Merge branch 'jk/unify-exit-code-by-receiving-signal'
[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 #include "mergesort.h"
11
12 enum map_direction { FROM_SRC, FROM_DST };
13
14 static struct refspec s_tag_refspec = {
15         0,
16         1,
17         0,
18         "refs/tags/*",
19         "refs/tags/*"
20 };
21
22 const struct refspec *tag_refspec = &s_tag_refspec;
23
24 struct counted_string {
25         size_t len;
26         const char *s;
27 };
28 struct rewrite {
29         const char *base;
30         size_t baselen;
31         struct counted_string *instead_of;
32         int instead_of_nr;
33         int instead_of_alloc;
34 };
35 struct rewrites {
36         struct rewrite **rewrite;
37         int rewrite_alloc;
38         int rewrite_nr;
39 };
40
41 static struct remote **remotes;
42 static int remotes_alloc;
43 static int remotes_nr;
44
45 static struct branch **branches;
46 static int branches_alloc;
47 static int branches_nr;
48
49 static struct branch *current_branch;
50 static const char *default_remote_name;
51 static int explicit_default_remote_name;
52
53 static struct rewrites rewrites;
54 static struct rewrites rewrites_push;
55
56 #define BUF_SIZE (2048)
57 static char buffer[BUF_SIZE];
58
59 static int valid_remote(const struct remote *remote)
60 {
61         return (!!remote->url) || (!!remote->foreign_vcs);
62 }
63
64 static const char *alias_url(const char *url, struct rewrites *r)
65 {
66         int i, j;
67         char *ret;
68         struct counted_string *longest;
69         int longest_i;
70
71         longest = NULL;
72         longest_i = -1;
73         for (i = 0; i < r->rewrite_nr; i++) {
74                 if (!r->rewrite[i])
75                         continue;
76                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
77                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
78                             (!longest ||
79                              longest->len < r->rewrite[i]->instead_of[j].len)) {
80                                 longest = &(r->rewrite[i]->instead_of[j]);
81                                 longest_i = i;
82                         }
83                 }
84         }
85         if (!longest)
86                 return url;
87
88         ret = xmalloc(r->rewrite[longest_i]->baselen +
89                      (strlen(url) - longest->len) + 1);
90         strcpy(ret, r->rewrite[longest_i]->base);
91         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
92         return ret;
93 }
94
95 static void add_push_refspec(struct remote *remote, const char *ref)
96 {
97         ALLOC_GROW(remote->push_refspec,
98                    remote->push_refspec_nr + 1,
99                    remote->push_refspec_alloc);
100         remote->push_refspec[remote->push_refspec_nr++] = ref;
101 }
102
103 static void add_fetch_refspec(struct remote *remote, const char *ref)
104 {
105         ALLOC_GROW(remote->fetch_refspec,
106                    remote->fetch_refspec_nr + 1,
107                    remote->fetch_refspec_alloc);
108         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
109 }
110
111 static void add_url(struct remote *remote, const char *url)
112 {
113         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
114         remote->url[remote->url_nr++] = url;
115 }
116
117 static void add_pushurl(struct remote *remote, const char *pushurl)
118 {
119         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
120         remote->pushurl[remote->pushurl_nr++] = pushurl;
121 }
122
123 static void add_pushurl_alias(struct remote *remote, const char *url)
124 {
125         const char *pushurl = alias_url(url, &rewrites_push);
126         if (pushurl != url)
127                 add_pushurl(remote, pushurl);
128 }
129
130 static void add_url_alias(struct remote *remote, const char *url)
131 {
132         add_url(remote, alias_url(url, &rewrites));
133         add_pushurl_alias(remote, url);
134 }
135
136 static struct remote *make_remote(const char *name, int len)
137 {
138         struct remote *ret;
139         int i;
140
141         for (i = 0; i < remotes_nr; i++) {
142                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
143                            !remotes[i]->name[len]) :
144                     !strcmp(name, remotes[i]->name))
145                         return remotes[i];
146         }
147
148         ret = xcalloc(1, sizeof(struct remote));
149         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
150         remotes[remotes_nr++] = ret;
151         if (len)
152                 ret->name = xstrndup(name, len);
153         else
154                 ret->name = xstrdup(name);
155         return ret;
156 }
157
158 static void add_merge(struct branch *branch, const char *name)
159 {
160         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
161                    branch->merge_alloc);
162         branch->merge_name[branch->merge_nr++] = name;
163 }
164
165 static struct branch *make_branch(const char *name, int len)
166 {
167         struct branch *ret;
168         int i;
169         char *refname;
170
171         for (i = 0; i < branches_nr; i++) {
172                 if (len ? (!strncmp(name, branches[i]->name, len) &&
173                            !branches[i]->name[len]) :
174                     !strcmp(name, branches[i]->name))
175                         return branches[i];
176         }
177
178         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
179         ret = xcalloc(1, sizeof(struct branch));
180         branches[branches_nr++] = ret;
181         if (len)
182                 ret->name = xstrndup(name, len);
183         else
184                 ret->name = xstrdup(name);
185         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
186         strcpy(refname, "refs/heads/");
187         strcpy(refname + strlen("refs/heads/"), ret->name);
188         ret->refname = refname;
189
190         return ret;
191 }
192
193 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
194 {
195         struct rewrite *ret;
196         int i;
197
198         for (i = 0; i < r->rewrite_nr; i++) {
199                 if (len
200                     ? (len == r->rewrite[i]->baselen &&
201                        !strncmp(base, r->rewrite[i]->base, len))
202                     : !strcmp(base, r->rewrite[i]->base))
203                         return r->rewrite[i];
204         }
205
206         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
207         ret = xcalloc(1, sizeof(struct rewrite));
208         r->rewrite[r->rewrite_nr++] = ret;
209         if (len) {
210                 ret->base = xstrndup(base, len);
211                 ret->baselen = len;
212         }
213         else {
214                 ret->base = xstrdup(base);
215                 ret->baselen = strlen(base);
216         }
217         return ret;
218 }
219
220 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
221 {
222         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
223         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
224         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
225         rewrite->instead_of_nr++;
226 }
227
228 static void read_remotes_file(struct remote *remote)
229 {
230         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
231
232         if (!f)
233                 return;
234         remote->origin = REMOTE_REMOTES;
235         while (fgets(buffer, BUF_SIZE, f)) {
236                 int value_list;
237                 char *s, *p;
238
239                 if (!prefixcmp(buffer, "URL:")) {
240                         value_list = 0;
241                         s = buffer + 4;
242                 } else if (!prefixcmp(buffer, "Push:")) {
243                         value_list = 1;
244                         s = buffer + 5;
245                 } else if (!prefixcmp(buffer, "Pull:")) {
246                         value_list = 2;
247                         s = buffer + 5;
248                 } else
249                         continue;
250
251                 while (isspace(*s))
252                         s++;
253                 if (!*s)
254                         continue;
255
256                 p = s + strlen(s);
257                 while (isspace(p[-1]))
258                         *--p = 0;
259
260                 switch (value_list) {
261                 case 0:
262                         add_url_alias(remote, xstrdup(s));
263                         break;
264                 case 1:
265                         add_push_refspec(remote, xstrdup(s));
266                         break;
267                 case 2:
268                         add_fetch_refspec(remote, xstrdup(s));
269                         break;
270                 }
271         }
272         fclose(f);
273 }
274
275 static void read_branches_file(struct remote *remote)
276 {
277         const char *slash = strchr(remote->name, '/');
278         char *frag;
279         struct strbuf branch = STRBUF_INIT;
280         int n = slash ? slash - remote->name : 1000;
281         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
282         char *s, *p;
283         int len;
284
285         if (!f)
286                 return;
287         s = fgets(buffer, BUF_SIZE, f);
288         fclose(f);
289         if (!s)
290                 return;
291         while (isspace(*s))
292                 s++;
293         if (!*s)
294                 return;
295         remote->origin = REMOTE_BRANCHES;
296         p = s + strlen(s);
297         while (isspace(p[-1]))
298                 *--p = 0;
299         len = p - s;
300         if (slash)
301                 len += strlen(slash);
302         p = xmalloc(len + 1);
303         strcpy(p, s);
304         if (slash)
305                 strcat(p, slash);
306
307         /*
308          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
309          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
310          * the partial URL obtained from the branches file plus
311          * "/netdev-2.6" and does not store it in any tracking ref.
312          * #branch specifier in the file is ignored.
313          *
314          * Otherwise, the branches file would have URL and optionally
315          * #branch specified.  The "master" (or specified) branch is
316          * fetched and stored in the local branch of the same name.
317          */
318         frag = strchr(p, '#');
319         if (frag) {
320                 *(frag++) = '\0';
321                 strbuf_addf(&branch, "refs/heads/%s", frag);
322         } else
323                 strbuf_addstr(&branch, "refs/heads/master");
324         if (!slash) {
325                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
326         } else {
327                 strbuf_reset(&branch);
328                 strbuf_addstr(&branch, "HEAD:");
329         }
330         add_url_alias(remote, p);
331         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
332         /*
333          * Cogito compatible push: push current HEAD to remote #branch
334          * (master if missing)
335          */
336         strbuf_init(&branch, 0);
337         strbuf_addstr(&branch, "HEAD");
338         if (frag)
339                 strbuf_addf(&branch, ":refs/heads/%s", frag);
340         else
341                 strbuf_addstr(&branch, ":refs/heads/master");
342         add_push_refspec(remote, strbuf_detach(&branch, NULL));
343         remote->fetch_tags = 1; /* always auto-follow */
344 }
345
346 static int handle_config(const char *key, const char *value, void *cb)
347 {
348         const char *name;
349         const char *subkey;
350         struct remote *remote;
351         struct branch *branch;
352         if (!prefixcmp(key, "branch.")) {
353                 name = key + 7;
354                 subkey = strrchr(name, '.');
355                 if (!subkey)
356                         return 0;
357                 branch = make_branch(name, subkey - name);
358                 if (!strcmp(subkey, ".remote")) {
359                         if (!value)
360                                 return config_error_nonbool(key);
361                         branch->remote_name = xstrdup(value);
362                         if (branch == current_branch) {
363                                 default_remote_name = branch->remote_name;
364                                 explicit_default_remote_name = 1;
365                         }
366                 } else if (!strcmp(subkey, ".merge")) {
367                         if (!value)
368                                 return config_error_nonbool(key);
369                         add_merge(branch, xstrdup(value));
370                 }
371                 return 0;
372         }
373         if (!prefixcmp(key, "url.")) {
374                 struct rewrite *rewrite;
375                 name = key + 4;
376                 subkey = strrchr(name, '.');
377                 if (!subkey)
378                         return 0;
379                 if (!strcmp(subkey, ".insteadof")) {
380                         rewrite = make_rewrite(&rewrites, name, subkey - name);
381                         if (!value)
382                                 return config_error_nonbool(key);
383                         add_instead_of(rewrite, xstrdup(value));
384                 } else if (!strcmp(subkey, ".pushinsteadof")) {
385                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
386                         if (!value)
387                                 return config_error_nonbool(key);
388                         add_instead_of(rewrite, xstrdup(value));
389                 }
390         }
391         if (prefixcmp(key,  "remote."))
392                 return 0;
393         name = key + 7;
394         if (*name == '/') {
395                 warning("Config remote shorthand cannot begin with '/': %s",
396                         name);
397                 return 0;
398         }
399         subkey = strrchr(name, '.');
400         if (!subkey)
401                 return 0;
402         remote = make_remote(name, subkey - name);
403         remote->origin = REMOTE_CONFIG;
404         if (!strcmp(subkey, ".mirror"))
405                 remote->mirror = git_config_bool(key, value);
406         else if (!strcmp(subkey, ".skipdefaultupdate"))
407                 remote->skip_default_update = git_config_bool(key, value);
408         else if (!strcmp(subkey, ".skipfetchall"))
409                 remote->skip_default_update = git_config_bool(key, value);
410         else if (!strcmp(subkey, ".url")) {
411                 const char *v;
412                 if (git_config_string(&v, key, value))
413                         return -1;
414                 add_url(remote, v);
415         } else if (!strcmp(subkey, ".pushurl")) {
416                 const char *v;
417                 if (git_config_string(&v, key, value))
418                         return -1;
419                 add_pushurl(remote, v);
420         } else if (!strcmp(subkey, ".push")) {
421                 const char *v;
422                 if (git_config_string(&v, key, value))
423                         return -1;
424                 add_push_refspec(remote, v);
425         } else if (!strcmp(subkey, ".fetch")) {
426                 const char *v;
427                 if (git_config_string(&v, key, value))
428                         return -1;
429                 add_fetch_refspec(remote, v);
430         } else if (!strcmp(subkey, ".receivepack")) {
431                 const char *v;
432                 if (git_config_string(&v, key, value))
433                         return -1;
434                 if (!remote->receivepack)
435                         remote->receivepack = v;
436                 else
437                         error("more than one receivepack given, using the first");
438         } else if (!strcmp(subkey, ".uploadpack")) {
439                 const char *v;
440                 if (git_config_string(&v, key, value))
441                         return -1;
442                 if (!remote->uploadpack)
443                         remote->uploadpack = v;
444                 else
445                         error("more than one uploadpack given, using the first");
446         } else if (!strcmp(subkey, ".tagopt")) {
447                 if (!strcmp(value, "--no-tags"))
448                         remote->fetch_tags = -1;
449                 else if (!strcmp(value, "--tags"))
450                         remote->fetch_tags = 2;
451         } else if (!strcmp(subkey, ".proxy")) {
452                 return git_config_string((const char **)&remote->http_proxy,
453                                          key, value);
454         } else if (!strcmp(subkey, ".vcs")) {
455                 return git_config_string(&remote->foreign_vcs, key, value);
456         }
457         return 0;
458 }
459
460 static void alias_all_urls(void)
461 {
462         int i, j;
463         for (i = 0; i < remotes_nr; i++) {
464                 int add_pushurl_aliases;
465                 if (!remotes[i])
466                         continue;
467                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
468                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
469                 }
470                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
471                 for (j = 0; j < remotes[i]->url_nr; j++) {
472                         if (add_pushurl_aliases)
473                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
474                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
475                 }
476         }
477 }
478
479 static void read_config(void)
480 {
481         unsigned char sha1[20];
482         const char *head_ref;
483         int flag;
484         if (default_remote_name) /* did this already */
485                 return;
486         default_remote_name = xstrdup("origin");
487         current_branch = NULL;
488         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
489         if (head_ref && (flag & REF_ISSYMREF) &&
490             !prefixcmp(head_ref, "refs/heads/")) {
491                 current_branch =
492                         make_branch(head_ref + strlen("refs/heads/"), 0);
493         }
494         git_config(handle_config, NULL);
495         alias_all_urls();
496 }
497
498 /*
499  * This function frees a refspec array.
500  * Warning: code paths should be checked to ensure that the src
501  *          and dst pointers are always freeable pointers as well
502  *          as the refspec pointer itself.
503  */
504 static void free_refspecs(struct refspec *refspec, int nr_refspec)
505 {
506         int i;
507
508         if (!refspec)
509                 return;
510
511         for (i = 0; i < nr_refspec; i++) {
512                 free(refspec[i].src);
513                 free(refspec[i].dst);
514         }
515         free(refspec);
516 }
517
518 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
519 {
520         int i;
521         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
522
523         for (i = 0; i < nr_refspec; i++) {
524                 size_t llen;
525                 int is_glob;
526                 const char *lhs, *rhs;
527                 int flags;
528
529                 is_glob = 0;
530
531                 lhs = refspec[i];
532                 if (*lhs == '+') {
533                         rs[i].force = 1;
534                         lhs++;
535                 }
536
537                 rhs = strrchr(lhs, ':');
538
539                 /*
540                  * Before going on, special case ":" (or "+:") as a refspec
541                  * for matching refs.
542                  */
543                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
544                         rs[i].matching = 1;
545                         continue;
546                 }
547
548                 if (rhs) {
549                         size_t rlen = strlen(++rhs);
550                         is_glob = (1 <= rlen && strchr(rhs, '*'));
551                         rs[i].dst = xstrndup(rhs, rlen);
552                 }
553
554                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
555                 if (1 <= llen && memchr(lhs, '*', llen)) {
556                         if ((rhs && !is_glob) || (!rhs && fetch))
557                                 goto invalid;
558                         is_glob = 1;
559                 } else if (rhs && is_glob) {
560                         goto invalid;
561                 }
562
563                 rs[i].pattern = is_glob;
564                 rs[i].src = xstrndup(lhs, llen);
565                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
566
567                 if (fetch) {
568                         /*
569                          * LHS
570                          * - empty is allowed; it means HEAD.
571                          * - otherwise it must be a valid looking ref.
572                          */
573                         if (!*rs[i].src)
574                                 ; /* empty is ok */
575                         else if (check_refname_format(rs[i].src, flags))
576                                 goto invalid;
577                         /*
578                          * RHS
579                          * - missing is ok, and is same as empty.
580                          * - empty is ok; it means not to store.
581                          * - otherwise it must be a valid looking ref.
582                          */
583                         if (!rs[i].dst)
584                                 ; /* ok */
585                         else if (!*rs[i].dst)
586                                 ; /* ok */
587                         else if (check_refname_format(rs[i].dst, flags))
588                                 goto invalid;
589                 } else {
590                         /*
591                          * LHS
592                          * - empty is allowed; it means delete.
593                          * - when wildcarded, it must be a valid looking ref.
594                          * - otherwise, it must be an extended SHA-1, but
595                          *   there is no existing way to validate this.
596                          */
597                         if (!*rs[i].src)
598                                 ; /* empty is ok */
599                         else if (is_glob) {
600                                 if (check_refname_format(rs[i].src, flags))
601                                         goto invalid;
602                         }
603                         else
604                                 ; /* anything goes, for now */
605                         /*
606                          * RHS
607                          * - missing is allowed, but LHS then must be a
608                          *   valid looking ref.
609                          * - empty is not allowed.
610                          * - otherwise it must be a valid looking ref.
611                          */
612                         if (!rs[i].dst) {
613                                 if (check_refname_format(rs[i].src, flags))
614                                         goto invalid;
615                         } else if (!*rs[i].dst) {
616                                 goto invalid;
617                         } else {
618                                 if (check_refname_format(rs[i].dst, flags))
619                                         goto invalid;
620                         }
621                 }
622         }
623         return rs;
624
625  invalid:
626         if (verify) {
627                 /*
628                  * nr_refspec must be greater than zero and i must be valid
629                  * since it is only possible to reach this point from within
630                  * the for loop above.
631                  */
632                 free_refspecs(rs, i+1);
633                 return NULL;
634         }
635         die("Invalid refspec '%s'", refspec[i]);
636 }
637
638 int valid_fetch_refspec(const char *fetch_refspec_str)
639 {
640         struct refspec *refspec;
641
642         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
643         free_refspecs(refspec, 1);
644         return !!refspec;
645 }
646
647 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
648 {
649         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
650 }
651
652 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
653 {
654         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
655 }
656
657 void free_refspec(int nr_refspec, struct refspec *refspec)
658 {
659         int i;
660         for (i = 0; i < nr_refspec; i++) {
661                 free(refspec[i].src);
662                 free(refspec[i].dst);
663         }
664         free(refspec);
665 }
666
667 static int valid_remote_nick(const char *name)
668 {
669         if (!name[0] || is_dot_or_dotdot(name))
670                 return 0;
671         return !strchr(name, '/'); /* no slash */
672 }
673
674 struct remote *remote_get(const char *name)
675 {
676         struct remote *ret;
677         int name_given = 0;
678
679         read_config();
680         if (name)
681                 name_given = 1;
682         else {
683                 name = default_remote_name;
684                 name_given = explicit_default_remote_name;
685         }
686
687         ret = make_remote(name, 0);
688         if (valid_remote_nick(name)) {
689                 if (!valid_remote(ret))
690                         read_remotes_file(ret);
691                 if (!valid_remote(ret))
692                         read_branches_file(ret);
693         }
694         if (name_given && !valid_remote(ret))
695                 add_url_alias(ret, name);
696         if (!valid_remote(ret))
697                 return NULL;
698         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
699         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
700         return ret;
701 }
702
703 int remote_is_configured(const char *name)
704 {
705         int i;
706         read_config();
707
708         for (i = 0; i < remotes_nr; i++)
709                 if (!strcmp(name, remotes[i]->name))
710                         return 1;
711         return 0;
712 }
713
714 int for_each_remote(each_remote_fn fn, void *priv)
715 {
716         int i, result = 0;
717         read_config();
718         for (i = 0; i < remotes_nr && !result; i++) {
719                 struct remote *r = remotes[i];
720                 if (!r)
721                         continue;
722                 if (!r->fetch)
723                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
724                                                        r->fetch_refspec);
725                 if (!r->push)
726                         r->push = parse_push_refspec(r->push_refspec_nr,
727                                                      r->push_refspec);
728                 result = fn(r, priv);
729         }
730         return result;
731 }
732
733 void ref_remove_duplicates(struct ref *ref_map)
734 {
735         struct string_list refs = STRING_LIST_INIT_NODUP;
736         struct string_list_item *item = NULL;
737         struct ref *prev = NULL, *next = NULL;
738         for (; ref_map; prev = ref_map, ref_map = next) {
739                 next = ref_map->next;
740                 if (!ref_map->peer_ref)
741                         continue;
742
743                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
744                 if (item) {
745                         if (strcmp(((struct ref *)item->util)->name,
746                                    ref_map->name))
747                                 die("%s tracks both %s and %s",
748                                     ref_map->peer_ref->name,
749                                     ((struct ref *)item->util)->name,
750                                     ref_map->name);
751                         prev->next = ref_map->next;
752                         free(ref_map->peer_ref);
753                         free(ref_map);
754                         ref_map = prev; /* skip this; we freed it */
755                         continue;
756                 }
757
758                 item = string_list_insert(&refs, ref_map->peer_ref->name);
759                 item->util = ref_map;
760         }
761         string_list_clear(&refs, 0);
762 }
763
764 int remote_has_url(struct remote *remote, const char *url)
765 {
766         int i;
767         for (i = 0; i < remote->url_nr; i++) {
768                 if (!strcmp(remote->url[i], url))
769                         return 1;
770         }
771         return 0;
772 }
773
774 static int match_name_with_pattern(const char *key, const char *name,
775                                    const char *value, char **result)
776 {
777         const char *kstar = strchr(key, '*');
778         size_t klen;
779         size_t ksuffixlen;
780         size_t namelen;
781         int ret;
782         if (!kstar)
783                 die("Key '%s' of pattern had no '*'", key);
784         klen = kstar - key;
785         ksuffixlen = strlen(kstar + 1);
786         namelen = strlen(name);
787         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
788                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
789         if (ret && value) {
790                 const char *vstar = strchr(value, '*');
791                 size_t vlen;
792                 size_t vsuffixlen;
793                 if (!vstar)
794                         die("Value '%s' of pattern has no '*'", value);
795                 vlen = vstar - value;
796                 vsuffixlen = strlen(vstar + 1);
797                 *result = xmalloc(vlen + vsuffixlen +
798                                   strlen(name) -
799                                   klen - ksuffixlen + 1);
800                 strncpy(*result, value, vlen);
801                 strncpy(*result + vlen,
802                         name + klen, namelen - klen - ksuffixlen);
803                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
804                        vstar + 1);
805         }
806         return ret;
807 }
808
809 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
810 {
811         int i;
812         int find_src = !query->src;
813
814         if (find_src && !query->dst)
815                 return error("query_refspecs: need either src or dst");
816
817         for (i = 0; i < ref_count; i++) {
818                 struct refspec *refspec = &refs[i];
819                 const char *key = find_src ? refspec->dst : refspec->src;
820                 const char *value = find_src ? refspec->src : refspec->dst;
821                 const char *needle = find_src ? query->dst : query->src;
822                 char **result = find_src ? &query->src : &query->dst;
823
824                 if (!refspec->dst)
825                         continue;
826                 if (refspec->pattern) {
827                         if (match_name_with_pattern(key, needle, value, result)) {
828                                 query->force = refspec->force;
829                                 return 0;
830                         }
831                 } else if (!strcmp(needle, key)) {
832                         *result = xstrdup(value);
833                         query->force = refspec->force;
834                         return 0;
835                 }
836         }
837         return -1;
838 }
839
840 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
841                      const char *name)
842 {
843         struct refspec query;
844
845         memset(&query, 0, sizeof(struct refspec));
846         query.src = (char *)name;
847
848         if (query_refspecs(refspecs, nr_refspec, &query))
849                 return NULL;
850
851         return query.dst;
852 }
853
854 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
855 {
856         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
857 }
858
859 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
860                 const char *name)
861 {
862         size_t len = strlen(name);
863         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
864         memcpy(ref->name, prefix, prefixlen);
865         memcpy(ref->name + prefixlen, name, len);
866         return ref;
867 }
868
869 struct ref *alloc_ref(const char *name)
870 {
871         return alloc_ref_with_prefix("", 0, name);
872 }
873
874 struct ref *copy_ref(const struct ref *ref)
875 {
876         struct ref *cpy;
877         size_t len;
878         if (!ref)
879                 return NULL;
880         len = strlen(ref->name);
881         cpy = xmalloc(sizeof(struct ref) + len + 1);
882         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
883         cpy->next = NULL;
884         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
885         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
886         cpy->peer_ref = copy_ref(ref->peer_ref);
887         return cpy;
888 }
889
890 struct ref *copy_ref_list(const struct ref *ref)
891 {
892         struct ref *ret = NULL;
893         struct ref **tail = &ret;
894         while (ref) {
895                 *tail = copy_ref(ref);
896                 ref = ref->next;
897                 tail = &((*tail)->next);
898         }
899         return ret;
900 }
901
902 static void free_ref(struct ref *ref)
903 {
904         if (!ref)
905                 return;
906         free_ref(ref->peer_ref);
907         free(ref->remote_status);
908         free(ref->symref);
909         free(ref);
910 }
911
912 void free_refs(struct ref *ref)
913 {
914         struct ref *next;
915         while (ref) {
916                 next = ref->next;
917                 free_ref(ref);
918                 ref = next;
919         }
920 }
921
922 int ref_compare_name(const void *va, const void *vb)
923 {
924         const struct ref *a = va, *b = vb;
925         return strcmp(a->name, b->name);
926 }
927
928 static void *ref_list_get_next(const void *a)
929 {
930         return ((const struct ref *)a)->next;
931 }
932
933 static void ref_list_set_next(void *a, void *next)
934 {
935         ((struct ref *)a)->next = next;
936 }
937
938 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
939 {
940         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
941 }
942
943 static int count_refspec_match(const char *pattern,
944                                struct ref *refs,
945                                struct ref **matched_ref)
946 {
947         int patlen = strlen(pattern);
948         struct ref *matched_weak = NULL;
949         struct ref *matched = NULL;
950         int weak_match = 0;
951         int match = 0;
952
953         for (weak_match = match = 0; refs; refs = refs->next) {
954                 char *name = refs->name;
955                 int namelen = strlen(name);
956
957                 if (!refname_match(pattern, name, ref_rev_parse_rules))
958                         continue;
959
960                 /* A match is "weak" if it is with refs outside
961                  * heads or tags, and did not specify the pattern
962                  * in full (e.g. "refs/remotes/origin/master") or at
963                  * least from the toplevel (e.g. "remotes/origin/master");
964                  * otherwise "git push $URL master" would result in
965                  * ambiguity between remotes/origin/master and heads/master
966                  * at the remote site.
967                  */
968                 if (namelen != patlen &&
969                     patlen != namelen - 5 &&
970                     prefixcmp(name, "refs/heads/") &&
971                     prefixcmp(name, "refs/tags/")) {
972                         /* We want to catch the case where only weak
973                          * matches are found and there are multiple
974                          * matches, and where more than one strong
975                          * matches are found, as ambiguous.  One
976                          * strong match with zero or more weak matches
977                          * are acceptable as a unique match.
978                          */
979                         matched_weak = refs;
980                         weak_match++;
981                 }
982                 else {
983                         matched = refs;
984                         match++;
985                 }
986         }
987         if (!matched) {
988                 *matched_ref = matched_weak;
989                 return weak_match;
990         }
991         else {
992                 *matched_ref = matched;
993                 return match;
994         }
995 }
996
997 static void tail_link_ref(struct ref *ref, struct ref ***tail)
998 {
999         **tail = ref;
1000         while (ref->next)
1001                 ref = ref->next;
1002         *tail = &ref->next;
1003 }
1004
1005 static struct ref *alloc_delete_ref(void)
1006 {
1007         struct ref *ref = alloc_ref("(delete)");
1008         hashclr(ref->new_sha1);
1009         return ref;
1010 }
1011
1012 static struct ref *try_explicit_object_name(const char *name)
1013 {
1014         unsigned char sha1[20];
1015         struct ref *ref;
1016
1017         if (!*name)
1018                 return alloc_delete_ref();
1019         if (get_sha1(name, sha1))
1020                 return NULL;
1021         ref = alloc_ref(name);
1022         hashcpy(ref->new_sha1, sha1);
1023         return ref;
1024 }
1025
1026 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1027 {
1028         struct ref *ret = alloc_ref(name);
1029         tail_link_ref(ret, tail);
1030         return ret;
1031 }
1032
1033 static char *guess_ref(const char *name, struct ref *peer)
1034 {
1035         struct strbuf buf = STRBUF_INIT;
1036         unsigned char sha1[20];
1037
1038         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1039         if (!r)
1040                 return NULL;
1041
1042         if (!prefixcmp(r, "refs/heads/"))
1043                 strbuf_addstr(&buf, "refs/heads/");
1044         else if (!prefixcmp(r, "refs/tags/"))
1045                 strbuf_addstr(&buf, "refs/tags/");
1046         else
1047                 return NULL;
1048
1049         strbuf_addstr(&buf, name);
1050         return strbuf_detach(&buf, NULL);
1051 }
1052
1053 static int match_explicit(struct ref *src, struct ref *dst,
1054                           struct ref ***dst_tail,
1055                           struct refspec *rs)
1056 {
1057         struct ref *matched_src, *matched_dst;
1058         int copy_src;
1059
1060         const char *dst_value = rs->dst;
1061         char *dst_guess;
1062
1063         if (rs->pattern || rs->matching)
1064                 return 0;
1065
1066         matched_src = matched_dst = NULL;
1067         switch (count_refspec_match(rs->src, src, &matched_src)) {
1068         case 1:
1069                 copy_src = 1;
1070                 break;
1071         case 0:
1072                 /* The source could be in the get_sha1() format
1073                  * not a reference name.  :refs/other is a
1074                  * way to delete 'other' ref at the remote end.
1075                  */
1076                 matched_src = try_explicit_object_name(rs->src);
1077                 if (!matched_src)
1078                         return error("src refspec %s does not match any.", rs->src);
1079                 copy_src = 0;
1080                 break;
1081         default:
1082                 return error("src refspec %s matches more than one.", rs->src);
1083         }
1084
1085         if (!dst_value) {
1086                 unsigned char sha1[20];
1087                 int flag;
1088
1089                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1090                 if (!dst_value ||
1091                     ((flag & REF_ISSYMREF) &&
1092                      prefixcmp(dst_value, "refs/heads/")))
1093                         die("%s cannot be resolved to branch.",
1094                             matched_src->name);
1095         }
1096
1097         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1098         case 1:
1099                 break;
1100         case 0:
1101                 if (!memcmp(dst_value, "refs/", 5))
1102                         matched_dst = make_linked_ref(dst_value, dst_tail);
1103                 else if (is_null_sha1(matched_src->new_sha1))
1104                         error("unable to delete '%s': remote ref does not exist",
1105                               dst_value);
1106                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1107                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1108                 else
1109                         error("unable to push to unqualified destination: %s\n"
1110                               "The destination refspec neither matches an "
1111                               "existing ref on the remote nor\n"
1112                               "begins with refs/, and we are unable to "
1113                               "guess a prefix based on the source ref.",
1114                               dst_value);
1115                 break;
1116         default:
1117                 matched_dst = NULL;
1118                 error("dst refspec %s matches more than one.",
1119                       dst_value);
1120                 break;
1121         }
1122         if (!matched_dst)
1123                 return -1;
1124         if (matched_dst->peer_ref)
1125                 return error("dst ref %s receives from more than one src.",
1126                       matched_dst->name);
1127         else {
1128                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1129                 matched_dst->force = rs->force;
1130         }
1131         return 0;
1132 }
1133
1134 static int match_explicit_refs(struct ref *src, struct ref *dst,
1135                                struct ref ***dst_tail, struct refspec *rs,
1136                                int rs_nr)
1137 {
1138         int i, errs;
1139         for (i = errs = 0; i < rs_nr; i++)
1140                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1141         return errs;
1142 }
1143
1144 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1145                 int send_mirror, int direction, const struct refspec **ret_pat)
1146 {
1147         const struct refspec *pat;
1148         char *name;
1149         int i;
1150         int matching_refs = -1;
1151         for (i = 0; i < rs_nr; i++) {
1152                 if (rs[i].matching &&
1153                     (matching_refs == -1 || rs[i].force)) {
1154                         matching_refs = i;
1155                         continue;
1156                 }
1157
1158                 if (rs[i].pattern) {
1159                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1160                         int match;
1161                         if (direction == FROM_SRC)
1162                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1163                         else
1164                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1165                         if (match) {
1166                                 matching_refs = i;
1167                                 break;
1168                         }
1169                 }
1170         }
1171         if (matching_refs == -1)
1172                 return NULL;
1173
1174         pat = rs + matching_refs;
1175         if (pat->matching) {
1176                 /*
1177                  * "matching refs"; traditionally we pushed everything
1178                  * including refs outside refs/heads/ hierarchy, but
1179                  * that does not make much sense these days.
1180                  */
1181                 if (!send_mirror && prefixcmp(ref->name, "refs/heads/"))
1182                         return NULL;
1183                 name = xstrdup(ref->name);
1184         }
1185         if (ret_pat)
1186                 *ret_pat = pat;
1187         return name;
1188 }
1189
1190 static struct ref **tail_ref(struct ref **head)
1191 {
1192         struct ref **tail = head;
1193         while (*tail)
1194                 tail = &((*tail)->next);
1195         return tail;
1196 }
1197
1198 /*
1199  * Given the set of refs the local repository has, the set of refs the
1200  * remote repository has, and the refspec used for push, determine
1201  * what remote refs we will update and with what value by setting
1202  * peer_ref (which object is being pushed) and force (if the push is
1203  * forced) in elements of "dst". The function may add new elements to
1204  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1205  */
1206 int match_push_refs(struct ref *src, struct ref **dst,
1207                     int nr_refspec, const char **refspec, int flags)
1208 {
1209         struct refspec *rs;
1210         int send_all = flags & MATCH_REFS_ALL;
1211         int send_mirror = flags & MATCH_REFS_MIRROR;
1212         int send_prune = flags & MATCH_REFS_PRUNE;
1213         int errs;
1214         static const char *default_refspec[] = { ":", NULL };
1215         struct ref *ref, **dst_tail = tail_ref(dst);
1216
1217         if (!nr_refspec) {
1218                 nr_refspec = 1;
1219                 refspec = default_refspec;
1220         }
1221         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1222         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1223
1224         /* pick the remainder */
1225         for (ref = src; ref; ref = ref->next) {
1226                 struct ref *dst_peer;
1227                 const struct refspec *pat = NULL;
1228                 char *dst_name;
1229
1230                 if (ref->peer_ref)
1231                         continue;
1232
1233                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1234                 if (!dst_name)
1235                         continue;
1236
1237                 dst_peer = find_ref_by_name(*dst, dst_name);
1238                 if (dst_peer) {
1239                         if (dst_peer->peer_ref)
1240                                 /* We're already sending something to this ref. */
1241                                 goto free_name;
1242                 } else {
1243                         if (pat->matching && !(send_all || send_mirror))
1244                                 /*
1245                                  * Remote doesn't have it, and we have no
1246                                  * explicit pattern, and we don't have
1247                                  * --all nor --mirror.
1248                                  */
1249                                 goto free_name;
1250
1251                         /* Create a new one and link it */
1252                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1253                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1254                 }
1255                 dst_peer->peer_ref = copy_ref(ref);
1256                 dst_peer->force = pat->force;
1257         free_name:
1258                 free(dst_name);
1259         }
1260         if (send_prune) {
1261                 /* check for missing refs on the remote */
1262                 for (ref = *dst; ref; ref = ref->next) {
1263                         char *src_name;
1264
1265                         if (ref->peer_ref)
1266                                 /* We're already sending something to this ref. */
1267                                 continue;
1268
1269                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1270                         if (src_name) {
1271                                 if (!find_ref_by_name(src, src_name))
1272                                         ref->peer_ref = alloc_delete_ref();
1273                                 free(src_name);
1274                         }
1275                 }
1276         }
1277         if (errs)
1278                 return -1;
1279         return 0;
1280 }
1281
1282 static inline int is_forwardable(struct ref* ref)
1283 {
1284         struct object *o;
1285
1286         if (!prefixcmp(ref->name, "refs/tags/"))
1287                 return 0;
1288
1289         /* old object must be a commit */
1290         o = parse_object(ref->old_sha1);
1291         if (!o || o->type != OBJ_COMMIT)
1292                 return 0;
1293
1294         /* new object must be commit-ish */
1295         o = deref_tag(parse_object(ref->new_sha1), NULL, 0);
1296         if (!o || o->type != OBJ_COMMIT)
1297                 return 0;
1298
1299         return 1;
1300 }
1301
1302 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1303         int force_update)
1304 {
1305         struct ref *ref;
1306
1307         for (ref = remote_refs; ref; ref = ref->next) {
1308                 int force_ref_update = ref->force || force_update;
1309
1310                 if (ref->peer_ref)
1311                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1312                 else if (!send_mirror)
1313                         continue;
1314
1315                 ref->deletion = is_null_sha1(ref->new_sha1);
1316                 if (!ref->deletion &&
1317                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1318                         ref->status = REF_STATUS_UPTODATE;
1319                         continue;
1320                 }
1321
1322                 /*
1323                  * The below logic determines whether an individual
1324                  * refspec A:B can be pushed.  The push will succeed
1325                  * if any of the following are true:
1326                  *
1327                  * (1) the remote reference B does not exist
1328                  *
1329                  * (2) the remote reference B is being removed (i.e.,
1330                  *     pushing :B where no source is specified)
1331                  *
1332                  * (3) the update meets all fast-forwarding criteria:
1333                  *
1334                  *     (a) the destination is not under refs/tags/
1335                  *     (b) the old is a commit
1336                  *     (c) the new is a descendant of the old
1337                  *
1338                  *     NOTE: We must actually have the old object in
1339                  *     order to overwrite it in the remote reference,
1340                  *     and the new object must be commit-ish.  These are
1341                  *     implied by (b) and (c) respectively.
1342                  *
1343                  * (4) it is forced using the +A:B notation, or by
1344                  *     passing the --force argument
1345                  */
1346
1347                 ref->not_forwardable = !is_forwardable(ref);
1348
1349                 ref->update =
1350                         !ref->deletion &&
1351                         !is_null_sha1(ref->old_sha1);
1352
1353                 if (ref->update) {
1354                         ref->nonfastforward =
1355                                 !has_sha1_file(ref->old_sha1)
1356                                   || !ref_newer(ref->new_sha1, ref->old_sha1);
1357
1358                         if (ref->not_forwardable) {
1359                                 ref->requires_force = 1;
1360                                 if (!force_ref_update) {
1361                                         ref->status = REF_STATUS_REJECT_ALREADY_EXISTS;
1362                                         continue;
1363                                 }
1364                         } else if (ref->nonfastforward) {
1365                                 ref->requires_force = 1;
1366                                 if (!force_ref_update) {
1367                                         ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
1368                                         continue;
1369                                 }
1370                         }
1371                 }
1372         }
1373 }
1374
1375 struct branch *branch_get(const char *name)
1376 {
1377         struct branch *ret;
1378
1379         read_config();
1380         if (!name || !*name || !strcmp(name, "HEAD"))
1381                 ret = current_branch;
1382         else
1383                 ret = make_branch(name, 0);
1384         if (ret && ret->remote_name) {
1385                 ret->remote = remote_get(ret->remote_name);
1386                 if (ret->merge_nr) {
1387                         int i;
1388                         ret->merge = xcalloc(sizeof(*ret->merge),
1389                                              ret->merge_nr);
1390                         for (i = 0; i < ret->merge_nr; i++) {
1391                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1392                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1393                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1394                                     && !strcmp(ret->remote_name, "."))
1395                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1396                         }
1397                 }
1398         }
1399         return ret;
1400 }
1401
1402 int branch_has_merge_config(struct branch *branch)
1403 {
1404         return branch && !!branch->merge;
1405 }
1406
1407 int branch_merge_matches(struct branch *branch,
1408                                  int i,
1409                                  const char *refname)
1410 {
1411         if (!branch || i < 0 || i >= branch->merge_nr)
1412                 return 0;
1413         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1414 }
1415
1416 static int ignore_symref_update(const char *refname)
1417 {
1418         unsigned char sha1[20];
1419         int flag;
1420
1421         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1422                 return 0; /* non-existing refs are OK */
1423         return (flag & REF_ISSYMREF);
1424 }
1425
1426 static struct ref *get_expanded_map(const struct ref *remote_refs,
1427                                     const struct refspec *refspec)
1428 {
1429         const struct ref *ref;
1430         struct ref *ret = NULL;
1431         struct ref **tail = &ret;
1432
1433         char *expn_name;
1434
1435         for (ref = remote_refs; ref; ref = ref->next) {
1436                 if (strchr(ref->name, '^'))
1437                         continue; /* a dereference item */
1438                 if (match_name_with_pattern(refspec->src, ref->name,
1439                                             refspec->dst, &expn_name) &&
1440                     !ignore_symref_update(expn_name)) {
1441                         struct ref *cpy = copy_ref(ref);
1442
1443                         cpy->peer_ref = alloc_ref(expn_name);
1444                         free(expn_name);
1445                         if (refspec->force)
1446                                 cpy->peer_ref->force = 1;
1447                         *tail = cpy;
1448                         tail = &cpy->next;
1449                 }
1450         }
1451
1452         return ret;
1453 }
1454
1455 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1456 {
1457         const struct ref *ref;
1458         for (ref = refs; ref; ref = ref->next) {
1459                 if (refname_match(name, ref->name, ref_fetch_rules))
1460                         return ref;
1461         }
1462         return NULL;
1463 }
1464
1465 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1466 {
1467         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1468
1469         if (!ref)
1470                 return NULL;
1471
1472         return copy_ref(ref);
1473 }
1474
1475 static struct ref *get_local_ref(const char *name)
1476 {
1477         if (!name || name[0] == '\0')
1478                 return NULL;
1479
1480         if (!prefixcmp(name, "refs/"))
1481                 return alloc_ref(name);
1482
1483         if (!prefixcmp(name, "heads/") ||
1484             !prefixcmp(name, "tags/") ||
1485             !prefixcmp(name, "remotes/"))
1486                 return alloc_ref_with_prefix("refs/", 5, name);
1487
1488         return alloc_ref_with_prefix("refs/heads/", 11, name);
1489 }
1490
1491 int get_fetch_map(const struct ref *remote_refs,
1492                   const struct refspec *refspec,
1493                   struct ref ***tail,
1494                   int missing_ok)
1495 {
1496         struct ref *ref_map, **rmp;
1497
1498         if (refspec->pattern) {
1499                 ref_map = get_expanded_map(remote_refs, refspec);
1500         } else {
1501                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1502
1503                 ref_map = get_remote_ref(remote_refs, name);
1504                 if (!missing_ok && !ref_map)
1505                         die("Couldn't find remote ref %s", name);
1506                 if (ref_map) {
1507                         ref_map->peer_ref = get_local_ref(refspec->dst);
1508                         if (ref_map->peer_ref && refspec->force)
1509                                 ref_map->peer_ref->force = 1;
1510                 }
1511         }
1512
1513         for (rmp = &ref_map; *rmp; ) {
1514                 if ((*rmp)->peer_ref) {
1515                         if (prefixcmp((*rmp)->peer_ref->name, "refs/") ||
1516                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1517                                 struct ref *ignore = *rmp;
1518                                 error("* Ignoring funny ref '%s' locally",
1519                                       (*rmp)->peer_ref->name);
1520                                 *rmp = (*rmp)->next;
1521                                 free(ignore->peer_ref);
1522                                 free(ignore);
1523                                 continue;
1524                         }
1525                 }
1526                 rmp = &((*rmp)->next);
1527         }
1528
1529         if (ref_map)
1530                 tail_link_ref(ref_map, tail);
1531
1532         return 0;
1533 }
1534
1535 int resolve_remote_symref(struct ref *ref, struct ref *list)
1536 {
1537         if (!ref->symref)
1538                 return 0;
1539         for (; list; list = list->next)
1540                 if (!strcmp(ref->symref, list->name)) {
1541                         hashcpy(ref->old_sha1, list->old_sha1);
1542                         return 0;
1543                 }
1544         return 1;
1545 }
1546
1547 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1548 {
1549         while (list) {
1550                 struct commit_list *temp = list;
1551                 temp->item->object.flags &= ~mark;
1552                 list = temp->next;
1553                 free(temp);
1554         }
1555 }
1556
1557 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1558 {
1559         struct object *o;
1560         struct commit *old, *new;
1561         struct commit_list *list, *used;
1562         int found = 0;
1563
1564         /* Both new and old must be commit-ish and new is descendant of
1565          * old.  Otherwise we require --force.
1566          */
1567         o = deref_tag(parse_object(old_sha1), NULL, 0);
1568         if (!o || o->type != OBJ_COMMIT)
1569                 return 0;
1570         old = (struct commit *) o;
1571
1572         o = deref_tag(parse_object(new_sha1), NULL, 0);
1573         if (!o || o->type != OBJ_COMMIT)
1574                 return 0;
1575         new = (struct commit *) o;
1576
1577         if (parse_commit(new) < 0)
1578                 return 0;
1579
1580         used = list = NULL;
1581         commit_list_insert(new, &list);
1582         while (list) {
1583                 new = pop_most_recent_commit(&list, TMP_MARK);
1584                 commit_list_insert(new, &used);
1585                 if (new == old) {
1586                         found = 1;
1587                         break;
1588                 }
1589         }
1590         unmark_and_free(list, TMP_MARK);
1591         unmark_and_free(used, TMP_MARK);
1592         return found;
1593 }
1594
1595 /*
1596  * Return true if there is anything to report, otherwise false.
1597  */
1598 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1599 {
1600         unsigned char sha1[20];
1601         struct commit *ours, *theirs;
1602         char symmetric[84];
1603         struct rev_info revs;
1604         const char *rev_argv[10], *base;
1605         int rev_argc;
1606
1607         /*
1608          * Nothing to report unless we are marked to build on top of
1609          * somebody else.
1610          */
1611         if (!branch ||
1612             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1613                 return 0;
1614
1615         /*
1616          * If what we used to build on no longer exists, there is
1617          * nothing to report.
1618          */
1619         base = branch->merge[0]->dst;
1620         if (read_ref(base, sha1))
1621                 return 0;
1622         theirs = lookup_commit_reference(sha1);
1623         if (!theirs)
1624                 return 0;
1625
1626         if (read_ref(branch->refname, sha1))
1627                 return 0;
1628         ours = lookup_commit_reference(sha1);
1629         if (!ours)
1630                 return 0;
1631
1632         /* are we the same? */
1633         if (theirs == ours)
1634                 return 0;
1635
1636         /* Run "rev-list --left-right ours...theirs" internally... */
1637         rev_argc = 0;
1638         rev_argv[rev_argc++] = NULL;
1639         rev_argv[rev_argc++] = "--left-right";
1640         rev_argv[rev_argc++] = symmetric;
1641         rev_argv[rev_argc++] = "--";
1642         rev_argv[rev_argc] = NULL;
1643
1644         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1645         strcpy(symmetric + 40, "...");
1646         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1647
1648         init_revisions(&revs, NULL);
1649         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1650         prepare_revision_walk(&revs);
1651
1652         /* ... and count the commits on each side. */
1653         *num_ours = 0;
1654         *num_theirs = 0;
1655         while (1) {
1656                 struct commit *c = get_revision(&revs);
1657                 if (!c)
1658                         break;
1659                 if (c->object.flags & SYMMETRIC_LEFT)
1660                         (*num_ours)++;
1661                 else
1662                         (*num_theirs)++;
1663         }
1664
1665         /* clear object flags smudged by the above traversal */
1666         clear_commit_marks(ours, ALL_REV_FLAGS);
1667         clear_commit_marks(theirs, ALL_REV_FLAGS);
1668         return 1;
1669 }
1670
1671 /*
1672  * Return true when there is anything to report, otherwise false.
1673  */
1674 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1675 {
1676         int num_ours, num_theirs;
1677         const char *base;
1678
1679         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1680                 return 0;
1681
1682         base = branch->merge[0]->dst;
1683         base = shorten_unambiguous_ref(base, 0);
1684         if (!num_theirs) {
1685                 strbuf_addf(sb,
1686                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1687                            "Your branch is ahead of '%s' by %d commits.\n",
1688                            num_ours),
1689                         base, num_ours);
1690                 if (advice_status_hints)
1691                         strbuf_addf(sb,
1692                                 _("  (use \"git push\" to publish your local commits)\n"));
1693         } else if (!num_ours) {
1694                 strbuf_addf(sb,
1695                         Q_("Your branch is behind '%s' by %d commit, "
1696                                "and can be fast-forwarded.\n",
1697                            "Your branch is behind '%s' by %d commits, "
1698                                "and can be fast-forwarded.\n",
1699                            num_theirs),
1700                         base, num_theirs);
1701                 if (advice_status_hints)
1702                         strbuf_addf(sb,
1703                                 _("  (use \"git pull\" to update your local branch)\n"));
1704         } else {
1705                 strbuf_addf(sb,
1706                         Q_("Your branch and '%s' have diverged,\n"
1707                                "and have %d and %d different commit each, "
1708                                "respectively.\n",
1709                            "Your branch and '%s' have diverged,\n"
1710                                "and have %d and %d different commits each, "
1711                                "respectively.\n",
1712                            num_theirs),
1713                         base, num_ours, num_theirs);
1714                 if (advice_status_hints)
1715                         strbuf_addf(sb,
1716                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1717         }
1718         return 1;
1719 }
1720
1721 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1722 {
1723         struct ref ***local_tail = cb_data;
1724         struct ref *ref;
1725         int len;
1726
1727         /* we already know it starts with refs/ to get here */
1728         if (check_refname_format(refname + 5, 0))
1729                 return 0;
1730
1731         len = strlen(refname) + 1;
1732         ref = xcalloc(1, sizeof(*ref) + len);
1733         hashcpy(ref->new_sha1, sha1);
1734         memcpy(ref->name, refname, len);
1735         **local_tail = ref;
1736         *local_tail = &ref->next;
1737         return 0;
1738 }
1739
1740 struct ref *get_local_heads(void)
1741 {
1742         struct ref *local_refs = NULL, **local_tail = &local_refs;
1743         for_each_ref(one_local_ref, &local_tail);
1744         return local_refs;
1745 }
1746
1747 struct ref *guess_remote_head(const struct ref *head,
1748                               const struct ref *refs,
1749                               int all)
1750 {
1751         const struct ref *r;
1752         struct ref *list = NULL;
1753         struct ref **tail = &list;
1754
1755         if (!head)
1756                 return NULL;
1757
1758         /*
1759          * Some transports support directly peeking at
1760          * where HEAD points; if that is the case, then
1761          * we don't have to guess.
1762          */
1763         if (head->symref)
1764                 return copy_ref(find_ref_by_name(refs, head->symref));
1765
1766         /* If refs/heads/master could be right, it is. */
1767         if (!all) {
1768                 r = find_ref_by_name(refs, "refs/heads/master");
1769                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1770                         return copy_ref(r);
1771         }
1772
1773         /* Look for another ref that points there */
1774         for (r = refs; r; r = r->next) {
1775                 if (r != head &&
1776                     !prefixcmp(r->name, "refs/heads/") &&
1777                     !hashcmp(r->old_sha1, head->old_sha1)) {
1778                         *tail = copy_ref(r);
1779                         tail = &((*tail)->next);
1780                         if (!all)
1781                                 break;
1782                 }
1783         }
1784
1785         return list;
1786 }
1787
1788 struct stale_heads_info {
1789         struct string_list *ref_names;
1790         struct ref **stale_refs_tail;
1791         struct refspec *refs;
1792         int ref_count;
1793 };
1794
1795 static int get_stale_heads_cb(const char *refname,
1796         const unsigned char *sha1, int flags, void *cb_data)
1797 {
1798         struct stale_heads_info *info = cb_data;
1799         struct refspec query;
1800         memset(&query, 0, sizeof(struct refspec));
1801         query.dst = (char *)refname;
1802
1803         if (query_refspecs(info->refs, info->ref_count, &query))
1804                 return 0; /* No matches */
1805
1806         /*
1807          * If we did find a suitable refspec and it's not a symref and
1808          * it's not in the list of refs that currently exist in that
1809          * remote we consider it to be stale.
1810          */
1811         if (!((flags & REF_ISSYMREF) ||
1812               string_list_has_string(info->ref_names, query.src))) {
1813                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1814                 hashcpy(ref->new_sha1, sha1);
1815         }
1816
1817         free(query.src);
1818         return 0;
1819 }
1820
1821 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1822 {
1823         struct ref *ref, *stale_refs = NULL;
1824         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1825         struct stale_heads_info info;
1826         info.ref_names = &ref_names;
1827         info.stale_refs_tail = &stale_refs;
1828         info.refs = refs;
1829         info.ref_count = ref_count;
1830         for (ref = fetch_map; ref; ref = ref->next)
1831                 string_list_append(&ref_names, ref->name);
1832         sort_string_list(&ref_names);
1833         for_each_ref(get_stale_heads_cb, &info);
1834         string_list_clear(&ref_names, 0);
1835         return stale_refs;
1836 }