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