fold_map.rs

   1use super::{
   2    buffer::{AnchorRangeExt, TextSummary},
   3    Anchor, Buffer, Point, ToOffset,
   4};
   5use crate::{
   6    editor::buffer,
   7    settings::HighlightId,
   8    sum_tree::{self, Cursor, FilterCursor, SumTree},
   9    time,
  10    util::Bias,
  11};
  12use gpui::{AppContext, ModelHandle};
  13use parking_lot::Mutex;
  14use std::{
  15    cmp::{self, Ordering},
  16    iter, mem,
  17    ops::Range,
  18    sync::atomic::{AtomicUsize, Ordering::SeqCst},
  19};
  20
  21#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
  22pub struct FoldPoint(pub super::Point);
  23
  24impl FoldPoint {
  25    pub fn new(row: u32, column: u32) -> Self {
  26        Self(super::Point::new(row, column))
  27    }
  28
  29    pub fn row(self) -> u32 {
  30        self.0.row
  31    }
  32
  33    pub fn column(self) -> u32 {
  34        self.0.column
  35    }
  36
  37    pub fn row_mut(&mut self) -> &mut u32 {
  38        &mut self.0.row
  39    }
  40
  41    #[cfg(test)]
  42    pub fn column_mut(&mut self) -> &mut u32 {
  43        &mut self.0.column
  44    }
  45
  46    pub fn to_buffer_point(&self, snapshot: &Snapshot) -> Point {
  47        let mut cursor = snapshot.transforms.cursor::<FoldPoint, Point>();
  48        cursor.seek(self, Bias::Right, &());
  49        let overshoot = self.0 - cursor.seek_start().0;
  50        *cursor.sum_start() + overshoot
  51    }
  52
  53    pub fn to_buffer_offset(&self, snapshot: &Snapshot) -> usize {
  54        let mut cursor = snapshot.transforms.cursor::<FoldPoint, Point>();
  55        cursor.seek(self, Bias::Right, &());
  56        let overshoot = self.0 - cursor.seek_start().0;
  57        snapshot
  58            .buffer_snapshot
  59            .to_offset(*cursor.sum_start() + overshoot)
  60    }
  61
  62    pub fn to_offset(&self, snapshot: &Snapshot) -> FoldOffset {
  63        let mut cursor = snapshot.transforms.cursor::<FoldPoint, TransformSummary>();
  64        cursor.seek(self, Bias::Right, &());
  65        let overshoot = self.0 - cursor.sum_start().output.lines;
  66        let mut offset = cursor.sum_start().output.bytes;
  67        if !overshoot.is_zero() {
  68            let transform = cursor.item().expect("display point out of range");
  69            assert!(transform.output_text.is_none());
  70            let end_buffer_offset = snapshot
  71                .buffer_snapshot
  72                .to_offset(cursor.sum_start().input.lines + overshoot);
  73            offset += end_buffer_offset - cursor.sum_start().input.bytes;
  74        }
  75        FoldOffset(offset)
  76    }
  77}
  78
  79impl Point {
  80    pub fn to_fold_point(&self, snapshot: &Snapshot, bias: Bias) -> FoldPoint {
  81        let mut cursor = snapshot.transforms.cursor::<Point, FoldPoint>();
  82        cursor.seek(self, Bias::Right, &());
  83        if cursor.item().map_or(false, |t| t.is_fold()) {
  84            if bias == Bias::Left || *self == *cursor.seek_start() {
  85                *cursor.sum_start()
  86            } else {
  87                cursor.sum_end(&())
  88            }
  89        } else {
  90            let overshoot = *self - cursor.seek_start();
  91            FoldPoint(cmp::min(
  92                cursor.sum_start().0 + overshoot,
  93                cursor.sum_end(&()).0,
  94            ))
  95        }
  96    }
  97}
  98
  99pub struct FoldMapWriter<'a>(&'a mut FoldMap);
 100
 101impl<'a> FoldMapWriter<'a> {
 102    pub fn fold<T: ToOffset>(
 103        &mut self,
 104        ranges: impl IntoIterator<Item = Range<T>>,
 105        cx: &AppContext,
 106    ) -> (Snapshot, Vec<FoldEdit>) {
 107        let mut edits = Vec::new();
 108        let mut folds = Vec::new();
 109        let buffer = self.0.buffer.read(cx).snapshot();
 110        for range in ranges.into_iter() {
 111            let range = range.start.to_offset(&buffer)..range.end.to_offset(&buffer);
 112            if range.start != range.end {
 113                let fold = Fold(buffer.anchor_after(range.start)..buffer.anchor_before(range.end));
 114                folds.push(fold);
 115                edits.push(buffer::Edit {
 116                    old_bytes: range.clone(),
 117                    new_bytes: range.clone(),
 118                    ..Default::default()
 119                });
 120            }
 121        }
 122
 123        folds.sort_unstable_by(|a, b| sum_tree::SeekDimension::cmp(a, b, &buffer));
 124
 125        self.0.folds = {
 126            let mut new_tree = SumTree::new();
 127            let mut cursor = self.0.folds.cursor::<_, ()>();
 128            for fold in folds {
 129                new_tree.push_tree(cursor.slice(&fold, Bias::Right, &buffer), &buffer);
 130                new_tree.push(fold, &buffer);
 131            }
 132            new_tree.push_tree(cursor.suffix(&buffer), &buffer);
 133            new_tree
 134        };
 135
 136        consolidate_buffer_edits(&mut edits);
 137        let edits = self.0.apply_edits(edits, cx);
 138        let snapshot = Snapshot {
 139            transforms: self.0.transforms.lock().clone(),
 140            folds: self.0.folds.clone(),
 141            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 142            version: self.0.version.load(SeqCst),
 143        };
 144        (snapshot, edits)
 145    }
 146
 147    pub fn unfold<T: ToOffset>(
 148        &mut self,
 149        ranges: impl IntoIterator<Item = Range<T>>,
 150        cx: &AppContext,
 151    ) -> (Snapshot, Vec<FoldEdit>) {
 152        let mut edits = Vec::new();
 153        let mut fold_ixs_to_delete = Vec::new();
 154        let buffer = self.0.buffer.read(cx).snapshot();
 155        for range in ranges.into_iter() {
 156            // Remove intersecting folds and add their ranges to edits that are passed to apply_edits.
 157            let mut folds_cursor = intersecting_folds(&buffer, &self.0.folds, range, true);
 158            while let Some(fold) = folds_cursor.item() {
 159                let offset_range = fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer);
 160                edits.push(buffer::Edit {
 161                    old_bytes: offset_range.clone(),
 162                    new_bytes: offset_range,
 163                    ..Default::default()
 164                });
 165                fold_ixs_to_delete.push(*folds_cursor.start());
 166                folds_cursor.next(&buffer);
 167            }
 168        }
 169
 170        fold_ixs_to_delete.sort_unstable();
 171        fold_ixs_to_delete.dedup();
 172
 173        self.0.folds = {
 174            let mut cursor = self.0.folds.cursor::<_, ()>();
 175            let mut folds = SumTree::new();
 176            for fold_ix in fold_ixs_to_delete {
 177                folds.push_tree(cursor.slice(&fold_ix, Bias::Right, &buffer), &buffer);
 178                cursor.next(&buffer);
 179            }
 180            folds.push_tree(cursor.suffix(&buffer), &buffer);
 181            folds
 182        };
 183
 184        consolidate_buffer_edits(&mut edits);
 185        let edits = self.0.apply_edits(edits, cx);
 186        let snapshot = Snapshot {
 187            transforms: self.0.transforms.lock().clone(),
 188            folds: self.0.folds.clone(),
 189            buffer_snapshot: self.0.buffer.read(cx).snapshot(),
 190            version: self.0.version.load(SeqCst),
 191        };
 192        (snapshot, edits)
 193    }
 194}
 195
 196pub struct FoldMap {
 197    buffer: ModelHandle<Buffer>,
 198    transforms: Mutex<SumTree<Transform>>,
 199    folds: SumTree<Fold>,
 200    last_sync: Mutex<SyncState>,
 201    version: AtomicUsize,
 202}
 203
 204#[derive(Clone)]
 205struct SyncState {
 206    version: time::Global,
 207    is_parsing: bool,
 208}
 209
 210impl FoldMap {
 211    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
 212        let buffer = buffer_handle.read(cx);
 213        let this = Self {
 214            buffer: buffer_handle,
 215            folds: Default::default(),
 216            transforms: Mutex::new(SumTree::from_item(
 217                Transform {
 218                    summary: TransformSummary {
 219                        input: buffer.text_summary(),
 220                        output: buffer.text_summary(),
 221                    },
 222                    output_text: None,
 223                },
 224                &(),
 225            )),
 226            last_sync: Mutex::new(SyncState {
 227                version: buffer.version(),
 228                is_parsing: buffer.is_parsing(),
 229            }),
 230            version: AtomicUsize::new(0),
 231        };
 232        let (snapshot, _) = this.read(cx);
 233        (this, snapshot)
 234    }
 235
 236    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<FoldEdit>) {
 237        let edits = self.sync(cx);
 238        self.check_invariants(cx);
 239        let snapshot = Snapshot {
 240            transforms: self.transforms.lock().clone(),
 241            folds: self.folds.clone(),
 242            buffer_snapshot: self.buffer.read(cx).snapshot(),
 243            version: self.version.load(SeqCst),
 244        };
 245        (snapshot, edits)
 246    }
 247
 248    pub fn write(&mut self, cx: &AppContext) -> (FoldMapWriter, Snapshot, Vec<FoldEdit>) {
 249        let (snapshot, edits) = self.read(cx);
 250        (FoldMapWriter(self), snapshot, edits)
 251    }
 252
 253    fn sync(&self, cx: &AppContext) -> Vec<FoldEdit> {
 254        let buffer = self.buffer.read(cx);
 255        let last_sync = mem::replace(
 256            &mut *self.last_sync.lock(),
 257            SyncState {
 258                version: buffer.version(),
 259                is_parsing: buffer.is_parsing(),
 260            },
 261        );
 262        let edits = buffer
 263            .edits_since(last_sync.version)
 264            .map(Into::into)
 265            .collect::<Vec<_>>();
 266        if edits.is_empty() {
 267            if last_sync.is_parsing != buffer.is_parsing() {
 268                self.version.fetch_add(1, SeqCst);
 269            }
 270            Vec::new()
 271        } else {
 272            self.apply_edits(edits, cx)
 273        }
 274    }
 275
 276    fn check_invariants(&self, cx: &AppContext) {
 277        if cfg!(test) {
 278            let buffer = self.buffer.read(cx);
 279            assert_eq!(
 280                self.transforms.lock().summary().input.bytes,
 281                buffer.len(),
 282                "transform tree does not match buffer's length"
 283            );
 284        }
 285    }
 286
 287    fn apply_edits(&self, buffer_edits: Vec<buffer::Edit>, cx: &AppContext) -> Vec<FoldEdit> {
 288        let buffer = self.buffer.read(cx).snapshot();
 289        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
 290
 291        let mut new_transforms = SumTree::new();
 292        let mut transforms = self.transforms.lock();
 293        let mut cursor = transforms.cursor::<usize, ()>();
 294        cursor.seek(&0, Bias::Right, &());
 295
 296        while let Some(mut edit) = buffer_edits_iter.next() {
 297            new_transforms.push_tree(cursor.slice(&edit.old_bytes.start, Bias::Left, &()), &());
 298            edit.new_bytes.start -= edit.old_bytes.start - cursor.seek_start();
 299            edit.old_bytes.start = *cursor.seek_start();
 300
 301            cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 302            cursor.next(&());
 303
 304            let mut delta = edit.delta();
 305            loop {
 306                edit.old_bytes.end = *cursor.seek_start();
 307
 308                if let Some(next_edit) = buffer_edits_iter.peek() {
 309                    if next_edit.old_bytes.start > edit.old_bytes.end {
 310                        break;
 311                    }
 312
 313                    let next_edit = buffer_edits_iter.next().unwrap();
 314                    delta += next_edit.delta();
 315
 316                    if next_edit.old_bytes.end >= edit.old_bytes.end {
 317                        edit.old_bytes.end = next_edit.old_bytes.end;
 318                        cursor.seek(&edit.old_bytes.end, Bias::Right, &());
 319                        cursor.next(&());
 320                    }
 321                } else {
 322                    break;
 323                }
 324            }
 325
 326            edit.new_bytes.end =
 327                ((edit.new_bytes.start + edit.deleted_bytes()) as isize + delta) as usize;
 328
 329            let anchor = buffer.anchor_before(edit.new_bytes.start);
 330            let mut folds_cursor = self.folds.cursor::<_, ()>();
 331            folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
 332
 333            let mut folds = iter::from_fn({
 334                let buffer = &buffer;
 335                move || {
 336                    let item = folds_cursor
 337                        .item()
 338                        .map(|f| f.0.start.to_offset(buffer)..f.0.end.to_offset(buffer));
 339                    folds_cursor.next(buffer);
 340                    item
 341                }
 342            })
 343            .peekable();
 344
 345            while folds
 346                .peek()
 347                .map_or(false, |fold| fold.start < edit.new_bytes.end)
 348            {
 349                let mut fold = folds.next().unwrap();
 350                let sum = new_transforms.summary();
 351
 352                assert!(fold.start >= sum.input.bytes);
 353
 354                while folds
 355                    .peek()
 356                    .map_or(false, |next_fold| next_fold.start <= fold.end)
 357                {
 358                    let next_fold = folds.next().unwrap();
 359                    if next_fold.end > fold.end {
 360                        fold.end = next_fold.end;
 361                    }
 362                }
 363
 364                if fold.start > sum.input.bytes {
 365                    let text_summary = buffer.text_summary_for_range(sum.input.bytes..fold.start);
 366                    new_transforms.push(
 367                        Transform {
 368                            summary: TransformSummary {
 369                                output: text_summary.clone(),
 370                                input: text_summary,
 371                            },
 372                            output_text: None,
 373                        },
 374                        &(),
 375                    );
 376                }
 377
 378                if fold.end > fold.start {
 379                    let output_text = "";
 380                    let chars = output_text.chars().count() as u32;
 381                    let lines = super::Point::new(0, output_text.len() as u32);
 382                    new_transforms.push(
 383                        Transform {
 384                            summary: TransformSummary {
 385                                output: TextSummary {
 386                                    bytes: output_text.len(),
 387                                    lines,
 388                                    first_line_chars: chars,
 389                                    last_line_chars: chars,
 390                                    longest_row: 0,
 391                                    longest_row_chars: chars,
 392                                },
 393                                input: buffer.text_summary_for_range(fold.start..fold.end),
 394                            },
 395                            output_text: Some(output_text),
 396                        },
 397                        &(),
 398                    );
 399                }
 400            }
 401
 402            let sum = new_transforms.summary();
 403            if sum.input.bytes < edit.new_bytes.end {
 404                let text_summary =
 405                    buffer.text_summary_for_range(sum.input.bytes..edit.new_bytes.end);
 406                new_transforms.push(
 407                    Transform {
 408                        summary: TransformSummary {
 409                            output: text_summary.clone(),
 410                            input: text_summary,
 411                        },
 412                        output_text: None,
 413                    },
 414                    &(),
 415                );
 416            }
 417        }
 418
 419        new_transforms.push_tree(cursor.suffix(&()), &());
 420        if new_transforms.is_empty() {
 421            let text_summary = buffer.text_summary();
 422            new_transforms.push(
 423                Transform {
 424                    summary: TransformSummary {
 425                        output: text_summary.clone(),
 426                        input: text_summary,
 427                    },
 428                    output_text: None,
 429                },
 430                &(),
 431            );
 432        }
 433
 434        drop(cursor);
 435
 436        let mut fold_edits = Vec::with_capacity(buffer_edits.len());
 437        {
 438            let mut old_transforms = transforms.cursor::<usize, FoldOffset>();
 439            let mut new_transforms = new_transforms.cursor::<usize, FoldOffset>();
 440
 441            for mut edit in buffer_edits {
 442                old_transforms.seek(&edit.old_bytes.start, Bias::Left, &());
 443                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 444                    edit.old_bytes.start = *old_transforms.seek_start();
 445                }
 446                let old_start = old_transforms.sum_start().0
 447                    + (edit.old_bytes.start - old_transforms.seek_start());
 448
 449                old_transforms.seek_forward(&edit.old_bytes.end, Bias::Right, &());
 450                if old_transforms.item().map_or(false, |t| t.is_fold()) {
 451                    old_transforms.next(&());
 452                    edit.old_bytes.end = *old_transforms.seek_start();
 453                }
 454                let old_end = old_transforms.sum_start().0
 455                    + (edit.old_bytes.end - old_transforms.seek_start());
 456
 457                new_transforms.seek(&edit.new_bytes.start, Bias::Left, &());
 458                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 459                    edit.new_bytes.start = *new_transforms.seek_start();
 460                }
 461                let new_start = new_transforms.sum_start().0
 462                    + (edit.new_bytes.start - new_transforms.seek_start());
 463
 464                new_transforms.seek_forward(&edit.new_bytes.end, Bias::Right, &());
 465                if new_transforms.item().map_or(false, |t| t.is_fold()) {
 466                    new_transforms.next(&());
 467                    edit.new_bytes.end = *new_transforms.seek_start();
 468                }
 469                let new_end = new_transforms.sum_start().0
 470                    + (edit.new_bytes.end - new_transforms.seek_start());
 471
 472                fold_edits.push(FoldEdit {
 473                    old_bytes: FoldOffset(old_start)..FoldOffset(old_end),
 474                    new_bytes: FoldOffset(new_start)..FoldOffset(new_end),
 475                });
 476            }
 477
 478            consolidate_fold_edits(&mut fold_edits);
 479        }
 480
 481        *transforms = new_transforms;
 482        self.version.fetch_add(1, SeqCst);
 483        fold_edits
 484    }
 485}
 486
 487#[derive(Clone)]
 488pub struct Snapshot {
 489    transforms: SumTree<Transform>,
 490    folds: SumTree<Fold>,
 491    buffer_snapshot: buffer::Snapshot,
 492    pub version: usize,
 493}
 494
 495impl Snapshot {
 496    #[cfg(test)]
 497    pub fn text(&self) -> String {
 498        self.chunks_at(FoldOffset(0)).collect()
 499    }
 500
 501    #[cfg(test)]
 502    pub fn fold_count(&self) -> usize {
 503        self.folds.items(&self.buffer_snapshot).len()
 504    }
 505
 506    pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
 507        let mut summary = TextSummary::default();
 508
 509        let mut cursor = self.transforms.cursor::<FoldPoint, Point>();
 510        cursor.seek(&range.start, Bias::Right, &());
 511        if let Some(transform) = cursor.item() {
 512            let start_in_transform = range.start.0 - cursor.seek_start().0;
 513            let end_in_transform =
 514                cmp::min(range.end, cursor.seek_end(&())).0 - cursor.seek_start().0;
 515            if let Some(output_text) = transform.output_text {
 516                summary = TextSummary::from(
 517                    &output_text
 518                        [start_in_transform.column as usize..end_in_transform.column as usize],
 519                );
 520            } else {
 521                let buffer_start = *cursor.sum_start() + start_in_transform;
 522                let buffer_end = *cursor.sum_start() + end_in_transform;
 523                summary = self
 524                    .buffer_snapshot
 525                    .text_summary_for_range(buffer_start..buffer_end);
 526            }
 527        }
 528
 529        if range.end > cursor.seek_end(&()) {
 530            cursor.next(&());
 531            summary += &cursor
 532                .summary::<TransformSummary>(&range.end, Bias::Right, &())
 533                .output;
 534            if let Some(transform) = cursor.item() {
 535                let end_in_transform = range.end.0 - cursor.seek_start().0;
 536                if let Some(output_text) = transform.output_text {
 537                    summary += TextSummary::from(&output_text[..end_in_transform.column as usize]);
 538                } else {
 539                    let buffer_start = *cursor.sum_start();
 540                    let buffer_end = *cursor.sum_start() + end_in_transform;
 541                    summary += self
 542                        .buffer_snapshot
 543                        .text_summary_for_range(buffer_start..buffer_end);
 544                }
 545            }
 546        }
 547
 548        summary
 549    }
 550
 551    pub fn len(&self) -> FoldOffset {
 552        FoldOffset(self.transforms.summary().output.bytes)
 553    }
 554
 555    #[cfg(test)]
 556    pub fn line_len(&self, row: u32) -> u32 {
 557        let line_start = FoldPoint::new(row, 0).to_offset(self).0;
 558        let line_end = if row >= self.max_point().row() {
 559            self.len().0
 560        } else {
 561            FoldPoint::new(row + 1, 0).to_offset(self).0 - 1
 562        };
 563        (line_end - line_start) as u32
 564    }
 565
 566    pub fn buffer_rows(&self, start_row: u32) -> BufferRows {
 567        if start_row > self.transforms.summary().output.lines.row {
 568            panic!("invalid display row {}", start_row);
 569        }
 570
 571        let fold_point = FoldPoint::new(start_row, 0);
 572        let mut cursor = self.transforms.cursor();
 573        cursor.seek(&fold_point, Bias::Left, &());
 574        BufferRows { fold_point, cursor }
 575    }
 576
 577    pub fn max_point(&self) -> FoldPoint {
 578        FoldPoint(self.transforms.summary().output.lines)
 579    }
 580
 581    #[cfg(test)]
 582    pub fn longest_row(&self) -> u32 {
 583        self.transforms.summary().output.longest_row
 584    }
 585
 586    pub fn folds_in_range<'a, T>(
 587        &'a self,
 588        range: Range<T>,
 589    ) -> impl Iterator<Item = &'a Range<Anchor>>
 590    where
 591        T: ToOffset,
 592    {
 593        let mut folds = intersecting_folds(&self.buffer_snapshot, &self.folds, range, false);
 594        iter::from_fn(move || {
 595            let item = folds.item().map(|f| &f.0);
 596            folds.next(&self.buffer_snapshot);
 597            item
 598        })
 599    }
 600
 601    pub fn intersects_fold<T>(&self, offset: T) -> bool
 602    where
 603        T: ToOffset,
 604    {
 605        let offset = offset.to_offset(&self.buffer_snapshot);
 606        let mut cursor = self.transforms.cursor::<usize, ()>();
 607        cursor.seek(&offset, Bias::Right, &());
 608        cursor.item().map_or(false, |t| t.output_text.is_some())
 609    }
 610
 611    pub fn is_line_folded(&self, output_row: u32) -> bool {
 612        let mut cursor = self.transforms.cursor::<FoldPoint, ()>();
 613        cursor.seek(&FoldPoint::new(output_row, 0), Bias::Right, &());
 614        while let Some(transform) = cursor.item() {
 615            if transform.output_text.is_some() {
 616                return true;
 617            }
 618            if cursor.seek_end(&()).row() == output_row {
 619                cursor.next(&())
 620            } else {
 621                break;
 622            }
 623        }
 624        false
 625    }
 626
 627    pub fn chunks_at(&self, offset: FoldOffset) -> Chunks {
 628        let mut transform_cursor = self.transforms.cursor::<FoldOffset, usize>();
 629        transform_cursor.seek(&offset, Bias::Right, &());
 630        let overshoot = offset.0 - transform_cursor.seek_start().0;
 631        let buffer_offset = transform_cursor.sum_start() + overshoot;
 632        Chunks {
 633            transform_cursor,
 634            buffer_offset,
 635            buffer_chunks: self
 636                .buffer_snapshot
 637                .text_for_range(buffer_offset..self.buffer_snapshot.len()),
 638        }
 639    }
 640
 641    pub fn highlighted_chunks(&mut self, range: Range<FoldOffset>) -> HighlightedChunks {
 642        let mut transform_cursor = self.transforms.cursor::<FoldOffset, usize>();
 643
 644        transform_cursor.seek(&range.end, Bias::Right, &());
 645        let overshoot = range.end.0 - transform_cursor.seek_start().0;
 646        let buffer_end = transform_cursor.sum_start() + overshoot;
 647
 648        transform_cursor.seek(&range.start, Bias::Right, &());
 649        let overshoot = range.start.0 - transform_cursor.seek_start().0;
 650        let buffer_start = transform_cursor.sum_start() + overshoot;
 651
 652        HighlightedChunks {
 653            transform_cursor,
 654            buffer_offset: buffer_start,
 655            buffer_chunks: self
 656                .buffer_snapshot
 657                .highlighted_text_for_range(buffer_start..buffer_end),
 658            buffer_chunk: None,
 659        }
 660    }
 661
 662    pub fn chars_at<'a>(&'a self, point: FoldPoint) -> impl Iterator<Item = char> + 'a {
 663        let offset = point.to_offset(self);
 664        self.chunks_at(offset).flat_map(str::chars)
 665    }
 666
 667    #[cfg(test)]
 668    pub fn clip_offset(&self, offset: FoldOffset, bias: Bias) -> FoldOffset {
 669        let mut cursor = self.transforms.cursor::<FoldOffset, usize>();
 670        cursor.seek(&offset, Bias::Right, &());
 671        if let Some(transform) = cursor.item() {
 672            let transform_start = cursor.seek_start().0;
 673            if transform.output_text.is_some() {
 674                if offset.0 == transform_start || matches!(bias, Bias::Left) {
 675                    FoldOffset(transform_start)
 676                } else {
 677                    FoldOffset(cursor.seek_end(&()).0)
 678                }
 679            } else {
 680                let overshoot = offset.0 - transform_start;
 681                let buffer_offset = cursor.sum_start() + overshoot;
 682                let clipped_buffer_offset = self.buffer_snapshot.clip_offset(buffer_offset, bias);
 683                FoldOffset(
 684                    (offset.0 as isize + (clipped_buffer_offset as isize - buffer_offset as isize))
 685                        as usize,
 686                )
 687            }
 688        } else {
 689            FoldOffset(self.transforms.summary().output.bytes)
 690        }
 691    }
 692
 693    pub fn clip_point(&self, point: FoldPoint, bias: Bias) -> FoldPoint {
 694        let mut cursor = self.transforms.cursor::<FoldPoint, Point>();
 695        cursor.seek(&point, Bias::Right, &());
 696        if let Some(transform) = cursor.item() {
 697            let transform_start = cursor.seek_start().0;
 698            if transform.output_text.is_some() {
 699                if point.0 == transform_start || matches!(bias, Bias::Left) {
 700                    FoldPoint(transform_start)
 701                } else {
 702                    FoldPoint(cursor.seek_end(&()).0)
 703                }
 704            } else {
 705                let overshoot = point.0 - transform_start;
 706                let buffer_position = *cursor.sum_start() + overshoot;
 707                let clipped_buffer_position =
 708                    self.buffer_snapshot.clip_point(buffer_position, bias);
 709                FoldPoint::new(
 710                    point.row(),
 711                    ((point.column() as i32) + clipped_buffer_position.column as i32
 712                        - buffer_position.column as i32) as u32,
 713                )
 714            }
 715        } else {
 716            FoldPoint(self.transforms.summary().output.lines)
 717        }
 718    }
 719}
 720
 721fn intersecting_folds<'a, T>(
 722    buffer: &'a buffer::Snapshot,
 723    folds: &'a SumTree<Fold>,
 724    range: Range<T>,
 725    inclusive: bool,
 726) -> FilterCursor<'a, impl 'a + Fn(&FoldSummary) -> bool, Fold, usize>
 727where
 728    T: ToOffset,
 729{
 730    let start = buffer.anchor_before(range.start.to_offset(buffer));
 731    let end = buffer.anchor_after(range.end.to_offset(buffer));
 732    folds.filter::<_, usize>(
 733        move |summary| {
 734            let start_cmp = start.cmp(&summary.max_end, buffer).unwrap();
 735            let end_cmp = end.cmp(&summary.min_start, buffer).unwrap();
 736
 737            if inclusive {
 738                start_cmp <= Ordering::Equal && end_cmp >= Ordering::Equal
 739            } else {
 740                start_cmp == Ordering::Less && end_cmp == Ordering::Greater
 741            }
 742        },
 743        buffer,
 744    )
 745}
 746
 747fn consolidate_buffer_edits(edits: &mut Vec<buffer::Edit>) {
 748    edits.sort_unstable_by(|a, b| {
 749        a.old_bytes
 750            .start
 751            .cmp(&b.old_bytes.start)
 752            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 753    });
 754
 755    let mut i = 1;
 756    while i < edits.len() {
 757        let edit = edits[i].clone();
 758        let prev_edit = &mut edits[i - 1];
 759        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 760            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 761            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 762            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 763            edits.remove(i);
 764            continue;
 765        }
 766        i += 1;
 767    }
 768}
 769
 770fn consolidate_fold_edits(edits: &mut Vec<FoldEdit>) {
 771    edits.sort_unstable_by(|a, b| {
 772        a.old_bytes
 773            .start
 774            .cmp(&b.old_bytes.start)
 775            .then_with(|| b.old_bytes.end.cmp(&a.old_bytes.end))
 776    });
 777
 778    let mut i = 1;
 779    while i < edits.len() {
 780        let edit = edits[i].clone();
 781        let prev_edit = &mut edits[i - 1];
 782        if prev_edit.old_bytes.end >= edit.old_bytes.start {
 783            prev_edit.old_bytes.end = prev_edit.old_bytes.end.max(edit.old_bytes.end);
 784            prev_edit.new_bytes.start = prev_edit.new_bytes.start.min(edit.new_bytes.start);
 785            prev_edit.new_bytes.end = prev_edit.new_bytes.end.max(edit.new_bytes.end);
 786            edits.remove(i);
 787            continue;
 788        }
 789        i += 1;
 790    }
 791}
 792
 793#[derive(Clone, Debug, Default, Eq, PartialEq)]
 794struct Transform {
 795    summary: TransformSummary,
 796    output_text: Option<&'static str>,
 797}
 798
 799impl Transform {
 800    fn is_fold(&self) -> bool {
 801        self.output_text.is_some()
 802    }
 803}
 804
 805#[derive(Clone, Debug, Default, Eq, PartialEq)]
 806struct TransformSummary {
 807    output: TextSummary,
 808    input: TextSummary,
 809}
 810
 811impl sum_tree::Item for Transform {
 812    type Summary = TransformSummary;
 813
 814    fn summary(&self) -> Self::Summary {
 815        self.summary.clone()
 816    }
 817}
 818
 819impl sum_tree::Summary for TransformSummary {
 820    type Context = ();
 821
 822    fn add_summary(&mut self, other: &Self, _: &()) {
 823        self.input += &other.input;
 824        self.output += &other.output;
 825    }
 826}
 827
 828impl<'a> sum_tree::Dimension<'a, TransformSummary> for TransformSummary {
 829    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
 830        sum_tree::Summary::add_summary(self, summary, &());
 831    }
 832}
 833
 834#[derive(Clone, Debug)]
 835struct Fold(Range<Anchor>);
 836
 837impl Default for Fold {
 838    fn default() -> Self {
 839        Self(Anchor::min()..Anchor::max())
 840    }
 841}
 842
 843impl sum_tree::Item for Fold {
 844    type Summary = FoldSummary;
 845
 846    fn summary(&self) -> Self::Summary {
 847        FoldSummary {
 848            start: self.0.start.clone(),
 849            end: self.0.end.clone(),
 850            min_start: self.0.start.clone(),
 851            max_end: self.0.end.clone(),
 852            count: 1,
 853        }
 854    }
 855}
 856
 857#[derive(Clone, Debug)]
 858struct FoldSummary {
 859    start: Anchor,
 860    end: Anchor,
 861    min_start: Anchor,
 862    max_end: Anchor,
 863    count: usize,
 864}
 865
 866impl Default for FoldSummary {
 867    fn default() -> Self {
 868        Self {
 869            start: Anchor::min(),
 870            end: Anchor::max(),
 871            min_start: Anchor::max(),
 872            max_end: Anchor::min(),
 873            count: 0,
 874        }
 875    }
 876}
 877
 878impl sum_tree::Summary for FoldSummary {
 879    type Context = buffer::Snapshot;
 880
 881    fn add_summary(&mut self, other: &Self, buffer: &buffer::Snapshot) {
 882        if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
 883            self.min_start = other.min_start.clone();
 884        }
 885        if other.max_end.cmp(&self.max_end, buffer).unwrap() == Ordering::Greater {
 886            self.max_end = other.max_end.clone();
 887        }
 888
 889        #[cfg(debug_assertions)]
 890        {
 891            let start_comparison = self.start.cmp(&other.start, buffer).unwrap();
 892            assert!(start_comparison <= Ordering::Equal);
 893            if start_comparison == Ordering::Equal {
 894                assert!(self.end.cmp(&other.end, buffer).unwrap() >= Ordering::Equal);
 895            }
 896        }
 897
 898        self.start = other.start.clone();
 899        self.end = other.end.clone();
 900        self.count += other.count;
 901    }
 902}
 903
 904impl<'a> sum_tree::Dimension<'a, FoldSummary> for Fold {
 905    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 906        self.0.start = summary.start.clone();
 907        self.0.end = summary.end.clone();
 908    }
 909}
 910
 911impl<'a> sum_tree::SeekDimension<'a, FoldSummary> for Fold {
 912    fn cmp(&self, other: &Self, buffer: &buffer::Snapshot) -> Ordering {
 913        self.0.cmp(&other.0, buffer).unwrap()
 914    }
 915}
 916
 917impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 918    fn add_summary(&mut self, summary: &'a FoldSummary, _: &buffer::Snapshot) {
 919        *self += summary.count;
 920    }
 921}
 922
 923pub struct BufferRows<'a> {
 924    cursor: Cursor<'a, Transform, FoldPoint, Point>,
 925    fold_point: FoldPoint,
 926}
 927
 928impl<'a> Iterator for BufferRows<'a> {
 929    type Item = u32;
 930
 931    fn next(&mut self) -> Option<Self::Item> {
 932        while self.fold_point > self.cursor.seek_end(&()) {
 933            self.cursor.next(&());
 934            if self.cursor.item().is_none() {
 935                // TODO: Return a bool from next?
 936                break;
 937            }
 938        }
 939
 940        if self.cursor.item().is_some() {
 941            let overshoot = self.fold_point.0 - self.cursor.seek_start().0;
 942            let buffer_point = *self.cursor.sum_start() + overshoot;
 943            *self.fold_point.row_mut() += 1;
 944            Some(buffer_point.row)
 945        } else {
 946            None
 947        }
 948    }
 949}
 950
 951pub struct Chunks<'a> {
 952    transform_cursor: Cursor<'a, Transform, FoldOffset, usize>,
 953    buffer_chunks: buffer::Chunks<'a>,
 954    buffer_offset: usize,
 955}
 956
 957impl<'a> Iterator for Chunks<'a> {
 958    type Item = &'a str;
 959
 960    fn next(&mut self) -> Option<Self::Item> {
 961        let transform = if let Some(item) = self.transform_cursor.item() {
 962            item
 963        } else {
 964            return None;
 965        };
 966
 967        // If we're in a fold, then return the fold's display text and
 968        // advance the transform and buffer cursors to the end of the fold.
 969        if let Some(output_text) = transform.output_text {
 970            self.buffer_offset += transform.summary.input.bytes;
 971            self.buffer_chunks.seek(self.buffer_offset);
 972
 973            while self.buffer_offset >= self.transform_cursor.sum_end(&())
 974                && self.transform_cursor.item().is_some()
 975            {
 976                self.transform_cursor.next(&());
 977            }
 978
 979            return Some(output_text);
 980        }
 981
 982        // Otherwise, take a chunk from the buffer's text.
 983        if let Some(mut chunk) = self.buffer_chunks.peek() {
 984            let offset_in_chunk = self.buffer_offset - self.buffer_chunks.offset();
 985            chunk = &chunk[offset_in_chunk..];
 986
 987            // Truncate the chunk so that it ends at the next fold.
 988            let region_end = self.transform_cursor.sum_end(&()) - self.buffer_offset;
 989            if chunk.len() >= region_end {
 990                chunk = &chunk[0..region_end];
 991                self.transform_cursor.next(&());
 992            } else {
 993                self.buffer_chunks.next();
 994            }
 995
 996            self.buffer_offset += chunk.len();
 997            return Some(chunk);
 998        }
 999
1000        None
1001    }
1002}
1003
1004pub struct HighlightedChunks<'a> {
1005    transform_cursor: Cursor<'a, Transform, FoldOffset, usize>,
1006    buffer_chunks: buffer::HighlightedChunks<'a>,
1007    buffer_chunk: Option<(usize, &'a str, HighlightId)>,
1008    buffer_offset: usize,
1009}
1010
1011impl<'a> Iterator for HighlightedChunks<'a> {
1012    type Item = (&'a str, HighlightId);
1013
1014    fn next(&mut self) -> Option<Self::Item> {
1015        let transform = if let Some(item) = self.transform_cursor.item() {
1016            item
1017        } else {
1018            return None;
1019        };
1020
1021        // If we're in a fold, then return the fold's display text and
1022        // advance the transform and buffer cursors to the end of the fold.
1023        if let Some(output_text) = transform.output_text {
1024            self.buffer_chunk.take();
1025            self.buffer_offset += transform.summary.input.bytes;
1026            self.buffer_chunks.seek(self.buffer_offset);
1027
1028            while self.buffer_offset >= self.transform_cursor.sum_end(&())
1029                && self.transform_cursor.item().is_some()
1030            {
1031                self.transform_cursor.next(&());
1032            }
1033
1034            return Some((output_text, HighlightId::default()));
1035        }
1036
1037        // Retrieve a chunk from the current location in the buffer.
1038        if self.buffer_chunk.is_none() {
1039            let chunk_offset = self.buffer_chunks.offset();
1040            self.buffer_chunk = self
1041                .buffer_chunks
1042                .next()
1043                .map(|(chunk, capture_ix)| (chunk_offset, chunk, capture_ix));
1044        }
1045
1046        // Otherwise, take a chunk from the buffer's text.
1047        if let Some((chunk_offset, mut chunk, capture_ix)) = self.buffer_chunk {
1048            let offset_in_chunk = self.buffer_offset - chunk_offset;
1049            chunk = &chunk[offset_in_chunk..];
1050
1051            // Truncate the chunk so that it ends at the next fold.
1052            let region_end = self.transform_cursor.sum_end(&()) - self.buffer_offset;
1053            if chunk.len() >= region_end {
1054                chunk = &chunk[0..region_end];
1055                self.transform_cursor.next(&());
1056            } else {
1057                self.buffer_chunk.take();
1058            }
1059
1060            self.buffer_offset += chunk.len();
1061            return Some((chunk, capture_ix));
1062        }
1063
1064        None
1065    }
1066}
1067
1068impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldPoint {
1069    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1070        self.0 += &summary.output.lines;
1071    }
1072}
1073
1074#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
1075pub struct FoldOffset(pub usize);
1076
1077impl FoldOffset {
1078    pub fn to_point(&self, snapshot: &Snapshot) -> FoldPoint {
1079        let mut cursor = snapshot.transforms.cursor::<FoldOffset, TransformSummary>();
1080        cursor.seek(self, Bias::Right, &());
1081        let overshoot = if cursor.item().map_or(true, |t| t.is_fold()) {
1082            Point::new(0, (self.0 - cursor.seek_start().0) as u32)
1083        } else {
1084            let buffer_offset = cursor.sum_start().input.bytes + self.0 - cursor.seek_start().0;
1085            let buffer_point = snapshot.buffer_snapshot.to_point(buffer_offset);
1086            buffer_point - cursor.sum_start().input.lines
1087        };
1088        FoldPoint(cursor.sum_start().output.lines + overshoot)
1089    }
1090}
1091
1092impl<'a> sum_tree::Dimension<'a, TransformSummary> for FoldOffset {
1093    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1094        self.0 += &summary.output.bytes;
1095    }
1096}
1097
1098impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
1099    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1100        *self += &summary.input.lines;
1101    }
1102}
1103
1104impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
1105    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
1106        *self += &summary.input.bytes;
1107    }
1108}
1109
1110#[derive(Clone, Debug, PartialEq, Eq)]
1111pub struct FoldEdit {
1112    pub old_bytes: Range<FoldOffset>,
1113    pub new_bytes: Range<FoldOffset>,
1114}
1115
1116#[cfg(test)]
1117impl FoldEdit {
1118    pub fn delta(&self) -> isize {
1119        self.inserted_bytes() as isize - self.deleted_bytes() as isize
1120    }
1121
1122    pub fn deleted_bytes(&self) -> usize {
1123        self.old_bytes.end.0 - self.old_bytes.start.0
1124    }
1125
1126    pub fn inserted_bytes(&self) -> usize {
1127        self.new_bytes.end.0 - self.new_bytes.start.0
1128    }
1129}
1130
1131#[cfg(test)]
1132mod tests {
1133    use super::*;
1134    use crate::{editor::ToPoint, test::sample_text, util::RandomCharIter};
1135    use rand::prelude::*;
1136    use std::{env, mem};
1137    use Bias::{Left, Right};
1138
1139    #[gpui::test]
1140    fn test_basic_folds(cx: &mut gpui::MutableAppContext) {
1141        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1142        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1143
1144        let (mut writer, _, _) = map.write(cx.as_ref());
1145        let (snapshot2, edits) = writer.fold(
1146            vec![
1147                Point::new(0, 2)..Point::new(2, 2),
1148                Point::new(2, 4)..Point::new(4, 1),
1149            ],
1150            cx.as_ref(),
1151        );
1152        assert_eq!(snapshot2.text(), "aa…cc…eeeee");
1153        assert_eq!(
1154            edits,
1155            &[
1156                FoldEdit {
1157                    old_bytes: FoldOffset(2)..FoldOffset(16),
1158                    new_bytes: FoldOffset(2)..FoldOffset(5),
1159                },
1160                FoldEdit {
1161                    old_bytes: FoldOffset(18)..FoldOffset(29),
1162                    new_bytes: FoldOffset(7)..FoldOffset(10)
1163                },
1164            ]
1165        );
1166
1167        buffer.update(cx, |buffer, cx| {
1168            buffer.edit(
1169                vec![
1170                    Point::new(0, 0)..Point::new(0, 1),
1171                    Point::new(2, 3)..Point::new(2, 3),
1172                ],
1173                "123",
1174                cx,
1175            );
1176        });
1177        let (snapshot3, edits) = map.read(cx.as_ref());
1178        assert_eq!(snapshot3.text(), "123a…c123c…eeeee");
1179        assert_eq!(
1180            edits,
1181            &[
1182                FoldEdit {
1183                    old_bytes: FoldOffset(0)..FoldOffset(1),
1184                    new_bytes: FoldOffset(0)..FoldOffset(3),
1185                },
1186                FoldEdit {
1187                    old_bytes: FoldOffset(6)..FoldOffset(6),
1188                    new_bytes: FoldOffset(8)..FoldOffset(11),
1189                },
1190            ]
1191        );
1192
1193        buffer.update(cx, |buffer, cx| {
1194            buffer.edit(vec![Point::new(2, 6)..Point::new(4, 3)], "456", cx)
1195        });
1196        let (snapshot4, _) = map.read(cx.as_ref());
1197        assert_eq!(snapshot4.text(), "123a…c123456eee");
1198
1199        let (mut writer, _, _) = map.write(cx.as_ref());
1200        writer.unfold(Some(Point::new(0, 4)..Point::new(0, 5)), cx.as_ref());
1201        let (snapshot5, _) = map.read(cx.as_ref());
1202        assert_eq!(snapshot5.text(), "123aaaaa\nbbbbbb\nccc123456eee");
1203    }
1204
1205    #[gpui::test]
1206    fn test_adjacent_folds(cx: &mut gpui::MutableAppContext) {
1207        let buffer = cx.add_model(|cx| Buffer::new(0, "abcdefghijkl", cx));
1208
1209        {
1210            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1211
1212            let (mut writer, _, _) = map.write(cx.as_ref());
1213            writer.fold(vec![5..8], cx.as_ref());
1214            let (snapshot, _) = map.read(cx.as_ref());
1215            assert_eq!(snapshot.text(), "abcde…ijkl");
1216
1217            // Create an fold adjacent to the start of the first fold.
1218            let (mut writer, _, _) = map.write(cx.as_ref());
1219            writer.fold(vec![0..1, 2..5], cx.as_ref());
1220            let (snapshot, _) = map.read(cx.as_ref());
1221            assert_eq!(snapshot.text(), "…b…ijkl");
1222
1223            // Create an fold adjacent to the end of the first fold.
1224            let (mut writer, _, _) = map.write(cx.as_ref());
1225            writer.fold(vec![11..11, 8..10], cx.as_ref());
1226            let (snapshot, _) = map.read(cx.as_ref());
1227            assert_eq!(snapshot.text(), "…b…kl");
1228        }
1229
1230        {
1231            let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1232
1233            // Create two adjacent folds.
1234            let (mut writer, _, _) = map.write(cx.as_ref());
1235            writer.fold(vec![0..2, 2..5], cx.as_ref());
1236            let (snapshot, _) = map.read(cx.as_ref());
1237            assert_eq!(snapshot.text(), "…fghijkl");
1238
1239            // Edit within one of the folds.
1240            buffer.update(cx, |buffer, cx| buffer.edit(vec![0..1], "12345", cx));
1241            let (snapshot, _) = map.read(cx.as_ref());
1242            assert_eq!(snapshot.text(), "12345…fghijkl");
1243        }
1244    }
1245
1246    #[gpui::test]
1247    fn test_overlapping_folds(cx: &mut gpui::MutableAppContext) {
1248        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1249        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1250        let (mut writer, _, _) = map.write(cx.as_ref());
1251        writer.fold(
1252            vec![
1253                Point::new(0, 2)..Point::new(2, 2),
1254                Point::new(0, 4)..Point::new(1, 0),
1255                Point::new(1, 2)..Point::new(3, 2),
1256                Point::new(3, 1)..Point::new(4, 1),
1257            ],
1258            cx.as_ref(),
1259        );
1260        let (snapshot, _) = map.read(cx.as_ref());
1261        assert_eq!(snapshot.text(), "aa…eeeee");
1262    }
1263
1264    #[gpui::test]
1265    fn test_merging_folds_via_edit(cx: &mut gpui::MutableAppContext) {
1266        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1267        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1268
1269        let (mut writer, _, _) = map.write(cx.as_ref());
1270        writer.fold(
1271            vec![
1272                Point::new(0, 2)..Point::new(2, 2),
1273                Point::new(3, 1)..Point::new(4, 1),
1274            ],
1275            cx.as_ref(),
1276        );
1277        let (snapshot, _) = map.read(cx.as_ref());
1278        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee");
1279
1280        buffer.update(cx, |buffer, cx| {
1281            buffer.edit(Some(Point::new(2, 2)..Point::new(3, 1)), "", cx)
1282        });
1283        let (snapshot, _) = map.read(cx.as_ref());
1284        assert_eq!(snapshot.text(), "aa…eeeee");
1285    }
1286
1287    #[gpui::test]
1288    fn test_folds_in_range(cx: &mut gpui::MutableAppContext) {
1289        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(5, 6), cx));
1290        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1291        let buffer = buffer.read(cx);
1292
1293        let (mut writer, _, _) = map.write(cx.as_ref());
1294        writer.fold(
1295            vec![
1296                Point::new(0, 2)..Point::new(2, 2),
1297                Point::new(0, 4)..Point::new(1, 0),
1298                Point::new(1, 2)..Point::new(3, 2),
1299                Point::new(3, 1)..Point::new(4, 1),
1300            ],
1301            cx.as_ref(),
1302        );
1303        let (snapshot, _) = map.read(cx.as_ref());
1304        let fold_ranges = snapshot
1305            .folds_in_range(Point::new(1, 0)..Point::new(1, 3))
1306            .map(|fold| fold.start.to_point(buffer)..fold.end.to_point(buffer))
1307            .collect::<Vec<_>>();
1308        assert_eq!(
1309            fold_ranges,
1310            vec![
1311                Point::new(0, 2)..Point::new(2, 2),
1312                Point::new(1, 2)..Point::new(3, 2)
1313            ]
1314        );
1315    }
1316
1317    #[gpui::test(iterations = 100)]
1318    fn test_random_folds(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
1319        let operations = env::var("OPERATIONS")
1320            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
1321            .unwrap_or(10);
1322
1323        let buffer = cx.add_model(|cx| {
1324            let len = rng.gen_range(0..10);
1325            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
1326            Buffer::new(0, text, cx)
1327        });
1328        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1329
1330        let (mut initial_snapshot, _) = map.read(cx.as_ref());
1331        let mut snapshot_edits = Vec::new();
1332
1333        for _ in 0..operations {
1334            log::info!("text: {:?}", buffer.read(cx).text());
1335            match rng.gen_range(0..=100) {
1336                0..=59 => {
1337                    snapshot_edits.extend(map.randomly_mutate(&mut rng, cx.as_ref()));
1338                }
1339                _ => {
1340                    let edits = buffer.update(cx, |buffer, cx| {
1341                        let start_version = buffer.version.clone();
1342                        let edit_count = rng.gen_range(1..=5);
1343                        buffer.randomly_edit(&mut rng, edit_count, cx);
1344                        buffer.edits_since(start_version).collect::<Vec<_>>()
1345                    });
1346                    log::info!("editing {:?}", edits);
1347                }
1348            }
1349
1350            let buffer = map.buffer.read(cx).snapshot();
1351            let mut expected_text: String = buffer.text().into();
1352            let mut expected_buffer_rows = Vec::new();
1353            let mut next_row = buffer.max_point().row;
1354            for fold_range in map.merged_fold_ranges(cx.as_ref()).into_iter().rev() {
1355                let fold_start = buffer.point_for_offset(fold_range.start).unwrap();
1356                let fold_end = buffer.point_for_offset(fold_range.end).unwrap();
1357                expected_buffer_rows.extend((fold_end.row + 1..=next_row).rev());
1358                next_row = fold_start.row;
1359
1360                expected_text.replace_range(fold_range.start..fold_range.end, "");
1361            }
1362            expected_buffer_rows.extend((0..=next_row).rev());
1363            expected_buffer_rows.reverse();
1364
1365            let (snapshot, edits) = map.read(cx.as_ref());
1366            assert_eq!(snapshot.text(), expected_text);
1367            snapshot_edits.push((snapshot.clone(), edits));
1368
1369            for (output_row, line) in expected_text.lines().enumerate() {
1370                let line_len = snapshot.line_len(output_row as u32);
1371                assert_eq!(line_len, line.len() as u32);
1372            }
1373
1374            let longest_row = snapshot.longest_row();
1375            let longest_char_column = expected_text
1376                .split('\n')
1377                .nth(longest_row as usize)
1378                .unwrap()
1379                .chars()
1380                .count();
1381            let mut fold_point = FoldPoint::new(0, 0);
1382            let mut fold_offset = FoldOffset(0);
1383            let mut char_column = 0;
1384            for c in expected_text.chars() {
1385                let buffer_point = fold_point.to_buffer_point(&snapshot);
1386                let buffer_offset = buffer_point.to_offset(&buffer);
1387                assert_eq!(
1388                    buffer_point.to_fold_point(&snapshot, Right),
1389                    fold_point,
1390                    "{:?} -> fold point",
1391                    buffer_point,
1392                );
1393                assert_eq!(
1394                    fold_point.to_buffer_offset(&snapshot),
1395                    buffer_offset,
1396                    "fold_point.to_buffer_offset({:?})",
1397                    fold_point,
1398                );
1399                assert_eq!(
1400                    fold_point.to_offset(&snapshot),
1401                    fold_offset,
1402                    "fold_point.to_offset({:?})",
1403                    fold_point,
1404                );
1405
1406                if c == '\n' {
1407                    *fold_point.row_mut() += 1;
1408                    *fold_point.column_mut() = 0;
1409                    char_column = 0;
1410                } else {
1411                    *fold_point.column_mut() += c.len_utf8() as u32;
1412                    char_column += 1;
1413                }
1414                fold_offset.0 += c.len_utf8();
1415                if char_column > longest_char_column {
1416                    panic!(
1417                        "invalid longest row {:?} (chars {}), found row {:?} (chars: {})",
1418                        longest_row,
1419                        longest_char_column,
1420                        fold_point.row(),
1421                        char_column
1422                    );
1423                }
1424            }
1425
1426            for _ in 0..5 {
1427                let offset = snapshot
1428                    .clip_offset(FoldOffset(rng.gen_range(0..=snapshot.len().0)), Bias::Right);
1429                assert_eq!(
1430                    snapshot.chunks_at(offset).collect::<String>(),
1431                    &expected_text[offset.0..],
1432                );
1433            }
1434
1435            for (idx, buffer_row) in expected_buffer_rows.iter().enumerate() {
1436                let fold_row = Point::new(*buffer_row, 0)
1437                    .to_fold_point(&snapshot, Right)
1438                    .row();
1439                assert_eq!(
1440                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
1441                    expected_buffer_rows[idx..],
1442                );
1443            }
1444
1445            for fold_range in map.merged_fold_ranges(cx.as_ref()) {
1446                let fold_point = fold_range
1447                    .start
1448                    .to_point(&buffer)
1449                    .to_fold_point(&snapshot, Right);
1450                assert!(snapshot.is_line_folded(fold_point.row()));
1451            }
1452
1453            for _ in 0..5 {
1454                let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1455                let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1456                let expected_folds = map
1457                    .folds
1458                    .items(&buffer)
1459                    .into_iter()
1460                    .filter(|fold| {
1461                        let start = buffer.anchor_before(start);
1462                        let end = buffer.anchor_after(end);
1463                        start.cmp(&fold.0.end, &buffer).unwrap() == Ordering::Less
1464                            && end.cmp(&fold.0.start, &buffer).unwrap() == Ordering::Greater
1465                    })
1466                    .map(|fold| fold.0)
1467                    .collect::<Vec<_>>();
1468
1469                assert_eq!(
1470                    snapshot
1471                        .folds_in_range(start..end)
1472                        .cloned()
1473                        .collect::<Vec<_>>(),
1474                    expected_folds
1475                );
1476            }
1477
1478            let text = snapshot.text();
1479            for _ in 0..5 {
1480                let start_row = rng.gen_range(0..=snapshot.max_point().row());
1481                let start_column = rng.gen_range(0..=snapshot.line_len(start_row));
1482                let end_row = rng.gen_range(0..=snapshot.max_point().row());
1483                let end_column = rng.gen_range(0..=snapshot.line_len(end_row));
1484                let mut start =
1485                    snapshot.clip_point(FoldPoint::new(start_row, start_column), Bias::Left);
1486                let mut end = snapshot.clip_point(FoldPoint::new(end_row, end_column), Bias::Right);
1487                if start > end {
1488                    mem::swap(&mut start, &mut end);
1489                }
1490
1491                let lines = start..end;
1492                let bytes = start.to_offset(&snapshot)..end.to_offset(&snapshot);
1493                assert_eq!(
1494                    snapshot.text_summary_for_range(lines),
1495                    TextSummary::from(&text[bytes.start.0..bytes.end.0])
1496                )
1497            }
1498
1499            let mut text = initial_snapshot.text();
1500            for (snapshot, edits) in snapshot_edits.drain(..) {
1501                let new_text = snapshot.text();
1502                let mut delta = 0isize;
1503                for edit in edits {
1504                    let old_bytes = ((edit.old_bytes.start.0 as isize) + delta) as usize
1505                        ..((edit.old_bytes.end.0 as isize) + delta) as usize;
1506                    let new_bytes = edit.new_bytes.start.0..edit.new_bytes.end.0;
1507                    delta += edit.delta();
1508                    text.replace_range(old_bytes, &new_text[new_bytes]);
1509                }
1510
1511                assert_eq!(text, new_text);
1512                initial_snapshot = snapshot;
1513            }
1514        }
1515    }
1516
1517    #[gpui::test]
1518    fn test_buffer_rows(cx: &mut gpui::MutableAppContext) {
1519        let text = sample_text(6, 6) + "\n";
1520        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1521
1522        let mut map = FoldMap::new(buffer.clone(), cx.as_ref()).0;
1523
1524        let (mut writer, _, _) = map.write(cx.as_ref());
1525        writer.fold(
1526            vec![
1527                Point::new(0, 2)..Point::new(2, 2),
1528                Point::new(3, 1)..Point::new(4, 1),
1529            ],
1530            cx.as_ref(),
1531        );
1532
1533        let (snapshot, _) = map.read(cx.as_ref());
1534        assert_eq!(snapshot.text(), "aa…cccc\nd…eeeee\nffffff\n");
1535        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), [0, 3, 5, 6]);
1536        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [6]);
1537    }
1538
1539    impl FoldMap {
1540        fn merged_fold_ranges(&self, cx: &AppContext) -> Vec<Range<usize>> {
1541            let buffer = self.buffer.read(cx).snapshot();
1542            let mut folds = self.folds.items(&buffer);
1543            // Ensure sorting doesn't change how folds get merged and displayed.
1544            folds.sort_by(|a, b| a.0.cmp(&b.0, &buffer).unwrap());
1545            let mut fold_ranges = folds
1546                .iter()
1547                .map(|fold| fold.0.start.to_offset(&buffer)..fold.0.end.to_offset(&buffer))
1548                .peekable();
1549
1550            let mut merged_ranges = Vec::new();
1551            while let Some(mut fold_range) = fold_ranges.next() {
1552                while let Some(next_range) = fold_ranges.peek() {
1553                    if fold_range.end >= next_range.start {
1554                        if next_range.end > fold_range.end {
1555                            fold_range.end = next_range.end;
1556                        }
1557                        fold_ranges.next();
1558                    } else {
1559                        break;
1560                    }
1561                }
1562                if fold_range.end > fold_range.start {
1563                    merged_ranges.push(fold_range);
1564                }
1565            }
1566            merged_ranges
1567        }
1568
1569        pub fn randomly_mutate(
1570            &mut self,
1571            rng: &mut impl Rng,
1572            cx: &AppContext,
1573        ) -> Vec<(Snapshot, Vec<FoldEdit>)> {
1574            let mut snapshot_edits = Vec::new();
1575            match rng.gen_range(0..=100) {
1576                0..=39 if !self.folds.is_empty() => {
1577                    let buffer = self.buffer.read(cx);
1578                    let mut to_unfold = Vec::new();
1579                    for _ in 0..rng.gen_range(1..=3) {
1580                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1581                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1582                        to_unfold.push(start..end);
1583                    }
1584                    log::info!("unfolding {:?}", to_unfold);
1585                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1586                    snapshot_edits.push((snapshot, edits));
1587                    let (snapshot, edits) = writer.fold(to_unfold, cx.as_ref());
1588                    snapshot_edits.push((snapshot, edits));
1589                }
1590                _ => {
1591                    let buffer = self.buffer.read(cx);
1592                    let mut to_fold = Vec::new();
1593                    for _ in 0..rng.gen_range(1..=2) {
1594                        let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
1595                        let start = buffer.clip_offset(rng.gen_range(0..=end), Left);
1596                        to_fold.push(start..end);
1597                    }
1598                    log::info!("folding {:?}", to_fold);
1599                    let (mut writer, snapshot, edits) = self.write(cx.as_ref());
1600                    snapshot_edits.push((snapshot, edits));
1601                    let (snapshot, edits) = writer.fold(to_fold, cx.as_ref());
1602                    snapshot_edits.push((snapshot, edits));
1603                }
1604            }
1605            snapshot_edits
1606        }
1607    }
1608}