wrap_map.rs

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