multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod position;
   6mod transaction;
   7
   8use self::transaction::History;
   9
  10pub use anchor::{Anchor, AnchorRangeExt, Offset};
  11pub use position::{TypedOffset, TypedPoint, TypedRow};
  12
  13use anyhow::{Result, anyhow};
  14use buffer_diff::{
  15    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  16    DiffHunkStatusKind,
  17};
  18use clock::ReplicaId;
  19use collections::{BTreeMap, Bound, HashMap, HashSet};
  20use gpui::{App, Context, Entity, EntityId, EventEmitter};
  21use itertools::Itertools;
  22use language::{
  23    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  24    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState, File,
  25    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  26    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  27    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  28    language_settings::{LanguageSettings, language_settings},
  29};
  30
  31#[cfg(any(test, feature = "test-support"))]
  32use gpui::AppContext as _;
  33
  34use rope::DimensionPair;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, Ref, RefCell},
  41    cmp,
  42    collections::VecDeque,
  43    fmt,
  44    future::Future,
  45    io,
  46    iter::{self, FromIterator},
  47    mem,
  48    ops::{Range, RangeBounds, Sub},
  49    rc::Rc,
  50    str,
  51    sync::Arc,
  52    time::Duration,
  53};
  54use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  55use text::{
  56    BufferId, Edit, LineIndent, TextSummary,
  57    locator::Locator,
  58    subscription::{Subscription, Topic},
  59};
  60use theme::SyntaxTheme;
  61use util::{RangeExt, post_inc};
  62
  63pub use self::path_key::PathKey;
  64
  65#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  66pub struct ExcerptId(u32);
  67
  68/// One or more [`Buffers`](Buffer) being edited in a single view.
  69///
  70/// See <https://zed.dev/features#multi-buffers>
  71pub struct MultiBuffer {
  72    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  73    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  74    snapshot: RefCell<MultiBufferSnapshot>,
  75    /// Contains the state of the buffers being edited
  76    buffers: HashMap<BufferId, BufferState>,
  77    /// Mapping from path keys to their excerpts.
  78    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  79    /// Mapping from excerpt IDs to their path key.
  80    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  81    /// Mapping from buffer IDs to their diff states
  82    diffs: HashMap<BufferId, DiffState>,
  83    subscriptions: Topic,
  84    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  85    singleton: bool,
  86    /// The history of the multi-buffer.
  87    history: History,
  88    /// The explicit title of the multi-buffer.
  89    /// If `None`, it will be derived from the underlying path or content.
  90    title: Option<String>,
  91    /// The writing capability of the multi-buffer.
  92    capability: Capability,
  93    buffer_changed_since_sync: Rc<Cell<bool>>,
  94}
  95
  96#[derive(Clone, Debug, PartialEq, Eq)]
  97pub enum Event {
  98    ExcerptsAdded {
  99        buffer: Entity<Buffer>,
 100        predecessor: ExcerptId,
 101        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 102    },
 103    ExcerptsRemoved {
 104        ids: Vec<ExcerptId>,
 105        removed_buffer_ids: Vec<BufferId>,
 106    },
 107    ExcerptsExpanded {
 108        ids: Vec<ExcerptId>,
 109    },
 110    ExcerptsEdited {
 111        excerpt_ids: Vec<ExcerptId>,
 112        buffer_ids: Vec<BufferId>,
 113    },
 114    DiffHunksToggled,
 115    Edited {
 116        edited_buffer: Option<Entity<Buffer>>,
 117    },
 118    TransactionUndone {
 119        transaction_id: TransactionId,
 120    },
 121    Reloaded,
 122    LanguageChanged(BufferId),
 123    Reparsed(BufferId),
 124    Saved,
 125    FileHandleChanged,
 126    DirtyChanged,
 127    DiagnosticsUpdated,
 128    BufferDiffChanged,
 129}
 130
 131// ex1
 132// line4 of buffer1
 133// ex2
 134// line17 of buffer2
 135//
 136// in multibuffer coordinates, Point::new(1, 0)
 137
 138/// A diff hunk, representing a range of consequent lines in a multibuffer.
 139#[derive(Debug, Clone, PartialEq, Eq)]
 140pub struct MultiBufferDiffHunk {
 141    /// The row range in the multibuffer where this diff hunk appears.
 142    pub row_range: Range<MultiBufferRow>,
 143    /// The buffer ID that this hunk belongs to.
 144    pub buffer_id: BufferId,
 145    /// The range of the underlying buffer that this hunk corresponds to.
 146    pub buffer_range: Range<text::Anchor>,
 147    /// The excerpt that contains the diff hunk.
 148    pub excerpt_id: ExcerptId,
 149    /// The range within the buffer's diff base that this hunk corresponds to.
 150    pub diff_base_byte_range: Range<usize>,
 151    /// Whether or not this hunk also appears in the 'secondary diff'.
 152    pub secondary_status: DiffHunkSecondaryStatus,
 153}
 154
 155impl MultiBufferDiffHunk {
 156    pub fn status(&self) -> DiffHunkStatus {
 157        let kind = if self.buffer_range.start == self.buffer_range.end {
 158            DiffHunkStatusKind::Deleted
 159        } else if self.diff_base_byte_range.is_empty() {
 160            DiffHunkStatusKind::Added
 161        } else {
 162            DiffHunkStatusKind::Modified
 163        };
 164        DiffHunkStatus {
 165            kind,
 166            secondary: self.secondary_status,
 167        }
 168    }
 169
 170    pub fn is_created_file(&self) -> bool {
 171        self.diff_base_byte_range == (0..0)
 172            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 173    }
 174
 175    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 176        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 177        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 178        start..end
 179    }
 180}
 181
 182pub type MultiBufferPoint = Point;
 183type ExcerptOffset = TypedOffset<Excerpt>;
 184type ExcerptPoint = TypedPoint<Excerpt>;
 185
 186#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 187#[serde(transparent)]
 188pub struct MultiBufferRow(pub u32);
 189
 190impl MultiBufferRow {
 191    pub const MIN: Self = Self(0);
 192    pub const MAX: Self = Self(u32::MAX);
 193}
 194
 195impl std::ops::Add<usize> for MultiBufferRow {
 196    type Output = Self;
 197
 198    fn add(self, rhs: usize) -> Self::Output {
 199        MultiBufferRow(self.0 + rhs as u32)
 200    }
 201}
 202
 203pub trait ToOffset: 'static + fmt::Debug {
 204    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 205    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 206}
 207
 208pub trait ToPoint: 'static + fmt::Debug {
 209    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 210    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 211}
 212
 213struct BufferState {
 214    buffer: Entity<Buffer>,
 215    last_version: RefCell<clock::Global>,
 216    last_non_text_state_update_count: Cell<usize>,
 217    excerpts: Vec<Locator>,
 218    _subscriptions: [gpui::Subscription; 2],
 219}
 220
 221struct DiffState {
 222    diff: Entity<BufferDiff>,
 223    _subscription: gpui::Subscription,
 224}
 225
 226impl DiffState {
 227    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 228        DiffState {
 229            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 230                BufferDiffEvent::DiffChanged { changed_range } => {
 231                    if let Some(changed_range) = changed_range.clone() {
 232                        this.buffer_diff_changed(diff, changed_range, cx)
 233                    }
 234                    cx.emit(Event::BufferDiffChanged);
 235                }
 236                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 237                _ => {}
 238            }),
 239            diff,
 240        }
 241    }
 242}
 243
 244/// The contents of a [`MultiBuffer`] at a single point in time.
 245#[derive(Clone, Default)]
 246pub struct MultiBufferSnapshot {
 247    excerpts: SumTree<Excerpt>,
 248    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 249    diff_transforms: SumTree<DiffTransform>,
 250    non_text_state_update_count: usize,
 251    edit_count: usize,
 252    is_dirty: bool,
 253    has_deleted_file: bool,
 254    has_conflict: bool,
 255    /// immutable fields
 256    singleton: bool,
 257    excerpt_ids: SumTree<ExcerptIdMapping>,
 258    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 259    trailing_excerpt_update_count: usize,
 260    all_diff_hunks_expanded: bool,
 261    show_headers: bool,
 262}
 263
 264/// A section of text in a [`MultiBuffer`] that may or may not have changed relative to some "base
 265/// text".
 266///
 267/// Despite having two variants, there are conceptually three different states:
 268/// - `BufferContent { inserted_hunk_info: None, ..}` represents a region of text that has not
 269///   changed, relative to the base text.
 270/// - `BufferContent { inserted_hunk_info: Some(info), ..}` represents a region of text that has
 271///   been added, relative to the base text.
 272/// - `DeletedHunk` represents a region of text that has been deleted, relative to the base text.
 273///
 274/// The [`TextSummaries`](TextSummary) refer to either:
 275/// - the buffer text (`multi_buffer.buffers[buffer_id].buffer.snapshot`)
 276/// - the base text (`multi_buffer.diffs[buffer_id].diff.inner.base_text`)
 277///
 278/// The multibuffer tries to maintain an invariant that: "no two consecutive [`DiffTransform`]s can
 279/// be merged". In other words, if two consecutive [`DiffTransform`]s *could* be merged, they will
 280/// be.
 281#[derive(Debug, Clone)]
 282enum DiffTransform {
 283    BufferContent {
 284        summary: TextSummary,
 285        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 286    },
 287    DeletedHunk {
 288        summary: TextSummary,
 289        buffer_id: BufferId,
 290        hunk_info: DiffTransformHunkInfo,
 291        base_text_byte_range: Range<usize>,
 292        has_trailing_newline: bool,
 293    },
 294}
 295
 296#[derive(Clone, Copy, Debug)]
 297struct DiffTransformHunkInfo {
 298    excerpt_id: ExcerptId,
 299    hunk_start_anchor: text::Anchor,
 300    hunk_secondary_status: DiffHunkSecondaryStatus,
 301}
 302
 303impl Eq for DiffTransformHunkInfo {}
 304
 305impl PartialEq for DiffTransformHunkInfo {
 306    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 307        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 308    }
 309}
 310
 311impl std::hash::Hash for DiffTransformHunkInfo {
 312    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 313        self.excerpt_id.hash(state);
 314        self.hunk_start_anchor.hash(state);
 315    }
 316}
 317
 318#[derive(Clone)]
 319pub struct ExcerptInfo {
 320    pub id: ExcerptId,
 321    pub buffer: BufferSnapshot,
 322    pub buffer_id: BufferId,
 323    pub range: ExcerptRange<text::Anchor>,
 324    pub end_row: MultiBufferRow,
 325}
 326
 327impl std::fmt::Debug for ExcerptInfo {
 328    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 329        f.debug_struct(type_name::<Self>())
 330            .field("id", &self.id)
 331            .field("buffer_id", &self.buffer_id)
 332            .field("path", &self.buffer.file().map(|f| f.path()))
 333            .field("range", &self.range)
 334            .finish()
 335    }
 336}
 337
 338/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 339#[derive(Debug)]
 340pub struct ExcerptBoundary {
 341    pub prev: Option<ExcerptInfo>,
 342    pub next: ExcerptInfo,
 343    /// The row in the `MultiBuffer` where the boundary is located
 344    pub row: MultiBufferRow,
 345}
 346
 347impl ExcerptBoundary {
 348    pub fn starts_new_buffer(&self) -> bool {
 349        match (self.prev.as_ref(), &self.next) {
 350            (None, _) => true,
 351            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 352        }
 353    }
 354}
 355
 356#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 357pub struct ExpandInfo {
 358    pub direction: ExpandExcerptDirection,
 359    pub excerpt_id: ExcerptId,
 360}
 361
 362#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 363pub struct RowInfo {
 364    pub buffer_id: Option<BufferId>,
 365    pub buffer_row: Option<u32>,
 366    pub multibuffer_row: Option<MultiBufferRow>,
 367    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 368    pub expand_info: Option<ExpandInfo>,
 369}
 370
 371/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 372#[derive(Clone)]
 373struct Excerpt {
 374    /// The unique identifier for this excerpt
 375    id: ExcerptId,
 376    /// The location of the excerpt in the [`MultiBuffer`]
 377    locator: Locator,
 378    /// The buffer being excerpted
 379    buffer_id: BufferId,
 380    /// A snapshot of the buffer being excerpted
 381    buffer: BufferSnapshot,
 382    /// The range of the buffer to be shown in the excerpt
 383    range: ExcerptRange<text::Anchor>,
 384    /// The last row in the excerpted slice of the buffer
 385    max_buffer_row: BufferRow,
 386    /// A summary of the text in the excerpt
 387    text_summary: TextSummary,
 388    has_trailing_newline: bool,
 389}
 390
 391/// A public view into an `Excerpt` in a [`MultiBuffer`].
 392///
 393/// Contains methods for getting the [`Buffer`] of the excerpt,
 394/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 395#[derive(Clone)]
 396pub struct MultiBufferExcerpt<'a> {
 397    excerpt: &'a Excerpt,
 398    diff_transforms: sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<usize>>,
 399    offset: usize,
 400    excerpt_offset: ExcerptDimension<usize>,
 401    buffer_offset: usize,
 402}
 403
 404#[derive(Clone, Debug)]
 405struct ExcerptIdMapping {
 406    id: ExcerptId,
 407    locator: Locator,
 408}
 409
 410/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 411/// These ranges are relative to the buffer itself
 412#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 413pub struct ExcerptRange<T> {
 414    /// The full range of text to be shown in the excerpt.
 415    pub context: Range<T>,
 416    /// The primary range of text to be highlighted in the excerpt.
 417    /// In a multi-buffer search, this would be the text that matched the search
 418    pub primary: Range<T>,
 419}
 420
 421impl<T: Clone> ExcerptRange<T> {
 422    pub fn new(context: Range<T>) -> Self {
 423        Self {
 424            context: context.clone(),
 425            primary: context,
 426        }
 427    }
 428}
 429
 430#[derive(Clone, Debug, Default)]
 431pub struct ExcerptSummary {
 432    excerpt_id: ExcerptId,
 433    /// The location of the last [`Excerpt`] being summarized
 434    excerpt_locator: Locator,
 435    widest_line_number: u32,
 436    text: TextSummary,
 437}
 438
 439#[derive(Debug, Clone)]
 440pub struct DiffTransformSummary {
 441    input: TextSummary,
 442    output: TextSummary,
 443}
 444
 445#[derive(Clone)]
 446pub struct MultiBufferRows<'a> {
 447    point: Point,
 448    is_empty: bool,
 449    is_singleton: bool,
 450    cursor: MultiBufferCursor<'a, Point>,
 451}
 452
 453pub struct MultiBufferChunks<'a> {
 454    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 455    diff_transforms: Cursor<'a, 'static, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 456    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 457    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 458    buffer_chunk: Option<Chunk<'a>>,
 459    range: Range<usize>,
 460    excerpt_offset_range: Range<ExcerptOffset>,
 461    excerpt_chunks: Option<ExcerptChunks<'a>>,
 462    language_aware: bool,
 463}
 464
 465pub struct ReversedMultiBufferChunks<'a> {
 466    cursor: MultiBufferCursor<'a, usize>,
 467    current_chunks: Option<rope::Chunks<'a>>,
 468    start: usize,
 469    offset: usize,
 470}
 471
 472pub struct MultiBufferBytes<'a> {
 473    range: Range<usize>,
 474    cursor: MultiBufferCursor<'a, usize>,
 475    excerpt_bytes: Option<text::Bytes<'a>>,
 476    has_trailing_newline: bool,
 477    chunk: &'a [u8],
 478}
 479
 480pub struct ReversedMultiBufferBytes<'a> {
 481    range: Range<usize>,
 482    chunks: ReversedMultiBufferChunks<'a>,
 483    chunk: &'a [u8],
 484}
 485
 486#[derive(Clone)]
 487struct DiffTransforms<D> {
 488    output_dimension: OutputDimension<D>,
 489    excerpt_dimension: ExcerptDimension<D>,
 490}
 491
 492impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 493    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 494        Self {
 495            output_dimension: OutputDimension::zero(cx),
 496            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 497                cx,
 498            ),
 499        }
 500    }
 501
 502    fn add_summary(
 503        &mut self,
 504        summary: &'a DiffTransformSummary,
 505        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 506    ) {
 507        self.output_dimension.add_summary(summary, cx);
 508        self.excerpt_dimension.add_summary(summary, cx);
 509    }
 510}
 511
 512#[derive(Clone)]
 513struct MultiBufferCursor<'a, D: TextDimension> {
 514    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<D>>,
 515    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<D>>,
 516    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 517    cached_region: Option<MultiBufferRegion<'a, D>>,
 518}
 519
 520#[derive(Clone)]
 521struct MultiBufferRegion<'a, D: TextDimension> {
 522    buffer: &'a BufferSnapshot,
 523    is_main_buffer: bool,
 524    diff_hunk_status: Option<DiffHunkStatus>,
 525    excerpt: &'a Excerpt,
 526    buffer_range: Range<D>,
 527    range: Range<D>,
 528    has_trailing_newline: bool,
 529}
 530
 531impl<'a, D: TextDimension + fmt::Debug> fmt::Debug for MultiBufferRegion<'a, D> {
 532    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 533        f.debug_struct("MultiBufferRegion")
 534            .field("is_main_buffer", &self.is_main_buffer)
 535            .field("diff_hunk_status", &self.diff_hunk_status)
 536            .field("excerpt", &self.excerpt)
 537            .field("buffer_range", &self.buffer_range)
 538            .field("range", &self.range)
 539            .field("has_trailing_newline", &self.has_trailing_newline)
 540            .finish()
 541    }
 542}
 543
 544struct ExcerptChunks<'a> {
 545    excerpt_id: ExcerptId,
 546    content_chunks: BufferChunks<'a>,
 547    has_footer: bool,
 548}
 549
 550#[derive(Debug)]
 551struct BufferEdit {
 552    range: Range<usize>,
 553    new_text: Arc<str>,
 554    is_insertion: bool,
 555    original_indent_column: Option<u32>,
 556    excerpt_id: ExcerptId,
 557}
 558
 559#[derive(Clone, Copy, Debug, PartialEq)]
 560enum DiffChangeKind {
 561    BufferEdited,
 562    DiffUpdated { base_changed: bool },
 563    ExpandOrCollapseHunks { expand: bool },
 564}
 565
 566#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 567pub enum ExpandExcerptDirection {
 568    Up,
 569    Down,
 570    UpAndDown,
 571}
 572
 573impl ExpandExcerptDirection {
 574    pub fn should_expand_up(&self) -> bool {
 575        match self {
 576            ExpandExcerptDirection::Up => true,
 577            ExpandExcerptDirection::Down => false,
 578            ExpandExcerptDirection::UpAndDown => true,
 579        }
 580    }
 581
 582    pub fn should_expand_down(&self) -> bool {
 583        match self {
 584            ExpandExcerptDirection::Up => false,
 585            ExpandExcerptDirection::Down => true,
 586            ExpandExcerptDirection::UpAndDown => true,
 587        }
 588    }
 589}
 590
 591#[derive(Clone, Debug, PartialEq)]
 592pub struct IndentGuide {
 593    pub buffer_id: BufferId,
 594    pub start_row: MultiBufferRow,
 595    pub end_row: MultiBufferRow,
 596    pub depth: u32,
 597    pub tab_size: u32,
 598    pub settings: IndentGuideSettings,
 599}
 600
 601impl IndentGuide {
 602    pub fn indent_level(&self) -> u32 {
 603        self.depth * self.tab_size
 604    }
 605}
 606
 607impl MultiBuffer {
 608    pub fn new(capability: Capability) -> Self {
 609        Self::new_(
 610            capability,
 611            MultiBufferSnapshot {
 612                show_headers: true,
 613                ..MultiBufferSnapshot::default()
 614            },
 615        )
 616    }
 617
 618    pub fn without_headers(capability: Capability) -> Self {
 619        Self::new_(capability, Default::default())
 620    }
 621
 622    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 623        let mut this = Self::new_(
 624            buffer.read(cx).capability(),
 625            MultiBufferSnapshot {
 626                singleton: true,
 627                ..MultiBufferSnapshot::default()
 628            },
 629        );
 630        this.singleton = true;
 631        this.push_excerpts(
 632            buffer,
 633            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 634            cx,
 635        );
 636        this
 637    }
 638
 639    #[inline]
 640    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
 641        Self {
 642            snapshot: RefCell::new(snapshot),
 643            buffers: Default::default(),
 644            diffs: HashMap::default(),
 645            subscriptions: Topic::default(),
 646            singleton: false,
 647            capability,
 648            title: None,
 649            excerpts_by_path: Default::default(),
 650            paths_by_excerpt: Default::default(),
 651            buffer_changed_since_sync: Default::default(),
 652            history: History::default(),
 653        }
 654    }
 655
 656    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 657        let mut buffers = HashMap::default();
 658        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 659        for (buffer_id, buffer_state) in self.buffers.iter() {
 660            buffer_state.buffer.update(new_cx, |buffer, _| {
 661                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 662            });
 663            buffers.insert(
 664                *buffer_id,
 665                BufferState {
 666                    buffer: buffer_state.buffer.clone(),
 667                    last_version: buffer_state.last_version.clone(),
 668                    last_non_text_state_update_count: buffer_state
 669                        .last_non_text_state_update_count
 670                        .clone(),
 671                    excerpts: buffer_state.excerpts.clone(),
 672                    _subscriptions: [
 673                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 674                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 675                    ],
 676                },
 677            );
 678        }
 679        let mut diff_bases = HashMap::default();
 680        for (buffer_id, diff) in self.diffs.iter() {
 681            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 682        }
 683        Self {
 684            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 685            buffers: buffers,
 686            excerpts_by_path: Default::default(),
 687            paths_by_excerpt: Default::default(),
 688            diffs: diff_bases,
 689            subscriptions: Default::default(),
 690            singleton: self.singleton,
 691            capability: self.capability,
 692            history: self.history.clone(),
 693            title: self.title.clone(),
 694            buffer_changed_since_sync,
 695        }
 696    }
 697
 698    pub fn set_group_interval(&mut self, group_interval: Duration) {
 699        self.history.set_group_interval(group_interval);
 700    }
 701
 702    pub fn with_title(mut self, title: String) -> Self {
 703        self.title = Some(title);
 704        self
 705    }
 706
 707    pub fn read_only(&self) -> bool {
 708        self.capability == Capability::ReadOnly
 709    }
 710
 711    /// Returns an up-to-date snapshot of the MultiBuffer.
 712    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 713        self.sync(cx);
 714        self.snapshot.borrow().clone()
 715    }
 716
 717    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 718        self.sync(cx);
 719        self.snapshot.borrow()
 720    }
 721
 722    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 723        if self.singleton {
 724            Some(self.buffers.values().next().unwrap().buffer.clone())
 725        } else {
 726            None
 727        }
 728    }
 729
 730    pub fn is_singleton(&self) -> bool {
 731        self.singleton
 732    }
 733
 734    pub fn subscribe(&mut self) -> Subscription {
 735        self.subscriptions.subscribe()
 736    }
 737
 738    pub fn is_dirty(&self, cx: &App) -> bool {
 739        self.read(cx).is_dirty()
 740    }
 741
 742    pub fn has_deleted_file(&self, cx: &App) -> bool {
 743        self.read(cx).has_deleted_file()
 744    }
 745
 746    pub fn has_conflict(&self, cx: &App) -> bool {
 747        self.read(cx).has_conflict()
 748    }
 749
 750    // The `is_empty` signature doesn't match what clippy expects
 751    #[allow(clippy::len_without_is_empty)]
 752    pub fn len(&self, cx: &App) -> usize {
 753        self.read(cx).len()
 754    }
 755
 756    pub fn is_empty(&self) -> bool {
 757        self.buffers.is_empty()
 758    }
 759
 760    pub fn edit<I, S, T>(
 761        &mut self,
 762        edits: I,
 763        autoindent_mode: Option<AutoindentMode>,
 764        cx: &mut Context<Self>,
 765    ) where
 766        I: IntoIterator<Item = (Range<S>, T)>,
 767        S: ToOffset,
 768        T: Into<Arc<str>>,
 769    {
 770        if self.read_only() || self.buffers.is_empty() {
 771            return;
 772        }
 773        self.sync_mut(cx);
 774        let edits = edits
 775            .into_iter()
 776            .map(|(range, new_text)| {
 777                let mut range = range.start.to_offset(self.snapshot.get_mut())
 778                    ..range.end.to_offset(self.snapshot.get_mut());
 779                if range.start > range.end {
 780                    mem::swap(&mut range.start, &mut range.end);
 781                }
 782                (range, new_text.into())
 783            })
 784            .collect::<Vec<_>>();
 785
 786        return edit_internal(self, edits, autoindent_mode, cx);
 787
 788        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 789        fn edit_internal(
 790            this: &mut MultiBuffer,
 791            edits: Vec<(Range<usize>, Arc<str>)>,
 792            mut autoindent_mode: Option<AutoindentMode>,
 793            cx: &mut Context<MultiBuffer>,
 794        ) {
 795            let original_indent_columns = match &mut autoindent_mode {
 796                Some(AutoindentMode::Block {
 797                    original_indent_columns,
 798                }) => mem::take(original_indent_columns),
 799                _ => Default::default(),
 800            };
 801
 802            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
 803                edits,
 804                this.snapshot.get_mut(),
 805                &original_indent_columns,
 806            );
 807
 808            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 809            for (buffer_id, mut edits) in buffer_edits {
 810                buffer_ids.push(buffer_id);
 811                edits.sort_by_key(|edit| edit.range.start);
 812                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
 813                    let mut edits = edits.into_iter().peekable();
 814                    let mut insertions = Vec::new();
 815                    let mut original_indent_columns = Vec::new();
 816                    let mut deletions = Vec::new();
 817                    let empty_str: Arc<str> = Arc::default();
 818                    while let Some(BufferEdit {
 819                        mut range,
 820                        mut new_text,
 821                        mut is_insertion,
 822                        original_indent_column,
 823                        excerpt_id,
 824                    }) = edits.next()
 825                    {
 826                        while let Some(BufferEdit {
 827                            range: next_range,
 828                            is_insertion: next_is_insertion,
 829                            new_text: next_new_text,
 830                            excerpt_id: next_excerpt_id,
 831                            ..
 832                        }) = edits.peek()
 833                        {
 834                            if range.end >= next_range.start {
 835                                range.end = cmp::max(next_range.end, range.end);
 836                                is_insertion |= *next_is_insertion;
 837                                if excerpt_id == *next_excerpt_id {
 838                                    new_text = format!("{new_text}{next_new_text}").into();
 839                                }
 840                                edits.next();
 841                            } else {
 842                                break;
 843                            }
 844                        }
 845
 846                        if is_insertion {
 847                            original_indent_columns.push(original_indent_column);
 848                            insertions.push((
 849                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 850                                new_text.clone(),
 851                            ));
 852                        } else if !range.is_empty() {
 853                            deletions.push((
 854                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 855                                empty_str.clone(),
 856                            ));
 857                        }
 858                    }
 859
 860                    let deletion_autoindent_mode =
 861                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 862                            Some(AutoindentMode::Block {
 863                                original_indent_columns: Default::default(),
 864                            })
 865                        } else {
 866                            autoindent_mode.clone()
 867                        };
 868                    let insertion_autoindent_mode =
 869                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 870                            Some(AutoindentMode::Block {
 871                                original_indent_columns,
 872                            })
 873                        } else {
 874                            autoindent_mode.clone()
 875                        };
 876
 877                    buffer.edit(deletions, deletion_autoindent_mode, cx);
 878                    buffer.edit(insertions, insertion_autoindent_mode, cx);
 879                })
 880            }
 881
 882            cx.emit(Event::ExcerptsEdited {
 883                excerpt_ids: edited_excerpt_ids,
 884                buffer_ids,
 885            });
 886        }
 887    }
 888
 889    fn convert_edits_to_buffer_edits(
 890        edits: Vec<(Range<usize>, Arc<str>)>,
 891        snapshot: &MultiBufferSnapshot,
 892        original_indent_columns: &[Option<u32>],
 893    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 894        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 895        let mut edited_excerpt_ids = Vec::new();
 896        let mut cursor = snapshot.cursor::<usize>();
 897        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 898            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 899
 900            cursor.seek(&range.start);
 901            let mut start_region = cursor.region().expect("start offset out of bounds");
 902            if !start_region.is_main_buffer {
 903                cursor.next();
 904                if let Some(region) = cursor.region() {
 905                    start_region = region;
 906                } else {
 907                    continue;
 908                }
 909            }
 910
 911            if range.end < start_region.range.start {
 912                continue;
 913            }
 914
 915            if range.end > start_region.range.end {
 916                cursor.seek_forward(&range.end);
 917            }
 918            let mut end_region = cursor.region().expect("end offset out of bounds");
 919            if !end_region.is_main_buffer {
 920                cursor.prev();
 921                if let Some(region) = cursor.region() {
 922                    end_region = region;
 923                } else {
 924                    continue;
 925                }
 926            }
 927
 928            if range.start > end_region.range.end {
 929                continue;
 930            }
 931
 932            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 933            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 934            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 935                .min(start_region.buffer_range.end);
 936            let buffer_end =
 937                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 938
 939            if start_region.excerpt.id == end_region.excerpt.id {
 940                if start_region.is_main_buffer {
 941                    edited_excerpt_ids.push(start_region.excerpt.id);
 942                    buffer_edits
 943                        .entry(start_region.buffer.remote_id())
 944                        .or_default()
 945                        .push(BufferEdit {
 946                            range: buffer_start..buffer_end,
 947                            new_text,
 948                            is_insertion: true,
 949                            original_indent_column,
 950                            excerpt_id: start_region.excerpt.id,
 951                        });
 952                }
 953            } else {
 954                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 955                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 956                if start_region.is_main_buffer {
 957                    edited_excerpt_ids.push(start_region.excerpt.id);
 958                    buffer_edits
 959                        .entry(start_region.buffer.remote_id())
 960                        .or_default()
 961                        .push(BufferEdit {
 962                            range: start_excerpt_range,
 963                            new_text: new_text.clone(),
 964                            is_insertion: true,
 965                            original_indent_column,
 966                            excerpt_id: start_region.excerpt.id,
 967                        });
 968                }
 969                if end_region.is_main_buffer {
 970                    edited_excerpt_ids.push(end_region.excerpt.id);
 971                    buffer_edits
 972                        .entry(end_region.buffer.remote_id())
 973                        .or_default()
 974                        .push(BufferEdit {
 975                            range: end_excerpt_range,
 976                            new_text: new_text.clone(),
 977                            is_insertion: false,
 978                            original_indent_column,
 979                            excerpt_id: end_region.excerpt.id,
 980                        });
 981                }
 982
 983                cursor.seek(&range.start);
 984                cursor.next_excerpt();
 985                while let Some(region) = cursor.region() {
 986                    if region.excerpt.id == end_region.excerpt.id {
 987                        break;
 988                    }
 989                    if region.is_main_buffer {
 990                        edited_excerpt_ids.push(region.excerpt.id);
 991                        buffer_edits
 992                            .entry(region.buffer.remote_id())
 993                            .or_default()
 994                            .push(BufferEdit {
 995                                range: region.buffer_range,
 996                                new_text: new_text.clone(),
 997                                is_insertion: false,
 998                                original_indent_column,
 999                                excerpt_id: region.excerpt.id,
1000                            });
1001                    }
1002                    cursor.next_excerpt();
1003                }
1004            }
1005        }
1006        (buffer_edits, edited_excerpt_ids)
1007    }
1008
1009    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1010    where
1011        I: IntoIterator<Item = Range<S>>,
1012        S: ToOffset,
1013    {
1014        if self.read_only() || self.buffers.is_empty() {
1015            return;
1016        }
1017        self.sync_mut(cx);
1018        let empty = Arc::<str>::from("");
1019        let edits = ranges
1020            .into_iter()
1021            .map(|range| {
1022                let mut range = range.start.to_offset(self.snapshot.get_mut())
1023                    ..range.end.to_offset(&self.snapshot.get_mut());
1024                if range.start > range.end {
1025                    mem::swap(&mut range.start, &mut range.end);
1026                }
1027                (range, empty.clone())
1028            })
1029            .collect::<Vec<_>>();
1030
1031        return autoindent_ranges_internal(self, edits, cx);
1032
1033        fn autoindent_ranges_internal(
1034            this: &mut MultiBuffer,
1035            edits: Vec<(Range<usize>, Arc<str>)>,
1036            cx: &mut Context<MultiBuffer>,
1037        ) {
1038            let (buffer_edits, edited_excerpt_ids) =
1039                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1040
1041            let mut buffer_ids = Vec::new();
1042            for (buffer_id, mut edits) in buffer_edits {
1043                buffer_ids.push(buffer_id);
1044                edits.sort_unstable_by_key(|edit| edit.range.start);
1045
1046                let mut ranges: Vec<Range<usize>> = Vec::new();
1047                for edit in edits {
1048                    if let Some(last_range) = ranges.last_mut()
1049                        && edit.range.start <= last_range.end
1050                    {
1051                        last_range.end = last_range.end.max(edit.range.end);
1052                        continue;
1053                    }
1054                    ranges.push(edit.range);
1055                }
1056
1057                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1058                    buffer.autoindent_ranges(ranges, cx);
1059                })
1060            }
1061
1062            cx.emit(Event::ExcerptsEdited {
1063                excerpt_ids: edited_excerpt_ids,
1064                buffer_ids,
1065            });
1066        }
1067    }
1068
1069    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1070    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1071    /// Panics if the given position is invalid.
1072    pub fn insert_empty_line(
1073        &mut self,
1074        position: impl ToPoint,
1075        space_above: bool,
1076        space_below: bool,
1077        cx: &mut Context<Self>,
1078    ) -> Point {
1079        let multibuffer_point = position.to_point(&self.read(cx));
1080        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1081        self.start_transaction(cx);
1082        let empty_line_start = buffer.update(cx, |buffer, cx| {
1083            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1084        });
1085        self.end_transaction(cx);
1086        multibuffer_point + (empty_line_start - buffer_point)
1087    }
1088
1089    pub fn set_active_selections(
1090        &self,
1091        selections: &[Selection<Anchor>],
1092        line_mode: bool,
1093        cursor_shape: CursorShape,
1094        cx: &mut Context<Self>,
1095    ) {
1096        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1097            Default::default();
1098        let snapshot = self.read(cx);
1099        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1100        for selection in selections {
1101            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1102            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1103
1104            cursor.seek(&Some(start_locator), Bias::Left);
1105            while let Some(excerpt) = cursor.item()
1106                && excerpt.locator <= *end_locator
1107            {
1108                let mut start = excerpt.range.context.start;
1109                let mut end = excerpt.range.context.end;
1110                if excerpt.id == selection.start.excerpt_id {
1111                    start = selection.start.text_anchor;
1112                }
1113                if excerpt.id == selection.end.excerpt_id {
1114                    end = selection.end.text_anchor;
1115                }
1116                selections_by_buffer
1117                    .entry(excerpt.buffer_id)
1118                    .or_default()
1119                    .push(Selection {
1120                        id: selection.id,
1121                        start,
1122                        end,
1123                        reversed: selection.reversed,
1124                        goal: selection.goal,
1125                    });
1126
1127                cursor.next();
1128            }
1129        }
1130
1131        for (buffer_id, buffer_state) in self.buffers.iter() {
1132            if !selections_by_buffer.contains_key(buffer_id) {
1133                buffer_state
1134                    .buffer
1135                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1136            }
1137        }
1138
1139        for (buffer_id, mut selections) in selections_by_buffer {
1140            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1141                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1142                let mut selections = selections.into_iter().peekable();
1143                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1144                    let mut selection = selections.next()?;
1145                    while let Some(next_selection) = selections.peek() {
1146                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1147                            let next_selection = selections.next().unwrap();
1148                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1149                                selection.end = next_selection.end;
1150                            }
1151                        } else {
1152                            break;
1153                        }
1154                    }
1155                    Some(selection)
1156                }));
1157                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1158            });
1159        }
1160    }
1161
1162    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1163        for buffer in self.buffers.values() {
1164            buffer
1165                .buffer
1166                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1167        }
1168    }
1169
1170    pub fn push_excerpts<O>(
1171        &mut self,
1172        buffer: Entity<Buffer>,
1173        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1174        cx: &mut Context<Self>,
1175    ) -> Vec<ExcerptId>
1176    where
1177        O: text::ToOffset,
1178    {
1179        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1180    }
1181
1182    fn merge_excerpt_ranges<'a>(
1183        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1184    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1185        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1186        let mut counts: Vec<usize> = Vec::new();
1187        for range in expanded_ranges {
1188            if let Some(last_range) = merged_ranges.last_mut() {
1189                debug_assert!(
1190                    last_range.context.start <= range.context.start,
1191                    "Last range: {last_range:?} Range: {range:?}"
1192                );
1193                if last_range.context.end >= range.context.start
1194                    || last_range.context.end.row + 1 == range.context.start.row
1195                {
1196                    last_range.context.end = range.context.end.max(last_range.context.end);
1197                    *counts.last_mut().unwrap() += 1;
1198                    continue;
1199                }
1200            }
1201            merged_ranges.push(range.clone());
1202            counts.push(1);
1203        }
1204        (merged_ranges, counts)
1205    }
1206
1207    pub fn insert_excerpts_after<O>(
1208        &mut self,
1209        prev_excerpt_id: ExcerptId,
1210        buffer: Entity<Buffer>,
1211        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1212        cx: &mut Context<Self>,
1213    ) -> Vec<ExcerptId>
1214    where
1215        O: text::ToOffset,
1216    {
1217        let mut ids = Vec::new();
1218        let mut next_excerpt_id =
1219            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1220                last_entry.id.0 + 1
1221            } else {
1222                1
1223            };
1224        self.insert_excerpts_with_ids_after(
1225            prev_excerpt_id,
1226            buffer,
1227            ranges.into_iter().map(|range| {
1228                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1229                ids.push(id);
1230                (id, range)
1231            }),
1232            cx,
1233        );
1234        ids
1235    }
1236
1237    pub fn insert_excerpts_with_ids_after<O>(
1238        &mut self,
1239        prev_excerpt_id: ExcerptId,
1240        buffer: Entity<Buffer>,
1241        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1242        cx: &mut Context<Self>,
1243    ) where
1244        O: text::ToOffset,
1245    {
1246        assert_eq!(self.history.transaction_depth(), 0);
1247        let mut ranges = ranges.into_iter().peekable();
1248        if ranges.peek().is_none() {
1249            return Default::default();
1250        }
1251
1252        self.sync_mut(cx);
1253
1254        let buffer_snapshot = buffer.read(cx).snapshot();
1255        let buffer_id = buffer_snapshot.remote_id();
1256
1257        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1258            self.buffer_changed_since_sync.replace(true);
1259            buffer.update(cx, |buffer, _| {
1260                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1261            });
1262            BufferState {
1263                last_version: RefCell::new(buffer_snapshot.version().clone()),
1264                last_non_text_state_update_count: Cell::new(
1265                    buffer_snapshot.non_text_state_update_count(),
1266                ),
1267                excerpts: Default::default(),
1268                _subscriptions: [
1269                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1270                    cx.subscribe(&buffer, Self::on_buffer_event),
1271                ],
1272                buffer: buffer.clone(),
1273            }
1274        });
1275
1276        let mut snapshot = self.snapshot.get_mut();
1277
1278        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1279        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1280        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1281        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1282        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1283
1284        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1285        new_excerpts.update_last(
1286            |excerpt| {
1287                excerpt.has_trailing_newline = true;
1288            },
1289            (),
1290        );
1291
1292        let next_locator = if let Some(excerpt) = cursor.item() {
1293            excerpt.locator.clone()
1294        } else {
1295            Locator::max()
1296        };
1297
1298        let mut excerpts = Vec::new();
1299        while let Some((id, range)) = ranges.next() {
1300            let locator = Locator::between(&prev_locator, &next_locator);
1301            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1302                buffer_state.excerpts.insert(ix, locator.clone());
1303            }
1304            let range = ExcerptRange {
1305                context: buffer_snapshot.anchor_before(&range.context.start)
1306                    ..buffer_snapshot.anchor_after(&range.context.end),
1307                primary: buffer_snapshot.anchor_before(&range.primary.start)
1308                    ..buffer_snapshot.anchor_after(&range.primary.end),
1309            };
1310            excerpts.push((id, range.clone()));
1311            let excerpt = Excerpt::new(
1312                id,
1313                locator.clone(),
1314                buffer_id,
1315                buffer_snapshot.clone(),
1316                range,
1317                ranges.peek().is_some() || cursor.item().is_some(),
1318            );
1319            new_excerpts.push(excerpt, ());
1320            prev_locator = locator.clone();
1321
1322            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1323                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1324            }
1325            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1326        }
1327
1328        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1329
1330        let suffix = cursor.suffix();
1331        let changed_trailing_excerpt = suffix.is_empty();
1332        new_excerpts.append(suffix, ());
1333        drop(cursor);
1334        snapshot.excerpts = new_excerpts;
1335        snapshot.excerpt_ids = new_excerpt_ids;
1336        if changed_trailing_excerpt {
1337            snapshot.trailing_excerpt_update_count += 1;
1338        }
1339
1340        let edits = Self::sync_diff_transforms(
1341            &mut snapshot,
1342            vec![Edit {
1343                old: edit_start..edit_start,
1344                new: edit_start..edit_end,
1345            }],
1346            DiffChangeKind::BufferEdited,
1347        );
1348        if !edits.is_empty() {
1349            self.subscriptions.publish(edits);
1350        }
1351
1352        cx.emit(Event::Edited {
1353            edited_buffer: None,
1354        });
1355        cx.emit(Event::ExcerptsAdded {
1356            buffer,
1357            predecessor: prev_excerpt_id,
1358            excerpts,
1359        });
1360        cx.notify();
1361    }
1362
1363    pub fn clear(&mut self, cx: &mut Context<Self>) {
1364        self.sync_mut(cx);
1365        let ids = self.excerpt_ids();
1366        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1367        self.excerpts_by_path.clear();
1368        self.paths_by_excerpt.clear();
1369        let MultiBufferSnapshot {
1370            excerpts,
1371            diffs: _,
1372            diff_transforms: _,
1373            non_text_state_update_count: _,
1374            edit_count: _,
1375            is_dirty,
1376            has_deleted_file,
1377            has_conflict,
1378            singleton: _,
1379            excerpt_ids: _,
1380            replaced_excerpts,
1381            trailing_excerpt_update_count,
1382            all_diff_hunks_expanded: _,
1383            show_headers: _,
1384        } = self.snapshot.get_mut();
1385        let start = ExcerptOffset::new(0);
1386        let prev_len = ExcerptOffset::new(excerpts.summary().text.len);
1387        *excerpts = Default::default();
1388        *trailing_excerpt_update_count += 1;
1389        *is_dirty = false;
1390        *has_deleted_file = false;
1391        *has_conflict = false;
1392        replaced_excerpts.clear();
1393
1394        let edits = Self::sync_diff_transforms(
1395            self.snapshot.get_mut(),
1396            vec![Edit {
1397                old: start..prev_len,
1398                new: start..start,
1399            }],
1400            DiffChangeKind::BufferEdited,
1401        );
1402        if !edits.is_empty() {
1403            self.subscriptions.publish(edits);
1404        }
1405        cx.emit(Event::Edited {
1406            edited_buffer: None,
1407        });
1408        cx.emit(Event::ExcerptsRemoved {
1409            ids,
1410            removed_buffer_ids,
1411        });
1412        cx.notify();
1413    }
1414
1415    pub fn excerpts_for_buffer(
1416        &self,
1417        buffer_id: BufferId,
1418        cx: &App,
1419    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1420        let mut excerpts = Vec::new();
1421        let snapshot = self.read(cx);
1422        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1423        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1424            for locator in locators {
1425                cursor.seek_forward(&Some(locator), Bias::Left);
1426                if let Some(excerpt) = cursor.item()
1427                    && excerpt.locator == *locator
1428                {
1429                    excerpts.push((excerpt.id, excerpt.range.clone()));
1430                }
1431            }
1432        }
1433
1434        excerpts
1435    }
1436
1437    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1438        let snapshot = self.read(cx);
1439        let mut excerpts = snapshot
1440            .excerpts
1441            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
1442        let mut diff_transforms = snapshot
1443            .diff_transforms
1444            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
1445        diff_transforms.next();
1446        let locators = self
1447            .buffers
1448            .get(&buffer_id)
1449            .into_iter()
1450            .flat_map(|state| &state.excerpts);
1451        let mut result = Vec::new();
1452        for locator in locators {
1453            excerpts.seek_forward(&Some(locator), Bias::Left);
1454            if let Some(excerpt) = excerpts.item()
1455                && excerpt.locator == *locator
1456            {
1457                let excerpt_start = excerpts.start().1.clone();
1458                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1459
1460                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1461                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
1462                let start = diff_transforms.start().1.0 + overshoot;
1463
1464                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1465                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
1466                let end = diff_transforms.start().1.0 + overshoot;
1467
1468                result.push(start..end)
1469            }
1470        }
1471        result
1472    }
1473
1474    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1475        self.snapshot
1476            .borrow()
1477            .excerpts
1478            .iter()
1479            .map(|entry| entry.buffer_id)
1480            .collect()
1481    }
1482
1483    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1484        self.snapshot
1485            .borrow()
1486            .excerpts
1487            .iter()
1488            .map(|entry| entry.id)
1489            .collect()
1490    }
1491
1492    pub fn excerpt_containing(
1493        &self,
1494        position: impl ToOffset,
1495        cx: &App,
1496    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1497        let snapshot = self.read(cx);
1498        let offset = position.to_offset(&snapshot);
1499
1500        let mut cursor = snapshot.cursor::<usize>();
1501        cursor.seek(&offset);
1502        cursor
1503            .excerpt()
1504            .or_else(|| snapshot.excerpts.last())
1505            .map(|excerpt| {
1506                (
1507                    excerpt.id,
1508                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1509                    excerpt.range.context.clone(),
1510                )
1511            })
1512    }
1513
1514    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1515        if let Some(buffer_id) = anchor.buffer_id {
1516            self.buffer(buffer_id)
1517        } else {
1518            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
1519            Some(buffer)
1520        }
1521    }
1522
1523    // If point is at the end of the buffer, the last excerpt is returned
1524    pub fn point_to_buffer_offset<T: ToOffset>(
1525        &self,
1526        point: T,
1527        cx: &App,
1528    ) -> Option<(Entity<Buffer>, usize)> {
1529        let snapshot = self.read(cx);
1530        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1531        Some((
1532            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1533            offset,
1534        ))
1535    }
1536
1537    // If point is at the end of the buffer, the last excerpt is returned
1538    pub fn point_to_buffer_point<T: ToPoint>(
1539        &self,
1540        point: T,
1541        cx: &App,
1542    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1543        let snapshot = self.read(cx);
1544        let (buffer, point, is_main_buffer) =
1545            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1546        Some((
1547            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1548            point,
1549            is_main_buffer,
1550        ))
1551    }
1552
1553    pub fn buffer_point_to_anchor(
1554        &self,
1555        buffer: &Entity<Buffer>,
1556        point: Point,
1557        cx: &App,
1558    ) -> Option<Anchor> {
1559        let mut found = None;
1560        let snapshot = buffer.read(cx).snapshot();
1561        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1562            let start = range.context.start.to_point(&snapshot);
1563            let end = range.context.end.to_point(&snapshot);
1564            if start <= point && point < end {
1565                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1566                break;
1567            }
1568            if point < start {
1569                found = Some((start, excerpt_id));
1570            }
1571            if point > end {
1572                found = Some((end, excerpt_id));
1573            }
1574        }
1575
1576        found.map(|(point, excerpt_id)| {
1577            let text_anchor = snapshot.anchor_after(point);
1578            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1579        })
1580    }
1581
1582    pub fn remove_excerpts(
1583        &mut self,
1584        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1585        cx: &mut Context<Self>,
1586    ) {
1587        self.sync_mut(cx);
1588        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1589        if ids.is_empty() {
1590            return;
1591        }
1592        self.buffer_changed_since_sync.replace(true);
1593
1594        let mut snapshot = self.snapshot.get_mut();
1595        let mut new_excerpts = SumTree::default();
1596        let mut cursor = snapshot
1597            .excerpts
1598            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1599        let mut edits = Vec::new();
1600        let mut excerpt_ids = ids.iter().copied().peekable();
1601        let mut removed_buffer_ids = Vec::new();
1602
1603        while let Some(excerpt_id) = excerpt_ids.next() {
1604            self.paths_by_excerpt.remove(&excerpt_id);
1605            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1606            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1607            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
1608
1609            if let Some(mut excerpt) = cursor.item() {
1610                if excerpt.id != excerpt_id {
1611                    continue;
1612                }
1613                let mut old_start = cursor.start().1;
1614
1615                // Skip over the removed excerpt.
1616                'remove_excerpts: loop {
1617                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
1618                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1619                        if buffer_state.excerpts.is_empty() {
1620                            log::debug!(
1621                                "removing buffer and diff for buffer {}",
1622                                excerpt.buffer_id
1623                            );
1624                            self.buffers.remove(&excerpt.buffer_id);
1625                            removed_buffer_ids.push(excerpt.buffer_id);
1626                        }
1627                    }
1628                    cursor.next();
1629
1630                    // Skip over any subsequent excerpts that are also removed.
1631                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1632                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1633                        if let Some(next_excerpt) = cursor.item()
1634                            && next_excerpt.locator == *next_locator
1635                        {
1636                            excerpt_ids.next();
1637                            excerpt = next_excerpt;
1638                            continue 'remove_excerpts;
1639                        }
1640                    }
1641
1642                    break;
1643                }
1644
1645                // When removing the last excerpt, remove the trailing newline from
1646                // the previous excerpt.
1647                if cursor.item().is_none() && old_start.value > 0 {
1648                    old_start.value -= 1;
1649                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
1650                }
1651
1652                // Push an edit for the removal of this run of excerpts.
1653                let old_end = cursor.start().1;
1654                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1655                edits.push(Edit {
1656                    old: old_start..old_end,
1657                    new: new_start..new_start,
1658                });
1659            }
1660        }
1661        let suffix = cursor.suffix();
1662        let changed_trailing_excerpt = suffix.is_empty();
1663        new_excerpts.append(suffix, ());
1664        drop(cursor);
1665        snapshot.excerpts = new_excerpts;
1666        for buffer_id in &removed_buffer_ids {
1667            self.diffs.remove(buffer_id);
1668            snapshot.diffs.remove(buffer_id);
1669        }
1670
1671        if changed_trailing_excerpt {
1672            snapshot.trailing_excerpt_update_count += 1;
1673        }
1674
1675        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
1676        if !edits.is_empty() {
1677            self.subscriptions.publish(edits);
1678        }
1679        cx.emit(Event::Edited {
1680            edited_buffer: None,
1681        });
1682        cx.emit(Event::ExcerptsRemoved {
1683            ids,
1684            removed_buffer_ids,
1685        });
1686        cx.notify();
1687    }
1688
1689    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1690        &self,
1691        anchors: Anchors,
1692        cx: &mut Context<Self>,
1693    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1694        let mut error = None;
1695        let mut futures = Vec::new();
1696        for anchor in anchors {
1697            if let Some(buffer_id) = anchor.buffer_id {
1698                if let Some(buffer) = self.buffers.get(&buffer_id) {
1699                    buffer.buffer.update(cx, |buffer, _| {
1700                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1701                    });
1702                } else {
1703                    error = Some(anyhow!(
1704                        "buffer {buffer_id} is not part of this multi-buffer"
1705                    ));
1706                    break;
1707                }
1708            }
1709        }
1710        async move {
1711            if let Some(error) = error {
1712                Err(error)?;
1713            }
1714            for future in futures {
1715                future.await?;
1716            }
1717            Ok(())
1718        }
1719    }
1720
1721    pub fn text_anchor_for_position<T: ToOffset>(
1722        &self,
1723        position: T,
1724        cx: &App,
1725    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1726        let snapshot = self.read(cx);
1727        let anchor = snapshot.anchor_before(position);
1728        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
1729        Some((buffer, anchor.text_anchor))
1730    }
1731
1732    fn on_buffer_event(
1733        &mut self,
1734        buffer: Entity<Buffer>,
1735        event: &language::BufferEvent,
1736        cx: &mut Context<Self>,
1737    ) {
1738        use language::BufferEvent;
1739        cx.emit(match event {
1740            BufferEvent::Edited => Event::Edited {
1741                edited_buffer: Some(buffer),
1742            },
1743            BufferEvent::DirtyChanged => Event::DirtyChanged,
1744            BufferEvent::Saved => Event::Saved,
1745            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1746            BufferEvent::Reloaded => Event::Reloaded,
1747            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1748            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1749            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1750            BufferEvent::CapabilityChanged => {
1751                self.capability = buffer.read(cx).capability();
1752                return;
1753            }
1754            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1755        });
1756    }
1757
1758    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1759        let diff = diff.read(cx);
1760        let buffer_id = diff.buffer_id;
1761        let diff = diff.snapshot(cx);
1762        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
1763    }
1764
1765    fn buffer_diff_changed(
1766        &mut self,
1767        diff: Entity<BufferDiff>,
1768        range: Range<text::Anchor>,
1769        cx: &mut Context<Self>,
1770    ) {
1771        self.sync_mut(cx);
1772
1773        let diff = diff.read(cx);
1774        let buffer_id = diff.buffer_id;
1775        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
1776            return;
1777        };
1778        self.buffer_changed_since_sync.replace(true);
1779
1780        let buffer = buffer_state.buffer.read(cx);
1781        let diff_change_range = range.to_offset(buffer);
1782
1783        let new_diff = diff.snapshot(cx);
1784        let mut snapshot = self.snapshot.get_mut();
1785        let base_text_changed = snapshot
1786            .diffs
1787            .get(&buffer_id)
1788            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
1789
1790        snapshot.diffs.insert(buffer_id, new_diff);
1791
1792        let mut excerpt_edits = Vec::new();
1793        for locator in &buffer_state.excerpts {
1794            let mut cursor = snapshot
1795                .excerpts
1796                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1797            cursor.seek_forward(&Some(locator), Bias::Left);
1798            if let Some(excerpt) = cursor.item()
1799                && excerpt.locator == *locator
1800            {
1801                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
1802                if diff_change_range.end < excerpt_buffer_range.start
1803                    || diff_change_range.start > excerpt_buffer_range.end
1804                {
1805                    continue;
1806                }
1807                let excerpt_start = cursor.start().1;
1808                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
1809                let diff_change_start_in_excerpt = ExcerptOffset::new(
1810                    diff_change_range
1811                        .start
1812                        .saturating_sub(excerpt_buffer_range.start),
1813                );
1814                let diff_change_end_in_excerpt = ExcerptOffset::new(
1815                    diff_change_range
1816                        .end
1817                        .saturating_sub(excerpt_buffer_range.start),
1818                );
1819                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
1820                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
1821                excerpt_edits.push(Edit {
1822                    old: edit_start..edit_end,
1823                    new: edit_start..edit_end,
1824                });
1825            }
1826        }
1827
1828        let edits = Self::sync_diff_transforms(
1829            &mut snapshot,
1830            excerpt_edits,
1831            DiffChangeKind::DiffUpdated {
1832                base_changed: base_text_changed,
1833            },
1834        );
1835        if !edits.is_empty() {
1836            self.subscriptions.publish(edits);
1837        }
1838        cx.emit(Event::Edited {
1839            edited_buffer: None,
1840        });
1841    }
1842
1843    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
1844        self.buffers
1845            .values()
1846            .map(|state| state.buffer.clone())
1847            .collect()
1848    }
1849
1850    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
1851        self.buffers.keys().copied().collect()
1852    }
1853
1854    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
1855        self.buffers
1856            .get(&buffer_id)
1857            .map(|state| state.buffer.clone())
1858    }
1859
1860    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
1861        self.point_to_buffer_offset(point, cx)
1862            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
1863    }
1864
1865    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
1866        let buffer_id = self
1867            .snapshot
1868            .borrow()
1869            .excerpts
1870            .first()
1871            .map(|excerpt| excerpt.buffer.remote_id());
1872        buffer_id
1873            .and_then(|buffer_id| self.buffer(buffer_id))
1874            .map(|buffer| {
1875                let buffer = buffer.read(cx);
1876                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
1877            })
1878            .unwrap_or_else(move || self.language_settings_at(0, cx))
1879    }
1880
1881    pub fn language_settings_at<'a, T: ToOffset>(
1882        &'a self,
1883        point: T,
1884        cx: &'a App,
1885    ) -> Cow<'a, LanguageSettings> {
1886        let mut language = None;
1887        let mut file = None;
1888        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
1889            let buffer = buffer.read(cx);
1890            language = buffer.language_at(offset);
1891            file = buffer.file();
1892        }
1893        language_settings(language.map(|l| l.name()), file, cx)
1894    }
1895
1896    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
1897        self.buffers.values().for_each(|state| f(&state.buffer))
1898    }
1899
1900    pub fn explicit_title(&self) -> Option<&str> {
1901        self.title.as_deref()
1902    }
1903
1904    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
1905        if let Some(title) = self.title.as_ref() {
1906            return title.into();
1907        }
1908
1909        if let Some(buffer) = self.as_singleton() {
1910            let buffer = buffer.read(cx);
1911
1912            if let Some(file) = buffer.file() {
1913                return file.file_name(cx).into();
1914            }
1915
1916            if let Some(title) = self.buffer_content_title(buffer) {
1917                return title;
1918            }
1919        };
1920
1921        "untitled".into()
1922    }
1923
1924    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
1925        let mut is_leading_whitespace = true;
1926        let mut count = 0;
1927        let mut prev_was_space = false;
1928        let mut title = String::new();
1929
1930        for ch in buffer.snapshot().chars() {
1931            if is_leading_whitespace && ch.is_whitespace() {
1932                continue;
1933            }
1934
1935            is_leading_whitespace = false;
1936
1937            if ch == '\n' || count >= 40 {
1938                break;
1939            }
1940
1941            if ch.is_whitespace() {
1942                if !prev_was_space {
1943                    title.push(' ');
1944                    count += 1;
1945                    prev_was_space = true;
1946                }
1947            } else {
1948                title.push(ch);
1949                count += 1;
1950                prev_was_space = false;
1951            }
1952        }
1953
1954        let title = title.trim_end().to_string();
1955
1956        if title.is_empty() {
1957            return None;
1958        }
1959
1960        Some(title.into())
1961    }
1962
1963    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
1964        self.title = Some(title);
1965        cx.notify();
1966    }
1967
1968    /// Preserve preview tabs containing this multibuffer until additional edits occur.
1969    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
1970        for buffer_state in self.buffers.values() {
1971            buffer_state
1972                .buffer
1973                .update(cx, |buffer, _cx| buffer.refresh_preview());
1974        }
1975    }
1976
1977    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
1978    pub fn preserve_preview(&self, cx: &App) -> bool {
1979        self.buffers
1980            .values()
1981            .all(|state| state.buffer.read(cx).preserve_preview())
1982    }
1983
1984    #[cfg(any(test, feature = "test-support"))]
1985    pub fn is_parsing(&self, cx: &App) -> bool {
1986        self.as_singleton().unwrap().read(cx).is_parsing()
1987    }
1988
1989    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1990        let buffer_id = diff.read(cx).buffer_id;
1991        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
1992        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
1993    }
1994
1995    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
1996        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
1997    }
1998
1999    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2000        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2001    }
2002
2003    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2004        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2005    }
2006
2007    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2008        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2009        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2010    }
2011
2012    pub fn all_diff_hunks_expanded(&self) -> bool {
2013        self.snapshot.borrow().all_diff_hunks_expanded
2014    }
2015
2016    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2017        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2018        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2019    }
2020
2021    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2022        self.read(cx)
2023            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2024            .nth(1)
2025            .is_some()
2026    }
2027
2028    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2029        let snapshot = self.read(cx);
2030        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2031        let offset_range = range.to_offset(&snapshot);
2032        cursor.seek(&offset_range.start, Bias::Left);
2033        while let Some(item) = cursor.item() {
2034            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2035                break;
2036            }
2037            if item.hunk_info().is_some() {
2038                return true;
2039            }
2040            cursor.next();
2041        }
2042        false
2043    }
2044
2045    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2046        let snapshot = self.read(cx);
2047        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2048        for range in ranges {
2049            let range = range.to_point(&snapshot);
2050            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2051            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2052            let start = start.saturating_sub(1);
2053            let end = snapshot.len().min(end + 1);
2054            cursor.seek(&start, Bias::Right);
2055            while let Some(item) = cursor.item() {
2056                if *cursor.start() >= end {
2057                    break;
2058                }
2059                if item.hunk_info().is_some() {
2060                    return true;
2061                }
2062                cursor.next();
2063            }
2064        }
2065        false
2066    }
2067
2068    pub fn expand_or_collapse_diff_hunks_inner(
2069        &mut self,
2070        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2071        expand: bool,
2072        cx: &mut Context<Self>,
2073    ) {
2074        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2075            return;
2076        }
2077        self.sync_mut(cx);
2078        let mut snapshot = self.snapshot.get_mut();
2079        let mut excerpt_edits = Vec::new();
2080        let mut last_hunk_row = None;
2081        for (range, end_excerpt_id) in ranges {
2082            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2083                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2084                    continue;
2085                }
2086                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2087                    continue;
2088                }
2089                let start = Anchor::in_buffer(
2090                    diff_hunk.excerpt_id,
2091                    diff_hunk.buffer_id,
2092                    diff_hunk.buffer_range.start,
2093                );
2094                let end = Anchor::in_buffer(
2095                    diff_hunk.excerpt_id,
2096                    diff_hunk.buffer_id,
2097                    diff_hunk.buffer_range.end,
2098                );
2099                let start = snapshot.excerpt_offset_for_anchor(&start);
2100                let end = snapshot.excerpt_offset_for_anchor(&end);
2101                last_hunk_row = Some(diff_hunk.row_range.start);
2102                excerpt_edits.push(text::Edit {
2103                    old: start..end,
2104                    new: start..end,
2105                });
2106            }
2107        }
2108
2109        let edits = Self::sync_diff_transforms(
2110            &mut snapshot,
2111            excerpt_edits,
2112            DiffChangeKind::ExpandOrCollapseHunks { expand },
2113        );
2114        if !edits.is_empty() {
2115            self.subscriptions.publish(edits);
2116        }
2117        cx.emit(Event::DiffHunksToggled);
2118        cx.emit(Event::Edited {
2119            edited_buffer: None,
2120        });
2121    }
2122
2123    pub fn expand_or_collapse_diff_hunks(
2124        &mut self,
2125        ranges: Vec<Range<Anchor>>,
2126        expand: bool,
2127        cx: &mut Context<Self>,
2128    ) {
2129        let snapshot = self.snapshot.borrow().clone();
2130        let ranges = ranges.iter().map(move |range| {
2131            let end_excerpt_id = range.end.excerpt_id;
2132            let range = range.to_point(&snapshot);
2133            let mut peek_end = range.end;
2134            if range.end.row < snapshot.max_row().0 {
2135                peek_end = Point::new(range.end.row + 1, 0);
2136            };
2137            (range.start..peek_end, end_excerpt_id)
2138        });
2139        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2140    }
2141
2142    pub fn resize_excerpt(
2143        &mut self,
2144        id: ExcerptId,
2145        range: Range<text::Anchor>,
2146        cx: &mut Context<Self>,
2147    ) {
2148        self.sync_mut(cx);
2149
2150        let mut snapshot = self.snapshot.get_mut();
2151        let locator = snapshot.excerpt_locator_for_id(id);
2152        let mut new_excerpts = SumTree::default();
2153        let mut cursor = snapshot
2154            .excerpts
2155            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2156        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2157
2158        let prefix = cursor.slice(&Some(locator), Bias::Left);
2159        new_excerpts.append(prefix, ());
2160
2161        let mut excerpt = cursor.item().unwrap().clone();
2162        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2163
2164        excerpt.range.context.start = range.start;
2165        excerpt.range.context.end = range.end;
2166        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2167
2168        excerpt.text_summary = excerpt
2169            .buffer
2170            .text_summary_for_range(excerpt.range.context.clone());
2171
2172        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2173        let old_start_offset = cursor.start().1;
2174        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2175        let edit = Edit {
2176            old: old_start_offset..old_start_offset + old_text_len,
2177            new: new_start_offset..new_start_offset + new_text_len,
2178        };
2179
2180        if let Some(last_edit) = edits.last_mut() {
2181            if last_edit.old.end == edit.old.start {
2182                last_edit.old.end = edit.old.end;
2183                last_edit.new.end = edit.new.end;
2184            } else {
2185                edits.push(edit);
2186            }
2187        } else {
2188            edits.push(edit);
2189        }
2190
2191        new_excerpts.push(excerpt, ());
2192
2193        cursor.next();
2194
2195        new_excerpts.append(cursor.suffix(), ());
2196
2197        drop(cursor);
2198        snapshot.excerpts = new_excerpts;
2199
2200        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2201        if !edits.is_empty() {
2202            self.subscriptions.publish(edits);
2203        }
2204        cx.emit(Event::Edited {
2205            edited_buffer: None,
2206        });
2207        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2208        cx.notify();
2209    }
2210
2211    pub fn expand_excerpts(
2212        &mut self,
2213        ids: impl IntoIterator<Item = ExcerptId>,
2214        line_count: u32,
2215        direction: ExpandExcerptDirection,
2216        cx: &mut Context<Self>,
2217    ) {
2218        if line_count == 0 {
2219            return;
2220        }
2221        self.sync_mut(cx);
2222        if !self.excerpts_by_path.is_empty() {
2223            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2224            return;
2225        }
2226        let mut snapshot = self.snapshot.get_mut();
2227
2228        let ids = ids.into_iter().collect::<Vec<_>>();
2229        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2230        let mut new_excerpts = SumTree::default();
2231        let mut cursor = snapshot
2232            .excerpts
2233            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2234        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2235
2236        for locator in &locators {
2237            let prefix = cursor.slice(&Some(locator), Bias::Left);
2238            new_excerpts.append(prefix, ());
2239
2240            let mut excerpt = cursor.item().unwrap().clone();
2241            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2242
2243            let up_line_count = if direction.should_expand_up() {
2244                line_count
2245            } else {
2246                0
2247            };
2248
2249            let start_row = excerpt
2250                .range
2251                .context
2252                .start
2253                .to_point(&excerpt.buffer)
2254                .row
2255                .saturating_sub(up_line_count);
2256            let start_point = Point::new(start_row, 0);
2257            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2258
2259            let down_line_count = if direction.should_expand_down() {
2260                line_count
2261            } else {
2262                0
2263            };
2264
2265            let mut end_point = excerpt.buffer.clip_point(
2266                excerpt.range.context.end.to_point(&excerpt.buffer)
2267                    + Point::new(down_line_count, 0),
2268                Bias::Left,
2269            );
2270            end_point.column = excerpt.buffer.line_len(end_point.row);
2271            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2272            excerpt.max_buffer_row = end_point.row;
2273
2274            excerpt.text_summary = excerpt
2275                .buffer
2276                .text_summary_for_range(excerpt.range.context.clone());
2277
2278            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2279            let old_start_offset = cursor.start().1;
2280            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2281            let edit = Edit {
2282                old: old_start_offset..old_start_offset + old_text_len,
2283                new: new_start_offset..new_start_offset + new_text_len,
2284            };
2285
2286            if let Some(last_edit) = edits.last_mut() {
2287                if last_edit.old.end == edit.old.start {
2288                    last_edit.old.end = edit.old.end;
2289                    last_edit.new.end = edit.new.end;
2290                } else {
2291                    edits.push(edit);
2292                }
2293            } else {
2294                edits.push(edit);
2295            }
2296
2297            new_excerpts.push(excerpt, ());
2298
2299            cursor.next();
2300        }
2301
2302        new_excerpts.append(cursor.suffix(), ());
2303
2304        drop(cursor);
2305        snapshot.excerpts = new_excerpts;
2306
2307        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2308        if !edits.is_empty() {
2309            self.subscriptions.publish(edits);
2310        }
2311        cx.emit(Event::Edited {
2312            edited_buffer: None,
2313        });
2314        cx.emit(Event::ExcerptsExpanded { ids });
2315        cx.notify();
2316    }
2317
2318    fn sync(&self, cx: &App) {
2319        let changed = self.buffer_changed_since_sync.replace(false);
2320        if !changed {
2321            return;
2322        }
2323        let edits = Self::sync_(
2324            &mut self.snapshot.borrow_mut(),
2325            &self.buffers,
2326            &self.diffs,
2327            cx,
2328        );
2329        if !edits.is_empty() {
2330            self.subscriptions.publish(edits);
2331        }
2332    }
2333
2334    fn sync_mut(&mut self, cx: &App) {
2335        let changed = self.buffer_changed_since_sync.replace(false);
2336        if !changed {
2337            return;
2338        }
2339        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2340
2341        if !edits.is_empty() {
2342            self.subscriptions.publish(edits);
2343        }
2344    }
2345
2346    fn sync_(
2347        snapshot: &mut MultiBufferSnapshot,
2348        buffers: &HashMap<BufferId, BufferState>,
2349        diffs: &HashMap<BufferId, DiffState>,
2350        cx: &App,
2351    ) -> Vec<Edit<usize>> {
2352        let MultiBufferSnapshot {
2353            excerpts,
2354            diffs: buffer_diff,
2355            diff_transforms: _,
2356            non_text_state_update_count,
2357            edit_count,
2358            is_dirty,
2359            has_deleted_file,
2360            has_conflict,
2361            singleton: _,
2362            excerpt_ids: _,
2363            replaced_excerpts: _,
2364            trailing_excerpt_update_count: _,
2365            all_diff_hunks_expanded: _,
2366            show_headers: _,
2367        } = snapshot;
2368        *is_dirty = false;
2369        *has_deleted_file = false;
2370        *has_conflict = false;
2371
2372        let mut excerpts_to_edit = Vec::new();
2373        let mut non_text_state_updated = false;
2374        let mut edited = false;
2375        for buffer_state in buffers.values() {
2376            let buffer = buffer_state.buffer.read(cx);
2377            let version = buffer.version();
2378            let non_text_state_update_count = buffer.non_text_state_update_count();
2379
2380            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2381            let buffer_non_text_state_updated =
2382                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2383            if buffer_edited || buffer_non_text_state_updated {
2384                *buffer_state.last_version.borrow_mut() = version;
2385                buffer_state
2386                    .last_non_text_state_update_count
2387                    .set(non_text_state_update_count);
2388                excerpts_to_edit.extend(
2389                    buffer_state
2390                        .excerpts
2391                        .iter()
2392                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2393                );
2394            }
2395
2396            edited |= buffer_edited;
2397            non_text_state_updated |= buffer_non_text_state_updated;
2398            *is_dirty |= buffer.is_dirty();
2399            *has_deleted_file |= buffer
2400                .file()
2401                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2402            *has_conflict |= buffer.has_conflict();
2403        }
2404        if edited {
2405            *edit_count += 1;
2406        }
2407        if non_text_state_updated {
2408            *non_text_state_update_count += 1;
2409        }
2410
2411        for (id, diff) in diffs.iter() {
2412            if buffer_diff.get(id).is_none() {
2413                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2414            }
2415        }
2416
2417        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2418
2419        let mut edits = Vec::new();
2420        let mut new_excerpts = SumTree::default();
2421        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2422
2423        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2424            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2425            let old_excerpt = cursor.item().unwrap();
2426            let buffer = buffer.read(cx);
2427            let buffer_id = buffer.remote_id();
2428
2429            let mut new_excerpt;
2430            if buffer_edited {
2431                edits.extend(
2432                    buffer
2433                        .edits_since_in_range::<usize>(
2434                            old_excerpt.buffer.version(),
2435                            old_excerpt.range.context.clone(),
2436                        )
2437                        .map(|edit| {
2438                            let excerpt_old_start = cursor.start().1;
2439                            let excerpt_new_start =
2440                                ExcerptOffset::new(new_excerpts.summary().text.len);
2441                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2442                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2443                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2444                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2445                            Edit {
2446                                old: old_start..old_end,
2447                                new: new_start..new_end,
2448                            }
2449                        }),
2450                );
2451
2452                new_excerpt = Excerpt::new(
2453                    old_excerpt.id,
2454                    locator.clone(),
2455                    buffer_id,
2456                    buffer.snapshot(),
2457                    old_excerpt.range.clone(),
2458                    old_excerpt.has_trailing_newline,
2459                );
2460            } else {
2461                new_excerpt = old_excerpt.clone();
2462                new_excerpt.buffer = buffer.snapshot();
2463            }
2464
2465            new_excerpts.push(new_excerpt, ());
2466            cursor.next();
2467        }
2468        new_excerpts.append(cursor.suffix(), ());
2469
2470        drop(cursor);
2471        *excerpts = new_excerpts;
2472        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2473    }
2474
2475    fn sync_diff_transforms(
2476        snapshot: &mut MultiBufferSnapshot,
2477        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2478        change_kind: DiffChangeKind,
2479    ) -> Vec<Edit<usize>> {
2480        if excerpt_edits.is_empty() {
2481            return vec![];
2482        }
2483
2484        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2485        let mut old_diff_transforms = snapshot
2486            .diff_transforms
2487            .cursor::<Dimensions<ExcerptOffset, usize>>(());
2488        let mut new_diff_transforms = SumTree::default();
2489        let mut old_expanded_hunks = HashSet::default();
2490        let mut output_edits = Vec::new();
2491        let mut output_delta = 0_isize;
2492        let mut at_transform_boundary = true;
2493        let mut end_of_current_insert = None;
2494
2495        let mut excerpt_edits: VecDeque<_> = excerpt_edits.into_iter().collect();
2496        while let Some(edit) = excerpt_edits.pop_front() {
2497            excerpts.seek_forward(&edit.new.start, Bias::Right);
2498            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2499                excerpts.prev();
2500            }
2501
2502            // Keep any transforms that are before the edit.
2503            if at_transform_boundary {
2504                at_transform_boundary = false;
2505                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2506                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2507                if let Some(transform) = old_diff_transforms.item()
2508                    && old_diff_transforms.end().0 == edit.old.start
2509                    && old_diff_transforms.start().0 < edit.old.start
2510                {
2511                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2512                    old_diff_transforms.next();
2513                }
2514            }
2515
2516            // Compute the start of the edit in output coordinates.
2517            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2518            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2519            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2520
2521            // -----OLD-----
2522            // - foo
2523            // + bar
2524            //
2525            // -----NEW----
2526            // - foo
2527            //   <b><AR>
2528            //
2529            //
2530            // 1.  b  a  r
2531            //    |-added-|
2532            //
2533            // 2.  b  a  r
2534            //    |-added-|
2535            //      <--e-->
2536            // 3.  b  A  R
2537            //    |-|-----|   // PROBLEM: "diff hunks intersecting `e`" is empty
2538            //      <--e-->
2539            // 4.  b  A  R    // recalculate diffs
2540            //    |-------|
2541            //
2542            //
2543            // solution 1:
2544
2545            let (changed_diff_hunks, additional_edit) = Self::recompute_diff_transforms_for_edit(
2546                &edit,
2547                &mut excerpts,
2548                &mut old_diff_transforms,
2549                &mut new_diff_transforms,
2550                &mut end_of_current_insert,
2551                &mut old_expanded_hunks,
2552                snapshot,
2553                change_kind,
2554            );
2555
2556            if let Some(mut additional_edit) = additional_edit {
2557                let mut last_overlapping_edit = None;
2558                while let Some(next_edit) = excerpt_edits.front()
2559                    && next_edit.new.overlaps(&additional_edit.new)
2560                {
2561                    last_overlapping_edit = Some(next_edit.clone());
2562                    excerpt_edits.pop_front();
2563                }
2564                if let Some(last_overlapping_edit) = last_overlapping_edit {
2565                    additional_edit.old.end = last_overlapping_edit.old.end;
2566                    if additional_edit.new.end > last_overlapping_edit.new.end {
2567                        let overshoot = additional_edit.new.end - last_overlapping_edit.new.end;
2568                        additional_edit.old.end += overshoot;
2569                    } else {
2570                        additional_edit.new.end = last_overlapping_edit.new.end;
2571                    }
2572                }
2573                excerpt_edits.push_front(additional_edit);
2574            }
2575
2576            // Compute the end of the edit in output coordinates.
2577            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2578            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2579            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2580            let edit_new_end =
2581                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2582            let output_edit = Edit {
2583                old: edit_old_start..edit_old_end,
2584                new: edit_new_start..edit_new_end,
2585            };
2586
2587            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2588            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2589            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2590                let pushing_output_edit = output_edit;
2591                output_edits.push(pushing_output_edit);
2592            }
2593
2594            // If this is the last edit that intersects the current diff transform,
2595            // then recreate the content up to the end of this transform, to prepare
2596            // for reusing additional slices of the old transforms.
2597            if excerpt_edits
2598                .front()
2599                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2600            {
2601                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2602                    && match old_diff_transforms.item() {
2603                        Some(DiffTransform::BufferContent {
2604                            inserted_hunk_info: Some(hunk),
2605                            ..
2606                        }) => excerpts.item().is_some_and(|excerpt| {
2607                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2608                        }),
2609                        _ => true,
2610                    };
2611
2612                let mut excerpt_offset = edit.new.end;
2613                if !keep_next_old_transform {
2614                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2615                    old_diff_transforms.next();
2616                }
2617
2618                old_expanded_hunks.clear();
2619                Self::push_buffer_content_transform(
2620                    snapshot,
2621                    &mut new_diff_transforms,
2622                    excerpt_offset,
2623                    end_of_current_insert,
2624                );
2625                at_transform_boundary = true;
2626            }
2627        }
2628
2629        // Keep any transforms that are after the last edit.
2630        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2631
2632        // Ensure there's always at least one buffer content transform.
2633        if new_diff_transforms.is_empty() {
2634            new_diff_transforms.push(
2635                DiffTransform::BufferContent {
2636                    summary: Default::default(),
2637                    inserted_hunk_info: None,
2638                },
2639                (),
2640            );
2641        }
2642
2643        drop(old_diff_transforms);
2644        drop(excerpts);
2645        snapshot.diff_transforms = new_diff_transforms;
2646        snapshot.edit_count += 1;
2647
2648        #[cfg(any(test, feature = "test-support"))]
2649        snapshot.check_invariants();
2650        output_edits
2651    }
2652
2653    fn recompute_diff_transforms_for_edit(
2654        edit: &Edit<TypedOffset<Excerpt>>,
2655        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2656        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
2657        new_diff_transforms: &mut SumTree<DiffTransform>,
2658        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2659        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2660        snapshot: &MultiBufferSnapshot,
2661        change_kind: DiffChangeKind,
2662    ) -> (bool, Option<Edit<TypedOffset<Excerpt>>>) {
2663        log::trace!(
2664            "recomputing diff transform for edit {:?} => {:?}",
2665            edit.old.start.value..edit.old.end.value,
2666            edit.new.start.value..edit.new.end.value
2667        );
2668
2669        // Record which hunks were previously expanded.
2670        while let Some(item) = old_diff_transforms.item() {
2671            if let Some(hunk_info) = item.hunk_info() {
2672                log::trace!(
2673                    "previously expanded hunk at {}",
2674                    old_diff_transforms.start().0
2675                );
2676                old_expanded_hunks.insert(hunk_info);
2677            }
2678            if old_diff_transforms.end().0 > edit.old.end {
2679                break;
2680            }
2681            old_diff_transforms.next();
2682        }
2683
2684        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2685        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2686        if old_expanded_hunks.is_empty()
2687            && change_kind == DiffChangeKind::BufferEdited
2688            && !all_diff_hunks_expanded
2689        {
2690            return (false, None);
2691        }
2692
2693        let mut override_query_range_start = Some(new_diff_transforms.summary().excerpt_len());
2694
2695        // Visit each excerpt that intersects the edit.
2696        let mut did_expand_hunks = false;
2697        let mut additional_edit = None;
2698        while let Some(excerpt) = excerpts.item() {
2699            // Recompute the expanded hunks in the portion of the excerpt that
2700            // intersects the edit.
2701            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2702                let buffer = &excerpt.buffer;
2703                let excerpt_start = *excerpts.start();
2704                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2705                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2706                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2707                let edit_buffer_start =
2708                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2709                let edit_buffer_end =
2710                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2711                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2712
2713                let query_range = if let Some(query_range_start) = override_query_range_start.take()
2714                {
2715                    let query_range_buffer_start = query_range_start
2716                        .max(excerpt_start)
2717                        .sub(excerpt_start)
2718                        .value
2719                        + excerpt_buffer_start;
2720                    buffer.anchor_before(query_range_buffer_start)
2721                        ..buffer.anchor_after(edit_buffer_end)
2722                } else {
2723                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end)
2724                };
2725
2726                for hunk in diff.valid_and_invalid_hunks_intersecting_range(query_range, buffer) {
2727                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2728                        continue;
2729                    }
2730
2731                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2732                    if hunk_buffer_range.start < excerpt_buffer_start {
2733                        log::trace!("skipping hunk that starts before excerpt");
2734                        continue;
2735                    }
2736
2737                    let hunk_info = DiffTransformHunkInfo {
2738                        excerpt_id: excerpt.id,
2739                        hunk_start_anchor: hunk.buffer_range.start,
2740                        hunk_secondary_status: hunk.secondary_status,
2741                    };
2742
2743                    let hunk_excerpt_start = excerpt_start
2744                        + ExcerptOffset::new(
2745                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2746                        );
2747                    let hunk_excerpt_end = excerpt_end.min(
2748                        excerpt_start
2749                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2750                    );
2751
2752                    if !hunk.buffer_range.start.is_valid(buffer) {
2753                        if old_expanded_hunks.contains(&hunk_info)
2754                            && hunk_excerpt_end > edit.new.end
2755                        {
2756                            let overshoot = hunk_excerpt_end - edit.new.end;
2757                            additional_edit = Some(Edit {
2758                                old: edit.old.end..edit.old.end + overshoot,
2759                                new: edit.new.end..hunk_excerpt_end,
2760                            });
2761                        }
2762                        continue;
2763                    }
2764
2765                    Self::push_buffer_content_transform(
2766                        snapshot,
2767                        new_diff_transforms,
2768                        hunk_excerpt_start,
2769                        *end_of_current_insert,
2770                    );
2771
2772                    // For every existing hunk, determine if it was previously expanded
2773                    // and if it should currently be expanded.
2774                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2775                    let should_expand_hunk = match &change_kind {
2776                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2777                            was_previously_expanded || all_diff_hunks_expanded
2778                        }
2779                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2780                            let intersects = hunk_buffer_range.is_empty()
2781                                || hunk_buffer_range.end > edit_buffer_start;
2782                            if *expand {
2783                                intersects || was_previously_expanded || all_diff_hunks_expanded
2784                            } else {
2785                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
2786                            }
2787                        }
2788                        _ => was_previously_expanded || all_diff_hunks_expanded,
2789                    };
2790
2791                    if should_expand_hunk {
2792                        did_expand_hunks = true;
2793                        log::trace!(
2794                            "expanding hunk {:?}, excerpt:{:?}",
2795                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2796                            excerpt.id
2797                        );
2798
2799                        if !hunk.diff_base_byte_range.is_empty()
2800                            && hunk_buffer_range.start >= edit_buffer_start
2801                            && hunk_buffer_range.start <= excerpt_buffer_end
2802                        {
2803                            let base_text = diff.base_text();
2804                            let mut text_cursor =
2805                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2806                            let mut base_text_summary =
2807                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2808
2809                            let mut has_trailing_newline = false;
2810                            if base_text_summary.last_line_chars > 0 {
2811                                base_text_summary += TextSummary::newline();
2812                                has_trailing_newline = true;
2813                            }
2814
2815                            new_diff_transforms.push(
2816                                DiffTransform::DeletedHunk {
2817                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2818                                    summary: base_text_summary,
2819                                    buffer_id: excerpt.buffer_id,
2820                                    hunk_info,
2821                                    has_trailing_newline,
2822                                },
2823                                (),
2824                            );
2825                        }
2826
2827                        if !hunk_buffer_range.is_empty() {
2828                            *end_of_current_insert =
2829                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2830                        }
2831                    }
2832                }
2833            }
2834
2835            if excerpts.end() <= edit.new.end {
2836                excerpts.next();
2837            } else {
2838                break;
2839            }
2840        }
2841
2842        (
2843            did_expand_hunks || !old_expanded_hunks.is_empty(),
2844            additional_edit,
2845        )
2846    }
2847
2848    fn append_diff_transforms(
2849        new_transforms: &mut SumTree<DiffTransform>,
2850        subtree: SumTree<DiffTransform>,
2851    ) {
2852        if let Some(DiffTransform::BufferContent {
2853            inserted_hunk_info,
2854            summary,
2855        }) = subtree.first()
2856            && Self::extend_last_buffer_content_transform(
2857                new_transforms,
2858                *inserted_hunk_info,
2859                *summary,
2860            )
2861        {
2862            let mut cursor = subtree.cursor::<()>(());
2863            cursor.next();
2864            cursor.next();
2865            new_transforms.append(cursor.suffix(), ());
2866            return;
2867        }
2868        new_transforms.append(subtree, ());
2869    }
2870
2871    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
2872        if let DiffTransform::BufferContent {
2873            inserted_hunk_info: inserted_hunk_anchor,
2874            summary,
2875        } = transform
2876            && Self::extend_last_buffer_content_transform(
2877                new_transforms,
2878                inserted_hunk_anchor,
2879                summary,
2880            )
2881        {
2882            return;
2883        }
2884        new_transforms.push(transform, ());
2885    }
2886
2887    fn push_buffer_content_transform(
2888        old_snapshot: &MultiBufferSnapshot,
2889        new_transforms: &mut SumTree<DiffTransform>,
2890        end_offset: ExcerptOffset,
2891        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2892    ) {
2893        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
2894            (end_offset.min(insertion_end_offset), Some(hunk_info))
2895        });
2896        let unchanged_region = [(end_offset, None)];
2897
2898        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
2899        {
2900            let start_offset = new_transforms.summary().excerpt_len();
2901            if end_offset <= start_offset {
2902                continue;
2903            }
2904            let summary_to_add = old_snapshot
2905                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2906
2907            if !Self::extend_last_buffer_content_transform(
2908                new_transforms,
2909                inserted_hunk_info,
2910                summary_to_add,
2911            ) {
2912                new_transforms.push(
2913                    DiffTransform::BufferContent {
2914                        summary: summary_to_add,
2915                        inserted_hunk_info: inserted_hunk_info,
2916                    },
2917                    (),
2918                )
2919            }
2920        }
2921    }
2922
2923    fn extend_last_buffer_content_transform(
2924        new_transforms: &mut SumTree<DiffTransform>,
2925        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
2926        summary_to_add: TextSummary,
2927    ) -> bool {
2928        let mut did_extend = false;
2929        new_transforms.update_last(
2930            |last_transform| {
2931                if let DiffTransform::BufferContent {
2932                    summary,
2933                    inserted_hunk_info: inserted_hunk_anchor,
2934                } = last_transform
2935                    && *inserted_hunk_anchor == new_inserted_hunk_info
2936                {
2937                    *summary += summary_to_add;
2938                    did_extend = true;
2939                }
2940            },
2941            (),
2942        );
2943        did_extend
2944    }
2945}
2946
2947fn build_excerpt_ranges(
2948    ranges: impl IntoIterator<Item = Range<Point>>,
2949    context_line_count: u32,
2950    buffer_snapshot: &BufferSnapshot,
2951) -> Vec<ExcerptRange<Point>> {
2952    ranges
2953        .into_iter()
2954        .map(|range| {
2955            let start_row = range.start.row.saturating_sub(context_line_count);
2956            let start = Point::new(start_row, 0);
2957            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
2958            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
2959            ExcerptRange {
2960                context: start..end,
2961                primary: range,
2962            }
2963        })
2964        .collect()
2965}
2966
2967#[cfg(any(test, feature = "test-support"))]
2968impl MultiBuffer {
2969    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2970        let buffer = cx.new(|cx| Buffer::local(text, cx));
2971        cx.new(|cx| Self::singleton(buffer, cx))
2972    }
2973
2974    pub fn build_multi<const COUNT: usize>(
2975        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2976        cx: &mut gpui::App,
2977    ) -> Entity<Self> {
2978        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2979        for (text, ranges) in excerpts {
2980            let buffer = cx.new(|cx| Buffer::local(text, cx));
2981            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
2982            multi.update(cx, |multi, cx| {
2983                multi.push_excerpts(buffer, excerpt_ranges, cx)
2984            });
2985        }
2986
2987        multi
2988    }
2989
2990    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
2991        cx.new(|cx| Self::singleton(buffer, cx))
2992    }
2993
2994    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
2995        cx.new(|cx| {
2996            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
2997            let mutation_count = rng.random_range(1..=5);
2998            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
2999            multibuffer
3000        })
3001    }
3002
3003    pub fn randomly_edit(
3004        &mut self,
3005        rng: &mut impl rand::Rng,
3006        edit_count: usize,
3007        cx: &mut Context<Self>,
3008    ) {
3009        use util::RandomCharIter;
3010
3011        let snapshot = self.read(cx);
3012        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3013        let mut last_end = None;
3014        for _ in 0..edit_count {
3015            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3016                break;
3017            }
3018
3019            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3020            let end =
3021                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3022            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3023            last_end = Some(end);
3024
3025            let mut range = start..end;
3026            if rng.random_bool(0.2) {
3027                mem::swap(&mut range.start, &mut range.end);
3028            }
3029
3030            let new_text_len = rng.random_range(0..10);
3031            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3032
3033            edits.push((range, new_text.into()));
3034        }
3035        log::info!("mutating multi-buffer with {:?}", edits);
3036        drop(snapshot);
3037
3038        self.edit(edits, None, cx);
3039    }
3040
3041    pub fn randomly_edit_excerpts(
3042        &mut self,
3043        rng: &mut impl rand::Rng,
3044        mutation_count: usize,
3045        cx: &mut Context<Self>,
3046    ) {
3047        use rand::prelude::*;
3048        use std::env;
3049        use util::RandomCharIter;
3050
3051        let max_excerpts = env::var("MAX_EXCERPTS")
3052            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3053            .unwrap_or(5);
3054
3055        let mut buffers = Vec::new();
3056        for _ in 0..mutation_count {
3057            if rng.random_bool(0.05) {
3058                log::info!("Clearing multi-buffer");
3059                self.clear(cx);
3060                continue;
3061            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3062                let ids = self.excerpt_ids();
3063                let mut excerpts = HashSet::default();
3064                for _ in 0..rng.random_range(0..ids.len()) {
3065                    excerpts.extend(ids.choose(rng).copied());
3066                }
3067
3068                let line_count = rng.random_range(0..5);
3069
3070                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3071
3072                self.expand_excerpts(
3073                    excerpts.iter().cloned(),
3074                    line_count,
3075                    ExpandExcerptDirection::UpAndDown,
3076                    cx,
3077                );
3078                continue;
3079            }
3080
3081            let excerpt_ids = self.excerpt_ids();
3082            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3083                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3084                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3085                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3086                    let buffer = buffers.last().unwrap().read(cx);
3087                    log::info!(
3088                        "Creating new buffer {} with text: {:?}",
3089                        buffer.remote_id(),
3090                        buffer.text()
3091                    );
3092                    buffers.last().unwrap().clone()
3093                } else {
3094                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3095                };
3096
3097                let buffer = buffer_handle.read(cx);
3098                let buffer_text = buffer.text();
3099                let ranges = (0..rng.random_range(0..5))
3100                    .map(|_| {
3101                        let end_ix =
3102                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3103                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3104                        ExcerptRange::new(start_ix..end_ix)
3105                    })
3106                    .collect::<Vec<_>>();
3107                log::info!(
3108                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3109                    buffer_handle.read(cx).remote_id(),
3110                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3111                    ranges
3112                        .iter()
3113                        .map(|r| &buffer_text[r.context.clone()])
3114                        .collect::<Vec<_>>()
3115                );
3116
3117                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3118                log::info!("Inserted with ids: {:?}", excerpt_id);
3119            } else {
3120                let remove_count = rng.random_range(1..=excerpt_ids.len());
3121                let mut excerpts_to_remove = excerpt_ids
3122                    .choose_multiple(rng, remove_count)
3123                    .cloned()
3124                    .collect::<Vec<_>>();
3125                let snapshot = self.snapshot.borrow();
3126                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3127                drop(snapshot);
3128                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3129                self.remove_excerpts(excerpts_to_remove, cx);
3130            }
3131        }
3132    }
3133
3134    pub fn randomly_mutate(
3135        &mut self,
3136        rng: &mut impl rand::Rng,
3137        mutation_count: usize,
3138        cx: &mut Context<Self>,
3139    ) {
3140        use rand::prelude::*;
3141
3142        if rng.random_bool(0.7) || self.singleton {
3143            let buffer = self
3144                .buffers
3145                .values()
3146                .choose(rng)
3147                .map(|state| state.buffer.clone());
3148
3149            if let Some(buffer) = buffer {
3150                buffer.update(cx, |buffer, cx| {
3151                    if rng.random() {
3152                        buffer.randomly_edit(rng, mutation_count, cx);
3153                    } else {
3154                        buffer.randomly_undo_redo(rng, cx);
3155                    }
3156                });
3157            } else {
3158                self.randomly_edit(rng, mutation_count, cx);
3159            }
3160        } else {
3161            self.randomly_edit_excerpts(rng, mutation_count, cx);
3162        }
3163
3164        self.check_invariants(cx);
3165    }
3166
3167    fn check_invariants(&self, cx: &App) {
3168        self.read(cx).check_invariants();
3169    }
3170}
3171
3172impl EventEmitter<Event> for MultiBuffer {}
3173
3174impl MultiBufferSnapshot {
3175    pub fn text(&self) -> String {
3176        self.chunks(0..self.len(), false)
3177            .map(|chunk| chunk.text)
3178            .collect()
3179    }
3180
3181    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3182        self.reversed_chunks_in_range(0..position.to_offset(self))
3183            .flat_map(|c| c.chars().rev())
3184    }
3185
3186    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3187        let mut cursor = self.cursor::<usize>();
3188        cursor.seek(&range.end);
3189        let current_chunks = cursor.region().as_ref().map(|region| {
3190            let start_overshoot = range.start.saturating_sub(region.range.start);
3191            let end_overshoot = range.end - region.range.start;
3192            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3193            let start = region.buffer_range.start + start_overshoot;
3194            region.buffer.reversed_chunks_in_range(start..end)
3195        });
3196        ReversedMultiBufferChunks {
3197            cursor,
3198            current_chunks,
3199            start: range.start,
3200            offset: range.end,
3201        }
3202    }
3203
3204    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3205        let offset = position.to_offset(self);
3206        self.text_for_range(offset..self.len())
3207            .flat_map(|chunk| chunk.chars())
3208    }
3209
3210    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3211        self.chunks(range, false).map(|chunk| chunk.text)
3212    }
3213
3214    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3215        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3216            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3217    }
3218
3219    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3220    where
3221        T: ToOffset,
3222    {
3223        let position = position.to_offset(self);
3224        position == self.clip_offset(position, Bias::Left)
3225            && self
3226                .bytes_in_range(position..self.len())
3227                .flatten()
3228                .copied()
3229                .take(needle.len())
3230                .eq(needle.bytes())
3231    }
3232
3233    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3234        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3235    }
3236
3237    pub fn diff_hunks_in_range<T: ToPoint>(
3238        &self,
3239        range: Range<T>,
3240    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3241        let query_range = range.start.to_point(self)..range.end.to_point(self);
3242        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3243            let diff = self.diffs.get(&buffer.remote_id())?;
3244            let buffer_start = buffer.anchor_before(buffer_range.start);
3245            let buffer_end = buffer.anchor_after(buffer_range.end);
3246            Some(
3247                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3248                    .filter_map(|hunk| {
3249                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3250                            return None;
3251                        }
3252                        Some((hunk.range.clone(), hunk))
3253                    }),
3254            )
3255        })
3256        .filter_map(move |(range, hunk, excerpt)| {
3257            if hunk.range.start < excerpt.range.context.start.to_point(&excerpt.buffer) {
3258                return None;
3259            }
3260            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3261            {
3262                return None;
3263            }
3264            let end_row = if range.end.column == 0 {
3265                range.end.row
3266            } else {
3267                range.end.row + 1
3268            };
3269            Some(MultiBufferDiffHunk {
3270                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3271                buffer_id: excerpt.buffer_id,
3272                excerpt_id: excerpt.id,
3273                buffer_range: hunk.buffer_range.clone(),
3274                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3275                secondary_status: hunk.secondary_status,
3276            })
3277        })
3278    }
3279
3280    pub fn excerpt_ids_for_range<T: ToOffset>(
3281        &self,
3282        range: Range<T>,
3283    ) -> impl Iterator<Item = ExcerptId> + '_ {
3284        let range = range.start.to_offset(self)..range.end.to_offset(self);
3285        let mut cursor = self.cursor::<usize>();
3286        cursor.seek(&range.start);
3287        std::iter::from_fn(move || {
3288            let region = cursor.region()?;
3289            if region.range.start >= range.end {
3290                return None;
3291            }
3292            cursor.next_excerpt();
3293            Some(region.excerpt.id)
3294        })
3295    }
3296
3297    pub fn buffer_ids_for_range<T: ToOffset>(
3298        &self,
3299        range: Range<T>,
3300    ) -> impl Iterator<Item = BufferId> + '_ {
3301        let range = range.start.to_offset(self)..range.end.to_offset(self);
3302        let mut cursor = self.cursor::<usize>();
3303        cursor.seek(&range.start);
3304        std::iter::from_fn(move || {
3305            let region = cursor.region()?;
3306            if region.range.start > range.end
3307                || region.range.start == range.end && region.range.start > range.start
3308            {
3309                return None;
3310            }
3311            cursor.next_excerpt();
3312            Some(region.excerpt.buffer_id)
3313        })
3314    }
3315
3316    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3317        &self,
3318        ranges: impl Iterator<Item = Range<T>>,
3319    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3320        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3321    }
3322
3323    pub fn range_to_buffer_ranges<T: ToOffset>(
3324        &self,
3325        range: Range<T>,
3326    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3327        let start = range.start.to_offset(self);
3328        let end = range.end.to_offset(self);
3329
3330        let mut cursor = self.cursor::<usize>();
3331        cursor.seek(&start);
3332
3333        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3334        while let Some(region) = cursor.region() {
3335            if region.range.start > end {
3336                break;
3337            }
3338            if region.is_main_buffer {
3339                let start_overshoot = start.saturating_sub(region.range.start);
3340                let end_overshoot = end.saturating_sub(region.range.start);
3341                let start = region
3342                    .buffer_range
3343                    .end
3344                    .min(region.buffer_range.start + start_overshoot);
3345                let end = region
3346                    .buffer_range
3347                    .end
3348                    .min(region.buffer_range.start + end_overshoot);
3349                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3350                    *excerpt_id == region.excerpt.id && prev_range.end == start
3351                }) {
3352                    prev.1.end = end;
3353                } else {
3354                    result.push((region.buffer, start..end, region.excerpt.id));
3355                }
3356            }
3357            cursor.next();
3358        }
3359        result
3360    }
3361
3362    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3363        &self,
3364        range: Range<T>,
3365    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3366        let start = range.start.to_offset(self);
3367        let end = range.end.to_offset(self);
3368
3369        let mut cursor = self.cursor::<usize>();
3370        cursor.seek(&start);
3371
3372        std::iter::from_fn(move || {
3373            let region = cursor.region()?;
3374            if region.range.start > end {
3375                return None;
3376            }
3377            let start_overshoot = start.saturating_sub(region.range.start);
3378            let end_overshoot = end.saturating_sub(region.range.start);
3379            let start = region
3380                .buffer_range
3381                .end
3382                .min(region.buffer_range.start + start_overshoot);
3383            let end = region
3384                .buffer_range
3385                .end
3386                .min(region.buffer_range.start + end_overshoot);
3387
3388            let region_excerpt_id = region.excerpt.id;
3389            let deleted_hunk_anchor = if region.is_main_buffer {
3390                None
3391            } else {
3392                Some(self.anchor_before(region.range.start))
3393            };
3394            let result = (
3395                region.buffer,
3396                start..end,
3397                region_excerpt_id,
3398                deleted_hunk_anchor,
3399            );
3400            cursor.next();
3401            Some(result)
3402        })
3403    }
3404
3405    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3406    /// coordinates.
3407    ///
3408    /// The given callback will be called for every excerpt intersecting the given range. It will
3409    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3410    /// The callback should return an iterator of metadata items from that buffer, each paired
3411    /// with a buffer range.
3412    ///
3413    /// The returned iterator yields each of these metadata items, paired with its range in
3414    /// multi-buffer coordinates.
3415    fn lift_buffer_metadata<'a, D, M, I>(
3416        &'a self,
3417        query_range: Range<D>,
3418        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3419    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3420    where
3421        I: Iterator<Item = (Range<D>, M)> + 'a,
3422        D: TextDimension + Ord + Sub<D, Output = D>,
3423    {
3424        let max_position = D::from_text_summary(&self.text_summary());
3425        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3426        let mut cursor = self.cursor::<D>();
3427
3428        // Find the excerpt and buffer offset where the given range ends.
3429        cursor.seek(&query_range.end);
3430        let mut range_end = None;
3431        while let Some(region) = cursor.region() {
3432            if region.is_main_buffer {
3433                let mut buffer_end = region.buffer_range.start;
3434                let overshoot = if query_range.end > region.range.start {
3435                    query_range.end - region.range.start
3436                } else {
3437                    D::default()
3438                };
3439                buffer_end.add_assign(&overshoot);
3440                range_end = Some((region.excerpt.id, buffer_end));
3441                break;
3442            }
3443            cursor.next();
3444        }
3445
3446        cursor.seek(&query_range.start);
3447
3448        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3449            && region.range.start > D::zero(())
3450        {
3451            cursor.prev()
3452        }
3453
3454        iter::from_fn(move || {
3455            loop {
3456                let excerpt = cursor.excerpt()?;
3457
3458                // If we have already retrieved metadata for this excerpt, continue to use it.
3459                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3460                    .as_mut()
3461                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3462                {
3463                    Some(metadata)
3464                }
3465                // Otherwise, compute the intersection of the input range with the excerpt's range,
3466                // and retrieve the metadata for the resulting range.
3467                else {
3468                    let region = cursor.region()?;
3469                    let mut buffer_start;
3470                    if region.is_main_buffer {
3471                        buffer_start = region.buffer_range.start;
3472                        if query_range.start > region.range.start {
3473                            let overshoot = query_range.start - region.range.start;
3474                            buffer_start.add_assign(&overshoot);
3475                        }
3476                        buffer_start = buffer_start.min(region.buffer_range.end);
3477                    } else {
3478                        buffer_start = cursor.main_buffer_position()?;
3479                    };
3480                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3481                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3482                        && excerpt.id == end_excerpt_id
3483                    {
3484                        buffer_end = buffer_end.min(end_buffer_offset);
3485                    }
3486
3487                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3488                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3489                    })
3490                };
3491
3492                // Visit each metadata item.
3493                if let Some((metadata_buffer_range, metadata)) =
3494                    metadata_iter.and_then(Iterator::next)
3495                {
3496                    // Find the multibuffer regions that contain the start and end of
3497                    // the metadata item's range.
3498                    if metadata_buffer_range.start > D::default() {
3499                        while let Some(region) = cursor.region() {
3500                            if region.is_main_buffer
3501                                && (region.buffer_range.end >= metadata_buffer_range.start
3502                                    || cursor.is_at_end_of_excerpt())
3503                            {
3504                                break;
3505                            }
3506                            cursor.next();
3507                        }
3508                    }
3509                    let start_region = cursor.region()?;
3510                    while let Some(region) = cursor.region() {
3511                        if region.is_main_buffer
3512                            && (region.buffer_range.end > metadata_buffer_range.end
3513                                || (region.buffer_range.end == metadata_buffer_range.end
3514                                    && region.diff_hunk_status.is_some())
3515                                || cursor.is_at_end_of_excerpt())
3516                        {
3517                            break;
3518                        }
3519                        cursor.next();
3520                    }
3521                    let end_region = cursor.region();
3522
3523                    // Convert the metadata item's range into multibuffer coordinates.
3524                    let mut start_position = start_region.range.start;
3525                    let region_buffer_start = start_region.buffer_range.start;
3526                    if start_region.is_main_buffer
3527                        && metadata_buffer_range.start > region_buffer_start
3528                    {
3529                        start_position
3530                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
3531                        start_position = start_position.min(start_region.range.end);
3532                    }
3533
3534                    let mut end_position = max_position;
3535                    if let Some(end_region) = &end_region {
3536                        end_position = end_region.range.start;
3537                        debug_assert!(end_region.is_main_buffer);
3538                        let region_buffer_start = end_region.buffer_range.start;
3539                        if metadata_buffer_range.end > region_buffer_start {
3540                            end_position
3541                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
3542                        }
3543                        end_position = end_position.min(end_region.range.end);
3544                    }
3545
3546                    if start_position <= query_range.end && end_position >= query_range.start {
3547                        return Some((start_position..end_position, metadata, excerpt));
3548                    }
3549                }
3550                // When there are no more metadata items for this excerpt, move to the next excerpt.
3551                else {
3552                    current_excerpt_metadata.take();
3553                    if let Some((end_excerpt_id, _)) = range_end
3554                        && excerpt.id == end_excerpt_id
3555                    {
3556                        return None;
3557                    }
3558                    cursor.next_excerpt();
3559                }
3560            }
3561        })
3562    }
3563
3564    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3565        let offset = position.to_offset(self);
3566
3567        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3568        cursor.seek(&DimensionPair {
3569            key: offset,
3570            value: None,
3571        });
3572        cursor.seek_to_start_of_current_excerpt();
3573        let excerpt = cursor.excerpt()?;
3574
3575        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3576        let current_position = self
3577            .anchor_before(offset)
3578            .text_anchor
3579            .to_offset(&excerpt.buffer);
3580        let excerpt_end = excerpt
3581            .buffer
3582            .anchor_before(excerpt_end.min(current_position));
3583
3584        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3585            for hunk in diff.hunks_intersecting_range_rev(
3586                excerpt.range.context.start..excerpt_end,
3587                &excerpt.buffer,
3588            ) {
3589                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3590                if hunk_end >= current_position {
3591                    continue;
3592                }
3593                let start =
3594                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3595                        .to_point(self);
3596                return Some(MultiBufferRow(start.row));
3597            }
3598        }
3599
3600        loop {
3601            cursor.prev_excerpt();
3602            let excerpt = cursor.excerpt()?;
3603
3604            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3605                continue;
3606            };
3607            let mut hunks =
3608                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3609            let Some(hunk) = hunks.next() else {
3610                continue;
3611            };
3612            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3613                .to_point(self);
3614            return Some(MultiBufferRow(start.row));
3615        }
3616    }
3617
3618    pub fn has_diff_hunks(&self) -> bool {
3619        self.diffs.values().any(|diff| !diff.is_empty())
3620    }
3621
3622    pub fn is_inside_word<T: ToOffset>(
3623        &self,
3624        position: T,
3625        scope_context: Option<CharScopeContext>,
3626    ) -> bool {
3627        let position = position.to_offset(self);
3628        let classifier = self
3629            .char_classifier_at(position)
3630            .scope_context(scope_context);
3631        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3632        let prev_char_kind = self
3633            .reversed_chars_at(position)
3634            .next()
3635            .map(|c| classifier.kind(c));
3636        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
3637    }
3638
3639    pub fn surrounding_word<T: ToOffset>(
3640        &self,
3641        start: T,
3642        scope_context: Option<CharScopeContext>,
3643    ) -> (Range<usize>, Option<CharKind>) {
3644        let mut start = start.to_offset(self);
3645        let mut end = start;
3646        let mut next_chars = self.chars_at(start).peekable();
3647        let mut prev_chars = self.reversed_chars_at(start).peekable();
3648
3649        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3650
3651        let word_kind = cmp::max(
3652            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3653            next_chars.peek().copied().map(|c| classifier.kind(c)),
3654        );
3655
3656        for ch in prev_chars {
3657            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3658                start -= ch.len_utf8();
3659            } else {
3660                break;
3661            }
3662        }
3663
3664        for ch in next_chars {
3665            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3666                end += ch.len_utf8();
3667            } else {
3668                break;
3669            }
3670        }
3671
3672        (start..end, word_kind)
3673    }
3674
3675    pub fn char_kind_before<T: ToOffset>(
3676        &self,
3677        start: T,
3678        scope_context: Option<CharScopeContext>,
3679    ) -> Option<CharKind> {
3680        let start = start.to_offset(self);
3681        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3682        self.reversed_chars_at(start)
3683            .next()
3684            .map(|ch| classifier.kind(ch))
3685    }
3686
3687    pub fn is_singleton(&self) -> bool {
3688        self.singleton
3689    }
3690
3691    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3692        if self.singleton {
3693            self.excerpts
3694                .iter()
3695                .next()
3696                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3697        } else {
3698            None
3699        }
3700    }
3701
3702    pub fn len(&self) -> usize {
3703        self.diff_transforms.summary().output.len
3704    }
3705
3706    pub fn is_empty(&self) -> bool {
3707        self.excerpts.summary().text.len == 0
3708    }
3709
3710    pub fn widest_line_number(&self) -> u32 {
3711        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
3712        self.excerpts.summary().widest_line_number + 1
3713    }
3714
3715    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
3716        let range = range.start.to_offset(self)..range.end.to_offset(self);
3717        let mut excerpts = self.cursor::<usize>();
3718        excerpts.seek(&range.start);
3719
3720        let mut chunk;
3721        let mut has_trailing_newline;
3722        let excerpt_bytes;
3723        if let Some(region) = excerpts.region() {
3724            let mut bytes = region.buffer.bytes_in_range(
3725                region.buffer_range.start + range.start - region.range.start
3726                    ..(region.buffer_range.start + range.end - region.range.start)
3727                        .min(region.buffer_range.end),
3728            );
3729            chunk = bytes.next().unwrap_or(&[][..]);
3730            excerpt_bytes = Some(bytes);
3731            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3732            if chunk.is_empty() && has_trailing_newline {
3733                chunk = b"\n";
3734                has_trailing_newline = false;
3735            }
3736        } else {
3737            chunk = &[][..];
3738            excerpt_bytes = None;
3739            has_trailing_newline = false;
3740        };
3741
3742        MultiBufferBytes {
3743            range,
3744            cursor: excerpts,
3745            excerpt_bytes,
3746            has_trailing_newline,
3747            chunk,
3748        }
3749    }
3750
3751    pub fn reversed_bytes_in_range<T: ToOffset>(
3752        &self,
3753        range: Range<T>,
3754    ) -> ReversedMultiBufferBytes<'_> {
3755        let range = range.start.to_offset(self)..range.end.to_offset(self);
3756        let mut chunks = self.reversed_chunks_in_range(range.clone());
3757        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3758        ReversedMultiBufferBytes {
3759            range,
3760            chunks,
3761            chunk,
3762        }
3763    }
3764
3765    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
3766        let mut cursor = self.cursor::<Point>();
3767        cursor.seek(&Point::new(start_row.0, 0));
3768        let mut result = MultiBufferRows {
3769            point: Point::new(0, 0),
3770            is_empty: self.excerpts.is_empty(),
3771            is_singleton: self.is_singleton(),
3772            cursor,
3773        };
3774        result.seek(start_row);
3775        result
3776    }
3777
3778    pub fn chunks<T: ToOffset>(
3779        &self,
3780        range: Range<T>,
3781        language_aware: bool,
3782    ) -> MultiBufferChunks<'_> {
3783        let mut chunks = MultiBufferChunks {
3784            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3785            range: 0..0,
3786            excerpts: self.excerpts.cursor(()),
3787            diff_transforms: self.diff_transforms.cursor(()),
3788            diffs: &self.diffs,
3789            diff_base_chunks: None,
3790            excerpt_chunks: None,
3791            buffer_chunk: None,
3792            language_aware,
3793        };
3794        let range = range.start.to_offset(self)..range.end.to_offset(self);
3795        chunks.seek(range);
3796        chunks
3797    }
3798
3799    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3800        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3801    }
3802
3803    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3804        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3805    }
3806
3807    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3808        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3809    }
3810
3811    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3812        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3813            buffer.clip_point_utf16(Unclipped(point), bias)
3814        })
3815    }
3816
3817    pub fn offset_to_point(&self, offset: usize) -> Point {
3818        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3819    }
3820
3821    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3822        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3823    }
3824
3825    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3826        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3827    }
3828
3829    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
3830        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
3831    }
3832
3833    pub fn point_to_offset(&self, point: Point) -> usize {
3834        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3835    }
3836
3837    pub fn point_to_offset_utf16(&self, point: Point) -> OffsetUtf16 {
3838        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
3839    }
3840
3841    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3842        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3843    }
3844
3845    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3846        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3847    }
3848
3849    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3850        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3851    }
3852
3853    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> OffsetUtf16 {
3854        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
3855    }
3856
3857    fn clip_dimension<D>(
3858        &self,
3859        position: D,
3860        bias: Bias,
3861        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3862    ) -> D
3863    where
3864        D: TextDimension + Ord + Sub<D, Output = D>,
3865    {
3866        let mut cursor = self.cursor();
3867        cursor.seek(&position);
3868        if let Some(region) = cursor.region() {
3869            if position >= region.range.end {
3870                return region.range.end;
3871            }
3872            let overshoot = position - region.range.start;
3873            let mut buffer_position = region.buffer_range.start;
3874            buffer_position.add_assign(&overshoot);
3875            let clipped_buffer_position =
3876                clip_buffer_position(region.buffer, buffer_position, bias);
3877            let mut position = region.range.start;
3878            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3879            position
3880        } else {
3881            D::from_text_summary(&self.text_summary())
3882        }
3883    }
3884
3885    fn convert_dimension<D1, D2>(
3886        &self,
3887        key: D1,
3888        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3889    ) -> D2
3890    where
3891        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3892        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3893    {
3894        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3895        cursor.seek(&DimensionPair { key, value: None });
3896        if let Some(region) = cursor.region() {
3897            if key >= region.range.end.key {
3898                return region.range.end.value.unwrap();
3899            }
3900            let start_key = region.range.start.key;
3901            let start_value = region.range.start.value.unwrap();
3902            let buffer_start_key = region.buffer_range.start.key;
3903            let buffer_start_value = region.buffer_range.start.value.unwrap();
3904            let mut buffer_key = buffer_start_key;
3905            buffer_key.add_assign(&(key - start_key));
3906            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
3907            let mut result = start_value;
3908            result.add_assign(&(buffer_value - buffer_start_value));
3909            result
3910        } else {
3911            D2::from_text_summary(&self.text_summary())
3912        }
3913    }
3914
3915    pub fn point_to_buffer_offset<T: ToOffset>(
3916        &self,
3917        point: T,
3918    ) -> Option<(&BufferSnapshot, usize)> {
3919        let offset = point.to_offset(self);
3920        let mut cursor = self.cursor::<usize>();
3921        cursor.seek(&offset);
3922        let region = cursor.region()?;
3923        let overshoot = offset - region.range.start;
3924        let buffer_offset = region.buffer_range.start + overshoot;
3925        if buffer_offset == region.buffer.len() + 1
3926            && region.has_trailing_newline
3927            && !region.is_main_buffer
3928        {
3929            let main_buffer_position = cursor.main_buffer_position()?;
3930            let buffer_snapshot = &cursor.excerpt()?.buffer;
3931            // remove this assert once we figure out the cause of the panics for #40453
3932            buffer_snapshot
3933                .text
3934                .as_rope()
3935                .assert_char_boundary(main_buffer_position);
3936            return Some((buffer_snapshot, main_buffer_position));
3937        } else if buffer_offset > region.buffer.len() {
3938            return None;
3939        }
3940        // remove this assert once we figure out the cause of the panics for #40453
3941        region
3942            .buffer
3943            .text
3944            .as_rope()
3945            .assert_char_boundary(buffer_offset);
3946        Some((region.buffer, buffer_offset))
3947    }
3948
3949    pub fn point_to_buffer_point(
3950        &self,
3951        point: Point,
3952    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
3953        let mut cursor = self.cursor::<Point>();
3954        cursor.seek(&point);
3955        let region = cursor.region()?;
3956        let overshoot = point - region.range.start;
3957        let buffer_point = region.buffer_range.start + overshoot;
3958        let excerpt = cursor.excerpt()?;
3959        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
3960            && region.has_trailing_newline
3961            && !region.is_main_buffer
3962        {
3963            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
3964        } else if buffer_point > region.buffer.max_point() {
3965            return None;
3966        }
3967        Some((region.buffer, buffer_point, excerpt.id))
3968    }
3969
3970    pub fn suggested_indents(
3971        &self,
3972        rows: impl IntoIterator<Item = u32>,
3973        cx: &App,
3974    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3975        let mut result = BTreeMap::new();
3976
3977        let mut rows_for_excerpt = Vec::new();
3978        let mut cursor = self.cursor::<Point>();
3979        let mut rows = rows.into_iter().peekable();
3980        let mut prev_row = u32::MAX;
3981        let mut prev_language_indent_size = IndentSize::default();
3982
3983        while let Some(row) = rows.next() {
3984            cursor.seek(&Point::new(row, 0));
3985            let Some(region) = cursor.region() else {
3986                continue;
3987            };
3988
3989            // Retrieve the language and indent size once for each disjoint region being indented.
3990            let single_indent_size = if row.saturating_sub(1) == prev_row {
3991                prev_language_indent_size
3992            } else {
3993                region
3994                    .buffer
3995                    .language_indent_size_at(Point::new(row, 0), cx)
3996            };
3997            prev_language_indent_size = single_indent_size;
3998            prev_row = row;
3999
4000            let start_buffer_row = region.buffer_range.start.row;
4001            let start_multibuffer_row = region.range.start.row;
4002            let end_multibuffer_row = region.range.end.row;
4003
4004            rows_for_excerpt.push(row);
4005            while let Some(next_row) = rows.peek().copied() {
4006                if end_multibuffer_row > next_row {
4007                    rows_for_excerpt.push(next_row);
4008                    rows.next();
4009                } else {
4010                    break;
4011                }
4012            }
4013
4014            let buffer_rows = rows_for_excerpt
4015                .drain(..)
4016                .map(|row| start_buffer_row + row - start_multibuffer_row);
4017            let buffer_indents = region
4018                .buffer
4019                .suggested_indents(buffer_rows, single_indent_size);
4020            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4021                (
4022                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4023                    indent,
4024                )
4025            });
4026            result.extend(multibuffer_indents);
4027        }
4028
4029        result
4030    }
4031
4032    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4033        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4034            let mut size = buffer.indent_size_for_line(range.start.row);
4035            size.len = size
4036                .len
4037                .min(range.end.column)
4038                .saturating_sub(range.start.column);
4039            size
4040        } else {
4041            IndentSize::spaces(0)
4042        }
4043    }
4044
4045    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4046        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4047            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4048        } else {
4049            LineIndent::spaces(0)
4050        }
4051    }
4052
4053    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4054        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4055
4056        if self.language_settings(cx).extend_comment_on_newline
4057            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4058        {
4059            let delimiters = language_scope.line_comment_prefixes();
4060            for delimiter in delimiters {
4061                if *self
4062                    .chars_at(Point::new(row.0, indent.len() as u32))
4063                    .take(delimiter.chars().count())
4064                    .collect::<String>()
4065                    .as_str()
4066                    == **delimiter
4067                {
4068                    indent.push_str(delimiter);
4069                    break;
4070                }
4071            }
4072        }
4073
4074        indent
4075    }
4076
4077    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4078    where
4079        T: ToOffset,
4080    {
4081        for char in self.reversed_chars_at(position) {
4082            if !char.is_whitespace() {
4083                return false;
4084            }
4085            if char == '\n' {
4086                return true;
4087            }
4088        }
4089        true
4090    }
4091
4092    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4093        while row.0 > 0 {
4094            row.0 -= 1;
4095            if !self.is_line_blank(row) {
4096                return Some(row);
4097            }
4098        }
4099        None
4100    }
4101
4102    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4103        if let Some((_, range)) = self.buffer_line_for_row(row) {
4104            range.end.column - range.start.column
4105        } else {
4106            0
4107        }
4108    }
4109
4110    pub fn buffer_line_for_row(
4111        &self,
4112        row: MultiBufferRow,
4113    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4114        let mut cursor = self.cursor::<Point>();
4115        let point = Point::new(row.0, 0);
4116        cursor.seek(&point);
4117        let region = cursor.region()?;
4118        let overshoot = point.min(region.range.end) - region.range.start;
4119        let buffer_point = region.buffer_range.start + overshoot;
4120        if buffer_point.row > region.buffer_range.end.row {
4121            return None;
4122        }
4123        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4124        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4125            .min(region.buffer_range.end);
4126        Some((region.buffer, line_start..line_end))
4127    }
4128
4129    pub fn max_point(&self) -> Point {
4130        self.text_summary().lines
4131    }
4132
4133    pub fn max_row(&self) -> MultiBufferRow {
4134        MultiBufferRow(self.text_summary().lines.row)
4135    }
4136
4137    pub fn text_summary(&self) -> TextSummary {
4138        self.diff_transforms.summary().output
4139    }
4140
4141    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4142    where
4143        D: TextDimension,
4144        O: ToOffset,
4145    {
4146        let range = range.start.to_offset(self)..range.end.to_offset(self);
4147        let mut cursor = self
4148            .diff_transforms
4149            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4150        cursor.seek(&range.start, Bias::Right);
4151
4152        let Some(first_transform) = cursor.item() else {
4153            return D::from_text_summary(&TextSummary::default());
4154        };
4155
4156        let diff_transform_start = cursor.start().0;
4157        let diff_transform_end = cursor.end().0;
4158        let diff_start = range.start;
4159        let start_overshoot = diff_start - diff_transform_start;
4160        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4161
4162        let mut result = match first_transform {
4163            DiffTransform::BufferContent { .. } => {
4164                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4165                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4166                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4167            }
4168            DiffTransform::DeletedHunk {
4169                buffer_id,
4170                base_text_byte_range,
4171                has_trailing_newline,
4172                ..
4173            } => {
4174                let buffer_start = base_text_byte_range.start + start_overshoot;
4175                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4176                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4177                    panic!("{:?} is in non-existent deleted hunk", range.start)
4178                };
4179
4180                let include_trailing_newline =
4181                    *has_trailing_newline && range.end >= diff_transform_end;
4182                if include_trailing_newline {
4183                    buffer_end -= 1;
4184                }
4185
4186                let mut summary =
4187                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4188
4189                if include_trailing_newline {
4190                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4191                }
4192
4193                summary
4194            }
4195        };
4196        if range.end < diff_transform_end {
4197            return result;
4198        }
4199
4200        cursor.next();
4201        result.add_assign(&D::from_text_summary(
4202            &cursor.summary(&range.end, Bias::Right),
4203        ));
4204
4205        let Some(last_transform) = cursor.item() else {
4206            return result;
4207        };
4208
4209        let overshoot = range.end - cursor.start().0;
4210        let suffix = match last_transform {
4211            DiffTransform::BufferContent { .. } => {
4212                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4213                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4214            }
4215            DiffTransform::DeletedHunk {
4216                base_text_byte_range,
4217                buffer_id,
4218                has_trailing_newline,
4219                ..
4220            } => {
4221                let buffer_end = base_text_byte_range.start + overshoot;
4222                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4223                    panic!("{:?} is in non-existent deleted hunk", range.end)
4224                };
4225
4226                let mut suffix = base_text
4227                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4228                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4229                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4230                }
4231                suffix
4232            }
4233        };
4234
4235        result.add_assign(&suffix);
4236        result
4237    }
4238
4239    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4240    where
4241        D: TextDimension,
4242    {
4243        let mut summary = D::zero(());
4244        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4245        cursor.seek(&range.start, Bias::Right);
4246        if let Some(excerpt) = cursor.item() {
4247            let mut end_before_newline = cursor.end();
4248            if excerpt.has_trailing_newline {
4249                end_before_newline -= ExcerptOffset::new(1);
4250            }
4251
4252            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4253            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4254            let end_in_excerpt =
4255                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4256            summary.add_assign(
4257                &excerpt
4258                    .buffer
4259                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4260            );
4261
4262            if range.end > end_before_newline {
4263                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4264            }
4265
4266            cursor.next();
4267        }
4268
4269        if range.end > *cursor.start() {
4270            summary.add_assign(
4271                &cursor
4272                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4273                    .0,
4274            );
4275            if let Some(excerpt) = cursor.item() {
4276                range.end = cmp::max(*cursor.start(), range.end);
4277
4278                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4279                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4280                summary.add_assign(
4281                    &excerpt
4282                        .buffer
4283                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4284                );
4285            }
4286        }
4287
4288        summary
4289    }
4290
4291    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4292    where
4293        D: TextDimension + Ord + Sub<D, Output = D>,
4294    {
4295        self.summaries_for_anchors([anchor])[0]
4296    }
4297
4298    fn resolve_summary_for_anchor<D>(
4299        &self,
4300        anchor: &Anchor,
4301        excerpt_position: D,
4302        diff_transforms: &mut Cursor<
4303            DiffTransform,
4304            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4305        >,
4306    ) -> D
4307    where
4308        D: TextDimension + Ord + Sub<D, Output = D>,
4309    {
4310        loop {
4311            let transform_end_position = diff_transforms.end().0.0;
4312            let at_transform_end =
4313                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4314            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4315                diff_transforms.next();
4316                continue;
4317            }
4318
4319            let mut position = diff_transforms.start().1.0;
4320            match diff_transforms.item() {
4321                Some(DiffTransform::DeletedHunk {
4322                    buffer_id,
4323                    base_text_byte_range,
4324                    ..
4325                }) => {
4326                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4327                        && let Some(base_text) =
4328                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4329                        && base_text.can_resolve(diff_base_anchor)
4330                    {
4331                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4332                        if base_text_offset >= base_text_byte_range.start
4333                            && base_text_offset <= base_text_byte_range.end
4334                        {
4335                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4336                                base_text_byte_range.start..base_text_offset,
4337                            );
4338                            position.add_assign(&position_in_hunk);
4339                        } else if at_transform_end {
4340                            diff_transforms.next();
4341                            continue;
4342                        }
4343                    }
4344                }
4345                _ => {
4346                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4347                        diff_transforms.next();
4348                        continue;
4349                    }
4350                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4351                    position.add_assign(&overshoot);
4352                }
4353            }
4354
4355            return position;
4356        }
4357    }
4358
4359    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4360        let mut cursor = self
4361            .excerpts
4362            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4363        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4364
4365        cursor.seek(&Some(locator), Bias::Left);
4366        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4367            cursor.prev();
4368        }
4369
4370        let mut position = cursor.start().1;
4371        if let Some(excerpt) = cursor.item()
4372            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4373        {
4374            let excerpt_buffer_start = excerpt
4375                .buffer
4376                .offset_for_anchor(&excerpt.range.context.start);
4377            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4378            let buffer_position = cmp::min(
4379                excerpt_buffer_end,
4380                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4381            );
4382            if buffer_position > excerpt_buffer_start {
4383                position.value += buffer_position - excerpt_buffer_start;
4384            }
4385        }
4386        position
4387    }
4388
4389    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4390        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4391            excerpt_id = *replacement;
4392        }
4393        excerpt_id
4394    }
4395
4396    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4397    where
4398        D: TextDimension + Ord + Sub<D, Output = D>,
4399        I: 'a + IntoIterator<Item = &'a Anchor>,
4400    {
4401        let mut anchors = anchors.into_iter().peekable();
4402        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4403        let mut diff_transforms_cursor = self
4404            .diff_transforms
4405            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(());
4406        diff_transforms_cursor.next();
4407
4408        let mut summaries = Vec::new();
4409        while let Some(anchor) = anchors.peek() {
4410            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4411
4412            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4413                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4414            });
4415
4416            let locator = self.excerpt_locator_for_id(excerpt_id);
4417            cursor.seek_forward(locator, Bias::Left);
4418            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4419                cursor.prev();
4420            }
4421
4422            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4423            if let Some(excerpt) = cursor.item() {
4424                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4425                    let position = self.resolve_summary_for_anchor(
4426                        &Anchor::min(),
4427                        excerpt_start_position,
4428                        &mut diff_transforms_cursor,
4429                    );
4430                    summaries.extend(excerpt_anchors.map(|_| position));
4431                    continue;
4432                }
4433                let excerpt_buffer_start =
4434                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4435                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4436                for (buffer_summary, anchor) in excerpt
4437                    .buffer
4438                    .summaries_for_anchors_with_payload::<D, _, _>(
4439                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4440                    )
4441                {
4442                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4443                    let mut position = excerpt_start_position;
4444                    if summary > excerpt_buffer_start {
4445                        position.add_assign(&(summary - excerpt_buffer_start));
4446                    }
4447
4448                    if position > diff_transforms_cursor.start().0.0 {
4449                        diff_transforms_cursor
4450                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4451                    }
4452
4453                    summaries.push(self.resolve_summary_for_anchor(
4454                        anchor,
4455                        position,
4456                        &mut diff_transforms_cursor,
4457                    ));
4458                }
4459            } else {
4460                diff_transforms_cursor
4461                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4462                let position = self.resolve_summary_for_anchor(
4463                    &Anchor::max(),
4464                    excerpt_start_position,
4465                    &mut diff_transforms_cursor,
4466                );
4467                summaries.extend(excerpt_anchors.map(|_| position));
4468            }
4469        }
4470
4471        summaries
4472    }
4473
4474    pub fn dimensions_from_points<'a, D>(
4475        &'a self,
4476        points: impl 'a + IntoIterator<Item = Point>,
4477    ) -> impl 'a + Iterator<Item = D>
4478    where
4479        D: TextDimension + Sub<D, Output = D>,
4480    {
4481        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4482        cursor.seek(&DimensionPair {
4483            key: Point::default(),
4484            value: None,
4485        });
4486        let mut points = points.into_iter();
4487        iter::from_fn(move || {
4488            let point = points.next()?;
4489
4490            cursor.seek_forward(&DimensionPair {
4491                key: point,
4492                value: None,
4493            });
4494
4495            if let Some(region) = cursor.region() {
4496                let overshoot = point - region.range.start.key;
4497                let buffer_point = region.buffer_range.start.key + overshoot;
4498                let mut position = region.range.start.value.unwrap();
4499                position.add_assign(
4500                    &region
4501                        .buffer
4502                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4503                );
4504                if point == region.range.end.key && region.has_trailing_newline {
4505                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4506                }
4507                Some(position)
4508            } else {
4509                Some(D::from_text_summary(&self.text_summary()))
4510            }
4511        })
4512    }
4513
4514    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4515    where
4516        I: 'a + IntoIterator<Item = &'a Anchor>,
4517    {
4518        let mut anchors = anchors.into_iter().enumerate().peekable();
4519        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4520        cursor.next();
4521
4522        let mut result = Vec::new();
4523
4524        while let Some((_, anchor)) = anchors.peek() {
4525            let old_excerpt_id = anchor.excerpt_id;
4526
4527            // Find the location where this anchor's excerpt should be.
4528            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4529            cursor.seek_forward(&Some(old_locator), Bias::Left);
4530
4531            let next_excerpt = cursor.item();
4532            let prev_excerpt = cursor.prev_item();
4533
4534            // Process all of the anchors for this excerpt.
4535            while let Some((anchor_ix, &anchor)) =
4536                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4537            {
4538                let mut anchor = anchor;
4539
4540                // Leave min and max anchors unchanged if invalid or
4541                // if the old excerpt still exists at this location
4542                let mut kept_position = next_excerpt
4543                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4544                    || old_excerpt_id == ExcerptId::max()
4545                    || old_excerpt_id == ExcerptId::min();
4546
4547                // If the old excerpt no longer exists at this location, then attempt to
4548                // find an equivalent position for this anchor in an adjacent excerpt.
4549                if !kept_position {
4550                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4551                        if excerpt.contains(&anchor) {
4552                            anchor.excerpt_id = excerpt.id;
4553                            kept_position = true;
4554                            break;
4555                        }
4556                    }
4557                }
4558
4559                // If there's no adjacent excerpt that contains the anchor's position,
4560                // then report that the anchor has lost its position.
4561                if !kept_position {
4562                    anchor = if let Some(excerpt) = next_excerpt {
4563                        let mut text_anchor = excerpt
4564                            .range
4565                            .context
4566                            .start
4567                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4568                        if text_anchor
4569                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4570                            .is_gt()
4571                        {
4572                            text_anchor = excerpt.range.context.end;
4573                        }
4574                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4575                    } else if let Some(excerpt) = prev_excerpt {
4576                        let mut text_anchor = excerpt
4577                            .range
4578                            .context
4579                            .end
4580                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4581                        if text_anchor
4582                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4583                            .is_lt()
4584                        {
4585                            text_anchor = excerpt.range.context.start;
4586                        }
4587                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4588                    } else if anchor.text_anchor.bias == Bias::Left {
4589                        Anchor::min()
4590                    } else {
4591                        Anchor::max()
4592                    };
4593                }
4594
4595                result.push((anchor_ix, anchor, kept_position));
4596            }
4597        }
4598        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4599        result
4600    }
4601
4602    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4603        self.anchor_at(position, Bias::Left)
4604    }
4605
4606    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4607        self.anchor_at(position, Bias::Right)
4608    }
4609
4610    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4611        let offset = position.to_offset(self);
4612
4613        // Find the given position in the diff transforms. Determine the corresponding
4614        // offset in the excerpts, and whether the position is within a deleted hunk.
4615        let mut diff_transforms = self
4616            .diff_transforms
4617            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4618        diff_transforms.seek(&offset, Bias::Right);
4619
4620        if offset == diff_transforms.start().0
4621            && bias == Bias::Left
4622            && let Some(prev_item) = diff_transforms.prev_item()
4623            && let DiffTransform::DeletedHunk { .. } = prev_item
4624        {
4625            diff_transforms.prev();
4626        }
4627        let offset_in_transform = offset - diff_transforms.start().0;
4628        let mut excerpt_offset = diff_transforms.start().1;
4629        let mut diff_base_anchor = None;
4630        if let Some(DiffTransform::DeletedHunk {
4631            buffer_id,
4632            base_text_byte_range,
4633            has_trailing_newline,
4634            ..
4635        }) = diff_transforms.item()
4636        {
4637            let diff = self.diffs.get(buffer_id).expect("missing diff");
4638            if offset_in_transform > base_text_byte_range.len() {
4639                debug_assert!(*has_trailing_newline);
4640                bias = Bias::Right;
4641            } else {
4642                diff_base_anchor = Some(
4643                    diff.base_text()
4644                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4645                );
4646                bias = Bias::Left;
4647            }
4648        } else {
4649            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4650        };
4651
4652        let mut excerpts = self
4653            .excerpts
4654            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
4655        excerpts.seek(&excerpt_offset, Bias::Right);
4656        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4657            excerpts.prev();
4658        }
4659        if let Some(excerpt) = excerpts.item() {
4660            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4661            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
4662                overshoot -= 1;
4663                bias = Bias::Right;
4664            }
4665
4666            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4667            let text_anchor =
4668                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4669            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
4670            match diff_base_anchor {
4671                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
4672                None => anchor,
4673            }
4674        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4675            Anchor::min()
4676        } else {
4677            Anchor::max()
4678        }
4679    }
4680
4681    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
4682    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
4683        let (excerpt, buffer, _) = self.as_singleton()?;
4684        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
4685    }
4686
4687    /// Returns an anchor for the given excerpt and text anchor,
4688    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4689    pub fn anchor_range_in_excerpt(
4690        &self,
4691        excerpt_id: ExcerptId,
4692        text_anchor: Range<text::Anchor>,
4693    ) -> Option<Range<Anchor>> {
4694        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4695        let excerpt = self.excerpt(excerpt_id)?;
4696
4697        Some(
4698            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
4699                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
4700        )
4701    }
4702
4703    /// Returns an anchor for the given excerpt and text anchor,
4704    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4705    pub fn anchor_in_excerpt(
4706        &self,
4707        excerpt_id: ExcerptId,
4708        text_anchor: text::Anchor,
4709    ) -> Option<Anchor> {
4710        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4711        let excerpt = self.excerpt(excerpt_id)?;
4712        self.anchor_in_excerpt_(excerpt, text_anchor)
4713    }
4714
4715    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
4716        match text_anchor.buffer_id {
4717            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
4718            Some(_) => return None,
4719            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
4720                return Some(Anchor::in_buffer(
4721                    excerpt.id,
4722                    excerpt.buffer_id,
4723                    text_anchor,
4724                ));
4725            }
4726            None => return None,
4727        }
4728
4729        let context = &excerpt.range.context;
4730        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
4731            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
4732        {
4733            return None;
4734        }
4735
4736        Some(Anchor::in_buffer(
4737            excerpt.id,
4738            excerpt.buffer_id,
4739            text_anchor,
4740        ))
4741    }
4742
4743    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4744        Some(self.excerpt(excerpt_id)?.range.context.clone())
4745    }
4746
4747    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4748        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4749            true
4750        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4751            excerpt.buffer.can_resolve(&anchor.text_anchor)
4752        } else {
4753            false
4754        }
4755    }
4756
4757    pub fn excerpts(
4758        &self,
4759    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4760        self.excerpts
4761            .iter()
4762            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4763    }
4764
4765    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
4766        let excerpts = self.excerpts.cursor(());
4767        let diff_transforms = self.diff_transforms.cursor(());
4768        MultiBufferCursor {
4769            excerpts,
4770            diff_transforms,
4771            diffs: &self.diffs,
4772            cached_region: None,
4773        }
4774    }
4775
4776    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4777        let start_locator = self.excerpt_locator_for_id(excerpt_id);
4778        let mut excerpts = self
4779            .excerpts
4780            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
4781        excerpts.seek(&Some(start_locator), Bias::Left);
4782        excerpts.prev();
4783
4784        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(());
4785        diff_transforms.seek(&excerpts.start().1, Bias::Left);
4786        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
4787            diff_transforms.next();
4788        }
4789
4790        let excerpt = excerpts.item()?;
4791        Some(MultiBufferExcerpt {
4792            excerpt,
4793            offset: diff_transforms.start().output_dimension.0,
4794            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4795            excerpt_offset: excerpts.start().1.clone(),
4796            diff_transforms,
4797        })
4798    }
4799
4800    pub fn excerpt_boundaries_in_range<R, T>(
4801        &self,
4802        range: R,
4803    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4804    where
4805        R: RangeBounds<T>,
4806        T: ToOffset,
4807    {
4808        let start_offset;
4809        let start = match range.start_bound() {
4810            Bound::Included(start) => {
4811                start_offset = start.to_offset(self);
4812                Bound::Included(start_offset)
4813            }
4814            Bound::Excluded(_) => {
4815                panic!("not supported")
4816            }
4817            Bound::Unbounded => {
4818                start_offset = 0;
4819                Bound::Unbounded
4820            }
4821        };
4822        let end = match range.end_bound() {
4823            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4824            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4825            Bound::Unbounded => Bound::Unbounded,
4826        };
4827        let bounds = (start, end);
4828
4829        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4830        cursor.seek(&DimensionPair {
4831            key: start_offset,
4832            value: None,
4833        });
4834
4835        if cursor
4836            .region()
4837            .is_some_and(|region| bounds.contains(&region.range.start.key))
4838        {
4839            cursor.prev_excerpt();
4840        } else {
4841            cursor.seek_to_start_of_current_excerpt();
4842        }
4843        let mut prev_region = cursor.region();
4844
4845        cursor.next_excerpt();
4846
4847        iter::from_fn(move || {
4848            loop {
4849                if self.singleton {
4850                    return None;
4851                }
4852
4853                let next_region = cursor.region()?;
4854                cursor.next_excerpt();
4855                if !bounds.contains(&next_region.range.start.key) {
4856                    prev_region = Some(next_region);
4857                    continue;
4858                }
4859
4860                let next_region_start = next_region.range.start.value.unwrap();
4861                let next_region_end = if let Some(region) = cursor.region() {
4862                    region.range.start.value.unwrap()
4863                } else {
4864                    self.max_point()
4865                };
4866
4867                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4868                    id: region.excerpt.id,
4869                    buffer: region.excerpt.buffer.clone(),
4870                    buffer_id: region.excerpt.buffer_id,
4871                    range: region.excerpt.range.clone(),
4872                    end_row: MultiBufferRow(next_region_start.row),
4873                });
4874
4875                let next = ExcerptInfo {
4876                    id: next_region.excerpt.id,
4877                    buffer: next_region.excerpt.buffer.clone(),
4878                    buffer_id: next_region.excerpt.buffer_id,
4879                    range: next_region.excerpt.range.clone(),
4880                    end_row: if next_region.excerpt.has_trailing_newline {
4881                        MultiBufferRow(next_region_end.row - 1)
4882                    } else {
4883                        MultiBufferRow(next_region_end.row)
4884                    },
4885                };
4886
4887                let row = MultiBufferRow(next_region_start.row);
4888
4889                prev_region = Some(next_region);
4890
4891                return Some(ExcerptBoundary { row, prev, next });
4892            }
4893        })
4894    }
4895
4896    pub fn edit_count(&self) -> usize {
4897        self.edit_count
4898    }
4899
4900    pub fn non_text_state_update_count(&self) -> usize {
4901        self.non_text_state_update_count
4902    }
4903
4904    /// Returns the smallest enclosing bracket ranges containing the given range or
4905    /// None if no brackets contain range or the range is not contained in a single
4906    /// excerpt
4907    ///
4908    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4909    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4910        &self,
4911        range: Range<T>,
4912        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4913    ) -> Option<(Range<usize>, Range<usize>)> {
4914        let range = range.start.to_offset(self)..range.end.to_offset(self);
4915        let mut excerpt = self.excerpt_containing(range.clone())?;
4916        let buffer = excerpt.buffer();
4917        let excerpt_buffer_range = excerpt.buffer_range();
4918
4919        // Filter to ranges contained in the excerpt
4920        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4921            excerpt_buffer_range.contains(&open.start)
4922                && excerpt_buffer_range.contains(&close.end)
4923                && range_filter.is_none_or(|filter| filter(buffer, open, close))
4924        };
4925
4926        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4927            excerpt.map_range_to_buffer(range),
4928            Some(&range_filter),
4929        )?;
4930
4931        Some((
4932            excerpt.map_range_from_buffer(open),
4933            excerpt.map_range_from_buffer(close),
4934        ))
4935    }
4936
4937    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4938    /// not contained in a single excerpt
4939    pub fn enclosing_bracket_ranges<T: ToOffset>(
4940        &self,
4941        range: Range<T>,
4942    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4943        let range = range.start.to_offset(self)..range.end.to_offset(self);
4944        let mut excerpt = self.excerpt_containing(range.clone())?;
4945
4946        Some(
4947            excerpt
4948                .buffer()
4949                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4950                .filter_map(move |pair| {
4951                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
4952                        Some((
4953                            excerpt.map_range_from_buffer(pair.open_range),
4954                            excerpt.map_range_from_buffer(pair.close_range),
4955                        ))
4956                    } else {
4957                        None
4958                    }
4959                }),
4960        )
4961    }
4962
4963    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4964    /// not contained in a single excerpt
4965    pub fn text_object_ranges<T: ToOffset>(
4966        &self,
4967        range: Range<T>,
4968        options: TreeSitterOptions,
4969    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4970        let range = range.start.to_offset(self)..range.end.to_offset(self);
4971        self.excerpt_containing(range.clone())
4972            .map(|mut excerpt| {
4973                excerpt
4974                    .buffer()
4975                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4976                    .filter_map(move |(range, text_object)| {
4977                        if excerpt.contains_buffer_range(range.clone()) {
4978                            Some((excerpt.map_range_from_buffer(range), text_object))
4979                        } else {
4980                            None
4981                        }
4982                    })
4983            })
4984            .into_iter()
4985            .flatten()
4986    }
4987
4988    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4989    /// not contained in a single excerpt
4990    pub fn bracket_ranges<T: ToOffset>(
4991        &self,
4992        range: Range<T>,
4993    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4994        let range = range.start.to_offset(self)..range.end.to_offset(self);
4995        let mut excerpt = self.excerpt_containing(range.clone())?;
4996
4997        Some(
4998            excerpt
4999                .buffer()
5000                .bracket_ranges(excerpt.map_range_to_buffer(range))
5001                .filter_map(move |pair| {
5002                    let buffer_range = pair.open_range.start..pair.close_range.end;
5003                    if excerpt.contains_buffer_range(buffer_range) {
5004                        Some((
5005                            excerpt.map_range_from_buffer(pair.open_range),
5006                            excerpt.map_range_from_buffer(pair.close_range),
5007                        ))
5008                    } else {
5009                        None
5010                    }
5011                }),
5012        )
5013    }
5014
5015    pub fn redacted_ranges<'a, T: ToOffset>(
5016        &'a self,
5017        range: Range<T>,
5018        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5019    ) -> impl Iterator<Item = Range<usize>> + 'a {
5020        let range = range.start.to_offset(self)..range.end.to_offset(self);
5021        self.lift_buffer_metadata(range, move |buffer, range| {
5022            if redaction_enabled(buffer.file()) {
5023                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5024            } else {
5025                None
5026            }
5027        })
5028        .map(|(range, _, _)| range)
5029    }
5030
5031    pub fn runnable_ranges(
5032        &self,
5033        range: Range<Anchor>,
5034    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5035        let range = range.start.to_offset(self)..range.end.to_offset(self);
5036        self.lift_buffer_metadata(range, move |buffer, range| {
5037            Some(
5038                buffer
5039                    .runnable_ranges(range.clone())
5040                    .filter(move |runnable| {
5041                        runnable.run_range.start >= range.start
5042                            && runnable.run_range.end < range.end
5043                    })
5044                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5045            )
5046        })
5047        .map(|(run_range, runnable, _)| language::RunnableRange {
5048            run_range,
5049            ..runnable
5050        })
5051    }
5052
5053    pub fn line_indents(
5054        &self,
5055        start_row: MultiBufferRow,
5056        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5057    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5058        let max_point = self.max_point();
5059        let mut cursor = self.cursor::<Point>();
5060        cursor.seek(&Point::new(start_row.0, 0));
5061        iter::from_fn(move || {
5062            let mut region = cursor.region()?;
5063            while !buffer_filter(&region.excerpt.buffer) {
5064                cursor.next();
5065                region = cursor.region()?;
5066            }
5067            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5068            let buffer_start_row =
5069                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5070
5071            let buffer_end_row = if region.is_main_buffer
5072                && (region.has_trailing_newline || region.range.end == max_point)
5073            {
5074                region.buffer_range.end.row
5075            } else {
5076                region.buffer_range.end.row.saturating_sub(1)
5077            };
5078
5079            let line_indents = region
5080                .buffer
5081                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5082            cursor.next();
5083            Some(line_indents.map(move |(buffer_row, indent)| {
5084                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5085                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5086            }))
5087        })
5088        .flatten()
5089    }
5090
5091    pub fn reversed_line_indents(
5092        &self,
5093        end_row: MultiBufferRow,
5094        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5095    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5096        let max_point = self.max_point();
5097        let mut cursor = self.cursor::<Point>();
5098        cursor.seek(&Point::new(end_row.0, 0));
5099        iter::from_fn(move || {
5100            let mut region = cursor.region()?;
5101            while !buffer_filter(&region.excerpt.buffer) {
5102                cursor.prev();
5103                region = cursor.region()?;
5104            }
5105
5106            let buffer_start_row = region.buffer_range.start.row;
5107            let buffer_end_row = if region.is_main_buffer
5108                && (region.has_trailing_newline || region.range.end == max_point)
5109            {
5110                region.buffer_range.end.row + 1
5111            } else {
5112                region.buffer_range.end.row
5113            };
5114
5115            let overshoot = end_row.0 - region.range.start.row;
5116            let buffer_end_row =
5117                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5118
5119            let line_indents = region
5120                .buffer
5121                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5122            cursor.prev();
5123            Some(line_indents.map(move |(buffer_row, indent)| {
5124                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5125                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5126            }))
5127        })
5128        .flatten()
5129    }
5130
5131    pub async fn enclosing_indent(
5132        &self,
5133        mut target_row: MultiBufferRow,
5134    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5135        let max_row = MultiBufferRow(self.max_point().row);
5136        if target_row >= max_row {
5137            return None;
5138        }
5139
5140        let mut target_indent = self.line_indent_for_row(target_row);
5141
5142        // If the current row is at the start of an indented block, we want to return this
5143        // block as the enclosing indent.
5144        if !target_indent.is_line_empty() && target_row < max_row {
5145            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5146            if !next_line_indent.is_line_empty()
5147                && target_indent.raw_len() < next_line_indent.raw_len()
5148            {
5149                target_indent = next_line_indent;
5150                target_row.0 += 1;
5151            }
5152        }
5153
5154        const SEARCH_ROW_LIMIT: u32 = 25000;
5155        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5156        const YIELD_INTERVAL: u32 = 100;
5157
5158        let mut accessed_row_counter = 0;
5159
5160        // If there is a blank line at the current row, search for the next non indented lines
5161        if target_indent.is_line_empty() {
5162            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5163            let end =
5164                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5165
5166            let mut non_empty_line_above = None;
5167            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5168                if row < start {
5169                    break;
5170                }
5171                accessed_row_counter += 1;
5172                if accessed_row_counter == YIELD_INTERVAL {
5173                    accessed_row_counter = 0;
5174                    yield_now().await;
5175                }
5176                if !indent.is_line_empty() {
5177                    non_empty_line_above = Some((row, indent));
5178                    break;
5179                }
5180            }
5181
5182            let mut non_empty_line_below = None;
5183            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5184                if row > end {
5185                    break;
5186                }
5187                accessed_row_counter += 1;
5188                if accessed_row_counter == YIELD_INTERVAL {
5189                    accessed_row_counter = 0;
5190                    yield_now().await;
5191                }
5192                if !indent.is_line_empty() {
5193                    non_empty_line_below = Some((row, indent));
5194                    break;
5195                }
5196            }
5197
5198            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5199                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5200                    if above_indent.raw_len() >= below_indent.raw_len() {
5201                        (above_row, above_indent)
5202                    } else {
5203                        (below_row, below_indent)
5204                    }
5205                }
5206                (Some(above), None) => above,
5207                (None, Some(below)) => below,
5208                _ => return None,
5209            };
5210
5211            target_indent = indent;
5212            target_row = row;
5213        }
5214
5215        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5216        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5217
5218        let mut start_indent = None;
5219        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5220            if row < start {
5221                break;
5222            }
5223            accessed_row_counter += 1;
5224            if accessed_row_counter == YIELD_INTERVAL {
5225                accessed_row_counter = 0;
5226                yield_now().await;
5227            }
5228            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5229                start_indent = Some((row, indent));
5230                break;
5231            }
5232        }
5233        let (start_row, start_indent_size) = start_indent?;
5234
5235        let mut end_indent = (end, None);
5236        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5237            if row > end {
5238                break;
5239            }
5240            accessed_row_counter += 1;
5241            if accessed_row_counter == YIELD_INTERVAL {
5242                accessed_row_counter = 0;
5243                yield_now().await;
5244            }
5245            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5246                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5247                break;
5248            }
5249        }
5250        let (end_row, end_indent_size) = end_indent;
5251
5252        let indent = if let Some(end_indent_size) = end_indent_size {
5253            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5254                start_indent_size
5255            } else {
5256                end_indent_size
5257            }
5258        } else {
5259            start_indent_size
5260        };
5261
5262        Some((start_row..end_row, indent))
5263    }
5264
5265    pub fn indent_guides_in_range<T: ToPoint>(
5266        &self,
5267        range: Range<T>,
5268        ignore_disabled_for_language: bool,
5269        cx: &App,
5270    ) -> impl Iterator<Item = IndentGuide> {
5271        let range = range.start.to_point(self)..range.end.to_point(self);
5272        let start_row = MultiBufferRow(range.start.row);
5273        let end_row = MultiBufferRow(range.end.row);
5274
5275        let mut row_indents = self.line_indents(start_row, |buffer| {
5276            let settings =
5277                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5278            settings.indent_guides.enabled || ignore_disabled_for_language
5279        });
5280
5281        let mut result = Vec::new();
5282        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5283
5284        let mut prev_settings = None;
5285        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5286            if first_row > end_row {
5287                break;
5288            }
5289            let current_depth = indent_stack.len() as u32;
5290
5291            // Avoid retrieving the language settings repeatedly for every buffer row.
5292            if let Some((prev_buffer_id, _)) = &prev_settings
5293                && prev_buffer_id != &buffer.remote_id()
5294            {
5295                prev_settings.take();
5296            }
5297            let settings = &prev_settings
5298                .get_or_insert_with(|| {
5299                    (
5300                        buffer.remote_id(),
5301                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5302                    )
5303                })
5304                .1;
5305            let tab_size = settings.tab_size.get();
5306
5307            // When encountering empty, continue until found useful line indent
5308            // then add to the indent stack with the depth found
5309            let mut found_indent = false;
5310            let mut last_row = first_row;
5311            if line_indent.is_line_blank() {
5312                while !found_indent {
5313                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5314                        break;
5315                    };
5316                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5317                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5318                        break;
5319                    }
5320
5321                    if new_line_indent.is_line_blank() {
5322                        continue;
5323                    }
5324                    last_row = target_row.min(end_row);
5325                    line_indent = new_line_indent;
5326                    found_indent = true;
5327                    break;
5328                }
5329            } else {
5330                found_indent = true
5331            }
5332
5333            let depth = if found_indent {
5334                line_indent.len(tab_size) / tab_size
5335            } else {
5336                0
5337            };
5338
5339            match depth.cmp(&current_depth) {
5340                cmp::Ordering::Less => {
5341                    for _ in 0..(current_depth - depth) {
5342                        let mut indent = indent_stack.pop().unwrap();
5343                        if last_row != first_row {
5344                            // In this case, we landed on an empty row, had to seek forward,
5345                            // and discovered that the indent we where on is ending.
5346                            // This means that the last display row must
5347                            // be on line that ends this indent range, so we
5348                            // should display the range up to the first non-empty line
5349                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5350                        }
5351
5352                        result.push(indent)
5353                    }
5354                }
5355                cmp::Ordering::Greater => {
5356                    for next_depth in current_depth..depth {
5357                        indent_stack.push(IndentGuide {
5358                            buffer_id: buffer.remote_id(),
5359                            start_row: first_row,
5360                            end_row: last_row,
5361                            depth: next_depth,
5362                            tab_size,
5363                            settings: settings.indent_guides.clone(),
5364                        });
5365                    }
5366                }
5367                _ => {}
5368            }
5369
5370            for indent in indent_stack.iter_mut() {
5371                indent.end_row = last_row;
5372            }
5373        }
5374
5375        result.extend(indent_stack);
5376        result.into_iter()
5377    }
5378
5379    pub fn trailing_excerpt_update_count(&self) -> usize {
5380        self.trailing_excerpt_update_count
5381    }
5382
5383    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5384        self.point_to_buffer_offset(point)
5385            .and_then(|(buffer, _)| buffer.file())
5386    }
5387
5388    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5389        self.point_to_buffer_offset(point)
5390            .and_then(|(buffer, offset)| buffer.language_at(offset))
5391    }
5392
5393    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5394        self.excerpts
5395            .first()
5396            .map(|excerpt| &excerpt.buffer)
5397            .map(|buffer| {
5398                language_settings(
5399                    buffer.language().map(|language| language.name()),
5400                    buffer.file(),
5401                    cx,
5402                )
5403            })
5404            .unwrap_or_else(move || self.language_settings_at(0, cx))
5405    }
5406
5407    pub fn language_settings_at<'a, T: ToOffset>(
5408        &'a self,
5409        point: T,
5410        cx: &'a App,
5411    ) -> Cow<'a, LanguageSettings> {
5412        let mut language = None;
5413        let mut file = None;
5414        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5415            language = buffer.language_at(offset);
5416            file = buffer.file();
5417        }
5418        language_settings(language.map(|l| l.name()), file, cx)
5419    }
5420
5421    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5422        self.point_to_buffer_offset(point)
5423            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5424    }
5425
5426    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5427        self.point_to_buffer_offset(point)
5428            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5429            .unwrap_or_default()
5430    }
5431
5432    pub fn language_indent_size_at<T: ToOffset>(
5433        &self,
5434        position: T,
5435        cx: &App,
5436    ) -> Option<IndentSize> {
5437        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5438        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5439    }
5440
5441    pub fn is_dirty(&self) -> bool {
5442        self.is_dirty
5443    }
5444
5445    pub fn has_deleted_file(&self) -> bool {
5446        self.has_deleted_file
5447    }
5448
5449    pub fn has_conflict(&self) -> bool {
5450        self.has_conflict
5451    }
5452
5453    pub fn has_diagnostics(&self) -> bool {
5454        self.excerpts
5455            .iter()
5456            .any(|excerpt| excerpt.buffer.has_diagnostics())
5457    }
5458
5459    pub fn diagnostic_group(
5460        &self,
5461        buffer_id: BufferId,
5462        group_id: usize,
5463    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5464        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5465            if buffer.remote_id() != buffer_id {
5466                return None;
5467            };
5468            Some(
5469                buffer
5470                    .diagnostics_in_range(range, false)
5471                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5472                    .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5473            )
5474        })
5475        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5476    }
5477
5478    pub fn diagnostics_in_range<'a, T>(
5479        &'a self,
5480        range: Range<T>,
5481    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
5482    where
5483        T: 'a
5484            + text::ToOffset
5485            + text::FromAnchor
5486            + TextDimension
5487            + Ord
5488            + Sub<T, Output = T>
5489            + fmt::Debug,
5490    {
5491        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5492            Some(
5493                buffer
5494                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5495                    .map(|entry| (entry.range, entry.diagnostic)),
5496            )
5497        })
5498        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5499    }
5500
5501    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
5502        &'a self,
5503        range: Range<T>,
5504    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, T>)> + 'a
5505    where
5506        T: 'a
5507            + text::ToOffset
5508            + text::FromAnchor
5509            + TextDimension
5510            + Ord
5511            + Sub<T, Output = T>
5512            + fmt::Debug,
5513    {
5514        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5515            Some(
5516                buffer
5517                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5518                    .map(|entry| (entry.range, entry.diagnostic)),
5519            )
5520        })
5521        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5522    }
5523
5524    pub fn syntax_ancestor<T: ToOffset>(
5525        &self,
5526        range: Range<T>,
5527    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
5528        let range = range.start.to_offset(self)..range.end.to_offset(self);
5529        let mut excerpt = self.excerpt_containing(range.clone())?;
5530        let node = excerpt
5531            .buffer()
5532            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5533        let node_range = node.byte_range();
5534        if !excerpt.contains_buffer_range(node_range.clone()) {
5535            return None;
5536        };
5537        Some((node, excerpt.map_range_from_buffer(node_range)))
5538    }
5539
5540    pub fn syntax_next_sibling<T: ToOffset>(
5541        &self,
5542        range: Range<T>,
5543    ) -> Option<tree_sitter::Node<'_>> {
5544        let range = range.start.to_offset(self)..range.end.to_offset(self);
5545        let mut excerpt = self.excerpt_containing(range.clone())?;
5546        excerpt
5547            .buffer()
5548            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
5549    }
5550
5551    pub fn syntax_prev_sibling<T: ToOffset>(
5552        &self,
5553        range: Range<T>,
5554    ) -> Option<tree_sitter::Node<'_>> {
5555        let range = range.start.to_offset(self)..range.end.to_offset(self);
5556        let mut excerpt = self.excerpt_containing(range.clone())?;
5557        excerpt
5558            .buffer()
5559            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
5560    }
5561
5562    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5563        let (excerpt_id, _, buffer) = self.as_singleton()?;
5564        let outline = buffer.outline(theme);
5565        Some(Outline::new(
5566            outline
5567                .items
5568                .into_iter()
5569                .flat_map(|item| {
5570                    Some(OutlineItem {
5571                        depth: item.depth,
5572                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5573                        text: item.text,
5574                        highlight_ranges: item.highlight_ranges,
5575                        name_ranges: item.name_ranges,
5576                        body_range: item.body_range.and_then(|body_range| {
5577                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5578                        }),
5579                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5580                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5581                        }),
5582                    })
5583                })
5584                .collect(),
5585        ))
5586    }
5587
5588    pub fn symbols_containing<T: ToOffset>(
5589        &self,
5590        offset: T,
5591        theme: Option<&SyntaxTheme>,
5592    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5593        let anchor = self.anchor_before(offset);
5594        let excerpt_id = anchor.excerpt_id;
5595        let excerpt = self.excerpt(excerpt_id)?;
5596        let buffer_id = excerpt.buffer_id;
5597        Some((
5598            buffer_id,
5599            excerpt
5600                .buffer
5601                .symbols_containing(anchor.text_anchor, theme)
5602                .into_iter()
5603                .flat_map(|item| {
5604                    Some(OutlineItem {
5605                        depth: item.depth,
5606                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
5607                        text: item.text,
5608                        highlight_ranges: item.highlight_ranges,
5609                        name_ranges: item.name_ranges,
5610                        body_range: item.body_range.map(|body_range| {
5611                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5612                        }),
5613                        annotation_range: item.annotation_range.map(|body_range| {
5614                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5615                        }),
5616                    })
5617                })
5618                .collect(),
5619        ))
5620    }
5621
5622    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5623        if id == ExcerptId::min() {
5624            Locator::min_ref()
5625        } else if id == ExcerptId::max() {
5626            Locator::max_ref()
5627        } else {
5628            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
5629            if let Some(entry) = item
5630                && entry.id == id
5631            {
5632                return &entry.locator;
5633            }
5634            panic!("invalid excerpt id {id:?}")
5635        }
5636    }
5637
5638    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5639    fn excerpt_locators_for_ids(
5640        &self,
5641        ids: impl IntoIterator<Item = ExcerptId>,
5642    ) -> SmallVec<[Locator; 1]> {
5643        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5644        sorted_ids.sort_unstable();
5645        sorted_ids.dedup();
5646        let mut locators = SmallVec::new();
5647
5648        while sorted_ids.last() == Some(&ExcerptId::max()) {
5649            sorted_ids.pop();
5650            locators.push(Locator::max());
5651        }
5652
5653        let mut sorted_ids = sorted_ids.into_iter().peekable();
5654        locators.extend(
5655            sorted_ids
5656                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
5657                .map(|_| Locator::min()),
5658        );
5659
5660        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
5661        for id in sorted_ids {
5662            if cursor.seek_forward(&id, Bias::Left) {
5663                locators.push(cursor.item().unwrap().locator.clone());
5664            } else {
5665                panic!("invalid excerpt id {:?}", id);
5666            }
5667        }
5668
5669        locators.sort_unstable();
5670        locators
5671    }
5672
5673    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5674        Some(self.excerpt(excerpt_id)?.buffer_id)
5675    }
5676
5677    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5678        Some(&self.excerpt(excerpt_id)?.buffer)
5679    }
5680
5681    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5682        let mut cursor = self
5683            .excerpts
5684            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
5685        let locator = self.excerpt_locator_for_id(excerpt_id);
5686        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
5687        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5688            sought_exact = true;
5689            cursor.prev();
5690        } else if excerpt_id == ExcerptId::min() {
5691            sought_exact = true;
5692        }
5693        if sought_exact {
5694            let start = cursor.start().1.clone();
5695            let end = cursor.end().1;
5696            let mut diff_transforms = self
5697                .diff_transforms
5698                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
5699            diff_transforms.seek(&start, Bias::Left);
5700            let overshoot = start.0 - diff_transforms.start().0.0;
5701            let start = diff_transforms.start().1.0 + overshoot;
5702            diff_transforms.seek(&end, Bias::Right);
5703            let overshoot = end.0 - diff_transforms.start().0.0;
5704            let end = diff_transforms.start().1.0 + overshoot;
5705            Some(start..end)
5706        } else {
5707            None
5708        }
5709    }
5710
5711    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5712        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5713        let locator = self.excerpt_locator_for_id(excerpt_id);
5714        cursor.seek(&Some(locator), Bias::Left);
5715        if let Some(excerpt) = cursor.item()
5716            && excerpt.id == excerpt_id
5717        {
5718            return Some(excerpt);
5719        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5720            cursor.prev();
5721            return cursor.item();
5722        }
5723        None
5724    }
5725
5726    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5727    pub fn excerpt_containing<T: ToOffset>(
5728        &self,
5729        range: Range<T>,
5730    ) -> Option<MultiBufferExcerpt<'_>> {
5731        let range = range.start.to_offset(self)..range.end.to_offset(self);
5732        let mut cursor = self.cursor::<usize>();
5733        cursor.seek(&range.start);
5734
5735        let start_excerpt = cursor.excerpt()?;
5736        if range.end != range.start {
5737            cursor.seek_forward(&range.end);
5738            if cursor.excerpt()?.id != start_excerpt.id {
5739                return None;
5740            }
5741        }
5742
5743        cursor.seek_to_start_of_current_excerpt();
5744        let region = cursor.region()?;
5745        let offset = region.range.start;
5746        let buffer_offset = start_excerpt.buffer_start_offset();
5747        let excerpt_offset = cursor.excerpts.start().clone();
5748        Some(MultiBufferExcerpt {
5749            diff_transforms: cursor.diff_transforms,
5750            excerpt: start_excerpt,
5751            offset,
5752            buffer_offset,
5753            excerpt_offset,
5754        })
5755    }
5756
5757    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
5758        if let Some(id) = anchor.buffer_id {
5759            return Some(id);
5760        }
5761        let excerpt = self.excerpt_containing(anchor..anchor)?;
5762        Some(excerpt.buffer_id())
5763    }
5764
5765    pub fn selections_in_range<'a>(
5766        &'a self,
5767        range: &'a Range<Anchor>,
5768        include_local: bool,
5769    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5770        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5771        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5772        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5773        cursor.seek(start_locator, Bias::Left);
5774        cursor
5775            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5776            .flat_map(move |excerpt| {
5777                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5778                if excerpt.id == range.start.excerpt_id {
5779                    query_range.start = range.start.text_anchor;
5780                }
5781                if excerpt.id == range.end.excerpt_id {
5782                    query_range.end = range.end.text_anchor;
5783                }
5784
5785                excerpt
5786                    .buffer
5787                    .selections_in_range(query_range, include_local)
5788                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5789                        selections.map(move |selection| {
5790                            let mut start =
5791                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
5792                            let mut end =
5793                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
5794                            if range.start.cmp(&start, self).is_gt() {
5795                                start = range.start;
5796                            }
5797                            if range.end.cmp(&end, self).is_lt() {
5798                                end = range.end;
5799                            }
5800
5801                            (
5802                                replica_id,
5803                                line_mode,
5804                                cursor_shape,
5805                                Selection {
5806                                    id: selection.id,
5807                                    start,
5808                                    end,
5809                                    reversed: selection.reversed,
5810                                    goal: selection.goal,
5811                                },
5812                            )
5813                        })
5814                    })
5815            })
5816    }
5817
5818    pub fn show_headers(&self) -> bool {
5819        self.show_headers
5820    }
5821
5822    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5823        self.diffs.get(&buffer_id)
5824    }
5825
5826    /// Visually annotates a position or range with the `Debug` representation of a value. The
5827    /// callsite of this function is used as a key - previous annotations will be removed.
5828    #[cfg(debug_assertions)]
5829    #[track_caller]
5830    pub fn debug<V, R>(&self, ranges: &R, value: V)
5831    where
5832        R: debug::ToMultiBufferDebugRanges,
5833        V: std::fmt::Debug,
5834    {
5835        self.debug_with_key(std::panic::Location::caller(), ranges, value);
5836    }
5837
5838    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
5839    /// debug annotations with the same key will be removed. The key is also used to determine the
5840    /// annotation's color.
5841    #[cfg(debug_assertions)]
5842    #[track_caller]
5843    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
5844    where
5845        K: std::hash::Hash + 'static,
5846        R: debug::ToMultiBufferDebugRanges,
5847        V: std::fmt::Debug,
5848    {
5849        let text_ranges = ranges
5850            .to_multi_buffer_debug_ranges(self)
5851            .into_iter()
5852            .flat_map(|range| {
5853                self.range_to_buffer_ranges(range).into_iter().map(
5854                    |(buffer, range, _excerpt_id)| {
5855                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
5856                    },
5857                )
5858            })
5859            .collect();
5860        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
5861            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
5862        });
5863    }
5864}
5865
5866#[cfg(any(test, feature = "test-support"))]
5867impl MultiBufferSnapshot {
5868    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5869        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
5870        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
5871        start..end
5872    }
5873
5874    #[cfg(any(test, feature = "test-support"))]
5875    fn check_invariants(&self) {
5876        let excerpts = self.excerpts.items(());
5877        let excerpt_ids = self.excerpt_ids.items(());
5878
5879        for (ix, excerpt) in excerpts.iter().enumerate() {
5880            if ix == 0 {
5881                if excerpt.locator <= Locator::min() {
5882                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5883                }
5884            } else if excerpt.locator <= excerpts[ix - 1].locator {
5885                panic!("excerpts are out-of-order: {:?}", excerpts);
5886            }
5887        }
5888
5889        for (ix, entry) in excerpt_ids.iter().enumerate() {
5890            if ix == 0 {
5891                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
5892                    panic!("invalid first excerpt id {:?}", entry.id);
5893                }
5894            } else if entry.id <= excerpt_ids[ix - 1].id {
5895                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5896            }
5897        }
5898
5899        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5900            panic!(
5901                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5902                self.excerpts.summary().text.len,
5903                self.diff_transforms.summary().input,
5904                self.diff_transforms.items(()),
5905            );
5906        }
5907
5908        let mut prev_transform: Option<&DiffTransform> = None;
5909        for item in self.diff_transforms.iter() {
5910            if let DiffTransform::BufferContent {
5911                summary,
5912                inserted_hunk_info,
5913            } = item
5914            {
5915                if let Some(DiffTransform::BufferContent {
5916                    inserted_hunk_info: prev_inserted_hunk_info,
5917                    ..
5918                }) = prev_transform
5919                    && *inserted_hunk_info == *prev_inserted_hunk_info
5920                {
5921                    panic!(
5922                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5923                        self.diff_transforms.items(())
5924                    );
5925                }
5926                if summary.len == 0 && !self.is_empty() {
5927                    panic!("empty buffer content transform");
5928                }
5929            }
5930            prev_transform = Some(item);
5931        }
5932    }
5933}
5934
5935impl<'a, D> MultiBufferCursor<'a, D>
5936where
5937    D: TextDimension + Ord + Sub<D, Output = D>,
5938{
5939    fn seek(&mut self, position: &D) {
5940        self.cached_region.take();
5941        self.diff_transforms
5942            .seek(&OutputDimension(*position), Bias::Right);
5943        if self.diff_transforms.item().is_none()
5944            && *position == self.diff_transforms.start().output_dimension.0
5945        {
5946            self.diff_transforms.prev();
5947        }
5948
5949        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5950        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5951            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5952            excerpt_position.add_assign(&overshoot);
5953        }
5954
5955        self.excerpts
5956            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
5957        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5958            self.excerpts.prev();
5959        }
5960    }
5961
5962    fn seek_forward(&mut self, position: &D) {
5963        self.cached_region.take();
5964        self.diff_transforms
5965            .seek_forward(&OutputDimension(*position), Bias::Right);
5966        if self.diff_transforms.item().is_none()
5967            && *position == self.diff_transforms.start().output_dimension.0
5968        {
5969            self.diff_transforms.prev();
5970        }
5971
5972        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5973        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5974        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5975            excerpt_position.add_assign(&overshoot);
5976        }
5977
5978        self.excerpts
5979            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
5980        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5981            self.excerpts.prev();
5982        }
5983    }
5984
5985    fn next_excerpt(&mut self) {
5986        self.excerpts.next();
5987        self.seek_to_start_of_current_excerpt();
5988    }
5989
5990    fn prev_excerpt(&mut self) {
5991        self.excerpts.prev();
5992        self.seek_to_start_of_current_excerpt();
5993    }
5994
5995    fn seek_to_start_of_current_excerpt(&mut self) {
5996        self.cached_region.take();
5997        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
5998        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
5999            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6000            && self.diff_transforms.next_item().is_some()
6001        {
6002            self.diff_transforms.next();
6003        }
6004    }
6005
6006    fn next(&mut self) {
6007        self.cached_region.take();
6008        match self
6009            .diff_transforms
6010            .end()
6011            .excerpt_dimension
6012            .cmp(&self.excerpts.end())
6013        {
6014            cmp::Ordering::Less => self.diff_transforms.next(),
6015            cmp::Ordering::Greater => self.excerpts.next(),
6016            cmp::Ordering::Equal => {
6017                self.diff_transforms.next();
6018                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6019                    || self.diff_transforms.item().is_none()
6020                {
6021                    self.excerpts.next();
6022                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6023                    self.diff_transforms.item()
6024                    && self
6025                        .excerpts
6026                        .item()
6027                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6028                {
6029                    self.excerpts.next();
6030                }
6031            }
6032        }
6033    }
6034
6035    fn prev(&mut self) {
6036        self.cached_region.take();
6037        match self
6038            .diff_transforms
6039            .start()
6040            .excerpt_dimension
6041            .cmp(self.excerpts.start())
6042        {
6043            cmp::Ordering::Less => self.excerpts.prev(),
6044            cmp::Ordering::Greater => self.diff_transforms.prev(),
6045            cmp::Ordering::Equal => {
6046                self.diff_transforms.prev();
6047                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6048                    || self.diff_transforms.item().is_none()
6049                {
6050                    self.excerpts.prev();
6051                }
6052            }
6053        }
6054    }
6055
6056    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6057        if self.cached_region.is_none() {
6058            self.cached_region = self.build_region();
6059        }
6060        self.cached_region.clone()
6061    }
6062
6063    fn is_at_start_of_excerpt(&mut self) -> bool {
6064        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6065            return false;
6066        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6067            return true;
6068        }
6069
6070        self.diff_transforms.prev();
6071        let prev_transform = self.diff_transforms.item();
6072        self.diff_transforms.next();
6073
6074        prev_transform.is_none_or(|next_transform| {
6075            matches!(next_transform, DiffTransform::BufferContent { .. })
6076        })
6077    }
6078
6079    fn is_at_end_of_excerpt(&mut self) -> bool {
6080        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6081            return false;
6082        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6083            || self.diff_transforms.item().is_none()
6084        {
6085            return true;
6086        }
6087
6088        let next_transform = self.diff_transforms.next_item();
6089        next_transform.is_none_or(|next_transform| match next_transform {
6090            DiffTransform::BufferContent { .. } => true,
6091            DiffTransform::DeletedHunk { hunk_info, .. } => self
6092                .excerpts
6093                .item()
6094                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6095        })
6096    }
6097
6098    fn main_buffer_position(&self) -> Option<D> {
6099        let excerpt = self.excerpts.item()?;
6100        let buffer = &excerpt.buffer;
6101        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6102        let mut buffer_start = buffer_context_start;
6103        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6104        buffer_start.add_assign(&overshoot);
6105        Some(buffer_start)
6106    }
6107
6108    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6109        let excerpt = self.excerpts.item()?;
6110        match self.diff_transforms.item()? {
6111            DiffTransform::DeletedHunk {
6112                buffer_id,
6113                base_text_byte_range,
6114                has_trailing_newline,
6115                hunk_info,
6116                ..
6117            } => {
6118                let diff = self.diffs.get(buffer_id)?;
6119                let buffer = diff.base_text();
6120                let mut rope_cursor = buffer.as_rope().cursor(0);
6121                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6122                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6123                let mut buffer_end = buffer_start;
6124                buffer_end.add_assign(&buffer_range_len);
6125                let start = self.diff_transforms.start().output_dimension.0;
6126                let end = self.diff_transforms.end().output_dimension.0;
6127                Some(MultiBufferRegion {
6128                    buffer,
6129                    excerpt,
6130                    has_trailing_newline: *has_trailing_newline,
6131                    is_main_buffer: false,
6132                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6133                        hunk_info.hunk_secondary_status,
6134                    )),
6135                    buffer_range: buffer_start..buffer_end,
6136                    range: start..end,
6137                })
6138            }
6139            DiffTransform::BufferContent {
6140                inserted_hunk_info, ..
6141            } => {
6142                let buffer = &excerpt.buffer;
6143                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6144
6145                let mut start = self.diff_transforms.start().output_dimension.0;
6146                let mut buffer_start = buffer_context_start;
6147                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6148                    let overshoot =
6149                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6150                    start.add_assign(&overshoot);
6151                } else {
6152                    let overshoot =
6153                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6154                    buffer_start.add_assign(&overshoot);
6155                }
6156
6157                let mut end;
6158                let mut buffer_end;
6159                let has_trailing_newline;
6160                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6161                    let overshoot =
6162                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6163                    end = self.diff_transforms.end().output_dimension.0;
6164                    buffer_end = buffer_context_start;
6165                    buffer_end.add_assign(&overshoot);
6166                    has_trailing_newline = false;
6167                } else {
6168                    let overshoot =
6169                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6170                    end = self.diff_transforms.start().output_dimension.0;
6171                    end.add_assign(&overshoot);
6172                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6173                    has_trailing_newline = excerpt.has_trailing_newline;
6174                };
6175
6176                Some(MultiBufferRegion {
6177                    buffer,
6178                    excerpt,
6179                    has_trailing_newline,
6180                    is_main_buffer: true,
6181                    diff_hunk_status: inserted_hunk_info
6182                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6183                    buffer_range: buffer_start..buffer_end,
6184                    range: start..end,
6185                })
6186            }
6187        }
6188    }
6189
6190    fn excerpt(&self) -> Option<&'a Excerpt> {
6191        self.excerpts.item()
6192    }
6193}
6194
6195impl Excerpt {
6196    fn new(
6197        id: ExcerptId,
6198        locator: Locator,
6199        buffer_id: BufferId,
6200        buffer: BufferSnapshot,
6201        range: ExcerptRange<text::Anchor>,
6202        has_trailing_newline: bool,
6203    ) -> Self {
6204        Excerpt {
6205            id,
6206            locator,
6207            max_buffer_row: range.context.end.to_point(&buffer).row,
6208            text_summary: buffer
6209                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6210            buffer_id,
6211            buffer,
6212            range,
6213            has_trailing_newline,
6214        }
6215    }
6216
6217    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6218        let content_start = self.range.context.start.to_offset(&self.buffer);
6219        let chunks_start = content_start + range.start;
6220        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6221
6222        let has_footer = self.has_trailing_newline
6223            && range.start <= self.text_summary.len
6224            && range.end > self.text_summary.len;
6225
6226        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6227
6228        ExcerptChunks {
6229            excerpt_id: self.id,
6230            content_chunks,
6231            has_footer,
6232        }
6233    }
6234
6235    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6236        let content_start = self.range.context.start.to_offset(&self.buffer);
6237        let chunks_start = content_start + range.start;
6238        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6239        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6240        excerpt_chunks.has_footer = self.has_trailing_newline
6241            && range.start <= self.text_summary.len
6242            && range.end > self.text_summary.len;
6243    }
6244
6245    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6246        if text_anchor
6247            .cmp(&self.range.context.start, &self.buffer)
6248            .is_lt()
6249        {
6250            self.range.context.start
6251        } else if text_anchor
6252            .cmp(&self.range.context.end, &self.buffer)
6253            .is_gt()
6254        {
6255            self.range.context.end
6256        } else {
6257            text_anchor
6258        }
6259    }
6260
6261    fn contains(&self, anchor: &Anchor) -> bool {
6262        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6263            && self
6264                .range
6265                .context
6266                .start
6267                .cmp(&anchor.text_anchor, &self.buffer)
6268                .is_le()
6269            && self
6270                .range
6271                .context
6272                .end
6273                .cmp(&anchor.text_anchor, &self.buffer)
6274                .is_ge()
6275    }
6276
6277    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6278    fn buffer_start_offset(&self) -> usize {
6279        self.range.context.start.to_offset(&self.buffer)
6280    }
6281
6282    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6283    fn buffer_end_offset(&self) -> usize {
6284        self.buffer_start_offset() + self.text_summary.len
6285    }
6286}
6287
6288impl<'a> MultiBufferExcerpt<'a> {
6289    pub fn id(&self) -> ExcerptId {
6290        self.excerpt.id
6291    }
6292
6293    pub fn buffer_id(&self) -> BufferId {
6294        self.excerpt.buffer_id
6295    }
6296
6297    pub fn start_anchor(&self) -> Anchor {
6298        Anchor::in_buffer(
6299            self.excerpt.id,
6300            self.excerpt.buffer_id,
6301            self.excerpt.range.context.start,
6302        )
6303    }
6304
6305    pub fn end_anchor(&self) -> Anchor {
6306        Anchor::in_buffer(
6307            self.excerpt.id,
6308            self.excerpt.buffer_id,
6309            self.excerpt.range.context.end,
6310        )
6311    }
6312
6313    pub fn buffer(&self) -> &'a BufferSnapshot {
6314        &self.excerpt.buffer
6315    }
6316
6317    pub fn buffer_range(&self) -> Range<usize> {
6318        self.buffer_offset
6319            ..self
6320                .excerpt
6321                .range
6322                .context
6323                .end
6324                .to_offset(&self.excerpt.buffer.text)
6325    }
6326
6327    pub fn start_offset(&self) -> usize {
6328        self.offset
6329    }
6330
6331    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6332    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6333        self.map_range_to_buffer(offset..offset).start
6334    }
6335
6336    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6337    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6338        self.diff_transforms
6339            .seek(&OutputDimension(range.start), Bias::Right);
6340        let start = self.map_offset_to_buffer_internal(range.start);
6341        let end = if range.end > range.start {
6342            self.diff_transforms
6343                .seek_forward(&OutputDimension(range.end), Bias::Right);
6344            self.map_offset_to_buffer_internal(range.end)
6345        } else {
6346            start
6347        };
6348        start..end
6349    }
6350
6351    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6352        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
6353        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6354            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6355        };
6356        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6357        self.buffer_offset + offset_in_excerpt
6358    }
6359
6360    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6361    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6362        self.map_range_from_buffer(buffer_offset..buffer_offset)
6363            .start
6364    }
6365
6366    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6367    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6368        if buffer_range.start < self.buffer_offset {
6369            log::warn!(
6370                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6371            );
6372            return buffer_range;
6373        }
6374        let overshoot = buffer_range.start - self.buffer_offset;
6375        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6376        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
6377        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
6378            log::warn!(
6379                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6380            );
6381            return buffer_range;
6382        }
6383        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6384        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6385
6386        let end = if buffer_range.end > buffer_range.start {
6387            let overshoot = buffer_range.end - self.buffer_offset;
6388            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6389            self.diff_transforms
6390                .seek_forward(&excerpt_offset, Bias::Right);
6391            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6392            self.diff_transforms.start().output_dimension.0 + overshoot
6393        } else {
6394            start
6395        };
6396
6397        start..end
6398    }
6399
6400    /// Returns true if the entirety of the given range is in the buffer's excerpt
6401    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6402        range.start >= self.excerpt.buffer_start_offset()
6403            && range.end <= self.excerpt.buffer_end_offset()
6404    }
6405
6406    pub fn max_buffer_row(&self) -> u32 {
6407        self.excerpt.max_buffer_row
6408    }
6409}
6410
6411impl ExcerptId {
6412    pub fn min() -> Self {
6413        Self(0)
6414    }
6415
6416    pub fn max() -> Self {
6417        Self(u32::MAX)
6418    }
6419
6420    pub fn to_proto(self) -> u64 {
6421        self.0 as _
6422    }
6423
6424    pub fn from_proto(proto: u64) -> Self {
6425        Self(proto as _)
6426    }
6427
6428    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6429        let a = snapshot.excerpt_locator_for_id(*self);
6430        let b = snapshot.excerpt_locator_for_id(*other);
6431        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6432    }
6433}
6434
6435impl From<ExcerptId> for usize {
6436    fn from(val: ExcerptId) -> Self {
6437        val.0 as usize
6438    }
6439}
6440
6441impl fmt::Debug for Excerpt {
6442    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6443        f.debug_struct("Excerpt")
6444            .field("id", &self.id)
6445            .field("locator", &self.locator)
6446            .field("buffer_id", &self.buffer_id)
6447            .field("range", &self.range)
6448            .field("text_summary", &self.text_summary)
6449            .field("has_trailing_newline", &self.has_trailing_newline)
6450            .finish()
6451    }
6452}
6453
6454impl sum_tree::Item for Excerpt {
6455    type Summary = ExcerptSummary;
6456
6457    fn summary(&self, _cx: ()) -> Self::Summary {
6458        let mut text = self.text_summary;
6459        if self.has_trailing_newline {
6460            text += TextSummary::from("\n");
6461        }
6462        ExcerptSummary {
6463            excerpt_id: self.id,
6464            excerpt_locator: self.locator.clone(),
6465            widest_line_number: self.max_buffer_row,
6466            text,
6467        }
6468    }
6469}
6470
6471impl sum_tree::Item for ExcerptIdMapping {
6472    type Summary = ExcerptId;
6473
6474    fn summary(&self, _cx: ()) -> Self::Summary {
6475        self.id
6476    }
6477}
6478
6479impl sum_tree::KeyedItem for ExcerptIdMapping {
6480    type Key = ExcerptId;
6481
6482    fn key(&self) -> Self::Key {
6483        self.id
6484    }
6485}
6486
6487impl DiffTransform {
6488    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6489        match self {
6490            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6491            DiffTransform::BufferContent {
6492                inserted_hunk_info, ..
6493            } => *inserted_hunk_info,
6494        }
6495    }
6496}
6497
6498impl sum_tree::Item for DiffTransform {
6499    type Summary = DiffTransformSummary;
6500
6501    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6502        match self {
6503            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6504                input: *summary,
6505                output: *summary,
6506            },
6507            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6508                input: TextSummary::default(),
6509                output: *summary,
6510            },
6511        }
6512    }
6513}
6514
6515impl DiffTransformSummary {
6516    fn excerpt_len(&self) -> ExcerptOffset {
6517        ExcerptOffset::new(self.input.len)
6518    }
6519}
6520
6521impl sum_tree::ContextLessSummary for DiffTransformSummary {
6522    fn zero() -> Self {
6523        DiffTransformSummary {
6524            input: TextSummary::default(),
6525            output: TextSummary::default(),
6526        }
6527    }
6528
6529    fn add_summary(&mut self, other: &Self) {
6530        self.input += other.input;
6531        self.output += other.output;
6532    }
6533}
6534
6535impl sum_tree::ContextLessSummary for ExcerptId {
6536    fn zero() -> Self {
6537        Self(0)
6538    }
6539
6540    fn add_summary(&mut self, summary: &Self) {
6541        *self = cmp::max(*self, *summary);
6542    }
6543}
6544
6545impl sum_tree::ContextLessSummary for ExcerptSummary {
6546    fn zero() -> Self {
6547        Self::default()
6548    }
6549
6550    fn add_summary(&mut self, summary: &Self) {
6551        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6552        self.excerpt_locator = summary.excerpt_locator.clone();
6553        Summary::add_summary(&mut self.text, &summary.text, ());
6554        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6555    }
6556}
6557
6558impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6559    fn zero(_cx: ()) -> Self {
6560        Default::default()
6561    }
6562
6563    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6564        self.value += summary.text.len;
6565    }
6566}
6567
6568impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6569    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6570        Ord::cmp(&self.value, &cursor_location.text.len)
6571    }
6572}
6573
6574impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6575    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
6576        Ord::cmp(&Some(self), cursor_location)
6577    }
6578}
6579
6580impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6581    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6582        Ord::cmp(self, &cursor_location.excerpt_locator)
6583    }
6584}
6585
6586impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6587    fn zero(_cx: ()) -> Self {
6588        Default::default()
6589    }
6590
6591    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6592        self.value += summary.text.lines;
6593    }
6594}
6595
6596impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6597    for ExcerptDimension<D>
6598{
6599    fn zero(_: ()) -> Self {
6600        ExcerptDimension(D::default())
6601    }
6602
6603    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6604        self.0.add_assign(&D::from_text_summary(&summary.text))
6605    }
6606}
6607
6608impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6609    fn zero(_cx: ()) -> Self {
6610        Default::default()
6611    }
6612
6613    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6614        *self = Some(&summary.excerpt_locator);
6615    }
6616}
6617
6618impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6619    fn zero(_cx: ()) -> Self {
6620        Default::default()
6621    }
6622
6623    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6624        *self = Some(summary.excerpt_id);
6625    }
6626}
6627
6628#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6629struct ExcerptDimension<T>(T);
6630
6631#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6632struct OutputDimension<T>(T);
6633
6634impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6635    fn zero(_: ()) -> Self {
6636        ExcerptOffset::new(0)
6637    }
6638
6639    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6640        self.value += summary.input.len;
6641    }
6642}
6643
6644impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6645    fn zero(_: ()) -> Self {
6646        ExcerptPoint::new(0, 0)
6647    }
6648
6649    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6650        self.value += summary.input.lines;
6651    }
6652}
6653
6654impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6655    for ExcerptDimension<D>
6656{
6657    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
6658        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6659    }
6660}
6661
6662impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6663    for ExcerptDimension<D>
6664{
6665    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6666        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
6667    }
6668}
6669
6670impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6671    fn zero(_: ()) -> Self {
6672        ExcerptDimension(D::default())
6673    }
6674
6675    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6676        self.0.add_assign(&D::from_text_summary(&summary.input))
6677    }
6678}
6679
6680impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6681    for OutputDimension<D>
6682{
6683    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6684        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
6685    }
6686}
6687
6688impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6689    fn zero(_: ()) -> Self {
6690        OutputDimension(D::default())
6691    }
6692
6693    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6694        self.0.add_assign(&D::from_text_summary(&summary.output))
6695    }
6696}
6697
6698impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6699    fn zero(_: ()) -> Self {
6700        TextSummary::default()
6701    }
6702
6703    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6704        *self += summary.output
6705    }
6706}
6707
6708impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6709    fn zero(_: ()) -> Self {
6710        0
6711    }
6712
6713    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6714        *self += summary.output.len
6715    }
6716}
6717
6718impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6719    fn zero(_: ()) -> Self {
6720        Point::new(0, 0)
6721    }
6722
6723    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6724        *self += summary.output.lines
6725    }
6726}
6727
6728impl MultiBufferRows<'_> {
6729    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6730        self.point = Point::new(row, 0);
6731        self.cursor.seek(&self.point);
6732    }
6733}
6734
6735impl Iterator for MultiBufferRows<'_> {
6736    type Item = RowInfo;
6737
6738    fn next(&mut self) -> Option<Self::Item> {
6739        if self.is_empty && self.point.row == 0 {
6740            self.point += Point::new(1, 0);
6741            return Some(RowInfo {
6742                buffer_id: None,
6743                buffer_row: Some(0),
6744                multibuffer_row: Some(MultiBufferRow(0)),
6745                diff_status: None,
6746                expand_info: None,
6747            });
6748        }
6749
6750        let mut region = self.cursor.region()?;
6751        while self.point >= region.range.end {
6752            self.cursor.next();
6753            if let Some(next_region) = self.cursor.region() {
6754                region = next_region;
6755            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
6756                let multibuffer_row = MultiBufferRow(self.point.row);
6757                let last_excerpt = self
6758                    .cursor
6759                    .excerpts
6760                    .item()
6761                    .or(self.cursor.excerpts.prev_item())?;
6762                let last_row = last_excerpt
6763                    .range
6764                    .context
6765                    .end
6766                    .to_point(&last_excerpt.buffer)
6767                    .row;
6768
6769                let first_row = last_excerpt
6770                    .range
6771                    .context
6772                    .start
6773                    .to_point(&last_excerpt.buffer)
6774                    .row;
6775
6776                let expand_info = if self.is_singleton {
6777                    None
6778                } else {
6779                    let needs_expand_up = first_row == last_row
6780                        && last_row > 0
6781                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
6782                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
6783
6784                    if needs_expand_up && needs_expand_down {
6785                        Some(ExpandExcerptDirection::UpAndDown)
6786                    } else if needs_expand_up {
6787                        Some(ExpandExcerptDirection::Up)
6788                    } else if needs_expand_down {
6789                        Some(ExpandExcerptDirection::Down)
6790                    } else {
6791                        None
6792                    }
6793                    .map(|direction| ExpandInfo {
6794                        direction,
6795                        excerpt_id: last_excerpt.id,
6796                    })
6797                };
6798                self.point += Point::new(1, 0);
6799                return Some(RowInfo {
6800                    buffer_id: Some(last_excerpt.buffer_id),
6801                    buffer_row: Some(last_row),
6802                    multibuffer_row: Some(multibuffer_row),
6803                    diff_status: None,
6804                    expand_info,
6805                });
6806            } else {
6807                return None;
6808            };
6809        }
6810
6811        let overshoot = self.point - region.range.start;
6812        let buffer_point = region.buffer_range.start + overshoot;
6813        let expand_info = if self.is_singleton {
6814            None
6815        } else {
6816            let needs_expand_up = self.point.row == region.range.start.row
6817                && self.cursor.is_at_start_of_excerpt()
6818                && buffer_point.row > 0;
6819            let needs_expand_down = (region.excerpt.has_trailing_newline
6820                && self.point.row + 1 == region.range.end.row
6821                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
6822                && self.cursor.is_at_end_of_excerpt()
6823                && buffer_point.row < region.buffer.max_point().row;
6824
6825            if needs_expand_up && needs_expand_down {
6826                Some(ExpandExcerptDirection::UpAndDown)
6827            } else if needs_expand_up {
6828                Some(ExpandExcerptDirection::Up)
6829            } else if needs_expand_down {
6830                Some(ExpandExcerptDirection::Down)
6831            } else {
6832                None
6833            }
6834            .map(|direction| ExpandInfo {
6835                direction,
6836                excerpt_id: region.excerpt.id,
6837            })
6838        };
6839
6840        let result = Some(RowInfo {
6841            buffer_id: Some(region.buffer.remote_id()),
6842            buffer_row: Some(buffer_point.row),
6843            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6844            diff_status: region
6845                .diff_hunk_status
6846                .filter(|_| self.point < region.range.end),
6847            expand_info,
6848        });
6849        self.point += Point::new(1, 0);
6850        result
6851    }
6852}
6853
6854impl<'a> MultiBufferChunks<'a> {
6855    pub fn offset(&self) -> usize {
6856        self.range.start
6857    }
6858
6859    pub fn seek(&mut self, range: Range<usize>) {
6860        self.diff_transforms.seek(&range.end, Bias::Right);
6861        let mut excerpt_end = self.diff_transforms.start().1;
6862        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6863            let overshoot = range.end - self.diff_transforms.start().0;
6864            excerpt_end.value += overshoot;
6865        }
6866
6867        self.diff_transforms.seek(&range.start, Bias::Right);
6868        let mut excerpt_start = self.diff_transforms.start().1;
6869        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6870            let overshoot = range.start - self.diff_transforms.start().0;
6871            excerpt_start.value += overshoot;
6872        }
6873
6874        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6875        self.buffer_chunk.take();
6876        self.range = range;
6877    }
6878
6879    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6880        self.excerpt_offset_range = new_range.clone();
6881        self.excerpts.seek(&new_range.start, Bias::Right);
6882        if let Some(excerpt) = self.excerpts.item() {
6883            let excerpt_start = *self.excerpts.start();
6884            if let Some(excerpt_chunks) = self
6885                .excerpt_chunks
6886                .as_mut()
6887                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6888            {
6889                excerpt.seek_chunks(
6890                    excerpt_chunks,
6891                    (self.excerpt_offset_range.start - excerpt_start).value
6892                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6893                );
6894            } else {
6895                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6896                    (self.excerpt_offset_range.start - excerpt_start).value
6897                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6898                    self.language_aware,
6899                ));
6900            }
6901        } else {
6902            self.excerpt_chunks = None;
6903        }
6904    }
6905
6906    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6907        loop {
6908            if self.excerpt_offset_range.is_empty() {
6909                return None;
6910            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6911                self.excerpt_offset_range.start.value += chunk.text.len();
6912                return Some(chunk);
6913            } else {
6914                self.excerpts.next();
6915                let excerpt = self.excerpts.item()?;
6916                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6917                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6918                    self.language_aware,
6919                ));
6920            }
6921        }
6922    }
6923}
6924
6925impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6926    type Item = &'a str;
6927
6928    fn next(&mut self) -> Option<Self::Item> {
6929        let mut region = self.cursor.region()?;
6930        if self.offset == region.range.start {
6931            self.cursor.prev();
6932            region = self.cursor.region()?;
6933            let start_overshoot = self.start.saturating_sub(region.range.start);
6934            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6935                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6936            ));
6937        }
6938
6939        if self.offset == region.range.end && region.has_trailing_newline {
6940            self.offset -= 1;
6941            Some("\n")
6942        } else {
6943            let chunk = self.current_chunks.as_mut().unwrap().next()?;
6944            self.offset -= chunk.len();
6945            Some(chunk)
6946        }
6947    }
6948}
6949
6950impl<'a> Iterator for MultiBufferChunks<'a> {
6951    type Item = Chunk<'a>;
6952
6953    fn next(&mut self) -> Option<Chunk<'a>> {
6954        if self.range.start >= self.range.end {
6955            return None;
6956        }
6957        if self.range.start == self.diff_transforms.end().0 {
6958            self.diff_transforms.next();
6959        }
6960
6961        let diff_transform_start = self.diff_transforms.start().0;
6962        let diff_transform_end = self.diff_transforms.end().0;
6963        debug_assert!(self.range.start < diff_transform_end);
6964
6965        let diff_transform = self.diff_transforms.item()?;
6966        match diff_transform {
6967            DiffTransform::BufferContent { .. } => {
6968                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6969                    chunk
6970                } else {
6971                    let chunk = self.next_excerpt_chunk().unwrap();
6972                    self.buffer_chunk.insert(chunk)
6973                };
6974
6975                let chunk_end = self.range.start + chunk.text.len();
6976                let diff_transform_end = diff_transform_end.min(self.range.end);
6977
6978                if diff_transform_end < chunk_end {
6979                    let split_idx = diff_transform_end - self.range.start;
6980                    let (before, after) = chunk.text.split_at(split_idx);
6981                    self.range.start = diff_transform_end;
6982                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
6983                    let chars = chunk.chars & mask;
6984                    let tabs = chunk.tabs & mask;
6985
6986                    chunk.text = after;
6987                    chunk.chars = chunk.chars >> split_idx;
6988                    chunk.tabs = chunk.tabs >> split_idx;
6989
6990                    Some(Chunk {
6991                        text: before,
6992                        chars,
6993                        tabs,
6994                        ..chunk.clone()
6995                    })
6996                } else {
6997                    self.range.start = chunk_end;
6998                    self.buffer_chunk.take()
6999                }
7000            }
7001            DiffTransform::DeletedHunk {
7002                buffer_id,
7003                base_text_byte_range,
7004                has_trailing_newline,
7005                ..
7006            } => {
7007                let base_text_start =
7008                    base_text_byte_range.start + self.range.start - diff_transform_start;
7009                let base_text_end =
7010                    base_text_byte_range.start + self.range.end - diff_transform_start;
7011                let base_text_end = base_text_end.min(base_text_byte_range.end);
7012
7013                let mut chunks = if let Some((_, mut chunks)) = self
7014                    .diff_base_chunks
7015                    .take()
7016                    .filter(|(id, _)| id == buffer_id)
7017                {
7018                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7019                    {
7020                        chunks.seek(base_text_start..base_text_end);
7021                    }
7022                    chunks
7023                } else {
7024                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7025                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7026                };
7027
7028                let chunk = if let Some(chunk) = chunks.next() {
7029                    self.range.start += chunk.text.len();
7030                    self.diff_base_chunks = Some((*buffer_id, chunks));
7031                    chunk
7032                } else {
7033                    debug_assert!(has_trailing_newline);
7034                    self.range.start += "\n".len();
7035                    Chunk {
7036                        text: "\n",
7037                        chars: 1u128,
7038                        ..Default::default()
7039                    }
7040                };
7041                Some(chunk)
7042            }
7043        }
7044    }
7045}
7046
7047impl MultiBufferBytes<'_> {
7048    fn consume(&mut self, len: usize) {
7049        self.range.start += len;
7050        self.chunk = &self.chunk[len..];
7051
7052        if !self.range.is_empty() && self.chunk.is_empty() {
7053            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7054                self.chunk = chunk;
7055            } else if self.has_trailing_newline {
7056                self.has_trailing_newline = false;
7057                self.chunk = b"\n";
7058            } else {
7059                self.cursor.next();
7060                if let Some(region) = self.cursor.region() {
7061                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7062                        region.buffer_range.start
7063                            ..(region.buffer_range.start + self.range.end - region.range.start)
7064                                .min(region.buffer_range.end),
7065                    );
7066                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7067                    self.excerpt_bytes = Some(excerpt_bytes);
7068                    self.has_trailing_newline =
7069                        region.has_trailing_newline && self.range.end >= region.range.end;
7070                    if self.chunk.is_empty() && self.has_trailing_newline {
7071                        self.has_trailing_newline = false;
7072                        self.chunk = b"\n";
7073                    }
7074                }
7075            }
7076        }
7077    }
7078}
7079
7080impl<'a> Iterator for MultiBufferBytes<'a> {
7081    type Item = &'a [u8];
7082
7083    fn next(&mut self) -> Option<Self::Item> {
7084        let chunk = self.chunk;
7085        if chunk.is_empty() {
7086            None
7087        } else {
7088            self.consume(chunk.len());
7089            Some(chunk)
7090        }
7091    }
7092}
7093
7094impl io::Read for MultiBufferBytes<'_> {
7095    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7096        let len = cmp::min(buf.len(), self.chunk.len());
7097        buf[..len].copy_from_slice(&self.chunk[..len]);
7098        if len > 0 {
7099            self.consume(len);
7100        }
7101        Ok(len)
7102    }
7103}
7104
7105impl io::Read for ReversedMultiBufferBytes<'_> {
7106    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7107        let len = cmp::min(buf.len(), self.chunk.len());
7108        buf[..len].copy_from_slice(&self.chunk[..len]);
7109        buf[..len].reverse();
7110        if len > 0 {
7111            self.range.end -= len;
7112            self.chunk = &self.chunk[..self.chunk.len() - len];
7113            if !self.range.is_empty()
7114                && self.chunk.is_empty()
7115                && let Some(chunk) = self.chunks.next()
7116            {
7117                self.chunk = chunk.as_bytes();
7118            }
7119        }
7120        Ok(len)
7121    }
7122}
7123
7124impl<'a> Iterator for ExcerptChunks<'a> {
7125    type Item = Chunk<'a>;
7126
7127    fn next(&mut self) -> Option<Self::Item> {
7128        if let Some(chunk) = self.content_chunks.next() {
7129            return Some(chunk);
7130        }
7131
7132        if self.has_footer {
7133            let text = "\n";
7134            let chars = 0b1;
7135            self.has_footer = false;
7136            return Some(Chunk {
7137                text,
7138                chars,
7139                ..Default::default()
7140            });
7141        }
7142
7143        None
7144    }
7145}
7146
7147impl ToOffset for Point {
7148    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7149        snapshot.point_to_offset(*self)
7150    }
7151    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7152        snapshot.point_to_offset_utf16(*self)
7153    }
7154}
7155
7156impl ToOffset for usize {
7157    #[track_caller]
7158    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7159        assert!(
7160            *self <= snapshot.len(),
7161            "offset {} is greater than the snapshot.len() {}",
7162            *self,
7163            snapshot.len(),
7164        );
7165        *self
7166    }
7167    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7168        snapshot.offset_to_offset_utf16(*self)
7169    }
7170}
7171
7172impl ToOffset for OffsetUtf16 {
7173    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7174        snapshot.offset_utf16_to_offset(*self)
7175    }
7176
7177    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7178        *self
7179    }
7180}
7181
7182impl ToOffset for PointUtf16 {
7183    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7184        snapshot.point_utf16_to_offset(*self)
7185    }
7186    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7187        snapshot.point_utf16_to_offset_utf16(*self)
7188    }
7189}
7190
7191impl ToPoint for usize {
7192    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7193        snapshot.offset_to_point(*self)
7194    }
7195    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7196        snapshot.offset_to_point_utf16(*self)
7197    }
7198}
7199
7200impl ToPoint for Point {
7201    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7202        *self
7203    }
7204    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7205        snapshot.point_to_point_utf16(*self)
7206    }
7207}
7208
7209impl ToPoint for PointUtf16 {
7210    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7211        snapshot.point_utf16_to_point(*self)
7212    }
7213    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7214        *self
7215    }
7216}
7217
7218impl From<ExcerptId> for EntityId {
7219    fn from(id: ExcerptId) -> Self {
7220        EntityId::from(id.0 as u64)
7221    }
7222}
7223
7224#[cfg(debug_assertions)]
7225pub mod debug {
7226    use super::*;
7227
7228    pub trait ToMultiBufferDebugRanges {
7229        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7230        -> Vec<Range<usize>>;
7231    }
7232
7233    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7234        fn to_multi_buffer_debug_ranges(
7235            &self,
7236            snapshot: &MultiBufferSnapshot,
7237        ) -> Vec<Range<usize>> {
7238            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7239        }
7240    }
7241
7242    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7243        fn to_multi_buffer_debug_ranges(
7244            &self,
7245            snapshot: &MultiBufferSnapshot,
7246        ) -> Vec<Range<usize>> {
7247            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7248                .to_multi_buffer_debug_ranges(snapshot)
7249        }
7250    }
7251
7252    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7253        fn to_multi_buffer_debug_ranges(
7254            &self,
7255            snapshot: &MultiBufferSnapshot,
7256        ) -> Vec<Range<usize>> {
7257            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7258        }
7259    }
7260
7261    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7262        fn to_multi_buffer_debug_ranges(
7263            &self,
7264            snapshot: &MultiBufferSnapshot,
7265        ) -> Vec<Range<usize>> {
7266            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7267        }
7268    }
7269
7270    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7271        fn to_multi_buffer_debug_ranges(
7272            &self,
7273            snapshot: &MultiBufferSnapshot,
7274        ) -> Vec<Range<usize>> {
7275            self.iter()
7276                .map(|item| {
7277                    let offset = item.to_offset(snapshot);
7278                    offset..offset
7279                })
7280                .collect()
7281        }
7282    }
7283
7284    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7285        fn to_multi_buffer_debug_ranges(
7286            &self,
7287            snapshot: &MultiBufferSnapshot,
7288        ) -> Vec<Range<usize>> {
7289            self.iter()
7290                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7291                .collect()
7292        }
7293    }
7294}
7295
7296// FIXME figure out whether this should have a different API or something
7297#[cfg(feature = "test-support")]
7298pub fn randomly_mutate_multibuffer_with_diffs(
7299    multibuffer: Entity<MultiBuffer>,
7300    buffers: &mut Vec<Entity<Buffer>>,
7301    base_texts: &mut HashMap<BufferId, String>,
7302    needs_diff_calculation: &mut bool,
7303    rng: &mut rand::rngs::StdRng,
7304    cx: &mut gpui::TestAppContext,
7305) {
7306    use rand::Rng as _;
7307    use rand::seq::IndexedRandom as _;
7308
7309    fn format_diff(
7310        text: &str,
7311        row_infos: &Vec<RowInfo>,
7312        boundary_rows: &HashSet<MultiBufferRow>,
7313        has_diff: Option<bool>,
7314    ) -> String {
7315        let has_diff =
7316            has_diff.unwrap_or_else(|| row_infos.iter().any(|info| info.diff_status.is_some()));
7317        let mut running_total = 0;
7318        text.split('\n')
7319            .enumerate()
7320            .zip(row_infos)
7321            .map(|((ix, line), info)| {
7322                let running_total_before = running_total;
7323                let line_length = line.len();
7324                running_total += line_length;
7325                let running_total_after = running_total;
7326                running_total += 1;
7327                let marker = match info.diff_status.map(|status| status.kind) {
7328                    Some(DiffHunkStatusKind::Added) => "+ ",
7329                    Some(DiffHunkStatusKind::Deleted) => "- ",
7330                    Some(DiffHunkStatusKind::Modified) => unreachable!(),
7331                    None => {
7332                        if has_diff && !line.is_empty() {
7333                            "  "
7334                        } else {
7335                            ""
7336                        }
7337                    }
7338                };
7339                // format: 123->124 (len: 001)
7340                let line_numbers = format!(
7341                    "{running_total_before:0>3}->{running_total_after:0>3} (len: {line_length:0>3})"
7342                );
7343                if boundary_rows.contains(&MultiBufferRow(ix as u32)) {
7344                    let boundary_row = if has_diff {
7345                        "                   |  ----------\n"
7346                    } else {
7347                        "                   |----------\n"
7348                    };
7349                    format!("{boundary_row}{line_numbers}|{marker}{line}")
7350                } else {
7351                    format!("{line_numbers}|{marker}{line}")
7352                }
7353            })
7354            .collect::<Vec<_>>()
7355            .join("\n")
7356    }
7357
7358    let excerpt_ids = multibuffer.read_with(cx, |multibuffer, _| multibuffer.excerpt_ids());
7359    // TODO cover changes of base text?
7360    match rng.random_range(0..100) {
7361        0..=49 if !buffers.is_empty() => {
7362            let buffer = buffers.choose(rng).unwrap();
7363            buffer.update(cx, |buf, cx| {
7364                let edit_count = rng.random_range(1..5);
7365                log::info!("editing buffer");
7366                buf.randomly_edit(rng, edit_count, cx);
7367                *needs_diff_calculation = true;
7368            });
7369        }
7370        50..=69 if *needs_diff_calculation => {
7371            multibuffer.update(cx, |multibuffer, cx| {
7372                for buffer in buffers {
7373                    use util::rel_path::rel_path;
7374
7375                    let snapshot = buffer.read(cx).snapshot();
7376                    let diff = multibuffer.diff_for(snapshot.remote_id()).unwrap();
7377                    diff.update(cx, |diff, cx| {
7378                        log::info!("recalculating diff for buffer {:?}", snapshot.remote_id());
7379                        diff.recalculate_diff_sync(snapshot.text.clone(), cx);
7380                    });
7381
7382                    let ranges = diff
7383                        .read(cx)
7384                        .hunks(&snapshot, cx)
7385                        .map(|hunk| hunk.buffer_range.to_point(&snapshot))
7386                        .collect::<Vec<_>>();
7387
7388                    multibuffer.set_excerpts_for_path(
7389                        PathKey {
7390                            sort_prefix: None,
7391                            path: rel_path(&buffer.read(cx).remote_id().to_string()).into_arc(),
7392                        },
7393                        buffer.clone(),
7394                        ranges.into_iter(),
7395                        2,
7396                        cx,
7397                    );
7398                }
7399                *needs_diff_calculation = false;
7400            });
7401        }
7402        70..=79 if !excerpt_ids.is_empty() => {
7403            multibuffer.update(cx, |multibuffer, cx| {
7404                let ids = multibuffer.excerpt_ids();
7405                let mut excerpts = HashSet::default();
7406                for _ in 0..rng.random_range(0..ids.len()) {
7407                    excerpts.extend(ids.choose(rng).copied());
7408                }
7409
7410                let line_count = rng.random_range(0..5);
7411
7412                log::info!("Expanding excerpts by {line_count} lines");
7413                multibuffer.expand_excerpts(
7414                    excerpts.iter().cloned(),
7415                    line_count,
7416                    ExpandExcerptDirection::UpAndDown,
7417                    cx,
7418                );
7419            });
7420        }
7421        _ => {
7422            let mut base_text = util::RandomCharIter::new(&mut *rng)
7423                .take(256)
7424                .collect::<String>();
7425
7426            let buffer = cx.new(|cx| Buffer::local(base_text.clone(), cx));
7427            text::LineEnding::normalize(&mut base_text);
7428            base_texts.insert(
7429                buffer.read_with(cx, |buffer, _| buffer.remote_id()),
7430                base_text,
7431            );
7432            buffers.push(buffer);
7433            let buffer_handle = buffers.last().unwrap();
7434
7435            multibuffer.update(cx, |multibuffer, cx| {
7436                let id = buffer_handle.read(cx).remote_id();
7437                if multibuffer.diff_for(id).is_none() {
7438                    let base_text = base_texts.get(&id).unwrap();
7439                    let diff =
7440                        cx.new(|cx| BufferDiff::new_with_base_text(base_text, buffer_handle, cx));
7441                    multibuffer.add_diff(diff, cx)
7442                }
7443            });
7444
7445            *needs_diff_calculation = true;
7446        }
7447    }
7448
7449    {
7450        let snapshot = multibuffer.read_with(cx, |multibuffer, cx| multibuffer.snapshot(cx));
7451        let actual_boundary_rows = snapshot
7452            .excerpt_boundaries_in_range(0..)
7453            .map(|b| b.row)
7454            .collect::<HashSet<_>>();
7455        log::info!(
7456            "multibuffer contents:\n{}",
7457            format_diff(
7458                &snapshot.text(),
7459                &snapshot.row_infos(MultiBufferRow(0)).collect(),
7460                &actual_boundary_rows,
7461                Some(true)
7462            )
7463        );
7464    }
7465}