block_map.rs

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