block_map.rs

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