1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt, Offset};
   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, EntityId, EventEmitter, Model, ModelContext};
  10use itertools::Itertools;
  11use language::{
  12    char_kind,
  13    language_settings::{language_settings, LanguageSettings},
  14    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharKind, Chunk,
  15    CursorShape, DiagnosticEntry, File, IndentGuide, IndentSize, Language, LanguageScope,
  16    OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension,
  17    ToOffset as _, ToOffsetUtf16 as _, ToPoint as _, ToPointUtf16 as _, TransactionId, Unclipped,
  18};
  19use smallvec::SmallVec;
  20use std::{
  21    any::type_name,
  22    borrow::Cow,
  23    cell::{Ref, RefCell},
  24    cmp, fmt,
  25    future::Future,
  26    io,
  27    iter::{self, FromIterator},
  28    mem,
  29    ops::{Range, RangeBounds, Sub},
  30    str,
  31    sync::Arc,
  32    time::{Duration, Instant},
  33};
  34use sum_tree::{Bias, Cursor, SumTree};
  35use text::{
  36    locator::Locator,
  37    subscription::{Subscription, Topic},
  38    BufferId, Edit, TextSummary,
  39};
  40use theme::SyntaxTheme;
  41
  42use util::post_inc;
  43
  44#[cfg(any(test, feature = "test-support"))]
  45use gpui::Context;
  46
  47const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  48
  49#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  50pub struct ExcerptId(usize);
  51
  52impl From<ExcerptId> for EntityId {
  53    fn from(id: ExcerptId) -> Self {
  54        EntityId::from(id.0 as u64)
  55    }
  56}
  57
  58/// One or more [`Buffers`](Buffer) being edited in a single view.
  59///
  60/// See <https://zed.dev/features#multi-buffers>
  61pub struct MultiBuffer {
  62    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  63    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  64    snapshot: RefCell<MultiBufferSnapshot>,
  65    /// Contains the state of the buffers being edited
  66    buffers: RefCell<HashMap<BufferId, BufferState>>,
  67    subscriptions: Topic,
  68    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  69    singleton: bool,
  70    replica_id: ReplicaId,
  71    history: History,
  72    title: Option<String>,
  73    capability: Capability,
  74}
  75
  76#[derive(Clone, Debug, PartialEq, Eq)]
  77pub enum Event {
  78    ExcerptsAdded {
  79        buffer: Model<Buffer>,
  80        predecessor: ExcerptId,
  81        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  82    },
  83    ExcerptsRemoved {
  84        ids: Vec<ExcerptId>,
  85    },
  86    ExcerptsExpanded {
  87        ids: Vec<ExcerptId>,
  88    },
  89    ExcerptsEdited {
  90        ids: Vec<ExcerptId>,
  91    },
  92    Edited {
  93        singleton_buffer_edited: bool,
  94    },
  95    TransactionUndone {
  96        transaction_id: TransactionId,
  97    },
  98    Reloaded,
  99    DiffBaseChanged,
 100    DiffUpdated {
 101        buffer: Model<Buffer>,
 102    },
 103    LanguageChanged(BufferId),
 104    CapabilityChanged,
 105    Reparsed(BufferId),
 106    Saved,
 107    FileHandleChanged,
 108    Closed,
 109    DirtyChanged,
 110    DiagnosticsUpdated,
 111}
 112
 113pub type MultiBufferPoint = Point;
 114
 115#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, serde::Deserialize)]
 116#[serde(transparent)]
 117pub struct MultiBufferRow(pub u32);
 118
 119impl MultiBufferRow {
 120    pub const MIN: Self = Self(0);
 121    pub const MAX: Self = Self(u32::MAX);
 122}
 123
 124#[derive(Clone)]
 125struct History {
 126    next_transaction_id: TransactionId,
 127    undo_stack: Vec<Transaction>,
 128    redo_stack: Vec<Transaction>,
 129    transaction_depth: usize,
 130    group_interval: Duration,
 131}
 132
 133#[derive(Clone)]
 134struct Transaction {
 135    id: TransactionId,
 136    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 137    first_edit_at: Instant,
 138    last_edit_at: Instant,
 139    suppress_grouping: bool,
 140}
 141
 142pub trait ToOffset: 'static + fmt::Debug {
 143    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 144}
 145
 146pub trait ToOffsetUtf16: 'static + fmt::Debug {
 147    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 148}
 149
 150pub trait ToPoint: 'static + fmt::Debug {
 151    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 152}
 153
 154pub trait ToPointUtf16: 'static + fmt::Debug {
 155    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 156}
 157
 158struct BufferState {
 159    buffer: Model<Buffer>,
 160    last_version: clock::Global,
 161    last_non_text_state_update_count: usize,
 162    excerpts: Vec<Locator>,
 163    _subscriptions: [gpui::Subscription; 2],
 164}
 165
 166/// The contents of a [`MultiBuffer`] at a single point in time.
 167#[derive(Clone, Default)]
 168pub struct MultiBufferSnapshot {
 169    singleton: bool,
 170    excerpts: SumTree<Excerpt>,
 171    excerpt_ids: SumTree<ExcerptIdMapping>,
 172    trailing_excerpt_update_count: usize,
 173    non_text_state_update_count: usize,
 174    edit_count: usize,
 175    is_dirty: bool,
 176    has_conflict: bool,
 177    show_headers: bool,
 178}
 179
 180pub struct ExcerptInfo {
 181    pub id: ExcerptId,
 182    pub buffer: BufferSnapshot,
 183    pub buffer_id: BufferId,
 184    pub range: ExcerptRange<text::Anchor>,
 185}
 186
 187impl std::fmt::Debug for ExcerptInfo {
 188    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 189        f.debug_struct(type_name::<Self>())
 190            .field("id", &self.id)
 191            .field("buffer_id", &self.buffer_id)
 192            .field("range", &self.range)
 193            .finish()
 194    }
 195}
 196
 197/// A boundary between [`Excerpt`]s in a [`MultiBuffer`]
 198#[derive(Debug)]
 199pub struct ExcerptBoundary {
 200    pub prev: Option<ExcerptInfo>,
 201    pub next: Option<ExcerptInfo>,
 202    /// The row in the `MultiBuffer` where the boundary is located
 203    pub row: MultiBufferRow,
 204}
 205
 206impl ExcerptBoundary {
 207    pub fn starts_new_buffer(&self) -> bool {
 208        match (self.prev.as_ref(), self.next.as_ref()) {
 209            (None, _) => true,
 210            (Some(_), None) => false,
 211            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 212        }
 213    }
 214}
 215
 216/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 217#[derive(Clone)]
 218struct Excerpt {
 219    /// The unique identifier for this excerpt
 220    id: ExcerptId,
 221    /// The location of the excerpt in the [`MultiBuffer`]
 222    locator: Locator,
 223    /// The buffer being excerpted
 224    buffer_id: BufferId,
 225    /// A snapshot of the buffer being excerpted
 226    buffer: BufferSnapshot,
 227    /// The range of the buffer to be shown in the excerpt
 228    range: ExcerptRange<text::Anchor>,
 229    /// The last row in the excerpted slice of the buffer
 230    max_buffer_row: BufferRow,
 231    /// A summary of the text in the excerpt
 232    text_summary: TextSummary,
 233    has_trailing_newline: bool,
 234}
 235
 236/// A public view into an [`Excerpt`] in a [`MultiBuffer`].
 237///
 238/// Contains methods for getting the [`Buffer`] of the excerpt,
 239/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 240#[derive(Clone)]
 241pub struct MultiBufferExcerpt<'a> {
 242    excerpt: &'a Excerpt,
 243    excerpt_offset: usize,
 244}
 245
 246#[derive(Clone, Debug)]
 247struct ExcerptIdMapping {
 248    id: ExcerptId,
 249    locator: Locator,
 250}
 251
 252/// A range of text from a single [`Buffer`], to be shown as an [`Excerpt`].
 253/// These ranges are relative to the buffer itself
 254#[derive(Clone, Debug, Eq, PartialEq)]
 255pub struct ExcerptRange<T> {
 256    /// The full range of text to be shown in the excerpt.
 257    pub context: Range<T>,
 258    /// The primary range of text to be highlighted in the excerpt.
 259    /// In a multi-buffer search, this would be the text that matched the search
 260    pub primary: Option<Range<T>>,
 261}
 262
 263#[derive(Clone, Debug, Default)]
 264pub struct ExcerptSummary {
 265    excerpt_id: ExcerptId,
 266    /// The location of the last [`Excerpt`] being summarized
 267    excerpt_locator: Locator,
 268    /// The maximum row of the [`Excerpt`]s being summarized
 269    max_buffer_row: MultiBufferRow,
 270    text: TextSummary,
 271}
 272
 273#[derive(Clone)]
 274pub struct MultiBufferRows<'a> {
 275    buffer_row_range: Range<u32>,
 276    excerpts: Cursor<'a, Excerpt, Point>,
 277}
 278
 279pub struct MultiBufferChunks<'a> {
 280    range: Range<usize>,
 281    excerpts: Cursor<'a, Excerpt, usize>,
 282    excerpt_chunks: Option<ExcerptChunks<'a>>,
 283    language_aware: bool,
 284}
 285
 286pub struct MultiBufferBytes<'a> {
 287    range: Range<usize>,
 288    excerpts: Cursor<'a, Excerpt, usize>,
 289    excerpt_bytes: Option<ExcerptBytes<'a>>,
 290    chunk: &'a [u8],
 291}
 292
 293pub struct ReversedMultiBufferBytes<'a> {
 294    range: Range<usize>,
 295    excerpts: Cursor<'a, Excerpt, usize>,
 296    excerpt_bytes: Option<ExcerptBytes<'a>>,
 297    chunk: &'a [u8],
 298}
 299
 300struct ExcerptChunks<'a> {
 301    excerpt_id: ExcerptId,
 302    content_chunks: BufferChunks<'a>,
 303    footer_height: usize,
 304}
 305
 306struct ExcerptBytes<'a> {
 307    content_bytes: text::Bytes<'a>,
 308    padding_height: usize,
 309    reversed: bool,
 310}
 311
 312#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 313pub enum ExpandExcerptDirection {
 314    Up,
 315    Down,
 316    UpAndDown,
 317}
 318
 319impl ExpandExcerptDirection {
 320    pub fn should_expand_up(&self) -> bool {
 321        match self {
 322            ExpandExcerptDirection::Up => true,
 323            ExpandExcerptDirection::Down => false,
 324            ExpandExcerptDirection::UpAndDown => true,
 325        }
 326    }
 327
 328    pub fn should_expand_down(&self) -> bool {
 329        match self {
 330            ExpandExcerptDirection::Up => false,
 331            ExpandExcerptDirection::Down => true,
 332            ExpandExcerptDirection::UpAndDown => true,
 333        }
 334    }
 335}
 336
 337#[derive(Clone, Debug, PartialEq)]
 338pub struct MultiBufferIndentGuide {
 339    pub multibuffer_row_range: Range<MultiBufferRow>,
 340    pub buffer: IndentGuide,
 341}
 342
 343impl std::ops::Deref for MultiBufferIndentGuide {
 344    type Target = IndentGuide;
 345
 346    fn deref(&self) -> &Self::Target {
 347        &self.buffer
 348    }
 349}
 350
 351impl MultiBuffer {
 352    pub fn new(replica_id: ReplicaId, capability: Capability) -> Self {
 353        Self {
 354            snapshot: RefCell::new(MultiBufferSnapshot {
 355                show_headers: true,
 356                ..MultiBufferSnapshot::default()
 357            }),
 358            buffers: RefCell::default(),
 359            subscriptions: Topic::default(),
 360            singleton: false,
 361            capability,
 362            replica_id,
 363            title: None,
 364            history: History {
 365                next_transaction_id: clock::Lamport::default(),
 366                undo_stack: Vec::new(),
 367                redo_stack: Vec::new(),
 368                transaction_depth: 0,
 369                group_interval: Duration::from_millis(300),
 370            },
 371        }
 372    }
 373
 374    pub fn without_headers(replica_id: ReplicaId, capability: Capability) -> Self {
 375        Self {
 376            snapshot: Default::default(),
 377            buffers: Default::default(),
 378            subscriptions: Default::default(),
 379            singleton: false,
 380            capability,
 381            replica_id,
 382            history: History {
 383                next_transaction_id: Default::default(),
 384                undo_stack: Default::default(),
 385                redo_stack: Default::default(),
 386                transaction_depth: 0,
 387                group_interval: Duration::from_millis(300),
 388            },
 389            title: Default::default(),
 390        }
 391    }
 392
 393    pub fn clone(&self, new_cx: &mut ModelContext<Self>) -> Self {
 394        let mut buffers = HashMap::default();
 395        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 396            buffers.insert(
 397                *buffer_id,
 398                BufferState {
 399                    buffer: buffer_state.buffer.clone(),
 400                    last_version: buffer_state.last_version.clone(),
 401                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 402                    excerpts: buffer_state.excerpts.clone(),
 403                    _subscriptions: [
 404                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 405                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 406                    ],
 407                },
 408            );
 409        }
 410        Self {
 411            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 412            buffers: RefCell::new(buffers),
 413            subscriptions: Default::default(),
 414            singleton: self.singleton,
 415            capability: self.capability,
 416            replica_id: self.replica_id,
 417            history: self.history.clone(),
 418            title: self.title.clone(),
 419        }
 420    }
 421
 422    pub fn with_title(mut self, title: String) -> Self {
 423        self.title = Some(title);
 424        self
 425    }
 426
 427    pub fn read_only(&self) -> bool {
 428        self.capability == Capability::ReadOnly
 429    }
 430
 431    pub fn singleton(buffer: Model<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 432        let mut this = Self::new(buffer.read(cx).replica_id(), buffer.read(cx).capability());
 433        this.singleton = true;
 434        this.push_excerpts(
 435            buffer,
 436            [ExcerptRange {
 437                context: text::Anchor::MIN..text::Anchor::MAX,
 438                primary: None,
 439            }],
 440            cx,
 441        );
 442        this.snapshot.borrow_mut().singleton = true;
 443        this
 444    }
 445
 446    pub fn replica_id(&self) -> ReplicaId {
 447        self.replica_id
 448    }
 449
 450    /// Returns an up-to-date snapshot of the MultiBuffer.
 451    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 452        self.sync(cx);
 453        self.snapshot.borrow().clone()
 454    }
 455
 456    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 457        self.sync(cx);
 458        self.snapshot.borrow()
 459    }
 460
 461    pub fn as_singleton(&self) -> Option<Model<Buffer>> {
 462        if self.singleton {
 463            return Some(
 464                self.buffers
 465                    .borrow()
 466                    .values()
 467                    .next()
 468                    .unwrap()
 469                    .buffer
 470                    .clone(),
 471            );
 472        } else {
 473            None
 474        }
 475    }
 476
 477    pub fn is_singleton(&self) -> bool {
 478        self.singleton
 479    }
 480
 481    pub fn subscribe(&mut self) -> Subscription {
 482        self.subscriptions.subscribe()
 483    }
 484
 485    pub fn is_dirty(&self, cx: &AppContext) -> bool {
 486        self.read(cx).is_dirty()
 487    }
 488
 489    pub fn has_conflict(&self, cx: &AppContext) -> bool {
 490        self.read(cx).has_conflict()
 491    }
 492
 493    // The `is_empty` signature doesn't match what clippy expects
 494    #[allow(clippy::len_without_is_empty)]
 495    pub fn len(&self, cx: &AppContext) -> usize {
 496        self.read(cx).len()
 497    }
 498
 499    pub fn is_empty(&self, cx: &AppContext) -> bool {
 500        self.len(cx) != 0
 501    }
 502
 503    pub fn symbols_containing<T: ToOffset>(
 504        &self,
 505        offset: T,
 506        theme: Option<&SyntaxTheme>,
 507        cx: &AppContext,
 508    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 509        self.read(cx).symbols_containing(offset, theme)
 510    }
 511
 512    pub fn edit<I, S, T>(
 513        &mut self,
 514        edits: I,
 515        mut autoindent_mode: Option<AutoindentMode>,
 516        cx: &mut ModelContext<Self>,
 517    ) where
 518        I: IntoIterator<Item = (Range<S>, T)>,
 519        S: ToOffset,
 520        T: Into<Arc<str>>,
 521    {
 522        if self.read_only() {
 523            return;
 524        }
 525        if self.buffers.borrow().is_empty() {
 526            return;
 527        }
 528
 529        let snapshot = self.read(cx);
 530        let edits = edits.into_iter().map(|(range, new_text)| {
 531            let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 532            if range.start > range.end {
 533                mem::swap(&mut range.start, &mut range.end);
 534            }
 535            (range, new_text)
 536        });
 537
 538        if let Some(buffer) = self.as_singleton() {
 539            buffer.update(cx, |buffer, cx| {
 540                buffer.edit(edits, autoindent_mode, cx);
 541            });
 542            cx.emit(Event::ExcerptsEdited {
 543                ids: self.excerpt_ids(),
 544            });
 545            return;
 546        }
 547
 548        let original_indent_columns = match &mut autoindent_mode {
 549            Some(AutoindentMode::Block {
 550                original_indent_columns,
 551            }) => mem::take(original_indent_columns),
 552            _ => Default::default(),
 553        };
 554
 555        struct BufferEdit {
 556            range: Range<usize>,
 557            new_text: Arc<str>,
 558            is_insertion: bool,
 559            original_indent_column: u32,
 560        }
 561        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 562        let mut edited_excerpt_ids = Vec::new();
 563        let mut cursor = snapshot.excerpts.cursor::<usize>();
 564        for (ix, (range, new_text)) in edits.enumerate() {
 565            let new_text: Arc<str> = new_text.into();
 566            let original_indent_column = original_indent_columns.get(ix).copied().unwrap_or(0);
 567            cursor.seek(&range.start, Bias::Right, &());
 568            if cursor.item().is_none() && range.start == *cursor.start() {
 569                cursor.prev(&());
 570            }
 571            let start_excerpt = cursor.item().expect("start offset out of bounds");
 572            let start_overshoot = range.start - cursor.start();
 573            let buffer_start = start_excerpt
 574                .range
 575                .context
 576                .start
 577                .to_offset(&start_excerpt.buffer)
 578                + start_overshoot;
 579            edited_excerpt_ids.push(start_excerpt.id);
 580
 581            cursor.seek(&range.end, Bias::Right, &());
 582            if cursor.item().is_none() && range.end == *cursor.start() {
 583                cursor.prev(&());
 584            }
 585            let end_excerpt = cursor.item().expect("end offset out of bounds");
 586            let end_overshoot = range.end - cursor.start();
 587            let buffer_end = end_excerpt
 588                .range
 589                .context
 590                .start
 591                .to_offset(&end_excerpt.buffer)
 592                + end_overshoot;
 593
 594            if start_excerpt.id == end_excerpt.id {
 595                buffer_edits
 596                    .entry(start_excerpt.buffer_id)
 597                    .or_insert(Vec::new())
 598                    .push(BufferEdit {
 599                        range: buffer_start..buffer_end,
 600                        new_text,
 601                        is_insertion: true,
 602                        original_indent_column,
 603                    });
 604            } else {
 605                edited_excerpt_ids.push(end_excerpt.id);
 606                let start_excerpt_range = buffer_start
 607                    ..start_excerpt
 608                        .range
 609                        .context
 610                        .end
 611                        .to_offset(&start_excerpt.buffer);
 612                let end_excerpt_range = end_excerpt
 613                    .range
 614                    .context
 615                    .start
 616                    .to_offset(&end_excerpt.buffer)
 617                    ..buffer_end;
 618                buffer_edits
 619                    .entry(start_excerpt.buffer_id)
 620                    .or_insert(Vec::new())
 621                    .push(BufferEdit {
 622                        range: start_excerpt_range,
 623                        new_text: new_text.clone(),
 624                        is_insertion: true,
 625                        original_indent_column,
 626                    });
 627                buffer_edits
 628                    .entry(end_excerpt.buffer_id)
 629                    .or_insert(Vec::new())
 630                    .push(BufferEdit {
 631                        range: end_excerpt_range,
 632                        new_text: new_text.clone(),
 633                        is_insertion: false,
 634                        original_indent_column,
 635                    });
 636
 637                cursor.seek(&range.start, Bias::Right, &());
 638                cursor.next(&());
 639                while let Some(excerpt) = cursor.item() {
 640                    if excerpt.id == end_excerpt.id {
 641                        break;
 642                    }
 643                    buffer_edits
 644                        .entry(excerpt.buffer_id)
 645                        .or_insert(Vec::new())
 646                        .push(BufferEdit {
 647                            range: excerpt.range.context.to_offset(&excerpt.buffer),
 648                            new_text: new_text.clone(),
 649                            is_insertion: false,
 650                            original_indent_column,
 651                        });
 652                    edited_excerpt_ids.push(excerpt.id);
 653                    cursor.next(&());
 654                }
 655            }
 656        }
 657
 658        drop(cursor);
 659        drop(snapshot);
 660        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 661        fn tail(
 662            this: &mut MultiBuffer,
 663            buffer_edits: HashMap<BufferId, Vec<BufferEdit>>,
 664            autoindent_mode: Option<AutoindentMode>,
 665            edited_excerpt_ids: Vec<ExcerptId>,
 666            cx: &mut ModelContext<MultiBuffer>,
 667        ) {
 668            for (buffer_id, mut edits) in buffer_edits {
 669                edits.sort_unstable_by_key(|edit| edit.range.start);
 670                this.buffers.borrow()[&buffer_id]
 671                    .buffer
 672                    .update(cx, |buffer, cx| {
 673                        let mut edits = edits.into_iter().peekable();
 674                        let mut insertions = Vec::new();
 675                        let mut original_indent_columns = Vec::new();
 676                        let mut deletions = Vec::new();
 677                        let empty_str: Arc<str> = Arc::default();
 678                        while let Some(BufferEdit {
 679                            mut range,
 680                            new_text,
 681                            mut is_insertion,
 682                            original_indent_column,
 683                        }) = edits.next()
 684                        {
 685                            while let Some(BufferEdit {
 686                                range: next_range,
 687                                is_insertion: next_is_insertion,
 688                                ..
 689                            }) = edits.peek()
 690                            {
 691                                if range.end >= next_range.start {
 692                                    range.end = cmp::max(next_range.end, range.end);
 693                                    is_insertion |= *next_is_insertion;
 694                                    edits.next();
 695                                } else {
 696                                    break;
 697                                }
 698                            }
 699
 700                            if is_insertion {
 701                                original_indent_columns.push(original_indent_column);
 702                                insertions.push((
 703                                    buffer.anchor_before(range.start)
 704                                        ..buffer.anchor_before(range.end),
 705                                    new_text.clone(),
 706                                ));
 707                            } else if !range.is_empty() {
 708                                deletions.push((
 709                                    buffer.anchor_before(range.start)
 710                                        ..buffer.anchor_before(range.end),
 711                                    empty_str.clone(),
 712                                ));
 713                            }
 714                        }
 715
 716                        let deletion_autoindent_mode =
 717                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 718                                Some(AutoindentMode::Block {
 719                                    original_indent_columns: Default::default(),
 720                                })
 721                            } else {
 722                                None
 723                            };
 724                        let insertion_autoindent_mode =
 725                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 726                                Some(AutoindentMode::Block {
 727                                    original_indent_columns,
 728                                })
 729                            } else {
 730                                None
 731                            };
 732
 733                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 734                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 735                    })
 736            }
 737
 738            cx.emit(Event::ExcerptsEdited {
 739                ids: edited_excerpt_ids,
 740            });
 741        }
 742        tail(self, buffer_edits, autoindent_mode, edited_excerpt_ids, cx);
 743    }
 744
 745    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 746        self.start_transaction_at(Instant::now(), cx)
 747    }
 748
 749    pub fn start_transaction_at(
 750        &mut self,
 751        now: Instant,
 752        cx: &mut ModelContext<Self>,
 753    ) -> Option<TransactionId> {
 754        if let Some(buffer) = self.as_singleton() {
 755            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 756        }
 757
 758        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 759            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 760        }
 761        self.history.start_transaction(now)
 762    }
 763
 764    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 765        self.end_transaction_at(Instant::now(), cx)
 766    }
 767
 768    pub fn end_transaction_at(
 769        &mut self,
 770        now: Instant,
 771        cx: &mut ModelContext<Self>,
 772    ) -> Option<TransactionId> {
 773        if let Some(buffer) = self.as_singleton() {
 774            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 775        }
 776
 777        let mut buffer_transactions = HashMap::default();
 778        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 779            if let Some(transaction_id) =
 780                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 781            {
 782                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
 783            }
 784        }
 785
 786        if self.history.end_transaction(now, buffer_transactions) {
 787            let transaction_id = self.history.group().unwrap();
 788            Some(transaction_id)
 789        } else {
 790            None
 791        }
 792    }
 793
 794    pub fn edited_ranges_for_transaction<D>(
 795        &self,
 796        transaction_id: TransactionId,
 797        cx: &AppContext,
 798    ) -> Vec<Range<D>>
 799    where
 800        D: TextDimension + Ord + Sub<D, Output = D>,
 801    {
 802        if let Some(buffer) = self.as_singleton() {
 803            return buffer
 804                .read(cx)
 805                .edited_ranges_for_transaction_id(transaction_id)
 806                .collect::<Vec<_>>();
 807        }
 808
 809        let Some(transaction) = self.history.transaction(transaction_id) else {
 810            return Vec::new();
 811        };
 812
 813        let mut ranges = Vec::new();
 814        let snapshot = self.read(cx);
 815        let buffers = self.buffers.borrow();
 816        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>();
 817
 818        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
 819            let Some(buffer_state) = buffers.get(&buffer_id) else {
 820                continue;
 821            };
 822
 823            let buffer = buffer_state.buffer.read(cx);
 824            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
 825                for excerpt_id in &buffer_state.excerpts {
 826                    cursor.seek(excerpt_id, Bias::Left, &());
 827                    if let Some(excerpt) = cursor.item() {
 828                        if excerpt.locator == *excerpt_id {
 829                            let excerpt_buffer_start =
 830                                excerpt.range.context.start.summary::<D>(buffer);
 831                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
 832                            let excerpt_range = excerpt_buffer_start.clone()..excerpt_buffer_end;
 833                            if excerpt_range.contains(&range.start)
 834                                && excerpt_range.contains(&range.end)
 835                            {
 836                                let excerpt_start = D::from_text_summary(&cursor.start().text);
 837
 838                                let mut start = excerpt_start.clone();
 839                                start.add_assign(&(range.start - excerpt_buffer_start.clone()));
 840                                let mut end = excerpt_start;
 841                                end.add_assign(&(range.end - excerpt_buffer_start));
 842
 843                                ranges.push(start..end);
 844                                break;
 845                            }
 846                        }
 847                    }
 848                }
 849            }
 850        }
 851
 852        ranges.sort_by_key(|range| range.start.clone());
 853        ranges
 854    }
 855
 856    pub fn merge_transactions(
 857        &mut self,
 858        transaction: TransactionId,
 859        destination: TransactionId,
 860        cx: &mut ModelContext<Self>,
 861    ) {
 862        if let Some(buffer) = self.as_singleton() {
 863            buffer.update(cx, |buffer, _| {
 864                buffer.merge_transactions(transaction, destination)
 865            });
 866        } else {
 867            if let Some(transaction) = self.history.forget(transaction) {
 868                if let Some(destination) = self.history.transaction_mut(destination) {
 869                    for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
 870                        if let Some(destination_buffer_transaction_id) =
 871                            destination.buffer_transactions.get(&buffer_id)
 872                        {
 873                            if let Some(state) = self.buffers.borrow().get(&buffer_id) {
 874                                state.buffer.update(cx, |buffer, _| {
 875                                    buffer.merge_transactions(
 876                                        buffer_transaction_id,
 877                                        *destination_buffer_transaction_id,
 878                                    )
 879                                });
 880                            }
 881                        } else {
 882                            destination
 883                                .buffer_transactions
 884                                .insert(buffer_id, buffer_transaction_id);
 885                        }
 886                    }
 887                }
 888            }
 889        }
 890    }
 891
 892    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 893        self.history.finalize_last_transaction();
 894        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 895            buffer.update(cx, |buffer, _| {
 896                buffer.finalize_last_transaction();
 897            });
 898        }
 899    }
 900
 901    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &mut ModelContext<Self>)
 902    where
 903        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
 904    {
 905        self.history
 906            .push_transaction(buffer_transactions, Instant::now(), cx);
 907        self.history.finalize_last_transaction();
 908    }
 909
 910    pub fn group_until_transaction(
 911        &mut self,
 912        transaction_id: TransactionId,
 913        cx: &mut ModelContext<Self>,
 914    ) {
 915        if let Some(buffer) = self.as_singleton() {
 916            buffer.update(cx, |buffer, _| {
 917                buffer.group_until_transaction(transaction_id)
 918            });
 919        } else {
 920            self.history.group_until(transaction_id);
 921        }
 922    }
 923
 924    pub fn set_active_selections(
 925        &mut self,
 926        selections: &[Selection<Anchor>],
 927        line_mode: bool,
 928        cursor_shape: CursorShape,
 929        cx: &mut ModelContext<Self>,
 930    ) {
 931        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
 932            Default::default();
 933        let snapshot = self.read(cx);
 934        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
 935        for selection in selections {
 936            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
 937            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
 938
 939            cursor.seek(&Some(start_locator), Bias::Left, &());
 940            while let Some(excerpt) = cursor.item() {
 941                if excerpt.locator > *end_locator {
 942                    break;
 943                }
 944
 945                let mut start = excerpt.range.context.start;
 946                let mut end = excerpt.range.context.end;
 947                if excerpt.id == selection.start.excerpt_id {
 948                    start = selection.start.text_anchor;
 949                }
 950                if excerpt.id == selection.end.excerpt_id {
 951                    end = selection.end.text_anchor;
 952                }
 953                selections_by_buffer
 954                    .entry(excerpt.buffer_id)
 955                    .or_default()
 956                    .push(Selection {
 957                        id: selection.id,
 958                        start,
 959                        end,
 960                        reversed: selection.reversed,
 961                        goal: selection.goal,
 962                    });
 963
 964                cursor.next(&());
 965            }
 966        }
 967
 968        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 969            if !selections_by_buffer.contains_key(buffer_id) {
 970                buffer_state
 971                    .buffer
 972                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 973            }
 974        }
 975
 976        for (buffer_id, mut selections) in selections_by_buffer {
 977            self.buffers.borrow()[&buffer_id]
 978                .buffer
 979                .update(cx, |buffer, cx| {
 980                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
 981                    let mut selections = selections.into_iter().peekable();
 982                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 983                        let mut selection = selections.next()?;
 984                        while let Some(next_selection) = selections.peek() {
 985                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
 986                                let next_selection = selections.next().unwrap();
 987                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
 988                                    selection.end = next_selection.end;
 989                                }
 990                            } else {
 991                                break;
 992                            }
 993                        }
 994                        Some(selection)
 995                    }));
 996                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
 997                });
 998        }
 999    }
1000
1001    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
1002        for buffer in self.buffers.borrow().values() {
1003            buffer
1004                .buffer
1005                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1006        }
1007    }
1008
1009    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
1010        let mut transaction_id = None;
1011        if let Some(buffer) = self.as_singleton() {
1012            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1013        } else {
1014            while let Some(transaction) = self.history.pop_undo() {
1015                let mut undone = false;
1016                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1017                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1018                        undone |= buffer.update(cx, |buffer, cx| {
1019                            let undo_to = *buffer_transaction_id;
1020                            if let Some(entry) = buffer.peek_undo_stack() {
1021                                *buffer_transaction_id = entry.transaction_id();
1022                            }
1023                            buffer.undo_to_transaction(undo_to, cx)
1024                        });
1025                    }
1026                }
1027
1028                if undone {
1029                    transaction_id = Some(transaction.id);
1030                    break;
1031                }
1032            }
1033        }
1034
1035        if let Some(transaction_id) = transaction_id {
1036            cx.emit(Event::TransactionUndone { transaction_id });
1037        }
1038
1039        transaction_id
1040    }
1041
1042    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
1043        if let Some(buffer) = self.as_singleton() {
1044            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1045        }
1046
1047        while let Some(transaction) = self.history.pop_redo() {
1048            let mut redone = false;
1049            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1050                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1051                    redone |= buffer.update(cx, |buffer, cx| {
1052                        let redo_to = *buffer_transaction_id;
1053                        if let Some(entry) = buffer.peek_redo_stack() {
1054                            *buffer_transaction_id = entry.transaction_id();
1055                        }
1056                        buffer.redo_to_transaction(redo_to, cx)
1057                    });
1058                }
1059            }
1060
1061            if redone {
1062                return Some(transaction.id);
1063            }
1064        }
1065
1066        None
1067    }
1068
1069    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut ModelContext<Self>) {
1070        if let Some(buffer) = self.as_singleton() {
1071            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1072        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1073            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1074                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1075                    buffer.update(cx, |buffer, cx| {
1076                        buffer.undo_transaction(*transaction_id, cx)
1077                    });
1078                }
1079            }
1080        }
1081    }
1082
1083    pub fn stream_excerpts_with_context_lines(
1084        &mut self,
1085        buffer: Model<Buffer>,
1086        ranges: Vec<Range<text::Anchor>>,
1087        context_line_count: u32,
1088        cx: &mut ModelContext<Self>,
1089    ) -> mpsc::Receiver<Range<Anchor>> {
1090        let (buffer_id, buffer_snapshot) =
1091            buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1092
1093        let (mut tx, rx) = mpsc::channel(256);
1094        cx.spawn(move |this, mut cx| async move {
1095            let mut excerpt_ranges = Vec::new();
1096            let mut range_counts = Vec::new();
1097            cx.background_executor()
1098                .scoped(|scope| {
1099                    scope.spawn(async {
1100                        let (ranges, counts) =
1101                            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1102                        excerpt_ranges = ranges;
1103                        range_counts = counts;
1104                    });
1105                })
1106                .await;
1107
1108            let mut ranges = ranges.into_iter();
1109            let mut range_counts = range_counts.into_iter();
1110            for excerpt_ranges in excerpt_ranges.chunks(100) {
1111                let excerpt_ids = match this.update(&mut cx, |this, cx| {
1112                    this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1113                }) {
1114                    Ok(excerpt_ids) => excerpt_ids,
1115                    Err(_) => return,
1116                };
1117
1118                for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.by_ref())
1119                {
1120                    for range in ranges.by_ref().take(range_count) {
1121                        let start = Anchor {
1122                            buffer_id: Some(buffer_id),
1123                            excerpt_id,
1124                            text_anchor: range.start,
1125                        };
1126                        let end = Anchor {
1127                            buffer_id: Some(buffer_id),
1128                            excerpt_id,
1129                            text_anchor: range.end,
1130                        };
1131                        if tx.send(start..end).await.is_err() {
1132                            break;
1133                        }
1134                    }
1135                }
1136            }
1137        })
1138        .detach();
1139
1140        rx
1141    }
1142
1143    pub fn push_excerpts<O>(
1144        &mut self,
1145        buffer: Model<Buffer>,
1146        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1147        cx: &mut ModelContext<Self>,
1148    ) -> Vec<ExcerptId>
1149    where
1150        O: text::ToOffset,
1151    {
1152        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1153    }
1154
1155    pub fn push_excerpts_with_context_lines<O>(
1156        &mut self,
1157        buffer: Model<Buffer>,
1158        ranges: Vec<Range<O>>,
1159        context_line_count: u32,
1160        cx: &mut ModelContext<Self>,
1161    ) -> Vec<Range<Anchor>>
1162    where
1163        O: text::ToPoint + text::ToOffset,
1164    {
1165        let buffer_id = buffer.read(cx).remote_id();
1166        let buffer_snapshot = buffer.read(cx).snapshot();
1167        let (excerpt_ranges, range_counts) =
1168            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1169
1170        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1171
1172        let mut anchor_ranges = Vec::new();
1173        let mut ranges = ranges.into_iter();
1174        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1175            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1176                let start = Anchor {
1177                    buffer_id: Some(buffer_id),
1178                    excerpt_id,
1179                    text_anchor: buffer_snapshot.anchor_after(range.start),
1180                };
1181                let end = Anchor {
1182                    buffer_id: Some(buffer_id),
1183                    excerpt_id,
1184                    text_anchor: buffer_snapshot.anchor_after(range.end),
1185                };
1186                start..end
1187            }))
1188        }
1189        anchor_ranges
1190    }
1191
1192    pub fn insert_excerpts_after<O>(
1193        &mut self,
1194        prev_excerpt_id: ExcerptId,
1195        buffer: Model<Buffer>,
1196        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1197        cx: &mut ModelContext<Self>,
1198    ) -> Vec<ExcerptId>
1199    where
1200        O: text::ToOffset,
1201    {
1202        let mut ids = Vec::new();
1203        let mut next_excerpt_id =
1204            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1205                last_entry.id.0 + 1
1206            } else {
1207                1
1208            };
1209        self.insert_excerpts_with_ids_after(
1210            prev_excerpt_id,
1211            buffer,
1212            ranges.into_iter().map(|range| {
1213                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1214                ids.push(id);
1215                (id, range)
1216            }),
1217            cx,
1218        );
1219        ids
1220    }
1221
1222    pub fn insert_excerpts_with_ids_after<O>(
1223        &mut self,
1224        prev_excerpt_id: ExcerptId,
1225        buffer: Model<Buffer>,
1226        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1227        cx: &mut ModelContext<Self>,
1228    ) where
1229        O: text::ToOffset,
1230    {
1231        assert_eq!(self.history.transaction_depth, 0);
1232        let mut ranges = ranges.into_iter().peekable();
1233        if ranges.peek().is_none() {
1234            return Default::default();
1235        }
1236
1237        self.sync(cx);
1238
1239        let buffer_id = buffer.read(cx).remote_id();
1240        let buffer_snapshot = buffer.read(cx).snapshot();
1241
1242        let mut buffers = self.buffers.borrow_mut();
1243        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1244            last_version: buffer_snapshot.version().clone(),
1245            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1246            excerpts: Default::default(),
1247            _subscriptions: [
1248                cx.observe(&buffer, |_, _, cx| cx.notify()),
1249                cx.subscribe(&buffer, Self::on_buffer_event),
1250            ],
1251            buffer: buffer.clone(),
1252        });
1253
1254        let mut snapshot = self.snapshot.borrow_mut();
1255
1256        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1257        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1258        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1259        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1260        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1261
1262        let edit_start = new_excerpts.summary().text.len;
1263        new_excerpts.update_last(
1264            |excerpt| {
1265                excerpt.has_trailing_newline = true;
1266            },
1267            &(),
1268        );
1269
1270        let next_locator = if let Some(excerpt) = cursor.item() {
1271            excerpt.locator.clone()
1272        } else {
1273            Locator::max()
1274        };
1275
1276        let mut excerpts = Vec::new();
1277        while let Some((id, range)) = ranges.next() {
1278            let locator = Locator::between(&prev_locator, &next_locator);
1279            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1280                buffer_state.excerpts.insert(ix, locator.clone());
1281            }
1282            let range = ExcerptRange {
1283                context: buffer_snapshot.anchor_before(&range.context.start)
1284                    ..buffer_snapshot.anchor_after(&range.context.end),
1285                primary: range.primary.map(|primary| {
1286                    buffer_snapshot.anchor_before(&primary.start)
1287                        ..buffer_snapshot.anchor_after(&primary.end)
1288                }),
1289            };
1290            excerpts.push((id, range.clone()));
1291            let excerpt = Excerpt::new(
1292                id,
1293                locator.clone(),
1294                buffer_id,
1295                buffer_snapshot.clone(),
1296                range,
1297                ranges.peek().is_some() || cursor.item().is_some(),
1298            );
1299            new_excerpts.push(excerpt, &());
1300            prev_locator = locator.clone();
1301
1302            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1303                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1304            }
1305            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1306        }
1307
1308        let edit_end = new_excerpts.summary().text.len;
1309
1310        let suffix = cursor.suffix(&());
1311        let changed_trailing_excerpt = suffix.is_empty();
1312        new_excerpts.append(suffix, &());
1313        drop(cursor);
1314        snapshot.excerpts = new_excerpts;
1315        snapshot.excerpt_ids = new_excerpt_ids;
1316        if changed_trailing_excerpt {
1317            snapshot.trailing_excerpt_update_count += 1;
1318        }
1319
1320        self.subscriptions.publish_mut([Edit {
1321            old: edit_start..edit_start,
1322            new: edit_start..edit_end,
1323        }]);
1324        cx.emit(Event::Edited {
1325            singleton_buffer_edited: false,
1326        });
1327        cx.emit(Event::ExcerptsAdded {
1328            buffer,
1329            predecessor: prev_excerpt_id,
1330            excerpts,
1331        });
1332        cx.notify();
1333    }
1334
1335    pub fn clear(&mut self, cx: &mut ModelContext<Self>) {
1336        self.sync(cx);
1337        let ids = self.excerpt_ids();
1338        self.buffers.borrow_mut().clear();
1339        let mut snapshot = self.snapshot.borrow_mut();
1340        let prev_len = snapshot.len();
1341        snapshot.excerpts = Default::default();
1342        snapshot.trailing_excerpt_update_count += 1;
1343        snapshot.is_dirty = false;
1344        snapshot.has_conflict = false;
1345
1346        self.subscriptions.publish_mut([Edit {
1347            old: 0..prev_len,
1348            new: 0..0,
1349        }]);
1350        cx.emit(Event::Edited {
1351            singleton_buffer_edited: false,
1352        });
1353        cx.emit(Event::ExcerptsRemoved { ids });
1354        cx.notify();
1355    }
1356
1357    pub fn excerpts_for_buffer(
1358        &self,
1359        buffer: &Model<Buffer>,
1360        cx: &AppContext,
1361    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1362        let mut excerpts = Vec::new();
1363        let snapshot = self.read(cx);
1364        let buffers = self.buffers.borrow();
1365        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1366        for locator in buffers
1367            .get(&buffer.read(cx).remote_id())
1368            .map(|state| &state.excerpts)
1369            .into_iter()
1370            .flatten()
1371        {
1372            cursor.seek_forward(&Some(locator), Bias::Left, &());
1373            if let Some(excerpt) = cursor.item() {
1374                if excerpt.locator == *locator {
1375                    excerpts.push((excerpt.id, excerpt.range.clone()));
1376                }
1377            }
1378        }
1379
1380        excerpts
1381    }
1382
1383    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1384        self.snapshot
1385            .borrow()
1386            .excerpts
1387            .iter()
1388            .map(|entry| entry.buffer_id)
1389            .collect()
1390    }
1391
1392    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1393        self.snapshot
1394            .borrow()
1395            .excerpts
1396            .iter()
1397            .map(|entry| entry.id)
1398            .collect()
1399    }
1400
1401    pub fn excerpt_containing(
1402        &self,
1403        position: impl ToOffset,
1404        cx: &AppContext,
1405    ) -> Option<(ExcerptId, Model<Buffer>, Range<text::Anchor>)> {
1406        let snapshot = self.read(cx);
1407        let position = position.to_offset(&snapshot);
1408
1409        let mut cursor = snapshot.excerpts.cursor::<usize>();
1410        cursor.seek(&position, Bias::Right, &());
1411        cursor
1412            .item()
1413            .or_else(|| snapshot.excerpts.last())
1414            .map(|excerpt| {
1415                (
1416                    excerpt.id,
1417                    self.buffers
1418                        .borrow()
1419                        .get(&excerpt.buffer_id)
1420                        .unwrap()
1421                        .buffer
1422                        .clone(),
1423                    excerpt.range.context.clone(),
1424                )
1425            })
1426    }
1427
1428    // If point is at the end of the buffer, the last excerpt is returned
1429    pub fn point_to_buffer_offset<T: ToOffset>(
1430        &self,
1431        point: T,
1432        cx: &AppContext,
1433    ) -> Option<(Model<Buffer>, usize, ExcerptId)> {
1434        let snapshot = self.read(cx);
1435        let offset = point.to_offset(&snapshot);
1436        let mut cursor = snapshot.excerpts.cursor::<usize>();
1437        cursor.seek(&offset, Bias::Right, &());
1438        if cursor.item().is_none() {
1439            cursor.prev(&());
1440        }
1441
1442        cursor.item().map(|excerpt| {
1443            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1444            let buffer_point = excerpt_start + offset - *cursor.start();
1445            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1446
1447            (buffer, buffer_point, excerpt.id)
1448        })
1449    }
1450
1451    pub fn range_to_buffer_ranges<T: ToOffset>(
1452        &self,
1453        range: Range<T>,
1454        cx: &AppContext,
1455    ) -> Vec<(Model<Buffer>, Range<usize>, ExcerptId)> {
1456        let snapshot = self.read(cx);
1457        let start = range.start.to_offset(&snapshot);
1458        let end = range.end.to_offset(&snapshot);
1459
1460        let mut result = Vec::new();
1461        let mut cursor = snapshot.excerpts.cursor::<usize>();
1462        cursor.seek(&start, Bias::Right, &());
1463        if cursor.item().is_none() {
1464            cursor.prev(&());
1465        }
1466
1467        while let Some(excerpt) = cursor.item() {
1468            if *cursor.start() > end {
1469                break;
1470            }
1471
1472            let mut end_before_newline = cursor.end(&());
1473            if excerpt.has_trailing_newline {
1474                end_before_newline -= 1;
1475            }
1476            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1477            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
1478            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
1479            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1480            result.push((buffer, start..end, excerpt.id));
1481            cursor.next(&());
1482        }
1483
1484        result
1485    }
1486
1487    pub fn remove_excerpts(
1488        &mut self,
1489        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1490        cx: &mut ModelContext<Self>,
1491    ) {
1492        self.sync(cx);
1493        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1494        if ids.is_empty() {
1495            return;
1496        }
1497
1498        let mut buffers = self.buffers.borrow_mut();
1499        let mut snapshot = self.snapshot.borrow_mut();
1500        let mut new_excerpts = SumTree::new();
1501        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1502        let mut edits = Vec::new();
1503        let mut excerpt_ids = ids.iter().copied().peekable();
1504
1505        while let Some(excerpt_id) = excerpt_ids.next() {
1506            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1507            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1508            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1509
1510            if let Some(mut excerpt) = cursor.item() {
1511                if excerpt.id != excerpt_id {
1512                    continue;
1513                }
1514                let mut old_start = cursor.start().1;
1515
1516                // Skip over the removed excerpt.
1517                'remove_excerpts: loop {
1518                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
1519                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1520                        if buffer_state.excerpts.is_empty() {
1521                            buffers.remove(&excerpt.buffer_id);
1522                        }
1523                    }
1524                    cursor.next(&());
1525
1526                    // Skip over any subsequent excerpts that are also removed.
1527                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1528                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1529                        if let Some(next_excerpt) = cursor.item() {
1530                            if next_excerpt.locator == *next_locator {
1531                                excerpt_ids.next();
1532                                excerpt = next_excerpt;
1533                                continue 'remove_excerpts;
1534                            }
1535                        }
1536                    }
1537
1538                    break;
1539                }
1540
1541                // When removing the last excerpt, remove the trailing newline from
1542                // the previous excerpt.
1543                if cursor.item().is_none() && old_start > 0 {
1544                    old_start -= 1;
1545                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
1546                }
1547
1548                // Push an edit for the removal of this run of excerpts.
1549                let old_end = cursor.start().1;
1550                let new_start = new_excerpts.summary().text.len;
1551                edits.push(Edit {
1552                    old: old_start..old_end,
1553                    new: new_start..new_start,
1554                });
1555            }
1556        }
1557        let suffix = cursor.suffix(&());
1558        let changed_trailing_excerpt = suffix.is_empty();
1559        new_excerpts.append(suffix, &());
1560        drop(cursor);
1561        snapshot.excerpts = new_excerpts;
1562
1563        if changed_trailing_excerpt {
1564            snapshot.trailing_excerpt_update_count += 1;
1565        }
1566
1567        self.subscriptions.publish_mut(edits);
1568        cx.emit(Event::Edited {
1569            singleton_buffer_edited: false,
1570        });
1571        cx.emit(Event::ExcerptsRemoved { ids });
1572        cx.notify();
1573    }
1574
1575    pub fn wait_for_anchors<'a>(
1576        &self,
1577        anchors: impl 'a + Iterator<Item = Anchor>,
1578        cx: &mut ModelContext<Self>,
1579    ) -> impl 'static + Future<Output = Result<()>> {
1580        let borrow = self.buffers.borrow();
1581        let mut error = None;
1582        let mut futures = Vec::new();
1583        for anchor in anchors {
1584            if let Some(buffer_id) = anchor.buffer_id {
1585                if let Some(buffer) = borrow.get(&buffer_id) {
1586                    buffer.buffer.update(cx, |buffer, _| {
1587                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1588                    });
1589                } else {
1590                    error = Some(anyhow!(
1591                        "buffer {buffer_id} is not part of this multi-buffer"
1592                    ));
1593                    break;
1594                }
1595            }
1596        }
1597        async move {
1598            if let Some(error) = error {
1599                Err(error)?;
1600            }
1601            for future in futures {
1602                future.await?;
1603            }
1604            Ok(())
1605        }
1606    }
1607
1608    pub fn text_anchor_for_position<T: ToOffset>(
1609        &self,
1610        position: T,
1611        cx: &AppContext,
1612    ) -> Option<(Model<Buffer>, language::Anchor)> {
1613        let snapshot = self.read(cx);
1614        let anchor = snapshot.anchor_before(position);
1615        let buffer = self
1616            .buffers
1617            .borrow()
1618            .get(&anchor.buffer_id?)?
1619            .buffer
1620            .clone();
1621        Some((buffer, anchor.text_anchor))
1622    }
1623
1624    fn on_buffer_event(
1625        &mut self,
1626        buffer: Model<Buffer>,
1627        event: &language::Event,
1628        cx: &mut ModelContext<Self>,
1629    ) {
1630        cx.emit(match event {
1631            language::Event::Edited => Event::Edited {
1632                singleton_buffer_edited: true,
1633            },
1634            language::Event::DirtyChanged => Event::DirtyChanged,
1635            language::Event::Saved => Event::Saved,
1636            language::Event::FileHandleChanged => Event::FileHandleChanged,
1637            language::Event::Reloaded => Event::Reloaded,
1638            language::Event::DiffBaseChanged => Event::DiffBaseChanged,
1639            language::Event::DiffUpdated => Event::DiffUpdated { buffer },
1640            language::Event::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1641            language::Event::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1642            language::Event::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1643            language::Event::Closed => Event::Closed,
1644            language::Event::CapabilityChanged => {
1645                self.capability = buffer.read(cx).capability();
1646                Event::CapabilityChanged
1647            }
1648
1649            //
1650            language::Event::Operation(_) => return,
1651        });
1652    }
1653
1654    pub fn all_buffers(&self) -> HashSet<Model<Buffer>> {
1655        self.buffers
1656            .borrow()
1657            .values()
1658            .map(|state| state.buffer.clone())
1659            .collect()
1660    }
1661
1662    pub fn buffer(&self, buffer_id: BufferId) -> Option<Model<Buffer>> {
1663        self.buffers
1664            .borrow()
1665            .get(&buffer_id)
1666            .map(|state| state.buffer.clone())
1667    }
1668
1669    pub fn language_at<T: ToOffset>(&self, point: T, cx: &AppContext) -> Option<Arc<Language>> {
1670        self.point_to_buffer_offset(point, cx)
1671            .and_then(|(buffer, offset, _)| buffer.read(cx).language_at(offset))
1672    }
1673
1674    pub fn settings_at<'a, T: ToOffset>(
1675        &self,
1676        point: T,
1677        cx: &'a AppContext,
1678    ) -> &'a LanguageSettings {
1679        let mut language = None;
1680        let mut file = None;
1681        if let Some((buffer, offset, _)) = self.point_to_buffer_offset(point, cx) {
1682            let buffer = buffer.read(cx);
1683            language = buffer.language_at(offset);
1684            file = buffer.file();
1685        }
1686        language_settings(language.as_ref(), file, cx)
1687    }
1688
1689    pub fn for_each_buffer(&self, mut f: impl FnMut(&Model<Buffer>)) {
1690        self.buffers
1691            .borrow()
1692            .values()
1693            .for_each(|state| f(&state.buffer))
1694    }
1695
1696    pub fn title<'a>(&'a self, cx: &'a AppContext) -> Cow<'a, str> {
1697        if let Some(title) = self.title.as_ref() {
1698            return title.into();
1699        }
1700
1701        if let Some(buffer) = self.as_singleton() {
1702            if let Some(file) = buffer.read(cx).file() {
1703                return file.file_name(cx).to_string_lossy();
1704            }
1705        }
1706
1707        "untitled".into()
1708    }
1709
1710    pub fn set_title(&mut self, title: String, cx: &mut ModelContext<Self>) {
1711        self.title = Some(title);
1712        cx.notify();
1713    }
1714
1715    #[cfg(any(test, feature = "test-support"))]
1716    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1717        self.as_singleton().unwrap().read(cx).is_parsing()
1718    }
1719
1720    pub fn expand_excerpts(
1721        &mut self,
1722        ids: impl IntoIterator<Item = ExcerptId>,
1723        line_count: u32,
1724        direction: ExpandExcerptDirection,
1725        cx: &mut ModelContext<Self>,
1726    ) {
1727        if line_count == 0 {
1728            return;
1729        }
1730        self.sync(cx);
1731
1732        let ids = ids.into_iter().collect::<Vec<_>>();
1733        let snapshot = self.snapshot(cx);
1734        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
1735        let mut new_excerpts = SumTree::new();
1736        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1737        let mut edits = Vec::<Edit<usize>>::new();
1738
1739        for locator in &locators {
1740            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
1741            new_excerpts.append(prefix, &());
1742
1743            let mut excerpt = cursor.item().unwrap().clone();
1744            let old_text_len = excerpt.text_summary.len;
1745
1746            let up_line_count = if direction.should_expand_up() {
1747                line_count
1748            } else {
1749                0
1750            };
1751
1752            let start_row = excerpt
1753                .range
1754                .context
1755                .start
1756                .to_point(&excerpt.buffer)
1757                .row
1758                .saturating_sub(up_line_count);
1759            let start_point = Point::new(start_row, 0);
1760            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
1761
1762            let down_line_count = if direction.should_expand_down() {
1763                line_count
1764            } else {
1765                0
1766            };
1767
1768            let mut end_point = excerpt.buffer.clip_point(
1769                excerpt.range.context.end.to_point(&excerpt.buffer)
1770                    + Point::new(down_line_count, 0),
1771                Bias::Left,
1772            );
1773            end_point.column = excerpt.buffer.line_len(end_point.row);
1774            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
1775            excerpt.max_buffer_row = end_point.row;
1776
1777            excerpt.text_summary = excerpt
1778                .buffer
1779                .text_summary_for_range(excerpt.range.context.clone());
1780
1781            let new_start_offset = new_excerpts.summary().text.len;
1782            let old_start_offset = cursor.start().1;
1783            let edit = Edit {
1784                old: old_start_offset..old_start_offset + old_text_len,
1785                new: new_start_offset..new_start_offset + excerpt.text_summary.len,
1786            };
1787
1788            if let Some(last_edit) = edits.last_mut() {
1789                if last_edit.old.end == edit.old.start {
1790                    last_edit.old.end = edit.old.end;
1791                    last_edit.new.end = edit.new.end;
1792                } else {
1793                    edits.push(edit);
1794                }
1795            } else {
1796                edits.push(edit);
1797            }
1798
1799            new_excerpts.push(excerpt, &());
1800
1801            cursor.next(&());
1802        }
1803
1804        new_excerpts.append(cursor.suffix(&()), &());
1805
1806        drop(cursor);
1807        self.snapshot.borrow_mut().excerpts = new_excerpts;
1808
1809        self.subscriptions.publish_mut(edits);
1810        cx.emit(Event::Edited {
1811            singleton_buffer_edited: false,
1812        });
1813        cx.emit(Event::ExcerptsExpanded { ids });
1814        cx.notify();
1815    }
1816
1817    fn sync(&self, cx: &AppContext) {
1818        let mut snapshot = self.snapshot.borrow_mut();
1819        let mut excerpts_to_edit = Vec::new();
1820        let mut non_text_state_updated = false;
1821        let mut is_dirty = false;
1822        let mut has_conflict = false;
1823        let mut edited = false;
1824        let mut buffers = self.buffers.borrow_mut();
1825        for buffer_state in buffers.values_mut() {
1826            let buffer = buffer_state.buffer.read(cx);
1827            let version = buffer.version();
1828            let non_text_state_update_count = buffer.non_text_state_update_count();
1829
1830            let buffer_edited = version.changed_since(&buffer_state.last_version);
1831            let buffer_non_text_state_updated =
1832                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
1833            if buffer_edited || buffer_non_text_state_updated {
1834                buffer_state.last_version = version;
1835                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
1836                excerpts_to_edit.extend(
1837                    buffer_state
1838                        .excerpts
1839                        .iter()
1840                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
1841                );
1842            }
1843
1844            edited |= buffer_edited;
1845            non_text_state_updated |= buffer_non_text_state_updated;
1846            is_dirty |= buffer.is_dirty();
1847            has_conflict |= buffer.has_conflict();
1848        }
1849        if edited {
1850            snapshot.edit_count += 1;
1851        }
1852        if non_text_state_updated {
1853            snapshot.non_text_state_update_count += 1;
1854        }
1855        snapshot.is_dirty = is_dirty;
1856        snapshot.has_conflict = has_conflict;
1857
1858        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
1859
1860        let mut edits = Vec::new();
1861        let mut new_excerpts = SumTree::new();
1862        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1863
1864        for (locator, buffer, buffer_edited) in excerpts_to_edit {
1865            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1866            let old_excerpt = cursor.item().unwrap();
1867            let buffer = buffer.read(cx);
1868            let buffer_id = buffer.remote_id();
1869
1870            let mut new_excerpt;
1871            if buffer_edited {
1872                edits.extend(
1873                    buffer
1874                        .edits_since_in_range::<usize>(
1875                            old_excerpt.buffer.version(),
1876                            old_excerpt.range.context.clone(),
1877                        )
1878                        .map(|mut edit| {
1879                            let excerpt_old_start = cursor.start().1;
1880                            let excerpt_new_start = new_excerpts.summary().text.len;
1881                            edit.old.start += excerpt_old_start;
1882                            edit.old.end += excerpt_old_start;
1883                            edit.new.start += excerpt_new_start;
1884                            edit.new.end += excerpt_new_start;
1885                            edit
1886                        }),
1887                );
1888
1889                new_excerpt = Excerpt::new(
1890                    old_excerpt.id,
1891                    locator.clone(),
1892                    buffer_id,
1893                    buffer.snapshot(),
1894                    old_excerpt.range.clone(),
1895                    old_excerpt.has_trailing_newline,
1896                );
1897            } else {
1898                new_excerpt = old_excerpt.clone();
1899                new_excerpt.buffer = buffer.snapshot();
1900            }
1901
1902            new_excerpts.push(new_excerpt, &());
1903            cursor.next(&());
1904        }
1905        new_excerpts.append(cursor.suffix(&()), &());
1906
1907        drop(cursor);
1908        snapshot.excerpts = new_excerpts;
1909
1910        self.subscriptions.publish(edits);
1911    }
1912}
1913
1914#[cfg(any(test, feature = "test-support"))]
1915impl MultiBuffer {
1916    pub fn build_simple(text: &str, cx: &mut gpui::AppContext) -> Model<Self> {
1917        let buffer = cx.new_model(|cx| Buffer::local(text, cx));
1918        cx.new_model(|cx| Self::singleton(buffer, cx))
1919    }
1920
1921    pub fn build_multi<const COUNT: usize>(
1922        excerpts: [(&str, Vec<Range<Point>>); COUNT],
1923        cx: &mut gpui::AppContext,
1924    ) -> Model<Self> {
1925        let multi = cx.new_model(|_| Self::new(0, Capability::ReadWrite));
1926        for (text, ranges) in excerpts {
1927            let buffer = cx.new_model(|cx| Buffer::local(text, cx));
1928            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
1929                context: range,
1930                primary: None,
1931            });
1932            multi.update(cx, |multi, cx| {
1933                multi.push_excerpts(buffer, excerpt_ranges, cx)
1934            });
1935        }
1936
1937        multi
1938    }
1939
1940    pub fn build_from_buffer(buffer: Model<Buffer>, cx: &mut gpui::AppContext) -> Model<Self> {
1941        cx.new_model(|cx| Self::singleton(buffer, cx))
1942    }
1943
1944    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::AppContext) -> Model<Self> {
1945        cx.new_model(|cx| {
1946            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
1947            let mutation_count = rng.gen_range(1..=5);
1948            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
1949            multibuffer
1950        })
1951    }
1952
1953    pub fn randomly_edit(
1954        &mut self,
1955        rng: &mut impl rand::Rng,
1956        edit_count: usize,
1957        cx: &mut ModelContext<Self>,
1958    ) {
1959        use util::RandomCharIter;
1960
1961        let snapshot = self.read(cx);
1962        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
1963        let mut last_end = None;
1964        for _ in 0..edit_count {
1965            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
1966                break;
1967            }
1968
1969            let new_start = last_end.map_or(0, |last_end| last_end + 1);
1970            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
1971            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
1972            last_end = Some(end);
1973
1974            let mut range = start..end;
1975            if rng.gen_bool(0.2) {
1976                mem::swap(&mut range.start, &mut range.end);
1977            }
1978
1979            let new_text_len = rng.gen_range(0..10);
1980            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1981
1982            edits.push((range, new_text.into()));
1983        }
1984        log::info!("mutating multi-buffer with {:?}", edits);
1985        drop(snapshot);
1986
1987        self.edit(edits, None, cx);
1988    }
1989
1990    pub fn randomly_edit_excerpts(
1991        &mut self,
1992        rng: &mut impl rand::Rng,
1993        mutation_count: usize,
1994        cx: &mut ModelContext<Self>,
1995    ) {
1996        use rand::prelude::*;
1997        use std::env;
1998        use util::RandomCharIter;
1999
2000        let max_excerpts = env::var("MAX_EXCERPTS")
2001            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
2002            .unwrap_or(5);
2003
2004        let mut buffers = Vec::new();
2005        for _ in 0..mutation_count {
2006            if rng.gen_bool(0.05) {
2007                log::info!("Clearing multi-buffer");
2008                self.clear(cx);
2009                continue;
2010            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
2011                let ids = self.excerpt_ids();
2012                let mut excerpts = HashSet::default();
2013                for _ in 0..rng.gen_range(0..ids.len()) {
2014                    excerpts.extend(ids.choose(rng).copied());
2015                }
2016
2017                let line_count = rng.gen_range(0..5);
2018
2019                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
2020
2021                self.expand_excerpts(
2022                    excerpts.iter().cloned(),
2023                    line_count,
2024                    ExpandExcerptDirection::UpAndDown,
2025                    cx,
2026                );
2027                continue;
2028            }
2029
2030            let excerpt_ids = self.excerpt_ids();
2031            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
2032                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
2033                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
2034                    buffers.push(cx.new_model(|cx| Buffer::local(text, cx)));
2035                    let buffer = buffers.last().unwrap().read(cx);
2036                    log::info!(
2037                        "Creating new buffer {} with text: {:?}",
2038                        buffer.remote_id(),
2039                        buffer.text()
2040                    );
2041                    buffers.last().unwrap().clone()
2042                } else {
2043                    self.buffers
2044                        .borrow()
2045                        .values()
2046                        .choose(rng)
2047                        .unwrap()
2048                        .buffer
2049                        .clone()
2050                };
2051
2052                let buffer = buffer_handle.read(cx);
2053                let buffer_text = buffer.text();
2054                let ranges = (0..rng.gen_range(0..5))
2055                    .map(|_| {
2056                        let end_ix =
2057                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
2058                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
2059                        ExcerptRange {
2060                            context: start_ix..end_ix,
2061                            primary: None,
2062                        }
2063                    })
2064                    .collect::<Vec<_>>();
2065                log::info!(
2066                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
2067                    buffer_handle.read(cx).remote_id(),
2068                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
2069                    ranges
2070                        .iter()
2071                        .map(|r| &buffer_text[r.context.clone()])
2072                        .collect::<Vec<_>>()
2073                );
2074
2075                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
2076                log::info!("Inserted with ids: {:?}", excerpt_id);
2077            } else {
2078                let remove_count = rng.gen_range(1..=excerpt_ids.len());
2079                let mut excerpts_to_remove = excerpt_ids
2080                    .choose_multiple(rng, remove_count)
2081                    .cloned()
2082                    .collect::<Vec<_>>();
2083                let snapshot = self.snapshot.borrow();
2084                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
2085                drop(snapshot);
2086                log::info!("Removing excerpts {:?}", excerpts_to_remove);
2087                self.remove_excerpts(excerpts_to_remove, cx);
2088            }
2089        }
2090    }
2091
2092    pub fn randomly_mutate(
2093        &mut self,
2094        rng: &mut impl rand::Rng,
2095        mutation_count: usize,
2096        cx: &mut ModelContext<Self>,
2097    ) {
2098        use rand::prelude::*;
2099
2100        if rng.gen_bool(0.7) || self.singleton {
2101            let buffer = self
2102                .buffers
2103                .borrow()
2104                .values()
2105                .choose(rng)
2106                .map(|state| state.buffer.clone());
2107
2108            if let Some(buffer) = buffer {
2109                buffer.update(cx, |buffer, cx| {
2110                    if rng.gen() {
2111                        buffer.randomly_edit(rng, mutation_count, cx);
2112                    } else {
2113                        buffer.randomly_undo_redo(rng, cx);
2114                    }
2115                });
2116            } else {
2117                self.randomly_edit(rng, mutation_count, cx);
2118            }
2119        } else {
2120            self.randomly_edit_excerpts(rng, mutation_count, cx);
2121        }
2122
2123        self.check_invariants(cx);
2124    }
2125
2126    fn check_invariants(&self, cx: &mut ModelContext<Self>) {
2127        let snapshot = self.read(cx);
2128        let excerpts = snapshot.excerpts.items(&());
2129        let excerpt_ids = snapshot.excerpt_ids.items(&());
2130
2131        for (ix, excerpt) in excerpts.iter().enumerate() {
2132            if ix == 0 {
2133                if excerpt.locator <= Locator::min() {
2134                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
2135                }
2136            } else {
2137                if excerpt.locator <= excerpts[ix - 1].locator {
2138                    panic!("excerpts are out-of-order: {:?}", excerpts);
2139                }
2140            }
2141        }
2142
2143        for (ix, entry) in excerpt_ids.iter().enumerate() {
2144            if ix == 0 {
2145                if entry.id.cmp(&ExcerptId::min(), &snapshot).is_le() {
2146                    panic!("invalid first excerpt id {:?}", entry.id);
2147                }
2148            } else {
2149                if entry.id <= excerpt_ids[ix - 1].id {
2150                    panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
2151                }
2152            }
2153        }
2154    }
2155}
2156
2157impl EventEmitter<Event> for MultiBuffer {}
2158
2159impl MultiBufferSnapshot {
2160    pub fn text(&self) -> String {
2161        self.chunks(0..self.len(), false)
2162            .map(|chunk| chunk.text)
2163            .collect()
2164    }
2165
2166    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
2167        let mut offset = position.to_offset(self);
2168        let mut cursor = self.excerpts.cursor::<usize>();
2169        cursor.seek(&offset, Bias::Left, &());
2170        let mut excerpt_chunks = cursor.item().map(|excerpt| {
2171            let end_before_footer = cursor.start() + excerpt.text_summary.len;
2172            let start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2173            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
2174            excerpt.buffer.reversed_chunks_in_range(start..end)
2175        });
2176        iter::from_fn(move || {
2177            if offset == *cursor.start() {
2178                cursor.prev(&());
2179                let excerpt = cursor.item()?;
2180                excerpt_chunks = Some(
2181                    excerpt
2182                        .buffer
2183                        .reversed_chunks_in_range(excerpt.range.context.clone()),
2184                );
2185            }
2186
2187            let excerpt = cursor.item().unwrap();
2188            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
2189                offset -= 1;
2190                Some("\n")
2191            } else {
2192                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
2193                offset -= chunk.len();
2194                Some(chunk)
2195            }
2196        })
2197        .flat_map(|c| c.chars().rev())
2198    }
2199
2200    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
2201        let offset = position.to_offset(self);
2202        self.text_for_range(offset..self.len())
2203            .flat_map(|chunk| chunk.chars())
2204    }
2205
2206    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
2207        self.chunks(range, false).map(|chunk| chunk.text)
2208    }
2209
2210    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
2211        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
2212            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
2213    }
2214
2215    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
2216    where
2217        T: ToOffset,
2218    {
2219        let position = position.to_offset(self);
2220        position == self.clip_offset(position, Bias::Left)
2221            && self
2222                .bytes_in_range(position..self.len())
2223                .flatten()
2224                .copied()
2225                .take(needle.len())
2226                .eq(needle.bytes())
2227    }
2228
2229    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
2230        let mut start = start.to_offset(self);
2231        let mut end = start;
2232        let mut next_chars = self.chars_at(start).peekable();
2233        let mut prev_chars = self.reversed_chars_at(start).peekable();
2234
2235        let scope = self.language_scope_at(start);
2236        let kind = |c| char_kind(&scope, c);
2237        let word_kind = cmp::max(
2238            prev_chars.peek().copied().map(kind),
2239            next_chars.peek().copied().map(kind),
2240        );
2241
2242        for ch in prev_chars {
2243            if Some(kind(ch)) == word_kind && ch != '\n' {
2244                start -= ch.len_utf8();
2245            } else {
2246                break;
2247            }
2248        }
2249
2250        for ch in next_chars {
2251            if Some(kind(ch)) == word_kind && ch != '\n' {
2252                end += ch.len_utf8();
2253            } else {
2254                break;
2255            }
2256        }
2257
2258        (start..end, word_kind)
2259    }
2260
2261    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
2262        if self.singleton {
2263            self.excerpts
2264                .iter()
2265                .next()
2266                .map(|e| (&e.id, e.buffer_id, &e.buffer))
2267        } else {
2268            None
2269        }
2270    }
2271
2272    pub fn len(&self) -> usize {
2273        self.excerpts.summary().text.len
2274    }
2275
2276    pub fn is_empty(&self) -> bool {
2277        self.excerpts.summary().text.len == 0
2278    }
2279
2280    pub fn max_buffer_row(&self) -> MultiBufferRow {
2281        self.excerpts.summary().max_buffer_row
2282    }
2283
2284    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
2285        if let Some((_, _, buffer)) = self.as_singleton() {
2286            return buffer.clip_offset(offset, bias);
2287        }
2288
2289        let mut cursor = self.excerpts.cursor::<usize>();
2290        cursor.seek(&offset, Bias::Right, &());
2291        let overshoot = if let Some(excerpt) = cursor.item() {
2292            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2293            let buffer_offset = excerpt
2294                .buffer
2295                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
2296            buffer_offset.saturating_sub(excerpt_start)
2297        } else {
2298            0
2299        };
2300        cursor.start() + overshoot
2301    }
2302
2303    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
2304        if let Some((_, _, buffer)) = self.as_singleton() {
2305            return buffer.clip_point(point, bias);
2306        }
2307
2308        let mut cursor = self.excerpts.cursor::<Point>();
2309        cursor.seek(&point, Bias::Right, &());
2310        let overshoot = if let Some(excerpt) = cursor.item() {
2311            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2312            let buffer_point = excerpt
2313                .buffer
2314                .clip_point(excerpt_start + (point - cursor.start()), bias);
2315            buffer_point.saturating_sub(excerpt_start)
2316        } else {
2317            Point::zero()
2318        };
2319        *cursor.start() + overshoot
2320    }
2321
2322    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
2323        if let Some((_, _, buffer)) = self.as_singleton() {
2324            return buffer.clip_offset_utf16(offset, bias);
2325        }
2326
2327        let mut cursor = self.excerpts.cursor::<OffsetUtf16>();
2328        cursor.seek(&offset, Bias::Right, &());
2329        let overshoot = if let Some(excerpt) = cursor.item() {
2330            let excerpt_start = excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2331            let buffer_offset = excerpt
2332                .buffer
2333                .clip_offset_utf16(excerpt_start + (offset - cursor.start()), bias);
2334            OffsetUtf16(buffer_offset.0.saturating_sub(excerpt_start.0))
2335        } else {
2336            OffsetUtf16(0)
2337        };
2338        *cursor.start() + overshoot
2339    }
2340
2341    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
2342        if let Some((_, _, buffer)) = self.as_singleton() {
2343            return buffer.clip_point_utf16(point, bias);
2344        }
2345
2346        let mut cursor = self.excerpts.cursor::<PointUtf16>();
2347        cursor.seek(&point.0, Bias::Right, &());
2348        let overshoot = if let Some(excerpt) = cursor.item() {
2349            let excerpt_start = excerpt
2350                .buffer
2351                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2352            let buffer_point = excerpt
2353                .buffer
2354                .clip_point_utf16(Unclipped(excerpt_start + (point.0 - cursor.start())), bias);
2355            buffer_point.saturating_sub(excerpt_start)
2356        } else {
2357            PointUtf16::zero()
2358        };
2359        *cursor.start() + overshoot
2360    }
2361
2362    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
2363        let range = range.start.to_offset(self)..range.end.to_offset(self);
2364        let mut excerpts = self.excerpts.cursor::<usize>();
2365        excerpts.seek(&range.start, Bias::Right, &());
2366
2367        let mut chunk = &[][..];
2368        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2369            let mut excerpt_bytes = excerpt
2370                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
2371            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2372            Some(excerpt_bytes)
2373        } else {
2374            None
2375        };
2376        MultiBufferBytes {
2377            range,
2378            excerpts,
2379            excerpt_bytes,
2380            chunk,
2381        }
2382    }
2383
2384    pub fn reversed_bytes_in_range<T: ToOffset>(
2385        &self,
2386        range: Range<T>,
2387    ) -> ReversedMultiBufferBytes {
2388        let range = range.start.to_offset(self)..range.end.to_offset(self);
2389        let mut excerpts = self.excerpts.cursor::<usize>();
2390        excerpts.seek(&range.end, Bias::Left, &());
2391
2392        let mut chunk = &[][..];
2393        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2394            let mut excerpt_bytes = excerpt.reversed_bytes_in_range(
2395                range.start.saturating_sub(*excerpts.start())..range.end - *excerpts.start(),
2396            );
2397            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2398            Some(excerpt_bytes)
2399        } else {
2400            None
2401        };
2402
2403        ReversedMultiBufferBytes {
2404            range,
2405            excerpts,
2406            excerpt_bytes,
2407            chunk,
2408        }
2409    }
2410
2411    pub fn buffer_rows(&self, start_row: MultiBufferRow) -> MultiBufferRows {
2412        let mut result = MultiBufferRows {
2413            buffer_row_range: 0..0,
2414            excerpts: self.excerpts.cursor(),
2415        };
2416        result.seek(start_row);
2417        result
2418    }
2419
2420    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
2421        let range = range.start.to_offset(self)..range.end.to_offset(self);
2422        let mut chunks = MultiBufferChunks {
2423            range: range.clone(),
2424            excerpts: self.excerpts.cursor(),
2425            excerpt_chunks: None,
2426            language_aware,
2427        };
2428        chunks.seek(range.start);
2429        chunks
2430    }
2431
2432    pub fn offset_to_point(&self, offset: usize) -> Point {
2433        if let Some((_, _, buffer)) = self.as_singleton() {
2434            return buffer.offset_to_point(offset);
2435        }
2436
2437        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2438        cursor.seek(&offset, Bias::Right, &());
2439        if let Some(excerpt) = cursor.item() {
2440            let (start_offset, start_point) = cursor.start();
2441            let overshoot = offset - start_offset;
2442            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2443            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2444            let buffer_point = excerpt
2445                .buffer
2446                .offset_to_point(excerpt_start_offset + overshoot);
2447            *start_point + (buffer_point - excerpt_start_point)
2448        } else {
2449            self.excerpts.summary().text.lines
2450        }
2451    }
2452
2453    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
2454        if let Some((_, _, buffer)) = self.as_singleton() {
2455            return buffer.offset_to_point_utf16(offset);
2456        }
2457
2458        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
2459        cursor.seek(&offset, Bias::Right, &());
2460        if let Some(excerpt) = cursor.item() {
2461            let (start_offset, start_point) = cursor.start();
2462            let overshoot = offset - start_offset;
2463            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2464            let excerpt_start_point = excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2465            let buffer_point = excerpt
2466                .buffer
2467                .offset_to_point_utf16(excerpt_start_offset + overshoot);
2468            *start_point + (buffer_point - excerpt_start_point)
2469        } else {
2470            self.excerpts.summary().text.lines_utf16()
2471        }
2472    }
2473
2474    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
2475        if let Some((_, _, buffer)) = self.as_singleton() {
2476            return buffer.point_to_point_utf16(point);
2477        }
2478
2479        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
2480        cursor.seek(&point, Bias::Right, &());
2481        if let Some(excerpt) = cursor.item() {
2482            let (start_offset, start_point) = cursor.start();
2483            let overshoot = point - start_offset;
2484            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2485            let excerpt_start_point_utf16 =
2486                excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2487            let buffer_point = excerpt
2488                .buffer
2489                .point_to_point_utf16(excerpt_start_point + overshoot);
2490            *start_point + (buffer_point - excerpt_start_point_utf16)
2491        } else {
2492            self.excerpts.summary().text.lines_utf16()
2493        }
2494    }
2495
2496    pub fn point_to_offset(&self, point: Point) -> usize {
2497        if let Some((_, _, buffer)) = self.as_singleton() {
2498            return buffer.point_to_offset(point);
2499        }
2500
2501        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
2502        cursor.seek(&point, Bias::Right, &());
2503        if let Some(excerpt) = cursor.item() {
2504            let (start_point, start_offset) = cursor.start();
2505            let overshoot = point - start_point;
2506            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2507            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2508            let buffer_offset = excerpt
2509                .buffer
2510                .point_to_offset(excerpt_start_point + overshoot);
2511            *start_offset + buffer_offset - excerpt_start_offset
2512        } else {
2513            self.excerpts.summary().text.len
2514        }
2515    }
2516
2517    pub fn offset_utf16_to_offset(&self, offset_utf16: OffsetUtf16) -> usize {
2518        if let Some((_, _, buffer)) = self.as_singleton() {
2519            return buffer.offset_utf16_to_offset(offset_utf16);
2520        }
2521
2522        let mut cursor = self.excerpts.cursor::<(OffsetUtf16, usize)>();
2523        cursor.seek(&offset_utf16, Bias::Right, &());
2524        if let Some(excerpt) = cursor.item() {
2525            let (start_offset_utf16, start_offset) = cursor.start();
2526            let overshoot = offset_utf16 - start_offset_utf16;
2527            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2528            let excerpt_start_offset_utf16 =
2529                excerpt.buffer.offset_to_offset_utf16(excerpt_start_offset);
2530            let buffer_offset = excerpt
2531                .buffer
2532                .offset_utf16_to_offset(excerpt_start_offset_utf16 + overshoot);
2533            *start_offset + (buffer_offset - excerpt_start_offset)
2534        } else {
2535            self.excerpts.summary().text.len
2536        }
2537    }
2538
2539    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
2540        if let Some((_, _, buffer)) = self.as_singleton() {
2541            return buffer.offset_to_offset_utf16(offset);
2542        }
2543
2544        let mut cursor = self.excerpts.cursor::<(usize, OffsetUtf16)>();
2545        cursor.seek(&offset, Bias::Right, &());
2546        if let Some(excerpt) = cursor.item() {
2547            let (start_offset, start_offset_utf16) = cursor.start();
2548            let overshoot = offset - start_offset;
2549            let excerpt_start_offset_utf16 =
2550                excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2551            let excerpt_start_offset = excerpt
2552                .buffer
2553                .offset_utf16_to_offset(excerpt_start_offset_utf16);
2554            let buffer_offset_utf16 = excerpt
2555                .buffer
2556                .offset_to_offset_utf16(excerpt_start_offset + overshoot);
2557            *start_offset_utf16 + (buffer_offset_utf16 - excerpt_start_offset_utf16)
2558        } else {
2559            self.excerpts.summary().text.len_utf16
2560        }
2561    }
2562
2563    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
2564        if let Some((_, _, buffer)) = self.as_singleton() {
2565            return buffer.point_utf16_to_offset(point);
2566        }
2567
2568        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
2569        cursor.seek(&point, Bias::Right, &());
2570        if let Some(excerpt) = cursor.item() {
2571            let (start_point, start_offset) = cursor.start();
2572            let overshoot = point - start_point;
2573            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2574            let excerpt_start_point = excerpt
2575                .buffer
2576                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2577            let buffer_offset = excerpt
2578                .buffer
2579                .point_utf16_to_offset(excerpt_start_point + overshoot);
2580            *start_offset + (buffer_offset - excerpt_start_offset)
2581        } else {
2582            self.excerpts.summary().text.len
2583        }
2584    }
2585
2586    pub fn point_to_buffer_offset<T: ToOffset>(
2587        &self,
2588        point: T,
2589    ) -> Option<(&BufferSnapshot, usize)> {
2590        let offset = point.to_offset(self);
2591        let mut cursor = self.excerpts.cursor::<usize>();
2592        cursor.seek(&offset, Bias::Right, &());
2593        if cursor.item().is_none() {
2594            cursor.prev(&());
2595        }
2596
2597        cursor.item().map(|excerpt| {
2598            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2599            let buffer_point = excerpt_start + offset - *cursor.start();
2600            (&excerpt.buffer, buffer_point)
2601        })
2602    }
2603
2604    pub fn suggested_indents(
2605        &self,
2606        rows: impl IntoIterator<Item = u32>,
2607        cx: &AppContext,
2608    ) -> BTreeMap<MultiBufferRow, IndentSize> {
2609        let mut result = BTreeMap::new();
2610
2611        let mut rows_for_excerpt = Vec::new();
2612        let mut cursor = self.excerpts.cursor::<Point>();
2613        let mut rows = rows.into_iter().peekable();
2614        let mut prev_row = u32::MAX;
2615        let mut prev_language_indent_size = IndentSize::default();
2616
2617        while let Some(row) = rows.next() {
2618            cursor.seek(&Point::new(row, 0), Bias::Right, &());
2619            let excerpt = match cursor.item() {
2620                Some(excerpt) => excerpt,
2621                _ => continue,
2622            };
2623
2624            // Retrieve the language and indent size once for each disjoint region being indented.
2625            let single_indent_size = if row.saturating_sub(1) == prev_row {
2626                prev_language_indent_size
2627            } else {
2628                excerpt
2629                    .buffer
2630                    .language_indent_size_at(Point::new(row, 0), cx)
2631            };
2632            prev_language_indent_size = single_indent_size;
2633            prev_row = row;
2634
2635            let start_buffer_row = excerpt.range.context.start.to_point(&excerpt.buffer).row;
2636            let start_multibuffer_row = cursor.start().row;
2637
2638            rows_for_excerpt.push(row);
2639            while let Some(next_row) = rows.peek().copied() {
2640                if cursor.end(&()).row > next_row {
2641                    rows_for_excerpt.push(next_row);
2642                    rows.next();
2643                } else {
2644                    break;
2645                }
2646            }
2647
2648            let buffer_rows = rows_for_excerpt
2649                .drain(..)
2650                .map(|row| start_buffer_row + row - start_multibuffer_row);
2651            let buffer_indents = excerpt
2652                .buffer
2653                .suggested_indents(buffer_rows, single_indent_size);
2654            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
2655                (
2656                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
2657                    indent,
2658                )
2659            });
2660            result.extend(multibuffer_indents);
2661        }
2662
2663        result
2664    }
2665
2666    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
2667        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
2668            let mut size = buffer.indent_size_for_line(range.start.row);
2669            size.len = size
2670                .len
2671                .min(range.end.column)
2672                .saturating_sub(range.start.column);
2673            size
2674        } else {
2675            IndentSize::spaces(0)
2676        }
2677    }
2678
2679    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
2680        while row.0 > 0 {
2681            row.0 -= 1;
2682            if !self.is_line_blank(row) {
2683                return Some(row);
2684            }
2685        }
2686        None
2687    }
2688
2689    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
2690        if let Some((_, range)) = self.buffer_line_for_row(row) {
2691            range.end.column - range.start.column
2692        } else {
2693            0
2694        }
2695    }
2696
2697    pub fn buffer_line_for_row(
2698        &self,
2699        row: MultiBufferRow,
2700    ) -> Option<(&BufferSnapshot, Range<Point>)> {
2701        let mut cursor = self.excerpts.cursor::<Point>();
2702        let point = Point::new(row.0, 0);
2703        cursor.seek(&point, Bias::Right, &());
2704        if cursor.item().is_none() && *cursor.start() == point {
2705            cursor.prev(&());
2706        }
2707        if let Some(excerpt) = cursor.item() {
2708            let overshoot = row.0 - cursor.start().row;
2709            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2710            let excerpt_end = excerpt.range.context.end.to_point(&excerpt.buffer);
2711            let buffer_row = excerpt_start.row + overshoot;
2712            let line_start = Point::new(buffer_row, 0);
2713            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
2714            return Some((
2715                &excerpt.buffer,
2716                line_start.max(excerpt_start)..line_end.min(excerpt_end),
2717            ));
2718        }
2719        None
2720    }
2721
2722    pub fn max_point(&self) -> Point {
2723        self.text_summary().lines
2724    }
2725
2726    pub fn text_summary(&self) -> TextSummary {
2727        self.excerpts.summary().text.clone()
2728    }
2729
2730    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
2731    where
2732        D: TextDimension,
2733        O: ToOffset,
2734    {
2735        let mut summary = D::default();
2736        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
2737        let mut cursor = self.excerpts.cursor::<usize>();
2738        cursor.seek(&range.start, Bias::Right, &());
2739        if let Some(excerpt) = cursor.item() {
2740            let mut end_before_newline = cursor.end(&());
2741            if excerpt.has_trailing_newline {
2742                end_before_newline -= 1;
2743            }
2744
2745            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2746            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
2747            let end_in_excerpt =
2748                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
2749            summary.add_assign(
2750                &excerpt
2751                    .buffer
2752                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
2753            );
2754
2755            if range.end > end_before_newline {
2756                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
2757            }
2758
2759            cursor.next(&());
2760        }
2761
2762        if range.end > *cursor.start() {
2763            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
2764                &range.end,
2765                Bias::Right,
2766                &(),
2767            )));
2768            if let Some(excerpt) = cursor.item() {
2769                range.end = cmp::max(*cursor.start(), range.end);
2770
2771                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2772                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
2773                summary.add_assign(
2774                    &excerpt
2775                        .buffer
2776                        .text_summary_for_range(excerpt_start..end_in_excerpt),
2777                );
2778            }
2779        }
2780
2781        summary
2782    }
2783
2784    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
2785    where
2786        D: TextDimension + Ord + Sub<D, Output = D>,
2787    {
2788        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2789        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
2790
2791        cursor.seek(locator, Bias::Left, &());
2792        if cursor.item().is_none() {
2793            cursor.next(&());
2794        }
2795
2796        let mut position = D::from_text_summary(&cursor.start().text);
2797        if let Some(excerpt) = cursor.item() {
2798            if excerpt.id == anchor.excerpt_id {
2799                let excerpt_buffer_start =
2800                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2801                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2802                let buffer_position = cmp::min(
2803                    excerpt_buffer_end,
2804                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
2805                );
2806                if buffer_position > excerpt_buffer_start {
2807                    position.add_assign(&(buffer_position - excerpt_buffer_start));
2808                }
2809            }
2810        }
2811        position
2812    }
2813
2814    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
2815    where
2816        D: TextDimension + Ord + Sub<D, Output = D>,
2817        I: 'a + IntoIterator<Item = &'a Anchor>,
2818    {
2819        if let Some((_, _, buffer)) = self.as_singleton() {
2820            return buffer
2821                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
2822                .collect();
2823        }
2824
2825        let mut anchors = anchors.into_iter().peekable();
2826        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2827        let mut summaries = Vec::new();
2828        while let Some(anchor) = anchors.peek() {
2829            let excerpt_id = anchor.excerpt_id;
2830            let excerpt_anchors = iter::from_fn(|| {
2831                let anchor = anchors.peek()?;
2832                if anchor.excerpt_id == excerpt_id {
2833                    Some(&anchors.next().unwrap().text_anchor)
2834                } else {
2835                    None
2836                }
2837            });
2838
2839            let locator = self.excerpt_locator_for_id(excerpt_id);
2840            cursor.seek_forward(locator, Bias::Left, &());
2841            if cursor.item().is_none() {
2842                cursor.next(&());
2843            }
2844
2845            let position = D::from_text_summary(&cursor.start().text);
2846            if let Some(excerpt) = cursor.item() {
2847                if excerpt.id == excerpt_id {
2848                    let excerpt_buffer_start =
2849                        excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2850                    let excerpt_buffer_end =
2851                        excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2852                    summaries.extend(
2853                        excerpt
2854                            .buffer
2855                            .summaries_for_anchors::<D, _>(excerpt_anchors)
2856                            .map(move |summary| {
2857                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
2858                                let mut position = position.clone();
2859                                let excerpt_buffer_start = excerpt_buffer_start.clone();
2860                                if summary > excerpt_buffer_start {
2861                                    position.add_assign(&(summary - excerpt_buffer_start));
2862                                }
2863                                position
2864                            }),
2865                    );
2866                    continue;
2867                }
2868            }
2869
2870            summaries.extend(excerpt_anchors.map(|_| position.clone()));
2871        }
2872
2873        summaries
2874    }
2875
2876    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
2877    where
2878        I: 'a + IntoIterator<Item = &'a Anchor>,
2879    {
2880        let mut anchors = anchors.into_iter().enumerate().peekable();
2881        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
2882        cursor.next(&());
2883
2884        let mut result = Vec::new();
2885
2886        while let Some((_, anchor)) = anchors.peek() {
2887            let old_excerpt_id = anchor.excerpt_id;
2888
2889            // Find the location where this anchor's excerpt should be.
2890            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
2891            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
2892
2893            if cursor.item().is_none() {
2894                cursor.next(&());
2895            }
2896
2897            let next_excerpt = cursor.item();
2898            let prev_excerpt = cursor.prev_item();
2899
2900            // Process all of the anchors for this excerpt.
2901            while let Some((_, anchor)) = anchors.peek() {
2902                if anchor.excerpt_id != old_excerpt_id {
2903                    break;
2904                }
2905                let (anchor_ix, anchor) = anchors.next().unwrap();
2906                let mut anchor = *anchor;
2907
2908                // Leave min and max anchors unchanged if invalid or
2909                // if the old excerpt still exists at this location
2910                let mut kept_position = next_excerpt
2911                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
2912                    || old_excerpt_id == ExcerptId::max()
2913                    || old_excerpt_id == ExcerptId::min();
2914
2915                // If the old excerpt no longer exists at this location, then attempt to
2916                // find an equivalent position for this anchor in an adjacent excerpt.
2917                if !kept_position {
2918                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
2919                        if excerpt.contains(&anchor) {
2920                            anchor.excerpt_id = excerpt.id;
2921                            kept_position = true;
2922                            break;
2923                        }
2924                    }
2925                }
2926
2927                // If there's no adjacent excerpt that contains the anchor's position,
2928                // then report that the anchor has lost its position.
2929                if !kept_position {
2930                    anchor = if let Some(excerpt) = next_excerpt {
2931                        let mut text_anchor = excerpt
2932                            .range
2933                            .context
2934                            .start
2935                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2936                        if text_anchor
2937                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
2938                            .is_gt()
2939                        {
2940                            text_anchor = excerpt.range.context.end;
2941                        }
2942                        Anchor {
2943                            buffer_id: Some(excerpt.buffer_id),
2944                            excerpt_id: excerpt.id,
2945                            text_anchor,
2946                        }
2947                    } else if let Some(excerpt) = prev_excerpt {
2948                        let mut text_anchor = excerpt
2949                            .range
2950                            .context
2951                            .end
2952                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2953                        if text_anchor
2954                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
2955                            .is_lt()
2956                        {
2957                            text_anchor = excerpt.range.context.start;
2958                        }
2959                        Anchor {
2960                            buffer_id: Some(excerpt.buffer_id),
2961                            excerpt_id: excerpt.id,
2962                            text_anchor,
2963                        }
2964                    } else if anchor.text_anchor.bias == Bias::Left {
2965                        Anchor::min()
2966                    } else {
2967                        Anchor::max()
2968                    };
2969                }
2970
2971                result.push((anchor_ix, anchor, kept_position));
2972            }
2973        }
2974        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
2975        result
2976    }
2977
2978    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
2979        self.anchor_at(position, Bias::Left)
2980    }
2981
2982    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
2983        self.anchor_at(position, Bias::Right)
2984    }
2985
2986    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
2987        let offset = position.to_offset(self);
2988        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
2989            return Anchor {
2990                buffer_id: Some(buffer_id),
2991                excerpt_id: *excerpt_id,
2992                text_anchor: buffer.anchor_at(offset, bias),
2993            };
2994        }
2995
2996        let mut cursor = self.excerpts.cursor::<(usize, Option<ExcerptId>)>();
2997        cursor.seek(&offset, Bias::Right, &());
2998        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
2999            cursor.prev(&());
3000        }
3001        if let Some(excerpt) = cursor.item() {
3002            let mut overshoot = offset.saturating_sub(cursor.start().0);
3003            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
3004                overshoot -= 1;
3005                bias = Bias::Right;
3006            }
3007
3008            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
3009            let text_anchor =
3010                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
3011            Anchor {
3012                buffer_id: Some(excerpt.buffer_id),
3013                excerpt_id: excerpt.id,
3014                text_anchor,
3015            }
3016        } else if offset == 0 && bias == Bias::Left {
3017            Anchor::min()
3018        } else {
3019            Anchor::max()
3020        }
3021    }
3022
3023    /// Returns an anchor for the given excerpt and text anchor,
3024    /// returns None if the excerpt_id is no longer valid.
3025    pub fn anchor_in_excerpt(
3026        &self,
3027        excerpt_id: ExcerptId,
3028        text_anchor: text::Anchor,
3029    ) -> Option<Anchor> {
3030        let locator = self.excerpt_locator_for_id(excerpt_id);
3031        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
3032        cursor.seek(locator, Bias::Left, &());
3033        if let Some(excerpt) = cursor.item() {
3034            if excerpt.id == excerpt_id {
3035                let text_anchor = excerpt.clip_anchor(text_anchor);
3036                drop(cursor);
3037                return Some(Anchor {
3038                    buffer_id: Some(excerpt.buffer_id),
3039                    excerpt_id,
3040                    text_anchor,
3041                });
3042            }
3043        }
3044        None
3045    }
3046
3047    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
3048        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
3049            true
3050        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
3051            excerpt.buffer.can_resolve(&anchor.text_anchor)
3052        } else {
3053            false
3054        }
3055    }
3056
3057    pub fn excerpts(
3058        &self,
3059    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
3060        self.excerpts
3061            .iter()
3062            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
3063    }
3064
3065    fn excerpts_for_range<T: ToOffset>(
3066        &self,
3067        range: Range<T>,
3068    ) -> impl Iterator<Item = (&Excerpt, usize)> + '_ {
3069        let range = range.start.to_offset(self)..range.end.to_offset(self);
3070
3071        let mut cursor = self.excerpts.cursor::<usize>();
3072        cursor.seek(&range.start, Bias::Right, &());
3073        cursor.prev(&());
3074
3075        iter::from_fn(move || {
3076            cursor.next(&());
3077            if cursor.start() < &range.end {
3078                cursor.item().map(|item| (item, *cursor.start()))
3079            } else {
3080                None
3081            }
3082        })
3083    }
3084
3085    pub fn excerpt_boundaries_in_range<R, T>(
3086        &self,
3087        range: R,
3088    ) -> impl Iterator<Item = ExcerptBoundary> + '_
3089    where
3090        R: RangeBounds<T>,
3091        T: ToOffset,
3092    {
3093        let start_offset;
3094        let start = match range.start_bound() {
3095            Bound::Included(start) => {
3096                start_offset = start.to_offset(self);
3097                Bound::Included(start_offset)
3098            }
3099            Bound::Excluded(start) => {
3100                start_offset = start.to_offset(self);
3101                Bound::Excluded(start_offset)
3102            }
3103            Bound::Unbounded => {
3104                start_offset = 0;
3105                Bound::Unbounded
3106            }
3107        };
3108        let end = match range.end_bound() {
3109            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3110            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3111            Bound::Unbounded => Bound::Unbounded,
3112        };
3113        let bounds = (start, end);
3114
3115        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
3116        cursor.seek(&start_offset, Bias::Right, &());
3117        if cursor.item().is_none() {
3118            cursor.prev(&());
3119        }
3120        if !bounds.contains(&cursor.start().0) {
3121            cursor.next(&());
3122        }
3123
3124        let mut visited_end = false;
3125        std::iter::from_fn(move || {
3126            if self.singleton {
3127                None
3128            } else if bounds.contains(&cursor.start().0) {
3129                let next = cursor.item().map(|excerpt| ExcerptInfo {
3130                    id: excerpt.id,
3131                    buffer: excerpt.buffer.clone(),
3132                    buffer_id: excerpt.buffer_id,
3133                    range: excerpt.range.clone(),
3134                });
3135
3136                if next.is_none() {
3137                    if visited_end {
3138                        return None;
3139                    } else {
3140                        visited_end = true;
3141                    }
3142                }
3143
3144                let prev = cursor.prev_item().map(|prev_excerpt| ExcerptInfo {
3145                    id: prev_excerpt.id,
3146                    buffer: prev_excerpt.buffer.clone(),
3147                    buffer_id: prev_excerpt.buffer_id,
3148                    range: prev_excerpt.range.clone(),
3149                });
3150                let row = MultiBufferRow(cursor.start().1.row);
3151
3152                cursor.next(&());
3153
3154                Some(ExcerptBoundary { row, prev, next })
3155            } else {
3156                None
3157            }
3158        })
3159    }
3160
3161    pub fn edit_count(&self) -> usize {
3162        self.edit_count
3163    }
3164
3165    pub fn non_text_state_update_count(&self) -> usize {
3166        self.non_text_state_update_count
3167    }
3168
3169    /// Returns the smallest enclosing bracket ranges containing the given range or
3170    /// None if no brackets contain range or the range is not contained in a single
3171    /// excerpt
3172    ///
3173    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
3174    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
3175        &self,
3176        range: Range<T>,
3177        range_filter: Option<&dyn Fn(Range<usize>, Range<usize>) -> bool>,
3178    ) -> Option<(Range<usize>, Range<usize>)> {
3179        let range = range.start.to_offset(self)..range.end.to_offset(self);
3180        let excerpt = self.excerpt_containing(range.clone())?;
3181
3182        // Filter to ranges contained in the excerpt
3183        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
3184            excerpt.contains_buffer_range(open.start..close.end)
3185                && range_filter.map_or(true, |filter| {
3186                    filter(
3187                        excerpt.map_range_from_buffer(open),
3188                        excerpt.map_range_from_buffer(close),
3189                    )
3190                })
3191        };
3192
3193        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
3194            excerpt.map_range_to_buffer(range),
3195            Some(&range_filter),
3196        )?;
3197
3198        Some((
3199            excerpt.map_range_from_buffer(open),
3200            excerpt.map_range_from_buffer(close),
3201        ))
3202    }
3203
3204    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
3205    /// not contained in a single excerpt
3206    pub fn enclosing_bracket_ranges<T: ToOffset>(
3207        &self,
3208        range: Range<T>,
3209    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
3210        let range = range.start.to_offset(self)..range.end.to_offset(self);
3211        let excerpt = self.excerpt_containing(range.clone())?;
3212
3213        Some(
3214            excerpt
3215                .buffer()
3216                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
3217                .filter_map(move |(open, close)| {
3218                    if excerpt.contains_buffer_range(open.start..close.end) {
3219                        Some((
3220                            excerpt.map_range_from_buffer(open),
3221                            excerpt.map_range_from_buffer(close),
3222                        ))
3223                    } else {
3224                        None
3225                    }
3226                }),
3227        )
3228    }
3229
3230    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
3231    /// not contained in a single excerpt
3232    pub fn bracket_ranges<T: ToOffset>(
3233        &self,
3234        range: Range<T>,
3235    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
3236        let range = range.start.to_offset(self)..range.end.to_offset(self);
3237        let excerpt = self.excerpt_containing(range.clone())?;
3238
3239        Some(
3240            excerpt
3241                .buffer()
3242                .bracket_ranges(excerpt.map_range_to_buffer(range))
3243                .filter_map(move |(start_bracket_range, close_bracket_range)| {
3244                    let buffer_range = start_bracket_range.start..close_bracket_range.end;
3245                    if excerpt.contains_buffer_range(buffer_range) {
3246                        Some((
3247                            excerpt.map_range_from_buffer(start_bracket_range),
3248                            excerpt.map_range_from_buffer(close_bracket_range),
3249                        ))
3250                    } else {
3251                        None
3252                    }
3253                }),
3254        )
3255    }
3256
3257    pub fn redacted_ranges<'a, T: ToOffset>(
3258        &'a self,
3259        range: Range<T>,
3260        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
3261    ) -> impl Iterator<Item = Range<usize>> + 'a {
3262        let range = range.start.to_offset(self)..range.end.to_offset(self);
3263        self.excerpts_for_range(range.clone())
3264            .filter_map(move |(excerpt, excerpt_offset)| {
3265                redaction_enabled(excerpt.buffer.file()).then(move || {
3266                    let excerpt_buffer_start =
3267                        excerpt.range.context.start.to_offset(&excerpt.buffer);
3268
3269                    excerpt
3270                        .buffer
3271                        .redacted_ranges(excerpt.range.context.clone())
3272                        .map(move |mut redacted_range| {
3273                            // Re-base onto the excerpts coordinates in the multibuffer
3274                            redacted_range.start = excerpt_offset
3275                                + redacted_range.start.saturating_sub(excerpt_buffer_start);
3276                            redacted_range.end = excerpt_offset
3277                                + redacted_range.end.saturating_sub(excerpt_buffer_start);
3278
3279                            redacted_range
3280                        })
3281                        .skip_while(move |redacted_range| redacted_range.end < range.start)
3282                        .take_while(move |redacted_range| redacted_range.start < range.end)
3283                })
3284            })
3285            .flatten()
3286    }
3287
3288    pub fn runnable_ranges(
3289        &self,
3290        range: Range<Anchor>,
3291    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
3292        let range = range.start.to_offset(self)..range.end.to_offset(self);
3293        self.excerpts_for_range(range.clone())
3294            .flat_map(move |(excerpt, excerpt_offset)| {
3295                let excerpt_buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
3296
3297                excerpt
3298                    .buffer
3299                    .runnable_ranges(excerpt.range.context.clone())
3300                    .filter_map(move |mut runnable| {
3301                        // Re-base onto the excerpts coordinates in the multibuffer
3302                        //
3303                        // The node matching our runnables query might partially overlap with
3304                        // the provided range. If the run indicator is outside of excerpt bounds, do not actually show it.
3305                        if runnable.run_range.start < excerpt_buffer_start {
3306                            return None;
3307                        }
3308                        if language::ToPoint::to_point(&runnable.run_range.end, &excerpt.buffer).row
3309                            > excerpt.max_buffer_row
3310                        {
3311                            return None;
3312                        }
3313                        runnable.run_range.start =
3314                            excerpt_offset + runnable.run_range.start - excerpt_buffer_start;
3315                        runnable.run_range.end =
3316                            excerpt_offset + runnable.run_range.end - excerpt_buffer_start;
3317                        Some(runnable)
3318                    })
3319                    .skip_while(move |runnable| runnable.run_range.end < range.start)
3320                    .take_while(move |runnable| runnable.run_range.start < range.end)
3321            })
3322    }
3323
3324    pub fn indent_guides_in_range(
3325        &self,
3326        range: Range<Anchor>,
3327        ignore_disabled_for_language: bool,
3328        cx: &AppContext,
3329    ) -> Vec<MultiBufferIndentGuide> {
3330        // Fast path for singleton buffers, we can skip the conversion between offsets.
3331        if let Some((_, _, snapshot)) = self.as_singleton() {
3332            return snapshot
3333                .indent_guides_in_range(
3334                    range.start.text_anchor..range.end.text_anchor,
3335                    ignore_disabled_for_language,
3336                    cx,
3337                )
3338                .into_iter()
3339                .map(|guide| MultiBufferIndentGuide {
3340                    multibuffer_row_range: MultiBufferRow(guide.start_row)
3341                        ..MultiBufferRow(guide.end_row),
3342                    buffer: guide,
3343                })
3344                .collect();
3345        }
3346
3347        let range = range.start.to_offset(self)..range.end.to_offset(self);
3348
3349        self.excerpts_for_range(range.clone())
3350            .flat_map(move |(excerpt, excerpt_offset)| {
3351                let excerpt_buffer_start_row =
3352                    excerpt.range.context.start.to_point(&excerpt.buffer).row;
3353                let excerpt_offset_row = crate::ToPoint::to_point(&excerpt_offset, self).row;
3354
3355                excerpt
3356                    .buffer
3357                    .indent_guides_in_range(
3358                        excerpt.range.context.clone(),
3359                        ignore_disabled_for_language,
3360                        cx,
3361                    )
3362                    .into_iter()
3363                    .map(move |indent_guide| {
3364                        let start_row = excerpt_offset_row
3365                            + (indent_guide.start_row - excerpt_buffer_start_row);
3366                        let end_row =
3367                            excerpt_offset_row + (indent_guide.end_row - excerpt_buffer_start_row);
3368
3369                        MultiBufferIndentGuide {
3370                            multibuffer_row_range: MultiBufferRow(start_row)
3371                                ..MultiBufferRow(end_row),
3372                            buffer: indent_guide,
3373                        }
3374                    })
3375            })
3376            .collect()
3377    }
3378
3379    pub fn trailing_excerpt_update_count(&self) -> usize {
3380        self.trailing_excerpt_update_count
3381    }
3382
3383    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
3384        self.point_to_buffer_offset(point)
3385            .and_then(|(buffer, _)| buffer.file())
3386    }
3387
3388    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
3389        self.point_to_buffer_offset(point)
3390            .and_then(|(buffer, offset)| buffer.language_at(offset))
3391    }
3392
3393    pub fn settings_at<'a, T: ToOffset>(
3394        &'a self,
3395        point: T,
3396        cx: &'a AppContext,
3397    ) -> &'a LanguageSettings {
3398        let mut language = None;
3399        let mut file = None;
3400        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
3401            language = buffer.language_at(offset);
3402            file = buffer.file();
3403        }
3404        language_settings(language, file, cx)
3405    }
3406
3407    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
3408        self.point_to_buffer_offset(point)
3409            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
3410    }
3411
3412    pub fn language_indent_size_at<T: ToOffset>(
3413        &self,
3414        position: T,
3415        cx: &AppContext,
3416    ) -> Option<IndentSize> {
3417        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
3418        Some(buffer_snapshot.language_indent_size_at(offset, cx))
3419    }
3420
3421    pub fn is_dirty(&self) -> bool {
3422        self.is_dirty
3423    }
3424
3425    pub fn has_conflict(&self) -> bool {
3426        self.has_conflict
3427    }
3428
3429    pub fn has_diagnostics(&self) -> bool {
3430        self.excerpts
3431            .iter()
3432            .any(|excerpt| excerpt.buffer.has_diagnostics())
3433    }
3434
3435    pub fn diagnostic_group<'a, O>(
3436        &'a self,
3437        group_id: usize,
3438    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3439    where
3440        O: text::FromAnchor + 'a,
3441    {
3442        self.as_singleton()
3443            .into_iter()
3444            .flat_map(move |(_, _, buffer)| buffer.diagnostic_group(group_id))
3445    }
3446
3447    pub fn diagnostics_in_range<'a, T, O>(
3448        &'a self,
3449        range: Range<T>,
3450        reversed: bool,
3451    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3452    where
3453        T: 'a + ToOffset,
3454        O: 'a + text::FromAnchor + Ord,
3455    {
3456        self.as_singleton()
3457            .into_iter()
3458            .flat_map(move |(_, _, buffer)| {
3459                buffer.diagnostics_in_range(
3460                    range.start.to_offset(self)..range.end.to_offset(self),
3461                    reversed,
3462                )
3463            })
3464    }
3465
3466    pub fn has_git_diffs(&self) -> bool {
3467        for excerpt in self.excerpts.iter() {
3468            if excerpt.buffer.has_git_diff() {
3469                return true;
3470            }
3471        }
3472        false
3473    }
3474
3475    pub fn git_diff_hunks_in_range_rev(
3476        &self,
3477        row_range: Range<MultiBufferRow>,
3478    ) -> impl Iterator<Item = DiffHunk<MultiBufferRow>> + '_ {
3479        let mut cursor = self.excerpts.cursor::<Point>();
3480
3481        cursor.seek(&Point::new(row_range.end.0, 0), Bias::Left, &());
3482        if cursor.item().is_none() {
3483            cursor.prev(&());
3484        }
3485
3486        std::iter::from_fn(move || {
3487            let excerpt = cursor.item()?;
3488            let multibuffer_start = *cursor.start();
3489            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3490            if multibuffer_start.row >= row_range.end.0 {
3491                return None;
3492            }
3493
3494            let mut buffer_start = excerpt.range.context.start;
3495            let mut buffer_end = excerpt.range.context.end;
3496            let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3497            let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3498
3499            if row_range.start.0 > multibuffer_start.row {
3500                let buffer_start_point =
3501                    excerpt_start_point + Point::new(row_range.start.0 - multibuffer_start.row, 0);
3502                buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3503            }
3504
3505            if row_range.end.0 < multibuffer_end.row {
3506                let buffer_end_point =
3507                    excerpt_start_point + Point::new(row_range.end.0 - multibuffer_start.row, 0);
3508                buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3509            }
3510
3511            let buffer_hunks = excerpt
3512                .buffer
3513                .git_diff_hunks_intersecting_range_rev(buffer_start..buffer_end)
3514                .map(move |hunk| {
3515                    let start = multibuffer_start.row
3516                        + hunk
3517                            .associated_range
3518                            .start
3519                            .saturating_sub(excerpt_start_point.row);
3520                    let end = multibuffer_start.row
3521                        + hunk
3522                            .associated_range
3523                            .end
3524                            .min(excerpt_end_point.row + 1)
3525                            .saturating_sub(excerpt_start_point.row);
3526
3527                    DiffHunk {
3528                        associated_range: MultiBufferRow(start)..MultiBufferRow(end),
3529                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3530                        buffer_range: hunk.buffer_range.clone(),
3531                        buffer_id: hunk.buffer_id,
3532                    }
3533                });
3534
3535            cursor.prev(&());
3536
3537            Some(buffer_hunks)
3538        })
3539        .flatten()
3540    }
3541
3542    pub fn git_diff_hunks_in_range(
3543        &self,
3544        row_range: Range<MultiBufferRow>,
3545    ) -> impl Iterator<Item = DiffHunk<MultiBufferRow>> + '_ {
3546        let mut cursor = self.excerpts.cursor::<Point>();
3547
3548        cursor.seek(&Point::new(row_range.start.0, 0), Bias::Left, &());
3549
3550        std::iter::from_fn(move || {
3551            let excerpt = cursor.item()?;
3552            let multibuffer_start = *cursor.start();
3553            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3554            let mut buffer_start = excerpt.range.context.start;
3555            let mut buffer_end = excerpt.range.context.end;
3556
3557            let excerpt_rows = match multibuffer_start.row.cmp(&row_range.end.0) {
3558                cmp::Ordering::Less => {
3559                    let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3560                    let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3561
3562                    if row_range.start.0 > multibuffer_start.row {
3563                        let buffer_start_point = excerpt_start_point
3564                            + Point::new(row_range.start.0 - multibuffer_start.row, 0);
3565                        buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3566                    }
3567
3568                    if row_range.end.0 < multibuffer_end.row {
3569                        let buffer_end_point = excerpt_start_point
3570                            + Point::new(row_range.end.0 - multibuffer_start.row, 0);
3571                        buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3572                    }
3573                    excerpt_start_point.row..excerpt_end_point.row
3574                }
3575                cmp::Ordering::Equal if row_range.end.0 == 0 => {
3576                    buffer_end = buffer_start;
3577                    0..0
3578                }
3579                cmp::Ordering::Greater | cmp::Ordering::Equal => return None,
3580            };
3581
3582            let buffer_hunks = excerpt
3583                .buffer
3584                .git_diff_hunks_intersecting_range(buffer_start..buffer_end)
3585                .map(move |hunk| {
3586                    let buffer_range = if excerpt_rows.start == 0 && excerpt_rows.end == 0 {
3587                        MultiBufferRow(0)..MultiBufferRow(1)
3588                    } else {
3589                        let start = multibuffer_start.row
3590                            + hunk
3591                                .associated_range
3592                                .start
3593                                .saturating_sub(excerpt_rows.start);
3594                        let end = multibuffer_start.row
3595                            + hunk
3596                                .associated_range
3597                                .end
3598                                .min(excerpt_rows.end + 1)
3599                                .saturating_sub(excerpt_rows.start);
3600                        MultiBufferRow(start)..MultiBufferRow(end)
3601                    };
3602                    DiffHunk {
3603                        associated_range: buffer_range,
3604                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3605                        buffer_range: hunk.buffer_range.clone(),
3606                        buffer_id: hunk.buffer_id,
3607                    }
3608                });
3609
3610            cursor.next(&());
3611
3612            Some(buffer_hunks)
3613        })
3614        .flatten()
3615    }
3616
3617    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
3618        let range = range.start.to_offset(self)..range.end.to_offset(self);
3619        let excerpt = self.excerpt_containing(range.clone())?;
3620
3621        let ancestor_buffer_range = excerpt
3622            .buffer()
3623            .range_for_syntax_ancestor(excerpt.map_range_to_buffer(range))?;
3624
3625        Some(excerpt.map_range_from_buffer(ancestor_buffer_range))
3626    }
3627
3628    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
3629        let (excerpt_id, _, buffer) = self.as_singleton()?;
3630        let outline = buffer.outline(theme)?;
3631        Some(Outline::new(
3632            outline
3633                .items
3634                .into_iter()
3635                .flat_map(|item| {
3636                    Some(OutlineItem {
3637                        depth: item.depth,
3638                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
3639                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
3640                        text: item.text,
3641                        highlight_ranges: item.highlight_ranges,
3642                        name_ranges: item.name_ranges,
3643                        body_range: item.body_range.and_then(|body_range| {
3644                            Some(
3645                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
3646                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
3647                            )
3648                        }),
3649                    })
3650                })
3651                .collect(),
3652        ))
3653    }
3654
3655    pub fn symbols_containing<T: ToOffset>(
3656        &self,
3657        offset: T,
3658        theme: Option<&SyntaxTheme>,
3659    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
3660        let anchor = self.anchor_before(offset);
3661        let excerpt_id = anchor.excerpt_id;
3662        let excerpt = self.excerpt(excerpt_id)?;
3663        Some((
3664            excerpt.buffer_id,
3665            excerpt
3666                .buffer
3667                .symbols_containing(anchor.text_anchor, theme)
3668                .into_iter()
3669                .flatten()
3670                .flat_map(|item| {
3671                    Some(OutlineItem {
3672                        depth: item.depth,
3673                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
3674                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
3675                        text: item.text,
3676                        highlight_ranges: item.highlight_ranges,
3677                        name_ranges: item.name_ranges,
3678                        body_range: item.body_range.and_then(|body_range| {
3679                            Some(
3680                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
3681                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
3682                            )
3683                        }),
3684                    })
3685                })
3686                .collect(),
3687        ))
3688    }
3689
3690    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
3691        if id == ExcerptId::min() {
3692            Locator::min_ref()
3693        } else if id == ExcerptId::max() {
3694            Locator::max_ref()
3695        } else {
3696            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3697            cursor.seek(&id, Bias::Left, &());
3698            if let Some(entry) = cursor.item() {
3699                if entry.id == id {
3700                    return &entry.locator;
3701                }
3702            }
3703            panic!("invalid excerpt id {:?}", id)
3704        }
3705    }
3706
3707    // Returns the locators referenced by the given excerpt ids, sorted by locator.
3708    fn excerpt_locators_for_ids(
3709        &self,
3710        ids: impl IntoIterator<Item = ExcerptId>,
3711    ) -> SmallVec<[Locator; 1]> {
3712        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
3713        sorted_ids.sort_unstable();
3714        let mut locators = SmallVec::new();
3715
3716        while sorted_ids.last() == Some(&ExcerptId::max()) {
3717            sorted_ids.pop();
3718            locators.push(Locator::max());
3719        }
3720
3721        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
3722        if sorted_ids.peek() == Some(&ExcerptId::min()) {
3723            sorted_ids.next();
3724            locators.push(Locator::min());
3725        }
3726
3727        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3728        for id in sorted_ids {
3729            if cursor.seek_forward(&id, Bias::Left, &()) {
3730                locators.push(cursor.item().unwrap().locator.clone());
3731            } else {
3732                panic!("invalid excerpt id {:?}", id);
3733            }
3734        }
3735
3736        locators.sort_unstable();
3737        locators
3738    }
3739
3740    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
3741        Some(self.excerpt(excerpt_id)?.buffer_id)
3742    }
3743
3744    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
3745        Some(&self.excerpt(excerpt_id)?.buffer)
3746    }
3747
3748    pub fn range_for_excerpt<'a, T: sum_tree::Dimension<'a, ExcerptSummary>>(
3749        &'a self,
3750        excerpt_id: ExcerptId,
3751    ) -> Option<Range<T>> {
3752        let mut cursor = self.excerpts.cursor::<(Option<&Locator>, T)>();
3753        let locator = self.excerpt_locator_for_id(excerpt_id);
3754        if cursor.seek(&Some(locator), Bias::Left, &()) {
3755            let start = cursor.start().1.clone();
3756            let end = cursor.end(&()).1;
3757            Some(start..end)
3758        } else {
3759            None
3760        }
3761    }
3762
3763    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
3764        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
3765        let locator = self.excerpt_locator_for_id(excerpt_id);
3766        cursor.seek(&Some(locator), Bias::Left, &());
3767        if let Some(excerpt) = cursor.item() {
3768            if excerpt.id == excerpt_id {
3769                return Some(excerpt);
3770            }
3771        }
3772        None
3773    }
3774
3775    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
3776    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
3777        let range = range.start.to_offset(self)..range.end.to_offset(self);
3778
3779        let mut cursor = self.excerpts.cursor::<usize>();
3780        cursor.seek(&range.start, Bias::Right, &());
3781        let start_excerpt = cursor.item()?;
3782
3783        if range.start == range.end {
3784            return Some(MultiBufferExcerpt::new(start_excerpt, *cursor.start()));
3785        }
3786
3787        cursor.seek(&range.end, Bias::Right, &());
3788        let end_excerpt = cursor.item()?;
3789
3790        if start_excerpt.id == end_excerpt.id {
3791            Some(MultiBufferExcerpt::new(start_excerpt, *cursor.start()))
3792        } else {
3793            None
3794        }
3795    }
3796
3797    /// Returns excerpts overlapping the given ranges. If range spans multiple excerpts returns one range for each excerpt
3798    pub fn excerpts_in_ranges(
3799        &self,
3800        ranges: impl IntoIterator<Item = Range<Anchor>>,
3801    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, Range<usize>)> {
3802        let mut ranges = ranges.into_iter().map(|range| range.to_offset(self));
3803        let mut cursor = self.excerpts.cursor::<usize>();
3804        cursor.next(&());
3805        let mut current_range = ranges.next();
3806        iter::from_fn(move || {
3807            let range = current_range.clone()?;
3808            if range.start >= cursor.end(&()) {
3809                cursor.seek_forward(&range.start, Bias::Right, &());
3810                if range.start == self.len() {
3811                    cursor.prev(&());
3812                }
3813            }
3814
3815            let excerpt = cursor.item()?;
3816            let range_start_in_excerpt = cmp::max(range.start, *cursor.start());
3817            let range_end_in_excerpt = if excerpt.has_trailing_newline {
3818                cmp::min(range.end, cursor.end(&()) - 1)
3819            } else {
3820                cmp::min(range.end, cursor.end(&()))
3821            };
3822            let buffer_range = MultiBufferExcerpt::new(excerpt, *cursor.start())
3823                .map_range_to_buffer(range_start_in_excerpt..range_end_in_excerpt);
3824
3825            if range.end > cursor.end(&()) {
3826                cursor.next(&());
3827            } else {
3828                current_range = ranges.next();
3829            }
3830
3831            Some((excerpt.id, &excerpt.buffer, buffer_range))
3832        })
3833    }
3834
3835    pub fn selections_in_range<'a>(
3836        &'a self,
3837        range: &'a Range<Anchor>,
3838        include_local: bool,
3839    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
3840        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
3841        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
3842        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
3843        cursor.seek(start_locator, Bias::Left, &());
3844        cursor
3845            .take_while(move |excerpt| excerpt.locator <= *end_locator)
3846            .flat_map(move |excerpt| {
3847                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
3848                if excerpt.id == range.start.excerpt_id {
3849                    query_range.start = range.start.text_anchor;
3850                }
3851                if excerpt.id == range.end.excerpt_id {
3852                    query_range.end = range.end.text_anchor;
3853                }
3854
3855                excerpt
3856                    .buffer
3857                    .selections_in_range(query_range, include_local)
3858                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
3859                        selections.map(move |selection| {
3860                            let mut start = Anchor {
3861                                buffer_id: Some(excerpt.buffer_id),
3862                                excerpt_id: excerpt.id,
3863                                text_anchor: selection.start,
3864                            };
3865                            let mut end = Anchor {
3866                                buffer_id: Some(excerpt.buffer_id),
3867                                excerpt_id: excerpt.id,
3868                                text_anchor: selection.end,
3869                            };
3870                            if range.start.cmp(&start, self).is_gt() {
3871                                start = range.start;
3872                            }
3873                            if range.end.cmp(&end, self).is_lt() {
3874                                end = range.end;
3875                            }
3876
3877                            (
3878                                replica_id,
3879                                line_mode,
3880                                cursor_shape,
3881                                Selection {
3882                                    id: selection.id,
3883                                    start,
3884                                    end,
3885                                    reversed: selection.reversed,
3886                                    goal: selection.goal,
3887                                },
3888                            )
3889                        })
3890                    })
3891            })
3892    }
3893
3894    pub fn show_headers(&self) -> bool {
3895        self.show_headers
3896    }
3897}
3898
3899#[cfg(any(test, feature = "test-support"))]
3900impl MultiBufferSnapshot {
3901    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
3902        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
3903        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
3904        start..end
3905    }
3906}
3907
3908impl History {
3909    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
3910        self.transaction_depth += 1;
3911        if self.transaction_depth == 1 {
3912            let id = self.next_transaction_id.tick();
3913            self.undo_stack.push(Transaction {
3914                id,
3915                buffer_transactions: Default::default(),
3916                first_edit_at: now,
3917                last_edit_at: now,
3918                suppress_grouping: false,
3919            });
3920            Some(id)
3921        } else {
3922            None
3923        }
3924    }
3925
3926    fn end_transaction(
3927        &mut self,
3928        now: Instant,
3929        buffer_transactions: HashMap<BufferId, TransactionId>,
3930    ) -> bool {
3931        assert_ne!(self.transaction_depth, 0);
3932        self.transaction_depth -= 1;
3933        if self.transaction_depth == 0 {
3934            if buffer_transactions.is_empty() {
3935                self.undo_stack.pop();
3936                false
3937            } else {
3938                self.redo_stack.clear();
3939                let transaction = self.undo_stack.last_mut().unwrap();
3940                transaction.last_edit_at = now;
3941                for (buffer_id, transaction_id) in buffer_transactions {
3942                    transaction
3943                        .buffer_transactions
3944                        .entry(buffer_id)
3945                        .or_insert(transaction_id);
3946                }
3947                true
3948            }
3949        } else {
3950            false
3951        }
3952    }
3953
3954    fn push_transaction<'a, T>(
3955        &mut self,
3956        buffer_transactions: T,
3957        now: Instant,
3958        cx: &mut ModelContext<MultiBuffer>,
3959    ) where
3960        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
3961    {
3962        assert_eq!(self.transaction_depth, 0);
3963        let transaction = Transaction {
3964            id: self.next_transaction_id.tick(),
3965            buffer_transactions: buffer_transactions
3966                .into_iter()
3967                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
3968                .collect(),
3969            first_edit_at: now,
3970            last_edit_at: now,
3971            suppress_grouping: false,
3972        };
3973        if !transaction.buffer_transactions.is_empty() {
3974            self.undo_stack.push(transaction);
3975            self.redo_stack.clear();
3976        }
3977    }
3978
3979    fn finalize_last_transaction(&mut self) {
3980        if let Some(transaction) = self.undo_stack.last_mut() {
3981            transaction.suppress_grouping = true;
3982        }
3983    }
3984
3985    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
3986        if let Some(ix) = self
3987            .undo_stack
3988            .iter()
3989            .rposition(|transaction| transaction.id == transaction_id)
3990        {
3991            Some(self.undo_stack.remove(ix))
3992        } else if let Some(ix) = self
3993            .redo_stack
3994            .iter()
3995            .rposition(|transaction| transaction.id == transaction_id)
3996        {
3997            Some(self.redo_stack.remove(ix))
3998        } else {
3999            None
4000        }
4001    }
4002
4003    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
4004        self.undo_stack
4005            .iter()
4006            .find(|transaction| transaction.id == transaction_id)
4007            .or_else(|| {
4008                self.redo_stack
4009                    .iter()
4010                    .find(|transaction| transaction.id == transaction_id)
4011            })
4012    }
4013
4014    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
4015        self.undo_stack
4016            .iter_mut()
4017            .find(|transaction| transaction.id == transaction_id)
4018            .or_else(|| {
4019                self.redo_stack
4020                    .iter_mut()
4021                    .find(|transaction| transaction.id == transaction_id)
4022            })
4023    }
4024
4025    fn pop_undo(&mut self) -> Option<&mut Transaction> {
4026        assert_eq!(self.transaction_depth, 0);
4027        if let Some(transaction) = self.undo_stack.pop() {
4028            self.redo_stack.push(transaction);
4029            self.redo_stack.last_mut()
4030        } else {
4031            None
4032        }
4033    }
4034
4035    fn pop_redo(&mut self) -> Option<&mut Transaction> {
4036        assert_eq!(self.transaction_depth, 0);
4037        if let Some(transaction) = self.redo_stack.pop() {
4038            self.undo_stack.push(transaction);
4039            self.undo_stack.last_mut()
4040        } else {
4041            None
4042        }
4043    }
4044
4045    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
4046        let ix = self
4047            .undo_stack
4048            .iter()
4049            .rposition(|transaction| transaction.id == transaction_id)?;
4050        let transaction = self.undo_stack.remove(ix);
4051        self.redo_stack.push(transaction);
4052        self.redo_stack.last()
4053    }
4054
4055    fn group(&mut self) -> Option<TransactionId> {
4056        let mut count = 0;
4057        let mut transactions = self.undo_stack.iter();
4058        if let Some(mut transaction) = transactions.next_back() {
4059            while let Some(prev_transaction) = transactions.next_back() {
4060                if !prev_transaction.suppress_grouping
4061                    && transaction.first_edit_at - prev_transaction.last_edit_at
4062                        <= self.group_interval
4063                {
4064                    transaction = prev_transaction;
4065                    count += 1;
4066                } else {
4067                    break;
4068                }
4069            }
4070        }
4071        self.group_trailing(count)
4072    }
4073
4074    fn group_until(&mut self, transaction_id: TransactionId) {
4075        let mut count = 0;
4076        for transaction in self.undo_stack.iter().rev() {
4077            if transaction.id == transaction_id {
4078                self.group_trailing(count);
4079                break;
4080            } else if transaction.suppress_grouping {
4081                break;
4082            } else {
4083                count += 1;
4084            }
4085        }
4086    }
4087
4088    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
4089        let new_len = self.undo_stack.len() - n;
4090        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
4091        if let Some(last_transaction) = transactions_to_keep.last_mut() {
4092            if let Some(transaction) = transactions_to_merge.last() {
4093                last_transaction.last_edit_at = transaction.last_edit_at;
4094            }
4095            for to_merge in transactions_to_merge {
4096                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
4097                    last_transaction
4098                        .buffer_transactions
4099                        .entry(*buffer_id)
4100                        .or_insert(*transaction_id);
4101                }
4102            }
4103        }
4104
4105        self.undo_stack.truncate(new_len);
4106        self.undo_stack.last().map(|t| t.id)
4107    }
4108}
4109
4110impl Excerpt {
4111    fn new(
4112        id: ExcerptId,
4113        locator: Locator,
4114        buffer_id: BufferId,
4115        buffer: BufferSnapshot,
4116        range: ExcerptRange<text::Anchor>,
4117        has_trailing_newline: bool,
4118    ) -> Self {
4119        Excerpt {
4120            id,
4121            locator,
4122            max_buffer_row: range.context.end.to_point(&buffer).row,
4123            text_summary: buffer
4124                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
4125            buffer_id,
4126            buffer,
4127            range,
4128            has_trailing_newline,
4129        }
4130    }
4131
4132    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
4133        let content_start = self.range.context.start.to_offset(&self.buffer);
4134        let chunks_start = content_start + range.start;
4135        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
4136
4137        let footer_height = if self.has_trailing_newline
4138            && range.start <= self.text_summary.len
4139            && range.end > self.text_summary.len
4140        {
4141            1
4142        } else {
4143            0
4144        };
4145
4146        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
4147
4148        ExcerptChunks {
4149            excerpt_id: self.id,
4150            content_chunks,
4151            footer_height,
4152        }
4153    }
4154
4155    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, offset: usize) {
4156        let content_start = self.range.context.start.to_offset(&self.buffer);
4157        let chunks_start = content_start + offset;
4158        excerpt_chunks.content_chunks.seek(chunks_start);
4159    }
4160
4161    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
4162        let content_start = self.range.context.start.to_offset(&self.buffer);
4163        let bytes_start = content_start + range.start;
4164        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
4165        let footer_height = if self.has_trailing_newline
4166            && range.start <= self.text_summary.len
4167            && range.end > self.text_summary.len
4168        {
4169            1
4170        } else {
4171            0
4172        };
4173        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
4174
4175        ExcerptBytes {
4176            content_bytes,
4177            padding_height: footer_height,
4178            reversed: false,
4179        }
4180    }
4181
4182    fn reversed_bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
4183        let content_start = self.range.context.start.to_offset(&self.buffer);
4184        let bytes_start = content_start + range.start;
4185        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
4186        let footer_height = if self.has_trailing_newline
4187            && range.start <= self.text_summary.len
4188            && range.end > self.text_summary.len
4189        {
4190            1
4191        } else {
4192            0
4193        };
4194        let content_bytes = self.buffer.reversed_bytes_in_range(bytes_start..bytes_end);
4195
4196        ExcerptBytes {
4197            content_bytes,
4198            padding_height: footer_height,
4199            reversed: true,
4200        }
4201    }
4202
4203    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
4204        if text_anchor
4205            .cmp(&self.range.context.start, &self.buffer)
4206            .is_lt()
4207        {
4208            self.range.context.start
4209        } else if text_anchor
4210            .cmp(&self.range.context.end, &self.buffer)
4211            .is_gt()
4212        {
4213            self.range.context.end
4214        } else {
4215            text_anchor
4216        }
4217    }
4218
4219    fn contains(&self, anchor: &Anchor) -> bool {
4220        Some(self.buffer_id) == anchor.buffer_id
4221            && self
4222                .range
4223                .context
4224                .start
4225                .cmp(&anchor.text_anchor, &self.buffer)
4226                .is_le()
4227            && self
4228                .range
4229                .context
4230                .end
4231                .cmp(&anchor.text_anchor, &self.buffer)
4232                .is_ge()
4233    }
4234
4235    /// The [`Excerpt`]'s start offset in its [`Buffer`]
4236    fn buffer_start_offset(&self) -> usize {
4237        self.range.context.start.to_offset(&self.buffer)
4238    }
4239
4240    /// The [`Excerpt`]'s end offset in its [`Buffer`]
4241    fn buffer_end_offset(&self) -> usize {
4242        self.buffer_start_offset() + self.text_summary.len
4243    }
4244}
4245
4246impl<'a> MultiBufferExcerpt<'a> {
4247    fn new(excerpt: &'a Excerpt, excerpt_offset: usize) -> Self {
4248        MultiBufferExcerpt {
4249            excerpt,
4250            excerpt_offset,
4251        }
4252    }
4253
4254    pub fn buffer(&self) -> &'a BufferSnapshot {
4255        &self.excerpt.buffer
4256    }
4257
4258    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
4259    pub fn map_offset_to_buffer(&self, offset: usize) -> usize {
4260        self.excerpt.buffer_start_offset() + offset.saturating_sub(self.excerpt_offset)
4261    }
4262
4263    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
4264    pub fn map_range_to_buffer(&self, range: Range<usize>) -> Range<usize> {
4265        self.map_offset_to_buffer(range.start)..self.map_offset_to_buffer(range.end)
4266    }
4267
4268    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
4269    pub fn map_offset_from_buffer(&self, buffer_offset: usize) -> usize {
4270        let mut buffer_offset_in_excerpt =
4271            buffer_offset.saturating_sub(self.excerpt.buffer_start_offset());
4272        buffer_offset_in_excerpt =
4273            cmp::min(buffer_offset_in_excerpt, self.excerpt.text_summary.len);
4274
4275        self.excerpt_offset + buffer_offset_in_excerpt
4276    }
4277
4278    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
4279    pub fn map_range_from_buffer(&self, buffer_range: Range<usize>) -> Range<usize> {
4280        self.map_offset_from_buffer(buffer_range.start)
4281            ..self.map_offset_from_buffer(buffer_range.end)
4282    }
4283
4284    /// Returns true if the entirety of the given range is in the buffer's excerpt
4285    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
4286        range.start >= self.excerpt.buffer_start_offset()
4287            && range.end <= self.excerpt.buffer_end_offset()
4288    }
4289}
4290
4291impl ExcerptId {
4292    pub fn min() -> Self {
4293        Self(0)
4294    }
4295
4296    pub fn max() -> Self {
4297        Self(usize::MAX)
4298    }
4299
4300    pub fn to_proto(&self) -> u64 {
4301        self.0 as _
4302    }
4303
4304    pub fn from_proto(proto: u64) -> Self {
4305        Self(proto as _)
4306    }
4307
4308    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
4309        let a = snapshot.excerpt_locator_for_id(*self);
4310        let b = snapshot.excerpt_locator_for_id(*other);
4311        a.cmp(b).then_with(|| self.0.cmp(&other.0))
4312    }
4313}
4314
4315impl Into<usize> for ExcerptId {
4316    fn into(self) -> usize {
4317        self.0
4318    }
4319}
4320
4321impl fmt::Debug for Excerpt {
4322    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4323        f.debug_struct("Excerpt")
4324            .field("id", &self.id)
4325            .field("locator", &self.locator)
4326            .field("buffer_id", &self.buffer_id)
4327            .field("range", &self.range)
4328            .field("text_summary", &self.text_summary)
4329            .field("has_trailing_newline", &self.has_trailing_newline)
4330            .finish()
4331    }
4332}
4333
4334impl sum_tree::Item for Excerpt {
4335    type Summary = ExcerptSummary;
4336
4337    fn summary(&self) -> Self::Summary {
4338        let mut text = self.text_summary.clone();
4339        if self.has_trailing_newline {
4340            text += TextSummary::from("\n");
4341        }
4342        ExcerptSummary {
4343            excerpt_id: self.id,
4344            excerpt_locator: self.locator.clone(),
4345            max_buffer_row: MultiBufferRow(self.max_buffer_row),
4346            text,
4347        }
4348    }
4349}
4350
4351impl sum_tree::Item for ExcerptIdMapping {
4352    type Summary = ExcerptId;
4353
4354    fn summary(&self) -> Self::Summary {
4355        self.id
4356    }
4357}
4358
4359impl sum_tree::KeyedItem for ExcerptIdMapping {
4360    type Key = ExcerptId;
4361
4362    fn key(&self) -> Self::Key {
4363        self.id
4364    }
4365}
4366
4367impl sum_tree::Summary for ExcerptId {
4368    type Context = ();
4369
4370    fn add_summary(&mut self, other: &Self, _: &()) {
4371        *self = *other;
4372    }
4373}
4374
4375impl sum_tree::Summary for ExcerptSummary {
4376    type Context = ();
4377
4378    fn add_summary(&mut self, summary: &Self, _: &()) {
4379        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
4380        self.excerpt_locator = summary.excerpt_locator.clone();
4381        self.text.add_summary(&summary.text, &());
4382        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
4383    }
4384}
4385
4386impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
4387    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4388        *self += &summary.text;
4389    }
4390}
4391
4392impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
4393    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4394        *self += summary.text.len;
4395    }
4396}
4397
4398impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
4399    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
4400        Ord::cmp(self, &cursor_location.text.len)
4401    }
4402}
4403
4404impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
4405    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
4406        Ord::cmp(&Some(self), cursor_location)
4407    }
4408}
4409
4410impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
4411    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
4412        Ord::cmp(self, &cursor_location.excerpt_locator)
4413    }
4414}
4415
4416impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for OffsetUtf16 {
4417    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4418        *self += summary.text.len_utf16;
4419    }
4420}
4421
4422impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
4423    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4424        *self += summary.text.lines;
4425    }
4426}
4427
4428impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
4429    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4430        *self += summary.text.lines_utf16()
4431    }
4432}
4433
4434impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
4435    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4436        *self = Some(&summary.excerpt_locator);
4437    }
4438}
4439
4440impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
4441    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4442        *self = Some(summary.excerpt_id);
4443    }
4444}
4445
4446impl<'a> MultiBufferRows<'a> {
4447    pub fn seek(&mut self, row: MultiBufferRow) {
4448        self.buffer_row_range = 0..0;
4449
4450        self.excerpts
4451            .seek_forward(&Point::new(row.0, 0), Bias::Right, &());
4452        if self.excerpts.item().is_none() {
4453            self.excerpts.prev(&());
4454
4455            if self.excerpts.item().is_none() && row.0 == 0 {
4456                self.buffer_row_range = 0..1;
4457                return;
4458            }
4459        }
4460
4461        if let Some(excerpt) = self.excerpts.item() {
4462            let overshoot = row.0 - self.excerpts.start().row;
4463            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
4464            self.buffer_row_range.start = excerpt_start + overshoot;
4465            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
4466        }
4467    }
4468}
4469
4470impl<'a> Iterator for MultiBufferRows<'a> {
4471    type Item = Option<u32>;
4472
4473    fn next(&mut self) -> Option<Self::Item> {
4474        loop {
4475            if !self.buffer_row_range.is_empty() {
4476                let row = Some(self.buffer_row_range.start);
4477                self.buffer_row_range.start += 1;
4478                return Some(row);
4479            }
4480            self.excerpts.item()?;
4481            self.excerpts.next(&());
4482            let excerpt = self.excerpts.item()?;
4483            self.buffer_row_range.start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
4484            self.buffer_row_range.end =
4485                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
4486        }
4487    }
4488}
4489
4490impl<'a> MultiBufferChunks<'a> {
4491    pub fn offset(&self) -> usize {
4492        self.range.start
4493    }
4494
4495    pub fn seek(&mut self, offset: usize) {
4496        self.range.start = offset;
4497        self.excerpts.seek(&offset, Bias::Right, &());
4498        if let Some(excerpt) = self.excerpts.item() {
4499            let excerpt_start = self.excerpts.start();
4500            if let Some(excerpt_chunks) = self
4501                .excerpt_chunks
4502                .as_mut()
4503                .filter(|chunks| excerpt.id == chunks.excerpt_id)
4504            {
4505                excerpt.seek_chunks(excerpt_chunks, self.range.start - excerpt_start);
4506            } else {
4507                self.excerpt_chunks = Some(excerpt.chunks_in_range(
4508                    self.range.start - excerpt_start..self.range.end - excerpt_start,
4509                    self.language_aware,
4510                ));
4511            }
4512        } else {
4513            self.excerpt_chunks = None;
4514        }
4515    }
4516}
4517
4518impl<'a> Iterator for MultiBufferChunks<'a> {
4519    type Item = Chunk<'a>;
4520
4521    fn next(&mut self) -> Option<Self::Item> {
4522        if self.range.is_empty() {
4523            None
4524        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
4525            self.range.start += chunk.text.len();
4526            Some(chunk)
4527        } else {
4528            self.excerpts.next(&());
4529            let excerpt = self.excerpts.item()?;
4530            self.excerpt_chunks = Some(excerpt.chunks_in_range(
4531                0..self.range.end - self.excerpts.start(),
4532                self.language_aware,
4533            ));
4534            self.next()
4535        }
4536    }
4537}
4538
4539impl<'a> MultiBufferBytes<'a> {
4540    fn consume(&mut self, len: usize) {
4541        self.range.start += len;
4542        self.chunk = &self.chunk[len..];
4543
4544        if !self.range.is_empty() && self.chunk.is_empty() {
4545            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
4546                self.chunk = chunk;
4547            } else {
4548                self.excerpts.next(&());
4549                if let Some(excerpt) = self.excerpts.item() {
4550                    let mut excerpt_bytes =
4551                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
4552                    self.chunk = excerpt_bytes.next().unwrap();
4553                    self.excerpt_bytes = Some(excerpt_bytes);
4554                }
4555            }
4556        }
4557    }
4558}
4559
4560impl<'a> Iterator for MultiBufferBytes<'a> {
4561    type Item = &'a [u8];
4562
4563    fn next(&mut self) -> Option<Self::Item> {
4564        let chunk = self.chunk;
4565        if chunk.is_empty() {
4566            None
4567        } else {
4568            self.consume(chunk.len());
4569            Some(chunk)
4570        }
4571    }
4572}
4573
4574impl<'a> io::Read for MultiBufferBytes<'a> {
4575    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4576        let len = cmp::min(buf.len(), self.chunk.len());
4577        buf[..len].copy_from_slice(&self.chunk[..len]);
4578        if len > 0 {
4579            self.consume(len);
4580        }
4581        Ok(len)
4582    }
4583}
4584
4585impl<'a> ReversedMultiBufferBytes<'a> {
4586    fn consume(&mut self, len: usize) {
4587        self.range.end -= len;
4588        self.chunk = &self.chunk[..self.chunk.len() - len];
4589
4590        if !self.range.is_empty() && self.chunk.is_empty() {
4591            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
4592                self.chunk = chunk;
4593            } else {
4594                self.excerpts.prev(&());
4595                if let Some(excerpt) = self.excerpts.item() {
4596                    let mut excerpt_bytes = excerpt.reversed_bytes_in_range(
4597                        self.range.start.saturating_sub(*self.excerpts.start())..usize::MAX,
4598                    );
4599                    self.chunk = excerpt_bytes.next().unwrap();
4600                    self.excerpt_bytes = Some(excerpt_bytes);
4601                }
4602            }
4603        } else {
4604        }
4605    }
4606}
4607
4608impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
4609    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4610        let len = cmp::min(buf.len(), self.chunk.len());
4611        buf[..len].copy_from_slice(&self.chunk[..len]);
4612        buf[..len].reverse();
4613        if len > 0 {
4614            self.consume(len);
4615        }
4616        Ok(len)
4617    }
4618}
4619impl<'a> Iterator for ExcerptBytes<'a> {
4620    type Item = &'a [u8];
4621
4622    fn next(&mut self) -> Option<Self::Item> {
4623        if self.reversed && self.padding_height > 0 {
4624            let result = &NEWLINES[..self.padding_height];
4625            self.padding_height = 0;
4626            return Some(result);
4627        }
4628
4629        if let Some(chunk) = self.content_bytes.next() {
4630            if !chunk.is_empty() {
4631                return Some(chunk);
4632            }
4633        }
4634
4635        if self.padding_height > 0 {
4636            let result = &NEWLINES[..self.padding_height];
4637            self.padding_height = 0;
4638            return Some(result);
4639        }
4640
4641        None
4642    }
4643}
4644
4645impl<'a> Iterator for ExcerptChunks<'a> {
4646    type Item = Chunk<'a>;
4647
4648    fn next(&mut self) -> Option<Self::Item> {
4649        if let Some(chunk) = self.content_chunks.next() {
4650            return Some(chunk);
4651        }
4652
4653        if self.footer_height > 0 {
4654            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
4655            self.footer_height = 0;
4656            return Some(Chunk {
4657                text,
4658                ..Default::default()
4659            });
4660        }
4661
4662        None
4663    }
4664}
4665
4666impl ToOffset for Point {
4667    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4668        snapshot.point_to_offset(*self)
4669    }
4670}
4671
4672impl ToOffset for usize {
4673    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4674        assert!(*self <= snapshot.len(), "offset is out of range");
4675        *self
4676    }
4677}
4678
4679impl ToOffset for OffsetUtf16 {
4680    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4681        snapshot.offset_utf16_to_offset(*self)
4682    }
4683}
4684
4685impl ToOffset for PointUtf16 {
4686    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4687        snapshot.point_utf16_to_offset(*self)
4688    }
4689}
4690
4691impl ToOffsetUtf16 for OffsetUtf16 {
4692    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4693        *self
4694    }
4695}
4696
4697impl ToOffsetUtf16 for usize {
4698    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4699        snapshot.offset_to_offset_utf16(*self)
4700    }
4701}
4702
4703impl ToPoint for usize {
4704    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
4705        snapshot.offset_to_point(*self)
4706    }
4707}
4708
4709impl ToPoint for Point {
4710    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
4711        *self
4712    }
4713}
4714
4715impl ToPointUtf16 for usize {
4716    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4717        snapshot.offset_to_point_utf16(*self)
4718    }
4719}
4720
4721impl ToPointUtf16 for Point {
4722    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4723        snapshot.point_to_point_utf16(*self)
4724    }
4725}
4726
4727impl ToPointUtf16 for PointUtf16 {
4728    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
4729        *self
4730    }
4731}
4732
4733pub fn build_excerpt_ranges<T>(
4734    buffer: &BufferSnapshot,
4735    ranges: &[Range<T>],
4736    context_line_count: u32,
4737) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
4738where
4739    T: text::ToPoint,
4740{
4741    let max_point = buffer.max_point();
4742    let mut range_counts = Vec::new();
4743    let mut excerpt_ranges = Vec::new();
4744    let mut range_iter = ranges
4745        .iter()
4746        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
4747        .peekable();
4748    while let Some(range) = range_iter.next() {
4749        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
4750        let row = (range.end.row + context_line_count).min(max_point.row);
4751        let mut excerpt_end = Point::new(row, buffer.line_len(row));
4752
4753        let mut ranges_in_excerpt = 1;
4754
4755        while let Some(next_range) = range_iter.peek() {
4756            if next_range.start.row <= excerpt_end.row + context_line_count {
4757                let row = (next_range.end.row + context_line_count).min(max_point.row);
4758                excerpt_end = Point::new(row, buffer.line_len(row));
4759
4760                ranges_in_excerpt += 1;
4761                range_iter.next();
4762            } else {
4763                break;
4764            }
4765        }
4766
4767        excerpt_ranges.push(ExcerptRange {
4768            context: excerpt_start..excerpt_end,
4769            primary: Some(range),
4770        });
4771        range_counts.push(ranges_in_excerpt);
4772    }
4773
4774    (excerpt_ranges, range_counts)
4775}
4776
4777#[cfg(test)]
4778mod tests {
4779    use super::*;
4780    use futures::StreamExt;
4781    use gpui::{AppContext, Context, TestAppContext};
4782    use language::{Buffer, Rope};
4783    use parking_lot::RwLock;
4784    use rand::prelude::*;
4785    use settings::SettingsStore;
4786    use std::env;
4787    use util::test::sample_text;
4788
4789    #[ctor::ctor]
4790    fn init_logger() {
4791        if std::env::var("RUST_LOG").is_ok() {
4792            env_logger::init();
4793        }
4794    }
4795
4796    #[gpui::test]
4797    fn test_singleton(cx: &mut AppContext) {
4798        let buffer = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
4799        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4800
4801        let snapshot = multibuffer.read(cx).snapshot(cx);
4802        assert_eq!(snapshot.text(), buffer.read(cx).text());
4803
4804        assert_eq!(
4805            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4806            (0..buffer.read(cx).row_count())
4807                .map(Some)
4808                .collect::<Vec<_>>()
4809        );
4810
4811        buffer.update(cx, |buffer, cx| buffer.edit([(1..3, "XXX\n")], None, cx));
4812        let snapshot = multibuffer.read(cx).snapshot(cx);
4813
4814        assert_eq!(snapshot.text(), buffer.read(cx).text());
4815        assert_eq!(
4816            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4817            (0..buffer.read(cx).row_count())
4818                .map(Some)
4819                .collect::<Vec<_>>()
4820        );
4821    }
4822
4823    #[gpui::test]
4824    fn test_remote(cx: &mut AppContext) {
4825        let host_buffer = cx.new_model(|cx| Buffer::local("a", cx));
4826        let guest_buffer = cx.new_model(|cx| {
4827            let state = host_buffer.read(cx).to_proto(cx);
4828            let ops = cx
4829                .background_executor()
4830                .block(host_buffer.read(cx).serialize_ops(None, cx));
4831            let mut buffer = Buffer::from_proto(1, Capability::ReadWrite, state, None).unwrap();
4832            buffer
4833                .apply_ops(
4834                    ops.into_iter()
4835                        .map(|op| language::proto::deserialize_operation(op).unwrap()),
4836                    cx,
4837                )
4838                .unwrap();
4839            buffer
4840        });
4841        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
4842        let snapshot = multibuffer.read(cx).snapshot(cx);
4843        assert_eq!(snapshot.text(), "a");
4844
4845        guest_buffer.update(cx, |buffer, cx| buffer.edit([(1..1, "b")], None, cx));
4846        let snapshot = multibuffer.read(cx).snapshot(cx);
4847        assert_eq!(snapshot.text(), "ab");
4848
4849        guest_buffer.update(cx, |buffer, cx| buffer.edit([(2..2, "c")], None, cx));
4850        let snapshot = multibuffer.read(cx).snapshot(cx);
4851        assert_eq!(snapshot.text(), "abc");
4852    }
4853
4854    #[gpui::test]
4855    fn test_excerpt_boundaries_and_clipping(cx: &mut AppContext) {
4856        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
4857        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
4858        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4859
4860        let events = Arc::new(RwLock::new(Vec::<Event>::new()));
4861        multibuffer.update(cx, |_, cx| {
4862            let events = events.clone();
4863            cx.subscribe(&multibuffer, move |_, _, event, _| {
4864                if let Event::Edited { .. } = event {
4865                    events.write().push(event.clone())
4866                }
4867            })
4868            .detach();
4869        });
4870
4871        let subscription = multibuffer.update(cx, |multibuffer, cx| {
4872            let subscription = multibuffer.subscribe();
4873            multibuffer.push_excerpts(
4874                buffer_1.clone(),
4875                [ExcerptRange {
4876                    context: Point::new(1, 2)..Point::new(2, 5),
4877                    primary: None,
4878                }],
4879                cx,
4880            );
4881            assert_eq!(
4882                subscription.consume().into_inner(),
4883                [Edit {
4884                    old: 0..0,
4885                    new: 0..10
4886                }]
4887            );
4888
4889            multibuffer.push_excerpts(
4890                buffer_1.clone(),
4891                [ExcerptRange {
4892                    context: Point::new(3, 3)..Point::new(4, 4),
4893                    primary: None,
4894                }],
4895                cx,
4896            );
4897            multibuffer.push_excerpts(
4898                buffer_2.clone(),
4899                [ExcerptRange {
4900                    context: Point::new(3, 1)..Point::new(3, 3),
4901                    primary: None,
4902                }],
4903                cx,
4904            );
4905            assert_eq!(
4906                subscription.consume().into_inner(),
4907                [Edit {
4908                    old: 10..10,
4909                    new: 10..22
4910                }]
4911            );
4912
4913            subscription
4914        });
4915
4916        // Adding excerpts emits an edited event.
4917        assert_eq!(
4918            events.read().as_slice(),
4919            &[
4920                Event::Edited {
4921                    singleton_buffer_edited: false
4922                },
4923                Event::Edited {
4924                    singleton_buffer_edited: false
4925                },
4926                Event::Edited {
4927                    singleton_buffer_edited: false
4928                }
4929            ]
4930        );
4931
4932        let snapshot = multibuffer.read(cx).snapshot(cx);
4933        assert_eq!(
4934            snapshot.text(),
4935            concat!(
4936                "bbbb\n",  // Preserve newlines
4937                "ccccc\n", //
4938                "ddd\n",   //
4939                "eeee\n",  //
4940                "jj"       //
4941            )
4942        );
4943        assert_eq!(
4944            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4945            [Some(1), Some(2), Some(3), Some(4), Some(3)]
4946        );
4947        assert_eq!(
4948            snapshot.buffer_rows(MultiBufferRow(2)).collect::<Vec<_>>(),
4949            [Some(3), Some(4), Some(3)]
4950        );
4951        assert_eq!(
4952            snapshot.buffer_rows(MultiBufferRow(4)).collect::<Vec<_>>(),
4953            [Some(3)]
4954        );
4955        assert_eq!(
4956            snapshot.buffer_rows(MultiBufferRow(5)).collect::<Vec<_>>(),
4957            []
4958        );
4959
4960        assert_eq!(
4961            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
4962            &[
4963                (MultiBufferRow(0), "bbbb\nccccc".to_string(), true),
4964                (MultiBufferRow(2), "ddd\neeee".to_string(), false),
4965                (MultiBufferRow(4), "jj".to_string(), true),
4966            ]
4967        );
4968        assert_eq!(
4969            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
4970            &[(MultiBufferRow(0), "bbbb\nccccc".to_string(), true)]
4971        );
4972        assert_eq!(
4973            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
4974            &[]
4975        );
4976        assert_eq!(
4977            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
4978            &[]
4979        );
4980        assert_eq!(
4981            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4982            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4983        );
4984        assert_eq!(
4985            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4986            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4987        );
4988        assert_eq!(
4989            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
4990            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4991        );
4992        assert_eq!(
4993            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
4994            &[(MultiBufferRow(4), "jj".to_string(), true)]
4995        );
4996        assert_eq!(
4997            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
4998            &[]
4999        );
5000
5001        buffer_1.update(cx, |buffer, cx| {
5002            let text = "\n";
5003            buffer.edit(
5004                [
5005                    (Point::new(0, 0)..Point::new(0, 0), text),
5006                    (Point::new(2, 1)..Point::new(2, 3), text),
5007                ],
5008                None,
5009                cx,
5010            );
5011        });
5012
5013        let snapshot = multibuffer.read(cx).snapshot(cx);
5014        assert_eq!(
5015            snapshot.text(),
5016            concat!(
5017                "bbbb\n", // Preserve newlines
5018                "c\n",    //
5019                "cc\n",   //
5020                "ddd\n",  //
5021                "eeee\n", //
5022                "jj"      //
5023            )
5024        );
5025
5026        assert_eq!(
5027            subscription.consume().into_inner(),
5028            [Edit {
5029                old: 6..8,
5030                new: 6..7
5031            }]
5032        );
5033
5034        let snapshot = multibuffer.read(cx).snapshot(cx);
5035        assert_eq!(
5036            snapshot.clip_point(Point::new(0, 5), Bias::Left),
5037            Point::new(0, 4)
5038        );
5039        assert_eq!(
5040            snapshot.clip_point(Point::new(0, 5), Bias::Right),
5041            Point::new(0, 4)
5042        );
5043        assert_eq!(
5044            snapshot.clip_point(Point::new(5, 1), Bias::Right),
5045            Point::new(5, 1)
5046        );
5047        assert_eq!(
5048            snapshot.clip_point(Point::new(5, 2), Bias::Right),
5049            Point::new(5, 2)
5050        );
5051        assert_eq!(
5052            snapshot.clip_point(Point::new(5, 3), Bias::Right),
5053            Point::new(5, 2)
5054        );
5055
5056        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
5057            let (buffer_2_excerpt_id, _) =
5058                multibuffer.excerpts_for_buffer(&buffer_2, cx)[0].clone();
5059            multibuffer.remove_excerpts([buffer_2_excerpt_id], cx);
5060            multibuffer.snapshot(cx)
5061        });
5062
5063        assert_eq!(
5064            snapshot.text(),
5065            concat!(
5066                "bbbb\n", // Preserve newlines
5067                "c\n",    //
5068                "cc\n",   //
5069                "ddd\n",  //
5070                "eeee",   //
5071            )
5072        );
5073
5074        fn boundaries_in_range(
5075            range: Range<Point>,
5076            snapshot: &MultiBufferSnapshot,
5077        ) -> Vec<(MultiBufferRow, String, bool)> {
5078            snapshot
5079                .excerpt_boundaries_in_range(range)
5080                .filter_map(|boundary| {
5081                    let starts_new_buffer = boundary.starts_new_buffer();
5082                    boundary.next.map(|next| {
5083                        (
5084                            boundary.row,
5085                            next.buffer
5086                                .text_for_range(next.range.context)
5087                                .collect::<String>(),
5088                            starts_new_buffer,
5089                        )
5090                    })
5091                })
5092                .collect::<Vec<_>>()
5093        }
5094    }
5095
5096    #[gpui::test]
5097    fn test_excerpt_events(cx: &mut AppContext) {
5098        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(10, 3, 'a'), cx));
5099        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(10, 3, 'm'), cx));
5100
5101        let leader_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5102        let follower_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5103        let follower_edit_event_count = Arc::new(RwLock::new(0));
5104
5105        follower_multibuffer.update(cx, |_, cx| {
5106            let follower_edit_event_count = follower_edit_event_count.clone();
5107            cx.subscribe(
5108                &leader_multibuffer,
5109                move |follower, _, event, cx| match event.clone() {
5110                    Event::ExcerptsAdded {
5111                        buffer,
5112                        predecessor,
5113                        excerpts,
5114                    } => follower.insert_excerpts_with_ids_after(predecessor, buffer, excerpts, cx),
5115                    Event::ExcerptsRemoved { ids } => follower.remove_excerpts(ids, cx),
5116                    Event::Edited { .. } => {
5117                        *follower_edit_event_count.write() += 1;
5118                    }
5119                    _ => {}
5120                },
5121            )
5122            .detach();
5123        });
5124
5125        leader_multibuffer.update(cx, |leader, cx| {
5126            leader.push_excerpts(
5127                buffer_1.clone(),
5128                [
5129                    ExcerptRange {
5130                        context: 0..8,
5131                        primary: None,
5132                    },
5133                    ExcerptRange {
5134                        context: 12..16,
5135                        primary: None,
5136                    },
5137                ],
5138                cx,
5139            );
5140            leader.insert_excerpts_after(
5141                leader.excerpt_ids()[0],
5142                buffer_2.clone(),
5143                [
5144                    ExcerptRange {
5145                        context: 0..5,
5146                        primary: None,
5147                    },
5148                    ExcerptRange {
5149                        context: 10..15,
5150                        primary: None,
5151                    },
5152                ],
5153                cx,
5154            )
5155        });
5156        assert_eq!(
5157            leader_multibuffer.read(cx).snapshot(cx).text(),
5158            follower_multibuffer.read(cx).snapshot(cx).text(),
5159        );
5160        assert_eq!(*follower_edit_event_count.read(), 2);
5161
5162        leader_multibuffer.update(cx, |leader, cx| {
5163            let excerpt_ids = leader.excerpt_ids();
5164            leader.remove_excerpts([excerpt_ids[1], excerpt_ids[3]], cx);
5165        });
5166        assert_eq!(
5167            leader_multibuffer.read(cx).snapshot(cx).text(),
5168            follower_multibuffer.read(cx).snapshot(cx).text(),
5169        );
5170        assert_eq!(*follower_edit_event_count.read(), 3);
5171
5172        // Removing an empty set of excerpts is a noop.
5173        leader_multibuffer.update(cx, |leader, cx| {
5174            leader.remove_excerpts([], cx);
5175        });
5176        assert_eq!(
5177            leader_multibuffer.read(cx).snapshot(cx).text(),
5178            follower_multibuffer.read(cx).snapshot(cx).text(),
5179        );
5180        assert_eq!(*follower_edit_event_count.read(), 3);
5181
5182        // Adding an empty set of excerpts is a noop.
5183        leader_multibuffer.update(cx, |leader, cx| {
5184            leader.push_excerpts::<usize>(buffer_2.clone(), [], cx);
5185        });
5186        assert_eq!(
5187            leader_multibuffer.read(cx).snapshot(cx).text(),
5188            follower_multibuffer.read(cx).snapshot(cx).text(),
5189        );
5190        assert_eq!(*follower_edit_event_count.read(), 3);
5191
5192        leader_multibuffer.update(cx, |leader, cx| {
5193            leader.clear(cx);
5194        });
5195        assert_eq!(
5196            leader_multibuffer.read(cx).snapshot(cx).text(),
5197            follower_multibuffer.read(cx).snapshot(cx).text(),
5198        );
5199        assert_eq!(*follower_edit_event_count.read(), 4);
5200    }
5201
5202    #[gpui::test]
5203    fn test_expand_excerpts(cx: &mut AppContext) {
5204        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5205        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5206
5207        multibuffer.update(cx, |multibuffer, cx| {
5208            multibuffer.push_excerpts_with_context_lines(
5209                buffer.clone(),
5210                vec![
5211                    // Note that in this test, this first excerpt
5212                    // does not contain a new line
5213                    Point::new(3, 2)..Point::new(3, 3),
5214                    Point::new(7, 1)..Point::new(7, 3),
5215                    Point::new(15, 0)..Point::new(15, 0),
5216                ],
5217                1,
5218                cx,
5219            )
5220        });
5221
5222        let snapshot = multibuffer.read(cx).snapshot(cx);
5223
5224        assert_eq!(
5225            snapshot.text(),
5226            concat!(
5227                "ccc\n", //
5228                "ddd\n", //
5229                "eee",   //
5230                "\n",    // End of excerpt
5231                "ggg\n", //
5232                "hhh\n", //
5233                "iii",   //
5234                "\n",    // End of excerpt
5235                "ooo\n", //
5236                "ppp\n", //
5237                "qqq",   // End of excerpt
5238            )
5239        );
5240        drop(snapshot);
5241
5242        multibuffer.update(cx, |multibuffer, cx| {
5243            multibuffer.expand_excerpts(
5244                multibuffer.excerpt_ids(),
5245                1,
5246                ExpandExcerptDirection::UpAndDown,
5247                cx,
5248            )
5249        });
5250
5251        let snapshot = multibuffer.read(cx).snapshot(cx);
5252
5253        // Expanding context lines causes the line containing 'fff' to appear in two different excerpts.
5254        // We don't attempt to merge them, because removing the excerpt could create inconsistency with other layers
5255        // that are tracking excerpt ids.
5256        assert_eq!(
5257            snapshot.text(),
5258            concat!(
5259                "bbb\n", //
5260                "ccc\n", //
5261                "ddd\n", //
5262                "eee\n", //
5263                "fff\n", // End of excerpt
5264                "fff\n", //
5265                "ggg\n", //
5266                "hhh\n", //
5267                "iii\n", //
5268                "jjj\n", // End of excerpt
5269                "nnn\n", //
5270                "ooo\n", //
5271                "ppp\n", //
5272                "qqq\n", //
5273                "rrr",   // End of excerpt
5274            )
5275        );
5276    }
5277
5278    #[gpui::test]
5279    fn test_push_excerpts_with_context_lines(cx: &mut AppContext) {
5280        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5281        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5282        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
5283            multibuffer.push_excerpts_with_context_lines(
5284                buffer.clone(),
5285                vec![
5286                    // Note that in this test, this first excerpt
5287                    // does contain a new line
5288                    Point::new(3, 2)..Point::new(4, 2),
5289                    Point::new(7, 1)..Point::new(7, 3),
5290                    Point::new(15, 0)..Point::new(15, 0),
5291                ],
5292                2,
5293                cx,
5294            )
5295        });
5296
5297        let snapshot = multibuffer.read(cx).snapshot(cx);
5298        assert_eq!(
5299            snapshot.text(),
5300            concat!(
5301                "bbb\n", // Preserve newlines
5302                "ccc\n", //
5303                "ddd\n", //
5304                "eee\n", //
5305                "fff\n", //
5306                "ggg\n", //
5307                "hhh\n", //
5308                "iii\n", //
5309                "jjj\n", //
5310                "nnn\n", //
5311                "ooo\n", //
5312                "ppp\n", //
5313                "qqq\n", //
5314                "rrr",   //
5315            )
5316        );
5317
5318        assert_eq!(
5319            anchor_ranges
5320                .iter()
5321                .map(|range| range.to_point(&snapshot))
5322                .collect::<Vec<_>>(),
5323            vec![
5324                Point::new(2, 2)..Point::new(3, 2),
5325                Point::new(6, 1)..Point::new(6, 3),
5326                Point::new(11, 0)..Point::new(11, 0)
5327            ]
5328        );
5329    }
5330
5331    #[gpui::test]
5332    async fn test_stream_excerpts_with_context_lines(cx: &mut TestAppContext) {
5333        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5334        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5335        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
5336            let snapshot = buffer.read(cx);
5337            let ranges = vec![
5338                snapshot.anchor_before(Point::new(3, 2))..snapshot.anchor_before(Point::new(4, 2)),
5339                snapshot.anchor_before(Point::new(7, 1))..snapshot.anchor_before(Point::new(7, 3)),
5340                snapshot.anchor_before(Point::new(15, 0))
5341                    ..snapshot.anchor_before(Point::new(15, 0)),
5342            ];
5343            multibuffer.stream_excerpts_with_context_lines(buffer.clone(), ranges, 2, cx)
5344        });
5345
5346        let anchor_ranges = anchor_ranges.collect::<Vec<_>>().await;
5347
5348        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
5349        assert_eq!(
5350            snapshot.text(),
5351            concat!(
5352                "bbb\n", //
5353                "ccc\n", //
5354                "ddd\n", //
5355                "eee\n", //
5356                "fff\n", //
5357                "ggg\n", //
5358                "hhh\n", //
5359                "iii\n", //
5360                "jjj\n", //
5361                "nnn\n", //
5362                "ooo\n", //
5363                "ppp\n", //
5364                "qqq\n", //
5365                "rrr",   //
5366            )
5367        );
5368
5369        assert_eq!(
5370            anchor_ranges
5371                .iter()
5372                .map(|range| range.to_point(&snapshot))
5373                .collect::<Vec<_>>(),
5374            vec![
5375                Point::new(2, 2)..Point::new(3, 2),
5376                Point::new(6, 1)..Point::new(6, 3),
5377                Point::new(11, 0)..Point::new(11, 0)
5378            ]
5379        );
5380    }
5381
5382    #[gpui::test]
5383    fn test_empty_multibuffer(cx: &mut AppContext) {
5384        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5385
5386        let snapshot = multibuffer.read(cx).snapshot(cx);
5387        assert_eq!(snapshot.text(), "");
5388        assert_eq!(
5389            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
5390            &[Some(0)]
5391        );
5392        assert_eq!(
5393            snapshot.buffer_rows(MultiBufferRow(1)).collect::<Vec<_>>(),
5394            &[]
5395        );
5396    }
5397
5398    #[gpui::test]
5399    fn test_singleton_multibuffer_anchors(cx: &mut AppContext) {
5400        let buffer = cx.new_model(|cx| Buffer::local("abcd", cx));
5401        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
5402        let old_snapshot = multibuffer.read(cx).snapshot(cx);
5403        buffer.update(cx, |buffer, cx| {
5404            buffer.edit([(0..0, "X")], None, cx);
5405            buffer.edit([(5..5, "Y")], None, cx);
5406        });
5407        let new_snapshot = multibuffer.read(cx).snapshot(cx);
5408
5409        assert_eq!(old_snapshot.text(), "abcd");
5410        assert_eq!(new_snapshot.text(), "XabcdY");
5411
5412        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
5413        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
5414        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
5415        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
5416    }
5417
5418    #[gpui::test]
5419    fn test_multibuffer_anchors(cx: &mut AppContext) {
5420        let buffer_1 = cx.new_model(|cx| Buffer::local("abcd", cx));
5421        let buffer_2 = cx.new_model(|cx| Buffer::local("efghi", cx));
5422        let multibuffer = cx.new_model(|cx| {
5423            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
5424            multibuffer.push_excerpts(
5425                buffer_1.clone(),
5426                [ExcerptRange {
5427                    context: 0..4,
5428                    primary: None,
5429                }],
5430                cx,
5431            );
5432            multibuffer.push_excerpts(
5433                buffer_2.clone(),
5434                [ExcerptRange {
5435                    context: 0..5,
5436                    primary: None,
5437                }],
5438                cx,
5439            );
5440            multibuffer
5441        });
5442        let old_snapshot = multibuffer.read(cx).snapshot(cx);
5443
5444        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
5445        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
5446        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
5447        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
5448        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
5449        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
5450
5451        buffer_1.update(cx, |buffer, cx| {
5452            buffer.edit([(0..0, "W")], None, cx);
5453            buffer.edit([(5..5, "X")], None, cx);
5454        });
5455        buffer_2.update(cx, |buffer, cx| {
5456            buffer.edit([(0..0, "Y")], None, cx);
5457            buffer.edit([(6..6, "Z")], None, cx);
5458        });
5459        let new_snapshot = multibuffer.read(cx).snapshot(cx);
5460
5461        assert_eq!(old_snapshot.text(), "abcd\nefghi");
5462        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
5463
5464        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
5465        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
5466        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
5467        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
5468        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
5469        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
5470        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
5471        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
5472        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
5473        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
5474    }
5475
5476    #[gpui::test]
5477    fn test_resolving_anchors_after_replacing_their_excerpts(cx: &mut AppContext) {
5478        let buffer_1 = cx.new_model(|cx| Buffer::local("abcd", cx));
5479        let buffer_2 = cx.new_model(|cx| Buffer::local("ABCDEFGHIJKLMNOP", cx));
5480        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5481
5482        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
5483        // Add an excerpt from buffer 1 that spans this new insertion.
5484        buffer_1.update(cx, |buffer, cx| buffer.edit([(4..4, "123")], None, cx));
5485        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
5486            multibuffer
5487                .push_excerpts(
5488                    buffer_1.clone(),
5489                    [ExcerptRange {
5490                        context: 0..7,
5491                        primary: None,
5492                    }],
5493                    cx,
5494                )
5495                .pop()
5496                .unwrap()
5497        });
5498
5499        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
5500        assert_eq!(snapshot_1.text(), "abcd123");
5501
5502        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
5503        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
5504            multibuffer.remove_excerpts([excerpt_id_1], cx);
5505            let mut ids = multibuffer
5506                .push_excerpts(
5507                    buffer_2.clone(),
5508                    [
5509                        ExcerptRange {
5510                            context: 0..4,
5511                            primary: None,
5512                        },
5513                        ExcerptRange {
5514                            context: 6..10,
5515                            primary: None,
5516                        },
5517                        ExcerptRange {
5518                            context: 12..16,
5519                            primary: None,
5520                        },
5521                    ],
5522                    cx,
5523                )
5524                .into_iter();
5525            (ids.next().unwrap(), ids.next().unwrap())
5526        });
5527        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
5528        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
5529
5530        // The old excerpt id doesn't get reused.
5531        assert_ne!(excerpt_id_2, excerpt_id_1);
5532
5533        // Resolve some anchors from the previous snapshot in the new snapshot.
5534        // The current excerpts are from a different buffer, so we don't attempt to
5535        // resolve the old text anchor in the new buffer.
5536        assert_eq!(
5537            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
5538            0
5539        );
5540        assert_eq!(
5541            snapshot_2.summaries_for_anchors::<usize, _>(&[
5542                snapshot_1.anchor_before(2),
5543                snapshot_1.anchor_after(3)
5544            ]),
5545            vec![0, 0]
5546        );
5547
5548        // Refresh anchors from the old snapshot. The return value indicates that both
5549        // anchors lost their original excerpt.
5550        let refresh =
5551            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
5552        assert_eq!(
5553            refresh,
5554            &[
5555                (0, snapshot_2.anchor_before(0), false),
5556                (1, snapshot_2.anchor_after(0), false),
5557            ]
5558        );
5559
5560        // Replace the middle excerpt with a smaller excerpt in buffer 2,
5561        // that intersects the old excerpt.
5562        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
5563            multibuffer.remove_excerpts([excerpt_id_3], cx);
5564            multibuffer
5565                .insert_excerpts_after(
5566                    excerpt_id_2,
5567                    buffer_2.clone(),
5568                    [ExcerptRange {
5569                        context: 5..8,
5570                        primary: None,
5571                    }],
5572                    cx,
5573                )
5574                .pop()
5575                .unwrap()
5576        });
5577
5578        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
5579        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
5580        assert_ne!(excerpt_id_5, excerpt_id_3);
5581
5582        // Resolve some anchors from the previous snapshot in the new snapshot.
5583        // The third anchor can't be resolved, since its excerpt has been removed,
5584        // so it resolves to the same position as its predecessor.
5585        let anchors = [
5586            snapshot_2.anchor_before(0),
5587            snapshot_2.anchor_after(2),
5588            snapshot_2.anchor_after(6),
5589            snapshot_2.anchor_after(14),
5590        ];
5591        assert_eq!(
5592            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
5593            &[0, 2, 9, 13]
5594        );
5595
5596        let new_anchors = snapshot_3.refresh_anchors(&anchors);
5597        assert_eq!(
5598            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
5599            &[(0, true), (1, true), (2, true), (3, true)]
5600        );
5601        assert_eq!(
5602            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
5603            &[0, 2, 7, 13]
5604        );
5605    }
5606
5607    #[gpui::test(iterations = 100)]
5608    fn test_random_multibuffer(cx: &mut AppContext, mut rng: StdRng) {
5609        let operations = env::var("OPERATIONS")
5610            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
5611            .unwrap_or(10);
5612
5613        let mut buffers: Vec<Model<Buffer>> = Vec::new();
5614        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5615        let mut excerpt_ids = Vec::<ExcerptId>::new();
5616        let mut expected_excerpts = Vec::<(Model<Buffer>, Range<text::Anchor>)>::new();
5617        let mut anchors = Vec::new();
5618        let mut old_versions = Vec::new();
5619
5620        for _ in 0..operations {
5621            match rng.gen_range(0..100) {
5622                0..=14 if !buffers.is_empty() => {
5623                    let buffer = buffers.choose(&mut rng).unwrap();
5624                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
5625                }
5626                15..=19 if !expected_excerpts.is_empty() => {
5627                    multibuffer.update(cx, |multibuffer, cx| {
5628                        let ids = multibuffer.excerpt_ids();
5629                        let mut excerpts = HashSet::default();
5630                        for _ in 0..rng.gen_range(0..ids.len()) {
5631                            excerpts.extend(ids.choose(&mut rng).copied());
5632                        }
5633
5634                        let line_count = rng.gen_range(0..5);
5635
5636                        let excerpt_ixs = excerpts
5637                            .iter()
5638                            .map(|id| excerpt_ids.iter().position(|i| i == id).unwrap())
5639                            .collect::<Vec<_>>();
5640                        log::info!("Expanding excerpts {excerpt_ixs:?} by {line_count} lines");
5641                        multibuffer.expand_excerpts(
5642                            excerpts.iter().cloned(),
5643                            line_count,
5644                            ExpandExcerptDirection::UpAndDown,
5645                            cx,
5646                        );
5647
5648                        if line_count > 0 {
5649                            for id in excerpts {
5650                                let excerpt_ix = excerpt_ids.iter().position(|&i| i == id).unwrap();
5651                                let (buffer, range) = &mut expected_excerpts[excerpt_ix];
5652                                let snapshot = buffer.read(cx).snapshot();
5653                                let mut point_range = range.to_point(&snapshot);
5654                                point_range.start =
5655                                    Point::new(point_range.start.row.saturating_sub(line_count), 0);
5656                                point_range.end = snapshot.clip_point(
5657                                    Point::new(point_range.end.row + line_count, 0),
5658                                    Bias::Left,
5659                                );
5660                                point_range.end.column = snapshot.line_len(point_range.end.row);
5661                                *range = snapshot.anchor_before(point_range.start)
5662                                    ..snapshot.anchor_after(point_range.end);
5663                            }
5664                        }
5665                    });
5666                }
5667                20..=29 if !expected_excerpts.is_empty() => {
5668                    let mut ids_to_remove = vec![];
5669                    for _ in 0..rng.gen_range(1..=3) {
5670                        if expected_excerpts.is_empty() {
5671                            break;
5672                        }
5673
5674                        let ix = rng.gen_range(0..expected_excerpts.len());
5675                        ids_to_remove.push(excerpt_ids.remove(ix));
5676                        let (buffer, range) = expected_excerpts.remove(ix);
5677                        let buffer = buffer.read(cx);
5678                        log::info!(
5679                            "Removing excerpt {}: {:?}",
5680                            ix,
5681                            buffer
5682                                .text_for_range(range.to_offset(buffer))
5683                                .collect::<String>(),
5684                        );
5685                    }
5686                    let snapshot = multibuffer.read(cx).read(cx);
5687                    ids_to_remove.sort_unstable_by(|a, b| a.cmp(&b, &snapshot));
5688                    drop(snapshot);
5689                    multibuffer.update(cx, |multibuffer, cx| {
5690                        multibuffer.remove_excerpts(ids_to_remove, cx)
5691                    });
5692                }
5693                30..=39 if !expected_excerpts.is_empty() => {
5694                    let multibuffer = multibuffer.read(cx).read(cx);
5695                    let offset =
5696                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
5697                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
5698                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
5699                    anchors.push(multibuffer.anchor_at(offset, bias));
5700                    anchors.sort_by(|a, b| a.cmp(b, &multibuffer));
5701                }
5702                40..=44 if !anchors.is_empty() => {
5703                    let multibuffer = multibuffer.read(cx).read(cx);
5704                    let prev_len = anchors.len();
5705                    anchors = multibuffer
5706                        .refresh_anchors(&anchors)
5707                        .into_iter()
5708                        .map(|a| a.1)
5709                        .collect();
5710
5711                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
5712                    // overshoot its boundaries.
5713                    assert_eq!(anchors.len(), prev_len);
5714                    for anchor in &anchors {
5715                        if anchor.excerpt_id == ExcerptId::min()
5716                            || anchor.excerpt_id == ExcerptId::max()
5717                        {
5718                            continue;
5719                        }
5720
5721                        let excerpt = multibuffer.excerpt(anchor.excerpt_id).unwrap();
5722                        assert_eq!(excerpt.id, anchor.excerpt_id);
5723                        assert!(excerpt.contains(anchor));
5724                    }
5725                }
5726                _ => {
5727                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
5728                        let base_text = util::RandomCharIter::new(&mut rng)
5729                            .take(25)
5730                            .collect::<String>();
5731
5732                        buffers.push(cx.new_model(|cx| Buffer::local(base_text, cx)));
5733                        buffers.last().unwrap()
5734                    } else {
5735                        buffers.choose(&mut rng).unwrap()
5736                    };
5737
5738                    let buffer = buffer_handle.read(cx);
5739                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
5740                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5741                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
5742                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
5743                    let prev_excerpt_id = excerpt_ids
5744                        .get(prev_excerpt_ix)
5745                        .cloned()
5746                        .unwrap_or_else(ExcerptId::max);
5747                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
5748
5749                    log::info!(
5750                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
5751                        excerpt_ix,
5752                        expected_excerpts.len(),
5753                        buffer_handle.read(cx).remote_id(),
5754                        buffer.text(),
5755                        start_ix..end_ix,
5756                        &buffer.text()[start_ix..end_ix]
5757                    );
5758
5759                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
5760                        multibuffer
5761                            .insert_excerpts_after(
5762                                prev_excerpt_id,
5763                                buffer_handle.clone(),
5764                                [ExcerptRange {
5765                                    context: start_ix..end_ix,
5766                                    primary: None,
5767                                }],
5768                                cx,
5769                            )
5770                            .pop()
5771                            .unwrap()
5772                    });
5773
5774                    excerpt_ids.insert(excerpt_ix, excerpt_id);
5775                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
5776                }
5777            }
5778
5779            if rng.gen_bool(0.3) {
5780                multibuffer.update(cx, |multibuffer, cx| {
5781                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
5782                })
5783            }
5784
5785            let snapshot = multibuffer.read(cx).snapshot(cx);
5786
5787            let mut excerpt_starts = Vec::new();
5788            let mut expected_text = String::new();
5789            let mut expected_buffer_rows = Vec::new();
5790            for (buffer, range) in &expected_excerpts {
5791                let buffer = buffer.read(cx);
5792                let buffer_range = range.to_offset(buffer);
5793
5794                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
5795                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
5796                expected_text.push('\n');
5797
5798                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
5799                    ..=buffer.offset_to_point(buffer_range.end).row;
5800                for row in buffer_row_range {
5801                    expected_buffer_rows.push(Some(row));
5802                }
5803            }
5804            // Remove final trailing newline.
5805            if !expected_excerpts.is_empty() {
5806                expected_text.pop();
5807            }
5808
5809            // Always report one buffer row
5810            if expected_buffer_rows.is_empty() {
5811                expected_buffer_rows.push(Some(0));
5812            }
5813
5814            assert_eq!(snapshot.text(), expected_text);
5815            log::info!("MultiBuffer text: {:?}", expected_text);
5816
5817            assert_eq!(
5818                snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
5819                expected_buffer_rows,
5820            );
5821
5822            for _ in 0..5 {
5823                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
5824                assert_eq!(
5825                    snapshot
5826                        .buffer_rows(MultiBufferRow(start_row as u32))
5827                        .collect::<Vec<_>>(),
5828                    &expected_buffer_rows[start_row..],
5829                    "buffer_rows({})",
5830                    start_row
5831                );
5832            }
5833
5834            assert_eq!(
5835                snapshot.max_buffer_row().0,
5836                expected_buffer_rows.into_iter().flatten().max().unwrap()
5837            );
5838
5839            let mut excerpt_starts = excerpt_starts.into_iter();
5840            for (buffer, range) in &expected_excerpts {
5841                let buffer = buffer.read(cx);
5842                let buffer_id = buffer.remote_id();
5843                let buffer_range = range.to_offset(buffer);
5844                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
5845                let buffer_start_point_utf16 =
5846                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
5847
5848                let excerpt_start = excerpt_starts.next().unwrap();
5849                let mut offset = excerpt_start.len;
5850                let mut buffer_offset = buffer_range.start;
5851                let mut point = excerpt_start.lines;
5852                let mut buffer_point = buffer_start_point;
5853                let mut point_utf16 = excerpt_start.lines_utf16();
5854                let mut buffer_point_utf16 = buffer_start_point_utf16;
5855                for ch in buffer
5856                    .snapshot()
5857                    .chunks(buffer_range.clone(), false)
5858                    .flat_map(|c| c.text.chars())
5859                {
5860                    for _ in 0..ch.len_utf8() {
5861                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
5862                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
5863                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
5864                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
5865                        assert_eq!(
5866                            left_offset,
5867                            excerpt_start.len + (buffer_left_offset - buffer_range.start),
5868                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
5869                            offset,
5870                            buffer_id,
5871                            buffer_offset,
5872                        );
5873                        assert_eq!(
5874                            right_offset,
5875                            excerpt_start.len + (buffer_right_offset - buffer_range.start),
5876                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
5877                            offset,
5878                            buffer_id,
5879                            buffer_offset,
5880                        );
5881
5882                        let left_point = snapshot.clip_point(point, Bias::Left);
5883                        let right_point = snapshot.clip_point(point, Bias::Right);
5884                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
5885                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
5886                        assert_eq!(
5887                            left_point,
5888                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
5889                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
5890                            point,
5891                            buffer_id,
5892                            buffer_point,
5893                        );
5894                        assert_eq!(
5895                            right_point,
5896                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
5897                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
5898                            point,
5899                            buffer_id,
5900                            buffer_point,
5901                        );
5902
5903                        assert_eq!(
5904                            snapshot.point_to_offset(left_point),
5905                            left_offset,
5906                            "point_to_offset({:?})",
5907                            left_point,
5908                        );
5909                        assert_eq!(
5910                            snapshot.offset_to_point(left_offset),
5911                            left_point,
5912                            "offset_to_point({:?})",
5913                            left_offset,
5914                        );
5915
5916                        offset += 1;
5917                        buffer_offset += 1;
5918                        if ch == '\n' {
5919                            point += Point::new(1, 0);
5920                            buffer_point += Point::new(1, 0);
5921                        } else {
5922                            point += Point::new(0, 1);
5923                            buffer_point += Point::new(0, 1);
5924                        }
5925                    }
5926
5927                    for _ in 0..ch.len_utf16() {
5928                        let left_point_utf16 =
5929                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Left);
5930                        let right_point_utf16 =
5931                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Right);
5932                        let buffer_left_point_utf16 =
5933                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Left);
5934                        let buffer_right_point_utf16 =
5935                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Right);
5936                        assert_eq!(
5937                            left_point_utf16,
5938                            excerpt_start.lines_utf16()
5939                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
5940                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
5941                            point_utf16,
5942                            buffer_id,
5943                            buffer_point_utf16,
5944                        );
5945                        assert_eq!(
5946                            right_point_utf16,
5947                            excerpt_start.lines_utf16()
5948                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
5949                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
5950                            point_utf16,
5951                            buffer_id,
5952                            buffer_point_utf16,
5953                        );
5954
5955                        if ch == '\n' {
5956                            point_utf16 += PointUtf16::new(1, 0);
5957                            buffer_point_utf16 += PointUtf16::new(1, 0);
5958                        } else {
5959                            point_utf16 += PointUtf16::new(0, 1);
5960                            buffer_point_utf16 += PointUtf16::new(0, 1);
5961                        }
5962                    }
5963                }
5964            }
5965
5966            for (row, line) in expected_text.split('\n').enumerate() {
5967                assert_eq!(
5968                    snapshot.line_len(MultiBufferRow(row as u32)),
5969                    line.len() as u32,
5970                    "line_len({}).",
5971                    row
5972                );
5973            }
5974
5975            let text_rope = Rope::from(expected_text.as_str());
5976            for _ in 0..10 {
5977                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5978                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5979
5980                let text_for_range = snapshot
5981                    .text_for_range(start_ix..end_ix)
5982                    .collect::<String>();
5983                assert_eq!(
5984                    text_for_range,
5985                    &expected_text[start_ix..end_ix],
5986                    "incorrect text for range {:?}",
5987                    start_ix..end_ix
5988                );
5989
5990                let excerpted_buffer_ranges = multibuffer
5991                    .read(cx)
5992                    .range_to_buffer_ranges(start_ix..end_ix, cx);
5993                let excerpted_buffers_text = excerpted_buffer_ranges
5994                    .iter()
5995                    .map(|(buffer, buffer_range, _)| {
5996                        buffer
5997                            .read(cx)
5998                            .text_for_range(buffer_range.clone())
5999                            .collect::<String>()
6000                    })
6001                    .collect::<Vec<_>>()
6002                    .join("\n");
6003                assert_eq!(excerpted_buffers_text, text_for_range);
6004                if !expected_excerpts.is_empty() {
6005                    assert!(!excerpted_buffer_ranges.is_empty());
6006                }
6007
6008                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
6009                assert_eq!(
6010                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
6011                    expected_summary,
6012                    "incorrect summary for range {:?}",
6013                    start_ix..end_ix
6014                );
6015            }
6016
6017            // Anchor resolution
6018            let summaries = snapshot.summaries_for_anchors::<usize, _>(&anchors);
6019            assert_eq!(anchors.len(), summaries.len());
6020            for (anchor, resolved_offset) in anchors.iter().zip(summaries) {
6021                assert!(resolved_offset <= snapshot.len());
6022                assert_eq!(
6023                    snapshot.summary_for_anchor::<usize>(anchor),
6024                    resolved_offset
6025                );
6026            }
6027
6028            for _ in 0..10 {
6029                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
6030                assert_eq!(
6031                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
6032                    expected_text[..end_ix].chars().rev().collect::<String>(),
6033                );
6034            }
6035
6036            for _ in 0..10 {
6037                let end_ix = rng.gen_range(0..=text_rope.len());
6038                let start_ix = rng.gen_range(0..=end_ix);
6039                assert_eq!(
6040                    snapshot
6041                        .bytes_in_range(start_ix..end_ix)
6042                        .flatten()
6043                        .copied()
6044                        .collect::<Vec<_>>(),
6045                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
6046                    "bytes_in_range({:?})",
6047                    start_ix..end_ix,
6048                );
6049            }
6050        }
6051
6052        let snapshot = multibuffer.read(cx).snapshot(cx);
6053        for (old_snapshot, subscription) in old_versions {
6054            let edits = subscription.consume().into_inner();
6055
6056            log::info!(
6057                "applying subscription edits to old text: {:?}: {:?}",
6058                old_snapshot.text(),
6059                edits,
6060            );
6061
6062            let mut text = old_snapshot.text();
6063            for edit in edits {
6064                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
6065                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
6066            }
6067            assert_eq!(text.to_string(), snapshot.text());
6068        }
6069    }
6070
6071    #[gpui::test]
6072    fn test_history(cx: &mut AppContext) {
6073        let test_settings = SettingsStore::test(cx);
6074        cx.set_global(test_settings);
6075
6076        let buffer_1 = cx.new_model(|cx| Buffer::local("1234", cx));
6077        let buffer_2 = cx.new_model(|cx| Buffer::local("5678", cx));
6078        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6079        let group_interval = multibuffer.read(cx).history.group_interval;
6080        multibuffer.update(cx, |multibuffer, cx| {
6081            multibuffer.push_excerpts(
6082                buffer_1.clone(),
6083                [ExcerptRange {
6084                    context: 0..buffer_1.read(cx).len(),
6085                    primary: None,
6086                }],
6087                cx,
6088            );
6089            multibuffer.push_excerpts(
6090                buffer_2.clone(),
6091                [ExcerptRange {
6092                    context: 0..buffer_2.read(cx).len(),
6093                    primary: None,
6094                }],
6095                cx,
6096            );
6097        });
6098
6099        let mut now = Instant::now();
6100
6101        multibuffer.update(cx, |multibuffer, cx| {
6102            let transaction_1 = multibuffer.start_transaction_at(now, cx).unwrap();
6103            multibuffer.edit(
6104                [
6105                    (Point::new(0, 0)..Point::new(0, 0), "A"),
6106                    (Point::new(1, 0)..Point::new(1, 0), "A"),
6107                ],
6108                None,
6109                cx,
6110            );
6111            multibuffer.edit(
6112                [
6113                    (Point::new(0, 1)..Point::new(0, 1), "B"),
6114                    (Point::new(1, 1)..Point::new(1, 1), "B"),
6115                ],
6116                None,
6117                cx,
6118            );
6119            multibuffer.end_transaction_at(now, cx);
6120            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6121
6122            // Verify edited ranges for transaction 1
6123            assert_eq!(
6124                multibuffer.edited_ranges_for_transaction(transaction_1, cx),
6125                &[
6126                    Point::new(0, 0)..Point::new(0, 2),
6127                    Point::new(1, 0)..Point::new(1, 2)
6128                ]
6129            );
6130
6131            // Edit buffer 1 through the multibuffer
6132            now += 2 * group_interval;
6133            multibuffer.start_transaction_at(now, cx);
6134            multibuffer.edit([(2..2, "C")], None, cx);
6135            multibuffer.end_transaction_at(now, cx);
6136            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
6137
6138            // Edit buffer 1 independently
6139            buffer_1.update(cx, |buffer_1, cx| {
6140                buffer_1.start_transaction_at(now);
6141                buffer_1.edit([(3..3, "D")], None, cx);
6142                buffer_1.end_transaction_at(now, cx);
6143
6144                now += 2 * group_interval;
6145                buffer_1.start_transaction_at(now);
6146                buffer_1.edit([(4..4, "E")], None, cx);
6147                buffer_1.end_transaction_at(now, cx);
6148            });
6149            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
6150
6151            // An undo in the multibuffer undoes the multibuffer transaction
6152            // and also any individual buffer edits that have occurred since
6153            // that transaction.
6154            multibuffer.undo(cx);
6155            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6156
6157            multibuffer.undo(cx);
6158            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6159
6160            multibuffer.redo(cx);
6161            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6162
6163            multibuffer.redo(cx);
6164            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
6165
6166            // Undo buffer 2 independently.
6167            buffer_2.update(cx, |buffer_2, cx| buffer_2.undo(cx));
6168            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\n5678");
6169
6170            // An undo in the multibuffer undoes the components of the
6171            // the last multibuffer transaction that are not already undone.
6172            multibuffer.undo(cx);
6173            assert_eq!(multibuffer.read(cx).text(), "AB1234\n5678");
6174
6175            multibuffer.undo(cx);
6176            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6177
6178            multibuffer.redo(cx);
6179            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6180
6181            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
6182            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
6183
6184            // Redo stack gets cleared after an edit.
6185            now += 2 * group_interval;
6186            multibuffer.start_transaction_at(now, cx);
6187            multibuffer.edit([(0..0, "X")], None, cx);
6188            multibuffer.end_transaction_at(now, cx);
6189            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6190            multibuffer.redo(cx);
6191            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6192            multibuffer.undo(cx);
6193            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
6194            multibuffer.undo(cx);
6195            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6196
6197            // Transactions can be grouped manually.
6198            multibuffer.redo(cx);
6199            multibuffer.redo(cx);
6200            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6201            multibuffer.group_until_transaction(transaction_1, cx);
6202            multibuffer.undo(cx);
6203            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6204            multibuffer.redo(cx);
6205            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6206        });
6207    }
6208
6209    #[gpui::test]
6210    fn test_excerpts_in_ranges_no_ranges(cx: &mut AppContext) {
6211        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6212        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6213        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6214        multibuffer.update(cx, |multibuffer, cx| {
6215            multibuffer.push_excerpts(
6216                buffer_1.clone(),
6217                [ExcerptRange {
6218                    context: 0..buffer_1.read(cx).len(),
6219                    primary: None,
6220                }],
6221                cx,
6222            );
6223            multibuffer.push_excerpts(
6224                buffer_2.clone(),
6225                [ExcerptRange {
6226                    context: 0..buffer_2.read(cx).len(),
6227                    primary: None,
6228                }],
6229                cx,
6230            );
6231        });
6232
6233        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
6234
6235        let mut excerpts = snapshot.excerpts_in_ranges(iter::from_fn(|| None));
6236
6237        assert!(excerpts.next().is_none());
6238    }
6239
6240    fn validate_excerpts(
6241        actual: &Vec<(ExcerptId, BufferId, Range<Anchor>)>,
6242        expected: &Vec<(ExcerptId, BufferId, Range<Anchor>)>,
6243    ) {
6244        assert_eq!(actual.len(), expected.len());
6245
6246        actual
6247            .into_iter()
6248            .zip(expected)
6249            .map(|(actual, expected)| {
6250                assert_eq!(actual.0, expected.0);
6251                assert_eq!(actual.1, expected.1);
6252                assert_eq!(actual.2.start, expected.2.start);
6253                assert_eq!(actual.2.end, expected.2.end);
6254            })
6255            .collect_vec();
6256    }
6257
6258    fn map_range_from_excerpt(
6259        snapshot: &MultiBufferSnapshot,
6260        excerpt_id: ExcerptId,
6261        excerpt_buffer: &BufferSnapshot,
6262        range: Range<usize>,
6263    ) -> Range<Anchor> {
6264        snapshot
6265            .anchor_in_excerpt(excerpt_id, excerpt_buffer.anchor_before(range.start))
6266            .unwrap()
6267            ..snapshot
6268                .anchor_in_excerpt(excerpt_id, excerpt_buffer.anchor_after(range.end))
6269                .unwrap()
6270    }
6271
6272    fn make_expected_excerpt_info(
6273        snapshot: &MultiBufferSnapshot,
6274        cx: &mut AppContext,
6275        excerpt_id: ExcerptId,
6276        buffer: &Model<Buffer>,
6277        range: Range<usize>,
6278    ) -> (ExcerptId, BufferId, Range<Anchor>) {
6279        (
6280            excerpt_id,
6281            buffer.read(cx).remote_id(),
6282            map_range_from_excerpt(&snapshot, excerpt_id, &buffer.read(cx).snapshot(), range),
6283        )
6284    }
6285
6286    #[gpui::test]
6287    fn test_excerpts_in_ranges_range_inside_the_excerpt(cx: &mut AppContext) {
6288        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6289        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6290        let buffer_len = buffer_1.read(cx).len();
6291        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6292        let mut expected_excerpt_id = ExcerptId(0);
6293
6294        multibuffer.update(cx, |multibuffer, cx| {
6295            expected_excerpt_id = multibuffer.push_excerpts(
6296                buffer_1.clone(),
6297                [ExcerptRange {
6298                    context: 0..buffer_1.read(cx).len(),
6299                    primary: None,
6300                }],
6301                cx,
6302            )[0];
6303            multibuffer.push_excerpts(
6304                buffer_2.clone(),
6305                [ExcerptRange {
6306                    context: 0..buffer_2.read(cx).len(),
6307                    primary: None,
6308                }],
6309                cx,
6310            );
6311        });
6312
6313        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
6314
6315        let range = snapshot
6316            .anchor_in_excerpt(expected_excerpt_id, buffer_1.read(cx).anchor_before(1))
6317            .unwrap()
6318            ..snapshot
6319                .anchor_in_excerpt(
6320                    expected_excerpt_id,
6321                    buffer_1.read(cx).anchor_after(buffer_len / 2),
6322                )
6323                .unwrap();
6324
6325        let expected_excerpts = vec![make_expected_excerpt_info(
6326            &snapshot,
6327            cx,
6328            expected_excerpt_id,
6329            &buffer_1,
6330            1..(buffer_len / 2),
6331        )];
6332
6333        let excerpts = snapshot
6334            .excerpts_in_ranges(vec![range.clone()].into_iter())
6335            .map(|(excerpt_id, buffer, actual_range)| {
6336                (
6337                    excerpt_id,
6338                    buffer.remote_id(),
6339                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6340                )
6341            })
6342            .collect_vec();
6343
6344        validate_excerpts(&excerpts, &expected_excerpts);
6345    }
6346
6347    #[gpui::test]
6348    fn test_excerpts_in_ranges_range_crosses_excerpts_boundary(cx: &mut AppContext) {
6349        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6350        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6351        let buffer_len = buffer_1.read(cx).len();
6352        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6353        let mut excerpt_1_id = ExcerptId(0);
6354        let mut excerpt_2_id = ExcerptId(0);
6355
6356        multibuffer.update(cx, |multibuffer, cx| {
6357            excerpt_1_id = multibuffer.push_excerpts(
6358                buffer_1.clone(),
6359                [ExcerptRange {
6360                    context: 0..buffer_1.read(cx).len(),
6361                    primary: None,
6362                }],
6363                cx,
6364            )[0];
6365            excerpt_2_id = multibuffer.push_excerpts(
6366                buffer_2.clone(),
6367                [ExcerptRange {
6368                    context: 0..buffer_2.read(cx).len(),
6369                    primary: None,
6370                }],
6371                cx,
6372            )[0];
6373        });
6374
6375        let snapshot = multibuffer.read(cx).snapshot(cx);
6376
6377        let expected_range = snapshot
6378            .anchor_in_excerpt(
6379                excerpt_1_id,
6380                buffer_1.read(cx).anchor_before(buffer_len / 2),
6381            )
6382            .unwrap()
6383            ..snapshot
6384                .anchor_in_excerpt(excerpt_2_id, buffer_2.read(cx).anchor_after(buffer_len / 2))
6385                .unwrap();
6386
6387        let expected_excerpts = vec![
6388            make_expected_excerpt_info(
6389                &snapshot,
6390                cx,
6391                excerpt_1_id,
6392                &buffer_1,
6393                (buffer_len / 2)..buffer_len,
6394            ),
6395            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, 0..buffer_len / 2),
6396        ];
6397
6398        let excerpts = snapshot
6399            .excerpts_in_ranges(vec![expected_range.clone()].into_iter())
6400            .map(|(excerpt_id, buffer, actual_range)| {
6401                (
6402                    excerpt_id,
6403                    buffer.remote_id(),
6404                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6405                )
6406            })
6407            .collect_vec();
6408
6409        validate_excerpts(&excerpts, &expected_excerpts);
6410    }
6411
6412    #[gpui::test]
6413    fn test_excerpts_in_ranges_range_encloses_excerpt(cx: &mut AppContext) {
6414        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6415        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6416        let buffer_3 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'r'), cx));
6417        let buffer_len = buffer_1.read(cx).len();
6418        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6419        let mut excerpt_1_id = ExcerptId(0);
6420        let mut excerpt_2_id = ExcerptId(0);
6421        let mut excerpt_3_id = ExcerptId(0);
6422
6423        multibuffer.update(cx, |multibuffer, cx| {
6424            excerpt_1_id = multibuffer.push_excerpts(
6425                buffer_1.clone(),
6426                [ExcerptRange {
6427                    context: 0..buffer_1.read(cx).len(),
6428                    primary: None,
6429                }],
6430                cx,
6431            )[0];
6432            excerpt_2_id = multibuffer.push_excerpts(
6433                buffer_2.clone(),
6434                [ExcerptRange {
6435                    context: 0..buffer_2.read(cx).len(),
6436                    primary: None,
6437                }],
6438                cx,
6439            )[0];
6440            excerpt_3_id = multibuffer.push_excerpts(
6441                buffer_3.clone(),
6442                [ExcerptRange {
6443                    context: 0..buffer_3.read(cx).len(),
6444                    primary: None,
6445                }],
6446                cx,
6447            )[0];
6448        });
6449
6450        let snapshot = multibuffer.read(cx).snapshot(cx);
6451
6452        let expected_range = snapshot
6453            .anchor_in_excerpt(
6454                excerpt_1_id,
6455                buffer_1.read(cx).anchor_before(buffer_len / 2),
6456            )
6457            .unwrap()
6458            ..snapshot
6459                .anchor_in_excerpt(excerpt_3_id, buffer_3.read(cx).anchor_after(buffer_len / 2))
6460                .unwrap();
6461
6462        let expected_excerpts = vec![
6463            make_expected_excerpt_info(
6464                &snapshot,
6465                cx,
6466                excerpt_1_id,
6467                &buffer_1,
6468                (buffer_len / 2)..buffer_len,
6469            ),
6470            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, 0..buffer_len),
6471            make_expected_excerpt_info(&snapshot, cx, excerpt_3_id, &buffer_3, 0..buffer_len / 2),
6472        ];
6473
6474        let excerpts = snapshot
6475            .excerpts_in_ranges(vec![expected_range.clone()].into_iter())
6476            .map(|(excerpt_id, buffer, actual_range)| {
6477                (
6478                    excerpt_id,
6479                    buffer.remote_id(),
6480                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6481                )
6482            })
6483            .collect_vec();
6484
6485        validate_excerpts(&excerpts, &expected_excerpts);
6486    }
6487
6488    #[gpui::test]
6489    fn test_excerpts_in_ranges_multiple_ranges(cx: &mut AppContext) {
6490        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6491        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6492        let buffer_len = buffer_1.read(cx).len();
6493        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6494        let mut excerpt_1_id = ExcerptId(0);
6495        let mut excerpt_2_id = ExcerptId(0);
6496
6497        multibuffer.update(cx, |multibuffer, cx| {
6498            excerpt_1_id = multibuffer.push_excerpts(
6499                buffer_1.clone(),
6500                [ExcerptRange {
6501                    context: 0..buffer_1.read(cx).len(),
6502                    primary: None,
6503                }],
6504                cx,
6505            )[0];
6506            excerpt_2_id = multibuffer.push_excerpts(
6507                buffer_2.clone(),
6508                [ExcerptRange {
6509                    context: 0..buffer_2.read(cx).len(),
6510                    primary: None,
6511                }],
6512                cx,
6513            )[0];
6514        });
6515
6516        let snapshot = multibuffer.read(cx).snapshot(cx);
6517
6518        let ranges = vec![
6519            1..(buffer_len / 4),
6520            (buffer_len / 3)..(buffer_len / 2),
6521            (buffer_len / 4 * 3)..(buffer_len),
6522        ];
6523
6524        let expected_excerpts = ranges
6525            .iter()
6526            .map(|range| {
6527                make_expected_excerpt_info(&snapshot, cx, excerpt_1_id, &buffer_1, range.clone())
6528            })
6529            .collect_vec();
6530
6531        let ranges = ranges.into_iter().map(|range| {
6532            map_range_from_excerpt(
6533                &snapshot,
6534                excerpt_1_id,
6535                &buffer_1.read(cx).snapshot(),
6536                range,
6537            )
6538        });
6539
6540        let excerpts = snapshot
6541            .excerpts_in_ranges(ranges)
6542            .map(|(excerpt_id, buffer, actual_range)| {
6543                (
6544                    excerpt_id,
6545                    buffer.remote_id(),
6546                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6547                )
6548            })
6549            .collect_vec();
6550
6551        validate_excerpts(&excerpts, &expected_excerpts);
6552    }
6553
6554    #[gpui::test]
6555    fn test_excerpts_in_ranges_range_ends_at_excerpt_end(cx: &mut AppContext) {
6556        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6557        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6558        let buffer_len = buffer_1.read(cx).len();
6559        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6560        let mut excerpt_1_id = ExcerptId(0);
6561        let mut excerpt_2_id = ExcerptId(0);
6562
6563        multibuffer.update(cx, |multibuffer, cx| {
6564            excerpt_1_id = multibuffer.push_excerpts(
6565                buffer_1.clone(),
6566                [ExcerptRange {
6567                    context: 0..buffer_1.read(cx).len(),
6568                    primary: None,
6569                }],
6570                cx,
6571            )[0];
6572            excerpt_2_id = multibuffer.push_excerpts(
6573                buffer_2.clone(),
6574                [ExcerptRange {
6575                    context: 0..buffer_2.read(cx).len(),
6576                    primary: None,
6577                }],
6578                cx,
6579            )[0];
6580        });
6581
6582        let snapshot = multibuffer.read(cx).snapshot(cx);
6583
6584        let ranges = [0..buffer_len, (buffer_len / 3)..(buffer_len / 2)];
6585
6586        let expected_excerpts = vec![
6587            make_expected_excerpt_info(&snapshot, cx, excerpt_1_id, &buffer_1, ranges[0].clone()),
6588            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, ranges[1].clone()),
6589        ];
6590
6591        let ranges = [
6592            map_range_from_excerpt(
6593                &snapshot,
6594                excerpt_1_id,
6595                &buffer_1.read(cx).snapshot(),
6596                ranges[0].clone(),
6597            ),
6598            map_range_from_excerpt(
6599                &snapshot,
6600                excerpt_2_id,
6601                &buffer_2.read(cx).snapshot(),
6602                ranges[1].clone(),
6603            ),
6604        ];
6605
6606        let excerpts = snapshot
6607            .excerpts_in_ranges(ranges.into_iter())
6608            .map(|(excerpt_id, buffer, actual_range)| {
6609                (
6610                    excerpt_id,
6611                    buffer.remote_id(),
6612                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6613                )
6614            })
6615            .collect_vec();
6616
6617        validate_excerpts(&excerpts, &expected_excerpts);
6618    }
6619}