buffer_view.rs

   1use super::{
   2    buffer, movement, Anchor, Bias, Buffer, BufferElement, DisplayMap, DisplayPoint, Point,
   3    Selection, SelectionSetId, ToOffset, ToPoint,
   4};
   5use crate::{settings::Settings, watch, workspace, worktree::FileHandle};
   6use anyhow::Result;
   7use futures_core::future::LocalBoxFuture;
   8use gpui::{
   9    fonts::Properties as FontProperties, keymap::Binding, text_layout, AppContext, ClipboardItem,
  10    Element, ElementBox, Entity, FontCache, ModelHandle, MutableAppContext, View, ViewContext,
  11    WeakViewHandle,
  12};
  13use gpui::{geometry::vector::Vector2F, TextLayoutCache};
  14use parking_lot::Mutex;
  15use serde::{Deserialize, Serialize};
  16use smallvec::SmallVec;
  17use smol::Timer;
  18use std::{
  19    cmp::{self, Ordering},
  20    fmt::Write,
  21    iter::FromIterator,
  22    ops::Range,
  23    path::Path,
  24    sync::Arc,
  25    time::Duration,
  26};
  27
  28const CURSOR_BLINK_INTERVAL: Duration = Duration::from_millis(500);
  29
  30pub fn init(app: &mut MutableAppContext) {
  31    app.add_bindings(vec![
  32        Binding::new("backspace", "buffer:backspace", Some("BufferView")),
  33        Binding::new("enter", "buffer:newline", Some("BufferView")),
  34        Binding::new("cmd-x", "buffer:cut", Some("BufferView")),
  35        Binding::new("cmd-c", "buffer:copy", Some("BufferView")),
  36        Binding::new("cmd-v", "buffer:paste", Some("BufferView")),
  37        Binding::new("cmd-z", "buffer:undo", Some("BufferView")),
  38        Binding::new("cmd-shift-Z", "buffer:redo", Some("BufferView")),
  39        Binding::new("up", "buffer:move_up", Some("BufferView")),
  40        Binding::new("down", "buffer:move_down", Some("BufferView")),
  41        Binding::new("left", "buffer:move_left", Some("BufferView")),
  42        Binding::new("right", "buffer:move_right", Some("BufferView")),
  43        Binding::new("shift-up", "buffer:select_up", Some("BufferView")),
  44        Binding::new("shift-down", "buffer:select_down", Some("BufferView")),
  45        Binding::new("shift-left", "buffer:select_left", Some("BufferView")),
  46        Binding::new("shift-right", "buffer:select_right", Some("BufferView")),
  47        Binding::new("pageup", "buffer:page_up", Some("BufferView")),
  48        Binding::new("pagedown", "buffer:page_down", Some("BufferView")),
  49        Binding::new("alt-cmd-[", "buffer:fold", Some("BufferView")),
  50        Binding::new("alt-cmd-]", "buffer:unfold", Some("BufferView")),
  51        Binding::new(
  52            "alt-cmd-f",
  53            "buffer:fold_selected_ranges",
  54            Some("BufferView"),
  55        ),
  56    ]);
  57
  58    app.add_action("buffer:scroll", BufferView::scroll);
  59    app.add_action("buffer:select", BufferView::select);
  60    app.add_action("buffer:insert", BufferView::insert);
  61    app.add_action("buffer:newline", BufferView::newline);
  62    app.add_action("buffer:backspace", BufferView::backspace);
  63    app.add_action("buffer:cut", BufferView::cut);
  64    app.add_action("buffer:copy", BufferView::copy);
  65    app.add_action("buffer:paste", BufferView::paste);
  66    app.add_action("buffer:undo", BufferView::undo);
  67    app.add_action("buffer:redo", BufferView::redo);
  68    app.add_action("buffer:move_up", BufferView::move_up);
  69    app.add_action("buffer:move_down", BufferView::move_down);
  70    app.add_action("buffer:move_left", BufferView::move_left);
  71    app.add_action("buffer:move_right", BufferView::move_right);
  72    app.add_action("buffer:select_up", BufferView::select_up);
  73    app.add_action("buffer:select_down", BufferView::select_down);
  74    app.add_action("buffer:select_left", BufferView::select_left);
  75    app.add_action("buffer:select_right", BufferView::select_right);
  76    app.add_action("buffer:page_up", BufferView::page_up);
  77    app.add_action("buffer:page_down", BufferView::page_down);
  78    app.add_action("buffer:fold", BufferView::fold);
  79    app.add_action("buffer:unfold", BufferView::unfold);
  80    app.add_action(
  81        "buffer:fold_selected_ranges",
  82        BufferView::fold_selected_ranges,
  83    );
  84}
  85
  86pub enum SelectAction {
  87    Begin {
  88        position: DisplayPoint,
  89        add: bool,
  90    },
  91    Update {
  92        position: DisplayPoint,
  93        scroll_position: Vector2F,
  94    },
  95    End,
  96}
  97
  98pub struct BufferView {
  99    handle: WeakViewHandle<Self>,
 100    buffer: ModelHandle<Buffer>,
 101    file: Option<FileHandle>,
 102    display_map: ModelHandle<DisplayMap>,
 103    selection_set_id: SelectionSetId,
 104    pending_selection: Option<Selection>,
 105    scroll_position: Mutex<Vector2F>,
 106    autoscroll_requested: Mutex<bool>,
 107    settings: watch::Receiver<Settings>,
 108    focused: bool,
 109    cursors_visible: bool,
 110    blink_epoch: usize,
 111    blinking_paused: bool,
 112    single_line: bool,
 113}
 114
 115#[derive(Serialize, Deserialize)]
 116struct ClipboardSelection {
 117    len: usize,
 118    is_entire_line: bool,
 119}
 120
 121impl BufferView {
 122    pub fn single_line(settings: watch::Receiver<Settings>, ctx: &mut ViewContext<Self>) -> Self {
 123        let buffer = ctx.add_model(|_| Buffer::new(0, String::new()));
 124        let mut view = Self::for_buffer(buffer, None, settings, ctx);
 125        view.single_line = true;
 126        view
 127    }
 128
 129    pub fn for_buffer(
 130        buffer: ModelHandle<Buffer>,
 131        file: Option<FileHandle>,
 132        settings: watch::Receiver<Settings>,
 133        ctx: &mut ViewContext<Self>,
 134    ) -> Self {
 135        settings.notify_view_on_change(ctx);
 136
 137        if let Some(file) = file.as_ref() {
 138            file.observe_from_view(ctx, |_, _, ctx| ctx.emit(Event::FileHandleChanged));
 139        }
 140
 141        ctx.observe(&buffer, Self::on_buffer_changed);
 142        ctx.subscribe_to_model(&buffer, Self::on_buffer_event);
 143        let display_map = ctx.add_model(|ctx| {
 144            DisplayMap::new(
 145                buffer.clone(),
 146                smol::block_on(settings.read()).tab_size,
 147                ctx,
 148            )
 149        });
 150        ctx.observe(&display_map, Self::on_display_map_changed);
 151
 152        let (selection_set_id, _) = buffer.update(ctx, |buffer, ctx| {
 153            buffer.add_selection_set(
 154                vec![Selection {
 155                    start: buffer.anchor_before(0).unwrap(),
 156                    end: buffer.anchor_before(0).unwrap(),
 157                    reversed: false,
 158                    goal_column: None,
 159                }],
 160                Some(ctx),
 161            )
 162        });
 163        Self {
 164            handle: ctx.handle().downgrade(),
 165            buffer,
 166            file,
 167            display_map,
 168            selection_set_id,
 169            pending_selection: None,
 170            scroll_position: Mutex::new(Vector2F::zero()),
 171            autoscroll_requested: Mutex::new(false),
 172            settings,
 173            focused: false,
 174            cursors_visible: false,
 175            blink_epoch: 0,
 176            blinking_paused: false,
 177            single_line: false,
 178        }
 179    }
 180
 181    pub fn buffer(&self) -> &ModelHandle<Buffer> {
 182        &self.buffer
 183    }
 184
 185    pub fn is_gutter_visible(&self) -> bool {
 186        !self.single_line
 187    }
 188
 189    fn scroll(&mut self, scroll_position: &Vector2F, ctx: &mut ViewContext<Self>) {
 190        *self.scroll_position.lock() = *scroll_position;
 191        ctx.notify();
 192    }
 193
 194    pub fn scroll_position(&self) -> Vector2F {
 195        *self.scroll_position.lock()
 196    }
 197
 198    pub fn clamp_scroll_left(&self, max: f32) {
 199        let mut scroll_position = self.scroll_position.lock();
 200        let scroll_left = scroll_position.x();
 201        scroll_position.set_x(scroll_left.min(max));
 202    }
 203
 204    pub fn autoscroll_vertically(
 205        &self,
 206        viewport_height: f32,
 207        line_height: f32,
 208        app: &AppContext,
 209    ) -> bool {
 210        let mut scroll_position = self.scroll_position.lock();
 211        let scroll_top = scroll_position.y();
 212        scroll_position.set_y(scroll_top.min(self.max_point(app).row().saturating_sub(1) as f32));
 213
 214        let mut autoscroll_requested = self.autoscroll_requested.lock();
 215        if *autoscroll_requested {
 216            *autoscroll_requested = false;
 217        } else {
 218            return false;
 219        }
 220
 221        let map = self.display_map.read(app);
 222        let visible_lines = viewport_height / line_height;
 223        let first_cursor_top = self
 224            .selections(app)
 225            .first()
 226            .unwrap()
 227            .head()
 228            .to_display_point(map, app)
 229            .unwrap()
 230            .row() as f32;
 231        let last_cursor_bottom = self
 232            .selections(app)
 233            .last()
 234            .unwrap()
 235            .head()
 236            .to_display_point(map, app)
 237            .unwrap()
 238            .row() as f32
 239            + 1.0;
 240
 241        let margin = ((visible_lines - (last_cursor_bottom - first_cursor_top)) / 2.0)
 242            .floor()
 243            .min(3.0);
 244        if margin < 0.0 {
 245            return false;
 246        }
 247
 248        let target_top = (first_cursor_top - margin).max(0.0);
 249        let target_bottom = last_cursor_bottom + margin;
 250        let start_row = scroll_position.y();
 251        let end_row = start_row + visible_lines;
 252
 253        if target_top < start_row {
 254            scroll_position.set_y(target_top);
 255        } else if target_bottom >= end_row {
 256            scroll_position.set_y(target_bottom - visible_lines);
 257        }
 258
 259        true
 260    }
 261
 262    pub fn autoscroll_horizontally(
 263        &self,
 264        start_row: u32,
 265        viewport_width: f32,
 266        scroll_width: f32,
 267        max_glyph_width: f32,
 268        layouts: &[Arc<text_layout::Line>],
 269        app: &AppContext,
 270    ) {
 271        let map = self.display_map.read(app);
 272
 273        let mut target_left = std::f32::INFINITY;
 274        let mut target_right = 0.0_f32;
 275        for selection in self.selections(app) {
 276            let head = selection.head().to_display_point(map, app).unwrap();
 277            let start_column = head.column().saturating_sub(3);
 278            let end_column = cmp::min(map.line_len(head.row(), app).unwrap(), head.column() + 3);
 279            target_left = target_left
 280                .min(layouts[(head.row() - start_row) as usize].x_for_index(start_column as usize));
 281            target_right = target_right.max(
 282                layouts[(head.row() - start_row) as usize].x_for_index(end_column as usize)
 283                    + max_glyph_width,
 284            );
 285        }
 286        target_right = target_right.min(scroll_width);
 287
 288        if target_right - target_left > viewport_width {
 289            return;
 290        }
 291
 292        let mut scroll_position = self.scroll_position.lock();
 293        let scroll_left = scroll_position.x() * max_glyph_width;
 294        let scroll_right = scroll_left + viewport_width;
 295
 296        if target_left < scroll_left {
 297            scroll_position.set_x(target_left / max_glyph_width);
 298        } else if target_right > scroll_right {
 299            scroll_position.set_x((target_right - viewport_width) / max_glyph_width);
 300        }
 301    }
 302
 303    fn select(&mut self, arg: &SelectAction, ctx: &mut ViewContext<Self>) {
 304        match arg {
 305            SelectAction::Begin { position, add } => self.begin_selection(*position, *add, ctx),
 306            SelectAction::Update {
 307                position,
 308                scroll_position,
 309            } => self.update_selection(*position, *scroll_position, ctx),
 310            SelectAction::End => self.end_selection(ctx),
 311        }
 312    }
 313
 314    fn begin_selection(&mut self, position: DisplayPoint, add: bool, ctx: &mut ViewContext<Self>) {
 315        if !self.focused {
 316            ctx.focus_self();
 317            ctx.emit(Event::Activate);
 318        }
 319
 320        let display_map = self.display_map.read(ctx);
 321        let cursor = display_map
 322            .anchor_before(position, Bias::Left, ctx.as_ref())
 323            .unwrap();
 324        let selection = Selection {
 325            start: cursor.clone(),
 326            end: cursor,
 327            reversed: false,
 328            goal_column: None,
 329        };
 330
 331        if !add {
 332            self.update_selections(Vec::new(), false, ctx);
 333        }
 334        self.pending_selection = Some(selection);
 335
 336        ctx.notify();
 337    }
 338
 339    fn update_selection(
 340        &mut self,
 341        position: DisplayPoint,
 342        scroll_position: Vector2F,
 343        ctx: &mut ViewContext<Self>,
 344    ) {
 345        let buffer = self.buffer.read(ctx);
 346        let map = self.display_map.read(ctx);
 347        let cursor = map
 348            .anchor_before(position, Bias::Left, ctx.as_ref())
 349            .unwrap();
 350        if let Some(selection) = self.pending_selection.as_mut() {
 351            selection.set_head(buffer, cursor);
 352        } else {
 353            log::error!("update_selection dispatched with no pending selection");
 354            return;
 355        }
 356
 357        *self.scroll_position.lock() = scroll_position;
 358
 359        ctx.notify();
 360    }
 361
 362    fn end_selection(&mut self, ctx: &mut ViewContext<Self>) {
 363        if let Some(selection) = self.pending_selection.take() {
 364            let ix = self.selection_insertion_index(&selection.start, ctx.as_ref());
 365            let mut selections = self.selections(ctx.as_ref()).to_vec();
 366            selections.insert(ix, selection);
 367            self.update_selections(selections, false, ctx);
 368        } else {
 369            log::error!("end_selection dispatched with no pending selection");
 370        }
 371    }
 372
 373    pub fn is_selecting(&self) -> bool {
 374        self.pending_selection.is_some()
 375    }
 376
 377    #[cfg(test)]
 378    fn select_ranges<'a, T>(&mut self, ranges: T, ctx: &mut ViewContext<Self>) -> Result<()>
 379    where
 380        T: IntoIterator<Item = &'a Range<usize>>,
 381    {
 382        let buffer = self.buffer.read(ctx);
 383        let mut selections = Vec::new();
 384        for range in ranges {
 385            selections.push(Selection {
 386                start: buffer.anchor_before(range.start)?,
 387                end: buffer.anchor_before(range.end)?,
 388                reversed: false,
 389                goal_column: None,
 390            });
 391        }
 392        self.update_selections(selections, false, ctx);
 393        Ok(())
 394    }
 395
 396    #[cfg(test)]
 397    fn select_display_ranges<'a, T>(&mut self, ranges: T, ctx: &mut ViewContext<Self>) -> Result<()>
 398    where
 399        T: IntoIterator<Item = &'a Range<DisplayPoint>>,
 400    {
 401        let map = self.display_map.read(ctx);
 402        let mut selections = Vec::new();
 403        for range in ranges {
 404            selections.push(Selection {
 405                start: map.anchor_before(range.start, Bias::Left, ctx.as_ref())?,
 406                end: map.anchor_before(range.end, Bias::Left, ctx.as_ref())?,
 407                reversed: false,
 408                goal_column: None,
 409            });
 410        }
 411        self.update_selections(selections, false, ctx);
 412        Ok(())
 413    }
 414
 415    pub fn insert(&mut self, text: &String, ctx: &mut ViewContext<Self>) {
 416        let mut offset_ranges = SmallVec::<[Range<usize>; 32]>::new();
 417        {
 418            let buffer = self.buffer.read(ctx);
 419            for selection in self.selections(ctx.as_ref()) {
 420                let start = selection.start.to_offset(buffer).unwrap();
 421                let end = selection.end.to_offset(buffer).unwrap();
 422                offset_ranges.push(start..end);
 423            }
 424        }
 425
 426        self.start_transaction(ctx);
 427        let mut new_selections = Vec::new();
 428        self.buffer.update(ctx, |buffer, ctx| {
 429            if let Err(error) = buffer.edit(offset_ranges.iter().cloned(), text.as_str(), Some(ctx))
 430            {
 431                log::error!("error inserting text: {}", error);
 432            };
 433            let char_count = text.chars().count() as isize;
 434            let mut delta = 0_isize;
 435            new_selections = offset_ranges
 436                .into_iter()
 437                .map(|range| {
 438                    let start = range.start as isize;
 439                    let end = range.end as isize;
 440                    let anchor = buffer
 441                        .anchor_before((start + delta + char_count) as usize)
 442                        .unwrap();
 443                    let deleted_count = end - start;
 444                    delta += char_count - deleted_count;
 445                    Selection {
 446                        start: anchor.clone(),
 447                        end: anchor,
 448                        reversed: false,
 449                        goal_column: None,
 450                    }
 451                })
 452                .collect();
 453        });
 454
 455        self.update_selections(new_selections, true, ctx);
 456        self.end_transaction(ctx);
 457    }
 458
 459    fn newline(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 460        if self.single_line {
 461            ctx.propagate_action();
 462        } else {
 463            self.insert(&"\n".into(), ctx);
 464        }
 465    }
 466
 467    pub fn backspace(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 468        self.start_transaction(ctx);
 469        let mut selections = self.selections(ctx.as_ref()).to_vec();
 470        {
 471            let buffer = self.buffer.read(ctx);
 472            let map = self.display_map.read(ctx);
 473            for selection in &mut selections {
 474                if selection.range(buffer).is_empty() {
 475                    let head = selection
 476                        .head()
 477                        .to_display_point(map, ctx.as_ref())
 478                        .unwrap();
 479                    let cursor = map
 480                        .anchor_before(
 481                            movement::left(map, head, ctx.as_ref()).unwrap(),
 482                            Bias::Left,
 483                            ctx.as_ref(),
 484                        )
 485                        .unwrap();
 486                    selection.set_head(&buffer, cursor);
 487                    selection.goal_column = None;
 488                }
 489            }
 490        }
 491
 492        self.update_selections(selections, true, ctx);
 493        self.insert(&String::new(), ctx);
 494        self.end_transaction(ctx);
 495    }
 496
 497    pub fn cut(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 498        self.start_transaction(ctx);
 499        let mut text = String::new();
 500        let mut selections = self.selections(ctx.as_ref()).to_vec();
 501        let mut clipboard_selections = Vec::with_capacity(selections.len());
 502        {
 503            let buffer = self.buffer.read(ctx);
 504            let max_point = buffer.max_point();
 505            for selection in &mut selections {
 506                let mut start = selection.start.to_point(buffer).expect("invalid start");
 507                let mut end = selection.end.to_point(buffer).expect("invalid end");
 508                let is_entire_line = start == end;
 509                if is_entire_line {
 510                    start = Point::new(start.row, 0);
 511                    end = cmp::min(max_point, Point::new(start.row + 1, 0));
 512                    selection.start = buffer.anchor_before(start).unwrap();
 513                    selection.end = buffer.anchor_before(end).unwrap();
 514                }
 515                let mut len = 0;
 516                for ch in buffer.text_for_range(start..end).unwrap() {
 517                    text.push(ch);
 518                    len += 1;
 519                }
 520                clipboard_selections.push(ClipboardSelection {
 521                    len,
 522                    is_entire_line,
 523                });
 524            }
 525        }
 526        self.update_selections(selections, true, ctx);
 527        self.insert(&String::new(), ctx);
 528        self.end_transaction(ctx);
 529
 530        ctx.as_mut()
 531            .write_to_clipboard(ClipboardItem::new(text).with_metadata(clipboard_selections));
 532    }
 533
 534    pub fn copy(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 535        let buffer = self.buffer.read(ctx);
 536        let max_point = buffer.max_point();
 537        let mut text = String::new();
 538        let selections = self.selections(ctx.as_ref());
 539        let mut clipboard_selections = Vec::with_capacity(selections.len());
 540        for selection in selections {
 541            let mut start = selection.start.to_point(buffer).expect("invalid start");
 542            let mut end = selection.end.to_point(buffer).expect("invalid end");
 543            let is_entire_line = start == end;
 544            if is_entire_line {
 545                start = Point::new(start.row, 0);
 546                end = cmp::min(max_point, Point::new(start.row + 1, 0));
 547            }
 548            let mut len = 0;
 549            for ch in buffer.text_for_range(start..end).unwrap() {
 550                text.push(ch);
 551                len += 1;
 552            }
 553            clipboard_selections.push(ClipboardSelection {
 554                len,
 555                is_entire_line,
 556            });
 557        }
 558
 559        ctx.as_mut()
 560            .write_to_clipboard(ClipboardItem::new(text).with_metadata(clipboard_selections));
 561    }
 562
 563    pub fn paste(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 564        if let Some(item) = ctx.as_mut().read_from_clipboard() {
 565            let clipboard_text = item.text();
 566            if let Some(mut clipboard_selections) = item.metadata::<Vec<ClipboardSelection>>() {
 567                let selections = self.selections(ctx.as_ref()).to_vec();
 568                if clipboard_selections.len() != selections.len() {
 569                    let merged_selection = ClipboardSelection {
 570                        len: clipboard_selections.iter().map(|s| s.len).sum(),
 571                        is_entire_line: clipboard_selections.iter().all(|s| s.is_entire_line),
 572                    };
 573                    clipboard_selections.clear();
 574                    clipboard_selections.push(merged_selection);
 575                }
 576
 577                self.start_transaction(ctx);
 578                let mut new_selections = Vec::with_capacity(selections.len());
 579                let mut clipboard_chars = clipboard_text.chars().cycle();
 580                for (selection, clipboard_selection) in
 581                    selections.iter().zip(clipboard_selections.iter().cycle())
 582                {
 583                    let to_insert =
 584                        String::from_iter(clipboard_chars.by_ref().take(clipboard_selection.len));
 585
 586                    self.buffer.update(ctx, |buffer, ctx| {
 587                        let selection_start = selection.start.to_point(buffer).unwrap();
 588                        let selection_end = selection.end.to_point(buffer).unwrap();
 589
 590                        // If the corresponding selection was empty when this slice of the
 591                        // clipboard text was written, then the entire line containing the
 592                        // selection was copied. If this selection is also currently empty,
 593                        // then paste the line before the current line of the buffer.
 594                        let new_selection_start = selection.end.bias_right(buffer).unwrap();
 595                        if selection_start == selection_end && clipboard_selection.is_entire_line {
 596                            let line_start = Point::new(selection_start.row, 0);
 597                            buffer
 598                                .edit(Some(line_start..line_start), to_insert, Some(ctx))
 599                                .unwrap();
 600                        } else {
 601                            buffer
 602                                .edit(Some(&selection.start..&selection.end), to_insert, Some(ctx))
 603                                .unwrap();
 604                        };
 605
 606                        let new_selection_start = new_selection_start.bias_left(buffer).unwrap();
 607                        new_selections.push(Selection {
 608                            start: new_selection_start.clone(),
 609                            end: new_selection_start,
 610                            reversed: false,
 611                            goal_column: None,
 612                        });
 613                    });
 614                }
 615                self.update_selections(new_selections, true, ctx);
 616                self.end_transaction(ctx);
 617            } else {
 618                self.insert(clipboard_text, ctx);
 619            }
 620        }
 621    }
 622
 623    pub fn undo(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 624        self.buffer
 625            .update(ctx, |buffer, ctx| buffer.undo(Some(ctx)));
 626    }
 627
 628    pub fn redo(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 629        self.buffer
 630            .update(ctx, |buffer, ctx| buffer.redo(Some(ctx)));
 631    }
 632
 633    pub fn move_left(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 634        let app = ctx.as_ref();
 635        let mut selections = self.selections(app).to_vec();
 636        {
 637            let map = self.display_map.read(app);
 638            for selection in &mut selections {
 639                let start = selection.start.to_display_point(map, app).unwrap();
 640                let end = selection.end.to_display_point(map, app).unwrap();
 641
 642                if start != end {
 643                    selection.end = selection.start.clone();
 644                } else {
 645                    let cursor = map
 646                        .anchor_before(movement::left(map, start, app).unwrap(), Bias::Left, app)
 647                        .unwrap();
 648                    selection.start = cursor.clone();
 649                    selection.end = cursor;
 650                }
 651                selection.reversed = false;
 652                selection.goal_column = None;
 653            }
 654        }
 655        self.update_selections(selections, true, ctx);
 656    }
 657
 658    pub fn select_left(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 659        let mut selections = self.selections(ctx.as_ref()).to_vec();
 660        {
 661            let buffer = self.buffer.read(ctx);
 662            let map = self.display_map.read(ctx);
 663            for selection in &mut selections {
 664                let head = selection
 665                    .head()
 666                    .to_display_point(map, ctx.as_ref())
 667                    .unwrap();
 668                let cursor = map
 669                    .anchor_before(
 670                        movement::left(map, head, ctx.as_ref()).unwrap(),
 671                        Bias::Left,
 672                        ctx.as_ref(),
 673                    )
 674                    .unwrap();
 675                selection.set_head(&buffer, cursor);
 676                selection.goal_column = None;
 677            }
 678        }
 679        self.update_selections(selections, true, ctx);
 680    }
 681
 682    pub fn move_right(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 683        let mut selections = self.selections(ctx.as_ref()).to_vec();
 684        {
 685            let app = ctx.as_ref();
 686            let map = self.display_map.read(app);
 687            for selection in &mut selections {
 688                let start = selection.start.to_display_point(map, app).unwrap();
 689                let end = selection.end.to_display_point(map, app).unwrap();
 690
 691                if start != end {
 692                    selection.start = selection.end.clone();
 693                } else {
 694                    let cursor = map
 695                        .anchor_before(movement::right(map, end, app).unwrap(), Bias::Right, app)
 696                        .unwrap();
 697                    selection.start = cursor.clone();
 698                    selection.end = cursor;
 699                }
 700                selection.reversed = false;
 701                selection.goal_column = None;
 702            }
 703        }
 704        self.update_selections(selections, true, ctx);
 705    }
 706
 707    pub fn select_right(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 708        let mut selections = self.selections(ctx.as_ref()).to_vec();
 709        {
 710            let app = ctx.as_ref();
 711            let buffer = self.buffer.read(app);
 712            let map = self.display_map.read(app);
 713            for selection in &mut selections {
 714                let head = selection
 715                    .head()
 716                    .to_display_point(map, ctx.as_ref())
 717                    .unwrap();
 718                let cursor = map
 719                    .anchor_before(movement::right(map, head, app).unwrap(), Bias::Right, app)
 720                    .unwrap();
 721                selection.set_head(&buffer, cursor);
 722                selection.goal_column = None;
 723            }
 724        }
 725        self.update_selections(selections, true, ctx);
 726    }
 727
 728    pub fn move_up(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 729        if self.single_line {
 730            ctx.propagate_action();
 731        } else {
 732            let mut selections = self.selections(ctx.as_ref()).to_vec();
 733            {
 734                let app = ctx.as_ref();
 735                let map = self.display_map.read(app);
 736                for selection in &mut selections {
 737                    let start = selection.start.to_display_point(map, app).unwrap();
 738                    let end = selection.end.to_display_point(map, app).unwrap();
 739                    if start != end {
 740                        selection.goal_column = None;
 741                    }
 742
 743                    let (start, goal_column) =
 744                        movement::up(map, start, selection.goal_column, app).unwrap();
 745                    let cursor = map.anchor_before(start, Bias::Left, app).unwrap();
 746                    selection.start = cursor.clone();
 747                    selection.end = cursor;
 748                    selection.goal_column = goal_column;
 749                    selection.reversed = false;
 750                }
 751            }
 752            self.update_selections(selections, true, ctx);
 753        }
 754    }
 755
 756    pub fn select_up(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 757        if self.single_line {
 758            ctx.propagate_action();
 759        } else {
 760            let mut selections = self.selections(ctx.as_ref()).to_vec();
 761            {
 762                let app = ctx.as_ref();
 763                let buffer = self.buffer.read(app);
 764                let map = self.display_map.read(app);
 765                for selection in &mut selections {
 766                    let head = selection.head().to_display_point(map, app).unwrap();
 767                    let (head, goal_column) =
 768                        movement::up(map, head, selection.goal_column, app).unwrap();
 769                    selection.set_head(&buffer, map.anchor_before(head, Bias::Left, app).unwrap());
 770                    selection.goal_column = goal_column;
 771                }
 772            }
 773            self.update_selections(selections, true, ctx);
 774        }
 775    }
 776
 777    pub fn move_down(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 778        if self.single_line {
 779            ctx.propagate_action();
 780        } else {
 781            let mut selections = self.selections(ctx.as_ref()).to_vec();
 782            {
 783                let app = ctx.as_ref();
 784                let map = self.display_map.read(app);
 785                for selection in &mut selections {
 786                    let start = selection.start.to_display_point(map, app).unwrap();
 787                    let end = selection.end.to_display_point(map, app).unwrap();
 788                    if start != end {
 789                        selection.goal_column = None;
 790                    }
 791
 792                    let (start, goal_column) =
 793                        movement::down(map, end, selection.goal_column, app).unwrap();
 794                    let cursor = map.anchor_before(start, Bias::Right, app).unwrap();
 795                    selection.start = cursor.clone();
 796                    selection.end = cursor;
 797                    selection.goal_column = goal_column;
 798                    selection.reversed = false;
 799                }
 800            }
 801            self.update_selections(selections, true, ctx);
 802        }
 803    }
 804
 805    pub fn select_down(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 806        if self.single_line {
 807            ctx.propagate_action();
 808        } else {
 809            let mut selections = self.selections(ctx.as_ref()).to_vec();
 810            {
 811                let app = ctx.as_ref();
 812                let buffer = self.buffer.read(app);
 813                let map = self.display_map.read(app);
 814                for selection in &mut selections {
 815                    let head = selection.head().to_display_point(map, app).unwrap();
 816                    let (head, goal_column) =
 817                        movement::down(map, head, selection.goal_column, app).unwrap();
 818                    selection.set_head(&buffer, map.anchor_before(head, Bias::Right, app).unwrap());
 819                    selection.goal_column = goal_column;
 820                }
 821            }
 822            self.update_selections(selections, true, ctx);
 823        }
 824    }
 825
 826    pub fn selections_in_range<'a>(
 827        &'a self,
 828        range: Range<DisplayPoint>,
 829        app: &'a AppContext,
 830    ) -> impl 'a + Iterator<Item = Range<DisplayPoint>> {
 831        let map = self.display_map.read(app);
 832
 833        let start = map.anchor_before(range.start, Bias::Left, app).unwrap();
 834        let start_index = self.selection_insertion_index(&start, app);
 835        let pending_selection = self.pending_selection.as_ref().and_then(|s| {
 836            let selection_range = s.display_range(map, app);
 837            if selection_range.start <= range.end || selection_range.end <= range.end {
 838                Some(selection_range)
 839            } else {
 840                None
 841            }
 842        });
 843        self.selections(app)[start_index..]
 844            .iter()
 845            .map(move |s| s.display_range(map, app))
 846            .take_while(move |r| r.start <= range.end || r.end <= range.end)
 847            .chain(pending_selection)
 848    }
 849
 850    fn selection_insertion_index(&self, start: &Anchor, app: &AppContext) -> usize {
 851        let buffer = self.buffer.read(app);
 852        let selections = self.selections(app);
 853        match selections.binary_search_by(|probe| probe.start.cmp(&start, buffer).unwrap()) {
 854            Ok(index) => index,
 855            Err(index) => {
 856                if index > 0
 857                    && selections[index - 1].end.cmp(&start, buffer).unwrap() == Ordering::Greater
 858                {
 859                    index - 1
 860                } else {
 861                    index
 862                }
 863            }
 864        }
 865    }
 866
 867    fn selections<'a>(&self, app: &'a AppContext) -> &'a [Selection] {
 868        self.buffer
 869            .read(app)
 870            .selections(self.selection_set_id)
 871            .unwrap()
 872    }
 873
 874    fn update_selections(
 875        &mut self,
 876        mut selections: Vec<Selection>,
 877        autoscroll: bool,
 878        ctx: &mut ViewContext<Self>,
 879    ) {
 880        // Merge overlapping selections.
 881        let buffer = self.buffer.read(ctx);
 882        let mut i = 1;
 883        while i < selections.len() {
 884            if selections[i - 1]
 885                .end
 886                .cmp(&selections[i].start, buffer)
 887                .unwrap()
 888                >= Ordering::Equal
 889            {
 890                let removed = selections.remove(i);
 891                if removed.start.cmp(&selections[i - 1].start, buffer).unwrap() < Ordering::Equal {
 892                    selections[i - 1].start = removed.start;
 893                }
 894                if removed.end.cmp(&selections[i - 1].end, buffer).unwrap() > Ordering::Equal {
 895                    selections[i - 1].end = removed.end;
 896                }
 897            } else {
 898                i += 1;
 899            }
 900        }
 901
 902        self.buffer.update(ctx, |buffer, ctx| {
 903            buffer
 904                .update_selection_set(self.selection_set_id, selections, Some(ctx))
 905                .unwrap()
 906        });
 907        self.pause_cursor_blinking(ctx);
 908
 909        if autoscroll {
 910            *self.autoscroll_requested.lock() = true;
 911            ctx.notify();
 912        }
 913    }
 914
 915    fn start_transaction(&self, ctx: &mut ViewContext<Self>) {
 916        self.buffer.update(ctx, |buffer, _| {
 917            buffer
 918                .start_transaction(Some(self.selection_set_id))
 919                .unwrap()
 920        });
 921    }
 922
 923    fn end_transaction(&self, ctx: &mut ViewContext<Self>) {
 924        self.buffer.update(ctx, |buffer, ctx| {
 925            buffer
 926                .end_transaction(Some(self.selection_set_id), Some(ctx))
 927                .unwrap()
 928        });
 929    }
 930
 931    pub fn page_up(&mut self, _: &(), _: &mut ViewContext<Self>) {
 932        log::info!("BufferView::page_up");
 933    }
 934
 935    pub fn page_down(&mut self, _: &(), _: &mut ViewContext<Self>) {
 936        log::info!("BufferView::page_down");
 937    }
 938
 939    pub fn fold(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 940        use super::RangeExt;
 941
 942        let mut fold_ranges = Vec::new();
 943
 944        let app = ctx.as_ref();
 945        let map = self.display_map.read(app);
 946        for selection in self.selections(app) {
 947            let (start, end) = selection.display_range(map, app).sorted();
 948            let buffer_start_row = start.to_buffer_point(map, Bias::Left, app).unwrap().row;
 949
 950            for row in (0..=end.row()).rev() {
 951                if self.is_line_foldable(row, app) && !map.is_line_folded(row) {
 952                    let fold_range = self.foldable_range_for_line(row, app).unwrap();
 953                    if fold_range.end.row >= buffer_start_row {
 954                        fold_ranges.push(fold_range);
 955                        if row <= start.row() {
 956                            break;
 957                        }
 958                    }
 959                }
 960            }
 961        }
 962
 963        if !fold_ranges.is_empty() {
 964            self.display_map.update(ctx, |map, ctx| {
 965                map.fold(fold_ranges, ctx).unwrap();
 966            });
 967            *self.autoscroll_requested.lock() = true;
 968        }
 969    }
 970
 971    pub fn unfold(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
 972        use super::RangeExt;
 973
 974        let app = ctx.as_ref();
 975        let map = self.display_map.read(app);
 976        let buffer = self.buffer.read(app);
 977        let ranges = self
 978            .selections(app)
 979            .iter()
 980            .map(|s| {
 981                let (start, end) = s.display_range(map, app).sorted();
 982                let mut start = start.to_buffer_point(map, Bias::Left, app).unwrap();
 983                let mut end = end.to_buffer_point(map, Bias::Left, app).unwrap();
 984                start.column = 0;
 985                end.column = buffer.line_len(end.row).unwrap();
 986                start..end
 987            })
 988            .collect::<Vec<_>>();
 989
 990        self.display_map.update(ctx, |map, ctx| {
 991            map.unfold(ranges, ctx).unwrap();
 992        });
 993        *self.autoscroll_requested.lock() = true;
 994    }
 995
 996    fn is_line_foldable(&self, display_row: u32, app: &AppContext) -> bool {
 997        let max_point = self.max_point(app);
 998        if display_row >= max_point.row() {
 999            false
1000        } else {
1001            let (start_indent, is_blank) = self.line_indent(display_row, app).unwrap();
1002            if is_blank {
1003                false
1004            } else {
1005                for display_row in display_row + 1..=max_point.row() {
1006                    let (indent, is_blank) = self.line_indent(display_row, app).unwrap();
1007                    if !is_blank {
1008                        return indent > start_indent;
1009                    }
1010                }
1011                false
1012            }
1013        }
1014    }
1015
1016    fn line_indent(&self, display_row: u32, app: &AppContext) -> Result<(usize, bool)> {
1017        let mut indent = 0;
1018        let mut is_blank = true;
1019        for c in self
1020            .display_map
1021            .read(app)
1022            .chars_at(DisplayPoint::new(display_row, 0), app)?
1023        {
1024            if c == ' ' {
1025                indent += 1;
1026            } else {
1027                is_blank = c == '\n';
1028                break;
1029            }
1030        }
1031        Ok((indent, is_blank))
1032    }
1033
1034    fn foldable_range_for_line(&self, start_row: u32, app: &AppContext) -> Result<Range<Point>> {
1035        let map = self.display_map.read(app);
1036        let max_point = self.max_point(app);
1037
1038        let (start_indent, _) = self.line_indent(start_row, app)?;
1039        let start = DisplayPoint::new(start_row, self.line_len(start_row, app)?);
1040        let mut end = None;
1041        for row in start_row + 1..=max_point.row() {
1042            let (indent, is_blank) = self.line_indent(row, app)?;
1043            if !is_blank && indent <= start_indent {
1044                end = Some(DisplayPoint::new(row - 1, self.line_len(row - 1, app)?));
1045                break;
1046            }
1047        }
1048
1049        let end = end.unwrap_or(max_point);
1050        return Ok(start.to_buffer_point(map, Bias::Left, app)?
1051            ..end.to_buffer_point(map, Bias::Left, app)?);
1052    }
1053
1054    pub fn fold_selected_ranges(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
1055        self.display_map.update(ctx, |map, ctx| {
1056            let buffer = self.buffer.read(ctx);
1057            let ranges = self
1058                .selections(ctx.as_ref())
1059                .iter()
1060                .map(|s| s.range(buffer))
1061                .collect::<Vec<_>>();
1062            map.fold(ranges, ctx).unwrap();
1063        });
1064    }
1065
1066    pub fn line(&self, display_row: u32, app: &AppContext) -> Result<String> {
1067        self.display_map.read(app).line(display_row, app)
1068    }
1069
1070    pub fn line_len(&self, display_row: u32, app: &AppContext) -> Result<u32> {
1071        self.display_map.read(app).line_len(display_row, app)
1072    }
1073
1074    pub fn rightmost_point(&self, app: &AppContext) -> DisplayPoint {
1075        self.display_map.read(app).rightmost_point()
1076    }
1077
1078    pub fn max_point(&self, app: &AppContext) -> DisplayPoint {
1079        self.display_map.read(app).max_point(app)
1080    }
1081
1082    pub fn text(&self, app: &AppContext) -> String {
1083        self.display_map.read(app).text(app)
1084    }
1085
1086    pub fn font_size(&self) -> f32 {
1087        smol::block_on(self.settings.read()).buffer_font_size
1088    }
1089
1090    pub fn font_ascent(&self, font_cache: &FontCache) -> f32 {
1091        let settings = smol::block_on(self.settings.read());
1092        let font_id = font_cache.default_font(settings.buffer_font_family);
1093        let ascent = font_cache.metric(font_id, |m| m.ascent);
1094        font_cache.scale_metric(ascent, font_id, settings.buffer_font_size)
1095    }
1096
1097    pub fn font_descent(&self, font_cache: &FontCache) -> f32 {
1098        let settings = smol::block_on(self.settings.read());
1099        let font_id = font_cache.default_font(settings.buffer_font_family);
1100        let ascent = font_cache.metric(font_id, |m| m.descent);
1101        font_cache.scale_metric(ascent, font_id, settings.buffer_font_size)
1102    }
1103
1104    pub fn line_height(&self, font_cache: &FontCache) -> f32 {
1105        let settings = smol::block_on(self.settings.read());
1106        let font_id = font_cache.default_font(settings.buffer_font_family);
1107        font_cache.line_height(font_id, settings.buffer_font_size)
1108    }
1109
1110    pub fn em_width(&self, font_cache: &FontCache) -> f32 {
1111        let settings = smol::block_on(self.settings.read());
1112        let font_id = font_cache.default_font(settings.buffer_font_family);
1113        font_cache.em_width(font_id, settings.buffer_font_size)
1114    }
1115
1116    // TODO: Can we make this not return a result?
1117    pub fn max_line_number_width(
1118        &self,
1119        font_cache: &FontCache,
1120        layout_cache: &TextLayoutCache,
1121        app: &AppContext,
1122    ) -> Result<f32> {
1123        let settings = smol::block_on(self.settings.read());
1124        let font_size = settings.buffer_font_size;
1125        let font_id =
1126            font_cache.select_font(settings.buffer_font_family, &FontProperties::new())?;
1127        let digit_count = ((self.buffer.read(app).max_point().row + 1) as f32)
1128            .log10()
1129            .floor() as usize
1130            + 1;
1131
1132        Ok(layout_cache
1133            .layout_str(
1134                "1".repeat(digit_count).as_str(),
1135                font_size,
1136                &[(0..digit_count, font_id)],
1137            )
1138            .width)
1139    }
1140
1141    pub fn layout_line_numbers(
1142        &self,
1143        viewport_height: f32,
1144        font_cache: &FontCache,
1145        layout_cache: &TextLayoutCache,
1146        app: &AppContext,
1147    ) -> Result<Vec<Arc<text_layout::Line>>> {
1148        let display_map = self.display_map.read(app);
1149
1150        let settings = smol::block_on(self.settings.read());
1151        let font_size = settings.buffer_font_size;
1152        let font_id =
1153            font_cache.select_font(settings.buffer_font_family, &FontProperties::new())?;
1154
1155        let start_row = self.scroll_position().y() as usize;
1156        let end_row = cmp::min(
1157            self.max_point(app).row() as usize,
1158            start_row + (viewport_height / self.line_height(font_cache)).ceil() as usize,
1159        );
1160        let line_count = end_row - start_row + 1;
1161
1162        let mut layouts = Vec::with_capacity(line_count);
1163        let mut line_number = String::new();
1164        for buffer_row in display_map.buffer_rows(start_row as u32)?.take(line_count) {
1165            line_number.clear();
1166            write!(&mut line_number, "{}", buffer_row + 1).unwrap();
1167            layouts.push(layout_cache.layout_str(
1168                &line_number,
1169                font_size,
1170                &[(0..line_number.len(), font_id)],
1171            ));
1172        }
1173
1174        Ok(layouts)
1175    }
1176
1177    pub fn layout_lines(
1178        &self,
1179        mut rows: Range<u32>,
1180        font_cache: &FontCache,
1181        layout_cache: &TextLayoutCache,
1182        app: &AppContext,
1183    ) -> Result<Vec<Arc<text_layout::Line>>> {
1184        let display_map = self.display_map.read(app);
1185
1186        rows.end = cmp::min(rows.end, display_map.max_point(app).row() + 1);
1187        if rows.start >= rows.end {
1188            return Ok(Vec::new());
1189        }
1190
1191        let settings = smol::block_on(self.settings.read());
1192        let font_id =
1193            font_cache.select_font(settings.buffer_font_family, &FontProperties::new())?;
1194        let font_size = settings.buffer_font_size;
1195
1196        let mut layouts = Vec::with_capacity(rows.len());
1197        let mut line = String::new();
1198        let mut line_len = 0;
1199        let mut row = rows.start;
1200        let chars = display_map
1201            .chars_at(DisplayPoint::new(rows.start, 0), app)
1202            .unwrap();
1203        for char in chars.chain(Some('\n')) {
1204            if char == '\n' {
1205                layouts.push(layout_cache.layout_str(&line, font_size, &[(0..line_len, font_id)]));
1206                line.clear();
1207                line_len = 0;
1208                row += 1;
1209                if row == rows.end {
1210                    break;
1211                }
1212            } else {
1213                line_len += 1;
1214                line.push(char);
1215            }
1216        }
1217
1218        Ok(layouts)
1219    }
1220
1221    pub fn layout_line(
1222        &self,
1223        row: u32,
1224        font_cache: &FontCache,
1225        layout_cache: &TextLayoutCache,
1226        app: &AppContext,
1227    ) -> Result<Arc<text_layout::Line>> {
1228        let settings = smol::block_on(self.settings.read());
1229        let font_id =
1230            font_cache.select_font(settings.buffer_font_family, &FontProperties::new())?;
1231
1232        let line = self.line(row, app)?;
1233
1234        Ok(layout_cache.layout_str(
1235            &line,
1236            settings.buffer_font_size,
1237            &[(0..self.line_len(row, app)? as usize, font_id)],
1238        ))
1239    }
1240
1241    fn next_blink_epoch(&mut self) -> usize {
1242        self.blink_epoch += 1;
1243        self.blink_epoch
1244    }
1245
1246    fn pause_cursor_blinking(&mut self, ctx: &mut ViewContext<Self>) {
1247        self.cursors_visible = true;
1248        ctx.notify();
1249
1250        let epoch = self.next_blink_epoch();
1251        ctx.spawn(
1252            async move {
1253                Timer::after(CURSOR_BLINK_INTERVAL).await;
1254                epoch
1255            },
1256            Self::resume_cursor_blinking,
1257        )
1258        .detach();
1259    }
1260
1261    fn resume_cursor_blinking(&mut self, epoch: usize, ctx: &mut ViewContext<Self>) {
1262        if epoch == self.blink_epoch {
1263            self.blinking_paused = false;
1264            self.blink_cursors(epoch, ctx);
1265        }
1266    }
1267
1268    fn blink_cursors(&mut self, epoch: usize, ctx: &mut ViewContext<Self>) {
1269        if epoch == self.blink_epoch && self.focused && !self.blinking_paused {
1270            self.cursors_visible = !self.cursors_visible;
1271            ctx.notify();
1272
1273            let epoch = self.next_blink_epoch();
1274            ctx.spawn(
1275                async move {
1276                    Timer::after(CURSOR_BLINK_INTERVAL).await;
1277                    epoch
1278                },
1279                Self::blink_cursors,
1280            )
1281            .detach();
1282        }
1283    }
1284
1285    pub fn cursors_visible(&self) -> bool {
1286        self.cursors_visible
1287    }
1288
1289    fn on_buffer_changed(&mut self, _: ModelHandle<Buffer>, ctx: &mut ViewContext<Self>) {
1290        ctx.notify();
1291    }
1292
1293    fn on_display_map_changed(&mut self, _: ModelHandle<DisplayMap>, ctx: &mut ViewContext<Self>) {
1294        ctx.notify();
1295    }
1296
1297    fn on_buffer_event(
1298        &mut self,
1299        _: ModelHandle<Buffer>,
1300        event: &buffer::Event,
1301        ctx: &mut ViewContext<Self>,
1302    ) {
1303        match event {
1304            buffer::Event::Edited(_) => ctx.emit(Event::Edited),
1305            buffer::Event::Dirtied => ctx.emit(Event::Dirtied),
1306            buffer::Event::Saved => ctx.emit(Event::Saved),
1307            buffer::Event::FileHandleChanged => ctx.emit(Event::FileHandleChanged),
1308        }
1309    }
1310}
1311
1312pub enum Event {
1313    Activate,
1314    Edited,
1315    Blurred,
1316    Dirtied,
1317    Saved,
1318    FileHandleChanged,
1319}
1320
1321impl Entity for BufferView {
1322    type Event = Event;
1323}
1324
1325impl View for BufferView {
1326    fn render<'a>(&self, app: &AppContext) -> ElementBox {
1327        BufferElement::new(self.handle.upgrade(app).unwrap()).boxed()
1328    }
1329
1330    fn ui_name() -> &'static str {
1331        "BufferView"
1332    }
1333
1334    fn on_focus(&mut self, ctx: &mut ViewContext<Self>) {
1335        self.focused = true;
1336        self.blink_cursors(self.blink_epoch, ctx);
1337    }
1338
1339    fn on_blur(&mut self, ctx: &mut ViewContext<Self>) {
1340        self.focused = false;
1341        self.cursors_visible = false;
1342        ctx.emit(Event::Blurred);
1343        ctx.notify();
1344    }
1345}
1346
1347impl workspace::ItemView for BufferView {
1348    fn should_activate_item_on_event(event: &Self::Event) -> bool {
1349        matches!(event, Event::Activate)
1350    }
1351
1352    fn should_update_tab_on_event(event: &Self::Event) -> bool {
1353        matches!(
1354            event,
1355            Event::Saved | Event::Dirtied | Event::FileHandleChanged
1356        )
1357    }
1358
1359    fn title(&self, app: &AppContext) -> std::string::String {
1360        let filename = self.file.as_ref().and_then(|file| file.file_name(app));
1361        if let Some(name) = filename {
1362            name.to_string_lossy().into()
1363        } else {
1364            "untitled".into()
1365        }
1366    }
1367
1368    fn entry_id(&self, _: &AppContext) -> Option<(usize, Arc<Path>)> {
1369        self.file.as_ref().map(|file| file.entry_id())
1370    }
1371
1372    fn clone_on_split(&self, ctx: &mut ViewContext<Self>) -> Option<Self>
1373    where
1374        Self: Sized,
1375    {
1376        let clone = BufferView::for_buffer(
1377            self.buffer.clone(),
1378            self.file.clone(),
1379            self.settings.clone(),
1380            ctx,
1381        );
1382        *clone.scroll_position.lock() = *self.scroll_position.lock();
1383        Some(clone)
1384    }
1385
1386    fn save(&self, ctx: &mut ViewContext<Self>) -> LocalBoxFuture<'static, Result<()>> {
1387        if let Some(file) = self.file.as_ref() {
1388            self.buffer
1389                .update(ctx, |buffer, ctx| buffer.save(file, ctx))
1390        } else {
1391            Box::pin(async { Ok(()) })
1392        }
1393    }
1394
1395    fn is_dirty(&self, ctx: &AppContext) -> bool {
1396        self.buffer.read(ctx).is_dirty()
1397    }
1398}
1399
1400#[cfg(test)]
1401mod tests {
1402    use super::*;
1403    use crate::{editor::Point, settings, test::sample_text};
1404    use anyhow::Error;
1405    use gpui::App;
1406    use unindent::Unindent;
1407
1408    #[test]
1409    fn test_selection_with_mouse() {
1410        App::test((), |app| {
1411            let buffer = app.add_model(|_| Buffer::new(0, "aaaaaa\nbbbbbb\ncccccc\ndddddd\n"));
1412            let settings = settings::channel(&app.font_cache()).unwrap().1;
1413            let (_, buffer_view) =
1414                app.add_window(|ctx| BufferView::for_buffer(buffer, None, settings, ctx));
1415
1416            buffer_view.update(app, |view, ctx| {
1417                view.begin_selection(DisplayPoint::new(2, 2), false, ctx);
1418            });
1419
1420            let view = buffer_view.read(app);
1421            let selections = view
1422                .selections_in_range(
1423                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1424                    app.as_ref(),
1425                )
1426                .collect::<Vec<_>>();
1427            assert_eq!(
1428                selections,
1429                [DisplayPoint::new(2, 2)..DisplayPoint::new(2, 2)]
1430            );
1431
1432            buffer_view.update(app, |view, ctx| {
1433                view.update_selection(DisplayPoint::new(3, 3), Vector2F::zero(), ctx);
1434            });
1435
1436            let view = buffer_view.read(app);
1437            let selections = view
1438                .selections_in_range(
1439                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1440                    app.as_ref(),
1441                )
1442                .collect::<Vec<_>>();
1443            assert_eq!(
1444                selections,
1445                [DisplayPoint::new(2, 2)..DisplayPoint::new(3, 3)]
1446            );
1447
1448            buffer_view.update(app, |view, ctx| {
1449                view.update_selection(DisplayPoint::new(1, 1), Vector2F::zero(), ctx);
1450            });
1451
1452            let view = buffer_view.read(app);
1453            let selections = view
1454                .selections_in_range(
1455                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1456                    app.as_ref(),
1457                )
1458                .collect::<Vec<_>>();
1459            assert_eq!(
1460                selections,
1461                [DisplayPoint::new(2, 2)..DisplayPoint::new(1, 1)]
1462            );
1463
1464            buffer_view.update(app, |view, ctx| {
1465                view.end_selection(ctx);
1466                view.update_selection(DisplayPoint::new(3, 3), Vector2F::zero(), ctx);
1467            });
1468
1469            let view = buffer_view.read(app);
1470            let selections = view
1471                .selections_in_range(
1472                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1473                    app.as_ref(),
1474                )
1475                .collect::<Vec<_>>();
1476            assert_eq!(
1477                selections,
1478                [DisplayPoint::new(2, 2)..DisplayPoint::new(1, 1)]
1479            );
1480
1481            buffer_view.update(app, |view, ctx| {
1482                view.begin_selection(DisplayPoint::new(3, 3), true, ctx);
1483                view.update_selection(DisplayPoint::new(0, 0), Vector2F::zero(), ctx);
1484            });
1485
1486            let view = buffer_view.read(app);
1487            let selections = view
1488                .selections_in_range(
1489                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1490                    app.as_ref(),
1491                )
1492                .collect::<Vec<_>>();
1493            assert_eq!(
1494                selections,
1495                [
1496                    DisplayPoint::new(2, 2)..DisplayPoint::new(1, 1),
1497                    DisplayPoint::new(3, 3)..DisplayPoint::new(0, 0)
1498                ]
1499            );
1500
1501            buffer_view.update(app, |view, ctx| {
1502                view.end_selection(ctx);
1503            });
1504
1505            let view = buffer_view.read(app);
1506            let selections = view
1507                .selections_in_range(
1508                    DisplayPoint::zero()..view.max_point(app.as_ref()),
1509                    app.as_ref(),
1510                )
1511                .collect::<Vec<_>>();
1512            assert_eq!(
1513                selections,
1514                [DisplayPoint::new(3, 3)..DisplayPoint::new(0, 0)]
1515            );
1516        });
1517    }
1518
1519    #[test]
1520    fn test_layout_line_numbers() {
1521        App::test((), |app| {
1522            let layout_cache = TextLayoutCache::new(app.platform().fonts());
1523            let font_cache = app.font_cache().clone();
1524
1525            let buffer = app.add_model(|_| Buffer::new(0, sample_text(6, 6)));
1526
1527            let settings = settings::channel(&font_cache).unwrap().1;
1528            let (_, view) =
1529                app.add_window(|ctx| BufferView::for_buffer(buffer.clone(), None, settings, ctx));
1530
1531            let layouts = view
1532                .read(app)
1533                .layout_line_numbers(1000.0, &font_cache, &layout_cache, app.as_ref())
1534                .unwrap();
1535            assert_eq!(layouts.len(), 6);
1536        })
1537    }
1538
1539    #[test]
1540    fn test_fold() {
1541        App::test((), |app| {
1542            let buffer = app.add_model(|_| {
1543                Buffer::new(
1544                    0,
1545                    "
1546                    impl Foo {
1547                        // Hello!
1548
1549                        fn a() {
1550                            1
1551                        }
1552
1553                        fn b() {
1554                            2
1555                        }
1556
1557                        fn c() {
1558                            3
1559                        }
1560                    }
1561                "
1562                    .unindent(),
1563                )
1564            });
1565            let settings = settings::channel(&app.font_cache()).unwrap().1;
1566            let (_, view) =
1567                app.add_window(|ctx| BufferView::for_buffer(buffer.clone(), None, settings, ctx));
1568
1569            view.update(app, |view, ctx| {
1570                view.select_display_ranges(
1571                    &[DisplayPoint::new(8, 0)..DisplayPoint::new(12, 0)],
1572                    ctx,
1573                )
1574                .unwrap();
1575                view.fold(&(), ctx);
1576                assert_eq!(
1577                    view.text(ctx.as_ref()),
1578                    "
1579                    impl Foo {
1580                        // Hello!
1581
1582                        fn a() {
1583                            1
1584                        }
1585
1586                        fn b() {…
1587                        }
1588
1589                        fn c() {…
1590                        }
1591                    }
1592                "
1593                    .unindent(),
1594                );
1595
1596                view.fold(&(), ctx);
1597                assert_eq!(
1598                    view.text(ctx.as_ref()),
1599                    "
1600                    impl Foo {…
1601                    }
1602                "
1603                    .unindent(),
1604                );
1605
1606                view.unfold(&(), ctx);
1607                assert_eq!(
1608                    view.text(ctx.as_ref()),
1609                    "
1610                    impl Foo {
1611                        // Hello!
1612
1613                        fn a() {
1614                            1
1615                        }
1616
1617                        fn b() {…
1618                        }
1619
1620                        fn c() {…
1621                        }
1622                    }
1623                "
1624                    .unindent(),
1625                );
1626
1627                view.unfold(&(), ctx);
1628                assert_eq!(view.text(ctx.as_ref()), buffer.read(ctx).text());
1629            });
1630        });
1631    }
1632
1633    #[test]
1634    fn test_move_cursor() -> Result<()> {
1635        App::test((), |app| {
1636            let buffer = app.add_model(|_| Buffer::new(0, sample_text(6, 6)));
1637            let settings = settings::channel(&app.font_cache()).unwrap().1;
1638            let (_, view) =
1639                app.add_window(|ctx| BufferView::for_buffer(buffer.clone(), None, settings, ctx));
1640
1641            buffer.update(app, |buffer, ctx| {
1642                buffer.edit(
1643                    vec![
1644                        Point::new(1, 0)..Point::new(1, 0),
1645                        Point::new(1, 1)..Point::new(1, 1),
1646                    ],
1647                    "\t",
1648                    Some(ctx),
1649                )
1650            })?;
1651
1652            view.update(app, |view, ctx| {
1653                view.move_down(&(), ctx);
1654                assert_eq!(
1655                    view.selection_ranges(ctx.as_ref()),
1656                    &[DisplayPoint::new(1, 0)..DisplayPoint::new(1, 0)]
1657                );
1658                view.move_right(&(), ctx);
1659                assert_eq!(
1660                    view.selection_ranges(ctx.as_ref()),
1661                    &[DisplayPoint::new(1, 4)..DisplayPoint::new(1, 4)]
1662                );
1663                Ok::<(), Error>(())
1664            })?;
1665
1666            Ok(())
1667        })
1668    }
1669
1670    #[test]
1671    fn test_backspace() {
1672        App::test((), |app| {
1673            let buffer = app.add_model(|_| {
1674                Buffer::new(0, "one two three\nfour five six\nseven eight nine\nten\n")
1675            });
1676            let settings = settings::channel(&app.font_cache()).unwrap().1;
1677            let (_, view) =
1678                app.add_window(|ctx| BufferView::for_buffer(buffer.clone(), None, settings, ctx));
1679
1680            view.update(app, |view, ctx| {
1681                view.select_display_ranges(
1682                    &[
1683                        // an empty selection - the preceding character is deleted
1684                        DisplayPoint::new(0, 2)..DisplayPoint::new(0, 2),
1685                        // one character selected - it is deleted
1686                        DisplayPoint::new(1, 3)..DisplayPoint::new(1, 4),
1687                        // a line suffix selected - it is deleted
1688                        DisplayPoint::new(2, 6)..DisplayPoint::new(3, 0),
1689                    ],
1690                    ctx,
1691                )
1692                .unwrap();
1693                view.backspace(&(), ctx);
1694            });
1695
1696            assert_eq!(
1697                buffer.read(app).text(),
1698                "oe two three\nfou five six\nseven ten\n"
1699            );
1700        })
1701    }
1702
1703    #[test]
1704    fn test_clipboard() {
1705        App::test((), |app| {
1706            let buffer = app.add_model(|_| Buffer::new(0, "one two three four five six "));
1707            let settings = settings::channel(&app.font_cache()).unwrap().1;
1708            let view = app
1709                .add_window(|ctx| BufferView::for_buffer(buffer.clone(), None, settings, ctx))
1710                .1;
1711
1712            // Cut with three selections. Clipboard text is divided into three slices.
1713            view.update(app, |view, ctx| {
1714                view.select_ranges(&[0..4, 8..14, 19..24], ctx).unwrap();
1715                view.cut(&(), ctx);
1716            });
1717            assert_eq!(view.read(app).text(app.as_ref()), "two four six ");
1718
1719            // Paste with three cursors. Each cursor pastes one slice of the clipboard text.
1720            view.update(app, |view, ctx| {
1721                view.select_ranges(&[4..4, 9..9, 13..13], ctx).unwrap();
1722                view.paste(&(), ctx);
1723            });
1724            assert_eq!(
1725                view.read(app).text(app.as_ref()),
1726                "two one four three six five "
1727            );
1728            assert_eq!(
1729                view.read(app).selection_ranges(app.as_ref()),
1730                &[
1731                    DisplayPoint::new(0, 8)..DisplayPoint::new(0, 8),
1732                    DisplayPoint::new(0, 19)..DisplayPoint::new(0, 19),
1733                    DisplayPoint::new(0, 28)..DisplayPoint::new(0, 28)
1734                ]
1735            );
1736
1737            // Paste again but with only two cursors. Since the number of cursors doesn't
1738            // match the number of slices in the clipboard, the entire clipboard text
1739            // is pasted at each cursor.
1740            view.update(app, |view, ctx| {
1741                view.select_ranges(&[0..0, 28..28], ctx).unwrap();
1742                view.insert(&"( ".to_string(), ctx);
1743                view.paste(&(), ctx);
1744                view.insert(&") ".to_string(), ctx);
1745            });
1746            assert_eq!(
1747                view.read(app).text(app.as_ref()),
1748                "( one three five ) two one four three six five ( one three five ) "
1749            );
1750
1751            view.update(app, |view, ctx| {
1752                view.select_ranges(&[0..0], ctx).unwrap();
1753                view.insert(&"123\n4567\n89\n".to_string(), ctx);
1754            });
1755            assert_eq!(
1756                view.read(app).text(app.as_ref()),
1757                "123\n4567\n89\n( one three five ) two one four three six five ( one three five ) "
1758            );
1759
1760            // Cut with three selections, one of which is full-line.
1761            view.update(app, |view, ctx| {
1762                view.select_display_ranges(
1763                    &[
1764                        DisplayPoint::new(0, 1)..DisplayPoint::new(0, 2),
1765                        DisplayPoint::new(1, 1)..DisplayPoint::new(1, 1),
1766                        DisplayPoint::new(2, 0)..DisplayPoint::new(2, 1),
1767                    ],
1768                    ctx,
1769                )
1770                .unwrap();
1771                view.cut(&(), ctx);
1772            });
1773            assert_eq!(
1774                view.read(app).text(app.as_ref()),
1775                "13\n9\n( one three five ) two one four three six five ( one three five ) "
1776            );
1777
1778            // Paste with three selections, noticing how the copied selection that was full-line
1779            // gets inserted before the second cursor.
1780            view.update(app, |view, ctx| {
1781                view.select_display_ranges(
1782                    &[
1783                        DisplayPoint::new(0, 1)..DisplayPoint::new(0, 1),
1784                        DisplayPoint::new(1, 1)..DisplayPoint::new(1, 1),
1785                        DisplayPoint::new(2, 2)..DisplayPoint::new(2, 3),
1786                    ],
1787                    ctx,
1788                )
1789                .unwrap();
1790                view.paste(&(), ctx);
1791            });
1792            assert_eq!(
1793                view.read(app).text(app.as_ref()),
1794                "123\n4567\n9\n( 8ne three five ) two one four three six five ( one three five ) "
1795            );
1796            assert_eq!(
1797                view.read(app).selection_ranges(app.as_ref()),
1798                &[
1799                    DisplayPoint::new(0, 2)..DisplayPoint::new(0, 2),
1800                    DisplayPoint::new(2, 1)..DisplayPoint::new(2, 1),
1801                    DisplayPoint::new(3, 3)..DisplayPoint::new(3, 3),
1802                ]
1803            );
1804
1805            // Copy with a single cursor only, which writes the whole line into the clipboard.
1806            view.update(app, |view, ctx| {
1807                view.select_display_ranges(
1808                    &[DisplayPoint::new(0, 1)..DisplayPoint::new(0, 1)],
1809                    ctx,
1810                )
1811                .unwrap();
1812                view.copy(&(), ctx);
1813            });
1814
1815            // Paste with three selections, noticing how the copied full-line selection is inserted
1816            // before the empty selections but replaces the selection that is non-empty.
1817            view.update(app, |view, ctx| {
1818                view.select_display_ranges(
1819                    &[
1820                        DisplayPoint::new(0, 1)..DisplayPoint::new(0, 1),
1821                        DisplayPoint::new(1, 0)..DisplayPoint::new(1, 2),
1822                        DisplayPoint::new(2, 1)..DisplayPoint::new(2, 1),
1823                    ],
1824                    ctx,
1825                )
1826                .unwrap();
1827                view.paste(&(), ctx);
1828            });
1829            assert_eq!(
1830                view.read(app).text(app.as_ref()),
1831                "123\n123\n123\n67\n123\n9\n( 8ne three five ) two one four three six five ( one three five ) "
1832            );
1833            assert_eq!(
1834                view.read(app).selection_ranges(app.as_ref()),
1835                &[
1836                    DisplayPoint::new(1, 1)..DisplayPoint::new(1, 1),
1837                    DisplayPoint::new(3, 0)..DisplayPoint::new(3, 0),
1838                    DisplayPoint::new(5, 1)..DisplayPoint::new(5, 1),
1839                ]
1840            );
1841        });
1842    }
1843
1844    impl BufferView {
1845        fn selection_ranges(&self, app: &AppContext) -> Vec<Range<DisplayPoint>> {
1846            self.selections_in_range(DisplayPoint::zero()..self.max_point(app), app)
1847                .collect::<Vec<_>>()
1848        }
1849    }
1850}