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) = map.buffer_snapshot().excerpt_containing(point..point) else {
 592        return display_point;
 593    };
 594    match direction {
 595        Direction::Prev => {
 596            let mut start = excerpt.start_anchor().to_display_point(map);
 597            if start >= display_point && start.row() > DisplayRow(0) {
 598                let Some(excerpt) = map.buffer_snapshot().excerpt_before(excerpt.id()) else {
 599                    return display_point;
 600                };
 601                start = excerpt.start_anchor().to_display_point(map);
 602            }
 603            start
 604        }
 605        Direction::Next => {
 606            let mut end = excerpt.end_anchor().to_display_point(map);
 607            *end.row_mut() += 1;
 608            map.clip_point(end, Bias::Right)
 609        }
 610    }
 611}
 612
 613pub fn end_of_excerpt(
 614    map: &DisplaySnapshot,
 615    display_point: DisplayPoint,
 616    direction: Direction,
 617) -> DisplayPoint {
 618    let point = map.display_point_to_point(display_point, Bias::Left);
 619    let Some(excerpt) = map.buffer_snapshot().excerpt_containing(point..point) else {
 620        return display_point;
 621    };
 622    match direction {
 623        Direction::Prev => {
 624            let mut start = excerpt.start_anchor().to_display_point(map);
 625            if start.row() > DisplayRow(0) {
 626                *start.row_mut() -= 1;
 627            }
 628            start = map.clip_point(start, Bias::Left);
 629            *start.column_mut() = 0;
 630            start
 631        }
 632        Direction::Next => {
 633            let mut end = excerpt.end_anchor().to_display_point(map);
 634            *end.column_mut() = 0;
 635            if end <= display_point {
 636                *end.row_mut() += 1;
 637                let point_end = map.display_point_to_point(end, Bias::Right);
 638                let Some(excerpt) = map
 639                    .buffer_snapshot()
 640                    .excerpt_containing(point_end..point_end)
 641                else {
 642                    return display_point;
 643                };
 644                end = excerpt.end_anchor().to_display_point(map);
 645                *end.column_mut() = 0;
 646            }
 647            end
 648        }
 649    }
 650}
 651
 652/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 653/// indicated by the given predicate returning true.
 654/// The predicate is called with the character to the left and right of the candidate boundary location.
 655/// 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.
 656pub fn find_preceding_boundary_point(
 657    buffer_snapshot: &MultiBufferSnapshot,
 658    from: Point,
 659    find_range: FindRange,
 660    is_boundary: &mut dyn FnMut(char, char) -> bool,
 661) -> Point {
 662    let mut prev_ch = None;
 663    let mut offset = from.to_offset(buffer_snapshot);
 664
 665    for ch in buffer_snapshot.reversed_chars_at(offset) {
 666        if find_range == FindRange::SingleLine && ch == '\n' {
 667            break;
 668        }
 669        if let Some(prev_ch) = prev_ch
 670            && is_boundary(ch, prev_ch)
 671        {
 672            break;
 673        }
 674
 675        offset -= ch.len_utf8();
 676        prev_ch = Some(ch);
 677    }
 678
 679    offset.to_point(buffer_snapshot)
 680}
 681
 682/// Scans for a boundary preceding the given start point `from` until a boundary is found,
 683/// indicated by the given predicate returning true.
 684/// The predicate is called with the character to the left and right of the candidate boundary location.
 685/// 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.
 686pub fn find_preceding_boundary_display_point(
 687    map: &DisplaySnapshot,
 688    from: DisplayPoint,
 689    find_range: FindRange,
 690    is_boundary: &mut dyn FnMut(char, char) -> bool,
 691) -> DisplayPoint {
 692    let result = find_preceding_boundary_point(
 693        map.buffer_snapshot(),
 694        from.to_point(map),
 695        find_range,
 696        is_boundary,
 697    );
 698    map.clip_point(result.to_display_point(map), Bias::Left)
 699}
 700
 701/// Scans for a boundary following the given start point until a boundary is found, indicated by the
 702/// given predicate returning true. The predicate is called with the character to the left and right
 703/// of the candidate boundary location, and will be called with `\n` characters indicating the start
 704/// or end of a line. The function supports optionally returning the point just before the boundary
 705/// is found via return_point_before_boundary.
 706pub fn find_boundary_point(
 707    map: &DisplaySnapshot,
 708    from: DisplayPoint,
 709    find_range: FindRange,
 710    is_boundary: &mut dyn FnMut(char, char) -> bool,
 711    return_point_before_boundary: bool,
 712) -> DisplayPoint {
 713    let mut offset = from.to_offset(map, Bias::Right);
 714    let mut prev_offset = offset;
 715    let mut prev_ch = None;
 716
 717    for ch in map.buffer_snapshot().chars_at(offset) {
 718        if find_range == FindRange::SingleLine && ch == '\n' {
 719            break;
 720        }
 721        if let Some(prev_ch) = prev_ch
 722            && is_boundary(prev_ch, ch)
 723        {
 724            if return_point_before_boundary {
 725                return map.clip_point(prev_offset.to_display_point(map), Bias::Right);
 726            } else {
 727                break;
 728            }
 729        }
 730        prev_offset = offset;
 731        offset += ch.len_utf8();
 732        prev_ch = Some(ch);
 733    }
 734    map.clip_point(offset.to_display_point(map), Bias::Right)
 735}
 736
 737pub fn find_preceding_boundary_trail(
 738    map: &DisplaySnapshot,
 739    head: DisplayPoint,
 740    is_boundary: &mut dyn FnMut(char, char) -> bool,
 741) -> (Option<DisplayPoint>, DisplayPoint) {
 742    let mut offset = head.to_offset(map, Bias::Left);
 743    let mut trail_offset = None;
 744
 745    let mut prev_ch = map.buffer_snapshot().chars_at(offset).next();
 746    let mut forward = map.buffer_snapshot().reversed_chars_at(offset).peekable();
 747
 748    // Skip newlines
 749    while let Some(&ch) = forward.peek() {
 750        if ch == '\n' {
 751            prev_ch = forward.next();
 752            offset -= ch.len_utf8();
 753            trail_offset = Some(offset);
 754        } else {
 755            break;
 756        }
 757    }
 758
 759    // Find the boundary
 760    let start_offset = offset;
 761    for ch in forward {
 762        if let Some(prev_ch) = prev_ch
 763            && is_boundary(prev_ch, ch)
 764        {
 765            if start_offset == offset {
 766                trail_offset = Some(offset);
 767            } else {
 768                break;
 769            }
 770        }
 771        offset -= ch.len_utf8();
 772        prev_ch = Some(ch);
 773    }
 774
 775    let trail = trail_offset
 776        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Left));
 777
 778    (
 779        trail,
 780        map.clip_point(offset.to_display_point(map), Bias::Left),
 781    )
 782}
 783
 784/// Finds the location of a boundary
 785pub fn find_boundary_trail(
 786    map: &DisplaySnapshot,
 787    head: DisplayPoint,
 788    is_boundary: &mut dyn FnMut(char, char) -> bool,
 789) -> (Option<DisplayPoint>, DisplayPoint) {
 790    let mut offset = head.to_offset(map, Bias::Right);
 791    let mut trail_offset = None;
 792
 793    let mut prev_ch = map.buffer_snapshot().reversed_chars_at(offset).next();
 794    let mut forward = map.buffer_snapshot().chars_at(offset).peekable();
 795
 796    // Skip newlines
 797    while let Some(&ch) = forward.peek() {
 798        if ch == '\n' {
 799            prev_ch = forward.next();
 800            offset += ch.len_utf8();
 801            trail_offset = Some(offset);
 802        } else {
 803            break;
 804        }
 805    }
 806
 807    // Find the boundary
 808    let start_offset = offset;
 809    for ch in forward {
 810        if let Some(prev_ch) = prev_ch
 811            && is_boundary(prev_ch, ch)
 812        {
 813            if start_offset == offset {
 814                trail_offset = Some(offset);
 815            } else {
 816                break;
 817            }
 818        }
 819        offset += ch.len_utf8();
 820        prev_ch = Some(ch);
 821    }
 822
 823    let trail = trail_offset
 824        .map(|trail_offset| map.clip_point(trail_offset.to_display_point(map), Bias::Right));
 825
 826    (
 827        trail,
 828        map.clip_point(offset.to_display_point(map), Bias::Right),
 829    )
 830}
 831
 832pub fn find_boundary(
 833    map: &DisplaySnapshot,
 834    from: DisplayPoint,
 835    find_range: FindRange,
 836    is_boundary: &mut dyn FnMut(char, char) -> bool,
 837) -> DisplayPoint {
 838    find_boundary_point(map, from, find_range, is_boundary, false)
 839}
 840
 841pub fn find_boundary_exclusive(
 842    map: &DisplaySnapshot,
 843    from: DisplayPoint,
 844    find_range: FindRange,
 845    is_boundary: &mut dyn FnMut(char, char) -> bool,
 846) -> DisplayPoint {
 847    find_boundary_point(map, from, find_range, is_boundary, true)
 848}
 849
 850/// Returns an iterator over the characters following a given offset in the [`DisplaySnapshot`].
 851/// The returned value also contains a range of the start/end of a returned character in
 852/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 853pub fn chars_after(
 854    map: &DisplaySnapshot,
 855    mut offset: MultiBufferOffset,
 856) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 857    map.buffer_snapshot().chars_at(offset).map(move |ch| {
 858        let before = offset;
 859        offset += ch.len_utf8();
 860        (ch, before..offset)
 861    })
 862}
 863
 864/// Returns a reverse iterator over the characters following a given offset in the [`DisplaySnapshot`].
 865/// The returned value also contains a range of the start/end of a returned character in
 866/// the [`DisplaySnapshot`]. The offsets are relative to the start of a buffer.
 867pub fn chars_before(
 868    map: &DisplaySnapshot,
 869    mut offset: MultiBufferOffset,
 870) -> impl Iterator<Item = (char, Range<MultiBufferOffset>)> + '_ {
 871    map.buffer_snapshot()
 872        .reversed_chars_at(offset)
 873        .map(move |ch| {
 874            let after = offset;
 875            offset -= ch.len_utf8();
 876            (ch, offset..after)
 877        })
 878}
 879
 880/// Returns a list of lines (represented as a [`DisplayPoint`] range) contained
 881/// within a passed range.
 882///
 883/// The line ranges are **always* going to be in bounds of a requested range, which means that
 884/// the first and the last lines might not necessarily represent the
 885/// full range of a logical line (as their `.start`/`.end` values are clipped to those of a passed in range).
 886pub fn split_display_range_by_lines(
 887    map: &DisplaySnapshot,
 888    range: Range<DisplayPoint>,
 889) -> Vec<Range<DisplayPoint>> {
 890    let mut result = Vec::new();
 891
 892    let mut start = range.start;
 893    // Loop over all the covered rows until the one containing the range end
 894    for row in range.start.row().0..range.end.row().0 {
 895        let row_end_column = map.line_len(DisplayRow(row));
 896        let end = map.clip_point(
 897            DisplayPoint::new(DisplayRow(row), row_end_column),
 898            Bias::Left,
 899        );
 900        if start != end {
 901            result.push(start..end);
 902        }
 903        start = map.clip_point(DisplayPoint::new(DisplayRow(row + 1), 0), Bias::Left);
 904    }
 905
 906    // Add the final range from the start of the last end to the original range end.
 907    result.push(start..range.end);
 908
 909    result
 910}
 911
 912#[cfg(test)]
 913mod tests {
 914    use super::*;
 915    use crate::{
 916        Buffer, DisplayMap, DisplayRow, FoldPlaceholder, MultiBuffer,
 917        inlays::Inlay,
 918        test::{editor_test_context::EditorTestContext, marked_display_snapshot},
 919    };
 920    use gpui::{AppContext as _, font, px};
 921    use language::Capability;
 922    use multi_buffer::PathKey;
 923    use project::project_settings::DiagnosticSeverity;
 924    use settings::SettingsStore;
 925    use util::post_inc;
 926
 927    #[gpui::test]
 928    fn test_previous_word_start(cx: &mut gpui::App) {
 929        init_test(cx);
 930
 931        fn assert(marked_text: &str, cx: &mut gpui::App) {
 932            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 933            let actual = previous_word_start(&snapshot, display_points[1]);
 934            let expected = display_points[0];
 935            if actual != expected {
 936                eprintln!(
 937                    "previous_word_start mismatch for '{}': actual={:?}, expected={:?}",
 938                    marked_text, actual, expected
 939                );
 940            }
 941            assert_eq!(actual, expected);
 942        }
 943
 944        assert("\nˇ   ˇlorem", cx);
 945        assert("ˇ\nˇ   lorem", cx);
 946        assert("    ˇloremˇ", cx);
 947        assert("ˇ    ˇlorem", cx);
 948        assert("    ˇlorˇem", cx);
 949        assert("\nlorem\nˇ   ˇipsum", cx);
 950        assert("\n\nˇ\nˇ", cx);
 951        assert("    ˇlorem  ˇipsum", cx);
 952        assert("ˇlorem-ˇipsum", cx);
 953        assert("loremˇ-#$@ˇipsum", cx);
 954        assert("ˇlorem_ˇipsum", cx);
 955        assert(" ˇdefγˇ", cx);
 956        assert(" ˇbcΔˇ", cx);
 957        // Test punctuation skipping behavior
 958        assert("ˇhello.ˇ", cx);
 959        assert("helloˇ...ˇ", cx);
 960        assert("helloˇ.---..ˇtest", cx);
 961        assert("test  ˇ.--ˇtest", cx);
 962        assert("oneˇ,;:!?ˇtwo", cx);
 963    }
 964
 965    #[gpui::test]
 966    fn test_previous_subword_start(cx: &mut gpui::App) {
 967        init_test(cx);
 968
 969        fn assert(marked_text: &str, cx: &mut gpui::App) {
 970            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
 971            assert_eq!(
 972                previous_subword_start(&snapshot, display_points[1]),
 973                display_points[0]
 974            );
 975        }
 976
 977        // Subword boundaries are respected
 978        assert("loremˇ_ˇipsum", cx);
 979        assert("lorem_ˇipsumˇ", cx);
 980        assert("ˇloremˇ_ipsum", cx);
 981        assert("lorem_ˇipsumˇ_dolor", cx);
 982        assert("loremˇIpˇsum", cx);
 983        assert("loremˇIpsumˇ", cx);
 984
 985        // Word boundaries are still respected
 986        assert("\nˇ   ˇlorem", cx);
 987        assert("    ˇloremˇ", cx);
 988        assert("    ˇlorˇem", cx);
 989        assert("\nlorem\nˇ   ˇipsum", cx);
 990        assert("\n\nˇ\nˇ", cx);
 991        assert("    ˇlorem  ˇipsum", cx);
 992        assert("loremˇ-ˇipsum", cx);
 993        assert("loremˇ-#$@ˇipsum", cx);
 994        assert(" ˇdefγˇ", cx);
 995        assert(" bcˇΔˇ", cx);
 996        assert(" ˇbcδˇ", cx);
 997        assert(" abˇ——ˇcd", cx);
 998    }
 999
1000    #[gpui::test]
1001    fn test_find_preceding_boundary(cx: &mut gpui::App) {
1002        init_test(cx);
1003
1004        fn assert(
1005            marked_text: &str,
1006            cx: &mut gpui::App,
1007            is_boundary: &mut dyn FnMut(char, char) -> bool,
1008        ) {
1009            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1010            assert_eq!(
1011                find_preceding_boundary_display_point(
1012                    &snapshot,
1013                    display_points[1],
1014                    FindRange::MultiLine,
1015                    is_boundary
1016                ),
1017                display_points[0]
1018            );
1019        }
1020
1021        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1022            left == 'c' && right == 'd'
1023        });
1024        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, right| {
1025            left == '\n' && right == 'g'
1026        });
1027        let mut line_count = 0;
1028        assert("abcdef\nˇgh\nijˇk", cx, &mut |left, _| {
1029            if left == '\n' {
1030                line_count += 1;
1031                line_count == 2
1032            } else {
1033                false
1034            }
1035        });
1036    }
1037
1038    #[gpui::test]
1039    fn test_find_preceding_boundary_with_inlays(cx: &mut gpui::App) {
1040        init_test(cx);
1041
1042        let input_text = "abcdefghijklmnopqrstuvwxys";
1043        let font = font("Helvetica");
1044        let font_size = px(14.0);
1045        let buffer = MultiBuffer::build_simple(input_text, cx);
1046        let buffer_snapshot = buffer.read(cx).snapshot(cx);
1047
1048        let display_map = cx.new(|cx| {
1049            DisplayMap::new(
1050                buffer,
1051                font,
1052                font_size,
1053                None,
1054                1,
1055                1,
1056                FoldPlaceholder::test(),
1057                DiagnosticSeverity::Warning,
1058                cx,
1059            )
1060        });
1061
1062        // add all kinds of inlays between two word boundaries: we should be able to cross them all, when looking for another boundary
1063        let mut id = 0;
1064        let inlays = (0..buffer_snapshot.len().0)
1065            .flat_map(|offset| {
1066                let offset = MultiBufferOffset(offset);
1067                [
1068                    Inlay::edit_prediction(
1069                        post_inc(&mut id),
1070                        buffer_snapshot.anchor_before(offset),
1071                        "test",
1072                    ),
1073                    Inlay::edit_prediction(
1074                        post_inc(&mut id),
1075                        buffer_snapshot.anchor_after(offset),
1076                        "test",
1077                    ),
1078                    Inlay::mock_hint(
1079                        post_inc(&mut id),
1080                        buffer_snapshot.anchor_before(offset),
1081                        "test",
1082                    ),
1083                    Inlay::mock_hint(
1084                        post_inc(&mut id),
1085                        buffer_snapshot.anchor_after(offset),
1086                        "test",
1087                    ),
1088                ]
1089            })
1090            .collect();
1091        let snapshot = display_map.update(cx, |map, cx| {
1092            map.splice_inlays(&[], inlays, cx);
1093            map.snapshot(cx)
1094        });
1095
1096        assert_eq!(
1097            find_preceding_boundary_display_point(
1098                &snapshot,
1099                buffer_snapshot.len().to_display_point(&snapshot),
1100                FindRange::MultiLine,
1101                &mut |left, _| left == 'e',
1102            ),
1103            snapshot
1104                .buffer_snapshot()
1105                .offset_to_point(MultiBufferOffset(5))
1106                .to_display_point(&snapshot),
1107            "Should not stop at inlays when looking for boundaries"
1108        );
1109    }
1110
1111    #[gpui::test]
1112    fn test_next_word_end(cx: &mut gpui::App) {
1113        init_test(cx);
1114
1115        fn assert(marked_text: &str, cx: &mut gpui::App) {
1116            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1117            let actual = next_word_end(&snapshot, display_points[0]);
1118            let expected = display_points[1];
1119            if actual != expected {
1120                eprintln!(
1121                    "next_word_end mismatch for '{}': actual={:?}, expected={:?}",
1122                    marked_text, actual, expected
1123                );
1124            }
1125            assert_eq!(actual, expected);
1126        }
1127
1128        assert("\nˇ   loremˇ", cx);
1129        assert("    ˇloremˇ", cx);
1130        assert("    lorˇemˇ", cx);
1131        assert("    loremˇ    ˇ\nipsum\n", cx);
1132        assert("\nˇ\nˇ\n\n", cx);
1133        assert("loremˇ    ipsumˇ   ", cx);
1134        assert("loremˇ-ipsumˇ", cx);
1135        assert("loremˇ#$@-ˇipsum", cx);
1136        assert("loremˇ_ipsumˇ", cx);
1137        assert(" ˇbcΔˇ", cx);
1138        assert(" abˇ——ˇcd", cx);
1139        // Test punctuation skipping behavior
1140        assert("ˇ.helloˇ", cx);
1141        assert("display_pointsˇ[0ˇ]", cx);
1142        assert("ˇ...ˇhello", cx);
1143        assert("helloˇ.---..ˇtest", cx);
1144        assert("testˇ.--ˇ test", cx);
1145        assert("oneˇ,;:!?ˇtwo", cx);
1146    }
1147
1148    #[gpui::test]
1149    fn test_next_subword_end(cx: &mut gpui::App) {
1150        init_test(cx);
1151
1152        fn assert(marked_text: &str, cx: &mut gpui::App) {
1153            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1154            assert_eq!(
1155                next_subword_end(&snapshot, display_points[0]),
1156                display_points[1]
1157            );
1158        }
1159
1160        // Subword boundaries are respected
1161        assert("loremˇ_ˇipsum", cx);
1162        assert("ˇloremˇ_ipsum", cx);
1163        assert("loremˇ_ˇipsum", cx);
1164        assert("lorem_ˇipsumˇ_dolor", cx);
1165        assert("loˇremˇIpsum", cx);
1166        assert("loremˇIpsumˇDolor", cx);
1167
1168        // Word boundaries are still respected
1169        assert("\nˇ   loremˇ", cx);
1170        assert("    ˇloremˇ", cx);
1171        assert("    lorˇemˇ", cx);
1172        assert("    loremˇ    ˇ\nipsum\n", cx);
1173        assert("\nˇ\nˇ\n\n", cx);
1174        assert("loremˇ    ipsumˇ   ", cx);
1175        assert("loremˇ-ˇipsum", cx);
1176        assert("loremˇ#$@-ˇipsum", cx);
1177        assert("loremˇ_ˇipsum", cx);
1178        assert(" ˇbcˇΔ", cx);
1179        assert(" abˇ——ˇcd", cx);
1180    }
1181
1182    #[gpui::test]
1183    fn test_find_boundary(cx: &mut gpui::App) {
1184        init_test(cx);
1185
1186        fn assert(
1187            marked_text: &str,
1188            cx: &mut gpui::App,
1189            is_boundary: &mut dyn FnMut(char, char) -> bool,
1190        ) {
1191            let (snapshot, display_points) = marked_display_snapshot(marked_text, cx);
1192            assert_eq!(
1193                find_boundary(
1194                    &snapshot,
1195                    display_points[0],
1196                    FindRange::MultiLine,
1197                    is_boundary,
1198                ),
1199                display_points[1]
1200            );
1201        }
1202
1203        assert("abcˇdef\ngh\nijˇk", cx, &mut |left, right| {
1204            left == 'j' && right == 'k'
1205        });
1206        assert("abˇcdef\ngh\nˇijk", cx, &mut |left, right| {
1207            left == '\n' && right == 'i'
1208        });
1209        let mut line_count = 0;
1210        assert("abcˇdef\ngh\nˇijk", cx, &mut |left, _| {
1211            if left == '\n' {
1212                line_count += 1;
1213                line_count == 2
1214            } else {
1215                false
1216            }
1217        });
1218    }
1219
1220    #[gpui::test]
1221    async fn test_move_up_and_down_with_excerpts(cx: &mut gpui::TestAppContext) {
1222        cx.update(|cx| {
1223            init_test(cx);
1224        });
1225
1226        let mut cx = EditorTestContext::new(cx).await;
1227        let editor = cx.editor.clone();
1228        let window = cx.window;
1229        _ = cx.update_window(window, |_, window, cx| {
1230            let text_layout_details =
1231                editor.update(cx, |editor, cx| editor.text_layout_details(window, cx));
1232
1233            let font = font("Helvetica");
1234
1235            let buffer = cx.new(|cx| Buffer::local("abc\ndefg\na\na\na\nhijkl\nmn", cx));
1236            let multibuffer = cx.new(|cx| {
1237                let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
1238                multibuffer.set_excerpts_for_path(
1239                    PathKey::sorted(0),
1240                    buffer.clone(),
1241                    [
1242                        Point::new(0, 0)..Point::new(1, 4),
1243                        Point::new(5, 0)..Point::new(6, 2),
1244                    ],
1245                    0,
1246                    cx,
1247                );
1248                multibuffer
1249            });
1250            let display_map = cx.new(|cx| {
1251                DisplayMap::new(
1252                    multibuffer,
1253                    font,
1254                    px(14.0),
1255                    None,
1256                    0,
1257                    1,
1258                    FoldPlaceholder::test(),
1259                    DiagnosticSeverity::Warning,
1260                    cx,
1261                )
1262            });
1263            let snapshot = display_map.update(cx, |map, cx| map.snapshot(cx));
1264
1265            assert_eq!(snapshot.text(), "abc\ndefg\n\nhijkl\nmn");
1266
1267            let col_2_x = snapshot
1268                .x_for_display_point(DisplayPoint::new(DisplayRow(0), 2), &text_layout_details);
1269
1270            // Can't move up into the first excerpt's header
1271            assert_eq!(
1272                up(
1273                    &snapshot,
1274                    DisplayPoint::new(DisplayRow(0), 2),
1275                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1276                    false,
1277                    &text_layout_details
1278                ),
1279                (
1280                    DisplayPoint::new(DisplayRow(0), 0),
1281                    SelectionGoal::HorizontalPosition(f64::from(col_2_x)),
1282                ),
1283            );
1284            assert_eq!(
1285                up(
1286                    &snapshot,
1287                    DisplayPoint::new(DisplayRow(0), 0),
1288                    SelectionGoal::None,
1289                    false,
1290                    &text_layout_details
1291                ),
1292                (
1293                    DisplayPoint::new(DisplayRow(0), 0),
1294                    SelectionGoal::HorizontalPosition(0.0),
1295                ),
1296            );
1297
1298            let col_4_x = snapshot
1299                .x_for_display_point(DisplayPoint::new(DisplayRow(1), 4), &text_layout_details);
1300
1301            // Move up and down within first excerpt
1302            assert_eq!(
1303                up(
1304                    &snapshot,
1305                    DisplayPoint::new(DisplayRow(1), 4),
1306                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1307                    false,
1308                    &text_layout_details
1309                ),
1310                (
1311                    DisplayPoint::new(DisplayRow(0), 3),
1312                    SelectionGoal::HorizontalPosition(col_4_x.into())
1313                ),
1314            );
1315            assert_eq!(
1316                down(
1317                    &snapshot,
1318                    DisplayPoint::new(DisplayRow(0), 3),
1319                    SelectionGoal::HorizontalPosition(col_4_x.into()),
1320                    false,
1321                    &text_layout_details
1322                ),
1323                (
1324                    DisplayPoint::new(DisplayRow(1), 4),
1325                    SelectionGoal::HorizontalPosition(col_4_x.into())
1326                ),
1327            );
1328
1329            let col_5_x = snapshot
1330                .x_for_display_point(DisplayPoint::new(DisplayRow(3), 5), &text_layout_details);
1331
1332            // Move up and down across second excerpt's header
1333            assert_eq!(
1334                up(
1335                    &snapshot,
1336                    DisplayPoint::new(DisplayRow(3), 5),
1337                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1338                    false,
1339                    &text_layout_details
1340                ),
1341                (
1342                    DisplayPoint::new(DisplayRow(1), 4),
1343                    SelectionGoal::HorizontalPosition(col_5_x.into())
1344                ),
1345            );
1346            assert_eq!(
1347                down(
1348                    &snapshot,
1349                    DisplayPoint::new(DisplayRow(1), 4),
1350                    SelectionGoal::HorizontalPosition(col_5_x.into()),
1351                    false,
1352                    &text_layout_details
1353                ),
1354                (
1355                    DisplayPoint::new(DisplayRow(3), 5),
1356                    SelectionGoal::HorizontalPosition(col_5_x.into())
1357                ),
1358            );
1359
1360            let max_point_x = snapshot
1361                .x_for_display_point(DisplayPoint::new(DisplayRow(4), 2), &text_layout_details);
1362
1363            // Can't move down off the end, and attempting to do so leaves the selection goal unchanged
1364            assert_eq!(
1365                down(
1366                    &snapshot,
1367                    DisplayPoint::new(DisplayRow(4), 0),
1368                    SelectionGoal::HorizontalPosition(0.0),
1369                    false,
1370                    &text_layout_details
1371                ),
1372                (
1373                    DisplayPoint::new(DisplayRow(4), 2),
1374                    SelectionGoal::HorizontalPosition(0.0)
1375                ),
1376            );
1377            assert_eq!(
1378                down(
1379                    &snapshot,
1380                    DisplayPoint::new(DisplayRow(4), 2),
1381                    SelectionGoal::HorizontalPosition(max_point_x.into()),
1382                    false,
1383                    &text_layout_details
1384                ),
1385                (
1386                    DisplayPoint::new(DisplayRow(4), 2),
1387                    SelectionGoal::HorizontalPosition(max_point_x.into())
1388                ),
1389            );
1390        });
1391    }
1392
1393    fn init_test(cx: &mut gpui::App) {
1394        let settings_store = SettingsStore::test(cx);
1395        cx.set_global(settings_store);
1396        theme::init(theme::LoadThemes::JustBase, cx);
1397        crate::init(cx);
1398    }
1399}