summaryrefslogtreecommitdiff
path: root/builtin/clone.c
blob: caae43e7a390d8666cda259e995c14079103d20d (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
/*
 * Builtin "git clone"
 *
 * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>,
 *		 2008 Daniel Barkalow <barkalow@iabervon.org>
 * Based on git-commit.sh by Junio C Hamano and Linus Torvalds
 *
 * Clone a repository into a different directory that does not yet exist.
 */

#include "builtin.h"
#include "lockfile.h"
#include "parse-options.h"
#include "fetch-pack.h"
#include "refs.h"
#include "tree.h"
#include "tree-walk.h"
#include "unpack-trees.h"
#include "transport.h"
#include "strbuf.h"
#include "dir.h"
#include "sigchain.h"
#include "branch.h"
#include "remote.h"
#include "run-command.h"
#include "connected.h"

/*
 * Overall FIXMEs:
 *  - respect DB_ENVIRONMENT for .git/objects.
 *
 * Implementation notes:
 *  - dropping use-separate-remote and no-separate-remote compatibility
 *
 */
static const char * const builtin_clone_usage[] = {
	N_("git clone [<options>] [--] <repo> [<dir>]"),
	NULL
};

static int option_no_checkout, option_bare, option_mirror, option_single_branch = -1;
static int option_local = -1, option_no_hardlinks, option_shared, option_recursive;
static char *option_template, *option_depth;
static char *option_origin = NULL;
static char *option_branch = NULL;
static const char *real_git_dir;
static char *option_upload_pack = "git-upload-pack";
static int option_verbosity;
static int option_progress = -1;
static struct string_list option_config;
static struct string_list option_reference;
static int option_dissociate;

static struct option builtin_clone_options[] = {
	OPT__VERBOSITY(&option_verbosity),
	OPT_BOOL(0, "progress", &option_progress,
		 N_("force progress reporting")),
	OPT_BOOL('n', "no-checkout", &option_no_checkout,
		 N_("don't create a checkout")),
	OPT_BOOL(0, "bare", &option_bare, N_("create a bare repository")),
	OPT_HIDDEN_BOOL(0, "naked", &option_bare,
			N_("create a bare repository")),
	OPT_BOOL(0, "mirror", &option_mirror,
		 N_("create a mirror repository (implies bare)")),
	OPT_BOOL('l', "local", &option_local,
		N_("to clone from a local repository")),
	OPT_BOOL(0, "no-hardlinks", &option_no_hardlinks,
		    N_("don't use local hardlinks, always copy")),
	OPT_BOOL('s', "shared", &option_shared,
		    N_("setup as shared repository")),
	OPT_BOOL(0, "recursive", &option_recursive,
		    N_("initialize submodules in the clone")),
	OPT_BOOL(0, "recurse-submodules", &option_recursive,
		    N_("initialize submodules in the clone")),
	OPT_STRING(0, "template", &option_template, N_("template-directory"),
		   N_("directory from which templates will be used")),
	OPT_STRING_LIST(0, "reference", &option_reference, N_("repo"),
			N_("reference repository")),
	OPT_BOOL(0, "dissociate", &option_dissociate,
		 N_("use --reference only while cloning")),
	OPT_STRING('o', "origin", &option_origin, N_("name"),
		   N_("use <name> instead of 'origin' to track upstream")),
	OPT_STRING('b', "branch", &option_branch, N_("branch"),
		   N_("checkout <branch> instead of the remote's HEAD")),
	OPT_STRING('u', "upload-pack", &option_upload_pack, N_("path"),
		   N_("path to git-upload-pack on the remote")),
	OPT_STRING(0, "depth", &option_depth, N_("depth"),
		    N_("create a shallow clone of that depth")),
	OPT_BOOL(0, "single-branch", &option_single_branch,
		    N_("clone only one branch, HEAD or --branch")),
	OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
		   N_("separate git dir from working tree")),
	OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),
			N_("set config inside the new repository")),
	OPT_END()
};

static const char *argv_submodule[] = {
	"submodule", "update", "--init", "--recursive", NULL
};

static const char *get_repo_path_1(struct strbuf *path, int *is_bundle)
{
	static char *suffix[] = { "/.git", "", ".git/.git", ".git" };
	static char *bundle_suffix[] = { ".bundle", "" };
	size_t baselen = path->len;
	struct stat st;
	int i;

	for (i = 0; i < ARRAY_SIZE(suffix); i++) {
		strbuf_setlen(path, baselen);
		strbuf_addstr(path, suffix[i]);
		if (stat(path->buf, &st))
			continue;
		if (S_ISDIR(st.st_mode) && is_git_directory(path->buf)) {
			*is_bundle = 0;
			return path->buf;
		} else if (S_ISREG(st.st_mode) && st.st_size > 8) {
			/* Is it a "gitfile"? */
			char signature[8];
			const char *dst;
			int len, fd = open(path->buf, O_RDONLY);
			if (fd < 0)
				continue;
			len = read_in_full(fd, signature, 8);
			close(fd);
			if (len != 8 || strncmp(signature, "gitdir: ", 8))
				continue;
			dst = read_gitfile(path->buf);
			if (dst) {
				*is_bundle = 0;
				return dst;
			}
		}
	}

	for (i = 0; i < ARRAY_SIZE(bundle_suffix); i++) {
		strbuf_setlen(path, baselen);
		strbuf_addstr(path, bundle_suffix[i]);
		if (!stat(path->buf, &st) && S_ISREG(st.st_mode)) {
			*is_bundle = 1;
			return path->buf;
		}
	}

	return NULL;
}

static char *get_repo_path(const char *repo, int *is_bundle)
{
	struct strbuf path = STRBUF_INIT;
	const char *raw;
	char *canon;

	strbuf_addstr(&path, repo);
	raw = get_repo_path_1(&path, is_bundle);
	canon = raw ? xstrdup(absolute_path(raw)) : NULL;
	strbuf_release(&path);
	return canon;
}

static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
{
	const char *end = repo + strlen(repo), *start, *ptr;
	size_t len;
	char *dir;

	/*
	 * Skip scheme.
	 */
	start = strstr(repo, "://");
	if (start == NULL)
		start = repo;
	else
		start += 3;

	/*
	 * Skip authentication data. The stripping does happen
	 * greedily, such that we strip up to the last '@' inside
	 * the host part.
	 */
	for (ptr = start; ptr < end && !is_dir_sep(*ptr); ptr++) {
		if (*ptr == '@')
			start = ptr + 1;
	}

	/*
	 * Strip trailing spaces, slashes and /.git
	 */
	while (start < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
		end--;
	if (end - start > 5 && is_dir_sep(end[-5]) &&
	    !strncmp(end - 4, ".git", 4)) {
		end -= 5;
		while (start < end && is_dir_sep(end[-1]))
			end--;
	}

	/*
	 * Strip trailing port number if we've got only a
	 * hostname (that is, there is no dir separator but a
	 * colon). This check is required such that we do not
	 * strip URI's like '/foo/bar:2222.git', which should
	 * result in a dir '2222' being guessed due to backwards
	 * compatibility.
	 */
	if (memchr(start, '/', end - start) == NULL
	    && memchr(start, ':', end - start) != NULL) {
		ptr = end;
		while (start < ptr && isdigit(ptr[-1]) && ptr[-1] != ':')
			ptr--;
		if (start < ptr && ptr[-1] == ':')
			end = ptr - 1;
	}

	/*
	 * Find last component. To remain backwards compatible we
	 * also regard colons as path separators, such that
	 * cloning a repository 'foo:bar.git' would result in a
	 * directory 'bar' being guessed.
	 */
	ptr = end;
	while (start < ptr && !is_dir_sep(ptr[-1]) && ptr[-1] != ':')
		ptr--;
	start = ptr;

	/*
	 * Strip .{bundle,git}.
	 */
	len = end - start;
	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");

	if (!len || (len == 1 && *start == '/'))
	    die("No directory name could be guessed.\n"
		"Please specify a directory on the command line");

	if (is_bare)
		dir = xstrfmt("%.*s.git", (int)len, start);
	else
		dir = xstrndup(start, len);
	/*
	 * Replace sequences of 'control' characters and whitespace
	 * with one ascii space, remove leading and trailing spaces.
	 */
	if (*dir) {
		char *out = dir;
		int prev_space = 1 /* strip leading whitespace */;
		for (end = dir; *end; ++end) {
			char ch = *end;
			if ((unsigned char)ch < '\x20')
				ch = '\x20';
			if (isspace(ch)) {
				if (prev_space)
					continue;
				prev_space = 1;
			} else
				prev_space = 0;
			*out++ = ch;
		}
		*out = '\0';
		if (out > dir && prev_space)
			out[-1] = '\0';
	}
	return dir;
}

static void strip_trailing_slashes(char *dir)
{
	char *end = dir + strlen(dir);

	while (dir < end - 1 && is_dir_sep(end[-1]))
		end--;
	*end = '\0';
}

static int add_one_reference(struct string_list_item *item, void *cb_data)
{
	char *ref_git;
	const char *repo;
	struct strbuf alternate = STRBUF_INIT;

	/* Beware: read_gitfile(), real_path() and mkpath() return static buffer */
	ref_git = xstrdup(real_path(item->string));

	repo = read_gitfile(ref_git);
	if (!repo)
		repo = read_gitfile(mkpath("%s/.git", ref_git));
	if (repo) {
		free(ref_git);
		ref_git = xstrdup(repo);
	}

	if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
		char *ref_git_git = mkpathdup("%s/.git", ref_git);
		free(ref_git);
		ref_git = ref_git_git;
	} else if (!is_directory(mkpath("%s/objects", ref_git))) {
		struct strbuf sb = STRBUF_INIT;
		if (get_common_dir(&sb, ref_git))
			die(_("reference repository '%s' as a linked checkout is not supported yet."),
			    item->string);
		die(_("reference repository '%s' is not a local repository."),
		    item->string);
	}

	if (!access(mkpath("%s/shallow", ref_git), F_OK))
		die(_("reference repository '%s' is shallow"), item->string);

	if (!access(mkpath("%s/info/grafts", ref_git), F_OK))
		die(_("reference repository '%s' is grafted"), item->string);

	strbuf_addf(&alternate, "%s/objects", ref_git);
	add_to_alternates_file(alternate.buf);
	strbuf_release(&alternate);
	free(ref_git);
	return 0;
}

static void setup_reference(void)
{
	for_each_string_list(&option_reference, add_one_reference, NULL);
}

static void copy_alternates(struct strbuf *src, struct strbuf *dst,
			    const char *src_repo)
{
	/*
	 * Read from the source objects/info/alternates file
	 * and copy the entries to corresponding file in the
	 * destination repository with add_to_alternates_file().
	 * Both src and dst have "$path/objects/info/alternates".
	 *
	 * Instead of copying bit-for-bit from the original,
	 * we need to append to existing one so that the already
	 * created entry via "clone -s" is not lost, and also
	 * to turn entries with paths relative to the original
	 * absolute, so that they can be used in the new repository.
	 */
	FILE *in = fopen(src->buf, "r");
	struct strbuf line = STRBUF_INIT;

	while (strbuf_getline(&line, in, '\n') != EOF) {
		char *abs_path;
		if (!line.len || line.buf[0] == '#')
			continue;
		if (is_absolute_path(line.buf)) {
			add_to_alternates_file(line.buf);
			continue;
		}
		abs_path = mkpathdup("%s/objects/%s", src_repo, line.buf);
		normalize_path_copy(abs_path, abs_path);
		add_to_alternates_file(abs_path);
		free(abs_path);
	}
	strbuf_release(&line);
	fclose(in);
}

static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
				   const char *src_repo, int src_baselen)
{
	struct dirent *de;
	struct stat buf;
	int src_len, dest_len;
	DIR *dir;

	dir = opendir(src->buf);
	if (!dir)
		die_errno(_("failed to open '%s'"), src->buf);

	if (mkdir(dest->buf, 0777)) {
		if (errno != EEXIST)
			die_errno(_("failed to create directory '%s'"), dest->buf);
		else if (stat(dest->buf, &buf))
			die_errno(_("failed to stat '%s'"), dest->buf);
		else if (!S_ISDIR(buf.st_mode))
			die(_("%s exists and is not a directory"), dest->buf);
	}

	strbuf_addch(src, '/');
	src_len = src->len;
	strbuf_addch(dest, '/');
	dest_len = dest->len;

	while ((de = readdir(dir)) != NULL) {
		strbuf_setlen(src, src_len);
		strbuf_addstr(src, de->d_name);
		strbuf_setlen(dest, dest_len);
		strbuf_addstr(dest, de->d_name);
		if (stat(src->buf, &buf)) {
			warning (_("failed to stat %s\n"), src->buf);
			continue;
		}
		if (S_ISDIR(buf.st_mode)) {
			if (de->d_name[0] != '.')
				copy_or_link_directory(src, dest,
						       src_repo, src_baselen);
			continue;
		}

		/* Files that cannot be copied bit-for-bit... */
		if (!strcmp(src->buf + src_baselen, "/info/alternates")) {
			copy_alternates(src, dest, src_repo);
			continue;
		}

		if (unlink(dest->buf) && errno != ENOENT)
			die_errno(_("failed to unlink '%s'"), dest->buf);
		if (!option_no_hardlinks) {
			if (!link(src->buf, dest->buf))
				continue;
			if (option_local > 0)
				die_errno(_("failed to create link '%s'"), dest->buf);
			option_no_hardlinks = 1;
		}
		if (copy_file_with_time(dest->buf, src->buf, 0666))
			die_errno(_("failed to copy file to '%s'"), dest->buf);
	}
	closedir(dir);
}

static void clone_local(const char *src_repo, const char *dest_repo)
{
	if (option_shared) {
		struct strbuf alt = STRBUF_INIT;
		strbuf_addf(&alt, "%s/objects", src_repo);
		add_to_alternates_file(alt.buf);
		strbuf_release(&alt);
	} else {
		struct strbuf src = STRBUF_INIT;
		struct strbuf dest = STRBUF_INIT;
		get_common_dir(&src, src_repo);
		get_common_dir(&dest, dest_repo);
		strbuf_addstr(&src, "/objects");
		strbuf_addstr(&dest, "/objects");
		copy_or_link_directory(&src, &dest, src_repo, src.len);
		strbuf_release(&src);
		strbuf_release(&dest);
	}

	if (0 <= option_verbosity)
		fprintf(stderr, _("done.\n"));
}

static const char *junk_work_tree;
static const char *junk_git_dir;
static enum {
	JUNK_LEAVE_NONE,
	JUNK_LEAVE_REPO,
	JUNK_LEAVE_ALL
} junk_mode = JUNK_LEAVE_NONE;

static const char junk_leave_repo_msg[] =
N_("Clone succeeded, but checkout failed.\n"
   "You can inspect what was checked out with 'git status'\n"
   "and retry the checkout with 'git checkout -f HEAD'\n");

static void remove_junk(void)
{
	struct strbuf sb = STRBUF_INIT;

	switch (junk_mode) {
	case JUNK_LEAVE_REPO:
		warning("%s", _(junk_leave_repo_msg));
		/* fall-through */
	case JUNK_LEAVE_ALL:
		return;
	default:
		/* proceed to removal */
		break;
	}

	if (junk_git_dir) {
		strbuf_addstr(&sb, junk_git_dir);
		remove_dir_recursively(&sb, 0);
		strbuf_reset(&sb);
	}
	if (junk_work_tree) {
		strbuf_addstr(&sb, junk_work_tree);
		remove_dir_recursively(&sb, 0);
		strbuf_reset(&sb);
	}
}

static void remove_junk_on_signal(int signo)
{
	remove_junk();
	sigchain_pop(signo);
	raise(signo);
}

static struct ref *find_remote_branch(const struct ref *refs, const char *branch)
{
	struct ref *ref;
	struct strbuf head = STRBUF_INIT;
	strbuf_addstr(&head, "refs/heads/");
	strbuf_addstr(&head, branch);
	ref = find_ref_by_name(refs, head.buf);
	strbuf_release(&head);

	if (ref)
		return ref;

	strbuf_addstr(&head, "refs/tags/");
	strbuf_addstr(&head, branch);
	ref = find_ref_by_name(refs, head.buf);
	strbuf_release(&head);

	return ref;
}

static struct ref *wanted_peer_refs(const struct ref *refs,
		struct refspec *refspec)
{
	struct ref *head = copy_ref(find_ref_by_name(refs, "HEAD"));
	struct ref *local_refs = head;
	struct ref **tail = head ? &head->next : &local_refs;

	if (option_single_branch) {
		struct ref *remote_head = NULL;

		if (!option_branch)
			remote_head = guess_remote_head(head, refs, 0);
		else {
			local_refs = NULL;
			tail = &local_refs;
			remote_head = copy_ref(find_remote_branch(refs, option_branch));
		}

		if (!remote_head && option_branch)
			warning(_("Could not find remote branch %s to clone."),
				option_branch);
		else {
			get_fetch_map(remote_head, refspec, &tail, 0);

			/* if --branch=tag, pull the requested tag explicitly */
			get_fetch_map(remote_head, tag_refspec, &tail, 0);
		}
	} else
		get_fetch_map(refs, refspec, &tail, 0);

	if (!option_mirror && !option_single_branch)
		get_fetch_map(refs, tag_refspec, &tail, 0);

	return local_refs;
}

static void write_remote_refs(const struct ref *local_refs)
{
	const struct ref *r;

	struct ref_transaction *t;
	struct strbuf err = STRBUF_INIT;

	t = ref_transaction_begin(&err);
	if (!t)
		die("%s", err.buf);

	for (r = local_refs; r; r = r->next) {
		if (!r->peer_ref)
			continue;
		if (ref_transaction_create(t, r->peer_ref->name, r->old_sha1,
					   0, NULL, &err))
			die("%s", err.buf);
	}

	if (initial_ref_transaction_commit(t, &err))
		die("%s", err.buf);

	strbuf_release(&err);
	ref_transaction_free(t);
}

static void write_followtags(const struct ref *refs, const char *msg)
{
	const struct ref *ref;
	for (ref = refs; ref; ref = ref->next) {
		if (!starts_with(ref->name, "refs/tags/"))
			continue;
		if (ends_with(ref->name, "^{}"))
			continue;
		if (!has_sha1_file(ref->old_sha1))
			continue;
		update_ref(msg, ref->name, ref->old_sha1,
			   NULL, 0, UPDATE_REFS_DIE_ON_ERR);
	}
}

static int iterate_ref_map(void *cb_data, unsigned char sha1[20])
{
	struct ref **rm = cb_data;
	struct ref *ref = *rm;

	/*
	 * Skip anything missing a peer_ref, which we are not
	 * actually going to write a ref for.
	 */
	while (ref && !ref->peer_ref)
		ref = ref->next;
	/* Returning -1 notes "end of list" to the caller. */
	if (!ref)
		return -1;

	hashcpy(sha1, ref->old_sha1);
	*rm = ref->next;
	return 0;
}

static void update_remote_refs(const struct ref *refs,
			       const struct ref *mapped_refs,
			       const struct ref *remote_head_points_at,
			       const char *branch_top,
			       const char *msg,
			       struct transport *transport,
			       int check_connectivity)
{
	const struct ref *rm = mapped_refs;

	if (check_connectivity) {
		if (transport->progress)
			fprintf(stderr, _("Checking connectivity... "));
		if (check_everything_connected_with_transport(iterate_ref_map,
							      0, &rm, transport))
			die(_("remote did not send all necessary objects"));
		if (transport->progress)
			fprintf(stderr, _("done.\n"));
	}

	if (refs) {
		write_remote_refs(mapped_refs);
		if (option_single_branch)
			write_followtags(refs, msg);
	}

	if (remote_head_points_at && !option_bare) {
		struct strbuf head_ref = STRBUF_INIT;
		strbuf_addstr(&head_ref, branch_top);
		strbuf_addstr(&head_ref, "HEAD");
		create_symref(head_ref.buf,
			      remote_head_points_at->peer_ref->name,
			      msg);
	}
}

static void update_head(const struct ref *our, const struct ref *remote,
			const char *msg)
{
	const char *head;
	if (our && skip_prefix(our->name, "refs/heads/", &head)) {
		/* Local default branch link */
		create_symref("HEAD", our->name, NULL);
		if (!option_bare) {
			update_ref(msg, "HEAD", our->old_sha1, NULL, 0,
				   UPDATE_REFS_DIE_ON_ERR);
			install_branch_config(0, head, option_origin, our->name);
		}
	} else if (our) {
		struct commit *c = lookup_commit_reference(our->old_sha1);
		/* --branch specifies a non-branch (i.e. tags), detach HEAD */
		update_ref(msg, "HEAD", c->object.sha1,
			   NULL, REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
	} else if (remote) {
		/*
		 * We know remote HEAD points to a non-branch, or
		 * HEAD points to a branch but we don't know which one.
		 * Detach HEAD in all these cases.
		 */
		update_ref(msg, "HEAD", remote->old_sha1,
			   NULL, REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
	}
}

static int checkout(void)
{
	unsigned char sha1[20];
	char *head;
	struct lock_file *lock_file;
	struct unpack_trees_options opts;
	struct tree *tree;
	struct tree_desc t;
	int err = 0;

	if (option_no_checkout)
		return 0;

	head = resolve_refdup("HEAD", RESOLVE_REF_READING, sha1, NULL);
	if (!head) {
		warning(_("remote HEAD refers to nonexistent ref, "
			  "unable to checkout.\n"));
		return 0;
	}
	if (!strcmp(head, "HEAD")) {
		if (advice_detached_head)
			detach_advice(sha1_to_hex(sha1));
	} else {
		if (!starts_with(head, "refs/heads/"))
			die(_("HEAD not found below refs/heads!"));
	}
	free(head);

	/* We need to be in the new work tree for the checkout */
	setup_work_tree();

	lock_file = xcalloc(1, sizeof(struct lock_file));
	hold_locked_index(lock_file, 1);

	memset(&opts, 0, sizeof opts);
	opts.update = 1;
	opts.merge = 1;
	opts.fn = oneway_merge;
	opts.verbose_update = (option_verbosity >= 0);
	opts.src_index = &the_index;
	opts.dst_index = &the_index;

	tree = parse_tree_indirect(sha1);
	parse_tree(tree);
	init_tree_desc(&t, tree->buffer, tree->size);
	if (unpack_trees(1, &t, &opts) < 0)
		die(_("unable to checkout working tree"));

	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
		die(_("unable to write new index file"));

	err |= run_hook_le(NULL, "post-checkout", sha1_to_hex(null_sha1),
			   sha1_to_hex(sha1), "1", NULL);

	if (!err && option_recursive)
		err = run_command_v_opt(argv_submodule, RUN_GIT_CMD);

	return err;
}

static int write_one_config(const char *key, const char *value, void *data)
{
	return git_config_set_multivar(key, value ? value : "true", "^$", 0);
}

static void write_config(struct string_list *config)
{
	int i;

	for (i = 0; i < config->nr; i++) {
		if (git_config_parse_parameter(config->items[i].string,
					       write_one_config, NULL) < 0)
			die("unable to write parameters to config file");
	}
}

static void write_refspec_config(const char *src_ref_prefix,
		const struct ref *our_head_points_at,
		const struct ref *remote_head_points_at,
		struct strbuf *branch_top)
{
	struct strbuf key = STRBUF_INIT;
	struct strbuf value = STRBUF_INIT;

	if (option_mirror || !option_bare) {
		if (option_single_branch && !option_mirror) {
			if (option_branch) {
				if (starts_with(our_head_points_at->name, "refs/tags/"))
					strbuf_addf(&value, "+%s:%s", our_head_points_at->name,
						our_head_points_at->name);
				else
					strbuf_addf(&value, "+%s:%s%s", our_head_points_at->name,
						branch_top->buf, option_branch);
			} else if (remote_head_points_at) {
				const char *head = remote_head_points_at->name;
				if (!skip_prefix(head, "refs/heads/", &head))
					die("BUG: remote HEAD points at non-head?");

				strbuf_addf(&value, "+%s:%s%s", remote_head_points_at->name,
						branch_top->buf, head);
			}
			/*
			 * otherwise, the next "git fetch" will
			 * simply fetch from HEAD without updating
			 * any remote-tracking branch, which is what
			 * we want.
			 */
		} else {
			strbuf_addf(&value, "+%s*:%s*", src_ref_prefix, branch_top->buf);
		}
		/* Configure the remote */
		if (value.len) {
			strbuf_addf(&key, "remote.%s.fetch", option_origin);
			git_config_set_multivar(key.buf, value.buf, "^$", 0);
			strbuf_reset(&key);

			if (option_mirror) {
				strbuf_addf(&key, "remote.%s.mirror", option_origin);
				git_config_set(key.buf, "true");
				strbuf_reset(&key);
			}
		}
	}

	strbuf_release(&key);
	strbuf_release(&value);
}

static void dissociate_from_references(void)
{
	static const char* argv[] = { "repack", "-a", "-d", NULL };
	char *alternates = git_pathdup("objects/info/alternates");

	if (!access(alternates, F_OK)) {
		if (run_command_v_opt(argv, RUN_GIT_CMD|RUN_COMMAND_NO_STDIN))
			die(_("cannot repack to clean up"));
		if (unlink(alternates) && errno != ENOENT)
			die_errno(_("cannot unlink temporary alternates file"));
	}
	free(alternates);
}

int cmd_clone(int argc, const char **argv, const char *prefix)
{
	int is_bundle = 0, is_local;
	struct stat buf;
	const char *repo_name, *repo, *work_tree, *git_dir;
	char *path, *dir;
	int dest_exists;
	const struct ref *refs, *remote_head;
	const struct ref *remote_head_points_at;
	const struct ref *our_head_points_at;
	struct ref *mapped_refs;
	const struct ref *ref;
	struct strbuf key = STRBUF_INIT, value = STRBUF_INIT;
	struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
	struct transport *transport = NULL;
	const char *src_ref_prefix = "refs/heads/";
	struct remote *remote;
	int err = 0, complete_refs_before_fetch = 1;

	struct refspec *refspec;
	const char *fetch_pattern;

	packet_trace_identity("clone");
	argc = parse_options(argc, argv, prefix, builtin_clone_options,
			     builtin_clone_usage, 0);

	if (argc > 2)
		usage_msg_opt(_("Too many arguments."),
			builtin_clone_usage, builtin_clone_options);

	if (argc == 0)
		usage_msg_opt(_("You must specify a repository to clone."),
			builtin_clone_usage, builtin_clone_options);

	if (option_single_branch == -1)
		option_single_branch = option_depth ? 1 : 0;

	if (option_mirror)
		option_bare = 1;

	if (option_bare) {
		if (option_origin)
			die(_("--bare and --origin %s options are incompatible."),
			    option_origin);
		if (real_git_dir)
			die(_("--bare and --separate-git-dir are incompatible."));
		option_no_checkout = 1;
	}

	if (!option_origin)
		option_origin = "origin";

	repo_name = argv[0];

	path = get_repo_path(repo_name, &is_bundle);
	if (path)
		repo = xstrdup(absolute_path(repo_name));
	else if (!strchr(repo_name, ':'))
		die(_("repository '%s' does not exist"), repo_name);
	else
		repo = repo_name;

	/* no need to be strict, transport_set_option() will validate it again */
	if (option_depth && atoi(option_depth) < 1)
		die(_("depth %s is not a positive number"), option_depth);

	if (argc == 2)
		dir = xstrdup(argv[1]);
	else
		dir = guess_dir_name(repo_name, is_bundle, option_bare);
	strip_trailing_slashes(dir);

	dest_exists = !stat(dir, &buf);
	if (dest_exists && !is_empty_dir(dir))
		die(_("destination path '%s' already exists and is not "
			"an empty directory."), dir);

	strbuf_addf(&reflog_msg, "clone: from %s", repo);

	if (option_bare)
		work_tree = NULL;
	else {
		work_tree = getenv("GIT_WORK_TREE");
		if (work_tree && !stat(work_tree, &buf))
			die(_("working tree '%s' already exists."), work_tree);
	}

	if (option_bare || work_tree)
		git_dir = xstrdup(dir);
	else {
		work_tree = dir;
		git_dir = mkpathdup("%s/.git", dir);
	}

	atexit(remove_junk);
	sigchain_push_common(remove_junk_on_signal);

	if (!option_bare) {
		if (safe_create_leading_directories_const(work_tree) < 0)
			die_errno(_("could not create leading directories of '%s'"),
				  work_tree);
		if (!dest_exists && mkdir(work_tree, 0777))
			die_errno(_("could not create work tree dir '%s'"),
				  work_tree);
		junk_work_tree = work_tree;
		set_git_work_tree(work_tree);
	}

	junk_git_dir = git_dir;
	if (safe_create_leading_directories_const(git_dir) < 0)
		die(_("could not create leading directories of '%s'"), git_dir);

	set_git_dir_init(git_dir, real_git_dir, 0);
	if (real_git_dir) {
		git_dir = real_git_dir;
		junk_git_dir = real_git_dir;
	}

	if (0 <= option_verbosity) {
		if (option_bare)
			fprintf(stderr, _("Cloning into bare repository '%s'...\n"), dir);
		else
			fprintf(stderr, _("Cloning into '%s'...\n"), dir);
	}
	init_db(option_template, INIT_DB_QUIET);
	write_config(&option_config);

	git_config(git_default_config, NULL);

	if (option_bare) {
		if (option_mirror)
			src_ref_prefix = "refs/";
		strbuf_addstr(&branch_top, src_ref_prefix);

		git_config_set("core.bare", "true");
	} else {
		strbuf_addf(&branch_top, "refs/remotes/%s/", option_origin);
	}

	strbuf_addf(&value, "+%s*:%s*", src_ref_prefix, branch_top.buf);
	strbuf_addf(&key, "remote.%s.url", option_origin);
	git_config_set(key.buf, repo);
	strbuf_reset(&key);

	if (option_reference.nr)
		setup_reference();

	fetch_pattern = value.buf;
	refspec = parse_fetch_refspec(1, &fetch_pattern);

	strbuf_reset(&value);

	remote = remote_get(option_origin);
	transport = transport_get(remote, remote->url[0]);
	transport_set_verbosity(transport, option_verbosity, option_progress);

	path = get_repo_path(remote->url[0], &is_bundle);
	is_local = option_local != 0 && path && !is_bundle;
	if (is_local) {
		if (option_depth)
			warning(_("--depth is ignored in local clones; use file:// instead."));
		if (!access(mkpath("%s/shallow", path), F_OK)) {
			if (option_local > 0)
				warning(_("source repository is shallow, ignoring --local"));
			is_local = 0;
		}
	}
	if (option_local > 0 && !is_local)
		warning(_("--local is ignored"));
	transport->cloning = 1;

	if (!transport->get_refs_list || (!is_local && !transport->fetch))
		die(_("Don't know how to clone %s"), transport->url);

	transport_set_option(transport, TRANS_OPT_KEEP, "yes");

	if (option_depth)
		transport_set_option(transport, TRANS_OPT_DEPTH,
				     option_depth);
	if (option_single_branch)
		transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");

	if (option_upload_pack)
		transport_set_option(transport, TRANS_OPT_UPLOADPACK,
				     option_upload_pack);

	if (transport->smart_options && !option_depth)
		transport->smart_options->check_self_contained_and_connected = 1;

	refs = transport_get_remote_refs(transport);

	if (refs) {
		mapped_refs = wanted_peer_refs(refs, refspec);
		/*
		 * transport_get_remote_refs() may return refs with null sha-1
		 * in mapped_refs (see struct transport->get_refs_list
		 * comment). In that case we need fetch it early because
		 * remote_head code below relies on it.
		 *
		 * for normal clones, transport_get_remote_refs() should
		 * return reliable ref set, we can delay cloning until after
		 * remote HEAD check.
		 */
		for (ref = refs; ref; ref = ref->next)
			if (is_null_sha1(ref->old_sha1)) {
				complete_refs_before_fetch = 0;
				break;
			}

		if (!is_local && !complete_refs_before_fetch)
			transport_fetch_refs(transport, mapped_refs);

		remote_head = find_ref_by_name(refs, "HEAD");
		remote_head_points_at =
			guess_remote_head(remote_head, mapped_refs, 0);

		if (option_branch) {
			our_head_points_at =
				find_remote_branch(mapped_refs, option_branch);

			if (!our_head_points_at)
				die(_("Remote branch %s not found in upstream %s"),
				    option_branch, option_origin);
		}
		else
			our_head_points_at = remote_head_points_at;
	}
	else {
		if (option_branch)
			die(_("Remote branch %s not found in upstream %s"),
					option_branch, option_origin);

		warning(_("You appear to have cloned an empty repository."));
		mapped_refs = NULL;
		our_head_points_at = NULL;
		remote_head_points_at = NULL;
		remote_head = NULL;
		option_no_checkout = 1;
		if (!option_bare)
			install_branch_config(0, "master", option_origin,
					      "refs/heads/master");
	}

	write_refspec_config(src_ref_prefix, our_head_points_at,
			remote_head_points_at, &branch_top);

	if (is_local)
		clone_local(path, git_dir);
	else if (refs && complete_refs_before_fetch)
		transport_fetch_refs(transport, mapped_refs);

	update_remote_refs(refs, mapped_refs, remote_head_points_at,
			   branch_top.buf, reflog_msg.buf, transport, !is_local);

	update_head(our_head_points_at, remote_head, reflog_msg.buf);

	transport_unlock_pack(transport);
	transport_disconnect(transport);

	if (option_dissociate) {
		close_all_packs();
		dissociate_from_references();
	}

	junk_mode = JUNK_LEAVE_REPO;
	err = checkout();

	strbuf_release(&reflog_msg);
	strbuf_release(&branch_top);
	strbuf_release(&key);
	strbuf_release(&value);
	junk_mode = JUNK_LEAVE_ALL;

	free(refspec);
	return err;
}