multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::Result;
   5use clock::ReplicaId;
   6use collections::{Bound, HashMap};
   7use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
   8pub use language::Completion;
   9use language::{
  10    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Outline,
  11    OutlineItem, Selection, ToOffset as _, ToPoint as _, ToPointUtf16 as _, TransactionId,
  12};
  13use project::Project;
  14use std::{
  15    cell::{Ref, RefCell},
  16    cmp, fmt, io,
  17    iter::{self, FromIterator},
  18    ops::{Range, RangeBounds, Sub},
  19    str,
  20    sync::Arc,
  21    time::{Duration, Instant},
  22};
  23use sum_tree::{Bias, Cursor, SumTree};
  24use text::{
  25    locator::Locator,
  26    rope::TextDimension,
  27    subscription::{Subscription, Topic},
  28    AnchorRangeExt as _, Edit, Point, PointUtf16, TextSummary,
  29};
  30use theme::SyntaxTheme;
  31
  32const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  33
  34pub type ExcerptId = Locator;
  35
  36pub struct MultiBuffer {
  37    snapshot: RefCell<MultiBufferSnapshot>,
  38    buffers: RefCell<HashMap<usize, BufferState>>,
  39    subscriptions: Topic,
  40    singleton: bool,
  41    replica_id: ReplicaId,
  42    history: History,
  43    title: Option<String>,
  44}
  45
  46struct History {
  47    next_transaction_id: TransactionId,
  48    undo_stack: Vec<Transaction>,
  49    redo_stack: Vec<Transaction>,
  50    transaction_depth: usize,
  51    group_interval: Duration,
  52}
  53
  54#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Debug)]
  55pub enum CharKind {
  56    Newline,
  57    Punctuation,
  58    Whitespace,
  59    Word,
  60}
  61
  62struct Transaction {
  63    id: TransactionId,
  64    buffer_transactions: HashMap<usize, text::TransactionId>,
  65    first_edit_at: Instant,
  66    last_edit_at: Instant,
  67    suppress_grouping: bool,
  68}
  69
  70pub trait ToOffset: 'static + fmt::Debug {
  71    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
  72}
  73
  74pub trait ToPoint: 'static + fmt::Debug {
  75    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
  76}
  77
  78pub trait ToPointUtf16: 'static + fmt::Debug {
  79    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
  80}
  81
  82struct BufferState {
  83    buffer: ModelHandle<Buffer>,
  84    last_version: clock::Global,
  85    last_parse_count: usize,
  86    last_selections_update_count: usize,
  87    last_diagnostics_update_count: usize,
  88    last_file_update_count: usize,
  89    excerpts: Vec<ExcerptId>,
  90    _subscriptions: [gpui::Subscription; 2],
  91}
  92
  93#[derive(Clone, Default)]
  94pub struct MultiBufferSnapshot {
  95    singleton: bool,
  96    excerpts: SumTree<Excerpt>,
  97    parse_count: usize,
  98    diagnostics_update_count: usize,
  99    trailing_excerpt_update_count: usize,
 100    is_dirty: bool,
 101    has_conflict: bool,
 102}
 103
 104pub struct ExcerptBoundary {
 105    pub row: u32,
 106    pub buffer: BufferSnapshot,
 107    pub range: Range<text::Anchor>,
 108    pub starts_new_buffer: bool,
 109}
 110
 111#[derive(Clone)]
 112struct Excerpt {
 113    id: ExcerptId,
 114    buffer_id: usize,
 115    buffer: BufferSnapshot,
 116    range: Range<text::Anchor>,
 117    max_buffer_row: u32,
 118    text_summary: TextSummary,
 119    has_trailing_newline: bool,
 120}
 121
 122#[derive(Clone, Debug, Default)]
 123struct ExcerptSummary {
 124    excerpt_id: ExcerptId,
 125    max_buffer_row: u32,
 126    text: TextSummary,
 127}
 128
 129pub struct MultiBufferRows<'a> {
 130    buffer_row_range: Range<u32>,
 131    excerpts: Cursor<'a, Excerpt, Point>,
 132}
 133
 134pub struct MultiBufferChunks<'a> {
 135    range: Range<usize>,
 136    excerpts: Cursor<'a, Excerpt, usize>,
 137    excerpt_chunks: Option<ExcerptChunks<'a>>,
 138    language_aware: bool,
 139}
 140
 141pub struct MultiBufferBytes<'a> {
 142    range: Range<usize>,
 143    excerpts: Cursor<'a, Excerpt, usize>,
 144    excerpt_bytes: Option<ExcerptBytes<'a>>,
 145    chunk: &'a [u8],
 146}
 147
 148struct ExcerptChunks<'a> {
 149    content_chunks: BufferChunks<'a>,
 150    footer_height: usize,
 151}
 152
 153struct ExcerptBytes<'a> {
 154    content_bytes: language::rope::Bytes<'a>,
 155    footer_height: usize,
 156}
 157
 158impl MultiBuffer {
 159    pub fn new(replica_id: ReplicaId) -> Self {
 160        Self {
 161            snapshot: Default::default(),
 162            buffers: Default::default(),
 163            subscriptions: Default::default(),
 164            singleton: false,
 165            replica_id,
 166            history: History {
 167                next_transaction_id: Default::default(),
 168                undo_stack: Default::default(),
 169                redo_stack: Default::default(),
 170                transaction_depth: 0,
 171                group_interval: Duration::from_millis(300),
 172            },
 173            title: Default::default(),
 174        }
 175    }
 176
 177    pub fn with_title(mut self, title: String) -> Self {
 178        self.title = Some(title);
 179        self
 180    }
 181
 182    pub fn singleton(buffer: ModelHandle<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 183        let mut this = Self::new(buffer.read(cx).replica_id());
 184        this.singleton = true;
 185        this.push_excerpts(buffer, [text::Anchor::min()..text::Anchor::max()], cx);
 186        this.snapshot.borrow_mut().singleton = true;
 187        this
 188    }
 189
 190    #[cfg(any(test, feature = "test-support"))]
 191    pub fn build_simple(text: &str, cx: &mut gpui::MutableAppContext) -> ModelHandle<Self> {
 192        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
 193        cx.add_model(|cx| Self::singleton(buffer, cx))
 194    }
 195
 196    #[cfg(any(test, feature = "test-support"))]
 197    pub fn build_random(
 198        rng: &mut impl rand::Rng,
 199        cx: &mut gpui::MutableAppContext,
 200    ) -> ModelHandle<Self> {
 201        cx.add_model(|cx| {
 202            let mut multibuffer = MultiBuffer::new(0);
 203            let mutation_count = rng.gen_range(1..=5);
 204            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
 205            multibuffer
 206        })
 207    }
 208
 209    pub fn replica_id(&self) -> ReplicaId {
 210        self.replica_id
 211    }
 212
 213    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 214        self.sync(cx);
 215        self.snapshot.borrow().clone()
 216    }
 217
 218    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 219        self.sync(cx);
 220        self.snapshot.borrow()
 221    }
 222
 223    pub fn as_singleton(&self) -> Option<ModelHandle<Buffer>> {
 224        if self.singleton {
 225            return Some(
 226                self.buffers
 227                    .borrow()
 228                    .values()
 229                    .next()
 230                    .unwrap()
 231                    .buffer
 232                    .clone(),
 233            );
 234        } else {
 235            None
 236        }
 237    }
 238
 239    pub fn is_singleton(&self) -> bool {
 240        self.singleton
 241    }
 242
 243    pub fn subscribe(&mut self) -> Subscription {
 244        self.subscriptions.subscribe()
 245    }
 246
 247    pub fn edit<I, S, T>(&mut self, ranges: I, new_text: T, cx: &mut ModelContext<Self>)
 248    where
 249        I: IntoIterator<Item = Range<S>>,
 250        S: ToOffset,
 251        T: Into<String>,
 252    {
 253        self.edit_internal(ranges, new_text, false, cx)
 254    }
 255
 256    pub fn edit_with_autoindent<I, S, T>(
 257        &mut self,
 258        ranges: I,
 259        new_text: T,
 260        cx: &mut ModelContext<Self>,
 261    ) where
 262        I: IntoIterator<Item = Range<S>>,
 263        S: ToOffset,
 264        T: Into<String>,
 265    {
 266        self.edit_internal(ranges, new_text, true, cx)
 267    }
 268
 269    pub fn edit_internal<I, S, T>(
 270        &mut self,
 271        ranges_iter: I,
 272        new_text: T,
 273        autoindent: bool,
 274        cx: &mut ModelContext<Self>,
 275    ) where
 276        I: IntoIterator<Item = Range<S>>,
 277        S: ToOffset,
 278        T: Into<String>,
 279    {
 280        if self.buffers.borrow().is_empty() {
 281            return;
 282        }
 283
 284        if let Some(buffer) = self.as_singleton() {
 285            let snapshot = self.read(cx);
 286            let ranges = ranges_iter
 287                .into_iter()
 288                .map(|range| range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot));
 289            return buffer.update(cx, |buffer, cx| {
 290                if autoindent {
 291                    buffer.edit_with_autoindent(ranges, new_text, cx);
 292                } else {
 293                    buffer.edit(ranges, new_text, cx);
 294                }
 295            });
 296        }
 297
 298        let snapshot = self.read(cx);
 299        let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, bool)>> = Default::default();
 300        let mut cursor = snapshot.excerpts.cursor::<usize>();
 301        for range in ranges_iter {
 302            let start = range.start.to_offset(&snapshot);
 303            let end = range.end.to_offset(&snapshot);
 304            cursor.seek(&start, Bias::Right, &());
 305            if cursor.item().is_none() && start == *cursor.start() {
 306                cursor.prev(&());
 307            }
 308            let start_excerpt = cursor.item().expect("start offset out of bounds");
 309            let start_overshoot = start - cursor.start();
 310            let buffer_start =
 311                start_excerpt.range.start.to_offset(&start_excerpt.buffer) + start_overshoot;
 312
 313            cursor.seek(&end, Bias::Right, &());
 314            if cursor.item().is_none() && end == *cursor.start() {
 315                cursor.prev(&());
 316            }
 317            let end_excerpt = cursor.item().expect("end offset out of bounds");
 318            let end_overshoot = end - cursor.start();
 319            let buffer_end = end_excerpt.range.start.to_offset(&end_excerpt.buffer) + end_overshoot;
 320
 321            if start_excerpt.id == end_excerpt.id {
 322                buffer_edits
 323                    .entry(start_excerpt.buffer_id)
 324                    .or_insert(Vec::new())
 325                    .push((buffer_start..buffer_end, true));
 326            } else {
 327                let start_excerpt_range =
 328                    buffer_start..start_excerpt.range.end.to_offset(&start_excerpt.buffer);
 329                let end_excerpt_range =
 330                    end_excerpt.range.start.to_offset(&end_excerpt.buffer)..buffer_end;
 331                buffer_edits
 332                    .entry(start_excerpt.buffer_id)
 333                    .or_insert(Vec::new())
 334                    .push((start_excerpt_range, true));
 335                buffer_edits
 336                    .entry(end_excerpt.buffer_id)
 337                    .or_insert(Vec::new())
 338                    .push((end_excerpt_range, false));
 339
 340                cursor.seek(&start, Bias::Right, &());
 341                cursor.next(&());
 342                while let Some(excerpt) = cursor.item() {
 343                    if excerpt.id == end_excerpt.id {
 344                        break;
 345                    }
 346                    buffer_edits
 347                        .entry(excerpt.buffer_id)
 348                        .or_insert(Vec::new())
 349                        .push((excerpt.range.to_offset(&excerpt.buffer), false));
 350                    cursor.next(&());
 351                }
 352            }
 353        }
 354
 355        let new_text = new_text.into();
 356        for (buffer_id, mut edits) in buffer_edits {
 357            edits.sort_unstable_by_key(|(range, _)| range.start);
 358            self.buffers.borrow()[&buffer_id]
 359                .buffer
 360                .update(cx, |buffer, cx| {
 361                    let mut edits = edits.into_iter().peekable();
 362                    let mut insertions = Vec::new();
 363                    let mut deletions = Vec::new();
 364                    while let Some((mut range, mut is_insertion)) = edits.next() {
 365                        while let Some((next_range, next_is_insertion)) = edits.peek() {
 366                            if range.end >= next_range.start {
 367                                range.end = cmp::max(next_range.end, range.end);
 368                                is_insertion |= *next_is_insertion;
 369                                edits.next();
 370                            } else {
 371                                break;
 372                            }
 373                        }
 374
 375                        if is_insertion {
 376                            insertions.push(
 377                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 378                            );
 379                        } else if !range.is_empty() {
 380                            deletions.push(
 381                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 382                            );
 383                        }
 384                    }
 385
 386                    if autoindent {
 387                        buffer.edit_with_autoindent(deletions, "", cx);
 388                        buffer.edit_with_autoindent(insertions, new_text.clone(), cx);
 389                    } else {
 390                        buffer.edit(deletions, "", cx);
 391                        buffer.edit(insertions, new_text.clone(), cx);
 392                    }
 393                })
 394        }
 395    }
 396
 397    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 398        self.start_transaction_at(Instant::now(), cx)
 399    }
 400
 401    pub(crate) fn start_transaction_at(
 402        &mut self,
 403        now: Instant,
 404        cx: &mut ModelContext<Self>,
 405    ) -> Option<TransactionId> {
 406        if let Some(buffer) = self.as_singleton() {
 407            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 408        }
 409
 410        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 411            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 412        }
 413        self.history.start_transaction(now)
 414    }
 415
 416    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 417        self.end_transaction_at(Instant::now(), cx)
 418    }
 419
 420    pub(crate) fn end_transaction_at(
 421        &mut self,
 422        now: Instant,
 423        cx: &mut ModelContext<Self>,
 424    ) -> Option<TransactionId> {
 425        if let Some(buffer) = self.as_singleton() {
 426            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 427        }
 428
 429        let mut buffer_transactions = HashMap::default();
 430        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 431            if let Some(transaction_id) =
 432                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 433            {
 434                buffer_transactions.insert(buffer.id(), transaction_id);
 435            }
 436        }
 437
 438        if self.history.end_transaction(now, buffer_transactions) {
 439            let transaction_id = self.history.group().unwrap();
 440            Some(transaction_id)
 441        } else {
 442            None
 443        }
 444    }
 445
 446    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 447        self.history.finalize_last_transaction();
 448        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 449            buffer.update(cx, |buffer, _| {
 450                buffer.finalize_last_transaction();
 451            });
 452        }
 453    }
 454
 455    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T)
 456    where
 457        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
 458    {
 459        self.history
 460            .push_transaction(buffer_transactions, Instant::now());
 461        self.history.finalize_last_transaction();
 462    }
 463
 464    pub fn set_active_selections(
 465        &mut self,
 466        selections: &[Selection<Anchor>],
 467        cx: &mut ModelContext<Self>,
 468    ) {
 469        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
 470            Default::default();
 471        let snapshot = self.read(cx);
 472        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 473        for selection in selections {
 474            cursor.seek(&Some(&selection.start.excerpt_id), Bias::Left, &());
 475            while let Some(excerpt) = cursor.item() {
 476                if excerpt.id > selection.end.excerpt_id {
 477                    break;
 478                }
 479
 480                let mut start = excerpt.range.start.clone();
 481                let mut end = excerpt.range.end.clone();
 482                if excerpt.id == selection.start.excerpt_id {
 483                    start = selection.start.text_anchor.clone();
 484                }
 485                if excerpt.id == selection.end.excerpt_id {
 486                    end = selection.end.text_anchor.clone();
 487                }
 488                selections_by_buffer
 489                    .entry(excerpt.buffer_id)
 490                    .or_default()
 491                    .push(Selection {
 492                        id: selection.id,
 493                        start,
 494                        end,
 495                        reversed: selection.reversed,
 496                        goal: selection.goal,
 497                    });
 498
 499                cursor.next(&());
 500            }
 501        }
 502
 503        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 504            if !selections_by_buffer.contains_key(buffer_id) {
 505                buffer_state
 506                    .buffer
 507                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 508            }
 509        }
 510
 511        for (buffer_id, mut selections) in selections_by_buffer {
 512            self.buffers.borrow()[&buffer_id]
 513                .buffer
 514                .update(cx, |buffer, cx| {
 515                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer).unwrap());
 516                    let mut selections = selections.into_iter().peekable();
 517                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 518                        let mut selection = selections.next()?;
 519                        while let Some(next_selection) = selections.peek() {
 520                            if selection
 521                                .end
 522                                .cmp(&next_selection.start, buffer)
 523                                .unwrap()
 524                                .is_ge()
 525                            {
 526                                let next_selection = selections.next().unwrap();
 527                                if next_selection
 528                                    .end
 529                                    .cmp(&selection.end, buffer)
 530                                    .unwrap()
 531                                    .is_ge()
 532                                {
 533                                    selection.end = next_selection.end;
 534                                }
 535                            } else {
 536                                break;
 537                            }
 538                        }
 539                        Some(selection)
 540                    }));
 541                    buffer.set_active_selections(merged_selections, cx);
 542                });
 543        }
 544    }
 545
 546    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 547        for buffer in self.buffers.borrow().values() {
 548            buffer
 549                .buffer
 550                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 551        }
 552    }
 553
 554    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 555        if let Some(buffer) = self.as_singleton() {
 556            return buffer.update(cx, |buffer, cx| buffer.undo(cx));
 557        }
 558
 559        while let Some(transaction) = self.history.pop_undo() {
 560            let mut undone = false;
 561            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 562                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 563                    undone |= buffer.update(cx, |buffer, cx| {
 564                        let undo_to = *buffer_transaction_id;
 565                        if let Some(entry) = buffer.peek_undo_stack() {
 566                            *buffer_transaction_id = entry.transaction_id();
 567                        }
 568                        buffer.undo_to_transaction(undo_to, cx)
 569                    });
 570                }
 571            }
 572
 573            if undone {
 574                return Some(transaction.id);
 575            }
 576        }
 577
 578        None
 579    }
 580
 581    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 582        if let Some(buffer) = self.as_singleton() {
 583            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 584        }
 585
 586        while let Some(transaction) = self.history.pop_redo() {
 587            let mut redone = false;
 588            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 589                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 590                    redone |= buffer.update(cx, |buffer, cx| {
 591                        let redo_to = *buffer_transaction_id;
 592                        if let Some(entry) = buffer.peek_redo_stack() {
 593                            *buffer_transaction_id = entry.transaction_id();
 594                        }
 595                        buffer.redo_to_transaction(redo_to, cx)
 596                    });
 597                }
 598            }
 599
 600            if redone {
 601                return Some(transaction.id);
 602            }
 603        }
 604
 605        None
 606    }
 607
 608    pub fn push_excerpts<O>(
 609        &mut self,
 610        buffer: ModelHandle<Buffer>,
 611        ranges: impl IntoIterator<Item = Range<O>>,
 612        cx: &mut ModelContext<Self>,
 613    ) -> Vec<ExcerptId>
 614    where
 615        O: text::ToOffset,
 616    {
 617        self.insert_excerpts_after(&ExcerptId::max(), buffer, ranges, cx)
 618    }
 619
 620    pub fn push_excerpts_with_context_lines<O>(
 621        &mut self,
 622        buffer: ModelHandle<Buffer>,
 623        ranges: Vec<Range<O>>,
 624        context_line_count: u32,
 625        cx: &mut ModelContext<Self>,
 626    ) -> Vec<Range<Anchor>>
 627    where
 628        O: text::ToPoint + text::ToOffset,
 629    {
 630        let buffer_id = buffer.id();
 631        let buffer_snapshot = buffer.read(cx).snapshot();
 632        let max_point = buffer_snapshot.max_point();
 633
 634        let mut range_counts = Vec::new();
 635        let mut excerpt_ranges = Vec::new();
 636        let mut range_iter = ranges
 637            .iter()
 638            .map(|range| {
 639                range.start.to_point(&buffer_snapshot)..range.end.to_point(&buffer_snapshot)
 640            })
 641            .peekable();
 642        while let Some(range) = range_iter.next() {
 643            let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
 644            let mut excerpt_end =
 645                Point::new(range.end.row + 1 + context_line_count, 0).min(max_point);
 646            let mut ranges_in_excerpt = 1;
 647
 648            while let Some(next_range) = range_iter.peek() {
 649                if next_range.start.row <= excerpt_end.row + context_line_count {
 650                    excerpt_end =
 651                        Point::new(next_range.end.row + 1 + context_line_count, 0).min(max_point);
 652                    ranges_in_excerpt += 1;
 653                    range_iter.next();
 654                } else {
 655                    break;
 656                }
 657            }
 658
 659            excerpt_ranges.push(excerpt_start..excerpt_end);
 660            range_counts.push(ranges_in_excerpt);
 661        }
 662
 663        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
 664
 665        let mut anchor_ranges = Vec::new();
 666        let mut ranges = ranges.into_iter();
 667        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
 668            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
 669                let start = Anchor {
 670                    buffer_id: Some(buffer_id),
 671                    excerpt_id: excerpt_id.clone(),
 672                    text_anchor: buffer_snapshot.anchor_after(range.start),
 673                };
 674                let end = Anchor {
 675                    buffer_id: Some(buffer_id),
 676                    excerpt_id: excerpt_id.clone(),
 677                    text_anchor: buffer_snapshot.anchor_after(range.end),
 678                };
 679                start..end
 680            }))
 681        }
 682        anchor_ranges
 683    }
 684
 685    pub fn insert_excerpts_after<O>(
 686        &mut self,
 687        prev_excerpt_id: &ExcerptId,
 688        buffer: ModelHandle<Buffer>,
 689        ranges: impl IntoIterator<Item = Range<O>>,
 690        cx: &mut ModelContext<Self>,
 691    ) -> Vec<ExcerptId>
 692    where
 693        O: text::ToOffset,
 694    {
 695        assert_eq!(self.history.transaction_depth, 0);
 696        self.sync(cx);
 697
 698        let buffer_id = buffer.id();
 699        let buffer_snapshot = buffer.read(cx).snapshot();
 700
 701        let mut buffers = self.buffers.borrow_mut();
 702        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
 703            last_version: buffer_snapshot.version().clone(),
 704            last_parse_count: buffer_snapshot.parse_count(),
 705            last_selections_update_count: buffer_snapshot.selections_update_count(),
 706            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
 707            last_file_update_count: buffer_snapshot.file_update_count(),
 708            excerpts: Default::default(),
 709            _subscriptions: [
 710                cx.observe(&buffer, |_, _, cx| cx.notify()),
 711                cx.subscribe(&buffer, Self::on_buffer_event),
 712            ],
 713            buffer,
 714        });
 715
 716        let mut snapshot = self.snapshot.borrow_mut();
 717        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 718        let mut new_excerpts = cursor.slice(&Some(prev_excerpt_id), Bias::Right, &());
 719
 720        let mut prev_id = ExcerptId::min();
 721        let edit_start = new_excerpts.summary().text.bytes;
 722        new_excerpts.update_last(
 723            |excerpt| {
 724                excerpt.has_trailing_newline = true;
 725                prev_id = excerpt.id.clone();
 726            },
 727            &(),
 728        );
 729
 730        let mut next_id = ExcerptId::max();
 731        if let Some(next_excerpt) = cursor.item() {
 732            next_id = next_excerpt.id.clone();
 733        }
 734
 735        let mut ids = Vec::new();
 736        let mut ranges = ranges.into_iter().peekable();
 737        while let Some(range) = ranges.next() {
 738            let id = ExcerptId::between(&prev_id, &next_id);
 739            if let Err(ix) = buffer_state.excerpts.binary_search(&id) {
 740                buffer_state.excerpts.insert(ix, id.clone());
 741            }
 742            let range = buffer_snapshot.anchor_before(&range.start)
 743                ..buffer_snapshot.anchor_after(&range.end);
 744            let excerpt = Excerpt::new(
 745                id.clone(),
 746                buffer_id,
 747                buffer_snapshot.clone(),
 748                range,
 749                ranges.peek().is_some() || cursor.item().is_some(),
 750            );
 751            new_excerpts.push(excerpt, &());
 752            prev_id = id.clone();
 753            ids.push(id);
 754        }
 755
 756        let edit_end = new_excerpts.summary().text.bytes;
 757
 758        let suffix = cursor.suffix(&());
 759        let changed_trailing_excerpt = suffix.is_empty();
 760        new_excerpts.push_tree(suffix, &());
 761        drop(cursor);
 762        snapshot.excerpts = new_excerpts;
 763        if changed_trailing_excerpt {
 764            snapshot.trailing_excerpt_update_count += 1;
 765        }
 766
 767        self.subscriptions.publish_mut([Edit {
 768            old: edit_start..edit_start,
 769            new: edit_start..edit_end,
 770        }]);
 771
 772        cx.notify();
 773        ids
 774    }
 775
 776    pub fn excerpt_ids_for_buffer(&self, buffer: &ModelHandle<Buffer>) -> Vec<ExcerptId> {
 777        self.buffers
 778            .borrow()
 779            .get(&buffer.id())
 780            .map_or(Vec::new(), |state| state.excerpts.clone())
 781    }
 782
 783    pub fn excerpt_containing(
 784        &self,
 785        position: impl ToOffset,
 786        cx: &AppContext,
 787    ) -> Option<(ModelHandle<Buffer>, Range<text::Anchor>)> {
 788        let snapshot = self.read(cx);
 789        let position = position.to_offset(&snapshot);
 790
 791        let mut cursor = snapshot.excerpts.cursor::<usize>();
 792        cursor.seek(&position, Bias::Right, &());
 793        cursor.item().map(|excerpt| {
 794            (
 795                self.buffers
 796                    .borrow()
 797                    .get(&excerpt.buffer_id)
 798                    .unwrap()
 799                    .buffer
 800                    .clone(),
 801                excerpt.range.clone(),
 802            )
 803        })
 804    }
 805
 806    pub fn range_to_buffer_ranges<'a, T: ToOffset>(
 807        &'a self,
 808        range: Range<T>,
 809        cx: &AppContext,
 810    ) -> Vec<(ModelHandle<Buffer>, Range<usize>)> {
 811        let snapshot = self.read(cx);
 812        let start = range.start.to_offset(&snapshot);
 813        let end = range.end.to_offset(&snapshot);
 814
 815        let mut result = Vec::new();
 816        let mut cursor = snapshot.excerpts.cursor::<usize>();
 817        cursor.seek(&start, Bias::Right, &());
 818        while let Some(excerpt) = cursor.item() {
 819            if *cursor.start() > end {
 820                break;
 821            }
 822
 823            let mut end_before_newline = cursor.end(&());
 824            if excerpt.has_trailing_newline {
 825                end_before_newline -= 1;
 826            }
 827            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
 828            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
 829            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
 830            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
 831            result.push((buffer, start..end));
 832            cursor.next(&());
 833        }
 834
 835        result
 836    }
 837
 838    pub fn remove_excerpts<'a>(
 839        &mut self,
 840        excerpt_ids: impl IntoIterator<Item = &'a ExcerptId>,
 841        cx: &mut ModelContext<Self>,
 842    ) {
 843        let mut buffers = self.buffers.borrow_mut();
 844        let mut snapshot = self.snapshot.borrow_mut();
 845        let mut new_excerpts = SumTree::new();
 846        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 847        let mut edits = Vec::new();
 848        let mut excerpt_ids = excerpt_ids.into_iter().peekable();
 849
 850        while let Some(mut excerpt_id) = excerpt_ids.next() {
 851            // Seek to the next excerpt to remove, preserving any preceding excerpts.
 852            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
 853            if let Some(mut excerpt) = cursor.item() {
 854                if excerpt.id != *excerpt_id {
 855                    continue;
 856                }
 857                let mut old_start = cursor.start().1;
 858
 859                // Skip over the removed excerpt.
 860                loop {
 861                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
 862                        buffer_state.excerpts.retain(|id| id != excerpt_id);
 863                        if buffer_state.excerpts.is_empty() {
 864                            buffers.remove(&excerpt.buffer_id);
 865                        }
 866                    }
 867                    cursor.next(&());
 868
 869                    // Skip over any subsequent excerpts that are also removed.
 870                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
 871                        if let Some(next_excerpt) = cursor.item() {
 872                            if next_excerpt.id == *next_excerpt_id {
 873                                excerpt = next_excerpt;
 874                                excerpt_id = excerpt_ids.next().unwrap();
 875                                continue;
 876                            }
 877                        }
 878                    }
 879
 880                    break;
 881                }
 882
 883                // When removing the last excerpt, remove the trailing newline from
 884                // the previous excerpt.
 885                if cursor.item().is_none() && old_start > 0 {
 886                    old_start -= 1;
 887                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
 888                }
 889
 890                // Push an edit for the removal of this run of excerpts.
 891                let old_end = cursor.start().1;
 892                let new_start = new_excerpts.summary().text.bytes;
 893                edits.push(Edit {
 894                    old: old_start..old_end,
 895                    new: new_start..new_start,
 896                });
 897            }
 898        }
 899        let suffix = cursor.suffix(&());
 900        let changed_trailing_excerpt = suffix.is_empty();
 901        new_excerpts.push_tree(suffix, &());
 902        drop(cursor);
 903        snapshot.excerpts = new_excerpts;
 904        if changed_trailing_excerpt {
 905            snapshot.trailing_excerpt_update_count += 1;
 906        }
 907
 908        self.subscriptions.publish_mut(edits);
 909        cx.notify();
 910    }
 911
 912    pub fn text_anchor_for_position<'a, T: ToOffset>(
 913        &'a self,
 914        position: T,
 915        cx: &AppContext,
 916    ) -> Option<(ModelHandle<Buffer>, language::Anchor)> {
 917        let snapshot = self.read(cx);
 918        let anchor = snapshot.anchor_before(position);
 919        Some((
 920            self.buffers.borrow()[&anchor.buffer_id?].buffer.clone(),
 921            anchor.text_anchor,
 922        ))
 923    }
 924
 925    fn on_buffer_event(
 926        &mut self,
 927        _: ModelHandle<Buffer>,
 928        event: &Event,
 929        cx: &mut ModelContext<Self>,
 930    ) {
 931        cx.emit(event.clone());
 932    }
 933
 934    pub fn format(
 935        &mut self,
 936        project: ModelHandle<Project>,
 937        cx: &mut ModelContext<Self>,
 938    ) -> Task<Result<()>> {
 939        let buffers = self
 940            .buffers
 941            .borrow()
 942            .values()
 943            .map(|state| state.buffer.clone())
 944            .collect();
 945        let transaction = project.update(cx, |project, cx| project.format(buffers, true, cx));
 946        cx.spawn(|this, mut cx| async move {
 947            let transaction = transaction.await?;
 948            this.update(&mut cx, |this, _| {
 949                if !this.singleton {
 950                    this.push_transaction(&transaction.0);
 951                }
 952            });
 953            Ok(())
 954        })
 955    }
 956
 957    pub fn save(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 958        let mut save_tasks = Vec::new();
 959        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 960            save_tasks.push(buffer.update(cx, |buffer, cx| buffer.save(cx)));
 961        }
 962
 963        cx.spawn(|_, _| async move {
 964            for save in save_tasks {
 965                save.await?;
 966            }
 967            Ok(())
 968        })
 969    }
 970
 971    pub fn is_completion_trigger<T>(&self, position: T, text: &str, cx: &AppContext) -> bool
 972    where
 973        T: ToOffset,
 974    {
 975        let mut chars = text.chars();
 976        let char = if let Some(char) = chars.next() {
 977            char
 978        } else {
 979            return false;
 980        };
 981        if chars.next().is_some() {
 982            return false;
 983        }
 984
 985        if char.is_alphanumeric() || char == '_' {
 986            return true;
 987        }
 988
 989        let snapshot = self.snapshot(cx);
 990        let anchor = snapshot.anchor_before(position);
 991        anchor.buffer_id.map_or(false, |buffer_id| {
 992            let buffer = self.buffers.borrow()[&buffer_id].buffer.clone();
 993            buffer
 994                .read(cx)
 995                .completion_triggers()
 996                .iter()
 997                .any(|string| string == text)
 998        })
 999    }
1000
1001    pub fn language<'a>(&self, cx: &'a AppContext) -> Option<&'a Arc<Language>> {
1002        self.buffers
1003            .borrow()
1004            .values()
1005            .next()
1006            .and_then(|state| state.buffer.read(cx).language())
1007    }
1008
1009    pub fn file<'a>(&self, cx: &'a AppContext) -> Option<&'a dyn File> {
1010        self.as_singleton()?.read(cx).file()
1011    }
1012
1013    pub fn title(&self, cx: &AppContext) -> String {
1014        if let Some(title) = self.title.clone() {
1015            title
1016        } else if let Some(file) = self.file(cx) {
1017            file.file_name(cx).to_string_lossy().into()
1018        } else {
1019            "untitled".into()
1020        }
1021    }
1022
1023    #[cfg(test)]
1024    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1025        self.as_singleton().unwrap().read(cx).is_parsing()
1026    }
1027
1028    fn sync(&self, cx: &AppContext) {
1029        let mut snapshot = self.snapshot.borrow_mut();
1030        let mut excerpts_to_edit = Vec::new();
1031        let mut reparsed = false;
1032        let mut diagnostics_updated = false;
1033        let mut is_dirty = false;
1034        let mut has_conflict = false;
1035        let mut buffers = self.buffers.borrow_mut();
1036        for buffer_state in buffers.values_mut() {
1037            let buffer = buffer_state.buffer.read(cx);
1038            let version = buffer.version();
1039            let parse_count = buffer.parse_count();
1040            let selections_update_count = buffer.selections_update_count();
1041            let diagnostics_update_count = buffer.diagnostics_update_count();
1042            let file_update_count = buffer.file_update_count();
1043
1044            let buffer_edited = version.changed_since(&buffer_state.last_version);
1045            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
1046            let buffer_selections_updated =
1047                selections_update_count > buffer_state.last_selections_update_count;
1048            let buffer_diagnostics_updated =
1049                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
1050            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
1051            if buffer_edited
1052                || buffer_reparsed
1053                || buffer_selections_updated
1054                || buffer_diagnostics_updated
1055                || buffer_file_updated
1056            {
1057                buffer_state.last_version = version;
1058                buffer_state.last_parse_count = parse_count;
1059                buffer_state.last_selections_update_count = selections_update_count;
1060                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
1061                buffer_state.last_file_update_count = file_update_count;
1062                excerpts_to_edit.extend(
1063                    buffer_state
1064                        .excerpts
1065                        .iter()
1066                        .map(|excerpt_id| (excerpt_id, buffer_state.buffer.clone(), buffer_edited)),
1067                );
1068            }
1069
1070            reparsed |= buffer_reparsed;
1071            diagnostics_updated |= buffer_diagnostics_updated;
1072            is_dirty |= buffer.is_dirty();
1073            has_conflict |= buffer.has_conflict();
1074        }
1075        if reparsed {
1076            snapshot.parse_count += 1;
1077        }
1078        if diagnostics_updated {
1079            snapshot.diagnostics_update_count += 1;
1080        }
1081        snapshot.is_dirty = is_dirty;
1082        snapshot.has_conflict = has_conflict;
1083
1084        excerpts_to_edit.sort_unstable_by_key(|(excerpt_id, _, _)| *excerpt_id);
1085
1086        let mut edits = Vec::new();
1087        let mut new_excerpts = SumTree::new();
1088        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
1089
1090        for (id, buffer, buffer_edited) in excerpts_to_edit {
1091            new_excerpts.push_tree(cursor.slice(&Some(id), Bias::Left, &()), &());
1092            let old_excerpt = cursor.item().unwrap();
1093            let buffer_id = buffer.id();
1094            let buffer = buffer.read(cx);
1095
1096            let mut new_excerpt;
1097            if buffer_edited {
1098                edits.extend(
1099                    buffer
1100                        .edits_since_in_range::<usize>(
1101                            old_excerpt.buffer.version(),
1102                            old_excerpt.range.clone(),
1103                        )
1104                        .map(|mut edit| {
1105                            let excerpt_old_start = cursor.start().1;
1106                            let excerpt_new_start = new_excerpts.summary().text.bytes;
1107                            edit.old.start += excerpt_old_start;
1108                            edit.old.end += excerpt_old_start;
1109                            edit.new.start += excerpt_new_start;
1110                            edit.new.end += excerpt_new_start;
1111                            edit
1112                        }),
1113                );
1114
1115                new_excerpt = Excerpt::new(
1116                    id.clone(),
1117                    buffer_id,
1118                    buffer.snapshot(),
1119                    old_excerpt.range.clone(),
1120                    old_excerpt.has_trailing_newline,
1121                );
1122            } else {
1123                new_excerpt = old_excerpt.clone();
1124                new_excerpt.buffer = buffer.snapshot();
1125            }
1126
1127            new_excerpts.push(new_excerpt, &());
1128            cursor.next(&());
1129        }
1130        new_excerpts.push_tree(cursor.suffix(&()), &());
1131
1132        drop(cursor);
1133        snapshot.excerpts = new_excerpts;
1134
1135        self.subscriptions.publish(edits);
1136    }
1137}
1138
1139#[cfg(any(test, feature = "test-support"))]
1140impl MultiBuffer {
1141    pub fn randomly_edit(
1142        &mut self,
1143        rng: &mut impl rand::Rng,
1144        count: usize,
1145        cx: &mut ModelContext<Self>,
1146    ) {
1147        use text::RandomCharIter;
1148
1149        let snapshot = self.read(cx);
1150        let mut old_ranges: Vec<Range<usize>> = Vec::new();
1151        for _ in 0..count {
1152            let last_end = old_ranges.last().map_or(0, |last_range| last_range.end + 1);
1153            if last_end > snapshot.len() {
1154                break;
1155            }
1156            let end_ix = snapshot.clip_offset(rng.gen_range(0..=last_end), Bias::Right);
1157            let start_ix = snapshot.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1158            old_ranges.push(start_ix..end_ix);
1159        }
1160        let new_text_len = rng.gen_range(0..10);
1161        let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1162        log::info!("mutating multi-buffer at {:?}: {:?}", old_ranges, new_text);
1163        drop(snapshot);
1164
1165        self.edit(old_ranges.iter().cloned(), new_text.as_str(), cx);
1166    }
1167
1168    pub fn randomly_edit_excerpts(
1169        &mut self,
1170        rng: &mut impl rand::Rng,
1171        mutation_count: usize,
1172        cx: &mut ModelContext<Self>,
1173    ) {
1174        use rand::prelude::*;
1175        use std::env;
1176        use text::RandomCharIter;
1177
1178        let max_excerpts = env::var("MAX_EXCERPTS")
1179            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1180            .unwrap_or(5);
1181
1182        let mut buffers = Vec::new();
1183        for _ in 0..mutation_count {
1184            let excerpt_ids = self
1185                .buffers
1186                .borrow()
1187                .values()
1188                .flat_map(|b| &b.excerpts)
1189                .cloned()
1190                .collect::<Vec<_>>();
1191            if excerpt_ids.len() == 0 || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1192                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1193                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1194                    buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
1195                    let buffer = buffers.last().unwrap();
1196                    log::info!(
1197                        "Creating new buffer {} with text: {:?}",
1198                        buffer.id(),
1199                        buffer.read(cx).text()
1200                    );
1201                    buffers.last().unwrap().clone()
1202                } else {
1203                    self.buffers
1204                        .borrow()
1205                        .values()
1206                        .choose(rng)
1207                        .unwrap()
1208                        .buffer
1209                        .clone()
1210                };
1211
1212                let buffer = buffer_handle.read(cx);
1213                let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1214                let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1215                log::info!(
1216                    "Inserting excerpt from buffer {} and range {:?}: {:?}",
1217                    buffer_handle.id(),
1218                    start_ix..end_ix,
1219                    &buffer.text()[start_ix..end_ix]
1220                );
1221
1222                let excerpt_id = self.push_excerpts(buffer_handle.clone(), [start_ix..end_ix], cx);
1223                log::info!("Inserted with id: {:?}", excerpt_id);
1224            } else {
1225                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1226                let mut excerpts_to_remove = excerpt_ids
1227                    .choose_multiple(rng, remove_count)
1228                    .cloned()
1229                    .collect::<Vec<_>>();
1230                excerpts_to_remove.sort();
1231                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1232                self.remove_excerpts(&excerpts_to_remove, cx);
1233            }
1234        }
1235    }
1236
1237    pub fn randomly_mutate(
1238        &mut self,
1239        rng: &mut impl rand::Rng,
1240        mutation_count: usize,
1241        cx: &mut ModelContext<Self>,
1242    ) {
1243        if rng.gen_bool(0.7) || self.singleton {
1244            self.randomly_edit(rng, mutation_count, cx);
1245        } else {
1246            self.randomly_edit_excerpts(rng, mutation_count, cx);
1247        }
1248    }
1249}
1250
1251impl Entity for MultiBuffer {
1252    type Event = language::Event;
1253}
1254
1255impl MultiBufferSnapshot {
1256    pub fn text(&self) -> String {
1257        self.chunks(0..self.len(), false)
1258            .map(|chunk| chunk.text)
1259            .collect()
1260    }
1261
1262    pub fn reversed_chars_at<'a, T: ToOffset>(
1263        &'a self,
1264        position: T,
1265    ) -> impl Iterator<Item = char> + 'a {
1266        let mut offset = position.to_offset(self);
1267        let mut cursor = self.excerpts.cursor::<usize>();
1268        cursor.seek(&offset, Bias::Left, &());
1269        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1270            let end_before_footer = cursor.start() + excerpt.text_summary.bytes;
1271            let start = excerpt.range.start.to_offset(&excerpt.buffer);
1272            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1273            excerpt.buffer.reversed_chunks_in_range(start..end)
1274        });
1275        iter::from_fn(move || {
1276            if offset == *cursor.start() {
1277                cursor.prev(&());
1278                let excerpt = cursor.item()?;
1279                excerpt_chunks = Some(
1280                    excerpt
1281                        .buffer
1282                        .reversed_chunks_in_range(excerpt.range.clone()),
1283                );
1284            }
1285
1286            let excerpt = cursor.item().unwrap();
1287            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1288                offset -= 1;
1289                Some("\n")
1290            } else {
1291                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1292                offset -= chunk.len();
1293                Some(chunk)
1294            }
1295        })
1296        .flat_map(|c| c.chars().rev())
1297    }
1298
1299    pub fn chars_at<'a, T: ToOffset>(&'a self, position: T) -> impl Iterator<Item = char> + 'a {
1300        let offset = position.to_offset(self);
1301        self.text_for_range(offset..self.len())
1302            .flat_map(|chunk| chunk.chars())
1303    }
1304
1305    pub fn text_for_range<'a, T: ToOffset>(
1306        &'a self,
1307        range: Range<T>,
1308    ) -> impl Iterator<Item = &'a str> {
1309        self.chunks(range, false).map(|chunk| chunk.text)
1310    }
1311
1312    pub fn is_line_blank(&self, row: u32) -> bool {
1313        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1314            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1315    }
1316
1317    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1318    where
1319        T: ToOffset,
1320    {
1321        let position = position.to_offset(self);
1322        position == self.clip_offset(position, Bias::Left)
1323            && self
1324                .bytes_in_range(position..self.len())
1325                .flatten()
1326                .copied()
1327                .take(needle.len())
1328                .eq(needle.bytes())
1329    }
1330
1331    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1332        let mut start = start.to_offset(self);
1333        let mut end = start;
1334        let mut next_chars = self.chars_at(start).peekable();
1335        let mut prev_chars = self.reversed_chars_at(start).peekable();
1336        let word_kind = cmp::max(
1337            prev_chars.peek().copied().map(char_kind),
1338            next_chars.peek().copied().map(char_kind),
1339        );
1340
1341        for ch in prev_chars {
1342            if Some(char_kind(ch)) == word_kind {
1343                start -= ch.len_utf8();
1344            } else {
1345                break;
1346            }
1347        }
1348
1349        for ch in next_chars {
1350            if Some(char_kind(ch)) == word_kind {
1351                end += ch.len_utf8();
1352            } else {
1353                break;
1354            }
1355        }
1356
1357        (start..end, word_kind)
1358    }
1359
1360    fn as_singleton(&self) -> Option<&Excerpt> {
1361        if self.singleton {
1362            self.excerpts.iter().next()
1363        } else {
1364            None
1365        }
1366    }
1367
1368    pub fn len(&self) -> usize {
1369        self.excerpts.summary().text.bytes
1370    }
1371
1372    pub fn max_buffer_row(&self) -> u32 {
1373        self.excerpts.summary().max_buffer_row
1374    }
1375
1376    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1377        if let Some(excerpt) = self.as_singleton() {
1378            return excerpt.buffer.clip_offset(offset, bias);
1379        }
1380
1381        let mut cursor = self.excerpts.cursor::<usize>();
1382        cursor.seek(&offset, Bias::Right, &());
1383        let overshoot = if let Some(excerpt) = cursor.item() {
1384            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1385            let buffer_offset = excerpt
1386                .buffer
1387                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
1388            buffer_offset.saturating_sub(excerpt_start)
1389        } else {
1390            0
1391        };
1392        cursor.start() + overshoot
1393    }
1394
1395    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1396        if let Some(excerpt) = self.as_singleton() {
1397            return excerpt.buffer.clip_point(point, bias);
1398        }
1399
1400        let mut cursor = self.excerpts.cursor::<Point>();
1401        cursor.seek(&point, Bias::Right, &());
1402        let overshoot = if let Some(excerpt) = cursor.item() {
1403            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1404            let buffer_point = excerpt
1405                .buffer
1406                .clip_point(excerpt_start + (point - cursor.start()), bias);
1407            buffer_point.saturating_sub(excerpt_start)
1408        } else {
1409            Point::zero()
1410        };
1411        *cursor.start() + overshoot
1412    }
1413
1414    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1415        if let Some(excerpt) = self.as_singleton() {
1416            return excerpt.buffer.clip_point_utf16(point, bias);
1417        }
1418
1419        let mut cursor = self.excerpts.cursor::<PointUtf16>();
1420        cursor.seek(&point, Bias::Right, &());
1421        let overshoot = if let Some(excerpt) = cursor.item() {
1422            let excerpt_start = excerpt
1423                .buffer
1424                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1425            let buffer_point = excerpt
1426                .buffer
1427                .clip_point_utf16(excerpt_start + (point - cursor.start()), bias);
1428            buffer_point.saturating_sub(excerpt_start)
1429        } else {
1430            PointUtf16::zero()
1431        };
1432        *cursor.start() + overshoot
1433    }
1434
1435    pub fn bytes_in_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> MultiBufferBytes<'a> {
1436        let range = range.start.to_offset(self)..range.end.to_offset(self);
1437        let mut excerpts = self.excerpts.cursor::<usize>();
1438        excerpts.seek(&range.start, Bias::Right, &());
1439
1440        let mut chunk = &[][..];
1441        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
1442            let mut excerpt_bytes = excerpt
1443                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
1444            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
1445            Some(excerpt_bytes)
1446        } else {
1447            None
1448        };
1449
1450        MultiBufferBytes {
1451            range,
1452            excerpts,
1453            excerpt_bytes,
1454            chunk,
1455        }
1456    }
1457
1458    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> MultiBufferRows<'a> {
1459        let mut result = MultiBufferRows {
1460            buffer_row_range: 0..0,
1461            excerpts: self.excerpts.cursor(),
1462        };
1463        result.seek(start_row);
1464        result
1465    }
1466
1467    pub fn chunks<'a, T: ToOffset>(
1468        &'a self,
1469        range: Range<T>,
1470        language_aware: bool,
1471    ) -> MultiBufferChunks<'a> {
1472        let range = range.start.to_offset(self)..range.end.to_offset(self);
1473        let mut chunks = MultiBufferChunks {
1474            range: range.clone(),
1475            excerpts: self.excerpts.cursor(),
1476            excerpt_chunks: None,
1477            language_aware,
1478        };
1479        chunks.seek(range.start);
1480        chunks
1481    }
1482
1483    pub fn offset_to_point(&self, offset: usize) -> Point {
1484        if let Some(excerpt) = self.as_singleton() {
1485            return excerpt.buffer.offset_to_point(offset);
1486        }
1487
1488        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1489        cursor.seek(&offset, Bias::Right, &());
1490        if let Some(excerpt) = cursor.item() {
1491            let (start_offset, start_point) = cursor.start();
1492            let overshoot = offset - start_offset;
1493            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1494            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1495            let buffer_point = excerpt
1496                .buffer
1497                .offset_to_point(excerpt_start_offset + overshoot);
1498            *start_point + (buffer_point - excerpt_start_point)
1499        } else {
1500            self.excerpts.summary().text.lines
1501        }
1502    }
1503
1504    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
1505        if let Some(excerpt) = self.as_singleton() {
1506            return excerpt.buffer.offset_to_point_utf16(offset);
1507        }
1508
1509        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
1510        cursor.seek(&offset, Bias::Right, &());
1511        if let Some(excerpt) = cursor.item() {
1512            let (start_offset, start_point) = cursor.start();
1513            let overshoot = offset - start_offset;
1514            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1515            let excerpt_start_point = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1516            let buffer_point = excerpt
1517                .buffer
1518                .offset_to_point_utf16(excerpt_start_offset + overshoot);
1519            *start_point + (buffer_point - excerpt_start_point)
1520        } else {
1521            self.excerpts.summary().text.lines_utf16
1522        }
1523    }
1524
1525    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
1526        if let Some(excerpt) = self.as_singleton() {
1527            return excerpt.buffer.point_to_point_utf16(point);
1528        }
1529
1530        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
1531        cursor.seek(&point, Bias::Right, &());
1532        if let Some(excerpt) = cursor.item() {
1533            let (start_offset, start_point) = cursor.start();
1534            let overshoot = point - start_offset;
1535            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1536            let excerpt_start_point_utf16 = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1537            let buffer_point = excerpt
1538                .buffer
1539                .point_to_point_utf16(excerpt_start_point + overshoot);
1540            *start_point + (buffer_point - excerpt_start_point_utf16)
1541        } else {
1542            self.excerpts.summary().text.lines_utf16
1543        }
1544    }
1545
1546    pub fn point_to_offset(&self, point: Point) -> usize {
1547        if let Some(excerpt) = self.as_singleton() {
1548            return excerpt.buffer.point_to_offset(point);
1549        }
1550
1551        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
1552        cursor.seek(&point, Bias::Right, &());
1553        if let Some(excerpt) = cursor.item() {
1554            let (start_point, start_offset) = cursor.start();
1555            let overshoot = point - start_point;
1556            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1557            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1558            let buffer_offset = excerpt
1559                .buffer
1560                .point_to_offset(excerpt_start_point + overshoot);
1561            *start_offset + buffer_offset - excerpt_start_offset
1562        } else {
1563            self.excerpts.summary().text.bytes
1564        }
1565    }
1566
1567    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1568        if let Some(excerpt) = self.as_singleton() {
1569            return excerpt.buffer.point_utf16_to_offset(point);
1570        }
1571
1572        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
1573        cursor.seek(&point, Bias::Right, &());
1574        if let Some(excerpt) = cursor.item() {
1575            let (start_point, start_offset) = cursor.start();
1576            let overshoot = point - start_point;
1577            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1578            let excerpt_start_point = excerpt
1579                .buffer
1580                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1581            let buffer_offset = excerpt
1582                .buffer
1583                .point_utf16_to_offset(excerpt_start_point + overshoot);
1584            *start_offset + (buffer_offset - excerpt_start_offset)
1585        } else {
1586            self.excerpts.summary().text.bytes
1587        }
1588    }
1589
1590    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1591        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
1592            buffer
1593                .indent_column_for_line(range.start.row)
1594                .min(range.end.column)
1595                .saturating_sub(range.start.column)
1596        } else {
1597            0
1598        }
1599    }
1600
1601    pub fn line_len(&self, row: u32) -> u32 {
1602        if let Some((_, range)) = self.buffer_line_for_row(row) {
1603            range.end.column - range.start.column
1604        } else {
1605            0
1606        }
1607    }
1608
1609    fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
1610        let mut cursor = self.excerpts.cursor::<Point>();
1611        cursor.seek(&Point::new(row, 0), Bias::Right, &());
1612        if let Some(excerpt) = cursor.item() {
1613            let overshoot = row - cursor.start().row;
1614            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1615            let excerpt_end = excerpt.range.end.to_point(&excerpt.buffer);
1616            let buffer_row = excerpt_start.row + overshoot;
1617            let line_start = Point::new(buffer_row, 0);
1618            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
1619            return Some((
1620                &excerpt.buffer,
1621                line_start.max(excerpt_start)..line_end.min(excerpt_end),
1622            ));
1623        }
1624        None
1625    }
1626
1627    pub fn max_point(&self) -> Point {
1628        self.text_summary().lines
1629    }
1630
1631    pub fn text_summary(&self) -> TextSummary {
1632        self.excerpts.summary().text
1633    }
1634
1635    pub fn text_summary_for_range<'a, D, O>(&'a self, range: Range<O>) -> D
1636    where
1637        D: TextDimension,
1638        O: ToOffset,
1639    {
1640        let mut summary = D::default();
1641        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
1642        let mut cursor = self.excerpts.cursor::<usize>();
1643        cursor.seek(&range.start, Bias::Right, &());
1644        if let Some(excerpt) = cursor.item() {
1645            let mut end_before_newline = cursor.end(&());
1646            if excerpt.has_trailing_newline {
1647                end_before_newline -= 1;
1648            }
1649
1650            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1651            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
1652            let end_in_excerpt =
1653                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
1654            summary.add_assign(
1655                &excerpt
1656                    .buffer
1657                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
1658            );
1659
1660            if range.end > end_before_newline {
1661                summary.add_assign(&D::from_text_summary(&TextSummary {
1662                    bytes: 1,
1663                    lines: Point::new(1 as u32, 0),
1664                    lines_utf16: PointUtf16::new(1 as u32, 0),
1665                    first_line_chars: 0,
1666                    last_line_chars: 0,
1667                    longest_row: 0,
1668                    longest_row_chars: 0,
1669                }));
1670            }
1671
1672            cursor.next(&());
1673        }
1674
1675        if range.end > *cursor.start() {
1676            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
1677                &range.end,
1678                Bias::Right,
1679                &(),
1680            )));
1681            if let Some(excerpt) = cursor.item() {
1682                range.end = cmp::max(*cursor.start(), range.end);
1683
1684                let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1685                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
1686                summary.add_assign(
1687                    &excerpt
1688                        .buffer
1689                        .text_summary_for_range(excerpt_start..end_in_excerpt),
1690                );
1691            }
1692        }
1693
1694        summary
1695    }
1696
1697    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1698    where
1699        D: TextDimension + Ord + Sub<D, Output = D>,
1700    {
1701        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1702        cursor.seek(&Some(&anchor.excerpt_id), Bias::Left, &());
1703        if cursor.item().is_none() {
1704            cursor.next(&());
1705        }
1706
1707        let mut position = D::from_text_summary(&cursor.start().text);
1708        if let Some(excerpt) = cursor.item() {
1709            if excerpt.id == anchor.excerpt_id && Some(excerpt.buffer_id) == anchor.buffer_id {
1710                let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1711                let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1712                let buffer_position = cmp::min(
1713                    excerpt_buffer_end,
1714                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
1715                );
1716                if buffer_position > excerpt_buffer_start {
1717                    position.add_assign(&(buffer_position - excerpt_buffer_start));
1718                }
1719            }
1720        }
1721        position
1722    }
1723
1724    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
1725    where
1726        D: TextDimension + Ord + Sub<D, Output = D>,
1727        I: 'a + IntoIterator<Item = &'a Anchor>,
1728    {
1729        if let Some(excerpt) = self.as_singleton() {
1730            return excerpt
1731                .buffer
1732                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
1733                .collect();
1734        }
1735
1736        let mut anchors = anchors.into_iter().peekable();
1737        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1738        let mut summaries = Vec::new();
1739        while let Some(anchor) = anchors.peek() {
1740            let excerpt_id = &anchor.excerpt_id;
1741            let buffer_id = anchor.buffer_id;
1742            let excerpt_anchors = iter::from_fn(|| {
1743                let anchor = anchors.peek()?;
1744                if anchor.excerpt_id == *excerpt_id && anchor.buffer_id == buffer_id {
1745                    Some(&anchors.next().unwrap().text_anchor)
1746                } else {
1747                    None
1748                }
1749            });
1750
1751            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
1752            if cursor.item().is_none() {
1753                cursor.next(&());
1754            }
1755
1756            let position = D::from_text_summary(&cursor.start().text);
1757            if let Some(excerpt) = cursor.item() {
1758                if excerpt.id == *excerpt_id && Some(excerpt.buffer_id) == buffer_id {
1759                    let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1760                    let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1761                    summaries.extend(
1762                        excerpt
1763                            .buffer
1764                            .summaries_for_anchors::<D, _>(excerpt_anchors)
1765                            .map(move |summary| {
1766                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
1767                                let mut position = position.clone();
1768                                let excerpt_buffer_start = excerpt_buffer_start.clone();
1769                                if summary > excerpt_buffer_start {
1770                                    position.add_assign(&(summary - excerpt_buffer_start));
1771                                }
1772                                position
1773                            }),
1774                    );
1775                    continue;
1776                }
1777            }
1778
1779            summaries.extend(excerpt_anchors.map(|_| position.clone()));
1780        }
1781
1782        summaries
1783    }
1784
1785    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
1786    where
1787        I: 'a + IntoIterator<Item = &'a Anchor>,
1788    {
1789        let mut anchors = anchors.into_iter().enumerate().peekable();
1790        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1791        let mut result = Vec::new();
1792        while let Some((_, anchor)) = anchors.peek() {
1793            let old_excerpt_id = &anchor.excerpt_id;
1794
1795            // Find the location where this anchor's excerpt should be.
1796            cursor.seek_forward(&Some(old_excerpt_id), Bias::Left, &());
1797            if cursor.item().is_none() {
1798                cursor.next(&());
1799            }
1800
1801            let next_excerpt = cursor.item();
1802            let prev_excerpt = cursor.prev_item();
1803
1804            // Process all of the anchors for this excerpt.
1805            while let Some((_, anchor)) = anchors.peek() {
1806                if anchor.excerpt_id != *old_excerpt_id {
1807                    break;
1808                }
1809                let mut kept_position = false;
1810                let (anchor_ix, anchor) = anchors.next().unwrap();
1811                let mut anchor = anchor.clone();
1812
1813                // Leave min and max anchors unchanged.
1814                if *old_excerpt_id == ExcerptId::max() || *old_excerpt_id == ExcerptId::min() {
1815                    kept_position = true;
1816                }
1817                // If the old excerpt still exists at this location, then leave
1818                // the anchor unchanged.
1819                else if next_excerpt.map_or(false, |excerpt| {
1820                    excerpt.id == *old_excerpt_id && excerpt.contains(&anchor)
1821                }) {
1822                    kept_position = true;
1823                }
1824                // If the old excerpt no longer exists at this location, then attempt to
1825                // find an equivalent position for this anchor in an adjacent excerpt.
1826                else {
1827                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
1828                        if excerpt.contains(&anchor) {
1829                            anchor.excerpt_id = excerpt.id.clone();
1830                            kept_position = true;
1831                            break;
1832                        }
1833                    }
1834                }
1835                // If there's no adjacent excerpt that contains the anchor's position,
1836                // then report that the anchor has lost its position.
1837                if !kept_position {
1838                    anchor = if let Some(excerpt) = next_excerpt {
1839                        let mut text_anchor = excerpt
1840                            .range
1841                            .start
1842                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1843                        if text_anchor
1844                            .cmp(&excerpt.range.end, &excerpt.buffer)
1845                            .unwrap()
1846                            .is_gt()
1847                        {
1848                            text_anchor = excerpt.range.end.clone();
1849                        }
1850                        Anchor {
1851                            buffer_id: Some(excerpt.buffer_id),
1852                            excerpt_id: excerpt.id.clone(),
1853                            text_anchor,
1854                        }
1855                    } else if let Some(excerpt) = prev_excerpt {
1856                        let mut text_anchor = excerpt
1857                            .range
1858                            .end
1859                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1860                        if text_anchor
1861                            .cmp(&excerpt.range.start, &excerpt.buffer)
1862                            .unwrap()
1863                            .is_lt()
1864                        {
1865                            text_anchor = excerpt.range.start.clone();
1866                        }
1867                        Anchor {
1868                            buffer_id: Some(excerpt.buffer_id),
1869                            excerpt_id: excerpt.id.clone(),
1870                            text_anchor,
1871                        }
1872                    } else if anchor.text_anchor.bias == Bias::Left {
1873                        Anchor::min()
1874                    } else {
1875                        Anchor::max()
1876                    };
1877                }
1878
1879                result.push((anchor_ix, anchor, kept_position));
1880            }
1881        }
1882        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self).unwrap());
1883        result
1884    }
1885
1886    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1887        self.anchor_at(position, Bias::Left)
1888    }
1889
1890    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1891        self.anchor_at(position, Bias::Right)
1892    }
1893
1894    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
1895        let offset = position.to_offset(self);
1896        if let Some(excerpt) = self.as_singleton() {
1897            return Anchor {
1898                buffer_id: Some(excerpt.buffer_id),
1899                excerpt_id: excerpt.id.clone(),
1900                text_anchor: excerpt.buffer.anchor_at(offset, bias),
1901            };
1902        }
1903
1904        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
1905        cursor.seek(&offset, Bias::Right, &());
1906        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
1907            cursor.prev(&());
1908        }
1909        if let Some(excerpt) = cursor.item() {
1910            let mut overshoot = offset.saturating_sub(cursor.start().0);
1911            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
1912                overshoot -= 1;
1913                bias = Bias::Right;
1914            }
1915
1916            let buffer_start = excerpt.range.start.to_offset(&excerpt.buffer);
1917            let text_anchor =
1918                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
1919            Anchor {
1920                buffer_id: Some(excerpt.buffer_id),
1921                excerpt_id: excerpt.id.clone(),
1922                text_anchor,
1923            }
1924        } else if offset == 0 && bias == Bias::Left {
1925            Anchor::min()
1926        } else {
1927            Anchor::max()
1928        }
1929    }
1930
1931    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
1932        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1933        cursor.seek(&Some(&excerpt_id), Bias::Left, &());
1934        if let Some(excerpt) = cursor.item() {
1935            if excerpt.id == excerpt_id {
1936                let text_anchor = excerpt.clip_anchor(text_anchor);
1937                drop(cursor);
1938                return Anchor {
1939                    buffer_id: Some(excerpt.buffer_id),
1940                    excerpt_id,
1941                    text_anchor,
1942                };
1943            }
1944        }
1945        panic!("excerpt not found");
1946    }
1947
1948    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
1949        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
1950            true
1951        } else if let Some((buffer_id, buffer_snapshot)) =
1952            self.buffer_snapshot_for_excerpt(&anchor.excerpt_id)
1953        {
1954            anchor.buffer_id == Some(buffer_id) && buffer_snapshot.can_resolve(&anchor.text_anchor)
1955        } else {
1956            false
1957        }
1958    }
1959
1960    pub fn excerpt_boundaries_in_range<'a, R, T>(
1961        &'a self,
1962        range: R,
1963    ) -> impl Iterator<Item = ExcerptBoundary> + 'a
1964    where
1965        R: RangeBounds<T>,
1966        T: ToOffset,
1967    {
1968        let start_offset;
1969        let start = match range.start_bound() {
1970            Bound::Included(start) => {
1971                start_offset = start.to_offset(self);
1972                Bound::Included(start_offset)
1973            }
1974            Bound::Excluded(start) => {
1975                start_offset = start.to_offset(self);
1976                Bound::Excluded(start_offset)
1977            }
1978            Bound::Unbounded => {
1979                start_offset = 0;
1980                Bound::Unbounded
1981            }
1982        };
1983        let end = match range.end_bound() {
1984            Bound::Included(end) => Bound::Included(end.to_offset(self)),
1985            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
1986            Bound::Unbounded => Bound::Unbounded,
1987        };
1988        let bounds = (start, end);
1989
1990        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1991        cursor.seek(&start_offset, Bias::Right, &());
1992        if cursor.item().is_none() {
1993            cursor.prev(&());
1994        }
1995        if !bounds.contains(&cursor.start().0) {
1996            cursor.next(&());
1997        }
1998
1999        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
2000        std::iter::from_fn(move || {
2001            if self.singleton {
2002                None
2003            } else if bounds.contains(&cursor.start().0) {
2004                let excerpt = cursor.item()?;
2005                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
2006                let boundary = ExcerptBoundary {
2007                    row: cursor.start().1.row,
2008                    buffer: excerpt.buffer.clone(),
2009                    range: excerpt.range.clone(),
2010                    starts_new_buffer,
2011                };
2012
2013                prev_buffer_id = Some(excerpt.buffer_id);
2014                cursor.next(&());
2015                Some(boundary)
2016            } else {
2017                None
2018            }
2019        })
2020    }
2021
2022    pub fn parse_count(&self) -> usize {
2023        self.parse_count
2024    }
2025
2026    pub fn enclosing_bracket_ranges<T: ToOffset>(
2027        &self,
2028        range: Range<T>,
2029    ) -> Option<(Range<usize>, Range<usize>)> {
2030        let range = range.start.to_offset(self)..range.end.to_offset(self);
2031
2032        let mut cursor = self.excerpts.cursor::<usize>();
2033        cursor.seek(&range.start, Bias::Right, &());
2034        let start_excerpt = cursor.item();
2035
2036        cursor.seek(&range.end, Bias::Right, &());
2037        let end_excerpt = cursor.item();
2038
2039        start_excerpt
2040            .zip(end_excerpt)
2041            .and_then(|(start_excerpt, end_excerpt)| {
2042                if start_excerpt.id != end_excerpt.id {
2043                    return None;
2044                }
2045
2046                let excerpt_buffer_start =
2047                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
2048                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2049
2050                let start_in_buffer =
2051                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2052                let end_in_buffer =
2053                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2054                let (mut start_bracket_range, mut end_bracket_range) = start_excerpt
2055                    .buffer
2056                    .enclosing_bracket_ranges(start_in_buffer..end_in_buffer)?;
2057
2058                if start_bracket_range.start >= excerpt_buffer_start
2059                    && end_bracket_range.end < excerpt_buffer_end
2060                {
2061                    start_bracket_range.start =
2062                        cursor.start() + (start_bracket_range.start - excerpt_buffer_start);
2063                    start_bracket_range.end =
2064                        cursor.start() + (start_bracket_range.end - excerpt_buffer_start);
2065                    end_bracket_range.start =
2066                        cursor.start() + (end_bracket_range.start - excerpt_buffer_start);
2067                    end_bracket_range.end =
2068                        cursor.start() + (end_bracket_range.end - excerpt_buffer_start);
2069                    Some((start_bracket_range, end_bracket_range))
2070                } else {
2071                    None
2072                }
2073            })
2074    }
2075
2076    pub fn diagnostics_update_count(&self) -> usize {
2077        self.diagnostics_update_count
2078    }
2079
2080    pub fn trailing_excerpt_update_count(&self) -> usize {
2081        self.trailing_excerpt_update_count
2082    }
2083
2084    pub fn language(&self) -> Option<&Arc<Language>> {
2085        self.excerpts
2086            .iter()
2087            .next()
2088            .and_then(|excerpt| excerpt.buffer.language())
2089    }
2090
2091    pub fn is_dirty(&self) -> bool {
2092        self.is_dirty
2093    }
2094
2095    pub fn has_conflict(&self) -> bool {
2096        self.has_conflict
2097    }
2098
2099    pub fn diagnostic_group<'a, O>(
2100        &'a self,
2101        group_id: usize,
2102    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2103    where
2104        O: text::FromAnchor + 'a,
2105    {
2106        self.as_singleton()
2107            .into_iter()
2108            .flat_map(move |excerpt| excerpt.buffer.diagnostic_group(group_id))
2109    }
2110
2111    pub fn diagnostics_in_range<'a, T, O>(
2112        &'a self,
2113        range: Range<T>,
2114    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2115    where
2116        T: 'a + ToOffset,
2117        O: 'a + text::FromAnchor,
2118    {
2119        self.as_singleton().into_iter().flat_map(move |excerpt| {
2120            excerpt
2121                .buffer
2122                .diagnostics_in_range(range.start.to_offset(self)..range.end.to_offset(self))
2123        })
2124    }
2125
2126    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
2127        let range = range.start.to_offset(self)..range.end.to_offset(self);
2128
2129        let mut cursor = self.excerpts.cursor::<usize>();
2130        cursor.seek(&range.start, Bias::Right, &());
2131        let start_excerpt = cursor.item();
2132
2133        cursor.seek(&range.end, Bias::Right, &());
2134        let end_excerpt = cursor.item();
2135
2136        start_excerpt
2137            .zip(end_excerpt)
2138            .and_then(|(start_excerpt, end_excerpt)| {
2139                if start_excerpt.id != end_excerpt.id {
2140                    return None;
2141                }
2142
2143                let excerpt_buffer_start =
2144                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
2145                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2146
2147                let start_in_buffer =
2148                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2149                let end_in_buffer =
2150                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2151                let mut ancestor_buffer_range = start_excerpt
2152                    .buffer
2153                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
2154                ancestor_buffer_range.start =
2155                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
2156                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
2157
2158                let start = cursor.start() + (ancestor_buffer_range.start - excerpt_buffer_start);
2159                let end = cursor.start() + (ancestor_buffer_range.end - excerpt_buffer_start);
2160                Some(start..end)
2161            })
2162    }
2163
2164    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
2165        let excerpt = self.as_singleton()?;
2166        let outline = excerpt.buffer.outline(theme)?;
2167        Some(Outline::new(
2168            outline
2169                .items
2170                .into_iter()
2171                .map(|item| OutlineItem {
2172                    depth: item.depth,
2173                    range: self.anchor_in_excerpt(excerpt.id.clone(), item.range.start)
2174                        ..self.anchor_in_excerpt(excerpt.id.clone(), item.range.end),
2175                    text: item.text,
2176                    highlight_ranges: item.highlight_ranges,
2177                    name_ranges: item.name_ranges,
2178                })
2179                .collect(),
2180        ))
2181    }
2182
2183    fn buffer_snapshot_for_excerpt<'a>(
2184        &'a self,
2185        excerpt_id: &'a ExcerptId,
2186    ) -> Option<(usize, &'a BufferSnapshot)> {
2187        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2188        cursor.seek(&Some(excerpt_id), Bias::Left, &());
2189        if let Some(excerpt) = cursor.item() {
2190            if excerpt.id == *excerpt_id {
2191                return Some((excerpt.buffer_id, &excerpt.buffer));
2192            }
2193        }
2194        None
2195    }
2196
2197    pub fn remote_selections_in_range<'a>(
2198        &'a self,
2199        range: &'a Range<Anchor>,
2200    ) -> impl 'a + Iterator<Item = (ReplicaId, Selection<Anchor>)> {
2201        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2202        cursor.seek(&Some(&range.start.excerpt_id), Bias::Left, &());
2203        cursor
2204            .take_while(move |excerpt| excerpt.id <= range.end.excerpt_id)
2205            .flat_map(move |excerpt| {
2206                let mut query_range = excerpt.range.start.clone()..excerpt.range.end.clone();
2207                if excerpt.id == range.start.excerpt_id {
2208                    query_range.start = range.start.text_anchor.clone();
2209                }
2210                if excerpt.id == range.end.excerpt_id {
2211                    query_range.end = range.end.text_anchor.clone();
2212                }
2213
2214                excerpt
2215                    .buffer
2216                    .remote_selections_in_range(query_range)
2217                    .flat_map(move |(replica_id, selections)| {
2218                        selections.map(move |selection| {
2219                            let mut start = Anchor {
2220                                buffer_id: Some(excerpt.buffer_id),
2221                                excerpt_id: excerpt.id.clone(),
2222                                text_anchor: selection.start.clone(),
2223                            };
2224                            let mut end = Anchor {
2225                                buffer_id: Some(excerpt.buffer_id),
2226                                excerpt_id: excerpt.id.clone(),
2227                                text_anchor: selection.end.clone(),
2228                            };
2229                            if range.start.cmp(&start, self).unwrap().is_gt() {
2230                                start = range.start.clone();
2231                            }
2232                            if range.end.cmp(&end, self).unwrap().is_lt() {
2233                                end = range.end.clone();
2234                            }
2235
2236                            (
2237                                replica_id,
2238                                Selection {
2239                                    id: selection.id,
2240                                    start,
2241                                    end,
2242                                    reversed: selection.reversed,
2243                                    goal: selection.goal,
2244                                },
2245                            )
2246                        })
2247                    })
2248            })
2249    }
2250}
2251
2252impl History {
2253    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
2254        self.transaction_depth += 1;
2255        if self.transaction_depth == 1 {
2256            let id = self.next_transaction_id.tick();
2257            self.undo_stack.push(Transaction {
2258                id,
2259                buffer_transactions: Default::default(),
2260                first_edit_at: now,
2261                last_edit_at: now,
2262                suppress_grouping: false,
2263            });
2264            Some(id)
2265        } else {
2266            None
2267        }
2268    }
2269
2270    fn end_transaction(
2271        &mut self,
2272        now: Instant,
2273        buffer_transactions: HashMap<usize, TransactionId>,
2274    ) -> bool {
2275        assert_ne!(self.transaction_depth, 0);
2276        self.transaction_depth -= 1;
2277        if self.transaction_depth == 0 {
2278            if buffer_transactions.is_empty() {
2279                self.undo_stack.pop();
2280                false
2281            } else {
2282                let transaction = self.undo_stack.last_mut().unwrap();
2283                transaction.last_edit_at = now;
2284                for (buffer_id, transaction_id) in buffer_transactions {
2285                    transaction
2286                        .buffer_transactions
2287                        .entry(buffer_id)
2288                        .or_insert(transaction_id);
2289                }
2290                true
2291            }
2292        } else {
2293            false
2294        }
2295    }
2296
2297    fn push_transaction<'a, T>(&mut self, buffer_transactions: T, now: Instant)
2298    where
2299        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
2300    {
2301        assert_eq!(self.transaction_depth, 0);
2302        let transaction = Transaction {
2303            id: self.next_transaction_id.tick(),
2304            buffer_transactions: buffer_transactions
2305                .into_iter()
2306                .map(|(buffer, transaction)| (buffer.id(), transaction.id))
2307                .collect(),
2308            first_edit_at: now,
2309            last_edit_at: now,
2310            suppress_grouping: false,
2311        };
2312        if !transaction.buffer_transactions.is_empty() {
2313            self.undo_stack.push(transaction);
2314        }
2315    }
2316
2317    fn finalize_last_transaction(&mut self) {
2318        if let Some(transaction) = self.undo_stack.last_mut() {
2319            transaction.suppress_grouping = true;
2320        }
2321    }
2322
2323    fn pop_undo(&mut self) -> Option<&mut Transaction> {
2324        assert_eq!(self.transaction_depth, 0);
2325        if let Some(transaction) = self.undo_stack.pop() {
2326            self.redo_stack.push(transaction);
2327            self.redo_stack.last_mut()
2328        } else {
2329            None
2330        }
2331    }
2332
2333    fn pop_redo(&mut self) -> Option<&mut Transaction> {
2334        assert_eq!(self.transaction_depth, 0);
2335        if let Some(transaction) = self.redo_stack.pop() {
2336            self.undo_stack.push(transaction);
2337            self.undo_stack.last_mut()
2338        } else {
2339            None
2340        }
2341    }
2342
2343    fn group(&mut self) -> Option<TransactionId> {
2344        let mut new_len = self.undo_stack.len();
2345        let mut transactions = self.undo_stack.iter_mut();
2346
2347        if let Some(mut transaction) = transactions.next_back() {
2348            while let Some(prev_transaction) = transactions.next_back() {
2349                if !prev_transaction.suppress_grouping
2350                    && transaction.first_edit_at - prev_transaction.last_edit_at
2351                        <= self.group_interval
2352                {
2353                    transaction = prev_transaction;
2354                    new_len -= 1;
2355                } else {
2356                    break;
2357                }
2358            }
2359        }
2360
2361        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
2362        if let Some(last_transaction) = transactions_to_keep.last_mut() {
2363            if let Some(transaction) = transactions_to_merge.last() {
2364                last_transaction.last_edit_at = transaction.last_edit_at;
2365            }
2366            for to_merge in transactions_to_merge {
2367                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
2368                    last_transaction
2369                        .buffer_transactions
2370                        .entry(*buffer_id)
2371                        .or_insert(*transaction_id);
2372                }
2373            }
2374        }
2375
2376        self.undo_stack.truncate(new_len);
2377        self.undo_stack.last().map(|t| t.id)
2378    }
2379}
2380
2381impl Excerpt {
2382    fn new(
2383        id: ExcerptId,
2384        buffer_id: usize,
2385        buffer: BufferSnapshot,
2386        range: Range<text::Anchor>,
2387        has_trailing_newline: bool,
2388    ) -> Self {
2389        Excerpt {
2390            id,
2391            max_buffer_row: range.end.to_point(&buffer).row,
2392            text_summary: buffer.text_summary_for_range::<TextSummary, _>(range.to_offset(&buffer)),
2393            buffer_id,
2394            buffer,
2395            range,
2396            has_trailing_newline,
2397        }
2398    }
2399
2400    fn chunks_in_range<'a>(
2401        &'a self,
2402        range: Range<usize>,
2403        language_aware: bool,
2404    ) -> ExcerptChunks<'a> {
2405        let content_start = self.range.start.to_offset(&self.buffer);
2406        let chunks_start = content_start + range.start;
2407        let chunks_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2408
2409        let footer_height = if self.has_trailing_newline
2410            && range.start <= self.text_summary.bytes
2411            && range.end > self.text_summary.bytes
2412        {
2413            1
2414        } else {
2415            0
2416        };
2417
2418        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
2419
2420        ExcerptChunks {
2421            content_chunks,
2422            footer_height,
2423        }
2424    }
2425
2426    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
2427        let content_start = self.range.start.to_offset(&self.buffer);
2428        let bytes_start = content_start + range.start;
2429        let bytes_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2430        let footer_height = if self.has_trailing_newline
2431            && range.start <= self.text_summary.bytes
2432            && range.end > self.text_summary.bytes
2433        {
2434            1
2435        } else {
2436            0
2437        };
2438        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
2439
2440        ExcerptBytes {
2441            content_bytes,
2442            footer_height,
2443        }
2444    }
2445
2446    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
2447        if text_anchor
2448            .cmp(&self.range.start, &self.buffer)
2449            .unwrap()
2450            .is_lt()
2451        {
2452            self.range.start.clone()
2453        } else if text_anchor
2454            .cmp(&self.range.end, &self.buffer)
2455            .unwrap()
2456            .is_gt()
2457        {
2458            self.range.end.clone()
2459        } else {
2460            text_anchor
2461        }
2462    }
2463
2464    fn contains(&self, anchor: &Anchor) -> bool {
2465        Some(self.buffer_id) == anchor.buffer_id
2466            && self
2467                .range
2468                .start
2469                .cmp(&anchor.text_anchor, &self.buffer)
2470                .unwrap()
2471                .is_le()
2472            && self
2473                .range
2474                .end
2475                .cmp(&anchor.text_anchor, &self.buffer)
2476                .unwrap()
2477                .is_ge()
2478    }
2479}
2480
2481impl fmt::Debug for Excerpt {
2482    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2483        f.debug_struct("Excerpt")
2484            .field("id", &self.id)
2485            .field("buffer_id", &self.buffer_id)
2486            .field("range", &self.range)
2487            .field("text_summary", &self.text_summary)
2488            .field("has_trailing_newline", &self.has_trailing_newline)
2489            .finish()
2490    }
2491}
2492
2493impl sum_tree::Item for Excerpt {
2494    type Summary = ExcerptSummary;
2495
2496    fn summary(&self) -> Self::Summary {
2497        let mut text = self.text_summary.clone();
2498        if self.has_trailing_newline {
2499            text += TextSummary::from("\n");
2500        }
2501        ExcerptSummary {
2502            excerpt_id: self.id.clone(),
2503            max_buffer_row: self.max_buffer_row,
2504            text,
2505        }
2506    }
2507}
2508
2509impl sum_tree::Summary for ExcerptSummary {
2510    type Context = ();
2511
2512    fn add_summary(&mut self, summary: &Self, _: &()) {
2513        debug_assert!(summary.excerpt_id > self.excerpt_id);
2514        self.excerpt_id = summary.excerpt_id.clone();
2515        self.text.add_summary(&summary.text, &());
2516        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
2517    }
2518}
2519
2520impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
2521    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2522        *self += &summary.text;
2523    }
2524}
2525
2526impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
2527    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2528        *self += summary.text.bytes;
2529    }
2530}
2531
2532impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
2533    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2534        Ord::cmp(self, &cursor_location.text.bytes)
2535    }
2536}
2537
2538impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Option<&'a ExcerptId> {
2539    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2540        Ord::cmp(self, &Some(&cursor_location.excerpt_id))
2541    }
2542}
2543
2544impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
2545    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2546        *self += summary.text.lines;
2547    }
2548}
2549
2550impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
2551    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2552        *self += summary.text.lines_utf16
2553    }
2554}
2555
2556impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
2557    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2558        *self = Some(&summary.excerpt_id);
2559    }
2560}
2561
2562impl<'a> MultiBufferRows<'a> {
2563    pub fn seek(&mut self, row: u32) {
2564        self.buffer_row_range = 0..0;
2565
2566        self.excerpts
2567            .seek_forward(&Point::new(row, 0), Bias::Right, &());
2568        if self.excerpts.item().is_none() {
2569            self.excerpts.prev(&());
2570
2571            if self.excerpts.item().is_none() && row == 0 {
2572                self.buffer_row_range = 0..1;
2573                return;
2574            }
2575        }
2576
2577        if let Some(excerpt) = self.excerpts.item() {
2578            let overshoot = row - self.excerpts.start().row;
2579            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer).row;
2580            self.buffer_row_range.start = excerpt_start + overshoot;
2581            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
2582        }
2583    }
2584}
2585
2586impl<'a> Iterator for MultiBufferRows<'a> {
2587    type Item = Option<u32>;
2588
2589    fn next(&mut self) -> Option<Self::Item> {
2590        loop {
2591            if !self.buffer_row_range.is_empty() {
2592                let row = Some(self.buffer_row_range.start);
2593                self.buffer_row_range.start += 1;
2594                return Some(row);
2595            }
2596            self.excerpts.item()?;
2597            self.excerpts.next(&());
2598            let excerpt = self.excerpts.item()?;
2599            self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
2600            self.buffer_row_range.end =
2601                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
2602        }
2603    }
2604}
2605
2606impl<'a> MultiBufferChunks<'a> {
2607    pub fn offset(&self) -> usize {
2608        self.range.start
2609    }
2610
2611    pub fn seek(&mut self, offset: usize) {
2612        self.range.start = offset;
2613        self.excerpts.seek(&offset, Bias::Right, &());
2614        if let Some(excerpt) = self.excerpts.item() {
2615            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2616                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
2617                self.language_aware,
2618            ));
2619        } else {
2620            self.excerpt_chunks = None;
2621        }
2622    }
2623}
2624
2625impl<'a> Iterator for MultiBufferChunks<'a> {
2626    type Item = Chunk<'a>;
2627
2628    fn next(&mut self) -> Option<Self::Item> {
2629        if self.range.is_empty() {
2630            None
2631        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
2632            self.range.start += chunk.text.len();
2633            Some(chunk)
2634        } else {
2635            self.excerpts.next(&());
2636            let excerpt = self.excerpts.item()?;
2637            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2638                0..self.range.end - self.excerpts.start(),
2639                self.language_aware,
2640            ));
2641            self.next()
2642        }
2643    }
2644}
2645
2646impl<'a> MultiBufferBytes<'a> {
2647    fn consume(&mut self, len: usize) {
2648        self.range.start += len;
2649        self.chunk = &self.chunk[len..];
2650
2651        if !self.range.is_empty() && self.chunk.is_empty() {
2652            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
2653                self.chunk = chunk;
2654            } else {
2655                self.excerpts.next(&());
2656                if let Some(excerpt) = self.excerpts.item() {
2657                    let mut excerpt_bytes =
2658                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
2659                    self.chunk = excerpt_bytes.next().unwrap();
2660                    self.excerpt_bytes = Some(excerpt_bytes);
2661                }
2662            }
2663        }
2664    }
2665}
2666
2667impl<'a> Iterator for MultiBufferBytes<'a> {
2668    type Item = &'a [u8];
2669
2670    fn next(&mut self) -> Option<Self::Item> {
2671        let chunk = self.chunk;
2672        if chunk.is_empty() {
2673            None
2674        } else {
2675            self.consume(chunk.len());
2676            Some(chunk)
2677        }
2678    }
2679}
2680
2681impl<'a> io::Read for MultiBufferBytes<'a> {
2682    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
2683        let len = cmp::min(buf.len(), self.chunk.len());
2684        buf[..len].copy_from_slice(&self.chunk[..len]);
2685        if len > 0 {
2686            self.consume(len);
2687        }
2688        Ok(len)
2689    }
2690}
2691
2692impl<'a> Iterator for ExcerptBytes<'a> {
2693    type Item = &'a [u8];
2694
2695    fn next(&mut self) -> Option<Self::Item> {
2696        if let Some(chunk) = self.content_bytes.next() {
2697            if !chunk.is_empty() {
2698                return Some(chunk);
2699            }
2700        }
2701
2702        if self.footer_height > 0 {
2703            let result = &NEWLINES[..self.footer_height];
2704            self.footer_height = 0;
2705            return Some(result);
2706        }
2707
2708        None
2709    }
2710}
2711
2712impl<'a> Iterator for ExcerptChunks<'a> {
2713    type Item = Chunk<'a>;
2714
2715    fn next(&mut self) -> Option<Self::Item> {
2716        if let Some(chunk) = self.content_chunks.next() {
2717            return Some(chunk);
2718        }
2719
2720        if self.footer_height > 0 {
2721            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
2722            self.footer_height = 0;
2723            return Some(Chunk {
2724                text,
2725                ..Default::default()
2726            });
2727        }
2728
2729        None
2730    }
2731}
2732
2733impl ToOffset for Point {
2734    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2735        snapshot.point_to_offset(*self)
2736    }
2737}
2738
2739impl ToOffset for PointUtf16 {
2740    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2741        snapshot.point_utf16_to_offset(*self)
2742    }
2743}
2744
2745impl ToOffset for usize {
2746    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2747        assert!(*self <= snapshot.len(), "offset is out of range");
2748        *self
2749    }
2750}
2751
2752impl ToPoint for usize {
2753    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
2754        snapshot.offset_to_point(*self)
2755    }
2756}
2757
2758impl ToPoint for Point {
2759    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
2760        *self
2761    }
2762}
2763
2764impl ToPointUtf16 for usize {
2765    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2766        snapshot.offset_to_point_utf16(*self)
2767    }
2768}
2769
2770impl ToPointUtf16 for Point {
2771    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2772        snapshot.point_to_point_utf16(*self)
2773    }
2774}
2775
2776impl ToPointUtf16 for PointUtf16 {
2777    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
2778        *self
2779    }
2780}
2781
2782pub fn char_kind(c: char) -> CharKind {
2783    if c == '\n' {
2784        CharKind::Newline
2785    } else if c.is_whitespace() {
2786        CharKind::Whitespace
2787    } else if c.is_alphanumeric() || c == '_' {
2788        CharKind::Word
2789    } else {
2790        CharKind::Punctuation
2791    }
2792}
2793
2794#[cfg(test)]
2795mod tests {
2796    use super::*;
2797    use gpui::MutableAppContext;
2798    use language::{Buffer, Rope};
2799    use rand::prelude::*;
2800    use std::env;
2801    use text::{Point, RandomCharIter};
2802    use util::test::sample_text;
2803
2804    #[gpui::test]
2805    fn test_singleton_multibuffer(cx: &mut MutableAppContext) {
2806        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2807        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2808
2809        let snapshot = multibuffer.read(cx).snapshot(cx);
2810        assert_eq!(snapshot.text(), buffer.read(cx).text());
2811
2812        assert_eq!(
2813            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2814            (0..buffer.read(cx).row_count())
2815                .map(Some)
2816                .collect::<Vec<_>>()
2817        );
2818
2819        buffer.update(cx, |buffer, cx| buffer.edit([1..3], "XXX\n", cx));
2820        let snapshot = multibuffer.read(cx).snapshot(cx);
2821
2822        assert_eq!(snapshot.text(), buffer.read(cx).text());
2823        assert_eq!(
2824            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2825            (0..buffer.read(cx).row_count())
2826                .map(Some)
2827                .collect::<Vec<_>>()
2828        );
2829    }
2830
2831    #[gpui::test]
2832    fn test_remote_multibuffer(cx: &mut MutableAppContext) {
2833        let host_buffer = cx.add_model(|cx| Buffer::new(0, "a", cx));
2834        let guest_buffer = cx.add_model(|cx| {
2835            let message = host_buffer.read(cx).to_proto();
2836            Buffer::from_proto(1, message, None, cx).unwrap()
2837        });
2838        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
2839        let snapshot = multibuffer.read(cx).snapshot(cx);
2840        assert_eq!(snapshot.text(), "a");
2841
2842        guest_buffer.update(cx, |buffer, cx| buffer.edit([1..1], "b", cx));
2843        let snapshot = multibuffer.read(cx).snapshot(cx);
2844        assert_eq!(snapshot.text(), "ab");
2845
2846        guest_buffer.update(cx, |buffer, cx| buffer.edit([2..2], "c", cx));
2847        let snapshot = multibuffer.read(cx).snapshot(cx);
2848        assert_eq!(snapshot.text(), "abc");
2849    }
2850
2851    #[gpui::test]
2852    fn test_excerpt_buffer(cx: &mut MutableAppContext) {
2853        let buffer_1 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2854        let buffer_2 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'g'), cx));
2855        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2856
2857        let subscription = multibuffer.update(cx, |multibuffer, cx| {
2858            let subscription = multibuffer.subscribe();
2859            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(1, 2)..Point::new(2, 5)], cx);
2860            assert_eq!(
2861                subscription.consume().into_inner(),
2862                [Edit {
2863                    old: 0..0,
2864                    new: 0..10
2865                }]
2866            );
2867
2868            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(3, 3)..Point::new(4, 4)], cx);
2869            multibuffer.push_excerpts(buffer_2.clone(), [Point::new(3, 1)..Point::new(3, 3)], cx);
2870            assert_eq!(
2871                subscription.consume().into_inner(),
2872                [Edit {
2873                    old: 10..10,
2874                    new: 10..22
2875                }]
2876            );
2877
2878            subscription
2879        });
2880
2881        let snapshot = multibuffer.read(cx).snapshot(cx);
2882        assert_eq!(
2883            snapshot.text(),
2884            concat!(
2885                "bbbb\n",  // Preserve newlines
2886                "ccccc\n", //
2887                "ddd\n",   //
2888                "eeee\n",  //
2889                "jj"       //
2890            )
2891        );
2892        assert_eq!(
2893            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2894            [Some(1), Some(2), Some(3), Some(4), Some(3)]
2895        );
2896        assert_eq!(
2897            snapshot.buffer_rows(2).collect::<Vec<_>>(),
2898            [Some(3), Some(4), Some(3)]
2899        );
2900        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
2901        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
2902
2903        assert_eq!(
2904            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
2905            &[
2906                (0, "bbbb\nccccc".to_string(), true),
2907                (2, "ddd\neeee".to_string(), false),
2908                (4, "jj".to_string(), true),
2909            ]
2910        );
2911        assert_eq!(
2912            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
2913            &[(0, "bbbb\nccccc".to_string(), true)]
2914        );
2915        assert_eq!(
2916            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
2917            &[]
2918        );
2919        assert_eq!(
2920            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
2921            &[]
2922        );
2923        assert_eq!(
2924            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2925            &[(2, "ddd\neeee".to_string(), false)]
2926        );
2927        assert_eq!(
2928            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2929            &[(2, "ddd\neeee".to_string(), false)]
2930        );
2931        assert_eq!(
2932            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
2933            &[(2, "ddd\neeee".to_string(), false)]
2934        );
2935        assert_eq!(
2936            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
2937            &[(4, "jj".to_string(), true)]
2938        );
2939        assert_eq!(
2940            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
2941            &[]
2942        );
2943
2944        buffer_1.update(cx, |buffer, cx| {
2945            buffer.edit(
2946                [
2947                    Point::new(0, 0)..Point::new(0, 0),
2948                    Point::new(2, 1)..Point::new(2, 3),
2949                ],
2950                "\n",
2951                cx,
2952            );
2953        });
2954
2955        let snapshot = multibuffer.read(cx).snapshot(cx);
2956        assert_eq!(
2957            snapshot.text(),
2958            concat!(
2959                "bbbb\n", // Preserve newlines
2960                "c\n",    //
2961                "cc\n",   //
2962                "ddd\n",  //
2963                "eeee\n", //
2964                "jj"      //
2965            )
2966        );
2967
2968        assert_eq!(
2969            subscription.consume().into_inner(),
2970            [Edit {
2971                old: 6..8,
2972                new: 6..7
2973            }]
2974        );
2975
2976        let snapshot = multibuffer.read(cx).snapshot(cx);
2977        assert_eq!(
2978            snapshot.clip_point(Point::new(0, 5), Bias::Left),
2979            Point::new(0, 4)
2980        );
2981        assert_eq!(
2982            snapshot.clip_point(Point::new(0, 5), Bias::Right),
2983            Point::new(0, 4)
2984        );
2985        assert_eq!(
2986            snapshot.clip_point(Point::new(5, 1), Bias::Right),
2987            Point::new(5, 1)
2988        );
2989        assert_eq!(
2990            snapshot.clip_point(Point::new(5, 2), Bias::Right),
2991            Point::new(5, 2)
2992        );
2993        assert_eq!(
2994            snapshot.clip_point(Point::new(5, 3), Bias::Right),
2995            Point::new(5, 2)
2996        );
2997
2998        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
2999            let buffer_2_excerpt_id = multibuffer.excerpt_ids_for_buffer(&buffer_2)[0].clone();
3000            multibuffer.remove_excerpts(&[buffer_2_excerpt_id], cx);
3001            multibuffer.snapshot(cx)
3002        });
3003
3004        assert_eq!(
3005            snapshot.text(),
3006            concat!(
3007                "bbbb\n", // Preserve newlines
3008                "c\n",    //
3009                "cc\n",   //
3010                "ddd\n",  //
3011                "eeee",   //
3012            )
3013        );
3014
3015        fn boundaries_in_range(
3016            range: Range<Point>,
3017            snapshot: &MultiBufferSnapshot,
3018        ) -> Vec<(u32, String, bool)> {
3019            snapshot
3020                .excerpt_boundaries_in_range(range)
3021                .map(|boundary| {
3022                    (
3023                        boundary.row,
3024                        boundary
3025                            .buffer
3026                            .text_for_range(boundary.range)
3027                            .collect::<String>(),
3028                        boundary.starts_new_buffer,
3029                    )
3030                })
3031                .collect::<Vec<_>>()
3032        }
3033    }
3034
3035    #[gpui::test]
3036    fn test_excerpts_with_context_lines(cx: &mut MutableAppContext) {
3037        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(20, 3, 'a'), cx));
3038        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3039        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
3040            multibuffer.push_excerpts_with_context_lines(
3041                buffer.clone(),
3042                vec![
3043                    Point::new(3, 2)..Point::new(4, 2),
3044                    Point::new(7, 1)..Point::new(7, 3),
3045                    Point::new(15, 0)..Point::new(15, 0),
3046                ],
3047                2,
3048                cx,
3049            )
3050        });
3051
3052        let snapshot = multibuffer.read(cx).snapshot(cx);
3053        assert_eq!(
3054            snapshot.text(),
3055            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
3056        );
3057
3058        assert_eq!(
3059            anchor_ranges
3060                .iter()
3061                .map(|range| range.to_point(&snapshot))
3062                .collect::<Vec<_>>(),
3063            vec![
3064                Point::new(2, 2)..Point::new(3, 2),
3065                Point::new(6, 1)..Point::new(6, 3),
3066                Point::new(12, 0)..Point::new(12, 0)
3067            ]
3068        );
3069    }
3070
3071    #[gpui::test]
3072    fn test_empty_excerpt_buffer(cx: &mut MutableAppContext) {
3073        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3074
3075        let snapshot = multibuffer.read(cx).snapshot(cx);
3076        assert_eq!(snapshot.text(), "");
3077        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
3078        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
3079    }
3080
3081    #[gpui::test]
3082    fn test_singleton_multibuffer_anchors(cx: &mut MutableAppContext) {
3083        let buffer = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3084        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
3085        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3086        buffer.update(cx, |buffer, cx| {
3087            buffer.edit([0..0], "X", cx);
3088            buffer.edit([5..5], "Y", cx);
3089        });
3090        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3091
3092        assert_eq!(old_snapshot.text(), "abcd");
3093        assert_eq!(new_snapshot.text(), "XabcdY");
3094
3095        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3096        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3097        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
3098        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
3099    }
3100
3101    #[gpui::test]
3102    fn test_multibuffer_anchors(cx: &mut MutableAppContext) {
3103        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3104        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "efghi", cx));
3105        let multibuffer = cx.add_model(|cx| {
3106            let mut multibuffer = MultiBuffer::new(0);
3107            multibuffer.push_excerpts(buffer_1.clone(), [0..4], cx);
3108            multibuffer.push_excerpts(buffer_2.clone(), [0..5], cx);
3109            multibuffer
3110        });
3111        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3112
3113        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
3114        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
3115        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3116        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3117        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3118        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3119
3120        buffer_1.update(cx, |buffer, cx| {
3121            buffer.edit([0..0], "W", cx);
3122            buffer.edit([5..5], "X", cx);
3123        });
3124        buffer_2.update(cx, |buffer, cx| {
3125            buffer.edit([0..0], "Y", cx);
3126            buffer.edit([6..0], "Z", cx);
3127        });
3128        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3129
3130        assert_eq!(old_snapshot.text(), "abcd\nefghi");
3131        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
3132
3133        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3134        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3135        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
3136        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
3137        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
3138        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
3139        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
3140        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
3141        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
3142        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
3143    }
3144
3145    #[gpui::test]
3146    fn test_multibuffer_resolving_anchors_after_replacing_their_excerpts(
3147        cx: &mut MutableAppContext,
3148    ) {
3149        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3150        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "ABCDEFGHIJKLMNOP", cx));
3151        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3152
3153        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
3154        // Add an excerpt from buffer 1 that spans this new insertion.
3155        buffer_1.update(cx, |buffer, cx| buffer.edit([4..4], "123", cx));
3156        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
3157            multibuffer
3158                .push_excerpts(buffer_1.clone(), [0..7], cx)
3159                .pop()
3160                .unwrap()
3161        });
3162
3163        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
3164        assert_eq!(snapshot_1.text(), "abcd123");
3165
3166        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
3167        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
3168            multibuffer.remove_excerpts([&excerpt_id_1], cx);
3169            let mut ids = multibuffer
3170                .push_excerpts(buffer_2.clone(), [0..4, 6..10, 12..16], cx)
3171                .into_iter();
3172            (ids.next().unwrap(), ids.next().unwrap())
3173        });
3174        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
3175        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
3176
3177        // The old excerpt id has been reused.
3178        assert_eq!(excerpt_id_2, excerpt_id_1);
3179
3180        // Resolve some anchors from the previous snapshot in the new snapshot.
3181        // Although there is still an excerpt with the same id, it is for
3182        // a different buffer, so we don't attempt to resolve the old text
3183        // anchor in the new buffer.
3184        assert_eq!(
3185            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
3186            0
3187        );
3188        assert_eq!(
3189            snapshot_2.summaries_for_anchors::<usize, _>(&[
3190                snapshot_1.anchor_before(2),
3191                snapshot_1.anchor_after(3)
3192            ]),
3193            vec![0, 0]
3194        );
3195        let refresh =
3196            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
3197        assert_eq!(
3198            refresh,
3199            &[
3200                (0, snapshot_2.anchor_before(0), false),
3201                (1, snapshot_2.anchor_after(0), false),
3202            ]
3203        );
3204
3205        // Replace the middle excerpt with a smaller excerpt in buffer 2,
3206        // that intersects the old excerpt.
3207        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
3208            multibuffer.remove_excerpts([&excerpt_id_3], cx);
3209            multibuffer
3210                .insert_excerpts_after(&excerpt_id_3, buffer_2.clone(), [5..8], cx)
3211                .pop()
3212                .unwrap()
3213        });
3214
3215        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
3216        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
3217        assert_ne!(excerpt_id_5, excerpt_id_3);
3218
3219        // Resolve some anchors from the previous snapshot in the new snapshot.
3220        // The anchor in the middle excerpt snaps to the beginning of the
3221        // excerpt, since it is not
3222        let anchors = [
3223            snapshot_2.anchor_before(0),
3224            snapshot_2.anchor_after(2),
3225            snapshot_2.anchor_after(6),
3226            snapshot_2.anchor_after(14),
3227        ];
3228        assert_eq!(
3229            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
3230            &[0, 2, 9, 13]
3231        );
3232
3233        let new_anchors = snapshot_3.refresh_anchors(&anchors);
3234        assert_eq!(
3235            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
3236            &[(0, true), (1, true), (2, true), (3, true)]
3237        );
3238        assert_eq!(
3239            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
3240            &[0, 2, 7, 13]
3241        );
3242    }
3243
3244    #[gpui::test(iterations = 100)]
3245    fn test_random_multibuffer(cx: &mut MutableAppContext, mut rng: StdRng) {
3246        let operations = env::var("OPERATIONS")
3247            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
3248            .unwrap_or(10);
3249
3250        let mut buffers: Vec<ModelHandle<Buffer>> = Vec::new();
3251        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3252        let mut excerpt_ids = Vec::new();
3253        let mut expected_excerpts = Vec::<(ModelHandle<Buffer>, Range<text::Anchor>)>::new();
3254        let mut anchors = Vec::new();
3255        let mut old_versions = Vec::new();
3256
3257        for _ in 0..operations {
3258            match rng.gen_range(0..100) {
3259                0..=19 if !buffers.is_empty() => {
3260                    let buffer = buffers.choose(&mut rng).unwrap();
3261                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
3262                }
3263                20..=29 if !expected_excerpts.is_empty() => {
3264                    let mut ids_to_remove = vec![];
3265                    for _ in 0..rng.gen_range(1..=3) {
3266                        if expected_excerpts.is_empty() {
3267                            break;
3268                        }
3269
3270                        let ix = rng.gen_range(0..expected_excerpts.len());
3271                        ids_to_remove.push(excerpt_ids.remove(ix));
3272                        let (buffer, range) = expected_excerpts.remove(ix);
3273                        let buffer = buffer.read(cx);
3274                        log::info!(
3275                            "Removing excerpt {}: {:?}",
3276                            ix,
3277                            buffer
3278                                .text_for_range(range.to_offset(&buffer))
3279                                .collect::<String>(),
3280                        );
3281                    }
3282                    ids_to_remove.sort_unstable();
3283                    multibuffer.update(cx, |multibuffer, cx| {
3284                        multibuffer.remove_excerpts(&ids_to_remove, cx)
3285                    });
3286                }
3287                30..=39 if !expected_excerpts.is_empty() => {
3288                    let multibuffer = multibuffer.read(cx).read(cx);
3289                    let offset =
3290                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
3291                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
3292                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
3293                    anchors.push(multibuffer.anchor_at(offset, bias));
3294                    anchors.sort_by(|a, b| a.cmp(&b, &multibuffer).unwrap());
3295                }
3296                40..=44 if !anchors.is_empty() => {
3297                    let multibuffer = multibuffer.read(cx).read(cx);
3298
3299                    anchors = multibuffer
3300                        .refresh_anchors(&anchors)
3301                        .into_iter()
3302                        .map(|a| a.1)
3303                        .collect();
3304
3305                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
3306                    // overshoot its boundaries.
3307                    let mut cursor = multibuffer.excerpts.cursor::<Option<&ExcerptId>>();
3308                    for anchor in &anchors {
3309                        if anchor.excerpt_id == ExcerptId::min()
3310                            || anchor.excerpt_id == ExcerptId::max()
3311                        {
3312                            continue;
3313                        }
3314
3315                        cursor.seek_forward(&Some(&anchor.excerpt_id), Bias::Left, &());
3316                        let excerpt = cursor.item().unwrap();
3317                        assert_eq!(excerpt.id, anchor.excerpt_id);
3318                        assert!(excerpt.contains(anchor));
3319                    }
3320                }
3321                _ => {
3322                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
3323                        let base_text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
3324                        buffers.push(cx.add_model(|cx| Buffer::new(0, base_text, cx)));
3325                        buffers.last().unwrap()
3326                    } else {
3327                        buffers.choose(&mut rng).unwrap()
3328                    };
3329
3330                    let buffer = buffer_handle.read(cx);
3331                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3332                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3333                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
3334                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
3335                    let prev_excerpt_id = excerpt_ids
3336                        .get(prev_excerpt_ix)
3337                        .cloned()
3338                        .unwrap_or(ExcerptId::max());
3339                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
3340
3341                    log::info!(
3342                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
3343                        excerpt_ix,
3344                        expected_excerpts.len(),
3345                        buffer_handle.id(),
3346                        buffer.text(),
3347                        start_ix..end_ix,
3348                        &buffer.text()[start_ix..end_ix]
3349                    );
3350
3351                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
3352                        multibuffer
3353                            .insert_excerpts_after(
3354                                &prev_excerpt_id,
3355                                buffer_handle.clone(),
3356                                [start_ix..end_ix],
3357                                cx,
3358                            )
3359                            .pop()
3360                            .unwrap()
3361                    });
3362
3363                    excerpt_ids.insert(excerpt_ix, excerpt_id);
3364                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
3365                }
3366            }
3367
3368            if rng.gen_bool(0.3) {
3369                multibuffer.update(cx, |multibuffer, cx| {
3370                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
3371                })
3372            }
3373
3374            let snapshot = multibuffer.read(cx).snapshot(cx);
3375
3376            let mut excerpt_starts = Vec::new();
3377            let mut expected_text = String::new();
3378            let mut expected_buffer_rows = Vec::new();
3379            for (buffer, range) in &expected_excerpts {
3380                let buffer = buffer.read(cx);
3381                let buffer_range = range.to_offset(buffer);
3382
3383                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
3384                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
3385                expected_text.push('\n');
3386
3387                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
3388                    ..=buffer.offset_to_point(buffer_range.end).row;
3389                for row in buffer_row_range {
3390                    expected_buffer_rows.push(Some(row));
3391                }
3392            }
3393            // Remove final trailing newline.
3394            if !expected_excerpts.is_empty() {
3395                expected_text.pop();
3396            }
3397
3398            // Always report one buffer row
3399            if expected_buffer_rows.is_empty() {
3400                expected_buffer_rows.push(Some(0));
3401            }
3402
3403            assert_eq!(snapshot.text(), expected_text);
3404            log::info!("MultiBuffer text: {:?}", expected_text);
3405
3406            assert_eq!(
3407                snapshot.buffer_rows(0).collect::<Vec<_>>(),
3408                expected_buffer_rows,
3409            );
3410
3411            for _ in 0..5 {
3412                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
3413                assert_eq!(
3414                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
3415                    &expected_buffer_rows[start_row..],
3416                    "buffer_rows({})",
3417                    start_row
3418                );
3419            }
3420
3421            assert_eq!(
3422                snapshot.max_buffer_row(),
3423                expected_buffer_rows
3424                    .into_iter()
3425                    .filter_map(|r| r)
3426                    .max()
3427                    .unwrap()
3428            );
3429
3430            let mut excerpt_starts = excerpt_starts.into_iter();
3431            for (buffer, range) in &expected_excerpts {
3432                let buffer_id = buffer.id();
3433                let buffer = buffer.read(cx);
3434                let buffer_range = range.to_offset(buffer);
3435                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
3436                let buffer_start_point_utf16 =
3437                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
3438
3439                let excerpt_start = excerpt_starts.next().unwrap();
3440                let mut offset = excerpt_start.bytes;
3441                let mut buffer_offset = buffer_range.start;
3442                let mut point = excerpt_start.lines;
3443                let mut buffer_point = buffer_start_point;
3444                let mut point_utf16 = excerpt_start.lines_utf16;
3445                let mut buffer_point_utf16 = buffer_start_point_utf16;
3446                for ch in buffer
3447                    .snapshot()
3448                    .chunks(buffer_range.clone(), false)
3449                    .flat_map(|c| c.text.chars())
3450                {
3451                    for _ in 0..ch.len_utf8() {
3452                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
3453                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
3454                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
3455                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
3456                        assert_eq!(
3457                            left_offset,
3458                            excerpt_start.bytes + (buffer_left_offset - buffer_range.start),
3459                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
3460                            offset,
3461                            buffer_id,
3462                            buffer_offset,
3463                        );
3464                        assert_eq!(
3465                            right_offset,
3466                            excerpt_start.bytes + (buffer_right_offset - buffer_range.start),
3467                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
3468                            offset,
3469                            buffer_id,
3470                            buffer_offset,
3471                        );
3472
3473                        let left_point = snapshot.clip_point(point, Bias::Left);
3474                        let right_point = snapshot.clip_point(point, Bias::Right);
3475                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
3476                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
3477                        assert_eq!(
3478                            left_point,
3479                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
3480                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
3481                            point,
3482                            buffer_id,
3483                            buffer_point,
3484                        );
3485                        assert_eq!(
3486                            right_point,
3487                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
3488                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
3489                            point,
3490                            buffer_id,
3491                            buffer_point,
3492                        );
3493
3494                        assert_eq!(
3495                            snapshot.point_to_offset(left_point),
3496                            left_offset,
3497                            "point_to_offset({:?})",
3498                            left_point,
3499                        );
3500                        assert_eq!(
3501                            snapshot.offset_to_point(left_offset),
3502                            left_point,
3503                            "offset_to_point({:?})",
3504                            left_offset,
3505                        );
3506
3507                        offset += 1;
3508                        buffer_offset += 1;
3509                        if ch == '\n' {
3510                            point += Point::new(1, 0);
3511                            buffer_point += Point::new(1, 0);
3512                        } else {
3513                            point += Point::new(0, 1);
3514                            buffer_point += Point::new(0, 1);
3515                        }
3516                    }
3517
3518                    for _ in 0..ch.len_utf16() {
3519                        let left_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Left);
3520                        let right_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Right);
3521                        let buffer_left_point_utf16 =
3522                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Left);
3523                        let buffer_right_point_utf16 =
3524                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Right);
3525                        assert_eq!(
3526                            left_point_utf16,
3527                            excerpt_start.lines_utf16
3528                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
3529                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
3530                            point_utf16,
3531                            buffer_id,
3532                            buffer_point_utf16,
3533                        );
3534                        assert_eq!(
3535                            right_point_utf16,
3536                            excerpt_start.lines_utf16
3537                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
3538                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
3539                            point_utf16,
3540                            buffer_id,
3541                            buffer_point_utf16,
3542                        );
3543
3544                        if ch == '\n' {
3545                            point_utf16 += PointUtf16::new(1, 0);
3546                            buffer_point_utf16 += PointUtf16::new(1, 0);
3547                        } else {
3548                            point_utf16 += PointUtf16::new(0, 1);
3549                            buffer_point_utf16 += PointUtf16::new(0, 1);
3550                        }
3551                    }
3552                }
3553            }
3554
3555            for (row, line) in expected_text.split('\n').enumerate() {
3556                assert_eq!(
3557                    snapshot.line_len(row as u32),
3558                    line.len() as u32,
3559                    "line_len({}).",
3560                    row
3561                );
3562            }
3563
3564            let text_rope = Rope::from(expected_text.as_str());
3565            for _ in 0..10 {
3566                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3567                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3568
3569                let text_for_range = snapshot
3570                    .text_for_range(start_ix..end_ix)
3571                    .collect::<String>();
3572                assert_eq!(
3573                    text_for_range,
3574                    &expected_text[start_ix..end_ix],
3575                    "incorrect text for range {:?}",
3576                    start_ix..end_ix
3577                );
3578
3579                let excerpted_buffer_ranges = multibuffer
3580                    .read(cx)
3581                    .range_to_buffer_ranges(start_ix..end_ix, cx);
3582                let excerpted_buffers_text = excerpted_buffer_ranges
3583                    .into_iter()
3584                    .map(|(buffer, buffer_range)| {
3585                        buffer
3586                            .read(cx)
3587                            .text_for_range(buffer_range)
3588                            .collect::<String>()
3589                    })
3590                    .collect::<Vec<_>>()
3591                    .join("\n");
3592                assert_eq!(excerpted_buffers_text, text_for_range);
3593
3594                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
3595                assert_eq!(
3596                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
3597                    expected_summary,
3598                    "incorrect summary for range {:?}",
3599                    start_ix..end_ix
3600                );
3601            }
3602
3603            // Anchor resolution
3604            for (anchor, resolved_offset) in anchors
3605                .iter()
3606                .zip(snapshot.summaries_for_anchors::<usize, _>(&anchors))
3607            {
3608                assert!(resolved_offset <= snapshot.len());
3609                assert_eq!(
3610                    snapshot.summary_for_anchor::<usize>(anchor),
3611                    resolved_offset
3612                );
3613            }
3614
3615            for _ in 0..10 {
3616                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3617                assert_eq!(
3618                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
3619                    expected_text[..end_ix].chars().rev().collect::<String>(),
3620                );
3621            }
3622
3623            for _ in 0..10 {
3624                let end_ix = rng.gen_range(0..=text_rope.len());
3625                let start_ix = rng.gen_range(0..=end_ix);
3626                assert_eq!(
3627                    snapshot
3628                        .bytes_in_range(start_ix..end_ix)
3629                        .flatten()
3630                        .copied()
3631                        .collect::<Vec<_>>(),
3632                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
3633                    "bytes_in_range({:?})",
3634                    start_ix..end_ix,
3635                );
3636            }
3637        }
3638
3639        let snapshot = multibuffer.read(cx).snapshot(cx);
3640        for (old_snapshot, subscription) in old_versions {
3641            let edits = subscription.consume().into_inner();
3642
3643            log::info!(
3644                "applying subscription edits to old text: {:?}: {:?}",
3645                old_snapshot.text(),
3646                edits,
3647            );
3648
3649            let mut text = old_snapshot.text();
3650            for edit in edits {
3651                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
3652                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
3653            }
3654            assert_eq!(text.to_string(), snapshot.text());
3655        }
3656    }
3657
3658    #[gpui::test]
3659    fn test_history(cx: &mut MutableAppContext) {
3660        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "1234", cx));
3661        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "5678", cx));
3662        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3663        let group_interval = multibuffer.read(cx).history.group_interval;
3664        multibuffer.update(cx, |multibuffer, cx| {
3665            multibuffer.push_excerpts(buffer_1.clone(), [0..buffer_1.read(cx).len()], cx);
3666            multibuffer.push_excerpts(buffer_2.clone(), [0..buffer_2.read(cx).len()], cx);
3667        });
3668
3669        let mut now = Instant::now();
3670
3671        multibuffer.update(cx, |multibuffer, cx| {
3672            multibuffer.start_transaction_at(now, cx);
3673            multibuffer.edit(
3674                [
3675                    Point::new(0, 0)..Point::new(0, 0),
3676                    Point::new(1, 0)..Point::new(1, 0),
3677                ],
3678                "A",
3679                cx,
3680            );
3681            multibuffer.edit(
3682                [
3683                    Point::new(0, 1)..Point::new(0, 1),
3684                    Point::new(1, 1)..Point::new(1, 1),
3685                ],
3686                "B",
3687                cx,
3688            );
3689            multibuffer.end_transaction_at(now, cx);
3690            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3691
3692            now += 2 * group_interval;
3693            multibuffer.start_transaction_at(now, cx);
3694            multibuffer.edit([2..2], "C", cx);
3695            multibuffer.end_transaction_at(now, cx);
3696            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3697
3698            multibuffer.undo(cx);
3699            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3700
3701            multibuffer.undo(cx);
3702            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3703
3704            multibuffer.redo(cx);
3705            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3706
3707            multibuffer.redo(cx);
3708            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3709
3710            buffer_1.update(cx, |buffer_1, cx| buffer_1.undo(cx));
3711            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3712
3713            multibuffer.undo(cx);
3714            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3715
3716            multibuffer.redo(cx);
3717            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3718
3719            multibuffer.redo(cx);
3720            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3721
3722            multibuffer.undo(cx);
3723            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3724
3725            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
3726            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3727
3728            multibuffer.undo(cx);
3729            assert_eq!(multibuffer.read(cx).text(), "C1234\n5678");
3730        });
3731    }
3732}