1use super::{
   2    wrap_map::{self, WrapEdit, WrapPoint, WrapSnapshot},
   3    Highlights,
   4};
   5use crate::{EditorStyle, GutterDimensions};
   6use collections::{Bound, HashMap, HashSet};
   7use gpui::{AnyElement, Pixels, WindowContext};
   8use language::{BufferSnapshot, Chunk, Patch, Point};
   9use multi_buffer::{Anchor, ExcerptId, ExcerptRange, MultiBufferRow, ToPoint as _};
  10use parking_lot::Mutex;
  11use std::{
  12    cell::RefCell,
  13    cmp::{self, Ordering},
  14    fmt::Debug,
  15    ops::{Deref, DerefMut, Range, RangeBounds},
  16    sync::{
  17        atomic::{AtomicUsize, Ordering::SeqCst},
  18        Arc,
  19    },
  20};
  21use sum_tree::{Bias, SumTree};
  22use text::Edit;
  23
  24const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  25
  26/// Tracks custom blocks such as diagnostics that should be displayed within buffer.
  27///
  28/// See the [`display_map` module documentation](crate::display_map) for more information.
  29pub struct BlockMap {
  30    next_block_id: AtomicUsize,
  31    wrap_snapshot: RefCell<WrapSnapshot>,
  32    blocks: Vec<Arc<Block>>,
  33    transforms: RefCell<SumTree<Transform>>,
  34    show_excerpt_controls: bool,
  35    buffer_header_height: u8,
  36    excerpt_header_height: u8,
  37    excerpt_footer_height: u8,
  38}
  39
  40pub struct BlockMapReader<'a> {
  41    blocks: &'a Vec<Arc<Block>>,
  42    pub snapshot: BlockSnapshot,
  43}
  44
  45pub struct BlockMapWriter<'a>(&'a mut BlockMap);
  46
  47#[derive(Clone)]
  48pub struct BlockSnapshot {
  49    wrap_snapshot: WrapSnapshot,
  50    transforms: SumTree<Transform>,
  51}
  52
  53#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
  54pub struct BlockId(usize);
  55
  56#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  57pub struct BlockPoint(pub Point);
  58
  59#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  60pub struct BlockRow(pub(super) u32);
  61
  62#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  63struct WrapRow(u32);
  64
  65pub type RenderBlock = Box<dyn Send + Fn(&mut BlockContext) -> AnyElement>;
  66
  67pub struct Block {
  68    id: BlockId,
  69    position: Anchor,
  70    height: u8,
  71    style: BlockStyle,
  72    render: Mutex<RenderBlock>,
  73    disposition: BlockDisposition,
  74}
  75
  76pub struct BlockProperties<P> {
  77    pub position: P,
  78    pub height: u8,
  79    pub style: BlockStyle,
  80    pub render: Box<dyn Send + Fn(&mut BlockContext) -> AnyElement>,
  81    pub disposition: BlockDisposition,
  82}
  83
  84#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
  85pub enum BlockStyle {
  86    Fixed,
  87    Flex,
  88    Sticky,
  89}
  90
  91pub struct BlockContext<'a, 'b> {
  92    pub context: &'b mut WindowContext<'a>,
  93    pub anchor_x: Pixels,
  94    pub max_width: Pixels,
  95    pub gutter_dimensions: &'b GutterDimensions,
  96    pub em_width: Pixels,
  97    pub line_height: Pixels,
  98    pub block_id: usize,
  99    pub editor_style: &'b EditorStyle,
 100}
 101
 102/// Whether the block should be considered above or below the anchor line
 103#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 104pub enum BlockDisposition {
 105    Above,
 106    Below,
 107}
 108
 109#[derive(Clone, Debug)]
 110struct Transform {
 111    summary: TransformSummary,
 112    block: Option<TransformBlock>,
 113}
 114
 115pub(crate) enum BlockType {
 116    Custom(BlockId),
 117    Header,
 118    Footer,
 119}
 120
 121pub(crate) trait BlockLike {
 122    fn block_type(&self) -> BlockType;
 123    fn disposition(&self) -> BlockDisposition;
 124}
 125
 126#[allow(clippy::large_enum_variant)]
 127#[derive(Clone)]
 128pub enum TransformBlock {
 129    Custom(Arc<Block>),
 130    ExcerptHeader {
 131        id: ExcerptId,
 132        buffer: BufferSnapshot,
 133        range: ExcerptRange<text::Anchor>,
 134        height: u8,
 135        starts_new_buffer: bool,
 136        show_excerpt_controls: bool,
 137    },
 138    ExcerptFooter {
 139        id: ExcerptId,
 140        disposition: BlockDisposition,
 141        height: u8,
 142    },
 143}
 144
 145impl BlockLike for TransformBlock {
 146    fn block_type(&self) -> BlockType {
 147        match self {
 148            TransformBlock::Custom(block) => BlockType::Custom(block.id),
 149            TransformBlock::ExcerptHeader { .. } => BlockType::Header,
 150            TransformBlock::ExcerptFooter { .. } => BlockType::Footer,
 151        }
 152    }
 153
 154    fn disposition(&self) -> BlockDisposition {
 155        self.disposition()
 156    }
 157}
 158
 159impl TransformBlock {
 160    fn disposition(&self) -> BlockDisposition {
 161        match self {
 162            TransformBlock::Custom(block) => block.disposition,
 163            TransformBlock::ExcerptHeader { .. } => BlockDisposition::Above,
 164            TransformBlock::ExcerptFooter { disposition, .. } => *disposition,
 165        }
 166    }
 167
 168    pub fn height(&self) -> u8 {
 169        match self {
 170            TransformBlock::Custom(block) => block.height,
 171            TransformBlock::ExcerptHeader { height, .. } => *height,
 172            TransformBlock::ExcerptFooter { height, .. } => *height,
 173        }
 174    }
 175}
 176
 177impl Debug for TransformBlock {
 178    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 179        match self {
 180            Self::Custom(block) => f.debug_struct("Custom").field("block", block).finish(),
 181            Self::ExcerptHeader {
 182                buffer,
 183                starts_new_buffer,
 184                id,
 185                ..
 186            } => f
 187                .debug_struct("ExcerptHeader")
 188                .field("id", &id)
 189                .field("path", &buffer.file().map(|f| f.path()))
 190                .field("starts_new_buffer", &starts_new_buffer)
 191                .finish(),
 192            TransformBlock::ExcerptFooter {
 193                id, disposition, ..
 194            } => f
 195                .debug_struct("ExcerptFooter")
 196                .field("id", &id)
 197                .field("disposition", &disposition)
 198                .finish(),
 199        }
 200    }
 201}
 202
 203#[derive(Clone, Debug, Default)]
 204struct TransformSummary {
 205    input_rows: u32,
 206    output_rows: u32,
 207}
 208
 209pub struct BlockChunks<'a> {
 210    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 211    input_chunks: wrap_map::WrapChunks<'a>,
 212    input_chunk: Chunk<'a>,
 213    output_row: u32,
 214    max_output_row: u32,
 215}
 216
 217#[derive(Clone)]
 218pub struct BlockBufferRows<'a> {
 219    transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
 220    input_buffer_rows: wrap_map::WrapBufferRows<'a>,
 221    output_row: BlockRow,
 222    started: bool,
 223}
 224
 225impl BlockMap {
 226    pub fn new(
 227        wrap_snapshot: WrapSnapshot,
 228        show_excerpt_controls: bool,
 229        buffer_header_height: u8,
 230        excerpt_header_height: u8,
 231        excerpt_footer_height: u8,
 232    ) -> Self {
 233        let row_count = wrap_snapshot.max_point().row() + 1;
 234        let map = Self {
 235            next_block_id: AtomicUsize::new(0),
 236            blocks: Vec::new(),
 237            transforms: RefCell::new(SumTree::from_item(Transform::isomorphic(row_count), &())),
 238            wrap_snapshot: RefCell::new(wrap_snapshot.clone()),
 239            show_excerpt_controls,
 240            buffer_header_height,
 241            excerpt_header_height,
 242            excerpt_footer_height,
 243        };
 244        map.sync(
 245            &wrap_snapshot,
 246            Patch::new(vec![Edit {
 247                old: 0..row_count,
 248                new: 0..row_count,
 249            }]),
 250        );
 251        map
 252    }
 253
 254    pub fn read(&self, wrap_snapshot: WrapSnapshot, edits: Patch<u32>) -> BlockMapReader {
 255        self.sync(&wrap_snapshot, edits);
 256        *self.wrap_snapshot.borrow_mut() = wrap_snapshot.clone();
 257        BlockMapReader {
 258            blocks: &self.blocks,
 259            snapshot: BlockSnapshot {
 260                wrap_snapshot,
 261                transforms: self.transforms.borrow().clone(),
 262            },
 263        }
 264    }
 265
 266    pub fn write(&mut self, wrap_snapshot: WrapSnapshot, edits: Patch<u32>) -> BlockMapWriter {
 267        self.sync(&wrap_snapshot, edits);
 268        *self.wrap_snapshot.borrow_mut() = wrap_snapshot;
 269        BlockMapWriter(self)
 270    }
 271
 272    fn sync(&self, wrap_snapshot: &WrapSnapshot, mut edits: Patch<u32>) {
 273        let buffer = wrap_snapshot.buffer_snapshot();
 274
 275        // Handle changing the last excerpt if it is empty.
 276        if buffer.trailing_excerpt_update_count()
 277            != self
 278                .wrap_snapshot
 279                .borrow()
 280                .buffer_snapshot()
 281                .trailing_excerpt_update_count()
 282        {
 283            let max_point = wrap_snapshot.max_point();
 284            let edit_start = wrap_snapshot.prev_row_boundary(max_point);
 285            let edit_end = max_point.row() + 1;
 286            edits = edits.compose([WrapEdit {
 287                old: edit_start..edit_end,
 288                new: edit_start..edit_end,
 289            }]);
 290        }
 291
 292        let edits = edits.into_inner();
 293        if edits.is_empty() {
 294            return;
 295        }
 296
 297        let mut transforms = self.transforms.borrow_mut();
 298        let mut new_transforms = SumTree::new();
 299        let old_row_count = transforms.summary().input_rows;
 300        let new_row_count = wrap_snapshot.max_point().row() + 1;
 301        let mut cursor = transforms.cursor::<WrapRow>();
 302        let mut last_block_ix = 0;
 303        let mut blocks_in_edit = Vec::new();
 304        let mut edits = edits.into_iter().peekable();
 305
 306        while let Some(edit) = edits.next() {
 307            // Preserve any old transforms that precede this edit.
 308            let old_start = WrapRow(edit.old.start);
 309            let new_start = WrapRow(edit.new.start);
 310            new_transforms.append(cursor.slice(&old_start, Bias::Left, &()), &());
 311            if let Some(transform) = cursor.item() {
 312                if transform.is_isomorphic() && old_start == cursor.end(&()) {
 313                    new_transforms.push(transform.clone(), &());
 314                    cursor.next(&());
 315                    while let Some(transform) = cursor.item() {
 316                        if transform
 317                            .block
 318                            .as_ref()
 319                            .map_or(false, |b| b.disposition().is_below())
 320                        {
 321                            new_transforms.push(transform.clone(), &());
 322                            cursor.next(&());
 323                        } else {
 324                            break;
 325                        }
 326                    }
 327                }
 328            }
 329
 330            // Preserve any portion of an old transform that precedes this edit.
 331            let extent_before_edit = old_start.0 - cursor.start().0;
 332            push_isomorphic(&mut new_transforms, extent_before_edit);
 333
 334            // Skip over any old transforms that intersect this edit.
 335            let mut old_end = WrapRow(edit.old.end);
 336            let mut new_end = WrapRow(edit.new.end);
 337            cursor.seek(&old_end, Bias::Left, &());
 338            cursor.next(&());
 339            if old_end == *cursor.start() {
 340                while let Some(transform) = cursor.item() {
 341                    if transform
 342                        .block
 343                        .as_ref()
 344                        .map_or(false, |b| b.disposition().is_below())
 345                    {
 346                        cursor.next(&());
 347                    } else {
 348                        break;
 349                    }
 350                }
 351            }
 352
 353            // Combine this edit with any subsequent edits that intersect the same transform.
 354            while let Some(next_edit) = edits.peek() {
 355                if next_edit.old.start <= cursor.start().0 {
 356                    old_end = WrapRow(next_edit.old.end);
 357                    new_end = WrapRow(next_edit.new.end);
 358                    cursor.seek(&old_end, Bias::Left, &());
 359                    cursor.next(&());
 360                    if old_end == *cursor.start() {
 361                        while let Some(transform) = cursor.item() {
 362                            if transform
 363                                .block
 364                                .as_ref()
 365                                .map_or(false, |b| b.disposition().is_below())
 366                            {
 367                                cursor.next(&());
 368                            } else {
 369                                break;
 370                            }
 371                        }
 372                    }
 373                    edits.next();
 374                } else {
 375                    break;
 376                }
 377            }
 378
 379            // Find the blocks within this edited region.
 380            let new_buffer_start =
 381                wrap_snapshot.to_point(WrapPoint::new(new_start.0, 0), Bias::Left);
 382            let start_bound = Bound::Included(new_buffer_start);
 383            let start_block_ix = match self.blocks[last_block_ix..].binary_search_by(|probe| {
 384                probe
 385                    .position
 386                    .to_point(buffer)
 387                    .cmp(&new_buffer_start)
 388                    .then(Ordering::Greater)
 389            }) {
 390                Ok(ix) | Err(ix) => last_block_ix + ix,
 391            };
 392
 393            let end_bound;
 394            let end_block_ix = if new_end.0 > wrap_snapshot.max_point().row() {
 395                end_bound = Bound::Unbounded;
 396                self.blocks.len()
 397            } else {
 398                let new_buffer_end =
 399                    wrap_snapshot.to_point(WrapPoint::new(new_end.0, 0), Bias::Left);
 400                end_bound = Bound::Excluded(new_buffer_end);
 401                match self.blocks[start_block_ix..].binary_search_by(|probe| {
 402                    probe
 403                        .position
 404                        .to_point(buffer)
 405                        .cmp(&new_buffer_end)
 406                        .then(Ordering::Greater)
 407                }) {
 408                    Ok(ix) | Err(ix) => start_block_ix + ix,
 409                }
 410            };
 411            last_block_ix = end_block_ix;
 412
 413            debug_assert!(blocks_in_edit.is_empty());
 414            blocks_in_edit.extend(
 415                self.blocks[start_block_ix..end_block_ix]
 416                    .iter()
 417                    .map(|block| {
 418                        let mut position = block.position.to_point(buffer);
 419                        match block.disposition {
 420                            BlockDisposition::Above => position.column = 0,
 421                            BlockDisposition::Below => {
 422                                position.column = buffer.line_len(MultiBufferRow(position.row))
 423                            }
 424                        }
 425                        let position = wrap_snapshot.make_wrap_point(position, Bias::Left);
 426                        (position.row(), TransformBlock::Custom(block.clone()))
 427                    }),
 428            );
 429
 430            if buffer.show_headers() {
 431                blocks_in_edit.extend(BlockMap::header_blocks(
 432                    self.show_excerpt_controls,
 433                    self.excerpt_footer_height,
 434                    self.buffer_header_height,
 435                    self.excerpt_header_height,
 436                    buffer,
 437                    (start_bound, end_bound),
 438                    wrap_snapshot,
 439                ));
 440            }
 441
 442            BlockMap::sort_blocks(&mut blocks_in_edit);
 443
 444            // For each of these blocks, insert a new isomorphic transform preceding the block,
 445            // and then insert the block itself.
 446            for (block_row, block) in blocks_in_edit.drain(..) {
 447                let insertion_row = match block.disposition() {
 448                    BlockDisposition::Above => block_row,
 449                    BlockDisposition::Below => block_row + 1,
 450                };
 451                let extent_before_block = insertion_row - new_transforms.summary().input_rows;
 452                push_isomorphic(&mut new_transforms, extent_before_block);
 453                new_transforms.push(Transform::block(block), &());
 454            }
 455
 456            old_end = WrapRow(old_end.0.min(old_row_count));
 457            new_end = WrapRow(new_end.0.min(new_row_count));
 458
 459            // Insert an isomorphic transform after the final block.
 460            let extent_after_last_block = new_end.0 - new_transforms.summary().input_rows;
 461            push_isomorphic(&mut new_transforms, extent_after_last_block);
 462
 463            // Preserve any portion of the old transform after this edit.
 464            let extent_after_edit = cursor.start().0 - old_end.0;
 465            push_isomorphic(&mut new_transforms, extent_after_edit);
 466        }
 467
 468        new_transforms.append(cursor.suffix(&()), &());
 469        debug_assert_eq!(
 470            new_transforms.summary().input_rows,
 471            wrap_snapshot.max_point().row() + 1
 472        );
 473
 474        drop(cursor);
 475        *transforms = new_transforms;
 476    }
 477
 478    pub fn replace_renderers(&mut self, mut renderers: HashMap<BlockId, RenderBlock>) {
 479        for block in &mut self.blocks {
 480            if let Some(render) = renderers.remove(&block.id) {
 481                *block.render.lock() = render;
 482            }
 483        }
 484    }
 485
 486    pub fn show_excerpt_controls(&self) -> bool {
 487        self.show_excerpt_controls
 488    }
 489
 490    pub fn header_blocks<'a, 'b: 'a, 'c: 'a + 'b, R, T>(
 491        show_excerpt_controls: bool,
 492        excerpt_footer_height: u8,
 493        buffer_header_height: u8,
 494        excerpt_header_height: u8,
 495        buffer: &'b multi_buffer::MultiBufferSnapshot,
 496        range: R,
 497        wrap_snapshot: &'c WrapSnapshot,
 498    ) -> impl Iterator<Item = (u32, TransformBlock)> + 'b
 499    where
 500        R: RangeBounds<T>,
 501        T: multi_buffer::ToOffset,
 502    {
 503        buffer
 504            .excerpt_boundaries_in_range(range)
 505            .flat_map(move |excerpt_boundary| {
 506                let wrap_row = wrap_snapshot
 507                    .make_wrap_point(Point::new(excerpt_boundary.row.0, 0), Bias::Left)
 508                    .row();
 509
 510                [
 511                    show_excerpt_controls
 512                        .then(|| {
 513                            excerpt_boundary.prev.as_ref().map(|prev| {
 514                                (
 515                                    wrap_row,
 516                                    TransformBlock::ExcerptFooter {
 517                                        id: prev.id,
 518                                        height: excerpt_footer_height,
 519                                        disposition: if excerpt_boundary.next.is_some() {
 520                                            BlockDisposition::Above
 521                                        } else {
 522                                            BlockDisposition::Below
 523                                        },
 524                                    },
 525                                )
 526                            })
 527                        })
 528                        .flatten(),
 529                    excerpt_boundary.next.map(|next| {
 530                        let starts_new_buffer = excerpt_boundary
 531                            .prev
 532                            .map_or(true, |prev| prev.buffer_id != next.buffer_id);
 533
 534                        (
 535                            wrap_row,
 536                            TransformBlock::ExcerptHeader {
 537                                id: next.id,
 538                                buffer: next.buffer,
 539                                range: next.range,
 540                                height: if starts_new_buffer {
 541                                    buffer_header_height
 542                                } else {
 543                                    excerpt_header_height
 544                                },
 545                                starts_new_buffer,
 546                                show_excerpt_controls,
 547                            },
 548                        )
 549                    }),
 550                ]
 551            })
 552            .flatten()
 553    }
 554
 555    pub(crate) fn sort_blocks<B: BlockLike>(blocks: &mut Vec<(u32, B)>) {
 556        // Place excerpt headers and footers above custom blocks on the same row
 557        blocks.sort_unstable_by(|(row_a, block_a), (row_b, block_b)| {
 558            row_a.cmp(row_b).then_with(|| {
 559                block_a
 560                    .disposition()
 561                    .cmp(&block_b.disposition())
 562                    .then_with(|| match ((block_a.block_type()), (block_b.block_type())) {
 563                        (BlockType::Footer, BlockType::Footer) => Ordering::Equal,
 564                        (BlockType::Footer, _) => Ordering::Less,
 565                        (_, BlockType::Footer) => Ordering::Greater,
 566                        (BlockType::Header, BlockType::Header) => Ordering::Equal,
 567                        (BlockType::Header, _) => Ordering::Less,
 568                        (_, BlockType::Header) => Ordering::Greater,
 569                        (BlockType::Custom(a_id), BlockType::Custom(b_id)) => a_id.cmp(&b_id),
 570                    })
 571            })
 572        });
 573    }
 574}
 575
 576fn push_isomorphic(tree: &mut SumTree<Transform>, rows: u32) {
 577    if rows == 0 {
 578        return;
 579    }
 580
 581    let mut extent = Some(rows);
 582    tree.update_last(
 583        |last_transform| {
 584            if last_transform.is_isomorphic() {
 585                let extent = extent.take().unwrap();
 586                last_transform.summary.input_rows += extent;
 587                last_transform.summary.output_rows += extent;
 588            }
 589        },
 590        &(),
 591    );
 592    if let Some(extent) = extent {
 593        tree.push(Transform::isomorphic(extent), &());
 594    }
 595}
 596
 597impl BlockPoint {
 598    pub fn new(row: u32, column: u32) -> Self {
 599        Self(Point::new(row, column))
 600    }
 601}
 602
 603impl Deref for BlockPoint {
 604    type Target = Point;
 605
 606    fn deref(&self) -> &Self::Target {
 607        &self.0
 608    }
 609}
 610
 611impl std::ops::DerefMut for BlockPoint {
 612    fn deref_mut(&mut self) -> &mut Self::Target {
 613        &mut self.0
 614    }
 615}
 616
 617impl<'a> Deref for BlockMapReader<'a> {
 618    type Target = BlockSnapshot;
 619
 620    fn deref(&self) -> &Self::Target {
 621        &self.snapshot
 622    }
 623}
 624
 625impl<'a> DerefMut for BlockMapReader<'a> {
 626    fn deref_mut(&mut self) -> &mut Self::Target {
 627        &mut self.snapshot
 628    }
 629}
 630
 631impl<'a> BlockMapReader<'a> {
 632    pub fn row_for_block(&self, block_id: BlockId) -> Option<BlockRow> {
 633        let block = self.blocks.iter().find(|block| block.id == block_id)?;
 634        let buffer_row = block
 635            .position
 636            .to_point(self.wrap_snapshot.buffer_snapshot())
 637            .row;
 638        let wrap_row = self
 639            .wrap_snapshot
 640            .make_wrap_point(Point::new(buffer_row, 0), Bias::Left)
 641            .row();
 642        let start_wrap_row = WrapRow(
 643            self.wrap_snapshot
 644                .prev_row_boundary(WrapPoint::new(wrap_row, 0)),
 645        );
 646        let end_wrap_row = WrapRow(
 647            self.wrap_snapshot
 648                .next_row_boundary(WrapPoint::new(wrap_row, 0))
 649                .unwrap_or(self.wrap_snapshot.max_point().row() + 1),
 650        );
 651
 652        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 653        cursor.seek(&start_wrap_row, Bias::Left, &());
 654        while let Some(transform) = cursor.item() {
 655            if cursor.start().0 > end_wrap_row {
 656                break;
 657            }
 658
 659            if let Some(BlockType::Custom(id)) =
 660                transform.block.as_ref().map(|block| block.block_type())
 661            {
 662                if id == block_id {
 663                    return Some(cursor.start().1);
 664                }
 665            }
 666            cursor.next(&());
 667        }
 668
 669        None
 670    }
 671}
 672
 673impl<'a> BlockMapWriter<'a> {
 674    pub fn insert(
 675        &mut self,
 676        blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
 677    ) -> Vec<BlockId> {
 678        let mut ids = Vec::new();
 679        let mut edits = Patch::default();
 680        let wrap_snapshot = &*self.0.wrap_snapshot.borrow();
 681        let buffer = wrap_snapshot.buffer_snapshot();
 682
 683        for block in blocks {
 684            let id = BlockId(self.0.next_block_id.fetch_add(1, SeqCst));
 685            ids.push(id);
 686
 687            let position = block.position;
 688            let point = position.to_point(buffer);
 689            let wrap_row = wrap_snapshot
 690                .make_wrap_point(Point::new(point.row, 0), Bias::Left)
 691                .row();
 692            let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 693            let end_row = wrap_snapshot
 694                .next_row_boundary(WrapPoint::new(wrap_row, 0))
 695                .unwrap_or(wrap_snapshot.max_point().row() + 1);
 696
 697            let block_ix = match self
 698                .0
 699                .blocks
 700                .binary_search_by(|probe| probe.position.cmp(&position, buffer))
 701            {
 702                Ok(ix) | Err(ix) => ix,
 703            };
 704            self.0.blocks.insert(
 705                block_ix,
 706                Arc::new(Block {
 707                    id,
 708                    position,
 709                    height: block.height,
 710                    render: Mutex::new(block.render),
 711                    disposition: block.disposition,
 712                    style: block.style,
 713                }),
 714            );
 715
 716            edits = edits.compose([Edit {
 717                old: start_row..end_row,
 718                new: start_row..end_row,
 719            }]);
 720        }
 721
 722        self.0.sync(wrap_snapshot, edits);
 723        ids
 724    }
 725
 726    pub fn replace(&mut self, mut heights_and_renderers: HashMap<BlockId, (u8, RenderBlock)>) {
 727        let wrap_snapshot = &*self.0.wrap_snapshot.borrow();
 728        let buffer = wrap_snapshot.buffer_snapshot();
 729        let mut edits = Patch::default();
 730        let mut last_block_buffer_row = None;
 731
 732        for block in &mut self.0.blocks {
 733            if let Some((new_height, render)) = heights_and_renderers.remove(&block.id) {
 734                if block.height != new_height {
 735                    let new_block = Block {
 736                        id: block.id,
 737                        position: block.position,
 738                        height: new_height,
 739                        style: block.style,
 740                        render: Mutex::new(render),
 741                        disposition: block.disposition,
 742                    };
 743                    *block = Arc::new(new_block);
 744
 745                    let buffer_row = block.position.to_point(buffer).row;
 746                    if last_block_buffer_row != Some(buffer_row) {
 747                        last_block_buffer_row = Some(buffer_row);
 748                        let wrap_row = wrap_snapshot
 749                            .make_wrap_point(Point::new(buffer_row, 0), Bias::Left)
 750                            .row();
 751                        let start_row =
 752                            wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 753                        let end_row = wrap_snapshot
 754                            .next_row_boundary(WrapPoint::new(wrap_row, 0))
 755                            .unwrap_or(wrap_snapshot.max_point().row() + 1);
 756                        edits.push(Edit {
 757                            old: start_row..end_row,
 758                            new: start_row..end_row,
 759                        })
 760                    }
 761                }
 762            }
 763        }
 764
 765        self.0.sync(wrap_snapshot, edits);
 766    }
 767
 768    pub fn remove(&mut self, block_ids: HashSet<BlockId>) {
 769        let wrap_snapshot = &*self.0.wrap_snapshot.borrow();
 770        let buffer = wrap_snapshot.buffer_snapshot();
 771        let mut edits = Patch::default();
 772        let mut last_block_buffer_row = None;
 773        self.0.blocks.retain(|block| {
 774            if block_ids.contains(&block.id) {
 775                let buffer_row = block.position.to_point(buffer).row;
 776                if last_block_buffer_row != Some(buffer_row) {
 777                    last_block_buffer_row = Some(buffer_row);
 778                    let wrap_row = wrap_snapshot
 779                        .make_wrap_point(Point::new(buffer_row, 0), Bias::Left)
 780                        .row();
 781                    let start_row = wrap_snapshot.prev_row_boundary(WrapPoint::new(wrap_row, 0));
 782                    let end_row = wrap_snapshot
 783                        .next_row_boundary(WrapPoint::new(wrap_row, 0))
 784                        .unwrap_or(wrap_snapshot.max_point().row() + 1);
 785                    edits.push(Edit {
 786                        old: start_row..end_row,
 787                        new: start_row..end_row,
 788                    })
 789                }
 790                false
 791            } else {
 792                true
 793            }
 794        });
 795        self.0.sync(wrap_snapshot, edits);
 796    }
 797}
 798
 799impl BlockSnapshot {
 800    #[cfg(test)]
 801    pub fn text(&self) -> String {
 802        self.chunks(
 803            0..self.transforms.summary().output_rows,
 804            false,
 805            Highlights::default(),
 806        )
 807        .map(|chunk| chunk.text)
 808        .collect()
 809    }
 810
 811    pub(crate) fn chunks<'a>(
 812        &'a self,
 813        rows: Range<u32>,
 814        language_aware: bool,
 815        highlights: Highlights<'a>,
 816    ) -> BlockChunks<'a> {
 817        let max_output_row = cmp::min(rows.end, self.transforms.summary().output_rows);
 818        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 819        let input_end = {
 820            cursor.seek(&BlockRow(rows.end), Bias::Right, &());
 821            let overshoot = if cursor
 822                .item()
 823                .map_or(false, |transform| transform.is_isomorphic())
 824            {
 825                rows.end - cursor.start().0 .0
 826            } else {
 827                0
 828            };
 829            cursor.start().1 .0 + overshoot
 830        };
 831        let input_start = {
 832            cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 833            let overshoot = if cursor
 834                .item()
 835                .map_or(false, |transform| transform.is_isomorphic())
 836            {
 837                rows.start - cursor.start().0 .0
 838            } else {
 839                0
 840            };
 841            cursor.start().1 .0 + overshoot
 842        };
 843        BlockChunks {
 844            input_chunks: self.wrap_snapshot.chunks(
 845                input_start..input_end,
 846                language_aware,
 847                highlights,
 848            ),
 849            input_chunk: Default::default(),
 850            transforms: cursor,
 851            output_row: rows.start,
 852            max_output_row,
 853        }
 854    }
 855
 856    pub(super) fn buffer_rows(&self, start_row: BlockRow) -> BlockBufferRows {
 857        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 858        cursor.seek(&start_row, Bias::Right, &());
 859        let (output_start, input_start) = cursor.start();
 860        let overshoot = if cursor.item().map_or(false, |t| t.is_isomorphic()) {
 861            start_row.0 - output_start.0
 862        } else {
 863            0
 864        };
 865        let input_start_row = input_start.0 + overshoot;
 866        BlockBufferRows {
 867            transforms: cursor,
 868            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
 869            output_row: start_row,
 870            started: false,
 871        }
 872    }
 873
 874    pub fn blocks_in_range(
 875        &self,
 876        rows: Range<u32>,
 877    ) -> impl Iterator<Item = (u32, &TransformBlock)> {
 878        let mut cursor = self.transforms.cursor::<BlockRow>();
 879        cursor.seek(&BlockRow(rows.start), Bias::Right, &());
 880        std::iter::from_fn(move || {
 881            while let Some(transform) = cursor.item() {
 882                let start_row = cursor.start().0;
 883                if start_row >= rows.end {
 884                    break;
 885                }
 886                if let Some(block) = &transform.block {
 887                    cursor.next(&());
 888                    return Some((start_row, block));
 889                } else {
 890                    cursor.next(&());
 891                }
 892            }
 893            None
 894        })
 895    }
 896
 897    pub fn max_point(&self) -> BlockPoint {
 898        let row = self.transforms.summary().output_rows - 1;
 899        BlockPoint::new(row, self.line_len(BlockRow(row)))
 900    }
 901
 902    pub fn longest_row(&self) -> u32 {
 903        let input_row = self.wrap_snapshot.longest_row();
 904        self.to_block_point(WrapPoint::new(input_row, 0)).row
 905    }
 906
 907    pub(super) fn line_len(&self, row: BlockRow) -> u32 {
 908        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 909        cursor.seek(&BlockRow(row.0), Bias::Right, &());
 910        if let Some(transform) = cursor.item() {
 911            let (output_start, input_start) = cursor.start();
 912            let overshoot = row.0 - output_start.0;
 913            if transform.block.is_some() {
 914                0
 915            } else {
 916                self.wrap_snapshot.line_len(input_start.0 + overshoot)
 917            }
 918        } else {
 919            panic!("row out of range");
 920        }
 921    }
 922
 923    pub(super) fn is_block_line(&self, row: BlockRow) -> bool {
 924        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 925        cursor.seek(&row, Bias::Right, &());
 926        cursor.item().map_or(false, |t| t.block.is_some())
 927    }
 928
 929    pub fn clip_point(&self, point: BlockPoint, bias: Bias) -> BlockPoint {
 930        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 931        cursor.seek(&BlockRow(point.row), Bias::Right, &());
 932
 933        let max_input_row = WrapRow(self.transforms.summary().input_rows);
 934        let mut search_left =
 935            (bias == Bias::Left && cursor.start().1 .0 > 0) || cursor.end(&()).1 == max_input_row;
 936        let mut reversed = false;
 937
 938        loop {
 939            if let Some(transform) = cursor.item() {
 940                if transform.is_isomorphic() {
 941                    let (output_start_row, input_start_row) = cursor.start();
 942                    let (output_end_row, input_end_row) = cursor.end(&());
 943                    let output_start = Point::new(output_start_row.0, 0);
 944                    let input_start = Point::new(input_start_row.0, 0);
 945                    let input_end = Point::new(input_end_row.0, 0);
 946                    let input_point = if point.row >= output_end_row.0 {
 947                        let line_len = self.wrap_snapshot.line_len(input_end_row.0 - 1);
 948                        self.wrap_snapshot
 949                            .clip_point(WrapPoint::new(input_end_row.0 - 1, line_len), bias)
 950                    } else {
 951                        let output_overshoot = point.0.saturating_sub(output_start);
 952                        self.wrap_snapshot
 953                            .clip_point(WrapPoint(input_start + output_overshoot), bias)
 954                    };
 955
 956                    if (input_start..input_end).contains(&input_point.0) {
 957                        let input_overshoot = input_point.0.saturating_sub(input_start);
 958                        return BlockPoint(output_start + input_overshoot);
 959                    }
 960                }
 961
 962                if search_left {
 963                    cursor.prev(&());
 964                } else {
 965                    cursor.next(&());
 966                }
 967            } else if reversed {
 968                return self.max_point();
 969            } else {
 970                reversed = true;
 971                search_left = !search_left;
 972                cursor.seek(&BlockRow(point.row), Bias::Right, &());
 973            }
 974        }
 975    }
 976
 977    pub fn to_block_point(&self, wrap_point: WrapPoint) -> BlockPoint {
 978        let mut cursor = self.transforms.cursor::<(WrapRow, BlockRow)>();
 979        cursor.seek(&WrapRow(wrap_point.row()), Bias::Right, &());
 980        if let Some(transform) = cursor.item() {
 981            debug_assert!(transform.is_isomorphic());
 982        } else {
 983            return self.max_point();
 984        }
 985
 986        let (input_start_row, output_start_row) = cursor.start();
 987        let input_start = Point::new(input_start_row.0, 0);
 988        let output_start = Point::new(output_start_row.0, 0);
 989        let input_overshoot = wrap_point.0 - input_start;
 990        BlockPoint(output_start + input_overshoot)
 991    }
 992
 993    pub fn to_wrap_point(&self, block_point: BlockPoint) -> WrapPoint {
 994        let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>();
 995        cursor.seek(&BlockRow(block_point.row), Bias::Right, &());
 996        if let Some(transform) = cursor.item() {
 997            match transform.block.as_ref().map(|b| b.disposition()) {
 998                Some(BlockDisposition::Above) => WrapPoint::new(cursor.start().1 .0, 0),
 999                Some(BlockDisposition::Below) => {
1000                    let wrap_row = cursor.start().1 .0 - 1;
1001                    WrapPoint::new(wrap_row, self.wrap_snapshot.line_len(wrap_row))
1002                }
1003                None => {
1004                    let overshoot = block_point.row - cursor.start().0 .0;
1005                    let wrap_row = cursor.start().1 .0 + overshoot;
1006                    WrapPoint::new(wrap_row, block_point.column)
1007                }
1008            }
1009        } else {
1010            self.wrap_snapshot.max_point()
1011        }
1012    }
1013}
1014
1015impl Transform {
1016    fn isomorphic(rows: u32) -> Self {
1017        Self {
1018            summary: TransformSummary {
1019                input_rows: rows,
1020                output_rows: rows,
1021            },
1022            block: None,
1023        }
1024    }
1025
1026    fn block(block: TransformBlock) -> Self {
1027        Self {
1028            summary: TransformSummary {
1029                input_rows: 0,
1030                output_rows: block.height() as u32,
1031            },
1032            block: Some(block),
1033        }
1034    }
1035
1036    fn is_isomorphic(&self) -> bool {
1037        self.block.is_none()
1038    }
1039}
1040
1041impl<'a> Iterator for BlockChunks<'a> {
1042    type Item = Chunk<'a>;
1043
1044    fn next(&mut self) -> Option<Self::Item> {
1045        if self.output_row >= self.max_output_row {
1046            return None;
1047        }
1048
1049        let transform = self.transforms.item()?;
1050        if transform.block.is_some() {
1051            let block_start = self.transforms.start().0 .0;
1052            let mut block_end = self.transforms.end(&()).0 .0;
1053            self.transforms.next(&());
1054            if self.transforms.item().is_none() {
1055                block_end -= 1;
1056            }
1057
1058            let start_in_block = self.output_row - block_start;
1059            let end_in_block = cmp::min(self.max_output_row, block_end) - block_start;
1060            let line_count = end_in_block - start_in_block;
1061            self.output_row += line_count;
1062
1063            return Some(Chunk {
1064                text: unsafe { std::str::from_utf8_unchecked(&NEWLINES[..line_count as usize]) },
1065                ..Default::default()
1066            });
1067        }
1068
1069        if self.input_chunk.text.is_empty() {
1070            if let Some(input_chunk) = self.input_chunks.next() {
1071                self.input_chunk = input_chunk;
1072            } else {
1073                self.output_row += 1;
1074                if self.output_row < self.max_output_row {
1075                    self.transforms.next(&());
1076                    return Some(Chunk {
1077                        text: "\n",
1078                        ..Default::default()
1079                    });
1080                } else {
1081                    return None;
1082                }
1083            }
1084        }
1085
1086        let transform_end = self.transforms.end(&()).0 .0;
1087        let (prefix_rows, prefix_bytes) =
1088            offset_for_row(self.input_chunk.text, transform_end - self.output_row);
1089        self.output_row += prefix_rows;
1090        let (prefix, suffix) = self.input_chunk.text.split_at(prefix_bytes);
1091        self.input_chunk.text = suffix;
1092        if self.output_row == transform_end {
1093            self.transforms.next(&());
1094        }
1095
1096        Some(Chunk {
1097            text: prefix,
1098            ..self.input_chunk.clone()
1099        })
1100    }
1101}
1102
1103impl<'a> Iterator for BlockBufferRows<'a> {
1104    type Item = Option<BlockRow>;
1105
1106    fn next(&mut self) -> Option<Self::Item> {
1107        if self.started {
1108            self.output_row.0 += 1;
1109        } else {
1110            self.started = true;
1111        }
1112
1113        if self.output_row.0 >= self.transforms.end(&()).0 .0 {
1114            self.transforms.next(&());
1115        }
1116
1117        let transform = self.transforms.item()?;
1118        if transform.block.is_some() {
1119            Some(None)
1120        } else {
1121            Some(self.input_buffer_rows.next().unwrap().map(BlockRow))
1122        }
1123    }
1124}
1125
1126impl sum_tree::Item for Transform {
1127    type Summary = TransformSummary;
1128
1129    fn summary(&self) -> Self::Summary {
1130        self.summary.clone()
1131    }
1132}
1133
1134impl sum_tree::Summary for TransformSummary {
1135    type Context = ();
1136
1137    fn add_summary(&mut self, summary: &Self, _: &()) {
1138        self.input_rows += summary.input_rows;
1139        self.output_rows += summary.output_rows;
1140    }
1141}
1142
1143impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapRow {
1144    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1145        self.0 += summary.input_rows;
1146    }
1147}
1148
1149impl<'a> sum_tree::Dimension<'a, TransformSummary> for BlockRow {
1150    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1151        self.0 += summary.output_rows;
1152    }
1153}
1154
1155impl BlockDisposition {
1156    fn is_below(&self) -> bool {
1157        matches!(self, BlockDisposition::Below)
1158    }
1159}
1160
1161impl<'a> Deref for BlockContext<'a, '_> {
1162    type Target = WindowContext<'a>;
1163
1164    fn deref(&self) -> &Self::Target {
1165        self.context
1166    }
1167}
1168
1169impl DerefMut for BlockContext<'_, '_> {
1170    fn deref_mut(&mut self) -> &mut Self::Target {
1171        self.context
1172    }
1173}
1174
1175impl Block {
1176    pub fn render(&self, cx: &mut BlockContext) -> AnyElement {
1177        self.render.lock()(cx)
1178    }
1179
1180    pub fn position(&self) -> &Anchor {
1181        &self.position
1182    }
1183
1184    pub fn style(&self) -> BlockStyle {
1185        self.style
1186    }
1187}
1188
1189impl Debug for Block {
1190    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1191        f.debug_struct("Block")
1192            .field("id", &self.id)
1193            .field("position", &self.position)
1194            .field("disposition", &self.disposition)
1195            .finish()
1196    }
1197}
1198
1199// Count the number of bytes prior to a target point. If the string doesn't contain the target
1200// point, return its total extent. Otherwise return the target point itself.
1201fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
1202    let mut row = 0;
1203    let mut offset = 0;
1204    for (ix, line) in s.split('\n').enumerate() {
1205        if ix > 0 {
1206            row += 1;
1207            offset += 1;
1208        }
1209        if row >= target {
1210            break;
1211        }
1212        offset += line.len();
1213    }
1214    (row, offset)
1215}
1216
1217#[cfg(test)]
1218mod tests {
1219    use std::env;
1220
1221    use super::*;
1222    use crate::display_map::inlay_map::InlayMap;
1223    use crate::display_map::{fold_map::FoldMap, tab_map::TabMap, wrap_map::WrapMap};
1224    use gpui::{div, font, px, AssetSource, Element};
1225    use multi_buffer::MultiBuffer;
1226    use rand::prelude::*;
1227    use settings::SettingsStore;
1228    use util::RandomCharIter;
1229
1230    #[gpui::test]
1231    fn test_offset_for_row() {
1232        assert_eq!(offset_for_row("", 0), (0, 0));
1233        assert_eq!(offset_for_row("", 1), (0, 0));
1234        assert_eq!(offset_for_row("abcd", 0), (0, 0));
1235        assert_eq!(offset_for_row("abcd", 1), (0, 4));
1236        assert_eq!(offset_for_row("\n", 0), (0, 0));
1237        assert_eq!(offset_for_row("\n", 1), (1, 1));
1238        assert_eq!(offset_for_row("abc\ndef\nghi", 0), (0, 0));
1239        assert_eq!(offset_for_row("abc\ndef\nghi", 1), (1, 4));
1240        assert_eq!(offset_for_row("abc\ndef\nghi", 2), (2, 8));
1241        assert_eq!(offset_for_row("abc\ndef\nghi", 3), (2, 11));
1242    }
1243
1244    #[gpui::test]
1245    fn test_basic_blocks(cx: &mut gpui::TestAppContext) {
1246        cx.update(|cx| init_test(cx));
1247
1248        let text = "aaa\nbbb\nccc\nddd";
1249
1250        let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
1251        let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
1252        let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1253        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1254        let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
1255        let (mut tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 1.try_into().unwrap());
1256        let (wrap_map, wraps_snapshot) =
1257            cx.update(|cx| WrapMap::new(tab_snapshot, font("Helvetica"), px(14.0), None, cx));
1258        let mut block_map = BlockMap::new(wraps_snapshot.clone(), true, 1, 1, 1);
1259
1260        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1261        let block_ids = writer.insert(vec![
1262            BlockProperties {
1263                style: BlockStyle::Fixed,
1264                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
1265                height: 1,
1266                disposition: BlockDisposition::Above,
1267                render: Box::new(|_| div().into_any()),
1268            },
1269            BlockProperties {
1270                style: BlockStyle::Fixed,
1271                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
1272                height: 2,
1273                disposition: BlockDisposition::Above,
1274                render: Box::new(|_| div().into_any()),
1275            },
1276            BlockProperties {
1277                style: BlockStyle::Fixed,
1278                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
1279                height: 3,
1280                disposition: BlockDisposition::Below,
1281                render: Box::new(|_| div().into_any()),
1282            },
1283        ]);
1284
1285        let snapshot = block_map.read(wraps_snapshot, Default::default());
1286        assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
1287
1288        let blocks = snapshot
1289            .blocks_in_range(0..8)
1290            .map(|(start_row, block)| {
1291                let block = block.as_custom().unwrap();
1292                (start_row..start_row + block.height as u32, block.id)
1293            })
1294            .collect::<Vec<_>>();
1295
1296        // When multiple blocks are on the same line, the newer blocks appear first.
1297        assert_eq!(
1298            blocks,
1299            &[
1300                (1..2, block_ids[0]),
1301                (2..4, block_ids[1]),
1302                (7..10, block_ids[2]),
1303            ]
1304        );
1305
1306        assert_eq!(
1307            snapshot.to_block_point(WrapPoint::new(0, 3)),
1308            BlockPoint::new(0, 3)
1309        );
1310        assert_eq!(
1311            snapshot.to_block_point(WrapPoint::new(1, 0)),
1312            BlockPoint::new(4, 0)
1313        );
1314        assert_eq!(
1315            snapshot.to_block_point(WrapPoint::new(3, 3)),
1316            BlockPoint::new(6, 3)
1317        );
1318
1319        assert_eq!(
1320            snapshot.to_wrap_point(BlockPoint::new(0, 3)),
1321            WrapPoint::new(0, 3)
1322        );
1323        assert_eq!(
1324            snapshot.to_wrap_point(BlockPoint::new(1, 0)),
1325            WrapPoint::new(1, 0)
1326        );
1327        assert_eq!(
1328            snapshot.to_wrap_point(BlockPoint::new(3, 0)),
1329            WrapPoint::new(1, 0)
1330        );
1331        assert_eq!(
1332            snapshot.to_wrap_point(BlockPoint::new(7, 0)),
1333            WrapPoint::new(3, 3)
1334        );
1335
1336        assert_eq!(
1337            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Left),
1338            BlockPoint::new(0, 3)
1339        );
1340        assert_eq!(
1341            snapshot.clip_point(BlockPoint::new(1, 0), Bias::Right),
1342            BlockPoint::new(4, 0)
1343        );
1344        assert_eq!(
1345            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Left),
1346            BlockPoint::new(0, 3)
1347        );
1348        assert_eq!(
1349            snapshot.clip_point(BlockPoint::new(1, 1), Bias::Right),
1350            BlockPoint::new(4, 0)
1351        );
1352        assert_eq!(
1353            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Left),
1354            BlockPoint::new(4, 0)
1355        );
1356        assert_eq!(
1357            snapshot.clip_point(BlockPoint::new(4, 0), Bias::Right),
1358            BlockPoint::new(4, 0)
1359        );
1360        assert_eq!(
1361            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Left),
1362            BlockPoint::new(6, 3)
1363        );
1364        assert_eq!(
1365            snapshot.clip_point(BlockPoint::new(6, 3), Bias::Right),
1366            BlockPoint::new(6, 3)
1367        );
1368        assert_eq!(
1369            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Left),
1370            BlockPoint::new(6, 3)
1371        );
1372        assert_eq!(
1373            snapshot.clip_point(BlockPoint::new(7, 0), Bias::Right),
1374            BlockPoint::new(6, 3)
1375        );
1376
1377        assert_eq!(
1378            snapshot
1379                .buffer_rows(BlockRow(0))
1380                .map(|row| row.map(|r| r.0))
1381                .collect::<Vec<_>>(),
1382            &[
1383                Some(0),
1384                None,
1385                None,
1386                None,
1387                Some(1),
1388                Some(2),
1389                Some(3),
1390                None,
1391                None,
1392                None
1393            ]
1394        );
1395
1396        // Insert a line break, separating two block decorations into separate lines.
1397        let buffer_snapshot = buffer.update(cx, |buffer, cx| {
1398            buffer.edit([(Point::new(1, 1)..Point::new(1, 1), "!!!\n")], None, cx);
1399            buffer.snapshot(cx)
1400        });
1401
1402        let (inlay_snapshot, inlay_edits) =
1403            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
1404        let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
1405        let (tab_snapshot, tab_edits) =
1406            tab_map.sync(fold_snapshot, fold_edits, 4.try_into().unwrap());
1407        let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1408            wrap_map.sync(tab_snapshot, tab_edits, cx)
1409        });
1410        let snapshot = block_map.read(wraps_snapshot, wrap_edits);
1411        assert_eq!(snapshot.text(), "aaa\n\nb!!!\n\n\nbb\nccc\nddd\n\n\n");
1412    }
1413
1414    #[gpui::test]
1415    fn test_replace_with_heights(cx: &mut gpui::TestAppContext) {
1416        let _update = cx.update(|cx| init_test(cx));
1417
1418        let text = "aaa\nbbb\nccc\nddd";
1419
1420        let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
1421        let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
1422        let _subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
1423        let (_inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1424        let (_fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
1425        let (_tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 1.try_into().unwrap());
1426        let (_wrap_map, wraps_snapshot) =
1427            cx.update(|cx| WrapMap::new(tab_snapshot, font("Helvetica"), px(14.0), None, cx));
1428        let mut block_map = BlockMap::new(wraps_snapshot.clone(), false, 1, 1, 0);
1429
1430        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1431        let block_ids = writer.insert(vec![
1432            BlockProperties {
1433                style: BlockStyle::Fixed,
1434                position: buffer_snapshot.anchor_after(Point::new(1, 0)),
1435                height: 1,
1436                disposition: BlockDisposition::Above,
1437                render: Box::new(|_| div().into_any()),
1438            },
1439            BlockProperties {
1440                style: BlockStyle::Fixed,
1441                position: buffer_snapshot.anchor_after(Point::new(1, 2)),
1442                height: 2,
1443                disposition: BlockDisposition::Above,
1444                render: Box::new(|_| div().into_any()),
1445            },
1446            BlockProperties {
1447                style: BlockStyle::Fixed,
1448                position: buffer_snapshot.anchor_after(Point::new(3, 3)),
1449                height: 3,
1450                disposition: BlockDisposition::Below,
1451                render: Box::new(|_| div().into_any()),
1452            },
1453        ]);
1454
1455        {
1456            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1457            assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
1458
1459            let mut block_map_writer = block_map.write(wraps_snapshot.clone(), Default::default());
1460
1461            let mut hash_map = HashMap::default();
1462            let render: RenderBlock = Box::new(|_| div().into_any());
1463            hash_map.insert(block_ids[0], (2_u8, render));
1464            block_map_writer.replace(hash_map);
1465            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1466            assert_eq!(snapshot.text(), "aaa\n\n\n\n\nbbb\nccc\nddd\n\n\n");
1467        }
1468
1469        {
1470            let mut block_map_writer = block_map.write(wraps_snapshot.clone(), Default::default());
1471
1472            let mut hash_map = HashMap::default();
1473            let render: RenderBlock = Box::new(|_| div().into_any());
1474            hash_map.insert(block_ids[0], (1_u8, render));
1475            block_map_writer.replace(hash_map);
1476
1477            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1478            assert_eq!(snapshot.text(), "aaa\n\n\n\nbbb\nccc\nddd\n\n\n");
1479        }
1480
1481        {
1482            let mut block_map_writer = block_map.write(wraps_snapshot.clone(), Default::default());
1483
1484            let mut hash_map = HashMap::default();
1485            let render: RenderBlock = Box::new(|_| div().into_any());
1486            hash_map.insert(block_ids[0], (0_u8, render));
1487            block_map_writer.replace(hash_map);
1488
1489            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1490            assert_eq!(snapshot.text(), "aaa\n\n\nbbb\nccc\nddd\n\n\n");
1491        }
1492
1493        {
1494            let mut block_map_writer = block_map.write(wraps_snapshot.clone(), Default::default());
1495
1496            let mut hash_map = HashMap::default();
1497            let render: RenderBlock = Box::new(|_| div().into_any());
1498            hash_map.insert(block_ids[0], (3_u8, render));
1499            block_map_writer.replace(hash_map);
1500
1501            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1502            assert_eq!(snapshot.text(), "aaa\n\n\n\n\n\nbbb\nccc\nddd\n\n\n");
1503        }
1504
1505        {
1506            let mut block_map_writer = block_map.write(wraps_snapshot.clone(), Default::default());
1507
1508            let mut hash_map = HashMap::default();
1509            let render: RenderBlock = Box::new(|_| div().into_any());
1510            hash_map.insert(block_ids[0], (3_u8, render));
1511            block_map_writer.replace(hash_map);
1512
1513            let snapshot = block_map.read(wraps_snapshot.clone(), Default::default());
1514            // Same height as before, should remain the same
1515            assert_eq!(snapshot.text(), "aaa\n\n\n\n\n\nbbb\nccc\nddd\n\n\n");
1516        }
1517    }
1518
1519    #[cfg(target_os = "macos")]
1520    #[gpui::test]
1521    fn test_blocks_on_wrapped_lines(cx: &mut gpui::TestAppContext) {
1522        cx.update(|cx| init_test(cx));
1523
1524        let _font_id = cx.text_system().font_id(&font("Helvetica")).unwrap();
1525
1526        let text = "one two three\nfour five six\nseven eight";
1527
1528        let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
1529        let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
1530        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1531        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
1532        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
1533        let (_, wraps_snapshot) = cx.update(|cx| {
1534            WrapMap::new(tab_snapshot, font("Helvetica"), px(14.0), Some(px(60.)), cx)
1535        });
1536        let mut block_map = BlockMap::new(wraps_snapshot.clone(), true, 1, 1, 0);
1537
1538        let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
1539        writer.insert(vec![
1540            BlockProperties {
1541                style: BlockStyle::Fixed,
1542                position: buffer_snapshot.anchor_after(Point::new(1, 12)),
1543                disposition: BlockDisposition::Above,
1544                render: Box::new(|_| div().into_any()),
1545                height: 1,
1546            },
1547            BlockProperties {
1548                style: BlockStyle::Fixed,
1549                position: buffer_snapshot.anchor_after(Point::new(1, 1)),
1550                disposition: BlockDisposition::Below,
1551                render: Box::new(|_| div().into_any()),
1552                height: 1,
1553            },
1554        ]);
1555
1556        // Blocks with an 'above' disposition go above their corresponding buffer line.
1557        // Blocks with a 'below' disposition go below their corresponding buffer line.
1558        let snapshot = block_map.read(wraps_snapshot, Default::default());
1559        assert_eq!(
1560            snapshot.text(),
1561            "one two \nthree\n\nfour five \nsix\n\nseven \neight"
1562        );
1563    }
1564
1565    #[gpui::test(iterations = 100)]
1566    fn test_random_blocks(cx: &mut gpui::TestAppContext, mut rng: StdRng) {
1567        cx.update(|cx| init_test(cx));
1568
1569        let operations = env::var("OPERATIONS")
1570            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1571            .unwrap_or(10);
1572
1573        let wrap_width = if rng.gen_bool(0.2) {
1574            None
1575        } else {
1576            Some(px(rng.gen_range(0.0..=100.0)))
1577        };
1578        let tab_size = 1.try_into().unwrap();
1579        let font_size = px(14.0);
1580        let buffer_start_header_height = rng.gen_range(1..=5);
1581        let excerpt_header_height = rng.gen_range(1..=5);
1582        let excerpt_footer_height = rng.gen_range(1..=5);
1583
1584        log::info!("Wrap width: {:?}", wrap_width);
1585        log::info!("Excerpt Header Height: {:?}", excerpt_header_height);
1586        log::info!("Excerpt Footer Height: {:?}", excerpt_footer_height);
1587
1588        let buffer = if rng.gen() {
1589            let len = rng.gen_range(0..10);
1590            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1591            log::info!("initial buffer text: {:?}", text);
1592            cx.update(|cx| MultiBuffer::build_simple(&text, cx))
1593        } else {
1594            cx.update(|cx| MultiBuffer::build_random(&mut rng, cx))
1595        };
1596
1597        let mut buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
1598        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
1599        let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
1600        let (mut tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
1601        let (wrap_map, wraps_snapshot) = cx
1602            .update(|cx| WrapMap::new(tab_snapshot, font("Helvetica"), font_size, wrap_width, cx));
1603        let mut block_map = BlockMap::new(
1604            wraps_snapshot,
1605            true,
1606            buffer_start_header_height,
1607            excerpt_header_height,
1608            excerpt_footer_height,
1609        );
1610        let mut custom_blocks = Vec::new();
1611
1612        for _ in 0..operations {
1613            let mut buffer_edits = Vec::new();
1614            match rng.gen_range(0..=100) {
1615                0..=19 => {
1616                    let wrap_width = if rng.gen_bool(0.2) {
1617                        None
1618                    } else {
1619                        Some(px(rng.gen_range(0.0..=100.0)))
1620                    };
1621                    log::info!("Setting wrap width to {:?}", wrap_width);
1622                    wrap_map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
1623                }
1624                20..=39 => {
1625                    let block_count = rng.gen_range(1..=5);
1626                    let block_properties = (0..block_count)
1627                        .map(|_| {
1628                            let buffer = cx.update(|cx| buffer.read(cx).read(cx).clone());
1629                            let position = buffer.anchor_after(
1630                                buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Left),
1631                            );
1632
1633                            let disposition = if rng.gen() {
1634                                BlockDisposition::Above
1635                            } else {
1636                                BlockDisposition::Below
1637                            };
1638                            let height = rng.gen_range(1..5);
1639                            log::info!(
1640                                "inserting block {:?} {:?} with height {}",
1641                                disposition,
1642                                position.to_point(&buffer),
1643                                height
1644                            );
1645                            BlockProperties {
1646                                style: BlockStyle::Fixed,
1647                                position,
1648                                height,
1649                                disposition,
1650                                render: Box::new(|_| div().into_any()),
1651                            }
1652                        })
1653                        .collect::<Vec<_>>();
1654
1655                    let (inlay_snapshot, inlay_edits) =
1656                        inlay_map.sync(buffer_snapshot.clone(), vec![]);
1657                    let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
1658                    let (tab_snapshot, tab_edits) =
1659                        tab_map.sync(fold_snapshot, fold_edits, tab_size);
1660                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1661                        wrap_map.sync(tab_snapshot, tab_edits, cx)
1662                    });
1663                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1664                    let block_ids =
1665                        block_map.insert(block_properties.iter().map(|props| BlockProperties {
1666                            position: props.position,
1667                            height: props.height,
1668                            style: props.style,
1669                            render: Box::new(|_| div().into_any()),
1670                            disposition: props.disposition,
1671                        }));
1672                    for (block_id, props) in block_ids.into_iter().zip(block_properties) {
1673                        custom_blocks.push((block_id, props));
1674                    }
1675                }
1676                40..=59 if !custom_blocks.is_empty() => {
1677                    let block_count = rng.gen_range(1..=4.min(custom_blocks.len()));
1678                    let block_ids_to_remove = (0..block_count)
1679                        .map(|_| {
1680                            custom_blocks
1681                                .remove(rng.gen_range(0..custom_blocks.len()))
1682                                .0
1683                        })
1684                        .collect();
1685
1686                    let (inlay_snapshot, inlay_edits) =
1687                        inlay_map.sync(buffer_snapshot.clone(), vec![]);
1688                    let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
1689                    let (tab_snapshot, tab_edits) =
1690                        tab_map.sync(fold_snapshot, fold_edits, tab_size);
1691                    let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1692                        wrap_map.sync(tab_snapshot, tab_edits, cx)
1693                    });
1694                    let mut block_map = block_map.write(wraps_snapshot, wrap_edits);
1695                    block_map.remove(block_ids_to_remove);
1696                }
1697                _ => {
1698                    buffer.update(cx, |buffer, cx| {
1699                        let mutation_count = rng.gen_range(1..=5);
1700                        let subscription = buffer.subscribe();
1701                        buffer.randomly_mutate(&mut rng, mutation_count, cx);
1702                        buffer_snapshot = buffer.snapshot(cx);
1703                        buffer_edits.extend(subscription.consume());
1704                        log::info!("buffer text: {:?}", buffer_snapshot.text());
1705                    });
1706                }
1707            }
1708
1709            let (inlay_snapshot, inlay_edits) =
1710                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
1711            let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
1712            let (tab_snapshot, tab_edits) = tab_map.sync(fold_snapshot, fold_edits, tab_size);
1713            let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
1714                wrap_map.sync(tab_snapshot, tab_edits, cx)
1715            });
1716            let blocks_snapshot = block_map.read(wraps_snapshot.clone(), wrap_edits);
1717            assert_eq!(
1718                blocks_snapshot.transforms.summary().input_rows,
1719                wraps_snapshot.max_point().row() + 1
1720            );
1721            log::info!("blocks text: {:?}", blocks_snapshot.text());
1722
1723            let mut expected_blocks = Vec::new();
1724            expected_blocks.extend(custom_blocks.iter().map(|(id, block)| {
1725                let mut position = block.position.to_point(&buffer_snapshot);
1726                match block.disposition {
1727                    BlockDisposition::Above => {
1728                        position.column = 0;
1729                    }
1730                    BlockDisposition::Below => {
1731                        position.column = buffer_snapshot.line_len(MultiBufferRow(position.row));
1732                    }
1733                };
1734                let row = wraps_snapshot.make_wrap_point(position, Bias::Left).row();
1735                (
1736                    row,
1737                    ExpectedBlock::Custom {
1738                        disposition: block.disposition,
1739                        id: *id,
1740                        height: block.height,
1741                    },
1742                )
1743            }));
1744
1745            // Note that this needs to be synced with the related section in BlockMap::sync
1746            expected_blocks.extend(
1747                BlockMap::header_blocks(
1748                    true,
1749                    excerpt_footer_height,
1750                    buffer_start_header_height,
1751                    excerpt_header_height,
1752                    &buffer_snapshot,
1753                    0..,
1754                    &wraps_snapshot,
1755                )
1756                .map(|(row, block)| (row, block.into())),
1757            );
1758
1759            BlockMap::sort_blocks(&mut expected_blocks);
1760
1761            let mut sorted_blocks_iter = expected_blocks.into_iter().peekable();
1762
1763            let input_buffer_rows = buffer_snapshot
1764                .buffer_rows(MultiBufferRow(0))
1765                .collect::<Vec<_>>();
1766            let mut expected_buffer_rows = Vec::new();
1767            let mut expected_text = String::new();
1768            let mut expected_block_positions = Vec::new();
1769            let input_text = wraps_snapshot.text();
1770            for (row, input_line) in input_text.split('\n').enumerate() {
1771                let row = row as u32;
1772                if row > 0 {
1773                    expected_text.push('\n');
1774                }
1775
1776                let buffer_row = input_buffer_rows[wraps_snapshot
1777                    .to_point(WrapPoint::new(row, 0), Bias::Left)
1778                    .row as usize];
1779
1780                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1781                    if *block_row == row && block.disposition() == BlockDisposition::Above {
1782                        let (_, block) = sorted_blocks_iter.next().unwrap();
1783                        let height = block.height() as usize;
1784                        expected_block_positions
1785                            .push((expected_text.matches('\n').count() as u32, block));
1786                        let text = "\n".repeat(height);
1787                        expected_text.push_str(&text);
1788                        for _ in 0..height {
1789                            expected_buffer_rows.push(None);
1790                        }
1791                    } else {
1792                        break;
1793                    }
1794                }
1795
1796                let soft_wrapped = wraps_snapshot.to_tab_point(WrapPoint::new(row, 0)).column() > 0;
1797                expected_buffer_rows.push(if soft_wrapped { None } else { buffer_row });
1798                expected_text.push_str(input_line);
1799
1800                while let Some((block_row, block)) = sorted_blocks_iter.peek() {
1801                    if *block_row == row && block.disposition() == BlockDisposition::Below {
1802                        let (_, block) = sorted_blocks_iter.next().unwrap();
1803                        let height = block.height() as usize;
1804                        expected_block_positions
1805                            .push((expected_text.matches('\n').count() as u32 + 1, block));
1806                        let text = "\n".repeat(height);
1807                        expected_text.push_str(&text);
1808                        for _ in 0..height {
1809                            expected_buffer_rows.push(None);
1810                        }
1811                    } else {
1812                        break;
1813                    }
1814                }
1815            }
1816
1817            let expected_lines = expected_text.split('\n').collect::<Vec<_>>();
1818            let expected_row_count = expected_lines.len();
1819            for start_row in 0..expected_row_count {
1820                let expected_text = expected_lines[start_row..].join("\n");
1821                let actual_text = blocks_snapshot
1822                    .chunks(
1823                        start_row as u32..blocks_snapshot.max_point().row + 1,
1824                        false,
1825                        Highlights::default(),
1826                    )
1827                    .map(|chunk| chunk.text)
1828                    .collect::<String>();
1829                assert_eq!(
1830                    actual_text, expected_text,
1831                    "incorrect text starting from row {}",
1832                    start_row
1833                );
1834                assert_eq!(
1835                    blocks_snapshot
1836                        .buffer_rows(BlockRow(start_row as u32))
1837                        .map(|row| row.map(|r| r.0))
1838                        .collect::<Vec<_>>(),
1839                    &expected_buffer_rows[start_row..]
1840                );
1841            }
1842
1843            assert_eq!(
1844                blocks_snapshot
1845                    .blocks_in_range(0..(expected_row_count as u32))
1846                    .map(|(row, block)| (row, block.clone().into()))
1847                    .collect::<Vec<_>>(),
1848                expected_block_positions
1849            );
1850
1851            for (block_row, block) in expected_block_positions {
1852                if let BlockType::Custom(block_id) = block.block_type() {
1853                    assert_eq!(
1854                        blocks_snapshot.row_for_block(block_id),
1855                        Some(BlockRow(block_row))
1856                    );
1857                }
1858            }
1859
1860            let mut expected_longest_rows = Vec::new();
1861            let mut longest_line_len = -1_isize;
1862            for (row, line) in expected_lines.iter().enumerate() {
1863                let row = row as u32;
1864
1865                assert_eq!(
1866                    blocks_snapshot.line_len(BlockRow(row)),
1867                    line.len() as u32,
1868                    "invalid line len for row {}",
1869                    row
1870                );
1871
1872                let line_char_count = line.chars().count() as isize;
1873                match line_char_count.cmp(&longest_line_len) {
1874                    Ordering::Less => {}
1875                    Ordering::Equal => expected_longest_rows.push(row),
1876                    Ordering::Greater => {
1877                        longest_line_len = line_char_count;
1878                        expected_longest_rows.clear();
1879                        expected_longest_rows.push(row);
1880                    }
1881                }
1882            }
1883
1884            let longest_row = blocks_snapshot.longest_row();
1885            assert!(
1886                expected_longest_rows.contains(&longest_row),
1887                "incorrect longest row {}. expected {:?} with length {}",
1888                longest_row,
1889                expected_longest_rows,
1890                longest_line_len,
1891            );
1892
1893            for row in 0..=blocks_snapshot.wrap_snapshot.max_point().row() {
1894                let wrap_point = WrapPoint::new(row, 0);
1895                let block_point = blocks_snapshot.to_block_point(wrap_point);
1896                assert_eq!(blocks_snapshot.to_wrap_point(block_point), wrap_point);
1897            }
1898
1899            let mut block_point = BlockPoint::new(0, 0);
1900            for c in expected_text.chars() {
1901                let left_point = blocks_snapshot.clip_point(block_point, Bias::Left);
1902                let left_buffer_point = blocks_snapshot.to_point(left_point, Bias::Left);
1903                assert_eq!(
1904                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(left_point)),
1905                    left_point
1906                );
1907                assert_eq!(
1908                    left_buffer_point,
1909                    buffer_snapshot.clip_point(left_buffer_point, Bias::Right),
1910                    "{:?} is not valid in buffer coordinates",
1911                    left_point
1912                );
1913
1914                let right_point = blocks_snapshot.clip_point(block_point, Bias::Right);
1915                let right_buffer_point = blocks_snapshot.to_point(right_point, Bias::Right);
1916                assert_eq!(
1917                    blocks_snapshot.to_block_point(blocks_snapshot.to_wrap_point(right_point)),
1918                    right_point
1919                );
1920                assert_eq!(
1921                    right_buffer_point,
1922                    buffer_snapshot.clip_point(right_buffer_point, Bias::Left),
1923                    "{:?} is not valid in buffer coordinates",
1924                    right_point
1925                );
1926
1927                if c == '\n' {
1928                    block_point.0 += Point::new(1, 0);
1929                } else {
1930                    block_point.column += c.len_utf8() as u32;
1931                }
1932            }
1933        }
1934
1935        #[derive(Debug, Eq, PartialEq)]
1936        enum ExpectedBlock {
1937            ExcerptHeader {
1938                height: u8,
1939                starts_new_buffer: bool,
1940            },
1941            ExcerptFooter {
1942                height: u8,
1943                disposition: BlockDisposition,
1944            },
1945            Custom {
1946                disposition: BlockDisposition,
1947                id: BlockId,
1948                height: u8,
1949            },
1950        }
1951
1952        impl BlockLike for ExpectedBlock {
1953            fn block_type(&self) -> BlockType {
1954                match self {
1955                    ExpectedBlock::Custom { id, .. } => BlockType::Custom(*id),
1956                    ExpectedBlock::ExcerptHeader { .. } => BlockType::Header,
1957                    ExpectedBlock::ExcerptFooter { .. } => BlockType::Footer,
1958                }
1959            }
1960
1961            fn disposition(&self) -> BlockDisposition {
1962                self.disposition()
1963            }
1964        }
1965
1966        impl ExpectedBlock {
1967            fn height(&self) -> u8 {
1968                match self {
1969                    ExpectedBlock::ExcerptHeader { height, .. } => *height,
1970                    ExpectedBlock::Custom { height, .. } => *height,
1971                    ExpectedBlock::ExcerptFooter { height, .. } => *height,
1972                }
1973            }
1974
1975            fn disposition(&self) -> BlockDisposition {
1976                match self {
1977                    ExpectedBlock::ExcerptHeader { .. } => BlockDisposition::Above,
1978                    ExpectedBlock::Custom { disposition, .. } => *disposition,
1979                    ExpectedBlock::ExcerptFooter { disposition, .. } => *disposition,
1980                }
1981            }
1982        }
1983
1984        impl From<TransformBlock> for ExpectedBlock {
1985            fn from(block: TransformBlock) -> Self {
1986                match block {
1987                    TransformBlock::Custom(block) => ExpectedBlock::Custom {
1988                        id: block.id,
1989                        disposition: block.disposition,
1990                        height: block.height,
1991                    },
1992                    TransformBlock::ExcerptHeader {
1993                        height,
1994                        starts_new_buffer,
1995                        ..
1996                    } => ExpectedBlock::ExcerptHeader {
1997                        height,
1998                        starts_new_buffer,
1999                    },
2000                    TransformBlock::ExcerptFooter {
2001                        height,
2002                        disposition,
2003                        ..
2004                    } => ExpectedBlock::ExcerptFooter {
2005                        height,
2006                        disposition,
2007                    },
2008                }
2009            }
2010        }
2011    }
2012
2013    fn init_test(cx: &mut gpui::AppContext) {
2014        let settings = SettingsStore::test(cx);
2015        cx.set_global(settings);
2016        theme::init(theme::LoadThemes::JustBase, cx);
2017        cx.text_system()
2018            .add_fonts(vec![assets::Assets
2019                .load("fonts/zed-mono/zed-mono-extended.ttf")
2020                .unwrap()
2021                .unwrap()])
2022            .unwrap();
2023    }
2024
2025    impl TransformBlock {
2026        fn as_custom(&self) -> Option<&Block> {
2027            match self {
2028                TransformBlock::Custom(block) => Some(block),
2029                TransformBlock::ExcerptHeader { .. } => None,
2030                TransformBlock::ExcerptFooter { .. } => None,
2031            }
2032        }
2033    }
2034
2035    impl BlockSnapshot {
2036        fn to_point(&self, point: BlockPoint, bias: Bias) -> Point {
2037            self.wrap_snapshot.to_point(self.to_wrap_point(point), bias)
2038        }
2039    }
2040}