buffer.rs

  1use crate::*;
  2use clock::ReplicaId;
  3use rand::prelude::*;
  4use std::{
  5    cell::RefCell,
  6    cmp::Ordering,
  7    env,
  8    iter::Iterator,
  9    rc::Rc,
 10    time::{Duration, Instant},
 11};
 12
 13#[test]
 14fn test_edit() {
 15    let mut buffer = TextBuffer::new(0, 0, History::new("abc".into()));
 16    assert_eq!(buffer.text(), "abc");
 17    buffer.edit(vec![3..3], "def");
 18    assert_eq!(buffer.text(), "abcdef");
 19    buffer.edit(vec![0..0], "ghi");
 20    assert_eq!(buffer.text(), "ghiabcdef");
 21    buffer.edit(vec![5..5], "jkl");
 22    assert_eq!(buffer.text(), "ghiabjklcdef");
 23    buffer.edit(vec![6..7], "");
 24    assert_eq!(buffer.text(), "ghiabjlcdef");
 25    buffer.edit(vec![4..9], "mno");
 26    assert_eq!(buffer.text(), "ghiamnoef");
 27}
 28
 29#[gpui::test]
 30fn test_edit_events(cx: &mut gpui::MutableAppContext) {
 31    let mut now = Instant::now();
 32    let buffer_1_events = Rc::new(RefCell::new(Vec::new()));
 33    let buffer_2_events = Rc::new(RefCell::new(Vec::new()));
 34
 35    let buffer1 = cx.add_model(|cx| Buffer::new(0, "abcdef", cx));
 36    let buffer2 = cx.add_model(|cx| Buffer::new(1, "abcdef", cx));
 37    let buffer_ops = buffer1.update(cx, |buffer, cx| {
 38        let buffer_1_events = buffer_1_events.clone();
 39        cx.subscribe(&buffer1, move |_, _, event, _| {
 40            buffer_1_events.borrow_mut().push(event.clone())
 41        })
 42        .detach();
 43        let buffer_2_events = buffer_2_events.clone();
 44        cx.subscribe(&buffer2, move |_, _, event, _| {
 45            buffer_2_events.borrow_mut().push(event.clone())
 46        })
 47        .detach();
 48
 49        // An edit emits an edited event, followed by a dirtied event,
 50        // since the buffer was previously in a clean state.
 51        buffer.edit(Some(2..4), "XYZ", cx);
 52
 53        // An empty transaction does not emit any events.
 54        buffer.start_transaction(None).unwrap();
 55        buffer.end_transaction(None, cx).unwrap();
 56
 57        // A transaction containing two edits emits one edited event.
 58        now += Duration::from_secs(1);
 59        buffer.start_transaction_at(None, now).unwrap();
 60        buffer.edit(Some(5..5), "u", cx);
 61        buffer.edit(Some(6..6), "w", cx);
 62        buffer.end_transaction_at(None, now, cx).unwrap();
 63
 64        // Undoing a transaction emits one edited event.
 65        buffer.undo(cx);
 66
 67        buffer.operations.clone()
 68    });
 69
 70    // Incorporating a set of remote ops emits a single edited event,
 71    // followed by a dirtied event.
 72    buffer2.update(cx, |buffer, cx| {
 73        buffer.apply_ops(buffer_ops, cx).unwrap();
 74    });
 75
 76    let buffer_1_events = buffer_1_events.borrow();
 77    assert_eq!(
 78        *buffer_1_events,
 79        vec![Event::Edited, Event::Dirtied, Event::Edited, Event::Edited]
 80    );
 81
 82    let buffer_2_events = buffer_2_events.borrow();
 83    assert_eq!(*buffer_2_events, vec![Event::Edited, Event::Dirtied]);
 84}
 85
 86#[gpui::test(iterations = 100)]
 87fn test_random_edits(mut rng: StdRng) {
 88    let operations = env::var("OPERATIONS")
 89        .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
 90        .unwrap_or(10);
 91
 92    let reference_string_len = rng.gen_range(0..3);
 93    let mut reference_string = RandomCharIter::new(&mut rng)
 94        .take(reference_string_len)
 95        .collect::<String>();
 96    let mut buffer = TextBuffer::new(0, 0, History::new(reference_string.clone().into()));
 97    buffer.history.group_interval = Duration::from_millis(rng.gen_range(0..=200));
 98    let mut buffer_versions = Vec::new();
 99    log::info!(
100        "buffer text {:?}, version: {:?}",
101        buffer.text(),
102        buffer.version()
103    );
104
105    for _i in 0..operations {
106        let (old_ranges, new_text, _) = buffer.randomly_edit(&mut rng, 5);
107        for old_range in old_ranges.iter().rev() {
108            reference_string.replace_range(old_range.clone(), &new_text);
109        }
110        assert_eq!(buffer.text(), reference_string);
111        log::info!(
112            "buffer text {:?}, version: {:?}",
113            buffer.text(),
114            buffer.version()
115        );
116
117        if rng.gen_bool(0.25) {
118            buffer.randomly_undo_redo(&mut rng);
119            reference_string = buffer.text();
120            log::info!(
121                "buffer text {:?}, version: {:?}",
122                buffer.text(),
123                buffer.version()
124            );
125        }
126
127        let range = buffer.random_byte_range(0, &mut rng);
128        assert_eq!(
129            buffer.text_summary_for_range(range.clone()),
130            TextSummary::from(&reference_string[range])
131        );
132
133        if rng.gen_bool(0.3) {
134            buffer_versions.push(buffer.clone());
135        }
136    }
137
138    for mut old_buffer in buffer_versions {
139        let edits = buffer
140            .edits_since(old_buffer.version.clone())
141            .collect::<Vec<_>>();
142
143        log::info!(
144            "mutating old buffer version {:?}, text: {:?}, edits since: {:?}",
145            old_buffer.version(),
146            old_buffer.text(),
147            edits,
148        );
149
150        let mut delta = 0_isize;
151        for edit in edits {
152            let old_start = (edit.old_bytes.start as isize + delta) as usize;
153            let new_text: String = buffer.text_for_range(edit.new_bytes.clone()).collect();
154            old_buffer.edit(Some(old_start..old_start + edit.deleted_bytes()), new_text);
155            delta += edit.delta();
156        }
157        assert_eq!(old_buffer.text(), buffer.text());
158    }
159}
160
161#[test]
162fn test_line_len() {
163    let mut buffer = TextBuffer::new(0, 0, History::new("".into()));
164    buffer.edit(vec![0..0], "abcd\nefg\nhij");
165    buffer.edit(vec![12..12], "kl\nmno");
166    buffer.edit(vec![18..18], "\npqrs\n");
167    buffer.edit(vec![18..21], "\nPQ");
168
169    assert_eq!(buffer.line_len(0), 4);
170    assert_eq!(buffer.line_len(1), 3);
171    assert_eq!(buffer.line_len(2), 5);
172    assert_eq!(buffer.line_len(3), 3);
173    assert_eq!(buffer.line_len(4), 4);
174    assert_eq!(buffer.line_len(5), 0);
175}
176
177#[test]
178fn test_text_summary_for_range() {
179    let buffer = TextBuffer::new(0, 0, History::new("ab\nefg\nhklm\nnopqrs\ntuvwxyz".into()));
180    assert_eq!(
181        buffer.text_summary_for_range(1..3),
182        TextSummary {
183            bytes: 2,
184            lines: Point::new(1, 0),
185            first_line_chars: 1,
186            last_line_chars: 0,
187            longest_row: 0,
188            longest_row_chars: 1,
189        }
190    );
191    assert_eq!(
192        buffer.text_summary_for_range(1..12),
193        TextSummary {
194            bytes: 11,
195            lines: Point::new(3, 0),
196            first_line_chars: 1,
197            last_line_chars: 0,
198            longest_row: 2,
199            longest_row_chars: 4,
200        }
201    );
202    assert_eq!(
203        buffer.text_summary_for_range(0..20),
204        TextSummary {
205            bytes: 20,
206            lines: Point::new(4, 1),
207            first_line_chars: 2,
208            last_line_chars: 1,
209            longest_row: 3,
210            longest_row_chars: 6,
211        }
212    );
213    assert_eq!(
214        buffer.text_summary_for_range(0..22),
215        TextSummary {
216            bytes: 22,
217            lines: Point::new(4, 3),
218            first_line_chars: 2,
219            last_line_chars: 3,
220            longest_row: 3,
221            longest_row_chars: 6,
222        }
223    );
224    assert_eq!(
225        buffer.text_summary_for_range(7..22),
226        TextSummary {
227            bytes: 15,
228            lines: Point::new(2, 3),
229            first_line_chars: 4,
230            last_line_chars: 3,
231            longest_row: 1,
232            longest_row_chars: 6,
233        }
234    );
235}
236
237#[test]
238fn test_chars_at() {
239    let mut buffer = TextBuffer::new(0, 0, History::new("".into()));
240    buffer.edit(vec![0..0], "abcd\nefgh\nij");
241    buffer.edit(vec![12..12], "kl\nmno");
242    buffer.edit(vec![18..18], "\npqrs");
243    buffer.edit(vec![18..21], "\nPQ");
244
245    let chars = buffer.chars_at(Point::new(0, 0));
246    assert_eq!(chars.collect::<String>(), "abcd\nefgh\nijkl\nmno\nPQrs");
247
248    let chars = buffer.chars_at(Point::new(1, 0));
249    assert_eq!(chars.collect::<String>(), "efgh\nijkl\nmno\nPQrs");
250
251    let chars = buffer.chars_at(Point::new(2, 0));
252    assert_eq!(chars.collect::<String>(), "ijkl\nmno\nPQrs");
253
254    let chars = buffer.chars_at(Point::new(3, 0));
255    assert_eq!(chars.collect::<String>(), "mno\nPQrs");
256
257    let chars = buffer.chars_at(Point::new(4, 0));
258    assert_eq!(chars.collect::<String>(), "PQrs");
259
260    // Regression test:
261    let mut buffer = TextBuffer::new(0, 0, History::new("".into()));
262    buffer.edit(vec![0..0], "[workspace]\nmembers = [\n    \"xray_core\",\n    \"xray_server\",\n    \"xray_cli\",\n    \"xray_wasm\",\n]\n");
263    buffer.edit(vec![60..60], "\n");
264
265    let chars = buffer.chars_at(Point::new(6, 0));
266    assert_eq!(chars.collect::<String>(), "    \"xray_wasm\",\n]\n");
267}
268
269#[test]
270fn test_anchors() {
271    let mut buffer = TextBuffer::new(0, 0, History::new("".into()));
272    buffer.edit(vec![0..0], "abc");
273    let left_anchor = buffer.anchor_before(2);
274    let right_anchor = buffer.anchor_after(2);
275
276    buffer.edit(vec![1..1], "def\n");
277    assert_eq!(buffer.text(), "adef\nbc");
278    assert_eq!(left_anchor.to_offset(&buffer), 6);
279    assert_eq!(right_anchor.to_offset(&buffer), 6);
280    assert_eq!(left_anchor.to_point(&buffer), Point { row: 1, column: 1 });
281    assert_eq!(right_anchor.to_point(&buffer), Point { row: 1, column: 1 });
282
283    buffer.edit(vec![2..3], "");
284    assert_eq!(buffer.text(), "adf\nbc");
285    assert_eq!(left_anchor.to_offset(&buffer), 5);
286    assert_eq!(right_anchor.to_offset(&buffer), 5);
287    assert_eq!(left_anchor.to_point(&buffer), Point { row: 1, column: 1 });
288    assert_eq!(right_anchor.to_point(&buffer), Point { row: 1, column: 1 });
289
290    buffer.edit(vec![5..5], "ghi\n");
291    assert_eq!(buffer.text(), "adf\nbghi\nc");
292    assert_eq!(left_anchor.to_offset(&buffer), 5);
293    assert_eq!(right_anchor.to_offset(&buffer), 9);
294    assert_eq!(left_anchor.to_point(&buffer), Point { row: 1, column: 1 });
295    assert_eq!(right_anchor.to_point(&buffer), Point { row: 2, column: 0 });
296
297    buffer.edit(vec![7..9], "");
298    assert_eq!(buffer.text(), "adf\nbghc");
299    assert_eq!(left_anchor.to_offset(&buffer), 5);
300    assert_eq!(right_anchor.to_offset(&buffer), 7);
301    assert_eq!(left_anchor.to_point(&buffer), Point { row: 1, column: 1 },);
302    assert_eq!(right_anchor.to_point(&buffer), Point { row: 1, column: 3 });
303
304    // Ensure anchoring to a point is equivalent to anchoring to an offset.
305    assert_eq!(
306        buffer.anchor_before(Point { row: 0, column: 0 }),
307        buffer.anchor_before(0)
308    );
309    assert_eq!(
310        buffer.anchor_before(Point { row: 0, column: 1 }),
311        buffer.anchor_before(1)
312    );
313    assert_eq!(
314        buffer.anchor_before(Point { row: 0, column: 2 }),
315        buffer.anchor_before(2)
316    );
317    assert_eq!(
318        buffer.anchor_before(Point { row: 0, column: 3 }),
319        buffer.anchor_before(3)
320    );
321    assert_eq!(
322        buffer.anchor_before(Point { row: 1, column: 0 }),
323        buffer.anchor_before(4)
324    );
325    assert_eq!(
326        buffer.anchor_before(Point { row: 1, column: 1 }),
327        buffer.anchor_before(5)
328    );
329    assert_eq!(
330        buffer.anchor_before(Point { row: 1, column: 2 }),
331        buffer.anchor_before(6)
332    );
333    assert_eq!(
334        buffer.anchor_before(Point { row: 1, column: 3 }),
335        buffer.anchor_before(7)
336    );
337    assert_eq!(
338        buffer.anchor_before(Point { row: 1, column: 4 }),
339        buffer.anchor_before(8)
340    );
341
342    // Comparison between anchors.
343    let anchor_at_offset_0 = buffer.anchor_before(0);
344    let anchor_at_offset_1 = buffer.anchor_before(1);
345    let anchor_at_offset_2 = buffer.anchor_before(2);
346
347    assert_eq!(
348        anchor_at_offset_0
349            .cmp(&anchor_at_offset_0, &buffer)
350            .unwrap(),
351        Ordering::Equal
352    );
353    assert_eq!(
354        anchor_at_offset_1
355            .cmp(&anchor_at_offset_1, &buffer)
356            .unwrap(),
357        Ordering::Equal
358    );
359    assert_eq!(
360        anchor_at_offset_2
361            .cmp(&anchor_at_offset_2, &buffer)
362            .unwrap(),
363        Ordering::Equal
364    );
365
366    assert_eq!(
367        anchor_at_offset_0
368            .cmp(&anchor_at_offset_1, &buffer)
369            .unwrap(),
370        Ordering::Less
371    );
372    assert_eq!(
373        anchor_at_offset_1
374            .cmp(&anchor_at_offset_2, &buffer)
375            .unwrap(),
376        Ordering::Less
377    );
378    assert_eq!(
379        anchor_at_offset_0
380            .cmp(&anchor_at_offset_2, &buffer)
381            .unwrap(),
382        Ordering::Less
383    );
384
385    assert_eq!(
386        anchor_at_offset_1
387            .cmp(&anchor_at_offset_0, &buffer)
388            .unwrap(),
389        Ordering::Greater
390    );
391    assert_eq!(
392        anchor_at_offset_2
393            .cmp(&anchor_at_offset_1, &buffer)
394            .unwrap(),
395        Ordering::Greater
396    );
397    assert_eq!(
398        anchor_at_offset_2
399            .cmp(&anchor_at_offset_0, &buffer)
400            .unwrap(),
401        Ordering::Greater
402    );
403}
404
405#[test]
406fn test_anchors_at_start_and_end() {
407    let mut buffer = TextBuffer::new(0, 0, History::new("".into()));
408    let before_start_anchor = buffer.anchor_before(0);
409    let after_end_anchor = buffer.anchor_after(0);
410
411    buffer.edit(vec![0..0], "abc");
412    assert_eq!(buffer.text(), "abc");
413    assert_eq!(before_start_anchor.to_offset(&buffer), 0);
414    assert_eq!(after_end_anchor.to_offset(&buffer), 3);
415
416    let after_start_anchor = buffer.anchor_after(0);
417    let before_end_anchor = buffer.anchor_before(3);
418
419    buffer.edit(vec![3..3], "def");
420    buffer.edit(vec![0..0], "ghi");
421    assert_eq!(buffer.text(), "ghiabcdef");
422    assert_eq!(before_start_anchor.to_offset(&buffer), 0);
423    assert_eq!(after_start_anchor.to_offset(&buffer), 3);
424    assert_eq!(before_end_anchor.to_offset(&buffer), 6);
425    assert_eq!(after_end_anchor.to_offset(&buffer), 9);
426}
427
428#[gpui::test]
429async fn test_apply_diff(mut cx: gpui::TestAppContext) {
430    let text = "a\nbb\nccc\ndddd\neeeee\nffffff\n";
431    let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
432
433    let text = "a\nccc\ndddd\nffffff\n";
434    let diff = buffer.read_with(&cx, |b, cx| b.diff(text.into(), cx)).await;
435    buffer.update(&mut cx, |b, cx| b.apply_diff(diff, cx));
436    cx.read(|cx| assert_eq!(buffer.read(cx).text(), text));
437
438    let text = "a\n1\n\nccc\ndd2dd\nffffff\n";
439    let diff = buffer.read_with(&cx, |b, cx| b.diff(text.into(), cx)).await;
440    buffer.update(&mut cx, |b, cx| b.apply_diff(diff, cx));
441    cx.read(|cx| assert_eq!(buffer.read(cx).text(), text));
442}
443
444#[test]
445fn test_undo_redo() {
446    let mut buffer = TextBuffer::new(0, 0, History::new("1234".into()));
447    // Set group interval to zero so as to not group edits in the undo stack.
448    buffer.history.group_interval = Duration::from_secs(0);
449
450    buffer.edit(vec![1..1], "abx");
451    buffer.edit(vec![3..4], "yzef");
452    buffer.edit(vec![3..5], "cd");
453    assert_eq!(buffer.text(), "1abcdef234");
454
455    let transactions = buffer.history.undo_stack.clone();
456    assert_eq!(transactions.len(), 3);
457
458    buffer.undo_or_redo(transactions[0].clone()).unwrap();
459    assert_eq!(buffer.text(), "1cdef234");
460    buffer.undo_or_redo(transactions[0].clone()).unwrap();
461    assert_eq!(buffer.text(), "1abcdef234");
462
463    buffer.undo_or_redo(transactions[1].clone()).unwrap();
464    assert_eq!(buffer.text(), "1abcdx234");
465    buffer.undo_or_redo(transactions[2].clone()).unwrap();
466    assert_eq!(buffer.text(), "1abx234");
467    buffer.undo_or_redo(transactions[1].clone()).unwrap();
468    assert_eq!(buffer.text(), "1abyzef234");
469    buffer.undo_or_redo(transactions[2].clone()).unwrap();
470    assert_eq!(buffer.text(), "1abcdef234");
471
472    buffer.undo_or_redo(transactions[2].clone()).unwrap();
473    assert_eq!(buffer.text(), "1abyzef234");
474    buffer.undo_or_redo(transactions[0].clone()).unwrap();
475    assert_eq!(buffer.text(), "1yzef234");
476    buffer.undo_or_redo(transactions[1].clone()).unwrap();
477    assert_eq!(buffer.text(), "1234");
478}
479
480#[test]
481fn test_history() {
482    let mut now = Instant::now();
483    let mut buffer = TextBuffer::new(0, 0, History::new("123456".into()));
484
485    let set_id = if let Operation::UpdateSelections { set_id, .. } =
486        buffer.add_selection_set(buffer.selections_from_ranges(vec![4..4]).unwrap())
487    {
488        set_id
489    } else {
490        unreachable!()
491    };
492    buffer.start_transaction_at(Some(set_id), now).unwrap();
493    buffer.edit(vec![2..4], "cd");
494    buffer.end_transaction_at(Some(set_id), now).unwrap();
495    assert_eq!(buffer.text(), "12cd56");
496    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![4..4]);
497
498    buffer.start_transaction_at(Some(set_id), now).unwrap();
499    buffer
500        .update_selection_set(set_id, buffer.selections_from_ranges(vec![1..3]).unwrap())
501        .unwrap();
502    buffer.edit(vec![4..5], "e");
503    buffer.end_transaction_at(Some(set_id), now).unwrap();
504    assert_eq!(buffer.text(), "12cde6");
505    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![1..3]);
506
507    now += buffer.history.group_interval + Duration::from_millis(1);
508    buffer.start_transaction_at(Some(set_id), now).unwrap();
509    buffer
510        .update_selection_set(set_id, buffer.selections_from_ranges(vec![2..2]).unwrap())
511        .unwrap();
512    buffer.edit(vec![0..1], "a");
513    buffer.edit(vec![1..1], "b");
514    buffer.end_transaction_at(Some(set_id), now).unwrap();
515    assert_eq!(buffer.text(), "ab2cde6");
516    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![3..3]);
517
518    // Last transaction happened past the group interval, undo it on its
519    // own.
520    buffer.undo();
521    assert_eq!(buffer.text(), "12cde6");
522    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![1..3]);
523
524    // First two transactions happened within the group interval, undo them
525    // together.
526    buffer.undo();
527    assert_eq!(buffer.text(), "123456");
528    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![4..4]);
529
530    // Redo the first two transactions together.
531    buffer.redo();
532    assert_eq!(buffer.text(), "12cde6");
533    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![1..3]);
534
535    // Redo the last transaction on its own.
536    buffer.redo();
537    assert_eq!(buffer.text(), "ab2cde6");
538    assert_eq!(buffer.selection_ranges(set_id).unwrap(), vec![3..3]);
539
540    buffer.start_transaction_at(None, now).unwrap();
541    assert!(buffer.end_transaction_at(None, now).is_none());
542    buffer.undo();
543    assert_eq!(buffer.text(), "12cde6");
544}
545
546#[test]
547fn test_concurrent_edits() {
548    let text = "abcdef";
549
550    let mut buffer1 = TextBuffer::new(1, 0, History::new(text.into()));
551    let mut buffer2 = TextBuffer::new(2, 0, History::new(text.into()));
552    let mut buffer3 = TextBuffer::new(3, 0, History::new(text.into()));
553
554    let buf1_op = buffer1.edit(vec![1..2], "12");
555    assert_eq!(buffer1.text(), "a12cdef");
556    let buf2_op = buffer2.edit(vec![3..4], "34");
557    assert_eq!(buffer2.text(), "abc34ef");
558    let buf3_op = buffer3.edit(vec![5..6], "56");
559    assert_eq!(buffer3.text(), "abcde56");
560
561    buffer1.apply_op(Operation::Edit(buf2_op.clone())).unwrap();
562    buffer1.apply_op(Operation::Edit(buf3_op.clone())).unwrap();
563    buffer2.apply_op(Operation::Edit(buf1_op.clone())).unwrap();
564    buffer2.apply_op(Operation::Edit(buf3_op.clone())).unwrap();
565    buffer3.apply_op(Operation::Edit(buf1_op.clone())).unwrap();
566    buffer3.apply_op(Operation::Edit(buf2_op.clone())).unwrap();
567
568    assert_eq!(buffer1.text(), "a12c34e56");
569    assert_eq!(buffer2.text(), "a12c34e56");
570    assert_eq!(buffer3.text(), "a12c34e56");
571}
572
573#[gpui::test(iterations = 100)]
574fn test_random_concurrent_edits(mut rng: StdRng) {
575    let peers = env::var("PEERS")
576        .map(|i| i.parse().expect("invalid `PEERS` variable"))
577        .unwrap_or(5);
578    let operations = env::var("OPERATIONS")
579        .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
580        .unwrap_or(10);
581
582    let base_text_len = rng.gen_range(0..10);
583    let base_text = RandomCharIter::new(&mut rng)
584        .take(base_text_len)
585        .collect::<String>();
586    let mut replica_ids = Vec::new();
587    let mut buffers = Vec::new();
588    let mut network = Network::new(rng.clone());
589
590    for i in 0..peers {
591        let mut buffer = TextBuffer::new(i as ReplicaId, 0, History::new(base_text.clone().into()));
592        buffer.history.group_interval = Duration::from_millis(rng.gen_range(0..=200));
593        buffers.push(buffer);
594        replica_ids.push(i as u16);
595        network.add_peer(i as u16);
596    }
597
598    log::info!("initial text: {:?}", base_text);
599
600    let mut mutation_count = operations;
601    loop {
602        let replica_index = rng.gen_range(0..peers);
603        let replica_id = replica_ids[replica_index];
604        let buffer = &mut buffers[replica_index];
605        match rng.gen_range(0..=100) {
606            0..=50 if mutation_count != 0 => {
607                let ops = buffer.randomly_mutate(&mut rng);
608                network.broadcast(buffer.replica_id, ops);
609                log::info!("buffer {} text: {:?}", buffer.replica_id, buffer.text());
610                mutation_count -= 1;
611            }
612            51..=70 if mutation_count != 0 => {
613                let ops = buffer.randomly_undo_redo(&mut rng);
614                network.broadcast(buffer.replica_id, ops);
615                mutation_count -= 1;
616            }
617            71..=100 if network.has_unreceived(replica_id) => {
618                let ops = network.receive(replica_id);
619                if !ops.is_empty() {
620                    log::info!(
621                        "peer {} applying {} ops from the network.",
622                        replica_id,
623                        ops.len()
624                    );
625                    buffer.apply_ops(ops).unwrap();
626                }
627            }
628            _ => {}
629        }
630
631        if mutation_count == 0 && network.is_idle() {
632            break;
633        }
634    }
635
636    let first_buffer = &buffers[0];
637    for buffer in &buffers[1..] {
638        assert_eq!(
639            buffer.text(),
640            first_buffer.text(),
641            "Replica {} text != Replica 0 text",
642            buffer.replica_id
643        );
644        assert_eq!(
645            buffer.selection_sets().collect::<HashMap<_, _>>(),
646            first_buffer.selection_sets().collect::<HashMap<_, _>>()
647        );
648        assert_eq!(
649            buffer.all_selection_ranges().collect::<HashMap<_, _>>(),
650            first_buffer
651                .all_selection_ranges()
652                .collect::<HashMap<_, _>>()
653        );
654    }
655}
656
657#[derive(Clone)]
658struct Envelope<T: Clone> {
659    message: T,
660    sender: ReplicaId,
661}
662
663struct Network<T: Clone, R: rand::Rng> {
664    inboxes: std::collections::BTreeMap<ReplicaId, Vec<Envelope<T>>>,
665    all_messages: Vec<T>,
666    rng: R,
667}
668
669impl<T: Clone, R: rand::Rng> Network<T, R> {
670    fn new(rng: R) -> Self {
671        Network {
672            inboxes: Default::default(),
673            all_messages: Vec::new(),
674            rng,
675        }
676    }
677
678    fn add_peer(&mut self, id: ReplicaId) {
679        self.inboxes.insert(id, Vec::new());
680    }
681
682    fn is_idle(&self) -> bool {
683        self.inboxes.values().all(|i| i.is_empty())
684    }
685
686    fn broadcast(&mut self, sender: ReplicaId, messages: Vec<T>) {
687        for (replica, inbox) in self.inboxes.iter_mut() {
688            if *replica != sender {
689                for message in &messages {
690                    let min_index = inbox
691                        .iter()
692                        .enumerate()
693                        .rev()
694                        .find_map(|(index, envelope)| {
695                            if sender == envelope.sender {
696                                Some(index + 1)
697                            } else {
698                                None
699                            }
700                        })
701                        .unwrap_or(0);
702
703                    // Insert one or more duplicates of this message *after* the previous
704                    // message delivered by this replica.
705                    for _ in 0..self.rng.gen_range(1..4) {
706                        let insertion_index = self.rng.gen_range(min_index..inbox.len() + 1);
707                        inbox.insert(
708                            insertion_index,
709                            Envelope {
710                                message: message.clone(),
711                                sender,
712                            },
713                        );
714                    }
715                }
716            }
717        }
718        self.all_messages.extend(messages);
719    }
720
721    fn has_unreceived(&self, receiver: ReplicaId) -> bool {
722        !self.inboxes[&receiver].is_empty()
723    }
724
725    fn receive(&mut self, receiver: ReplicaId) -> Vec<T> {
726        let inbox = self.inboxes.get_mut(&receiver).unwrap();
727        let count = self.rng.gen_range(0..inbox.len() + 1);
728        inbox
729            .drain(0..count)
730            .map(|envelope| envelope.message)
731            .collect()
732    }
733}