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'
 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.is_lowercase() && right.is_uppercase();
 435    is_word_start || is_subword_start
 436}
 437
 438/// Returns a position of the next word boundary, where a word character is defined as either
 439/// uppercase letter, lowercase letter, '_' character or language-specific word character (like '-' in CSS).
 440pub fn next_word_end(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 441    let raw_point = point.to_point(map);
 442    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 443    let mut is_first_iteration = true;
 444    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 445        // Make alt-right skip punctuation to respect VSCode behaviour. For example: |.hello goes to .hello|
 446        if is_first_iteration
 447            && classifier.is_punctuation(left)
 448            && !classifier.is_punctuation(right)
 449            && right != '\n'
 450        {
 451            is_first_iteration = false;
 452            return false;
 453        }
 454        is_first_iteration = false;
 455
 456        (classifier.kind(left) != classifier.kind(right) && !classifier.is_whitespace(left))
 457            || right == '\n'
 458    })
 459}
 460
 461/// Returns a position of the next word boundary, where a word character is defined as either
 462/// uppercase letter, lowercase letter, '_' character, language-specific word character (like '-' in CSS) or newline.
 463pub fn next_word_end_or_newline(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 464    let raw_point = point.to_point(map);
 465    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 466
 467    let mut on_starting_row = true;
 468    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 469        if left == '\n' {
 470            on_starting_row = false;
 471        }
 472        (classifier.kind(left) != classifier.kind(right)
 473            && ((on_starting_row && !left.is_whitespace())
 474                || (!on_starting_row && !right.is_whitespace())))
 475            || right == '\n'
 476    })
 477}
 478
 479/// Returns a position of the next subword boundary, where a subword is defined as a run of
 480/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 481/// lowerspace characters and uppercase characters.
 482pub fn next_subword_end(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 483    let raw_point = point.to_point(map);
 484    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 485
 486    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 487        is_subword_end(left, right, &classifier) || right == '\n'
 488    })
 489}
 490
 491/// Returns a position of the next subword boundary, where a subword is defined as a run of
 492/// word characters of the same "subkind" - where subcharacter kinds are '_' character,
 493/// lowerspace characters and uppercase characters or newline.
 494pub fn next_subword_end_or_newline(map: &DisplaySnapshot, point: DisplayPoint) -> DisplayPoint {
 495    let raw_point = point.to_point(map);
 496    let classifier = map.buffer_snapshot().char_classifier_at(raw_point);
 497
 498    let mut on_starting_row = true;
 499    find_boundary(map, point, FindRange::MultiLine, &mut |left, right| {
 500        if left == '\n' {
 501            on_starting_row = false;
 502        }
 503        ((classifier.kind(left) != classifier.kind(right)
 504            || is_subword_boundary_end(left, right, &classifier))
 505            && ((on_starting_row && !left.is_whitespace())
 506                || (!on_starting_row && !right.is_whitespace())))
 507            || right == '\n'
 508    })
 509}
 510
 511pub fn is_subword_end(left: char, right: char, classifier: &CharClassifier) -> bool {
 512    let is_word_end =
 513        (classifier.kind(left) != classifier.kind(right)) && !classifier.is_whitespace(left);
 514    is_word_end || is_subword_boundary_end(left, right, classifier)
 515}
 516
 517/// Returns true if the transition from `left` to `right` is a subword boundary,
 518/// such as case changes, underscores, or dashes. Does not include word boundaries like whitespace.
 519fn is_subword_boundary_end(left: char, right: char, classifier: &CharClassifier) -> bool {
 520    classifier.is_word('-') && left != '-' && right == '-'
 521        || left != '_' && right == '_'
 522        || left.is_lowercase() && right.is_uppercase()
 523}
 524
 525/// Returns a position of the start of the current paragraph, where a paragraph
 526/// is defined as a run of non-blank lines.
 527pub fn start_of_paragraph(
 528    map: &DisplaySnapshot,
 529    display_point: DisplayPoint,
 530    mut count: usize,
 531) -> DisplayPoint {
 532    let point = display_point.to_point(map);
 533    if point.row == 0 {
 534        return DisplayPoint::zero();
 535    }
 536
 537    let mut found_non_blank_line = false;
 538    for row in (0..point.row + 1).rev() {
 539        let blank = map.buffer_snapshot().is_line_blank(MultiBufferRow(row));
 540        if found_non_blank_line && blank {
 541            if count <= 1 {
 542                return Point::new(row, 0).to_display_point(map);
 543            }
 544            count -= 1;
 545            found_non_blank_line = false;
 546        }
 547
 548        found_non_blank_line |= !blank;
 549    }
 550
 551    DisplayPoint::zero()
 552}
 553
 554/// Returns a position of the end of the current paragraph, where a paragraph
 555/// is defined as a run of non-blank lines.
 556pub fn end_of_paragraph(
 557    map: &DisplaySnapshot,
 558    display_point: DisplayPoint,
 559    mut count: usize,
 560) -> DisplayPoint {
 561    let point = display_point.to_point(map);
 562    if point.row == map.buffer_snapshot().max_row().0 {
 563        return map.max_point();
 564    }
 565
 566    let mut found_non_blank_line = false;
 567    for row in point.row..=map.buffer_snapshot().max_row().0 {
 568        let blank = map.buffer_snapshot().is_line_blank(MultiBufferRow(row));
 569        if found_non_blank_line && blank {
 570            if count <= 1 {
 571                return Point::new(row, 0).to_display_point(map);
 572            }
 573            count -= 1;
 574            found_non_blank_line = false;
 575        }
 576
 577        found_non_blank_line |= !blank;
 578    }
 579
 580    map.max_point()
 581}
 582
 583pub fn start_of_excerpt(
 584    map: &DisplaySnapshot,
 585    display_point: DisplayPoint,
 586    direction: Direction,
 587) -> DisplayPoint {
 588    let point = map.display_point_to_point(display_point, Bias::Left);
 589    let Some(excerpt) = map.buffer_snapshot().excerpt_containing(point..point) else {
 590        return display_point;
 591    };
 592    match direction {
 593        Direction::Prev => {
 594            let mut start = excerpt.start_anchor().to_display_point(map);
 595            if start >= display_point && start.row() > DisplayRow(0) {
 596                let Some(excerpt) = map.buffer_snapshot().excerpt_before(excerpt.id()) else {
 597                    return display_point;
 598                };
 599                start = excerpt.start_anchor().to_display_point(map);
 600            }
 601            start
 602        }
 603        Direction::Next => {
 604            let mut end = excerpt.end_anchor().to_display_point(map);
 605            *end.row_mut() += 1;
 606            map.clip_point(end, Bias::Right)
 607        }
 608    }
 609}
 610
 611pub fn end_of_excerpt(
 612    map: &DisplaySnapshot,
 613    display_point: DisplayPoint,
 614    direction: Direction,
 615) -> DisplayPoint {
 616    let point = map.display_point_to_point(display_point, Bias::Left);
 617    let Some(excerpt) = map.buffer_snapshot().excerpt_containing(point..point) else {
 618        return display_point;
 619    };
 620    match direction {
 621        Direction::Prev => {
 622            let mut start = excerpt.start_anchor().to_display_point(map);
 623            if start.row() > DisplayRow(0) {
 624                *start.row_mut() -= 1;
 625            }
 626            start = map.clip_point(start, Bias::Left);
 627            *start.column_mut() = 0;
 628            start
 629        }
 630        Direction::Next => {
 631            let mut end = excerpt.end_anchor().to_display_point(map);
 632            *end.column_mut() = 0;
 633            if end <= display_point {
 634                *end.row_mut() += 1;
 635                let point_end = map.display_point_to_point(end, Bias::Right);
 636                let Some(excerpt) = map
 637                    .buffer_snapshot()
 638                    .excerpt_containing(point_end..point_end)
 639                else {
 640                    return display_point;
 641                };
 642                end = excerpt.end_anchor().to_display_point(map);
 643                *end.column_mut() = 0;
 644            }
 645            end
 646        }
 647    }
 648}
 649
 650/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 651/// indicated by the given predicate returning true.
 652/// The predicate is called with the character to the left and right of the candidate boundary location.
 653/// 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.
 654pub fn find_preceding_boundary_point(
 655    buffer_snapshot: &MultiBufferSnapshot,
 656    from: Point,
 657    find_range: FindRange,
 658    is_boundary: &mut dyn FnMut(char, char) -> bool,
 659) -> Point {
 660    let mut prev_ch = None;
 661    let mut offset = from.to_offset(buffer_snapshot);
 662
 663    for ch in buffer_snapshot.reversed_chars_at(offset) {
 664        if find_range == FindRange::SingleLine && ch == '\n' {
 665            break;
 666        }
 667        if let Some(prev_ch) = prev_ch
 668            && is_boundary(ch, prev_ch)
 669        {
 670            break;
 671        }
 672
 673        offset -= ch.len_utf8();
 674        prev_ch = Some(ch);
 675    }
 676
 677    offset.to_point(buffer_snapshot)
 678}
 679
 680/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 681/// indicated by the given predicate returning true.
 682/// The predicate is called with the character to the left and right of the candidate boundary location.
 683/// 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.
 684pub fn find_preceding_boundary_display_point(
 685    map: &DisplaySnapshot,
 686    from: DisplayPoint,
 687    find_range: FindRange,
 688    is_boundary: &mut dyn FnMut(char, char) -> bool,
 689) -> DisplayPoint {
 690    let result = find_preceding_boundary_point(
 691        map.buffer_snapshot(),
 692        from.to_point(map),
 693        find_range,
 694        is_boundary,
 695    );
 696    map.clip_point(result.to_display_point(map), Bias::Left)
 697}
 698
 699/// Scans for a boundary following the given start point until a boundary is found, indicated by the
 700/// given predicate returning true. The predicate is called with the character to the left and right
 701/// of the candidate boundary location, and will be called with `\n` characters indicating the start
 702/// or end of a line. The function supports optionally returning the point just before the boundary
 703/// is found via return_point_before_boundary.
 704pub fn find_boundary_point(
 705    map: &DisplaySnapshot,
 706    from: DisplayPoint,
 707    find_range: FindRange,
 708    is_boundary: &mut dyn FnMut(char, char) -> bool,
 709    return_point_before_boundary: bool,
 710) -> DisplayPoint {
 711    let mut offset = from.to_offset(map, Bias::Right);
 712    let mut prev_offset = offset;
 713    let mut prev_ch = None;
 714
 715    for ch in map.buffer_snapshot().chars_at(offset) {
 716        if find_range == FindRange::SingleLine && ch == '\n' {
 717            break;
 718        }
 719        if let Some(prev_ch) = prev_ch
 720            && is_boundary(prev_ch, ch)
 721        {
 722            if return_point_before_boundary {
 723                return map.clip_point(prev_offset.to_display_point(map), Bias::Right);
 724            } else {
 725                break;
 726            }
 727        }
 728        prev_offset = offset;
 729        offset += ch.len_utf8();
 730        prev_ch = Some(ch);
 731    }
 732    map.clip_point(offset.to_display_point(map), Bias::Right)
 733}
 734
 735pub fn find_preceding_boundary_trail(
 736    map: &DisplaySnapshot,
 737    head: DisplayPoint,
 738    is_boundary: &mut dyn FnMut(char, char) -> bool,
 739) -> (Option<DisplayPoint>, DisplayPoint) {
 740    let mut offset = head.to_offset(map, Bias::Left);
 741    let mut trail_offset = None;
 742
 743    let mut prev_ch = map.buffer_snapshot().chars_at(offset).next();
 744    let mut forward = map.buffer_snapshot().reversed_chars_at(offset).peekable();
 745
 746    // Skip newlines
 747    while let Some(&ch) = forward.peek() {
 748        if ch == '\n' {
 749            prev_ch = forward.next();
 750            offset -= ch.len_utf8();
 751            trail_offset = Some(offset);
 752        } else {
 753            break;
 754        }
 755    }
 756
 757    // Find the boundary
 758    let start_offset = offset;
 759    for ch in forward {
 760        if let Some(prev_ch) = prev_ch
 761            && is_boundary(prev_ch, ch)
 762        {
 763            if start_offset == offset {
 764                trail_offset = Some(offset);
 765            } else {
 766                break;
 767            }
 768        }
 769        offset -= ch.len_utf8();
 770        prev_ch = Some(ch);
 771    }
 772
 773    let trail = trail_offset
 774        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Left));
 775
 776    (
 777        trail,
 778        map.clip_point(offset.to_display_point(map), Bias::Left),
 779    )
 780}
 781
 782/// Finds the location of a boundary
 783pub fn find_boundary_trail(
 784    map: &DisplaySnapshot,
 785    head: DisplayPoint,
 786    is_boundary: &mut dyn FnMut(char, char) -> bool,
 787) -> (Option<DisplayPoint>, DisplayPoint) {
 788    let mut offset = head.to_offset(map, Bias::Right);
 789    let mut trail_offset = None;
 790
 791    let mut prev_ch = map.buffer_snapshot().reversed_chars_at(offset).next();
 792    let mut forward = map.buffer_snapshot().chars_at(offset).peekable();
 793
 794    // Skip newlines
 795    while let Some(&ch) = forward.peek() {
 796        if ch == '\n' {
 797            prev_ch = forward.next();
 798            offset += ch.len_utf8();
 799            trail_offset = Some(offset);
 800        } else {
 801            break;
 802        }
 803    }
 804
 805    // Find the boundary
 806    let start_offset = offset;
 807    for ch in forward {
 808        if let Some(prev_ch) = prev_ch
 809            && is_boundary(prev_ch, ch)
 810        {
 811            if start_offset == offset {
 812                trail_offset = Some(offset);
 813            } else {
 814                break;
 815            }
 816        }
 817        offset += ch.len_utf8();
 818        prev_ch = Some(ch);
 819    }
 820
 821    let trail = trail_offset
 822        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Right));
 823
 824    (
 825        trail,
 826        map.clip_point(offset.to_display_point(map), Bias::Right),
 827    )
 828}
 829
 830pub fn find_boundary(
 831    map: &DisplaySnapshot,
 832    from: DisplayPoint,
 833    find_range: FindRange,
 834    is_boundary: &mut dyn FnMut(char, char) -> bool,
 835) -> DisplayPoint {
 836    find_boundary_point(map, from, find_range, is_boundary, false)
 837}
 838
 839pub fn find_boundary_exclusive(
 840    map: &DisplaySnapshot,
 841    from: DisplayPoint,
 842    find_range: FindRange,
 843    is_boundary: &mut dyn FnMut(char, char) -> bool,
 844) -> DisplayPoint {
 845    find_boundary_point(map, from, find_range, is_boundary, true)
 846}
 847
 848/// Returns an iterator over the characters following a given offset in the [`DisplaySnapshot`].
 849/// The returned value also contains a range of the start/end of a returned character in
 850/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 851pub fn chars_after(
 852    map: &DisplaySnapshot,
 853    mut offset: MultiBufferOffset,
 854) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 855    map.buffer_snapshot().chars_at(offset).map(move |ch| {
 856        let before = offset;
 857        offset += ch.len_utf8();
 858        (ch, before..offset)
 859    })
 860}
 861
 862/// Returns a reverse iterator over the characters following a given offset in the [`DisplaySnapshot`].
 863/// The returned value also contains a range of the start/end of a returned character in
 864/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 865pub fn chars_before(
 866    map: &DisplaySnapshot,
 867    mut offset: MultiBufferOffset,
 868) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 869    map.buffer_snapshot()
 870        .reversed_chars_at(offset)
 871        .map(move |ch| {
 872            let after = offset;
 873            offset -= ch.len_utf8();
 874            (ch, offset..after)
 875        })
 876}
 877
 878/// Returns a list of lines (represented as a [`DisplayPoint`] range) contained
 879/// within a passed range.
 880///
 881/// The line ranges are **always* going to be in bounds of a requested range, which means that
 882/// the first and the last lines might not necessarily represent the
 883/// full range of a logical line (as their `.start`/`.end` values are clipped to those of a passed in range).
 884pub fn split_display_range_by_lines(
 885    map: &DisplaySnapshot,
 886    range: Range<DisplayPoint>,
 887) -> Vec<Range<DisplayPoint>> {
 888    let mut result = Vec::new();
 889
 890    let mut start = range.start;
 891    // Loop over all the covered rows until the one containing the range end
 892    for row in range.start.row().0..range.end.row().0 {
 893        let row_end_column = map.line_len(DisplayRow(row));
 894        let end = map.clip_point(
 895            DisplayPoint::new(DisplayRow(row), row_end_column),
 896            Bias::Left,
 897        );
 898        if start != end {
 899            result.push(start..end);
 900        }
 901        start = map.clip_point(DisplayPoint::new(DisplayRow(row + 1), 0), Bias::Left);
 902    }
 903
 904    // Add the final range from the start of the last end to the original range end.
 905    result.push(start..range.end);
 906
 907    result
 908}
 909
 910#[cfg(test)]
 911mod tests {
 912    use super::*;
 913    use crate::{
 914        Buffer, DisplayMap, DisplayRow, FoldPlaceholder, MultiBuffer,
 915        inlays::Inlay,
 916        test::{editor_test_context::EditorTestContext, marked_display_snapshot},
 917    };
 918    use gpui::{AppContext as _, font, px};
 919    use language::Capability;
 920    use multi_buffer::PathKey;
 921    use project::project_settings::DiagnosticSeverity;
 922    use settings::SettingsStore;
 923    use util::post_inc;
 924
 925    #[gpui::test]
 926    fn test_previous_word_start(cx: &mut gpui::App) {
 927        init_test(cx);
 928
 929        fn assert(marked_text: &str, cx: &mut gpui::App) {
 930            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 931            let actual = previous_word_start(&snapshot, display_points[1]);
 932            let expected = display_points[0];
 933            if actual != expected {
 934                eprintln!(
 935                    "previous_word_start mismatch for '{}': actual={:?}, expected={:?}",
 936                    marked_text, actual, expected
 937                );
 938            }
 939            assert_eq!(actual, expected);
 940        }
 941
 942        assert("\nˇ   ˇlorem", cx);
 943        assert("ˇ\nˇ   lorem", cx);
 944        assert("    ˇloremˇ", cx);
 945        assert("ˇ    ˇlorem", cx);
 946        assert("    ˇlorˇem", cx);
 947        assert("\nlorem\nˇ   ˇipsum", cx);
 948        assert("\n\nˇ\nˇ", cx);
 949        assert("    ˇlorem  ˇipsum", cx);
 950        assert("ˇlorem-ˇipsum", cx);
 951        assert("loremˇ-#$@ˇipsum", cx);
 952        assert("ˇlorem_ˇipsum", cx);
 953        assert(" ˇdefγˇ", cx);
 954        assert(" ˇbcΔˇ", cx);
 955        // Test punctuation skipping behavior
 956        assert("ˇhello.ˇ", cx);
 957        assert("helloˇ...ˇ", cx);
 958        assert("helloˇ.---..ˇtest", cx);
 959        assert("test  ˇ.--ˇtest", cx);
 960        assert("oneˇ,;:!?ˇtwo", cx);
 961    }
 962
 963    #[gpui::test]
 964    fn test_previous_subword_start(cx: &mut gpui::App) {
 965        init_test(cx);
 966
 967        fn assert(marked_text: &str, cx: &mut gpui::App) {
 968            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 969            assert_eq!(
 970                previous_subword_start(&snapshot, display_points[1]),
 971                display_points[0]
 972            );
 973        }
 974
 975        // Subword boundaries are respected
 976        assert("lorem_ˇipˇsum", cx);
 977        assert("lorem_ˇipsumˇ", cx);
 978        assert("ˇlorem_ˇipsum", cx);
 979        assert("lorem_ˇipsum_ˇdolor", cx);
 980        assert("loremˇIpˇsum", cx);
 981        assert("loremˇIpsumˇ", cx);
 982
 983        // Word boundaries are still respected
 984        assert("\nˇ   ˇlorem", cx);
 985        assert("    ˇloremˇ", cx);
 986        assert("    ˇlorˇem", cx);
 987        assert("\nlorem\nˇ   ˇipsum", cx);
 988        assert("\n\nˇ\nˇ", cx);
 989        assert("    ˇlorem  ˇipsum", cx);
 990        assert("loremˇ-ˇipsum", cx);
 991        assert("loremˇ-#$@ˇipsum", cx);
 992        assert(" ˇdefγˇ", cx);
 993        assert(" bcˇΔˇ", cx);
 994        assert(" ˇbcδˇ", cx);
 995        assert(" abˇ——ˇcd", cx);
 996    }
 997
 998    #[gpui::test]
 999    fn test_find_preceding_boundary(cx: &mut gpui::App) {
1000        init_test(cx);
1001
1002        fn assert(
1003            marked_text: &str,
1004            cx: &mut gpui::App,
1005            is_boundary: &mut dyn FnMut(char, char) -> bool,
1006        ) {
1007            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1008            assert_eq!(
1009                find_preceding_boundary_display_point(
1010                    &snapshot,
1011                    display_points[1],
1012                    FindRange::MultiLine,
1013                    is_boundary
1014                ),
1015                display_points[0]
1016            );
1017        }
1018
1019        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1020            left == 'c' && right == 'd'
1021        });
1022        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, right| {
1023            left == '\n' && right == 'g'
1024        });
1025        let mut line_count = 0;
1026        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, _| {
1027            if left == '\n' {
1028                line_count += 1;
1029                line_count == 2
1030            } else {
1031                false
1032            }
1033        });
1034    }
1035
1036    #[gpui::test]
1037    fn test_find_preceding_boundary_with_inlays(cx: &mut gpui::App) {
1038        init_test(cx);
1039
1040        let input_text = "abcdefghijklmnopqrstuvwxys";
1041        let font = font("Helvetica");
1042        let font_size = px(14.0);
1043        let buffer = MultiBuffer::build_simple(input_text, cx);
1044        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1045
1046        let display_map = cx.new(|cx| {
1047            DisplayMap::new(
1048                buffer,
1049                font,
1050                font_size,
1051                None,
1052                1,
1053                1,
1054                FoldPlaceholder::test(),
1055                DiagnosticSeverity::Warning,
1056                cx,
1057            )
1058        });
1059
1060        // add all kinds of inlays between two word boundaries: we should be able to cross them all, when looking for another boundary
1061        let mut id = 0;
1062        let inlays = (0..buffer_snapshot.len().0)
1063            .flat_map(|offset| {
1064                let offset = MultiBufferOffset(offset);
1065                [
1066                    Inlay::edit_prediction(
1067                        post_inc(&mut id),
1068                        buffer_snapshot.anchor_before(offset),
1069                        "test",
1070                    ),
1071                    Inlay::edit_prediction(
1072                        post_inc(&mut id),
1073                        buffer_snapshot.anchor_after(offset),
1074                        "test",
1075                    ),
1076                    Inlay::mock_hint(
1077                        post_inc(&mut id),
1078                        buffer_snapshot.anchor_before(offset),
1079                        "test",
1080                    ),
1081                    Inlay::mock_hint(
1082                        post_inc(&mut id),
1083                        buffer_snapshot.anchor_after(offset),
1084                        "test",
1085                    ),
1086                ]
1087            })
1088            .collect();
1089        let snapshot = display_map.update(cx, |map, cx| {
1090            map.splice_inlays(&[], inlays, cx);
1091            map.snapshot(cx)
1092        });
1093
1094        assert_eq!(
1095            find_preceding_boundary_display_point(
1096                &snapshot,
1097                buffer_snapshot.len().to_display_point(&snapshot),
1098                FindRange::MultiLine,
1099                &mut |left, _| left == 'e',
1100            ),
1101            snapshot
1102                .buffer_snapshot()
1103                .offset_to_point(MultiBufferOffset(5))
1104                .to_display_point(&snapshot),
1105            "Should not stop at inlays when looking for boundaries"
1106        );
1107    }
1108
1109    #[gpui::test]
1110    fn test_next_word_end(cx: &mut gpui::App) {
1111        init_test(cx);
1112
1113        fn assert(marked_text: &str, cx: &mut gpui::App) {
1114            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1115            let actual = next_word_end(&snapshot, display_points[0]);
1116            let expected = display_points[1];
1117            if actual != expected {
1118                eprintln!(
1119                    "next_word_end mismatch for '{}': actual={:?}, expected={:?}",
1120                    marked_text, actual, expected
1121                );
1122            }
1123            assert_eq!(actual, expected);
1124        }
1125
1126        assert("\nˇ   loremˇ", cx);
1127        assert("    ˇloremˇ", cx);
1128        assert("    lorˇemˇ", cx);
1129        assert("    loremˇ    ˇ\nipsum\n", cx);
1130        assert("\nˇ\nˇ\n\n", cx);
1131        assert("loremˇ    ipsumˇ   ", cx);
1132        assert("loremˇ-ipsumˇ", cx);
1133        assert("loremˇ#$@-ˇipsum", cx);
1134        assert("loremˇ_ipsumˇ", cx);
1135        assert(" ˇbcΔˇ", cx);
1136        assert(" abˇ——ˇcd", cx);
1137        // Test punctuation skipping behavior
1138        assert("ˇ.helloˇ", cx);
1139        assert("display_pointsˇ[0ˇ]", cx);
1140        assert("ˇ...ˇhello", cx);
1141        assert("helloˇ.---..ˇtest", cx);
1142        assert("testˇ.--ˇ test", cx);
1143        assert("oneˇ,;:!?ˇtwo", cx);
1144    }
1145
1146    #[gpui::test]
1147    fn test_next_subword_end(cx: &mut gpui::App) {
1148        init_test(cx);
1149
1150        fn assert(marked_text: &str, cx: &mut gpui::App) {
1151            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1152            assert_eq!(
1153                next_subword_end(&snapshot, display_points[0]),
1154                display_points[1]
1155            );
1156        }
1157
1158        // Subword boundaries are respected
1159        assert("loˇremˇ_ipsum", cx);
1160        assert("ˇloremˇ_ipsum", cx);
1161        assert("loremˇ_ipsumˇ", cx);
1162        assert("loremˇ_ipsumˇ_dolor", cx);
1163        assert("loˇremˇIpsum", cx);
1164        assert("loremˇIpsumˇDolor", cx);
1165
1166        // Word boundaries are still respected
1167        assert("\nˇ   loremˇ", cx);
1168        assert("    ˇloremˇ", cx);
1169        assert("    lorˇemˇ", cx);
1170        assert("    loremˇ    ˇ\nipsum\n", cx);
1171        assert("\nˇ\nˇ\n\n", cx);
1172        assert("loremˇ    ipsumˇ   ", cx);
1173        assert("loremˇ-ˇipsum", cx);
1174        assert("loremˇ#$@-ˇipsum", cx);
1175        assert("loremˇ_ipsumˇ", cx);
1176        assert(" ˇbcˇΔ", cx);
1177        assert(" abˇ——ˇcd", cx);
1178    }
1179
1180    #[gpui::test]
1181    fn test_find_boundary(cx: &mut gpui::App) {
1182        init_test(cx);
1183
1184        fn assert(
1185            marked_text: &str,
1186            cx: &mut gpui::App,
1187            is_boundary: &mut dyn FnMut(char, char) -> bool,
1188        ) {
1189            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1190            assert_eq!(
1191                find_boundary(
1192                    &snapshot,
1193                    display_points[0],
1194                    FindRange::MultiLine,
1195                    is_boundary,
1196                ),
1197                display_points[1]
1198            );
1199        }
1200
1201        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1202            left == 'j' && right == 'k'
1203        });
1204        assert("abˇcdef\ngh\nˇijk", cx, &mut |left, right| {
1205            left == '\n' && right == 'i'
1206        });
1207        let mut line_count = 0;
1208        assert("abcˇdef\ngh\nˇijk", cx, &mut |left, _| {
1209            if left == '\n' {
1210                line_count += 1;
1211                line_count == 2
1212            } else {
1213                false
1214            }
1215        });
1216    }
1217
1218    #[gpui::test]
1219    async fn test_move_up_and_down_with_excerpts(cx: &mut gpui::TestAppContext) {
1220        cx.update(|cx| {
1221            init_test(cx);
1222        });
1223
1224        let mut cx = EditorTestContext::new(cx).await;
1225        let editor = cx.editor.clone();
1226        let window = cx.window;
1227        _ = cx.update_window(window, |_, window, cx| {
1228            let text_layout_details =
1229                editor.update(cx, |editor, cx| editor.text_layout_details(window, cx));
1230
1231            let font = font("Helvetica");
1232
1233            let buffer = cx.new(|cx| Buffer::local("abc\ndefg\na\na\na\nhijkl\nmn", cx));
1234            let multibuffer = cx.new(|cx| {
1235                let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
1236                multibuffer.set_excerpts_for_path(
1237                    PathKey::sorted(0),
1238                    buffer.clone(),
1239                    [
1240                        Point::new(0, 0)..Point::new(1, 4),
1241                        Point::new(5, 0)..Point::new(6, 2),
1242                    ],
1243                    0,
1244                    cx,
1245                );
1246                multibuffer
1247            });
1248            let display_map = cx.new(|cx| {
1249                DisplayMap::new(
1250                    multibuffer,
1251                    font,
1252                    px(14.0),
1253                    None,
1254                    0,
1255                    1,
1256                    FoldPlaceholder::test(),
1257                    DiagnosticSeverity::Warning,
1258                    cx,
1259                )
1260            });
1261            let snapshot = display_map.update(cx, |map, cx| map.snapshot(cx));
1262
1263            assert_eq!(snapshot.text(), "abc\ndefg\n\nhijkl\nmn");
1264
1265            let col_2_x = snapshot
1266                .x_for_display_point(DisplayPoint::new(DisplayRow(0), 2), &text_layout_details);
1267
1268            // Can't move up into the first excerpt's header
1269            assert_eq!(
1270                up(
1271                    &snapshot,
1272                    DisplayPoint::new(DisplayRow(0), 2),
1273                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1274                    false,
1275                    &text_layout_details
1276                ),
1277                (
1278                    DisplayPoint::new(DisplayRow(0), 0),
1279                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1280                ),
1281            );
1282            assert_eq!(
1283                up(
1284                    &snapshot,
1285                    DisplayPoint::new(DisplayRow(0), 0),
1286                    SelectionGoal::None,
1287                    false,
1288                    &text_layout_details
1289                ),
1290                (
1291                    DisplayPoint::new(DisplayRow(0), 0),
1292                    SelectionGoal::HorizontalPosition(0.0),
1293                ),
1294            );
1295
1296            let col_4_x = snapshot
1297                .x_for_display_point(DisplayPoint::new(DisplayRow(1), 4), &text_layout_details);
1298
1299            // Move up and down within first excerpt
1300            assert_eq!(
1301                up(
1302                    &snapshot,
1303                    DisplayPoint::new(DisplayRow(1), 4),
1304                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1305                    false,
1306                    &text_layout_details
1307                ),
1308                (
1309                    DisplayPoint::new(DisplayRow(0), 3),
1310                    SelectionGoal::HorizontalPosition(col_4_x.into())
1311                ),
1312            );
1313            assert_eq!(
1314                down(
1315                    &snapshot,
1316                    DisplayPoint::new(DisplayRow(0), 3),
1317                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1318                    false,
1319                    &text_layout_details
1320                ),
1321                (
1322                    DisplayPoint::new(DisplayRow(1), 4),
1323                    SelectionGoal::HorizontalPosition(col_4_x.into())
1324                ),
1325            );
1326
1327            let col_5_x = snapshot
1328                .x_for_display_point(DisplayPoint::new(DisplayRow(3), 5), &text_layout_details);
1329
1330            // Move up and down across second excerpt's header
1331            assert_eq!(
1332                up(
1333                    &snapshot,
1334                    DisplayPoint::new(DisplayRow(3), 5),
1335                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1336                    false,
1337                    &text_layout_details
1338                ),
1339                (
1340                    DisplayPoint::new(DisplayRow(1), 4),
1341                    SelectionGoal::HorizontalPosition(col_5_x.into())
1342                ),
1343            );
1344            assert_eq!(
1345                down(
1346                    &snapshot,
1347                    DisplayPoint::new(DisplayRow(1), 4),
1348                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1349                    false,
1350                    &text_layout_details
1351                ),
1352                (
1353                    DisplayPoint::new(DisplayRow(3), 5),
1354                    SelectionGoal::HorizontalPosition(col_5_x.into())
1355                ),
1356            );
1357
1358            let max_point_x = snapshot
1359                .x_for_display_point(DisplayPoint::new(DisplayRow(4), 2), &text_layout_details);
1360
1361            // Can't move down off the end, and attempting to do so leaves the selection goal unchanged
1362            assert_eq!(
1363                down(
1364                    &snapshot,
1365                    DisplayPoint::new(DisplayRow(4), 0),
1366                    SelectionGoal::HorizontalPosition(0.0),
1367                    false,
1368                    &text_layout_details
1369                ),
1370                (
1371                    DisplayPoint::new(DisplayRow(4), 2),
1372                    SelectionGoal::HorizontalPosition(0.0)
1373                ),
1374            );
1375            assert_eq!(
1376                down(
1377                    &snapshot,
1378                    DisplayPoint::new(DisplayRow(4), 2),
1379                    SelectionGoal::HorizontalPosition(max_point_x.into()),
1380                    false,
1381                    &text_layout_details
1382                ),
1383                (
1384                    DisplayPoint::new(DisplayRow(4), 2),
1385                    SelectionGoal::HorizontalPosition(max_point_x.into())
1386                ),
1387            );
1388        });
1389    }
1390
1391    fn init_test(cx: &mut gpui::App) {
1392        let settings_store = SettingsStore::test(cx);
1393        cx.set_global(settings_store);
1394        theme::init(theme::LoadThemes::JustBase, cx);
1395        crate::init(cx);
1396    }
1397}