1use super::{
  2    fold_map::{self, FoldEdit, FoldPoint, FoldSnapshot},
  3    TextHighlights,
  4};
  5use crate::MultiBufferSnapshot;
  6use language::{Chunk, Point};
  7use parking_lot::Mutex;
  8use std::{cmp, mem, num::NonZeroU32, ops::Range};
  9use sum_tree::Bias;
 10
 11pub struct TabMap(Mutex<TabSnapshot>);
 12
 13impl TabMap {
 14    pub fn new(input: FoldSnapshot, tab_size: NonZeroU32) -> (Self, TabSnapshot) {
 15        let snapshot = TabSnapshot {
 16            fold_snapshot: input,
 17            tab_size,
 18            version: 0,
 19        };
 20        (Self(Mutex::new(snapshot.clone())), snapshot)
 21    }
 22
 23    pub fn sync(
 24        &self,
 25        fold_snapshot: FoldSnapshot,
 26        mut fold_edits: Vec<FoldEdit>,
 27        tab_size: NonZeroU32,
 28    ) -> (TabSnapshot, Vec<TabEdit>) {
 29        let mut old_snapshot = self.0.lock();
 30        let mut new_snapshot = TabSnapshot {
 31            fold_snapshot,
 32            tab_size,
 33            version: old_snapshot.version,
 34        };
 35
 36        if old_snapshot.fold_snapshot.version != new_snapshot.fold_snapshot.version {
 37            new_snapshot.version += 1;
 38        }
 39
 40        let old_max_offset = old_snapshot.fold_snapshot.len();
 41        let mut tab_edits = Vec::with_capacity(fold_edits.len());
 42
 43        if old_snapshot.tab_size == new_snapshot.tab_size {
 44            for fold_edit in &mut fold_edits {
 45                let mut delta = 0;
 46                for chunk in old_snapshot.fold_snapshot.chunks(
 47                    fold_edit.old.end..old_max_offset,
 48                    false,
 49                    None,
 50                ) {
 51                    let patterns: &[_] = &['\t', '\n'];
 52                    if let Some(ix) = chunk.text.find(patterns) {
 53                        if &chunk.text[ix..ix + 1] == "\t" {
 54                            fold_edit.old.end.0 += delta + ix + 1;
 55                            fold_edit.new.end.0 += delta + ix + 1;
 56                        }
 57
 58                        break;
 59                    }
 60
 61                    delta += chunk.text.len();
 62                }
 63            }
 64
 65            let mut ix = 1;
 66            while ix < fold_edits.len() {
 67                let (prev_edits, next_edits) = fold_edits.split_at_mut(ix);
 68                let prev_edit = prev_edits.last_mut().unwrap();
 69                let edit = &next_edits[0];
 70                if prev_edit.old.end >= edit.old.start {
 71                    prev_edit.old.end = edit.old.end;
 72                    prev_edit.new.end = edit.new.end;
 73                    fold_edits.remove(ix);
 74                } else {
 75                    ix += 1;
 76                }
 77            }
 78
 79            for fold_edit in fold_edits {
 80                let old_start = fold_edit.old.start.to_point(&old_snapshot.fold_snapshot);
 81                let old_end = fold_edit.old.end.to_point(&old_snapshot.fold_snapshot);
 82                let new_start = fold_edit.new.start.to_point(&new_snapshot.fold_snapshot);
 83                let new_end = fold_edit.new.end.to_point(&new_snapshot.fold_snapshot);
 84                tab_edits.push(TabEdit {
 85                    old: old_snapshot.to_tab_point(old_start)..old_snapshot.to_tab_point(old_end),
 86                    new: new_snapshot.to_tab_point(new_start)..new_snapshot.to_tab_point(new_end),
 87                });
 88            }
 89        } else {
 90            new_snapshot.version += 1;
 91            tab_edits.push(TabEdit {
 92                old: TabPoint::zero()..old_snapshot.max_point(),
 93                new: TabPoint::zero()..new_snapshot.max_point(),
 94            });
 95        }
 96
 97        *old_snapshot = new_snapshot;
 98        (old_snapshot.clone(), tab_edits)
 99    }
100}
101
102#[derive(Clone)]
103pub struct TabSnapshot {
104    pub fold_snapshot: FoldSnapshot,
105    pub tab_size: NonZeroU32,
106    pub version: usize,
107}
108
109impl TabSnapshot {
110    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
111        self.fold_snapshot.buffer_snapshot()
112    }
113
114    pub fn line_len(&self, row: u32) -> u32 {
115        let max_point = self.max_point();
116        if row < max_point.row() {
117            self.chunks(
118                TabPoint::new(row, 0)..TabPoint::new(row + 1, 0),
119                false,
120                None,
121            )
122            .map(|chunk| chunk.text.len() as u32)
123            .sum::<u32>()
124                - 1
125        } else {
126            max_point.column()
127        }
128    }
129
130    pub fn text_summary(&self) -> TextSummary {
131        self.text_summary_for_range(TabPoint::zero()..self.max_point())
132    }
133
134    pub fn text_summary_for_range(&self, range: Range<TabPoint>) -> TextSummary {
135        let input_start = self.to_fold_point(range.start, Bias::Left).0;
136        let input_end = self.to_fold_point(range.end, Bias::Right).0;
137        let input_summary = self
138            .fold_snapshot
139            .text_summary_for_range(input_start..input_end);
140
141        let mut first_line_chars = 0;
142        let line_end = if range.start.row() == range.end.row() {
143            range.end
144        } else {
145            self.max_point()
146        };
147        for c in self
148            .chunks(range.start..line_end, false, None)
149            .flat_map(|chunk| chunk.text.chars())
150        {
151            if c == '\n' {
152                break;
153            }
154            first_line_chars += 1;
155        }
156
157        let mut last_line_chars = 0;
158        if range.start.row() == range.end.row() {
159            last_line_chars = first_line_chars;
160        } else {
161            for _ in self
162                .chunks(TabPoint::new(range.end.row(), 0)..range.end, false, None)
163                .flat_map(|chunk| chunk.text.chars())
164            {
165                last_line_chars += 1;
166            }
167        }
168
169        TextSummary {
170            lines: range.end.0 - range.start.0,
171            first_line_chars,
172            last_line_chars,
173            longest_row: input_summary.longest_row,
174            longest_row_chars: input_summary.longest_row_chars,
175        }
176    }
177
178    pub fn chunks<'a>(
179        &'a self,
180        range: Range<TabPoint>,
181        language_aware: bool,
182        text_highlights: Option<&'a TextHighlights>,
183    ) -> TabChunks<'a> {
184        let (input_start, expanded_char_column, to_next_stop) =
185            self.to_fold_point(range.start, Bias::Left);
186        let input_start = input_start.to_offset(&self.fold_snapshot);
187        let input_end = self
188            .to_fold_point(range.end, Bias::Right)
189            .0
190            .to_offset(&self.fold_snapshot);
191        let to_next_stop = if range.start.0 + Point::new(0, to_next_stop as u32) > range.end.0 {
192            (range.end.column() - range.start.column()) as usize
193        } else {
194            to_next_stop
195        };
196
197        TabChunks {
198            fold_chunks: self.fold_snapshot.chunks(
199                input_start..input_end,
200                language_aware,
201                text_highlights,
202            ),
203            column: expanded_char_column,
204            output_position: range.start.0,
205            max_output_position: range.end.0,
206            tab_size: self.tab_size,
207            chunk: Chunk {
208                text: &SPACES[0..to_next_stop],
209                ..Default::default()
210            },
211            skip_leading_tab: to_next_stop > 0,
212        }
213    }
214
215    pub fn buffer_rows(&self, row: u32) -> fold_map::FoldBufferRows {
216        self.fold_snapshot.buffer_rows(row)
217    }
218
219    #[cfg(test)]
220    pub fn text(&self) -> String {
221        self.chunks(TabPoint::zero()..self.max_point(), false, None)
222            .map(|chunk| chunk.text)
223            .collect()
224    }
225
226    pub fn max_point(&self) -> TabPoint {
227        self.to_tab_point(self.fold_snapshot.max_point())
228    }
229
230    pub fn clip_point(&self, point: TabPoint, bias: Bias) -> TabPoint {
231        self.to_tab_point(
232            self.fold_snapshot
233                .clip_point(self.to_fold_point(point, bias).0, bias),
234        )
235    }
236
237    pub fn to_tab_point(&self, input: FoldPoint) -> TabPoint {
238        let chars = self.fold_snapshot.chars_at(FoldPoint::new(input.row(), 0));
239        let expanded = Self::expand_tabs(chars, input.column() as usize, self.tab_size);
240        TabPoint::new(input.row(), expanded as u32)
241    }
242
243    pub fn to_fold_point(&self, output: TabPoint, bias: Bias) -> (FoldPoint, usize, usize) {
244        let chars = self.fold_snapshot.chars_at(FoldPoint::new(output.row(), 0));
245        let expanded = output.column() as usize;
246        let (collapsed, expanded_char_column, to_next_stop) =
247            Self::collapse_tabs(chars, expanded, bias, self.tab_size);
248        (
249            FoldPoint::new(output.row(), collapsed as u32),
250            expanded_char_column,
251            to_next_stop,
252        )
253    }
254
255    pub fn make_tab_point(&self, point: Point, bias: Bias) -> TabPoint {
256        self.to_tab_point(self.fold_snapshot.to_fold_point(point, bias))
257    }
258
259    pub fn to_point(&self, point: TabPoint, bias: Bias) -> Point {
260        self.to_fold_point(point, bias)
261            .0
262            .to_buffer_point(&self.fold_snapshot)
263    }
264
265    fn expand_tabs(
266        chars: impl Iterator<Item = char>,
267        column: usize,
268        tab_size: NonZeroU32,
269    ) -> usize {
270        let mut expanded_chars = 0;
271        let mut expanded_bytes = 0;
272        let mut collapsed_bytes = 0;
273        for c in chars {
274            if collapsed_bytes == column {
275                break;
276            }
277            if c == '\t' {
278                let tab_size = tab_size.get() as usize;
279                let tab_len = tab_size - expanded_chars % tab_size;
280                expanded_bytes += tab_len;
281                expanded_chars += tab_len;
282            } else {
283                expanded_bytes += c.len_utf8();
284                expanded_chars += 1;
285            }
286            collapsed_bytes += c.len_utf8();
287        }
288        expanded_bytes
289    }
290
291    fn collapse_tabs(
292        chars: impl Iterator<Item = char>,
293        column: usize,
294        bias: Bias,
295        tab_size: NonZeroU32,
296    ) -> (usize, usize, usize) {
297        let mut expanded_bytes = 0;
298        let mut expanded_chars = 0;
299        let mut collapsed_bytes = 0;
300        for c in chars {
301            if expanded_bytes >= column {
302                break;
303            }
304
305            if c == '\t' {
306                let tab_size = tab_size.get() as usize;
307                let tab_len = tab_size - (expanded_chars % tab_size);
308                expanded_chars += tab_len;
309                expanded_bytes += tab_len;
310                if expanded_bytes > column {
311                    expanded_chars -= expanded_bytes - column;
312                    return match bias {
313                        Bias::Left => (collapsed_bytes, expanded_chars, expanded_bytes - column),
314                        Bias::Right => (collapsed_bytes + 1, expanded_chars, 0),
315                    };
316                }
317            } else {
318                expanded_chars += 1;
319                expanded_bytes += c.len_utf8();
320            }
321
322            if expanded_bytes > column && matches!(bias, Bias::Left) {
323                expanded_chars -= 1;
324                break;
325            }
326
327            collapsed_bytes += c.len_utf8();
328        }
329        (collapsed_bytes, expanded_chars, 0)
330    }
331}
332
333#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
334pub struct TabPoint(pub Point);
335
336impl TabPoint {
337    pub fn new(row: u32, column: u32) -> Self {
338        Self(Point::new(row, column))
339    }
340
341    pub fn zero() -> Self {
342        Self::new(0, 0)
343    }
344
345    pub fn row(self) -> u32 {
346        self.0.row
347    }
348
349    pub fn column(self) -> u32 {
350        self.0.column
351    }
352}
353
354impl From<Point> for TabPoint {
355    fn from(point: Point) -> Self {
356        Self(point)
357    }
358}
359
360pub type TabEdit = text::Edit<TabPoint>;
361
362#[derive(Clone, Debug, Default, Eq, PartialEq)]
363pub struct TextSummary {
364    pub lines: Point,
365    pub first_line_chars: u32,
366    pub last_line_chars: u32,
367    pub longest_row: u32,
368    pub longest_row_chars: u32,
369}
370
371impl<'a> From<&'a str> for TextSummary {
372    fn from(text: &'a str) -> Self {
373        let sum = text::TextSummary::from(text);
374
375        TextSummary {
376            lines: sum.lines,
377            first_line_chars: sum.first_line_chars,
378            last_line_chars: sum.last_line_chars,
379            longest_row: sum.longest_row,
380            longest_row_chars: sum.longest_row_chars,
381        }
382    }
383}
384
385impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
386    fn add_assign(&mut self, other: &'a Self) {
387        let joined_chars = self.last_line_chars + other.first_line_chars;
388        if joined_chars > self.longest_row_chars {
389            self.longest_row = self.lines.row;
390            self.longest_row_chars = joined_chars;
391        }
392        if other.longest_row_chars > self.longest_row_chars {
393            self.longest_row = self.lines.row + other.longest_row;
394            self.longest_row_chars = other.longest_row_chars;
395        }
396
397        if self.lines.row == 0 {
398            self.first_line_chars += other.first_line_chars;
399        }
400
401        if other.lines.row == 0 {
402            self.last_line_chars += other.first_line_chars;
403        } else {
404            self.last_line_chars = other.last_line_chars;
405        }
406
407        self.lines += &other.lines;
408    }
409}
410
411// Handles a tab width <= 16
412const SPACES: &str = "                ";
413
414pub struct TabChunks<'a> {
415    fold_chunks: fold_map::FoldChunks<'a>,
416    chunk: Chunk<'a>,
417    column: usize,
418    output_position: Point,
419    max_output_position: Point,
420    tab_size: NonZeroU32,
421    skip_leading_tab: bool,
422}
423
424impl<'a> Iterator for TabChunks<'a> {
425    type Item = Chunk<'a>;
426
427    fn next(&mut self) -> Option<Self::Item> {
428        if self.chunk.text.is_empty() {
429            if let Some(chunk) = self.fold_chunks.next() {
430                self.chunk = chunk;
431                if self.skip_leading_tab {
432                    self.chunk.text = &self.chunk.text[1..];
433                    self.skip_leading_tab = false;
434                }
435            } else {
436                return None;
437            }
438        }
439
440        for (ix, c) in self.chunk.text.char_indices() {
441            match c {
442                '\t' => {
443                    if ix > 0 {
444                        let (prefix, suffix) = self.chunk.text.split_at(ix);
445                        self.chunk.text = suffix;
446                        return Some(Chunk {
447                            text: prefix,
448                            ..self.chunk
449                        });
450                    } else {
451                        self.chunk.text = &self.chunk.text[1..];
452                        let tab_size = self.tab_size.get() as u32;
453                        let mut len = tab_size - self.column as u32 % tab_size;
454                        let next_output_position = cmp::min(
455                            self.output_position + Point::new(0, len),
456                            self.max_output_position,
457                        );
458                        len = next_output_position.column - self.output_position.column;
459                        self.column += len as usize;
460                        self.output_position = next_output_position;
461                        return Some(Chunk {
462                            text: &SPACES[0..len as usize],
463                            ..self.chunk
464                        });
465                    }
466                }
467                '\n' => {
468                    self.column = 0;
469                    self.output_position += Point::new(1, 0);
470                }
471                _ => {
472                    self.column += 1;
473                    self.output_position.column += c.len_utf8() as u32;
474                }
475            }
476        }
477
478        Some(mem::take(&mut self.chunk))
479    }
480}
481
482#[cfg(test)]
483mod tests {
484    use super::*;
485    use crate::{display_map::fold_map::FoldMap, MultiBuffer};
486    use rand::{prelude::StdRng, Rng};
487
488    #[test]
489    fn test_expand_tabs() {
490        assert_eq!(
491            TabSnapshot::expand_tabs("\t".chars(), 0, 4.try_into().unwrap()),
492            0
493        );
494        assert_eq!(
495            TabSnapshot::expand_tabs("\t".chars(), 1, 4.try_into().unwrap()),
496            4
497        );
498        assert_eq!(
499            TabSnapshot::expand_tabs("\ta".chars(), 2, 4.try_into().unwrap()),
500            5
501        );
502    }
503
504    #[gpui::test(iterations = 100)]
505    fn test_random_tabs(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
506        let tab_size = NonZeroU32::new(rng.gen_range(1..=4)).unwrap();
507        let len = rng.gen_range(0..30);
508        let buffer = if rng.gen() {
509            let text = util::RandomCharIter::new(&mut rng)
510                .take(len)
511                .collect::<String>();
512            MultiBuffer::build_simple(&text, cx)
513        } else {
514            MultiBuffer::build_random(&mut rng, cx)
515        };
516        let buffer_snapshot = buffer.read(cx).snapshot(cx);
517        log::info!("Buffer text: {:?}", buffer_snapshot.text());
518
519        let (mut fold_map, _) = FoldMap::new(buffer_snapshot.clone());
520        fold_map.randomly_mutate(&mut rng);
521        let (folds_snapshot, _) = fold_map.read(buffer_snapshot, vec![]);
522        log::info!("FoldMap text: {:?}", folds_snapshot.text());
523
524        let (_, tabs_snapshot) = TabMap::new(folds_snapshot.clone(), tab_size);
525        let text = text::Rope::from(tabs_snapshot.text().as_str());
526        log::info!(
527            "TabMap text (tab size: {}): {:?}",
528            tab_size,
529            tabs_snapshot.text(),
530        );
531
532        for _ in 0..5 {
533            let end_row = rng.gen_range(0..=text.max_point().row);
534            let end_column = rng.gen_range(0..=text.line_len(end_row));
535            let mut end = TabPoint(text.clip_point(Point::new(end_row, end_column), Bias::Right));
536            let start_row = rng.gen_range(0..=text.max_point().row);
537            let start_column = rng.gen_range(0..=text.line_len(start_row));
538            let mut start =
539                TabPoint(text.clip_point(Point::new(start_row, start_column), Bias::Left));
540            if start > end {
541                mem::swap(&mut start, &mut end);
542            }
543
544            let expected_text = text
545                .chunks_in_range(text.point_to_offset(start.0)..text.point_to_offset(end.0))
546                .collect::<String>();
547            let expected_summary = TextSummary::from(expected_text.as_str());
548            assert_eq!(
549                expected_text,
550                tabs_snapshot
551                    .chunks(start..end, false, None)
552                    .map(|c| c.text)
553                    .collect::<String>(),
554                "chunks({:?}..{:?})",
555                start,
556                end
557            );
558
559            let mut actual_summary = tabs_snapshot.text_summary_for_range(start..end);
560            if tab_size.get() > 1 && folds_snapshot.text().contains('\t') {
561                actual_summary.longest_row = expected_summary.longest_row;
562                actual_summary.longest_row_chars = expected_summary.longest_row_chars;
563            }
564            assert_eq!(actual_summary, expected_summary);
565        }
566
567        for row in 0..=text.max_point().row {
568            assert_eq!(tabs_snapshot.line_len(row), text.line_len(row));
569        }
570    }
571}