summaryrefslogtreecommitdiff
path: root/fetch-pack.c
blob: f93723fec41c772db0c0d6f5a8bb2239c9d370bd (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
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
#include "cache.h"
#include "repository.h"
#include "config.h"
#include "lockfile.h"
#include "refs.h"
#include "pkt-line.h"
#include "commit.h"
#include "tag.h"
#include "exec-cmd.h"
#include "pack.h"
#include "sideband.h"
#include "fetch-pack.h"
#include "remote.h"
#include "run-command.h"
#include "connect.h"
#include "transport.h"
#include "version.h"
#include "prio-queue.h"
#include "sha1-array.h"
#include "oidset.h"
#include "packfile.h"
 
static int transfer_unpack_limit = -1;
static int fetch_unpack_limit = -1;
static int unpack_limit = 100;
static int prefer_ofs_delta = 1;
static int no_done;
static int deepen_since_ok;
static int deepen_not_ok;
static int fetch_fsck_objects = -1;
static int transfer_fsck_objects = -1;
static int agent_supported;
static int server_supports_filtering;
static struct lock_file shallow_lock;
static const char *alternate_shallow_file;
 
/* Remember to update object flag allocation in object.h */
#define COMPLETE	(1U << 0)
#define COMMON		(1U << 1)
#define COMMON_REF	(1U << 2)
#define SEEN		(1U << 3)
#define POPPED		(1U << 4)
#define ALTERNATE	(1U << 5)
 
static int marked;
 
/*
 * After sending this many "have"s if we do not get any new ACK , we
 * give up traversing our history.
 */
#define MAX_IN_VAIN 256
 
static struct prio_queue rev_list = { compare_commits_by_commit_date };
static int non_common_revs, multi_ack, use_sideband;
/* Allow specifying sha1 if it is a ref tip. */
#define ALLOW_TIP_SHA1	01
/* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
#define ALLOW_REACHABLE_SHA1	02
static unsigned int allow_unadvertised_object_request;
 
__attribute__((format (printf, 2, 3)))
static inline void print_verbose(const struct fetch_pack_args *args,
				 const char *fmt, ...)
{
	va_list params;
 
	if (!args->verbose)
		return;
 
	va_start(params, fmt);
	vfprintf(stderr, fmt, params);
	va_end(params);
	fputc('\n', stderr);
}
 
struct alternate_object_cache {
	struct object **items;
	size_t nr, alloc;
};
 
static void cache_one_alternate(const char *refname,
				const struct object_id *oid,
				void *vcache)
{
	struct alternate_object_cache *cache = vcache;
	struct object *obj = parse_object(oid);
 
	if (!obj || (obj->flags & ALTERNATE))
		return;
 
	obj->flags |= ALTERNATE;
	ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
	cache->items[cache->nr++] = obj;
}
 
static void for_each_cached_alternate(void (*cb)(struct object *))
{
	static int initialized;
	static struct alternate_object_cache cache;
	size_t i;
 
	if (!initialized) {
		for_each_alternate_ref(cache_one_alternate, &cache);
		initialized = 1;
	}
 
	for (i = 0; i < cache.nr; i++)
		cb(cache.items[i]);
}
 
static void rev_list_push(struct commit *commit, int mark)
{
	if (!(commit->object.flags & mark)) {
		commit->object.flags |= mark;
 
		if (parse_commit(commit))
			return;
 
		prio_queue_put(&rev_list, commit);
 
		if (!(commit->object.flags & COMMON))
			non_common_revs++;
	}
}
 
static int rev_list_insert_ref(const char *refname, const struct object_id *oid)
{
	struct object *o = deref_tag(parse_object(oid), refname, 0);
 
	if (o && o->type == OBJ_COMMIT)
		rev_list_push((struct commit *)o, SEEN);
 
	return 0;
}
 
static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
				   int flag, void *cb_data)
{
	return rev_list_insert_ref(refname, oid);
}
 
static int clear_marks(const char *refname, const struct object_id *oid,
		       int flag, void *cb_data)
{
	struct object *o = deref_tag(parse_object(oid), refname, 0);
 
	if (o && o->type == OBJ_COMMIT)
		clear_commit_marks((struct commit *)o,
				   COMMON | COMMON_REF | SEEN | POPPED);
	return 0;
}
 
/*
   This function marks a rev and its ancestors as common.
   In some cases, it is desirable to mark only the ancestors (for example
   when only the server does not yet know that they are common).
*/
 
static void mark_common(struct commit *commit,
		int ancestors_only, int dont_parse)
{
	if (commit != NULL && !(commit->object.flags & COMMON)) {
		struct object *o = (struct object *)commit;
 
		if (!ancestors_only)
			o->flags |= COMMON;
 
		if (!(o->flags & SEEN))
			rev_list_push(commit, SEEN);
		else {
			struct commit_list *parents;
 
			if (!ancestors_only && !(o->flags & POPPED))
				non_common_revs--;
			if (!o->parsed && !dont_parse)
				if (parse_commit(commit))
					return;
 
			for (parents = commit->parents;
					parents;
					parents = parents->next)
				mark_common(parents->item, 0, dont_parse);
		}
	}
}
 
/*
  Get the next rev to send, ignoring the common.
*/
 
static const struct object_id *get_rev(void)
{
	struct commit *commit = NULL;
 
	while (commit == NULL) {
		unsigned int mark;
		struct commit_list *parents;
 
		if (rev_list.nr == 0 || non_common_revs == 0)
			return NULL;
 
		commit = prio_queue_get(&rev_list);
		parse_commit(commit);
		parents = commit->parents;
 
		commit->object.flags |= POPPED;
		if (!(commit->object.flags & COMMON))
			non_common_revs--;
 
		if (commit->object.flags & COMMON) {
			/* do not send "have", and ignore ancestors */
			commit = NULL;
			mark = COMMON | SEEN;
		} else if (commit->object.flags & COMMON_REF)
			/* send "have", and ignore ancestors */
			mark = COMMON | SEEN;
		else
			/* send "have", also for its ancestors */
			mark = SEEN;
 
		while (parents) {
			if (!(parents->item->object.flags & SEEN))
				rev_list_push(parents->item, mark);
			if (mark & COMMON)
				mark_common(parents->item, 1, 0);
			parents = parents->next;
		}
	}
 
	return &commit->object.oid;
}
 
enum ack_type {
	NAK = 0,
	ACK,
	ACK_continue,
	ACK_common,
	ACK_ready
};
 
static void consume_shallow_list(struct fetch_pack_args *args, int fd)
{
	if (args->stateless_rpc && args->deepen) {
		/* If we sent a depth we will get back "duplicate"
		 * shallow and unshallow commands every time there
		 * is a block of have lines exchanged.
		 */
		char *line;
		while ((line = packet_read_line(fd, NULL))) {
			if (starts_with(line, "shallow "))
				continue;
			if (starts_with(line, "unshallow "))
				continue;
			die(_("git fetch-pack: expected shallow list"));
		}
	}
}
 
static enum ack_type get_ack(int fd, struct object_id *result_oid)
{
	int len;
	char *line = packet_read_line(fd, &len);
	const char *arg;
 
	if (!line)
		die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
	if (!strcmp(line, "NAK"))
		return NAK;
	if (skip_prefix(line, "ACK ", &arg)) {
		if (!get_oid_hex(arg, result_oid)) {
			arg += 40;
			len -= arg - line;
			if (len < 1)
				return ACK;
			if (strstr(arg, "continue"))
				return ACK_continue;
			if (strstr(arg, "common"))
				return ACK_common;
			if (strstr(arg, "ready"))
				return ACK_ready;
			return ACK;
		}
	}
	if (skip_prefix(line, "ERR ", &arg))
		die(_("remote error: %s"), arg);
	die(_("git fetch-pack: expected ACK/NAK, got '%s'"), line);
}
 
static void send_request(struct fetch_pack_args *args,
			 int fd, struct strbuf *buf)
{
	if (args->stateless_rpc) {
		send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
		packet_flush(fd);
	} else
		write_or_die(fd, buf->buf, buf->len);
}
 
static void insert_one_alternate_object(struct object *obj)
{
	rev_list_insert_ref(NULL, &obj->oid);
}
 
#define INITIAL_FLUSH 16
#define PIPESAFE_FLUSH 32
#define LARGE_FLUSH 16384
 
static int next_flush(int stateless_rpc, int count)
{
	if (stateless_rpc) {
		if (count < LARGE_FLUSH)
			count <<= 1;
		else
			count = count * 11 / 10;
	} else {
		if (count < PIPESAFE_FLUSH)
			count <<= 1;
		else
			count += PIPESAFE_FLUSH;
	}
	return count;
}
 
static int find_common(struct fetch_pack_args *args,
		       int fd[2], struct object_id *result_oid,
		       struct ref *refs)
{
	int fetching;
	int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
	const struct object_id *oid;
	unsigned in_vain = 0;
	int got_continue = 0;
	int got_ready = 0;
	struct strbuf req_buf = STRBUF_INIT;
	size_t state_len = 0;
 
	if (args->stateless_rpc && multi_ack == 1)
		die(_("--stateless-rpc requires multi_ack_detailed"));
	if (marked)
		for_each_ref(clear_marks, NULL);
	marked = 1;
 
	for_each_ref(rev_list_insert_ref_oid, NULL);
	for_each_cached_alternate(insert_one_alternate_object);
 
	fetching = 0;
	for ( ; refs ; refs = refs->next) {
		struct object_id *remote = &refs->old_oid;
		const char *remote_hex;
		struct object *o;
 
		/*
		 * If that object is complete (i.e. it is an ancestor of a
		 * local ref), we tell them we have it but do not have to
		 * tell them about its ancestors, which they already know
		 * about.
		 *
		 * We use lookup_object here because we are only
		 * interested in the case we *know* the object is
		 * reachable and we have already scanned it.
		 */
		if (((o = lookup_object(remote->hash)) != NULL) &&
				(o->flags & COMPLETE)) {
			continue;
		}
 
		remote_hex = oid_to_hex(remote);
		if (!fetching) {
			struct strbuf c = STRBUF_INIT;
			if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
			if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
			if (no_done)            strbuf_addstr(&c, " no-done");
			if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
			if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
			if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
			if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
			if (args->no_progress)   strbuf_addstr(&c, " no-progress");
			if (args->include_tag)   strbuf_addstr(&c, " include-tag");
			if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
			if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
			if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
			if (agent_supported)    strbuf_addf(&c, " agent=%s",
							    git_user_agent_sanitized());
			if (args->filter_options.choice)
				strbuf_addstr(&c, " filter");
			packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
			strbuf_release(&c);
		} else
			packet_buf_write(&req_buf, "want %s\n", remote_hex);
		fetching++;
	}
 
	if (!fetching) {
		strbuf_release(&req_buf);
		packet_flush(fd[1]);
		return 1;
	}
 
	if (is_repository_shallow())
		write_shallow_commits(&req_buf, 1, NULL);
	if (args->depth > 0)
		packet_buf_write(&req_buf, "deepen %d", args->depth);
	if (args->deepen_since) {
		timestamp_t max_age = approxidate(args->deepen_since);
		packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
	}
	if (args->deepen_not) {
		int i;
		for (i = 0; i < args->deepen_not->nr; i++) {
			struct string_list_item *s = args->deepen_not->items + i;
			packet_buf_write(&req_buf, "deepen-not %s", s->string);
		}
	}
	if (server_supports_filtering && args->filter_options.choice)
		packet_buf_write(&req_buf, "filter %s",
				 args->filter_options.filter_spec);
	packet_buf_flush(&req_buf);
	state_len = req_buf.len;
 
	if (args->deepen) {
		char *line;
		const char *arg;
		struct object_id oid;
 
		send_request(args, fd[1], &req_buf);
		while ((line = packet_read_line(fd[0], NULL))) {
			if (skip_prefix(line, "shallow ", &arg)) {
				if (get_oid_hex(arg, &oid))
					die(_("invalid shallow line: %s"), line);
				register_shallow(&oid);
				continue;
			}
			if (skip_prefix(line, "unshallow ", &arg)) {
				if (get_oid_hex(arg, &oid))
					die(_("invalid unshallow line: %s"), line);
				if (!lookup_object(oid.hash))
					die(_("object not found: %s"), line);
				/* make sure that it is parsed as shallow */
				if (!parse_object(&oid))
					die(_("error in object: %s"), line);
				if (unregister_shallow(&oid))
					die(_("no shallow found: %s"), line);
				continue;
			}
			die(_("expected shallow/unshallow, got %s"), line);
		}
	} else if (!args->stateless_rpc)
		send_request(args, fd[1], &req_buf);
 
	if (!args->stateless_rpc) {
		/* If we aren't using the stateless-rpc interface
		 * we don't need to retain the headers.
		 */
		strbuf_setlen(&req_buf, 0);
		state_len = 0;
	}
 
	flushes = 0;
	retval = -1;
	if (args->no_dependents)
		goto done;
	while ((oid = get_rev())) {
		packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
		print_verbose(args, "have %s", oid_to_hex(oid));
		in_vain++;
		if (flush_at <= ++count) {
			int ack;
 
			packet_buf_flush(&req_buf);
			send_request(args, fd[1], &req_buf);
			strbuf_setlen(&req_buf, state_len);
			flushes++;
			flush_at = next_flush(args->stateless_rpc, count);
 
			/*
			 * We keep one window "ahead" of the other side, and
			 * will wait for an ACK only on the next one
			 */
			if (!args->stateless_rpc && count == INITIAL_FLUSH)
				continue;
 
			consume_shallow_list(args, fd[0]);
			do {
				ack = get_ack(fd[0], result_oid);
				if (ack)
					print_verbose(args, _("got %s %d %s"), "ack",
						      ack, oid_to_hex(result_oid));
				switch (ack) {
				case ACK:
					flushes = 0;
					multi_ack = 0;
					retval = 0;
					goto done;
				case ACK_common:
				case ACK_ready:
				case ACK_continue: {
					struct commit *commit =
						lookup_commit(result_oid);
					if (!commit)
						die(_("invalid commit %s"), oid_to_hex(result_oid));
					if (args->stateless_rpc
					 && ack == ACK_common
					 && !(commit->object.flags & COMMON)) {
						/* We need to replay the have for this object
						 * on the next RPC request so the peer knows
						 * it is in common with us.
						 */
						const char *hex = oid_to_hex(result_oid);
						packet_buf_write(&req_buf, "have %s\n", hex);
						state_len = req_buf.len;
						/*
						 * Reset in_vain because an ack
						 * for this commit has not been
						 * seen.
						 */
						in_vain = 0;
					} else if (!args->stateless_rpc
						   || ack != ACK_common)
						in_vain = 0;
					mark_common(commit, 0, 1);
					retval = 0;
					got_continue = 1;
					if (ack == ACK_ready) {
						clear_prio_queue(&rev_list);
						got_ready = 1;
					}
					break;
					}
				}
			} while (ack);
			flushes--;
			if (got_continue && MAX_IN_VAIN < in_vain) {
				print_verbose(args, _("giving up"));
				break; /* give up */
			}
		}
	}
done:
	if (!got_ready || !no_done) {
		packet_buf_write(&req_buf, "done\n");
		send_request(args, fd[1], &req_buf);
	}
	print_verbose(args, _("done"));
	if (retval != 0) {
		multi_ack = 0;
		flushes++;
	}
	strbuf_release(&req_buf);
 
	if (!got_ready || !no_done)
		consume_shallow_list(args, fd[0]);
	while (flushes || multi_ack) {
		int ack = get_ack(fd[0], result_oid);
		if (ack) {
			print_verbose(args, _("got %s (%d) %s"), "ack",
				      ack, oid_to_hex(result_oid));
			if (ack == ACK)
				return 0;
			multi_ack = 1;
			continue;
		}
		flushes--;
	}
	/* it is no error to fetch into a completely empty repo */
	return count ? retval : 0;
}
 
static struct commit_list *complete;
 
static int mark_complete(const struct object_id *oid)
{
	struct object *o = parse_object(oid);
 
	while (o && o->type == OBJ_TAG) {
		struct tag *t = (struct tag *) o;
		if (!t->tagged)
			break; /* broken repository */
		o->flags |= COMPLETE;
		o = parse_object(&t->tagged->oid);
	}
	if (o && o->type == OBJ_COMMIT) {
		struct commit *commit = (struct commit *)o;
		if (!(commit->object.flags & COMPLETE)) {
			commit->object.flags |= COMPLETE;
			commit_list_insert(commit, &complete);
		}
	}
	return 0;
}
 
static int mark_complete_oid(const char *refname, const struct object_id *oid,
			     int flag, void *cb_data)
{
	return mark_complete(oid);
}
 
static void mark_recent_complete_commits(struct fetch_pack_args *args,
					 timestamp_t cutoff)
{
	while (complete && cutoff <= complete->item->date) {
		print_verbose(args, _("Marking %s as complete"),
			      oid_to_hex(&complete->item->object.oid));
		pop_most_recent_commit(&complete, COMPLETE);
	}
}
 
static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
{
	for (; refs; refs = refs->next)
		oidset_insert(oids, &refs->old_oid);
}
 
static int tip_oids_contain(struct oidset *tip_oids,
			    struct ref *unmatched, struct ref *newlist,
			    const struct object_id *id)
{
	/*
	 * Note that this only looks at the ref lists the first time it's
	 * called. This works out in filter_refs() because even though it may
	 * add to "newlist" between calls, the additions will always be for
	 * oids that are already in the set.
	 */
	if (!tip_oids->map.map.tablesize) {
		add_refs_to_oidset(tip_oids, unmatched);
		add_refs_to_oidset(tip_oids, newlist);
	}
	return oidset_contains(tip_oids, id);
}
 
static void filter_refs(struct fetch_pack_args *args,
			struct ref **refs,
			struct ref **sought, int nr_sought)
{
	struct ref *newlist = NULL;
	struct ref **newtail = &newlist;
	struct ref *unmatched = NULL;
	struct ref *ref, *next;
	struct oidset tip_oids = OIDSET_INIT;
	int i;
 
	i = 0;
	for (ref = *refs; ref; ref = next) {
		int keep = 0;
		next = ref->next;
 
		if (starts_with(ref->name, "refs/") &&
		    check_refname_format(ref->name, 0))
			; /* trash */
		else {
			while (i < nr_sought) {
				int cmp = strcmp(ref->name, sought[i]->name);
				if (cmp < 0)
					break; /* definitely do not have it */
				else if (cmp == 0) {
					keep = 1; /* definitely have it */
					sought[i]->match_status = REF_MATCHED;
				}
				i++;
			}
		}
 
		if (!keep && args->fetch_all &&
		    (!args->deepen || !starts_with(ref->name, "refs/tags/")))
			keep = 1;
 
		if (keep) {
			*newtail = ref;
			ref->next = NULL;
			newtail = &ref->next;
		} else {
			ref->next = unmatched;
			unmatched = ref;
		}
	}
 
	/* Append unmatched requests to the list */
	for (i = 0; i < nr_sought; i++) {
		struct object_id oid;
		const char *p;
 
		ref = sought[i];
		if (ref->match_status != REF_NOT_MATCHED)
			continue;
		if (parse_oid_hex(ref->name, &oid, &p) ||
		    *p != '\0' ||
		    oidcmp(&oid, &ref->old_oid))
			continue;
 
		if ((allow_unadvertised_object_request &
		     (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)) ||
		    tip_oids_contain(&tip_oids, unmatched, newlist,
				     &ref->old_oid)) {
			ref->match_status = REF_MATCHED;
			*newtail = copy_ref(ref);
			newtail = &(*newtail)->next;
		} else {
			ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
		}
	}
 
	oidset_clear(&tip_oids);
	for (ref = unmatched; ref; ref = next) {
		next = ref->next;
		free(ref);
	}
 
	*refs = newlist;
}
 
static void mark_alternate_complete(struct object *obj)
{
	mark_complete(&obj->oid);
}
 
struct loose_object_iter {
	struct oidset *loose_object_set;
	struct ref *refs;
};
 
/*
 *  If the number of refs is not larger than the number of loose objects,
 *  this function stops inserting.
 */
static int add_loose_objects_to_set(const struct object_id *oid,
				    const char *path,
				    void *data)
{
	struct loose_object_iter *iter = data;
	oidset_insert(iter->loose_object_set, oid);
	if (iter->refs == NULL)
		return 1;
 
	iter->refs = iter->refs->next;
	return 0;
}
 
static int everything_local(struct fetch_pack_args *args,
			    struct ref **refs,
			    struct ref **sought, int nr_sought)
{
	struct ref *ref;
	int retval;
	int old_save_commit_buffer = save_commit_buffer;
	timestamp_t cutoff = 0;
	struct oidset loose_oid_set = OIDSET_INIT;
	int use_oidset = 0;
	struct loose_object_iter iter = {&loose_oid_set, *refs};
 
	/* Enumerate all loose objects or know refs are not so many. */
	use_oidset = !for_each_loose_object(add_loose_objects_to_set,
					    &iter, 0);
 
	save_commit_buffer = 0;
 
	for (ref = *refs; ref; ref = ref->next) {
		struct object *o;
		unsigned int flags = OBJECT_INFO_QUICK;
 
		if (use_oidset &&
		    !oidset_contains(&loose_oid_set, &ref->old_oid)) {
			/*
			 * I know this does not exist in the loose form,
			 * so check if it exists in a non-loose form.
			 */
			flags |= OBJECT_INFO_IGNORE_LOOSE;
		}
 
		if (!has_object_file_with_flags(&ref->old_oid, flags))
			continue;
		o = parse_object(&ref->old_oid);
		if (!o)
			continue;
 
		/* We already have it -- which may mean that we were
		 * in sync with the other side at some time after
		 * that (it is OK if we guess wrong here).
		 */
		if (o->type == OBJ_COMMIT) {
			struct commit *commit = (struct commit *)o;
			if (!cutoff || cutoff < commit->date)
				cutoff = commit->date;
		}
	}
 
	oidset_clear(&loose_oid_set);
 
	if (!args->no_dependents) {
		if (!args->deepen) {
			for_each_ref(mark_complete_oid, NULL);
			for_each_cached_alternate(mark_alternate_complete);
			commit_list_sort_by_date(&complete);
			if (cutoff)
				mark_recent_complete_commits(args, cutoff);
		}
 
		/*
		 * Mark all complete remote refs as common refs.
		 * Don't mark them common yet; the server has to be told so first.
		 */
		for (ref = *refs; ref; ref = ref->next) {
			struct object *o = deref_tag(lookup_object(ref->old_oid.hash),
						     NULL, 0);
 
			if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
				continue;
 
			if (!(o->flags & SEEN)) {
				rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 
				mark_common((struct commit *)o, 1, 1);
			}
		}
	}
 
	filter_refs(args, refs, sought, nr_sought);
 
	for (retval = 1, ref = *refs; ref ; ref = ref->next) {
		const struct object_id *remote = &ref->old_oid;
		struct object *o;
 
		o = lookup_object(remote->hash);
		if (!o || !(o->flags & COMPLETE)) {
			retval = 0;
			print_verbose(args, "want %s (%s)", oid_to_hex(remote),
				      ref->name);
			continue;
		}
		print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
			      ref->name);
	}
 
	save_commit_buffer = old_save_commit_buffer;
 
	return retval;
}
 
static int sideband_demux(int in, int out, void *data)
{
	int *xd = data;
	int ret;
 
	ret = recv_sideband("fetch-pack", xd[0], out);
	close(out);
	return ret;
}
 
static int get_pack(struct fetch_pack_args *args,
		    int xd[2], char **pack_lockfile)
{
	struct async demux;
	int do_keep = args->keep_pack;
	const char *cmd_name;
	struct pack_header header;
	int pass_header = 0;
	struct child_process cmd = CHILD_PROCESS_INIT;
	int ret;
 
	memset(&demux, 0, sizeof(demux));
	if (use_sideband) {
		/* xd[] is talking with upload-pack; subprocess reads from
		 * xd[0], spits out band#2 to stderr, and feeds us band#1
		 * through demux->out.
		 */
		demux.proc = sideband_demux;
		demux.data = xd;
		demux.out = -1;
		demux.isolate_sigpipe = 1;
		if (start_async(&demux))
			die(_("fetch-pack: unable to fork off sideband demultiplexer"));
	}
	else
		demux.out = xd[0];
 
	if (!args->keep_pack && unpack_limit) {
 
		if (read_pack_header(demux.out, &header))
			die(_("protocol error: bad pack header"));
		pass_header = 1;
		if (ntohl(header.hdr_entries) < unpack_limit)
			do_keep = 0;
		else
			do_keep = 1;
	}
 
	if (alternate_shallow_file) {
		argv_array_push(&cmd.args, "--shallow-file");
		argv_array_push(&cmd.args, alternate_shallow_file);
	}
 
	if (do_keep || args->from_promisor) {
		if (pack_lockfile)
			cmd.out = -1;
		cmd_name = "index-pack";
		argv_array_push(&cmd.args, cmd_name);
		argv_array_push(&cmd.args, "--stdin");
		if (!args->quiet && !args->no_progress)
			argv_array_push(&cmd.args, "-v");
		if (args->use_thin_pack)
			argv_array_push(&cmd.args, "--fix-thin");
		if (do_keep && (args->lock_pack || unpack_limit)) {
			char hostname[HOST_NAME_MAX + 1];
			if (xgethostname(hostname, sizeof(hostname)))
				xsnprintf(hostname, sizeof(hostname), "localhost");
			argv_array_pushf(&cmd.args,
					"--keep=fetch-pack %"PRIuMAX " on %s",
					(uintmax_t)getpid(), hostname);
		}
		if (args->check_self_contained_and_connected)
			argv_array_push(&cmd.args, "--check-self-contained-and-connected");
		if (args->from_promisor)
			argv_array_push(&cmd.args, "--promisor");
	}
	else {
		cmd_name = "unpack-objects";
		argv_array_push(&cmd.args, cmd_name);
		if (args->quiet || args->no_progress)
			argv_array_push(&cmd.args, "-q");
		args->check_self_contained_and_connected = 0;
	}
 
	if (pass_header)
		argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
				 ntohl(header.hdr_version),
				 ntohl(header.hdr_entries));
	if (fetch_fsck_objects >= 0
	    ? fetch_fsck_objects
	    : transfer_fsck_objects >= 0
	    ? transfer_fsck_objects
	    : 0) {
		if (args->from_promisor)
			/*
			 * We cannot use --strict in index-pack because it
			 * checks both broken objects and links, but we only
			 * want to check for broken objects.
			 */
			argv_array_push(&cmd.args, "--fsck-objects");
		else
			argv_array_push(&cmd.args, "--strict");
	}
 
	cmd.in = demux.out;
	cmd.git_cmd = 1;
	if (start_command(&cmd))
		die(_("fetch-pack: unable to fork off %s"), cmd_name);
	if (do_keep && pack_lockfile) {
		*pack_lockfile = index_pack_lockfile(cmd.out);
		close(cmd.out);
	}
 
	if (!use_sideband)
		/* Closed by start_command() */
		xd[0] = -1;
 
	ret = finish_command(&cmd);
	if (!ret || (args->check_self_contained_and_connected && ret == 1))
		args->self_contained_and_connected =
			args->check_self_contained_and_connected &&
			ret == 0;
	else
		die(_("%s failed"), cmd_name);
	if (use_sideband && finish_async(&demux))
		die(_("error in sideband demultiplexer"));
	return 0;
}
 
static int cmp_ref_by_name(const void *a_, const void *b_)
{
	const struct ref *a = *((const struct ref **)a_);
	const struct ref *b = *((const struct ref **)b_);
	return strcmp(a->name, b->name);
}
 
static struct ref *do_fetch_pack(struct fetch_pack_args *args,
				 int fd[2],
				 const struct ref *orig_ref,
				 struct ref **sought, int nr_sought,
				 struct shallow_info *si,
				 char **pack_lockfile)
{
	struct ref *ref = copy_ref_list(orig_ref);
	struct object_id oid;
	const char *agent_feature;
	int agent_len;
 
	sort_ref_list(&ref, ref_compare_name);
	QSORT(sought, nr_sought, cmp_ref_by_name);
 
	if ((args->depth > 0 || is_repository_shallow()) && !server_supports("shallow"))
		die(_("Server does not support shallow clients"));
	if (args->depth > 0 || args->deepen_since || args->deepen_not)
		args->deepen = 1;
	if (server_supports("multi_ack_detailed")) {
		print_verbose(args, _("Server supports multi_ack_detailed"));
		multi_ack = 2;
		if (server_supports("no-done")) {
			print_verbose(args, _("Server supports no-done"));
			if (args->stateless_rpc)
				no_done = 1;
		}
	}
	else if (server_supports("multi_ack")) {
		print_verbose(args, _("Server supports multi_ack"));
		multi_ack = 1;
	}
	if (server_supports("side-band-64k")) {
		print_verbose(args, _("Server supports side-band-64k"));
		use_sideband = 2;
	}
	else if (server_supports("side-band")) {
		print_verbose(args, _("Server supports side-band"));
		use_sideband = 1;
	}
	if (server_supports("allow-tip-sha1-in-want")) {
		print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
		allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
	}
	if (server_supports("allow-reachable-sha1-in-want")) {
		print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
		allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
	}
	if (!server_supports("thin-pack"))
		args->use_thin_pack = 0;
	if (!server_supports("no-progress"))
		args->no_progress = 0;
	if (!server_supports("include-tag"))
		args->include_tag = 0;
	if (server_supports("ofs-delta"))
		print_verbose(args, _("Server supports ofs-delta"));
	else
		prefer_ofs_delta = 0;
 
	if (server_supports("filter")) {
		server_supports_filtering = 1;
		print_verbose(args, _("Server supports filter"));
	} else if (args->filter_options.choice) {
		warning("filtering not recognized by server, ignoring");
	}
 
	if ((agent_feature = server_feature_value("agent", &agent_len))) {
		agent_supported = 1;
		if (agent_len)
			print_verbose(args, _("Server version is %.*s"),
				      agent_len, agent_feature);
	}
	if (server_supports("deepen-since"))
		deepen_since_ok = 1;
	else if (args->deepen_since)
		die(_("Server does not support --shallow-since"));
	if (server_supports("deepen-not"))
		deepen_not_ok = 1;
	else if (args->deepen_not)
		die(_("Server does not support --shallow-exclude"));
	if (!server_supports("deepen-relative") && args->deepen_relative)
		die(_("Server does not support --deepen"));
 
	if (everything_local(args, &ref, sought, nr_sought)) {
		packet_flush(fd[1]);
		goto all_done;
	}
	if (find_common(args, fd, &oid, ref) < 0)
		if (!args->keep_pack)
			/* When cloning, it is not unusual to have
			 * no common commit.
			 */
			warning(_("no common commits"));
 
	if (args->stateless_rpc)
		packet_flush(fd[1]);
	if (args->deepen)
		setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
					NULL);
	else if (si->nr_ours || si->nr_theirs)
		alternate_shallow_file = setup_temporary_shallow(si->shallow);
	else
		alternate_shallow_file = NULL;
	if (get_pack(args, fd, pack_lockfile))
		die(_("git fetch-pack: fetch failed."));
 
 all_done:
	return ref;
}
 
static void add_shallow_requests(struct strbuf *req_buf,
				 const struct fetch_pack_args *args)
{
	if (is_repository_shallow())
		write_shallow_commits(req_buf, 1, NULL);
	if (args->depth > 0)
		packet_buf_write(req_buf, "deepen %d", args->depth);
	if (args->deepen_since) {
		timestamp_t max_age = approxidate(args->deepen_since);
		packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
	}
	if (args->deepen_not) {
		int i;
		for (i = 0; i < args->deepen_not->nr; i++) {
			struct string_list_item *s = args->deepen_not->items + i;
			packet_buf_write(req_buf, "deepen-not %s", s->string);
		}
	}
}
 
static void add_wants(const struct ref *wants, struct strbuf *req_buf)
{
	for ( ; wants ; wants = wants->next) {
		const struct object_id *remote = &wants->old_oid;
		const char *remote_hex;
		struct object *o;
 
		/*
		 * If that object is complete (i.e. it is an ancestor of a
		 * local ref), we tell them we have it but do not have to
		 * tell them about its ancestors, which they already know
		 * about.
		 *
		 * We use lookup_object here because we are only
		 * interested in the case we *know* the object is
		 * reachable and we have already scanned it.
		 */
		if (((o = lookup_object(remote->hash)) != NULL) &&
		    (o->flags & COMPLETE)) {
			continue;
		}
 
		remote_hex = oid_to_hex(remote);
		packet_buf_write(req_buf, "want %s\n", remote_hex);
	}
}
 
static void add_common(struct strbuf *req_buf, struct oidset *common)
{
	struct oidset_iter iter;
	const struct object_id *oid;
	oidset_iter_init(common, &iter);
 
	while ((oid = oidset_iter_next(&iter))) {
		packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
	}
}
 
static int add_haves(struct strbuf *req_buf, int *haves_to_send, int *in_vain)
{
	int ret = 0;
	int haves_added = 0;
	const struct object_id *oid;
 
	while ((oid = get_rev())) {
		packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
		if (++haves_added >= *haves_to_send)
			break;
	}
 
	*in_vain += haves_added;
	if (!haves_added || *in_vain >= MAX_IN_VAIN) {
		/* Send Done */
		packet_buf_write(req_buf, "done\n");
		ret = 1;
	}
 
	/* Increase haves to send on next round */
	*haves_to_send = next_flush(1, *haves_to_send);
 
	return ret;
}
 
static int send_fetch_request(int fd_out, const struct fetch_pack_args *args,
			      const struct ref *wants, struct oidset *common,
			      int *haves_to_send, int *in_vain)
{
	int ret = 0;
	struct strbuf req_buf = STRBUF_INIT;
 
	if (server_supports_v2("fetch", 1))
		packet_buf_write(&req_buf, "command=fetch");
	if (server_supports_v2("agent", 0))
		packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
 
	packet_buf_delim(&req_buf);
	if (args->use_thin_pack)
		packet_buf_write(&req_buf, "thin-pack");
	if (args->no_progress)
		packet_buf_write(&req_buf, "no-progress");
	if (args->include_tag)
		packet_buf_write(&req_buf, "include-tag");
	if (prefer_ofs_delta)
		packet_buf_write(&req_buf, "ofs-delta");
 
	/* Add shallow-info and deepen request */
	if (server_supports_feature("fetch", "shallow", 0))
		add_shallow_requests(&req_buf, args);
	else if (is_repository_shallow() || args->deepen)
		die(_("Server does not support shallow requests"));
 
	/* add wants */
	add_wants(wants, &req_buf);
 
	/* Add all of the common commits we've found in previous rounds */
	add_common(&req_buf, common);
 
	/* Add initial haves */
	ret = add_haves(&req_buf, haves_to_send, in_vain);
 
	/* Send request */
	packet_buf_flush(&req_buf);
	write_or_die(fd_out, req_buf.buf, req_buf.len);
 
	strbuf_release(&req_buf);
	return ret;
}
 
/*
 * Processes a section header in a server's response and checks if it matches
 * `section`.  If the value of `peek` is 1, the header line will be peeked (and
 * not consumed); if 0, the line will be consumed and the function will die if
 * the section header doesn't match what was expected.
 */
static int process_section_header(struct packet_reader *reader,
				  const char *section, int peek)
{
	int ret;
 
	if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
		die("error reading section header '%s'", section);
 
	ret = !strcmp(reader->line, section);
 
	if (!peek) {
		if (!ret)
			die("expected '%s', received '%s'",
			    section, reader->line);
		packet_reader_read(reader);
	}
 
	return ret;
}
 
static int process_acks(struct packet_reader *reader, struct oidset *common)
{
	/* received */
	int received_ready = 0;
	int received_ack = 0;
 
	process_section_header(reader, "acknowledgments", 0);
	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
		const char *arg;
 
		if (!strcmp(reader->line, "NAK"))
			continue;
 
		if (skip_prefix(reader->line, "ACK ", &arg)) {
			struct object_id oid;
			if (!get_oid_hex(arg, &oid)) {
				struct commit *commit;
				oidset_insert(common, &oid);
				commit = lookup_commit(&oid);
				mark_common(commit, 0, 1);
			}
			continue;
		}
 
		if (!strcmp(reader->line, "ready")) {
			clear_prio_queue(&rev_list);
			received_ready = 1;
			continue;
		}
 
		die("unexpected acknowledgment line: '%s'", reader->line);
	}
 
	if (reader->status != PACKET_READ_FLUSH &&
	    reader->status != PACKET_READ_DELIM)
		die("error processing acks: %d", reader->status);
 
	/* return 0 if no common, 1 if there are common, or 2 if ready */
	return received_ready ? 2 : (received_ack ? 1 : 0);
}
 
static void receive_shallow_info(struct fetch_pack_args *args,
				 struct packet_reader *reader)
{
	process_section_header(reader, "shallow-info", 0);
	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
		const char *arg;
		struct object_id oid;
 
		if (skip_prefix(reader->line, "shallow ", &arg)) {
			if (get_oid_hex(arg, &oid))
				die(_("invalid shallow line: %s"), reader->line);
			register_shallow(&oid);
			continue;
		}
		if (skip_prefix(reader->line, "unshallow ", &arg)) {
			if (get_oid_hex(arg, &oid))
				die(_("invalid unshallow line: %s"), reader->line);
			if (!lookup_object(oid.hash))
				die(_("object not found: %s"), reader->line);
			/* make sure that it is parsed as shallow */
			if (!parse_object(&oid))
				die(_("error in object: %s"), reader->line);
			if (unregister_shallow(&oid))
				die(_("no shallow found: %s"), reader->line);
			continue;
		}
		die(_("expected shallow/unshallow, got %s"), reader->line);
	}
 
	if (reader->status != PACKET_READ_FLUSH &&
	    reader->status != PACKET_READ_DELIM)
		die("error processing shallow info: %d", reader->status);
 
	setup_alternate_shallow(&shallow_lock, &alternate_shallow_file, NULL);
	args->deepen = 1;
}
 
enum fetch_state {
	FETCH_CHECK_LOCAL = 0,
	FETCH_SEND_REQUEST,
	FETCH_PROCESS_ACKS,
	FETCH_GET_PACK,
	FETCH_DONE,
};
 
static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
				    int fd[2],
				    const struct ref *orig_ref,
				    struct ref **sought, int nr_sought,
				    char **pack_lockfile)
{
	struct ref *ref = copy_ref_list(orig_ref);
	enum fetch_state state = FETCH_CHECK_LOCAL;
	struct oidset common = OIDSET_INIT;
	struct packet_reader reader;
	int in_vain = 0;
	int haves_to_send = INITIAL_FLUSH;
	packet_reader_init(&reader, fd[0], NULL, 0,
			   PACKET_READ_CHOMP_NEWLINE);
 
	while (state != FETCH_DONE) {
		switch (state) {
		case FETCH_CHECK_LOCAL:
			sort_ref_list(&ref, ref_compare_name);
			QSORT(sought, nr_sought, cmp_ref_by_name);
 
			/* v2 supports these by default */
			allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
			use_sideband = 2;
			if (args->depth > 0 || args->deepen_since || args->deepen_not)
				args->deepen = 1;
 
			if (marked)
				for_each_ref(clear_marks, NULL);
			marked = 1;
 
			for_each_ref(rev_list_insert_ref_oid, NULL);
			for_each_cached_alternate(insert_one_alternate_object);
 
			/* Filter 'ref' by 'sought' and those that aren't local */
			if (everything_local(args, &ref, sought, nr_sought))
				state = FETCH_DONE;
			else
				state = FETCH_SEND_REQUEST;
			break;
		case FETCH_SEND_REQUEST:
			if (send_fetch_request(fd[1], args, ref, &common,
					       &haves_to_send, &in_vain))
				state = FETCH_GET_PACK;
			else
				state = FETCH_PROCESS_ACKS;
			break;
		case FETCH_PROCESS_ACKS:
			/* Process ACKs/NAKs */
			switch (process_acks(&reader, &common)) {
			case 2:
				state = FETCH_GET_PACK;
				break;
			case 1:
				in_vain = 0;
				/* fallthrough */
			default:
				state = FETCH_SEND_REQUEST;
				break;
			}
			break;
		case FETCH_GET_PACK:
			/* Check for shallow-info section */
			if (process_section_header(&reader, "shallow-info", 1))
				receive_shallow_info(args, &reader);
 
			/* get the pack */
			process_section_header(&reader, "packfile", 0);
			if (get_pack(args, fd, pack_lockfile))
				die(_("git fetch-pack: fetch failed."));
 
			state = FETCH_DONE;
			break;
		case FETCH_DONE:
			continue;
		}
	}
 
	oidset_clear(&common);
	return ref;
}
 
static void fetch_pack_config(void)
{
	git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
	git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
	git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
	git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
	git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
 
	git_config(git_default_config, NULL);
}
 
static void fetch_pack_setup(void)
{
	static int did_setup;
	if (did_setup)
		return;
	fetch_pack_config();
	if (0 <= transfer_unpack_limit)
		unpack_limit = transfer_unpack_limit;
	else if (0 <= fetch_unpack_limit)
		unpack_limit = fetch_unpack_limit;
	did_setup = 1;
}
 
static int remove_duplicates_in_refs(struct ref **ref, int nr)
{
	struct string_list names = STRING_LIST_INIT_NODUP;
	int src, dst;
 
	for (src = dst = 0; src < nr; src++) {
		struct string_list_item *item;
		item = string_list_insert(&names, ref[src]->name);
		if (item->util)
			continue; /* already have it */
		item->util = ref[src];
		if (src != dst)
			ref[dst] = ref[src];
		dst++;
	}
	for (src = dst; src < nr; src++)
		ref[src] = NULL;
	string_list_clear(&names, 0);
	return dst;
}
 
static void update_shallow(struct fetch_pack_args *args,
			   struct ref **sought, int nr_sought,
			   struct shallow_info *si)
{
	struct oid_array ref = OID_ARRAY_INIT;
	int *status;
	int i;
 
	if (args->deepen && alternate_shallow_file) {
		if (*alternate_shallow_file == '\0') { /* --unshallow */
			unlink_or_warn(git_path_shallow());
			rollback_lock_file(&shallow_lock);
		} else
			commit_lock_file(&shallow_lock);
		return;
	}
 
	if (!si->shallow || !si->shallow->nr)
		return;
 
	if (args->cloning) {
		/*
		 * remote is shallow, but this is a clone, there are
		 * no objects in repo to worry about. Accept any
		 * shallow points that exist in the pack (iow in repo
		 * after get_pack() and reprepare_packed_git())
		 */
		struct oid_array extra = OID_ARRAY_INIT;
		struct object_id *oid = si->shallow->oid;
		for (i = 0; i < si->shallow->nr; i++)
			if (has_object_file(&oid[i]))
				oid_array_append(&extra, &oid[i]);
		if (extra.nr) {
			setup_alternate_shallow(&shallow_lock,
						&alternate_shallow_file,
						&extra);
			commit_lock_file(&shallow_lock);
		}
		oid_array_clear(&extra);
		return;
	}
 
	if (!si->nr_ours && !si->nr_theirs)
		return;
 
	remove_nonexistent_theirs_shallow(si);
	if (!si->nr_ours && !si->nr_theirs)
		return;
	for (i = 0; i < nr_sought; i++)
		oid_array_append(&ref, &sought[i]->old_oid);
	si->ref = &ref;
 
	if (args->update_shallow) {
		/*
		 * remote is also shallow, .git/shallow may be updated
		 * so all refs can be accepted. Make sure we only add
		 * shallow roots that are actually reachable from new
		 * refs.
		 */
		struct oid_array extra = OID_ARRAY_INIT;
		struct object_id *oid = si->shallow->oid;
		assign_shallow_commits_to_refs(si, NULL, NULL);
		if (!si->nr_ours && !si->nr_theirs) {
			oid_array_clear(&ref);
			return;
		}
		for (i = 0; i < si->nr_ours; i++)
			oid_array_append(&extra, &oid[si->ours[i]]);
		for (i = 0; i < si->nr_theirs; i++)
			oid_array_append(&extra, &oid[si->theirs[i]]);
		setup_alternate_shallow(&shallow_lock,
					&alternate_shallow_file,
					&extra);
		commit_lock_file(&shallow_lock);
		oid_array_clear(&extra);
		oid_array_clear(&ref);
		return;
	}
 
	/*
	 * remote is also shallow, check what ref is safe to update
	 * without updating .git/shallow
	 */
	status = xcalloc(nr_sought, sizeof(*status));
	assign_shallow_commits_to_refs(si, NULL, status);
	if (si->nr_ours || si->nr_theirs) {
		for (i = 0; i < nr_sought; i++)
			if (status[i])
				sought[i]->status = REF_STATUS_REJECT_SHALLOW;
	}
	free(status);
	oid_array_clear(&ref);
}
 
struct ref *fetch_pack(struct fetch_pack_args *args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		       const char *dest,
		       struct ref **sought, int nr_sought,
		       struct oid_array *shallow,
		       char **pack_lockfile,
		       enum protocol_version version)
{
	struct ref *ref_cpy;
	struct shallow_info si;
 
	fetch_pack_setup();
	if (nr_sought)
		nr_sought = remove_duplicates_in_refs(sought, nr_sought);
 
	if (!ref) {
		packet_flush(fd[1]);
		die(_("no matching remote head"));
	}
	prepare_shallow_info(&si, shallow);
	if (version == protocol_v2)
		ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
					   pack_lockfile);
	else
		ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
					&si, pack_lockfile);
	reprepare_packed_git(the_repository);
	update_shallow(args, sought, nr_sought, &si);
	clear_shallow_info(&si);
	return ref_cpy;
}
 
int report_unmatched_refs(struct ref **sought, int nr_sought)
{
	int i, ret = 0;
 
	for (i = 0; i < nr_sought; i++) {
		if (!sought[i])
			continue;
		switch (sought[i]->match_status) {
		case REF_MATCHED:
			continue;
		case REF_NOT_MATCHED:
			error(_("no such remote ref %s"), sought[i]->name);
			break;
		case REF_UNADVERTISED_NOT_ALLOWED:
			error(_("Server does not allow request for unadvertised object %s"),
			      sought[i]->name);
			break;
		}
		ret = 1;
	}
	return ret;
}