block_map.rs

   1use super::wrap_map::{self, Edit as WrapEdit, Snapshot as WrapSnapshot, WrapPoint};
   2use buffer::{rope, Anchor, Bias, Edit, Point, Rope, ToOffset, ToPoint as _};
   3use gpui::{fonts::HighlightStyle, AppContext, ModelHandle};
   4use language::{Buffer, Chunk};
   5use parking_lot::Mutex;
   6use std::{
   7    cmp::{self, Ordering},
   8    collections::HashSet,
   9    iter,
  10    ops::Range,
  11    slice,
  12    sync::{
  13        atomic::{AtomicUsize, Ordering::SeqCst},
  14        Arc,
  15    },
  16};
  17use sum_tree::SumTree;
  18
  19pub struct BlockMap {
  20    buffer: ModelHandle<Buffer>,
  21    next_block_id: AtomicUsize,
  22    wrap_snapshot: Mutex<WrapSnapshot>,
  23    blocks: Vec<Arc<Block>>,
  24    transforms: Mutex<SumTree<Transform>>,
  25}
  26
  27pub struct BlockMapWriter<'a>(&'a mut BlockMap);
  28
  29pub struct BlockSnapshot {
  30    wrap_snapshot: WrapSnapshot,
  31    transforms: SumTree<Transform>,
  32}
  33
  34#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
  35pub struct BlockId(usize);
  36
  37#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  38pub struct BlockPoint(pub super::Point);
  39
  40#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  41struct BlockRow(u32);
  42
  43#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  44struct WrapRow(u32);
  45
  46#[derive(Debug)]
  47struct Block {
  48    id: BlockId,
  49    position: Anchor,
  50    text: Rope,
  51    runs: Vec<(usize, HighlightStyle)>,
  52    disposition: BlockDisposition,
  53}
  54
  55#[derive(Clone)]
  56pub struct BlockProperties<P, T>
  57where
  58    P: Clone,
  59    T: Clone,
  60{
  61    pub position: P,
  62    pub text: T,
  63    pub runs: Vec<(usize, HighlightStyle)>,
  64    pub disposition: BlockDisposition,
  65}
  66
  67#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
  68pub enum BlockDisposition {
  69    Above,
  70    Below,
  71}
  72
  73#[derive(Clone, Debug)]
  74struct Transform {
  75    summary: TransformSummary,
  76    block: Option<Arc<Block>>,
  77}
  78
  79#[derive(Clone, Debug, Default)]
  80struct TransformSummary {
  81    input_rows: u32,
  82    output_rows: u32,
  83    longest_row_in_block: u32,
  84    longest_row_in_block_chars: u32,
  85}
  86
  87pub struct Chunks<'a> {
  88    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
  89    input_chunks: wrap_map::Chunks<'a>,
  90    input_chunk: Chunk<'a>,
  91    block_chunks: Option<BlockChunks<'a>>,
  92    output_row: u32,
  93    max_output_row: u32,
  94}
  95
  96struct BlockChunks<'a> {
  97    chunks: rope::Chunks<'a>,
  98    runs: iter::Peekable<slice::Iter<'a, (usize, HighlightStyle)>>,
  99    chunk: Option<&'a str>,
 100    run_start: usize,
 101    offset: usize,
 102}
 103
 104pub struct BufferRows<'a> {
 105    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 106    input_buffer_rows: wrap_map::BufferRows<'a>,
 107    output_row: u32,
 108    started: bool,
 109}
 110
 111impl BlockMap {
 112    pub fn new(buffer: ModelHandle<Buffer>, wrap_snapshot: WrapSnapshot) -> Self {
 113        Self {
 114            buffer,
 115            next_block_id: AtomicUsize::new(0),
 116            blocks: Vec::new(),
 117            transforms: Mutex::new(SumTree::from_item(
 118                Transform::isomorphic(wrap_snapshot.text_summary().lines.row + 1),
 119                &(),
 120            )),
 121            wrap_snapshot: Mutex::new(wrap_snapshot),
 122        }
 123    }
 124
 125    pub fn read(
 126        &self,
 127        wrap_snapshot: WrapSnapshot,
 128        edits: Vec<WrapEdit>,
 129        cx: &AppContext,
 130    ) -> BlockSnapshot {
 131        self.sync(&wrap_snapshot, edits, cx);
 132        *self.wrap_snapshot.lock() = wrap_snapshot.clone();
 133        BlockSnapshot {
 134            wrap_snapshot,
 135            transforms: self.transforms.lock().clone(),
 136        }
 137    }
 138
 139    pub fn write(
 140        &mut self,
 141        wrap_snapshot: WrapSnapshot,
 142        edits: Vec<WrapEdit>,
 143        cx: &AppContext,
 144    ) -> BlockMapWriter {
 145        self.sync(&wrap_snapshot, edits, cx);
 146        *self.wrap_snapshot.lock() = wrap_snapshot;
 147        BlockMapWriter(self)
 148    }
 149
 150    pub fn sync(&self, wrap_snapshot: &WrapSnapshot, edits: Vec<WrapEdit>, cx: &AppContext) {
 151        if edits.is_empty() {
 152            return;
 153        }
 154
 155        let buffer = self.buffer.read(cx);
 156        let mut transforms = self.transforms.lock();
 157        let mut new_transforms = SumTree::new();
 158        let old_row_count = transforms.summary().input_rows;
 159        let new_row_count = wrap_snapshot.max_point().row() + 1;
 160        let mut cursor = transforms.cursor::<WrapRow>();
 161        let mut last_block_ix = 0;
 162        let mut blocks_in_edit = Vec::new();
 163        let mut edits = edits.into_iter().peekable();
 164
 165        while let Some(edit) = edits.next() {
 166            // Preserve any old transforms that precede this edit.
 167            let old_start = WrapRow(edit.old.start);
 168            let new_start = WrapRow(edit.new.start);
 169            new_transforms.push_tree(cursor.slice(&old_start, Bias::Left, &()), &());
 170            if let Some(transform) = cursor.item() {
 171                if transform.is_isomorphic() && old_start == cursor.end(&()) {
 172                    new_transforms.push(transform.clone(), &());
 173                    cursor.next(&());
 174                    while let Some(transform) = cursor.item() {
 175                        if transform
 176                            .block
 177                            .as_ref()
 178                            .map_or(false, |b| b.disposition.is_below())
 179                        {
 180                            new_transforms.push(transform.clone(), &());
 181                            cursor.next(&());
 182                        } else {
 183                            break;
 184                        }
 185                    }
 186                }
 187            }
 188
 189            // Preserve any portion of an old transform that precedes this edit.
 190            let extent_before_edit = old_start.0 - cursor.start().0;
 191            push_isomorphic(&mut new_transforms, extent_before_edit);
 192
 193            // Skip over any old transforms that intersect this edit.
 194            let mut old_end = WrapRow(edit.old.end);
 195            let mut new_end = WrapRow(edit.new.end);
 196            cursor.seek(&old_end, Bias::Left, &());
 197            cursor.next(&());
 198            if old_end == *cursor.start() {
 199                while let Some(transform) = cursor.item() {
 200                    if transform
 201                        .block
 202                        .as_ref()
 203                        .map_or(false, |b| b.disposition.is_below())
 204                    {
 205                        cursor.next(&());
 206                    } else {
 207                        break;
 208                    }
 209                }
 210            }
 211
 212            // Combine this edit with any subsequent edits that intersect the same transform.
 213            while let Some(next_edit) = edits.peek() {
 214                if next_edit.old.start <= cursor.start().0 {
 215                    old_end = WrapRow(next_edit.old.end);
 216                    new_end = WrapRow(next_edit.new.end);
 217                    cursor.seek(&old_end, Bias::Left, &());
 218                    cursor.next(&());
 219                    if old_end == *cursor.start() {
 220                        while let Some(transform) = cursor.item() {
 221                            if transform
 222                                .block
 223                                .as_ref()
 224                                .map_or(false, |b| b.disposition.is_below())
 225                            {
 226                                cursor.next(&());
 227                            } else {
 228                                break;
 229                            }
 230                        }
 231                    }
 232                    edits.next();
 233                } else {
 234                    break;
 235                }
 236            }
 237
 238            // Find the blocks within this edited region.
 239            let new_start = wrap_snapshot.to_point(WrapPoint::new(new_start.0, 0), Bias::Left);
 240            let start_anchor = buffer.anchor_before(new_start);
 241            let start_block_ix = match self.blocks[last_block_ix..].binary_search_by(|probe| {
 242                probe
 243                    .position
 244                    .cmp(&start_anchor, buffer)
 245                    .unwrap()
 246                    .then(Ordering::Greater)
 247            }) {
 248                Ok(ix) | Err(ix) => last_block_ix + ix,
 249            };
 250            let end_block_ix = if new_end.0 > wrap_snapshot.max_point().row() {
 251                self.blocks.len()
 252            } else {
 253                let new_end = wrap_snapshot.to_point(WrapPoint::new(new_end.0, 0), Bias::Left);
 254                let end_anchor = buffer.anchor_before(new_end);
 255                match self.blocks[start_block_ix..].binary_search_by(|probe| {
 256                    probe
 257                        .position
 258                        .cmp(&end_anchor, buffer)
 259                        .unwrap()
 260                        .then(Ordering::Greater)
 261                }) {
 262                    Ok(ix) | Err(ix) => start_block_ix + ix,
 263                }
 264            };
 265            last_block_ix = end_block_ix;
 266            blocks_in_edit.clear();
 267            blocks_in_edit.extend(
 268                self.blocks[start_block_ix..end_block_ix]
 269                    .iter()
 270                    .map(|block| {
 271                        let mut position = block.position.to_point(buffer);
 272                        match block.disposition {
 273                            BlockDisposition::Above => position.column = 0,
 274                            BlockDisposition::Below => {
 275                                position.column = buffer.line_len(position.row)
 276                            }
 277                        }
 278                        let position = wrap_snapshot.from_point(position, Bias::Left);
 279                        (position.row(), block)
 280                    }),
 281            );
 282            blocks_in_edit.sort_unstable_by_key(|(row, block)| (*row, block.disposition, block.id));
 283
 284            // For each of these blocks, insert a new isomorphic transform preceding the block,
 285            // and then insert the block itself.
 286            for (block_row, block) in blocks_in_edit.iter().copied() {
 287                let insertion_row = match block.disposition {
 288                    BlockDisposition::Above => block_row,
 289                    BlockDisposition::Below => block_row + 1,
 290                };
 291                let extent_before_block = insertion_row - new_transforms.summary().input_rows;
 292                push_isomorphic(&mut new_transforms, extent_before_block);
 293                new_transforms.push(Transform::block(block.clone()), &());
 294            }
 295
 296            old_end = WrapRow(old_end.0.min(old_row_count));
 297            new_end = WrapRow(new_end.0.min(new_row_count));
 298
 299            // Insert an isomorphic transform after the final block.
 300            let extent_after_last_block = new_end.0 - new_transforms.summary().input_rows;
 301            push_isomorphic(&mut new_transforms, extent_after_last_block);
 302
 303            // Preserve any portion of the old transform after this edit.
 304            let extent_after_edit = cursor.start().0 - old_end.0;
 305            push_isomorphic(&mut new_transforms, extent_after_edit);
 306        }
 307
 308        new_transforms.push_tree(cursor.suffix(&()), &());
 309        debug_assert_eq!(
 310            new_transforms.summary().input_rows,
 311            wrap_snapshot.max_point().row() + 1
 312        );
 313
 314        drop(cursor);
 315        *transforms = new_transforms;
 316    }
 317}
 318
 319fn push_isomorphic(tree: &mut SumTree<Transform>, rows: u32) {
 320    if rows == 0 {
 321        return;
 322    }
 323
 324    let mut extent = Some(rows);
 325    tree.update_last(
 326        |last_transform| {
 327            if last_transform.is_isomorphic() {
 328                let extent = extent.take().unwrap();
 329                last_transform.summary.input_rows += extent;
 330                last_transform.summary.output_rows += extent;
 331            }
 332        },
 333        &(),
 334    );
 335    if let Some(extent) = extent {
 336        tree.push(Transform::isomorphic(extent), &());
 337    }
 338}
 339
 340impl BlockPoint {
 341    pub fn new(row: u32, column: u32) -> Self {
 342        Self(Point::new(row, column))
 343    }
 344}
 345
 346impl std::ops::Deref for BlockPoint {
 347    type Target = Point;
 348
 349    fn deref(&self) -> &Self::Target {
 350        &self.0
 351    }
 352}
 353
 354impl std::ops::DerefMut for BlockPoint {
 355    fn deref_mut(&mut self) -> &mut Self::Target {
 356        &mut self.0
 357    }
 358}
 359
 360impl<'a> BlockMapWriter<'a> {
 361    pub fn insert<P, T>(
 362        &mut self,
 363        blocks: impl IntoIterator<Item = BlockProperties<P, T>>,
 364        cx: &AppContext,
 365    ) -> Vec<BlockId>
 366    where
 367        P: ToOffset + Clone,
 368        T: Into<Rope> + Clone,
 369    {
 370        let buffer = self.0.buffer.read(cx);
 371        let mut ids = Vec::new();
 372        let mut edits = Vec::<Edit<u32>>::new();
 373        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 374
 375        for block in blocks {
 376            let id = BlockId(self.0.next_block_id.fetch_add(1, SeqCst));
 377            ids.push(id);
 378
 379            let position = buffer.anchor_before(block.position);
 380            let point = position.to_point(buffer);
 381            let start_row = wrap_snapshot
 382                .from_point(Point::new(point.row, 0), Bias::Left)
 383                .row();
 384            let end_row = if point.row == buffer.max_point().row {
 385                wrap_snapshot.max_point().row() + 1
 386            } else {
 387                wrap_snapshot
 388                    .from_point(Point::new(point.row + 1, 0), Bias::Left)
 389                    .row()
 390            };
 391
 392            let block_ix = match self
 393                .0
 394                .blocks
 395                .binary_search_by(|probe| probe.position.cmp(&position, buffer).unwrap())
 396            {
 397                Ok(ix) | Err(ix) => ix,
 398            };
 399            self.0.blocks.insert(
 400                block_ix,
 401                Arc::new(Block {
 402                    id,
 403                    position,
 404                    text: block.text.into(),
 405                    runs: block.runs,
 406                    disposition: block.disposition,
 407                }),
 408            );
 409
 410            if let Err(edit_ix) = edits.binary_search_by_key(&start_row, |edit| edit.old.start) {
 411                edits.insert(
 412                    edit_ix,
 413                    Edit {
 414                        old: start_row..end_row,
 415                        new: start_row..end_row,
 416                    },
 417                );
 418            }
 419        }
 420
 421        self.0.sync(wrap_snapshot, edits, cx);
 422        ids
 423    }
 424
 425    pub fn remove(&mut self, block_ids: HashSet<BlockId>, cx: &AppContext) {
 426        let buffer = self.0.buffer.read(cx);
 427        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 428        let mut edits = Vec::new();
 429        let mut last_block_buffer_row = None;
 430        self.0.blocks.retain(|block| {
 431            if block_ids.contains(&block.id) {
 432                let buffer_row = block.position.to_point(buffer).row;
 433                if last_block_buffer_row != Some(buffer_row) {
 434                    last_block_buffer_row = Some(buffer_row);
 435                    let start_row = wrap_snapshot
 436                        .from_point(Point::new(buffer_row, 0), Bias::Left)
 437                        .row();
 438                    let end_row = wrap_snapshot
 439                        .from_point(
 440                            Point::new(buffer_row, buffer.line_len(buffer_row)),
 441                            Bias::Left,
 442                        )
 443                        .row()
 444                        + 1;
 445                    edits.push(Edit {
 446                        old: start_row..end_row,
 447                        new: start_row..end_row,
 448                    })
 449                }
 450                false
 451            } else {
 452                true
 453            }
 454        });
 455        self.0.sync(wrap_snapshot, edits, cx);
 456    }
 457}
 458
 459impl BlockSnapshot {
 460    #[cfg(test)]
 461    fn text(&mut self) -> String {
 462        self.chunks(0..self.transforms.summary().output_rows, false)
 463            .map(|chunk| chunk.text)
 464            .collect()
 465    }
 466
 467    pub fn chunks(&self, rows: Range<u32>, highlights: bool) -> Chunks {
 468        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 469        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 470        let input_end = {
 471            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 472            let overshoot = if cursor
 473                .item()
 474                .map_or(false, |transform| transform.is_isomorphic())
 475            {
 476                rows.end - cursor.start().0 .0
 477            } else {
 478                0
 479            };
 480            cursor.start().1 .0 + overshoot
 481        };
 482        let input_start = {
 483            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 484            let overshoot = if cursor
 485                .item()
 486                .map_or(false, |transform| transform.is_isomorphic())
 487            {
 488                rows.start - cursor.start().0 .0
 489            } else {
 490                0
 491            };
 492            cursor.start().1 .0 + overshoot
 493        };
 494        Chunks {
 495            input_chunks: self
 496                .wrap_snapshot
 497                .chunks(input_start..input_end, highlights),
 498            input_chunk: Default::default(),
 499            block_chunks: None,
 500            transforms: cursor,
 501            output_row: rows.start,
 502            max_output_row,
 503        }
 504    }
 505
 506    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 507        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 508        cursor.seek(&BlockRow(start_row), Bias::Right, &());
 509        let (input_start, output_start) = cursor.start();
 510        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 511            start_row - output_start.0
 512        } else {
 513            0
 514        };
 515        let input_start_row = input_start.0 + overshoot;
 516        BufferRows {
 517            transforms: cursor,
 518            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 519            output_row: start_row,
 520            started: false,
 521        }
 522    }
 523
 524    pub fn max_point(&self) -> BlockPoint {
 525        let row = self.transforms.summary().output_rows - 1;
 526        BlockPoint::new(row, self.line_len(row))
 527    }
 528
 529    pub fn longest_row(&self) -> u32 {
 530        let input_row = self.wrap_snapshot.longest_row();
 531        let input_row_len = self.wrap_snapshot.line_len(input_row);
 532        let TransformSummary {
 533            longest_row_in_block: block_row,
 534            longest_row_in_block_chars: block_row_len,
 535            ..
 536        } = &self.transforms.summary();
 537
 538        dbg!(block_row, block_row_len, input_row, input_row_len);
 539
 540        if *block_row_len > input_row_len {
 541            *block_row
 542        } else {
 543            self.to_block_point(WrapPoint::new(input_row, 0)).row
 544        }
 545    }
 546
 547    pub fn line_len(&self, row: u32) -> u32 {
 548        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 549        cursor.seek(&BlockRow(row), Bias::Right, &());
 550        if let Some(transform) = cursor.item() {
 551            let (output_start, input_start) = cursor.start();
 552            let overshoot = row - output_start.0;
 553            if let Some(block) = &transform.block {
 554                block.text.line_len(overshoot)
 555            } else {
 556                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 557            }
 558        } else {
 559            panic!("row out of range");
 560        }
 561    }
 562
 563    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 564        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 565        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 566
 567        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 568        let search_left =
 569            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 570
 571        loop {
 572            if let Some(transform) = cursor.item() {
 573                if transform.is_isomorphic() {
 574                    let (output_start_row, input_start_row) = cursor.start();
 575                    let (output_end_row, input_end_row) = cursor.end(&());
 576
 577                    if point.row >= output_end_row.0 {
 578                        return BlockPoint::new(
 579                            output_end_row.0 - 1,
 580                            self.wrap_snapshot.line_len(input_end_row.0 - 1),
 581                        );
 582                    }
 583
 584                    let output_start = Point::new(output_start_row.0, 0);
 585                    if point.0 > output_start {
 586                        let output_overshoot = point.0 - output_start;
 587                        let input_start = Point::new(input_start_row.0, 0);
 588                        let input_point = self
 589                            .wrap_snapshot
 590                            .clip_point(WrapPoint(input_start + output_overshoot), bias);
 591                        let input_overshoot = input_point.0 - input_start;
 592                        return BlockPoint(output_start + input_overshoot);
 593                    } else {
 594                        return BlockPoint(output_start);
 595                    }
 596                } else if search_left {
 597                    cursor.prev(&());
 598                } else {
 599                    cursor.next(&());
 600                }
 601            } else {
 602                return self.max_point();
 603            }
 604        }
 605    }
 606
 607    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 608        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 609        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 610        if let Some(transform) = cursor.item() {
 611            debug_assert!(transform.is_isomorphic());
 612        } else {
 613            return self.max_point();
 614        }
 615
 616        let (input_start_row, output_start_row) = cursor.start();
 617        let input_start = Point::new(input_start_row.0, 0);
 618        let output_start = Point::new(output_start_row.0, 0);
 619        let input_overshoot = wrap_point.0 - input_start;
 620        BlockPoint(output_start + input_overshoot)
 621    }
 622
 623    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 624        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 625        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 626        if let Some(transform) = cursor.item() {
 627            match transform.block.as_ref().map(|b| b.disposition) {
 628                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 629                Some(BlockDisposition::Below) => {
 630                    let wrap_row = cursor.start().1 .0 - 1;
 631                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
 632                }
 633                None => {
 634                    let overshoot = block_point.row - cursor.start().0 .0;
 635                    let wrap_row = cursor.start().1 .0 + overshoot;
 636                    WrapPoint::new(wrap_row, block_point.column)
 637                }
 638            }
 639        } else {
 640            self.wrap_snapshot.max_point()
 641        }
 642    }
 643}
 644
 645impl Transform {
 646    fn isomorphic(rows: u32) -> Self {
 647        Self {
 648            summary: TransformSummary {
 649                input_rows: rows,
 650                output_rows: rows,
 651                longest_row_in_block: 0,
 652                longest_row_in_block_chars: 0,
 653            },
 654            block: None,
 655        }
 656    }
 657
 658    fn block(block: Arc<Block>) -> Self {
 659        let text_summary = block.text.summary();
 660        Self {
 661            summary: TransformSummary {
 662                input_rows: 0,
 663                output_rows: text_summary.lines.row + 1,
 664                longest_row_in_block: text_summary.longest_row,
 665                longest_row_in_block_chars: text_summary.longest_row_chars,
 666            },
 667            block: Some(block),
 668        }
 669    }
 670
 671    fn is_isomorphic(&self) -> bool {
 672        self.block.is_none()
 673    }
 674}
 675
 676impl<'a> Iterator for Chunks<'a> {
 677    type Item = Chunk<'a>;
 678
 679    fn next(&mut self) -> Option<Self::Item> {
 680        if self.output_row >= self.max_output_row {
 681            return None;
 682        }
 683
 684        if let Some(block_chunks) = self.block_chunks.as_mut() {
 685            if let Some(block_chunk) = block_chunks.next() {
 686                self.output_row += block_chunk.text.matches('\n').count() as u32;
 687                return Some(block_chunk);
 688            } else {
 689                self.block_chunks.take();
 690                self.output_row += 1;
 691                if self.output_row < self.max_output_row {
 692                    return Some(Chunk {
 693                        text: "\n",
 694                        ..Default::default()
 695                    });
 696                } else {
 697                    return None;
 698                }
 699            }
 700        }
 701
 702        let transform = self.transforms.item()?;
 703        if let Some(block) = transform.block.as_ref() {
 704            let block_start = self.transforms.start().0 .0;
 705            let block_end = self.transforms.end(&()).0 .0;
 706            let start_in_block = self.output_row - block_start;
 707            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
 708            self.transforms.next(&());
 709            self.block_chunks = Some(BlockChunks::new(block, start_in_block..end_in_block));
 710            return self.next();
 711        }
 712
 713        if self.input_chunk.text.is_empty() {
 714            if let Some(input_chunk) = self.input_chunks.next() {
 715                self.input_chunk = input_chunk;
 716            } else {
 717                self.output_row += 1;
 718                if self.output_row < self.max_output_row {
 719                    self.transforms.next(&());
 720                    return Some(Chunk {
 721                        text: "\n",
 722                        ..Default::default()
 723                    });
 724                } else {
 725                    return None;
 726                }
 727            }
 728        }
 729
 730        let transform_end = self.transforms.end(&()).0 .0;
 731        let (prefix_rows, prefix_bytes) =
 732            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
 733        self.output_row += prefix_rows;
 734        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
 735        self.input_chunk.text = suffix;
 736        if self.output_row == transform_end {
 737            self.transforms.next(&());
 738        }
 739
 740        Some(Chunk {
 741            text: prefix,
 742            ..self.input_chunk
 743        })
 744    }
 745}
 746
 747impl<'a> BlockChunks<'a> {
 748    fn new(block: &'a Block, rows: Range<u32>) -> Self {
 749        let offset_range = block.text.point_to_offset(Point::new(rows.start, 0))
 750            ..block.text.point_to_offset(Point::new(rows.end, 0));
 751
 752        let mut runs = block.runs.iter().peekable();
 753        let mut run_start = 0;
 754        while let Some((run_len, _)) = runs.peek() {
 755            let run_end = run_start + run_len;
 756            if run_end <= offset_range.start {
 757                run_start = run_end;
 758                runs.next();
 759            } else {
 760                break;
 761            }
 762        }
 763
 764        Self {
 765            chunk: None,
 766            run_start,
 767            chunks: block.text.chunks_in_range(offset_range.clone()),
 768            runs,
 769            offset: offset_range.start,
 770        }
 771    }
 772}
 773
 774impl<'a> Iterator for BlockChunks<'a> {
 775    type Item = Chunk<'a>;
 776
 777    fn next(&mut self) -> Option<Self::Item> {
 778        if self.chunk.is_none() {
 779            self.chunk = self.chunks.next();
 780        }
 781
 782        let chunk = self.chunk?;
 783        let mut chunk_len = chunk.len();
 784        // let mut highlight_style = None;
 785        if let Some((run_len, _)) = self.runs.peek() {
 786            // highlight_style = Some(style.clone());
 787            let run_end_in_chunk = self.run_start + run_len - self.offset;
 788            if run_end_in_chunk <= chunk_len {
 789                chunk_len = run_end_in_chunk;
 790                self.run_start += run_len;
 791                self.runs.next();
 792            }
 793        }
 794
 795        self.offset += chunk_len;
 796        let (chunk, suffix) = chunk.split_at(chunk_len);
 797        self.chunk = if suffix.is_empty() {
 798            None
 799        } else {
 800            Some(suffix)
 801        };
 802
 803        Some(Chunk {
 804            text: chunk,
 805            highlight_id: Default::default(),
 806            diagnostic: None,
 807        })
 808    }
 809}
 810
 811impl<'a> Iterator for BufferRows<'a> {
 812    type Item = Option<u32>;
 813
 814    fn next(&mut self) -> Option<Self::Item> {
 815        if self.started {
 816            self.output_row += 1;
 817        } else {
 818            self.started = true;
 819        }
 820
 821        if self.output_row >= self.transforms.end(&()).0 .0 {
 822            self.transforms.next(&());
 823        }
 824
 825        let transform = self.transforms.item()?;
 826        if transform.is_isomorphic() {
 827            Some(self.input_buffer_rows.next().unwrap())
 828        } else {
 829            Some(None)
 830        }
 831    }
 832}
 833
 834impl sum_tree::Item for Transform {
 835    type Summary = TransformSummary;
 836
 837    fn summary(&self) -> Self::Summary {
 838        self.summary.clone()
 839    }
 840}
 841
 842impl sum_tree::Summary for TransformSummary {
 843    type Context = ();
 844
 845    fn add_summary(&mut self, summary: &Self, _: &()) {
 846        if summary.longest_row_in_block_chars > self.longest_row_in_block_chars {
 847            self.longest_row_in_block_chars = summary.longest_row_in_block_chars;
 848            self.longest_row_in_block = self.output_rows + summary.longest_row_in_block;
 849        }
 850
 851        self.input_rows += summary.input_rows;
 852        self.output_rows += summary.output_rows;
 853    }
 854}
 855
 856impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
 857    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 858        self.0 += summary.input_rows;
 859    }
 860}
 861
 862impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
 863    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 864        self.0 += summary.output_rows;
 865    }
 866}
 867
 868impl BlockDisposition {
 869    fn is_below(&self) -> bool {
 870        matches!(self, BlockDisposition::Below)
 871    }
 872}
 873
 874// Count the number of bytes prior to a target point. If the string doesn't contain the target
 875// point, return its total extent. Otherwise return the target point itself.
 876fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 877    let mut row = 0;
 878    let mut offset = 0;
 879    for (ix, line) in s.split('\n').enumerate() {
 880        if ix > 0 {
 881            row += 1;
 882            offset += 1;
 883        }
 884        if row >= target {
 885            break;
 886        }
 887        offset += line.len() as usize;
 888    }
 889    (row, offset)
 890}
 891
 892#[cfg(test)]
 893mod tests {
 894    use super::*;
 895    use crate::display_map::{fold_map::FoldMap, tab_map::TabMap, wrap_map::WrapMap};
 896    use buffer::RandomCharIter;
 897    use language::Buffer;
 898    use rand::prelude::*;
 899    use std::env;
 900
 901    #[gpui::test]
 902    fn test_offset_for_row() {
 903        assert_eq!(offset_for_row("", 0), (0, 0));
 904        assert_eq!(offset_for_row("", 1), (0, 0));
 905        assert_eq!(offset_for_row("abcd", 0), (0, 0));
 906        assert_eq!(offset_for_row("abcd", 1), (0, 4));
 907        assert_eq!(offset_for_row("\n", 0), (0, 0));
 908        assert_eq!(offset_for_row("\n", 1), (1, 1));
 909        assert_eq!(offset_for_row("abc\ndef\nghi", 0), (0, 0));
 910        assert_eq!(offset_for_row("abc\ndef\nghi", 1), (1, 4));
 911        assert_eq!(offset_for_row("abc\ndef\nghi", 2), (2, 8));
 912        assert_eq!(offset_for_row("abc\ndef\nghi", 3), (2, 11));
 913    }
 914
 915    #[gpui::test]
 916    fn test_basic_blocks(cx: &mut gpui::MutableAppContext) {
 917        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
 918        let font_id = cx
 919            .font_cache()
 920            .select_font(family_id, &Default::default())
 921            .unwrap();
 922
 923        let text = "aaa\nbbb\nccc\nddd";
 924
 925        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
 926        let (fold_map, folds_snapshot) = FoldMap::new(buffer.clone(), cx);
 927        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
 928        let (wrap_map, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, None, cx);
 929        let mut block_map = BlockMap::new(buffer.clone(), wraps_snapshot.clone());
 930
 931        let mut writer = block_map.write(wraps_snapshot.clone(), vec![], cx);
 932        writer.insert(
 933            vec![
 934                BlockProperties {
 935                    position: Point::new(1, 0),
 936                    text: "BLOCK 1",
 937                    disposition: BlockDisposition::Above,
 938                    runs: vec![],
 939                },
 940                BlockProperties {
 941                    position: Point::new(1, 2),
 942                    text: "BLOCK 2",
 943                    disposition: BlockDisposition::Above,
 944                    runs: vec![],
 945                },
 946                BlockProperties {
 947                    position: Point::new(3, 2),
 948                    text: "BLOCK 3",
 949                    disposition: BlockDisposition::Below,
 950                    runs: vec![],
 951                },
 952            ],
 953            cx,
 954        );
 955
 956        let mut snapshot = block_map.read(wraps_snapshot, vec![], cx);
 957        assert_eq!(
 958            snapshot.text(),
 959            "aaa\nBLOCK 1\nBLOCK 2\nbbb\nccc\nddd\nBLOCK 3"
 960        );
 961        assert_eq!(
 962            snapshot.to_block_point(WrapPoint::new(0, 3)),
 963            BlockPoint::new(0, 3)
 964        );
 965        assert_eq!(
 966            snapshot.to_block_point(WrapPoint::new(1, 0)),
 967            BlockPoint::new(3, 0)
 968        );
 969        assert_eq!(
 970            snapshot.to_block_point(WrapPoint::new(3, 3)),
 971            BlockPoint::new(5, 3)
 972        );
 973
 974        assert_eq!(
 975            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
 976            WrapPoint::new(0, 3)
 977        );
 978        assert_eq!(
 979            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
 980            WrapPoint::new(1, 0)
 981        );
 982        assert_eq!(
 983            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
 984            WrapPoint::new(1, 0)
 985        );
 986        assert_eq!(
 987            snapshot.to_wrap_point(BlockPoint::new(6, 0)),
 988            WrapPoint::new(3, 3)
 989        );
 990
 991        assert_eq!(
 992            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
 993            BlockPoint::new(0, 3)
 994        );
 995        assert_eq!(
 996            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
 997            BlockPoint::new(3, 0)
 998        );
 999        assert_eq!(
1000            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1001            BlockPoint::new(0, 3)
1002        );
1003        assert_eq!(
1004            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1005            BlockPoint::new(3, 0)
1006        );
1007        assert_eq!(
1008            snapshot.clip_point(BlockPoint::new(3, 0), Bias::Left),
1009            BlockPoint::new(3, 0)
1010        );
1011        assert_eq!(
1012            snapshot.clip_point(BlockPoint::new(3, 0), Bias::Right),
1013            BlockPoint::new(3, 0)
1014        );
1015        assert_eq!(
1016            snapshot.clip_point(BlockPoint::new(5, 3), Bias::Left),
1017            BlockPoint::new(5, 3)
1018        );
1019        assert_eq!(
1020            snapshot.clip_point(BlockPoint::new(5, 3), Bias::Right),
1021            BlockPoint::new(5, 3)
1022        );
1023        assert_eq!(
1024            snapshot.clip_point(BlockPoint::new(6, 0), Bias::Left),
1025            BlockPoint::new(5, 3)
1026        );
1027        assert_eq!(
1028            snapshot.clip_point(BlockPoint::new(6, 0), Bias::Right),
1029            BlockPoint::new(5, 3)
1030        );
1031
1032        assert_eq!(
1033            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1034            &[Some(0), None, None, Some(1), Some(2), Some(3), None]
1035        );
1036
1037        // Insert a line break, separating two block decorations into separate
1038        // lines.
1039        buffer.update(cx, |buffer, cx| {
1040            buffer.edit([Point::new(1, 1)..Point::new(1, 1)], "!!!\n", cx)
1041        });
1042
1043        let (folds_snapshot, fold_edits) = fold_map.read(cx);
1044        let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1045        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1046            wrap_map.sync(tabs_snapshot, tab_edits, cx)
1047        });
1048        let mut snapshot = block_map.read(wraps_snapshot, wrap_edits, cx);
1049        assert_eq!(
1050            snapshot.text(),
1051            "aaa\nBLOCK 1\nb!!!\nBLOCK 2\nbb\nccc\nddd\nBLOCK 3"
1052        );
1053    }
1054
1055    #[gpui::test]
1056    fn test_blocks_on_wrapped_lines(cx: &mut gpui::MutableAppContext) {
1057        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1058        let font_id = cx
1059            .font_cache()
1060            .select_font(family_id, &Default::default())
1061            .unwrap();
1062
1063        let text = "one two three\nfour five six\nseven eight";
1064
1065        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1066        let (_, folds_snapshot) = FoldMap::new(buffer.clone(), cx);
1067        let (_, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
1068        let (_, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, Some(60.), cx);
1069        let mut block_map = BlockMap::new(buffer.clone(), wraps_snapshot.clone());
1070
1071        let mut writer = block_map.write(wraps_snapshot.clone(), vec![], cx);
1072        writer.insert(
1073            vec![
1074                BlockProperties {
1075                    position: Point::new(1, 12),
1076                    text: "<BLOCK 1",
1077                    disposition: BlockDisposition::Above,
1078                    runs: vec![],
1079                },
1080                BlockProperties {
1081                    position: Point::new(1, 1),
1082                    text: ">BLOCK 2",
1083                    disposition: BlockDisposition::Below,
1084                    runs: vec![],
1085                },
1086            ],
1087            cx,
1088        );
1089
1090        // Blocks with an 'above' disposition go above their corresponding buffer line.
1091        // Blocks with a 'below' disposition go below their corresponding buffer line.
1092        let mut snapshot = block_map.read(wraps_snapshot, vec![], cx);
1093        assert_eq!(
1094            snapshot.text(),
1095            "one two \nthree\n<BLOCK 1\nfour five \nsix\n>BLOCK 2\nseven \neight"
1096        );
1097    }
1098
1099    #[gpui::test(iterations = 100)]
1100    fn test_random_blocks(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1101        let operations = env::var("OPERATIONS")
1102            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1103            .unwrap_or(10);
1104
1105        let wrap_width = if rng.gen_bool(0.2) {
1106            None
1107        } else {
1108            Some(rng.gen_range(0.0..=100.0))
1109        };
1110        let tab_size = 1;
1111        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1112        let font_id = cx
1113            .font_cache()
1114            .select_font(family_id, &Default::default())
1115            .unwrap();
1116        let font_size = 14.0;
1117
1118        log::info!("Wrap width: {:?}", wrap_width);
1119
1120        let buffer = cx.add_model(|cx| {
1121            let len = rng.gen_range(0..10);
1122            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1123            log::info!("initial buffer text: {:?}", text);
1124            Buffer::new(0, text, cx)
1125        });
1126        let (fold_map, folds_snapshot) = FoldMap::new(buffer.clone(), cx);
1127        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), tab_size);
1128        let (wrap_map, wraps_snapshot) =
1129            WrapMap::new(tabs_snapshot, font_id, font_size, wrap_width, cx);
1130        let mut block_map = BlockMap::new(buffer.clone(), wraps_snapshot);
1131        let mut expected_blocks = Vec::new();
1132
1133        for _ in 0..operations {
1134            match rng.gen_range(0..=100) {
1135                0..=19 => {
1136                    let wrap_width = if rng.gen_bool(0.2) {
1137                        None
1138                    } else {
1139                        Some(rng.gen_range(0.0..=100.0))
1140                    };
1141                    log::info!("Setting wrap width to {:?}", wrap_width);
1142                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1143                }
1144                20..=39 => {
1145                    let block_count = rng.gen_range(1..=1);
1146                    let block_properties = (0..block_count)
1147                        .map(|_| {
1148                            let buffer = buffer.read(cx);
1149                            let position = buffer.anchor_before(
1150                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1151                            );
1152
1153                            let len = rng.gen_range(0..10);
1154                            let mut text = Rope::from(
1155                                RandomCharIter::new(&mut rng)
1156                                    .take(len)
1157                                    .collect::<String>()
1158                                    .to_uppercase()
1159                                    .as_str(),
1160                            );
1161                            let disposition = if rng.gen() {
1162                                text.push_front("<");
1163                                BlockDisposition::Above
1164                            } else {
1165                                text.push_front(">");
1166                                BlockDisposition::Below
1167                            };
1168                            log::info!(
1169                                "inserting block {:?} {:?} with text {:?}",
1170                                disposition,
1171                                position.to_point(buffer),
1172                                text.to_string()
1173                            );
1174                            BlockProperties {
1175                                position,
1176                                text,
1177                                runs: Vec::<(usize, HighlightStyle)>::new(),
1178                                disposition,
1179                            }
1180                        })
1181                        .collect::<Vec<_>>();
1182
1183                    let (folds_snapshot, fold_edits) = fold_map.read(cx);
1184                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1185                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1186                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1187                    });
1188                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits, cx);
1189                    let block_ids = block_map.insert(block_properties.clone(), cx);
1190                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1191                        expected_blocks.push((block_id, props));
1192                    }
1193                }
1194                40..=59 if !expected_blocks.is_empty() => {
1195                    let block_count = rng.gen_range(1..=4.min(expected_blocks.len()));
1196                    let block_ids_to_remove = (0..block_count)
1197                        .map(|_| {
1198                            expected_blocks
1199                                .remove(rng.gen_range(0..expected_blocks.len()))
1200                                .0
1201                        })
1202                        .collect();
1203
1204                    let (folds_snapshot, fold_edits) = fold_map.read(cx);
1205                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1206                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1207                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1208                    });
1209                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits, cx);
1210                    block_map.remove(block_ids_to_remove, cx);
1211                }
1212                _ => {
1213                    buffer.update(cx, |buffer, _| {
1214                        buffer.randomly_edit(&mut rng, 1);
1215                        log::info!("buffer text: {:?}", buffer.text());
1216                    });
1217                }
1218            }
1219
1220            let (folds_snapshot, fold_edits) = fold_map.read(cx);
1221            let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1222            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1223                wrap_map.sync(tabs_snapshot, tab_edits, cx)
1224            });
1225            let mut blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits, cx);
1226            assert_eq!(
1227                blocks_snapshot.transforms.summary().input_rows,
1228                wraps_snapshot.max_point().row() + 1
1229            );
1230            log::info!("blocks text: {:?}", blocks_snapshot.text());
1231
1232            let buffer = buffer.read(cx);
1233            let mut sorted_blocks = expected_blocks
1234                .iter()
1235                .cloned()
1236                .map(|(id, block)| {
1237                    let mut position = block.position.to_point(buffer);
1238                    match block.disposition {
1239                        BlockDisposition::Above => {
1240                            position.column = 0;
1241                        }
1242                        BlockDisposition::Below => {
1243                            position.column = buffer.line_len(position.row);
1244                        }
1245                    };
1246                    let row = wraps_snapshot.from_point(position, Bias::Left).row();
1247                    (
1248                        id,
1249                        BlockProperties {
1250                            position: row,
1251                            text: block.text,
1252                            runs: block.runs,
1253                            disposition: block.disposition,
1254                        },
1255                    )
1256                })
1257                .collect::<Vec<_>>();
1258            sorted_blocks
1259                .sort_unstable_by_key(|(id, block)| (block.position, block.disposition, *id));
1260            let mut sorted_blocks = sorted_blocks.into_iter().peekable();
1261
1262            let mut expected_buffer_rows = Vec::new();
1263            let mut expected_text = String::new();
1264            let input_text = wraps_snapshot.text();
1265            for (row, input_line) in input_text.split('\n').enumerate() {
1266                let row = row as u32;
1267                if row > 0 {
1268                    expected_text.push('\n');
1269                }
1270
1271                let buffer_row = wraps_snapshot
1272                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1273                    .row;
1274
1275                while let Some((_, block)) = sorted_blocks.peek() {
1276                    if block.position == row && block.disposition == BlockDisposition::Above {
1277                        let text = block.text.to_string();
1278                        expected_text.push_str(&text);
1279                        expected_text.push('\n');
1280                        for _ in text.split('\n') {
1281                            expected_buffer_rows.push(None);
1282                        }
1283                        sorted_blocks.next();
1284                    } else {
1285                        break;
1286                    }
1287                }
1288
1289                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1290                expected_buffer_rows.push(if soft_wrapped { None } else { Some(buffer_row) });
1291                expected_text.push_str(input_line);
1292
1293                while let Some((_, block)) = sorted_blocks.peek() {
1294                    if block.position == row && block.disposition == BlockDisposition::Below {
1295                        let text = block.text.to_string();
1296                        expected_text.push('\n');
1297                        expected_text.push_str(&text);
1298                        for _ in text.split('\n') {
1299                            expected_buffer_rows.push(None);
1300                        }
1301                        sorted_blocks.next();
1302                    } else {
1303                        break;
1304                    }
1305                }
1306            }
1307
1308            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1309            let expected_row_count = expected_lines.len();
1310            for start_row in 0..expected_row_count {
1311                let expected_text = expected_lines[start_row..].join("\n");
1312                let actual_text = blocks_snapshot
1313                    .chunks(start_row as u32..expected_row_count as u32, false)
1314                    .map(|chunk| chunk.text)
1315                    .collect::<String>();
1316                assert_eq!(
1317                    actual_text, expected_text,
1318                    "incorrect text starting from row {}",
1319                    start_row
1320                );
1321            }
1322
1323            let mut expected_longest_rows = Vec::new();
1324            let mut longest_line_len = -1_isize;
1325            for (row, line) in expected_lines.iter().enumerate() {
1326                let row = row as u32;
1327
1328                assert_eq!(
1329                    blocks_snapshot.line_len(row),
1330                    line.len() as u32,
1331                    "invalid line len for row {}",
1332                    row
1333                );
1334
1335                let line_char_count = line.chars().count() as isize;
1336                match line_char_count.cmp(&longest_line_len) {
1337                    Ordering::Less => {}
1338                    Ordering::Equal => expected_longest_rows.push(row),
1339                    Ordering::Greater => {
1340                        longest_line_len = line_char_count;
1341                        expected_longest_rows.clear();
1342                        expected_longest_rows.push(row);
1343                    }
1344                }
1345            }
1346
1347            log::info!("getting longest row >>>>>>>>>>>>>>>>>>>>>>>>");
1348            let longest_row = blocks_snapshot.longest_row();
1349            assert!(
1350                expected_longest_rows.contains(&longest_row),
1351                "incorrect longest row {}. expected {:?} with length {}",
1352                longest_row,
1353                expected_longest_rows,
1354                longest_line_len,
1355            );
1356
1357            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1358                let wrap_point = WrapPoint::new(row, 0);
1359                let block_point = blocks_snapshot.to_block_point(wrap_point);
1360                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1361            }
1362            assert_eq!(
1363                blocks_snapshot.buffer_rows(0).collect::<Vec<_>>(),
1364                expected_buffer_rows
1365            );
1366
1367            let mut block_point = BlockPoint::new(0, 0);
1368            for c in expected_text.chars() {
1369                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1370                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1371
1372                assert_eq!(
1373                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1374                    left_point
1375                );
1376                assert_eq!(
1377                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1378                    right_point
1379                );
1380
1381                if c == '\n' {
1382                    block_point.0 += Point::new(1, 0);
1383                } else {
1384                    block_point.column += c.len_utf8() as u32;
1385                }
1386            }
1387        }
1388    }
1389}