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