec![]);
1735        let (snapshot2, edits) = writer.fold(vec![
1736            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1737            (Point::new(2, 4)..Point::new(4, 1), FoldPlaceholder::test()),
1738        ]);
1739        assert_eq!(snapshot2.text(), "aa⋯cc⋯eeeee");
1740        assert_eq!(
1741            edits,
1742            &[
1743                FoldEdit {
1744                    old: FoldOffset(MultiBufferOffset(2))..FoldOffset(MultiBufferOffset(16)),
1745                    new: FoldOffset(MultiBufferOffset(2))..FoldOffset(MultiBufferOffset(5)),
1746                },
1747                FoldEdit {
1748                    old: FoldOffset(MultiBufferOffset(18))..FoldOffset(MultiBufferOffset(29)),
1749                    new: FoldOffset(MultiBufferOffset(7))..FoldOffset(MultiBufferOffset(10)),
1750                },
1751            ]
1752        );
1753
1754        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1755            buffer.edit(
1756                vec![
1757                    (Point::new(0, 0)..Point::new(0, 1), "123"),
1758                    (Point::new(2, 3)..Point::new(2, 3), "123"),
1759                ],
1760                None,
1761                cx,
1762            );
1763            buffer.snapshot(cx)
1764        });
1765
1766        let (inlay_snapshot, inlay_edits) =
1767            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1768        let (snapshot3, edits) = map.read(inlay_snapshot, inlay_edits);
1769        assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
1770        assert_eq!(
1771            edits,
1772            &[
1773                FoldEdit {
1774                    old: FoldOffset(MultiBufferOffset(0))..FoldOffset(MultiBufferOffset(1)),
1775                    new: FoldOffset(MultiBufferOffset(0))..FoldOffset(MultiBufferOffset(3)),
1776                },
1777                FoldEdit {
1778                    old: FoldOffset(MultiBufferOffset(6))..FoldOffset(MultiBufferOffset(6)),
1779                    new: FoldOffset(MultiBufferOffset(8))..FoldOffset(MultiBufferOffset(11)),
1780                },
1781            ]
1782        );
1783
1784        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1785            buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
1786            buffer.snapshot(cx)
1787        });
1788        let (inlay_snapshot, inlay_edits) =
1789            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1790        let (snapshot4, _) = map.read(inlay_snapshot.clone(), inlay_edits);
1791        assert_eq!(snapshot4.text(), "123a⋯c123456eee");
1792
1793        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1794        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), false);
1795        let (snapshot5, _) = map.read(inlay_snapshot.clone(), vec![]);
1796        assert_eq!(snapshot5.text(), "123a⋯c123456eee");
1797
1798        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1799        writer.unfold_intersecting(Some(Point::new(0, 4)..Point::new(0, 4)), true);
1800        let (snapshot6, _) = map.read(inlay_snapshot, vec![]);
1801        assert_eq!(snapshot6.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1802    }
1803
1804    #[gpui::test]
1805    fn test_adjacent_folds(cx: &mut gpui::App) {
1806        init_test(cx);
1807        let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
1808        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1809        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1810        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1811
1812        {
1813            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1814
1815            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1816            writer.fold(vec![(
1817                MultiBufferOffset(5)..MultiBufferOffset(8),
1818                FoldPlaceholder::test(),
1819            )]);
1820            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1821            assert_eq!(snapshot.text(), "abcde⋯ijkl");
1822
1823            // Create an fold adjacent to the start of the first fold.
1824            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1825            writer.fold(vec![
1826                (
1827                    MultiBufferOffset(0)..MultiBufferOffset(1),
1828                    FoldPlaceholder::test(),
1829                ),
1830                (
1831                    MultiBufferOffset(2)..MultiBufferOffset(5),
1832                    FoldPlaceholder::test(),
1833                ),
1834            ]);
1835            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1836            assert_eq!(snapshot.text(), "⋯b⋯ijkl");
1837
1838            // Create an fold adjacent to the end of the first fold.
1839            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1840            writer.fold(vec![
1841                (
1842                    MultiBufferOffset(11)..MultiBufferOffset(11),
1843                    FoldPlaceholder::test(),
1844                ),
1845                (
1846                    MultiBufferOffset(8)..MultiBufferOffset(10),
1847                    FoldPlaceholder::test(),
1848                ),
1849            ]);
1850            let (snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
1851            assert_eq!(snapshot.text(), "⋯b⋯kl");
1852        }
1853
1854        {
1855            let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1856
1857            // Create two adjacent folds.
1858            let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1859            writer.fold(vec![
1860                (
1861                    MultiBufferOffset(0)..MultiBufferOffset(2),
1862                    FoldPlaceholder::test(),
1863                ),
1864                (
1865                    MultiBufferOffset(2)..MultiBufferOffset(5),
1866                    FoldPlaceholder::test(),
1867                ),
1868            ]);
1869            let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1870            assert_eq!(snapshot.text(), "⋯fghijkl");
1871
1872            // Edit within one of the folds.
1873            let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1874                buffer.edit(
1875                    [(MultiBufferOffset(0)..MultiBufferOffset(1), "12345")],
1876                    None,
1877                    cx,
1878                );
1879                buffer.snapshot(cx)
1880            });
1881            let (inlay_snapshot, inlay_edits) =
1882                inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1883            let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1884            assert_eq!(snapshot.text(), "12345⋯fghijkl");
1885        }
1886    }
1887
1888    #[gpui::test]
1889    fn test_overlapping_folds(cx: &mut gpui::App) {
1890        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1891        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1892        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1893        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1894        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1895        writer.fold(vec![
1896            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1897            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1898            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1899            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1900        ]);
1901        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1902        assert_eq!(snapshot.text(), "aa⋯eeeee");
1903    }
1904
1905    #[gpui::test]
1906    fn test_merging_folds_via_edit(cx: &mut gpui::App) {
1907        init_test(cx);
1908        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1909        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1910        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1911        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot);
1912        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1913
1914        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1915        writer.fold(vec![
1916            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1917            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1918        ]);
1919        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1920        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee");
1921
1922        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1923            buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
1924            buffer.snapshot(cx)
1925        });
1926        let (inlay_snapshot, inlay_edits) =
1927            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1928        let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
1929        assert_eq!(snapshot.text(), "aa⋯eeeee");
1930    }
1931
1932    #[gpui::test]
1933    fn test_folds_in_range(cx: &mut gpui::App) {
1934        let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
1935        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1936        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1937        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1938
1939        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
1940        writer.fold(vec![
1941            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
1942            (Point::new(0, 4)..Point::new(1, 0), FoldPlaceholder::test()),
1943            (Point::new(1, 2)..Point::new(3, 2), FoldPlaceholder::test()),
1944            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
1945        ]);
1946        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
1947        let fold_ranges = snapshot
1948            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1949            .map(|fold| {
1950                fold.range.start.to_point(&buffer_snapshot)
1951                    ..fold.range.end.to_point(&buffer_snapshot)
1952            })
1953            .collect::<Vec<_>>();
1954        assert_eq!(
1955            fold_ranges,
1956            vec![
1957                Point::new(0, 2)..Point::new(2, 2),
1958                Point::new(1, 2)..Point::new(3, 2)
1959            ]
1960        );
1961    }
1962
1963    #[gpui::test(iterations = 100)]
1964    fn test_random_folds(cx: &mut gpui::App, mut rng: StdRng) {
1965        init_test(cx);
1966        let operations = env::var("OPERATIONS")
1967            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1968            .unwrap_or(10);
1969
1970        let len = rng.random_range(0..10);
1971        let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1972        let buffer = if rng.random() {
1973            MultiBuffer::build_simple(&text, cx)
1974        } else {
1975            MultiBuffer::build_random(&mut rng, cx)
1976        };
1977        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1978        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1979        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
1980
1981        let (mut initial_snapshot, _) = map.read(inlay_snapshot, vec![]);
1982        let mut snapshot_edits = Vec::new();
1983
1984        let mut next_inlay_id = 0;
1985        for _ in 0..operations {
1986            log::info!("text: {:?}", buffer_snapshot.text());
1987            let mut buffer_edits = Vec::new();
1988            let mut inlay_edits = Vec::new();
1989            match rng.random_range(0..=100) {
1990                0..=39 => {
1991                    snapshot_edits.extend(map.randomly_mutate(&mut rng));
1992                }
1993                40..=59 => {
1994                    let (_, edits) = inlay_map.randomly_mutate(&mut next_inlay_id, &mut rng);
1995                    inlay_edits = edits;
1996                }
1997                _ => buffer.update(cx, |buffer, cx| {
1998                    let subscription = buffer.subscribe();
1999                    let edit_count = rng.random_range(1..=5);
2000                    buffer.randomly_mutate(&mut rng, edit_count, cx);
2001                    buffer_snapshot = buffer.snapshot(cx);
2002                    let edits = subscription.consume().into_inner();
2003                    log::info!("editing {:?}", edits);
2004                    buffer_edits.extend(edits);
2005                }),
2006            };
2007
2008            let (inlay_snapshot, new_inlay_edits) =
2009                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
2010            log::info!("inlay text {:?}", inlay_snapshot.text());
2011
2012            let inlay_edits = Patch::new(inlay_edits)
2013                .compose(new_inlay_edits)
2014                .into_inner();
2015            let (snapshot, edits) = map.read(inlay_snapshot.clone(), inlay_edits);
2016            snapshot_edits.push((snapshot.clone(), edits));
2017
2018            let mut expected_text: String = inlay_snapshot.text().to_string();
2019            for fold_range in map.merged_folds().into_iter().rev() {
2020                let fold_inlay_start = inlay_snapshot.to_inlay_offset(fold_range.start);
2021                let fold_inlay_end = inlay_snapshot.to_inlay_offset(fold_range.end);
2022                expected_text.replace_range(fold_inlay_start.0.0..fold_inlay_end.0.0, "");
2023            }
2024
2025            assert_eq!(snapshot.text(), expected_text);
2026            log::info!(
2027                "fold text {:?} ({} lines)",
2028                expected_text,
2029                expected_text.matches('\n').count() + 1
2030            );
2031
2032            let mut prev_row = 0;
2033            let mut expected_buffer_rows = Vec::new();
2034            for fold_range in map.merged_folds() {
2035                let fold_start = inlay_snapshot
2036                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.start))
2037                    .row();
2038                let fold_end = inlay_snapshot
2039                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.end))
2040                    .row();
2041                expected_buffer_rows.extend(
2042                    inlay_snapshot
2043                        .row_infos(prev_row)
2044                        .take((1 + fold_start - prev_row) as usize),
2045                );
2046                prev_row = 1 + fold_end;
2047            }
2048            expected_buffer_rows.extend(inlay_snapshot.row_infos(prev_row));
2049
2050            assert_eq!(
2051                expected_buffer_rows.len(),
2052                expected_text.matches('\n').count() + 1,
2053                "wrong expected buffer rows {:?}. text: {:?}",
2054                expected_buffer_rows,
2055                expected_text
2056            );
2057
2058            for (output_row, line) in expected_text.lines().enumerate() {
2059                let line_len = snapshot.line_len(output_row as u32);
2060                assert_eq!(line_len, line.len() as u32);
2061            }
2062
2063            let longest_row = snapshot.longest_row();
2064            let longest_char_column = expected_text
2065                .split('\n')
2066                .nth(longest_row as usize)
2067                .unwrap()
2068                .chars()
2069                .count();
2070            let mut fold_point = FoldPoint::new(0, 0);
2071            let mut fold_offset = FoldOffset(MultiBufferOffset(0));
2072            let mut char_column = 0;
2073            for c in expected_text.chars() {
2074                let inlay_point = fold_point.to_inlay_point(&snapshot);
2075                let inlay_offset = fold_offset.to_inlay_offset(&snapshot);
2076                assert_eq!(
2077                    snapshot.to_fold_point(inlay_point, Right),
2078                    fold_point,
2079                    "{:?} -> fold point",
2080                    inlay_point,
2081                );
2082                assert_eq!(
2083                    inlay_snapshot.to_offset(inlay_point),
2084                    inlay_offset,
2085                    "inlay_snapshot.to_offset({:?})",
2086                    inlay_point,
2087                );
2088                assert_eq!(
2089                    fold_point.to_offset(&snapshot),
2090                    fold_offset,
2091                    "fold_point.to_offset({:?})",
2092                    fold_point,
2093                );
2094
2095                if c == '\n' {
2096                    *fold_point.row_mut() += 1;
2097                    *fold_point.column_mut() = 0;
2098                    char_column = 0;
2099                } else {
2100                    *fold_point.column_mut() += c.len_utf8() as u32;
2101                    char_column += 1;
2102                }
2103                fold_offset.0 += c.len_utf8();
2104                if char_column > longest_char_column {
2105                    panic!(
2106                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
2107                        longest_row,
2108                        longest_char_column,
2109                        fold_point.row(),
2110                        char_column
2111                    );
2112                }
2113            }
2114
2115            for _ in 0..5 {
2116                let mut start = snapshot.clip_offset(
2117                    FoldOffset(rng.random_range(MultiBufferOffset(0)..=snapshot.len().0)),
2118                    Bias::Left,
2119                );
2120                let mut end = snapshot.clip_offset(
2121                    FoldOffset(rng.random_range(MultiBufferOffset(0)..=snapshot.len().0)),
2122                    Bias::Right,
2123                );
2124                if start > end {
2125                    mem::swap(&mut start, &mut end);
2126                }
2127
2128                let text = &expected_text[start.0.0..end.0.0];
2129                assert_eq!(
2130                    snapshot
2131                        .chunks(start..end, false, Highlights::default())
2132                        .map(|c| c.text)
2133                        .collect::<String>(),
2134                    text,
2135                );
2136            }
2137
2138            let mut fold_row = 0;
2139            while fold_row < expected_buffer_rows.len() as u32 {
2140                assert_eq!(
2141                    snapshot.row_infos(fold_row).collect::<Vec<_>>(),
2142                    expected_buffer_rows[(fold_row as usize)..],
2143                    "wrong buffer rows starting at fold row {}",
2144                    fold_row,
2145                );
2146                fold_row += 1;
2147            }
2148
2149            let folded_buffer_rows = map
2150                .merged_folds()
2151                .iter()
2152                .flat_map(|fold_range| {
2153                    let start_row = fold_range.start.to_point(&buffer_snapshot).row;
2154                    let end = fold_range.end.to_point(&buffer_snapshot);
2155                    if end.column == 0 {
2156                        start_row..end.row
2157                    } else {
2158                        start_row..end.row + 1
2159                    }
2160                })
2161                .collect::<HashSet<_>>();
2162            for row in 0..=buffer_snapshot.max_point().row {
2163                assert_eq!(
2164                    snapshot.is_line_folded(MultiBufferRow(row)),
2165                    folded_buffer_rows.contains(&row),
2166                    "expected buffer row {}{} to be folded",
2167                    row,
2168                    if folded_buffer_rows.contains(&row) {
2169                        ""
2170                    } else {
2171                        " not"
2172                    }
2173                );
2174            }
2175
2176            for _ in 0..5 {
2177                let end = buffer_snapshot.clip_offset(
2178                    rng.random_range(MultiBufferOffset(0)..=buffer_snapshot.len()),
2179                    Right,
2180                );
2181                let start =
2182                    buffer_snapshot.clip_offset(rng.random_range(MultiBufferOffset(0)..=end), Left);
2183                let expected_folds = map
2184                    .snapshot
2185                    .folds
2186                    .items(&buffer_snapshot)
2187                    .into_iter()
2188                    .filter(|fold| {
2189                        let start = buffer_snapshot.anchor_before(start);
2190                        let end = buffer_snapshot.anchor_after(end);
2191                        start.cmp(&fold.range.end, &buffer_snapshot) == Ordering::Less
2192                            && end.cmp(&fold.range.start, &buffer_snapshot) == Ordering::Greater
2193                    })
2194                    .collect::<Vec<_>>();
2195
2196                assert_eq!(
2197                    snapshot
2198                        .folds_in_range(start..end)
2199                        .cloned()
2200                        .collect::<Vec<_>>(),
2201                    expected_folds
2202                );
2203            }
2204
2205            let text = snapshot.text();
2206            for _ in 0..5 {
2207                let start_row = rng.random_range(0..=snapshot.max_point().row());
2208                let start_column = rng.random_range(0..=snapshot.line_len(start_row));
2209                let end_row = rng.random_range(0..=snapshot.max_point().row());
2210                let end_column = rng.random_range(0..=snapshot.line_len(end_row));
2211                let mut start =
2212                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
2213                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
2214                if start > end {
2215                    mem::swap(&mut start, &mut end);
2216                }
2217
2218                let lines = start..end;
2219                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
2220                assert_eq!(
2221                    snapshot.text_summary_for_range(lines),
2222                    MBTextSummary::from(&text[bytes.start.0.0..bytes.end.0.0])
2223                )
2224            }
2225
2226            let mut text = initial_snapshot.text();
2227            for (snapshot, edits) in snapshot_edits.drain(..) {
2228                let new_text = snapshot.text();
2229                for edit in edits {
2230                    let old_bytes = edit.new.start.0.0..edit.new.start.0.0 + edit.old_len();
2231                    let new_bytes = edit.new.start.0.0..edit.new.end.0.0;
2232                    text.replace_range(old_bytes, &new_text[new_bytes]);
2233                }
2234
2235                assert_eq!(text, new_text);
2236                initial_snapshot = snapshot;
2237            }
2238        }
2239    }
2240
2241    #[gpui::test]
2242    fn test_buffer_rows(cx: &mut gpui::App) {
2243        let text = sample_text(6, 6, 'a') + "\n";
2244        let buffer = MultiBuffer::build_simple(&text, cx);
2245
2246        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2247        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
2248        let mut map = FoldMap::new(inlay_snapshot.clone()).0;
2249
2250        let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
2251        writer.fold(vec![
2252            (Point::new(0, 2)..Point::new(2, 2), FoldPlaceholder::test()),
2253            (Point::new(3, 1)..Point::new(4, 1), FoldPlaceholder::test()),
2254        ]);
2255
2256        let (snapshot, _) = map.read(inlay_snapshot, vec![]);
2257        assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
2258        assert_eq!(
2259            snapshot
2260                .row_infos(0)
2261                .map(|info| info.buffer_row)
2262                .collect::<Vec<_>>(),
2263            [Some(0), Some(3), Some(5), Some(6)]
2264        );
2265        assert_eq!(
2266            snapshot
2267                .row_infos(3)
2268                .map(|info| info.buffer_row)
2269                .collect::<Vec<_>>(),
2270            [Some(6)]
2271        );
2272    }
2273
2274    #[gpui::test(iterations = 100)]
2275    fn test_random_chunk_bitmaps(cx: &mut gpui::App, mut rng: StdRng) {
2276        init_test(cx);
2277
2278        // Generate random buffer using existing test infrastructure
2279        let text_len = rng.random_range(0..10000);
2280        let buffer = if rng.random() {
2281            let text = RandomCharIter::new(&mut rng)
2282                .take(text_len)
2283                .collect::<String>();
2284            MultiBuffer::build_simple(&text, cx)
2285        } else {
2286            MultiBuffer::build_random(&mut rng, cx)
2287        };
2288        let buffer_snapshot = buffer.read(cx).snapshot(cx);
2289        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
2290        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
2291
2292        // Perform random mutations
2293        let mutation_count = rng.random_range(1..10);
2294        for _ in 0..mutation_count {
2295            fold_map.randomly_mutate(&mut rng);
2296        }
2297
2298        let (snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
2299
2300        // Get all chunks and verify their bitmaps
2301        let chunks = snapshot.chunks(
2302            FoldOffset(MultiBufferOffset(0))..FoldOffset(snapshot.len().0),
2303            false,
2304            Highlights::default(),
2305        );
2306
2307        for chunk in chunks {
2308            let chunk_text = chunk.text;
2309            let chars_bitmap = chunk.chars;
2310            let tabs_bitmap = chunk.tabs;
2311
2312            // Check empty chunks have empty bitmaps
2313            if chunk_text.is_empty() {
2314                assert_eq!(
2315                    chars_bitmap, 0,
2316                    "Empty chunk should have empty chars bitmap"
2317                );
2318                assert_eq!(tabs_bitmap, 0, "Empty chunk should have empty tabs bitmap");
2319                continue;
2320            }
2321
2322            // Verify that chunk text doesn't exceed 128 bytes
2323            assert!(
2324                chunk_text.len() <= 128,
2325                "Chunk text length {} exceeds 128 bytes",
2326                chunk_text.len()
2327            );
2328
2329            // Verify chars bitmap
2330            let char_indices = chunk_text
2331                .char_indices()
2332                .map(|(i, _)| i)
2333                .collect::<Vec<_>>();
2334
2335            for byte_idx in 0..chunk_text.len() {
2336                let should_have_bit = char_indices.contains(&byte_idx);
2337                let has_bit = chars_bitmap & (1 << byte_idx) != 0;
2338
2339                if has_bit != should_have_bit {
2340                    eprintln!("Chunk text bytes: {:?}", chunk_text.as_bytes());
2341                    eprintln!("Char indices: {:?}", char_indices);
2342                    eprintln!("Chars bitmap: {:#b}", chars_bitmap);
2343                    assert_eq!(
2344                        has_bit, should_have_bit,
2345                        "Chars bitmap mismatch at byte index {} in chunk {:?}. Expected bit: {}, Got bit: {}",
2346                        byte_idx, chunk_text, should_have_bit, has_bit
2347                    );
2348                }
2349            }
2350
2351            // Verify tabs bitmap
2352            for (byte_idx, byte) in chunk_text.bytes().enumerate() {
2353                let is_tab = byte == b'\t';
2354                let has_bit = tabs_bitmap & (1 << byte_idx) != 0;
2355
2356                assert_eq!(
2357                    has_bit, is_tab,
2358                    "Tabs bitmap mismatch at byte index {} in chunk {:?}. Byte: {:?}, Expected bit: {}, Got bit: {}",
2359                    byte_idx, chunk_text, byte as char, is_tab, has_bit
2360                );
2361            }
2362        }
2363    }
2364
2365    fn init_test(cx: &mut gpui::App) {
2366        let store = SettingsStore::test(cx);
2367        cx.set_global(store);
2368    }
2369
2370    impl FoldMap {
2371        fn merged_folds(&self) -> Vec<Range<MultiBufferOffset>> {
2372            let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2373            let buffer = &inlay_snapshot.buffer;
2374            let mut folds = self.snapshot.folds.items(buffer);
2375            // Ensure sorting doesn't change how folds get merged and displayed.
2376            folds.sort_by(|a, b| a.range.cmp(&b.range, buffer));
2377            let mut folds = folds
2378                .iter()
2379                .map(|fold| fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer))
2380                .peekable();
2381
2382            let mut merged_folds = Vec::new();
2383            while let Some(mut fold_range) = folds.next() {
2384                while let Some(next_range) = folds.peek() {
2385                    if fold_range.end >= next_range.start {
2386                        if next_range.end > fold_range.end {
2387                            fold_range.end = next_range.end;
2388                        }
2389                        folds.next();
2390                    } else {
2391                        break;
2392                    }
2393                }
2394                if fold_range.end > fold_range.start {
2395                    merged_folds.push(fold_range);
2396                }
2397            }
2398            merged_folds
2399        }
2400
2401        pub fn randomly_mutate(
2402            &mut self,
2403            rng: &mut impl Rng,
2404        ) -> Vec<(FoldSnapshot, Vec<FoldEdit>)> {
2405            let mut snapshot_edits = Vec::new();
2406            match rng.random_range(0..=100) {
2407                0..=39 if !self.snapshot.folds.is_empty() => {
2408                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2409                    let buffer = &inlay_snapshot.buffer;
2410                    let mut to_unfold = Vec::new();
2411                    for _ in 0..rng.random_range(1..=3) {
2412                        let end = buffer.clip_offset(
2413                            rng.random_range(MultiBufferOffset(0)..=buffer.len()),
2414                            Right,
2415                        );
2416                        let start =
2417                            buffer.clip_offset(rng.random_range(MultiBufferOffset(0)..=end), Left);
2418                        to_unfold.push(start..end);
2419                    }
2420                    let inclusive = rng.random();
2421                    log::info!("unfolding {:?} (inclusive: {})", to_unfold, inclusive);
2422                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2423                    snapshot_edits.push((snapshot, edits));
2424                    let (snapshot, edits) = writer.unfold_intersecting(to_unfold, inclusive);
2425                    snapshot_edits.push((snapshot, edits));
2426                }
2427                _ => {
2428                    let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
2429                    let buffer = &inlay_snapshot.buffer;
2430                    let mut to_fold = Vec::new();
2431                    for _ in 0..rng.random_range(1..=2) {
2432                        let end = buffer.clip_offset(
2433                            rng.random_range(MultiBufferOffset(0)..=buffer.len()),
2434                            Right,
2435                        );
2436                        let start =
2437                            buffer.clip_offset(rng.random_range(MultiBufferOffset(0)..=end), Left);
2438                        to_fold.push((start..end, FoldPlaceholder::test()));
2439                    }
2440                    log::info!("folding {:?}", to_fold);
2441                    let (mut writer, snapshot, edits) = self.write(inlay_snapshot, vec![]);
2442                    snapshot_edits.push((snapshot, edits));
2443                    let (snapshot, edits) = writer.fold(to_fold);
2444                    snapshot_edits.push((snapshot, edits));
2445                }
2446            }
2447            snapshot_edits
2448        }
2449    }
2450}