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