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 fold_edits = fold_edits.into_iter();
108            let fold_edits = if let Some(mut first_edit) = fold_edits.next() {
109                let mut v: Vec<_> = fold_edits
110                    .scan(&mut first_edit, |state, edit| {
111                        if state.old.end >= edit.old.start {
112                            state.old.end = edit.old.end;
113                            state.new.end = edit.new.end;
114                            Some(None) // Skip this edit, it's merged
115                        } else {
116                            let new_state = edit.clone();
117                            let result = Some(Some(state.clone())); // Yield the previous edit
118                            **state = new_state;
119                            result
120                        }
121                    })
122                    .flatten()
123                    .collect();
124                v.push(first_edit);
125
126                v
127            } else {
128                vec![]
129            };
130
131            for fold_edit in fold_edits {
132                let old_start = fold_edit.old.start.to_point(&old_snapshot.fold_snapshot);
133                let old_end = fold_edit.old.end.to_point(&old_snapshot.fold_snapshot);
134                let new_start = fold_edit.new.start.to_point(&new_snapshot.fold_snapshot);
135                let new_end = fold_edit.new.end.to_point(&new_snapshot.fold_snapshot);
136                tab_edits.push(TabEdit {
137                    old: old_snapshot.to_tab_point(old_start)..old_snapshot.to_tab_point(old_end),
138                    new: new_snapshot.to_tab_point(new_start)..new_snapshot.to_tab_point(new_end),
139                });
140            }
141        } else {
142            new_snapshot.version += 1;
143            tab_edits.push(TabEdit {
144                old: TabPoint::zero()..old_snapshot.max_point(),
145                new: TabPoint::zero()..new_snapshot.max_point(),
146            });
147        }
148
149        *old_snapshot = new_snapshot;
150        (old_snapshot.clone(), tab_edits)
151    }
152}
153
154#[derive(Clone)]
155pub struct TabSnapshot {
156    pub fold_snapshot: FoldSnapshot,
157    pub tab_size: NonZeroU32,
158    pub max_expansion_column: u32,
159    pub version: usize,
160}
161
162impl TabSnapshot {
163    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
164        &self.fold_snapshot.inlay_snapshot.buffer
165    }
166
167    pub fn line_len(&self, row: u32) -> u32 {
168        let max_point = self.max_point();
169        if row < max_point.row() {
170            self.to_tab_point(FoldPoint::new(row, self.fold_snapshot.line_len(row)))
171                .0
172                .column
173        } else {
174            max_point.column()
175        }
176    }
177
178    pub fn text_summary(&self) -> TextSummary {
179        self.text_summary_for_range(TabPoint::zero()..self.max_point())
180    }
181
182    pub fn text_summary_for_range(&self, range: Range<TabPoint>) -> TextSummary {
183        let input_start = self.to_fold_point(range.start, Bias::Left).0;
184        let input_end = self.to_fold_point(range.end, Bias::Right).0;
185        let input_summary = self
186            .fold_snapshot
187            .text_summary_for_range(input_start..input_end);
188
189        let mut first_line_chars = 0;
190        let line_end = if range.start.row() == range.end.row() {
191            range.end
192        } else {
193            self.max_point()
194        };
195        for c in self
196            .chunks(range.start..line_end, false, Highlights::default())
197            .flat_map(|chunk| chunk.text.chars())
198        {
199            if c == '\n' {
200                break;
201            }
202            first_line_chars += 1;
203        }
204
205        let mut last_line_chars = 0;
206        if range.start.row() == range.end.row() {
207            last_line_chars = first_line_chars;
208        } else {
209            for _ in self
210                .chunks(
211                    TabPoint::new(range.end.row(), 0)..range.end,
212                    false,
213                    Highlights::default(),
214                )
215                .flat_map(|chunk| chunk.text.chars())
216            {
217                last_line_chars += 1;
218            }
219        }
220
221        TextSummary {
222            lines: range.end.0 - range.start.0,
223            first_line_chars,
224            last_line_chars,
225            longest_row: input_summary.longest_row,
226            longest_row_chars: input_summary.longest_row_chars,
227        }
228    }
229
230    pub fn chunks<'a>(
231        &'a self,
232        range: Range<TabPoint>,
233        language_aware: bool,
234        highlights: Highlights<'a>,
235    ) -> TabChunks<'a> {
236        let (input_start, expanded_char_column, to_next_stop) =
237            self.to_fold_point(range.start, Bias::Left);
238        let input_column = input_start.column();
239        let input_start = input_start.to_offset(&self.fold_snapshot);
240        let input_end = self
241            .to_fold_point(range.end, Bias::Right)
242            .0
243            .to_offset(&self.fold_snapshot);
244        let to_next_stop = if range.start.0 + Point::new(0, to_next_stop) > range.end.0 {
245            range.end.column() - range.start.column()
246        } else {
247            to_next_stop
248        };
249
250        TabChunks {
251            fold_chunks: self.fold_snapshot.chunks(
252                input_start..input_end,
253                language_aware,
254                highlights,
255            ),
256            input_column,
257            column: expanded_char_column,
258            max_expansion_column: self.max_expansion_column,
259            output_position: range.start.0,
260            max_output_position: range.end.0,
261            tab_size: self.tab_size,
262            chunk: Chunk {
263                text: &SPACES[0..(to_next_stop as usize)],
264                is_tab: true,
265                ..Default::default()
266            },
267            inside_leading_tab: to_next_stop > 0,
268        }
269    }
270
271    pub fn buffer_rows(&self, row: u32) -> fold_map::FoldBufferRows<'_> {
272        self.fold_snapshot.buffer_rows(row)
273    }
274
275    #[cfg(test)]
276    pub fn text(&self) -> String {
277        self.chunks(
278            TabPoint::zero()..self.max_point(),
279            false,
280            Highlights::default(),
281        )
282        .map(|chunk| chunk.text)
283        .collect()
284    }
285
286    pub fn max_point(&self) -> TabPoint {
287        self.to_tab_point(self.fold_snapshot.max_point())
288    }
289
290    pub fn clip_point(&self, point: TabPoint, bias: Bias) -> TabPoint {
291        self.to_tab_point(
292            self.fold_snapshot
293                .clip_point(self.to_fold_point(point, bias).0, bias),
294        )
295    }
296
297    pub fn to_tab_point(&self, input: FoldPoint) -> TabPoint {
298        let chars = self.fold_snapshot.chars_at(FoldPoint::new(input.row(), 0));
299        let expanded = self.expand_tabs(chars, input.column());
300        TabPoint::new(input.row(), expanded)
301    }
302
303    pub fn to_fold_point(&self, output: TabPoint, bias: Bias) -> (FoldPoint, u32, u32) {
304        let chars = self.fold_snapshot.chars_at(FoldPoint::new(output.row(), 0));
305        let expanded = output.column();
306        let (collapsed, expanded_char_column, to_next_stop) =
307            self.collapse_tabs(chars, expanded, bias);
308        (
309            FoldPoint::new(output.row(), collapsed),
310            expanded_char_column,
311            to_next_stop,
312        )
313    }
314
315    pub fn make_tab_point(&self, point: Point, bias: Bias) -> TabPoint {
316        let inlay_point = self.fold_snapshot.inlay_snapshot.to_inlay_point(point);
317        let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
318        self.to_tab_point(fold_point)
319    }
320
321    pub fn to_point(&self, point: TabPoint, bias: Bias) -> Point {
322        let fold_point = self.to_fold_point(point, bias).0;
323        let inlay_point = fold_point.to_inlay_point(&self.fold_snapshot);
324        self.fold_snapshot
325            .inlay_snapshot
326            .to_buffer_point(inlay_point)
327    }
328
329    fn expand_tabs(&self, chars: impl Iterator<Item = char>, column: u32) -> u32 {
330        let tab_size = self.tab_size.get();
331
332        let mut expanded_chars = 0;
333        let mut expanded_bytes = 0;
334        let mut collapsed_bytes = 0;
335        let end_column = column.min(self.max_expansion_column);
336        for c in chars {
337            if collapsed_bytes >= end_column {
338                break;
339            }
340            if c == '\t' {
341                let tab_len = tab_size - expanded_chars % tab_size;
342                expanded_bytes += tab_len;
343                expanded_chars += tab_len;
344            } else {
345                expanded_bytes += c.len_utf8() as u32;
346                expanded_chars += 1;
347            }
348            collapsed_bytes += c.len_utf8() as u32;
349        }
350        expanded_bytes + column.saturating_sub(collapsed_bytes)
351    }
352
353    fn collapse_tabs(
354        &self,
355        chars: impl Iterator<Item = char>,
356        column: u32,
357        bias: Bias,
358    ) -> (u32, u32, u32) {
359        let tab_size = self.tab_size.get();
360
361        let mut expanded_bytes = 0;
362        let mut expanded_chars = 0;
363        let mut collapsed_bytes = 0;
364        for c in chars {
365            if expanded_bytes >= column {
366                break;
367            }
368            if collapsed_bytes >= self.max_expansion_column {
369                break;
370            }
371
372            if c == '\t' {
373                let tab_len = tab_size - (expanded_chars % tab_size);
374                expanded_chars += tab_len;
375                expanded_bytes += tab_len;
376                if expanded_bytes > column {
377                    expanded_chars -= expanded_bytes - column;
378                    return match bias {
379                        Bias::Left => (collapsed_bytes, expanded_chars, expanded_bytes - column),
380                        Bias::Right => (collapsed_bytes + 1, expanded_chars, 0),
381                    };
382                }
383            } else {
384                expanded_chars += 1;
385                expanded_bytes += c.len_utf8() as u32;
386            }
387
388            if expanded_bytes > column && matches!(bias, Bias::Left) {
389                expanded_chars -= 1;
390                break;
391            }
392
393            collapsed_bytes += c.len_utf8() as u32;
394        }
395        (
396            collapsed_bytes + column.saturating_sub(expanded_bytes),
397            expanded_chars,
398            0,
399        )
400    }
401}
402
403#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
404pub struct TabPoint(pub Point);
405
406impl TabPoint {
407    pub fn new(row: u32, column: u32) -> Self {
408        Self(Point::new(row, column))
409    }
410
411    pub fn zero() -> Self {
412        Self::new(0, 0)
413    }
414
415    pub fn row(self) -> u32 {
416        self.0.row
417    }
418
419    pub fn column(self) -> u32 {
420        self.0.column
421    }
422}
423
424impl From<Point> for TabPoint {
425    fn from(point: Point) -> Self {
426        Self(point)
427    }
428}
429
430pub type TabEdit = text::Edit<TabPoint>;
431
432#[derive(Clone, Debug, Default, Eq, PartialEq)]
433pub struct TextSummary {
434    pub lines: Point,
435    pub first_line_chars: u32,
436    pub last_line_chars: u32,
437    pub longest_row: u32,
438    pub longest_row_chars: u32,
439}
440
441impl<'a> From<&'a str> for TextSummary {
442    fn from(text: &'a str) -> Self {
443        let sum = text::TextSummary::from(text);
444
445        TextSummary {
446            lines: sum.lines,
447            first_line_chars: sum.first_line_chars,
448            last_line_chars: sum.last_line_chars,
449            longest_row: sum.longest_row,
450            longest_row_chars: sum.longest_row_chars,
451        }
452    }
453}
454
455impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
456    fn add_assign(&mut self, other: &'a Self) {
457        let joined_chars = self.last_line_chars + other.first_line_chars;
458        if joined_chars > self.longest_row_chars {
459            self.longest_row = self.lines.row;
460            self.longest_row_chars = joined_chars;
461        }
462        if other.longest_row_chars > self.longest_row_chars {
463            self.longest_row = self.lines.row + other.longest_row;
464            self.longest_row_chars = other.longest_row_chars;
465        }
466
467        if self.lines.row == 0 {
468            self.first_line_chars += other.first_line_chars;
469        }
470
471        if other.lines.row == 0 {
472            self.last_line_chars += other.first_line_chars;
473        } else {
474            self.last_line_chars = other.last_line_chars;
475        }
476
477        self.lines += &other.lines;
478    }
479}
480
481// Handles a tab width <= 16
482const SPACES: &str = "                ";
483
484pub struct TabChunks<'a> {
485    fold_chunks: FoldChunks<'a>,
486    chunk: Chunk<'a>,
487    column: u32,
488    max_expansion_column: u32,
489    output_position: Point,
490    input_column: u32,
491    max_output_position: Point,
492    tab_size: NonZeroU32,
493    inside_leading_tab: bool,
494}
495
496impl<'a> Iterator for TabChunks<'a> {
497    type Item = Chunk<'a>;
498
499    fn next(&mut self) -> Option<Self::Item> {
500        if self.chunk.text.is_empty() {
501            if let Some(chunk) = self.fold_chunks.next() {
502                self.chunk = chunk;
503                if self.inside_leading_tab {
504                    self.chunk.text = &self.chunk.text[1..];
505                    self.inside_leading_tab = false;
506                    self.input_column += 1;
507                }
508            } else {
509                return None;
510            }
511        }
512
513        for (ix, c) in self.chunk.text.char_indices() {
514            match c {
515                '\t' => {
516                    if ix > 0 {
517                        let (prefix, suffix) = self.chunk.text.split_at(ix);
518                        self.chunk.text = suffix;
519                        return Some(Chunk {
520                            text: prefix,
521                            ..self.chunk.clone()
522                        });
523                    } else {
524                        self.chunk.text = &self.chunk.text[1..];
525                        let tab_size = if self.input_column < self.max_expansion_column {
526                            self.tab_size.get()
527                        } else {
528                            1
529                        };
530                        let mut len = tab_size - self.column % tab_size;
531                        let next_output_position = cmp::min(
532                            self.output_position + Point::new(0, len),
533                            self.max_output_position,
534                        );
535                        len = next_output_position.column - self.output_position.column;
536                        self.column += len;
537                        self.input_column += 1;
538                        self.output_position = next_output_position;
539                        return Some(Chunk {
540                            text: &SPACES[..len as usize],
541                            is_tab: true,
542                            ..self.chunk.clone()
543                        });
544                    }
545                }
546                '\n' => {
547                    self.column = 0;
548                    self.input_column = 0;
549                    self.output_position += Point::new(1, 0);
550                }
551                _ => {
552                    self.column += 1;
553                    if !self.inside_leading_tab {
554                        self.input_column += c.len_utf8() as u32;
555                    }
556                    self.output_position.column += c.len_utf8() as u32;
557                }
558            }
559        }
560
561        Some(mem::take(&mut self.chunk))
562    }
563}
564
565#[cfg(test)]
566mod tests {
567    use super::*;
568    use crate::{
569        display_map::{fold_map::FoldMap, inlay_map::InlayMap},
570        MultiBuffer,
571    };
572    use rand::{prelude::StdRng, Rng};
573
574    #[gpui::test]
575    fn test_expand_tabs(cx: &mut gpui::AppContext) {
576        let buffer = MultiBuffer::build_simple("", cx);
577        let buffer_snapshot = buffer.read(cx).snapshot(cx);
578        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
579        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
580        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
581
582        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 0), 0);
583        assert_eq!(tab_snapshot.expand_tabs("\t".chars(), 1), 4);
584        assert_eq!(tab_snapshot.expand_tabs("\ta".chars(), 2), 5);
585    }
586
587    #[gpui::test]
588    fn test_long_lines(cx: &mut gpui::AppContext) {
589        let max_expansion_column = 12;
590        let input = "A\tBC\tDEF\tG\tHI\tJ\tK\tL\tM";
591        let output = "A   BC  DEF G   HI J K L M";
592
593        let buffer = MultiBuffer::build_simple(input, cx);
594        let buffer_snapshot = buffer.read(cx).snapshot(cx);
595        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
596        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
597        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
598
599        tab_snapshot.max_expansion_column = max_expansion_column;
600        assert_eq!(tab_snapshot.text(), output);
601
602        for (ix, c) in input.char_indices() {
603            assert_eq!(
604                tab_snapshot
605                    .chunks(
606                        TabPoint::new(0, ix as u32)..tab_snapshot.max_point(),
607                        false,
608                        Highlights::default(),
609                    )
610                    .map(|c| c.text)
611                    .collect::<String>(),
612                &output[ix..],
613                "text from index {ix}"
614            );
615
616            if c != '\t' {
617                let input_point = Point::new(0, ix as u32);
618                let output_point = Point::new(0, output.find(c).unwrap() as u32);
619                assert_eq!(
620                    tab_snapshot.to_tab_point(FoldPoint(input_point)),
621                    TabPoint(output_point),
622                    "to_tab_point({input_point:?})"
623                );
624                assert_eq!(
625                    tab_snapshot
626                        .to_fold_point(TabPoint(output_point), Bias::Left)
627                        .0,
628                    FoldPoint(input_point),
629                    "to_fold_point({output_point:?})"
630                );
631            }
632        }
633    }
634
635    #[gpui::test]
636    fn test_long_lines_with_character_spanning_max_expansion_column(cx: &mut gpui::AppContext) {
637        let max_expansion_column = 8;
638        let input = "abcdefg⋯hij";
639
640        let buffer = MultiBuffer::build_simple(input, cx);
641        let buffer_snapshot = buffer.read(cx).snapshot(cx);
642        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
643        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
644        let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
645
646        tab_snapshot.max_expansion_column = max_expansion_column;
647        assert_eq!(tab_snapshot.text(), input);
648    }
649
650    #[gpui::test]
651    fn test_marking_tabs(cx: &mut gpui::AppContext) {
652        let input = "\t \thello";
653
654        let buffer = MultiBuffer::build_simple(&input, cx);
655        let buffer_snapshot = buffer.read(cx).snapshot(cx);
656        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
657        let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
658        let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
659
660        assert_eq!(
661            chunks(&tab_snapshot, TabPoint::zero()),
662            vec![
663                ("    ".to_string(), true),
664                (" ".to_string(), false),
665                ("   ".to_string(), true),
666                ("hello".to_string(), false),
667            ]
668        );
669        assert_eq!(
670            chunks(&tab_snapshot, TabPoint::new(0, 2)),
671            vec![
672                ("  ".to_string(), true),
673                (" ".to_string(), false),
674                ("   ".to_string(), true),
675                ("hello".to_string(), false),
676            ]
677        );
678
679        fn chunks(snapshot: &TabSnapshot, start: TabPoint) -> Vec<(String, bool)> {
680            let mut chunks = Vec::new();
681            let mut was_tab = false;
682            let mut text = String::new();
683            for chunk in snapshot.chunks(start..snapshot.max_point(), false, Highlights::default())
684            {
685                if chunk.is_tab != was_tab {
686                    if !text.is_empty() {
687                        chunks.push((mem::take(&mut text), was_tab));
688                    }
689                    was_tab = chunk.is_tab;
690                }
691                text.push_str(chunk.text);
692            }
693
694            if !text.is_empty() {
695                chunks.push((text, was_tab));
696            }
697            chunks
698        }
699    }
700
701    #[gpui::test(iterations = 100)]
702    fn test_random_tabs(cx: &mut gpui::AppContext, mut rng: StdRng) {
703        let tab_size = NonZeroU32::new(rng.gen_range(1..=4)).unwrap();
704        let len = rng.gen_range(0..30);
705        let buffer = if rng.gen() {
706            let text = util::RandomCharIter::new(&mut rng)
707                .take(len)
708                .collect::<String>();
709            MultiBuffer::build_simple(&text, cx)
710        } else {
711            MultiBuffer::build_random(&mut rng, cx)
712        };
713        let buffer_snapshot = buffer.read(cx).snapshot(cx);
714        log::info!("Buffer text: {:?}", buffer_snapshot.text());
715
716        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
717        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
718        let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
719        fold_map.randomly_mutate(&mut rng);
720        let (fold_snapshot, _) = fold_map.read(inlay_snapshot, vec![]);
721        log::info!("FoldMap text: {:?}", fold_snapshot.text());
722        let (inlay_snapshot, _) = inlay_map.randomly_mutate(&mut 0, &mut rng);
723        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
724
725        let (mut tab_map, _) = TabMap::new(fold_snapshot.clone(), tab_size);
726        let tabs_snapshot = tab_map.set_max_expansion_column(32);
727
728        let text = text::Rope::from(tabs_snapshot.text().as_str());
729        log::info!(
730            "TabMap text (tab size: {}): {:?}",
731            tab_size,
732            tabs_snapshot.text(),
733        );
734
735        for _ in 0..5 {
736            let end_row = rng.gen_range(0..=text.max_point().row);
737            let end_column = rng.gen_range(0..=text.line_len(end_row));
738            let mut end = TabPoint(text.clip_point(Point::new(end_row, end_column), Bias::Right));
739            let start_row = rng.gen_range(0..=text.max_point().row);
740            let start_column = rng.gen_range(0..=text.line_len(start_row));
741            let mut start =
742                TabPoint(text.clip_point(Point::new(start_row, start_column), Bias::Left));
743            if start > end {
744                mem::swap(&mut start, &mut end);
745            }
746
747            let expected_text = text
748                .chunks_in_range(text.point_to_offset(start.0)..text.point_to_offset(end.0))
749                .collect::<String>();
750            let expected_summary = TextSummary::from(expected_text.as_str());
751            assert_eq!(
752                tabs_snapshot
753                    .chunks(start..end, false, Highlights::default())
754                    .map(|c| c.text)
755                    .collect::<String>(),
756                expected_text,
757                "chunks({:?}..{:?})",
758                start,
759                end
760            );
761
762            let mut actual_summary = tabs_snapshot.text_summary_for_range(start..end);
763            if tab_size.get() > 1 && inlay_snapshot.text().contains('\t') {
764                actual_summary.longest_row = expected_summary.longest_row;
765                actual_summary.longest_row_chars = expected_summary.longest_row_chars;
766            }
767            assert_eq!(actual_summary, expected_summary);
768        }
769
770        for row in 0..=text.max_point().row {
771            assert_eq!(
772                tabs_snapshot.line_len(row),
773                text.line_len(row),
774                "line_len({row})"
775            );
776        }
777    }
778}