aboutsummaryrefslogtreecommitdiff
path: root/src/txmempool.cpp
blob: 82eec6241ffc03e5e90dc434124643adafef04bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <txmempool.h>

#include <chain.h>
#include <coins.h>
#include <common/system.h>
#include <consensus/consensus.h>
#include <consensus/tx_verify.h>
#include <consensus/validation.h>
#include <logging.h>
#include <policy/policy.h>
#include <policy/settings.h>
#include <random.h>
#include <reverse_iterator.h>
#include <util/check.h>
#include <util/feefrac.h>
#include <util/moneystr.h>
#include <util/overflow.h>
#include <util/result.h>
#include <util/time.h>
#include <util/trace.h>
#include <util/translation.h>
#include <validationinterface.h>

#include <cmath>
#include <numeric>
#include <optional>
#include <string_view>
#include <utility>

bool TestLockPointValidity(CChain& active_chain, const LockPoints& lp)
{
    AssertLockHeld(cs_main);
    // If there are relative lock times then the maxInputBlock will be set
    // If there are no relative lock times, the LockPoints don't depend on the chain
    if (lp.maxInputBlock) {
        // Check whether active_chain is an extension of the block at which the LockPoints
        // calculation was valid.  If not LockPoints are no longer valid
        if (!active_chain.Contains(lp.maxInputBlock)) {
            return false;
        }
    }

    // LockPoints still valid
    return true;
}

void CTxMemPool::UpdateForDescendants(txiter updateIt, cacheMap& cachedDescendants,
                                      const std::set<uint256>& setExclude, std::set<uint256>& descendants_to_remove)
{
    CTxMemPoolEntry::Children stageEntries, descendants;
    stageEntries = updateIt->GetMemPoolChildrenConst();

    while (!stageEntries.empty()) {
        const CTxMemPoolEntry& descendant = *stageEntries.begin();
        descendants.insert(descendant);
        stageEntries.erase(descendant);
        const CTxMemPoolEntry::Children& children = descendant.GetMemPoolChildrenConst();
        for (const CTxMemPoolEntry& childEntry : children) {
            cacheMap::iterator cacheIt = cachedDescendants.find(mapTx.iterator_to(childEntry));
            if (cacheIt != cachedDescendants.end()) {
                // We've already calculated this one, just add the entries for this set
                // but don't traverse again.
                for (txiter cacheEntry : cacheIt->second) {
                    descendants.insert(*cacheEntry);
                }
            } else if (!descendants.count(childEntry)) {
                // Schedule for later processing
                stageEntries.insert(childEntry);
            }
        }
    }
    // descendants now contains all in-mempool descendants of updateIt.
    // Update and add to cached descendant map
    int32_t modifySize = 0;
    CAmount modifyFee = 0;
    int64_t modifyCount = 0;
    for (const CTxMemPoolEntry& descendant : descendants) {
        if (!setExclude.count(descendant.GetTx().GetHash())) {
            modifySize += descendant.GetTxSize();
            modifyFee += descendant.GetModifiedFee();
            modifyCount++;
            cachedDescendants[updateIt].insert(mapTx.iterator_to(descendant));
            // Update ancestor state for each descendant
            mapTx.modify(mapTx.iterator_to(descendant), [=](CTxMemPoolEntry& e) {
              e.UpdateAncestorState(updateIt->GetTxSize(), updateIt->GetModifiedFee(), 1, updateIt->GetSigOpCost());
            });
            // Don't directly remove the transaction here -- doing so would
            // invalidate iterators in cachedDescendants. Mark it for removal
            // by inserting into descendants_to_remove.
            if (descendant.GetCountWithAncestors() > uint64_t(m_limits.ancestor_count) || descendant.GetSizeWithAncestors() > m_limits.ancestor_size_vbytes) {
                descendants_to_remove.insert(descendant.GetTx().GetHash());
            }
        }
    }
    mapTx.modify(updateIt, [=](CTxMemPoolEntry& e) { e.UpdateDescendantState(modifySize, modifyFee, modifyCount); });
}

void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256>& vHashesToUpdate)
{
    AssertLockHeld(cs);
    // For each entry in vHashesToUpdate, store the set of in-mempool, but not
    // in-vHashesToUpdate transactions, so that we don't have to recalculate
    // descendants when we come across a previously seen entry.
    cacheMap mapMemPoolDescendantsToUpdate;

    // Use a set for lookups into vHashesToUpdate (these entries are already
    // accounted for in the state of their ancestors)
    std::set<uint256> setAlreadyIncluded(vHashesToUpdate.begin(), vHashesToUpdate.end());

    std::set<uint256> descendants_to_remove;

    // Iterate in reverse, so that whenever we are looking at a transaction
    // we are sure that all in-mempool descendants have already been processed.
    // This maximizes the benefit of the descendant cache and guarantees that
    // CTxMemPoolEntry::m_children will be updated, an assumption made in
    // UpdateForDescendants.
    for (const uint256 &hash : reverse_iterate(vHashesToUpdate)) {
        // calculate children from mapNextTx
        txiter it = mapTx.find(hash);
        if (it == mapTx.end()) {
            continue;
        }
        auto iter = mapNextTx.lower_bound(COutPoint(Txid::FromUint256(hash), 0));
        // First calculate the children, and update CTxMemPoolEntry::m_children to
        // include them, and update their CTxMemPoolEntry::m_parents to include this tx.
        // we cache the in-mempool children to avoid duplicate updates
        {
            WITH_FRESH_EPOCH(m_epoch);
            for (; iter != mapNextTx.end() && iter->first->hash == hash; ++iter) {
                const uint256 &childHash = iter->second->GetHash();
                txiter childIter = mapTx.find(childHash);
                assert(childIter != mapTx.end());
                // We can skip updating entries we've encountered before or that
                // are in the block (which are already accounted for).
                if (!visited(childIter) && !setAlreadyIncluded.count(childHash)) {
                    UpdateChild(it, childIter, true);
                    UpdateParent(childIter, it, true);
                }
            }
        } // release epoch guard for UpdateForDescendants
        UpdateForDescendants(it, mapMemPoolDescendantsToUpdate, setAlreadyIncluded, descendants_to_remove);
    }

    for (const auto& txid : descendants_to_remove) {
        // This txid may have been removed already in a prior call to removeRecursive.
        // Therefore we ensure it is not yet removed already.
        if (const std::optional<txiter> txiter = GetIter(txid)) {
            removeRecursive((*txiter)->GetTx(), MemPoolRemovalReason::SIZELIMIT);
        }
    }
}

util::Result<CTxMemPool::setEntries> CTxMemPool::CalculateAncestorsAndCheckLimits(
    int64_t entry_size,
    size_t entry_count,
    CTxMemPoolEntry::Parents& staged_ancestors,
    const Limits& limits) const
{
    int64_t totalSizeWithAncestors = entry_size;
    setEntries ancestors;

    while (!staged_ancestors.empty()) {
        const CTxMemPoolEntry& stage = staged_ancestors.begin()->get();
        txiter stageit = mapTx.iterator_to(stage);

        ancestors.insert(stageit);
        staged_ancestors.erase(stage);
        totalSizeWithAncestors += stageit->GetTxSize();

        if (stageit->GetSizeWithDescendants() + entry_size > limits.descendant_size_vbytes) {
            return util::Error{Untranslated(strprintf("exceeds descendant size limit for tx %s [limit: %u]", stageit->GetTx().GetHash().ToString(), limits.descendant_size_vbytes))};
        } else if (stageit->GetCountWithDescendants() + entry_count > static_cast<uint64_t>(limits.descendant_count)) {
            return util::Error{Untranslated(strprintf("too many descendants for tx %s [limit: %u]", stageit->GetTx().GetHash().ToString(), limits.descendant_count))};
        } else if (totalSizeWithAncestors > limits.ancestor_size_vbytes) {
            return util::Error{Untranslated(strprintf("exceeds ancestor size limit [limit: %u]", limits.ancestor_size_vbytes))};
        }

        const CTxMemPoolEntry::Parents& parents = stageit->GetMemPoolParentsConst();
        for (const CTxMemPoolEntry& parent : parents) {
            txiter parent_it = mapTx.iterator_to(parent);

            // If this is a new ancestor, add it.
            if (ancestors.count(parent_it) == 0) {
                staged_ancestors.insert(parent);
            }
            if (staged_ancestors.size() + ancestors.size() + entry_count > static_cast<uint64_t>(limits.ancestor_count)) {
                return util::Error{Untranslated(strprintf("too many unconfirmed ancestors [limit: %u]", limits.ancestor_count))};
            }
        }
    }

    return ancestors;
}

util::Result<void> CTxMemPool::CheckPackageLimits(const Package& package,
                                                  const int64_t total_vsize) const
{
    size_t pack_count = package.size();

    // Package itself is busting mempool limits; should be rejected even if no staged_ancestors exist
    if (pack_count > static_cast<uint64_t>(m_limits.ancestor_count)) {
        return util::Error{Untranslated(strprintf("package count %u exceeds ancestor count limit [limit: %u]", pack_count, m_limits.ancestor_count))};
    } else if (pack_count > static_cast<uint64_t>(m_limits.descendant_count)) {
        return util::Error{Untranslated(strprintf("package count %u exceeds descendant count limit [limit: %u]", pack_count, m_limits.descendant_count))};
    } else if (total_vsize > m_limits.ancestor_size_vbytes) {
        return util::Error{Untranslated(strprintf("package size %u exceeds ancestor size limit [limit: %u]", total_vsize, m_limits.ancestor_size_vbytes))};
    } else if (total_vsize > m_limits.descendant_size_vbytes) {
        return util::Error{Untranslated(strprintf("package size %u exceeds descendant size limit [limit: %u]", total_vsize, m_limits.descendant_size_vbytes))};
    }

    CTxMemPoolEntry::Parents staged_ancestors;
    for (const auto& tx : package) {
        for (const auto& input : tx->vin) {
            std::optional<txiter> piter = GetIter(input.prevout.hash);
            if (piter) {
                staged_ancestors.insert(**piter);
                if (staged_ancestors.size() + package.size() > static_cast<uint64_t>(m_limits.ancestor_count)) {
                    return util::Error{Untranslated(strprintf("too many unconfirmed parents [limit: %u]", m_limits.ancestor_count))};
                }
            }
        }
    }
    // When multiple transactions are passed in, the ancestors and descendants of all transactions
    // considered together must be within limits even if they are not interdependent. This may be
    // stricter than the limits for each individual transaction.
    const auto ancestors{CalculateAncestorsAndCheckLimits(total_vsize, package.size(),
                                                          staged_ancestors, m_limits)};
    // It's possible to overestimate the ancestor/descendant totals.
    if (!ancestors.has_value()) return util::Error{Untranslated("possibly " + util::ErrorString(ancestors).original)};
    return {};
}

util::Result<CTxMemPool::setEntries> CTxMemPool::CalculateMemPoolAncestors(
    const CTxMemPoolEntry &entry,
    const Limits& limits,
    bool fSearchForParents /* = true */) const
{
    CTxMemPoolEntry::Parents staged_ancestors;
    const CTransaction &tx = entry.GetTx();

    if (fSearchForParents) {
        // Get parents of this transaction that are in the mempool
        // GetMemPoolParents() is only valid for entries in the mempool, so we
        // iterate mapTx to find parents.
        for (unsigned int i = 0; i < tx.vin.size(); i++) {
            std::optional<txiter> piter = GetIter(tx.vin[i].prevout.hash);
            if (piter) {
                staged_ancestors.insert(**piter);
                if (staged_ancestors.size() + 1 > static_cast<uint64_t>(limits.ancestor_count)) {
                    return util::Error{Untranslated(strprintf("too many unconfirmed parents [limit: %u]", limits.ancestor_count))};
                }
            }
        }
    } else {
        // If we're not searching for parents, we require this to already be an
        // entry in the mempool and use the entry's cached parents.
        txiter it = mapTx.iterator_to(entry);
        staged_ancestors = it->GetMemPoolParentsConst();
    }

    return CalculateAncestorsAndCheckLimits(entry.GetTxSize(), /*entry_count=*/1, staged_ancestors,
                                            limits);
}

CTxMemPool::setEntries CTxMemPool::AssumeCalculateMemPoolAncestors(
    std::string_view calling_fn_name,
    const CTxMemPoolEntry &entry,
    const Limits& limits,
    bool fSearchForParents /* = true */) const
{
    auto result{CalculateMemPoolAncestors(entry, limits, fSearchForParents)};
    if (!Assume(result)) {
        LogPrintLevel(BCLog::MEMPOOL, BCLog::Level::Error, "%s: CalculateMemPoolAncestors failed unexpectedly, continuing with empty ancestor set (%s)\n",
                      calling_fn_name, util::ErrorString(result).original);
    }
    return std::move(result).value_or(CTxMemPool::setEntries{});
}

void CTxMemPool::UpdateAncestorsOf(bool add, txiter it, setEntries &setAncestors)
{
    const CTxMemPoolEntry::Parents& parents = it->GetMemPoolParentsConst();
    // add or remove this tx as a child of each parent
    for (const CTxMemPoolEntry& parent : parents) {
        UpdateChild(mapTx.iterator_to(parent), it, add);
    }
    const int32_t updateCount = (add ? 1 : -1);
    const int32_t updateSize{updateCount * it->GetTxSize()};
    const CAmount updateFee = updateCount * it->GetModifiedFee();
    for (txiter ancestorIt : setAncestors) {
        mapTx.modify(ancestorIt, [=](CTxMemPoolEntry& e) { e.UpdateDescendantState(updateSize, updateFee, updateCount); });
    }
}

void CTxMemPool::UpdateEntryForAncestors(txiter it, const setEntries &setAncestors)
{
    int64_t updateCount = setAncestors.size();
    int64_t updateSize = 0;
    CAmount updateFee = 0;
    int64_t updateSigOpsCost = 0;
    for (txiter ancestorIt : setAncestors) {
        updateSize += ancestorIt->GetTxSize();
        updateFee += ancestorIt->GetModifiedFee();
        updateSigOpsCost += ancestorIt->GetSigOpCost();
    }
    mapTx.modify(it, [=](CTxMemPoolEntry& e){ e.UpdateAncestorState(updateSize, updateFee, updateCount, updateSigOpsCost); });
}

void CTxMemPool::UpdateChildrenForRemoval(txiter it)
{
    const CTxMemPoolEntry::Children& children = it->GetMemPoolChildrenConst();
    for (const CTxMemPoolEntry& updateIt : children) {
        UpdateParent(mapTx.iterator_to(updateIt), it, false);
    }
}

void CTxMemPool::UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants)
{
    // For each entry, walk back all ancestors and decrement size associated with this
    // transaction
    if (updateDescendants) {
        // updateDescendants should be true whenever we're not recursively
        // removing a tx and all its descendants, eg when a transaction is
        // confirmed in a block.
        // Here we only update statistics and not data in CTxMemPool::Parents
        // and CTxMemPoolEntry::Children (which we need to preserve until we're
        // finished with all operations that need to traverse the mempool).
        for (txiter removeIt : entriesToRemove) {
            setEntries setDescendants;
            CalculateDescendants(removeIt, setDescendants);
            setDescendants.erase(removeIt); // don't update state for self
            int32_t modifySize = -removeIt->GetTxSize();
            CAmount modifyFee = -removeIt->GetModifiedFee();
            int modifySigOps = -removeIt->GetSigOpCost();
            for (txiter dit : setDescendants) {
                mapTx.modify(dit, [=](CTxMemPoolEntry& e){ e.UpdateAncestorState(modifySize, modifyFee, -1, modifySigOps); });
            }
        }
    }
    for (txiter removeIt : entriesToRemove) {
        const CTxMemPoolEntry &entry = *removeIt;
        // Since this is a tx that is already in the mempool, we can call CMPA
        // with fSearchForParents = false.  If the mempool is in a consistent
        // state, then using true or false should both be correct, though false
        // should be a bit faster.
        // However, if we happen to be in the middle of processing a reorg, then
        // the mempool can be in an inconsistent state.  In this case, the set
        // of ancestors reachable via GetMemPoolParents()/GetMemPoolChildren()
        // will be the same as the set of ancestors whose packages include this
        // transaction, because when we add a new transaction to the mempool in
        // addUnchecked(), we assume it has no children, and in the case of a
        // reorg where that assumption is false, the in-mempool children aren't
        // linked to the in-block tx's until UpdateTransactionsFromBlock() is
        // called.
        // So if we're being called during a reorg, ie before
        // UpdateTransactionsFromBlock() has been called, then
        // GetMemPoolParents()/GetMemPoolChildren() will differ from the set of
        // mempool parents we'd calculate by searching, and it's important that
        // we use the cached notion of ancestor transactions as the set of
        // things to update for removal.
        auto ancestors{AssumeCalculateMemPoolAncestors(__func__, entry, Limits::NoLimits(), /*fSearchForParents=*/false)};
        // Note that UpdateAncestorsOf severs the child links that point to
        // removeIt in the entries for the parents of removeIt.
        UpdateAncestorsOf(false, removeIt, ancestors);
    }
    // After updating all the ancestor sizes, we can now sever the link between each
    // transaction being removed and any mempool children (ie, update CTxMemPoolEntry::m_parents
    // for each direct child of a transaction being removed).
    for (txiter removeIt : entriesToRemove) {
        UpdateChildrenForRemoval(removeIt);
    }
}

void CTxMemPoolEntry::UpdateDescendantState(int32_t modifySize, CAmount modifyFee, int64_t modifyCount)
{
    nSizeWithDescendants += modifySize;
    assert(nSizeWithDescendants > 0);
    nModFeesWithDescendants = SaturatingAdd(nModFeesWithDescendants, modifyFee);
    m_count_with_descendants += modifyCount;
    assert(m_count_with_descendants > 0);
}

void CTxMemPoolEntry::UpdateAncestorState(int32_t modifySize, CAmount modifyFee, int64_t modifyCount, int64_t modifySigOps)
{
    nSizeWithAncestors += modifySize;
    assert(nSizeWithAncestors > 0);
    nModFeesWithAncestors = SaturatingAdd(nModFeesWithAncestors, modifyFee);
    m_count_with_ancestors += modifyCount;
    assert(m_count_with_ancestors > 0);
    nSigOpCostWithAncestors += modifySigOps;
    assert(int(nSigOpCostWithAncestors) >= 0);
}

CTxMemPool::CTxMemPool(const Options& opts)
    : m_check_ratio{opts.check_ratio},
      m_max_size_bytes{opts.max_size_bytes},
      m_expiry{opts.expiry},
      m_incremental_relay_feerate{opts.incremental_relay_feerate},
      m_min_relay_feerate{opts.min_relay_feerate},
      m_dust_relay_feerate{opts.dust_relay_feerate},
      m_permit_bare_multisig{opts.permit_bare_multisig},
      m_max_datacarrier_bytes{opts.max_datacarrier_bytes},
      m_require_standard{opts.require_standard},
      m_full_rbf{opts.full_rbf},
      m_persist_v1_dat{opts.persist_v1_dat},
      m_limits{opts.limits},
      m_signals{opts.signals}
{
}

bool CTxMemPool::isSpent(const COutPoint& outpoint) const
{
    LOCK(cs);
    return mapNextTx.count(outpoint);
}

unsigned int CTxMemPool::GetTransactionsUpdated() const
{
    return nTransactionsUpdated;
}

void CTxMemPool::AddTransactionsUpdated(unsigned int n)
{
    nTransactionsUpdated += n;
}

void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry, setEntries &setAncestors)
{
    // Add to memory pool without checking anything.
    // Used by AcceptToMemoryPool(), which DOES do
    // all the appropriate checks.
    indexed_transaction_set::iterator newit = mapTx.emplace(CTxMemPoolEntry::ExplicitCopy, entry).first;

    // Update transaction for any feeDelta created by PrioritiseTransaction
    CAmount delta{0};
    ApplyDelta(entry.GetTx().GetHash(), delta);
    // The following call to UpdateModifiedFee assumes no previous fee modifications
    Assume(entry.GetFee() == entry.GetModifiedFee());
    if (delta) {
        mapTx.modify(newit, [&delta](CTxMemPoolEntry& e) { e.UpdateModifiedFee(delta); });
    }

    // Update cachedInnerUsage to include contained transaction's usage.
    // (When we update the entry for in-mempool parents, memory usage will be
    // further updated.)
    cachedInnerUsage += entry.DynamicMemoryUsage();

    const CTransaction& tx = newit->GetTx();
    std::set<Txid> setParentTransactions;
    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        mapNextTx.insert(std::make_pair(&tx.vin[i].prevout, &tx));
        setParentTransactions.insert(tx.vin[i].prevout.hash);
    }
    // Don't bother worrying about child transactions of this one.
    // Normal case of a new transaction arriving is that there can't be any
    // children, because such children would be orphans.
    // An exception to that is if a transaction enters that used to be in a block.
    // In that case, our disconnect block logic will call UpdateTransactionsFromBlock
    // to clean up the mess we're leaving here.

    // Update ancestors with information about this tx
    for (const auto& pit : GetIterSet(setParentTransactions)) {
            UpdateParent(newit, pit, true);
    }
    UpdateAncestorsOf(true, newit, setAncestors);
    UpdateEntryForAncestors(newit, setAncestors);

    nTransactionsUpdated++;
    totalTxSize += entry.GetTxSize();
    m_total_fee += entry.GetFee();

    txns_randomized.emplace_back(newit->GetSharedTx());
    newit->idx_randomized = txns_randomized.size() - 1;

    TRACE3(mempool, added,
        entry.GetTx().GetHash().data(),
        entry.GetTxSize(),
        entry.GetFee()
    );
}

void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
{
    // We increment mempool sequence value no matter removal reason
    // even if not directly reported below.
    uint64_t mempool_sequence = GetAndIncrementSequence();

    if (reason != MemPoolRemovalReason::BLOCK && m_signals) {
        // Notify clients that a transaction has been removed from the mempool
        // for any reason except being included in a block. Clients interested
        // in transactions included in blocks can subscribe to the BlockConnected
        // notification.
        m_signals->TransactionRemovedFromMempool(it->GetSharedTx(), reason, mempool_sequence);
    }
    TRACE5(mempool, removed,
        it->GetTx().GetHash().data(),
        RemovalReasonToString(reason).c_str(),
        it->GetTxSize(),
        it->GetFee(),
        std::chrono::duration_cast<std::chrono::duration<std::uint64_t>>(it->GetTime()).count()
    );

    for (const CTxIn& txin : it->GetTx().vin)
        mapNextTx.erase(txin.prevout);

    RemoveUnbroadcastTx(it->GetTx().GetHash(), true /* add logging because unchecked */);

    if (txns_randomized.size() > 1) {
        // Update idx_randomized of the to-be-moved entry.
        Assert(GetEntry(txns_randomized.back()->GetHash()))->idx_randomized = it->idx_randomized;
        // Remove entry from txns_randomized by replacing it with the back and deleting the back.
        txns_randomized[it->idx_randomized] = std::move(txns_randomized.back());
        txns_randomized.pop_back();
        if (txns_randomized.size() * 2 < txns_randomized.capacity())
            txns_randomized.shrink_to_fit();
    } else
        txns_randomized.clear();

    totalTxSize -= it->GetTxSize();
    m_total_fee -= it->GetFee();
    cachedInnerUsage -= it->DynamicMemoryUsage();
    cachedInnerUsage -= memusage::DynamicUsage(it->GetMemPoolParentsConst()) + memusage::DynamicUsage(it->GetMemPoolChildrenConst());
    mapTx.erase(it);
    nTransactionsUpdated++;
}

// Calculates descendants of entry that are not already in setDescendants, and adds to
// setDescendants. Assumes entryit is already a tx in the mempool and CTxMemPoolEntry::m_children
// is correct for tx and all descendants.
// Also assumes that if an entry is in setDescendants already, then all
// in-mempool descendants of it are already in setDescendants as well, so that we
// can save time by not iterating over those entries.
void CTxMemPool::CalculateDescendants(txiter entryit, setEntries& setDescendants) const
{
    setEntries stage;
    if (setDescendants.count(entryit) == 0) {
        stage.insert(entryit);
    }
    // Traverse down the children of entry, only adding children that are not
    // accounted for in setDescendants already (because those children have either
    // already been walked, or will be walked in this iteration).
    while (!stage.empty()) {
        txiter it = *stage.begin();
        setDescendants.insert(it);
        stage.erase(it);

        const CTxMemPoolEntry::Children& children = it->GetMemPoolChildrenConst();
        for (const CTxMemPoolEntry& child : children) {
            txiter childiter = mapTx.iterator_to(child);
            if (!setDescendants.count(childiter)) {
                stage.insert(childiter);
            }
        }
    }
}

void CTxMemPool::removeRecursive(const CTransaction &origTx, MemPoolRemovalReason reason)
{
    // Remove transaction from memory pool
    AssertLockHeld(cs);
        setEntries txToRemove;
        txiter origit = mapTx.find(origTx.GetHash());
        if (origit != mapTx.end()) {
            txToRemove.insert(origit);
        } else {
            // When recursively removing but origTx isn't in the mempool
            // be sure to remove any children that are in the pool. This can
            // happen during chain re-orgs if origTx isn't re-accepted into
            // the mempool for any reason.
            for (unsigned int i = 0; i < origTx.vout.size(); i++) {
                auto it = mapNextTx.find(COutPoint(origTx.GetHash(), i));
                if (it == mapNextTx.end())
                    continue;
                txiter nextit = mapTx.find(it->second->GetHash());
                assert(nextit != mapTx.end());
                txToRemove.insert(nextit);
            }
        }
        setEntries setAllRemoves;
        for (txiter it : txToRemove) {
            CalculateDescendants(it, setAllRemoves);
        }

        RemoveStaged(setAllRemoves, false, reason);
}

void CTxMemPool::removeForReorg(CChain& chain, std::function<bool(txiter)> check_final_and_mature)
{
    // Remove transactions spending a coinbase which are now immature and no-longer-final transactions
    AssertLockHeld(cs);
    AssertLockHeld(::cs_main);

    setEntries txToRemove;
    for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
        if (check_final_and_mature(it)) txToRemove.insert(it);
    }
    setEntries setAllRemoves;
    for (txiter it : txToRemove) {
        CalculateDescendants(it, setAllRemoves);
    }
    RemoveStaged(setAllRemoves, false, MemPoolRemovalReason::REORG);
    for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
        assert(TestLockPointValidity(chain, it->GetLockPoints()));
    }
}

void CTxMemPool::removeConflicts(const CTransaction &tx)
{
    // Remove transactions which depend on inputs of tx, recursively
    AssertLockHeld(cs);
    for (const CTxIn &txin : tx.vin) {
        auto it = mapNextTx.find(txin.prevout);
        if (it != mapNextTx.end()) {
            const CTransaction &txConflict = *it->second;
            if (txConflict != tx)
            {
                ClearPrioritisation(txConflict.GetHash());
                removeRecursive(txConflict, MemPoolRemovalReason::CONFLICT);
            }
        }
    }
}

/**
 * Called when a block is connected. Removes from mempool.
 */
void CTxMemPool::removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight)
{
    AssertLockHeld(cs);
    std::vector<RemovedMempoolTransactionInfo> txs_removed_for_block;
    txs_removed_for_block.reserve(vtx.size());
    for (const auto& tx : vtx)
    {
        txiter it = mapTx.find(tx->GetHash());
        if (it != mapTx.end()) {
            setEntries stage;
            stage.insert(it);
            txs_removed_for_block.emplace_back(*it);
            RemoveStaged(stage, true, MemPoolRemovalReason::BLOCK);
        }
        removeConflicts(*tx);
        ClearPrioritisation(tx->GetHash());
    }
    if (m_signals) {
        m_signals->MempoolTransactionsRemovedForBlock(txs_removed_for_block, nBlockHeight);
    }
    lastRollingFeeUpdate = GetTime();
    blockSinceLastRollingFeeBump = true;
}

void CTxMemPool::check(const CCoinsViewCache& active_coins_tip, int64_t spendheight) const
{
    if (m_check_ratio == 0) return;

    if (GetRand(m_check_ratio) >= 1) return;

    AssertLockHeld(::cs_main);
    LOCK(cs);
    LogPrint(BCLog::MEMPOOL, "Checking mempool with %u transactions and %u inputs\n", (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());

    uint64_t checkTotal = 0;
    CAmount check_total_fee{0};
    uint64_t innerUsage = 0;
    uint64_t prev_ancestor_count{0};

    CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache*>(&active_coins_tip));

    for (const auto& it : GetSortedDepthAndScore()) {
        checkTotal += it->GetTxSize();
        check_total_fee += it->GetFee();
        innerUsage += it->DynamicMemoryUsage();
        const CTransaction& tx = it->GetTx();
        innerUsage += memusage::DynamicUsage(it->GetMemPoolParentsConst()) + memusage::DynamicUsage(it->GetMemPoolChildrenConst());
        CTxMemPoolEntry::Parents setParentCheck;
        for (const CTxIn &txin : tx.vin) {
            // Check that every mempool transaction's inputs refer to available coins, or other mempool tx's.
            indexed_transaction_set::const_iterator it2 = mapTx.find(txin.prevout.hash);
            if (it2 != mapTx.end()) {
                const CTransaction& tx2 = it2->GetTx();
                assert(tx2.vout.size() > txin.prevout.n && !tx2.vout[txin.prevout.n].IsNull());
                setParentCheck.insert(*it2);
            }
            // We are iterating through the mempool entries sorted in order by ancestor count.
            // All parents must have been checked before their children and their coins added to
            // the mempoolDuplicate coins cache.
            assert(mempoolDuplicate.HaveCoin(txin.prevout));
            // Check whether its inputs are marked in mapNextTx.
            auto it3 = mapNextTx.find(txin.prevout);
            assert(it3 != mapNextTx.end());
            assert(it3->first == &txin.prevout);
            assert(it3->second == &tx);
        }
        auto comp = [](const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) -> bool {
            return a.GetTx().GetHash() == b.GetTx().GetHash();
        };
        assert(setParentCheck.size() == it->GetMemPoolParentsConst().size());
        assert(std::equal(setParentCheck.begin(), setParentCheck.end(), it->GetMemPoolParentsConst().begin(), comp));
        // Verify ancestor state is correct.
        auto ancestors{AssumeCalculateMemPoolAncestors(__func__, *it, Limits::NoLimits())};
        uint64_t nCountCheck = ancestors.size() + 1;
        int32_t nSizeCheck = it->GetTxSize();
        CAmount nFeesCheck = it->GetModifiedFee();
        int64_t nSigOpCheck = it->GetSigOpCost();

        for (txiter ancestorIt : ancestors) {
            nSizeCheck += ancestorIt->GetTxSize();
            nFeesCheck += ancestorIt->GetModifiedFee();
            nSigOpCheck += ancestorIt->GetSigOpCost();
        }

        assert(it->GetCountWithAncestors() == nCountCheck);
        assert(it->GetSizeWithAncestors() == nSizeCheck);
        assert(it->GetSigOpCostWithAncestors() == nSigOpCheck);
        assert(it->GetModFeesWithAncestors() == nFeesCheck);
        // Sanity check: we are walking in ascending ancestor count order.
        assert(prev_ancestor_count <= it->GetCountWithAncestors());
        prev_ancestor_count = it->GetCountWithAncestors();

        // Check children against mapNextTx
        CTxMemPoolEntry::Children setChildrenCheck;
        auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetHash(), 0));
        int32_t child_sizes{0};
        for (; iter != mapNextTx.end() && iter->first->hash == it->GetTx().GetHash(); ++iter) {
            txiter childit = mapTx.find(iter->second->GetHash());
            assert(childit != mapTx.end()); // mapNextTx points to in-mempool transactions
            if (setChildrenCheck.insert(*childit).second) {
                child_sizes += childit->GetTxSize();
            }
        }
        assert(setChildrenCheck.size() == it->GetMemPoolChildrenConst().size());
        assert(std::equal(setChildrenCheck.begin(), setChildrenCheck.end(), it->GetMemPoolChildrenConst().begin(), comp));
        // Also check to make sure size is greater than sum with immediate children.
        // just a sanity check, not definitive that this calc is correct...
        assert(it->GetSizeWithDescendants() >= child_sizes + it->GetTxSize());

        TxValidationState dummy_state; // Not used. CheckTxInputs() should always pass
        CAmount txfee = 0;
        assert(!tx.IsCoinBase());
        assert(Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight, txfee));
        for (const auto& input: tx.vin) mempoolDuplicate.SpendCoin(input.prevout);
        AddCoins(mempoolDuplicate, tx, std::numeric_limits<int>::max());
    }
    for (auto it = mapNextTx.cbegin(); it != mapNextTx.cend(); it++) {
        uint256 hash = it->second->GetHash();
        indexed_transaction_set::const_iterator it2 = mapTx.find(hash);
        const CTransaction& tx = it2->GetTx();
        assert(it2 != mapTx.end());
        assert(&tx == it->second);
    }

    assert(totalTxSize == checkTotal);
    assert(m_total_fee == check_total_fee);
    assert(innerUsage == cachedInnerUsage);
}

bool CTxMemPool::CompareDepthAndScore(const uint256& hasha, const uint256& hashb, bool wtxid)
{
    /* Return `true` if hasha should be considered sooner than hashb. Namely when:
     *   a is not in the mempool, but b is
     *   both are in the mempool and a has fewer ancestors than b
     *   both are in the mempool and a has a higher score than b
     */
    LOCK(cs);
    indexed_transaction_set::const_iterator j = wtxid ? get_iter_from_wtxid(hashb) : mapTx.find(hashb);
    if (j == mapTx.end()) return false;
    indexed_transaction_set::const_iterator i = wtxid ? get_iter_from_wtxid(hasha) : mapTx.find(hasha);
    if (i == mapTx.end()) return true;
    uint64_t counta = i->GetCountWithAncestors();
    uint64_t countb = j->GetCountWithAncestors();
    if (counta == countb) {
        return CompareTxMemPoolEntryByScore()(*i, *j);
    }
    return counta < countb;
}

namespace {
class DepthAndScoreComparator
{
public:
    bool operator()(const CTxMemPool::indexed_transaction_set::const_iterator& a, const CTxMemPool::indexed_transaction_set::const_iterator& b)
    {
        uint64_t counta = a->GetCountWithAncestors();
        uint64_t countb = b->GetCountWithAncestors();
        if (counta == countb) {
            return CompareTxMemPoolEntryByScore()(*a, *b);
        }
        return counta < countb;
    }
};
} // namespace

std::vector<CTxMemPool::indexed_transaction_set::const_iterator> CTxMemPool::GetSortedDepthAndScore() const
{
    std::vector<indexed_transaction_set::const_iterator> iters;
    AssertLockHeld(cs);

    iters.reserve(mapTx.size());

    for (indexed_transaction_set::iterator mi = mapTx.begin(); mi != mapTx.end(); ++mi) {
        iters.push_back(mi);
    }
    std::sort(iters.begin(), iters.end(), DepthAndScoreComparator());
    return iters;
}

static TxMempoolInfo GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it) {
    return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), it->GetFee(), it->GetTxSize(), it->GetModifiedFee() - it->GetFee()};
}

std::vector<CTxMemPoolEntryRef> CTxMemPool::entryAll() const
{
    AssertLockHeld(cs);

    std::vector<CTxMemPoolEntryRef> ret;
    ret.reserve(mapTx.size());
    for (const auto& it : GetSortedDepthAndScore()) {
        ret.emplace_back(*it);
    }
    return ret;
}

std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
{
    LOCK(cs);
    auto iters = GetSortedDepthAndScore();

    std::vector<TxMempoolInfo> ret;
    ret.reserve(mapTx.size());
    for (auto it : iters) {
        ret.push_back(GetInfo(it));
    }

    return ret;
}

const CTxMemPoolEntry* CTxMemPool::GetEntry(const Txid& txid) const
{
    AssertLockHeld(cs);
    const auto i = mapTx.find(txid);
    return i == mapTx.end() ? nullptr : &(*i);
}

CTransactionRef CTxMemPool::get(const uint256& hash) const
{
    LOCK(cs);
    indexed_transaction_set::const_iterator i = mapTx.find(hash);
    if (i == mapTx.end())
        return nullptr;
    return i->GetSharedTx();
}

TxMempoolInfo CTxMemPool::info(const GenTxid& gtxid) const
{
    LOCK(cs);
    indexed_transaction_set::const_iterator i = (gtxid.IsWtxid() ? get_iter_from_wtxid(gtxid.GetHash()) : mapTx.find(gtxid.GetHash()));
    if (i == mapTx.end())
        return TxMempoolInfo();
    return GetInfo(i);
}

TxMempoolInfo CTxMemPool::info_for_relay(const GenTxid& gtxid, uint64_t last_sequence) const
{
    LOCK(cs);
    indexed_transaction_set::const_iterator i = (gtxid.IsWtxid() ? get_iter_from_wtxid(gtxid.GetHash()) : mapTx.find(gtxid.GetHash()));
    if (i != mapTx.end() && i->GetSequence() < last_sequence) {
        return GetInfo(i);
    } else {
        return TxMempoolInfo();
    }
}

void CTxMemPool::PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta)
{
    {
        LOCK(cs);
        CAmount &delta = mapDeltas[hash];
        delta = SaturatingAdd(delta, nFeeDelta);
        txiter it = mapTx.find(hash);
        if (it != mapTx.end()) {
            mapTx.modify(it, [&nFeeDelta](CTxMemPoolEntry& e) { e.UpdateModifiedFee(nFeeDelta); });
            // Now update all ancestors' modified fees with descendants
            auto ancestors{AssumeCalculateMemPoolAncestors(__func__, *it, Limits::NoLimits(), /*fSearchForParents=*/false)};
            for (txiter ancestorIt : ancestors) {
                mapTx.modify(ancestorIt, [=](CTxMemPoolEntry& e){ e.UpdateDescendantState(0, nFeeDelta, 0);});
            }
            // Now update all descendants' modified fees with ancestors
            setEntries setDescendants;
            CalculateDescendants(it, setDescendants);
            setDescendants.erase(it);
            for (txiter descendantIt : setDescendants) {
                mapTx.modify(descendantIt, [=](CTxMemPoolEntry& e){ e.UpdateAncestorState(0, nFeeDelta, 0, 0); });
            }
            ++nTransactionsUpdated;
        }
        if (delta == 0) {
            mapDeltas.erase(hash);
            LogPrintf("PrioritiseTransaction: %s (%sin mempool) delta cleared\n", hash.ToString(), it == mapTx.end() ? "not " : "");
        } else {
            LogPrintf("PrioritiseTransaction: %s (%sin mempool) fee += %s, new delta=%s\n",
                      hash.ToString(),
                      it == mapTx.end() ? "not " : "",
                      FormatMoney(nFeeDelta),
                      FormatMoney(delta));
        }
    }
}

void CTxMemPool::ApplyDelta(const uint256& hash, CAmount &nFeeDelta) const
{
    AssertLockHeld(cs);
    std::map<uint256, CAmount>::const_iterator pos = mapDeltas.find(hash);
    if (pos == mapDeltas.end())
        return;
    const CAmount &delta = pos->second;
    nFeeDelta += delta;
}

void CTxMemPool::ClearPrioritisation(const uint256& hash)
{
    AssertLockHeld(cs);
    mapDeltas.erase(hash);
}

std::vector<CTxMemPool::delta_info> CTxMemPool::GetPrioritisedTransactions() const
{
    AssertLockNotHeld(cs);
    LOCK(cs);
    std::vector<delta_info> result;
    result.reserve(mapDeltas.size());
    for (const auto& [txid, delta] : mapDeltas) {
        const auto iter{mapTx.find(txid)};
        const bool in_mempool{iter != mapTx.end()};
        std::optional<CAmount> modified_fee;
        if (in_mempool) modified_fee = iter->GetModifiedFee();
        result.emplace_back(delta_info{in_mempool, delta, modified_fee, txid});
    }
    return result;
}

const CTransaction* CTxMemPool::GetConflictTx(const COutPoint& prevout) const
{
    const auto it = mapNextTx.find(prevout);
    return it == mapNextTx.end() ? nullptr : it->second;
}

std::optional<CTxMemPool::txiter> CTxMemPool::GetIter(const uint256& txid) const
{
    auto it = mapTx.find(txid);
    if (it != mapTx.end()) return it;
    return std::nullopt;
}

CTxMemPool::setEntries CTxMemPool::GetIterSet(const std::set<Txid>& hashes) const
{
    CTxMemPool::setEntries ret;
    for (const auto& h : hashes) {
        const auto mi = GetIter(h);
        if (mi) ret.insert(*mi);
    }
    return ret;
}

std::vector<CTxMemPool::txiter> CTxMemPool::GetIterVec(const std::vector<uint256>& txids) const
{
    AssertLockHeld(cs);
    std::vector<txiter> ret;
    ret.reserve(txids.size());
    for (const auto& txid : txids) {
        const auto it{GetIter(txid)};
        if (!it) return {};
        ret.push_back(*it);
    }
    return ret;
}

bool CTxMemPool::HasNoInputsOf(const CTransaction &tx) const
{
    for (unsigned int i = 0; i < tx.vin.size(); i++)
        if (exists(GenTxid::Txid(tx.vin[i].prevout.hash)))
            return false;
    return true;
}

CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }

bool CCoinsViewMemPool::GetCoin(const COutPoint &outpoint, Coin &coin) const {
    // Check to see if the inputs are made available by another tx in the package.
    // These Coins would not be available in the underlying CoinsView.
    if (auto it = m_temp_added.find(outpoint); it != m_temp_added.end()) {
        coin = it->second;
        return true;
    }

    // If an entry in the mempool exists, always return that one, as it's guaranteed to never
    // conflict with the underlying cache, and it cannot have pruned entries (as it contains full)
    // transactions. First checking the underlying cache risks returning a pruned entry instead.
    CTransactionRef ptx = mempool.get(outpoint.hash);
    if (ptx) {
        if (outpoint.n < ptx->vout.size()) {
            coin = Coin(ptx->vout[outpoint.n], MEMPOOL_HEIGHT, false);
            m_non_base_coins.emplace(outpoint);
            return true;
        } else {
            return false;
        }
    }
    return base->GetCoin(outpoint, coin);
}

void CCoinsViewMemPool::PackageAddTransaction(const CTransactionRef& tx)
{
    for (unsigned int n = 0; n < tx->vout.size(); ++n) {
        m_temp_added.emplace(COutPoint(tx->GetHash(), n), Coin(tx->vout[n], MEMPOOL_HEIGHT, false));
        m_non_base_coins.emplace(tx->GetHash(), n);
    }
}
void CCoinsViewMemPool::Reset()
{
    m_temp_added.clear();
    m_non_base_coins.clear();
}

size_t CTxMemPool::DynamicMemoryUsage() const {
    LOCK(cs);
    // Estimate the overhead of mapTx to be 15 pointers + an allocation, as no exact formula for boost::multi_index_contained is implemented.
    return memusage::MallocUsage(sizeof(CTxMemPoolEntry) + 15 * sizeof(void*)) * mapTx.size() + memusage::DynamicUsage(mapNextTx) + memusage::DynamicUsage(mapDeltas) + memusage::DynamicUsage(txns_randomized) + cachedInnerUsage;
}

void CTxMemPool::RemoveUnbroadcastTx(const uint256& txid, const bool unchecked) {
    LOCK(cs);

    if (m_unbroadcast_txids.erase(txid))
    {
        LogPrint(BCLog::MEMPOOL, "Removed %i from set of unbroadcast txns%s\n", txid.GetHex(), (unchecked ? " before confirmation that txn was sent out" : ""));
    }
}

void CTxMemPool::RemoveStaged(setEntries &stage, bool updateDescendants, MemPoolRemovalReason reason) {
    AssertLockHeld(cs);
    UpdateForRemoveFromMempool(stage, updateDescendants);
    for (txiter it : stage) {
        removeUnchecked(it, reason);
    }
}

int CTxMemPool::Expire(std::chrono::seconds time)
{
    AssertLockHeld(cs);
    indexed_transaction_set::index<entry_time>::type::iterator it = mapTx.get<entry_time>().begin();
    setEntries toremove;
    while (it != mapTx.get<entry_time>().end() && it->GetTime() < time) {
        toremove.insert(mapTx.project<0>(it));
        it++;
    }
    setEntries stage;
    for (txiter removeit : toremove) {
        CalculateDescendants(removeit, stage);
    }
    RemoveStaged(stage, false, MemPoolRemovalReason::EXPIRY);
    return stage.size();
}

void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry)
{
    auto ancestors{AssumeCalculateMemPoolAncestors(__func__, entry, Limits::NoLimits())};
    return addUnchecked(entry, ancestors);
}

void CTxMemPool::UpdateChild(txiter entry, txiter child, bool add)
{
    AssertLockHeld(cs);
    CTxMemPoolEntry::Children s;
    if (add && entry->GetMemPoolChildren().insert(*child).second) {
        cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
    } else if (!add && entry->GetMemPoolChildren().erase(*child)) {
        cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
    }
}

void CTxMemPool::UpdateParent(txiter entry, txiter parent, bool add)
{
    AssertLockHeld(cs);
    CTxMemPoolEntry::Parents s;
    if (add && entry->GetMemPoolParents().insert(*parent).second) {
        cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
    } else if (!add && entry->GetMemPoolParents().erase(*parent)) {
        cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
    }
}

CFeeRate CTxMemPool::GetMinFee(size_t sizelimit) const {
    LOCK(cs);
    if (!blockSinceLastRollingFeeBump || rollingMinimumFeeRate == 0)
        return CFeeRate(llround(rollingMinimumFeeRate));

    int64_t time = GetTime();
    if (time > lastRollingFeeUpdate + 10) {
        double halflife = ROLLING_FEE_HALFLIFE;
        if (DynamicMemoryUsage() < sizelimit / 4)
            halflife /= 4;
        else if (DynamicMemoryUsage() < sizelimit / 2)
            halflife /= 2;

        rollingMinimumFeeRate = rollingMinimumFeeRate / pow(2.0, (time - lastRollingFeeUpdate) / halflife);
        lastRollingFeeUpdate = time;

        if (rollingMinimumFeeRate < (double)m_incremental_relay_feerate.GetFeePerK() / 2) {
            rollingMinimumFeeRate = 0;
            return CFeeRate(0);
        }
    }
    return std::max(CFeeRate(llround(rollingMinimumFeeRate)), m_incremental_relay_feerate);
}

void CTxMemPool::trackPackageRemoved(const CFeeRate& rate) {
    AssertLockHeld(cs);
    if (rate.GetFeePerK() > rollingMinimumFeeRate) {
        rollingMinimumFeeRate = rate.GetFeePerK();
        blockSinceLastRollingFeeBump = false;
    }
}

void CTxMemPool::TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpendsRemaining) {
    AssertLockHeld(cs);

    unsigned nTxnRemoved = 0;
    CFeeRate maxFeeRateRemoved(0);
    while (!mapTx.empty() && DynamicMemoryUsage() > sizelimit) {
        indexed_transaction_set::index<descendant_score>::type::iterator it = mapTx.get<descendant_score>().begin();

        // We set the new mempool min fee to the feerate of the removed set, plus the
        // "minimum reasonable fee rate" (ie some value under which we consider txn
        // to have 0 fee). This way, we don't allow txn to enter mempool with feerate
        // equal to txn which were removed with no block in between.
        CFeeRate removed(it->GetModFeesWithDescendants(), it->GetSizeWithDescendants());
        removed += m_incremental_relay_feerate;
        trackPackageRemoved(removed);
        maxFeeRateRemoved = std::max(maxFeeRateRemoved, removed);

        setEntries stage;
        CalculateDescendants(mapTx.project<0>(it), stage);
        nTxnRemoved += stage.size();

        std::vector<CTransaction> txn;
        if (pvNoSpendsRemaining) {
            txn.reserve(stage.size());
            for (txiter iter : stage)
                txn.push_back(iter->GetTx());
        }
        RemoveStaged(stage, false, MemPoolRemovalReason::SIZELIMIT);
        if (pvNoSpendsRemaining) {
            for (const CTransaction& tx : txn) {
                for (const CTxIn& txin : tx.vin) {
                    if (exists(GenTxid::Txid(txin.prevout.hash))) continue;
                    pvNoSpendsRemaining->push_back(txin.prevout);
                }
            }
        }
    }

    if (maxFeeRateRemoved > CFeeRate(0)) {
        LogPrint(BCLog::MEMPOOL, "Removed %u txn, rolling minimum fee bumped to %s\n", nTxnRemoved, maxFeeRateRemoved.ToString());
    }
}

uint64_t CTxMemPool::CalculateDescendantMaximum(txiter entry) const {
    // find parent with highest descendant count
    std::vector<txiter> candidates;
    setEntries counted;
    candidates.push_back(entry);
    uint64_t maximum = 0;
    while (candidates.size()) {
        txiter candidate = candidates.back();
        candidates.pop_back();
        if (!counted.insert(candidate).second) continue;
        const CTxMemPoolEntry::Parents& parents = candidate->GetMemPoolParentsConst();
        if (parents.size() == 0) {
            maximum = std::max(maximum, candidate->GetCountWithDescendants());
        } else {
            for (const CTxMemPoolEntry& i : parents) {
                candidates.push_back(mapTx.iterator_to(i));
            }
        }
    }
    return maximum;
}

void CTxMemPool::GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants, size_t* const ancestorsize, CAmount* const ancestorfees) const {
    LOCK(cs);
    auto it = mapTx.find(txid);
    ancestors = descendants = 0;
    if (it != mapTx.end()) {
        ancestors = it->GetCountWithAncestors();
        if (ancestorsize) *ancestorsize = it->GetSizeWithAncestors();
        if (ancestorfees) *ancestorfees = it->GetModFeesWithAncestors();
        descendants = CalculateDescendantMaximum(it);
    }
}

bool CTxMemPool::GetLoadTried() const
{
    LOCK(cs);
    return m_load_tried;
}

void CTxMemPool::SetLoadTried(bool load_tried)
{
    LOCK(cs);
    m_load_tried = load_tried;
}

std::vector<CTxMemPool::txiter> CTxMemPool::GatherClusters(const std::vector<uint256>& txids) const
{
    AssertLockHeld(cs);
    std::vector<txiter> clustered_txs{GetIterVec(txids)};
    // Use epoch: visiting an entry means we have added it to the clustered_txs vector. It does not
    // necessarily mean the entry has been processed.
    WITH_FRESH_EPOCH(m_epoch);
    for (const auto& it : clustered_txs) {
        visited(it);
    }
    // i = index of where the list of entries to process starts
    for (size_t i{0}; i < clustered_txs.size(); ++i) {
        // DoS protection: if there are 500 or more entries to process, just quit.
        if (clustered_txs.size() > 500) return {};
        const txiter& tx_iter = clustered_txs.at(i);
        for (const auto& entries : {tx_iter->GetMemPoolParentsConst(), tx_iter->GetMemPoolChildrenConst()}) {
            for (const CTxMemPoolEntry& entry : entries) {
                const auto entry_it = mapTx.iterator_to(entry);
                if (!visited(entry_it)) {
                    clustered_txs.push_back(entry_it);
                }
            }
        }
    }
    return clustered_txs;
}

std::optional<std::string> CTxMemPool::CheckConflictTopology(const setEntries& direct_conflicts)
{
    for (const auto& direct_conflict : direct_conflicts) {
        // Ancestor and descendant counts are inclusive of the tx itself.
        const auto ancestor_count{direct_conflict->GetCountWithAncestors()};
        const auto descendant_count{direct_conflict->GetCountWithDescendants()};
        const bool has_ancestor{ancestor_count > 1};
        const bool has_descendant{descendant_count > 1};
        const auto& txid_string{direct_conflict->GetSharedTx()->GetHash().ToString()};
        // The only allowed configurations are:
        // 1 ancestor and 0 descendant
        // 0 ancestor and 1 descendant
        // 0 ancestor and 0 descendant
        if (ancestor_count > 2) {
            return strprintf("%s has %u ancestors, max 1 allowed", txid_string, ancestor_count - 1);
        } else if (descendant_count > 2) {
            return strprintf("%s has %u descendants, max 1 allowed", txid_string, descendant_count - 1);
        } else if (has_ancestor && has_descendant) {
            return strprintf("%s has both ancestor and descendant, exceeding cluster limit of 2", txid_string);
        }
        // Additionally enforce that:
        // If we have a child,  we are its only parent.
        // If we have a parent, we are its only child.
        if (has_descendant) {
            const auto& our_child = direct_conflict->GetMemPoolChildrenConst().begin();
            if (our_child->get().GetCountWithAncestors() > 2) {
                return strprintf("%s is not the only parent of child %s",
                                 txid_string, our_child->get().GetSharedTx()->GetHash().ToString());
            }
        } else if (has_ancestor) {
            const auto& our_parent = direct_conflict->GetMemPoolParentsConst().begin();
            if (our_parent->get().GetCountWithDescendants() > 2) {
                return strprintf("%s is not the only child of parent %s",
                                 txid_string, our_parent->get().GetSharedTx()->GetHash().ToString());
            }
        }
    }
    return std::nullopt;
}

util::Result<std::pair<std::vector<FeeFrac>, std::vector<FeeFrac>>> CTxMemPool::CalculateFeerateDiagramsForRBF(CAmount replacement_fees, int64_t replacement_vsize, const setEntries& direct_conflicts, const setEntries& all_conflicts)
{
    Assume(replacement_vsize > 0);

    auto err_string{CheckConflictTopology(direct_conflicts)};
    if (err_string.has_value()) {
        // Unsupported topology for calculating a feerate diagram
        return util::Error{Untranslated(err_string.value())};
    }

    // new diagram will have chunks that consist of each ancestor of
    // direct_conflicts that is at its own fee/size, along with the replacement
    // tx/package at its own fee/size

    // old diagram will consist of the ancestors and descendants of each element of
    // all_conflicts.  every such transaction will either be at its own feerate (followed
    // by any descendant at its own feerate), or as a single chunk at the descendant's
    // ancestor feerate.

    std::vector<FeeFrac> old_chunks;
    // Step 1: build the old diagram.

    // The above clusters are all trivially linearized;
    // they have a strict topology of 1 or two connected transactions.

    // OLD: Compute existing chunks from all affected clusters
    for (auto txiter : all_conflicts) {
        // Does this transaction have descendants?
        if (txiter->GetCountWithDescendants() > 1) {
            // Consider this tx when we consider the descendant.
            continue;
        }
        // Does this transaction have ancestors?
        FeeFrac individual{txiter->GetModifiedFee(), txiter->GetTxSize()};
        if (txiter->GetCountWithAncestors() > 1) {
            // We'll add chunks for either the ancestor by itself and this tx
            // by itself, or for a combined package.
            FeeFrac package{txiter->GetModFeesWithAncestors(), static_cast<int32_t>(txiter->GetSizeWithAncestors())};
            if (individual >> package) {
                // The individual feerate is higher than the package, and
                // therefore higher than the parent's fee. Chunk these
                // together.
                old_chunks.emplace_back(package);
            } else {
                // Add two points, one for the parent and one for this child.
                old_chunks.emplace_back(package - individual);
                old_chunks.emplace_back(individual);
            }
        } else {
            old_chunks.emplace_back(individual);
        }
    }

    // No topology restrictions post-chunking; sort
    std::sort(old_chunks.begin(), old_chunks.end(), std::greater());
    std::vector<FeeFrac> old_diagram = BuildDiagramFromChunks(old_chunks);

    std::vector<FeeFrac> new_chunks;

    /* Step 2: build the NEW diagram
     * CON = Conflicts of proposed chunk
     * CNK = Proposed chunk
     * NEW = OLD - CON + CNK: New diagram includes all chunks in OLD, minus
     * the conflicts, plus the proposed chunk
     */

    // OLD - CON: Add any parents of direct conflicts that are not conflicted themselves
    for (auto direct_conflict : direct_conflicts) {
        // If a direct conflict has an ancestor that is not in all_conflicts,
        // it can be affected by the replacement of the child.
        if (direct_conflict->GetMemPoolParentsConst().size() > 0) {
            // Grab the parent.
            const CTxMemPoolEntry& parent = direct_conflict->GetMemPoolParentsConst().begin()->get();
            if (!all_conflicts.count(mapTx.iterator_to(parent))) {
                // This transaction would be left over, so add to the NEW
                // diagram.
                new_chunks.emplace_back(parent.GetModifiedFee(), parent.GetTxSize());
            }
        }
    }
    // + CNK: Add the proposed chunk itself
    new_chunks.emplace_back(replacement_fees, int32_t(replacement_vsize));

    // No topology restrictions post-chunking; sort
    std::sort(new_chunks.begin(), new_chunks.end(), std::greater());
    std::vector<FeeFrac> new_diagram = BuildDiagramFromChunks(new_chunks);
    return std::make_pair(old_diagram, new_diagram);
}