tab_map.rs

  1use super::{
  2    fold_map::{self, FoldChunks, FoldEdit, FoldPoint, FoldSnapshot},
  3    TextHighlights,
  4};
  5use crate::MultiBufferSnapshot;
  6use gpui::fonts::HighlightStyle;
  7use language::{Chunk, Point};
  8use std::{cmp, mem, num::NonZeroU32, ops::Range};
  9use sum_tree::Bias;
 10
 11const MAX_EXPANSION_COLUMN: u32 = 256;
 12
 13pub struct TabMap(TabSnapshot);
 14
 15impl TabMap {
 16    pub fn new(fold_snapshot: FoldSnapshot, tab_size: NonZeroU32) -> (Self, TabSnapshot) {
 17        let snapshot = TabSnapshot {
 18            fold_snapshot,
 19            tab_size,
 20            max_expansion_column: MAX_EXPANSION_COLUMN,
 21            version: 0,
 22        };
 23        (Self(snapshot.clone()), snapshot)
 24    }
 25
 26    #[cfg(test)]
 27    pub fn set_max_expansion_column(&mut self, column: u32) -> TabSnapshot {
 28        self.0.max_expansion_column = column;
 29        self.0.clone()
 30    }
 31
 32    pub fn sync(
 33        &mut self,
 34        fold_snapshot: FoldSnapshot,
 35        mut fold_edits: Vec<FoldEdit>,
 36        tab_size: NonZeroU32,
 37    ) -> (TabSnapshot, Vec<TabEdit>) {
 38        let old_snapshot = &mut self.0;
 39        let mut new_snapshot = TabSnapshot {
 40            fold_snapshot,
 41            tab_size,
 42            max_expansion_column: old_snapshot.max_expansion_column,
 43            version: old_snapshot.version,
 44        };
 45
 46        if old_snapshot.fold_snapshot.version != new_snapshot.fold_snapshot.version {
 47            new_snapshot.version += 1;
 48        }
 49
 50        let mut tab_edits = Vec::with_capacity(fold_edits.len());
 51
 52        if old_snapshot.tab_size == new_snapshot.tab_size {
 53            // Expand each edit to include the next tab on the same line as the edit,
 54            // and any subsequent tabs on that line that moved across the tab expansion
 55            // boundary.
 56            for fold_edit in &mut fold_edits {
 57                let old_end = fold_edit.old.end.to_point(&old_snapshot.fold_snapshot);
 58                let old_end_row_successor_offset = cmp::min(
 59                    FoldPoint::new(old_end.row() + 1, 0),
 60                    old_snapshot.fold_snapshot.max_point(),
 61                )
 62                .to_offset(&old_snapshot.fold_snapshot);
 63                let new_end = fold_edit.new.end.to_point(&new_snapshot.fold_snapshot);
 64
 65                let mut offset_from_edit = 0;
 66                let mut first_tab_offset = None;
 67                let mut last_tab_with_changed_expansion_offset = None;
 68                'outer: for chunk in old_snapshot.fold_snapshot.chunks(
 69                    fold_edit.old.end..old_end_row_successor_offset,
 70                    false,
 71                    None,
 72                    None,
 73                    None,
 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, None, None, None)
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                    None,
204                    None,
205                    None,
206                )
207                .flat_map(|chunk| chunk.text.chars())
208            {
209                last_line_chars += 1;
210            }
211        }
212
213        TextSummary {
214            lines: range.end.0 - range.start.0,
215            first_line_chars,
216            last_line_chars,
217            longest_row: input_summary.longest_row,
218            longest_row_chars: input_summary.longest_row_chars,
219        }
220    }
221
222    pub fn chunks<'a>(
223        &'a self,
224        range: Range<TabPoint>,
225        language_aware: bool,
226        // TODO kb extract into one struct?
227        text_highlights: Option<&'a TextHighlights>,
228        inlay_highlight_style: Option<HighlightStyle>,
229        suggestion_highlight_style: Option<HighlightStyle>,
230    ) -> TabChunks<'a> {
231        let (input_start, expanded_char_column, to_next_stop) =
232            self.to_fold_point(range.start, Bias::Left);
233        let input_column = input_start.column();
234        let input_start = input_start.to_offset(&self.fold_snapshot);
235        let input_end = self
236            .to_fold_point(range.end, Bias::Right)
237            .0
238            .to_offset(&self.fold_snapshot);
239        let to_next_stop = if range.start.0 + Point::new(0, to_next_stop) > range.end.0 {
240            range.end.column() - range.start.column()
241        } else {
242            to_next_stop
243        };
244
245        TabChunks {
246            fold_chunks: self.fold_snapshot.chunks(
247                input_start..input_end,
248                language_aware,
249                text_highlights,
250                inlay_highlight_style,
251                suggestion_highlight_style,
252            ),
253            input_column,
254            column: expanded_char_column,
255            max_expansion_column: self.max_expansion_column,
256            output_position: range.start.0,
257            max_output_position: range.end.0,
258            tab_size: self.tab_size,
259            chunk: Chunk {
260                text: &SPACES[0..(to_next_stop as usize)],
261                is_tab: true,
262                ..Default::default()
263            },
264            inside_leading_tab: to_next_stop > 0,
265        }
266    }
267
268    pub fn buffer_rows(&self, row: u32) -> fold_map::FoldBufferRows<'_> {
269        self.fold_snapshot.buffer_rows(row)
270    }
271
272    #[cfg(test)]
273    pub fn text(&self) -> String {
274        self.chunks(TabPoint::zero()..self.max_point(), false, None, None, None)
275            .map(|chunk| chunk.text)
276            .collect()
277    }
278
279    pub fn max_point(&self) -> TabPoint {
280        self.to_tab_point(self.fold_snapshot.max_point())
281    }
282
283    pub fn clip_point(&self, point: TabPoint, bias: Bias) -> TabPoint {
284        self.to_tab_point(
285            self.fold_snapshot
286                .clip_point(self.to_fold_point(point, bias).0, bias),
287        )
288    }
289
290    pub fn to_tab_point(&self, input: FoldPoint) -> TabPoint {
291        let chars = self.fold_snapshot.chars_at(FoldPoint::new(input.row(), 0));
292        let expanded = self.expand_tabs(chars, input.column());
293        TabPoint::new(input.row(), expanded)
294    }
295
296    pub fn to_fold_point(&self, output: TabPoint, bias: Bias) -> (FoldPoint, u32, u32) {
297        let chars = self.fold_snapshot.chars_at(FoldPoint::new(output.row(), 0));
298        let expanded = output.column();
299        let (collapsed, expanded_char_column, to_next_stop) =
300            self.collapse_tabs(chars, expanded, bias);
301        (
302            FoldPoint::new(output.row(), collapsed as u32),
303            expanded_char_column,
304            to_next_stop,
305        )
306    }
307
308    pub fn make_tab_point(&self, point: Point, bias: Bias) -> TabPoint {
309        let inlay_point = self.fold_snapshot.inlay_snapshot.to_inlay_point(point);
310        let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
311        self.to_tab_point(fold_point)
312    }
313
314    pub fn to_point(&self, point: TabPoint, bias: Bias) -> Point {
315        let fold_point = self.to_fold_point(point, bias).0;
316        let inlay_point = fold_point.to_inlay_point(&self.fold_snapshot);
317        self.fold_snapshot
318            .inlay_snapshot
319            .to_buffer_point(inlay_point)
320    }
321
322    fn expand_tabs(&self, chars: impl Iterator<Item = char>, column: u32) -> u32 {
323        let tab_size = self.tab_size.get();
324
325        let mut expanded_chars = 0;
326        let mut expanded_bytes = 0;
327        let mut collapsed_bytes = 0;
328        let end_column = column.min(self.max_expansion_column);
329        for c in chars {
330            if collapsed_bytes >= end_column {
331                break;
332            }
333            if c == '\t' {
334                let tab_len = tab_size - expanded_chars % tab_size;
335                expanded_bytes += tab_len;
336                expanded_chars += tab_len;
337            } else {
338                expanded_bytes += c.len_utf8() as u32;
339                expanded_chars += 1;
340            }
341            collapsed_bytes += c.len_utf8() as u32;
342        }
343        expanded_bytes + column.saturating_sub(collapsed_bytes)
344    }
345
346    fn collapse_tabs(
347        &self,
348        chars: impl Iterator<Item = char>,
349        column: u32,
350        bias: Bias,
351    ) -> (u32, u32, u32) {
352        let tab_size = self.tab_size.get();
353
354        let mut expanded_bytes = 0;
355        let mut expanded_chars = 0;
356        let mut collapsed_bytes = 0;
357        for c in chars {
358            if expanded_bytes >= column {
359                break;
360            }
361            if collapsed_bytes >= self.max_expansion_column {
362                break;
363            }
364
365            if c == '\t' {
366                let tab_len = tab_size - (expanded_chars % tab_size);
367                expanded_chars += tab_len;
368                expanded_bytes += tab_len;
369                if expanded_bytes > column {
370                    expanded_chars -= expanded_bytes - column;
371                    return match bias {
372                        Bias::Left => (collapsed_bytes, expanded_chars, expanded_bytes - column),
373                        Bias::Right => (collapsed_bytes + 1, expanded_chars, 0),
374                    };
375                }
376            } else {
377                expanded_chars += 1;
378                expanded_bytes += c.len_utf8() as u32;
379            }
380
381            if expanded_bytes > column && matches!(bias, Bias::Left) {
382                expanded_chars -= 1;
383                break;
384            }
385
386            collapsed_bytes += c.len_utf8() as u32;
387        }
388        (
389            collapsed_bytes + column.saturating_sub(expanded_bytes),
390            expanded_chars,
391            0,
392        )
393    }
394}
395
396#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
397pub struct TabPoint(pub Point);
398
399impl TabPoint {
400    pub fn new(row: u32, column: u32) -> Self {
401        Self(Point::new(row, column))
402    }
403
404    pub fn zero() -> Self {
405        Self::new(0, 0)
406    }
407
408    pub fn row(self) -> u32 {
409        self.0.row
410    }
411
412    pub fn column(self) -> u32 {
413        self.0.column
414    }
415}
416
417impl From<Point> for TabPoint {
418    fn from(point: Point) -> Self {
419        Self(point)
420    }
421}
422
423pub type TabEdit = text::Edit<TabPoint>;
424
425#[derive(Clone, Debug, Default, Eq, PartialEq)]
426pub struct TextSummary {
427    pub lines: Point,
428    pub first_line_chars: u32,
429    pub last_line_chars: u32,
430    pub longest_row: u32,
431    pub longest_row_chars: u32,
432}
433
434impl<'a> From<&'a str> for TextSummary {
435    fn from(text: &'a str) -> Self {
436        let sum = text::TextSummary::from(text);
437
438        TextSummary {
439            lines: sum.lines,
440            first_line_chars: sum.first_line_chars,
441            last_line_chars: sum.last_line_chars,
442            longest_row: sum.longest_row,
443            longest_row_chars: sum.longest_row_chars,
444        }
445    }
446}
447
448impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
449    fn add_assign(&mut self, other: &'a Self) {
450        let joined_chars = self.last_line_chars + other.first_line_chars;
451        if joined_chars > self.longest_row_chars {
452            self.longest_row = self.lines.row;
453            self.longest_row_chars = joined_chars;
454        }
455        if other.longest_row_chars > self.longest_row_chars {
456            self.longest_row = self.lines.row + other.longest_row;
457            self.longest_row_chars = other.longest_row_chars;
458        }
459
460        if self.lines.row == 0 {
461            self.first_line_chars += other.first_line_chars;
462        }
463
464        if other.lines.row == 0 {
465            self.last_line_chars += other.first_line_chars;
466        } else {
467            self.last_line_chars = other.last_line_chars;
468        }
469
470        self.lines += &other.lines;
471    }
472}
473
474// Handles a tab width <= 16
475const SPACES: &str = "                ";
476
477pub struct TabChunks<'a> {
478    fold_chunks: FoldChunks<'a>,
479    chunk: Chunk<'a>,
480    column: u32,
481    max_expansion_column: u32,
482    output_position: Point,
483    input_column: u32,
484    max_output_position: Point,
485    tab_size: NonZeroU32,
486    inside_leading_tab: bool,
487}
488
489impl<'a> Iterator for TabChunks<'a> {
490    type Item = Chunk<'a>;
491
492    fn next(&mut self) -> Option<Self::Item> {
493        if self.chunk.text.is_empty() {
494            if let Some(chunk) = self.fold_chunks.next() {
495                self.chunk = chunk;
496                if self.inside_leading_tab {
497                    self.chunk.text = &self.chunk.text[1..];
498                    self.inside_leading_tab = false;
499                    self.input_column += 1;
500                }
501            } else {
502                return None;
503            }
504        }
505
506        for (ix, c) in self.chunk.text.char_indices() {
507            match c {
508                '\t' => {
509                    if ix > 0 {
510                        let (prefix, suffix) = self.chunk.text.split_at(ix);
511                        self.chunk.text = suffix;
512                        return Some(Chunk {
513                            text: prefix,
514                            ..self.chunk
515                        });
516                    } else {
517                        self.chunk.text = &self.chunk.text[1..];
518                        let tab_size = if self.input_column < self.max_expansion_column {
519                            self.tab_size.get() as u32
520                        } else {
521                            1
522                        };
523                        let mut len = tab_size - self.column % tab_size;
524                        let next_output_position = cmp::min(
525                            self.output_position + Point::new(0, len),
526                            self.max_output_position,
527                        );
528                        len = next_output_position.column - self.output_position.column;
529                        self.column += len;
530                        self.input_column += 1;
531                        self.output_position = next_output_position;
532                        return Some(Chunk {
533                            text: &SPACES[..len as usize],
534                            is_tab: true,
535                            ..self.chunk
536                        });
537                    }
538                }
539                '\n' => {
540                    self.column = 0;
541                    self.input_column = 0;
542                    self.output_position += Point::new(1, 0);
543                }
544                _ => {
545                    self.column += 1;
546                    if !self.inside_leading_tab {
547                        self.input_column += c.len_utf8() as u32;
548                    }
549                    self.output_position.column += c.len_utf8() as u32;
550                }
551            }
552        }
553
554        Some(mem::take(&mut self.chunk))
555    }
556}
557
558#[cfg(test)]
559mod tests {
560    use super::*;
561    use crate::{
562        display_map::{fold_map::FoldMap, inlay_map::InlayMap},
563        MultiBuffer,
564    };
565    use rand::{prelude::StdRng, Rng};
566
567    #[gpui::test]
568    fn test_expand_tabs(cx: &mut gpui::AppContext) {
569        let buffer = MultiBuffer::build_simple("", cx);
570        let buffer_snapshot = buffer.read(cx).snapshot(cx);
571        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
572        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
573        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
574
575        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 0), 0);
576        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 1), 4);
577        assert_eq!(tab_snapshot.expand_tabs("\ta".chars(), 2), 5);
578    }
579
580    #[gpui::test]
581    fn test_long_lines(cx: &mut gpui::AppContext) {
582        let max_expansion_column = 12;
583        let input = "A\tBC\tDEF\tG\tHI\tJ\tK\tL\tM";
584        let output = "A   BC  DEF G   HI J K L M";
585
586        let buffer = MultiBuffer::build_simple(input, cx);
587        let buffer_snapshot = buffer.read(cx).snapshot(cx);
588        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
589        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
590        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
591
592        tab_snapshot.max_expansion_column = max_expansion_column;
593        assert_eq!(tab_snapshot.text(), output);
594
595        for (ix, c) in input.char_indices() {
596            assert_eq!(
597                tab_snapshot
598                    .chunks(
599                        TabPoint::new(0, ix as u32)..tab_snapshot.max_point(),
600                        false,
601                        None,
602                        None,
603                        None,
604                    )
605                    .map(|c| c.text)
606                    .collect::<String>(),
607                &output[ix..],
608                "text from index {ix}"
609            );
610
611            if c != '\t' {
612                let input_point = Point::new(0, ix as u32);
613                let output_point = Point::new(0, output.find(c).unwrap() as u32);
614                assert_eq!(
615                    tab_snapshot.to_tab_point(FoldPoint(input_point)),
616                    TabPoint(output_point),
617                    "to_tab_point({input_point:?})"
618                );
619                assert_eq!(
620                    tab_snapshot
621                        .to_fold_point(TabPoint(output_point), Bias::Left)
622                        .0,
623                    FoldPoint(input_point),
624                    "to_fold_point({output_point:?})"
625                );
626            }
627        }
628    }
629
630    #[gpui::test]
631    fn test_long_lines_with_character_spanning_max_expansion_column(cx: &mut gpui::AppContext) {
632        let max_expansion_column = 8;
633        let input = "abcdefg⋯hij";
634
635        let buffer = MultiBuffer::build_simple(input, cx);
636        let buffer_snapshot = buffer.read(cx).snapshot(cx);
637        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
638        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
639        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
640
641        tab_snapshot.max_expansion_column = max_expansion_column;
642        assert_eq!(tab_snapshot.text(), input);
643    }
644
645    #[gpui::test]
646    fn test_marking_tabs(cx: &mut gpui::AppContext) {
647        let input = "\t \thello";
648
649        let buffer = MultiBuffer::build_simple(&input, cx);
650        let buffer_snapshot = buffer.read(cx).snapshot(cx);
651        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
652        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
653        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
654
655        assert_eq!(
656            chunks(&tab_snapshot, TabPoint::zero()),
657            vec![
658                ("    ".to_string(), true),
659                (" ".to_string(), false),
660                ("   ".to_string(), true),
661                ("hello".to_string(), false),
662            ]
663        );
664        assert_eq!(
665            chunks(&tab_snapshot, TabPoint::new(0, 2)),
666            vec![
667                ("  ".to_string(), true),
668                (" ".to_string(), false),
669                ("   ".to_string(), true),
670                ("hello".to_string(), false),
671            ]
672        );
673
674        fn chunks(snapshot: &TabSnapshot, start: TabPoint) -> Vec<(String, bool)> {
675            let mut chunks = Vec::new();
676            let mut was_tab = false;
677            let mut text = String::new();
678            for chunk in snapshot.chunks(start..snapshot.max_point(), false, None, None, None) {
679                if chunk.is_tab != was_tab {
680                    if !text.is_empty() {
681                        chunks.push((mem::take(&mut text), was_tab));
682                    }
683                    was_tab = chunk.is_tab;
684                }
685                text.push_str(chunk.text);
686            }
687
688            if !text.is_empty() {
689                chunks.push((text, was_tab));
690            }
691            chunks
692        }
693    }
694
695    #[gpui::test(iterations = 100)]
696    fn test_random_tabs(cx: &mut gpui::AppContext, mut rng: StdRng) {
697        let tab_size = NonZeroU32::new(rng.gen_range(1..=4)).unwrap();
698        let len = rng.gen_range(0..30);
699        let buffer = if rng.gen() {
700            let text = util::RandomCharIter::new(&mut rng)
701                .take(len)
702                .collect::<String>();
703            MultiBuffer::build_simple(&text, cx)
704        } else {
705            MultiBuffer::build_random(&mut rng, cx)
706        };
707        let buffer_snapshot = buffer.read(cx).snapshot(cx);
708        log::info!("Buffer text: {:?}", buffer_snapshot.text());
709
710        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
711        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
712        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
713        fold_map.randomly_mutate(&mut rng);
714        let (fold_snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
715        log::info!("FoldMap text: {:?}", fold_snapshot.text());
716        let (inlay_snapshot, _) = inlay_map.randomly_mutate(&mut 0, &mut rng);
717        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
718
719        let (mut tab_map, _) = TabMap::new(fold_snapshot.clone(), tab_size);
720        let tabs_snapshot = tab_map.set_max_expansion_column(32);
721
722        let text = text::Rope::from(tabs_snapshot.text().as_str());
723        log::info!(
724            "TabMap text (tab size: {}): {:?}",
725            tab_size,
726            tabs_snapshot.text(),
727        );
728
729        for _ in 0..5 {
730            let end_row = rng.gen_range(0..=text.max_point().row);
731            let end_column = rng.gen_range(0..=text.line_len(end_row));
732            let mut end = TabPoint(text.clip_point(Point::new(end_row, end_column), Bias::Right));
733            let start_row = rng.gen_range(0..=text.max_point().row);
734            let start_column = rng.gen_range(0..=text.line_len(start_row));
735            let mut start =
736                TabPoint(text.clip_point(Point::new(start_row, start_column), Bias::Left));
737            if start > end {
738                mem::swap(&mut start, &mut end);
739            }
740
741            let expected_text = text
742                .chunks_in_range(text.point_to_offset(start.0)..text.point_to_offset(end.0))
743                .collect::<String>();
744            let expected_summary = TextSummary::from(expected_text.as_str());
745            assert_eq!(
746                tabs_snapshot
747                    .chunks(start..end, false, None, None, None)
748                    .map(|c| c.text)
749                    .collect::<String>(),
750                expected_text,
751                "chunks({:?}..{:?})",
752                start,
753                end
754            );
755
756            let mut actual_summary = tabs_snapshot.text_summary_for_range(start..end);
757            if tab_size.get() > 1 && inlay_snapshot.text().contains('\t') {
758                actual_summary.longest_row = expected_summary.longest_row;
759                actual_summary.longest_row_chars = expected_summary.longest_row_chars;
760            }
761            assert_eq!(actual_summary, expected_summary);
762        }
763
764        for row in 0..=text.max_point().row {
765            assert_eq!(
766                tabs_snapshot.line_len(row),
767                text.line_len(row),
768                "line_len({row})"
769            );
770        }
771    }
772}