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