t7800-difftool.sh: Simplify the --extcmd test
[git] / remote.c
1 #include "cache.h"
2 #include "remote.h"
3 #include "refs.h"
4 #include "commit.h"
5 #include "diff.h"
6 #include "revision.h"
7 #include "dir.h"
8 #include "tag.h"
9 #include "string-list.h"
10
11 static struct refspec s_tag_refspec = {
12         0,
13         1,
14         0,
15         "refs/tags/*",
16         "refs/tags/*"
17 };
18
19 const struct refspec *tag_refspec = &s_tag_refspec;
20
21 struct counted_string {
22         size_t len;
23         const char *s;
24 };
25 struct rewrite {
26         const char *base;
27         size_t baselen;
28         struct counted_string *instead_of;
29         int instead_of_nr;
30         int instead_of_alloc;
31 };
32 struct rewrites {
33         struct rewrite **rewrite;
34         int rewrite_alloc;
35         int rewrite_nr;
36 };
37
38 static struct remote **remotes;
39 static int remotes_alloc;
40 static int remotes_nr;
41
42 static struct branch **branches;
43 static int branches_alloc;
44 static int branches_nr;
45
46 static struct branch *current_branch;
47 static const char *default_remote_name;
48 static int explicit_default_remote_name;
49
50 static struct rewrites rewrites;
51 static struct rewrites rewrites_push;
52
53 #define BUF_SIZE (2048)
54 static char buffer[BUF_SIZE];
55
56 static const char *alias_url(const char *url, struct rewrites *r)
57 {
58         int i, j;
59         char *ret;
60         struct counted_string *longest;
61         int longest_i;
62
63         longest = NULL;
64         longest_i = -1;
65         for (i = 0; i < r->rewrite_nr; i++) {
66                 if (!r->rewrite[i])
67                         continue;
68                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
69                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
70                             (!longest ||
71                              longest->len < r->rewrite[i]->instead_of[j].len)) {
72                                 longest = &(r->rewrite[i]->instead_of[j]);
73                                 longest_i = i;
74                         }
75                 }
76         }
77         if (!longest)
78                 return url;
79
80         ret = xmalloc(r->rewrite[longest_i]->baselen +
81                      (strlen(url) - longest->len) + 1);
82         strcpy(ret, r->rewrite[longest_i]->base);
83         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
84         return ret;
85 }
86
87 static void add_push_refspec(struct remote *remote, const char *ref)
88 {
89         ALLOC_GROW(remote->push_refspec,
90                    remote->push_refspec_nr + 1,
91                    remote->push_refspec_alloc);
92         remote->push_refspec[remote->push_refspec_nr++] = ref;
93 }
94
95 static void add_fetch_refspec(struct remote *remote, const char *ref)
96 {
97         ALLOC_GROW(remote->fetch_refspec,
98                    remote->fetch_refspec_nr + 1,
99                    remote->fetch_refspec_alloc);
100         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
101 }
102
103 static void add_url(struct remote *remote, const char *url)
104 {
105         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
106         remote->url[remote->url_nr++] = url;
107 }
108
109 static void add_pushurl(struct remote *remote, const char *pushurl)
110 {
111         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
112         remote->pushurl[remote->pushurl_nr++] = pushurl;
113 }
114
115 static void add_pushurl_alias(struct remote *remote, const char *url)
116 {
117         const char *pushurl = alias_url(url, &rewrites_push);
118         if (pushurl != url)
119                 add_pushurl(remote, pushurl);
120 }
121
122 static void add_url_alias(struct remote *remote, const char *url)
123 {
124         add_url(remote, alias_url(url, &rewrites));
125         add_pushurl_alias(remote, url);
126 }
127
128 static struct remote *make_remote(const char *name, int len)
129 {
130         struct remote *ret;
131         int i;
132
133         for (i = 0; i < remotes_nr; i++) {
134                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
135                            !remotes[i]->name[len]) :
136                     !strcmp(name, remotes[i]->name))
137                         return remotes[i];
138         }
139
140         ret = xcalloc(1, sizeof(struct remote));
141         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
142         remotes[remotes_nr++] = ret;
143         if (len)
144                 ret->name = xstrndup(name, len);
145         else
146                 ret->name = xstrdup(name);
147         return ret;
148 }
149
150 static void add_merge(struct branch *branch, const char *name)
151 {
152         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
153                    branch->merge_alloc);
154         branch->merge_name[branch->merge_nr++] = name;
155 }
156
157 static struct branch *make_branch(const char *name, int len)
158 {
159         struct branch *ret;
160         int i;
161         char *refname;
162
163         for (i = 0; i < branches_nr; i++) {
164                 if (len ? (!strncmp(name, branches[i]->name, len) &&
165                            !branches[i]->name[len]) :
166                     !strcmp(name, branches[i]->name))
167                         return branches[i];
168         }
169
170         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
171         ret = xcalloc(1, sizeof(struct branch));
172         branches[branches_nr++] = ret;
173         if (len)
174                 ret->name = xstrndup(name, len);
175         else
176                 ret->name = xstrdup(name);
177         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
178         strcpy(refname, "refs/heads/");
179         strcpy(refname + strlen("refs/heads/"), ret->name);
180         ret->refname = refname;
181
182         return ret;
183 }
184
185 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
186 {
187         struct rewrite *ret;
188         int i;
189
190         for (i = 0; i < r->rewrite_nr; i++) {
191                 if (len
192                     ? (len == r->rewrite[i]->baselen &&
193                        !strncmp(base, r->rewrite[i]->base, len))
194                     : !strcmp(base, r->rewrite[i]->base))
195                         return r->rewrite[i];
196         }
197
198         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
199         ret = xcalloc(1, sizeof(struct rewrite));
200         r->rewrite[r->rewrite_nr++] = ret;
201         if (len) {
202                 ret->base = xstrndup(base, len);
203                 ret->baselen = len;
204         }
205         else {
206                 ret->base = xstrdup(base);
207                 ret->baselen = strlen(base);
208         }
209         return ret;
210 }
211
212 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
213 {
214         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
215         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
216         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
217         rewrite->instead_of_nr++;
218 }
219
220 static void read_remotes_file(struct remote *remote)
221 {
222         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
223
224         if (!f)
225                 return;
226         remote->origin = REMOTE_REMOTES;
227         while (fgets(buffer, BUF_SIZE, f)) {
228                 int value_list;
229                 char *s, *p;
230
231                 if (!prefixcmp(buffer, "URL:")) {
232                         value_list = 0;
233                         s = buffer + 4;
234                 } else if (!prefixcmp(buffer, "Push:")) {
235                         value_list = 1;
236                         s = buffer + 5;
237                 } else if (!prefixcmp(buffer, "Pull:")) {
238                         value_list = 2;
239                         s = buffer + 5;
240                 } else
241                         continue;
242
243                 while (isspace(*s))
244                         s++;
245                 if (!*s)
246                         continue;
247
248                 p = s + strlen(s);
249                 while (isspace(p[-1]))
250                         *--p = 0;
251
252                 switch (value_list) {
253                 case 0:
254                         add_url_alias(remote, xstrdup(s));
255                         break;
256                 case 1:
257                         add_push_refspec(remote, xstrdup(s));
258                         break;
259                 case 2:
260                         add_fetch_refspec(remote, xstrdup(s));
261                         break;
262                 }
263         }
264         fclose(f);
265 }
266
267 static void read_branches_file(struct remote *remote)
268 {
269         const char *slash = strchr(remote->name, '/');
270         char *frag;
271         struct strbuf branch = STRBUF_INIT;
272         int n = slash ? slash - remote->name : 1000;
273         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
274         char *s, *p;
275         int len;
276
277         if (!f)
278                 return;
279         s = fgets(buffer, BUF_SIZE, f);
280         fclose(f);
281         if (!s)
282                 return;
283         while (isspace(*s))
284                 s++;
285         if (!*s)
286                 return;
287         remote->origin = REMOTE_BRANCHES;
288         p = s + strlen(s);
289         while (isspace(p[-1]))
290                 *--p = 0;
291         len = p - s;
292         if (slash)
293                 len += strlen(slash);
294         p = xmalloc(len + 1);
295         strcpy(p, s);
296         if (slash)
297                 strcat(p, slash);
298
299         /*
300          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
301          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
302          * the partial URL obtained from the branches file plus
303          * "/netdev-2.6" and does not store it in any tracking ref.
304          * #branch specifier in the file is ignored.
305          *
306          * Otherwise, the branches file would have URL and optionally
307          * #branch specified.  The "master" (or specified) branch is
308          * fetched and stored in the local branch of the same name.
309          */
310         frag = strchr(p, '#');
311         if (frag) {
312                 *(frag++) = '\0';
313                 strbuf_addf(&branch, "refs/heads/%s", frag);
314         } else
315                 strbuf_addstr(&branch, "refs/heads/master");
316         if (!slash) {
317                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
318         } else {
319                 strbuf_reset(&branch);
320                 strbuf_addstr(&branch, "HEAD:");
321         }
322         add_url_alias(remote, p);
323         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
324         /*
325          * Cogito compatible push: push current HEAD to remote #branch
326          * (master if missing)
327          */
328         strbuf_init(&branch, 0);
329         strbuf_addstr(&branch, "HEAD");
330         if (frag)
331                 strbuf_addf(&branch, ":refs/heads/%s", frag);
332         else
333                 strbuf_addstr(&branch, ":refs/heads/master");
334         add_push_refspec(remote, strbuf_detach(&branch, NULL));
335         remote->fetch_tags = 1; /* always auto-follow */
336 }
337
338 static int handle_config(const char *key, const char *value, void *cb)
339 {
340         const char *name;
341         const char *subkey;
342         struct remote *remote;
343         struct branch *branch;
344         if (!prefixcmp(key, "branch.")) {
345                 name = key + 7;
346                 subkey = strrchr(name, '.');
347                 if (!subkey)
348                         return 0;
349                 branch = make_branch(name, subkey - name);
350                 if (!strcmp(subkey, ".remote")) {
351                         if (!value)
352                                 return config_error_nonbool(key);
353                         branch->remote_name = xstrdup(value);
354                         if (branch == current_branch) {
355                                 default_remote_name = branch->remote_name;
356                                 explicit_default_remote_name = 1;
357                         }
358                 } else if (!strcmp(subkey, ".merge")) {
359                         if (!value)
360                                 return config_error_nonbool(key);
361                         add_merge(branch, xstrdup(value));
362                 }
363                 return 0;
364         }
365         if (!prefixcmp(key, "url.")) {
366                 struct rewrite *rewrite;
367                 name = key + 4;
368                 subkey = strrchr(name, '.');
369                 if (!subkey)
370                         return 0;
371                 if (!strcmp(subkey, ".insteadof")) {
372                         rewrite = make_rewrite(&rewrites, name, subkey - name);
373                         if (!value)
374                                 return config_error_nonbool(key);
375                         add_instead_of(rewrite, xstrdup(value));
376                 } else if (!strcmp(subkey, ".pushinsteadof")) {
377                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
378                         if (!value)
379                                 return config_error_nonbool(key);
380                         add_instead_of(rewrite, xstrdup(value));
381                 }
382         }
383         if (prefixcmp(key,  "remote."))
384                 return 0;
385         name = key + 7;
386         if (*name == '/') {
387                 warning("Config remote shorthand cannot begin with '/': %s",
388                         name);
389                 return 0;
390         }
391         subkey = strrchr(name, '.');
392         if (!subkey)
393                 return 0;
394         remote = make_remote(name, subkey - name);
395         remote->origin = REMOTE_CONFIG;
396         if (!strcmp(subkey, ".mirror"))
397                 remote->mirror = git_config_bool(key, value);
398         else if (!strcmp(subkey, ".skipdefaultupdate"))
399                 remote->skip_default_update = git_config_bool(key, value);
400         else if (!strcmp(subkey, ".skipfetchall"))
401                 remote->skip_default_update = git_config_bool(key, value);
402         else if (!strcmp(subkey, ".url")) {
403                 const char *v;
404                 if (git_config_string(&v, key, value))
405                         return -1;
406                 add_url(remote, v);
407         } else if (!strcmp(subkey, ".pushurl")) {
408                 const char *v;
409                 if (git_config_string(&v, key, value))
410                         return -1;
411                 add_pushurl(remote, v);
412         } else if (!strcmp(subkey, ".push")) {
413                 const char *v;
414                 if (git_config_string(&v, key, value))
415                         return -1;
416                 add_push_refspec(remote, v);
417         } else if (!strcmp(subkey, ".fetch")) {
418                 const char *v;
419                 if (git_config_string(&v, key, value))
420                         return -1;
421                 add_fetch_refspec(remote, v);
422         } else if (!strcmp(subkey, ".receivepack")) {
423                 const char *v;
424                 if (git_config_string(&v, key, value))
425                         return -1;
426                 if (!remote->receivepack)
427                         remote->receivepack = v;
428                 else
429                         error("more than one receivepack given, using the first");
430         } else if (!strcmp(subkey, ".uploadpack")) {
431                 const char *v;
432                 if (git_config_string(&v, key, value))
433                         return -1;
434                 if (!remote->uploadpack)
435                         remote->uploadpack = v;
436                 else
437                         error("more than one uploadpack given, using the first");
438         } else if (!strcmp(subkey, ".tagopt")) {
439                 if (!strcmp(value, "--no-tags"))
440                         remote->fetch_tags = -1;
441         } else if (!strcmp(subkey, ".proxy")) {
442                 return git_config_string((const char **)&remote->http_proxy,
443                                          key, value);
444         }
445         return 0;
446 }
447
448 static void alias_all_urls(void)
449 {
450         int i, j;
451         for (i = 0; i < remotes_nr; i++) {
452                 int add_pushurl_aliases;
453                 if (!remotes[i])
454                         continue;
455                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
456                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
457                 }
458                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
459                 for (j = 0; j < remotes[i]->url_nr; j++) {
460                         if (add_pushurl_aliases)
461                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
462                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
463                 }
464         }
465 }
466
467 static void read_config(void)
468 {
469         unsigned char sha1[20];
470         const char *head_ref;
471         int flag;
472         if (default_remote_name) // did this already
473                 return;
474         default_remote_name = xstrdup("origin");
475         current_branch = NULL;
476         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
477         if (head_ref && (flag & REF_ISSYMREF) &&
478             !prefixcmp(head_ref, "refs/heads/")) {
479                 current_branch =
480                         make_branch(head_ref + strlen("refs/heads/"), 0);
481         }
482         git_config(handle_config, NULL);
483         alias_all_urls();
484 }
485
486 /*
487  * We need to make sure the tracking branches are well formed, but a
488  * wildcard refspec in "struct refspec" must have a trailing slash. We
489  * temporarily drop the trailing '/' while calling check_ref_format(),
490  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
491  * error return is Ok for a wildcard refspec.
492  */
493 static int verify_refname(char *name, int is_glob)
494 {
495         int result;
496
497         result = check_ref_format(name);
498         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
499                 result = CHECK_REF_FORMAT_OK;
500         return result;
501 }
502
503 /*
504  * This function frees a refspec array.
505  * Warning: code paths should be checked to ensure that the src
506  *          and dst pointers are always freeable pointers as well
507  *          as the refspec pointer itself.
508  */
509 static void free_refspecs(struct refspec *refspec, int nr_refspec)
510 {
511         int i;
512
513         if (!refspec)
514                 return;
515
516         for (i = 0; i < nr_refspec; i++) {
517                 free(refspec[i].src);
518                 free(refspec[i].dst);
519         }
520         free(refspec);
521 }
522
523 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
524 {
525         int i;
526         int st;
527         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
528
529         for (i = 0; i < nr_refspec; i++) {
530                 size_t llen;
531                 int is_glob;
532                 const char *lhs, *rhs;
533
534                 is_glob = 0;
535
536                 lhs = refspec[i];
537                 if (*lhs == '+') {
538                         rs[i].force = 1;
539                         lhs++;
540                 }
541
542                 rhs = strrchr(lhs, ':');
543
544                 /*
545                  * Before going on, special case ":" (or "+:") as a refspec
546                  * for matching refs.
547                  */
548                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
549                         rs[i].matching = 1;
550                         continue;
551                 }
552
553                 if (rhs) {
554                         size_t rlen = strlen(++rhs);
555                         is_glob = (1 <= rlen && strchr(rhs, '*'));
556                         rs[i].dst = xstrndup(rhs, rlen);
557                 }
558
559                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
560                 if (1 <= llen && memchr(lhs, '*', llen)) {
561                         if ((rhs && !is_glob) || (!rhs && fetch))
562                                 goto invalid;
563                         is_glob = 1;
564                 } else if (rhs && is_glob) {
565                         goto invalid;
566                 }
567
568                 rs[i].pattern = is_glob;
569                 rs[i].src = xstrndup(lhs, llen);
570
571                 if (fetch) {
572                         /*
573                          * LHS
574                          * - empty is allowed; it means HEAD.
575                          * - otherwise it must be a valid looking ref.
576                          */
577                         if (!*rs[i].src)
578                                 ; /* empty is ok */
579                         else {
580                                 st = verify_refname(rs[i].src, is_glob);
581                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
582                                         goto invalid;
583                         }
584                         /*
585                          * RHS
586                          * - missing is ok, and is same as empty.
587                          * - empty is ok; it means not to store.
588                          * - otherwise it must be a valid looking ref.
589                          */
590                         if (!rs[i].dst) {
591                                 ; /* ok */
592                         } else if (!*rs[i].dst) {
593                                 ; /* ok */
594                         } else {
595                                 st = verify_refname(rs[i].dst, is_glob);
596                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
597                                         goto invalid;
598                         }
599                 } else {
600                         /*
601                          * LHS
602                          * - empty is allowed; it means delete.
603                          * - when wildcarded, it must be a valid looking ref.
604                          * - otherwise, it must be an extended SHA-1, but
605                          *   there is no existing way to validate this.
606                          */
607                         if (!*rs[i].src)
608                                 ; /* empty is ok */
609                         else if (is_glob) {
610                                 st = verify_refname(rs[i].src, is_glob);
611                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
612                                         goto invalid;
613                         }
614                         else
615                                 ; /* anything goes, for now */
616                         /*
617                          * RHS
618                          * - missing is allowed, but LHS then must be a
619                          *   valid looking ref.
620                          * - empty is not allowed.
621                          * - otherwise it must be a valid looking ref.
622                          */
623                         if (!rs[i].dst) {
624                                 st = verify_refname(rs[i].src, is_glob);
625                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
626                                         goto invalid;
627                         } else if (!*rs[i].dst) {
628                                 goto invalid;
629                         } else {
630                                 st = verify_refname(rs[i].dst, is_glob);
631                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
632                                         goto invalid;
633                         }
634                 }
635         }
636         return rs;
637
638  invalid:
639         if (verify) {
640                 /*
641                  * nr_refspec must be greater than zero and i must be valid
642                  * since it is only possible to reach this point from within
643                  * the for loop above.
644                  */
645                 free_refspecs(rs, i+1);
646                 return NULL;
647         }
648         die("Invalid refspec '%s'", refspec[i]);
649 }
650
651 int valid_fetch_refspec(const char *fetch_refspec_str)
652 {
653         const char *fetch_refspec[] = { fetch_refspec_str };
654         struct refspec *refspec;
655
656         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
657         free_refspecs(refspec, 1);
658         return !!refspec;
659 }
660
661 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
662 {
663         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
664 }
665
666 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
667 {
668         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
669 }
670
671 static int valid_remote_nick(const char *name)
672 {
673         if (!name[0] || is_dot_or_dotdot(name))
674                 return 0;
675         return !strchr(name, '/'); /* no slash */
676 }
677
678 struct remote *remote_get(const char *name)
679 {
680         struct remote *ret;
681         int name_given = 0;
682
683         read_config();
684         if (name)
685                 name_given = 1;
686         else {
687                 name = default_remote_name;
688                 name_given = explicit_default_remote_name;
689         }
690
691         ret = make_remote(name, 0);
692         if (valid_remote_nick(name)) {
693                 if (!ret->url)
694                         read_remotes_file(ret);
695                 if (!ret->url)
696                         read_branches_file(ret);
697         }
698         if (name_given && !ret->url)
699                 add_url_alias(ret, name);
700         if (!ret->url)
701                 return NULL;
702         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
703         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
704         return ret;
705 }
706
707 int remote_is_configured(const char *name)
708 {
709         int i;
710         read_config();
711
712         for (i = 0; i < remotes_nr; i++)
713                 if (!strcmp(name, remotes[i]->name))
714                         return 1;
715         return 0;
716 }
717
718 int for_each_remote(each_remote_fn fn, void *priv)
719 {
720         int i, result = 0;
721         read_config();
722         for (i = 0; i < remotes_nr && !result; i++) {
723                 struct remote *r = remotes[i];
724                 if (!r)
725                         continue;
726                 if (!r->fetch)
727                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
728                                                        r->fetch_refspec);
729                 if (!r->push)
730                         r->push = parse_push_refspec(r->push_refspec_nr,
731                                                      r->push_refspec);
732                 result = fn(r, priv);
733         }
734         return result;
735 }
736
737 void ref_remove_duplicates(struct ref *ref_map)
738 {
739         struct string_list refs = { NULL, 0, 0, 0 };
740         struct string_list_item *item = NULL;
741         struct ref *prev = NULL, *next = NULL;
742         for (; ref_map; prev = ref_map, ref_map = next) {
743                 next = ref_map->next;
744                 if (!ref_map->peer_ref)
745                         continue;
746
747                 item = string_list_lookup(ref_map->peer_ref->name, &refs);
748                 if (item) {
749                         if (strcmp(((struct ref *)item->util)->name,
750                                    ref_map->name))
751                                 die("%s tracks both %s and %s",
752                                     ref_map->peer_ref->name,
753                                     ((struct ref *)item->util)->name,
754                                     ref_map->name);
755                         prev->next = ref_map->next;
756                         free(ref_map->peer_ref);
757                         free(ref_map);
758                         ref_map = prev; /* skip this; we freed it */
759                         continue;
760                 }
761
762                 item = string_list_insert(ref_map->peer_ref->name, &refs);
763                 item->util = ref_map;
764         }
765         string_list_clear(&refs, 0);
766 }
767
768 int remote_has_url(struct remote *remote, const char *url)
769 {
770         int i;
771         for (i = 0; i < remote->url_nr; i++) {
772                 if (!strcmp(remote->url[i], url))
773                         return 1;
774         }
775         return 0;
776 }
777
778 static int match_name_with_pattern(const char *key, const char *name,
779                                    const char *value, char **result)
780 {
781         const char *kstar = strchr(key, '*');
782         size_t klen;
783         size_t ksuffixlen;
784         size_t namelen;
785         int ret;
786         if (!kstar)
787                 die("Key '%s' of pattern had no '*'", key);
788         klen = kstar - key;
789         ksuffixlen = strlen(kstar + 1);
790         namelen = strlen(name);
791         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
792                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
793         if (ret && value) {
794                 const char *vstar = strchr(value, '*');
795                 size_t vlen;
796                 size_t vsuffixlen;
797                 if (!vstar)
798                         die("Value '%s' of pattern has no '*'", value);
799                 vlen = vstar - value;
800                 vsuffixlen = strlen(vstar + 1);
801                 *result = xmalloc(vlen + vsuffixlen +
802                                   strlen(name) -
803                                   klen - ksuffixlen + 1);
804                 strncpy(*result, value, vlen);
805                 strncpy(*result + vlen,
806                         name + klen, namelen - klen - ksuffixlen);
807                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
808                        vstar + 1);
809         }
810         return ret;
811 }
812
813 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
814 {
815         int find_src = refspec->src == NULL;
816         char *needle, **result;
817         int i;
818
819         if (find_src) {
820                 if (!refspec->dst)
821                         return error("find_tracking: need either src or dst");
822                 needle = refspec->dst;
823                 result = &refspec->src;
824         } else {
825                 needle = refspec->src;
826                 result = &refspec->dst;
827         }
828
829         for (i = 0; i < remote->fetch_refspec_nr; i++) {
830                 struct refspec *fetch = &remote->fetch[i];
831                 const char *key = find_src ? fetch->dst : fetch->src;
832                 const char *value = find_src ? fetch->src : fetch->dst;
833                 if (!fetch->dst)
834                         continue;
835                 if (fetch->pattern) {
836                         if (match_name_with_pattern(key, needle, value, result)) {
837                                 refspec->force = fetch->force;
838                                 return 0;
839                         }
840                 } else if (!strcmp(needle, key)) {
841                         *result = xstrdup(value);
842                         refspec->force = fetch->force;
843                         return 0;
844                 }
845         }
846         return -1;
847 }
848
849 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
850                 const char *name)
851 {
852         size_t len = strlen(name);
853         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
854         memcpy(ref->name, prefix, prefixlen);
855         memcpy(ref->name + prefixlen, name, len);
856         return ref;
857 }
858
859 struct ref *alloc_ref(const char *name)
860 {
861         return alloc_ref_with_prefix("", 0, name);
862 }
863
864 static struct ref *copy_ref(const struct ref *ref)
865 {
866         struct ref *cpy;
867         size_t len;
868         if (!ref)
869                 return NULL;
870         len = strlen(ref->name);
871         cpy = xmalloc(sizeof(struct ref) + len + 1);
872         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
873         cpy->next = NULL;
874         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
875         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
876         cpy->peer_ref = copy_ref(ref->peer_ref);
877         return cpy;
878 }
879
880 struct ref *copy_ref_list(const struct ref *ref)
881 {
882         struct ref *ret = NULL;
883         struct ref **tail = &ret;
884         while (ref) {
885                 *tail = copy_ref(ref);
886                 ref = ref->next;
887                 tail = &((*tail)->next);
888         }
889         return ret;
890 }
891
892 static void free_ref(struct ref *ref)
893 {
894         if (!ref)
895                 return;
896         free_ref(ref->peer_ref);
897         free(ref->remote_status);
898         free(ref->symref);
899         free(ref);
900 }
901
902 void free_refs(struct ref *ref)
903 {
904         struct ref *next;
905         while (ref) {
906                 next = ref->next;
907                 free_ref(ref);
908                 ref = next;
909         }
910 }
911
912 static int count_refspec_match(const char *pattern,
913                                struct ref *refs,
914                                struct ref **matched_ref)
915 {
916         int patlen = strlen(pattern);
917         struct ref *matched_weak = NULL;
918         struct ref *matched = NULL;
919         int weak_match = 0;
920         int match = 0;
921
922         for (weak_match = match = 0; refs; refs = refs->next) {
923                 char *name = refs->name;
924                 int namelen = strlen(name);
925
926                 if (!refname_match(pattern, name, ref_rev_parse_rules))
927                         continue;
928
929                 /* A match is "weak" if it is with refs outside
930                  * heads or tags, and did not specify the pattern
931                  * in full (e.g. "refs/remotes/origin/master") or at
932                  * least from the toplevel (e.g. "remotes/origin/master");
933                  * otherwise "git push $URL master" would result in
934                  * ambiguity between remotes/origin/master and heads/master
935                  * at the remote site.
936                  */
937                 if (namelen != patlen &&
938                     patlen != namelen - 5 &&
939                     prefixcmp(name, "refs/heads/") &&
940                     prefixcmp(name, "refs/tags/")) {
941                         /* We want to catch the case where only weak
942                          * matches are found and there are multiple
943                          * matches, and where more than one strong
944                          * matches are found, as ambiguous.  One
945                          * strong match with zero or more weak matches
946                          * are acceptable as a unique match.
947                          */
948                         matched_weak = refs;
949                         weak_match++;
950                 }
951                 else {
952                         matched = refs;
953                         match++;
954                 }
955         }
956         if (!matched) {
957                 *matched_ref = matched_weak;
958                 return weak_match;
959         }
960         else {
961                 *matched_ref = matched;
962                 return match;
963         }
964 }
965
966 static void tail_link_ref(struct ref *ref, struct ref ***tail)
967 {
968         **tail = ref;
969         while (ref->next)
970                 ref = ref->next;
971         *tail = &ref->next;
972 }
973
974 static struct ref *try_explicit_object_name(const char *name)
975 {
976         unsigned char sha1[20];
977         struct ref *ref;
978
979         if (!*name) {
980                 ref = alloc_ref("(delete)");
981                 hashclr(ref->new_sha1);
982                 return ref;
983         }
984         if (get_sha1(name, sha1))
985                 return NULL;
986         ref = alloc_ref(name);
987         hashcpy(ref->new_sha1, sha1);
988         return ref;
989 }
990
991 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
992 {
993         struct ref *ret = alloc_ref(name);
994         tail_link_ref(ret, tail);
995         return ret;
996 }
997
998 static char *guess_ref(const char *name, struct ref *peer)
999 {
1000         struct strbuf buf = STRBUF_INIT;
1001         unsigned char sha1[20];
1002
1003         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1004         if (!r)
1005                 return NULL;
1006
1007         if (!prefixcmp(r, "refs/heads/"))
1008                 strbuf_addstr(&buf, "refs/heads/");
1009         else if (!prefixcmp(r, "refs/tags/"))
1010                 strbuf_addstr(&buf, "refs/tags/");
1011         else
1012                 return NULL;
1013
1014         strbuf_addstr(&buf, name);
1015         return strbuf_detach(&buf, NULL);
1016 }
1017
1018 static int match_explicit(struct ref *src, struct ref *dst,
1019                           struct ref ***dst_tail,
1020                           struct refspec *rs)
1021 {
1022         struct ref *matched_src, *matched_dst;
1023         int copy_src;
1024
1025         const char *dst_value = rs->dst;
1026         char *dst_guess;
1027
1028         if (rs->pattern || rs->matching)
1029                 return 0;
1030
1031         matched_src = matched_dst = NULL;
1032         switch (count_refspec_match(rs->src, src, &matched_src)) {
1033         case 1:
1034                 copy_src = 1;
1035                 break;
1036         case 0:
1037                 /* The source could be in the get_sha1() format
1038                  * not a reference name.  :refs/other is a
1039                  * way to delete 'other' ref at the remote end.
1040                  */
1041                 matched_src = try_explicit_object_name(rs->src);
1042                 if (!matched_src)
1043                         return error("src refspec %s does not match any.", rs->src);
1044                 copy_src = 0;
1045                 break;
1046         default:
1047                 return error("src refspec %s matches more than one.", rs->src);
1048         }
1049
1050         if (!dst_value) {
1051                 unsigned char sha1[20];
1052                 int flag;
1053
1054                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1055                 if (!dst_value ||
1056                     ((flag & REF_ISSYMREF) &&
1057                      prefixcmp(dst_value, "refs/heads/")))
1058                         die("%s cannot be resolved to branch.",
1059                             matched_src->name);
1060         }
1061
1062         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1063         case 1:
1064                 break;
1065         case 0:
1066                 if (!memcmp(dst_value, "refs/", 5))
1067                         matched_dst = make_linked_ref(dst_value, dst_tail);
1068                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1069                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1070                 else
1071                         error("unable to push to unqualified destination: %s\n"
1072                               "The destination refspec neither matches an "
1073                               "existing ref on the remote nor\n"
1074                               "begins with refs/, and we are unable to "
1075                               "guess a prefix based on the source ref.",
1076                               dst_value);
1077                 break;
1078         default:
1079                 matched_dst = NULL;
1080                 error("dst refspec %s matches more than one.",
1081                       dst_value);
1082                 break;
1083         }
1084         if (!matched_dst)
1085                 return -1;
1086         if (matched_dst->peer_ref)
1087                 return error("dst ref %s receives from more than one src.",
1088                       matched_dst->name);
1089         else {
1090                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1091                 matched_dst->force = rs->force;
1092         }
1093         return 0;
1094 }
1095
1096 static int match_explicit_refs(struct ref *src, struct ref *dst,
1097                                struct ref ***dst_tail, struct refspec *rs,
1098                                int rs_nr)
1099 {
1100         int i, errs;
1101         for (i = errs = 0; i < rs_nr; i++)
1102                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1103         return errs;
1104 }
1105
1106 static const struct refspec *check_pattern_match(const struct refspec *rs,
1107                                                  int rs_nr,
1108                                                  const struct ref *src)
1109 {
1110         int i;
1111         int matching_refs = -1;
1112         for (i = 0; i < rs_nr; i++) {
1113                 if (rs[i].matching &&
1114                     (matching_refs == -1 || rs[i].force)) {
1115                         matching_refs = i;
1116                         continue;
1117                 }
1118
1119                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1120                                                              NULL, NULL))
1121                         return rs + i;
1122         }
1123         if (matching_refs != -1)
1124                 return rs + matching_refs;
1125         else
1126                 return NULL;
1127 }
1128
1129 static struct ref **tail_ref(struct ref **head)
1130 {
1131         struct ref **tail = head;
1132         while (*tail)
1133                 tail = &((*tail)->next);
1134         return tail;
1135 }
1136
1137 /*
1138  * Note. This is used only by "push"; refspec matching rules for
1139  * push and fetch are subtly different, so do not try to reuse it
1140  * without thinking.
1141  */
1142 int match_refs(struct ref *src, struct ref **dst,
1143                int nr_refspec, const char **refspec, int flags)
1144 {
1145         struct refspec *rs;
1146         int send_all = flags & MATCH_REFS_ALL;
1147         int send_mirror = flags & MATCH_REFS_MIRROR;
1148         int errs;
1149         static const char *default_refspec[] = { ":", NULL };
1150         struct ref **dst_tail = tail_ref(dst);
1151
1152         if (!nr_refspec) {
1153                 nr_refspec = 1;
1154                 refspec = default_refspec;
1155         }
1156         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1157         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1158
1159         /* pick the remainder */
1160         for ( ; src; src = src->next) {
1161                 struct ref *dst_peer;
1162                 const struct refspec *pat = NULL;
1163                 char *dst_name;
1164                 if (src->peer_ref)
1165                         continue;
1166
1167                 pat = check_pattern_match(rs, nr_refspec, src);
1168                 if (!pat)
1169                         continue;
1170
1171                 if (pat->matching) {
1172                         /*
1173                          * "matching refs"; traditionally we pushed everything
1174                          * including refs outside refs/heads/ hierarchy, but
1175                          * that does not make much sense these days.
1176                          */
1177                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1178                                 continue;
1179                         dst_name = xstrdup(src->name);
1180
1181                 } else {
1182                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1183                         if (!match_name_with_pattern(pat->src, src->name,
1184                                                      dst_side, &dst_name))
1185                                 die("Didn't think it matches any more");
1186                 }
1187                 dst_peer = find_ref_by_name(*dst, dst_name);
1188                 if (dst_peer) {
1189                         if (dst_peer->peer_ref)
1190                                 /* We're already sending something to this ref. */
1191                                 goto free_name;
1192
1193                 } else {
1194                         if (pat->matching && !(send_all || send_mirror))
1195                                 /*
1196                                  * Remote doesn't have it, and we have no
1197                                  * explicit pattern, and we don't have
1198                                  * --all nor --mirror.
1199                                  */
1200                                 goto free_name;
1201
1202                         /* Create a new one and link it */
1203                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1204                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1205                 }
1206                 dst_peer->peer_ref = copy_ref(src);
1207                 dst_peer->force = pat->force;
1208         free_name:
1209                 free(dst_name);
1210         }
1211         if (errs)
1212                 return -1;
1213         return 0;
1214 }
1215
1216 struct branch *branch_get(const char *name)
1217 {
1218         struct branch *ret;
1219
1220         read_config();
1221         if (!name || !*name || !strcmp(name, "HEAD"))
1222                 ret = current_branch;
1223         else
1224                 ret = make_branch(name, 0);
1225         if (ret && ret->remote_name) {
1226                 ret->remote = remote_get(ret->remote_name);
1227                 if (ret->merge_nr) {
1228                         int i;
1229                         ret->merge = xcalloc(sizeof(*ret->merge),
1230                                              ret->merge_nr);
1231                         for (i = 0; i < ret->merge_nr; i++) {
1232                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1233                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1234                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1235                                     && !strcmp(ret->remote_name, "."))
1236                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1237                         }
1238                 }
1239         }
1240         return ret;
1241 }
1242
1243 int branch_has_merge_config(struct branch *branch)
1244 {
1245         return branch && !!branch->merge;
1246 }
1247
1248 int branch_merge_matches(struct branch *branch,
1249                                  int i,
1250                                  const char *refname)
1251 {
1252         if (!branch || i < 0 || i >= branch->merge_nr)
1253                 return 0;
1254         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1255 }
1256
1257 static struct ref *get_expanded_map(const struct ref *remote_refs,
1258                                     const struct refspec *refspec)
1259 {
1260         const struct ref *ref;
1261         struct ref *ret = NULL;
1262         struct ref **tail = &ret;
1263
1264         char *expn_name;
1265
1266         for (ref = remote_refs; ref; ref = ref->next) {
1267                 if (strchr(ref->name, '^'))
1268                         continue; /* a dereference item */
1269                 if (match_name_with_pattern(refspec->src, ref->name,
1270                                             refspec->dst, &expn_name)) {
1271                         struct ref *cpy = copy_ref(ref);
1272
1273                         cpy->peer_ref = alloc_ref(expn_name);
1274                         free(expn_name);
1275                         if (refspec->force)
1276                                 cpy->peer_ref->force = 1;
1277                         *tail = cpy;
1278                         tail = &cpy->next;
1279                 }
1280         }
1281
1282         return ret;
1283 }
1284
1285 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1286 {
1287         const struct ref *ref;
1288         for (ref = refs; ref; ref = ref->next) {
1289                 if (refname_match(name, ref->name, ref_fetch_rules))
1290                         return ref;
1291         }
1292         return NULL;
1293 }
1294
1295 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1296 {
1297         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1298
1299         if (!ref)
1300                 return NULL;
1301
1302         return copy_ref(ref);
1303 }
1304
1305 static struct ref *get_local_ref(const char *name)
1306 {
1307         if (!name || name[0] == '\0')
1308                 return NULL;
1309
1310         if (!prefixcmp(name, "refs/"))
1311                 return alloc_ref(name);
1312
1313         if (!prefixcmp(name, "heads/") ||
1314             !prefixcmp(name, "tags/") ||
1315             !prefixcmp(name, "remotes/"))
1316                 return alloc_ref_with_prefix("refs/", 5, name);
1317
1318         return alloc_ref_with_prefix("refs/heads/", 11, name);
1319 }
1320
1321 int get_fetch_map(const struct ref *remote_refs,
1322                   const struct refspec *refspec,
1323                   struct ref ***tail,
1324                   int missing_ok)
1325 {
1326         struct ref *ref_map, **rmp;
1327
1328         if (refspec->pattern) {
1329                 ref_map = get_expanded_map(remote_refs, refspec);
1330         } else {
1331                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1332
1333                 ref_map = get_remote_ref(remote_refs, name);
1334                 if (!missing_ok && !ref_map)
1335                         die("Couldn't find remote ref %s", name);
1336                 if (ref_map) {
1337                         ref_map->peer_ref = get_local_ref(refspec->dst);
1338                         if (ref_map->peer_ref && refspec->force)
1339                                 ref_map->peer_ref->force = 1;
1340                 }
1341         }
1342
1343         for (rmp = &ref_map; *rmp; ) {
1344                 if ((*rmp)->peer_ref) {
1345                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1346                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1347                                 struct ref *ignore = *rmp;
1348                                 error("* Ignoring funny ref '%s' locally",
1349                                       (*rmp)->peer_ref->name);
1350                                 *rmp = (*rmp)->next;
1351                                 free(ignore->peer_ref);
1352                                 free(ignore);
1353                                 continue;
1354                         }
1355                 }
1356                 rmp = &((*rmp)->next);
1357         }
1358
1359         if (ref_map)
1360                 tail_link_ref(ref_map, tail);
1361
1362         return 0;
1363 }
1364
1365 int resolve_remote_symref(struct ref *ref, struct ref *list)
1366 {
1367         if (!ref->symref)
1368                 return 0;
1369         for (; list; list = list->next)
1370                 if (!strcmp(ref->symref, list->name)) {
1371                         hashcpy(ref->old_sha1, list->old_sha1);
1372                         return 0;
1373                 }
1374         return 1;
1375 }
1376
1377 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1378 {
1379         while (list) {
1380                 struct commit_list *temp = list;
1381                 temp->item->object.flags &= ~mark;
1382                 list = temp->next;
1383                 free(temp);
1384         }
1385 }
1386
1387 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1388 {
1389         struct object *o;
1390         struct commit *old, *new;
1391         struct commit_list *list, *used;
1392         int found = 0;
1393
1394         /* Both new and old must be commit-ish and new is descendant of
1395          * old.  Otherwise we require --force.
1396          */
1397         o = deref_tag(parse_object(old_sha1), NULL, 0);
1398         if (!o || o->type != OBJ_COMMIT)
1399                 return 0;
1400         old = (struct commit *) o;
1401
1402         o = deref_tag(parse_object(new_sha1), NULL, 0);
1403         if (!o || o->type != OBJ_COMMIT)
1404                 return 0;
1405         new = (struct commit *) o;
1406
1407         if (parse_commit(new) < 0)
1408                 return 0;
1409
1410         used = list = NULL;
1411         commit_list_insert(new, &list);
1412         while (list) {
1413                 new = pop_most_recent_commit(&list, TMP_MARK);
1414                 commit_list_insert(new, &used);
1415                 if (new == old) {
1416                         found = 1;
1417                         break;
1418                 }
1419         }
1420         unmark_and_free(list, TMP_MARK);
1421         unmark_and_free(used, TMP_MARK);
1422         return found;
1423 }
1424
1425 /*
1426  * Return true if there is anything to report, otherwise false.
1427  */
1428 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1429 {
1430         unsigned char sha1[20];
1431         struct commit *ours, *theirs;
1432         char symmetric[84];
1433         struct rev_info revs;
1434         const char *rev_argv[10], *base;
1435         int rev_argc;
1436
1437         /*
1438          * Nothing to report unless we are marked to build on top of
1439          * somebody else.
1440          */
1441         if (!branch ||
1442             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1443                 return 0;
1444
1445         /*
1446          * If what we used to build on no longer exists, there is
1447          * nothing to report.
1448          */
1449         base = branch->merge[0]->dst;
1450         if (!resolve_ref(base, sha1, 1, NULL))
1451                 return 0;
1452         theirs = lookup_commit_reference(sha1);
1453         if (!theirs)
1454                 return 0;
1455
1456         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1457                 return 0;
1458         ours = lookup_commit_reference(sha1);
1459         if (!ours)
1460                 return 0;
1461
1462         /* are we the same? */
1463         if (theirs == ours)
1464                 return 0;
1465
1466         /* Run "rev-list --left-right ours...theirs" internally... */
1467         rev_argc = 0;
1468         rev_argv[rev_argc++] = NULL;
1469         rev_argv[rev_argc++] = "--left-right";
1470         rev_argv[rev_argc++] = symmetric;
1471         rev_argv[rev_argc++] = "--";
1472         rev_argv[rev_argc] = NULL;
1473
1474         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1475         strcpy(symmetric + 40, "...");
1476         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1477
1478         init_revisions(&revs, NULL);
1479         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1480         prepare_revision_walk(&revs);
1481
1482         /* ... and count the commits on each side. */
1483         *num_ours = 0;
1484         *num_theirs = 0;
1485         while (1) {
1486                 struct commit *c = get_revision(&revs);
1487                 if (!c)
1488                         break;
1489                 if (c->object.flags & SYMMETRIC_LEFT)
1490                         (*num_ours)++;
1491                 else
1492                         (*num_theirs)++;
1493         }
1494
1495         /* clear object flags smudged by the above traversal */
1496         clear_commit_marks(ours, ALL_REV_FLAGS);
1497         clear_commit_marks(theirs, ALL_REV_FLAGS);
1498         return 1;
1499 }
1500
1501 /*
1502  * Return true when there is anything to report, otherwise false.
1503  */
1504 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1505 {
1506         int num_ours, num_theirs;
1507         const char *base;
1508
1509         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1510                 return 0;
1511
1512         base = branch->merge[0]->dst;
1513         base = shorten_unambiguous_ref(base, 0);
1514         if (!num_theirs)
1515                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1516                             "by %d commit%s.\n",
1517                             base, num_ours, (num_ours == 1) ? "" : "s");
1518         else if (!num_ours)
1519                 strbuf_addf(sb, "Your branch is behind '%s' "
1520                             "by %d commit%s, "
1521                             "and can be fast-forwarded.\n",
1522                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1523         else
1524                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1525                             "and have %d and %d different commit(s) each, "
1526                             "respectively.\n",
1527                             base, num_ours, num_theirs);
1528         return 1;
1529 }
1530
1531 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1532 {
1533         struct ref ***local_tail = cb_data;
1534         struct ref *ref;
1535         int len;
1536
1537         /* we already know it starts with refs/ to get here */
1538         if (check_ref_format(refname + 5))
1539                 return 0;
1540
1541         len = strlen(refname) + 1;
1542         ref = xcalloc(1, sizeof(*ref) + len);
1543         hashcpy(ref->new_sha1, sha1);
1544         memcpy(ref->name, refname, len);
1545         **local_tail = ref;
1546         *local_tail = &ref->next;
1547         return 0;
1548 }
1549
1550 struct ref *get_local_heads(void)
1551 {
1552         struct ref *local_refs = NULL, **local_tail = &local_refs;
1553         for_each_ref(one_local_ref, &local_tail);
1554         return local_refs;
1555 }
1556
1557 struct ref *guess_remote_head(const struct ref *head,
1558                               const struct ref *refs,
1559                               int all)
1560 {
1561         const struct ref *r;
1562         struct ref *list = NULL;
1563         struct ref **tail = &list;
1564
1565         if (!head)
1566                 return NULL;
1567
1568         /*
1569          * Some transports support directly peeking at
1570          * where HEAD points; if that is the case, then
1571          * we don't have to guess.
1572          */
1573         if (head->symref)
1574                 return copy_ref(find_ref_by_name(refs, head->symref));
1575
1576         /* If refs/heads/master could be right, it is. */
1577         if (!all) {
1578                 r = find_ref_by_name(refs, "refs/heads/master");
1579                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1580                         return copy_ref(r);
1581         }
1582
1583         /* Look for another ref that points there */
1584         for (r = refs; r; r = r->next) {
1585                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1586                         *tail = copy_ref(r);
1587                         tail = &((*tail)->next);
1588                         if (!all)
1589                                 break;
1590                 }
1591         }
1592
1593         return list;
1594 }
1595
1596 struct stale_heads_info {
1597         struct remote *remote;
1598         struct string_list *ref_names;
1599         struct ref **stale_refs_tail;
1600 };
1601
1602 static int get_stale_heads_cb(const char *refname,
1603         const unsigned char *sha1, int flags, void *cb_data)
1604 {
1605         struct stale_heads_info *info = cb_data;
1606         struct refspec refspec;
1607         memset(&refspec, 0, sizeof(refspec));
1608         refspec.dst = (char *)refname;
1609         if (!remote_find_tracking(info->remote, &refspec)) {
1610                 if (!((flags & REF_ISSYMREF) ||
1611                     string_list_has_string(info->ref_names, refspec.src))) {
1612                         struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1613                         hashcpy(ref->new_sha1, sha1);
1614                 }
1615         }
1616         return 0;
1617 }
1618
1619 struct ref *get_stale_heads(struct remote *remote, struct ref *fetch_map)
1620 {
1621         struct ref *ref, *stale_refs = NULL;
1622         struct string_list ref_names = { NULL, 0, 0, 0 };
1623         struct stale_heads_info info;
1624         info.remote = remote;
1625         info.ref_names = &ref_names;
1626         info.stale_refs_tail = &stale_refs;
1627         for (ref = fetch_map; ref; ref = ref->next)
1628                 string_list_append(ref->name, &ref_names);
1629         sort_string_list(&ref_names);
1630         for_each_ref(get_stale_heads_cb, &info);
1631         string_list_clear(&ref_names, 0);
1632         return stale_refs;
1633 }