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                    })
3643                })
3644                .collect(),
3645        ))
3646    }
3647
3648    pub fn symbols_containing<T: ToOffset>(
3649        &self,
3650        offset: T,
3651        theme: Option<&SyntaxTheme>,
3652    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
3653        let anchor = self.anchor_before(offset);
3654        let excerpt_id = anchor.excerpt_id;
3655        let excerpt = self.excerpt(excerpt_id)?;
3656        Some((
3657            excerpt.buffer_id,
3658            excerpt
3659                .buffer
3660                .symbols_containing(anchor.text_anchor, theme)
3661                .into_iter()
3662                .flatten()
3663                .flat_map(|item| {
3664                    Some(OutlineItem {
3665                        depth: item.depth,
3666                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
3667                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
3668                        text: item.text,
3669                        highlight_ranges: item.highlight_ranges,
3670                        name_ranges: item.name_ranges,
3671                    })
3672                })
3673                .collect(),
3674        ))
3675    }
3676
3677    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
3678        if id == ExcerptId::min() {
3679            Locator::min_ref()
3680        } else if id == ExcerptId::max() {
3681            Locator::max_ref()
3682        } else {
3683            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3684            cursor.seek(&id, Bias::Left, &());
3685            if let Some(entry) = cursor.item() {
3686                if entry.id == id {
3687                    return &entry.locator;
3688                }
3689            }
3690            panic!("invalid excerpt id {:?}", id)
3691        }
3692    }
3693
3694    // Returns the locators referenced by the given excerpt ids, sorted by locator.
3695    fn excerpt_locators_for_ids(
3696        &self,
3697        ids: impl IntoIterator<Item = ExcerptId>,
3698    ) -> SmallVec<[Locator; 1]> {
3699        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
3700        sorted_ids.sort_unstable();
3701        let mut locators = SmallVec::new();
3702
3703        while sorted_ids.last() == Some(&ExcerptId::max()) {
3704            sorted_ids.pop();
3705            locators.push(Locator::max());
3706        }
3707
3708        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
3709        if sorted_ids.peek() == Some(&ExcerptId::min()) {
3710            sorted_ids.next();
3711            locators.push(Locator::min());
3712        }
3713
3714        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3715        for id in sorted_ids {
3716            if cursor.seek_forward(&id, Bias::Left, &()) {
3717                locators.push(cursor.item().unwrap().locator.clone());
3718            } else {
3719                panic!("invalid excerpt id {:?}", id);
3720            }
3721        }
3722
3723        locators.sort_unstable();
3724        locators
3725    }
3726
3727    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
3728        Some(self.excerpt(excerpt_id)?.buffer_id)
3729    }
3730
3731    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
3732        Some(&self.excerpt(excerpt_id)?.buffer)
3733    }
3734
3735    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
3736        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
3737        let locator = self.excerpt_locator_for_id(excerpt_id);
3738        cursor.seek(&Some(locator), Bias::Left, &());
3739        if let Some(excerpt) = cursor.item() {
3740            if excerpt.id == excerpt_id {
3741                return Some(excerpt);
3742            }
3743        }
3744        None
3745    }
3746
3747    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
3748    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
3749        let range = range.start.to_offset(self)..range.end.to_offset(self);
3750
3751        let mut cursor = self.excerpts.cursor::<usize>();
3752        cursor.seek(&range.start, Bias::Right, &());
3753        let start_excerpt = cursor.item()?;
3754
3755        if range.start == range.end {
3756            return Some(MultiBufferExcerpt::new(start_excerpt, *cursor.start()));
3757        }
3758
3759        cursor.seek(&range.end, Bias::Right, &());
3760        let end_excerpt = cursor.item()?;
3761
3762        if start_excerpt.id == end_excerpt.id {
3763            Some(MultiBufferExcerpt::new(start_excerpt, *cursor.start()))
3764        } else {
3765            None
3766        }
3767    }
3768
3769    /// Returns excerpts overlapping the given ranges. If range spans multiple excerpts returns one range for each excerpt
3770    pub fn excerpts_in_ranges(
3771        &self,
3772        ranges: impl IntoIterator<Item = Range<Anchor>>,
3773    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, Range<usize>)> {
3774        let mut ranges = ranges.into_iter().map(|range| range.to_offset(self));
3775        let mut cursor = self.excerpts.cursor::<usize>();
3776        cursor.next(&());
3777        let mut current_range = ranges.next();
3778        iter::from_fn(move || {
3779            let range = current_range.clone()?;
3780            if range.start >= cursor.end(&()) {
3781                cursor.seek_forward(&range.start, Bias::Right, &());
3782                if range.start == self.len() {
3783                    cursor.prev(&());
3784                }
3785            }
3786
3787            let excerpt = cursor.item()?;
3788            let range_start_in_excerpt = cmp::max(range.start, *cursor.start());
3789            let range_end_in_excerpt = if excerpt.has_trailing_newline {
3790                cmp::min(range.end, cursor.end(&()) - 1)
3791            } else {
3792                cmp::min(range.end, cursor.end(&()))
3793            };
3794            let buffer_range = MultiBufferExcerpt::new(excerpt, *cursor.start())
3795                .map_range_to_buffer(range_start_in_excerpt..range_end_in_excerpt);
3796
3797            if range.end > cursor.end(&()) {
3798                cursor.next(&());
3799            } else {
3800                current_range = ranges.next();
3801            }
3802
3803            Some((excerpt.id, &excerpt.buffer, buffer_range))
3804        })
3805    }
3806
3807    pub fn selections_in_range<'a>(
3808        &'a self,
3809        range: &'a Range<Anchor>,
3810        include_local: bool,
3811    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
3812        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
3813        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
3814        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
3815        cursor.seek(start_locator, Bias::Left, &());
3816        cursor
3817            .take_while(move |excerpt| excerpt.locator <= *end_locator)
3818            .flat_map(move |excerpt| {
3819                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
3820                if excerpt.id == range.start.excerpt_id {
3821                    query_range.start = range.start.text_anchor;
3822                }
3823                if excerpt.id == range.end.excerpt_id {
3824                    query_range.end = range.end.text_anchor;
3825                }
3826
3827                excerpt
3828                    .buffer
3829                    .selections_in_range(query_range, include_local)
3830                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
3831                        selections.map(move |selection| {
3832                            let mut start = Anchor {
3833                                buffer_id: Some(excerpt.buffer_id),
3834                                excerpt_id: excerpt.id,
3835                                text_anchor: selection.start,
3836                            };
3837                            let mut end = Anchor {
3838                                buffer_id: Some(excerpt.buffer_id),
3839                                excerpt_id: excerpt.id,
3840                                text_anchor: selection.end,
3841                            };
3842                            if range.start.cmp(&start, self).is_gt() {
3843                                start = range.start;
3844                            }
3845                            if range.end.cmp(&end, self).is_lt() {
3846                                end = range.end;
3847                            }
3848
3849                            (
3850                                replica_id,
3851                                line_mode,
3852                                cursor_shape,
3853                                Selection {
3854                                    id: selection.id,
3855                                    start,
3856                                    end,
3857                                    reversed: selection.reversed,
3858                                    goal: selection.goal,
3859                                },
3860                            )
3861                        })
3862                    })
3863            })
3864    }
3865
3866    pub fn show_headers(&self) -> bool {
3867        self.show_headers
3868    }
3869}
3870
3871#[cfg(any(test, feature = "test-support"))]
3872impl MultiBufferSnapshot {
3873    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
3874        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
3875        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
3876        start..end
3877    }
3878}
3879
3880impl History {
3881    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
3882        self.transaction_depth += 1;
3883        if self.transaction_depth == 1 {
3884            let id = self.next_transaction_id.tick();
3885            self.undo_stack.push(Transaction {
3886                id,
3887                buffer_transactions: Default::default(),
3888                first_edit_at: now,
3889                last_edit_at: now,
3890                suppress_grouping: false,
3891            });
3892            Some(id)
3893        } else {
3894            None
3895        }
3896    }
3897
3898    fn end_transaction(
3899        &mut self,
3900        now: Instant,
3901        buffer_transactions: HashMap<BufferId, TransactionId>,
3902    ) -> bool {
3903        assert_ne!(self.transaction_depth, 0);
3904        self.transaction_depth -= 1;
3905        if self.transaction_depth == 0 {
3906            if buffer_transactions.is_empty() {
3907                self.undo_stack.pop();
3908                false
3909            } else {
3910                self.redo_stack.clear();
3911                let transaction = self.undo_stack.last_mut().unwrap();
3912                transaction.last_edit_at = now;
3913                for (buffer_id, transaction_id) in buffer_transactions {
3914                    transaction
3915                        .buffer_transactions
3916                        .entry(buffer_id)
3917                        .or_insert(transaction_id);
3918                }
3919                true
3920            }
3921        } else {
3922            false
3923        }
3924    }
3925
3926    fn push_transaction<'a, T>(
3927        &mut self,
3928        buffer_transactions: T,
3929        now: Instant,
3930        cx: &mut ModelContext<MultiBuffer>,
3931    ) where
3932        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
3933    {
3934        assert_eq!(self.transaction_depth, 0);
3935        let transaction = Transaction {
3936            id: self.next_transaction_id.tick(),
3937            buffer_transactions: buffer_transactions
3938                .into_iter()
3939                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
3940                .collect(),
3941            first_edit_at: now,
3942            last_edit_at: now,
3943            suppress_grouping: false,
3944        };
3945        if !transaction.buffer_transactions.is_empty() {
3946            self.undo_stack.push(transaction);
3947            self.redo_stack.clear();
3948        }
3949    }
3950
3951    fn finalize_last_transaction(&mut self) {
3952        if let Some(transaction) = self.undo_stack.last_mut() {
3953            transaction.suppress_grouping = true;
3954        }
3955    }
3956
3957    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
3958        if let Some(ix) = self
3959            .undo_stack
3960            .iter()
3961            .rposition(|transaction| transaction.id == transaction_id)
3962        {
3963            Some(self.undo_stack.remove(ix))
3964        } else if let Some(ix) = self
3965            .redo_stack
3966            .iter()
3967            .rposition(|transaction| transaction.id == transaction_id)
3968        {
3969            Some(self.redo_stack.remove(ix))
3970        } else {
3971            None
3972        }
3973    }
3974
3975    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
3976        self.undo_stack
3977            .iter()
3978            .find(|transaction| transaction.id == transaction_id)
3979            .or_else(|| {
3980                self.redo_stack
3981                    .iter()
3982                    .find(|transaction| transaction.id == transaction_id)
3983            })
3984    }
3985
3986    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
3987        self.undo_stack
3988            .iter_mut()
3989            .find(|transaction| transaction.id == transaction_id)
3990            .or_else(|| {
3991                self.redo_stack
3992                    .iter_mut()
3993                    .find(|transaction| transaction.id == transaction_id)
3994            })
3995    }
3996
3997    fn pop_undo(&mut self) -> Option<&mut Transaction> {
3998        assert_eq!(self.transaction_depth, 0);
3999        if let Some(transaction) = self.undo_stack.pop() {
4000            self.redo_stack.push(transaction);
4001            self.redo_stack.last_mut()
4002        } else {
4003            None
4004        }
4005    }
4006
4007    fn pop_redo(&mut self) -> Option<&mut Transaction> {
4008        assert_eq!(self.transaction_depth, 0);
4009        if let Some(transaction) = self.redo_stack.pop() {
4010            self.undo_stack.push(transaction);
4011            self.undo_stack.last_mut()
4012        } else {
4013            None
4014        }
4015    }
4016
4017    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
4018        let ix = self
4019            .undo_stack
4020            .iter()
4021            .rposition(|transaction| transaction.id == transaction_id)?;
4022        let transaction = self.undo_stack.remove(ix);
4023        self.redo_stack.push(transaction);
4024        self.redo_stack.last()
4025    }
4026
4027    fn group(&mut self) -> Option<TransactionId> {
4028        let mut count = 0;
4029        let mut transactions = self.undo_stack.iter();
4030        if let Some(mut transaction) = transactions.next_back() {
4031            while let Some(prev_transaction) = transactions.next_back() {
4032                if !prev_transaction.suppress_grouping
4033                    && transaction.first_edit_at - prev_transaction.last_edit_at
4034                        <= self.group_interval
4035                {
4036                    transaction = prev_transaction;
4037                    count += 1;
4038                } else {
4039                    break;
4040                }
4041            }
4042        }
4043        self.group_trailing(count)
4044    }
4045
4046    fn group_until(&mut self, transaction_id: TransactionId) {
4047        let mut count = 0;
4048        for transaction in self.undo_stack.iter().rev() {
4049            if transaction.id == transaction_id {
4050                self.group_trailing(count);
4051                break;
4052            } else if transaction.suppress_grouping {
4053                break;
4054            } else {
4055                count += 1;
4056            }
4057        }
4058    }
4059
4060    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
4061        let new_len = self.undo_stack.len() - n;
4062        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
4063        if let Some(last_transaction) = transactions_to_keep.last_mut() {
4064            if let Some(transaction) = transactions_to_merge.last() {
4065                last_transaction.last_edit_at = transaction.last_edit_at;
4066            }
4067            for to_merge in transactions_to_merge {
4068                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
4069                    last_transaction
4070                        .buffer_transactions
4071                        .entry(*buffer_id)
4072                        .or_insert(*transaction_id);
4073                }
4074            }
4075        }
4076
4077        self.undo_stack.truncate(new_len);
4078        self.undo_stack.last().map(|t| t.id)
4079    }
4080}
4081
4082impl Excerpt {
4083    fn new(
4084        id: ExcerptId,
4085        locator: Locator,
4086        buffer_id: BufferId,
4087        buffer: BufferSnapshot,
4088        range: ExcerptRange<text::Anchor>,
4089        has_trailing_newline: bool,
4090    ) -> Self {
4091        Excerpt {
4092            id,
4093            locator,
4094            max_buffer_row: range.context.end.to_point(&buffer).row,
4095            text_summary: buffer
4096                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
4097            buffer_id,
4098            buffer,
4099            range,
4100            has_trailing_newline,
4101        }
4102    }
4103
4104    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
4105        let content_start = self.range.context.start.to_offset(&self.buffer);
4106        let chunks_start = content_start + range.start;
4107        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
4108
4109        let footer_height = if self.has_trailing_newline
4110            && range.start <= self.text_summary.len
4111            && range.end > self.text_summary.len
4112        {
4113            1
4114        } else {
4115            0
4116        };
4117
4118        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
4119
4120        ExcerptChunks {
4121            content_chunks,
4122            footer_height,
4123        }
4124    }
4125
4126    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
4127        let content_start = self.range.context.start.to_offset(&self.buffer);
4128        let bytes_start = content_start + range.start;
4129        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
4130        let footer_height = if self.has_trailing_newline
4131            && range.start <= self.text_summary.len
4132            && range.end > self.text_summary.len
4133        {
4134            1
4135        } else {
4136            0
4137        };
4138        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
4139
4140        ExcerptBytes {
4141            content_bytes,
4142            padding_height: footer_height,
4143            reversed: false,
4144        }
4145    }
4146
4147    fn reversed_bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
4148        let content_start = self.range.context.start.to_offset(&self.buffer);
4149        let bytes_start = content_start + range.start;
4150        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
4151        let footer_height = if self.has_trailing_newline
4152            && range.start <= self.text_summary.len
4153            && range.end > self.text_summary.len
4154        {
4155            1
4156        } else {
4157            0
4158        };
4159        let content_bytes = self.buffer.reversed_bytes_in_range(bytes_start..bytes_end);
4160
4161        ExcerptBytes {
4162            content_bytes,
4163            padding_height: footer_height,
4164            reversed: true,
4165        }
4166    }
4167
4168    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
4169        if text_anchor
4170            .cmp(&self.range.context.start, &self.buffer)
4171            .is_lt()
4172        {
4173            self.range.context.start
4174        } else if text_anchor
4175            .cmp(&self.range.context.end, &self.buffer)
4176            .is_gt()
4177        {
4178            self.range.context.end
4179        } else {
4180            text_anchor
4181        }
4182    }
4183
4184    fn contains(&self, anchor: &Anchor) -> bool {
4185        Some(self.buffer_id) == anchor.buffer_id
4186            && self
4187                .range
4188                .context
4189                .start
4190                .cmp(&anchor.text_anchor, &self.buffer)
4191                .is_le()
4192            && self
4193                .range
4194                .context
4195                .end
4196                .cmp(&anchor.text_anchor, &self.buffer)
4197                .is_ge()
4198    }
4199
4200    /// The [`Excerpt`]'s start offset in its [`Buffer`]
4201    fn buffer_start_offset(&self) -> usize {
4202        self.range.context.start.to_offset(&self.buffer)
4203    }
4204
4205    /// The [`Excerpt`]'s end offset in its [`Buffer`]
4206    fn buffer_end_offset(&self) -> usize {
4207        self.buffer_start_offset() + self.text_summary.len
4208    }
4209}
4210
4211impl<'a> MultiBufferExcerpt<'a> {
4212    fn new(excerpt: &'a Excerpt, excerpt_offset: usize) -> Self {
4213        MultiBufferExcerpt {
4214            excerpt,
4215            excerpt_offset,
4216        }
4217    }
4218
4219    pub fn buffer(&self) -> &'a BufferSnapshot {
4220        &self.excerpt.buffer
4221    }
4222
4223    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
4224    pub fn map_offset_to_buffer(&self, offset: usize) -> usize {
4225        self.excerpt.buffer_start_offset() + offset.saturating_sub(self.excerpt_offset)
4226    }
4227
4228    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
4229    pub fn map_range_to_buffer(&self, range: Range<usize>) -> Range<usize> {
4230        self.map_offset_to_buffer(range.start)..self.map_offset_to_buffer(range.end)
4231    }
4232
4233    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
4234    pub fn map_offset_from_buffer(&self, buffer_offset: usize) -> usize {
4235        let mut buffer_offset_in_excerpt =
4236            buffer_offset.saturating_sub(self.excerpt.buffer_start_offset());
4237        buffer_offset_in_excerpt =
4238            cmp::min(buffer_offset_in_excerpt, self.excerpt.text_summary.len);
4239
4240        self.excerpt_offset + buffer_offset_in_excerpt
4241    }
4242
4243    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
4244    pub fn map_range_from_buffer(&self, buffer_range: Range<usize>) -> Range<usize> {
4245        self.map_offset_from_buffer(buffer_range.start)
4246            ..self.map_offset_from_buffer(buffer_range.end)
4247    }
4248
4249    /// Returns true if the entirety of the given range is in the buffer's excerpt
4250    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
4251        range.start >= self.excerpt.buffer_start_offset()
4252            && range.end <= self.excerpt.buffer_end_offset()
4253    }
4254}
4255
4256impl ExcerptId {
4257    pub fn min() -> Self {
4258        Self(0)
4259    }
4260
4261    pub fn max() -> Self {
4262        Self(usize::MAX)
4263    }
4264
4265    pub fn to_proto(&self) -> u64 {
4266        self.0 as _
4267    }
4268
4269    pub fn from_proto(proto: u64) -> Self {
4270        Self(proto as _)
4271    }
4272
4273    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
4274        let a = snapshot.excerpt_locator_for_id(*self);
4275        let b = snapshot.excerpt_locator_for_id(*other);
4276        a.cmp(b).then_with(|| self.0.cmp(&other.0))
4277    }
4278}
4279
4280impl Into<usize> for ExcerptId {
4281    fn into(self) -> usize {
4282        self.0
4283    }
4284}
4285
4286impl fmt::Debug for Excerpt {
4287    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
4288        f.debug_struct("Excerpt")
4289            .field("id", &self.id)
4290            .field("locator", &self.locator)
4291            .field("buffer_id", &self.buffer_id)
4292            .field("range", &self.range)
4293            .field("text_summary", &self.text_summary)
4294            .field("has_trailing_newline", &self.has_trailing_newline)
4295            .finish()
4296    }
4297}
4298
4299impl sum_tree::Item for Excerpt {
4300    type Summary = ExcerptSummary;
4301
4302    fn summary(&self) -> Self::Summary {
4303        let mut text = self.text_summary.clone();
4304        if self.has_trailing_newline {
4305            text += TextSummary::from("\n");
4306        }
4307        ExcerptSummary {
4308            excerpt_id: self.id,
4309            excerpt_locator: self.locator.clone(),
4310            max_buffer_row: MultiBufferRow(self.max_buffer_row),
4311            text,
4312        }
4313    }
4314}
4315
4316impl sum_tree::Item for ExcerptIdMapping {
4317    type Summary = ExcerptId;
4318
4319    fn summary(&self) -> Self::Summary {
4320        self.id
4321    }
4322}
4323
4324impl sum_tree::KeyedItem for ExcerptIdMapping {
4325    type Key = ExcerptId;
4326
4327    fn key(&self) -> Self::Key {
4328        self.id
4329    }
4330}
4331
4332impl sum_tree::Summary for ExcerptId {
4333    type Context = ();
4334
4335    fn add_summary(&mut self, other: &Self, _: &()) {
4336        *self = *other;
4337    }
4338}
4339
4340impl sum_tree::Summary for ExcerptSummary {
4341    type Context = ();
4342
4343    fn add_summary(&mut self, summary: &Self, _: &()) {
4344        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
4345        self.excerpt_locator = summary.excerpt_locator.clone();
4346        self.text.add_summary(&summary.text, &());
4347        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
4348    }
4349}
4350
4351impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
4352    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4353        *self += &summary.text;
4354    }
4355}
4356
4357impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
4358    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4359        *self += summary.text.len;
4360    }
4361}
4362
4363impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
4364    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
4365        Ord::cmp(self, &cursor_location.text.len)
4366    }
4367}
4368
4369impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
4370    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
4371        Ord::cmp(&Some(self), cursor_location)
4372    }
4373}
4374
4375impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
4376    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
4377        Ord::cmp(self, &cursor_location.excerpt_locator)
4378    }
4379}
4380
4381impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for OffsetUtf16 {
4382    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4383        *self += summary.text.len_utf16;
4384    }
4385}
4386
4387impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
4388    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4389        *self += summary.text.lines;
4390    }
4391}
4392
4393impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
4394    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4395        *self += summary.text.lines_utf16()
4396    }
4397}
4398
4399impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
4400    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4401        *self = Some(&summary.excerpt_locator);
4402    }
4403}
4404
4405impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
4406    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
4407        *self = Some(summary.excerpt_id);
4408    }
4409}
4410
4411impl<'a> MultiBufferRows<'a> {
4412    pub fn seek(&mut self, row: MultiBufferRow) {
4413        self.buffer_row_range = 0..0;
4414
4415        self.excerpts
4416            .seek_forward(&Point::new(row.0, 0), Bias::Right, &());
4417        if self.excerpts.item().is_none() {
4418            self.excerpts.prev(&());
4419
4420            if self.excerpts.item().is_none() && row.0 == 0 {
4421                self.buffer_row_range = 0..1;
4422                return;
4423            }
4424        }
4425
4426        if let Some(excerpt) = self.excerpts.item() {
4427            let overshoot = row.0 - self.excerpts.start().row;
4428            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
4429            self.buffer_row_range.start = excerpt_start + overshoot;
4430            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
4431        }
4432    }
4433}
4434
4435impl<'a> Iterator for MultiBufferRows<'a> {
4436    type Item = Option<u32>;
4437
4438    fn next(&mut self) -> Option<Self::Item> {
4439        loop {
4440            if !self.buffer_row_range.is_empty() {
4441                let row = Some(self.buffer_row_range.start);
4442                self.buffer_row_range.start += 1;
4443                return Some(row);
4444            }
4445            self.excerpts.item()?;
4446            self.excerpts.next(&());
4447            let excerpt = self.excerpts.item()?;
4448            self.buffer_row_range.start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
4449            self.buffer_row_range.end =
4450                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
4451        }
4452    }
4453}
4454
4455impl<'a> MultiBufferChunks<'a> {
4456    pub fn offset(&self) -> usize {
4457        self.range.start
4458    }
4459
4460    pub fn seek(&mut self, offset: usize) {
4461        self.range.start = offset;
4462        self.excerpts.seek(&offset, Bias::Right, &());
4463        if let Some(excerpt) = self.excerpts.item() {
4464            self.excerpt_chunks = Some(excerpt.chunks_in_range(
4465                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
4466                self.language_aware,
4467            ));
4468        } else {
4469            self.excerpt_chunks = None;
4470        }
4471    }
4472}
4473
4474impl<'a> Iterator for MultiBufferChunks<'a> {
4475    type Item = Chunk<'a>;
4476
4477    fn next(&mut self) -> Option<Self::Item> {
4478        if self.range.is_empty() {
4479            None
4480        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
4481            self.range.start += chunk.text.len();
4482            Some(chunk)
4483        } else {
4484            self.excerpts.next(&());
4485            let excerpt = self.excerpts.item()?;
4486            self.excerpt_chunks = Some(excerpt.chunks_in_range(
4487                0..self.range.end - self.excerpts.start(),
4488                self.language_aware,
4489            ));
4490            self.next()
4491        }
4492    }
4493}
4494
4495impl<'a> MultiBufferBytes<'a> {
4496    fn consume(&mut self, len: usize) {
4497        self.range.start += len;
4498        self.chunk = &self.chunk[len..];
4499
4500        if !self.range.is_empty() && self.chunk.is_empty() {
4501            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
4502                self.chunk = chunk;
4503            } else {
4504                self.excerpts.next(&());
4505                if let Some(excerpt) = self.excerpts.item() {
4506                    let mut excerpt_bytes =
4507                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
4508                    self.chunk = excerpt_bytes.next().unwrap();
4509                    self.excerpt_bytes = Some(excerpt_bytes);
4510                }
4511            }
4512        }
4513    }
4514}
4515
4516impl<'a> Iterator for MultiBufferBytes<'a> {
4517    type Item = &'a [u8];
4518
4519    fn next(&mut self) -> Option<Self::Item> {
4520        let chunk = self.chunk;
4521        if chunk.is_empty() {
4522            None
4523        } else {
4524            self.consume(chunk.len());
4525            Some(chunk)
4526        }
4527    }
4528}
4529
4530impl<'a> io::Read for MultiBufferBytes<'a> {
4531    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4532        let len = cmp::min(buf.len(), self.chunk.len());
4533        buf[..len].copy_from_slice(&self.chunk[..len]);
4534        if len > 0 {
4535            self.consume(len);
4536        }
4537        Ok(len)
4538    }
4539}
4540
4541impl<'a> ReversedMultiBufferBytes<'a> {
4542    fn consume(&mut self, len: usize) {
4543        self.range.end -= len;
4544        self.chunk = &self.chunk[..self.chunk.len() - len];
4545
4546        if !self.range.is_empty() && self.chunk.is_empty() {
4547            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
4548                self.chunk = chunk;
4549            } else {
4550                self.excerpts.prev(&());
4551                if let Some(excerpt) = self.excerpts.item() {
4552                    let mut excerpt_bytes = excerpt.reversed_bytes_in_range(
4553                        self.range.start.saturating_sub(*self.excerpts.start())..usize::MAX,
4554                    );
4555                    self.chunk = excerpt_bytes.next().unwrap();
4556                    self.excerpt_bytes = Some(excerpt_bytes);
4557                }
4558            }
4559        } else {
4560        }
4561    }
4562}
4563
4564impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
4565    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
4566        let len = cmp::min(buf.len(), self.chunk.len());
4567        buf[..len].copy_from_slice(&self.chunk[..len]);
4568        buf[..len].reverse();
4569        if len > 0 {
4570            self.consume(len);
4571        }
4572        Ok(len)
4573    }
4574}
4575impl<'a> Iterator for ExcerptBytes<'a> {
4576    type Item = &'a [u8];
4577
4578    fn next(&mut self) -> Option<Self::Item> {
4579        if self.reversed && self.padding_height > 0 {
4580            let result = &NEWLINES[..self.padding_height];
4581            self.padding_height = 0;
4582            return Some(result);
4583        }
4584
4585        if let Some(chunk) = self.content_bytes.next() {
4586            if !chunk.is_empty() {
4587                return Some(chunk);
4588            }
4589        }
4590
4591        if self.padding_height > 0 {
4592            let result = &NEWLINES[..self.padding_height];
4593            self.padding_height = 0;
4594            return Some(result);
4595        }
4596
4597        None
4598    }
4599}
4600
4601impl<'a> Iterator for ExcerptChunks<'a> {
4602    type Item = Chunk<'a>;
4603
4604    fn next(&mut self) -> Option<Self::Item> {
4605        if let Some(chunk) = self.content_chunks.next() {
4606            return Some(chunk);
4607        }
4608
4609        if self.footer_height > 0 {
4610            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
4611            self.footer_height = 0;
4612            return Some(Chunk {
4613                text,
4614                ..Default::default()
4615            });
4616        }
4617
4618        None
4619    }
4620}
4621
4622impl ToOffset for Point {
4623    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4624        snapshot.point_to_offset(*self)
4625    }
4626}
4627
4628impl ToOffset for usize {
4629    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4630        assert!(*self <= snapshot.len(), "offset is out of range");
4631        *self
4632    }
4633}
4634
4635impl ToOffset for OffsetUtf16 {
4636    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4637        snapshot.offset_utf16_to_offset(*self)
4638    }
4639}
4640
4641impl ToOffset for PointUtf16 {
4642    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4643        snapshot.point_utf16_to_offset(*self)
4644    }
4645}
4646
4647impl ToOffsetUtf16 for OffsetUtf16 {
4648    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4649        *self
4650    }
4651}
4652
4653impl ToOffsetUtf16 for usize {
4654    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4655        snapshot.offset_to_offset_utf16(*self)
4656    }
4657}
4658
4659impl ToPoint for usize {
4660    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
4661        snapshot.offset_to_point(*self)
4662    }
4663}
4664
4665impl ToPoint for Point {
4666    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
4667        *self
4668    }
4669}
4670
4671impl ToPointUtf16 for usize {
4672    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4673        snapshot.offset_to_point_utf16(*self)
4674    }
4675}
4676
4677impl ToPointUtf16 for Point {
4678    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4679        snapshot.point_to_point_utf16(*self)
4680    }
4681}
4682
4683impl ToPointUtf16 for PointUtf16 {
4684    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
4685        *self
4686    }
4687}
4688
4689pub fn build_excerpt_ranges<T>(
4690    buffer: &BufferSnapshot,
4691    ranges: &[Range<T>],
4692    context_line_count: u32,
4693) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
4694where
4695    T: text::ToPoint,
4696{
4697    let max_point = buffer.max_point();
4698    let mut range_counts = Vec::new();
4699    let mut excerpt_ranges = Vec::new();
4700    let mut range_iter = ranges
4701        .iter()
4702        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
4703        .peekable();
4704    while let Some(range) = range_iter.next() {
4705        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
4706        let row = (range.end.row + context_line_count).min(max_point.row);
4707        let mut excerpt_end = Point::new(row, buffer.line_len(row));
4708
4709        let mut ranges_in_excerpt = 1;
4710
4711        while let Some(next_range) = range_iter.peek() {
4712            if next_range.start.row <= excerpt_end.row + context_line_count {
4713                let row = (next_range.end.row + context_line_count).min(max_point.row);
4714                excerpt_end = Point::new(row, buffer.line_len(row));
4715
4716                ranges_in_excerpt += 1;
4717                range_iter.next();
4718            } else {
4719                break;
4720            }
4721        }
4722
4723        excerpt_ranges.push(ExcerptRange {
4724            context: excerpt_start..excerpt_end,
4725            primary: Some(range),
4726        });
4727        range_counts.push(ranges_in_excerpt);
4728    }
4729
4730    (excerpt_ranges, range_counts)
4731}
4732
4733#[cfg(test)]
4734mod tests {
4735    use super::*;
4736    use futures::StreamExt;
4737    use gpui::{AppContext, Context, TestAppContext};
4738    use language::{Buffer, Rope};
4739    use parking_lot::RwLock;
4740    use rand::prelude::*;
4741    use settings::SettingsStore;
4742    use std::env;
4743    use util::test::sample_text;
4744
4745    #[ctor::ctor]
4746    fn init_logger() {
4747        if std::env::var("RUST_LOG").is_ok() {
4748            env_logger::init();
4749        }
4750    }
4751
4752    #[gpui::test]
4753    fn test_singleton(cx: &mut AppContext) {
4754        let buffer = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
4755        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4756
4757        let snapshot = multibuffer.read(cx).snapshot(cx);
4758        assert_eq!(snapshot.text(), buffer.read(cx).text());
4759
4760        assert_eq!(
4761            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4762            (0..buffer.read(cx).row_count())
4763                .map(Some)
4764                .collect::<Vec<_>>()
4765        );
4766
4767        buffer.update(cx, |buffer, cx| buffer.edit([(1..3, "XXX\n")], None, cx));
4768        let snapshot = multibuffer.read(cx).snapshot(cx);
4769
4770        assert_eq!(snapshot.text(), buffer.read(cx).text());
4771        assert_eq!(
4772            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4773            (0..buffer.read(cx).row_count())
4774                .map(Some)
4775                .collect::<Vec<_>>()
4776        );
4777    }
4778
4779    #[gpui::test]
4780    fn test_remote(cx: &mut AppContext) {
4781        let host_buffer = cx.new_model(|cx| Buffer::local("a", cx));
4782        let guest_buffer = cx.new_model(|cx| {
4783            let state = host_buffer.read(cx).to_proto();
4784            let ops = cx
4785                .background_executor()
4786                .block(host_buffer.read(cx).serialize_ops(None, cx));
4787            let mut buffer = Buffer::from_proto(1, Capability::ReadWrite, state, None).unwrap();
4788            buffer
4789                .apply_ops(
4790                    ops.into_iter()
4791                        .map(|op| language::proto::deserialize_operation(op).unwrap()),
4792                    cx,
4793                )
4794                .unwrap();
4795            buffer
4796        });
4797        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
4798        let snapshot = multibuffer.read(cx).snapshot(cx);
4799        assert_eq!(snapshot.text(), "a");
4800
4801        guest_buffer.update(cx, |buffer, cx| buffer.edit([(1..1, "b")], None, cx));
4802        let snapshot = multibuffer.read(cx).snapshot(cx);
4803        assert_eq!(snapshot.text(), "ab");
4804
4805        guest_buffer.update(cx, |buffer, cx| buffer.edit([(2..2, "c")], None, cx));
4806        let snapshot = multibuffer.read(cx).snapshot(cx);
4807        assert_eq!(snapshot.text(), "abc");
4808    }
4809
4810    #[gpui::test]
4811    fn test_excerpt_boundaries_and_clipping(cx: &mut AppContext) {
4812        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
4813        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
4814        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4815
4816        let events = Arc::new(RwLock::new(Vec::<Event>::new()));
4817        multibuffer.update(cx, |_, cx| {
4818            let events = events.clone();
4819            cx.subscribe(&multibuffer, move |_, _, event, _| {
4820                if let Event::Edited { .. } = event {
4821                    events.write().push(event.clone())
4822                }
4823            })
4824            .detach();
4825        });
4826
4827        let subscription = multibuffer.update(cx, |multibuffer, cx| {
4828            let subscription = multibuffer.subscribe();
4829            multibuffer.push_excerpts(
4830                buffer_1.clone(),
4831                [ExcerptRange {
4832                    context: Point::new(1, 2)..Point::new(2, 5),
4833                    primary: None,
4834                }],
4835                cx,
4836            );
4837            assert_eq!(
4838                subscription.consume().into_inner(),
4839                [Edit {
4840                    old: 0..0,
4841                    new: 0..10
4842                }]
4843            );
4844
4845            multibuffer.push_excerpts(
4846                buffer_1.clone(),
4847                [ExcerptRange {
4848                    context: Point::new(3, 3)..Point::new(4, 4),
4849                    primary: None,
4850                }],
4851                cx,
4852            );
4853            multibuffer.push_excerpts(
4854                buffer_2.clone(),
4855                [ExcerptRange {
4856                    context: Point::new(3, 1)..Point::new(3, 3),
4857                    primary: None,
4858                }],
4859                cx,
4860            );
4861            assert_eq!(
4862                subscription.consume().into_inner(),
4863                [Edit {
4864                    old: 10..10,
4865                    new: 10..22
4866                }]
4867            );
4868
4869            subscription
4870        });
4871
4872        // Adding excerpts emits an edited event.
4873        assert_eq!(
4874            events.read().as_slice(),
4875            &[
4876                Event::Edited {
4877                    singleton_buffer_edited: false
4878                },
4879                Event::Edited {
4880                    singleton_buffer_edited: false
4881                },
4882                Event::Edited {
4883                    singleton_buffer_edited: false
4884                }
4885            ]
4886        );
4887
4888        let snapshot = multibuffer.read(cx).snapshot(cx);
4889        assert_eq!(
4890            snapshot.text(),
4891            concat!(
4892                "bbbb\n",  // Preserve newlines
4893                "ccccc\n", //
4894                "ddd\n",   //
4895                "eeee\n",  //
4896                "jj"       //
4897            )
4898        );
4899        assert_eq!(
4900            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
4901            [Some(1), Some(2), Some(3), Some(4), Some(3)]
4902        );
4903        assert_eq!(
4904            snapshot.buffer_rows(MultiBufferRow(2)).collect::<Vec<_>>(),
4905            [Some(3), Some(4), Some(3)]
4906        );
4907        assert_eq!(
4908            snapshot.buffer_rows(MultiBufferRow(4)).collect::<Vec<_>>(),
4909            [Some(3)]
4910        );
4911        assert_eq!(
4912            snapshot.buffer_rows(MultiBufferRow(5)).collect::<Vec<_>>(),
4913            []
4914        );
4915
4916        assert_eq!(
4917            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
4918            &[
4919                (MultiBufferRow(0), "bbbb\nccccc".to_string(), true),
4920                (MultiBufferRow(2), "ddd\neeee".to_string(), false),
4921                (MultiBufferRow(4), "jj".to_string(), true),
4922            ]
4923        );
4924        assert_eq!(
4925            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
4926            &[(MultiBufferRow(0), "bbbb\nccccc".to_string(), true)]
4927        );
4928        assert_eq!(
4929            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
4930            &[]
4931        );
4932        assert_eq!(
4933            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
4934            &[]
4935        );
4936        assert_eq!(
4937            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4938            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4939        );
4940        assert_eq!(
4941            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4942            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4943        );
4944        assert_eq!(
4945            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
4946            &[(MultiBufferRow(2), "ddd\neeee".to_string(), false)]
4947        );
4948        assert_eq!(
4949            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
4950            &[(MultiBufferRow(4), "jj".to_string(), true)]
4951        );
4952        assert_eq!(
4953            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
4954            &[]
4955        );
4956
4957        buffer_1.update(cx, |buffer, cx| {
4958            let text = "\n";
4959            buffer.edit(
4960                [
4961                    (Point::new(0, 0)..Point::new(0, 0), text),
4962                    (Point::new(2, 1)..Point::new(2, 3), text),
4963                ],
4964                None,
4965                cx,
4966            );
4967        });
4968
4969        let snapshot = multibuffer.read(cx).snapshot(cx);
4970        assert_eq!(
4971            snapshot.text(),
4972            concat!(
4973                "bbbb\n", // Preserve newlines
4974                "c\n",    //
4975                "cc\n",   //
4976                "ddd\n",  //
4977                "eeee\n", //
4978                "jj"      //
4979            )
4980        );
4981
4982        assert_eq!(
4983            subscription.consume().into_inner(),
4984            [Edit {
4985                old: 6..8,
4986                new: 6..7
4987            }]
4988        );
4989
4990        let snapshot = multibuffer.read(cx).snapshot(cx);
4991        assert_eq!(
4992            snapshot.clip_point(Point::new(0, 5), Bias::Left),
4993            Point::new(0, 4)
4994        );
4995        assert_eq!(
4996            snapshot.clip_point(Point::new(0, 5), Bias::Right),
4997            Point::new(0, 4)
4998        );
4999        assert_eq!(
5000            snapshot.clip_point(Point::new(5, 1), Bias::Right),
5001            Point::new(5, 1)
5002        );
5003        assert_eq!(
5004            snapshot.clip_point(Point::new(5, 2), Bias::Right),
5005            Point::new(5, 2)
5006        );
5007        assert_eq!(
5008            snapshot.clip_point(Point::new(5, 3), Bias::Right),
5009            Point::new(5, 2)
5010        );
5011
5012        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
5013            let (buffer_2_excerpt_id, _) =
5014                multibuffer.excerpts_for_buffer(&buffer_2, cx)[0].clone();
5015            multibuffer.remove_excerpts([buffer_2_excerpt_id], cx);
5016            multibuffer.snapshot(cx)
5017        });
5018
5019        assert_eq!(
5020            snapshot.text(),
5021            concat!(
5022                "bbbb\n", // Preserve newlines
5023                "c\n",    //
5024                "cc\n",   //
5025                "ddd\n",  //
5026                "eeee",   //
5027            )
5028        );
5029
5030        fn boundaries_in_range(
5031            range: Range<Point>,
5032            snapshot: &MultiBufferSnapshot,
5033        ) -> Vec<(MultiBufferRow, String, bool)> {
5034            snapshot
5035                .excerpt_boundaries_in_range(range)
5036                .filter_map(|boundary| {
5037                    let starts_new_buffer = boundary.starts_new_buffer();
5038                    boundary.next.map(|next| {
5039                        (
5040                            boundary.row,
5041                            next.buffer
5042                                .text_for_range(next.range.context)
5043                                .collect::<String>(),
5044                            starts_new_buffer,
5045                        )
5046                    })
5047                })
5048                .collect::<Vec<_>>()
5049        }
5050    }
5051
5052    #[gpui::test]
5053    fn test_excerpt_events(cx: &mut AppContext) {
5054        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(10, 3, 'a'), cx));
5055        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(10, 3, 'm'), cx));
5056
5057        let leader_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5058        let follower_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5059        let follower_edit_event_count = Arc::new(RwLock::new(0));
5060
5061        follower_multibuffer.update(cx, |_, cx| {
5062            let follower_edit_event_count = follower_edit_event_count.clone();
5063            cx.subscribe(
5064                &leader_multibuffer,
5065                move |follower, _, event, cx| match event.clone() {
5066                    Event::ExcerptsAdded {
5067                        buffer,
5068                        predecessor,
5069                        excerpts,
5070                    } => follower.insert_excerpts_with_ids_after(predecessor, buffer, excerpts, cx),
5071                    Event::ExcerptsRemoved { ids } => follower.remove_excerpts(ids, cx),
5072                    Event::Edited { .. } => {
5073                        *follower_edit_event_count.write() += 1;
5074                    }
5075                    _ => {}
5076                },
5077            )
5078            .detach();
5079        });
5080
5081        leader_multibuffer.update(cx, |leader, cx| {
5082            leader.push_excerpts(
5083                buffer_1.clone(),
5084                [
5085                    ExcerptRange {
5086                        context: 0..8,
5087                        primary: None,
5088                    },
5089                    ExcerptRange {
5090                        context: 12..16,
5091                        primary: None,
5092                    },
5093                ],
5094                cx,
5095            );
5096            leader.insert_excerpts_after(
5097                leader.excerpt_ids()[0],
5098                buffer_2.clone(),
5099                [
5100                    ExcerptRange {
5101                        context: 0..5,
5102                        primary: None,
5103                    },
5104                    ExcerptRange {
5105                        context: 10..15,
5106                        primary: None,
5107                    },
5108                ],
5109                cx,
5110            )
5111        });
5112        assert_eq!(
5113            leader_multibuffer.read(cx).snapshot(cx).text(),
5114            follower_multibuffer.read(cx).snapshot(cx).text(),
5115        );
5116        assert_eq!(*follower_edit_event_count.read(), 2);
5117
5118        leader_multibuffer.update(cx, |leader, cx| {
5119            let excerpt_ids = leader.excerpt_ids();
5120            leader.remove_excerpts([excerpt_ids[1], excerpt_ids[3]], cx);
5121        });
5122        assert_eq!(
5123            leader_multibuffer.read(cx).snapshot(cx).text(),
5124            follower_multibuffer.read(cx).snapshot(cx).text(),
5125        );
5126        assert_eq!(*follower_edit_event_count.read(), 3);
5127
5128        // Removing an empty set of excerpts is a noop.
5129        leader_multibuffer.update(cx, |leader, cx| {
5130            leader.remove_excerpts([], cx);
5131        });
5132        assert_eq!(
5133            leader_multibuffer.read(cx).snapshot(cx).text(),
5134            follower_multibuffer.read(cx).snapshot(cx).text(),
5135        );
5136        assert_eq!(*follower_edit_event_count.read(), 3);
5137
5138        // Adding an empty set of excerpts is a noop.
5139        leader_multibuffer.update(cx, |leader, cx| {
5140            leader.push_excerpts::<usize>(buffer_2.clone(), [], cx);
5141        });
5142        assert_eq!(
5143            leader_multibuffer.read(cx).snapshot(cx).text(),
5144            follower_multibuffer.read(cx).snapshot(cx).text(),
5145        );
5146        assert_eq!(*follower_edit_event_count.read(), 3);
5147
5148        leader_multibuffer.update(cx, |leader, cx| {
5149            leader.clear(cx);
5150        });
5151        assert_eq!(
5152            leader_multibuffer.read(cx).snapshot(cx).text(),
5153            follower_multibuffer.read(cx).snapshot(cx).text(),
5154        );
5155        assert_eq!(*follower_edit_event_count.read(), 4);
5156    }
5157
5158    #[gpui::test]
5159    fn test_expand_excerpts(cx: &mut AppContext) {
5160        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5161        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5162
5163        multibuffer.update(cx, |multibuffer, cx| {
5164            multibuffer.push_excerpts_with_context_lines(
5165                buffer.clone(),
5166                vec![
5167                    // Note that in this test, this first excerpt
5168                    // does not contain a new line
5169                    Point::new(3, 2)..Point::new(3, 3),
5170                    Point::new(7, 1)..Point::new(7, 3),
5171                    Point::new(15, 0)..Point::new(15, 0),
5172                ],
5173                1,
5174                cx,
5175            )
5176        });
5177
5178        let snapshot = multibuffer.read(cx).snapshot(cx);
5179
5180        assert_eq!(
5181            snapshot.text(),
5182            concat!(
5183                "ccc\n", //
5184                "ddd\n", //
5185                "eee",   //
5186                "\n",    // End of excerpt
5187                "ggg\n", //
5188                "hhh\n", //
5189                "iii",   //
5190                "\n",    // End of excerpt
5191                "ooo\n", //
5192                "ppp\n", //
5193                "qqq",   // End of excerpt
5194            )
5195        );
5196        drop(snapshot);
5197
5198        multibuffer.update(cx, |multibuffer, cx| {
5199            multibuffer.expand_excerpts(
5200                multibuffer.excerpt_ids(),
5201                1,
5202                ExpandExcerptDirection::UpAndDown,
5203                cx,
5204            )
5205        });
5206
5207        let snapshot = multibuffer.read(cx).snapshot(cx);
5208
5209        // Expanding context lines causes the line containing 'fff' to appear in two different excerpts.
5210        // We don't attempt to merge them, because removing the excerpt could create inconsistency with other layers
5211        // that are tracking excerpt ids.
5212        assert_eq!(
5213            snapshot.text(),
5214            concat!(
5215                "bbb\n", //
5216                "ccc\n", //
5217                "ddd\n", //
5218                "eee\n", //
5219                "fff\n", // End of excerpt
5220                "fff\n", //
5221                "ggg\n", //
5222                "hhh\n", //
5223                "iii\n", //
5224                "jjj\n", // End of excerpt
5225                "nnn\n", //
5226                "ooo\n", //
5227                "ppp\n", //
5228                "qqq\n", //
5229                "rrr",   // End of excerpt
5230            )
5231        );
5232    }
5233
5234    #[gpui::test]
5235    fn test_push_excerpts_with_context_lines(cx: &mut AppContext) {
5236        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5237        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5238        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
5239            multibuffer.push_excerpts_with_context_lines(
5240                buffer.clone(),
5241                vec![
5242                    // Note that in this test, this first excerpt
5243                    // does contain a new line
5244                    Point::new(3, 2)..Point::new(4, 2),
5245                    Point::new(7, 1)..Point::new(7, 3),
5246                    Point::new(15, 0)..Point::new(15, 0),
5247                ],
5248                2,
5249                cx,
5250            )
5251        });
5252
5253        let snapshot = multibuffer.read(cx).snapshot(cx);
5254        assert_eq!(
5255            snapshot.text(),
5256            concat!(
5257                "bbb\n", // Preserve newlines
5258                "ccc\n", //
5259                "ddd\n", //
5260                "eee\n", //
5261                "fff\n", //
5262                "ggg\n", //
5263                "hhh\n", //
5264                "iii\n", //
5265                "jjj\n", //
5266                "nnn\n", //
5267                "ooo\n", //
5268                "ppp\n", //
5269                "qqq\n", //
5270                "rrr",   //
5271            )
5272        );
5273
5274        assert_eq!(
5275            anchor_ranges
5276                .iter()
5277                .map(|range| range.to_point(&snapshot))
5278                .collect::<Vec<_>>(),
5279            vec![
5280                Point::new(2, 2)..Point::new(3, 2),
5281                Point::new(6, 1)..Point::new(6, 3),
5282                Point::new(11, 0)..Point::new(11, 0)
5283            ]
5284        );
5285    }
5286
5287    #[gpui::test]
5288    async fn test_stream_excerpts_with_context_lines(cx: &mut TestAppContext) {
5289        let buffer = cx.new_model(|cx| Buffer::local(sample_text(20, 3, 'a'), cx));
5290        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5291        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
5292            let snapshot = buffer.read(cx);
5293            let ranges = vec![
5294                snapshot.anchor_before(Point::new(3, 2))..snapshot.anchor_before(Point::new(4, 2)),
5295                snapshot.anchor_before(Point::new(7, 1))..snapshot.anchor_before(Point::new(7, 3)),
5296                snapshot.anchor_before(Point::new(15, 0))
5297                    ..snapshot.anchor_before(Point::new(15, 0)),
5298            ];
5299            multibuffer.stream_excerpts_with_context_lines(buffer.clone(), ranges, 2, cx)
5300        });
5301
5302        let anchor_ranges = anchor_ranges.collect::<Vec<_>>().await;
5303
5304        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
5305        assert_eq!(
5306            snapshot.text(),
5307            concat!(
5308                "bbb\n", //
5309                "ccc\n", //
5310                "ddd\n", //
5311                "eee\n", //
5312                "fff\n", //
5313                "ggg\n", //
5314                "hhh\n", //
5315                "iii\n", //
5316                "jjj\n", //
5317                "nnn\n", //
5318                "ooo\n", //
5319                "ppp\n", //
5320                "qqq\n", //
5321                "rrr",   //
5322            )
5323        );
5324
5325        assert_eq!(
5326            anchor_ranges
5327                .iter()
5328                .map(|range| range.to_point(&snapshot))
5329                .collect::<Vec<_>>(),
5330            vec![
5331                Point::new(2, 2)..Point::new(3, 2),
5332                Point::new(6, 1)..Point::new(6, 3),
5333                Point::new(11, 0)..Point::new(11, 0)
5334            ]
5335        );
5336    }
5337
5338    #[gpui::test]
5339    fn test_empty_multibuffer(cx: &mut AppContext) {
5340        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5341
5342        let snapshot = multibuffer.read(cx).snapshot(cx);
5343        assert_eq!(snapshot.text(), "");
5344        assert_eq!(
5345            snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
5346            &[Some(0)]
5347        );
5348        assert_eq!(
5349            snapshot.buffer_rows(MultiBufferRow(1)).collect::<Vec<_>>(),
5350            &[]
5351        );
5352    }
5353
5354    #[gpui::test]
5355    fn test_singleton_multibuffer_anchors(cx: &mut AppContext) {
5356        let buffer = cx.new_model(|cx| Buffer::local("abcd", cx));
5357        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
5358        let old_snapshot = multibuffer.read(cx).snapshot(cx);
5359        buffer.update(cx, |buffer, cx| {
5360            buffer.edit([(0..0, "X")], None, cx);
5361            buffer.edit([(5..5, "Y")], None, cx);
5362        });
5363        let new_snapshot = multibuffer.read(cx).snapshot(cx);
5364
5365        assert_eq!(old_snapshot.text(), "abcd");
5366        assert_eq!(new_snapshot.text(), "XabcdY");
5367
5368        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
5369        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
5370        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
5371        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
5372    }
5373
5374    #[gpui::test]
5375    fn test_multibuffer_anchors(cx: &mut AppContext) {
5376        let buffer_1 = cx.new_model(|cx| Buffer::local("abcd", cx));
5377        let buffer_2 = cx.new_model(|cx| Buffer::local("efghi", cx));
5378        let multibuffer = cx.new_model(|cx| {
5379            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
5380            multibuffer.push_excerpts(
5381                buffer_1.clone(),
5382                [ExcerptRange {
5383                    context: 0..4,
5384                    primary: None,
5385                }],
5386                cx,
5387            );
5388            multibuffer.push_excerpts(
5389                buffer_2.clone(),
5390                [ExcerptRange {
5391                    context: 0..5,
5392                    primary: None,
5393                }],
5394                cx,
5395            );
5396            multibuffer
5397        });
5398        let old_snapshot = multibuffer.read(cx).snapshot(cx);
5399
5400        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
5401        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
5402        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
5403        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
5404        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
5405        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
5406
5407        buffer_1.update(cx, |buffer, cx| {
5408            buffer.edit([(0..0, "W")], None, cx);
5409            buffer.edit([(5..5, "X")], None, cx);
5410        });
5411        buffer_2.update(cx, |buffer, cx| {
5412            buffer.edit([(0..0, "Y")], None, cx);
5413            buffer.edit([(6..6, "Z")], None, cx);
5414        });
5415        let new_snapshot = multibuffer.read(cx).snapshot(cx);
5416
5417        assert_eq!(old_snapshot.text(), "abcd\nefghi");
5418        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
5419
5420        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
5421        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
5422        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
5423        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
5424        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
5425        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
5426        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
5427        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
5428        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
5429        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
5430    }
5431
5432    #[gpui::test]
5433    fn test_resolving_anchors_after_replacing_their_excerpts(cx: &mut AppContext) {
5434        let buffer_1 = cx.new_model(|cx| Buffer::local("abcd", cx));
5435        let buffer_2 = cx.new_model(|cx| Buffer::local("ABCDEFGHIJKLMNOP", cx));
5436        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5437
5438        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
5439        // Add an excerpt from buffer 1 that spans this new insertion.
5440        buffer_1.update(cx, |buffer, cx| buffer.edit([(4..4, "123")], None, cx));
5441        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
5442            multibuffer
5443                .push_excerpts(
5444                    buffer_1.clone(),
5445                    [ExcerptRange {
5446                        context: 0..7,
5447                        primary: None,
5448                    }],
5449                    cx,
5450                )
5451                .pop()
5452                .unwrap()
5453        });
5454
5455        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
5456        assert_eq!(snapshot_1.text(), "abcd123");
5457
5458        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
5459        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
5460            multibuffer.remove_excerpts([excerpt_id_1], cx);
5461            let mut ids = multibuffer
5462                .push_excerpts(
5463                    buffer_2.clone(),
5464                    [
5465                        ExcerptRange {
5466                            context: 0..4,
5467                            primary: None,
5468                        },
5469                        ExcerptRange {
5470                            context: 6..10,
5471                            primary: None,
5472                        },
5473                        ExcerptRange {
5474                            context: 12..16,
5475                            primary: None,
5476                        },
5477                    ],
5478                    cx,
5479                )
5480                .into_iter();
5481            (ids.next().unwrap(), ids.next().unwrap())
5482        });
5483        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
5484        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
5485
5486        // The old excerpt id doesn't get reused.
5487        assert_ne!(excerpt_id_2, excerpt_id_1);
5488
5489        // Resolve some anchors from the previous snapshot in the new snapshot.
5490        // The current excerpts are from a different buffer, so we don't attempt to
5491        // resolve the old text anchor in the new buffer.
5492        assert_eq!(
5493            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
5494            0
5495        );
5496        assert_eq!(
5497            snapshot_2.summaries_for_anchors::<usize, _>(&[
5498                snapshot_1.anchor_before(2),
5499                snapshot_1.anchor_after(3)
5500            ]),
5501            vec![0, 0]
5502        );
5503
5504        // Refresh anchors from the old snapshot. The return value indicates that both
5505        // anchors lost their original excerpt.
5506        let refresh =
5507            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
5508        assert_eq!(
5509            refresh,
5510            &[
5511                (0, snapshot_2.anchor_before(0), false),
5512                (1, snapshot_2.anchor_after(0), false),
5513            ]
5514        );
5515
5516        // Replace the middle excerpt with a smaller excerpt in buffer 2,
5517        // that intersects the old excerpt.
5518        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
5519            multibuffer.remove_excerpts([excerpt_id_3], cx);
5520            multibuffer
5521                .insert_excerpts_after(
5522                    excerpt_id_2,
5523                    buffer_2.clone(),
5524                    [ExcerptRange {
5525                        context: 5..8,
5526                        primary: None,
5527                    }],
5528                    cx,
5529                )
5530                .pop()
5531                .unwrap()
5532        });
5533
5534        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
5535        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
5536        assert_ne!(excerpt_id_5, excerpt_id_3);
5537
5538        // Resolve some anchors from the previous snapshot in the new snapshot.
5539        // The third anchor can't be resolved, since its excerpt has been removed,
5540        // so it resolves to the same position as its predecessor.
5541        let anchors = [
5542            snapshot_2.anchor_before(0),
5543            snapshot_2.anchor_after(2),
5544            snapshot_2.anchor_after(6),
5545            snapshot_2.anchor_after(14),
5546        ];
5547        assert_eq!(
5548            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
5549            &[0, 2, 9, 13]
5550        );
5551
5552        let new_anchors = snapshot_3.refresh_anchors(&anchors);
5553        assert_eq!(
5554            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
5555            &[(0, true), (1, true), (2, true), (3, true)]
5556        );
5557        assert_eq!(
5558            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
5559            &[0, 2, 7, 13]
5560        );
5561    }
5562
5563    #[gpui::test(iterations = 100)]
5564    fn test_random_multibuffer(cx: &mut AppContext, mut rng: StdRng) {
5565        let operations = env::var("OPERATIONS")
5566            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
5567            .unwrap_or(10);
5568
5569        let mut buffers: Vec<Model<Buffer>> = Vec::new();
5570        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5571        let mut excerpt_ids = Vec::<ExcerptId>::new();
5572        let mut expected_excerpts = Vec::<(Model<Buffer>, Range<text::Anchor>)>::new();
5573        let mut anchors = Vec::new();
5574        let mut old_versions = Vec::new();
5575
5576        for _ in 0..operations {
5577            match rng.gen_range(0..100) {
5578                0..=14 if !buffers.is_empty() => {
5579                    let buffer = buffers.choose(&mut rng).unwrap();
5580                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
5581                }
5582                15..=19 if !expected_excerpts.is_empty() => {
5583                    multibuffer.update(cx, |multibuffer, cx| {
5584                        let ids = multibuffer.excerpt_ids();
5585                        let mut excerpts = HashSet::default();
5586                        for _ in 0..rng.gen_range(0..ids.len()) {
5587                            excerpts.extend(ids.choose(&mut rng).copied());
5588                        }
5589
5590                        let line_count = rng.gen_range(0..5);
5591
5592                        let excerpt_ixs = excerpts
5593                            .iter()
5594                            .map(|id| excerpt_ids.iter().position(|i| i == id).unwrap())
5595                            .collect::<Vec<_>>();
5596                        log::info!("Expanding excerpts {excerpt_ixs:?} by {line_count} lines");
5597                        multibuffer.expand_excerpts(
5598                            excerpts.iter().cloned(),
5599                            line_count,
5600                            ExpandExcerptDirection::UpAndDown,
5601                            cx,
5602                        );
5603
5604                        if line_count > 0 {
5605                            for id in excerpts {
5606                                let excerpt_ix = excerpt_ids.iter().position(|&i| i == id).unwrap();
5607                                let (buffer, range) = &mut expected_excerpts[excerpt_ix];
5608                                let snapshot = buffer.read(cx).snapshot();
5609                                let mut point_range = range.to_point(&snapshot);
5610                                point_range.start =
5611                                    Point::new(point_range.start.row.saturating_sub(line_count), 0);
5612                                point_range.end = snapshot.clip_point(
5613                                    Point::new(point_range.end.row + line_count, 0),
5614                                    Bias::Left,
5615                                );
5616                                point_range.end.column = snapshot.line_len(point_range.end.row);
5617                                *range = snapshot.anchor_before(point_range.start)
5618                                    ..snapshot.anchor_after(point_range.end);
5619                            }
5620                        }
5621                    });
5622                }
5623                20..=29 if !expected_excerpts.is_empty() => {
5624                    let mut ids_to_remove = vec![];
5625                    for _ in 0..rng.gen_range(1..=3) {
5626                        if expected_excerpts.is_empty() {
5627                            break;
5628                        }
5629
5630                        let ix = rng.gen_range(0..expected_excerpts.len());
5631                        ids_to_remove.push(excerpt_ids.remove(ix));
5632                        let (buffer, range) = expected_excerpts.remove(ix);
5633                        let buffer = buffer.read(cx);
5634                        log::info!(
5635                            "Removing excerpt {}: {:?}",
5636                            ix,
5637                            buffer
5638                                .text_for_range(range.to_offset(buffer))
5639                                .collect::<String>(),
5640                        );
5641                    }
5642                    let snapshot = multibuffer.read(cx).read(cx);
5643                    ids_to_remove.sort_unstable_by(|a, b| a.cmp(&b, &snapshot));
5644                    drop(snapshot);
5645                    multibuffer.update(cx, |multibuffer, cx| {
5646                        multibuffer.remove_excerpts(ids_to_remove, cx)
5647                    });
5648                }
5649                30..=39 if !expected_excerpts.is_empty() => {
5650                    let multibuffer = multibuffer.read(cx).read(cx);
5651                    let offset =
5652                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
5653                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
5654                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
5655                    anchors.push(multibuffer.anchor_at(offset, bias));
5656                    anchors.sort_by(|a, b| a.cmp(b, &multibuffer));
5657                }
5658                40..=44 if !anchors.is_empty() => {
5659                    let multibuffer = multibuffer.read(cx).read(cx);
5660                    let prev_len = anchors.len();
5661                    anchors = multibuffer
5662                        .refresh_anchors(&anchors)
5663                        .into_iter()
5664                        .map(|a| a.1)
5665                        .collect();
5666
5667                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
5668                    // overshoot its boundaries.
5669                    assert_eq!(anchors.len(), prev_len);
5670                    for anchor in &anchors {
5671                        if anchor.excerpt_id == ExcerptId::min()
5672                            || anchor.excerpt_id == ExcerptId::max()
5673                        {
5674                            continue;
5675                        }
5676
5677                        let excerpt = multibuffer.excerpt(anchor.excerpt_id).unwrap();
5678                        assert_eq!(excerpt.id, anchor.excerpt_id);
5679                        assert!(excerpt.contains(anchor));
5680                    }
5681                }
5682                _ => {
5683                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
5684                        let base_text = util::RandomCharIter::new(&mut rng)
5685                            .take(25)
5686                            .collect::<String>();
5687
5688                        buffers.push(cx.new_model(|cx| Buffer::local(base_text, cx)));
5689                        buffers.last().unwrap()
5690                    } else {
5691                        buffers.choose(&mut rng).unwrap()
5692                    };
5693
5694                    let buffer = buffer_handle.read(cx);
5695                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
5696                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5697                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
5698                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
5699                    let prev_excerpt_id = excerpt_ids
5700                        .get(prev_excerpt_ix)
5701                        .cloned()
5702                        .unwrap_or_else(ExcerptId::max);
5703                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
5704
5705                    log::info!(
5706                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
5707                        excerpt_ix,
5708                        expected_excerpts.len(),
5709                        buffer_handle.read(cx).remote_id(),
5710                        buffer.text(),
5711                        start_ix..end_ix,
5712                        &buffer.text()[start_ix..end_ix]
5713                    );
5714
5715                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
5716                        multibuffer
5717                            .insert_excerpts_after(
5718                                prev_excerpt_id,
5719                                buffer_handle.clone(),
5720                                [ExcerptRange {
5721                                    context: start_ix..end_ix,
5722                                    primary: None,
5723                                }],
5724                                cx,
5725                            )
5726                            .pop()
5727                            .unwrap()
5728                    });
5729
5730                    excerpt_ids.insert(excerpt_ix, excerpt_id);
5731                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
5732                }
5733            }
5734
5735            if rng.gen_bool(0.3) {
5736                multibuffer.update(cx, |multibuffer, cx| {
5737                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
5738                })
5739            }
5740
5741            let snapshot = multibuffer.read(cx).snapshot(cx);
5742
5743            let mut excerpt_starts = Vec::new();
5744            let mut expected_text = String::new();
5745            let mut expected_buffer_rows = Vec::new();
5746            for (buffer, range) in &expected_excerpts {
5747                let buffer = buffer.read(cx);
5748                let buffer_range = range.to_offset(buffer);
5749
5750                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
5751                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
5752                expected_text.push('\n');
5753
5754                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
5755                    ..=buffer.offset_to_point(buffer_range.end).row;
5756                for row in buffer_row_range {
5757                    expected_buffer_rows.push(Some(row));
5758                }
5759            }
5760            // Remove final trailing newline.
5761            if !expected_excerpts.is_empty() {
5762                expected_text.pop();
5763            }
5764
5765            // Always report one buffer row
5766            if expected_buffer_rows.is_empty() {
5767                expected_buffer_rows.push(Some(0));
5768            }
5769
5770            assert_eq!(snapshot.text(), expected_text);
5771            log::info!("MultiBuffer text: {:?}", expected_text);
5772
5773            assert_eq!(
5774                snapshot.buffer_rows(MultiBufferRow(0)).collect::<Vec<_>>(),
5775                expected_buffer_rows,
5776            );
5777
5778            for _ in 0..5 {
5779                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
5780                assert_eq!(
5781                    snapshot
5782                        .buffer_rows(MultiBufferRow(start_row as u32))
5783                        .collect::<Vec<_>>(),
5784                    &expected_buffer_rows[start_row..],
5785                    "buffer_rows({})",
5786                    start_row
5787                );
5788            }
5789
5790            assert_eq!(
5791                snapshot.max_buffer_row().0,
5792                expected_buffer_rows.into_iter().flatten().max().unwrap()
5793            );
5794
5795            let mut excerpt_starts = excerpt_starts.into_iter();
5796            for (buffer, range) in &expected_excerpts {
5797                let buffer = buffer.read(cx);
5798                let buffer_id = buffer.remote_id();
5799                let buffer_range = range.to_offset(buffer);
5800                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
5801                let buffer_start_point_utf16 =
5802                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
5803
5804                let excerpt_start = excerpt_starts.next().unwrap();
5805                let mut offset = excerpt_start.len;
5806                let mut buffer_offset = buffer_range.start;
5807                let mut point = excerpt_start.lines;
5808                let mut buffer_point = buffer_start_point;
5809                let mut point_utf16 = excerpt_start.lines_utf16();
5810                let mut buffer_point_utf16 = buffer_start_point_utf16;
5811                for ch in buffer
5812                    .snapshot()
5813                    .chunks(buffer_range.clone(), false)
5814                    .flat_map(|c| c.text.chars())
5815                {
5816                    for _ in 0..ch.len_utf8() {
5817                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
5818                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
5819                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
5820                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
5821                        assert_eq!(
5822                            left_offset,
5823                            excerpt_start.len + (buffer_left_offset - buffer_range.start),
5824                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
5825                            offset,
5826                            buffer_id,
5827                            buffer_offset,
5828                        );
5829                        assert_eq!(
5830                            right_offset,
5831                            excerpt_start.len + (buffer_right_offset - buffer_range.start),
5832                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
5833                            offset,
5834                            buffer_id,
5835                            buffer_offset,
5836                        );
5837
5838                        let left_point = snapshot.clip_point(point, Bias::Left);
5839                        let right_point = snapshot.clip_point(point, Bias::Right);
5840                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
5841                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
5842                        assert_eq!(
5843                            left_point,
5844                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
5845                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
5846                            point,
5847                            buffer_id,
5848                            buffer_point,
5849                        );
5850                        assert_eq!(
5851                            right_point,
5852                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
5853                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
5854                            point,
5855                            buffer_id,
5856                            buffer_point,
5857                        );
5858
5859                        assert_eq!(
5860                            snapshot.point_to_offset(left_point),
5861                            left_offset,
5862                            "point_to_offset({:?})",
5863                            left_point,
5864                        );
5865                        assert_eq!(
5866                            snapshot.offset_to_point(left_offset),
5867                            left_point,
5868                            "offset_to_point({:?})",
5869                            left_offset,
5870                        );
5871
5872                        offset += 1;
5873                        buffer_offset += 1;
5874                        if ch == '\n' {
5875                            point += Point::new(1, 0);
5876                            buffer_point += Point::new(1, 0);
5877                        } else {
5878                            point += Point::new(0, 1);
5879                            buffer_point += Point::new(0, 1);
5880                        }
5881                    }
5882
5883                    for _ in 0..ch.len_utf16() {
5884                        let left_point_utf16 =
5885                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Left);
5886                        let right_point_utf16 =
5887                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Right);
5888                        let buffer_left_point_utf16 =
5889                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Left);
5890                        let buffer_right_point_utf16 =
5891                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Right);
5892                        assert_eq!(
5893                            left_point_utf16,
5894                            excerpt_start.lines_utf16()
5895                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
5896                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
5897                            point_utf16,
5898                            buffer_id,
5899                            buffer_point_utf16,
5900                        );
5901                        assert_eq!(
5902                            right_point_utf16,
5903                            excerpt_start.lines_utf16()
5904                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
5905                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
5906                            point_utf16,
5907                            buffer_id,
5908                            buffer_point_utf16,
5909                        );
5910
5911                        if ch == '\n' {
5912                            point_utf16 += PointUtf16::new(1, 0);
5913                            buffer_point_utf16 += PointUtf16::new(1, 0);
5914                        } else {
5915                            point_utf16 += PointUtf16::new(0, 1);
5916                            buffer_point_utf16 += PointUtf16::new(0, 1);
5917                        }
5918                    }
5919                }
5920            }
5921
5922            for (row, line) in expected_text.split('\n').enumerate() {
5923                assert_eq!(
5924                    snapshot.line_len(MultiBufferRow(row as u32)),
5925                    line.len() as u32,
5926                    "line_len({}).",
5927                    row
5928                );
5929            }
5930
5931            let text_rope = Rope::from(expected_text.as_str());
5932            for _ in 0..10 {
5933                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5934                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5935
5936                let text_for_range = snapshot
5937                    .text_for_range(start_ix..end_ix)
5938                    .collect::<String>();
5939                assert_eq!(
5940                    text_for_range,
5941                    &expected_text[start_ix..end_ix],
5942                    "incorrect text for range {:?}",
5943                    start_ix..end_ix
5944                );
5945
5946                let excerpted_buffer_ranges = multibuffer
5947                    .read(cx)
5948                    .range_to_buffer_ranges(start_ix..end_ix, cx);
5949                let excerpted_buffers_text = excerpted_buffer_ranges
5950                    .iter()
5951                    .map(|(buffer, buffer_range, _)| {
5952                        buffer
5953                            .read(cx)
5954                            .text_for_range(buffer_range.clone())
5955                            .collect::<String>()
5956                    })
5957                    .collect::<Vec<_>>()
5958                    .join("\n");
5959                assert_eq!(excerpted_buffers_text, text_for_range);
5960                if !expected_excerpts.is_empty() {
5961                    assert!(!excerpted_buffer_ranges.is_empty());
5962                }
5963
5964                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
5965                assert_eq!(
5966                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
5967                    expected_summary,
5968                    "incorrect summary for range {:?}",
5969                    start_ix..end_ix
5970                );
5971            }
5972
5973            // Anchor resolution
5974            let summaries = snapshot.summaries_for_anchors::<usize, _>(&anchors);
5975            assert_eq!(anchors.len(), summaries.len());
5976            for (anchor, resolved_offset) in anchors.iter().zip(summaries) {
5977                assert!(resolved_offset <= snapshot.len());
5978                assert_eq!(
5979                    snapshot.summary_for_anchor::<usize>(anchor),
5980                    resolved_offset
5981                );
5982            }
5983
5984            for _ in 0..10 {
5985                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5986                assert_eq!(
5987                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
5988                    expected_text[..end_ix].chars().rev().collect::<String>(),
5989                );
5990            }
5991
5992            for _ in 0..10 {
5993                let end_ix = rng.gen_range(0..=text_rope.len());
5994                let start_ix = rng.gen_range(0..=end_ix);
5995                assert_eq!(
5996                    snapshot
5997                        .bytes_in_range(start_ix..end_ix)
5998                        .flatten()
5999                        .copied()
6000                        .collect::<Vec<_>>(),
6001                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
6002                    "bytes_in_range({:?})",
6003                    start_ix..end_ix,
6004                );
6005            }
6006        }
6007
6008        let snapshot = multibuffer.read(cx).snapshot(cx);
6009        for (old_snapshot, subscription) in old_versions {
6010            let edits = subscription.consume().into_inner();
6011
6012            log::info!(
6013                "applying subscription edits to old text: {:?}: {:?}",
6014                old_snapshot.text(),
6015                edits,
6016            );
6017
6018            let mut text = old_snapshot.text();
6019            for edit in edits {
6020                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
6021                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
6022            }
6023            assert_eq!(text.to_string(), snapshot.text());
6024        }
6025    }
6026
6027    #[gpui::test]
6028    fn test_history(cx: &mut AppContext) {
6029        let test_settings = SettingsStore::test(cx);
6030        cx.set_global(test_settings);
6031
6032        let buffer_1 = cx.new_model(|cx| Buffer::local("1234", cx));
6033        let buffer_2 = cx.new_model(|cx| Buffer::local("5678", cx));
6034        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6035        let group_interval = multibuffer.read(cx).history.group_interval;
6036        multibuffer.update(cx, |multibuffer, cx| {
6037            multibuffer.push_excerpts(
6038                buffer_1.clone(),
6039                [ExcerptRange {
6040                    context: 0..buffer_1.read(cx).len(),
6041                    primary: None,
6042                }],
6043                cx,
6044            );
6045            multibuffer.push_excerpts(
6046                buffer_2.clone(),
6047                [ExcerptRange {
6048                    context: 0..buffer_2.read(cx).len(),
6049                    primary: None,
6050                }],
6051                cx,
6052            );
6053        });
6054
6055        let mut now = Instant::now();
6056
6057        multibuffer.update(cx, |multibuffer, cx| {
6058            let transaction_1 = multibuffer.start_transaction_at(now, cx).unwrap();
6059            multibuffer.edit(
6060                [
6061                    (Point::new(0, 0)..Point::new(0, 0), "A"),
6062                    (Point::new(1, 0)..Point::new(1, 0), "A"),
6063                ],
6064                None,
6065                cx,
6066            );
6067            multibuffer.edit(
6068                [
6069                    (Point::new(0, 1)..Point::new(0, 1), "B"),
6070                    (Point::new(1, 1)..Point::new(1, 1), "B"),
6071                ],
6072                None,
6073                cx,
6074            );
6075            multibuffer.end_transaction_at(now, cx);
6076            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6077
6078            // Verify edited ranges for transaction 1
6079            assert_eq!(
6080                multibuffer.edited_ranges_for_transaction(transaction_1, cx),
6081                &[
6082                    Point::new(0, 0)..Point::new(0, 2),
6083                    Point::new(1, 0)..Point::new(1, 2)
6084                ]
6085            );
6086
6087            // Edit buffer 1 through the multibuffer
6088            now += 2 * group_interval;
6089            multibuffer.start_transaction_at(now, cx);
6090            multibuffer.edit([(2..2, "C")], None, cx);
6091            multibuffer.end_transaction_at(now, cx);
6092            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
6093
6094            // Edit buffer 1 independently
6095            buffer_1.update(cx, |buffer_1, cx| {
6096                buffer_1.start_transaction_at(now);
6097                buffer_1.edit([(3..3, "D")], None, cx);
6098                buffer_1.end_transaction_at(now, cx);
6099
6100                now += 2 * group_interval;
6101                buffer_1.start_transaction_at(now);
6102                buffer_1.edit([(4..4, "E")], None, cx);
6103                buffer_1.end_transaction_at(now, cx);
6104            });
6105            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
6106
6107            // An undo in the multibuffer undoes the multibuffer transaction
6108            // and also any individual buffer edits that have occurred since
6109            // that transaction.
6110            multibuffer.undo(cx);
6111            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6112
6113            multibuffer.undo(cx);
6114            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6115
6116            multibuffer.redo(cx);
6117            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6118
6119            multibuffer.redo(cx);
6120            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
6121
6122            // Undo buffer 2 independently.
6123            buffer_2.update(cx, |buffer_2, cx| buffer_2.undo(cx));
6124            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\n5678");
6125
6126            // An undo in the multibuffer undoes the components of the
6127            // the last multibuffer transaction that are not already undone.
6128            multibuffer.undo(cx);
6129            assert_eq!(multibuffer.read(cx).text(), "AB1234\n5678");
6130
6131            multibuffer.undo(cx);
6132            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6133
6134            multibuffer.redo(cx);
6135            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
6136
6137            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
6138            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
6139
6140            // Redo stack gets cleared after an edit.
6141            now += 2 * group_interval;
6142            multibuffer.start_transaction_at(now, cx);
6143            multibuffer.edit([(0..0, "X")], None, cx);
6144            multibuffer.end_transaction_at(now, cx);
6145            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6146            multibuffer.redo(cx);
6147            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6148            multibuffer.undo(cx);
6149            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
6150            multibuffer.undo(cx);
6151            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6152
6153            // Transactions can be grouped manually.
6154            multibuffer.redo(cx);
6155            multibuffer.redo(cx);
6156            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6157            multibuffer.group_until_transaction(transaction_1, cx);
6158            multibuffer.undo(cx);
6159            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
6160            multibuffer.redo(cx);
6161            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
6162        });
6163    }
6164
6165    #[gpui::test]
6166    fn test_excerpts_in_ranges_no_ranges(cx: &mut AppContext) {
6167        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6168        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6169        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6170        multibuffer.update(cx, |multibuffer, cx| {
6171            multibuffer.push_excerpts(
6172                buffer_1.clone(),
6173                [ExcerptRange {
6174                    context: 0..buffer_1.read(cx).len(),
6175                    primary: None,
6176                }],
6177                cx,
6178            );
6179            multibuffer.push_excerpts(
6180                buffer_2.clone(),
6181                [ExcerptRange {
6182                    context: 0..buffer_2.read(cx).len(),
6183                    primary: None,
6184                }],
6185                cx,
6186            );
6187        });
6188
6189        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
6190
6191        let mut excerpts = snapshot.excerpts_in_ranges(iter::from_fn(|| None));
6192
6193        assert!(excerpts.next().is_none());
6194    }
6195
6196    fn validate_excerpts(
6197        actual: &Vec<(ExcerptId, BufferId, Range<Anchor>)>,
6198        expected: &Vec<(ExcerptId, BufferId, Range<Anchor>)>,
6199    ) {
6200        assert_eq!(actual.len(), expected.len());
6201
6202        actual
6203            .into_iter()
6204            .zip(expected)
6205            .map(|(actual, expected)| {
6206                assert_eq!(actual.0, expected.0);
6207                assert_eq!(actual.1, expected.1);
6208                assert_eq!(actual.2.start, expected.2.start);
6209                assert_eq!(actual.2.end, expected.2.end);
6210            })
6211            .collect_vec();
6212    }
6213
6214    fn map_range_from_excerpt(
6215        snapshot: &MultiBufferSnapshot,
6216        excerpt_id: ExcerptId,
6217        excerpt_buffer: &BufferSnapshot,
6218        range: Range<usize>,
6219    ) -> Range<Anchor> {
6220        snapshot
6221            .anchor_in_excerpt(excerpt_id, excerpt_buffer.anchor_before(range.start))
6222            .unwrap()
6223            ..snapshot
6224                .anchor_in_excerpt(excerpt_id, excerpt_buffer.anchor_after(range.end))
6225                .unwrap()
6226    }
6227
6228    fn make_expected_excerpt_info(
6229        snapshot: &MultiBufferSnapshot,
6230        cx: &mut AppContext,
6231        excerpt_id: ExcerptId,
6232        buffer: &Model<Buffer>,
6233        range: Range<usize>,
6234    ) -> (ExcerptId, BufferId, Range<Anchor>) {
6235        (
6236            excerpt_id,
6237            buffer.read(cx).remote_id(),
6238            map_range_from_excerpt(&snapshot, excerpt_id, &buffer.read(cx).snapshot(), range),
6239        )
6240    }
6241
6242    #[gpui::test]
6243    fn test_excerpts_in_ranges_range_inside_the_excerpt(cx: &mut AppContext) {
6244        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6245        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6246        let buffer_len = buffer_1.read(cx).len();
6247        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6248        let mut expected_excerpt_id = ExcerptId(0);
6249
6250        multibuffer.update(cx, |multibuffer, cx| {
6251            expected_excerpt_id = multibuffer.push_excerpts(
6252                buffer_1.clone(),
6253                [ExcerptRange {
6254                    context: 0..buffer_1.read(cx).len(),
6255                    primary: None,
6256                }],
6257                cx,
6258            )[0];
6259            multibuffer.push_excerpts(
6260                buffer_2.clone(),
6261                [ExcerptRange {
6262                    context: 0..buffer_2.read(cx).len(),
6263                    primary: None,
6264                }],
6265                cx,
6266            );
6267        });
6268
6269        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
6270
6271        let range = snapshot
6272            .anchor_in_excerpt(expected_excerpt_id, buffer_1.read(cx).anchor_before(1))
6273            .unwrap()
6274            ..snapshot
6275                .anchor_in_excerpt(
6276                    expected_excerpt_id,
6277                    buffer_1.read(cx).anchor_after(buffer_len / 2),
6278                )
6279                .unwrap();
6280
6281        let expected_excerpts = vec![make_expected_excerpt_info(
6282            &snapshot,
6283            cx,
6284            expected_excerpt_id,
6285            &buffer_1,
6286            1..(buffer_len / 2),
6287        )];
6288
6289        let excerpts = snapshot
6290            .excerpts_in_ranges(vec![range.clone()].into_iter())
6291            .map(|(excerpt_id, buffer, actual_range)| {
6292                (
6293                    excerpt_id,
6294                    buffer.remote_id(),
6295                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6296                )
6297            })
6298            .collect_vec();
6299
6300        validate_excerpts(&excerpts, &expected_excerpts);
6301    }
6302
6303    #[gpui::test]
6304    fn test_excerpts_in_ranges_range_crosses_excerpts_boundary(cx: &mut AppContext) {
6305        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6306        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6307        let buffer_len = buffer_1.read(cx).len();
6308        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6309        let mut excerpt_1_id = ExcerptId(0);
6310        let mut excerpt_2_id = ExcerptId(0);
6311
6312        multibuffer.update(cx, |multibuffer, cx| {
6313            excerpt_1_id = multibuffer.push_excerpts(
6314                buffer_1.clone(),
6315                [ExcerptRange {
6316                    context: 0..buffer_1.read(cx).len(),
6317                    primary: None,
6318                }],
6319                cx,
6320            )[0];
6321            excerpt_2_id = multibuffer.push_excerpts(
6322                buffer_2.clone(),
6323                [ExcerptRange {
6324                    context: 0..buffer_2.read(cx).len(),
6325                    primary: None,
6326                }],
6327                cx,
6328            )[0];
6329        });
6330
6331        let snapshot = multibuffer.read(cx).snapshot(cx);
6332
6333        let expected_range = snapshot
6334            .anchor_in_excerpt(
6335                excerpt_1_id,
6336                buffer_1.read(cx).anchor_before(buffer_len / 2),
6337            )
6338            .unwrap()
6339            ..snapshot
6340                .anchor_in_excerpt(excerpt_2_id, buffer_2.read(cx).anchor_after(buffer_len / 2))
6341                .unwrap();
6342
6343        let expected_excerpts = vec![
6344            make_expected_excerpt_info(
6345                &snapshot,
6346                cx,
6347                excerpt_1_id,
6348                &buffer_1,
6349                (buffer_len / 2)..buffer_len,
6350            ),
6351            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, 0..buffer_len / 2),
6352        ];
6353
6354        let excerpts = snapshot
6355            .excerpts_in_ranges(vec![expected_range.clone()].into_iter())
6356            .map(|(excerpt_id, buffer, actual_range)| {
6357                (
6358                    excerpt_id,
6359                    buffer.remote_id(),
6360                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6361                )
6362            })
6363            .collect_vec();
6364
6365        validate_excerpts(&excerpts, &expected_excerpts);
6366    }
6367
6368    #[gpui::test]
6369    fn test_excerpts_in_ranges_range_encloses_excerpt(cx: &mut AppContext) {
6370        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6371        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6372        let buffer_3 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'r'), cx));
6373        let buffer_len = buffer_1.read(cx).len();
6374        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6375        let mut excerpt_1_id = ExcerptId(0);
6376        let mut excerpt_2_id = ExcerptId(0);
6377        let mut excerpt_3_id = ExcerptId(0);
6378
6379        multibuffer.update(cx, |multibuffer, cx| {
6380            excerpt_1_id = multibuffer.push_excerpts(
6381                buffer_1.clone(),
6382                [ExcerptRange {
6383                    context: 0..buffer_1.read(cx).len(),
6384                    primary: None,
6385                }],
6386                cx,
6387            )[0];
6388            excerpt_2_id = multibuffer.push_excerpts(
6389                buffer_2.clone(),
6390                [ExcerptRange {
6391                    context: 0..buffer_2.read(cx).len(),
6392                    primary: None,
6393                }],
6394                cx,
6395            )[0];
6396            excerpt_3_id = multibuffer.push_excerpts(
6397                buffer_3.clone(),
6398                [ExcerptRange {
6399                    context: 0..buffer_3.read(cx).len(),
6400                    primary: None,
6401                }],
6402                cx,
6403            )[0];
6404        });
6405
6406        let snapshot = multibuffer.read(cx).snapshot(cx);
6407
6408        let expected_range = snapshot
6409            .anchor_in_excerpt(
6410                excerpt_1_id,
6411                buffer_1.read(cx).anchor_before(buffer_len / 2),
6412            )
6413            .unwrap()
6414            ..snapshot
6415                .anchor_in_excerpt(excerpt_3_id, buffer_3.read(cx).anchor_after(buffer_len / 2))
6416                .unwrap();
6417
6418        let expected_excerpts = vec![
6419            make_expected_excerpt_info(
6420                &snapshot,
6421                cx,
6422                excerpt_1_id,
6423                &buffer_1,
6424                (buffer_len / 2)..buffer_len,
6425            ),
6426            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, 0..buffer_len),
6427            make_expected_excerpt_info(&snapshot, cx, excerpt_3_id, &buffer_3, 0..buffer_len / 2),
6428        ];
6429
6430        let excerpts = snapshot
6431            .excerpts_in_ranges(vec![expected_range.clone()].into_iter())
6432            .map(|(excerpt_id, buffer, actual_range)| {
6433                (
6434                    excerpt_id,
6435                    buffer.remote_id(),
6436                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6437                )
6438            })
6439            .collect_vec();
6440
6441        validate_excerpts(&excerpts, &expected_excerpts);
6442    }
6443
6444    #[gpui::test]
6445    fn test_excerpts_in_ranges_multiple_ranges(cx: &mut AppContext) {
6446        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6447        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6448        let buffer_len = buffer_1.read(cx).len();
6449        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6450        let mut excerpt_1_id = ExcerptId(0);
6451        let mut excerpt_2_id = ExcerptId(0);
6452
6453        multibuffer.update(cx, |multibuffer, cx| {
6454            excerpt_1_id = multibuffer.push_excerpts(
6455                buffer_1.clone(),
6456                [ExcerptRange {
6457                    context: 0..buffer_1.read(cx).len(),
6458                    primary: None,
6459                }],
6460                cx,
6461            )[0];
6462            excerpt_2_id = multibuffer.push_excerpts(
6463                buffer_2.clone(),
6464                [ExcerptRange {
6465                    context: 0..buffer_2.read(cx).len(),
6466                    primary: None,
6467                }],
6468                cx,
6469            )[0];
6470        });
6471
6472        let snapshot = multibuffer.read(cx).snapshot(cx);
6473
6474        let ranges = vec![
6475            1..(buffer_len / 4),
6476            (buffer_len / 3)..(buffer_len / 2),
6477            (buffer_len / 4 * 3)..(buffer_len),
6478        ];
6479
6480        let expected_excerpts = ranges
6481            .iter()
6482            .map(|range| {
6483                make_expected_excerpt_info(&snapshot, cx, excerpt_1_id, &buffer_1, range.clone())
6484            })
6485            .collect_vec();
6486
6487        let ranges = ranges.into_iter().map(|range| {
6488            map_range_from_excerpt(
6489                &snapshot,
6490                excerpt_1_id,
6491                &buffer_1.read(cx).snapshot(),
6492                range,
6493            )
6494        });
6495
6496        let excerpts = snapshot
6497            .excerpts_in_ranges(ranges)
6498            .map(|(excerpt_id, buffer, actual_range)| {
6499                (
6500                    excerpt_id,
6501                    buffer.remote_id(),
6502                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6503                )
6504            })
6505            .collect_vec();
6506
6507        validate_excerpts(&excerpts, &expected_excerpts);
6508    }
6509
6510    #[gpui::test]
6511    fn test_excerpts_in_ranges_range_ends_at_excerpt_end(cx: &mut AppContext) {
6512        let buffer_1 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'a'), cx));
6513        let buffer_2 = cx.new_model(|cx| Buffer::local(sample_text(6, 6, 'g'), cx));
6514        let buffer_len = buffer_1.read(cx).len();
6515        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
6516        let mut excerpt_1_id = ExcerptId(0);
6517        let mut excerpt_2_id = ExcerptId(0);
6518
6519        multibuffer.update(cx, |multibuffer, cx| {
6520            excerpt_1_id = multibuffer.push_excerpts(
6521                buffer_1.clone(),
6522                [ExcerptRange {
6523                    context: 0..buffer_1.read(cx).len(),
6524                    primary: None,
6525                }],
6526                cx,
6527            )[0];
6528            excerpt_2_id = multibuffer.push_excerpts(
6529                buffer_2.clone(),
6530                [ExcerptRange {
6531                    context: 0..buffer_2.read(cx).len(),
6532                    primary: None,
6533                }],
6534                cx,
6535            )[0];
6536        });
6537
6538        let snapshot = multibuffer.read(cx).snapshot(cx);
6539
6540        let ranges = [0..buffer_len, (buffer_len / 3)..(buffer_len / 2)];
6541
6542        let expected_excerpts = vec![
6543            make_expected_excerpt_info(&snapshot, cx, excerpt_1_id, &buffer_1, ranges[0].clone()),
6544            make_expected_excerpt_info(&snapshot, cx, excerpt_2_id, &buffer_2, ranges[1].clone()),
6545        ];
6546
6547        let ranges = [
6548            map_range_from_excerpt(
6549                &snapshot,
6550                excerpt_1_id,
6551                &buffer_1.read(cx).snapshot(),
6552                ranges[0].clone(),
6553            ),
6554            map_range_from_excerpt(
6555                &snapshot,
6556                excerpt_2_id,
6557                &buffer_2.read(cx).snapshot(),
6558                ranges[1].clone(),
6559            ),
6560        ];
6561
6562        let excerpts = snapshot
6563            .excerpts_in_ranges(ranges.into_iter())
6564            .map(|(excerpt_id, buffer, actual_range)| {
6565                (
6566                    excerpt_id,
6567                    buffer.remote_id(),
6568                    map_range_from_excerpt(&snapshot, excerpt_id, buffer, actual_range),
6569                )
6570            })
6571            .collect_vec();
6572
6573        validate_excerpts(&excerpts, &expected_excerpts);
6574    }
6575}