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