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::{BufferSnapshot, Chunk};
   6use parking_lot::Mutex;
   7use std::{
   8    cmp::{self, Ordering},
   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};
  18
  19const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  20
  21pub struct BlockMap {
  22    next_block_id: AtomicUsize,
  23    wrap_snapshot: Mutex<WrapSnapshot>,
  24    blocks: Vec<Arc<Block>>,
  25    transforms: Mutex<SumTree<Transform>>,
  26    excerpt_header_height: u8,
  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 scroll_x: f32,
  73    pub gutter_width: f32,
  74    pub gutter_padding: f32,
  75    pub em_width: f32,
  76    pub line_height: f32,
  77}
  78
  79#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
  80pub enum BlockDisposition {
  81    Above,
  82    Below,
  83}
  84
  85#[derive(Clone, Debug)]
  86struct Transform {
  87    summary: TransformSummary,
  88    block: Option<TransformBlock>,
  89}
  90
  91#[derive(Clone)]
  92pub enum TransformBlock {
  93    Custom {
  94        block: Arc<Block>,
  95        column: u32,
  96    },
  97    ExcerptHeader {
  98        buffer: BufferSnapshot,
  99        range: Range<text::Anchor>,
 100        height: u8,
 101    },
 102}
 103
 104impl TransformBlock {
 105    fn disposition(&self) -> BlockDisposition {
 106        match self {
 107            TransformBlock::Custom { block, .. } => block.disposition,
 108            TransformBlock::ExcerptHeader { .. } => BlockDisposition::Above,
 109        }
 110    }
 111
 112    fn height(&self) -> u8 {
 113        match self {
 114            TransformBlock::Custom { block, .. } => block.height,
 115            TransformBlock::ExcerptHeader { height, .. } => *height,
 116        }
 117    }
 118}
 119
 120impl Debug for TransformBlock {
 121    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 122        match self {
 123            Self::Custom { block, column } => f
 124                .debug_struct("Custom")
 125                .field("block", block)
 126                .field("column", column)
 127                .finish(),
 128            Self::ExcerptHeader { buffer, .. } => f
 129                .debug_struct("ExcerptHeader")
 130                .field("path", &buffer.path())
 131                .finish(),
 132        }
 133    }
 134}
 135
 136#[derive(Clone, Debug, Default)]
 137struct TransformSummary {
 138    input_rows: u32,
 139    output_rows: u32,
 140}
 141
 142pub struct BlockChunks<'a> {
 143    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 144    input_chunks: wrap_map::WrapChunks<'a>,
 145    input_chunk: Chunk<'a>,
 146    output_row: u32,
 147    max_output_row: u32,
 148}
 149
 150pub struct BlockBufferRows<'a> {
 151    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 152    input_buffer_rows: wrap_map::WrapBufferRows<'a>,
 153    output_row: u32,
 154    started: bool,
 155}
 156
 157impl BlockMap {
 158    pub fn new(wrap_snapshot: WrapSnapshot, excerpt_header_height: u8) -> Self {
 159        Self {
 160            next_block_id: AtomicUsize::new(0),
 161            blocks: Vec::new(),
 162            transforms: Mutex::new(SumTree::from_item(
 163                Transform::isomorphic(wrap_snapshot.text_summary().lines.row + 1),
 164                &(),
 165            )),
 166            wrap_snapshot: Mutex::new(wrap_snapshot),
 167            excerpt_header_height,
 168        }
 169    }
 170
 171    pub fn read(&self, wrap_snapshot: WrapSnapshot, edits: Vec<WrapEdit>) -> BlockSnapshot {
 172        self.sync(&wrap_snapshot, edits);
 173        *self.wrap_snapshot.lock() = wrap_snapshot.clone();
 174        BlockSnapshot {
 175            wrap_snapshot,
 176            transforms: self.transforms.lock().clone(),
 177        }
 178    }
 179
 180    pub fn write(&mut self, wrap_snapshot: WrapSnapshot, edits: Vec<WrapEdit>) -> BlockMapWriter {
 181        self.sync(&wrap_snapshot, edits);
 182        *self.wrap_snapshot.lock() = wrap_snapshot;
 183        BlockMapWriter(self)
 184    }
 185
 186    fn sync(&self, wrap_snapshot: &WrapSnapshot, edits: Vec<WrapEdit>) {
 187        if edits.is_empty() {
 188            return;
 189        }
 190
 191        let buffer = wrap_snapshot.buffer_snapshot();
 192        let mut transforms = self.transforms.lock();
 193        let mut new_transforms = SumTree::new();
 194        let old_row_count = transforms.summary().input_rows;
 195        let new_row_count = wrap_snapshot.max_point().row() + 1;
 196        let mut cursor = transforms.cursor::<WrapRow>();
 197        let mut last_block_ix = 0;
 198        let mut blocks_in_edit = Vec::new();
 199        let mut edits = edits.into_iter().peekable();
 200
 201        while let Some(edit) = edits.next() {
 202            // Preserve any old transforms that precede this edit.
 203            let old_start = WrapRow(edit.old.start);
 204            let new_start = WrapRow(edit.new.start);
 205            new_transforms.push_tree(cursor.slice(&old_start, Bias::Left, &()), &());
 206            if let Some(transform) = cursor.item() {
 207                if transform.is_isomorphic() && old_start == cursor.end(&()) {
 208                    new_transforms.push(transform.clone(), &());
 209                    cursor.next(&());
 210                    while let Some(transform) = cursor.item() {
 211                        if transform
 212                            .block
 213                            .as_ref()
 214                            .map_or(false, |b| b.disposition().is_below())
 215                        {
 216                            new_transforms.push(transform.clone(), &());
 217                            cursor.next(&());
 218                        } else {
 219                            break;
 220                        }
 221                    }
 222                }
 223            }
 224
 225            // Preserve any portion of an old transform that precedes this edit.
 226            let extent_before_edit = old_start.0 - cursor.start().0;
 227            push_isomorphic(&mut new_transforms, extent_before_edit);
 228
 229            // Skip over any old transforms that intersect this edit.
 230            let mut old_end = WrapRow(edit.old.end);
 231            let mut new_end = WrapRow(edit.new.end);
 232            cursor.seek(&old_end, Bias::Left, &());
 233            cursor.next(&());
 234            if old_end == *cursor.start() {
 235                while let Some(transform) = cursor.item() {
 236                    if transform
 237                        .block
 238                        .as_ref()
 239                        .map_or(false, |b| b.disposition().is_below())
 240                    {
 241                        cursor.next(&());
 242                    } else {
 243                        break;
 244                    }
 245                }
 246            }
 247
 248            // Combine this edit with any subsequent edits that intersect the same transform.
 249            while let Some(next_edit) = edits.peek() {
 250                if next_edit.old.start <= cursor.start().0 {
 251                    old_end = WrapRow(next_edit.old.end);
 252                    new_end = WrapRow(next_edit.new.end);
 253                    cursor.seek(&old_end, Bias::Left, &());
 254                    cursor.next(&());
 255                    if old_end == *cursor.start() {
 256                        while let Some(transform) = cursor.item() {
 257                            if transform
 258                                .block
 259                                .as_ref()
 260                                .map_or(false, |b| b.disposition().is_below())
 261                            {
 262                                cursor.next(&());
 263                            } else {
 264                                break;
 265                            }
 266                        }
 267                    }
 268                    edits.next();
 269                } else {
 270                    break;
 271                }
 272            }
 273
 274            // Find the blocks within this edited region.
 275            let new_buffer_start =
 276                wrap_snapshot.to_point(WrapPoint::new(new_start.0, 0), Bias::Left);
 277            let start_anchor = buffer.anchor_before(new_buffer_start);
 278            let start_block_ix = match self.blocks[last_block_ix..].binary_search_by(|probe| {
 279                probe
 280                    .position
 281                    .cmp(&start_anchor, &buffer)
 282                    .unwrap()
 283                    .then(Ordering::Greater)
 284            }) {
 285                Ok(ix) | Err(ix) => last_block_ix + ix,
 286            };
 287
 288            let end_anchor;
 289            let end_block_ix = if new_end.0 > wrap_snapshot.max_point().row() {
 290                end_anchor = Anchor::max();
 291                self.blocks.len()
 292            } else {
 293                let new_buffer_end =
 294                    wrap_snapshot.to_point(WrapPoint::new(new_end.0, 0), Bias::Left);
 295                end_anchor = buffer.anchor_before(new_buffer_end);
 296                match self.blocks[start_block_ix..].binary_search_by(|probe| {
 297                    probe
 298                        .position
 299                        .cmp(&end_anchor, &buffer)
 300                        .unwrap()
 301                        .then(Ordering::Greater)
 302                }) {
 303                    Ok(ix) | Err(ix) => start_block_ix + ix,
 304                }
 305            };
 306            last_block_ix = end_block_ix;
 307
 308            debug_assert!(blocks_in_edit.is_empty());
 309            blocks_in_edit.extend(
 310                self.blocks[start_block_ix..end_block_ix]
 311                    .iter()
 312                    .map(|block| {
 313                        let mut position = block.position.to_point(&buffer);
 314                        let column = wrap_snapshot.from_point(position, Bias::Left).column();
 315                        match block.disposition {
 316                            BlockDisposition::Above => position.column = 0,
 317                            BlockDisposition::Below => {
 318                                position.column = buffer.line_len(position.row)
 319                            }
 320                        }
 321                        let position = wrap_snapshot.from_point(position, Bias::Left);
 322                        (
 323                            position.row(),
 324                            TransformBlock::Custom {
 325                                block: block.clone(),
 326                                column,
 327                            },
 328                        )
 329                    }),
 330            );
 331            blocks_in_edit.extend(
 332                buffer
 333                    .excerpt_boundaries_in_range(start_anchor..end_anchor)
 334                    .map(|excerpt_boundary| {
 335                        (
 336                            excerpt_boundary.row,
 337                            TransformBlock::ExcerptHeader {
 338                                buffer: excerpt_boundary.buffer,
 339                                range: excerpt_boundary.range,
 340                                height: self.excerpt_header_height,
 341                            },
 342                        )
 343                    }),
 344            );
 345
 346            // When multiple blocks are on the same row, newer blocks appear above older
 347            // blocks. This is arbitrary, but we currently rely on it in ProjectDiagnosticsEditor.
 348            blocks_in_edit.sort_unstable_by(|(row_a, block_a), (row_b, block_b)| {
 349                row_a.cmp(&row_b).then_with(|| match (block_a, block_b) {
 350                    (
 351                        TransformBlock::ExcerptHeader { .. },
 352                        TransformBlock::ExcerptHeader { .. },
 353                    ) => Ordering::Equal,
 354                    (TransformBlock::ExcerptHeader { .. }, _) => Ordering::Less,
 355                    (_, TransformBlock::ExcerptHeader { .. }) => Ordering::Greater,
 356                    (
 357                        TransformBlock::Custom { block: block_a, .. },
 358                        TransformBlock::Custom { block: block_b, .. },
 359                    ) => block_a
 360                        .disposition
 361                        .cmp(&block_b.disposition)
 362                        .then_with(|| block_a.id.cmp(&block_b.id).reverse()),
 363                })
 364            });
 365
 366            // For each of these blocks, insert a new isomorphic transform preceding the block,
 367            // and then insert the block itself.
 368            for (block_row, block) in blocks_in_edit.drain(..) {
 369                let insertion_row = match block.disposition() {
 370                    BlockDisposition::Above => block_row,
 371                    BlockDisposition::Below => block_row + 1,
 372                };
 373                let extent_before_block = insertion_row - new_transforms.summary().input_rows;
 374                push_isomorphic(&mut new_transforms, extent_before_block);
 375                new_transforms.push(Transform::block(block), &());
 376            }
 377
 378            old_end = WrapRow(old_end.0.min(old_row_count));
 379            new_end = WrapRow(new_end.0.min(new_row_count));
 380
 381            // Insert an isomorphic transform after the final block.
 382            let extent_after_last_block = new_end.0 - new_transforms.summary().input_rows;
 383            push_isomorphic(&mut new_transforms, extent_after_last_block);
 384
 385            // Preserve any portion of the old transform after this edit.
 386            let extent_after_edit = cursor.start().0 - old_end.0;
 387            push_isomorphic(&mut new_transforms, extent_after_edit);
 388        }
 389
 390        new_transforms.push_tree(cursor.suffix(&()), &());
 391        debug_assert_eq!(
 392            new_transforms.summary().input_rows,
 393            wrap_snapshot.max_point().row() + 1
 394        );
 395
 396        drop(cursor);
 397        *transforms = new_transforms;
 398    }
 399
 400    pub fn replace(&mut self, mut renderers: HashMap<BlockId, RenderBlock>) {
 401        for block in &self.blocks {
 402            if let Some(render) = renderers.remove(&block.id) {
 403                *block.render.lock() = render;
 404            }
 405        }
 406    }
 407}
 408
 409fn push_isomorphic(tree: &mut SumTree<Transform>, rows: u32) {
 410    if rows == 0 {
 411        return;
 412    }
 413
 414    let mut extent = Some(rows);
 415    tree.update_last(
 416        |last_transform| {
 417            if last_transform.is_isomorphic() {
 418                let extent = extent.take().unwrap();
 419                last_transform.summary.input_rows += extent;
 420                last_transform.summary.output_rows += extent;
 421            }
 422        },
 423        &(),
 424    );
 425    if let Some(extent) = extent {
 426        tree.push(Transform::isomorphic(extent), &());
 427    }
 428}
 429
 430impl BlockPoint {
 431    pub fn new(row: u32, column: u32) -> Self {
 432        Self(Point::new(row, column))
 433    }
 434}
 435
 436impl Deref for BlockPoint {
 437    type Target = Point;
 438
 439    fn deref(&self) -> &Self::Target {
 440        &self.0
 441    }
 442}
 443
 444impl std::ops::DerefMut for BlockPoint {
 445    fn deref_mut(&mut self) -> &mut Self::Target {
 446        &mut self.0
 447    }
 448}
 449
 450impl<'a> BlockMapWriter<'a> {
 451    pub fn insert(
 452        &mut self,
 453        blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
 454    ) -> Vec<BlockId> {
 455        let mut ids = Vec::new();
 456        let mut edits = Vec::<Edit<u32>>::new();
 457        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 458        let buffer = wrap_snapshot.buffer_snapshot();
 459
 460        for block in blocks {
 461            let id = BlockId(self.0.next_block_id.fetch_add(1, SeqCst));
 462            ids.push(id);
 463
 464            let position = block.position;
 465            let point = position.to_point(&buffer);
 466            let wrap_row = wrap_snapshot
 467                .from_point(Point::new(point.row, 0), Bias::Left)
 468                .row();
 469            let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 470            let end_row = wrap_snapshot
 471                .next_row_boundary(WrapPoint::new(wrap_row, 0))
 472                .unwrap_or(wrap_snapshot.max_point().row() + 1);
 473
 474            let block_ix = match self
 475                .0
 476                .blocks
 477                .binary_search_by(|probe| probe.position.cmp(&position, &buffer).unwrap())
 478            {
 479                Ok(ix) | Err(ix) => ix,
 480            };
 481            self.0.blocks.insert(
 482                block_ix,
 483                Arc::new(Block {
 484                    id,
 485                    position,
 486                    height: block.height,
 487                    render: Mutex::new(block.render),
 488                    disposition: block.disposition,
 489                }),
 490            );
 491
 492            if let Err(edit_ix) = edits.binary_search_by_key(&start_row, |edit| edit.old.start) {
 493                edits.insert(
 494                    edit_ix,
 495                    Edit {
 496                        old: start_row..end_row,
 497                        new: start_row..end_row,
 498                    },
 499                );
 500            }
 501        }
 502
 503        self.0.sync(wrap_snapshot, edits);
 504        ids
 505    }
 506
 507    pub fn remove(&mut self, block_ids: HashSet<BlockId>) {
 508        let wrap_snapshot = &*self.0.wrap_snapshot.lock();
 509        let buffer = wrap_snapshot.buffer_snapshot();
 510        let mut edits = Vec::new();
 511        let mut last_block_buffer_row = None;
 512        self.0.blocks.retain(|block| {
 513            if block_ids.contains(&block.id) {
 514                let buffer_row = block.position.to_point(&buffer).row;
 515                if last_block_buffer_row != Some(buffer_row) {
 516                    last_block_buffer_row = Some(buffer_row);
 517                    let wrap_row = wrap_snapshot
 518                        .from_point(Point::new(buffer_row, 0), Bias::Left)
 519                        .row();
 520                    let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 521                    let end_row = wrap_snapshot
 522                        .next_row_boundary(WrapPoint::new(wrap_row, 0))
 523                        .unwrap_or(wrap_snapshot.max_point().row() + 1);
 524                    edits.push(Edit {
 525                        old: start_row..end_row,
 526                        new: start_row..end_row,
 527                    })
 528                }
 529                false
 530            } else {
 531                true
 532            }
 533        });
 534        self.0.sync(wrap_snapshot, edits);
 535    }
 536}
 537
 538impl BlockSnapshot {
 539    #[cfg(test)]
 540    pub fn text(&self) -> String {
 541        self.chunks(0..self.transforms.summary().output_rows, false)
 542            .map(|chunk| chunk.text)
 543            .collect()
 544    }
 545
 546    pub fn chunks<'a>(&'a self, rows: Range<u32>, language_aware: bool) -> BlockChunks<'a> {
 547        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 548        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 549        let input_end = {
 550            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 551            let overshoot = if cursor
 552                .item()
 553                .map_or(false, |transform| transform.is_isomorphic())
 554            {
 555                rows.end - cursor.start().0 .0
 556            } else {
 557                0
 558            };
 559            cursor.start().1 .0 + overshoot
 560        };
 561        let input_start = {
 562            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 563            let overshoot = if cursor
 564                .item()
 565                .map_or(false, |transform| transform.is_isomorphic())
 566            {
 567                rows.start - cursor.start().0 .0
 568            } else {
 569                0
 570            };
 571            cursor.start().1 .0 + overshoot
 572        };
 573        BlockChunks {
 574            input_chunks: self
 575                .wrap_snapshot
 576                .chunks(input_start..input_end, language_aware),
 577            input_chunk: Default::default(),
 578            transforms: cursor,
 579            output_row: rows.start,
 580            max_output_row,
 581        }
 582    }
 583
 584    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> BlockBufferRows<'a> {
 585        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 586        cursor.seek(&BlockRow(start_row), Bias::Right, &());
 587        let (output_start, input_start) = cursor.start();
 588        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 589            start_row - output_start.0
 590        } else {
 591            0
 592        };
 593        let input_start_row = input_start.0 + overshoot;
 594        BlockBufferRows {
 595            transforms: cursor,
 596            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 597            output_row: start_row,
 598            started: false,
 599        }
 600    }
 601
 602    pub fn blocks_in_range<'a>(
 603        &'a self,
 604        rows: Range<u32>,
 605    ) -> impl Iterator<Item = (u32, &'a TransformBlock)> {
 606        let mut cursor = self.transforms.cursor::<BlockRow>();
 607        cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 608        std::iter::from_fn(move || {
 609            while let Some(transform) = cursor.item() {
 610                let start_row = cursor.start().0;
 611                if start_row >= rows.end {
 612                    break;
 613                }
 614                if let Some(block) = &transform.block {
 615                    cursor.next(&());
 616                    return Some((start_row, block));
 617                } else {
 618                    cursor.next(&());
 619                }
 620            }
 621            None
 622        })
 623    }
 624
 625    pub fn max_point(&self) -> BlockPoint {
 626        let row = self.transforms.summary().output_rows - 1;
 627        BlockPoint::new(row, self.line_len(row))
 628    }
 629
 630    pub fn longest_row(&self) -> u32 {
 631        let input_row = self.wrap_snapshot.longest_row();
 632        self.to_block_point(WrapPoint::new(input_row, 0)).row
 633    }
 634
 635    pub fn line_len(&self, row: u32) -> u32 {
 636        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 637        cursor.seek(&BlockRow(row), Bias::Right, &());
 638        if let Some(transform) = cursor.item() {
 639            let (output_start, input_start) = cursor.start();
 640            let overshoot = row - output_start.0;
 641            if transform.block.is_some() {
 642                0
 643            } else {
 644                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 645            }
 646        } else {
 647            panic!("row out of range");
 648        }
 649    }
 650
 651    pub fn is_block_line(&self, row: u32) -> bool {
 652        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 653        cursor.seek(&BlockRow(row), Bias::Right, &());
 654        cursor.item().map_or(false, |t| t.block.is_some())
 655    }
 656
 657    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 658        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 659        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 660
 661        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 662        let mut search_left =
 663            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 664        let mut reversed = false;
 665
 666        loop {
 667            if let Some(transform) = cursor.item() {
 668                if transform.is_isomorphic() {
 669                    let (output_start_row, input_start_row) = cursor.start();
 670                    let (output_end_row, input_end_row) = cursor.end(&());
 671                    let output_start = Point::new(output_start_row.0, 0);
 672                    let input_start = Point::new(input_start_row.0, 0);
 673                    let input_end = Point::new(input_end_row.0, 0);
 674                    let input_point = if point.row >= output_end_row.0 {
 675                        let line_len = self.wrap_snapshot.line_len(input_end_row.0 - 1);
 676                        self.wrap_snapshot
 677                            .clip_point(WrapPoint::new(input_end_row.0 - 1, line_len), bias)
 678                    } else {
 679                        let output_overshoot = point.0.saturating_sub(output_start);
 680                        self.wrap_snapshot
 681                            .clip_point(WrapPoint(input_start + output_overshoot), bias)
 682                    };
 683
 684                    if (input_start..input_end).contains(&input_point.0) {
 685                        let input_overshoot = input_point.0.saturating_sub(input_start);
 686                        return BlockPoint(output_start + input_overshoot);
 687                    }
 688                }
 689
 690                if search_left {
 691                    cursor.prev(&());
 692                } else {
 693                    cursor.next(&());
 694                }
 695            } else if reversed {
 696                return self.max_point();
 697            } else {
 698                reversed = true;
 699                search_left = !search_left;
 700                cursor.seek(&BlockRow(point.row), Bias::Right, &());
 701            }
 702        }
 703    }
 704
 705    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 706        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 707        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 708        if let Some(transform) = cursor.item() {
 709            debug_assert!(transform.is_isomorphic());
 710        } else {
 711            return self.max_point();
 712        }
 713
 714        let (input_start_row, output_start_row) = cursor.start();
 715        let input_start = Point::new(input_start_row.0, 0);
 716        let output_start = Point::new(output_start_row.0, 0);
 717        let input_overshoot = wrap_point.0 - input_start;
 718        BlockPoint(output_start + input_overshoot)
 719    }
 720
 721    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 722        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 723        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 724        if let Some(transform) = cursor.item() {
 725            match transform.block.as_ref().map(|b| b.disposition()) {
 726                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 727                Some(BlockDisposition::Below) => {
 728                    let wrap_row = cursor.start().1 .0 - 1;
 729                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
 730                }
 731                None => {
 732                    let overshoot = block_point.row - cursor.start().0 .0;
 733                    let wrap_row = cursor.start().1 .0 + overshoot;
 734                    WrapPoint::new(wrap_row, block_point.column)
 735                }
 736            }
 737        } else {
 738            self.wrap_snapshot.max_point()
 739        }
 740    }
 741}
 742
 743impl Transform {
 744    fn isomorphic(rows: u32) -> Self {
 745        Self {
 746            summary: TransformSummary {
 747                input_rows: rows,
 748                output_rows: rows,
 749            },
 750            block: None,
 751        }
 752    }
 753
 754    fn block(block: TransformBlock) -> Self {
 755        Self {
 756            summary: TransformSummary {
 757                input_rows: 0,
 758                output_rows: block.height() as u32,
 759            },
 760            block: Some(block),
 761        }
 762    }
 763
 764    fn is_isomorphic(&self) -> bool {
 765        self.block.is_none()
 766    }
 767}
 768
 769impl<'a> Iterator for BlockChunks<'a> {
 770    type Item = Chunk<'a>;
 771
 772    fn next(&mut self) -> Option<Self::Item> {
 773        if self.output_row >= self.max_output_row {
 774            return None;
 775        }
 776
 777        let transform = self.transforms.item()?;
 778        if transform.block.is_some() {
 779            let block_start = self.transforms.start().0 .0;
 780            let mut block_end = self.transforms.end(&()).0 .0;
 781            self.transforms.next(&());
 782            if self.transforms.item().is_none() {
 783                block_end -= 1;
 784            }
 785
 786            let start_in_block = self.output_row - block_start;
 787            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
 788            let line_count = end_in_block - start_in_block;
 789            self.output_row += line_count;
 790
 791            return Some(Chunk {
 792                text: unsafe { std::str::from_utf8_unchecked(&NEWLINES[..line_count as usize]) },
 793                highlight_id: None,
 794                diagnostic: None,
 795            });
 796        }
 797
 798        if self.input_chunk.text.is_empty() {
 799            if let Some(input_chunk) = self.input_chunks.next() {
 800                self.input_chunk = input_chunk;
 801            } else {
 802                self.output_row += 1;
 803                if self.output_row < self.max_output_row {
 804                    self.transforms.next(&());
 805                    return Some(Chunk {
 806                        text: "\n",
 807                        ..Default::default()
 808                    });
 809                } else {
 810                    return None;
 811                }
 812            }
 813        }
 814
 815        let transform_end = self.transforms.end(&()).0 .0;
 816        let (prefix_rows, prefix_bytes) =
 817            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
 818        self.output_row += prefix_rows;
 819        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
 820        self.input_chunk.text = suffix;
 821        if self.output_row == transform_end {
 822            self.transforms.next(&());
 823        }
 824
 825        Some(Chunk {
 826            text: prefix,
 827            ..self.input_chunk
 828        })
 829    }
 830}
 831
 832impl<'a> Iterator for BlockBufferRows<'a> {
 833    type Item = Option<u32>;
 834
 835    fn next(&mut self) -> Option<Self::Item> {
 836        if self.started {
 837            self.output_row += 1;
 838        } else {
 839            self.started = true;
 840        }
 841
 842        if self.output_row >= self.transforms.end(&()).0 .0 {
 843            self.transforms.next(&());
 844        }
 845
 846        let transform = self.transforms.item()?;
 847        if transform.block.is_some() {
 848            Some(None)
 849        } else {
 850            Some(self.input_buffer_rows.next().unwrap())
 851        }
 852    }
 853}
 854
 855impl sum_tree::Item for Transform {
 856    type Summary = TransformSummary;
 857
 858    fn summary(&self) -> Self::Summary {
 859        self.summary.clone()
 860    }
 861}
 862
 863impl sum_tree::Summary for TransformSummary {
 864    type Context = ();
 865
 866    fn add_summary(&mut self, summary: &Self, _: &()) {
 867        self.input_rows += summary.input_rows;
 868        self.output_rows += summary.output_rows;
 869    }
 870}
 871
 872impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
 873    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 874        self.0 += summary.input_rows;
 875    }
 876}
 877
 878impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
 879    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 880        self.0 += summary.output_rows;
 881    }
 882}
 883
 884impl BlockDisposition {
 885    fn is_below(&self) -> bool {
 886        matches!(self, BlockDisposition::Below)
 887    }
 888}
 889
 890impl<'a> Deref for BlockContext<'a> {
 891    type Target = AppContext;
 892
 893    fn deref(&self) -> &Self::Target {
 894        &self.cx
 895    }
 896}
 897
 898impl Block {
 899    pub fn render(&self, cx: &BlockContext) -> ElementBox {
 900        self.render.lock()(cx)
 901    }
 902}
 903
 904impl Debug for Block {
 905    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 906        f.debug_struct("Block")
 907            .field("id", &self.id)
 908            .field("position", &self.position)
 909            .field("disposition", &self.disposition)
 910            .finish()
 911    }
 912}
 913
 914// Count the number of bytes prior to a target point. If the string doesn't contain the target
 915// point, return its total extent. Otherwise return the target point itself.
 916fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 917    let mut row = 0;
 918    let mut offset = 0;
 919    for (ix, line) in s.split('\n').enumerate() {
 920        if ix > 0 {
 921            row += 1;
 922            offset += 1;
 923        }
 924        if row >= target {
 925            break;
 926        }
 927        offset += line.len() as usize;
 928    }
 929    (row, offset)
 930}
 931
 932#[cfg(test)]
 933mod tests {
 934    use super::*;
 935    use crate::display_map::{fold_map::FoldMap, tab_map::TabMap, wrap_map::WrapMap};
 936    use crate::multi_buffer::MultiBuffer;
 937    use gpui::{elements::Empty, Element};
 938    use rand::prelude::*;
 939    use std::cmp::Reverse;
 940    use std::env;
 941    use text::RandomCharIter;
 942
 943    #[gpui::test]
 944    fn test_offset_for_row() {
 945        assert_eq!(offset_for_row("", 0), (0, 0));
 946        assert_eq!(offset_for_row("", 1), (0, 0));
 947        assert_eq!(offset_for_row("abcd", 0), (0, 0));
 948        assert_eq!(offset_for_row("abcd", 1), (0, 4));
 949        assert_eq!(offset_for_row("\n", 0), (0, 0));
 950        assert_eq!(offset_for_row("\n", 1), (1, 1));
 951        assert_eq!(offset_for_row("abc\ndef\nghi", 0), (0, 0));
 952        assert_eq!(offset_for_row("abc\ndef\nghi", 1), (1, 4));
 953        assert_eq!(offset_for_row("abc\ndef\nghi", 2), (2, 8));
 954        assert_eq!(offset_for_row("abc\ndef\nghi", 3), (2, 11));
 955    }
 956
 957    #[gpui::test]
 958    fn test_basic_blocks(cx: &mut gpui::MutableAppContext) {
 959        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
 960        let font_id = cx
 961            .font_cache()
 962            .select_font(family_id, &Default::default())
 963            .unwrap();
 964
 965        let text = "aaa\nbbb\nccc\nddd";
 966
 967        let buffer = MultiBuffer::build_simple(text, cx);
 968        let buffer_snapshot = buffer.read(cx).snapshot(cx);
 969        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
 970        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
 971        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
 972        let (wrap_map, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, None, cx);
 973        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1);
 974
 975        let mut writer = block_map.write(wraps_snapshot.clone(), vec![]);
 976        writer.insert(vec![
 977            BlockProperties {
 978                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
 979                height: 1,
 980                disposition: BlockDisposition::Above,
 981                render: Arc::new(|_| Empty::new().named("block 1")),
 982            },
 983            BlockProperties {
 984                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
 985                height: 2,
 986                disposition: BlockDisposition::Above,
 987                render: Arc::new(|_| Empty::new().named("block 2")),
 988            },
 989            BlockProperties {
 990                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
 991                height: 3,
 992                disposition: BlockDisposition::Below,
 993                render: Arc::new(|_| Empty::new().named("block 3")),
 994            },
 995        ]);
 996
 997        let snapshot = block_map.read(wraps_snapshot, vec![]);
 998        assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
 999
1000        let blocks = snapshot
1001            .blocks_in_range(0..8)
1002            .map(|(start_row, block)| {
1003                let (block, column) = block.as_custom().unwrap();
1004                (
1005                    start_row..start_row + block.height as u32,
1006                    column,
1007                    block
1008                        .render(&BlockContext {
1009                            cx,
1010                            anchor_x: 0.,
1011                            gutter_padding: 0.,
1012                            scroll_x: 0.,
1013                            gutter_width: 0.,
1014                            line_height: 0.,
1015                            em_width: 0.,
1016                        })
1017                        .name()
1018                        .unwrap()
1019                        .to_string(),
1020                )
1021            })
1022            .collect::<Vec<_>>();
1023
1024        // When multiple blocks are on the same line, the newer blocks appear first.
1025        assert_eq!(
1026            blocks,
1027            &[
1028                (1..3, 2, "block 2".to_string()),
1029                (3..4, 0, "block 1".to_string()),
1030                (7..10, 3, "block 3".to_string()),
1031            ]
1032        );
1033
1034        assert_eq!(
1035            snapshot.to_block_point(WrapPoint::new(0, 3)),
1036            BlockPoint::new(0, 3)
1037        );
1038        assert_eq!(
1039            snapshot.to_block_point(WrapPoint::new(1, 0)),
1040            BlockPoint::new(4, 0)
1041        );
1042        assert_eq!(
1043            snapshot.to_block_point(WrapPoint::new(3, 3)),
1044            BlockPoint::new(6, 3)
1045        );
1046
1047        assert_eq!(
1048            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
1049            WrapPoint::new(0, 3)
1050        );
1051        assert_eq!(
1052            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
1053            WrapPoint::new(1, 0)
1054        );
1055        assert_eq!(
1056            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
1057            WrapPoint::new(1, 0)
1058        );
1059        assert_eq!(
1060            snapshot.to_wrap_point(BlockPoint::new(7, 0)),
1061            WrapPoint::new(3, 3)
1062        );
1063
1064        assert_eq!(
1065            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
1066            BlockPoint::new(0, 3)
1067        );
1068        assert_eq!(
1069            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
1070            BlockPoint::new(4, 0)
1071        );
1072        assert_eq!(
1073            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1074            BlockPoint::new(0, 3)
1075        );
1076        assert_eq!(
1077            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1078            BlockPoint::new(4, 0)
1079        );
1080        assert_eq!(
1081            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Left),
1082            BlockPoint::new(4, 0)
1083        );
1084        assert_eq!(
1085            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Right),
1086            BlockPoint::new(4, 0)
1087        );
1088        assert_eq!(
1089            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Left),
1090            BlockPoint::new(6, 3)
1091        );
1092        assert_eq!(
1093            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Right),
1094            BlockPoint::new(6, 3)
1095        );
1096        assert_eq!(
1097            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Left),
1098            BlockPoint::new(6, 3)
1099        );
1100        assert_eq!(
1101            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Right),
1102            BlockPoint::new(6, 3)
1103        );
1104
1105        assert_eq!(
1106            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1107            &[
1108                Some(0),
1109                None,
1110                None,
1111                None,
1112                Some(1),
1113                Some(2),
1114                Some(3),
1115                None,
1116                None,
1117                None
1118            ]
1119        );
1120
1121        // Insert a line break, separating two block decorations into separate lines.
1122        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1123            buffer.edit([Point::new(1, 1)..Point::new(1, 1)], "!!!\n", cx);
1124            buffer.snapshot(cx)
1125        });
1126
1127        let (folds_snapshot, fold_edits) =
1128            fold_map.read(buffer_snapshot, subscription.consume().into_inner());
1129        let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1130        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1131            wrap_map.sync(tabs_snapshot, tab_edits, cx)
1132        });
1133        let snapshot = block_map.read(wraps_snapshot, wrap_edits);
1134        assert_eq!(snapshot.text(), "aaa\n\nb!!!\n\n\nbb\nccc\nddd\n\n\n");
1135    }
1136
1137    #[gpui::test]
1138    fn test_blocks_on_wrapped_lines(cx: &mut gpui::MutableAppContext) {
1139        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1140        let font_id = cx
1141            .font_cache()
1142            .select_font(family_id, &Default::default())
1143            .unwrap();
1144
1145        let text = "one two three\nfour five six\nseven eight";
1146
1147        let buffer = MultiBuffer::build_simple(text, cx);
1148        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1149        let (_, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1150        let (_, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), 1);
1151        let (_, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, Some(60.), cx);
1152        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1);
1153
1154        let mut writer = block_map.write(wraps_snapshot.clone(), vec![]);
1155        writer.insert(vec![
1156            BlockProperties {
1157                position: buffer_snapshot.anchor_after(Point::new(1, 12)),
1158                disposition: BlockDisposition::Above,
1159                render: Arc::new(|_| Empty::new().named("block 1")),
1160                height: 1,
1161            },
1162            BlockProperties {
1163                position: buffer_snapshot.anchor_after(Point::new(1, 1)),
1164                disposition: BlockDisposition::Below,
1165                render: Arc::new(|_| Empty::new().named("block 2")),
1166                height: 1,
1167            },
1168        ]);
1169
1170        // Blocks with an 'above' disposition go above their corresponding buffer line.
1171        // Blocks with a 'below' disposition go below their corresponding buffer line.
1172        let snapshot = block_map.read(wraps_snapshot, vec![]);
1173        assert_eq!(
1174            snapshot.text(),
1175            "one two \nthree\n\nfour five \nsix\n\nseven \neight"
1176        );
1177    }
1178
1179    #[gpui::test(iterations = 100)]
1180    fn test_random_blocks(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1181        let operations = env::var("OPERATIONS")
1182            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1183            .unwrap_or(10);
1184
1185        let wrap_width = if rng.gen_bool(0.2) {
1186            None
1187        } else {
1188            Some(rng.gen_range(0.0..=100.0))
1189        };
1190        let tab_size = 1;
1191        let family_id = cx.font_cache().load_family(&["Helvetica"]).unwrap();
1192        let font_id = cx
1193            .font_cache()
1194            .select_font(family_id, &Default::default())
1195            .unwrap();
1196        let font_size = 14.0;
1197        let excerpt_header_height = rng.gen_range(1..=5);
1198
1199        log::info!("Wrap width: {:?}", wrap_width);
1200        log::info!("Excerpt Header Height: {:?}", excerpt_header_height);
1201
1202        let buffer = if rng.gen() {
1203            let len = rng.gen_range(0..10);
1204            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1205            log::info!("initial buffer text: {:?}", text);
1206            MultiBuffer::build_simple(&text, cx)
1207        } else {
1208            MultiBuffer::build_random(&mut rng, cx)
1209        };
1210
1211        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1212        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1213        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), tab_size);
1214        let (wrap_map, wraps_snapshot) =
1215            WrapMap::new(tabs_snapshot, font_id, font_size, wrap_width, cx);
1216        let mut block_map = BlockMap::new(wraps_snapshot, excerpt_header_height);
1217        let mut custom_blocks = Vec::new();
1218
1219        for _ in 0..operations {
1220            let mut buffer_edits = Vec::new();
1221            match rng.gen_range(0..=100) {
1222                0..=19 => {
1223                    let wrap_width = if rng.gen_bool(0.2) {
1224                        None
1225                    } else {
1226                        Some(rng.gen_range(0.0..=100.0))
1227                    };
1228                    log::info!("Setting wrap width to {:?}", wrap_width);
1229                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1230                }
1231                20..=39 => {
1232                    let block_count = rng.gen_range(1..=5);
1233                    let block_properties = (0..block_count)
1234                        .map(|_| {
1235                            let buffer = buffer.read(cx).read(cx);
1236                            let position = buffer.anchor_after(
1237                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1238                            );
1239
1240                            let disposition = if rng.gen() {
1241                                BlockDisposition::Above
1242                            } else {
1243                                BlockDisposition::Below
1244                            };
1245                            let height = rng.gen_range(1..5);
1246                            log::info!(
1247                                "inserting block {:?} {:?} with height {}",
1248                                disposition,
1249                                position.to_point(&buffer),
1250                                height
1251                            );
1252                            BlockProperties {
1253                                position,
1254                                height,
1255                                disposition,
1256                                render: Arc::new(|_| Empty::new().boxed()),
1257                            }
1258                        })
1259                        .collect::<Vec<_>>();
1260
1261                    let (folds_snapshot, fold_edits) =
1262                        fold_map.read(buffer_snapshot.clone(), vec![]);
1263                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1264                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1265                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1266                    });
1267                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1268                    let block_ids = block_map.insert(block_properties.clone());
1269                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1270                        custom_blocks.push((block_id, props));
1271                    }
1272                }
1273                40..=59 if !custom_blocks.is_empty() => {
1274                    let block_count = rng.gen_range(1..=4.min(custom_blocks.len()));
1275                    let block_ids_to_remove = (0..block_count)
1276                        .map(|_| {
1277                            custom_blocks
1278                                .remove(rng.gen_range(0..custom_blocks.len()))
1279                                .0
1280                        })
1281                        .collect();
1282
1283                    let (folds_snapshot, fold_edits) =
1284                        fold_map.read(buffer_snapshot.clone(), vec![]);
1285                    let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1286                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1287                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1288                    });
1289                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1290                    block_map.remove(block_ids_to_remove);
1291                }
1292                _ => {
1293                    buffer.update(cx, |buffer, cx| {
1294                        let edit_count = rng.gen_range(1..=5);
1295                        let subscription = buffer.subscribe();
1296                        buffer.randomly_edit(&mut rng, edit_count, cx);
1297                        buffer_snapshot = buffer.snapshot(cx);
1298                        buffer_edits.extend(subscription.consume());
1299                        log::info!("buffer text: {:?}", buffer_snapshot.text());
1300                    });
1301                }
1302            }
1303
1304            let (folds_snapshot, fold_edits) = fold_map.read(buffer_snapshot.clone(), buffer_edits);
1305            let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits);
1306            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1307                wrap_map.sync(tabs_snapshot, tab_edits, cx)
1308            });
1309            let blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits);
1310            assert_eq!(
1311                blocks_snapshot.transforms.summary().input_rows,
1312                wraps_snapshot.max_point().row() + 1
1313            );
1314            log::info!("blocks text: {:?}", blocks_snapshot.text());
1315
1316            let mut expected_blocks = Vec::new();
1317            expected_blocks.extend(custom_blocks.iter().map(|(id, block)| {
1318                let mut position = block.position.to_point(&buffer_snapshot);
1319                let column = wraps_snapshot.from_point(position, Bias::Left).column();
1320                match block.disposition {
1321                    BlockDisposition::Above => {
1322                        position.column = 0;
1323                    }
1324                    BlockDisposition::Below => {
1325                        position.column = buffer_snapshot.line_len(position.row);
1326                    }
1327                };
1328                let row = wraps_snapshot.from_point(position, Bias::Left).row();
1329                (row, block.disposition, *id, block.height)
1330            }));
1331            expected_blocks.extend(
1332                buffer_snapshot
1333                    .excerpt_boundaries_in_range(0..buffer_snapshot.len())
1334                    .map(|boundary| {
1335                        let position =
1336                            wraps_snapshot.from_point(Point::new(boundary.row, 0), Bias::Left);
1337                        (
1338                            position.row(),
1339                            BlockDisposition::Above,
1340                            BlockId(usize::MAX),
1341                            excerpt_header_height,
1342                        )
1343                    }),
1344            );
1345            expected_blocks.sort_unstable_by_key(|(row, disposition, id, _)| {
1346                (*row, *disposition, Reverse(*id))
1347            });
1348            let mut sorted_blocks_iter = expected_blocks.iter().peekable();
1349
1350            let input_buffer_rows = buffer_snapshot.buffer_rows(0).collect::<Vec<_>>();
1351            let mut expected_buffer_rows = Vec::new();
1352            let mut expected_text = String::new();
1353            let mut expected_block_positions = Vec::new();
1354            let input_text = wraps_snapshot.text();
1355            for (row, input_line) in input_text.split('\n').enumerate() {
1356                let row = row as u32;
1357                if row > 0 {
1358                    expected_text.push('\n');
1359                }
1360
1361                let buffer_row = input_buffer_rows[wraps_snapshot
1362                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1363                    .row as usize];
1364
1365                while let Some((block_row, disposition, id, height)) = sorted_blocks_iter.peek() {
1366                    if *block_row == row && *disposition == BlockDisposition::Above {
1367                        expected_block_positions
1368                            .push((expected_text.matches('\n').count() as u32, *id));
1369                        let text = "\n".repeat(*height as usize);
1370                        expected_text.push_str(&text);
1371                        for _ in 0..*height {
1372                            expected_buffer_rows.push(None);
1373                        }
1374                        sorted_blocks_iter.next();
1375                    } else {
1376                        break;
1377                    }
1378                }
1379
1380                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1381                expected_buffer_rows.push(if soft_wrapped { None } else { buffer_row });
1382                expected_text.push_str(input_line);
1383
1384                while let Some((block_row, disposition, id, height)) = sorted_blocks_iter.peek() {
1385                    if *block_row == row && *disposition == BlockDisposition::Below {
1386                        expected_block_positions
1387                            .push((expected_text.matches('\n').count() as u32 + 1, *id));
1388                        let text = "\n".repeat(*height as usize);
1389                        expected_text.push_str(&text);
1390                        for _ in 0..*height {
1391                            expected_buffer_rows.push(None);
1392                        }
1393                        sorted_blocks_iter.next();
1394                    } else {
1395                        break;
1396                    }
1397                }
1398            }
1399
1400            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1401            let expected_row_count = expected_lines.len();
1402            for start_row in 0..expected_row_count {
1403                let expected_text = expected_lines[start_row..].join("\n");
1404                let actual_text = blocks_snapshot
1405                    .chunks(start_row as u32..expected_row_count as u32, false)
1406                    .map(|chunk| chunk.text)
1407                    .collect::<String>();
1408                assert_eq!(
1409                    actual_text, expected_text,
1410                    "incorrect text starting from row {}",
1411                    start_row
1412                );
1413                assert_eq!(
1414                    blocks_snapshot
1415                        .buffer_rows(start_row as u32)
1416                        .collect::<Vec<_>>(),
1417                    &expected_buffer_rows[start_row..]
1418                );
1419            }
1420
1421            assert_eq!(
1422                blocks_snapshot
1423                    .blocks_in_range(0..(expected_row_count as u32))
1424                    .map(|(row, block)| (
1425                        row,
1426                        if let Some((block, _)) = block.as_custom() {
1427                            block.id
1428                        } else {
1429                            BlockId(usize::MAX)
1430                        }
1431                    ))
1432                    .collect::<Vec<_>>(),
1433                expected_block_positions
1434            );
1435
1436            let mut expected_longest_rows = Vec::new();
1437            let mut longest_line_len = -1_isize;
1438            for (row, line) in expected_lines.iter().enumerate() {
1439                let row = row as u32;
1440
1441                assert_eq!(
1442                    blocks_snapshot.line_len(row),
1443                    line.len() as u32,
1444                    "invalid line len for row {}",
1445                    row
1446                );
1447
1448                let line_char_count = line.chars().count() as isize;
1449                match line_char_count.cmp(&longest_line_len) {
1450                    Ordering::Less => {}
1451                    Ordering::Equal => expected_longest_rows.push(row),
1452                    Ordering::Greater => {
1453                        longest_line_len = line_char_count;
1454                        expected_longest_rows.clear();
1455                        expected_longest_rows.push(row);
1456                    }
1457                }
1458            }
1459
1460            let longest_row = blocks_snapshot.longest_row();
1461            assert!(
1462                expected_longest_rows.contains(&longest_row),
1463                "incorrect longest row {}. expected {:?} with length {}",
1464                longest_row,
1465                expected_longest_rows,
1466                longest_line_len,
1467            );
1468
1469            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1470                let wrap_point = WrapPoint::new(row, 0);
1471                let block_point = blocks_snapshot.to_block_point(wrap_point);
1472                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1473            }
1474
1475            let mut block_point = BlockPoint::new(0, 0);
1476            for c in expected_text.chars() {
1477                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1478                let left_buffer_point = blocks_snapshot.to_point(left_point, Bias::Left);
1479                assert_eq!(
1480                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1481                    left_point
1482                );
1483                assert_eq!(
1484                    left_buffer_point,
1485                    buffer_snapshot.clip_point(left_buffer_point, Bias::Right),
1486                    "{:?} is not valid in buffer coordinates",
1487                    left_point
1488                );
1489
1490                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1491                let right_buffer_point = blocks_snapshot.to_point(right_point, Bias::Right);
1492                assert_eq!(
1493                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1494                    right_point
1495                );
1496                assert_eq!(
1497                    right_buffer_point,
1498                    buffer_snapshot.clip_point(right_buffer_point, Bias::Left),
1499                    "{:?} is not valid in buffer coordinates",
1500                    right_point
1501                );
1502
1503                if c == '\n' {
1504                    block_point.0 += Point::new(1, 0);
1505                } else {
1506                    block_point.column += c.len_utf8() as u32;
1507                }
1508            }
1509        }
1510    }
1511
1512    impl TransformBlock {
1513        fn as_custom(&self) -> Option<(&Block, u32)> {
1514            match self {
1515                TransformBlock::Custom { block, column } => Some((block, *column)),
1516                TransformBlock::ExcerptHeader { .. } => None,
1517            }
1518        }
1519    }
1520
1521    impl BlockSnapshot {
1522        fn to_point(&self, point: BlockPoint, bias: Bias) -> Point {
1523            self.wrap_snapshot.to_point(self.to_wrap_point(point), bias)
1524        }
1525    }
1526}