multi_buffer.rs

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