Source

git / commit.c

Full commit
   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
#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "pkt-line.h"
#include "utf8.h"
#include "diff.h"
#include "revision.h"
#include "notes.h"

int save_commit_buffer = 1;

const char *commit_type = "commit";

static struct commit *check_commit(struct object *obj,
				   const unsigned char *sha1,
				   int quiet)
{
	if (obj->type != OBJ_COMMIT) {
		if (!quiet)
			error("Object %s is a %s, not a commit",
			      sha1_to_hex(sha1), typename(obj->type));
		return NULL;
	}
	return (struct commit *) obj;
}

struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
					      int quiet)
{
	struct object *obj = deref_tag(parse_object(sha1), NULL, 0);

	if (!obj)
		return NULL;
	return check_commit(obj, sha1, quiet);
}

struct commit *lookup_commit_reference(const unsigned char *sha1)
{
	return lookup_commit_reference_gently(sha1, 0);
}

struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
{
	struct commit *c = lookup_commit_reference(sha1);
	if (!c)
		die(_("could not parse %s"), ref_name);
	if (hashcmp(sha1, c->object.sha1)) {
		warning(_("%s %s is not a commit!"),
			ref_name, sha1_to_hex(sha1));
	}
	return c;
}

struct commit *lookup_commit(const unsigned char *sha1)
{
	struct object *obj = lookup_object(sha1);
	if (!obj)
		return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
	if (!obj->type)
		obj->type = OBJ_COMMIT;
	return check_commit(obj, sha1, 0);
}

struct commit *lookup_commit_reference_by_name(const char *name)
{
	unsigned char sha1[20];
	struct commit *commit;

	if (get_sha1(name, sha1))
		return NULL;
	commit = lookup_commit_reference(sha1);
	if (!commit || parse_commit(commit))
		return NULL;
	return commit;
}

static unsigned long parse_commit_date(const char *buf, const char *tail)
{
	const char *dateptr;

	if (buf + 6 >= tail)
		return 0;
	if (memcmp(buf, "author", 6))
		return 0;
	while (buf < tail && *buf++ != '\n')
		/* nada */;
	if (buf + 9 >= tail)
		return 0;
	if (memcmp(buf, "committer", 9))
		return 0;
	while (buf < tail && *buf++ != '>')
		/* nada */;
	if (buf >= tail)
		return 0;
	dateptr = buf;
	while (buf < tail && *buf++ != '\n')
		/* nada */;
	if (buf >= tail)
		return 0;
	/* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
	return strtoul(dateptr, NULL, 10);
}

static struct commit_graft **commit_graft;
static int commit_graft_alloc, commit_graft_nr;

static int commit_graft_pos(const unsigned char *sha1)
{
	int lo, hi;
	lo = 0;
	hi = commit_graft_nr;
	while (lo < hi) {
		int mi = (lo + hi) / 2;
		struct commit_graft *graft = commit_graft[mi];
		int cmp = hashcmp(sha1, graft->sha1);
		if (!cmp)
			return mi;
		if (cmp < 0)
			hi = mi;
		else
			lo = mi + 1;
	}
	return -lo - 1;
}

int register_commit_graft(struct commit_graft *graft, int ignore_dups)
{
	int pos = commit_graft_pos(graft->sha1);

	if (0 <= pos) {
		if (ignore_dups)
			free(graft);
		else {
			free(commit_graft[pos]);
			commit_graft[pos] = graft;
		}
		return 1;
	}
	pos = -pos - 1;
	if (commit_graft_alloc <= ++commit_graft_nr) {
		commit_graft_alloc = alloc_nr(commit_graft_alloc);
		commit_graft = xrealloc(commit_graft,
					sizeof(*commit_graft) *
					commit_graft_alloc);
	}
	if (pos < commit_graft_nr)
		memmove(commit_graft + pos + 1,
			commit_graft + pos,
			(commit_graft_nr - pos - 1) *
			sizeof(*commit_graft));
	commit_graft[pos] = graft;
	return 0;
}

struct commit_graft *read_graft_line(char *buf, int len)
{
	/* The format is just "Commit Parent1 Parent2 ...\n" */
	int i;
	struct commit_graft *graft = NULL;

	while (len && isspace(buf[len-1]))
		buf[--len] = '\0';
	if (buf[0] == '#' || buf[0] == '\0')
		return NULL;
	if ((len + 1) % 41)
		goto bad_graft_data;
	i = (len + 1) / 41 - 1;
	graft = xmalloc(sizeof(*graft) + 20 * i);
	graft->nr_parent = i;
	if (get_sha1_hex(buf, graft->sha1))
		goto bad_graft_data;
	for (i = 40; i < len; i += 41) {
		if (buf[i] != ' ')
			goto bad_graft_data;
		if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
			goto bad_graft_data;
	}
	return graft;

bad_graft_data:
	error("bad graft data: %s", buf);
	free(graft);
	return NULL;
}

static int read_graft_file(const char *graft_file)
{
	FILE *fp = fopen(graft_file, "r");
	char buf[1024];
	if (!fp)
		return -1;
	while (fgets(buf, sizeof(buf), fp)) {
		/* The format is just "Commit Parent1 Parent2 ...\n" */
		int len = strlen(buf);
		struct commit_graft *graft = read_graft_line(buf, len);
		if (!graft)
			continue;
		if (register_commit_graft(graft, 1))
			error("duplicate graft data: %s", buf);
	}
	fclose(fp);
	return 0;
}

static void prepare_commit_graft(void)
{
	static int commit_graft_prepared;
	char *graft_file;

	if (commit_graft_prepared)
		return;
	graft_file = get_graft_file();
	read_graft_file(graft_file);
	/* make sure shallows are read */
	is_repository_shallow();
	commit_graft_prepared = 1;
}

struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
{
	int pos;
	prepare_commit_graft();
	pos = commit_graft_pos(sha1);
	if (pos < 0)
		return NULL;
	return commit_graft[pos];
}

int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
{
	int i, ret;
	for (i = ret = 0; i < commit_graft_nr && !ret; i++)
		ret = fn(commit_graft[i], cb_data);
	return ret;
}

int unregister_shallow(const unsigned char *sha1)
{
	int pos = commit_graft_pos(sha1);
	if (pos < 0)
		return -1;
	if (pos + 1 < commit_graft_nr)
		memmove(commit_graft + pos, commit_graft + pos + 1,
				sizeof(struct commit_graft *)
				* (commit_graft_nr - pos - 1));
	commit_graft_nr--;
	return 0;
}

int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
{
	const char *tail = buffer;
	const char *bufptr = buffer;
	unsigned char parent[20];
	struct commit_list **pptr;
	struct commit_graft *graft;

	if (item->object.parsed)
		return 0;
	item->object.parsed = 1;
	tail += size;
	if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
		return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
	if (get_sha1_hex(bufptr + 5, parent) < 0)
		return error("bad tree pointer in commit %s",
			     sha1_to_hex(item->object.sha1));
	item->tree = lookup_tree(parent);
	bufptr += 46; /* "tree " + "hex sha1" + "\n" */
	pptr = &item->parents;

	graft = lookup_commit_graft(item->object.sha1);
	while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
		struct commit *new_parent;

		if (tail <= bufptr + 48 ||
		    get_sha1_hex(bufptr + 7, parent) ||
		    bufptr[47] != '\n')
			return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
		bufptr += 48;
		/*
		 * The clone is shallow if nr_parent < 0, and we must
		 * not traverse its real parents even when we unhide them.
		 */
		if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
			continue;
		new_parent = lookup_commit(parent);
		if (new_parent)
			pptr = &commit_list_insert(new_parent, pptr)->next;
	}
	if (graft) {
		int i;
		struct commit *new_parent;
		for (i = 0; i < graft->nr_parent; i++) {
			new_parent = lookup_commit(graft->parent[i]);
			if (!new_parent)
				continue;
			pptr = &commit_list_insert(new_parent, pptr)->next;
		}
	}
	item->date = parse_commit_date(bufptr, tail);

	return 0;
}

int parse_commit(struct commit *item)
{
	enum object_type type;
	void *buffer;
	unsigned long size;
	int ret;

	if (!item)
		return -1;
	if (item->object.parsed)
		return 0;
	buffer = read_sha1_file(item->object.sha1, &type, &size);
	if (!buffer)
		return error("Could not read %s",
			     sha1_to_hex(item->object.sha1));
	if (type != OBJ_COMMIT) {
		free(buffer);
		return error("Object %s not a commit",
			     sha1_to_hex(item->object.sha1));
	}
	ret = parse_commit_buffer(item, buffer, size);
	if (save_commit_buffer && !ret) {
		item->buffer = buffer;
		return 0;
	}
	free(buffer);
	return ret;
}

int find_commit_subject(const char *commit_buffer, const char **subject)
{
	const char *eol;
	const char *p = commit_buffer;

	while (*p && (*p != '\n' || p[1] != '\n'))
		p++;
	if (*p) {
		p += 2;
		for (eol = p; *eol && *eol != '\n'; eol++)
			; /* do nothing */
	} else
		eol = p;

	*subject = p;

	return eol - p;
}

struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
{
	struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
	new_list->item = item;
	new_list->next = *list_p;
	*list_p = new_list;
	return new_list;
}

unsigned commit_list_count(const struct commit_list *l)
{
	unsigned c = 0;
	for (; l; l = l->next )
		c++;
	return c;
}

void free_commit_list(struct commit_list *list)
{
	while (list) {
		struct commit_list *temp = list;
		list = temp->next;
		free(temp);
	}
}

struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
{
	struct commit_list **pp = list;
	struct commit_list *p;
	while ((p = *pp) != NULL) {
		if (p->item->date < item->date) {
			break;
		}
		pp = &p->next;
	}
	return commit_list_insert(item, pp);
}


void commit_list_sort_by_date(struct commit_list **list)
{
	struct commit_list *ret = NULL;
	while (*list) {
		commit_list_insert_by_date((*list)->item, &ret);
		*list = (*list)->next;
	}
	*list = ret;
}

struct commit *pop_most_recent_commit(struct commit_list **list,
				      unsigned int mark)
{
	struct commit *ret = (*list)->item;
	struct commit_list *parents = ret->parents;
	struct commit_list *old = *list;

	*list = (*list)->next;
	free(old);

	while (parents) {
		struct commit *commit = parents->item;
		if (!parse_commit(commit) && !(commit->object.flags & mark)) {
			commit->object.flags |= mark;
			commit_list_insert_by_date(commit, list);
		}
		parents = parents->next;
	}
	return ret;
}

static void clear_commit_marks_1(struct commit_list **plist,
				 struct commit *commit, unsigned int mark)
{
	while (commit) {
		struct commit_list *parents;

		if (!(mark & commit->object.flags))
			return;

		commit->object.flags &= ~mark;

		parents = commit->parents;
		if (!parents)
			return;

		while ((parents = parents->next))
			commit_list_insert(parents->item, plist);

		commit = commit->parents->item;
	}
}

void clear_commit_marks(struct commit *commit, unsigned int mark)
{
	struct commit_list *list = NULL;
	commit_list_insert(commit, &list);
	while (list)
		clear_commit_marks_1(&list, pop_commit(&list), mark);
}

void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
{
	struct object *object;
	struct commit *commit;
	unsigned int i;

	for (i = 0; i < a->nr; i++) {
		object = a->objects[i].item;
		commit = lookup_commit_reference_gently(object->sha1, 1);
		if (commit)
			clear_commit_marks(commit, mark);
	}
}

struct commit *pop_commit(struct commit_list **stack)
{
	struct commit_list *top = *stack;
	struct commit *item = top ? top->item : NULL;

	if (top) {
		*stack = top->next;
		free(top);
	}
	return item;
}

/*
 * Performs an in-place topological sort on the list supplied.
 */
void sort_in_topological_order(struct commit_list ** list, int lifo)
{
	struct commit_list *next, *orig = *list;
	struct commit_list *work, **insert;
	struct commit_list **pptr;

	if (!orig)
		return;
	*list = NULL;

	/* Mark them and clear the indegree */
	for (next = orig; next; next = next->next) {
		struct commit *commit = next->item;
		commit->indegree = 1;
	}

	/* update the indegree */
	for (next = orig; next; next = next->next) {
		struct commit_list * parents = next->item->parents;
		while (parents) {
			struct commit *parent = parents->item;

			if (parent->indegree)
				parent->indegree++;
			parents = parents->next;
		}
	}

	/*
	 * find the tips
	 *
	 * tips are nodes not reachable from any other node in the list
	 *
	 * the tips serve as a starting set for the work queue.
	 */
	work = NULL;
	insert = &work;
	for (next = orig; next; next = next->next) {
		struct commit *commit = next->item;

		if (commit->indegree == 1)
			insert = &commit_list_insert(commit, insert)->next;
	}

	/* process the list in topological order */
	if (!lifo)
		commit_list_sort_by_date(&work);

	pptr = list;
	*list = NULL;
	while (work) {
		struct commit *commit;
		struct commit_list *parents, *work_item;

		work_item = work;
		work = work_item->next;
		work_item->next = NULL;

		commit = work_item->item;
		for (parents = commit->parents; parents ; parents = parents->next) {
			struct commit *parent = parents->item;

			if (!parent->indegree)
				continue;

			/*
			 * parents are only enqueued for emission
			 * when all their children have been emitted thereby
			 * guaranteeing topological order.
			 */
			if (--parent->indegree == 1) {
				if (!lifo)
					commit_list_insert_by_date(parent, &work);
				else
					commit_list_insert(parent, &work);
			}
		}
		/*
		 * work_item is a commit all of whose children
		 * have already been emitted. we can emit it now.
		 */
		commit->indegree = 0;
		*pptr = work_item;
		pptr = &work_item->next;
	}
}

/* merge-base stuff */

/* bits #0..15 in revision.h */
#define PARENT1		(1u<<16)
#define PARENT2		(1u<<17)
#define STALE		(1u<<18)
#define RESULT		(1u<<19)

static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);

static struct commit *interesting(struct commit_list *list)
{
	while (list) {
		struct commit *commit = list->item;
		list = list->next;
		if (commit->object.flags & STALE)
			continue;
		return commit;
	}
	return NULL;
}

static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
{
	struct commit_list *list = NULL;
	struct commit_list *result = NULL;
	int i;

	for (i = 0; i < n; i++) {
		if (one == twos[i])
			/*
			 * We do not mark this even with RESULT so we do not
			 * have to clean it up.
			 */
			return commit_list_insert(one, &result);
	}

	if (parse_commit(one))
		return NULL;
	for (i = 0; i < n; i++) {
		if (parse_commit(twos[i]))
			return NULL;
	}

	one->object.flags |= PARENT1;
	commit_list_insert_by_date(one, &list);
	for (i = 0; i < n; i++) {
		twos[i]->object.flags |= PARENT2;
		commit_list_insert_by_date(twos[i], &list);
	}

	while (interesting(list)) {
		struct commit *commit;
		struct commit_list *parents;
		struct commit_list *next;
		int flags;

		commit = list->item;
		next = list->next;
		free(list);
		list = next;

		flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
		if (flags == (PARENT1 | PARENT2)) {
			if (!(commit->object.flags & RESULT)) {
				commit->object.flags |= RESULT;
				commit_list_insert_by_date(commit, &result);
			}
			/* Mark parents of a found merge stale */
			flags |= STALE;
		}
		parents = commit->parents;
		while (parents) {
			struct commit *p = parents->item;
			parents = parents->next;
			if ((p->object.flags & flags) == flags)
				continue;
			if (parse_commit(p))
				return NULL;
			p->object.flags |= flags;
			commit_list_insert_by_date(p, &list);
		}
	}

	/* Clean up the result to remove stale ones */
	free_commit_list(list);
	list = result; result = NULL;
	while (list) {
		struct commit_list *next = list->next;
		if (!(list->item->object.flags & STALE))
			commit_list_insert_by_date(list->item, &result);
		free(list);
		list = next;
	}
	return result;
}

struct commit_list *get_octopus_merge_bases(struct commit_list *in)
{
	struct commit_list *i, *j, *k, *ret = NULL;
	struct commit_list **pptr = &ret;

	for (i = in; i; i = i->next) {
		if (!ret)
			pptr = &commit_list_insert(i->item, pptr)->next;
		else {
			struct commit_list *new = NULL, *end = NULL;

			for (j = ret; j; j = j->next) {
				struct commit_list *bases;
				bases = get_merge_bases(i->item, j->item, 1);
				if (!new)
					new = bases;
				else
					end->next = bases;
				for (k = bases; k; k = k->next)
					end = k;
			}
			ret = new;
		}
	}
	return ret;
}

struct commit_list *get_merge_bases_many(struct commit *one,
					 int n,
					 struct commit **twos,
					 int cleanup)
{
	struct commit_list *list;
	struct commit **rslt;
	struct commit_list *result;
	int cnt, i, j;

	result = merge_bases_many(one, n, twos);
	for (i = 0; i < n; i++) {
		if (one == twos[i])
			return result;
	}
	if (!result || !result->next) {
		if (cleanup) {
			clear_commit_marks(one, all_flags);
			for (i = 0; i < n; i++)
				clear_commit_marks(twos[i], all_flags);
		}
		return result;
	}

	/* There are more than one */
	cnt = 0;
	list = result;
	while (list) {
		list = list->next;
		cnt++;
	}
	rslt = xcalloc(cnt, sizeof(*rslt));
	for (list = result, i = 0; list; list = list->next)
		rslt[i++] = list->item;
	free_commit_list(result);

	clear_commit_marks(one, all_flags);
	for (i = 0; i < n; i++)
		clear_commit_marks(twos[i], all_flags);
	for (i = 0; i < cnt - 1; i++) {
		for (j = i+1; j < cnt; j++) {
			if (!rslt[i] || !rslt[j])
				continue;
			result = merge_bases_many(rslt[i], 1, &rslt[j]);
			clear_commit_marks(rslt[i], all_flags);
			clear_commit_marks(rslt[j], all_flags);
			for (list = result; list; list = list->next) {
				if (rslt[i] == list->item)
					rslt[i] = NULL;
				if (rslt[j] == list->item)
					rslt[j] = NULL;
			}
		}
	}

	/* Surviving ones in rslt[] are the independent results */
	result = NULL;
	for (i = 0; i < cnt; i++) {
		if (rslt[i])
			commit_list_insert_by_date(rslt[i], &result);
	}
	free(rslt);
	return result;
}

struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
				    int cleanup)
{
	return get_merge_bases_many(one, 1, &two, cleanup);
}

int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
{
	if (!with_commit)
		return 1;
	while (with_commit) {
		struct commit *other;

		other = with_commit->item;
		with_commit = with_commit->next;
		if (in_merge_bases(other, &commit, 1))
			return 1;
	}
	return 0;
}

int in_merge_bases(struct commit *commit, struct commit **reference, int num)
{
	struct commit_list *bases, *b;
	int ret = 0;

	if (num == 1)
		bases = get_merge_bases(commit, *reference, 1);
	else
		die("not yet");
	for (b = bases; b; b = b->next) {
		if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
			ret = 1;
			break;
		}
	}

	free_commit_list(bases);
	return ret;
}

struct commit_list *reduce_heads(struct commit_list *heads)
{
	struct commit_list *p;
	struct commit_list *result = NULL, **tail = &result;
	struct commit **other;
	size_t num_head, num_other;

	if (!heads)
		return NULL;

	/* Avoid unnecessary reallocations */
	for (p = heads, num_head = 0; p; p = p->next)
		num_head++;
	other = xcalloc(sizeof(*other), num_head);

	/* For each commit, see if it can be reached by others */
	for (p = heads; p; p = p->next) {
		struct commit_list *q, *base;

		/* Do we already have this in the result? */
		for (q = result; q; q = q->next)
			if (p->item == q->item)
				break;
		if (q)
			continue;

		num_other = 0;
		for (q = heads; q; q = q->next) {
			if (p->item == q->item)
				continue;
			other[num_other++] = q->item;
		}
		if (num_other)
			base = get_merge_bases_many(p->item, num_other, other, 1);
		else
			base = NULL;
		/*
		 * If p->item does not have anything common with other
		 * commits, there won't be any merge base.  If it is
		 * reachable from some of the others, p->item will be
		 * the merge base.  If its history is connected with
		 * others, but p->item is not reachable by others, we
		 * will get something other than p->item back.
		 */
		if (!base || (base->item != p->item))
			tail = &(commit_list_insert(p->item, tail)->next);
		free_commit_list(base);
	}
	free(other);
	return result;
}

static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
{
	struct merge_remote_desc *desc;
	struct commit_extra_header *mergetag;
	char *buf;
	unsigned long size, len;
	enum object_type type;

	desc = merge_remote_util(parent);
	if (!desc || !desc->obj)
		return;
	buf = read_sha1_file(desc->obj->sha1, &type, &size);
	if (!buf || type != OBJ_TAG)
		goto free_return;
	len = parse_signature(buf, size);
	if (size == len)
		goto free_return;
	/*
	 * We could verify this signature and either omit the tag when
	 * it does not validate, but the integrator may not have the
	 * public key of the signer of the tag he is merging, while a
	 * later auditor may have it while auditing, so let's not run
	 * verify-signed-buffer here for now...
	 *
	 * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
	 *	warn("warning: signed tag unverified.");
	 */
	mergetag = xcalloc(1, sizeof(*mergetag));
	mergetag->key = xstrdup("mergetag");
	mergetag->value = buf;
	mergetag->len = size;

	**tail = mergetag;
	*tail = &mergetag->next;
	return;

free_return:
	free(buf);
}

void append_merge_tag_headers(struct commit_list *parents,
			      struct commit_extra_header ***tail)
{
	while (parents) {
		struct commit *parent = parents->item;
		handle_signed_tag(parent, tail);
		parents = parents->next;
	}
}

static void add_extra_header(struct strbuf *buffer,
			     struct commit_extra_header *extra)
{
	strbuf_addstr(buffer, extra->key);
	if (extra->len)
		strbuf_add_lines(buffer, " ", extra->value, extra->len);
	else
		strbuf_addch(buffer, '\n');
}

struct commit_extra_header *read_commit_extra_headers(struct commit *commit)
{
	struct commit_extra_header *extra = NULL;
	unsigned long size;
	enum object_type type;
	char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
	if (buffer && type == OBJ_COMMIT)
		extra = read_commit_extra_header_lines(buffer, size);
	free(buffer);
	return extra;
}

static inline int standard_header_field(const char *field, size_t len)
{
	return ((len == 4 && !memcmp(field, "tree ", 5)) ||
		(len == 6 && !memcmp(field, "parent ", 7)) ||
		(len == 6 && !memcmp(field, "author ", 7)) ||
		(len == 9 && !memcmp(field, "committer ", 10)) ||
		(len == 8 && !memcmp(field, "encoding ", 9)));
}

struct commit_extra_header *read_commit_extra_header_lines(const char *buffer, size_t size)
{
	struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
	const char *line, *next, *eof, *eob;
	struct strbuf buf = STRBUF_INIT;

	for (line = buffer, eob = line + size;
	     line < eob && *line != '\n';
	     line = next) {
		next = memchr(line, '\n', eob - line);
		next = next ? next + 1 : eob;
		if (*line == ' ') {
			/* continuation */
			if (it)
				strbuf_add(&buf, line + 1, next - (line + 1));
			continue;
		}
		if (it)
			it->value = strbuf_detach(&buf, &it->len);
		strbuf_reset(&buf);
		it = NULL;

		eof = strchr(line, ' ');
		if (next <= eof)
			eof = next;

		if (standard_header_field(line, eof - line))
			continue;

		it = xcalloc(1, sizeof(*it));
		it->key = xmemdupz(line, eof-line);
		*tail = it;
		tail = &it->next;
		if (eof + 1 < next)
			strbuf_add(&buf, eof + 1, next - (eof + 1));
	}
	if (it)
		it->value = strbuf_detach(&buf, &it->len);
	return extra;
}

void free_commit_extra_headers(struct commit_extra_header *extra)
{
	while (extra) {
		struct commit_extra_header *next = extra->next;
		free(extra->key);
		free(extra->value);
		free(extra);
		extra = next;
	}
}

int commit_tree(const struct strbuf *msg, unsigned char *tree,
		struct commit_list *parents, unsigned char *ret,
		const char *author)
{
	struct commit_extra_header *extra = NULL, **tail = &extra;
	int result;

	append_merge_tag_headers(parents, &tail);
	result = commit_tree_extended(msg, tree, parents, ret, author, extra);
	free_commit_extra_headers(extra);
	return result;
}

static const char commit_utf8_warn[] =
"Warning: commit message does not conform to UTF-8.\n"
"You may want to amend it after fixing the message, or set the config\n"
"variable i18n.commitencoding to the encoding your project uses.\n";

int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
			 struct commit_list *parents, unsigned char *ret,
			 const char *author, struct commit_extra_header *extra)
{
	int result;
	int encoding_is_utf8;
	struct strbuf buffer;

	assert_sha1_type(tree, OBJ_TREE);

	if (memchr(msg->buf, '\0', msg->len))
		return error("a NUL byte in commit log message not allowed.");

	/* Not having i18n.commitencoding is the same as having utf-8 */
	encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);

	strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
	strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));

	/*
	 * NOTE! This ordering means that the same exact tree merged with a
	 * different order of parents will be a _different_ changeset even
	 * if everything else stays the same.
	 */
	while (parents) {
		struct commit_list *next = parents->next;
		struct commit *parent = parents->item;

		strbuf_addf(&buffer, "parent %s\n",
			    sha1_to_hex(parent->object.sha1));
		free(parents);
		parents = next;
	}

	/* Person/date information */
	if (!author)
		author = git_author_info(IDENT_ERROR_ON_NO_NAME);
	strbuf_addf(&buffer, "author %s\n", author);
	strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_ERROR_ON_NO_NAME));
	if (!encoding_is_utf8)
		strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);

	while (extra) {
		add_extra_header(&buffer, extra);
		extra = extra->next;
	}
	strbuf_addch(&buffer, '\n');

	/* And add the comment */
	strbuf_addbuf(&buffer, msg);

	/* And check the encoding */
	if (encoding_is_utf8 && !is_utf8(buffer.buf))
		fprintf(stderr, commit_utf8_warn);

	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
	strbuf_release(&buffer);
	return result;
}

struct commit *get_merge_parent(const char *name)
{
	struct object *obj;
	struct commit *commit;
	unsigned char sha1[20];
	if (get_sha1(name, sha1))
		return NULL;
	obj = parse_object(sha1);
	commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
	if (commit && !commit->util) {
		struct merge_remote_desc *desc;
		desc = xmalloc(sizeof(*desc));
		desc->obj = obj;
		desc->name = strdup(name);
		commit->util = desc;
	}
	return commit;
}