1use super::{
   2    fold_map,
   3    tab_map::{self, TabEdit, TabPoint, TabSnapshot},
   4    TextHighlights,
   5};
   6use crate::MultiBufferSnapshot;
   7use gpui::{
   8    fonts::FontId, text_layout::LineWrapper, Entity, ModelContext, ModelHandle, MutableAppContext,
   9    Task,
  10};
  11use language::{Chunk, Point};
  12use lazy_static::lazy_static;
  13use smol::future::yield_now;
  14use std::{cmp, collections::VecDeque, mem, ops::Range, time::Duration};
  15use sum_tree::{Bias, Cursor, SumTree};
  16use text::Patch;
  17
  18pub use super::tab_map::TextSummary;
  19pub type WrapEdit = text::Edit<u32>;
  20
  21pub struct WrapMap {
  22    snapshot: WrapSnapshot,
  23    pending_edits: VecDeque<(TabSnapshot, Vec<TabEdit>)>,
  24    interpolated_edits: Patch<u32>,
  25    edits_since_sync: Patch<u32>,
  26    wrap_width: Option<f32>,
  27    background_task: Option<Task<()>>,
  28    font: (FontId, f32),
  29}
  30
  31impl Entity for WrapMap {
  32    type Event = ();
  33}
  34
  35#[derive(Clone)]
  36pub struct WrapSnapshot {
  37    tab_snapshot: TabSnapshot,
  38    transforms: SumTree<Transform>,
  39    interpolated: bool,
  40}
  41
  42#[derive(Clone, Debug, Default, Eq, PartialEq)]
  43struct Transform {
  44    summary: TransformSummary,
  45    display_text: Option<&'static str>,
  46}
  47
  48#[derive(Clone, Debug, Default, Eq, PartialEq)]
  49struct TransformSummary {
  50    input: TextSummary,
  51    output: TextSummary,
  52}
  53
  54#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  55pub struct WrapPoint(pub Point);
  56
  57pub struct WrapChunks<'a> {
  58    input_chunks: tab_map::TabChunks<'a>,
  59    input_chunk: Chunk<'a>,
  60    output_position: WrapPoint,
  61    max_output_row: u32,
  62    transforms: Cursor<'a, Transform, (WrapPoint, TabPoint)>,
  63}
  64
  65#[derive(Clone)]
  66pub struct WrapBufferRows<'a> {
  67    input_buffer_rows: fold_map::FoldBufferRows<'a>,
  68    input_buffer_row: Option<u32>,
  69    output_row: u32,
  70    soft_wrapped: bool,
  71    max_output_row: u32,
  72    transforms: Cursor<'a, Transform, (WrapPoint, TabPoint)>,
  73}
  74
  75impl WrapMap {
  76    pub fn new(
  77        tab_snapshot: TabSnapshot,
  78        font_id: FontId,
  79        font_size: f32,
  80        wrap_width: Option<f32>,
  81        cx: &mut MutableAppContext,
  82    ) -> (ModelHandle<Self>, WrapSnapshot) {
  83        let handle = cx.add_model(|cx| {
  84            let mut this = Self {
  85                font: (font_id, font_size),
  86                wrap_width: None,
  87                pending_edits: Default::default(),
  88                interpolated_edits: Default::default(),
  89                edits_since_sync: Default::default(),
  90                snapshot: WrapSnapshot::new(tab_snapshot),
  91                background_task: None,
  92            };
  93            this.set_wrap_width(wrap_width, cx);
  94            mem::take(&mut this.edits_since_sync);
  95            this
  96        });
  97        let snapshot = handle.read(cx).snapshot.clone();
  98        (handle, snapshot)
  99    }
 100
 101    #[cfg(test)]
 102    pub fn is_rewrapping(&self) -> bool {
 103        self.background_task.is_some()
 104    }
 105
 106    pub fn sync(
 107        &mut self,
 108        tab_snapshot: TabSnapshot,
 109        edits: Vec<TabEdit>,
 110        cx: &mut ModelContext<Self>,
 111    ) -> (WrapSnapshot, Patch<u32>) {
 112        if self.wrap_width.is_some() {
 113            self.pending_edits.push_back((tab_snapshot, edits));
 114            self.flush_edits(cx);
 115        } else {
 116            self.edits_since_sync = self
 117                .edits_since_sync
 118                .compose(&self.snapshot.interpolate(tab_snapshot, &edits));
 119            self.snapshot.interpolated = false;
 120        }
 121
 122        (self.snapshot.clone(), mem::take(&mut self.edits_since_sync))
 123    }
 124
 125    pub fn set_font(
 126        &mut self,
 127        font_id: FontId,
 128        font_size: f32,
 129        cx: &mut ModelContext<Self>,
 130    ) -> bool {
 131        if (font_id, font_size) != self.font {
 132            self.font = (font_id, font_size);
 133            self.rewrap(cx);
 134            true
 135        } else {
 136            false
 137        }
 138    }
 139
 140    pub fn set_wrap_width(&mut self, wrap_width: Option<f32>, cx: &mut ModelContext<Self>) -> bool {
 141        if wrap_width == self.wrap_width {
 142            return false;
 143        }
 144
 145        self.wrap_width = wrap_width;
 146        self.rewrap(cx);
 147        true
 148    }
 149
 150    fn rewrap(&mut self, cx: &mut ModelContext<Self>) {
 151        self.background_task.take();
 152        self.interpolated_edits.clear();
 153        self.pending_edits.clear();
 154
 155        if let Some(wrap_width) = self.wrap_width {
 156            let mut new_snapshot = self.snapshot.clone();
 157            let font_cache = cx.font_cache().clone();
 158            let (font_id, font_size) = self.font;
 159            let task = cx.background().spawn(async move {
 160                let mut line_wrapper = font_cache.line_wrapper(font_id, font_size);
 161                let tab_snapshot = new_snapshot.tab_snapshot.clone();
 162                let range = TabPoint::zero()..tab_snapshot.max_point();
 163                let edits = new_snapshot
 164                    .update(
 165                        tab_snapshot,
 166                        &[TabEdit {
 167                            old: range.clone(),
 168                            new: range.clone(),
 169                        }],
 170                        wrap_width,
 171                        &mut line_wrapper,
 172                    )
 173                    .await;
 174                (new_snapshot, edits)
 175            });
 176
 177            match cx
 178                .background()
 179                .block_with_timeout(Duration::from_millis(5), task)
 180            {
 181                Ok((snapshot, edits)) => {
 182                    self.snapshot = snapshot;
 183                    self.edits_since_sync = self.edits_since_sync.compose(&edits);
 184                    cx.notify();
 185                }
 186                Err(wrap_task) => {
 187                    self.background_task = Some(cx.spawn(|this, mut cx| async move {
 188                        let (snapshot, edits) = wrap_task.await;
 189                        this.update(&mut cx, |this, cx| {
 190                            this.snapshot = snapshot;
 191                            this.edits_since_sync = this
 192                                .edits_since_sync
 193                                .compose(mem::take(&mut this.interpolated_edits).invert())
 194                                .compose(&edits);
 195                            this.background_task = None;
 196                            this.flush_edits(cx);
 197                            cx.notify();
 198                        });
 199                    }));
 200                }
 201            }
 202        } else {
 203            let old_rows = self.snapshot.transforms.summary().output.lines.row + 1;
 204            self.snapshot.transforms = SumTree::new();
 205            let summary = self.snapshot.tab_snapshot.text_summary();
 206            if !summary.lines.is_zero() {
 207                self.snapshot
 208                    .transforms
 209                    .push(Transform::isomorphic(summary), &());
 210            }
 211            let new_rows = self.snapshot.transforms.summary().output.lines.row + 1;
 212            self.snapshot.interpolated = false;
 213            self.edits_since_sync = self.edits_since_sync.compose(&Patch::new(vec![WrapEdit {
 214                old: 0..old_rows,
 215                new: 0..new_rows,
 216            }]));
 217        }
 218    }
 219
 220    fn flush_edits(&mut self, cx: &mut ModelContext<Self>) {
 221        if !self.snapshot.interpolated {
 222            let mut to_remove_len = 0;
 223            for (tab_snapshot, _) in &self.pending_edits {
 224                if tab_snapshot.version <= self.snapshot.tab_snapshot.version {
 225                    to_remove_len += 1;
 226                } else {
 227                    break;
 228                }
 229            }
 230            self.pending_edits.drain(..to_remove_len);
 231        }
 232
 233        if self.pending_edits.is_empty() {
 234            return;
 235        }
 236
 237        if let Some(wrap_width) = self.wrap_width {
 238            if self.background_task.is_none() {
 239                let pending_edits = self.pending_edits.clone();
 240                let mut snapshot = self.snapshot.clone();
 241                let font_cache = cx.font_cache().clone();
 242                let (font_id, font_size) = self.font;
 243                let update_task = cx.background().spawn(async move {
 244                    let mut line_wrapper = font_cache.line_wrapper(font_id, font_size);
 245
 246                    let mut edits = Patch::default();
 247                    for (tab_snapshot, tab_edits) in pending_edits {
 248                        let wrap_edits = snapshot
 249                            .update(tab_snapshot, &tab_edits, wrap_width, &mut line_wrapper)
 250                            .await;
 251                        edits = edits.compose(&wrap_edits);
 252                    }
 253                    (snapshot, edits)
 254                });
 255
 256                match cx
 257                    .background()
 258                    .block_with_timeout(Duration::from_millis(1), update_task)
 259                {
 260                    Ok((snapshot, output_edits)) => {
 261                        self.snapshot = snapshot;
 262                        self.edits_since_sync = self.edits_since_sync.compose(&output_edits);
 263                    }
 264                    Err(update_task) => {
 265                        self.background_task = Some(cx.spawn(|this, mut cx| async move {
 266                            let (snapshot, edits) = update_task.await;
 267                            this.update(&mut cx, |this, cx| {
 268                                this.snapshot = snapshot;
 269                                this.edits_since_sync = this
 270                                    .edits_since_sync
 271                                    .compose(mem::take(&mut this.interpolated_edits).invert())
 272                                    .compose(&edits);
 273                                this.background_task = None;
 274                                this.flush_edits(cx);
 275                                cx.notify();
 276                            });
 277                        }));
 278                    }
 279                }
 280            }
 281        }
 282
 283        let was_interpolated = self.snapshot.interpolated;
 284        let mut to_remove_len = 0;
 285        for (tab_snapshot, edits) in &self.pending_edits {
 286            if tab_snapshot.version <= self.snapshot.tab_snapshot.version {
 287                to_remove_len += 1;
 288            } else {
 289                let interpolated_edits = self.snapshot.interpolate(tab_snapshot.clone(), edits);
 290                self.edits_since_sync = self.edits_since_sync.compose(&interpolated_edits);
 291                self.interpolated_edits = self.interpolated_edits.compose(&interpolated_edits);
 292            }
 293        }
 294
 295        if !was_interpolated {
 296            self.pending_edits.drain(..to_remove_len);
 297        }
 298    }
 299}
 300
 301impl WrapSnapshot {
 302    fn new(tab_snapshot: TabSnapshot) -> Self {
 303        let mut transforms = SumTree::new();
 304        let extent = tab_snapshot.text_summary();
 305        if !extent.lines.is_zero() {
 306            transforms.push(Transform::isomorphic(extent), &());
 307        }
 308        Self {
 309            transforms,
 310            tab_snapshot,
 311            interpolated: true,
 312        }
 313    }
 314
 315    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
 316        self.tab_snapshot.buffer_snapshot()
 317    }
 318
 319    fn interpolate(&mut self, new_tab_snapshot: TabSnapshot, tab_edits: &[TabEdit]) -> Patch<u32> {
 320        let mut new_transforms;
 321        if tab_edits.is_empty() {
 322            new_transforms = self.transforms.clone();
 323        } else {
 324            let mut old_cursor = self.transforms.cursor::<TabPoint>();
 325
 326            let mut tab_edits_iter = tab_edits.iter().peekable();
 327            new_transforms =
 328                old_cursor.slice(&tab_edits_iter.peek().unwrap().old.start, Bias::Right, &());
 329
 330            while let Some(edit) = tab_edits_iter.next() {
 331                if edit.new.start > TabPoint::from(new_transforms.summary().input.lines) {
 332                    let summary = new_tab_snapshot.text_summary_for_range(
 333                        TabPoint::from(new_transforms.summary().input.lines)..edit.new.start,
 334                    );
 335                    new_transforms.push_or_extend(Transform::isomorphic(summary));
 336                }
 337
 338                if !edit.new.is_empty() {
 339                    new_transforms.push_or_extend(Transform::isomorphic(
 340                        new_tab_snapshot.text_summary_for_range(edit.new.clone()),
 341                    ));
 342                }
 343
 344                old_cursor.seek_forward(&edit.old.end, Bias::Right, &());
 345                if let Some(next_edit) = tab_edits_iter.peek() {
 346                    if next_edit.old.start > old_cursor.end(&()) {
 347                        if old_cursor.end(&()) > edit.old.end {
 348                            let summary = self
 349                                .tab_snapshot
 350                                .text_summary_for_range(edit.old.end..old_cursor.end(&()));
 351                            new_transforms.push_or_extend(Transform::isomorphic(summary));
 352                        }
 353
 354                        old_cursor.next(&());
 355                        new_transforms.push_tree(
 356                            old_cursor.slice(&next_edit.old.start, Bias::Right, &()),
 357                            &(),
 358                        );
 359                    }
 360                } else {
 361                    if old_cursor.end(&()) > edit.old.end {
 362                        let summary = self
 363                            .tab_snapshot
 364                            .text_summary_for_range(edit.old.end..old_cursor.end(&()));
 365                        new_transforms.push_or_extend(Transform::isomorphic(summary));
 366                    }
 367                    old_cursor.next(&());
 368                    new_transforms.push_tree(old_cursor.suffix(&()), &());
 369                }
 370            }
 371        }
 372
 373        let old_snapshot = mem::replace(
 374            self,
 375            WrapSnapshot {
 376                tab_snapshot: new_tab_snapshot,
 377                transforms: new_transforms,
 378                interpolated: true,
 379            },
 380        );
 381        self.check_invariants();
 382        old_snapshot.compute_edits(tab_edits, self)
 383    }
 384
 385    async fn update(
 386        &mut self,
 387        new_tab_snapshot: TabSnapshot,
 388        tab_edits: &[TabEdit],
 389        wrap_width: f32,
 390        line_wrapper: &mut LineWrapper,
 391    ) -> Patch<u32> {
 392        #[derive(Debug)]
 393        struct RowEdit {
 394            old_rows: Range<u32>,
 395            new_rows: Range<u32>,
 396        }
 397
 398        let mut tab_edits_iter = tab_edits.iter().peekable();
 399        let mut row_edits = Vec::new();
 400        while let Some(edit) = tab_edits_iter.next() {
 401            let mut row_edit = RowEdit {
 402                old_rows: edit.old.start.row()..edit.old.end.row() + 1,
 403                new_rows: edit.new.start.row()..edit.new.end.row() + 1,
 404            };
 405
 406            while let Some(next_edit) = tab_edits_iter.peek() {
 407                if next_edit.old.start.row() <= row_edit.old_rows.end {
 408                    row_edit.old_rows.end = next_edit.old.end.row() + 1;
 409                    row_edit.new_rows.end = next_edit.new.end.row() + 1;
 410                    tab_edits_iter.next();
 411                } else {
 412                    break;
 413                }
 414            }
 415
 416            row_edits.push(row_edit);
 417        }
 418
 419        let mut new_transforms;
 420        if row_edits.is_empty() {
 421            new_transforms = self.transforms.clone();
 422        } else {
 423            let mut row_edits = row_edits.into_iter().peekable();
 424            let mut old_cursor = self.transforms.cursor::<TabPoint>();
 425
 426            new_transforms = old_cursor.slice(
 427                &TabPoint::new(row_edits.peek().unwrap().old_rows.start, 0),
 428                Bias::Right,
 429                &(),
 430            );
 431
 432            while let Some(edit) = row_edits.next() {
 433                if edit.new_rows.start > new_transforms.summary().input.lines.row {
 434                    let summary = new_tab_snapshot.text_summary_for_range(
 435                        TabPoint(new_transforms.summary().input.lines)
 436                            ..TabPoint::new(edit.new_rows.start, 0),
 437                    );
 438                    new_transforms.push_or_extend(Transform::isomorphic(summary));
 439                }
 440
 441                let mut line = String::new();
 442                let mut remaining = None;
 443                let mut chunks = new_tab_snapshot.chunks(
 444                    TabPoint::new(edit.new_rows.start, 0)..new_tab_snapshot.max_point(),
 445                    false,
 446                    None,
 447                );
 448                let mut edit_transforms = Vec::<Transform>::new();
 449                for _ in edit.new_rows.start..edit.new_rows.end {
 450                    while let Some(chunk) =
 451                        remaining.take().or_else(|| chunks.next().map(|c| c.text))
 452                    {
 453                        if let Some(ix) = chunk.find('\n') {
 454                            line.push_str(&chunk[..ix + 1]);
 455                            remaining = Some(&chunk[ix + 1..]);
 456                            break;
 457                        } else {
 458                            line.push_str(chunk)
 459                        }
 460                    }
 461
 462                    if line.is_empty() {
 463                        break;
 464                    }
 465
 466                    let mut prev_boundary_ix = 0;
 467                    for boundary in line_wrapper.wrap_line(&line, wrap_width) {
 468                        let wrapped = &line[prev_boundary_ix..boundary.ix];
 469                        push_isomorphic(&mut edit_transforms, TextSummary::from(wrapped));
 470                        edit_transforms.push(Transform::wrap(boundary.next_indent));
 471                        prev_boundary_ix = boundary.ix;
 472                    }
 473
 474                    if prev_boundary_ix < line.len() {
 475                        push_isomorphic(
 476                            &mut edit_transforms,
 477                            TextSummary::from(&line[prev_boundary_ix..]),
 478                        );
 479                    }
 480
 481                    line.clear();
 482                    yield_now().await;
 483                }
 484
 485                let mut edit_transforms = edit_transforms.into_iter();
 486                if let Some(transform) = edit_transforms.next() {
 487                    new_transforms.push_or_extend(transform);
 488                }
 489                new_transforms.extend(edit_transforms, &());
 490
 491                old_cursor.seek_forward(&TabPoint::new(edit.old_rows.end, 0), Bias::Right, &());
 492                if let Some(next_edit) = row_edits.peek() {
 493                    if next_edit.old_rows.start > old_cursor.end(&()).row() {
 494                        if old_cursor.end(&()) > TabPoint::new(edit.old_rows.end, 0) {
 495                            let summary = self.tab_snapshot.text_summary_for_range(
 496                                TabPoint::new(edit.old_rows.end, 0)..old_cursor.end(&()),
 497                            );
 498                            new_transforms.push_or_extend(Transform::isomorphic(summary));
 499                        }
 500                        old_cursor.next(&());
 501                        new_transforms.push_tree(
 502                            old_cursor.slice(
 503                                &TabPoint::new(next_edit.old_rows.start, 0),
 504                                Bias::Right,
 505                                &(),
 506                            ),
 507                            &(),
 508                        );
 509                    }
 510                } else {
 511                    if old_cursor.end(&()) > TabPoint::new(edit.old_rows.end, 0) {
 512                        let summary = self.tab_snapshot.text_summary_for_range(
 513                            TabPoint::new(edit.old_rows.end, 0)..old_cursor.end(&()),
 514                        );
 515                        new_transforms.push_or_extend(Transform::isomorphic(summary));
 516                    }
 517                    old_cursor.next(&());
 518                    new_transforms.push_tree(old_cursor.suffix(&()), &());
 519                }
 520            }
 521        }
 522
 523        let old_snapshot = mem::replace(
 524            self,
 525            WrapSnapshot {
 526                tab_snapshot: new_tab_snapshot,
 527                transforms: new_transforms,
 528                interpolated: false,
 529            },
 530        );
 531        self.check_invariants();
 532        old_snapshot.compute_edits(tab_edits, self)
 533    }
 534
 535    fn compute_edits(&self, tab_edits: &[TabEdit], new_snapshot: &WrapSnapshot) -> Patch<u32> {
 536        let mut wrap_edits = Vec::new();
 537        let mut old_cursor = self.transforms.cursor::<TransformSummary>();
 538        let mut new_cursor = new_snapshot.transforms.cursor::<TransformSummary>();
 539        for mut tab_edit in tab_edits.iter().cloned() {
 540            tab_edit.old.start.0.column = 0;
 541            tab_edit.old.end.0 += Point::new(1, 0);
 542            tab_edit.new.start.0.column = 0;
 543            tab_edit.new.end.0 += Point::new(1, 0);
 544
 545            old_cursor.seek(&tab_edit.old.start, Bias::Right, &());
 546            let mut old_start = old_cursor.start().output.lines;
 547            old_start += tab_edit.old.start.0 - old_cursor.start().input.lines;
 548
 549            old_cursor.seek(&tab_edit.old.end, Bias::Right, &());
 550            let mut old_end = old_cursor.start().output.lines;
 551            old_end += tab_edit.old.end.0 - old_cursor.start().input.lines;
 552
 553            new_cursor.seek(&tab_edit.new.start, Bias::Right, &());
 554            let mut new_start = new_cursor.start().output.lines;
 555            new_start += tab_edit.new.start.0 - new_cursor.start().input.lines;
 556
 557            new_cursor.seek(&tab_edit.new.end, Bias::Right, &());
 558            let mut new_end = new_cursor.start().output.lines;
 559            new_end += tab_edit.new.end.0 - new_cursor.start().input.lines;
 560
 561            wrap_edits.push(WrapEdit {
 562                old: old_start.row..old_end.row,
 563                new: new_start.row..new_end.row,
 564            });
 565        }
 566
 567        consolidate_wrap_edits(&mut wrap_edits);
 568        Patch::new(wrap_edits)
 569    }
 570
 571    pub fn chunks<'a>(
 572        &'a self,
 573        rows: Range<u32>,
 574        language_aware: bool,
 575        text_highlights: Option<&'a TextHighlights>,
 576    ) -> WrapChunks<'a> {
 577        let output_start = WrapPoint::new(rows.start, 0);
 578        let output_end = WrapPoint::new(rows.end, 0);
 579        let mut transforms = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 580        transforms.seek(&output_start, Bias::Right, &());
 581        let mut input_start = TabPoint(transforms.start().1 .0);
 582        if transforms.item().map_or(false, |t| t.is_isomorphic()) {
 583            input_start.0 += output_start.0 - transforms.start().0 .0;
 584        }
 585        let input_end = self
 586            .to_tab_point(output_end)
 587            .min(self.tab_snapshot.max_point());
 588        WrapChunks {
 589            input_chunks: self.tab_snapshot.chunks(
 590                input_start..input_end,
 591                language_aware,
 592                text_highlights,
 593            ),
 594            input_chunk: Default::default(),
 595            output_position: output_start,
 596            max_output_row: rows.end,
 597            transforms,
 598        }
 599    }
 600
 601    pub fn max_point(&self) -> WrapPoint {
 602        WrapPoint(self.transforms.summary().output.lines)
 603    }
 604
 605    pub fn line_len(&self, row: u32) -> u32 {
 606        let mut cursor = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 607        cursor.seek(&WrapPoint::new(row + 1, 0), Bias::Left, &());
 608        if cursor
 609            .item()
 610            .map_or(false, |transform| transform.is_isomorphic())
 611        {
 612            let overshoot = row - cursor.start().0.row();
 613            let tab_row = cursor.start().1.row() + overshoot;
 614            let tab_line_len = self.tab_snapshot.line_len(tab_row);
 615            if overshoot == 0 {
 616                cursor.start().0.column() + (tab_line_len - cursor.start().1.column())
 617            } else {
 618                tab_line_len
 619            }
 620        } else {
 621            cursor.start().0.column()
 622        }
 623    }
 624
 625    pub fn soft_wrap_indent(&self, row: u32) -> Option<u32> {
 626        let mut cursor = self.transforms.cursor::<WrapPoint>();
 627        cursor.seek(&WrapPoint::new(row + 1, 0), Bias::Right, &());
 628        cursor.item().and_then(|transform| {
 629            if transform.is_isomorphic() {
 630                None
 631            } else {
 632                Some(transform.summary.output.lines.column)
 633            }
 634        })
 635    }
 636
 637    pub fn longest_row(&self) -> u32 {
 638        self.transforms.summary().output.longest_row
 639    }
 640
 641    pub fn buffer_rows(&self, start_row: u32) -> WrapBufferRows {
 642        let mut transforms = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 643        transforms.seek(&WrapPoint::new(start_row, 0), Bias::Left, &());
 644        let mut input_row = transforms.start().1.row();
 645        if transforms.item().map_or(false, |t| t.is_isomorphic()) {
 646            input_row += start_row - transforms.start().0.row();
 647        }
 648        let soft_wrapped = transforms.item().map_or(false, |t| !t.is_isomorphic());
 649        let mut input_buffer_rows = self.tab_snapshot.buffer_rows(input_row);
 650        let input_buffer_row = input_buffer_rows.next().unwrap();
 651        WrapBufferRows {
 652            transforms,
 653            input_buffer_row,
 654            input_buffer_rows,
 655            output_row: start_row,
 656            soft_wrapped,
 657            max_output_row: self.max_point().row(),
 658        }
 659    }
 660
 661    pub fn to_tab_point(&self, point: WrapPoint) -> TabPoint {
 662        let mut cursor = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 663        cursor.seek(&point, Bias::Right, &());
 664        let mut tab_point = cursor.start().1 .0;
 665        if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 666            tab_point += point.0 - cursor.start().0 .0;
 667        }
 668        TabPoint(tab_point)
 669    }
 670
 671    pub fn to_point(&self, point: WrapPoint, bias: Bias) -> Point {
 672        self.tab_snapshot.to_point(self.to_tab_point(point), bias)
 673    }
 674
 675    pub fn make_wrap_point(&self, point: Point, bias: Bias) -> WrapPoint {
 676        self.tab_point_to_wrap_point(self.tab_snapshot.make_tab_point(point, bias))
 677    }
 678
 679    pub fn tab_point_to_wrap_point(&self, point: TabPoint) -> WrapPoint {
 680        let mut cursor = self.transforms.cursor::<(TabPoint, WrapPoint)>();
 681        cursor.seek(&point, Bias::Right, &());
 682        WrapPoint(cursor.start().1 .0 + (point.0 - cursor.start().0 .0))
 683    }
 684
 685    pub fn clip_point(&self, mut point: WrapPoint, bias: Bias) -> WrapPoint {
 686        if bias == Bias::Left {
 687            let mut cursor = self.transforms.cursor::<WrapPoint>();
 688            cursor.seek(&point, Bias::Right, &());
 689            if cursor.item().map_or(false, |t| !t.is_isomorphic()) {
 690                point = *cursor.start();
 691                *point.column_mut() -= 1;
 692            }
 693        }
 694
 695        self.tab_point_to_wrap_point(self.tab_snapshot.clip_point(self.to_tab_point(point), bias))
 696    }
 697
 698    pub fn prev_row_boundary(&self, mut point: WrapPoint) -> u32 {
 699        if self.transforms.is_empty() {
 700            return 0;
 701        }
 702
 703        *point.column_mut() = 0;
 704
 705        let mut cursor = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 706        cursor.seek(&point, Bias::Right, &());
 707        if cursor.item().is_none() {
 708            cursor.prev(&());
 709        }
 710
 711        while let Some(transform) = cursor.item() {
 712            if transform.is_isomorphic() && cursor.start().1.column() == 0 {
 713                return cmp::min(cursor.end(&()).0.row(), point.row());
 714            } else {
 715                cursor.prev(&());
 716            }
 717        }
 718
 719        unreachable!()
 720    }
 721
 722    pub fn next_row_boundary(&self, mut point: WrapPoint) -> Option<u32> {
 723        point.0 += Point::new(1, 0);
 724
 725        let mut cursor = self.transforms.cursor::<(WrapPoint, TabPoint)>();
 726        cursor.seek(&point, Bias::Right, &());
 727        while let Some(transform) = cursor.item() {
 728            if transform.is_isomorphic() && cursor.start().1.column() == 0 {
 729                return Some(cmp::max(cursor.start().0.row(), point.row()));
 730            } else {
 731                cursor.next(&());
 732            }
 733        }
 734
 735        None
 736    }
 737
 738    fn check_invariants(&self) {
 739        #[cfg(test)]
 740        {
 741            assert_eq!(
 742                TabPoint::from(self.transforms.summary().input.lines),
 743                self.tab_snapshot.max_point()
 744            );
 745
 746            {
 747                let mut transforms = self.transforms.cursor::<()>().peekable();
 748                while let Some(transform) = transforms.next() {
 749                    if let Some(next_transform) = transforms.peek() {
 750                        assert!(transform.is_isomorphic() != next_transform.is_isomorphic());
 751                    }
 752                }
 753            }
 754
 755            let text = language::Rope::from(self.text().as_str());
 756            let input_buffer_rows = self.buffer_snapshot().buffer_rows(0).collect::<Vec<_>>();
 757            let mut expected_buffer_rows = Vec::new();
 758            let mut prev_tab_row = 0;
 759            for display_row in 0..=self.max_point().row() {
 760                let tab_point = self.to_tab_point(WrapPoint::new(display_row, 0));
 761                if tab_point.row() == prev_tab_row && display_row != 0 {
 762                    expected_buffer_rows.push(None);
 763                } else {
 764                    let fold_point = self.tab_snapshot.to_fold_point(tab_point, Bias::Left).0;
 765                    let buffer_point = fold_point.to_buffer_point(&self.tab_snapshot.fold_snapshot);
 766                    expected_buffer_rows.push(input_buffer_rows[buffer_point.row as usize]);
 767                    prev_tab_row = tab_point.row();
 768                }
 769
 770                assert_eq!(self.line_len(display_row), text.line_len(display_row));
 771            }
 772
 773            for start_display_row in 0..expected_buffer_rows.len() {
 774                assert_eq!(
 775                    self.buffer_rows(start_display_row as u32)
 776                        .collect::<Vec<_>>(),
 777                    &expected_buffer_rows[start_display_row..],
 778                    "invalid buffer_rows({}..)",
 779                    start_display_row
 780                );
 781            }
 782        }
 783    }
 784}
 785
 786impl<'a> Iterator for WrapChunks<'a> {
 787    type Item = Chunk<'a>;
 788
 789    fn next(&mut self) -> Option<Self::Item> {
 790        if self.output_position.row() >= self.max_output_row {
 791            return None;
 792        }
 793
 794        let transform = self.transforms.item()?;
 795        if let Some(display_text) = transform.display_text {
 796            let mut start_ix = 0;
 797            let mut end_ix = display_text.len();
 798            let mut summary = transform.summary.output.lines;
 799
 800            if self.output_position > self.transforms.start().0 {
 801                // Exclude newline starting prior to the desired row.
 802                start_ix = 1;
 803                summary.row = 0;
 804            } else if self.output_position.row() + 1 >= self.max_output_row {
 805                // Exclude soft indentation ending after the desired row.
 806                end_ix = 1;
 807                summary.column = 0;
 808            }
 809
 810            self.output_position.0 += summary;
 811            self.transforms.next(&());
 812            return Some(Chunk {
 813                text: &display_text[start_ix..end_ix],
 814                ..self.input_chunk
 815            });
 816        }
 817
 818        if self.input_chunk.text.is_empty() {
 819            self.input_chunk = self.input_chunks.next().unwrap();
 820        }
 821
 822        let mut input_len = 0;
 823        let transform_end = self.transforms.end(&()).0;
 824        for c in self.input_chunk.text.chars() {
 825            let char_len = c.len_utf8();
 826            input_len += char_len;
 827            if c == '\n' {
 828                *self.output_position.row_mut() += 1;
 829                *self.output_position.column_mut() = 0;
 830            } else {
 831                *self.output_position.column_mut() += char_len as u32;
 832            }
 833
 834            if self.output_position >= transform_end {
 835                self.transforms.next(&());
 836                break;
 837            }
 838        }
 839
 840        let (prefix, suffix) = self.input_chunk.text.split_at(input_len);
 841        self.input_chunk.text = suffix;
 842        Some(Chunk {
 843            text: prefix,
 844            ..self.input_chunk
 845        })
 846    }
 847}
 848
 849impl<'a> Iterator for WrapBufferRows<'a> {
 850    type Item = Option<u32>;
 851
 852    fn next(&mut self) -> Option<Self::Item> {
 853        if self.output_row > self.max_output_row {
 854            return None;
 855        }
 856
 857        let buffer_row = self.input_buffer_row;
 858        let soft_wrapped = self.soft_wrapped;
 859
 860        self.output_row += 1;
 861        self.transforms
 862            .seek_forward(&WrapPoint::new(self.output_row, 0), Bias::Left, &());
 863        if self.transforms.item().map_or(false, |t| t.is_isomorphic()) {
 864            self.input_buffer_row = self.input_buffer_rows.next().unwrap();
 865            self.soft_wrapped = false;
 866        } else {
 867            self.soft_wrapped = true;
 868        }
 869
 870        Some(if soft_wrapped { None } else { buffer_row })
 871    }
 872}
 873
 874impl Transform {
 875    fn isomorphic(summary: TextSummary) -> Self {
 876        #[cfg(test)]
 877        assert!(!summary.lines.is_zero());
 878
 879        Self {
 880            summary: TransformSummary {
 881                input: summary.clone(),
 882                output: summary,
 883            },
 884            display_text: None,
 885        }
 886    }
 887
 888    fn wrap(indent: u32) -> Self {
 889        lazy_static! {
 890            static ref WRAP_TEXT: String = {
 891                let mut wrap_text = String::new();
 892                wrap_text.push('\n');
 893                wrap_text.extend((0..LineWrapper::MAX_INDENT as usize).map(|_| ' '));
 894                wrap_text
 895            };
 896        }
 897
 898        Self {
 899            summary: TransformSummary {
 900                input: TextSummary::default(),
 901                output: TextSummary {
 902                    lines: Point::new(1, indent),
 903                    first_line_chars: 0,
 904                    last_line_chars: indent,
 905                    longest_row: 1,
 906                    longest_row_chars: indent,
 907                },
 908            },
 909            display_text: Some(&WRAP_TEXT[..1 + indent as usize]),
 910        }
 911    }
 912
 913    fn is_isomorphic(&self) -> bool {
 914        self.display_text.is_none()
 915    }
 916}
 917
 918impl sum_tree::Item for Transform {
 919    type Summary = TransformSummary;
 920
 921    fn summary(&self) -> Self::Summary {
 922        self.summary.clone()
 923    }
 924}
 925
 926fn push_isomorphic(transforms: &mut Vec<Transform>, summary: TextSummary) {
 927    if let Some(last_transform) = transforms.last_mut() {
 928        if last_transform.is_isomorphic() {
 929            last_transform.summary.input += &summary;
 930            last_transform.summary.output += &summary;
 931            return;
 932        }
 933    }
 934    transforms.push(Transform::isomorphic(summary));
 935}
 936
 937trait SumTreeExt {
 938    fn push_or_extend(&mut self, transform: Transform);
 939}
 940
 941impl SumTreeExt for SumTree<Transform> {
 942    fn push_or_extend(&mut self, transform: Transform) {
 943        let mut transform = Some(transform);
 944        self.update_last(
 945            |last_transform| {
 946                if last_transform.is_isomorphic() && transform.as_ref().unwrap().is_isomorphic() {
 947                    let transform = transform.take().unwrap();
 948                    last_transform.summary.input += &transform.summary.input;
 949                    last_transform.summary.output += &transform.summary.output;
 950                }
 951            },
 952            &(),
 953        );
 954
 955        if let Some(transform) = transform {
 956            self.push(transform, &());
 957        }
 958    }
 959}
 960
 961impl WrapPoint {
 962    pub fn new(row: u32, column: u32) -> Self {
 963        Self(Point::new(row, column))
 964    }
 965
 966    pub fn row(self) -> u32 {
 967        self.0.row
 968    }
 969
 970    pub fn row_mut(&mut self) -> &mut u32 {
 971        &mut self.0.row
 972    }
 973
 974    pub fn column(self) -> u32 {
 975        self.0.column
 976    }
 977
 978    pub fn column_mut(&mut self) -> &mut u32 {
 979        &mut self.0.column
 980    }
 981}
 982
 983impl sum_tree::Summary for TransformSummary {
 984    type Context = ();
 985
 986    fn add_summary(&mut self, other: &Self, _: &()) {
 987        self.input += &other.input;
 988        self.output += &other.output;
 989    }
 990}
 991
 992impl<'a> sum_tree::Dimension<'a, TransformSummary> for TabPoint {
 993    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 994        self.0 += summary.input.lines;
 995    }
 996}
 997
 998impl<'a> sum_tree::SeekTarget<'a, TransformSummary, TransformSummary> for TabPoint {
 999    fn cmp(&self, cursor_location: &TransformSummary, _: &()) -> std::cmp::Ordering {
1000        Ord::cmp(&self.0, &cursor_location.input.lines)
1001    }
1002}
1003
1004impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapPoint {
1005    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1006        self.0 += summary.output.lines;
1007    }
1008}
1009
1010fn consolidate_wrap_edits(edits: &mut Vec<WrapEdit>) {
1011    let mut i = 1;
1012    while i < edits.len() {
1013        let edit = edits[i].clone();
1014        let prev_edit = &mut edits[i - 1];
1015        if prev_edit.old.end >= edit.old.start {
1016            prev_edit.old.end = edit.old.end;
1017            prev_edit.new.end = edit.new.end;
1018            edits.remove(i);
1019            continue;
1020        }
1021        i += 1;
1022    }
1023}
1024
1025#[cfg(test)]
1026mod tests {
1027    use super::*;
1028    use crate::{
1029        display_map::{fold_map::FoldMap, tab_map::TabMap},
1030        MultiBuffer,
1031    };
1032    use gpui::test::observe;
1033    use rand::prelude::*;
1034    use settings::Settings;
1035    use smol::stream::StreamExt;
1036    use std::{cmp, env, num::NonZeroU32};
1037    use text::Rope;
1038
1039    #[gpui::test(iterations = 100)]
1040    async fn test_random_wraps(cx: &mut gpui::TestAppContext, mut rng: StdRng) {
1041        cx.update(|cx| cx.set_global(Settings::test(cx)));
1042        cx.foreground().set_block_on_ticks(0..=50);
1043        cx.foreground().forbid_parking();
1044        let operations = env::var("OPERATIONS")
1045            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1046            .unwrap_or(10);
1047
1048        let font_cache = cx.font_cache().clone();
1049        let font_system = cx.platform().fonts();
1050        let mut wrap_width = if rng.gen_bool(0.1) {
1051            None
1052        } else {
1053            Some(rng.gen_range(0.0..=1000.0))
1054        };
1055        let tab_size = NonZeroU32::new(rng.gen_range(1..=4)).unwrap();
1056        let family_id = font_cache
1057            .load_family(&["Helvetica"], &Default::default())
1058            .unwrap();
1059        let font_id = font_cache
1060            .select_font(family_id, &Default::default())
1061            .unwrap();
1062        let font_size = 14.0;
1063
1064        log::info!("Tab size: {}", tab_size);
1065        log::info!("Wrap width: {:?}", wrap_width);
1066
1067        let buffer = cx.update(|cx| {
1068            if rng.gen() {
1069                MultiBuffer::build_random(&mut rng, cx)
1070            } else {
1071                let len = rng.gen_range(0..10);
1072                let text = util::RandomCharIter::new(&mut rng)
1073                    .take(len)
1074                    .collect::<String>();
1075                MultiBuffer::build_simple(&text, cx)
1076            }
1077        });
1078        let mut buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));
1079        let (mut fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1080        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), tab_size);
1081        log::info!("Unwrapped text (no folds): {:?}", buffer_snapshot.text());
1082        log::info!(
1083            "Unwrapped text (unexpanded tabs): {:?}",
1084            folds_snapshot.text()
1085        );
1086        log::info!("Unwrapped text (expanded tabs): {:?}", tabs_snapshot.text());
1087
1088        let mut line_wrapper = LineWrapper::new(font_id, font_size, font_system);
1089        let unwrapped_text = tabs_snapshot.text();
1090        let expected_text = wrap_text(&unwrapped_text, wrap_width, &mut line_wrapper);
1091
1092        let (wrap_map, _) =
1093            cx.update(|cx| WrapMap::new(tabs_snapshot.clone(), font_id, font_size, wrap_width, cx));
1094        let mut notifications = observe(&wrap_map, cx);
1095
1096        if wrap_map.read_with(cx, |map, _| map.is_rewrapping()) {
1097            notifications.next().await.unwrap();
1098        }
1099
1100        let (initial_snapshot, _) = wrap_map.update(cx, |map, cx| {
1101            assert!(!map.is_rewrapping());
1102            map.sync(tabs_snapshot.clone(), Vec::new(), cx)
1103        });
1104
1105        let actual_text = initial_snapshot.text();
1106        assert_eq!(
1107            actual_text, expected_text,
1108            "unwrapped text is: {:?}",
1109            unwrapped_text
1110        );
1111        log::info!("Wrapped text: {:?}", actual_text);
1112
1113        let mut edits = Vec::new();
1114        for _i in 0..operations {
1115            log::info!("{} ==============================================", _i);
1116
1117            let mut buffer_edits = Vec::new();
1118            match rng.gen_range(0..=100) {
1119                0..=19 => {
1120                    wrap_width = if rng.gen_bool(0.2) {
1121                        None
1122                    } else {
1123                        Some(rng.gen_range(0.0..=1000.0))
1124                    };
1125                    log::info!("Setting wrap width to {:?}", wrap_width);
1126                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1127                }
1128                20..=39 => {
1129                    for (folds_snapshot, fold_edits) in fold_map.randomly_mutate(&mut rng) {
1130                        let (tabs_snapshot, tab_edits) =
1131                            tab_map.sync(folds_snapshot, fold_edits, tab_size);
1132                        let (mut snapshot, wrap_edits) =
1133                            wrap_map.update(cx, |map, cx| map.sync(tabs_snapshot, tab_edits, cx));
1134                        snapshot.check_invariants();
1135                        snapshot.verify_chunks(&mut rng);
1136                        edits.push((snapshot, wrap_edits));
1137                    }
1138                }
1139                _ => {
1140                    buffer.update(cx, |buffer, cx| {
1141                        let subscription = buffer.subscribe();
1142                        let edit_count = rng.gen_range(1..=5);
1143                        buffer.randomly_mutate(&mut rng, edit_count, cx);
1144                        buffer_snapshot = buffer.snapshot(cx);
1145                        buffer_edits.extend(subscription.consume());
1146                    });
1147                }
1148            }
1149
1150            log::info!("Unwrapped text (no folds): {:?}", buffer_snapshot.text());
1151            let (folds_snapshot, fold_edits) = fold_map.read(buffer_snapshot.clone(), buffer_edits);
1152            log::info!(
1153                "Unwrapped text (unexpanded tabs): {:?}",
1154                folds_snapshot.text()
1155            );
1156            let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits, tab_size);
1157            log::info!("Unwrapped text (expanded tabs): {:?}", tabs_snapshot.text());
1158
1159            let unwrapped_text = tabs_snapshot.text();
1160            let expected_text = wrap_text(&unwrapped_text, wrap_width, &mut line_wrapper);
1161            let (mut snapshot, wrap_edits) =
1162                wrap_map.update(cx, |map, cx| map.sync(tabs_snapshot.clone(), tab_edits, cx));
1163            snapshot.check_invariants();
1164            snapshot.verify_chunks(&mut rng);
1165            edits.push((snapshot, wrap_edits));
1166
1167            if wrap_map.read_with(cx, |map, _| map.is_rewrapping()) && rng.gen_bool(0.4) {
1168                log::info!("Waiting for wrapping to finish");
1169                while wrap_map.read_with(cx, |map, _| map.is_rewrapping()) {
1170                    notifications.next().await.unwrap();
1171                }
1172                wrap_map.read_with(cx, |map, _| assert!(map.pending_edits.is_empty()));
1173            }
1174
1175            if !wrap_map.read_with(cx, |map, _| map.is_rewrapping()) {
1176                let (mut wrapped_snapshot, wrap_edits) =
1177                    wrap_map.update(cx, |map, cx| map.sync(tabs_snapshot, Vec::new(), cx));
1178                let actual_text = wrapped_snapshot.text();
1179                let actual_longest_row = wrapped_snapshot.longest_row();
1180                log::info!("Wrapping finished: {:?}", actual_text);
1181                wrapped_snapshot.check_invariants();
1182                wrapped_snapshot.verify_chunks(&mut rng);
1183                edits.push((wrapped_snapshot.clone(), wrap_edits));
1184                assert_eq!(
1185                    actual_text, expected_text,
1186                    "unwrapped text is: {:?}",
1187                    unwrapped_text
1188                );
1189
1190                let mut summary = TextSummary::default();
1191                for (ix, item) in wrapped_snapshot
1192                    .transforms
1193                    .items(&())
1194                    .into_iter()
1195                    .enumerate()
1196                {
1197                    summary += &item.summary.output;
1198                    log::info!("{} summary: {:?}", ix, item.summary.output,);
1199                }
1200
1201                if tab_size.get() == 1
1202                    || !wrapped_snapshot
1203                        .tab_snapshot
1204                        .fold_snapshot
1205                        .text()
1206                        .contains('\t')
1207                {
1208                    let mut expected_longest_rows = Vec::new();
1209                    let mut longest_line_len = -1;
1210                    for (row, line) in expected_text.split('\n').enumerate() {
1211                        let line_char_count = line.chars().count() as isize;
1212                        if line_char_count > longest_line_len {
1213                            expected_longest_rows.clear();
1214                            longest_line_len = line_char_count;
1215                        }
1216                        if line_char_count >= longest_line_len {
1217                            expected_longest_rows.push(row as u32);
1218                        }
1219                    }
1220
1221                    assert!(
1222                        expected_longest_rows.contains(&actual_longest_row),
1223                        "incorrect longest row {}. expected {:?} with length {}",
1224                        actual_longest_row,
1225                        expected_longest_rows,
1226                        longest_line_len,
1227                    )
1228                }
1229            }
1230        }
1231
1232        let mut initial_text = Rope::from(initial_snapshot.text().as_str());
1233        for (snapshot, patch) in edits {
1234            let snapshot_text = Rope::from(snapshot.text().as_str());
1235            for edit in &patch {
1236                let old_start = initial_text.point_to_offset(Point::new(edit.new.start, 0));
1237                let old_end = initial_text.point_to_offset(cmp::min(
1238                    Point::new(edit.new.start + edit.old.len() as u32, 0),
1239                    initial_text.max_point(),
1240                ));
1241                let new_start = snapshot_text.point_to_offset(Point::new(edit.new.start, 0));
1242                let new_end = snapshot_text.point_to_offset(cmp::min(
1243                    Point::new(edit.new.end, 0),
1244                    snapshot_text.max_point(),
1245                ));
1246                let new_text = snapshot_text
1247                    .chunks_in_range(new_start..new_end)
1248                    .collect::<String>();
1249
1250                initial_text.replace(old_start..old_end, &new_text);
1251            }
1252            assert_eq!(initial_text.to_string(), snapshot_text.to_string());
1253        }
1254
1255        if wrap_map.read_with(cx, |map, _| map.is_rewrapping()) {
1256            log::info!("Waiting for wrapping to finish");
1257            while wrap_map.read_with(cx, |map, _| map.is_rewrapping()) {
1258                notifications.next().await.unwrap();
1259            }
1260        }
1261        wrap_map.read_with(cx, |map, _| assert!(map.pending_edits.is_empty()));
1262    }
1263
1264    fn wrap_text(
1265        unwrapped_text: &str,
1266        wrap_width: Option<f32>,
1267        line_wrapper: &mut LineWrapper,
1268    ) -> String {
1269        if let Some(wrap_width) = wrap_width {
1270            let mut wrapped_text = String::new();
1271            for (row, line) in unwrapped_text.split('\n').enumerate() {
1272                if row > 0 {
1273                    wrapped_text.push('\n')
1274                }
1275
1276                let mut prev_ix = 0;
1277                for boundary in line_wrapper.wrap_line(line, wrap_width) {
1278                    wrapped_text.push_str(&line[prev_ix..boundary.ix]);
1279                    wrapped_text.push('\n');
1280                    wrapped_text.push_str(&" ".repeat(boundary.next_indent as usize));
1281                    prev_ix = boundary.ix;
1282                }
1283                wrapped_text.push_str(&line[prev_ix..]);
1284            }
1285            wrapped_text
1286        } else {
1287            unwrapped_text.to_string()
1288        }
1289    }
1290
1291    impl WrapSnapshot {
1292        pub fn text(&self) -> String {
1293            self.text_chunks(0).collect()
1294        }
1295
1296        pub fn text_chunks(&self, wrap_row: u32) -> impl Iterator<Item = &str> {
1297            self.chunks(wrap_row..self.max_point().row() + 1, false, None)
1298                .map(|h| h.text)
1299        }
1300
1301        fn verify_chunks(&mut self, rng: &mut impl Rng) {
1302            for _ in 0..5 {
1303                let mut end_row = rng.gen_range(0..=self.max_point().row());
1304                let start_row = rng.gen_range(0..=end_row);
1305                end_row += 1;
1306
1307                let mut expected_text = self.text_chunks(start_row).collect::<String>();
1308                if expected_text.ends_with('\n') {
1309                    expected_text.push('\n');
1310                }
1311                let mut expected_text = expected_text
1312                    .lines()
1313                    .take((end_row - start_row) as usize)
1314                    .collect::<Vec<_>>()
1315                    .join("\n");
1316                if end_row <= self.max_point().row() {
1317                    expected_text.push('\n');
1318                }
1319
1320                let actual_text = self
1321                    .chunks(start_row..end_row, true, None)
1322                    .map(|c| c.text)
1323                    .collect::<String>();
1324                assert_eq!(
1325                    expected_text,
1326                    actual_text,
1327                    "chunks != highlighted_chunks for rows {:?}",
1328                    start_row..end_row
1329                );
1330            }
1331        }
1332    }
1333}