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