multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::{anyhow, Result};
   5use clock::ReplicaId;
   6use collections::{BTreeMap, Bound, HashMap, HashSet};
   7use futures::{channel::mpsc, SinkExt};
   8use git::diff::DiffHunk;
   9use gpui::{AppContext, EventEmitter, Model, ModelContext};
  10pub use language::Completion;
  11use language::{
  12    char_kind,
  13    language_settings::{language_settings, LanguageSettings},
  14    AutoindentMode, Buffer, BufferChunks, BufferSnapshot, Capability, CharKind, Chunk, CursorShape,
  15    DiagnosticEntry, File, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16,
  16    Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension, ToOffset as _,
  17    ToOffsetUtf16 as _, ToPoint as _, ToPointUtf16 as _, TransactionId, Unclipped,
  18};
  19use std::{
  20    borrow::Cow,
  21    cell::{Ref, RefCell},
  22    cmp, fmt,
  23    future::Future,
  24    io,
  25    iter::{self, FromIterator},
  26    mem,
  27    ops::{Range, RangeBounds, Sub},
  28    str,
  29    sync::Arc,
  30    time::{Duration, Instant},
  31};
  32use sum_tree::{Bias, Cursor, SumTree};
  33use text::{
  34    locator::Locator,
  35    subscription::{Subscription, Topic},
  36    BufferId, Edit, TextSummary,
  37};
  38use theme::SyntaxTheme;
  39
  40use util::post_inc;
  41
  42#[cfg(any(test, feature = "test-support"))]
  43use gpui::Context;
  44
  45const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  46
  47#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  48pub struct ExcerptId(usize);
  49
  50pub struct MultiBuffer {
  51    snapshot: RefCell<MultiBufferSnapshot>,
  52    buffers: RefCell<HashMap<BufferId, BufferState>>,
  53    next_excerpt_id: usize,
  54    subscriptions: Topic,
  55    singleton: bool,
  56    replica_id: ReplicaId,
  57    history: History,
  58    title: Option<String>,
  59    capability: Capability,
  60}
  61
  62#[derive(Clone, Debug, PartialEq, Eq)]
  63pub enum Event {
  64    ExcerptsAdded {
  65        buffer: Model<Buffer>,
  66        predecessor: ExcerptId,
  67        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  68    },
  69    ExcerptsRemoved {
  70        ids: Vec<ExcerptId>,
  71    },
  72    ExcerptsEdited {
  73        ids: Vec<ExcerptId>,
  74    },
  75    Edited {
  76        singleton_buffer_edited: bool,
  77    },
  78    TransactionUndone {
  79        transaction_id: TransactionId,
  80    },
  81    Reloaded,
  82    DiffBaseChanged,
  83    LanguageChanged,
  84    CapabilityChanged,
  85    Reparsed,
  86    Saved,
  87    FileHandleChanged,
  88    Closed,
  89    DirtyChanged,
  90    DiagnosticsUpdated,
  91}
  92
  93#[derive(Clone)]
  94struct History {
  95    next_transaction_id: TransactionId,
  96    undo_stack: Vec<Transaction>,
  97    redo_stack: Vec<Transaction>,
  98    transaction_depth: usize,
  99    group_interval: Duration,
 100}
 101
 102#[derive(Clone)]
 103struct Transaction {
 104    id: TransactionId,
 105    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 106    first_edit_at: Instant,
 107    last_edit_at: Instant,
 108    suppress_grouping: bool,
 109}
 110
 111pub trait ToOffset: 'static + fmt::Debug {
 112    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 113}
 114
 115pub trait ToOffsetUtf16: 'static + fmt::Debug {
 116    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 117}
 118
 119pub trait ToPoint: 'static + fmt::Debug {
 120    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 121}
 122
 123pub trait ToPointUtf16: 'static + fmt::Debug {
 124    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 125}
 126
 127struct BufferState {
 128    buffer: Model<Buffer>,
 129    last_version: clock::Global,
 130    last_parse_count: usize,
 131    last_selections_update_count: usize,
 132    last_diagnostics_update_count: usize,
 133    last_file_update_count: usize,
 134    last_git_diff_update_count: usize,
 135    excerpts: Vec<Locator>,
 136    _subscriptions: [gpui::Subscription; 2],
 137}
 138
 139#[derive(Clone, Default)]
 140pub struct MultiBufferSnapshot {
 141    singleton: bool,
 142    excerpts: SumTree<Excerpt>,
 143    excerpt_ids: SumTree<ExcerptIdMapping>,
 144    parse_count: usize,
 145    diagnostics_update_count: usize,
 146    trailing_excerpt_update_count: usize,
 147    git_diff_update_count: usize,
 148    edit_count: usize,
 149    is_dirty: bool,
 150    has_conflict: bool,
 151}
 152
 153pub struct ExcerptBoundary {
 154    pub id: ExcerptId,
 155    pub row: u32,
 156    pub buffer: BufferSnapshot,
 157    pub range: ExcerptRange<text::Anchor>,
 158    pub starts_new_buffer: bool,
 159}
 160
 161#[derive(Clone)]
 162struct Excerpt {
 163    id: ExcerptId,
 164    locator: Locator,
 165    buffer_id: BufferId,
 166    buffer: BufferSnapshot,
 167    range: ExcerptRange<text::Anchor>,
 168    max_buffer_row: u32,
 169    text_summary: TextSummary,
 170    has_trailing_newline: bool,
 171}
 172
 173#[derive(Clone, Debug)]
 174struct ExcerptIdMapping {
 175    id: ExcerptId,
 176    locator: Locator,
 177}
 178
 179#[derive(Clone, Debug, Eq, PartialEq)]
 180pub struct ExcerptRange<T> {
 181    pub context: Range<T>,
 182    pub primary: Option<Range<T>>,
 183}
 184
 185#[derive(Clone, Debug, Default)]
 186struct ExcerptSummary {
 187    excerpt_id: ExcerptId,
 188    excerpt_locator: Locator,
 189    max_buffer_row: u32,
 190    text: TextSummary,
 191}
 192
 193#[derive(Clone)]
 194pub struct MultiBufferRows<'a> {
 195    buffer_row_range: Range<u32>,
 196    excerpts: Cursor<'a, Excerpt, Point>,
 197}
 198
 199pub struct MultiBufferChunks<'a> {
 200    range: Range<usize>,
 201    excerpts: Cursor<'a, Excerpt, usize>,
 202    excerpt_chunks: Option<ExcerptChunks<'a>>,
 203    language_aware: bool,
 204}
 205
 206pub struct MultiBufferBytes<'a> {
 207    range: Range<usize>,
 208    excerpts: Cursor<'a, Excerpt, usize>,
 209    excerpt_bytes: Option<ExcerptBytes<'a>>,
 210    chunk: &'a [u8],
 211}
 212
 213pub struct ReversedMultiBufferBytes<'a> {
 214    range: Range<usize>,
 215    excerpts: Cursor<'a, Excerpt, usize>,
 216    excerpt_bytes: Option<ExcerptBytes<'a>>,
 217    chunk: &'a [u8],
 218}
 219
 220struct ExcerptChunks<'a> {
 221    content_chunks: BufferChunks<'a>,
 222    footer_height: usize,
 223}
 224
 225struct ExcerptBytes<'a> {
 226    content_bytes: text::Bytes<'a>,
 227    footer_height: usize,
 228}
 229
 230impl MultiBuffer {
 231    pub fn new(replica_id: ReplicaId, capability: Capability) -> Self {
 232        Self {
 233            snapshot: Default::default(),
 234            buffers: Default::default(),
 235            next_excerpt_id: 1,
 236            subscriptions: Default::default(),
 237            singleton: false,
 238            capability,
 239            replica_id,
 240            history: History {
 241                next_transaction_id: Default::default(),
 242                undo_stack: Default::default(),
 243                redo_stack: Default::default(),
 244                transaction_depth: 0,
 245                group_interval: Duration::from_millis(300),
 246            },
 247            title: Default::default(),
 248        }
 249    }
 250
 251    pub fn clone(&self, new_cx: &mut ModelContext<Self>) -> Self {
 252        let mut buffers = HashMap::default();
 253        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 254            buffers.insert(
 255                *buffer_id,
 256                BufferState {
 257                    buffer: buffer_state.buffer.clone(),
 258                    last_version: buffer_state.last_version.clone(),
 259                    last_parse_count: buffer_state.last_parse_count,
 260                    last_selections_update_count: buffer_state.last_selections_update_count,
 261                    last_diagnostics_update_count: buffer_state.last_diagnostics_update_count,
 262                    last_file_update_count: buffer_state.last_file_update_count,
 263                    last_git_diff_update_count: buffer_state.last_git_diff_update_count,
 264                    excerpts: buffer_state.excerpts.clone(),
 265                    _subscriptions: [
 266                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 267                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 268                    ],
 269                },
 270            );
 271        }
 272        Self {
 273            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 274            buffers: RefCell::new(buffers),
 275            next_excerpt_id: 1,
 276            subscriptions: Default::default(),
 277            singleton: self.singleton,
 278            capability: self.capability,
 279            replica_id: self.replica_id,
 280            history: self.history.clone(),
 281            title: self.title.clone(),
 282        }
 283    }
 284
 285    pub fn with_title(mut self, title: String) -> Self {
 286        self.title = Some(title);
 287        self
 288    }
 289
 290    pub fn read_only(&self) -> bool {
 291        self.capability == Capability::ReadOnly
 292    }
 293
 294    pub fn singleton(buffer: Model<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 295        let mut this = Self::new(buffer.read(cx).replica_id(), buffer.read(cx).capability());
 296        this.singleton = true;
 297        this.push_excerpts(
 298            buffer,
 299            [ExcerptRange {
 300                context: text::Anchor::MIN..text::Anchor::MAX,
 301                primary: None,
 302            }],
 303            cx,
 304        );
 305        this.snapshot.borrow_mut().singleton = true;
 306        this
 307    }
 308
 309    pub fn replica_id(&self) -> ReplicaId {
 310        self.replica_id
 311    }
 312
 313    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 314        self.sync(cx);
 315        self.snapshot.borrow().clone()
 316    }
 317
 318    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 319        self.sync(cx);
 320        self.snapshot.borrow()
 321    }
 322
 323    pub fn as_singleton(&self) -> Option<Model<Buffer>> {
 324        if self.singleton {
 325            return Some(
 326                self.buffers
 327                    .borrow()
 328                    .values()
 329                    .next()
 330                    .unwrap()
 331                    .buffer
 332                    .clone(),
 333            );
 334        } else {
 335            None
 336        }
 337    }
 338
 339    pub fn is_singleton(&self) -> bool {
 340        self.singleton
 341    }
 342
 343    pub fn subscribe(&mut self) -> Subscription {
 344        self.subscriptions.subscribe()
 345    }
 346
 347    pub fn is_dirty(&self, cx: &AppContext) -> bool {
 348        self.read(cx).is_dirty()
 349    }
 350
 351    pub fn has_conflict(&self, cx: &AppContext) -> bool {
 352        self.read(cx).has_conflict()
 353    }
 354
 355    // The `is_empty` signature doesn't match what clippy expects
 356    #[allow(clippy::len_without_is_empty)]
 357    pub fn len(&self, cx: &AppContext) -> usize {
 358        self.read(cx).len()
 359    }
 360
 361    pub fn is_empty(&self, cx: &AppContext) -> bool {
 362        self.len(cx) != 0
 363    }
 364
 365    pub fn symbols_containing<T: ToOffset>(
 366        &self,
 367        offset: T,
 368        theme: Option<&SyntaxTheme>,
 369        cx: &AppContext,
 370    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 371        self.read(cx).symbols_containing(offset, theme)
 372    }
 373
 374    pub fn edit<I, S, T>(
 375        &mut self,
 376        edits: I,
 377        mut autoindent_mode: Option<AutoindentMode>,
 378        cx: &mut ModelContext<Self>,
 379    ) where
 380        I: IntoIterator<Item = (Range<S>, T)>,
 381        S: ToOffset,
 382        T: Into<Arc<str>>,
 383    {
 384        if self.buffers.borrow().is_empty() {
 385            return;
 386        }
 387
 388        let snapshot = self.read(cx);
 389        let edits = edits.into_iter().map(|(range, new_text)| {
 390            let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 391            if range.start > range.end {
 392                mem::swap(&mut range.start, &mut range.end);
 393            }
 394            (range, new_text)
 395        });
 396
 397        if let Some(buffer) = self.as_singleton() {
 398            return buffer.update(cx, |buffer, cx| {
 399                buffer.edit(edits, autoindent_mode, cx);
 400            });
 401        }
 402
 403        let original_indent_columns = match &mut autoindent_mode {
 404            Some(AutoindentMode::Block {
 405                original_indent_columns,
 406            }) => mem::take(original_indent_columns),
 407            _ => Default::default(),
 408        };
 409
 410        struct BufferEdit {
 411            range: Range<usize>,
 412            new_text: Arc<str>,
 413            is_insertion: bool,
 414            original_indent_column: u32,
 415        }
 416        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 417        let mut edited_excerpt_ids = Vec::new();
 418        let mut cursor = snapshot.excerpts.cursor::<usize>();
 419        for (ix, (range, new_text)) in edits.enumerate() {
 420            let new_text: Arc<str> = new_text.into();
 421            let original_indent_column = original_indent_columns.get(ix).copied().unwrap_or(0);
 422            cursor.seek(&range.start, Bias::Right, &());
 423            if cursor.item().is_none() && range.start == *cursor.start() {
 424                cursor.prev(&());
 425            }
 426            let start_excerpt = cursor.item().expect("start offset out of bounds");
 427            let start_overshoot = range.start - cursor.start();
 428            let buffer_start = start_excerpt
 429                .range
 430                .context
 431                .start
 432                .to_offset(&start_excerpt.buffer)
 433                + start_overshoot;
 434            edited_excerpt_ids.push(start_excerpt.id);
 435
 436            cursor.seek(&range.end, Bias::Right, &());
 437            if cursor.item().is_none() && range.end == *cursor.start() {
 438                cursor.prev(&());
 439            }
 440            let end_excerpt = cursor.item().expect("end offset out of bounds");
 441            let end_overshoot = range.end - cursor.start();
 442            let buffer_end = end_excerpt
 443                .range
 444                .context
 445                .start
 446                .to_offset(&end_excerpt.buffer)
 447                + end_overshoot;
 448
 449            if start_excerpt.id == end_excerpt.id {
 450                buffer_edits
 451                    .entry(start_excerpt.buffer_id)
 452                    .or_insert(Vec::new())
 453                    .push(BufferEdit {
 454                        range: buffer_start..buffer_end,
 455                        new_text,
 456                        is_insertion: true,
 457                        original_indent_column,
 458                    });
 459            } else {
 460                edited_excerpt_ids.push(end_excerpt.id);
 461                let start_excerpt_range = buffer_start
 462                    ..start_excerpt
 463                        .range
 464                        .context
 465                        .end
 466                        .to_offset(&start_excerpt.buffer);
 467                let end_excerpt_range = end_excerpt
 468                    .range
 469                    .context
 470                    .start
 471                    .to_offset(&end_excerpt.buffer)
 472                    ..buffer_end;
 473                buffer_edits
 474                    .entry(start_excerpt.buffer_id)
 475                    .or_insert(Vec::new())
 476                    .push(BufferEdit {
 477                        range: start_excerpt_range,
 478                        new_text: new_text.clone(),
 479                        is_insertion: true,
 480                        original_indent_column,
 481                    });
 482                buffer_edits
 483                    .entry(end_excerpt.buffer_id)
 484                    .or_insert(Vec::new())
 485                    .push(BufferEdit {
 486                        range: end_excerpt_range,
 487                        new_text: new_text.clone(),
 488                        is_insertion: false,
 489                        original_indent_column,
 490                    });
 491
 492                cursor.seek(&range.start, Bias::Right, &());
 493                cursor.next(&());
 494                while let Some(excerpt) = cursor.item() {
 495                    if excerpt.id == end_excerpt.id {
 496                        break;
 497                    }
 498                    buffer_edits
 499                        .entry(excerpt.buffer_id)
 500                        .or_insert(Vec::new())
 501                        .push(BufferEdit {
 502                            range: excerpt.range.context.to_offset(&excerpt.buffer),
 503                            new_text: new_text.clone(),
 504                            is_insertion: false,
 505                            original_indent_column,
 506                        });
 507                    edited_excerpt_ids.push(excerpt.id);
 508                    cursor.next(&());
 509                }
 510            }
 511        }
 512
 513        drop(cursor);
 514        drop(snapshot);
 515        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 516        fn tail(
 517            this: &mut MultiBuffer,
 518            buffer_edits: HashMap<BufferId, Vec<BufferEdit>>,
 519            autoindent_mode: Option<AutoindentMode>,
 520            edited_excerpt_ids: Vec<ExcerptId>,
 521            cx: &mut ModelContext<MultiBuffer>,
 522        ) {
 523            for (buffer_id, mut edits) in buffer_edits {
 524                edits.sort_unstable_by_key(|edit| edit.range.start);
 525                this.buffers.borrow()[&buffer_id]
 526                    .buffer
 527                    .update(cx, |buffer, cx| {
 528                        let mut edits = edits.into_iter().peekable();
 529                        let mut insertions = Vec::new();
 530                        let mut original_indent_columns = Vec::new();
 531                        let mut deletions = Vec::new();
 532                        let empty_str: Arc<str> = "".into();
 533                        while let Some(BufferEdit {
 534                            mut range,
 535                            new_text,
 536                            mut is_insertion,
 537                            original_indent_column,
 538                        }) = edits.next()
 539                        {
 540                            while let Some(BufferEdit {
 541                                range: next_range,
 542                                is_insertion: next_is_insertion,
 543                                ..
 544                            }) = edits.peek()
 545                            {
 546                                if range.end >= next_range.start {
 547                                    range.end = cmp::max(next_range.end, range.end);
 548                                    is_insertion |= *next_is_insertion;
 549                                    edits.next();
 550                                } else {
 551                                    break;
 552                                }
 553                            }
 554
 555                            if is_insertion {
 556                                original_indent_columns.push(original_indent_column);
 557                                insertions.push((
 558                                    buffer.anchor_before(range.start)
 559                                        ..buffer.anchor_before(range.end),
 560                                    new_text.clone(),
 561                                ));
 562                            } else if !range.is_empty() {
 563                                deletions.push((
 564                                    buffer.anchor_before(range.start)
 565                                        ..buffer.anchor_before(range.end),
 566                                    empty_str.clone(),
 567                                ));
 568                            }
 569                        }
 570
 571                        let deletion_autoindent_mode =
 572                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 573                                Some(AutoindentMode::Block {
 574                                    original_indent_columns: Default::default(),
 575                                })
 576                            } else {
 577                                None
 578                            };
 579                        let insertion_autoindent_mode =
 580                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 581                                Some(AutoindentMode::Block {
 582                                    original_indent_columns,
 583                                })
 584                            } else {
 585                                None
 586                            };
 587
 588                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 589                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 590                    })
 591            }
 592
 593            cx.emit(Event::ExcerptsEdited {
 594                ids: edited_excerpt_ids,
 595            });
 596        }
 597        tail(self, buffer_edits, autoindent_mode, edited_excerpt_ids, cx);
 598    }
 599
 600    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 601        self.start_transaction_at(Instant::now(), cx)
 602    }
 603
 604    pub fn start_transaction_at(
 605        &mut self,
 606        now: Instant,
 607        cx: &mut ModelContext<Self>,
 608    ) -> Option<TransactionId> {
 609        if let Some(buffer) = self.as_singleton() {
 610            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 611        }
 612
 613        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 614            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 615        }
 616        self.history.start_transaction(now)
 617    }
 618
 619    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 620        self.end_transaction_at(Instant::now(), cx)
 621    }
 622
 623    pub fn end_transaction_at(
 624        &mut self,
 625        now: Instant,
 626        cx: &mut ModelContext<Self>,
 627    ) -> Option<TransactionId> {
 628        if let Some(buffer) = self.as_singleton() {
 629            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 630        }
 631
 632        let mut buffer_transactions = HashMap::default();
 633        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 634            if let Some(transaction_id) =
 635                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 636            {
 637                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
 638            }
 639        }
 640
 641        if self.history.end_transaction(now, buffer_transactions) {
 642            let transaction_id = self.history.group().unwrap();
 643            Some(transaction_id)
 644        } else {
 645            None
 646        }
 647    }
 648
 649    pub fn merge_transactions(
 650        &mut self,
 651        transaction: TransactionId,
 652        destination: TransactionId,
 653        cx: &mut ModelContext<Self>,
 654    ) {
 655        if let Some(buffer) = self.as_singleton() {
 656            buffer.update(cx, |buffer, _| {
 657                buffer.merge_transactions(transaction, destination)
 658            });
 659        } else {
 660            if let Some(transaction) = self.history.forget(transaction) {
 661                if let Some(destination) = self.history.transaction_mut(destination) {
 662                    for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
 663                        if let Some(destination_buffer_transaction_id) =
 664                            destination.buffer_transactions.get(&buffer_id)
 665                        {
 666                            if let Some(state) = self.buffers.borrow().get(&buffer_id) {
 667                                state.buffer.update(cx, |buffer, _| {
 668                                    buffer.merge_transactions(
 669                                        buffer_transaction_id,
 670                                        *destination_buffer_transaction_id,
 671                                    )
 672                                });
 673                            }
 674                        } else {
 675                            destination
 676                                .buffer_transactions
 677                                .insert(buffer_id, buffer_transaction_id);
 678                        }
 679                    }
 680                }
 681            }
 682        }
 683    }
 684
 685    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 686        self.history.finalize_last_transaction();
 687        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 688            buffer.update(cx, |buffer, _| {
 689                buffer.finalize_last_transaction();
 690            });
 691        }
 692    }
 693
 694    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &mut ModelContext<Self>)
 695    where
 696        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
 697    {
 698        self.history
 699            .push_transaction(buffer_transactions, Instant::now(), cx);
 700        self.history.finalize_last_transaction();
 701    }
 702
 703    pub fn group_until_transaction(
 704        &mut self,
 705        transaction_id: TransactionId,
 706        cx: &mut ModelContext<Self>,
 707    ) {
 708        if let Some(buffer) = self.as_singleton() {
 709            buffer.update(cx, |buffer, _| {
 710                buffer.group_until_transaction(transaction_id)
 711            });
 712        } else {
 713            self.history.group_until(transaction_id);
 714        }
 715    }
 716
 717    pub fn set_active_selections(
 718        &mut self,
 719        selections: &[Selection<Anchor>],
 720        line_mode: bool,
 721        cursor_shape: CursorShape,
 722        cx: &mut ModelContext<Self>,
 723    ) {
 724        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
 725            Default::default();
 726        let snapshot = self.read(cx);
 727        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
 728        for selection in selections {
 729            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
 730            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
 731
 732            cursor.seek(&Some(start_locator), Bias::Left, &());
 733            while let Some(excerpt) = cursor.item() {
 734                if excerpt.locator > *end_locator {
 735                    break;
 736                }
 737
 738                let mut start = excerpt.range.context.start;
 739                let mut end = excerpt.range.context.end;
 740                if excerpt.id == selection.start.excerpt_id {
 741                    start = selection.start.text_anchor;
 742                }
 743                if excerpt.id == selection.end.excerpt_id {
 744                    end = selection.end.text_anchor;
 745                }
 746                selections_by_buffer
 747                    .entry(excerpt.buffer_id)
 748                    .or_default()
 749                    .push(Selection {
 750                        id: selection.id,
 751                        start,
 752                        end,
 753                        reversed: selection.reversed,
 754                        goal: selection.goal,
 755                    });
 756
 757                cursor.next(&());
 758            }
 759        }
 760
 761        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 762            if !selections_by_buffer.contains_key(buffer_id) {
 763                buffer_state
 764                    .buffer
 765                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 766            }
 767        }
 768
 769        for (buffer_id, mut selections) in selections_by_buffer {
 770            self.buffers.borrow()[&buffer_id]
 771                .buffer
 772                .update(cx, |buffer, cx| {
 773                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
 774                    let mut selections = selections.into_iter().peekable();
 775                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 776                        let mut selection = selections.next()?;
 777                        while let Some(next_selection) = selections.peek() {
 778                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
 779                                let next_selection = selections.next().unwrap();
 780                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
 781                                    selection.end = next_selection.end;
 782                                }
 783                            } else {
 784                                break;
 785                            }
 786                        }
 787                        Some(selection)
 788                    }));
 789                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
 790                });
 791        }
 792    }
 793
 794    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 795        for buffer in self.buffers.borrow().values() {
 796            buffer
 797                .buffer
 798                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 799        }
 800    }
 801
 802    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 803        let mut transaction_id = None;
 804        if let Some(buffer) = self.as_singleton() {
 805            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
 806        } else {
 807            while let Some(transaction) = self.history.pop_undo() {
 808                let mut undone = false;
 809                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 810                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 811                        undone |= buffer.update(cx, |buffer, cx| {
 812                            let undo_to = *buffer_transaction_id;
 813                            if let Some(entry) = buffer.peek_undo_stack() {
 814                                *buffer_transaction_id = entry.transaction_id();
 815                            }
 816                            buffer.undo_to_transaction(undo_to, cx)
 817                        });
 818                    }
 819                }
 820
 821                if undone {
 822                    transaction_id = Some(transaction.id);
 823                    break;
 824                }
 825            }
 826        }
 827
 828        if let Some(transaction_id) = transaction_id {
 829            cx.emit(Event::TransactionUndone { transaction_id });
 830        }
 831
 832        transaction_id
 833    }
 834
 835    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 836        if let Some(buffer) = self.as_singleton() {
 837            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 838        }
 839
 840        while let Some(transaction) = self.history.pop_redo() {
 841            let mut redone = false;
 842            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 843                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 844                    redone |= buffer.update(cx, |buffer, cx| {
 845                        let redo_to = *buffer_transaction_id;
 846                        if let Some(entry) = buffer.peek_redo_stack() {
 847                            *buffer_transaction_id = entry.transaction_id();
 848                        }
 849                        buffer.redo_to_transaction(redo_to, cx)
 850                    });
 851                }
 852            }
 853
 854            if redone {
 855                return Some(transaction.id);
 856            }
 857        }
 858
 859        None
 860    }
 861
 862    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut ModelContext<Self>) {
 863        if let Some(buffer) = self.as_singleton() {
 864            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
 865        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
 866            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
 867                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 868                    buffer.update(cx, |buffer, cx| {
 869                        buffer.undo_transaction(*transaction_id, cx)
 870                    });
 871                }
 872            }
 873        }
 874    }
 875
 876    pub fn stream_excerpts_with_context_lines(
 877        &mut self,
 878        buffer: Model<Buffer>,
 879        ranges: Vec<Range<text::Anchor>>,
 880        context_line_count: u32,
 881        cx: &mut ModelContext<Self>,
 882    ) -> mpsc::Receiver<Range<Anchor>> {
 883        let (buffer_id, buffer_snapshot) =
 884            buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
 885
 886        let (mut tx, rx) = mpsc::channel(256);
 887        cx.spawn(move |this, mut cx| async move {
 888            let mut excerpt_ranges = Vec::new();
 889            let mut range_counts = Vec::new();
 890            cx.background_executor()
 891                .scoped(|scope| {
 892                    scope.spawn(async {
 893                        let (ranges, counts) =
 894                            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
 895                        excerpt_ranges = ranges;
 896                        range_counts = counts;
 897                    });
 898                })
 899                .await;
 900
 901            let mut ranges = ranges.into_iter();
 902            let mut range_counts = range_counts.into_iter();
 903            for excerpt_ranges in excerpt_ranges.chunks(100) {
 904                let excerpt_ids = match this.update(&mut cx, |this, cx| {
 905                    this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
 906                }) {
 907                    Ok(excerpt_ids) => excerpt_ids,
 908                    Err(_) => return,
 909                };
 910
 911                for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.by_ref())
 912                {
 913                    for range in ranges.by_ref().take(range_count) {
 914                        let start = Anchor {
 915                            buffer_id: Some(buffer_id),
 916                            excerpt_id: excerpt_id.clone(),
 917                            text_anchor: range.start,
 918                        };
 919                        let end = Anchor {
 920                            buffer_id: Some(buffer_id),
 921                            excerpt_id: excerpt_id.clone(),
 922                            text_anchor: range.end,
 923                        };
 924                        if tx.send(start..end).await.is_err() {
 925                            break;
 926                        }
 927                    }
 928                }
 929            }
 930        })
 931        .detach();
 932
 933        rx
 934    }
 935
 936    pub fn push_excerpts<O>(
 937        &mut self,
 938        buffer: Model<Buffer>,
 939        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 940        cx: &mut ModelContext<Self>,
 941    ) -> Vec<ExcerptId>
 942    where
 943        O: text::ToOffset,
 944    {
 945        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
 946    }
 947
 948    pub fn push_excerpts_with_context_lines<O>(
 949        &mut self,
 950        buffer: Model<Buffer>,
 951        ranges: Vec<Range<O>>,
 952        context_line_count: u32,
 953        cx: &mut ModelContext<Self>,
 954    ) -> Vec<Range<Anchor>>
 955    where
 956        O: text::ToPoint + text::ToOffset,
 957    {
 958        let buffer_id = buffer.read(cx).remote_id();
 959        let buffer_snapshot = buffer.read(cx).snapshot();
 960        let (excerpt_ranges, range_counts) =
 961            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
 962
 963        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
 964
 965        let mut anchor_ranges = Vec::new();
 966        let mut ranges = ranges.into_iter();
 967        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
 968            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
 969                let start = Anchor {
 970                    buffer_id: Some(buffer_id),
 971                    excerpt_id: excerpt_id.clone(),
 972                    text_anchor: buffer_snapshot.anchor_after(range.start),
 973                };
 974                let end = Anchor {
 975                    buffer_id: Some(buffer_id),
 976                    excerpt_id: excerpt_id.clone(),
 977                    text_anchor: buffer_snapshot.anchor_after(range.end),
 978                };
 979                start..end
 980            }))
 981        }
 982        anchor_ranges
 983    }
 984
 985    pub fn insert_excerpts_after<O>(
 986        &mut self,
 987        prev_excerpt_id: ExcerptId,
 988        buffer: Model<Buffer>,
 989        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 990        cx: &mut ModelContext<Self>,
 991    ) -> Vec<ExcerptId>
 992    where
 993        O: text::ToOffset,
 994    {
 995        let mut ids = Vec::new();
 996        let mut next_excerpt_id = self.next_excerpt_id;
 997        self.insert_excerpts_with_ids_after(
 998            prev_excerpt_id,
 999            buffer,
1000            ranges.into_iter().map(|range| {
1001                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1002                ids.push(id);
1003                (id, range)
1004            }),
1005            cx,
1006        );
1007        ids
1008    }
1009
1010    pub fn insert_excerpts_with_ids_after<O>(
1011        &mut self,
1012        prev_excerpt_id: ExcerptId,
1013        buffer: Model<Buffer>,
1014        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1015        cx: &mut ModelContext<Self>,
1016    ) where
1017        O: text::ToOffset,
1018    {
1019        assert_eq!(self.history.transaction_depth, 0);
1020        let mut ranges = ranges.into_iter().peekable();
1021        if ranges.peek().is_none() {
1022            return Default::default();
1023        }
1024
1025        self.sync(cx);
1026
1027        let buffer_id = buffer.read(cx).remote_id();
1028        let buffer_snapshot = buffer.read(cx).snapshot();
1029
1030        let mut buffers = self.buffers.borrow_mut();
1031        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1032            last_version: buffer_snapshot.version().clone(),
1033            last_parse_count: buffer_snapshot.parse_count(),
1034            last_selections_update_count: buffer_snapshot.selections_update_count(),
1035            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
1036            last_file_update_count: buffer_snapshot.file_update_count(),
1037            last_git_diff_update_count: buffer_snapshot.git_diff_update_count(),
1038            excerpts: Default::default(),
1039            _subscriptions: [
1040                cx.observe(&buffer, |_, _, cx| cx.notify()),
1041                cx.subscribe(&buffer, Self::on_buffer_event),
1042            ],
1043            buffer: buffer.clone(),
1044        });
1045
1046        let mut snapshot = self.snapshot.borrow_mut();
1047
1048        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1049        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1050        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1051        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1052        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1053
1054        let edit_start = new_excerpts.summary().text.len;
1055        new_excerpts.update_last(
1056            |excerpt| {
1057                excerpt.has_trailing_newline = true;
1058            },
1059            &(),
1060        );
1061
1062        let next_locator = if let Some(excerpt) = cursor.item() {
1063            excerpt.locator.clone()
1064        } else {
1065            Locator::max()
1066        };
1067
1068        let mut excerpts = Vec::new();
1069        while let Some((id, range)) = ranges.next() {
1070            let locator = Locator::between(&prev_locator, &next_locator);
1071            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1072                buffer_state.excerpts.insert(ix, locator.clone());
1073            }
1074            let range = ExcerptRange {
1075                context: buffer_snapshot.anchor_before(&range.context.start)
1076                    ..buffer_snapshot.anchor_after(&range.context.end),
1077                primary: range.primary.map(|primary| {
1078                    buffer_snapshot.anchor_before(&primary.start)
1079                        ..buffer_snapshot.anchor_after(&primary.end)
1080                }),
1081            };
1082            if id.0 >= self.next_excerpt_id {
1083                self.next_excerpt_id = id.0 + 1;
1084            }
1085            excerpts.push((id, range.clone()));
1086            let excerpt = Excerpt::new(
1087                id,
1088                locator.clone(),
1089                buffer_id,
1090                buffer_snapshot.clone(),
1091                range,
1092                ranges.peek().is_some() || cursor.item().is_some(),
1093            );
1094            new_excerpts.push(excerpt, &());
1095            prev_locator = locator.clone();
1096            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1097        }
1098
1099        let edit_end = new_excerpts.summary().text.len;
1100
1101        let suffix = cursor.suffix(&());
1102        let changed_trailing_excerpt = suffix.is_empty();
1103        new_excerpts.append(suffix, &());
1104        drop(cursor);
1105        snapshot.excerpts = new_excerpts;
1106        snapshot.excerpt_ids = new_excerpt_ids;
1107        if changed_trailing_excerpt {
1108            snapshot.trailing_excerpt_update_count += 1;
1109        }
1110
1111        self.subscriptions.publish_mut([Edit {
1112            old: edit_start..edit_start,
1113            new: edit_start..edit_end,
1114        }]);
1115        cx.emit(Event::Edited {
1116            singleton_buffer_edited: false,
1117        });
1118        cx.emit(Event::ExcerptsAdded {
1119            buffer,
1120            predecessor: prev_excerpt_id,
1121            excerpts,
1122        });
1123        cx.notify();
1124    }
1125
1126    pub fn clear(&mut self, cx: &mut ModelContext<Self>) {
1127        self.sync(cx);
1128        let ids = self.excerpt_ids();
1129        self.buffers.borrow_mut().clear();
1130        let mut snapshot = self.snapshot.borrow_mut();
1131        let prev_len = snapshot.len();
1132        snapshot.excerpts = Default::default();
1133        snapshot.trailing_excerpt_update_count += 1;
1134        snapshot.is_dirty = false;
1135        snapshot.has_conflict = false;
1136
1137        self.subscriptions.publish_mut([Edit {
1138            old: 0..prev_len,
1139            new: 0..0,
1140        }]);
1141        cx.emit(Event::Edited {
1142            singleton_buffer_edited: false,
1143        });
1144        cx.emit(Event::ExcerptsRemoved { ids });
1145        cx.notify();
1146    }
1147
1148    pub fn excerpts_for_buffer(
1149        &self,
1150        buffer: &Model<Buffer>,
1151        cx: &AppContext,
1152    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1153        let mut excerpts = Vec::new();
1154        let snapshot = self.read(cx);
1155        let buffers = self.buffers.borrow();
1156        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1157        for locator in buffers
1158            .get(&buffer.read(cx).remote_id())
1159            .map(|state| &state.excerpts)
1160            .into_iter()
1161            .flatten()
1162        {
1163            cursor.seek_forward(&Some(locator), Bias::Left, &());
1164            if let Some(excerpt) = cursor.item() {
1165                if excerpt.locator == *locator {
1166                    excerpts.push((excerpt.id.clone(), excerpt.range.clone()));
1167                }
1168            }
1169        }
1170
1171        excerpts
1172    }
1173
1174    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1175        self.snapshot
1176            .borrow()
1177            .excerpts
1178            .iter()
1179            .map(|entry| entry.id)
1180            .collect()
1181    }
1182
1183    pub fn excerpt_containing(
1184        &self,
1185        position: impl ToOffset,
1186        cx: &AppContext,
1187    ) -> Option<(ExcerptId, Model<Buffer>, Range<text::Anchor>)> {
1188        let snapshot = self.read(cx);
1189        let position = position.to_offset(&snapshot);
1190
1191        let mut cursor = snapshot.excerpts.cursor::<usize>();
1192        cursor.seek(&position, Bias::Right, &());
1193        cursor
1194            .item()
1195            .or_else(|| snapshot.excerpts.last())
1196            .map(|excerpt| {
1197                (
1198                    excerpt.id.clone(),
1199                    self.buffers
1200                        .borrow()
1201                        .get(&excerpt.buffer_id)
1202                        .unwrap()
1203                        .buffer
1204                        .clone(),
1205                    excerpt.range.context.clone(),
1206                )
1207            })
1208    }
1209
1210    // If point is at the end of the buffer, the last excerpt is returned
1211    pub fn point_to_buffer_offset<T: ToOffset>(
1212        &self,
1213        point: T,
1214        cx: &AppContext,
1215    ) -> Option<(Model<Buffer>, usize, ExcerptId)> {
1216        let snapshot = self.read(cx);
1217        let offset = point.to_offset(&snapshot);
1218        let mut cursor = snapshot.excerpts.cursor::<usize>();
1219        cursor.seek(&offset, Bias::Right, &());
1220        if cursor.item().is_none() {
1221            cursor.prev(&());
1222        }
1223
1224        cursor.item().map(|excerpt| {
1225            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1226            let buffer_point = excerpt_start + offset - *cursor.start();
1227            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1228
1229            (buffer, buffer_point, excerpt.id)
1230        })
1231    }
1232
1233    pub fn range_to_buffer_ranges<T: ToOffset>(
1234        &self,
1235        range: Range<T>,
1236        cx: &AppContext,
1237    ) -> Vec<(Model<Buffer>, Range<usize>, ExcerptId)> {
1238        let snapshot = self.read(cx);
1239        let start = range.start.to_offset(&snapshot);
1240        let end = range.end.to_offset(&snapshot);
1241
1242        let mut result = Vec::new();
1243        let mut cursor = snapshot.excerpts.cursor::<usize>();
1244        cursor.seek(&start, Bias::Right, &());
1245        if cursor.item().is_none() {
1246            cursor.prev(&());
1247        }
1248
1249        while let Some(excerpt) = cursor.item() {
1250            if *cursor.start() > end {
1251                break;
1252            }
1253
1254            let mut end_before_newline = cursor.end(&());
1255            if excerpt.has_trailing_newline {
1256                end_before_newline -= 1;
1257            }
1258            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1259            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
1260            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
1261            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1262            result.push((buffer, start..end, excerpt.id));
1263            cursor.next(&());
1264        }
1265
1266        result
1267    }
1268
1269    pub fn remove_excerpts(
1270        &mut self,
1271        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1272        cx: &mut ModelContext<Self>,
1273    ) {
1274        self.sync(cx);
1275        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1276        if ids.is_empty() {
1277            return;
1278        }
1279
1280        let mut buffers = self.buffers.borrow_mut();
1281        let mut snapshot = self.snapshot.borrow_mut();
1282        let mut new_excerpts = SumTree::new();
1283        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1284        let mut edits = Vec::new();
1285        let mut excerpt_ids = ids.iter().copied().peekable();
1286
1287        while let Some(excerpt_id) = excerpt_ids.next() {
1288            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1289            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1290            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1291
1292            if let Some(mut excerpt) = cursor.item() {
1293                if excerpt.id != excerpt_id {
1294                    continue;
1295                }
1296                let mut old_start = cursor.start().1;
1297
1298                // Skip over the removed excerpt.
1299                'remove_excerpts: loop {
1300                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
1301                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1302                        if buffer_state.excerpts.is_empty() {
1303                            buffers.remove(&excerpt.buffer_id);
1304                        }
1305                    }
1306                    cursor.next(&());
1307
1308                    // Skip over any subsequent excerpts that are also removed.
1309                    while let Some(&next_excerpt_id) = excerpt_ids.peek() {
1310                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1311                        if let Some(next_excerpt) = cursor.item() {
1312                            if next_excerpt.locator == *next_locator {
1313                                excerpt_ids.next();
1314                                excerpt = next_excerpt;
1315                                continue 'remove_excerpts;
1316                            }
1317                        }
1318                        break;
1319                    }
1320
1321                    break;
1322                }
1323
1324                // When removing the last excerpt, remove the trailing newline from
1325                // the previous excerpt.
1326                if cursor.item().is_none() && old_start > 0 {
1327                    old_start -= 1;
1328                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
1329                }
1330
1331                // Push an edit for the removal of this run of excerpts.
1332                let old_end = cursor.start().1;
1333                let new_start = new_excerpts.summary().text.len;
1334                edits.push(Edit {
1335                    old: old_start..old_end,
1336                    new: new_start..new_start,
1337                });
1338            }
1339        }
1340        let suffix = cursor.suffix(&());
1341        let changed_trailing_excerpt = suffix.is_empty();
1342        new_excerpts.append(suffix, &());
1343        drop(cursor);
1344        snapshot.excerpts = new_excerpts;
1345
1346        if changed_trailing_excerpt {
1347            snapshot.trailing_excerpt_update_count += 1;
1348        }
1349
1350        self.subscriptions.publish_mut(edits);
1351        cx.emit(Event::Edited {
1352            singleton_buffer_edited: false,
1353        });
1354        cx.emit(Event::ExcerptsRemoved { ids });
1355        cx.notify();
1356    }
1357
1358    pub fn wait_for_anchors<'a>(
1359        &self,
1360        anchors: impl 'a + Iterator<Item = Anchor>,
1361        cx: &mut ModelContext<Self>,
1362    ) -> impl 'static + Future<Output = Result<()>> {
1363        let borrow = self.buffers.borrow();
1364        let mut error = None;
1365        let mut futures = Vec::new();
1366        for anchor in anchors {
1367            if let Some(buffer_id) = anchor.buffer_id {
1368                if let Some(buffer) = borrow.get(&buffer_id) {
1369                    buffer.buffer.update(cx, |buffer, _| {
1370                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1371                    });
1372                } else {
1373                    error = Some(anyhow!(
1374                        "buffer {buffer_id} is not part of this multi-buffer"
1375                    ));
1376                    break;
1377                }
1378            }
1379        }
1380        async move {
1381            if let Some(error) = error {
1382                Err(error)?;
1383            }
1384            for future in futures {
1385                future.await?;
1386            }
1387            Ok(())
1388        }
1389    }
1390
1391    pub fn text_anchor_for_position<T: ToOffset>(
1392        &self,
1393        position: T,
1394        cx: &AppContext,
1395    ) -> Option<(Model<Buffer>, language::Anchor)> {
1396        let snapshot = self.read(cx);
1397        let anchor = snapshot.anchor_before(position);
1398        let buffer = self
1399            .buffers
1400            .borrow()
1401            .get(&anchor.buffer_id?)?
1402            .buffer
1403            .clone();
1404        Some((buffer, anchor.text_anchor))
1405    }
1406
1407    fn on_buffer_event(
1408        &mut self,
1409        buffer: Model<Buffer>,
1410        event: &language::Event,
1411        cx: &mut ModelContext<Self>,
1412    ) {
1413        cx.emit(match event {
1414            language::Event::Edited => Event::Edited {
1415                singleton_buffer_edited: true,
1416            },
1417            language::Event::DirtyChanged => Event::DirtyChanged,
1418            language::Event::Saved => Event::Saved,
1419            language::Event::FileHandleChanged => Event::FileHandleChanged,
1420            language::Event::Reloaded => Event::Reloaded,
1421            language::Event::DiffBaseChanged => Event::DiffBaseChanged,
1422            language::Event::LanguageChanged => Event::LanguageChanged,
1423            language::Event::Reparsed => Event::Reparsed,
1424            language::Event::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1425            language::Event::Closed => Event::Closed,
1426            language::Event::CapabilityChanged => {
1427                self.capability = buffer.read(cx).capability();
1428                Event::CapabilityChanged
1429            }
1430
1431            //
1432            language::Event::Operation(_) => return,
1433        });
1434    }
1435
1436    pub fn all_buffers(&self) -> HashSet<Model<Buffer>> {
1437        self.buffers
1438            .borrow()
1439            .values()
1440            .map(|state| state.buffer.clone())
1441            .collect()
1442    }
1443
1444    pub fn buffer(&self, buffer_id: BufferId) -> Option<Model<Buffer>> {
1445        self.buffers
1446            .borrow()
1447            .get(&buffer_id)
1448            .map(|state| state.buffer.clone())
1449    }
1450
1451    pub fn is_completion_trigger(&self, position: Anchor, text: &str, cx: &AppContext) -> bool {
1452        let mut chars = text.chars();
1453        let char = if let Some(char) = chars.next() {
1454            char
1455        } else {
1456            return false;
1457        };
1458        if chars.next().is_some() {
1459            return false;
1460        }
1461
1462        let snapshot = self.snapshot(cx);
1463        let position = position.to_offset(&snapshot);
1464        let scope = snapshot.language_scope_at(position);
1465        if char_kind(&scope, char) == CharKind::Word {
1466            return true;
1467        }
1468
1469        let anchor = snapshot.anchor_before(position);
1470        anchor
1471            .buffer_id
1472            .and_then(|buffer_id| {
1473                let buffer = self.buffers.borrow().get(&buffer_id)?.buffer.clone();
1474                Some(
1475                    buffer
1476                        .read(cx)
1477                        .completion_triggers()
1478                        .iter()
1479                        .any(|string| string == text),
1480                )
1481            })
1482            .unwrap_or(false)
1483    }
1484
1485    pub fn language_at<'a, T: ToOffset>(
1486        &self,
1487        point: T,
1488        cx: &'a AppContext,
1489    ) -> Option<Arc<Language>> {
1490        self.point_to_buffer_offset(point, cx)
1491            .and_then(|(buffer, offset, _)| buffer.read(cx).language_at(offset))
1492    }
1493
1494    pub fn settings_at<'a, T: ToOffset>(
1495        &self,
1496        point: T,
1497        cx: &'a AppContext,
1498    ) -> &'a LanguageSettings {
1499        let mut language = None;
1500        let mut file = None;
1501        if let Some((buffer, offset, _)) = self.point_to_buffer_offset(point, cx) {
1502            let buffer = buffer.read(cx);
1503            language = buffer.language_at(offset);
1504            file = buffer.file();
1505        }
1506        language_settings(language.as_ref(), file, cx)
1507    }
1508
1509    pub fn for_each_buffer(&self, mut f: impl FnMut(&Model<Buffer>)) {
1510        self.buffers
1511            .borrow()
1512            .values()
1513            .for_each(|state| f(&state.buffer))
1514    }
1515
1516    pub fn title<'a>(&'a self, cx: &'a AppContext) -> Cow<'a, str> {
1517        if let Some(title) = self.title.as_ref() {
1518            return title.into();
1519        }
1520
1521        if let Some(buffer) = self.as_singleton() {
1522            if let Some(file) = buffer.read(cx).file() {
1523                return file.file_name(cx).to_string_lossy();
1524            }
1525        }
1526
1527        "untitled".into()
1528    }
1529
1530    #[cfg(any(test, feature = "test-support"))]
1531    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1532        self.as_singleton().unwrap().read(cx).is_parsing()
1533    }
1534
1535    fn sync(&self, cx: &AppContext) {
1536        let mut snapshot = self.snapshot.borrow_mut();
1537        let mut excerpts_to_edit = Vec::new();
1538        let mut reparsed = false;
1539        let mut diagnostics_updated = false;
1540        let mut git_diff_updated = false;
1541        let mut is_dirty = false;
1542        let mut has_conflict = false;
1543        let mut edited = false;
1544        let mut buffers = self.buffers.borrow_mut();
1545        for buffer_state in buffers.values_mut() {
1546            let buffer = buffer_state.buffer.read(cx);
1547            let version = buffer.version();
1548            let parse_count = buffer.parse_count();
1549            let selections_update_count = buffer.selections_update_count();
1550            let diagnostics_update_count = buffer.diagnostics_update_count();
1551            let file_update_count = buffer.file_update_count();
1552            let git_diff_update_count = buffer.git_diff_update_count();
1553
1554            let buffer_edited = version.changed_since(&buffer_state.last_version);
1555            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
1556            let buffer_selections_updated =
1557                selections_update_count > buffer_state.last_selections_update_count;
1558            let buffer_diagnostics_updated =
1559                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
1560            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
1561            let buffer_git_diff_updated =
1562                git_diff_update_count > buffer_state.last_git_diff_update_count;
1563            if buffer_edited
1564                || buffer_reparsed
1565                || buffer_selections_updated
1566                || buffer_diagnostics_updated
1567                || buffer_file_updated
1568                || buffer_git_diff_updated
1569            {
1570                buffer_state.last_version = version;
1571                buffer_state.last_parse_count = parse_count;
1572                buffer_state.last_selections_update_count = selections_update_count;
1573                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
1574                buffer_state.last_file_update_count = file_update_count;
1575                buffer_state.last_git_diff_update_count = git_diff_update_count;
1576                excerpts_to_edit.extend(
1577                    buffer_state
1578                        .excerpts
1579                        .iter()
1580                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
1581                );
1582            }
1583
1584            edited |= buffer_edited;
1585            reparsed |= buffer_reparsed;
1586            diagnostics_updated |= buffer_diagnostics_updated;
1587            git_diff_updated |= buffer_git_diff_updated;
1588            is_dirty |= buffer.is_dirty();
1589            has_conflict |= buffer.has_conflict();
1590        }
1591        if edited {
1592            snapshot.edit_count += 1;
1593        }
1594        if reparsed {
1595            snapshot.parse_count += 1;
1596        }
1597        if diagnostics_updated {
1598            snapshot.diagnostics_update_count += 1;
1599        }
1600        if git_diff_updated {
1601            snapshot.git_diff_update_count += 1;
1602        }
1603        snapshot.is_dirty = is_dirty;
1604        snapshot.has_conflict = has_conflict;
1605
1606        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
1607
1608        let mut edits = Vec::new();
1609        let mut new_excerpts = SumTree::new();
1610        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1611
1612        for (locator, buffer, buffer_edited) in excerpts_to_edit {
1613            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1614            let old_excerpt = cursor.item().unwrap();
1615            let buffer = buffer.read(cx);
1616            let buffer_id = buffer.remote_id();
1617
1618            let mut new_excerpt;
1619            if buffer_edited {
1620                edits.extend(
1621                    buffer
1622                        .edits_since_in_range::<usize>(
1623                            old_excerpt.buffer.version(),
1624                            old_excerpt.range.context.clone(),
1625                        )
1626                        .map(|mut edit| {
1627                            let excerpt_old_start = cursor.start().1;
1628                            let excerpt_new_start = new_excerpts.summary().text.len;
1629                            edit.old.start += excerpt_old_start;
1630                            edit.old.end += excerpt_old_start;
1631                            edit.new.start += excerpt_new_start;
1632                            edit.new.end += excerpt_new_start;
1633                            edit
1634                        }),
1635                );
1636
1637                new_excerpt = Excerpt::new(
1638                    old_excerpt.id,
1639                    locator.clone(),
1640                    buffer_id,
1641                    buffer.snapshot(),
1642                    old_excerpt.range.clone(),
1643                    old_excerpt.has_trailing_newline,
1644                );
1645            } else {
1646                new_excerpt = old_excerpt.clone();
1647                new_excerpt.buffer = buffer.snapshot();
1648            }
1649
1650            new_excerpts.push(new_excerpt, &());
1651            cursor.next(&());
1652        }
1653        new_excerpts.append(cursor.suffix(&()), &());
1654
1655        drop(cursor);
1656        snapshot.excerpts = new_excerpts;
1657
1658        self.subscriptions.publish(edits);
1659    }
1660}
1661
1662#[cfg(any(test, feature = "test-support"))]
1663impl MultiBuffer {
1664    pub fn build_simple(text: &str, cx: &mut gpui::AppContext) -> Model<Self> {
1665        let buffer = cx
1666            .new_model(|cx| Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text));
1667        cx.new_model(|cx| Self::singleton(buffer, cx))
1668    }
1669
1670    pub fn build_multi<const COUNT: usize>(
1671        excerpts: [(&str, Vec<Range<Point>>); COUNT],
1672        cx: &mut gpui::AppContext,
1673    ) -> Model<Self> {
1674        let multi = cx.new_model(|_| Self::new(0, Capability::ReadWrite));
1675        for (text, ranges) in excerpts {
1676            let buffer = cx.new_model(|cx| {
1677                Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text)
1678            });
1679            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
1680                context: range,
1681                primary: None,
1682            });
1683            multi.update(cx, |multi, cx| {
1684                multi.push_excerpts(buffer, excerpt_ranges, cx)
1685            });
1686        }
1687
1688        multi
1689    }
1690
1691    pub fn build_from_buffer(buffer: Model<Buffer>, cx: &mut gpui::AppContext) -> Model<Self> {
1692        cx.new_model(|cx| Self::singleton(buffer, cx))
1693    }
1694
1695    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::AppContext) -> Model<Self> {
1696        cx.new_model(|cx| {
1697            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
1698            let mutation_count = rng.gen_range(1..=5);
1699            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
1700            multibuffer
1701        })
1702    }
1703
1704    pub fn randomly_edit(
1705        &mut self,
1706        rng: &mut impl rand::Rng,
1707        edit_count: usize,
1708        cx: &mut ModelContext<Self>,
1709    ) {
1710        use util::RandomCharIter;
1711
1712        let snapshot = self.read(cx);
1713        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
1714        let mut last_end = None;
1715        for _ in 0..edit_count {
1716            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
1717                break;
1718            }
1719
1720            let new_start = last_end.map_or(0, |last_end| last_end + 1);
1721            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
1722            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
1723            last_end = Some(end);
1724
1725            let mut range = start..end;
1726            if rng.gen_bool(0.2) {
1727                mem::swap(&mut range.start, &mut range.end);
1728            }
1729
1730            let new_text_len = rng.gen_range(0..10);
1731            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1732
1733            edits.push((range, new_text.into()));
1734        }
1735        log::info!("mutating multi-buffer with {:?}", edits);
1736        drop(snapshot);
1737
1738        self.edit(edits, None, cx);
1739    }
1740
1741    pub fn randomly_edit_excerpts(
1742        &mut self,
1743        rng: &mut impl rand::Rng,
1744        mutation_count: usize,
1745        cx: &mut ModelContext<Self>,
1746    ) {
1747        use rand::prelude::*;
1748        use std::env;
1749        use util::RandomCharIter;
1750
1751        let max_excerpts = env::var("MAX_EXCERPTS")
1752            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1753            .unwrap_or(5);
1754
1755        let mut buffers = Vec::new();
1756        for _ in 0..mutation_count {
1757            if rng.gen_bool(0.05) {
1758                log::info!("Clearing multi-buffer");
1759                self.clear(cx);
1760                continue;
1761            }
1762
1763            let excerpt_ids = self.excerpt_ids();
1764            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1765                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1766                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1767                    buffers.push(cx.new_model(|cx| {
1768                        Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text)
1769                    }));
1770                    let buffer = buffers.last().unwrap().read(cx);
1771                    log::info!(
1772                        "Creating new buffer {} with text: {:?}",
1773                        buffer.remote_id(),
1774                        buffer.text()
1775                    );
1776                    buffers.last().unwrap().clone()
1777                } else {
1778                    self.buffers
1779                        .borrow()
1780                        .values()
1781                        .choose(rng)
1782                        .unwrap()
1783                        .buffer
1784                        .clone()
1785                };
1786
1787                let buffer = buffer_handle.read(cx);
1788                let buffer_text = buffer.text();
1789                let ranges = (0..rng.gen_range(0..5))
1790                    .map(|_| {
1791                        let end_ix =
1792                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1793                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1794                        ExcerptRange {
1795                            context: start_ix..end_ix,
1796                            primary: None,
1797                        }
1798                    })
1799                    .collect::<Vec<_>>();
1800                log::info!(
1801                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
1802                    buffer_handle.read(cx).remote_id(),
1803                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
1804                    ranges
1805                        .iter()
1806                        .map(|r| &buffer_text[r.context.clone()])
1807                        .collect::<Vec<_>>()
1808                );
1809
1810                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
1811                log::info!("Inserted with ids: {:?}", excerpt_id);
1812            } else {
1813                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1814                let mut excerpts_to_remove = excerpt_ids
1815                    .choose_multiple(rng, remove_count)
1816                    .cloned()
1817                    .collect::<Vec<_>>();
1818                let snapshot = self.snapshot.borrow();
1819                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &*snapshot));
1820                drop(snapshot);
1821                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1822                self.remove_excerpts(excerpts_to_remove, cx);
1823            }
1824        }
1825    }
1826
1827    pub fn randomly_mutate(
1828        &mut self,
1829        rng: &mut impl rand::Rng,
1830        mutation_count: usize,
1831        cx: &mut ModelContext<Self>,
1832    ) {
1833        use rand::prelude::*;
1834
1835        if rng.gen_bool(0.7) || self.singleton {
1836            let buffer = self
1837                .buffers
1838                .borrow()
1839                .values()
1840                .choose(rng)
1841                .map(|state| state.buffer.clone());
1842
1843            if let Some(buffer) = buffer {
1844                buffer.update(cx, |buffer, cx| {
1845                    if rng.gen() {
1846                        buffer.randomly_edit(rng, mutation_count, cx);
1847                    } else {
1848                        buffer.randomly_undo_redo(rng, cx);
1849                    }
1850                });
1851            } else {
1852                self.randomly_edit(rng, mutation_count, cx);
1853            }
1854        } else {
1855            self.randomly_edit_excerpts(rng, mutation_count, cx);
1856        }
1857
1858        self.check_invariants(cx);
1859    }
1860
1861    fn check_invariants(&self, cx: &mut ModelContext<Self>) {
1862        let snapshot = self.read(cx);
1863        let excerpts = snapshot.excerpts.items(&());
1864        let excerpt_ids = snapshot.excerpt_ids.items(&());
1865
1866        for (ix, excerpt) in excerpts.iter().enumerate() {
1867            if ix == 0 {
1868                if excerpt.locator <= Locator::min() {
1869                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
1870                }
1871            } else {
1872                if excerpt.locator <= excerpts[ix - 1].locator {
1873                    panic!("excerpts are out-of-order: {:?}", excerpts);
1874                }
1875            }
1876        }
1877
1878        for (ix, entry) in excerpt_ids.iter().enumerate() {
1879            if ix == 0 {
1880                if entry.id.cmp(&ExcerptId::min(), &*snapshot).is_le() {
1881                    panic!("invalid first excerpt id {:?}", entry.id);
1882                }
1883            } else {
1884                if entry.id <= excerpt_ids[ix - 1].id {
1885                    panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
1886                }
1887            }
1888        }
1889    }
1890}
1891
1892impl EventEmitter<Event> for MultiBuffer {}
1893
1894impl MultiBufferSnapshot {
1895    pub fn text(&self) -> String {
1896        self.chunks(0..self.len(), false)
1897            .map(|chunk| chunk.text)
1898            .collect()
1899    }
1900
1901    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1902        let mut offset = position.to_offset(self);
1903        let mut cursor = self.excerpts.cursor::<usize>();
1904        cursor.seek(&offset, Bias::Left, &());
1905        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1906            let end_before_footer = cursor.start() + excerpt.text_summary.len;
1907            let start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1908            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1909            excerpt.buffer.reversed_chunks_in_range(start..end)
1910        });
1911        iter::from_fn(move || {
1912            if offset == *cursor.start() {
1913                cursor.prev(&());
1914                let excerpt = cursor.item()?;
1915                excerpt_chunks = Some(
1916                    excerpt
1917                        .buffer
1918                        .reversed_chunks_in_range(excerpt.range.context.clone()),
1919                );
1920            }
1921
1922            let excerpt = cursor.item().unwrap();
1923            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1924                offset -= 1;
1925                Some("\n")
1926            } else {
1927                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1928                offset -= chunk.len();
1929                Some(chunk)
1930            }
1931        })
1932        .flat_map(|c| c.chars().rev())
1933    }
1934
1935    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1936        let offset = position.to_offset(self);
1937        self.text_for_range(offset..self.len())
1938            .flat_map(|chunk| chunk.chars())
1939    }
1940
1941    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
1942        self.chunks(range, false).map(|chunk| chunk.text)
1943    }
1944
1945    pub fn is_line_blank(&self, row: u32) -> bool {
1946        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1947            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1948    }
1949
1950    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1951    where
1952        T: ToOffset,
1953    {
1954        let position = position.to_offset(self);
1955        position == self.clip_offset(position, Bias::Left)
1956            && self
1957                .bytes_in_range(position..self.len())
1958                .flatten()
1959                .copied()
1960                .take(needle.len())
1961                .eq(needle.bytes())
1962    }
1963
1964    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1965        let mut start = start.to_offset(self);
1966        let mut end = start;
1967        let mut next_chars = self.chars_at(start).peekable();
1968        let mut prev_chars = self.reversed_chars_at(start).peekable();
1969
1970        let scope = self.language_scope_at(start);
1971        let kind = |c| char_kind(&scope, c);
1972        let word_kind = cmp::max(
1973            prev_chars.peek().copied().map(kind),
1974            next_chars.peek().copied().map(kind),
1975        );
1976
1977        for ch in prev_chars {
1978            if Some(kind(ch)) == word_kind && ch != '\n' {
1979                start -= ch.len_utf8();
1980            } else {
1981                break;
1982            }
1983        }
1984
1985        for ch in next_chars {
1986            if Some(kind(ch)) == word_kind && ch != '\n' {
1987                end += ch.len_utf8();
1988            } else {
1989                break;
1990            }
1991        }
1992
1993        (start..end, word_kind)
1994    }
1995
1996    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
1997        if self.singleton {
1998            self.excerpts
1999                .iter()
2000                .next()
2001                .map(|e| (&e.id, e.buffer_id, &e.buffer))
2002        } else {
2003            None
2004        }
2005    }
2006
2007    pub fn len(&self) -> usize {
2008        self.excerpts.summary().text.len
2009    }
2010
2011    pub fn is_empty(&self) -> bool {
2012        self.excerpts.summary().text.len == 0
2013    }
2014
2015    pub fn max_buffer_row(&self) -> u32 {
2016        self.excerpts.summary().max_buffer_row
2017    }
2018
2019    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
2020        if let Some((_, _, buffer)) = self.as_singleton() {
2021            return buffer.clip_offset(offset, bias);
2022        }
2023
2024        let mut cursor = self.excerpts.cursor::<usize>();
2025        cursor.seek(&offset, Bias::Right, &());
2026        let overshoot = if let Some(excerpt) = cursor.item() {
2027            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2028            let buffer_offset = excerpt
2029                .buffer
2030                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
2031            buffer_offset.saturating_sub(excerpt_start)
2032        } else {
2033            0
2034        };
2035        cursor.start() + overshoot
2036    }
2037
2038    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
2039        if let Some((_, _, buffer)) = self.as_singleton() {
2040            return buffer.clip_point(point, bias);
2041        }
2042
2043        let mut cursor = self.excerpts.cursor::<Point>();
2044        cursor.seek(&point, Bias::Right, &());
2045        let overshoot = if let Some(excerpt) = cursor.item() {
2046            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2047            let buffer_point = excerpt
2048                .buffer
2049                .clip_point(excerpt_start + (point - cursor.start()), bias);
2050            buffer_point.saturating_sub(excerpt_start)
2051        } else {
2052            Point::zero()
2053        };
2054        *cursor.start() + overshoot
2055    }
2056
2057    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
2058        if let Some((_, _, buffer)) = self.as_singleton() {
2059            return buffer.clip_offset_utf16(offset, bias);
2060        }
2061
2062        let mut cursor = self.excerpts.cursor::<OffsetUtf16>();
2063        cursor.seek(&offset, Bias::Right, &());
2064        let overshoot = if let Some(excerpt) = cursor.item() {
2065            let excerpt_start = excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2066            let buffer_offset = excerpt
2067                .buffer
2068                .clip_offset_utf16(excerpt_start + (offset - cursor.start()), bias);
2069            OffsetUtf16(buffer_offset.0.saturating_sub(excerpt_start.0))
2070        } else {
2071            OffsetUtf16(0)
2072        };
2073        *cursor.start() + overshoot
2074    }
2075
2076    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
2077        if let Some((_, _, buffer)) = self.as_singleton() {
2078            return buffer.clip_point_utf16(point, bias);
2079        }
2080
2081        let mut cursor = self.excerpts.cursor::<PointUtf16>();
2082        cursor.seek(&point.0, Bias::Right, &());
2083        let overshoot = if let Some(excerpt) = cursor.item() {
2084            let excerpt_start = excerpt
2085                .buffer
2086                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2087            let buffer_point = excerpt
2088                .buffer
2089                .clip_point_utf16(Unclipped(excerpt_start + (point.0 - cursor.start())), bias);
2090            buffer_point.saturating_sub(excerpt_start)
2091        } else {
2092            PointUtf16::zero()
2093        };
2094        *cursor.start() + overshoot
2095    }
2096
2097    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
2098        let range = range.start.to_offset(self)..range.end.to_offset(self);
2099        let mut excerpts = self.excerpts.cursor::<usize>();
2100        excerpts.seek(&range.start, Bias::Right, &());
2101
2102        let mut chunk = &[][..];
2103        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2104            let mut excerpt_bytes = excerpt
2105                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
2106            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2107            Some(excerpt_bytes)
2108        } else {
2109            None
2110        };
2111        MultiBufferBytes {
2112            range,
2113            excerpts,
2114            excerpt_bytes,
2115            chunk,
2116        }
2117    }
2118
2119    pub fn reversed_bytes_in_range<T: ToOffset>(
2120        &self,
2121        range: Range<T>,
2122    ) -> ReversedMultiBufferBytes {
2123        let range = range.start.to_offset(self)..range.end.to_offset(self);
2124        let mut excerpts = self.excerpts.cursor::<usize>();
2125        excerpts.seek(&range.end, Bias::Left, &());
2126
2127        let mut chunk = &[][..];
2128        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2129            let mut excerpt_bytes = excerpt.reversed_bytes_in_range(
2130                range.start - excerpts.start()..range.end - excerpts.start(),
2131            );
2132            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2133            Some(excerpt_bytes)
2134        } else {
2135            None
2136        };
2137
2138        ReversedMultiBufferBytes {
2139            range,
2140            excerpts,
2141            excerpt_bytes,
2142            chunk,
2143        }
2144    }
2145
2146    pub fn buffer_rows(&self, start_row: u32) -> MultiBufferRows {
2147        let mut result = MultiBufferRows {
2148            buffer_row_range: 0..0,
2149            excerpts: self.excerpts.cursor(),
2150        };
2151        result.seek(start_row);
2152        result
2153    }
2154
2155    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
2156        let range = range.start.to_offset(self)..range.end.to_offset(self);
2157        let mut chunks = MultiBufferChunks {
2158            range: range.clone(),
2159            excerpts: self.excerpts.cursor(),
2160            excerpt_chunks: None,
2161            language_aware,
2162        };
2163        chunks.seek(range.start);
2164        chunks
2165    }
2166
2167    pub fn offset_to_point(&self, offset: usize) -> Point {
2168        if let Some((_, _, buffer)) = self.as_singleton() {
2169            return buffer.offset_to_point(offset);
2170        }
2171
2172        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2173        cursor.seek(&offset, Bias::Right, &());
2174        if let Some(excerpt) = cursor.item() {
2175            let (start_offset, start_point) = cursor.start();
2176            let overshoot = offset - start_offset;
2177            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2178            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2179            let buffer_point = excerpt
2180                .buffer
2181                .offset_to_point(excerpt_start_offset + overshoot);
2182            *start_point + (buffer_point - excerpt_start_point)
2183        } else {
2184            self.excerpts.summary().text.lines
2185        }
2186    }
2187
2188    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
2189        if let Some((_, _, buffer)) = self.as_singleton() {
2190            return buffer.offset_to_point_utf16(offset);
2191        }
2192
2193        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
2194        cursor.seek(&offset, Bias::Right, &());
2195        if let Some(excerpt) = cursor.item() {
2196            let (start_offset, start_point) = cursor.start();
2197            let overshoot = offset - start_offset;
2198            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2199            let excerpt_start_point = excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2200            let buffer_point = excerpt
2201                .buffer
2202                .offset_to_point_utf16(excerpt_start_offset + overshoot);
2203            *start_point + (buffer_point - excerpt_start_point)
2204        } else {
2205            self.excerpts.summary().text.lines_utf16()
2206        }
2207    }
2208
2209    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
2210        if let Some((_, _, buffer)) = self.as_singleton() {
2211            return buffer.point_to_point_utf16(point);
2212        }
2213
2214        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
2215        cursor.seek(&point, Bias::Right, &());
2216        if let Some(excerpt) = cursor.item() {
2217            let (start_offset, start_point) = cursor.start();
2218            let overshoot = point - start_offset;
2219            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2220            let excerpt_start_point_utf16 =
2221                excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2222            let buffer_point = excerpt
2223                .buffer
2224                .point_to_point_utf16(excerpt_start_point + overshoot);
2225            *start_point + (buffer_point - excerpt_start_point_utf16)
2226        } else {
2227            self.excerpts.summary().text.lines_utf16()
2228        }
2229    }
2230
2231    pub fn point_to_offset(&self, point: Point) -> usize {
2232        if let Some((_, _, buffer)) = self.as_singleton() {
2233            return buffer.point_to_offset(point);
2234        }
2235
2236        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
2237        cursor.seek(&point, Bias::Right, &());
2238        if let Some(excerpt) = cursor.item() {
2239            let (start_point, start_offset) = cursor.start();
2240            let overshoot = point - start_point;
2241            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2242            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2243            let buffer_offset = excerpt
2244                .buffer
2245                .point_to_offset(excerpt_start_point + overshoot);
2246            *start_offset + buffer_offset - excerpt_start_offset
2247        } else {
2248            self.excerpts.summary().text.len
2249        }
2250    }
2251
2252    pub fn offset_utf16_to_offset(&self, offset_utf16: OffsetUtf16) -> usize {
2253        if let Some((_, _, buffer)) = self.as_singleton() {
2254            return buffer.offset_utf16_to_offset(offset_utf16);
2255        }
2256
2257        let mut cursor = self.excerpts.cursor::<(OffsetUtf16, usize)>();
2258        cursor.seek(&offset_utf16, Bias::Right, &());
2259        if let Some(excerpt) = cursor.item() {
2260            let (start_offset_utf16, start_offset) = cursor.start();
2261            let overshoot = offset_utf16 - start_offset_utf16;
2262            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2263            let excerpt_start_offset_utf16 =
2264                excerpt.buffer.offset_to_offset_utf16(excerpt_start_offset);
2265            let buffer_offset = excerpt
2266                .buffer
2267                .offset_utf16_to_offset(excerpt_start_offset_utf16 + overshoot);
2268            *start_offset + (buffer_offset - excerpt_start_offset)
2269        } else {
2270            self.excerpts.summary().text.len
2271        }
2272    }
2273
2274    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
2275        if let Some((_, _, buffer)) = self.as_singleton() {
2276            return buffer.offset_to_offset_utf16(offset);
2277        }
2278
2279        let mut cursor = self.excerpts.cursor::<(usize, OffsetUtf16)>();
2280        cursor.seek(&offset, Bias::Right, &());
2281        if let Some(excerpt) = cursor.item() {
2282            let (start_offset, start_offset_utf16) = cursor.start();
2283            let overshoot = offset - start_offset;
2284            let excerpt_start_offset_utf16 =
2285                excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2286            let excerpt_start_offset = excerpt
2287                .buffer
2288                .offset_utf16_to_offset(excerpt_start_offset_utf16);
2289            let buffer_offset_utf16 = excerpt
2290                .buffer
2291                .offset_to_offset_utf16(excerpt_start_offset + overshoot);
2292            *start_offset_utf16 + (buffer_offset_utf16 - excerpt_start_offset_utf16)
2293        } else {
2294            self.excerpts.summary().text.len_utf16
2295        }
2296    }
2297
2298    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
2299        if let Some((_, _, buffer)) = self.as_singleton() {
2300            return buffer.point_utf16_to_offset(point);
2301        }
2302
2303        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
2304        cursor.seek(&point, Bias::Right, &());
2305        if let Some(excerpt) = cursor.item() {
2306            let (start_point, start_offset) = cursor.start();
2307            let overshoot = point - start_point;
2308            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2309            let excerpt_start_point = excerpt
2310                .buffer
2311                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2312            let buffer_offset = excerpt
2313                .buffer
2314                .point_utf16_to_offset(excerpt_start_point + overshoot);
2315            *start_offset + (buffer_offset - excerpt_start_offset)
2316        } else {
2317            self.excerpts.summary().text.len
2318        }
2319    }
2320
2321    pub fn point_to_buffer_offset<T: ToOffset>(
2322        &self,
2323        point: T,
2324    ) -> Option<(&BufferSnapshot, usize)> {
2325        let offset = point.to_offset(self);
2326        let mut cursor = self.excerpts.cursor::<usize>();
2327        cursor.seek(&offset, Bias::Right, &());
2328        if cursor.item().is_none() {
2329            cursor.prev(&());
2330        }
2331
2332        cursor.item().map(|excerpt| {
2333            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2334            let buffer_point = excerpt_start + offset - *cursor.start();
2335            (&excerpt.buffer, buffer_point)
2336        })
2337    }
2338
2339    pub fn suggested_indents(
2340        &self,
2341        rows: impl IntoIterator<Item = u32>,
2342        cx: &AppContext,
2343    ) -> BTreeMap<u32, IndentSize> {
2344        let mut result = BTreeMap::new();
2345
2346        let mut rows_for_excerpt = Vec::new();
2347        let mut cursor = self.excerpts.cursor::<Point>();
2348        let mut rows = rows.into_iter().peekable();
2349        let mut prev_row = u32::MAX;
2350        let mut prev_language_indent_size = IndentSize::default();
2351
2352        while let Some(row) = rows.next() {
2353            cursor.seek(&Point::new(row, 0), Bias::Right, &());
2354            let excerpt = match cursor.item() {
2355                Some(excerpt) => excerpt,
2356                _ => continue,
2357            };
2358
2359            // Retrieve the language and indent size once for each disjoint region being indented.
2360            let single_indent_size = if row.saturating_sub(1) == prev_row {
2361                prev_language_indent_size
2362            } else {
2363                excerpt
2364                    .buffer
2365                    .language_indent_size_at(Point::new(row, 0), cx)
2366            };
2367            prev_language_indent_size = single_indent_size;
2368            prev_row = row;
2369
2370            let start_buffer_row = excerpt.range.context.start.to_point(&excerpt.buffer).row;
2371            let start_multibuffer_row = cursor.start().row;
2372
2373            rows_for_excerpt.push(row);
2374            while let Some(next_row) = rows.peek().copied() {
2375                if cursor.end(&()).row > next_row {
2376                    rows_for_excerpt.push(next_row);
2377                    rows.next();
2378                } else {
2379                    break;
2380                }
2381            }
2382
2383            let buffer_rows = rows_for_excerpt
2384                .drain(..)
2385                .map(|row| start_buffer_row + row - start_multibuffer_row);
2386            let buffer_indents = excerpt
2387                .buffer
2388                .suggested_indents(buffer_rows, single_indent_size);
2389            let multibuffer_indents = buffer_indents
2390                .into_iter()
2391                .map(|(row, indent)| (start_multibuffer_row + row - start_buffer_row, indent));
2392            result.extend(multibuffer_indents);
2393        }
2394
2395        result
2396    }
2397
2398    pub fn indent_size_for_line(&self, row: u32) -> IndentSize {
2399        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
2400            let mut size = buffer.indent_size_for_line(range.start.row);
2401            size.len = size
2402                .len
2403                .min(range.end.column)
2404                .saturating_sub(range.start.column);
2405            size
2406        } else {
2407            IndentSize::spaces(0)
2408        }
2409    }
2410
2411    pub fn prev_non_blank_row(&self, mut row: u32) -> Option<u32> {
2412        while row > 0 {
2413            row -= 1;
2414            if !self.is_line_blank(row) {
2415                return Some(row);
2416            }
2417        }
2418        None
2419    }
2420
2421    pub fn line_len(&self, row: u32) -> u32 {
2422        if let Some((_, range)) = self.buffer_line_for_row(row) {
2423            range.end.column - range.start.column
2424        } else {
2425            0
2426        }
2427    }
2428
2429    pub fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
2430        let mut cursor = self.excerpts.cursor::<Point>();
2431        let point = Point::new(row, 0);
2432        cursor.seek(&point, Bias::Right, &());
2433        if cursor.item().is_none() && *cursor.start() == point {
2434            cursor.prev(&());
2435        }
2436        if let Some(excerpt) = cursor.item() {
2437            let overshoot = row - cursor.start().row;
2438            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2439            let excerpt_end = excerpt.range.context.end.to_point(&excerpt.buffer);
2440            let buffer_row = excerpt_start.row + overshoot;
2441            let line_start = Point::new(buffer_row, 0);
2442            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
2443            return Some((
2444                &excerpt.buffer,
2445                line_start.max(excerpt_start)..line_end.min(excerpt_end),
2446            ));
2447        }
2448        None
2449    }
2450
2451    pub fn max_point(&self) -> Point {
2452        self.text_summary().lines
2453    }
2454
2455    pub fn text_summary(&self) -> TextSummary {
2456        self.excerpts.summary().text.clone()
2457    }
2458
2459    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
2460    where
2461        D: TextDimension,
2462        O: ToOffset,
2463    {
2464        let mut summary = D::default();
2465        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
2466        let mut cursor = self.excerpts.cursor::<usize>();
2467        cursor.seek(&range.start, Bias::Right, &());
2468        if let Some(excerpt) = cursor.item() {
2469            let mut end_before_newline = cursor.end(&());
2470            if excerpt.has_trailing_newline {
2471                end_before_newline -= 1;
2472            }
2473
2474            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2475            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
2476            let end_in_excerpt =
2477                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
2478            summary.add_assign(
2479                &excerpt
2480                    .buffer
2481                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
2482            );
2483
2484            if range.end > end_before_newline {
2485                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
2486            }
2487
2488            cursor.next(&());
2489        }
2490
2491        if range.end > *cursor.start() {
2492            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
2493                &range.end,
2494                Bias::Right,
2495                &(),
2496            )));
2497            if let Some(excerpt) = cursor.item() {
2498                range.end = cmp::max(*cursor.start(), range.end);
2499
2500                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2501                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
2502                summary.add_assign(
2503                    &excerpt
2504                        .buffer
2505                        .text_summary_for_range(excerpt_start..end_in_excerpt),
2506                );
2507            }
2508        }
2509
2510        summary
2511    }
2512
2513    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
2514    where
2515        D: TextDimension + Ord + Sub<D, Output = D>,
2516    {
2517        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2518        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
2519
2520        cursor.seek(locator, Bias::Left, &());
2521        if cursor.item().is_none() {
2522            cursor.next(&());
2523        }
2524
2525        let mut position = D::from_text_summary(&cursor.start().text);
2526        if let Some(excerpt) = cursor.item() {
2527            if excerpt.id == anchor.excerpt_id {
2528                let excerpt_buffer_start =
2529                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2530                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2531                let buffer_position = cmp::min(
2532                    excerpt_buffer_end,
2533                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
2534                );
2535                if buffer_position > excerpt_buffer_start {
2536                    position.add_assign(&(buffer_position - excerpt_buffer_start));
2537                }
2538            }
2539        }
2540        position
2541    }
2542
2543    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
2544    where
2545        D: TextDimension + Ord + Sub<D, Output = D>,
2546        I: 'a + IntoIterator<Item = &'a Anchor>,
2547    {
2548        if let Some((_, _, buffer)) = self.as_singleton() {
2549            return buffer
2550                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
2551                .collect();
2552        }
2553
2554        let mut anchors = anchors.into_iter().peekable();
2555        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2556        let mut summaries = Vec::new();
2557        while let Some(anchor) = anchors.peek() {
2558            let excerpt_id = anchor.excerpt_id;
2559            let excerpt_anchors = iter::from_fn(|| {
2560                let anchor = anchors.peek()?;
2561                if anchor.excerpt_id == excerpt_id {
2562                    Some(&anchors.next().unwrap().text_anchor)
2563                } else {
2564                    None
2565                }
2566            });
2567
2568            let locator = self.excerpt_locator_for_id(excerpt_id);
2569            cursor.seek_forward(locator, Bias::Left, &());
2570            if cursor.item().is_none() {
2571                cursor.next(&());
2572            }
2573
2574            let position = D::from_text_summary(&cursor.start().text);
2575            if let Some(excerpt) = cursor.item() {
2576                if excerpt.id == excerpt_id {
2577                    let excerpt_buffer_start =
2578                        excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2579                    let excerpt_buffer_end =
2580                        excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2581                    summaries.extend(
2582                        excerpt
2583                            .buffer
2584                            .summaries_for_anchors::<D, _>(excerpt_anchors)
2585                            .map(move |summary| {
2586                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
2587                                let mut position = position.clone();
2588                                let excerpt_buffer_start = excerpt_buffer_start.clone();
2589                                if summary > excerpt_buffer_start {
2590                                    position.add_assign(&(summary - excerpt_buffer_start));
2591                                }
2592                                position
2593                            }),
2594                    );
2595                    continue;
2596                }
2597            }
2598
2599            summaries.extend(excerpt_anchors.map(|_| position.clone()));
2600        }
2601
2602        summaries
2603    }
2604
2605    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
2606    where
2607        I: 'a + IntoIterator<Item = &'a Anchor>,
2608    {
2609        let mut anchors = anchors.into_iter().enumerate().peekable();
2610        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
2611        cursor.next(&());
2612
2613        let mut result = Vec::new();
2614
2615        while let Some((_, anchor)) = anchors.peek() {
2616            let old_excerpt_id = anchor.excerpt_id;
2617
2618            // Find the location where this anchor's excerpt should be.
2619            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
2620            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
2621
2622            if cursor.item().is_none() {
2623                cursor.next(&());
2624            }
2625
2626            let next_excerpt = cursor.item();
2627            let prev_excerpt = cursor.prev_item();
2628
2629            // Process all of the anchors for this excerpt.
2630            while let Some((_, anchor)) = anchors.peek() {
2631                if anchor.excerpt_id != old_excerpt_id {
2632                    break;
2633                }
2634                let (anchor_ix, anchor) = anchors.next().unwrap();
2635                let mut anchor = *anchor;
2636
2637                // Leave min and max anchors unchanged if invalid or
2638                // if the old excerpt still exists at this location
2639                let mut kept_position = next_excerpt
2640                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
2641                    || old_excerpt_id == ExcerptId::max()
2642                    || old_excerpt_id == ExcerptId::min();
2643
2644                // If the old excerpt no longer exists at this location, then attempt to
2645                // find an equivalent position for this anchor in an adjacent excerpt.
2646                if !kept_position {
2647                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
2648                        if excerpt.contains(&anchor) {
2649                            anchor.excerpt_id = excerpt.id.clone();
2650                            kept_position = true;
2651                            break;
2652                        }
2653                    }
2654                }
2655
2656                // If there's no adjacent excerpt that contains the anchor's position,
2657                // then report that the anchor has lost its position.
2658                if !kept_position {
2659                    anchor = if let Some(excerpt) = next_excerpt {
2660                        let mut text_anchor = excerpt
2661                            .range
2662                            .context
2663                            .start
2664                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2665                        if text_anchor
2666                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
2667                            .is_gt()
2668                        {
2669                            text_anchor = excerpt.range.context.end;
2670                        }
2671                        Anchor {
2672                            buffer_id: Some(excerpt.buffer_id),
2673                            excerpt_id: excerpt.id.clone(),
2674                            text_anchor,
2675                        }
2676                    } else if let Some(excerpt) = prev_excerpt {
2677                        let mut text_anchor = excerpt
2678                            .range
2679                            .context
2680                            .end
2681                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2682                        if text_anchor
2683                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
2684                            .is_lt()
2685                        {
2686                            text_anchor = excerpt.range.context.start;
2687                        }
2688                        Anchor {
2689                            buffer_id: Some(excerpt.buffer_id),
2690                            excerpt_id: excerpt.id.clone(),
2691                            text_anchor,
2692                        }
2693                    } else if anchor.text_anchor.bias == Bias::Left {
2694                        Anchor::min()
2695                    } else {
2696                        Anchor::max()
2697                    };
2698                }
2699
2700                result.push((anchor_ix, anchor, kept_position));
2701            }
2702        }
2703        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
2704        result
2705    }
2706
2707    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
2708        self.anchor_at(position, Bias::Left)
2709    }
2710
2711    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
2712        self.anchor_at(position, Bias::Right)
2713    }
2714
2715    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
2716        let offset = position.to_offset(self);
2717        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
2718            return Anchor {
2719                buffer_id: Some(buffer_id),
2720                excerpt_id: excerpt_id.clone(),
2721                text_anchor: buffer.anchor_at(offset, bias),
2722            };
2723        }
2724
2725        let mut cursor = self.excerpts.cursor::<(usize, Option<ExcerptId>)>();
2726        cursor.seek(&offset, Bias::Right, &());
2727        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
2728            cursor.prev(&());
2729        }
2730        if let Some(excerpt) = cursor.item() {
2731            let mut overshoot = offset.saturating_sub(cursor.start().0);
2732            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
2733                overshoot -= 1;
2734                bias = Bias::Right;
2735            }
2736
2737            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2738            let text_anchor =
2739                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
2740            Anchor {
2741                buffer_id: Some(excerpt.buffer_id),
2742                excerpt_id: excerpt.id.clone(),
2743                text_anchor,
2744            }
2745        } else if offset == 0 && bias == Bias::Left {
2746            Anchor::min()
2747        } else {
2748            Anchor::max()
2749        }
2750    }
2751
2752    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
2753        let locator = self.excerpt_locator_for_id(excerpt_id);
2754        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
2755        cursor.seek(locator, Bias::Left, &());
2756        if let Some(excerpt) = cursor.item() {
2757            if excerpt.id == excerpt_id {
2758                let text_anchor = excerpt.clip_anchor(text_anchor);
2759                drop(cursor);
2760                return Anchor {
2761                    buffer_id: Some(excerpt.buffer_id),
2762                    excerpt_id,
2763                    text_anchor,
2764                };
2765            }
2766        }
2767        panic!("excerpt not found");
2768    }
2769
2770    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
2771        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
2772            true
2773        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
2774            excerpt.buffer.can_resolve(&anchor.text_anchor)
2775        } else {
2776            false
2777        }
2778    }
2779
2780    pub fn excerpts(
2781        &self,
2782    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
2783        self.excerpts
2784            .iter()
2785            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
2786    }
2787
2788    fn excerpts_for_range<'a, T: ToOffset>(
2789        &'a self,
2790        range: Range<T>,
2791    ) -> impl Iterator<Item = (&'a Excerpt, usize)> + 'a {
2792        let range = range.start.to_offset(self)..range.end.to_offset(self);
2793
2794        let mut cursor = self.excerpts.cursor::<usize>();
2795        cursor.seek(&range.start, Bias::Right, &());
2796        cursor.prev(&());
2797
2798        iter::from_fn(move || {
2799            cursor.next(&());
2800            if cursor.start() < &range.end {
2801                cursor.item().map(|item| (item, *cursor.start()))
2802            } else {
2803                None
2804            }
2805        })
2806    }
2807
2808    pub fn excerpt_boundaries_in_range<R, T>(
2809        &self,
2810        range: R,
2811    ) -> impl Iterator<Item = ExcerptBoundary> + '_
2812    where
2813        R: RangeBounds<T>,
2814        T: ToOffset,
2815    {
2816        let start_offset;
2817        let start = match range.start_bound() {
2818            Bound::Included(start) => {
2819                start_offset = start.to_offset(self);
2820                Bound::Included(start_offset)
2821            }
2822            Bound::Excluded(start) => {
2823                start_offset = start.to_offset(self);
2824                Bound::Excluded(start_offset)
2825            }
2826            Bound::Unbounded => {
2827                start_offset = 0;
2828                Bound::Unbounded
2829            }
2830        };
2831        let end = match range.end_bound() {
2832            Bound::Included(end) => Bound::Included(end.to_offset(self)),
2833            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
2834            Bound::Unbounded => Bound::Unbounded,
2835        };
2836        let bounds = (start, end);
2837
2838        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2839        cursor.seek(&start_offset, Bias::Right, &());
2840        if cursor.item().is_none() {
2841            cursor.prev(&());
2842        }
2843        if !bounds.contains(&cursor.start().0) {
2844            cursor.next(&());
2845        }
2846
2847        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
2848        std::iter::from_fn(move || {
2849            if self.singleton {
2850                None
2851            } else if bounds.contains(&cursor.start().0) {
2852                let excerpt = cursor.item()?;
2853                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
2854                let boundary = ExcerptBoundary {
2855                    id: excerpt.id.clone(),
2856                    row: cursor.start().1.row,
2857                    buffer: excerpt.buffer.clone(),
2858                    range: excerpt.range.clone(),
2859                    starts_new_buffer,
2860                };
2861
2862                prev_buffer_id = Some(excerpt.buffer_id);
2863                cursor.next(&());
2864                Some(boundary)
2865            } else {
2866                None
2867            }
2868        })
2869    }
2870
2871    pub fn edit_count(&self) -> usize {
2872        self.edit_count
2873    }
2874
2875    pub fn parse_count(&self) -> usize {
2876        self.parse_count
2877    }
2878
2879    /// Returns the smallest enclosing bracket ranges containing the given range or
2880    /// None if no brackets contain range or the range is not contained in a single
2881    /// excerpt
2882    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
2883        &self,
2884        range: Range<T>,
2885    ) -> Option<(Range<usize>, Range<usize>)> {
2886        let range = range.start.to_offset(self)..range.end.to_offset(self);
2887
2888        // Get the ranges of the innermost pair of brackets.
2889        let mut result: Option<(Range<usize>, Range<usize>)> = None;
2890
2891        let Some(enclosing_bracket_ranges) = self.enclosing_bracket_ranges(range.clone()) else {
2892            return None;
2893        };
2894
2895        for (open, close) in enclosing_bracket_ranges {
2896            let len = close.end - open.start;
2897
2898            if let Some((existing_open, existing_close)) = &result {
2899                let existing_len = existing_close.end - existing_open.start;
2900                if len > existing_len {
2901                    continue;
2902                }
2903            }
2904
2905            result = Some((open, close));
2906        }
2907
2908        result
2909    }
2910
2911    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
2912    /// not contained in a single excerpt
2913    pub fn enclosing_bracket_ranges<'a, T: ToOffset>(
2914        &'a self,
2915        range: Range<T>,
2916    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + 'a> {
2917        let range = range.start.to_offset(self)..range.end.to_offset(self);
2918
2919        self.bracket_ranges(range.clone()).map(|range_pairs| {
2920            range_pairs
2921                .filter(move |(open, close)| open.start <= range.start && close.end >= range.end)
2922        })
2923    }
2924
2925    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
2926    /// not contained in a single excerpt
2927    pub fn bracket_ranges<'a, T: ToOffset>(
2928        &'a self,
2929        range: Range<T>,
2930    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + 'a> {
2931        let range = range.start.to_offset(self)..range.end.to_offset(self);
2932        let excerpt = self.excerpt_containing(range.clone());
2933        excerpt.map(|(excerpt, excerpt_offset)| {
2934            let excerpt_buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2935            let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2936
2937            let start_in_buffer = excerpt_buffer_start + range.start.saturating_sub(excerpt_offset);
2938            let end_in_buffer = excerpt_buffer_start + range.end.saturating_sub(excerpt_offset);
2939
2940            excerpt
2941                .buffer
2942                .bracket_ranges(start_in_buffer..end_in_buffer)
2943                .filter_map(move |(start_bracket_range, end_bracket_range)| {
2944                    if start_bracket_range.start < excerpt_buffer_start
2945                        || end_bracket_range.end > excerpt_buffer_end
2946                    {
2947                        return None;
2948                    }
2949
2950                    let mut start_bracket_range = start_bracket_range.clone();
2951                    start_bracket_range.start =
2952                        excerpt_offset + (start_bracket_range.start - excerpt_buffer_start);
2953                    start_bracket_range.end =
2954                        excerpt_offset + (start_bracket_range.end - excerpt_buffer_start);
2955
2956                    let mut end_bracket_range = end_bracket_range.clone();
2957                    end_bracket_range.start =
2958                        excerpt_offset + (end_bracket_range.start - excerpt_buffer_start);
2959                    end_bracket_range.end =
2960                        excerpt_offset + (end_bracket_range.end - excerpt_buffer_start);
2961                    Some((start_bracket_range, end_bracket_range))
2962                })
2963        })
2964    }
2965
2966    pub fn redacted_ranges<'a, T: ToOffset>(
2967        &'a self,
2968        range: Range<T>,
2969        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
2970    ) -> impl Iterator<Item = Range<usize>> + 'a {
2971        let range = range.start.to_offset(self)..range.end.to_offset(self);
2972        self.excerpts_for_range(range.clone())
2973            .filter_map(move |(excerpt, excerpt_offset)| {
2974                redaction_enabled(excerpt.buffer.file()).then(move || {
2975                    let excerpt_buffer_start =
2976                        excerpt.range.context.start.to_offset(&excerpt.buffer);
2977
2978                    excerpt
2979                        .buffer
2980                        .redacted_ranges(excerpt.range.context.clone())
2981                        .map(move |mut redacted_range| {
2982                            // Re-base onto the excerpts coordinates in the multibuffer
2983                            redacted_range.start =
2984                                excerpt_offset + (redacted_range.start - excerpt_buffer_start);
2985                            redacted_range.end =
2986                                excerpt_offset + (redacted_range.end - excerpt_buffer_start);
2987
2988                            redacted_range
2989                        })
2990                        .skip_while(move |redacted_range| redacted_range.end < range.start)
2991                        .take_while(move |redacted_range| redacted_range.start < range.end)
2992                })
2993            })
2994            .flatten()
2995    }
2996
2997    pub fn diagnostics_update_count(&self) -> usize {
2998        self.diagnostics_update_count
2999    }
3000
3001    pub fn git_diff_update_count(&self) -> usize {
3002        self.git_diff_update_count
3003    }
3004
3005    pub fn trailing_excerpt_update_count(&self) -> usize {
3006        self.trailing_excerpt_update_count
3007    }
3008
3009    pub fn file_at<'a, T: ToOffset>(&'a self, point: T) -> Option<&'a Arc<dyn File>> {
3010        self.point_to_buffer_offset(point)
3011            .and_then(|(buffer, _)| buffer.file())
3012    }
3013
3014    pub fn language_at<'a, T: ToOffset>(&'a self, point: T) -> Option<&'a Arc<Language>> {
3015        self.point_to_buffer_offset(point)
3016            .and_then(|(buffer, offset)| buffer.language_at(offset))
3017    }
3018
3019    pub fn settings_at<'a, T: ToOffset>(
3020        &'a self,
3021        point: T,
3022        cx: &'a AppContext,
3023    ) -> &'a LanguageSettings {
3024        let mut language = None;
3025        let mut file = None;
3026        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
3027            language = buffer.language_at(offset);
3028            file = buffer.file();
3029        }
3030        language_settings(language, file, cx)
3031    }
3032
3033    pub fn language_scope_at<'a, T: ToOffset>(&'a self, point: T) -> Option<LanguageScope> {
3034        self.point_to_buffer_offset(point)
3035            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
3036    }
3037
3038    pub fn language_indent_size_at<T: ToOffset>(
3039        &self,
3040        position: T,
3041        cx: &AppContext,
3042    ) -> Option<IndentSize> {
3043        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
3044        Some(buffer_snapshot.language_indent_size_at(offset, cx))
3045    }
3046
3047    pub fn is_dirty(&self) -> bool {
3048        self.is_dirty
3049    }
3050
3051    pub fn has_conflict(&self) -> bool {
3052        self.has_conflict
3053    }
3054
3055    pub fn diagnostic_group<'a, O>(
3056        &'a self,
3057        group_id: usize,
3058    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3059    where
3060        O: text::FromAnchor + 'a,
3061    {
3062        self.as_singleton()
3063            .into_iter()
3064            .flat_map(move |(_, _, buffer)| buffer.diagnostic_group(group_id))
3065    }
3066
3067    pub fn diagnostics_in_range<'a, T, O>(
3068        &'a self,
3069        range: Range<T>,
3070        reversed: bool,
3071    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3072    where
3073        T: 'a + ToOffset,
3074        O: 'a + text::FromAnchor + Ord,
3075    {
3076        self.as_singleton()
3077            .into_iter()
3078            .flat_map(move |(_, _, buffer)| {
3079                buffer.diagnostics_in_range(
3080                    range.start.to_offset(self)..range.end.to_offset(self),
3081                    reversed,
3082                )
3083            })
3084    }
3085
3086    pub fn has_git_diffs(&self) -> bool {
3087        for excerpt in self.excerpts.iter() {
3088            if excerpt.buffer.has_git_diff() {
3089                return true;
3090            }
3091        }
3092        false
3093    }
3094
3095    pub fn git_diff_hunks_in_range_rev<'a>(
3096        &'a self,
3097        row_range: Range<u32>,
3098    ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
3099        let mut cursor = self.excerpts.cursor::<Point>();
3100
3101        cursor.seek(&Point::new(row_range.end, 0), Bias::Left, &());
3102        if cursor.item().is_none() {
3103            cursor.prev(&());
3104        }
3105
3106        std::iter::from_fn(move || {
3107            let excerpt = cursor.item()?;
3108            let multibuffer_start = *cursor.start();
3109            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3110            if multibuffer_start.row >= row_range.end {
3111                return None;
3112            }
3113
3114            let mut buffer_start = excerpt.range.context.start;
3115            let mut buffer_end = excerpt.range.context.end;
3116            let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3117            let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3118
3119            if row_range.start > multibuffer_start.row {
3120                let buffer_start_point =
3121                    excerpt_start_point + Point::new(row_range.start - multibuffer_start.row, 0);
3122                buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3123            }
3124
3125            if row_range.end < multibuffer_end.row {
3126                let buffer_end_point =
3127                    excerpt_start_point + Point::new(row_range.end - multibuffer_start.row, 0);
3128                buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3129            }
3130
3131            let buffer_hunks = excerpt
3132                .buffer
3133                .git_diff_hunks_intersecting_range_rev(buffer_start..buffer_end)
3134                .filter_map(move |hunk| {
3135                    let start = multibuffer_start.row
3136                        + hunk
3137                            .buffer_range
3138                            .start
3139                            .saturating_sub(excerpt_start_point.row);
3140                    let end = multibuffer_start.row
3141                        + hunk
3142                            .buffer_range
3143                            .end
3144                            .min(excerpt_end_point.row + 1)
3145                            .saturating_sub(excerpt_start_point.row);
3146
3147                    Some(DiffHunk {
3148                        buffer_range: start..end,
3149                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3150                    })
3151                });
3152
3153            cursor.prev(&());
3154
3155            Some(buffer_hunks)
3156        })
3157        .flatten()
3158    }
3159
3160    pub fn git_diff_hunks_in_range<'a>(
3161        &'a self,
3162        row_range: Range<u32>,
3163    ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
3164        let mut cursor = self.excerpts.cursor::<Point>();
3165
3166        cursor.seek(&Point::new(row_range.start, 0), Bias::Right, &());
3167
3168        std::iter::from_fn(move || {
3169            let excerpt = cursor.item()?;
3170            let multibuffer_start = *cursor.start();
3171            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3172            if multibuffer_start.row >= row_range.end {
3173                return None;
3174            }
3175
3176            let mut buffer_start = excerpt.range.context.start;
3177            let mut buffer_end = excerpt.range.context.end;
3178            let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3179            let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3180
3181            if row_range.start > multibuffer_start.row {
3182                let buffer_start_point =
3183                    excerpt_start_point + Point::new(row_range.start - multibuffer_start.row, 0);
3184                buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3185            }
3186
3187            if row_range.end < multibuffer_end.row {
3188                let buffer_end_point =
3189                    excerpt_start_point + Point::new(row_range.end - multibuffer_start.row, 0);
3190                buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3191            }
3192
3193            let buffer_hunks = excerpt
3194                .buffer
3195                .git_diff_hunks_intersecting_range(buffer_start..buffer_end)
3196                .filter_map(move |hunk| {
3197                    let start = multibuffer_start.row
3198                        + hunk
3199                            .buffer_range
3200                            .start
3201                            .saturating_sub(excerpt_start_point.row);
3202                    let end = multibuffer_start.row
3203                        + hunk
3204                            .buffer_range
3205                            .end
3206                            .min(excerpt_end_point.row + 1)
3207                            .saturating_sub(excerpt_start_point.row);
3208
3209                    Some(DiffHunk {
3210                        buffer_range: start..end,
3211                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3212                    })
3213                });
3214
3215            cursor.next(&());
3216
3217            Some(buffer_hunks)
3218        })
3219        .flatten()
3220    }
3221
3222    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
3223        let range = range.start.to_offset(self)..range.end.to_offset(self);
3224
3225        self.excerpt_containing(range.clone())
3226            .and_then(|(excerpt, excerpt_offset)| {
3227                let excerpt_buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
3228                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3229
3230                let start_in_buffer =
3231                    excerpt_buffer_start + range.start.saturating_sub(excerpt_offset);
3232                let end_in_buffer = excerpt_buffer_start + range.end.saturating_sub(excerpt_offset);
3233                let mut ancestor_buffer_range = excerpt
3234                    .buffer
3235                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
3236                ancestor_buffer_range.start =
3237                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
3238                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
3239
3240                let start = excerpt_offset + (ancestor_buffer_range.start - excerpt_buffer_start);
3241                let end = excerpt_offset + (ancestor_buffer_range.end - excerpt_buffer_start);
3242                Some(start..end)
3243            })
3244    }
3245
3246    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
3247        let (excerpt_id, _, buffer) = self.as_singleton()?;
3248        let outline = buffer.outline(theme)?;
3249        Some(Outline::new(
3250            outline
3251                .items
3252                .into_iter()
3253                .map(|item| OutlineItem {
3254                    depth: item.depth,
3255                    range: self.anchor_in_excerpt(excerpt_id.clone(), item.range.start)
3256                        ..self.anchor_in_excerpt(excerpt_id.clone(), item.range.end),
3257                    text: item.text,
3258                    highlight_ranges: item.highlight_ranges,
3259                    name_ranges: item.name_ranges,
3260                })
3261                .collect(),
3262        ))
3263    }
3264
3265    pub fn symbols_containing<T: ToOffset>(
3266        &self,
3267        offset: T,
3268        theme: Option<&SyntaxTheme>,
3269    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
3270        let anchor = self.anchor_before(offset);
3271        let excerpt_id = anchor.excerpt_id;
3272        let excerpt = self.excerpt(excerpt_id)?;
3273        Some((
3274            excerpt.buffer_id,
3275            excerpt
3276                .buffer
3277                .symbols_containing(anchor.text_anchor, theme)
3278                .into_iter()
3279                .flatten()
3280                .map(|item| OutlineItem {
3281                    depth: item.depth,
3282                    range: self.anchor_in_excerpt(excerpt_id, item.range.start)
3283                        ..self.anchor_in_excerpt(excerpt_id, item.range.end),
3284                    text: item.text,
3285                    highlight_ranges: item.highlight_ranges,
3286                    name_ranges: item.name_ranges,
3287                })
3288                .collect(),
3289        ))
3290    }
3291
3292    fn excerpt_locator_for_id<'a>(&'a self, id: ExcerptId) -> &'a Locator {
3293        if id == ExcerptId::min() {
3294            Locator::min_ref()
3295        } else if id == ExcerptId::max() {
3296            Locator::max_ref()
3297        } else {
3298            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3299            cursor.seek(&id, Bias::Left, &());
3300            if let Some(entry) = cursor.item() {
3301                if entry.id == id {
3302                    return &entry.locator;
3303                }
3304            }
3305            panic!("invalid excerpt id {:?}", id)
3306        }
3307    }
3308
3309    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
3310        Some(self.excerpt(excerpt_id)?.buffer_id)
3311    }
3312
3313    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
3314        Some(&self.excerpt(excerpt_id)?.buffer)
3315    }
3316
3317    fn excerpt<'a>(&'a self, excerpt_id: ExcerptId) -> Option<&'a Excerpt> {
3318        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
3319        let locator = self.excerpt_locator_for_id(excerpt_id);
3320        cursor.seek(&Some(locator), Bias::Left, &());
3321        if let Some(excerpt) = cursor.item() {
3322            if excerpt.id == excerpt_id {
3323                return Some(excerpt);
3324            }
3325        }
3326        None
3327    }
3328
3329    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
3330    fn excerpt_containing<'a, T: ToOffset>(
3331        &'a self,
3332        range: Range<T>,
3333    ) -> Option<(&'a Excerpt, usize)> {
3334        let range = range.start.to_offset(self)..range.end.to_offset(self);
3335
3336        let mut cursor = self.excerpts.cursor::<usize>();
3337        cursor.seek(&range.start, Bias::Right, &());
3338        let start_excerpt = cursor.item();
3339
3340        if range.start == range.end {
3341            return start_excerpt.map(|excerpt| (excerpt, *cursor.start()));
3342        }
3343
3344        cursor.seek(&range.end, Bias::Right, &());
3345        let end_excerpt = cursor.item();
3346
3347        start_excerpt
3348            .zip(end_excerpt)
3349            .and_then(|(start_excerpt, end_excerpt)| {
3350                if start_excerpt.id != end_excerpt.id {
3351                    return None;
3352                }
3353
3354                Some((start_excerpt, *cursor.start()))
3355            })
3356    }
3357
3358    pub fn remote_selections_in_range<'a>(
3359        &'a self,
3360        range: &'a Range<Anchor>,
3361    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
3362        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
3363        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
3364        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
3365        cursor.seek(start_locator, Bias::Left, &());
3366        cursor
3367            .take_while(move |excerpt| excerpt.locator <= *end_locator)
3368            .flat_map(move |excerpt| {
3369                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
3370                if excerpt.id == range.start.excerpt_id {
3371                    query_range.start = range.start.text_anchor;
3372                }
3373                if excerpt.id == range.end.excerpt_id {
3374                    query_range.end = range.end.text_anchor;
3375                }
3376
3377                excerpt
3378                    .buffer
3379                    .remote_selections_in_range(query_range)
3380                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
3381                        selections.map(move |selection| {
3382                            let mut start = Anchor {
3383                                buffer_id: Some(excerpt.buffer_id),
3384                                excerpt_id: excerpt.id.clone(),
3385                                text_anchor: selection.start,
3386                            };
3387                            let mut end = Anchor {
3388                                buffer_id: Some(excerpt.buffer_id),
3389                                excerpt_id: excerpt.id.clone(),
3390                                text_anchor: selection.end,
3391                            };
3392                            if range.start.cmp(&start, self).is_gt() {
3393                                start = range.start.clone();
3394                            }
3395                            if range.end.cmp(&end, self).is_lt() {
3396                                end = range.end.clone();
3397                            }
3398
3399                            (
3400                                replica_id,
3401                                line_mode,
3402                                cursor_shape,
3403                                Selection {
3404                                    id: selection.id,
3405                                    start,
3406                                    end,
3407                                    reversed: selection.reversed,
3408                                    goal: selection.goal,
3409                                },
3410                            )
3411                        })
3412                    })
3413            })
3414    }
3415}
3416
3417#[cfg(any(test, feature = "test-support"))]
3418impl MultiBufferSnapshot {
3419    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
3420        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
3421        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
3422        start..end
3423    }
3424}
3425
3426impl History {
3427    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
3428        self.transaction_depth += 1;
3429        if self.transaction_depth == 1 {
3430            let id = self.next_transaction_id.tick();
3431            self.undo_stack.push(Transaction {
3432                id,
3433                buffer_transactions: Default::default(),
3434                first_edit_at: now,
3435                last_edit_at: now,
3436                suppress_grouping: false,
3437            });
3438            Some(id)
3439        } else {
3440            None
3441        }
3442    }
3443
3444    fn end_transaction(
3445        &mut self,
3446        now: Instant,
3447        buffer_transactions: HashMap<BufferId, TransactionId>,
3448    ) -> bool {
3449        assert_ne!(self.transaction_depth, 0);
3450        self.transaction_depth -= 1;
3451        if self.transaction_depth == 0 {
3452            if buffer_transactions.is_empty() {
3453                self.undo_stack.pop();
3454                false
3455            } else {
3456                self.redo_stack.clear();
3457                let transaction = self.undo_stack.last_mut().unwrap();
3458                transaction.last_edit_at = now;
3459                for (buffer_id, transaction_id) in buffer_transactions {
3460                    transaction
3461                        .buffer_transactions
3462                        .entry(buffer_id)
3463                        .or_insert(transaction_id);
3464                }
3465                true
3466            }
3467        } else {
3468            false
3469        }
3470    }
3471
3472    fn push_transaction<'a, T>(
3473        &mut self,
3474        buffer_transactions: T,
3475        now: Instant,
3476        cx: &mut ModelContext<MultiBuffer>,
3477    ) where
3478        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
3479    {
3480        assert_eq!(self.transaction_depth, 0);
3481        let transaction = Transaction {
3482            id: self.next_transaction_id.tick(),
3483            buffer_transactions: buffer_transactions
3484                .into_iter()
3485                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
3486                .collect(),
3487            first_edit_at: now,
3488            last_edit_at: now,
3489            suppress_grouping: false,
3490        };
3491        if !transaction.buffer_transactions.is_empty() {
3492            self.undo_stack.push(transaction);
3493            self.redo_stack.clear();
3494        }
3495    }
3496
3497    fn finalize_last_transaction(&mut self) {
3498        if let Some(transaction) = self.undo_stack.last_mut() {
3499            transaction.suppress_grouping = true;
3500        }
3501    }
3502
3503    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
3504        if let Some(ix) = self
3505            .undo_stack
3506            .iter()
3507            .rposition(|transaction| transaction.id == transaction_id)
3508        {
3509            Some(self.undo_stack.remove(ix))
3510        } else if let Some(ix) = self
3511            .redo_stack
3512            .iter()
3513            .rposition(|transaction| transaction.id == transaction_id)
3514        {
3515            Some(self.redo_stack.remove(ix))
3516        } else {
3517            None
3518        }
3519    }
3520
3521    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
3522        self.undo_stack
3523            .iter_mut()
3524            .find(|transaction| transaction.id == transaction_id)
3525            .or_else(|| {
3526                self.redo_stack
3527                    .iter_mut()
3528                    .find(|transaction| transaction.id == transaction_id)
3529            })
3530    }
3531
3532    fn pop_undo(&mut self) -> Option<&mut Transaction> {
3533        assert_eq!(self.transaction_depth, 0);
3534        if let Some(transaction) = self.undo_stack.pop() {
3535            self.redo_stack.push(transaction);
3536            self.redo_stack.last_mut()
3537        } else {
3538            None
3539        }
3540    }
3541
3542    fn pop_redo(&mut self) -> Option<&mut Transaction> {
3543        assert_eq!(self.transaction_depth, 0);
3544        if let Some(transaction) = self.redo_stack.pop() {
3545            self.undo_stack.push(transaction);
3546            self.undo_stack.last_mut()
3547        } else {
3548            None
3549        }
3550    }
3551
3552    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
3553        let ix = self
3554            .undo_stack
3555            .iter()
3556            .rposition(|transaction| transaction.id == transaction_id)?;
3557        let transaction = self.undo_stack.remove(ix);
3558        self.redo_stack.push(transaction);
3559        self.redo_stack.last()
3560    }
3561
3562    fn group(&mut self) -> Option<TransactionId> {
3563        let mut count = 0;
3564        let mut transactions = self.undo_stack.iter();
3565        if let Some(mut transaction) = transactions.next_back() {
3566            while let Some(prev_transaction) = transactions.next_back() {
3567                if !prev_transaction.suppress_grouping
3568                    && transaction.first_edit_at - prev_transaction.last_edit_at
3569                        <= self.group_interval
3570                {
3571                    transaction = prev_transaction;
3572                    count += 1;
3573                } else {
3574                    break;
3575                }
3576            }
3577        }
3578        self.group_trailing(count)
3579    }
3580
3581    fn group_until(&mut self, transaction_id: TransactionId) {
3582        let mut count = 0;
3583        for transaction in self.undo_stack.iter().rev() {
3584            if transaction.id == transaction_id {
3585                self.group_trailing(count);
3586                break;
3587            } else if transaction.suppress_grouping {
3588                break;
3589            } else {
3590                count += 1;
3591            }
3592        }
3593    }
3594
3595    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
3596        let new_len = self.undo_stack.len() - n;
3597        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
3598        if let Some(last_transaction) = transactions_to_keep.last_mut() {
3599            if let Some(transaction) = transactions_to_merge.last() {
3600                last_transaction.last_edit_at = transaction.last_edit_at;
3601            }
3602            for to_merge in transactions_to_merge {
3603                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
3604                    last_transaction
3605                        .buffer_transactions
3606                        .entry(*buffer_id)
3607                        .or_insert(*transaction_id);
3608                }
3609            }
3610        }
3611
3612        self.undo_stack.truncate(new_len);
3613        self.undo_stack.last().map(|t| t.id)
3614    }
3615}
3616
3617impl Excerpt {
3618    fn new(
3619        id: ExcerptId,
3620        locator: Locator,
3621        buffer_id: BufferId,
3622        buffer: BufferSnapshot,
3623        range: ExcerptRange<text::Anchor>,
3624        has_trailing_newline: bool,
3625    ) -> Self {
3626        Excerpt {
3627            id,
3628            locator,
3629            max_buffer_row: range.context.end.to_point(&buffer).row,
3630            text_summary: buffer
3631                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
3632            buffer_id,
3633            buffer,
3634            range,
3635            has_trailing_newline,
3636        }
3637    }
3638
3639    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
3640        let content_start = self.range.context.start.to_offset(&self.buffer);
3641        let chunks_start = content_start + range.start;
3642        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
3643
3644        let footer_height = if self.has_trailing_newline
3645            && range.start <= self.text_summary.len
3646            && range.end > self.text_summary.len
3647        {
3648            1
3649        } else {
3650            0
3651        };
3652
3653        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
3654
3655        ExcerptChunks {
3656            content_chunks,
3657            footer_height,
3658        }
3659    }
3660
3661    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
3662        let content_start = self.range.context.start.to_offset(&self.buffer);
3663        let bytes_start = content_start + range.start;
3664        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
3665        let footer_height = if self.has_trailing_newline
3666            && range.start <= self.text_summary.len
3667            && range.end > self.text_summary.len
3668        {
3669            1
3670        } else {
3671            0
3672        };
3673        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
3674
3675        ExcerptBytes {
3676            content_bytes,
3677            footer_height,
3678        }
3679    }
3680
3681    fn reversed_bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
3682        let content_start = self.range.context.start.to_offset(&self.buffer);
3683        let bytes_start = content_start + range.start;
3684        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
3685        let footer_height = if self.has_trailing_newline
3686            && range.start <= self.text_summary.len
3687            && range.end > self.text_summary.len
3688        {
3689            1
3690        } else {
3691            0
3692        };
3693        let content_bytes = self.buffer.reversed_bytes_in_range(bytes_start..bytes_end);
3694
3695        ExcerptBytes {
3696            content_bytes,
3697            footer_height,
3698        }
3699    }
3700
3701    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
3702        if text_anchor
3703            .cmp(&self.range.context.start, &self.buffer)
3704            .is_lt()
3705        {
3706            self.range.context.start
3707        } else if text_anchor
3708            .cmp(&self.range.context.end, &self.buffer)
3709            .is_gt()
3710        {
3711            self.range.context.end
3712        } else {
3713            text_anchor
3714        }
3715    }
3716
3717    fn contains(&self, anchor: &Anchor) -> bool {
3718        Some(self.buffer_id) == anchor.buffer_id
3719            && self
3720                .range
3721                .context
3722                .start
3723                .cmp(&anchor.text_anchor, &self.buffer)
3724                .is_le()
3725            && self
3726                .range
3727                .context
3728                .end
3729                .cmp(&anchor.text_anchor, &self.buffer)
3730                .is_ge()
3731    }
3732}
3733
3734impl ExcerptId {
3735    pub fn min() -> Self {
3736        Self(0)
3737    }
3738
3739    pub fn max() -> Self {
3740        Self(usize::MAX)
3741    }
3742
3743    pub fn to_proto(&self) -> u64 {
3744        self.0 as _
3745    }
3746
3747    pub fn from_proto(proto: u64) -> Self {
3748        Self(proto as _)
3749    }
3750
3751    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
3752        let a = snapshot.excerpt_locator_for_id(*self);
3753        let b = snapshot.excerpt_locator_for_id(*other);
3754        a.cmp(b).then_with(|| self.0.cmp(&other.0))
3755    }
3756}
3757
3758impl Into<usize> for ExcerptId {
3759    fn into(self) -> usize {
3760        self.0
3761    }
3762}
3763
3764impl fmt::Debug for Excerpt {
3765    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3766        f.debug_struct("Excerpt")
3767            .field("id", &self.id)
3768            .field("locator", &self.locator)
3769            .field("buffer_id", &self.buffer_id)
3770            .field("range", &self.range)
3771            .field("text_summary", &self.text_summary)
3772            .field("has_trailing_newline", &self.has_trailing_newline)
3773            .finish()
3774    }
3775}
3776
3777impl sum_tree::Item for Excerpt {
3778    type Summary = ExcerptSummary;
3779
3780    fn summary(&self) -> Self::Summary {
3781        let mut text = self.text_summary.clone();
3782        if self.has_trailing_newline {
3783            text += TextSummary::from("\n");
3784        }
3785        ExcerptSummary {
3786            excerpt_id: self.id,
3787            excerpt_locator: self.locator.clone(),
3788            max_buffer_row: self.max_buffer_row,
3789            text,
3790        }
3791    }
3792}
3793
3794impl sum_tree::Item for ExcerptIdMapping {
3795    type Summary = ExcerptId;
3796
3797    fn summary(&self) -> Self::Summary {
3798        self.id
3799    }
3800}
3801
3802impl sum_tree::KeyedItem for ExcerptIdMapping {
3803    type Key = ExcerptId;
3804
3805    fn key(&self) -> Self::Key {
3806        self.id
3807    }
3808}
3809
3810impl sum_tree::Summary for ExcerptId {
3811    type Context = ();
3812
3813    fn add_summary(&mut self, other: &Self, _: &()) {
3814        *self = *other;
3815    }
3816}
3817
3818impl sum_tree::Summary for ExcerptSummary {
3819    type Context = ();
3820
3821    fn add_summary(&mut self, summary: &Self, _: &()) {
3822        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
3823        self.excerpt_locator = summary.excerpt_locator.clone();
3824        self.text.add_summary(&summary.text, &());
3825        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
3826    }
3827}
3828
3829impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
3830    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3831        *self += &summary.text;
3832    }
3833}
3834
3835impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
3836    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3837        *self += summary.text.len;
3838    }
3839}
3840
3841impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
3842    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
3843        Ord::cmp(self, &cursor_location.text.len)
3844    }
3845}
3846
3847impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
3848    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
3849        Ord::cmp(&Some(self), cursor_location)
3850    }
3851}
3852
3853impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
3854    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
3855        Ord::cmp(self, &cursor_location.excerpt_locator)
3856    }
3857}
3858
3859impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for OffsetUtf16 {
3860    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3861        *self += summary.text.len_utf16;
3862    }
3863}
3864
3865impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
3866    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3867        *self += summary.text.lines;
3868    }
3869}
3870
3871impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
3872    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3873        *self += summary.text.lines_utf16()
3874    }
3875}
3876
3877impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
3878    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3879        *self = Some(&summary.excerpt_locator);
3880    }
3881}
3882
3883impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
3884    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3885        *self = Some(summary.excerpt_id);
3886    }
3887}
3888
3889impl<'a> MultiBufferRows<'a> {
3890    pub fn seek(&mut self, row: u32) {
3891        self.buffer_row_range = 0..0;
3892
3893        self.excerpts
3894            .seek_forward(&Point::new(row, 0), Bias::Right, &());
3895        if self.excerpts.item().is_none() {
3896            self.excerpts.prev(&());
3897
3898            if self.excerpts.item().is_none() && row == 0 {
3899                self.buffer_row_range = 0..1;
3900                return;
3901            }
3902        }
3903
3904        if let Some(excerpt) = self.excerpts.item() {
3905            let overshoot = row - self.excerpts.start().row;
3906            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
3907            self.buffer_row_range.start = excerpt_start + overshoot;
3908            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
3909        }
3910    }
3911}
3912
3913impl<'a> Iterator for MultiBufferRows<'a> {
3914    type Item = Option<u32>;
3915
3916    fn next(&mut self) -> Option<Self::Item> {
3917        loop {
3918            if !self.buffer_row_range.is_empty() {
3919                let row = Some(self.buffer_row_range.start);
3920                self.buffer_row_range.start += 1;
3921                return Some(row);
3922            }
3923            self.excerpts.item()?;
3924            self.excerpts.next(&());
3925            let excerpt = self.excerpts.item()?;
3926            self.buffer_row_range.start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
3927            self.buffer_row_range.end =
3928                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
3929        }
3930    }
3931}
3932
3933impl<'a> MultiBufferChunks<'a> {
3934    pub fn offset(&self) -> usize {
3935        self.range.start
3936    }
3937
3938    pub fn seek(&mut self, offset: usize) {
3939        self.range.start = offset;
3940        self.excerpts.seek(&offset, Bias::Right, &());
3941        if let Some(excerpt) = self.excerpts.item() {
3942            self.excerpt_chunks = Some(excerpt.chunks_in_range(
3943                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
3944                self.language_aware,
3945            ));
3946        } else {
3947            self.excerpt_chunks = None;
3948        }
3949    }
3950}
3951
3952impl<'a> Iterator for MultiBufferChunks<'a> {
3953    type Item = Chunk<'a>;
3954
3955    fn next(&mut self) -> Option<Self::Item> {
3956        if self.range.is_empty() {
3957            None
3958        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
3959            self.range.start += chunk.text.len();
3960            Some(chunk)
3961        } else {
3962            self.excerpts.next(&());
3963            let excerpt = self.excerpts.item()?;
3964            self.excerpt_chunks = Some(excerpt.chunks_in_range(
3965                0..self.range.end - self.excerpts.start(),
3966                self.language_aware,
3967            ));
3968            self.next()
3969        }
3970    }
3971}
3972
3973impl<'a> MultiBufferBytes<'a> {
3974    fn consume(&mut self, len: usize) {
3975        self.range.start += len;
3976        self.chunk = &self.chunk[len..];
3977
3978        if !self.range.is_empty() && self.chunk.is_empty() {
3979            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
3980                self.chunk = chunk;
3981            } else {
3982                self.excerpts.next(&());
3983                if let Some(excerpt) = self.excerpts.item() {
3984                    let mut excerpt_bytes =
3985                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
3986                    self.chunk = excerpt_bytes.next().unwrap();
3987                    self.excerpt_bytes = Some(excerpt_bytes);
3988                }
3989            }
3990        }
3991    }
3992}
3993
3994impl<'a> Iterator for MultiBufferBytes<'a> {
3995    type Item = &'a [u8];
3996
3997    fn next(&mut self) -> Option<Self::Item> {
3998        let chunk = self.chunk;
3999        if chunk.is_empty() {
4000            None
4001        } else {
4002            self.consume(chunk.len());
4003            Some(chunk)
4004        }
4005    }
4006}
4007
4008impl<'a> io::Read for MultiBufferBytes<'a> {
4009    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4010        let len = cmp::min(buf.len(), self.chunk.len());
4011        buf[..len].copy_from_slice(&self.chunk[..len]);
4012        if len > 0 {
4013            self.consume(len);
4014        }
4015        Ok(len)
4016    }
4017}
4018
4019impl<'a> ReversedMultiBufferBytes<'a> {
4020    fn consume(&mut self, len: usize) {
4021        self.range.end -= len;
4022        self.chunk = &self.chunk[..self.chunk.len() - len];
4023
4024        if !self.range.is_empty() && self.chunk.is_empty() {
4025            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
4026                self.chunk = chunk;
4027            } else {
4028                self.excerpts.next(&());
4029                if let Some(excerpt) = self.excerpts.item() {
4030                    let mut excerpt_bytes =
4031                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
4032                    self.chunk = excerpt_bytes.next().unwrap();
4033                    self.excerpt_bytes = Some(excerpt_bytes);
4034                }
4035            }
4036        }
4037    }
4038}
4039
4040impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
4041    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4042        let len = cmp::min(buf.len(), self.chunk.len());
4043        buf[..len].copy_from_slice(&self.chunk[..len]);
4044        buf[..len].reverse();
4045        if len > 0 {
4046            self.consume(len);
4047        }
4048        Ok(len)
4049    }
4050}
4051impl<'a> Iterator for ExcerptBytes<'a> {
4052    type Item = &'a [u8];
4053
4054    fn next(&mut self) -> Option<Self::Item> {
4055        if let Some(chunk) = self.content_bytes.next() {
4056            if !chunk.is_empty() {
4057                return Some(chunk);
4058            }
4059        }
4060
4061        if self.footer_height > 0 {
4062            let result = &NEWLINES[..self.footer_height];
4063            self.footer_height = 0;
4064            return Some(result);
4065        }
4066
4067        None
4068    }
4069}
4070
4071impl<'a> Iterator for ExcerptChunks<'a> {
4072    type Item = Chunk<'a>;
4073
4074    fn next(&mut self) -> Option<Self::Item> {
4075        if let Some(chunk) = self.content_chunks.next() {
4076            return Some(chunk);
4077        }
4078
4079        if self.footer_height > 0 {
4080            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
4081            self.footer_height = 0;
4082            return Some(Chunk {
4083                text,
4084                ..Default::default()
4085            });
4086        }
4087
4088        None
4089    }
4090}
4091
4092impl ToOffset for Point {
4093    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4094        snapshot.point_to_offset(*self)
4095    }
4096}
4097
4098impl ToOffset for usize {
4099    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4100        assert!(*self <= snapshot.len(), "offset is out of range");
4101        *self
4102    }
4103}
4104
4105impl ToOffset for OffsetUtf16 {
4106    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4107        snapshot.offset_utf16_to_offset(*self)
4108    }
4109}
4110
4111impl ToOffset for PointUtf16 {
4112    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4113        snapshot.point_utf16_to_offset(*self)
4114    }
4115}
4116
4117impl ToOffsetUtf16 for OffsetUtf16 {
4118    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4119        *self
4120    }
4121}
4122
4123impl ToOffsetUtf16 for usize {
4124    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4125        snapshot.offset_to_offset_utf16(*self)
4126    }
4127}
4128
4129impl ToPoint for usize {
4130    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
4131        snapshot.offset_to_point(*self)
4132    }
4133}
4134
4135impl ToPoint for Point {
4136    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
4137        *self
4138    }
4139}
4140
4141impl ToPointUtf16 for usize {
4142    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4143        snapshot.offset_to_point_utf16(*self)
4144    }
4145}
4146
4147impl ToPointUtf16 for Point {
4148    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4149        snapshot.point_to_point_utf16(*self)
4150    }
4151}
4152
4153impl ToPointUtf16 for PointUtf16 {
4154    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
4155        *self
4156    }
4157}
4158
4159fn build_excerpt_ranges<T>(
4160    buffer: &BufferSnapshot,
4161    ranges: &[Range<T>],
4162    context_line_count: u32,
4163) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
4164where
4165    T: text::ToPoint,
4166{
4167    let max_point = buffer.max_point();
4168    let mut range_counts = Vec::new();
4169    let mut excerpt_ranges = Vec::new();
4170    let mut range_iter = ranges
4171        .iter()
4172        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
4173        .peekable();
4174    while let Some(range) = range_iter.next() {
4175        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
4176        let mut excerpt_end = Point::new(range.end.row + 1 + context_line_count, 0).min(max_point);
4177        let mut ranges_in_excerpt = 1;
4178
4179        while let Some(next_range) = range_iter.peek() {
4180            if next_range.start.row <= excerpt_end.row + context_line_count {
4181                excerpt_end =
4182                    Point::new(next_range.end.row + 1 + context_line_count, 0).min(max_point);
4183                ranges_in_excerpt += 1;
4184                range_iter.next();
4185            } else {
4186                break;
4187            }
4188        }
4189
4190        excerpt_ranges.push(ExcerptRange {
4191            context: excerpt_start..excerpt_end,
4192            primary: Some(range),
4193        });
4194        range_counts.push(ranges_in_excerpt);
4195    }
4196
4197    (excerpt_ranges, range_counts)
4198}
4199
4200#[cfg(test)]
4201mod tests {
4202    use super::*;
4203    use futures::StreamExt;
4204    use gpui::{AppContext, Context, TestAppContext};
4205    use language::{Buffer, Rope};
4206    use parking_lot::RwLock;
4207    use rand::prelude::*;
4208    use settings::SettingsStore;
4209    use std::env;
4210    use util::test::sample_text;
4211
4212    #[gpui::test]
4213    fn test_singleton(cx: &mut AppContext) {
4214        let buffer = cx.new_model(|cx| {
4215            Buffer::new(
4216                0,
4217                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4218                sample_text(6, 6, 'a'),
4219            )
4220        });
4221        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4222
4223        let snapshot = multibuffer.read(cx).snapshot(cx);
4224        assert_eq!(snapshot.text(), buffer.read(cx).text());
4225
4226        assert_eq!(
4227            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4228            (0..buffer.read(cx).row_count())
4229                .map(Some)
4230                .collect::<Vec<_>>()
4231        );
4232
4233        buffer.update(cx, |buffer, cx| buffer.edit([(1..3, "XXX\n")], None, cx));
4234        let snapshot = multibuffer.read(cx).snapshot(cx);
4235
4236        assert_eq!(snapshot.text(), buffer.read(cx).text());
4237        assert_eq!(
4238            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4239            (0..buffer.read(cx).row_count())
4240                .map(Some)
4241                .collect::<Vec<_>>()
4242        );
4243    }
4244
4245    #[gpui::test]
4246    fn test_remote(cx: &mut AppContext) {
4247        let host_buffer =
4248            cx.new_model(|cx| Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "a"));
4249        let guest_buffer = cx.new_model(|cx| {
4250            let state = host_buffer.read(cx).to_proto();
4251            let ops = cx
4252                .background_executor()
4253                .block(host_buffer.read(cx).serialize_ops(None, cx));
4254            let mut buffer = Buffer::from_proto(1, Capability::ReadWrite, state, None).unwrap();
4255            buffer
4256                .apply_ops(
4257                    ops.into_iter()
4258                        .map(|op| language::proto::deserialize_operation(op).unwrap()),
4259                    cx,
4260                )
4261                .unwrap();
4262            buffer
4263        });
4264        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
4265        let snapshot = multibuffer.read(cx).snapshot(cx);
4266        assert_eq!(snapshot.text(), "a");
4267
4268        guest_buffer.update(cx, |buffer, cx| buffer.edit([(1..1, "b")], None, cx));
4269        let snapshot = multibuffer.read(cx).snapshot(cx);
4270        assert_eq!(snapshot.text(), "ab");
4271
4272        guest_buffer.update(cx, |buffer, cx| buffer.edit([(2..2, "c")], None, cx));
4273        let snapshot = multibuffer.read(cx).snapshot(cx);
4274        assert_eq!(snapshot.text(), "abc");
4275    }
4276
4277    #[gpui::test]
4278    fn test_excerpt_boundaries_and_clipping(cx: &mut AppContext) {
4279        let buffer_1 = cx.new_model(|cx| {
4280            Buffer::new(
4281                0,
4282                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4283                sample_text(6, 6, 'a'),
4284            )
4285        });
4286        let buffer_2 = cx.new_model(|cx| {
4287            Buffer::new(
4288                0,
4289                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4290                sample_text(6, 6, 'g'),
4291            )
4292        });
4293        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4294
4295        let events = Arc::new(RwLock::new(Vec::<Event>::new()));
4296        multibuffer.update(cx, |_, cx| {
4297            let events = events.clone();
4298            cx.subscribe(&multibuffer, move |_, _, event, _| {
4299                if let Event::Edited { .. } = event {
4300                    events.write().push(event.clone())
4301                }
4302            })
4303            .detach();
4304        });
4305
4306        let subscription = multibuffer.update(cx, |multibuffer, cx| {
4307            let subscription = multibuffer.subscribe();
4308            multibuffer.push_excerpts(
4309                buffer_1.clone(),
4310                [ExcerptRange {
4311                    context: Point::new(1, 2)..Point::new(2, 5),
4312                    primary: None,
4313                }],
4314                cx,
4315            );
4316            assert_eq!(
4317                subscription.consume().into_inner(),
4318                [Edit {
4319                    old: 0..0,
4320                    new: 0..10
4321                }]
4322            );
4323
4324            multibuffer.push_excerpts(
4325                buffer_1.clone(),
4326                [ExcerptRange {
4327                    context: Point::new(3, 3)..Point::new(4, 4),
4328                    primary: None,
4329                }],
4330                cx,
4331            );
4332            multibuffer.push_excerpts(
4333                buffer_2.clone(),
4334                [ExcerptRange {
4335                    context: Point::new(3, 1)..Point::new(3, 3),
4336                    primary: None,
4337                }],
4338                cx,
4339            );
4340            assert_eq!(
4341                subscription.consume().into_inner(),
4342                [Edit {
4343                    old: 10..10,
4344                    new: 10..22
4345                }]
4346            );
4347
4348            subscription
4349        });
4350
4351        // Adding excerpts emits an edited event.
4352        assert_eq!(
4353            events.read().as_slice(),
4354            &[
4355                Event::Edited {
4356                    singleton_buffer_edited: false
4357                },
4358                Event::Edited {
4359                    singleton_buffer_edited: false
4360                },
4361                Event::Edited {
4362                    singleton_buffer_edited: false
4363                }
4364            ]
4365        );
4366
4367        let snapshot = multibuffer.read(cx).snapshot(cx);
4368        assert_eq!(
4369            snapshot.text(),
4370            concat!(
4371                "bbbb\n",  // Preserve newlines
4372                "ccccc\n", //
4373                "ddd\n",   //
4374                "eeee\n",  //
4375                "jj"       //
4376            )
4377        );
4378        assert_eq!(
4379            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4380            [Some(1), Some(2), Some(3), Some(4), Some(3)]
4381        );
4382        assert_eq!(
4383            snapshot.buffer_rows(2).collect::<Vec<_>>(),
4384            [Some(3), Some(4), Some(3)]
4385        );
4386        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
4387        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
4388
4389        assert_eq!(
4390            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
4391            &[
4392                (0, "bbbb\nccccc".to_string(), true),
4393                (2, "ddd\neeee".to_string(), false),
4394                (4, "jj".to_string(), true),
4395            ]
4396        );
4397        assert_eq!(
4398            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
4399            &[(0, "bbbb\nccccc".to_string(), true)]
4400        );
4401        assert_eq!(
4402            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
4403            &[]
4404        );
4405        assert_eq!(
4406            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
4407            &[]
4408        );
4409        assert_eq!(
4410            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4411            &[(2, "ddd\neeee".to_string(), false)]
4412        );
4413        assert_eq!(
4414            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4415            &[(2, "ddd\neeee".to_string(), false)]
4416        );
4417        assert_eq!(
4418            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
4419            &[(2, "ddd\neeee".to_string(), false)]
4420        );
4421        assert_eq!(
4422            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
4423            &[(4, "jj".to_string(), true)]
4424        );
4425        assert_eq!(
4426            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
4427            &[]
4428        );
4429
4430        buffer_1.update(cx, |buffer, cx| {
4431            let text = "\n";
4432            buffer.edit(
4433                [
4434                    (Point::new(0, 0)..Point::new(0, 0), text),
4435                    (Point::new(2, 1)..Point::new(2, 3), text),
4436                ],
4437                None,
4438                cx,
4439            );
4440        });
4441
4442        let snapshot = multibuffer.read(cx).snapshot(cx);
4443        assert_eq!(
4444            snapshot.text(),
4445            concat!(
4446                "bbbb\n", // Preserve newlines
4447                "c\n",    //
4448                "cc\n",   //
4449                "ddd\n",  //
4450                "eeee\n", //
4451                "jj"      //
4452            )
4453        );
4454
4455        assert_eq!(
4456            subscription.consume().into_inner(),
4457            [Edit {
4458                old: 6..8,
4459                new: 6..7
4460            }]
4461        );
4462
4463        let snapshot = multibuffer.read(cx).snapshot(cx);
4464        assert_eq!(
4465            snapshot.clip_point(Point::new(0, 5), Bias::Left),
4466            Point::new(0, 4)
4467        );
4468        assert_eq!(
4469            snapshot.clip_point(Point::new(0, 5), Bias::Right),
4470            Point::new(0, 4)
4471        );
4472        assert_eq!(
4473            snapshot.clip_point(Point::new(5, 1), Bias::Right),
4474            Point::new(5, 1)
4475        );
4476        assert_eq!(
4477            snapshot.clip_point(Point::new(5, 2), Bias::Right),
4478            Point::new(5, 2)
4479        );
4480        assert_eq!(
4481            snapshot.clip_point(Point::new(5, 3), Bias::Right),
4482            Point::new(5, 2)
4483        );
4484
4485        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
4486            let (buffer_2_excerpt_id, _) =
4487                multibuffer.excerpts_for_buffer(&buffer_2, cx)[0].clone();
4488            multibuffer.remove_excerpts([buffer_2_excerpt_id], cx);
4489            multibuffer.snapshot(cx)
4490        });
4491
4492        assert_eq!(
4493            snapshot.text(),
4494            concat!(
4495                "bbbb\n", // Preserve newlines
4496                "c\n",    //
4497                "cc\n",   //
4498                "ddd\n",  //
4499                "eeee",   //
4500            )
4501        );
4502
4503        fn boundaries_in_range(
4504            range: Range<Point>,
4505            snapshot: &MultiBufferSnapshot,
4506        ) -> Vec<(u32, String, bool)> {
4507            snapshot
4508                .excerpt_boundaries_in_range(range)
4509                .map(|boundary| {
4510                    (
4511                        boundary.row,
4512                        boundary
4513                            .buffer
4514                            .text_for_range(boundary.range.context)
4515                            .collect::<String>(),
4516                        boundary.starts_new_buffer,
4517                    )
4518                })
4519                .collect::<Vec<_>>()
4520        }
4521    }
4522
4523    #[gpui::test]
4524    fn test_excerpt_events(cx: &mut AppContext) {
4525        let buffer_1 = cx.new_model(|cx| {
4526            Buffer::new(
4527                0,
4528                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4529                sample_text(10, 3, 'a'),
4530            )
4531        });
4532        let buffer_2 = cx.new_model(|cx| {
4533            Buffer::new(
4534                0,
4535                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4536                sample_text(10, 3, 'm'),
4537            )
4538        });
4539
4540        let leader_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4541        let follower_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4542        let follower_edit_event_count = Arc::new(RwLock::new(0));
4543
4544        follower_multibuffer.update(cx, |_, cx| {
4545            let follower_edit_event_count = follower_edit_event_count.clone();
4546            cx.subscribe(
4547                &leader_multibuffer,
4548                move |follower, _, event, cx| match event.clone() {
4549                    Event::ExcerptsAdded {
4550                        buffer,
4551                        predecessor,
4552                        excerpts,
4553                    } => follower.insert_excerpts_with_ids_after(predecessor, buffer, excerpts, cx),
4554                    Event::ExcerptsRemoved { ids } => follower.remove_excerpts(ids, cx),
4555                    Event::Edited { .. } => {
4556                        *follower_edit_event_count.write() += 1;
4557                    }
4558                    _ => {}
4559                },
4560            )
4561            .detach();
4562        });
4563
4564        leader_multibuffer.update(cx, |leader, cx| {
4565            leader.push_excerpts(
4566                buffer_1.clone(),
4567                [
4568                    ExcerptRange {
4569                        context: 0..8,
4570                        primary: None,
4571                    },
4572                    ExcerptRange {
4573                        context: 12..16,
4574                        primary: None,
4575                    },
4576                ],
4577                cx,
4578            );
4579            leader.insert_excerpts_after(
4580                leader.excerpt_ids()[0],
4581                buffer_2.clone(),
4582                [
4583                    ExcerptRange {
4584                        context: 0..5,
4585                        primary: None,
4586                    },
4587                    ExcerptRange {
4588                        context: 10..15,
4589                        primary: None,
4590                    },
4591                ],
4592                cx,
4593            )
4594        });
4595        assert_eq!(
4596            leader_multibuffer.read(cx).snapshot(cx).text(),
4597            follower_multibuffer.read(cx).snapshot(cx).text(),
4598        );
4599        assert_eq!(*follower_edit_event_count.read(), 2);
4600
4601        leader_multibuffer.update(cx, |leader, cx| {
4602            let excerpt_ids = leader.excerpt_ids();
4603            leader.remove_excerpts([excerpt_ids[1], excerpt_ids[3]], cx);
4604        });
4605        assert_eq!(
4606            leader_multibuffer.read(cx).snapshot(cx).text(),
4607            follower_multibuffer.read(cx).snapshot(cx).text(),
4608        );
4609        assert_eq!(*follower_edit_event_count.read(), 3);
4610
4611        // Removing an empty set of excerpts is a noop.
4612        leader_multibuffer.update(cx, |leader, cx| {
4613            leader.remove_excerpts([], cx);
4614        });
4615        assert_eq!(
4616            leader_multibuffer.read(cx).snapshot(cx).text(),
4617            follower_multibuffer.read(cx).snapshot(cx).text(),
4618        );
4619        assert_eq!(*follower_edit_event_count.read(), 3);
4620
4621        // Adding an empty set of excerpts is a noop.
4622        leader_multibuffer.update(cx, |leader, cx| {
4623            leader.push_excerpts::<usize>(buffer_2.clone(), [], cx);
4624        });
4625        assert_eq!(
4626            leader_multibuffer.read(cx).snapshot(cx).text(),
4627            follower_multibuffer.read(cx).snapshot(cx).text(),
4628        );
4629        assert_eq!(*follower_edit_event_count.read(), 3);
4630
4631        leader_multibuffer.update(cx, |leader, cx| {
4632            leader.clear(cx);
4633        });
4634        assert_eq!(
4635            leader_multibuffer.read(cx).snapshot(cx).text(),
4636            follower_multibuffer.read(cx).snapshot(cx).text(),
4637        );
4638        assert_eq!(*follower_edit_event_count.read(), 4);
4639    }
4640
4641    #[gpui::test]
4642    fn test_push_excerpts_with_context_lines(cx: &mut AppContext) {
4643        let buffer = cx.new_model(|cx| {
4644            Buffer::new(
4645                0,
4646                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4647                sample_text(20, 3, 'a'),
4648            )
4649        });
4650        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4651        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
4652            multibuffer.push_excerpts_with_context_lines(
4653                buffer.clone(),
4654                vec![
4655                    Point::new(3, 2)..Point::new(4, 2),
4656                    Point::new(7, 1)..Point::new(7, 3),
4657                    Point::new(15, 0)..Point::new(15, 0),
4658                ],
4659                2,
4660                cx,
4661            )
4662        });
4663
4664        let snapshot = multibuffer.read(cx).snapshot(cx);
4665        assert_eq!(
4666            snapshot.text(),
4667            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
4668        );
4669
4670        assert_eq!(
4671            anchor_ranges
4672                .iter()
4673                .map(|range| range.to_point(&snapshot))
4674                .collect::<Vec<_>>(),
4675            vec![
4676                Point::new(2, 2)..Point::new(3, 2),
4677                Point::new(6, 1)..Point::new(6, 3),
4678                Point::new(12, 0)..Point::new(12, 0)
4679            ]
4680        );
4681    }
4682
4683    #[gpui::test]
4684    async fn test_stream_excerpts_with_context_lines(cx: &mut TestAppContext) {
4685        let buffer = cx.new_model(|cx| {
4686            Buffer::new(
4687                0,
4688                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4689                sample_text(20, 3, 'a'),
4690            )
4691        });
4692        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4693        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
4694            let snapshot = buffer.read(cx);
4695            let ranges = vec![
4696                snapshot.anchor_before(Point::new(3, 2))..snapshot.anchor_before(Point::new(4, 2)),
4697                snapshot.anchor_before(Point::new(7, 1))..snapshot.anchor_before(Point::new(7, 3)),
4698                snapshot.anchor_before(Point::new(15, 0))
4699                    ..snapshot.anchor_before(Point::new(15, 0)),
4700            ];
4701            multibuffer.stream_excerpts_with_context_lines(buffer.clone(), ranges, 2, cx)
4702        });
4703
4704        let anchor_ranges = anchor_ranges.collect::<Vec<_>>().await;
4705
4706        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
4707        assert_eq!(
4708            snapshot.text(),
4709            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
4710        );
4711
4712        assert_eq!(
4713            anchor_ranges
4714                .iter()
4715                .map(|range| range.to_point(&snapshot))
4716                .collect::<Vec<_>>(),
4717            vec![
4718                Point::new(2, 2)..Point::new(3, 2),
4719                Point::new(6, 1)..Point::new(6, 3),
4720                Point::new(12, 0)..Point::new(12, 0)
4721            ]
4722        );
4723    }
4724
4725    #[gpui::test]
4726    fn test_empty_multibuffer(cx: &mut AppContext) {
4727        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4728
4729        let snapshot = multibuffer.read(cx).snapshot(cx);
4730        assert_eq!(snapshot.text(), "");
4731        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
4732        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
4733    }
4734
4735    #[gpui::test]
4736    fn test_singleton_multibuffer_anchors(cx: &mut AppContext) {
4737        let buffer = cx.new_model(|cx| {
4738            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4739        });
4740        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4741        let old_snapshot = multibuffer.read(cx).snapshot(cx);
4742        buffer.update(cx, |buffer, cx| {
4743            buffer.edit([(0..0, "X")], None, cx);
4744            buffer.edit([(5..5, "Y")], None, cx);
4745        });
4746        let new_snapshot = multibuffer.read(cx).snapshot(cx);
4747
4748        assert_eq!(old_snapshot.text(), "abcd");
4749        assert_eq!(new_snapshot.text(), "XabcdY");
4750
4751        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
4752        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
4753        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
4754        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
4755    }
4756
4757    #[gpui::test]
4758    fn test_multibuffer_anchors(cx: &mut AppContext) {
4759        let buffer_1 = cx.new_model(|cx| {
4760            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4761        });
4762        let buffer_2 = cx.new_model(|cx| {
4763            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "efghi")
4764        });
4765        let multibuffer = cx.new_model(|cx| {
4766            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
4767            multibuffer.push_excerpts(
4768                buffer_1.clone(),
4769                [ExcerptRange {
4770                    context: 0..4,
4771                    primary: None,
4772                }],
4773                cx,
4774            );
4775            multibuffer.push_excerpts(
4776                buffer_2.clone(),
4777                [ExcerptRange {
4778                    context: 0..5,
4779                    primary: None,
4780                }],
4781                cx,
4782            );
4783            multibuffer
4784        });
4785        let old_snapshot = multibuffer.read(cx).snapshot(cx);
4786
4787        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
4788        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
4789        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
4790        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
4791        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
4792        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
4793
4794        buffer_1.update(cx, |buffer, cx| {
4795            buffer.edit([(0..0, "W")], None, cx);
4796            buffer.edit([(5..5, "X")], None, cx);
4797        });
4798        buffer_2.update(cx, |buffer, cx| {
4799            buffer.edit([(0..0, "Y")], None, cx);
4800            buffer.edit([(6..6, "Z")], None, cx);
4801        });
4802        let new_snapshot = multibuffer.read(cx).snapshot(cx);
4803
4804        assert_eq!(old_snapshot.text(), "abcd\nefghi");
4805        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
4806
4807        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
4808        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
4809        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
4810        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
4811        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
4812        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
4813        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
4814        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
4815        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
4816        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
4817    }
4818
4819    #[gpui::test]
4820    fn test_resolving_anchors_after_replacing_their_excerpts(cx: &mut AppContext) {
4821        let buffer_1 = cx.new_model(|cx| {
4822            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4823        });
4824        let buffer_2 = cx.new_model(|cx| {
4825            Buffer::new(
4826                0,
4827                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4828                "ABCDEFGHIJKLMNOP",
4829            )
4830        });
4831        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4832
4833        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
4834        // Add an excerpt from buffer 1 that spans this new insertion.
4835        buffer_1.update(cx, |buffer, cx| buffer.edit([(4..4, "123")], None, cx));
4836        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
4837            multibuffer
4838                .push_excerpts(
4839                    buffer_1.clone(),
4840                    [ExcerptRange {
4841                        context: 0..7,
4842                        primary: None,
4843                    }],
4844                    cx,
4845                )
4846                .pop()
4847                .unwrap()
4848        });
4849
4850        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
4851        assert_eq!(snapshot_1.text(), "abcd123");
4852
4853        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
4854        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
4855            multibuffer.remove_excerpts([excerpt_id_1], cx);
4856            let mut ids = multibuffer
4857                .push_excerpts(
4858                    buffer_2.clone(),
4859                    [
4860                        ExcerptRange {
4861                            context: 0..4,
4862                            primary: None,
4863                        },
4864                        ExcerptRange {
4865                            context: 6..10,
4866                            primary: None,
4867                        },
4868                        ExcerptRange {
4869                            context: 12..16,
4870                            primary: None,
4871                        },
4872                    ],
4873                    cx,
4874                )
4875                .into_iter();
4876            (ids.next().unwrap(), ids.next().unwrap())
4877        });
4878        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
4879        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
4880
4881        // The old excerpt id doesn't get reused.
4882        assert_ne!(excerpt_id_2, excerpt_id_1);
4883
4884        // Resolve some anchors from the previous snapshot in the new snapshot.
4885        // The current excerpts are from a different buffer, so we don't attempt to
4886        // resolve the old text anchor in the new buffer.
4887        assert_eq!(
4888            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
4889            0
4890        );
4891        assert_eq!(
4892            snapshot_2.summaries_for_anchors::<usize, _>(&[
4893                snapshot_1.anchor_before(2),
4894                snapshot_1.anchor_after(3)
4895            ]),
4896            vec![0, 0]
4897        );
4898
4899        // Refresh anchors from the old snapshot. The return value indicates that both
4900        // anchors lost their original excerpt.
4901        let refresh =
4902            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
4903        assert_eq!(
4904            refresh,
4905            &[
4906                (0, snapshot_2.anchor_before(0), false),
4907                (1, snapshot_2.anchor_after(0), false),
4908            ]
4909        );
4910
4911        // Replace the middle excerpt with a smaller excerpt in buffer 2,
4912        // that intersects the old excerpt.
4913        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
4914            multibuffer.remove_excerpts([excerpt_id_3], cx);
4915            multibuffer
4916                .insert_excerpts_after(
4917                    excerpt_id_2,
4918                    buffer_2.clone(),
4919                    [ExcerptRange {
4920                        context: 5..8,
4921                        primary: None,
4922                    }],
4923                    cx,
4924                )
4925                .pop()
4926                .unwrap()
4927        });
4928
4929        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
4930        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
4931        assert_ne!(excerpt_id_5, excerpt_id_3);
4932
4933        // Resolve some anchors from the previous snapshot in the new snapshot.
4934        // The third anchor can't be resolved, since its excerpt has been removed,
4935        // so it resolves to the same position as its predecessor.
4936        let anchors = [
4937            snapshot_2.anchor_before(0),
4938            snapshot_2.anchor_after(2),
4939            snapshot_2.anchor_after(6),
4940            snapshot_2.anchor_after(14),
4941        ];
4942        assert_eq!(
4943            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
4944            &[0, 2, 9, 13]
4945        );
4946
4947        let new_anchors = snapshot_3.refresh_anchors(&anchors);
4948        assert_eq!(
4949            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
4950            &[(0, true), (1, true), (2, true), (3, true)]
4951        );
4952        assert_eq!(
4953            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
4954            &[0, 2, 7, 13]
4955        );
4956    }
4957
4958    #[gpui::test(iterations = 100)]
4959    fn test_random_multibuffer(cx: &mut AppContext, mut rng: StdRng) {
4960        let operations = env::var("OPERATIONS")
4961            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
4962            .unwrap_or(10);
4963
4964        let mut buffers: Vec<Model<Buffer>> = Vec::new();
4965        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4966        let mut excerpt_ids = Vec::<ExcerptId>::new();
4967        let mut expected_excerpts = Vec::<(Model<Buffer>, Range<text::Anchor>)>::new();
4968        let mut anchors = Vec::new();
4969        let mut old_versions = Vec::new();
4970
4971        for _ in 0..operations {
4972            match rng.gen_range(0..100) {
4973                0..=19 if !buffers.is_empty() => {
4974                    let buffer = buffers.choose(&mut rng).unwrap();
4975                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
4976                }
4977                20..=29 if !expected_excerpts.is_empty() => {
4978                    let mut ids_to_remove = vec![];
4979                    for _ in 0..rng.gen_range(1..=3) {
4980                        if expected_excerpts.is_empty() {
4981                            break;
4982                        }
4983
4984                        let ix = rng.gen_range(0..expected_excerpts.len());
4985                        ids_to_remove.push(excerpt_ids.remove(ix));
4986                        let (buffer, range) = expected_excerpts.remove(ix);
4987                        let buffer = buffer.read(cx);
4988                        log::info!(
4989                            "Removing excerpt {}: {:?}",
4990                            ix,
4991                            buffer
4992                                .text_for_range(range.to_offset(buffer))
4993                                .collect::<String>(),
4994                        );
4995                    }
4996                    let snapshot = multibuffer.read(cx).read(cx);
4997                    ids_to_remove.sort_unstable_by(|a, b| a.cmp(&b, &snapshot));
4998                    drop(snapshot);
4999                    multibuffer.update(cx, |multibuffer, cx| {
5000                        multibuffer.remove_excerpts(ids_to_remove, cx)
5001                    });
5002                }
5003                30..=39 if !expected_excerpts.is_empty() => {
5004                    let multibuffer = multibuffer.read(cx).read(cx);
5005                    let offset =
5006                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
5007                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
5008                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
5009                    anchors.push(multibuffer.anchor_at(offset, bias));
5010                    anchors.sort_by(|a, b| a.cmp(b, &multibuffer));
5011                }
5012                40..=44 if !anchors.is_empty() => {
5013                    let multibuffer = multibuffer.read(cx).read(cx);
5014                    let prev_len = anchors.len();
5015                    anchors = multibuffer
5016                        .refresh_anchors(&anchors)
5017                        .into_iter()
5018                        .map(|a| a.1)
5019                        .collect();
5020
5021                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
5022                    // overshoot its boundaries.
5023                    assert_eq!(anchors.len(), prev_len);
5024                    for anchor in &anchors {
5025                        if anchor.excerpt_id == ExcerptId::min()
5026                            || anchor.excerpt_id == ExcerptId::max()
5027                        {
5028                            continue;
5029                        }
5030
5031                        let excerpt = multibuffer.excerpt(anchor.excerpt_id).unwrap();
5032                        assert_eq!(excerpt.id, anchor.excerpt_id);
5033                        assert!(excerpt.contains(anchor));
5034                    }
5035                }
5036                _ => {
5037                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
5038                        let base_text = util::RandomCharIter::new(&mut rng)
5039                            .take(10)
5040                            .collect::<String>();
5041                        buffers.push(cx.new_model(|cx| {
5042                            Buffer::new(
5043                                0,
5044                                BufferId::new(cx.entity_id().as_u64()).unwrap(),
5045                                base_text,
5046                            )
5047                        }));
5048                        buffers.last().unwrap()
5049                    } else {
5050                        buffers.choose(&mut rng).unwrap()
5051                    };
5052
5053                    let buffer = buffer_handle.read(cx);
5054                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
5055                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5056                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
5057                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
5058                    let prev_excerpt_id = excerpt_ids
5059                        .get(prev_excerpt_ix)
5060                        .cloned()
5061                        .unwrap_or_else(ExcerptId::max);
5062                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
5063
5064                    log::info!(
5065                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
5066                        excerpt_ix,
5067                        expected_excerpts.len(),
5068                        buffer_handle.read(cx).remote_id(),
5069                        buffer.text(),
5070                        start_ix..end_ix,
5071                        &buffer.text()[start_ix..end_ix]
5072                    );
5073
5074                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
5075                        multibuffer
5076                            .insert_excerpts_after(
5077                                prev_excerpt_id,
5078                                buffer_handle.clone(),
5079                                [ExcerptRange {
5080                                    context: start_ix..end_ix,
5081                                    primary: None,
5082                                }],
5083                                cx,
5084                            )
5085                            .pop()
5086                            .unwrap()
5087                    });
5088
5089                    excerpt_ids.insert(excerpt_ix, excerpt_id);
5090                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
5091                }
5092            }
5093
5094            if rng.gen_bool(0.3) {
5095                multibuffer.update(cx, |multibuffer, cx| {
5096                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
5097                })
5098            }
5099
5100            let snapshot = multibuffer.read(cx).snapshot(cx);
5101
5102            let mut excerpt_starts = Vec::new();
5103            let mut expected_text = String::new();
5104            let mut expected_buffer_rows = Vec::new();
5105            for (buffer, range) in &expected_excerpts {
5106                let buffer = buffer.read(cx);
5107                let buffer_range = range.to_offset(buffer);
5108
5109                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
5110                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
5111                expected_text.push('\n');
5112
5113                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
5114                    ..=buffer.offset_to_point(buffer_range.end).row;
5115                for row in buffer_row_range {
5116                    expected_buffer_rows.push(Some(row));
5117                }
5118            }
5119            // Remove final trailing newline.
5120            if !expected_excerpts.is_empty() {
5121                expected_text.pop();
5122            }
5123
5124            // Always report one buffer row
5125            if expected_buffer_rows.is_empty() {
5126                expected_buffer_rows.push(Some(0));
5127            }
5128
5129            assert_eq!(snapshot.text(), expected_text);
5130            log::info!("MultiBuffer text: {:?}", expected_text);
5131
5132            assert_eq!(
5133                snapshot.buffer_rows(0).collect::<Vec<_>>(),
5134                expected_buffer_rows,
5135            );
5136
5137            for _ in 0..5 {
5138                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
5139                assert_eq!(
5140                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
5141                    &expected_buffer_rows[start_row..],
5142                    "buffer_rows({})",
5143                    start_row
5144                );
5145            }
5146
5147            assert_eq!(
5148                snapshot.max_buffer_row(),
5149                expected_buffer_rows.into_iter().flatten().max().unwrap()
5150            );
5151
5152            let mut excerpt_starts = excerpt_starts.into_iter();
5153            for (buffer, range) in &expected_excerpts {
5154                let buffer = buffer.read(cx);
5155                let buffer_id = buffer.remote_id();
5156                let buffer_range = range.to_offset(buffer);
5157                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
5158                let buffer_start_point_utf16 =
5159                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
5160
5161                let excerpt_start = excerpt_starts.next().unwrap();
5162                let mut offset = excerpt_start.len;
5163                let mut buffer_offset = buffer_range.start;
5164                let mut point = excerpt_start.lines;
5165                let mut buffer_point = buffer_start_point;
5166                let mut point_utf16 = excerpt_start.lines_utf16();
5167                let mut buffer_point_utf16 = buffer_start_point_utf16;
5168                for ch in buffer
5169                    .snapshot()
5170                    .chunks(buffer_range.clone(), false)
5171                    .flat_map(|c| c.text.chars())
5172                {
5173                    for _ in 0..ch.len_utf8() {
5174                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
5175                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
5176                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
5177                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
5178                        assert_eq!(
5179                            left_offset,
5180                            excerpt_start.len + (buffer_left_offset - buffer_range.start),
5181                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
5182                            offset,
5183                            buffer_id,
5184                            buffer_offset,
5185                        );
5186                        assert_eq!(
5187                            right_offset,
5188                            excerpt_start.len + (buffer_right_offset - buffer_range.start),
5189                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
5190                            offset,
5191                            buffer_id,
5192                            buffer_offset,
5193                        );
5194
5195                        let left_point = snapshot.clip_point(point, Bias::Left);
5196                        let right_point = snapshot.clip_point(point, Bias::Right);
5197                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
5198                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
5199                        assert_eq!(
5200                            left_point,
5201                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
5202                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
5203                            point,
5204                            buffer_id,
5205                            buffer_point,
5206                        );
5207                        assert_eq!(
5208                            right_point,
5209                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
5210                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
5211                            point,
5212                            buffer_id,
5213                            buffer_point,
5214                        );
5215
5216                        assert_eq!(
5217                            snapshot.point_to_offset(left_point),
5218                            left_offset,
5219                            "point_to_offset({:?})",
5220                            left_point,
5221                        );
5222                        assert_eq!(
5223                            snapshot.offset_to_point(left_offset),
5224                            left_point,
5225                            "offset_to_point({:?})",
5226                            left_offset,
5227                        );
5228
5229                        offset += 1;
5230                        buffer_offset += 1;
5231                        if ch == '\n' {
5232                            point += Point::new(1, 0);
5233                            buffer_point += Point::new(1, 0);
5234                        } else {
5235                            point += Point::new(0, 1);
5236                            buffer_point += Point::new(0, 1);
5237                        }
5238                    }
5239
5240                    for _ in 0..ch.len_utf16() {
5241                        let left_point_utf16 =
5242                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Left);
5243                        let right_point_utf16 =
5244                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Right);
5245                        let buffer_left_point_utf16 =
5246                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Left);
5247                        let buffer_right_point_utf16 =
5248                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Right);
5249                        assert_eq!(
5250                            left_point_utf16,
5251                            excerpt_start.lines_utf16()
5252                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
5253                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
5254                            point_utf16,
5255                            buffer_id,
5256                            buffer_point_utf16,
5257                        );
5258                        assert_eq!(
5259                            right_point_utf16,
5260                            excerpt_start.lines_utf16()
5261                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
5262                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
5263                            point_utf16,
5264                            buffer_id,
5265                            buffer_point_utf16,
5266                        );
5267
5268                        if ch == '\n' {
5269                            point_utf16 += PointUtf16::new(1, 0);
5270                            buffer_point_utf16 += PointUtf16::new(1, 0);
5271                        } else {
5272                            point_utf16 += PointUtf16::new(0, 1);
5273                            buffer_point_utf16 += PointUtf16::new(0, 1);
5274                        }
5275                    }
5276                }
5277            }
5278
5279            for (row, line) in expected_text.split('\n').enumerate() {
5280                assert_eq!(
5281                    snapshot.line_len(row as u32),
5282                    line.len() as u32,
5283                    "line_len({}).",
5284                    row
5285                );
5286            }
5287
5288            let text_rope = Rope::from(expected_text.as_str());
5289            for _ in 0..10 {
5290                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5291                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5292
5293                let text_for_range = snapshot
5294                    .text_for_range(start_ix..end_ix)
5295                    .collect::<String>();
5296                assert_eq!(
5297                    text_for_range,
5298                    &expected_text[start_ix..end_ix],
5299                    "incorrect text for range {:?}",
5300                    start_ix..end_ix
5301                );
5302
5303                let excerpted_buffer_ranges = multibuffer
5304                    .read(cx)
5305                    .range_to_buffer_ranges(start_ix..end_ix, cx);
5306                let excerpted_buffers_text = excerpted_buffer_ranges
5307                    .iter()
5308                    .map(|(buffer, buffer_range, _)| {
5309                        buffer
5310                            .read(cx)
5311                            .text_for_range(buffer_range.clone())
5312                            .collect::<String>()
5313                    })
5314                    .collect::<Vec<_>>()
5315                    .join("\n");
5316                assert_eq!(excerpted_buffers_text, text_for_range);
5317                if !expected_excerpts.is_empty() {
5318                    assert!(!excerpted_buffer_ranges.is_empty());
5319                }
5320
5321                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
5322                assert_eq!(
5323                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
5324                    expected_summary,
5325                    "incorrect summary for range {:?}",
5326                    start_ix..end_ix
5327                );
5328            }
5329
5330            // Anchor resolution
5331            let summaries = snapshot.summaries_for_anchors::<usize, _>(&anchors);
5332            assert_eq!(anchors.len(), summaries.len());
5333            for (anchor, resolved_offset) in anchors.iter().zip(summaries) {
5334                assert!(resolved_offset <= snapshot.len());
5335                assert_eq!(
5336                    snapshot.summary_for_anchor::<usize>(anchor),
5337                    resolved_offset
5338                );
5339            }
5340
5341            for _ in 0..10 {
5342                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5343                assert_eq!(
5344                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
5345                    expected_text[..end_ix].chars().rev().collect::<String>(),
5346                );
5347            }
5348
5349            for _ in 0..10 {
5350                let end_ix = rng.gen_range(0..=text_rope.len());
5351                let start_ix = rng.gen_range(0..=end_ix);
5352                assert_eq!(
5353                    snapshot
5354                        .bytes_in_range(start_ix..end_ix)
5355                        .flatten()
5356                        .copied()
5357                        .collect::<Vec<_>>(),
5358                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
5359                    "bytes_in_range({:?})",
5360                    start_ix..end_ix,
5361                );
5362            }
5363        }
5364
5365        let snapshot = multibuffer.read(cx).snapshot(cx);
5366        for (old_snapshot, subscription) in old_versions {
5367            let edits = subscription.consume().into_inner();
5368
5369            log::info!(
5370                "applying subscription edits to old text: {:?}: {:?}",
5371                old_snapshot.text(),
5372                edits,
5373            );
5374
5375            let mut text = old_snapshot.text();
5376            for edit in edits {
5377                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
5378                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
5379            }
5380            assert_eq!(text.to_string(), snapshot.text());
5381        }
5382    }
5383
5384    #[gpui::test]
5385    fn test_history(cx: &mut AppContext) {
5386        let test_settings = SettingsStore::test(cx);
5387        cx.set_global(test_settings);
5388
5389        let buffer_1 = cx.new_model(|cx| {
5390            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "1234")
5391        });
5392        let buffer_2 = cx.new_model(|cx| {
5393            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "5678")
5394        });
5395        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5396        let group_interval = multibuffer.read(cx).history.group_interval;
5397        multibuffer.update(cx, |multibuffer, cx| {
5398            multibuffer.push_excerpts(
5399                buffer_1.clone(),
5400                [ExcerptRange {
5401                    context: 0..buffer_1.read(cx).len(),
5402                    primary: None,
5403                }],
5404                cx,
5405            );
5406            multibuffer.push_excerpts(
5407                buffer_2.clone(),
5408                [ExcerptRange {
5409                    context: 0..buffer_2.read(cx).len(),
5410                    primary: None,
5411                }],
5412                cx,
5413            );
5414        });
5415
5416        let mut now = Instant::now();
5417
5418        multibuffer.update(cx, |multibuffer, cx| {
5419            let transaction_1 = multibuffer.start_transaction_at(now, cx).unwrap();
5420            multibuffer.edit(
5421                [
5422                    (Point::new(0, 0)..Point::new(0, 0), "A"),
5423                    (Point::new(1, 0)..Point::new(1, 0), "A"),
5424                ],
5425                None,
5426                cx,
5427            );
5428            multibuffer.edit(
5429                [
5430                    (Point::new(0, 1)..Point::new(0, 1), "B"),
5431                    (Point::new(1, 1)..Point::new(1, 1), "B"),
5432                ],
5433                None,
5434                cx,
5435            );
5436            multibuffer.end_transaction_at(now, cx);
5437            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5438
5439            // Edit buffer 1 through the multibuffer
5440            now += 2 * group_interval;
5441            multibuffer.start_transaction_at(now, cx);
5442            multibuffer.edit([(2..2, "C")], None, cx);
5443            multibuffer.end_transaction_at(now, cx);
5444            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
5445
5446            // Edit buffer 1 independently
5447            buffer_1.update(cx, |buffer_1, cx| {
5448                buffer_1.start_transaction_at(now);
5449                buffer_1.edit([(3..3, "D")], None, cx);
5450                buffer_1.end_transaction_at(now, cx);
5451
5452                now += 2 * group_interval;
5453                buffer_1.start_transaction_at(now);
5454                buffer_1.edit([(4..4, "E")], None, cx);
5455                buffer_1.end_transaction_at(now, cx);
5456            });
5457            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
5458
5459            // An undo in the multibuffer undoes the multibuffer transaction
5460            // and also any individual buffer edits that have occurred since
5461            // that transaction.
5462            multibuffer.undo(cx);
5463            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5464
5465            multibuffer.undo(cx);
5466            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5467
5468            multibuffer.redo(cx);
5469            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5470
5471            multibuffer.redo(cx);
5472            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
5473
5474            // Undo buffer 2 independently.
5475            buffer_2.update(cx, |buffer_2, cx| buffer_2.undo(cx));
5476            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\n5678");
5477
5478            // An undo in the multibuffer undoes the components of the
5479            // the last multibuffer transaction that are not already undone.
5480            multibuffer.undo(cx);
5481            assert_eq!(multibuffer.read(cx).text(), "AB1234\n5678");
5482
5483            multibuffer.undo(cx);
5484            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5485
5486            multibuffer.redo(cx);
5487            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5488
5489            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
5490            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
5491
5492            // Redo stack gets cleared after an edit.
5493            now += 2 * group_interval;
5494            multibuffer.start_transaction_at(now, cx);
5495            multibuffer.edit([(0..0, "X")], None, cx);
5496            multibuffer.end_transaction_at(now, cx);
5497            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5498            multibuffer.redo(cx);
5499            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5500            multibuffer.undo(cx);
5501            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
5502            multibuffer.undo(cx);
5503            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5504
5505            // Transactions can be grouped manually.
5506            multibuffer.redo(cx);
5507            multibuffer.redo(cx);
5508            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5509            multibuffer.group_until_transaction(transaction_1, cx);
5510            multibuffer.undo(cx);
5511            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5512            multibuffer.redo(cx);
5513            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5514        });
5515    }
5516}