block_map.rs

   1use super::{
   2    wrap_map::{self, WrapEdit, WrapPoint, WrapSnapshot},
   3    TextHighlights,
   4};
   5use crate::{Anchor, ExcerptId, ExcerptRange, ToPoint as _};
   6use collections::{Bound, HashMap, HashSet};
   7use gpui::{ElementBox, RenderContext};
   8use language::{BufferSnapshot, Chunk, Patch, Point};
   9use parking_lot::Mutex;
  10use std::{
  11    cell::RefCell,
  12    cmp::{self, Ordering},
  13    fmt::Debug,
  14    ops::{Deref, DerefMut, Range},
  15    sync::{
  16        atomic::{AtomicUsize, Ordering::SeqCst},
  17        Arc,
  18    },
  19};
  20use sum_tree::{Bias, SumTree};
  21use text::Edit;
  22
  23const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  24
  25pub struct BlockMap {
  26    next_block_id: AtomicUsize,
  27    wrap_snapshot: RefCell<WrapSnapshot>,
  28    blocks: Vec<Arc<Block>>,
  29    transforms: RefCell<SumTree<Transform>>,
  30    buffer_header_height: u8,
  31    excerpt_header_height: u8,
  32}
  33
  34pub struct BlockMapWriter<'a>(&'a mut BlockMap);
  35
  36pub struct BlockSnapshot {
  37    wrap_snapshot: WrapSnapshot,
  38    transforms: SumTree<Transform>,
  39}
  40
  41#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
  42pub struct BlockId(usize);
  43
  44#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  45pub struct BlockPoint(pub Point);
  46
  47#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  48struct BlockRow(u32);
  49
  50#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  51struct WrapRow(u32);
  52
  53pub type RenderBlock = Arc<dyn Fn(&mut BlockContext) -> ElementBox>;
  54
  55pub struct Block {
  56    id: BlockId,
  57    position: Anchor,
  58    height: u8,
  59    style: BlockStyle,
  60    render: Mutex<RenderBlock>,
  61    disposition: BlockDisposition,
  62}
  63
  64#[derive(Clone)]
  65pub struct BlockProperties<P>
  66where
  67    P: Clone,
  68{
  69    pub position: P,
  70    pub height: u8,
  71    pub style: BlockStyle,
  72    pub render: Arc<dyn Fn(&mut BlockContext) -> ElementBox>,
  73    pub disposition: BlockDisposition,
  74}
  75
  76#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
  77pub enum BlockStyle {
  78    Fixed,
  79    Flex,
  80    Sticky,
  81}
  82
  83pub struct BlockContext<'a, 'b> {
  84    pub cx: &'b mut RenderContext<'a, crate::Editor>,
  85    pub anchor_x: f32,
  86    pub scroll_x: f32,
  87    pub gutter_width: f32,
  88    pub gutter_padding: f32,
  89    pub em_width: f32,
  90    pub line_height: f32,
  91}
  92
  93#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
  94pub enum BlockDisposition {
  95    Above,
  96    Below,
  97}
  98
  99#[derive(Clone, Debug)]
 100struct Transform {
 101    summary: TransformSummary,
 102    block: Option<TransformBlock>,
 103}
 104
 105#[allow(clippy::large_enum_variant)]
 106#[derive(Clone)]
 107pub enum TransformBlock {
 108    Custom(Arc<Block>),
 109    ExcerptHeader {
 110        id: ExcerptId,
 111        buffer: BufferSnapshot,
 112        range: ExcerptRange<text::Anchor>,
 113        height: u8,
 114        starts_new_buffer: bool,
 115    },
 116}
 117
 118impl TransformBlock {
 119    fn disposition(&self) -> BlockDisposition {
 120        match self {
 121            TransformBlock::Custom(block) => block.disposition,
 122            TransformBlock::ExcerptHeader { .. } => BlockDisposition::Above,
 123        }
 124    }
 125
 126    pub fn height(&self) -> u8 {
 127        match self {
 128            TransformBlock::Custom(block) => block.height,
 129            TransformBlock::ExcerptHeader { height, .. } => *height,
 130        }
 131    }
 132}
 133
 134impl Debug for TransformBlock {
 135    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 136        match self {
 137            Self::Custom(block) => f.debug_struct("Custom").field("block", block).finish(),
 138            Self::ExcerptHeader { buffer, .. } => f
 139                .debug_struct("ExcerptHeader")
 140                .field("path", &buffer.file().map(|f| f.path()))
 141                .finish(),
 142        }
 143    }
 144}
 145
 146#[derive(Clone, Debug, Default)]
 147struct TransformSummary {
 148    input_rows: u32,
 149    output_rows: u32,
 150}
 151
 152pub struct BlockChunks<'a> {
 153    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 154    input_chunks: wrap_map::WrapChunks<'a>,
 155    input_chunk: Chunk<'a>,
 156    output_row: u32,
 157    max_output_row: u32,
 158}
 159
 160#[derive(Clone)]
 161pub struct BlockBufferRows<'a> {
 162    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 163    input_buffer_rows: wrap_map::WrapBufferRows<'a>,
 164    output_row: u32,
 165    started: bool,
 166}
 167
 168impl BlockMap {
 169    pub fn new(
 170        wrap_snapshot: WrapSnapshot,
 171        buffer_header_height: u8,
 172        excerpt_header_height: u8,
 173    ) -> Self {
 174        let row_count = wrap_snapshot.max_point().row() + 1;
 175        let map = Self {
 176            next_block_id: AtomicUsize::new(0),
 177            blocks: Vec::new(),
 178            transforms: RefCell::new(SumTree::from_item(Transform::isomorphic(row_count), &())),
 179            wrap_snapshot: RefCell::new(wrap_snapshot.clone()),
 180            buffer_header_height,
 181            excerpt_header_height,
 182        };
 183        map.sync(
 184            &wrap_snapshot,
 185            Patch::new(vec![Edit {
 186                old: 0..row_count,
 187                new: 0..row_count,
 188            }]),
 189        );
 190        map
 191    }
 192
 193    pub fn read(&self, wrap_snapshot: WrapSnapshot, edits: Patch<u32>) -> BlockSnapshot {
 194        self.sync(&wrap_snapshot, edits);
 195        *self.wrap_snapshot.borrow_mut() = wrap_snapshot.clone();
 196        BlockSnapshot {
 197            wrap_snapshot,
 198            transforms: self.transforms.borrow().clone(),
 199        }
 200    }
 201
 202    pub fn write(&mut self, wrap_snapshot: WrapSnapshot, edits: Patch<u32>) -> BlockMapWriter {
 203        self.sync(&wrap_snapshot, edits);
 204        *self.wrap_snapshot.borrow_mut() = wrap_snapshot;
 205        BlockMapWriter(self)
 206    }
 207
 208    fn sync(&self, wrap_snapshot: &WrapSnapshot, mut edits: Patch<u32>) {
 209        let buffer = wrap_snapshot.buffer_snapshot();
 210
 211        // Handle changing the last excerpt if it is empty.
 212        if buffer.trailing_excerpt_update_count()
 213            != self
 214                .wrap_snapshot
 215                .borrow()
 216                .buffer_snapshot()
 217                .trailing_excerpt_update_count()
 218        {
 219            let max_point = wrap_snapshot.max_point();
 220            let edit_start = wrap_snapshot.prev_row_boundary(max_point);
 221            let edit_end = max_point.row() + 1;
 222            edits = edits.compose([WrapEdit {
 223                old: edit_start..edit_end,
 224                new: edit_start..edit_end,
 225            }]);
 226        }
 227
 228        let edits = edits.into_inner();
 229        if edits.is_empty() {
 230            return;
 231        }
 232
 233        let mut transforms = self.transforms.borrow_mut();
 234        let mut new_transforms = SumTree::new();
 235        let old_row_count = transforms.summary().input_rows;
 236        let new_row_count = wrap_snapshot.max_point().row() + 1;
 237        let mut cursor = transforms.cursor::<WrapRow>();
 238        let mut last_block_ix = 0;
 239        let mut blocks_in_edit = Vec::new();
 240        let mut edits = edits.into_iter().peekable();
 241
 242        while let Some(edit) = edits.next() {
 243            // Preserve any old transforms that precede this edit.
 244            let old_start = WrapRow(edit.old.start);
 245            let new_start = WrapRow(edit.new.start);
 246            new_transforms.push_tree(cursor.slice(&old_start, Bias::Left, &()), &());
 247            if let Some(transform) = cursor.item() {
 248                if transform.is_isomorphic() && old_start == cursor.end(&()) {
 249                    new_transforms.push(transform.clone(), &());
 250                    cursor.next(&());
 251                    while let Some(transform) = cursor.item() {
 252                        if transform
 253                            .block
 254                            .as_ref()
 255                            .map_or(false, |b| b.disposition().is_below())
 256                        {
 257                            new_transforms.push(transform.clone(), &());
 258                            cursor.next(&());
 259                        } else {
 260                            break;
 261                        }
 262                    }
 263                }
 264            }
 265
 266            // Preserve any portion of an old transform that precedes this edit.
 267            let extent_before_edit = old_start.0 - cursor.start().0;
 268            push_isomorphic(&mut new_transforms, extent_before_edit);
 269
 270            // Skip over any old transforms that intersect this edit.
 271            let mut old_end = WrapRow(edit.old.end);
 272            let mut new_end = WrapRow(edit.new.end);
 273            cursor.seek(&old_end, Bias::Left, &());
 274            cursor.next(&());
 275            if old_end == *cursor.start() {
 276                while let Some(transform) = cursor.item() {
 277                    if transform
 278                        .block
 279                        .as_ref()
 280                        .map_or(false, |b| b.disposition().is_below())
 281                    {
 282                        cursor.next(&());
 283                    } else {
 284                        break;
 285                    }
 286                }
 287            }
 288
 289            // Combine this edit with any subsequent edits that intersect the same transform.
 290            while let Some(next_edit) = edits.peek() {
 291                if next_edit.old.start <= cursor.start().0 {
 292                    old_end = WrapRow(next_edit.old.end);
 293                    new_end = WrapRow(next_edit.new.end);
 294                    cursor.seek(&old_end, Bias::Left, &());
 295                    cursor.next(&());
 296                    if old_end == *cursor.start() {
 297                        while let Some(transform) = cursor.item() {
 298                            if transform
 299                                .block
 300                                .as_ref()
 301                                .map_or(false, |b| b.disposition().is_below())
 302                            {
 303                                cursor.next(&());
 304                            } else {
 305                                break;
 306                            }
 307                        }
 308                    }
 309                    edits.next();
 310                } else {
 311                    break;
 312                }
 313            }
 314
 315            // Find the blocks within this edited region.
 316            let new_buffer_start =
 317                wrap_snapshot.to_point(WrapPoint::new(new_start.0, 0), Bias::Left);
 318            let start_bound = Bound::Included(new_buffer_start);
 319            let start_block_ix = match self.blocks[last_block_ix..].binary_search_by(|probe| {
 320                probe
 321                    .position
 322                    .to_point(buffer)
 323                    .cmp(&new_buffer_start)
 324                    .then(Ordering::Greater)
 325            }) {
 326                Ok(ix) | Err(ix) => last_block_ix + ix,
 327            };
 328
 329            let end_bound;
 330            let end_block_ix = if new_end.0 > wrap_snapshot.max_point().row() {
 331                end_bound = Bound::Unbounded;
 332                self.blocks.len()
 333            } else {
 334                let new_buffer_end =
 335                    wrap_snapshot.to_point(WrapPoint::new(new_end.0, 0), Bias::Left);
 336                end_bound = Bound::Excluded(new_buffer_end);
 337                match self.blocks[start_block_ix..].binary_search_by(|probe| {
 338                    probe
 339                        .position
 340                        .to_point(buffer)
 341                        .cmp(&new_buffer_end)
 342                        .then(Ordering::Greater)
 343                }) {
 344                    Ok(ix) | Err(ix) => start_block_ix + ix,
 345                }
 346            };
 347            last_block_ix = end_block_ix;
 348
 349            debug_assert!(blocks_in_edit.is_empty());
 350            blocks_in_edit.extend(
 351                self.blocks[start_block_ix..end_block_ix]
 352                    .iter()
 353                    .map(|block| {
 354                        let mut position = block.position.to_point(buffer);
 355                        match block.disposition {
 356                            BlockDisposition::Above => position.column = 0,
 357                            BlockDisposition::Below => {
 358                                position.column = buffer.line_len(position.row)
 359                            }
 360                        }
 361                        let position = wrap_snapshot.make_wrap_point(position, Bias::Left);
 362                        (position.row(), TransformBlock::Custom(block.clone()))
 363                    }),
 364            );
 365            blocks_in_edit.extend(
 366                buffer
 367                    .excerpt_boundaries_in_range((start_bound, end_bound))
 368                    .map(|excerpt_boundary| {
 369                        (
 370                            wrap_snapshot
 371                                .make_wrap_point(Point::new(excerpt_boundary.row, 0), Bias::Left)
 372                                .row(),
 373                            TransformBlock::ExcerptHeader {
 374                                id: excerpt_boundary.id,
 375                                buffer: excerpt_boundary.buffer,
 376                                range: excerpt_boundary.range,
 377                                height: if excerpt_boundary.starts_new_buffer {
 378                                    self.buffer_header_height
 379                                } else {
 380                                    self.excerpt_header_height
 381                                },
 382                                starts_new_buffer: excerpt_boundary.starts_new_buffer,
 383                            },
 384                        )
 385                    }),
 386            );
 387
 388            // Place excerpt headers above custom blocks on the same row.
 389            blocks_in_edit.sort_unstable_by(|(row_a, block_a), (row_b, block_b)| {
 390                row_a.cmp(row_b).then_with(|| match (block_a, block_b) {
 391                    (
 392                        TransformBlock::ExcerptHeader { .. },
 393                        TransformBlock::ExcerptHeader { .. },
 394                    ) => Ordering::Equal,
 395                    (TransformBlock::ExcerptHeader { .. }, _) => Ordering::Less,
 396                    (_, TransformBlock::ExcerptHeader { .. }) => Ordering::Greater,
 397                    (TransformBlock::Custom(block_a), TransformBlock::Custom(block_b)) => block_a
 398                        .disposition
 399                        .cmp(&block_b.disposition)
 400                        .then_with(|| block_a.id.cmp(&block_b.id)),
 401                })
 402            });
 403
 404            // For each of these blocks, insert a new isomorphic transform preceding the block,
 405            // and then insert the block itself.
 406            for (block_row, block) in blocks_in_edit.drain(..) {
 407                let insertion_row = match block.disposition() {
 408                    BlockDisposition::Above => block_row,
 409                    BlockDisposition::Below => block_row + 1,
 410                };
 411                let extent_before_block = insertion_row - new_transforms.summary().input_rows;
 412                push_isomorphic(&mut new_transforms, extent_before_block);
 413                new_transforms.push(Transform::block(block), &());
 414            }
 415
 416            old_end = WrapRow(old_end.0.min(old_row_count));
 417            new_end = WrapRow(new_end.0.min(new_row_count));
 418
 419            // Insert an isomorphic transform after the final block.
 420            let extent_after_last_block = new_end.0 - new_transforms.summary().input_rows;
 421            push_isomorphic(&mut new_transforms, extent_after_last_block);
 422
 423            // Preserve any portion of the old transform after this edit.
 424            let extent_after_edit = cursor.start().0 - old_end.0;
 425            push_isomorphic(&mut new_transforms, extent_after_edit);
 426        }
 427
 428        new_transforms.push_tree(cursor.suffix(&()), &());
 429        debug_assert_eq!(
 430            new_transforms.summary().input_rows,
 431            wrap_snapshot.max_point().row() + 1
 432        );
 433
 434        drop(cursor);
 435        *transforms = new_transforms;
 436    }
 437
 438    pub fn replace(&mut self, mut renderers: HashMap<BlockId, RenderBlock>) {
 439        for block in &self.blocks {
 440            if let Some(render) = renderers.remove(&block.id) {
 441                *block.render.lock() = render;
 442            }
 443        }
 444    }
 445}
 446
 447fn push_isomorphic(tree: &mut SumTree<Transform>, rows: u32) {
 448    if rows == 0 {
 449        return;
 450    }
 451
 452    let mut extent = Some(rows);
 453    tree.update_last(
 454        |last_transform| {
 455            if last_transform.is_isomorphic() {
 456                let extent = extent.take().unwrap();
 457                last_transform.summary.input_rows += extent;
 458                last_transform.summary.output_rows += extent;
 459            }
 460        },
 461        &(),
 462    );
 463    if let Some(extent) = extent {
 464        tree.push(Transform::isomorphic(extent), &());
 465    }
 466}
 467
 468impl BlockPoint {
 469    pub fn new(row: u32, column: u32) -> Self {
 470        Self(Point::new(row, column))
 471    }
 472}
 473
 474impl Deref for BlockPoint {
 475    type Target = Point;
 476
 477    fn deref(&self) -> &Self::Target {
 478        &self.0
 479    }
 480}
 481
 482impl std::ops::DerefMut for BlockPoint {
 483    fn deref_mut(&mut self) -> &mut Self::Target {
 484        &mut self.0
 485    }
 486}
 487
 488impl<'a> BlockMapWriter<'a> {
 489    pub fn insert(
 490        &mut self,
 491        blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
 492    ) -> Vec<BlockId> {
 493        let mut ids = Vec::new();
 494        let mut edits = Patch::default();
 495        let wrap_snapshot = &*self.0.wrap_snapshot.borrow();
 496        let buffer = wrap_snapshot.buffer_snapshot();
 497
 498        for block in blocks {
 499            let id = BlockId(self.0.next_block_id.fetch_add(1, SeqCst));
 500            ids.push(id);
 501
 502            let position = block.position;
 503            let point = position.to_point(buffer);
 504            let wrap_row = wrap_snapshot
 505                .make_wrap_point(Point::new(point.row, 0), Bias::Left)
 506                .row();
 507            let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 508            let end_row = wrap_snapshot
 509                .next_row_boundary(WrapPoint::new(wrap_row, 0))
 510                .unwrap_or(wrap_snapshot.max_point().row() + 1);
 511
 512            let block_ix = match self
 513                .0
 514                .blocks
 515                .binary_search_by(|probe| probe.position.cmp(&position, buffer))
 516            {
 517                Ok(ix) | Err(ix) => ix,
 518            };
 519            self.0.blocks.insert(
 520                block_ix,
 521                Arc::new(Block {
 522                    id,
 523                    position,
 524                    height: block.height,
 525                    render: Mutex::new(block.render),
 526                    disposition: block.disposition,
 527                    style: block.style,
 528                }),
 529            );
 530
 531            edits = edits.compose([Edit {
 532                old: start_row..end_row,
 533                new: start_row..end_row,
 534            }]);
 535        }
 536
 537        self.0.sync(wrap_snapshot, edits);
 538        ids
 539    }
 540
 541    pub fn remove(&mut self, block_ids: HashSet<BlockId>) {
 542        let wrap_snapshot = &*self.0.wrap_snapshot.borrow();
 543        let buffer = wrap_snapshot.buffer_snapshot();
 544        let mut edits = Patch::default();
 545        let mut last_block_buffer_row = None;
 546        self.0.blocks.retain(|block| {
 547            if block_ids.contains(&block.id) {
 548                let buffer_row = block.position.to_point(buffer).row;
 549                if last_block_buffer_row != Some(buffer_row) {
 550                    last_block_buffer_row = Some(buffer_row);
 551                    let wrap_row = wrap_snapshot
 552                        .make_wrap_point(Point::new(buffer_row, 0), Bias::Left)
 553                        .row();
 554                    let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 555                    let end_row = wrap_snapshot
 556                        .next_row_boundary(WrapPoint::new(wrap_row, 0))
 557                        .unwrap_or(wrap_snapshot.max_point().row() + 1);
 558                    edits.push(Edit {
 559                        old: start_row..end_row,
 560                        new: start_row..end_row,
 561                    })
 562                }
 563                false
 564            } else {
 565                true
 566            }
 567        });
 568        self.0.sync(wrap_snapshot, edits);
 569    }
 570}
 571
 572impl BlockSnapshot {
 573    #[cfg(test)]
 574    pub fn text(&self) -> String {
 575        self.chunks(0..self.transforms.summary().output_rows, false, None)
 576            .map(|chunk| chunk.text)
 577            .collect()
 578    }
 579
 580    pub fn chunks<'a>(
 581        &'a self,
 582        rows: Range<u32>,
 583        language_aware: bool,
 584        text_highlights: Option<&'a TextHighlights>,
 585    ) -> BlockChunks<'a> {
 586        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 587        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 588        let input_end = {
 589            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 590            let overshoot = if cursor
 591                .item()
 592                .map_or(false, |transform| transform.is_isomorphic())
 593            {
 594                rows.end - cursor.start().0 .0
 595            } else {
 596                0
 597            };
 598            cursor.start().1 .0 + overshoot
 599        };
 600        let input_start = {
 601            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 602            let overshoot = if cursor
 603                .item()
 604                .map_or(false, |transform| transform.is_isomorphic())
 605            {
 606                rows.start - cursor.start().0 .0
 607            } else {
 608                0
 609            };
 610            cursor.start().1 .0 + overshoot
 611        };
 612        BlockChunks {
 613            input_chunks: self.wrap_snapshot.chunks(
 614                input_start..input_end,
 615                language_aware,
 616                text_highlights,
 617            ),
 618            input_chunk: Default::default(),
 619            transforms: cursor,
 620            output_row: rows.start,
 621            max_output_row,
 622        }
 623    }
 624
 625    pub fn buffer_rows(&self, start_row: u32) -> BlockBufferRows {
 626        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 627        cursor.seek(&BlockRow(start_row), Bias::Right, &());
 628        let (output_start, input_start) = cursor.start();
 629        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 630            start_row - output_start.0
 631        } else {
 632            0
 633        };
 634        let input_start_row = input_start.0 + overshoot;
 635        BlockBufferRows {
 636            transforms: cursor,
 637            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 638            output_row: start_row,
 639            started: false,
 640        }
 641    }
 642
 643    pub fn blocks_in_range(
 644        &self,
 645        rows: Range<u32>,
 646    ) -> impl Iterator<Item = (u32, &TransformBlock)> {
 647        let mut cursor = self.transforms.cursor::<BlockRow>();
 648        cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 649        std::iter::from_fn(move || {
 650            while let Some(transform) = cursor.item() {
 651                let start_row = cursor.start().0;
 652                if start_row >= rows.end {
 653                    break;
 654                }
 655                if let Some(block) = &transform.block {
 656                    cursor.next(&());
 657                    return Some((start_row, block));
 658                } else {
 659                    cursor.next(&());
 660                }
 661            }
 662            None
 663        })
 664    }
 665
 666    pub fn max_point(&self) -> BlockPoint {
 667        let row = self.transforms.summary().output_rows - 1;
 668        BlockPoint::new(row, self.line_len(row))
 669    }
 670
 671    pub fn longest_row(&self) -> u32 {
 672        let input_row = self.wrap_snapshot.longest_row();
 673        self.to_block_point(WrapPoint::new(input_row, 0)).row
 674    }
 675
 676    pub fn line_len(&self, row: u32) -> u32 {
 677        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 678        cursor.seek(&BlockRow(row), Bias::Right, &());
 679        if let Some(transform) = cursor.item() {
 680            let (output_start, input_start) = cursor.start();
 681            let overshoot = row - output_start.0;
 682            if transform.block.is_some() {
 683                0
 684            } else {
 685                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 686            }
 687        } else {
 688            panic!("row out of range");
 689        }
 690    }
 691
 692    pub fn is_block_line(&self, row: u32) -> bool {
 693        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 694        cursor.seek(&BlockRow(row), Bias::Right, &());
 695        cursor.item().map_or(false, |t| t.block.is_some())
 696    }
 697
 698    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 699        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 700        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 701
 702        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 703        let mut search_left =
 704            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 705        let mut reversed = false;
 706
 707        loop {
 708            if let Some(transform) = cursor.item() {
 709                if transform.is_isomorphic() {
 710                    let (output_start_row, input_start_row) = cursor.start();
 711                    let (output_end_row, input_end_row) = cursor.end(&());
 712                    let output_start = Point::new(output_start_row.0, 0);
 713                    let input_start = Point::new(input_start_row.0, 0);
 714                    let input_end = Point::new(input_end_row.0, 0);
 715                    let input_point = if point.row >= output_end_row.0 {
 716                        let line_len = self.wrap_snapshot.line_len(input_end_row.0 - 1);
 717                        self.wrap_snapshot
 718                            .clip_point(WrapPoint::new(input_end_row.0 - 1, line_len), bias)
 719                    } else {
 720                        let output_overshoot = point.0.saturating_sub(output_start);
 721                        self.wrap_snapshot
 722                            .clip_point(WrapPoint(input_start + output_overshoot), bias)
 723                    };
 724
 725                    if (input_start..input_end).contains(&input_point.0) {
 726                        let input_overshoot = input_point.0.saturating_sub(input_start);
 727                        return BlockPoint(output_start + input_overshoot);
 728                    }
 729                }
 730
 731                if search_left {
 732                    cursor.prev(&());
 733                } else {
 734                    cursor.next(&());
 735                }
 736            } else if reversed {
 737                return self.max_point();
 738            } else {
 739                reversed = true;
 740                search_left = !search_left;
 741                cursor.seek(&BlockRow(point.row), Bias::Right, &());
 742            }
 743        }
 744    }
 745
 746    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 747        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 748        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 749        if let Some(transform) = cursor.item() {
 750            debug_assert!(transform.is_isomorphic());
 751        } else {
 752            return self.max_point();
 753        }
 754
 755        let (input_start_row, output_start_row) = cursor.start();
 756        let input_start = Point::new(input_start_row.0, 0);
 757        let output_start = Point::new(output_start_row.0, 0);
 758        let input_overshoot = wrap_point.0 - input_start;
 759        BlockPoint(output_start + input_overshoot)
 760    }
 761
 762    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 763        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 764        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 765        if let Some(transform) = cursor.item() {
 766            match transform.block.as_ref().map(|b| b.disposition()) {
 767                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 768                Some(BlockDisposition::Below) => {
 769                    let wrap_row = cursor.start().1 .0 - 1;
 770                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
 771                }
 772                None => {
 773                    let overshoot = block_point.row - cursor.start().0 .0;
 774                    let wrap_row = cursor.start().1 .0 + overshoot;
 775                    WrapPoint::new(wrap_row, block_point.column)
 776                }
 777            }
 778        } else {
 779            self.wrap_snapshot.max_point()
 780        }
 781    }
 782}
 783
 784impl Transform {
 785    fn isomorphic(rows: u32) -> Self {
 786        Self {
 787            summary: TransformSummary {
 788                input_rows: rows,
 789                output_rows: rows,
 790            },
 791            block: None,
 792        }
 793    }
 794
 795    fn block(block: TransformBlock) -> Self {
 796        Self {
 797            summary: TransformSummary {
 798                input_rows: 0,
 799                output_rows: block.height() as u32,
 800            },
 801            block: Some(block),
 802        }
 803    }
 804
 805    fn is_isomorphic(&self) -> bool {
 806        self.block.is_none()
 807    }
 808}
 809
 810impl<'a> Iterator for BlockChunks<'a> {
 811    type Item = Chunk<'a>;
 812
 813    fn next(&mut self) -> Option<Self::Item> {
 814        if self.output_row >= self.max_output_row {
 815            return None;
 816        }
 817
 818        let transform = self.transforms.item()?;
 819        if transform.block.is_some() {
 820            let block_start = self.transforms.start().0 .0;
 821            let mut block_end = self.transforms.end(&()).0 .0;
 822            self.transforms.next(&());
 823            if self.transforms.item().is_none() {
 824                block_end -= 1;
 825            }
 826
 827            let start_in_block = self.output_row - block_start;
 828            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
 829            let line_count = end_in_block - start_in_block;
 830            self.output_row += line_count;
 831
 832            return Some(Chunk {
 833                text: unsafe { std::str::from_utf8_unchecked(&NEWLINES[..line_count as usize]) },
 834                syntax_highlight_id: None,
 835                highlight_style: None,
 836                diagnostic_severity: None,
 837                is_unnecessary: false,
 838            });
 839        }
 840
 841        if self.input_chunk.text.is_empty() {
 842            if let Some(input_chunk) = self.input_chunks.next() {
 843                self.input_chunk = input_chunk;
 844            } else {
 845                self.output_row += 1;
 846                if self.output_row < self.max_output_row {
 847                    self.transforms.next(&());
 848                    return Some(Chunk {
 849                        text: "\n",
 850                        ..Default::default()
 851                    });
 852                } else {
 853                    return None;
 854                }
 855            }
 856        }
 857
 858        let transform_end = self.transforms.end(&()).0 .0;
 859        let (prefix_rows, prefix_bytes) =
 860            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
 861        self.output_row += prefix_rows;
 862        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
 863        self.input_chunk.text = suffix;
 864        if self.output_row == transform_end {
 865            self.transforms.next(&());
 866        }
 867
 868        Some(Chunk {
 869            text: prefix,
 870            ..self.input_chunk
 871        })
 872    }
 873}
 874
 875impl<'a> Iterator for BlockBufferRows<'a> {
 876    type Item = Option<u32>;
 877
 878    fn next(&mut self) -> Option<Self::Item> {
 879        if self.started {
 880            self.output_row += 1;
 881        } else {
 882            self.started = true;
 883        }
 884
 885        if self.output_row >= self.transforms.end(&()).0 .0 {
 886            self.transforms.next(&());
 887        }
 888
 889        let transform = self.transforms.item()?;
 890        if transform.block.is_some() {
 891            Some(None)
 892        } else {
 893            Some(self.input_buffer_rows.next().unwrap())
 894        }
 895    }
 896}
 897
 898impl sum_tree::Item for Transform {
 899    type Summary = TransformSummary;
 900
 901    fn summary(&self) -> Self::Summary {
 902        self.summary.clone()
 903    }
 904}
 905
 906impl sum_tree::Summary for TransformSummary {
 907    type Context = ();
 908
 909    fn add_summary(&mut self, summary: &Self, _: &()) {
 910        self.input_rows += summary.input_rows;
 911        self.output_rows += summary.output_rows;
 912    }
 913}
 914
 915impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
 916    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 917        self.0 += summary.input_rows;
 918    }
 919}
 920
 921impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
 922    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 923        self.0 += summary.output_rows;
 924    }
 925}
 926
 927impl BlockDisposition {
 928    fn is_below(&self) -> bool {
 929        matches!(self, BlockDisposition::Below)
 930    }
 931}
 932
 933impl<'a, 'b> Deref for BlockContext<'a, 'b> {
 934    type Target = RenderContext<'a, crate::Editor>;
 935
 936    fn deref(&self) -> &Self::Target {
 937        self.cx
 938    }
 939}
 940
 941impl<'a, 'b> DerefMut for BlockContext<'a, 'b> {
 942    fn deref_mut(&mut self) -> &mut Self::Target {
 943        self.cx
 944    }
 945}
 946
 947impl Block {
 948    pub fn render(&self, cx: &mut BlockContext) -> ElementBox {
 949        self.render.lock()(cx)
 950    }
 951
 952    pub fn position(&self) -> &Anchor {
 953        &self.position
 954    }
 955
 956    pub fn style(&self) -> BlockStyle {
 957        self.style
 958    }
 959}
 960
 961impl Debug for Block {
 962    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 963        f.debug_struct("Block")
 964            .field("id", &self.id)
 965            .field("position", &self.position)
 966            .field("disposition", &self.disposition)
 967            .finish()
 968    }
 969}
 970
 971// Count the number of bytes prior to a target point. If the string doesn't contain the target
 972// point, return its total extent. Otherwise return the target point itself.
 973fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 974    let mut row = 0;
 975    let mut offset = 0;
 976    for (ix, line) in s.split('\n').enumerate() {
 977        if ix > 0 {
 978            row += 1;
 979            offset += 1;
 980        }
 981        if row >= target {
 982            break;
 983        }
 984        offset += line.len() as usize;
 985    }
 986    (row, offset)
 987}
 988
 989#[cfg(test)]
 990mod tests {
 991    use super::*;
 992    use crate::display_map::{fold_map::FoldMap, tab_map::TabMap, wrap_map::WrapMap};
 993    use crate::multi_buffer::MultiBuffer;
 994    use gpui::{elements::Empty, Element};
 995    use rand::prelude::*;
 996    use settings::Settings;
 997    use std::env;
 998    use util::RandomCharIter;
 999
1000    #[gpui::test]
1001    fn test_offset_for_row() {
1002        assert_eq!(offset_for_row("", 0), (0, 0));
1003        assert_eq!(offset_for_row("", 1), (0, 0));
1004        assert_eq!(offset_for_row("abcd", 0), (0, 0));
1005        assert_eq!(offset_for_row("abcd", 1), (0, 4));
1006        assert_eq!(offset_for_row("\n", 0), (0, 0));
1007        assert_eq!(offset_for_row("\n", 1), (1, 1));
1008        assert_eq!(offset_for_row("abc\ndef\nghi", 0), (0, 0));
1009        assert_eq!(offset_for_row("abc\ndef\nghi", 1), (1, 4));
1010        assert_eq!(offset_for_row("abc\ndef\nghi", 2), (2, 8));
1011        assert_eq!(offset_for_row("abc\ndef\nghi", 3), (2, 11));
1012    }
1013
1014    #[gpui::test]
1015    fn test_basic_blocks(cx: &mut gpui::MutableAppContext) {
1016        cx.set_global(Settings::test(cx));
1017
1018        let family_id = cx
1019            .font_cache()
1020            .load_family(&["Helvetica"], Default::default())
1021            .unwrap();
1022        let font_id = cx
1023            .font_cache()
1024            .select_font(family_id, &Default::default())
1025            .unwrap();
1026
1027        let text = "aaa\nbbb\nccc\nddd";
1028
1029        let buffer = MultiBuffer::build_simple(text, cx);
1030        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1031        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1032        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1033        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot, 1.try_into().unwrap());
1034        let (wrap_map, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, None, cx);
1035        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1, 1);
1036
1037        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1038        let block_ids = writer.insert(vec![
1039            BlockProperties {
1040                style: BlockStyle::Fixed,
1041                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
1042                height: 1,
1043                disposition: BlockDisposition::Above,
1044                render: Arc::new(|_| Empty::new().named("block 1")),
1045            },
1046            BlockProperties {
1047                style: BlockStyle::Fixed,
1048                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
1049                height: 2,
1050                disposition: BlockDisposition::Above,
1051                render: Arc::new(|_| Empty::new().named("block 2")),
1052            },
1053            BlockProperties {
1054                style: BlockStyle::Fixed,
1055                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
1056                height: 3,
1057                disposition: BlockDisposition::Below,
1058                render: Arc::new(|_| Empty::new().named("block 3")),
1059            },
1060        ]);
1061
1062        let snapshot = block_map.read(wraps_snapshot, Default::default());
1063        assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
1064
1065        let blocks = snapshot
1066            .blocks_in_range(0..8)
1067            .map(|(start_row, block)| {
1068                let block = block.as_custom().unwrap();
1069                (start_row..start_row + block.height as u32, block.id)
1070            })
1071            .collect::<Vec<_>>();
1072
1073        // When multiple blocks are on the same line, the newer blocks appear first.
1074        assert_eq!(
1075            blocks,
1076            &[
1077                (1..2, block_ids[0]),
1078                (2..4, block_ids[1]),
1079                (7..10, block_ids[2]),
1080            ]
1081        );
1082
1083        assert_eq!(
1084            snapshot.to_block_point(WrapPoint::new(0, 3)),
1085            BlockPoint::new(0, 3)
1086        );
1087        assert_eq!(
1088            snapshot.to_block_point(WrapPoint::new(1, 0)),
1089            BlockPoint::new(4, 0)
1090        );
1091        assert_eq!(
1092            snapshot.to_block_point(WrapPoint::new(3, 3)),
1093            BlockPoint::new(6, 3)
1094        );
1095
1096        assert_eq!(
1097            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
1098            WrapPoint::new(0, 3)
1099        );
1100        assert_eq!(
1101            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
1102            WrapPoint::new(1, 0)
1103        );
1104        assert_eq!(
1105            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
1106            WrapPoint::new(1, 0)
1107        );
1108        assert_eq!(
1109            snapshot.to_wrap_point(BlockPoint::new(7, 0)),
1110            WrapPoint::new(3, 3)
1111        );
1112
1113        assert_eq!(
1114            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
1115            BlockPoint::new(0, 3)
1116        );
1117        assert_eq!(
1118            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
1119            BlockPoint::new(4, 0)
1120        );
1121        assert_eq!(
1122            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1123            BlockPoint::new(0, 3)
1124        );
1125        assert_eq!(
1126            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1127            BlockPoint::new(4, 0)
1128        );
1129        assert_eq!(
1130            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Left),
1131            BlockPoint::new(4, 0)
1132        );
1133        assert_eq!(
1134            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Right),
1135            BlockPoint::new(4, 0)
1136        );
1137        assert_eq!(
1138            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Left),
1139            BlockPoint::new(6, 3)
1140        );
1141        assert_eq!(
1142            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Right),
1143            BlockPoint::new(6, 3)
1144        );
1145        assert_eq!(
1146            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Left),
1147            BlockPoint::new(6, 3)
1148        );
1149        assert_eq!(
1150            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Right),
1151            BlockPoint::new(6, 3)
1152        );
1153
1154        assert_eq!(
1155            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1156            &[
1157                Some(0),
1158                None,
1159                None,
1160                None,
1161                Some(1),
1162                Some(2),
1163                Some(3),
1164                None,
1165                None,
1166                None
1167            ]
1168        );
1169
1170        // Insert a line break, separating two block decorations into separate lines.
1171        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1172            buffer.edit([(Point::new(1, 1)..Point::new(1, 1), "!!!\n")], None, cx);
1173            buffer.snapshot(cx)
1174        });
1175
1176        let (folds_snapshot, fold_edits) =
1177            fold_map.read(buffer_snapshot, subscription.consume().into_inner());
1178        let (tabs_snapshot, tab_edits) =
1179            tab_map.sync(folds_snapshot, fold_edits, 4.try_into().unwrap());
1180        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1181            wrap_map.sync(tabs_snapshot, tab_edits, cx)
1182        });
1183        let snapshot = block_map.read(wraps_snapshot, wrap_edits);
1184        assert_eq!(snapshot.text(), "aaa\n\nb!!!\n\n\nbb\nccc\nddd\n\n\n");
1185    }
1186
1187    #[gpui::test]
1188    fn test_blocks_on_wrapped_lines(cx: &mut gpui::MutableAppContext) {
1189        cx.set_global(Settings::test(cx));
1190
1191        let family_id = cx
1192            .font_cache()
1193            .load_family(&["Helvetica"], Default::default())
1194            .unwrap();
1195        let font_id = cx
1196            .font_cache()
1197            .select_font(family_id, &Default::default())
1198            .unwrap();
1199
1200        let text = "one two three\nfour five six\nseven eight";
1201
1202        let buffer = MultiBuffer::build_simple(text, cx);
1203        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1204        let (_, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1205        let (_, tabs_snapshot) = TabMap::new(folds_snapshot, 1.try_into().unwrap());
1206        let (_, wraps_snapshot) = WrapMap::new(tabs_snapshot, font_id, 14.0, Some(60.), cx);
1207        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1, 1);
1208
1209        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1210        writer.insert(vec![
1211            BlockProperties {
1212                style: BlockStyle::Fixed,
1213                position: buffer_snapshot.anchor_after(Point::new(1, 12)),
1214                disposition: BlockDisposition::Above,
1215                render: Arc::new(|_| Empty::new().named("block 1")),
1216                height: 1,
1217            },
1218            BlockProperties {
1219                style: BlockStyle::Fixed,
1220                position: buffer_snapshot.anchor_after(Point::new(1, 1)),
1221                disposition: BlockDisposition::Below,
1222                render: Arc::new(|_| Empty::new().named("block 2")),
1223                height: 1,
1224            },
1225        ]);
1226
1227        // Blocks with an 'above' disposition go above their corresponding buffer line.
1228        // Blocks with a 'below' disposition go below their corresponding buffer line.
1229        let snapshot = block_map.read(wraps_snapshot, Default::default());
1230        assert_eq!(
1231            snapshot.text(),
1232            "one two \nthree\n\nfour five \nsix\n\nseven \neight"
1233        );
1234    }
1235
1236    #[gpui::test(iterations = 100)]
1237    fn test_random_blocks(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1238        cx.set_global(Settings::test(cx));
1239
1240        let operations = env::var("OPERATIONS")
1241            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1242            .unwrap_or(10);
1243
1244        let wrap_width = if rng.gen_bool(0.2) {
1245            None
1246        } else {
1247            Some(rng.gen_range(0.0..=100.0))
1248        };
1249        let tab_size = 1.try_into().unwrap();
1250        let family_id = cx
1251            .font_cache()
1252            .load_family(&["Helvetica"], Default::default())
1253            .unwrap();
1254        let font_id = cx
1255            .font_cache()
1256            .select_font(family_id, &Default::default())
1257            .unwrap();
1258        let font_size = 14.0;
1259        let buffer_start_header_height = rng.gen_range(1..=5);
1260        let excerpt_header_height = rng.gen_range(1..=5);
1261
1262        log::info!("Wrap width: {:?}", wrap_width);
1263        log::info!("Excerpt Header Height: {:?}", excerpt_header_height);
1264
1265        let buffer = if rng.gen() {
1266            let len = rng.gen_range(0..10);
1267            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1268            log::info!("initial buffer text: {:?}", text);
1269            MultiBuffer::build_simple(&text, cx)
1270        } else {
1271            MultiBuffer::build_random(&mut rng, cx)
1272        };
1273
1274        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1275        let (fold_map, folds_snapshot) = FoldMap::new(buffer_snapshot.clone());
1276        let (tab_map, tabs_snapshot) = TabMap::new(folds_snapshot, tab_size);
1277        let (wrap_map, wraps_snapshot) =
1278            WrapMap::new(tabs_snapshot, font_id, font_size, wrap_width, cx);
1279        let mut block_map = BlockMap::new(
1280            wraps_snapshot,
1281            buffer_start_header_height,
1282            excerpt_header_height,
1283        );
1284        let mut custom_blocks = Vec::new();
1285
1286        for _ in 0..operations {
1287            let mut buffer_edits = Vec::new();
1288            match rng.gen_range(0..=100) {
1289                0..=19 => {
1290                    let wrap_width = if rng.gen_bool(0.2) {
1291                        None
1292                    } else {
1293                        Some(rng.gen_range(0.0..=100.0))
1294                    };
1295                    log::info!("Setting wrap width to {:?}", wrap_width);
1296                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1297                }
1298                20..=39 => {
1299                    let block_count = rng.gen_range(1..=5);
1300                    let block_properties = (0..block_count)
1301                        .map(|_| {
1302                            let buffer = buffer.read(cx).read(cx);
1303                            let position = buffer.anchor_after(
1304                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1305                            );
1306
1307                            let disposition = if rng.gen() {
1308                                BlockDisposition::Above
1309                            } else {
1310                                BlockDisposition::Below
1311                            };
1312                            let height = rng.gen_range(1..5);
1313                            log::info!(
1314                                "inserting block {:?} {:?} with height {}",
1315                                disposition,
1316                                position.to_point(&buffer),
1317                                height
1318                            );
1319                            BlockProperties {
1320                                style: BlockStyle::Fixed,
1321                                position,
1322                                height,
1323                                disposition,
1324                                render: Arc::new(|_| Empty::new().boxed()),
1325                            }
1326                        })
1327                        .collect::<Vec<_>>();
1328
1329                    let (folds_snapshot, fold_edits) =
1330                        fold_map.read(buffer_snapshot.clone(), vec![]);
1331                    let (tabs_snapshot, tab_edits) =
1332                        tab_map.sync(folds_snapshot, fold_edits, tab_size);
1333                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1334                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1335                    });
1336                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1337                    let block_ids = block_map.insert(block_properties.clone());
1338                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1339                        custom_blocks.push((block_id, props));
1340                    }
1341                }
1342                40..=59 if !custom_blocks.is_empty() => {
1343                    let block_count = rng.gen_range(1..=4.min(custom_blocks.len()));
1344                    let block_ids_to_remove = (0..block_count)
1345                        .map(|_| {
1346                            custom_blocks
1347                                .remove(rng.gen_range(0..custom_blocks.len()))
1348                                .0
1349                        })
1350                        .collect();
1351
1352                    let (folds_snapshot, fold_edits) =
1353                        fold_map.read(buffer_snapshot.clone(), vec![]);
1354                    let (tabs_snapshot, tab_edits) =
1355                        tab_map.sync(folds_snapshot, fold_edits, tab_size);
1356                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1357                        wrap_map.sync(tabs_snapshot, tab_edits, cx)
1358                    });
1359                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1360                    block_map.remove(block_ids_to_remove);
1361                }
1362                _ => {
1363                    buffer.update(cx, |buffer, cx| {
1364                        let mutation_count = rng.gen_range(1..=5);
1365                        let subscription = buffer.subscribe();
1366                        buffer.randomly_mutate(&mut rng, mutation_count, cx);
1367                        buffer_snapshot = buffer.snapshot(cx);
1368                        buffer_edits.extend(subscription.consume());
1369                        log::info!("buffer text: {:?}", buffer_snapshot.text());
1370                    });
1371                }
1372            }
1373
1374            let (folds_snapshot, fold_edits) = fold_map.read(buffer_snapshot.clone(), buffer_edits);
1375            let (tabs_snapshot, tab_edits) = tab_map.sync(folds_snapshot, fold_edits, tab_size);
1376            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1377                wrap_map.sync(tabs_snapshot, tab_edits, cx)
1378            });
1379            let blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits);
1380            assert_eq!(
1381                blocks_snapshot.transforms.summary().input_rows,
1382                wraps_snapshot.max_point().row() + 1
1383            );
1384            log::info!("blocks text: {:?}", blocks_snapshot.text());
1385
1386            let mut expected_blocks = Vec::new();
1387            expected_blocks.extend(custom_blocks.iter().map(|(id, block)| {
1388                let mut position = block.position.to_point(&buffer_snapshot);
1389                match block.disposition {
1390                    BlockDisposition::Above => {
1391                        position.column = 0;
1392                    }
1393                    BlockDisposition::Below => {
1394                        position.column = buffer_snapshot.line_len(position.row);
1395                    }
1396                };
1397                let row = wraps_snapshot.make_wrap_point(position, Bias::Left).row();
1398                (
1399                    row,
1400                    ExpectedBlock::Custom {
1401                        disposition: block.disposition,
1402                        id: *id,
1403                        height: block.height,
1404                    },
1405                )
1406            }));
1407            expected_blocks.extend(buffer_snapshot.excerpt_boundaries_in_range(0..).map(
1408                |boundary| {
1409                    let position =
1410                        wraps_snapshot.make_wrap_point(Point::new(boundary.row, 0), Bias::Left);
1411                    (
1412                        position.row(),
1413                        ExpectedBlock::ExcerptHeader {
1414                            height: if boundary.starts_new_buffer {
1415                                buffer_start_header_height
1416                            } else {
1417                                excerpt_header_height
1418                            },
1419                            starts_new_buffer: boundary.starts_new_buffer,
1420                        },
1421                    )
1422                },
1423            ));
1424            expected_blocks.sort_unstable();
1425            let mut sorted_blocks_iter = expected_blocks.into_iter().peekable();
1426
1427            let input_buffer_rows = buffer_snapshot.buffer_rows(0).collect::<Vec<_>>();
1428            let mut expected_buffer_rows = Vec::new();
1429            let mut expected_text = String::new();
1430            let mut expected_block_positions = Vec::new();
1431            let input_text = wraps_snapshot.text();
1432            for (row, input_line) in input_text.split('\n').enumerate() {
1433                let row = row as u32;
1434                if row > 0 {
1435                    expected_text.push('\n');
1436                }
1437
1438                let buffer_row = input_buffer_rows[wraps_snapshot
1439                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1440                    .row as usize];
1441
1442                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1443                    if *block_row == row && block.disposition() == BlockDisposition::Above {
1444                        let (_, block) = sorted_blocks_iter.next().unwrap();
1445                        let height = block.height() as usize;
1446                        expected_block_positions
1447                            .push((expected_text.matches('\n').count() as u32, block));
1448                        let text = "\n".repeat(height);
1449                        expected_text.push_str(&text);
1450                        for _ in 0..height {
1451                            expected_buffer_rows.push(None);
1452                        }
1453                    } else {
1454                        break;
1455                    }
1456                }
1457
1458                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1459                expected_buffer_rows.push(if soft_wrapped { None } else { buffer_row });
1460                expected_text.push_str(input_line);
1461
1462                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1463                    if *block_row == row && block.disposition() == BlockDisposition::Below {
1464                        let (_, block) = sorted_blocks_iter.next().unwrap();
1465                        let height = block.height() as usize;
1466                        expected_block_positions
1467                            .push((expected_text.matches('\n').count() as u32 + 1, block));
1468                        let text = "\n".repeat(height);
1469                        expected_text.push_str(&text);
1470                        for _ in 0..height {
1471                            expected_buffer_rows.push(None);
1472                        }
1473                    } else {
1474                        break;
1475                    }
1476                }
1477            }
1478
1479            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1480            let expected_row_count = expected_lines.len();
1481            for start_row in 0..expected_row_count {
1482                let expected_text = expected_lines[start_row..].join("\n");
1483                let actual_text = blocks_snapshot
1484                    .chunks(
1485                        start_row as u32..blocks_snapshot.max_point().row + 1,
1486                        false,
1487                        None,
1488                    )
1489                    .map(|chunk| chunk.text)
1490                    .collect::<String>();
1491                assert_eq!(
1492                    actual_text, expected_text,
1493                    "incorrect text starting from row {}",
1494                    start_row
1495                );
1496                assert_eq!(
1497                    blocks_snapshot
1498                        .buffer_rows(start_row as u32)
1499                        .collect::<Vec<_>>(),
1500                    &expected_buffer_rows[start_row..]
1501                );
1502            }
1503
1504            assert_eq!(
1505                blocks_snapshot
1506                    .blocks_in_range(0..(expected_row_count as u32))
1507                    .map(|(row, block)| (row, block.clone().into()))
1508                    .collect::<Vec<_>>(),
1509                expected_block_positions
1510            );
1511
1512            let mut expected_longest_rows = Vec::new();
1513            let mut longest_line_len = -1_isize;
1514            for (row, line) in expected_lines.iter().enumerate() {
1515                let row = row as u32;
1516
1517                assert_eq!(
1518                    blocks_snapshot.line_len(row),
1519                    line.len() as u32,
1520                    "invalid line len for row {}",
1521                    row
1522                );
1523
1524                let line_char_count = line.chars().count() as isize;
1525                match line_char_count.cmp(&longest_line_len) {
1526                    Ordering::Less => {}
1527                    Ordering::Equal => expected_longest_rows.push(row),
1528                    Ordering::Greater => {
1529                        longest_line_len = line_char_count;
1530                        expected_longest_rows.clear();
1531                        expected_longest_rows.push(row);
1532                    }
1533                }
1534            }
1535
1536            let longest_row = blocks_snapshot.longest_row();
1537            assert!(
1538                expected_longest_rows.contains(&longest_row),
1539                "incorrect longest row {}. expected {:?} with length {}",
1540                longest_row,
1541                expected_longest_rows,
1542                longest_line_len,
1543            );
1544
1545            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1546                let wrap_point = WrapPoint::new(row, 0);
1547                let block_point = blocks_snapshot.to_block_point(wrap_point);
1548                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1549            }
1550
1551            let mut block_point = BlockPoint::new(0, 0);
1552            for c in expected_text.chars() {
1553                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1554                let left_buffer_point = blocks_snapshot.to_point(left_point, Bias::Left);
1555                assert_eq!(
1556                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1557                    left_point
1558                );
1559                assert_eq!(
1560                    left_buffer_point,
1561                    buffer_snapshot.clip_point(left_buffer_point, Bias::Right),
1562                    "{:?} is not valid in buffer coordinates",
1563                    left_point
1564                );
1565
1566                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1567                let right_buffer_point = blocks_snapshot.to_point(right_point, Bias::Right);
1568                assert_eq!(
1569                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1570                    right_point
1571                );
1572                assert_eq!(
1573                    right_buffer_point,
1574                    buffer_snapshot.clip_point(right_buffer_point, Bias::Left),
1575                    "{:?} is not valid in buffer coordinates",
1576                    right_point
1577                );
1578
1579                if c == '\n' {
1580                    block_point.0 += Point::new(1, 0);
1581                } else {
1582                    block_point.column += c.len_utf8() as u32;
1583                }
1584            }
1585        }
1586
1587        #[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
1588        enum ExpectedBlock {
1589            ExcerptHeader {
1590                height: u8,
1591                starts_new_buffer: bool,
1592            },
1593            Custom {
1594                disposition: BlockDisposition,
1595                id: BlockId,
1596                height: u8,
1597            },
1598        }
1599
1600        impl ExpectedBlock {
1601            fn height(&self) -> u8 {
1602                match self {
1603                    ExpectedBlock::ExcerptHeader { height, .. } => *height,
1604                    ExpectedBlock::Custom { height, .. } => *height,
1605                }
1606            }
1607
1608            fn disposition(&self) -> BlockDisposition {
1609                match self {
1610                    ExpectedBlock::ExcerptHeader { .. } => BlockDisposition::Above,
1611                    ExpectedBlock::Custom { disposition, .. } => *disposition,
1612                }
1613            }
1614        }
1615
1616        impl From<TransformBlock> for ExpectedBlock {
1617            fn from(block: TransformBlock) -> Self {
1618                match block {
1619                    TransformBlock::Custom(block) => ExpectedBlock::Custom {
1620                        id: block.id,
1621                        disposition: block.disposition,
1622                        height: block.height,
1623                    },
1624                    TransformBlock::ExcerptHeader {
1625                        height,
1626                        starts_new_buffer,
1627                        ..
1628                    } => ExpectedBlock::ExcerptHeader {
1629                        height,
1630                        starts_new_buffer,
1631                    },
1632                }
1633            }
1634        }
1635    }
1636
1637    impl TransformBlock {
1638        fn as_custom(&self) -> Option<&Block> {
1639            match self {
1640                TransformBlock::Custom(block) => Some(block),
1641                TransformBlock::ExcerptHeader { .. } => None,
1642            }
1643        }
1644    }
1645
1646    impl BlockSnapshot {
1647        fn to_point(&self, point: BlockPoint, bias: Bias) -> Point {
1648            self.wrap_snapshot.to_point(self.to_wrap_point(point), bias)
1649        }
1650    }
1651}