Documentation/git-reset: don't mention --mixed for selected-paths reset
[git] / remote.c
1 #include "cache.h"
2 #include "remote.h"
3 #include "refs.h"
4
5 static struct remote **remotes;
6 static int allocated_remotes;
7
8 static struct branch **branches;
9 static int allocated_branches;
10
11 static struct branch *current_branch;
12 static const char *default_remote_name;
13
14 #define BUF_SIZE (2048)
15 static char buffer[BUF_SIZE];
16
17 static void add_push_refspec(struct remote *remote, const char *ref)
18 {
19         int nr = remote->push_refspec_nr + 1;
20         remote->push_refspec =
21                 xrealloc(remote->push_refspec, nr * sizeof(char *));
22         remote->push_refspec[nr-1] = ref;
23         remote->push_refspec_nr = nr;
24 }
25
26 static void add_fetch_refspec(struct remote *remote, const char *ref)
27 {
28         int nr = remote->fetch_refspec_nr + 1;
29         remote->fetch_refspec =
30                 xrealloc(remote->fetch_refspec, nr * sizeof(char *));
31         remote->fetch_refspec[nr-1] = ref;
32         remote->fetch_refspec_nr = nr;
33 }
34
35 static void add_url(struct remote *remote, const char *url)
36 {
37         int nr = remote->url_nr + 1;
38         remote->url =
39                 xrealloc(remote->url, nr * sizeof(char *));
40         remote->url[nr-1] = url;
41         remote->url_nr = nr;
42 }
43
44 static struct remote *make_remote(const char *name, int len)
45 {
46         int i, empty = -1;
47
48         for (i = 0; i < allocated_remotes; i++) {
49                 if (!remotes[i]) {
50                         if (empty < 0)
51                                 empty = i;
52                 } else {
53                         if (len ? (!strncmp(name, remotes[i]->name, len) &&
54                                    !remotes[i]->name[len]) :
55                             !strcmp(name, remotes[i]->name))
56                                 return remotes[i];
57                 }
58         }
59
60         if (empty < 0) {
61                 empty = allocated_remotes;
62                 allocated_remotes += allocated_remotes ? allocated_remotes : 1;
63                 remotes = xrealloc(remotes,
64                                    sizeof(*remotes) * allocated_remotes);
65                 memset(remotes + empty, 0,
66                        (allocated_remotes - empty) * sizeof(*remotes));
67         }
68         remotes[empty] = xcalloc(1, sizeof(struct remote));
69         if (len)
70                 remotes[empty]->name = xstrndup(name, len);
71         else
72                 remotes[empty]->name = xstrdup(name);
73         return remotes[empty];
74 }
75
76 static void add_merge(struct branch *branch, const char *name)
77 {
78         int nr = branch->merge_nr + 1;
79         branch->merge_name =
80                 xrealloc(branch->merge_name, nr * sizeof(char *));
81         branch->merge_name[nr-1] = name;
82         branch->merge_nr = nr;
83 }
84
85 static struct branch *make_branch(const char *name, int len)
86 {
87         int i, empty = -1;
88         char *refname;
89
90         for (i = 0; i < allocated_branches; i++) {
91                 if (!branches[i]) {
92                         if (empty < 0)
93                                 empty = i;
94                 } else {
95                         if (len ? (!strncmp(name, branches[i]->name, len) &&
96                                    !branches[i]->name[len]) :
97                             !strcmp(name, branches[i]->name))
98                                 return branches[i];
99                 }
100         }
101
102         if (empty < 0) {
103                 empty = allocated_branches;
104                 allocated_branches += allocated_branches ? allocated_branches : 1;
105                 branches = xrealloc(branches,
106                                    sizeof(*branches) * allocated_branches);
107                 memset(branches + empty, 0,
108                        (allocated_branches - empty) * sizeof(*branches));
109         }
110         branches[empty] = xcalloc(1, sizeof(struct branch));
111         if (len)
112                 branches[empty]->name = xstrndup(name, len);
113         else
114                 branches[empty]->name = xstrdup(name);
115         refname = malloc(strlen(name) + strlen("refs/heads/") + 1);
116         strcpy(refname, "refs/heads/");
117         strcpy(refname + strlen("refs/heads/"),
118                branches[empty]->name);
119         branches[empty]->refname = refname;
120
121         return branches[empty];
122 }
123
124 static void read_remotes_file(struct remote *remote)
125 {
126         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
127
128         if (!f)
129                 return;
130         while (fgets(buffer, BUF_SIZE, f)) {
131                 int value_list;
132                 char *s, *p;
133
134                 if (!prefixcmp(buffer, "URL:")) {
135                         value_list = 0;
136                         s = buffer + 4;
137                 } else if (!prefixcmp(buffer, "Push:")) {
138                         value_list = 1;
139                         s = buffer + 5;
140                 } else if (!prefixcmp(buffer, "Pull:")) {
141                         value_list = 2;
142                         s = buffer + 5;
143                 } else
144                         continue;
145
146                 while (isspace(*s))
147                         s++;
148                 if (!*s)
149                         continue;
150
151                 p = s + strlen(s);
152                 while (isspace(p[-1]))
153                         *--p = 0;
154
155                 switch (value_list) {
156                 case 0:
157                         add_url(remote, xstrdup(s));
158                         break;
159                 case 1:
160                         add_push_refspec(remote, xstrdup(s));
161                         break;
162                 case 2:
163                         add_fetch_refspec(remote, xstrdup(s));
164                         break;
165                 }
166         }
167         fclose(f);
168 }
169
170 static void read_branches_file(struct remote *remote)
171 {
172         const char *slash = strchr(remote->name, '/');
173         char *frag;
174         char *branch;
175         int n = slash ? slash - remote->name : 1000;
176         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
177         char *s, *p;
178         int len;
179
180         if (!f)
181                 return;
182         s = fgets(buffer, BUF_SIZE, f);
183         fclose(f);
184         if (!s)
185                 return;
186         while (isspace(*s))
187                 s++;
188         if (!*s)
189                 return;
190         p = s + strlen(s);
191         while (isspace(p[-1]))
192                 *--p = 0;
193         len = p - s;
194         if (slash)
195                 len += strlen(slash);
196         p = xmalloc(len + 1);
197         strcpy(p, s);
198         if (slash)
199                 strcat(p, slash);
200         frag = strchr(p, '#');
201         if (frag) {
202                 *(frag++) = '\0';
203                 branch = xmalloc(strlen(frag) + 12);
204                 strcpy(branch, "refs/heads/");
205                 strcat(branch, frag);
206         } else {
207                 branch = "refs/heads/master";
208         }
209         add_url(remote, p);
210         add_fetch_refspec(remote, branch);
211         remote->fetch_tags = 1; /* always auto-follow */
212 }
213
214 static int handle_config(const char *key, const char *value)
215 {
216         const char *name;
217         const char *subkey;
218         struct remote *remote;
219         struct branch *branch;
220         if (!prefixcmp(key, "branch.")) {
221                 name = key + 7;
222                 subkey = strrchr(name, '.');
223                 if (!subkey)
224                         return 0;
225                 branch = make_branch(name, subkey - name);
226                 if (!strcmp(subkey, ".remote")) {
227                         if (!value)
228                                 return config_error_nonbool(key);
229                         branch->remote_name = xstrdup(value);
230                         if (branch == current_branch)
231                                 default_remote_name = branch->remote_name;
232                 } else if (!strcmp(subkey, ".merge")) {
233                         if (!value)
234                                 return config_error_nonbool(key);
235                         add_merge(branch, xstrdup(value));
236                 }
237                 return 0;
238         }
239         if (prefixcmp(key,  "remote."))
240                 return 0;
241         name = key + 7;
242         subkey = strrchr(name, '.');
243         if (!subkey)
244                 return error("Config with no key for remote %s", name);
245         if (*subkey == '/') {
246                 warning("Config remote shorthand cannot begin with '/': %s", name);
247                 return 0;
248         }
249         remote = make_remote(name, subkey - name);
250         if (!value) {
251                 /* if we ever have a boolean variable, e.g. "remote.*.disabled"
252                  * [remote "frotz"]
253                  *      disabled
254                  * is a valid way to set it to true; we get NULL in value so
255                  * we need to handle it here.
256                  *
257                  * if (!strcmp(subkey, ".disabled")) {
258                  *      val = git_config_bool(key, value);
259                  *      return 0;
260                  * } else
261                  *
262                  */
263                 return 0; /* ignore unknown booleans */
264         }
265         if (!strcmp(subkey, ".url")) {
266                 add_url(remote, xstrdup(value));
267         } else if (!strcmp(subkey, ".push")) {
268                 add_push_refspec(remote, xstrdup(value));
269         } else if (!strcmp(subkey, ".fetch")) {
270                 add_fetch_refspec(remote, xstrdup(value));
271         } else if (!strcmp(subkey, ".receivepack")) {
272                 if (!remote->receivepack)
273                         remote->receivepack = xstrdup(value);
274                 else
275                         error("more than one receivepack given, using the first");
276         } else if (!strcmp(subkey, ".uploadpack")) {
277                 if (!remote->uploadpack)
278                         remote->uploadpack = xstrdup(value);
279                 else
280                         error("more than one uploadpack given, using the first");
281         } else if (!strcmp(subkey, ".tagopt")) {
282                 if (!strcmp(value, "--no-tags"))
283                         remote->fetch_tags = -1;
284         } else if (!strcmp(subkey, ".proxy")) {
285                 remote->http_proxy = xstrdup(value);
286         }
287         return 0;
288 }
289
290 static void read_config(void)
291 {
292         unsigned char sha1[20];
293         const char *head_ref;
294         int flag;
295         if (default_remote_name) // did this already
296                 return;
297         default_remote_name = xstrdup("origin");
298         current_branch = NULL;
299         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
300         if (head_ref && (flag & REF_ISSYMREF) &&
301             !prefixcmp(head_ref, "refs/heads/")) {
302                 current_branch =
303                         make_branch(head_ref + strlen("refs/heads/"), 0);
304         }
305         git_config(handle_config);
306 }
307
308 struct refspec *parse_ref_spec(int nr_refspec, const char **refspec)
309 {
310         int i;
311         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
312         for (i = 0; i < nr_refspec; i++) {
313                 const char *sp, *ep, *gp;
314                 sp = refspec[i];
315                 if (*sp == '+') {
316                         rs[i].force = 1;
317                         sp++;
318                 }
319                 gp = strchr(sp, '*');
320                 ep = strchr(sp, ':');
321                 if (gp && ep && gp > ep)
322                         gp = NULL;
323                 if (ep) {
324                         if (ep[1]) {
325                                 const char *glob = strchr(ep + 1, '*');
326                                 if (!glob)
327                                         gp = NULL;
328                                 if (gp)
329                                         rs[i].dst = xstrndup(ep + 1,
330                                                              glob - ep - 1);
331                                 else
332                                         rs[i].dst = xstrdup(ep + 1);
333                         }
334                 } else {
335                         ep = sp + strlen(sp);
336                 }
337                 if (gp) {
338                         rs[i].pattern = 1;
339                         ep = gp;
340                 }
341                 rs[i].src = xstrndup(sp, ep - sp);
342         }
343         return rs;
344 }
345
346 static int valid_remote_nick(const char *name)
347 {
348         if (!name[0] || /* not empty */
349             (name[0] == '.' && /* not "." */
350              (!name[1] || /* not ".." */
351               (name[1] == '.' && !name[2]))))
352                 return 0;
353         return !strchr(name, '/'); /* no slash */
354 }
355
356 struct remote *remote_get(const char *name)
357 {
358         struct remote *ret;
359
360         read_config();
361         if (!name)
362                 name = default_remote_name;
363         ret = make_remote(name, 0);
364         if (valid_remote_nick(name)) {
365                 if (!ret->url)
366                         read_remotes_file(ret);
367                 if (!ret->url)
368                         read_branches_file(ret);
369         }
370         if (!ret->url)
371                 add_url(ret, name);
372         if (!ret->url)
373                 return NULL;
374         ret->fetch = parse_ref_spec(ret->fetch_refspec_nr, ret->fetch_refspec);
375         ret->push = parse_ref_spec(ret->push_refspec_nr, ret->push_refspec);
376         return ret;
377 }
378
379 int for_each_remote(each_remote_fn fn, void *priv)
380 {
381         int i, result = 0;
382         read_config();
383         for (i = 0; i < allocated_remotes && !result; i++) {
384                 struct remote *r = remotes[i];
385                 if (!r)
386                         continue;
387                 if (!r->fetch)
388                         r->fetch = parse_ref_spec(r->fetch_refspec_nr,
389                                         r->fetch_refspec);
390                 if (!r->push)
391                         r->push = parse_ref_spec(r->push_refspec_nr,
392                                         r->push_refspec);
393                 result = fn(r, priv);
394         }
395         return result;
396 }
397
398 void ref_remove_duplicates(struct ref *ref_map)
399 {
400         struct ref **posn;
401         struct ref *next;
402         for (; ref_map; ref_map = ref_map->next) {
403                 if (!ref_map->peer_ref)
404                         continue;
405                 posn = &ref_map->next;
406                 while (*posn) {
407                         if ((*posn)->peer_ref &&
408                             !strcmp((*posn)->peer_ref->name,
409                                     ref_map->peer_ref->name)) {
410                                 if (strcmp((*posn)->name, ref_map->name))
411                                         die("%s tracks both %s and %s",
412                                             ref_map->peer_ref->name,
413                                             (*posn)->name, ref_map->name);
414                                 next = (*posn)->next;
415                                 free((*posn)->peer_ref);
416                                 free(*posn);
417                                 *posn = next;
418                         } else {
419                                 posn = &(*posn)->next;
420                         }
421                 }
422         }
423 }
424
425 int remote_has_url(struct remote *remote, const char *url)
426 {
427         int i;
428         for (i = 0; i < remote->url_nr; i++) {
429                 if (!strcmp(remote->url[i], url))
430                         return 1;
431         }
432         return 0;
433 }
434
435 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
436 {
437         int find_src = refspec->src == NULL;
438         char *needle, **result;
439         int i;
440
441         if (find_src) {
442                 if (!refspec->dst)
443                         return error("find_tracking: need either src or dst");
444                 needle = refspec->dst;
445                 result = &refspec->src;
446         } else {
447                 needle = refspec->src;
448                 result = &refspec->dst;
449         }
450
451         for (i = 0; i < remote->fetch_refspec_nr; i++) {
452                 struct refspec *fetch = &remote->fetch[i];
453                 const char *key = find_src ? fetch->dst : fetch->src;
454                 const char *value = find_src ? fetch->src : fetch->dst;
455                 if (!fetch->dst)
456                         continue;
457                 if (fetch->pattern) {
458                         if (!prefixcmp(needle, key)) {
459                                 *result = xmalloc(strlen(value) +
460                                                   strlen(needle) -
461                                                   strlen(key) + 1);
462                                 strcpy(*result, value);
463                                 strcpy(*result + strlen(value),
464                                        needle + strlen(key));
465                                 refspec->force = fetch->force;
466                                 return 0;
467                         }
468                 } else if (!strcmp(needle, key)) {
469                         *result = xstrdup(value);
470                         refspec->force = fetch->force;
471                         return 0;
472                 }
473         }
474         return -1;
475 }
476
477 struct ref *alloc_ref(unsigned namelen)
478 {
479         struct ref *ret = xmalloc(sizeof(struct ref) + namelen);
480         memset(ret, 0, sizeof(struct ref) + namelen);
481         return ret;
482 }
483
484 static struct ref *copy_ref(const struct ref *ref)
485 {
486         struct ref *ret = xmalloc(sizeof(struct ref) + strlen(ref->name) + 1);
487         memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);
488         ret->next = NULL;
489         return ret;
490 }
491
492 struct ref *copy_ref_list(const struct ref *ref)
493 {
494         struct ref *ret = NULL;
495         struct ref **tail = &ret;
496         while (ref) {
497                 *tail = copy_ref(ref);
498                 ref = ref->next;
499                 tail = &((*tail)->next);
500         }
501         return ret;
502 }
503
504 void free_refs(struct ref *ref)
505 {
506         struct ref *next;
507         while (ref) {
508                 next = ref->next;
509                 if (ref->peer_ref)
510                         free(ref->peer_ref);
511                 free(ref);
512                 ref = next;
513         }
514 }
515
516 static int count_refspec_match(const char *pattern,
517                                struct ref *refs,
518                                struct ref **matched_ref)
519 {
520         int patlen = strlen(pattern);
521         struct ref *matched_weak = NULL;
522         struct ref *matched = NULL;
523         int weak_match = 0;
524         int match = 0;
525
526         for (weak_match = match = 0; refs; refs = refs->next) {
527                 char *name = refs->name;
528                 int namelen = strlen(name);
529
530                 if (!refname_match(pattern, name, ref_rev_parse_rules))
531                         continue;
532
533                 /* A match is "weak" if it is with refs outside
534                  * heads or tags, and did not specify the pattern
535                  * in full (e.g. "refs/remotes/origin/master") or at
536                  * least from the toplevel (e.g. "remotes/origin/master");
537                  * otherwise "git push $URL master" would result in
538                  * ambiguity between remotes/origin/master and heads/master
539                  * at the remote site.
540                  */
541                 if (namelen != patlen &&
542                     patlen != namelen - 5 &&
543                     prefixcmp(name, "refs/heads/") &&
544                     prefixcmp(name, "refs/tags/")) {
545                         /* We want to catch the case where only weak
546                          * matches are found and there are multiple
547                          * matches, and where more than one strong
548                          * matches are found, as ambiguous.  One
549                          * strong match with zero or more weak matches
550                          * are acceptable as a unique match.
551                          */
552                         matched_weak = refs;
553                         weak_match++;
554                 }
555                 else {
556                         matched = refs;
557                         match++;
558                 }
559         }
560         if (!matched) {
561                 *matched_ref = matched_weak;
562                 return weak_match;
563         }
564         else {
565                 *matched_ref = matched;
566                 return match;
567         }
568 }
569
570 static void tail_link_ref(struct ref *ref, struct ref ***tail)
571 {
572         **tail = ref;
573         while (ref->next)
574                 ref = ref->next;
575         *tail = &ref->next;
576 }
577
578 static struct ref *try_explicit_object_name(const char *name)
579 {
580         unsigned char sha1[20];
581         struct ref *ref;
582         int len;
583
584         if (!*name) {
585                 ref = alloc_ref(20);
586                 strcpy(ref->name, "(delete)");
587                 hashclr(ref->new_sha1);
588                 return ref;
589         }
590         if (get_sha1(name, sha1))
591                 return NULL;
592         len = strlen(name) + 1;
593         ref = alloc_ref(len);
594         memcpy(ref->name, name, len);
595         hashcpy(ref->new_sha1, sha1);
596         return ref;
597 }
598
599 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
600 {
601         struct ref *ret;
602         size_t len;
603
604         len = strlen(name) + 1;
605         ret = alloc_ref(len);
606         memcpy(ret->name, name, len);
607         tail_link_ref(ret, tail);
608         return ret;
609 }
610
611 static int match_explicit(struct ref *src, struct ref *dst,
612                           struct ref ***dst_tail,
613                           struct refspec *rs,
614                           int errs)
615 {
616         struct ref *matched_src, *matched_dst;
617
618         const char *dst_value = rs->dst;
619
620         if (rs->pattern)
621                 return errs;
622
623         matched_src = matched_dst = NULL;
624         switch (count_refspec_match(rs->src, src, &matched_src)) {
625         case 1:
626                 break;
627         case 0:
628                 /* The source could be in the get_sha1() format
629                  * not a reference name.  :refs/other is a
630                  * way to delete 'other' ref at the remote end.
631                  */
632                 matched_src = try_explicit_object_name(rs->src);
633                 if (!matched_src)
634                         error("src refspec %s does not match any.", rs->src);
635                 break;
636         default:
637                 matched_src = NULL;
638                 error("src refspec %s matches more than one.", rs->src);
639                 break;
640         }
641
642         if (!matched_src)
643                 errs = 1;
644
645         if (!dst_value) {
646                 if (!matched_src)
647                         return errs;
648                 dst_value = matched_src->name;
649         }
650
651         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
652         case 1:
653                 break;
654         case 0:
655                 if (!memcmp(dst_value, "refs/", 5))
656                         matched_dst = make_linked_ref(dst_value, dst_tail);
657                 else
658                         error("dst refspec %s does not match any "
659                               "existing ref on the remote and does "
660                               "not start with refs/.", dst_value);
661                 break;
662         default:
663                 matched_dst = NULL;
664                 error("dst refspec %s matches more than one.",
665                       dst_value);
666                 break;
667         }
668         if (errs || !matched_dst)
669                 return 1;
670         if (matched_dst->peer_ref) {
671                 errs = 1;
672                 error("dst ref %s receives from more than one src.",
673                       matched_dst->name);
674         }
675         else {
676                 matched_dst->peer_ref = matched_src;
677                 matched_dst->force = rs->force;
678         }
679         return errs;
680 }
681
682 static int match_explicit_refs(struct ref *src, struct ref *dst,
683                                struct ref ***dst_tail, struct refspec *rs,
684                                int rs_nr)
685 {
686         int i, errs;
687         for (i = errs = 0; i < rs_nr; i++)
688                 errs |= match_explicit(src, dst, dst_tail, &rs[i], errs);
689         return -errs;
690 }
691
692 static const struct refspec *check_pattern_match(const struct refspec *rs,
693                                                  int rs_nr,
694                                                  const struct ref *src)
695 {
696         int i;
697         for (i = 0; i < rs_nr; i++) {
698                 if (rs[i].pattern && !prefixcmp(src->name, rs[i].src))
699                         return rs + i;
700         }
701         return NULL;
702 }
703
704 /*
705  * Note. This is used only by "push"; refspec matching rules for
706  * push and fetch are subtly different, so do not try to reuse it
707  * without thinking.
708  */
709 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
710                int nr_refspec, const char **refspec, int flags)
711 {
712         struct refspec *rs =
713                 parse_ref_spec(nr_refspec, (const char **) refspec);
714         int send_all = flags & MATCH_REFS_ALL;
715         int send_mirror = flags & MATCH_REFS_MIRROR;
716
717         if (match_explicit_refs(src, dst, dst_tail, rs, nr_refspec))
718                 return -1;
719
720         /* pick the remainder */
721         for ( ; src; src = src->next) {
722                 struct ref *dst_peer;
723                 const struct refspec *pat = NULL;
724                 char *dst_name;
725                 if (src->peer_ref)
726                         continue;
727                 if (nr_refspec) {
728                         pat = check_pattern_match(rs, nr_refspec, src);
729                         if (!pat)
730                                 continue;
731                 }
732                 else if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
733                         /*
734                          * "matching refs"; traditionally we pushed everything
735                          * including refs outside refs/heads/ hierarchy, but
736                          * that does not make much sense these days.
737                          */
738                         continue;
739
740                 if (pat) {
741                         const char *dst_side = pat->dst ? pat->dst : pat->src;
742                         dst_name = xmalloc(strlen(dst_side) +
743                                            strlen(src->name) -
744                                            strlen(pat->src) + 2);
745                         strcpy(dst_name, dst_side);
746                         strcat(dst_name, src->name + strlen(pat->src));
747                 } else
748                         dst_name = xstrdup(src->name);
749                 dst_peer = find_ref_by_name(dst, dst_name);
750                 if (dst_peer && dst_peer->peer_ref)
751                         /* We're already sending something to this ref. */
752                         goto free_name;
753
754                 if (!dst_peer && !nr_refspec && !(send_all || send_mirror))
755                         /*
756                          * Remote doesn't have it, and we have no
757                          * explicit pattern, and we don't have
758                          * --all nor --mirror.
759                          */
760                         goto free_name;
761                 if (!dst_peer) {
762                         /* Create a new one and link it */
763                         dst_peer = make_linked_ref(dst_name, dst_tail);
764                         hashcpy(dst_peer->new_sha1, src->new_sha1);
765                 }
766                 dst_peer->peer_ref = src;
767                 if (pat)
768                         dst_peer->force = pat->force;
769         free_name:
770                 free(dst_name);
771         }
772         return 0;
773 }
774
775 struct branch *branch_get(const char *name)
776 {
777         struct branch *ret;
778
779         read_config();
780         if (!name || !*name || !strcmp(name, "HEAD"))
781                 ret = current_branch;
782         else
783                 ret = make_branch(name, 0);
784         if (ret && ret->remote_name) {
785                 ret->remote = remote_get(ret->remote_name);
786                 if (ret->merge_nr) {
787                         int i;
788                         ret->merge = xcalloc(sizeof(*ret->merge),
789                                              ret->merge_nr);
790                         for (i = 0; i < ret->merge_nr; i++) {
791                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
792                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
793                                 remote_find_tracking(ret->remote,
794                                                      ret->merge[i]);
795                         }
796                 }
797         }
798         return ret;
799 }
800
801 int branch_has_merge_config(struct branch *branch)
802 {
803         return branch && !!branch->merge;
804 }
805
806 int branch_merge_matches(struct branch *branch,
807                                  int i,
808                                  const char *refname)
809 {
810         if (!branch || i < 0 || i >= branch->merge_nr)
811                 return 0;
812         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
813 }
814
815 static struct ref *get_expanded_map(const struct ref *remote_refs,
816                                     const struct refspec *refspec)
817 {
818         const struct ref *ref;
819         struct ref *ret = NULL;
820         struct ref **tail = &ret;
821
822         int remote_prefix_len = strlen(refspec->src);
823         int local_prefix_len = strlen(refspec->dst);
824
825         for (ref = remote_refs; ref; ref = ref->next) {
826                 if (strchr(ref->name, '^'))
827                         continue; /* a dereference item */
828                 if (!prefixcmp(ref->name, refspec->src)) {
829                         const char *match;
830                         struct ref *cpy = copy_ref(ref);
831                         match = ref->name + remote_prefix_len;
832
833                         cpy->peer_ref = alloc_ref(local_prefix_len +
834                                                   strlen(match) + 1);
835                         sprintf(cpy->peer_ref->name, "%s%s",
836                                 refspec->dst, match);
837                         if (refspec->force)
838                                 cpy->peer_ref->force = 1;
839                         *tail = cpy;
840                         tail = &cpy->next;
841                 }
842         }
843
844         return ret;
845 }
846
847 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
848 {
849         const struct ref *ref;
850         for (ref = refs; ref; ref = ref->next) {
851                 if (refname_match(name, ref->name, ref_fetch_rules))
852                         return ref;
853         }
854         return NULL;
855 }
856
857 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
858 {
859         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
860
861         if (!ref)
862                 return NULL;
863
864         return copy_ref(ref);
865 }
866
867 static struct ref *get_local_ref(const char *name)
868 {
869         struct ref *ret;
870         if (!name)
871                 return NULL;
872
873         if (!prefixcmp(name, "refs/")) {
874                 ret = alloc_ref(strlen(name) + 1);
875                 strcpy(ret->name, name);
876                 return ret;
877         }
878
879         if (!prefixcmp(name, "heads/") ||
880             !prefixcmp(name, "tags/") ||
881             !prefixcmp(name, "remotes/")) {
882                 ret = alloc_ref(strlen(name) + 6);
883                 sprintf(ret->name, "refs/%s", name);
884                 return ret;
885         }
886
887         ret = alloc_ref(strlen(name) + 12);
888         sprintf(ret->name, "refs/heads/%s", name);
889         return ret;
890 }
891
892 int get_fetch_map(const struct ref *remote_refs,
893                   const struct refspec *refspec,
894                   struct ref ***tail,
895                   int missing_ok)
896 {
897         struct ref *ref_map, *rm;
898
899         if (refspec->pattern) {
900                 ref_map = get_expanded_map(remote_refs, refspec);
901         } else {
902                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
903
904                 ref_map = get_remote_ref(remote_refs, name);
905                 if (!missing_ok && !ref_map)
906                         die("Couldn't find remote ref %s", name);
907                 if (ref_map) {
908                         ref_map->peer_ref = get_local_ref(refspec->dst);
909                         if (ref_map->peer_ref && refspec->force)
910                                 ref_map->peer_ref->force = 1;
911                 }
912         }
913
914         for (rm = ref_map; rm; rm = rm->next) {
915                 if (rm->peer_ref && check_ref_format(rm->peer_ref->name + 5))
916                         die("* refusing to create funny ref '%s' locally",
917                             rm->peer_ref->name);
918         }
919
920         if (ref_map)
921                 tail_link_ref(ref_map, tail);
922
923         return 0;
924 }