selections_collection.rs

  1use std::{
  2    cell::Ref,
  3    iter, mem,
  4    ops::{Deref, DerefMut, Range, Sub},
  5    sync::Arc,
  6};
  7
  8use collections::HashMap;
  9use gpui::{AppContext, Model, Pixels};
 10use itertools::Itertools;
 11use language::{Bias, Point, Selection, SelectionGoal, TextDimension, ToPoint};
 12use util::post_inc;
 13
 14use crate::{
 15    display_map::{DisplayMap, DisplaySnapshot, ToDisplayPoint},
 16    movement::TextLayoutDetails,
 17    Anchor, DisplayPoint, ExcerptId, MultiBuffer, MultiBufferSnapshot, SelectMode, ToOffset,
 18};
 19
 20#[derive(Debug, Clone)]
 21pub struct PendingSelection {
 22    pub selection: Selection<Anchor>,
 23    pub mode: SelectMode,
 24}
 25
 26#[derive(Debug, Clone)]
 27pub struct SelectionsCollection {
 28    display_map: Model<DisplayMap>,
 29    buffer: Model<MultiBuffer>,
 30    pub next_selection_id: usize,
 31    pub line_mode: bool,
 32    disjoint: Arc<[Selection<Anchor>]>,
 33    pending: Option<PendingSelection>,
 34}
 35
 36impl SelectionsCollection {
 37    pub fn new(display_map: Model<DisplayMap>, buffer: Model<MultiBuffer>) -> Self {
 38        Self {
 39            display_map,
 40            buffer,
 41            next_selection_id: 1,
 42            line_mode: false,
 43            disjoint: Arc::from([]),
 44            pending: Some(PendingSelection {
 45                selection: Selection {
 46                    id: 0,
 47                    start: Anchor::min(),
 48                    end: Anchor::min(),
 49                    reversed: false,
 50                    goal: SelectionGoal::None,
 51                },
 52                mode: SelectMode::Character,
 53            }),
 54        }
 55    }
 56
 57    pub fn display_map(&self, cx: &mut AppContext) -> DisplaySnapshot {
 58        self.display_map.update(cx, |map, cx| map.snapshot(cx))
 59    }
 60
 61    fn buffer<'a>(&self, cx: &'a AppContext) -> Ref<'a, MultiBufferSnapshot> {
 62        self.buffer.read(cx).read(cx)
 63    }
 64
 65    pub fn clone_state(&mut self, other: &SelectionsCollection) {
 66        self.next_selection_id = other.next_selection_id;
 67        self.line_mode = other.line_mode;
 68        self.disjoint = other.disjoint.clone();
 69        self.pending = other.pending.clone();
 70    }
 71
 72    pub fn count(&self) -> usize {
 73        let mut count = self.disjoint.len();
 74        if self.pending.is_some() {
 75            count += 1;
 76        }
 77        count
 78    }
 79
 80    /// The non-pending, non-overlapping selections. There could still be a pending
 81    /// selection that overlaps these if the mouse is being dragged, etc. Returned as
 82    /// selections over Anchors.
 83    pub fn disjoint_anchors(&self) -> Arc<[Selection<Anchor>]> {
 84        self.disjoint.clone()
 85    }
 86
 87    pub fn pending_anchor(&self) -> Option<Selection<Anchor>> {
 88        self.pending
 89            .as_ref()
 90            .map(|pending| pending.selection.clone())
 91    }
 92
 93    pub fn pending<D: TextDimension + Ord + Sub<D, Output = D>>(
 94        &self,
 95        cx: &AppContext,
 96    ) -> Option<Selection<D>> {
 97        self.pending_anchor()
 98            .as_ref()
 99            .map(|pending| pending.map(|p| p.summary::<D>(&self.buffer(cx))))
100    }
101
102    pub(crate) fn pending_mode(&self) -> Option<SelectMode> {
103        self.pending.as_ref().map(|pending| pending.mode.clone())
104    }
105
106    pub fn all<'a, D>(&self, cx: &AppContext) -> Vec<Selection<D>>
107    where
108        D: 'a + TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
109    {
110        let disjoint_anchors = &self.disjoint;
111        let mut disjoint =
112            resolve_multiple::<D, _>(disjoint_anchors.iter(), &self.buffer(cx)).peekable();
113
114        let mut pending_opt = self.pending::<D>(cx);
115
116        iter::from_fn(move || {
117            if let Some(pending) = pending_opt.as_mut() {
118                while let Some(next_selection) = disjoint.peek() {
119                    if pending.start <= next_selection.end && pending.end >= next_selection.start {
120                        let next_selection = disjoint.next().unwrap();
121                        if next_selection.start < pending.start {
122                            pending.start = next_selection.start;
123                        }
124                        if next_selection.end > pending.end {
125                            pending.end = next_selection.end;
126                        }
127                    } else if next_selection.end < pending.start {
128                        return disjoint.next();
129                    } else {
130                        break;
131                    }
132                }
133
134                pending_opt.take()
135            } else {
136                disjoint.next()
137            }
138        })
139        .collect()
140    }
141
142    /// Returns all of the selections, adjusted to take into account the selection line_mode
143    pub fn all_adjusted(&self, cx: &mut AppContext) -> Vec<Selection<Point>> {
144        let mut selections = self.all::<Point>(cx);
145        if self.line_mode {
146            let map = self.display_map(cx);
147            for selection in &mut selections {
148                let new_range = map.expand_to_line(selection.range());
149                selection.start = new_range.start;
150                selection.end = new_range.end;
151            }
152        }
153        selections
154    }
155
156    pub fn all_adjusted_display(
157        &self,
158        cx: &mut AppContext,
159    ) -> (DisplaySnapshot, Vec<Selection<DisplayPoint>>) {
160        if self.line_mode {
161            let selections = self.all::<Point>(cx);
162            let map = self.display_map(cx);
163            let result = selections
164                .into_iter()
165                .map(|mut selection| {
166                    let new_range = map.expand_to_line(selection.range());
167                    selection.start = new_range.start;
168                    selection.end = new_range.end;
169                    selection.map(|point| point.to_display_point(&map))
170                })
171                .collect();
172            (map, result)
173        } else {
174            self.all_display(cx)
175        }
176    }
177
178    pub fn disjoint_in_range<'a, D>(
179        &self,
180        range: Range<Anchor>,
181        cx: &AppContext,
182    ) -> Vec<Selection<D>>
183    where
184        D: 'a + TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
185    {
186        let buffer = self.buffer(cx);
187        let start_ix = match self
188            .disjoint
189            .binary_search_by(|probe| probe.end.cmp(&range.start, &buffer))
190        {
191            Ok(ix) | Err(ix) => ix,
192        };
193        let end_ix = match self
194            .disjoint
195            .binary_search_by(|probe| probe.start.cmp(&range.end, &buffer))
196        {
197            Ok(ix) => ix + 1,
198            Err(ix) => ix,
199        };
200        resolve_multiple(&self.disjoint[start_ix..end_ix], &buffer).collect()
201    }
202
203    pub fn all_display(
204        &self,
205        cx: &mut AppContext,
206    ) -> (DisplaySnapshot, Vec<Selection<DisplayPoint>>) {
207        let display_map = self.display_map(cx);
208        let selections = self
209            .all::<Point>(cx)
210            .into_iter()
211            .map(|selection| selection.map(|point| point.to_display_point(&display_map)))
212            .collect();
213        (display_map, selections)
214    }
215
216    pub fn newest_anchor(&self) -> &Selection<Anchor> {
217        self.pending
218            .as_ref()
219            .map(|s| &s.selection)
220            .or_else(|| self.disjoint.iter().max_by_key(|s| s.id))
221            .unwrap()
222    }
223
224    pub fn newest<D: TextDimension + Ord + Sub<D, Output = D>>(
225        &self,
226        cx: &AppContext,
227    ) -> Selection<D> {
228        resolve(self.newest_anchor(), &self.buffer(cx))
229    }
230
231    pub fn newest_display(&self, cx: &mut AppContext) -> Selection<DisplayPoint> {
232        let display_map = self.display_map(cx);
233        let selection = self
234            .newest_anchor()
235            .map(|point| point.to_display_point(&display_map));
236        selection
237    }
238
239    pub fn oldest_anchor(&self) -> &Selection<Anchor> {
240        self.disjoint
241            .iter()
242            .min_by_key(|s| s.id)
243            .or_else(|| self.pending.as_ref().map(|p| &p.selection))
244            .unwrap()
245    }
246
247    pub fn oldest<D: TextDimension + Ord + Sub<D, Output = D>>(
248        &self,
249        cx: &AppContext,
250    ) -> Selection<D> {
251        resolve(self.oldest_anchor(), &self.buffer(cx))
252    }
253
254    pub fn first_anchor(&self) -> Selection<Anchor> {
255        self.disjoint[0].clone()
256    }
257
258    pub fn first<D: TextDimension + Ord + Sub<D, Output = D>>(
259        &self,
260        cx: &AppContext,
261    ) -> Selection<D> {
262        self.all(cx).first().unwrap().clone()
263    }
264
265    pub fn last<D: TextDimension + Ord + Sub<D, Output = D>>(
266        &self,
267        cx: &AppContext,
268    ) -> Selection<D> {
269        self.all(cx).last().unwrap().clone()
270    }
271
272    #[cfg(any(test, feature = "test-support"))]
273    pub fn ranges<D: TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug>(
274        &self,
275        cx: &AppContext,
276    ) -> Vec<Range<D>> {
277        self.all::<D>(cx)
278            .iter()
279            .map(|s| {
280                if s.reversed {
281                    s.end.clone()..s.start.clone()
282                } else {
283                    s.start.clone()..s.end.clone()
284                }
285            })
286            .collect()
287    }
288
289    #[cfg(any(test, feature = "test-support"))]
290    pub fn display_ranges(&self, cx: &mut AppContext) -> Vec<Range<DisplayPoint>> {
291        let display_map = self.display_map(cx);
292        self.disjoint_anchors()
293            .iter()
294            .chain(self.pending_anchor().as_ref())
295            .map(|s| {
296                if s.reversed {
297                    s.end.to_display_point(&display_map)..s.start.to_display_point(&display_map)
298                } else {
299                    s.start.to_display_point(&display_map)..s.end.to_display_point(&display_map)
300                }
301            })
302            .collect()
303    }
304
305    pub fn build_columnar_selection(
306        &mut self,
307        display_map: &DisplaySnapshot,
308        row: u32,
309        positions: &Range<Pixels>,
310        reversed: bool,
311        text_layout_details: &TextLayoutDetails,
312    ) -> Option<Selection<Point>> {
313        let is_empty = positions.start == positions.end;
314        let line_len = display_map.line_len(row);
315
316        let line = display_map.layout_row(row, &text_layout_details);
317
318        let start_col = line.closest_index_for_x(positions.start) as u32;
319        if start_col < line_len || (is_empty && positions.start == line.width) {
320            let start = DisplayPoint::new(row, start_col);
321            let end_col = line.closest_index_for_x(positions.end) as u32;
322            let end = DisplayPoint::new(row, end_col);
323
324            Some(Selection {
325                id: post_inc(&mut self.next_selection_id),
326                start: start.to_point(display_map),
327                end: end.to_point(display_map),
328                reversed,
329                goal: SelectionGoal::HorizontalRange {
330                    start: positions.start.into(),
331                    end: positions.end.into(),
332                },
333            })
334        } else {
335            None
336        }
337    }
338
339    pub(crate) fn change_with<R>(
340        &mut self,
341        cx: &mut AppContext,
342        change: impl FnOnce(&mut MutableSelectionsCollection) -> R,
343    ) -> (bool, R) {
344        let mut mutable_collection = MutableSelectionsCollection {
345            collection: self,
346            selections_changed: false,
347            cx,
348        };
349
350        let result = change(&mut mutable_collection);
351        assert!(
352            !mutable_collection.disjoint.is_empty() || mutable_collection.pending.is_some(),
353            "There must be at least one selection"
354        );
355        (mutable_collection.selections_changed, result)
356    }
357}
358
359pub struct MutableSelectionsCollection<'a> {
360    collection: &'a mut SelectionsCollection,
361    selections_changed: bool,
362    cx: &'a mut AppContext,
363}
364
365impl<'a> MutableSelectionsCollection<'a> {
366    pub fn display_map(&mut self) -> DisplaySnapshot {
367        self.collection.display_map(self.cx)
368    }
369
370    fn buffer(&self) -> Ref<MultiBufferSnapshot> {
371        self.collection.buffer(self.cx)
372    }
373
374    pub fn clear_disjoint(&mut self) {
375        self.collection.disjoint = Arc::from([]);
376    }
377
378    pub fn delete(&mut self, selection_id: usize) {
379        let mut changed = false;
380        self.collection.disjoint = self
381            .disjoint
382            .iter()
383            .filter(|selection| {
384                let found = selection.id == selection_id;
385                changed |= found;
386                !found
387            })
388            .cloned()
389            .collect();
390
391        self.selections_changed |= changed;
392    }
393
394    pub fn clear_pending(&mut self) {
395        if self.collection.pending.is_some() {
396            self.collection.pending = None;
397            self.selections_changed = true;
398        }
399    }
400
401    pub(crate) fn set_pending_anchor_range(&mut self, range: Range<Anchor>, mode: SelectMode) {
402        self.collection.pending = Some(PendingSelection {
403            selection: Selection {
404                id: post_inc(&mut self.collection.next_selection_id),
405                start: range.start,
406                end: range.end,
407                reversed: false,
408                goal: SelectionGoal::None,
409            },
410            mode,
411        });
412        self.selections_changed = true;
413    }
414
415    pub(crate) fn set_pending_display_range(
416        &mut self,
417        range: Range<DisplayPoint>,
418        mode: SelectMode,
419    ) {
420        let (start, end, reversed) = {
421            let display_map = self.display_map();
422            let buffer = self.buffer();
423            let mut start = range.start;
424            let mut end = range.end;
425            let reversed = if start > end {
426                mem::swap(&mut start, &mut end);
427                true
428            } else {
429                false
430            };
431
432            let end_bias = if end > start { Bias::Left } else { Bias::Right };
433            (
434                buffer.anchor_before(start.to_point(&display_map)),
435                buffer.anchor_at(end.to_point(&display_map), end_bias),
436                reversed,
437            )
438        };
439
440        let new_pending = PendingSelection {
441            selection: Selection {
442                id: post_inc(&mut self.collection.next_selection_id),
443                start,
444                end,
445                reversed,
446                goal: SelectionGoal::None,
447            },
448            mode,
449        };
450
451        self.collection.pending = Some(new_pending);
452        self.selections_changed = true;
453    }
454
455    pub(crate) fn set_pending(&mut self, selection: Selection<Anchor>, mode: SelectMode) {
456        self.collection.pending = Some(PendingSelection { selection, mode });
457        self.selections_changed = true;
458    }
459
460    pub fn try_cancel(&mut self) -> bool {
461        if let Some(pending) = self.collection.pending.take() {
462            if self.disjoint.is_empty() {
463                self.collection.disjoint = Arc::from([pending.selection]);
464            }
465            self.selections_changed = true;
466            return true;
467        }
468
469        let mut oldest = self.oldest_anchor().clone();
470        if self.count() > 1 {
471            self.collection.disjoint = Arc::from([oldest]);
472            self.selections_changed = true;
473            return true;
474        }
475
476        if !oldest.start.cmp(&oldest.end, &self.buffer()).is_eq() {
477            let head = oldest.head();
478            oldest.start = head.clone();
479            oldest.end = head;
480            self.collection.disjoint = Arc::from([oldest]);
481            self.selections_changed = true;
482            return true;
483        }
484
485        false
486    }
487
488    pub fn insert_range<T>(&mut self, range: Range<T>)
489    where
490        T: 'a + ToOffset + ToPoint + TextDimension + Ord + Sub<T, Output = T> + std::marker::Copy,
491    {
492        let mut selections = self.all(self.cx);
493        let mut start = range.start.to_offset(&self.buffer());
494        let mut end = range.end.to_offset(&self.buffer());
495        let reversed = if start > end {
496            mem::swap(&mut start, &mut end);
497            true
498        } else {
499            false
500        };
501        selections.push(Selection {
502            id: post_inc(&mut self.collection.next_selection_id),
503            start,
504            end,
505            reversed,
506            goal: SelectionGoal::None,
507        });
508        self.select(selections);
509    }
510
511    pub fn select<T>(&mut self, mut selections: Vec<Selection<T>>)
512    where
513        T: ToOffset + ToPoint + Ord + std::marker::Copy + std::fmt::Debug,
514    {
515        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
516        selections.sort_unstable_by_key(|s| s.start);
517        // Merge overlapping selections.
518        let mut i = 1;
519        while i < selections.len() {
520            if selections[i - 1].end >= selections[i].start {
521                let removed = selections.remove(i);
522                if removed.start < selections[i - 1].start {
523                    selections[i - 1].start = removed.start;
524                }
525                if removed.end > selections[i - 1].end {
526                    selections[i - 1].end = removed.end;
527                }
528            } else {
529                i += 1;
530            }
531        }
532
533        self.collection.disjoint = Arc::from_iter(selections.into_iter().map(|selection| {
534            let end_bias = if selection.end > selection.start {
535                Bias::Left
536            } else {
537                Bias::Right
538            };
539            Selection {
540                id: selection.id,
541                start: buffer.anchor_after(selection.start),
542                end: buffer.anchor_at(selection.end, end_bias),
543                reversed: selection.reversed,
544                goal: selection.goal,
545            }
546        }));
547
548        self.collection.pending = None;
549        self.selections_changed = true;
550    }
551
552    pub fn select_anchors(&mut self, selections: Vec<Selection<Anchor>>) {
553        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
554        let resolved_selections =
555            resolve_multiple::<usize, _>(&selections, &buffer).collect::<Vec<_>>();
556        self.select(resolved_selections);
557    }
558
559    pub fn select_ranges<I, T>(&mut self, ranges: I)
560    where
561        I: IntoIterator<Item = Range<T>>,
562        T: ToOffset,
563    {
564        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
565        let ranges = ranges
566            .into_iter()
567            .map(|range| range.start.to_offset(&buffer)..range.end.to_offset(&buffer));
568        self.select_offset_ranges(ranges);
569    }
570
571    fn select_offset_ranges<I>(&mut self, ranges: I)
572    where
573        I: IntoIterator<Item = Range<usize>>,
574    {
575        let selections = ranges
576            .into_iter()
577            .map(|range| {
578                let mut start = range.start;
579                let mut end = range.end;
580                let reversed = if start > end {
581                    mem::swap(&mut start, &mut end);
582                    true
583                } else {
584                    false
585                };
586                Selection {
587                    id: post_inc(&mut self.collection.next_selection_id),
588                    start,
589                    end,
590                    reversed,
591                    goal: SelectionGoal::None,
592                }
593            })
594            .collect::<Vec<_>>();
595
596        self.select(selections)
597    }
598
599    pub fn select_anchor_ranges<I>(&mut self, ranges: I)
600    where
601        I: IntoIterator<Item = Range<Anchor>>,
602    {
603        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
604        let selections = ranges
605            .into_iter()
606            .map(|range| {
607                let mut start = range.start;
608                let mut end = range.end;
609                let reversed = if start.cmp(&end, &buffer).is_gt() {
610                    mem::swap(&mut start, &mut end);
611                    true
612                } else {
613                    false
614                };
615                Selection {
616                    id: post_inc(&mut self.collection.next_selection_id),
617                    start,
618                    end,
619                    reversed,
620                    goal: SelectionGoal::None,
621                }
622            })
623            .collect::<Vec<_>>();
624        self.select_anchors(selections)
625    }
626
627    pub fn new_selection_id(&mut self) -> usize {
628        post_inc(&mut self.next_selection_id)
629    }
630
631    pub fn select_display_ranges<T>(&mut self, ranges: T)
632    where
633        T: IntoIterator<Item = Range<DisplayPoint>>,
634    {
635        let display_map = self.display_map();
636        let selections = ranges
637            .into_iter()
638            .map(|range| {
639                let mut start = range.start;
640                let mut end = range.end;
641                let reversed = if start > end {
642                    mem::swap(&mut start, &mut end);
643                    true
644                } else {
645                    false
646                };
647                Selection {
648                    id: post_inc(&mut self.collection.next_selection_id),
649                    start: start.to_point(&display_map),
650                    end: end.to_point(&display_map),
651                    reversed,
652                    goal: SelectionGoal::None,
653                }
654            })
655            .collect();
656        self.select(selections);
657    }
658
659    pub fn move_with(
660        &mut self,
661        mut move_selection: impl FnMut(&DisplaySnapshot, &mut Selection<DisplayPoint>),
662    ) {
663        let mut changed = false;
664        let display_map = self.display_map();
665        let selections = self
666            .all::<Point>(self.cx)
667            .into_iter()
668            .map(|selection| {
669                let mut moved_selection =
670                    selection.map(|point| point.to_display_point(&display_map));
671                move_selection(&display_map, &mut moved_selection);
672                let moved_selection =
673                    moved_selection.map(|display_point| display_point.to_point(&display_map));
674                if selection != moved_selection {
675                    changed = true;
676                }
677                moved_selection
678            })
679            .collect();
680
681        if changed {
682            self.select(selections)
683        }
684    }
685
686    pub fn move_offsets_with(
687        &mut self,
688        mut move_selection: impl FnMut(&MultiBufferSnapshot, &mut Selection<usize>),
689    ) {
690        let mut changed = false;
691        let snapshot = self.buffer().clone();
692        let selections = self
693            .all::<usize>(self.cx)
694            .into_iter()
695            .map(|selection| {
696                let mut moved_selection = selection.clone();
697                move_selection(&snapshot, &mut moved_selection);
698                if selection != moved_selection {
699                    changed = true;
700                }
701                moved_selection
702            })
703            .collect();
704        drop(snapshot);
705
706        if changed {
707            self.select(selections)
708        }
709    }
710
711    pub fn move_heads_with(
712        &mut self,
713        mut update_head: impl FnMut(
714            &DisplaySnapshot,
715            DisplayPoint,
716            SelectionGoal,
717        ) -> (DisplayPoint, SelectionGoal),
718    ) {
719        self.move_with(|map, selection| {
720            let (new_head, new_goal) = update_head(map, selection.head(), selection.goal);
721            selection.set_head(new_head, new_goal);
722        });
723    }
724
725    pub fn move_cursors_with(
726        &mut self,
727        mut update_cursor_position: impl FnMut(
728            &DisplaySnapshot,
729            DisplayPoint,
730            SelectionGoal,
731        ) -> (DisplayPoint, SelectionGoal),
732    ) {
733        self.move_with(|map, selection| {
734            let (cursor, new_goal) = update_cursor_position(map, selection.head(), selection.goal);
735            selection.collapse_to(cursor, new_goal)
736        });
737    }
738
739    pub fn maybe_move_cursors_with(
740        &mut self,
741        mut update_cursor_position: impl FnMut(
742            &DisplaySnapshot,
743            DisplayPoint,
744            SelectionGoal,
745        ) -> Option<(DisplayPoint, SelectionGoal)>,
746    ) {
747        self.move_cursors_with(|map, point, goal| {
748            update_cursor_position(map, point, goal).unwrap_or((point, goal))
749        })
750    }
751
752    pub fn replace_cursors_with(
753        &mut self,
754        mut find_replacement_cursors: impl FnMut(&DisplaySnapshot) -> Vec<DisplayPoint>,
755    ) {
756        let display_map = self.display_map();
757        let new_selections = find_replacement_cursors(&display_map)
758            .into_iter()
759            .map(|cursor| {
760                let cursor_point = cursor.to_point(&display_map);
761                Selection {
762                    id: post_inc(&mut self.collection.next_selection_id),
763                    start: cursor_point,
764                    end: cursor_point,
765                    reversed: false,
766                    goal: SelectionGoal::None,
767                }
768            })
769            .collect();
770        self.select(new_selections);
771    }
772
773    /// Compute new ranges for any selections that were located in excerpts that have
774    /// since been removed.
775    ///
776    /// Returns a `HashMap` indicating which selections whose former head position
777    /// was no longer present. The keys of the map are selection ids. The values are
778    /// the id of the new excerpt where the head of the selection has been moved.
779    pub fn refresh(&mut self) -> HashMap<usize, ExcerptId> {
780        let mut pending = self.collection.pending.take();
781        let mut selections_with_lost_position = HashMap::default();
782
783        let anchors_with_status = {
784            let buffer = self.buffer();
785            let disjoint_anchors = self
786                .disjoint
787                .iter()
788                .flat_map(|selection| [&selection.start, &selection.end]);
789            buffer.refresh_anchors(disjoint_anchors)
790        };
791        let adjusted_disjoint: Vec<_> = anchors_with_status
792            .chunks(2)
793            .map(|selection_anchors| {
794                let (anchor_ix, start, kept_start) = selection_anchors[0].clone();
795                let (_, end, kept_end) = selection_anchors[1].clone();
796                let selection = &self.disjoint[anchor_ix / 2];
797                let kept_head = if selection.reversed {
798                    kept_start
799                } else {
800                    kept_end
801                };
802                if !kept_head {
803                    selections_with_lost_position.insert(selection.id, selection.head().excerpt_id);
804                }
805
806                Selection {
807                    id: selection.id,
808                    start,
809                    end,
810                    reversed: selection.reversed,
811                    goal: selection.goal,
812                }
813            })
814            .collect();
815
816        if !adjusted_disjoint.is_empty() {
817            let resolved_selections =
818                resolve_multiple(adjusted_disjoint.iter(), &self.buffer()).collect();
819            self.select::<usize>(resolved_selections);
820        }
821
822        if let Some(pending) = pending.as_mut() {
823            let buffer = self.buffer();
824            let anchors =
825                buffer.refresh_anchors([&pending.selection.start, &pending.selection.end]);
826            let (_, start, kept_start) = anchors[0].clone();
827            let (_, end, kept_end) = anchors[1].clone();
828            let kept_head = if pending.selection.reversed {
829                kept_start
830            } else {
831                kept_end
832            };
833            if !kept_head {
834                selections_with_lost_position
835                    .insert(pending.selection.id, pending.selection.head().excerpt_id);
836            }
837
838            pending.selection.start = start;
839            pending.selection.end = end;
840        }
841        self.collection.pending = pending;
842        self.selections_changed = true;
843
844        selections_with_lost_position
845    }
846}
847
848impl<'a> Deref for MutableSelectionsCollection<'a> {
849    type Target = SelectionsCollection;
850    fn deref(&self) -> &Self::Target {
851        self.collection
852    }
853}
854
855impl<'a> DerefMut for MutableSelectionsCollection<'a> {
856    fn deref_mut(&mut self) -> &mut Self::Target {
857        self.collection
858    }
859}
860
861// Panics if passed selections are not in order
862pub(crate) fn resolve_multiple<'a, D, I>(
863    selections: I,
864    snapshot: &MultiBufferSnapshot,
865) -> impl 'a + Iterator<Item = Selection<D>>
866where
867    D: TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
868    I: 'a + IntoIterator<Item = &'a Selection<Anchor>>,
869{
870    let (to_summarize, selections) = selections.into_iter().tee();
871    let mut summaries = snapshot
872        .summaries_for_anchors::<D, _>(
873            to_summarize
874                .flat_map(|s| [&s.start, &s.end])
875                .collect::<Vec<_>>(),
876        )
877        .into_iter();
878    selections.map(move |s| Selection {
879        id: s.id,
880        start: summaries.next().unwrap(),
881        end: summaries.next().unwrap(),
882        reversed: s.reversed,
883        goal: s.goal,
884    })
885}
886
887fn resolve<D: TextDimension + Ord + Sub<D, Output = D>>(
888    selection: &Selection<Anchor>,
889    buffer: &MultiBufferSnapshot,
890) -> Selection<D> {
891    selection.map(|p| p.summary::<D>(buffer))
892}