Merge branch 'maint'
[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 int valid_remote(const struct remote *remote)
57 {
58         return (!!remote->url) || (!!remote->foreign_vcs);
59 }
60
61 static const char *alias_url(const char *url, struct rewrites *r)
62 {
63         int i, j;
64         char *ret;
65         struct counted_string *longest;
66         int longest_i;
67
68         longest = NULL;
69         longest_i = -1;
70         for (i = 0; i < r->rewrite_nr; i++) {
71                 if (!r->rewrite[i])
72                         continue;
73                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
74                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
75                             (!longest ||
76                              longest->len < r->rewrite[i]->instead_of[j].len)) {
77                                 longest = &(r->rewrite[i]->instead_of[j]);
78                                 longest_i = i;
79                         }
80                 }
81         }
82         if (!longest)
83                 return url;
84
85         ret = xmalloc(r->rewrite[longest_i]->baselen +
86                      (strlen(url) - longest->len) + 1);
87         strcpy(ret, r->rewrite[longest_i]->base);
88         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
89         return ret;
90 }
91
92 static void add_push_refspec(struct remote *remote, const char *ref)
93 {
94         ALLOC_GROW(remote->push_refspec,
95                    remote->push_refspec_nr + 1,
96                    remote->push_refspec_alloc);
97         remote->push_refspec[remote->push_refspec_nr++] = ref;
98 }
99
100 static void add_fetch_refspec(struct remote *remote, const char *ref)
101 {
102         ALLOC_GROW(remote->fetch_refspec,
103                    remote->fetch_refspec_nr + 1,
104                    remote->fetch_refspec_alloc);
105         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
106 }
107
108 static void add_url(struct remote *remote, const char *url)
109 {
110         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
111         remote->url[remote->url_nr++] = url;
112 }
113
114 static void add_pushurl(struct remote *remote, const char *pushurl)
115 {
116         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
117         remote->pushurl[remote->pushurl_nr++] = pushurl;
118 }
119
120 static void add_pushurl_alias(struct remote *remote, const char *url)
121 {
122         const char *pushurl = alias_url(url, &rewrites_push);
123         if (pushurl != url)
124                 add_pushurl(remote, pushurl);
125 }
126
127 static void add_url_alias(struct remote *remote, const char *url)
128 {
129         add_url(remote, alias_url(url, &rewrites));
130         add_pushurl_alias(remote, url);
131 }
132
133 static struct remote *make_remote(const char *name, int len)
134 {
135         struct remote *ret;
136         int i;
137
138         for (i = 0; i < remotes_nr; i++) {
139                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
140                            !remotes[i]->name[len]) :
141                     !strcmp(name, remotes[i]->name))
142                         return remotes[i];
143         }
144
145         ret = xcalloc(1, sizeof(struct remote));
146         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
147         remotes[remotes_nr++] = ret;
148         if (len)
149                 ret->name = xstrndup(name, len);
150         else
151                 ret->name = xstrdup(name);
152         return ret;
153 }
154
155 static void add_merge(struct branch *branch, const char *name)
156 {
157         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
158                    branch->merge_alloc);
159         branch->merge_name[branch->merge_nr++] = name;
160 }
161
162 static struct branch *make_branch(const char *name, int len)
163 {
164         struct branch *ret;
165         int i;
166         char *refname;
167
168         for (i = 0; i < branches_nr; i++) {
169                 if (len ? (!strncmp(name, branches[i]->name, len) &&
170                            !branches[i]->name[len]) :
171                     !strcmp(name, branches[i]->name))
172                         return branches[i];
173         }
174
175         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
176         ret = xcalloc(1, sizeof(struct branch));
177         branches[branches_nr++] = ret;
178         if (len)
179                 ret->name = xstrndup(name, len);
180         else
181                 ret->name = xstrdup(name);
182         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
183         strcpy(refname, "refs/heads/");
184         strcpy(refname + strlen("refs/heads/"), ret->name);
185         ret->refname = refname;
186
187         return ret;
188 }
189
190 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
191 {
192         struct rewrite *ret;
193         int i;
194
195         for (i = 0; i < r->rewrite_nr; i++) {
196                 if (len
197                     ? (len == r->rewrite[i]->baselen &&
198                        !strncmp(base, r->rewrite[i]->base, len))
199                     : !strcmp(base, r->rewrite[i]->base))
200                         return r->rewrite[i];
201         }
202
203         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
204         ret = xcalloc(1, sizeof(struct rewrite));
205         r->rewrite[r->rewrite_nr++] = ret;
206         if (len) {
207                 ret->base = xstrndup(base, len);
208                 ret->baselen = len;
209         }
210         else {
211                 ret->base = xstrdup(base);
212                 ret->baselen = strlen(base);
213         }
214         return ret;
215 }
216
217 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
218 {
219         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
220         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
221         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
222         rewrite->instead_of_nr++;
223 }
224
225 static void read_remotes_file(struct remote *remote)
226 {
227         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
228
229         if (!f)
230                 return;
231         remote->origin = REMOTE_REMOTES;
232         while (fgets(buffer, BUF_SIZE, f)) {
233                 int value_list;
234                 char *s, *p;
235
236                 if (!prefixcmp(buffer, "URL:")) {
237                         value_list = 0;
238                         s = buffer + 4;
239                 } else if (!prefixcmp(buffer, "Push:")) {
240                         value_list = 1;
241                         s = buffer + 5;
242                 } else if (!prefixcmp(buffer, "Pull:")) {
243                         value_list = 2;
244                         s = buffer + 5;
245                 } else
246                         continue;
247
248                 while (isspace(*s))
249                         s++;
250                 if (!*s)
251                         continue;
252
253                 p = s + strlen(s);
254                 while (isspace(p[-1]))
255                         *--p = 0;
256
257                 switch (value_list) {
258                 case 0:
259                         add_url_alias(remote, xstrdup(s));
260                         break;
261                 case 1:
262                         add_push_refspec(remote, xstrdup(s));
263                         break;
264                 case 2:
265                         add_fetch_refspec(remote, xstrdup(s));
266                         break;
267                 }
268         }
269         fclose(f);
270 }
271
272 static void read_branches_file(struct remote *remote)
273 {
274         const char *slash = strchr(remote->name, '/');
275         char *frag;
276         struct strbuf branch = STRBUF_INIT;
277         int n = slash ? slash - remote->name : 1000;
278         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
279         char *s, *p;
280         int len;
281
282         if (!f)
283                 return;
284         s = fgets(buffer, BUF_SIZE, f);
285         fclose(f);
286         if (!s)
287                 return;
288         while (isspace(*s))
289                 s++;
290         if (!*s)
291                 return;
292         remote->origin = REMOTE_BRANCHES;
293         p = s + strlen(s);
294         while (isspace(p[-1]))
295                 *--p = 0;
296         len = p - s;
297         if (slash)
298                 len += strlen(slash);
299         p = xmalloc(len + 1);
300         strcpy(p, s);
301         if (slash)
302                 strcat(p, slash);
303
304         /*
305          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
306          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
307          * the partial URL obtained from the branches file plus
308          * "/netdev-2.6" and does not store it in any tracking ref.
309          * #branch specifier in the file is ignored.
310          *
311          * Otherwise, the branches file would have URL and optionally
312          * #branch specified.  The "master" (or specified) branch is
313          * fetched and stored in the local branch of the same name.
314          */
315         frag = strchr(p, '#');
316         if (frag) {
317                 *(frag++) = '\0';
318                 strbuf_addf(&branch, "refs/heads/%s", frag);
319         } else
320                 strbuf_addstr(&branch, "refs/heads/master");
321         if (!slash) {
322                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
323         } else {
324                 strbuf_reset(&branch);
325                 strbuf_addstr(&branch, "HEAD:");
326         }
327         add_url_alias(remote, p);
328         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
329         /*
330          * Cogito compatible push: push current HEAD to remote #branch
331          * (master if missing)
332          */
333         strbuf_init(&branch, 0);
334         strbuf_addstr(&branch, "HEAD");
335         if (frag)
336                 strbuf_addf(&branch, ":refs/heads/%s", frag);
337         else
338                 strbuf_addstr(&branch, ":refs/heads/master");
339         add_push_refspec(remote, strbuf_detach(&branch, NULL));
340         remote->fetch_tags = 1; /* always auto-follow */
341 }
342
343 static int handle_config(const char *key, const char *value, void *cb)
344 {
345         const char *name;
346         const char *subkey;
347         struct remote *remote;
348         struct branch *branch;
349         if (!prefixcmp(key, "branch.")) {
350                 name = key + 7;
351                 subkey = strrchr(name, '.');
352                 if (!subkey)
353                         return 0;
354                 branch = make_branch(name, subkey - name);
355                 if (!strcmp(subkey, ".remote")) {
356                         if (!value)
357                                 return config_error_nonbool(key);
358                         branch->remote_name = xstrdup(value);
359                         if (branch == current_branch) {
360                                 default_remote_name = branch->remote_name;
361                                 explicit_default_remote_name = 1;
362                         }
363                 } else if (!strcmp(subkey, ".merge")) {
364                         if (!value)
365                                 return config_error_nonbool(key);
366                         add_merge(branch, xstrdup(value));
367                 }
368                 return 0;
369         }
370         if (!prefixcmp(key, "url.")) {
371                 struct rewrite *rewrite;
372                 name = key + 4;
373                 subkey = strrchr(name, '.');
374                 if (!subkey)
375                         return 0;
376                 if (!strcmp(subkey, ".insteadof")) {
377                         rewrite = make_rewrite(&rewrites, name, subkey - name);
378                         if (!value)
379                                 return config_error_nonbool(key);
380                         add_instead_of(rewrite, xstrdup(value));
381                 } else if (!strcmp(subkey, ".pushinsteadof")) {
382                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
383                         if (!value)
384                                 return config_error_nonbool(key);
385                         add_instead_of(rewrite, xstrdup(value));
386                 }
387         }
388         if (prefixcmp(key,  "remote."))
389                 return 0;
390         name = key + 7;
391         if (*name == '/') {
392                 warning("Config remote shorthand cannot begin with '/': %s",
393                         name);
394                 return 0;
395         }
396         subkey = strrchr(name, '.');
397         if (!subkey)
398                 return 0;
399         remote = make_remote(name, subkey - name);
400         remote->origin = REMOTE_CONFIG;
401         if (!strcmp(subkey, ".mirror"))
402                 remote->mirror = git_config_bool(key, value);
403         else if (!strcmp(subkey, ".skipdefaultupdate"))
404                 remote->skip_default_update = git_config_bool(key, value);
405         else if (!strcmp(subkey, ".skipfetchall"))
406                 remote->skip_default_update = git_config_bool(key, value);
407         else if (!strcmp(subkey, ".url")) {
408                 const char *v;
409                 if (git_config_string(&v, key, value))
410                         return -1;
411                 add_url(remote, v);
412         } else if (!strcmp(subkey, ".pushurl")) {
413                 const char *v;
414                 if (git_config_string(&v, key, value))
415                         return -1;
416                 add_pushurl(remote, v);
417         } else if (!strcmp(subkey, ".push")) {
418                 const char *v;
419                 if (git_config_string(&v, key, value))
420                         return -1;
421                 add_push_refspec(remote, v);
422         } else if (!strcmp(subkey, ".fetch")) {
423                 const char *v;
424                 if (git_config_string(&v, key, value))
425                         return -1;
426                 add_fetch_refspec(remote, v);
427         } else if (!strcmp(subkey, ".receivepack")) {
428                 const char *v;
429                 if (git_config_string(&v, key, value))
430                         return -1;
431                 if (!remote->receivepack)
432                         remote->receivepack = v;
433                 else
434                         error("more than one receivepack given, using the first");
435         } else if (!strcmp(subkey, ".uploadpack")) {
436                 const char *v;
437                 if (git_config_string(&v, key, value))
438                         return -1;
439                 if (!remote->uploadpack)
440                         remote->uploadpack = v;
441                 else
442                         error("more than one uploadpack given, using the first");
443         } else if (!strcmp(subkey, ".tagopt")) {
444                 if (!strcmp(value, "--no-tags"))
445                         remote->fetch_tags = -1;
446                 else if (!strcmp(value, "--tags"))
447                         remote->fetch_tags = 2;
448         } else if (!strcmp(subkey, ".proxy")) {
449                 return git_config_string((const char **)&remote->http_proxy,
450                                          key, value);
451         } else if (!strcmp(subkey, ".vcs")) {
452                 return git_config_string(&remote->foreign_vcs, key, value);
453         }
454         return 0;
455 }
456
457 static void alias_all_urls(void)
458 {
459         int i, j;
460         for (i = 0; i < remotes_nr; i++) {
461                 int add_pushurl_aliases;
462                 if (!remotes[i])
463                         continue;
464                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
465                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
466                 }
467                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
468                 for (j = 0; j < remotes[i]->url_nr; j++) {
469                         if (add_pushurl_aliases)
470                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
471                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
472                 }
473         }
474 }
475
476 static void read_config(void)
477 {
478         unsigned char sha1[20];
479         const char *head_ref;
480         int flag;
481         if (default_remote_name) /* did this already */
482                 return;
483         default_remote_name = xstrdup("origin");
484         current_branch = NULL;
485         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
486         if (head_ref && (flag & REF_ISSYMREF) &&
487             !prefixcmp(head_ref, "refs/heads/")) {
488                 current_branch =
489                         make_branch(head_ref + strlen("refs/heads/"), 0);
490         }
491         git_config(handle_config, NULL);
492         alias_all_urls();
493 }
494
495 /*
496  * This function frees a refspec array.
497  * Warning: code paths should be checked to ensure that the src
498  *          and dst pointers are always freeable pointers as well
499  *          as the refspec pointer itself.
500  */
501 static void free_refspecs(struct refspec *refspec, int nr_refspec)
502 {
503         int i;
504
505         if (!refspec)
506                 return;
507
508         for (i = 0; i < nr_refspec; i++) {
509                 free(refspec[i].src);
510                 free(refspec[i].dst);
511         }
512         free(refspec);
513 }
514
515 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
516 {
517         int i;
518         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
519
520         for (i = 0; i < nr_refspec; i++) {
521                 size_t llen;
522                 int is_glob;
523                 const char *lhs, *rhs;
524                 int flags;
525
526                 is_glob = 0;
527
528                 lhs = refspec[i];
529                 if (*lhs == '+') {
530                         rs[i].force = 1;
531                         lhs++;
532                 }
533
534                 rhs = strrchr(lhs, ':');
535
536                 /*
537                  * Before going on, special case ":" (or "+:") as a refspec
538                  * for matching refs.
539                  */
540                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
541                         rs[i].matching = 1;
542                         continue;
543                 }
544
545                 if (rhs) {
546                         size_t rlen = strlen(++rhs);
547                         is_glob = (1 <= rlen && strchr(rhs, '*'));
548                         rs[i].dst = xstrndup(rhs, rlen);
549                 }
550
551                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
552                 if (1 <= llen && memchr(lhs, '*', llen)) {
553                         if ((rhs && !is_glob) || (!rhs && fetch))
554                                 goto invalid;
555                         is_glob = 1;
556                 } else if (rhs && is_glob) {
557                         goto invalid;
558                 }
559
560                 rs[i].pattern = is_glob;
561                 rs[i].src = xstrndup(lhs, llen);
562                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
563
564                 if (fetch) {
565                         /*
566                          * LHS
567                          * - empty is allowed; it means HEAD.
568                          * - otherwise it must be a valid looking ref.
569                          */
570                         if (!*rs[i].src)
571                                 ; /* empty is ok */
572                         else if (check_refname_format(rs[i].src, flags))
573                                 goto invalid;
574                         /*
575                          * RHS
576                          * - missing is ok, and is same as empty.
577                          * - empty is ok; it means not to store.
578                          * - otherwise it must be a valid looking ref.
579                          */
580                         if (!rs[i].dst)
581                                 ; /* ok */
582                         else if (!*rs[i].dst)
583                                 ; /* ok */
584                         else if (check_refname_format(rs[i].dst, flags))
585                                 goto invalid;
586                 } else {
587                         /*
588                          * LHS
589                          * - empty is allowed; it means delete.
590                          * - when wildcarded, it must be a valid looking ref.
591                          * - otherwise, it must be an extended SHA-1, but
592                          *   there is no existing way to validate this.
593                          */
594                         if (!*rs[i].src)
595                                 ; /* empty is ok */
596                         else if (is_glob) {
597                                 if (check_refname_format(rs[i].src, flags))
598                                         goto invalid;
599                         }
600                         else
601                                 ; /* anything goes, for now */
602                         /*
603                          * RHS
604                          * - missing is allowed, but LHS then must be a
605                          *   valid looking ref.
606                          * - empty is not allowed.
607                          * - otherwise it must be a valid looking ref.
608                          */
609                         if (!rs[i].dst) {
610                                 if (check_refname_format(rs[i].src, flags))
611                                         goto invalid;
612                         } else if (!*rs[i].dst) {
613                                 goto invalid;
614                         } else {
615                                 if (check_refname_format(rs[i].dst, flags))
616                                         goto invalid;
617                         }
618                 }
619         }
620         return rs;
621
622  invalid:
623         if (verify) {
624                 /*
625                  * nr_refspec must be greater than zero and i must be valid
626                  * since it is only possible to reach this point from within
627                  * the for loop above.
628                  */
629                 free_refspecs(rs, i+1);
630                 return NULL;
631         }
632         die("Invalid refspec '%s'", refspec[i]);
633 }
634
635 int valid_fetch_refspec(const char *fetch_refspec_str)
636 {
637         struct refspec *refspec;
638
639         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
640         free_refspecs(refspec, 1);
641         return !!refspec;
642 }
643
644 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
645 {
646         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
647 }
648
649 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
650 {
651         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
652 }
653
654 void free_refspec(int nr_refspec, struct refspec *refspec)
655 {
656         int i;
657         for (i = 0; i < nr_refspec; i++) {
658                 free(refspec[i].src);
659                 free(refspec[i].dst);
660         }
661         free(refspec);
662 }
663
664 static int valid_remote_nick(const char *name)
665 {
666         if (!name[0] || is_dot_or_dotdot(name))
667                 return 0;
668         return !strchr(name, '/'); /* no slash */
669 }
670
671 struct remote *remote_get(const char *name)
672 {
673         struct remote *ret;
674         int name_given = 0;
675
676         read_config();
677         if (name)
678                 name_given = 1;
679         else {
680                 name = default_remote_name;
681                 name_given = explicit_default_remote_name;
682         }
683
684         ret = make_remote(name, 0);
685         if (valid_remote_nick(name)) {
686                 if (!valid_remote(ret))
687                         read_remotes_file(ret);
688                 if (!valid_remote(ret))
689                         read_branches_file(ret);
690         }
691         if (name_given && !valid_remote(ret))
692                 add_url_alias(ret, name);
693         if (!valid_remote(ret))
694                 return NULL;
695         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
696         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
697         return ret;
698 }
699
700 int remote_is_configured(const char *name)
701 {
702         int i;
703         read_config();
704
705         for (i = 0; i < remotes_nr; i++)
706                 if (!strcmp(name, remotes[i]->name))
707                         return 1;
708         return 0;
709 }
710
711 int for_each_remote(each_remote_fn fn, void *priv)
712 {
713         int i, result = 0;
714         read_config();
715         for (i = 0; i < remotes_nr && !result; i++) {
716                 struct remote *r = remotes[i];
717                 if (!r)
718                         continue;
719                 if (!r->fetch)
720                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
721                                                        r->fetch_refspec);
722                 if (!r->push)
723                         r->push = parse_push_refspec(r->push_refspec_nr,
724                                                      r->push_refspec);
725                 result = fn(r, priv);
726         }
727         return result;
728 }
729
730 void ref_remove_duplicates(struct ref *ref_map)
731 {
732         struct string_list refs = STRING_LIST_INIT_NODUP;
733         struct string_list_item *item = NULL;
734         struct ref *prev = NULL, *next = NULL;
735         for (; ref_map; prev = ref_map, ref_map = next) {
736                 next = ref_map->next;
737                 if (!ref_map->peer_ref)
738                         continue;
739
740                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
741                 if (item) {
742                         if (strcmp(((struct ref *)item->util)->name,
743                                    ref_map->name))
744                                 die("%s tracks both %s and %s",
745                                     ref_map->peer_ref->name,
746                                     ((struct ref *)item->util)->name,
747                                     ref_map->name);
748                         prev->next = ref_map->next;
749                         free(ref_map->peer_ref);
750                         free(ref_map);
751                         ref_map = prev; /* skip this; we freed it */
752                         continue;
753                 }
754
755                 item = string_list_insert(&refs, ref_map->peer_ref->name);
756                 item->util = ref_map;
757         }
758         string_list_clear(&refs, 0);
759 }
760
761 int remote_has_url(struct remote *remote, const char *url)
762 {
763         int i;
764         for (i = 0; i < remote->url_nr; i++) {
765                 if (!strcmp(remote->url[i], url))
766                         return 1;
767         }
768         return 0;
769 }
770
771 static int match_name_with_pattern(const char *key, const char *name,
772                                    const char *value, char **result)
773 {
774         const char *kstar = strchr(key, '*');
775         size_t klen;
776         size_t ksuffixlen;
777         size_t namelen;
778         int ret;
779         if (!kstar)
780                 die("Key '%s' of pattern had no '*'", key);
781         klen = kstar - key;
782         ksuffixlen = strlen(kstar + 1);
783         namelen = strlen(name);
784         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
785                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
786         if (ret && value) {
787                 const char *vstar = strchr(value, '*');
788                 size_t vlen;
789                 size_t vsuffixlen;
790                 if (!vstar)
791                         die("Value '%s' of pattern has no '*'", value);
792                 vlen = vstar - value;
793                 vsuffixlen = strlen(vstar + 1);
794                 *result = xmalloc(vlen + vsuffixlen +
795                                   strlen(name) -
796                                   klen - ksuffixlen + 1);
797                 strncpy(*result, value, vlen);
798                 strncpy(*result + vlen,
799                         name + klen, namelen - klen - ksuffixlen);
800                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
801                        vstar + 1);
802         }
803         return ret;
804 }
805
806 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
807 {
808         int i;
809         int find_src = !query->src;
810
811         if (find_src && !query->dst)
812                 return error("query_refspecs: need either src or dst");
813
814         for (i = 0; i < ref_count; i++) {
815                 struct refspec *refspec = &refs[i];
816                 const char *key = find_src ? refspec->dst : refspec->src;
817                 const char *value = find_src ? refspec->src : refspec->dst;
818                 const char *needle = find_src ? query->dst : query->src;
819                 char **result = find_src ? &query->src : &query->dst;
820
821                 if (!refspec->dst)
822                         continue;
823                 if (refspec->pattern) {
824                         if (match_name_with_pattern(key, needle, value, result)) {
825                                 query->force = refspec->force;
826                                 return 0;
827                         }
828                 } else if (!strcmp(needle, key)) {
829                         *result = xstrdup(value);
830                         query->force = refspec->force;
831                         return 0;
832                 }
833         }
834         return -1;
835 }
836
837 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
838                      const char *name)
839 {
840         struct refspec query;
841
842         memset(&query, 0, sizeof(struct refspec));
843         query.src = (char *)name;
844
845         if (query_refspecs(refspecs, nr_refspec, &query))
846                 return NULL;
847
848         return query.dst;
849 }
850
851 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
852 {
853         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
854 }
855
856 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
857                 const char *name)
858 {
859         size_t len = strlen(name);
860         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
861         memcpy(ref->name, prefix, prefixlen);
862         memcpy(ref->name + prefixlen, name, len);
863         return ref;
864 }
865
866 struct ref *alloc_ref(const char *name)
867 {
868         return alloc_ref_with_prefix("", 0, name);
869 }
870
871 struct ref *copy_ref(const struct ref *ref)
872 {
873         struct ref *cpy;
874         size_t len;
875         if (!ref)
876                 return NULL;
877         len = strlen(ref->name);
878         cpy = xmalloc(sizeof(struct ref) + len + 1);
879         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
880         cpy->next = NULL;
881         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
882         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
883         cpy->peer_ref = copy_ref(ref->peer_ref);
884         return cpy;
885 }
886
887 struct ref *copy_ref_list(const struct ref *ref)
888 {
889         struct ref *ret = NULL;
890         struct ref **tail = &ret;
891         while (ref) {
892                 *tail = copy_ref(ref);
893                 ref = ref->next;
894                 tail = &((*tail)->next);
895         }
896         return ret;
897 }
898
899 static void free_ref(struct ref *ref)
900 {
901         if (!ref)
902                 return;
903         free_ref(ref->peer_ref);
904         free(ref->remote_status);
905         free(ref->symref);
906         free(ref);
907 }
908
909 void free_refs(struct ref *ref)
910 {
911         struct ref *next;
912         while (ref) {
913                 next = ref->next;
914                 free_ref(ref);
915                 ref = next;
916         }
917 }
918
919 static int count_refspec_match(const char *pattern,
920                                struct ref *refs,
921                                struct ref **matched_ref)
922 {
923         int patlen = strlen(pattern);
924         struct ref *matched_weak = NULL;
925         struct ref *matched = NULL;
926         int weak_match = 0;
927         int match = 0;
928
929         for (weak_match = match = 0; refs; refs = refs->next) {
930                 char *name = refs->name;
931                 int namelen = strlen(name);
932
933                 if (!refname_match(pattern, name, ref_rev_parse_rules))
934                         continue;
935
936                 /* A match is "weak" if it is with refs outside
937                  * heads or tags, and did not specify the pattern
938                  * in full (e.g. "refs/remotes/origin/master") or at
939                  * least from the toplevel (e.g. "remotes/origin/master");
940                  * otherwise "git push $URL master" would result in
941                  * ambiguity between remotes/origin/master and heads/master
942                  * at the remote site.
943                  */
944                 if (namelen != patlen &&
945                     patlen != namelen - 5 &&
946                     prefixcmp(name, "refs/heads/") &&
947                     prefixcmp(name, "refs/tags/")) {
948                         /* We want to catch the case where only weak
949                          * matches are found and there are multiple
950                          * matches, and where more than one strong
951                          * matches are found, as ambiguous.  One
952                          * strong match with zero or more weak matches
953                          * are acceptable as a unique match.
954                          */
955                         matched_weak = refs;
956                         weak_match++;
957                 }
958                 else {
959                         matched = refs;
960                         match++;
961                 }
962         }
963         if (!matched) {
964                 *matched_ref = matched_weak;
965                 return weak_match;
966         }
967         else {
968                 *matched_ref = matched;
969                 return match;
970         }
971 }
972
973 static void tail_link_ref(struct ref *ref, struct ref ***tail)
974 {
975         **tail = ref;
976         while (ref->next)
977                 ref = ref->next;
978         *tail = &ref->next;
979 }
980
981 static struct ref *try_explicit_object_name(const char *name)
982 {
983         unsigned char sha1[20];
984         struct ref *ref;
985
986         if (!*name) {
987                 ref = alloc_ref("(delete)");
988                 hashclr(ref->new_sha1);
989                 return ref;
990         }
991         if (get_sha1(name, sha1))
992                 return NULL;
993         ref = alloc_ref(name);
994         hashcpy(ref->new_sha1, sha1);
995         return ref;
996 }
997
998 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
999 {
1000         struct ref *ret = alloc_ref(name);
1001         tail_link_ref(ret, tail);
1002         return ret;
1003 }
1004
1005 static char *guess_ref(const char *name, struct ref *peer)
1006 {
1007         struct strbuf buf = STRBUF_INIT;
1008         unsigned char sha1[20];
1009
1010         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1011         if (!r)
1012                 return NULL;
1013
1014         if (!prefixcmp(r, "refs/heads/"))
1015                 strbuf_addstr(&buf, "refs/heads/");
1016         else if (!prefixcmp(r, "refs/tags/"))
1017                 strbuf_addstr(&buf, "refs/tags/");
1018         else
1019                 return NULL;
1020
1021         strbuf_addstr(&buf, name);
1022         return strbuf_detach(&buf, NULL);
1023 }
1024
1025 static int match_explicit(struct ref *src, struct ref *dst,
1026                           struct ref ***dst_tail,
1027                           struct refspec *rs)
1028 {
1029         struct ref *matched_src, *matched_dst;
1030         int copy_src;
1031
1032         const char *dst_value = rs->dst;
1033         char *dst_guess;
1034
1035         if (rs->pattern || rs->matching)
1036                 return 0;
1037
1038         matched_src = matched_dst = NULL;
1039         switch (count_refspec_match(rs->src, src, &matched_src)) {
1040         case 1:
1041                 copy_src = 1;
1042                 break;
1043         case 0:
1044                 /* The source could be in the get_sha1() format
1045                  * not a reference name.  :refs/other is a
1046                  * way to delete 'other' ref at the remote end.
1047                  */
1048                 matched_src = try_explicit_object_name(rs->src);
1049                 if (!matched_src)
1050                         return error("src refspec %s does not match any.", rs->src);
1051                 copy_src = 0;
1052                 break;
1053         default:
1054                 return error("src refspec %s matches more than one.", rs->src);
1055         }
1056
1057         if (!dst_value) {
1058                 unsigned char sha1[20];
1059                 int flag;
1060
1061                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1062                 if (!dst_value ||
1063                     ((flag & REF_ISSYMREF) &&
1064                      prefixcmp(dst_value, "refs/heads/")))
1065                         die("%s cannot be resolved to branch.",
1066                             matched_src->name);
1067         }
1068
1069         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1070         case 1:
1071                 break;
1072         case 0:
1073                 if (!memcmp(dst_value, "refs/", 5))
1074                         matched_dst = make_linked_ref(dst_value, dst_tail);
1075                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1076                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1077                 else
1078                         error("unable to push to unqualified destination: %s\n"
1079                               "The destination refspec neither matches an "
1080                               "existing ref on the remote nor\n"
1081                               "begins with refs/, and we are unable to "
1082                               "guess a prefix based on the source ref.",
1083                               dst_value);
1084                 break;
1085         default:
1086                 matched_dst = NULL;
1087                 error("dst refspec %s matches more than one.",
1088                       dst_value);
1089                 break;
1090         }
1091         if (!matched_dst)
1092                 return -1;
1093         if (matched_dst->peer_ref)
1094                 return error("dst ref %s receives from more than one src.",
1095                       matched_dst->name);
1096         else {
1097                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1098                 matched_dst->force = rs->force;
1099         }
1100         return 0;
1101 }
1102
1103 static int match_explicit_refs(struct ref *src, struct ref *dst,
1104                                struct ref ***dst_tail, struct refspec *rs,
1105                                int rs_nr)
1106 {
1107         int i, errs;
1108         for (i = errs = 0; i < rs_nr; i++)
1109                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1110         return errs;
1111 }
1112
1113 static const struct refspec *check_pattern_match(const struct refspec *rs,
1114                                                  int rs_nr,
1115                                                  const struct ref *src)
1116 {
1117         int i;
1118         int matching_refs = -1;
1119         for (i = 0; i < rs_nr; i++) {
1120                 if (rs[i].matching &&
1121                     (matching_refs == -1 || rs[i].force)) {
1122                         matching_refs = i;
1123                         continue;
1124                 }
1125
1126                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1127                                                              NULL, NULL))
1128                         return rs + i;
1129         }
1130         if (matching_refs != -1)
1131                 return rs + matching_refs;
1132         else
1133                 return NULL;
1134 }
1135
1136 static struct ref **tail_ref(struct ref **head)
1137 {
1138         struct ref **tail = head;
1139         while (*tail)
1140                 tail = &((*tail)->next);
1141         return tail;
1142 }
1143
1144 /*
1145  * Given the set of refs the local repository has, the set of refs the
1146  * remote repository has, and the refspec used for push, determine
1147  * what remote refs we will update and with what value by setting
1148  * peer_ref (which object is being pushed) and force (if the push is
1149  * forced) in elements of "dst". The function may add new elements to
1150  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1151  */
1152 int match_push_refs(struct ref *src, struct ref **dst,
1153                     int nr_refspec, const char **refspec, int flags)
1154 {
1155         struct refspec *rs;
1156         int send_all = flags & MATCH_REFS_ALL;
1157         int send_mirror = flags & MATCH_REFS_MIRROR;
1158         int errs;
1159         static const char *default_refspec[] = { ":", NULL };
1160         struct ref **dst_tail = tail_ref(dst);
1161
1162         if (!nr_refspec) {
1163                 nr_refspec = 1;
1164                 refspec = default_refspec;
1165         }
1166         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1167         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1168
1169         /* pick the remainder */
1170         for ( ; src; src = src->next) {
1171                 struct ref *dst_peer;
1172                 const struct refspec *pat = NULL;
1173                 char *dst_name;
1174                 if (src->peer_ref)
1175                         continue;
1176
1177                 pat = check_pattern_match(rs, nr_refspec, src);
1178                 if (!pat)
1179                         continue;
1180
1181                 if (pat->matching) {
1182                         /*
1183                          * "matching refs"; traditionally we pushed everything
1184                          * including refs outside refs/heads/ hierarchy, but
1185                          * that does not make much sense these days.
1186                          */
1187                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1188                                 continue;
1189                         dst_name = xstrdup(src->name);
1190
1191                 } else {
1192                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1193                         if (!match_name_with_pattern(pat->src, src->name,
1194                                                      dst_side, &dst_name))
1195                                 die("Didn't think it matches any more");
1196                 }
1197                 dst_peer = find_ref_by_name(*dst, dst_name);
1198                 if (dst_peer) {
1199                         if (dst_peer->peer_ref)
1200                                 /* We're already sending something to this ref. */
1201                                 goto free_name;
1202
1203                 } else {
1204                         if (pat->matching && !(send_all || send_mirror))
1205                                 /*
1206                                  * Remote doesn't have it, and we have no
1207                                  * explicit pattern, and we don't have
1208                                  * --all nor --mirror.
1209                                  */
1210                                 goto free_name;
1211
1212                         /* Create a new one and link it */
1213                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1214                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1215                 }
1216                 dst_peer->peer_ref = copy_ref(src);
1217                 dst_peer->force = pat->force;
1218         free_name:
1219                 free(dst_name);
1220         }
1221         if (errs)
1222                 return -1;
1223         return 0;
1224 }
1225
1226 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1227         int force_update)
1228 {
1229         struct ref *ref;
1230
1231         for (ref = remote_refs; ref; ref = ref->next) {
1232                 if (ref->peer_ref)
1233                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1234                 else if (!send_mirror)
1235                         continue;
1236
1237                 ref->deletion = is_null_sha1(ref->new_sha1);
1238                 if (!ref->deletion &&
1239                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1240                         ref->status = REF_STATUS_UPTODATE;
1241                         continue;
1242                 }
1243
1244                 /* This part determines what can overwrite what.
1245                  * The rules are:
1246                  *
1247                  * (0) you can always use --force or +A:B notation to
1248                  *     selectively force individual ref pairs.
1249                  *
1250                  * (1) if the old thing does not exist, it is OK.
1251                  *
1252                  * (2) if you do not have the old thing, you are not allowed
1253                  *     to overwrite it; you would not know what you are losing
1254                  *     otherwise.
1255                  *
1256                  * (3) if both new and old are commit-ish, and new is a
1257                  *     descendant of old, it is OK.
1258                  *
1259                  * (4) regardless of all of the above, removing :B is
1260                  *     always allowed.
1261                  */
1262
1263                 ref->nonfastforward =
1264                         !ref->deletion &&
1265                         !is_null_sha1(ref->old_sha1) &&
1266                         (!has_sha1_file(ref->old_sha1)
1267                           || !ref_newer(ref->new_sha1, ref->old_sha1));
1268
1269                 if (ref->nonfastforward && !ref->force && !force_update) {
1270                         ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
1271                         continue;
1272                 }
1273         }
1274 }
1275
1276 struct branch *branch_get(const char *name)
1277 {
1278         struct branch *ret;
1279
1280         read_config();
1281         if (!name || !*name || !strcmp(name, "HEAD"))
1282                 ret = current_branch;
1283         else
1284                 ret = make_branch(name, 0);
1285         if (ret && ret->remote_name) {
1286                 ret->remote = remote_get(ret->remote_name);
1287                 if (ret->merge_nr) {
1288                         int i;
1289                         ret->merge = xcalloc(sizeof(*ret->merge),
1290                                              ret->merge_nr);
1291                         for (i = 0; i < ret->merge_nr; i++) {
1292                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1293                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1294                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1295                                     && !strcmp(ret->remote_name, "."))
1296                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1297                         }
1298                 }
1299         }
1300         return ret;
1301 }
1302
1303 int branch_has_merge_config(struct branch *branch)
1304 {
1305         return branch && !!branch->merge;
1306 }
1307
1308 int branch_merge_matches(struct branch *branch,
1309                                  int i,
1310                                  const char *refname)
1311 {
1312         if (!branch || i < 0 || i >= branch->merge_nr)
1313                 return 0;
1314         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1315 }
1316
1317 static struct ref *get_expanded_map(const struct ref *remote_refs,
1318                                     const struct refspec *refspec)
1319 {
1320         const struct ref *ref;
1321         struct ref *ret = NULL;
1322         struct ref **tail = &ret;
1323
1324         char *expn_name;
1325
1326         for (ref = remote_refs; ref; ref = ref->next) {
1327                 if (strchr(ref->name, '^'))
1328                         continue; /* a dereference item */
1329                 if (match_name_with_pattern(refspec->src, ref->name,
1330                                             refspec->dst, &expn_name)) {
1331                         struct ref *cpy = copy_ref(ref);
1332
1333                         cpy->peer_ref = alloc_ref(expn_name);
1334                         free(expn_name);
1335                         if (refspec->force)
1336                                 cpy->peer_ref->force = 1;
1337                         *tail = cpy;
1338                         tail = &cpy->next;
1339                 }
1340         }
1341
1342         return ret;
1343 }
1344
1345 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1346 {
1347         const struct ref *ref;
1348         for (ref = refs; ref; ref = ref->next) {
1349                 if (refname_match(name, ref->name, ref_fetch_rules))
1350                         return ref;
1351         }
1352         return NULL;
1353 }
1354
1355 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1356 {
1357         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1358
1359         if (!ref)
1360                 return NULL;
1361
1362         return copy_ref(ref);
1363 }
1364
1365 static struct ref *get_local_ref(const char *name)
1366 {
1367         if (!name || name[0] == '\0')
1368                 return NULL;
1369
1370         if (!prefixcmp(name, "refs/"))
1371                 return alloc_ref(name);
1372
1373         if (!prefixcmp(name, "heads/") ||
1374             !prefixcmp(name, "tags/") ||
1375             !prefixcmp(name, "remotes/"))
1376                 return alloc_ref_with_prefix("refs/", 5, name);
1377
1378         return alloc_ref_with_prefix("refs/heads/", 11, name);
1379 }
1380
1381 int get_fetch_map(const struct ref *remote_refs,
1382                   const struct refspec *refspec,
1383                   struct ref ***tail,
1384                   int missing_ok)
1385 {
1386         struct ref *ref_map, **rmp;
1387
1388         if (refspec->pattern) {
1389                 ref_map = get_expanded_map(remote_refs, refspec);
1390         } else {
1391                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1392
1393                 ref_map = get_remote_ref(remote_refs, name);
1394                 if (!missing_ok && !ref_map)
1395                         die("Couldn't find remote ref %s", name);
1396                 if (ref_map) {
1397                         ref_map->peer_ref = get_local_ref(refspec->dst);
1398                         if (ref_map->peer_ref && refspec->force)
1399                                 ref_map->peer_ref->force = 1;
1400                 }
1401         }
1402
1403         for (rmp = &ref_map; *rmp; ) {
1404                 if ((*rmp)->peer_ref) {
1405                         if (check_refname_format((*rmp)->peer_ref->name + 5,
1406                                 REFNAME_ALLOW_ONELEVEL)) {
1407                                 struct ref *ignore = *rmp;
1408                                 error("* Ignoring funny ref '%s' locally",
1409                                       (*rmp)->peer_ref->name);
1410                                 *rmp = (*rmp)->next;
1411                                 free(ignore->peer_ref);
1412                                 free(ignore);
1413                                 continue;
1414                         }
1415                 }
1416                 rmp = &((*rmp)->next);
1417         }
1418
1419         if (ref_map)
1420                 tail_link_ref(ref_map, tail);
1421
1422         return 0;
1423 }
1424
1425 int resolve_remote_symref(struct ref *ref, struct ref *list)
1426 {
1427         if (!ref->symref)
1428                 return 0;
1429         for (; list; list = list->next)
1430                 if (!strcmp(ref->symref, list->name)) {
1431                         hashcpy(ref->old_sha1, list->old_sha1);
1432                         return 0;
1433                 }
1434         return 1;
1435 }
1436
1437 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1438 {
1439         while (list) {
1440                 struct commit_list *temp = list;
1441                 temp->item->object.flags &= ~mark;
1442                 list = temp->next;
1443                 free(temp);
1444         }
1445 }
1446
1447 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1448 {
1449         struct object *o;
1450         struct commit *old, *new;
1451         struct commit_list *list, *used;
1452         int found = 0;
1453
1454         /* Both new and old must be commit-ish and new is descendant of
1455          * old.  Otherwise we require --force.
1456          */
1457         o = deref_tag(parse_object(old_sha1), NULL, 0);
1458         if (!o || o->type != OBJ_COMMIT)
1459                 return 0;
1460         old = (struct commit *) o;
1461
1462         o = deref_tag(parse_object(new_sha1), NULL, 0);
1463         if (!o || o->type != OBJ_COMMIT)
1464                 return 0;
1465         new = (struct commit *) o;
1466
1467         if (parse_commit(new) < 0)
1468                 return 0;
1469
1470         used = list = NULL;
1471         commit_list_insert(new, &list);
1472         while (list) {
1473                 new = pop_most_recent_commit(&list, TMP_MARK);
1474                 commit_list_insert(new, &used);
1475                 if (new == old) {
1476                         found = 1;
1477                         break;
1478                 }
1479         }
1480         unmark_and_free(list, TMP_MARK);
1481         unmark_and_free(used, TMP_MARK);
1482         return found;
1483 }
1484
1485 /*
1486  * Return true if there is anything to report, otherwise false.
1487  */
1488 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1489 {
1490         unsigned char sha1[20];
1491         struct commit *ours, *theirs;
1492         char symmetric[84];
1493         struct rev_info revs;
1494         const char *rev_argv[10], *base;
1495         int rev_argc;
1496
1497         /*
1498          * Nothing to report unless we are marked to build on top of
1499          * somebody else.
1500          */
1501         if (!branch ||
1502             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1503                 return 0;
1504
1505         /*
1506          * If what we used to build on no longer exists, there is
1507          * nothing to report.
1508          */
1509         base = branch->merge[0]->dst;
1510         if (read_ref(base, sha1))
1511                 return 0;
1512         theirs = lookup_commit_reference(sha1);
1513         if (!theirs)
1514                 return 0;
1515
1516         if (read_ref(branch->refname, sha1))
1517                 return 0;
1518         ours = lookup_commit_reference(sha1);
1519         if (!ours)
1520                 return 0;
1521
1522         /* are we the same? */
1523         if (theirs == ours)
1524                 return 0;
1525
1526         /* Run "rev-list --left-right ours...theirs" internally... */
1527         rev_argc = 0;
1528         rev_argv[rev_argc++] = NULL;
1529         rev_argv[rev_argc++] = "--left-right";
1530         rev_argv[rev_argc++] = symmetric;
1531         rev_argv[rev_argc++] = "--";
1532         rev_argv[rev_argc] = NULL;
1533
1534         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1535         strcpy(symmetric + 40, "...");
1536         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1537
1538         init_revisions(&revs, NULL);
1539         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1540         prepare_revision_walk(&revs);
1541
1542         /* ... and count the commits on each side. */
1543         *num_ours = 0;
1544         *num_theirs = 0;
1545         while (1) {
1546                 struct commit *c = get_revision(&revs);
1547                 if (!c)
1548                         break;
1549                 if (c->object.flags & SYMMETRIC_LEFT)
1550                         (*num_ours)++;
1551                 else
1552                         (*num_theirs)++;
1553         }
1554
1555         /* clear object flags smudged by the above traversal */
1556         clear_commit_marks(ours, ALL_REV_FLAGS);
1557         clear_commit_marks(theirs, ALL_REV_FLAGS);
1558         return 1;
1559 }
1560
1561 /*
1562  * Return true when there is anything to report, otherwise false.
1563  */
1564 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1565 {
1566         int num_ours, num_theirs;
1567         const char *base;
1568
1569         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1570                 return 0;
1571
1572         base = branch->merge[0]->dst;
1573         base = shorten_unambiguous_ref(base, 0);
1574         if (!num_theirs)
1575                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1576                             "by %d commit%s.\n",
1577                             base, num_ours, (num_ours == 1) ? "" : "s");
1578         else if (!num_ours)
1579                 strbuf_addf(sb, "Your branch is behind '%s' "
1580                             "by %d commit%s, "
1581                             "and can be fast-forwarded.\n",
1582                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1583         else
1584                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1585                             "and have %d and %d different commit(s) each, "
1586                             "respectively.\n",
1587                             base, num_ours, num_theirs);
1588         return 1;
1589 }
1590
1591 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1592 {
1593         struct ref ***local_tail = cb_data;
1594         struct ref *ref;
1595         int len;
1596
1597         /* we already know it starts with refs/ to get here */
1598         if (check_refname_format(refname + 5, 0))
1599                 return 0;
1600
1601         len = strlen(refname) + 1;
1602         ref = xcalloc(1, sizeof(*ref) + len);
1603         hashcpy(ref->new_sha1, sha1);
1604         memcpy(ref->name, refname, len);
1605         **local_tail = ref;
1606         *local_tail = &ref->next;
1607         return 0;
1608 }
1609
1610 struct ref *get_local_heads(void)
1611 {
1612         struct ref *local_refs = NULL, **local_tail = &local_refs;
1613         for_each_ref(one_local_ref, &local_tail);
1614         return local_refs;
1615 }
1616
1617 struct ref *guess_remote_head(const struct ref *head,
1618                               const struct ref *refs,
1619                               int all)
1620 {
1621         const struct ref *r;
1622         struct ref *list = NULL;
1623         struct ref **tail = &list;
1624
1625         if (!head)
1626                 return NULL;
1627
1628         /*
1629          * Some transports support directly peeking at
1630          * where HEAD points; if that is the case, then
1631          * we don't have to guess.
1632          */
1633         if (head->symref)
1634                 return copy_ref(find_ref_by_name(refs, head->symref));
1635
1636         /* If refs/heads/master could be right, it is. */
1637         if (!all) {
1638                 r = find_ref_by_name(refs, "refs/heads/master");
1639                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1640                         return copy_ref(r);
1641         }
1642
1643         /* Look for another ref that points there */
1644         for (r = refs; r; r = r->next) {
1645                 if (r != head &&
1646                     !prefixcmp(r->name, "refs/heads/") &&
1647                     !hashcmp(r->old_sha1, head->old_sha1)) {
1648                         *tail = copy_ref(r);
1649                         tail = &((*tail)->next);
1650                         if (!all)
1651                                 break;
1652                 }
1653         }
1654
1655         return list;
1656 }
1657
1658 struct stale_heads_info {
1659         struct string_list *ref_names;
1660         struct ref **stale_refs_tail;
1661         struct refspec *refs;
1662         int ref_count;
1663 };
1664
1665 static int get_stale_heads_cb(const char *refname,
1666         const unsigned char *sha1, int flags, void *cb_data)
1667 {
1668         struct stale_heads_info *info = cb_data;
1669         struct refspec query;
1670         memset(&query, 0, sizeof(struct refspec));
1671         query.dst = (char *)refname;
1672
1673         if (query_refspecs(info->refs, info->ref_count, &query))
1674                 return 0; /* No matches */
1675
1676         /*
1677          * If we did find a suitable refspec and it's not a symref and
1678          * it's not in the list of refs that currently exist in that
1679          * remote we consider it to be stale.
1680          */
1681         if (!((flags & REF_ISSYMREF) ||
1682               string_list_has_string(info->ref_names, query.src))) {
1683                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1684                 hashcpy(ref->new_sha1, sha1);
1685         }
1686
1687         free(query.src);
1688         return 0;
1689 }
1690
1691 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1692 {
1693         struct ref *ref, *stale_refs = NULL;
1694         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1695         struct stale_heads_info info;
1696         info.ref_names = &ref_names;
1697         info.stale_refs_tail = &stale_refs;
1698         info.refs = refs;
1699         info.ref_count = ref_count;
1700         for (ref = fetch_map; ref; ref = ref->next)
1701                 string_list_append(&ref_names, ref->name);
1702         sort_string_list(&ref_names);
1703         for_each_ref(get_stale_heads_cb, &info);
1704         string_list_clear(&ref_names, 0);
1705         return stale_refs;
1706 }