movement.rs

   1//! Movement module contains helper functions for calculating intended position
   2//! in editor given a given motion (e.g. it handles converting a "move left" command into coordinates in editor). It is exposed mostly for use by vim crate.
   3
   4use super::{Bias, DisplayPoint, DisplaySnapshot, SelectionGoal, ToDisplayPoint};
   5use crate::{
   6    DisplayRow, EditorStyle, ToOffset, ToPoint,
   7    scroll::{ScrollOffset, SharedScrollAnchor},
   8};
   9use gpui::{Pixels, WindowTextSystem};
  10use language::{CharClassifier, Point};
  11use multi_buffer::{MultiBufferOffset, MultiBufferRow, MultiBufferSnapshot};
  12use serde::Deserialize;
  13use workspace::searchable::Direction;
  14
  15use std::{ops::Range, sync::Arc};
  16
  17/// Defines search strategy for items in `movement` module.
  18/// `FindRange::SingeLine` only looks for a match on a single line at a time, whereas
  19/// `FindRange::MultiLine` keeps going until the end of a string.
  20#[derive(Clone, Copy, Debug, PartialEq, Eq, Deserialize)]
  21pub enum FindRange {
  22    SingleLine,
  23    MultiLine,
  24}
  25
  26/// TextLayoutDetails encompasses everything we need to move vertically
  27/// taking into account variable width characters.
  28pub struct TextLayoutDetails {
  29    pub(crate) text_system: Arc<WindowTextSystem>,
  30    pub(crate) editor_style: EditorStyle,
  31    pub(crate) rem_size: Pixels,
  32    pub scroll_anchor: SharedScrollAnchor,
  33    pub visible_rows: Option<f64>,
  34    pub vertical_scroll_margin: ScrollOffset,
  35}
  36
  37/// Returns a column to the left of the current point, wrapping
  38/// to the previous line if that point is at the start of line.
  39pub fn left(map: &DisplaySnapshot, mut point: DisplayPoint) -> DisplayPoint {
  40    if point.column() > 0 {
  41        *point.column_mut() -= 1;
  42    } else if point.row().0 > 0 {
  43        *point.row_mut() -= 1;
  44        *point.column_mut() = map.line_len(point.row());
  45    }
  46    map.clip_point(point, Bias::Left)
  47}
  48
  49/// Returns a column to the left of the current point, doing nothing if
  50/// that point is already at the start of line.
  51pub fn saturating_left(map: &DisplaySnapshot, mut point: DisplayPoint) -> DisplayPoint {
  52    if point.column() > 0 {
  53        *point.column_mut() -= 1;
  54    } else if point.column() == 0 {
  55        // If the current sofr_wrap mode is used, the column corresponding to the display is 0,
  56        //  which does not necessarily mean that the actual beginning of a paragraph
  57        if map.display_point_to_fold_point(point, Bias::Left).column() > 0 {
  58            return left(map, point);
  59        }
  60    }
  61    map.clip_point(point, Bias::Left)
  62}
  63
  64/// Returns a column to the right of the current point, wrapping
  65/// to the next line if that point is at the end of line.
  66pub fn right(map: &DisplaySnapshot, mut point: DisplayPoint) -> DisplayPoint {
  67    if point.column() < map.line_len(point.row()) {
  68        *point.column_mut() += 1;
  69    } else if point.row() < map.max_point().row() {
  70        *point.row_mut() += 1;
  71        *point.column_mut() = 0;
  72    }
  73    map.clip_point(point, Bias::Right)
  74}
  75
  76/// Returns a column to the right of the current point, not performing any wrapping
  77/// if that point is already at the end of line.
  78pub fn saturating_right(map: &DisplaySnapshot, mut point: DisplayPoint) -> DisplayPoint {
  79    *point.column_mut() += 1;
  80    map.clip_point(point, Bias::Right)
  81}
  82
  83/// Returns a display point for the preceding displayed line (which might be a soft-wrapped line).
  84pub fn up(
  85    map: &DisplaySnapshot,
  86    start: DisplayPoint,
  87    goal: SelectionGoal,
  88    preserve_column_at_start: bool,
  89    text_layout_details: &TextLayoutDetails,
  90) -> (DisplayPoint, SelectionGoal) {
  91    up_by_rows(
  92        map,
  93        start,
  94        1,
  95        goal,
  96        preserve_column_at_start,
  97        text_layout_details,
  98    )
  99}
 100
 101/// Returns a display point for the next displayed line (which might be a soft-wrapped line).
 102pub fn down(
 103    map: &DisplaySnapshot,
 104    start: DisplayPoint,
 105    goal: SelectionGoal,
 106    preserve_column_at_end: bool,
 107    text_layout_details: &TextLayoutDetails,
 108) -> (DisplayPoint, SelectionGoal) {
 109    down_by_rows(
 110        map,
 111        start,
 112        1,
 113        goal,
 114        preserve_column_at_end,
 115        text_layout_details,
 116    )
 117}
 118
 119pub(crate) fn up_by_rows(
 120    map: &DisplaySnapshot,
 121    start: DisplayPoint,
 122    row_count: u32,
 123    goal: SelectionGoal,
 124    preserve_column_at_start: bool,
 125    text_layout_details: &TextLayoutDetails,
 126) -> (DisplayPoint, SelectionGoal) {
 127    let goal_x = match goal {
 128        SelectionGoal::HorizontalPosition(x) => x.into(),
 129        SelectionGoal::WrappedHorizontalPosition((_, x)) => x.into(),
 130        SelectionGoal::HorizontalRange { end, .. } => end.into(),
 131        _ => map.x_for_display_point(start, text_layout_details),
 132    };
 133
 134    let prev_row = DisplayRow(start.row().0.saturating_sub(row_count));
 135    let mut point = map.clip_point(
 136        DisplayPoint::new(prev_row, map.line_len(prev_row)),
 137        Bias::Left,
 138    );
 139    if point.row() < start.row() {
 140        *point.column_mut() = map.display_column_for_x(point.row(), goal_x, text_layout_details)
 141    } else if preserve_column_at_start {
 142        return (start, goal);
 143    } else {
 144        point = DisplayPoint::new(DisplayRow(0), 0);
 145    }
 146
 147    let mut clipped_point = map.clip_point(point, Bias::Left);
 148    if clipped_point.row() < point.row() {
 149        clipped_point = map.clip_point(point, Bias::Right);
 150    }
 151    (
 152        clipped_point,
 153        SelectionGoal::HorizontalPosition(goal_x.into()),
 154    )
 155}
 156
 157pub(crate) fn down_by_rows(
 158    map: &DisplaySnapshot,
 159    start: DisplayPoint,
 160    row_count: u32,
 161    goal: SelectionGoal,
 162    preserve_column_at_end: bool,
 163    text_layout_details: &TextLayoutDetails,
 164) -> (DisplayPoint, SelectionGoal) {
 165    let goal_x = match goal {
 166        SelectionGoal::HorizontalPosition(x) => x.into(),
 167        SelectionGoal::WrappedHorizontalPosition((_, x)) => x.into(),
 168        SelectionGoal::HorizontalRange { end, .. } => end.into(),
 169        _ => map.x_for_display_point(start, text_layout_details),
 170    };
 171
 172    let new_row = DisplayRow(start.row().0 + row_count);
 173    let mut point = map.clip_point(DisplayPoint::new(new_row, 0), Bias::Right);
 174    if point.row() > start.row() {
 175        *point.column_mut() = map.display_column_for_x(point.row(), goal_x, text_layout_details)
 176    } else if preserve_column_at_end {
 177        return (start, goal);
 178    } else {
 179        point = map.max_point();
 180    }
 181
 182    let mut clipped_point = map.clip_point(point, Bias::Right);
 183    if clipped_point.row() > point.row() {
 184        clipped_point = map.clip_point(point, Bias::Left);
 185    }
 186    (
 187        clipped_point,
 188        SelectionGoal::HorizontalPosition(goal_x.into()),
 189    )
 190}
 191
 192/// Returns a position of the start of line.
 193/// If `stop_at_soft_boundaries` is true, the returned position is that of the
 194/// displayed line (e.g. it could actually be in the middle of a text line if that line is soft-wrapped).
 195/// Otherwise it's always going to be the start of a logical line.
 196pub fn line_beginning(
 197    map: &DisplaySnapshot,
 198    display_point: DisplayPoint,
 199    stop_at_soft_boundaries: bool,
 200) -> DisplayPoint {
 201    let point = display_point.to_point(map);
 202    let soft_line_start = map.clip_point(DisplayPoint::new(display_point.row(), 0), Bias::Right);
 203    let line_start = map.prev_line_boundary(point).1;
 204
 205    if stop_at_soft_boundaries && display_point != soft_line_start {
 206        soft_line_start
 207    } else {
 208        line_start
 209    }
 210}
 211
 212/// Returns the last indented position on a given line.
 213/// If `stop_at_soft_boundaries` is true, the returned [`DisplayPoint`] is that of a
 214/// displayed line (e.g. if there's soft wrap it's gonna be returned),
 215/// otherwise it's always going to be a start of a logical line.
 216pub fn indented_line_beginning(
 217    map: &DisplaySnapshot,
 218    display_point: DisplayPoint,
 219    stop_at_soft_boundaries: bool,
 220    stop_at_indent: bool,
 221) -> DisplayPoint {
 222    let point = display_point.to_point(map);
 223    let soft_line_start = map.clip_point(DisplayPoint::new(display_point.row(), 0), Bias::Right);
 224    let indent_start = Point::new(
 225        point.row,
 226        map.buffer_snapshot()
 227            .indent_size_for_line(MultiBufferRow(point.row))
 228            .len,
 229    )
 230    .to_display_point(map);
 231    let line_start = map.prev_line_boundary(point).1;
 232
 233    if stop_at_soft_boundaries && soft_line_start > indent_start && display_point != soft_line_start
 234    {
 235        soft_line_start
 236    } else if stop_at_indent && (display_point > indent_start || display_point == line_start) {
 237        indent_start
 238    } else {
 239        line_start
 240    }
 241}
 242
 243/// Returns a position of the end of line.
 244///
 245/// If `stop_at_soft_boundaries` is true, the returned position is that of the
 246/// displayed line (e.g. it could actually be in the middle of a text line if that line is soft-wrapped).
 247/// Otherwise it's always going to be the end of a logical line.
 248pub fn line_end(
 249    map: &DisplaySnapshot,
 250    display_point: DisplayPoint,
 251    stop_at_soft_boundaries: bool,
 252) -> DisplayPoint {
 253    let soft_line_end = map.clip_point(
 254        DisplayPoint::new(display_point.row(), map.line_len(display_point.row())),
 255        Bias::Left,
 256    );
 257    if stop_at_soft_boundaries && display_point != soft_line_end {
 258        soft_line_end
 259    } else {
 260        map.next_line_boundary(display_point.to_point(map)).1
 261    }
 262}
 263
 264/// Returns a position of the previous word boundary, where a word character is defined as either
 265/// uppercase letter, lowercase letter, '_' character or language-specific word character (like '-' in CSS).
 266pub fn previous_word_start(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 267    let raw_point = point.to_point(map);
 268    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 269
 270    let mut is_first_iteration = true;
 271    find_preceding_boundary_display_point(map, point, FindRange::MultiLine, &mut |left, right| {
 272        // Make alt-left skip punctuation to respect VSCode behaviour. For example: hello.| goes to |hello.
 273        if is_first_iteration
 274            && classifier.is_punctuation(right)
 275            && !classifier.is_punctuation(left)
 276            && left != '\n'
 277        {
 278            is_first_iteration = false;
 279            return false;
 280        }
 281        is_first_iteration = false;
 282
 283        (classifier.kind(left) != classifier.kind(right) && !classifier.is_whitespace(right))
 284            || left == '\n'
 285    })
 286}
 287
 288/// Returns a position of the previous word boundary, where a word character is defined as either
 289/// uppercase letter, lowercase letter, '_' character, language-specific word character (like '-' in CSS) or newline.
 290pub fn previous_word_start_or_newline(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 291    let raw_point = point.to_point(map);
 292    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 293
 294    find_preceding_boundary_display_point(map, point, FindRange::MultiLine, &mut |left, right| {
 295        (classifier.kind(left) != classifier.kind(right) && !classifier.is_whitespace(right))
 296            || left == '\n'
 297            || right == '\n'
 298    })
 299}
 300
 301/// Text movements are too greedy, making deletions too greedy too.
 302/// Makes deletions more ergonomic by potentially reducing the deletion range based on its text contents:
 303/// * whitespace sequences with length >= 2 stop the deletion after removal (despite movement jumping over the word behind the whitespaces)
 304/// * brackets stop the deletion after removal (despite movement currently not accounting for these and jumping over)
 305pub fn adjust_greedy_deletion(
 306    map: &DisplaySnapshot,
 307    delete_from: DisplayPoint,
 308    delete_until: DisplayPoint,
 309    ignore_brackets: bool,
 310) -> DisplayPoint {
 311    if delete_from == delete_until {
 312        return delete_until;
 313    }
 314    let is_backward = delete_from > delete_until;
 315    let delete_range = if is_backward {
 316        map.display_point_to_point(delete_until, Bias::Left)
 317            .to_offset(map.buffer_snapshot())
 318            ..map
 319                .display_point_to_point(delete_from, Bias::Right)
 320                .to_offset(map.buffer_snapshot())
 321    } else {
 322        map.display_point_to_point(delete_from, Bias::Left)
 323            .to_offset(map.buffer_snapshot())
 324            ..map
 325                .display_point_to_point(delete_until, Bias::Right)
 326                .to_offset(map.buffer_snapshot())
 327    };
 328
 329    let trimmed_delete_range = if ignore_brackets {
 330        delete_range
 331    } else {
 332        let brackets_in_delete_range = map
 333            .buffer_snapshot()
 334            .bracket_ranges(delete_range.clone())
 335            .into_iter()
 336            .flatten()
 337            .flat_map(|(left_bracket, right_bracket)| {
 338                [
 339                    left_bracket.start,
 340                    left_bracket.end,
 341                    right_bracket.start,
 342                    right_bracket.end,
 343                ]
 344            })
 345            .filter(|&bracket| delete_range.start < bracket && bracket < delete_range.end);
 346        let closest_bracket = if is_backward {
 347            brackets_in_delete_range.max()
 348        } else {
 349            brackets_in_delete_range.min()
 350        };
 351
 352        if is_backward {
 353            closest_bracket.unwrap_or(delete_range.start)..delete_range.end
 354        } else {
 355            delete_range.start..closest_bracket.unwrap_or(delete_range.end)
 356        }
 357    };
 358
 359    let mut whitespace_sequences = Vec::new();
 360    let mut current_offset = trimmed_delete_range.start;
 361    let mut whitespace_sequence_length = MultiBufferOffset(0);
 362    let mut whitespace_sequence_start = MultiBufferOffset(0);
 363    for ch in map
 364        .buffer_snapshot()
 365        .text_for_range(trimmed_delete_range.clone())
 366        .flat_map(str::chars)
 367    {
 368        if ch.is_whitespace() {
 369            if whitespace_sequence_length == MultiBufferOffset(0) {
 370                whitespace_sequence_start = current_offset;
 371            }
 372            whitespace_sequence_length += 1;
 373        } else {
 374            if whitespace_sequence_length >= MultiBufferOffset(2) {
 375                whitespace_sequences.push((whitespace_sequence_start, current_offset));
 376            }
 377            whitespace_sequence_start = MultiBufferOffset(0);
 378            whitespace_sequence_length = MultiBufferOffset(0);
 379        }
 380        current_offset += ch.len_utf8();
 381    }
 382    if whitespace_sequence_length >= MultiBufferOffset(2) {
 383        whitespace_sequences.push((whitespace_sequence_start, current_offset));
 384    }
 385
 386    let closest_whitespace_end = if is_backward {
 387        whitespace_sequences.last().map(|&(start, _)| start)
 388    } else {
 389        whitespace_sequences.first().map(|&(_, end)| end)
 390    };
 391
 392    closest_whitespace_end
 393        .unwrap_or_else(|| {
 394            if is_backward {
 395                trimmed_delete_range.start
 396            } else {
 397                trimmed_delete_range.end
 398            }
 399        })
 400        .to_display_point(map)
 401}
 402
 403/// Returns a position of the previous subword boundary, where a subword is defined as a run of
 404/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 405/// lowerspace characters and uppercase characters.
 406pub fn previous_subword_start(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 407    let raw_point = point.to_point(map);
 408    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 409
 410    find_preceding_boundary_display_point(map, point, FindRange::MultiLine, &mut |left, right| {
 411        is_subword_start(left, right, &classifier) || left == '\n' || right == '\n'
 412    })
 413}
 414
 415/// Returns a position of the previous subword boundary, where a subword is defined as a run of
 416/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 417/// lowerspace characters and uppercase characters or newline.
 418pub fn previous_subword_start_or_newline(
 419    map: &DisplaySnapshot,
 420    point: DisplayPoint,
 421) -> DisplayPoint {
 422    let raw_point = point.to_point(map);
 423    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 424
 425    find_preceding_boundary_display_point(map, point, FindRange::MultiLine, &mut |left, right| {
 426        (is_subword_start(left, right, &classifier)) || left == '\n' || right == '\n'
 427    })
 428}
 429
 430pub fn is_subword_start(left: char, right: char, classifier: &CharClassifier) -> bool {
 431    let is_word_start = classifier.kind(left) != classifier.kind(right) && !right.is_whitespace();
 432    let is_subword_start = classifier.is_word('-') && left == '-' && right != '-'
 433        || left == '_' && right != '_'
 434        || left != '_' && right == '_'
 435        || left.is_lowercase() && right.is_uppercase();
 436    is_word_start || is_subword_start
 437}
 438
 439/// Returns a position of the next word boundary, where a word character is defined as either
 440/// uppercase letter, lowercase letter, '_' character or language-specific word character (like '-' in CSS).
 441pub fn next_word_end(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 442    let raw_point = point.to_point(map);
 443    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 444    let mut is_first_iteration = true;
 445    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 446        // Make alt-right skip punctuation to respect VSCode behaviour. For example: |.hello goes to .hello|
 447        if is_first_iteration
 448            && classifier.is_punctuation(left)
 449            && !classifier.is_punctuation(right)
 450            && right != '\n'
 451        {
 452            is_first_iteration = false;
 453            return false;
 454        }
 455        is_first_iteration = false;
 456
 457        (classifier.kind(left) != classifier.kind(right) && !classifier.is_whitespace(left))
 458            || right == '\n'
 459    })
 460}
 461
 462/// Returns a position of the next word boundary, where a word character is defined as either
 463/// uppercase letter, lowercase letter, '_' character, language-specific word character (like '-' in CSS) or newline.
 464pub fn next_word_end_or_newline(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 465    let raw_point = point.to_point(map);
 466    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 467
 468    let mut on_starting_row = true;
 469    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 470        if left == '\n' {
 471            on_starting_row = false;
 472        }
 473        (classifier.kind(left) != classifier.kind(right)
 474            && ((on_starting_row && !left.is_whitespace())
 475                || (!on_starting_row && !right.is_whitespace())))
 476            || right == '\n'
 477    })
 478}
 479
 480/// Returns a position of the next subword boundary, where a subword is defined as a run of
 481/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 482/// lowerspace characters and uppercase characters.
 483pub fn next_subword_end(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 484    let raw_point = point.to_point(map);
 485    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 486
 487    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 488        is_subword_end(left, right, &classifier) || left == '\n' || right == '\n'
 489    })
 490}
 491
 492/// Returns a position of the next subword boundary, where a subword is defined as a run of
 493/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 494/// lowerspace characters and uppercase characters or newline.
 495pub fn next_subword_end_or_newline(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 496    let raw_point = point.to_point(map);
 497    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 498
 499    let mut on_starting_row = true;
 500    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 501        if left == '\n' {
 502            on_starting_row = false;
 503        }
 504        ((classifier.kind(left) != classifier.kind(right)
 505            || is_subword_boundary_end(left, right, &classifier))
 506            && ((on_starting_row && !left.is_whitespace())
 507                || (!on_starting_row && !right.is_whitespace())))
 508            || right == '\n'
 509    })
 510}
 511
 512pub fn is_subword_end(left: char, right: char, classifier: &CharClassifier) -> bool {
 513    let is_word_end =
 514        (classifier.kind(left) != classifier.kind(right)) && !classifier.is_whitespace(left);
 515    is_word_end || is_subword_boundary_end(left, right, classifier)
 516}
 517
 518/// Returns true if the transition from `left` to `right` is a subword boundary,
 519/// such as case changes, underscores, or dashes. Does not include word boundaries like whitespace.
 520fn is_subword_boundary_end(left: char, right: char, classifier: &CharClassifier) -> bool {
 521    classifier.is_word('-') && left != '-' && right == '-'
 522        || left != '_' && right == '_'
 523        || left == '_' && right != '_'
 524        || left.is_lowercase() && right.is_uppercase()
 525}
 526
 527/// Returns a position of the start of the current paragraph, where a paragraph
 528/// is defined as a run of non-blank lines.
 529pub fn start_of_paragraph(
 530    map: &DisplaySnapshot,
 531    display_point: DisplayPoint,
 532    mut count: usize,
 533) -> DisplayPoint {
 534    let point = display_point.to_point(map);
 535    if point.row == 0 {
 536        return DisplayPoint::zero();
 537    }
 538
 539    let mut found_non_blank_line = false;
 540    for row in (0..point.row + 1).rev() {
 541        let blank = map.buffer_snapshot().is_line_blank(MultiBufferRow(row));
 542        if found_non_blank_line && blank {
 543            if count <= 1 {
 544                return Point::new(row, 0).to_display_point(map);
 545            }
 546            count -= 1;
 547            found_non_blank_line = false;
 548        }
 549
 550        found_non_blank_line |= !blank;
 551    }
 552
 553    DisplayPoint::zero()
 554}
 555
 556/// Returns a position of the end of the current paragraph, where a paragraph
 557/// is defined as a run of non-blank lines.
 558pub fn end_of_paragraph(
 559    map: &DisplaySnapshot,
 560    display_point: DisplayPoint,
 561    mut count: usize,
 562) -> DisplayPoint {
 563    let point = display_point.to_point(map);
 564    if point.row == map.buffer_snapshot().max_row().0 {
 565        return map.max_point();
 566    }
 567
 568    let mut found_non_blank_line = false;
 569    for row in point.row..=map.buffer_snapshot().max_row().0 {
 570        let blank = map.buffer_snapshot().is_line_blank(MultiBufferRow(row));
 571        if found_non_blank_line && blank {
 572            if count <= 1 {
 573                return Point::new(row, 0).to_display_point(map);
 574            }
 575            count -= 1;
 576            found_non_blank_line = false;
 577        }
 578
 579        found_non_blank_line |= !blank;
 580    }
 581
 582    map.max_point()
 583}
 584
 585pub fn start_of_excerpt(
 586    map: &DisplaySnapshot,
 587    display_point: DisplayPoint,
 588    direction: Direction,
 589) -> DisplayPoint {
 590    let point = map.display_point_to_point(display_point, Bias::Left);
 591    let Some((_, excerpt_range)) = map.buffer_snapshot().excerpt_containing(point..point) else {
 592        return display_point;
 593    };
 594    match direction {
 595        Direction::Prev => {
 596            let Some(start_anchor) = map.anchor_in_excerpt(excerpt_range.context.start) else {
 597                return display_point;
 598            };
 599            let mut start = start_anchor.to_display_point(map);
 600            if start >= display_point && start.row() > DisplayRow(0) {
 601                let Some(excerpt) = map.buffer_snapshot().excerpt_before(start_anchor) else {
 602                    return display_point;
 603                };
 604                if let Some(start_anchor) = map.anchor_in_excerpt(excerpt.context.start) {
 605                    start = start_anchor.to_display_point(map);
 606                }
 607            }
 608            start
 609        }
 610        Direction::Next => {
 611            let Some(end_anchor) = map.anchor_in_excerpt(excerpt_range.context.end) else {
 612                return display_point;
 613            };
 614            let mut end = end_anchor.to_display_point(map);
 615            *end.row_mut() += 1;
 616            map.clip_point(end, Bias::Right)
 617        }
 618    }
 619}
 620
 621pub fn end_of_excerpt(
 622    map: &DisplaySnapshot,
 623    display_point: DisplayPoint,
 624    direction: Direction,
 625) -> DisplayPoint {
 626    let point = map.display_point_to_point(display_point, Bias::Left);
 627    let Some((_, excerpt_range)) = map.buffer_snapshot().excerpt_containing(point..point) else {
 628        return display_point;
 629    };
 630    match direction {
 631        Direction::Prev => {
 632            let Some(start_anchor) = map.anchor_in_excerpt(excerpt_range.context.start) else {
 633                return display_point;
 634            };
 635            let mut start = start_anchor.to_display_point(map);
 636            if start.row() > DisplayRow(0) {
 637                *start.row_mut() -= 1;
 638            }
 639            start = map.clip_point(start, Bias::Left);
 640            *start.column_mut() = 0;
 641            start
 642        }
 643        Direction::Next => {
 644            let Some(end_anchor) = map.anchor_in_excerpt(excerpt_range.context.end) else {
 645                return display_point;
 646            };
 647            let mut end = end_anchor.to_display_point(map);
 648            *end.column_mut() = 0;
 649            if end <= display_point {
 650                *end.row_mut() += 1;
 651                let point_end = map.display_point_to_point(end, Bias::Right);
 652                let Some((_, excerpt_range)) = map
 653                    .buffer_snapshot()
 654                    .excerpt_containing(point_end..point_end)
 655                else {
 656                    return display_point;
 657                };
 658                if let Some(end_anchor) = map.anchor_in_excerpt(excerpt_range.context.end) {
 659                    end = end_anchor.to_display_point(map);
 660                }
 661                *end.column_mut() = 0;
 662            }
 663            end
 664        }
 665    }
 666}
 667
 668/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 669/// indicated by the given predicate returning true.
 670/// The predicate is called with the character to the left and right of the candidate boundary location.
 671/// If FindRange::SingleLine is specified and no boundary is found before the start of the current line, the start of the current line will be returned.
 672pub fn find_preceding_boundary_point(
 673    buffer_snapshot: &MultiBufferSnapshot,
 674    from: Point,
 675    find_range: FindRange,
 676    is_boundary: &mut dyn FnMut(char, char) -> bool,
 677) -> Point {
 678    let mut prev_ch = None;
 679    let mut offset = from.to_offset(buffer_snapshot);
 680
 681    for ch in buffer_snapshot.reversed_chars_at(offset) {
 682        if find_range == FindRange::SingleLine && ch == '\n' {
 683            break;
 684        }
 685        if let Some(prev_ch) = prev_ch
 686            && is_boundary(ch, prev_ch)
 687        {
 688            break;
 689        }
 690
 691        offset -= ch.len_utf8();
 692        prev_ch = Some(ch);
 693    }
 694
 695    offset.to_point(buffer_snapshot)
 696}
 697
 698/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 699/// indicated by the given predicate returning true.
 700/// The predicate is called with the character to the left and right of the candidate boundary location.
 701/// If FindRange::SingleLine is specified and no boundary is found before the start of the current line, the start of the current line will be returned.
 702pub fn find_preceding_boundary_display_point(
 703    map: &DisplaySnapshot,
 704    from: DisplayPoint,
 705    find_range: FindRange,
 706    is_boundary: &mut dyn FnMut(char, char) -> bool,
 707) -> DisplayPoint {
 708    let result = find_preceding_boundary_point(
 709        map.buffer_snapshot(),
 710        from.to_point(map),
 711        find_range,
 712        is_boundary,
 713    );
 714    map.clip_point(result.to_display_point(map), Bias::Left)
 715}
 716
 717/// Scans for a boundary following the given start point until a boundary is found, indicated by the
 718/// given predicate returning true. The predicate is called with the character to the left and right
 719/// of the candidate boundary location, and will be called with `\n` characters indicating the start
 720/// or end of a line. The function supports optionally returning the point just before the boundary
 721/// is found via return_point_before_boundary.
 722pub fn find_boundary_point(
 723    map: &DisplaySnapshot,
 724    from: DisplayPoint,
 725    find_range: FindRange,
 726    is_boundary: &mut dyn FnMut(char, char) -> bool,
 727    return_point_before_boundary: bool,
 728) -> DisplayPoint {
 729    let mut offset = from.to_offset(map, Bias::Right);
 730    let mut prev_offset = offset;
 731    let mut prev_ch = None;
 732
 733    for ch in map.buffer_snapshot().chars_at(offset) {
 734        if find_range == FindRange::SingleLine && ch == '\n' {
 735            break;
 736        }
 737        if let Some(prev_ch) = prev_ch
 738            && is_boundary(prev_ch, ch)
 739        {
 740            if return_point_before_boundary {
 741                return map.clip_point(prev_offset.to_display_point(map), Bias::Right);
 742            } else {
 743                break;
 744            }
 745        }
 746        prev_offset = offset;
 747        offset += ch.len_utf8();
 748        prev_ch = Some(ch);
 749    }
 750    map.clip_point(offset.to_display_point(map), Bias::Right)
 751}
 752
 753pub fn find_preceding_boundary_trail(
 754    map: &DisplaySnapshot,
 755    head: DisplayPoint,
 756    is_boundary: &mut dyn FnMut(char, char) -> bool,
 757) -> (Option<DisplayPoint>, DisplayPoint) {
 758    let mut offset = head.to_offset(map, Bias::Left);
 759    let mut trail_offset = None;
 760
 761    let mut prev_ch = map.buffer_snapshot().chars_at(offset).next();
 762    let mut forward = map.buffer_snapshot().reversed_chars_at(offset).peekable();
 763
 764    // Skip newlines
 765    while let Some(&ch) = forward.peek() {
 766        if ch == '\n' {
 767            prev_ch = forward.next();
 768            offset -= ch.len_utf8();
 769            trail_offset = Some(offset);
 770        } else {
 771            break;
 772        }
 773    }
 774
 775    // Find the boundary
 776    let start_offset = offset;
 777    for ch in forward {
 778        if let Some(prev_ch) = prev_ch
 779            && is_boundary(prev_ch, ch)
 780        {
 781            if start_offset == offset {
 782                trail_offset = Some(offset);
 783            } else {
 784                break;
 785            }
 786        }
 787        offset -= ch.len_utf8();
 788        prev_ch = Some(ch);
 789    }
 790
 791    let trail = trail_offset
 792        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Left));
 793
 794    (
 795        trail,
 796        map.clip_point(offset.to_display_point(map), Bias::Left),
 797    )
 798}
 799
 800/// Finds the location of a boundary
 801pub fn find_boundary_trail(
 802    map: &DisplaySnapshot,
 803    head: DisplayPoint,
 804    is_boundary: &mut dyn FnMut(char, char) -> bool,
 805) -> (Option<DisplayPoint>, DisplayPoint) {
 806    let mut offset = head.to_offset(map, Bias::Right);
 807    let mut trail_offset = None;
 808
 809    let mut prev_ch = map.buffer_snapshot().reversed_chars_at(offset).next();
 810    let mut forward = map.buffer_snapshot().chars_at(offset).peekable();
 811
 812    // Skip newlines
 813    while let Some(&ch) = forward.peek() {
 814        if ch == '\n' {
 815            prev_ch = forward.next();
 816            offset += ch.len_utf8();
 817            trail_offset = Some(offset);
 818        } else {
 819            break;
 820        }
 821    }
 822
 823    // Find the boundary
 824    let start_offset = offset;
 825    for ch in forward {
 826        if let Some(prev_ch) = prev_ch
 827            && is_boundary(prev_ch, ch)
 828        {
 829            if start_offset == offset {
 830                trail_offset = Some(offset);
 831            } else {
 832                break;
 833            }
 834        }
 835        offset += ch.len_utf8();
 836        prev_ch = Some(ch);
 837    }
 838
 839    let trail = trail_offset
 840        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Right));
 841
 842    (
 843        trail,
 844        map.clip_point(offset.to_display_point(map), Bias::Right),
 845    )
 846}
 847
 848pub fn find_boundary(
 849    map: &DisplaySnapshot,
 850    from: DisplayPoint,
 851    find_range: FindRange,
 852    is_boundary: &mut dyn FnMut(char, char) -> bool,
 853) -> DisplayPoint {
 854    find_boundary_point(map, from, find_range, is_boundary, false)
 855}
 856
 857pub fn find_boundary_exclusive(
 858    map: &DisplaySnapshot,
 859    from: DisplayPoint,
 860    find_range: FindRange,
 861    is_boundary: &mut dyn FnMut(char, char) -> bool,
 862) -> DisplayPoint {
 863    find_boundary_point(map, from, find_range, is_boundary, true)
 864}
 865
 866/// Returns an iterator over the characters following a given offset in the [`DisplaySnapshot`].
 867/// The returned value also contains a range of the start/end of a returned character in
 868/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 869pub fn chars_after(
 870    map: &DisplaySnapshot,
 871    mut offset: MultiBufferOffset,
 872) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 873    map.buffer_snapshot().chars_at(offset).map(move |ch| {
 874        let before = offset;
 875        offset += ch.len_utf8();
 876        (ch, before..offset)
 877    })
 878}
 879
 880/// Returns a reverse iterator over the characters following a given offset in the [`DisplaySnapshot`].
 881/// The returned value also contains a range of the start/end of a returned character in
 882/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 883pub fn chars_before(
 884    map: &DisplaySnapshot,
 885    mut offset: MultiBufferOffset,
 886) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 887    map.buffer_snapshot()
 888        .reversed_chars_at(offset)
 889        .map(move |ch| {
 890            let after = offset;
 891            offset -= ch.len_utf8();
 892            (ch, offset..after)
 893        })
 894}
 895
 896/// Returns a list of lines (represented as a [`DisplayPoint`] range) contained
 897/// within a passed range.
 898///
 899/// The line ranges are **always* going to be in bounds of a requested range, which means that
 900/// the first and the last lines might not necessarily represent the
 901/// full range of a logical line (as their `.start`/`.end` values are clipped to those of a passed in range).
 902pub fn split_display_range_by_lines(
 903    map: &DisplaySnapshot,
 904    range: Range<DisplayPoint>,
 905) -> Vec<Range<DisplayPoint>> {
 906    let mut result = Vec::new();
 907
 908    let mut start = range.start;
 909    // Loop over all the covered rows until the one containing the range end
 910    for row in range.start.row().0..range.end.row().0 {
 911        let row_end_column = map.line_len(DisplayRow(row));
 912        let end = map.clip_point(
 913            DisplayPoint::new(DisplayRow(row), row_end_column),
 914            Bias::Left,
 915        );
 916        if start != end {
 917            result.push(start..end);
 918        }
 919        start = map.clip_point(DisplayPoint::new(DisplayRow(row + 1), 0), Bias::Left);
 920    }
 921
 922    // Add the final range from the start of the last end to the original range end.
 923    result.push(start..range.end);
 924
 925    result
 926}
 927
 928#[cfg(test)]
 929mod tests {
 930    use super::*;
 931    use crate::{
 932        Buffer, DisplayMap, DisplayRow, FoldPlaceholder, MultiBuffer,
 933        inlays::Inlay,
 934        test::{editor_test_context::EditorTestContext, marked_display_snapshot},
 935    };
 936    use gpui::{AppContext as _, font, px};
 937    use language::Capability;
 938    use multi_buffer::PathKey;
 939    use project::project_settings::DiagnosticSeverity;
 940    use settings::SettingsStore;
 941    use util::post_inc;
 942
 943    #[gpui::test]
 944    fn test_previous_word_start(cx: &mut gpui::App) {
 945        init_test(cx);
 946
 947        fn assert(marked_text: &str, cx: &mut gpui::App) {
 948            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 949            let actual = previous_word_start(&snapshot, display_points[1]);
 950            let expected = display_points[0];
 951            if actual != expected {
 952                eprintln!(
 953                    "previous_word_start mismatch for '{}': actual={:?}, expected={:?}",
 954                    marked_text, actual, expected
 955                );
 956            }
 957            assert_eq!(actual, expected);
 958        }
 959
 960        assert("\nˇ   ˇlorem", cx);
 961        assert("ˇ\nˇ   lorem", cx);
 962        assert("    ˇloremˇ", cx);
 963        assert("ˇ    ˇlorem", cx);
 964        assert("    ˇlorˇem", cx);
 965        assert("\nlorem\nˇ   ˇipsum", cx);
 966        assert("\n\nˇ\nˇ", cx);
 967        assert("    ˇlorem  ˇipsum", cx);
 968        assert("ˇlorem-ˇipsum", cx);
 969        assert("loremˇ-#$@ˇipsum", cx);
 970        assert("ˇlorem_ˇipsum", cx);
 971        assert(" ˇdefγˇ", cx);
 972        assert(" ˇbcΔˇ", cx);
 973        // Test punctuation skipping behavior
 974        assert("ˇhello.ˇ", cx);
 975        assert("helloˇ...ˇ", cx);
 976        assert("helloˇ.---..ˇtest", cx);
 977        assert("test  ˇ.--ˇtest", cx);
 978        assert("oneˇ,;:!?ˇtwo", cx);
 979    }
 980
 981    #[gpui::test]
 982    fn test_previous_subword_start(cx: &mut gpui::App) {
 983        init_test(cx);
 984
 985        fn assert(marked_text: &str, cx: &mut gpui::App) {
 986            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 987            assert_eq!(
 988                previous_subword_start(&snapshot, display_points[1]),
 989                display_points[0]
 990            );
 991        }
 992
 993        // Subword boundaries are respected
 994        assert("loremˇ_ˇipsum", cx);
 995        assert("lorem_ˇipsumˇ", cx);
 996        assert("ˇloremˇ_ipsum", cx);
 997        assert("lorem_ˇipsumˇ_dolor", cx);
 998        assert("loremˇIpˇsum", cx);
 999        assert("loremˇIpsumˇ", cx);
1000
1001        // Word boundaries are still respected
1002        assert("\nˇ   ˇlorem", cx);
1003        assert("    ˇloremˇ", cx);
1004        assert("    ˇlorˇem", cx);
1005        assert("\nlorem\nˇ   ˇipsum", cx);
1006        assert("\n\nˇ\nˇ", cx);
1007        assert("    ˇlorem  ˇipsum", cx);
1008        assert("loremˇ-ˇipsum", cx);
1009        assert("loremˇ-#$@ˇipsum", cx);
1010        assert(" ˇdefγˇ", cx);
1011        assert(" bcˇΔˇ", cx);
1012        assert(" ˇbcδˇ", cx);
1013        assert(" abˇ——ˇcd", cx);
1014    }
1015
1016    #[gpui::test]
1017    fn test_find_preceding_boundary(cx: &mut gpui::App) {
1018        init_test(cx);
1019
1020        fn assert(
1021            marked_text: &str,
1022            cx: &mut gpui::App,
1023            is_boundary: &mut dyn FnMut(char, char) -> bool,
1024        ) {
1025            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1026            assert_eq!(
1027                find_preceding_boundary_display_point(
1028                    &snapshot,
1029                    display_points[1],
1030                    FindRange::MultiLine,
1031                    is_boundary
1032                ),
1033                display_points[0]
1034            );
1035        }
1036
1037        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1038            left == 'c' && right == 'd'
1039        });
1040        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, right| {
1041            left == '\n' && right == 'g'
1042        });
1043        let mut line_count = 0;
1044        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, _| {
1045            if left == '\n' {
1046                line_count += 1;
1047                line_count == 2
1048            } else {
1049                false
1050            }
1051        });
1052    }
1053
1054    #[gpui::test]
1055    fn test_find_preceding_boundary_with_inlays(cx: &mut gpui::App) {
1056        init_test(cx);
1057
1058        let input_text = "abcdefghijklmnopqrstuvwxys";
1059        let font = font("Helvetica");
1060        let font_size = px(14.0);
1061        let buffer = MultiBuffer::build_simple(input_text, cx);
1062        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1063
1064        let display_map = cx.new(|cx| {
1065            DisplayMap::new(
1066                buffer,
1067                font,
1068                font_size,
1069                None,
1070                1,
1071                1,
1072                FoldPlaceholder::test(),
1073                DiagnosticSeverity::Warning,
1074                cx,
1075            )
1076        });
1077
1078        // add all kinds of inlays between two word boundaries: we should be able to cross them all, when looking for another boundary
1079        let mut id = 0;
1080        let inlays = (0..buffer_snapshot.len().0)
1081            .flat_map(|offset| {
1082                let offset = MultiBufferOffset(offset);
1083                [
1084                    Inlay::edit_prediction(
1085                        post_inc(&mut id),
1086                        buffer_snapshot.anchor_before(offset),
1087                        "test",
1088                    ),
1089                    Inlay::edit_prediction(
1090                        post_inc(&mut id),
1091                        buffer_snapshot.anchor_after(offset),
1092                        "test",
1093                    ),
1094                    Inlay::mock_hint(
1095                        post_inc(&mut id),
1096                        buffer_snapshot.anchor_before(offset),
1097                        "test",
1098                    ),
1099                    Inlay::mock_hint(
1100                        post_inc(&mut id),
1101                        buffer_snapshot.anchor_after(offset),
1102                        "test",
1103                    ),
1104                ]
1105            })
1106            .collect();
1107        let snapshot = display_map.update(cx, |map, cx| {
1108            map.splice_inlays(&[], inlays, cx);
1109            map.snapshot(cx)
1110        });
1111
1112        assert_eq!(
1113            find_preceding_boundary_display_point(
1114                &snapshot,
1115                buffer_snapshot.len().to_display_point(&snapshot),
1116                FindRange::MultiLine,
1117                &mut |left, _| left == 'e',
1118            ),
1119            snapshot
1120                .buffer_snapshot()
1121                .offset_to_point(MultiBufferOffset(5))
1122                .to_display_point(&snapshot),
1123            "Should not stop at inlays when looking for boundaries"
1124        );
1125    }
1126
1127    #[gpui::test]
1128    fn test_next_word_end(cx: &mut gpui::App) {
1129        init_test(cx);
1130
1131        fn assert(marked_text: &str, cx: &mut gpui::App) {
1132            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1133            let actual = next_word_end(&snapshot, display_points[0]);
1134            let expected = display_points[1];
1135            if actual != expected {
1136                eprintln!(
1137                    "next_word_end mismatch for '{}': actual={:?}, expected={:?}",
1138                    marked_text, actual, expected
1139                );
1140            }
1141            assert_eq!(actual, expected);
1142        }
1143
1144        assert("\nˇ   loremˇ", cx);
1145        assert("    ˇloremˇ", cx);
1146        assert("    lorˇemˇ", cx);
1147        assert("    loremˇ    ˇ\nipsum\n", cx);
1148        assert("\nˇ\nˇ\n\n", cx);
1149        assert("loremˇ    ipsumˇ   ", cx);
1150        assert("loremˇ-ipsumˇ", cx);
1151        assert("loremˇ#$@-ˇipsum", cx);
1152        assert("loremˇ_ipsumˇ", cx);
1153        assert(" ˇbcΔˇ", cx);
1154        assert(" abˇ——ˇcd", cx);
1155        // Test punctuation skipping behavior
1156        assert("ˇ.helloˇ", cx);
1157        assert("display_pointsˇ[0ˇ]", cx);
1158        assert("ˇ...ˇhello", cx);
1159        assert("helloˇ.---..ˇtest", cx);
1160        assert("testˇ.--ˇ test", cx);
1161        assert("oneˇ,;:!?ˇtwo", cx);
1162    }
1163
1164    #[gpui::test]
1165    fn test_next_subword_end(cx: &mut gpui::App) {
1166        init_test(cx);
1167
1168        fn assert(marked_text: &str, cx: &mut gpui::App) {
1169            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1170            assert_eq!(
1171                next_subword_end(&snapshot, display_points[0]),
1172                display_points[1]
1173            );
1174        }
1175
1176        // Subword boundaries are respected
1177        assert("loremˇ_ˇipsum", cx);
1178        assert("ˇloremˇ_ipsum", cx);
1179        assert("loremˇ_ˇipsum", cx);
1180        assert("lorem_ˇipsumˇ_dolor", cx);
1181        assert("loˇremˇIpsum", cx);
1182        assert("loremˇIpsumˇDolor", cx);
1183
1184        // Word boundaries are still respected
1185        assert("\nˇ   loremˇ", cx);
1186        assert("    ˇloremˇ", cx);
1187        assert("    lorˇemˇ", cx);
1188        assert("    loremˇ    ˇ\nipsum\n", cx);
1189        assert("\nˇ\nˇ\n\n", cx);
1190        assert("loremˇ    ipsumˇ   ", cx);
1191        assert("loremˇ-ˇipsum", cx);
1192        assert("loremˇ#$@-ˇipsum", cx);
1193        assert("loremˇ_ˇipsum", cx);
1194        assert(" ˇbcˇΔ", cx);
1195        assert(" abˇ——ˇcd", cx);
1196    }
1197
1198    #[gpui::test]
1199    fn test_find_boundary(cx: &mut gpui::App) {
1200        init_test(cx);
1201
1202        fn assert(
1203            marked_text: &str,
1204            cx: &mut gpui::App,
1205            is_boundary: &mut dyn FnMut(char, char) -> bool,
1206        ) {
1207            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1208            assert_eq!(
1209                find_boundary(
1210                    &snapshot,
1211                    display_points[0],
1212                    FindRange::MultiLine,
1213                    is_boundary,
1214                ),
1215                display_points[1]
1216            );
1217        }
1218
1219        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1220            left == 'j' && right == 'k'
1221        });
1222        assert("abˇcdef\ngh\nˇijk", cx, &mut |left, right| {
1223            left == '\n' && right == 'i'
1224        });
1225        let mut line_count = 0;
1226        assert("abcˇdef\ngh\nˇijk", cx, &mut |left, _| {
1227            if left == '\n' {
1228                line_count += 1;
1229                line_count == 2
1230            } else {
1231                false
1232            }
1233        });
1234    }
1235
1236    #[gpui::test]
1237    async fn test_move_up_and_down_with_excerpts(cx: &mut gpui::TestAppContext) {
1238        cx.update(|cx| {
1239            init_test(cx);
1240        });
1241
1242        let mut cx = EditorTestContext::new(cx).await;
1243        let editor = cx.editor.clone();
1244        let window = cx.window;
1245        _ = cx.update_window(window, |_, window, cx| {
1246            let text_layout_details =
1247                editor.update(cx, |editor, cx| editor.text_layout_details(window, cx));
1248
1249            let font = font("Helvetica");
1250
1251            let buffer = cx.new(|cx| Buffer::local("abc\ndefg\na\na\na\nhijkl\nmn", cx));
1252            let multibuffer = cx.new(|cx| {
1253                let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
1254                multibuffer.set_excerpts_for_path(
1255                    PathKey::sorted(0),
1256                    buffer.clone(),
1257                    [
1258                        Point::new(0, 0)..Point::new(1, 4),
1259                        Point::new(5, 0)..Point::new(6, 2),
1260                    ],
1261                    0,
1262                    cx,
1263                );
1264                multibuffer
1265            });
1266            let display_map = cx.new(|cx| {
1267                DisplayMap::new(
1268                    multibuffer,
1269                    font,
1270                    px(14.0),
1271                    None,
1272                    0,
1273                    1,
1274                    FoldPlaceholder::test(),
1275                    DiagnosticSeverity::Warning,
1276                    cx,
1277                )
1278            });
1279            let snapshot = display_map.update(cx, |map, cx| map.snapshot(cx));
1280
1281            assert_eq!(snapshot.text(), "abc\ndefg\n\nhijkl\nmn");
1282
1283            let col_2_x = snapshot
1284                .x_for_display_point(DisplayPoint::new(DisplayRow(0), 2), &text_layout_details);
1285
1286            // Can't move up into the first excerpt's header
1287            assert_eq!(
1288                up(
1289                    &snapshot,
1290                    DisplayPoint::new(DisplayRow(0), 2),
1291                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1292                    false,
1293                    &text_layout_details
1294                ),
1295                (
1296                    DisplayPoint::new(DisplayRow(0), 0),
1297                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1298                ),
1299            );
1300            assert_eq!(
1301                up(
1302                    &snapshot,
1303                    DisplayPoint::new(DisplayRow(0), 0),
1304                    SelectionGoal::None,
1305                    false,
1306                    &text_layout_details
1307                ),
1308                (
1309                    DisplayPoint::new(DisplayRow(0), 0),
1310                    SelectionGoal::HorizontalPosition(0.0),
1311                ),
1312            );
1313
1314            let col_4_x = snapshot
1315                .x_for_display_point(DisplayPoint::new(DisplayRow(1), 4), &text_layout_details);
1316
1317            // Move up and down within first excerpt
1318            assert_eq!(
1319                up(
1320                    &snapshot,
1321                    DisplayPoint::new(DisplayRow(1), 4),
1322                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1323                    false,
1324                    &text_layout_details
1325                ),
1326                (
1327                    DisplayPoint::new(DisplayRow(0), 3),
1328                    SelectionGoal::HorizontalPosition(col_4_x.into())
1329                ),
1330            );
1331            assert_eq!(
1332                down(
1333                    &snapshot,
1334                    DisplayPoint::new(DisplayRow(0), 3),
1335                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1336                    false,
1337                    &text_layout_details
1338                ),
1339                (
1340                    DisplayPoint::new(DisplayRow(1), 4),
1341                    SelectionGoal::HorizontalPosition(col_4_x.into())
1342                ),
1343            );
1344
1345            let col_5_x = snapshot
1346                .x_for_display_point(DisplayPoint::new(DisplayRow(3), 5), &text_layout_details);
1347
1348            // Move up and down across second excerpt's header
1349            assert_eq!(
1350                up(
1351                    &snapshot,
1352                    DisplayPoint::new(DisplayRow(3), 5),
1353                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1354                    false,
1355                    &text_layout_details
1356                ),
1357                (
1358                    DisplayPoint::new(DisplayRow(1), 4),
1359                    SelectionGoal::HorizontalPosition(col_5_x.into())
1360                ),
1361            );
1362            assert_eq!(
1363                down(
1364                    &snapshot,
1365                    DisplayPoint::new(DisplayRow(1), 4),
1366                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1367                    false,
1368                    &text_layout_details
1369                ),
1370                (
1371                    DisplayPoint::new(DisplayRow(3), 5),
1372                    SelectionGoal::HorizontalPosition(col_5_x.into())
1373                ),
1374            );
1375
1376            let max_point_x = snapshot
1377                .x_for_display_point(DisplayPoint::new(DisplayRow(4), 2), &text_layout_details);
1378
1379            // Can't move down off the end, and attempting to do so leaves the selection goal unchanged
1380            assert_eq!(
1381                down(
1382                    &snapshot,
1383                    DisplayPoint::new(DisplayRow(4), 0),
1384                    SelectionGoal::HorizontalPosition(0.0),
1385                    false,
1386                    &text_layout_details
1387                ),
1388                (
1389                    DisplayPoint::new(DisplayRow(4), 2),
1390                    SelectionGoal::HorizontalPosition(0.0)
1391                ),
1392            );
1393            assert_eq!(
1394                down(
1395                    &snapshot,
1396                    DisplayPoint::new(DisplayRow(4), 2),
1397                    SelectionGoal::HorizontalPosition(max_point_x.into()),
1398                    false,
1399                    &text_layout_details
1400                ),
1401                (
1402                    DisplayPoint::new(DisplayRow(4), 2),
1403                    SelectionGoal::HorizontalPosition(max_point_x.into())
1404                ),
1405            );
1406        });
1407    }
1408
1409    fn init_test(cx: &mut gpui::App) {
1410        let settings_store = SettingsStore::test(cx);
1411        cx.set_global(settings_store);
1412        theme_settings::init(theme::LoadThemes::JustBase, cx);
1413        crate::init(cx);
1414    }
1415}