block_map.rs

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