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