tab_map.rs

  1use super::{
  2    fold_map::{self, FoldChunks, FoldEdit, FoldPoint, FoldSnapshot},
  3    Highlights,
  4};
  5use language::{Chunk, Point};
  6use multi_buffer::MultiBufferSnapshot;
  7use std::{cmp, mem, num::NonZeroU32, ops::Range};
  8use sum_tree::Bias;
  9
 10const MAX_EXPANSION_COLUMN: u32 = 256;
 11
 12/// Keeps track of hard tabs in a text buffer.
 13///
 14/// See the [`display_map` module documentation](crate::display_map) for more information.
 15pub struct TabMap(TabSnapshot);
 16
 17impl TabMap {
 18    pub fn new(fold_snapshot: FoldSnapshot, tab_size: NonZeroU32) -> (Self, TabSnapshot) {
 19        let snapshot = TabSnapshot {
 20            fold_snapshot,
 21            tab_size,
 22            max_expansion_column: MAX_EXPANSION_COLUMN,
 23            version: 0,
 24        };
 25        (Self(snapshot.clone()), snapshot)
 26    }
 27
 28    #[cfg(test)]
 29    pub fn set_max_expansion_column(&mut self, column: u32) -> TabSnapshot {
 30        self.0.max_expansion_column = column;
 31        self.0.clone()
 32    }
 33
 34    pub fn sync(
 35        &mut self,
 36        fold_snapshot: FoldSnapshot,
 37        mut fold_edits: Vec<FoldEdit>,
 38        tab_size: NonZeroU32,
 39    ) -> (TabSnapshot, Vec<TabEdit>) {
 40        let old_snapshot = &mut self.0;
 41        let mut new_snapshot = TabSnapshot {
 42            fold_snapshot,
 43            tab_size,
 44            max_expansion_column: old_snapshot.max_expansion_column,
 45            version: old_snapshot.version,
 46        };
 47
 48        if old_snapshot.fold_snapshot.version != new_snapshot.fold_snapshot.version {
 49            new_snapshot.version += 1;
 50        }
 51
 52        let mut tab_edits = Vec::with_capacity(fold_edits.len());
 53
 54        if old_snapshot.tab_size == new_snapshot.tab_size {
 55            // Expand each edit to include the next tab on the same line as the edit,
 56            // and any subsequent tabs on that line that moved across the tab expansion
 57            // boundary.
 58            for fold_edit in &mut fold_edits {
 59                let old_end = fold_edit.old.end.to_point(&old_snapshot.fold_snapshot);
 60                let old_end_row_successor_offset = cmp::min(
 61                    FoldPoint::new(old_end.row() + 1, 0),
 62                    old_snapshot.fold_snapshot.max_point(),
 63                )
 64                .to_offset(&old_snapshot.fold_snapshot);
 65                let new_end = fold_edit.new.end.to_point(&new_snapshot.fold_snapshot);
 66
 67                let mut offset_from_edit = 0;
 68                let mut first_tab_offset = None;
 69                let mut last_tab_with_changed_expansion_offset = None;
 70                'outer: for chunk in old_snapshot.fold_snapshot.chunks(
 71                    fold_edit.old.end..old_end_row_successor_offset,
 72                    false,
 73                    Highlights::default(),
 74                ) {
 75                    for (ix, _) in chunk.text.match_indices('\t') {
 76                        let offset_from_edit = offset_from_edit + (ix as u32);
 77                        if first_tab_offset.is_none() {
 78                            first_tab_offset = Some(offset_from_edit);
 79                        }
 80
 81                        let old_column = old_end.column() + offset_from_edit;
 82                        let new_column = new_end.column() + offset_from_edit;
 83                        let was_expanded = old_column < old_snapshot.max_expansion_column;
 84                        let is_expanded = new_column < new_snapshot.max_expansion_column;
 85                        if was_expanded != is_expanded {
 86                            last_tab_with_changed_expansion_offset = Some(offset_from_edit);
 87                        } else if !was_expanded && !is_expanded {
 88                            break 'outer;
 89                        }
 90                    }
 91
 92                    offset_from_edit += chunk.text.len() as u32;
 93                    if old_end.column() + offset_from_edit >= old_snapshot.max_expansion_column
 94                        && new_end.column() + offset_from_edit >= new_snapshot.max_expansion_column
 95                    {
 96                        break;
 97                    }
 98                }
 99
100                if let Some(offset) = last_tab_with_changed_expansion_offset.or(first_tab_offset) {
101                    fold_edit.old.end.0 += offset as usize + 1;
102                    fold_edit.new.end.0 += offset as usize + 1;
103                }
104            }
105
106            // Combine any edits that overlap due to the expansion.
107            let mut ix = 1;
108            while ix < fold_edits.len() {
109                let (prev_edits, next_edits) = fold_edits.split_at_mut(ix);
110                let prev_edit = prev_edits.last_mut().unwrap();
111                let edit = &next_edits[0];
112                if prev_edit.old.end >= edit.old.start {
113                    prev_edit.old.end = edit.old.end;
114                    prev_edit.new.end = edit.new.end;
115                    fold_edits.remove(ix);
116                } else {
117                    ix += 1;
118                }
119            }
120
121            for fold_edit in fold_edits {
122                let old_start = fold_edit.old.start.to_point(&old_snapshot.fold_snapshot);
123                let old_end = fold_edit.old.end.to_point(&old_snapshot.fold_snapshot);
124                let new_start = fold_edit.new.start.to_point(&new_snapshot.fold_snapshot);
125                let new_end = fold_edit.new.end.to_point(&new_snapshot.fold_snapshot);
126                tab_edits.push(TabEdit {
127                    old: old_snapshot.to_tab_point(old_start)..old_snapshot.to_tab_point(old_end),
128                    new: new_snapshot.to_tab_point(new_start)..new_snapshot.to_tab_point(new_end),
129                });
130            }
131        } else {
132            new_snapshot.version += 1;
133            tab_edits.push(TabEdit {
134                old: TabPoint::zero()..old_snapshot.max_point(),
135                new: TabPoint::zero()..new_snapshot.max_point(),
136            });
137        }
138
139        *old_snapshot = new_snapshot;
140        (old_snapshot.clone(), tab_edits)
141    }
142}
143
144#[derive(Clone)]
145pub struct TabSnapshot {
146    pub fold_snapshot: FoldSnapshot,
147    pub tab_size: NonZeroU32,
148    pub max_expansion_column: u32,
149    pub version: usize,
150}
151
152impl TabSnapshot {
153    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
154        &self.fold_snapshot.inlay_snapshot.buffer
155    }
156
157    pub fn line_len(&self, row: u32) -> u32 {
158        let max_point = self.max_point();
159        if row < max_point.row() {
160            self.to_tab_point(FoldPoint::new(row, self.fold_snapshot.line_len(row)))
161                .0
162                .column
163        } else {
164            max_point.column()
165        }
166    }
167
168    pub fn text_summary(&self) -> TextSummary {
169        self.text_summary_for_range(TabPoint::zero()..self.max_point())
170    }
171
172    pub fn text_summary_for_range(&self, range: Range<TabPoint>) -> TextSummary {
173        let input_start = self.to_fold_point(range.start, Bias::Left).0;
174        let input_end = self.to_fold_point(range.end, Bias::Right).0;
175        let input_summary = self
176            .fold_snapshot
177            .text_summary_for_range(input_start..input_end);
178
179        let mut first_line_chars = 0;
180        let line_end = if range.start.row() == range.end.row() {
181            range.end
182        } else {
183            self.max_point()
184        };
185        for c in self
186            .chunks(range.start..line_end, false, Highlights::default())
187            .flat_map(|chunk| chunk.text.chars())
188        {
189            if c == '\n' {
190                break;
191            }
192            first_line_chars += 1;
193        }
194
195        let mut last_line_chars = 0;
196        if range.start.row() == range.end.row() {
197            last_line_chars = first_line_chars;
198        } else {
199            for _ in self
200                .chunks(
201                    TabPoint::new(range.end.row(), 0)..range.end,
202                    false,
203                    Highlights::default(),
204                )
205                .flat_map(|chunk| chunk.text.chars())
206            {
207                last_line_chars += 1;
208            }
209        }
210
211        TextSummary {
212            lines: range.end.0 - range.start.0,
213            first_line_chars,
214            last_line_chars,
215            longest_row: input_summary.longest_row,
216            longest_row_chars: input_summary.longest_row_chars,
217        }
218    }
219
220    pub fn chunks<'a>(
221        &'a self,
222        range: Range<TabPoint>,
223        language_aware: bool,
224        highlights: Highlights<'a>,
225    ) -> TabChunks<'a> {
226        let (input_start, expanded_char_column, to_next_stop) =
227            self.to_fold_point(range.start, Bias::Left);
228        let input_column = input_start.column();
229        let input_start = input_start.to_offset(&self.fold_snapshot);
230        let input_end = self
231            .to_fold_point(range.end, Bias::Right)
232            .0
233            .to_offset(&self.fold_snapshot);
234        let to_next_stop = if range.start.0 + Point::new(0, to_next_stop) > range.end.0 {
235            range.end.column() - range.start.column()
236        } else {
237            to_next_stop
238        };
239
240        TabChunks {
241            fold_chunks: self.fold_snapshot.chunks(
242                input_start..input_end,
243                language_aware,
244                highlights,
245            ),
246            input_column,
247            column: expanded_char_column,
248            max_expansion_column: self.max_expansion_column,
249            output_position: range.start.0,
250            max_output_position: range.end.0,
251            tab_size: self.tab_size,
252            chunk: Chunk {
253                text: &SPACES[0..(to_next_stop as usize)],
254                is_tab: true,
255                ..Default::default()
256            },
257            inside_leading_tab: to_next_stop > 0,
258        }
259    }
260
261    pub fn buffer_rows(&self, row: u32) -> fold_map::FoldBufferRows<'_> {
262        self.fold_snapshot.buffer_rows(row)
263    }
264
265    #[cfg(test)]
266    pub fn text(&self) -> String {
267        self.chunks(
268            TabPoint::zero()..self.max_point(),
269            false,
270            Highlights::default(),
271        )
272        .map(|chunk| chunk.text)
273        .collect()
274    }
275
276    pub fn max_point(&self) -> TabPoint {
277        self.to_tab_point(self.fold_snapshot.max_point())
278    }
279
280    pub fn clip_point(&self, point: TabPoint, bias: Bias) -> TabPoint {
281        self.to_tab_point(
282            self.fold_snapshot
283                .clip_point(self.to_fold_point(point, bias).0, bias),
284        )
285    }
286
287    pub fn to_tab_point(&self, input: FoldPoint) -> TabPoint {
288        let chars = self.fold_snapshot.chars_at(FoldPoint::new(input.row(), 0));
289        let expanded = self.expand_tabs(chars, input.column());
290        TabPoint::new(input.row(), expanded)
291    }
292
293    pub fn to_fold_point(&self, output: TabPoint, bias: Bias) -> (FoldPoint, u32, u32) {
294        let chars = self.fold_snapshot.chars_at(FoldPoint::new(output.row(), 0));
295        let expanded = output.column();
296        let (collapsed, expanded_char_column, to_next_stop) =
297            self.collapse_tabs(chars, expanded, bias);
298        (
299            FoldPoint::new(output.row(), collapsed),
300            expanded_char_column,
301            to_next_stop,
302        )
303    }
304
305    pub fn make_tab_point(&self, point: Point, bias: Bias) -> TabPoint {
306        let inlay_point = self.fold_snapshot.inlay_snapshot.to_inlay_point(point);
307        let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
308        self.to_tab_point(fold_point)
309    }
310
311    pub fn to_point(&self, point: TabPoint, bias: Bias) -> Point {
312        let fold_point = self.to_fold_point(point, bias).0;
313        let inlay_point = fold_point.to_inlay_point(&self.fold_snapshot);
314        self.fold_snapshot
315            .inlay_snapshot
316            .to_buffer_point(inlay_point)
317    }
318
319    fn expand_tabs(&self, chars: impl Iterator<Item = char>, column: u32) -> u32 {
320        let tab_size = self.tab_size.get();
321
322        let mut expanded_chars = 0;
323        let mut expanded_bytes = 0;
324        let mut collapsed_bytes = 0;
325        let end_column = column.min(self.max_expansion_column);
326        for c in chars {
327            if collapsed_bytes >= end_column {
328                break;
329            }
330            if c == '\t' {
331                let tab_len = tab_size - expanded_chars % tab_size;
332                expanded_bytes += tab_len;
333                expanded_chars += tab_len;
334            } else {
335                expanded_bytes += c.len_utf8() as u32;
336                expanded_chars += 1;
337            }
338            collapsed_bytes += c.len_utf8() as u32;
339        }
340        expanded_bytes + column.saturating_sub(collapsed_bytes)
341    }
342
343    fn collapse_tabs(
344        &self,
345        chars: impl Iterator<Item = char>,
346        column: u32,
347        bias: Bias,
348    ) -> (u32, u32, u32) {
349        let tab_size = self.tab_size.get();
350
351        let mut expanded_bytes = 0;
352        let mut expanded_chars = 0;
353        let mut collapsed_bytes = 0;
354        for c in chars {
355            if expanded_bytes >= column {
356                break;
357            }
358            if collapsed_bytes >= self.max_expansion_column {
359                break;
360            }
361
362            if c == '\t' {
363                let tab_len = tab_size - (expanded_chars % tab_size);
364                expanded_chars += tab_len;
365                expanded_bytes += tab_len;
366                if expanded_bytes > column {
367                    expanded_chars -= expanded_bytes - column;
368                    return match bias {
369                        Bias::Left => (collapsed_bytes, expanded_chars, expanded_bytes - column),
370                        Bias::Right => (collapsed_bytes + 1, expanded_chars, 0),
371                    };
372                }
373            } else {
374                expanded_chars += 1;
375                expanded_bytes += c.len_utf8() as u32;
376            }
377
378            if expanded_bytes > column && matches!(bias, Bias::Left) {
379                expanded_chars -= 1;
380                break;
381            }
382
383            collapsed_bytes += c.len_utf8() as u32;
384        }
385        (
386            collapsed_bytes + column.saturating_sub(expanded_bytes),
387            expanded_chars,
388            0,
389        )
390    }
391}
392
393#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
394pub struct TabPoint(pub Point);
395
396impl TabPoint {
397    pub fn new(row: u32, column: u32) -> Self {
398        Self(Point::new(row, column))
399    }
400
401    pub fn zero() -> Self {
402        Self::new(0, 0)
403    }
404
405    pub fn row(self) -> u32 {
406        self.0.row
407    }
408
409    pub fn column(self) -> u32 {
410        self.0.column
411    }
412}
413
414impl From<Point> for TabPoint {
415    fn from(point: Point) -> Self {
416        Self(point)
417    }
418}
419
420pub type TabEdit = text::Edit<TabPoint>;
421
422#[derive(Clone, Debug, Default, Eq, PartialEq)]
423pub struct TextSummary {
424    pub lines: Point,
425    pub first_line_chars: u32,
426    pub last_line_chars: u32,
427    pub longest_row: u32,
428    pub longest_row_chars: u32,
429}
430
431impl<'a> From<&'a str> for TextSummary {
432    fn from(text: &'a str) -> Self {
433        let sum = text::TextSummary::from(text);
434
435        TextSummary {
436            lines: sum.lines,
437            first_line_chars: sum.first_line_chars,
438            last_line_chars: sum.last_line_chars,
439            longest_row: sum.longest_row,
440            longest_row_chars: sum.longest_row_chars,
441        }
442    }
443}
444
445impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
446    fn add_assign(&mut self, other: &'a Self) {
447        let joined_chars = self.last_line_chars + other.first_line_chars;
448        if joined_chars > self.longest_row_chars {
449            self.longest_row = self.lines.row;
450            self.longest_row_chars = joined_chars;
451        }
452        if other.longest_row_chars > self.longest_row_chars {
453            self.longest_row = self.lines.row + other.longest_row;
454            self.longest_row_chars = other.longest_row_chars;
455        }
456
457        if self.lines.row == 0 {
458            self.first_line_chars += other.first_line_chars;
459        }
460
461        if other.lines.row == 0 {
462            self.last_line_chars += other.first_line_chars;
463        } else {
464            self.last_line_chars = other.last_line_chars;
465        }
466
467        self.lines += &other.lines;
468    }
469}
470
471// Handles a tab width <= 16
472const SPACES: &str = "                ";
473
474pub struct TabChunks<'a> {
475    fold_chunks: FoldChunks<'a>,
476    chunk: Chunk<'a>,
477    column: u32,
478    max_expansion_column: u32,
479    output_position: Point,
480    input_column: u32,
481    max_output_position: Point,
482    tab_size: NonZeroU32,
483    inside_leading_tab: bool,
484}
485
486impl<'a> Iterator for TabChunks<'a> {
487    type Item = Chunk<'a>;
488
489    fn next(&mut self) -> Option<Self::Item> {
490        if self.chunk.text.is_empty() {
491            if let Some(chunk) = self.fold_chunks.next() {
492                self.chunk = chunk;
493                if self.inside_leading_tab {
494                    self.chunk.text = &self.chunk.text[1..];
495                    self.inside_leading_tab = false;
496                    self.input_column += 1;
497                }
498            } else {
499                return None;
500            }
501        }
502
503        for (ix, c) in self.chunk.text.char_indices() {
504            match c {
505                '\t' => {
506                    if ix > 0 {
507                        let (prefix, suffix) = self.chunk.text.split_at(ix);
508                        self.chunk.text = suffix;
509                        return Some(Chunk {
510                            text: prefix,
511                            ..self.chunk.clone()
512                        });
513                    } else {
514                        self.chunk.text = &self.chunk.text[1..];
515                        let tab_size = if self.input_column < self.max_expansion_column {
516                            self.tab_size.get()
517                        } else {
518                            1
519                        };
520                        let mut len = tab_size - self.column % tab_size;
521                        let next_output_position = cmp::min(
522                            self.output_position + Point::new(0, len),
523                            self.max_output_position,
524                        );
525                        len = next_output_position.column - self.output_position.column;
526                        self.column += len;
527                        self.input_column += 1;
528                        self.output_position = next_output_position;
529                        return Some(Chunk {
530                            text: &SPACES[..len as usize],
531                            is_tab: true,
532                            ..self.chunk.clone()
533                        });
534                    }
535                }
536                '\n' => {
537                    self.column = 0;
538                    self.input_column = 0;
539                    self.output_position += Point::new(1, 0);
540                }
541                _ => {
542                    self.column += 1;
543                    if !self.inside_leading_tab {
544                        self.input_column += c.len_utf8() as u32;
545                    }
546                    self.output_position.column += c.len_utf8() as u32;
547                }
548            }
549        }
550
551        Some(mem::take(&mut self.chunk))
552    }
553}
554
555#[cfg(test)]
556mod tests {
557    use super::*;
558    use crate::{
559        display_map::{fold_map::FoldMap, inlay_map::InlayMap},
560        MultiBuffer,
561    };
562    use rand::{prelude::StdRng, Rng};
563
564    #[gpui::test]
565    fn test_expand_tabs(cx: &mut gpui::AppContext) {
566        let buffer = MultiBuffer::build_simple("", cx);
567        let buffer_snapshot = buffer.read(cx).snapshot(cx);
568        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
569        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
570        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
571
572        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 0), 0);
573        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 1), 4);
574        assert_eq!(tab_snapshot.expand_tabs("\ta".chars(), 2), 5);
575    }
576
577    #[gpui::test]
578    fn test_long_lines(cx: &mut gpui::AppContext) {
579        let max_expansion_column = 12;
580        let input = "A\tBC\tDEF\tG\tHI\tJ\tK\tL\tM";
581        let output = "A   BC  DEF G   HI J K L M";
582
583        let buffer = MultiBuffer::build_simple(input, cx);
584        let buffer_snapshot = buffer.read(cx).snapshot(cx);
585        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
586        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
587        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
588
589        tab_snapshot.max_expansion_column = max_expansion_column;
590        assert_eq!(tab_snapshot.text(), output);
591
592        for (ix, c) in input.char_indices() {
593            assert_eq!(
594                tab_snapshot
595                    .chunks(
596                        TabPoint::new(0, ix as u32)..tab_snapshot.max_point(),
597                        false,
598                        Highlights::default(),
599                    )
600                    .map(|c| c.text)
601                    .collect::<String>(),
602                &output[ix..],
603                "text from index {ix}"
604            );
605
606            if c != '\t' {
607                let input_point = Point::new(0, ix as u32);
608                let output_point = Point::new(0, output.find(c).unwrap() as u32);
609                assert_eq!(
610                    tab_snapshot.to_tab_point(FoldPoint(input_point)),
611                    TabPoint(output_point),
612                    "to_tab_point({input_point:?})"
613                );
614                assert_eq!(
615                    tab_snapshot
616                        .to_fold_point(TabPoint(output_point), Bias::Left)
617                        .0,
618                    FoldPoint(input_point),
619                    "to_fold_point({output_point:?})"
620                );
621            }
622        }
623    }
624
625    #[gpui::test]
626    fn test_long_lines_with_character_spanning_max_expansion_column(cx: &mut gpui::AppContext) {
627        let max_expansion_column = 8;
628        let input = "abcdefg⋯hij";
629
630        let buffer = MultiBuffer::build_simple(input, cx);
631        let buffer_snapshot = buffer.read(cx).snapshot(cx);
632        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
633        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
634        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
635
636        tab_snapshot.max_expansion_column = max_expansion_column;
637        assert_eq!(tab_snapshot.text(), input);
638    }
639
640    #[gpui::test]
641    fn test_marking_tabs(cx: &mut gpui::AppContext) {
642        let input = "\t \thello";
643
644        let buffer = MultiBuffer::build_simple(&input, cx);
645        let buffer_snapshot = buffer.read(cx).snapshot(cx);
646        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
647        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
648        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
649
650        assert_eq!(
651            chunks(&tab_snapshot, TabPoint::zero()),
652            vec![
653                ("    ".to_string(), true),
654                (" ".to_string(), false),
655                ("   ".to_string(), true),
656                ("hello".to_string(), false),
657            ]
658        );
659        assert_eq!(
660            chunks(&tab_snapshot, TabPoint::new(0, 2)),
661            vec![
662                ("  ".to_string(), true),
663                (" ".to_string(), false),
664                ("   ".to_string(), true),
665                ("hello".to_string(), false),
666            ]
667        );
668
669        fn chunks(snapshot: &TabSnapshot, start: TabPoint) -> Vec<(String, bool)> {
670            let mut chunks = Vec::new();
671            let mut was_tab = false;
672            let mut text = String::new();
673            for chunk in snapshot.chunks(start..snapshot.max_point(), false, Highlights::default())
674            {
675                if chunk.is_tab != was_tab {
676                    if !text.is_empty() {
677                        chunks.push((mem::take(&mut text), was_tab));
678                    }
679                    was_tab = chunk.is_tab;
680                }
681                text.push_str(chunk.text);
682            }
683
684            if !text.is_empty() {
685                chunks.push((text, was_tab));
686            }
687            chunks
688        }
689    }
690
691    #[gpui::test(iterations = 100)]
692    fn test_random_tabs(cx: &mut gpui::AppContext, mut rng: StdRng) {
693        let tab_size = NonZeroU32::new(rng.gen_range(1..=4)).unwrap();
694        let len = rng.gen_range(0..30);
695        let buffer = if rng.gen() {
696            let text = util::RandomCharIter::new(&mut rng)
697                .take(len)
698                .collect::<String>();
699            MultiBuffer::build_simple(&text, cx)
700        } else {
701            MultiBuffer::build_random(&mut rng, cx)
702        };
703        let buffer_snapshot = buffer.read(cx).snapshot(cx);
704        log::info!("Buffer text: {:?}", buffer_snapshot.text());
705
706        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
707        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
708        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
709        fold_map.randomly_mutate(&mut rng);
710        let (fold_snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
711        log::info!("FoldMap text: {:?}", fold_snapshot.text());
712        let (inlay_snapshot, _) = inlay_map.randomly_mutate(&mut 0, &mut rng);
713        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
714
715        let (mut tab_map, _) = TabMap::new(fold_snapshot.clone(), tab_size);
716        let tabs_snapshot = tab_map.set_max_expansion_column(32);
717
718        let text = text::Rope::from(tabs_snapshot.text().as_str());
719        log::info!(
720            "TabMap text (tab size: {}): {:?}",
721            tab_size,
722            tabs_snapshot.text(),
723        );
724
725        for _ in 0..5 {
726            let end_row = rng.gen_range(0..=text.max_point().row);
727            let end_column = rng.gen_range(0..=text.line_len(end_row));
728            let mut end = TabPoint(text.clip_point(Point::new(end_row, end_column), Bias::Right));
729            let start_row = rng.gen_range(0..=text.max_point().row);
730            let start_column = rng.gen_range(0..=text.line_len(start_row));
731            let mut start =
732                TabPoint(text.clip_point(Point::new(start_row, start_column), Bias::Left));
733            if start > end {
734                mem::swap(&mut start, &mut end);
735            }
736
737            let expected_text = text
738                .chunks_in_range(text.point_to_offset(start.0)..text.point_to_offset(end.0))
739                .collect::<String>();
740            let expected_summary = TextSummary::from(expected_text.as_str());
741            assert_eq!(
742                tabs_snapshot
743                    .chunks(start..end, false, Highlights::default())
744                    .map(|c| c.text)
745                    .collect::<String>(),
746                expected_text,
747                "chunks({:?}..{:?})",
748                start,
749                end
750            );
751
752            let mut actual_summary = tabs_snapshot.text_summary_for_range(start..end);
753            if tab_size.get() > 1 && inlay_snapshot.text().contains('\t') {
754                actual_summary.longest_row = expected_summary.longest_row;
755                actual_summary.longest_row_chars = expected_summary.longest_row_chars;
756            }
757            assert_eq!(actual_summary, expected_summary);
758        }
759
760        for row in 0..=text.max_point().row {
761            assert_eq!(
762                tabs_snapshot.line_len(row),
763                text.line_len(row),
764                "line_len({row})"
765            );
766        }
767    }
768}