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