block_map.rs

   1use super::wrap_map::{self, WrapEdit, WrapPoint, WrapSnapshot};
   2use crate::{Anchor, ToPoint as _};
   3use collections::{HashMap, HashSet};
   4use gpui::{AppContext, ElementBox};
   5use language::Chunk;
   6use parking_lot::Mutex;
   7use std::{
   8    cmp::{self, Ordering, Reverse},
   9    fmt::Debug,
  10    ops::{Deref, Range},
  11    sync::{
  12        atomic::{AtomicUsize, Ordering::SeqCst},
  13        Arc,
  14    },
  15};
  16use sum_tree::{Bias, SumTree};
  17use text::{Edit, Point};
  18use theme::SyntaxTheme;
  19
  20const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  21
  22pub struct BlockMap {
  23    next_block_id: AtomicUsize,
  24    wrap_snapshot: Mutex<WrapSnapshot>,
  25    blocks: Vec<Arc<Block>>,
  26    transforms: Mutex<SumTree<Transform>>,
  27}
  28
  29pub struct BlockMapWriter<'a>(&'a mut BlockMap);
  30
  31pub struct BlockSnapshot {
  32    wrap_snapshot: WrapSnapshot,
  33    transforms: SumTree<Transform>,
  34}
  35
  36#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
  37pub struct BlockId(usize);
  38
  39#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  40pub struct BlockPoint(pub super::Point);
  41
  42#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  43struct BlockRow(u32);
  44
  45#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  46struct WrapRow(u32);
  47
  48pub type RenderBlock = Arc<dyn Fn(&BlockContext) -> ElementBox>;
  49
  50pub struct Block {
  51    id: BlockId,
  52    position: Anchor,
  53    height: u8,
  54    render: Mutex<RenderBlock>,
  55    disposition: BlockDisposition,
  56}
  57
  58#[derive(Clone)]
  59pub struct BlockProperties<P>
  60where
  61    P: Clone,
  62{
  63    pub position: P,
  64    pub height: u8,
  65    pub render: Arc<dyn Fn(&BlockContext) -> ElementBox>,
  66    pub disposition: BlockDisposition,
  67}
  68
  69pub struct BlockContext<'a> {
  70    pub cx: &'a AppContext,
  71    pub anchor_x: f32,
  72    pub gutter_width: f32,
  73    pub gutter_padding: f32,
  74    pub em_width: f32,
  75    pub line_height: f32,
  76}
  77
  78#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
  79pub enum BlockDisposition {
  80    Above,
  81    Below,
  82}
  83
  84#[derive(Clone, Debug)]
  85struct Transform {
  86    summary: TransformSummary,
  87    block: Option<AlignedBlock>,
  88}
  89
  90#[derive(Clone, Debug)]
  91pub struct AlignedBlock {
  92    block: Arc<Block>,
  93    column: u32,
  94}
  95
  96#[derive(Clone, Debug, Default)]
  97struct TransformSummary {
  98    input_rows: u32,
  99    output_rows: u32,
 100}
 101
 102pub struct BlockChunks<'a> {
 103    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 104    input_chunks: wrap_map::WrapChunks<'a>,
 105    input_chunk: Chunk<'a>,
 106    output_row: u32,
 107    max_output_row: u32,
 108}
 109
 110pub struct BlockBufferRows<'a> {
 111    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 112    input_buffer_rows: wrap_map::WrapBufferRows<'a>,
 113    output_row: u32,
 114    started: bool,
 115}
 116
 117impl BlockMap {
 118    pub fn new(wrap_snapshot: WrapSnapshot) -> Self {
 119        Self {
 120            next_block_id: AtomicUsize::new(0),
 121            blocks: Vec::new(),
 122            transforms: Mutex::new(SumTree::from_item(
 123                Transform::isomorphic(wrap_snapshot.text_summary().lines.row + 1),
 124                &(),
 125            )),
 126            wrap_snapshot: Mutex::new(wrap_snapshot),
 127        }
 128    }
 129
 130    pub fn read(&self, wrap_snapshot: WrapSnapshot, edits: Vec<WrapEdit>) -> BlockSnapshot {
 131        self.sync(&wrap_snapshot, edits);
 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(&mut self, wrap_snapshot: WrapSnapshot, edits: Vec<WrapEdit>) -> BlockMapWriter {
 140        self.sync(&wrap_snapshot, edits);
 141        *self.wrap_snapshot.lock() = wrap_snapshot;
 142        BlockMapWriter(self)
 143    }
 144
 145    fn sync(&self, wrap_snapshot: &WrapSnapshot, edits: Vec<WrapEdit>) {
 146        if edits.is_empty() {
 147            return;
 148        }
 149
 150        let buffer = wrap_snapshot.buffer_snapshot();
 151        let mut transforms = self.transforms.lock();
 152        let mut new_transforms = SumTree::new();
 153        let old_row_count = transforms.summary().input_rows;
 154        let new_row_count = wrap_snapshot.max_point().row() + 1;
 155        let mut cursor = transforms.cursor::<WrapRow>();
 156        let mut last_block_ix = 0;
 157        let mut blocks_in_edit = Vec::new();
 158        let mut edits = edits.into_iter().peekable();
 159
 160        while let Some(edit) = edits.next() {
 161            // Preserve any old transforms that precede this edit.
 162            let old_start = WrapRow(edit.old.start);
 163            let new_start = WrapRow(edit.new.start);
 164            new_transforms.push_tree(cursor.slice(&old_start, Bias::Left, &()), &());
 165            if let Some(transform) = cursor.item() {
 166                if transform.is_isomorphic() && old_start == cursor.end(&()) {
 167                    new_transforms.push(transform.clone(), &());
 168                    cursor.next(&());
 169                    while let Some(transform) = cursor.item() {
 170                        if transform
 171                            .block
 172                            .as_ref()
 173                            .map_or(false, |b| b.disposition.is_below())
 174                        {
 175                            new_transforms.push(transform.clone(), &());
 176                            cursor.next(&());
 177                        } else {
 178                            break;
 179                        }
 180                    }
 181                }
 182            }
 183
 184            // Preserve any portion of an old transform that precedes this edit.
 185            let extent_before_edit = old_start.0 - cursor.start().0;
 186            push_isomorphic(&mut new_transforms, extent_before_edit);
 187
 188            // Skip over any old transforms that intersect this edit.
 189            let mut old_end = WrapRow(edit.old.end);
 190            let mut new_end = WrapRow(edit.new.end);
 191            cursor.seek(&old_end, Bias::Left, &());
 192            cursor.next(&());
 193            if old_end == *cursor.start() {
 194                while let Some(transform) = cursor.item() {
 195                    if transform
 196                        .block
 197                        .as_ref()
 198                        .map_or(false, |b| b.disposition.is_below())
 199                    {
 200                        cursor.next(&());
 201                    } else {
 202                        break;
 203                    }
 204                }
 205            }
 206
 207            // Combine this edit with any subsequent edits that intersect the same transform.
 208            while let Some(next_edit) = edits.peek() {
 209                if next_edit.old.start <= cursor.start().0 {
 210                    old_end = WrapRow(next_edit.old.end);
 211                    new_end = WrapRow(next_edit.new.end);
 212                    cursor.seek(&old_end, Bias::Left, &());
 213                    cursor.next(&());
 214                    if old_end == *cursor.start() {
 215                        while let Some(transform) = cursor.item() {
 216                            if transform
 217                                .block
 218                                .as_ref()
 219                                .map_or(false, |b| b.disposition.is_below())
 220                            {
 221                                cursor.next(&());
 222                            } else {
 223                                break;
 224                            }
 225                        }
 226                    }
 227                    edits.next();
 228                } else {
 229                    break;
 230                }
 231            }
 232
 233            // Find the blocks within this edited region.
 234            let new_buffer_start =
 235                wrap_snapshot.to_point(WrapPoint::new(new_start.0, 0), Bias::Left);
 236            let start_anchor = buffer.anchor_before(new_buffer_start);
 237            let start_block_ix = match self.blocks[last_block_ix..].binary_search_by(|probe| {
 238                probe
 239                    .position
 240                    .cmp(&start_anchor, &buffer)
 241                    .unwrap()
 242                    .then(Ordering::Greater)
 243            }) {
 244                Ok(ix) | Err(ix) => last_block_ix + ix,
 245            };
 246
 247            let end_block_ix = if new_end.0 > wrap_snapshot.max_point().row() {
 248                self.blocks.len()
 249            } else {
 250                let new_buffer_end =
 251                    wrap_snapshot.to_point(WrapPoint::new(new_end.0, 0), Bias::Left);
 252                let end_anchor = buffer.anchor_before(new_buffer_end);
 253                match self.blocks[start_block_ix..].binary_search_by(|probe| {
 254                    probe
 255                        .position
 256                        .cmp(&end_anchor, &buffer)
 257                        .unwrap()
 258                        .then(Ordering::Greater)
 259                }) {
 260                    Ok(ix) | Err(ix) => start_block_ix + ix,
 261                }
 262            };
 263            last_block_ix = end_block_ix;
 264
 265            debug_assert!(blocks_in_edit.is_empty());
 266            blocks_in_edit.extend(
 267                self.blocks[start_block_ix..end_block_ix]
 268                    .iter()
 269                    .map(|block| {
 270                        let mut position = block.position.to_point(&buffer);
 271                        let column = wrap_snapshot.from_point(position, Bias::Left).column();
 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(), column, block.clone())
 280                    }),
 281            );
 282
 283            // When multiple blocks are on the same row, newer blocks appear above older
 284            // blocks. This is arbitrary, but we currently rely on it in ProjectDiagnosticsEditor.
 285            blocks_in_edit
 286                .sort_by_key(|(row, _, block)| (*row, block.disposition, Reverse(block.id)));
 287
 288            // For each of these blocks, insert a new isomorphic transform preceding the block,
 289            // and then insert the block itself.
 290            for (block_row, column, block) in blocks_in_edit.drain(..) {
 291                let insertion_row = match block.disposition {
 292                    BlockDisposition::Above => block_row,
 293                    BlockDisposition::Below => block_row + 1,
 294                };
 295                let extent_before_block = insertion_row - new_transforms.summary().input_rows;
 296                push_isomorphic(&mut new_transforms, extent_before_block);
 297                new_transforms.push(Transform::block(block, column), &());
 298            }
 299
 300            old_end = WrapRow(old_end.0.min(old_row_count));
 301            new_end = WrapRow(new_end.0.min(new_row_count));
 302
 303            // Insert an isomorphic transform after the final block.
 304            let extent_after_last_block = new_end.0 - new_transforms.summary().input_rows;
 305            push_isomorphic(&mut new_transforms, extent_after_last_block);
 306
 307            // Preserve any portion of the old transform after this edit.
 308            let extent_after_edit = cursor.start().0 - old_end.0;
 309            push_isomorphic(&mut new_transforms, extent_after_edit);
 310        }
 311
 312        new_transforms.push_tree(cursor.suffix(&()), &());
 313        debug_assert_eq!(
 314            new_transforms.summary().input_rows,
 315            wrap_snapshot.max_point().row() + 1
 316        );
 317
 318        drop(cursor);
 319        *transforms = new_transforms;
 320    }
 321
 322    pub fn replace(&mut self, mut renderers: HashMap<BlockId, RenderBlock>) {
 323        for block in &self.blocks {
 324            if let Some(render) = renderers.remove(&block.id) {
 325                *block.render.lock() = render;
 326            }
 327        }
 328    }
 329}
 330
 331fn push_isomorphic(tree: &mut SumTree<Transform>, rows: u32) {
 332    if rows == 0 {
 333        return;
 334    }
 335
 336    let mut extent = Some(rows);
 337    tree.update_last(
 338        |last_transform| {
 339            if last_transform.is_isomorphic() {
 340                let extent = extent.take().unwrap();
 341                last_transform.summary.input_rows += extent;
 342                last_transform.summary.output_rows += extent;
 343            }
 344        },
 345        &(),
 346    );
 347    if let Some(extent) = extent {
 348        tree.push(Transform::isomorphic(extent), &());
 349    }
 350}
 351
 352impl BlockPoint {
 353    pub fn new(row: u32, column: u32) -> Self {
 354        Self(Point::new(row, column))
 355    }
 356}
 357
 358impl Deref for BlockPoint {
 359    type Target = Point;
 360
 361    fn deref(&self) -> &Self::Target {
 362        &self.0
 363    }
 364}
 365
 366impl std::ops::DerefMut for BlockPoint {
 367    fn deref_mut(&mut self) -> &mut Self::Target {
 368        &mut self.0
 369    }
 370}
 371
 372impl<'a> BlockMapWriter<'a> {
 373    pub fn insert(
 374        &mut self,
 375        blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
 376    ) -> Vec<BlockId> {
 377        let mut ids = Vec::new();
 378        let mut edits = Vec::<Edit<u32>>::new();
 379        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 380        let buffer = wrap_snapshot.buffer_snapshot();
 381
 382        for block in blocks {
 383            let id = BlockId(self.0.next_block_id.fetch_add(1, SeqCst));
 384            ids.push(id);
 385
 386            let position = block.position;
 387            let point = position.to_point(&buffer);
 388            let wrap_row = wrap_snapshot
 389                .from_point(Point::new(point.row, 0), Bias::Left)
 390                .row();
 391            let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 392            let end_row = wrap_snapshot
 393                .next_row_boundary(WrapPoint::new(wrap_row, 0))
 394                .unwrap_or(wrap_snapshot.max_point().row() + 1);
 395
 396            let block_ix = match self
 397                .0
 398                .blocks
 399                .binary_search_by(|probe| probe.position.cmp(&position, &buffer).unwrap())
 400            {
 401                Ok(ix) | Err(ix) => ix,
 402            };
 403            self.0.blocks.insert(
 404                block_ix,
 405                Arc::new(Block {
 406                    id,
 407                    position,
 408                    height: block.height,
 409                    render: Mutex::new(block.render),
 410                    disposition: block.disposition,
 411                }),
 412            );
 413
 414            if let Err(edit_ix) = edits.binary_search_by_key(&start_row, |edit| edit.old.start) {
 415                edits.insert(
 416                    edit_ix,
 417                    Edit {
 418                        old: start_row..end_row,
 419                        new: start_row..end_row,
 420                    },
 421                );
 422            }
 423        }
 424
 425        self.0.sync(wrap_snapshot, edits);
 426        ids
 427    }
 428
 429    pub fn remove(&mut self, block_ids: HashSet<BlockId>) {
 430        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 431        let buffer = wrap_snapshot.buffer_snapshot();
 432        let mut edits = Vec::new();
 433        let mut last_block_buffer_row = None;
 434        self.0.blocks.retain(|block| {
 435            if block_ids.contains(&block.id) {
 436                let buffer_row = block.position.to_point(&buffer).row;
 437                if last_block_buffer_row != Some(buffer_row) {
 438                    last_block_buffer_row = Some(buffer_row);
 439                    let wrap_row = wrap_snapshot
 440                        .from_point(Point::new(buffer_row, 0), Bias::Left)
 441                        .row();
 442                    let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 443                    let end_row = wrap_snapshot
 444                        .next_row_boundary(WrapPoint::new(wrap_row, 0))
 445                        .unwrap_or(wrap_snapshot.max_point().row() + 1);
 446                    edits.push(Edit {
 447                        old: start_row..end_row,
 448                        new: start_row..end_row,
 449                    })
 450                }
 451                false
 452            } else {
 453                true
 454            }
 455        });
 456        self.0.sync(wrap_snapshot, edits);
 457    }
 458}
 459
 460impl BlockSnapshot {
 461    #[cfg(test)]
 462    pub fn text(&self) -> String {
 463        self.chunks(0..self.transforms.summary().output_rows, None)
 464            .map(|chunk| chunk.text)
 465            .collect()
 466    }
 467
 468    pub fn chunks<'a>(
 469        &'a self,
 470        rows: Range<u32>,
 471        theme: Option<&'a SyntaxTheme>,
 472    ) -> BlockChunks<'a> {
 473        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 474        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 475        let input_end = {
 476            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 477            let overshoot = if cursor
 478                .item()
 479                .map_or(false, |transform| transform.is_isomorphic())
 480            {
 481                rows.end - cursor.start().0 .0
 482            } else {
 483                0
 484            };
 485            cursor.start().1 .0 + overshoot
 486        };
 487        let input_start = {
 488            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 489            let overshoot = if cursor
 490                .item()
 491                .map_or(false, |transform| transform.is_isomorphic())
 492            {
 493                rows.start - cursor.start().0 .0
 494            } else {
 495                0
 496            };
 497            cursor.start().1 .0 + overshoot
 498        };
 499        BlockChunks {
 500            input_chunks: self.wrap_snapshot.chunks(input_start..input_end, theme),
 501            input_chunk: Default::default(),
 502            transforms: cursor,
 503            output_row: rows.start,
 504            max_output_row,
 505        }
 506    }
 507
 508    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> BlockBufferRows<'a> {
 509        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 510        cursor.seek(&BlockRow(start_row), Bias::Right, &());
 511        let (output_start, input_start) = cursor.start();
 512        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 513            start_row - output_start.0
 514        } else {
 515            0
 516        };
 517        let input_start_row = input_start.0 + overshoot;
 518        BlockBufferRows {
 519            transforms: cursor,
 520            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 521            output_row: start_row,
 522            started: false,
 523        }
 524    }
 525
 526    pub fn blocks_in_range<'a>(
 527        &'a self,
 528        rows: Range<u32>,
 529    ) -> impl Iterator<Item = (u32, &'a AlignedBlock)> {
 530        let mut cursor = self.transforms.cursor::<BlockRow>();
 531        cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 532        std::iter::from_fn(move || {
 533            while let Some(transform) = cursor.item() {
 534                let start_row = cursor.start().0;
 535                if start_row >= rows.end {
 536                    break;
 537                }
 538                if let Some(block) = &transform.block {
 539                    cursor.next(&());
 540                    return Some((start_row, block));
 541                } else {
 542                    cursor.next(&());
 543                }
 544            }
 545            None
 546        })
 547    }
 548
 549    pub fn max_point(&self) -> BlockPoint {
 550        let row = self.transforms.summary().output_rows - 1;
 551        BlockPoint::new(row, self.line_len(row))
 552    }
 553
 554    pub fn longest_row(&self) -> u32 {
 555        let input_row = self.wrap_snapshot.longest_row();
 556        self.to_block_point(WrapPoint::new(input_row, 0)).row
 557    }
 558
 559    pub fn line_len(&self, row: u32) -> u32 {
 560        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 561        cursor.seek(&BlockRow(row), Bias::Right, &());
 562        if let Some(transform) = cursor.item() {
 563            let (output_start, input_start) = cursor.start();
 564            let overshoot = row - output_start.0;
 565            if transform.block.is_some() {
 566                0
 567            } else {
 568                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 569            }
 570        } else {
 571            panic!("row out of range");
 572        }
 573    }
 574
 575    pub fn is_block_line(&self, row: u32) -> bool {
 576        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 577        cursor.seek(&BlockRow(row), Bias::Right, &());
 578        cursor.item().map_or(false, |t| t.block.is_some())
 579    }
 580
 581    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 582        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 583        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 584
 585        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 586        let mut search_left =
 587            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 588        let mut reversed = false;
 589
 590        loop {
 591            if let Some(transform) = cursor.item() {
 592                if transform.is_isomorphic() {
 593                    let (output_start_row, input_start_row) = cursor.start();
 594                    let (output_end_row, input_end_row) = cursor.end(&());
 595                    let output_start = Point::new(output_start_row.0, 0);
 596                    let input_start = Point::new(input_start_row.0, 0);
 597                    let input_end = Point::new(input_end_row.0, 0);
 598                    let input_point = if point.row >= output_end_row.0 {
 599                        let line_len = self.wrap_snapshot.line_len(input_end_row.0 - 1);
 600                        self.wrap_snapshot
 601                            .clip_point(WrapPoint::new(input_end_row.0 - 1, line_len), bias)
 602                    } else {
 603                        let output_overshoot = point.0.saturating_sub(output_start);
 604                        self.wrap_snapshot
 605                            .clip_point(WrapPoint(input_start + output_overshoot), bias)
 606                    };
 607
 608                    if (input_start..input_end).contains(&input_point.0) {
 609                        let input_overshoot = input_point.0.saturating_sub(input_start);
 610                        return BlockPoint(output_start + input_overshoot);
 611                    }
 612                }
 613
 614                if search_left {
 615                    cursor.prev(&());
 616                } else {
 617                    cursor.next(&());
 618                }
 619            } else if reversed {
 620                return self.max_point();
 621            } else {
 622                reversed = true;
 623                search_left = !search_left;
 624                cursor.seek(&BlockRow(point.row), Bias::Right, &());
 625            }
 626        }
 627    }
 628
 629    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 630        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 631        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 632        if let Some(transform) = cursor.item() {
 633            debug_assert!(transform.is_isomorphic());
 634        } else {
 635            return self.max_point();
 636        }
 637
 638        let (input_start_row, output_start_row) = cursor.start();
 639        let input_start = Point::new(input_start_row.0, 0);
 640        let output_start = Point::new(output_start_row.0, 0);
 641        let input_overshoot = wrap_point.0 - input_start;
 642        BlockPoint(output_start + input_overshoot)
 643    }
 644
 645    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 646        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 647        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 648        if let Some(transform) = cursor.item() {
 649            match transform.block.as_ref().map(|b| b.disposition) {
 650                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 651                Some(BlockDisposition::Below) => {
 652                    let wrap_row = cursor.start().1 .0 - 1;
 653                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
 654                }
 655                None => {
 656                    let overshoot = block_point.row - cursor.start().0 .0;
 657                    let wrap_row = cursor.start().1 .0 + overshoot;
 658                    WrapPoint::new(wrap_row, block_point.column)
 659                }
 660            }
 661        } else {
 662            self.wrap_snapshot.max_point()
 663        }
 664    }
 665}
 666
 667impl Transform {
 668    fn isomorphic(rows: u32) -> Self {
 669        Self {
 670            summary: TransformSummary {
 671                input_rows: rows,
 672                output_rows: rows,
 673            },
 674            block: None,
 675        }
 676    }
 677
 678    fn block(block: Arc<Block>, column: u32) -> Self {
 679        Self {
 680            summary: TransformSummary {
 681                input_rows: 0,
 682                output_rows: block.height as u32,
 683            },
 684            block: Some(AlignedBlock { block, column }),
 685        }
 686    }
 687
 688    fn is_isomorphic(&self) -> bool {
 689        self.block.is_none()
 690    }
 691}
 692
 693impl<'a> Iterator for BlockChunks<'a> {
 694    type Item = Chunk<'a>;
 695
 696    fn next(&mut self) -> Option<Self::Item> {
 697        if self.output_row >= self.max_output_row {
 698            return None;
 699        }
 700
 701        let transform = self.transforms.item()?;
 702        if transform.block.is_some() {
 703            let block_start = self.transforms.start().0 .0;
 704            let mut block_end = self.transforms.end(&()).0 .0;
 705            self.transforms.next(&());
 706            if self.transforms.item().is_none() {
 707                block_end -= 1;
 708            }
 709
 710            let start_in_block = self.output_row - block_start;
 711            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
 712            let line_count = end_in_block - start_in_block;
 713            self.output_row += line_count;
 714
 715            return Some(Chunk {
 716                text: unsafe { std::str::from_utf8_unchecked(&NEWLINES[..line_count as usize]) },
 717                highlight_style: None,
 718                diagnostic: None,
 719            });
 720        }
 721
 722        if self.input_chunk.text.is_empty() {
 723            if let Some(input_chunk) = self.input_chunks.next() {
 724                self.input_chunk = input_chunk;
 725            } else {
 726                self.output_row += 1;
 727                if self.output_row < self.max_output_row {
 728                    self.transforms.next(&());
 729                    return Some(Chunk {
 730                        text: "\n",
 731                        ..Default::default()
 732                    });
 733                } else {
 734                    return None;
 735                }
 736            }
 737        }
 738
 739        let transform_end = self.transforms.end(&()).0 .0;
 740        let (prefix_rows, prefix_bytes) =
 741            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
 742        self.output_row += prefix_rows;
 743        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
 744        self.input_chunk.text = suffix;
 745        if self.output_row == transform_end {
 746            self.transforms.next(&());
 747        }
 748
 749        Some(Chunk {
 750            text: prefix,
 751            ..self.input_chunk
 752        })
 753    }
 754}
 755
 756impl<'a> Iterator for BlockBufferRows<'a> {
 757    type Item = Option<u32>;
 758
 759    fn next(&mut self) -> Option<Self::Item> {
 760        if self.started {
 761            self.output_row += 1;
 762        } else {
 763            self.started = true;
 764        }
 765
 766        if self.output_row >= self.transforms.end(&()).0 .0 {
 767            self.transforms.next(&());
 768        }
 769
 770        let transform = self.transforms.item()?;
 771        if transform.block.is_some() {
 772            Some(None)
 773        } else {
 774            Some(self.input_buffer_rows.next().unwrap())
 775        }
 776    }
 777}
 778
 779impl sum_tree::Item for Transform {
 780    type Summary = TransformSummary;
 781
 782    fn summary(&self) -> Self::Summary {
 783        self.summary.clone()
 784    }
 785}
 786
 787impl sum_tree::Summary for TransformSummary {
 788    type Context = ();
 789
 790    fn add_summary(&mut self, summary: &Self, _: &()) {
 791        self.input_rows += summary.input_rows;
 792        self.output_rows += summary.output_rows;
 793    }
 794}
 795
 796impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
 797    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 798        self.0 += summary.input_rows;
 799    }
 800}
 801
 802impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
 803    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 804        self.0 += summary.output_rows;
 805    }
 806}
 807
 808impl BlockDisposition {
 809    fn is_below(&self) -> bool {
 810        matches!(self, BlockDisposition::Below)
 811    }
 812}
 813
 814impl AlignedBlock {
 815    pub fn height(&self) -> u32 {
 816        self.height as u32
 817    }
 818
 819    pub fn column(&self) -> u32 {
 820        self.column
 821    }
 822
 823    pub fn render(&self, cx: &BlockContext) -> ElementBox {
 824        self.render.lock()(cx)
 825    }
 826
 827    pub fn position(&self) -> &Anchor {
 828        &self.block.position
 829    }
 830}
 831
 832impl Deref for AlignedBlock {
 833    type Target = Block;
 834
 835    fn deref(&self) -> &Self::Target {
 836        self.block.as_ref()
 837    }
 838}
 839
 840impl<'a> Deref for BlockContext<'a> {
 841    type Target = AppContext;
 842
 843    fn deref(&self) -> &Self::Target {
 844        &self.cx
 845    }
 846}
 847
 848impl Debug for Block {
 849    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 850        f.debug_struct("Block")
 851            .field("id", &self.id)
 852            .field("position", &self.position)
 853            .field("disposition", &self.disposition)
 854            .finish()
 855    }
 856}
 857
 858// Count the number of bytes prior to a target point. If the string doesn't contain the target
 859// point, return its total extent. Otherwise return the target point itself.
 860fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 861    let mut row = 0;
 862    let mut offset = 0;
 863    for (ix, line) in s.split('\n').enumerate() {
 864        if ix > 0 {
 865            row += 1;
 866            offset += 1;
 867        }
 868        if row >= target {
 869            break;
 870        }
 871        offset += line.len() as usize;
 872    }
 873    (row, offset)
 874}
 875
 876#[cfg(test)]
 877mod tests {
 878    use super::*;
 879    use crate::display_map::{fold_map::FoldMap, tab_map::TabMap, wrap_map::WrapMap};
 880    use crate::multi_buffer::MultiBuffer;
 881    use gpui::{elements::Empty, Element};
 882    use rand::prelude::*;
 883    use std::env;
 884    use text::RandomCharIter;
 885
 886    #[gpui::test]
 887    fn test_offset_for_row() {
 888        assert_eq!(offset_for_row("", 0), (0, 0));
 889        assert_eq!(offset_for_row("", 1), (0, 0));
 890        assert_eq!(offset_for_row("abcd", 0), (0, 0));
 891        assert_eq!(offset_for_row("abcd", 1), (0, 4));
 892        assert_eq!(offset_for_row("\n", 0), (0, 0));
 893        assert_eq!(offset_for_row("\n", 1), (1, 1));
 894        assert_eq!(offset_for_row("abc\ndef\nghi", 0), (0, 0));
 895        assert_eq!(offset_for_row("abc\ndef\nghi", 1), (1, 4));
 896        assert_eq!(offset_for_row("abc\ndef\nghi", 2), (2, 8));
 897        assert_eq!(offset_for_row("abc\ndef\nghi", 3), (2, 11));
 898    }
 899
 900    #[gpui::test]
 901    fn test_basic_blocks(cx: &mut gpui::MutableAppContext) {
 902        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
 903        let font_id = cx
 904            .font_cache()
 905            .select_font(family_id, &Default::default())
 906            .unwrap();
 907
 908        let text = "aaa\nbbb\nccc\nddd";
 909
 910        let buffer = MultiBuffer::build_simple(text, cx);
 911        let buffer_snapshot = buffer.read(cx).snapshot(cx);
 912        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
 913        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
 914        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
 915        let (wrap_map, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, None, cx);
 916        let mut block_map = BlockMap::new(wraps_snapshot.clone());
 917
 918        let mut writer = block_map.write(wraps_snapshot.clone(), vec![]);
 919        writer.insert(vec![
 920            BlockProperties {
 921                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
 922                height: 1,
 923                disposition: BlockDisposition::Above,
 924                render: Arc::new(|_| Empty::new().named("block 1")),
 925            },
 926            BlockProperties {
 927                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
 928                height: 2,
 929                disposition: BlockDisposition::Above,
 930                render: Arc::new(|_| Empty::new().named("block 2")),
 931            },
 932            BlockProperties {
 933                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
 934                height: 3,
 935                disposition: BlockDisposition::Below,
 936                render: Arc::new(|_| Empty::new().named("block 3")),
 937            },
 938        ]);
 939
 940        let snapshot = block_map.read(wraps_snapshot, vec![]);
 941        assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
 942
 943        let blocks = snapshot
 944            .blocks_in_range(0..8)
 945            .map(|(start_row, block)| {
 946                (
 947                    start_row..start_row + block.height(),
 948                    block.column(),
 949                    block
 950                        .render(&BlockContext {
 951                            cx,
 952                            anchor_x: 0.,
 953                            gutter_padding: 0.,
 954                            gutter_width: 0.,
 955                            line_height: 0.,
 956                            em_width: 0.,
 957                        })
 958                        .name()
 959                        .unwrap()
 960                        .to_string(),
 961                )
 962            })
 963            .collect::<Vec<_>>();
 964
 965        // When multiple blocks are on the same line, the newer blocks appear first.
 966        assert_eq!(
 967            blocks,
 968            &[
 969                (1..3, 2, "block 2".to_string()),
 970                (3..4, 0, "block 1".to_string()),
 971                (7..10, 3, "block 3".to_string()),
 972            ]
 973        );
 974
 975        assert_eq!(
 976            snapshot.to_block_point(WrapPoint::new(0, 3)),
 977            BlockPoint::new(0, 3)
 978        );
 979        assert_eq!(
 980            snapshot.to_block_point(WrapPoint::new(1, 0)),
 981            BlockPoint::new(4, 0)
 982        );
 983        assert_eq!(
 984            snapshot.to_block_point(WrapPoint::new(3, 3)),
 985            BlockPoint::new(6, 3)
 986        );
 987
 988        assert_eq!(
 989            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
 990            WrapPoint::new(0, 3)
 991        );
 992        assert_eq!(
 993            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
 994            WrapPoint::new(1, 0)
 995        );
 996        assert_eq!(
 997            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
 998            WrapPoint::new(1, 0)
 999        );
1000        assert_eq!(
1001            snapshot.to_wrap_point(BlockPoint::new(7, 0)),
1002            WrapPoint::new(3, 3)
1003        );
1004
1005        assert_eq!(
1006            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
1007            BlockPoint::new(0, 3)
1008        );
1009        assert_eq!(
1010            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
1011            BlockPoint::new(4, 0)
1012        );
1013        assert_eq!(
1014            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1015            BlockPoint::new(0, 3)
1016        );
1017        assert_eq!(
1018            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1019            BlockPoint::new(4, 0)
1020        );
1021        assert_eq!(
1022            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Left),
1023            BlockPoint::new(4, 0)
1024        );
1025        assert_eq!(
1026            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Right),
1027            BlockPoint::new(4, 0)
1028        );
1029        assert_eq!(
1030            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Left),
1031            BlockPoint::new(6, 3)
1032        );
1033        assert_eq!(
1034            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Right),
1035            BlockPoint::new(6, 3)
1036        );
1037        assert_eq!(
1038            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Left),
1039            BlockPoint::new(6, 3)
1040        );
1041        assert_eq!(
1042            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Right),
1043            BlockPoint::new(6, 3)
1044        );
1045
1046        assert_eq!(
1047            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1048            &[
1049                Some(0),
1050                None,
1051                None,
1052                None,
1053                Some(1),
1054                Some(2),
1055                Some(3),
1056                None,
1057                None,
1058                None
1059            ]
1060        );
1061
1062        // Insert a line break, separating two block decorations into separate lines.
1063        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1064            buffer.edit([Point::new(1, 1)..Point::new(1, 1)], "!!!\n", cx);
1065            buffer.snapshot(cx)
1066        });
1067
1068        let (folds_snapshot, fold_edits) =
1069            fold_map.read(buffer_snapshot, subscription.consume().into_inner());
1070        let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1071        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1072            wrap_map.sync(tabs_snapshot, tab_edits, cx)
1073        });
1074        let snapshot = block_map.read(wraps_snapshot, wrap_edits);
1075        assert_eq!(snapshot.text(), "aaa\n\nb!!!\n\n\nbb\nccc\nddd\n\n\n");
1076    }
1077
1078    #[gpui::test]
1079    fn test_blocks_on_wrapped_lines(cx: &mut gpui::MutableAppContext) {
1080        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1081        let font_id = cx
1082            .font_cache()
1083            .select_font(family_id, &Default::default())
1084            .unwrap();
1085
1086        let text = "one two three\nfour five six\nseven eight";
1087
1088        let buffer = MultiBuffer::build_simple(text, cx);
1089        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1090        let (_, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1091        let (_, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
1092        let (_, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, Some(60.), cx);
1093        let mut block_map = BlockMap::new(wraps_snapshot.clone());
1094
1095        let mut writer = block_map.write(wraps_snapshot.clone(), vec![]);
1096        writer.insert(vec![
1097            BlockProperties {
1098                position: buffer_snapshot.anchor_after(Point::new(1, 12)),
1099                disposition: BlockDisposition::Above,
1100                render: Arc::new(|_| Empty::new().named("block 1")),
1101                height: 1,
1102            },
1103            BlockProperties {
1104                position: buffer_snapshot.anchor_after(Point::new(1, 1)),
1105                disposition: BlockDisposition::Below,
1106                render: Arc::new(|_| Empty::new().named("block 2")),
1107                height: 1,
1108            },
1109        ]);
1110
1111        // Blocks with an 'above' disposition go above their corresponding buffer line.
1112        // Blocks with a 'below' disposition go below their corresponding buffer line.
1113        let snapshot = block_map.read(wraps_snapshot, vec![]);
1114        assert_eq!(
1115            snapshot.text(),
1116            "one two \nthree\n\nfour five \nsix\n\nseven \neight"
1117        );
1118    }
1119
1120    #[gpui::test(iterations = 100)]
1121    fn test_random_blocks(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1122        let operations = env::var("OPERATIONS")
1123            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1124            .unwrap_or(10);
1125
1126        let wrap_width = if rng.gen_bool(0.2) {
1127            None
1128        } else {
1129            Some(rng.gen_range(0.0..=100.0))
1130        };
1131        let tab_size = 1;
1132        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1133        let font_id = cx
1134            .font_cache()
1135            .select_font(family_id, &Default::default())
1136            .unwrap();
1137        let font_size = 14.0;
1138
1139        log::info!("Wrap width: {:?}", wrap_width);
1140
1141        let buffer = if rng.gen() {
1142            let len = rng.gen_range(0..10);
1143            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1144            log::info!("initial buffer text: {:?}", text);
1145            MultiBuffer::build_simple(&text, cx)
1146        } else {
1147            MultiBuffer::build_random(&mut rng, cx)
1148        };
1149
1150        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1151        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1152        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), tab_size);
1153        let (wrap_map, wraps_snapshot) =
1154            WrapMap::new(tabs_snapshot, font_id, font_size, wrap_width, cx);
1155        let mut block_map = BlockMap::new(wraps_snapshot);
1156        let mut expected_blocks = Vec::new();
1157
1158        for _ in 0..operations {
1159            let mut buffer_edits = Vec::new();
1160            match rng.gen_range(0..=100) {
1161                0..=19 => {
1162                    let wrap_width = if rng.gen_bool(0.2) {
1163                        None
1164                    } else {
1165                        Some(rng.gen_range(0.0..=100.0))
1166                    };
1167                    log::info!("Setting wrap width to {:?}", wrap_width);
1168                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1169                }
1170                20..=39 => {
1171                    let block_count = rng.gen_range(1..=5);
1172                    let block_properties = (0..block_count)
1173                        .map(|_| {
1174                            let buffer = buffer.read(cx).read(cx);
1175                            let position = buffer.anchor_after(
1176                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1177                            );
1178
1179                            let disposition = if rng.gen() {
1180                                BlockDisposition::Above
1181                            } else {
1182                                BlockDisposition::Below
1183                            };
1184                            let height = rng.gen_range(1..5);
1185                            log::info!(
1186                                "inserting block {:?} {:?} with height {}",
1187                                disposition,
1188                                position.to_point(&buffer),
1189                                height
1190                            );
1191                            BlockProperties {
1192                                position,
1193                                height,
1194                                disposition,
1195                                render: Arc::new(|_| Empty::new().boxed()),
1196                            }
1197                        })
1198                        .collect::<Vec<_>>();
1199
1200                    let (folds_snapshot, fold_edits) =
1201                        fold_map.read(buffer_snapshot.clone(), vec![]);
1202                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1203                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1204                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1205                    });
1206                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1207                    let block_ids = block_map.insert(block_properties.clone());
1208                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1209                        expected_blocks.push((block_id, props));
1210                    }
1211                }
1212                40..=59 if !expected_blocks.is_empty() => {
1213                    let block_count = rng.gen_range(1..=4.min(expected_blocks.len()));
1214                    let block_ids_to_remove = (0..block_count)
1215                        .map(|_| {
1216                            expected_blocks
1217                                .remove(rng.gen_range(0..expected_blocks.len()))
1218                                .0
1219                        })
1220                        .collect();
1221
1222                    let (folds_snapshot, fold_edits) =
1223                        fold_map.read(buffer_snapshot.clone(), vec![]);
1224                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1225                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1226                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1227                    });
1228                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1229                    block_map.remove(block_ids_to_remove);
1230                }
1231                _ => {
1232                    buffer.update(cx, |buffer, cx| {
1233                        let edit_count = rng.gen_range(1..=5);
1234                        let subscription = buffer.subscribe();
1235                        buffer.randomly_edit(&mut rng, edit_count, cx);
1236                        buffer_snapshot = buffer.snapshot(cx);
1237                        buffer_edits.extend(subscription.consume());
1238                        log::info!("buffer text: {:?}", buffer_snapshot.text());
1239                    });
1240                }
1241            }
1242
1243            let (folds_snapshot, fold_edits) = fold_map.read(buffer_snapshot.clone(), buffer_edits);
1244            let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1245            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1246                wrap_map.sync(tabs_snapshot, tab_edits, cx)
1247            });
1248            let blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits);
1249            assert_eq!(
1250                blocks_snapshot.transforms.summary().input_rows,
1251                wraps_snapshot.max_point().row() + 1
1252            );
1253            log::info!("blocks text: {:?}", blocks_snapshot.text());
1254
1255            let mut sorted_blocks = expected_blocks
1256                .iter()
1257                .cloned()
1258                .map(|(id, block)| {
1259                    let mut position = block.position.to_point(&buffer_snapshot);
1260                    let column = wraps_snapshot.from_point(position, Bias::Left).column();
1261                    match block.disposition {
1262                        BlockDisposition::Above => {
1263                            position.column = 0;
1264                        }
1265                        BlockDisposition::Below => {
1266                            position.column = buffer_snapshot.line_len(position.row);
1267                        }
1268                    };
1269                    let row = wraps_snapshot.from_point(position, Bias::Left).row();
1270                    (
1271                        id,
1272                        BlockProperties {
1273                            position: BlockPoint::new(row, column),
1274                            height: block.height,
1275                            disposition: block.disposition,
1276                            render: block.render.clone(),
1277                        },
1278                    )
1279                })
1280                .collect::<Vec<_>>();
1281            sorted_blocks.sort_unstable_by_key(|(id, block)| {
1282                (block.position.row, block.disposition, Reverse(*id))
1283            });
1284            let mut sorted_blocks_iter = sorted_blocks.iter().peekable();
1285
1286            let input_buffer_rows = buffer_snapshot.buffer_rows(0).collect::<Vec<_>>();
1287            let mut expected_buffer_rows = Vec::new();
1288            let mut expected_text = String::new();
1289            let mut expected_block_positions = Vec::new();
1290            let input_text = wraps_snapshot.text();
1291            for (row, input_line) in input_text.split('\n').enumerate() {
1292                let row = row as u32;
1293                if row > 0 {
1294                    expected_text.push('\n');
1295                }
1296
1297                let buffer_row = input_buffer_rows[wraps_snapshot
1298                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1299                    .row as usize];
1300
1301                while let Some((block_id, block)) = sorted_blocks_iter.peek() {
1302                    if block.position.row == row && block.disposition == BlockDisposition::Above {
1303                        expected_block_positions
1304                            .push((expected_text.matches('\n').count() as u32, *block_id));
1305                        let text = "\n".repeat(block.height as usize);
1306                        expected_text.push_str(&text);
1307                        for _ in 0..block.height {
1308                            expected_buffer_rows.push(None);
1309                        }
1310                        sorted_blocks_iter.next();
1311                    } else {
1312                        break;
1313                    }
1314                }
1315
1316                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1317                expected_buffer_rows.push(if soft_wrapped { None } else { buffer_row });
1318                expected_text.push_str(input_line);
1319
1320                while let Some((block_id, block)) = sorted_blocks_iter.peek() {
1321                    if block.position.row == row && block.disposition == BlockDisposition::Below {
1322                        expected_block_positions
1323                            .push((expected_text.matches('\n').count() as u32 + 1, *block_id));
1324                        let text = "\n".repeat(block.height as usize);
1325                        expected_text.push_str(&text);
1326                        for _ in 0..block.height {
1327                            expected_buffer_rows.push(None);
1328                        }
1329                        sorted_blocks_iter.next();
1330                    } else {
1331                        break;
1332                    }
1333                }
1334            }
1335
1336            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1337            let expected_row_count = expected_lines.len();
1338            for start_row in 0..expected_row_count {
1339                let expected_text = expected_lines[start_row..].join("\n");
1340                let actual_text = blocks_snapshot
1341                    .chunks(start_row as u32..expected_row_count as u32, None)
1342                    .map(|chunk| chunk.text)
1343                    .collect::<String>();
1344                assert_eq!(
1345                    actual_text, expected_text,
1346                    "incorrect text starting from row {}",
1347                    start_row
1348                );
1349                assert_eq!(
1350                    blocks_snapshot
1351                        .buffer_rows(start_row as u32)
1352                        .collect::<Vec<_>>(),
1353                    &expected_buffer_rows[start_row..]
1354                );
1355            }
1356
1357            assert_eq!(
1358                blocks_snapshot
1359                    .blocks_in_range(0..(expected_row_count as u32))
1360                    .map(|(row, block)| (row, block.id))
1361                    .collect::<Vec<_>>(),
1362                expected_block_positions
1363            );
1364
1365            let mut expected_longest_rows = Vec::new();
1366            let mut longest_line_len = -1_isize;
1367            for (row, line) in expected_lines.iter().enumerate() {
1368                let row = row as u32;
1369
1370                assert_eq!(
1371                    blocks_snapshot.line_len(row),
1372                    line.len() as u32,
1373                    "invalid line len for row {}",
1374                    row
1375                );
1376
1377                let line_char_count = line.chars().count() as isize;
1378                match line_char_count.cmp(&longest_line_len) {
1379                    Ordering::Less => {}
1380                    Ordering::Equal => expected_longest_rows.push(row),
1381                    Ordering::Greater => {
1382                        longest_line_len = line_char_count;
1383                        expected_longest_rows.clear();
1384                        expected_longest_rows.push(row);
1385                    }
1386                }
1387            }
1388
1389            let longest_row = blocks_snapshot.longest_row();
1390            assert!(
1391                expected_longest_rows.contains(&longest_row),
1392                "incorrect longest row {}. expected {:?} with length {}",
1393                longest_row,
1394                expected_longest_rows,
1395                longest_line_len,
1396            );
1397
1398            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1399                let wrap_point = WrapPoint::new(row, 0);
1400                let block_point = blocks_snapshot.to_block_point(wrap_point);
1401                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1402            }
1403
1404            let mut block_point = BlockPoint::new(0, 0);
1405            for c in expected_text.chars() {
1406                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1407                let left_buffer_point = blocks_snapshot.to_point(left_point, Bias::Left);
1408                assert_eq!(
1409                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1410                    left_point
1411                );
1412                assert_eq!(
1413                    left_buffer_point,
1414                    buffer_snapshot.clip_point(left_buffer_point, Bias::Right),
1415                    "{:?} is not valid in buffer coordinates",
1416                    left_point
1417                );
1418
1419                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1420                let right_buffer_point = blocks_snapshot.to_point(right_point, Bias::Right);
1421                assert_eq!(
1422                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1423                    right_point
1424                );
1425                assert_eq!(
1426                    right_buffer_point,
1427                    buffer_snapshot.clip_point(right_buffer_point, Bias::Left),
1428                    "{:?} is not valid in buffer coordinates",
1429                    right_point
1430                );
1431
1432                if c == '\n' {
1433                    block_point.0 += Point::new(1, 0);
1434                } else {
1435                    block_point.column += c.len_utf8() as u32;
1436                }
1437            }
1438        }
1439    }
1440
1441    impl BlockSnapshot {
1442        fn to_point(&self, point: BlockPoint, bias: Bias) -> Point {
1443            self.wrap_snapshot.to_point(self.to_wrap_point(point), bias)
1444        }
1445    }
1446}