block_map.rs

   1use super::{
   2    wrap_map::{self, WrapEdit, WrapPoint, WrapSnapshot},
   3    TextHighlights,
   4};
   5use crate::{Anchor, Editor, ExcerptId, ExcerptRange, ToPoint as _};
   6use collections::{Bound, HashMap, HashSet};
   7use gpui::{fonts::HighlightStyle, AnyElement, ViewContext};
   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) -> AnyElement<Editor>>;
  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) -> AnyElement<Editor>>,
  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, 'c> {
  84    pub view_context: &'c mut ViewContext<'a, 'b, 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, 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        suggestion_highlight: Option<HighlightStyle>,
 586    ) -> BlockChunks<'a> {
 587        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 588        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 589        let input_end = {
 590            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 591            let overshoot = if cursor
 592                .item()
 593                .map_or(false, |transform| transform.is_isomorphic())
 594            {
 595                rows.end - cursor.start().0 .0
 596            } else {
 597                0
 598            };
 599            cursor.start().1 .0 + overshoot
 600        };
 601        let input_start = {
 602            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 603            let overshoot = if cursor
 604                .item()
 605                .map_or(false, |transform| transform.is_isomorphic())
 606            {
 607                rows.start - cursor.start().0 .0
 608            } else {
 609                0
 610            };
 611            cursor.start().1 .0 + overshoot
 612        };
 613        BlockChunks {
 614            input_chunks: self.wrap_snapshot.chunks(
 615                input_start..input_end,
 616                language_aware,
 617                text_highlights,
 618                suggestion_highlight,
 619            ),
 620            input_chunk: Default::default(),
 621            transforms: cursor,
 622            output_row: rows.start,
 623            max_output_row,
 624        }
 625    }
 626
 627    pub fn buffer_rows(&self, start_row: u32) -> BlockBufferRows {
 628        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 629        cursor.seek(&BlockRow(start_row), Bias::Right, &());
 630        let (output_start, input_start) = cursor.start();
 631        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 632            start_row - output_start.0
 633        } else {
 634            0
 635        };
 636        let input_start_row = input_start.0 + overshoot;
 637        BlockBufferRows {
 638            transforms: cursor,
 639            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 640            output_row: start_row,
 641            started: false,
 642        }
 643    }
 644
 645    pub fn blocks_in_range(
 646        &self,
 647        rows: Range<u32>,
 648    ) -> impl Iterator<Item = (u32, &TransformBlock)> {
 649        let mut cursor = self.transforms.cursor::<BlockRow>();
 650        cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 651        std::iter::from_fn(move || {
 652            while let Some(transform) = cursor.item() {
 653                let start_row = cursor.start().0;
 654                if start_row >= rows.end {
 655                    break;
 656                }
 657                if let Some(block) = &transform.block {
 658                    cursor.next(&());
 659                    return Some((start_row, block));
 660                } else {
 661                    cursor.next(&());
 662                }
 663            }
 664            None
 665        })
 666    }
 667
 668    pub fn max_point(&self) -> BlockPoint {
 669        let row = self.transforms.summary().output_rows - 1;
 670        BlockPoint::new(row, self.line_len(row))
 671    }
 672
 673    pub fn longest_row(&self) -> u32 {
 674        let input_row = self.wrap_snapshot.longest_row();
 675        self.to_block_point(WrapPoint::new(input_row, 0)).row
 676    }
 677
 678    pub fn line_len(&self, row: u32) -> u32 {
 679        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 680        cursor.seek(&BlockRow(row), Bias::Right, &());
 681        if let Some(transform) = cursor.item() {
 682            let (output_start, input_start) = cursor.start();
 683            let overshoot = row - output_start.0;
 684            if transform.block.is_some() {
 685                0
 686            } else {
 687                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 688            }
 689        } else {
 690            panic!("row out of range");
 691        }
 692    }
 693
 694    pub fn is_block_line(&self, row: u32) -> bool {
 695        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 696        cursor.seek(&BlockRow(row), Bias::Right, &());
 697        cursor.item().map_or(false, |t| t.block.is_some())
 698    }
 699
 700    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 701        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 702        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 703
 704        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 705        let mut search_left =
 706            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 707        let mut reversed = false;
 708
 709        loop {
 710            if let Some(transform) = cursor.item() {
 711                if transform.is_isomorphic() {
 712                    let (output_start_row, input_start_row) = cursor.start();
 713                    let (output_end_row, input_end_row) = cursor.end(&());
 714                    let output_start = Point::new(output_start_row.0, 0);
 715                    let input_start = Point::new(input_start_row.0, 0);
 716                    let input_end = Point::new(input_end_row.0, 0);
 717                    let input_point = if point.row >= output_end_row.0 {
 718                        let line_len = self.wrap_snapshot.line_len(input_end_row.0 - 1);
 719                        self.wrap_snapshot
 720                            .clip_point(WrapPoint::new(input_end_row.0 - 1, line_len), bias)
 721                    } else {
 722                        let output_overshoot = point.0.saturating_sub(output_start);
 723                        self.wrap_snapshot
 724                            .clip_point(WrapPoint(input_start + output_overshoot), bias)
 725                    };
 726
 727                    if (input_start..input_end).contains(&input_point.0) {
 728                        let input_overshoot = input_point.0.saturating_sub(input_start);
 729                        return BlockPoint(output_start + input_overshoot);
 730                    }
 731                }
 732
 733                if search_left {
 734                    cursor.prev(&());
 735                } else {
 736                    cursor.next(&());
 737                }
 738            } else if reversed {
 739                return self.max_point();
 740            } else {
 741                reversed = true;
 742                search_left = !search_left;
 743                cursor.seek(&BlockRow(point.row), Bias::Right, &());
 744            }
 745        }
 746    }
 747
 748    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 749        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 750        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 751        if let Some(transform) = cursor.item() {
 752            debug_assert!(transform.is_isomorphic());
 753        } else {
 754            return self.max_point();
 755        }
 756
 757        let (input_start_row, output_start_row) = cursor.start();
 758        let input_start = Point::new(input_start_row.0, 0);
 759        let output_start = Point::new(output_start_row.0, 0);
 760        let input_overshoot = wrap_point.0 - input_start;
 761        BlockPoint(output_start + input_overshoot)
 762    }
 763
 764    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 765        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 766        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 767        if let Some(transform) = cursor.item() {
 768            match transform.block.as_ref().map(|b| b.disposition()) {
 769                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 770                Some(BlockDisposition::Below) => {
 771                    let wrap_row = cursor.start().1 .0 - 1;
 772                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
 773                }
 774                None => {
 775                    let overshoot = block_point.row - cursor.start().0 .0;
 776                    let wrap_row = cursor.start().1 .0 + overshoot;
 777                    WrapPoint::new(wrap_row, block_point.column)
 778                }
 779            }
 780        } else {
 781            self.wrap_snapshot.max_point()
 782        }
 783    }
 784}
 785
 786impl Transform {
 787    fn isomorphic(rows: u32) -> Self {
 788        Self {
 789            summary: TransformSummary {
 790                input_rows: rows,
 791                output_rows: rows,
 792            },
 793            block: None,
 794        }
 795    }
 796
 797    fn block(block: TransformBlock) -> Self {
 798        Self {
 799            summary: TransformSummary {
 800                input_rows: 0,
 801                output_rows: block.height() as u32,
 802            },
 803            block: Some(block),
 804        }
 805    }
 806
 807    fn is_isomorphic(&self) -> bool {
 808        self.block.is_none()
 809    }
 810}
 811
 812impl<'a> Iterator for BlockChunks<'a> {
 813    type Item = Chunk<'a>;
 814
 815    fn next(&mut self) -> Option<Self::Item> {
 816        if self.output_row >= self.max_output_row {
 817            return None;
 818        }
 819
 820        let transform = self.transforms.item()?;
 821        if transform.block.is_some() {
 822            let block_start = self.transforms.start().0 .0;
 823            let mut block_end = self.transforms.end(&()).0 .0;
 824            self.transforms.next(&());
 825            if self.transforms.item().is_none() {
 826                block_end -= 1;
 827            }
 828
 829            let start_in_block = self.output_row - block_start;
 830            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
 831            let line_count = end_in_block - start_in_block;
 832            self.output_row += line_count;
 833
 834            return Some(Chunk {
 835                text: unsafe { std::str::from_utf8_unchecked(&NEWLINES[..line_count as usize]) },
 836                ..Default::default()
 837            });
 838        }
 839
 840        if self.input_chunk.text.is_empty() {
 841            if let Some(input_chunk) = self.input_chunks.next() {
 842                self.input_chunk = input_chunk;
 843            } else {
 844                self.output_row += 1;
 845                if self.output_row < self.max_output_row {
 846                    self.transforms.next(&());
 847                    return Some(Chunk {
 848                        text: "\n",
 849                        ..Default::default()
 850                    });
 851                } else {
 852                    return None;
 853                }
 854            }
 855        }
 856
 857        let transform_end = self.transforms.end(&()).0 .0;
 858        let (prefix_rows, prefix_bytes) =
 859            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
 860        self.output_row += prefix_rows;
 861        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
 862        self.input_chunk.text = suffix;
 863        if self.output_row == transform_end {
 864            self.transforms.next(&());
 865        }
 866
 867        Some(Chunk {
 868            text: prefix,
 869            ..self.input_chunk
 870        })
 871    }
 872}
 873
 874impl<'a> Iterator for BlockBufferRows<'a> {
 875    type Item = Option<u32>;
 876
 877    fn next(&mut self) -> Option<Self::Item> {
 878        if self.started {
 879            self.output_row += 1;
 880        } else {
 881            self.started = true;
 882        }
 883
 884        if self.output_row >= self.transforms.end(&()).0 .0 {
 885            self.transforms.next(&());
 886        }
 887
 888        let transform = self.transforms.item()?;
 889        if transform.block.is_some() {
 890            Some(None)
 891        } else {
 892            Some(self.input_buffer_rows.next().unwrap())
 893        }
 894    }
 895}
 896
 897impl sum_tree::Item for Transform {
 898    type Summary = TransformSummary;
 899
 900    fn summary(&self) -> Self::Summary {
 901        self.summary.clone()
 902    }
 903}
 904
 905impl sum_tree::Summary for TransformSummary {
 906    type Context = ();
 907
 908    fn add_summary(&mut self, summary: &Self, _: &()) {
 909        self.input_rows += summary.input_rows;
 910        self.output_rows += summary.output_rows;
 911    }
 912}
 913
 914impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
 915    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 916        self.0 += summary.input_rows;
 917    }
 918}
 919
 920impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
 921    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 922        self.0 += summary.output_rows;
 923    }
 924}
 925
 926impl BlockDisposition {
 927    fn is_below(&self) -> bool {
 928        matches!(self, BlockDisposition::Below)
 929    }
 930}
 931
 932impl<'a, 'b, 'c> Deref for BlockContext<'a, 'b, 'c> {
 933    type Target = ViewContext<'a, 'b, Editor>;
 934
 935    fn deref(&self) -> &Self::Target {
 936        self.view_context
 937    }
 938}
 939
 940impl DerefMut for BlockContext<'_, '_, '_> {
 941    fn deref_mut(&mut self) -> &mut Self::Target {
 942        self.view_context
 943    }
 944}
 945
 946impl Block {
 947    pub fn render(&self, cx: &mut BlockContext) -> AnyElement<Editor> {
 948        self.render.lock()(cx)
 949    }
 950
 951    pub fn position(&self) -> &Anchor {
 952        &self.position
 953    }
 954
 955    pub fn style(&self) -> BlockStyle {
 956        self.style
 957    }
 958}
 959
 960impl Debug for Block {
 961    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 962        f.debug_struct("Block")
 963            .field("id", &self.id)
 964            .field("position", &self.position)
 965            .field("disposition", &self.disposition)
 966            .finish()
 967    }
 968}
 969
 970// Count the number of bytes prior to a target point. If the string doesn't contain the target
 971// point, return its total extent. Otherwise return the target point itself.
 972fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 973    let mut row = 0;
 974    let mut offset = 0;
 975    for (ix, line) in s.split('\n').enumerate() {
 976        if ix > 0 {
 977            row += 1;
 978            offset += 1;
 979        }
 980        if row >= target {
 981            break;
 982        }
 983        offset += line.len() as usize;
 984    }
 985    (row, offset)
 986}
 987
 988#[cfg(test)]
 989mod tests {
 990    use super::*;
 991    use crate::display_map::suggestion_map::SuggestionMap;
 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::SettingsStore;
 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::AppContext) {
1016        init_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, fold_snapshot) = FoldMap::new(buffer_snapshot.clone());
1033        let (suggestion_map, suggestion_snapshot) = SuggestionMap::new(fold_snapshot);
1034        let (tab_map, tab_snapshot) = TabMap::new(suggestion_snapshot, 1.try_into().unwrap());
1035        let (wrap_map, wraps_snapshot) = WrapMap::new(tab_snapshot, font_id, 14.0, None, cx);
1036        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1, 1);
1037
1038        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1039        let block_ids = writer.insert(vec![
1040            BlockProperties {
1041                style: BlockStyle::Fixed,
1042                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
1043                height: 1,
1044                disposition: BlockDisposition::Above,
1045                render: Arc::new(|_| Empty::new().into_any_named("block 1")),
1046            },
1047            BlockProperties {
1048                style: BlockStyle::Fixed,
1049                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
1050                height: 2,
1051                disposition: BlockDisposition::Above,
1052                render: Arc::new(|_| Empty::new().into_any_named("block 2")),
1053            },
1054            BlockProperties {
1055                style: BlockStyle::Fixed,
1056                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
1057                height: 3,
1058                disposition: BlockDisposition::Below,
1059                render: Arc::new(|_| Empty::new().into_any_named("block 3")),
1060            },
1061        ]);
1062
1063        let snapshot = block_map.read(wraps_snapshot, Default::default());
1064        assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
1065
1066        let blocks = snapshot
1067            .blocks_in_range(0..8)
1068            .map(|(start_row, block)| {
1069                let block = block.as_custom().unwrap();
1070                (start_row..start_row + block.height as u32, block.id)
1071            })
1072            .collect::<Vec<_>>();
1073
1074        // When multiple blocks are on the same line, the newer blocks appear first.
1075        assert_eq!(
1076            blocks,
1077            &[
1078                (1..2, block_ids[0]),
1079                (2..4, block_ids[1]),
1080                (7..10, block_ids[2]),
1081            ]
1082        );
1083
1084        assert_eq!(
1085            snapshot.to_block_point(WrapPoint::new(0, 3)),
1086            BlockPoint::new(0, 3)
1087        );
1088        assert_eq!(
1089            snapshot.to_block_point(WrapPoint::new(1, 0)),
1090            BlockPoint::new(4, 0)
1091        );
1092        assert_eq!(
1093            snapshot.to_block_point(WrapPoint::new(3, 3)),
1094            BlockPoint::new(6, 3)
1095        );
1096
1097        assert_eq!(
1098            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
1099            WrapPoint::new(0, 3)
1100        );
1101        assert_eq!(
1102            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
1103            WrapPoint::new(1, 0)
1104        );
1105        assert_eq!(
1106            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
1107            WrapPoint::new(1, 0)
1108        );
1109        assert_eq!(
1110            snapshot.to_wrap_point(BlockPoint::new(7, 0)),
1111            WrapPoint::new(3, 3)
1112        );
1113
1114        assert_eq!(
1115            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
1116            BlockPoint::new(0, 3)
1117        );
1118        assert_eq!(
1119            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
1120            BlockPoint::new(4, 0)
1121        );
1122        assert_eq!(
1123            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1124            BlockPoint::new(0, 3)
1125        );
1126        assert_eq!(
1127            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1128            BlockPoint::new(4, 0)
1129        );
1130        assert_eq!(
1131            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Left),
1132            BlockPoint::new(4, 0)
1133        );
1134        assert_eq!(
1135            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Right),
1136            BlockPoint::new(4, 0)
1137        );
1138        assert_eq!(
1139            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Left),
1140            BlockPoint::new(6, 3)
1141        );
1142        assert_eq!(
1143            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Right),
1144            BlockPoint::new(6, 3)
1145        );
1146        assert_eq!(
1147            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Left),
1148            BlockPoint::new(6, 3)
1149        );
1150        assert_eq!(
1151            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Right),
1152            BlockPoint::new(6, 3)
1153        );
1154
1155        assert_eq!(
1156            snapshot.buffer_rows(0).collect::<Vec<_>>(),
1157            &[
1158                Some(0),
1159                None,
1160                None,
1161                None,
1162                Some(1),
1163                Some(2),
1164                Some(3),
1165                None,
1166                None,
1167                None
1168            ]
1169        );
1170
1171        // Insert a line break, separating two block decorations into separate lines.
1172        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1173            buffer.edit([(Point::new(1, 1)..Point::new(1, 1), "!!!\n")], None, cx);
1174            buffer.snapshot(cx)
1175        });
1176
1177        let (fold_snapshot, fold_edits) =
1178            fold_map.read(buffer_snapshot, subscription.consume().into_inner());
1179        let (suggestion_snapshot, suggestion_edits) =
1180            suggestion_map.sync(fold_snapshot, fold_edits);
1181        let (tab_snapshot, tab_edits) =
1182            tab_map.sync(suggestion_snapshot, suggestion_edits, 4.try_into().unwrap());
1183        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1184            wrap_map.sync(tab_snapshot, tab_edits, cx)
1185        });
1186        let snapshot = block_map.read(wraps_snapshot, wrap_edits);
1187        assert_eq!(snapshot.text(), "aaa\n\nb!!!\n\n\nbb\nccc\nddd\n\n\n");
1188    }
1189
1190    #[gpui::test]
1191    fn test_blocks_on_wrapped_lines(cx: &mut gpui::AppContext) {
1192        init_test(cx);
1193
1194        let family_id = cx
1195            .font_cache()
1196            .load_family(&["Helvetica"], &Default::default())
1197            .unwrap();
1198        let font_id = cx
1199            .font_cache()
1200            .select_font(family_id, &Default::default())
1201            .unwrap();
1202
1203        let text = "one two three\nfour five six\nseven eight";
1204
1205        let buffer = MultiBuffer::build_simple(text, cx);
1206        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1207        let (_, fold_snapshot) = FoldMap::new(buffer_snapshot.clone());
1208        let (_, suggestion_snapshot) = SuggestionMap::new(fold_snapshot);
1209        let (_, tab_snapshot) = TabMap::new(suggestion_snapshot, 1.try_into().unwrap());
1210        let (_, wraps_snapshot) = WrapMap::new(tab_snapshot, font_id, 14.0, Some(60.), cx);
1211        let mut block_map = BlockMap::new(wraps_snapshot.clone(), 1, 1);
1212
1213        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1214        writer.insert(vec![
1215            BlockProperties {
1216                style: BlockStyle::Fixed,
1217                position: buffer_snapshot.anchor_after(Point::new(1, 12)),
1218                disposition: BlockDisposition::Above,
1219                render: Arc::new(|_| Empty::new().into_any_named("block 1")),
1220                height: 1,
1221            },
1222            BlockProperties {
1223                style: BlockStyle::Fixed,
1224                position: buffer_snapshot.anchor_after(Point::new(1, 1)),
1225                disposition: BlockDisposition::Below,
1226                render: Arc::new(|_| Empty::new().into_any_named("block 2")),
1227                height: 1,
1228            },
1229        ]);
1230
1231        // Blocks with an 'above' disposition go above their corresponding buffer line.
1232        // Blocks with a 'below' disposition go below their corresponding buffer line.
1233        let snapshot = block_map.read(wraps_snapshot, Default::default());
1234        assert_eq!(
1235            snapshot.text(),
1236            "one two \nthree\n\nfour five \nsix\n\nseven \neight"
1237        );
1238    }
1239
1240    #[gpui::test(iterations = 100)]
1241    fn test_random_blocks(cx: &mut gpui::AppContext, mut rng: StdRng) {
1242        init_test(cx);
1243
1244        let operations = env::var("OPERATIONS")
1245            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1246            .unwrap_or(10);
1247
1248        let wrap_width = if rng.gen_bool(0.2) {
1249            None
1250        } else {
1251            Some(rng.gen_range(0.0..=100.0))
1252        };
1253        let tab_size = 1.try_into().unwrap();
1254        let family_id = cx
1255            .font_cache()
1256            .load_family(&["Helvetica"], &Default::default())
1257            .unwrap();
1258        let font_id = cx
1259            .font_cache()
1260            .select_font(family_id, &Default::default())
1261            .unwrap();
1262        let font_size = 14.0;
1263        let buffer_start_header_height = rng.gen_range(1..=5);
1264        let excerpt_header_height = rng.gen_range(1..=5);
1265
1266        log::info!("Wrap width: {:?}", wrap_width);
1267        log::info!("Excerpt Header Height: {:?}", excerpt_header_height);
1268
1269        let buffer = if rng.gen() {
1270            let len = rng.gen_range(0..10);
1271            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1272            log::info!("initial buffer text: {:?}", text);
1273            MultiBuffer::build_simple(&text, cx)
1274        } else {
1275            MultiBuffer::build_random(&mut rng, cx)
1276        };
1277
1278        let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
1279        let (fold_map, fold_snapshot) = FoldMap::new(buffer_snapshot.clone());
1280        let (suggestion_map, suggestion_snapshot) = SuggestionMap::new(fold_snapshot);
1281        let (tab_map, tab_snapshot) = TabMap::new(suggestion_snapshot, tab_size);
1282        let (wrap_map, wraps_snapshot) =
1283            WrapMap::new(tab_snapshot, font_id, font_size, wrap_width, cx);
1284        let mut block_map = BlockMap::new(
1285            wraps_snapshot,
1286            buffer_start_header_height,
1287            excerpt_header_height,
1288        );
1289        let mut custom_blocks = Vec::new();
1290
1291        for _ in 0..operations {
1292            let mut buffer_edits = Vec::new();
1293            match rng.gen_range(0..=100) {
1294                0..=19 => {
1295                    let wrap_width = if rng.gen_bool(0.2) {
1296                        None
1297                    } else {
1298                        Some(rng.gen_range(0.0..=100.0))
1299                    };
1300                    log::info!("Setting wrap width to {:?}", wrap_width);
1301                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1302                }
1303                20..=39 => {
1304                    let block_count = rng.gen_range(1..=5);
1305                    let block_properties = (0..block_count)
1306                        .map(|_| {
1307                            let buffer = buffer.read(cx).read(cx);
1308                            let position = buffer.anchor_after(
1309                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1310                            );
1311
1312                            let disposition = if rng.gen() {
1313                                BlockDisposition::Above
1314                            } else {
1315                                BlockDisposition::Below
1316                            };
1317                            let height = rng.gen_range(1..5);
1318                            log::info!(
1319                                "inserting block {:?} {:?} with height {}",
1320                                disposition,
1321                                position.to_point(&buffer),
1322                                height
1323                            );
1324                            BlockProperties {
1325                                style: BlockStyle::Fixed,
1326                                position,
1327                                height,
1328                                disposition,
1329                                render: Arc::new(|_| Empty::new().into_any()),
1330                            }
1331                        })
1332                        .collect::<Vec<_>>();
1333
1334                    let (fold_snapshot, fold_edits) =
1335                        fold_map.read(buffer_snapshot.clone(), vec![]);
1336                    let (suggestion_snapshot, suggestion_edits) =
1337                        suggestion_map.sync(fold_snapshot, fold_edits);
1338                    let (tab_snapshot, tab_edits) =
1339                        tab_map.sync(suggestion_snapshot, suggestion_edits, tab_size);
1340                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1341                        wrap_map.sync(tab_snapshot, tab_edits, cx)
1342                    });
1343                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1344                    let block_ids = block_map.insert(block_properties.clone());
1345                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1346                        custom_blocks.push((block_id, props));
1347                    }
1348                }
1349                40..=59 if !custom_blocks.is_empty() => {
1350                    let block_count = rng.gen_range(1..=4.min(custom_blocks.len()));
1351                    let block_ids_to_remove = (0..block_count)
1352                        .map(|_| {
1353                            custom_blocks
1354                                .remove(rng.gen_range(0..custom_blocks.len()))
1355                                .0
1356                        })
1357                        .collect();
1358
1359                    let (fold_snapshot, fold_edits) =
1360                        fold_map.read(buffer_snapshot.clone(), vec![]);
1361                    let (suggestion_snapshot, suggestion_edits) =
1362                        suggestion_map.sync(fold_snapshot, fold_edits);
1363                    let (tab_snapshot, tab_edits) =
1364                        tab_map.sync(suggestion_snapshot, suggestion_edits, tab_size);
1365                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1366                        wrap_map.sync(tab_snapshot, tab_edits, cx)
1367                    });
1368                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1369                    block_map.remove(block_ids_to_remove);
1370                }
1371                _ => {
1372                    buffer.update(cx, |buffer, cx| {
1373                        let mutation_count = rng.gen_range(1..=5);
1374                        let subscription = buffer.subscribe();
1375                        buffer.randomly_mutate(&mut rng, mutation_count, cx);
1376                        buffer_snapshot = buffer.snapshot(cx);
1377                        buffer_edits.extend(subscription.consume());
1378                        log::info!("buffer text: {:?}", buffer_snapshot.text());
1379                    });
1380                }
1381            }
1382
1383            let (fold_snapshot, fold_edits) = fold_map.read(buffer_snapshot.clone(), buffer_edits);
1384            let (suggestion_snapshot, suggestion_edits) =
1385                suggestion_map.sync(fold_snapshot, fold_edits);
1386            let (tab_snapshot, tab_edits) =
1387                tab_map.sync(suggestion_snapshot, suggestion_edits, tab_size);
1388            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1389                wrap_map.sync(tab_snapshot, tab_edits, cx)
1390            });
1391            let blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits);
1392            assert_eq!(
1393                blocks_snapshot.transforms.summary().input_rows,
1394                wraps_snapshot.max_point().row() + 1
1395            );
1396            log::info!("blocks text: {:?}", blocks_snapshot.text());
1397
1398            let mut expected_blocks = Vec::new();
1399            expected_blocks.extend(custom_blocks.iter().map(|(id, block)| {
1400                let mut position = block.position.to_point(&buffer_snapshot);
1401                match block.disposition {
1402                    BlockDisposition::Above => {
1403                        position.column = 0;
1404                    }
1405                    BlockDisposition::Below => {
1406                        position.column = buffer_snapshot.line_len(position.row);
1407                    }
1408                };
1409                let row = wraps_snapshot.make_wrap_point(position, Bias::Left).row();
1410                (
1411                    row,
1412                    ExpectedBlock::Custom {
1413                        disposition: block.disposition,
1414                        id: *id,
1415                        height: block.height,
1416                    },
1417                )
1418            }));
1419            expected_blocks.extend(buffer_snapshot.excerpt_boundaries_in_range(0..).map(
1420                |boundary| {
1421                    let position =
1422                        wraps_snapshot.make_wrap_point(Point::new(boundary.row, 0), Bias::Left);
1423                    (
1424                        position.row(),
1425                        ExpectedBlock::ExcerptHeader {
1426                            height: if boundary.starts_new_buffer {
1427                                buffer_start_header_height
1428                            } else {
1429                                excerpt_header_height
1430                            },
1431                            starts_new_buffer: boundary.starts_new_buffer,
1432                        },
1433                    )
1434                },
1435            ));
1436            expected_blocks.sort_unstable();
1437            let mut sorted_blocks_iter = expected_blocks.into_iter().peekable();
1438
1439            let input_buffer_rows = buffer_snapshot.buffer_rows(0).collect::<Vec<_>>();
1440            let mut expected_buffer_rows = Vec::new();
1441            let mut expected_text = String::new();
1442            let mut expected_block_positions = Vec::new();
1443            let input_text = wraps_snapshot.text();
1444            for (row, input_line) in input_text.split('\n').enumerate() {
1445                let row = row as u32;
1446                if row > 0 {
1447                    expected_text.push('\n');
1448                }
1449
1450                let buffer_row = input_buffer_rows[wraps_snapshot
1451                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1452                    .row as usize];
1453
1454                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1455                    if *block_row == row && block.disposition() == BlockDisposition::Above {
1456                        let (_, block) = sorted_blocks_iter.next().unwrap();
1457                        let height = block.height() as usize;
1458                        expected_block_positions
1459                            .push((expected_text.matches('\n').count() as u32, block));
1460                        let text = "\n".repeat(height);
1461                        expected_text.push_str(&text);
1462                        for _ in 0..height {
1463                            expected_buffer_rows.push(None);
1464                        }
1465                    } else {
1466                        break;
1467                    }
1468                }
1469
1470                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1471                expected_buffer_rows.push(if soft_wrapped { None } else { buffer_row });
1472                expected_text.push_str(input_line);
1473
1474                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1475                    if *block_row == row && block.disposition() == BlockDisposition::Below {
1476                        let (_, block) = sorted_blocks_iter.next().unwrap();
1477                        let height = block.height() as usize;
1478                        expected_block_positions
1479                            .push((expected_text.matches('\n').count() as u32 + 1, block));
1480                        let text = "\n".repeat(height);
1481                        expected_text.push_str(&text);
1482                        for _ in 0..height {
1483                            expected_buffer_rows.push(None);
1484                        }
1485                    } else {
1486                        break;
1487                    }
1488                }
1489            }
1490
1491            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1492            let expected_row_count = expected_lines.len();
1493            for start_row in 0..expected_row_count {
1494                let expected_text = expected_lines[start_row..].join("\n");
1495                let actual_text = blocks_snapshot
1496                    .chunks(
1497                        start_row as u32..blocks_snapshot.max_point().row + 1,
1498                        false,
1499                        None,
1500                        None,
1501                    )
1502                    .map(|chunk| chunk.text)
1503                    .collect::<String>();
1504                assert_eq!(
1505                    actual_text, expected_text,
1506                    "incorrect text starting from row {}",
1507                    start_row
1508                );
1509                assert_eq!(
1510                    blocks_snapshot
1511                        .buffer_rows(start_row as u32)
1512                        .collect::<Vec<_>>(),
1513                    &expected_buffer_rows[start_row..]
1514                );
1515            }
1516
1517            assert_eq!(
1518                blocks_snapshot
1519                    .blocks_in_range(0..(expected_row_count as u32))
1520                    .map(|(row, block)| (row, block.clone().into()))
1521                    .collect::<Vec<_>>(),
1522                expected_block_positions
1523            );
1524
1525            let mut expected_longest_rows = Vec::new();
1526            let mut longest_line_len = -1_isize;
1527            for (row, line) in expected_lines.iter().enumerate() {
1528                let row = row as u32;
1529
1530                assert_eq!(
1531                    blocks_snapshot.line_len(row),
1532                    line.len() as u32,
1533                    "invalid line len for row {}",
1534                    row
1535                );
1536
1537                let line_char_count = line.chars().count() as isize;
1538                match line_char_count.cmp(&longest_line_len) {
1539                    Ordering::Less => {}
1540                    Ordering::Equal => expected_longest_rows.push(row),
1541                    Ordering::Greater => {
1542                        longest_line_len = line_char_count;
1543                        expected_longest_rows.clear();
1544                        expected_longest_rows.push(row);
1545                    }
1546                }
1547            }
1548
1549            let longest_row = blocks_snapshot.longest_row();
1550            assert!(
1551                expected_longest_rows.contains(&longest_row),
1552                "incorrect longest row {}. expected {:?} with length {}",
1553                longest_row,
1554                expected_longest_rows,
1555                longest_line_len,
1556            );
1557
1558            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1559                let wrap_point = WrapPoint::new(row, 0);
1560                let block_point = blocks_snapshot.to_block_point(wrap_point);
1561                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1562            }
1563
1564            let mut block_point = BlockPoint::new(0, 0);
1565            for c in expected_text.chars() {
1566                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1567                let left_buffer_point = blocks_snapshot.to_point(left_point, Bias::Left);
1568                assert_eq!(
1569                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1570                    left_point
1571                );
1572                assert_eq!(
1573                    left_buffer_point,
1574                    buffer_snapshot.clip_point(left_buffer_point, Bias::Right),
1575                    "{:?} is not valid in buffer coordinates",
1576                    left_point
1577                );
1578
1579                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1580                let right_buffer_point = blocks_snapshot.to_point(right_point, Bias::Right);
1581                assert_eq!(
1582                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1583                    right_point
1584                );
1585                assert_eq!(
1586                    right_buffer_point,
1587                    buffer_snapshot.clip_point(right_buffer_point, Bias::Left),
1588                    "{:?} is not valid in buffer coordinates",
1589                    right_point
1590                );
1591
1592                if c == '\n' {
1593                    block_point.0 += Point::new(1, 0);
1594                } else {
1595                    block_point.column += c.len_utf8() as u32;
1596                }
1597            }
1598        }
1599
1600        #[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
1601        enum ExpectedBlock {
1602            ExcerptHeader {
1603                height: u8,
1604                starts_new_buffer: bool,
1605            },
1606            Custom {
1607                disposition: BlockDisposition,
1608                id: BlockId,
1609                height: u8,
1610            },
1611        }
1612
1613        impl ExpectedBlock {
1614            fn height(&self) -> u8 {
1615                match self {
1616                    ExpectedBlock::ExcerptHeader { height, .. } => *height,
1617                    ExpectedBlock::Custom { height, .. } => *height,
1618                }
1619            }
1620
1621            fn disposition(&self) -> BlockDisposition {
1622                match self {
1623                    ExpectedBlock::ExcerptHeader { .. } => BlockDisposition::Above,
1624                    ExpectedBlock::Custom { disposition, .. } => *disposition,
1625                }
1626            }
1627        }
1628
1629        impl From<TransformBlock> for ExpectedBlock {
1630            fn from(block: TransformBlock) -> Self {
1631                match block {
1632                    TransformBlock::Custom(block) => ExpectedBlock::Custom {
1633                        id: block.id,
1634                        disposition: block.disposition,
1635                        height: block.height,
1636                    },
1637                    TransformBlock::ExcerptHeader {
1638                        height,
1639                        starts_new_buffer,
1640                        ..
1641                    } => ExpectedBlock::ExcerptHeader {
1642                        height,
1643                        starts_new_buffer,
1644                    },
1645                }
1646            }
1647        }
1648    }
1649
1650    fn init_test(cx: &mut gpui::AppContext) {
1651        cx.set_global(SettingsStore::test(cx));
1652        theme::init((), cx);
1653    }
1654
1655    impl TransformBlock {
1656        fn as_custom(&self) -> Option<&Block> {
1657            match self {
1658                TransformBlock::Custom(block) => Some(block),
1659                TransformBlock::ExcerptHeader { .. } => None,
1660            }
1661        }
1662    }
1663
1664    impl BlockSnapshot {
1665        fn to_point(&self, point: BlockPoint, bias: Bias) -> Point {
1666            self.wrap_snapshot.to_point(self.to_wrap_point(point), bias)
1667        }
1668    }
1669}